Heat exchanger and refrigerant cycle device using the same

Abstract

A heat exchanger includes a plurality of fluid passages through which a heat-exchanger fluid including a liquid-phase fluid passes, a tank disposed above inlet parts of the fluid passages for distributing a flow of the heat-exchanger fluid to the fluid passages, and a retention member that is located above the inlet parts within the tank, for temporarily storing therein the liquid-phase fluid flowing into the tank. The retention member is constructed such that the liquid-phase fluid overflowing from the retention member falls toward the inlet part. Accordingly, the heat-exchanger fluid can be uniformly distributed into the fluid passages from the tank. For example, the heat exchanger can be used as an evaporator for a refrigerant cycle device having an ejector.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2006-12460 filed on Jan. 20, 2006, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to a heat exchanger including a plurality of fluid passages, which is suitably used as, for example, an evaporator for a refrigerant cycle device having an ejector. More particularly, the present invention relates to a liquid fluid retention portion provided in a tank of the heat exchanger.

BACKGROUND OF THE INVENTION

An ejector refrigerant cycle device is known which includes an ejector serving as refrigerant decompression means and refrigeration circulating means. The ejector refrigerant cycle device is useful for, for example, a vehicle air conditioner, or a vehicle refrigeration system for refrigerating and freezing loads on a vehicle, or the like. The refrigeration cycle is also useful for a fixed refrigeration cycle system, such as an air conditioner, a refrigerator, or a freezer. This kind of ejector refrigerant cycle device is disclosed in, for example, JP-B2-3322263 (corresponding to U.S. Pat. No. 6,477,857, U.S. Pat. No. 6,574,987).

JP-A-2005-308384 (corresponding to U.S. 2005/0268644A1) proposes an ejector refrigerant cycle device which includes a first evaporator disposed at an outlet side of an ejector with an outlet side of the first evaporator connected to a suction side of a compressor, a refrigerant branch passage branched from an upstream part of the ejector, and a second evaporator disposed at a downstream side in the refrigerant branch passage with an outlet side of the second evaporator connected to a refrigerant suction port of the ejector.

Furthermore, in the ejector refrigerant cycle device of the JP-A-2005-308384, a tank into which the refrigerant passing through the refrigerant branch passage flows is disposed on the upper side of the second evaporator. The tank is adapted to distribute the refrigerant to a plurality of refrigerant passages (tubes) of the second evaporator. This can achieve a simple structure for distribution of the refrigerant to the plurality of tubes of the second evaporator. More specifically, the branched refrigerant on the refrigerant branch passage flows into the tank of the second evaporator. That is, only a part of the refrigerant circulating the refrigeration cycle flows into the tank of the second evaporator, resulting in a small flow rate of the refrigerant flowing into the tank.

Thus, the refrigerant reaches directly one of spaces within the tank near an inlet for the refrigerant, but does not reach readily and directly another space apart from the refrigerant inlet, thereby causing insufficient uniformity in distribution of the refrigerant to the plurality of tubes.

As a result, it is difficult to make an endothermic (cooling) effect of the plurality of tubes uniform, thereby disadvantageously causing insufficient uniformity in temperature distribution of air passing through the second evaporator.

Even in another heat exchanger including a tank for distributing a heat-exchanger fluid (for example, hot water or the like) to a plurality of inside passages, the same problem is raised when a flow rate of the heat-exchanger fluid is small.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the present invention to provide a heat exchanger which can uniformly distribute fluid to a plurality of fluid passages even when a flow rate of the fluid is small. It is another object of the present invention to provide a refrigerant cycle device having an evaporator which can uniformly distribute refrigerant into a plurality of refrigerant passages.

According to an aspect of the present invention, a heat exchanger includes a plurality of tubes defining fluid passages through which a heat-exchanger fluid including at least a liquid-phase fluid passes, a tank disposed above an inlet part of the plurality of fluid passages for distributing a flow of the heat-exchanger fluid to the fluid passages, and a retention member, located above the inlet part within the tank, for temporarily storing therein the liquid-phase fluid flowing into the tank. In the heat exchanger, the retention member is constructed such that the liquid-phase fluid overflowing from the retention member falls toward the inlet part. Accordingly, liquid-phase refrigerant flowing into the tank is stored in the retention member, and the liquid-phase fluid overflowing from the retention member flows into the fluid passages. Therefore, it can restrict the liquid-phase refrigerant from easily directly flowing into a part of the fluid passages, thereby the liquid-phase refrigerant can uniformly introduce into all the fluid passages even when a flow amount of the fluid introducing into the heat exchanger is small.

For example, the retention member has a mountain section protruding from a horizontal surface. In this case, the mountain section and an inner wall surface of the tank extending in a vertical direction define a recessed retention portion in which the liquid-phase fluid is temporarily stored, and the mountain section of the retention member includes an apex area having a hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing. Here, a flexed angle (θ) of the mountain section may be in a range from 30 degrees to 170 degrees, and the hole may be provided in the mountain section to be superimposed over the inlet part.

Alternatively, the retention member includes a tilt plate tilted in the tank with respective to a horizontal direction. In this case, the tilt plate has: a lower part, which forms a retention portion in which the liquid-phase fluid is temporarily stored, together with an inner wall surface of the tank; and an upper part having a hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing. Alternatively, the retention member includes a plate member having a recessed part for defining a retention portion in which the liquid-phase fluid is temporarily stored. In this case, the plate member is separated from an inner wall of the tank to form the hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing.

The heat exchanger can be used as one evaporator in a refrigerant cycle device. For example, the refrigerant cycle device includes a compressor for compressing refrigerant, a radiator for cooling the refrigerant from the compressor, an ejector which has a nozzle part for decompressing the refrigerant from the radiator and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from a jet port of the nozzle part, and the one evaporator in which the refrigerant to be drawn into the refrigerant suction port is evaporated. In this case, the one evaporator includes a plurality of tubes defining refrigerant passages through which refrigerant including at least a liquid-phase refrigerant passes, and a tank disposed above an inlet part of the plurality of refrigerant passages for distributing a flow of the refrigerant to the refrigerant passages. Furthermore, a retention member is located in the tank above the inlet part for temporarily storing therein the liquid-phase refrigerant flowing into the tank, and the retention member is provided to form a hole through which the liquid-phase refrigerant overflowing from the retention member falls toward the inlet part. Accordingly, the refrigerant can be uniformly distributed into the refrigerant passages in the one evaporator.

For example, the refrigerant cycle device may be provided with another evaporator for evaporating refrigerant. In this case, the another evaporator may include a refrigerant inlet coupled to a refrigerant outlet of the ejector and a refrigerant outlet coupled to a refrigerant suction side of the compressor, and the one evaporator and the another evaporator may be integrated with the ejector. The ejector may be integrated with at least the one evaporator. In this case, the ejector may be located in the tank of the one evaporator or may be integrated with the one evaporator outside of the one evaporator.

Furthermore, the other components such as a decompression member, a gas-liquid separator and the another evaporator may be further integrated with the one evaporator, except for the ejector.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional objects and advantages of the present invention will be more readily apparent from the following detailed description of embodiments when taken together with the accompanying drawings. In the drawings:

FIG. 1 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to a first embodiment of the invention;

FIG. 2 is an exploded perspective view showing a schematic structure of an integrated unit in the first embodiment;

FIG. 3 is a schematic cross-sectional view of an evaporator tank in the integrated unit of FIG. 2;

FIG. 4 is a longitudinal sectional view of the evaporator tank in the integrated unit of FIG. 2;

FIG. 5 is an enlarged sectional view taken along the line V-V of FIG. 4;

FIG. 6 is a perspective view of a connection block and an intervening plate in the integrated unit of FIG. 2;

FIG. 7 is a perspective view of an ejector fixing plate in the integrated unit of FIG. 2;

FIG. 8 is a perspective view of an upper and lower partition plate in the integrated unit of FIG. 2;

FIG. 9 is a perspective view of a spacer in the integrated unit of FIG. 2;

FIG. 10 is a perspective view of a refrigerant retention plate in the integrated unit of FIG. 2;

FIG. 11 is a schematic cross-sectional view of a lower space in an evaporator tank of the integrated unit of FIG. 2;

FIG. 12 is a schematic perspective view showing an entire refrigerant flow path in the integrated unit of FIG. 2;

FIG. 13 is a perspective view showing a schematic structure of an integrated unit in an example 1 of the first embodiment;

FIG. 14 is a schematic cross-sectional view of an evaporator tank of the integrated unit of FIG. 13;

FIG. 15 is a side view of the evaporator tank of FIG. 14;

FIG. 16 is a perspective view showing a schematic structure of an integrated unit in an example 2;

FIG. 17 is a schematic cross-sectional view of an evaporator tank of the integrated unit of FIG. 16;

FIG. 18 is a side view of the evaporator tank of FIG. 17;

FIG. 19 is a perspective view showing a schematic structure of an integrated unit in an example 3;

FIG. 20 is a schematic longitudinal sectional view of an evaporator tank of the integrated unit of FIG. 19;

FIG. 21 is a cross-sectional view of the evaporator tank of the integrated unit of FIG. 19;

FIG. 22 is a perspective view showing a schematic structure of an integrated unit in an example 4;

FIG. 23 is a schematic longitudinal sectional view of an evaporator tank of the integrated unit of FIG. 22;

FIG. 24 is a side view of the evaporator tank of FIG. 23;

FIG. 25 is a perspective view showing a schematic structure of an integrated unit in an example 5, together with a sectional view of an external cassette;

FIG. 26 is a perspective view showing a schematic structure of an integrated unit in an example 6, together with a sectional view of an external cassette;

FIG. 27 is a perspective view of a refrigerant retention plate according to a second embodiment of the present invention;

FIG. 28 is a schematic cross-sectional view of a lower space of an evaporator tank of an integrated unit according to the second embodiment;

FIG. 29 is a perspective view of a refrigerant retention plate according to a third embodiment of the present invention;

FIG. 30 is a cross-sectional view of a lower space of an evaporator tank of an integrated unit according to the third embodiment;

FIG. 31 is a cross-sectional view of a lower space of an evaporator tank of an integrated unit according to a fourth embodiment of the present invention;

FIG. 32 is a longitudinal sectional view of an evaporator tank of an integrated unit according to a fifth embodiment of the present invention;

FIG. 33 is a longitudinal sectional view of an evaporator tank of an integrated unit according to a sixth embodiment of the present invention;

FIG. 34 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to a seventh embodiment of the present invention;

FIG. 35 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to an eighth embodiment of the present invention;

FIG. 36 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to a ninth embodiment of the present invention;

FIG. 37 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to a tenth embodiment of the present invention;

FIG. 38 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to an eleventh embodiment of the present invention; and

FIG. 39 is a refrigerant circuit diagram of an ejector refrigerant cycle device for a vehicle according to a twelfth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

A first embodiment of the invention will be described below with reference to FIGS. 1 to 12. In the embodiment, a heat exchanger of the invention will be typically used for a refrigeration cycle of an ejector refrigerant cycle device. A unit for the refrigeration cycle is a heat exchanger unit, such as an evaporator unit, or an ejector-equipped evaporator unit, for example.

This unit is connected to other components of the refrigeration cycle, including a condenser, a compressor, and the like, via piping to constitute a refrigerant cycle device including an ejector. The unit of the embodiment is used for application to an indoor equipment (evaporator) for cooling air. The unit may be used as an outdoor equipment in other embodiments.

In an ejector refrigerant cycle device 10 shown in FIG. 1, a compressor 11 for drawing and compressing refrigerant is driven by an engine for vehicle traveling (not shown) via an electromagnetic clutch 11a, a belt, or the like.

As the compressor 11, may be used either a variable displacement compressor which can adjust a refrigerant discharge capability by a change in discharge capacity, or a fixed displacement compressor which can adjust a refrigerant discharge capability by changing an operating ratio of the compressor through engagement and disengagement of an electromagnetic clutch 11a. If an electric compressor is used as the compressor 11, the refrigerant discharge capability can be adjusted or regulated by adjustment of the number of revolutions of an electric motor.

A radiator 12 is disposed on a refrigerant discharge side of the compressor 11. The radiator 12 exchanges heat between the high-pressure refrigerant discharged from the compressor 11 and an outside air (air outside a compartment of a vehicle) blown by a cooling fan (not shown) thereby to cool the high-pressure refrigerant.

As the refrigerant for the ejector refrigerant cycle device 10 in the embodiment, is used a refrigerant whose high pressure does not exceed a critical pressure, such as a flon-based refrigerant, or a HC-based refrigerant, so as to form a vapor-compression subcritical cycle. Thus, the radiator 12 serves as a condenser for cooling and condensing the refrigerant.

A liquid receiver 12a is provided at a refrigerant outlet side of the radiator 12. The liquid receiver 12a has an elongated tank-like shape, as is known in the art, and constitutes a vapor-liquid separator for separating the refrigerant into vapor and liquid phases to store therein an excessive liquid refrigerant of the refrigerant cycle. At a refrigerant outlet of the liquid receiver 12a, the liquid refrigerant is derived from the lower part of the interior in the tank-like shape. In the embodiment, the liquid receiver 12a is integrally formed with the radiator 12.

The radiator 12 may have a known structure which includes a first heat exchanger for condensation positioned on the upstream side of a refrigerant flow, the liquid receiver 12a for allowing the refrigerant introduced from the first heat exchanger for condensation and for separating the refrigerant into vapor and liquid phases, and a second heat exchanger for supercooling the saturated liquid refrigerant from the liquid receiver 12a.

A thermal expansion valve 13 is disposed on an outlet side of the liquid receiver 12a. The thermal expansion valve 13 is a decompression unit for decompressing the liquid refrigerant from the liquid receiver 12a, and includes a temperature sensing part 13a disposed in a refrigerant suction passage of the compressor 11.

The thermal expansion valve 13 detects a degree of superheat of the refrigerant at the compressor suction side based on the temperature and pressure of the suction side refrigerant of the compressor 11, and adjusts an opening degree of the valve (refrigerant flow rate) such that the superheat degree of the refrigerant on the compressor suction side becomes a predetermined value which is preset, as is known in the art.

An ejector 14 is disposed at a refrigerant outlet side of the thermal expansion valve 13. The ejector 14 is decompression means for decompressing the refrigerant as well as refrigerant circulating means (kinetic vacuum pump) for circulating the refrigerant by a suction effect (entrainment effect) of the refrigerant flow ejected at high speed.

The ejector 14 includes a nozzle part 14a for further decompressing and expanding the refrigerant (the middle-pressure refrigerant) by restricting a path area of the refrigerant having passed through the expansion valve 13 to a small level, and a refrigerant suction port 14b disposed in the same space as a refrigerant jet port of the nozzle part 14a for drawing the vapor-phase refrigerant from a second evaporator 18 as described later.

A mixer 14c is provided on the downstream side part of the refrigerant flow of the nozzle part 14a and the refrigerant suction part 14b, for mixing a high-speed refrigerant flow from the nozzle part 14a and a sucked refrigerant from the refrigerant suction port 14b. A diffuser 14d serving as a pressure-increasing portion is provided on the downstream side of the refrigerant flow of the mixer 14c. The diffuser 14d is formed in such a manner that a path area of the refrigerant is generally increased toward downstream from the mixer 14c. The diffuser 14d serves to increase the refrigerant pressure by decelerating the refrigerant flow, that is, to convert the speed energy of the refrigerant into the pressure energy.

A first evaporator 15 is connected to an outlet 14e (the tip end of the diffuser 14d) of the ejector 14. The outlet side of the first evaporator 15 is connected to a suction side of the compressor 11.

On the other hand, a refrigerant branch passage 16 is provided to be branched from an inlet side of the ejector 14. That is, the refrigerant branch passage 16 is branched at a position between the refrigerant outlet of the thermal expansion valve 13 and the refrigerant inlet of the nozzle part 14a of the ejector 14. The downstream side of the refrigerant branch passage 16 is connected to the refrigerant suction port 14b of the ejector 14. A point Z indicates a branch point of the refrigerant branch passage 16.

In the refrigerant branch passage 16, a throttle 17 is disposed. On the refrigerant flow downstream side away from the throttle 17, a second evaporator 18 is disposed. The throttle 17 serves as a decompression unit which performs a function of adjusting a refrigerant flow rate into the second evaporator 18. More specifically, the throttle 17 can be constructed with a fixed throttle, such as a capillary tube, or an orifice.

In the first embodiment, two evaporators 15 and 18 are incorporated into an integrated structure with an arrangement as described later. These two evaporators 15 and 18 are accommodated in a case not shown, and the air (air to be cooled) is blown by a common electric blower 19 through an air passage formed in the case in the direction of an arrow “A”, so that the blown air is cooled by the two evaporators 15 and 18.

The cooled air by the two evaporators 15 and 18 is fed to a common space to be cooled (not shown). This causes the two evaporators 15 and 18 to cool the common space to be cooled. Among these two evaporators 15 and 18, the first evaporator 15 connected to a main flow path on the downstream side of the ejector 14 is disposed on the upstream side (upwind side) of the air flow A, while the second evaporator 18 connected to the refrigerant suction port 14b of the ejector 14 is disposed on the downstream side (downwind side) of the air flow A.

When the ejector refrigerant cycle device 10 of the embodiment is used as a refrigeration cycle for a vehicle air conditioner, the space within the vehicle compartment is a space to be cooled. When the ejector refrigerant cycle device 10 of the embodiment is used for a refrigeration cycle for a freezer car, the space within the freezer and refrigerator of the freezer car is the space to be cooled.

In the embodiment, the ejector 14, the first and second evaporators 15 and 18, and the throttle 17 are incorporated into one integrated unit 20. Now, specific examples of the integrated unit 20 will be described below in detail with reference to FIGS. 2 to 11.

FIG. 2 is an exploded perspective view showing the entire schematic structure of the first and second evaporators 15 and 18. FIG. 3 is a cross-sectional view of upper tanks for the first and second evaporators 15 and 18, FIG. 4 is a schematic longitudinal sectional view of the upper tank of the second evaporator 18, and FIG. 5 is an enlarged sectional view taken along the line V-V of FIG. 4.

First, an example of the integrated structure including the two evaporators 15 and 18 will be explained below with reference to FIG. 2. In the embodiment of FIG. 2, the two evaporators 15 and 18 can be formed integrally into a completely single evaporator structure. Thus, the first evaporator 15 constitutes an upstream side area of the single evaporator structure in the direction of the air flow A, while the second evaporator 18 constitutes a downstream side area of the single evaporator structure in the direction of the air flow A.

The first evaporator 15 and the second evaporator 18 have the same basic structure, and include heat exchange cores 15a and 18a, and tanks 15b, 15c, 18b, and 18c positioned on both upper and lower sides of the heat exchange cores 15a and 18a, respectively.

The heat exchanger cores 15a and 18a respectively include a plurality of tubes 21 extending in a tube longitudinal direction (e.g., vertically in FIG. 2). The tube 21 corresponds to a heat source fluid passage in which a heat source fluid for performing a heat exchange with a heat-exchange medium flows. One or more passages for allowing a heat-exchange medium, namely air to be cooled in the embodiment, to pass therethrough are formed between these tubes 21.

Between these tubes 21, fins 22 are disposed, so that the tubes 21 can be connected to the fins 22. Each of the heat exchange cores 15a and 18a is constructed of a laminated structure of the tubes 21 and the fins 22. These tubes 21 and fins 22 are alternately laminated in a lateral direction of the heat exchange cores 15a and 18a. In other embodiments or examples, any appropriate structure without using the fins 22 in the cores 15a and 18a may be employed.

In FIG. 2, only some of the fins 22 are shown, but in fact the fins 22 are disposed over the whole areas of the heat exchange cores 15a and 18a, and the laminated structure including the tubes 21 and the fins 22 is disposed over the whole areas of the heat exchange cores 15a and 18a. The blown air by the electric blower 19 is adapted to pass through voids (clearances) in the laminated structure.

The tube 21 constitutes the refrigerant passage through which refrigerant flows, and is made of a flat tube having a flat cross-sectional shape in the air flow direction A. The fin 22 is a corrugated fin made by bending a thin plate in a wave-like shape, and is connected to a flat outer surface of the tube 21 to expand a heat transfer area of the air side.

The tubes 21 of the heat exchanger core 15a and the tubes 21 of the heat exchanger core 18a independently constitute the respective refrigerant passages. The tanks 15b and 15c on both upper and lower sides of the first evaporator 15, and the tanks 18b and 18c on both upper and lower sides of the second evaporator 18 independently constitute the respective refrigerant passage spaces.

As shown in FIG. 5, the tanks 15b and 15c on both upper and lower sides of the first evaporator 15 have tube fitting holes 15d into which upper and lower ends of the tube 21 of the heat exchange core 15a are inserted and attached, so that both the upper and lower ends of the tube 21 are communicated with the inside space of the tanks 15b and 15c, respectively.

Similarly, the tanks 18b and 18c on both upper and lower sides of the second evaporator 18 have tube fitting holes 18d into which upper and lower ends of the tube 21 of the heat exchange core 18a are inserted and attached, so that both the upper and lower ends of the tube 21 are communicated with the inside space of the tanks 18b and 18c, respectively.

Thus, the tanks 15b, 15c, 18b, and 18c disposed on both upper and lower sides serve to distribute the refrigerant flows to the respective tubes 21 of the heat exchange cores 15a and 18a, and to collect the refrigerant flows from these tubes 21.

In FIG. 5, only the tube fitting holes on the side of the upper tanks 15b and 18b among the tube fitting holes 15d and 18d of the tanks 15b, 15c, 18b, and 18c on the upper and lower sides are shown. In contrast, since the tube fitting holes on the side of the lower tanks 15c and 18c have the same structure as that of the tube fitting holes on the side of the upper tanks 15b and 18b, representation of the tube fitting holes of the lower tanks 15c and 18c side is omitted.

Since the two upper tanks 15b and 18b are adjacent to each other, the two upper tanks 15b and 18b can be molded integrally. The same can be made for the two lower tanks 15c and 18c. It is apparent that the two upper tanks 15b and 18b may be molded independently as independent components, and that the same can be made for the two lower tanks 15c and 18c.

In the embodiment, as shown in FIGS. 2 and 5, the two upper tanks 15b and 18b are molded by division into a bottom-side half member 60 (first member), an upper-side half member 61 (second member), and a cap 62.

More specifically, the bottom-side half member 60 has a substantially W-shaped section which is obtained by integrally forming respective bottom-side half parts of the two upper tanks 15b and 18b. The upper-side half member 61 has a substantially M-shaped section which is obtained by integrally forming respective upper-side half parts of the two upper tanks 15b and 18b.

In the center area of the substantially W-shaped section of the bottom-side half member 60, a flat surface part 60a is formed. In the center area of the substantially M-shaped section of the upper-side half member 61, a flat surface part 61a is formed. Combining the bottom-side half member 60 with the upper-side half member 61 brings the flat surface part 60a into contact with the flat surface part 61a to form two cylindrical shapes. One ends of the two cylindrical shapes (right end of FIG. 2) in the longitudinal direction are closed with the cap 62, constituting the two upper tanks 15b and 18b.

Material suitable for use in the evaporator components, such as the tube 21, the fin 22, the tanks 15b, 15c, 18b, and 18c, may include, for example, aluminum, which is metal with excellent thermal conductivity and brazing property. By forming each component using the aluminum material, the entire structures of the first and second evaporators 15 and 18 can be assembled integrally with brazing.

In the embodiment, a capillary tube 17a or the like constituting the throttle 17 and a connection block 23 shown in FIG. 2 are assembled integrally to the first and second evaporators 15 and 18 with brazing.

On the other hand, the ejector 14 has the nozzle 14a in which a fine passage is formed with high accuracy. Brazing of the ejector 14 may cause heat deformation of the nozzle part 14a at high temperature in brazing (at brazing temperature of aluminum: about 600° C.). This will disadvantageously result in the fact that the shape and dimension or the like of the passage of the nozzle part 14a cannot be maintained according to a predetermined design.

Thus, the ejector 14 is assembled to the evaporator side after integrally brazing the first and second evaporators 15 and 18, the connection block 23, and the capillary tube 17a, and the like.

More specifically, an assembly structure including the ejector 14, the capillary tube 17a, and the connection block 23 and the like will be explained below. The capillary tube 17a and the connection block 23 are made of the same aluminum material as that of the evaporator components.

Referring to FIG. 5, the capillary tube 17a is disposed to be sandwiched in a valley-like part 61b (recess part between the tanks 15b, 18b) formed on the flat surface part 61a of the upper-side half member 61 of the upper tanks 15b and 18b.

The connection block 23 is a member brazed and fixed to one side (left side in FIG. 2) of each of the upper tanks 15b and 18b in the tank longitudinal direction among the first and second evaporators 15 and 18. The connection block 23 includes a refrigerant inlet 25 of the integrated unit 20 shown in FIG. 1, one refrigerant outlet 26, and an ejector inlet part 63 for assembling the ejector 14 to the evaporator side.

As shown in FIGS. 3 and 6, the refrigerant inlet 25 branches, in a midstream of the connection block 23 in the thickness direction, into a main passage 25a serving as a first passage directed to the inlet of the ejector 14, and a branch passage 16 serving as a second passage directed to the inlet of the capillary tube 17a. This part of the branch passage 16 corresponds to an inlet part of the branch passage 16 shown in FIG. 1. Thus, a branch point Z of FIG. 1 is provided inside the connection block 23.

The refrigerant outlet 26 is composed of one simple passage hole (circular hole or the like) penetrating the connection block 23 in the thickness direction as shown in FIGS. 2 and 6.

The connection block 23 is brazed and fixed to the side of the upper tanks 15b and 18b via an intervening plate 64. The intervening plate 64 serves to form the main passage 25a and the branch passage 16 as described above by being integrally fixed with the connection block 23, and to fix the ejector 14 in the longitudinal direction.

In the intervening plate 64 molded of the aluminum material, a main passage side opening 64a in communication with the main passage 25a of the connection block 23, a branch passage side opening 64b in communication with the branch passage 16 of the connection block 23, and a refrigerant outlet side opening 64c in communication with the refrigerant outlet 26 of the connection block 23 are formed.

A cylindrical part 64d is formed at a peripheral part of the main passage side opening 64a to be inserted into the upper tank 18b. An annular flange 64e protruding in the inner diameter direction of the cylindrical part 64d is formed on the tip of the cylindrical part 64d.

A first lug 64f (claw portion) protruding from the intervening plate 64 toward the evaporator side is caulked and fastened to the upper tanks 15b and 18b, so that the intervening plate 64 can be temporarily fixed to the evaporator side. Furthermore, a second lug 64g (claw portion) protruding from the intervening plate 64 toward the connection block 23 is caulked and fastened to the connection block 23, so that the connection block 23 can be temporarily fixed to the evaporator side.

The branch passage side opening 64b of the intervening plate 64 is brazed and seal-connected to the upstream side end (left end shown in FIG. 2) of the capillary tube 17a.

With such an arrangement of the connection block 23 and the intervening plate 64, the refrigerant outlet 26 of the connection block 23 communicates with a left space 31 of the upper tank 15b via the refrigerant outlet side opening 64c of the intervening plate 64, and the main passage 25a of the connection block 23 communicates with a left space 27 of the upper tank 18b via the main passage side opening 64a of the intervening plate 64. Moreover, the connection block 23 and the intervening plate 64 are brazed to the side ends of the upper tanks 15b and 18b, with the branch passage 16 of the connection block 23 communicating with the upstream side end 17c of the capillary tube 17a via the branch passage side opening 64b of the intervening plate 64.

An ejector fixing plate 65 is a member which serves to fix the diffuser 14d of the ejector 14, while partitioning the inside space of the upper tank 18b into the left space 27 and a right space 28, as shown in FIGS. 2-4. The left space 27 of the upper tank 18b acts as a collecting tank for collecting the refrigerants having passed through a plurality of tubes 21 in the second evaporator 18.

The ejector fixing plate 65 is disposed in a substantial center portion of the inside space of the upper tank 18b of the second evaporator 18 in the longitudinal direction, and brazed to the inside wall surface of the upper tank 18b.

As shown in FIG. 7, the ejector fixing plate 65 is made of aluminum material, and includes a flat plate part 65a partitioning the upper tank 18b in the lateral direction of FIG. 7, a cylindrical part 65b protruding from the flat plate part 65a in the longitudinal direction of the upper tank 18b, and a lug 65c protruding upward from the upper end of the flat plate part 65a.

Inside the cylindrical part 65b, a through hole is formed to penetrate the ejector fixing plate 65 laterally. The lug 65c penetrates a slit-like hole 66 on the upper surface of the upper tank 18b, and is caulked and fastened to the upper tank 18b as shown in FIG. 4. This can temporarily fix the ejector fixing plate 65 to the upper tank 18b.

Referring back to FIG. 4, the downstream side end (right end) 17d of the capillary tube 17a is inserted into the upper tank 18b in the direction of lamination of the tubes 21 (laterally in FIG. 4). More specifically, the downstream side end 17d of the capillary tube 17a is inserted into a through hole 62a of the cap 62 of the upper tank 18b to be opened inside of the right space 28. Sealing connection is formed between the outer peripheral surface of the capillary tube 17a and the through hole 62a of the cap 62 with brazing.

An upper and lower partition plate 67 is disposed in a substantial center area of the right space 28 of the upper tank 18b in the vertical direction. The upper and lower partition plate 67 serves to partition the right space 28 into two spaces in the up-down direction, that is, into an upper space 69 and a lower space 70, which serves as a distribution tank for distributing the refrigerant to the plurality of tubes 21 of the second evaporator 18.

The upper and lower partition plate 67 is made of an aluminum material, and brazed to the inner wall surface of the upper tank 18b. The partition plate 67 has a plate shape extending in the longitudinal direction of the upper tank 18b as a whole as shown in FIG. 8.

More specifically, the upper and lower partition plate 67 includes a flat plate surface 67a extending in the longitudinal direction of the upper tank 18b, and first and second flexed parts 67b and 67c which are flexed (bent) at right angles in opposite directions to each other at two ends of the flat plate surface 67a in the longitudinal direction.

The first flexed part 67b is flexed upward from one end of the flat plate surface 67a which is nearer to the downstream side end 17d of the capillary tube 17a (on the right side of FIG. 4), while the second flexed part 67c is flexed downward from the other end of the flat plate surface 67a.

As shown in FIG. 5, the flat plate surface 67a is slanted so as to be lowered from the first evaporator 15 side to the second evaporator 18 side. At the root of the first flexed part 67b, a rib 67d protruding toward the flat plate surface 67a in a triangle shape is integrally formed. The rib 67d enhances the rigidity of the first flexed part 67b, thereby maintaining a flexed angle of the first flexed part 67b at the right angle.

As shown in FIG. 4, a lug 67e protruding upward from the tip (upper end) of the first flexed part 67b penetrates the slit-like hole 68 on the upper surface of the upper tank 18b, and thus is caulked and fastened to the upper tank 18b. Thus, the upper and lower partition plate 67 can be temporarily fixed to the upper tank 18b.

By forming the first flexed part 67b in the upper and lower partition plate 67, the lower space 70 is expanded upward more on the downstream side end 17d of the capillary tube 17a (on the right side of FIG. 4) than at the first flexed part 67b. That is, in the space on the side of the downstream side end 17d of the capillary tube 17a among the right space 28, the upper space 69 is not formed, and the lower space 70 is formed over the entire vertical area of the right space 28.

As shown in FIG. 8, on one end of the second flexed part 67c side of the flat plate surface 67a of the upper and lower partition plate 67 (on the left side in FIG. 8), a recess 67f which is recessed toward the lower space 70 side is formed. The recess 67f includes a cylindrical recess part 67g and a conic recess part 67h.

The cylindrical recess part 67g has a shape extending in the longitudinal direction of the flat plate surface 67a at an end on the second flexed part 67c side of the flat plate surface 67a (on the left side in FIG. 8). The conic recess part 67h is formed successively in connection with the cylindrical recess part 67g near the first flexed part 67b side (on the right side in FIG. 8) rather than the cylindrical recess part 67g. The conic recess part 67h has such a shape that the cylindrical recess part 67g side of the recess part 67h is deep, and that the farther from the cylindrical recess part 67g, the shallower the recess part 67h.

The ejector 14 is made of a metal material such as copper, or aluminum. Alternatively, the ejector 14 may be made of resin (non-metal material). After a step of integrally brazing and assembling the first and second evaporators 15 and 18 or the like (a step of brazing), the ejector 14 is inserted into the upper tank 18b through holes including the ejector inlet 63 of the connection block 23, and the main passage side opening 64a of the intervening plate 64.

The tip end 14e of the ejector 14 in the longitudinal direction shown in FIG. 3 corresponds to the outlet part 14e of the ejector 14 shown in FIG. 1. This ejector tip end 14e is inserted into the cylindrical part 65b of the ejector fixing plate 65 to be sealed and fixed using an O ring 29a.

As shown in FIG. 4, the ejector tip end 14e is disposed in such a position that it crosses the flat plate surface 67a of the upper and lower partition plate 67 in the vertical direction. The recess 67f is formed in the upper and lower partition plate 67, and the outer peripheral surface of the diffuser 14d of the ejector 14 is disposed in and on the cylindrical recess part 67g of the recess 67f. This allows the entire tip end 14e of the ejector to be opened in the upper space 69 of the right space 28 within the upper tank 18b. The refrigerant suction port 14b of the ejector 14 is in communication with the left space 27 of the upper tank 18b of the second evaporator 18.

As shown in FIG. 3, at a substantial center of the inside space of the upper tank 15b of the first evaporator 15 in the tank longitudinal direction, is disposed a left and right partition plate 30, which partitions the inside space of the upper tank 15b into two spaces in the tank longitudinal direction, that is, the left space 31 and a right space 32.

The left space 31 serves as the collecting tank for collecting the refrigerants having passed through the plurality of tubes 21 of the first evaporator 15. The right space 32 serves as the distribution tank for distributing the refrigerant to the plurality of tubes 21 of the first evaporator 15.

As shown in FIGS. 4 and 5, on the flat plate surface 61a of the upper-side half member 61 of the upper tanks 15b and 18b, a recess part 61c is formed at a part positioned in the upper space 69 of the right space 28 within the upper tank 18b.

A plurality of recess parts 61c are arranged in the direction of lamination of the tubes 21 (laterally in FIG. 4). A plurality of communication holes 71 are formed by spaces enclosed by these recess parts 61c and the flat plate surface 60a of the bottom-side half member 60 of the upper tanks 15b and 18b.

The upper space 69 of the right space 28 within the upper tank 18b, and the right space 32 of the upper tank 15b of the first evaporator 15 are communicated with each other via the plurality of communication holes 71.

The plurality of recess parts 61c may be formed in such a shape that they are connected into one body, thereby forming the communication holes 71 across the entire area in the upper space 69 in the lateral direction (in the direction of lamination of the tubes 21).

The left end of the ejector 14 (left end of FIG. 3) in the longitudinal direction corresponds to the inlet part of the nozzle part 14a of FIG. 1. This left end is fitted into and seal-fixed to the inner peripheral surface of the cylindrical part 64d of the intervening plate 64 using an O ring 29b.

In the embodiment, the ejector 14 is fixed in the longitudinal direction as follows. First, after inserting the ejector 14 from the ejector inlet part 63 of the connection block 23 into the upper tank 18b, the spacer 72 is inserted into the ejector inlet part 63, and then external threads on the outer peripheral surface of a columnar plug 73 mesh with internal threads on the inner peripheral surface of the ejector inlet part 63. In the embodiment, the spacer 72 and the plug 73 are made of aluminum material, respectively.

As shown in FIG. 9, the spacer 72 includes an annular part 72a, and a protruding part 72b protruding from a part of the annular part 72a in an axial direction. Thus, when the plug 73 meshes with the ejector inlet part 63, the protruding part 72b of the spacer 72 presses the left end of the ejector 14 in the direction of insertion of the ejector 14.

On the other hand, on the left end of the ejector 14, an annular part 74 whose diameter is larger than the ejector itself is formed. Thus, when the protruding part 72b of the spacer 72 is pressed against the left end of the ejector 14 in the insertion direction of the ejector 14, the annular part 74 of the ejector 14 is pressed against the flange 64e of the intervening plate 64. This can fix the ejector 14 in the longitudinal direction of the ejector 14.

If the protruding part 72b is formed to protrude from the entire circumference of the annular part 72a of the spacer 72 so as to make the spacer 72 in a simple cylindrical shape, the main passage 25a of the connection block 23 would be closed by the spacer 72.

In contrast, since in the embodiment, the protruding part 72b of the spacer 72 is formed to protrude from only one part of the annular part 72a of the spacer 72, the ejector 14 can be fixed in the longitudinal direction without closing the main passage 25a of the connection block 23.

The outer peripheral surface of the cylindrical plug 73 is fitted into and seal-fixed to the inner peripheral surface of the ejector inlet part 63 of the connection block 23 using the O ring 29c.

As shown in FIGS. 4 and 5, a refrigerant retention plate 75 (refrigerant staying plate) is disposed in the lower space 70 of the right space 28 within the upper tank 18b. The refrigerant retention plate 75 is a member which serves to uniform the distribution of the refrigerant to the plurality of tubes 21 of the second evaporator 18, and corresponds to a retention member of the invention.

The refrigerant retention plate 75 of the embodiment is made of aluminum material, and has a plate-like shape with a mountain-like section, extending in the direction of lamination of the tubes 21 (laterally in FIG. 4). The mountain-like section protrudes from a horizontal surface in the refrigerant retention plate 75.

Referring to FIG. 10, a plurality of holes 75a are formed on the top part of the refrigerant retention plate 75 having the mountain-like section, in the direction of lamination of the tubes 21. Between these holes 75a, a connection part 75b having a mountain-like section is formed. The connection part 75b can ensure the rigidity of the refrigerant retention plate 75 even when the holes 75a are formed in the refrigerant retention plate 75.

As shown in FIG. 10, the hole 75a has a shape entirely extending in the direction of lamination of the tubes 21. Since the edge of the hole 75a extending in the lamination direction of the tubes 21 has a wave-like shape, the edge has a plurality of apexes 75c distorted outward. In contrast, another edge of the hole 75a extending in a direction perpendicular to the direction of lamination of the tubes 21 has a linear shape, as shown in FIG. 11.

In the embodiment, the wave-like shape at the edge of the hole 75a is formed by distorting and deforming the linear shape. Alternatively, the wave-like shape at the edge of the hole 75a may be formed in a smooth curved shape.

As shown in FIG. 5, an end 75e on the side of a bottom 75d with a mountain-like section of the refrigerant retention plate 75 is placed on the upper end surface of the tube 21, and brazed to the inner wall surface 60b extending in the vertical direction of the bottom-side half member 60 of the upper tank 18b. This creates a valley-like retention portion 76 between the bottom 75d of the refrigerant retention plate 75 and the inner wall surface of the upper tank 18b.

In the embodiment, as shown in FIG. 11, a distance P between the wave-like apexes 75c of the hole 75a is set to the same distance between the tubes 21, and thus the apex 75c is superimposed over the inlet part 21a of the tube 21.

In the above-mentioned structure, refrigerant flow paths of the entire integrated unit 20 will be described below in more detail with reference to FIGS. 3, 4, and 12. FIG. 12 is a schematic perspective view showing the whole refrigerant flow paths in the integrated unit 20.

The refrigerant inlet 25 of the connection block 23 is branched into the main passage 25a and the branch passage 16. The refrigerant in the main passage 25a passes through the main passage side opening 64a of the intervening plate 64, and then is decompressed through the ejector 14 (the nozzle part 14a→the mixer 14c→the diffuser 14d). The low-pressure refrigerant decompressed flows into the right space 32 of the upper tank 15b of the first evaporator 15 via the upper space 69 of the right space 28 in the upper tank 18b, and via a plurality of communication holes 71 in the direction of the arrow “a”.

The refrigerant in the right space 32 moves downward in the tubes 21 positioned on the right side of the heat exchange core 15a in the direction of the arrow “b” to flow into the right side part of the lower tank 15c. Within the lower tank 15c, a partition plate is not provided, and thus the refrigerant moves from the right side of the lower tank 15c to the left side thereof in the direction of the arrow “c”.

The refrigerant on the left side of the lower tank 15c moves upward in the tubes 21 positioned on the left side of the heat exchange core 15a in the direction of the arrow “d” to flow into the left space 31 of the upper tank 15b. The refrigerant further flows to the refrigerant outlet 26 of the connection block 23 in the direction of the arrow “e”.

In contrast, the refrigerant on the branch passage 16 of the connection block 23 is first decompressed through the capillary tube 17a, and then the low-pressure refrigerant decompressed (liquid-vapor two-phase refrigerant) flows into the lower space 70 of the right space 28 of the upper tank 18b of the second evaporator 18 in the direction of the arrow “f”.

The refrigerant flowing into the lower space 70 moves downward in the tubes 21 positioned on the right side of the heat exchange core 18a in the direction of the arrow “g” to flow into the right side part of the lower tank 18c. Within the lower tank 18c, a right and left partition plate is not provided, and thus the refrigerant moves from the right side of the lower tank 18c to the left side thereof in the direction of an arrow “h”.

The refrigerant on the left side of the lower tank 18c moves upward in the tubes 21 positioned on the left side of the heat exchange core 18a in the direction of the arrow “i” to flow into the left space 27 of the upper tank 18b. Since the refrigerant suction port 14b of the ejector 14 is in communication with the left space 27, the refrigerant in the left space 27 is sucked from the refrigerant suction port 14b into the ejector 14.

The integrated unit 20 has the structure of the refrigerant passage as described above. Only the single refrigerant inlet 25 may be provided on the connection block 23, and only the single refrigerant outlet 26 may be provided on the connection block 23 in the integrated unit 20 as a whole.

Now, an operation of the first embodiment will be described. When the compressor 11 is driven by a vehicle engine, the high-temperature and high-pressure refrigerant compressed by and discharged from the compressor 11 flows into the radiator 12, where the high-temperature refrigerant is cooled and condensed by the outside air. The high-pressure refrigerant flowing from the radiator 12 flows into the liquid receiver 12a, within which the refrigerant is separated into liquid and vapor phases. The liquid refrigerant is derived from the liquid receiver 12a and passes through the expansion valve 13.

The expansion valve 13 adjusts the degree of opening of the valve (refrigerant flow rate) such that the superheat degree of the refrigerant at the outlet of the first evaporator 15 (i.e., sucked refrigerant by the compressor) becomes a predetermined value, and the high-pressure refrigerant is decompressed. The refrigerant having passed through the expansion valve 13 (middle pressure refrigerant) flows into one refrigerant inlet 25 provided in the connection block 23 of the integrated unit 20.

At that time, the refrigerant flow is divided into the refrigerant flow directed from the main passage 25a of the connection block 23 to the nozzle part 14a the ejector 14, and the refrigerant flow directed from the refrigerant branch passage 16 of the connection block 23 to the capillary tube 17a.

The refrigerant flow into the ejector 14 is decompressed and expanded by the nozzle part 14a. Thus, the pressure energy of the refrigerant is converted into the speed energy at the nozzle part 14a, and the refrigerant is ejected from the jet port of the nozzle part 14a at high speed. At this time, the pressure drop of the refrigerant sucks from the refrigerant suction port 14b, the refrigerant (vapor-phase refrigerant) having passed through the second evaporator 18 on the branch refrigerant passage 16.

The refrigerant ejected from the nozzle part 14a and the refrigerant sucked into the refrigerant suction port 14b are combined by the mixer 14c on the downstream side of the nozzle part 14a to flow into the diffuser 14d. In the diffuser 14d, the speed (expansion) energy of the refrigerant is converted into the pressure energy by enlarging the path area, resulting in increased pressure of the refrigerant.

The refrigerant flowing from the diffuser 14d of the ejector 14 flows through the refrigerant flow paths indicated by the arrows “a” to “e” in FIG. 12 in the first evaporator 15. During this time, in the heat exchange core 15a of the first evaporator 15, the low-temperature and low-pressure refrigerant absorbs heat from the blown air in the direction of an arrow “A” so as to be evaporated. The vapor-phase refrigerant evaporated is sucked from the single refrigerant outlet 26 into the compressor 11, and compressed again.

The refrigerant flow into the refrigerant branch passage 16 is decompressed by the capillary tube 17a to become a low-pressure refrigerant (liquid-vapor two-phase refrigerant). The low-pressure refrigerant flows through the refrigerant flow paths indicated by the arrows “f” to “i” of FIG. 12 in the second evaporator 18. During this time, in the heat exchange core 18a of the second evaporator 18, the low-temperature and low-pressure refrigerant absorbs heat from the blown air having passed through the first evaporator 15 to be evaporated. The vapor-phase refrigerant evaporated is sucked from the refrigerant suction port 14b into the ejector 14.

As mentioned above, according to the embodiment, the refrigerant on the downstream side of the diffuser 14d of the ejector 14 can be supplied to the first evaporator 15, and the refrigerant on the branch path 16 side can be supplied to the second evaporator 18 via a capillary tube (throttle) 17a, so that the first and second evaporators 15 and 18 can exhibit cooling effects at the same time. Thus, the cooled air by both the first and second evaporators 15 and 18 can be blown into a space to be cooled, thereby cooling the space to be cooled.

At that time, the refrigerant evaporation pressure of the first evaporator 15 is the pressure of the refrigerant which has been increased by the diffuser 14d. In contrast, since the outlet side of the second evaporator 18 is connected to the refrigerant suction port 14b of the ejector 14, the lowest pressure of the refrigerant which has been decompressed at the nozzle part 14a can act on the second evaporator 18.

Thus, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the second evaporator 18 can be lower than the refrigerant evaporation pressure (refrigerant evaporation temperature) of the first evaporator 15. With respect to the direction of the flow A of the blown air, the first evaporator 15 whose refrigerant evaporation temperature is high is disposed on the upstream side, and the second evaporator 18 whose refrigerant evaporation temperature is low is disposed on the downstream side. Both a difference between the refrigerant evaporation temperature of the first evaporator 15 and the temperature of the blown air, and a difference between the refrigerant evaporation temperature of the second evaporator 18 and the temperature of the blown air can be secured.

Thus, both cooling performances of the first and second evaporators 15 and 18 can be exhibited effectively. Thus, the cooling performance of the common space to be cooled can be improved effectively in the combination of the first and second evaporators 15 and 18. Furthermore, the effect of pressurization by the diffuser 14d increases the pressure of suction refrigerant of the compressor 11, thereby decreasing the driving power of the compressor 11.

The refrigerant flow rate on the second evaporator 18 side can be adjusted independently by the capillary tube (throttle) 17 without depending on the function of the ejector 14, and the refrigerant flow rate into the first evaporator 15 can be adjusted by a throttle characteristic of the ejector 14. Thus, the refrigerant flow rates into the first and second evaporators 15 and 18 can be adjusted readily, corresponding to the respective heat loads of the first and second evaporators 15 and 18.

For a small cycle heat load, the difference between high and low pressures in the cycle becomes small, and the input of the ejector 14 also becomes small. In the cycle as disclosed in JP-B2-3322263, the refrigerant flow rate passing through the second evaporator 18 depends on only the refrigerant suction ability of the ejector 14. This results in decreased input of the ejector 14, deterioration in the refrigerant suction ability of the ejector 14, and decrease in the refrigerant flow rate of the second evaporator 18 in order, making it difficult to secure the cooling performance of the second evaporator 18.

In contrast, in the embodiment, the refrigerant having passed through the expansion valve 13 is branched at the upstream part of the nozzle part 14a of the ejector 14, and the branched refrigerant is sucked into the refrigerant suction port 14b through the refrigerant branch passage 16, so that the refrigerant branch passage 16 is in a parallel connection relation to the ejector 14.

Thus, the refrigerant can be supplied to the refrigerant branch passage 16, using not only the refrigerant suction ability of the ejector 14, but also the refrigerant suction and discharge abilities of the compressor 11. This can reduce the degree of decrease in the refrigerant flow rate on the second evaporator side 18 as compared with in the cycle disclosed in the patent document 1, even in the occurrence of phenomena, including decrease in input of the ejector 14, and deterioration in the refrigerant suction ability of the ejector 14. Accordingly, even under the condition of the low heat load, the cooling performance of the second evaporator 18 can be secured readily.

In the ejector refrigerant cycle device 10 of the embodiment, the vapor-liquid two-phase refrigerant (middle-pressure refrigerant) having passed through the expansion valve 13 is divided into the refrigerant flow directed from the main passage 25a of the connection block 23 to the nozzle part 14a of the ejector 14, and the refrigerant flow directed from the refrigerant branch passage 16 of the connection block 23 to the capillary tube 17a.

Since the flow rate of the refrigerant (as indicated by the arrow “f”) flowing from the capillary tube 17a into the lower space 70 of the right space 28 of the upper tank 18b in the second evaporator 18 becomes small, the refrigerant may not reach readily the side away from the downstream side end 17d of the capillary tube 17a within the lower space 70 (the distribution tank).

As a result, distribution of the refrigerant to the plurality of tubes 21 in the lower space 70 (distribution tank) may become non-uniform, leading to the non-uniform temperature distribution of the cooled air by the second evaporator 18.

For this reason, in the embodiment, as indicated by the arrow “j” of FIG. 5, the liquid refrigerant among the liquid-vapor two-phase refrigerant flowing from the capillary tube 17a into the lower space 70 is temporarily stored in the valley-like retention portion 76 formed on the bottom 75d of the refrigerant retention plate 75. Then, a part of liquid refrigerant overflowing from the valley-like retention portion 76 falls from the holes 75a of the refrigerant retention plate 75 into the tubes 21.

Thus, the liquid refrigerant can be guided to the side away from the downstream side end 17d of the capillary tube 17a in the lower space 70 (distribution tank), so that the distribution of the refrigerant to the tubes 21 inserted into the lower space 70 can be made uniform. Thus, the temperature distribution of the cooled air by the second evaporator 18 can be made uniform.

Through detailed studies, the inventors have found out that when a flex angle θ of the mountain-like section of the refrigerant retention plate 75 (see FIG. 5) is set to a range from 30 degrees to 170 degrees, the retention and falling of the liquid refrigerant by the refrigerant retention plate 75 can be performed appropriately, thereby distributing the refrigerant to the plurality of tubes 21 more uniformly.

Also, through the detailed studies, the inventors have further found out that the linear edge of the hole 75a of the refrigerant retention plate 75 may create a relatively large droplet of the liquid refrigerant due to surface tension occurring at the edge of the hole 75a, which falls from the hole 75a to the tubes 21 or the like, thus reducing the effect of uniform distribution of the refrigerant.

Since in the embodiment, as shown in FIG. 11, the edge of the hole 75a of the refrigerant retention plate 75 which edge extends in the direction of lamination of the tubes 21 is in the wave-like shape, a relatively large droplet of the liquid refrigerant due to the surface tension can fall from the hole 75a before it grows a larger one.

That is, since the liquid refrigerant can fall from the hole 75a into the tube 21 side in the small droplet state, the effect of uniform distribution of the refrigerant can be exhibited well.

It should be noted that the liquid refrigerant stored in the retention portion 76 overflows and falls from the apex 75c positioned at the lowest position among the edges of the hole 75a. In the embodiment, as shown in FIG. 11, the distance P between the wave-like apexes 75c is set to the same distance between the tubes 21, whereby the wave-like apex 75c is superimposed over the inlet part 21a of the tube 21. That is, the wave-like apexes 75c are overlapped with the inlet parts 21a of the tubes 21, respectively. This allows the liquid refrigerant overflowing and falling from the apexes 75c to directly flow into the tubes 21, thereby enabling the liquid refrigerant to flow into the tubes 21 effectively.

FIGS. 13 to 15 show an example 1, to which the invention is applied to form a modified integrated unit 20 of the present embodiment. That is, the example 1 is a modified example of the above-described first embodiment. FIG. 13 is a schematic perspective view showing the entire structure of the integrated unit 20 in the example 1, FIG. 14 is a schematic cross-sectional view of an upper tank of the first and second evaporators 15 and 18 in the example 1, and FIG. 15 is a sectional view of the upper tank of the second evaporator 18 in the example 1.

In the example 1, the capillary tube 17a is disposed within the upper tank 18b. That is, the downstream side end 17d of the capillary tube 17a is opened within the right space 28 of the upper tank 18b, penetrating a support hole 24a of a second connection block 24, as shown in FIG. 14. In the example 1, the refrigerant retention plate 75 is not disposed in the right space 28.

The connection block 23 in the example 1 of FIG. 14 corresponds to an integrated body of the connection block 23 and the intervening plate 64 according to the above-described embodiment. In the example 1, the ejector inlet part 63 is not formed, and the ejector 14 is inserted from the refrigerant inlet 25 into the upper tank 18b of the second evaporator 18. Thus, in this example, the spacer 72 and the plug 73 of the embodiment are not necessary.

Instead of the ejector fixing plate 65 of the embodiment, the second connection block 24 is disposed in the center area of the upper tank 18b in the tank longitudinal direction. This second connection block 24 partitions the inside space of the upper tank 18b into left and right spaces.

Since the upper and lower partition plate 67 of the above-described embodiment is not provided in this example 1, the right space 28 inside the upper tank 18b of the second evaporator 18 serves as one space without being partitioned into the upper space 69 and the lower space 70.

Instead of the communication hole 71 of the embodiment, a communication hole 24c of the second connection block 24 is communicated with the right space 32 of the upper tank 15b of the first evaporator 15 via a through hole 33a of an intermediate wall 33 between both the upper tanks 15b and 18b.

Thus, the low-pressure refrigerant discharged from the diffuser 14d of the ejector 14 flows into the right space 32 of the upper tank 15b of the first evaporator 15 via the communication hole 24c of the second connection block 24 and the through hole 33a of the intermediate wall 33 in the direction of the arrow “a” in FIG. 14.

In this example 1, the refrigerant retention plate 75 described in the embodiment may be disposed in the right space 28. In this case, the refrigerant retention plate 75 can uniformly distribute the refrigerant flowing from the downstream side end 17d of the capillary tube 17a into the right space 28, to the plurality of tubes 21.

FIGS. 16 to 18 correspond to a modified example 2 of the above-described first embodiment. In the above-described embodiment, the capillary tube 17a is disposed between the branch passage 16 of the first connection block 23 of the integrated unit 20, and the inlet side of the second evaporator 18, and the refrigerant at the inlet of the second evaporator 18 is decompressed by the capillary tube 17a. In the example 2 shown in FIGS. 16 to 18, the capillary tube 17a is not employed as the decompression means of the second evaporator 18, and instead, a fixed throttle hole 17b, such as an orifice, for throttling a path area to a predetermined level is provided on the branch passage 16 of the first connection block 23, and together therewith, a connection pipe 160 whose passage diameter is larger than that of the capillary tube 17a is disposed at an arrangement position of the capillary tube 17a of the first embodiment.

The example 2 has the same refrigerant passages as those of the example 1 shown in FIGS. 13 to 15, except that the low-pressure refrigerant decompressed by the fixed throttle hole 17b formed on the branch passage 16 of the first connection block 23 is introduced into the right space 28 of the upper tank 18b of the second evaporator 18 through the connection pipe 160.

FIGS. 19 to 21 correspond to a modified example 3 of the above-described first embodiment. Although in the example 1 shown in FIGS. 13 to 15, the ejector 14 and the capillary tube 17a are in a common tank, that is, in the upper tank 18b of the second evaporator 18; in the example 3 shown in FIGS. 19 to 21, only the capillary tube 17a is disposed in the upper tank 18b of the second evaporator 18, while the ejector 14 is disposed in another dedicated tank 34.

Together with removing the ejector 14 from the upper tank 18b of the second evaporator 18, the second connection block 24 employed in the example 1 shown in FIGS. 13 to 15 is withdrawn. Instead, a partition plate 35 is disposed in a center area of the upper tank 18b in the longitudinal direction, and is adapted to partition the inside space of the upper tank 18b into the left and right spaces. The downstream side end 17d of the capillary tube 17a is adapted to penetrate the partition plate 35 so as to communicate with the right space 28 of the upper tank 18b.

The above-mentioned another tank 34 is disposed in the intermediate position between the upper tank 15b of the first evaporator 15 and the upper tank 18b of the second evaporator 18 as shown in FIG. 19. The tank 34 has a cylindrical shape extending in the longitudinal direction of both tanks 15b and 18b. In this example, another tank 34 is integrally formed with the upper tanks 15b and 18b.

The ejector 14 and the cylindrical another tank 34 extend up to the bottom (right side) away from the partition plates 30 and 35 for both tanks 15b and 18b, as shown in FIG. 20. The outlet part of the ejector 14 (outlet part of the diffuser 14d) communicates with the right space 32 of the upper tank 15b of the first evaporator 15 through the through hole (lateral hole) 34a, which penetrates the circumferential wall of the tank 34.

Similarly, the refrigerant inlet port 14b of the ejector 14 communicates with the left space 27 of the upper tank 18b of the second evaporator 18 through the through hole (lateral hole) 34b, which penetrates the circumferential wall of the tank 34.

Even in the example 3 shown in FIGS. 19 to 21, the low-pressure refrigerant (liquid-vapor two-phase refrigerant) flowing into the right space 28 of the downstream side end 17d of the capillary tube 17a would flow directly into the plurality of tubes 21 on the right side part of the heat exchange core 18a, which would lead to the non-uniform distribution of the liquid refrigerant to the plurality of tubes 21.

For this reason, in the example 3 shown in FIGS. 19 to 21, the refrigerant retention plate 75 described in the first embodiment may be located in the right space 28. In this case, the refrigerant retention plate 75 can uniformly distribute the refrigerant into the plurality of tubes 21 as is the case with the first embodiment.

An example 4 shown in FIGS. 22 to 24 is obtained by modifying the example 3 shown in FIGS. 19 to 21, wherein the capillary tube 17a of the example 3 shown in FIGS. 19 to 21 is withdrawn, and instead, the fixed throttle hole 17b and the connection pipe 160 in the example 2 are employed.

That is, in the example 4 shown in FIGS. 22 to 24, the fixed throttle hole 17b serving as the decompression unit is formed on the branch passage 16 of the first connection block 23, and the downstream side of the fixed throttle hole 17b communicates with the right space 28 of the upper tank 18b of the second evaporator 18 through the connection pipe 160.

Although in any one of the first embodiment and the examples 1 to 4, the ejector 14 is disposed in the upper tank 18b of the second evaporator 18, or in the other tank 34 adjacent to the upper tank 18b, in an example 5 shown in FIG. 25, the ejector 14 is disposed in an external cassette 36 (housing member) disposed outside of the first and second evaporators 15 and 18. FIG. 25 is a schematic view in which a part of the integrated unit is shown in cross section.

This cassette 36 is an external member which is attached to the outside of the first and second evaporators 15 and 18, and mainly includes the ejector 14, a lower case part 37 accommodating therein the ejector 14 part, and an upper case part 38.

The main body of the ejector 14 (i.e., the part in which the nozzle part 14a is built) is formed in a columnar shape extending vertically along the one side of each of the first and second evaporators 15 and 18 in an example shown in FIG. 25. The main body of the ejector 14 may be made of any one of metal, such as aluminum, and resin.

On the outer peripheral wall of the main body of the ejector 14, seal members S1 and S2 made of O rings are disposed. Note that the main body of the ejector 14 may be formed into another shape other than the columnar shape, such as a rectangular parallelepiped.

The lower case 37 is previously fixed onto the side ends of the first and second evaporators 15 and 18. More specifically, the lower case 37 is an oblong rectangular parallelepiped with its bottom closed and its upper surface opened. Note that the material for the lower case 37 may be any one of metal, such as aluminum, and resin. The lower case 37 is fixed to the sides of the first and second evaporators 15 and 18 with screwing means or the like.

The ejector body of the ejector 14 is inserted from an opening on the upper surface of the lower case 37 into the lower case 37. An upper part of the ejector 14, that is, an upper part (an inlet side part of the nozzle 14a) from the refrigerant suction port 14b of the ejector 14 is protruded above the lower case 37.

Then, the upper protruding part of the ejector 14 is fitted into the upper case 38, while the upper case 38 is placed as a cover on the opening on the upper surface of the lower case 37. The upper case 38 and the lower case 37 are integrally tightened up with the screwing means or other fastening member.

This can hold and fix the body of the ejector 14 within the lower case 37 and the upper case 38. Since in FIG. 25, the air flow direction A is opposite to that shown in FIG. 2, the first and second evaporators 15 and 18 in FIG. 25 are reversed laterally with respect to FIG. 2.

The upper case 38 is integrally formed with the first connection block 23 in the examples 1 to 4. That is, in the upper case 38, the refrigerant inlet 25 and the refrigerant outlet 26 are adjacent to each other and arranged in parallel. The refrigerant inlet 25 branches on a midstream of the passage, into the main passage 25a directed to the inlet side of the nozzle part 14a of the ejector 14, and the branch passage 16. The fixed throttle hole 17b serving as the decompression means is formed in the branch passage 16. The fixed throttle hole 17b of this example is the same as that in each of the comparative example 3 and the example 4.

The main passage 25a is flexed into a L shape from the direction of the passage of the refrigerant inlet 25 to extend in the longitudinal direction (vertical direction) of the ejector 14. In the main passage 25a, the nozzle 14a, the mixer 14c and the diffuser 14d of the ejector 14 are formed from the upper part to the lower part in this order.

The outlet part of the ejector 14 (outlet part of the diffuser 14d) is positioned near the other end (lower end) of the ejector 14 in the longitudinal direction. The outlet part of the ejector 14 is connected to one end of a connection pipe 39 via the communication hole 37a of the lower case 37. The other end of the connection pipe 39 is connected to the right space 32 of the upper tank 15b of the first evaporator 15.

The passage of the refrigerant outlet 26 of the upper case 38 is connected to the left space 31 of the upper tank 15b of the first evaporator 15.

The refrigerant suction port 14b of the ejector 14 is formed to penetrate the wall of the main body of the ejector 14 in the radial direction, and communicates with the downstream part of the nozzle part 14a of the ejector 14. The refrigerant suction port 14b is connected to one end of a connection pipe 40 via a communication hole 38a of the upper case 38, and the other end of the connection pipe 40 is connected to the left space 27 of the upper tank 18b of the second evaporator 18.

The outlet side of the fixed throttle hole 17b of the branch passage 16 is connected to the right space 28 of the upper tank 18b of the second evaporator 18 via the connection pipe 41.

By connecting the passage of the external cassette 36 with the four left and right spaces 27, 28, 31, and 32 of the upper tanks 15b and 18b of the first and second evaporators 15 and 18 as described above, the refrigerant having passed through the ejector 14 flows through the flow path of the first evaporator 15 indicated by the arrows “a” to “e” after passing through the connection pipe 39, and then flows from the refrigerant outlet 26 of the external cassette 36 into the external flow path (the suction side of the compressor), as shown in FIG. 25.

The refrigerant branched into the branch passage 16 at the refrigerant inlet 25 and decompressed by the fixed throttle hole 17b flows through the flow path of the second evaporator 18 indicated by the arrows “f” to “i” after passing through the connection pipe 41, and reaches the left space 27 of the upper tank 18b. The refrigerant is sucked into the refrigerant suction port 14b of the ejector 14 from the left space 27 via the connection pipe 40.

Although in the example 5 of FIG. 25, a part corresponding to the first connection block 23 is integrally formed with the upper case part 38 of the external cassette 36, in an example 6 of FIG. 26, the first connection block 23 is separated from the external cassette 36, and is used as an independent component.

In the example 6 of FIG. 26, in one (e.g., right side) of both the left and right sides of the first and second evaporators 15 and 18, the first connection block 23 is disposed, and on the other side, the external cassette 36 is disposed.

The external cassette 36 has such a structure to hold and fix the ejector 14 part in the lower case 37 and the upper case 38 in the same way as the example 5 of FIG. 25. Note that in the example 6 of FIG. 26, not the lower case 37, but the upper case 38 is previously fixed to one side of the first and second evaporators 15 and 18.

In the example 6 of FIG. 26, the ejector 14 is inserted from a lower opening of the upper case 38 into the upper case 38, and then the lower case 37 is placed as a cover over the lower opening of the upper case 38. Both the upper and lower cases 37 and 38 are integrally tightened up with the screwing means or the like.

In this example, the direction of assembly of the ejector 14 is opposite to that in the example 5 of FIG. 25. The ejector 14 is assembled such that the nozzle part 14a (inlet side) is placed in the lower position, while the diffuser 14d (outlet side) is placed in the upper position.

The refrigerant suction port 14b of the ejector 14 is connected to the left side of the lower tank 18c of the second evaporator 18 via a communication hole 37b of the lower case 37. The diffuser 14d is connected to the left space 31 of the upper tank 15b of the first evaporator 15 via a communication 38b of the upper case 38.

On the other hand, the refrigerant inlet 25 of the first connection block 23 branches into the main passage 25a and the branch passage 16. The main passage 25a is connected to the communication hole 37c of the lower case 37 of the external cassette 36 through the connection pipe 42. The communication hole 37c communicates with an inlet part 43 of the nozzle part 14a of the ejector 14.

The branch passage 16 is connected to the right side of the lower tank 18c of the second evaporator 18 via the capillary tube 17a serving as the decompression means.

In the second evaporator 18 of the example 6 of FIG. 26, the partition plate 35 of the upper tank 18b described above is deleted, and instead, another partition plate 35a is disposed in the center area of the lower tank 18c in the longitudinal (lateral) direction. This partition plate 35a is adapted to partition the inside space of the lower tank 18c into the left and right spaces.

Thus, the low-pressure refrigerant having passed through the capillary tube 17a passes through the refrigerant flow path indicated by the arrows “f” to “i” of the second evaporator 18, and then is sucked into the refrigerant suction port 14b of the ejector 14 from the left side of the lower tank 18c via the communication hole 37b.

The refrigerant in the main passage 25a of the refrigerant inlet 25 passes through the connection pipe 42, flows into the inlet 43 of the ejector 14 of the external cassette 36 via the communication hole 37c, and is decompressed and expanded by the nozzle part 14a. The low-pressure refrigerant from the outlet of the ejector 14 flows into the left space 31 of the upper tank 15b of the first evaporator 15 via the communication hole 38b of the upper case 38.

Thereafter, the low-pressure refrigerant flows through the refrigerant flow path indicated by the arrows “a” to “d” of the first evaporator 15 toward the refrigerant outlet 26 of the first connection block 23.

In the above-described examples 1 to 6, the other parts can be made similar to the corresponding parts indicated by the same reference parts of the above-described first embodiment, and detail description thereof is omitted.

Second Embodiment

In the above-described first embodiment, the edge of the hole 75a of the refrigerant retention plate 75, which extends in the direction of lamination of the tubes 21, is formed in the wave-like shape. However, in the second embodiment, as shown in FIGS. 27 and 28, an edge of the hole 75a of the refrigerant retention plate 75, which extends in the direction of lamination of the tubes 21, is formed linearly, and the hole 75a itself is formed in a rectangular shape extending in the lamination direction of the tubes 21.

Also, in the second embodiment, the liquid refrigerant among the liquid-vapor two-phase refrigerant flowing from the capillary tube 17a into the lower space 70 is temporarily stored in the retention portion 76, and some liquid refrigerant overflowing from the retention portion 76 falls from the holes 75a of the refrigerant retention plate 75 into the tubes 21. This enables the uniform distribution of the liquid refrigerant to the plurality of tubes 21. In the second embodiment, the other parts can be made similar to those of the above-described first embodiment.

In addition, the structure of the refrigerant retention plate 75 of the second embodiment can be used for any one of the modified examples 1 to 6 of the first embodiment.

Third Embodiment

In the above-described second embodiment, the hole 75a of the refrigerant retention plate 75 is formed approximately in a rectangular shape extending in the lamination direction of the tubes 21. However, in the third embodiment, as shown in FIGS. 29 and 30, the hole 75a of the refrigerant retention plate 75 is formed in an elliptic shape extending in the direction of lamination of the tubes 21.

Also, in the third embodiment, the liquid refrigerant among the liquid-vapor two-phase refrigerant flowing from the capillary tube 17a into the lower space 70 is temporarily stored in the retention portion 76, and some liquid refrigerant overflowing from the retention portion 76 falls from the holes 75a of the refrigerant retention plate 75 into the tubes 21. This enables the uniform distribution of the liquid refrigerant to the plurality of tubes 21.

In the third embodiment, the other parts can be made similar to those of the above-described first embodiment. In addition, the structure of the refrigerant retention plate 75 of the third embodiment can be used for any one of the modified examples 1 to 6 of the first embodiment.

Fourth Embodiment

In the third embodiment, each hole 75a of the refrigerant retention plate 75 is overlapped with the inlet parts 21a of the plural tubes 21. However, in the fourth embodiment, as shown in FIG. 31, each hole 75a of the refrigerant retention plate 75 is superimposed over only the inlet part 21a of one tube 21. That is, one hole 75a of the refrigerant retention plate 75 is overlapped with only the inlet part 21a of one tube 21.

In the fourth embodiment, the diameter of the hole 75a in the longitudinal direction of the tube 21 is decreased as compared with the third embodiment, and instead, the number of the holes 75a is increased.

More specifically, the distance between the holes 75a is identical to that between the tubes 21, and each hole 75a is positioned above the inlet part 21a of the tube 21.

In the fourth embodiment, the liquid refrigerant which overflows from the retention portion 76 to fall into the tube 21 side from the holes 75a can flow directly into the tubes 21.

Thus, the distribution of the liquid refrigerant to the plurality of tubes 21 can be rendered uniform effectively. In the fourth embodiment, the other parts can be made similar to those of the above-described first embodiment.

In addition, the structure of the refrigerant retention plate 75 of the fourth embodiment can be used for any one of the modified examples 1 to 6 of the first embodiment.

Fifth Embodiment

In the respective embodiments described above, the refrigerant retention plate 75 is formed to have the mountain-like section, in the bottom 75d of which the retention portion 76 is formed. However, in the fifth embodiment, as shown in FIG. 32, a recess part 77a with a U-shaped section is formed in a refrigerant retention plate 77, and the recess part 77a forms the retention part 78.

As shown in FIG. 32, the refrigerant retention plate 77 has a flat surface part 77b formed and extending from both ends of the recess part 77a with the U-shaped section toward the inner wall surface 60b extending in the vertical direction of the bottom-side half member 60 of the upper tank 18b. A tip end surface 77c of the flat surface part 77b is abutted against the inner wall surface 60b of the bottom-side half member 60.

A notch 77d directed toward the inner wall surface 60b of the bottom-side half member 60 is formed in the flat surface part 77b. A space enclosed by the notch 77d and the inner wall surface 60b of the bottom-side half member 60 forms a hole 79 for allowing the liquid refrigerant temporarily stored in the retention portion 78 of the recess part 77a to fall into the tube 21 side.

In the sixth embodiment, the liquid refrigerant among the liquid-vapor two-phase refrigerant flowing from the capillary tube 17a into the lower space 70 is temporarily stored in the retention portion 78 of the refrigerant retention plate 77, and some liquid refrigerant overflowing from the retention portion 78 falls from the hole 79 into the tube 21 side as indicated by an arrow “k”.

This enables the uniform distribution of the liquid refrigerant to the plurality of tubes 21 in the same way as the embodiments described above.

In the fifth embodiment, the other parts can be made similar to those of the above-described first embodiment. In addition, the retention portion 78 of the refrigerant retention plate 77 of the fifth embodiment can be used for any one of the modified examples 1 to 6 of the first embodiment.

Sixth Embodiment

In the above-mentioned first to fourth embodiments and its modified examples 1 to 6, the refrigerant retention plate 75 has the mountain-like section, on the bottom 75d of which the retention portion 76 is formed. However, in the sixth embodiment, as shown in FIG. 33, a refrigerant retention plate 80 is formed in a flat plate shape having a slant section, and on the lower side of the slant of the refrigerant retention plate 80, a retention portion 81 is formed.

As shown in FIG. 33, two ends 80a of the section of the refrigerant retention plate 80 are abutted against the inner wall surface 60b of the bottom-side half member 60. Thus, the slant lower side of the refrigerant retention plate 80 and the inner wall surface 60b of the bottom-side half member 60 form the retention portion 81 for temporarily storing therein the liquid refrigerant.

On the slant upper side of the refrigerant retention plate 80, a notch 80b is formed which is directed toward the inner wall surface 60b of the bottom-side half member 60. A space enclosed by the notch 80b and the inner wall surface 60b of the bottom-side half member 60 forms a hole 82 for allowing the liquid refrigerant temporarily stored in the retention portion 81 to fall into the tube 21 side.

In the sixth embodiment, the liquid refrigerant among the liquid-vapor two-phase refrigerant flowing from the capillary tube 17a into the lower space 70 is temporarily stored in the retention portion 81, and some liquid refrigerant overflowing from the retention portion 81 falls from the hole 82 to the tube 21 side as indicated by the arrow “m” of FIG. 33.

This enables the uniform distribution of the liquid refrigerant to the plurality of tubes 21 as is the case with the embodiments described above.

In the sixth embodiment, the other parts can be made similar to those of the above-described first embodiment. In addition, the structure of the refrigerant retention plate 80 of the sixth embodiment can be used for any one of the modified examples 1 to 6 of the first embodiment.

Seventh Embodiment

In the first embodiment, the expansion valve type cycle including the liquid receiver 12a on the outlet side of the radiator 12, and the expansion valve 13 disposed on the outlet side of the liquid receiver 12a is employed. However, in a seventh embodiment, as shown in FIG. 34, an accumulator 50 is provided which serves as a liquid-vapor separator for separating the refrigerant into liquid and vapor phases on the outlet side of the first evaporator 15, and for storing the excessive refrigerant in the form of liquid. The vapor-phase refrigerant is derived from the accumulator 50 into the suction side of the compressor 11.

In the accumulator cycle of the FIG. 34, a liquid-vapor interface between the vapor-phase refrigerant and the liquid-phase refrigerant in the accumulator 50 is formed, and hence it is not necessary to control the superheat degree of the refrigerant at the outlet of the first evaporator 15 by the expansion valve 13 like the first embodiment.

Since the liquid receiver 12a and the expansion valve 13 are deleted from the accumulator cycle, the refrigerant inlet 25 of the integrated unit 20 may be directly connected to the outlet side of the radiator 12. The refrigerant outlet 26 of the integrated unit 20 may be connected to the inlet side of the accumulator 50, and the outlet side of the accumulator 50 may be directly connected to the suction side of the compressor 11.

In the seventh embodiment, any one structure of the refrigerant retention plates 75, 77, 80 described above can be used for the integrated unit 20 of the refrigerant cycle (accumulator cycle) of FIG. 34.

Eighth Embodiment

The eighth embodiment is a modified one from the seventh embodiment. As shown in FIG. 35, the accumulator 50 is integrally incorporated into the integrated unit 20 as one element. The outlet part of the accumulator 50 constitutes the refrigerant outlet 26 of the entire integrated unit 20. In the eighth embodiment, the other parts can be made similarly to the above described seventh embodiment.

Ninth Embodiment

In any one of the above-described first to eighth embodiments, the branch passage 16 branching on the inlet side of the ejector 14 is connected to the refrigerant suction port 14b of the ejector 14, and the throttle 17 and the second evaporator 18 are disposed on the branch passage 16. However, in the ninth embodiment, as shown in FIG. 36, the accumulator 50 serving as the liquid-vapor separator is disposed at the outlet side of the first evaporator 15, the branch passage 16 is provided for connecting the liquid-phase refrigerant outlet part 50a of the accumulator 50 to the refrigerant suction port 14b of the ejector 14, and the throttle 17 and the second evaporator 18 are disposed in the branch passage 16.

In the ninth embodiment, the ejector 14, the first and second evaporators 15 and 18, the throttle 17, and the accumulator 50 constitute an integrated unit 20. In the entire integrated unit 20, one refrigerant inlet 25 is provided at the inlet of the ejector 14, which is connected to the outlet of the radiator 12.

In the entire integrated unit 20, one refrigerant outlet 26 is provided at the vapor-phase refrigerant outlet of the accumulator 50, and connected to the suction side of the compressor 11.

In the ninth embodiment, any one structure of the refrigerant retention plates 75, 77, 80 described above can be used for the integrated unit 20 of the refrigerant cycle of FIG. 36.

Tenth Embodiment

In any one of the first to ninth embodiments includes the first evaporator 15 connected to the outlet side of the ejector 14, and the second evaporator 18 connected to the refrigerant suction port 14b of the ejector 14. However, in the tenth embodiment, as shown in FIG. 37, an integrated unit 20 is constituted in the ejector refrigerant cycle device 10 including only one evaporator 18 connected to the refrigerant suction port 14b of the ejector 14.

The integrated unit 20 of the tenth embodiment is constructed with the ejector 14, the evaporator 18, the throttle 17, and the accumulator 50. The integrated unit as the entire unit has one refrigerant inlet 25 and one refrigerant outlet 26. That is, the tenth embodiment corresponds to the unit of the ninth embodiment in which the first evaporator 15 is not provided.

Even in the tenth embodiment, any one structure of the refrigerant retention plates 75, 77, 80 described above can be used for the integrated unit 20 of the ejector refrigerant cycle device 10 of FIG. 37.

Eleventh Embodiment

In any one of the above-described first to ninth embodiments, the throttle 17 is incorporated in the integrated unit 20. However, in the eleventh embodiment, as shown in FIG. 38, the integrated unit 20 is constructed with the first and second evaporators 15 and 18 and the ejector 14, and the throttle 17 is independently provided separately from the integrated unit 20.

Also, in the eleventh embodiment, neither on the high-pressure side nor the low-pressure side of the cycle, the liquid-vapor separator is disposed, as shown in FIG. 38.

Twelfth Embodiment

FIG. 39 illustrates the twelfth embodiment, in which the accumulator 50 serving as the liquid-vapor separator is provided on the outlet side of the first evaporator 15 with respect to the eleventh embodiment, and is integrally incorporated in the integrated unit 20. That is, in the twelfth embodiment, the ejector 14, the first and second evaporators 15 and 18, and the accumulator 50 constitute the integrated unit 20, and the throttle 17 is independently provided separately from the integrated unit 20.

In the twelfth embodiment, any one structure of the refrigerant retention plates 75, 77, 80 described above can be used for the integrated unit 20 of the ejector refrigerant cycle device of FIG. 39.

Other Embodiments

It should be understood that the invention is not limited to the above-mentioned embodiments, and various modifications can be made to the embodiments as follows.

(1) In the first embodiment, in integrally assembling each component of the integrated unit 20, the components other than the ejector 14, that is, the first evaporator 15, the second evaporator 18, the connection block 23, the capillary tube 17a, and the like are brazed integrally with each other. The integral assembly of these components can also be performed by various fixing means other than brazing, including screwing, caulking, welding, adhesion, and the like.

Although in the first embodiment, the exemplary fixing means of the ejector 14 is the screwing, any fixing means other than the screwing can be used as long as the fixing means may not cause thermal deformation. More specifically, the fixing means, such as caulking, or adhesion, may be used to fix the ejector 14.

(2) Although in the above-mentioned respective embodiments, the vapor-compression subcritical refrigerant cycle has been described in which the refrigerant is a flon-based one, an HC-based one, or the like, whose high pressure does not exceed the critical pressure, the invention may be applied to a vapor-compression supercritical refrigerant cycle which employs the refrigerant, such as carbon dioxide (CO₂), whose high pressure exceeds the critical pressure.

Note that in the supercritical cycle, only the refrigerant discharged by the compressor dissipates heat in the supercritical state at the radiator 12, and hence is not condensed. Thus, the liquid receiver 12a disposed on the high-pressure side cannot exhibit a liquid-vapor separation effect of the refrigerant, and a retention effect of the excessive liquid refrigerant. As shown in FIGS. 34 to 39, the supercritical cycle may have the structure including the accumulator 50 at the outlet of the first evaporator 15 for serving as the low-pressure liquid-vapor separator.

(3) Although in the above-mentioned embodiments, the throttle 17 is constructed by the fixed throttle hole 17b, such as the capillary tube 17a or the orifice, the throttle 17 may be constructed by an electric control valve whose valve opening (in which an opening degree of a passage restriction) is adjustable by the electric actuator. The throttle 17 may be composed of a combination of the fixed throttle, such as the capillary tube 17a, and the fixed throttle hole 17b, and an electromagnetic valve.

(4) Although in the above-mentioned respective embodiments, the exemplary ejector 14 is a fixed ejector having the nozzle part 14a with the certain path area, the ejector 14 for use may be a variable ejector having a variable nozzle part whose path area is adjustable.

For example, the variable nozzle part may be a mechanism which is designed to adjust the path area by controlling the position of a needle inserted into a passage of the variable nozzle part using the electric actuator.

(5) Although in the first embodiment and the like, the invention is applied to the refrigeration cycle device adapted for cooling the interior of the vehicle and for the freezer and refrigerator, both the first evaporator 15 whose refrigeration evaporation temperature is high and the second evaporator 18 whose refrigeration evaporation temperature is low may be used for cooling different areas inside the compartment of the vehicle (for example, an area on a front seat side inside the compartment of the vehicle, and an area on a back seat side therein).

Alternatively or additionally, both the first evaporator 15 whose refrigeration evaporation temperature is high and the second evaporator 18 whose refrigeration evaporation temperature is low may be used for cooling the freezer and refrigerator. That is, a refrigeration chamber of the freezer and refrigerator may be cooled by the first evaporator 15 whose refrigeration evaporation temperature is high, while a freezing chamber of the freezer and refrigerator may be cooled by the second evaporator 18 whose refrigeration evaporation temperature is low.

(6) Although in the first embodiment and the like, the thermal expansion valve 13 and the temperature sensing part 13a are separately provided from the unit for the ejector refrigerant cycle device, the thermal expansion valve 13 and the temperature sensing part 13a may be integrally incorporated in the unit for the ejector refrigerant cycle device. For example, a mechanism for accommodating the thermal expansion valve 13 and the temperature sensing part 13a in the connection block 23 of the integrated unit 20 can be employed. In this case, the refrigerant inlet 25 is positioned between the liquid receiver 12a and the thermal expansion valve 13, and the refrigerant outlet 26 is positioned between the compressor 11 and a passage part on which the temperature sensing part 13a is installed.

(7) It is apparent that although in the above-mentioned respective embodiments, the refrigeration cycle device for the vehicle has been described, the invention can be applied not only to the vehicle, but also to a fixed refrigeration cycle or the like in the same way.

(8) Although in the above-described first embodiment, the downstream side end 17d of the capillary tube 17a is inserted horizontally into the upper tank 18b, the downstream side end 17d of the capillary tube 17a may be inserted vertically into the upper tank 18b.

(9) In the above-mentioned respective embodiments, the tanks 15b, 15c, 18b, and 18c of the first evaporator 15 and the second evaporator 18 are disposed on both the upper and lower sides of the first evaporator 15, that is, the first evaporator 15 and the second evaporator 18 are disposed vertically. Alternatively, the first evaporator 15 and the second evaporator 18 may be disposed in a slanted manner with respect to the vertical direction.

In this case, if the refrigerant retention plates 75, 77, and 80 were slanted together with the first and second evaporators 15 and 18, then the liquid refrigerant would intend to overflow from the retention portions 76, 78, and 81, resulting in decreased effect of storing the liquid refrigerant. Thus, the refrigerant retention plates 75, 77, and 80 are not slanted, and may preferably be arranged at the same angle as in the above-mentioned respective embodiments.

(10) Although in the above-mentioned respective embodiments, the invention is applied to the evaporator 18 serving as the heat exchanger on the heat absorbing side of the refrigeration cycle, the invention can also be applied to various applications of heat exchangers.

For example, the invention may be applied to a condenser or the like serving as the heat exchanger on the heat radiation side of the refrigeration cycle. Also, the invention may be applied to the heat exchanger through which the hot water passes on the inside passage (the fluid passage corresponding to the tube 21 in each embodiment described above), such as a hot water radiator for heating, or a radiator for engine cooling.

The invention can also be applied to the heat exchanger through which oil or the like passes on the inside passage, such as an engine oil cooler, or the heat exchanger or the like through which cold water flows on the inside passage in the same way.

Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.

Claims

1. A heat exchanger comprising:

a plurality of tubes defining fluid passages through which a heat-exchanger fluid including at least a liquid-phase fluid passes;

a tank disposed above an inlet part of the plurality of fluid passages for distributing a flow of the heat-exchanger fluid to the fluid passages; and

a retention member, located above the inlet part within the tank, for temporarily storing therein the liquid-phase fluid flowing into the tank,

wherein the retention member is constructed such that the liquid-phase fluid overflowing from the retention member falls toward the inlet part.

2. The heat exchanger according to claim 1,

wherein the retention member has a mountain section protruding from a horizontal surface,

wherein the mountain section and an inner wall surface of the tank extending in a vertical direction define a recessed retention portion in which the liquid-phase fluid is temporarily stored, and

wherein the mountain section of the retention member includes an apex area having a hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing.

3. The heat exchanger according to claim 2, wherein a flexed angle (θ) of the mountain section is in a range from 30 degrees to 170 degrees.

4. The heat exchanger according to claim 2, wherein the hole is provided in the mountain section to be superimposed over the inlet part.

5. The heat exchanger according to claim 2, wherein an edge of the hole is formed in a wave shape.

6. The heat exchanger according to claim 2,

wherein an edge of the hole is formed in a wave shape, and

wherein an apex of the wave shape recessed toward an outside of the hole is superimposed over the inlet part.

7. The heat exchanger according to claim 1,

wherein the retention member includes a tilt plate tilted in the tank with respective to a horizontal direction, and

wherein the tilt plate has: a lower part, which forms a retention portion in which the liquid-phase fluid is temporarily stored, together with an inner wall surface of the tank; and an upper part having a hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing.

8. The heat exchanger according to claim 1,

wherein the retention member includes a plate member having a recessed part for defining a retention portion in which the liquid-phase fluid is temporarily stored, and

wherein the plate member is separated from an inner wall of the tank to form a hole through which the liquid-phase fluid stored in the retention portion falls toward the inlet part due to the overflowing.

9. The heat exchanger according to claim 1,

wherein the retention member has a plurality of holes each of which overlaps with at least one of the inlet parts of the tubes.

10. A refrigerant cycle device comprising

a compressor for compressing refrigerant;

a radiator for cooling the refrigerant from the compressor;

an ejector which has a nozzle part for decompressing the refrigerant from the radiator, and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from a jet port of the nozzle part;

a one evaporator in which the refrigerant to be drawn into the refrigerant suction port is evaporated, wherein the one evaporator includes a plurality of tubes defining refrigerant passages through which refrigerant including at least a liquid-phase refrigerant passes, and a tank disposed above an inlet part of the plurality of refrigerant passages for distributing a flow of the refrigerant to the refrigerant passages; and

a retention member, located in the tank above the inlet part, for temporarily storing therein the liquid-phase refrigerant flowing into the tank,

wherein the retention member is provided to form a hole through which the liquid-phase refrigerant overflowing from the retention member falls toward the inlet part.

11. The refrigerant cycle device according to claim 10, further comprising

another evaporator for evaporating refrigerant,

wherein the another evaporator includes a refrigerant inlet coupled to a refrigerant outlet of the ejector and a refrigerant outlet coupled to a refrigerant suction side of the compressor, and

wherein the one evaporator and the another evaporator are integrated with the ejector.

12. The refrigerant cycle device according to claim 10, wherein the ejector is integrated with at least the one evaporator.

13. The refrigerant cycle device according to claim 12, wherein the ejector is located in the tank of the one evaporator.

14. The refrigerant cycle device according to claim 12, wherein the ejector is integrated with the one evaporator outside of the one evaporator.

15. The refrigerant cycle device according to claim 10, further comprising

a decompression member, integrated with the one evaporator, for decompressing the refrigerant flowing into the one evaporator.

16. The refrigerant cycle device according to claim 10, further comprising

a gas-liquid separator, integrated with the one evaporator, for separating the refrigerant after passing through the tubes of the one evaporator into gas-phase refrigerant and the liquid-phase refrigerant.

17. The refrigerant cycle device according to claim 10,

wherein the retention member has a mountain section protruding from a horizontal surface,

wherein the mountain section and an inner wall surface of the tank extending in a vertical direction define a recessed retention portion in which the liquid-phase refrigerant is temporarily stored, and

wherein the mountain section of the retention member includes an apex area having the hole through which the liquid-phase refrigerant stored in the retention portion falls toward the inlet part due to the overflowing.

18. The refrigerant cycle device according to claim 10,

wherein the retention member includes a tilt plate tilted in the tank with respective to a horizontal direction, and

wherein the tilt plate has: a lower part, which forms a retention portion in which the liquid-phase refrigerant is temporarily stored, together with an inner wall surface of the tank; and an upper part having the hole through which the liquid-phase refrigerant stored in the retention portion falls toward the inlet part due to the overflowing.

19. The refrigerant cycle device according to claim 10,

wherein the retention member includes a plate member having a recessed part for defining a retention portion in which the liquid-phase refrigerant is temporarily stored, and

wherein the plate member is separated from an inner wall of the tank to form the hole through which the liquid-phase refrigerant stored in the retention portion falls toward the inlet part due to the overflowing.

20. The refrigerant cycle device according to claim 15, wherein the decompression member and the ejector are integrated with the one evaporator.