Heat exchanger and producing method thereof

Abstract

A heat exchanger and a production method thereof are disclosed. A through hole (17) is formed in a second header member (17) of a first refrigerant header tank (14) of segmentation type. A protrusion (20a) of a first connector (20) for pipe connection is deformed by being inserted into the through hole (17b) and thus tacked by engagement. Under this condition, the first header member (16) is fitted and tacked on the second header member (17) so that the first connector (20), the second head member (17) and the first head member (16) are integrally brazed and coupled. By doing so, the first connector (20) can be properly coupled to the first refrigerant header tank (14). Further, the first connector (20) can be tacked by engagement before the first refrigerant header tank (14) assumes a cylindrical shape, and therefore the workability of tacking the first connector (20) is improved.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a heat exchanger having connectors for connecting pipes through which a heat-exchanging fluid flows in and out, and a method of producing the heat exchanger.

2. Description of the Related Art

Japanese Unexamined Patent Publication No. 2004-108638 (Patent Document 1) discloses a heat exchanger used as a condenser for condensing by radiating the heat of the refrigerant into the air. This conventional heat exchanger includes a pair of header tanks of a segmentation type on one of which the connectors are mounted. The header tank of segmentation type is defined as a cylindrical header tank with a second header member fitted on a first header member connected to the tubes in which the heat-exchanging fluid flows.

The method of mounting the connectors on the header tank of the heat exchanger according to Patent Document 1 is explained below. First, the first and second header members of the heat exchanger disclosed in Patent Document 1 have notches, respectively, formed in the fitting portions thereof fitted with each other, and by fitting the first and second header members on each other, a rectangular through hole is formed by the notches.

The connectors, on the other hand, are each formed with a protrusion adapted to the shape of and insertable into the corresponding through hole. By inserting the protrusions into the through holes and further caulking the protrusions on the inner periphery of the through holes, the connectors are tacked on the header tank. With the connectors tacked on the header tank, the first and second header members and the connectors are brazed to each other thereby to mount the connectors on the header tank.

In the heat exchanger disclosed in Patent Document 1, the through holes for tacking the connectors are formed by combining the notches formed on the first and second header members. Once the relative positions of the notches are shifted by the dimensional error or assembly error in the manufacture of the first and second header members, therefore, the shape of each through hole fails to fit the shape of the protrusion of each connector.

In the case where the shape of the connector protrusions and the shape of the through holes fail to coincide with each other, a sufficient tacking strength of the connectors tacked and caulked on the header tank cannot be obtained. As a result, at the time of coupling by brazing, the tacked state between the connectors and the header tanks cannot be maintained, and the dimensional accuracy and the coupling strength of the connectors mounted on and coupled to the header tank are adversely affected, thereby making it impossible to properly couple the connectors to the header tank.

SUMMARY OF THE INVENTION

In view of this situation, the object of this invention is to couple the connectors properly to the header tank.

In order to achieve the aforementioned object, according to a first aspect of the invention, there is provided a heat exchanger comprising a cylindrical header tank (14) connected with a plurality of tubes (11) through which a fluid passes and a pair of connectors (20, 21) for fluid pipe connection, wherein the connectors (20, 21) have a tacked portion (20b) engaging the header tank (14), and the connectors (20, 21) and the header tank (14) have coupling surfaces, respectively, coupled by brazing to each other.

In this aspect, the connectors (20, 21) have the tacked portion (20b) engaging the header tank (14), and therefore, the connectors (20, 21) can be coupled to and tacked on the header tank (14) positively.

As a result, the reduction in the accuracy of the mounting dimensions and the coupling strength of the connectors (20, 21) to the header tank (14) after coupling can be suppressed and the connectors (20, 21) can be coupled properly to the header tank (14).

Further, the connectors (20, 21) and the header tank (14) each have a coupling surface, and therefore a sufficient coupling strength can be secured between them.

In the heat exchanger according to the first aspect described above, the header tank (14) has a through hole (17b) establishing communication between inside and outside of the header tank (14), and the connectors (20, 21) each have the protrusion (20b) inserted into the through hole (17b). The tacked portion, therefore, may be engaging portions (20g) configured by deforming the protrusion (20b).

In this case, the protrusion (20b) inserted into the through hole (17b) is deformed and makes up the engaging portions (20g). Therefore, the connectors (20, 21) can be easily tacked on the header tank (14). Further, as compared with the case in which the engaging portion (20b) is formed on the outer peripheral surface of the header tank (14), the header tank (14) is not unnecessarily made bulky.

Thus, the connectors (20, 21) can be properly connected to the header tank (14) without increasing the size of the heat exchanger.

Also, in the heat exchanger according to the first aspect having the through hole (17b), the protrusion (20b) may be caulked on the inner periphery of the through hole (17b). Then, since the protrusion (20) is caulked on the through hole (17b), the connectors (20, 21) can be tacked more strongly on the header tank (14).

Further, in the heat exchanger according to the first aspect described above, the through hole (17b) may alternatively be formed on the side of the cylinder of the header tank (14). Also, the opening of the through hole (17b) may be elongated along the length of the header tank (14). Furthermore, the engaging portions (20g) may be arranged at the two ends of the protrusion (20) along the length of the header tank (14).

Generally, the cylindrical header tank (14) is elongated. In the case where each engaging portion (20g) is deformed toward the inner periphery of the through hole (17b) with a load imposed in the direction parallel to the longitudinal direction, the deformation of the through hole (17b) can be suppressed more than in the case where the deforming load is imposed in the other directions.

Specifically, as shown in FIG. 5 for explaining an embodiment described later, the protrusion (20b) is deformed toward the inner periphery of the through hole (17b) while being caulked by the load in the directions of arrows E providing the load along the circumference of the header tank (14). Then, the through hole (17b) is easily extended and deformed along the outer periphery of the header tank (14).

In the case where the protrusion (20b) is caulked by the load along the direction of arrow F parallel to the length of the header tank (14), on the other hand, the header tank (14) is not easily deformed in longitudinal direction and therefore the deformation of the through hole (17b) can be suppressed.

By arranging the engaging portion (20g) at each longitudinal end of the inner periphery of the through hole (17b) along the length of the header tank (14), therefore, the protrusion (20b) can be deformed under the load parallel to the length of the header tank (14). Thus, the deformation of the through hole (17b) is suppressed, and the connectors (20, 21) can be more properly coupled to the header tank (14).

In the heat exchanger according to the first aspect having the through hole (17b) described above, the header tank (14) is configured by fitting the second header member (17) on the first header member (16) connected with a plurality of the tubes (11), and the through hole (17b) can alternatively be formed in the second header member (17).

In this case, before tacking the second header member (17) and the first header member (16) to each other, the connectors (20, 21) can be tacked on the second header member (17). With the header tank (14) not yet cylindrical, therefore, the connectors (20, 21) can be tacked on the second header member (17). As a result, the workability of tacking the connectors (20, 21) on the second header member (17) is improved.

Further, the improved workability reduces the production cost of the heat exchanger. Also, the through hole (17b) can be easily formed in the second header member (17) in press, etc. and therefore, unlike in the prior art in which a notch is formed on each of the two component parts including the second header member (17) and the first header member (16), the production cost of the heat exchanger is reduced while at the same time improving the geometric dimensional accuracy of the through hole (17b).

Also, in the heat exchanger according to the first aspect having the first header member (16) and the second header member (17) described above, the second header member (17) has a pair of fitting steps (17a) having an L-shaped section fitted with the first header member (16), and the through hole (17b) may be arranged adjacently to any of the fitting steps (17a).

In this case, the fitting steps (17a) having the L-shaped section not only facilitate the positioning of the first header member (16) on the second header member (17) but also improve the rigidity of the second header member (17). By arranging the through hole (17b) adjacent to any one of the fitting steps (17a), therefore, the deformation of the through hole (17b) at the time of tacking by caulking can be suppressed further.

Also, in the heat exchanger according to the first aspect described above, the through hole (17b) is open in the direction (B) perpendicular to the length of the tubes (11), and the connectors (20, 21) may be arranged on the header tank (14) in such a manner as to project outward in the direction (B) perpendicular to the length of the tubes (11) from the opening of the through hole (17b).

In this case, the connectors (20, 21) are not projected to an unnecessary degree outward along the length of the tubes (11) from the header tank (14), with the result that the connectors (20, 21) can be properly coupled to the header tank (14) without increasing the size of the heat exchanger.

Also, in the heat exchanger according to the first aspect described above, the connectors (20, 21) each have positioning portions (20c) set in position by contact with the outer peripheral portion of the header tank (14), and the coupling surface may be the contact portion between the positioning portions (20c) and the header tank (14).

In this case, the connectors (20, 21) can be tacked on the header tank (14) with a higher positioning accuracy and, therefore, the mounting dimensional accuracy is improved after coupling the connectors (20, 21) and the header tank (14).

Further, since the contact portion between the positioning portions (20c) and the header tank (14) makes up a coupling surface, the coupling strength between the connectors (20, 21) and the second header member (17) can be improved by shaping the positioning portions (20c) adapted to the outer periphery of the header tank (14).

According to a second aspect of the invention, there is provided a method of producing a heat exchanger including a cylindrical header tank (14) connected to a plurality of tubes with a fluid passing therein and a pair of connectors (20, 21) for fluid pipe connection, comprising the steps of tacking the connectors (20, 21) on the header tank (14) by deforming a part of the connectors (20, 21), and coupling by brazing the connectors (20, 21) and the header tank (14) to each other after the tacking step.

In this case, the heat exchanger according to the first aspect can be produced. Thus, there is provided a heat exchanger with the connectors (20, 21) properly coupled to the header tank (14).

Also, the tacking step of the heat exchanger production method according to the second aspect described above may include the step of preparing the header tank (14) having a through hole (17b) communicating between inside and outside thereof, the step of preparing the connectors (20, 21) each having a protrusion (20b) insertable into the through hole (17b) and the step of expanding the protrusion (20b) toward the inner periphery of the through hole (17b) after being inserted into the through hole (17b).

In this case, specifically, the protrusion (20b) is inserted in the through hole (17b) and further expanded toward the inner periphery of the through hole (17b). Therefore, the connectors (20, 21) can be easily tacked on the header tank (14). Further, the connectors (20, 21) can be caulked on the outer peripheral surface of the header tank (14) without unnecessarily increasing the size of the header tank (14).

Also, the tacking step of the heat exchanger production method according to the second aspect described above may include the step of imposing a load on the protrusion (20b) in the direction parallel to the length of the header tank (14) after inserting the protrusion (20b) into the through hole (17b). By doing so, the header tank (14) is not easily deformed in longitudinal direction, and therefore the deformation of the through hole (17b) can be suppressed also under the load imposed on the protrusion (20b) in the direction parallel to the length of the header tank (14).

Also, the tacking step of the heat exchanger production method according to the second aspect described above may include the step of preparing the header tank (14) so configured that the second header member (17) having the through hole (17b) is fitted on the first header member (16) connected with a plurality of the tubes (11) and the step of fitting the second header member (17) on the first header member (16) after deforming the protrusion (20b) by being inserted into the through hole (17b).

With this configuration, before fitting the second header member (17) and the first header member (16) one on the other, the connectors (20, 21) are tacked on the second header member (17). Therefore, the connectors (20, 21) can be tacked on the second header member (17) with the header tank (14) not yet cylindrical. As a result, the workability of tacking the connectors (20, 21) on the second header member (17) is improved.

Also, the tacking step of the heat exchanger production method according to the second aspect described above may include the step of preparing the header tank (14) with the through hole (17b) open in the direction (B) perpendicular to the length of the tubes (11) and the step of arranging the connectors (20, 21) on the header tank (14) in such a manner as to project outward in the direction (B) perpendicular to the length of the tubes (11) from the opening of the through hole (17b).

In this case, the connectors (20, 21) are arranged on the header tank (14) in such a manner as to project outward in the direction (B) perpendicular to the length of the tubes (11) from the opening of the through hole (17b), and therefore, a heat exchanger can be produced in which the connectors (20, 21) are not projected to an unnecessary degree outward along the length of the tubes (11) from the header tank (14).

The reference numerals in the parentheses attached to each means described above and in the claims indicate the correspondence with the specific means described in the embodiments below.

The present invention may be more fully understood from the description of preferred embodiments of the invention, as set forth below, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a general configuration of a heat exchanger according to an embodiment of the invention.

FIG. 2 is a sectional view taken in line A-A in FIG. 1.

FIG. 3A is a sectional view, taken in line A-A in FIG. 1, showing the second header member as a unit according to an embodiment, and FIG. 3B is a front view of the second header member shown in FIG. 3A.

FIG. 4A is a sectional view, taken in line A-A in FIG. 1, showing the connector as a unit according to an embodiment, and FIG. 4B is a front view of the connector shown in FIG. 4A.

FIG. 5A is a sectional view, taken in line A-A in FIG. 1, showing the second header member and the connector according to an embodiment, and FIG. 5B is a sectional view thereof taken in line C-C in FIG. 5A.

FIG. 6 is a diagram for explaining the first tacking step according to an embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a front view showing a general configuration of the heat exchanger according to an embodiment of the invention. This heat exchanger functions as a condenser of an automotive air conditioning system in which a high-temperature high-pressure refrigerant discharged from a compressor (not shown) is condensed by radiating heat into the air. The fluid according to this embodiment, therefore, is a refrigerant. In FIG. 1, arrows “up”, “down”, “left” and “right” indicate the directions as viewed from the front of the vehicle with the heat exchanger mounted thereon.

The condenser 1 is so configured that a multiplicity of refrigerant tubes 11 with the refrigerant flowing therein are stacked, and fins 12 for promoting the heat exchange between the refrigerant and the air are arranged between the adjacent refrigerant tubes 11. The refrigerant tubes 11 and the fins 12 make up a substantially rectangular core unit constituting a heat exchange unit.

The refrigerant tubes 11 each have a flat cross section and a single or a multiplicity of holes. The multiplicity of the refrigerant tubes 11 are arranged in parallel at predetermined spatial intervals with the flat surfaces thereof parallel to each other. The air with which the refrigerant exchanges heat flows from the front to rear side of the vehicle, i.e. from the front toward the back of the page in FIG. 1.

A first refrigerant header tank 14 for distributing the refrigerant to the refrigerant tubes 11 and a second refrigerant header tank 15 for collecting the refrigerant from the refrigerant tubes 11 are arranged at the longitudinal ends, respectively, of the refrigerant tubes 11.

The first and second refrigerant header tanks 14, 15 are cylindrical members extending along the direction in which the multiplicity of the refrigerant tubes 11 are arranged. The first and second refrigerant header tanks 14, 15 each have an inner surface connected with the refrigerant tubes 11, a back surface located out on the other side far from the inner surface, a front surface located forward in the direction of air flow and a rear surface located backward in the direction of air flow.

The first refrigerant header tank 14 is a cylindrical header tank of segmentation type formed of a first header member 16 extending vertically and connected with the tubes 11 and a second header member 17 extending vertically in conformity with, and fitted on, the first header member 16.

The second refrigerant header tank 15, like the first refrigerant header tank 14, is a cylindrical header tank of segmentation type formed of a first header member 18 and a second header member 19 fitted one on the other. Generally, the first header members 16, 18 are called the plate headers, and the second header members 17, 19 the tank headers.

The first header members 16, 18 each have as many slits (not shown) as the refrigerant tubes 11, through which the first header members 16, 18 communicate with all the refrigerant tubes 11. Also, the second header member 17 of the first refrigerant header tank 14 is coupled to a first connector 20 connected to a refrigerant inflow pipe (not shown) through which the refrigerant flows into the condenser 1 and a second connector 21 connected to a refrigerant outflow pipe (not shown) through which the refrigerant flows out of the condenser 1.

The second header members 17, 19 are gutter-shaped plate members (having a substantially arcuate cross section). The second header members 17, 19 each have a convex back surface curved outward, and fitting steps 17a having an L-shaped cross section for receiving and fitted with the first header members 16, 18 are spread from the curved surface part along the length of the first and second refrigerant header tanks 14, 15 on both sides of the curved surface part. Thus, the curved surface part and the fitting steps make up the front and rear surfaces, respectively.

The fitting steps 17a, as shown in FIGS. 2, 3 and described later, each include an enlarged portion 17c expanded along the direction of air flow B and a side wall portion 17d expanded to receive the first header members 16, 18 along the length of the refrigerant tubes 11.

The fitting steps 17a both facilitate the positioning of the first header members 16, 18 and improve the rigidity. The upper and lower ends of the first and second refrigerant header tanks 14, 15 are closed by dished tabular members (tank caps 27, 28).

Now, the first refrigerant header tank 14 and the first connector 20 are explained in detail with reference to FIGS. 2 to 4. FIG. 2 is an enlarged sectional view taken in line A-A in FIG. 1. The first header member 16 of the first refrigerant header tank 14, substantially tabular and vertically elongate, has the slits as described above. Further, flat plate portions 16a to be combined with the second header member 17 are arranged along the vertically extending ends thereof.

The direction of arrow B in FIG. 2 is perpendicular to the length of the tubes 11. The arrow B also represents the direction in which the air to exchange heat with the refrigerant flows. Next, the second header member 17 is explained in detail with reference to FIGS. 3A, 3B. FIG. 3A is a sectional view of the same portion of a unit of the second header member 17 as the section taken in line A-A in FIG. 1, and FIG. 3B is a front view of FIG. 3A.

The second header member 17, having a substantially semicircular cross section, is vertically elongated. Further, the second header member 17 includes vertically-extending fitting steps 17a each having an L-shaped section adapted to receive and fit on the first header member 16 and a rectangular through hole 17b for establishing communication between inner and outer surface of peripheries of the second header member 17.

The fitting steps 17a are combined with the flat plate portions 16a of the first header member 16. By combining the fitting steps 17a and the flat plate portions 16a with each other, the first refrigerant header tank 14 is formed cylindrically thereby to make up a refrigerant space 14b for collecting/distributing the refrigerant therein as shown in FIG. 2.

The through hole 17b is opened in such a manner as to establish communication between the inner and outer surface of peripheries of the second header member. Once the first header member 16 is combined with the second header member 17 to make up the cylindrical refrigerant header tank 14, therefore, the through hole 17b is formed on the side of the cylinder of the first refrigerant header tank 14.

Further, the through hole 17 is open in the direction (along arrow B) perpendicular to the length of the tubes 11. This through hole 17b is connected with the first connector 20. The expression “open in the direction (along arrow B) perpendicular to the length of the tubes 11” means that the opening 17b is visible as viewed from at least the direction (along arrow B) perpendicular to the length of the tubes 11.

Therefore, the meaning “open in the direction (along arrow B) perpendicular to the length of the tubes 11” includes a case in which even if the opening is visible when the second header member 17 is viewed from the direction along the length of the tubes 11 as indicated by arrow B′, the opening is visible from the direction (along arrow B) perpendicular to the length of the tubes 11.

Also, the through hole 17b is open in the front-rear direction from one of the front and rear surfaces of the first refrigerant header tank 14. Thus, the through hole 17b is open in the direction perpendicular to both the length of the tubes 11 and the length of the first refrigerant header tank 14.

Further, the through hole 17b is arranged in the vicinity of one of the fitting steps 17a, or according to this embodiment, adjacently to the fitting step 17a. The through hole 17b has a longitudinal axis along the length of the second header member 17 (first refrigerant header tank 14). Specifically, the opening of the through hole 17b may be rectangular or elliptical and elongate along the length of the second header member 17 (first refrigerant header tank 14).

Next, the first connector 20 is explained in detail with reference to FIGS. 4A, 4B. FIG. 4A is a sectional view of the first connector 20 as a unit taken at the same point as line A-A in FIG. 1, and FIG. 4B a front view taken from the rear side of the vehicle in FIG. 4A. The first connector 20, as shown in FIG. 2, is projected outward in the direction (along arrow B) perpendicular to the length of the tubes 11 from the opening of the through hole 17b of the second header member 17.

Further, the first connector 20 includes a pipe connecting portion 20a connected to the refrigerant inflow pipe, a protrusion 20b inserted into the through hole 17b of the second header member 17 and two positioning portions 20c set in position by contact with the outer periphery of the second header member 17 around the through hole 17b.

The pipe connecting portion 20a has a connecting hole 20d adapted to the outer diameter of the refrigerant inflow pipe and a threaded hole 20e to fix a flange (not shown) mounted on the refrigerant inflow pipe. Also, the protrusion 20b has a communication hole 20f for establishing communication between the connecting hole 20d and the interior of the first refrigerant header tank 14.

Further, the outer periphery of the protrusion 20b is in a shape adapted to the through hole 17b of the second header member 17, and before forming the engaging portions 20g described later, the protrusion 20b is insertable into the through hole 17b. Also, the engaging portion 20g is arranged at each end of the protrusion 20b in longitudinal direction of the second header member 17 (first refrigerant header tank 14) at the forward end of the protrusion 20b.

These engaging portions 20g, after the protrusion 20b is inserted into the through hole 17b, are deformed in the longitudinal direction of the second header member 17 (first refrigerant header tank 14) on the inner periphery of the through hole 17b. In FIGS. 4A, 4B showing the first connector 20 as a unit, reference numeral 20g designates the points at which the engaging portions 20g are formed.

As a result, the deformation by expansion of the fitting steps 17a is suppressed. Further, the engaging portions 20g provide a mechanical engaging means to tack the first connector 20 on the second header member 17 (first refrigerant header tank 14).

Also, the engaging portions 20g are located inside the first refrigerant header tank 14. The second header member 17 is held between the engaging portions 20g and the pipe connecting portion 20a of the connector 20 located outside the first refrigerant header tank 14 and sufficiently larger than the through hole 17b thereby to tack the first connector 20. Further, the outer periphery of the protrusion 20b is caulked and strongly tacked on the inner periphery of the through hole 17b by deforming the engaging portions 20g.

A coupling surface is formed by the outer surface of the second header member 17 around the through hole 17b. Another coupling surface is formed by the outer surface of the positioning portion 20c of the connector 20 around the base of the protrusion 20b. These coupling surfaces are coupled by brazing with a brazing material interposed therebetween.

As shown in FIG. 2, the protrusion 20b is inserted into the through hole 17b, and therefore, the refrigerant flowing out of the refrigerant inflow pipe flows into the first refrigerant header tank 14 through the connecting hole 20d and the communication hole 20f. The connecting hole 20d and the communication hole 20f thus make up a fluid path of the first connector 20 according to this embodiment.

One of the two positioning portions 20c is in a shape adapted to the curved outer peripheral surface of the second header member 17, and the other positioning portion 20c in a shape adapted to the outside of each fitting step 17a of the second header member 17. The second header member 17 of the first refrigerant header tank 14 has a through hole (not shown) similar to the through hole 17b for coupling the second connector 21. This through hole of the fist refrigerant header tank 14 is coupled to the second connector 21 having a similar configuration to the first connector 20.

A gas-liquid separator 22 is arranged, as shown in FIG. 1, on the left side (far from the core unit 13) of the second refrigerant header tank 15. This gas-liquid separator 22 is a receiver capable of storing the liquid-phase refrigerant by separating the gas-phase refrigerant and the liquid-phase refrigerant from each other.

The second refrigerant header tank 15 and the gas-liquid separator 22 are coupled to each other through a mounting member 22a. Further, the second refrigerant header tank 15 and the gas-liquid separator 22 communicate with each other at two points through a plate 23 having two through holes 23a, 23b. The through hole 23a is arranged above the through hole 23b.

A first separator 14a is arranged at the lower part in the first refrigerant header tank 14, and a second separator 15a is arranged at the same height as the first separator 14a in the second refrigerant header tank 15. The core unit 13 is divided into two heat exchange units by the first and second separators 14a, 15a.

First, the upper part of the first and second separators 14a, 15a of the core unit 13 makes up a condensing portion 13a for condensing the refrigerant by heat exchange between the air and the gas-phase refrigerant influent from the first connector 20. The refrigerant flowing out of the condensing portion 13a flows into the gas-liquid separator 22 by way of a through hole 23a of a plate 23. Thus, the first connector 20 is arranged above the first separator 14a, and the through hole 23a above the second separator 15a.

Further, the lower part of the first and second separators 14a, 15a of the core unit 13 makes up a supercooling portion 13b for cooling the liquid-phase refrigerant by heat exchange between the air and the liquid-phase refrigerant flowing in by way of a through hole 23b from the gas-liquid separator 22. The refrigerant cooled by the supercooling portion 13b flows out from a refrigerant outlet port 17. Thus, the second connector 21 is arranged below the first separator 14a, and the through hole 23b below the second separator 15a.

In the condenser according to this embodiment, therefore, the supercooling portion 13b is arranged below the condensing portion 13a, the gas-liquid separator 22 is arranged on the side of the condensing portion 13a and the supercooling portion 13b, and the upper part of the gas-liquid separator 22 is projected above the upper end surface of the condensing portion 13a. A first bracket 24 for coupling the condenser 1 to other parts (such as the vehicle body or other heat exchangers) is arranged on the part of the gas-liquid separator 22 projected above the upper end surface of the condensing portion 13a.

Also, a pair of side plates 25 extending in parallel to the refrigerant tubes 11 for reinforcing the core unit 13 are arranged on the side ends of the core unit 13 in the direction in which the refrigerant tubes 11 are stacked. A pair of brackets 26 for mounting the condenser 1 on other component parts are arranged at two points on the side plate 25 at the lower side end of the core unit 13 in the direction in which the refrigerant tubes 11 are stacked.

Tank caps 27, 28 are arranged at the upper and lower ends, respectively, of the first refrigerant header tank 14 and the second refrigerant header tank 15. The tank caps 27 are arranged at the lower end of the first refrigerant header tank 14 and at the upper and lower ends of the second refrigerant header tank 15 thereby to close the respective ends of the refrigerant header tanks.

Further, the tank cap 28, arranged at the upper end of the first refrigerant header tank 14, closes the upper end of the first refrigerant header tank 14, and includes a second bracket 29 for coupling the condenser 1 to other component parts.

The condenser 1 is configured as described above. Further, according to this embodiment, all the component parts of the condenser 1 are made of an aluminum alloy and integrally coupled by brazing. The term “brazing”, as described in “Connection and Coupling Techniques”, Publication Office, Tokyo Electrical Engineering College, for example, is the technique for coupling a base metal, without melting it, using a brazing or soldering material.

More specifically, the coupling technique using a filler material (brazing material) having the melting point of not lower than 450° C. is called brazing, while the coupling technique using a filler material (solder) having the melting point of lower than 450° C. is called soldering. According to this embodiment, as described later, the component parts of the condenser 1 are coupled to each other integrally by brazing.

Next, the process of producing the condenser 1 is explained. First, according to this embodiment, the first and second connectors 20, 21 are tacked on the second header member 17, and further, the second header member 17 and the first header member 16 are fitted and tacked on each other. According to this embodiment, this process constitutes the tacking.

In the tacking process, as described below, the step of tacking the first and second connectors 20, 21 on the second header member 17 is called the first tacking step, and the step of fitting and tacking the second header member 17 and the first header member 16 on each other is called the second tacking step.

The first tacking step is explained in detail with reference to FIGS. 5A, 5B, 6. The step of tacking the first connector 20 on the second header member 17 and the step of tacking the second connector 21 are similar to each other. Therefore, only the step of tacking the first connector 20 is explained with reference to FIGS. 5A, 5B and 6.

First, in the first tacking step, as shown in FIGS. 5A, 5B, the protrusion 20b of the first connector 20 is inserted into the through hole 17b of the second header member 17. FIG. 5A is a sectional view at the same part as the sectional view taken in line A-A in FIG. 1 with the protrusion 20b of the first connector 20 inserted into the through hole 17b of the second header member 17. FIG. 5B is a sectional view taken in line C-C in FIG. 5A. FIG. 6 is a diagram for explaining the tacking operation of the first tacking step.

Under this condition, the protrusion 20b is inserted into the through hole 17b in such a manner that the positioning portion 20c formed on the first connector 20 is in contact with the periphery of the through hole 17b of the second header member 17. As a result, the first connector 20 is set in position on the second header member 17.

Further, by this positioning process, the first connector 20 is arranged on the first refrigerant header tank 14 in such a manner as to project outward in the direction (along arrow B) perpendicular to the length of the tubes 11 from the opening of the through hole 17b.

Next, with the protrusion 20b inserted into the through hole 17b, as shown in FIG. 6, the second header member 17 and the first connector 20 are fixed using backup jigs 30. Under this condition, an engaging portion-forming jig 31 is applied in the direction of arrow D thereby to deform the protrusion 20b of the first connector 20.

Specifically, the forward end of the engaging portion-forming jig 31 is in such a shape as to be insertable into the communication hole 20f of the first connector 20 and has a progressively larger sectional area along the direction of arrow F in FIG. 5B. By applying the engaging portion-forming jig 31 in the direction of arrow D in FIG. 6, therefore, the inner periphery of the communication hole 20f is forcibly widened toward the through hole 17b thereby to widen the outer periphery of the protrusion 20b.

As a result, the forward end of the protrusion 20b of the first connector 20 is deformed in the longitudinal direction of the second header member 17 on the inner periphery of the through hole 17b thereby to form engaging portions 20g. At the same time, the outer periphery of the protrusion 20b of the first connector 20 is tacked by being caulked on the inner periphery of the through hole 17b.

Especially, with the engaging portion-forming jig 31 according to this embodiment, the outer periphery of the protrusion 20b is forcibly widened along the length of the second header member 17 (the direction of arrow F in FIG. 5B). This is by reason of the fact that in the case where the protrusion 20b is deformed under the load in the directions of arrows E in FIG. 5A, for example, the through hole 17b is easily extended and easily deformed in the circumferential direction along the curved outer periphery of the second header member 17.

By deforming the protrusion 20b under the load along the direction of arrow F parallel to the length of the second header member 17, on the other hand, the deformation of the through hole 17b can be suppressed. As a result, the first connector 20 can be positively tacked on the second header member 17. Further, according to this embodiment, the second connector 21 is similarly tacked on the second header member 17.

After the first tacking step described above, the second header member 17 and the first header member 16 are fitted and tacked one on the other in the second tacking step. As described above, the flat plate portions 16a of the first header member 16 are fitted and tacked on the fitting steps 17a, respectively, of the second header member 17 thereby to form the cylindrical first refrigerant header tank 14.

Specifically, a hook (not shown) is formed at a predetermined position on each fitting step 17a of the second header member 17 and bent along the outer periphery of the first header member 16, so that the second header member 17 and the first header member 16 are tacked by caulking one on the other. According to this embodiment, at the same time as the second tacking step, the cylindrical second refrigerant header tank 15 is formed by combining and tacking by caulking the second header member 19 and the first header member 18 one on the other as in the first refrigerant header tank 14.

After the second tacking step described above, a multiplicity of the refrigerant tubes 11 are inserted into the slits formed in the first refrigerant header tank 14 and the second refrigerant header tank 15. At the same time, the fins 12 are interposed between the refrigerant tubes 11 thereby to assemble the condenser 1.

One side plate 25 is arranged above the uppermost refrigerant tube 11 through the fins 12, and the other side plate 25 is arranged through the fins 12 under the lowest refrigerant tube 11. This assembly then is tacked by being bound vertically with a wire.

Further, the first separator 14a is tacked at a predetermined position in the first refrigerant header tank 14. The plate 23 is tacked by being caulked at the position of the communication hole formed in advance in the second refrigerant header tank 15, and the gas-liquid separator 22 with the first bracket 24 tacked by being caulked thereon is tacked by being caulked through a mounting member 22a. Also, the second separator 15a is tacked by being caulked at a predetermined position in the second refrigerant header tank 15.

Further, the bracket 26 for mounting other parts is tacked by being caulked on the lower side plate 25. Under this condition, the whole assembly is fixed in position by exclusive jigs from both sides. The tank caps 27 are tacked by caulking at the upper and lower ends of the second refrigerant header tank 15 and the lower end of the first refrigerant header tank 14. Also, the tank cap 28 having the second bracket 29 is tacked by caulking at the upper end of the first refrigerant header tank 14.

The whole condenser 1 thus tacked is heated to about 600° C. by a heating means thereby to melt the brazing material clad in advance on the surface of each component part. Then, the condenser 1 is cooled again until the brazing material is solidified. In this way, the component parts are integrally brazed and the condenser 1 is produced. According to this embodiment, therefore, this brazing step makes up the coupling step for coupling the first and second connectors 20, 21, the second header member 17 and the first header member 16.

In the condenser 1 according to this embodiment, as described above, the forward end of the first connector 20 is deformed in the longitudinal direction of the second header member 17 on the inner periphery of the through hole 17b thereby to make up the engaging portions 20g. Therefore, the first connector 20 can be positively tacked on the first refrigerant header tank 14. In addition, the outer periphery of the protrusion 20b of the first connector 20 is strongly tacked by caulking on the inner periphery of the through hole 17b.

Further, in view of the fact that the first connector 20 is tacked on the second header member 17 before the second header member 17 and the first header member 16 are combined with each other, the first refrigerant header tank 14 is not yet cylindrical in shape at the time of tacking the first connector 20 on the second header member 17. As a result, the workability of tacking the first connector 20 on the second header member 17 is improved.

The improved workability reduces the production cost of the condenser 1. Further, since the through hole 17b can be easily formed in the second header member 17 by press work or the like, the production cost of the condenser 1 can be reduced as compared with the conventional technique in which a notch is formed on each of the two component parts, i.e. the second header member 17 and the first header member 16.

Also, the first connector 20, which is arranged to project in the direction (along arrow B) perpendicular to the length of the tubes 11 from the opening of the through hole 17b of the second header member 17, is not projected outward along the length of the tubes 11 from the first refrigerant header tank 14. As a result, the condenser 1 can be reduced in size.

In this specification, the wording “the first connector 20 is not projected outward along the length of the tubes 11 from the first refrigerant header tank 14” means that as in this embodiment, for example, the axes of the connection hole 20d and the communication hole 20f formed in the first connector 20 follow the direction (the direction of arrow B) perpendicular to the length of the tubes 11, and therefore the first connector 20 is not unnecessarily displaced outward along the length of the tubes from the first refrigerant header tank 14.

The wording “the first connector 20 is not projected outward along the length of the tubes 11 from the first refrigerant header tank 14”, therefore, is applicable substantially to a configuration in which the pipe connecting portion 20a or the like is displaced outward along the length of the tubes 11 from the first refrigerant header tank 14 due to the shape of the flange of the refrigerant inflow pipe and the refrigerant outflow pipe.

Also, in the condenser 1 according to this invention, the through hole 17b is formed directly in the second header member 17. As compared with the prior art in which the through hole is formed by combining the second header member and the first header member, therefore, the dimensional accuracy of the through hole 17b is improved. Further, the absence of a step around the through hole 17b reduces the geometric variations of the periphery of the through hole 17b.

Furthermore, in view of the fact that the through hole 17b is arranged adjacently to the fitting step 17a of the second header member 17, the deformation of the through hole 17b in the first tacking step is suppressed. Thus, the protrusion 20b can be tacked positively in the through hole 17b. Further, the positioning portions 20c assure a more positive positioning, thereby improving the mounting dimensional accuracy after coupling the first connector 20 and the first refrigerant header tank 14 to each other.

In addition, as the positioning portions 20c are in such a shape as to adapt to the outer periphery of the second header member 17 around the through hole 17b, the contact portion between the positioning portions 20c and the second header member 17 constitutes a coupling surface for an improved coupling strength between the first connector 20 and the second header member 17.

Also, as compared with the prior art, the geometric variations around the through hole 17b can be reduced, and therefore, the shape adjustment of the first connector 20, which otherwise might be required by an independent cutting process to assure adaptation of the shape of the protrusion 20b and the positioning portions 20c of the first connector 20 to the outer periphery of the first refrigerant header tank 14, is not required.

Thus, the first connector 20 can be easily produced by cold forging or the like. As a result, the production cost of the first connector 20 can be reduced, thereby reducing the production cost of the condenser 1 as a whole. Exactly the same effects are obtained for the second connector 21 as for the first connector 20.

Other Embodiments

This invention is not limited to the embodiments described above but can be variously modified as described below.

• (1) Unlike in the embodiments described above employing the condenser 1 of a subcool type for supercooling the liquid-phase refrigerant, a condenser having neither the supercooling unit 13b nor the gas-liquid separator 22 may be used.
• (2) The first and second connectors 20, 21, though coupled to the second header member 17 of the first refrigerant header tank 14 in the embodiments described above, may alternatively be coupled to the second header member 19 of the second refrigerant header tank 15. The connectors 20, 21 may of course be coupled to the second header members 17, 19 of the first and second refrigerant header tanks 14, 15, respectively.
• (3) Unlike in the embodiments described above in which the protrusion 20b is formed on the first connector 20 as a tacking portion, the tacking portion is not limited to this configuration. As an alternative, a tabular hook is formed on the first connector 20 and bent along the outer periphery of the second header member 17. In this way, the first connector 20 may be engaged with and tacked on the header tank 14.
• (4) In the embodiments above, the component parts such as the first connector 20 and the second connector 21 are coupled by brazing to the condenser. The component parts of the invention, however, are not limited to the ones used in the embodiments described. Instead, the component parts that can be brazed and, as required by the type and application of the heat exchanger, may be integrally brazed after being tacked by caulking or the like.
• (5) Examples of application of the invention to the condenser of the automotive vehicles are described in the aforementioned embodiments. Nevertheless, the condenser according to the invention is applicable to the heat exchangers in general as well as a vehicle condenser without departing from the spirit of the invention.

While the invention has been described by reference to specific embodiments chosen for purposes of illustration, it should be apparent that numerous modifications could be made thereto, by those skilled in the art, without departing from the basic concept and scope of the invention.

Claims

1. A heat exchanger comprising a cylindrical header tank connected with a plurality of tubes through which a fluid passes and a pair of connectors each for connecting a fluid pipe,

wherein the connectors each have a tacked portion engaging the header tank, and

wherein the connectors and the header tank have a coupling surface therebetween, respectively, coupled by brazing to each other.

2. A heat exchanger according to claim 1,

wherein the header tank has a through hole for establishing communication between the inside and the outside of the header tank,

wherein the connectors each have a protrusion adapted to be inserted into the through hole, and

wherein the tacked portion makes up engaging portions configured by deforming the protrusion.

3. A heat exchanger according to claim 2,

wherein the protrusion is caulked on the inner periphery of the through hole.

4. A heat exchanger according to claim 2,

wherein the through hole is formed on the side of the cylinder of the header tank.

5. A heat exchanger according to claim 2,

wherein an opening of the through hole is in the shape elongated along the length of the header tank.

6. A heat exchanger according to claim 2,

wherein the engaging portion is arranged on each end of the protrusion in a longitudinal direction of the header tank.

7. A heat exchanger according to claim 2,

wherein the header tank is configured by fitting the second header member on the first header member connected with a plurality of the tubes, and

wherein the through hole is formed in the second header member.

8. A heat exchanger according to claim 7,

wherein the second header member has a pair of fitting steps each having an L-shaped section fitted with the first header member, and

wherein the through hole is arranged adjacently to the fitting steps.

9. A heat exchanger according to claim 2,

wherein the through hole is open in the direction perpendicular to the length of the tubes, and

wherein the connectors are arranged on the header tank in such a manner as to project outward in the direction perpendicular to the length of the tubes from the opening of the through hole.

10. A heat exchanger according to claim 1,

wherein the connectors each have a positioning portion set in position by contact with the outer periphery of the header tank, and

wherein the coupling surface is the contact portion between the positioning portion and the header tank.

11. A method of producing a heat exchanger including a cylindrical header tank connected with a plurality of tubes with a fluid passing therein and connectors for fluid pipe connection, comprising the steps of:

tacking the connectors on the header tank by deforming a part of the connectors, and

coupling by brazing the connectors and the header tank one on the other after the tacking step.

12. A method of producing a heat exchanger according to claim 11,

wherein the tacking step includes the step of preparing the header tank having a through hole communicating between inside and outside thereof and the connector having a protrusion insertable into a through hole, and

wherein the protrusion is expanded toward the inner periphery of the through hole after being inserted into the through hole.

13. A method of producing a heat exchanger according to claim 12,

wherein the tacking step includes the step of imposing a load parallel to the length of the header tank on the protrusion after inserting the protrusion into the through hole.

14. A method of producing a heat exchanger according to claim 12,

wherein the tacking step includes the step of preparing the header tank in which the second header member having the through hole is fitted on the first header member connected with a plurality of the tubes, and

wherein after inserting the protrusion into the through hole and deforming the protrusion, the second header member is fitted on the first header member.

15. A method of producing a heat exchanger according to claim 11,

wherein the tacking step includes the step of preparing the header tank having the through hole open in the direction perpendicular to the length of the tube, and

wherein the connectors are arranged on the header tank in such a manner as to project outward in the direction perpendicular to the length of the tubes from the opening of the through hole.