Scroll Compressor

Abstract

The invention provides a scroll compressor in which a movable scroll is supported from a back face with a plurality of thrust plates without being inclined. The scroll compressor of the invention has a compression unit including a movable scroll made up by forming a vortical wrap in an end wall and a similar fixed scroll, and being capable of carrying out compression along with an orbiting movement of the movable scroll with the wraps of the scrolls engaged with each other; a movable-scroll receiving support surface formed on a back-face side of the end wall of the movable scroll and including a flat face opposite to the back face of the end wall; and a plurality of thrust plates that are scattered in the support surface along a circumferential direction of the movable scroll, slidably supports the back face of the end wall of the movable scroll, and receives a thrust load from the movable scroll. The thrust plates are fixed onto the flat face of the support surface so as to be supported with the flat face by using the flat face as reference.

Description

TECHNICAL FIELD

The present invention relates to a scroll compressor in which a fixed scroll and a movable scroll are combined together to carry out compression.

BACKGROUND ART

Scroll compressors are used in automobile air-conditioning systems, home air-conditioners, refrigerators, etc. Many of these scroll compressors use a compression unit in which a vortical wrap of a fixed scroll and that of a movable scroll are engaged with each other.

In the compression unit, the orbiting movement of the movable scroll gradually reduces the capacity of a crescent-shaped compression chamber that is formed between the vortical wrap of the fixed scroll and that of the movable scroll. This action of the compression chamber is used to compress a to-be-compressed fluid such as a refrigerant.

During compression, the movable scroll is applied with load in an axial direction, namely in a thrust direction, as a reaction force of the compression. In other words, the load acts to separate the movable scroll away from the fixed scroll. In order to suppress this action that deteriorates the compression performance, the scroll compressor is provided with a movable-scroll receiving support surface in the back face of an end wall supporting the wrap of the movable scroll, and also provided with a thrust receiving structure for receiving a thrust load in the movable-scroll receiving support surface.

The thrust receiving structure is required to be designed in consideration of downsizing of the compressor.

In late years, as shown in Unexamined Patent Publication No. 2005-291151, it has been suggested to provide a thrust receiving structure with a plurality of thrust plates made up of small disc-like parts in the movable-scroll receiving support surface to be arranged in a circumferential direction of the movable scroll by using an embedding construction. Recessed areas are formed in a flat section of the movable-scroll receiving support surface, which faces the end wall of the movable scroll, along the circumferential direction of the movable scroll. The thrust plates are interfitted in their respective recessed areas so that the upper faces of the thrust plates slightly project from the openings of the recessed areas. In other words, the thrust plates supported with the bottom faces of the recessed areas each have a structure for receiving the end wall of the movable scroll. As this structure uses a plurality of disc-like thin parts, it has the advantage that the thrust receiving structure itself is compact.

Preferably, in order to maintain the compression performance, the movable scroll orbits around the axis of the fixed scroll while keeping a parallel attitude.

In the structure disclosed in Unexamined Patent Publication No. 2005-291151, however, the thrust plates are supported with the bottom faces of the recessed areas, so that the movable scroll is inevitably affected by variation generated during the machining of the recessed areas.

More specifically, the recessed areas are formed in the respective sections of the movable-scroll receiving support surface by machining. However, the machining is prone to generate variation in a depth direction. The thrust plates are the parts arranged along the circumferential direction of the movable scroll and supporting the movable scroll from the back face of the movable scroll. The depth-directional variation in the recessed areas emerges as an inclination of the movable scroll. This means that the movable scroll is engaged with the fixed scroll in an inclined position due to the thrust plates.

This inclination of the movable scroll affects a compression stroke that is carried out between the fixed and movable scrolls and is liable to cause a deterioration in compression performance.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a scroll compressor in which a movable scroll is supported from a back face with a plurality of thrust plates without being inclined.

The scroll compressor according to the invention has a compression unit including a movable scroll made up by forming a vortical wrap in an end wall and a similar fixed scroll, and being capable of carrying out compression along with an orbiting movement of the movable scroll with the wraps of the scrolls engaged with each other; a movable-scroll receiving support surface formed on a back-face side of the end wall of the movable scroll and including a flat face opposite to the back face of the end wall; and a plurality of thrust plates that are scattered in the support surface along a circumferential direction of the movable scroll, slidably supports the back face of the end wall of the movable scroll, and receives a thrust load from the movable scroll. The thrust plates are fixed onto the flat face of the support surface so as to be supported with the flat face by using the flat face as reference.

Since the invention has a structure in which the thrust plates are supported with the flat face of the scroll-receiving support surface that can be maintained with high accuracy, the movable scroll can be supported with the thrust plates from the back face without being unnecessarily inclined.

It is therefore possible to suppress a reduction in compression performance, which is caused by inclination of the movable scroll, and then to improve the compression performance of the scroll compressor.

Preferably, according to the scroll compressor of the invention, each of the thrust plates has a projection protruding toward the support surface, and the support surface has a hole that opens toward the corresponding thrust plate. Each of the thrust plates is fixed onto the support surface by interfitting the corresponding projection into the corresponding hole.

With this scroll compressor, the thrust plates are firmly fixed onto the flat face of a scroll-receiving support surface without inclining the thrust plates with a simple structure.

Preferably, according to the scroll compressor of the invention, the support surface has a projection protruding toward the corresponding thrust plate, and each of the thrust plates has a hole that opens toward the support surface. Each of the thrust plates is fixed onto the support surface by interfitting the corresponding projection into the corresponding hole.

With this scroll compressor, the thrust plates are firmly fixed onto the flat face of the scroll-receiving support surface without inclining the thrust plates with a simple structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a normal sectional view of a scroll compressor according to a first embodiment of the invention;

FIG. 2 is a sectional view taken along line II-II of FIG. 1;

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is an exploded perspective view showing a fixing structure of a thrust plate;

FIG. 5 is a sectional view showing a substantial part of a second embodiment of the invention; and

FIG. 6 is an exploded perspective view showing a fixing structure of a thrust plate according to the second embodiment.

BEST MODE OF CARRYING OUT THE INVENTION

The invention will be described with reference to a first embodiment shown in FIGS. 1 to 4.

FIG. 1 is a normal sectional view of a scroll compressor, or for example, an electric scroll compressor for vehicle air-conditioning. FIG. 2 is a sectional side view taken along line II-II of FIG. 1. FIG. 3 is a partially sectional view taken along line of FIG. 2. FIG. 4 shows a fixing structure of a thrust plate.

In FIG. 1, reference mark 1 represents a housing of the scroll compressor. The housing 1 is constructed by serially connecting a compression-unit casing 1a having a shape of a cylinder with a bottom to a similar electric-unit casing 1b with a cylindrical middle casing 1c disposed therebetween.

A compression unit 5 is installed in the compression-unit casing 1a. The compression unit 5 has a structure in which a fixed scroll 3 disposed on the bottom side of the casing 1a is engaged with a movable scroll 4 disposed on the opening side. More specifically, the fixed scroll 3 and the movable scroll 4 each have a structure in which a vortical wrap 8 is disposed, for example, in a circular end wall 7. In the center of the back face of the end wall 7 of the movable scroll 4, there is a cylindrical boss 11 in which an eccentric bush 10 is rotatably fitted. A wrap 8 of the fixed scroll 3 and a wrap 8 of the movable scroll 4 are engaged with each other. A crescent-shaped compression chamber 12 having capacity varied along with an orbiting movement of the movable scroll 4 is formed between the wraps 8.

In the middle casing 1c, there is formed a cylindrical protruding portion that protrudes close to the end wall 7 of the movable scroll 4. The protruding portion serves as a movable-scroll receiving support surface 13 (hereinafter, referred to as a support surface 13) that receives the movable scroll 4. The support surface 13 has a tip end face that is formed of a ring-like flat face 13a parallel with the end walls 7 of the fixed and movable scrolls 3 and 4. Needless to say, the flat face 13a is situated closely opposite to a back face 7a of the end wall 7.

An electric unit 17 formed by interlocking a rotor 15 and a stator 16 together is installed in the electric-unit casing 1b to be located on the opening side. On the bottom side, there is disposed an inverter unit 18 for controlling the electric unit. The rotor 15 has a shaft 15a including both ends rotatably supported with bearings 19 and 20 that are set in the electric-unit casing 1b and the middle casing 1c. In the shaft 15, an eccentric pin 21 is set in an eccentric position of a shaft end of a shaft 10a supported with the middle casing 1c.

The eccentric pin 21 is inserted in an eccentric aperture located in an eccentric position of the eccentric bush 10 of the movable scroll 4. In result, when the rotation of the rotor 15 is transmitted through the eccentric bush 10 to the movable scroll 4, the movable scroll 4 orbits around an axis of the fixed scroll 3 to vary the capacity of the crescent-shaped compression chamber 12, to thereby compress a to-be-compressed fluid such as refrigerant. The movable scroll 4 does not rotate on its axis and is capable of making an orbiting movement only, by using four pin-type rotation-suppressing devices 22 situated between the end wall 7 of the movable scroll and the support surface 13 as illustrated in FIGS. 1 and 2.

As illustrated in FIGS. 1 and 2, a plurality of thrust plates 25 are scattered along a circumferential direction of the movable scroll 4 between the back face 7a of the end wall 7 of the movable scroll 4 and the ring-like flat face 13a. Each of the thrust plates 25 is made up of a thin circular member (having, for example, a diameter of about 10 mm and a thickness of about 2 mm).

The fixing of the thrust plate 25 uses a structure that supports the entire thrust plate 25 by using the flat face 13a of the support surface 13 as reference plane, in which accuracy can be easily obtained. In this structure, a projection such as a short-columnar projection 28 is formed in either a lower face 25a (one side face opposite to the flat face 13a) of the thrust plate 25 or the flat face 13a (face opposite to the lower face 25a) of the support surface 13 as shown in FIGS. 3 and 4. In the other face, there is formed a hole such as a hole in which the entire protruding projection 28 is fitted, or more specifically, an interfitting hole 29.

The above-mentioned structure will be described in detail. For example, as illustrated in FIGS. 3 and 4, the short-columnar projection 28 is integrally formed in the center (substantially center) of the lower face 25a of the thrust plate 25. A cylindrical interfitting hole 29 with a bottom is formed in each point on the flat face 13a, which coincides with the corresponding projection 28. The interfitting hole 29 has an internal diameter size corresponding to an external diameter of the projection 28 and a depth that is longer than a projection length of the projection 28. Letter H in FIG. 3 indicates the depth of the interfitting hole 29. The projection 28 is slidably (rotatably) interfitted in the interfitting hole 29. The entire projection 28 protruding from the lower face 25a is received in the interfitting hole 29. The thrust plate 25 is thus positioned at a predetermined point, and the lower face 25a of the thrust plate 25 abuts against the flat face 13a. The thrust plate 25 is thus disposed (placed) to be superimposed upon the flat face 13a. The entire thrust plate 25 is supported with the flat face 13a of the support surface 13 from the lower side, and is positioned at a predetermined position. In short, the thrust plate 25 is fitted onto the flat face 13a by using the flat face 13a as reference.

The thrust plate 25 supported with the flat face 13a supports the end wall 7 of the movable scroll 4 from the back-face side, and receives a thrust load applied to the movable scroll 4.

In the scroll compressor, the rotor 15 rotates when the electric unit 17 is excited. The rotation is transmitted from the shaft 15a through the eccentric pin 21 to the movable scroll 4. The movable scroll 4 then orbits around the axis of the fixed scroll 3, and compresses the to-be-compressed fluid such as refrigerant by varying the capacity of the compression chamber 12 located between the wraps 8.

During the compression, the thrust load applied to the movable scroll 4 is received by the plurality of thrust plates 25 supporting the end wall 7.

At this time point, the thrust plate 25 is superimposed upon the flat face 13a. In other words, the thrust plate 25 is positioned by using the flat face 13a as reference.

For that reason, even if there generates variation in the depth direction of the interfitting hole 29 due to the machining of recessed areas, the thrust plate 25 is not affected by the variation. This means that the thrust plate 25 is not inclined. This is because the flat face 13a upon which the thrust plate 25 is superimposed is a section in which high accuracy is easily obtained.

The movable scroll 4 is properly supported from the thrust plates 25 located in any points by using the flat face 13a as reference. The movable scroll 4 is therefore not inclined in relation to the fixed scroll 3, and always retains a predetermined attitude, or a proper fixed attitude suitable for compression. Consequently, the movable scroll 4 can satisfactorily carry out a desired compression performance in cooperation with the fixed scroll 3.

Moreover, the fixing of the thrust plates 25 is carried out without difficulty since the interfitting structure in which the projection 28 and the interfitting hole 29 are fitted together is employed.

FIGS. 5 and 6 show a second embodiment of the invention.

According to the present embodiment, unlike the first embodiment, a pin member 35 is formed as a projection in the flat face 13a of the support surface 13. In the center (substantially center) of the lower face of the thrust plate 25, there is formed a through-hole 36 piercing in thickness direction as a hole, whereby the thrust plate 25 is superimposed upon the flat face 13a.

To be more concrete, the pin member 35 projects towards the lower face of the thrust plate 25. The through-hole 36 has an internal diameter size corresponding to an external diameter of the pin member 35. As illustrated in FIGS. 5 and 6, the pin member 35 is slidably (rotatably) interfitted in the through-hole 36, and the entire pin member 36 protruding from the flat face 13aa is received in the through-hole 36. In result, the thrust plate 25 is positioned at a predetermined point as in the first embodiment, and the entire thrust plate 25 is supported from the lower side by using the flat face 13a of the support surface 13 as reference similarly to the first embodiment.

For that reason, even with the structure opposite to that of the first embodiment in which the pin member 35 and the through-hole 36 are fitted together, it is possible to prevent the inclination of the movable scroll 4 with a simple structure as in the first embodiment.

Members identical to those in the first embodiment are provided with identical reference marks in FIGS. 5 and 6, and descriptions thereof will be omitted.

The invention is not limited to the first and second embodiments, and may be modified in various ways without deviating from the gist of the invention. For example, the embodiments have a structure in which the projection and the through-hole are formed in the lower face of the thrust plate, and the hole and the pin member in the flat face. Instead of such a structure, the invention may have a structure in which the thrust plate is positioned by using the flat face of another support surface as reference.

Claims

1. A scroll compressor comprising: a compression unit including a movable scroll made up by forming a vortical wrap in an end wall and a similar fixed scroll, and being capable of carrying out compression along with an orbiting movement of the movable scroll with the wraps of the scrolls engaged with each other;

a movable-scroll receiving support surface formed on a back-face side of the end wall of the movable scroll and including a flat face opposite to the back face of the end wall; and

a plurality of thrust plates that are scattered in the support surface along a circumferential direction of the movable scroll, slidably supports the back face of the end wall of the movable scroll, and receives a thrust load from the movable scroll, wherein:

the thrust plates are fixed onto the flat face of the support surface so as to be supported with the flat face by using the flat face as reference.

2. The scroll compressor according to claim 1, wherein each of the thrust plates has a projection protruding toward the support surface; the support surface has a hole that opens toward the corresponding thrust plate; and each of the thrust plates is fixed onto the support surface by interfitting the corresponding projection into the corresponding hole.

3. The scroll compressor according to claim 1, wherein the support surface has a projection protruding toward the corresponding thrust plate; each of the thrust plates has a hole that opens toward the support surface; and each of the thrust plates is fixed onto the support surface by interfitting the corresponding projection into the corresponding hole.