Compressor

Abstract

A compressor has a front housing, a rear housing, a plurality of bolts, and a rigid plate. The rear housing is connected to the front housing. The bolts connect the front housing and the rear housing in an axial direction. The rigid plate is disposed between an axial end surface of one of the front and rear housings and heads of the bolts. The front housing and the rear housing are connected by the bolts via the rigid plate.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a compressor and more particularly to a compressor that suppresses deformation of a thrust surface receiving thrust force inside a housing of the compressor.

[0002] FIG. 5 shows a structure of a conventional swash plate type compressor. A front housing 1 and a rear housing 2 are secured by bolts 4 via a gasket 3. The front housing 1 and the rear housing 2 constitute a housing 5 of the compressor. A step 6 is formed inside the front housing 1. A retainer plate 7, a discharge valve plate 8, a valve plate 9, a suction valve plate 10 are fitted into the front housing 1, so as to contact with the step 6. A suction chamber 12 and a discharge chamber 13 are defined between the retainer plate 7 and a front end wall 11 of the front housing 1 such that the suction chamber 12 and the discharge chamber 13 are separated by a separating wall 14.

[0003] A cylinder block 15 is fitted into the front housing 1 so as to contact with the suction valve plate 10. The cylinder block 15 is secured to the front housing 1 by bolts 16. A drive shaft 17 is rotatably supported by the cylinder block 15, the front housing 1 and the rear housing 2. The one end of the drive shaft 17 protrudes outwardly from the front housing 1, and connects with a driving source, such as an engine or a motor of a vehicle, which is not shown. In the rear housing 2, a lug plate 18 as a rotary support member is secured to the drive shaft 17, and a swash plate 19 is connected with the lug plate 18. The drive shaft 17 extends through a through hole, which is formed through the center of the swash plate 19. A pair of guide pins 20 extending from the swash plate 19 is slidably fitted into a pair of guide holes 21 formed on the lug plate 18. The swash plate 19 integrally rotates with the drive shaft 17 by connecting the guide pins 20 and the guide holes 21. The swash plate 19 is slidably tiltably supported by the drive shaft 17 so as to slide in an axial direction of the drive shaft 17. The lug plate 18 is rotatably supported by a thrust bearing 22, which is disposed on an inner wall of the rear end of the rear housing 2.

[0004] The cylinder block 15 forms a plurality of cylinder bores 23 surrounding the drive shaft 17, and each cylinder bore 23 slidably accommodates each associated piston 24. Each piston 24 is coupled to the periphery of the swash plate 19 through a pair of shoes 25. As the swash plate 19 integrally rotates with the drive shaft 17, each piston 24 reciprocates in the axial direction of the drive shaft 17 in the associated cylinder bore 23 through shoes 25.

[0005] However, the bolts 4 connecting the front housing 1 and the rear housing 2 are arranged in the vicinity of a thrust bearing 22. As the thrust surface of the inner wall of the rear end of the rear housing 2 deforms due to the bolts 4, the deformation of the thrust surface causes an eccentric load to act on the thrust bearing 22. With a consequence of a noise during an operation of the compressor and shortened durability of the thrust bearing 22.

[0006] Particularly, when carbon dioxide is used as refrigerant gas, pressure in the compressor relatively increases. Therefore, the bolts 4 need to be further firmly fastened. However, in such a state, the eccentric load tends to act on the thrust bearing 22.

SUMMARY OF THE INVENTION

[0007] The present invention addresses the above-mentioned problems traceable to an eccentric load by suppressing deformation of a thrust surface of an inner wall of a housing in a compressor.

[0008] In accordance with the present invention, a compressor has a front housing, a rear housing, a plurality of bolts, and a rigid plate. The rear housing is connected to the front housing. The bolts connect the front housing and the rear housing in an axial direction. The rigid plate is disposed between an axial end surface of one of the front and rear housings and heads of the bolts. The front housing and the rear housing are connected by the bolts via the rigid plate.

[0009] According to the present invention, since connecting force of the bolts is equally added on the end surface of one of the front and rear housings via the rigid plate, deformation of the thrust surface is inhibited.

[0010] Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWING

[0011] The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

[0012] FIG. 1 is a longitudinal cross-sectional view of a compressor according to a first embodiment of the present invention;

[0013] FIG. 2 is a rear elevation of a compressor illustrated in FIG. 1;

[0014] FIG. 3 is a rear elevation of a compressor according to a second embodiment;

[0015] FIG. 4 is a rear elevation of a compressor according to a third embodiment; and

[0016] FIG. 5 is a longitudinal cross-sectional view of a compressor of a conventional art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A first embodiment of the present invention will now be described with reference to FIGS. 1 and 2. FIG. 1 shows a structure of a variable displacement compressor according to the first embodiment of the present invention. A front housing 1 and a rear housing 26, which are made of aluminum, are connected via a gasket 3. In this manner, a housing 27 is constructed. A rigid plate 28, which is made of iron, is annular in shape. The rigid plate 28 is disposed on the rear end surface of the rear housing 26. The rigid plate 28 has a bearing surface for bolts 4, and the bolts 4 extends through the rigid plate 28 and the rear housing 26 and is screwed on the front housing 1. As shown in FIG. 2, a plurality of bolts 4 is disposed in equiangular positions on an identical circumference. Thereby, the front housing 1 and the rear housing 26 are connected in an axial direction of the drive shaft 17.

[0018] Other components of the compressor of the present invention are similar to those in the conventional art shown in FIG. 5. A step 6 is formed inside the front housing 1. A retainer plate 7, a discharge valve plate 8, a suction valve plate 10 and a valve plate 9 are fitted into the front housing so as to contact with the step 6. A suction chamber 12 and a discharge chamber 13 are defined between the retainer plate 7 and a front end wall 11 of the front housing 1 such that the suction chamber 12 and the discharge chamber 13 are separated by a separating wall 14.

[0019] A cylinder block 15 is fitted into the front housing 1 so as to contact with the suction valve plate 10. The cylinder block 15 is secured to the front housing 1 by bolts 16. A drive shaft 17 is rotatably supported by the cylinder block 15, the front housing 1 and the rear housing 26. The one end of the drive shaft 17 protrudes outwardly from the front housing 1, and is connected with a driving source, such as an engine or a motor of a vehicle, which is not shown in FIG. 4 in the rear housing 26. A lug plate 18 is secured to the drive shaft 17, and a swash plate 19 is connected with the lug plate 18. The drive shaft 17 extends through a through hole, which is formed through the center of the swash plate 19. A pair of guide pins 20 extending from the swash plate 19 is slidably fitted into a pair of guide holes 21 formed on the lug plate 18. The swash plate 19 integrally rotates with the drive shaft 17 by connecting the guide pins 20 and the guide holes 21. The swash plate 19 is slidably tiltably supported by the drive shaft 17 so as to slide in an axial direction of the drive shaft 17. The lug plate 18 is rotatably supported by a thrust bearing 22, which is disposed on an inner wall of the rear end of the rear housing 26.

[0020] The cylinder block 15 forms a plurality of cylinder bores 23 surrounding the drive shaft 17, and each cylinder bore 23 slidably accommodates each associated piston 24. Each piston 24 is coupled to the periphery of the swash plate 19 through a pair of shoes 25. As the swash plate 19 integrally rotates with the drive shaft 17, each piston 24 reciprocates in the axial direction of the drive shaft 17 in the associated cylinder bore 23 through shoes 25.

[0021] As mentioned above, the front housing 1 and the rear housing 26 are secured by a plurality of bolts 4 via the annular rigid plate 28. Thereby, force tightening each bolt 4 is dispersed, and is equally acted on the rear end surface of the rear housing 26. Therefore, deformation of an inner wall of the rear end of the rear housing 26, that is, deformation of a thrust surface, is suppressed, thus inhibiting an eccentric load from acting on a thrust bearing 22.

[0022] In the compressor shown in FIG. 1, seven cylinder bores 23 are defined in a cylinder block 15 in equiangular positions, and the front housing 1 and the rear housing 26 are connected by seven bolts 4 as shown in FIG. 2. However, the number of the bolts 4 is not limited. As the number of bolts 4 increases, the force tightening the bolts 4 is effectively dispersed. Therefore, deformation of the thrust surface is effectively inhibited.

[0023] All the bolts 4 do not need to be positioned on one rigid plate 28. According to the second embodiment, the rigid plate 28 may be divided into some pieces as shown in FIG. 3, and each rigid plate 28 supports the associated heads of the bolts 4.

[0024] Also, the rigid plate 28 used in the above embodiment is annular in shape, however, the shape of the rigid plate 28 is not limited. According to the third embodiment, if an end surface of a housing disposing the rigid plate is flat, the rigid plate may be disk-shaped, and a plurality of bolts may be positioned in equiangular positions on an identical circumference, as shown in FIG. 4.

[0025] In addition, since the rigid plate 28 is disposed on the rear end surface of the rear housing 26 in the above embodiment, the thrust bearing 22 is disposed on the inner wall of the rear end of the rear housing 26. However, the rigid plate should be disposed on an end surface of a front housing if a compressor has a thrust bearing disposed on an inner wall of a front end of the front housing 1.

[0026] As described above, the rigid plate is disposed between one of the front and rear housings and heads of the bolts. The front housing and the rear housing are connected by the bolts via the rigid plate. Thereby, force tightening each bolt equally acts on the end surface of one of the front and rear housings, with a consequence of suppressed deformation of the thrust surface of the housing. Accordingly, a noise during the operation of the compressor and shortened durability of the thrust bearing due to the deformation of the thrust bearing may be inhibited. In other words, the force tightening the bolts may be increased without any trouble so that the present invention is effective especially when carbon dioxide is used as refrigerant gas.

[0027] The present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.

Claims

1. A compressor comprising,

a front housing;

a rear housing connected to the front housing;

a plurality of bolts connecting the front housing and the rear housing in an axial direction; and

a rigid plate disposed between an axial end surface of one of the front and rear housings and heads of said bolts; and

wherein the front housing and the rear housing are connected by said bolts via said rigid plate.

2. The compressor according to claim 1, wherein said rigid plate is annular in shape, and said bolts are positioned on the circumference of said rigid plate.

3. The compressor according to claim 2, wherein said rigid plate is annular in shape, and said bolts are positioned substantially in equiangular positions on the circumference of said rigid plate.

4. The compressor according to claim 2, wherein said rigid plate is annular in shape, and said rigid plate is formed in one piece.

5. The compressor according to claim 2, wherein said rigid plate is annular in shape, and said rigid plate is constituted of a plurality of plates, and each plate is screwed by a plurality of bolts.

6. The compressor according to claim 1, wherein said rigid plate is disk-shaped, and said bolts are positioned on the circumference of said rigid plate.

7. The compressor according to claim 1, wherein refrigerant gas used in the compressor is carbon dioxide.

8. The compressor according to claim 1, wherein the compressor is a swash plate type.

9. The compressor according to claim 1, wherein the compressor is a variable displacement type.