JPH1018971A - Piston compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the whirling of the driving shaft of a piston compressor by elevating the flexural resonance point of the driving shaft. SOLUTION: A driving shaft 17 is rotatably supported in a housing 11 by means of a pair of radial bearings 18A and 18B, and a cam plate 24 is mounted around the driving shaft 17 at the intermediate portion thereof. The rotation of the driving shaft 17 reciprocates a piston 21 through the cam plate 24 for effecting compression. The driving shaft 17 is shaped to have its maximum diameter at its portion 17b corresponding to the front radial bearing 18A, to thereby improve the rigidity thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston type compressor used in, for example, a vehicle air conditioner, and more particularly to a drive shaft and a supporting structure thereof.

[0002]

2. Description of the Related Art Generally, in a piston type compressor,
A drive shaft is rotatably supported in the housing via a pair of radial bearings. A cam plate is provided at an intermediate portion of the drive shaft, and a thrust bearing is interposed between the cam plate and the housing. A plurality of cylinder bores are formed in a cylinder block constituting a part of the housing, and a piston is accommodated in each cylinder bore so as to be able to reciprocate. Then, a part of the cam plate is moored to each piston, and the rotation of the drive shaft causes the piston to reciprocate via the cam plate, thereby performing the compression action of the refrigerant gas.

In this type of piston type compressor, a cam plate is mounted on a drive shaft by, for example, press fitting. Since the compression reaction force acting on the piston acts on the drive shaft via the cam plate, the cam plate needs to be firmly mounted on the drive shaft. For this reason, in the conventional piston type compressor, for example, as shown in FIG. 3, the outer diameter D1 of the fitting portion 41a corresponding to the cam plate 42 of the drive shaft 41 is formed to be the maximum diameter. Thereby, the contact area of the fitting portion 41a with the cam plate 42 is increased, and the adhesion between the two is improved. The drive shaft 41 is supported by a pair of front and rear radial bearings 43 and 44.

[0004]

However, as shown in FIG. 3, in this conventional piston type compressor, the outer diameter D2 of the support portion 41b corresponding to the front radial bearing 43 of the drive shaft 41 is equal to the cam diameter. Plate 42
Is smaller than the outer diameter D1 of the fitting portion 41a. For this reason, the drive shaft 41 is
When it is rotationally driven through the shaft, there is a possibility that the rigidity of the supporting portion 41b tends to be insufficient. This support part 41
In the state where the rigidity of b is insufficient, the bending resonance point of the drive shaft 41 is low, and the drive shaft 41 easily whirls as shown in FIG. Then, there is a problem that rattling or side contact occurs in the clutch 45, which may cause noise and vibration, damage to the clutch 45, and the like.

[0005] The present invention has been made by paying attention to such problems existing in the prior art. An object of the present invention is to provide a piston-type compressor that can raise the bending resonance point of the drive shaft and is less likely to whirl around the drive shaft.

[0006]

In order to achieve the above object, in the invention of the piston type compressor according to the first aspect,
A drive shaft is rotatably supported in the housing via a pair of radial bearings, a cam plate is disposed at an intermediate portion of the drive shaft, and a thrust bearing is interposed between the cam plate and the housing. A plurality of cylinder bores are formed in a cylinder block constituting a part of the housing so as to extend in parallel with the drive shaft, and a piston is inserted in the cylinder bore so as to be able to reciprocate. The piston type compressor, which is operatively connected to a drive source and reciprocates the piston through the cam plate by rotation of the drive shaft to perform a compression action, wherein the drive shaft includes a front-side radial bearing. The corresponding portion is formed so as to have a maximum diameter.

According to a second aspect of the present invention, in the piston type compressor according to the first aspect, the front-side radial bearing is constituted by a plain bearing.
According to a third aspect of the present invention, in the piston type compressor according to the first or second aspect, the cylinder blocks are configured to form a pair at the front and rear, and the cylinder bores are formed so as to face each cylinder block front and rear, A double-headed piston is inserted into the cylinder bore, and a cam plate is anchored at an intermediate portion of the piston.

[0008] In the invention described in claim 4, claims 1 to 3 are provided.
In the piston type compressor according to any one of the above, the housing and the pressure receiving seat of the cam plate that are in contact with the front-side thrust bearing are formed in a planar shape.

According to the fifth aspect of the present invention, the first to fourth aspects are provided.
In the piston type compressor according to any one of the above, the front-side thrust bearing is constituted by a plain bearing.

[0010] According to the invention described in claim 6, according to claims 1 to 5,
Wherein the cross-sectional area of the drive shaft is formed such that a portion corresponding to the rear-side radial bearing is smaller than a portion corresponding to the cam plate.

According to a seventh aspect of the present invention, in the piston type compressor according to the sixth aspect, a hole is formed in the center of the rear end of the drive shaft to cut off a portion corresponding to the rear radial bearing. The area is reduced.

Therefore, in the piston type compressor according to the first aspect, the portion corresponding to the front radial bearing of the drive shaft has the maximum diameter, and the rigidity of the portion is improved. For this reason, the bending resonance point of the drive shaft is raised, and whirling during rotation drive of the drive shaft is suppressed.

[0013] In the piston type compressor according to the second aspect, the front radial bearing is constituted by a plain bearing. For this reason, the rigidity of support of the drive shaft by the front radial bearing is improved, and whirling of the drive shaft is suppressed more effectively. Further, the structure of the front-side radial bearing is simplified, and the number of parts can be reduced. further,
The radial bearing on the front side can be downsized in the radial direction of the compressor. For this reason, even if the portion of the drive shaft corresponding to the front-side radial bearing is formed to have a large diameter, the entire housing does not increase in size.

According to a third aspect of the present invention, the piston type compressor has a double-headed piston, and a cam plate is anchored at an intermediate portion of the piston. For this reason, the compression reaction force acts alternately on both ends of the double-headed piston, and even when the ratio of the compression reaction force applied to the front radial bearing via the cam plate and the drive shaft is large, the whirling of the drive shaft is ensured. Is suppressed.

In the piston type compressor according to the fourth aspect, the housing and the pressure receiving seat of the cam plate which are in contact with the front-side thrust bearing are formed in a planar shape. Therefore, the support rigidity of the cam plate in the pressure receiving seat of the housing is improved, and the whirling of the drive shaft is more effectively suppressed.

In the piston type compressor according to the fifth aspect, the front-side thrust bearing is constituted by a plain bearing. For this reason, the support rigidity of the cam plate by the front-side thrust bearing is improved, and whirling of the drive shaft is more effectively suppressed. Further, the structure of the front-side thrust bearing is simplified, and the number of parts can be reduced. further,
The front-side thrust bearing can be reduced in size along the entire length of the compressor, and the entire housing can be reduced in size.

In the piston type compressor according to the present invention, the cross-sectional area of the drive shaft is formed so that a portion corresponding to the rear radial bearing is smaller than a portion corresponding to the cam plate. Therefore, the drive shaft is reduced in weight, and its center of gravity can be set near the center in the longitudinal direction, that is, near the front-side radial bearing. In addition, the drive shaft can be driven to rotate lightly in a stable state, and whirling of the drive shaft is more effectively suppressed, in combination with the operation of the support structure of the front-side thrust bearing having the improved support rigidity. You.

In the piston type compressor according to the present invention, the hole is formed in the center of the rear end of the drive shaft, so that the cross-sectional area of the portion corresponding to the rear radial bearing is reduced. Therefore, the sectional area of the portion corresponding to the rear radial bearing can be reduced by a simple structure without reducing the diameter of the portion corresponding to the rear radial bearing of the drive shaft. In addition, a sufficient contact area between the rear radial bearing and the drive shaft can be ensured, and the rigidity of the drive shaft supported by the rear radial bearing does not decrease.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described.
A description will be given based on FIG.

As shown in FIG. 1, a pair of cylinder blocks 11 constituting a part of the housing are joined to each other at opposite edges. The front housing 12, which also forms a part of the housing, is a cylinder block 1
1 is joined to the front end face via a valve plate 13. A rear housing 14, which also forms a part of the housing, is joined to the rear end surface of the cylinder block 11 via a valve plate 13.

A plurality of through bolts 15 are passed from the front housing 12 through the two cylinder blocks 11 and the valve plate 13 to screw holes 16 in the rear housing 14.
Is screwed into. Then, the front housing 12 and the rear housing 14 are
, The cylinder block 1 via both valve plates 13
1 are fastened and fixed to both end faces.

The drive shaft 17 is rotatably supported at the center of the cylinder block 11 and the front housing 12 via a pair of radial bearings 18A and 18B. A lip seal 19 is interposed between the outer periphery of the front end of the drive shaft 17 and the front housing 12. The drive shaft 17 is operatively connected to an external drive source such as a vehicle engine via a clutch (not shown), and is driven to rotate by the external drive source.

A plurality of cylinder bores 20 extend in parallel with the drive shaft 17 so that each cylinder block 1
1 are formed at predetermined intervals on the same circumference between both end portions. The double-headed piston 21 is provided with each cylinder bore 2
0 between the two end faces and the valve plate 13 between the cylinder bores 20.
A compression chamber 22 is formed therein.

The crank chamber 23 is defined in the middle of the cylinder blocks 11. The swash plate 24 as a cam plate is fitted and fixed to the drive shaft 17 in the crank chamber 23, and its outer peripheral portion is moored to an intermediate portion of the piston 21 via a pair of hemispherical shoes 25. And when the drive shaft 17 is rotated,
The piston 21 is reciprocated via the swash plate 24.

A pair of thrust bearings 26A, 26B
Are interposed between both ends of the boss portion 24 a of the swash plate 24 and the inner ends of the cylinder blocks 11. The swash plate 24 is sandwiched and held between the two cylinder blocks 11 via the thrust bearings 26A and 26B. During the operation of the compressor, a compression reaction force acting on the swash plate 24 in the thrust direction causes these thrust bearings 26A,
It is configured to be received by the cylinder block 11 via 26B.

The suction chamber 27 is provided in the front housing 1.
2 and an outer peripheral portion in the rear housing 14 are annularly defined and communicate with the crank chamber 23 through a suction passage 11 a formed in the cylinder block 11 and the valve plate 13. The crank chamber 23 is connected to an external refrigerant circuit via a suction port (not shown). The discharge chamber 28 is formed in an annular shape in the inner peripheral portion inside the front housing 12 and the rear housing 14 and is connected to an external refrigerant circuit via a discharge passage and a discharge port (not shown).

The suction valve mechanism 29 is formed on each of the valve plates 13. When the piston 21 reciprocates, the suction valve mechanism 29 is opened to allow the refrigerant gas in both suction chambers 27 to pass through the suction port 30. It is sucked into the compression chamber 22 of each cylinder bore 20. The discharge valve mechanism 31 is formed on each valve plate 13. When the piston 21 reciprocates, the discharge valve mechanism 31 is opened to allow the refrigerant gas compressed in the compression chamber 22 of each cylinder bore 20 to be discharged to the discharge port 32.
Is discharged to both discharge chambers 28 through the discharge port 28.

Next, the drive shaft 17 and its support structure will be described in detail. The fitting portion 17a of the drive shaft 17 corresponding to the swash plate 24 is formed so as to have a predetermined outer diameter D1, and the contact area of the fitting portion 17a with the boss portion 24a of the swash plate 24 is increased so that the swash plate 24 has a large contact area. To improve the adhesion. Further, the supporting portion 17b corresponding to the front-side radial bearing 18A of the drive shaft 17 has an outer diameter D2 larger than the outer diameter D1 of the fitting portion 17a, and has a maximum diameter over the entire length of the drive shaft 17. Is formed. Thereby, the drive shaft 17
The rigidity of the support portion 17b is improved.

The front-side radial bearing 18A and the rear-side radial bearing 18B are each constituted by a cylindrical plain bearing. Further, each of the front-side thrust bearing 26A and the rear-side thrust bearing 26B is constituted by two annular plain bearings. Moreover, the pressure receiving seat 33 of the cylinder block 11 and the boss 24a of the swash plate 24, which are in contact with the front-side thrust bearing 26A, are formed in a planar shape. The front-side radial bearing 18A and the front-side thrust bearing 26
A, the support rigidity of the support portion 17b of the drive shaft 17 is increased by the configuration of the pressure receiving seat 33 and the boss portion 24a.

The boss 24a of the swash plate 24 and the inner end of the cylinder block 11 which are in contact with the rear thrust bearing 26B are provided with annular pressure receiving seats 34 having different diameters.
Are formed. Then, due to the elastic deformation of the rear thrust bearing 26B interposed between the pressure receiving seats 34, the tolerance of each component of the compressor is absorbed.

Further, a hole 35 is formed at the center of the rear end of the drive shaft 17, and the cross-sectional area of the rear end portion 17c corresponding to the rear radial bearing 18B of the drive shaft 17 is reduced. As a result, the cross-sectional area of the rear end portion 17c is reduced without reducing the outer diameter of the rear end portion 17c of the drive shaft 17, and the fitting portion 1 corresponding to the swash plate 24 is formed.
7a is formed to be smaller than the cross-sectional area.

Next, the operation of the piston type compressor configured as described above will be described. In this piston type compressor, when the drive shaft 17 is rotated by an external drive source such as a vehicle engine (not shown), each piston 21 reciprocates in the cylinder bore 20 via the swash plate 24.
Thereby, the refrigerant gas is supplied from an external refrigerant circuit (not shown)
Similarly, it is introduced into the crank chamber 23 through a suction port (not shown). The refrigerant gas in the crank chamber 23 is supplied to the suction passage 1
It is led to the suction chamber 27 through 1a. With the return operation of the piston 21 from the top dead center position to the bottom dead center position, the suction valve mechanism 29 is opened, and the refrigerant gas in both the suction chambers 27 passes through the suction ports 30 and the compression chambers 22 of the respective cylinder bores 20. Inhaled into. The refrigerant gas in the compression chamber 22 is
With the forward movement from the bottom dead center position to the top dead center position, compression is performed until a predetermined pressure is reached. Then, the compressed refrigerant gas pushes out the discharge valve mechanism 31 and the discharge port 32
And is supplied to the external refrigerant circuit via a discharge passage and a discharge port (not shown).

During operation of the compressor, a compression reaction force acts on both ends of the double-headed piston 21 alternately. The compression reaction force is applied to the cylinder block 1 via the swash plate 24, the drive shaft 17, and the front radial bearing 18A.
1, and acts on the pressure receiving seat 33 of the cylinder block 11 via the swash plate 24 and the front-side thrust bearing 26A.

However, in this piston type compressor, the rigidity of the front support portion 17b of the drive shaft 17 is improved, and the support rigidity of bearings and the like corresponding to the support portion 17b is improved. For this reason, the bending resonance point of the drive shaft 17 rises, and whirling during rotation drive of the drive shaft 17 as shown in FIG. 4 can be suppressed.

The effects that can be expected from the above embodiment will be described below. (A) In the piston type compressor of this embodiment,
Radial bearing 18 on the front side of drive shaft 17
By setting the support portion 17b corresponding to A to the maximum diameter, the rigidity of the portion is improved. For this reason, the bending resonance point of the drive shaft 17 is raised, and the drive shaft 17
Whirling hardly occurs. Therefore, it is possible to prevent the clutch from rattling or causing a one-sided contact with the whirling of the drive shaft 17, thereby causing problems such as generation of noise and vibration and damage of the clutch 45. It can be made less likely to occur.

(B) In the piston type compressor of this embodiment, the front radial bearing 18A is formed of a cylindrical plain bearing. Therefore, the rigidity of the front side radial bearing 18A for supporting the drive shaft 17 can be improved, and the whirling of the drive shaft 17 can be more effectively suppressed.

(C) In the piston type compressor of this embodiment, the front radial bearing 18A is formed of a plain bearing. For this reason, the structure of the radial bearing 18A is simple, the number of parts can be reduced, and the outer diameter of the bearing 18A can be reduced. Therefore, the drive shaft 17
Even if the support portion 17b corresponding to the front-side radial bearing 18A is formed to have a large diameter, it is possible to suppress an increase in the size of the entire housing.

(D) In the piston type compressor of this embodiment, the piston 21 is formed as a double-headed type, and the swash plate 24 is moored at an intermediate portion of the piston 21. Therefore, even when the compression reaction force acts on both ends of the double-headed piston 21 alternately and the ratio of the compression reaction force applied to the front radial bearing 18A via the swash plate 24 and the drive shaft 17 is large, the drive shaft 17 Whirling can be reliably suppressed.

(E) In the piston type compressor of this embodiment, the pressure receiving seat 33 and the swash plate 24 of the cylinder block 11 which are in contact with the front thrust bearing 26A.
Is formed in a planar shape. For this reason,
The support rigidity of the swash plate 24 in the pressure receiving seat 33 of the cylinder block 11 is improved, and the whirling of the drive shaft 17 can be suppressed more effectively.

(F) In the piston type compressor of this embodiment, the front-side thrust bearing 26A is constituted by an annular plain bearing. Therefore, the swash plate 2 formed by the front-side thrust bearing 26A is used.
4 is improved, and the whirling of the drive shaft 17 can be more effectively suppressed.

(G) In the piston type compressor of this embodiment, since the front-side thrust bearing 26A is formed of a plain bearing, the structure of the thrust bearing 26A is simple, and the number of parts can be reduced. The thickness of the bearing 26A can be reduced. For this reason, the whole housing can be reduced in size.

(H) In the piston-type compressor of this embodiment, the cross-sectional area of the rear end portion 17c corresponding to the rear radial bearing 18B of the drive shaft 17 is such that the cross-sectional area of the fitting portion 17a corresponding to the swash plate 24 is reduced. It is formed to be smaller than the area. Therefore, the drive shaft 17
Can be reduced in weight, and the drive shaft 17
Can be set near the center in the longitudinal direction, that is, near the front-side radial bearing 18A. Then, near the center of gravity of the drive shaft 17, the front-side thrust bearing 26 having improved support rigidity is provided.
A is surely supported. Therefore, the drive shaft 17 can be lightly driven to rotate in a stable state, and whirling of the drive shaft 17 is more effectively suppressed.

(I) In the piston type compressor of this embodiment, by forming the hole 35 at the center of the rear end of the drive shaft 17, the cross-sectional area of the rear end portion 17c corresponding to the rear radial bearing 18B is reduced. Have been. Therefore, the cross-sectional area of the rear end portion 17c of the drive shaft 17 can be reduced with a simple structure.

(J) In the piston type compressor of this embodiment, the hole 35 is formed at the center of the rear end portion 17c corresponding to the rear radial bearing 18B of the drive shaft 17. Therefore, without reducing the outer diameter of the rear end portion 17c of the drive shaft 17,
The cross-sectional area of 7c has been reduced. Thus, a sufficient contact area between the rear end portion 17c and the rear radial bearing 18B can be ensured. Therefore, the support rigidity of the drive shaft 17 by the rear radial bearing 18B does not decrease, and the stable drive shaft 17
Of rotation can be obtained.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, similarly to the first embodiment, the outer diameter D2 of the support portion 17b corresponding to the front-side radial bearing 18A of the drive shaft 17 corresponds to the fitting portion 17a corresponding to the swash plate 24. Is larger than the outer diameter D1 of
The drive shaft 17 has a maximum diameter over its entire length. Also,
The pressure receiving seat 33 of the cylinder block 11 and the boss 24 of the swash plate 24 which are in contact with the front-side thrust bearing 26A.
a is formed in a planar shape.

On the other hand, in the second embodiment, the front radial bearing 18A and the rear radial bearing 18B are each constituted by a needle bearing. Furthermore, the front side thrust bearing 2
The 6A and the rear-side thrust bearing 26B are also constituted by needle bearings, respectively.

Even in the case of such a configuration, the rigidity of the front-side support portion 17b of the drive shaft 17 is improved, substantially in the same manner as in the first embodiment described above.
The bending resonance point of No. 7 is raised. Therefore, the drive shaft 1
7 can be suppressed.

The present invention can be embodied with the following modifications. (1) The front-side radial bearing 18A and the front-side thrust bearing 26A are formed of plain bearings as in the first embodiment, and the rear-side radial bearing 18B and the rear-side thrust bearing 26B are formed as follows.
It should be constituted by a needle bearing as in the second embodiment.

(2) Front side radial bearing 1
8A and the rear radial bearing 18B are formed of plain bearings as in the first embodiment, and the front thrust bearing 26A and the rear thrust bearing 26B are formed of needle bearings as in the second embodiment.

(3) A pair of radial bearings 18
A, 18B and a pair of thrust bearings 26A, 26
In B, one arbitrary bearing is constituted by a plain bearing and the other bearing is constituted by a needle bearing.

(4) A pair of radial bearings 18
A and 18B are omitted, and a layer of a material having a stable friction coefficient is formed on the inner peripheral surface of the cylinder block 11 facing the support portion 17b and the rear end portion 17c of the drive shaft 17, so that the drive shaft 17 is connected to the cylinder block 11 to be supported almost directly on the inner peripheral surface.

(5) Rear thrust bearing 26B
The pressure receiving seat 34 of the cylinder block 11 that is in contact with the pressure sensor is formed in a planar shape. (6) The cross-sectional area of the rear end portion 17c is reduced by forming a plurality of concave grooves on the outer periphery of the rear end portion 17c instead of the hole 35 at the rear end center of the drive shaft 17.

Even with such a configuration, it is possible to obtain substantially the same functions and effects as those of the above embodiments. (7) The present invention is embodied in a wave cam plate type double head type piston compressor or a single head type piston type compressor.

[0054]

The present invention is configured as described above, and has the following effects. According to the first aspect of the present invention, the rigidity of the portion of the drive shaft corresponding to the front radial bearing is improved, and the bending resonance point of the drive shaft can be raised. For this reason, it is possible to suppress the occurrence of problems such as noise, vibration, breakage, etc. due to rattling or partial contact of the clutch due to whirling of the drive shaft.

According to the second aspect of the invention, the support rigidity of the front-side radial bearing can be increased, and the whirling of the drive shaft can be suppressed more effectively.

According to the present invention, the structure of the front-side radial bearing can be simplified and downsized. For this reason, even if a portion corresponding to the front-side radial bearing of the drive shaft is formed to have a large diameter, it is possible to suppress an increase in the size of the entire housing.

According to the third aspect of the invention, the compression reaction force acts alternately on both ends of the double-headed piston, and the ratio of the compression reaction force applied to the front-side radial bearing via the cam plate and the drive shaft is reduced. Even when large, the whirling of the drive shaft can be reliably suppressed.

According to the present invention, the support rigidity of the cam plate in the pressure receiving seat that is in contact with the front-side thrust bearing can be improved, and the whirling of the drive shaft can be suppressed more effectively. Can be.

According to the fifth aspect of the invention, the support rigidity of the front-side thrust bearing can be increased, and the whirling of the drive shaft can be suppressed more effectively.

According to the present invention, the structure of the front-side thrust bearing can be simplified and downsized, and the entire housing can be downsized. According to the invention described in claim 6, the weight of the drive shaft can be reduced, and the center of gravity of the drive shaft can be set near the center in the longitudinal direction, that is, near the front-side radial bearing. Therefore, the rotation of the drive shaft can be stabilized, and whirling of the drive shaft can be suppressed more effectively.

According to the seventh aspect of the present invention, a simple structure in which a hole is formed in the center of the rear end of the drive shaft can reduce the cross-sectional area of a portion corresponding to the rear radial bearing.

Further, according to the present invention, the portion of the drive shaft corresponding to the rear-side radial bearing is not reduced in diameter, and the cross-sectional area of the portion is maintained at a predetermined outer diameter while maintaining the supporting rigidity. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a piston type compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a piston type compressor according to a second embodiment of the present invention.

FIG. 3 is a front view showing a drive shaft of a conventional piston type compressor.

FIG. 4 is an explanatory diagram showing a whirling state of the drive shaft.

[Explanation of symbols]

11 ... Cylinder block forming a part of housing
12: a front housing constituting a part of the housing; 14: a rear housing constituting a part of the housing; 17: a drive shaft; 17a: a fitting portion corresponding to a cam plate; 17b: a front radial bearing; Supporting part as corresponding part, 17c
... A rear end portion corresponding to the rear side radial bearing, 18A ... Front side radial bearing, 18
B: rear radial bearing, 20: cylinder bore,
21: double-headed piston, 24: swash plate as cam plate, 26A: front-side thrust bearing, 26B
... Rear thrust bearing, 33, 34 ... Pressure receiving seat, 3
5 ... holes.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Rieko Harada 2-1-1, Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation

Claims (7)

[Claims] A drive shaft is rotatably supported in a housing via a pair of radial bearings, a cam plate is disposed at an intermediate portion of the drive shaft, and a thrust is provided between the cam plate and the housing. A plurality of cylinder bores are formed in the cylinder block forming a part of the housing with a bearing interposed therebetween so as to extend in parallel with the drive shaft, and a piston is inserted into the cylinder bore so as to be able to reciprocate. A piston compressor in which a front side of a shaft is operatively connected to a drive source, and the rotation of the drive shaft reciprocates the piston via the cam plate to perform a compression action. A piston type compressor formed so that the part corresponding to the front radial bearing has the maximum diameter. 2. The piston type compressor according to claim 1, wherein said front side radial bearing is constituted by a plain bearing. 3. The cylinder block is formed so as to form a pair at the front and rear, the cylinder bore is formed so as to oppose each cylinder block at the front and rear, and a double-headed piston is inserted into the cylinder bore, and an intermediate portion of the piston is provided. The piston type compressor according to claim 1 or 2, wherein a cam plate is moored to the portion. 4. The piston type compressor according to claim 1, wherein a pressure receiving seat of the housing and the cam plate which is in contact with the front-side thrust bearing is formed in a flat shape. 5. The piston type compressor according to claim 1, wherein said front-side thrust bearing is constituted by a plain bearing. 6. The drive shaft according to claim 1, wherein a cross-sectional area of the drive shaft is smaller in a portion corresponding to the rear-side radial bearing than in a portion corresponding to the cam plate.
6. The piston type compressor according to any one of 5. 7. The piston type compressor according to claim 6, wherein a hole is formed in the center of the rear end of the drive shaft to reduce a cross-sectional area of a portion corresponding to the rear radial bearing.