JPH09228947A - Piston type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piston type compressor having a thrust bearing structure which can efficiently perform lubrication to prevent easily generating of trouble of wearing, seizure, etc. SOLUTION: Thrust bearings 37, 38 formed by a sheet of circular annular washer 41 are interposed between a boss part 34a of a swash plate 34 and pressure receiving parts 39, 40 of cylinder blocks 11, 12. Both end edges of a pressure receiving surface of the washer 41 are formed in a curved surface such as continuously enlarging a radius of curvature toward the pressure receiving surface, for instance, in a curved surface such as making a sectional shape in a circular arc shape 1/4 an ellipse.

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 thrust bearing structure thereof.

[0002]

2. Description of the Related Art In this type of piston type compressor, a drive shaft is supported inside a housing and a crank chamber is formed. A plurality of cylinder bores are arranged around the drive shaft in a cylinder block forming a part of the housing. A piston is reciprocally housed in the cylinder bore. A cam plate is integrally rotatably attached to the drive shaft. A thrust bearing is interposed between the cam plate and the housing. As the thrust bearing, for example, a rolling bearing in which a roller is interposed between two annular washers, or a slide bearing including only an annular washer is adopted. The thrust load acting on the cam plate is supported by the housing via the thrust bearing.

[0003]

By the way, in recent years, as the performance of a vehicle engine, which is an external drive source of a piston type compressor, has been improved, the compressor is also operated in a higher rotation speed range. It's coming. In addition, the compression reaction force of the piston acting on the cam plate is increasing along with the tendency of increasing the number of cylinders in the compressor. On the other hand, the space in which the compressor can be installed in the engine room is limited, and there is a demand for downsizing of the compressor. Further, in a so-called clutchless type compressor in which the drive shaft is constantly operatively connected to the external drive source, the cam plate is constantly rotated as the drive shaft rotates. Under such circumstances, the load applied to the thrust bearing interposed between the cam plate and the housing is increasing, and the lubrication of the thrust bearing is becoming more important.

An object of the present invention is to provide a piston type compressor having a thrust bearing structure which can efficiently perform lubrication and is less likely to cause problems such as wear and seizure.

[0005]

In order to achieve the above object, in the invention described in claim 1, a thrust bearing is interposed between the cam plate and the housing, and a thrust load acting on the cam plate is provided. In a thrust bearing structure of a piston type compressor, which is supported by a housing through a thrust bearing, the thrust bearing is composed of at least one annular washer, and the inner and outer peripheral sides of a pressure receiving surface of the washer. At least one of the edges has a curved surface whose radius of curvature continuously increases toward the pressure receiving surface.

According to a second aspect of the present invention, in the piston type compressor according to the first aspect, the curved surface has a cross-sectional shape of a quarter arc of an ellipse. Claim 3
In the invention according to claim 2, in the piston type compressor according to claim 2, the flatness ratio based on the ratio of the length of the major axis to the length of the minor axis of the ellipse is 50 to 300.

In the invention described in claim 4, claims 1 to 3 are provided.
In the piston type compressor according to any one of items 1 to 3, the curved surface is formed by buffing or barrel polishing. According to a fifth aspect of the present invention, in the piston type compressor according to any of the first to fourth aspects, the thrust bearing includes a slide bearing including only one washer.

In the invention described in claim 6, claims 1 to 4 are provided.
In the piston type compressor according to any one of items 1 to 3, the thrust bearing includes a rolling bearing in which rolling elements are interposed between a plurality of washers.

In the piston type compressor constructed as described above, the thrust bearing interposed between the cam plate and the pressure receiving seat of the housing is composed of at least one annular washer. The edge of the pressure receiving surface of the washer is formed into a curved surface whose radius of curvature continuously increases toward the pressure receiving surface, for example, a curved surface whose cross-sectional shape is a quarter arc of an ellipse. There is. Therefore, between the pressure receiving surface of the thrust bearing and the cam plate and the pressure receiving seat of the housing that face the pressure receiving surface, a wedge-shaped oil film forming gap is formed that extends toward the center of the pressure receiving surface and contracts. . The lubricating oil dispersed in mist form in the refrigerant gas and the lubricating oil adhering to the surrounding inner wall surface and the like are drawn into the oil film forming gap by the wedge effect accompanying the rotation of the cam plate. And a pressure receiving surface of the thrust bearing,
A dynamic pressure bearing is formed between the cam plate and the pressure receiving seat of the housing to reduce sliding resistance.

Here, the length of the major axis with respect to the length of the minor axis of the ellipse is defined as the flatness. That is, an ellipse having a smaller flatness value is closer to a circle, and an ellipse having a larger flatness value is a flat ellipse. By setting the flatness of the ellipse to be less than 50, the opening width of the maximum opening of the oil film formation gap becomes excessively large, and the oil film pressure generated in the oil film in the oil film formation gap becomes small. . For this reason, the wedge effect for continuously drawing the lubricating oil into the oil film formation gap is difficult to be exhibited, and the lubrication between the pressure receiving surface of the thrust bearing and the pressure receiving seat of the cam plate and the housing is insufficient. There is a risk of becoming apt. On the other hand, if the elliptical flatness is greater than 300, the opening width of the maximum opening of the oil film forming gap becomes too small, and the inlet for drawing in the lubricating oil becomes narrow. For this reason, the lubricating oil is less likely to be drawn in, and there is a possibility that the lubrication tends to be insufficient as in the above case.

On the other hand, in the piston type compressor of the present invention, the flatness of the ellipse is formed to be 50 to 300. Therefore, when the dynamic pressure bearing is configured between the cam plate and the pressure receiving seat of the housing, the opening width of the maximum opening of the oil film forming gap becomes appropriate. Then, the oil film pressure generated in the oil film in the oil film formation gap becomes appropriate, the wedge effect is effectively exhibited, and the lubricating oil is easily drawn into the oil film formation gap.

Further, in the washer, the curved surface of the edge of the pressure receiving surface is formed by buffing or barrel polishing.
Therefore, the curved surface can be formed simultaneously with the finish polishing of the pressure receiving surface, which is advantageous in manufacturing.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, a pair of cylinder blocks 11 and 12 forming a part of the housing are joined at the central portion. A front housing 15 is joined to the front end surface of the cylinder block 11 via a valve plate 13, and a rear housing 16 is joined to the rear end surface of the cylinder block 12 via a valve plate 14. The cylinder blocks 11, 1
2, valve plates 13 and 14, front housing 1
5 and the rear housing 16 are fastened and fixed to each other by a plurality of through bolts 17 to form a compressor housing.

Axial hole 1 of the cylinder blocks 11 and 12
A drive shaft 18 is rotatably supported on the 1a and 12a via radial bearings 19 and 20, respectively. The drive shaft 18 is rotated by an external drive source such as a vehicle engine via a clutch (not shown). A crank chamber 21 is formed in the center of the cylinder blocks 11 and 12.

A plurality of cylinder bores 22 are provided around the drive shaft 18 in the cylinder blocks 11 and 12.
Are formed so as to be parallel to each other, and a double-headed piston 23 is accommodated therein so as to be reciprocally movable.

Annular suction chambers 24 and 25 are formed on the outer peripheral sides of the front housing 15 and the rear housing 16, and annular discharge chambers 26 and 27 are defined on the center side. The suction chambers 24 and 25 include the valve plate 13,
The cylinder chamber 22 is communicated with the crank chamber 21 through suction passages 30 and 31 through suction valve mechanisms 28 and 29 formed in the cylinder 14. The crank chamber 21 is connected to an external refrigerant circuit via a suction flange (not shown) formed in the cylinder blocks 11 and 12. Further, the discharge chambers 26 and 27 are the valve plate 1
The external refrigerant circuit is communicated with the inside of the cylinder bore 22 through the discharge valve mechanisms 32 and 33 formed in Nos. 3 and 14 through a discharge passage and a discharge flange (not shown). The suction valve mechanisms 28, 29 are composed of suction valves 28a, 29a and suction ports 28b, 29b. The discharge valve mechanisms 32 and 33 are composed of suction valves 32a and 33a and suction ports 32b and 33b.

At the middle outer peripheral portion of the drive shaft 18,
A swash plate 34 as a cam plate is attached so as to rotate integrally with the drive shaft 18. The double-headed piston 23 is moored to the swash plate 34 via shoes 35 and 36, and the double-headed piston 23 is reciprocated in the cylinder bore 22 by the rotation of the swash plate 34. The boss portion 34a of the swash plate 34 is supported by thrust bearings 37 and 38 on pressure receiving seats 39 and 40 formed on the front and rear inner wall surfaces of the cylinder blocks 11 and 12, respectively.

The thrust bearings 37, 38 are sliding bearings consisting of an annular washer 41 only. As shown in FIGS. 2 and 3, the washer 41 has a curved surface 43 such that both inner and outer edges of the pressure receiving surface 42 have a continuously increasing radius of curvature toward the pressure receiving surface 42, for example, an elliptical cross section 4
It is formed into a curved surface that forms a circular arc shape. Here, the flatness ratio, which is the ratio of the length of the major axis to the length of the minor axis of this ellipse, is 50 to 300, preferably 70 to 2.
50, and more preferably 80 to 200. Note that, for ease of understanding, in FIG. 3, a quarter arc of an ellipse forming the cross-sectional shape of the curved surface 43 at both ends of the pressure receiving surface 42 is drawn with a small flatness. The length of the minor axis of the ellipse in the actual washer 41 is several μm.
~ About several tens of μm

In the piston type compressor constructed as described above, when the drive shaft 18 is rotated by an external drive source such as a vehicle engine, the swash plate 34 in the crank chamber 21 is rotated.
Is rotated, and the plurality of double-headed pistons 23 are reciprocated in the cylinder bore 22 via the shoes 35 and 36. The refrigerant gas guided from the suction flange (not shown) to the crank chamber 21 by the movement of the double-headed piston 23 passes through the suction passages 30 and 31 from the crank chamber 21 and the suction chambers 24 and 25.
It is led to. In the suction stroke of the double-headed piston 23 from the top dead center to the bottom dead center, the suction valves 28a and 29a are opened, and the refrigerant gas in the suction chambers 24 and 25 passes through the suction ports 28b and 29b into the cylinder bore 22. Inhaled. Next, in the compression / discharge stroke in which the double-headed piston 23 moves from the bottom dead center to the top dead center, the refrigerant gas in the cylinder bore 22 is compressed. Then, when the refrigerant gas reaches a predetermined pressure, the high-pressure compressed refrigerant gas pushes the discharge valves 32a, 33a away, and passes through the discharge ports 32b, 33b to discharge chamber 2
6 and 27 are discharged. Further, the compressed refrigerant gas in the discharge chambers 26 and 27 is supplied to a condenser, an expansion valve, and an evaporator, which form an external refrigerant circuit (not shown), through a discharge passage (not shown), and is used for air conditioning in the vehicle compartment.

According to the present embodiment configured as described above, the following effects are obtained. (A) Thrust bearings 37 and 38 interposed between the boss portion 34a of the swash plate 34 and the pressure receiving seats 39 and 40 of the cylinder blocks 11 and 12 are composed of a single annular washer 41. . Both end edges of the pressure receiving surface 42 of the washer 41 are
It is formed into a curved surface 43 whose radius of curvature continuously increases toward the pressure receiving surface 42, for example, a curved surface whose cross-sectional shape is a quarter arc of an ellipse. Therefore, as shown in FIG. 3, the pressure receiving surface 42 of the washer 41 and the pressure receiving surface 42
The boss portion 34a and the pressure receiving seats 39 and 40 facing each other.
A wedge-shaped oil film formation gap 44 is formed between the and, which extends toward the center of the pressure receiving surface 42 and contracts.
Due to the wedge effect accompanying the rotation of the swash plate 34, the lubricating oil dispersed in mist form in the refrigerant gas and the lubricating oil adhering to the surrounding inner wall surface and the like are drawn into the oil film formation gap 44. The pressure receiving surface 42 of the washer 41 and the boss portion 34a
Further, a dynamic pressure bearing is formed between the pressure receiving seats 39 and 40 and the sliding resistance between them is reduced, and the relative rotation of the swash plate 34 with respect to the cylinder blocks 11 and 12 becomes stable.

Therefore, problems such as seizure in the thrust bearings 37 and 38 are less likely to occur, and wear is reduced. Moreover, power loss during operation is reduced. Further, as compared with the case where rolling bearings are used for the thrust bearings 37 and 38, the number of parts can be reduced, the manufacturing cost can be reduced, and rolling noise can be eliminated to reduce noise during operation. .

(B) The washer 41 is formed so that the flatness of the ellipse forming the cross section of the both end edges is 50 to 300. Here, if the flatness of the ellipse is set to be less than 50, the opening width of the maximum opening of the oil film forming gap 44 becomes excessively large, and the oil film pressure generated in the oil film in the oil film forming gap 44 is small. Will be things. Therefore, the wedge effect for continuously drawing the lubricating oil into the oil film forming gap 44 is hard to be exerted, and the pressure receiving surface 4 of the washer 41 is difficult to be exhibited.
2, the boss portion 34a of the swash plate 34, and the cylinder block 1
There is a possibility that lubrication between the pressure receiving seats 39 and 40 of 1 and 12 may be insufficient. On the other hand, if the elliptical flatness is greater than 300, the opening width of the maximum opening of the oil film forming gap 44 becomes too small, and the inlet for drawing the lubricating oil becomes narrow. For this reason, the lubricating oil is less likely to be drawn in, and there is a possibility that the lubrication tends to be insufficient as in the above case. On the other hand, in the washer 41 of this embodiment, the boss portion 34a and the pressure receiving seat 39,
When the dynamic pressure bearing is formed between the oil film forming gap 40 and the pressure bearing 40, the opening width of the maximum opening of the oil film forming gap 44 becomes appropriate. Then, the oil film pressure generated in the oil film in the oil film formation gap 44 becomes appropriate, the wedge effect is effectively exhibited, and the lubricating oil is easily drawn into the oil film formation gap 44. Therefore, the thrust bearings 37, 38
The seizure resistance and wear resistance of the above are further improved, and the power loss is further reduced.

(C) The washer 41 has a pressure receiving surface 42.
The curved surfaces 43 at both edges are formed by buffing or barrel polishing. Therefore, the curved surface 43 can be formed simultaneously with the finish polishing of the pressure receiving surface 42, which is advantageous in manufacturing.

(Second Embodiment) Next, a second embodiment of the present invention will be described focusing on parts different from the first embodiment.

In the second embodiment, as shown in FIG. 4, rolling is performed as thrust bearings 51, 52 between the boss portion 34a of the swash plate 34 and the pressure receiving seats 39, 40 of the cylinder blocks 11, 12. Needle bearing 53 as a bearing
Is interposed. The needle bearing 53 includes an inner race 54 and an outer race 55 as washers, and a needle roller 56 as a rolling element interposed therebetween.
It is composed of The inner race 54 and the outer race 55 have substantially the same shape as the washer 41 described in the first embodiment shown in FIGS. 2 and 3. That is, the two end edges of the pressure receiving surface 42 of the two races 54 and 55 have curved surfaces 43 whose curvature radii continuously increase toward the pressure receiving surface 42, for example, the cross-sectional shape is a quarter of an ellipse.
It is formed into a curved surface that makes an arc. Moreover, the flatness of the ellipse is 50 to 300, preferably 70 to 25.
0, and more preferably 80 to 200.

According to the present embodiment configured as described above, the following effects can be obtained. (A) Between the pressure receiving surface 42 of the two races 54, 55 and the boss portion 34a and the pressure receiving seats 39, 40 facing the pressure receiving surface 42, the same pressure receiving surface as in the first embodiment is provided. A wedge-shaped oil film formation gap 44 is formed that extends toward the center of the surface 42 and contracts. Due to the wedge effect accompanying the rotation of the swash plate 34, the lubricating oil dispersed in mist form in the refrigerant gas and the lubricating oil adhering to the surrounding inner wall surface and the like are drawn into the oil film formation gap 44. A large amount of lubricating oil is present in the thrust bearings 51, 52, the sliding resistance in the thrust bearings 51, 52 is reduced, and the swash plate 3 for the cylinder blocks 11, 12 is reduced.
The relative rotation of 4 becomes stable. Therefore, problems such as seizure in the thrust bearings 51 and 52 are less likely to occur, and wear is reduced. Moreover,
Power loss during operation is reduced.

The present invention can be modified and embodied as follows. (1) In the first embodiment, the number of washers 41 forming the thrust bearings 37, 38 other than those described in the above embodiment, for example, two or more, is interposed.

(2) In each of the above embodiments, the swash plate 3
4. The boss portion 34a of No. 4 and the pressure receiving seats 39, 40 of the cylinder blocks 11, 12 are provided with annular projections having mutually different diameters, and the washer 41 or the needle bearing 53 is interposed between the annular projections. .

(3) In each of the above embodiments, the washer 4
The cross-sectional shape of the curved surface 43 at the end edge of the pressure receiving surface 42 is a shape other than those described in the above embodiment, for example, a parabola, an involute curve, a cycloid curve, a part of a spiral line, etc., whose curvature radius changes continuously To do this.

(4) The present invention is embodied in a wave cam plate type double-headed piston type compressor. Even with such a configuration, it is possible to obtain substantially the same operational effects as the operational effects described in the first embodiment.

(5) The present invention is embodied in a thrust bearing which is interposed between a front surface of a rotary support member which rotates integrally with a swash plate of the single-head piston type compressor and an inner wall surface of the front housing. thing.

With such a structure, it is particularly effective for reducing the sliding resistance of the thrust bearing in the crank chamber where the lubrication environment is severe, in a variable capacity compressor in which the crank chamber does not form a part of the intake passage. is there. Further, it is more effective in a so-called clutchless type compressor in which the drive shaft is always operatively connected to the external drive source.

[0034]

As described above in detail, the present invention has the following excellent effects. The thrust bearing interposed between the cam plate and the pressure receiving seat of the housing is composed of at least one annular washer. The edge of the pressure receiving surface of the washer is formed into a curved surface whose radius of curvature continuously increases toward the pressure receiving surface. Therefore, between the pressure receiving surface of the thrust bearing and the cam plate and the pressure receiving seat of the housing that face the pressure receiving surface, a wedge-shaped oil film forming gap is formed that extends toward the center of the pressure receiving surface and contracts. . Lubricating oil is drawn into the oil film forming gap to form a dynamic pressure bearing between the cam plate and the pressure receiving seat of the housing. Then, the sliding resistance in the thrust bearing is reduced, and the relative rotation of the cam plate with respect to the housing becomes stable. Therefore, problems such as seizure in the thrust bearing are less likely to occur and wear is reduced. Moreover, power loss during operation is reduced.

The curved surface is formed so that the flatness of a quarter arc of an ellipse forming the cross-sectional shape is in the range of 50 to 300. Therefore, the opening width of the maximum opening of the oil film forming gap becomes appropriate for constituting the dynamic pressure bearing, and the wedge effect is effectively exhibited, and
Lubricating oil is easily drawn into the gap. Therefore, seizure resistance and wear resistance of the thrust bearing are further improved, and power loss is further reduced.

Further, in the washer, the curved surface of the edge of the pressure receiving surface is formed by buffing or barrel polishing.
Therefore, the curved surface can be formed simultaneously with the finish polishing of the pressure receiving surface, which is advantageous in manufacturing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a piston type compressor according to a first embodiment.

FIG. 2 is a perspective view showing a washer that constitutes a thrust bearing.

FIG. 3 is an enlarged partial sectional view showing a main part of FIG. 1;

FIG. 4 is a partial cross-sectional view showing a main part of a piston type compressor according to a second embodiment.

[Explanation of symbols]

11, 12 ... Cylinder block forming part of housing, 15 ... Front housing forming part of housing, 16 ... Rear housing forming part of housing, 37, 38, 51, 52 ... Thrust bearing, 41 …
Washers, 43 ... Curved surfaces, 53 ... Needle bearings as rolling bearings, 54 ... Inner races as washers, 55 ... Outer races as washers, 56 ... Needle rollers as rolling elements.

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

Claims (6)

[Claims] 1. A piston type compressor in which a thrust bearing is interposed between a cam plate and a housing, and a thrust load acting on the cam plate is supported by the housing via the thrust bearing. Is composed of at least one annular washer, and at least one of the inner and outer edges of the pressure receiving surface of the washer has a curved surface whose radius of curvature continuously increases toward the pressure receiving surface. Piston compressor that makes up. 2. The piston type compressor according to claim 1, wherein the cross-sectional shape of the curved surface is formed in a quarter arc shape of an ellipse. 3. The piston type compressor according to claim 2, wherein the flatness ratio based on the ratio of the length of the major axis to the length of the minor axis of the ellipse is 50 to 300. 4. The piston type compressor according to claim 1, wherein the curved surface is formed by buffing or barrel polishing. 5. The piston type compressor according to claim 1, wherein the thrust bearing includes a slide bearing formed of only one of the washers. 6. The piston type compressor according to claim 1, wherein the thrust bearing includes a rolling bearing in which rolling elements are interposed between a plurality of washers.