JPH10220347A - Variable capacity compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable capacity compressor, which can reduce possibility that the peripheral edge of a shoe is bitten into a space between a cam plate and a piston, can secure the lubrication of a sliding part between the shoe and the piston, and is inexpensive. SOLUTION: A piston 21 is connected around the periphery of a cam plate 19 through a pair of approximately semisphere shoes 22. The piston 21 is reciprocated through the cam plate 19 by the rotation of a driving shaft, and refrigerant gas compression operation is carried out by delivery capacity according to the inclination angle of the cam plate 19. Cut parts 22c are formed around the peripheral edges of the shoes 22. These cut parts 22c are formed in a manner that, when the at least cam plate 19 is displaced in a condition of the maximum inclination angle, the peripheral edges of the shoes 22 are positioned on the inner side of the spherical receiving seat 21c of the piston 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor used in, for example, a vehicle air conditioner.

[0002]

2. Description of the Related Art Conventionally, as a variable displacement compressor used for a vehicle air conditioner or the like, for example, Japanese Unexamined Patent Publication No. 61-171886 is known.
Japanese Patent Application Laid-Open Publication No. H10-260, 1988 discloses a configuration known as such. In this conventional configuration, a crank chamber is formed inside a housing, and a drive shaft is rotatably supported. 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. In the crank chamber, a cam plate is mounted on the drive shaft so as to be integrally rotatable and swingable, and each piston is moored around the cam plate via a pair of substantially hemispherical shoes. The piston is reciprocated via the cam plate by the rotation of the drive shaft, and the compression operation of the refrigerant gas is performed with a discharge capacity corresponding to the inclination angle of the cam plate.

[0003]

However, in this conventional variable displacement compressor, a spherical portion is formed on the outer surface of each shoe and a flat portion is formed on the inner surface, and a boundary between the spherical portion and the flat portion is formed. The outer peripheral edge is formed at an acute angle.
Then, in a state where the flat portions of both shoes are joined to the outer surfaces on both sides of the cam plate, a spherical body is substantially formed by the spherical portions of both shoes. For this reason, when the piston is reciprocated via the cam plate by the rotation of the drive shaft, there is a problem that the sharp outer peripheral edge of the shoe may be bitten into the gap between the cam plate and the piston.

In the above-described conventional variable displacement compressor,
In order to control the displacement, it is necessary to precisely control the pressure in the crank chamber, and the crank chamber is not part of the suction passage. That is, the refrigerant gas containing sufficient oil is directly sucked into each cylinder bore from the suction chamber in the rear housing.

Therefore, in addition to the oil injected at the time of assembling, the oil supplied to the crank chamber is limited to the following two types. That is, one is accompanied by the blow-by gas supplied through the gap between each cylinder bore and the piston, and the other is the refrigerant gas supplied through the air supply passage when the capacity control valve is opened. It is accompanied by Therefore, if the amount of oil staying in the crank chamber decreases for some reason, there is a possibility that lubrication of sliding portions such as between the shoe and the piston and between the shoe and the cam plate tends to be poor.

Further, in order to secure the slidability of the sliding portion between the shoe and the cam plate under severe lubrication conditions, expensive surface treatment such as thermal spraying of another metal such as copper on the outer surface is required. The applied cam plate made of an iron-based metal has been employed in the conventional configuration. Here, when the cam plate is formed of an aluminum-based metal to reduce the manufacturing cost, it is necessary to increase the thickness of the cam plate in order to secure a predetermined strength. As described above, when the plate thickness of the cam plate increases, the plate thickness of each shoe decreases because a sphere is formed by a pair of shoes with the cam plate interposed therebetween. As a result, there is a possibility that the outer peripheral edge of each shoe becomes more acute-angled, and it becomes easy to be caught in the gap between the cam plate and the piston.

The present invention has been made by paying attention to such problems existing in the prior art. Its main purpose is to reduce the possibility that the outer peripheral edge of the shoe is caught in the gap between the cam plate and the piston when the piston is reciprocated via the cam plate by the rotation of the drive shaft, and the inexpensive variable capacity can be reduced. An object of the present invention is to provide a compressor.

It is a further object of the present invention that the oil staying in the crank chamber can be effectively drawn into the sliding contact portion between the shoe and the piston, and the lubrication of the sliding contact portion is sufficiently ensured. It is an object of the present invention to provide a variable displacement compressor capable of performing the above-mentioned operations.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a crank chamber is formed inside a housing, a drive shaft is rotatably supported, and a part of the housing is formed. A cylinder bore is formed in a cylinder block that constitutes a cylinder bore, and a piston is housed in the cylinder bore so as to be able to reciprocate. In a crank chamber, a cam plate is supported on a drive shaft so as to be integrally rotatable and swingable. Moored around the cam plate via a substantially hemispherical shoe, the piston is reciprocated via the cam plate by the rotation of the drive shaft, and the compression operation of the refrigerant gas is performed at a discharge capacity according to the inclination angle of the cam plate. In the variable displacement compressor described above, a cutout portion is formed on the outer peripheral edge of each shoe.

According to a second aspect of the present invention, in the variable displacement compressor according to the first aspect, the cutout portion of the shoe includes:
At least when the cam plate is shifted to the maximum tilt state, the outer peripheral edge of the shoe is formed inside the spherical receiving seat of the piston.

According to a third aspect of the present invention, in the variable displacement compressor according to the first or second aspect, each of the shoes has a spherical portion slidingly contacting a spherical receiving seat of a piston and an outer surface of a cam plate. It is provided with a flat portion slidably in contact with the side surface, and a cylindrical portion as a cutout formed along the boundary between the spherical portion and the flat portion.

According to the fourth aspect of the invention, the first to third aspects are provided.
In the variable displacement compressor according to any one of the above, the cam plate is formed of an aluminum-based metal. In the variable displacement compressor according to the first aspect, a cutout portion is formed on the outer peripheral edge of each shoe, and the angle of the outer peripheral edge is larger than that of the shoe of the variable displacement compressor having the conventional configuration. For this reason, when the piston is reciprocated via the cam plate by the rotation of the drive shaft, the possibility that the outer peripheral edge of the shoe is caught in the gap between the cam plate and the piston is reduced.

[0013] Further, the cut portion forms a wedge-shaped space between the spherical receiving seat of the piston and the outer peripheral edge of the shoe. Through this space, oil staying in the crank chamber is effectively drawn into the sliding portion between the shoe and the piston. For this reason, lubrication of the sliding contact portion can be easily ensured.

[0014] In the variable displacement compressor according to the second aspect of the present invention, the shoe is so arranged that the outer peripheral edge of the shoe is located inside the spherical receiving seat of the piston at least when the cam plate is shifted to the maximum inclination state. A cut portion is formed on the outer peripheral edge of. For this reason, the outer peripheral edge of the shoe is less likely to be caught in the gap between the cam plate and the piston even when a large compression load is applied, particularly during the compression operation with the maximum discharge capacity.

In the variable displacement compressor according to the third aspect, along the boundary between the spherical portion and the flat portion of each shoe,
A cylindrical portion is formed as a cutout. Therefore, by cutting off the peripheral edge of the boundary between the spherical portion and the flat portion of the shoe to form a cylindrical portion having a predetermined width, the cut portion can be easily processed and formed.

In the variable displacement compressor according to the fourth aspect, since the cam plate is formed of an aluminum-based metal, the manufacturing cost of the cam plate can be reduced. Also, with this configuration, even if the plate thickness of the cam plate is set to be large and the plate thickness of each shoe is reduced, the outer peripheral edge of each shoe is prevented from biting into the gap between the cam plate and the piston. It can be suppressed reliably.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, a front housing 1 forming a part of a housing
1 is joined and fixed to the front of a cylinder block 12, which also forms part of the housing. A rear housing 13, which also forms a part of the housing, is fixedly connected to a rear portion of the cylinder block 12 via a valve plate 14.

In the rear housing 13, the suction chamber 1 is provided.
3a and the discharge chamber 13b are defined. The valve plate 14 is provided with a suction valve 14a and a discharge valve 14b. The closed space formed by the front housing 11 and the cylinder block 12 is a crank chamber 1
5 is made. The front housing 11 and the cylinder block 12 extend through the crank chamber 15.
The drive shaft 16 has a pair of radial bearings 1.
7, and is rotatably supported by a bridge.

The rotary support 18 is provided with the drive shaft 16.
It is fixed to. Also, a swash plate 1 as a cam plate
Numeral 9 is supported by the drive shaft 16 in the crank chamber 15 so as to be slidable and tiltable in the axial direction thereof, and is integrally formed of an aluminum-based metal. The swash plate 19 is connected to the rotating support 18 via a hinge mechanism 20. The swash plate 19 is guided by its hinge mechanism 20 in sliding movement and tilting in the axial direction, and is rotated integrally with the drive shaft 16.

The maximum inclination angle of the swash plate 19 is determined by the stopper 19a provided on the swash plate 19 and the rotation support member 18.
Stipulated by the abutment. The minimum inclination angle of the swash plate 19 is determined by the circlip 16 attached to the drive shaft 16.
b and the swash plate 19 are in contact with each other.

A plurality of cylinder bores 12a are formed in the cylinder block 12. Single-headed piston 2
1 is a cylinder bore 12 in the head portion 21a.
a is reciprocally accommodated in the a. A pair of spherical receiving seats 21c are provided inside the neck 21b of the piston 21.
Are formed facing each other. A pair of substantially hemispherical shoes 22 are interposed between the receiving seat 21 c and both outer peripheral surfaces of the swash plate 19, and the neck 21 b of the piston 21 is moored on the outer periphery of the swash plate 19. The compression reaction force accompanying the compression operation of the piston 21 is received by the front housing 11 via the shoe 22, the swash plate 19, the hinge mechanism 20, the rotary support 18, and the thrust bearing 23.

The air supply passage 24 is formed to connect the discharge chamber 13b and the crank chamber 15. The capacity control valve 25 is provided in the middle of the air supply passage 24. The displacement control valve 25 includes a control valve element 26 and its control valve element 2.
And a diaphragm 28 for adjusting the degree of opening of the control valve hole 27 with respect to the control valve hole 27. Then, the opening degree of the control valve hole 27 by the control valve body 26 is adjusted according to the suction pressure Ps in the suction chamber 13a acting on the diaphragm 28 via the pressure sensing passage 29.

By adjusting the opening of the displacement control valve 25, the supply amount of the high-pressure compressed refrigerant gas supplied from the discharge chamber 13b to the crank chamber 15 through the air supply passage 24 is changed.
The crank chamber 15 acting before and after the piston 21
The pressure difference between the internal pressure Pc and the pressure in the cylinder bore 12a is adjusted. Thereby, the inclination angle of the swash plate 19 is changed, the stroke of the piston 21 is changed, and the discharge capacity is adjusted.

The bleed passage 30 is formed to connect the crank chamber 15 and the suction chamber 13a. The bleed passage 30 is formed in the axial passage 16 a formed in the center of the drive shaft 16, the inside of the accommodation recess 12 b formed in the center of the rear end side of the cylinder block 12, and the rear end surface of the cylinder block 12. It comprises a pressure release groove 12c and a pressure release hole 14c formed in the valve plate 14. The axial passage 16a has a front end having a front radial bearing 17a.
Is open to the crank chamber 15 in the vicinity of. Through the bleed passage 30, a predetermined amount of refrigerant gas is constantly discharged from the crank chamber 15 to the suction chamber 13a.

The thrust bearing 31 and the shaft support spring 32 are accommodated in the recess 12 of the cylinder block 12.
In FIG. 3B, it is interposed between the rear end of the drive shaft 16 and the valve plate 14.

Next, the configuration of the shoe 22 will be described in detail. As shown in FIGS. 2 and 3, each shoe 22 includes a spherical portion 22 a slidable on the spherical receiving seat 21 c of the piston 21 and a flat portion 22 b slidable on both outer circumferential surfaces of the swash plate 19. ing. Spherical part 22 of each shoe 22
A cylindrical portion 22c as a cut portion is formed over the entire outer periphery of the boundary between the a and the flat portion 22b. Further, a tapered surface 22d is formed on the outer periphery of the flat portion 22b of each shoe 22.
Are formed over the entire circumference.

The cylindrical portion 22c is mounted on the shoe 22 at least when the swash plate 19 is shifted to the maximum inclination state.
Is formed by cutting off the outer peripheral edge of the shoe 22 so that the outer peripheral edge is located inside the spherical receiving seat 21c of the piston 21.

Then, as shown in FIG.
With 2c, a first wedge-shaped space C1 is formed between the spherical receiving seat 21c of the piston 21 and the outer peripheral edge of the shoe 22. In addition, by the tapered surface 22d,
A second wedge-shaped space C2 is formed between the outer surface of the swash plate 19 and the flat portion 21b of the shoe 21.

Next, the operation of the variable capacity compressor configured as described above will be described. In this compressor, when the drive shaft 16 is rotated by an external drive source such as a vehicle engine, the swash plate 19 is integrally rotated via the rotation support 18 and the hinge mechanism 20. The rotational movement of the swash plate 19 is converted into a reciprocating linear movement of the piston 21 via the shoe 22, and the head 21a of the piston 21 is reciprocated in the cylinder bore 12a. The reciprocating operation of the piston 21 from the top dead center position to the bottom dead center position causes the refrigerant gas to flow into the suction chamber 1.
The suction valve 14a is pushed away from the cylinder bore 12a.
Inhaled into. The cylinder 21a is moved forward from the bottom dead center position of the piston 21 to the top dead center position.
After the refrigerant gas inside is compressed until it reaches a predetermined pressure, the refrigerant gas is discharged to the discharge chamber 13b by pushing the discharge valve 14b.

Next, the displacement control operation of the variable displacement compressor will be described. In the state where the cooling load is large, the high suction pressure Ps in the suction chamber 13a acts on the diaphragm 28 of the capacity control valve 25, and the control valve body 26 closes the control valve hole 27. Therefore, the air supply passage 24 is shut off, and the supply of the high-pressure compressed refrigerant gas from the discharge chamber 13b to the crank chamber 15 is stopped. In this state, the refrigerant gas in the crank chamber 15 is exclusively extracted through the bleed passage 30 into the suction chamber 13a. For this reason, the crank chamber 15
The difference between the pressure Pc and the pressure in the cylinder bore 12a via the piston 21 is small, and the swash plate 19 is arranged at the maximum inclination state shown by the solid line in FIG. Then, the stroke of the piston 21 is increased, and the compressor is operated at the maximum displacement.

On the other hand, when the cooling load is low, the suction chamber 1
The low suction pressure Ps in 3a acts on the diaphragm 28 of the displacement control valve 25, and the diaphragm 28 is displaced according to the suction pressure Ps. With the displacement of the diaphragm 28, the control valve body 26 opens the control valve hole 27,
High-pressure compressed refrigerant gas is supplied from the discharge chamber 13 b to the crank chamber 15 through the air supply passage 24 in accordance with the opening degree of the control valve hole 27. As a result, the pressure P in the crank chamber 15
c rises, and the difference between the pressure Pc in the crank chamber 15 and the pressure in the cylinder bore 12a through each piston 21 increases. In accordance with this difference, the swash plate 19 is moved to the minimum tilt angle side shown by the chain line in FIG. 1, the stroke of the piston 21 is reduced, and the discharge capacity is reduced.

As described above, in this variable displacement compressor, the pressure Pc of the crank chamber 15 rises and falls by adjusting the opening of the displacement control valve 25 in accordance with the cooling load, that is, the fluctuation of the suction pressure Ps. Is changed.

In the variable displacement compressor of this embodiment, a cylindrical portion 22c is formed on the outer peripheral edge of each shoe 22 as a cut portion. When the swash plate 19 is at least shifted to the maximum tilt state as shown in FIGS.
2 is located inside the spherical receiving seat 21c of the piston 21. For this reason, when the piston 21 is reciprocated via the swash plate 19 by the rotation of the drive shaft 16, the outer peripheral edge of the shoe 22 is suppressed from being caught in the gap S <b> 1 between the swash plate 19 and the piston 21. .

The piston 21 is formed by the cylindrical portion 22c.
A first wedge-shaped space C1 is formed between the spherical receiving seat 21c and the outer peripheral edge of the shoe 22. Therefore, the oil staying in the crank chamber 15 is easily drawn into the sliding contact portion between the spherical portion 22a of the shoe 22 and the spherical receiving seat 21c of the piston 21 via the first wedge-shaped space C1. Become. Furthermore, a tapered surface 22d on the outer periphery of the flat portion 22b
As a result, the outer surface of the swash plate 19 and the flat portion 22b of the shoe 22
A second wedge-shaped space C2 is formed between the two. For this reason, the oil is easily drawn into the sliding contact portion between the flat portion 22b of the shoe 22 and the outer surface of the swash plate 19 via the second wedge-shaped space C2.

The effects that can be expected from the above embodiment will be described below. In the variable displacement compressor of this embodiment, a cylindrical portion 22c is formed on the outer peripheral edge of each shoe 22. For this reason, when the piston 21 is reciprocated through the swash plate 19 by the rotation of the drive shaft 16, the possibility that the outer peripheral edge of the shoe 22 is caught in the gap S <b> 1 between the swash plate 19 and the piston 21 is reduced. Can be.

In the variable displacement compressor of this embodiment, the first wedge-shaped space is provided between the spherical receiving seat 21 c of the piston 21 and the outer peripheral edge of the shoe 22 by the cylindrical portion 22 c on the outer peripheral edge of each shoe 22. C1 is formed. For this reason,
Through this first wedge-shaped space C1, the oil staying in the crank chamber is effectively drawn into the sliding contact portion between the shoe 22 and the piston 21 to ensure sufficient lubrication of the sliding contact portion. Can be.

In the variable displacement compressor of this embodiment, the outer peripheral edge of the shoe 22 is located inside the spherical receiving seat 21 c of the piston 21 at least when the swash plate 19 is shifted to the maximum tilt state. In addition, a cutout portion 22c is formed on the outer peripheral edge of the shoe 22. Therefore, even during a compression operation with the maximum discharge capacity, even when a large compression load is applied, the outer peripheral edge of the shoe 22 is
1 can be reliably reduced.

In the variable displacement compressor of this embodiment, a cylindrical portion 22c is formed along the periphery of the boundary between the spherical portion 22a and the flat portion 22b of each shoe 22. Therefore, by cutting off the peripheral edge of the boundary between the spherical portion 22a and the flat portion 22b of the shoe 22 to form the cylindrical portion 22c having a predetermined width, the cut portion can be easily processed and formed.

In the variable displacement compressor of this embodiment, the swash plate 19 is formed of an aluminum-based metal. For this reason, the swash plate 19 is formed of an iron-based metal, and compared with a conventional configuration in which another metal such as copper is thermally sprayed on the outer surface thereof.
The manufacturing cost of the swash plate 19 can be reduced. Also,
In order to secure a predetermined strength in this configuration, even if the plate thickness of the swash plate 19 is set large and the plate thickness of each shoe 22 is reduced, the outer peripheral edge of the shoe 22 is 21 can be reliably suppressed from being caught in the gap S1.

In the variable displacement compressor of this embodiment, the tapered surface 2
2d is formed, and a second wedge-shaped space C2 is formed between the outer surface of the swash plate 19 and the flat portion 22b of the shoe 22 by the tapered surface 22d. Therefore, the oil staying in the crank chamber 15 is effectively drawn into the sliding contact portion between the shoe 22 and the swash plate 19 via the second wedge-shaped space C2, and lubricating the sliding contact portion. It can be sufficiently secured. In addition, since the swash plate 19 is more efficiently cooled, the swash plate 19 is particularly effective when the swash plate 19 is formed of an aluminum-based metal having a large tendency to decrease in heat resistance at high temperatures.

This embodiment can be embodied with the following modifications. -Omit the tapered surface 22d on each shoe 22. -The swash plate 19 is formed of an iron-based metal.

Even with such a configuration, substantially the same effects as in this embodiment can be expected. Next, a technical idea grasped from this embodiment will be described. The variable displacement compressor according to claim 4, wherein a tapered surface is formed on an outer periphery of a flat portion of the shoe.

With this configuration, the tapered surface allows the outer surface of the cam plate and the flat portion of the shoe to move between the outer surface of the cam plate and the flat portion of the shoe.
A wedge-shaped space is formed. Therefore, the oil staying in the crank chamber is effectively drawn into the sliding portion between the shoe and the cam plate via the wedge-shaped space. Therefore, the present invention is particularly effective when the cam plate is formed of an aluminum-based metal which is more efficiently cooled and whose heat resistance at high temperatures tends to decrease.

[0044]

The present invention is configured as described above, and has the following effects. According to the first aspect of the present invention, when the piston is reciprocated via the cam plate by the rotation of the drive shaft, the possibility that the outer peripheral edge of the shoe is caught in the gap between the cam plate and the piston is reduced. be able to. Also, the oil can be effectively drawn into the sliding portion between the shoe and the piston,
Lubrication of the sliding contact portion can be ensured.

According to the second aspect of the present invention, the outer peripheral edge of the shoe is caught in the gap between the cam plate and the piston even when a large compression load is applied, particularly during the compression operation with the maximum discharge capacity. Can be reliably suppressed.

According to the third aspect of the present invention, by cutting off the peripheral edge between the spherical portion and the flat portion of the shoe to form a cylindrical portion having a predetermined width, the cut portion can be easily processed and formed. Can be.

According to the fourth aspect of the present invention, the cam plate is formed of an aluminum-based metal, so that the manufacturing cost can be reduced. Further, in this configuration, even if the thickness of the cam plate is set to be large and the thickness of each shoe is reduced, the outer peripheral edge of each shoe is prevented from being caught in the gap between the cam plate and the piston. It can be suppressed reliably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a variable displacement compressor according to the present invention.

FIG. 2 is a partially broken front view showing, in an enlarged manner, a mooring structure between a piston and a swash plate.

FIG. 3 is an essential part cross-sectional view showing a part of FIG. 2 in a further enlarged manner;

[Explanation of symbols]

Reference numeral 11: a front housing constituting a part of the housing; 12, a cylinder block constituting a part of the housing; 12a, a cylinder bore; 13, a rear housing constituting a part of the housing; 15, a crank chamber; 16, a drive shaft; 19 ... swash plate as cam plate, 21 ...
Piston, 21c: spherical receiving seat, 22: shoe, 22
a: spherical portion, 22b: flat portion, 22c: cylindrical portion as a cutout portion.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Maka Hori 2-1-1, Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation

Claims (4)

[Claims] 1. A crank chamber is formed inside a housing and a drive shaft is rotatably supported. A cylinder block forming a part of the housing is formed with a cylinder bore, and a piston is reciprocally movable in the cylinder bore. In the crank chamber, a cam plate is supported on the drive shaft so as to be integrally rotatable and swingable in the crank chamber, and the piston is anchored to the outer periphery of the cam plate via a pair of substantially hemispherical shoes. In a variable displacement compressor in which a piston is reciprocated through a cam plate to perform a compression operation of a refrigerant gas with a discharge capacity corresponding to a tilt angle of the cam plate, a cutout portion is formed on an outer peripheral edge of each shoe. Variable capacity compressor. 2. The method according to claim 1, wherein the cutout portion of the shoe is formed such that the outer peripheral edge of the shoe is located inside the spherical receiving seat of the piston at least when the cam plate is shifted to the maximum inclination state. A variable capacity compressor as described. 3. The shoe according to claim 1, wherein each of the shoes is formed along a spherical portion sliding on a spherical receiving seat of the piston, a flat portion sliding on an outer surface of the cam plate, and a boundary between the spherical portion and the flat portion. The variable displacement compressor according to claim 1, further comprising a cylindrical portion serving as a cut-out portion formed. 4. The variable displacement compressor according to claim 1, wherein said cam plate is formed of an aluminum-based metal.