JPH0510254A - Variable capacity type swash plate compressor - Google Patents

Abstract

PURPOSE:To effectively prevent the eccentric abrasion of a piston and a cylinder bore by reducing the side force which a piston is applied, by projectingly installing an annular rail on a swash plate and setting the annular rail and an arcuate groove in eccentricity to a driving shaft side for the center point at an inner bulging-out part. CONSTITUTION:The inner bulging-out parts 17a of the inner shoes 17 and 17 slide in the radial direction, together with the inner bulging-out supporting parts of the outer shoes 18 and 18, and the outer bulging-out parts of the outer shoes 18 and 18 are relatively shifted in the radial direction, together with the cylindrical supporting surface of a piston 19. Accordingly, when a swash plate 15 tilts in a tilt angle theta, the compression load F with which each piston 19 acts on the swash plate 15 through each inner shoe 17, 17 and outer shoe 18 acts on the swash plate 15, as the nearly vertical force from each piston 19 in the vicinity of the top and bottom dead centers, and the side force is reduced. Accordingly, even in case of a one-sided head piston 19, the generation of the one-side contact in a cylinder bore 1a of the piston 19 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable capacity swash plate compressor used in a vehicle air conditioner or the like.

[0002]

2. Description of the Related Art A conventional variable capacity swash plate compressor (hereinafter referred to as
Simply called a compressor. ), JP-A-60-17578
The one disclosed in Japanese Patent Publication No. 3 is known. In this compressor, as shown in FIG. 3, a cylinder block 82 having a plurality of cylinder bores 81 is arranged in the center of a center housing 80, and a front end of the cylinder block 82 forms a sealed crank chamber 83 to form a front portion. The rear housing 8 is closed by a housing 84, and its rear end is interposed by a valve plate 85.
It is blocked by 6. The rear housing 86 is provided with an intake chamber 87 and a discharge chamber 88 that communicate with the cylinder bore 81. A drive shaft 89 is inserted into and supported by a central shaft hole of the cylinder block 82, and a rotary support 90 is supported in the crank chamber 83 by the drive shaft 89 so as to be synchronously rotatable. A swash plate 93 is connected to the rotary support 90 via a hinge mechanism 91. Hinge mechanism 9
Reference numeral 1 includes a long hole 91a penetrating the rotary support 90, and a hinge pin 93b fixed to a swing plate 93a extending from the swash plate 93 and engaged with the long hole 91a.
As shown in FIG. 4, the swash plate 93 has flat surfaces 93a, 9
As shown in FIG. 3, a sleeve 92 is provided between the drive shaft 89 and the drive shaft 89. The sleeve 92 is the drive shaft 8
9 is slidable in the axial direction and maintains spherical contact with the swash plate 93 on the outer peripheral surface. In this way, the swash plate 93 can rotate synchronously with the drive shaft 89 and can be displaced by an inclination angle. In addition, the swash plate 93 has each cylinder bore 81
The piston 94 fitted inside has a pair of shoes 95, 95.
Is moored through. As shown in FIG. 4, each shoe 95 has a flat surface 95 a that abuts with each flat surface 93 a of the swash plate 93.
And a hemispherical portion 95b bulges behind the flat surface 95a. As shown in FIG. 3, the hemispherical portion 95 b of each shoe 95 has a hemispherical bearing surface 94 that is recessed in the neck portion of the piston 94.
a, 94a. The cylinder block 82 is provided with a communication hole 96 that connects the crank chamber 83 and the suction chamber 87, and the communication hole 96 is opened and closed by a control valve 97 that controls the pressure of the crank chamber 83.

In this compressor, when the swash plate 93 rotates as the drive shaft 89 is driven, the hemispherical bearing surface 9 of the piston 94 is rotated.
As shown in FIG. 4, each shoe 95 having a hemispherical portion 95b engaged with the flat surface 4a is flat against the flat surface 93a of the swash plate 93.
5a slides on an elliptical orbit corresponding to the inclination angle of the swash plate 93.
This sliding of the elliptical orbit causes relative displacement in the circumferential direction (arrow A).
And the relative displacement of the swash plate 93 in the radial direction (arrow C). At this time, each shoe 95 has a hemispherical portion 9
5b and the hemispherical bearing surface 94a are swung in the radial direction (arrow B). In this way, only the swinging motion according to the tilt angle of the swash plate 93 is converted into the reciprocating motion of each piston 94 in the cylinder bore 81. As a result, as shown in FIG. 3, the refrigerant gas is sucked from the suction chamber 87 into the cylinder bore 81, and the refrigerant gas is compressed and then discharged to the discharge chamber 88.

The compression capacity of the refrigerant gas discharged into the discharge chamber 88 is controlled by adjusting the pressure in the crank chamber 83 by the control valve 97. That is, when the control valve 97 opens the communication hole 96 to communicate the pressure in the crank chamber 83 with the suction chamber 87, the back pressure acting on the piston 94 is reduced, and the inclination angle of the swash plate 93 is increased. ..
In other words, the hinge pin 93b of the hinge mechanism 91 is attached to the long hole 91.
Within a, the sleeve 92 moves to a position far from the drive shaft 89, the sleeve 92 advances, and the swash plate 93 swings rearward on the outer peripheral surface of the sleeve 92. At this time, each shoe 95 changes the elliptical orbit to a direction in which its major axis is extended due to the expansion of the relative displacement (arrow C). As a result, the stroke of the piston 94 is extended and the compression capacity is increased.

Conversely, if the pressure in the crank chamber 83 is increased by blow-by gas due to the control valve 97 closing the communication hole 96, the back pressure acting on the piston 94 is increased and the inclination angle of the swash plate 93 is increased. Get smaller. In other words, the hinge pin 93b of the hinge mechanism 91 moves the drive shaft 8 inside the long hole 91a.
9, the sleeve 92 moves forward, and the swash plate 93 swings forward on the outer peripheral surface of the sleeve 92. At this time, each shoe 95 changes the elliptical orbit in the direction of shortening its major axis by reducing the relative displacement (arrow C). As a result, the stroke of the piston 94 is shortened and the compression capacity is reduced.

[0006]

However, in each shoe 95 of the compressor, the hemispherical portion 95b and the hemispherical bearing surface 94a are engaged with each other in the radial direction of the swash plate 93 between each shoe 95 of the compressor. Although the displacement is regulated, the radial displacement is allowed between the inclined swash plate 93 and the plane 95a only contacting the plane 93a. Therefore, the compressive load that each piston 94 acts on the swash plate 93 via each shoe 95 acts as a radial force (side force) according to the inclination angle of the swash plate 93 in addition to the axial force. .. In this case, in the same type compressor, the piston 9
Since 4 is a single-headed type, and both heads are not guided into the cylinder bore 81, the piston 94 causes one-sided contact in the cylinder bore 81 due to the side force, which causes uneven wear between the piston 94 and the cylinder bore 81. Becomes

Therefore, the present applicant previously proposed a compressor of the same type which can reduce the side force received by the piston and effectively prevent uneven wear of the piston (Japanese Patent Application No. 2-128).
823). This compressor is, for example, as shown in FIG.
An annular rail 71a is projectingly provided on a swash plate 71 swingably engaged with the drive shaft 70, and the shoes include a pair of inner shoes 72, 72 engaging with the swash plate 71, and each inner shoe 72, 7
2 and a pair of outer shoes 7 that engage with the piston 74
3 and 73. Each inner shoe 72, 72
Is formed with an arcuate groove 72a fitted in the annular rail 71a so as to be relatively displaceable in the circumferential direction, and an inner bulging portion 72b bulging behind the arcuate groove 72a and extending in an arc shape at least in the radial direction of the swash plate 71. It was done. Each outer shoe 73 is
An inner bulging support portion 73a that engages with the inner bulging portion 72b of the inner shoe 72, and an outer bulging portion 7 that bulges rearward from the inner bulging supporting portion 73a and extends in an arc shape at least in the circumferential direction of the swash plate 71.
3b and. A cylindrical bearing surface 74a for guiding the outer bulging portion 73b of the outer shoe 73 in the radial direction of the swash plate 71 is recessed in the neck portion of the piston 74.

However, in the compressor proposed above, as shown in FIG. 6, the annular rail 71a and the arcuate groove 7 are provided.
Since 2a (position Q in the figure) coincides with the center point O of the inner shoes 72, 72, the swash plate 71 and the inner shoes 72, 7
2 may be seized near the root portion P of the annular rail 71a. That is, when the swash plate 71 is inclined at a certain inclination angle θ, a compression load F acts on the inner shoes 72, 72 from the piston 74 at the action point S via the outer shoes 73, 73. This compressive load F is applied to the force F in the tilting direction of the swash plate 71.
t and the force Fn in the direction perpendicular to the annular rail 71a, and if a uniform surface pressure acts on the entire side surface of the annular rail 71a, this surface pressure is applied to the center A of the side surface of the annular rail 71a. The force ft acts as a reaction force of the force Ft in the tilt direction. The force ft due to this surface pressure is the force F
Although the magnitude is equal to t, the action point is different between point S and point A, and therefore a clockwise moment Mt is generated in the figure. The swash plate 71 and the inner shoes 72, 72 are annular rails 71.
Rotation must be blocked by the engagement of a with the arcuate groove 72a, and the moment Mt is generated by the force Fn acting at the point S and the force fn of the same magnitude acting as a reaction force of this force Fn. It should be canceled by the counterclockwise moment Mn in the figure. The point of action B of this force fn is located to the left of the point S in the figure, is close to the root portion P of the annular rail 71a, and coincides with the root portion P depending on the inclination angle of the swash plate 71. Therefore, the component force Fn of the larger compressive load F is applied to the root portion P.
The load is concentrated by a force fn equal to, and in the worst case, the swash plate 71 and the inner shoes 72, 72 may seize near the root portion P.

The present invention solves the problem that, in the same type compressor, the side force received by the piston is reduced, uneven wear of the piston is effectively prevented, and seizure between the swash plate and the inner shoe is effectively prevented. It is a task that should be done.

[0010]

In order to solve the above-mentioned problems, the compressor of the present invention has an annular rail projecting from the swash plate, and the shoes serve as a pair of internal members that engage with the swash plate. A shoe and a pair of outer shoes that engage with each of the inner shoes and the piston are adopted, and each of the inner shoes has an arc-shaped groove that is fitted in the annular rail so as to be relatively displaceable in the circumferential direction, and the arc-shaped groove. At least the inner bulging portion that bulges behind the groove and expands in an arc shape in the radial direction of the swash plate is formed, and the annular rail and the arc-shaped groove are formed on the drive shaft side with respect to the center point of the inner bulging portion. The new means of uneven distribution is adopted.

[0011]

In the compressor of the present invention, when the swash plate rotates with the drive of the drive shaft, each inner shoe is supported by fitting the arcuate groove into the annular rail of the swash plate, and the arcuate groove side of the inner shoe is supported. The surface is relatively displaced only in the circumferential direction. In other words, the arcuate groove of each inner shoe is restricted from being displaced in the radial direction between the inner shoe and the inclined swash plate by the engagement with the annular rail. Also, the inner swelling portion of each inner shoe slides radially with the outer shoe in accordance with the inclination angle of the swash plate, and the outer shoe is displaced relative to the piston. Also, when the swash plate swings back and forth through the sleeve due to capacity control, the inner bulge of the inner shoe slides radially with the outer shoe, while the outer shoe moves radially with the piston. Is displaced.

Therefore, the compressive load that each piston acts on the swash plate via the inner shoe and the outer shoe acts on the swash plate as a force almost vertical from each piston near the top and bottom dead centers, and the side force is applied. To reduce. Therefore, even if the piston is a single-headed piston, the piston is less likely to make one-sided contact in the cylinder bore. Further, at this time, in this compressor, since the annular rail of the swash plate and the arcuate groove of the inner shoe are unevenly distributed toward the drive shaft side with respect to the center point of the inner bulging portion of the inner shoe, The point of action of the reaction force of the force in the direction perpendicular to the swash plate due to the compressive load is farther from the root of the annular rail than that proposed previously. Therefore, the load is dispersed in the vicinity of the root portion, and seizure between the swash plate and the inner shoe, which occurs in the vicinity of the root portion, is prevented.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. This compressor, as shown in FIG.
A cylinder block 1 having a plurality of cylinder bores 1a is arranged in a central portion, a front end thereof forms a closed crank chamber 2a and is closed by a front housing 2, and a rear end of the cylinder block 1a via a valve plate 12 is rear. It is closed by the housing 3. The rear housing 3 is provided with a suction chamber 3a and a discharge chamber 3b which communicate with the cylinder bore 1a. A drive shaft 4 is inserted into and supported by a central shaft hole of the cylinder block 1, and a rotary support 5 is rotatably supported in the crank chamber 2a by the drive shaft 4. A rotary drive 11 is supported on the rotary support 5 via a hinge mechanism K. In the hinge mechanism K, a mounting hole 6a is formed through a support arm 6 projecting rearward from the rotary support 5, a race 8 is fixed to the mounting hole 6a, and a ball 9 that engages with the race 8 is provided. Equipped so that it can swing. A guide hole 9a is formed through the spherical body 9, and a guide pin 10 is supported in the guide hole 9a so as to be capable of reciprocating. A mounting hole 11a is also formed through the rotary drive body 11, and the guide pin 10 is press-fitted into the mounting hole 11a.

A swash plate 15 is fixed to the rear of the rotary drive body 11 by a tightening ring 16. As shown in FIG. 2, the swash plate 15 is provided with annular rails 15c, 15c projecting on the front and back sides with the symmetrical axis of the drive shaft 4 as the center.
A pair of substantially semi-cylindrical inner shoes 17, 17 are engaged with each annular rail 15c so as to be relatively displaceable only in the circumferential direction. Each of the inner shoes 17, 17 has a semi-cylindrical portion 17b as an arcuate groove 17a fitted into each annular rail 15c and an inner bulge that radially expands in the radial direction of the swash plate 15 bulging behind the arcuate groove 17a. And are formed. With this compressor,
The annular rail 15c and the arcuate grooves 17a, 17a (position Q in the figure) are the semi-cylindrical portions 17b, 1 of the inner shoes 17, 17.
It is most characterized in that it is unevenly distributed to the drive shaft 4 side with respect to the center point O of 7b. Thus, the swash plate 15 and the inner shoe 17,
The displacement of 17 is restricted in the radial direction. The upper surfaces of the annular rails 15c and 15c and the bottom surface of the arc-shaped groove 17a are tapered surfaces that are inclined in the axial direction of the drive shaft 4 to prevent the inner shoes 17 and 17 from becoming thin and maintain strength. ing. Further, as shown in FIG. 1, the semi-cylindrical portions 17b of the inner shoes 17, 17 are engaged with outer shoes 18, 18 having a substantially semi-cylindrical shape. Each outer shoe 18, 18
Is a semi-cylindrical inner bulging bearing portion that engages with the semi-cylindrical portion 17b of the inner shoes 17, 17 and a swash plate 15 bulging backward from the inner bulging bearing portion in a substantially circumferential direction. The outer swelling portion spreads in an arc shape. Further, a cylindrical bearing surface for guiding the outer bulging portions of the outer shoes 18, 18 in the radial direction of the swash plate 15 is recessed in the swash plate passage groove of the neck portion of the piston 19. These inner shoes 17, 17, outer shoes 18, 18
The piston 19 is the inner swelling portion 1 of the inner shoe 17, 17.
The center of the inner bulging support portion of 7b and the outer shoes 18, 18 is located at the center of the swash plate 15. Thus, the inner shoes 17, 17 and the outer shoes 18,
A plurality of pistons 19 moored via 18 are housed in each cylinder bore 1a so as to be capable of reciprocating.

A sleeve 13 is interposed between the rotary driver 11 and the drive shaft 4. The sleeve 13 is provided so as to be slidable in the axial direction of the drive shaft 4 via springs 20 and 21, and a sleeve pin (not shown) is projectingly provided on the outer surface in the direction perpendicular to the axis. This sleeve pin is engaged with a mounting hole (not shown) of the rotary drive body 11. In this way, the swash plate 15 can be rotated synchronously with the drive shaft 4 via the rotary support 5 and the rotary drive 11, and can be displaced by a tilt angle via the hinge mechanism K and the sleeve 13.

Further, the rear housing 3 is equipped with control valves 21, 21 for adjusting the pressure in the crank chamber 2a. In this compressor, as the drive shaft 4 is driven, the swash plate 1
When 5 rotates, each piston 19 and outer shoes 18, 18
The inner shoes 17, 17 engaged with each other slide in the circumferential direction on the annular rails 15c, 15c with respect to the swash plate 15, and each piston 19 reciprocates in the cylinder bore 1a. Refrigerant gas is sucked into the cylinder bore 1a, compressed, and then discharged into the discharge chamber 3b.

At this time, in this compressor, as shown in FIG. 2, the inner shoes 17, 17 are supported by fitting the arc-shaped grooves 17a, 17a into the annular rail 15c of the swash plate 15, and the arc-shaped grooves 17a, 17a. The surface on the groove 17a side is relatively displaced only in the circumferential direction. That is, the arcuate grooves 17a, 17a of the inner shoes 17, 17 are restricted from being displaced in the radial direction between the inner shoes 17, 17 by engaging the annular rail 15c with the inclined swash plate 15. In addition, each inner shoe 17, 17 is a swash plate 15.
Depending on the inclination angle of the
18 slides in the radial direction with the inner bulging support portion of the outer shoe 18,
The outer bulging portion of 18 is displaced relative to the cylindrical bearing surface of the piston 19.

As shown in FIG. 1, the compression capacity of the refrigerant gas discharged into the discharge chamber 3b is controlled by adjusting the pressure in the crank chamber 2a by the control valves 21, 21. That is, for example, if the control valves 21, 21 connect the crank chamber 2a and the suction chamber 3a to each other, the back pressure acting on the piston 19 is lowered, and the inclination angle of the swash plate 15 is increased. That is, the ball 9 slides on the race 8 to swing the guide pin 10 forward, and the rotary drive body 11 swings rightward about the sleeve pin and the sleeve 13 moves.
Moves forward against the spring 21, and the guide pin 10 moves into the guide hole 9
It slides in the direction of entering a. Then, the swash plate 15 swings rearward through the rotary drive body 11 and the sleeve 13, and the tilt angle becomes large. Therefore, the stroke of the piston 19 is extended and the compression capacity is increased.

On the contrary, the control valves 21, 21 are arranged in the crank chamber 2a.
When the communication between the suction chamber 3a and the suction chamber 3a is closed, the pressure in the crank chamber 2a is increased by the blow-by gas, and the back pressure acting on the piston 19 is increased, so that the inclination angle of the swash plate 15 is reduced. In other words, the ball 9 slides on the race 8 to swing the guide pin 10 rearward, and the rotation driving member 11
Swings to the left around the sleeve pin, the sleeve 13 moves backward against the spring 20, and the guide pin 10 slides in the direction of coming out of the guide hole 9a. Then, the swash plate 15 swings forward through the rotary drive body 11 and the sleeve 13, and the inclination angle becomes smaller. Therefore, the piston 19
The stroke is reduced and the compression capacity is reduced.

At this time, the inner bulging portion 17a of the inner shoes 17, 17 slides radially with the inner bulging support portion of the outer shoes 18, 18, while the outer bulging portion of the outer shoes 18, 18 is a piston. Radial displacement is made relative to the cylindrical bearing surface of 19. Therefore, when the swash plate 15 is inclined at a certain inclination angle θ, the compression load F acting on the swash plate 15 by each piston 19 via the inner shoes 17, 17 and the outer shoe 18 causes the upper and lower dead. In the vicinity of the point, each piston 19 acts on the swash plate 15 as a substantially vertical force to reduce the side force. For this reason,
Even with the single-headed piston 19, the piston 19 is unlikely to cause one-sided contact in the cylinder bore 1a.

At this time, in this compressor,
If the compressive load F is decomposed into a force Ft in the direction of inclination of the swash plate 15 and a force Fn in the direction perpendicular to the annular rail 15c, if uniform surface pressure acts on the entire side surface of the annular rail 15c, In the same manner as that proposed in the above, the force ft due to this surface pressure is applied to the center A of the side surface of the annular rail 15c in the direction of inclination Ft.
Is acting as a reaction force of. The force ft due to this surface pressure is equal in magnitude to the force Ft, but since the point of action is different between points S and A, a clockwise moment Mt is generated in the figure. Rotation of the swash plate 15 and the inner shoes 17, 17 must be blocked by the engagement of the annular rail 15c and the arcuate groove 17a, and the moment Mt is the force Fn acting at the point S and the reaction of this force Fn. It should be canceled by the counterclockwise moment Mn in the figure generated by the force fn having the same magnitude acting as the force.
The point of action B of this force fn is located to the left of the point S in the figure, but the ring rail 15c is larger than that proposed earlier.
It is far from the root portion P and does not coincide with the root portion P due to the inclination angle θ of the swash plate 70. Therefore, in the root portion P, the load due to the force fn equal to the component force Fn of the larger compressive load F is dispersed by the length BP, and the swash plate 15 and the inner shoes 17, 17 generated near the root portion P are distributed.
Burning with is effectively prevented.

Therefore, in this compressor, the piston 1
It is possible to reduce the side force received by 9 and effectively prevent uneven wear of the piston 19, and at the same time, to prevent swash plate 15
Since it is possible to effectively prevent the seizure between the inner shoes 17 and the inner shoes 17, it is possible to exhibit excellent durability.

[0023]

As described above in detail, in the compressor of the present invention, the swash plate is provided with the annular rail projecting, and the shoes include the pair of inner shoes engaging with the swash plate, the inner shoes and the piston. Each of the inner shoes is formed with an arcuate groove and an inner bulge, and the most characteristic configuration is that the annular rail and the arcuate groove are located at the center point of the inner bulge. On the other hand, because it is unevenly distributed on the drive shaft side,
The side force received by the piston can be reduced, uneven wear of the piston and the cylinder bore can be effectively prevented, and seizure between the swash plate and the inner shoe can be effectively prevented.

Therefore, when this compressor is used in, for example, a vehicle air conditioner, it is possible to exhibit even higher durability than that proposed previously.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a compressor according to an embodiment.

FIG. 2 is a schematic cross-sectional view of a main part of the compressor of the embodiment.

FIG. 3 is a vertical sectional view of a conventional compressor.

FIG. 4 is an exploded perspective view of essential parts of a conventional compressor.

FIG. 5 is an exploded perspective view of a main part of the previously proposed compressor.

FIG. 6 is a schematic cross-sectional view of a main part of the previously proposed compressor.

[Explanation of symbols]

1 ... Cylinder block 2, 3 ... Housing
2a ... Crank chamber 3a ... Suction chamber 3b ... Discharge chamber
1a ... Cylinder bore 19 ... Piston 4 ... Drive shaft
5 ... Rotation support 11 ... Rotation drive K ... Hinge mechanism
13 ... Sleeve 15 ... Swash plate 15c ... Annular rail
17 ... Inner shoe 17a ... Arc-shaped groove 17b ... Inner bulging portion (semi-cylindrical portion) 18 ... Outer shoe Q ... Position of annular rail and arc-shaped groove in the drawing O ... Center point of inner bulging portion (semi-cylindrical portion)

Claims (1)

Claim: What is claimed is: 1. A crank chamber, a suction chamber, a discharge chamber, and a plurality of cylinder bores connected to these are defined and formed in a housing, and a single-head piston is reciprocally movable in each of the cylinder bores. A rotary support located in the crank chamber is rotatably supported on the drive shaft that is accommodated and supported by the housing, and a hinge mechanism is provided between the rotary support and the rotary support and between the rotary support and the drive shaft. A swash plate is pivotally supported via a sleeve so as to be capable of synchronous rotation and tilt angle displacement, and a shoe for converting the swinging motion of the swash plate into reciprocating motion of each piston is interposed between the swash plate and the piston. A variable capacity swash plate compressor configured to change the compression capacity by controlling the tilt angle of the swash plate by the pressure in the crank chamber, wherein the swash plate is provided with an annular rail, Shoe It is composed of a pair of inner shoes that engage with the swash plate and a pair of outer shoes that engage with the inner shoes and the piston, and the inner shoes are fitted in the annular rail so as to be relatively displaceable in the circumferential direction. And an inner bulging portion that bulges behind the arc-shaped groove and expands in an arc shape at least in the radial direction of the swash plate are formed, and the annular rail and the arc-shaped groove are formed in the inner bulged portion. A variable capacity type swash plate compressor characterized by being unevenly distributed toward the drive shaft side with respect to a center point.