VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR

BACKGROUND OF THE INVENTION

The present invention relates to a variable displacement type swash plate compressor.

A compressor of this kind has been disclosed in Japanese Laid-Open Patent Publication No. 52-131204. The compressor of this kind has a swash plate and a mobile body that moves to an axial direction of a rotation shaft for changing an inclination angle of the swash plate. The compressor further has, in the housing, a control pressure chamber into which a control gas is introduced. The mobile body moves to the axial direction of the rotation shaft, when the pressure inside the control pressure chamber is changed following the introduction of the control gas. Following the movement to the axial direction of the rotation shaft, the mobile body transmits force to a center part of the swash plate to change the inclination angle of the swash plate. As a result, the inclination angle of the swash plate is changed.

The above configuration of transmitting force from the mobile body to the center part of the swash plate requires large force for changing the inclination angle of the swash plate. For this purpose, it is considered appropriate to transmit force of changing the inclination angle of the swash plate from the mobile body to the outer peripheral part of the swash plate. According to this configuration, the inclination angle of the swash plate can be changed with smaller force than that for transmitting force from the mobile body to the center part of the swash plate. Therefore, a flow rate of the control gas introduced into the control pressure chamber necessary to change the inclination angle of the swash plate can be minimized.

However, according to the configuration of transmitting force of changing the inclination angle of the swash plate from the mobile body to the outer peripheral part of the swash plate, moment works to incline the mobile body to a moving direction of the mobile body following the change of the inclination angle of the swash plate. When the mobile body is inclined, the mobile body and the rotation shaft are brought into contact with each other at two points on both sides sandwiching the rotation shaft. In this case, force for supporting the inclination of the mobile body is generated at contact points between the mobile body and the rotation shaft and a twist occurs by frictional force generated by this force. A sliding resistance increases by this twist, and the mobile body becomes unable to move smoothly to an axial direction of the rotation shaft. As a result, the inclination angle of the swash plate becomes unable to be smoothly changed.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a variable displacement type swash plate compressor capable of smoothly changing the inclination angle of the swash plate.

In order to solve the above problem, according to a first aspect of the present invention, there is provided a variable displacement type swash plate compressor including: a housing in which there are formed a suction chamber, a discharge chamber, a swash plate chamber communicated with the suction chamber, and cylinder bores; a rotation shaft, which is rotatably supported by the housing; a swash plate, which is rotatable in the swash plate chamber by rotation of the rotation shaft; a link mechanism, which is provided between the rotation shaft and the swash plate and permits change of an inclination angle of the swash plate to a first direction orthogonal to an axial line of the rotation shaft; a piston, which is housed to reciprocate in the cylinder bore; a converting mechanism, which reciprocates, by rotation of the swash plate, the piston in the cylinder bore by stroke according to the inclination angle of the swash plate; an actuator, which is located in the swash plate chamber and changes the inclination angle of the swash plate; and a control mechanism which controls the actuator. The actuator has: a partitioning body which is provided in the rotation shaft; a mobile body, which can move along an axial line of the rotation shaft in the swash plate chamber; a control pressure chamber, which is partitioned by the partitioning body and the mobile body and moves the mobile body by introducing a refrigerant from the discharge chamber; and a coupling member, which is provided, between the mobile body and the swash plate, on an outer side in a radial direction from an insertion hole of the swash plate through which the rotation shaft is passed. The mobile body has a sliding part that slides on the rotation shaft or on the partitioning body following movement along an axial line of the rotation shaft. The swash plate has a guide surface for guiding the coupling member and for changing the inclination angle of the swash plate following movement of the mobile body along an axial line of the rotation shaft. The guide surface is set such that a perpendicular line or a normal line of the guide surface and an axial line of the rotation shaft cross in a region surrounded by the sliding part, as viewed from a direction orthogonal to both the axial line of the rotation shaft and the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view illustrating a variable displacement type swash plate compressor according to the present invention;

FIG. 2 is a schematic view illustrating a relationship between a control pressure chamber, a pressure adjusting chamber, a suction chamber, and a discharge chamber;

FIG. 3 is an enlarged side sectional view illustrating a periphery of a coupling pin;

FIG. 4 is a side sectional view illustrating a compressor when an inclination angle of a swash plate is a minimum inclination angle;

FIG. 5 is an enlarged side sectional view illustrating a periphery of a coupling pin according to another example;

FIG. 6 is an enlarged side sectional view illustrating a periphery of a coupling pin according to still another example;

FIG. 7 is an enlarged side sectional view illustrating a periphery of a coupling pin according to still another example;

FIG. 8 is an enlarged side sectional view illustrating a periphery of a coupling pin according to still another example;

FIG. 9 is an enlarged side sectional view illustrating a periphery of a coupling pin according to still another example; and

FIG. 10 is an enlarged side sectional view illustrating a periphery of a coupling pin according to still another example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a preferred embodiment of a variable displacement type swash plate compressor according to the present invention will be described with reference to FIGS. 1 to 4. In the following description, the variable displacement type swash plate compressor will be simply referred to as a compressor. The compressor is used for a vehicle air conditioner. Further, a left side in FIG. 1 will be defined as a front side, and a right side will be defined as a rear side.

As illustrated in FIG. 1, a housing 11 of a compressor 10 is configured by a first cylinder block 12 and a second cylinder block 13, which are joined to each other, a front housing 14, which is joined to a front end of the first cylinder block 12, and a rear housing 15, which is joined to a rear end of the second cylinder block 13.

A first valve/port forming body 16 is present between the front housing 14 and the first cylinder block 12. A second valve/port forming body 17 is present between the rear housing 15 and the second cylinder block 13.

A suction chamber 14a and a discharge chamber 14b are partitioned between the front housing 14 and the first valve/port forming body 16. The discharge chamber 14b is located on an outer side in the radial direction of the suction chamber 14a. A suction chamber 15a and a discharge chamber 15b are partitioned between the rear housing 15 and the second valve/port forming body 17. A pressure adjusting chamber 15c is formed in the rear housing 15. The pressure adjusting chamber 15c is located at the center of the rear housing 15. The suction chamber 15a is located on an outer side in the radial direction of the pressure adjusting chamber 15c. The discharge chamber 15b is located on an outer side in the radial direction of the suction chamber 15a. The discharge chambers 14b and 15b are connected to each other via a discharge passage not illustrated. The discharge passage is connected to an external refrigerant circuit not illustrated. The discharge chambers 14b and 15b are discharge pressure regions.

In the first valve/port forming body 16, there are formed a suction port 16a, which communicates with the suction chamber 14a, and a discharge port 16b, which communicates with the discharge chamber 14b. In the second valve/port forming body 17, there are formed a suction port 17a, which communicates with the suction chamber 15a, and a discharge port 17b, which communicates with the discharge chamber 15b. In each of the suction ports 16a and 17a, a suction valve mechanism not illustrated is provided. In each of the discharge ports 16b and 17b, a discharge valve mechanism not illustrated is provided.

In the housing 11, a rotation shaft 21 having an axial line L is rotatably supported. The rotation shaft 21 has a front end, which is positioned near a front end of the housing 11, and a rear end, which is positioned near a rear end of the housing 11. A front end of the rotation shaft 21 is passed through a shaft hole 12h, which is formed in the first cylinder block 12. The front end of the rotation shaft 21 is located in the front housing 14. A rear end of the rotation shaft 21 is passed through a shaft hole 13h which is formed in the second cylinder block 13. The rear end of the rotation shaft 21 is located in the pressure adjusting chamber 15c.

The front end of the rotation shaft 21 is rotatably supported by the first cylinder block 12 via the shaft hole 12h, and the rear end of the rotation shaft 21 is rotatably supported by the second cylinder block 13 via the shaft hole 13h. A lip seal type shaft seal device 22 is present between the front housing 14 and the rotation shaft 21. An engine for a vehicle as an external driving source is coupled to the front end of the rotation shaft 21 for operation, via a power transmission mechanism not illustrated. The power transmission mechanism is an all-time transmission type clutchless mechanism configured by combination of a belt and a pulley, for example.

In the housing 11, a swash plate chamber 24, which is partitioned by the first cylinder block 12, and the second cylinder block 13 are formed. In the swash plate chamber 24, a swash plate 23, which rotates by obtaining driving force from the rotation shaft 21 and moves by inclination with respect to the rotation shaft 21, is housed. In the swash plate 23, an insertion hole 23a, through which the rotation shaft 21 is passed, is formed. The swash plate 23 is fitted to the outer peripheral surface of the rotation shaft 21 by passing the rotation shaft 21 through the insertion hole 23a.

In the first cylinder block 12, a plurality of first cylinder bores 12a are formed (only one first cylinder bore 12a is illustrated in FIG. 1). The plurality of first cylinder bores 12a penetrate through the first cylinder block 12 in the axial direction, and are located around the rotation shaft 21. Each first cylinder bore 12a communicates with the suction chamber 14a via the suction port 16a and communicates with the discharge chamber 14b via the discharge port 16b. In the second cylinder block 13, a plurality of second cylinder bores 13a are formed (only one second cylinder bore 13a is illustrated in FIG. 1). The plurality of second cylinder bores 13a penetrate through the second cylinder block 13 in the axial direction and are located around the rotation shaft 21. Each second cylinder bore 13a communicates with the suction chamber 15a via the suction port 17a and communicates with the discharge chamber 15b via the discharge port 17b. The first cylinder bore 12a and the second cylinder bore 13a are located at the front and the back to form a pair. In both the first cylinder bore 12a and the second cylinder bore 13a that form the pair, a double-headed piston 25 is housed to reciprocate in forward and backward directions. The compressor 10 is a double-headed piston type swash plate compressor.

Each double-headed piston 25 is held at an outer peripheral part of the swash plate 23 via a pair of shoes 26. When the swash plate 23 rotates together with the rotation shaft 21, the rotation of the swash plate 23 is converted into reciprocal linear motion of the double-headed piston 25 via the shoes 26. Therefore, the pair of shoes 26 is a conversion mechanism that reciprocates the double-headed piston 25 by the rotation of the swash plate 23 in the first cylinder bore 12a and the second cylinder bore 13a. A space surrounded by the double-headed piston 25 in each first cylinder bore 12a and the first valve/port forming body 16 is a first compression chamber 20a. A space surrounded by the double-headed piston 25 in each second cylinder bore 13a and the second valve/port forming body 17 is a second compression chamber 20b.

In the first cylinder block 12, a first large-diameter hole 12b is formed. The first large-diameter hole 12b is continuous to the shaft hole 12h and has an inner diameter larger than that of the shaft hole 12h. The first large-diameter hole 12b communicates with the swash plate chamber 24. The swash plate chamber 24 and the suction chamber 14a communicate with each other by a suction passage 12c that penetrates through the first cylinder block 12 and the first valve/port forming body 16.

In the second cylinder block 13, a second large-diameter hole 13b is formed. The second large-diameter hole 13b is continuous to the shaft hole 13h and has an inner diameter larger than that of the shaft hole 13h. The second large-diameter hole 13b communicates with the swash plate chamber 24. The swash plate chamber 24 and the suction chamber 15a communicate with each other by a suction passage 13c that penetrates through the second cylinder block 13 and the second valve/port forming body 17.

On the peripheral wall of the second cylinder block 13, a suction opening 13s is formed. The suction opening 13s is connected to the external refrigerant circuit. A refrigerant gas is suctioned into the swash plate chamber 24 from the external refrigerant circuit via the suction opening 13s and is then suctioned into the suction chambers 14a and 15a via the suction passages 12c and 13c. Accordingly, the suction chambers 14a and 15a and the swash plate chamber 24 are suction pressure regions, and their pressures are substantially equal.

From the outer peripheral surface of the rotation shaft 21, a ring-shaped flange part 21f protrudes. The flange part 21f is located in the first large-diameter hole 12b. A first thrust bearing 27a is provided between the flange part 21f of the rotation shaft 21 and the first cylinder block 12. A circular cylindrical supporting member 39 is press-fitted to the rear end of the rotation shaft 21. A ring-shaped flange part 39f protrudes from the outer peripheral surface of the supporting member 39. The flange part 39f is located in the second large-diameter hole 13b. A second thrust bearing 27b is provided between the flange part 39f of the supporting member 39 and the second cylinder block 13.

In the swash plate chamber 24, an actuator 30 capable of changing the inclination angle of the swash plate 23 is housed. The actuator 30 changes the inclination angle of the swash plate 23 to a first direction (a vertical direction in FIG. 1) orthogonal to the axial line L of the rotation shaft 21. The actuator 30 is provided between the flange part 21f of the rotation shaft 21 and the swash plate 23. The actuator 30 has a ring-shaped partitioning body 31 that can rotate integrally with the rotation shaft 21. Further, the actuator 30 has a bottomed circular-cylindrical mobile body 32. The mobile body 32 is located between the flange part 21f and the partitioning body 31. The mobile body 32 is movable to the axial direction of the rotation shaft 21 in the swash plate chamber 24.

The mobile body 32 is formed by a circular ring-shaped bottom part 32a and a circular cylinder part 32b. The bottom part 32a has a through-hole 32e through which the rotation shaft 21 passes. The circular cylinder part 32b extends from an outer peripheral edge of the bottom part 32a to the axial direction of the rotation shaft 21. The inner peripheral surface of the circular cylinder part 32b can move by sliding to an outer peripheral edge of the partitioning body 31. Accordingly, the mobile body 32 is integrally rotatable with the rotation shaft 21 via the partitioning body 31. A portion between the inner peripheral surface of the circular cylinder part 32b and the outer peripheral edge of the partitioning body 31 is sealed by a seal member 33. A portion between the inner peripheral surface of the through-hole 32e and the outer peripheral surface of the rotation shaft 21 is sealed by a seal member 34. The actuator 30 has a control pressure chamber 35, which is partitioned by the partitioning body 31, and the mobile body 32.

In the rotation shaft 21, a first shaft inner passage 21a extending along the axial direction of the rotation shaft 21 is formed. A rear end of the first shaft inner passage 21a is opened to the pressure adjusting chamber 15c. Further, in the rotation shaft 21, a second shaft inner passage 21b extending to a radial direction of the rotation shaft 21 is formed. The second shaft inner passage 21b has one end part, which communicates with a front end of the first shaft inner passage 21a, and the other end part, which is opened to the control pressure chamber 35. Accordingly, the control pressure chamber 35 and the pressure adjusting chamber 15c communicate with each other via the first shaft inner passage 21a and the second shaft inner passage 21b.

As illustrated in FIG. 2, the pressure adjusting chamber 15c and the suction chamber 15a communicate with each other via a bleed passage 36. The bleed passage 36 is provided with an orifice 36a. A flow rate of the refrigerant gas that flows in the bleed passage 36 is squeezed by the orifice 36a. Further, the pressure adjusting chamber 15c and the discharge chamber 15b communicate with each other via a supply passage 37. On the supply passage 37, there is provided an electromagnetic control valve 37s as a control mechanism that controls the actuator 30. The control valve 37s adjusts the opening of the supply passage 37 based on the pressure of the suction chamber 15a. The control valve 37s adjusts a flow rate of the refrigerant gas that flows in the supply passage 37.

From the discharge chamber 15b, the refrigerant gas is introduced into the control pressure chamber 35 via the supply passage 37, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b. Further, from the control pressure chamber 35, the refrigerant gas is discharged to the suction chamber 15a via the second shaft inner passage 21b, the first shaft inner passage 21a, the pressure adjusting chamber 15c, and the bleed passage 36. The pressure inside the control pressure chamber 35 is changed by these items. By the pressure difference between the control pressure chamber 35 and the swash plate chamber 24, the mobile body 32 moves to the partitioning body 31 in the axial direction of the rotation shaft 21. Accordingly, the refrigerant gas that is introduced into the control pressure chamber 35 is the control gas used for movement control of the mobile body 32.

As illustrated in FIG. 1, in the swash plate chamber 24, a lug arm 40 is located between the swash plate 23 and the flange part 39f. The lug arm 40 is a link mechanism that permits change of the inclination angle of the swash plate 23. The lug arm 40 is bent in approximately an L shape from an upper end toward a lower end. A weight part 40w is formed on the upper end of the lug arm 40. The weight part 40w protrudes to the front of the swash plate 23 by passing through a groove part 23b of the swash plate 23.

The upper end of the lug arm 40 is coupled to the upper end of the swash plate 23 by a columnar first pin 41, which is located to cross the inside of the groove part 23b. Accordingly, the upper end of the lug arm 40 is supported on the swash plate 23 to be able to oscillate around a first oscillation center M1 that matches the axis center of the first pin 41. The lower end of the lug arm 40 is coupled to the supporting member 39 by a columnar second pin 42. Accordingly, the lower end of the lug arm 40 is supported on the supporting member 39 to be able to oscillate around a second oscillation center M2 that matches the axis center of the second pin 42.

From a front end of the circular cylinder part 32b of the mobile body 32, a coupling part 32c protrudes toward the swash plate 23. A columnar coupling pin 43 as a coupling member is press-fitted and fixed to the coupling part 32c. Further, a long-hole shaped insertion hole 23h through which the coupling pin 43 can be passed is formed in the swash plate 23. The insertion hole 23h is formed on an outer side in the radial direction from the insertion hole 23a of the swash plate 23 (a lower side in FIG. 1). The coupling part 32c is coupled to a lower end of the swash plate 23 via the coupling pin 43. The coupling pin 43 is held on the swash plate 23 so as to be able to move by sliding in the insertion hole 23h.

As illustrated in FIG. 3, the insertion hole 23h has a guide surface 44 for guiding the coupling pin 43 and for changing the inclination angle of the swash plate 23 following movement of the mobile body 32 to the axial direction of the rotation shaft 21. The guide surface 44 is located near the mobile body 32 in the insertion hole 23h. The guide surface 44 has a flat surface part 44a that is inclined to the moving direction of the mobile body 32 (the axial direction of the rotation shaft 21).

The mobile body 32 has a sliding part 32s that slides on the rotation shaft 21 following the movement of the mobile body 32 to the axial direction of the rotation shaft 21. The sliding part 32s is an inner peripheral surface of the through-hole 32e of the bottom part 32a and extends along the axial direction of the rotation shaft 21.

In this case, following the change of the inclination angle of the swash plate 23, a point at which a perpendicular line L1 of the flat surface part 44a and the axial line L of the rotation shaft 21 cross is set as an intersection P1, viewed from a direction orthogonal to both an axial direction of the rotation shaft 21 and the first direction (a vertical direction), that is, a depth direction on the paper surface in FIG. 3. An inclination angle θ1 of the flat surface part 44a is set such that, when the inclination angle of the swash plate 23 is a maximum inclination angle, the intersection P1 is located in a region Z1 surrounded by the sliding part 32s, viewed from the direction orthogonal to both the axial direction of the rotation shaft 21 and the first direction.

The inclination angle θ1 is the inclination when the inclination angle of the swash plate 23 is a maximum inclination angle and is the inclination of the swash plate 23 with respect to a direction orthogonal to the axial direction of the rotation shaft 21. The region Z1 is a region in which the sliding part 32s extends in the axial direction of the rotation shaft 21 and is indicated by dot hatching in FIG. 3.

In the compressor 10, when the opening of the control valve 37s is reduced, the flow rate of the refrigerant gas, which is introduced from the discharge chamber 15b into the control pressure chamber 35 via the supply passage 37, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b becomes small. Then, when the refrigerant gas is discharged from the control pressure chamber 35 to the suction chamber 15a via the second shaft inner passage 21b, the first shaft inner passage 21a, the pressure adjusting chamber 15c, and the bleed passage 36, the pressure in the control pressure chamber 35 becomes substantially equal to the pressure in the suction chamber 15a. Accordingly, when the pressure difference between the control pressure chamber 35 and the swash plate chamber 24 becomes small, the swash plate 23 pulls the mobile body 32 via the coupling pin 43 by the compression reactive force from the double-headed piston 25 that operates on the swash plate 23, and the mobile body 32 moves to make the bottom part 32a approach the partitioning body 31.

As illustrated in FIG. 4, when the mobile body 32 moves to make the bottom part 32a approach the partitioning body 31, the coupling pin 43 moves by sliding on the inner side of the insertion hole 23h, and the swash plate 23 oscillates around the first oscillation center M1. Then, the lug arm 40 approaches the flange part 39f while oscillating around the second oscillation center M2, following the oscillation of the swash plate 23 around the first oscillation center M1. Accordingly, the inclination angle of the swash plate 23 becomes small, and the stroke of the double-headed piston 25 becomes small so that the discharge volume decreases.

When the opening of the control valve 37s is increased, the flow rate of the refrigerant gas, which is introduced from the discharge chamber 15b into the control pressure chamber 35 via the supply passage 37, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b becomes large. Therefore, the pressure in the control pressure chamber 35 becomes substantially equal to the pressure in the discharge chamber 15b. Accordingly, when the pressure difference between the control pressure chamber 35 and the swash plate chamber 24 becomes large, the mobile body 32 moves to separate the bottom part 32a from the partitioning body 31, while pulling the swash plate 23 via the coupling pin 43.

As illustrated in FIG. 1, when the mobile body 32 moves to separate the bottom part 32a from the partitioning body 31, the coupling pin 43 moves by sliding on the inner side of the insertion hole 23h, and the swash plate 23 oscillates around the first oscillation center M1 in an opposite direction to that when the inclination angle of the swash plate 23 reduces. Then, following the oscillation of the swash plate 23 around the first oscillation center M1, the lug arm 40 oscillates around the second oscillation center M2 in an opposite direction to that when the inclination angle of the swash plate 23 reduces. Accordingly, the inclination angle of the swash plate 23 becomes large, and the stroke of the double-headed piston 25 becomes large so that the discharge volume increases.

Next, the operation of the compressor 10 will be described with reference to FIG. 3.

As illustrated in FIG. 3, following the change of the inclination angle of the swash plate 23, force F0 works from the coupling pin 43 to the swash plate 23, on the perpendicular line L1 of the flat surface part 44a. On the other hand, force F1 as reactive force of the force F0 works from the coupling pin 43 to the mobile body 32, along the perpendicular line L1. In this case, the intersection P1 at which the perpendicular line L1 of the flat surface part 44a and the axial line L of the rotation shaft 21 cross following the change of the inclination angle of the swash plate 23 is located, in the axial direction of the rotation shaft 21, in the region Z1 surrounded by the sliding part 32s as a sliding portion of the rotation shaft 21 and the mobile body 32. At this time, resultant force F3 of the force F1 that works from the coupling pin 43 to the mobile body 32 and the force F2 that moves the mobile body 32 to the axial direction of the rotation shaft 21 by the pressure of the control pressure chamber 35 is generated on a perpendicular line L2 including the intersection P1. Force F4 in the opposite direction that balances with the resultant force F3 is also generated on the perpendicular line L2. As a result, all the forces applied to the mobile body 32 are balanced on the perpendicular line L2 including the intersection P1. Therefore, on the mobile body 32, there occurs no moment that inclines the mobile body 32 to a moving direction. Accordingly, the inclination angle of the swash plate 23 can be smoothly changed.

The inclination θ1 of the flat surface part 44a is set such that, when the inclination angle of the swash plate 23 is a maximum inclination angle, the intersection P1 is located in the region Z1 surrounded by the sliding part 32s. Therefore, there occurs no moment that inclines the mobile body 32 to a moving direction when the inclination angle is the maximum inclination angle at which driving force that is generated in the mobile body 32 becomes maximum. As a result, the inclination angle of the swash plate 23 can be easily changed to the maximum inclination angle and can be smoothly reduced from the maximum inclination angle.

Therefore, in the above embodiment, the following effects can be obtained.

(1) The flat surface part 44a is set such that, viewed from the direction orthogonal to both the axial direction of the rotation shaft 21 and the first direction, the intersection of the perpendicular line L1 of the flat surface part 44a with the axial line L of the rotation shaft 21 is located in the region Z1 surrounded by the sliding part 32s. Following the change of the inclination angle of the swash plate 23, the force F0 works from the coupling pin 43 to the swash plate 23, on the perpendicular line L1 of the flat surface part 44a. On the other hand, the force F1 as reactive force of the force F0 works from the coupling pin 43 to the mobile body 32, along the perpendicular line L1. In this case, the intersection P1 of the perpendicular line L1 of the flat surface part 44a (the force F1 that works from the coupling pin 43 to the mobile body 32) with the axial line L of the rotation shaft 21 following the change of the inclination angle of the swash plate 23 is located, in the axial direction of the rotation shaft 21, in the region Z1 surrounded by the sliding part 32s as a sliding portion of the rotation shaft 21 and the mobile body 32. At this time, the resultant force F3 of the force F1 that works from the coupling pin 43 to the mobile body 32 and the force F2 that moves the mobile body 32 to the axial direction of the rotation shaft 21 by the pressure of the control pressure chamber 35 is generated on the perpendicular line L2 including the intersection P1. The force F4 in the opposite direction that balances with the resultant force F3 is also generated on the perpendicular line L2. As a result, all the forces applied to the mobile body 32 are balanced on the perpendicular line L2 including the intersection P1.

Therefore, on the mobile body 32, there occurs no moment that inclines the mobile body 32 to a moving direction. Accordingly, the inclination angle of the swash plate 23 can be smoothly changed.

(2) The inclination angle θ1 of the flat surface part 44a is set such that, when the inclination angle of the swash plate 23 is a maximum inclination angle, the intersection P1 is located in the region Z1 surrounded by the sliding part 32s. According to this, there occurs no moment that inclines the mobile body 32 to a moving direction when the inclination angle is the maximum inclination angle at which driving force that is generated in the mobile body 32 becomes maximum. As a result, the inclination angle of the swash plate 23 can be easily changed to the maximum inclination angle and can be smoothly reduced from the maximum inclination angle.

(3) The guide surface 44 has the flat surface part 44a that is inclined to the moving direction of the mobile body 32. According to this, the shape of the guide surface 44 can be simplified. That is, because the moment that inclines the mobile body 32 to a moving direction is suppressed, the shape of the guide surface 44 is not complicated. Accordingly, productivity improves.

(4) According to the double-headed piston type swash plate compressor using the double-headed piston 25, the swash plate chamber 24 cannot be made to function as a control chamber for changing the inclination angle of the swash plate 23, unlike the variable displacement type swash plate compressor having a single-headed piston. Therefore, in the present embodiment, the inclination angle of the swash plate 23 is changed by changing the pressure of the control pressure chamber 35 that is partitioned by the mobile body 32. The control pressure chamber 35 is a space smaller than the swash plate chamber 24. Therefore, the volume of the refrigerant gas introduced into the control pressure chamber 35 can be small, so that responsiveness when changing the inclination angle of the swash plate 23 is satisfactory. Further, because the inclination angle of the swash plate 23 can be smoothly changed, the volume of the refrigerant gas introduced into the control pressure chamber 35 can be suppressed to the minimum necessary.

The above embodiment may be changed as follows.

As illustrated in FIG. 5, the flat surface part 44a may be set such that, when the inclination angle of the swash plate 23 is between a minimum inclination angle and a maximum inclination angle, the intersection P1 is located in the region Z1 surrounded by the sliding part 32s. In this case, the inclination θ1 of the flat surface part 44a is set such that the intersection P1 is located in the region Z1, viewed from the direction orthogonal to both the axial direction of the rotation shaft 21 and the first direction, that is, a depth direction on the paper surface in FIG. 5. The inclination θ1 is the inclination to the direction orthogonal to the axial line L of the rotation shaft 21 when the inclination angle of the swash plate 23 is between the minimum inclination angle and the maximum inclination angle. According to this, the mobile body 32 can be smoothly moved between the minimum inclination angle and the maximum inclination angle in which use frequency is the highest. Accordingly, control of the flow rate of the refrigerant gas introduced into the control pressure chamber 35 can be simplified.

As illustrated in FIG. 6, the flat surface part 44a may be set such that, when the inclination angle of the swash plate 23 is a minimum inclination angle, the intersection P1 is located in the region Z1 surrounded by the sliding part 32s. In this case, the inclination θ1 of the flat surface part 44a is set such that the intersection P1 is located in the region Z1 surrounded by the sliding part 32s, viewed from the direction orthogonal to both the axial line L of the rotation shaft 21 and the first direction, that is, a depth direction on the paper surface in FIG. 6. The inclination θ1 is the inclination to the direction orthogonal to the axial line L of the rotation shaft 21 when the inclination angle of the swash plate 23 is the minimum inclination angle. According to this, there occurs no moment that inclines the mobile body 32 to a moving direction when the inclination angle of the swash plate 23 is the minimum inclination angle. Therefore, the inclination angle of the swash plate 23 can be smoothly increased, also at the starting time of the compressor 10.

As illustrated in FIG. 7, the guide surface 44 may have a curved surface part 44b. The curved surface part 44b is formed in an arc shape that passes on a virtual circle R1. Following the change of the inclination angle of the swash plate 23, the force F0 works from the coupling pin 43 to the swash plate 23, on a normal line L3 of the curved surface part 44b. On the other hand, the force F1 as reactive force of the force F0 that works from the coupling pin 43 to the swash plate 23 works from the coupling pin 43 to the mobile body 32 along the normal line L3. In this case, an intersection P2 of the normal line L3 of the curved surface part 44a (the force F1 that works from the coupling pin 43 to the mobile body 32) with the axial line L of the rotation shaft 21 following the change of the inclination angle of the swash plate 23 is located in the region Z1 surrounded by the sliding part 32s. According to this, even when the inclination angle of the swash plate 23 is changed, when the coupling pin 43 is being guided by the curved surface part 44b, the intersection P2 is not easily located outward from the region Z1 surrounded by the sliding part 32s of the rotation shaft 21 and the mobile body 32. As a result, even when the inclination angle of the swash plate 23 is changed, the moment that inclines the mobile body 32 to the moving direction can be easily suppressed, and the inclination angle of the swash plate 23 can be smoothly changed.

As illustrated in FIG. 8, the flat surface part 44a may be set such that, when the inclination angle of the swash plate 23 is a minimum inclination angle, the intersection P1 is located in a region Z2 surrounded by a sliding part 32S that slides on the partitioning body 31, following the movement of the mobile body 32 to the axial direction of the rotation shaft 21. In this case, the inclination θ1 of the flat surface part 44a is set such that the intersection P1 is located in the region Z2, viewed from the direction orthogonal to both the axial line L of the rotation shaft 21 and the first direction, that is, a depth direction on the paper surface in FIG. 8. The inclination θ1 is the inclination to the direction orthogonal to the axial line L of the rotation shaft 21 when the inclination angle of the swash plate 23 is the minimum inclination angle. Further, the inclination θ1 of the flat surface part 44a may be set such that, when the inclination angle of the swash plate 23 is a maximum inclination angle, the intersection P1 is located in the region Z2 surrounded by the sliding part 32S that slides on the partitioning body 31, following the movement of the mobile body 32 to the axial direction of the rotation shaft 21. Further, the inclination θ1 of the flat surface part 44a may be set such that, when the inclination angle of the swash plate 23 is between the minimum inclination angle and the maximum inclination angle, the intersection P1 is located in the region Z2 surrounded by the sliding part 32S that slides on the partitioning body 31, following the movement of the mobile body 32 to the axial direction of the rotation shaft 21.

As illustrated in FIGS. 9 and 10, the guide surface 44 may have a cam surface, which is a combination of the flat surface part 44a and the curved surface part 44b. For example, as illustrated in FIG. 9, when the inclination angle of the swash plate 23 increases to become a maximum inclination angle, the coupling pin 43 is guided by the curved surface part 44b, and as illustrated in FIG. 10, when the inclination angle of the swash plate 23 reduces to become a minimum inclination angle, the coupling pin 43 is guided by the flat surface part 44a. In this case, the inclination θ1 of the flat surface part 44a is set such that, when the inclination angle of the swash plate 23 is the minimum inclination angle, the intersection P1 is located in the region Z1 surrounded by the sliding part 32s, viewed from the direction orthogonal to both the axial line L of the rotation shaft 21 and the first direction, that is, a depth direction on the paper surface in FIG. 10. The inclination θ1 is the inclination to the direction orthogonal to the axial line L of the rotation shaft 21 when the inclination angle of the swash plate 23 is the minimum inclination angle. According to this, there occurs no moment that inclines the mobile body 32 to a moving direction, in a whole range in which the inclination angle of the swash plate 23 can be changed. Accordingly, the inclination angle of the swash plate 23 can be smoothly reduced.

In the swash plate 23, a groove through which the coupling pin 43 can be passed may be formed in place of the insertion hole 23h.

The coupling pin 43 may be fixed to the coupling part 32c by using a screw.

The coupling pin 43 may not be fixed to the coupling part 32c. For example, the coupling pin 43 may be slidably held in an insertion hole of the coupling part 32c by inserting the coupling pin 43 into the insertion hole.

By providing an orifice in the supply passage 37, which communicates the pressure adjusting chamber 15c with the discharge chamber 15b, the electromagnetic control valve 37s may be provided on the bleed passage 36, which communicates the pressure adjusting chamber 15c with the suction chamber 15a.

The compressor 10 may be a single-headed piston type swash plate compressor, which uses a single-headed piston.

The compressor 10 may obtain driving force from an external driving source via a clutch.

VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR

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CPC

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