VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR

BACKGROUND OF THE INVENTION

The present invention relates to a variable displacement type swash plate compressor in which a piston reciprocally moves by stroke according to an inclination angle of a swash plate.

Japanese Laid-Open Patent Publication No. 1-190972 discloses a variable displacement type swash plate compressor of which an inclination angle of the swash plate is changeable by a movable body. According to this compressor, when a refrigerant gas has been introduced into the control pressure chamber within a housing, the pressure in the control pressure chamber is changed. By this arrangement, the movable body moves in the axial direction of the rotation shaft and changes the inclination angle of the swash plate.

Specifically, when the pressure in the control pressure chamber has become high and has approached the pressure in the discharge pressure region, the movable body moves toward one end part of the rotation shaft, and increases the inclination angle of the swash plate. As a result, the stroke of the piston becomes large, and a discharge capacity increases. On the other hand, when the pressure in the control pressure chamber has become low and has approached the pressure in the suction pressure region, the movable body moves toward the other end part of the rotation shaft and decreases the inclination angle of the swash plate. As a result, the stroke of the piston becomes small, and the discharge capacity decreases. The variable displacement type swash plate compressor further includes a capacity control valve that controls the pressure in the control pressure chamber.

The variable displacement type swash plate compressor has a throttle in the middle of the supply passage from the discharge pressure region to the control pressure chamber. The throttle can decrease the flow quantity of the refrigerant gas that is supplied from the discharge pressure region to the control pressure chamber. Accordingly, the inclination angle of the swash plate can be maintained at an intermediate angle between a maximum inclination angle and a minimum inclination angle. Consequently, the compressor can be efficiently operated in the intermediate discharge quantity.

However, as the compressor has the throttle in the middle of the supply passage when an operation command in the maximum discharge capacity is transmitted from the control computer, a pressure in the control pressure chamber cannot be instantly approached to a pressure in the discharge pressure region. Therefore, the inclination angle of the swash plate cannot be instantly changed to the maximum inclination angle, and it takes time until the compressor is operated in the maximum discharge capacity.

Further, the refrigerant gas that is supplied from the discharge pressure region to the control pressure chamber via the supply passage is a compressed refrigerant gas. Therefore, during the operation of the compressor, when the flow quantity of the refrigerant gas supplied to the control pressure chamber increases, the operation efficiency of the compressor decreases.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a variable displacement type swash plate compressor that can instantly change the inclination angle of the swash plate to a maximum inclination angle while maintaining operation efficiency.

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 that includes: a housing; a rotation shaft; a swash plate, which is housed in the housing and rotated by driving force from the rotation shaft, and the inclination angle of the swash plate relative to the rotation shaft varies; a piston, which is engaged with the swash plate; a movable body, which is coupled to the swash plate and changes the inclination angle of the swash plate; a control pressure chamber which is partitioned by the movable body and in which the movable body moves in an axial direction of the rotation shaft to change the inclination angle of the swash plate based on change of a pressure inside the control pressure chamber due to introduction of a refrigerant gas into the control pressure chamber; and a capacity control valve that controls a pressure in the control pressure chamber, wherein the piston reciprocally moves by stroke according to the inclination angle of the swash plate. The capacity control valve includes: a valve body that reciprocally moves by operation of an electromagnetic solenoid; a first valve seat part that has a first valve hole which forms a part of a bleed passage from the control pressure chamber to a suction pressure region; and a second valve seat part that has a second valve hole which forms a part of a supply passage from a discharge pressure region to the control pressure chamber. The valve body has: a first valve part which has an end surface seal part that closes the bleed passage by moving into contact with the first valve seat part; and a second valve part that has an external surface seal part which closes the supply passage by entering the second valve hole. When an opening degree of the first valve part is maximum, a seal length of the external surface seal part along a moving direction of the valve body is shorter than a distance between an end surface seal part and a first valve seat part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a double-headed piston type swash plate compressor according to an embodiment of the present invention;

FIG. 2 is a sectional view of a capacity control valve when an inclination angle of a swash plate is a minimum inclination angle;

FIG. 3 is a sectional view of the capacity control valve when the inclination angle of the swash plate is a maximum inclination angle;

FIG. 4 is a side sectional view of the double-headed piston type swash plate compressor when the inclination angle of the swash plate is a maximum inclination angle;

FIG. 5 is a graph showing a relationship between displacement of a valve body and opening degrees of a first valve part and a second valve part;

FIG. 6A is a partially enlarged sectional view showing a state before a first valve seat part is press-fitted to a press fitting part;

FIG. 6B is a partially enlarged sectional view showing a state that a second valve seat part and an external surface enlarged part are in contact with each other;

FIG. 7A is a partially enlarged sectional view showing a state that a swash plate of a capacity control valve according to other example is at a minimum inclination angle;

FIG. 7B is a partially enlarged sectional view showing a state that the swash plate is at a maximum inclination angle;

FIG. 8 is a graph showing a relationship between displacement of a valve body and opening degrees of a first valve part and a second valve part;

FIG. 9A is a partially enlarged sectional view of a capacity control valve according to other example; and

FIG. 9B is a partially enlarged sectional view showing a state before a press-fit member is press-fitted to a press fitting part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a variable displacement type swash plate compressor according to an embodiment of the present invention will be described with reference to FIG. 1 to FIG. 6B by taking an example of a compressor that is used in a vehicle air conditioner. In the following description, a front and rear direction and an up and down direction will be defined respectively as shown in FIG. 1.

As shown in FIG. 1, a housing 11 of a variable displacement type swash plate compressor 10 includes a first cylinder block 12, a second cylinder block 13, a front housing 14 joined to the front end of the first cylinder block 12, and a rear housing 15 joined to the rear end of the second cylinder block 13. The first cylinder block 12 is arranged in front of the second cylinder block 13 and is joined to the second cylinder block 13.

A first valve/port forming body 16 is arranged between the front housing 14 and the first cylinder block 12. A second valve/port forming body 17 is arranged 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 arranged at the outer periphery side 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 arranged in a center part of the rear housing 15, and the suction chamber 15a is arranged at an outer periphery side of the pressure adjusting chamber 15c. The discharge chamber 15b is arranged at an outer periphery side of the suction chamber 15a. The discharge chambers 14b and 15b are connected to each other via a discharge passage not shown. The discharge passage is connected to an external refrigerant circuit not shown. The discharge chambers 14b and 15b are discharge pressure regions.

The first valve/port forming body 16 has a suction port 16a that is communicated with the suction chamber 14a, and a discharge port 16b that is communicated with the discharge chamber 14b. The second valve/port forming body 17 has a suction port 17a that is communicated with the suction chamber 15a, and a discharge port 17b that is communicated with the discharge chamber 15b. The suction port 16a and 17a have suction valve mechanisms not shown. The discharge ports 16b and 17b have discharge valve mechanisms not shown.

A rotation shaft 21 having a center axial line L is rotationally supported in the housing 11. Both ends in the longitudinal direction of the rotation shaft 21 are arranged toward the front and rear direction of the housing 11. A front end of the rotation shaft 21 is inserted through an axial hole 12h which is formed on the first cylinder block 12, and the front end is also arranged in the front housing 14. The rear end of the rotation shaft 21 is inserted through an axial hole 13h which is formed on the second cylinder block 13, and the rear end is also arranged in the pressure adjusting chamber 15c.

The front end of the rotation shaft 21 is rotationally supported to the axial hole 12h of the first cylinder block 12. The rear end of the rotation shaft 21 is rotationally supported to the axial hole 13h of the second cylinder block 13. A lip seal type shaft seal device 22 is arranged between the front housing 14 and the rotation shaft 21. An engine E of a vehicle as an external driving source is work-coupled to the front end of the rotation shaft 21 via a power transmission mechanism PT. The power transmission mechanism PT is a normally transmission type clutchless mechanism that is configured by combining a belt and a pulley.

A crank chamber 24 partitioned by the first cylinder block 12 and the second cylinder block 13 is formed in the housing 11. A swash plate 23 having an insertion hole 23a is housed in the crank chamber 24. The swash plate 23 is installed on the rotation shaft 21 by inserting the rotation shaft 21 through the insertion hole 23a. The swash plate 23 can rotate by obtaining driving force from the rotation shaft 21 and can also tilt with respect to the axis of the rotation shaft 21.

A plurality of first cylinder bores 12a is formed on the first cylinder block 12. The plurality of first cylinder bores 12a extends in the axial direction of the first cylinder block 12 and is also arranged around the rotation shaft 21. FIG. 1 shows only one first cylinder bore 12a. Each of the plurality of first cylinder bores 12a is communicated with the suction chamber 14a via the suction port 16a and is communicated with the discharge chamber 14b via the discharge port 16b. A plurality of second cylinder bores 13a is formed on the second cylinder block 13. The plurality of second cylinder bores 13a extends in the axial direction of the second cylinder block 13 and is also arranged around the rotation shaft 21. FIG. 1 shows only one second cylinder bore 13a. Each of the plurality of second cylinder bores 13a is communicated with the suction chamber 15a via the suction port 17a and is communicated with the discharge chamber 15b via the discharge port 17b. The first cylinder bore 12a and the second cylinder bore 13a are respectively arranged to form a pair in the front and rear direction. In the first cylinder bore 12a and the second cylinder bore 13a that form the pair, double-headed pistons 25 as pistons are housed reciprocally in the front and rear direction.

Each double-headed piston 25 is engaged with the outer peripheral part of the swash plate 23 via a pair of shoes 26. When the rotation shaft 21 has rotated, rotational motion of the swash plate 23 is transformed into reciprocal linear motion of the double-headed pistons 25 via the shoes 26. In each first cylinder bore 12a, the first compression chamber 20a is partitioned by the double-headed pistons 25 and the first valve/port forming body 16. In each second cylinder bore 13a, the second compression chamber 20b is partitioned by the double-headed pistons 25 and the second valve/port forming body 17.

A first large diameter hole 12b having a larger diameter than that of the axial hole 12h and being continuous with the axial hole 12h is formed on the first cylinder block 12. The first large diameter hole 12b is communicated with the crank chamber 24. The crank chamber 24 and the suction chamber 14a are communicated with each other by a suction passage 12c that passes through the first cylinder block 12 and the first valve/port forming body 16.

A second large diameter hole 13b having a larger diameter than that of the axial hole 13h is formed on the second cylinder block 13 as well as being continuous with the axial hole 13h. The second large diameter hole 13b is communicated with the crank chamber 24. The crank chamber 24 and the suction chamber 15a are communicated with each other by a suction passage 13c that passes through the second cylinder block 13 and the second valve/port forming body 17.

A suction opening 13s is formed on the peripheral wall of the second cylinder block 13. The suction opening 13s is connected to the external refrigerant circuit. The refrigerant gas is suctioned into the crank chamber 24 from the external refrigerant circuit via the suction opening 13s, and is thereafter suctioned into the suction chamber 14a via the suction passage 12c and into the suction chamber 15a via the suction passage 13c. Therefore, the pressures in the suction chambers 14a and 15a and the pressure in the crank chamber 24 become substantially equal, and the suction chambers 14a and 15a and the crank chamber 24 become a suction pressure region.

An annular flange part 21f is installed in a protruding manner on the outer peripheral surface of the rotation shaft 21. The flange part 21f is arranged in the first large diameter hole 12b. A first thrust bearing 27a is installed near the front end of the rotation shaft 21. The first thrust bearing 27a is arranged between the flange part 21f and the first cylinder block 12. A cylindrical supporting member 39 is press-fitted to the vicinity of the rear end of the rotation shaft 21. An annular flange part 39f is provided installed in a protruding manner from the outer peripheral surface of the supporting member 39. The flange part 39f is arranged in the second large diameter hole 13b. The second thrust bearing 27b is arranged between the flange part 39f and the second cylinder block 13.

An annular fixed body 31 is fixed to the rotation shaft 21. Therefore, the fixed body 31 can rotate together with the rotation shaft 21. The fixed body 31 is arranged between the flange part 21f and the swash plate 23. A bottomed cylindrical movable body 32 is arranged between the flange part 21f and the fixed body 31. The movable body 32 can move to the fixed body 31 in the axial direction of the rotation shaft 21.

The movable body 32 is formed by a circular annular bottom part 32a and a cylinder part 32b. An insertion hole 32e through which the rotation shaft 21 is inserted is formed on the bottom part 32a. The cylinder part 32b extends from the outer peripheral edge of the bottom part 32a along the axial direction of the rotation shaft 21. The inner peripheral surface of the cylinder part 32b can slide to the outer peripheral edge of the fixed body 31. Therefore, the movable body 32 can rotate together with the rotation shaft 21 by the fixed body 31. The interface between the inner peripheral surface of the cylinder part 32b and the outer peripheral edge of the fixed body 31 is sealed by a seal member 33. The interface between the insertion hole 32e and the rotation shaft 21 is sealed by a seal member 34. A control pressure chamber 35 is partitioned between the fixed body 31 and the movable body 32.

A first shaft inner passage 21a is formed in the rotation shaft 21. The first shaft inner passage 21a extends along the axial direction of the rotation shaft 21. The rear end of the first shaft inner passage 21a is opened to the pressure adjusting chamber 15c. A second shaft inner passage 21b is formed on the rotation shaft 21. The second shaft inner passage 21b extends along the radial direction of the rotation shaft 21. The lower end of the second shaft inner passage 21b is communicated with the front end of the first shaft inner passage 21a. The upper end of the second shaft inner passage 21b is opened to the control pressure chamber 35. Therefore, the control pressure chamber 35 and the pressure adjusting chamber 15c are communicated with each other via the first shaft inner passage 21a and the second shaft inner passage 21b.

In the crank chamber 24, a lug arm 40 is arranged between the swash plate 23 and the flange part 39f. The lug arm 40 is formed in approximately an L shape. A weight part 40a is formed at the upper end of the lug arm 40. The upper end of the weight part 40a passes through a groove part 23b of the swash plate 23 and projects to the front of the swash plate 23.

A first pin 41 that is arranged to cross the groove part 23b is installed on the swash plate 23. The upper end of the lug arm 40 is coupled to the vicinity of the upper end of the swash plate 23 by the first pin 41. Therefore, the vicinity of the upper end of the lug arm 40 is supported to the swash plate 23 so as to be able to swing around a first swing center M1 as an axis core of the first pin 41. The vicinity of the lower end of the lug arm 40 is coupled to the supporting member 39 by a second pin 42. Therefore, the vicinity of the lower end of the lug arm 40 is supported to the supporting member 39 so as to be able to swing around a second swing center M2 as an axis core of the second pin 42.

A coupling part 32c projects from the front end of the cylinder part 32b of the movable body 32 toward the swash plate 23. An insertion hole 32h through which a third pin 43 is inserted is formed on the coupling part 32c. An insertion hole 23h through which the third pin 43 is inserted is formed near the lower end of the swash plate 23. The third pin 43 couples between the coupling part 32c of the movable body 32 and the lower end of the swash plate 23.

The pressure in the control pressure chamber 35 is controlled by the supply of the refrigerant gas from the discharge chamber 15b to the control pressure chamber 35 and the discharge of the refrigerant gas from the control pressure chamber 35 to the suction chamber 15a. That is, the refrigerant gas that is supplied to the control pressure chamber 35 is a control gas that controls the pressure in the control pressure chamber 35. The movable body 32 moves to the fixed body 31 in the axial direction of the rotation shaft 21, based on a pressure difference between the pressure in the control pressure chamber 35 and the pressure in the crank chamber 24. An electromagnetic system capacity control valve 50 that controls the pressure in the control pressure chamber 35 is installed in the rear housing 15. The capacity control valve 50 is electrically connected to a control computer 50c. An air conditioner switch 50s is signal-connected to the control computer 50c.

As shown in FIG. 2, a valve housing 50h of the capacity control valve 50 has a first housing 51 having a cylindrical shape and a second housing 52 having a cylindrical shape. An electromagnetic solenoid 53 is housed in the first housing 51. The second housing 52 is installed in the first housing 51. The electromagnetic solenoid 53 has a fixed iron core 54 and a variable iron core 55. The variable iron core 55 is pulled to the fixed iron core 54 based on excitation by current supply to a coil 53c. That is, electromagnetic force of the electromagnetic solenoid 53 acts to pull the variable iron core 55 toward the fixed iron core 54. The electromagnetic solenoid 53 operates by receiving conduction control of the control computer 50c, specifically, by receiving duty ratio control. A spring 56 is arranged between the fixed iron core 54 and the variable iron core 55. The spring 56 biases the variable iron core 55 to a direction of separating the variable iron core 55 from the fixed iron core 54.

A driving force transmitting rod 57 is installed on the variable iron core 55. The driving force transmitting rod 57 can move together with the variable iron core 55. The fixed iron core 54 has a small diameter part 54a and a large diameter part 54b having a larger diameter than that of the small diameter part 54a. The small diameter part 54a is arranged at the inner side of the coil 53c. The large diameter part 54b projects from the opening of the first housing 51 at the opposite side of the variable iron core 55. A concave part 54c is formed on the end surface of the large diameter part 54b at the opposite side of the small diameter part 54a. A step part 541c is formed on the inner wall of the concave part 54c. The second housing 52 is fitted to and fixed to the concave part 54c in the state that the second housing 52 is brought into contact with the step part 541c.

A housing chamber 59 is formed at the opposite side of the electromagnetic solenoid 53 in the second housing 52. A pressure sensing mechanism 60 is housed in the housing chamber 59. The pressure sensing mechanism 60 includes a bellows 61, a pressure receiving body 62 that is joined to the upper end of the bellows 61, a coupled body 63 that is coupled to the lower end of the bellows 61, and a spring 64 that is laid in the bellows 61. The pressure receiving body 62 is press-fitted to the opening of the second housing 52 at the opposite side of the first housing 51. The spring 64 biases the coupled body 63 to a direction of separating the coupled body 63 away from the pressure receiving body 62.

A stopper 62a is formed on the pressure receiving body 62. The stopper 62a projects from the lower surface of the pressure receiving body 62 toward the coupled body 63. A stopper 63a is formed on the coupled body 63. The stopper 63a projects from the upper surface of the coupled body 63 toward the stopper 62a of the pressure receiving body 62. The stopper 62a of the pressure receiving body 62 and the stopper 63a of the coupled body 63 define a shortest length of the bellows 61.

A valve chamber 65 is formed between the housing chamber 59 in the second housing 52 and the first housing 51. The valve chamber 65 is communicated with the housing chamber 59. The diameter of the valve chamber 65 is smaller than the diameter of the housing chamber 59. A supply chamber 66 is formed between the valve chamber 65 in the second housing 52 and the first housing 51. The supply chamber 66 is communicated with the valve chamber 65. The diameter of the supply chamber 66 is smaller than the diameter of the valve chamber 65. A step part 52f is formed between the valve chamber 65 and the supply chamber 66 in the second housing 52.

An annular first valve seat part 71 is arranged near the housing chamber 59 in the valve chamber 65. The first valve seat part 71 is a separate body from the second housing 52. A first valve hole 71h is formed at the center of the first valve seat part 71. The first valve hole 71h communicates between the valve chamber 65 and the housing chamber 59. An annular second valve seat part 72 is arranged near the supply chamber 66 in the valve chamber 65. The second valve seat part 72 is a separate body from the second housing 52. A second valve hole 72h is formed at the center of the second valve seat part 72. The second valve hole 72h communicates between the valve chamber 65 and the supply chamber 66.

A biasing spring 73 as a biasing member is arranged between the first valve seat part 71 and the second valve seat part 72 in the valve chamber 65. The biasing spring 73 biases the second valve seat part 72 toward the step part 52f of the second housing 52. The second valve seat part 72 is positioned by being pressed to the step part 52f by the biasing spring 73. The first valve seat part 71 is press-fitted to the inner surface of the valve chamber 65 near the housing chamber 59. Therefore, the inner surface of the valve chamber 65 near the housing chamber 59 forms a press fitting part 65a to which the first valve seat part 71 is press-fitted.

A rear pressure chamber 67 is partitioned between the concave part 54c of the fixed iron core 54 and the lower surface of the second housing 52. The rear pressure chamber 67 and the housing chamber 59 are communicated with each other via a communication passage 52r that is formed on the second housing 52.

A valve body 74 is housed in the second housing 52. The valve body 74 extends from the housing chamber 59 to the rear pressure chamber 67. The valve body 74 has a first valve part 75 and a second valve part 76. Both the first valve part 75 and the second valve part 76 are housed in the valve chamber 65. The first valve part 75 has an end surface seal part 75s. The end surface seal part 75s is brought into contact with a seat part 71e as an end surface of the first valve seat part 71 around the first valve hole 71h. The first valve part 75 has an annular projecting part 75f. The projecting part 75f projects above the end surface seal part 75s and also enters the first valve hole 71h. The second valve part 76 has an external surface seal part 76s that enters the second valve hole 72h.

The valve body 74 has an annular external surface enlarged part 74a. The external surface enlarged part 74a is formed to increase in size in in a tapered manner and to be inclined conically from the external surface seal part 76s toward the end surface seal part 75s. The valve body 74 has a reduced-diameter part 74b having a smaller diameter than that of the external surface seal part 76s. The reduced-diameter part 74b is arranged in the supply chamber 66. The valve body 74 further has an enlarged-diameter part 74c having a larger diameter than that of the reduced-diameter part 74b. The enlarged-diameter part 74c is continuous with the reduced-diameter part 74b. The enlarged-diameter part 74c projects into the rear pressure chamber 67 by moving beyond the bottom part of the second housing 52. An annular first working surface 741, which has the form of a step, is formed between the external surface seal part 76s and the reduced-diameter part 74b of the valve body 74. A second working surface 742, which has the form of an annular step, is formed between the reduced-diameter part 74b and the enlarged-diameter part 74c of the valve body 74. The pressure receiving surface of the first working surface 741 is the same as the pressure receiving surface of the second working surface 742.

The upper end of the driving force transmitting rod 57 projects into the rear pressure chamber 67 by moving beyond the fixed iron core 54. The upper end of the driving force transmitting rod 57 is brought into contact with the enlarged-diameter part 74c of the valve body 74.

A rod 74e projects from the upper end surface of the valve body 74 that faces the housing chamber 59. The upper end of the rod 74e is separably coupled to the coupled body 63. A return spring 77 is arranged between the projecting part 75f and the coupled body 63. The return spring 77 biases the valve body 74 toward the electromagnetic solenoid 53.

A communication hole 521 that is communicated with the housing chamber 59 is formed in the second housing 52. A communication hole 522 that is communicated with the valve chamber 65 is formed in the second housing 52. A communication hole 523 that communicates with the supply chamber 66 is formed in the second housing 52. The housing chamber 59 is communicated with the suction chamber 15a via the communication hole 521 and the passage 81. The valve chamber 65 is communicated with the pressure adjusting chamber 15c via the communication hole 522 and the passage 82. Therefore, the second shaft inner passage 21b, the first shaft inner passage 21a, the pressure adjusting chamber 15c, the passage 82, the communication hole 522, the valve chamber 65, the first valve hole 71h, the housing chamber 59, the valve chamber 521, and the passage 81 form a bleed passage that extends from the control pressure chamber 35 to the suction chamber 15a.

The supply chamber 66 is communicated with the discharge chamber 15b via the communication hole 523 and the passage 83. The discharge chamber 15b is communicated with the control pressure chamber 35 via the passage 83, the communication hole 523, the supply chamber 66, the second valve hole 72h, the valve chamber 65, the communication hole 522, the passage 82, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b. Therefore, the passage 83, the communication hole 523, the supply chamber 66, the second valve hole 72h, the valve chamber 65, the communication hole 522, the passage 82, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b form a supply passage from the discharge chamber 15b to the control pressure chamber 35.

The bellows 61 expands and contracts in a moving direction of the valve body 74 by sensing the pressure applied to the bellows 61 in the housing chamber 59 and the pressure applied to the enlarged-diameter part 74c of the valve body 74 in the rear pressure chamber 67. Expansion and contraction of the bellows 61 positions the valve body 74 and contributes to the control of the opening degrees of the first valve part 75 and the second valve part 76. The opening degrees of the first valve part 75 and the second valve part 76 are determined by the balance between the electromagnetic force generated by the electromagnetic solenoid 53, the biasing force of the spring 56, and the biasing force of the pressure sensing mechanism 60.

The first valve part 75 is in the closed valve state for closing the bleed passage when the projecting part 75f enters the first valve hole 71h. On the other hand, the first valve part 75 is in the opened valve state for opening the bleed passage when the projecting part 75 exits from the first valve hole 71h. The second valve part 76 is in the closed valve state for closing the supply passage when the external surface seal part 76s enters the second valve hole 72h. On the other hand, the second valve part 76 is in the opened valve state for opening the supply passage when the external surface seal part 76s exits from the second valve hole 72h.

In the variable displacement type swash plate compressor 10, in the state in which the air conditioner switch 50s has been turned off and current to the electromagnetic solenoid 53 has been stopped, the variable iron core 55 is separated from the fixed iron core 54 by the spring 56, and the valve body 74 is moved toward the electromagnetic solenoid 53 by the return spring 77. Accordingly, the end surface seal part 75s is separated from the seat part 71e, and the projecting part 75f can exit from the first valve hole 71h. In this state, the end surface seal part 75s is most separated from the seat part 71e and the opening degree of the first valve part 75 is maximum.

At this time, the external surface seal part 76s enters the second valve hole 72h, so that the interface between the external surface seal part 76s and the second valve hole 72h is sealed. A seal length L1 of the external surface seal part 76s along the moving direction of the valve body 74 is shorter than a distance L2 between the end surface seal part 75s and the seat part 71e along the moving direction of the valve body 74. In the present embodiment, when the opening degree of the first valve part 75 is maximum, the seal length L1 is the same as a distance L3 along the moving direction of the valve body 74 between the projecting part 75f and the first valve seat part 71. Further, because the pressure receiving surface of the first working surface 741 is the same as the pressure receiving surface of the second working surface 742, the valve body 74 is suppressed from moving by sensing the pressure of the refrigerant gas supplied to the supply chamber 66.

An increase in the opening degree of the first valve part 75 causes an increase in the flow quantity of the refrigerant gas that 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, the passage 82, the communication hole 522, the valve chamber 65, the first valve hole 71h, the housing chamber 59, the communication hole 521, and the passage 81. As a result, the pressure in the control pressure chamber 35 approaches the pressure in the suction chamber 15a.

As shown in FIG. 1, when the pressure in the control pressure chamber 35 approaches the pressure in the suction chamber 15a and the pressure difference between the pressure in the control pressure chamber 35 and the pressure in the crank chamber 24 has become small, the swash plate 23 pulls the movable body 32 by the compression reaction force from the double-headed pistons 25 that operates to the swash plate 23, and the movable body 32 moves to set the bottom part 32a closer to the fixed body 31. Then, the swash plate 23 swings around the first swing center M1. Following this vibration, the lug arm 40 swings around the first vibration center M1 and around the second swing center M2 respectively, and the lug arm 40 approaches the flange part 39f of the supporting member 39. Consequently, the inclination angle of the swash plate 23 becomes small, the stroke of the double-headed pistons 25 becomes small, and the discharge capacity decreases. When the inclination angle of the swash plate 23 has reached a minimum inclination angle, the lug arm 40 is brought into contact with the flange part 39f of the supporting member 39. When the lug arm 40 has been brought into contact with the flange part 39f, the inclination angle of the swash plate 23 is maintained at a minimum inclination angle.

As shown in FIG. 3, in the variable displacement type swash plate compressor 10, when the air conditioner switch 50s has been turned on and a current has been supplied to the electromagnetic solenoid 53, the variable iron core 55 is pulled to the fixed iron core 54 against the spring force of the spring 56 by the electromagnetic force of the electromagnetic solenoid 53. Then, the driving force transmitting rod 57 presses the valve body 74 against the spring force of the return spring 77.

When the valve body 74 has been pressed by the driving force transmitting rod 57, the projecting part 75f enters the first valve hole 71h, and the external surface seal part 76s exits from the second valve hole 72h. When the valve body 74 has been further pressed, the end surface seal part 75s is brought into contact with the seat part 71e, and the quantity of the external surface seal part 76s that exits from the second valve hole 72h becomes maximum. This causes decrease in the flow quantity of the refrigerant gas that 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, the passage 82, the communication hole 522, the valve chamber 65, the first valve hole 71h, the housing chamber 59, the communication hole 521, and the passage 81. Then, the refrigerant gas is supplied from the discharge chamber 15b to the control pressure chamber 35 via the passage 83, the communication hole 523, the supply chamber 66, the second valve hole 72h, the valve chamber 65, the communication hole 522, the passage 82, the pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b. As a result, the pressure in the control pressure chamber 35 approaches the pressure in the discharge chamber 15b.

As shown in FIG. 4, when the pressure in the control pressure chamber 35 approaches the pressure in the discharge chamber 15b and the pressure difference between the pressure in the control pressure chamber 35 and the pressure in the crank chamber 24 has become large, the movable body 32 moves to separate the bottom part 32a from the fixed body 31 while pulling the swash plate 23. Then, the swash plate 23 swings in the direction opposite to the direction at the time of reduction in the inclination angle of the inclination angle 23, around the first swing center M1. Then, the lug arm 40 swings in the direction opposite to the direction at the time of reduction in the inclination angle of the swash plate 23 around the first swing center M1 and around the second swing center M2, respectively, and the lug arm 40 is separated from the flange part 39f of the supporting member 39. Accordingly, the inclination angle of the swash plate 23 becomes large, the stroke of the double-headed pistons 25 becomes large, and the discharge capacity increases. When the inclination angle of the swash plate 23 has reached the maximum inclination angle, the movable body 32 is brought into contact with the flange part 21f. When the movable body 32 has been brought into contact with the flange part 21f, the inclination angle of the swash plate 23 is maintained at the maximum inclination angle.

Next, the operation of the variable displacement type swash plate compressor 10 will be described with reference to FIG. 5 to FIG. 6A.

A solid line in FIG. 5 expresses a relationship between displacement of the valve body 74 and opening degrees of the first valve part 75 and the second valve part 76 according to the present embodiment. A two-dot chain line in FIG. 5 expresses a relationship between displacement of the valve body 74 and opening degrees of the first valve part 75 and the second valve part 76 according to a comparative example. In the comparative example, the first valve part 75 does not have the projecting part 75f, and the second valve part 76 has an end surface seal part that closes the supply passage by being brought into contact with the end surface of the second valve seat part 72 around the second valve hole 72h.

As shown in FIG. 5, in the present embodiment, the opening degree of the second valve part 76 when the first valve part 75 is moving to the seat part 71e from the state of a maximum opening degree of the first valve part 75 is smaller than the opening degree in the comparative example. As a result, during the operation of the variable displacement type swash plate compressor 10, the flow quantity of the refrigerant gas supplied to the control pressure chamber 35 becomes small.

Then, when the end surface seal part 75s of the first valve part 75 has been brought into contact with the seat part 71e, the external surface seal part 76s of the second valve part 76 exits from the second valve hole 72h, and the opening degree of the second valve part 76 becomes maximum. Accordingly, as the flow quantity of the refrigerant gas supplied from the discharge chamber 15b to the control pressure chamber 35 via the supply passage increases, the inclination angle of the swash plate 23 is instantly changed to the maximum inclination angle. As a result, the variable displacement type swash plate compressor 10 is operated in the maximum discharge capacity.

FIG. 6A shows a state that the second valve seat part 72 is mounted on the step part 52f of the second housing 52, the valve body 74 is housed in the second housing 52, and the biasing spring 73 is mounted on the second valve seat part 72. In this state, the first valve seat part 71 is press-fitted to the press fitting part 65a. Before the first valve seat part 71 is press-fitted to the press fitting part 65a, the length of the biasing spring 73 is a free length. When the first valve seat part 71 has been press-fitted to the press fitting part 65a, biasing force that presses the second valve seat part 72 to the step part 52f occurs in the biasing spring 73.

FIG. 6B shows a state that the valve body 74 is being pressed toward the bottom part of the second housing 52 in the state that the first valve seat part 71 has been press-fitted to the press fitting part 65a and the second valve seat part 72 has been pressed to the step part 52f by the biasing spring 73. In this state, the external surface enlarged part 74a is in contact with the inner surface of the second valve hole 72h and the axis of the second valve seat part 72 coincides with the axis of the valve body 74. As a result, leakage of the refrigerant gas between the second valve hole 72h and the external surface seal part 76s of the second valve part 76 can be suppressed.

Accordingly, in the present embodiment, the following effects can be obtained.

(1) The valve body 74 has the first valve part 75 and the second valve part 76. The first valve part 75 has the end surface seal part 75s that is brought into contact with the seat part 71e of the first valve seat part 71 and closes the bleed passage. The second valve part 76 has the external surface seal part 76s that enters the second valve hole 72h and closes the supply passage. When the opening degree of the first valve part 75 is maximum, the seal length L1 of the external surface seal part 76s along the moving direction of valve body 74 is shorter than the distance L2 between the end surface seal part 75s and the seat part 71e along the moving direction of the valve body 74. According to this configuration, as compared with the above comparative example, the opening degree of the second valve part 76 when the first valve part 75 is moving to the seat part 71e from the state of a maximum opening degree of the first valve part 75 can be made small. As a result, during the operation of the variable displacement type swash plate compressor 10, the flow quantity of the refrigerant gas supplied to the control pressure chamber 35 can be made small. Further, when the end surface seal part 75s of the first valve part 75 has been brought into contact with the seat part 71e, the external surface seal part 76s of the second valve part 76 exits from the second valve hole 72h, and the opening degree of the second valve hole 76 becomes maximum. Accordingly, because the flow quantity of the refrigerant gas that is supplied from the discharge chamber 15b to the control pressure chamber 35 via the supply passage increases, the inclination angle of the swash plate 23 can be instantly changed to the maximum inclination angle. As a result, the inclination angle of the swash plate 23 can be instantly changed to a maximum inclination angle while maintaining the operation efficiency of the variable displacement type swash plate compressor 10.

(2) The valve body 74 has the projecting part 75f that projects from the end surface seal part 75s. The projecting part 75f enters the first valve hole 71h and closes the bleed passage. When the projecting part 75f has entered the first valve hole 71h, the second valve part 76 is opened. According to this configuration, as compared with the case where the valve body 74 does not have the projecting part 75f, the timing when the bleed passage is closed during the operation of the variable displacement type swash plate compressor 10 can be made earlier. Therefore, the discharge quantity of the refrigerant gas from the control pressure chamber 35 to the suction chamber 15a via the bleed passage can be made small. As a result, it is possible to decrease the flow quantity of the refrigerant gas that is supplied from the discharge chamber 15b to the control pressure chamber 35 via the supply passage in order to set the inclination angle of the swash plate 23 to a maximum inclination angle. Accordingly, the operation efficiency of the variable displacement type swash plate compressor 10 improves.

(3) The second valve seat part 72 is a separate body from the second housing 52. Further, the biasing spring 73 is arranged between the first valve seat part 71 and the second valve seat part 72 in the second housing 52. The biasing spring 73 biases the second valve seat part 72 toward the step part 52f of the second housing 52. According to this configuration, as compared with the case where the second valve seat part 72 has been integrally formed in the second housing 52, the clearance between the second valve hole 72h and the external surface seal part 76s of the second valve part 76 can be easily adjusted. Accordingly, leakage of the refrigerant gas between the second valve hole 72h and the external surface seal part 76s of the second valve part 76 can be suppressed.

(4) The valve body 74 has the external surface enlarged part 74a. The external surface enlarged part 74a is formed to have a tapered shape from the external surface seal part 76s to the end surface seal part 75s. According to this configuration, by contacting the external surface enlarged part 74a with the inner surface of the second valve hole 72h in the state that the second valve seat part 72 has been housed in the second housing 52, the axis of the second valve seat part 72 and the axis of the valve body 74 coincide with each other. That is, centering of the second valve seat part 72 and the valve body 74 can be performed easily. Consequently, leakage of the refrigerant gas between the second valve hole 72h and the external surface seal part 76s of the second valve part 76 can be suppressed.

(5) The first valve seat part 71 is a separate body from the second housing 52. Further, the first valve seat part 71 is press-fitted to the press fitting part 65a of the second housing 52. Before the first valve seat part 71 is press-fitted to the press fitting part 65a, the length of the biasing spring 73 is a free length. According to this configuration, in press-fitting the first valve seat part 71 to the press fitting part 65a, the biasing force of the biasing spring 73 does not act on the first valve seat part 71. Therefore, the first valve seat part 71 can be easily press-fitted to the press fitting part 65a.

(6) In the variable displacement type swash plate compressor 10 that employs the double-headed pistons 25, the crank chamber 24 cannot be made to function as a control pressure chamber for changing the inclination angle of the swash plate 23, unlike the variable displacement type swash plate compressor that employs a single-headed piston. In this respect, in the above variable displacement type swash plate compressor 10, 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 movable body 32. The control pressure chamber 35 has a space smaller than that of the crank chamber 24. Therefore, the quantity of the refrigerant gas that is introduced into the control pressure chamber 35 can be small, and the operation efficiency of the variable displacement type swash plate compressor 10 improves.

The above embodiment may be also changed as follows.

As shown in FIG. 7A and FIG. 7B, the projecting part 75f may be omitted from the end surface seal part 75s. A valve body 74A becomes in the closed valve state for closing the bleed passage, by bringing the end surface seal part 75s of the first valve part 75 into contact with the seat part 71e. The valve body 74A becomes in the opened valve state for opening the bleed passage, by separating the end surface seal part 75s from the seat part 71e.

A solid line in FIG. 8 expresses a relationship between displacement of the valve body 74A and opening degrees of the first valve part 75 and the second valve part 76 according to the present embodiment. A two-dot chain line in FIG. 8 expresses a relationship between displacement of the valve body 74A and opening degrees of the first valve part 75 and the second valve part 76 in the comparative example. In the comparative example, the second valve part 76 has the end surface seal part that closes the supply passage by being brought into contact with the end surface of the second valve seat part 72 around the second valve hole 72h.

As shown in FIG. 8, when the first valve part 75 is moving toward the seat part 71e from the state of a maximum opening degree of the first valve part 75, the opening degree of the second valve part 76 is smaller than the opening degree in the comparative example. As a result, during the operation of the variable displacement type swash plate compressor 10, the flow quantity of the refrigerant gas supplied to the control pressure chamber 35 becomes small.

Then, when the end surface seal part 75s of the first valve part 75 has been brought into contact with the seat part 71e, the external surface seal part 76s of the second valve part 76 exits from the second valve hole 72h, and the opening degree of the second valve hole 76 becomes maximum. Accordingly, because there is the increase in the flow quantity of the refrigerant gas supplied from the discharge chamber 15b to the control pressure chamber 35 via the supply passage, the inclination angle of the swash plate 23 is instantly changed to the maximum inclination angle. As a result, the variable displacement type swash plate compressor 10 is operated in the maximum discharge capacity.

As shown in FIG. 9A, an annular press-fit member 78 may be further press-fitted to the press fitting part 65a. Further, the first valve seat part 71 may not be press-fitted to the press fitting part 65a. The first valve seat part 71, the biasing spring 73, and the second valve seat part 72 are arranged between the step part 52f and the press-fit member 78.

As shown in FIG. 9B, before the press-fit member 78 is press-fitted to the press fitting part 65a, the length of the biasing spring 73 may be a free length. According to this configuration, in press-fitting the press-fit member 78 to the press fitting part 65a, the biasing force of the biasing spring 73 does not work on the press-fit member 78. Therefore, the press-fit member 78 can be easily press-fitted to the press fitting part 65a.

When the press-fit member 78 is press-fitted to the press fitting part 65a, the first valve seat part 71 is installed on the press-fit member 78 in the state of being urged against the press-fit member 78 by the biasing spring 73. In this case, in order to install the first valve seat part 71, the first valve seat part 71 need not be press-fitted to the press fitting part 65a. Therefore, the axis of the first valve seat part 71 and the axis of the valve body 74 easily coincide with each other without having the first valve seat part 71 constrained by the second housing 52.

Before the first valve seat part 71 is press-fitted to the press fitting part 65a, the length of the biasing spring 73 may not be a free length, and the first valve seat part 71 may be energized by the biasing spring 73.

The external surface enlarged part 74a may be omitted from between the external surface seal part 76s and the end surface seal part 75s of the valve body 74.

The second valve seat part 72 may be integrally formed with the second housing 52.

The driving force transmitting rod 57 may be integrally formed with the valve body 74.

The housing chamber 59 may be communicated with the suction chamber 14a via the communication hole 521 and the passage 81. That is, it is sufficient that the bleed passage from the control pressure chamber 35 to the suction pressure region has been formed.

The discharge chamber 14b and the control pressure chamber 35 may be communicated with each other via the passage 83, the communication hole 523, the supply chamber 66, the second valve hole 72h, valve chamber 65, communication hole 522, the passage 82, pressure adjusting chamber 15c, the first shaft inner passage 21a, and the second shaft inner passage 21b.

The driving force may be obtained from the external driving source via a clutch.

The variable displacement type swash plate compressor 10 may be a single-head piston type swash plate compressor that employs a single-headed piston.

VARIABLE DISPLACEMENT TYPE SWASH PLATE COMPRESSOR

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CPC

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