JP2016169717A - Variable capacity type swash plate compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor capable of keeping an inclination angle at a minimum state even if the number of revolution of a driving shaft is increased under a state in which the inclination angle of a swash plate is in its minimum state.SOLUTION: A compressor of this invention comprises a cylinder block 21, a driving shaft 3, a swash plate 5, a link mechanism 7, a piston 9, a rear housing 19, a valve plate 23 and a discharging valve 43a. The valve plate 23 forms each compression chamber 57 together with each cylinder bore 21a of the cylinder block 21 and each piston 9. Each compression chamber 57 has second compression chambers 57b1, 57b2 and 57b3 where a dead volume DV2 larger than a dead volume DV1 of the first compression chambers 57a1, 57a2 and 57a3. If the number of revolution of the driving shaft 3 becomes more than a prescribed value R1 under a state in which the inclination angle of the swash plate 5 is kept minimum, the discharging valve 43a keeps the closed state of the second compression chambers 57b1, 57b2 and 57b3.SELECTED DRAWING: Figure 6

Description

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

  Patent Document 1 discloses a conventional variable displacement swash plate compressor (hereinafter referred to as a compressor). This compressor includes a cylinder block, a drive shaft, a swash plate, and a link mechanism. A swash plate chamber and a plurality of cylinder bores are formed in the cylinder block. The drive shaft is rotatably supported by the cylinder block. The swash plate is disposed in the swash plate chamber and is rotated together with the drive shaft. The link mechanism is provided between the drive shaft and the swash plate. The link mechanism allows a change in the inclination angle of the swash plate with respect to the direction orthogonal to the rotational axis of the drive shaft.

  The compressor includes a plurality of pistons, a rear housing as a head member, a front housing, a valve plate, a plurality of discharge valves, and a control mechanism. Each piston is housed in a cylinder bore. Each piston reciprocates at a stroke corresponding to the inclination angle of the swash plate by rotation of the swash plate to form a compression chamber in each cylinder bore. The rear housing is joined to the cylinder block and forms a discharge chamber on the compression chamber side. The front housing forms a swash plate chamber together with the cylinder block. The valve plate is provided between the cylinder block and the rear housing. The valve plate forms each compression chamber together with each cylinder bore and each piston. Each discharge valve is provided on a valve plate. Each discharge valve opens and closes each compression chamber and the discharge chamber by a differential pressure between each compression chamber and the discharge chamber. The control mechanism appropriately supplies high-pressure refrigerant in the discharge chamber to the swash plate chamber, and controls the pressure in the swash plate chamber.

  In this compressor, when the differential pressure between the pressure in the swash plate chamber and the suction pressure via each piston is increased by the control mechanism, the swash plate is tilted so that the tilt angle is decreased. As a result, the discharge capacity of the compressor is reduced. On the other hand, in this compressor, when the pressure difference between the pressure in the swash plate chamber and the suction pressure through each piston is reduced by the control mechanism, the swash plate is tilted so that the inclination angle is increased. As a result, the discharge capacity of the compressor increases.

  This compressor is used without a clutch in which a driving force is always transmitted to the drive shaft, and is in an OFF operation state with a minimum capacity when the inclination angle of the swash plate is minimum. Here, since the discharge capacity per one rotation of the drive shaft does not become zero even in the OFF operation state, the discharge flow rate at which the refrigerant is discharged from each compression chamber to the discharge chamber increases in proportion to the rotation speed of the drive shaft. (Discharge flow rate per unit time = discharge capacity per one rotation of the drive shaft × number of rotations per unit time of the drive shaft). Along with this, the restoring force for increasing the inclination angle of the swash plate from the minimum increases. In this respect, in this compressor, by utilizing the swash plate chamber having a large volume for changing the tilt angle of the swash plate, the tilt angle of the swash plate can be maintained at a minimum state against the restoring force.

  Although not specified in Patent Document 1, in such a conventional compressor, the dead volumes of all the compression chambers are generally set equal.

Japanese Patent Laid-Open No. 7-127666

  By the way, unlike the conventional compressor described above, an actuator comprising a partition body, a moving body and a control pressure chamber is provided in the swash plate chamber, and the actuator is controlled by a control mechanism to change the inclination angle of the swash plate. There is a machine. In this compressor, the partition body is provided so as to be integrally rotatable with the drive shaft in the swash plate chamber. The moving body is provided in the swash plate chamber and can rotate integrally with the drive shaft, and moves in the direction of the rotation axis with respect to the partition body to change the inclination angle of the swash plate. The control pressure chamber is partitioned by a partition body and a moving body. The control pressure chamber moves the moving body so as to decrease the inclination angle of the swash plate as the internal pressure increases. The control mechanism controls the pressure in the control pressure chamber.

  In this compressor, the pressing force of the moving body against the swash plate is restricted by the control pressure chamber having a smaller volume than the swash plate chamber. For this reason, in this compressor, if the return force acting on the swash plate increases as the rotational speed of the drive shaft increases with the inclination angle of the swash plate being at a minimum, the pressing force resists the return force. There is a risk that it becomes difficult to maintain the inclination angle of the swash plate at a minimum state.

  The present invention has been made in view of the above-described conventional situation, and maintains a minimum inclination angle even when the number of rotations of the drive shaft increases in a state where the inclination angle of the swash plate is minimum. It is an issue to be solved to provide a compressor capable of achieving this.

The compressor of the present invention includes a cylinder block in which a swash plate chamber and a plurality of cylinder bores are formed,
A drive shaft rotatably supported by the cylinder block;
A swash plate disposed in the swash plate chamber and rotated together with the drive shaft;
A link mechanism provided between the drive shaft and the swash plate, and allowing a change in the inclination angle of the swash plate with respect to a direction orthogonal to the rotational axis of the drive shaft;
A piston that is housed in each cylinder bore and reciprocates at a stroke according to the tilt angle by rotation of the swash plate to form a compression chamber in each cylinder bore;
A head member joined to the cylinder block and forming a discharge chamber on the compression chamber side;
A valve plate which is provided between the cylinder block and the head member and forms the compression chambers together with the cylinder bores and the pistons;
A discharge valve provided on the valve plate for opening and closing each compression chamber and the discharge chamber by a differential pressure between each compression chamber and the discharge chamber;
A partition provided in the swash plate chamber so as to be integrally rotatable with the drive shaft;
A movable body provided in the swash plate chamber and capable of rotating integrally with the drive shaft and moving in the rotational axis direction relative to the partition body to change the tilt angle;
A control pressure chamber that is partitioned by the partition body and the moving body, and moves the moving body so as to decrease the inclination angle by increasing an internal pressure;
A control mechanism for controlling the pressure in the control pressure chamber,
Each compression chamber has a first compression chamber and a second compression chamber in which a dead volume larger than the dead volume of the first compression chamber is set,
The discharge valve maintains the second compression chamber closed when the rotational speed of the drive shaft is equal to or greater than a predetermined value in a state where the inclination angle is minimum.

  In the compressor according to the present invention, the discharge flow rate at which the refrigerant is discharged from the compression chambers to the discharge chambers is increased by increasing the rotational speed of the drive shaft in a state where the inclination angle of the swash plate is minimum. At this time, if the rotational speed of the drive shaft is less than a predetermined value, the discharge valve opens and closes each compression chamber and the discharge chamber by a differential pressure between each compression chamber and the discharge chamber. For this reason, the discharge flow rate increases at a predetermined increase rate in proportion to the rotational speed of the drive shaft. And if the rotation speed of a drive shaft becomes more than predetermined value, a discharge valve will maintain closure of a 2nd compression chamber. For this reason, the increase rate of the discharge flow rate is reduced by the amount corresponding to the closing of the second compression chamber. As a result, in this compressor, an increase in the restoring force acting on the swash plate can be suppressed. For this reason, in this compressor, even if the pressing force acting on the swash plate of the moving body is restricted by the control pressure chamber having a smaller volume than the swash plate chamber, the pressing force can resist the restoring force. .

  Therefore, in the compressor of the present invention, even when the rotational speed of the drive shaft is increased in the state where the inclination angle of the swash plate is minimum, the inclination angle can be maintained at the minimum state. In particular, when this compressor is used without a clutch, the OFF operation state can be suitably maintained.

  It is desirable that four or more cylinder bores be formed around the rotation axis. It is desirable that two or more second compression chambers are provided so as not to be adjacent to each other. In this case, the second compression chamber having a large dead volume is arranged without any deviation. For this reason, when the rotation angle of the drive shaft becomes a predetermined value or more with the inclination angle being the minimum, and the discharge valve maintains the second compression chamber closed, it is possible to suppress the bias of the refrigerant discharged to the discharge chamber.

  It is desirable that two or more second compression chambers have different dead volumes. And as for each discharge valve, it is desirable to maintain closure of each 2nd compression chamber in steps as the number of rotations of a drive shaft increases. In this case, an increase in the return force accompanying an increase in the rotational speed of the drive shaft can be more finely suppressed.

  It is desirable that the second compression chamber has a dead volume larger than that of the first compression chamber by a first groove recessed in the top surface of the piston.

  It is desirable that the second compression chamber has a dead volume larger than that of the first compression chamber by a second groove recessed in the compression chamber side surface of the valve plate.

  It is desirable that the second compression chamber has a dead volume larger than that of the first compression chamber by a third groove formed in the inner peripheral surface of the cylinder bore.

  In these cases, it is possible to easily realize a configuration in which the second compression chamber is set to have a larger dead volume than the first compression chamber.

  The compressor of the present invention can maintain the inclination angle in the minimum state even when the rotational speed of the drive shaft increases in the state where the inclination angle of the swash plate is minimum.

FIG. 1 is a longitudinal sectional view of a variable displacement swash plate compressor according to the first embodiment in a state where the inclination angle is maximum. FIG. 2 is a longitudinal sectional view of the variable displacement swash plate compressor according to the first embodiment in a state where the inclination angle is minimum. FIG. 3 is a schematic diagram illustrating a control mechanism according to the first embodiment. FIG. 4 is a plan view illustrating a relative positional relationship among a cylinder bore, a compression chamber, a valve plate, a discharge valve, and the like according to the first embodiment. FIG. 5 is an essential part enlarged cross-sectional view illustrating a dead volume of a second compression chamber according to the first embodiment. FIG. 6 is a graph illustrating the relationship between the rotational speed of the drive shaft and the return force acting on the swash plate according to the first embodiment. FIG. 7 is a graph showing the relationship between the rotational speed of the drive shaft and the return force acting on the swash plate according to the second embodiment. FIG. 8 is an essential part enlarged cross-sectional view illustrating a dead volume of the second compression chamber according to the third embodiment. FIG. 9 is an enlarged cross-sectional view of a main part illustrating a dead volume of the second compression chamber according to the fourth embodiment.

  Embodiments 1 to 4 embodying the present invention will be described below with reference to the drawings.

Example 1
As shown in FIG.1 and FIG.2, the compressor of Example 1 is an example of the specific aspect of the capacity | capacitance variable swash plate type compressor of this invention, and employ | adopts the single-headed piston. This compressor is mounted on a vehicle and constitutes a refrigeration circuit of a vehicle air conditioner. 1 and 2, the direction in which the rotation axis O of the drive shaft 3 extends is the front-rear direction of the compressor. 1 and 2, the left side of the drawing is the front of the compressor, and the right side of the drawing is the rear of the compressor.

  As shown in FIGS. 1 and 2, the compressor includes a housing 1, a drive shaft 3, a swash plate 5, a link mechanism 7, a plurality of pistons 9, a valve plate 23, and an actuator 13. Moreover, this compressor is provided with the control mechanism 15 as shown in FIG.

  As shown in FIGS. 1 and 2, the housing 1 includes a front housing 17, a cylinder block 21, and a rear housing 19. The front housing 17 is joined to the cylinder block 21 from the front side of the compressor. The rear housing 19 is joined to the cylinder block 21 from the rear side of the compressor. The rear housing 19 is an example of the “head member” in the present invention. The valve plate 23 is provided between the rear housing 19 and the cylinder block 21.

  The front housing 17 has a front wall 17a and a peripheral wall 17b. The front wall 17a is located on the front side of the compressor and extends in a substantially disc shape in a direction orthogonal to the rotation axis O. The peripheral wall 17b is connected to the outer peripheral edge of the front wall 17a and extends in a substantially cylindrical shape from the front to the rear of the compressor. The front housing 17 has a bottomed substantially cylindrical shape by a front wall 17a and a peripheral wall 17b.

  A boss 17c that protrudes forward is formed on the front wall 17a. A shaft seal device 27 is provided in the boss 17c. Further, a first shaft hole 17d extending in the front-rear direction of the compressor is formed in the boss 17c. A first sliding bearing 29a is provided in the first shaft hole 17d.

  A part of the control mechanism 15 is provided in the rear housing 19. The rear housing 19 is formed with a first pressure adjustment chamber 31a, a suction chamber 33, and a discharge chamber 35. The first pressure adjustment chamber 31 a is located at the center portion of the rear housing 19. The suction chamber 33 has an annular shape surrounding the first pressure adjustment chamber 31 a in the rear housing 19. The discharge chamber 35 is located on the outer peripheral side of the rear housing 19 and on the compression chamber 57 side described later, and has an annular shape surrounding the suction chamber 33. The discharge chamber 35 is connected to a discharge port (not shown).

  In the cylinder block 21, the same number of cylinder bores 21a as the pistons 9 are formed at equal angular intervals in the circumferential direction. In the present embodiment, there are six pistons 9, and as shown in FIG. 4, six cylinder bores 21 a are arranged around the rotation axis O at equal intervals in the cylinder block 21. As shown in FIGS. 1 and 2, a swash plate chamber 25 is formed by the front end face of the cylinder block 21 and the front wall 17 a and the peripheral wall 17 b of the front housing 17. A suction port 250 communicating with the swash plate chamber 25 is formed in the peripheral wall 17 b of the front housing 17.

  The cylinder block 21 has a second shaft hole 21c and a spring chamber 21d. The second shaft hole 21 c extends from the front end surface side of the cylinder block 21 to the rear of the compressor, and the rear end side penetrates the cylinder block 21. A second sliding bearing 29b is provided in the second shaft hole 21c. The spring chamber 21d is located between the swash plate chamber 25 and the second shaft hole 21c. A return spring 37 is disposed in the spring chamber 21d. The return spring 37 urges the swash plate 5 having the smallest inclination angle toward the front of the swash plate chamber 25.

  A suction passage 39 is formed in the cylinder block 21. The suction passage 39 is located between the second shaft hole 21c and the cylinder bore 21a and extends in the front-rear direction. The front end side of the suction passage 39 opens to the front end surface of the cylinder block 21 and communicates with the swash plate chamber 25. The rear end side of the suction passage 39 is open to the rear end surface of the cylinder block 21.

  The valve plate 23 includes a valve plate body 40, a suction valve plate 41, a discharge valve plate 43, and a retainer plate 45.

  The valve plate main body 40, the discharge valve plate 43, and the retainer plate 45 are formed with the same number of intake ports 40a as the cylinder bores 21a. The valve plate body 40 and the intake valve plate 41 are formed with the same number of discharge ports 40b as the cylinder bores 21a. Each cylinder bore 21a communicates with the suction chamber 33 through each suction port 40a and also communicates with the discharge chamber 35 through each discharge port 40b.

  The suction valve plate 41 is provided on the front surface of the valve plate body 40. The intake valve plate 41 is formed with a plurality of intake valves 41a that can open and close each intake port 40a by elastic deformation. The discharge valve plate 43 is provided on the rear surface of the valve plate body 40. The discharge valve plate 43 is formed with a plurality of discharge valves 43a capable of opening and closing each discharge port 40b by elastic deformation. The retainer plate 45 is provided on the rear surface of the discharge valve plate 43. The retainer plate 45 regulates the maximum opening of the discharge valve 43a. In this embodiment, as shown in FIG. 4, six discharge ports 40b and six discharge valves 43a are provided at positions corresponding to the six cylinder bores 21a.

  As shown in FIGS. 1 and 2, the drive shaft 3 is inserted from the boss 17 c side to the cylinder block 21. The drive shaft 3 is inserted through the shaft seal device 27 in the boss 17c. The front end side of the drive shaft 3 is pivotally supported in the first shaft hole 17d of the front jing 17 by a first sliding bearing 29a. The rear end side of the drive shaft 3 is pivotally supported by a second sliding bearing 29 b in the second shaft hole 21 c of the cylinder block 21. Thus, the drive shaft 3 is supported by the housing 1 so as to be rotatable around the rotation axis O. A second pressure adjustment chamber 31b is defined between the rear end of the drive shaft 3 in the second shaft hole 21c.

  The valve plate 40, the suction valve plate 41, the discharge valve plate 43, and the retainer plate 45 are formed with a first communication hole 41c and a second communication hole 40d.

  The first pressure adjustment chamber 31a of the rear housing 19 communicates with the second pressure adjustment chamber 31b of the cylinder block 21 through the first communication hole 41c. A pressure regulation chamber 31 is formed by the first pressure regulation chamber 31a and the second pressure regulation chamber 31b. The pressure adjustment chamber 31 is sealed by O-rings 49a and 49b provided on the rear end side of the drive shaft 3, and the swash plate chamber 25 and the pressure adjustment chamber 31 are not in communication. The rear end side of the suction passage 39 communicates with the suction chamber 33 through the second communication hole 40d.

  A link mechanism 7, a swash plate 5, and an actuator 13 are attached to the drive shaft 3.

  The link mechanism 7 is provided between the drive shaft 3 and the swash plate 5. The link mechanism 7 includes a lug plate 51, a pair of drive arms 53 a and 53 a formed on the lug plate 51, and a pair of swash plate arms 5 e and 5 e formed on the swash plate 5. 1 and 2, only one of the drive arms 53a and 53a and the swash plate arms 5e and 5e is shown. Although not shown, the other of the drive arms 53a and 53a and the swash plate arms 5e and 5e is located on the front side of the paper surface in FIGS.

  The lug plate 51 is provided with an insertion hole 51h in the center, and has a substantially annular shape as a whole. The lug plate 51 has the drive shaft 3 press-fitted into the insertion hole 51h, and can rotate integrally with the drive shaft 3. The lug plate 51 is located on the front end side in the swash plate chamber 25, and is disposed in front of the swash plate 5 in a state of facing the swash plate 5. A thrust bearing 55 is provided between the lug plate 51 and the front wall 17a.

  A cylindrical cylinder chamber 51 a is recessed in the lug plate 51. The cylinder chamber 51 a is recessed from the rear end surface of the lug plate 51 on the swash plate 5 side in the lug plate 51 so as to cover the insertion hole 51 h, and to the location inside the thrust bearing 55 in the lug plate 51. It extends. The cylinder chamber 51 a is formed concentrically with the insertion hole 51 h and is located at the center of the lug plate 51.

  The drive arms 53 a and 53 a extend rearward from the rear surface side of the lug plate 51. The lug plate 51 is formed with a guide surface 54a at a position between the drive arms 53a and 53a. The guide surface 54 a is formed so as to incline from the front to the rear as it goes in the radially inward direction of the lug plate 51.

  The swash plate 5 has an annular flat plate shape and has a front surface 5a and a rear surface 5b. A weight portion 5c is formed on the front surface 5a. The weight portion 5c protrudes in a substantially cylindrical shape from the front surface 5a side of the swash plate 5 toward the front. The weight part 5 c comes into contact with the lug plate 51 at the front end face 50 when the inclination angle of the swash plate 5 becomes maximum. An insertion hole 5 d is formed at the center of the swash plate 5. The drive shaft 3 is inserted through the insertion hole 5d.

  The swash plate arms 5e and 5e extend forward from the front surface 5a of the swash plate 5. A guided surface 52g is formed on the tip side of the swash plate arms 5e and 5e.

  On the front surface 5a side of the swash plate 5, a convex portion 5g is formed. The convex portion 5g is located between the swash plate arms 5e and 5e and protrudes forward in a substantially hemispherical shape.

  The swash plate 5 is assembled to the drive shaft 3 with the swash plate arms 5e and 5e being sandwiched between the drive arms 53a and 53a. Thereby, the rotation of the drive shaft 3 is transmitted from the drive arms 53 a and 53 a to the swash plate arms 5 e and 5 e, so that the swash plate 5 can rotate in the swash plate chamber 25 together with the lug plate 51.

  The guided surfaces 52g of the swash plate arms 5e and 5e are in contact with the guide surface 54a. The link mechanism 7 allows the inclination angle of the swash plate 5 to be changed with respect to the direction orthogonal to the rotational axis O of the drive shaft 3 by sliding the guided surface 52g on the guide surface 54a. The inclination angle of the swash plate 5 can be changed from the maximum state shown in FIG. 1 to the minimum state shown in FIG. 2 while substantially maintaining the top dead center position T.

  As shown in FIGS. 1 and 2, the actuator 13 includes a lug plate 51, a moving body 13a, and a control pressure chamber 13b. The lug plate 51 in which the cylinder chamber 51a is recessed is an example of the “partition body” of the present invention.

  The moving body 13a is inserted through the drive shaft 3 so as to be integrally rotatable. The moving body 13a is movable in the direction of the rotational axis O while being in sliding contact with the drive shaft 3. The moving body 13 a has a cylindrical shape that is coaxial with the drive shaft 3, and has a smaller diameter than the thrust bearing 55. The moving body 13a has a shape in which the diameter gradually increases from the rear side toward the front side.

  An action portion 13p is integrally formed on the rear end side of the moving body 13a. The action part 13p protrudes from the rotation axis O side toward the top dead center position T side of the swash plate 5, and is in contact with the convex part 5g. The front end side of the moving body 13 a is fitted into the cylinder chamber 51 a of the lug plate 51. In a state where the moving body 13a has entered most into the cylinder chamber 51a, the front end of the moving body 13 reaches the inside of the thrust bearing 55 in the cylinder chamber 51a.

  The control pressure chamber 13b is partitioned by the front end side of the moving body 13a, the cylinder chamber 51a, and the drive shaft 3. The control pressure chamber 13b is sealed by O-rings 49c and 49d provided on the inner peripheral side and the outer peripheral side of the movable body 13a, respectively, and is not in communication with the swash plate chamber 25.

  In the drive shaft 3, an axial path 3a and a radial path 3b are formed. The rear end of the axial path 3a is open to the second pressure adjustment chamber 31b. The axial path 3a is centered on the rotation axis O and extends from the rear end of the drive shaft 3 toward the front end side. The radial path 3b extends radially outward from the front end of the axial path 3a, opens on the outer peripheral surface of the drive shaft 3, and communicates with the control pressure chamber 13b.

  At the front end of the drive shaft 3, there is formed a screw portion 3e for connection to a pulley, an electromagnetic clutch or the like (not shown). In this embodiment, although not shown, a pulley is connected to the front end of the drive shaft 3 and is connected to the engine of the vehicle via a pulley belt. That is, the compressor according to the present embodiment is used without a clutch in which a driving force is always transmitted from the running engine to the drive shaft 3.

  Each piston 9 is housed in each cylinder bore 21a, and can reciprocate in each cylinder bore 21a. Each piston 9 and valve plate 23 form a compression chamber 57 in each cylinder bore 21a.

  In this embodiment, there are six pistons 9 and six cylinder bores 21a as shown in FIG. 4, so six compression chambers 57 are formed. For each compression chamber 57, the one located on the uppermost side in FIG. 4 is referred to as a compression chamber 57a1, and the compression chamber 57b1, the compression chamber 57a2, the compression chamber 57b2, and the compression chamber are arranged in the clockwise order from the compression chamber 57a1. 57a3 and compression chamber 57b3.

  As shown in FIGS. 1 and 2, each piston 9 is provided with an engaging portion 9a. In the engaging portion 9a, hemispherical shoes 11a and 11b are respectively provided. The shoes 11 a and 11 b convert the rotation of the swash plate 5 into the reciprocating motion of each piston 9. Each piston 9 can reciprocate in the cylinder bore 21 a by a stroke corresponding to the inclination angle of the swash plate 5 by the rotation of the swash plate 5.

  As shown in FIG. 3, the control mechanism 15 includes a low pressure passage 15a, a control valve 15c, a high pressure passage 15b, an orifice 15d, an axial passage 3a, and a radial passage 3b.

  The pressure regulation chamber 31 and the suction chamber 33 communicate with each other through the low pressure passage 15a. The control valve 15c is provided in the low pressure passage 15a. The control valve 15c adjusts the opening of the low pressure passage 15a based on the pressure in the suction chamber 33. The pressure adjusting chamber 31 and the discharge chamber 35 are communicated with each other by the high-pressure passage 15b. The orifice 15d is provided in the high-pressure passage 15b. The pressure adjusting chamber 31 and the control pressure chamber 13b communicate with each other by the axial path 3a and the radial path 3b.

  In this compressor, piping connected to the evaporator is connected to the suction port 250 shown in FIGS. 1 and 2. Moreover, piping connected to a condenser is connected with respect to the discharge outlet connected with the discharge chamber 35 shown in FIG.1 and FIG.2. The condenser is connected to the evaporator via a pipe and an expansion valve. A compressor, an evaporator, an expansion valve, a condenser, and the like constitute a refrigeration circuit for a vehicle air conditioner. In addition, illustration of an evaporator, an expansion valve, a condenser, and each piping is abbreviate | omitted.

  In the compressor configured as described above, when the drive shaft 3 rotates, the swash plate 5 rotates and each piston 9 reciprocates in each cylinder bore 21a. For this reason, the compression chamber 57 changes the volume according to the piston stroke. Therefore, the refrigerant sucked into the swash plate chamber 25 from the evaporator through the suction port 250 is compressed in the compression chamber 57 from the suction passage 39 through the suction chamber 33. Each discharge valve 43 a opens and closes each compression chamber 57 and the discharge chamber 35 by a differential pressure between each compression chamber 57 and the discharge chamber 35. Thus, the refrigerant compressed in each compression chamber 57 is discharged into the discharge chamber 35 and discharged from the discharge port to the condenser.

  In this compressor, the discharge capacity can be changed by changing the inclination angle of the swash plate 5 by the actuator 13 and increasing / decreasing the stroke of the piston 9 as described below.

  First, the case where the inclination angle of the swash plate 5 changes to the maximum state shown in FIG. 1 will be described. In the control mechanism 15 shown in FIG. 3, if the control valve 15c increases the opening of the low-pressure passage 15a, the pressure in the pressure adjustment chamber 31 and thus the pressure in the control pressure chamber 13c are almost equal to the pressure in the suction chamber 33. Become. Therefore, as shown in FIG. 1, in the actuator 13, the volume of the control pressure chamber 13b is reduced by the reaction force from each piston 9 etc. acting on the swash plate 5, and the moving body 13a is inclined in the direction of the rotation axis O. It moves from the plate 5 side toward the lug plate 51 side. Then, the moving body 13a enters deeply into the cylinder chamber 51a.

  At the same time, the swash plate arms 5e and 5e are guided by the reaction force acting on the swash plate 5 and the urging force of the return spring 37 so that the swash plate arms 5e and 5e are remote from the rotation axis O in the radially outward direction. The surface 52g slides on the guide surface 54a of the lug plate 51.

  For this reason, the swash plate 5 is in a state in which the inclination angle increases while substantially maintaining the top dead center position T, and the inclination angle shown in FIG. 1 is maximum. Thereby, in this compressor, the stroke of piston 9 becomes the maximum, and the discharge capacity per one rotation of drive shaft 3 becomes the maximum capacity.

  Next, the case where the inclination angle of the swash plate 5 decreases from the maximum state shown in FIG. 1 and changes to the minimum state shown in FIG. 2 will be described. In the control mechanism 15 shown in FIG. 3, if the control valve 15c reduces the opening of the low-pressure passage 15a, the pressure in the pressure adjustment chamber 31 and thus the pressure in the control pressure chamber 13b are larger than the pressure in the suction chamber 33. Become. For this reason, as shown in FIG. 2, in the actuator 13, the volume of the control pressure chamber 13 b increases against the reaction force from each piston 9 acting on the swash plate 5, and the moving body 13 a is moved from the lug plate 51. It moves in the direction of the rotation axis O toward the swash plate 5 side while being remote.

  Thereby, in the actuator 13, the action portion 13 p presses the convex portion 5 g toward the rear of the swash plate chamber 25. Therefore, the guided surface 52g of the swash plate arms 5e, 5e slides on the guide surface 54a of the lug plate 51 so that the swash plate arms 5e, 5e are close to the rotation axis O.

  For this reason, the swash plate 5 is kept in the top dead center position T, the inclination angle becomes small and comes into contact with the return spring 37, and the inclination angle shown in FIG. Thereby, in this compressor, the stroke of piston 9 becomes the minimum and the discharge capacity per one rotation of drive shaft 3 becomes the minimum capacity.

  Since this compressor is used without a clutch in which the driving force is always transmitted from the running engine to the drive shaft 3, the compressor is in the OFF operation state with the minimum capacity in the state where the inclination angle shown in FIG. Become. Even in the OFF operation state, the rotational speed of the drive shaft 3 increases or decreases according to a change in the rotational speed of the engine.

  Here, in this compressor, since the inclination angle is changed while the swash plate 5 substantially maintains the top dead center position T, as shown in FIGS. 1 and 2, the top dead center position T of the swash plate 5 is changed. The volume of each compression chamber 57 when the piston 9 is closest to the valve plate 23, that is, the dead volume DV of each compression chamber 57 is substantially constant regardless of the increase or decrease in the inclination angle of the swash plate 5. . In this embodiment, the dead volume DV of each compression chamber 57 is set as described below.

  As shown in FIG. 4, among the six compression chambers 57, the compression chamber 57a1, the compression chamber 57a2, and the compression chamber 57a3 are the first compression chambers. On the other hand, among the six compression chambers 57, the compression chamber 57b1, the compression chamber 57b2, and the compression chamber 57b3 are second compression chambers.

  The second compression chamber 57b1 is disposed between the first compression chamber 57a1 and the first compression chamber 57a2. The second compression chamber 57b2 is disposed between the first compression chamber 57a2 and the first compression chamber 57a3. The second compression chamber 57b3 is disposed between the first compression chamber 57a3 and the first compression chamber 57a1. That is, the second compression chambers 57b1, 57b2, and 57b3 are provided so as not to be adjacent to each other.

  The dead volumes DV of the first compression chambers 57a1, 57a2, 57a3 are set equal to each other. The dead volume DV of each first compression chamber 57a1, 57a2, 57a3 is defined as DV1. The dead volumes DV of the second compression chambers 57b1, 57b2, 57b3 are also set equal to each other. The dead volume DV of each second compression chamber 57b1, 57b2, 57b3 is set to DV2.

  The dead volume DV1 of each of the first compression chambers 57a1, 57a2, 57a3 is set in the same manner as the existing compressor. Specifically, the dead volume DV1 of each of the first compression chambers 57a1, 57a2, and 57a3 corresponds to each of the first compression chambers 5 when the rotational speed of the drive shaft 3 increases with the inclination angle of the swash plate 5 being the minimum shown in FIG. Each discharge valve 43a corresponding to the chambers 57a1, 57a2, 57a3 is set so as to continuously open and close the first compression chambers 57a1, 57a2, 57a3 and the discharge chamber 35.

  On the other hand, as shown in FIG. 5, the dead volume DV2 of each of the second compression chambers 57b1, 57b2, and 57b3 is set larger than the dead volume DV1 of each of the first compression chambers 57a1, 57a2, and 57a3. Specifically, as shown in FIG. 5, the first groove 9b is recessed in the top surface 9a of the piston 9 forming the second compression chambers 57b1, 57b2, and 57b3. By appropriately setting the shape, depth, etc. of the first groove 9b, the dead volume DV2 of each of the second compression chambers 57b1, 57b2, 57b3 is equal to the volume of the first groove 9b. , 57a2 and 57a3 are larger than the dead volume DV1.

  In the present embodiment, the dead volume DV2 of each of the second compression chambers 57b1, 57b2, and 57b3 is a predetermined value R1 in which the rotation angle of the drive shaft 3 is the minimum value shown in FIG. If it becomes above, the differential pressure | voltage between each 2nd compression chamber 57b1, 57b2, 57b3 and the discharge chamber 35 will become small, and each discharge valve 43a corresponding to each 2nd compression chamber 57b1, 57b2, 57b3 will carry out each 2nd compression. The first compression chambers 57a1, 57a2, and 57a3 are set to have a large dead volume DV1 so as to keep the chambers 57b1, 57b2, and 57b3 closed. The predetermined value R1 is appropriately set based on an evaluation result such as a compressor performance experiment.

  Here, while comparing the effects of the difference between the dead volume DV1 of each of the first compression chambers 57a1, 57a2, and 57a3 and the dead volume DV2 of the second compression chambers 57b1, 57b2, and 57b3 with the comparative example 1 and the comparative example 2. explain. A solid line J1 shown in FIG. 6 corresponds to the first embodiment. A one-dot chain line straight line L <b> 1 shown in FIG. 6 corresponds to the first comparative example. A two-dot chain line L2 illustrated in FIG. 6 corresponds to the second comparative example.

  In the first comparative example, for the six compression chambers 57 according to the compressor of the first embodiment, the first compression chambers 57a1, 57a2, 57a3 and the second compression chambers 57b1, 57b2, 57b3 are all distinguished from each other. The dead volume DV of the compression chamber 57 is changed to DV1. That is, in Comparative Example 1, the dead volumes DV (= DV1) of all the compression chambers 57 are set in the same manner as the existing compressor. Other configurations of Comparative Example 1 are the same as those of Example 1.

  As shown by the straight line L1 in FIG. 6, when the rotation speed of the drive shaft 3 increases with the inclination angle of the swash plate 5 being the minimum shown in FIG. 2, each discharge valve 43a causes the compression chamber 57 and the discharge chamber 35 to move. Open and close continuously. For this reason, the discharge flow rate at which the refrigerant is discharged from each compression chamber 57 into the discharge chamber 35 increases in proportion to the rotational speed of the drive shaft 3. Along with this, the restoring force for increasing the inclination angle of the swash plate 5 from the minimum increases proportionally.

  Here, the pressing force of the movable body 13 a against the swash plate 5 is restricted by the control pressure chamber 13 b having a smaller volume than the swash plate chamber 25. For this reason, in Comparative Example 1, when the return force acting on the swash plate 5 increases as the rotational speed of the drive shaft 3 increases in the OFF operation state, the pressing force of the moving body 13a against the swash plate 5 resists the return force. May not be able to be performed, and as a result, it may be difficult to maintain the inclination angle of the swash plate 5 in a minimum state.

  In Comparative Example 2, for the six compression chambers 57 according to the compressor of Example 1, the first compression chambers 57a1, 57a2, 57a3 and the second compression chambers 57b1, 57b2, 57b3 are all distinguished, and all The dead volume DV of the compression chamber 57 is changed to DV2. That is, in Comparative Example 2, the dead volume DV (= DV2) of all the compression chambers 57 is set larger than the dead volume DV (= DV1) of all the compression chambers 57 in Comparative Example 1. Other configurations of Comparative Example 2 are the same as those of Example 1.

  In Comparative Example 2, as shown by the straight line L2 in FIG. 6, when the rotational speed of the drive shaft 3 increases with the inclination angle of the swash plate 5 being the minimum shown in FIG. 2, each discharge valve 43a is connected to each compression chamber 57. The return force acting on the swash plate 5 increases proportionally by opening and closing the discharge chamber 35. At this time, corresponding to the fact that the dead volumes DV = DV2> DV1 of all the compression chambers 57, the restoring force acting on the swash plate 5 is a value smaller than that of the comparative example 1 and is the same as that of the comparative example 1. It increases with the slope of. As a result, in Comparative Example 2, when the rotational speed of the drive shaft 3 is in the low speed range in the OFF operation state, there is a possibility that the restoring force acting on the swash plate 5 may be insufficient.

  On the other hand, in the compressor of the first embodiment, as indicated by the solid line J1 in FIG. 6, the rotational speed of the drive shaft 3 is less than the predetermined value R1 with the inclination angle of the swash plate 5 being the minimum state shown in FIG. When increased in the range, each discharge valve 43a opens and closes each first compression chamber 57a1, 57a2, 57a3 and each second compression chamber 57b1, 57b2, 57a3) and the discharge chamber 35. At this time, the restoring force acting on the swash plate 5 is smaller than that of the first comparative example and smaller than that of the second comparative example, corresponding to the fact that the dead volumes DV2> DV1 of the second compression chambers 57b1, 57b2, 57b3. It increases at a large value and with the same inclination as in Comparative Examples 1 and 2. As a result, in this compressor, even when the rotational speed of the drive shaft 3 is in the low speed range in the OFF operation state, the return force acting on the swash plate 5 is unlikely to be insufficient.

  Further, in this compressor, as shown by a solid line J1 in FIG. 6, each second rotation is performed if the rotation angle of the drive shaft 3 is equal to or greater than a predetermined value R1 with the inclination angle of the swash plate 5 in the minimum state shown in FIG. Corresponding to dead volume DV2> DV1 of compression chambers 57b1, 57b2, 57b3, each discharge valve 43a corresponding to each first compression chamber 57a1, 57a2, 57a3 is connected to each first compression chamber 57a1, 57a2, 57a3. While the discharge chamber 35 is continuously opened and closed, the discharge valves 43a corresponding to the second compression chambers 57b1, 57b2, and 57b3 maintain the second compression chambers 57b1, 57b2, and 57b3 closed. For this reason, the increase rate of the discharge flow rate is reduced by the amount of closing of the second compression chambers 57b1, 57b2, and 57b3, and the slope of the solid line J1 is reduced. As a result, in this compressor, an increase in the restoring force acting on the swash plate 5 can be suppressed. Therefore, in this compressor, even if the pressing force acting on the swash plate 5 of the moving body 13a is restricted by the control pressure chamber 13b having a smaller volume than the swash plate chamber 25, the pressing force resists the restoring force. can do.

  Therefore, in the compressor of the first embodiment, in the state where the inclination angle of the swash plate 5 is the minimum, that is, in the OFF operation state, the inclination angle can be maintained at the minimum state even if the rotation speed of the drive shaft 3 increases. it can.

  Further, in this compressor, as shown in FIG. 4, the second compression chambers 57b1, 57b2, 57b3 satisfying dead volume DV = DV2> DV1 are provided so as not to be adjacent to each other, and around the rotation axis O. Arranged without bias. For this reason, when each discharge valve 43a maintains each 2nd compression chamber 57b1, 57b2, 57b3 closed, the bias | inclination of the refrigerant | coolant discharged to the discharge chamber 35 can be suppressed.

(Example 2)
In the compressor of the second embodiment, the dead volume DV of the second compression chamber 57b1 is DV2 while the dead volume DV2 of the second compression chamber 57b2 is changed to DV3> DV2, and the dead volume DV of the second compression chamber 57b3 is set to be equal to DV2. DV4>DV3> DV2. Other configurations of the second embodiment are the same as those of the first embodiment.

  A solid line J2 illustrated in FIG. 7 corresponds to the second embodiment. A dashed-dotted straight line L1 shown in FIG. 7 is the same as the straight line L1 shown in FIG. A two-dot chain line L2 shown in FIG. 7 is the same as the straight line L2 shown in FIG.

  As described above, the dead volume DV2 of the second compression chamber 57b1 is as long as the rotation angle of the drive shaft 3 is not less than the predetermined value R1 shown in FIG. The pressure difference between the second compression chamber 57b1 and the discharge chamber 35 is reduced, and the discharge valve 43a corresponding to the second compression chamber 57b1 is set to keep the second compression chamber 57b1 closed.

  The dead volume DV3 of the second compression chamber 57b2 is the second compression chamber 57b2 when the rotation angle of the drive shaft 3 is equal to or greater than the predetermined value R2 shown in FIG. The discharge valve 43a corresponding to the second compression chamber 57b2 is set so as to keep the second compression chamber 57b2 closed.

  The dead volume DV4 of the second compression chamber 57b3 is equal to the second compression chamber 57b3 when the rotation angle of the drive shaft 3 is equal to or greater than the predetermined value R3 shown in FIG. The discharge valve 43a corresponding to the second compression chamber 57b3 is set so as to keep the second compression chamber 57b3 closed.

  In this compressor, as shown by the solid line J2 in FIG. 7, if the rotation angle of the drive shaft 3 is equal to or greater than the predetermined value R1 with the inclination angle of the swash plate 5 in the minimum state shown in FIG. With this setting, the discharge valve 43a corresponding to the second compression chamber 57b1 keeps the second compression chamber 57b1 closed. Next, when the rotational speed of the drive shaft 3 is equal to or greater than the predetermined value R2, the discharge valve 43a corresponding to the second compression chamber 57b2 maintains the second compression chamber 57b2 closed by setting the dead volume DV3 described above. Next, if the rotation speed of the drive shaft 3 is equal to or greater than the predetermined value R3, the discharge valve 43a corresponding to the second compression chamber 57b3 maintains the second compression chamber 57b3 closed by setting the dead volume DV4 described above. For this reason, as each second compression chamber 57b1, 57b2, 57b3 closes in stages, the increase rate of the discharge flow rate decreases in stages, and the slope of the solid line J2 decreases in stages.

  The compressor of the second embodiment can achieve the same operational effects as the compressor of the first embodiment. Moreover, in this compressor, since each 2nd compression chamber 57b1, 57b2, 57b3 closes in steps, the increase in the return force accompanying the increase in the rotation speed of the drive shaft 3 can be suppressed more finely.

(Example 3)
As shown in FIG. 8, in the compressor according to the third embodiment, the second groove 23b is employed instead of the first groove 9b according to the first embodiment. Other configurations of the third embodiment are the same as those of the first embodiment.

  A second groove 23b is formed in the surface of the valve plate 23 forming the second compression chambers 57b1, 57b2, 57b3 on the compression chamber 57 side. By appropriately setting the shape and depth of the second groove 23b, the dead volume DV2 of each of the second compression chambers 57b1, 57b2, and 57b3 is equal to the volume of the second groove 23b. , 57a2 and 57a3 are larger than the dead volume DV1.

  The compressor of the third embodiment can achieve the same operational effects as the compressors of the first and second embodiments.

Example 4
As shown in FIG. 9, the compressor of the fourth embodiment employs a third groove 21 c instead of the first groove 9 b according to the first embodiment. Other configurations of the fourth embodiment are the same as those of the first embodiment.

  A third groove 21c is recessed in the inner peripheral surface 21b of the cylinder bore 21a that forms the second compression chambers 57b1, 57b2, and 57b3. By appropriately setting the shape, depth, and the like of the third groove 21c, the dead volume DV2 of each of the second compression chambers 57b1, 57b2, and 57b3 is equivalent to the volume of the third groove 21c. , 57a2 and 57a3 are larger than the dead volume DV1.

  The compressor according to the third embodiment can achieve the same effects as the compressors according to the first to third embodiments.

  In the above, the present invention has been described with reference to the first to fourth embodiments. However, the present invention is not limited to the first to fourth embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  For example, the number and arrangement of the second compression chambers are not limited to the configuration of the embodiment. Further, the dead volume may be set large by combining any two or more of the first groove, the second groove, and the third groove.

  The present invention is applicable to an air conditioner such as a vehicle.

21 ... Cylinder block 25 ... Swash plate chamber 21a ... Cylinder bore 3 ... Drive shaft 5 ... Swash plate O ... Rotating shaft center 7 ... Link mechanism 57 ... Compression chamber 57b1, 57b2, 57b3 ... Second compression chamber 57a1, 57a2, 57a3 ... First Compression chamber 9 ... Piston 19 ... Head member (rear housing)
35 ... Discharge chamber 23 ... Valve plate 43a ... Discharge valve 51 ... Partition body (lug plate)
13a ... Moving body 13b ... Control pressure chamber 15 ... Control mechanism R1, R2, R3 ... Predetermined value DV ... Dead volume 9a ... Top surface of piston 9b ... First groove 23a ... Compression chamber side surface 23b ... Second of valve plate Groove 21b ... Inner peripheral surface of cylinder bore 21c ... Third groove

Claims (6)

A cylinder block formed with a swash plate chamber and a plurality of cylinder bores;
A drive shaft rotatably supported by the cylinder block;
A swash plate disposed in the swash plate chamber and rotated together with the drive shaft;
A link mechanism provided between the drive shaft and the swash plate, and allowing a change in the inclination angle of the swash plate with respect to a direction orthogonal to the rotational axis of the drive shaft;
A piston that is housed in each cylinder bore and reciprocates at a stroke according to the tilt angle by rotation of the swash plate to form a compression chamber in each cylinder bore;
A head member joined to the cylinder block and forming a discharge chamber on the compression chamber side;
A valve plate which is provided between the cylinder block and the head member and forms the compression chambers together with the cylinder bores and the pistons;
A discharge valve provided on the valve plate for opening and closing each compression chamber and the discharge chamber by a differential pressure between each compression chamber and the discharge chamber;
A partition provided in the swash plate chamber so as to be integrally rotatable with the drive shaft;
A movable body provided in the swash plate chamber and capable of rotating integrally with the drive shaft and moving in the rotational axis direction relative to the partition body to change the tilt angle;
A control pressure chamber that is partitioned by the partition body and the moving body, and moves the moving body so as to decrease the inclination angle by increasing an internal pressure;
A control mechanism for controlling the pressure in the control pressure chamber,
Each compression chamber has a first compression chamber and a second compression chamber in which a dead volume larger than the dead volume of the first compression chamber is set,
The variable displacement swash plate compressor, wherein the discharge valve keeps the second compression chamber closed when the rotational speed of the drive shaft becomes a predetermined value or more in a state where the inclination angle is minimum. Four or more cylinder bores are formed around the rotational axis,
The variable capacity swash plate compressor according to claim 1, wherein two or more second compression chambers are provided so as not to be adjacent to each other. Two or more second compression chambers have different dead volumes from each other,
3. The variable displacement swash plate compressor according to claim 1, wherein each discharge valve maintains the second compression chamber closed in a stepwise manner as the rotational speed of the drive shaft increases.   4. The second compression chamber according to claim 1, wherein the dead volume of the second compression chamber is set to be larger than that of the first compression chamber by a first groove provided in a top surface of the piston. 5. Variable capacity swash plate compressor.   The dead volume of the second compression chamber is set to be larger than that of the first compression chamber by a second groove recessed in the surface on the compression chamber side of the valve plate. A variable capacity swash plate compressor according to claim 1.   6. The second compression chamber according to any one of claims 1 to 5, wherein the dead volume is set larger than that of the first compression chamber by a third groove formed in an inner peripheral surface of the cylinder bore. Variable capacity swash plate compressor.

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