JP2005009422A - Capacity control mechanism for variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement mechanism capable of preventing a second control valve from improperly operating even in lowering of performance of a first control valve while preventing lowering of efficiency of a variable displacement compressor. <P>SOLUTION: The first control valve CV1 controls an opening of an air supply passage 29. In the second control valve CV2 composed of a spool valve, pressure in a downstream side of the first control valve CV1 in the air supply passage 29 is introduced to a back pressure chamber 78 through a valve inner passage 82. The second control valve CV2 opens and closes a first air bleed passage 27 with first valve parts 76a, 76b as the pressure acting on a back face 80 of a spool 76 is changed in accordance with the valve opening of the first control valve CV1. A second valve part 86 is provided on the back face 80 of the spool 76 to close the opening 82a in the back pressure chamber 78 of the valve inner passage 82 when the first valve parts 76a, 76b open the first air bleed passage 27 to the maximum opening in accordance with the closing of the air supply passage 29 by the first control valve CV1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention constitutes a refrigerant circulation circuit of an air conditioner, and is used for a variable displacement compressor having a configuration in which the discharge capacity is reduced when the crank chamber pressure is increased and the discharge capacity is increased when the crank chamber pressure is decreased. The present invention relates to a capacity control mechanism for controlling the discharge capacity of the variable capacity compressor.
[0002]
[Prior art]
As this type of capacity control mechanism, there is a structure that adjusts the pressure (crank pressure Pc) of the crank chamber 153 by a technique called inlet side control as shown in FIG. 7, for example.
[0003]
That is, in the variable displacement swash plate compressor (hereinafter simply referred to as a compressor), the crank chamber 153 and the suction chamber 155 are connected via the extraction passage 154. The compressor discharge chamber 151 and the crank chamber 153 are connected to each other via an air supply passage 152, and a control valve 156 is disposed in the air supply passage 152. Then, by adjusting the opening of the control valve 156, the amount of high-pressure refrigerant gas introduced into the crank chamber 153 via the air supply passage 152 is adjusted, and gas is led out from the crank chamber 153 via the extraction passage 154. The crank pressure Pc is determined from the balance with the amount.
[0004]
A fixed throttle 158 is disposed on the extraction passage 154, and the fixed throttle 158 slows out the refrigerant gas from the crank chamber 153 to the suction chamber 155. Therefore, even if the supply amount of the refrigerant gas from the discharge chamber 151 via the air supply passage 152 is small, the crank pressure Pc can be reliably increased. Therefore, if the control valve 156 increases the opening degree of the air supply passage 152, the crank pressure Pc increases rapidly, and good responsiveness can be obtained in the direction of decreasing the discharge capacity of the compressor.
[0005]
Further, the amount of blow-by gas from the cylinder bore 157 to the crank chamber 153 leaks to the suction chamber 155 via the extraction passage 154 or a kind of internal leakage from the discharge chamber 151 to the suction chamber 155 via the crank chamber 153. The amount of movement of the refrigerant gas can be reduced by the fixed throttle 158 as much as possible. As a result, it is possible to prevent a reduction in the efficiency of the compressor due to the provision of the capacity control mechanism.
[0006]
However, disposing the fixed throttle 158 on the bleed passage 154, on the other hand, slows down the pressure drop in the crank chamber 153, that is, the responsiveness deteriorates in the direction of increasing the discharge capacity of the compressor. It leads to things. In particular, when the compressor is started, the crank pressure Pc will increase excessively due to the vaporization of the liquid refrigerant accumulated in the crank chamber 153 and the fixed throttle 158 preventing the refrigerant gas from being led out from the crank chamber 153. And Therefore, even if the control valve 156 closes the supply passage 152 to increase the discharge capacity of the compressor immediately after the start of the compressor due to a request for cool down or the like, until the discharge capacity of the compressor actually increases. Has a problem that it takes time and the startability of the air conditioner deteriorates.
[0007]
In order to solve such a problem, for example, as shown in FIG. 8, in addition to the control valve (first control valve) 156, a second control valve 161 capable of adjusting the opening degree of the extraction passage 154 is provided. It has been proposed (see, for example, Patent Document 1).
[0008]
That is, in the supply passage 152, a region K is set on the crank chamber 153 side of the first control valve 156 (specifically, the valve opening adjustment position) and on the first control valve 156 side of the fixed throttle 169. ing. The second control valve 161 is a spool valve provided with a spool 162, and the pressure in the region K is introduced into the back pressure chamber 166 of the second control valve 161. The valve chamber 167 of the second control valve 161 constitutes a part of the extraction passage 154 and communicates with the suction chamber 155. The valve chamber 167 communicates with the crank chamber 153 via a valve hole 168 that forms an upstream portion of the extraction passage 154.
[0009]
The spool 162 is movably fitted in a spool holding recess 164 formed in the compressor housing. The spool 162 has a valve portion 162 a disposed in the valve chamber 167 and a back surface 162 b disposed in the back pressure chamber 166. The spool 162 (valve portion 162a) has a biasing force in the valve closing direction based on the pressure of the back pressure chamber 166 acting on the back surface 162b (pressure Pdk in the region K) and a biasing force in the valve opening direction of the biasing spring 165. Alternatively, the positioning is performed by a force based on the crank pressure Pc acting in the valve opening direction.
[0010]
Therefore, for example, if the first control valve 156 closes the air supply passage 152, the pressure Pdk in the back pressure chamber 166 of the second control valve 161 becomes substantially equal to the crank pressure Pc, and the spool 162 of the second control valve 161 is The valve hole 168 is set to the maximum opening degree by the biasing spring 165. If the second control valve 161 opens the bleed passage 154 greatly, derivation of the refrigerant from the crank chamber 153 to the suction chamber 155 is promoted. As a result, for example, if the first control valve 156 closes the supply passage 152 so as to increase the discharge capacity of the compressor immediately after the start of the compressor, the discharge capacity of the compressor can be increased quickly, and the air conditioner The startability of the can be improved.
[0011]
Since the urging spring 165 has a very weak urging force, the first control valve 156 opens the supply passage 152 even slightly so that the pressure Pdk in the region K becomes higher than the crank pressure Pc. For example, the spool 162 moves against the biasing spring 165, and the valve portion 162a sets the opening of the valve hole 168 to a minimum which is not zero. Accordingly, the second control valve 161 functions in the same manner as the above-described fixed throttle 158 (see FIG. 7) by the valve portion 162a having a minimum opening that is not zero, and the efficiency of the compressor is reduced due to the provision of the capacity control mechanism. Can be prevented.
[0012]
[Patent Document 1]
JP 2002-21721 (page 7-10, FIG. 1, FIG. 4, FIG. 5)
[0013]
[Problems to be solved by the invention]
However, even when the first control valve 156 is in a state where the air supply passage 152 is closed, the first control valve 156 may leak the refrigerant gas due to performance degradation due to deterioration over time. Accordingly, the refrigerant gas leaked from the first control valve 156 increases the pressure Pdk in the back pressure chamber 166 of the second control valve 161, and the second control valve 161 malfunctions, causing the extraction passage 154 to have a minimum opening. Sometimes. Therefore, the refrigerant gas is slowly led out from the crank chamber 153 to the suction chamber 155 through the extraction passage 154, and there is a problem that the startability of the air conditioner cannot be improved.
[0014]
In order to solve such a problem, even if the pressure Pdk in the back pressure chamber 166 is slightly increased by using a strong biasing force as the biasing spring 165, the valve by the spool 162 (valve portion 162a) is used. The maximum opening of the hole 168 may be maintained.
[0015]
However, if a strong biasing force is used as the biasing spring 165, the first control valve 156 opens the air supply passage 152 greatly and the pressure Pdk in the back pressure chamber 166 does not increase greatly. However, the bleed passage 154 cannot be set to the minimum opening. Therefore, in a state where the first control valve 156 opens the air supply passage 152, a period during which the second control valve 161 sets the bleed passage 154 to an opening other than the minimum opening (in other words, the second control valve 161 has the fixed throttle 158). There is a problem that the efficiency of the compressor is reduced.
[0016]
An object of the present invention is to provide a capacity control mechanism that can prevent the second control valve from malfunctioning due to a decrease in performance of the first control valve while preventing a decrease in efficiency of the variable capacity compressor.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, in the capacity control mechanism according to claim 1, an air supply passage connecting the crank chamber and the suction pressure region of the refrigerant circulation circuit, and an air supply passage connecting the crank chamber and the discharge pressure region of the refrigerant circulation circuit. A passage and a first control valve capable of adjusting the opening of the air supply passage are provided. Further, the capacity control mechanism includes a back pressure chamber into which pressure downstream of the valve opening adjustment position of the first control valve in the air supply passage is introduced through the introduction passage, and a part of the extraction passage. The first valve portion when the pressure of the back pressure chamber acting on the back surface has a valve chamber constituting, a first valve portion disposed in the valve chamber, and a back surface disposed in the back pressure chamber increases. A second control valve comprising: a valve body that reduces the opening degree of the bleed passage; and a biasing spring that urges the valve body in a direction in which the first valve portion increases the opening degree of the bleed passage. It has been.
[0018]
In the state where the first control valve opens the air supply passage, the second control valve is configured such that the pressure of the back pressure chamber is increased by the pressure supply from the discharge pressure region, whereby the opening degree of the extraction passage is increased by the first valve portion. Make it smaller. Accordingly, the pressure in the crank chamber is quickly increased, and the discharge capacity of the variable capacity compressor can be quickly reduced. Further, the second control valve is configured such that when the first control valve closes the air supply passage, the pressure supply from the discharge pressure region to the back pressure chamber is stopped, so that the opening of the extraction passage by the first valve portion. Is the maximum. Therefore, the pressure in the crank chamber is quickly reduced, and the discharge capacity of the variable capacity compressor can be increased quickly.
[0019]
And in this invention, the 2nd valve part is provided in the said back surface of the said valve body, and this 2nd valve part is the said introduction passage when the said 1st valve part makes the said extraction passage the maximum opening degree. The opening in the back pressure chamber is closed. Therefore, when the first control valve closes the supply passage and the second control valve has the extraction passage at the maximum opening, the pressure in the introduction passage rises due to gas leakage caused by the performance degradation of the first control valve. Even if it does, it can suppress by the 2nd valve part that the high voltage | pressure in this introduction channel | path is introduce | transduced into a back pressure chamber.
[0020]
Therefore, the high pressure in the introduction passage is not applied to the entire back surface of the spool, and the operation of the high pressure causes a malfunction in which the valve body moves in the direction of decreasing the opening degree of the first valve portion. It can be suppressed by a weak biasing spring. Further, by using a biasing spring with a weak biasing force, the period during which the second control valve makes the bleed passage the opening other than the minimum opening in the state where the first control valve opens the supply passage may increase. Therefore, it is possible to prevent the efficiency of the compressor from decreasing.
[0021]
According to a second aspect of the present invention, in the first aspect, the second valve portion is convex and tapered toward the opening of the introduction passage, and the second valve portion enters the introduction passage. The opening of the introduction passage can be closed. Therefore, the second valve portion is reliably brought into contact with the edge of the opening, and the opening can be reliably closed by the second valve portion.
[0022]
According to a third aspect of the present invention, in the first or second aspect, the introduction passage and the back pressure chamber constitute a part of the air supply passage. That is, the second valve portion of the second control valve closes the air supply passage on the downstream side of the first control valve when the first valve portion is in the maximum opening state. Therefore, in this state, the leaked gas is not supplied to the crank chamber even if the gas leaks due to the performance deterioration of the first control valve, and the compressor according to the blockage of the supply passage by the first control valve. The maximum discharge capacity operation can be more reliably maintained.
[0023]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the second valve portion is made of an elastic material. Therefore, due to the elastic deformation of the second valve portion, the second valve portion is reliably brought into contact with the edge of the opening, and the opening is reliably closed.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in a variable capacity swash plate compressor (hereinafter simply referred to as a compressor) used in a vehicle air conditioner to compress refrigerant gas will be described.
[0025]
(Compressor)
As shown in FIG. 1, the compressor is joined and fixed to a cylinder block 11, a front housing 12 joined and fixed to the front end of the cylinder block 11, and a valve / port forming body 13 to the rear end of the cylinder block 11. And a rear housing 14. The cylinder block 11, the front housing 12, and the rear housing 14 constitute a compressor housing.
[0026]
A crank chamber 15 is defined in an area surrounded by the cylinder block 11 and the front housing 12. A drive shaft 16 is rotatably supported in the crank chamber 15. A lug plate 17 is fixed on the drive shaft 16 in the crank chamber 15 so as to be integrally rotatable.
[0027]
The front end portion of the drive shaft 16 is operatively connected to a vehicle engine E as an external drive source via a power transmission mechanism PT. The power transmission mechanism PT may be a clutch mechanism (for example, an electromagnetic clutch) capable of selecting transmission / cutoff of power by electric control from the outside, or a constant transmission type clutchless without such a clutch mechanism. It may be a mechanism (for example, a belt / pulley combination). In the present embodiment, a clutchless type power transmission mechanism PT is employed.
[0028]
A swash plate 18 as a cam plate is accommodated in the crank chamber 15. The swash plate 18 is supported by the drive shaft 16 so as to be slidable and tiltable. The hinge mechanism 19 is interposed between the lug plate 17 and the swash plate 18. Therefore, the swash plate 18 can be rotated synchronously with the lug plate 17 and the drive shaft 16 by the hinge connection with the lug plate 17 via the hinge mechanism 19 and the support of the drive shaft 16. It can be tilted with respect to the drive shaft 16 while being slid in the axial direction.
[0029]
A plurality of cylinder bores 11 a (only one is shown in the drawing) are formed through the cylinder block 11 so as to surround the drive shaft 16. The single-headed piston 20 is accommodated in each cylinder bore 11a so as to be able to reciprocate. The front and rear openings of the cylinder bore 11a are closed by a valve / port forming body 13 and a piston 20, and a compression chamber whose volume changes in accordance with the reciprocating motion of the piston 20 is defined in the cylinder bore 11a. Each piston 20 is anchored to the outer periphery of the swash plate 18 via the shoe 10. Therefore, the rotational motion of the swash plate 18 accompanying the rotation of the drive shaft 16 is converted into the reciprocating linear motion of the piston 20 via the shoe 10.
[0030]
Between the valve / port forming body 13 and the rear housing 14, a suction chamber 21 located in the central region and a discharge chamber 22 surrounding the suction chamber 21 are formed. Corresponding to each cylinder bore 11a, the valve / port forming body 13 is formed with a suction port 23, a suction valve 24 for opening and closing the port 23, a discharge port 25 and a discharge valve 26 for opening and closing the port 25. . The suction chamber 21 communicates with each cylinder bore 11 a via the suction port 23, and each cylinder bore 11 a communicates with the discharge chamber 22 via the discharge port 25.
[0031]
The refrigerant gas in the suction chamber 21 is sucked into the cylinder bore 11a via the suction port 23 and the suction valve 24 by the forward movement from the top dead center position to the bottom dead center side of each piston 20. The refrigerant gas sucked into the cylinder bore 11a is compressed to a predetermined pressure by the backward movement from the bottom dead center position of the piston 20 to the top dead center side, and is discharged to the discharge chamber 22 through the discharge port 25 and the discharge valve 26. Is done.
[0032]
The inclination angle of the swash plate 18 (angle formed between the plane perpendicular to the axis of the drive shaft 16) is changed according to the change of the pressure in the crank chamber 15 (crank pressure Pc), and the minimum inclination angle (FIG. 1). And a maximum inclination angle (state indicated by a two-dot chain line in FIG. 1).
[0033]
(Capacity control mechanism)
The capacity control mechanism for controlling the crank pressure Pc involved in the tilt angle control of the swash plate 18 is provided in the compressor housing shown in FIG. 1 as a first bleed passage 27 and a second bleed air. The passage 28, the air supply passage 29, the first control valve CV1, and the second control valve CV2 are configured.
[0034]
The first and second extraction passages 27 and 28 connect the crank chamber 15 and the suction chamber 21 which is a suction pressure (Ps) region, respectively. The second bleed passage 28 is provided with a fixed throttle 28a on the way. The air supply passage 29 connects the discharge chamber 22, which is a discharge pressure (Pd) region, and the crank chamber 15. In the middle of the air supply passage 29, a first control valve CV1 capable of adjusting the opening degree of the air supply passage 29 is disposed. As will be described later, the first extraction passage 27 and the supply passage 29 share a part of the passage.
[0035]
By adjusting the opening degree of the first control valve CV1 and the second control valve CV2, the amount of high-pressure discharge gas introduced into the crank chamber 15 via the air supply passage 29 and the first and second extraction passages 27, The balance with the amount of gas discharged from the crank chamber 15 via the control 28 is controlled, and the crank pressure Pc is determined. In response to the change in the crank pressure Pc, the difference between the crank pressure Pc through the piston 20 and the internal pressure of the cylinder bore 11a is changed, and the inclination angle of the swash plate 18 is changed. Is adjusted.
[0036]
For example, when the opening degree of the first control valve CV1 is reduced and the crank pressure Pc is reduced, the inclination angle of the swash plate 18 is increased and the discharge capacity of the compressor is increased. Conversely, when the opening of the first control valve CV1 is increased and the crank pressure Pc increases, the inclination angle of the swash plate 18 decreases and the discharge capacity of the compressor decreases. The minimum discharge capacity of the compressor is set to zero or near zero.
[0037]
(Refrigerant circulation circuit)
As shown in FIG. 1, the refrigerant circulation circuit (refrigeration cycle) of the vehicle air conditioner includes the above-described compressor and the external refrigerant circuit 30. The external refrigerant circuit 30 includes, for example, a condenser 31, an expansion valve 32, and an evaporator 33. In the downstream area of the external refrigerant circuit 30, a refrigerant flow pipe 35 connecting the outlet of the evaporator 33 and the suction chamber 21 of the compressor is provided. In the upstream area of the external refrigerant circuit 30, a refrigerant flow pipe 36 that connects the discharge chamber 22 of the compressor and the inlet of the condenser 31 is provided. The compressor sucks and compresses the refrigerant gas introduced into the suction chamber 21 from the downstream area of the external refrigerant circuit 30 and discharges the compressed gas to the discharge chamber 22 connected to the upstream area of the external refrigerant circuit 30.
[0038]
(First control valve)
As shown in FIG. 2, the first control valve CV <b> 1 includes an inlet valve portion that occupies the upper half portion and a solenoid portion 60 that occupies the lower half portion. The inlet valve section adjusts the opening degree (throttle amount) of the air supply passage 29 that connects the discharge chamber 22 and the crank chamber 15. The solenoid unit 60 is a kind of electromagnetic actuator for energizing and controlling the valve rod 40 disposed in the first control valve CV1 based on energization control from the outside. The valve rod 40 is a rod-shaped member including a partition wall portion 41 that is a distal end portion, a connecting portion 42, a valve body portion 43 that is substantially in the center, and a guide rod portion 44 that is a proximal end portion.
[0039]
The valve housing 45 of the first control valve CV1 includes an upper half valve body 45a and a lower half actuator housing 45b. In the valve body 45a, a valve storage chamber 46, a communication passage 47, and a pressure sensitive chamber 48 are partitioned in order from the lower side of the drawing. A valve rod 40 is disposed in the valve housing chamber 46 and the communication passage 47 so as to be movable in the axial direction (vertical direction in the drawing) of the valve housing 45. The communication passage 47 and the pressure sensing chamber 48 are blocked by the upper end portion of the valve rod 40 inserted into the communication passage 47.
[0040]
A port 51 communicating with the valve housing chamber 46 and a port 52 communicating with the communication passage 47 are formed on the peripheral wall of the valve body 45a. The valve storage chamber 46 communicates with the discharge chamber 22 via the port 51 and the discharge chamber side passage 84. The communication passage 47 communicates with the crank chamber 15 via the port 52, the first control valve side passage 83, the second control valve CV 2, and the crank chamber side passage 75. These discharge chamber side passage 84, port 51, valve storage chamber 46, communication passage 47, port 52, first control valve side passage 83, second control valve CV 2, and crank chamber side passage 75 define the air supply passage 29. It is configured.
[0041]
A valve body 43 of the valve rod 40 is disposed in the valve storage chamber 46. In the valve body 45a, the step portion located at the boundary between the valve accommodating chamber 46 and the communication passage 47 forms a valve seat 53, and the communication passage 47 forms a valve hole. When the valve rod 40 moves upward from the position shown in FIG. 2, that is, from the open state of the communication passage 47 (the air supply passage 29) to a position where the valve body 43 is seated on the valve seat 53, the valve body 43 is moved. The communication passage 47 (air supply passage 29) is blocked by contacting the valve seat 53.
[0042]
A bellows 50 is accommodated in the pressure sensitive chamber 48. An upper end portion of the bellows 50 is fixed to the valve housing 45. The upper end of the valve rod 40 is fitted to the lower end of the bellows 50. The pressure-sensitive chamber 48 is partitioned into a first pressure chamber 54 that is an internal space of the bellows 50 and a second pressure chamber 55 that is an external space by a bellows 50 having a bottomed cylindrical shape.
[0043]
As shown in FIG. 1, a throttle 36 a is disposed on the flow pipe 36 from the discharge chamber 22 to the external refrigerant circuit 30. As shown in FIG. 2, the first pressure chamber 54 is connected to the flow pipe 36 via the first pressure guiding passage 37 at a first pressure monitoring point P1 on the upstream side (the discharge chamber 22 side) of the throttle 36a. ing. The second pressure chamber 55 is connected to the flow pipe 36 via the second pressure guiding passage 38 at a second pressure monitoring point P2 downstream of the throttle 36a. Accordingly, the refrigerant gas monitoring pressure PdH at the first pressure monitoring point P1 is introduced into the first pressure chamber 54, and the refrigerant gas monitoring at the second pressure monitoring point P2 is introduced into the second pressure chamber 55. Pressure PdL is introduced.
[0044]
The bellows 50 is displaced at its lower end in accordance with the differential pressure (PdH−PdL) before and after the throttle 36a, and reflects the variation in the differential pressure in the positioning of the valve rod 40 (valve element 43). The differential pressure before and after the throttle 36a reflects the refrigerant flow rate in the refrigerant circulation circuit. For example, the differential pressure increases as the refrigerant flow rate increases, and conversely, the differential pressure decreases as the refrigerant flow rate decreases. In addition, the bellows 50 operates the valve body 43 so that the discharge capacity of the compressor is changed to the side that cancels the fluctuation of the differential pressure before and after the throttle 36a.
[0045]
The solenoid portion 60 includes a cylindrical cylinder 61 with a bottom at the center of the actuator housing 45b. A cylindrical fixed iron core 62 is fitted and fixed in the upper opening of the housing cylinder 61. By inserting the fixed iron core 62, a solenoid chamber 63 is defined in the lowermost part of the housing cylinder 61.
[0046]
A movable iron core 64 is accommodated in the solenoid chamber 63 so as to be movable in the axial direction. A guide hole 65 extending in the axial direction is formed through the center of the fixed iron core 62, and the guide rod portion 44 of the valve rod 40 is disposed in the guide hole 65 so as to be movable in the axial direction. The guide rod portion 44 is fitted and fixed to the movable iron core 64 in the solenoid chamber 63. Therefore, the movable iron core 64 and the valve rod 40 move up and down as a unit at all times.
[0047]
In the solenoid chamber 63, a rod urging spring 66 made of a coil spring is accommodated between the fixed iron core 62 and the movable iron core 64. The rod urging spring 66 urges the valve rod 40 in a direction in which the valve body portion 43 is separated from the valve seat portion 53.
[0048]
On the outer peripheral side of the fixed iron core 62 and the movable iron core 64, a coil 67 is wound around the iron cores 62 and 64. A drive signal is supplied to the coil 67 from the drive circuit 68a based on a command from the control device 68 according to the cooling load or the like. Accordingly, an electromagnetic force (electromagnetic attraction force) having a magnitude corresponding to the amount of power supplied to the coil 67 is generated between the fixed iron core 62 and the movable iron core 64, and this electromagnetic force is transmitted through the movable iron core 64 to the valve rod. 40 (valve element 43). The energization control to the coil 67 is performed by adjusting the voltage applied to the coil 67, and duty control is employed in this embodiment.
[0049]
In the first control valve CV1 configured as described above, the positioning of the valve body 43 by the bellows 50 is performed by changing the electromagnetic force applied to the valve body 43 by the solenoid unit 60 according to the amount of electric power supplied from the outside. The control target (set differential pressure) of the differential pressure before and after the throttle 36a as a reference can be changed. That is, the first control valve CV <b> 1 internally autonomously responds to the variation in the differential pressure so as to maintain the set differential pressure determined by the amount of power supplied to the coil 67. Is positioned.
[0050]
Further, the set differential pressure of the first control valve CV1 can be changed from the outside by adjusting the amount of power supplied to the coil 67. That is, for example, when the duty ratio commanded from the control device 68 to the drive circuit 68a increases, the electromagnetic biasing force of the solenoid unit 60 increases and the set differential pressure of the first control valve CV1 increases. When the set differential pressure is increased and changed, the discharge capacity of the compressor tends to increase. Conversely, when the duty ratio commanded from the control device 68 to the drive circuit 68a decreases, the electromagnetic biasing force of the solenoid unit 60 decreases, and the set differential pressure of the first control valve CV1 decreases. When the set differential pressure is decreased and changed, the discharge capacity of the compressor tends to decrease.
[0051]
The compressor of this embodiment is a so-called clutchless type compressor (clutchless compressor), and the drive shaft 16 is always rotated when the engine E is driven. However, when air conditioning is not required, the air conditioner switch is turned off to stop energization of the coil 67 (zero duty ratio), the swash plate 18 is set to the minimum inclination angle, and the discharge capacity of the compressor is uniquely minimized. Since the capacity is zero (or near zero), the rotation of the drive shaft 16 substantially stops the supply of refrigerant from the compressor to the external refrigerant circuit 30 and stops the refrigeration cycle.
[0052]
(Second control valve)
As shown in FIGS. 1, 3 and 4, the rear end surface 14a of the rear housing 14 is formed with an accommodation hole 70 for accommodating the second control valve CV2. A valve housing 71 is fitted and fixed in the accommodation hole 70. The valve housing 71 has a cylindrical portion 72 having an outer diameter smaller than the receiving hole 70 and a fitting portion that is connected to the cylindrical portion 72 on the opening side of the receiving hole 70 and is fitted and fixed to the receiving hole 70. 73. The valve housing 71 is pushed into the accommodation hole 70 to a position where the tip of the cylindrical portion 72 contacts the inner bottom surface 70 a of the accommodation hole 70.
[0053]
A housing chamber 74 is defined in the tubular portion 72 by being surrounded by the end surface 73 a of the fitting portion 73 facing the tubular portion 72 and the inner bottom surface 70 a of the housing hole 70. A communication space 79 is provided between the outer peripheral surface of the cylindrical portion 72 and the inner peripheral surface of the accommodation hole 70. The communication space 79 is connected to the crank chamber 15 via a crank chamber side passage 75.
[0054]
A spool 76 as a valve element is accommodated in the accommodating chamber 74 so as to be movable in the extending direction of the cylindrical portion 72, that is, in the horizontal direction of the drawing. The spool 76 is slidable between a position where it comes into contact with the inner bottom surface 70 a of the accommodation hole 70 and a position where it comes into contact with the end surface 73 a of the fitting portion 73. The spool 76 has a bottomed cylindrical shape with the end surface 73a side of the fitting portion 73 as a bottom.
[0055]
The space before and after the spool 76 in the storage chamber 74 is blocked by the sliding contact between the inner peripheral surface of the storage chamber 74 and the outer peripheral surface of the spool 76. Of the space before and after the blocked spool 76, the space on the inner bottom surface 70a side of the accommodation hole 70 forms the valve chamber 77, and the space on the end surface 73a side of the fitting portion 73 forms the back pressure chamber 78. . In the spool 76, the opening side end surface disposed in the valve chamber 77 forms the end surface valve portion 76 a, and the outer bottom surface disposed in the back pressure chamber 78 forms the back surface 80. The spool 76 contacts the inner bottom surface 70a of the accommodation hole 70 with the end surface valve portion 76a.
[0056]
The tubular portion 72 of the valve housing 71 has a first through hole 72a communicating between the inside and the outside of the tubular portion 72, and is located closer to the fitting portion 73 than the first through hole 72a, and the inside and outside of the tubular portion 72 are disposed inside and outside. The 2nd through-hole 72b which connects is formed.
[0057]
The first through hole 72a communicates the valve chamber 77 and the communication space 79 in a state where the spool 76 is in contact with the end surface 73a of the fitting portion 73 (state shown in FIG. 4). The first through hole 72 a is blocked by the region on the valve chamber 77 side (first peripheral valve portion 76 b) on the outer peripheral surface of the spool 76 when the spool 76 is in contact with the inner bottom surface 70 a of the accommodation hole 70. The valve chamber 77 and the communication space 79 are blocked (state shown in FIG. 3).
[0058]
The second through hole 72b allows the back pressure chamber 78 and the communication space 79 to communicate with each other with the spool 76 in contact with the inner bottom surface 70a of the accommodation hole 70 (state shown in FIG. 3). The second through hole 72b is blocked by a region (second peripheral surface valve portion 76c) on the back pressure chamber 78 side on the outer peripheral surface of the spool 76 when the spool 76 is in contact with the end surface 73a of the fitting portion 73. Thus, the back pressure chamber 78 and the communication space 79 are blocked (state shown in FIG. 4).
[0059]
The valve chamber 77 is connected to the suction chamber 21 via a suction chamber side passage 81 formed in the rear housing 14. The suction chamber side passage 81 is opened on the inner bottom surface 70 a of the accommodation hole 70 inside the annular region (seal region) where the end surface valve portion 76 a of the spool 76 contacts.
[0060]
Therefore, when the spool 76 is in contact with the inner bottom surface 70a of the accommodation hole 70, the valve chamber 77 is blocked from the outside and the inside with the seal region of the end face valve portion 76a as a boundary, and the first through hole 72a. Is closed by the first peripheral valve portion 76b, and the space between the suction chamber side passage 81 and the communication space 79 (crank chamber side passage 75) is blocked (state of FIG. 3). When the spool 76 is in contact with the end surface 73a of the fitting portion 73, the valve chamber 77 is opened between the outside and the inside with the seal region of the end surface valve portion 76a as a boundary, and the first through hole 72a is formed. The suction chamber side passage 81 and the communication space 79 (crank chamber side passage 75) are in communication with each other (opened by the first peripheral valve portion 76b of the spool 76) (state of FIG. 4).
[0061]
In the present embodiment, the first bleed passage 27 is configured by the suction chamber side passage 81, the valve chamber 77, the first through hole 72 a, the communication space 79, and the crank chamber side passage 75 shared with the air supply passage 29. Has been. Therefore, in the spool 76, the end face valve portion 76a and the first circumferential surface valve portion 76b that open and close between the suction chamber side passage 81 and the communication space 79 are the first valve that can adjust the opening degree of the first extraction passage 27. Can be grasped as a part.
[0062]
The back pressure chamber 78 is connected to the port of the first control valve CV1 via a valve inner passage 82 formed in the fitting portion 73 of the valve housing 71 and a first control valve side passage 83 constituting the air supply passage 29. 52. The intra-valve passage 82 is opened at the center of the end surface 73a of the fitting portion 73 in the back pressure chamber 78 (opening 82a). Therefore, the high-pressure refrigerant gas from the discharge chamber 22 is introduced into the back pressure chamber 78 through the discharge chamber side passage 84, the first control valve CV1, the first control valve side passage 83, and the valve passage 82 in the open state. The That is, in the back pressure chamber 78, the pressure Pdk on the downstream side of the valve opening adjustment position (valve seat portion 53) of the first control valve CV1 in the air supply passage 29 passes through the valve passage 82 as the introduction passage. Introduced.
[0063]
The refrigerant gas introduced from the discharge chamber 22 into the back pressure chamber 78 is introduced into the crank chamber 15 through the second through hole 72b, the communication space 79, and the crank chamber side passage 75. That is, in the second control valve CV <b> 2, the valve passage 82, the back pressure chamber 78, the second through hole 72 b and the communication space 79 constitute the air supply passage 29.
[0064]
The spool 76 reduces the opening degree of the first extraction passage 27 by the inner bottom surface 70 a side of the accommodation hole 70, that is, the first valve portions 76 a and 76 b, by a force based on the pressure Pdk of the back pressure chamber 78 acting on the back surface 80. Is biased to the side. In the spool 76, the end surface 73 a side of the fitting portion 73, that is, the first valve portions 76 a and 76 b is connected to the first extraction passage 27 by a force based on the suction pressure Ps introduced into the valve chamber 77 acting on the end surface valve portion 76 a side. It is energized to the side which increases the opening degree.
[0065]
In the valve chamber 77, an urging spring 85 made up of a coil spring is disposed in the spool 76. The urging spring 85 has a movable end abutting against the spool 76 and a fixed end accommodated and held in an accommodation groove 70 b formed in the inner bottom surface 70 a of the accommodation hole 70. The urging spring 85 urges the spool 76 in a direction in which the first valve portions 76 a and 76 b increase the opening degree of the first extraction passage 27.
[0066]
That is, the spool 76 has a biasing force in the valve closing direction of the first valve portions 76a and 76b based on the pressure Pdk of the back pressure chamber 78 and a valve of the first valve portions 76a and 76b based on the pressure Ps of the valve chamber 77. Positioning is performed by a balance between the biasing force in the opening direction and the biasing force in the valve opening direction of the first valve portions 76a and 76b by the biasing spring 85.
[0067]
In the present embodiment, the back surface 80 of the spool 76 is provided with a second valve portion 86 capable of opening and closing the opening 82a in the back pressure chamber 78 of the valve passage 82 in accordance with the displacement position of the spool 76. Yes. The second valve portion 86 projects from the central portion of the back surface 80 of the spool 76 facing the opening 82 a of the valve passage 82. The second valve portion 86 has a circular cross section and has a tapered shape with a small diameter on the tip side. The taper shape of the second valve portion 86 is set such that the base end (back surface 80) side has a larger diameter than the opening 82a of the valve passage 82 and the distal end has a smaller diameter than the opening 82a. The second valve portion 86 is made of an elastic material such as synthetic rubber or synthetic resin.
[0068]
As shown in FIG. 4, the movement of the spool 76 toward the fitting portion 73 is restricted by the second valve portion 86 coming into contact with the end surface 73 a of the fitting portion 73. In a state where movement of the spool 76 is restricted by contact with the end surface 73a of the fitting portion 73, in other words, in a state where the first bleed passage 27 is fully opened (maximum opening) by the first valve portions 76a and 76b, the second valve The distal end side of the portion 86 enters the valve passage 82 through the opening 82a, and the tapered surface 86a of the second valve portion 86 is brought into contact with the edge of the opening 82a of the valve passage 82 in an annular region, thereby causing back pressure. The chamber 78 is blocked from the valve passage 82. Therefore, in this state, the second through hole 72b is blocked by the second peripheral valve portion 76c of the spool 76, and the first control valve side passage 83 and the communication space 79 (crank chamber side passage 75) Is blocked.
[0069]
On the contrary, as shown in FIG. 3, the state where the spool 76 is restricted in movement by contact with the inner bottom surface 70a of the accommodation hole 70, in other words, the first bleed passage 27 by the first valve portions 76a and 76b. In the closed state, the second valve portion 86 is separated from the end surface 73 a of the fitting portion 73 and opens the opening 82 a of the valve passage 82. Therefore, in this state, the second through hole 72b is opened by the second peripheral valve portion 76c of the spool 76, and the first control valve side passage 83 and the communication space 79 (crank chamber side passage 75) Is communicated.
[0070]
(Operating characteristics of the second control valve)
As shown in FIG. 3, in the second control valve CV2, in the state where the first valve portions 76a and 76b of the spool 76 have the first bleed passage 27 smaller in opening than the fully opened state, The valve portion 86 opens between the back pressure chamber 78 and the valve passage 82, and the pressure Pdk of the valve passage 82 is introduced into the back pressure chamber 78. Accordingly, in the second control valve CV2, when the axial cross-sectional area of the back pressure chamber 78 is “SA” and the urging force of the urging spring 85 is “f”, the second control valve CV2 is connected to the first bleed passage 27. The conditional expression for increasing the opening is
(Pdk−Ps) SA <f Conditional expression (1)
It can be expressed.
[0071]
As shown in FIG. 4, in the second control valve CV2, when the first valve portions 76a and 76b of the spool 76 fully open the first bleed passage 27, the second valve portion 86 of the spool 76 has a back pressure. The chamber 78 and the valve passage 82 are blocked, and the pressure Pdk of the valve passage 82 is not introduced into the back pressure chamber 78. Accordingly, the pressure Pdk in the valve passage 82 only acts on the second valve portion 86 with respect to the back surface 80 of the spool 76. Therefore, when the cross-sectional area perpendicular to the axis of the opening 82a of the intra-valve passage 82 is “SB (<SA)”, the second control valve CV2 in a state where the first extraction passage 27 is fully opened opens the first extraction passage 27. The conditional expression for decreasing the degree is
(Pdk−Ps) SB> f Conditional expression (2)
It can be expressed.
[0072]
Now, when the engine E of the vehicle is stopped and a predetermined time or more elapses, the refrigerant circulation circuit is equalized at a low pressure, and the pressure Pdk and the suction pressure Ps become equal. Therefore, since conditional expression 1 is satisfied and conditional expression 2 is not satisfied, the spool 76 is moved by the biasing spring 85 and the second valve portion 86 blocks the air supply passage 29 as shown in FIG. The first valve portions 76a and 76b fully open the first bleed passage 27.
[0073]
In a compressor of a general vehicle air conditioner, when the refrigerant is present on the low pressure side of the external refrigerant circuit 30 with the engine E stopped for a long time, the crank chamber 15 and the suction chamber 21 are connected to the first and second bleed air. Due to the communication through the passages 27 and 28, the liquid refrigerant flows into the crank chamber 15 through the suction chamber 21. In particular, when the temperature on the vehicle interior side is high and the temperature on the engine room side where the compressor is disposed is low, a large amount of liquid refrigerant flows into the crank chamber 15 through the suction chamber 21 and is stopped as it is. It will be.
[0074]
For this reason, when the engine E is started and the compressor starts to be driven (as described above, the power transmission mechanism PT is a clutchless type), it is scratched by the influence of heat generated by the engine E and the swash plate 18. As a result, the liquid refrigerant is vaporized, and the crank pressure Pc tends to increase regardless of the opening of the first control valve CV1.
[0075]
Here, for example, if the interior of the vehicle is hot when the engine E is started, the control device 68 commands the maximum duty ratio to the drive circuit 68a to perform the cool-down based on the cooling request of the occupant, and the first control valve CV1. Maximize the set differential pressure. Therefore, the first control valve CV1 closes the air supply passage 29, and the high pressure refrigerant gas is not supplied from the discharge chamber 22 to the back pressure chamber 78 and the crank chamber 15 of the second control valve CV2. Therefore, even when the liquid refrigerant is vaporized in the crank chamber 15, the state where the force based on the difference between the pressure Pdk and the suction pressure Ps does not exceed the urging force f of the urging spring 85, that is, the state where the conditional expression 2 is not satisfied is continued. The Rukoto.
[0076]
As a result, the spool 76 of the second control valve CV2 is maintained in a state in which the first valve portions 76a and 76b have the first extraction passage 27 at the maximum opening (fully opened) by the biasing force f of the biasing spring 85. The liquid refrigerant in the crank chamber 15 is promptly led out to the suction chamber 21 through the fully opened first extraction passage 27 in a liquid state or at least a part of which is vaporized. Therefore, the crank pressure Pc is maintained in a low state corresponding to the blockage of the supply passage 29 by the first control valve CV1, and the compressor quickly increases the inclination angle of the swash plate 18 to maximize the discharge capacity. .
[0077]
As long as the first control valve CV1 is in the state of closing the air supply passage 29 even after the liquid refrigerant is discharged from the crank chamber 15, as described above, the first valve portions 76a and 76b of the second control valve CV2 are used. As a result, the first bleed passage 27 is largely opened. Therefore, even if the amount of blow-by gas from the cylinder bore 11a to the crank chamber 15 becomes larger than the initial assumption at the time of design due to, for example, wear of the piston 20, the blow-by gas passes through the first and second extraction passages 27 and 28. As a result, it is quickly led out to the suction chamber 21. Therefore, the crank pressure Pc can be maintained at a pressure substantially equal to the suction pressure Ps, and the maximum inclination angle of the swash plate 18, that is, the maximum discharge capacity operation (so-called 100% capacity operation) of the compressor can be reliably maintained. .
[0078]
If the passenger compartment is cooled to a certain extent by the maximum discharge capacity operation of the compressor, the control device 68 decreases the duty ratio commanded to the drive circuit 68a from the maximum. Accordingly, the first control valve CV1 opens the supply passage 29, and the pressure Pdk in the valve passage 82 rises higher than the pressure Ps in the valve chamber 77. Therefore, Conditional Expression 2 is satisfied, and the opening degree of the first valve portions 76a and 76b decreases from the fully opened state against the urging force f of the urging spring 85 as shown in FIG. Moved to.
[0079]
In the second control valve CV2, in the state where the first valve portions 76a and 76b of the spool 76 open the first extraction passage 27 smaller than the fully opened position, the second valve portion 86 of the spool 76 has the back. The space between the pressure chamber 78 and the valve passage 82 is opened. Therefore, the conditional expression for the second control valve CV2 that opens the first bleed passage 27 to an open state other than the fully open state reduces the opening degree of the first bleed passage 27 is:
(Pdk−Ps) SA> f Conditional expression (3)
It can be expressed. Since “SA> SB”, if the urging force f of the urging spring 85 is the same, the conditional expression (3) indicates that the difference between the pressure Pdk in the valve passage 82 and the pressure Ps in the valve chamber 77 (Pdk− Even if Ps) is smaller than the minimum value at which the conditional expression (2) can be satisfied, it can be satisfied. Accordingly, the spool 76 released from the fully opened state of the first bleed passage 27 due to the establishment of the conditional expression (2) does not stop halfway through the establishment of the conditional expression (3), and the opening degree of the first bleed passage 27 is increased. It is moved in the decreasing direction. Since the urging spring 85 has a weak urging force f, the spool 76 released from the fully opened state of the first bleed passage 27 quickly moves to the closed state of the first bleed passage 27. Is done.
[0080]
Therefore, the crank pressure Pc is quickly increased by opening the supply passage 29 by the first control valve CV1 and closing the first extraction passage 27 by the second control valve CV2, and the compressor quickly increases the inclination angle of the swash plate 18. To reduce the discharge capacity.
[0081]
Further, the first extraction passage 27 is closed by the second control valve CV2, so that the short circuit (leakage) amount of the compressed refrigerant gas from the discharge chamber 22 to the crank chamber 15 and then the suction chamber 21 is reduced. The amount can be reduced by only 28, and a reduction in the efficiency of the compressor can be suppressed. Furthermore, the refrigerant circulation circuit of the present embodiment has a configuration in which the refrigerant circulation is stopped by setting the compressor to the minimum discharge capacity (so-called clutchless compressor off operation), but the first control valve CV2 performs the first operation. Closing the extraction passage 27 also leads to ensuring that the compressor is turned off.
[0082]
According to the present embodiment having the above configuration, the following effects can be obtained.
(1) As described in the prior art, when the performance of the first control valve CV1 is deteriorated due to aging or the like, the first control valve CV1 is driven at the maximum duty ratio (the supply passage 29 is blocked). The refrigerant gas may leak. When the first control valve CV1 leaks the refrigerant gas, the pressure Pdk in the valve passage 82 increases, and the opening of the first extraction passage 27 acting on the spool 76 based on the pressure Pdk is decreased. The momentum increases.
[0083]
However, the spool 76 of the second control valve is provided with a second valve portion 86, and the second valve portion 86 is not in the valve state when the second control valve CV 2 fully opens the first extraction passage 27. The opening 82a in the back pressure chamber 78 of the passage 82 is closed. Accordingly, only the pressure Pdk of the valve passage 82 is applied to the second valve portion 86 on the back surface 80 of the spool 76, and the pressure Pdk of the valve passage 82 is applied to a portion other than the second valve portion 86 on the back surface 80. There is no effect (see conditional expression (2)). Therefore, even if the first control valve CV1 in the state in which the supply passage 29 is closed has a gas leak due to its performance degradation, the first extraction passage 27 is fully opened by the biasing spring 85 having a weak biasing force f. The state can be maintained, and the malfunction of the second control valve CV2 can be suppressed. As a result, the maximum inclination angle of the swash plate 18, that is, the maximum discharge capacity operation (so-called 100% capacity operation) of the compressor can be reliably maintained.
[0084]
Further, by using the biasing spring 85 having a weak biasing force, the second control valve CV1 does not greatly increase the pressure Pdk of the back pressure chamber 78 by opening the air supply passage 29 greatly. CV2 can make the 1st extraction passage 27 into the minimum opening. Therefore, in the state where the first control valve CV1 opens the air supply passage 29, the period during which the second control valve CV2 makes the first bleed passage 27 other than the closed opening does not increase, and the efficiency of the compressor is reduced. Can be prevented.
[0085]
(2) The second valve portion 86 of the second control valve CV2 is convex and tapered so as to enter the valve passage 82. Accordingly, the opening 82a of the in-valve passage 82 can be reliably closed by the second valve portion 86.
[0086]
(3) The back pressure chamber 78 of the second control valve CV2 and the valve passage 82 for introducing the refrigerant gas from the discharge chamber 22 into the back pressure chamber 78 constitute a part of the air supply passage 29. Yes. That is, the second valve portion 86 of the second control valve CV2 closes the air supply passage 29 on the downstream side of the first control valve CV1 when the first control valve CV1 closes the air supply passage 29. Therefore, in this state, the leaked refrigerant gas is not supplied to the crank chamber 15 due to a gas leak due to the performance deterioration of the first control valve CV1, and the maximum inclination angle of the swash plate 18, that is, the maximum discharge of the compressor. Capacity operation can be maintained more reliably.
[0087]
(4) The second control valve CV2 opens and closes the air supply passage 29 at a plurality of locations (in this embodiment, two locations of the second peripheral valve portion 76c and the second valve portion 86). Therefore, for example, the supply passage 29 can be reliably closed by the second control valve CV2, and the refrigerant gas leaked from the first control valve CV1 can be more effectively prevented from being supplied to the crank chamber 15.
[0088]
(5) The second valve portion 86 is made of an elastic material. Therefore, due to the elastic deformation of the second valve portion 86, the opening 82a of the in-valve passage 82 is surely closed by the second valve portion 86.
[0089]
(6) The first valve portions 76a and 76b of the second control valve CV2 open and close the first extraction passage 27 at a plurality of locations (in this embodiment, two locations of the end face valve portion 76a and the first peripheral surface valve portion 76b). . Therefore, for example, the first bleed passage 27 is reliably closed by the second control valve CV2, and a reduction in the efficiency of the compressor can be more effectively prevented.
[0090]
In addition, embodiment is not limited to the said embodiment, For example, you may change as follows.
In the above embodiment, the second control valve CV2 is disposed on the air supply passage 29. For example, as shown in FIG. 5, the second through hole 72 b is deleted in the second control valve CV <b> 2 and the first control valve side passage 83 is directly connected to the crank chamber 15. Then, the branch passage 90 branched from the middle of the first control valve side passage 83 is connected to the in-valve passage 82 of the second control valve CV2. In this case, the crank chamber side passage 75 is dedicated to the first extraction passage 27.
[0091]
○ By changing the mode of FIG. 5 and providing grooves or the like in the first valve portions 76a and 76b of the second control valve CV2, the minimum opening of the first valve portions 76a and 76b is set to a non-zero value. The first extraction passage 27 is always open. In this case, the second extraction passage 28 may be deleted. In this way, the passage configuration of the capacity control mechanism can be simplified.
[0092]
5 is changed, and for example, as shown in FIG. 6, the connection position for the second control valve CV2 is switched between the crank chamber side passage 75 and the suction chamber side passage 81, and the first control valve side passage A fixed diaphragm 83 a is provided in the middle part of 83. In this case, if the minimum opening of the first valve portions 76a and 76b is set to a non-zero value, the first bleed passage 27 is always opened, and the second bleed passage 28 is deleted, the prior art (FIG. 8), the present invention (second valve portion 86) is applied to the same configuration.
[0093]
In the above embodiment, the second valve portion 86 of the second control valve CV 2 is formed in a convex shape on the back surface 80 of the spool 76. By changing this, the second valve portion 86 is deleted from the above embodiment, and an elastic coat such as a rubber coat or a resin coat is applied to the back face 80 of the spool 76, thereby making the back face 80 a flat second valve part. You may make it grasp. In addition, as a method other than the elastic coating that causes the back surface 80 of the spool 76 to function as the second valve portion, it is possible to polish the back surface 80 and the end surface 73a of the fitting portion 73 with high accuracy.
[0094]
In the above embodiment, the second control valve CV2 is configured to open and close the air supply passage 29 at a plurality of locations (two locations of the second peripheral surface valve portion 76c and the second valve portion 86). By changing this, the second control valve CV2 is configured to open and close the air supply passage 29 at one location of the second valve portion 86.
[0095]
In the above embodiment, the first valve portions 76a and 76b of the second control valve CV2 are configured to open and close the first bleed passage 27 at a plurality of locations (two locations of the end valve portion 76a and the first circumferential valve portion 76b). there were. This is changed, and the first valve portion of the second control valve CV2 is configured to open and close the first extraction passage 27, for example, at one location of the end surface valve portion 76a or the first circumferential surface valve portion 76b.
[0096]
In the above embodiment, the valve body of the second control valve CV2 is embodied in the spool 76 (cylindrical body). You may change this and use a spherical body as a valve body. In this case, in the sphere, the hemispherical portion on the valve chamber 77 side forms the first valve portion, and the hemispherical portion on the back pressure chamber 78 side forms the back surface and the second valve portion.
[0097]
In the above embodiment, the urging spring 85 is a coil spring, but the urging spring of the present invention is not limited to a coil spring, and may be other springs such as a plate spring and a bar spring.
In the above embodiment, the first control valve CV1 operates to maintain the differential pressure (PdH−PdL) before and after the throttle 36a at a predetermined target value (set differential pressure), thereby changing the discharge capacity of the compressor. It is like that. Further, the first control valve CV1 can change the set differential pressure by external electric control. By changing this, the first control valve operates so as to maintain the pressure in the suction pressure region at a predetermined target value (set suction pressure), and the set suction pressure can be changed by electric control from outside. Change to a suction pressure variable control valve.
[0098]
In the above embodiment, the pressure-sensitive mechanism (pressure-sensitive chamber 48, bellows 50, etc.) is deleted from the first control valve CV1, and the first control valve CV1 is simply a solenoid valve.
In the above embodiment, the solenoid unit 60 is deleted from the first control valve CV1, and the first control valve CV1 is simply a pressure-sensitive valve that does not have an external control function.
[0099]
The present invention may be embodied in a capacity control device used for a wobble type variable capacity compressor.
The technical idea that can be grasped from the above embodiment and other examples will be described.
[0100]
(1) The capacity control mechanism according to claim 3, wherein the second control valve opens and closes the supply passage at a plurality of locations.
(2) The capacity control mechanism according to any one of claims 1 to 4, wherein the first valve portion of the second control valve opens and closes the extraction passage at a plurality of locations.
[0101]
(3) The capacity control mechanism according to any one of claims 1 to 4, or the technical idea (1) or (2), wherein the variable capacity compressor is a clutchless type. The clutchless type variable capacity compressor is a variable capacity compressor that keeps the drive shaft rotating when the refrigeration cycle is stopped while maintaining the minimum inclination angle of the cam plate that does not substantially flow refrigerant into the external refrigerant circuit. It is a type compressor.
[0102]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent the second control valve from malfunctioning due to a decrease in the performance of the first control valve while preventing a decrease in the efficiency of the variable displacement compressor.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a variable displacement swash plate compressor.
FIG. 2 is a cross-sectional view of a first control valve.
FIG. 3 is an enlarged view showing the vicinity of a second control valve in FIG. 1;
FIG. 4 is a cross-sectional view for explaining the operation of a second control valve.
FIG. 5 is an enlarged sectional view showing another example.
FIG. 6 is an enlarged cross-sectional view showing another example.
FIG. 7 is a schematic explanatory diagram of the prior art.
FIG. 8 is a cross-sectional view of the vicinity of a second control valve according to the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 15 ... Crank chamber, 21 ... Suction chamber as suction pressure area, 22 ... Discharge chamber as discharge pressure area, 27 ... First extraction passage as extraction passage, 29 ... Supply passage, 30 ... Refrigerant circulation with compressor An external refrigerant circuit constituting the circuit, 53 ... a valve seat part as a valve opening adjustment position of the first control valve, 76 ... a spool as a valve body (76a ... an end face valve part constituting the first valve part, 76b ... first 1st circumferential surface valve portion constituting the valve portion), 77 ... valve chamber, 78 ... back pressure chamber, 80 ... back surface, 82 ... internal passage (82a ... opening) as an introduction passage, 85 ... biasing spring, 86 ... 2nd valve part, CV1 ... 1st control valve, CV2 ... 2nd control valve.

Claims (4)

The refrigerant circulation circuit of the air conditioner is configured and used in a variable capacity compressor having a configuration in which the discharge capacity is reduced when the crank chamber pressure is increased and the discharge capacity is increased when the crank chamber pressure is decreased. A capacity control mechanism for controlling the discharge capacity of the variable compressor,
A bleed passage connecting the crank chamber and a suction pressure region of the refrigerant circulation circuit;
An air supply passage connecting the crank chamber and a discharge pressure region of the refrigerant circulation circuit;
A first control valve capable of adjusting the opening of the air supply passage;
A back pressure chamber into which a pressure downstream of a valve opening adjustment position of the first control valve in the air supply passage is introduced via an introduction passage; a valve chamber constituting a part of the extraction passage; A first valve portion disposed in the valve chamber and a back surface disposed in the back pressure chamber. When the pressure of the back pressure chamber acting on the back surface increases, the opening degree of the extraction passage is increased by the first valve portion. A capacity control mechanism comprising: a valve body for reducing the valve body; and a second control valve comprising a biasing spring that biases the valve body in a direction in which the first valve portion increases the opening of the extraction passage.
A second valve portion is provided on the back surface of the valve body, and the second valve portion is formed in the back pressure chamber of the introduction passage when the first valve portion sets the extraction passage to a maximum opening. A capacity control mechanism that closes the opening. The second valve portion is convex and tapered toward the opening side of the introduction passage, and the second valve portion can close the opening of the introduction passage by entering the introduction passage. The capacity control mechanism according to claim 1. The capacity control mechanism according to claim 1, wherein the introduction passage and the back pressure chamber constitute a part of the air supply passage. The capacity control mechanism according to any one of claims 1 to 3, wherein the second valve portion is made of an elastic material.

Images