JP2009057855A - Variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement compressor having a capacity control valve for restraining generation of self-excited vibration of a valve element at a very small amount of flow. <P>SOLUTION: The capacity control valve 300 of the variable displacement compressor has a valve chest 303 communicating with a delivery chamber, a valve hole 301c having one end communicating with the valve chest 303 and having the other end communicating with a crankcase, the valve element 304 receiving pressure of the crankcase by forming a seal surface for opening-closing the valve hole 301c on one end side and receiving pressure of a suction chamber by communicating the other end side with the suction chamber, and bellows 305 displaced in response to the pressure of the crank chamber and connected to the one end side of the valve element 304. The effective pressure receiving area Sb of the bellows 305 is set larger than the seal area Sv of the seal surface for receiving the pressure of the crankcase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable capacity compressor used in a vehicle air conditioner system.

  For example, a reciprocating variable displacement compressor used in a vehicle air conditioner system includes a housing, and a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore are defined in the housing. A swash plate is tiltably connected to a drive shaft extending in the crank chamber, and a conversion mechanism including the swash plate converts the rotation of the drive shaft into a reciprocating motion of a piston disposed in the cylinder bore. The reciprocating motion of the piston performs the steps of sucking the working fluid from the suction chamber into the cylinder bore, compressing the sucked working fluid, and discharging the compressed working fluid into the discharge chamber.

The stroke length of the piston, that is, the discharge capacity of the compressor is variable by changing the pressure (control pressure) in the crank chamber. In order to control the discharge capacity, a capacity control valve is disposed in the air supply passage that communicates the discharge chamber and the crank chamber, and a throttle is disposed in the bleed passage that communicates the crank chamber and the suction chamber. .
As described in, for example, Patent Document 1, the capacity control valve introduces the pressure of the suction chamber, opens and closes the valve body by the difference between the pressure of the suction chamber and the pressure of the crank chamber, and from the discharge chamber to the crank chamber The discharge capacity of the compressor is changed by supplying and controlling the working fluid. The capacity control valve further includes a bellows as a pressure-sensitive member that receives the pressure in the crank chamber, and urges the valve body in the valve closing direction by the pressure in the crank chamber received by the bellows, so that the discharge capacity of the compressor Is mechanically feedback controlled.
JP 2003-254246 A

The effective pressure-receiving area of the pressure-sensitive member represents the sensitivity to the pressure received by the pressure-sensitive member. When the effective pressure-receiving area increases, the pressure-sensitive member responds sensitively to pressure changes, while when the effective pressure-receiving area decreases, the pressure changes. The sensitivity to becomes dull. Since this affects the control stability of the valve body, an appropriate effective pressure receiving area is set in consideration of this point.
Since the capacity control valve disclosed in Patent Document 1 uses a pressure-sensitive member having an appropriate effective pressure-receiving area as described above, the effective pressure-receiving area of the pressure-sensitive member and the seal area of the valve body are the same size. Therefore, the sealing area of the valve body is greatly increased as compared with a normal control valve. The capacity control valve is disposed in an air supply passage that connects the discharge chamber and the crank chamber, and a discharge pressure acts on the upstream side of the valve body, while a crank pressure acts on the downstream side of the valve body. That is, the pressure difference is large between the upstream and downstream of the valve body, and the seal area of the valve body is large, so that the flow rate change with respect to the opening degree change of the valve body is large.

With such a capacity control valve, there is no problem when the flow rate is large, but it is difficult to adjust the opening of the valve body when the flow rate is very small, and the valve body repeatedly contacts and separates from the valve seat. Vibration is likely to occur. As a result, there is a problem that vibration and noise due to the capacity control valve are likely to occur and wear of the valve seat increases.
The present invention has been made based on the above-described circumstances, and one of its purposes is to provide a capacity control valve of a variable capacity compressor that suppresses the occurrence of self-excited vibration of a valve body at a minute flow rate. .

  In order to achieve the above object, according to the present invention, a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore are defined in the interior, a piston disposed in the cylinder bore, and rotatable in the housing. A drive shaft supported by the shaft, a conversion mechanism including a variable inclination swash plate element that converts rotation of the drive shaft into reciprocating motion of the piston, and a first communication path that communicates the discharge chamber and the crank chamber. A capacity control valve that opens and closes, and a throttle element that is disposed in a second communication path that connects the crank chamber and the suction chamber, and changes the pressure of the crank chamber by adjusting the opening of the capacity control valve, In the variable capacity compressor that adjusts the stroke of the piston to compress the refrigerant sucked into the cylinder bore from the suction chamber and discharges the refrigerant to the discharge chamber, the capacity control valve includes the discharge chamber A valve chamber that communicates with the valve chamber, one end that communicates with the valve chamber, the other end that communicates with the crank chamber, and a seal surface that opens and closes the valve hole is formed on one end side to receive the pressure in the crank chamber A valve body whose other end is communicated with the suction chamber and receives the pressure of the suction chamber, a pressure sensing member that is displaced in response to the pressure of the crank chamber, and is connected to one end of the valve body; An effective pressure receiving area of the pressure-sensitive member is set larger than a seal area of the seal surface that receives the pressure of the crank chamber. 1).

Preferably, the effective pressure-receiving area of the pressure-sensitive member includes: a seal area of the seal surface that receives the pressure of the crank chamber; and a pressure-receiving area of the pressure-receiving surface on the other end side of the valve body that receives the pressure of the suction chamber. Is set to be equal to or less than the total area (claim 2).
Preferably, the pressure-sensitive member receives the pressure of the first communication passage downstream from the valve hole (Claim 3).

In the variable capacity compressor according to the first aspect of the present invention, the effective pressure receiving area of the pressure-sensitive member is set larger than the seal area of the seal surface that receives the pressure of the crank chamber, so the pressure in the crank chamber closes the valve body. Acts on direction. Therefore, it is possible to suppress the valve body from opening excessively and to suppress the occurrence of self-excited vibration of the valve body.
In the variable capacity compressor according to the second aspect, since the amount of change in the pressure in the crank chamber is larger than the amount of change in the pressure in the suction chamber, the accuracy of the suction pressure control can be ensured.

  In the variable capacity compressor according to the third aspect, since the pressure sensitive member reacts quickly to the pressure increase at the time of opening the valve and acts on the valve body in the closing direction, it is possible to quickly suppress the self-excited vibration of the valve body.

FIG. 1 is a diagram showing a schematic configuration of a refrigeration cycle of a vehicle air conditioning system together with a longitudinal section of a variable capacity compressor.
As shown in FIG. 1, the refrigeration cycle 10 of the vehicle air conditioning system includes a circulation path 12 through which a refrigerant (for example, R134a) as a working fluid circulates. In the circulation path 12, a variable capacity compressor (hereinafter simply referred to as a compressor 100), a radiator (condenser) 14, an expander (expansion valve) 16, and an evaporator 18 are inserted in order in the refrigerant flow direction. Has been. The compressor 100 performs a series of processes including a refrigerant suction process, a suction refrigerant compression process, and a compressed refrigerant discharge process to circulate the refrigerant in the circulation path 12.

The evaporator 18 also constitutes a part of the air circuit of the vehicle air conditioning system, and the air flow that passes through the evaporator 18 is cooled by removing the heat of vaporization by the refrigerant in the evaporator 18.
The compressor 100 is a swash plate type variable capacity compressor, and includes a cylinder block 101 having a plurality of cylinder bores 101a, a front housing 102 connected to one end of the cylinder block 101, and a valve plate at the other end of the cylinder block 101. And a rear housing 104 connected to each other through 103.

  A crank chamber 105 is defined by the cylinder block 101 and the front housing 102, and the drive shaft 106 extends vertically through the crank chamber 105. The drive shaft 106 passes through an annular swash plate 107 disposed in the crank chamber 105, and the swash plate 107 is hinged to a rotor 108 fixed to the drive shaft 106 via a connecting portion 109. Accordingly, the swash plate 107 can tilt while moving along the drive shaft 106.

Between the rotor 108 and the swash plate 107, a coil spring 110 that urges the swash plate 107 toward the minimum inclination angle is mounted around the drive shaft 106, while the coil spring 110 is sandwiched between the rotor 108 and the swash plate 107. On the opposite side, that is, between the swash plate 107 and the cylinder block 101, a coil spring 111 that biases the swash plate 107 toward the maximum inclination angle is mounted around the drive shaft 106.
The drive shaft 106 passes through the boss portion 102a protruding to the outside of the front housing 102, and its tip extends to the outside. A shaft seal device 112 is inserted between the drive shaft 106 and the boss portion 102a to block the inside and the outside of the front housing 102 from each other. The drive shaft 106 is rotatably supported by bearings 113, 114, 115, and 116 in the radial direction and the thrust direction. The drive shaft 106 is rotationally driven by a driving force transmitted from an external drive source such as an engine to the tip protruding from the boss portion 102a.

  A piston 117 is disposed in the cylinder bore 101a, and a tail portion protruding into the crank chamber 105 is formed integrally with the piston 117. A pair of shoes 118 is disposed in a recess 117a formed in the tail portion, and the shoes 118 are in sliding contact with the outer peripheral portion of the swash plate 107 so as to be sandwiched therebetween. Therefore, the piston 117 and the swash plate 107 are interlocked with each other via the shoe 118, and the piston 117 reciprocates in the cylinder bore 101a by the rotation of the drive shaft 106 (conversion mechanism).

  A suction chamber 119 and a discharge chamber 120 are defined in the rear housing 104, and the suction chamber 119 can communicate with the cylinder bore 101 a through a suction hole 103 a provided in the valve plate 103. The discharge chamber 120 communicates with the cylinder bore 101a through a discharge hole 103b provided in the valve plate 103. The suction hole 103a and the discharge hole 103b are opened and closed by a suction valve and a discharge valve (not shown), respectively.

  A muffler 121 is provided outside the cylinder block 101. A muffler casing 122 constituting the muff et al. 121 is joined to a muffler base 101b formed integrally with the cylinder block 101 via a seal member (not shown). The muffler casing 122 and the muffler base 101b define a muffler space 123. The muffler space 123 communicates with the discharge chamber 120 via a discharge passage 124 that passes through the rear housing 104, the valve plate 103, and the muffler base 101b.

  A discharge port 122a is formed in the muffler casing 122, and a check valve 200 is disposed in the muffler space 123 so as to block between the discharge passage 124 and the discharge port 122a. Specifically, the check valve 200 opens and closes according to the pressure difference between the pressure on the discharge passage 124 side and the pressure on the muffler space 123 side, and closes when the pressure difference is smaller than a predetermined value. If larger, open.

The discharge chamber 120 can communicate with the forward portion of the circulation path 12 through the discharge passage 124, the muffler space 123, and the discharge port 122 a, and this communication is interrupted by the check valve 200. On the other hand, the suction chamber 119 communicates with the return path portion of the circulation path 12 via a suction port 104 a provided in the rear housing 104.
A capacity control valve (electromagnetic control valve) 300 is connected to the rear housing 104, and the capacity control valve 300 is inserted in the air supply passage 125 (first communication passage). A part of the air supply passage 125 extends from the rear housing 104 to the cylinder block 101 through the valve plate 103 so as to communicate between the discharge chamber 120 and the crank chamber 105.

On the other hand, the suction chamber 119 communicates with the crank chamber 105 via the extraction passage 127 (second communication passage). The extraction passage 127 includes a clearance between the drive shaft 106 and the bearings 115 and 116, a space 128, and a fixed orifice 103 c (throttle element) formed in the valve plate 103.
The suction chamber 119 is connected to the capacity control valve 300 independently of the air supply passage 125 through a pressure sensitive passage 126 formed in the rear housing 104.

FIG. 2 is a cross-sectional view showing the structure of the capacity control valve 300 according to the first embodiment of the present invention.
As shown in FIG. 2, the capacity control valve 300 includes a valve unit and a drive unit that opens and closes the valve unit. The valve unit includes a cylindrical valve housing 301, in which a first pressure sensing chamber 302, a valve chamber 303, and a second pressure sensing chamber 307 are formed in order in the axial direction. The first pressure sensing chamber 302 communicates with the crank chamber 105 through a communication hole 301 a formed in the outer peripheral surface of the valve housing 301 and a downstream portion of the air supply passage 125. The second pressure sensing chamber 307 communicates with the suction chamber 119 via a communication hole 301 e formed on the outer peripheral surface of the valve housing 301 and a pressure sensing passage 126. The valve chamber 303 communicates with the discharge chamber 120 via a communication hole 301 b formed in the outer peripheral surface of the valve housing 301 and an upstream portion of the air supply passage 125. The first pressure sensing chamber 302 and the valve chamber 303 can communicate with each other through a valve hole 301c. A support hole 301 d is formed between the valve chamber 303 and the second pressure sensing chamber 307.

A bellows 305 is disposed in the first pressure sensing chamber 302. The bellows 305 has a built-in spring and has a built-in spring. The bellows 305 is disposed so as to be displaceable in the axial direction of the valve housing 301. It has a function.
A cylindrical valve body 304 is accommodated in the valve chamber 303. The valve body 304 can slide in the support hole 301 d while the outer peripheral surface is in close contact with the inner peripheral surface of the support hole 301 d, and can move in the axial direction of the valve housing 301. One end of the valve body 304 can open and close the valve hole 301 c, and the other end protrudes into the second pressure sensing chamber 307.

One end of a rod-shaped connecting portion 306 is fixed to one end of the valve body 304. The other end of the connecting portion 306 is disposed so as to be able to contact the bellows 305 and has a function of transmitting the displacement of the bellows 305 to the valve body 304.
The drive unit has a cylindrical solenoid housing 312 that is coaxially connected to the other end of the valve housing 301. A solenoid 314 is accommodated in the solenoid housing 312. A concentric cylindrical fixed core 310 is accommodated in the solenoid housing 312, and the fixed core 310 extends from the valve housing 301 to the center of the solenoid 314. The end of the fixed core 310 on the side opposite to the valve housing 301 is surrounded and closed by a cylindrical sleeve 313.

The fixed core 310 has an insertion hole 310 a in the center, and one end of the insertion hole 310 a opens into the second pressure sensing chamber 307. A cylindrical movable core 308 is accommodated between the fixed core 310 and the closed end of the sleeve 313.
A solenoid rod 309 is inserted into the insertion hole 310a, and one end of the solenoid rod 309 is press-fitted and fixed coaxially to the valve body 304. The other end of the solenoid rod 309 is fitted into a through-hole formed in the movable core 308, and the solenoid rod 309 and the movable core 308 are integrated. A forced release spring 311 is provided between the fixed core 310 and the movable core 308 to urge the movable core 308 in a direction away from the fixed core 310 (valve opening direction).

The movable core 308, the fixed core 310, and the solenoid housing 312 are formed of a magnetic material and constitute a magnetic circuit. The sleeve 313 is made of a non-magnetic stainless steel material.
A control device 400 provided outside the compressor 100 is connected to the solenoid 314. When the control current I is supplied from the control device 400, the solenoid 314 generates an electromagnetic force F (I). The electromagnetic force F (I) of the solenoid 314 attracts the movable core 308 toward the fixed core 310 and acts on the valve body 304 in the valve closing direction.

  The force acting on the valve body 304 of the displacement control valve 300 includes, in addition to the electromagnetic force F (I) by the solenoid 314, the urging force fs by the forcible release spring 311, the force by the pressure in the valve chamber 303 (discharge pressure Pd), These are the force due to the pressure in the first pressure sensing chamber 302 (crank pressure Pc), the force due to the pressure in the second pressure sensing chamber 307 (suction pressure Ps), and the biasing force Fb due to the spring built in the bellows 305. When the effective pressure receiving area of the bellows 305 is Sb, the seal area Sv that is the area of the valve hole 301c shielded by the valve body 304, and the cross-sectional area Sr of the cylindrical outer peripheral surface of the valve body 304, Indicated. In equation (1), + indicates the valve closing direction of the valve body 304, and-indicates the valve opening direction. Then, when formula (1) is modified to obtain crank pressure Pc, formula (2) is obtained.

  In the present embodiment, in particular, the relationship Sb> Sv = Sr is established. Since Sv = Sr, equation (2) becomes equation (3).

  As shown in Expression (3), the discharge pressure Pd does not act in the opening / closing direction of the valve body 304. In addition, since Sb> Sv, the crank pressure Pc acts in the direction of closing the valve body 304, and increases when the suction pressure Ps decreases, and decreases when the suction pressure Ps increases. The inclination is determined by Sv / (Sb−Sv), and it is found that the inclination increases as Sv approaches Sb. Therefore, the smaller the difference between Sv and Sb, the more sensitive the crank pressure Pc is to the change in the suction pressure Ps, and the smaller the difference between Sv and Sb, the less sensitive the change in the suction pressure Ps. That is, Sv / (Sb−Sv) represents the sensitivity to the amount of change in the suction pressure Ps. Here, when Sv / (Sb−Sv) = 1, that is, when Sv = Sb / 2 is set, the change amount of the crank pressure Pc with respect to the change amount of the suction pressure Ps becomes equal. Further, when Sv / (Sb−Sv)> 1 is set, the change amount of the crank pressure Pc with respect to the change amount of the suction pressure Ps increases, whereas when Sv / (Sb−Sv) <1, the suction pressure is increased. The change amount of the crank pressure Pc with respect to the change amount of Ps decreases. Therefore, in order to control the suction pressure Ps with high accuracy, it is desirable to set Sv / (Sb−Sv) ≧ 1.

  The second term on the right side of the equation (3) indicates the electromagnetic force generated by the solenoid 314, and indicates that the crank pressure Pc decreases when the control current I of the solenoid 314 is increased. The third term on the right side of Equation (3) is a constant term. Here, if the control current I is constant, the second term on the right side of the equation (3) can also be regarded as a constant term. In this case, it is found that the crank pressure Pc is a linear function of the suction pressure Ps. .

FIG. 3 is a graph showing the relationship between the suction pressure Ps and the crank pressure Pc. FIG. 4 is a graph showing the relationship between the control current I and the suction pressure Ps.
Assuming that the constant term changes when the control current I is changed, as shown in FIG. 3, Equation (3) shows that the crank pressure Pc increases when the suction pressure Ps decreases, while the crank pressure Pc increases when the suction pressure Ps increases. It can be considered that the characteristic that the voltage decreases decreases between the upper limit value Imax and the lower limit value Imin of the control current I due to the change of the control current I.

Therefore, in the compressor 100 that controls the discharge capacity according to the pressure difference ΔP between the crank pressure Pc and the suction pressure Ps, the suction pressure Ps can be changed and controlled according to the control current I as shown in FIG.
Next, the control operation of the compressor 100 using the capacity control valve 300 will be described.
For example, when the variable capacity compressor 100 is started with the solenoid control current set to the maximum value Imax, the suction pressure Ps is higher than the predetermined value Psimax immediately after the start, the bellows 305 contracts and separates from the connecting portion 306, and the solenoid 314 Energized by electromagnetic force, the valve body 304 comes into contact with the valve seat and closes the valve hole 301c.

  Accordingly, the discharge gas (refrigerant) is not introduced into the crank chamber 105, and only blow-by gas generated when the piston 117 compresses the suction refrigerant flows from the crank chamber 105 to the suction chamber 119 via the extraction passage 127. The flow passage area of the fixed orifice 103c is set to the minimum flow passage area necessary for flowing blow-by gas to the suction chamber 119, and the gas in the crank chamber 105 is quickly discharged to the suction chamber 119. The pressure Pc quickly decreases and becomes substantially equal to the suction pressure Ps, the inclination angle of the swash plate 107 increases, and the compressor 100 is maintained at the maximum capacity.

  When the compressor 100 is operated at the maximum capacity and the suction pressure Ps gradually decreases to a predetermined value Psimax set by the capacity control valve 300, the bellows 305 expands and connects to the connecting portion 306, and the valve body 304 is The valve hole 301c is opened by moving. Therefore, the discharge chamber 120 and the crank chamber 105 communicate with each other via the air supply passage 125, and the discharge gas is introduced into the crank chamber 105. Since the amount of outflow from the crank chamber 105 to the suction chamber 119 is limited by the fixed orifice 103c, the crank pressure Pc rises due to the inflow of the discharge gas into the crank chamber 105. When the pressure difference between the crank pressure Pc and the suction pressure Ps increases to a predetermined value ΔPH, the inclination angle of the swash plate 107 decreases and the discharge capacity decreases.

  In the present embodiment, since Sb> Sv is set and the crank pressure Pc acts in the direction of closing the valve body 304, the degree of increase (sensitivity) of the crank pressure Pc is Sv / (Sb−Sv) in the equation (3). It is suppressed as shown by. Therefore, in the present embodiment, the valve opening is reduced to the extent that the crank pressure Pc acts compared to the conventional capacity control valve in which the influence of the crank pressure Pc is eliminated.

  Thereafter, when the discharge capacity decreases and the suction pressure Ps increases, the bellows 305 contracts and the valve body 304 moves in the direction of closing the valve hole 301c, so that the amount of discharge gas introduced into the crank chamber 105 decreases. The crank pressure Pc decreases. When the pressure difference between the crank pressure Pc and the suction pressure Ps decreases to a predetermined value ΔPL (ΔPL <ΔPH), the inclination angle of the swash plate 107 increases and the discharge capacity increases. By such an operation, the opening degree of the valve body 304 is adjusted so as to maintain a predetermined suction pressure Psimax, and the discharge capacity is controlled. In the above description, the average value of the predetermined values ΔPH and ΔPL is simply regarded as the pressure difference ΔP.

  As described above, in the present embodiment, Sb> Sv, that is, the effective pressure receiving area Sb of the bellows 305 is set larger than the seal area Sv that is the area for receiving the crank pressure Pc. Even when a large amount of discharge gas is introduced into the crank chamber 105 when the valve body 304 is opened, a force in the closing direction is applied to the valve body 304 by the bellows 305, and the valve body 304 becomes excessive. Can be prevented from opening. Thereby, the valve body 304 can be stably operated in a region where the opening degree of the valve body 304 is small, and self-excited vibration of the valve body can be prevented. Further, since the bellows 305 is disposed immediately after the valve body 304, the bellows 305 reacts quickly with the pressure increase in the first pressure sensing chamber 302 and acts on the valve body 304 in a closing direction. Excited vibration can be prevented quickly.

Further, if Sr / (Sb−Sv) ≧ 1 is set, that is, if Sb ≦ Sv + Sr and the effective pressure receiving area Sb of the bellows 305 is set to be equal to or less than the total area of the seal area Sv of the valve body and the cross-sectional area Sr, suction is performed. Since the change amount of the crank pressure Pc with respect to the change amount of the pressure Ps is ensured to be relatively large, it is possible to ensure the control accuracy of the suction pressure Ps while preventing the self-excited vibration of the valve body 304.
The present invention is not limited to the first embodiment described above, and various modifications are possible.

FIG. 5 shows a partial structure of a capacity control valve 500 according to the second embodiment. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
The capacity control valve 500 of the second embodiment is a mechanical capacity control valve without a solenoid. The capacity control valve 500 includes a lid member 501 that partitions the second pressure sensing chamber 307 together with the valve housing 301, and a forced pressing spring 502 is provided between the lid member 501 and the valve body 304. The forced pressing spring 502 biases the valve body 304 in the valve closing direction.

  The force acting on the valve body 304 in the present embodiment is expressed by Expression (4). When this is deformed to obtain the crank pressure Pc, Expression (5) is obtained. In the equations (4) and (5), fs indicates the urging force by the forced pressing spring 502.

  In this embodiment, since there is no solenoid, it differs from the expressions (1) and (2) in the first embodiment in that there is no term relating to the control current I. However, also in this embodiment, if Sb> Sv is set, the valve body 304 can be stably operated in a region where the opening degree of the valve body 304 is small, as in the first embodiment. Self-excited vibration can be prevented.

In the first and second embodiments described above, Sv> Sr or Sv <Sr may be set. When Sv> Sr is set, the discharge pressure Pd acts in the valve closing direction, while when Sv <Sr is set, the discharge pressure Pd acts in the valve opening direction. Therefore, the characteristics of the capacity control valve can be changed by appropriately setting these.
In addition, the present application is not limited to disposing the first pressure sensing chamber 302 in the air supply passage 125, but may be configured such that the pressure of the crank chamber 105 is introduced into the first pressure sensing chamber 302. The pressure-sensitive member that receives the pressure in the first pressure-sensitive chamber 302 is not limited to using the bellows 305, and for example, a diaphragm may be used. Further, the control suction pressure may be increased as the control current I increases.

As the compressor 100, a variable capacity compressor equipped with an electromagnetic clutch, a clutchless variable capacity compressor, or a swing plate type variable capacity compressor may be used. Alternatively, the present invention can be applied to a variable capacity compressor driven by a motor and a variable capacity compressor provided with a variable flow rate throttle or a throttle that is controlled to open and close by a valve body as a throttle element of the extraction passage 127.
Moreover, as a refrigerant | coolant, it is not limited to R134a, You may use a carbon dioxide and another new refrigerant | coolant.

It is a figure which shows schematic structure of the refrigerating cycle of a vehicle air conditioning system with the longitudinal cross-section of a variable capacity compressor. It is sectional drawing which shows the structure of the capacity | capacitance control valve of 1st Embodiment. It is a graph which shows the relationship between the suction pressure and crank pressure in 1st Embodiment. It is a graph which shows the relationship between the control current and suction pressure in 1st Embodiment. It is sectional drawing which shows the structure of the capacity | capacitance control valve of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Compressor 101 Cylinder block 106 Drive shaft 107 Swash plate 116 Fixed orifice 117 Piston 300 Capacity control valve 301a Valve hole 304 Valve body 305 Bellows

Claims (3)

A housing in which a discharge chamber, a suction chamber, a crank chamber and a cylinder bore are defined, a piston disposed in the cylinder bore, a drive shaft rotatably supported in the housing, and rotation of the drive shaft A conversion mechanism including a variable swash plate element that converts the reciprocating motion of the piston; a capacity control valve that opens and closes a first communication path that connects the discharge chamber and the crank chamber; the crank chamber and the suction chamber; And a throttle element disposed in a second communication path that communicates with each other, changes the pressure of the crank chamber by adjusting the opening of the capacity control valve, adjusts the stroke of the piston, and moves from the suction chamber to the cylinder bore. In the variable capacity compressor that compresses the sucked refrigerant and discharges it to the discharge chamber,
The capacity control valve has a valve chamber communicating with the discharge chamber, a valve hole having one end communicating with the valve chamber, the other end communicating with the crank chamber, and a seal surface for opening and closing the valve hole on one end side. A valve body formed to receive the pressure of the crank chamber, the other end communicating with the suction chamber and receiving the pressure of the suction chamber, and displaced in response to the pressure of the crank chamber, A pressure-sensitive member connected to one end side,
An effective pressure receiving area of the pressure-sensitive member is set to be larger than a seal area of the seal surface that receives the pressure of the crank chamber.   The effective pressure-receiving area of the pressure-sensitive member is the total area of the seal area of the seal surface that receives the pressure of the crank chamber and the pressure-receiving area of the pressure-receiving surface on the other end side of the valve body that receives the pressure of the suction chamber. The variable capacity compressor according to claim 1, wherein the variable capacity compressor is set as follows.   3. The variable capacity compressor according to claim 1, wherein the pressure-sensitive member receives pressure of the first communication passage downstream from the valve hole.

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