JP2009079530A - Capacity control valve and variable capacity compressor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacity control valve capable of remarkably enlarging an inlet pressure control range, and a variable capacity compressor using the same. <P>SOLUTION: This capacity control valve comprises a valve element for opening and closing a communication path for making at least either of a suction chamber and a discharge chamber of a variable capacity compressor communicate with a crank chamber, a bellows assembly 305 for controlling to open and close the valve element according to the pressure of the suction chamber or the crank chamber by being coupled to the valve element, and a solenoid for applying an electromagnetic force to the valve element. The bellows assembly 305 comprises a bellows 305a and a compression coil spring 305e arranged at the periphery of the bellows 305a so as to energize the bellows 305a in a direction for stretching the bellows 305a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a capacity control valve for 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 Patent Document 1, for example, the capacity control valve includes a bellows as a pressure-sensitive member that receives the pressure of the suction chamber, and in addition to urging the valve body by a solenoid, the suction received by the bellows The valve body is energized according to the chamber pressure, and the discharge volume of the compressor is feedback controlled so that the suction pressure is maintained at a predetermined value by adjusting the flow rate of the working fluid from the discharge chamber to the crank chamber. To do.
JP-A-11-107929

  As described above, the discharge capacity control method that controls the suction pressure is a control method suitable for air-conditioning control, and is widely adopted. In this suction pressure control, for example, in order to reduce the discharge capacity, the suction pressure setting to be controlled may be changed to a high value. In such a case, for example, if the heat load is large and the rotational speed of the compressor is low, the discharge capacity cannot be reduced sufficiently, and if the actual suction pressure exceeds the suction pressure control range, control is completely impossible. There is a problem that becomes.

  The suction pressure control in the variable capacity compressor using R134 as a refrigerant that is currently in practical use has control characteristics (relationship between solenoid current and suction pressure) as shown in FIG. In the capacity control valve having this control characteristic, the upper limit of the suction pressure control range is in the range of 0.3 to 0.4 MPaG. Need to expand.

As a method of expanding the suction pressure control range, the electromagnetic force generated by the solenoid may be increased. However, in order to greatly expand the control range, the solenoid is inevitably increased in size and is not practical.
As another method for expanding the suction pressure control range, it is conceivable to set the pressure sensitive area (effective area) of the bellows for sensing the suction pressure small. However, the reference pressure inside the bellows that opposes the suction pressure across the bellows is vacuum or atmospheric pressure, and it is necessary to place a spring inside, and it is necessary to provide a stopper that regulates the amount of expansion and contraction of the bellows Therefore, there was a limit to downsizing the bellows.

It is also conceivable to use a diaphragm instead of the bellows as a pressure-sensitive member. However, if the diaphragm pressure-sensitive area is set small, the displacement of the diaphragm, that is, the valve stroke must also be reduced due to the life of the diaphragm. Even if a diaphragm was used, there was a limit to downsizing.
The present invention has been made based on the above-described circumstances, and one of its purposes is to provide a capacity control valve capable of greatly expanding the suction pressure control range and a variable capacity compressor using the same.

  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. And a conversion mechanism including a variable swash plate element for converting rotation of the drive shaft into reciprocating motion of the piston, and changing the pressure in the crank chamber to change the stroke of the piston. Is a capacity control valve used in a variable capacity compressor that compresses the refrigerant sucked from the suction chamber into the cylinder bore and discharges it to the discharge chamber, and is at least one of the suction chamber and the discharge chamber A valve body that opens and closes a communication passage that communicates one side with the crank chamber, and a valve body that is connected to the valve body to respond to the pressure in the suction chamber or the crank chamber. A pressure-sensitive device that controls the opening and closing of the valve body, and a solenoid that applies an electromagnetic force to the valve body or the pressure-sensitive device. The pressure-sensitive device is disposed around the bellows and the bellows. A displacement control valve is provided, comprising a compression coil spring that urges in a direction in which the valve is extended.

Preferably, end members having a diameter larger than the outer diameter of the bellows are disposed at both ends of the bellows, and both ends of the compression coil spring are sandwiched between the end members.
Preferably, a guide portion for positioning the compression coil spring is formed on the end member.
Preferably, at least one of the end members sandwiching both ends of the bellows is a sealing member that seals the end of the bellows (Claim 4).

Preferably, one of the end members sandwiching both end portions of the bellows is a positioning member for positioning the pressure sensitive device in a valve housing.
Preferably, the valve body opens and closes a valve hole disposed in a communication passage communicating the discharge chamber and the crank chamber, and the pressure sensing device is disposed in the communication passage on the downstream side of the valve hole. The sealing area of the valve body on which the pressure of the crank chamber defined when the valve body closes the valve hole is set equal to or close to the effective area of the bellows (Claim 6).

  Preferably, a housing having a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore defined therein, a piston disposed in the cylinder bore, a drive shaft rotatably supported in the housing, and the drive shaft And a capacity control valve according to any one of claims 1 to 5, wherein the pressure in the crank chamber is changed. A variable displacement compressor is provided in which the stroke of the piston is adjusted to compress the refrigerant sucked into the cylinder bore from the suction chamber and discharge the refrigerant into the discharge chamber (Claim 7).

In the capacity control valve according to the first aspect of the present invention, the compression coil spring for urging the bellows in the extending direction is arranged not in the bellows but in the periphery, so that the effective area of the bellows can be set small and the suction pressure control range can be set. It can be greatly enlarged.
In addition, the position where the urging force of the compression coil spring acts moves to the outer peripheral side, the falling of the bellows is reduced, and the bellows can be stably contracted and extended in the axial direction. Furthermore, the design freedom of the compression coil spring can be increased.

In the capacity control valve of the second aspect, the compression coil spring arranged around the bellows can be integrated as a bellows assembly, and assembly workability of the capacity control valve can be ensured.
In the capacity control valve according to the third aspect, the displacement of the compression coil spring is eliminated by the guide portion, and the contraction and extension operations of the bellows can be stabilized. In addition, the compression coil spring can be easily attached.

In the capacity control valve according to the fourth aspect, since at least one of the end members sandwiching the both ends of the bellows and the sealing member for sealing the end of the bellows are combined, the number of parts can be reduced and the structure can be simplified. Can be achieved.
In the capacity control valve according to the fifth aspect, since one of the end members sandwiching the both end portions of the bellows and the positioning member for positioning the pressure sensitive device on the valve housing are combined, the number of parts can be reduced and the structure can be simplified. Can be achieved.

In the capacity control valve according to the sixth aspect, as the effective area of the bellows is set to be small, the sealing area of the valve body is also reduced, so that the gas in the discharge chamber excessively flows into the crank chamber by opening the valve body. As a result, the flow rate adjustment of the capacity control valve is stabilized.
In the variable displacement compressor according to the seventh aspect, the minimum piston stroke defined by the minimum inclination angle of the swash plate can be set very small, and the capacity control range can be greatly expanded. Therefore, by the expansion of the suction pressure control range by the capacity control valve The expansion effect of the capacity control range can be sufficiently exhibited.

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 displacement 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.

  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 muffler 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 300 is connected to the rear housing 104, and the capacity control valve 300 is inserted in an air supply passage 125 (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. 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 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 assembly 305 is disposed in the first pressure sensing chamber 302. The bellows assembly 305 is disposed so as to be displaceable in the axial direction of the valve housing 301, and has a function as a pressure sensing device that receives the pressure in the first pressure sensing chamber 302, that is, the crank chamber 105.
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 assembly 305, and has a function of transmitting the displacement of the bellows assembly 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.

FIG. 3 is a structural diagram of the bellows assembly 305.
As shown in FIG. 3, the bellows assembly 305 seals the bellows 305a, an end member 305b sealed at one end of the bellows 305a and welded to the bellows 305a, and the other end of the bellows 305a. The sealing member 305c welded to the bellows 305a, the end member 305d caulked to the sealing member 305c, and the end member 305b and the end member 305d on the outer periphery of the bellows 305a. And a compression coil spring 305e.

The welding of the end member 305b and the sealing member 305c and the bellows 305a is performed in a vacuum, and thus the inside of the bellows 305a is held in a vacuum. The end member 305b, the sealing member 305c, and the bellows 305a are formed of the same material, for example, a copper-based material.
The caulking portion between the sealing member 305c and the end member 305d has a recess formed on the sealing member 305c side, and a part of the end member 305d is plastically deformed into the recess to function as a retaining member. .

One end side 305b1 of the end member 305b is press-fitted and fixed in the hole at the end of the valve housing 301, and the bellows assembly 305 is positioned by adjusting the press-fitting amount. Further, the other end 305b2 of the end member 305b and the tip 305c1 of the sealing member 305c constitute a stopper portion that restricts excessive contraction of the bellows 305a by contacting each other.
Both ends of the compression coil spring 305e are positioned by guide portions 305b3 and 305d1 formed on the end member 305b and the end member 305d, respectively, and are arranged substantially coaxially with the bellows 305a without contacting the outer periphery of the bellows 305a. Yes. The sealing member 305c is formed with a guide portion 305c2 that receives the connecting portion 306.

  In the present embodiment, in particular, the compression coil spring 305e is disposed outside the bellows 305a. For this reason, compared with the prior art in which the compression coil spring 305e is disposed inside the bellows 305a, the position where the urging force acts on the compression coil spring 305e moves to the outer peripheral side, the collapse of the bellows 305a is reduced, and the bellows 305a contracts. The decompression operation is performed stably. In addition, as compared with the case where the compression coil spring 305e is disposed inside the bellows 305a, space constraints are reduced, and the design freedom of the compression coil spring 305e is increased.

Hereinafter, control characteristics of the displacement control valve 300 will be described.
The force acting on the valve body 304 of the capacity control valve 300 includes, in addition to the electromagnetic force F (I) generated by the solenoid 314, the urging force fs generated by the forced release spring 311, the force generated 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 compression coil spring 305e. When the effective pressure receiving area of the bellows 305a 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.

  In the present embodiment, the relationship of Sb = Sv = Sr is established. Further, the electromagnetic force F (I) is designed to be substantially proportional to the control current I. When F (I) = AI (A is a coefficient), the equation (1) is expressed by the following equation (2): It becomes. Then, when the expression (2) is modified to obtain the suction pressure Ps, the following expression (3) is obtained.

Therefore, as shown in Expression (3), the suction pressure Ps is uniquely determined by the control current I, and has a control characteristic in which the suction pressure Ps decreases as the control current I increases.
FIG. 4 is a graph showing the relationship between the control current I and the suction pressure Ps.
FIG. 4 shows that in the present embodiment, for example, when the control current Ia is used, the suction pressure Psa is obtained. As described above, since there is no compression coil spring 305e in the inner space of the bellows 305a, the bellows 305a can be reduced in size (smaller diameter). Thereby, the bellows effective area Sb can be set small. Therefore, as shown in FIG. 4, the control range (minimum value PsL to maximum value PsH ′) of the suction pressure Ps in the control current range defined by the maximum value Imax and the minimum value Imin of the control current I is set to the inside of the bellows 305a. The space can be expanded in comparison with the control range (minimum value PsL to maximum value PsH) of the suction pressure Ps in the conventional capacity control valve in which the compression coil spring 305e is disposed.

  Further, since the effective area Sb of the bellows 305a and the valve body seal area Sv are set to be equal to each other, the valve body seal area Sv (valve hole area) also decreases as the bellows effective area Sb is set smaller. As a result, the gas in the discharge chamber 120 is prevented from flowing excessively into the crank chamber 105 by opening the valve body 304, and the flow rate adjustment of the capacity control valve 300 is stabilized.

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 control current I of the solenoid 314 set to the maximum value Imax, the suction pressure Ps is higher than the predetermined value Psimax immediately after the start, and the bellows 305 contracts and separates from the connecting portion 306, and the solenoid Energized by the electromagnetic force 314, 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 ΔP, the inclination angle of the swash plate 107 decreases and the discharge capacity decreases.

  When the discharge capacity decreases and the suction pressure Ps increases, the bellows assembly 305 contracts and the valve body 304 moves in a direction to close 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 ΔP, 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 the predetermined suction pressure Psa, and the discharge capacity is controlled.

Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a structural diagram of a bellows assembly 405 according to the second embodiment. In addition, about the structure same as the bellows assembly 305 of 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.
The bellows assembly 405 of the second embodiment is different from the bellows assembly 305 of the first embodiment in the structure of the stopper portion. Specifically, the outer peripheral end portion of the end member 405d corresponding to the end member 305d of the first embodiment extends in a cylindrical shape toward the end member 405b so as to cover the compression coil spring 305e. And the front-end | tip 405d1 contact | abuts to the edge part member 405b, and the stopper part which regulates the excessive shrinkage | contraction of the bellows 305a is comprised. Accordingly, it is not necessary to extend the sealing member 405c and the end member 405b into the bellows 305a, and the inner diameter of the bellows 305a can be further reduced. Therefore, the effective area Sb of the bellows 305a can be set smaller, and the control range of the suction pressure Ps can be further expanded.

  The end member 405b is provided with a communication hole 406 that allows the space in the bellows 305a to communicate with the outside. With such a structure, the inside of the bellows 305a need not be evacuated, and the manufacturability of the bellows assembly 405 can be significantly improved. As described above, when the pressure inside the bellows 305a is set to atmospheric pressure, the force of atmospheric pressure acts in the valve opening direction as compared with the case where a vacuum is applied. Therefore, the biasing force Fb is set to be small and corrected.

In addition, this invention is not limited to 1st Embodiment mentioned above, A various deformation | transformation is possible.
For example, in the above embodiment, the end members 305d and 405d and the sealing members 305c and 405c may be fixed by press-fitting, welding, or screw fitting, or the end members 305d and 405d are sealed. The members 305c and 405c may be integrally formed. Further, the guide portions 305b3 and 305d1 may have a groove shape. The guide portions 305c2 and 405c2 with which the connecting portion 306 abuts may be formed of a high hardness member that is separate from the sealing members 305c and 405c.

  In addition, the present invention corresponds to a capacity control valve of any structure that operates in response to the suction pressure Ps or the crank pressure Pc in which the compression coil spring 305e is disposed outside the bellows 305a. A capacity control valve that opens and closes the bleed passage 127, a capacity control valve that increases the control suction pressure when the control current I increases, a capacity control valve that has a suction pressure control characteristic affected by the discharge pressure Pd, Alternatively, the present invention can be applied to a capacity control valve without the forced release spring 311.

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 sectional drawing which shows the structure of the bellows assembly of 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 bellows assembly of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Compressor 300 Capacity control valve 304 Valve body 305 Bellows assembly 305a Bellows 314 Solenoid 305e Compression coil spring 305b, 305d, 405b, 405d End member 305d1, 305b3 Guide part 305c Sealing member

Claims (7)

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 And a conversion mechanism including a variable swash plate element that converts the reciprocating motion of the piston, and the stroke of the piston is adjusted by changing the pressure of the crank chamber, and the cylinder bore is sucked from the suction chamber. A capacity control valve used in a variable capacity compressor that compresses and discharges refrigerant into the discharge chamber,
A valve body that opens and closes a communication passage that communicates at least one of the suction chamber and the discharge chamber with the crank chamber, and the valve body is connected to the valve body according to the pressure in the suction chamber or the crank chamber. A pressure-sensitive device that controls opening and closing of the valve body, and a solenoid that applies an electromagnetic force to the valve body or the pressure-sensitive device,
The pressure-sensitive device includes a bellows and a compression coil spring that is disposed around the bellows and biases the bellows in a direction in which the bellows extends.   2. The capacity according to claim 1, wherein end members having a diameter larger than an outer diameter of the bellows are disposed at both ends of the bellows, and both ends of the compression coil spring are sandwiched between the end members. Control valve.   The capacity control valve according to claim 2, wherein a guide portion for positioning the compression coil spring is formed on the end member.   4. The capacity control valve according to claim 2, wherein at least one of the end members sandwiching both ends of the bellows is a sealing member that seals the end of the bellows.   5. The capacity control valve according to claim 2, wherein one of the end members sandwiching both ends of the bellows is a positioning member that positions the pressure-sensitive device in a valve housing. .   The valve body opens and closes a valve hole disposed in a communication passage communicating the discharge chamber and the crank chamber, and the pressure sensitive device is disposed in the communication passage on the downstream side of the valve hole, The seal area of the valve body on which the pressure of the crank chamber, which is defined when the body closes the valve hole, is set equal to or close to the effective area of the bellows. The capacity control valve according to any one of 1 to 5.   A housing having a discharge chamber, a suction chamber, a crank chamber, and a cylinder bore defined therein, 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 piston into reciprocating motion, and a capacity control valve according to any one of claims 1 to 6, wherein the piston is changed by changing the pressure in the crank chamber. The variable capacity compressor is characterized in that the refrigerant sucked from the suction chamber into the cylinder bore is compressed and discharged into the discharge chamber.

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