Patent Publication Number: US-2022213878-A1

Title: Capacity control valve

Description:
TECHNICAL FIELD 
     The present invention relates to a capacity control valve that variably controls capacity of a working fluid, for example, a capacity control valve that controls a discharge amount of a variable displacement compressor used for an air conditioning system of an automobile in accordance with pressure. 
     BACKGROUND ART 
     A variable displacement compressor used for an air conditioning system of an automobile, etc. includes a rotating shaft to be driven and rotated by an engine, a swash plate coupled to the rotating shaft in such a manner that a tilt angle is variable, compressing pistons coupled to the swash plate, etc., and by changing the tilt angle of the swash plate, changes a stroke amount of the pistons to control a discharge amount of a fluid. This tilt angle of the swash plate can be continuously changed by appropriately controlling pressure in a control chamber while utilizing suction pressure Ps of a suction chamber that suctions the fluid, discharge pressure Pd of a discharge chamber that discharges the fluid pressurized by the pistons, and control pressure Pc of the control chamber that houses the swash plate, with using a capacity control valve to be driven to open and close by electromagnetic force. 
     At the time of continuously driving the variable displacement compressor, the capacity control valve performs normal control in which energization is controlled by a control computer, a valve element is moved in the axial direction by electromagnetic force generated in a solenoid, and a CS valve provided between a control port through which a control fluid of the control pressure Pc passes and a suction port through which a suction fluid of the suction pressure Ps passes is opened and closed to adjust the control pressure Pc of the control chamber of the variable displacement compressor. 
     For example, a capacity control valve shown in Patent Citation 1 mainly includes a valve housing that includes a Pc port through which a control fluid passes and a Ps port through which a suction fluid passes and a CS valve that is able to switch a communication state of the Pc port and the Ps port and adjusts a control pressure Pc by opening and closing the CS valve. The CS valve includes a CS valve element that is axially driven by a solenoid and a CS valve seat that is provided between the Pc port and the Ps port and is able to contact the CS valve element and is configured to increase the control pressure Pc by closing the CS valve and decrease the control pressure Pc by opening the CS valve. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Citation 1: JP 3581598 B2 (PAGE 4, FIG. 8) 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the capacity control valve of Patent Citation 1, since the Pc port is disposed in the solenoid driving direction and the control pressure Pc flowing from the Pc port at the time of driving the solenoid is applied as a drag force of the CS valve element, there is a possibility that the responsiveness of the CS valve element decreases. 
     The present invention is achieved focusing on such a problem, and an object thereof is to provide a capacity control valve capable of immediately operating a CS valve element. 
     Solution to Problem 
     In order to solve the foregoing problem, a capacity control valve according to the present invention is a capacity control valve includes: a valve housing that is provided with a suction port through which a suction fluid of a suction pressure passes and a control port through which a control fluid of a control pressure passes; a CS valve that includes a CS valve element which is axially driven by a solenoid and a CS valve seat which is provided between the suction port and the control port and is brought into contact with and separated from the CS valve element; and biasing member configured to bias the CS valve element in a valve closing direction of the CS valve, wherein a space is formed inside the valve housing in opposition to the solenoid through the CS valve element and the suction fluid flows into the space. According to the aforesaid feature of the present invention, since the suction fluid having a pressure lower than that of the control fluid flows into the space on the side opposite to the solenoid which is on the solenoid driving direction side in relation to the CS valve element, a drag force applied to the CS valve element at the time of driving the solenoid can be decreased and the CS valve element can be immediately operated. 
     It may be preferable that the biasing member is disposed in the space. According to this preferable configuration, since the biasing member can be disposed by using the space into which the suction fluid flows, the capacity control valve can be configured with a compact size. 
     It may be preferable that a communication passage for communication between the space and the suction port is provided. According to this preferable configuration, the control fluid can be caused to flow from the suction port formed in the valve housing into the space through the communication passage. 
     It may be preferable that the communication passage is formed in the CS valve element. According to this preferable configuration, since the communication passage is formed in the CS valve element, the processing is simple compared to a case in which the communication passage is formed in the valve housing. 
     It may be preferable that the space and the control port are partitioned. According to this preferable configuration, the suction fluid can be easily maintained in the space. 
     It may be preferable that the space and the control port are partitioned by a bellows. According to this preferable configuration, the space and the control port can be partitioned by a simple configuration. 
     It may be preferable that the space and the control port are partitioned by the CS valve element and the valve housing is provided with a guide hole having an inner periphery which slides on an outer periphery of the CS valve element to guide the CS valve element. According to this preferable configuration, the space and the control port can be partitioned in a sealed state by the CS valve element even when a member for partitioning the space and the control port is not separately provided. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a sectional view showing a structure of a capacity control valve according to a first embodiment of the present invention. 
         FIG. 2  is a sectional view showing a closed state of a CS valve in a non-energized state of the capacity control valve according to the first embodiment of the present invention. 
         FIG. 3  is a sectional view showing an open state of the CS valve in an energized state of the capacity control valve according to the first embodiment of the present invention. 
         FIG. 4  is a sectional view showing a structure of a capacity control valve according to a second embodiment of the present invention. 
         FIG. 5  is a sectional view showing a closed state of a CS valve in a non-energized state of the capacity control valve according to the second embodiment of the present invention. 
         FIG. 6  is a sectional view showing an open state of the CS valve in an energized state of the capacity control valve according to the second embodiment of the present invention. 
         FIG. 7  is a sectional view showing a structure of a capacity control valve according to a third embodiment of the present invention. 
         FIG. 8  is a sectional view showing a closed state of a CS valve in a non-energized state of the capacity control valve according to the third embodiment of the present invention. 
         FIG. 9  is a sectional view showing an open state of the CS valve in an energized state of the capacity control valve according to the third embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Modes for carrying out a capacity control valve according to the present invention will be described below based on embodiments. 
     First Embodiment 
     A capacity control valve according to a first embodiment of the present invention will be described with reference to  FIGS. 1 to 3 . Hereinafter, description will be given with the left and right sides seen from the front side of  FIG. 1  being the left and right sides of the capacity control valve. 
     A capacity control valve V according to the first embodiment of the present invention is assembled into a variable displacement compressor (not shown) used for an air conditioning system of an automobile, etc. By variably controlling pressure of a working fluid (hereinafter, simply referred to as the “fluid”) serving as a coolant, a discharge amount of the variable displacement compressor is controlled and the air conditioning system is adjusted to have a desired cooling ability. 
     First, the variable displacement compressor will be described. The variable displacement compressor has a casing including a discharge chamber, a suction chamber, a control chamber, and plural cylinders. A communication passage providing direct communication between the discharge chamber and the control chamber is provided in the variable displacement compressor and a fixed orifice  9  for adjusting and balancing pressure between the discharge chamber and the control chamber is provided in this communication passage (see  FIGS. 1 to 3 ). 
     The variable displacement compressor also includes a rotating shaft to be driven and rotated by an engine (not shown) installed outside the casing, a swash plate coupled to the rotating shaft in an eccentric state by a hinge mechanism in the control chamber, and plural pistons coupled to the swash plate and fitted reciprocatably in the respective cylinders. With using the capacity control valve V to be driven to open and close by electromagnetic force, a tilt angle of the swash plate is continuously changed by appropriately controlling pressure in the control chamber while utilizing suction pressure Ps of the suction chamber that suctions the fluid, discharge pressure Pd of the discharge chamber that discharges the fluid pressurized by the pistons, and control pressure Pc of the control chamber that houses the swash plate. Thereby, a stroke amount of the pistons is changed to control a discharge amount of the fluid. 
     As shown in  FIG. 1 , the capacity control valve V assembled into the variable displacement compressor adjusts an electric current energized in a coil  86  forming a solenoid  80  and performs open/close control of a CS valve  50  in the capacity control valve V so that the fluid flowing out to the suction chamber from the control chamber is controlled and the control pressure Pc in the control chamber is variably controlled. A discharge fluid of the discharge pressure Pd of the discharge chamber is always supplied to the control chamber via the fixed orifice  9 , and the control pressure Pc in the control chamber can be increased by closing the CS valve  50  in the capacity control valve V. 
     In the present embodiment, the CS valve  50  includes a CS valve element  51  which is a valve element and a CS valve seat  10   a  which is formed on an inner peripheral surface of the valve housing  10  and an axially right end  51   a  of the CS valve element  51  moves to be in contact with and separated from the CS valve seat  10   a  so that the CS valve  50  is opened and closed. 
     Next, a structure of the capacity control valve V will be described. As shown in  FIG. 1 , the capacity control valve V mainly includes a valve housing  10  which is formed of a metal material or a resin material, a CS valve element  51  of which an axially left end portion is disposed inside the valve housing  10 , and a solenoid  80  which is connected to the valve housing  10  and applies drive force to the CS valve element  51 . 
     As shown in  FIGS. 1 to 3 , the CS valve element  51  is a cylindrical body which has a through hole  51   b  formed at the center portion to penetrate in the axial direction and an axially left end portion of a rod  52  disposed to penetrate the coil  86  of the solenoid  80  is press-inserted and fixed to the through hole  51   b . Further, in the CS valve element  51 , a communication passage  51   c  which penetrates in the axial direction is formed at a position shifted from the through hole  51   b  in the radial direction. In addition, the communication passage  51   c  may be provided at a plurality of positions and this is preferable in that the suction fluid can easily flow in and out. 
     As shown in  FIGS. 1 and 2 , the valve housing  10  is provided with a Ps port  11  which is a suction port communicating with the suction chamber of the variable displacement compressor and a Pc port  12  which is a control port communicating with the control chamber of the variable displacement compressor. The Ps port  11  is formed on the axially right side in relation to the Pc port  12 , specifically, the CS valve seat  10   a.    
     A suction fluid supply chamber  13  to which the suction fluid is supplied from the Ps port  11 , a control fluid supply chamber  14  to which the control fluid is supplied from the Pc port  12 , a valve opening portion  15  which is disposed between the suction fluid supply chamber  13  and the control fluid supply chamber  14  and in which the CS valve seat  10   a  is formed at the axially left edge portion, a recessed portion  10   d  which opens to the axially left side and is disposed on the axially left side in relation to the control fluid supply chamber  14 , and a guide hole  10   b  which is provided in the bottom of the recessed portion  10   d , that is, the axially right end of the recessed portion  10   d  and is slidable on the outer peripheral surface of the CS valve element  51  in a substantially sealed state are provided inside the valve housing  10 . 
     An opening portion of the axially left end of the recessed portion  10   d  is closed by the lid member  16  and a space S defined by the recessed portion  10   d , the lid member  16 , and the CS valve element  51  is formed inside the valve housing  10 . In addition, the inner peripheral surface of the guide hole  10   b  and the outer peripheral surface of the CS valve element  51  are slightly separated from each other in the radial direction so that a minute gap is formed therebetween, the CS valve element  51  is smoothly relatively movable in the axial direction with respect to the valve housing  10 , and the gap functions as a clearance seal that substantially seals the space S and the control fluid supply chamber  14 . 
     The suction fluid supply chamber  13  and the space S communicate with each other by the communication passage  51   c  formed in the CS valve element  51 . That is, the suction fluid supplied into the suction fluid supply chamber  13  flows into the space S through the communication passage  51   c . Further, a spring  17  which is bias means biasing the CS valve element  51  rightward in the axial direction is disposed in the space S. 
     In the valve housing  10 , a recessed portion  10   c  of which an inner radial side of an axially right end is recessed leftward in the axial direction is formed and a flange portion  82   d  of the center post  82  is inserted and fitted from the axially right side so as to be integrally connected and fixed in a substantially sealed state. In addition, an opening end on the side of the solenoid  80  of the suction fluid supply chamber  13  is formed on the inner radial side of the bottom surface of the recessed portion  10   c  of the valve housing  10 . 
     As shown in  FIG. 1 , the solenoid  80  mainly includes a casing  81  which has an opening portion  81   a  opening to the axially left side, a substantially cylindrical center post  82  which is inserted into the opening portion  81   a  of the casing  81  from the axially left side and is fixed to the inner radial side of the casing  81 , the rod  52  which is inserted through the center post  82 , is axially and reciprocatably movable, and is disposed so that an axially left end portion is located on the axially left side in relation to the CS valve seat  10   a , the CS valve element  51  which is press-inserted and fixed to the axially left end portion of the rod  52 , a movable iron core  84  into which the axially right end portion of the rod  52  is inserted and fixed, and the excitation coil  86  which is wound on the outside of the center post  82  through a bobbin. 
     The casing  81  is provided with a recessed portion  81   b  which is formed by recessing the inner radial side of the axially left end rightward in the axial direction and the axially right end portion of the valve housing  10  is inserted and fixed to the recessed portion  81   b  in a substantially sealed state. 
     The center post  82  is formed from a rigid body that is a magnetic material such as iron or silicon steel and includes a cylindrical portion  82   b  that extends in the axial direction and is provided with an insertion hole  82   c  into which the rod  52  is inserted and an annular flange portion  82   d  that extends radially outward from the outer peripheral surface of the axially left end portion of the cylindrical portion  82   b.    
     Further, the center post  82  is inserted and fixed to the recessed portion  10   c  of the valve housing  10  inserted and fixed to the recessed portion  81   b  of the casing  81  in a substantially sealed state while the axially right end surface of the flange portion  82   d  comes into contact with the bottom surface of the recessed portion  81   b  of the casing  81  from the axially left side. That is, the center post  82  is fixed by sandwiching the flange portion  82   d  between the bottom surface of the recessed portion  81   b  of the casing  81  and the bottom surface of the recessed portion  10   c  of the valve housing  10  from both sides in the axial direction. 
     Next, actions of the capacity control valve V, mainly actions of opening and closing the CS valve  50  will be described. 
     First, a non-energized state of the capacity control valve V will be described. As shown in  FIGS. 1 and 2 , in a non-energized state of the capacity control valve V, the CS valve element  51  is pressed to the axially right side by the bias force of the spring  17  so that the axially right end  51   a  of the CS valve element  51  is seated on the CS valve seat  10   a  to close the CS valve  50 . Specifically, the edge portion of the axially right end  51   a  of the CS valve element  51  is seated on the CS valve seat  10   a  formed in a tapered shape to be enlarged toward the axially left side. 
     At this time, to the CS valve element  51 , the bias force F sp  of the spring  17  and force F P1  by pressure of the fluid to an axially left end surface of the CS valve element  51  are applied to the axially right side and force F P2  by pressure of the fluid to the axially right end surface of the CS valve element  51  is applied to the axially left side. That is, given that the right side is the positive side, force F rod =F sp +F P1 −F P2  is applied to the CS valve element  51 . 
     Specifically, a fluid inside the space S is applied to the axially left end surface of the CS valve element  51  and a fluid inside the suction fluid supply chamber  13  is applied to the axially right end surface of the CS valve element  51 . Since the suction fluid supply chamber  13  and the space S communicate with each other by the communication passage  51   c  formed in the CS valve element  51 , the suction fluid supplied from the Ps port  11  flows to the space S and the suction fluid supply chamber  13 . Further, the axially left end surface of the CS valve element  51  is formed to have the same diameter as that of the axially right end surface. In other words, an effective pressure receiving area A of the CS valve element  51  where the fluid of the space S is applied is the same as an effective pressure receiving area B of the CS valve element  51  where the fluid inside the suction fluid supply chamber  13  is applied (i.e., A=B). 
     In this way, since the fluid flowing into the space S and the suction fluid supply chamber  13  is the same as the suction fluid supplied from the Pc port  12  and the effective pressure receiving areas A and B of the CS valve element  51  are the same, the force F P1  by the pressure of the fluid to the axially left end surface of the CS valve element  51  and the force F P2  to the axially right end surface of the CS valve element  51  are the same (i.e., F P1 =F P2 ) and the force F P1  by the pressure of the fluid and the force F P2  by the pressure of the fluid are canceled. That is, given that the right side is the positive side, the force F rod =F sp  is substantially applied to the CS valve element  51 . 
     Next, an energized state of the capacity control valve V will be described. As shown in  FIGS. 1 and 3 , in the capacity control valve V, in an energized state, that is, at the time of normal control or so-called duty control, when electromagnetic force F sol  generated by applying an electric current to the solenoid  80  exceeds the force F rod  (i.e., F sol &gt;F rod ), the movable iron core  84  is pulled toward the axially left side, that is, toward the center post  82  and both the CS valve element  51  and the rod  52  fixed to the movable iron core  84  are moved toward the axially left side so that the axially right end  51   a  of the CS valve element  51  is separated from the CS valve seat  10   a  of the valve housing  10  to open the CS valve  50 . Further, the movable iron core  84  contacts the axially right side of the center post  82  at the time of driving the solenoid  80 , the further separation of the CS valve element  51  from the CS valve seat  10   a  is regulated. In addition, the axially left end of the rod  52  may contact the shaft portion protruding rightward from the lid member  16  to regulate the movement of the CS valve element  51 . 
     At this time, to the CS valve element  51 , the electromagnetic force F sol  is applied on the axially left side, and the force F rod  is applied on the axially right side. That is, given that the right side is the positive side, force F rod −F sol  is applied to the CS valve element  51 . 
     In this way, the capacity control valve V performs Pc-Ps control by opening and closing the CS valve  50  so that the control fluid of the control pressure Pc supplied from the Pc port  12  is supplied to the suction chamber through the Ps port  11  to decrease the control pressure Pc of the control chamber. In other words, the discharge fluid of the discharge pressure Pd having a high pressure is not directly controlled. Therefore, it is possible to finely change the control pressure Pc in accordance with the valve opening degree of the CS valve  50  adjusted by the balance of the electromagnetic force of the solenoid  80  and the bias force of the spring  17 . 
     As described above, since the space S is formed on the driving direction side of the solenoid  80  in relation to the CS valve element  51 , that is, the operation direction side of the CS valve element  51  and the suction fluid having a pressure lower than that of the control fluid flows into this space S, it is possible to decrease a drag force applied to the CS valve element  51  when the CS valve  50  is switched from the closed state to the open state and to immediately operate the CS valve element  51 . In particular, since the capacity control valve V is formed in a normally closed type in which the CS valve element  51  is biased by the spring  17  in the valve closing direction of the CS valve  50 , it is possible to promptly decrease the control pressure Pc by immediately operating the CS valve element  51  to open the CS valve  50 . 
     Further, since the spring  17  is disposed in the space S into which the suction fluid flows, it is not necessary to ensure a space for disposing the spring  17  on the side of the solenoid  80  and it is possible to configure the capacity control valve V in a compact size. Further, since the spring  17  is disposed on the side opposite to the solenoid  80  in the CS valve element  51 , it is possible to stably operate the CS valve element  51 . 
     Further, the communication passage  51   c  is formed for communication between the space S and the Ps port  11  and the control fluid can flow from the Ps port  11  formed in the valve housing  10  to the space S through the communication passage  51   c . Accordingly, it is not necessary to form, for example, a suction port in the valve housing  10  or the lid member  16  separately from the Ps port  11  and it is possible to simplify the structure of the capacity control valve V. 
     Further, since the communication passage  51   c  is formed to penetrate the CS valve element  51  in the axial direction, it is easy to process the communication passage for communication between the space S and the Ps port  11  compared to a case in which the communication passage is formed in the valve housing  10 . 
     Further, since the space S and the Pc port  12  are partitioned by the CS valve element  51 , the valve housing  10  is provided with the guide hole  10   b  which guides the movement of the CS valve element  51 , and the space S and the Pc port  12  are partitioned in a substantially sealed state by the clearance seal formed between the inner peripheral surface of the guide hole  10   b  and the outer peripheral surface of the CS valve element  51 , it is possible to suppress the control fluid from flowing into the space S in the closed state of the CS valve  50 . In other words, since it is easy to hold the suction fluid inside the space S, it is possible to reliably decrease a drag force applied to the CS valve element  51  when the CS valve  50  is switched from the closed state to the open state. Further, since the space S and the Pc port  12  are partitioned in a substantially sealed state by the clearance seal formed between the inner peripheral surface of the guide hole  10   b  and the outer peripheral surface of the CS valve element  51 , it is not necessary to separately provide a member for partitioning the space S and the Pc port  12  and it is possible to decrease the number of parts and to simplify the structure of the capacity control valve V. 
     Further, since the valve housing  10  is provided with the guide hole  10   b  through which the CS valve element  51  is inserted, it is possible to increase the accuracy of the operation of the CS valve element  51  by guiding the CS valve element  51  to the guide hole  10   b . Further, since the CS valve seat  10   a  and the guide hole  10   b  are integrally formed with each other in the valve housing  10 , it is possible to provide a compact capacity control valve V with a small number of parts. 
     Additionally, in the first embodiment, a case has been described in which the effective pressure receiving area A of the CS valve element  51  where the fluid of the space S is applied is the same as the effective pressure receiving area B of the CS valve element  51  where the fluid inside the suction fluid supply chamber  13  is applied. However, the effective pressure receiving area A may be slightly larger than the effective pressure receiving area B (i.e., A&gt;B) so that the CS valve  50  is reliably maintained in the closed state and the effective pressure receiving area A may be slightly smaller than the effective pressure receiving area B (i.e., A&lt;B) so that the CS valve  50  is easily maintained in the open state. 
     Second Embodiment 
     A capacity control valve according to a second embodiment of the present invention will be described with reference to  FIGS. 4 to 6 . Duplicated description for the same configurations as the first embodiment is omitted. 
     As shown in  FIGS. 4 and 5 , in the second embodiment, the CS valve element  151  of the CS valve  150  is formed in a tapered shape so that an axially right end  151   a  is tapered to the axially right side and is seated on the CS valve seat  10   a  in a wide surface in the closed state of the CS valve  150 . Further, a communication passage  151   c  is formed in the CS valve element  151  to penetrate in the axial direction. Further, the axially right end surface of the CS valve element  151  is slightly smaller than the axially left end surface of the CS valve element  151 . 
     The control fluid supply chamber  14  of the second embodiment communicates with the recessed portion  10   d  and a bellows  18  which is bias means for biasing the CS valve element  151  to the axially right side, that is, in the valve closing direction of the CS valve  150  is disposed in the control fluid supply chamber  14  instead of the spring  17 . In the bellows  18 , the axially left end is fixed to a lid member  161  closing the recessed portion  10   d  in a substantially sealed state and the axially right end is fixed to the axially left end surface of the CS valve element  151  in a substantially sealed state so that a space S 1  is formed therein. Further, the suction fluid supply chamber  13  communicates with the space S 1  through the communication passage  151   c  and the suction fluid inside the suction fluid supply chamber  13  flows into the space S 1 . That is, the bellows  18  partitions the space S 1  and the control fluid supply chamber  14  in a sealed state when the CS valve  150  is in the closed state. In addition, a spring for axial biasing may be assembled to the bellows  18 . That is, an effective pressure receiving area A′ of the bellows  18  is formed to be slightly larger than an effective pressure receiving area B′ on the axially right side of the CS valve element  151  (i.e., A′&gt;B′). 
     Next, actions of the capacity control valve V 1 , mainly actions of opening and closing the CS valve  150  will be described. 
     First, a non-energized state of the capacity control valve V 1  will be described. As shown in  FIGS. 4 and 5 , in a non-energized state of the capacity control valve V, the CS valve element  151  is pressed to the axially right side by the bias force of the bellows  18  so that the axially right end  151   a  of the CS valve element  151  is seated on the CS valve seat  10   a  to close the CS valve  150 . 
     At this time, to the CS valve element  151 , the bias force F bel  of the bellows  18  and force F P1  by pressure of the fluid to the axially left end surface of the CS valve element  151  are applied to the axially right side and force F P2  by pressure of the fluid to the axially right surface of the CS valve element  151  is applied to the axially left side. That is, given that the right side is the positive side, force F rod =F sp +F P1 −F P2  is applied to the CS valve element  151 . 
     Specifically, since the effective pressure receiving area A′ on the axially left side of the CS valve element  151  is slightly larger than the effective pressure receiving area B′ on the axially right side, the force F P1  by the pressure of the fluid to the axially left end surface of the CS valve element  151  is slightly larger than the force F P2  by the pressure of the fluid to the axially right surface of the CS valve element  151  (i.e., F P1 &gt;F P2 ). Accordingly, it is easy to maintain the closed state of the CS valve  150  even when a slight pressure difference is immediately generated between the pressure inside the space S 1  and the pressure inside the suction fluid supply chamber  13 . 
     Next, an energized state of the capacity control valve V 1  will be described. As shown in  FIGS. 4 and 6 , in the capacity control valve V 1 , in an energized state, that is, at the time of normal control or so-called duty control, when electromagnetic force F sol  generated by applying an electric current to the solenoid  80  exceeds the force F rod  (i.e., F sol &gt;F rod ), the movable iron core  84  is pulled toward the axially left side, that is, toward the center post  82  and both the CS valve element  151  and the rod  52  fixed to the movable iron core  84  are moved toward the axially left side so that the axially right end  151   a  of the CS valve element  151  is separated from the CS valve seat  10   a  of the valve housing  10  to open the CS valve  150 . 
     In this way, since the suction fluid flows into the space S 1  formed on the operation direction side of the CS valve element  151 , it is possible to immediately operate the CS valve element  151  by decreasing a drag force applied to the CS valve element  151  when the CS valve  150  is switched from the closed state to the open state. 
     Further, since the space S 1  and the Pc port  12  are partitioned in a substantially sealed state by the bellows  18 , it is possible to prevent the control fluid from flowing into the space S 1  in the closed state of the CS valve  150 . In other words, since it is possible to hold the suction fluid inside the space S 1  in the closed state of the CS valve  150 , it is possible to reliably decrease a drag force applied to the CS valve element  151  when the CS valve  150  is switched from the closed state to the open state. Further, since the bellows  18  partitioning the space S 1  and the Pc port  12  also serves as bias means, the capacity control valve V 1  can have a simple configuration. 
     Additionally, in the second embodiment, a case has been described in which the bellows  18  has a function of partitioning the space S 1  and the Pc port  12  and a function of the bias means, but if the bias means biasing the CS valve element  151  in the valve closing direction is separately provided, the bellows  18  may not have the bias force. 
     Third Embodiment 
     A capacity control valve according to a third embodiment of the present invention will be described with reference to  FIGS. 7 to 9 . Duplicated description for the same configurations as the first embodiment is omitted. 
     As shown in  FIGS. 7 and 8 , a CS valve element  251  includes a large diameter portion  251 A which is movable to be in contact with and separated from the CS valve seat  210   a  of the valve housing  210  and a cylindrical small diameter portion  251 B which protrudes toward the axially right side from the center of the large diameter portion  251 A and an axially left end of a rod  252  is press-inserted and fixed to the small diameter portion  251 B. 
     Further, in the valve housing  210  of the third embodiment, the Ps port  11  is formed on the axially left side in relation to the CS valve seat  210   a  and the Pc port  12  is formed on the axially right side in relation to the CS valve seat  210   a . Further, a space S 2  which is partitioned by a recessed portion  210   d , a lid member  216 , and the CS valve element  251  is formed on the axially left side, that is, the operation direction side of the CS valve element  251  in relation to the CS valve seat  210   a  of the valve housing  210  and the space S 2  functions as the suction fluid supply chamber  13 . Further, in the valve housing  210 , the CS valve seat  210   a  is formed between the control fluid supply chamber  14  and the suction fluid supply chamber  13 . Further, a spring  217  which is bias means for biasing the CS valve element  251  toward the axially right side, that is, toward the CS valve seat  210   a  is disposed in the space S 2 . 
     Next, actions of the capacity control valve V 2 , mainly actions of opening and closing the CS valve  250  will be described. 
     First, a non-energized state of the capacity control valve V 2  will be described. As shown in  FIGS. 7 and 8 , in a non-energized state of the capacity control valve V, the CS valve element  251  is pressed to the axially right side by the bias force of the spring  217  so that an axially right end  251   a  of the large diameter portion  251 A of the CS valve element  251  is seated on the CS valve seat  210   a  to close the CS valve  250 . Specifically, the axially right end  251   a  of the tapered CS valve element  251  is seated on the edge portion of the CS valve seat  210   a.    
     At this time, to the CS valve element  251 , the bias force F sp  of the spring  217  and force F P1  by pressure of the suction fluid to an axially left end surface of the CS valve element  251  are applied to the axially right side and force F P2  by pressure of the control fluid to the axially right surface of the CS valve element  251  is applied to the axially left side. That is, given that the right side is the positive side, force F rod =F sp +F P1 −F P2  is applied to the CS valve element  251 . 
     Next, an energized state of the capacity control valve V will be described. As shown in  FIGS. 7 and 9 , in the capacity control valve V 2 , in an energized state, that is, at the time of normal control or so-called duty control, when electromagnetic force F sol  generated by applying an electric current to the solenoid  80  exceeds the force F rod  (i.e., F sol &gt;F rod ), the movable iron core  84  is pulled toward the axially left side, that is, toward the center post  82  and both the CS valve element  251  and the rod  252  fixed to the movable iron core  84  are moved toward the axially left side so that the axially right end  251   a  of the CS valve element  251  is separated from the CS valve seat  210   a  of the valve housing  210  to open the CS valve  250 . 
     In this way, since the suction fluid flows into the space S 2  formed on the operation direction side of the CS valve element  251 , it is possible to immediately operate the CS valve element  251  by decreasing a drag force applied to the CS valve element  251  when the CS valve  250  is switched from the closed state to the open state. Further, since the control fluid is applied to the axially right surface of the CS valve element  251 , it is easy to immediately operate the CS valve element  251  to the axially left side by a pressure difference between the suction fluid and the control fluid applied to the axially left and right surfaces of the CS valve element  251 . 
     The embodiments of the present invention are described above with the drawings. However, specific configurations are not limited to these embodiments but the present invention includes changes and additions within the range not departing from the scope of the present invention. 
     For example, in the above-described embodiments, a case has been described in which the CS valve element is formed as a member separated from the rod disposed to penetrate the coil  86  of the solenoid  80 , but the present invention is not limited to this. The CS valve element and the rod may be integrally formed with each other. 
     The first embodiment describes that the CS valve seat and the guide hole are integrally formed on the inner peripheral surface of the valve housing. However, the present invention is not limited to this but a valve housing having a CS valve seat and a valve housing having a guide hole may be separately provided. 
     A guide portion is not limited to be formed in the valve housing but may be formed in part of the insertion hole  82   c  of the center post  82 , for example. 
     In the above-described embodiments, a case has been described in which the bias means is disposed inside the space, but the bias means may be disposed in a place other than the space such as the solenoid side. 
     In the first and second embodiments, a case has been described in which the Ps port communicates through the communication passage formed in the CS valve element, but the present invention is not limited to this. The communication passage may be formed in the valve housing. Further, the configuration of the communication passage may be omitted and another Ps port may be formed in the lid member or the valve housing forming the space to communicate with the suction chamber of the variable displacement compressor. 
     REFERENCE SIGNS LIST 
     
         
         
           
               9  Fixed orifice 
               10  Valve housing 
               10   a  CS valve seat 
               10   b  Guide hole 
               11  Ps port 
               12  Pc port 
               13  Suction fluid supply chamber 
               14  Control fluid supply chamber 
               17  Spring (biasing member) 
               18  Bellows (biasing member) 
               50  CS valve 
               51  CS valve element 
               51   c  Communication passage 
               80  Solenoid 
               82  Center post 
               84  Movable iron core 
               86  Coil 
               150  CS valve 
               151  CS valve element 
               151   c  Communication passage 
               210  Valve housing 
               210   a  CS valve seat 
               217  Spring (biasing member) 
               250  CS valve 
               251  CS valve element 
             A, A′, B, B′ Effective pressure receiving area 
             Pc Control pressure 
             Pd Discharge pressure 
             Ps Suction pressure 
             S, S 1 , S 2  Space 
             V, V 1 , V 2  Capacity control valve