Patent Publication Number: US-2023160477-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, to a capacity control valve that controls a discharge amount of a variable displacement compressor used for an air conditioning system of an automobile according to 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 fluid. This tilt angle of the swash plate can be continuously changed by appropriately controlling pressure in a control chamber while utilizing a suction pressure Ps of a suction chamber that suctions the fluid, a discharge pressure Pd of a discharge chamber that discharges the fluid pressurized by the pistons, and a control pressure Pc of the control chamber that houses the swash plate, by means of 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 body is moved in an 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 disclosed in Patent Citation 1 includes a valve housing including a control fluid supply chamber to which a control fluid is supplied, and a suction fluid supply chamber to which a suction fluid is supplied; and a valve body that can be driven by a solenoid to come into contact with and separate from a valve seat formed at an opening edge portion of a flow passage that provides communication between the control fluid supply chamber and the suction fluid supply chamber. The flow passage is opened and closed by the valve body to adjust the control pressure Pc of the control fluid supply chamber. 
     CITATION LIST 
     Patent Literature 
     Patent Citation 1: JP 5983539 B2 (PAGE 8, FIG. 3) 
     SUMMARY OF INVENTION 
     Technical Problem 
     In such a capacity control valve, since the valve body repeatedly comes into contact with and separates from the valve seat in the axial direction, the valve seat requires high wear resistance. In the capacity control valve of Patent Citation 1, the valve housing in which the valve seat is formed is made of a hard material, and not only it is difficult to perform boring, etc. for forming the flow passage, the valve seat, etc., but also the amount of use of the hard material is increased, thereby leading to an increase in production cost, which is a problem. 
     The present invention is conceived in view of such a problem, and an object of the present invention is to provide a capacity control valve that can be produced with good workability and at a low cost. 
     Solution to Problem 
     In order to solve the foregoing problem, according to the present invention, there is provided a capacity control valve including: a valve housing in which a flow passage is formed; and a valve body disposed inside the valve housing and driven by a solenoid. A valve seat member having a tubular shape and including a valve seat on which the valve body is scalable is press-fitted into the valve housing, and at least the valve seat of the valve seat member is harder than the valve housing. According to the aforesaid feature of the present invention, the valve seat member including the valve seat requiring wear resistance is configured separately from the valve housing, so that the valve seat is easily processed, and since the valve seat is made of a hard material harder than the material of the valve housing, the valve housing can be made of a low-cost material, so that the capacity control valve can be produced with good workability and at a low cost. 
     It may be preferable that the valve seat member is formed in a tapered shape that is tapered in a direction of press-fitting into the valve housing. According to this preferable configuration, the insertion of the valve seat member into the valve housing is guided by an outer peripheral surface of the valve seat member formed in a tapered shape, so that axis misalignment of the valve seat member with respect to the valve housing is suppressed and the accuracy of positioning of an axis of the valve seat with respect to the valve body is increased. 
      It may be preferable that the valve body has a contact portion that comes into contact with the valve seat and that has a curved surface shape. According to this preferable configuration, even when axis misalignment of the valve seat member with respect to the valve housing is generated, the contact portion of the valve body is reliably seatable on the valve seat. 
     It may be preferable that the contact portion of the valve body is a part of a spherical surface having a constant radius of curvature. According to this preferable configuration, even when axis misalignment of the valve seat member with respect to the valve housing is generated, the contact portion of the valve body is more reliably seatable on the valve seat. 
     It may be preferable that the valve housing is provided a receiving portion that receives an insertion end portion of the valve seat member. According to this preferable configuration, the insertion end portion of the valve seat member is brought into contact with the receiving portion, so that the progress of insertion of the valve seat member into the valve housing can be defined and sealing between the valve housing and the valve seat member can be improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a first embodiment of the present invention. 
         FIG.  2    is a cross-sectional view showing a state where the CS valve is closed in an energized state of the capacity control valve of the first embodiment (e.g., in a normal control state). 
         FIG.  3    is a cross-sectional view showing a state where a valve seat member is press-fitted into a valve housing of the capacity control valve of the first embodiment. 
         FIG.  4    is a front view showing a modification example of the valve seat member. 
         FIG.  5    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a second embodiment of the present invention. 
         FIG.  6    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a third embodiment of the present invention. 
         FIG.  7    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a fourth embodiment of the present invention. 
         FIG.  8    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a fifth embodiment of the present invention. 
         FIG.  9    is a cross-sectional view showing a state where a CS valve is opened in a non-energized state of a capacity control valve according to a sixth 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, a description will be given based on the assumption that the left and right sides when seen from the front side of  FIG.  1    are left and right sides of the capacity control valve. In detail, a description will be given based on the assumption that the left side of the drawing sheet on which a valve housing  10  is disposed is the left side of the capacity control valve and the right side of the drawing sheet on which a solenoid  80  is disposed is the right side of the capacity control valve. 
     The capacity control valve of the present invention is assembled into a variable displacement compressor (not shown) used for an air conditioning system of an automobile, etc., and by variably controlling the pressure of a working fluid (hereinafter, simply referred to as a “fluid”) that is a refrigerant, controls the discharge amount of the variable displacement compressor to adjust the air conditioning system to have a desired cooling capacity. 
     First, the variable displacement compressor will be described. The variable displacement compressor includes a casing including a discharge chamber, a suction chamber, a control chamber, and a plurality of cylinders. Incidentally, the variable displacement compressor is provided with a communication passage that allows direct communication between the discharge chamber and the control chamber, and the communication passage is provided with a fixed orifice  9  that adjusts and balances pressure between the discharge chamber and the control chamber (refer to  FIGS.  1  and  2   ). 
     In addition, the variable displacement compressor 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 so as to be tiltable by a hinge mechanism in the control chamber; and a plurality of pistons that are coupled to the swash plate and are reciprocatably fitted in the respective cylinders, and appropriately controls pressure in the control chamber while utilizing a suction pressure Ps of the suction chamber that suctions the fluid, a discharge pressure Pd of the discharge chamber that discharges the fluid pressurized by the pistons, and a control pressure Pc of the control chamber that houses the swash plate, by means of a capacity control valve V 1  to be driven to open and close by electromagnetic force, to continuously change the tilt angle of the swash plate, and thus to change the stroke amount of the pistons and to control the discharge amount of the fluid. 
     As shown in  FIGS.  1  and  2   , the capacity control valve V 1  of the first embodiment assembled into the variable displacement compressor adjusts an electric current that energizes a coil  86  forming the solenoid  80 , to perform opening and closing control of a CS valve  50  in the capacity control valve V 1 , and thus to control the fluid flowing out to the suction chamber from the control chamber and to variably control the control pressure Pc in the control chamber. Incidentally, 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 CS valve  50  in the capacity control valve V 1  can be closed to increase the control pressure Pc in the control chamber. 
     In the capacity control valve V 1  of the first embodiment, the CS valve  50  includes a CS valve body  51  that is a valve body and a CS valve seat  40   a  that is a valve seat formed in a valve seat member  40  having a tubular shape and being press-fitted and fixed to a recessed portion  10   a  of the valve housing  10 , and a contact portion  51   a  formed at an axially left end of the CS valve body  51  comes into contact with and separates from the CS valve seat  40   a  in an axial direction to open and close the CS valve  50 . 
     Next, a structure of the capacity control valve V 1  will be described. As shown in  FIGS.  1  and  2   , the capacity control valve V 1  mainly includes the valve housing  10  and the valve seat member  40  each being made of a metallic material; the CS valve body  51  disposed inside the valve housing  10  so as to be reciprocatable in the axial direction; and the solenoid  80  connected to the valve housing  10  to exert a driving force on the CS valve body  51 . 
     As shown in  FIGS.  1  and  2   , the CS valve body  51  includes a large-diameter portion  51   b  that is a columnar body made of a metallic material or a resin material and having a constant cross section, and a small-diameter portion  51   c  extending from a radially inner side of an axially right end of the large-diameter portion  51   b  to the right in the axial direction, and also serves as a rod that is disposed to penetrate through the coil  86  of the solenoid  80 . 
     The contact portion  51   a  having a curved surface shape and bulging out toward the CS valve seat  40   a  is formed on an axially left end surface of the CS valve body  51 , namely, on an axially left end surface of the large-diameter portion  51   b . In detail, the curved surface shape of the contact portion  51   a  is formed by a part of a spherical surface having a constant radius of curvature. Incidentally, the curved surface shape of the contact portion  51   a  may not be formed by a part of a spherical surface having a constant radius of curvature as long as the contact portion  51   a  is seatable on the valve seat. 
     As shown in  FIGS.  1  and  2   , the solenoid  80  mainly includes a casing  81  including an opening portion  81   a  that is open to the left in the axial direction; a center post  82  having a substantially cylindrical shape and being inserted into the opening portion  81   a  of the casing  81  from the left in the axial direction to be disposed between a radially inner side of the casing  81  and a radially inner side of the valve housing  10 ; the CS valve body  51  which is inserted into the center post  82  so as to be reciprocatable in the axial direction and of which an axially left end portion is disposed inside the valve housing  10 ; a movable iron core  84  to which the small-diameter portion  51   c  of the CS valve body  51  is inserted and fixed; a coil spring  85  provided between the center post  82  and the movable iron core  84  to bias the movable iron core  84  in an axially right direction that is a valve opening direction of the CS valve  50 ; and the coil  86  for excitation wound on an outer side of the center post  82  with a bobbin interposed therebetween. 
     The center post  82  is made of a rigid body that is a magnetic material such as iron or silicon steel, and includes a cylindrical portion  82   b  which extends in the axial direction and in which an insertion hole  82   c  into which the CS valve body  51  is inserted is formed, and a flange portion  82   d  having an annular shape and extending from an outer peripheral surface of an axially left end portion of the cylindrical portion  82   b  in a radially outward direction. 
     As shown in  FIGS.  1  and  2   , a Ps port  11  that penetrates through the valve housing  10  in the radial direction to communicate with the suction chamber of the variable displacement compressor is formed in the valve housing  10 . In addition, the recessed portion  10   a  into which the valve seat member  40  having a tubular shape is press-fitted from the left in the axial direction is formed on an axially left side of the valve housing  10 . Incidentally, the valve seat member  40  is press-fitted and fixed to the recessed portion  10   a , so that a Pc port communicating with the control chamber of the variable displacement compressor through a through-hole  40   b  that penetrates through the valve seat member  40  in the axial direction is formed in the valve housing  10 . 
     A valve chamber  20  is formed inside the valve housing  10 , and the contact portion  51   a  of the CS valve body  51  is disposed in the valve chamber  20  so as to be reciprocatable in the axial direction. In addition, the Ps port  11  extends from an outer peripheral surface of the valve housing  10  in a radially inward direction to communicate with the valve chamber  20 . 
     As described above, inside the valve housing  10 , the through-hole  40   b  of the valve seat member  40 , the valve chamber  20 , and the Ps port  11  form a flow passage that provides communication between the control chamber and the suction chamber of the variable displacement compressor. 
     In addition, a guide hole  10   c  on which an outer peripheral surface of the large-diameter portion  51   b  of the CS valve body  51  is slidable is formed in an inner peripheral surface of the valve housing  10  on an axially right side of the valve chamber  20  to which the solenoid  80  is attached. Incidentally, an inner peripheral surface of the guide hole  10   c  and the outer peripheral surface of the large-diameter portion  51   b  of the CS valve body  51  are slightly separated from each other in a radial direction to form a very small gap CS valve body  51  therebetween, and the CS valve body  51  is smoothly movable relative to the valve housing  10  in the axial direction. 
     As shown in  FIG.  3   , an inner diameter R1 of the recessed portion  10   a  of the valve housing  10  is set to be larger than an inner diameter R2 of the valve chamber  20  (i.e., R1 &gt; R2) , so that a bottom surface of the recessed portion  10   a  forms a receiving portion  10   b  with which a flat surface  40   c  on an axially right side of the valve seat member  40  can be in contact. 
     In addition, the inner diameter R1 of the recessed portion  10   a  of the valve housing  10  is set to be larger than an outer diameter R3 of a tip of an insertion end portion  40   d  of the valve seat member  40  to be described later (i.e., R1 &gt; R3), and to be smaller than an outer diameter R4 of a pressure contact end portion  40   e  of the valve seat member  40  (R1 &lt; R4) . Incidentally, the outer diameter R4 of the pressure contact end portion  40   e  of the valve seat member  40  may be the same as the inner diameter R1 of the recessed portion  10   a  of the valve housing  10  (i.e., R1 = R4) . 
     Here, the valve seat member  40  will be described. As shown in  FIG.  3   , the valve seat member  40  is made of a metallic material harder than a metallic material used for the valve housing  10 . Further, the valve seat member  40  may be made of a material that is different from that of the CS valve body  51 . 
     In addition, the valve seat member  40  has a tubular shape in which the through-hole  40   b  penetrating therethrough in the axial direction is formed. The flat surface  40   c  having an annular shape, and the CS valve seat  40   a  having a tapered shape that is continuous with the flat surface  40   c  from a radially inner side and that is gradually reduced in diameter toward the left in the axial direction are formed at an axially right end portion of the valve seat member  40  from a radially outer side to the radially inner side. In addition, a tapered surface  40   g  that is continuous from a radially inner side of an end surface  40   f  having an annular shape and that is gradually reduced in diameter toward the right in the axial direction is formed at an axially left end portion of the valve seat member  40  from the radially outer side to the radially inner side. In addition, the CS valve seat  40   a  and the tapered surface  40   g  are formed to be continuous with an inner peripheral surface of the through-hole  40   b . 
     In addition, the insertion end portion  40   d  having a tapered shape of which an outer peripheral surface is gradually reduced in diameter toward a tip side, namely, toward the right in the axial direction is formed at the axially right end portion of the valve seat member  40 . In addition, the pressure contact end portion  40   e  of which an outer peripheral surface extends parallel to the through-hole  40   b  is formed at the axially left end portion of the valve seat member  40 . Namely, the valve seat member  40  is formed in a tapered shape that is tapered in a direction of press-fitting into the recessed portion  10   a  of the valve housing  10 . Incidentally, a rounded portion  40   h  having a curved surface shape is formed in an annular shape between the end surface  40   f  on an axially left side of the valve seat member  40  and an outer peripheral surface of the pressure contact end portion  40   e . 
     Accordingly, when the valve seat member  40  is press-fitted and fixed to the recessed portion  10   a  of the valve housing  10 , the insertion of the valve seat member  40  into the recessed portion  10   a  is guided by the outer peripheral surface of the insertion end portion  40   d  having a tapered shape, and axis misalignment of the valve seat member  40  with respect to the valve housing  10  is suppressed, namely, the valve seat member  40  is aligned. 
     In addition, when the insertion end portion  40   d  is inserted into the recessed portion  10   a , since the diameter of the outer peripheral surface on an axially left side of the insertion end portion  40   d  is larger than the inner diameter R1 of the recessed portion  10   a , the outer peripheral surface of the insertion end portion  40   d  easily receives contact pressure from an inner peripheral surface of the recessed portion  10   a  over an entire circumference, so that the valve seat member  40  can be stably press-fitted and fixed to the valve housing  10 . 
     In addition, the flat surface  40   c  on the axially right side of the insertion end portion  40   d  is brought into contact with the receiving portion  10   b  formed of the bottom surface of the recessed portion  10   a , in the axial direction, so that the progress of insertion of the valve seat member  40  into the recessed portion  10   a  can be defined and sealing between the valve housing  10  and the valve seat member  40  can be improved. 
     As shown in  FIGS.  1  and  2   , a recessed portion  10   d  that is recessed to the left in the axial direction is formed on the axially right side of the valve housing  10 , the flange portion  82   d  of the center post  82  is inserted from the right in the axial direction to be fixed to the valve housing  10  in a substantially sealed state, and the casing  81  is inserted from the right in the axial direction to be fixed to the valve housing  10  in a substantially sealed state, so that the valve housing  10 , the center post  82 , and the casing  81  are integrally connected to each other. 
      As described above, in a state where the valve housing  10 , the center post  82 , and the casing  81  are integrally connected to each other, an axially right end surface of the valve housing  10  and a side surface on an axially right side of the flange portion  82   d  of the center post  82  are in contact with a bottom surface of a recessed portion  81   b  formed on an axially left side of the casing  81 , and a bottom surface of the recessed portion  10   d  of the valve housing  10  and an axially left end surface of the center post  82  are separated from each other in the axial direction to form a gap therebetween. 
     In addition, a through-hole  21  extending between an axially left end surface of the valve housing  10  and a bottom portion of the recessed portion  10   d  in the axial direction is formed in the valve housing  10 . The through-hole  21  includes a small-diameter hole portion  211  of which an axially left end communicates with the control chamber of the variable displacement compressor, and a large-diameter hole portion  212  having a diameter larger than that of the small-diameter hole portion  211  and extending continuously from an axially right end of the small-diameter hole portion  211 . An axially right end of the large-diameter hole portion  212  is open to the gap formed between the bottom surface of the recessed portion  10   d  and the axially left end surface of the center post  82 . Incidentally, the control fluid of the control pressure Pc is supplied from the control chamber of the variable displacement compressor into the small-diameter hole portion  211  of the through-hole  21  and into the through-hole  40   b  of the valve seat member  40 . 
     An actuating valve body  31  having a ball shape, and a return spring  32  of which an axially right end is fixed to the axially left end surface of the center post  82  and of which an axially left end is in contact with the actuating valve body  31  from the right in the axial direction are disposed in the large-diameter hole portion  212  of the through-hole  21 , and the actuating valve body  31  is biased to the left in the axial direction by the return spring  32 . The actuating valve body  31  and the return spring  32  form a pressure-actuated valve  30  that controls communication between the control chamber of the variable displacement compressor and an internal space S of the casing  81  in the through-hole  21 . 
     Although not shown for convenience of description, when the control pressure Pc is high, the actuating valve body  31  of the pressure-actuated valve  30  moves to the right in the axial direction against a biasing force of the return spring  32  and against the pressure of the fluid in the internal space S of the casing  81 , to be separated from a valve seat  213  having a tapered shape and being formed at a connecting portion between the axially right end of the small-diameter hole portion  211  and an axially left end of the large-diameter hole portion  212  in the through-hole  21 , so that the pressure-actuated valve  30  is opened. Accordingly, the control chamber of the variable displacement compressor and the internal space S of the casing  81  communicate with each other via the through-hole  21 , the control fluid of the control pressure Pc is supplied from the control chamber of the variable displacement compressor to the internal space S of the casing  81  through the through-hole  21 , and a pressure difference between the control pressure Pc of the control chamber of the variable displacement compressor and the pressure of the fluid in the internal space S of the casing  81  is decreased. Therefore, the influence of a force induced by the control pressure Pc of the control fluid in the through-hole  40   b  of the valve seat member  40  which acts on the CS valve body  51  is decreased, so that the CS valve body  51  can be smoothly operated to the left in the axial direction, namely, in a valve closing direction, and responsiveness to high output control of the variable displacement compressor can be improved. 
     Incidentally, in the valve housing  10 , since the very small gap between the inner peripheral surface of the guide hole  10   c  and the outer peripheral surface of the large-diameter portion  51   b  of the CS valve body  51  functions as a throttle, the fluid in the internal space S of the casing  81  can be gently released to the Ps port  11 , and the state where the pressure difference between the pressure of the fluid in the valve chamber  20  and the pressure of the fluid in the internal space S of the casing  81  is small is maintained when not used for a long time. 
     As described above, in the capacity control valve V 1  of the present embodiment, the valve seat member  40  having a tubular shape is press-fitted into the valve housing  10 , the valve seat member  40  including the CS valve seat  40   a  on which the CS valve body  51  is seatable and having a hardness higher than that of the valve housing  10 , and the valve seat member  40  including the CS valve seat  40   a  requiring wear resistance is configured separately from the valve housing  10 , so that the degree of freedom in the processing and the shape of the CS valve seat  40   a  is increased, and since the valve seat member  40  is made of a hard material harder than that of the valve housing  10 , the valve housing  10  can be made of a low-cost material, so that the capacity control valve V 1  can be produced with good workability and at a low cost. 
     In addition, since the recessed portion  10   a  having a large diameter is formed at the axially left end portion of the valve housing  10 , a jig used for boring, for example, a cutting tool having high rigidity can be used to improve workability, so that the valve chamber  20  having a diameter smaller than that of the recessed portion  10   a  can be easily formed and the guide hole  10   c  can be formed to have a small diameter. For this reason, the gap between the inner peripheral surface of the guide hole  10   c  and the outer peripheral surface of the large-diameter portion  51   b  of the CS valve body  51  can be formed smaller, the leakage amount of the fluid can be reduced, and foreign matter resistance can be increased. 
     In addition, when the valve seat member  40  is press-fitted and fixed to the recessed portion  10   a  of the valve housing  10 , since the insertion of the valve seat member  40  into the recessed portion  10   a  is guided by the outer peripheral surface of the insertion end portion  40   d  having a tapered shape and axis misalignmentof the valve seat member  40  with respect to the valve housing  10  is suppressed, even in a case where the processing accuracy of the recessed portion  10   a  is bad, if the processing accuracy of the CS valve seat  40   a  of the valve seat member  40  and the accuracy of press-fitting are high, an axis of the valve seat member  40  can be accurately aligned with the CS valve body  51 . Further, since the movement of the valve seat member  40  relative to the valve housing  10  is prevented the press-fitting and fixing of the valve seat member  40  to the recessed portion  10   a , the state where the axis is accurately aligned with the CS valve body  51  is maintained. 
     In addition, when the valve seat member  40  is press-fitted and fixed to the recessed portion  10   a , of the valve housing  10 , the inner peripheral surface of the recessed portion  10   a  of the valve housing  10  is plastically deformed while being expanded, and easily bulges out to the radially inner side along the rounded portion  40   h  having a curved surface shape on the axially left side of the pressure contact end portion  40   e , so that the valve seat member  40  can be prevented from coming off without using a separate member. 
     In addition, since the tapered surface  40   g  that is continuous with the through-hole  40   b  is formed at the axially left end portion of the valve seat member  40 , the fluid is easily introduced into the through-hole  40   b  of the valve seat member  40  from the control chamber. 
     In addition, since the valve seat member  40  and the CS valve body  51  are made of different materials, the CS valve seat  40   a  of the valve seat member  40  and the contact portion  51   a  of the CS valve body  51  do not stick to each other, so that mutual wear can be suppressed. 
     In addition, since the contact portion  51   a  of the CS valve body  51  that comes into contact with the CS valve seat  40   a  is formed by a part of a spherical surface having a constant radius of curvature, even when axis misalignment is generated at the valve seat member  40  that is press-fitted and fixed to the valve housing  10 , the contact portion  51   a  of the CS valve body  51  is reliably seatable on the CS valve seat  40   a , so that the leakage amount of the fluid at the CS valve  50  can be reduced. 
     Incidentally, as a modification example of the valve seat member, as shown in  FIG.  4   , in a valve seat member  140 , recesses and protrusions each having a triangular shape are formed in an outer peripheral surface of a pressure contact end portion  140   e  extending parallel to the through-hole  40   b , so that when the valve seat member  140  is press-fitted and fixed to the recessed portion  10   a  of the valve housing  10 , a plurality of the recesses and protrusions on the outer peripheral surface of the pressure contact end portion  140   e  bite into the inner peripheral surface of the recessed portion  10   a . Therefore, the axis attachment accuracy of the valve seat member  140  can be improved and the rotation of the valve seat member  140  with respect to the valve housing  10  can be prevented. Incidentally, the recesses and protrusions may be not only formed on the outer peripheral surface of the pressure contact end portion, but also formed to the middle of a tapered outer peripheral surface of an insertion end portion that is continuous with the outer peripheral surface of the pressure contact end portion. In addition, the recesses and protrusions may not be formed to the position of an axially left end of the pressure contact end portion. In addition, the recesses and protrusions may be formed in a quadrilateral shape, a curved shape, etc. Incidentally, the undulating shape in the modification example is applicable to a valve seat member of each of the following embodiments. 
     Second Embodiment 
     A capacity control valve according to a second embodiment of the present invention will be described with reference to  FIG.  5   . Incidentally, a description of duplicated configurations that are the same as the configurations of the first embodiment will be omitted. 
     As shown in  FIG.  5   , in a capacity control valve V 2  according to the second embodiment of the present invention, a valve seat member  240  having substantially the same configuration as that of the first embodiment is press-fitted and fixed to a recessed portion  210   a  of a valve housing  210 . Incidentally, the capacity control valve V 2  does not have the configuration of the pressure-actuated valve  30  (refer to  FIGS.  1  and  2   ) of the first embodiment, and as described above, the configuration of using the valve seat member is applicable to valve housings of capacity control valves of various types. 
     Third Embodiment 
     A capacity control valve according to a third embodiment of the present invention will be described with reference to  FIG.  6   . Incidentally, a description of duplicated configurations that are the same as the configurations of the first and second embodiments will be omitted. Incidentally, although a detailed description will be omitted, in the third and subsequent embodiments, it is needless to say that a configuration of each variable displacement compressor is also different from those of the first and second embodiments depending on a configuration of each capacity control valve. 
     As shown in  FIG.  6   , in a capacity control valve V 3  according to the third embodiment of the present invention, a DC valve  350  includes a DC valve body  351  that is a valve body and a DC valve seat  340   a  that is a valve seat formed in a valve seat member  340  that is press-fitted and fixed to a recessed portion  310   a  of a valve housing  310 , and a contact portion  351   a  of the DC valve body  351  comes into contact with and separates from the DC valve seat  340   a  in an axial direction to open and close the DC valve  350 . 
     The capacity control valve V 3  mainly includes the valve housing  310  and the valve seat member  340  each being made of a metallic material; the DC valve body  351  disposed inside the valve housing  310  so as to be reciprocatable in the axial direction; and the solenoid  80  connected to the valve housing  310  to exert a driving force on the DC valve body  351 . 
     A Pd port  311  communicating with the discharge chamber of the variable displacement compressor and a first Pc port  312  communicating with the control chamber of the variable displacement compressor are formed in the valve housing  310 . In addition, in a liquid refrigerant discharge valve seat member  360  having a cup shape and being inserted and fixed to an axially left end portion of the valve housing  310 , a Ps port  313  penetrating through the liquid refrigerant discharge valve seat member  360  in the radial direction and communicating with the suction chamber of the variable displacement compressor, and a second Pc port  314  penetrating through the liquid refrigerant discharge valve seat member  360  in the axial direction and communicating with the control chamber of the variable displacement compressor are formed. 
     In an annular protrusion portion  310   b  having a rectangular shape in a cross-sectional view and protruding from an inner peripheral surface of the valve housing  310  to a radially inner side, a guide hole  310   c  penetrating through the annular protrusion portion  310   b  in the axial direction is formed, and the recessed portion  310   a  is formed which is recessed from a radially inner side of a side surface on an axially right side of the annular protrusion portion  310   b  to the left in the axial direction and into which the valve seat member  340  having a tubular shape is press-fitted from the right in the axial direction. 
     A valve chamber  320  is formed inside the valve housing  310 , and the contact portion  351   a  of the DC valve body  351  is disposed in the valve chamber  320  so as to be reciprocatable in the axial direction, the contact portion  351   a  being formed in a curved surface shape. In addition, the first Pc port  312  extends from an outer peripheral surface of the valve housing  310  in a radially inward direction to communicate with the valve chamber  320 . In addition, the Pd port  311  extends from the outer peripheral surface of the valve housing  310  in the radially inward direction to communicate with the guide hole  310   c . 
     As described above, inside the valve housing  310 , the Pd port  311 , the guide hole  310   c , a through-hole  340   b  of the valve seat member  340  to be described later, the valve chamber  320 , and the first Pc port  312  form a flow passage that provides communication between the discharge chamber and the control chamber of the variable displacement compressor. 
     The valve seat member  340  is made of a metallic material harder than a metallic material used for the valve housing  310 . Further, the valve seat member  340  may be made of a material that is different from that of the DC valve body  351 . 
     In addition, the valve seat member  340  has a tubular shape in which the through-hole  340   b  penetrating therethrough in the axial direction is formed. In addition, the DC valve seat  340   a  is formed of an inner corner on an axially right side of the valve seat member  340 . 
     In addition, an insertion end portion  340   d  having a tapered shape of which an outer peripheral surface is gradually reduced in diameter toward a tip side, namely, toward the left in the axial direction is formed at an axially left end portion of the valve seat member  340 . In addition, a pressure contact end portion  340   e  of which an outer peripheral surface extends parallel to the through-hole  340   b  is formed at an axially right end portion of the valve seat member  340 . 
     Accordingly, in the capacity control valve V 3  of the third embodiment, the valve seat member  340  having a tubular shape is press-fitted into the valve housing  310 , the valve seat member  340  including the DC valve seat  340   a  on which the DC valve body  351  is seatable and having a hardness higher than that of the valve housing  310 , and the valve seat member  340  including the DC valve seat  340   a  requiring wear resistance is configured separately from the valve housing  310 , so that the degree of freedom in the processing and the shape of the DC valve seat  340   a  is increased, and since the valve seat member  340  is made of a hard material harder than that of the valve housing  310 , the valve housing  310  can be made of a low-cost material, so that the capacity control valve V 3  can be produced with good workability and at a low cost. 
     In addition, since the contact portion  351   a  of the DC valve body  351  that comes into contact with the DC valve seat  340   a  is formed in a curved surface shape and being recessed opposite to the DC valve seat  340   a  in the axial direction, even when axis misalignment is generated at the valve seat member  340  that is press-fitted and fixed to the valve housing  310 , the contact portion  351   a  of the DC valve body  351  is reliably seatable on the DC valve seat  340   a , so that the leakage amount of the fluid at the DC valve  350  can be reduced. 
     Incidentally, unlike the first and second embodiments each including the CS valve, in the capacity control valve V 3 , a flow passage between the Pd port  311  and the first Pc port  312  is opened and closed by the DC valve  350 , and as described above, the configuration of using the valve seat member is applicable to valve housings of capacity control valves of various types. 
      In addition, the capacity control valve V 3  is provided with a liquid refrigerant discharge valve  370 . The liquid refrigerant discharge valve  370  includes a pressure sensitive body  361  that is provided in a pressure sensitive chamber  60  formed between a recessed portion  310   d  formed at the axially left end portion of the valve housing  310  and the liquid refrigerant discharge valve seat member  360 , and a liquid refrigerant discharge valve seat  360   a  formed in an inner surface of the liquid refrigerant discharge valve seat member  360 , and an axially left end  361   a  of the pressure sensitive body  361  comes into contact with and separates from the liquid refrigerant discharge valve seat  360   a  in the axial direction to open and close the liquid refrigerant discharge valve  370 . 
     In addition, a coil spring  362  is provided between a bottom surface of the recessed portion  310   d  of the valve housing  310  and an adapter  371  fixed to an axially right end portion of the pressure sensitive body  361 . The coil spring  362  presses the axially left end  361   a  of the pressure sensitive body  361  toward the liquid refrigerant discharge valve seat  360   a  by means of an elastic restoring force regardless of the expansion and contraction of the pressure sensitive body  361 , and during normal control, the liquid refrigerant discharge valve  370  is prevented from being opened. 
      In addition, the liquid refrigerant discharge valve  370  is opened when a force induced by the control pressure Pc supplied from the second Pc port  314  formed in the liquid refrigerant discharge valve seat member  360  is greater than a biasing force of the coil spring  362 . Specifically, when the variable displacement compressor is stopped and then left in a stopped state for a long time, the suction pressure Ps, the discharge pressure Pd, and the control pressure Pc are equalized, and the control pressure Pc and the suction pressure Ps are much higher than the control pressure Pc and the suction pressure Ps at the time of continuous driving, so that the fluid in the control chamber may be partially liquefied. Since the control pressure Pc is much higher when the variable displacement compressor is started up from this state than at the time of continuous driving, and the liquefied fluid makes it difficult for the control chamber to obtain a maximum capacity, at the start-up of the variable displacement compressor, the liquid refrigerant discharge valve  370  is opened by the control pressure Pc, the second Pc port  314  and the Ps port  313  communicate with each other, and the liquefied fluid is discharged from the control chamber to the suction chamber within a short time, so that responsiveness at the start-up of the variable displacement compressor can be improved. 
     Fourth Embodiment 
      A capacity control valve according to a fourth embodiment of the present invention will be described with reference to  FIG.  7   . Incidentally, a description of duplicated configurations that are the same as the configurations of the third embodiment will be omitted. 
     As shown in  FIG.  7   , in a capacity control valve V 4  according to the fourth embodiment of the present invention, a valve seat member  440  having substantially the same configuration as that of the third embodiment is press-fitted and fixed to a recessed portion  410   a  of a valve housing  410 . Incidentally, the capacity control valve V 4  is a capacity control valve larger than the capacity control valve V 3  of the third embodiment, and the configuration of using the valve seat member is applicable to valve housings of capacity control valves of various sizes. 
     Fifth Embodiment 
     A capacity control valve according to a fifth embodiment of the present invention will be described with reference to  FIG.  8   . Incidentally, a description of duplicated configurations that are the same as the configurations of the first embodiment will be omitted. 
     As shown in  FIG.  8   , in a capacity control valve V 5  according to the fifth embodiment of the present invention, a main valve  550  includes a main and auxiliary valve body  551  that is a valve body and a main valve seat  540   a  that is a valve seat formed in a valve seat member  540  that is press-fitted and fixed to a recessed portion  510   a  of a valve housing  510 , and a contact portion  551   a  formed of an outer corner at an axially left end of the main and auxiliary valve body  551  comes into contact with and separates from the main valve seat  540   a  in an axial direction to open and close the main valve  550 . An auxiliary valve  554  includes the main and auxiliary valve body  551  and an auxiliary valve seat  582   a  that is formed in an axially left end surface of a fixed iron core  582 , and a step portion  551   b  on an axially right side of the main and auxiliary valve body  551  comes into contact with and separates from the auxiliary valve seat  582   a  to open and close the auxiliary valve  554 . A pressure sensitive valve  553  includes an adapter  570  of a pressure sensitive body  561  and a pressure sensitive valve seat  552   a  that is formed at an axially left end of a pressure sensitive valve member  552 , and an axially right end  570   a  of the adapter  570  comes into contact with nd separates from the pressure sensitive valve seat  552   a  to open and close the pressure sensitive valve  553 . 
     The capacity control valve V 5  mainly includes the valve housing  510  and the valve seat member  540  each being made of a metallic material; the main and auxiliary valve body  551  and the pressure sensitive valve member  552  that are disposed inside the valve housing  510  so as to be reciprocatable in the axial direction; the pressure sensitive body  561  that applies a biasing force to the main and auxiliary valve body  551  and to the pressure sensitive valve member  552  to the right in the axial direction according to a fluid pressure therearound; and the solenoid  80  connected to the valve housing  510  to exert a driving force on the main and auxiliary valve body  551  and on the pressure sensitive valve member  552 . 
     A Pd port  511  communicating with the discharge chamber of the variable displacement compressor, a Pc port  512  communicating with the control chamber of the variable displacement compressor, and a Ps port  513  communicating with the suction chamber of the variable displacement compressor are formed in the valve housing  510  . 
     A through-hole  510   c  penetrating through the annular protrusion portion  510   b  in the axial direction is formed in an annular protrusion portion  510   b  having a rectangular shape in a cross-sectional view and protruding from an inner peripheral surface of the valve housing  510  to a radially inner side, and the recessed portion  510   a  is formed which is recessed from a radially inner side of a side surface on an axially left side of the annular protrusion portion  510   b  to the right in the axial direction and into which the valve seat member  540  having a tubular shape is press-fitted from the left in the axial direction. A receiving portion  510   d  that is formed at an axially right end portion of the valve seat member  540  and that can be in contact with a step portion  540   c  is formed in a bottom surface of the recessed portion  510   a . 
     A main valve chamber  520  which communicates with the Pd port  511  and in which the contact portion  551   a  of the main and auxiliary valve body  551  is disposed, an auxiliary valve chamber  530  which communicates with the Ps port  513  and in which a back pressure side of the main and auxiliary valve body  551 , namely, the step portion  551   b  on the axially right side of the main and auxiliary valve body  551  is disposed, and a pressure sensitive chamber  560  which communicates with the Pc port  512  and in which the pressure sensitive valve member  552  and the pressure sensitive body  561  are disposed are formed inside the valve housing  510 . 
     As described above, inside the valve housing  510 , the Pd port  511 , the main valve chamber  520 , the through-hole  510   c , a through-hole  540   b  of the valve seat member  540  to be described later, the pressure sensitive chamber  560 , and the Pc port  512  form a flow passage that provides communication between the discharge chamber and the control chamber of the variable displacement compressor. 
      The valve seat member  540  is made of a metallic material harder than a metallic material used for the valve housing  510 . Further, the valve seat member  540  may be made of a material that is different from that of the main and auxiliary valve body  551 . 
     In addition, the valve seat member  540  has a tubular shape in which the through-hole  540   b  penetrating therethrough in the axial direction is formed. The main valve seat  540   a  having a tapered shape is formed of an axially right end surface of the valve seat member  540 . 
     In addition, an insertion end portion  540   d  having a small diameter of which an outer peripheral surface extends parallel to the through-hole  540   b  is formed at the axially right end portion of the valve seat member  540 . In addition, a pressure contact end portion  540   e  having a large diameter of which an outer peripheral surface extends parallel to the through-hole  540   b  is formed at an axially left end portion of the valve seat member  540 . Accordingly, the step portion  540   c  is formed at the axially right end portion of the valve seat member  540  by the outer peripheral surface of and a side surface on an axially right side of the pressure contact end portion  540   e  and by the outer peripheral surface of the insertion end portion  540   d . Namely, the step portion  540   c  is formed on a radially outer side of the insertion end portion  540   d . 
     Accordingly, in the capacity control valve V 5  of the fifth embodiment, the valve seat member  540  having a tubular shape is press-fitted into the valve housing  510 , the valve seat member  540  including the main valve seat  540   a  on which the main and auxiliary valve body  551  is seatable and having a hardness higher than that of the valve housing  510 , and the valve seat member  540  including the main valve seat  540   a  requiring wear resistance is configured separately from the valve housing  510 , so that the degree of freedom in the processing and the shape of the main valve seat  540   a  is increased, and since the valve seat member  540  is made of a hard material harder than that of the valve housing  510 , the valve housing  510  can be made of a low-cost material, so that the capacity control valve V 5  can be produced with good workability and at a low cost. 
     In addition, since the contact portion  551   a  of the main and auxiliary valve body  551  that comes into contact with the main valve seat  540   a  is formed in a curved surface shape and bulging out toward the main valve seat  540   a , even when axis misalignment is generated at the valve seat member  540  that is press-fitted and fixed to the valve housing  510 , the contact portion  551   a  of the main and auxiliary valve body  551  is reliably seatable on the main valve seat  540   a , so that the leakage amount of the fluid at the main valve  550  can be reduced. 
     In addition, when the valve seat member  540  is press-fitted and fixed to the recessed portion  510   a  of the valve housing  510 , the step portion  540   c  is brought into contact with the receiving portion  510   d  formed of the bottom surface of the recessed portion  510   a , in the axial direction, so that the progress of insertion of the valve seat member  540  into the recessed portion  510   a  can be defined and sealing between the valve housing  510  and the valve seat member  540  can be improved. 
     Incidentally, unlike the first and second embodiments each including the CS valve, in the capacity control valve V 5 , a flow passage between the Pd port  511  and the Pc port  512  is opened and closed by the main valve  550 , and as described above, the configuration of using the valve seat member is applicable to valve housings of capacity control valves of various types. In addition, the capacity control valve V 5  is different from the capacity control valves V 3  and V 4  of the third and fourth embodiments in the shape of the valve housing, the disposition of the ports, etc., and as described above, the configuration of using the valve seat member is applicable to valve housings of various shapes. 
     Sixth Embodiment 
     A capacity control valve according to a sixth embodiment of the present invention will be described with reference to  FIG.  9   . Incidentally, a description of duplicated configurations that are the same as the configurations of the first embodiment will be omitted. 
     As shown in  FIG.  9   , in a capacity control valve V 6  according to the sixth embodiment of the present invention, a valve seat member  640  having substantially the same configuration as that of the fifth embodiment is press-fitted and fixed to a recessed portion  610   a  of a valve housing  610 . Incidentally, the capacity control valve V 6  is a capacity control valve larger than the capacity control valve V 5  of the fifth embodiment, and the configuration of using the valve seat member is applicable to valve housings of capacity control valves of various sizes. 
     The embodiments of the present invention have been described above with reference to the drawings; however, the specific configurations are not limited to the embodiments, and changes or additions that are made without departing from the scope of the present invention are also included in the present invention. 
      For example, in the embodiments, the valve housing and the valve seat member have been described as being made of a metallic material; however, the present invention is not limited thereto, and the valve seat member may be made of a resin material, etc. as long as the valve seat member has a hardness higher than that of a flow passage inner side of the valve housing. In addition, also in this case, it is preferable that the valve seat member is made of a material which is different from that of the valve body. 
     In addition, the valve seat member may be harder than the flow passage inner side of the valve housing, and portions other than the flow passage inner side of the valve housing may be harder than the valve seat member. 
     In addition, at least the valve seat of the valve seat member may be harder than the valve housing, and the valve seat member may not be formed of one member. 
     In addition, the contact portion of the valve body that comes into contact with the valve seat may not be formed in a curved surface shape. 
     In addition, a receiving portion that receives the insertion end portion of the valve seat member may not be formed in the valve housing. 
     In addition, a rounded portion may also be formed in the valve seat members of the third to sixth embodiments as in the valve seat members of the first and second embodiments, so that each of the valve seat members can be prevented from coming off by press-fitting and fixing without using a separate member. 
     In addition, in the embodiments, the valve seat member has been described as being press-fitted and fixed by using a difference in radial dimension between the valve seat member and the housing; however, the present invention is not limited thereto, and the valve seat member may be fixed to the valve housing by inserting the valve seat member into the valve housing and by caulking the valve housing (for example, in  FIG.  1   , a force may be applied to the valve seat member in the radial direction to fix the valve seat member, by caulking a left end surface of the valve housing in the axial direction and by deforming the valve housing in the radial direction). 
     
       
         
           
               
               
             
               
                 REFERENCE SIGNS LIST 
               
             
            
               
                 
                   9 
                 
                 Fixed orifice 
               
               
                 
                   10 
                   a 
                 
                 Recessed portion 
               
               
                 
                   10 
                   b 
                 
                 Receiving portion 
               
               
                 
                   10 
                   c 
                 
                 Guide hole 
               
               
                 
                   10 
                   d 
                 
                 Recessed portion 
               
               
                 
                   11 
                 
                 Ps port 
               
               
                 
                   20 
                 
                 Valve chamber 
               
               
                 
                   21 
                 
                 Through-hole 
               
               
                 
                   30 
                 
                 Pressure-actuated valve 
               
               
                 
                   40 
                 
                 Valve seat member 
               
               
                 
                   40 
                   a 
                 
                 CS valve seat (valve seat) 
               
               
                 
                   40 
                   b 
                 
                 Through-hole 
               
               
                 
                   40 
                   c 
                 
                 Flat surface 
               
               
                 
                   40 
                   d 
                 
                 Insertion end portion 
               
               
                 
                   40 
                   e 
                 
                 Pressure contact end portion 
               
               
                 
                   40 
                   f 
                 
                 End surface 
               
               
                 
                   40 
                   g 
                 
                 Tapered surface 
               
               
                 
                   40 
                   h 
                 
                 Rounded portion 
               
               
                 
                   50 
                 
                 CS valve 
               
               
                 
                   51 
                 
                 CS valve body (valve body) 
               
               
                 
                   51 
                   a 
                 
                 Contact portion 
               
               
                 
                   80 
                 
                 Solenoid 
               
               
                 
                   140 
                 
                 Valve seat member 
               
               
                 
                   140 
                   e 
                 
                 Pressure contact end portion 
               
               
                 S 
                 Space 
               
               
                 V 1  to V 6 
 
                 Capacity control valve