Patent Publication Number: US-9850887-B2

Title: Swash plate type variable displacement compressor

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a swash plate type variable displacement compressor. 
     Japanese Patent Application Publication No. H05-172052 discloses a conventional swash plate type variable displacement compressor (hereinafter referred to as compressor). The compressor has a housing including a front housing, a cylinder block and a rear housing. The housing has therein a suction chamber, a discharge chamber, a swash plate chamber and a plurality of cylinder bores, and a drive shaft is rotatably supported in the housing. The swash plate chamber has therein a swash plate that is supported on the drive shaft for rotation therewith. A link mechanism is provided between the drive shaft and the swash plate that permits changing of the inclination angle of the swash plate, that is, an angle of the swash plate relative to an imaginary plane extending perpendicularly to the axis of the drive shaft. A piston is reciprocally slidably received in each cylinder bore. Each piston has a pair of shoes that functions as part of a conversion mechanism converting the rotation of swash plate into reciprocating motion of the piston in the cylinder bore with a length of stroke that is determined by the inclination angle of the swash plate. The compressor further has an actuator that can change the inclination angle of the swash plate by changing the volume of a control pressure chamber formed in the actuator, and a control mechanism that controls the actuator. 
     The drive shaft has mounted thereon a first connecting member, a second connecting member, a thrust bearing and a moving member which are disposed in this order as seen toward the rear of the compressor. The first connecting member and the second connecting member cooperate to form a link mechanism. Although it is not clear from the above-cited Publication, it is thought that the contact between the first connecting member and the swash plate determines the maximum inclination angle of the swash plate. The second connecting member is rotatable with the drive shaft and movable in the axial direction of the drive shaft. The moving member is not rotated with the drive shaft but movable in the axial direction of the drive shaft. A thrust bearing is provided between the second connecting member and the moving member to support the thrust force. 
     The actuator is disposed in the rear housing and has a pressure control chamber. Pressure in the pressure control chamber causes the moving member to move in the axial direction of the drive shaft. The cylinder block has on the rear side thereof an axial hole and the second connecting member, the thrust bearing and the actuator are accommodated in the axial hole. The moving member has in the outer peripheral surface thereof an O-ring which is in slide contact with the axial hole of the cylinder block. 
     When the pressure of refrigerant in the discharge chamber is introduced into the pressure control chamber by the control mechanism and the pressure in the control chamber is increased, the moving member pushes the second connecting member in the direction that increases the inclination angle of the swash plate. As a result, the discharge volume per rotation of the drive shaft, i.e. the displacement of the compressor, is increased. When no discharge pressure is introduced into the pressure control chamber of the actuator, on the other hand, the pressure in the pressure control chamber is gradually reduced and the moving member ceases to push the second connecting member, with the result that the inclination angle is decreased. Accordingly, the displacement of the compressor is reduced. 
     The compressor needs to be so configured that parts of the compressor are assembled with a thrust allowance in the axial direction, taking into account the ease and efficiency in the assembly in actual production of the compressor. 
     The cylinder bore of the above compressor includes first and second cylinder bores that are formed in a single cylinder block on the opposite sides thereof. In some compressors, the cylinder block may include a first cylinder block having therein the first cylinder bore and a second cylinder block having therein the second cylinder bore, and the first cylinder block and the second cylinder block cooperate to form therebetween a swash plate chamber. In the compressor having such first and second cylinder blocks, a first thrust bearing may be provided between the first cylinder block and the drive shaft so as to receive a first thrust force acting on the drive shaft in one direction when the cylinder blocks are fastened together for assembling and a second thrust bearing may be provided between the second cylinder block and the drive shaft so as to support a second thrust force acting on the drive shaft in the opposite direction when the cylinder blocks are fastened together. 
     The aforementioned thrust allowance is a dimensional difference between the total length of parts as measured in the axial direction of the drive shaft before assembling and a depth of the thrust in the compressor after assembly. The total length of the parts as measured in the axial direction before assembly corresponds to the sum of the thicknesses of the first thrust bearing, the thickness of the second thrust bearing and the length of the drive mechanism of the compressor as measured in the axial direction. The drive mechanism refers to a link mechanism and the actuator located between the first thrust bearing and the second thrust bearing. The depth of the thrust in the assembled compressor corresponds to the length between the outer end surface of the first thrust bearing and the outer end surface of the second thrust bearing. 
     If the thrust allowance becomes excessive, the compressor may have problems such as deformation of the first and second cylinder blocks, increased torque for driving the drive shaft and shortened life of the first and second thrust bearings. This may cause deterioration of product yield in mass production of the compressor. If the thrust allowance is controlled strictly, parts for the compressor need to be subject to strict dimension control, thus increasing the production cost of the compressor. Especially, in the compressor according to the present invention having a complex drive shaft mechanism between the first thrust bearing and the second thrust bearing, as compared with, for example, the double-headed piston type swash plate compressor disclosed in the above Publication, strict dimensional control is imposed on the parts of the compressor. 
     Furthermore, parts of the compressor need to be manufactured under strict dimensional control for the maximum inclination angle of the swash plate to be set accurately and uniformly, which increases the production cost of the compressor. 
     The present invention, which has been made in light of the above-mentioned problems, is directed to providing a swash plate type variable displacement compressor that permits reduction of the production cost of the compressor. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present invention, there is provided a swash plate type variable displacement compressor including a housing having therein a suction chamber, a discharge chamber, a swash plate chamber and a plurality of cylinder bores. The swash plate type variable displacement compressor further includes a drive shaft, a swash plate and a link mechanism. The drive shaft is rotatably supported in the housing, and the swash plate is disposed in the swash plate chamber and rotatable with the drive shaft. The link mechanism is provided between the drive shaft and the swash plate and permits changing an inclination angle of the swash plate to an imaginary plane extending perpendicularly to the axis of drive shaft. The swash plate type variable displacement compressor further includes a piston, a conversion mechanism, an actuator and a control mechanism. The piston is reciprocally movably received in the cylinder bore, and the rotation of the swash plate is converted to a reciprocal motion of the piston by the conversion mechanism. The actuator is disposed in the swash plate chamber and changes the inclination angle of the swash plate under the control of the control mechanism. The actuator includes a partitioning member and a moving member, and a pressure control chamber is formed between the partitioning member and the moving member. The actuator is configured in such a way that the moving member is moved when refrigeration in the discharge chamber is introduced into the pressure control chamber. A support member is fitted on the drive shaft, and contact of the support member with the moving member determines a maximum value of the inclination angle. A thrust bearing is provided between the housing and the drive shaft which supports a thrust force exerted by the support member. The support member includes a cylindrical portion. The position of the cylindrical portion is adjustable along the axis of the drive shaft, and the cylindrical portion projects beyond one end of the drive shaft. 
     Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a longitudinal cross-sectional view of a compressor according to a first embodiment of the present invention, showing a state of the compressor at its maximum displacement; 
         FIG. 2  is a longitudinal cross-sectional view of the compressor of  FIG. 1 , showing the state of the compressor at its minimum displacement; 
         FIG. 3  is a schematic diagram of a control mechanism of the compressor of  FIG. 1 ; 
         FIG. 4  is partially enlarged fragmentary view of the compressor of  FIG. 1 , showing the rear end of a drive shaft; 
         FIG. 5  is a partially enlarged fragmentary view of a compressor according to a second embodiment of the present invention, showing the rear end of a drive shaft; 
         FIG. 6  is a partially enlarged fragmentary view of a compressor according to a third embodiment of the present invention, showing the state of the compressor with second race removed; 
         FIG. 7  is a partially enlarged fragmentary view of a compressor according to a fourth embodiment of the present invention, showing an adjustment of axial position of a support member by using a screw. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The following will describe a swash plate type variable displacement compressor according to embodiments of the present invention with reference to the accompanying drawings. The compressor according to the embodiment is a swash plate type variable displacement compressor (hereinafter referred to as compressor). The compressor is mounted on a vehicle and forms a part of refrigeration circuit of a vehicle air conditioner. 
     Referring to  FIG. 1 , the compressor of a first embodiment includes a housing  1 , a drive shaft  3 , a swash plate  5 , a link mechanism  7 , a plurality of pistons  9 , a plurality of pairs of shoes  10 A,  10 B and an actuator  13 . As shown in  FIG. 3 , the compressor further includes a control mechanism  15 . 
     As shown in  FIG. 1 , the housing  1  includes a front housing  11 , a rear housing  21  and first and second cylinder blocks  31 ,  41  that are disposed between the front housing  11  and the rear housing  21 . 
     The front housing  11  has therein a first suction chamber  11 A and a first discharge chamber  11 B. The first suction chamber  11 A has an annular shape and is formed inward of the first discharge chamber  11 B. The first discharge chamber  11 B has an annular shape. The front housing  11  is formed with a boss  11 C projecting forward and having therein a shaft seal device  17 . 
     The front housing  11  has therein a front communication passage  11 D. The front communication passage  11 D is in communication at the front end thereof with the first discharge chamber  11 B and the rear end of the front communication passage  11 D is opened at the rear end of the front housing  11 . 
     The rear housing  21  has therein a second suction chamber  21 A, a second discharge chamber  21 B and a pressure adjusting chamber  21 C. The pressure adjusting chamber  21 C is formed in the center of the rear housing  21 . The second suction chamber  21 A has an annular shape and is formed radially outward of the pressure adjusting chamber  21 C. The second discharge chamber  21 B has an annular shape and is located outward of the second suction chamber  21 A. The first and the second suction chambers  11 A,  21 A correspond to the suction chamber of the present invention. The first and second discharge chambers  11 B,  21 B correspond to the discharge chamber of the present invention. 
     The rear housing  21  has therein a rear communication passage  21 D. The rear communication passage  21 D is in communication at the rear end thereof with the second discharge chamber  21 B and the front end of the rear communication passage  21 D is opened at the front end of the rear housing  21 . 
     The first cylinder block  31  and the second cylinder block  41  cooperate to form therebetween a swash plate chamber  51 . The front housing  11 , the first cylinder block  31 , the second cylinder block  41  and the rear housing  21  are arranged and fixed together in the direction of the axis O of the drive shaft  3 . The front housing  11 , the first cylinder block  31  and the second cylinder block  41  correspond to the housing of the presenting invention. 
     The first cylinder block  31  has therein a first shaft hole  31 A through which part of the drive shaft  3  is inserted, a plurality of first cylinder bores  31 B, a first recess  31 C, a first cylinder block passage  31 D and a plurality of first communication passages  31 E. 
     A first radial bearing  19 A is provided in the first shaft hole  31 A. The first cylinder bores  31 B are formed in the first cylinder block  31  around the first shaft hole  31 A and located adjacent to the front end of the drive shaft  3 . The first recess  31 C is formed coaxially and in communication with the first shaft hole  31 A and forms a part of the swash plate chamber  51 . A first thrust bearing  23  is provided in the first recess  31 C at the front end thereof. The front end surface of the first recess  31 C is formed in a plane surface extending perpendicularly to the axis O of the drive shaft  3 . 
     The first cylinder block passage  31 D is formed in the first cylinder block  31  in communication at the front end thereof with the rear end of the front communication passage  11 D in the front housing  11  and the rear end of the first cylinder block passage  31 D is opened at the rear end of the first cylinder block  31 . Each first communication passage  31 E is formed in the first cylinder block  31  in communication at the rear end thereof with the swash plate chamber  51  and the front end of the first communication passage  31 E is opened at the front end of the first cylinder block  31 . 
     The second cylinder block  41  has therein a second shaft hole  41 A through which part of the drive shaft  3  is inserted, a plurality of second cylinder bores  41 B corresponding to the respective first cylinder bores  31 B, a second recess  41 C, a second cylinder block passage  41 D, a plurality of second communication passages  41 E, a discharge port  41 F that is in communication with the second cylinder block passage  41 D and a suction port  41 G. 
     A second radial bearing  19 B is press-fitted in the second shaft hole  41 A. The second shaft hole  41 A is formed coaxially and in communication with the pressure adjusting chamber  21 C in the rear housing  21 . The second cylinder bores  41 B are formed around second shaft hole  41 A and located adjacent to the rear end of the drive shaft  3 . Each second cylinder bore  41 B is paired with its corresponding first cylinder bore  31 B. The second recess  41 C is formed coaxially and in communication with the second shaft hole  41 A. The second recess  41 C forms a part of the swash plate chamber  51 . A second thrust bearing  25  is provided in the second recess  41 C at the rear end thereof. The rear end surface of the second recess  41 C is formed in a plane surface extending perpendicularly to the axis O of the drive shaft  3 . 
     The second cylinder block passage  41 D is formed in the second cylinder block  41  in communication at the front end thereof with the rear end of the first cylinder block passage  31 D and the rear end of the second cylinder block passage  41 D is in communication with the rear communication passage  21 D at the front end thereof. Each second communication passage  41 E is formed in the second cylinder block  41  in communication at the front end thereof with the swash plate chamber  51  and the rear end of the second communication passage  41 E is opened at the rear end of the second cylinder block  41 . The discharge port  41 F is connected to a condenser (not shown) and the suction port  41 G is connected to an evaporator (not shown), respectively. 
     A first valve unit  33  is disposed between the front housing  11  and the first cylinder block  31 . 
     The first valve unit  33  includes a first valve plate  34 , a first suction valve plate  35 , a first discharge valve plate  36  and a first retainer plate  37 . The first valve plate  34 , the first discharge valve plate  36  and the first retainer plate  37  have therethrough first suction holes  33 A for the respective first cylinder bores  31 B. Each first suction hole  33 A provides a fluid communication between its corresponding first cylinder bore  31 B and the first suction chamber  11 A. 
     The first valve plate  34  and the first suction valve plate  35  have therethrough first discharge holes  33 B for the respective first cylinder bores  31 B. Each first discharge hole  33 B provides a fluid communication between its corresponding first cylinder bore  31 B and the first discharge chamber  11 B. 
     Additionally, the first valve unit  33  has therethrough a plurality of first suction communication holes  33 C. Each first suction communication hole  33 C provides a fluid communication between its corresponding first communication passage  31 E and the first suction chamber  11 A. The first valve plate  34  and the first suction valve plate  35  have therethrough a first discharge communication hole  33 D that provides a fluid communication between the front communication passage  11 D and the first cylinder block passage  31 D. 
     The first suction valve plate  35  is located on the rear side of the first valve plate  34  and has a plurality of first suction reed valves  35 A to open and close the respective first suction holes  33 A. The maximum opening of each first suction reed valve  35 A is determined by a first retainer recess  31 G formed in the first cylinder block  31 . The first discharge valve plate  36  is located on the front side of the first valve plate  34  and has a plurality of first discharge reed valves  36 A to open and close the respective first discharge holes  33 B. The first retainer plate  37  is located on the front side of the first discharge valve plate  36  and determines the maximum opening of each first discharge reed valve  36 A. 
     A second valve unit  43  is formed between the rear housing  21  and the second cylinder block  41 . 
     The second valve unit  43  includes a second valve plate  44 , a second suction valve plate  45 , a second discharge valve plate  46  and a second retainer plate  47 . The second valve plate  44 , the second discharge valve plate  46  and the second retainer plate  47  have therethrough second suction holes  43 A for the respective second cylinder bores  41 B. Each second suction hole  43 A provides a fluid communication between its corresponding second cylinder bore  41 B and the second suction chamber  21 A. 
     The second valve plate  44  and the second suction valve plate  45  have therethrough second discharge holes  43 B for the respective second cylinder bore  41 B. Each second discharge hole  43 B provides a fluid communication between its corresponding second cylinder bore  41 B and the second discharge chamber  21 B. 
     Additionally, the second valve unit  43  has therethrough a plurality of second suction communication holes  43 C. Each second suction communication hole  43 C provides a fluid communication between its corresponding second communication passage  41 E and the second suction chamber  21 A. The second valve plate  44  and the second suction valve plate  45  have therethrough a second discharge communication hole  43 D that provides a fluid communication between the second cylinder block passage  41 D and the rear communication passage  21 D. 
     The second suction valve plate  45  is located on the front side of the second valve plate  44  and has a plurality of second suction reed valves  45 A to open and close the respective second suction hole  43 A. The maximum opening of each second suction reed valve  45 A is determined by a second retainer recess  41 J formed in the second cylinder block  41 . The second discharge valve plate  46  is located on the rear side of the second valve plate  44  and has a plurality of second discharge reed valve  46 A to open and close the respective second discharge hole  43 B by the elastic deformation. The second retainer plate  47  is located on the rear side of the second discharge valve plate  46  and determines the maximum opening of each second discharge reed valve  46 A. 
     The drive shaft  3  is supported in the first and second shaft holes  31 A,  41 A rotatably about its own axis O. The drive shaft  3  includes a drive shaft body  53 , a first small-diameter portion  54  extending rearward from the drive shaft body  53 , a second small-diameter portion  55  extending rearward from the first small-diameter portion  54 . The drive shaft body  53  drives to rotate the swash plate  5  in conjunction with the link mechanism  7 . The drive shaft body  53  has mounted thereon a fixed member  27 , the swash plate  5  and the link mechanism  7 . The first small-diameter portion  54  is integrally formed with the drive shaft body  53 , having a smaller diameter than the drive shaft body  53 , and is received in the second recess  41 C. The second small-diameter portion  55  is integrally formed with the first small-diameter portion  54  and has a smaller diameter than the first small-diameter portion  54 . The first small-diameter portion  54  has at the rear end thereof an annular surface  54 S ( FIG. 4 ), extending from the rear end of the outer peripheral surface of the first small-diameter portion  54  to the front end of the outer peripheral surface of the second small-diameter portion  55 . 
     The fixed member  27  is press-fitted on the front end portion of the drive shaft body  53 . With the drive shaft  3  rotated about the axis O thereof, the fixed member  27  rotates with the drive shaft  3  in sliding contact with the first radial bearing  19 A. The fixed member  27  has a flange  27 A that is in contact with the first thrust bearing  23 . The first thrust bearing  23  receives a first thrust force acting on the drive shaft  3 . A first return spring  29  is fixed at the front end thereof to the fixed member  27 . The first return spring  29  extends in the direction of the axis O from the fixed member  27  toward the swash plate chamber  51 . 
     As shown in  FIG. 4 , a support member  56  that is fitted on the second small-diameter portion  55  of the drive shaft  3  in the second shaft hole  41 A of the second cylinder block  41 . The support member  56  includes a cylindrical portion  56 A and a flange  56 B. The cylindrical portion  56 A is fitted on the second small-diameter portion  55  of the drive shaft  3  and projects out beyond the rear end surface of the second small-diameter portion  55 . In other words, the cylindrical portion  56 A projects beyond one end of the drive shaft  3 . The position of the cylindrical portion  56 A of the support member  56  in the direction of the axis O is adjustable by changing the projection of the cylindrical portion  56 A of the support member  56  beyond the rear end surface of the second small-diameter portion  55  into the pressure adjusting chamber  21 C. 
     The cylindrical portion  56 A of the support member  56  extends in the direction of the axis O and has a radial bearing surface  65 A. The second radial bearing  19 B is mounted on the radial bearing surface  65 A. With the drive shaft  3  rotated about the axis O of the drive shaft  3 , the support member  56  is rotated with the drive shaft  3  in sliding contact with the second radial bearing  19 B. Thus, a radial force acting on the rear end side of the second small-diameter portion  55  of the drive shaft  3  is supported by the radial bearing surface  65 A via the second radial bearing  19 B. In addition, two O-rings  61 ,  62  are provided in the outer peripheral surface of the cylindrical portion  56 A of the support member  56  for sealing between the cylindrical portion  56 A of support member  56  and the second cylinder block  41 . 
     The flange  56 B is formed extending perpendicularly to the axis O from the cylindrical portion  56 A. The flange  56 B has at the front end thereof an annular front end surface  56 C and at the rear end thereof a thrust bearing surface  65 B. The second thrust bearing  25  is fixed to the thrust bearing surface  65 B. The thrust bearing surface  65 B supports a second thrust force acting on the drive shaft  3  between the thrust bearing surface  65 B and the second cylinder block  41 . A predetermined clearance S is formed between the front end surface  56 C of the flange  56 B and the annular surface  54 S of the first small-diameter portion  54  of the drive shaft  3 . 
     The second thrust bearing  25  includes a first race  25 A that is held in contact with the second cylinder block  41 , a second race  25 B that is held in contact with the flange  56 B of the support member  56 , a plurality of rollers  25 C that are provided between the first race  25 A and the second race  25 B and a retainer that retains the rollers  25 C between the first and second races  25 A,  25 B. 
     As shown in  FIG. 1 , the swash plate  5  has a shape of an annular plate shape. The swash plate  5  is fixed to a ring plate  39  that is located at the center of the drive shaft  3 . The ring plate  39  has an annular plate shape and has therethrough at the center thereof a hole  39 A. With the drive shaft  3  inserted through the hole  39 A of the ring plate  39 , the swash plate  5  is disposed and rotatable in the swash plate chamber  51 . 
     The link mechanism  7  is provided in the swash plate chamber  51  so as to permit changing of the inclination angle of the swash plate  5  with respect to an imaginary plane that extends perpendicularly to the axis O of the swash plate  5 . The link mechanism  7  includes a lug arm  49  that has substantially an L-shape. The lug arm  49  is provided between the fixed member  27  and the swash plate  5  in the swash plate chamber  51 . The lug arm  49  is fixed at the front end thereof to the fixed member  27  by the first pin  57 A. M 1  designates a first axis of the first pin  57 A and the rear end of the lug arm  49  is supported so as to be swingable about the axis M 1  relative to the fixed member  27  and hence to the drive shaft  3 . 
     The lug arm  49  is connected at the rear end thereof to one end of the ring plate  39  by the second pin  57 B. The front end of the lug arm  49  is supported so as to be swingable about an axis of the second pin  57 B as a second axis M 2  with respect to the one end of the ring plate  39 , i.e. swash plate  5 . The second axis M 2  extends perpendicularly to the axis O of the drive shaft  3  and parallel to the first axis M 1 . 
     As shown in  FIG. 2 , the lug arm  49  is brought into contact with the flange  27 A of the fixed member  27  when the inclination angle of the swash plate  5  becomes minimum. The lug arm  49 , the first and second pins  57 A,  57 B correspond to the link mechanism of the present invention. 
     As shown in  FIG. 1 , the lug arm  49  has at the rear end thereof a weight  49 A. The weight  49 A extends over approximately half the circumference of the actuator  13 . The weight  49 A may be designed in any suitable shape. 
     The weight  49 A is provided on the rear side of the lug arm  49 , that is, on the side of the lug arm  49  that is opposite from the first axis M 1 . With the lug arm  49  supported by the ring plate  39  at the second pin  57 B, the weight  49 A is located on the rear side of the ring plate  39 , i.e. on the rear side of the swash plate  5 . The centrifugal force caused by the rotation of the swash plate  5  about the axis O of the drive shaft acts on the weight  49 A at the rear surface of the swash plate  5 . 
     Each piston  9  has at the front end thereof a first head portion  9 A and at the rear end thereof a second head portion  9 B, respectively. The first head portion  9 A of the piston  9  is reciprocally movably received in the first cylinder bore  31 B and a first compression chamber  31 F is defined in the first cylinder bore  31 B between the first head portion  9 A and the first valve unit  33 . 
     The second head portion  9 B is integrated with its corresponding first head portion  9 A and reciprocally movably received in the second cylinder bore  41 B. A second compression chamber  41 H is defined in the second cylinder bore  41 B between the second head portion  9 B and the second valve unit  43 . 
     Each piston has therein at the center thereof a piston recess  9 C. A pair of hemispherical shoes  10 A,  10 B is disposed in the piston recess  9 C to hold therebetween the swash plate  5 . The rotation of the swash plate  5  is converted to the reciprocal motion of the piston  9  by way of the shoes  10 A,  10 B. The shoes  10 A,  10 B corresponds to the conversion mechanism of the present invention. The first head portion  9 A and the second head portion  9 B of the piston  9  are reciprocally movable in the first cylinder bore  31 B and the second cylinder bore  41 B, respectively, with a stroke length that is variable according to the inclination angle of the swash plate  5 . 
     The actuator  13  is disposed in the swash plate chamber  51  for changing the inclination angle of the swash plate  5 . The actuator  13  is located rearward of the swash plate  5  and movable into and out of the second recess  41 C. The actuator  13  has a partitioning member  63 , a moving member  64  and a pressure control chamber  65  formed between the partitioning member  63  and the moving member  64 . 
     The partitioning member  63  is fixed on the first small-diameter portion  54  of the drive shaft  3 . The partitioning member  63  has formed therethrough a hole  63 A through which the drive shaft  3  is inserted. An O-ring  67  is provided in the outer periphery of the partitioning member  63  for sealing between the partitioning member  63  and the moving member  64 . A second return spring  69  is disposed between the partitioning member  63  and the ring plate  39 . More specifically, the second return spring  69  is fixed at the rear end thereof to the partitioning member  63  and the front end of the second return spring  69  is fixed to the other end of the ring plate  39 . 
     The moving member  64  is mounted on the first small-diameter portion  54  of the drive shaft  3  and received in the second recess  41 C of the second cylinder block  41  when the swash plate  5  is at its maximum inclination angle position, as shown in  FIG. 1 . The moving member  64  has a bottomed cylindrical shape and an inner diameter that is substantially the same as the outer diameter of the partitioning member  63 . The base portion  64 A forms the rear end of the moving member  64  and extends in radial direction. The base portion  64 A has a hole  64 C through which the first small-diameter portion  54  is inserted. The hole  64 C has an O-ring  68  for sealing between the base portion  64 A of the moving member  64  and the first small-diameter portion  54  of the drive shaft  3 . 
     The peripheral wall portion  64 B is formed extending axially frontward from the outer periphery of base portion  64 A. A connecting portion  74  is formed at the front end of the peripheral wall portion  64 B. The partitioning member  63  is disposed so as to be surrounded by the peripheral wall portion  64 B of the moving member  64 . Thus, the control pressure chamber  65  is formed by and between the partitioning member  63  and the moving member  64 . 
     The moving member  64  is movable by the internal pressure of the pressure control chamber  65  formed between the partitioning member  63  and the moving member  64 . In other words, the actuator  13  is configured in such a way that the moving member  64  is moved when refrigerant in the discharge chamber  21 B is introduced into the pressure control chamber  65 . The pressure control chamber  65  is sealed by the O-rings  67 ,  68 . 
     The moving member  64  is rotatable with the drive shaft  3  and also movable along axis of the drive shaft  3  in sliding contact with the first small-diameter portion  54  of the drive shaft  3 . The partitioning member  63  is rotatable with the drive shaft  3 , but immovable along the drive shaft  3 . The moving member  64  is movable relative to the partitioning member  63  in the direction of the axis O. 
     The connecting portion  74  of the moving member  64  is connected to the other end of the ring plate  39  by the third pin  57 C. Thus, the ring plate  39  and hence swash plate  5  is supported swingably about an axis M 3  of the third pin  57 C as an acting axis. The axis M 3  extends parallel to the axes M 1 , M 2 . The moving member  64  is thus connected to the swash plate  5 . The moving member  64  is brought into contact with the flange  56 B of the support member  56  when the swash plate  5  is tilted to its maximum inclination angle position shown in  FIG. 1 . In other words, the contact of the support member  56  with the moving member  64  determines the maximum value of the inclination angle. 
     The second small-diameter portion  55  and the first small-diameter portion  54  of the drive shaft  3  have therein an in-shaft axial passage  54 A that extends frontward from the rear end of the drive shaft  3  and an in-shaft radial passage  54 B that extends radially from the front end of the axial passage  54 A and is opened at the outer peripheral surface of the first small-diameter portion  54 . The axial passage  54 A is opened at the rear end thereof to the pressure adjusting chamber  21 C. The radial passage  54 B is in communication with the pressure control chamber  65 . Therefore, the pressure control chamber  65  is connected through the radial passage  54 B and the axial passage  54 A to the pressure adjusting chamber  21 C. 
     The drive shaft  3  has at the front end thereof a threaded portion  3 A. The drive shaft  3  is connected to a pulley or a magnetic clutch (neither being shown) through the threaded portion  3 A. 
     As shown in  FIG. 3 , the control mechanism  15  includes a low pressure passage  15 A, a high pressure passage  15 B, a control valve  75 , an orifice  77 , the axial passage  54 A and the radial passage  54 B. 
     The low pressure passage  15 A is connected at one end thereof to the pressure adjusting chamber  21 C and at the other end thereof to the second suction chamber  21 A. Consequently, the pressure control chamber  65 , the pressure adjusting chamber  21 C and the second suction chamber  21 A are connected through the low pressure passage  15 A, the axial passage  54 A and the radial passage  54 B. The high pressure passage  15 B is connected at one end thereof to the pressure adjusting chamber  21 C and at the other end thereof to the second discharge chamber  21 B. As a result, the pressure control chamber  65 , the pressure adjusting chamber  21 C and the second discharge chamber  21 B are connected through the high pressure passage  15 B, the axial passage  54 A and the radial passage  54 B. The high pressure passage  15 B is provided with the orifice  77 . 
     The control valve  75  is connected in the low pressure passage  15 A and controls the opening of the low pressure passage  15 A according to the pressure in the second suction chamber  21 A. 
     The compressor is connected at the suction port  41 G to the evaporator (not shown) and at the discharge port  41 F to the condenser (not shown) by a pipe, respectively. The compressor, the evaporator, an expansion valve and the condenser cooperate to form a refrigeration circuit of a vehicle air conditioner. The evaporator, the expansion valve, the condenser and the pipes are omitted from the illustration in the drawings. 
     In the compressor having the above-described configuration, the rotation of the swash plate  5  driven by the drive shaft  3  causes each piston  9  to reciprocate in its corresponding first and second cylinder bores  31 B,  41 B. Accordingly, the volume of the first and second compression chambers  31 F,  41 F is changed and compression of refrigerant gas is accomplished. In accordance with the reciprocating movement of each piston  9 , suction phase during which refrigerant gas is introduced into the first and second compression chamber  31 F,  41 H, compression phase during in which refrigerant is compressed in the first and second compression chambers  31 F,  41 H and discharge phase during which the compressed refrigerant gas is discharged out from the first and second compression chambers  31 F,  41 H take place repeatedly. 
     In the control mechanism  15  of the compressor, when the opening of the low pressure passage  15 A is increased by the control valve  75 , the pressures in the pressure adjusting chamber  21 C and the control pressure chamber  65  become substantially the same as the pressure in the second suction chamber  21 A. As a result, the moving member  64  of the actuator  13  is moved frontward or toward the lug arm  49 , which causes the swash plate  5  to swing in clockwise direction about the axis M 3 . In addition, the lug arm  49  swings in counterclockwise direction about the second axis M 2  and in counterclockwise direction about the first axis M 1 , which causes the lug arm  49  to move toward the flange  27 A of the fixed member  27 . Consequently, the swash plate  5  swings about the second axis M 2  in the direction that reduces the inclination angle of the swash plate  5 , so that the stroke length of each piston  9  is reduced. Therefore, the discharge volume per rotation of the drive shaft  3  and hence the displacement of the compressor is reduced. 
     When the control valve  75  is closed and decreases the opening of the low pressure passage  15 A, on the other hand, the pressure in the pressure adjusting chamber  21 C is increased and the pressure in the pressure control chamber  65  is increased, accordingly. The moving member  64  of the actuator is moved rearward away from the lug arm  49 . The inclination angle of the swash plate  5  is increased and the stroke length of each piston  9  is increased, accordingly, so that the discharge volume per rotation of the drive shaft  3  and hence the displacement of the compressor is increased. In other words, the control mechanism  15  controls the actuator  13 . 
     In the mass production of the above-described compressor, adjusting the space S between the front end surface  56 C of the flange  56 B of the support member  56  and the annular surface  54 S of the first small-diameter portion  54  of the drive shaft  3  when fastening the first and second cylinder blocks  31 ,  41 , the first and second thrust bearings  23 ,  25  and other parts in the axial direction of the compressor for assembling permits the second thrust bearing  25  provided between the second cylinder block  41  and the first small-diameter portion  54  of the drive shaft  3  to support the thrust force through the support member  56  without performing a strict thrust allowance control. Thus, the compressor is free from deformation of the first and second cylinder blocks  31 ,  41  and the first and second thrust bearings  23 ,  25 , increased torque required for the drive shaft  3  and shortened life of the first and second thrust bearings  23 ,  25  and, therefore, the production yield of the compressor is improved. In addition, the cost of some parts may be reduced because strict dimensional control is not needed for such parts. Axial adjustment of the cylindrical portion  56 A of the support member  56  may be accomplished easily by pushing the projection of the cylindrical portion  56 A beyond the rear end surface of the second small-diameter portion  55 , which facilitates the assembling of the compressor. 
     Furthermore, the structure of the compressor in which the maximum inclination angle of the swash plate  5  is determined by the contact of the flange  56 B of the support member  56  with the moving member  64  helps to minimize the quality variation of compressors without practicing strict dimensional control for parts. 
     Therefore, the present embodiment helps to reduce the manufacturing cost of the compressor. 
     Second Embodiment 
     The following will describe a compressor according to a second embodiment of the present invention with reference to  FIG. 5 . Numeral  141  designates a second cylinder block of the compressor of the second embodiment having therein an annular groove  141 R formed adjacent to the second shaft hole  141 A of the second recess  141 C in the second cylinder block  141 . The annular groove  141 R is formed large enough to extend radially beyond the outer periphery of the rollers  25 C of the second thrust bearing  25  thereby to allow inner peripheral part of the second thrust bearing  25  to be bent rearward. 
     The second thrust bearing  25  is held in contact in the outer peripheral part of the first race  25 A thereof with the bottom of the second recess  141 C. The thrust bearing surface  65 B of the flange  56 B of the support member  65  is held in contact with the inner peripheral part of the second race  25 B. The rest of the configuration of the compressor according to the second embodiment is substantially the same as the first embodiment. 
     In the compressor of the second embodiment, the first race  25 A and the second race  25 B of the thrust bearing  25  are bent when the front housing  11 , the first cylinder block  31 , the second cylinder block  141  and the rear housing  21  are fastened together in the axial direction of the compressor. In other words, the thrust bearing  25  is pressed at the outer peripheral part of the first race  25 A thereof against the second cylinder block  141  and at the inner peripheral part of the second race  25 B thereof against the thrust bearing surface  65 B, respectively, by the fastening force transmitted from the thrust bearing surface  65 B of the support member  56 . Therefore, the first race  25 A and the second race  25 B of the thrust bearing  25  are bent so as to tilt with respect to an imaginary plane extending perpendicularly to the axis O of the drive shaft  3 , so that the thrust fastening allowance is absorbed. The compressor of the second embodiment provides the same effects as the compressor of the first embodiment. 
     Third Embodiment 
     The following will describe a compressor according to a third embodiment of the present invention with reference to  FIG. 6 . The compressor of the third embodiment has a second thrust bearing  125  that includes a first race  125 A, a plurality of rollers  125 C and the retainer (not shown). The first race  125 A is held in contact with the second cylinder block  41 . 
     The compressor of the third embodiment has a support member  156  including a cylindrical portion  156 A that is fitted on the second small-diameter portion  55  and a flange  156 B having a diameter that is greater than the flange  56 B of the support member  56 . The large-diameter flange  156 B extends perpendicularly to the axis O of the drive shaft  3  from the cylindrical portion  156 A and has a thrust bearing surface  165 B on the rear side thereof. The rollers  125 C are located between the large-diameter flange  156 B and the first race  125 A. The large-diameter flange  156 B has a diameter large enough to cover the outer periphery of the rollers  125 C. In other words, the thrust bearing surface  165 B of the large-diameter flange  156 B serves as a second race such as  25 B of the first embodiment. 
     In the compressor of the third embodiment, the thrust force from the thrust bearing surface  165 B of the large diameter flange  156 B is directly transmitted to the rollers  125 C, so that the second race  25 B as in the first embodiment need not be provided in the second thrust bearing  125  and the number of parts for the compressor may be reduced, accordingly. As a result, the production cost of the compressor may be reduced. The compressor according to the third embodiment offers substantially the same effects as the compressor of the first embodiment. 
     The Fourth Embodiment 
     The following will describe a compressor according to a fourth embodiment of the present invention with reference to  FIG. 7 . The compressor of the fourth embodiment has a support member  256  of a bottomed cylindrical shape. The support member  256  includes a cylindrical portion  256 A and a bottom portion  256 C. The bottom portion  256 C extends from the rear end of the cylindrical portion  256 A toward the axis O of the drive shaft  3 . 
     The bottom portion  256 C has at the center thereof a hole  256 D through which an adjusting screw  257  is screwed. The hole  256 D is coaxially with the axis O of the drive shaft  3 . An adjustment space  256 E is formed between the bottom portion  256 C of the support member  256  and the rear end of the second small-diameter portion  155  of the drive shaft  103 , and the adjustment space  256 E is in communication with the pressure adjusting chamber  21 C via the hole  256 D. 
     The drive shaft  103  of the compressor of the fourth embodiment includes a first small-diameter portion  154  and a second small-diameter portion  155 . An in-shaft axial passage  154 A extends in the second small-diameter portion  155  and the first small-diameter portion  154  frontward from the rear end of the drive shaft  103 . The in-shaft axial passage  154 A is formed with its axis offset from the axis O, so that the in-shaft axial passage  154 A rotates around the axis O of the drive shaft  103 . The rest of the configuration of the fourth embodiment is substantially the same as the first embodiment. 
     In mounting the support member  256  on the second small-diameter portion  155  of the drive shaft  103 , the axial position of the support member  256  relative to the drive shaft  3  is easily adjustable by screwing in or out the adjusting screw  257 . In other words, the adjusting screw  257  is inserted through the bottom portion  256 C to adjust the projection of the support member  256  beyond the one end of the drive shaft  3 . The thrust allowance of the compressor may be thus controlled. 
     The adjusting screw  257  is removed while the swash plate type variable displacement compressor is being assembled. The control pressure chamber  65  and the pressure adjusting chamber  21 C are in communication with each other via the hole  256 D, the adjustment space  256 E, the axial passage  154 A and the radial passage  54 B shown in  FIGS. 1 and 2 . The compressor of the fourth embodiment provides the same effects as the compressor of the first embodiment. 
     The present invention is not limited to the above-described first, second, third and fourth embodiments, but it may be modified in various manners within the scope of the present invention. 
     The present invention is applicable to an air conditioner.