Swash plate type variable displacement compressor

Abstract

In a swash plate type variable displacement compressor, a rear housing has a pressure regulation chamber into which a rear end of a drive shaft body, a projection of a second cylinder block, a second sliding bearing, and a rear end of a second support member project. In the compressor, when a drive shaft is rotated, heat is generated in the drive shaft body, the projection, the second sliding bearing, and the second support member to heat the refrigerant gas in the pressure regulation chamber. Accordingly, in the compressor, temperature of the refrigerant gas in the pressure regulation chamber is hard to drop. Therefore, the pressure of the refrigerant gas flowing from the pressure regulation chamber to the pressure control chamber is varied quickly and a movable body is preferably moved with the pressure in the pressure control chamber.

What is claimed is: 
     
         1 . A swash plate type variable displacement compressor comprising:
 a housing having therein a suction chamber, a discharge chamber, a swash plate chamber, and a plurality of cylinder bores;   a drive shaft rotatably supported in the housing;   a swash plate which is rotatable in the swash plate chamber with the rotation of the drive shaft;   a link mechanism which is disposed between the drive shaft and the swash plate and allows a change in an inclination angle of the swash plate with respect to the direction perpendicular to the axis of the drive shaft;   a plurality of pistons which is reciprocally received in the respective cylinder bores;   a conversion mechanism which converts the rotation of the drive shaft into reciprocal movement of the pistons in the respective cylinder bores in conjunction with the swash plate with a stroke length according to the inclination angle of the swash plate;   an actuator for changing the inclination angle of the swash plate; and   a control mechanism which controls the actuator, wherein   the housing has therein a pressure regulation chamber, the pressure regulation chamber is disposed radially inward of the discharge chamber, which is disposed radially inward of the suction chamber,   the actuator includes a fixed body, a movable body, and a pressure control chamber, wherein the fixed body is fixed on the drive shaft in the swash plate chamber, the movable body is connected to the swash plate and movable relative to the fixed body in the direction of the axis of rotation, and the pressure control chamber is defined by the fixed body and the movable body and the pressure in the pressure control chamber is changed by introducing the pressure in the discharge chamber into the pressure control chamber such that the movable body is moved,   the control mechanism has a control passage and a control valve, the control passage providing communication between the discharge chamber and the pressure control chamber via the pressure regulation chamber, the control valve adjusting an opening of the control passage to vary pressure in the pressure regulation chamber such that the movable body is moved,   at least a part of the control passage is formed in the drive shaft, and the drive shaft projects into the pressure regulation chamber such that the control passage connects the pressure regulation chamber and the pressure control chamber.   
     
     
         2 . The compressor according to  claim 1 , wherein
 the housing has therein a cylinder block and a rear housing, the cylinder block having the cylinder bores, rotatably supporting the drive shaft, the rear housing being connected to the cylinder block through a valve unit and having at least the discharge chamber, wherein   the cylinder block projects into the pressure regulation chamber.   
     
     
         3 . The compressor according to  claim 2 , wherein
 the drive shaft includes a drive shaft body and a cap which is fitted on the drive shaft body and disposed between the drive shaft body and the cylinder block, the drive shaft body and the cap projecting into the pressure regulation chamber.   
     
     
         4 . The compressor according to  claim 3 , wherein
 a radial bearing is provided between the cylinder block and the cap and projects into the pressure regulation chamber.   
     
     
         5 . The compressor according to  claim 3 , wherein a thrust bearing is provided between the cylinder block and the cap. 
     
     
         6 . The compressor according to  claim 1 , wherein
 the suction chamber and the swash plate chamber form a low-pressure chamber;   the control passage includes a high-pressure passage which provides communication between the discharge chamber and the pressure regulation chamber, a low-pressure passage which has the control valve and provides communication between the low-pressure chamber and the pressure regulation chamber, and a pressure-changing passage which is formed in the drive shaft and provides communication between the pressure regulation chamber and the pressure control chamber; and   a part of the pressure-changing passage projects into the pressure regulation chamber together with the drive shaft.