Swash plate type variable displacement compressor

Abstract

A swash plate type variable displacement compressor includes a housing, a drive shaft, a piston, a lug plate, a swash plate, a hinge mechanism provided between the lug plate and the swash plate, and a control mechanism. The hinge mechanism includes a restraining hinge element that is located on a suction side with respect to a first imaginary plane that includes a top position of the swash plate corresponding to the top dead center position of the piston and the axis of the drive shaft for restraining the lug plate and the swash plate from rotating relative to each other and the swash plate to move away from the lug plate. The hinge mechanism further includes a non-restraining hinge element that is located on a discharge side with respect to the first imaginary plane for not restraining the swash plate from moving away from the lug plate.

1 . A swash plate type variable displacement compressor for compressing a refrigerant, comprising: 
 a housing defining therein a cylinder bore, a crank chamber, a suction chamber and a discharge chamber;    a piston reciprocatably accommodated in the cylinder bore and defining a compression chamber in the cylinder bore;    a drive shaft driven by an external drive source and rotatably supported by the housing;    a lug plate supported by the drive shaft in the crank chamber so as to rotate with the drive shaft;    a swash plate supported by the drive shaft in the crank chamber;    a hinge mechanism provided between the lug plate and the swash plate, the swash plate being rotatable with and inclinable relative to the drive shaft through the lug plate and the hinge mechanism for reciprocating the piston through shoes; and    a control mechanism operable to control a pressure in the crank chamber thereby to vary an amount of the refrigerant discharged from the compression chamber into the discharge chamber by the reciprocation of the piston based on an inclination angle of the swash plate,    wherein the hinge mechanism includes a restraining hinge element that is located on a suction side with respect to a first imaginary plane that includes a top position of the swash plate corresponding to a top dead center position of the piston and an axis of the drive shaft for restraining the lug plate and the swash plate from rotating relative to each other and the swash plate to move away from the lug plate, the hinge mechanism further including a non-restraining hinge element that is located on a discharge side with respect to the first imaginary plane for not restraining the swash plate from moving away from the lug plate.    
   
   
       2 . The swash plate type variable displacement compressor according to  claim 1 , wherein the restraining hinge element includes a support arm that is provided on one of the lug plate and the swash plate and that has a guide hole with an inner circumferential surface and a guide pin that is provided on the other one of the lug plate and the swash plate and that has a spherical portion for sliding in the guide hole.  
   
   
       3 . The swash plate type variable displacement compressor according to  claim 1 , wherein the non-restraining hinge element is provided so as not to restrain the lug plate and the swash plate from rotating relative to each other.  
   
   
       4 . The swash plate type variable displacement compressor according to  claim 3 , wherein the non-restraining hinge element includes a first guide surface that is provided on one of the lug plate and the swash plate facing toward the other one of the lug plate and the swash plate and a second guide surface that is provided on the other one of the lug plate and the swash plate facing toward the first guide surface, the second guide surface being contactable with the first guide surface.  
   
   
       5 . The swash plate type variable displacement compressor according to  claim 1 , wherein the hinge mechanism is located on a side of the top position of the swash plate with respect to a second imaginary plane that includes the axis of the drive shaft and is perpendicular to the first imaginary plane, a surface of the swash plate that faces toward the lug plate providing a receiving surface that is located on the suction side with respect to the first imaginary plane and on a side opposite to the top position with respect to the second imaginary plane for contacting with the lug plate when the swash plate is inclined at a maximum inclination angle thereby to regulate the maximum inclination angle of the swash plate.  
   
   
       6 . The swash plate type variable displacement compressor according to  claim 5 , wherein the receiving surface is formed on a weight portion that is provided in the swash plate.  
   
   
       7 . The swash plate type variable displacement compressor according to  claim 5 , wherein the receiving surface is located at a position within a range where the receiving surface is contactable with the lug plate, which is furthest from the axis of the drive shaft.  
   
   
       8 . The swash plate type variable displacement compressor according to  claim 1 , wherein the drive shaft is constantly driven while the external drive source is running.  
   
   
       9 . The swash plate type variable displacement compressor according to  claim 1 , wherein the swash plate has an elongated hole with parallel facing surfaces for receiving an outer circumferential surface of the drive shaft.  
   
   
       10 . The swash plate type variable displacement compressor according to  claim 1 , wherein the control mechanism includes a supply passage for connecting the discharge chamber to the crank chamber, a bleed passage for connecting the crank chamber to the suction chamber and a displacement control valve disposed in the supply passage.