Variable displacement compressor having refrigerant flowing function in driving shaft

Abstract

Provided is a variable displacement compressor comprising a cylinder block having a plurality of cylinder bores, housing, a drive shaft rotatably supported by the cylinder block, a lug plate, a swash plate being rotated by the lug plate to vary a tilt angle thereof, a sleeve reciprocally moving along the drive shaft, an addition discharge passage for fluid communication between the swash plate chamber and the suction chamber, characterized in that the variable displacement compressor comprises: a communication hole being a part of the addition discharge passage and formed in the drive shaft in its longitudinal direction; and a lateral communication passage formed at the lateral side of the drive shaft to be connected to the communication hole such that the lateral communication passage is opened and closed by reciprocal movement of the sleeve. Therefore, even though the swash plate is at position of the maximum tilt angle, the temperature of the swash plate chamber is prevented from rising by making a smooth refrigerant flow from the swash plate chamber to the suction chamber, thereby maintaining higher lubrication ability.

1 . A variable displacement compressor comprising a cylinder block having a plurality of cylinder bores, a front housing disposed at a front end of the cylinder block to form a swash plate chamber, a drive shaft rotatably supported by the cylinder block, a lug plate fixedly installed at the drive shaft in the swash plate chamber of the front housing, a rear housing having a suction chamber and discharge chamber and being disposed at a rear end of the cylinder block, a swash plate being rotated by the lug plate to vary a tilt angle thereof, pistons coupled to the swash plate to be reciprocally accommodated in the cylinder bores, a sleeve reciprocally moving along the drive shaft, a spring elastically supporting the sleeve around the drive shaft, an addition discharge passage for fluid communication between the swash plate chamber and the suction chamber, characterized in that the variable displacement compressor comprises: a communication hole being a part of the addition discharge passage and formed in the drive shaft in its longitudinal direction; and a lateral communication passage formed at the lateral side of the drive shaft to be connected to the communication hole such that the lateral communication passage is opened and closed by reciprocal movement of the sleeve. 
     
     
         2 . The variable displacement compressor according to  claim 1 , wherein the sleeve is moved at more than a predetermined angle of the swash plate to open the communication passage. 
     
     
         3 . The variable displacement compressor according to  claim 1 , wherein the addition discharge passage includes a first separation hole formed through the lug plate, a second separation hole formed in the lug plate to connect the first separation hole and the communication hole and a connection hole formed in the drive shaft to be connected to the separation hole. 
     
     
         4 . The variable displacement compressor according to  claim 2 , wherein the addition discharge passage includes a first separation hole formed through the lug plate, a second separation hole formed in the lug plate to connect the first separation hole and the communication hole, and a connection hole formed in the drive shaft to be connected to the separation hole.