Variable displacement swash plate compressor

Abstract

A variable displacement swash plate compressor includes a control pressure chamber and a displacement control valve that controls the pressure of the control pressure chamber. The displacement control valve includes an electromagnetic solenoid, a driving force transmission member, a valve body, and a pressure sensing mechanism. An accommodation chamber accommodates the pressure sensing. A valve chamber accommodates the valve body having a valve opening degree determined by an urging force applied to the valve body through the driving force transmission member and by an urging force applied to the valve body by the expansion and contraction of the pressure sensing mechanism. The valve body and the pressure sensing mechanism form a valve unit. When the electromagnetic solenoid is deactivated, the pressure of the accommodation chamber acts on a back surface of the pressure sensing mechanism so that a force in the open direction is applied to the valve unit.

1 . A variable displacement swash plate compressor comprising:
 a housing including a discharge pressure region, of which pressure is a discharge pressure, and a suction pressure region, of which pressure is a suction pressure;   a rotation shaft supported by the housing;   a swash plate accommodated in the housing, wherein the swash plate rotates when receiving driving force from the rotation shaft and inclines relative to the rotation shaft at an inclination angle that is variable;   a piston engaged with the swash plate;   a movable body coupled to the swash plate and adapted to vary the inclination angle of the swash plate;   a control pressure chamber that is defined by the movable body and adapted to move the movable body in an axial direction of the rotation shaft when control gas drawn into the control pressure chamber changes pressure of the control pressure chamber;   a discharge passage extending from the control pressure chamber to the suction pressure region; and   a displacement control valve adapted to control the pressure of the control pressure chamber, wherein   when the pressure of the control pressure chamber approaches the discharge pressure, the movable body moves toward one axial end of the rotation shaft and increases the inclination angle of the swash plate,   when the pressure of the control pressure chamber approaches the suction pressure, the movable body moves toward the other axial end of the rotation shaft and decreases the inclination angle of the swash plate,   the piston reciprocates with a stroke that is in accordance with the inclination angle of the swash plate,   the displacement control valve includes:
 an electromagnetic solenoid; 
 a driving force transmission member driven by the electromagnetic solenoid; 
 a valve body adapted to move in an open direction and a close direction, which is opposite to the open direction, to adjust an opening amount of the discharge passage; 
 a pressure sensing mechanism adapted to expand and contract in movement directions of the valve body in accordance with the suction pressure, wherein the pressure sensing mechanism and the driving force transmission member are located at opposite sides of the valve body; 
 a solenoid housing accommodating the electromagnetic solenoid; and 
 a valve housing accommodating the valve body and the pressure sensing mechanism, 
   the valve housing includes an accommodation chamber, which accommodates the pressure sensing mechanism and is in communication with the control pressure chamber, and a valve chamber, which accommodates the valve body and is in communication with the suction pressure region,   the valve body has a valve opening degree that is determined by an urging force applied to the valve body through the driving force transmission member when the electromagnetic solenoid is activated and by an urging force applied to the valve body by the expansion and contraction of the pressure sensing mechanism in accordance with the suction pressure,   the valve body and the pressure sensing mechanism are formed integrally to form a valve unit,   when the electromagnetic solenoid is deactivated, the pressure of the accommodation chamber acts on a back surface of the pressure sensing mechanism that is opposite to the driving force transmission member so that a force in the open direction is applied to the valve unit.   
     
     
         2 . The variable displacement swash plate compressor according to  claim 1 , wherein the displacement control valve includes a valve open spring that urges the valve unit in the valve open direction. 
     
     
         3 . The variable displacement swash plate compressor according to  claim 1 , wherein the displacement control valve includes a guide portion that guides the valve unit in the movement directions of the valve body. 
     
     
         4 . The variable displacement swash plate compressor according to  claim 1 , wherein the piston includes a double-headed piston. 
     
     
         5 . The variable displacement swash plate compressor according to  claim 1 , wherein the rotation shaft receives rotational driving force from an external driving source through a clutchless power transmission.