Variable displacement swash plate type compressor

Abstract

A variable displacement swash plate type compressor includes an actuator. The actuator has a lug member, a movable body that is rotatable integrally with a swash plate and is capable of changing an inclination angle of the swash plate by moving in the direction of an driving axis, and a control pressure chamber that is defined by the lug member and the movable body and moves the movable body by changing its internal pressure by a control mechanism. An acting portion that is capable of pressing the swash plate by the pressure in the control pressure chamber is formed at the movable body, and an acted portion that abuts on and is pressed by the acting portion is formed at the swash plate

1 . A variable displacement swash plate type compressor comprising: a housing in which a swash plate chamber and a cylinder bore are formed; a drive shaft that is rotatably supported by the housing; a swash plate that is rotatable in the swash plate chamber by rotation of the drive shaft; a link mechanism that is provided between the drive shaft and the swash plate and permits change of an inclination angle of the swash plate with respect to a direction perpendicular to a driving axis of the drive shaft; a piston that is reciprocally accommodated in the cylinder bore; a conversion mechanism that reciprocates the piston in the cylinder bore at a stroke corresponding to the inclination angle by rotation of the swash plate; an actuator capable of changing the inclination angle; and a control mechanism that controls the actuator,
 wherein the link mechanism has a lug member that is fixed to the drive shaft in the swash plate chamber and a transmission member that transmits rotation of the lug member, to the swash plate,   an insertion hole that slides on an outer circumference of the drive shaft in accordance with the change of the inclination angle is formed through the swash plate,   the swash plate is guided by the link mechanism and the insertion hole in a direction of the driving axis and in a direction of the inclination angle to thereby change the inclination angle,   the actuator has the lug member, a movable body that is rotatable integrally with the swash plate and is capable of changing the inclination angle by moving in the direction of the driving axis, and a control pressure chamber that is defined by the lug member and the movable body and moves the movable body by changing its internal pressure by the control mechanism,   an acting portion that is capable of pressing the swash plate by the pressure in the control pressure chamber is formed at the movable body, and   an acted portion that abuts on and is pressed by the acting portion is formed at the swash plate.   
     
     
         2 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the drive shaft is inserted through the movable body, and the movable body is capable of being fitted to the lug member.   
     
     
         3 . The variable displacement swash plate type compressor according to  claim 2 ,
 wherein the movable body has a movable cylindrical portion that is formed into a cylindrical shape and coaxial with the driving axis, and   the lug member has a fixed cylindrical portion that is formed into a cylindrical shape and coaxial with the driving axis at an outer circumferential side of the movable cylindrical portion to thereby provide the control pressure chamber in the movable cylindrical portion.   
     
     
         4 . The variable displacement swash plate type compressor according to  claim 3 ,
 wherein a first seal member that seals the control pressure chamber is provided between the movable cylindrical portion and the drive shaft, and   a second seal member that seals the control pressure chamber is provided between the movable cylindrical portion and the fixed cylindrical portion.   
     
     
         5 . The variable displacement swash plate type compressor according to  claim 3 ,
 wherein a thrust bearing that receives a thrust force which acts on the piston is provided between the housing and the lug member, and   the movable cylindrical portion is smaller in diameter than the thrust bearing and capable of advancing to an inner side of the thrust bearing.   
     
     
         6 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein a top-dead-center corresponding portion for positioning the piston at its top dead center is defined in the swash plate, and   the acting portion and the acted portion are located eccentrically toward the top-dead-center corresponding portion from the driving axis.   
     
     
         7 . The variable displacement swash plate type compressor according to  claim 6 ,
 wherein the acting portion comes into point-contact or line-contact with the acted portion at an operative position, and   the operative position moves toward the driving axis as the inclination angle decreases.   
     
     
         8 . The variable displacement swash plate type compressor according to  claim 6 ,
 wherein the acting portion has an acting surface that extends in the direction perpendicular to the driving axis, and   the acted portion has a protrusion that protrudes from the swash plate and abuts on the acting surface.   
     
     
         9 . The variable displacement swash plate type compressor according to  claim 7 ,
 wherein a top-dead-center corresponding portion for positioning the piston at its top dead center is defined in the swash plate,   the movable body has a movable cylindrical portion that is formed into a cylindrical shape and coaxial with the driving axis, and   the acting portion protrudes from the movable cylindrical portion toward the top-dead-center corresponding portion.   
     
     
         10 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the swash plate has a swash plate main body that is formed with the insertion hole and the acted portion that is integrally formed with the swash plate main body.   
     
     
         11 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the swash plate has a swash plate main body that is formed with the insertion hole and the acted portion that is fixed to the swash plate main body.   
     
     
         12 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein a suction chamber and a discharge chamber are formed in the housing, and   the suction chamber and the swash plate chamber communicate with each other.   
     
     
         13 . The variable displacement swash plate type compressor according to  claim 12 ,
 wherein the control mechanism has a control passage that provides communication between the control pressure chamber and the suction chamber and/or the discharge chamber and a control valve that is capable of regulating an opening degree of the control passage, and   at least a part of the control passage is formed in the drive shaft.   
     
     
         14 . The variable displacement swash plate type compressor according to  claim 13 ,
 wherein a pressure regulation chamber that communicates with the control pressure chamber through the control passage and allows a pressure therein to be changed by the control valve is formed between the housing and one end of the drive shaft, and   a third seal member that seals the pressure regulation chamber is provided between the housing and the drive shaft.