Variable displacement swash plate type compressor

Abstract

A variable displacement swash plate type compressor includes a housing. The housing includes a first cylinder bore and a second cylinder bore. The second cylinder bore has a smaller diameter than the first cylinder bore. A first thrust bearing is provided between one end side of a drive shaft and the housing so as to receive a thrust force acting on the drive shaft in a direction toward the one end side, and a second thrust bearing is provided between an opposite end side of the drive shaft in a direction toward the opposite end side. A second spring constant of the second thrust bearing is greater than a first spring constant of the first thrust bearing.

1 . A variable displacement swash plate type compressor comprising:
 a drive shaft;   a housing that rotatably supports the drive shaft, the housing including a first cylinder bore formed at one end side of the drive shaft, a second cylinder bore formed at an opposite end side of the drive shaft, and a swash plate chamber formed between the first cylinder bore and the second cylinder bore;   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 in a direction perpendicular to an axis of the drive shaft;   a double-headed piston that defines a first compression chamber in the first cylinder bore and defines a second compression chamber in the second cylinder bore;   a conversion mechanism that reciprocates the piston in the first and second cylinder bores at a stroke corresponding to the inclination angle along with the rotation of the swash plate;   an actuator capable of changing the inclination angle; and   a control mechanism that controls the actuator,   wherein the second cylinder bore has a smaller diameter than the first cylinder bore,   a first thrust bearing is provided between the one end side of the drive shaft and the housing so as to receive a thrust force acting on the drive shaft in a direction toward the one end side,   a second thrust bearing is provided between the opposite end side of the drive shaft and the housing so as to receive a thrust force acting on the drive shaft in a direction toward the opposite end side, and   a second spring constant of the second thrust bearing is greater than a first spring constant of the first thrust bearing.   
     
     
         2 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the housing includes a first cylinder block disposed at the one end side of the drive shaft and a second cylinder block disposed at the opposite end side of the drive shaft, the first cylinder block having the first cylinder bore, the second cylinder block having the second cylinder bore,   a first annular portion formed into an annular shape around the axis of the drive shaft is disposed at the one end side of the drive shaft,   a second annular portion formed into an annular shape around the axis of the drive shaft is disposed at the opposite end side of the drive shaft,   the first thrust bearing is disposed between the first cylinder block and the first annular portion,   a region where the first thrust bearing is supported by the first annular portion and a region where the first thrust bearing is supported by the first cylinder block are radially shifted from each other,   the second thrust bearing is disposed between the second cylinder block and the second annular portion, and   a region where the second thrust bearing is supported by the second annular portion and a region where the second thrust bearing is supported by the second cylinder block are radially shifted from each other.   
     
     
         3 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the housing includes a first cylinder block disposed at the one end side of the drive shaft and a second cylinder block disposed at the opposite end side of the drive shaft, the first cylinder block having the first cylinder bore, the second cylinder block having the second cylinder bore,   a first annular portion formed into an annular shape around the axis of the drive shaft is disposed on the one end side of the drive shaft,   a second annular portion formed into an annular shape around the axis of the drive shaft is disposed at the opposite end side of the drive shaft,   the first thrust bearing is disposed between the first cylinder block and the first annular portion,   the second thrust bearing is disposed between the second cylinder block and the second annular portion,   the first thrust bearing includes a one end-side first race that faces the first cylinder block, a one end-side second race that faces the first annular portion, and a plurality of first rolling elements that is held between the one end-side first race and the one end-side second race,   the second thrust bearing includes an opposite end-side first race that faces the second cylinder block, an opposite end-side second race that faces the second annular portion, and a plurality of second rolling elements that is held between the opposite end-side first race and the opposite end-side second race, and   a thickness of at least one of the opposite end-side first race and the opposite end-side second race is greater than a thickness of the one end-side first race and the one end-side second race.   
     
     
         4 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein an outer diameter of the second thrust bearing is smaller than an outer diameter of the first thrust bearing.   
     
     
         5 . The variable displacement swash plate type compressor according to  claim 1 ,
 wherein the actuator includes a partition body that is provided on the drive shaft, a connecting portion that is connected to the swash plate, a movable body that is movable in the swash plate chamber in a direction of the axis of the drive shaft, and a control pressure chamber that is defined by the partition body and the movable body and moves the movable body so as to increase the inclination angle by introducing refrigerant from a discharge chamber, and   the actuator is disposed on the side of the second cylinder bore with respect to the swash plate in the swash plate chamber.