Variable capacity wobble plate compressor

Abstract

A variable capacity wobble plate compressor in which pressure in a crankcase accomodating a wobble plate is controlled by a pressure-control valve disposed across a communication passage connecting the crankcase and a suction chamber, whereby the delivery quantity or capacity is varied with a change in the inclination angle of the wobble plate depending on the pressure in the crankcase. The pressure-control valve comprises bellows variable in length with a change in the magnituted of suction pressure, a valve body attached to one end of the bellows, a first movable member attached to the other end of the bellows, a first spring urging the valve body in the closing direction, a second movable member which is brought into or out of urging contact with the first movable member in response to at least a change in the discharge pressure, and a second spring interposed between the second movable member and a spring seat. When the discharge pressure is higher than a predetermined value, the second movable member is biased away from the first movable member by the discharge pressure against at least the force of the second spring. When the discharge pressure is lower than the predetermined value, the second movable member is urged against the first movable member by at least the force of the second spring against the discharge pressure to urge the valve body in the closing direction via the first movable member, the first spring and the bellows.