Valve arrangement at the discharge chamber of a variable displacement compressor

A compressor having a crank chamber, a cylinder bore, a suction chamber and a discharge chamber, the compressor comprising a drive shaft extending into the crank chamber, a cam plate mounted on the drive shaft within the crank chamber and a piston coupled to the cam plate and located in the cylinder bore, wherein said cam plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore, said piston compressing gas supplied to the cylinder bore from a separate external circuit by way of the suction chamber and discharging the compressed gas to the external circuit by way of the discharge chamber, said;

• said cam plate being tiltable between a maximum inclined angle position and a minimum inclined angle position with respect to a plane perpendicular to an axis of the drive shaft according to a difference between the pressure in the crank chamber and the pressure in the cylinder bore, wherein said piston moves by a stroke based on the inclination of the cam plate to control the displacement of the compressor;
• the compressor further comprising:
• a supply passage for connecting the discharge chamber with the crank chamber to deliver the gas from the discharge chamber to the crank chamber;
• a release passage for connecting the crank chamber with the suction chamber to deliver the gas from the crank chamber to the suction chamber;
• control means disposed midway along the supply passage for adjusting the amount of the gas introduced into the crank chamber from the discharge chamber through the supply passage to control the pressure in the crank chamber;
• a discharge passage for connecting the discharge chamber with the external circuit;
• a valve located in the discharge passage, said valve having an upstream side and a downstream side, said valve selectively connecting and disconnecting the discharge chamber with the external circuit based on a difference between the pressure acting on the upstream side of the valve and the pressure acting on the downstream side of the valve, said valve disconnecting the discharge chamber from the external circuit when the cam plate is at the minimum inclined angle position to minimize the displacement of the compressor;
• and
• a discharge muffler for preventing pulsation caused by the flow of the gas discharged from the cylinder bore to the discharge chamber, wherein said discharge passage is defined in the discharge muffler.

A compressor for compressing gas supplied from an external circuit and discharging the compressed gas to the external circuit, the compressor comprising:

• a pair of housings having respective end faces secured to one another;
• a crank chamber, a cylinder bore and a discharge chamber defined by the housings;
• a drive shaft supported by the housings;
• a cam plate located in the crank chamber and mounted on the drive shaft, wherein the cam plate is inclined with respect to a plane perpendicular to an axis of the drive shaft according to the pressure in the crank chamber;
• a piston coupled to the cam plate and located in the cylinder bore, wherein the cam plate converts rotation of the drive shaft to reciprocating movement of the piston within the cylinder bore, whereby the piston compresses gas supplied from the external circuit and discharges the compressed gas to the discharge chamber, and the piston moves by a stroke based on the inclination of the cam plate to control the displacement of the compressor;
• and
• a valve between the discharge chamber and the external circuit, the valve having a flange clamped by the end faces of the housings to secure the valve to the housings, the valve having an upstream side and a downstream side, wherein the valve selectively connects and disconnects the discharge chamber with the external circuit based on a difference between the pressure acting on the upstream side of the valve and the pressure acting on the downstream side of the valve.