Swash-plate compressor with leakage passages through the discharge valves of the cylinders

A compressor having a cam plate located in a crank chamber and mounted on a drive shaft and a piston coupled to the cam plate and located in a cylinder bore, wherein said cam plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore to vary a capacity of the cylinder bore, said piston compressing a refrigerant gas supplied to the cylinder bore from a separate external circuit by way of a suction chamber and discharging a compressed gas to a discharge chamber, wherein said cam plate is 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 pressure difference between the crank chamber and the cylinder bore, and wherein said cam plate varies a stroke of the piston based on an inclination thereof to control a displacement of the compressor, said compressor comprising:

• a shutter member movable between a first position wherein the shutter member connects the external circuit with the suction chamber and a second position wherein the shutter member disconnects the external circuit from the suction chamber in response to the inclination of the cam plate, whereby said cam plate moves the shutter member to the second position when the cam plate is at the minimum inclined angle position to minimize the displacement of the compressor;
• a release passage for connecting the crank chamber and the suction chamber to deliver the gas from the crank chamber to the suction chamber;
• a supply passage for connecting the discharge chamber and the crank chamber to deliver the gas from the discharge chamber to the crank chamber;
• a circulating passage including the release passage and the supply passage, said circulating passage being defined upon disconnection of the external circuit from the suction chamber;
• a valve plate located between the cylinder bore and a gas chamber, wherein the gas chamber is either one of the suction chamber and the discharge chamber, said valve plate having a port that connects the cylinder bore with the gas chamber and a valve that has open and shut positions for opening and shutting the port, respectively;
• a passage defined between said valve plate and said valve when said valve is shut to connect the cylinder bore with the gas chamber;
• said valve having a surface facing the valve plate;
• said valve plate having a surface facing the valve;
• and
• said passage being formed around the port and between said facing surface of the valve and said facing surface of the valve plate, for enabling sufficient discharge of refrigerant gas and lubricant suspended therein from said cylinder bore to the gas chamber when the cam plate is at the minimum inclined angle position, for said cam plate to move the shutter member to the second position to disconnect the external circuit from the suction chamber.

A tiltable cam plate, variable displacement, piston type compressor for compressing refrigerant gas, wherein the refrigerant is mixed with oil, said compressor comprising:

• a compression chamber, which forms part of a gas path that the refrigerant follows as it moves through the compressor;
• a valved port for intermittently connecting the compression chamber with a part of the gas path that is outside of the compression chamber, said port having a planar area surrounding the port;
• and
• a flexible flap for intermittently contacting the planar area to close the port, wherein either one of a surface of the flap and the planar area has a groove defined therein, the groove forming a restricted passage between the flap and the planar area through which relatively small amounts of refrigerant and oil may pass when the flap is in contact with the planar area.