Patent ID: 7891957
Filing Date: 2011-02-22
Classification: F04C

Abstract:
1. A capacity variable type rotary compressor, comprising: a casing having a gas suction pipe configured to be connected to an evaporator and a gas discharge pipe configured to be connected to a condenser; a cylinder fixed in the casing, the cylinder including an inner space at a center thereof that compresses a refrigerant as a rolling piston performs an orbit motion, an inlet penetratingly formed at the inner space and extending in a radial direction that is connected to the gas suction pipe, a vane slit that extends in a radial direction and supports a vane that divides the inner space into a compression chamber and a suction chamber by contacting the rolling piston in a radial direction, a first discharge port that discharges compressed refrigerant gas at a circumferential surface thereof, a first connection hole that is connected with the first discharge port, and a second connection hole that is connected with the inlet; a first bearing plate that covers an upper side of the cylinder first bearing plate including a bypass hole that connects the first connection hole to the second connection hole, a second discharge port that discharges the compressed refrigerant gas discharged through the first discharge port into the casing provided at a middle of the bypass hole, and a valve hole into which a sliding valve is slidably inserted; a second bearing plate that covers a lower side of the cylinder; a first discharge valve and a second discharge valve, respectively, installed at an end of the first and second discharge ports that open and close the first and second discharge ports; a capacity varying device that selectively discharges a part of the compressed refrigerant gas into the inner space of the cylinder; and a back pressure switching device that supplies a back pressure to the capacity varying device so that the capacity varying device opens and closes the bypass hole according to a driving mode of the compressor, wherein the back pressure switching device comprises: