Patent ID: 8635884

Claim:
A multi-cylinder rotary compressor containing an electric motor unit and a compression mechanism unit in a well-closed container and having an oil stagnant portion that stagnates lubricating oil at an inner bottom of the well-closed container, wherein the compression mechanism unit includes a first cylinder and a second cylinder provided with an intermediate partition plate placed therebetween, having a cylinder chamber into which a low-pressure gas is introduced formed in respective inner diameter portions, and provided with vane rear chambers communicatively connected to the cylinder chambers via a vane groove, an axis of rotation having an eccentric portion contained in the respective cylinder chambers of the first cylinder and the second cylinder and connected to the electric motor unit, an eccentric roller fitted to an eccentric portion of the axis of rotation to eccentrically move inside each of the cylinder chambers with rotation of the axis of rotation, and a vane contained freely movably in the vane groove to partition the cylinder chamber while a tip portion thereof is in contact with a circumferential wall of the eccentric roller, one of the vane rear chambers provided in the first cylinder and the second cylinder includes an elastic body that brings the tip portion of the vane into contact with the circumferential wall of the eccentric roller by providing an elastic force to a rear-end portion of the vane to constantly cause compression operation in the cylinder chamber with the rotation of the axis of rotation, the other vane rear chamber has a sealed structure and includes a pressure switching unit that causes compression operation in the cylinder chamber with the rotation of the axis of rotation by guiding a portion of a high-pressure gas to provide high-pressure back pressure to the rear-end portion of the vane to bring the tip portion of the vane into contact with the circumferential wall of the eccentric roller or holds the tip portion of the vane separated from the circumferential wall of the eccentric roller by guiding the low-pressure gas to provide low-pressure back pressure to the rear-end portion of the vane, the vane receiving the back pressure due to the pressure switching unit is provided with an oiling groove on a side surface thereof, a component of the compression mechanism unit is provided with a lubricating oil communication path that communicatively connects the oiling groove and the oil stagnant portion, and the oiling groove is provided in a position opposite to a portion other than the lubricating oil communication path when the tip portion of the vane receiving the back pressure due to the pressure switching unit is in a top dead center position where the tip portion dips most from the cylinder chamber.