Patent ID: 7438540

Claim:
A two-stage rotary compressor in which a motor-drive element and a rotary compressing element driven by said motor-drive element are provided on the upper and lower portions respectively in a closed vessel, said two-stage rotary compressor comprising: a low stage side rotary compressing element and a high stage side rotary compressing element that are positioned on upper and lower sides of the rotary compressing element, respectively, whereby an intermediate pressure refrigerant gas compressed by said low stage side rotary compressing element is discharged into said closed vessel, the intermediate pressure refrigerant gas discharged into the closed vessel is taken outside the closed vessel to be cooled and then the cooled intermediate pressure refrigerant gas is supplied to said high stage side rotary compressing element to be compressed to high pressure and the high pressure refrigerant gas is discharged outside said closed vessel; a lower supporting member that is attached to a lower side of said high stage side rotary compressing element, said lower supporting member including: a bearing portion at the center of the lower supporting member for supporting a lower end portion of a rotating shaft, which is rotated by said motor-drive element, wherein a step is provided between the lower end surface of the bearing portion and a lower end surface of said lower supporting member, a muffling chamber surrounding an outer circumference of the bearing portion, and a cover plate that is attached to the lower side of said lower supporting member for closing an opening surface of said muffling chamber; and a gas seal including: a concave groove disposed on a lower end surface of said bearing portion in its circumferential direction, an O ring disposed in said concave groove, and a gasket that is interposed in a connection .portion between said lower supporting member and said cover plate, wherein the gasket has a same thickness or a slightly smaller thickness than the step.