Compressor and refrigeration cycle apparatus

A compressor comprising:

• a hermetically sealed container;
• an electric motor;
• a low-stage compression mechanism unit driven by a crankshaft fitted into the electric motor and configured to compress low-pressure refrigerant to intermediate pressure;
• a high-stage compression mechanism unit driven by the crankshaft and configured to compress intermediate-pressure refrigerant discharged by the low-stage compression mechanism unit to high pressure;
• and an intermediate partition plate provided between the low-stage compression mechanism unit and the high-stage compression mechanism unit, the electric motor, the low-stage compression mechanism unit, the high-stage compression mechanism unit, and the intermediate partition plate being accommodated in an internal space of the hermetically sealed container, wherein
• the high-stage compression mechanism unit includes
• a high-stage cylinder block with a cylindrical shape,
• a high-stage rolling piston located in an internal space of the high-stage cylinder block,
• a high-stage vane located in the high-stage cylinder block such that the high-stage vane is slidable in a radial direction of the high-stage cylinder block, the high-stage vane being configured to partition, along with the high-stage rolling piston, the internal space of the high-stage cylinder block into a high-stage suction chamber into which refrigerant is sucked and a high-stage compression chamber in which refrigerant is compressed, and
• a high-stage refrigerant supply passage serving as a path through which refrigerant compressed in the high-stage compression chamber is discharged to a space external to the hermetically sealed container, the high-stage refrigerant supply passage being a space surrounded by a high-stage bearing and a high-stage discharge muffler, the high-stage bearing supporting the crankshaft and being adjacent to the high-stage cylinder block in an axial direction of the high-stage cylinder block, the high-stage discharge muffler being adjacent to the high-stage bearing in an axial direction of the high-stage cylinder block,
• the high-stage cylinder block includes a high-stage back pressure chamber, the high-stage back pressure chamber being a space surrounded by an outer circumferential surface of the high-stage cylinder block, the high-stage bearing, the intermediate partition plate, and the high-stage vane,
• the high-stage back pressure chamber is a space separate from the internal space of the hermetically sealed container, and communicates with the high-stage refrigerant supply passage,
• in the high-stage bearing, a high-stage suction hole is formed and a tip end of a refrigerant suction pipe is inserted into the high-stage suction hole,
• the low-stage compression mechanism unit includes
• a low-stage cylinder block with a cylindrical shape,
• a low-stage rolling piston located in an internal space of the low-stage cylinder block, and
• a low-stage vane located in the low-stage cylinder block such that the low-stage vane is slidable in a radial direction of the low-stage cylinder block, the low-stage vane being configured to partition, along with the low-stage rolling piston, the internal space of the low-stage cylinder block into a low-stage suction chamber into which refrigerant is sucked by increasing a volume of the low-stage suction chamber and a low-stage compression chamber in which refrigerant is compressed by decreasing a volume of the low-stage compression chamber,
• the low-stage cylinder block includes a low-stage back pressure chamber, the low-stage back pressure chamber being a space surrounded by an outer circumferential surface of the low-stage cylinder block, a low-stage bearing, the intermediate partition plate, and the low-stage vane, the low-stage bearing supporting the crankshaft and being adjacent to the low-stage cylinder block in an axial direction of the low-stage cylinder block, and
• the low-stage back pressure chamber is a space separate from the internal space of the hermetically sealed container, and communicates with the high-stage refrigerant supply passage-not via the internal space of the hermetically sealed container, wherein the low-stage compression mechanism unit, the high-stage compression mechanism unit, and the intermediate partition plate are layered from the bottom of the compressor in the order of the high-stage compression mechanism unit, the intermediate partition plate, and the low-stage compression mechanism unit.