A multi-stage vacuum pump comprising a stator defining multiple pumping chambers is discussed. The stator comprises a plurality of transfer channels for providing a fluid passage from an outlet port of one of the plurality of pumping chambers to an inlet port of a subsequent pumping chamber. Some of the transfer channels comprise two side channel sections on opposing sides of the stator. One of the transfer channels comprises a single side channel section on one side of the stator. The vacuum pump further comprises a gas ballast inlet channel arranged on an other side of the stator to the one side of the stator.

A permanent magnet electric motor includes a shaft extending along a longitudinal axis, wherein the shaft defines a shaft jacket extending along a first direction, a rotor mounted on the shaft, a stator disposed about the rotor. The rotor defines a plurality of longitudinal channels each with the shaft jacket. The longitudinal channels are part of a rotor jacket. The rotor jacket includes a plurality of inlets fluidly interconnecting the shaft jacket and the plurality of the longitudinal channels. The rotor jacket includes an inner edge and an outer edge opposite the inner edge. The rotor jacket includes a plurality of outlets each in fluid communication with the plurality of longitudinal channels. Each of the outlets is closer to the inner edge than to the outer edge of the rotor jacket.

A compressor may include first and second scroll members, a driveshaft, first and second bearings, and first and second Oldham couplings. The scroll members define compression pockets. The first bearing may define a first rotational axis about which the first scroll member rotates. The second bearing may support the second scroll member for rotation about a second rotational axis that is offset from the first rotational axis. The first Oldham coupling may include a first body and a plurality of first keys extending from the first body. The first keys may engage slots formed in the second scroll member. The second Oldham coupling is separate and distinct from the first Oldham coupling. The second Oldham coupling may include a second body and a plurality of second keys extending from the second body. The second keys may engage slots formed in a surface that rotates about the first rotational axis.

The present disclosure relates to a scroll compressor and its lubricating oil supply system. The lubricating oil supply system includes: an oil passage P.sub.1 formed by a core hole extending longitudinally through the crankshaft; an oil pump, whose oil suction port is immersed in the lubricating oil in the oil pool, and the oil outlet is connected to the oil circuit P.sub.1; an oil passage P.sub.3 located in the gap between the upper end surface of the crankshaft and the lower surface of the orbiting scroll; an oil passage P.sub.4 formed by a longitudinal hole in the crankshaft, the longitudinal hole extending downwards from the upper end surface of the crankshaft; an oil passage P.sub.5 formed by a transverse hole in the crankshaft and a gap between the lower edge of the hub of the orbiting scroll and the upper surface of the upper counterweight, the transverse hole extending transversely from the outer peripheral surface of the upper end of the crankshaft to communicate with the longitudinal hole, the opening of the transverse hole on the outer peripheral surface of the upper end of the crankshaft is aligned with the gap between the lower edge of the hub and the upper surface of the upper counterweight; an oil passage P.sub.6 formed by the gap between the outer peripheral surface of the hub and the upright wall of the upper counterweight, and the gap between the outer peripheral surface of the hub and the inner peripheral surface of the center hole of the housing; and an oil passage P.sub.2 formed by an oil return pipe so that the lubricating oil circulates.

A vane rotary compressor includes a roller rotatably supported in a cylinder and including a plurality of vane slots formed along a circumferential direction with back pressure chambers formed at one end of each of the vane slots. A plurality of vanes are slidably supported in the vane slots protruding toward an inner circumferential surface of the cylinder. A compression space formed by the vanes between the roller and the cylinder includes an inlet port and an outlet port formed at both sides of a contact point between the roller and the cylinder. A vane positioned between the inlet port and the outlet port is configured such that a front gap between a front surface of the vane and the inner circumferential surface of the cylinder is smaller than a rear gap between a rear surface of the vane and an inner surface of the back pressure chamber.

A vane rotary compressor includes a roller rotatably supported in a cylinder and including a plurality of vane slots formed along a circumferential direction with back pressure chambers formed at one end of each of the vane slots. A plurality of vanes are slidably supported in the vane slots protruding toward an inner circumferential surface of the cylinder. A compression space formed by the vanes between the roller and the cylinder includes an inlet port and an outlet port formed at both sides of a contact point between the roller and the cylinder. A vane positioned between the inlet port and the outlet port is configured such that a front gap between a front surface of the vane and the inner circumferential surface of the cylinder is smaller than a rear gap between a rear surface of the vane and an inner surface of the back pressure chamber.

A compressor system includes a compressor including a bearing supporting a rotating shaft; a sensor configured to measure an index value correlated with a movement of the rotating shaft being made while the compressor is in operation; and a wear-detecting unit configured to detect a degree of wear of the bearing based on a measured value obtained by the sensor. The bearing is a plain bearing, and has a plurality of air gaps arranged at intervals in a circumferential direction such that wear of the bearing changes a positional relationship between an inner circumferential surface of the bearing and the plurality of air gaps and eventually changes a shape of the inner circumferential surface thereof. The wear-detecting unit detects the degree of wear of the bearing based on a change in the measured value caused by a change in the shape of the inner circumferential surface of the bearing.

A compressor system includes a compressor including a bearing supporting a rotating shaft; a sensor configured to measure an index value correlated with a movement of the rotating shaft being made while the compressor is in operation; and a wear-detecting unit configured to detect a degree of wear of the bearing based on a measured value obtained by the sensor. The bearing is a plain bearing, and has a plurality of air gaps arranged at intervals in a circumferential direction such that wear of the bearing changes a positional relationship between an inner circumferential surface of the bearing and the plurality of air gaps and eventually changes a shape of the inner circumferential surface thereof. The wear-detecting unit detects the degree of wear of the bearing based on a change in the measured value caused by a change in the shape of the inner circumferential surface of the bearing.

A compressor includes a compression mechanism, an electric motor unit, a drive shaft and a housing. A portion of the drive shaft, which is located on one side in an axial direction, is rotatably supported by a main bearing, which is formed integrally in one-piece with or is fixed to a main bearing member of the compression mechanism. Another portion of the drive shaft, which is located on another side in the axial direction, is rotatably supported by a sub-bearing, which is formed integrally in one-piece with or is fixed to an inside of a body portion of a sub-bearing member. The sub-bearing member is formed separately from the housing and is fixed to a bottom surface of a bottom portion of the housing.

A vacuum pump which can decompose depositions by radicals and effectively exhaust them is provided. The vacuum pump including a casing, a stator disposed on an inner side of the casing, and a shaft rotatably supported with respect to the stator and also including a cylindrical rotor rotatably enclosed together with the shaft in the casing, in which an electrode portion, which is a part of a radical generating device that generates radicals, is disposed in the casing.