A rotary compressor is provided that may include a rotation preventing key between a roller and a rotary shaft, the roller being a separable-type roller assembled into the rotary shaft. The rotation preventing unit may constrain rotation of the roller and allow axial movement of the roller with respect to the rotary shaft. Thus, axial movement of the roller along the rotary shaft may be suppressed or prevented, and thus, friction loss and abrasion between the roller and a main bearing or between the roller or a sub bearing may be suppressed or prevented.

Technologies are generally described for clearance adjustments in twin-screw pump assemblies. A twin-screw pump assembly may include a conically shaped portion of a drive shaft enveloped by a bushing. For clearance adjustment, both clamping nuts of the drive shaft, which provide pretention to the bushing and secure an axial position of a threaded screw to the drive shaft, may be removed on the flow side of the pump assembly and the bushing loosened to adjust the angularity between bushing and drive shaft. The bushing may then be pushed over the conically shaped portion and both clamping nuts re-assembled. In some examples, a clamping nut of the driven shaft may be designed and used as removal/loosening tool for the drive shaft bushing.

A screw compressor includes a male rotor and a female rotor enclosed in a casing inside which they counter-rotate, to drive the male rotor from a motor, a gas passes through an intake duct created between the two rotors, and the rotation closes this intake duct and the compressed gas is pushed towards a delivery. Each rotor includes a rotation shaft which rotates in the case due to special bearings which is surrounded by helical propellers which engage each other, the propellers being made to reduce progressively the space between rotors and casing, so that the gas sucked in by the suction duct compresses in the direction of the delivery. The helical propellers are made of a polymeric material.

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.

Durability of a vacuum pump is prevented from degrading by suppressing abrasion of a rotor and a side plate. The vacuum pump has a hollow cylinder chamber S having an opening at an end portion of a casing body, a rotor which is rotationally driven in the cylinder chamber S, a side plate for blocking the opening of the cylinder chamber S, and a pump cover which is disposed at the opposite side to the rotor so as to sandwich the side plate between the pump cover and the rotor, and the side plate is provided with an intercommunication port which confronts a shaft hole of the rotor and intercommunicates with a space between the side plate and the pump cover.

A compressor includes a drive shaft having a main shaft and an eccentric portion, and a compression mechanism having a fitted tubular portion into which a fitted shaft portion of the drive shaft is slidably fitted. The fitted shaft portion has first and second sliding surfaces formed as portions of an outer peripheral surface in the circumferential direction. The second sliding surface has a smaller axial width than the first sliding surface. A gap is adjacent to the second sliding surface into which a lubricating oil flows. An oil retainer is configured as a boundary portion between the first sliding surface and the gap to keep the lubricating oil in the gap from flowing out toward an end surface of the fitted shaft portion. The boundary portion has a central portion that protrudes further toward the first sliding surface than an end of the boundary portion in a lubricating oil flow-out direction.

A compressor is provided and may include a shell, a hub, an insert, and at least one collar. The hub may be disposed within the shell and define an axis of rotation. The hub may include an axially extending aperture. The insert may be disposed within the aperture. The at least one collar may be disposed about the hub.

A compressor includes a drive shaft having a main shaft and an eccentric portion, and a compression mechanism having a fitted tubular portion into which a fitted shaft portion of the drive shaft is fitted. The fitted shaft portion and the fitted tubular portion slide relative to each other with an oil film interposed between. The fitted shaft portion has first and second sliding surfaces formed as portions of an outer peripheral surface in the circumferential direction. The second sliding surface has a smaller axial width than the first sliding surface. A sliding portion between the fitted shaft portion and the fitted tubular portion has a gap adjacent to the second sliding surface into which a lubricating oil flows, and an oil retainer to keep the lubricating oil in the gap from flowing out toward an end surface of the fitted shaft portion.

A vane pump includes: a casing forming a pump chamber therein; a rotor arranged inside the casing to rotate eccentrically with respect to the casing; and a plurality of vanes configured to rotate with the rotor and slide on an inner side surface of the casing. At least one of Formula (1): l≤(b/a)×k and Formula (2): l≤(c/a)×j is satisfied, where “a” represents a height of the pump chamber, “b” represents a height of the rotor, “c” represents a height of the vane in a rotation axis direction of the rotor, and where “l” represents a linear expansion coefficient of the casing in the rotation axis direction, “k” represents a linear expansion coefficient of the rotor in the rotation axis direction, and “j” represents a linear expansion coefficient of the vane in the rotation axis direction.

Provided is a co-rotating scroll compressor comprising a synchronous drive mechanism that can achieve a long life. The compressor comprises a driving side scroll member (90) driven to rotate about a driving side rotation axis CL1, a driven side scroll member (70) driven to rotate about a driven side rotation axis CL2, a hollowed drive shaft (6) that is connected to the driving side scroll member (90), and driven by a motor (5) to rotate, and a driven shaft (20) that is disposed inside the drive shaft (6), and has one end connected to the drive shaft (6) via a first flexible coupling (21) and the other end connected to the driven side scroll member (70) via a second flexible coupling (22).