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 tubular portion has first and second sliding surfaces formed as portions of an inner peripheral surface of the fitted tubular portion 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 tubular portion.

An electric compressor includes a housing including a compression part housing, a shaft support housing, and a motor housing fastened by a plurality of fastening members. A peripheral wall has a plurality of thick-walled portions that protrudes inwardly in a radial direction and through which their associated fastening members are inserted. The fixed scroll base plate has a plurality of protruded portions each protruding outwardly in the radial direction and disposed between the thick-walled portions in a circumferential direction. The fixed scroll base plate has a plurality of pillar portions each extending from the protruded portions toward the shaft support housing in the axial direction and spaced from each other in the circumferential direction. The elastic plate is held at a plurality of spots by the plurality of pillar portions and the shaft support housing.

A mud motor and a drill string having the mud motor. The mud motor includes a stator and a rotor. A lining between the stator and the rotor includes fibers forming a fiber pattern. The lining is a coating of at least one of a lobed inner surface of the stator and a lobed outer surface of the rotor.

The present disclosure may provide a compressor in which an outer circumferential side cross-sectional area of a vane slot is formed to be smaller than an inner circumferential side cross-sectional area thereof to decrease an area receiving a force in a roller direction by a vane so as to reduce a contact force between the roller and the vane, and a gas accommodation portion capable of selectively forming a suction pressure and an intermediate pressure is formed between the vane and the vane slot to appropriately control a contact force between the vane and the roller, and a contact surface of the vane facing the roller is broadly formed at a side of a compression chamber to appropriately reduce a contact force between the roller and the vane, and a space portion forming a discharge pressure is formed at least either one side of a side surface of the vane and a cylinder corresponding thereto to decrease a side directional reaction force applied to the vane, thereby reducing a mechanical friction loss between the vane and the cylinder.

A variable displacement rotary vane pump. The pump has a pump body, a rotor with vanes that rotates inside the pump body around a rotation axis, an oscillating stator arranged in an eccentric position around the rotor, a fulcrum for the rotation of the oscillating stator with respect to the pump body, and adjusting means for adjusting the displacement of the pump. The adjusting means act on the oscillating stator to move it with respect to the rotor and the pump body. The fulcrum is integrally formed with the oscillating stator and is housed in a recess formed in the pump body. The pump has a sliding element between the fulcrum and the recess. The sliding element is at least partially free to rotate within the recess.

A rotary compressor or pump has a cam with a plurality of lobes mechanically engaging a plurality of pistons. The lobes urge the pistons from an open to a closed position within a piston void, the closure of the piston into the piston void creating compression or pressure of a material. Each piston is linked to another piston, and as one piston is closed by the cam, the other piston is opened by a linkage.

A scroll compressor includes a fixed scroll, a movable scroll, a main bearing housing and an axial compliance mounting mechanism. The fixed scroll is engaged with the movable scroll to compress a working fluid. The main bearing housing has a bearing surface for supporting a movable scroll end plate. The fixed scroll is fixedly connected to a connecting portion of the main bearing housing by the axial compliance mounting mechanism so that the fixed scroll can move in the axial direction by a predetermined distance. The fixed scroll further includes a flange extending radially outward from a circumferential wall portion, having an axial geometric center position between a first surface and a second surface and positioned such that the axial geometric center position is closer to the movable scroll end plate than the axial middle position thereof. The structure can prevent or reduce damage to the axial compliance mounting mechanism.

A multi-chamber impeller pump includes an impeller, circumferentially spaced cams defining an impeller chamber, and circumferentially spaced evacuation ports. Each cam includes an engagement edge, an arcuate cam surface sloping radially inward, and a lobe. Each evacuation port is proximal to an intersection of a respective arcuate cam surface and lobe. As the impeller rotates, a corresponding end of a leading blade contacts a respective engagement edge and then a corresponding end of a trailing blade contacts the respective engagement edge thereby forming a unit chamber between leading and trailing blades. As the impeller continues to rotate, the end of the leading blade contacts a respective lobe and displaces the leading blade to decrease the volume of the unit chamber and expel fluid from the unit chamber through a respective evacuation port. A method of using the multi-chamber impeller pump is also disclosed.

A mud motor stator or a pump comprising of a tubular outer portion; a number of lobes extending radially inwardly from the tubular outer portion, at least one of which comprises a skeletal structure and method for producing a mud motor stator or a pump comprising of placing material and bonding the material together in a pattern dictated by the design shape of the stator or pump.

A fluid moving apparatus includes an electric motor having a rotor and a stator and a fluid displacement member. The rotor rotates relative to the stator on a common axis to generate a rotational output. The rotational output is provided to the fluid displacement member to power the fluid displacement member to one of move linearly along and rotate about the common axis. The stator includes one or more coils configured to power rotation of the rotor. The one or more coils extend circumferentially around and can be coaxial on the common axis.