A compressor includes a shell, a compression mechanism, a driveshaft operable to drive the compression mechanism to compress a fluid, and a ring-shaped counterweight assembly positioned on the driveshaft. The counterweight assembly includes a counterweight fixed on the driveshaft and a cover attached to the driveshaft via a snap fit connection. The counterweight includes a coupling ring and a main weight having an arcuate shape, the coupling ring defining a bore receiving the driveshaft to fix the counterweight on the driveshaft. The counterweight and the cover cooperate to define the counterweight assembly, the cover extending circumferentially between two cover end surfaces each positioned adjacent one of two circumferential main weight end surfaces to define a disk-shape of the counterweight assembly. The cover includes a coupling collar including a circular base and flexible fingers engageable with a circumferential groove defined on the driveshaft to form the snap fit connection.

An exhaust gas recirculation pump for an internal combustion engine that includes an electric motor assembly having an electric motor disposed within an electric motor housing. A roots device is coupled to the electric motor. The roots device includes a housing defining an internal volume. Rotors are disposed in the internal volume and connected to the electric motor. A bearing plate is attached to the housing wherein the bearing plate and an outer cover attached to the bearing plate defines an oil cavity. A transmission assembly is positioned on an opposing side of the housing relative to the electric motor and in the oil cavity.

A compressor which includes a male rotor assembly including an elongate male helical-shaped rotor having an axial cylindrical cavity therethrough, a stationary shaft axially aligned with the male rotor and through the cavity, a housing for housing the male rotor and its associated stationary shaft therein, wherein the shaft is fixed within the housing, and bearing means mounted within the cavity of the male rotor for bearing the friction between the rotor and the shaft as the male rotor rotates about the stationary shaft.

A scroll compressor, including a casing that forms an outer appearance thereof and having an oil storage space; an electromotive part installed inside of the casing to generate a drive force; a rotational shaft rotatably installed in the electromotive part; a compression part having an orbiting scroll installed to be capable of orbital rotation around the rotational shaft and a fixed scroll coupled to and engaged with the orbiting scroll to form a compression chamber between the orbiting scroll and the fixed scroll; and a bushing disposed between the fixed scroll and the rotational shaft and coupled to an outer circumference of the rotational shaft so as to rotate with the rotational shaft. The bushing is supported by one surface provided inside of the fixed scroll.

A compressor includes a shell and a main bearing housing positioned within the shell. The main bearing housing includes a scroll assembly positioned within the shell and positioned relative to a first cavity of the main bearing housing, the scroll assembly includes a non-orbiting scroll, an orbiting scroll, and a cylindrical hub, and a coupling positioned between the orbiting scroll and a fixed component and movable relative to at least one of the orbiting scroll and the fixed component. A first seal may be positioned between the orbiting scroll and the coupling, a second seal may be positioned between the coupling and the main bearing housing, and a third seal may be positioned between the cylindrical hub and the main bearing housing, wherein the main bearing housing and the orbiting scroll define a pressure cavity.

There is provided a restriction component with good slidability. A restriction component is provided on a back surface of a movable scroll that slides relative to a fixed scroll while rotating eccentrically, and restricts a rotation of the movable scroll while allowing the eccentric rotation of the movable scroll, and the restriction component is provided with a dynamic pressure generation groove configured for generating a dynamic pressure on the back surface of the movable scroll.