A supercharger constructed in accordance to one example of the present disclosure includes a housing, first and second rotors, a bearing plate and a pair of sleeves. The first and second rotors are received in cylindrical overlapping chambers of the housing, the first rotor supported by a first rotor shaft, the second rotor supported by a second rotor shaft. The bearing plate is coupled to the housing and has an oil cavity side and an air cavity side. The bearing plate is formed of aluminum. The pair of sleeves can be received by the bearing plate and support respective bearings rotatably supporting respective first and second axle shafts. The pair of sleeves are formed of steel.

Invention provides gear pump bearing block and method of manufacturing gear pump bearing block. Bearing block includes a bush formed of antifriction alloy, bush having cylindrical portion providing bore adapted to receive bearing shaft of gear of pump, and further having flange portion extending radially outwardly at end of cylindrical portion to provide thrust face adapted to slidingly engage with side surface of gear. Bearing block also has backing layer covering radially outer surface of cylindrical portion and rear face of flange portion, backing layer being formed of less dense alloy compared to antifriction alloy. Furthermore, there is an annular gallery embedded in flange portion such that gallery is spaced from surface of bore and from thrust face, gallery surrounding bore, with inlet to and outlet from annular gallery such that, in use, fluid flows from inlet, through annular gallery to provide cooling of thrust face, and then to outlet.

The invention provides a gear pump bearing block and method of manufacturing gear pump bearing block. Bearing block includes bush formed of antifriction alloy, having a cylindrical portion providing bore adapted to receive bearing shaft of a gear of pump, and further having a flange portion extending radially outwardly at end of cylindrical portion to provide thrust face adapted to slidingly engage with side surface of gear. Bearing block also has backing layer covering radially outer surface of cylindrical portion and rear face of flange portion, backing layer being formed of relatively less dense alloy compared to antifriction alloy. Furthermore, there is an annular formation of one or more stiffening members, formation surrounding bore, the, or each, stiffening member being embedded in flange portion, and the, or each, stiffening member being formed of material having higher elastic modulus than antifriction alloy.

It is intended to provide a vacuum pump so that without upsizing the vacuum pump, noise and vibration are reduced, heat dissipation property is secured, and the casing is downsized. Therefore, at least one turning part is provided in an exhausting path formed in a casing body. The casing body is formed of a material whose thermal conductivity is higher than that of a rotor and vanes, and a cylinder part where the vanes slide is press fitted in the casing body.

It is intended to provide a vacuum pump so that without upsizing the vacuum pump, noise and vibration are reduced, heat dissipation property is secured, and the casing is downsized. Therefore, at least one turning part is provided in an exhausting path formed in a casing body. The casing body is formed of a material whose thermal conductivity is higher than that of a rotor and vanes, and a cylinder part where the vanes slide is press fitted in the casing body.