A twin-shaft pump comprising: a pumping chamber; two rotatable shafts each mounted on bearings is disclosed. Each of the two rotatable shafts comprises at least one rotor element, the rotor elements being within the pumping chamber and the two rotatable shafts extending beyond the pumping chamber to a support member. The support member comprises mounting means for mounting the bearings at a predetermined distance from each other, the predetermined distance defining a distance between the two shafts. A thermal break between the pumping chamber and the support member is provided for impeding thermal conductivity between the pumping chamber and the support member, such that the pumping chamber and support member can be maintained at different temperatures. The support member and the rotor elements are formed of different materials, a coefficient of thermal expansion of a material forming the support member being higher than a coefficient of thermal expansion of a material forming the rotor elements.

A hydraulic gerotor pump for an automatic transmission may comprise a housing and a gear set rotatably disposed within the housing. The gear set may comprise an inner gear and an outer gear having radially opposed intermeshing teeth that together define a plurality of circumferentially disposed variable volume pumping chambers therebetween. The housing may be made of a first aluminum-based material, and the inner gear and the outer gear of the gear set may be made of a second aluminum-based material. The linear coefficient of thermal expansion of the first aluminum-based material may be substantially the same as that of the second aluminum-based material.

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.

A hydraulic gerotor pump for an automatic transmission may comprise a housing and a gear set rotatably disposed within the housing. The gear set may comprise an inner gear and an outer gear having radially opposed intermeshing teeth that together define a plurality of circumferentially disposed variable volume pumping chambers therebetween. The housing may be made of a first aluminum-based material, and the inner gear and the outer gear of the gear set may be made of a second aluminum-based material. The linear coefficient of thermal expansion of the first aluminum-based material may be substantially the same as that of the second aluminum-based material.

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): I(b/a)k and Formula (2): I(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 I 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.

A twin-shaft pump comprising: a pumping chamber; two rotatable shafts each mounted on bearings is disclosed. Each of the two rotatable shafts comprises at least one rotor element, the rotor elements being within the pumping chamber and the two rotatable shafts extending beyond the pumping chamber to a support member. The support member comprises mounting means for mounting the bearings at a predetermined distance from each other, the predetermined distance defining a distance between the two shafts. A thermal break between the pumping chamber and the support member is provided for impeding thermal conductivity between the pumping chamber and the support member, such that the pumping chamber and support member can be maintained at different temperatures. The support member and the rotor elements are formed of different materials, a coefficient of thermal expansion of a material forming the support member being higher than a coefficient of thermal expansion of a material forming the rotor elements.

An electric compressor includes a first scroll and a second scroll engaged with the first scroll and making an orbiting motion to form a pair of two compression chambers with the first scroll. A rotary shaft is eccentrically coupled to the second scroll and is rotatably supported by a bearing member. A frame is fixed to an opposite side of the first scroll from the second scroll with the second scroll being interposed between the frame and the first scroll. The frame includes a bearing support portion, and the bearing member is inserted into and fixed to the bearing support member with an interference fit.

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.