A main shaft device is attached to a work machine. The main shaft device is provided with a main shaft that supports a tool or a workpiece, and a main shaft motor that causes the main shaft to rotate. The main shaft device is provided with bearings that are rolling bearings which support the main shaft in an inner race, and a housing and a rear housing that secure an outer race of the bearings. The housing and the rear housing are formed of a material having a coefficient of thermal expansion greater than that of the main shaft.

A rolling bearing device includes a rotary shaft; a housing; a pair of rolling bearings; an outer ring spacer; an elastic member provided in a bottom side of the housing, the bottom side of the housing being a second axial side of the housing, and the elastic member being configured to urge the rolling bearings, the outer ring spacer, and the rotary shaft toward a first axial side; and a retaining ring that is fitted into a circumferential groove provided on an inner periphery in the first axial side of the housing, the retaining ring being in axial contact with the outer ring of the rolling bearing located on the first axial side, and the retaining ring including at least three arc members arranged in a circumferential direction.

A shaft assembly may include two or more Poka-Yoke bearing caps, each Poka-Yoke bearing cap having a pair of reference bores offset from a central axis of the bearing cap by differing offset distances, and each bearing cap defining a semi-circular recess that is positioned so as to align in use a central axis of the semi-cylindrical recess in the bearing cap with an axis of rotation of a shaft rotatably supported by the bearing cap. The differing offsets of the reference bores prevent the bearing cap from being assembled in a reversed orientation. To ensure that each bearing cap can only be fitted in one position, a centre spacing between the first and second reference bores of each bearing cap is different to the centre spacing used for other bearing caps used to support a single shaft.

A shaft assembly may include two or more Poka-Yoke bearing caps, each Poka-Yoke bearing cap having a pair of reference bores offset from a central axis of the bearing cap by differing offset distances, and each bearing cap defining a semi-circular recess that is positioned so as to align in use a central axis of the semi-cylindrical recess in the bearing cap with an axis of rotation of a shaft rotatably supported by the bearing cap. The differing offsets of the reference bores prevent the bearing cap from being assembled in a reversed orientation. To ensure that each bearing cap can only be fitted in one position, a centre spacing between the first and second reference bores of each bearing cap is different to the centre spacing used for other bearing caps used to support a single shaft.

A main shaft device is attached to a work machine. The main shaft device is provided with a main shaft that supports a tool or a workpiece, and a main shaft motor that causes the main shaft to rotate. The main shaft device is provided with bearings that are rolling bearings which support the main shaft in an inner race, and a housing and a rear housing that secure an outer race of the bearings. The housing and the rear housing are formed of a material having a coefficient of thermal expansion greater than that of the main shaft.

A dustproof bearing assembly includes a base having a shaft tube. The shaft tube has an open end with an opening. At least one bearing is coupled to an inner periphery of the shaft tube. A rotating member includes a shaft seat. A shaft includes a first end coupled to the shaft seat and a second end extending through a shaft-receiving hole of the at least one bearing. A dustproof member includes a lower face and an upper face. The lower face is spaced from the open end of the shaft tube. The dustproof member covers the opening. The upper face of the dustproof member abuts a bottom of the shaft seat. The dustproof member has an outer diameter larger than an inner diameter of the shaft tube. The dustproof bearing assembly can be used in a motor.

A dustproof bearing assembly includes a base having a shaft tube. The shaft tube has an open end with an opening. At least one bearing is coupled to an inner periphery of the shaft tube. A rotating member includes a shaft seat. A shaft includes a first end coupled to the shaft seat and a second end extending through a shaft-receiving hole of the at least one bearing. A dustproof member includes a lower face and an upper face. The lower face is spaced from the open end of the shaft tube. The dustproof member covers the opening. The upper face of the dustproof member abuts a bottom of the shaft seat. The dustproof member has an outer diameter larger than an inner diameter of the shaft tube. The dustproof bearing assembly can be used in a motor.

An electric actuator includes: a motor; a first case accommodating the motor; a second case located on one side in an axial direction of the first case; a bearing holder fixed to the first case; and a first bearing held by the bearing holder. The first case has a wall part covering the other side in the axial direction of a stator and having a through hole. The bearing holder has: a holder cylindrical part holding the first bearing and inserted into the through hole; and a holder flange part fixed to the wall part. An inner diameter of the through hole is larger than an outer diameter of the holder cylindrical part. At least a part of a radially outer surface of the holder cylindrical part in a circumferential direction is located in a position radially inside and away from a radially inner surface of the through hole.

A linear transmission device suitable for mounting of at least one electronic component includes: an elongated shaft member; a movable member sleeved onto the elongated shaft member and having an end surface; a housing unit disposed on the end surface and includes: a base member, at least one accommodating member and a housing member. The base member is disposed on the elongated shaft member, and includes: an assembling surface and a plurality of assembling portions. The accommodating member is disposed on the base member and includes: a first engaging surface, a second engaging surface, and an accommodating groove for accommodating the electronic component. The first engaging surface has plural connecting portions for combining with the assembling portions. The second engaging surface has plural engaging grooves, the housing member is sleeved on the accommodating member, and includes a plurality of engaging protrusions for engaging with the plurality of engaging grooves.

A fluid pump for a motor vehicle includes a pump wheel which is co-rotatably connected with a driving device via a rotor shaft, and a shaft bearing system for the rotor shaft. The shaft bearing system includes a bearing receptacle having a support flange, and a first and a second ball bearing. The first and the second ball bearing are each fixed to a radial outside of the rotor shaft, are each axially shiftable within the static bearing receptacle, and are positioned at opposite axial sides of the support flange. An outer race of the first ball bearing contacts the support flange. An outer race of the second ball bearing is axially preloaded away from the support flange via a preload spring. The first and the second ball bearing are each radially supported within the static bearing receptacle only by an elastic support ring which radially surrounds the outer races.