A bearing device includes a rotational shaft; a first outer ring; a second outer ring; first balls; second balls disposed; and a C-spacer and a second spacer. α>δd is satisfied, where δd represents a difference between an inside diameter of the second spacer at an end portion on a second side and an outside diameter of a shaft outer circumferential face, and α represents a half of a difference between a diameter of a cylindrical face of the C-spacer on an outer circumferential side and a diameter of the cylindrical face of the C-spacer on an inner circumferential side.

A bearing device includes: at least one bearing that has a rolling element and a raceway surface to support a main shaft; a member disposed on a path through which pressing force generating a preload between the rolling element and the raceway surface is transmitted; and at least one load sensor element fixed to the member to measure the pressing force. At least one load sensor element is a chip component including a thin film pattern of which resistance changes according to the pressing force and a protective layer that insulates and protects thin film pattern.

A bearing device includes: at least one bearing that has a rolling element and a raceway surface to support a main shaft; a member disposed on a path through which pressing force generating a preload between the rolling element and the raceway surface is transmitted; and at least one load sensor element fixed to the member to measure the pressing force. At least one load sensor element is a chip component including a thin film pattern of which resistance changes according to the pressing force and a protective layer that insulates and protects thin film pattern.

The application is a motor capable of reducing vibration. A motor includes a shaft, a pair of bearings, a sleeve accommodating the pair of bearings, a magnet fixed at one of the shaft and sleeve, a coil fixed at the other of the shaft or the sleeve and opposing the magnet, and an elastic member disposed between the pair of bearings and satisfying Expression 1. D is an outer diameter [m] of the elastic member, d is a wire diameter (p [m] of the elastic member, γ is a unit volume weight [kg/m.sup.3] of a material of the elastic member, S is a no-load rotation number [rotation/min] of the shaft, and g is gravitational acceleration.

[00001]$\begin{array}{cc}S<\frac{20d\sqrt{\frac{\mathrm{gG}}{2\gamma }}}{{\pi D}^2}& \left(1\right)\end{array}$

Provided is a power transmission device including a housing and a ball screw device including a nut housed in the housing. The device includes a screw shaft passing through the nut, and balls disposed between the nut and the screw shaft. The device also includes a first bearing and a second bearing that are disposed to be adjacent to each other in a center axis direction parallel with a center axis of the nut between the housing and the nut; and a preload applying member constituted of an elastic body and configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing respectively include outer rings that are fitted to the housing and separated from each other in the center axis direction, and the first bearing and the second bearing are disposed to be a face-to-face combination.

A bearing unit configured to support a first component for rotary movement with respect to a second component includes a first bearing having an inner ring and an outer ring and a second bearing having an inner ring and an outer ring and a separator axially disposed between and connecting the outer ring of the first bearing and the outer ring of the second bearing in an interference fit manner or in a friction fit manner to form a preassembled unit. The separator may be annular and have a plastic base body with axial openings in which metal spacers, cylindrical rods, for example, are mounted.

The bearing seat device includes a bearing seat, a bearing set, a driven module, and an adjusting member. The bearing seat has a mounting hole, an adjusting slot, and an inserting hole. The adjusting slot divides a section of the bearing seat that is adjacent to the inserting hole and the mounting hole into a first side compartment and a second side compartment. The inserting hole extends from the first side compartment to the second side compartment. The bearing set is mounted in the mounting hole. The driven module extends into the mounting hole, is supported by the bearing set, and is rotatable relative to the bearing seat. The adjusting member engages the mounting hole and is operable to adjust a width of the adjusting slot between the first and the second side compartments and a diameter of the mounting hole.

The bearing seat device includes a bearing seat, a bearing set, a driven module, and an adjusting member. The bearing seat has a mounting hole, an adjusting slot, and an inserting hole. The adjusting slot divides a section of the bearing seat that is adjacent to the inserting hole and the mounting hole into a first side compartment and a second side compartment. The inserting hole extends from the first side compartment to the second side compartment. The bearing set is mounted in the mounting hole. The driven module extends into the mounting hole, is supported by the bearing set, and is rotatable relative to the bearing seat. The adjusting member engages the mounting hole and is operable to adjust a width of the adjusting slot between the first and the second side compartments and a diameter of the mounting hole.

A bearing assembly for a turbocharger includes a turbine wheel-side ball bearing at a first axial end of a tubular body, a compressor impeller-side ball bearing at a second axial end of the tubular body, and a bearing housing. The bearing housing includes a first opposed wall opposed to an axially outer side of an outer race of the turbine wheel-side ball bearing, and a second opposed wall opposed to an axially outer side of an outer race of the compressor impeller-side ball bearing. The outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing have axially outer end surfaces which are axially outwardly displaced from respective axial end surfaces of the tubular body so that oil films are present between the respective outer races and the corresponding opposed walls.

A bearing assembly for a turbocharger includes a turbine wheel-side ball bearing at a first axial end of a tubular body, a compressor impeller-side ball bearing at a second axial end of the tubular body, and a bearing housing. The bearing housing includes a first opposed wall opposed to an axially outer side of an outer race of the turbine wheel-side ball bearing, and a second opposed wall opposed to an axially outer side of an outer race of the compressor impeller-side ball bearing. The outer race of the turbine wheel-side ball bearing and the outer race of the compressor impeller-side ball bearing have axially outer end surfaces which are axially outwardly displaced from respective axial end surfaces of the tubular body so that oil films are present between the respective outer races and the corresponding opposed walls.