Disclosed is a bearing assembly for an electric motor for a vehicle, providing at least one main bearing configured to support a rotational element of the electric motor, and a sacrificial bearing. The main bearing includes at least one inner ring, at least one outer ring and at least one plurality of rolling elements. The sacrificial bearing provides an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring. A value of a breakdown voltage for the sacrificial bearing is less than a value of the breakdown voltage for the at least one main bearing.

A bearing retainer for use in a bearing is provided. The bearing includes an inner ring, rolling elements and an outer ring. The bearing retainer has a body. The body defines an inner periphery and an outer periphery of the body. The body further defines a plurality of openings extending from the inner periphery to the outer periphery of the body. The plurality of openings are adapted to retain the rolling elements in a spaced apart relationship. The body further defines opposed faces extending from the inner periphery to the outer periphery of the body. The body further defines a plurality of face pockets formed in at least one of the faces of the body. The face pockets are adapted to storing lubrication. The body further includes a pathway from at least one face pocket of the body to the inner periphery of the body.

A bearing retainer for use in a bearing is provided. The bearing includes an inner ring, rolling elements and an outer ring. The bearing retainer includes a body. The body defines an inner periphery and an outer periphery of the body. The body further defines a plurality of inner walls. Each inner wall defines an opening extending from the inner periphery to the outer periphery of the body. The plurality of openings are adapted to receive one of the rolling elements. The inner walls are adapted to keep the rolling elements in a spaced apart relationship. At least one of the inner walls defines a aperture through the body. The aperture is adapted for storing lubrication therein.

The invention has an object of providing grease reduced in an amount of the flying grease and an amount of the outgas, and superior in low-temperature characteristic, an antifriction bearing using the grease, an antifriction bearing device, and an information recording/reproducing device. A grease includes a base oil, and a thickener, the base oil includes mineral oil and poly-α-olefin, the poly-α-olefin is higher in mass than the mineral oil, the poly-α-olefin includes poly-α-olefin higher in kinetic viscosity than the mineral oil, the kinetic viscosity of the base oil at 40° C. is in a range of 40 through 90 mm.sup.2/s, and worked penetration is in a range of 200 through 250. Further, an antifriction bearing, an antifriction bearing device, and an information recording/reproducing device use the grease.

A rolling bearing having an inner ring, an outer ring and a plurality of rolling elements being arranged between the inner ring and the outer ring is provided. The inner ring and the outer ring each include a raceway for the plurality of rolling elements. Each raceway encompasses the plurality of rolling elements symmetrically. The rolling bearing further includes an asymmetric cage being arranged between the inner ring and the outer ring for holding the rolling elements. The rolling bearing is lubricated by a lubricant being arranged on each axial side of the plurality of rolling elements. The raceways are offset in the same axial direction from the axial center of the inner ring and the outer ring such that the shear rate acting on the lubricant is equal on each axial side of the rolling bearing.

A power transmission device including a housing and a ball screw device including a nut, a screw shaft, and a plurality of balls. The device includes a pulley device including a driving pulley configured to be driven by receiving power transmitted from a power source, a driven pulley fixed to the nut, and a belt wound around outer peripheral surfaces of the driving pulley and the driven pulley. The device also includes a first bearing and a second bearing disposed between the housing and the nut in a center axis direction parallel with a center axis of the nut; and a preload applying member configured to apply preloads to the first bearing and the second bearing. The first bearing and the second bearing are respectively disposed on both sides of the driven pulley to be a face-to-face combination, and each of the first bearing and the second bearing includes an outer ring engaged with the housing.

A rolling bearing unit provided with a radially outer ring having an assembly groove, two radially inner rings, two series of rolling elements interposed between the radially outer ring and the radially inner rings and defining between them a first internal grease reservoir. The groove is arranged in an axially intermediate position with respect to the two radially inner rings and a grease dispensing device is housed inside the groove of the radially outer ring and is in turn provided with a second grease reservoir formed inside the radially outer ring and communicating with the first reservoir via the groove. A permeable retaining wall housed is inside the groove so as to retain the grease inside the second reservoir and allow it to flow out towards the first reservoir during operation of the bearing unit, dispensing it in a controlled manner.

A rolling bearing capable of achieving reduction in torque is provided. The rolling bearing includes an inner ring and an outer ring disposed coaxially with each other, a rolling element disposed between the inner ring and the outer ring, a seal member configured to cover an area between the inner ring and the outer ring from an outside in an axial direction, and filled grease disposed between the rolling element and the seal member. The filled grease includes a first ring-like part which extends to form a circumferential shape centering on a common axis of the inner ring and the outer ring, and which has contact with one of the inner ring and the outer ring, and a second ring-like part which extends to form a circumferential shape centering on the common axis, which is connected to the first ring-like part at an outer side in the axial direction, and which has contact with the seal member.

Disclosed is a bearing race comprising a surface having a plurality of pores formed therein. A lubricant is provided in the pores. The race has a body having a porous volume contiguous with the surface. The surface includes a load bearing zone configured to be in contact with a rolling element of a bearing, the pores being distributed on the surface to provide the lubricant to the load bearing zone.

Provided is a rolling bearing that can both ensure durability and reduce rotational resistance. The rolling bearing includes a seal member that is mounted on an outer ring and that covers a space between an inner ring and the outer ring from an outer side in an axial direction, and grease disposed between a rolling element and the seal member. The seal member includes an annular pedestal portion in contact with the outer ring from an outer side in the axial direction, an extending portion that extends outward in the axial direction from an inner peripheral edge of the pedestal portion, and a flat surface portion that extends along a radial direction from an end edge of the extending portion on an outer side in the axial direction toward the inner ring. The grease includes an outer ring contact portion in contact with an inner peripheral surface of the outer ring, and a seal member contact portion in contact with the flat surface portion on an outer side in the axial direction and an inner ring side with respect to the outer ring contact portion. An area of the seal member contact portion is larger than a contact area between the grease and the extending portion as well as the pedestal portion of the seal member.