Abstract: A rolling bearing includes an inner ring, an outer ring, a plurality of balls, a cage that holds the balls, and a sealing device that is attached to each of opposite sides of the outer ring in an axial direction to prevent foreign matter from entering inside the bearing. A noise-reduction portion that attenuates sound inside the bearing is formed on at least one of a surface of the cage and a bearing inner-side surface of the sealing device.

Abstract: A ball bearing includes an inner ring having an outer periphery in which an inner raceway groove is formed, an outer ring having an inner periphery in which an outer raceway groove is formed, a plurality of balls interposed between the inner raceway groove and the outer raceway groove, and an annular cage that holds the balls. The cage includes an annular portion positioned on one side in an axial direction with respect to the balls and a plurality of cage bar portions that extends from the annular portion toward the other side in the axial direction. Each cage bar portion has a guide portion, and this guide portion positions the cage by coming into contact with the outer raceway groove at one location in a non-contact area other than an area in which the corresponding ball is in contact with the outer raceway groove.

Abstract: A ball bearing includes an inner ring having an outer periphery in which an inner raceway groove is formed, an outer ring having an inner periphery in which an outer raceway groove is formed, a plurality of balls interposed between the inner raceway groove and the outer raceway groove, and an annular cage that holds the balls. The cage includes an annular portion positioned on one side in an axial direction with respect to the balls and a plurality of cage bar portions that extend from the annular portion toward the other side in the axial direction. Each cage bar portion has a guide portion that positions the cage by coming into contact with the inner raceway groove in a non-contact area other than an area in which the corresponding ball is in contact with the inner raceway groove.

Abstract: An inner ring has a rib face as a concave surface that is formed on the larger diameter side of an inner ring and that contacts large end faces of tapered rollers. A tapered roller bearing satisfies Ri>R?Rr, where Rr represents a curvature radius of the large end face, Ri represents a curvature radius of the rib face 8 in a longitudinal section of the inner ring 2, R represents a distance from a cone center to a reference point. The distance R is the distance from the cone center to the reference point, where the reference point is the intersection of the rib face and an imaginary line extending from the cone center and along an inner ring raceway surface in the longitudinal section of the inner ring 2. Surface roughness of the rib face is greater than that of the large end face.

Abstract: A rolling bearing unit includes: a rolling bearing including an inner ring, an outer ring and a plurality of rolling elements disposed between the inner ring and the outer ring; an annular outer ring spacer disposed adjacent to one axial end of the rolling bearing, the outer ring spacer having a grease reservoir in the form of a groove extending along the circumferential direction of the outer ring spacer, and an opening that provides communication between the grease reservoir and the inside of the rolling bearing; and grease retained in the grease reservoir. Channels are formed in the grease to extend from the opening along the axial direction of the outer ring spacer.

Abstract: A rolling bearing device includes a rolling bearing; and a spacer provided adjacent to one side of the rolling bearing in an axial direction and having a grease reservoir and a flow path, the grease reservoir being in a form of a groove, extending along a circumferential direction, and having grease reserved in the grease reservoir, and the flow path providing communication between the grease reservoir and an inner part of the rolling bearing. The spacer includes an annular wall surface that defines an inner periphery of the grease reservoir. An end of the annular wall surface on a side of the rolling bearing in the axial direction of the grease reservoir is continuous with an opposed end face of the spacer that is opposed to the rolling bearing. An entire area of the annular wall surface is constituted by a flat surface.

Abstract: A rolling bearing unit includes: a rolling bearing including an inner ring, an outer ring and a plurality of rolling elements disposed between the inner ring and the outer ring; an annular outer ring spacer disposed adjacent to one axial end of the rolling bearing, the outer ring spacer having a grease reservoir in the form of a groove extending along the circumferential direction of the outer ring spacer, and an opening that provides communication between the grease reservoir and the inside of the rolling bearing; and grease retained in the grease reservoir. Channels are formed in the grease to extend from the opening along the axial direction of the outer ring spacer.

Abstract: A command rotation speed is set to an initial rotation speed, and a forced commutation mode is started. In the forced commutation mode, a rotation speed is increased by a predetermined increase amount each time and forced commutation is executed until the rotation speed reaches a set rotation speed. Then, a switchover to the sensorless control mode is made when the rotation speed reaches the set rotation speed (S4) and a rotor position becomes detectable.

Abstract: A command rotation speed is set to an initial rotation speed, and a forced commutation mode is started. In the forced commutation mode, a rotation speed is increased by a predetermined increase amount each time and forced commutation is executed until the rotation speed reaches a set rotation speed. Then, a switchover to the sensorless control mode is made when the rotation speed reaches the set rotation speed (S4) and a rotor position becomes detectable.