A roller bearing includes an outer ring, an inner ring, and plural rolling elements rollably interposed between mutual raceway surfaces of the outer and inner rings, and is used by fitting an outer diameter surface of the outer ring serving as a fitting surface to a housing serving as a mating member or by fitting an inner diameter surface of the inner ring serving as a fitting surface to a shaft serving as the mating member. The fitting surface is provided with at least one protrusion so that a static torque T.sub.hold=Σ(F×r) generated by the protrusion is equal to or greater than a torque T.sub.creep generated by creep.

Embodiments of the present disclosure are directed to a roller-skate bearing seat truing tool comprising a plurality of spaced teeth, a first handle, and a second handle. The plurality of spaced teeth may be operable to true up a cylindrical surface of a roller-skate bearing seat and a vertical surface of the roller-skate bearing seat. The first handle may comprise a protrusion longitudinally extending from one end. The second handle may comprise a receptacle at one end configured to slidably receive the protrusion. The plurality of spaced teeth may be disposed about an upper rim of the receptacle, on an upper rim of the first handle, about the protrusion, or both.

Systems and methods of monitoring lubrication of a gear assembly during operation of a machine provide for receiving at a control system, a signal from a sensor indicative of a value obtained by the sensor for an electrical property of a circuit crossing the gear assembly operably coupled to the machine, ascertaining whether the value for the electrical property corresponds to a warning level for a condition of the lubricant film, and outputting a control command when the value for the electrical property corresponds to the warning level for the condition of the lubricant film.

Systems and methods of monitoring lubrication of a gear assembly during operation of a machine provide for receiving at a control system, a signal from a sensor indicative of a value obtained by the sensor for an electrical property of a circuit crossing the gear assembly operably coupled to the machine, ascertaining whether the value for the electrical property corresponds to a warning level for a condition of the lubricant film, and outputting a control command when the value for the electrical property corresponds to the warning level for the condition of the lubricant film.

One aspect of the disclosure relates to a sliding member. The sliding member includes: a first sliding portion having a first lubricant placed between first parts of a first friction sliding mechanism; a second sliding portion having a second lubricant placed between second parts of a second friction sliding mechanism; and a third sliding portion having a third lubricant placed between third parts of a third friction sliding mechanism. The first sliding portion is in contact with the third lubricant, and the second sliding portion is not in contact with the third lubricant. The second lubricant contains an additive containing conductive carbon, and the third lubricant contains no conductive carbon. The second lubricant contains a relatively larger amount of the conductive carbon than the first lubricant.

A gearbox including an angular contact ball bearing comprising a first row of balls provided with a plurality of balls, a second row of balls provided with another plurality of balls, at least one inner ring and at least one outer ring. According to the invention, in a degraded operating mode of the bearing, the first row of balls is configured to transmit at least one first axial force oriented along a first axis and at least one second axial force oriented along a second axis opposite the first axis, the second row of balls transmitting no axial force.

A bearing assembly of an electric drive assembly for a vehicle includes an insulating device having a sleeve with an electrically insulating coating, and a bearing device disposed in the sleeve. In an example embodiment, the sleeve has an inner peripheral surface and an outer peripheral surface, and the outer peripheral surface is formed by the electrically insulating coating. In an example embodiment, the sleeve is formed from steel, and the electrically insulating coating is formed from a plastic material having an electrically insulating property. In an example embodiment, the sleeve is designed as a cylinder having an end face with an outer side, and the electrically insulating coating is disposed on the outer side. In an example embodiment, the bearing device is a floating bearing axially movable relative to the sleeve.

A bearing assembly of an electric drive assembly for a vehicle includes an insulating device having a sleeve with an electrically insulating coating, and a bearing device disposed in the sleeve. In an example embodiment, the sleeve has an inner peripheral surface and an outer peripheral surface, and the outer peripheral surface is formed by the electrically insulating coating. In an example embodiment, the sleeve is formed from steel, and the electrically insulating coating is formed from a plastic material having an electrically insulating property. In an example embodiment, the sleeve is designed as a cylinder having an end face with an outer side, and the electrically insulating coating is disposed on the outer side. In an example embodiment, the bearing device is a floating bearing axially movable relative to the sleeve.

A state determination device for a hub unit bearing includes: a holding unit that holds reference information of magnetic characteristics at a predetermined position in the vicinity of a flange portion included in the hub unit bearing; an acquisition unit that acquires measurement information of the magnetic characteristics at the predetermined position of the hub unit bearing; a derivation unit that derives a change amount between the reference information held by the holding unit and the measurement information acquired by the acquisition unit; and a determination unit that determines a state of the hub unit bearing based on the change amount derived by the derivation unit. The predetermined position is a position at which the magnetic characteristics vary with a stress change with respect to the flange portion.

A state determination device for a hub unit bearing includes: a holding unit that holds reference information of magnetic characteristics at a predetermined position in the vicinity of a flange portion included in the hub unit bearing; an acquisition unit that acquires measurement information of the magnetic characteristics at the predetermined position of the hub unit bearing; a derivation unit that derives a change amount between the reference information held by the holding unit and the measurement information acquired by the acquisition unit; and a determination unit that determines a state of the hub unit bearing based on the change amount derived by the derivation unit. The predetermined position is a position at which the magnetic characteristics vary with a stress change with respect to the flange portion.