A vehicular wheel hub unit includes a radially outer bearing ring, a radially inner bearing ring, and a plurality of rolling elements supporting the inner bearing ring and the outer bearing ring for relative rotation. The inner bearing ring has an axially facing metal coupling surface configured to frictionally engage a connecting surface of an element, such as a bell of a constant velocity joint, adjacent to the inner bearing ring, and the coupling surface includes at least one first region having a plurality of coupling surface ablations configured to affect an amount of friction between the coupling surface and the connecting surface. Also a method including ablating at least a first region of a coupling surface of an inner bearing ring.

A motor shaft, a motor, and an electric vehicle. The motor shaft includes a shaft body and an insulation coating. The shaft body includes a first mounting portion and a second mounting portion that are connected by fastening. A positioning step surface is disposed at an end that is of the first mounting portion and that is close to the second mounting portion. The first mounting portion is configured to mount a rotor. The second mounting portion is covered with the insulation coating, and the second mounting portion is configured to mount a bearing. A resistivity of the insulation coating is not less than 10.sup.7 .Math.m. In this way, a possibility that a shaft current is generated when a shaft voltage discharges and breaks down a lubricating oil film in the bearing to form a path can be effectively reduced.

A steering shaft includes an inner shaft including first tooth parts, an outer shaft including second tooth parts, and a resin layer. The resin layer includes a plurality of thick film parts and at least four thin film parts. Each thick film part is disposed with a gap from one of the second tooth parts, and each thin film part contacts both one of the first tooth parts and one of the second tooth parts. At a section orthogonal to a central axis of the inner shaft, the thickness of each thin film part is smaller than the thickness of each thick film part.

A rolling bearing includes a first raceway ring having a first raceway surface, a second raceway ring having a second raceway surface, and a plurality of rolling elements held between the first raceway surface and the second raceway surface in a freely rollable manner. An oxide film containing Fe.sub.3O.sub.4 is provided on at least one of surfaces of the first raceway surface and the second raceway surface and surfaces of the rolling elements. A film thickness of the oxide film is 0.6 m or more and 2.0 m or less. A crystallite size calculated from a peak attributable to the (311) plane of the Fe.sub.3O.sub.4 is 2.5 nm or more and 3.2 nm or less.

Provided is a wheel bearing device that can further reduce weight while increasing rigidity. A wheel bearing device 1 comprises: an outer ring 2 having a double row of outer raceway surfaces 23, 24; an inner member (hub ring 3 and inner ring 4) having a double row of inner raceway surfaces 33, 41 opposing the double row of outer raceway surfaces 23, 24; and double ball rows 5, 6 accommodated between both raceway surfaces of the inner member and the outer ring 2 in a manner allowing rolling. The pitch diameter b of balls 7 in the ball rows 5, 6, and the pitch a between an outer side ball 7 and an inner side ball 7 in the ball rows 5, 6 satisfy the relationship b/a2.0.

Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

Metal-based ceramic composite coatings and related devices, assemblies, and methods include monocrystalline superhard particles dispersed in a metal matrix disposed on at least one wear surface of a component of an oil and gas well assembly, system, or device.

A rolling bearing, in particular of a wheel hub bearing unit for vehicles, and an associated method for reducing the friction between the rolling bodies of the bearing and respective raceways for the rolling bodies formed on the inner and outer rings of the rolling bearing. The rolling bodies and the raceways have a surface topography of a predetermined thickness, the rolling bodies and/or the raceways are coated with a layer of black oxide, and a lubricating fluid with predetermined physical/chemical characteristics is inserted between the inner and outer rings and in contact with the rolling bodies and with the raceways.

A rolling bearing including an inner ring, an outer ring, and a plurality of rolling elements disposed at a predetermined distance from each other along a circumference of a pitch circle, wherein a relational expression of log.sub.10t=A.Math.log.sub.10+C holds, where p denotes the predetermined distance, d denotes a diameter of each of the rolling elements, and t denotes a thickness between an outer ring raceway surface and an outer circumferential surface of the outer ring, and relations of 0.4A0.6 and 2C0 are satisfied.

A rolling bearing includes an outer ring having an outer surface configured to be fitted into a first component, an inner ring having an inner surface configured to be fitted onto a second component, at least one rolling element arranged between the outer ring and the inner ring, and an antimony-free composite coating on the outer surface of the outer ring and/or the inner surface of the inner ring. The antimony-free composite comprises a binder and polytetrafluorethylene as a solid lubricant.