A rolling bearing having an annular inner ring and an annular outer ring in relative rotation around a central axis and rolling elements housed between raceways provided in the two rings. At least one of the rings includes two concentric annular ring parts made of metallic material, and an annular layer made of electrically insulating material, the layer being accommodated between the two parts.

A bearing system for a rotating vertical shaft includes a first ball bearing, having a first pitch diameter and a first axial stiffness and a second ball bearing having a second pitch diameter and a second axial stiffness. The first ball bearing is a deep groove Conrad bearing. The second ball bearing is an angular contact bearing. The first and second ball bearings are coaxial, secured to one another and rotatable together. The first pitch diameter is at least 1.5 times greater than the second pitch diameter. The bearing system has an axial stiffness ratio defined by the first axial stiffness divided by the second axial stiffness. The axial stiffness ratio is based on an axial preload force applied to the second outer ring such that an operating torque of the bearing system is within a predetermined range at temperatures from minus 40 to positive 85 degrees Celsius.

A bearing assembly includes an inner ring and an outer ring that define a bearing interior between them and either the inner ring or the outer ring is fixed. When the inner ring is fixed, the inner ring includes at least one substantially radial through opening and when the outer ring is fixed, the outer ring includes at least one substantially axial and/or radial through opening, or at least one substantially axial and/or radial through opening is provided on a ring fixedly connected to the outer ring. The through opening is disposed between a 9 o'clock position and a 3 o'clock position on the inner ring when the inner ring is fixed or on the outer ring when the outer ring is fixed.

A high-speed ball bearing includes an outer ring, an inner ring, a plurality of balls, and a ball retainer. The ball retainer includes a plurality of pocket holes for arranging a plurality of balls, an inner circumferential surface of each of the pocket holes have a spherical surface is coaxial to the ball. A gap between an outer circumferential surface of the ball retainer and an inner circumferential surface of the ring is defined as a first gap, and a gap between the pocket hole and the corresponding ball is defined as a second gap. The first gap and the second gap have the following relationship: W2=(W1r)A.

Greasable idler pulleys and related kits and methods are disclosed. The greasable idler pulley has a rotating body, a bearing, to enable the rotating body to rotate with respect to a shaft, and grease fitting defined through the rotating body. The rotating body may have a bearing seal cap having an orifice and a rotator. The grease fitting may be in fluid communication with the bearing through the orifice in the bearing seal cap. Kits are also contemplated, such as a kit for retrofitting a non-regreasable idler pulley including a rotator to a regreasable idler pulley. Methods may include methods of producing a regreasable idler pulley from a non-regreasable idler pulley.

A packaged bearing unit is disclosed including an outer surface for receiving an aircraft landing gear wheel and an inner surface for receiving an axle. The unit may include first and second spaced-apart sets of tapered roller bearings, held between inner and outer raceways. There may be a bearing setting spacer which can be used when setting and pre-loading the bearings. The bearing unit may be a sealed unit which includes a pre-set amount of lubricant (grease) for lubricating the bearings. One or more sensors may be retained in a void between the sets of bearings.

A high-speed ball bearing includes an outer ring, an inner ring, a plurality of balls, and a ball retainer. The ball retainer includes a plurality of pocket holes for arranging a plurality of balls, an inner circumferential surface of each of the pocket holes have a spherical surface is coaxial to the ball. A gap between an outer circumferential surface of the ball retainer and an inner circumferential surface of the ring is defined as a first gap, and a gap between the pocket hole and the corresponding ball is defined as a second gap. The first gap and the second gap have the following relationship: W2=(W1r)A.

According to an aspect of the present disclosure, a seal structure includes a rotary shaft that is provided inside a housing, a metal-made surrounding portion of the housing that surrounds the rotary shaft in a radial direction of the rotary shaft, and a resin-made seal member that faces an inner circumferential surface of the surrounding portion and rotates together with the rotary shaft.

A pivot assembly bearing device includes a shaft having an outer peripheral surface and a rolling bearing fixed to the shaft. An annular sealing surface axially overlapping with at least a part of an end surface of the rolling bearing is provided on an axially outer side of the rolling bearing. An oil-repellent film is annularly formed on at least one of the sealing surface and a part of the outer peripheral surface of the shaft located axially outward from the rolling bearing.

A cover comprises a substrate and a grease lid. The substrate comprises a main body comprising a branched grease pathway, a locating side comprising a grease supply port, and a lubricating side comprising a plurality of grease ports. The grease lid constrains the branched grease pathway and is configured so that when grease enters the locating side grease supply port, the grease traverses the branched grease pathway and exits the grease ports.