A deep groove ball bearing having an inner ring, an outer ring and a plurality of rolling elements set between the inner and outer rings. The rolling elements have a diameter D.sub.w ≤ 0.5H.sub.1 , up to D.sub.w ≤ 0.35H.sub.1 . H.sub.1 is the radial dimension of the bearing in the sense of thickness and is numerically equal to half of the difference between the outer diameter and inner diameter of the bearing. By using sufficient number but smaller size of rolling elements, the deep groove ball bearing can obtain enhanced axial and radial rigidity, which is not only conducive to reducing creep and wear of bearing mating surfaces, avoiding early failure of bearings, but also improving the rotational accuracy of equipment, avoiding vibration, noise and other problems caused by insufficient bearing rigidity, fully meeting the comprehensive needs of rotating equipment for bearing performance.

A deep groove ball bearing having an inner ring, an outer ring and a plurality of rolling elements set between the inner and outer rings. The rolling elements have a diameter D.sub.w ≤ 0.5H.sub.1 , up to D.sub.w ≤ 0.35H.sub.1 . H.sub.1 is the radial dimension of the bearing in the sense of thickness and is numerically equal to half of the difference between the outer diameter and inner diameter of the bearing. By using sufficient number but smaller size of rolling elements, the deep groove ball bearing can obtain enhanced axial and radial rigidity, which is not only conducive to reducing creep and wear of bearing mating surfaces, avoiding early failure of bearings, but also improving the rotational accuracy of equipment, avoiding vibration, noise and other problems caused by insufficient bearing rigidity, fully meeting the comprehensive needs of rotating equipment for bearing performance.

A method of providing electrical insulation for at least one portion of a bearing element is disclosed herein. The method includes electrostatically spraying a polymer coating to the at least one portion of the bearing element, and the polymer coating comprises a thermoset epoxy coating or a self-adhering nylon powder coating. The bearing element can be grounded during the electrostatic spraying. The method includes heating the polymer coating in an oven at a temperature less than or equal to 220° C. for a predetermined time, such that after removal from the oven, the polymer coating has a porosity of less than 10%. The coated bearing element has a resistance of at least 50 MΩ resistance under dry conditions and 10 MΩ resistance under wet conditions.

A method of providing electrical insulation for at least one portion of a bearing element is disclosed herein. The method includes electrostatically spraying a polymer coating to the at least one portion of the bearing element, and the polymer coating comprises a thermoset epoxy coating or a self-adhering nylon powder coating. The bearing element can be grounded during the electrostatic spraying. The method includes heating the polymer coating in an oven at a temperature less than or equal to 220° C. for a predetermined time, such that after removal from the oven, the polymer coating has a porosity of less than 10%. The coated bearing element has a resistance of at least 50 MΩ resistance under dry conditions and 10 MΩ resistance under wet conditions.

A bearing ring has first and second cylindrical surfaces, first and second annular side surfaces and at least one compensation element attached to the bearing ring, preferably in a groove at a junction of the first cylindrical surface and the first annular side surface. The bearing ring is manufactured from a first material having a first coefficient of thermal expansion and is configured to be connected to a component that is manufactured from a second material having a second coefficient of thermal expansion, and the at least one compensation element is manufactured from a third material having a coefficient of thermal expansion that is greater than or equal to the coefficient of thermal expansion of the second material. Also a bearing assembly including the bearing ring and the component.

An insulating device for a bearing mountable within a housing, the bearing having an inner ring and an outer ring with an outer circumferential surface and opposing axial ends and a plurality of rolling elements disposed there between. The insulating device comprises: a first annular part, which is adapted to be in contact to the outer circumferential surface of the outer ring, and a second annular part, which is also adapted to be in contact to the outer circumferential surface of the outer ring. The first and second part form the insulation device which is adapted to contact, in an assembled state of the bearing in the housing, both the outer ring and the housing. The first part is thermally conductive and electrically insulating and the second part is electrically insulating and less thermally conductive than the first part or is not thermally conductive.

A tapered roller bearing includes an inner ring having a tapered raceway surface and a large-collar surface on a large-diameter side of the raceway surface, and tapered rollers. Each of the rollers has a large end surface guided by the large-collar surface. When R represents a set curvature radius of the large end surface and R.sub.BASE represents a base curvature radius from a vertex of a cone angle of each of the tapered rollers to the large-collar surface, the base curvature radius R.sub.BASE is 100 mm or less, and a ratio R/R.sub.BASE of the set curvature radius R to the base curvature radius R.sub.BASE is set to 0.90 or less. When R.sub.ACTUAL represents an actual curvature radius of the large end surface of each of the tapered rollers, a ratio R.sub.ACTUAL/R of the actual curvature radius R.sub.ACTUAL to the set curvature radius R exceeds 0.5.

To provide a rolling bearing having a hard film on an inner ring raceway surface and an outer ring raceway surface of the rolling bearing that improves peeling resistance of the hard film, shows the original property of the hard film, and suppresses the attackability to a mating material. A rolling bearing 1 has an inner ring 2 having an inner ring raceway surface 2a on an outer circumference, an outer ring 3 having an outer ring raceway surface 3a on an inner circumference, and rolling elements 4 that roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a. A hard film 8 includes a foundation layer formed directly on the inner ring raceway surface 2a or the outer ring raceway surface 3a and mainly formed of Cr and WC, a mixed layer having a gradient composition formed on the foundation layer and mainly formed of WC and DLC, and a surface layer formed on the mixed layer and mainly formed of DLC. In a roughness curve of a surface on which the foundation layer is formed, the arithmetical mean roughness Ra is 0.3 μm or less and the root mean square gradient RΔq is 0.05 or less.

To provide a rolling bearing having a hard film on an inner ring raceway surface and an outer ring raceway surface of the rolling bearing that improves peeling resistance of the hard film, shows the original property of the hard film, and suppresses the attackability to a mating material. A rolling bearing 1 has an inner ring 2 having an inner ring raceway surface 2a on an outer circumference, an outer ring 3 having an outer ring raceway surface 3a on an inner circumference, and rolling elements 4 that roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a. A hard film 8 includes a foundation layer formed directly on the inner ring raceway surface 2a or the outer ring raceway surface 3a and mainly formed of Cr and WC, a mixed layer having a gradient composition formed on the foundation layer and mainly formed of WC and DLC, and a surface layer formed on the mixed layer and mainly formed of DLC. In a roughness curve of a surface on which the foundation layer is formed, the arithmetical mean roughness Ra is 0.3 μm or less and the root mean square gradient RΔq is 0.05 or less.

A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.