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.

Systems and methods are provided for a compound bearing assembly including an offset coupler supporting an inner bearing and an outer bearing for distributing a rotational loading of the compound bearing assembly. In some embodiments, at least one of the bearings comprises a bearing cage with a plurality of elongated openings for receiving a respective plurality of balls. The compound bearing assembly is configured to support a drive shaft of a supercharger system of a vehicle or some other rotational system.

Systems and methods are provided for a compound bearing assembly including an offset coupler supporting an inner bearing and an outer bearing for distributing a rotational loading of the compound bearing assembly. In some embodiments, at least one of the bearings comprises a bearing cage with a plurality of elongated openings for receiving a respective plurality of balls. The compound bearing assembly is configured to support a drive shaft of a supercharger system of a vehicle or some other rotational system.

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.

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.

A system is provided that may include a generator or alternator. A ceramic bearing assembly is within the alternator or generator. The ceramic bearing assembly may include one or more ceramic rolling elements formed of a ceramic material not including metal and disposed between a metallic inner race and an outer race of the ceramic bearing assembly.

A system is provided that may include a generator or alternator. A ceramic bearing assembly is within the alternator or generator. The ceramic bearing assembly may include one or more ceramic rolling elements formed of a ceramic material not including metal and disposed between a metallic inner race and an outer race of the ceramic bearing assembly.

A metal foam ball, several millimeters in diameter, is manufactured to have an open-pore structure to absorb fluid (e.g., gas and liquid) such as water or lubricant. As an example, a copper foam ball is manufactured via a freeze casting method using prepared oxide powder slurry where a spherical silica gel mold is used to freeze the slurry, which is subsequently dried at low temperature in vacuum and then sintered at high temperature. For improved oxidation, copper alloy foam ball or copper foam ball coated with tin can also be manufactured through the same method. For improved strength, steel, copper-nickel alloy, or titanium foam ball can also be manufactured through the same method.

A metal foam ball, several millimeters in diameter, is manufactured to have an open-pore structure to absorb fluid (e.g., gas and liquid) such as water or lubricant. As an example, a copper foam ball is manufactured via a freeze casting method using prepared oxide powder slurry where a spherical silica gel mold is used to freeze the slurry, which is subsequently dried at low temperature in vacuum and then sintered at high temperature. For improved oxidation, copper alloy foam ball or copper foam ball coated with tin can also be manufactured through the same method. For improved strength, steel, copper-nickel alloy, or titanium foam ball can also be manufactured through the same method.