Abstract: The present invention is directed to rolling type bearings having an enhanced resistance to acoustic performance degradation that are best suited for incorporation into information systems as well as methods of producing such rolling type bearings. The resistance to acoustic performance degradation is achieved by improving the microstructure of bearing steel to make it possible to prevent the formation of indentations which can result from prolonged exposure to high-temperature conditions, dropping or other impact loads. A rolling type bearing of the invention comprises outer and inner rings and rolling elements disposed therebetween, at least the outer and inner rings being made of a steel material whose microstructure consists essentially of a mixture of ferrite and cementite.

Abstract: A bearing steel part for a rolling bearing having a core portion and a high hardness region formed by carburization to cover the core portion is provided in which the composition of at least the core portion contains at least 0.15 wt. % and at most 0.20 wt. % of C, at least 4 wt. % and at most 7 wt. % of Cr, at least 1 wt. % and at most 3 wt. % of Mo, and at least 0.4 wt. % and at most O.9 wt. % of V, with Fe group as base material. Therefore, the bearing steel part for the rolling bearing can be obtained having a better rolling contact fatigue life realized by increasing the core hardness of carburized steel and also having a high fracture toughness value.

Abstract: A rolling contact bearing, in particular, a carbonitrided bearing mainly used for automobile transmissions, being intended that the steel for the bearing contains less amounts of alloy ingredients to keep its good cold working performance, that carbonitriding time is shortened to reduce production costs, and that its rolling fatigue life is extended, in particular, under lubrication with foreign elements.At least the bearing race member of the bearing made of a medium carbon steel consisting essentially of, by weight, 0.4 to 0.8% of C, 0.4 to 0.9% of Si, 0.7 to 1.3% of Mn and 0.5% or less of Cr is formed by cold working. The bearing race member is provided with case-hardened layers thereon obtained via carbonitriding, followed by quenching and tempering. Retained austenite in the case-hardened layers is kept in the range of, by volume, 20 to 40%, and the core portion of the bearing race member has a hardness of HRC58 or less.

Abstract: A bearing race member composed of steel containing 0.60 to 0.85% carbon by weight, 0.5 to 1.0% by weight in a single content or total contents of Si and Al, and 13 ppm or less oxygen, wherein said bearing race member is quenched and subsequently tempered to contain 15% or less retained austenite therein. Even though basically made of structural carbon steel, the bearing race member has a long life equal to that of high-carbon chromium bearing steel and is superior in dimensional stability and crack fatigue strength.

Abstract: An improved rolling bearing is proposed which has a longer life under heavy load and under lubrication with oil containing foreign matters. Its bearing rings and rolling elements are made of carburized steel having an oxygen content of 15 PPM or less and have a deeper surface hardened layer and a higher core hardness. It has a longer life even under lubrication with oil containing foreign matters.

Abstract: A method of splitting bearing rings in a direction obliquely crossing their axes. This method comprises forming a notch of substantially V-shaped cross-section in the inner or outer peripheral surface of a bearing ring obliquely or in a V-direction, or forming a notch of substantially V-shaped cross-section in an end surface of a bearing ring at a predetermined angle with respect to the surface, heat-treating the bearing ring, and exerting wedge stress along the notch by a wedge type press-breaking tool.