Rolling bearing
AssigneeNsk Ltd.
InventorsKouji Ueda, Manabu Ohori
Life of this patent
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Abstract
The present invention provides a rolling bearing having an excellent corrosion resistance and toughness which can fairly operate at a high rotary speed. At least the inner race is formed by a titanium alloy, and the rolling elements are formed by ceramics. Alternatively, at least one of the inner race and the outer race is formed by a β type titanium alloy. The percent cold working of the β type titanium alloy is predetermined to not less than 20% or a range of from 5 to 20%. The cold working is followed by shot peening. Further, the surface hardness Hv is predetermined to not less than 600. The volumetric ratio of residual β phase in the β type titanium alloy is predetermined to a range of from 30 to 80%.
Claims4
A method for producing a rolling bearing, which comprises preparing at least one race selected from the group consisting of an outer race and an inner race according to a method which comprises:
- (a) selecting at least one member selected from the group consisting of a β titanium alloy and a (α+β) titanium alloy as a race material;
- (b) heating and keeping said race material at a temperature falling within the range of a β phase temperature of not lower than a β phase transition point to effect solution treatment such that the phase of the texture of said race material is converted to the β phase;
- (c) rapidly cooling said race material so that the texture of said race material normally stays in a β single phase;
- (d) subjecting said race material to plastic working so that it is shaped as desired and given work strain, which enables formation of nuclei of the α phase which is harder than the β phase and the α phase to be finely deposited in the β phase;
- (e) subjecting said race material to aging at a predetermined temperature lower than the β phase transition point, whereby nuclei of the α phase are formed and grown and the α phase is finely deposited in the β phase;
- and then
- (f) machining said race material to form a race.
Dependencies are inferred from the claim text.