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%.
Claims8
A rolling bearing comprising races composed of an outer race and an inner race and rolling elements which are provided between the outer race and the inner race such that the rolling elements rotate freely, wherein at least said inner race is made of a titanium alloy and said rolling elements are made of a corrosion-resistant material.
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 steps of:
- (a) selecting at least one from the group consisting of β type titanium alloy and (α+β) type titanium alloy as a race material;
- (b) heating and keeping said race material at the temperature falling within the range of β phase temperature of not lower than β phase transition point to effect solution treatment such that the phase of the texture of said race material is converted to β phase;
- (c) rapidly cooling said race material so that the texture of said race material normally stays in 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 α phase which is harder than β phase and the α phase to be finely deposited in β phase;
- (e) subjecting said race material to aging at a predetermined temperature lower than β phase transition point, whereby nuclei of α phase are formed and grown and the α phase is finely deposited in β phase;
- and then
- (f) machining said race material to a race.
Dependencies are inferred from the claim text.