Variator disc and a method of fabricating the same
AssigneeKoyo Seiko Co., Ltd.
InventorsMasao Goto, Kiichiro Yamashita, Shinji Yasuhara
Life of this patent
Estimating the term…
Abstract
A blank for disc is heat treated for adjusting a surface hardness thereof to not less than Hv700. The blank has a spline hole thereof heated by high frequency heating while cooling a race thereof. Subsequently, the spline hole is subjected to slow cooling. Thus is obtained a disc having a surface hardness of not less than Hv700 at the race, and a surface hardness of not more than Hv600 at the spline hole, the disc wherein at least a thin portion is varied in hardness between a hardened layer of a bottom of the spline hole and a hardened layer of the race by an amount of not less than Hv20 per 1-mm depth.
Claims4
A disc for use in a variator of a toroidal continuously variable transmission comprising:
- a concave race at least on one side surface thereof for rolling movement of rollers;
- and
- a spline hole at its center which is meshed with an input shaft;
- said disc having a surface hardness of not less than Hv700 at said race;
- and
- having a surface hardness of not more than Hv600 at said spline hole;
- wherein at least at a thin portion between said spline hole and an inside circumferential edge of said race is varied in hardness between a hardened layer of a bottom of said spline hole and a hardened layer of said race by an amount of not less than Hv20 per 1-mm depth.
Dependencies are inferred from the claim text.