Abstract: For extension of service lives of rollers and discs of a toroidal continuously variable transmission, input discs, output discs and rollers are formed of a heat-resisting bearing steel. At least a roller has its peripheral surface subjected to a shot peening for achieving a compressive residual stress of 0.6 to 1.2 GPa and a hardness of HRC 63 to 66 at the outermost surface.

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.

Abstract: A one-way clutch comprises a plurality of rollers, a retainer having the same number of roller pockets as rollers, a cylindrical shell having the same number of cam grooves as rollers, and springs for normally biasing the rollers toward the cam grooves. The cam grooves are provided at the axially intermediate portion of the shell. The shell is provided at one end with a radially inwardly-turned flange and at the other end with a cylindrical boss portion having a smooth inner surface free of cam grooves. The retainer includes a pair of annular portions at either end and an axially intermediate portion provided with roller pockets. The annular portion which is inserted into the boss portion of the shell has a smooth cylindrical outer surface dimensioned to be pressingly fitted to the boss portion. Thus there are no gaps between the retainer and the shell at the boss portion of the shell, thereby sealing that end of the shell and preventing the outflow of grease and the entry of dust.