Koyo Seiko Company, Ltd.

Yoshihiro Ono

Shinji Yasuhara

Masao Goto

Yasuharu Misada

Kazuo Rokkaku

Hisashi Harada

Yasuo Asai

Takao Tamagawa

Shoji Eguchi

Teruo Hoshino

Daiji Hiraoka

Yasuhiko Hasuda

Jonathan Newall

Adrian P Lee

In a toroidal continuously variable transmission, rolling contact portions of an input disc, an output disc, and rollerare formed of bearing steel, which contains C: 0.8-1.5 wt %; Si: 0.5-2.5 wt %; Mn: 0.3-2.0 wt %; Cr: 1.9-2.5 wt %; Mo: 0.3-1.0 wt %; and a total of 1.0 wt % or more of Si and Mo; with the balance being iron and unavoidable impurities. A residual austenite in a range of depth Z=1.0L, where L is the major axis of a contact ellipse of the traction contact portion, from the surface of the rolling contact portion is 15 wt % or less, and the hardness of the range is HRC 58-62 by tempering a blank with a predetermined shape at a temperature of 250&#xb0; C. or more after quenching the blank.

Toroidal continuously variable transmission and method for producing torque transmitting member thereof

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.

Toroidal continuously variable transmission

In a method of fabricating a variator disc, an outer periphery ( ) of the input disc (D ), with a spline hole ( ) thereof meshed with an input shaft ( ), is finished using the input shaft ( ) as a working reference. Subsequently, a race ( ) is finished with high precisions using the outer periphery ( ) as a working reference. There is an alternative method wherein a spline hole ( ) with a machining allowance is precisely formed by means of a broach (X) prior to the heat treatment of a blank (B); after hardening the blank (B) by the heat treatment, tooth flanks ( ) of the spline hole ( ) are precisely finished by means of a finishing broach (Y); and then, a race ( ) of an input disc (D ) is precisely finished using the tooth flanks ( ) as a working reference.

Method of manufacturing disk for variator

A continuously variable transmission including discs made of heat-resisting bearing steel, and rollers made of ceramics. The heat-resisting bearing steel contains 0.8-1.5 wt % of C, 0.5-2.0 wt % of Si, 0.3-2.0 wt % of Mn, 1.3-1.98 wt % of Cr, and 0.3-1.0 wt % of Mo, (Si&plus;Mo) being 1.0 wt % or more. Because the rollers are made of ceramics superior in heat resistance, the toroidal type continuously variable transmission, even if used under high load and high rotational speed, is free from occurrence of sticking between discs and rollers and damage of the raceway surfaces.

Toroidal type continuously variable transmission

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Gose, Japan

Yoshihiro Ono