Koyo Seiko Company, Ltd.

Yasuharu Misada

Yoshihiro Ono

Shinji Yasuhara

Masao Goto

Yasuo Asai

Teruo Hoshino

Daiji Hiraoka

Yasuhiko Hasuda

Adrian P Lee

Jonathan Newall

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

A toroidal type continuously variable transmission includes a pair of discs ( ) in opposed relation, and a rotary element ( ) interposed in a toroidal clearance (S) defined between these discs ( ). Torque is transmitted between the pair of discs ( ) via the rotary element ( ). Sensing the velocity of the rotary element ( ) permits the determination of, for example, how much the rotary element ( ) slips on the discs ( ). This assists the prevention of heat-up of the rotary element ( ) and also provides an optimal traction between the rotary element ( ) and the discs ( ).

Toroidal type 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 toroidal type continuously variable transmission transmits a torque from an input disk to an output disk through a plurality of groups of rollers interposed between the input disk and the output disk. Respective carriages for the rollers are connected to one another by a connecting member. A hydraulic actuator collectively applies forces against torque transmission reactive forces respectively received by the rollers to the rollers through the connecting member and the corresponding carriages.

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Kashiwara, Japan

Yasuharu Misada