Nsk Corporation

Toshiro Toyoda

Eiji Inoue

Takashi Imanishi

Hiroki Nishii

Tomohiro Inoue

Takumi Sinojima

Norihisa Kobayashi

Yuji Shimomura

Hirotaka Kishida

Hiroyasu Yoshioka

Shin Yamamoto

Toshihiko Sato

Sachiko Noji

Tomomi Yamaguchi

The present invention provides a toroidal continuously variable transmission capable of reducing loss which occurs at a bearing and achieving range-widening at low cost with easy disc machinability. In the toroidal continuously variable transmission, a bearing ringof a ball bearingis formed at a small end surfaceof an inner disc. Further, at least a part of the bearing ringis axially overlapped with a traction surfacewhich is a boundary surface between a power roller and the inner disc. Further, a position adjustment memberis inserted between support postsand a bearing ring facing to the disc(the other bearing ring of the ball bearingopposed to the bearing ringof the small end surface).

Toroidal continuously variable transmission

A toroidal continuously variable transmission of the present invention comprises: input side disks () and output side disks () being supported concentric with each other such that the disks can rotate freely; a trunnion () that comprises end sections () on both ends on which tilt shafts () that are concentric with each other are provided, and a support beam section () that extends between both end sections (), the trunnion () being capable of pivotally displacing around the tilt shafts (); a thrust rolling bearing (); and a power roller () that is supported to the inside surface of the trunnion () by way of the thrust rolling bearing () such that it rotates freely; wherein the support beam section () comprises an inside surface having a cylindrical convex surface (); the thrust rolling bearing () comprises an outer race () having an outside surface with a concave section () that fits with the cylindrical convex surface () of the support beam section (), and a plurality of rolling bodies () that are located between the power roller () and a track of an outer race (); and the concave section () of the outer race () has side surface sections () on both sides in the width direction, fits with the cylindrical convex surface () by the cylindrical convex surface () coming in contact with both side surface sections ().

In this toroidal continuously variable transmission unit, a carrierand a discis brought into direct friction contact with each other, and power transmission between the carrierand the discis implemented by friction force. Because of this, the necessity of machining a gear or claw on the disc or carrier, which has conventionally be done, is obviated, whereby a manufacturing process can be shortened and manufacturing costs can largely be reduced.

Toroidal continuously variable transmission unit and continuously variable transmission

A sleevemaking up a gear ratio control valveis driven by not only a stepping motorbut also a secondary actuator. Pressure oil is made free to be introduced into the secondary actuatorthrough a manual oil pressure switching valvewhich is switched over by a gearshift. Then, when the gearshift is operated from a non-running state to a running state, a gear ratio of a toroidal type continuously variable transmission is corrected by a predetermined amount by driving the sleeveby the secondary actuator. As a result, while improving characteristic of a vehicle when starting from rest, the vehicle can be prevented from being reduced in speed unintentionally excessively even when the gearshift is operated while running.

Continuously variable transmission system

A continuously variable transmission apparatus includes a toroidal-type continuously variable transmission, a planetary gear type transmission and a clutch apparatus that connects the toroidal-type continuously variable transmission and the planetary gear type transmission. The clutch apparatus includes: a low speed clutch engaged for realizing a low speed mode and disengaged for realizing a high speed, a high speed clutch engaged for realizing the high speed mode and disengaged for realizing the low speed mode and a controller. The controller controls the transmission ratio of the toroidal-type continuously variable transmission so that rotational speeds of members connected via the clutch apparatus equals with each other, and then disengages the one of the low speed clutch and the high speed clutch after engaging the other.

Continuously variable transmission apparatus

A control apparatus for controlling transmission ratio of a toroidal-type continuously variable transmission unit of a continuously variable transmission apparatus, the continuously variable transmission apparatus has: a toroidal-type continuously variable transmission unit, which changes a transmission ratio between pair of disks by shifting trunnions in the axial direction of pivot shafts by using actuators; and, a differential unit of a gear type including a combination of a plurality of gears, the control apparatus having: rotation speed control unit; transmission ratio setting unit; oil pressure measuring unit; and, transmission ratio correcting unit operating in response to a deviation of a pressure difference between a measured value by the oil pressure measuring unit and a target value of a torque passing through the toroidal-type continuously variable transmission unit, and adjusting the transmission ratio of the toroidal-type continuously variable transmission unit so as to eliminate the deviation.

Apparatus and method for controlling transmission ratio of toroidal-type continuously variable transmission unit for continuously variable transmission apparatus

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Kanagawa, Japan

Toshiro Toyoda