Patent ID: 7160220

Claim:
A continuously variable transmission apparatus, comprising: an input shaft rotated and driven by a driving source; an output shaft; a toroidal continuously variable transmission; a gear-type differential unit including a plurality of gears; and a controller for controlling change of a transmission ratio of the toroidal continuously variable transmission; wherein the toroidal continuously variable transmission comprises: an input disc rotated and driven by the input shaft, an output disc supported so as to be relatively rotatable with respect to the input disc, a plurality of power rollers interposed between the input disc and the output disc, a plurality of support members rotatably supporting the respective power rollers, and an actuator having a pair of oil pressure chambers and displacing the support members so as to change the transmission ratio between the input disc and the output disc; the differential unit comprises: a first input portion rotated and driven by the input shaft together with the input disc, and a second input portion connected to the output disc, wherein a rotational movement which is obtained in accordance with a speed differential between the first and the second input portions is taken out and transmitted to the output shaft; and the controller performs the following functions (1) through (3): (1) a function of adjusting the transmission ratio of the toroidal continuously variable transmission so as to change a relative displacement speed of the plurality of gears contained in the gear-type differential, thereby converting a rotational condition of the output shaft between a forward-rotating condition and a reverse-rotating condition through a non-rotating condition while the input shaft continues rotating in a single direction; (2) a function of measuring a differential pressure between a pair of chambers constituting an actuator so as to calculate a torque actually passing through the toroidal continuously variable transmission; thereafter obtaining a deviation, from a target value, of the torque actually passing through the toroidal continuously variable transmission; and thereby adjusting the transmission ratio of the toroidal continuously variable transmission so that the torque passing through a toroidal continuously variable transmission attains the target value, and (3) a function of stopping the above function (2) in the case where the torque passing through the toroidal continuously variable transmission fails to become stable.