Patent ID: 9121501
Filing Date: 2015-09-01
Classification: F16H

Abstract:
1. A continuously variable transmission, comprising: an input shaft; an output shaft; a toroidal continuously variable transmission; a differential gear unit; and a controller, the input shaft being a shaft to which engine output is inputted, the toroidal continuously variable transmission comprising: an input-side disk that is rotated and driven by the input shaft; an output-side disk that is concentric with the input-side disk and that is supported so as to be able to rotate freely with respect to the input-side disk; a plurality of power rollers that is held between the input-side disk and the output-side disk; a plurality of support members that supports the power rollers so as to be able to roll freely; an actuator that changes a transmission gear ratio between the input-side disk and the output-side disk by causing the support members to be displaced; a control unit that has an adjustment member that controls a direction and amount of displacement of the actuator in order to adjust the transmission gear ratio to a desired value; an input-side rotation sensor for detecting a rotational speed of the input-side disk; and an output-side rotation sensor for detecting a rotational speed of the output-side disk, the differential gear unit comprising: a first input section that has a plurality of gears and that is rotated and driven by the input shaft along with the input-side disk; and a second input section that is connected to the output-side disk, taking a rotation according to a speed difference between the first and second input sections, and transmitting the rotation to the output shaft, the controller being for controlling the change in the transmission gear ratio of the toroidal continuously variable transmission; and including: a first function that, by adjusting the transmission gear ratio of the toroidal continuously variable transmission and changing a relative displacement speed of the plurality of gears, converts a rotational state of the output shaft to forward rotation or reverse rotation with a stopped state in between while the input shaft is being rotated as is in one direction; a second function of calculating the transmission gear ratio of the toroidal continuously variable transmission from the rotational speed of the input-side disk that is found from the input-side rotation sensor, and the rotational speed of the output-side disk that is found from the output-side rotation sensor; and a third function of performing learning control that, with satisfying specified conditions for allowing learning as a condition, adjusts the transmission gear ratio of the toroidal continuously variable transmission to a state where the rotational speed of the output shaft becomes “0”, and then learns and stores a position of the adjustment member in this state as a position where the output shaft is stopped while the input shaft is rotating as is, wherein as the specified conditions for allowing learning for executing the learning control by the third function, an opening of an acceleration device being 0%; an engine rotational speed not fluctuating greater than a normal amount of fluctuation during idling; and the engine rotational speed being lower than a set upper limit rotational speed that was set to a value higher than a target idling speed that is set by the controller; are included, and wherein when the controller determines that all of the specified conditions are not satisfied, the controller prevents execution of the learning control by the third function.