Patent ID: 6830533
Filing Date: 2004-12-14
Classification: F16H,Y10T

Abstract:
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, comprising: a toroidal-type continuously variable transmission unit including: an input shaft driven and rotated by a drive source; an output shaft; at least a pair of disks supported so as to be relatively rotated with respect to each other and concentric with each other; a plurality of power rollers held between the pair of disks; a plurality of trunnions rotatably supporting the power rollers; and a hydraulic actuator including a pair of oil pressure chambers and causing each of the trunnions to generate a force proportional to a difference between oil pressures within the pair of oil pressure chambers, the toroidal-type continuously variable transmission unit changing a transmission ratio between the pair of disks by shifting the trunnions in the axial direction of pivot shafts as the swing centers of the respective trunnions by using the actuator; and, a differential gear unit including a combination of a plurality of gears, wherein relative shifting speeds between the plurality of gears of the differential unit are changed by adjusting the transmission ratio of the toroidal-type continuously variable transmission unit, thereby the continuously variable transmission apparatus switches the rotation state of the output shaft over between a forward rotation state and a backward rotation state with a stop state between them while rotating the input shaft in one direction by the drive source, and the control apparatus comprising: rotation speed control unit for controlling the rotation speed of the drive source; transmission ratio setting unit for setting the transmission ratio of the toroidal-type continuously variable transmission unit in order to coincide the rotation speed of the input shaft of the continuously variable transmission apparatus with the controlled rotation speed of the drive source; oil pressure measuring unit for measuring a pressure difference between the oil pressures of the pair of oil pressure chambers of the actuator; and, transmission ratio correcting unit operating in response to a deviation of a torque 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.