Patent ID: 7503869

Claim:
A speed change control apparatus for a toroidal CVT, comprising: a toroidal transmission member including an input disc, an output disc, and a roller to perform power transmissions by frictional engagement between the input disc and the output disc; a clamping device to clamp the roller by pushing the input and output discs; a speed change control unit to vary the inclination of the roller by offsetting the axis of rotation of the roller from the position in which the axis of rotation of the roller and the axis of rotation of the input/output disc intersect at a right angle, to thereby control a gear ratio; an offset amount detecting unit to detect an amount of the offset; a roller tangential force estimating unit to estimate a roller tangential force which is the force in the roller tangential direction as is determined on the basis of an input torque transmitted from the input disc to the roller and the contact position between the roller and the input disc; and an offset amount fluctuation estimating unit to estimate a fluctuation amount of the offset caused by a fluctuation of the clamping force of the clamping device, wherein the offset amount detected by the offset detecting unit is corrected based on the roller tangential force estimated in the roller tangential force estimating unit, so that the offset amount by the speed change control unit is controlled on the basis of the corrected offset amount, wherein the roller tangential force estimating unit estimates the roller tangential force on the basis of a value which is determined by dividing the input torque input to the toroidal transmission member by the radius of gyration of the contact point of the roller with the input disc or the output disc, and wherein the offset amount is also corrected based on the fluctuation amount estimated by the offset fluctuation amount estimating unit, so that the offset by the speed control unit is controlled on the basis of the corrected offset amount.