Patent ID: 8585542

Claim:
A control device for a vehicle continuously variable transmission, the vehicle continuously variable transmission being equipped with: a continuously variable transmission mechanism that allows a speed ratio to be continuously adjusted; and a subtransmission mechanism that is disposed in series with the continuously variable transmission mechanism, assumes a first gear position and a second gear position with a smaller speed ratio relative to a speed ratio corresponding to the first gear position as forward gear positions thereof, and switches from the first gear position to the second gear position or vice versa by selectively engaging or disengaging a plurality of frictional engagement elements, comprising: a transmission controller programmed so that: a cooperative speed change is executed when the gear position at the subtransmission mechanism is changed, the cooperative speed change comprising changing the speed ratio at the subtransmission mechanism and controlling a rate at which the speed ratio of the subtransmission mechanism changes while changing the speed ratio of the continuously variable transmission mechanism along a direction opposite from another direction in which the speed ratio at the subtransmission mechanism changes to keep pace with the change in the speed ratio at the subtransmission mechanism; and in an inertia phase occurring during switching the gear position at the subtransmission mechanism from the first gear position to the second gear position when a negative torque is input to the vehicle continuously variable transmission, the cooperative speed change is prohibited and a torque capacity at a disengagement-side frictional engagement element in the subtransmission mechanism is controlled so as to sustain a value substantially equal to zero without controlling the rate of change of the speed ratio at the subtransmission mechanism.