Patent ID: 8467946

Claim:
A control device for a continuously variable transmission that is connected to an internal combustion engine installed in a vehicle, the continuously variable transmission comprising a continuously variable transmission mechanism that modifies a speed ratio continuously and a subtransmission mechanism that is connected in series with the continuously variable transmission mechanism and includes, as vehicle forward advancing gear positions, a first gear position and a second gear position having a smaller speed ratio than the first gear position, the control device comprising: a rotation speed sensor that detects an engine rotation speed of the internal combustion engine; and a shift controller programmed to: perform a cooperative speed change in which the speed ratio of the continuously variable transmission mechanism is controlled in an opposite direction to a speed ratio variation of the subtransmission mechanism; determine if a rapid increase in the engine rotation speed has occurred during the cooperative speed change; and reduce a shift speed of the continuously variable transmission mechanism when the rapid increase has occurred with respect to an occasion when the rapid increase has not occurred, during the cooperative speed change when a shifting process for shifting the subtransmission mechanism from the first gear position to the second gear position is conducted.