Patent ID: 8892318

Claim:
A control device for a belt type continuously variable transmission, comprising a primary pulley for receiving an input from a drive source, a secondary pulley for providing an output to a drive wheel, and a belt wound around the primary pulley and the secondary pulley, to control a gear ratio determined by a ratio of a diameter of the pulleys where the belt is wound around by controlling a primary hydraulic pressure to the primary pulley and a secondary hydraulic pressure to the secondary pulley, the device further comprising: a belt slip controller configured to oscillate the secondary hydraulic pressure and monitor a phase difference between an oscillation component included in an actual secondary hydraulic pressure and an oscillation component included in an actual gear ratio to estimate a belt slip state, and control the actual secondary hydraulic pressure to decrease on the basis of the estimation to maintain a predetermined belt slip state; and an oscillation amplitude setter configured to set an oscillation amplitude of the secondary hydraulic pressure small when the gear ratio is a high gear ratio compared with when the gear ratio is a low gear ratio, in a case of oscillating the secondary hydraulic pressure in the belt slip control.