Patent ID: 8914200

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 wrapped around the primary pulley and the secondary pulley so as to control a gear ratio determined by a running radius ratio of the belt on the pulleys 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 control means for oscillating the secondary hydraulic pressure and monitoring 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 condition, and controlling the actual secondary hydraulic pressure to decrease on the basis of an estimation of the belt slip condition to maintain a predetermined belt slip condition; and a belt slip control permission determining means for permitting the belt slip control means to perform a belt slip control when a change speed of the gear ratio of the belt type continuously variable transmission is less than a predetermined value at which the oscillation component included in the actual gear ratio and a variation in the actual gear ratio are separated from each other.