CONTROLLER AND CONTROL METHOD OF BELT-TYPE CONTINUOUSLY VARIABLE TRANSMISSION FOR VEHICLE

PROBLEM TO BE SOLVED: To achieve improvement in control stability of secondary oil-pressure while ensuring estimation accuracy of a belt slip state during belt slip control. SOLUTION: A belt-type continuously variable transmission mechanism 4 has a primary pulley 42, a secondary pulley 43, and a belt 44. A controller of the belt-type continuously variable transmission mechanism includes a secondary hydraulic control means 101 that determines a command secondary oil-pressure by hydraulic feedback control based on a deviation between a target secondary oil-pressure and an actual secondary oil-pressure, a belt-slip control means 102 that vibrates the secondary oil-pressure so as to estimate a belt-slip state by monitoring a phase difference θ between a vibration component included in the actual secondary oil-pressure and a vibration component included in an actual change gear ratio and determines the command secondary oil-pressure by phase-difference feedback control, which maintains a prescribed belt-slip state, on the basis of the estimation, and a switching means (deviation switching part 92d, vibration switching part 93c, and correction-amount switching part 94h) that switches hydraulic control between the secondary hydraulic control means 101 and the belt-slip control means 102 by the determination based on belt-slip control permission conditions. COPYRIGHT: (C)2011,JPO&INPIT