Shift control device and shift control method of vehicular continuously variable transmission

摘要

A hydraulic control circuit (100) that shuts off an oil passageway (A) so that the ratio between the shift pressure (PIN) and the belt clamping pressure (POUT) is not caused to be in a predetermined relationship even when a speed change ratio control valve (114) and/or a speed change ratio control valve (116) are not supplying/discharging hydraulic oil. Therefore, even if the speed change ratio control valve (114) and/or the speed change ratio control valve (116) cease supplying/discharging the hydraulic oil, the action of a thrust ratio control oil pressure (Pτ) output from a thrust ratio control valve (118) on a primary hydraulic cylinder (42c) is avoided. Thus, impairment of the continuity of control at the time of a shift of the continuously variable transmission (18) is prevented.