HYDRAULIC CONTROLLER OF AUTOMATIC STEPLESS SPEED CHANGER FOR VEHICLE

PURPOSE:To enable upshift or downshift operation of a speed changer to be promptly performed, by inputting a shift signal oil pressure by means of a primary regulator valve so as to level up the output line pressure of the speed changer at its shift running time. CONSTITUTION:A speed reduction control mechanism 50, outputting a shift oil pressure signal to a primary regulator valve 30 at rapid upshift running time and/or rapid downshift running time, controls the output line pressure to be raised up at the shift running time. Accordingly, effective pressure receiving area of the hydraulic servo of an input pulley 150 can be equally set to the effective pressure receiving area of the hydraulic servo of an output pulley 160 in a V-belt type stepless speed changer 140, and the V-belt type stepless speed changer can be formed in compact size and light weight. While, at shift running time, the primary line pressure supplied to the hydraulic servo of the pulley in the side increasing an effective diameter can be raised up only at the shift running time, thus an up or downshift can be promptly operated.