HYDRAULIC CONTROLLER OF AUTOMATIC STEPLESS SPEED CHANGER FOR VEHICLE

PURPOSE:To improve conversion efficiency of a speed changer, by inputting a shift signal oil pressure by means of hydraulic controller so as to level up the primary line pressure, which is output in a rapid shift of the V-belt type stepless speed changer at its running operation. CONSTITUTION:Turning on an up or down solenoid 55, 56 by a shift up or down signal from an electronic control circuit, a spool 53 of a speed reduction ratio control valve 51 is vertically moved to generate the governor pressure in an oil passage 6A, while said pressure is applied to a primary regulator valve 30 as a shift signal oil pressure through a check valve 34, and the line pressure, being levelled up, is supplied to the hydraulic servo of an input pulley 150 at upshift time while to the hydraulic servo of an output pulley 160 at downshift time, thus a V-belt type stepless speed changer 140 can be rapidly shifted. While, at the times other than the shift time, only a low level of the line pressure is necessary, and an engine power consumed by an oil pump 20 can be reduced.