OIL PRESSURE CONTROL DEVICE FOR POWER TRANSMISSION DEVICE

摘要

PURPOSE:To improve specific fuel consumption by controlling a displacement control means of a variable displacement type hydraulic pump in link motion with a pressure control valve for controlling oil pressures supplied to a hydraulic type clutch device interposed between an engine and a continuously variable transmission (CVT). CONSTITUTION:A power transmission device in which revolution inputted from an engine P via a hydraulic type clutch device C is continuously changed with a CVT and outputted to a load device L is equipped with a hydraulic control device including a variable displacement type hydraulic pump SP1 driven by the engine P. In this case, a clutch control means CC consisting of a pressure control valve CC' and a signal oil pressure generating means CS for generating signal oil pressures corresponding to the control condition of the valve CC' is arranged between a main hydraulic circuit ML for supplying pressure oil from the hydraulic pump SP1 to the clutch device C and the clutch device C. When the clutch is disengaged, a displacement control means SP2 is made to control so that the delivery pressure of the hydraulic pump SP1 is lowered.