HYDRAULIC CONTROL UNIT

摘要

A hydraulic control unit that even when the oil temperature is low and the viscosity of operating oil is high, inhibits any air suction by oil pump, thereby enhancing the efficiency of the oil pump. The hydraulic control unit comprises oil pan (25); oil pump (2); strainer (24) disposed between the oil pan (25) and the oil pump (2); pressure regulator valve (4) for regulating the pressure of operating oil fed from the oil pump (2) to a given pressure; oil cooler (5) for cooling the operating oil fed after having undergone the pressure regulation by the pressure regulator valve (4); and cooler bypass valve (6) with its input port (6a) connected to cooler feed oil channel (p2) for flow of the operating oil fed to the oil cooler (5), the cooler bypass valve adapted to, when the pressure of operating oil within the cooler feed oil channel (p2) is a given opening valve pressure or higher, bring the input port (6a) into communication with output port (6b), and further comprises cooler bypass oil channel (p3) connecting the output port (6b) of the cooler bypass valve (6) to suction oil channel (p1) between the suction port (21a,22a) of the oil pump (2) and the strainer (24).