MULTIFUNCTION RELIEF VALVE AND AIRPLANE EMERGENCY HYDRAULIC POWER SOURCE UNIT HAVING THE SAME

摘要

A multifunction relief valve 1 includes: a relief chamber 2 having an introduction port 7 and a relief port 8 for introducing and relieving pressure fluid; a back pressure chamber 3 formed on one end side of the relief chamber 2; a piston 4 which is movably provided in the back pressure chamber 3 and divides the back pressure chamber 3 into a first back pressure chamber 3a and a second back pressure chamber 3b; a first spring 5 which is provided in the first back pressure chamber 3a and exerts a biasing force in a direction in which the relief port 8 is closed; a second spring 6 which is provided in the second back pressure chamber 3b and biases the piston 4 in the direction in which the relief port 8 is closed; and a pilot pressure supply port 9 formed in the first back pressure chamber 3a. The pressure fluid introduced into the first back pressure chamber 3a via the pilot pressure supply port 9 changes the relief pressure.