Patent ID: 8434508

Claim:
A relief valve comprising: a valve body including a first port through which fluid flows in the relief valve and a second port through which the fluid is discharged from the relief valve; a sleeve arranged so as to be slidable within the valve body and formed in a cylindrical shape having an inlet being communicatable with the first port and an outlet being communicatable with the second port; a valve being slidable within the sleeve by receiving a fluid pressure of the first port flowing through the inlet in order to establish a closing state at which the outlet is closed by the valve and an opening state at which the outlet is opened, the valve positioned so as to approach the inlet in the closing state and positioned so as to be distant from the inlet in the opening state; a biasing member applying a biasing force to the valve in a direction against the fluid pressure of the first port; and a valve position adjusting mechanism actuated for operating the fluid pressure of the first port so as to act on the sleeve in a direction of the biasing force of the biasing member and changing the position of the sleeve relative to the valve body by turning on or off the operation of the fluid pressure of the first port so as to act on the sleeve.