Patent ID: 6953054

Claim:
A relief valve comprising: a valve housing in which a valve hole is disposed along an axis; a valve seat member fitted and fixed to an opening end portion of the valve hole, and in which pressurized oil discharged from a hydraulic pump is introduced to one end portion of a communication hole penetrating along an axis, a valve seat being formed in another end portion; a ball brought into contact with the valve seat so as to close the communication hole; a ball receiver holding the ball and slidably supported along an inner surface of the valve hole; a relief spring energizing the ball receiver in a direction in which the ball is brought into contact with the valve seat; and a relief hole relieving the pressure oil at the time of relieving the oil pressure, the relief hole being open in a radial direction of the valve hole, wherein an elastic body seal is provided so as to be sealed in an annular gap between the ball receiver and the valve hole, the elastic body seal being slidably in contact with at least one of an outer periphery of the ball receiver and an inner periphery of the valve hole such that the elastic body seal is not compressed in an axial direction of the ball receiver, and the elastic body seal comprises an oil seal provided with a seal lip in an outer periphery of a cored bar.