Patent ID: 9651162
Date: 2017-05-16
CPC Classifications: F16K,Y10T

Claim:
1. A relief valve comprising: a valve element; a body portion in which a valve chamber that accommodates the valve element is formed; an inflow channel that guides a fluid flowing in from an upstream side to the valve chamber; a valve hole that allows the valve element to be inserted therein, and shuts off passage of the fluid between the valve hole and the valve chamber by contacting the valve element; an outflow channel that guides the fluid flowing into the valve hole from the valve chamber to a downstream side; and a spring that applies an urging force in a direction to bring the valve element into contact with the valve hole to the valve element, wherein an annular convex portion having an annular shape in plan view that is convexed in a direction in which the valve element moves away from the valve hole along a center axis of the valve hole and that is arranged around the valve hole is formed in the valve chamber, an annular concave portion having an annular shape in plan view that is concaved in the direction in which the valve element moves away from the valve hole along the center axis of the valve hole is formed in the valve element, in a shut-off state in which the valve element is in contact with the valve hole, the annular convex portion is accommodated in the annular concave portion, and an annular channel having an annular shape in plan view that extends in a direction of the center axis is formed between an outer peripheral surface of the annular convex portion and an inner peripheral surface of the annular concave portion, a sectional area of the annular channel is not changed irrespective of a position of the valve element ranging from a position in the shut-off state to a position in which the annular convex portion is not accommodated in the annular concave portion when the valve element moves away from the valve hole along the center axis due to the increased fluid pressure of the fluid in the valve chamber, and the flow rate of the fluid flowing into the valve hole from the valve chamber is regulated by the annular channel when the valve element moves away from the valve hole.