Patent ID: 8701631
Filing Date: 2014-04-22
Classification: F02D,F02M,F04B,F16K,Y10T

Abstract:
1. A pressure relief valve for a high pressure pump, in which a fuel flow from a high pressure side to a low pressure side is allowed but a fuel flow from the low pressure side to the high pressure side is prohibited, comprising: a valve seat formed at an inner wall of a fuel return passage provided between the high pressure side and the low pressure side; a valve member for closing the fuel return passage when the valve member is seated on the valve seat, and for opening the fuel return passage when the valve member is separated from the valve seat; and a biasing means for biasing the valve member toward the valve seat at a predetermined biasing force, wherein the valve member comprises; a shaft portion extending in an axial direction of the fuel return passage toward the valve seat, a forward end of the shaft portion being seated on and/or separated from the valve seat; a pressure receiving portion extending from a rear end of the shaft portion in a radial outward direction toward an inner wall of the fuel return passage, so that a fuel inlet chamber is formed in the fuel return passage between the valve seat and the pressure receiving portion; a guide portion extending from an outer periphery of the pressure receiving portion in an axial direction of the fuel return passage, which is opposite to a direction toward the valve seat, wherein the guide portion slides on the inner wall of the fuel return passage; a notched portion formed at an outer wall of the guide portion so as to form an outer-surface passage for communicating the fuel inlet chamber to the fuel return passage at a downstream side of the valve member; a fuel inlet port having one end opened at the shaft portion or the pressure receiving portion and another end opened to the fuel return passage at the downstream side of the valve member, so that the fuel inlet port communicates the fuel inlet chamber to the fuel return passage at the downstream side of the valve member.