RELIEF VALVE MECHANISM AND FUEL SUPPLY PUMP COMPRISING THE SAME

摘要

To provide a fuel supply pump capable of preventing cavitation damage at a relief valve seat part under high pressure, and also capable of reducing pressure loss of a relief valve upon releasing abnormal high pressure.SOLUTION: A relief valve mechanism comprises: a relief valve; a seat surface formed with a seat part on which the relief valve is seated, and inclined at a first angle to a valve axis direction; a downstream side inner diameter enlarged part formed so as to connect to the seat surface on a downstream side with respect to the seat part, and formed so as to enlarge from a lower end of the seat surface to a radially outward side with respect to the seat surface; and a downstream side end surface formed from a lower end of the downstream side inner diameter enlarged part to the radially outward side.SELECTED DRAWING: Figure 6