Patent ID: 8656892
Filing Date: 2014-02-25
Classification: F02M

Abstract:
1. A high-pressure pump for supplying fuel to a fuel rail connected with an injector, the high-pressure pump comprising: a pressurizing unit having a pressurizer chamber and a plunger for pressuring fuel, the pressurizer chamber having a volume that is changeable in accordance with displacement of the plunger; a discharging unit having a discharge valve, through which fuel pressurized in the pressurizer chamber is discharged to the fuel rail; a return flow channel that connects a downstream side of the discharge valve with an upstream side of the discharge valve such that the return flow channel allows fuel to return to the upstream side of the discharge valve, the upstream side and the downstream side of the discharge valve being defined relative to a first flow direction of fuel flowing through the discharging unit toward the fuel rail; a mechanical pressure relief valve that includes: a cup-like shaped spring seat that is provided within the relief valve element at an upstream side of the relief valve element in a second flow direction of fuel flowing through the return flow channel to the upstream side of the discharge valve, the spring seat having an outer edge urged against an internal upstream part of the relief valve element by the relief urging member, the spring seat defining a flow channel that allows fuel to flow therethrough; and a constant residual pressure valve that is provided within the spring seat, wherein: the constant residual pressure valve includes: the return flow channel is opened and closed in accordance with pressure of fuel flowing through the restrictor; the return flow channel is closed when pressure of fuel in the fuel rail becomes equal to or less than a predetermined pressure; the spring seat has a guide portion that is formed along an outer shape of the constant residual pressure valve element such that the guide portion limits a vortex flow generated at a position downstream of the constant residual pressure valve element in the second flow direction; the constant residual pressure urging member of the constant residual pressure valve is arranged inside of the a relief urging member of the pressure relief valve; and the spring seat includes a bent portion.