High pressure pump having unitary discharge and relief valve

摘要

A valve body is provided with a discharge relief portion. A relief valve outlet is formed in an end face thereof on a central axis of the valve body. Discharge valve inlets are point-symmetrically formed with respect to the central axis. A discharge valve outlet is formed in another end face thereof and relief valve inlets are point-symmetrically formed with respect to the central axis. A discharge valve outlet and the discharge valve inlets communicate with each other. A flow of fuel from a pressurization chamber to a fuel discharge port is restricted by a discharge valve member capable of closing the discharge valve outlet. The relief valve outlet and the relief valve inlets communicate with each other. A flow of fuel from the fuel discharge port to the pressurization chamber is restricted by a relief valve member capable of closing the relief valve outlet.

主权项

1. A high-pressure pump comprising:
a plunger configured to perform a reciprocating movement; a cylinder having a plunger accommodating hole for slidably accommodating the plunger, a pressurization chamber defined by an inner wall of the cylinder and an outer end wall of the plunger, a suction port configured to suction a fluid to the pressurization chamber, and a discharge port configured to discharge a fluid pressurized in the pressurization chamber; a housing having a first inner wall surface that forms a first discharge passage that communicates with the discharge port, a second inner wall surface that forms a second discharge passage that communicates with the first discharge passage and being larger in inside diameter than the first inner wall surface, and a stepped surface formed between the first inner wall surface and the second inner wall surface; a cylindrical member provided inside of the second inner wall surface; a valve body having a cylindrical portion accommodated inside of the cylindrical member, a flange portion extended from an end of the cylindrical portion in an outward radial direction and sandwiched between one end of the cylindrical member and the stepped surface, a valve-seat-forming portion closing the end of the cylindrical portion opposite to the pressurization chamber, a discharge valve seat formed on the wall surface of the valve-seat-forming portion opposite to the cylindrical portion, and a discharge valve passage that connects the discharge valve seat and the wall surface of the valve-seat-forming portion; a discharge valve member that is unseated from the discharge valve seat or seated on the discharge valve seat to open or close the discharge valve passage; and a discharge valve biasing portion that biases the discharge valve member in a direction in which the discharge valve member is seated on the discharge valve seat.