High-pressure fuel pump having a piston, a damper, and a pressure relief valve having a valve body and a spring

A high-pressure fuel pump, comprising:

• a housing including a chamber provided to compress fuel supplied thereinto, an inlet flow passage that communicates with the chamber to draw the fuel into the chamber through the inlet flow passage, and a discharge flow passage that communicates with the chamber to discharge the fuel out of the chamber through the discharge flow passage;
• a piston disposed in the housing and configured to linearly reciprocate to compress the fuel supplied into the chamber;
• a sleeve coupled to the housing and configured to support the piston and form a space for storing the fuel within the housing;
• a discharge valve disposed in the discharge flow passage of the housing and configured to open when a pressure of the fuel stored in the chamber is equal to or great than a first pressure;
• a pressure relief valve disposed in a relief flow passage which is formed in the housing and communicates with the discharge flow passage and the space, the pressure relief valve being configured to open when a pressure of the fuel supplied into the relief flow passage is equal to or greater than a second pressure;
• and
• a damper disposed in an upper portion of the housing, and configured to reduce pulsation of the fuel drawn thereinto through an inlet port and then supply the fuel to the inlet flow passage of the housing,
• wherein a first end of the piston compresses the fuel supplied to the chamber, the sleeve supports a second end of the piston, and the space is formed along a circumference of the second end of the piston,
• wherein the housing includes a damper aperture that directly communicates with the damper and the space, and the relief flow passage is formed to communicate with the discharge flow passage and the damper aperture,
• wherein the pressure relief valve comprises:
• a valve body inserted into and coupled to the relief flow passage, and having a through hole through which the fuel flows;
• an open-and-close member configured to open or close the through hole of the valve body;
• and
• a spring including a first end supported by the open-and-close member, and a second end supported in the damper aperture, the spring being elastically compressed when the pressure of the fuel drawn into the relief flow passage is equal to or greater than the second pressure, and
• wherein an insert depression is formed in the damper aperture to allow the second end of the spring to be inserted into and coupled to the insert depression.