To prevent wear at the upper portion of a reciprocating plunger by providing an annular groove on the outer peripheral surface at the leading end of the plunger.
A fuel supply pump is provided with a plunger 23 reciprocating within a barrel 45 upon receipt of a thrust force applied to a base end portion thereof such that fuel in a pump chamber is pressurized. The plunger 23 is provided with an annular groove 71 on the outer peripheral surface at the leading end portion. When the thrust force is applied to the base end portion of the plunger 23, it can be supported at a high pressure by maintaining the fuel within the annular groove 71 under high pressure. Even when the thrust force acts biasedly, the plunger 23 can be prevented from being inclined.
TAKAMINE HIROYUKI
KASHIBA SHIGERU
AOKI FUSUO
Next Patent: HIGH PRESSURE FUEL SUPPLY PUMP