Patent ID: 8882475

Claim:
A plunger-type high-pressure fuel supply pump having a cylinder provided in a pump; a plunger slidably provided in the cylinder and configured to reciprocate in accordance with rotation of a cam; a fluid compression chamber defined by the plunger and the cylinder; an electromagnetic valve provided in a space defined between the compression chamber and a fluid intake channel; and a discharge valve provided in a space defined between the compression chamber and a fluid discharge channel; wherein the electromagnetic valve includes: an anchor movable in an axial direction together with a valve body; a back pressure chamber configured to be increased and decreased in volume by an action of the anchor; a fixed magnetic attracting surface opposing an attracting surface of the anchor with a first clearance interposed therebetween; a cylindrical magnetic area portion opposing an outer peripheral surface of the anchor with a second clearance interposed therebetween, the second clearance defining a fuel channel and also forming a magnetic circuit in cooperation with the anchor; a flange portion forming the attracting surface on the anchor; a first peripheral surface portion smaller than the flange portion in diameter; a cylindrical non-magnetic area portion having an outer surface with a constant diameter and opposing an outer peripheral surface of the flange portion with a third clearance interposed therebetween, the second clearance being provided on an outer periphery of the first peripheral surface portion; and a first fluid trap portion communicating with the back pressure chamber by the third clearance; and wherein the third clearance is larger than the second clearance in cross-sectional area.