High pressure fuel supply pump

摘要

In a high pressure fuel supply pump for transmitting rotation of a cam to a reciprocating plunger via a tappet and a retainer, a diametric force acting on the plunger is reduced. The pump includes the retainer disposed on the plunger and a return spring exerting an urging force on the retainer in a direction of the tappet. A clearance between a plunger leading end and a tappet bottom surface opposed thereto is set to be greater than a clearance between a retainer bottom surface and the tappet bottom surface opposed thereto, and a clearance between a retainer inside diameter section and a plunger peripheral surface section opposed thereto is set to be greater than a clearance between a retainer outside diameter section and a tappet inner wall opposed thereto.

主权项

1. A high pressure fuel supply pump, comprising:
a plunger driven by a tappet that follows rotation of a cam in an internal combustion engine to thereby make a reciprocating motion; and a retainer disposed on the plunger; a return spring for exerting an urging force to urge the retainer in a direction of the tappet; wherein: axial and diametric clearance is formed at a lock section of the retainer and the plunger in area between a leading end of the plunger and a bottom surface of the tappet opposed thereto so as to allow the plunger to be released from forces of the return spring and the cam acting thereon at a bottom dead center of the plunger, a bottom surface of the retainer and a bottom surface of the tappet opposed thereto being in abutment; the plunger includes a large diameter section and a small diameter section; the plunger further includes a stopper which contacts the large diameter section before the return spring becomes a free length when the plunger moves toward the tappet as the plunger receives the urging force of the return spring; and the lock section includes the retainer for bearing the return spring and an intermediate member fixed to the plunger, the intermediate member for locking the retainer.