Direct acting hydraulic valve lifter with integral plunger

Abstract

A direct acting hydraulic valve lifter of the type that is reciprocably journaled as in the cylinder head of an internal combustion engine so as to be engaged by a cam on an engine driven camshaft to control opening and closing movement of an associate valve. The lifter includes a follower body having a circular outer tubular wall with an inner integral web closely adjacent to one end thereof that terminates at a stepped bored integral depending piston, the one end thereof being closed by a disk cam engaging foot which forms with the piston and a surface of the web a fluid reservoir. A baffle, fixed to the plunger and to inner surface of the tubular wall, defines an oil supply passage which is adapted to receive fluid via a side port in the tubular wall and to be in flow communication with the fluid reservoir via an aperture in the web. A cup-shaped, closed end cylinder member slidably encircles the plunger to form therewith a hydraulic lash adjuster having a pressure chamber therein. In one enbodiment, a mechanical retainer is operatively secured to the tubular wall whereby to retain the cylinder member in unit assembly on the plunger. In a preferred embodiment, lubricating oil in the pressure chamber and in a leak-down flow path between the cylinder member and plunger and a one-way ball valve controlling flow into the pressure chamber are operative to hold the cylinder member in unit assembly on the plunger.