Hydraulic lifter

Abstract

An oil-containing hydraulic lifter for lash adjustment comprising relatively movable cylinder and plunger members defining a pressure chamber between their closed ends and a reservoir chamber within the plunger. Means are provided for rapid, one-way flow of the oil from the reservoir to the pressure chamber during outward movement of the plunger and for slow, one-way flow from the pressure to the reservoir chamber during inward movement of the plunger. A flexible, bag-shaped diaphragm extending into the reservoir chamber has its open, upper end sealed liquid tightly to the inner wall of the reservoir for sealing in the oil while expanding and collapsing with reciprocation of the plunger. The reservoir chamber has an increased diameter at that part where the diaphragm undergoes most of its expansion and collapse, thereby spacing the inner wall of the reservoir chamber from the diaphragm by a distance great enough to allow full expansion of the diaphragm in the expanding and collapsing operation thereof. The effect is to greatly increase the volumetric change exhibited by the oil within the reservoir chamber during the reciprocation of the plunger, thereby enhancing lash adjusting performance.