Invention concerns a tappet for a valve in an internal combustion engine and comprises an essentially cup-shaped housing that fits over the shaft of the valve.
Cup-shaped tappets of this kind are generally known. Some are open and may or may not have hydraulic clearance compensation. Others are closed and have such compensation. Examples are disclosed in the German Patent Publication No. OS 3,506,730. Since the housings are metal, they confront the valve-activating mechanisms with a considerable accelerated mass. Accelerated mass is a highly critical parameter which the mass of the tappet participates in directly. The tappet's comparatively high mass subjects the valve mechanism, especially the spring, to inordinately high stress, especially at high speeds. Again, wear and tear in the vicinity of the tappet guides and at the bottom of the housing, where it comes into contact with the cam, increases with the accelerated mass of the valve mechanism.