Tappet

#The invention concerns a tappet especially for transferring a cam or eccentric generated oscillating movement onto a sliding part such as a gas exchange valve or a pump piston, which has a circular-shaped section, which includes an outer casing for guiding in form and a base on the top, the outer side of which provides the contact area for the cam. A dome-shaped socket with a contact surface for the sliding part extends from the inner side of the base.

#A tappet of this type is disclosed in FIG. 13 of the WO 95/00749. This possesses a circular-shaped section which has a one-piece dome-shaped socket extending from the topside into the interior. A separate base is secured to the topside of the socket.

#The disadvantage of this construction is that the one-piece construction of the circular-shaped section with the dome-shaped socket is very difficult to manufacture, considering the current state of technology in the field. The length of the socket alone is limited by manufacturing and technical considerations. Attaching a separate base to the socket securely also presents difficulties in itself.

#The function of the invention is described in more detail in connection with of the drawing. The single illustration shows a longitudinal cross-section through a tappet, here for contact of a pump piston in an injection pump for fuel of either a quality or quantity controlled internal combustion engine.

#FIG. 1 shows a tappet (1) for a use such as that noted in the previous paragraph. This tappet (1) can, however, also be utilized for movement of a gas exchange valve in an internal combustion engine. The tappet (1) has a circular section (2) with an outer casing (3). By means of this construction, the tappet (1) is incorporated into a longitudinal guide not displayed here. In the top area (4), the tappet (1) includes a base (5) having a disk-like geometry. The base (5) has an outer top side (6). This serves as a contact face for an eccentric or cam, not illustrated here. The base (5) also has an inner side (7). On this lies a dome-shaped socket (9) with a ring-shaped end face (8). The socket (9) extends along a large part of the length of the circular-shaped section (2) and has a contact surface (10) for a pump piston on the end furthest from the base. If the tappet (1) is used in the valve drive of an internal combustion engine, a gas exchange valve stem would be located at the contact surface (10).

#As can easily ascertained from the illustration, the circular shaped section (2) and the base (5) are manufactured in one piece, for example, in an extrusion mold or a sheet metal forming procedure. The socket (9) is constructed as a separate component and is found of a thin walled material such as sheet metal.

#From the end face (8) of the socket (9), a ring collar (11) extends in the direction of the inner surface (12) of the circular section (2). Through the ring collar (11), the socket (9) may be simply mounted onto the inner surface (12) of the circular section (2).