DE1157887B - Process for the production of hollow shaft poppet valves for internal combustion engines - Google Patents

Description

It is already known to manufacture hollow poppet valves by extruding one part of a blank with a blind hole to the valve stem that opens out on the press ram side and is filled with a metal core and subsequent upsetting of the non-extruded blank part to produce the plate, whereupon the filling core is pulled out and the plate opening is closed by a welded-in lid will.

According to the invention, this method is modified in such a way that that of the blind hole opening opposite end of the extruded blank compressed to the valve disk and the non-extruded Blank part forged together to form a closed shaft end after the filling core has been pulled out will.

In this way, with hollow forged valves, the plate that is subject to the greatest thermal stress is achieved is exposed, no longer has to be closed, which is particularly the case with sodium-filled Valve cones is beneficial. The invention allows the production of one-piece valves, wherein for the Filling the coolant only a very small opening must be made at the end of the shaft, which is afterwards can be closed in a known manner without difficulty.

In the method according to the invention, the bore extending through the shaft is in the area of the plate not widened; otherwise the filling core could not be pulled out of the shaft afterwards will.

The knowledge that a widening of the cooling space in the area of the plate, if necessary can be dispensed with is not new. A method is also known in which the shaft bore in the The area of the plate does not widen and this one at the massive end of an initially with a long one Blind hole to be provided blank is generated. The opening of the blind hole is also the same closed at the end of the shaft by radial displacement of material inwards. This is done in such a way that that either only an external thickening at the shaft end is produced by upsetting and then through Extrusion of the thickened end part is displaced radially inward in the direction of the plate; or by upsetting an outer and inner thickening of the shaft end is produced at the same time, and through the extrusion then essentially only reduces the shaft end part to the uniform shaft diameter brought.

The main difference is that in the known process extrusion is the last

of hollow shaft poppet valves

for internal combustion engines

Applicant:
Alfred Teves

Maschinen- und Armaturenfabrik KG,
Frankfurt / M., Rebstöcker Str. 41-53

Gerhard Kubera, Barsinghausen,
has been named as the inventor

Stage follows the creation of the plate and a upsetting of the shaft end and is limited to this end, in the method according to the invention, on the other hand, its first, the whole blank apart from the Shank end capturing stage. In this stage, a rod with a long blind hole is primarily created, wherein the thickening of the shaft end is the result of only partial extrusion, but not one Upsetting process. The known upsetting processes are not only cumbersome to carry out, but they also change the structure disadvantageously at the end of the shaft. This is especially true for in the event that extrusion is dispensed with and only compressed inwards. In addition, there is the heating zone to be strictly adhered to.

The process is illustrated in the drawing. It shows

Fig. 1 the blank with a metal core inserted into its blind hole,
Fig. 2 the first already known process step, namely the extrusion of the blank with the solid closed end first except for a remainder at the end where the blind hole opens,

Fig. 3 the blank after upsetting the valve disk,

Fig. 4 the blank after pulling out the filling core and

Fig. 5 the fully forged valve.

The diameter of the blank is to be chosen so that the solid end as shown in Fig. 3 becomes a Can compress plate into which the filling core extends without widening in this.

309 749/128

The open end of the blank, which is not deformed during the extrusion process, retains its original wall thickness, which is so great that when forging this end together after pulling it out of the filling core, the bore in the area of the shaft end is closed and the outer diameter at this point corresponds to that of the rest of the valve stem.

Claims (1)

PATENT CLAIM: Process for the production of hollow shaft poppet valves by extrusion of one part of a blank with a blind hole opening out on the ram side and filled with a metal core for the valve shaft and subsequent upsetting of one end to form the valve head, characterized in that the end of the extruded blank opposite the blind hole is upset to form the valve head and the non-extruded end portion of the blank is forged together to form a closed shaft end after the filling core has been withdrawn. Considered publications:
U.S. Patent No. 3,016,601. 1 sheet of drawings