Metal working – Means to assemble or disassemble – Puller or pusher means – contained force multiplying operator
Patent
1986-03-20
1987-10-20
Larson, Lowell A.
Metal working
Means to assemble or disassemble
Puller or pusher means, contained force multiplying operator
72377, B21K 130
Patent
active
047004460
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for manufacturing a synchronising component, provided with a short toothing having undercut teeth, for shift transmissions by precision forging. The teeth, the radially inner side of which lies against a common cylindrical surface and the base of which is placed on a common lower plane surface, is first manufactured with parallel tooth flanks and then subjected to final clenching.
Such a process for manufacturing force-transmitting coupling components having claws or pockets is known from DE Al No. 31 34 857. In that specification claws are produced during preliminary forging the head, surfaces of which are manufactured oversize, at least along their edges that are common with the coupling surfaces. By means of a subsequent calibrating stroke the desired obliquity of the coupling surfaces is achieved. During calibration, the claws can be supported between forging-die surfaces extending transversely to the coupling surfaces.
It is also known (German Auslegeschrift No. 2 040 413) when manufacturing wedge-toothed wheels having undercut teeth to manufacture, by rough pressing, teeth having parallel tooth flanks which are then finally clenched, with the formation of a roof-shape. The obliquity of the tooth flanks for achieving the undercut tooth shape in this case is produced using a special bevelling device, with which radially movable punches enter into the tooth spaces.
The use of the known forging process for the manufacture of synchronising components, provided with a short toothing, for shift transmissions is limited at least in the case of high precision requirements and in the case of very small synchronising components. Because the side flanks of the dogs forming the coupling surfaces are shaped freely by clenching the extra material of the head, the precision of the formation of the coupling surfaces cannot readily be increased.
In contrast, the problem underlying the present invention is to permit unrestricted use of the known process on synchronising components, of the type mentioned, to achieve increased precision in the formation of the coupling surfaces.
This problem is solved according to the invention by providing a process for manufacture of a finished synchronizing component for shift transmissions from a semi-finished synchronizing component, having a short toothing, formed by preliminary forging, said short toothing comprising undercut teeth, the radially inner sides of which lie against a common cylindrical surface which extends between upper and lower planar surfaces, the lower planar surface extending outwardly from a lower end of the cylindrical surface in perpendicular relation thereto, an upper end of the cylindrical surface terminating flush with the upper planar surface, said teeth of said semi-finished synchronizing component having a base portion on said lower planar surface and additionally having parallel tooth planks and a height exceeding that of the teeth of said finished synchronizing component, subjecting the tooth heads to a preliminary clenching during which material compression of the semi-finished component takes place, cold compacting the base region of the teeth on the lower planar surface to round out said teeth flanks at their bases, and subjecting the tooth heads to final clenching to impart a roof shape to the heads of said teeth and an obliqueness to the teeth flanks corresponding to their undercuts.
Essentially therefore the process of the invention entails (a) a "preliminary forging" step and (b) a "cold calibrating" step. Step (a) may entail cold or warm forging or equivalent press forming.
Step (b), entails at least one calibrating stroke and comprises a three-stage shaping process by calibrating and is in that respect fundamentally different from the mentioned prior art.
In a first stage (aa) of step (b), the tooth heads, which have been manufactured oversize in direction of the tooth length in the preliminary forging step (a), are first of all subjected to preliminary clenching; during that process the tooth flanks, which
REFERENCES:
patent: 3298219 (1967-01-01), Schober
patent: 3688549 (1972-09-01), Ohnishi et al.
Pollok Peter
Schmid Anton
Sedlmeier Andreas
Tauschek Georg
Bayerisches Leichtmetallwerk Graf Blucher von Wahlstatt GmbH
Larson Lowell A.
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