Application of flow forming process to automatic transmission parts

摘要

Net shape forming is regarded as one of effective methods for cost reduction by means of process curtailment or productivity improvement, in addition to material saving. Moreover, one piece forming is most effective in case it is applied to the parts manufactured by welding several parts. On the other hand, automatic transmission parts are the typical complex parts, which have several portions of different thickness or multi-cylindrical shape. Therefore, new process development has been required to realize low cost manufacturing. In this respect, we have developed flow-forming process to produce the forward clutch hub in one-piece and net-shaping from steel tube material, and have applied this new process to AT. Conventionally, we had to manufacture this kind of parts by welding two parts produced by forging, machining, heat treatment, stamping or etc. Owing to the developed new process, we could eliminate beat treatment, welding and its peripheral processes, and lubrication for stamping as well, which results in the whole process reduction to one third. This paper introduces outline of the new process development and establishment of quality control in series production.