The trial forming of a spur gear made from the drawn cup by plastic working

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In previous report, it was proposed that a new production method in which a spur gear was made from the drawn cup by plastic working. This forming method consists of four processes, namely drawing, re-striking, ironing and compressing process. However, the forming of steel gears isn't suitable for the actual production because the forming pressure in the compressing process is too high. And, filling ratio is not also enough. So, It is examined to reduce forming pressure and to improve filling ratio by two types of the divided flow forging method. One is how to flow material into the opposite side of tooth by using the cushion punch with grooves. The other is how to flow material into the clearance between the cushion punch and compressing plate which enlarged the bore. It is found that divided flow methods be able to improve of filling ratio and to reduce of forming pressure. Test materials are aluminum (A1050) and mild steel (SPHC). The FEM simulation was done by using deform3D-v3.3. A deformation mechanism by the FEM simulation is very similar to the experimental result, and it can estimate state of filling up in the tooth top and forming pressure. As a result, when a divided flow punch was used, the decrease rate of the forming pressure was 22.6%, and when the divided flow plate was used, the decrease rate of the forming pressure was 14.3%. It was found that divided flow method could improve of filling ratio and decrease of forming pressure and the effect of it wasn't based on materials. A deformation mechanism by the FEM simulation was very similar to the experiment result, and it was found that it could guess filling up of the tooth top and forming pressure.