| 摘要 |
PROBLEM TO BE SOLVED: To provide a forming die by which an outer helical gear excellent in the precision of a tooth profile can be stably formed. SOLUTION: In a die 2 equipping with a tooth profile forming part 7 constituted by providing lands 5 for tooth profile forming and land relief 6 successively, which relieves the lands 5 in the outside direction of a radius, a side surface land part 5c inclined upward to the stock push-in direction is extended in the extruding direction of a material inclined in the axial direction. By fluidizing the material which has passed through the lands 5 along this extended part 10, by controlling the spring back of the material, and especially by preventing the deformations of tooth traces on both sides of the tooth profile, the precision of the tooth profile is improved.
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