| 摘要 |
PURPOSE:To manufacture tooth form simply and to finish it efficiently and precisely by dividing a circular mold material into a plurality of segmental molds. CONSTITUTION:A mold material is divided radially into four segments and the inner circumferential surface of each segmental mold 2 is ground by a gear- tooth forming grinder 3 to provide a tooth form 6 consisting of a crest part 4 and a trough part 5. Grinding is carried out so that the crest parts 4, 4 or a trough part 7a of a plastic gear 7 are positioned on segmental surfaces 2a, 2a of segmental molds 2... and pins 8, 8 are plunged into the mold surface of each segmental mold 2. The segmental molds 2... are assembled in a circular form, mounted on the end of the mold body 9 and fixed with the pins 8, 8, then a mold 11 having a gear type cavity 10 is obtained. In this case, the tooth form is always made constant on the crest part 7b of the plastic gear 7 and the joining parts of the segmental molds 2 do not exert any adverse effect on the profile and the surface roughness of the crest part 7b of the plastic gear 7. |
