| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a gear forming device capable of improving the formation accuracy of a helical gear, and also of improving the durability of a die. <P>SOLUTION: There is provided a gear forming device for forming a helical gear having the spiral external teeth on an outer periphery by applying an enclosed die cold forging process to a raw material. In a forging space formed by abuting a punch against the periphery of the upper opening 211 of a die-forming hole 21 and engaging the outer peripheral teeth of a sleeve with the inner peripheral teeth 22 of the die, a helical gear is formed by pressurizing the raw material with the punch and die sleeve to fluidize a part of the raw material to the inner peripheral teeth 22. In an axial upper end 230 in the teeth mountain part 23 of the inner peripheral teeth 22, the corner part 24 of the acute angle side positioning at one side 231 in the peripheral direction in the axial upper end 230 is cut viewing the upper end 230 from a radial inner peripheral side. <P>COPYRIGHT: (C)2012,JPO&INPIT |
