| 摘要 |
PURPOSE:To obtain the excellent dimension accuracy, and to improve the productivity by specifying a ratio of the diameter of a root circle of a gear part to the diameter of a shaft part, and providing a hollow part inside of a shaft- integrated gear. CONSTITUTION:In a shaft-integrated gear to be used for a wide range as a mechanical part in each field of precision machine, electricity, electron or the like, a ratio of the diameter of a root circle of a gear part 2 to the diameter of a shaft part 1 is set at 1/1-5/1. This molding has a hollow part, and a hollow ratio is set in a range of 5-70%. Since this gear does not have a joint part and it can be molded by the injection at one time and a burr is hardly generated, it is molded by the hollow injection molding that gas is filled in a resin after injecting the thermoplastic resin into a mold cavity. As thermoplastic resin, polyacetal resin and polyamide resin are used. |
