| 摘要 |
PROBLEM TO BE SOLVED: To increase the rotation torque strength between a gear and a wheel gear fixed thereto, to reduce dimension of the wheel gear, and to lower the cost while restricting the quantity of the resin material in the gear having the resin wheel gear integrally fixed to a metal rotary shaft thereof. SOLUTION: One end of a rotary shaft 14 of a gear is provided with a gear fixing part 20. The gear fixing part 20 has a projecting part 22 formed with plural projections 24 in the peripheral surface thereof and a flange part 26. These projecting part 22 and the flange part 26 are formed by the cold forging while being plastically deformed, and a boss part of a wheel gear is integrally fixed to the periphery of the gear fixing part 20. Since depth of the projections 24 can freely be set independently of the number of projections and the length of the circumference, rotation torque strength between the rotary shaft 14 and the wheel gear can be increased. |
