| 摘要 |
An electric power steering apparatus includes a worm wheel (8) having an annular tooth portion (8) made of synthetic resin and a boss portion (82) made of metal. The annular tooth portion (81) has teeth that engage with a worm (7), and the boss portion (82) is fitted to the annular tooth portion (81). One of an inside peripheral surface of the annular tooth portion (81) and an outside peripheral surface of the boss portion (82) has concaves disposed on both axial ends thereof, and the other has convexes fitted into the concaves. The radial length of these concaves and convexes is 1 to 2.5 times as large as the axial length of the concaves and convexes. <IMAGE> |
