WORM WHEEL AND ELECTRIC POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To enhance bonding strength between a cored bar and a rim portion of a worm wheel in which an outer peripheral portion of the metallic cored bar is covered with the synthetic resin rim portion, compared to conventional products.SOLUTION: A cored bar 1A of a worm wheel includes: one end surface in the axial direction having a first annular recessed portion 12 formed thereon; the other end surface in the axial direction having a second annular recessed portion 13 formed thereon; and a third recessed portion 14 formed in the radial outer region of the first annular recessed portion 12. A rim portion 2A includes: a first inner peripheral portion 22 fixed to the first annular recessed portion 12; a second inner peripheral portion 23 fixed to the second annular recessed portion 13; and a projecting portion 24 fitted to the third annular recessed portion 14. An inner peripheral side wall surface 13e of the second annular recessed portion 13 extends from a bottom surface 13d of the second annular recessed portion 13 in a tapered manner to form an obtuse angle to the bottom surface 13d.