Worm gear mechanism and electric power steering apparatus equipped therewith

摘要

Worm gear mechanism includes a driving worm, a torque delivering worm wheel meshing with the worm, and an auxiliary worm wheel superimposed on the torque delivering worm wheel. The auxiliary worm wheel has a pitch diameter greater than that of the torque delivering worm wheel. The auxiliary worm wheel is biased against the driving worm wheel via a biasing member in the form of a leaf spring.