An electric power steering system is provided, which comprises a steering assist
electric motor, and a reduction gear mechanism for reducing a rotation speed of
a rotatable shaft of the electric motor. The reduction gear mechanism comprises
a worm shaft driven by the rotatable shaft, and a worm wheel driven by the warm
shaft. The electric power steering system further comprises a joint for coupling
the rotatable shaft to the worm shaft for transmission of a driving force. Longitudinally
biasing means is provided in association with the joint for longitudinally biasing
the worm shaft.
