In order to solve a problem of an electric power steering device of an
automobile that the steering feeling is deteriorated by dragging the
inactive electric motor if a steering member is operated at a small angle
to leave an electric motor inactive while the automobile is running
straight, the present invention provides a joint for jointing the rotary
shaft of a steering assisting electric motor and a worm shaft of a
reduction mechanism, comprising a first member rotating integrally with
the rotary shaft; a second member rotating integrally with the worm
shaft; and an elastic member for coupling the two members in a torque
transmittable manner. The elastic member has a relatively small elastic
modulus according to the state that the torsion angle between the first
and second members is small. Accordingly, the structure and
characteristics thereof lead to a better operationality of the steering
member.