To realize a compact structure providing superior responsiveness and heightening energy efficiency of an electric motor.
An auxiliary rotary shaft 29 and an idler shaft 50, and a main rotary shaft 23 rotating based on operation of a steering wheel, are arranged in a state wherein each center axes α and β intersect. Both a driving frictional surface 38 of a driving disc 37 fixed concentrically with the auxiliary rotary shaft 29 and a driving side idler frictional surface 56 of a driving side idler disc 55 arranged concentrically with the idler shaft 50 are frictionally engaged to both a driven frictional surface 45 of a driven disc 43 supported concentrically with the main rotary shaft 23 and a driven side idler frictional surface 47 of a driven side idler disc 44. Abutting pressure between each surfaces are secured by coned disc springs 36 and 54. A ratio of the driving frictional surface 38 diameter and the driven frictional surface 45 diameter is increased for increasing a reduction ratio of a reduction gear 28.
OTAKI RYOICHI
NISHIMURA NOBUYUKI
