steering system has cremaillere

This invention relates to a rack and pinion steering system adapted to effectively reduce a return force whilst ensuring a high degree of freedom. The sum angle of inclination of the rack tooth with respect to a reference line perpendicular to the axis of the rack and the angle of inclination of a sprocket tooth with respect to the axis of the pinion shaft does not coincide with the angle of inclination of the axis of the pinion shaft with respect to the reference line. A bulge is provided on the surface of the rack tooth (or sprocket) so as to decrease the tooth width on one end side in the direction of tooth trace and increase the tooth width on the the other end side according to the state of contact with the sprocket (or rack tooth) opposite.