Abstract: A worm 1 is composed of an annular tooth body 11 having a tooth 10 on the outer surface thereof, a core body 12 inserted inside the annular tooth body 11; and an elastic coupler 13, which can be transformed in the radial direction, for coupling the core body 12 with the annular tooth body 11. The worm 1 is engaged with the worm wheel with the elastic coupler 13 being transformed in the radial direction in such a manner that a negative amount of backlash is generated at the engagement portion. This can be also employed for the worm wheel. With a reduction gear combination having this structure, the backlash amount at the engagement portion can be adjusted to a proper amount without selecting elements such as the worm and the worm wheel to be assembled.

Abstract: There is provided a worm speed change apparatus comprising a worm shaft and a worm wheel meshed therewith. Rolling elements are rotatably disposed between a raceway groove formed directly in at least one of end portions of the worm shaft, and a bearing outer ring held by a housing. The worm shaft is directly supported by the rolling elements.

Abstract: A worm 1 is composed of an annular tooth body 11 having a tooth 10 on the outer surface thereof, a core body 12 inserted inside the annular tooth body 11; and an elastic coupler 13, which can be transformed in the radial direction, for coupling the core body 12 with the annular tooth body 11. The worm 1 is engaged with the worm wheel with the elastic coupler 13 being transformed in the radial direction in such a manner that a negative amount of backlash is generated at the engagement portion. This can be also employed for the worm wheel. With a reduction gear combination having this structure, the backlash amount at the engagement portion can be adjusted to a proper amount without selecting elements such as the worm and the worm wheel to be assembled.

Abstract: A steering locking device has an annular clearance provided between a steering shaft and a collar surrounding the steering shaft. A spacer is press-fitted in the annular clearance, to form a circular arc shape surrounding the steering shaft. The spacer is wound around the steering shaft from the outside of the collar through the opening of the collar. When a locking member supported on a locking device main body is at a locked position, the collar is prevented from being rotated. When a torque applied to the steering shaft is not more than a predetermined torque, the spacer prevents the relative rotation between the steering shaft and the collar.

Abstract: There is provided a worm speed change apparatus comprising a worm shaft and a worm wheel meshed therewith. Rolling elements are rotatably disposed between a raceway groove formed directly in at least one of end portions of the worm shaft, and a bearing outer ring held by a housing. The worm shaft is directly supported by the rolling elements.

Abstract: A steering locking device has an annular clearance provided between a steering shaft and a collar surrounding the steering shaft. A spacer is press-fitted in the annular clearance, to form a circular arc shape surrounding the steering shaft. The spacer is wound around the steering shaft from the outside of the collar through the opening of the collar.