Abstract: A motor is attached to an outer column which is mounted on a vehicle body. A driving force of the motor is transmitted to an inner column by a driving member via a screw shaft. The driving member includes a first protrusion engaged in and fixed to an engaging hole of the inner column and a second protrusion inserted into a long hole of the inner column. The first protrusion is pressed against the engaging hole and sheared when the inner column receives an impact load toward a vehicle body forward direction. The second protrusion relatively moves in the long hole while receiving sliding frictional resistance toward a vehicle body rearward direction and being elastically deformed when the inner column receives the impact load toward the vehicle body forward direction.

Abstract: A first reduction ratio established between first internal teeth of an input gear and first external teeth of a first planetary gear of an annular planetary gear unit is set different from a second reduction ratio established between a second internal teeth of an output gear and second external teeth of a second planetary gear of the annular planetary gear unit. A rotation cam unit is installed in a circular opening of the annular planetary gear unit to cause, upon rotation thereof, the first and second planetary gears to make an eccentric rotation relative to a common axis of the first and second internal teeth thereby to induce a circumferential movement of a first meshed portion between the first external teeth and the first internal teeth and a second meshed portion between the second external teeth and the second internal teeth. The rotation cam unit is actuated by an electric motor.

Abstract: In a steer-by-wire vehicle steering system configured to execute a direct-coupled mode via a clutch for failsafe, the clutch includes a first member fixed to a clutch output shaft, a second member defining a cylindrical outer peripheral wall surface in rolling-contact with a cylindrical inner peripheral wall surface of the first member, and a pair of spring-loaded wedges movably interposed between the two members. Also provided is a lock pin, which squeezes into and retreats out of a space defined between the two opposing first wedge ends to ensure a lock state, namely, the engaged state with the jammed wedges and an unlock state, namely, the disengaged state with the unjammed wedges. A steering-movement transmission member, fixed to a clutch input shaft, is interleaved between the circumferentially-spaced second wedge ends to keep the two opposing first wedge ends in close proximity to each other.