Telescopic structure and steering column device for motor vehicle

An automotive steering column apparatus comprising:

• an inner column rotatably supporting a steering shaft;
• an outer column holding the inner column while rotatably embracing the inner column;
• a vehicle body side bracket having a vehicle body mount portion which can be mounted on a vehicle body and a pair of left and right facing flat plate portions which extend substantially vertically on opposite sides of the outer column, respectively;
• a clamping mechanism for changing a width of the pair of facing flat plate portions and changing a width of an inner circumferential surface of the outer column in connection with a change in the width of the pair of facing flat portions;
• and
• a shear ring mounted on at least either the inner circumferential surface of the outer column or an outer circumferential surface of the inner column, the shearing ring comprising a metallic ring and a resin ring made of synthetic resin,
• wherein the metallic ring fits on one of an outer circumferential side and an inner circumferential side of the resin ring,
• wherein a shear permissive projection is provided on the shear ring,
• wherein a groove is formed in at least either the inner circumferential surface of the outer column or the outer circumferential surface of the inner column, and
• wherein the shear permissive projection is in engagement with the groove.