Bearing and steering mechanism

A bearing comprising:

• a bush body with a central longitudinal axis, the bush body comprising:
• a mounting groove formed in an outer peripheral surface of the bush body and extending in a circumferential direction of the bush body, the mounting groove having a large-diameter part and a small-diameter part, a groove bottom of the mounting groove in the large-diameter part having a first radius of curvature originating at the central longitudinal axis of the bush body, the groove bottom of the mounting groove in the small-diameter part having a second radius of curvature originating at the central longitudinal axis of the bush body, the second radius of curvature being smaller than the first radius of curvature, the mounting groove being deeper in the small-diameter part than in the large-diameter part,
• slits formed from one end surface toward another end surface of the bush body and thereby allowing the bush body to be freely expanded and contracted in a radial direction of the bush body, the slits all being arranged to intersect the small-diameter part of the mounting groove;
• and
• an elastic ring mounted in the mounting groove of the bush body.