Bearing with projections projected in radial direction from outer surface and from an inner surface thereof and image forming apparatus

A bearing for supporting a rotation shaft configured to rotate a rotatable member, said bearing being capable of being supported by a supporting portion provided with an engaging hole engageable with said bearing, said bearing comprising:

• a plurality of positioning projections configured to determine a position of said bearing in the engaging hole with respect to a radial direction of said rotation shaft by engaging said bearing with the engaging hole, wherein said positioning projections project in the radial direction from an outer surface of said bearing opposing an inner wall surface of the engaging hole so as to be away from a rotation center of said rotation shaft and include outer peripheral contact surfaces contacting the inner wall surface of the engaging hole, and
• a plurality of bearing projections configured to bear said rotation shaft, wherein said bearing projections project in the radial direction from an inner surface of said bearing opposing an outer peripheral surface of said rotation shaft toward the rotation center and include inner peripheral sliding surfaces on which the outer peripheral surface of said rotation shaft slides,
• wherein said positioning projections project from different positions with respect to a circumferential direction of said rotation shaft so that between adjacent positioning projections with respect to the circumferential direction, the outer peripheral surface of said bearing and the inner wall surface of the engaging hole form a gap therebetween,
• wherein said bearing projections project from different positions with respect to the circumferential direction so that between adjacent bearing projections, the inner peripheral surface of said bearing and the outer peripheral surface of said rotation shaft form a gap therebetween, and
• wherein with respect to the circumferential direction of said rotation shaft, said positioning projections and said bearing projections are provided at positions different from each other.