Patent ID: 8824105

Claim:
A pivot bearing ( 13 ) which is disposed in a fixing hole ( 18 ) of an arm ( 16 ) via a tolerance ring ( 12 ), comprising: a shaft ( 21 ); and a plurality of ball bearings ( 20 ) arranged in an axial direction with respect to the shaft, each of the ball bearings ( 20 ) comprising: an inner ring ( 27 ) fixed to the shaft ( 21 ), the inner ring ( 27 ) having a raceway groove; an outer ring ( 25 ) fixed to the arm ( 16 ) via the tolerance ring ( 12 ), the outer ring ( 25 ) having a raceway groove opposed to the raceway groove of the inner ring ( 27 ); and a plurality of balls ( 26 ) provided between the raceway groove of the inner ring ( 27 ) and the raceway groove of the outer ring ( 25 ), wherein, with respect to each of the ball bearings, the number of balls ( 26 ) and the number of concave portions ( 12 b ) of the tolerance ring ( 12 ), which are configured to directly press the outer ring ( 25 ), are relatively prime to each other.