| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration of bearing performance and to reduce rotation slip of a ball caused by fluctuation of position of a contact point of a raceway surface and the ball caused by machining error of the raceway surface. SOLUTION: In a four contact point ball bearing, each of four annular raceway surfaces 6, 7, 8, 9 dividing and forming an annular raceway 4 is regulated by a concave surface having a curvature radius largest at a contact point 22 where the ball contacts and gradually reduced as it separates from the contact point 22 in a surface shape cut with a plane including a rotational axis 1a thereof. Fluctuation of position of the contact point of the raceway surface and the ball due to machining error can be controlled and ball rotation slip can be reduced thereby. Since contact surface of each raceway surface and balls can be reduced, differential slip between each raceway surface and the ball can be reduced. |
