| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball bearing capable of preventing catch by non-woven fabric etc., when the ball bearing is disassembled or assembled even when a recessed surface is formed on an outer peripheral surface of an outer wheel, and improving workability by suppressing sharp impressions, and excess consideration of safety, and a yo-yo using the same.SOLUTION: A ball bearing 61 has: an inner wheel 62 and an outer wheel 63 made of martensitic stainless steel; and a ball 64 which is disposed between the inner wheel 62 and the outer wheel 63. A recessed surface 71 to be line symmetry in an axial direction regarding a position of the ball 64 is formed on an outer peripheral surface of the outer wheel 63, an outer diameter of the recessed surface 71 is the smallest at a position of a center part in the axial direction where the ball 64 is disposed, flat surfaces 72 to be perpendicular to an end surface of the outer wheel 63 are formed, respectively, on both sides in the axial direction of the recessed surface 71, width dimensions of the flat surfaces 72 are set as 0.06 mm or more, the ball bearing 61 is recognized as an obtuse angle to a finger on the end surface of the outer wheel 63, and a sharp feeling is not given even when it contacts the finger. |
