Bearing unit and yo-yo using the same, and ball bearing and yo-yo using the same

摘要

An object of the present invention is to provide a yo-yo with a high rotational accuracy, which can be easily and reliably centered even when disassembled and assembled by a bearing unit using a ball bearing with a simple configuration and high centering accuracy. The bearing unit 10 includes a central portion 16 having a uniform shaft diameter corresponding to the width of the inner ring 12 of the ball bearing 11, and a shaft 15 having tapered portions 17 that are tapered toward the ends on both sides. The central portion 16 of the shaft 15 is fixed to the inner ring 12.