| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a caster for rotating a wheel frame with respect to an installation board which can be easily manufactured, can be assembled with high accuracy and the cost required for the same can be reduced.SOLUTION: A caster has an installation board 2, a wheel frame 3 and a wheel 4. The installation board 2 is provided with a projecting cylindrical boss 10 which externally fits to and holds a bearing 5 for rotation, the wheel frame 3 is provided with a housing part 17 which internally fits and holds a periphery of the bearing 5, and a joint bolt 7 for joining the installation board 2 with the wheel frame 3 can be inserted into a hollow part 12 of the cylindrical boss 10. The cylindrical boss 10 is formed by a non-hardening raw material, and the joint bolt 7 is formed by a hardening raw material. An outer diameter of a shank of the joint bolt 7 and an inner diameter of the hollow part 12 of the cylindrical boss 10 are made to be a fit tolerance of a tight fit, whereby an outer circumferential surface of the cylindrical boss 10 is brought into pressure contact with an inner circumferential surface of the bearing 5 by press fitting of the joint bolt 7.</p> |
