| 摘要 |
PROBLEM TO BE SOLVED: To increase a wear resisting strength and resistance to burning in the track surface of a touchdown bearing by making the turning wheel of a touchdown rolling bearing with steel and a rolling element with ceramic in a magnetic bearing device where a rotor is supported by the touchdown rolling bearing when power is cut off. SOLUTION: A rotor 3 having a disk part 5 provided in the thin shaft 4 of its lower end part is housed in a cylindrical case 2 with a bottom, the upper part of the rotor 3 is supported by a magnetic bearing 6 and the disk part 5 of the lower side of the rotor 3 is supported by magnetic bearings 7 and 8. A deep groove ball bearing 12 as a touchdown bearing is attached and fixed in a peripheral recessed groove 11 formed in the end part 10a of a flange 10 formed in a radial direction from the upper case inner wall 2a of the magnetic bearing 6. This touchdown bearing 12 is composed of inner and outer rings made of bearing steels as materials and a rolling element, and TiN layer thin film layers are formed by coating on the inner peripheral surface of the inner ring used as a turning wheel at the time of touching down, the track surface of the same and the track surface of the outer ring. |
