Lévitation Forces in a Superconducting Linear Bearing

Abstract

A prototype of a superconducting linear bearing has been successfully developed. The superconducting linear bearing consists of a high-T_c superconductor shaft (type-II superconductor) and a cylindrical housing of alternating-polarity bar magnets of the same size. By using the alternating-polarity magnets the superconductor shaft can be levitated in the center of the housing with no contacts. Levitation properties of the superconducting linear bearing are investigated. The levitation force shows circular hysteresis loops depending on the displacement amplitude because of the flux pinning effect. The circular hysteresis loops of the levitation force are explained by using simple mechanisms for the superconducting linear bearing. Due to the simple structure of the superconducting linear bearing it is applicable to practical apparatuses in industrial fields.

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References

Hellman

, Gyorgy

E.M.

, Johnson

D.W.

Jr. , O'Bryan

H.M.

and Sherwood

R.C.

, Levitation of a magnet over a flat type II superconductor, J. Appl. Phys. 63 (1988) 447–450.

Brandt

E.H.

, Friction in levitated superconductors, Appl. Phys. Lett. 53 (1988) 1554–1556.

Moon

F.C.

, Yanoviak

M.M.

and Ware

, Hysteretic levitation forces in superconducting ceramics, Appl. Phys. Lett. 52 (1988) 1534–1536.

Moon

F.C.

, Weng

K.-C.

and Chang

P.-Z.

, Dynamic magnetic forces in superconducting ceramics, J. Appl. Phys. 66 (1989) 5643–5645.

Moon

F.C.

and Chang

P.-Z.

, High-speed rotation of magnets on high T_c superconducting bearings, Appl. Phys. Lett. 56 (1990) 397–399.

Chang

P.-Z.

, Moon

F.C.

, Hull

J.R.

and Mulcahy

T.M.

, Levitation force and magnetic stiffness in bulk high-temperature superconductors, J. Appl. Phys. 67 (1990) 4358–4360.

Murakami

, Oyama

, Fujimoto

, Taguchi

, Gotoh

, Shiohara

, Kosizuka

and Tanaka

, Large levitation force due to flux pinning in YBaCuO superconductors fabricated by melt-powder-melt growth process, Jpn. J. Appl. Phys. 29 (1990) L1991–L1994.

Kim

, Katsurai

and Fujita

, Fabrication and testing of a micro superconducting actuator using the Meissner effect, IEEE Workshop on Micro Electro Mechanical Systems (Napa Valley, California, 1990) pp. 61–66.

Komori

and Kitamura

, Fuzzy control of a superconductive linear slider, Int. Conf. on Fuzzy Logic & Neural Networks (Iizuka, Japan, 1990) pp. 87–90.

10.

Komori

and Kitamura

, Development of a superconductive levitational mechanism and its application to a superconductive radial bearing, Cryog. Eng. 25 (1990) 411–413.

11.

Kitamura

and Komori

, Levitational bearing systems by Meissner effect, Micro System Technology ‘90 (Berlin, 1990) pp. 826–831.

12.

Komori

and Kitamura

, Static levitation in a high-T_c superconductor tile on magnet arrangements, J. Appl. Phys. 69 (1991) 7306–7309.

13.

Komori

and Kitamura

, Drag pressures of a set of alternating-polarity magnets over a superconductor tile, J. Appl. Phys. 70 (1991) 2226–2229.