As the energy densities in permanent magnet materials increases, permanent magnet (PM) bearings are becoming increasingly attractive machine elements for applications ranging from turbo machinery to energy storage flywheels. Desirable qualities include high speed, low wear, energy savings, and freedom from lubricants that can degrade or contaminate other system components. In this paper we develop analytical expressions for stiffness and peak load in stacked-structure radial magnetic bearings that extend the seminal work of Backers, and Yonnet and co-workers. In addition to the derivation of simple design rules, the axial peak force and negative axial stiffness are calculated.

1.
Yonnet
,
J. P.
,
Lemarquand
,
G.
,
Hemmerlin
,
S.
, and
Olvierrulliere
,
E.
,
1991
, “
Stacked Structures of Passive Magnetic Bearings
,”
J. Appl. Phys.
,
70
(
10
), pp.
6633
6635
.
2.
Antaki
,
J.
,
Banda
,
S.
,
Paden
,
B.
, and
Piovoso
,
M.
,
2002
, “
Award Winning Control Applications
,”
IEEE Control Syst. Mag.
,
22
(
6
), December, pp.
8
20
.
3.
Baermann, M., 1956, German patent application B 30 042 dated 1954 (German specification 1071 871).
4.
Backers
,
F. T.
,
1960
–1961, “
A Magnetic Journal Bearing
,”
Philips Tech. Rev.
,
22
, pp.
232
238
.
5.
Yonnet
,
J. P.
,
1978
, “
Passive Magnetic Bearings With Permanent Magnets
,”
IEEE Trans. Magn.
,
14
(
5
), pp.
803
805
.
6.
Yonnet
,
J. P.
,
1981
, “
Permanent Magnet Bearings and Couplings
,”
IEEE Trans. Magn.
,
17
(
1
), pp.
1169
1173
.
7.
Marinescu
,
M.
, and
Marinescu
,
N.
,
1994
, “
A New Improved Method for Computation of Radial Stiffness in Permanent Magnet Bearings
,”
IEEE Trans. Magn.
,
30
(
5
), pp.
3491
3494
.
8.
Abramowitz, M., and Stegun, I. A., eds., 1964, Handbook of Mathematical Functions, Washington, DC; National Bureau of Standards.
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