Permanent magnet polarized external rotor radial magnetic bearing

Abstract

The invention is a permanent magnet biasing inner rotor radial magnetic bearing, comprising inner magnetic conductor rings, stator iron cores, rotor iron cores, outer magnetic conductor rings, outer magnetic isolation rings, permanent magnet, excitation coils, and air gaps, where the stator iron cores I and II compose 8 magnetic poles in the positive and negative directions of X and Y axes at the left and right ends, each magnetic pole is wound with excitation coil, the inner magnetic conductor ring is inside the stator iron core, the rotor iron cores I and IV are outside the stator iron cores I and II, respectively; the rotor iron core II, the outer magnetic isolation ring, and the rotor iron core III are outside in the stator iron core III; the rotor iron cores I and II are interconnected through the outer magnetic conductor ring I; the rotor iron cores III and IV are interconnected through the outer magnetic conductor ring II; the outer magnetic conductor rings I and II are connected with the rotor iron cores II and III through the outer magnetic isolation ring, respectively; the air gaps are between the rotor iron cores and the stator iron cores; the inner magnetic conductor rings II and III are interconnected through the permanent magnet I, and the inner magnetic conductor rings III and I are interconnected through the permanent magnet II. And the invention can replace the existing magnetic bearings used in pairs, largely shortening axial distance.

Description

technical field [0001] The invention relates to a non-contact magnetic suspension bearing, in particular to a radial magnetic bearing with a permanent magnetic bias outer rotor, which can be used as a non-contact support for rotating parts in mechanical equipment such as a magnetic suspension flywheel, a magnetic suspension control moment gyroscope, a motor, and a machine tool. Background technique [0002] Magnetic suspension bearings are divided into pure electromagnetic bearings and hybrid magnetic suspension bearings with permanent magnetic bias and electromagnetic control. The former uses large current and consumes a lot of power, and the hybrid magnetic suspension bearings with permanent magnetic bias and electromagnetic control. The magnetic field generated by the permanent magnet bears the main load. Bearing capacity, the electromagnetic field provides auxiliary adjustment bearing capacity, so this kind of bearing can greatly reduce the control current and reduce the ...

AI Technical Summary

Problems solved by technology

Some of the current radial magnetic bearing structures for permanent magnet bias outer rotors are based on ordinary radial electromagnetic bearings, and permanent magnets are placed on the electromagnetic magnetic circuit, so that the magnetic flux generated by the control coil must pass through the permanent magnets. The magnetic reluctance of the magnet is very large, so the control coil needs a large excitation current to generate a certain electromagnetic flux, which will obviously increase the power consumption of the bearing; some structures directly connect the permanent magnet to the stator lamination core, so that the permanent magnet When the circuit passes through the stator core vertically, it will lose too much magnetomotive force, which will greatly weaken the attraction force of the permanent magnet to the rotor shaft; Laminated iron core forms a circuit, Chinese patent application number: 200510011270.3 and 200510011690.1 structure permanent magnet bias outer rotor radial magnetic bearing, as shown in Figure 1 and Figure 2, the permanent magnet magnetomotive force will not generate loss in the laminated iron core At the same time, the electric excitation magnetic circuit will not pass through the permanent magnet itself, but the axial length is longer due to the need to use it in pairs, so it cannot meet the small size and light weight requirements of spacecraft such as satellites and space stations.

If the excitation coils at both ends of the two magnetic bearing structures are separately controlled in order to shorten the axial length, that is, one radial magnetic bearing is used as two magnetic bearings, then the electromagnetic flux generated by the excitation coils at both ends of the magnetic bearing is in the axial direction. The direction will pass through the same electromagnetic magnetic circuit, the coupling effect is serious, which is not conducive to control; some structures such as Chinese patent application numbers: 200510086223.5, 200510086213.1 and 200510086832.0 structures of permanent magnet bias radial magnetic bearings, as shown in Figure 3, Figure 4 and Figure 5 As shown, although the permanent magnet magnetic circuit and the electric excitation magnetic circuit are in the same plane, the axial length of a single bearing can be short, but the radial magnetic bearings of these structures still need to be used in pairs when used, resulting in the overall system The axial length is still longer

And when these structures are used in pairs, they are all 16 stator core pole structures, so the weight and volume are relatively large; there are also some structures such as the permanent magnet bias radial magnetic bearing of the Chinese patent application number: 200510086831.6 structure, as shown in the figure As shown in Figure 6, the permanent magnets are embedded in two adjacent stator core poles at intervals, and the permanent magnet magnetic circuit and the electric excitation magnetic circuit are coplanar in any radial section. Although the axial dimension of a single radial magnetic bearing can be reduced, However, in actual use, they still have to be used in pairs, resulting in a large axial length and volume of the equipment, and the existence of the second air gap makes the processing process complicated

Therefore, the existing permanent magnet bias outer rotor radial magnetic bearings have the disadvantages of long axial length, large volume and heavy weight due to the need to be used in pairs

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