CN112879431A

CN112879431A - Magnetic suspension bearing, bearing system and motor

Info

Publication number: CN112879431A
Application number: CN202110198364.5A
Authority: CN
Inventors: 曹俊辉; 伍尚权; 林学明; 王周叶
Original assignee: Gree Electric Appliances Inc of Zhuhai; Zhuhai Kaibang Motor Manufacture Co Ltd
Current assignee: Gree Electric Appliances Inc of Zhuhai; Zhuhai Kaibang Motor Manufacture Co Ltd
Priority date: 2021-02-22
Filing date: 2021-02-22
Publication date: 2021-06-01

Abstract

The present disclosure provides a magnetic suspension bearing, a bearing system and a motor, the magnetic suspension bearing includes: the stator component is provided with a radial control coil and an axial control coil; the thrust assembly is assembled on the rotating shaft and comprises a first thrust disc and a second thrust disc, and the first thrust disc and the second thrust disc are symmetrically arranged at two axial ends of the stator assembly; the stator assembly is configured to provide three degrees of freedom of levitation support for the rotating shaft through the thrust assembly. The magnetic suspension bearing disclosed by the invention realizes three-degree-of-freedom support of the rotating shaft, independently controls the radial magnetic suspension load and the axial magnetic suspension load, reduces the number of bearing assemblies into two, and reduces the axial length of the rotating shaft; the thrust disc is matched with the rotating shaft in a symmetrical hot sleeve mode, the magnetic paths of the magnetic suspension bearing are symmetrical theoretically, magnetic leakage of the magnetic suspension bearing is reduced, stable and symmetrical suspension support is provided for the rotating shaft, and load control difficulty of axial magnetic suspension and radial magnetic suspension is reduced.

Description

Magnetic suspension bearing, bearing system and motor

Technical Field

The disclosure belongs to the technical field of magnetic suspension bearings, and particularly relates to a magnetic suspension bearing, a bearing system and a motor.

Background

The magnetic suspension motor suspends the motor rotor in the air by utilizing the electromagnetic force action of the magnetic suspension bearing, so that the motor rotor is not in mechanical contact with the motor stator, mechanical friction is avoided, and the magnetic suspension motor has the characteristics of low loss and high performance. Meanwhile, the oil-free oil-saving pump has the advantages of low noise, long service life, no need of lubrication and sealing, no oil pollution and the like. The rotating speed of the motor rotor is only limited by the tensile strength of the rotor material, so the peripheral speed of the magnetic suspension motor rotor can be very high, and the application in high-speed equipment is more and more extensive. Magnetic suspension bearings in the related art can only provide single axial or radial support, the active magnetic suspension bearing system and the hybrid magnetic suspension bearing generally adopt two radial bearings and one axial bearing to control 5 degrees of freedom of a rotating shaft, so that a rotor can be stably suspended, the three bearings occupy large space, the axial distance of the rotor is large, and the radial fluctuation of the rotor during working is large, thereby increasing the bearing control difficulty.

Disclosure of Invention

Therefore, the technical problem to be solved by the present disclosure is that a magnetic suspension bearing can only provide a single axial or radial support, two radial bearings and one axial bearing are required to control a rotating shaft, the occupied space is large, and the working performance of a rotor is affected, thereby providing a magnetic suspension bearing, a bearing system and a motor.

In order to solve the above problem, the present disclosure provides a magnetic suspension bearing, including:

the stator assembly is provided with a radial control coil and an axial control coil;

the thrust assembly is assembled on the rotating shaft and comprises a first thrust disc and a second thrust disc, and the first thrust disc and the second thrust disc are symmetrically arranged at two axial ends of the stator assembly;

the stator assembly is configured to provide three degrees of freedom of levitation support for the rotating shaft through the thrust assembly.

The purpose of the present disclosure and the technical problems solved thereby can be further achieved by the following technical measures.

In some embodiments, the stator assembly includes an outer bearing core, an inner bearing core disposed within the outer bearing core.

In some embodiments, the axial end faces of the first thrust plate and the second thrust plate, which are opposite to each other, are thrust faces, a first stepped portion and a second stepped portion are arranged on each thrust face, the first stepped portion and the outer bearing core are arranged correspondingly in the axial direction of the stator assembly, and the second stepped portion and the inner bearing core are arranged correspondingly in the axial direction of the stator assembly.

In some embodiments, the thrust surface is further provided with a third stepped portion, the thrust assembly further comprises a rotor core, the rotor core and the third stepped portion are arranged correspondingly in the axial direction of the stator assembly, the first thrust disk, the rotor core and the second thrust disk are assembled on the rotating shaft in a shrinkage fit mode, and the rotor core is compressed between the first thrust disk and the second thrust disk.

In some embodiments, the first step portion, the second step portion and the third step portion are sequentially and concentrically arranged from the edge of the thrust surface to the center of the thrust surface.

In some embodiments, a permanent magnet ring is disposed between the inner bearing core and the outer bearing core, and the permanent magnet ring is magnetized in a radial direction.

In some embodiments, the outer bearing core includes a sleeve portion and a flange portion, the outer bearing core is mounted by the fixing flange portion, the permanent magnet ring is assembled in the sleeve portion, and a first positioning ring and a second positioning ring are respectively disposed at two ends of the permanent magnet ring and tightly fix the permanent magnet ring in the sleeve portion.

In some embodiments, the thickness of the first positioning ring and the second positioning ring along the radial direction of the stator assembly is larger than that of the permanent magnet ring along the radial direction of the stator assembly, and the first positioning ring and the second positioning ring can tightly press and fix the edge of the inner bearing iron core.

In some embodiments, an annular boss is provided on the inner wall of the sleeve portion, and the permanent magnet ring is fitted on the annular boss, and the axial length of the annular boss along the stator assembly is the same as the axial length of the permanent magnet ring along the stator assembly.

In some embodiments, an axial gap between the first positioning ring and the first thrust disk is smaller than an axial gap between the outer bearing core and the first thrust disk, and an axial gap between the second positioning ring and the second thrust disk is smaller than an axial gap between the outer bearing core and the second thrust disk; and/or the first positioning ring and the second positioning ring are made of aluminum materials.

In some embodiments, the outer bearing core includes a first core body and a second core body that are symmetrically disposed.

In some embodiments, the inner bearing core is provided with a shaft hole, the inner wall of the shaft hole is provided with a wire groove, and the radial control coil is wound in the wire groove.

In some embodiments, the wireway is a trapezoidal slot.

In some embodiments, a first coil bobbin and a second coil bobbin are respectively disposed on two axial end faces of the inner bearing core, the axial control coil includes a first axial coil and a second axial coil, the first axial coil is wound in the first coil bobbin, and the second axial coil is wound in the second coil bobbin.

In some embodiments, the first coil bobbin and the second coil bobbin are respectively installed in the installation holes of the inner bearing core through the installation posts, and the installation holes are uniformly arranged along the circumferential direction of the inner bearing core.

A bearing system comprises the magnetic suspension bearing.

A motor comprises the magnetic suspension bearing.

In some embodiments, the motor further includes a housing, and when the outer bearing core is included and the flange portion is provided on the outer bearing core, the flange portion of the outer bearing core is fixedly assembled on the housing.

The magnetic suspension bearing, the bearing system and the motor provided by the disclosure have the following beneficial effects:

the magnetic suspension bearing can realize three-degree-of-freedom support of the rotating shaft, and independent control of radial magnetic suspension load and axial magnetic suspension load, can reduce three bearing assemblies in the related technology into two bearing assemblies, reduces the volume by nearly one half, greatly reduces the axial length of the rotating shaft, improves the fixed frequency and the rigidity of the rotating shaft, and improves the critical rotating speed of the rotating shaft; simultaneously, the double thrust plates are symmetrical, the thermal sleeve is matched on the rotating shaft, the magnetic paths of the magnetic suspension bearing are symmetrical on the basis of the magnetic path theory, the magnetic leakage of the magnetic suspension bearing can be greatly reduced, and when the rotating shaft moves axially, the double thrust plates provide stable and symmetrical suspension support for the rotating shaft under the action of the axial magnetic force provided by the axial control coil, so that the load control difficulty of axial and radial magnetic suspension is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a magnetic bearing according to an embodiment of the present disclosure;

fig. 2 is an exploded view of a component of a stator assembly of an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a first thrust plate of an embodiment of the present disclosure;

fig. 4 is a schematic structural view of a second core body according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural view of an inner bearing core according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of an electric machine according to an embodiment of the present disclosure;

FIG. 7 is a schematic axial magnetic circuit diagram of a magnetic suspension bearing according to an embodiment of the present disclosure;

fig. 8 is a schematic view of a radial magnetic circuit of a magnetic suspension bearing according to an embodiment of the present disclosure.

The reference numerals are represented as:

1. a stator assembly; 2. a radial control coil; 3. an axial control coil; 4. a thrust assembly; 5. a rotating shaft; 6. a first thrust plate; 7. a second thrust plate; 8. an outer bearing core; 9. an inner bearing core; 10. a thrust surface; 11. a first step portion; 12. a second step portion; 13. a third step portion; 14. a rotor core; 15. a permanent magnet ring; 16. a sleeve portion; 17. a flange portion; 18. a first positioning ring; 19. a second positioning ring; 20. an annular boss; 21. a first core body; 22. a second core body; 23. a shaft hole; 24. a wire slot; 25. a first coil bobbin; 26. a second coil bobbin; 27. a first axial coil; 28. a second axial coil; 29. mounting a column; 30. mounting holes; 31. a housing; 32. a magnetic suspension bearing; 33. a screw; 34. and (7) fixing holes.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, the following embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings. It is to be understood that the described embodiments are merely a subset of the disclosed embodiments and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.

As shown in fig. 1 to 8, the present disclosure provides a magnetic suspension bearing 32, including: the stator assembly 1 is provided with a radial control coil 2 and an axial control coil 3; the thrust assembly 4 is assembled on the rotating shaft 5, the thrust assembly 4 comprises a first thrust disk 6 and a second thrust disk 7, and the first thrust disk 6 and the second thrust disk 7 are symmetrically arranged at two axial ends of the stator assembly 1; the stator assembly 1 is configured to provide three degrees of freedom of levitation support for the rotating shaft 5 through the thrust assembly 4.

The magnetic suspension bearing 32 disclosed by the invention can realize three-degree-of-freedom support of the rotating shaft 5, and independent control of radial magnetic suspension load and axial magnetic suspension load, can reduce three bearing assemblies in the related technology into two bearing assemblies, and reduce the volume by nearly one half, thereby greatly reducing the axial length of the rotating shaft 5, improving the fixed frequency and rigidity of the rotating shaft 5, and improving the critical rotating speed of the rotating shaft 5; meanwhile, the double thrust plates are symmetrical, the thermal sleeve is matched on the rotating shaft 5, the magnetic paths of the magnetic suspension bearing are symmetrical theoretically on the magnetic paths, the magnetic leakage of the magnetic suspension bearing 32 can be greatly reduced, and when the rotating shaft 5 moves axially, the double thrust plates provide stable and symmetrical suspension support for the rotating shaft 5 under the action of axial magnetic force provided by the axial control coil 3, so that the load control difficulty of axial and radial magnetic suspension is reduced.

In some embodiments, to achieve independent control of radial and axial magnetic levitation, the stator assembly 1 includes an outer bearing core 8, an inner bearing core 9, the inner bearing core 9 being disposed within the outer bearing core 8. Stator module 1 is fixed through outer bearing core 8 to carry on inner bearing core 9, set up radial control coil 2 and axial control coil 3 on the inner bearing core 9, thrust subassembly 4 can be rotatory for stator module 1 along with pivot 5, thereby realizes axial and radial three degrees of freedom to support.

In some embodiments, in order to enable the thrust assembly 4 to have good thrust capability, the opposite axial end faces of the first thrust plate 6 and the second thrust plate 7 are both thrust faces 10, an annular first stepped portion 11 and an annular second stepped portion 12 are arranged on the thrust faces 10, the first stepped portion 11 and the outer bearing iron core 8 are arranged correspondingly in the axial direction of the stator assembly 1, and are specifically located at two ends of the outer bearing iron core 8, and a step face gap between the outer bearing iron core 8 and the first stepped portion 11 generates electromagnetic force to realize control over the axial position of the rotating shaft 5; second step portion 12 corresponds the setting with interior bearing core 9 along stator module 1's axial, and second step portion 12 plays radial movement guard action, prevents thrust dish and stator module 1 axial dislocation, and under magnetic suspension bearing 32 outage state, second step portion 12 and stator module 1 contact play the effect of supporting thrust dish and pivot 5.

In some embodiments, the thrust surface 10 is further provided with a third stepped portion 13, the thrust assembly 4 further includes a rotor core 14, the rotor core 14 and the third stepped portion 13 are arranged in an axial direction of the stator assembly 1, the first thrust disk 6, the rotor core 14, and the second thrust disk 7 are shrink-fitted on the rotating shaft 5, and the rotor core 14 is compressed between the first thrust disk 6 and the second thrust disk 7. The third step 13 serves to press the lamination sheets of the rotor core 14 against being released in operation. When the rotating shaft 5 moves radially, the magnetic suspension bearing 32 can ensure the stability of the rotating shaft 5 through the electromagnetic force action of the rotor core 14.

In some embodiments, the first step part 11, the second step part 12 and the third step part 13 are concentrically arranged from the edge of the thrust surface 10 to the center of the thrust surface 10 in sequence, and the height of the third step part 13 is greater than the height of the second step part 12 is greater than the height of the first step part 11, and the whole thrust assembly 4 is wrapped on the stator assembly 1 in a U shape in a radial section.

In some embodiments, a permanent magnet ring 15 is provided between the inner bearing core 9 and the outer bearing core 8, the permanent magnet ring 15 being radially magnetized. The present embodiment adopts the permanent magnet ring 15 to provide the bias magnetic flux for the radial air gap and the axial air gap of the magnetic suspension bearing 32, and can realize the independent control of the radial and axial magnetic suspension load near the equilibrium position. Preferably, the permanent magnet ring 15 is annular magnetic steel, the material is 38UH, and the magnetic steel is magnetically adhered to the cylindrical surface of the outer circle of the inner bearing iron core 9, so that the upper end face and the lower end face of the permanent magnet ring 15 are flush with the upper end face and the lower end face of the inner axial iron core.

In some embodiments, the outer bearing core 8 includes a sleeve portion 16 and a flange portion 17, the outer bearing core 8 is fixedly mounted by the flange portion 17, the permanent magnet ring 15 is assembled in the sleeve portion 16, a first positioning ring 18 and a second positioning ring 19 are respectively disposed at two ends of the permanent magnet ring 15, and the first positioning ring 18 and the second positioning ring 19 tightly fix the permanent magnet ring 15 in the sleeve portion 16. Therefore, the permanent magnet ring 15 of the embodiment is closer to the edge of the stator assembly 1 than the axial control coil 3 and the radial control coil 2, the axial control magnetic flux and the radial control magnetic flux do not pass through the permanent magnet ring 15, demagnetization of the permanent magnet ring 15 is avoided, and reliability and service life of the permanent magnet ring 15 are improved.

In some embodiments, in order to improve the assembly stability of the inner bearing core 9 and the outer bearing core 8, the first positioning ring 18 and the second positioning ring 19 are greater than the permanent magnetic ring 15 along the radial thickness of the stator assembly 1, the first positioning ring 18 and the second positioning ring 19 can compress the edge of the inner bearing core 9, so that the first positioning ring 18 and the second positioning ring 19 perform axial positioning compression on the permanent magnetic ring 15, and also perform positioning compression function on the inner bearing core 9, so that the stator assembly 1 has a stable structure, and stable magnetic support is provided for the thrust assembly 4.

In some embodiments, the inner wall of the sleeve portion 16 is provided with an annular boss 20, the permanent magnet ring 15 is fitted on the annular boss 20, and the axial length of the annular boss 20 along the stator assembly 1 is the same as the axial length of the permanent magnet ring 15 along the stator assembly 1. The annular boss 20 can play a role in positioning the first positioning ring 18 and the second positioning ring 19 for hot sleeve assembly, and the positioning rings are clamped left and right after being fixed, so that the position fixation of the magnetic steel and the inner bearing iron core 9 is ensured.

In some embodiments, the axial clearance of the first positioning ring 18 and the first thrust disk 6 is smaller than the axial clearance of the outer bearing core 8 and the first thrust disk 6, and the first positioning ring 18 and the second step portion 12 of the first thrust disk 6 have a radial clearance, the axial clearance of the second positioning ring 19 and the second thrust disk 7 is smaller than the axial clearance of the outer bearing core 8 and the second thrust disk 7, and the second positioning ring 19 and the second step portion 12 of the second thrust disk 7 have a radial clearance. Compared with the outer bearing core 8 and the inner bearing core 9, the first positioning ring 18 and the second positioning ring 19 are closer to the thrust surface 10, and have radial gaps with the second step part 12, so that the axial and radial protection effects can be achieved.

In some embodiments, the first retaining ring 18 and the second retaining ring 19 are made of aluminum. The aluminum material has high magnetic conductivity, and the magnetic flux in the magnetic suspension bearing 32 cannot be lost.

In some embodiments, the outer bearing core 8 includes a first core body 21 and a second core body 22 that are symmetrically disposed. This embodiment is with two iron core bodies of outer bearing core 8 symmetry respectively, and permanent magnetic ring 15 is in just on the plane of symmetry of two iron core bodies, and the magnetic flux of permanent magnet can be followed the even two directions transmission to first iron core body 21 and second iron core body 22 of plane of symmetry, forms symmetrical magnetic circuit for the magnetic leakage reduces and the magnetic circuit is stable, reduces the load control degree of difficulty. Meanwhile, the annular bosses 20 on the inner wall of the sleeve portion 16 are respectively arranged on the two iron core bodies and formed by splicing the two iron core bodies, and the axial length of the boss on each iron core body is equal to half of the axial length of the permanent magnet ring 15. Moreover, divide into first iron core body 21 and second iron core body 22 with outer bearing core 8, can be convenient for the manufacturing of outer bearing core 8, during the assembly permanent magnetic ring 15, holding ring, inner bearing core 9 can make things convenient for more accurate suit in outer bearing core 8, improve magnetic suspension bearing's assembly production efficiency.

In some embodiments, the inner bearing core 9 is provided with a shaft hole 23, a wire groove 24 is provided on the inner wall of the shaft hole 23, and the radial control coil 2 is wound in the wire groove 24. Preferably, the wire chase 24 is a trapezoidal groove. The notch of the trapezoidal wire groove 24 is smaller, so that the radial force of the rotating shaft 5 can be effectively improved.

In some embodiments, the inner bearing core 9 is provided with a first coil bobbin 25 and a second coil bobbin 26 on two axial end surfaces, respectively, the axial control coil 3 includes a first axial coil 27 and a second axial coil 28, the first axial coil 27 is wound in the first coil bobbin 25, and the second axial coil 28 is wound in the second coil bobbin 26. The axial control coil 3 is assembled by adopting a framework, so that the shape, reliability and assembly convenience of the axial control coil 3 are ensured. An axial coil is arranged corresponding to each thrust disc, so that the axial supporting effect of the magnetic suspension bearing 32 is improved.

In some embodiments, the first coil bobbin 25 and the second coil bobbin 26 are respectively mounted in mounting holes 30 of the inner bearing core 9 through mounting posts 29, and the mounting holes 30 are uniformly arranged along the circumferential direction of the inner bearing core 9. In this embodiment, the inner bearing core 9 has four through holes to ensure the positioning fit of the axial frame.

Inner bearing iron core 9 is folded through 35SW1900 silicon steel sheet and is pressed the formation, the external diameter is circular, trapezoidal wire casing 24 increases the bearing radial power that exerts with this increase magnetic pole area, radial control coil 2 is through inlaying line mode cover iron core department, compress tightly through whole line and ensure that the coil is fixed on inner bearing iron core 9, axial control coil 3 is stereotyped through the skeleton and is fixed with the radial positioning fit of inner bearing iron core 9 mounting hole 30, fitting surface department adopts AB glue to bond, ensure that 3 assembles of axial control coil are reliable, accomplish the assembly of subassembly in the bearing.

The outer bearing iron core 8 is made of 45 steel, the first positioning ring 18, the second positioning ring 19 and the outer bearing iron core 8 are in interference fit, the outer bearing iron core 8 is heated to 180 ℃ according to the interference fit amount of the first positioning ring 18 and the first iron core body 21, heat is preserved for 1 hour, the end face of the first positioning ring 18 is attached to the non-boss end face of the first iron core body 21, and the first outer bearing assembly is assembled after cooling. The same procedure completes the assembly of the second outer bearing assembly including the second locating ring 19 and the second core body 22.

Heating the two outer bearing assemblies to 120 ℃, matching the bearing inner assembly with the two outer bearing assemblies and the permanent magnet ring 15 left and right, locking by using the flange part 17 of the outer bearing iron core 8, and completing the assembly of the stator assembly 1 after cooling.

The thrust assembly 4 is characterized in that the first thrust plate 6 and the rotor core 14 are sleeved into the rotating shaft 5 in a hot mode, then the stator assembly 1 is assembled and fixed, the stator assembly 1 is fixed on the machine shell 31 in a locking mode through threads, then the other thrust plate is sleeved in a hot mode, and after cooling is conducted, the whole magnetic suspension bearing 32 is assembled.

Fig. 7 is an axial magnetic circuit diagram, and the bias magnetic field path provided by the permanent magnet ring 15 is as follows: permanent magnet ring 15-outer bearing iron core 8-axial air gap-thrust disk-rotor iron core 14-radial air gap-inner bearing iron core 9-permanent magnet ring 15, axial control coil 3 provides the magnetic field path: rotor core 14-thrust disk-axial air gap-outer bearing core 8-axial air gap-thrust disk-bearing rotor. The axial control magnetic field does not pass through the permanent magnet ring 15.

In the radial magnetic circuit diagram of fig. 8, the bias magnetic field path provided by the permanent magnet ring 15 is: the permanent magnet ring 15-the outer bearing iron core 8-the axial air gap-the thrust plate-the rotor iron core 14-the radial air gap-the inner bearing iron core 9-the permanent magnet ring 15, the radial control coil 2 provides the control magnetic field path: rotor core 14-inner bearing core 9-rotor core 14. The axial control magnetic field does not pass through the permanent magnet ring 15.

A bearing system comprising the magnetic bearing 32 described above. The bearing system of the embodiment may adopt two magnetic suspension bearings 32 with three degrees of freedom, and may also adopt an existing radial magnetic suspension bearing and one magnetic suspension bearing 32 with three degrees of freedom of the present disclosure, so as to realize axial and radial support of the motor rotating shaft.

An electric machine comprising a magnetic bearing 32 as described above.

In some embodiments, the motor further includes a housing 31, and when the outer bearing core 8 is included and the flange portion 17 is provided on the outer bearing core 8, the flange portion 17 of the outer bearing core 8 is fixedly assembled on the housing 31. The flange portion 17 is provided with a fixing hole 34, and the flange portion 17 is fixed on the housing 31 through a screw 33 inserted into the fixing hole 34.

The motor disclosed by the invention adopts the three-degree-of-freedom magnetic suspension bearing 32, only two bearing assemblies can be used, the axial length of the rotating shaft 5 is greatly reduced, and the fixed frequency and the rigidity of the rotating shaft 5 are improved, so that the critical rotating speed of the rotating shaft 5 of the motor is improved.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present disclosure is to be considered as limited only by the preferred embodiments and not limited to the specific embodiments described herein, and all changes, equivalents and modifications that come within the spirit and scope of the disclosure are desired to be protected. The foregoing is only a preferred embodiment of the present disclosure, and it should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principle of the present disclosure, and these improvements and modifications should also be considered as the protection scope of the present disclosure.

Claims

1. A magnetic bearing, comprising:

the stator assembly (1), the said stator assembly (1) is equipped with the radial control coil (2), axial control coil (3);

the thrust assembly (4) is assembled on the rotating shaft (5), the thrust assembly (4) comprises a first thrust disc (6) and a second thrust disc (7), and the first thrust disc (6) and the second thrust disc (7) are symmetrically arranged at two axial ends of the stator assembly (1);

the stator assembly (1) is configured to provide three degrees of freedom of levitation support for the shaft (5) through the thrust assembly (4).

2. Magnetic bearing according to claim 1, characterized in that the stator assembly (1) comprises an outer bearing core (8), an inner bearing core (9), the inner bearing core (9) being arranged within the outer bearing core (8).

3. The magnetic suspension bearing according to claim 2, wherein the opposite axial end faces of the first thrust plate (6) and the second thrust plate (7) are both thrust faces (10), a first step part (11) and a second step part (12) are arranged on each thrust face (10), the first step part (11) and the outer bearing core (8) are arranged along the axial direction of the stator assembly (1) correspondingly, and the second step part (12) and the inner bearing core (9) are arranged along the axial direction of the stator assembly (1) correspondingly.

4. The magnetic suspension bearing according to claim 3, wherein a third step part (13) is further arranged on the thrust surface (10), the thrust assembly (4) further comprises a rotor core (14), the rotor core (14) and the third step part (13) are arranged along the axial direction of the stator assembly (1), the first thrust disk (6), the rotor core (14) and the second thrust disk (7) are shrink-fitted on the rotating shaft (5), and the rotor core (14) is compressed between the first thrust disk (6) and the second thrust disk (7).

5. Magnetic bearing according to claim 3, characterized in that the first step (11), the second step (12) and the third step (13) are arranged concentrically in sequence from the edge of the thrust surface (10) towards the center of the thrust surface (10).

6. Magnetic bearing according to claim 2, characterized in that a permanent magnet ring (15) is arranged between the inner bearing core (9) and the outer bearing core (8), the permanent magnet ring (15) being magnetized in the radial direction.

7. The magnetic suspension bearing according to claim 6, characterized in that the outer bearing core (8) comprises a sleeve portion (16) and a flange portion (17), the outer bearing core (8) is fixedly mounted by the flange portion (17), the permanent magnet ring (15) is assembled in the sleeve portion (16), a first positioning ring (18) and a second positioning ring (19) are respectively arranged at two ends of the permanent magnet ring (15), and the first positioning ring (18) and the second positioning ring (19) tightly press and fix the permanent magnet ring (15) in the sleeve portion (16).

8. Magnetic suspension bearing according to claim 7, characterized in that the thickness of the first positioning ring (18) and the second positioning ring (19) in the radial direction of the stator assembly (1) is greater than the thickness of the permanent magnet ring (15) in the radial direction of the stator assembly (1), and the first positioning ring (18) and the second positioning ring (19) can press and fix the edge of the inner bearing core (9).

9. Magnetic bearing according to claim 7, characterized in that the inner wall of the sleeve portion (16) is provided with an annular boss (20), the permanent magnet ring (15) is fitted on the annular boss (20), and the axial length of the annular boss (20) along the stator assembly (1) is the same as the axial length of the permanent magnet ring (15) along the stator assembly (1).

10. Magnetic suspension bearing according to claim 7, characterized in that the axial clearance of the first positioning ring (18) from the first thrust disk (6) is smaller than the axial clearance of the outer bearing core (8) from the first thrust disk (6), and the axial clearance of the second positioning ring (19) from the second thrust disk (7) is smaller than the axial clearance of the outer bearing core (8) from the second thrust disk (7); and/or the first positioning ring (18) and the second positioning ring (19) are made of aluminum materials.

11. Magnetic bearing according to claim 2, characterized in that the outer bearing core (8) comprises a first core body (21), a second core body (22) arranged symmetrically.

12. Magnetic bearing according to any of claims 2-11, wherein the inner bearing core (9) is provided with a shaft hole (23), the inner wall of the shaft hole (23) is provided with a wire slot (24), and the radial control coil (2) is wound in the wire slot (24).

13. Magnetic bearing according to claim 12, characterized in that the wire groove (24) is a trapezoidal groove.

14. The magnetic suspension bearing according to claim 12, wherein a first coil bobbin (25) and a second coil bobbin (26) are respectively disposed on two axial end faces of the inner bearing core (9), the axial control coil (3) comprises a first axial coil (27) and a second axial coil (28), the first axial coil (27) is wound in the first coil bobbin (25), and the second axial coil (28) is wound in the second coil bobbin (26).

15. Magnetic bearing according to claim 14, characterized in that the first coil bobbin (25) and the second coil bobbin (26) are mounted in mounting holes (30) of the inner bearing core (9) by means of mounting posts (29), respectively, the mounting holes (30) being arranged uniformly in the circumferential direction of the inner bearing core (9).

16. A bearing system, characterized in that it comprises a magnetic bearing (32) according to any of claims 1 to 15.

17. An electric machine, characterized in that it comprises a magnetic bearing (32) according to any of claims 1-15.

18. The electric machine according to claim 17, characterized in that the electric machine further comprises a housing (31), and when the outer bearing core (8) is included and the flange portion (17) is provided on the outer bearing core (8), the flange portion (17) of the outer bearing core (8) is fixedly fitted on the housing (31).