CN117028416A

CN117028416A - Magnetic bearing and pump device

Info

Publication number: CN117028416A
Application number: CN202311062470.6A
Authority: CN
Inventors: 饶俊
Original assignee: Minimally Invasive Surgery Medical Technology Shanghai Co ltd
Current assignee: Minimally Invasive Surgery Medical Technology Shanghai Co ltd
Priority date: 2023-08-22
Filing date: 2023-08-22
Publication date: 2023-11-10

Abstract

The present application provides a magnetic bearing and a pump device, the magnetic bearing comprising: a rotor and a stator, the stator circumferentially disposed about the rotor; the rotor has a central axis and is a rotor permanent magnet; the stator includes: at least two pairs of radial stator poles, the radial stator poles being evenly distributed along the circumference of the rotor; and a stator coil correspondingly wound on each of the at least two pairs of radial stator poles. The application provides a magnetic bearing and a pump device, which enable the structure of the magnetic bearing to be more compact and concise, and can miniaturize the magnetic bearing without reducing the performance of the magnetic bearing, thereby increasing the application prospect of the magnetic bearing.

Description

Magnetic bearing and pump device

Technical Field

The application relates to the technical field of bearings, in particular to a magnetic bearing and a pump device.

Background

The magnetic bearing is also called as magnetic suspension bearing, which is a novel high-performance bearing, and the rotor is suspended in the air by utilizing the magnetic force action, so that the rotor and the stator have no mechanical contact structure. Compared with the traditional rolling bearing, sliding bearing and oil film bearing, the magnetic bearing has the advantages of small noise, long service life, lubrication free, no oil pollution and the like, and is particularly suitable for special environments such as high speed, vacuum, ultra-clean and the like.

Current magnetic bearings can be divided into two categories according to the source of the bias magnetic field: the first type is an active magnetic bearing. A bias current needs to be applied to such a magnetic bearing coil to provide a bias magnetic field. The additional control current provides controllable magnetic buoyancy, and the magnetic bearing of the type is relatively large in size, weight and power consumption, and is not suitable for microminiaturization. The second type is a permanent magnet bias magnetic suspension bearing, the bias magnetic field of the magnetic suspension bearing is generated by a permanent magnet, and the electromagnet only provides a control magnetic field for balancing load or interference, so that the volume is obviously reduced. Compared with an active magnetic suspension bearing, the magnetic suspension bearing reduces the extra power consumption caused by the bias current, and the whole volume of the magnetic bearing is also reduced due to the reduction of the volume of the electromagnet coil, thereby providing possibility for miniaturized product application.

The existing permanent magnet bias magnetic suspension bearing can be roughly divided into two types according to the integration level of the control module: one is to adopt independent magnetic bearing modules in the axial direction and the radial direction to realize five-degree-of-freedom support, and the design mode ensures that the whole axial dimension is longer, and the system complexity is higher; the other is to integrate radial and axial magnetic bearing modules, but the design generally leads to complex rotor structure design, larger radial size of the stator, lower or nearly no passive control rigidity of axial and rolling, larger power consumption of the magnetic bearing and unsuitable microminiaturization.

Therefore, it is necessary to provide a new magnetic bearing structure, miniaturize the magnetic bearing without degrading the performance of the magnetic bearing, and increase the application prospect of the magnetic bearing.

Disclosure of Invention

The application provides a magnetic bearing and a pump device, which can miniaturize the magnetic bearing without reducing the performance of the magnetic bearing and increase the application prospect of the magnetic bearing.

One aspect of the present application provides a magnetic bearing comprising: a rotor and a stator, the stator circumferentially disposed about the rotor; the rotor has a central axis and is a rotor permanent magnet; the stator includes: at least two pairs of radial stator poles, the radial stator poles being evenly distributed along the circumference of the rotor; and a stator coil correspondingly wound on each of the at least two pairs of radial stator poles.

In some embodiments of the application, the magnetic bearing further comprises: an active control system configured to provide active stability control with respect to radial displacement of the rotor, the active control system comprising: a displacement sensor for detecting a radial offset of the rotor; and a controller configured to output a control current to the stator coil to return the radial offset of the rotor to within an offset threshold when the radial offset detected by the displacement sensor is greater than the offset threshold.

In some embodiments of the application, the radial stator poles are not in magnetic communication with each other.

In some embodiments of the application, the rotor permanent magnets are magnetized in the direction of the central axis.

In some embodiments of the application, the ratio of the outer diameter of the rotor to the axial height of the rotor is greater than or equal to 1.5.

In some embodiments of the application, the ratio of the outer diameter to the inner diameter of the rotor is greater than or equal to 1.1.

In some embodiments of the application, the ratio of the absolute value of the difference between the height of the rotor permanent magnets and the height of the radial stator poles to the height of the radial stator poles is less than or equal to 70%.

In some embodiments of the application, the spacing between the rotor and the stator is less than or equal to 10% of the outer diameter of the rotor.

In some embodiments of the present application, the radial stator pole has a "concave" shape, a concave portion of the "concave" shape faces the rotor and is formed as a mounting groove, the stator coil is wound in the mounting groove, and upper and lower sides in an axial direction of the mounting groove are respectively defined as upper teeth and lower teeth.

In some embodiments of the application, the ratio of the absolute value of the difference between the upper tooth height and the lower tooth height of the radial stator pole to the lower tooth height is less than or equal to 80%.

In some embodiments of the application, the ratio of the diameter of the circle enclosed by the upper teeth of the at least two pairs of radial stator poles to the diameter of the circle enclosed by the lower teeth of the at least two pairs of radial stator poles is less than or equal to 20%.

In some embodiments of the application, the rotor is integrally annular and is made of only one permanent magnet material.

In some embodiments of the application, the material of the rotor permanent magnet is rubidium-iron-boron and/or the material of the radial stator pole is a magnetically permeable ferromagnetic material.

Another aspect of the present application also provides a pump apparatus comprising: a pump head housing; the impeller is arranged inside the pump head shell; the rotor of the magnetic bearing as described above, the rotor being disposed inside the pump head housing, the magnetic bearing being configured to drive the impeller to rotate about the central axis.

In some embodiments of the application, the pump device comprises: a stator of a magnetic bearing as described above; a pump housing; the driving device is arranged in the pump shell and is used for providing a rotating force for the magnetic bearing; the stator of the magnetic bearing is arranged in the pump casing, and the pump head casing is detachably connected with the pump casing.

In some embodiments of the application, the rotor of the magnetic bearing is disposed within an annular recess defined by the pump head housing, and the drive means is proximate one end of the rotor, extends into a space defined by the pump head housing outside of the annular recess for receiving the rotor, and is surrounded by the rotor.

In some embodiments of the application, the stator is disposed about an annular recess of the pump head housing for receiving the rotor, and a pump head mount is disposed within the pump head housing for receiving at least a portion of the pump head housing, at least a portion of the pump head mount being complementary in shape to at least a portion of the pump head housing.

The application provides a magnetic bearing and a pump device, which enable the structure of the magnetic bearing to be more compact and concise, and can miniaturize the magnetic bearing without reducing the performance of the magnetic bearing, thereby increasing the application prospect of the magnetic bearing.

Drawings

The following drawings describe in detail exemplary embodiments disclosed in the present application. Wherein like reference numerals refer to like structure throughout the several views of the drawings. Those of ordinary skill in the art will understand that these embodiments are non-limiting, exemplary embodiments, and that the drawings are for illustration and description only and are not intended to limit the scope of the application, as other embodiments may equally well accomplish the inventive intent in this disclosure. It should be understood that the figures are for illustrative purposes and are not to be understood as being drawn to scale. Wherein:

FIG. 1 is a top view of a magnetic bearing according to an embodiment of the present application;

FIG. 2 is a schematic view of a longitudinal cross-sectional structure of a magnetic bearing according to an embodiment of the present application along the line A-A in FIG. 1;

FIG. 3 is a schematic diagram of the bias magnetic field principle based on the longitudinal section of the magnetic bearing according to the embodiment of the application;

FIG. 4 is a schematic diagram of an axial passive control magnetic circuit based on the longitudinal section of the magnetic bearing according to the embodiment of the application;

FIG. 5 is a schematic diagram of a roll passive control magnetic circuit based on a longitudinal cross section of the magnetic bearing according to an embodiment of the present application;

FIG. 6 is a schematic diagram of a radial active control magnetic circuit based on the longitudinal section of the magnetic bearing according to the embodiment of the application;

fig. 7 is a schematic structural view of a pump device according to an embodiment of the present application.

Detailed Description

The following description provides specific applications and requirements of the application to enable any person skilled in the art to make and use the application. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the application. Therefore, the present application is not limited to the embodiments shown, but is to be accorded the widest scope possible within the scope of the claims.

The technical scheme of the application is described in detail below with reference to the examples and the accompanying drawings.

FIG. 1 is a top view of a magnetic bearing according to an embodiment of the present application. Fig. 2 is a schematic longitudinal sectional view of a magnetic bearing according to an embodiment of the present application. Specifically, FIG. 2 is a longitudinal cross-sectional view taken along the dashed line A-A in FIG. 1. The magnetic bearing according to the embodiment of the present application will be described in detail with reference to the accompanying drawings.

An embodiment of the present application provides a magnetic bearing 100, as shown with reference to fig. 1 and 2, comprising: a rotor 10 and a stator 20, the stator 20 being circumferentially disposed around the rotor 10, the stator 20 being configured to provide passive stability control with respect to axial and angular displacement of the rotor 10 and active stability control of radial displacement.

In some embodiments of the application, the spacing between the rotor 10 and the stator 20 is less than or equal to 10% of the outer diameter of the rotor. In general, for the purpose of the miniature magnetic bearing, a way of changing the material or composition of each rotor or stator is adopted by a person skilled in the art, but the size and dimension relationship between the components of the magnetic bearing are not studied to realize the miniature magnetic bearing, and meanwhile, the performance of the magnetic bearing is maintained. The inventors of the present application creatively adopted completely different research paths, and surprisingly found that the relationship between the rotor and stator and the rotor diameter has a direct effect on the performance of the magnetic bearing during the development process, and in particular, by setting the gap between the rotor 10 and the stator 20 to be less than or equal to 10% of the outer diameter of the rotor, a miniaturized magnetic bearing can be realized without reducing or improving the performance of the magnetic bearing, and the design of the whole magnetic bearing is made more compact.

With continued reference to fig. 1 and 2, the rotor 10 is generally annular, e.g., circular, and the rotor 10 has a central axis Z about which the rotor 10 is configured to rotate, and in particular applications, a rotary actuator (not shown) may be provided within the annular region of the rotor 10, e.g., various types of motors that may be employed by those skilled in the art based on the general principles of the present disclosure.

With continued reference to fig. 2, the rotor 10 is a rotor permanent magnet 12. In this embodiment, the rotor permanent magnet 12 has a ring shape.

In some embodiments of the application, the rotor permanent magnets 12 are magnetized in the direction of the central axis.

In some embodiments of the application, the rotor 10 (rotor permanent magnets 12) is integrally ring-shaped and made of only one permanent magnet material. The rotor 10 having such a structure can significantly simplify the structure of the entire magnetic bearing, and is advantageous for further realizing a miniaturized magnetic bearing.

In some embodiments of the present application, the material of the rotor permanent magnet 12 comprises rubidium-iron-boron.

In some embodiments of the application, the ratio of the outer diameter of the rotor 10 (i.e., the outer diameter of the rotor permanent magnets 12) to the axial height H1 of the rotor 10 (i.e., the height of the rotor permanent magnets 12) is greater than or equal to 1.5.

In some embodiments of the application, the ratio of the outer diameter to the inner diameter of the rotor 10 (i.e., the outer diameter to the inner diameter of the rotor permanent magnets 12) is greater than or equal to 1.1.

With continued reference to fig. 1 and 2, the stator 20 includes: at least two pairs of radial stator poles 21, the radial stator poles 21 being uniformly distributed along the circumferential direction of the rotor 10; a stator coil 22 is correspondingly wound on each of the at least two pairs of radial stator poles 21.

In some embodiments of the application, the radial stator poles 21 are not in magnetic communication with each other. I.e. each radial stator pole 21 is independent on the magnetic circuit. That is, no magnetic conductive part is connected between the at least two pairs of radial stator poles 21, which is beneficial to the arrangement of the magnetic suspension bearing with simple structure and smaller volume.

In some embodiments of the application, the material of the radial stator poles 21 comprises magnetically permeable ferromagnetic material. A pair of radial stator poles 21 refers to two radial stator poles 21 that are symmetrical about the central axis Z.

In some embodiments of the present application, the number of the radial stator poles 21 may be 3 or more, preferably an even number of 4 or more, and uniformly distributed around the rotor 10.

In some embodiments of the application, the ratio of the absolute value of the difference between the height H1 of the rotor permanent magnets 12 and the height H2 of the radial stator poles 21 to the height H2 of the radial stator poles 21 is less than or equal to 70%. That is, |H2-H2|/H2.ltoreq.0.3.

In some embodiments of the present application, referring to fig. 2, the radial stator pole 21 has a "concave" shape, a concave portion of the "concave" shape faces the rotor 10 and is formed as a mounting groove, and the stator coil 22 is wound in the mounting groove, and the upper and lower sides of the mounting groove in the axial direction are defined as upper teeth and lower teeth, respectively.

In some embodiments of the present application, the ratio of the absolute value of the difference between the upper tooth height h1 and the lower tooth height h2 of the radial stator pole 21 to the lower tooth height h2 is less than or equal to 80%. That is, |h1-h2|/h2.ltoreq.0.8.

In some embodiments of the present application, the ratio of the diameter D1 of the circle enclosed by the upper teeth of the at least two pairs of radial stator poles 21 to the diameter D2 of the circle enclosed by the lower teeth of the at least two pairs of radial stator poles 21 is less than or equal to 20%. That is, |D1-D2|/D2.ltoreq.0.2.

In other embodiments of the present application, the radial stator pole 21 may also have an "i" shape, and recesses on two sides of the "i" shape are mounting grooves.

In some embodiments of the present application, the side of the radial stator pole 21 facing the rotor 10 may be further provided with a stator permanent magnet and a stator soft iron in sequence. In some embodiments of the application, the material of the stator permanent magnet comprises rubidium-iron-boron. In some embodiments of the application, the material of the stator soft iron comprises pure iron or silicon steel. The stator permanent magnets are magnetized in the radial direction of the rotor.

In some embodiments of the application, the stator coils 22 on both radial stator poles of each pair 21 are wound in opposite directions and are connected in series with each other. In other embodiments of the present application, the stator coils 22 on both radial stator poles of each pair of radial stator poles 21 are not necessarily connected in series with each other, and opposite currents may be respectively connected, so long as both radial stator poles of each pair of radial stator poles 21 are capable of generating magnetic fields in opposite directions when the currents are connected.

In some embodiments of the present application, the magnetic bearing 100 further comprises: an active control system (not shown in the figures) configured to provide active stability control with respect to radial displacement of the rotor 10, the active control system comprising: a displacement sensor for detecting a radial offset of the rotor 10; and a controller configured to output a control current to the stator coil 24 to return the radial offset of the rotor 10 to within an offset threshold when the radial offset detected by the displacement sensor is greater than the offset threshold, receiving a detection result of the displacement sensor. As will be appreciated by those skilled in the art in light of this disclosure, the primary control system may be applied to the magnetic bearing control of the present application and will not be described in detail herein.

Fig. 3 is a schematic diagram of a bias magnetic field principle based on the longitudinal section of the magnetic bearing according to the embodiment of the application. It should be noted that, for the sake of brevity, the magnetic path and the reference numerals are omitted in fig. 3, and reference numerals corresponding to fig. 2 may be referred to.

Referring to fig. 3, the magnetic path 30 shown in fig. 3 is generated by the rotor permanent magnet 12 and the radial stator pole 21. The method is mainly used for establishing a static bias magnetic field. Since the rotor permanent magnet 12 is magnetized in the axial direction and the magnetic path between the rotor permanent magnet and the radial stator pole 21 is short and low in magnetic resistance, a high-strength bias magnetic field can be established.

Fig. 4 is a schematic diagram of an axial passive control magnetic circuit based on the longitudinal section of the magnetic bearing according to the embodiment of the application.

Referring to fig. 3 and 4, the axial stiffness of the rotor 10 is the passive axial stiffness provided by the bias magnetic field. When the rotor 10 is in an axially balanced position (shown in fig. 3), the rotor 10 is axially unstressed due to the axial structural symmetry. When the rotor 10 is subjected to a downward disturbing force (shown in fig. 4), the rotor 10 is displaced downward. The permanent magnetic force generated by the bias field will pull the rotor 10 back to the equilibrium position.

Fig. 5 is a schematic diagram of a roll passive control magnetic circuit based on the longitudinal section of the magnetic bearing according to an embodiment of the present application.

As shown with reference to fig. 3 and 5, the roll stiffness of the rotor 10 is a passive roll stiffness provided by a bias magnetic field. When the rotor 10 is in the equilibrium position (shown in fig. 3), the rotor shaft is not subject to torque due to structural symmetry. When the rotor 10 is disturbed, a deflection of the central axis Z (in the clockwise direction in fig. 5) occurs. At this time, the corresponding rotor permanent magnet and radial stator poles are dislocated, and the permanent magnetic force generated by the bias magnetic field generates a counter-clockwise restoring moment to pull the rotor 10 back to the equilibrium position.

Fig. 6 is a schematic diagram of a radial active control magnetic circuit of a magnetic bearing according to an embodiment of the present application.

Referring to fig. 3 and 6, when the rotor 10 is in the radial equilibrium position, due to the symmetry of the structure, the magnetic induction intensity generated by the bias magnetic field in the radial magnetic gap is equal, and thus the permanent magnetic force generated by the bias magnetic field is equal in the radial direction, and the rotor 10 is in the equilibrium position (as shown in fig. 3). If the rotor 10 is subjected to a disturbing force to the right, the rotor 10 will deviate from the equilibrium position, displacing to the right (as shown in fig. 6), whereby the magnetic gap to the left is larger than the magnetic gap to the right. The magnetic induction intensity on the left side is reduced, and the magnetic induction intensity on the right side is increased. When the magnetic pole area is fixed, the magnetic force is proportional to the square of the magnetic induction intensity. Therefore, the right side of the permanent magnetic force generated by the bias magnetic field is larger than the left side, and the rotor 10 cannot return to the equilibrium position autonomously. At this time, the offset of the rotor 10 from the radial balance position is detected by a non-contact displacement sensor (not shown) arranged in the radial direction of the rotor 10 and sent to the controller. The displacement signal is converted into a control signal by the controller, and the control signal is converted into a control current through the power amplifier to be supplied to the stator coils of the left and right radial stator poles, thereby generating a control magnetic field 40 as shown in fig. 6. The magnetic induction generated by the control magnetic field is superimposed and enhanced in the radial magnetic gap on the left and is superimposed and weakened in the radial magnetic gap on the right, and the magnetic force in the left magnetic gap is larger than that in the right magnetic gap at this time, so that the rotor 10 is pulled back to the radial balance position shown in fig. 3.

In the technical scheme of the application, the rotor permanent magnet 12 magnetized in the axial direction is utilized to provide a static bias magnetic field. The magnetic circuits of the rotor 10 and the stator 20 are simple, so that the magnetic resistance is small, the radial active control efficiency is higher than that of the traditional magnetic suspension bearing, the control current of the radial active control is greatly reduced, and the power consumption of the whole system is greatly reduced. Furthermore, under the premise that the simple magnetic circuit enables sufficient passive control rigidity in the axial direction and the side-tipping direction, the whole system is very simple in structure, parts are obviously reduced relative to the traditional magnetic suspension bearing, the complexity of the system is greatly reduced, and microminiaturization is easy.

According to the technical scheme, the efficient active and passive control can be realized by only matching the annular rotor permanent magnet 12 with the radial stator pole 21 made of the magnetic conductive material, and compared with any magnetic bearing design at present, the complexity of the system is greatly reduced, so that the system is extremely simple.

The application provides the magnetic bearing, so that the structure of the magnetic bearing is more compact and concise, the magnetic bearing can be miniaturized under the condition of not reducing the performance of the magnetic bearing, and the application prospect of the magnetic bearing is increased.

An embodiment of the present application also provides a pump apparatus 200, as shown with reference to fig. 7, comprising: pump head housing 210; an impeller 220 disposed within the pump head housing 210 for pumping a fluid, such as blood; at least a portion of the magnetic bearing 100 as described above is disposed inside the pump head housing 210, and as shown in fig. 7, the rotor 10 of the magnetic bearing 100 is disposed in an annular groove 211 defined by the pump head housing 210. As will be appreciated by those skilled in the art in view of this disclosure, the magnetic bearing 100 is configured to rotate the impeller 220 about the central axis Z.

The pump device 200 according to the embodiment of the present application is, for example, a centrifugal blood pump.

The structure of the magnetic bearing 100 is described in detail above, and will not be described in detail here.

With continued reference to fig. 7, the pump apparatus 200 further includes: a driving means, such as a driving motor 230, is provided for providing a rotational force to the magnetic bearing 100, and at least a portion of the driving motor 230, such as near one end of the rotor 10, protrudes outside an annular recess 211 defined by the pump head housing 210 for accommodating the rotor 10 and is surrounded by the rotor 10.

With continued reference to fig. 7, the pump apparatus 200 further includes: a pump housing 240 for accommodating the driving motor 230 and at least a portion of the magnetic bearing 100, as shown in fig. 7, the stator 20 is accommodated in the pump housing 240 such that the stator 20 surrounds the pump head housing 210 for accommodating the annular groove 211 of the rotor 10. The pump head housing 210 is removably coupled to the pump housing 240. A pump head mount 241 for receiving at least a portion of the pump head housing 210 is disposed within the pump housing 240, at least a portion of the pump head mount 241 being complementary in shape to at least a portion of the pump head housing 210.

According to the technical scheme, after the magnetic bearing structure is simplified, the magnetic bearing structure is more compact and concise, so that the magnetic bearing can be miniaturized, and the service life of the pump device can be prolonged.

The application provides a magnetic bearing and a pump device, the magnetic bearing structure is more compact and simple, the magnetic bearing can be miniaturized under the condition of not reducing the performance of the magnetic bearing, the application prospect of the magnetic bearing is increased, and the magnetic bearing can be applied to the artificial heart field with extremely high requirements on rotation and volume, for example, the centrifugal blood pump.

In view of the foregoing, it will be evident to those skilled in the art after reading this disclosure that the foregoing application may be presented by way of example only and may not be limiting. Although not explicitly described herein, those skilled in the art will appreciate that the present application is intended to embrace a variety of reasonable alterations, improvements and modifications to the embodiments. Such alterations, improvements, and modifications are intended to be within the spirit and scope of the exemplary embodiments of the application.

It should be understood that the term "and/or" as used in this embodiment includes any or all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present.

The term "permanent magnet" or "magnet" as used in this embodiment refers to a component made of a ferromagnetic material having a large remanence and a large coercivity and magnetized to serve as a source of a magnetic field, such as NeFeB, as is well known to those skilled in the art. As used herein, "soft iron" refers to a component made of a laminated or non-laminated ferromagnetic material having a small remanence and a small coercivity, such as pure iron, silicon steel, or Hiperco alloy, for guiding magnetic flux, as is well known to those skilled in the art.

It will be further understood that the terms "comprises," "comprising," "includes" or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be further understood that, although the terms first, second, third, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Thus, a first element in some embodiments could be termed a second element in other embodiments without departing from the teachings of the present application. Like reference numerals or like reference numerals designate like elements throughout the specification.

Furthermore, the present description describes example embodiments with reference to idealized example cross-sectional and/or plan and/or perspective views. Thus, differences from the illustrated shapes, due to, for example, manufacturing techniques and/or tolerances, are to be expected. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the exemplary embodiments.

Claims

1. A magnetic bearing, comprising:

a rotor and a stator, the stator circumferentially disposed about the rotor;

the rotor has a central axis and is a rotor permanent magnet;

the stator includes: at least two pairs of radial stator poles, the radial stator poles being evenly distributed along the circumference of the rotor; and a stator coil correspondingly wound on each of the at least two pairs of radial stator poles.

2. The magnetic bearing of claim 1, further comprising: an active control system configured to provide active stability control with respect to radial displacement of the rotor, the active control system comprising:

a displacement sensor for detecting a radial offset of the rotor;

and a controller configured to output a control current to the stator coil to return the radial offset of the rotor to within an offset threshold when the radial offset detected by the displacement sensor is greater than the offset threshold.

3. The magnetic bearing of claim 1, wherein the radial stator poles are not in magnetic communication with each other.

4. The magnetic bearing of claim 1, wherein the rotor permanent magnet is magnetized in a direction along the central axis.

5. The magnetic bearing of claim 1, wherein a ratio of an outer diameter of the rotor to an axial height of the rotor is greater than or equal to 1.5.

6. The magnetic bearing of claim 1, wherein the ratio of the outer diameter to the inner diameter of the rotor is greater than or equal to 1.1.

7. The magnetic bearing of claim 1, wherein a ratio of an absolute value of a difference between a height of the rotor permanent magnet and a height of the radial stator pole to the height of the radial stator pole is less than or equal to 70%.

8. The magnetic bearing of claim 1, wherein a spacing between the rotor and the stator is less than or equal to 10% of an outer diameter of the rotor.

9. The magnetic bearing of claim 1, wherein the radial stator pole has a "concave" shape, a concave portion of the "concave" shape faces the rotor and is formed as a mounting groove, the stator coil is wound in the mounting groove, and upper and lower sides in an axial direction of the mounting groove are defined as upper teeth and lower teeth, respectively.

10. The magnetic bearing of claim 9, wherein a ratio of an absolute value of a difference between an upper tooth height and a lower tooth height of the radial stator pole to the lower tooth height is less than or equal to 80%.

11. The magnetic bearing of claim 9, wherein a ratio of a diameter of a circle surrounded by the upper teeth of the at least two pairs of radial stator poles to a diameter of a circle surrounded by the lower teeth of the at least two pairs of radial stator poles is less than or equal to 20%.

12. A magnetic bearing according to claim 1, wherein the rotor is integrally annular and is made of only one permanent magnet material.

13. A magnetic bearing according to claim 1, wherein the material of the rotor permanent magnet is rubidium-iron-boron and/or the material of the radial stator poles is magnetically permeable ferromagnetic.

14. A pump apparatus, comprising:

a pump head housing; the impeller is arranged inside the pump head shell;

a rotor of a magnetic bearing as claimed in any one of claims 1 to 13, the rotor being disposed inside the pump head housing, the magnetic bearing being configured to rotate the impeller about the central axis.

15. The pump apparatus of claim 14, wherein the pump apparatus comprises:

a stator of a magnetic bearing as claimed in any one of claims 1 to 13;

a pump housing;

the driving device is arranged in the pump shell and is used for providing a rotating force for the magnetic bearing;

the stator of the magnetic bearing is arranged in the pump casing, and the pump head casing is detachably connected with the pump casing.

16. A pump apparatus according to claim 15, wherein the rotor of the magnetic bearing is disposed within an annular recess defined by the pump head housing, and the drive means is proximate one end of the rotor, extends into a space defined by the pump head housing outside of the annular recess for receiving the rotor, and is surrounded by the rotor.

17. A pump apparatus according to claim 16, wherein the stator is disposed about an annular recess of the pump head housing for receiving the rotor, and wherein a pump head mount is disposed within the pump housing for receiving at least a portion of the pump head housing, at least a portion of the pump head mount being complementary in shape to at least a portion of the pump head housing.