Octagonal mixed radial magnetic bearing

Abstract

The invention provides an octagonal mixed radial magnetic bearing, and belongs to the technical field of magnetic suspension bearings, the octagonal mixed radial magnetic bearing comprises a rotor assembly, a stator assembly and a coil winding, the rotor assembly is composed of a rotating shaft and a rotor iron core sleeving the rotating shaft; the stator assembly is composed of a stator iron core and permanent magnets, the stator iron core is composed of an octagonal annular magnet yoke and eight magnetic poles pointing to the centroid from the octagonal vertex, the widths of the magnetic poles are the same, and the permanent magnets are embedded in the magnetic poles; the coil windings are wound on the octagonal annular magnet yoke, and the coil windings are separated by two magnetic poles; radial air gaps are arranged between the rotor assembly and the magnetic poles. According to the octagonal mixed radial magnetic bearing, the problem that the number of winding turns of a coil is insufficient when an existing mixed radial magnetic bearing is small in size is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic suspension bearings, in particular to an octagonal hybrid radial magnetic bearing. Background Art

[0002] In the field of magnetic bearing technology, magnetic bearings are primarily categorized into three types, depending on the source of the magnetic force: permanent magnet bearings, electromagnetic bearings, and permanent biased magnetic bearings. Permanent magnet bearings rely on the attractive and repulsive forces between permanent magnet rings to maintain stable rotor suspension. However, due to the inherent properties of permanent magnet materials, permanent magnet bearings are difficult to adapt to high-speed applications and lack active control capabilities. Electromagnetic bearings, on the other hand, use electromagnetic coils to provide electromagnetic force to maintain stable rotor suspension. However, prolonged operation of the electromagnetic coils generates significant heat, which not only affects the operating efficiency of the equipment but can also adversely affect its stability and lifespan.

[0003] In order to overcome the limitations of the above-mentioned single type of magnetic bearings, hybrid magnetic bearings came into being. Hybrid magnetic bearings combine the advantages of permanent magnetic bearings and electromagnetic bearings, using permanent magnets to provide a static bias magnetic field to replace the static bias magnetic field of the electromagnetic winding in the electromagnetic bearing, while at the same time generating a control magnetic field through the electromagnetic coil to adjust the suspension position of the rotor. However, the existing hybrid radial magnetic bearings have various structures, and most designs wind the control winding on the magnetic pole. Due to the limitations of the coil cavity shape, when the size of the hybrid radial magnetic bearing is small, the number of turns wound on the coil may be insufficient, making it difficult to generate sufficient electromagnetic force to control the position balance of the rotor, thereby affecting the overall performance and stability of the magnetic bearing.

[0004] Therefore, developing a hybrid radial magnetic bearing that can effectively control the rotor position balance in a small size has become an urgent problem to be solved in the current field of magnetic levitation bearing technology. Summary of the Invention

[0005] The object of the present invention is to provide an octagonal hybrid radial magnetic bearing, which solves the problem of insufficient number of coil winding turns in existing hybrid radial magnetic bearings when the size is small.

[0006] To achieve the above object, the present invention provides an octagonal hybrid radial magnetic bearing, comprising a rotor assembly, a stator assembly and a coil winding.

[0007] The rotor assembly is composed of a rotating shaft and a rotor core sleeved on the rotating shaft;

[0008] The stator assembly is composed of a stator core and a permanent magnet. The stator core is composed of an octagonal annular yoke and eight magnetic poles pointing from the octagonal vertices to the centroid. The magnetic poles have the same width and are embedded with permanent magnets.

[0009] The coil windings are wound on an octagonal annular magnetic yoke, and the coil windings are separated by two magnetic poles;

[0010] A radial air gap is provided between the rotor assembly and the magnetic poles.

[0011] Preferably, the rotor core and the stator core are both integral structures or stacked structures of silicon steel sheets.

[0012] Preferably, the width of the yoke is not less than the width of the magnetic pole.

[0013] Preferably, the permanent magnet is magnetized along the radial direction of the magnetic pole, and the magnetization direction is arranged in NNSSNNSS.

[0014] Preferably, the coil windings are connected in parallel, and the coil windings are wound on a yoke between two magnetic poles of a permanent magnet with opposite magnetization directions.

[0015] Preferably, the rotor core and the stator core are both made of ferromagnetic materials, and the permanent magnets are made of rare earth permanent magnet materials.

[0016] Therefore, the present invention adopts the above-mentioned octagonal hybrid radial magnetic bearing, and the technical effects are as follows:

[0017] 1. Solving the problem of insufficient coil turns: By winding the coil winding on an octagonal magnetic yoke instead of directly on the magnetic poles, the problem of insufficient coil turns in smaller hybrid radial magnetic bearings is effectively solved, thereby generating sufficient electromagnetic force to control the position balance of the rotor.

[0018] 2. Reduce the current demand of the electromagnetic coil: The permanent magnet embedded in the magnetic pole provides bias flux, which reduces the current demand in the electromagnetic coil, thereby reducing the heat generated by the electromagnetic coil when it is powered on for a long time and improving the operating efficiency and stability of the equipment.

[0019] 3. The permanent magnet is magnetized along the pole radial direction, and the magnetization direction is arranged in a specific manner, which can form a more uniform and stable bias magnetic field between the poles, further reducing the magnetic flux leakage and magnetic circuit coupling phenomenon, and improving the utilization rate of the magnetic field.

[0020] 4. Precise control of the rotor assembly: The four coil windings are connected in parallel, which facilitates controller design. The current size and direction in each coil winding can be independently controlled, thereby accurately adjusting the magnetic field strength generated by each winding and achieving precise control of the rotor assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of an octagonal hybrid radial magnetic bearing;

[0022] Figure 2is the magnetization direction of the permanent magnet of an octagonal hybrid radial magnetic bearing;

[0023] Figure 3 Magnetic circuit diagram of bias flux and control flux in an octagonal hybrid radial magnetic bearing.

[0024] Reference numerals

[0025] 1. Rotor assembly; 101. Rotating shaft; 102. Rotor core; 2. Stator assembly; 201. Stator core; 202. Permanent magnet; 2021. First permanent magnet; 2022. Second permanent magnet; 203. Yoke; 204. Magnetic pole; 2041. First magnetic pole; 2042. Second magnetic pole; 205. Air gap; 3. Coil winding; 4. Bias flux; 5. Control flux. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0027] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0028] Example 1

[0029] like Figure 1-Figure 2 As shown, the present invention provides an octagonal hybrid radial magnetic bearing, comprising a rotor assembly 1, a stator assembly 2, and a coil winding 3. The rotor assembly 1 comprises a rotating shaft 101 and a rotor core 102 tightly fitted onto the rotating shaft 101. The rotor core 102 is made of ferromagnetic material and has excellent magnetic conductivity, enabling efficient conduction and concentration of the magnetic field. The tight fitting design of the rotating shaft 101 and the rotor core 102 ensures the stability and rigidity of the rotor assembly 1 during high-speed rotation, reduces deviations caused by vibration and centrifugal force, and improves the smoothness of the overall operation.

[0030] The stator assembly 2 is composed of a stator core 201 and a permanent magnet 202. The stator core 201 includes an octagonal annular yoke 203 and eight magnetic poles 204 pointing from the octagonal vertices to the centroid. The magnetic poles 204 are of equal width, and the permanent magnets 202 are embedded in the eight magnetic poles 204. The width of the octagonal annular yoke 203 is not less than the width of the magnetic poles 204 to ensure that the magnetic flux is more concentrated and efficiently transmitted between the magnetic poles 204. The design of the octagonal structure not only optimizes the distribution of the magnetic field, but also improves the uniformity and stability of the magnetic field by increasing the number of magnetic poles 204. The design of the width relationship between the yoke 203 and the magnetic poles 204 reduces the saturation of the yoke 203 and improves the utilization rate of the magnetic field. The design of the permanent magnet 202 embedded in the magnetic poles 204 provides a stable bias magnetic field and reduces the current demand in the electromagnetic coil.

[0031] Four coil windings 3 are wound around an octagonal annular magnetic yoke 203, with each coil winding 3 spaced two magnetic poles 204 apart, and the coil windings 3 are connected in parallel. The coil windings 3 are wound around the magnetic yoke 203 between two magnetic poles 204 with opposite magnetization directions of the permanent magnet 202. The parallel connection design allows the controller to independently control the magnitude and direction of the current in each coil winding 3, achieving precise control of the rotor assembly 1. The coil windings 3 are wound around the magnetic yoke 203 rather than the magnetic poles 204, effectively solving the problem of insufficient coil winding turns in smaller hybrid radial magnetic bearings and ensuring sufficient electromagnetic force to control the rotor's positional balance.

[0032] A radial air gap 205 is provided between the rotor assembly 1 and the eight magnetic poles 204, allowing the rotor to levitate freely. The presence of the radial air gap 205 ensures the flexibility and stability of the rotor during levitation, reducing wear and heat generation caused by mechanical contact.

[0033] like Figure 3 As shown, the permanent magnet 202 is magnetized radially along the magnetic pole 204, and the magnetization direction is arranged in NNSSNNSS, forming a uniform and stable bias magnetic field, providing a stable radial suspension force for the rotor. The NNSSNNSS arrangement can form a specific magnetic field distribution between the magnetic poles 204, making the bias magnetic field more uniform and stable. This uniformly distributed bias magnetic field helps to further reduce the magnetic flux leakage and magnetic circuit coupling phenomenon, and improve the utilization rate of the magnetic field. The magnetic circuit of the bias flux 4 is: the bias flux 4 starts from the N pole of the first permanent magnet 2021, passes through the first magnetic pole 2041, the radial air gap 205, the rotor core 102, the rotating shaft 101, the second magnetic pole 2042, the second permanent magnet 2022, and finally returns to the S pole of the first permanent magnet 2021 via the magnetic yoke 203.

[0034] The four coil windings 3 are used to control the radial suspension of the rotor assembly 1. The radial suspension control magnetic flux 5 generated after the coil windings 3 are energized has a magnetic path starting from the magnetic yoke 203 and consistent with the magnetic path of the bias magnetic flux 4. When a positive current is passed through the coil windings 3, the control magnetic flux 5 plays a role in enhancing the magnetic field, and the direction of the magnetic path is consistent with the bias magnetic flux 4. When a reverse current is passed through the coil windings 3, the control magnetic flux 5 plays a role in weakening the magnetic field, and the direction of the magnetic path is opposite to that of the bias magnetic flux 4.

[0035] During use, when the rotor assembly 1 is in the equilibrium position, the permanent magnet 202 generates a bias magnetic flux 4 to provide a stable radial suspension force. At this time, no current is passed through the coil winding 3. When the rotor assembly 1 undergoes radial displacement, a forward current is passed through the coil winding 3 in the opposite direction of the displacement, and a reverse current is passed through the coil winding 3 in the same direction of the displacement, generating a control magnetic flux 5. The control magnetic flux 5 and the bias magnetic flux 4 are superimposed and enhanced in the magnetic field at the air gap 205, pulling the rotor back to the equilibrium position.

[0036] In order to concentrate and enhance the magnetic flux, the width of the yoke 203 is not less than the width of the magnetic pole 204; the yoke 203 serves as the main conduction path of the magnetic field, and its width is not less than the width of the magnetic pole 204, which can ensure that the magnetic flux is more concentrated and efficiently transmitted between the magnetic poles 204, reduce magnetic flux leakage, and improve the utilization rate of the magnetic field.

[0037] For ease of control, the four coil windings 3 are connected in parallel. Each coil winding 3 is wound around a yoke 203 between two magnetic poles 204 of a permanent magnet 202 with opposite magnetization directions. The function of the coil winding 3 is to increase or decrease the magnetic flux in a closed magnetic circuit, thereby controlling the magnitude of the magnetic force. Each of the four coil windings 3 controls the magnetic flux in a closed magnetic circuit, and the parallel connection facilitates controller design.

[0038] To meet different usage requirements, the rotor core 102 and the stator core 201 are integrally structured or formed of stacked silicon steel sheets. This allows the design of the rotor core 102 to be determined based on specific application scenarios and requirements to meet different usage requirements. Furthermore, to provide good magnetic conductivity and generate a stronger magnetic field, the rotor core 102 and the stator core 201 are both made of ferromagnetic materials, and the permanent magnets 202 are made of rare earth permanent magnet materials. Ferromagnetic materials have excellent magnetic conductivity and can efficiently conduct and concentrate magnetic fields, while rare earth permanent magnets have extremely high magnetic energy products, meaning they store a large amount of magnetic energy per unit volume, enabling them to generate a stronger magnetic field.

[0039] Therefore, the present invention adopts the above-mentioned octagonal hybrid radial magnetic bearing, and optimizes the magnetic field distribution through the design of octagonal magnetic yoke and equal-width magnetic poles, ensuring the concentration and efficient transmission of magnetic flux. At the same time, the permanent magnet is used to provide bias magnetic flux to reduce the current demand of the electromagnetic coil and reduce heat generation. The coil winding is wound in parallel on the magnetic yoke to solve the problem of insufficient coil turns in small-sized bearings, realize precise control of the rotor assembly, and adapt to high-speed usage scenarios. The overall structure also provides good magnetic conductivity and a stronger magnetic field.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An octagonal hybrid radial magnetic bearing, characterized in that: Including rotor assembly, stator assembly and coil winding, The rotor assembly is composed of a rotating shaft and a rotor core sleeved on the rotating shaft; The stator assembly is composed of a stator core and a permanent magnet. The stator core is composed of an octagonal annular yoke and eight magnetic poles pointing from the octagonal vertices to the centroid. The magnetic poles have the same width and are embedded with permanent magnets. The coil windings are wound on an octagonal annular magnetic yoke, and the coil windings are separated by two magnetic poles; A radial air gap is provided between the rotor assembly and the magnetic poles.

2. The octagonal hybrid radial magnetic bearing according to claim 1, characterized in that: The rotor core and the stator core are both integral structures or silicon steel sheet stacking structures.

3. The octagonal hybrid radial magnetic bearing according to claim 1, characterized in that: The width of the yoke is not less than the width of the magnetic pole.

4. The octagonal hybrid radial magnetic bearing according to claim 1, characterized in that: The permanent magnet is magnetized along the radial direction of the magnetic pole, and the magnetization direction is arranged in NNSSNNSS.

5. The octagonal hybrid radial magnetic bearing according to claim 1, characterized in that: The coil windings are connected in parallel and are wound on a magnetic yoke between two magnetic poles of a permanent magnet with opposite magnetization directions.

6. The octagonal hybrid radial magnetic bearing according to claim 1, characterized in that: The rotor core and the stator core are both made of ferromagnetic materials, and the permanent magnet is made of rare earth permanent magnet material.

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