Octagonal mixed radial magnetic bearing

Abstract

The utility model provides an octagonal mixed radial magnetic bearing, which belongs to the technical field of magnetic suspension bearings, and 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 sleeved on 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. By adopting the octagonal mixed radial magnetic bearing, the problem that the number of winding turns of the coil is insufficient when the size of the existing mixed radial magnetic bearing is small is solved.

Description

Technical Field

[0001] This utility model relates to the field of magnetic levitation bearing technology, and in particular to an octagonal hybrid radial magnetic bearing. Background Technology

[0002] In the field of magnetic levitation bearing technology, based on the different sources of magnetic force, magnetic levitation bearings are mainly divided into three types: permanent magnet bearings, electromagnetic bearings, and permanent magnet bias bearings. Permanent magnet bearings rely on the attraction and repulsion between permanent magnet rings to achieve stable rotor levitation. However, due to the inherent characteristics of permanent magnet materials, permanent magnet bearings are difficult to adapt to high-speed applications and cannot achieve active control functions. Electromagnetic bearings, on the other hand, use electromagnetic coils to provide electromagnetic force to maintain stable rotor levitation. However, electromagnetic coils generate a large amount of heat after being energized for a long time, which not only affects the operating efficiency of the equipment but may also adversely affect its stability and lifespan.

[0003] To overcome the limitations of single-type magnetic levitation bearings, hybrid magnetic bearings have emerged. Hybrid magnetic bearings combine the advantages of permanent magnet bearings and electromagnetic bearings. They utilize permanent magnets to provide a static bias magnetic field, replacing the static bias magnetic field of the electromagnetic windings in electromagnetic bearings. Simultaneously, a control magnetic field is generated by an electromagnetic coil to adjust the rotor's levitation position. However, existing hybrid radial magnetic levitation bearings have diverse structures, and most designs wind the control winding around the magnetic poles. Due to limitations in the shape of the coil cavity, this design may result in insufficient turns on the coil when the hybrid radial magnetic bearing is small, making it difficult to generate sufficient electromagnetic force to control the rotor's positional balance, thus affecting the overall performance and stability of the magnetic bearing.

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

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

[0006] To achieve the above objectives, this utility model provides an octagonal hybrid radial magnetic bearing, comprising a rotor assembly, a stator assembly, and coil windings.

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

[0008] The stator assembly consists of a stator core and permanent magnets. The stator core consists of an octagonal annular magnetic yoke and eight magnetic poles pointing from the vertices of the octagon to the centroid. The magnetic poles have the same width, and permanent magnets are embedded in the magnetic poles.

[0009] The coil windings are wound around 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 pole.

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

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

[0013] Preferably, the permanent magnet is magnetized radially along the magnetic poles, and the magnetization direction is arranged in the order 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 stator core are both made of ferromagnetic materials, and the permanent magnet is made of rare earth permanent magnet material.

[0016] Therefore, the present invention employs the aforementioned 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 winding it on the magnetic pole, the problem of insufficient coil turns in small-sized hybrid radial magnetic bearings is effectively solved, thereby generating sufficient electromagnetic force to control the rotor's positional balance.

[0018] 2. Reduce the current demand of the electromagnetic coil: By using permanent magnets embedded in the magnetic poles to provide bias flux, the current demand of the electromagnetic coil is reduced, thereby reducing the heat generated by the electromagnetic coil being energized for a long time and improving the operating efficiency and stability of the equipment.

[0019] 3. The permanent magnet is magnetized radially along the magnetic poles, and the magnetization direction is arranged in a specific manner, which can form a more uniform and stable bias magnetic field between the magnetic poles, further reducing magnetic flux leakage and magnetic circuit coupling, 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 magnitude and direction in each coil winding can be controlled independently, thereby precisely adjusting the magnetic field strength generated by each winding and achieving precise control of the rotor assembly. Attached Figure Description

[0021] Figure 1 A schematic diagram of an octagonal hybrid radial magnetic bearing;

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

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

[0024] Figure Labels

[0025] 1. Rotor assembly; 101. 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 Implementation

[0026] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.

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

[0028] Example 1

[0029] like Figures 1-2 As shown, this utility model provides an octagonal hybrid radial magnetic bearing, including a rotor assembly 1, a stator assembly 2, and a coil winding 3. The rotor assembly 1 consists of a shaft 101 and a rotor core 102 tightly fitted onto the shaft 101. The rotor core 102 is made of ferromagnetic material and has excellent magnetic permeability, enabling efficient conduction and concentration of the magnetic field. The tight fitting design between the shaft 101 and the rotor core 102 ensures the stability and rigidity of the rotor assembly 1 during high-speed rotation, reduces misalignment caused by vibration and centrifugal force, and improves the overall smoothness of operation.

[0030] Stator assembly 2 consists of a stator core 201 and permanent magnets 202. The stator core 201 includes an octagonal annular yoke 203 and eight magnetic poles 204 extending from the vertices of the octagon to its centroid. The magnetic poles 204 are of equal width, and the permanent magnets 202 are embedded within 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 magnetic flux is more concentrated and efficiently transferred between the magnetic poles 204. The octagonal structure design not only optimizes the magnetic field distribution but also improves the uniformity and stability of the magnetic field by increasing the number of magnetic poles 204. The width relationship between the yoke 203 and the magnetic poles 204 reduces yoke saturation and improves magnetic field utilization. The design of the permanent magnets 202 embedded within the magnetic poles 204 provides a stable bias magnetic field, reducing the current demand in the electromagnetic coils.

[0031] Four coil windings 3 are wound on 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 on 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 fact that the coil windings 3 are wound on the magnetic yoke 203 rather than on the magnetic poles 204 effectively solves the problem of insufficient coil turns in small-sized hybrid radial magnetic bearings, 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, and reduces wear and heat generation caused by mechanical contact.

[0033] like Figure 3 As shown, permanent magnet 202 is radially magnetized along magnetic pole 204, with the magnetization direction arranged in the NNSSNNSS pattern, forming a uniform and stable bias magnetic field to provide a stable radial levitation force for the rotor. The NNSSNNSS arrangement can form a specific magnetic field distribution between magnetic poles 204, making the bias magnetic field more uniform and stable. This uniformly distributed bias magnetic field helps to further reduce magnetic flux leakage and magnetic circuit coupling, and improve the utilization rate of the magnetic field. The magnetic circuit of the bias magnetic flux 4 is as follows: the bias magnetic 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 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 yoke 203.

[0034] Four coil windings 3 are used to control the radial levitation of rotor assembly 1. The radial levitation control flux 5 generated after the coil windings 3 are energized has a magnetic path starting from the yoke 203 and is consistent with the magnetic path of the bias flux 4. When a positive current is passed through the coil windings 3, the control flux 5 enhances the magnetic field and the magnetic path direction is consistent with the bias flux 4. When a reverse current is passed through the coil windings 3, the control flux 5 weakens the magnetic field and the magnetic path direction is opposite to the bias flux 4.

[0035] When in use, the rotor assembly 1 is in the equilibrium position and the permanent magnet 202 generates a bias flux 4 to provide a stable radial levitation force. At this time, no current is passed through the coil winding 3. When the rotor assembly 1 is radially deflected, the coil winding 3 in the opposite direction of the deflection is passed through a positive current, and the coil winding 3 in the same direction of the deflection is passed through a reverse current, generating a control flux 5. The control flux 5 and the bias flux 4 are superimposed and enhanced 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 magnetic yoke 203 is not less than the width of the magnetic pole 204. As the main conduction path of the magnetic field, the width of the magnetic yoke 203 is not less than the width of the magnetic pole 204, which can ensure that the magnetic flux is transmitted more concentratedly and efficiently 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. The coil windings 3 are wound around the yoke 203 between the two magnetic poles 204 of the permanent magnet 202 with opposite magnetization directions. The function of the coil windings 3 is to increase or decrease the magnetic flux in a closed magnetic circuit, thereby controlling the magnitude of the magnetic force. The four coil windings 3 each control the magnetic flux in a closed magnetic circuit, and the parallel connection facilitates controller design.

[0038] To meet diverse application requirements, the rotor core 102 and stator core 201 are either integral structures or composed of stacked silicon steel sheets. This allows the design of the rotor core 102 to be tailored to specific application scenarios and needs. Furthermore, to provide excellent magnetic conductivity and generate a stronger magnetic field, both the rotor core 102 and stator core 201 are made of ferromagnetic materials, while the permanent magnet 202 is made of rare-earth permanent magnet materials. Ferromagnetic materials possess excellent magnetic conductivity, enabling efficient conduction and concentration of magnetic fields, while rare-earth permanent magnet materials have extremely high energy products, meaning they store a large amount of magnetic energy per unit volume, thus generating a stronger magnetic field.

[0039] Therefore, this utility model adopts the above-mentioned octagonal hybrid radial magnetic bearing. The magnetic field distribution is optimized by the design of the octagonal magnetic yoke and the equal-width magnetic poles, which ensures the concentration and efficient transmission of magnetic flux. At the same time, the use of permanent magnets to provide bias magnetic flux reduces the current demand of electromagnetic coils and reduces heat generation. The parallel winding of the coils on the magnetic yoke solves the problem of insufficient number of turns of small-sized bearing coils, realizes precise control of rotor assembly, and adapts to high-speed application scenarios. The overall structure also provides good magnetic permeability and a stronger magnetic field.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solution of this utility model, and these modifications or equivalent substitutions cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of this utility model.

Claims

1. An octagonal hybrid radial magnetic bearing characterized by, Includes rotor assembly, stator assembly, and coil windings. The rotor assembly consists of a rotating shaft and a rotor core sleeved on the rotating shaft; The stator assembly consists of a stator core and permanent magnets. The stator core consists of an octagonal annular magnetic yoke and eight magnetic poles pointing from the vertices of the octagon to the centroid. The magnetic poles have the same width, and permanent magnets are embedded in the magnetic poles. The coil windings are wound around 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 pole.

2. The octagonal hybrid radial magnetic bearing of claim 1, wherein, Both the rotor core and stator core are integral structures or stacked silicon steel sheet structures.

3. The octagonal hybrid radial magnetic bearing of claim 1, wherein, The width of the magnetic yoke is not less than the width of the magnetic pole.

4. The octagonal hybrid radial magnetic bearing of claim 1, wherein, The permanent magnet is magnetized radially along the magnetic poles, and the magnetization direction is arranged in the order NNSSNNSS.

5. The octagonal hybrid radial magnetic bearing of claim 1 wherein, The coil windings are connected in parallel and are wound around a yoke between two magnetic poles of a permanent magnet that are magnetized in opposite directions.

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

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