Double-layer active high-speed magnetic bearings

Abstract

The double-layer active high-speed magnetic levitation bearing disclosed in the present invention belongs to the technical field of magnetic levitation bearings and includes a double stator yoke, wherein the outer ring of the double stator yoke is provided with a plurality of double stator outer teeth, on which outer ring windings are wound, and the inner ring of the double stator yoke is provided with a plurality of double stator inner teeth, on which inner ring windings are wound; the plurality of double stator outer teeth are sleeved with a double bearing outer ring, and the plurality of double stator inner teeth are sleeved with a double bearing inner ring, wherein the double bearing outer ring and the double bearing inner ring are integrally formed into a double bearing inner and outer ring. Based on the single-degree-of-freedom mechanical model of the magnetic levitation bearing, the present invention optimizes the structure of the traditional magnetic levitation bearing and designs a double-layer active high-speed magnetic levitation bearing. By using the double winding, double stator and double bearing inner and outer ring structure, the bearing capacity and stability can be doubled by using only a single active magnetic levitation bearing.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic suspension bearings, and in particular relates to a double-layer active high-speed magnetic suspension bearing. Background Art

[0002] Bearings, as core components in high-end CNC machine tool systems, directly impact machining accuracy and machine tool lifecycles. Traditional bearings have direct contact between mating surfaces, resulting in contact and friction that can cause mechanical wear and reduce the service life of both the machine tool and the bearing system. In recent years, magnetic bearings have garnered significant industry attention. Their key feature is the lack of mechanical contact between mating surfaces, maintaining the rotor's stable levitation through electromagnetic forces generated by permanent magnets or coil current. These bearings offer advantages unmatched by traditional mechanical bearings, including zero friction and wear, long life, no lubrication requirements, and low energy consumption. They hold significant potential for application in high-end equipment manufacturing.

[0003] Magnetic bearings can be divided into active and passive magnetic bearings. Performance indicators for magnetic bearings include load capacity, stiffness, and stability. Active magnetic bearings actively adjust the electromagnetic field through a control system to achieve stable control and dynamic adjustment of the bearing. They are characterized by high precision, high responsiveness, and adjustability. They are suitable for scenarios with high requirements for stability and precision, such as precision instruments and high-speed rotating equipment, and can provide precise axial and radial control. Passive magnetic bearings rely on a fixed magnetic field to produce a magnetic levitation effect, requiring no external control system. They have a simple structure and high reliability, but generally cannot actively adjust the bearing's motion state. They are suitable for general industrial equipment and large machinery, such as centrifugal pumps and wind turbines, and can provide basic axial suspension and support functions.

[0004] Active magnetic bearings offer advantages over passive magnetic bearings, including higher precision and controllability, faster dynamic response, and greater adjustability. With the development of high-end equipment manufacturing, the requirements for the load-bearing capacity and stability of high-speed magnetic bearings have become more stringent. Therefore, the present invention improves the structure of active magnetic bearings to enhance their load-bearing capacity and stability. Summary of the Invention

[0005] The purpose of the present invention is to provide a double-layer active high-speed magnetic suspension bearing, which is beneficial to improving the load-bearing capacity and stability of the active high-speed magnetic suspension bearing.

[0006] The technical solution adopted by the present invention is a double-layer active high-speed magnetic levitation bearing, including a double stator yoke, the outer ring of the double stator yoke is provided with a plurality of double stator outer teeth, the outer ring windings are wound on the double stator outer teeth, the inner ring of the double stator yoke is provided with a plurality of double stator inner teeth, the inner ring windings are wound on the double stator inner teeth; the plurality of double stator outer teeth are sleeved with a double bearing outer ring, the plurality of double stator inner teeth are sleeved with a double bearing inner ring, and the double bearing outer ring and the double bearing inner ring are integrally formed into a double bearing inner and outer ring.

[0007] The present invention is also characterized in that:

[0008] The numbers of the double stator external teeth and the double stator internal teeth are both even numbers, and the ratio of the numbers of the double stator external teeth to the double stator internal teeth is 1.2-1.5:1.

[0009] The slot types between adjacent double stator external teeth and adjacent double stator internal teeth are any one of parallel slot types, skew slot types, wedge slot types and arc slot types.

[0010] The size ratio of the double stator outer teeth, the double stator yoke and the double stator inner teeth is 1.25:0.75:1.

[0011] The pitch ratio of the windings in the outer ring winding and the inner ring winding is 2:1, and the materials of the outer ring winding and the inner ring winding are both single-strand copper core wire.

[0012] The double stator outer teeth, the double stator yokes and the double stator inner teeth are formed by laminating and integrally forming a plurality of stator silicon steel sheets, and the stator silicon steel sheets are high carbon chromium steel.

[0013] A plurality of mounting holes are provided on the double stator yoke, through which stator silicon steel sheet fixing devices are provided. The stator silicon steel sheet fixing devices adopt bolts a, and the material of bolts a is low-carbon chromium bearing steel. Bolts a pass through the mounting holes and are connected to the mounting base, and the material of the mounting base is GCr18Mo; the inner and outer rings of the double bearings are fixed to the side wall of the mounting base in the same direction as the double stator yoke.

[0014] An auxiliary bearing is provided on the other side of the mounting base. The auxiliary bearing is coaxially arranged with the inner ring of the double bearing. The outer ring of the auxiliary bearing is sleeved with an auxiliary bearing cover. The auxiliary bearing cover is fixedly connected to the mounting base through an auxiliary bearing cover fixing device.

[0015] The auxiliary bearing cover fixing device adopts bolt b, and the bolt b is made of low-carbon chromium bearing steel. The outer ring of the auxiliary double bearing is fixed by the bolt b.

[0016] The auxiliary bearing is a mechanical ball bearing; the material of the auxiliary bearing cover is GCr18Mo.

[0017] The beneficial effects of the present invention are:

[0018] This invention achieves double the load capacity and stability using only a single active magnetic bearing, utilizing a dual winding, dual stator, and dual bearing inner and outer ring structures. Furthermore, the integration of independent mechanical auxiliary bearings effectively reduces the overall size of the motor. This invention provides a strong guarantee for the high-speed and stable operation of magnetically levitated electric spindles in high-precision machine tools, improving the precision and efficiency of cutting and milling processes while extending the lifecycle of these high-precision machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the double-layer active high-speed magnetic suspension bearing of the present invention;

[0020] Figure 2 It is a gravitational schematic diagram of the double-layer active high-speed magnetic suspension bearing of the present invention;

[0021] Figure 3 It is a repulsive force schematic diagram of the double-layer active high-speed magnetic suspension bearing of the present invention;

[0022] Figure 4 It is a schematic diagram of the attraction-repulsion type of the double-layer active high-speed magnetic suspension bearing of the present invention;

[0023] Figure 5 This is a schematic diagram of the magnetic flux circuit generated by a single electromagnetic coil in a double-layer active high-speed magnetic bearing of the present invention;

[0024] Figure 6 It is a structural schematic diagram of the double stators in the double-layer active high-speed magnetic suspension bearing of the present invention.

[0025] In the figure, 1. Double bearing inner and outer rings, 101. Double bearing outer ring, 102. Double bearing inner ring, 2. Stator silicon steel sheet, 3. Inner ring winding, 4. Outer ring winding, 5. Stator silicon steel sheet fixing device, 6. Auxiliary bearing cover fixing device, 7. Auxiliary bearing, 8. Auxiliary bearing cover, 9. Mounting base, 10. Double stator yoke, 11. Double stator outer teeth, 12. Double stator inner teeth. DETAILED DESCRIPTION

[0026] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] The double-layer active high-speed magnetic bearing of the present invention can be divided into attraction type, repulsion type and attraction-repulsion type. Through the double stator, double winding and double bearing inner and outer ring 1 structure of the present invention, the inner ring winding 3 and the outer ring winding 4 can generate electromagnetic forces in two directions, and then the inner ring winding 3 and the outer ring winding 4 can generate a pair of electromagnetic forces of equal magnitude and opposite directions, respectively. Figure 2 、 Figure 3 and Figure 4The traditional active magnetic bearings only have two types: attraction type and repulsion type, which is also the difference between the present invention and the prior art.

[0029] like Figure 1 and Figure 6 As shown, the double-layer active high-speed magnetic suspension bearing disclosed in the present invention includes a double stator yoke 10, the outer ring of the double stator yoke 10 is provided with a plurality of double stator outer teeth 11, the outer ring winding 4 is wound on the double stator outer teeth 11, and the outer ring winding 4 of the double winding is passed through a current to generate electromagnetic force, which generates a supporting force on the outer ring 101 of the double bearing, so that the rotor shaft can be stably suspended in the center position; the inner ring of the double stator yoke 10 is provided with a plurality of double stator inner teeth 12, the inner ring winding 3 is wound on the double stator inner teeth 12, and the inner ring winding 3 of the double winding is passed through a current to generate electromagnetic force, which generates a supporting force on the inner ring 102 of the double bearing. The rotor shaft can be stably suspended in the center position; the double stator outer teeth 11, the double stator yoke 10 and the double stator inner teeth 12 are formed by laminating a plurality of stator silicon steel sheets 2 in one piece. The stator silicon steel sheet 2 is the installation position of the double-layer winding, which is mainly the part where the magnetic lines of force pass through and concentrate; a plurality of double stator outer teeth 11 are sleeved with double bearing outer rings 101, and a plurality of double stator inner teeth 12 are sleeved with double bearing inner rings 102. The double bearing outer rings 101 and the double bearing inner rings 102 are integrally formed into double bearing inner and outer rings 1. The double bearing inner and outer rings 1 carry the rotor shaft of the motor and are the components that are in direct contact with the rotor shaft of the motor; the double shaft The inner and outer rings 1 of the bearing are in direct contact with the motor rotor and are the objects of electromagnetic force. When the inner ring winding 3 in the double winding and the outer ring winding 4 in the double winding are connected to the current, electromagnetic force is generated to support the inner and outer rings 1 of the double bearing. The stator silicon steel sheet 2 is fixed to the mounting base 9 by the stator silicon steel sheet fixing device 5. The stator silicon steel sheet fixing device 5 firmly fixes the stator silicon steel sheet 2 to the mounting base 9 to ensure that the stator silicon steel sheet 2 will not move up, down, left or right. The stator silicon steel sheet fixing device 5 uses a cylindrical bolt with a diameter of 3mm and a length of 80mm. The material of the cylindrical bolt is low-carbon chromium bearing steel G Cr9; An auxiliary bearing 7 is provided on the other side of the mounting base 9. The rotor shaft is supported by the auxiliary bearing 7 when stationary. When the rotor shaft deviates up, down, left, or right, the auxiliary bearing 7 ensures that the rotor shaft does not deviate, while also ensuring the safety of the rotor shaft during high-speed operation. The auxiliary bearing 7 secures the motor rotor to prevent it from colliding with the stator teeth during startup and shutdown, potentially damaging the motor. The auxiliary bearing 7 is coaxially arranged with the dual-bearing inner ring 102. The outer ring of the auxiliary bearing 7 is fitted with an auxiliary bearing cap 8, which secures the auxiliary bearing 7 and ensures that the auxiliary bearing 7 is installed in an accurate and appropriate position. The auxiliary bearing cap 8 is fixedly connected to the mounting base 9 by an auxiliary bearing cap fixing device 6. The auxiliary bearing cap fixing device 6 enables the auxiliary bearing cap 8 to secure the auxiliary bearing 7 to the mounting base 9, allowing the auxiliary bearing 7 to secure the rotor shaft within the allowable deviation range.

[0030] This embodiment provides a double stator structure, further provides a double stator winding and a double bearing inner and outer ring 1 structure, which can achieve twice the load-bearing capacity and stability of a common active magnetic bearing of the same size, achieving better performance; combined with Figure 3 As shown, the principle of this embodiment is that after the inner ring winding 3 and the outer ring winding 4 are powered on, they can generate a pair of opposite electromagnetic forces on the dual-bearing inner ring 102 and the dual-bearing outer ring 101. The pair of opposite electromagnetic forces are an electromagnetic repulsion force directed toward the dual-bearing inner ring 102 and an electromagnetic repulsion force directed toward the dual-bearing outer ring 101. Through this pair of electromagnetic repulsion forces of equal magnitude and opposite directions, stable suspension of the dual bearings is achieved.

[0031] Specifically, a plurality of double stator outer teeth 11 and a double stator yoke 10 constitute an outer stator, and a double stator inner teeth 12 and a double stator yoke 10 constitute an inner stator.

[0032] In a specific embodiment, the outer ring outer diameter of the dual bearing inner and outer rings 1 is 320 mm, the outer ring inner diameter is 302 mm, the inner ring outer diameter is 58 mm, the inner ring inner diameter is 40 mm, and the material is high carbon chromium bearing steel GCr15.

[0033] Example 2

[0034] On the basis of Example 1, the number of the double stator external teeth 11 and the double stator internal teeth 12 of the present invention are both even numbers, and the ratio of the number of the double stator external teeth 11 to the double stator internal teeth 12 is 1.2-1.5:1.

[0035] Specifically, the number of double stator outer teeth 11 and double stator inner teeth 12 is an "even pair", such as 4-6, 6-8 and 8-12, in order to ensure stable suspension in two degrees of freedom. The number of double stator inner teeth 12 is usually less than the number of double stator outer teeth 11, because the outer stator is larger in size and needs to generate a larger electromagnetic force to ensure stable suspension of the outer rotor.

[0036] In this embodiment, the number of the dual stator internal teeth 12 is 6-8.

[0037] Furthermore, the groove types between adjacent double stator external teeth 11 and adjacent double stator internal teeth 12 are any one of parallel groove types, oblique groove types, wedge-shaped groove types and arc groove types.

[0038] Specifically, the slot profiles of adjacent dual stator external teeth 11 and adjacent dual stator internal teeth 12 can be consistent or different, depending on the application scenario and power requirements, as well as a comprehensive consideration of factors such as manufacturing cost, performance, stability, and maintenance. In this embodiment, the stator slot profiles include the following four types: 1. Parallel slot profile. Advantages: Simple, easy to wind, suitable for low-cost applications, and widely used in low-power, low-cost bearings. Disadvantages: Can easily cause magnetic field fluctuations, resulting in less stable bearing operation, especially at low speeds and high loads, which may cause vibration and noise. 2. Skewed slot profile. Advantages: Reduces magnetic field fluctuations, improves bearing operation stability, and reduces harmonic content compared to the parallel slot profile. Disadvantages: Relatively complex manufacturing and winding, resulting in higher costs. 3. Wedge slot profile. Advantages: Improves bearing operation stability and reduces harmonic content, and is commonly used in medium-power and medium-high-speed bearings. Disadvantages: Relatively complex manufacturing and winding, resulting in higher costs, but offers better performance than the skewed slot profile. 4. Circular arc slot profile. Advantages: Effectively reduces magnetic field fluctuations, improves the running stability of bearings, and is used in some high-performance motors and special applications; Disadvantages: Difficult to manufacture and wind, and high cost.

[0039] Based on modeling and simulation using SOLIDWORKS and ANSYS MAXWELL, in this embodiment, the slot type between adjacent double stator external teeth 11 and adjacent double stator internal teeth 12 is selected as a skew slot type, which can reduce magnetic field fluctuations, improve the running smoothness of the bearing, and reduce harmonic components compared to parallel slot types.

[0040] Furthermore, the size ratio of the double stator outer teeth 11 , the double stator yoke 10 , and the double stator inner teeth 12 is 1.25:0.75:1.

[0041] Specifically, the double stator outer teeth 11 need to install more windings to generate greater electromagnetic force to ensure the stable suspension of the outer rotor. Therefore, the size of the double stator inner teeth 12 is smaller than the size of the double stator outer teeth 11. It should be noted that the size here can be considered to refer to the actual material volume in actual design.

[0042] In this embodiment, the length of the double stator inner teeth 12 is 40 mm, the tooth width is 25 mm, the tooth thickness is 60 mm, the outer diameter is 155 mm, and the inner diameter is 140 mm; the length of the double stator outer teeth 11 is 50 mm, the tooth width is 35 mm, the tooth thickness is 60 mm, the outer diameter is 300 mm, and the inner diameter is 235 mm; the thickness of the double stator yoke 10 is 30 mm, the outer diameter is 250 mm, and the inner diameter is 220 mm.

[0043] Furthermore, the pitch ratio of the windings in the outer ring winding 4 and the inner ring winding 3 is 2:1, and the materials of the outer ring winding 4 and the inner ring winding 3 are both single-strand copper core wire.

[0044] The inner winding 3 adopts double-layer parallel winding, 30 turns, and a winding pitch of 2.

[0045] The outer coil winding 4 adopts double-layer parallel winding, 30 turns, and a winding pitch of 4.

[0046] Among them, distributed winding has better symmetry, which can reduce the impact of stator slots on the magnetic field, thereby reducing the harmonic loss and noise of the bearing and improving its operating efficiency and stability; compared with concentrated winding, distributed winding has a more uniform magnetic flux distribution, so it has better thermal stability and anti-corona ability; distributed winding is more common in high-power and high-speed occasions, which can reduce bearing loss and extend its service life.

[0047] Parallel windings offer the following advantages: 1. Increased bearing power and output: By connecting windings in parallel, the total current capacity of the bearing is increased, thereby improving the bearing's power output. This is particularly useful in applications requiring higher power. 2. Reduced winding current density: Parallel windings divide the current, reducing the current carried by each winding and lowering the current density. This reduces bearing winding temperature rise and extends winding life. 3. Improved bearing efficiency: Because parallel windings reduce the current density of each winding, winding losses are reduced, thereby improving motor efficiency. This means that for the same input power, the bearing can achieve higher power output and more efficient energy utilization. 4. Improved system stability and reliability: Parallel windings provide redundancy during bearing operation. Even if one winding fails, the other parallel windings can still maintain motor operation, improving system stability and reliability. 5. Reduced bearing electromagnetic noise and vibration: By connecting windings in parallel, the current carried by each winding is reduced, thereby reducing electromagnetic forces and vibration within the bearing. This helps reduce electromagnetic noise and vibration levels generated by the bearing, improving equipment operating comfort.

[0048] Both inner and outer windings 3 and 4 utilize distributed, full-pitch windings with integer slots. The windings are connected in parallel but at different pitches. This difference in pitch is primarily for the stability of the new dual-layer active magnetic bearing. The different sizes of the bearing stator's inner and outer rings also constrain the choice of winding pitch.

[0049] Example 3

[0050] On the basis of Example 1, the stator silicon steel sheet 2 in the present invention is high carbon chromium steel.

[0051] Based on the above structure, the stator silicon steel sheet 2 in this embodiment has six stator slots in the inner layer and eight stator slots in the outer layer. The dimensions of the inner and outer stator slots are as follows: slot width BS0 = 20 mm, slot height hs0 = 7 mm, total slot depth hs = 50 mm, and the material is high carbon chromium steel AISI 52100.

[0052] Furthermore, a plurality of mounting holes are formed on the double stator yoke 10 , and the stator silicon steel sheet fixing device 5 uses bolts a made of low-carbon chromium bearing steel. The bolts a pass through the mounting holes and are connected to the mounting base 9 .

[0053] Furthermore, the auxiliary bearing cover fixing device 6 uses a cylindrical bolt b with a diameter of 3 mm and a length of 40 mm, and the material is low-carbon chromium bearing steel, and the auxiliary dual bearing outer ring 101 is fixed by the bolt b.

[0054] Furthermore, the auxiliary bearing 7 is a mechanical ball bearing; the material of the auxiliary bearing cover 8 is GCr18Mo.

[0055] In the embodiment, the auxiliary bearing 7 is a national standard mechanical ball bearing with an outer diameter of 50 mm, an inner diameter of 30 mm, and a thickness of 20 mm.

[0056] Furthermore, the auxiliary bearing cap 8 and the mounting base 9 are both made of GCr18Mo. The auxiliary bearing cap 8 is made of a cubic GCr18Mo steel block with a thickness of 20 mm and a width of 60 mm, and the mounting base 9 is made of a cubic GCr18Mo steel block with a thickness of 20 mm and a width of 400 mm.

[0057] The theoretical basis for the levitation force generated by magnetic bearings is to analyze the magnetic flux loop generated by a single electromagnetic coil. The specific analysis process is as follows: Figure 5 As shown, A1, A2, and A3 correspond to the cross-sectional area of ​​the magnetic circuit of the coil core, the rotor core, and the magnetic pole. F corresponds to the electromagnetic force, and Φ is the magnetic flux. Analyzing the magnetic flux loop of a single electromagnetic coil, based on the principle of electromagnetic induction and referring to the ideas of magnetic circuit analysis in relevant books, ignoring tiny leakage magnetic flux, we can obtain the Maxwell attractive force generated by the electromagnetic coil as:

[0058]

[0059] In formula (1), μ0 is the magnetic permeability of air; N0 is the number of turns of the coil winding of the magnetic bearing, i is the coil current, x is the actual distance from the magnetic pole to the shaft surface, and K is the electromagnetic force coefficient.

[0060] It can be seen that the electromagnetic force is proportional to the square of the current and inversely proportional to the square of the displacement. By controlling the current, the displacement can be controlled, thereby keeping the magnetic bearing in a stable suspension state.

[0061] The embodiment of the present invention is a distributed full-pitch winding parallel tooth 6-8 double-layer active high-speed magnetic levitation bearing. Based on the premise that the effective value of the control current is I=10A, the bearing air gap length is δ=0.55mm, the number of winding turns is 30 turns, and the number of parallel branches is 2 and 4 respectively, the comparative results of the bearing capacity and stability of the double-layer active high-speed magnetic levitation bearing of the present invention are obtained as shown in Table 1.

[0062] Table 1

[0063]

Claims

1. Double-layer active high-speed magnetic bearing, characterized in that: The invention comprises a double stator yoke (10), wherein the outer ring of the double stator yoke (10) is provided with a plurality of double stator outer teeth (11), and the outer ring winding (4) is wound on the double stator outer teeth (11); the inner ring of the double stator yoke (10) is provided with a plurality of double stator inner teeth (12), and the inner ring winding (3) is wound on the double stator inner teeth (12); the plurality of double stator outer teeth (11) are provided with a double bearing outer ring (101), and the plurality of double stator inner teeth (12) are provided with a double bearing inner ring (102); the double bearing outer ring (101) and the double bearing inner ring (102) are integrally formed into a double bearing inner and outer ring (1); The size ratio of the double stator outer teeth (11), the double stator yoke (10), and the double stator inner teeth (12) is 1.25:0.75:1; The inner winding (3) is a double-layer parallel winding with 30 turns and a winding pitch of 2; The outer coil winding (4) is a double-layer parallel winding with 30 turns and a winding pitch of 4; The number of the double stator external teeth (11) and the double stator internal teeth (12) are both even numbers, and the ratio of the number of the double stator external teeth (11) to the double stator internal teeth (12) is 1.2-1.5:

1.

2. The double-layer active high-speed magnetic bearing according to claim 1, characterized in that: The groove types between the adjacent double stator external teeth (11) and the adjacent double stator internal teeth (12) are any one of a parallel groove type, an oblique groove type, a wedge groove type and an arc groove type.

3. The double-layer active high-speed magnetic bearing according to claim 2, characterized in that: The pitch ratio of the windings in the outer ring winding (4) and the inner ring winding (3) is 2:1, and the materials of the outer ring winding (4) and the inner ring winding (3) are both single-strand copper core wire.

4. The double-layer active high-speed magnetic bearing according to claim 1, characterized in that: The double stator outer teeth (11), the double stator yoke (10) and the double stator inner teeth (12) are formed by laminating and integrally forming a plurality of stator silicon steel sheets (2), wherein the stator silicon steel sheets (2) are high-carbon chromium steel.

5. The double-layer active high-speed magnetic bearing according to claim 4, characterized in that: The double stator yoke (10) is provided with a plurality of mounting holes, wherein the mounting holes are penetrated by stator silicon steel sheet fixing devices (5), wherein the stator silicon steel sheet fixing devices (5) are bolts a, wherein the material of the bolts a is low-carbon chromium bearing steel, wherein the bolts a pass through the mounting holes and are connected to a mounting base (9), wherein the material of the mounting base (9) is GCr18Mo; the inner and outer rings (1) of the double bearings are fixed to the side wall of the mounting base (9) in the same direction as the double stator yoke (10).

6. The double-layer active high-speed magnetic bearing according to claim 5, characterized in that: An auxiliary bearing (7) is provided on the other side of the mounting base (9), the auxiliary bearing (7) and the inner ring (102) of the double bearing are coaxially arranged, the outer ring of the auxiliary bearing (7) is sleeved with an auxiliary bearing cover (8), and the auxiliary bearing cover (8) and the mounting base (9) are fixedly connected via an auxiliary bearing cover fixing device (6).

7. The double-layer active high-speed magnetic bearing according to claim 6, characterized in that: The auxiliary bearing cover fixing device (6) uses bolts b, which are made of low-carbon chromium bearing steel, and the auxiliary double bearing outer ring (101) is fixed by the bolts b.

8. The double-layer active high-speed magnetic bearing according to claim 6, characterized in that: The auxiliary bearing (7) is a mechanical ball bearing; the material of the auxiliary bearing cover (8) is GCr18Mo.

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