Hybrid magnetic bearing and method of assembling the same, electric machine

Abstract

This invention provides a hybrid magnetic levitation bearing, its assembly method, and a motor. The hybrid magnetic levitation bearing includes: a housing; an axial magnetic bearing assembly comprising an inner magnetic ring, an outer magnetic ring, an axial permanent magnet ring, and an axial control winding, wherein the outer magnetic ring, the axial permanent magnet ring, and the inner magnetic ring are sequentially fitted from the outside to the inside along the radial direction of the inner magnetic ring; a front radial magnetic bearing assembly and a rear radial magnetic bearing assembly connected to opposite ends of the axial magnetic bearing assembly; a shaft; and a radial permanent magnet ring capable of providing a permanent magnet bias magnetic field for the axial magnetic bearing assembly, the front radial magnetic bearing assembly, and the rear radial magnetic bearing assembly. This invention adds an axial permanent magnet ring within the axial magnetic bearing assembly, increasing the bias magnetic field at the axial air gap. This improves the ultimate load output of the axial magnetic bearing assembly without increasing the volume of the permanent magnet or reducing the axial air gap, thereby increasing the axial stiffness of the bearing and reducing the manufacturing cost of the magnetic levitation bearing.

Description

Technical Field

[0001] This invention belongs to the field of motor design technology, specifically relating to a hybrid magnetic levitation bearing and its assembly method, and a motor. Background Technology

[0002] Magnetic levitation bearings possess a series of excellent qualities, including non-contact operation, wear-free operation, high speed, high precision, and no need for lubrication or sealing. They are a high-tech product integrating electromagnetics, electronic technology, control engineering, signal processing, and mechanics.

[0003] Magnetic bearings are classified into three types: active, passive, and hybrid. Active magnetic bearings have high stiffness and can be precisely controlled, but require a large volume and consume a lot of power to generate a unit load capacity. Passive magnetic bearings use the attraction or repulsion between magnetic materials to levitate the rotor, resulting in relatively low stiffness and damping. Hybrid magnetic bearings use permanent magnets to provide a bias magnetic field, replacing the static bias magnetic field generated by electromagnets in active magnetic bearings. This reduces the ampere-turns of the control windings, shrinks the bearing size, and increases the bearing's load capacity. Hybrid magnetic bearings have irreplaceable advantages in fields with strict requirements on size and power consumption, and are mainly used in high-speed and ultra-high-speed applications. Therefore, the integration and miniaturization of magnetic levitation systems, as well as improving the stability and reliability of control systems, will be key research directions.

[0004] To achieve contactless support for the rotor, a magnetic levitation bearing system requires control over its five degrees of freedom in space. Traditional magnetic levitation structures utilize methods such as... Figure 1 As shown, the permanent magnet biased radial bearings before and after the permanent magnet biased radial bearings control the radial four-degree-of-freedom suspension of the rotor shaft, while the permanent magnet biased axial bearing controls the axial degree-of-freedom suspension of the rotor shaft. Two sets of permanent magnet biased radial electromagnetic bearings and one set of permanent magnet biased axial bearings achieve five-degree-of-freedom suspension in the rotor space. Figure 2 and Figure 3 The diagram illustrates the working principle of a permanent magnet bias radial bearing. The permanent magnet generates a bias magnetic field, which, through the auxiliary stator poles, the shaft, and the radial stator poles, forms a closed loop, creating a permanent magnet bias magnetic field. This bias magnetic flux is formed in the main air gap between the radial stator poles and the shaft. Control current is applied to the radial horizontal and radial vertical control windings to generate a control magnetic field. This field, passing through the stator core and shaft, adjusts the bias magnetic flux between the radial stator poles and the main air gap, achieving radial two-degree-of-freedom levitation control. Figure 4The diagram illustrates the working principle of an axial magnetic levitation bearing. A permanent magnet generates a bias magnetic field, which forms a closed loop through the stator cores and thrust disk at both ends, creating a bias magnetic field. This bias magnetic flux is generated in the air gap between the left and right stator cores and the thrust disk. A control current is applied to the control winding to form a control magnetic field, which, through the stator cores and thrust disk, forms a closed loop, constituting the control magnetic circuit. Adjusting the bias magnetic flux in the stator cores and thrust disk at both ends achieves axial levitation control of the rotor shaft. Each set of radial magnetic levitation bearings controls two radial degrees of freedom of the rotor, while the axial magnetic levitation bearing controls the axial translational degree of freedom of the rotor. The magnetic levitation system has three drawbacks: ① The radial and axial control systems are arranged in parallel, which increases the rotor length, causes large rotor deflection, low natural frequency, and low rotor limiting speed; ② The independent axial control system requires a separate axial thrust bearing, making the rotor structure complex; ③ The permanent magnet generates a bias magnetic field through the radial and axial air gaps. Generally, the axial air gap is larger, and the bias magnetic field at the axial air gap is smaller, which limits the ultimate load output of the axial bearing. If the ultimate output of the axial bearing needs to be increased, the volume of the permanent magnet needs to be increased or the axial air gap needs to be reduced, thereby increasing the product cost of the magnetic levitation system. Summary of the Invention

[0005] Therefore, the present invention provides a hybrid magnetic levitation bearing and its assembly method, as well as a motor, which can solve the technical problem that the bias magnetic field at the axial air gap in the prior art is small, resulting in a small ultimate load output of the axial magnetic bearing assembly.

[0006] To address the above problems, the present invention provides a hybrid magnetic levitation bearing, comprising:

[0007] A housing having a magnetic bearing accommodating space;

[0008] An axial magnetic bearing assembly, connected within the magnetic bearing housing space, includes an inner magnetic ring, an outer magnetic ring, an axial permanent magnet ring, and an axial control winding. The outer magnetic ring, the axial permanent magnet ring, and the inner magnetic ring are sequentially fitted from the outside to the inside along the radial direction of the inner magnetic ring.

[0009] The front radial magnetic bearing assembly and the rear radial magnetic bearing assembly are connected to the opposite ends of the axial magnetic bearing assembly;

[0010] The rotating shaft is intermittently inserted into the central through hole of the inner magnetic ring;

[0011] The radial permanent magnet ring can provide a permanent magnet bias magnetic field for the axial magnetic bearing assembly, the front radial magnetic bearing assembly and the rear radial magnetic bearing assembly.

[0012] In some implementations...

[0013] The shaft has two thrust bearings, which are spaced apart along the axial direction of the shaft. The axial magnetic bearing assembly is at least partially located in the gap space between the two thrust bearings.

[0014] In some implementations...

[0015] The inner magnetic ring and the outer magnetic ring protrude from the two end faces of the axial permanent magnet ring and form two annular grooves with openings facing one side of the corresponding thrust portion. The axial control winding has two sets, and each set of the axial control winding is wound in the respective annular groove.

[0016] In some implementations...

[0017] The axial control winding is encapsulated and assembled within the annular groove; and / or...

[0018] The axial control winding is bolted into the annular groove.

[0019] In some implementations...

[0020] The thrust section is heat-fitted and connected to the rotating shaft.

[0021] In some implementations...

[0022] The radial permanent magnet ring is fitted between the outer magnetic ring and the housing, and is clamped between the front radial magnetic bearing assembly and the rear radial magnetic bearing assembly.

[0023] In some implementations...

[0024] The front radial magnetic bearing assembly includes a front radial stator core and a front radial control winding wound on each magnetic pole tooth of the front radial stator core. The rear radial magnetic bearing assembly includes a rear radial stator core and a rear radial control winding wound on each magnetic pole tooth of the rear radial stator core. A front radial air gap is formed between each magnetic pole tooth of the front radial stator core and one of the thrust portions. A rear radial air gap is formed between each magnetic pole tooth of the rear radial stator core and the other thrust portion. The radial permanent magnet ring is clamped between the front radial stator core and the rear radial stator core.

[0025] In some implementations...

[0026] The housing is formed by assembling a front housing and a rear housing. The inner wall of the front housing has a front positioning flange, and the inner wall of the rear housing has a rear positioning flange. The radial permanent magnet ring is clamped between the front positioning flange and the rear positioning flange.

[0027] In some implementations...

[0028] One end of the inner ring wall of the radial permanent magnet ring has a first axial positioning protrusion; and / or,

[0029] One end of the inner ring wall of the outer magnetic ring has a second axial positioning protrusion.

[0030] In some implementations...

[0031] The outer magnetic ring, axial permanent magnet ring, and inner magnetic ring are thermally fitted together as a single unit.

[0032] The present invention also provides an assembly method for the hybrid magnetic levitation bearing as described above, comprising the following steps:

[0033] The outer magnetic ring, the axial permanent magnet ring, and the inner magnetic ring are sequentially assembled from the outside to the inside along the radial direction of the inner magnetic ring to form the axial magnetic bearing assembly, and the radial permanent magnet ring is fitted on the outside of the axial magnetic bearing assembly.

[0034] The front radial magnetic bearing assembly is assembled inside the front housing, and the rear radial magnetic bearing assembly is assembled inside the rear housing;

[0035] The front housing, which is assembled with the front radial magnetic bearing assembly, and the rear housing, which is assembled with the rear radial magnetic bearing assembly, are respectively assembled close to each other from both ends of the axial magnetic bearing assembly, and the radial permanent magnet ring is placed within the magnetic bearing accommodating space of the housing.

[0036] The rotating shaft is inserted into the central through hole of the inner magnetic ring.

[0037] In some implementations...

[0038] The rotating shaft has two thrust bearings, and each thrust bearing is fitted onto both ends of the rotating shaft, with the positions corresponding to the front radial magnetic bearing assembly and the rear radial magnetic bearing assembly, respectively.

[0039] The present invention also provides an electric motor, including the above-described hybrid magnetic levitation bearing.

[0040] This invention provides a hybrid magnetic levitation bearing, its assembly method, and a motor. On one hand, the axial magnetic bearing assembly forms an integrated structure between the front and rear radial magnetic bearing assemblies, making the structure of the hybrid magnetic levitation bearing simpler and more compact, and occupying less shaft length space. This results in a smaller overall shaft length, which helps reduce rotor deflection, increases the rotor's limiting speed, and lowers its natural frequency. On the other hand, in this invention, while the radial permanent magnet ring provides radial and axial permanent magnet bias magnetic fields, an axial permanent magnet ring is added inside the axial magnetic bearing assembly. This increases the bias magnetic field at the axial air gap, thereby increasing the ultimate load output of the axial magnetic bearing assembly without increasing the volume of the permanent magnet or reducing the axial air gap. This also improves the axial stiffness of the bearing and reduces the manufacturing cost of the magnetic levitation bearing. Attached Figure Description

[0041] Figure 1 This refers to the magnetic levitation structure in existing technology;

[0042] Figure 2 A schematic diagram (axial section) illustrating the working principle of a permanent magnet biased radial bearing in the prior art;

[0043] Figure 3 for Figure 2 A schematic diagram of the working principle of a permanent magnet biased radial bearing (radial plane);

[0044] Figure 4 This is a schematic diagram illustrating the working principle of an axial magnetic levitation bearing in the prior art.

[0045] Figure 5 This is a schematic diagram (partial cross-section) of the internal structure of the hybrid magnetic levitation bearing in an embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the disassembly structure of the hybrid magnetic levitation bearing in an embodiment of the present invention;

[0047] Figure 7 This is a schematic diagram of the direction of each magnetic field in the hybrid magnetic levitation bearing in the embodiment of the present invention (the shell and axial section are omitted).

[0048] Figure 8 This is a schematic diagram showing the direction of each magnetic field in the hybrid magnetic levitation bearing in an embodiment of the present invention (the shell and radial plane are omitted).

[0049] The reference numerals in the attached figures are as follows:

[0050] 1. Housing; 11. Front housing; 111. Front positioning flange; 12. Rear housing; 121. Rear positioning flange; 2. Axial magnetic bearing assembly; 21. Inner magnetic ring; 211. Third axial positioning flange; 22. Outer magnetic ring; 221. Second axial positioning flange; 23. Axial permanent magnet ring; 24. Axial control winding; 25. Ring groove; 3. Front radial magnetic bearing assembly; 31. Front radial stator core; 32. Front radial control winding; 4. Rear radial magnetic bearing assembly; 41. Rear radial stator core; 42. Rear radial control winding; 5. Shaft; 51. Thrust section; 6. Radial permanent magnet ring; 61. First axial positioning flange. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0052] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0053] See also Figure 5 and Figure 8 As shown, according to an embodiment of the present invention, a hybrid magnetic levitation bearing is provided, comprising:

[0054] Housing 1, housing 1 forms a magnetic bearing accommodating space, and it is understood that housing 1 is a non-magnetic structure;

[0055] The axial magnetic bearing assembly 2 is connected within the magnetic bearing housing space and includes an inner magnetic ring 21, an outer magnetic ring 22, an axial permanent magnet ring 23, and an axial control winding 24. The outer magnetic ring 22, the axial permanent magnet ring 23, and the inner magnetic ring 21 are sequentially fitted from the outside to the inside along the radial direction of the inner magnetic ring 21.

[0056] The front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4 are connected to the opposite ends of the axial magnetic bearing assembly 2;

[0057] The rotating shaft 5 is inserted into the central through hole of the inner magnetic ring 21 with a gap. The aforementioned gap insertion means that after the rotating shaft 5 is inserted into the central through hole of the inner magnetic ring 21, an annular gap is formed between the two. This gap is also the displacement adjustment space of the aforementioned front radial magnetic bearing assembly 3 and rear radial magnetic bearing assembly 4 for the rotating shaft 5.

[0058] The radial permanent magnet ring 6 can provide a permanent magnet biasing magnetic field for the axial magnetic bearing assembly 2, the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4.

[0059] In this technical solution, on the one hand, the axial magnetic bearing assembly 2 forms an integrated structure between the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4, making the structure of the hybrid magnetic levitation bearing simpler and more compact, and occupying a smaller axial length space. This allows for a smaller overall length of the shaft 5, which helps reduce rotor deflection, increases the rotor's limiting speed, and reduces its natural frequency. On the other hand, in this invention, while the radial permanent magnet ring 6 provides radial and axial permanent magnet bias magnetic fields, an axial permanent magnet ring 23 is added inside the axial magnetic bearing assembly 2. This increases the bias magnetic field at the axial air gap, thereby increasing the ultimate load output of the axial magnetic bearing assembly 2 without increasing the volume of the permanent magnet or reducing the axial space air gap. This also improves the axial stiffness of the bearing and reduces the manufacturing cost of the magnetic levitation bearing.

[0060] See details Figure 7 As shown in the figure, the radial permanent magnet ring 6 forms a front radial bias magnetic field via the front radial stator core 31, the rotating shaft 5, and the outer magnetic ring 22, and a rear radial bias magnetic field via the rear radial stator core 41, the rotating shaft 5, and the outer magnetic ring 22. It also has some magnetic lines of force that extend into the axial air gap. Based on this, due to the addition of the axial permanent magnet ring 23, it forms a front axial bias magnetic field via the front ends of the outer magnetic ring 22, the rotating shaft 5, and the inner magnetic ring 21, and a rear axial bias magnetic field via the rear ends of the outer magnetic ring 22, the rotating shaft 5, and the inner magnetic ring 21. This superimposes the aforementioned radial bias magnetic field with the magnetic lines of force in the axial air gap, thereby increasing the magnetic field density in the axial air gap. This makes the axial output force and axial stiffness of the magnetic levitation bearing in this invention higher.

[0061] See Figure 5 As shown, in some embodiments, the shaft 5 has two thrust portions 51, which are spaced apart along the axial direction of the shaft 5, and the axial magnetic bearing assembly 2 is at least partially located in the gap space between the two thrust portions 51.

[0062] In this technical solution, the rotating shaft 5 and the two thrust portions 51 form an H-shaped structure. The axial magnetic bearing assembly 2 is placed in the gap space between the two thrust portions 51. This not only achieves the purpose of axial thrust on the rotating shaft 5 through both sides, but also further simplifies the structure of the magnetic levitation bearing. In this technical solution, the thrust portions 51 are connected to both ends of the rotating shaft 5 by assembly, which makes the structure of the magnetic levitation bearing more compact. In a specific embodiment, the thrust portions 51 are specifically heat-fitted onto the rotating shaft 5 in the form of thrust plates, making the connection of the thrust portions 51 more reliable and stable.

[0063] See also Figure 5 As shown, in some embodiments, the inner magnetic ring 21 and the outer magnetic ring 22 protrude from the end faces of the two ends of the axial permanent magnet ring 23 and form two annular grooves 25 with openings facing one side of the corresponding thrust portion 51. The axial control winding 24 has two sets, and each set of axial control windings 24 is wound in each annular groove 25.

[0064] like Figure 5 As shown, the two ends of the inner magnetic ring 21 and the outer magnetic ring 22 are directly opposite the thrust portion 51. That is, the aforementioned axial air gap is formed between the end faces of the inner magnetic ring 21 and the outer magnetic ring 22 and the thrust portion 51. The thickness of the axial air gap can be adjusted within a relatively reasonable range by adjusting the protrusion height of the end faces. The aforementioned annular groove 25 forms the assembly space for the axial control winding 24. The structure is simple, and the assembly of the axial control winding 24 is more stable and reliable.

[0065] In one specific embodiment, the axial control winding 24 is potted and assembled within the annular groove 25; and / or, the axial control winding 24 is bolted to the annular groove 25. In a more preferred embodiment, the aforementioned axial control winding 24 is fixed by a dual method of potting and bolting (e.g., screws). This allows the potting to form an insulating skeleton and improves the positional reliability and stability of the axial control winding 24.

[0066] See Figure 5 As shown, in one embodiment, the radial permanent magnet ring 6 is fitted between the outer magnetic ring 22 and the housing 1, and is clamped between the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4.

[0067] In this technical solution, the radial permanent magnet ring 6 is located between two radial magnetic bearing assemblies, which enables the hybrid magnetic levitation bearing to share a set of the aforementioned radial permanent magnet ring 6. This further simplifies the structure of the magnetic levitation bearing and further reduces the bearing manufacturing cost.

[0068] In one specific embodiment, the front radial magnetic bearing assembly 3 includes a front radial stator core 31 and a front radial control winding 32 wound on each magnetic pole tooth of the front radial stator core 31, and the rear radial magnetic bearing assembly 4 includes a rear radial stator core 41 and a rear radial control winding 42 wound on each magnetic pole tooth of the rear radial stator core 41. A front radial air gap is formed between each magnetic pole tooth of the front radial stator core 31 and a thrust portion 51, and a rear radial air gap is formed between each magnetic pole tooth of the rear radial stator core 41 and another thrust portion 51. The radial permanent magnet ring 6 is clamped between the front radial stator core 31 and the rear radial stator core 41.

[0069] In this technical solution, the front radial stator core 31 and the rear radial stator core 41 each correspond to the thrust portion 51 at one end, thereby allowing precise adjustment of the levitation radial position of the rotating shaft 5 by adjusting the front radial control winding 32 and the rear radial control winding 42. In some applications, because the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4 of the magnetic levitation bearing in this application are spaced apart axially on the rotating shaft 5, the rotating shaft 5 achieves dual-point support. Therefore, when applied to a motor, the motor can meet the levitation bearing requirements using only one set of hybrid magnetic levitation bearings of this invention.

[0070] The aforementioned front radial stator core 31 and rear radial stator core 41 are thermally fitted to the front housing 11 or rear housing 12, and can also be connected by screws. The aforementioned front radial control winding 32 and rear radial control winding 42 are fixedly connected to the corresponding magnetic pole teeth by winding and impregnation, respectively.

[0071] See Figure 6 As shown, in some embodiments, the housing 1 is formed by assembling a front housing 11 and a rear housing 12. The inner wall of the front housing 11 has a front positioning flange 111, and the inner wall of the rear housing 12 has a rear positioning flange 121. The radial permanent magnet ring 6 is clamped between the front positioning flange 111 and the rear positioning flange 121. It is understood that the protrusion height of the aforementioned front positioning flange 111 and rear positioning flange 121 should not create undue obstacles to the assembly of the corresponding front radial stator core 31 and rear radial stator core 41 with the front housing 11 and the rear housing 12, respectively. That is, their respective protrusion heights should not be too high. Specifically, when the aforementioned protrusion heights are thermally fitted between the front radial stator core 31 and the rear radial stator core 41 and the front housing 11 or the rear housing 12, the inner diameter of the flange is greater than the outer diameter of the radial stator core. The aforementioned front positioning flange 111 and rear positioning flange 121 can be rings, which can be integrally formed on the inner wall of the housing 1 by machining.

[0072] In this technical solution, the radial permanent magnet ring 6 is positioned axially by the front positioning flange 111 and the rear positioning flange 121, effectively preventing the radial permanent magnet ring 6 from moving axially. The radial permanent magnet ring 6 is thermally fitted with the front shell 11 and the rear shell 12.

[0073] See also Figure 6 As shown, one end of the inner ring wall of the radial permanent magnet ring 6 has a first axial positioning protrusion 61; and / or, one end of the inner ring wall of the outer magnetic ring 22 has a second axial positioning protrusion 221.

[0074] In this technical solution, the first axial positioning protrusion 61 can reliably position the axial position of the outer magnetic ring 22, and the second axial positioning protrusion 221 can reliably position the axial position of the axial permanent magnet ring 23, thereby facilitating the assembly of the axial magnetic bearing assembly 2. In another preferred embodiment, the outer ring wall of the inner magnetic ring 21 has a third axial positioning protrusion 211, which, along with the second axial positioning protrusion 221, is located at both ends of the axial permanent magnet ring 23, thereby enabling completely reliable axial positioning of both ends of the axial permanent magnet ring 23.

[0075] In some embodiments, the outer magnetic ring 22, the axial permanent magnet ring 23, and the inner magnetic ring 21 are thermally fitted together, which simplifies the assembly of the axial magnetic bearing assembly 2 and ensures reliable connection.

[0076] According to embodiments of the present invention, the present invention also provides an assembly method for the hybrid magnetic levitation bearing as described above, comprising the following steps:

[0077] The outer magnetic ring 22, the axial permanent magnet ring 23 and the inner magnetic ring 21 are sequentially assembled from the outside to the inside along the radial direction of the inner magnetic ring 21 to form the axial magnetic bearing assembly 2, and the radial permanent magnet ring 6 is assembled on the outside of the axial magnetic bearing assembly 2.

[0078] The front radial magnetic bearing assembly 3 is assembled inside the front housing 11, and the rear radial magnetic bearing assembly 4 is assembled inside the rear housing 12.

[0079] The front housing 11, which is assembled with the front radial magnetic bearing assembly 3, and the rear housing 12, which is assembled with the rear radial magnetic bearing assembly 4, are respectively assembled close to each other from both ends of the axial magnetic bearing assembly 2, and the radial permanent magnet ring 6 is placed in the magnetic bearing accommodating space of the housing 1.

[0080] Insert the rotating shaft 5 into the central through hole of the inner magnetic ring 21. It is understandable that the relevant components can also be fixed by bolts and stop.

[0081] In this technical solution, the hybrid magnetic levitation bearing formed by the aforementioned assembly method of the present invention has the following advantages: First, the axial magnetic bearing assembly 2 is located between the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4, making the structure of the hybrid magnetic levitation bearing simpler and more compact, and occupying less shaft length space. This allows for a smaller overall length of the shaft 5, which helps to reduce rotor deflection and increase the rotor's limiting speed. Second, in this invention, while the radial permanent magnet ring 6 provides radial and axial permanent magnet bias magnetic fields, an axial permanent magnet ring 23 is added inside the axial magnetic bearing assembly 2. This increases the bias magnetic field at the axial air gap, thereby increasing the ultimate load output of the axial magnetic bearing assembly 2 without increasing the volume of the permanent magnet or reducing the axial space air gap. This also improves the axial stiffness of the bearing and reduces the manufacturing cost of the magnetic levitation bearing.

[0082] In some embodiments, the rotating shaft 5 has two thrust portions 51, each thrust portion 51 being fitted onto both ends of the rotating shaft 5 and positioned corresponding to the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4, respectively. In this technical solution, the aforementioned thrust portions 51 are detachably connected to the rotating shaft 5, which facilitates the insertion of the rotating shaft 5 and makes the overall structure of the hybrid magnetic levitation bearing more compact.

[0083] According to an embodiment of the present invention, the present invention also provides an electric motor including the aforementioned hybrid magnetic levitation bearing. In this technical solution, by employing the aforementioned hybrid magnetic levitation bearing of the present invention, on the one hand, the axial magnetic bearing assembly 2 is located between the front radial magnetic bearing assembly 3 and the rear radial magnetic bearing assembly 4, making the structure of the hybrid magnetic levitation bearing simpler and more compact, and occupying less shaft length space. This allows for a smaller overall length of the shaft 5, which is beneficial for reducing rotor deflection and increasing the rotor's limiting speed. On the other hand, in the present invention, while the radial permanent magnet ring 6 provides radial and axial permanent magnet bias magnetic fields, an axial permanent magnet ring 23 is added inside the axial magnetic bearing assembly 2. This increases the bias magnetic field at the axial air gap, thereby increasing the ultimate load output of the axial magnetic bearing assembly 2 without increasing the volume of the permanent magnet or reducing the axial space air gap, improving the axial stiffness of the bearing, and reducing the manufacturing cost of the magnetic levitation bearing.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0085] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A hybrid magnetic bearing, characterized in that, include: The housing (1) has a magnetic bearing accommodating space. An axial magnetic bearing assembly (2) is connected within the magnetic bearing housing space and includes an inner magnetic ring (21), an outer magnetic ring (22), an axial permanent magnet ring (23), and an axial control winding (24). The outer magnetic ring (22), the axial permanent magnet ring (23), and the inner magnetic ring (21) are sequentially fitted from the outside to the inside along the radial direction of the inner magnetic ring (21). The front radial magnetic bearing assembly (3) and the rear radial magnetic bearing assembly (4) are connected to the opposite ends of the axial magnetic bearing assembly (2); The rotating shaft (5) is inserted into the central through hole of the inner magnetic ring (21) with a gap; The radial permanent magnet ring (6) can provide a permanent magnet bias magnetic field for the axial magnetic bearing assembly (2), the front radial magnetic bearing assembly (3) and the rear radial magnetic bearing assembly (4).

2. The hybrid magnetic levitation bearing according to claim 1, characterized in that, The rotating shaft (5) has two thrust portions (51) spaced apart along the axial direction of the rotating shaft (5), and the axial magnetic bearing assembly (2) is at least partially located in the gap space between the two thrust portions (51).

3. The hybrid magnetic levitation bearing according to claim 2, characterized in that, The inner magnetic ring (21) and the outer magnetic ring (22) protrude from the two end faces of the axial permanent magnet ring (23) and form two annular grooves (25) with openings facing one side of the corresponding thrust part (51). The axial control winding (24) has two sets, and each set of the axial control winding (24) is wound in the annular groove (25).

4. The hybrid magnetic levitation bearing according to claim 3, characterized in that, The axial control winding (24) is encapsulated and assembled within the annular groove (25); and / or, The axial control winding (24) is bolted to the annular groove (25).

5. The hybrid magnetic levitation bearing according to claim 2, characterized in that, The thrust portion (51) is heat-fitted onto the rotating shaft (5).

6. The hybrid magnetic levitation bearing according to claim 2, characterized in that, The radial permanent magnet ring (6) is fitted between the outer magnetic ring (22) and the housing (1), and is clamped between the front radial magnetic bearing assembly (3) and the rear radial magnetic bearing assembly (4).

7. The hybrid magnetic levitation bearing according to claim 6, characterized in that, The front radial magnetic bearing assembly (3) includes a front radial stator core (31) and a front radial control winding (32) wound on each magnetic pole tooth of the front radial stator core (31). The rear radial magnetic bearing assembly (4) includes a rear radial stator core (41) and a rear radial control winding (42) wound on each magnetic pole tooth of the rear radial stator core (41). A front radial air gap is formed between each magnetic pole tooth of the front radial stator core (31) and one of the thrust portions (51). A rear radial air gap is formed between each magnetic pole tooth of the rear radial stator core (41) and another thrust portion (51). The radial permanent magnet ring (6) is clamped between the front radial stator core (31) and the rear radial stator core (41).

8. The hybrid magnetic levitation bearing according to claim 1, characterized in that, The housing (1) is formed by assembling a front housing (11) and a rear housing (12). The inner wall of the front housing (11) has a front positioning flange (111), and the inner wall of the rear housing (12) has a rear positioning flange (121). The radial permanent magnet ring (6) is clamped between the front positioning flange (111) and the rear positioning flange (121).

9. The hybrid magnetic levitation bearing according to claim 1, characterized in that, One end of the inner ring wall of the radial permanent magnet ring (6) has a first axial positioning protrusion (61); and / or, One end of the inner ring wall of the outer magnetic ring (22) has a second axial positioning protrusion (221).

10. The hybrid magnetic levitation bearing according to claim 1, characterized in that, The outer magnetic ring (22), the axial permanent magnet ring (23), and the inner magnetic ring (21) are thermally assembled into one unit.

11. A method of assembling a hybrid magnetic bearing as claimed in claim 8, characterized in that, Includes the following steps: The outer magnetic ring (22), the axial permanent magnet ring (23) and the inner magnetic ring (21) are sequentially assembled from the outside to the inside along the radial direction of the inner magnetic ring (21) to form the axial magnetic bearing assembly (2), and the radial permanent magnet ring (6) is fitted on the outside of the axial magnetic bearing assembly (2); The front radial magnetic bearing assembly (3) is assembled inside the front housing (11), and the rear radial magnetic bearing assembly (4) is assembled inside the rear housing (12); The front shell (11) with the front radial magnetic bearing assembly (3) assembled and the rear shell (12) with the rear radial magnetic bearing assembly (4) assembled are respectively assembled close to each other from both ends of the axial magnetic bearing assembly (2), and the radial permanent magnet ring (6) is placed in the magnetic bearing accommodating space of the housing (1). The rotating shaft (5) is inserted into the central through hole of the inner magnetic ring (21).

12. The assembly method of the hybrid magnetic levitation bearing according to claim 11, characterized in that, The rotating shaft (5) has two thrust portions (51), and each thrust portion (51) is fitted onto both ends of the rotating shaft (5) and the positions correspond to the front radial magnetic bearing assembly (3) and the rear radial magnetic bearing assembly (4), respectively.

13. An electric machine characterized by Includes the hybrid magnetic levitation bearing according to any one of claims 1 to 10.

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