A magnetic levitation bearing based on unilateral permanent magnet bias

Abstract

This invention discloses a magnetic levitation bearing based on single-sided permanent magnet bias, aiming to solve the problems of traditional permanent magnet bias magnetic levitation bearings, such as complex structure, numerous components, high cost, large space occupation, and difficulty in adapting to space-constrained scenarios. The bearing includes a stator and a rotor. The stator has equidistantly distributed circumferential magnetic pole groups, with a first magnetic isolation gap between adjacent pole groups. Each pole group contains two magnetic pole teeth with control coils. A permanent magnet is located above the rotor within a second magnetic isolation gap between the teeth, providing the rotor with a levitation force against gravity. The permanent magnet is located in the bias magnetic field region of the stator opposite to the direction of gravity, with its two poles corresponding to the two magnetic pole teeth on either side. The magnetic pole teeth are engaged and fixed with the stator limiting rod through limiting grooves. This structure simplifies the layout, reduces components and space occupation, optimizes the magnetic field distribution, improves control accuracy and stability, and is suitable for space-constrained scenarios.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and in particular to a magnetic levitation bearing based on unilateral permanent magnet bias. Background Technology

[0002] Magnetic levitation bearings achieve shaft levitation through magnetic force, offering advantages such as no mechanical contact, low friction, and high precision, and have broad application prospects. Permanent magnet biased magnetic levitation bearings, as one type, rely on the synergistic effect of the bias magnetic field of a permanent magnet and the control magnetic field of an electromagnetic coil to ensure stable rotor levitation operation.

[0003] However, traditional permanent magnet bias levitation bearings have a complex structure, with the stator completely surrounding the rotor, containing a magnetic core, regularly distributed permanent magnets, and surrounding control windings. During operation, the permanent magnets provide a bias magnetic field, and the control windings adjust the magnetic field based on the rotor's position. This structure has many components, resulting in high manufacturing costs. In space-constrained applications such as micro-aircraft engines and small high-speed motors, it occupies a large space and cannot meet the requirements of compact designs. Summary of the Invention

[0004] The main objective of this invention is to provide a magnetic levitation bearing based on unilateral permanent magnet bias, which aims to solve the problems of traditional permanent magnet bias magnetic levitation bearings having complex structures, many parts, high costs, large space occupation, and difficulty in adapting to space-constrained scenarios.

[0005] To achieve the above objectives, this invention proposes a magnetic levitation bearing based on unilateral permanent magnet bias, comprising a stator and a rotor. A plurality of magnetic pole groups are disposed on the stator between the stator and the rotor, the magnetic pole groups being equidistantly distributed circumferentially on the stator, and a first magnetic isolation gap being provided between adjacent magnetic pole groups. Each magnetic pole group includes two magnetic pole teeth wound with control coils, and a second magnetic isolation gap is provided between two adjacent magnetic pole teeth. The invention also includes a permanent magnet disposed within the second magnetic isolation gap, the permanent magnet being located above the rotor to provide the rotor with a levitation force against gravity.

[0006] In one possible implementation, with the direction of gravity as a reference, the half of the stator that is away from the direction of gravity is a bias magnetic field region, and the permanent magnet is disposed in a second magnetic isolation gap within the bias magnetic field region.

[0007] In one possible implementation, the permanent magnet includes an N pole and an S pole, the N pole and the S pole of the permanent magnet corresponding to the magnetic pole teeth on both sides, respectively.

[0008] In one possible implementation, the magnetic pole teeth are provided with a first limiting groove and a second limiting groove extending along the stator axial direction, and the stator is provided with a limiting rod that engages with the first limiting groove and the second limiting groove.

[0009] In one possible implementation, the first limiting groove is located on the outer side of the magnetic pole tooth along the stator radial direction, and is used to limit the radial position of the magnetic pole tooth; the second limiting groove is located at one end of the magnetic pole tooth along the stator circumferential direction, and is used to limit the circumferential position of the magnetic pole tooth.

[0010] In one possible implementation, the permanent magnet is composed of several permanent magnet units that are magnetically attracted and fixed to each other. The several permanent magnet units are distributed in the second magnetic isolation gap along the circumference of the stator, and the magnetization direction of adjacent permanent magnet units is deflected by 90° in sequence along the circumference to form a Halbach array structure.

[0011] In one possible implementation, the permanent magnet unit has at least three segments, including a first unit, a second unit, and a third unit arranged in sequence. The magnetization direction of the first unit is radially outward along the stator, the magnetization direction of the second unit is tangential to the stator, and the magnetization direction of the third unit is radially inward along the stator.

[0012] In one possible implementation, the three permanent magnet units are all of equal size and length, and the magnetic poles of adjacent permanent magnet units are opposite, and they are bonded and fixed together by a non-magnetic adhesive layer.

[0013] In one possible implementation, a soft magnetic sheet is disposed between the mating surfaces of adjacent permanent magnet units, the soft magnetic sheet being made of silicon steel.

[0014] In one possible implementation, the remanence density of the second monomer is greater than that of the first and third monomers.

[0015] In summary, the beneficial effects of this application are as follows:

[0016] Compared with the prior art, the stator of the present invention is provided with magnetic pole groups that are equidistantly distributed in a circular pattern and have a first magnetic isolation gap in the middle. The magnetic field interference between adjacent magnetic pole groups is reduced, making the magnetic field control more precise and effective and optimizing the overall magnetic field distribution. Each magnetic pole group consists of magnetic pole teeth wound with control coils and a second magnetic isolation gap in the middle, which further optimizes the magnetic field distribution and avoids mutual influence between magnetic fields between magnetic pole teeth.

[0017] The permanent magnet is set in the second magnetic isolation gap and located above the rotor, providing the rotor with a levitation force to counteract gravity. This single-sided permanent magnet layout breaks away from the traditional ring structure, simplifies the structure, reduces the number of parts, and lowers manufacturing costs. With the direction of gravity as a reference, the permanent magnet is set in the bias magnetic field region of the stator, which is half away from the direction of gravity. This effectively utilizes the direction of gravity, improves levitation efficiency, and further simplifies the structure, reduces space occupation, and meets the compact design requirements of space-constrained scenarios such as micro aircraft engines and small high-speed motors.

[0018] The N and S poles of the permanent magnet correspond to the magnetic pole teeth on both sides, enhancing the magnetic field coupling between the permanent magnet and the magnetic pole teeth. This allows for better coordination between the bias magnetic field of the permanent magnet and the magnetic field of the control coil, improving the control accuracy of the rotor's levitation state. First and second limiting grooves on the magnetic pole teeth engage with the upper limit rod of the stator, respectively limiting the radial and circumferential positions of the magnetic pole teeth. This ensures the relative position accuracy of the magnetic pole group, improves structural stability and reliability, and ensures that all components maintain the correct position and good levitation performance during long-term operation. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a three-dimensional structural diagram of Embodiment 1 of the present invention;

[0021] Figure 2 This is an exploded structural diagram of Embodiment 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of the limiting rod of the present invention;

[0023] Figure 4 This is a magnetic flux density distribution diagram of Embodiment 1 of the present invention;

[0024] Figure 5 This is a three-dimensional structural diagram of Embodiment 3 of the present invention;

[0025] Figure 6 This is a schematic diagram of the bias magnetic circuit in Embodiment 3 of the present invention;

[0026] Figure 7 This is a schematic diagram of the magnetization direction of the permanent magnet unit in Embodiment 3 of the present invention.

[0027] Explanation of icon numbers:

[0028] 1. Stator; 2. Rotor; 3. Magnetic pole group; 30. First magnetic isolation gap; 31. Magnetic pole tooth; 32. Second magnetic isolation gap; 33. Permanent magnet; 330. First single unit; 331. Second single unit; 332. Third single unit; 4. Control coil; 5. First limiting groove; 6. Second limiting groove; 7. Limiting rod; 8. Soft magnetic sheet; 9. Position sensor.

[0029] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0031] Example 1

[0032] like Figure 1-4 As shown, this invention proposes a magnetic levitation bearing based on unilateral permanent magnet bias, including a stator 1 and a rotor 2. The rotor 2 is made of a magnetically conductive material, such as... Figure 1 As shown, a circumferentially distributed position sensor 9 is provided on the stator 1. The position sensor 9 can be used to detect the position of the rotor 2 in the bearing and send the data to an externally connected controller. The controller is connected to the bearing and the control coil 4 through a circuit.

[0033] When rotor 2 is running, the position sensors 9 distributed circumferentially on stator 1 monitor the position changes of rotor 2 in all radial directions in real time and continuously transmit the detected displacement signals to the externally connected controller. When rotor 2 experiences radial displacement due to external disturbances or load changes, the controller quickly analyzes the direction and amount of displacement based on the signals from position sensors 9 and calculates the control coil 4 that needs adjustment and the corresponding current change. At this time, the controller outputs the adjusted current to the target control coil 4 through the circuit, causing the control coil 4 to generate dynamic magnetic flux. This dynamic magnetic flux and the bias magnetic flux of permanent magnet 33 are superimposed or canceled at the air gap between the magnetic pole teeth 31 and rotor 2. If rotor 2 shifts to one side, the controller increases the current of the control coil 4 in the opposing magnetic pole group 3 on that side, causing the dynamic magnetic flux to superimpose with the bias magnetic flux, enhancing the attraction to rotor 2. At the same time, it decreases the current of the control coil 4 on the offset side, causing the dynamic magnetic flux to cancel the bias magnetic flux, weakening the attraction to rotor 2. Through this differential force adjustment, rotor 2 is pulled back to the center position, ensuring stability during operation.

[0034] Specifically, such as Figure 2As shown, several magnetic pole groups 3 are arranged on the stator 1 between the stator 1 and the rotor 2. The magnetic pole groups 3 are equidistantly distributed circumferentially on the stator 1, and a first magnetic isolation gap 30 is provided between adjacent magnetic pole groups 3. Each magnetic pole group 3 includes two opposing magnetic pole teeth 31, and a control coil 4 is wound on the magnetic pole teeth 31. A second magnetic isolation gap 32 is formed between two adjacent magnetic pole teeth 31. A permanent magnet 33 is provided in the second magnetic isolation gap 32. The permanent magnet 33 is located above the rotor 2 and is used to provide the rotor 2 with a levitation force to counteract gravity. In order to better enable the permanent magnet 33 to counteract the gravity of the rotor 2, the half of the stator 1 opposite to the direction of gravity is designated as the bias magnetic field region, and the permanent magnet 33 is placed in the second magnetic isolation gap 32 within the bias magnetic field region. The permanent magnet 33 includes an N pole and a S pole, and the N pole and S pole of the permanent magnet 33 correspond to the magnetic pole teeth 31 on both sides, respectively.

[0035] In the static state, the permanent magnet 33 located in the bias magnetic field region, that is, the half of the stator 1 away from the direction of gravity, in the second magnetic isolation gap 32, has its N pole and S pole corresponding to the magnetic pole teeth 31 on both sides, thus forming a stable bias magnetic flux loop: the magnetic flux of the permanent magnet 33 starts from the N pole, is conducted to the rotor 2 through the magnetic pole teeth 31 on one side, and then flows back to the S pole of the permanent magnet 33 through the magnetic pole teeth 31 on the other side of the rotor 2. This closed loop provides the rotor 2 with a continuous upward levitation force, which just counteracts the gravity of the rotor 2 itself, so that the rotor 2 can maintain a basic levitation state when there is no current input from the control coil 4, without the need for additional energy to maintain static balance, thereby significantly reducing the standby power consumption of the system.

[0036] When the rotor 2 experiences radial displacement due to external disturbances or load changes during rotation, the control coils 4 distributed on each magnetic pole group 3 dynamically adjust according to the displacement signal. Specifically, if the rotor 2 shifts in a certain direction, the control coil 4 on the corresponding magnetic pole tooth 31 generates additional magnetic flux through current changes. This additional magnetic flux is superimposed on the bias magnetic flux of the permanent magnet 33, enhancing the attraction to the rotor 2. Conversely, the control coil 4 in the opposite direction weakens the magnetic flux by reducing the current, creating a reverse force difference that pushes the rotor 2 back to the center position. In this adjustment mechanism, the first magnetic isolation gap 30 and the second magnetic isolation gap 32 play a crucial role: the first magnetic isolation gap 30 isolates the magnetic flux of adjacent magnetic pole groups 3 from each other, avoiding magnetic flux interference between different magnetic pole groups 3 and ensuring that the adjustment force in each direction is independently controllable; the second magnetic isolation gap 32 limits magnetic flux crosstalk between two magnetic pole teeth 31 within the same group, allowing the bias magnetic flux of the permanent magnet 33 and the adjustment magnetic flux of the coil to be concentrated on the rotor 2, reducing ineffective magnetic flux leakage and improving the utilization efficiency of the magnetic field.

[0037] In addition, according to the appendix Figure 4As shown in the figure, the compatibility between the magnetic flux distribution and the structural design of this magnetic levitation bearing scheme can be clearly observed, from which the following conclusions can be drawn:

[0038] The permanent magnet 33 forms a stable closed magnetic flux loop within the second magnetic isolation gap 32 in the bias magnetic field region. Its magnetic flux starts from the N pole of the permanent magnet 33, extends towards the rotor 2 through the magnetic pole teeth 31 on one side, passes through the rotor 2, and flows back to the S pole of the permanent magnet 33 through the magnetic pole teeth 31 on the other side. This path is completely consistent with the design expectation, indicating that the correspondence between the N pole and S pole of the permanent magnet 33 and the magnetic pole teeth 31 on both sides is accurate. It can effectively provide the rotor 2 with a bias levitation force to counteract gravity, so that the rotor 2 can maintain a basic levitation state when there is no current in the control coil 4, which confirms the rationality of the single-sided permanent magnet bias design.

[0039] Meanwhile, the figure shows that the magnetic flux density at the first magnetic isolation gap 30 and the second magnetic isolation gap 32 is significantly lower than that in the magnetic pole teeth 31 and the rotor 2 region, presenting a clear low magnetic flux region. This indicates that the magnetic isolation gap successfully blocked the diffusion of magnetic flux to the adjacent magnetic pole group 3 or non-target region, avoiding energy waste caused by magnetic flux leakage, and making the magnetic flux concentrated on the effective path of "permanent magnet 33 - magnetic pole teeth 31 - rotor 2", thus improving the efficiency of magnetic energy utilization.

[0040] Furthermore, there is an adjustable magnetic flux gradient around the area of ​​the magnetic pole teeth 31 around which the control coil 4 is wound. When current is applied to the coil, the dynamic magnetic flux it generates can be smoothly superimposed or canceled by the bias magnetic flux of the permanent magnet 33. In the figure, this is shown as the magnetic flux density in the corresponding area increasing or decreasing regularly with the change of current. This indicates that the control coil 4 can achieve precise correction of the radial displacement of the rotor 2 through current adjustment. In particular, when the rotor 2 is offset due to disturbance, the coil in the corresponding direction can quickly generate directional force through magnetic flux change, pushing the rotor 2 back to the center position.

[0041] The magnetic flux distribution around rotor 2 exhibits a symmetrical and smooth characteristic, without local magnetic flux concentration or disorder. This is due to the stability of the bias magnetic flux of permanent magnet 33 and the constraint effect of the magnetic isolation gap, which ensures that the radial force on rotor 2 is balanced, providing a basis for stable levitation. The difference in magnetic flux between the bias magnetic field area and other areas further verifies that the design of setting permanent magnet 33 only above rotor 2 can specifically strengthen the force against the direction of gravity, reducing the extra burden on control coil 4, and explaining the reason for the reduction in system power consumption from the perspective of magnetic flux.

[0042] Compared to existing technologies, this solution solves several key problems and achieves significant technical effects. Traditional pure active magnetic levitation bearings require a continuous input of large initial and bias currents to the control coil 4 to counteract the gravity of the rotor 2 and maintain levitation, resulting in high power consumption. In contrast, this solution directly counteracts the gravity of the rotor 2 through the bias flux provided by the single-sided permanent magnet 33. When statically levitating, there is almost no need for the control coil 4 to output current, which greatly reduces the system power consumption, especially in low-speed or static operation scenarios.

[0043] Existing hybrid magnetic levitation bearings mostly employ a symmetrically distributed permanent magnet 33 structure. While this can balance radial forces, it still requires the coil 4 to continuously output additional current in the vertical direction against gravity. Furthermore, the symmetrically distributed permanent magnet 33 easily leads to magnetic flux leakage in non-target areas, reducing magnetic energy utilization. This solution places the permanent magnet 33 only in the bias magnetic field region of the stator 1 away from the direction of gravity, specifically strengthening the levitation force against gravity. Simultaneously, in conjunction with the first and second magnetic isolation gaps 32, it effectively reduces magnetic flux leakage, increasing the effective levitation force with the same amount of permanent magnet 33 and significantly improving magnetic energy utilization.

[0044] Example 2

[0045] Based on Example 1, such as Figure 2-3 As shown, the magnetic pole tooth 31 is provided with a first limiting groove 5 and a second limiting groove 6 extending along the axial direction of the stator 1, and the stator 1 is provided with a limiting rod 7 that engages with the first limiting groove 5 and the second limiting groove 6. The first limiting groove 5 is located on the outer side of the magnetic pole tooth 31 along the radial direction of the stator 1, and is used to limit the radial position of the magnetic pole tooth 31; the second limiting groove 6 is located at one end of the magnetic pole tooth 31 along the circumferential direction of the stator 1, and is used to limit the circumferential position of the magnetic pole tooth 31.

[0046] The mechanical constraint structure formed by the first limiting groove 5 and the second limiting groove 6 on the magnetic pole tooth 31 and the limiting rod 7 on the stator 1 through the interlocking can ensure the long-term stability of the relative position between the magnetic pole tooth 31 and the stator 1 and the rotor 2, thereby providing a structural basis for the reliable operation of the magnetic levitation bearing.

[0047] Specifically, the first limiting groove 5 is located radially outside the magnetic pole tooth 31. After engaging with the limiting rod 7 on the stator 1, it can directly block the movement of the magnetic pole tooth 31 along the radial direction of the stator 1. This constraint can prevent the radial displacement of the magnetic pole tooth 31 caused by magnetic pull, vibration, or thermal expansion and contraction, thereby ensuring that the air gap between the magnetic pole tooth 31 and the rotor 2 remains uniform. The second limiting groove 6 is located at one circumferential end of the magnetic pole tooth 31. After engaging with the corresponding limiting rod 7, it can restrict the rotation or displacement of the magnetic pole tooth 31 along the circumferential direction of the stator 1, ensuring that the interval between adjacent magnetic pole groups 3 and the relative position of two magnetic pole teeth 31 in the same group remain fixed, avoiding asymmetrical magnetic field distribution caused by circumferential displacement.

[0048] The direct effect of this dual-limiting structure is reflected in the stability of the magnetic circuit: the radial position of the magnetic pole teeth 31 is stable, which maintains the uniformity of the air gap. The uniformity of the air gap is a prerequisite for the stability of the magnetic flux density. The stable magnetic flux density means that the bias levitation force provided by the permanent magnet 33 and the adjustment force generated by the control coil 4 will not change abruptly due to air gap fluctuations. The radial force on the rotor 2 is more balanced, and the levitation stability is significantly improved. At the same time, the circumferential position of the magnetic pole teeth 31 is fixed, which ensures that the spacing of adjacent magnetic pole groups 3 is consistent. The first magnetic isolation gap 30 can continuously and effectively block magnetic flux interference between groups, avoid magnetic flux leakage or crosstalk caused by changes in spacing, and maintain the magnetic energy utilization efficiency. The relative position of the two magnetic pole teeth 31 in the same group is stable, which also ensures that the correspondence between the permanent magnet 33 in the second magnetic isolation gap 32 and the magnetic pole teeth 31 on both sides is always accurate, ensuring that the closed loop of the bias magnetic flux is smooth and further strengthening the levitation stability against gravity.

[0049] Example 3

[0050] Based on Example 1, the structure of the permanent magnet 33 was improved.

[0051] like Figure 5-7 As shown, in this embodiment, the permanent magnet 33 adopts a Halbach array structure with multiple individual units. Through the orderly arrangement and characteristic optimization of the permanent magnet units, a synergistic effect of magnetic field focusing and stable operation is achieved. Overall, the permanent magnet 33 is composed of several permanent magnet units distributed along the circumference of the stator 1 in the second magnetic isolation gap 32. Adjacent permanent magnet units are fixed by magnetic attraction, and their magnetization direction is deflected by 90° along the circumference in sequence, forming a typical Halbach array. The core advantage of this array structure is that by utilizing the superposition of the magnetic fields of adjacent units, the magnetic flux is spontaneously focused towards the inner side of the rotor 2, while weakening the magnetic flux away from the outer side of the rotor 2, thereby enhancing the magnetic flux density of the effective magnetic circuit and reducing useless leakage.

[0052] Specifically, the permanent magnet unit contains at least three segments, namely the first unit 330, the second unit 331, and the third unit 332, and the three segments are of the same size and length to ensure uniform circumferential distribution. Among them, the magnetization direction of the first unit 330 is radially outward along the stator 1, the magnetization direction of the second unit 331 is tangential to the stator 1, and the magnetization direction of the third unit 332 is radially inward along the stator 1. The magnetization directions of these three units are successively deflected by 90° along the circumference, which means that the end closer to the outside of the stator 1 is the N pole, the end closer to the rotor 2 is the S pole, and the side closer to the second unit 331 along the circumference has an S pole due to the closed magnetic field line characteristics. The magnetization direction of the second unit 331 is clockwise along the tangential to the stator 1. Its left side along the circumference is the N pole, and its right side is the S pole. This tangential magnetization allows it to naturally receive the magnetic field of the first unit 330 and guide its direction. The magnetization direction of the third unit 332 is radially inward along the stator 1. Its end closer to the rotor 2 is the N pole, the end closer to the outside is the S pole, and the side closer to the second unit 331 along the circumference has an N pole. It is this successive 90° deflection of the magnetization direction that makes the mating surfaces of adjacent units form a strict opposite pole correspondence: the S pole side of the first unit 330 is opposite to the N pole side of the second unit 331, and the S pole side of the second unit 331 is opposite to the N pole side of the third unit 332. According to the basic characteristic of magnets that "opposite poles attract each other", a continuous and stable magnetic attraction force will be generated between adjacent units. This force, combined with the physical bonding of the non-magnetic adhesive layer, can effectively prevent the units from loosening and shifting under the action of vibration or magnetic field force, and also avoid the magnetic flux shunting problem that may be caused by using magnetic materials for fixation, thus ensuring the integrity of the magnetic field path.

[0053] Meanwhile, the arrangement of the three units ensures the orthogonality of the array, and the combination of radial and tangential magnetization allows the magnetic flux to start from the first unit 330, be guided by the tangential direction of the second unit 331, and finally converge inward by the third unit 332, forming a reinforced magnetic flux path pointing towards the rotor 2.

[0054] Meanwhile, a soft magnetic sheet 8 made of silicon steel can be added between the bonding surfaces of adjacent units. The high permeability of the soft magnetic material reduces the magnetic resistance of the bonding surface, promotes the smooth transmission of the magnetic field between units, and further reduces magnetic flux loss.

[0055] Furthermore, the remanence density of the second unit 331 is designed to be greater than that of the first unit 330 and the third unit 332. This is because the second unit 331, as the core component magnetized along the tangential direction, plays a key role in guiding the radial magnetic flux direction and strengthening the magnetic flux superposition on both sides of the rotor. A higher remanence density can enhance the magnetic field strength in the tangential direction, forming a stronger synergy with the magnetic field of the radial unit, and further improving the effective magnetic flux density on both sides of the rotor.

[0056] Compared to Example 1, this example improves upon the original solution by using a multi-unit Halbach array structure permanent magnet 33, specifically addressing the core issues of low magnetic flux utilization efficiency, insufficient levitation stability, and limited control response sensitivity. This results in superior operational performance. The specific reasons and effects are as follows:

[0057] First, the problem of uneven magnetic flux distribution and severe leakage in the single permanent magnet 33 is solved, significantly improving the effective magnetic flux density on the rotor 2 side. Although the single permanent magnet 33 in Example 1 can provide bias magnetic flux, due to the single magnetization direction, the magnetic flux inevitably leaks to the outside of the stator 1 when it is transmitted to the rotor 2 side, resulting in a large amount of magnetic energy being wasted on ineffective paths, and the actual magnetic flux density obtained on the rotor 2 side is limited. In contrast, the Halbach array in this embodiment uses the principle of magnetic field superposition to make the magnetic flux spontaneously focus on the rotor 2 side by sequentially deflecting the magnetization direction of three individual units by 90°: the radial magnetic flux of the first unit 330 is guided by the circumferential magnetic field of the second unit 331 and superimposes with the radial inward magnetic flux of the third unit 332 on the rotor 2 side, while the magnetic flux on the outside of the stator 1 is greatly weakened due to directional cancellation. This focusing effect directly reduces magnetic flux leakage, significantly increasing the effective magnetic flux density on the rotor 2 side, which in turn enhances the bias levitation force provided by the permanent magnet 33. This is because the levitation force is proportional to the square of the magnetic flux density, and a higher effective magnetic flux density directly translates into a stronger ability to resist gravity, so that the rotor 2 can remain stably levitated even if the load fluctuates slightly.

[0058] Secondly, the problem of poor magnetic flux stability and susceptibility to mechanical vibration of the single permanent magnet 33 is solved, improving long-term operational reliability. In Example 1, the single permanent magnet 33 is only fixed to the second magnetic isolation gap 32 by a mechanical structure. During long-term operation, it is easily loosened by the vibration of the rotor 2 and the fluctuation of magnetic pull, resulting in the relative positional displacement of the permanent magnet 33 and the magnetic pole teeth 31, which in turn causes magnetic flux path distortion and levitation force fluctuation. In this example, adjacent permanent magnet units are double-fixed by opposite pole magnetic attraction and non-magnetic adhesive layer: the magnetic attraction force of the opposite pole bonding surface forms a continuous self-tightening force, which, combined with the physical bonding of the non-magnetic adhesive layer, keeps the relative positional accuracy of the permanent magnet 33 and the magnetic pole teeth 31 within a very small range, and is not easy to loosen even with long-term vibration. At the same time, the silicon steel soft magnetic sheet 8 added to the bonding surface reduces the magnetic resistance between units, avoids magnetic flux abrupt changes caused by small gaps, and further ensures magnetic flux stability. This structure significantly reduces the amplitude of levitation force fluctuations compared to Example 1, thereby reducing the micro-vibration phenomenon of rotor 2 caused by magnetic flux instability at its source.

[0059] Furthermore, the problem of insufficient dynamic adjustment sensitivity of control coil 4 is solved, achieving more precise displacement correction. In Example 1, the magnetic flux distribution of the single permanent magnet 33 exhibits a certain degree of nonlinearity, with a faster decrease in magnetic flux density near the edge. This leads to unstable magnetic flux superposition when current is applied to control coil 4, resulting in a nonlinear relationship between current and levitation force, which easily causes overshoot or lag when adjusting the displacement of rotor 2. In this example, the Halbach array makes the magnetic flux distribution on the rotor 2 side more uniform, reducing the difference in magnetic flux density at radial points. Moreover, because the magnetic flux is focused towards the rotor 2 side, the dynamic magnetic flux generated by control coil 4 can more efficiently superimpose or cancel the bias magnetic flux, significantly improving control accuracy. For example, when rotor 2 shifts in a certain direction, only a small current needs to be applied to the corresponding coil to generate sufficient correction force through magnetic flux superposition. The response speed is significantly faster than in Example 1, effectively avoiding the decrease in rotor 2 stability caused by adjustment lag.

[0060] Finally, further optimization was achieved in energy consumption control. In Example 1, due to excessive magnetic flux leakage in the single permanent magnet 33, the control coil 4 needed to supply additional current to compensate for the insufficient magnetic flux in order to maintain sufficient levitation force, indirectly increasing power consumption. However, in this example, the permanent magnet 33 achieves significant reduction in compensation current of the control coil 4 under the same levitation force requirement by focusing magnetic flux and reducing magnetic reluctance. At the same time, the more stable magnetic flux eliminates the need for frequent current adjustments in the coil, further reducing dynamic power consumption. This approach of replacing current compensation with magnetic circuit optimization reduces the overall system energy consumption compared to Example 1, making it particularly suitable for high-speed rotation scenarios with stringent low power consumption requirements.

[0061] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0062] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A magnetic bearing based on single-sided permanent magnetic biasing, comprising a stator (1) and a rotor (2), characterized in that, A plurality of magnetic pole groups (3) are provided on the stator (1) between the stator (1) and the rotor (2). The plurality of magnetic pole groups (3) are circumferentially distributed at equal intervals on the stator (1), and a first magnetic isolation gap (30) is provided between adjacent magnetic pole groups (3). Each magnetic pole group (3) includes two magnetic pole teeth (31) wound with control coils (4), and a second magnetic isolation gap (32) is provided between two adjacent magnetic pole teeth (31). It also includes a permanent magnet (33) disposed in the second magnetic isolation gap (32). The permanent magnet (33) is located above the rotor (2) and is used to provide the rotor (2) with a levitation force against gravity.

2. A single-sided permanent magnet biased magnetic bearing according to claim 1, wherein, With the direction of gravity as a reference, the half of the stator (1) that is away from the direction of gravity is the bias magnetic field region, and the permanent magnet (33) is disposed in the second magnetic isolation gap (32) within the bias magnetic field region.

3. A single-sided permanent magnet biased magnetic bearing according to claim 2, wherein, The permanent magnet (33) includes an N pole and an S pole, and the N pole and S pole of the permanent magnet (33) correspond to the magnetic pole teeth (31) on both sides respectively.

4. A magnetic levitation bearing based on unilateral permanent magnet bias according to any one of claims 1-3, characterized in that, The magnetic pole teeth (31) are provided with a first limiting groove (5) and a second limiting groove (6) extending along the axial direction of the stator (1), and the stator (1) is provided with a limiting rod (7) that engages with the first limiting groove (5) and the second limiting groove (6).

5. A magnetic levitation bearing based on unilateral permanent magnet bias according to claim 4, characterized in that, The first limiting groove (5) is located on the outer side of the magnetic pole tooth (31) along the radial direction of the stator (1) and is used to limit the radial position of the magnetic pole tooth (31); the second limiting groove (6) is located at one end of the magnetic pole tooth (31) along the circumferential direction of the stator (1) and is used to limit the circumferential position of the magnetic pole tooth (31).

6. A magnetic levitation bearing based on unilateral permanent magnet bias according to claim 4, characterized in that, The permanent magnet (33) is composed of several permanent magnet units that are magnetically attracted and fixed to each other. The several permanent magnet units are distributed in the second magnetic isolation gap (32) along the circumference of the stator (1), and the magnetization direction of adjacent permanent magnet units is deflected by 90° along the circumference to form a Halbach array structure.

7. A magnetic levitation bearing based on unilateral permanent magnet bias according to claim 6, characterized in that, The permanent magnet unit has at least three segments, including a first unit (330), a second unit (331), and a third unit (332) arranged in sequence. The magnetization direction of the first unit (330) is radially outward along the stator (1), the magnetization direction of the second unit (331) is tangential to the circumference of the stator (1), and the magnetization direction of the third unit (332) is radially inward along the stator (1).

8. A magnetic levitation bearing based on unilateral permanent magnet bias according to claim 7, characterized in that, The three permanent magnet units are all the same size and length, and the magnetic poles of adjacent permanent magnet units are opposite, and they are bonded and fixed together by a non-magnetic adhesive layer.

9. A magnetic levitation bearing based on unilateral permanent magnet bias according to any one of claims 6-8, characterized in that, A soft magnetic sheet (8) is provided between the mating surfaces of adjacent permanent magnet units, and the soft magnetic sheet (8) is made of silicon steel.

10. A magnetic levitation bearing based on unilateral permanent magnet bias according to claim 8, characterized in that, The remanence density of the second monomer (331) is greater than that of the first monomer (330) and the third monomer (332).

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