Magnetic suspension bearing based on unilateral permanent magnet bias

Abstract

The invention discloses a magnetic suspension bearing based on unilateral permanent magnet bias, and aims at solving the problems that a traditional permanent magnet bias magnetic suspension bearing is complex in structure, large in number of parts, high in cost, large in occupied space and difficult to adapt to space-limited scenes. The bearing comprises a stator and a rotor, magnetic pole sets are circumferentially distributed on the stator at equal intervals, and a first magnetic isolation gap is formed between every two adjacent magnetic pole sets; each magnetic pole set comprises two magnetic pole teeth with control coils, and a permanent magnet located above the rotor is arranged in a second magnetic isolation gap between the teeth and provides suspension force resisting gravity for the rotor. The permanent magnet is arranged in a bias magnetic field area of the stator deviating from the gravity direction, and two poles of the permanent magnet correspond to two-side magnetic pole teeth; and the magnetic pole teeth are embedded and fixed with the stator limiting rods through the limiting grooves. The structure simplifies layout, reduces part and space occupation, optimizes magnetic field distribution, improves control precision and stability, and is suitable for space limited scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings, and in particular to a magnetic suspension bearing based on unilateral permanent magnet bias. Background Art

[0002] Magnetic bearings (MABs) utilize magnetic field forces to achieve shaft levitation. They offer advantages such as zero mechanical contact, low friction, and high precision, and have broad application prospects. Permanent magnet biased MABs, one such type, rely on the synergistic effect of a permanent magnet bias field and an electromagnetic coil control field to ensure stable rotor levitation.

[0003] However, conventional permanent magnet biased magnetic bearings (PMBs) have a complex structure. The stator completely surrounds the rotor and consists of a magnetic core, regularly spaced permanent magnets, and a surrounding control winding. During operation, the permanent magnets provide a bias magnetic field, while the control winding adjusts the magnetic field based on rotor position feedback. This structure has numerous components and 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 purpose of the present invention is to provide a magnetic levitation bearing based on unilateral permanent magnet bias, aiming to solve the problems of traditional permanent magnet bias magnetic levitation bearings with complex structure, many parts, high cost, large space occupation, and difficulty in adapting to space-constrained scenarios.

[0005] To achieve the above-mentioned objectives, the present invention proposes a magnetic levitation bearing based on unilateral permanent magnet bias, comprising a stator and a rotor, wherein a plurality of magnetic pole groups arranged on the stator are arranged between the stator and the rotor, and the plurality of magnetic pole groups are equidistantly distributed circumferentially on the stator, and a first magnetic isolation gap is arranged between adjacent magnetic pole groups; each group of the magnetic pole groups includes two magnetic pole teeth wound with a control coil, and a second magnetic isolation gap is arranged between two adjacent magnetic pole teeth; and further comprising a permanent magnet arranged in the second magnetic isolation gap, wherein the permanent magnet is located above the rotor and is used to provide the rotor with a suspension force to counteract gravity.

[0006] In a possible implementation, with the direction of gravity as a reference, the half region of the stator facing 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 a possible implementation, the permanent magnet includes an N pole and an S pole, and the N pole and the S pole of the permanent magnet correspond to the magnetic pole teeth on both sides respectively.

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

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

[0010] In a possible implementation, the permanent magnet is composed of a plurality of permanent magnet monomers that are fixed by magnetic attraction, and the plurality of permanent magnet monomers are distributed along the circumferential direction of the stator in the second magnetic gap, and the magnetization directions of adjacent permanent magnet monomers are sequentially deflected by 90 degrees along the circumferential direction to form a Halbach array structure.

[0011] In a possible implementation, the permanent magnet monomer has at least three sections, including a first monomer, a second monomer and a third monomer arranged in sequence, the magnetization direction of the first monomer is outward along the radial direction of the stator, the magnetization direction of the second monomer is along the tangent direction of the circumferential direction of the stator, and the magnetization direction of the third monomer is inward along the radial direction of the stator.

[0012] In a possible implementation, the sizes of the three sections of the permanent magnet monomer are equal, and the magnetic pole polarities of adjacent permanent magnet monomers are opposite and are fixed by a non-magnetic glue layer.

[0013] In a possible implementation, a soft magnetic sheet is arranged between the bonding surfaces of adjacent permanent magnet monomers, and the soft magnetic sheet is made of silicon steel.

[0014] In a possible implementation, the residual magnetism density of the second monomer is greater than that of the first monomer and the third monomer.

[0015] In summary, the application has the following advantages:

[0016] Compared with the prior art, the stator of the application is provided with magnetic pole groups that are distributed at equal distances along the circumferential direction and have first magnetic gaps in the middle, the magnetic field interference between adjacent magnetic pole groups is reduced, the magnetic field control is more accurate and effective, and the overall magnetic field distribution is optimized; each magnetic pole group is composed of a magnetic pole tooth wound with a control coil and a second magnetic gap in the middle, which further optimizes the magnetic field distribution and avoids the mutual influence of the magnetic fields between the magnetic pole teeth.

[0017] The permanent magnet is arranged in the second magnetic gap and above the rotor, and provides a suspension force against gravity for the rotor. This one-sided permanent magnet layout breaks the traditional ring structure, simplifies the structure, reduces the number of parts, and reduces the manufacturing cost. Taking the direction of gravity as a reference, the permanent magnet is arranged in the bias magnetic field area of the half area of the stator away from the direction of gravity, effectively utilizes the direction of gravity, improves the suspension efficiency, further simplifies the structure, reduces the space occupation, and meets the compact design requirements of space-limited scenes such as micro-aircraft engines and small high-speed motors.

[0018] The N-pole and S-pole of the permanent magnet correspond to the two side magnetic pole teeth respectively, the magnetic field coupling between the permanent magnet and the magnetic pole teeth is enhanced, the bias magnetic field of the permanent magnet and the magnetic field of the control coil are better coordinated, and the control precision of the rotor in the suspended state is improved. The first and second limiting grooves on the magnetic pole teeth are embedded with the limiting rods on the stator, the radial and circumferential positions of the magnetic pole teeth are limited respectively, the relative position accuracy of the magnetic pole groups is ensured, the structural stability and reliability are improved, the correct positions of the components are ensured in long-term operation, and the good suspension performance is maintained. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the drawings shown.

[0020] Figure 1 It is a perspective structural view of the embodiment 1 of the present application.

[0021] Figure 2 It is an explosion structural view of the embodiment 1 of the present application.

[0022] Figure 3 It is a structural schematic view of the limiting rod of the present application.

[0023] Figure 4 It is a magnetic flux density distribution view of the embodiment 1 of the present application.

[0024] Figure 5 It is a perspective structural view of the embodiment 3 of the present application.

[0025] Figure 6 It is a bias magnetic circuit schematic view of the embodiment 3 of the present application.

[0026] Figure 7 It is a magnetization direction schematic view of the permanent magnet monomer of the embodiment 3 of the present application.

[0027] Explanation of reference numerals:

[0028] 1, stator; 2, rotor; 3, magnetic pole group; 30, first magnetic gap; 31, magnetic pole tooth; 32, second magnetic gap; 33, permanent magnet; 330, first monomer; 331, second monomer; 332, third monomer; 4, control coil; 5, first limiting groove; 6, second limiting groove; 7, limiting rod; 8, soft magnetic sheet; 9, position sensor.

[0029] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0030] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0031] Embodiment 1

[0032] As shown in Figures 1-4 The present application proposes a single-sided permanent magnet biased magnetic bearing, which comprises a stator 1 and a rotor 2 made of magnetic conductive material, as shown in Figure 1 The stator 1 is provided with circumferentially distributed position sensors 9, which can be used to detect the position of the rotor 2 in the bearing and send data to the externally connected controller, and the controller is connected to the bearing and control coils 4 through a circuit.

[0033] When the rotor 2 is running, the circumferentially distributed position sensors 9 on the stator 1 will monitor the position changes of the rotor 2 in each direction in the radial direction in real time, and continuously transmit the detected displacement signals to the externally connected controller. When the rotor 2 appears radial deviation due to external disturbance or load change, the controller will quickly analyze the deviation direction and deviation amount according to the signal from the position sensor 9, and calculate the control coil 4 and the corresponding current change amount that needs to be adjusted. At this time, the controller outputs the adjusted current to the target control coil 4 through the circuit, so that the control coil 4 generates dynamic magnetic flux, which forms superposition or offset with the bias magnetic flux of the permanent magnet 33 at the air gap between the magnetic pole teeth 31 and the rotor 2: if the rotor 2 deviates to one side, the controller will increase the current of the control coil 4 in the opposite magnetic pole group 3 on that side, so that the dynamic magnetic flux and the bias magnetic flux are superimposed, and the attraction force to the rotor 2 is enhanced, while the current of the control coil 4 on the deviation side is reduced, so that the dynamic magnetic flux and the bias magnetic flux are offset, and the attraction force to the rotor 2 is weakened. Through the adjustment of such differential force, the rotor 2 is pulled back to the center position, ensuring stability during operation.

[0034] Specifically, as shown in Figure 2As shown, a plurality of magnetic pole groups 3 are arranged on the stator 1 between the stator 1 and the rotor 2, the plurality of magnetic pole groups 3 are equidistantly distributed on the stator 1, and a first magnetic gap 30 is arranged between adjacent magnetic pole groups 3; each magnetic pole group 3 comprises two oppositely arranged magnetic pole teeth 31, the magnetic pole teeth 31 are wound with control coils 4, a second magnetic gap 32 is formed between adjacent two magnetic pole teeth 31, a permanent magnet 33 is arranged in the second magnetic gap 32, the permanent magnet 33 is located above the rotor 2, and is used to provide a suspension force against gravity for the rotor 2; in order to better enable the permanent magnet 33 to counteract the gravity of the rotor 2, with the gravity direction as a reference, half of the region of the stator 1 away from the gravity direction is a bias magnetic field region, and the permanent magnet 33 is arranged in the second magnetic gap 32 in the bias magnetic field region. The permanent magnet 33 comprises an N-pole and an S-pole, and the N-pole and the S-pole of the permanent magnet 33 correspond to the two magnetic pole teeth 31 on the two sides, respectively.

[0035] In a static state, the permanent magnet 33 in the second magnetic gap 32 in the bias magnetic field region, i.e., half of the region of the stator 1 away from the gravity direction, has its N-pole and S-pole corresponding to the two magnetic pole teeth 31 on the two sides, respectively, thereby 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 one magnetic pole tooth 31, and then flows back to the S-pole of the permanent magnet 33 through the magnetic pole tooth 31 on the other side of the rotor 2, which forms a closed loop and provides a continuous upward suspension force for the rotor 2, which exactly counteracts the gravity of the rotor 2 itself, so that the rotor 2 can maintain a basic suspension state without current input of the control coils 4, and does not need additional energy to maintain static balance, thereby significantly reducing the standby power consumption of the system.

[0036] When the rotor 2 produces a radial displacement due to external disturbance or load change during rotation, the control coils 4 distributed on the magnetic pole groups 3 will be dynamically adjusted according to the displacement signal. Specifically, if the rotor 2 deviates in a certain direction, the control coils 4 on the magnetic pole teeth 31 in the corresponding direction will generate additional magnetic flux through current change, and the additional magnetic flux and the bias magnetic flux of the permanent magnet 33 are superimposed to enhance the attraction force on the rotor 2; while the control coils 4 in the opposite direction weaken the magnetic flux by reducing the current, forming a reverse force difference to push the rotor 2 back to the center position. In this adjustment mechanism, the first magnetic gap 30 and the second magnetic gap 32 play a key role: the first magnetic 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 gap 32 limits the magnetic flux crosstalk between the two magnetic pole teeth 31 in the same group, so that the bias magnetic flux of the permanent magnet 33 and the adjustment magnetic flux of the coil can both act on the rotor 2, reducing the leakage of invalid magnetic flux and improving the utilization efficiency of the magnetic field.

[0037] In addition, according to the accompanying drawings Figure 4As shown, the adaptation between the magnetic flux distribution and the structural design of the magnetic suspension bearing scheme can be clearly observed from the figure, and the following conclusions can be drawn:

[0038] The permanent magnet 33 forms a stable closed magnetic flux loop in the second magnetic isolation gap 32 of the bias magnetic field area. The magnetic flux extends from the N pole of the permanent magnet 33 to the rotor 2 direction through one side magnetic pole tooth 31, and then flows back to the S pole of the permanent magnet 33 through the other side magnetic pole tooth 31. This path is completely consistent with the design expectation, indicating that the N and S poles of the permanent magnet 33 are accurately matched with the two side magnetic pole teeth 31, which can effectively provide the rotor 2 with a bias suspension force against gravity, allowing the rotor 2 to maintain a basic suspension state without the current of the control coil 4, and verifying the rationality of the single-sided permanent magnet bias design.

[0039] At the same time, 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 tooth 31 and the rotor 2 area, showing a clear low magnetic flux area, indicating that the magnetic isolation gap successfully blocks the diffusion of magnetic flux to the adjacent magnetic pole group 3 or non-target area, avoiding energy waste caused by magnetic flux leakage, and concentrating the magnetic flux on the effective path of "permanent magnet 33 - magnetic pole tooth 31 - rotor 2", improving the magnetic energy utilization efficiency.

[0040] In addition, there is an adjustable magnetic flux gradient around the area where the control coil 4 is wound around the magnetic pole tooth 31. When the coil is connected with current, the dynamic magnetic flux generated by the coil can smoothly superimpose or cancel the bias magnetic flux of the permanent magnet 33. In the figure, the magnetic flux density of the corresponding area changes regularly with the current, indicating that the control coil 4 can achieve precise correction of the radial displacement of the rotor 2 through current adjustment, especially when the rotor 2 is offset due to disturbance. The coil in the corresponding direction can quickly generate directional force through magnetic flux change to push the rotor 2 back to the center position.

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

[0042] Compared with the prior art, the scheme solves multiple key problems and achieves significant technical effects. The traditional pure active magnetic bearing needs to continuously input a large initial current and bias current to the control coil 4 to resist the gravity of the rotor 2 and maintain suspension, resulting in high power consumption. The bias magnetic flux provided by the single-sided permanent magnet 33 directly offsets the gravity of the rotor 2, and almost no output current is needed for the control coil 4 in static suspension, greatly reducing the system power consumption, especially in low-speed or static operation scenarios.

[0043] The existing hybrid magnetic bearing mostly adopts a symmetrical distribution of permanent magnets 33 structure, which can balance the radial force, but still needs the control coil 4 to continuously output additional current in the vertical direction against gravity. The symmetrical distribution of permanent magnets 33 easily leads to magnetic flux leakage in non-target areas, reducing the utilization rate of magnetic energy. The scheme sets the permanent magnets 33 only in the bias magnetic field area of the stator 1 away from the gravity direction, specifically strengthens the suspension force against gravity, and cooperates with the first and second magnetic isolation gaps 32 to effectively reduce magnetic flux leakage, so that the effective suspension force is improved under the same amount of permanent magnets 33, and the magnetic energy utilization rate is significantly improved.

[0044] Embodiment 2

[0045] Based on embodiment 1, as shown in Figures 2-3 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 embedded with the first limiting groove 5 and the second limiting groove 6. Among them, 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, which is used to limit the position of the magnetic pole tooth 31 in the radial direction; the second limiting groove 6 is located at one end of the magnetic pole tooth 31 along the circumferential direction of the stator 1, which is used to limit the position of the magnetic pole tooth 31 in the circumferential direction.

[0046] Through 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, the relative position between the magnetic pole tooth 31 and the stator 1 and the rotor 2 can be ensured to be stable for a long time, thereby providing a structural basis for the reliable operation of the magnetic bearing.

[0047] Specifically, the first limiting groove 5 is located on the radial outer side of the magnetic pole tooth 31, and after being embedded 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 avoid the radial deviation of the magnetic pole tooth 31 caused by magnetic force, vibration or thermal expansion and contraction, thereby ensuring that the air gap between the magnetic pole tooth 31 and the rotor 2 always remains uniform. While the second limiting groove 6 is located at one end of the magnetic pole tooth 31 along the circumferential direction, and after being embedded with the corresponding limiting rod 7, it can limit the rotation or deviation of the magnetic pole tooth 31 along the circumferential direction of the stator 1, ensuring that the spacing between adjacent magnetic pole groups 3 and the relative position of the two magnetic pole teeth 31 within the same group remain fixed, avoiding the asymmetry of the magnetic field distribution caused by circumferential displacement.

[0048] The direct effect of this double limiting structure is reflected in the stability of the magnetic circuit: the radial position of the pole teeth 31 is stable, which ensures the uniformity of the air gap, and the uniformity of the air gap is the premise of the stability of the magnetic flux density, which means that the bias suspension force provided by the permanent magnet 33 and the adjustment force generated by the control coil 4 will not be suddenly changed due to the fluctuation of the air gap, and the radial force received by the rotor 2 is more balanced, and the suspension stability is significantly improved. At the same time, the circumferential position of the pole teeth 31 is fixed, which ensures the uniform spacing of adjacent magnetic pole groups 3, and the first magnetic gap 30 can continuously and effectively block the magnetic flux interference between groups, avoiding magnetic flux leakage or crosstalk caused by spacing changes, and the magnetic energy utilization efficiency can be maintained; the relative position of the two pole teeth 31 in the same group is stable, which also ensures the corresponding relationship between the permanent magnet 33 in the second magnetic gap 32 and the two side pole teeth 31, and ensures the smoothness of the closed loop of the bias magnetic flux, further strengthening the stability of the suspension force against gravity.

[0049] Embodiment 3

[0050] On the basis of embodiment 1, the structure of the permanent magnet 33 is improved.

[0051] As shown in Figures 5-7 In this embodiment, the permanent magnet 33 adopts a Halbach array structure composed of multiple monomers, which realizes the synergistic effect of magnetic field focusing and stable operation through the ordered arrangement and optimization of the characteristics of the permanent magnet monomers. Overall, the permanent magnet 33 is composed of a plurality of permanent magnet monomers distributed along the circumference of the stator 1 in the second magnetic gap 32, adjacent permanent magnet monomers are fixed by magnetic attraction, and the magnetization direction of the permanent magnet monomers is sequentially deflected by 90° along the circumference, forming a typical Halbach array. The core advantage of this array structure is to utilize the magnetic field superposition of adjacent monomers to make the magnetic flux spontaneously focus 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 unnecessary leakage.

[0052] Specifically, the permanent magnet monomer comprises at least three sections, in sequence, the first monomer 330, the second monomer 331 and the third monomer 332, and the three sections are of the same size and length, ensuring uniform distribution in the circumferential direction. Among them, the magnetization direction of the first monomer 330 is radially outward along the stator 1, the magnetization direction of the second monomer 331 is along the circumferential tangent direction of the stator 1, and the magnetization direction of the third monomer 332 is radially inward along the stator 1. The magnetization directions of the three monomers are sequentially deflected by 90° in the circumferential direction, meaning that the end close to the outer side of the stator 1 is N-pole, the end close to the rotor 2 side is S-pole, and the side close to the second monomer 331 in the circumferential direction presents S-pole due to the magnetic field line closure characteristic; the magnetization direction of the second monomer 331 is along the circumferential tangent direction of the stator 1 in the clockwise direction, the side on the left side in the circumferential direction is N-pole, and the side on the right side is S-pole. This tangential direction magnetization enables it to naturally receive the magnetic field of the first monomer 330 and guide the deflection thereof; the magnetization direction of the third monomer 332 is radially inward along the stator 1, the end close to the rotor 2 is N-pole, the end close to the outer side is S-pole, and the side close to the second monomer 331 in the circumferential direction presents N-pole. It is this sequential 90° deflection of the magnetization direction that causes the abutting surfaces of adjacent monomers to form a strict pole correspondence: the S-pole side of the first monomer 330 is opposite to the N-pole side of the second monomer 331, and the S-pole side of the second monomer 331 is opposite to the N-pole side of the third monomer 332. According to the basic characteristic of the magnet that "opposite poles attract", a continuous and stable magnetic attraction force is generated between adjacent monomers. This force, combined with the physical adhesion of the non-magnetic glue layer, not only effectively prevents the monomers from loosening and shifting under the action of vibration or magnetic field force, but also avoids the magnetic flux shunting problem that may be caused by the use of magnetic material fixation, ensuring the integrity of the magnetic field path.

[0053] At the same time, through the arrangement structure of the three monomers, the orthogonality of the array is ensured, and through the combination of radial and tangential magnetization, the magnetic flux is guided by the tangential direction of the second monomer 331 after starting from the first monomer 330, and finally converges inward by the third monomer 332, forming a strengthened magnetic flux path pointing to the rotor 2.

[0054] At the same time, soft magnetic sheets 8 of silicon steel material can be additionally arranged between the abutting surfaces of adjacent monomers, which utilizes the high magnetic permeability of soft magnetic material to reduce the magnetic resistance of the abutting surface, promotes the smooth transmission of the magnetic field between the monomers, and further reduces the magnetic flux loss.

[0055] In addition, the residual magnetic density of the second monomer 331 is designed to be greater than that of the first monomer 330 and the third monomer 332. This is because the second monomer 331, as the core component magnetized in the tangential direction, plays a key role in guiding the radial magnetic flux to turn and strengthening the magnetic flux superposition on the rotor 2 side. Higher residual magnetic density can enhance the magnetic field strength in the tangential direction, form a stronger synergy with the magnetic field of the radial monomer, and further improve the effective magnetic flux density on the rotor 2 side.

[0056] Compared with embodiment 1, this embodiment is improved by the permanent magnet 33 of the multi-monomer Halbach array structure, which specifically solves the core problems of low magnetic flux utilization efficiency, insufficient suspension force stability, limited control response sensitivity, etc. in the original scheme, and realizes better operation performance. The specific reasons and effects are as follows:

[0057] Firstly, the problem of uneven magnetic flux distribution and serious leakage of single permanent magnet 33 is solved, and the effective magnetic flux density on the rotor 2 side is significantly improved. Although the single permanent magnet 33 in embodiment 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 transferring to the rotor 2 side, resulting in a large amount of magnetic energy wasted in the non-effective path. The actual magnetic flux density obtained on the rotor 2 side is limited. While the Halbach array of this embodiment deflects the magnetization direction of the three single bodies by 90° in turn, and uses the principle of magnetic field superposition to make the magnetic flux focus on the rotor 2 side: the radial magnetic flux of the first single body 330 is guided by the circumferential magnetic field of the second single body 331, and the radial inward magnetic flux of the third single body 332 forms superposition on the rotor 2 side, while the magnetic flux on the outside of the stator 1 is greatly weakened due to the direction offset. This focusing effect directly reduces the magnetic flux leakage, significantly improves the effective magnetic flux density on the rotor 2 side, and further enhances the bias suspension force provided by the permanent magnet 33, because the suspension force is proportional to the square of the magnetic flux density. Higher effective magnetic flux density directly translates into stronger ability to resist gravity, so even if the rotor 2 load fluctuates slightly, it can still be stably suspended.

[0058] Secondly, the problem of poor magnetic flux stability of single permanent magnet 33 and easy to be affected by mechanical vibration is solved, and the long-term operation reliability is improved. In embodiment 1, the single permanent magnet 33 is fixed in the second magnetic gap 32 by mechanical structure, which is easily affected by the vibration of the rotor 2 and the fluctuation of the magnetic pull in long-term operation, and is prone to slight loosening, which leads to the relative position deviation between the permanent magnet 33 and the magnetic pole tooth 31, and further causes the distortion of the magnetic flux path and the fluctuation of the suspension force. While in this embodiment, the adjacent permanent magnet monomers are fixed by heteropolar magnetic attraction and non-magnetic adhesive layer: the magnetic attraction force of the heteropolar contact surface forms a continuous self-tightening force, which cooperates with the physical adhesion of the non-magnetic adhesive layer to keep the relative position accuracy between the permanent magnet 33 and the magnetic pole tooth 31 within a very small range, so that the permanent magnet 33 is not easily loosened even in long-term vibration. At the same time, the silicon steel soft magnetic sheet 8 added to the contact surface reduces the magnetic resistance between the monomers, avoiding the magnetic flux mutation caused by the small gap, and further ensuring the stability of the magnetic flux. This structure significantly reduces the fluctuation amplitude of the suspension force compared with embodiment 1, and reduces the rotor 2 micro-vibration phenomenon caused by unstable magnetic flux from the root.

[0059] In addition, the problem of insufficient dynamic adjustment sensitivity of the control coil 4 is solved, and more accurate displacement correction is realized. In embodiment 1, the magnetic flux distribution of the single permanent magnet 33 has certain nonlinearity, and the magnetic flux density decreases rapidly near the edge, resulting in unstable magnetic flux superposition effect when the control coil 4 passes current, the relationship between current and suspension force is nonlinear, and overshoot or lag is prone to occur when adjusting the displacement of the rotor 2. In this embodiment, the Halbach array makes the magnetic flux distribution on the rotor 2 side more uniform, the difference in magnetic flux density at each point in the radial direction is reduced, and because the magnetic flux is focused to the rotor 2 side, the dynamic magnetic flux generated by the control coil 4 can be more efficiently superimposed or offset with the bias magnetic flux to significantly improve control accuracy. For example, when the rotor 2 deviates in a certain direction, only a small current needs to be passed through the corresponding coil, and sufficient correction force can be generated through magnetic flux superposition, the response speed is significantly faster than that of embodiment 1, and the stability of the rotor 2 is effectively improved.

[0060] Finally, further optimization is realized in energy consumption control. In embodiment 1, the single permanent magnet 33 has magnetic flux leakage, and in order to maintain sufficient suspension force, the control coil 4 needs to pass additional current to compensate for the lack of magnetic flux, which indirectly increases power consumption. While the permanent magnet 33 of this embodiment focuses and reduces the magnetic resistance, the compensation current of the control coil 4 can be significantly reduced under the same suspension force requirement; at the same time, the more stable magnetic flux allows the coil to not need to adjust the current size frequently, further reducing the dynamic power consumption. This idea of replacing current compensation with magnetic circuit optimization reduces the overall system energy consumption compared to embodiment 1, and is particularly suitable for high-speed rotating scenarios with strict low-power requirements.

[0061] The same or similar reference numerals in the drawings of the present embodiment correspond to the same or similar components; in the description of the present application, it should be understood that the orientations or positional relationships indicated by terms such as "upper", "lower", "left", "right" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the terms describing the positional relationship in the drawings are only used for exemplary illustration, and cannot be understood as a limitation of the present patent, for those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0062] The above is only a preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A magnetic bearing based on unilateral permanent magnet bias, comprising a stator (1) and a rotor (2), characterized in that: A plurality of magnetic pole groups (3) arranged on the stator (1) are provided between the stator (1) and the rotor (2), the plurality of magnetic pole groups (3) being equidistantly distributed on the stator (1) and a first magnetic isolation gap (30) being provided between adjacent magnetic pole groups (3); each group of the magnetic pole groups (3) comprising two magnetic pole teeth (31) wound with a control coil (4), a second magnetic isolation gap (32) being provided between two adjacent magnetic pole teeth (31); and a permanent magnet (33) being provided in the second magnetic isolation gap (32), the permanent magnet (33) being located above the rotor (2) and being used to provide the rotor (2) with a levitation force against gravity.

2. A magnetic bearing based on unilateral permanent magnet bias according to claim 1, characterized in that: With the direction of gravity as a reference, the half region of the stator (1) facing away from the direction of gravity is a bias magnetic field region, and the permanent magnet (33) is arranged in a second magnetic isolation gap (32) in the bias magnetic field region.

3. The magnetic bearing based on unilateral permanent magnet bias according to claim 2, characterized in that: The permanent magnet (33) comprises an N pole and an S pole, and the N pole and the S pole of the permanent magnet (33) correspond to the magnetic pole teeth (31) on both sides respectively.

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

5. The magnetic 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. The magnetic bearing based on unilateral permanent magnet bias according to claim 4, characterized in that: The permanent magnet (33) is composed of a plurality of permanent magnet monomers that are magnetically fixed to each other, and the plurality of permanent magnet monomers are distributed in the second magnetic isolation gap (32) along the circumference of the stator (1), and the magnetization directions of adjacent permanent magnet monomers are sequentially deflected by 90 degrees along the circumference to form a Halbach array structure.

7. The magnetic bearing based on unilateral permanent magnet bias according to claim 6, characterized in that: The permanent magnet monomer has at least three sections, including a first monomer (330), a second monomer (331) and a third monomer (332) arranged in sequence, wherein the magnetization direction of the first monomer (330) is radially outward of the stator (1), the magnetization direction of the second monomer (331) is along the circumferential tangent direction of the stator (1); and the magnetization direction of the third monomer (332) is radially inward of the stator (1).

8. The magnetic bearing based on unilateral permanent magnet bias according to claim 7, characterized in that: The three permanent magnet monomers are of equal size and length, and the magnetic poles of adjacent permanent magnet monomers are opposite in polarity, and are adhered and fixed by a non-magnetic adhesive layer.

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

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

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