Three-degree-of-freedom target disc type vertical hybrid magnetic bearing structure

Abstract

This invention relates to a three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure, including a stator assembly and a rotor assembly. The stator assembly includes a mounting plate and a multi-pole shoe electromagnetic circuit assembly. The multi-pole shoe electromagnetic circuit assembly includes a magnetic yoke, from which multiple pole shoes extend. Several of the multi-pole shoe electromagnetic circuit assemblies are evenly distributed at equal angles on the mounting plate. The mounting plate is fixed to an external support structure and has a circular hole at its center. The rotor assembly includes a rotating shaft and a rotor magnetic disk, which are fixed as a single unit. One side of the rotor magnetic disk has multiple concentric annular magnetic teeth that are aligned with each pole shoe. The rotating shaft passes vertically through the circular hole and is adapted to fit the circular hole. A block-shaped permanent magnet is also fixed at each pole shoe; or, an annular permanent magnet is provided in the gap between adjacent annular magnetic teeth.

Description

Technical Field

[0001] This invention relates to a magnetic levitation bearing, specifically a target-disc type permanent magnet bias-electromagnetic adjustment hybrid excitation magnetic levitation bearing structure, belonging to the field of magnetic levitation bearing technology. Background Technology

[0002] Existing active magnetic levitation bearings are mostly designed around the axial load-bearing unit of "thrust disk-stator magnetic poles," improving load-bearing capacity and efficiency through methods such as optimizing magnetic circuit shape, introducing bias magnetic flux, or adopting axial-radial integration. Although these improvements have achieved certain results in reducing eddy current losses and shortening axial dimensions, they still generally suffer from engineering bottlenecks such as a large number of actuators and magnetic pole components, complex magnetic circuits and assembly topologies, sensitivity to air gap consistency and coaxiality, difficulty in further miniaturization, and strong dependence on displacement detection accuracy and multi-channel high-bandwidth closed-loop control.

[0003] While existing permanent magnet-electromagnetic hybrid excitation magnetic levitation bearings and related active magnetic levitation support solutions can provide bias flux through permanent magnets and achieve dynamic adjustment through electromagnetic coils, they still have significant shortcomings when applied to compact integration applications for small-diameter shafts and miniaturized rotating machinery. On the one hand, to improve reliability or avoid adsorption risks, many solutions rely on additional mechanical limiting mechanisms or separate radial and axial support units, leading to an increase in the number of structural components, complex assembly paths, and higher precision requirements such as coaxiality. This makes it difficult to further reduce volume and axial footprint, limiting system integration and engineering feasibility. On the other hand, in traditional magnetic circuit arrangements, permanent magnets are often far from the working air gap or have long magnetic circuit paths, easily causing leakage flux and increased magnetic reluctance, thus affecting the effective magnetic flux density of the air gap. Limited magnetic flux utilization makes it difficult to achieve higher thrust density and load-bearing capacity within the constraints of limited disk size. Meanwhile, many solutions still require continuous bias current to establish the working magnetic field, resulting in high steady-state power consumption and temperature rise. Thermal drift can easily lead to air gap changes and levitation force fluctuations, affecting energy efficiency and long-term stability. Furthermore, the radial constraint capability of target disk / thrust disk structures is generally insufficient. Existing technologies often compensate by adding independent radial magnetic bearings, increasing control channels, or employing complex collaborative control, further increasing system complexity and cost and weakening miniaturization adaptability. On this basis, a small levitation air gap is often required to obtain sufficient electromagnetic force, making the system more sensitive to machining and assembly errors, sensor noise, and control robustness, increasing the risk of wear and tear under vibration or disturbance conditions.

[0004] Prior art citations:

[0005] Publication date: 2018-03-16, Publication number: CN207111711U, Subject: "A coaxial electromagnet structure for thrust magnetic bearing";

[0006] Publication date: 2019-05-03, Publication number: CN109707735A, Subject: "Magnetic bearings";

[0007] Publication date: 2015-01-07, Publication number: CN104265761A, Subject: "A hybrid magnetic bearing with axial-radial three degrees of freedom";

[0008] Publication date: March 10, 2010; Publication number: CN101666353A; Subject: “Active magnetic bearing with radial-axial shared bias magnetic flux and its control method”. Summary of the Invention

[0009] To address the shortcomings of existing permanent magnet-electromagnetic hybrid excitation magnetic levitation bearings in small-diameter shafts and miniaturized rotating machinery applications, such as insufficient structural integration, high power consumption and temperature rise due to steady-state bias current, limited magnetic flux utilization and thrust density within compact spaces, and insufficient radial passive centering capability of target-disc type structures often requiring additional radial bearings / control channels, this invention proposes a target-disc type permanent magnet bias-electromagnetic regulation hybrid excitation magnetic levitation bearing structure. By placing permanent magnets at key positions in the magnetic circuit near the working air gap to provide bias flux, and using electromagnetic coils to enhance / weaken the bias flux, the system significantly reduces the steady-state coil bias current requirement near equilibrium, reducing copper loss heating and thermal drift effects. Simultaneously, the magnetic reluctance effect of the "stator pole shoe-rotor multi-turn concentric annular magnetic teeth" provides radial passive centering stiffness. Under certain application conditions, this reduces dependence on independent radial magnetic bearings and their control channels, and supports multi-level module series connection to expand load-bearing capacity without increasing rotor diameter, thus meeting the requirements for miniaturization, compact integration, and high-stability levitation support.

[0010] The present invention adopts the following technical solution:

[0011] A three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure includes a stator assembly 1 and a rotor assembly 2. The stator assembly 1 includes a mounting plate 11 and a multi-pole shoe type electromagnetic circuit assembly 12. The multi-pole shoe type electromagnetic circuit assembly 12 includes a magnetic yoke 121, from which multiple pole shoes are led out from one side. Several of the multi-pole shoe type electromagnetic circuit assemblies 12 are evenly distributed on the mounting plate 11 at equal angles. The mounting plate 11 is fixed to an external support structure and has a circular hole at its center. The rotor assembly 2 includes a rotating shaft 21 and a rotor magnetic disk 22, which are fixed as one unit. The rotor magnetic disk 22 has multiple concentric annular magnetic teeth on one side, which are aligned with the pole shoes one by one. The rotating shaft 21 passes vertically through the circular hole and is adapted to the circular hole. A block-shaped permanent magnet is also fixed at each pole shoe. Alternatively, an annular permanent magnet is provided in the gap between adjacent annular magnetic teeth.

[0012] Preferably, the permanent magnets are fixedly disposed at the lower end of each pole piece in a one-to-one correspondence.

[0013] Preferably, the permanent magnet is fixed to the side of the pole shoe with opposite magnetic poles.

[0014] Preferably, the multi-pole shoe-type electromagnetic circuit assembly 12 is a U-shaped electromagnet, and the corresponding rotor magnetic disk 22 has two annular magnetic teeth, one inside and one outside.

[0015] Preferably, the multi-pole shoe-type electromagnetic circuit assembly 12 is an E-type electromagnet, and the corresponding rotor magnetic disk 22 has three annular magnetic teeth: inner, middle, and outer.

[0016] Preferably, the mounting plate 1 is rectangular.

[0017] Preferably, each of the pole shoes is provided with a coil, and the multi-pole shoe electromagnetic circuit assembly 12 generates an attractive force on the rotor magnetic disk 22.

[0018] Preferably, a plurality of rotor aggregate disks 22 with the same orientation are integrally fixed on the rotating shaft 21 of the rotor assembly 2, and each rotor aggregate disk 22 corresponds to a different stator assembly 1.

[0019] Preferably, the rotor magnetic disk 22 is provided with the annular magnetic teeth on both sides, and the annular magnetic teeth on both sides correspond to the stator assembly 1. The function of the stator assembly 1 located at the lower part is to balance the load size, obtain bidirectional thrust bearing capacity or improve the anti-overturning capacity.

[0020] Preferably, each pole piece of the multi-pole shoe electromagnetic circuit assembly 12 has a concave side and a convex side, and the curvature of the concave side and the convex side corresponds to the curvature of the corresponding annular magnetic tooth.

[0021] The beneficial effects of this invention are as follows:

[0022] 1) Reduce steady-state bias current and temperature rise: The permanent magnet provides the main bias flux required to bear the static load of the rotor, and the electromagnetic coil is only used for modulation and disturbance rejection control, which significantly reduces the steady-state coil current near the equilibrium, thereby reducing copper loss and heat generation and weakening the impact of thermal drift on the stability of the air gap and levitation force.

[0023] 2) Improve magnetic flux utilization and thrust density in a compact space: Permanent magnets are arranged in key positions of the magnetic circuit near the working air gap to shorten the magnetic circuit and reduce magnetic leakage and magnetic resistance; in conjunction with multi-turn concentric ring magnetic teeth to form a distributed magnetic flux channel, the effective working area and air gap magnetic density are increased under the condition of limited target disk diameter, thereby improving axial load capacity.

[0024] 3) Enhanced radial self-stabilization and integration: Utilizing the magnetoresistive effect of "stator pole shoe - rotor annular magnetic teeth", a restoring force pointing towards the center is generated when the rotor is radially offset, forming radial passive centering stiffness; under certain application conditions, the configuration of independent radial support units and control channels can be reduced, thereby reducing the system hardware complexity and cost.

[0025] 4) Modular extended load capacity: By arranging multi-stage target-type thrust disks and multi-layer stator components in series, the axial suspension force is superimposed, which increases the load capacity and enhances the radial passive centering stiffness without increasing the rotor diameter, thus adapting to the high load capacity requirements of small-diameter shaft systems.

[0026] 5) Engineering feasibility: The stator core and coil structure adopt conventional lamination and winding processes, the rotor magnetic teeth have regular ring geometry, and the permanent magnets are regular block / ring parts, which facilitates processing, assembly and mass production.

[0027] 6) The rotor-type active magnetic levitation bearing is constructed by setting a multi-pole shoe-type electromagnetic circuit assembly on the stator side (the magnetic end part can be a two-pole, three-pole or multi-pole structure, and the electromagnet shape is not limited to U-shaped, but can also be E-shaped and other equivalent multi-end magnetic circuit structures), and constructing concentric annular magnetic teeth (inner ring, outer ring and expandable multi-ring magnetic teeth) on the rotor-type magnetic disk that match the number and distribution of the end magnetic poles. This allows each end magnetic pole to form a "multi-end-multi-ring" magnetic focusing circuit with the corresponding annular magnetic teeth. Mechanistically, this causes the excitation magnetic flux to concentrate and close at each ring tooth, improving the effective magnetic flux utilization rate and generating controllable axial electromagnetic bearing attraction, thereby obtaining stable and effective non-contact thrust support capability with a smaller structural size.

[0028] 7) Based on the principle of shortest magnetic circuit, when the rotor magnetic disk deflects radially relative to the stator, the air gap distribution between each ring tooth and the end magnetic pole will exhibit an asymmetrical change. The magnetic flux will automatically deflect to the path with lower equivalent magnetic resistance, causing the electromagnetic force to generate a radial component, forming a radial restoring constraint force pointing towards the equilibrium position. This passively limits the radial deflection and improves the disturbance rejection capability. Since the axial load and radial constraint are generated synchronously by the same set of "end multi-pole electromagnet - concentric multi-ring magnetic tooth" magnetic circuit, this invention, in the context of vertical bearing structure applications, can reduce the dependence on independent radial magnetic bearing units, or reduce the number of radial control channels and the degree of freedom required for control while meeting basic stability and load requirements. This directly brings about technical effects such as a reduction in the number of components and assembly calibration steps, a decrease in system size and manufacturing cost, and a reduction in the difficulty of control parameter tuning and engineering implementation.

[0029] 8) The rigid connection between the disk and the shaft and the contactless support can significantly reduce mechanical friction and wear, reduce lubrication requirements, and thus improve reliability and service life under high-speed conditions. It is especially suitable for integrated applications of small-diameter vertical shafts and miniaturized vertical rotating machinery. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of an embodiment of the three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure of the present invention.

[0031] Figure 2 This is a schematic diagram of the stator assembly in one embodiment.

[0032] Figure 3 This is a schematic diagram of the structure of a multi-pole shoe-type electromagnetic circuit assembly in one embodiment (U-shaped electromagnet, permanent magnet not shown).

[0033] Figure 4 This is a schematic diagram of the structure of a multi-pole shoe type electromagnetic circuit assembly in another embodiment (E-type electromagnet, the permanent magnet is shown at the end of the pole shoe).

[0034] Figure 5 This is a schematic diagram of the structure of a multi-pole shoe electromagnetic circuit assembly in another embodiment (U-shaped electromagnet, permanent magnet is shown on the side of the pole shoe).

[0035] Figure 6 This is a schematic diagram of the structure of a multi-pole shoe electromagnetic circuit assembly in another embodiment (E-type electromagnet, with the permanent magnet shown on the side of the pole shoe).

[0036] Figure 7 This is a schematic diagram of the rotor assembly.

[0037] Figure 8 This is a schematic diagram of the rotor-type magnetic disk structure in one embodiment (excluding the annular permanent magnet).

[0038] Figure 9 This is a schematic diagram of the rotor-type magnetic disk (including a ring-shaped permanent magnet) in another embodiment.

[0039] Figure 10 This is a schematic diagram showing the relative positional relationship between the U-shaped electromagnet and the rotor disk.

[0040] Figure 11 This is a schematic diagram of a two-stage concentric three-degree-of-freedom target disk-type vertical hybrid magnetic levitation bearing structure.

[0041] Figure 12 This is a schematic diagram of a three-stage (multi-stage) concentric three-degree-of-freedom target disk vertical hybrid magnetic levitation bearing structure.

[0042] Figure 13 This is a schematic diagram of a two-way, three-degree-of-freedom target-disc vertical hybrid magnetic levitation bearing structure.

[0043] Figure 14 This is a schematic diagram of a three-degree-of-freedom system that requires active control.

[0044] In the picture:

[0045] 1. Stator assembly; 2. Rotor assembly;

[0046] 11. Mounting plate; 12. Multi-pole shoe type electromagnetic circuit assembly; 121. Magnetic yoke; 123. 124. 125. Multiple different pole shoes; 126. 127. 128. Block electromagnet;

[0047] 21. Shaft; 22. Rotor magnetic disk; 221. Outer annular magnetic disk; 222. Inner annular magnetic disk; 223. Annular permanent magnet. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0049] To address the shortcomings of existing permanent magnet-electromagnetic hybrid excitation magnetic levitation bearings in small-diameter shafts and miniaturized rotating machinery applications, such as insufficient structural integration, high power consumption and temperature rise due to steady-state bias current, limited magnetic flux utilization and thrust density in compact spaces, and insufficient radial passive centering capability of target-disc type structures requiring additional radial bearings / control channels, this invention proposes a target-disc type permanent magnet bias-electromagnetic regulation hybrid excitation magnetic levitation bearing structure. This invention provides bias flux by placing permanent magnets at key positions in the magnetic circuit near the working air gap, and uses electromagnetic coils to enhance / weaken the bias flux. This significantly reduces the steady-state coil bias current requirement near equilibrium, minimizing copper loss heating and thermal drift. Simultaneously, it utilizes the reluctance effect of the "stator pole shoe-rotor multi-turn concentric annular magnetic teeth" to provide radial passive centering stiffness. Under certain application conditions, this reduces dependence on independent radial magnetic bearings and their control channels, and supports multi-level module series connection to expand load-bearing capacity without increasing rotor diameter, thus meeting the requirements for miniaturization, compact integration, and high-stability levitation bearings.

[0050] This structure introduces permanent magnets at key locations where the magnetic flux of the stator electromagnet is concentrated and / or at the grooves of the rotor target-type thrust disk. The bias magnetic flux generated by the permanent magnets and the control magnetic flux generated by the electromagnetic coils are superimposed and modulated within the working air gap, thereby reducing dependence on continuous bias current and improving magnetic flux utilization efficiency near equilibrium. The stator multi-pole pole shoe end face and the rotor multi-turn concentric annular magnetic teeth form a distributed magnetic flux channel to obtain axial mixed levitation force and form radial passive centering constraint based on the principle of minimum magnetic reluctance. This structure can significantly reduce levitation maintenance power consumption, reduce dependence on high-power control current, and improve load-bearing capacity within a compact volume through the series connection of multi-stage bearing modules.

[0051] In a traditional five-degree-of-freedom magnetic levitation bearing, there are five degrees of freedom: translational degrees of freedom along the X, Y, and Z axes, and rotational (tilting) degrees of freedom around the X and Y axes.

[0052] See Figure 14 The "three degrees of freedom" proposed in this application excludes the passively controlled translational degrees of freedom along the X and Y axes, leaving only the translational degree of freedom along the Z axis and the rotational (tilting) degrees of freedom around the X and Y axes. These three degrees of freedom require active control.

[0053] In actual magnetic levitation bearings, the magnetic disk may tilt due to external interference. At this time, active control technology is required to balance the magnetic disk. While controlling the Z-axis suspension gap, it is also necessary to prevent tilting in the X and Y axes.

[0054] Specifically, a dual closed-loop control strategy involving both gap and current is employed. Taking three electromagnets as an example, firstly, a target value for the Z-axis suspension gap is set in the controller. Secondly, the distances (called suspension gaps) between the three electromagnets and the disk are sampled in real time using three displacement sensors to obtain the actual values ​​of the suspension gaps for each electromagnet. Then, based on the target and actual values, closed-loop control of the suspension gaps can be achieved using PID, state feedback, active disturbance rejection, or other control algorithms. Furthermore, due to the inductive effect of the electromagnet coils, a current inner loop is introduced to avoid deterioration in control performance caused by the inductive effect. The current inner loop often uses a PID control algorithm to accelerate the response speed of the electromagnet coil current and weaken the adverse effects of the inductive effect on the control performance. (This is known at the principle level.)

[0055] How to achieve anti-tilt: When the aggregate disk tilts around the X-axis and / or Y-axis, the actual value of the suspension gap corresponding to the electromagnet will deviate from the target value due to the tilt. When the actual value of the suspension gap corresponding to a certain electromagnet is greater than the set target value, the control algorithm will adjust the coil current of that electromagnet to reduce the actual value of the suspension gap between that electromagnet and the aggregate disk. Similarly, when the actual value of the suspension gap corresponding to a certain electromagnet is less than the set target value, the control algorithm will adjust the coil current of that electromagnet to increase the actual value of the suspension gap between that electromagnet and the aggregate disk. Ultimately, under the action of the gap and current dual closed-loop control strategy, the actual values ​​of the suspension gaps corresponding to the three electromagnets will stabilize near the set suspension gap target values. At this time, the aggregate disk restores balance, and the tilt is suppressed.

[0056] For ease of understanding, this embodiment provides a rotor-disk type active magnetic levitation bearing structure, which includes: stator assembly 1 and rotor assembly 2.

[0057] (a) Stator assembly 1:

[0058] The stator assembly 1 is used to provide hybrid excitation levitation force, and includes a stator base 11 and several sets of multi-pole shoe electromagnetic circuit assemblies 12 fixed on the base.

[0059] The stator base 11 is a plate-shaped or ring-shaped structure used to support and position each multi-pole shoe-type electromagnetic circuit assembly 12.

[0060] The multi-pole shoe electromagnetic circuit assembly 12 is evenly distributed along the circumference of the stator base 11. Preferably, three sets of multi-pole shoe electromagnetic circuit assemblies 12 can be evenly distributed at 120° intervals along the circumference, or four sets can be evenly distributed at 90° intervals, etc., in a symmetrical layout to form a stable three-point or multi-point support plane.

[0061] The multi-pole shoe-type electromagnetic circuit assembly 12 includes a stator core 121, an excitation coil 122 wound on the stator core 121, and a permanent magnet assembly located at a key position in the magnetic circuit.

[0062] Core structure: The stator core 121 can be a U-shaped structure (with two magnetic pole arms) or an E-shaped / triple structure (with three magnetic pole arms, corresponding to the target disk action areas of the inner ring, middle ring and outer ring).

[0063] Permanent magnet configuration: To form a permanent magnet bias flux, the permanent magnet may be disposed at at least one of the following locations:

[0064] Interpole permanent magnet 129: disposed between the pole arms of a U-shaped or E-shaped iron core to provide the main bias magnetic flux; such as Figure 5 and Figure 6 As shown;

[0065] Permanent magnet pole shoes 126, 127, and 128: These are located at the ends of the pole arms. The inner ring permanent magnet pole shoe 126, the outer ring permanent magnet pole shoe 127, and the intermediate permanent magnet pole shoe 128 (suitable for E-type structures) are opposite to the rotor target disk to increase the magnetic flux density in the air gap. Figure 4 As shown.

[0066] (When used in conjunction with the permanent magnet in the rotor side groove) it can also form a more efficient hybrid excitation magnetic circuit together with the permanent magnet in the thrust disk groove, such as Figure 8 As shown.

[0067] Coil configuration: The excitation coil 122 is wound on the pole arm of the stator core 121; after being energized, it generates a control magnetic flux, which is used to enhance or weaken the combined magnetic flux density of the permanent magnet bias flux in the air gap, thereby realizing the adjustable control of the levitation force.

[0068] (ii) Rotor assembly 2

[0069] like Figure 7 The rotor assembly 2 is a suspended component, including a rotating shaft 21 and a rotor disk 22 fixed on the rotating shaft 21.

[0070] The rotor magnetic focusing disk 22 is a disk body with a magnetically conductive texture. Its surface is provided with several concentric annular magnetic focusing teeth, forming a working air gap with the stator side pole shoes in the axial direction. The annular magnetic focusing teeth include at least:

[0071] Outer ring tooth 221: corresponds to stator outer ring magnetic pole / pole shoe 127 / 124.

[0072] Inner ring tooth 222: corresponds to stator inner ring magnetic pole / pole shoe 126 / 123.

[0073] like Figure 8 Optional permanent magnets at the grooves of the rotor disk 22: Annular permanent magnets 223 can be embedded in the grooves between the outer annular teeth 221 and the inner annular teeth 222, and / or in other annular grooves of the thrust disk. The annular permanent magnets 223 rotate synchronously with the rotor, and their magnetization direction can be axial or radial, to provide a constant permanent magnet bias flux to the air gap and stator circuit according to the specific magnetic circuit design.

[0074] The rotor-side annular magnetic concentrating teeth (such as 221 and 222) match the stator-side pole shoes in the radial direction, forming a working air gap in the axial direction. The multi-concentric ring structure can increase the effective working area of ​​the magnetic circuit, thereby improving the axial load-bearing capacity under the condition of limited disk diameter.

[0075] like Figure 3 and Figure 4 Each pole piece of the multi-pole-shoe electromagnetic circuit assembly 12 has a concave side and a convex side, and the curvature of the concave and convex sides corresponds to the curvature of the corresponding annular magnetic teeth. Essentially, this is to ensure that when there is no radial offset in the rotor, a portion of the pole piece and a portion of the annular magnetic teeth can be perfectly aligned (coincident). The advantage of this is that when a slight radial offset occurs, the area of ​​the pole piece and the annular magnetic teeth facing each other changes significantly, thereby improving the radial passive constraint capability.

[0076] (III) Magnetic circuit coupling and working principle

[0077] This invention adopts a hybrid excitation working mode of "permanent magnet bias - electromagnetic adjustment".

[0078] Axial levitation (active control): Permanent magnets (such as 129 and / or 126-128 and / or 223) generate permanent magnet bias flux. The bias flux enters the annular magnetic teeth of the rotor target disk through the stator core and working air gap and forms a closed magnetic circuit, thereby providing the main static levitation force to support the rotor's own weight and part of the load. Near the equilibrium, the steady-state coil bias current can be significantly reduced.

[0079] When it is necessary to adjust the axial position or resist disturbances, the controller drives the excitation coil 122 to output current to generate control flux. The control flux is superimposed with the permanent magnet bias flux and changes the air gap magnetic flux density, thereby realizing the precise adjustment and stable control of the axial suspension force.

[0080] Radial constraint (passive alignment): Based on the principle of minimum magnetic reluctance, the stator pole shoes and rotor annular magnetic teeth tend to maintain concentric alignment. When the rotor target disk 22 experiences radial offset, the change in the effective overlap area between the pole shoes and the annular magnetic teeth leads to uneven magnetic reluctance and deflection of the magnetic field line distribution, thereby generating a radial restoring force pointing towards the center, providing radial passive alignment stiffness; under the application conditions that meet the design magnetic flux density and structural parameters, the dependence on independent radial magnetic bearings and their control channels can be reduced.

[0081] (iv) Extended structure of multi-stage bearing modules in series

[0082] like Figure 11 To accommodate small-diameter shafts or higher load requirements, the structure of this invention has axial scalability:

[0083] like Figure 12 Two or more rotor aggregate disks 22 can be arranged axially at intervals on the same rotating shaft 21 to form a series configuration of multi-stage bearing modules such as two-stage or three-stage.

[0084] Accordingly, the stator system is provided with multiple stator assemblies 1 along the axial direction, and each stator assembly 1 works synchronously with the corresponding rotor disk 22;

[0085] The axial mixed suspension forces generated at each stage are superimposed on the rotating shaft 21, thereby multiplying the axial load-bearing capacity without increasing the rotor diameter, and simultaneously enhancing the radial passive centering stiffness.

[0086] (v) Control System

[0087] The target-disc hybrid excitation magnetic levitation bearing structure can be combined with a displacement sensor, power amplifier, and controller to form a closed-loop control system. The displacement sensor is used to detect changes in the axial clearance of the target disc, and the controller adjusts the direction and magnitude of the current in the excitation line according to the detected deviation, thereby adjusting the combined magnetic field force to achieve stable levitation of the rotor at the equilibrium position. To avoid excessive suction or assembly magnetization risks under shutdown / power failure conditions, engineering constraints can be implemented through magnetic circuit bypass design, current limiting strategies, material selection (such as high coercivity permanent magnets), or the installation of non-magnetic isolation / shielding components.

[0088] The target-disc type permanent magnet bias-electromagnetic regulation hybrid excitation magnetic levitation bearing structure provided by this invention constructs a hybrid excitation coupling magnetic circuit of "stator multi-pole electromagnet unit - rotor target-type thrust disk (ring-shaped magnetic teeth)", so that the permanent magnet bias flux and the electromagnetic control flux are superimposed and modulated in the working air gap. This overcomes the problems of high power consumption, difficulty in compression, and insufficient radial stability in the prior art at the structural mechanism level, and achieves the following technical effects:

[0089] 1) Low power consumption and temperature rise suppression: Permanent magnets are introduced at key locations in the hybrid excitation magnetic circuit (such as rotor grooves and / or stator pole shoe ends) to provide the main bias flux to support the rotor's self-weight and static load; the electromagnetic coils only output control flux for dynamic adjustment, thereby reducing the continuous current required to maintain suspension, reducing copper loss and heat generation, and mitigating the adverse effects of thermal drift caused by temperature rise on the air gap and suspension accuracy.

[0090] 2) Load-bearing capacity enhancement and miniaturization adaptation in compact space: The stator side U-shaped, E-shaped or multi-pole pole shoes are set opposite to the rotor side multi-turn concentric ring magnetic teeth to form a distributed magnetic flux channel, which improves the magnetic flux convergence and utilization efficiency in the air gap, and enhances the axial suspension force output capability without significantly increasing the outer diameter, which is conducive to balancing thrust density and structural miniaturization.

[0091] 3) Radial passive alignment and system simplification: Utilizing the magnetoresistive effect of the "stator pole shoe - rotor annular magnetic teeth", an asymmetric magnetic flux distribution is generated when the rotor is radially offset, forming a radial restoring force pointing towards the center, thus achieving radial passive alignment constraint; combined with permanent magnet bias to improve air gap magnetic flux density, the passive stiffness and disturbance rejection capability can be enhanced, thereby reducing the dependence on independent radial bearings and radial control channels, simplifying the hardware and control system and reducing costs.

[0092] In summary, this invention achieves low power consumption, high integration, and miniaturization adaptability through the collaborative design of a hybrid excitation magnetic circuit of "permanent magnet bias-electromagnetic adjustment" and a target disk-type ring magnetic focusing structure, while also improving radial stability and engineering feasibility.

[0093] The above are preferred embodiments of the present invention. Those skilled in the art can make various modifications or improvements based on these embodiments. Without departing from the overall concept of the present invention, such modifications or improvements should fall within the scope of protection claimed by the present invention.

Claims

1. A three-degree-of-freedom target-disc type vertical hybrid magnetic levitation bearing structure, characterized in that: Includes stator assembly (1) and rotor assembly (2); The stator assembly (1) includes a mounting plate (11) and a multi-terminal pole shoe electromagnetic circuit assembly (12). The multi-pole shoe electromagnetic circuit assembly (12) includes a magnetic yoke (121), from which multiple pole shoes are led out from one side; several of the multi-pole shoe electromagnetic circuit assemblies (12) are evenly distributed on the mounting plate (11) at equal angles; the mounting plate (11) is fixed on the external support structure, and a circular hole is provided in its center; The rotor assembly (2) includes a rotating shaft (21) and a rotor magnetic disk (22), which are fixed together. The rotor magnetic disk (22) has a plurality of concentric annular magnetic teeth on one side, which are aligned with the pole shoes one by one. The rotating shaft (21) passes vertically through the circular hole and is adapted to the circular hole. Each of the pole shoes is also fixedly provided with a block-shaped permanent magnet; or, an annular permanent magnet is provided in the gap between adjacent annular magnetic teeth.

2. The three-degree-of-freedom target disk-type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The permanent magnets are fixedly installed at the lower end of each pole piece in a one-to-one correspondence.

3. The three-degree-of-freedom target disk-type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The permanent magnet is fixed to the side of the pole shoe with opposite magnetic poles.

4. The three-degree-of-freedom target disk-type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The multi-pole shoe-type electromagnetic circuit assembly (12) is a U-shaped electromagnet, and the corresponding rotor magnetic disk (22) has two inner and outer annular magnetic teeth.

5. The three-degree-of-freedom target disk-type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The multi-pole shoe-type electromagnetic circuit assembly (12) is an E-type electromagnet, and the corresponding rotor magnetic disk (22) has three annular magnetic teeth: inner, middle, and outer.

6. The three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The mounting plate (1) is rectangular.

7. The three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: Each of the pole shoes is provided with a coil, and the multi-pole shoe electromagnetic circuit assembly (12) generates an attractive force on the rotor magnetic disk (22).

8. The three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The rotor assembly (2) has multiple rotor disks (22) with the same orientation fixed on its shaft (21), and each rotor disk (22) corresponds to a different stator assembly (1).

9. The three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: The rotor magnetic disk (22) is provided with the annular magnetic teeth on both sides. The annular magnetic teeth on both sides correspond to the stator assembly (1). The function of the stator assembly (1) located at the bottom is to balance the load size, obtain bidirectional thrust bearing capacity or improve the anti-overturning capacity.

10. The three-degree-of-freedom target disk type vertical hybrid magnetic levitation bearing structure as described in claim 1, characterized in that: Each pole shoe of the multi-pole shoe electromagnetic circuit assembly (12) has a concave side and a convex side, and the curvature of the concave side and the convex side corresponds to the curvature of the corresponding annular magnetic tooth.

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