Magnetic levitation device

Abstract

The present appliction discloses a magnetic levitation device. The magnetic levitation device comprises a magnetic levitation motor and an impeller. The magnetic levitation motor comprises a stator, a rotor, and a radial levitation assembly. The stator comprises a stator core and a drive coil. The stator core comprises a winding slot, and the drive coil is disposed in the winding slot. The rotor is sleeved inside the stator core, and is spaced apart from the stator core. The rotor comprises a permanent magnet, and the permanent magnet interacts with a magnetic field generated by the drive coil to generate a drive force acting on the rotor. The radial levitation assembly is used to suspend the rotor within the stator core. The impeller is fixedly connected to a rotor shaft, and when rotating, the impeller applies to the rotor an axial lift force in a first direction. One of the extension direction of the winding slot and a magnetic pole direction of the rotor is inclined relative to the first direction, so that the drive force has an axial component in the first direction. The axial component and the axial lift force are in opposite directions; therefore, after the two are combined, the force acting on the rotor in the first direction can be reduced, thereby enabling the rotor and the impeller to achieve stable axial levitation.

Description

A magnetic levitation device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411433836.0, filed on October 14, 2024, entitled "A Magnetic Levitation Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of mechanical equipment technology, and in particular to a magnetic levitation device. Background Technology

[0004] In magnetic levitation devices such as magnetic levitation pumps, the impeller is fixedly connected to the rotor of the magnetic levitation motor, and the rotor drives the impeller to rotate. The rotor of the magnetic levitation motor is suspended within its stator. Due to the lift force generated along the rotor axis during impeller rotation, the impeller and the rotor fixedly connected to it are prone to axial floating under the influence of this lift force. Axial floating of the impeller affects its fluid transport efficiency and increases the risk of collision with the internal structure of the magnetic levitation pump. Axial floating of the rotor affects the driving magnetic field between it and the stator, thus impacting the rotor's operational stability. Summary of the Invention

[0005] This application provides a magnetic levitation device to improve the operational stability of the magnetic levitation device.

[0006] In a first aspect, this application provides a magnetic levitation device, which includes a magnetic levitation motor and an impeller. The magnetic levitation motor includes a stator, a rotor, and a radial levitation assembly. The stator includes a stator core and a drive coil. The stator core includes a first end face and a second end face arranged opposite to each other along a first direction. The stator core has a winding slot extending from the first end face to the second end face. The drive coil is wound in the winding slot and can generate a driving magnetic field when energized. The rotor is sleeved inside the stator core, and the rotor and the stator core are spaced apart. The rotor includes a permanent magnet, and the magnetic field generated by the permanent magnet can interact with the driving magnetic field generated by the drive coil to generate a driving force acting on the rotor to drive the rotor to rotate around the first direction. The radial levitation assembly is used to levitate the rotor inside the stator core, so that the rotor and the stator remain in a non-contact state during operation. The impeller is fixedly connected to the rotor and can rotate under the drive of the rotor, applying an axial lift force along the first direction to the rotor during rotation. In this application, the extension direction of the winding slot is inclined relative to one of the magnetic pole directions of the rotor, so that the driving force acting on the rotor can be decomposed into an axial component along the first direction. This axial component is opposite to the axial lift generated by the rotation of the impeller. Therefore, the superposition of the two can reduce or even eliminate the force on the rotor in the first direction, so that the rotor and impeller can achieve stable axial suspension, thereby improving the operating stability of the magnetic levitation device.

[0007] In some implementations, under rated operating conditions, the axial component F of the driving force of the magnetic levitation device... 1a The axial lift F2 satisfies: |F 1a -F2| / F 1a ≤10%. Therefore, the axial component of the driving force can offset most of the axial lift generated by the impeller, thereby effectively improving the axial suspension stability of the rotor and impeller.

[0008] In some implementations, the winding slots extend parallel to the first direction, and the angle α between the rotor's magnetic pole direction and the first direction is 0° < α < 90°. Then, the axial component F of the driving force F1 is... 1a Let F1*sinα. It can be seen that when the extension direction of the winding slot is parallel to the first direction, the magnitude of the axial component of the driving force is related to the tilt angle of the rotor's magnetic pole direction relative to the first direction. In practical applications, the angle α can be designed according to the required magnitude of the axial component.

[0009] In some implementations, the magnetic poles of the rotor are arranged parallel to the first direction, and the angle between the extension direction of the winding slots and the first direction is β, where 0° < β < 90°. Then, the axial component of the driving force F1 is F... 1aF1*sinβ. It can be seen that when the magnetic pole direction of the rotor is parallel to the first direction, the magnitude of the axial component of the driving force is related to the tilt angle of the winding slot relative to the first direction. In practical applications, the size of the included angle β can be designed according to the required magnitude of the axial component.

[0010] In some implementations, the rotor includes a rotor core and a rotor shaft. The rotor core is fitted inside the stator core, and the rotor core and stator core are spaced apart. The rotor shaft is fitted inside the rotor core, and the rotor shaft and rotor core are relatively fixed. Permanent magnets are fixed to the rotor core. By rationally designing the fixing direction or arrangement direction of the permanent magnets in the rotor core, the magnetic pole direction of the rotor can be made parallel to or at a certain angle to a first direction.

[0011] For example, the permanent magnet can be made of high flux density permanent magnet materials such as neodymium iron boron permanent magnets, permanent magnet ferrites, and iron-chromium-cobalt permanent magnet alloys.

[0012] In some embodiments, the permanent magnet is fixed to the outer peripheral surface of the rotor core. For example, the permanent magnet can be surface-mounted to the outer peripheral surface of the rotor core, or it can be embedded in a slot formed on the outer peripheral surface of the rotor core. In other embodiments, the permanent magnet can also be embedded inside the rotor core.

[0013] In some embodiments, the permanent magnet can be a multi-pole magnetic ring. In this case, along the circumference of the rotor core, the N and S poles of the magnetic ring on the side facing away from the rotor shaft are alternately arranged so that the magnetic field generated by the magnetic ring can interact with the driving magnetic field generated by the drive coil to generate a driving force. In other embodiments, there can be multiple permanent magnets distributed along the circumference of the rotor core. The magnetic poles of two adjacent permanent magnets on the side facing away from the rotor shaft are opposite, so that the magnetic field generated by the multiple permanent magnets can interact with the driving magnetic field generated by the drive coil to generate a driving force.

[0014] In some embodiments, the stator core includes multiple stator laminations, which are annular in structure and are stacked sequentially along a first direction to form a cylindrical stator core. In other embodiments, the stator core includes multiple sub-cores, each sub-core including multiple arc-shaped stator laminations, and the multiple stator laminations of each sub-core are stacked sequentially along the first direction. Thus, the multiple sub-cores are sequentially spliced ​​together circumferentially to form a cylindrical stator core.

[0015] In some implementations, the radial suspension assembly is a magnetic levitation bearing, which includes an inner ring and an outer ring. The inner ring is fixed to the outer circumferential surface of the rotor shaft and is provided with a magnetic ring magnetized axially. The outer ring is sleeved on the outer circumferential side of the inner ring, with a gap between the two rings, and is provided with a suspension coil. The suspension coil can generate a suspension magnetic field when energized, causing the inner ring and the rotor fixedly connected to the inner ring to exist in a suspended state in the suspension magnetic field, thereby suspending the rotor in the stator.

[0016] In some implementations, the magnetic levitation device can be a magnetic levitation pump. The magnetic levitation pump also includes a housing with an inlet and an outlet. The magnetic levitation motor and impeller are disposed inside the housing. When the magnetic levitation motor operates, it drives the impeller to rotate. The impeller can pump fluid from the inlet to the outlet during rotation, enabling the magnetic levitation pump to deliver or pressurize fluid.

[0017] In some implementations, the magnetic levitation device can be a magnetic levitation fan. The magnetic levitation fan also includes a housing, with the magnetic levitation motor housed inside the housing and the impeller located outside. When the magnetic levitation motor operates, it drives the impeller to rotate, and the impeller, in turn, accelerates the circulation of surrounding air, enabling the magnetic levitation fan to perform its fanning function. Attached Figure Description

[0018] Figure 1 is a structural schematic diagram of a magnetic levitation device provided in an embodiment of this application;

[0019] Figure 2 is a partial exploded view of the magnetic levitation device shown in Figure 1;

[0020] Figure 3 is a schematic diagram of the structure of the magnetic levitation motor provided in the embodiment of this application;

[0021] Figure 4 is a schematic diagram of the permanent magnet provided in an embodiment of this application;

[0022] Figures 5a-5d are schematic diagrams of the force direction in a local part of the rotor;

[0023] Figure 6 is a schematic diagram of the stator core provided in an embodiment of this application;

[0024] Figures 7a-7d are schematic diagrams of the force direction in a local part of the stator;

[0025] Figure 8 is a graph showing the relationship between the axial component of the driving force and the tilt angle of the rotor's magnetic pole direction relative to the first direction.

[0026] Figure 9 shows the relationship between the axial lift of the impeller and its rotational speed, and the relationship between the torque of the impeller and its rotational speed under a certain working pressure.

[0027] Reference numerals: 1000 - Magnetic levitation device / magnetic levitation pump; 100 - Magnetic levitation motor; 110 - Stator; 111 - Stator core; 111a - First end face; 111b - Second end face; 1111 - Winding slot; 1112 - Sub-core; 112 - Drive coil; 120 - Rotor; 121 - Rotor core; 122 - Rotor shaft; 123 - Permanent magnet; 130 - Radial levitation assembly / magnetic levitation bearing; 131 - Inner ring; 132 - Outer ring; 200 - Impeller; 210 - Blade; 300 - Housing; 310 - Inlet; 320 - Outlet. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0029] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0030] Magnetic levitation motors utilize the principle of magnetic levitation to achieve contactless transmission and suspended operation. This operating method eliminates friction and wear inherent in traditional mechanical transmissions, thereby improving motor efficiency and lifespan. Furthermore, because the rotor of a magnetic levitation motor has no contact with the stator during rotation, frictional noise and vibration are reduced, resulting in low-noise operation. In addition, the relatively lightweight rotor of a magnetic levitation motor allows for faster acceleration and deceleration responses, facilitating precise motor control. Based on these advantages, magnetic levitation motors can be applied to various magnetic levitation devices, such as magnetic levitation pumps, centrifugal compressors, wind turbines, and magnetic levitation fans.

[0031] Figure 1 is a structural schematic diagram of a magnetic levitation device 1000 provided in an embodiment of this application, and Figure 2 is a partial exploded view of the magnetic levitation device 1000 shown in Figure 1. Figures 1 and 2 illustrate the magnetic levitation device 1000 as an example of a magnetic levitation pump; in the following embodiments, the magnetic levitation pump and the magnetic separation levitation device are referred to by the same reference numerals. The magnetic levitation pump 1000 can be applied in thermal management systems for various heat dissipation scenarios to drive the circulation of the heat exchange medium in the thermal management system. This allows the heat exchange medium to exchange heat through evaporation with high-temperature heat-dissipating devices or through condensation with low-temperature heat-dissipating devices during the flow process, thereby enabling the thermal management system to achieve heat dissipation or heating functions. Alternatively, the magnetic levitation pump 1000 can also be used as a medical device to help patients achieve blood circulation.

[0032] Figure 3 is a schematic diagram of the structure of the magnetic levitation motor provided in an embodiment of this application. Referring to Figures 2 and 3 together, the magnetic levitation pump 1000 includes a magnetic levitation motor 100 and an impeller 200. The magnetic levitation motor 100 includes a stator 110, a rotor 120, and a radial suspension assembly 130. The rotor 120 is rotatably mounted in the stator 110, and the radial suspension assembly 130 is used to apply a levitation force to the rotor 120, so that the rotor 120 remains in a non-contact state with the stator 110 during operation. The impeller 200 is fixedly connected to the rotor 120 so as to rotate synchronously with the rotor 120 under the drive of the rotor 120. The impeller 200 includes a plurality of blades 210 arranged circumferentially along the rotor 120. The blades 210 can generate a certain centrifugal force during rotation, thereby using the centrifugal force to drive the flow of fluid (such as heat exchange medium, blood, etc.).

[0033] In some embodiments, the magnetic levitation pump 1000 further includes a housing 300, in which the magnetic levitation motor 100 and the impeller 200 are housed. The housing 300 includes an inlet 310 and an outlet 320. During rotation, the impeller 200 can pump fluid from the inlet 310 to the outlet 320, enabling the magnetic levitation pump 1000 to deliver or pressurize fluid.

[0034] The rotor 120 includes a rotor core 121, a rotor shaft 122, and a permanent magnet 123. The rotor core 121 has a cylindrical structure, and the rotor shaft 122 is sleeved inside the rotor core 121. The rotor shaft 122 and the rotor core 121 are relatively fixed to each other, and at least one end of the rotor shaft 122 extends beyond the rotor core 121. Exemplarily, the rotor shaft 122 and the rotor core 121 can be fixedly connected by an interference fit. The permanent magnet 123 is fixed to the rotor core 121 and is radially magnetized. In one implementation, the permanent magnet 123 can be fixed to the outer peripheral surface of the rotor core 121. For example, the permanent magnet 123 can be surface-mounted to the outer peripheral surface of the rotor core 121, or a slot can be provided on the outer peripheral surface of the rotor core 121 to embed the permanent magnet 123 in the slot. In another implementation, the permanent magnet 123 can be embedded inside the rotor core 121. Figure 2 shows a case where a permanent magnet 123 is attached to the outer peripheral surface of the rotor core 121.

[0035] In some embodiments, the rotor core 121 includes a plurality of rotor laminations, which are stacked sequentially along a first direction Z. It is easy to understand that the first direction Z is the extension direction of the rotor core 121 and the rotor shaft 122, that is, the direction of the rotation axis of the rotor 120.

[0036] In some embodiments, the permanent magnet 123 may be made of high flux density permanent magnet materials such as neodymium iron boron permanent magnets, permanent magnet ferrite, and iron-chromium-cobalt permanent magnet alloys. Exemplarily, the permanent magnet 123 may be a single multi-pole magnetic ring, with the N and S poles alternately arranged on the side of the ring facing away from the rotor shaft along the circumference of the rotor core 121. Alternatively, there may be multiple permanent magnets 123, distributed along the circumference of the rotor core 121, with adjacent permanent magnets 123 having opposite magnetic poles on the side facing away from the rotor shaft 122.

[0037] The stator 110 includes a stator core 111 and a drive coil. The stator core 111 has a cylindrical structure and includes a first end face 111a and a second end face 111b arranged opposite each other along a first direction Z. The stator core 111 is provided with winding slots 1111. In a specific implementation, there are multiple winding slots 1111, which are circumferentially spaced on the inner circumference of the stator core 111, and each winding slot 1111 extends from the first end face 111a to the second end face 111b. The drive coil is wound in the multiple winding slots 1111. When energized, the drive coil can generate a driving magnetic field. The driving magnetic field can interact with the magnetic field generated by the permanent magnet 123 of the rotor 120 and generate a driving force acting on the rotor 120, thereby driving the rotor 120 to rotate relative to the stator 110.

[0038] In some embodiments, the stator core 111 includes a plurality of stator laminations, which are annular in structure and are stacked sequentially along a first direction Z. In other embodiments, the stator core 111 includes a plurality of sub-cores 1112, each sub-core 1112 including a plurality of arc-shaped stator laminations, and the plurality of stator laminations of each sub-core 1112 are stacked sequentially along the first direction Z. The plurality of sub-cores 1112 are then sequentially spliced ​​together circumferentially to form a cylindrical stator core 111.

[0039] The radial suspension assembly 130 is not limited in form. For example, in one embodiment, the radial suspension assembly 130 can be a magnetic levitation bearing. Hereinafter, the magnetic levitation bearing and the radial suspension assembly 130 are referred to by the same reference numerals. The magnetic levitation bearing 130 is sleeved on the rotor shaft 122. The magnetic levitation bearing 130 may include an inner ring 131 and an outer ring 132. The inner ring 131 is fixed to the outer peripheral surface of the rotor shaft 122 and is provided with an axially magnetized magnetic ring. The outer ring 132 is sleeved on the outer peripheral side of the inner ring 131, and there is a circumferential gap between the outer ring 132 and the inner ring 131. The outer ring 132 is provided with a suspension coil. The suspension coil can generate a suspension magnetic field when energized, causing the inner ring 131 and the rotor 120 fixedly connected to the inner ring 131 to exist in a suspended state in the suspension magnetic field, thereby allowing the rotor 120 to levitate within the stator 110.

[0040] In addition, in the magnetic levitation motor 100, the number of magnetic levitation bearings 130 can be at least one. For example, the magnetic levitation motor 100 includes two magnetic levitation bearings 130, which are respectively disposed at both ends of the rotor shaft 122 extending beyond the rotor core 121, so as to form levitation supports at both ends of the rotor shaft 122, thereby improving the reliability of the rotor 120 in levitation operation.

[0041] In other embodiments, the radial suspension assembly can also be a fluid-based suspension structure. The radial suspension assembly includes fluid filling the gap between the rotor and the stator core, with the rotor suspended within the stator core by the buoyancy of the fluid. In this case, cover plates can be respectively provided on the first and second end faces of the stator core to seal the gap between the rotor and the stator core, reducing the risk of fluid leakage.

[0042] Referring again to Figures 2 and 3, the impeller 200 is fixedly connected to the rotor 120. Specifically, the impeller 200 can be fixed to the rotor shaft 122. In one implementation, the impeller 200 is fixed to one end of the rotor shaft 122 extending beyond the rotor core 121, and the impeller 200 is positioned closer to the end of the rotor shaft 122 relative to the magnetic levitation bearing. This can also be understood as the impeller 200 being located on the side of the magnetic levitation bearing 130 facing away from the rotor core 121. During rotation, the impeller 200 generates axial lift (i.e., a force along the first direction Z). The magnitude and direction of this axial lift are related to factors such as the shape and arrangement of the blades 210 and the rotational speed of the impeller 200. Under the action of axial lift, the impeller 200 and the rotor 120 fixedly connected to the impeller 200 are prone to axial floating. The axial floating of the impeller 200 will affect its fluid conveying efficiency on the one hand, and will also increase the risk of it colliding with the internal structure of the magnetic levitation pump 1000 on the other hand. The axial floating of the rotor 120 will affect the driving magnetic field between it and the stator 110, which will in turn affect the operating stability of the rotor 120.

[0043] To address the aforementioned issues, embodiments of this application can improve the structure of the stator 110 or rotor 120, enabling the rotor 120 to generate a force resisting the axial lift generated by the rotation of the impeller 200 during rotation, thereby achieving stable axial levitation of the rotor 120 and the impeller 200. In a specific implementation, the winding slots 1111 of the stator core 111 and one of the magnetic poles of the rotor 120 are inclined relative to the first direction Z. In other words, the magnetic levitation motor 100 satisfies one of the following two conditions: 1) the extension direction of the drive coil within the winding slots 1111 is inclined relative to the first direction Z; 2) the magnetic poles of the rotor 120 are skewed poles.

[0044] It is easy to understand that the electromagnetic force experienced by the stator 110 in the magnetic field is equal in magnitude and opposite in direction to the driving force experienced by the rotor 120. For the drive coil, the electromagnetic force experienced by the drive coil is perpendicular to its extension direction within the winding slot 1111, that is, perpendicular to the extension direction of the winding slot 1111. Therefore, the driving force experienced by the rotor 120 is also perpendicular to the extension direction of the winding slot 1111. When the winding slot 1111 forms a certain angle with the first direction Z, the driving force experienced by the rotor 120 can be decomposed into a tangential component and an axial component. It is easy to understand that, given a fixed rotation direction of the rotor 120, by appropriately setting the inclination direction of the winding slot 1111 relative to the first direction Z, the desired tangential and axial components can be obtained. The tangential component is used to drive the rotor 120 to rotate, while the axial component can be used to balance the axial lift generated by the rotation of the impeller 200. In other words, the axial component force is opposite to the axial lift force generated by the rotation of the impeller 200. Therefore, the superposition of the two can reduce or even eliminate the force on the rotor 120 in the first direction Z, so that the rotor 120 and the impeller 200 can achieve stable axial suspension.

[0045] For rotor 120, the driving force acting on it is perpendicular to the magnetic pole direction line. When the magnetic poles of rotor 120 are skewed, the driving force can be decomposed into a tangential component and an axial component. Similarly, with the rotation direction of rotor 120 determined, by appropriately setting the inclination direction of the magnetic pole direction line, the desired tangential and axial components can be obtained. The tangential component drives rotor 120 to rotate, while the axial component balances the axial lift generated by the rotation of impeller 200, enabling rotor 120 and impeller 200 to achieve stable axial levitation.

[0046] In this embodiment of the application, the axial component of the driving force F1 is defined as F. 1a The axial lift generated by the rotation of the impeller 200 is F2. Under rated operating conditions, the magnetic levitation pump has F... 1a F2 satisfies: |F 1a -F2| / F 1a ≤10%. The rated operating conditions of the magnetic levitation pump 1000 can be determined by its design parameters. Under rated operating conditions, the pressure of the magnetic levitation pump 1000 is the maximum pressure required for normal operation, and correspondingly, the rotational speed of the rotor 120 of the magnetic levitation motor 100 is the maximum rotational speed required for normal operation. Through this design, the axial component force can offset most of the axial lift generated by the impeller, thus effectively improving the axial suspension stability of the rotor and impeller.

[0047] Figure 4 is a structural schematic diagram of the permanent magnet 123 provided in the embodiment of this application, and Figures 5a-5d are schematic diagrams of the force direction of a portion of the rotor 120. Referring also to Figures 2, 4, and 5a-5d, in the embodiment of this application, the extension direction of the winding slot 1111 is parallel to the first direction Z, and the angle between the magnetic pole direction of the rotor 120 and the first direction is α, where 0° < α < 90°. Therefore, the axial component F of the driving force F1 is... 1a Let F1*sinα be the tangential component of the driving force F1. 1t F1*cosα. The magnetic pole direction of the rotor 120 is achieved by the design of the permanent magnet 123. Taking the permanent magnet 123 in the form of a multi-pole magnetic ring in Figure 3 as an example, the permanent magnet 123 can be magnetized at an angle to make the magnetic field of the rotor 120 set at an angle.

[0048] Define the radius of rotor core 121 as R1, and the tangential component of driving force F1 as F 1t The generated torque T 1t =F 1t *R1. Axial component F of driving force F1 1a The tangential component F of the driving force F1 1t The generated torque T 1t satisfy:

[0049] Therefore, the axial component F of the driving force F1 1a The magnitude is also related to its tangential force F 1t The torque generated is related to the magnetic field strength. The greater the torque generated by rotor 120, the stronger the magnetic field, and the greater the driving force F1 on rotor 120. Therefore, the axial component of the driving force F1, F... 1a The torque T will also increase accordingly. It should be noted that the actual structure of rotor 120 is often quite complex, therefore the torque T... 1t The axial component of the driving force F1, F 1a This does not strictly conform to the above formula; it is only used here to illustrate the correlation between the two. In practical applications, the torque T can be obtained through finite element calculation using relevant simulation software. 1t The axial component of the driving force F1, F 1a The accurate relationship.

[0050] The axial component of the driving force F1 is related to the rotation direction of the rotor 120 and the tilt direction of its magnetic poles relative to the first direction Z. For example, in one example, referring to Figure 5a, from the positive Z-axis to the negative Z-axis, when the rotor rotates clockwise and the magnetic poles are tilted clockwise relative to the first direction Z, the axial component F of the driving force F1 is... 1aOriented towards the positive Z-axis; in one example, referring to Figure 5b, from the positive Z-axis to the negative Z-axis, when the rotor rotates counterclockwise and the magnetic pole direction is tilted clockwise relative to the first direction, the axial component F of the driving force F1 is... 1a Oriented towards the negative Z-axis; in one example, referring to Figure 5c, from the positive Z-axis to the negative Z-axis, when the rotor rotates clockwise and the magnetic pole direction is tilted counterclockwise relative to the first direction, the axial component F of the driving force F1 is... 1a Oriented towards the negative Z-axis; in one example, referring to Figure 5d, from the positive Z-axis to the negative Z-axis, when the rotor rotates counterclockwise and the magnetic pole direction is tilted counterclockwise relative to the first direction, the axial component F of the driving force F1 is... 1a Oriented towards the positive Z-axis; see Table 1 for details. In the design of a magnetic levitation pump, the axial component F of the driving force F1 can be selected according to the actual situation. 1a A scheme that is the opposite of the axial lift F2 of the impeller.

[0051] Table 1

[0052] Figure 6 is a structural schematic diagram of the stator core 111 provided in the embodiment of this application, and Figures 7a-7d are schematic diagrams of the force direction of a part of the stator 110. Referring also to Figures 2, 6, and 7a-7d, in the embodiment of this application, the magnetic pole direction of the rotor 120 is parallel to the first direction Z, and the angle between the extension direction of the winding slot 1111 and the first direction Z is β, where 0° < β < 90°. Then, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a 'F1'sinβ, the tangential component F of the electromagnetic force F1' acting on the driving coil 112 1t F1'cosβ. Since the driving force F1 on rotor 120 is equal in magnitude and opposite in direction to the electromagnetic force F1' on drive coil 112, the axial component F of driving force F1 is... 1a =F 1a =F1'sinβ=F1*sinβ, the tangential component of the driving force F1 is F 1t =F 1t =F1'cosβ = F1*cosβ.

[0053] Define the radius of the stator core 111 as R2, and the tangential component of the electromagnetic force F1' on the drive coil 112 as F 1t The generated torque T 1t '=F 1t *R2. The axial component F of the electromagnetic force F1' acting on the drive coil 112. 1a 'The torque T generated by the drive coil 112 1t 'satisfy:

[0054] Therefore, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a The magnitude of ' (i.e., the axial component F of the driving force F1) 1a The magnitude of the force (F) is also related to its tangential force. 1t The generated torque T 1t 'Related. The torque T generated by the drive coil 112 1t The larger the magnetic field strength, the greater the electromagnetic force F1 on the drive coil 112 (the driving force F1 on the rotor 120), and the greater the axial component F of the driving force F1. 1a The torque T also increases accordingly. It should be noted that, because the inner circumferential surface of the stator core 111 has multiple winding slots 1111, multiple tooth arms are formed between adjacent winding slots 1111 on the inner circumferential surface of the stator core 111. The shape of these tooth arms is often irregular, resulting in a relatively complex stress distribution. Therefore, the torque T... 1t 'Axial component F of electromagnetic force F1' 1a This does not strictly conform to the above formula; it is only used here to illustrate the correlation between the two. In practical applications, the torque T can be obtained through finite element calculation using relevant simulation software. 1t 'and axial component F 1a The exact relationship between ' and '.

[0055] Axial component F of driving force F1 1a The pointing direction is related to the rotation direction of the rotor 120 and the tilt direction of the winding slot 1111 relative to the first direction Z. For example, in one example, referring to FIG7a, from the positive direction of the Z-axis to the negative direction of the Z-axis, when the rotor rotates clockwise (the relative rotation direction of the stator is counterclockwise) and the winding slot 1111 is tilted clockwise relative to the first direction Z, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a 'If the driving force F1 is directed towards the negative Z-axis, then the axial component F...' 1a Oriented towards the positive Z-axis; in one example, referring to Figure 7b, from the positive Z-axis to the negative Z-axis, when the rotor rotates counterclockwise (the relative rotation direction of the stator is clockwise) and the winding slot 1111 is tilted clockwise relative to the first direction Z, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a 'If the direction is towards the positive Z-axis, then the axial component of the driving force F1 is F 1a Oriented towards the negative Z-axis; in one example, referring to Figure 7c, from the positive Z-axis to the negative Z-axis, when the rotor rotates clockwise (the stator rotates counterclockwise) and the winding slot 1111 is tilted counterclockwise relative to the first direction Z, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a'If the direction is towards the positive Z-axis, then the axial component of the driving force F1 is F 1a Oriented towards the negative Z-axis; in one example, referring to Figure 7d, from the positive Z-axis to the negative Z-axis, when the rotor rotates counterclockwise (the relative rotation direction of the stator is clockwise) and the winding slot 1111 is tilted counterclockwise relative to the first direction Z, the axial component F of the electromagnetic force F1' on the drive coil 112 is... 1a 'If the driving force F1 is directed towards the negative Z-axis, then the axial component F...' 1a Oriented towards the positive Z-axis; see Table 2 for details. In the design of a magnetic levitation pump, the axial component F of the driving force F1 can be selected according to the actual situation. 1a A scheme that is the opposite of the axial lift F2 of the impeller.

[0056] Table 2

[0057] Figure 8 shows the axial component F of the driving force F1. 1a The graph shows the relationship between the rotor's magnetic pole direction and the tilt angle α relative to the first direction. Combining Figure 8 with the preceding analysis, it can be seen that the larger the tilt angle α of the rotor's magnetic pole direction relative to the first direction, the larger the axial component F1 of the driving force F1. In practical applications, the tilt angle of the rotor's magnetic poles can be rationally designed based on the operating parameters of the magnetic levitation pump and the impeller's structural form.

[0058] In addition, the axial component F of the driving force F1 1a The tilt angle β of the winding slot relative to the first direction is also positively correlated. The relationship curve between the two is roughly the same as that shown in Figure 8, and will not be elaborated further here.

[0059] Figure 9 shows the relationship between the impeller's axial lift F2 and rotational speed n, and the impeller's torque T0 and rotational speed n under a certain operating pressure. The horizontal axis represents the impeller's rotational speed n, and the vertical axis represents the ratio of the impeller's axial lift F2 to its torque T0. The solid line represents the relationship between the impeller's axial lift F2 and rotational speed n, and the dashed line represents the relationship between the impeller's torque T0 and rotational speed n. Since the impeller and rotor rotate synchronously and can be considered as a single unit, the impeller's rotational speed n is the same as the rotor's rotational speed, and the impeller's torque T0 can also characterize the rotor's torque. As can be seen from Figure 9, under a constant operating pressure, the impeller's axial lift F2 and rotational speed, and the impeller's torque T0 and rotational speed, are positively correlated. When the impeller's rotational speed n increases, both the impeller's axial lift F2 and torque increase, and correspondingly, the rotor's torque T0 also increases synchronously. Conversely, when the impeller's rotational speed n decreases, both the impeller's axial lift F2 and torque decrease, and correspondingly, the rotor's torque T0 also decreases synchronously. As mentioned above, the greater the rotor torque, the stronger the magnetic field, and the greater the driving force F1 on the rotor. Therefore, the axial component of the driving force F1, F... 1aThe larger the magnetic field strength, the smaller the rotor torque, the weaker the magnetic field strength, and the smaller the driving force F1 on the rotor. The axial component of the driving force F1, F... 1a The smaller it is.

[0060] Based on the above analysis, it can be concluded that when the axial lift force F2 of the impeller increases, the axial component of the driving force F1, F... 1a It will also increase, while when the axial lift F2 of the impeller decreases, the axial component of the driving force F1, F 1a It will also decrease. That is to say, the axial component F of the driving force F1 will decrease. 1a It can automatically change with the axial lift F2 of the impeller, and the two are positively correlated. Thus, under any operating condition within its operating range, the axial component F of the driving force F1 will change. 1a Both methods effectively balance the axial lift force F2 of the impeller, ensuring stable axial levitation of the rotor and impeller throughout the entire operating range of the magnetic levitation pump. Compared to existing technologies that use axial magnetic levitation bearings or special structures to maintain axial levitation of the rotor and impeller, this embodiment offers relatively simple and cost-effective structural improvements to the stator or rotor. Furthermore, since no additional components are required, the magnetic levitation pump has a simpler structure, making it easier to miniaturize.

[0061] This application also provides another magnetic levitation device, which can be a magnetic levitation fan. The magnetic levitation fan includes a housing, a magnetic levitation motor, and an impeller. The magnetic levitation motor is housed inside the housing, and the impeller is located outside the housing. The structure and connection method of the magnetic levitation motor and impeller can be designed with reference to the aforementioned embodiments, and will not be repeated here. When the magnetic levitation motor operates, it drives the impeller to rotate. During rotation, the impeller accelerates the flow of surrounding air, enabling the magnetic levitation fan to perform its fan function. By improving the structure of the stator or rotor of the magnetic levitation motor, the rotor can generate a force that resists the axial lift generated by the impeller rotation during rotation, thereby enabling the rotor and impeller to be stably levitated axially, improving the reliability of the magnetic levitation fan.

[0062] This is merely a specific embodiment of the present application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A magnetic levitation device, characterized in that, The system includes a magnetic levitation motor and an impeller. The magnetic levitation motor comprises a stator, a rotor, and a radial suspension assembly, wherein: The stator includes a stator core and a drive coil; the stator core includes a first end face, a second end face, and a winding slot, the first end face and the second end face being arranged opposite to each other along a first direction; the winding slot extends from the first end face to the second end face; the drive coil is disposed in the winding slot; The rotor is sleeved inside the stator core, and the rotor and the stator core are spaced apart; the rotor includes a permanent magnet, and the magnetic field generated by the permanent magnet interacts with the magnetic field generated by the drive coil to generate a driving force acting on the rotor; The radial suspension assembly is used to suspend the rotor within the stator core; The impeller is fixedly connected to the rotor. The impeller rotates under the drive of the rotor and applies an axial lift force to the rotor along the first direction. The extension direction of the winding slot is inclined relative to one of the magnetic pole directions of the rotor relative to the first direction, and the driving force has an axial component along the first direction, which is opposite to the direction of the axial lift. The first direction is the direction of the rotation axis of the rotor.

2. The magnetic levitation device as described in claim 1, characterized in that, Under rated operating conditions, the axial component force F of the magnetic levitation device 1a The axial lift force F2 satisfies: |F 1a -F2| / F 1a ≤10%.

3. The magnetic levitation device as described in claim 1 or 2, characterized in that, The winding slot extends in a direction parallel to the first direction, and the angle between the magnetic pole direction of the rotor and the first direction is α, where 0° < α < 90°. The axial component F 1a =F1*sinα, where F1 is the driving force.

4. The magnetic levitation device as described in claim 1 or 2, characterized in that, The magnetic pole direction of the rotor is parallel to the first direction, and the angle between the extension direction of the winding slot and the first direction is β, where 0° < β < 90°. The axial component F 1a =F1*sinβ, where F1 is the driving force.

5. The magnetic levitation device according to any one of claims 1-4, characterized in that, The rotor also includes a rotor core and a rotor shaft. The rotor core is sleeved inside the stator core, and the rotor core and the stator core are spaced apart. The rotor shaft is sleeved inside the rotor core, and the rotor shaft and the rotor core are fixed relative to each other. The permanent magnet is fixed to the rotor core.

6. The magnetic levitation device as described in claim 5, characterized in that, The permanent magnet is fixed to the outer peripheral surface of the rotor core; or, the permanent magnet is embedded inside the rotor core.

7. The magnetic levitation device as described in claim 5 or 6, characterized in that, The permanent magnet is a multi-pole magnetic ring; or, there are multiple permanent magnets distributed circumferentially along the rotor core.

8. The magnetic levitation device according to any one of claims 1-7, characterized in that, The stator core includes a plurality of stator laminations stacked along the first direction, the stator laminations being annular structures; or, the stator core includes a plurality of sub-cores, the plurality of sub-cores being spliced ​​together along the circumference of the stator core, each sub-core including a plurality of stator laminations stacked along the first direction.

9. The magnetic levitation device according to any one of claims 1-8, characterized in that, The magnetic levitation device is a magnetic levitation pump, and the magnetic levitation pump also includes a housing, which includes an inlet and an outlet. The magnetic levitation motor and the impeller are disposed inside the housing, and the impeller is used to pump fluid from the inlet to the outlet during rotation.

10. The magnetic levitation device according to any one of claims 1-8, characterized in that, The magnetic levitation device is a magnetic levitation fan, which also includes a housing, a magnetic levitation motor located inside the housing, and an impeller located outside the housing.

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