Magnetic levitation electric motor and pump

Abstract

The present invention relates to a magnetic levitation electric motor and a pump. The magnetic levitation electric motor comprises: permanent magnet rotors, a main shaft and stator assemblies, wherein the two permanent magnet rotors are coaxial and are arranged axially, the two permanent magnet rotors are each fixedly connected to the main shaft, and the two permanent magnet rotors have the same number of magnetic poles; and the two stator assemblies are respectively located outside the two permanent magnet rotors, and the two stator assemblies respectively drive the two permanent magnet rotors to levitate and rotate by means of magnetic forces. In the present invention, each of the two stator assemblies corresponds to one permanent magnet rotor to form one or two independent magnetic circuits, which improves the total electromagnetic force on the permanent magnet rotor, thereby providing higher power for the main shaft under the condition of the same size of the electric motor, and thus increasing the flow rate and head of the pump.

Description

A magnetic levitation motor and pump Technical Field

[0001] This invention relates to the field of magnetic levitation bearingless motor technology, and in particular to a magnetic levitation motor and pump. Background Technology

[0002] Traditional centrifugal pumps typically use mechanical bearings to support and position the rotor. This design is susceptible to problems such as bearing wear, lubricant failure, unreliable seals, and inability to meet ultra-cleanliness requirements. Furthermore, traditional pumps suffer from vibration and noise issues, and have high operating costs. To overcome these drawbacks, magnetic levitation technology has been widely applied in the pump industry.

[0003] Magnetic levitation technology uses a magnetic field to levitate the impeller within the pump casing, achieving contactless and wear-free operation. Compared to traditional mechanical bearing centrifugal pumps, magnetic levitation pumps offer higher efficiency, longer lifespan, and lower maintenance costs.

[0004] Despite significant progress in magnetic levitation pumps, some challenges remain with the existing technology. In particular, the thin-plate magnetic levitation motor, which drives the magnetic levitation pump, faces bottlenecks for high-flow-rate pumps, such as low torque and poor stability during rotation.

[0005] The end of the main shaft of the magnetic levitation motor is fixedly connected to the impeller, which exerts a radial force on the main shaft. When the radial force on the main shaft is small, the magnetic resistance between the permanent magnet rotor and the stator can suppress the main shaft deflection; however, when the radial force on the main shaft is large, the stator needs to exert additional magnetic force on the permanent magnet rotor to suppress the deflection of the main shaft. Currently, the magnetic levitation motors used in magnetic levitation pumps only have one permanent magnet rotor installed inside the main shaft, resulting in a large deflection amplitude of the main shaft. Summary of the Invention

[0006] The present invention aims to solve the above problems by providing a magnetic levitation motor and pump, which solves the above technical problems.

[0007] A magnetic levitation motor includes: a permanent magnet rotor, a main shaft, and a stator assembly. The two permanent magnet rotors are coaxial and arranged along the axial direction. The two permanent magnet rotors are fixedly connected to the main shaft respectively. The two permanent magnet rotors have the same number of magnetic poles. The two stator assemblies are located outside the two permanent magnet rotors respectively. The two stator assemblies drive the two permanent magnet rotors to levitate and rotate through magnetic force.

[0008] Furthermore, the stator assembly includes a first magnetic yoke and a coil group, the coil group being fitted onto the outside of the first magnetic yoke, and the first magnetic yoke and the coil group being evenly arranged in a circle around the permanent magnet rotor.

[0009] Furthermore, the coil assembly includes a levitation coil and a rotating coil, which are respectively mounted on the outside of the first magnetic yoke. The rotating coil is used to drive the permanent magnet rotor to rotate, and the levitation coil and the rotating coil together drive the permanent magnet rotor to levitate.

[0010] Optionally, the magnetic poles of the two permanent magnet rotors are arranged in opposite directions.

[0011] Furthermore, the two stator assemblies share a common first magnetic yoke and coil assembly. The first magnetic yoke includes an axial arm and a radial arm. The two ends of the axial arm are respectively fixedly connected to the inwardly protruding radial arm. The two radial arms of the same first magnetic yoke are located on the outside of the two permanent magnet rotors, and the coil assembly is fitted on the outside of the axial arm.

[0012] Optionally, the magnetic poles of the two permanent magnet rotors are arranged in the same direction.

[0013] Furthermore, it also includes a second magnetic yoke. The two stator assemblies share a first magnetic yoke. The first magnetic yoke includes an axial arm and a radial arm. The two ends of the axial arm are respectively fixedly connected to the inwardly protruding radial arm. The two radial arms of the same first magnetic yoke are respectively located outside the two permanent magnet rotors. The axial arm passes through the second magnetic yoke. The coil groups of the two stator assemblies are respectively fitted on the outside of the axial arm and are respectively located on both sides of the axial direction of the second magnetic yoke.

[0014] Furthermore, the second magnetic yoke is annular, and the main shaft passes through a through hole inside the second magnetic yoke. The main shaft is made of a non-magnetic material. The first magnetic yoke is in contact with and fixedly connected to the second magnetic yoke.

[0015] Furthermore, it also includes a housing, wherein the stator assembly is located inside the housing and fixedly connected to the housing, and the permanent magnet rotor and the main shaft do not contact the housing.

[0016] A pump using the aforementioned magnetic levitation motor further includes a pump casing and an impeller. The pump casing is fixed to a housing and has an inlet and an outlet. The permanent magnet rotor and the main shaft are located inside the pump casing, and the impeller is fixedly connected to the permanent magnet rotor and / or the main shaft.

[0017] The present invention has the following advantages:

[0018] 1. The two stator assemblies each correspond to a permanent magnet rotor, forming one or two independent magnetic circuits, which increases the total electromagnetic force on the permanent magnet rotor. Thus, with the same motor size, it provides greater power to the main shaft, thereby increasing the pump's flow rate and head.

[0019] 2. Two independent magnetic circuits can change the magnetic force on the two permanent magnet rotors respectively, so that when the main shaft is subjected to radial external force at the end near the impeller, two forces of different magnitudes are applied to the two ends of the main shaft, reducing the offset and deflection amplitude of the main shaft and improving the stability of the main shaft during rotation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0021] Figure 1: Schematic cross-sectional view of the magnetic levitation motor in Embodiment 1;

[0022] Figure 2: Schematic diagram of the magnetic pole changes of the rotating magnetic field in Example 1;

[0023] Figure 3: Schematic diagram of the magnetic pole changes of the levitation magnetic field in Example 1;

[0024] Figure 4: Schematic diagram of the three-dimensional structure of the magnetic levitation motor after removing the housing in Example 1;

[0025] Figure 5: Schematic diagram of cross-sectional structure of magnetic levitation pump (one of the following).

[0026] Figure 6: Schematic diagram of the cross-sectional structure at point AA in Figure 5;

[0027] Figure 7: Schematic diagram of the three-dimensional structure of the magnetic levitation pump;

[0028] Figure 8: Schematic cross-sectional view of the magnetic levitation motor in Embodiment 2;

[0029] Figure 9: Schematic diagram of the magnetic pole changes of the rotating magnetic field in Example 2;

[0030] Figure 10: Schematic diagram of the magnetic pole changes of the levitation magnetic field in Example 2;

[0031] Figure 11: Schematic diagram of the three-dimensional structure of the magnetic levitation motor after removing the housing in Embodiment 2;

[0032] Figure 12: Schematic diagram of the three-dimensional structure of the magnetic levitation motor after removing the housing and main shaft in Embodiment 2;

[0033] Figure 13: Second cross-sectional view of the magnetic levitation pump;

[0034] Figure 14: Schematic diagram of the cross-sectional structure at BB in Figure 13. Embodiments of the present invention

[0035] The present invention will be further described below with reference to the accompanying drawings and examples:

[0036] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Example 1:

[0040] As shown in Figures 1 to 7, a magnetic levitation motor includes: a permanent magnet rotor 4, a main shaft 5, and a stator assembly. The two permanent magnet rotors 4 are coaxial and arranged along the axial direction. The two permanent magnet rotors 4 are fixedly connected to the main shaft 5 respectively. The two permanent magnet rotors 4 have the same number of magnetic poles. The two stator assemblies are located outside the two permanent magnet rotors 4 respectively. The two stator assemblies drive the two permanent magnet rotors 4 to levitate and rotate through magnetic force.

[0041] Furthermore, the stator assembly includes a first magnetic yoke 1 and a coil group, the coil group being fitted outside the first magnetic yoke 1, and the first magnetic yoke 1 and the coil group being evenly arranged in a circle around the permanent magnet rotor 4.

[0042] Each coil group may include one or more coils:

[0043] Alternatively, a coil group may consist of a single coil. In this case, a single coil provides both the rotating magnetic field and the levitation magnetic field to the permanent magnet rotor 4. While the structure using only a single coil is simpler, it places higher demands on the control system.

[0044] Optionally, the coil group includes a levitation coil 2 and a rotating coil 3, which are respectively mounted on the outside of the first magnetic yoke 1. The rotating coil 3 is used to drive the permanent magnet rotor 4 to rotate, and the levitation coil 2 and the rotating coil 3 together drive the permanent magnet rotor 4 to levitate.

[0045] Furthermore, the magnetic poles of the two permanent magnet rotors 4 are arranged in opposite directions.

[0046] Stator assemblies can share components or consist of two independent stator assemblies with separate components:

[0047] Optionally, the two stator assemblies share a common first magnetic yoke 1 and coil assembly. The first magnetic yoke 1 includes an axial arm 11 and a radial arm 12. The two ends of the axial arm 11 are respectively fixedly connected to the inwardly protruding radial arm 12. The two radial arms 12 of the same first magnetic yoke 1 are located on the outside of the two permanent magnet rotors 4, and the coil assembly is fitted on the outside of the axial arm 11. The inward protrusion of the radial arm 12 can reduce the air gap between the radial arm 12 and the permanent magnet rotor 4, thereby reducing magnetic leakage.

[0048] Optionally, each of the two stator assemblies includes a first magnetic yoke 1 and a coil assembly. The ends of the first magnetic yokes 1 of the two stator assemblies are in contact with each other, allowing the magnetic circuit to pass through the first magnetic yokes 1 of the two stator assemblies. The coil assemblies of the two stator assemblies are respectively fitted onto the outside of the first magnetic yokes 1 of each stator assembly.

[0049] Furthermore, it also includes a housing 6, the stator assembly is located inside the housing 6 and fixedly connected to the housing 6, and the permanent magnet rotor 4 and the main shaft 5 do not contact the housing 6.

[0050] Furthermore, the main shaft 5 is made of a non-magnetic material, thereby avoiding the formation of an axial magnetic circuit between the two permanent magnet rotors 4 in the main shaft 5.

[0051] Furthermore, adjacent first yokes 1 in the same stator assembly are not connected by a magnetically conductive material. Adjacent first yokes 1 refer to two circumferentially adjacent first yokes 1. This is because the two stator assemblies together form a magnetic circuit, and if two circumferentially adjacent first yokes 1 were connected by a magnetically conductive material, the magnetic circuit would be altered.

[0052] Furthermore, each permanent magnet rotor 4 has 1 pole pair.

[0053] Furthermore, the upper and lower permanent magnet rotors 4 are identical, and the upper and lower stator assemblies are identical.

[0054] As shown in Figures 1 to 4, the levitation rotation principle of this embodiment is illustrated by taking an example where each stator assembly has 8 first magnetic yokes 1 and 8 coil groups, and two stator assemblies share the same first magnetic yokes 1 and coil groups, and each permanent magnet rotor 4 has 2 magnetic poles. It should be noted that this embodiment can actually accommodate motors with various numbers of permanent magnet rotors 4 with different numbers of magnetic poles and different numbers of coil groups.

[0055] For rotation, similar to permanent magnet synchronous motors, the stator typically needs to generate a rotating magnetic field with the same number of poles as the permanent magnet rotor 4. Since this embodiment consists of two axially arranged permanent magnet rotors 4, and the coaxial permanent magnet rotors 4 are not connected by a magnetic material, and the first magnetic yoke 1 is C-shaped and adjacent first magnetic yokes 1 are not connected by a magnetic material, in order to realize the rotating magnetic field, the magnetic pole positions of the double-layer permanent magnet rotor 4 need to be misaligned. That is, when the permanent magnet rotor 4 has 1 pole pair, the same magnetic poles of the double-layer permanent magnet rotor 4 are offset by 180°.

[0056] It should be noted that when the permanent magnet rotor 4 has M pole pairs, the same poles of the permanent magnet rotor 4 are offset by 180° / M.

[0057] Now, let the rotating coils 3 of two adjacent first magnetic yokes 1 be filled with current in the same direction, and generate N-pole magnetic field at a certain moment. Then, the rotating coils 3 of the two radially symmetrical first magnetic yokes 1 should be filled with current in opposite directions, so that S-pole magnetic field is generated at the same moment. At this time, a pair of magnetic fields required for rotation are formed. Through the phase change of the current, the pair of magnetic fields are rotated, thereby driving the permanent magnet rotor 4 to rotate. The position change of the rotating magnetic field and the permanent magnet rotor 4 is shown in Figure 2.

[0058] In Figure 2, both the upper and lower layers are viewed from above. The "upper layer" in Figure 2 refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 4, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 4, the angle below refers to the rotation angle of the permanent magnet rotor 4, the magnetic field inside the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the rotating magnetic field of the corresponding radial arm 12.

[0059] The rotating magnetic field circuit within the radially symmetrical first magnetic yoke 1 is shown in Figure 1, with the two stator assemblies forming a single magnetic circuit. Radial active levitation of the permanent magnet rotor 4 requires the generation of a two-pole magnetic field through energizing the levitation coil 2 of the stator, a technology already in place in the field of magnetic levitation motors. The number of levitation pole pairs equals the number of rotating pole pairs ± 1 pair. Offset correction of the permanent magnet rotor 4 is achieved by superimposing the levitation magnetic field onto the rotating magnetic field, resulting in a combined magnetic field.

[0060] The change of the levitation magnetic field of the double-layer permanent magnet rotor 4 can be understood through Figure 3. Except for the radial 2 degrees of freedom which are active levitation and axial rotation, the other degrees of freedom are passive levitation. Since the double-layer permanent magnet rotor 4 needs to participate simultaneously to form the main magnetic circuit 13 when a certain stator needs to work, the magnitude of the corrective force on the two permanent magnet rotors 4 will be the same regardless of whether they are actively or passively levitation.

[0061] In Figure 3, both the upper and lower layers are viewed from above. The "upper layer" in Figure 3 refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 4, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 4, the angle below refers to the rotation angle of the permanent magnet rotor 4, the magnetic field inside the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the levitation magnetic field of the corresponding stator assembly.

[0062] Since the two permanent magnet rotors 4 are placed coaxially at both ends of the main shaft, compared with the existing magnetic levitation thin-film motor with only one permanent magnet rotor 4, this structure can better levitate and rotate a relatively long shaft and output greater power.

[0063] Example 2:

[0064] As shown in Figures 7 to 14, a magnetic levitation motor includes: a permanent magnet rotor 4, a main shaft 5, and a stator assembly. The two permanent magnet rotors 4 are coaxial and arranged along the axial direction. The two permanent magnet rotors 4 are fixedly connected to the main shaft 5 respectively. The two permanent magnet rotors 4 have the same number of magnetic poles. The two stator assemblies are located outside the two permanent magnet rotors 4 respectively. The two stator assemblies drive the two permanent magnet rotors 4 to levitate and rotate through magnetic force.

[0065] Furthermore, the stator assembly includes a first magnetic yoke 1 and a coil group, the coil group being fitted outside the first magnetic yoke 1, and the first magnetic yoke 1 and the coil group being evenly arranged in a circle around the permanent magnet rotor 4.

[0066] Each coil group may include one or more coils:

[0067] Optionally, a coil group includes a single coil. In this case, a single coil provides both the rotating magnetic field and the levitation magnetic field to a permanent magnet rotor 4. The structure using only a single coil is simpler, but it places higher demands on the control system.

[0068] Optionally, the coil group includes a levitation coil 2 and a rotating coil 3, which are respectively mounted on the outside of the first magnetic yoke 1. The rotating coil 3 is used to drive the permanent magnet rotor 4 to rotate, and the levitation coil 2 and the rotating coil 3 together drive the permanent magnet rotor 4 to levitate. This method uses more coils per coil group, but requires less control from the control system.

[0069] Furthermore, the magnetic poles of the two permanent magnet rotors 4 are arranged in the same direction. Each permanent magnet rotor 4 can cooperate with its corresponding stator assembly to form its own independent closed magnetic circuit, and each independent magnetic circuit is used for the levitation and rotation of the corresponding permanent magnet rotor 4. The magnetic poles being arranged in the same direction means that a straight line parallel to the axis of the permanent magnet rotor 4 passes through any two magnetic poles of the two permanent magnet rotors 4, and the polarity of the two magnetic poles is the same.

[0070] Furthermore, it also includes a second magnetic yoke 8. The two stator assemblies share a first magnetic yoke 1. The first magnetic yoke 1 includes an axial arm 11 and a radial arm 12. The two ends of the axial arm 11 are fixedly connected to the inwardly protruding radial arm 12. The two radial arms 12 of the same first magnetic yoke 1 are located on the outside of the two permanent magnet rotors 4, respectively. The axial arm 11 passes through the second magnetic yoke 8. The coil groups of the two stator assemblies are respectively fitted on the outside of the axial arm 11 and are located on both axial sides of the second magnetic yoke 8. The second magnetic yoke 8 serves as a magnetic conductor. The two independent magnetic circuits share one second magnetic yoke 8, and both independent magnetic circuits pass through the second magnetic yoke 8.

[0071] The radial arm 12 protrudes inward, which can make the distance between the radial arm 12 and the permanent magnet rotor 4 closer and the air gap smaller, thereby reducing magnetic leakage.

[0072] Furthermore, the second magnetic yoke 8 is annular, and the main shaft 5 passes through the through hole inside the second magnetic yoke 8. The main shaft 5 is made of non-magnetic material, thereby avoiding the formation of an axial magnetic circuit between the two permanent magnet rotors 4 in the main shaft 5; the first magnetic yoke 1 contacts and is fixedly connected to the second magnetic yoke 8.

[0073] Furthermore, it also includes a radial sensor and a controller. The radial sensor is used to detect the radial position of the upper and lower ends of the main shaft 5, and the controller is used to change the current of the suspension coil 2 in the coil group. By changing the magnitude of the current in the upper and lower suspension coils 2, different magnetic forces are applied to the two permanent magnet rotors 4, causing the main shaft 5 to deflect.

[0074] Furthermore, it also includes a housing 6, the stator assembly is located inside the housing 6 and fixedly connected to the housing 6, and the permanent magnet rotor 4 and the main shaft 5 do not contact the housing 6.

[0075] Furthermore, each permanent magnet rotor 4 has 1 pole pair.

[0076] This embodiment uses an example where each stator assembly has 8 coil groups and each permanent magnet rotor 4 has two radially magnetized magnetic poles to explain the levitation and rotation principle of two permanent magnet rotors 4 corresponding to an independent magnetic circuit. It should be noted that the structure of the two permanent magnet rotors 4 corresponding to one magnetic circuit in this embodiment is not only applicable to the aforementioned eight first magnetic yokes 1 and two magnetic poles of the permanent magnet rotor 4, but also applicable to various combinations of permanent magnet rotors 4 with different numbers of magnetic poles and different numbers of coil groups.

[0077] As shown in Figure 8, the upper coil group generates magnetomotive force, and the upper magnetic circuit passes through the upper half of the left first magnetic yoke 1, the upper permanent magnet rotor 4, the upper half of the right first magnetic yoke 1 and the second magnetic yoke 8 respectively; the lower coil group generates magnetomotive force, and the lower magnetic circuit passes through the lower half of the left first magnetic yoke 1, the lower permanent magnet rotor 4, the lower half of the right first magnetic yoke 1 and the second magnetic yoke 8 respectively.

[0078] It should be noted that each independent main magnetic circuit 13 (with arrows in Figure 8) includes two components: the rotating magnetic circuit generated by the rotating coil 3 and the levitation magnetic circuit generated by the levitation coil 2.

[0079] Now, let the rotating coils 3 of two adjacent first magnetic yokes 1 be energized with current in the same direction. At a certain moment, an N-pole magnetic field is generated. Then, the rotating coils 3 of the two radially symmetrical first magnetic yokes 1 (on the same stator assembly) should be energized with current in opposite directions, so that an S-pole magnetic field is generated at the same moment. At this time, a pair of magnetic fields required for rotation are formed. Through the phase change of the current, the pair of magnetic fields are rotated, thereby driving the permanent magnet rotor 4 to rotate. The position change of the rotating magnetic field and the permanent magnet rotor 4 is shown in Figure 9.

[0080] In Figure 9, both the upper and lower layers are viewed from above. The "upper layer" in Figure 9 refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 4, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 4, the angle below refers to the rotation angle of the permanent magnet rotor 4, the magnetic field inside the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the rotating magnetic field of the corresponding radial arm 12.

[0081] Radial active levitation of the permanent magnet rotor 4 requires the generation of two pairs of magnetic poles by energizing the levitation coil 2 of the stator assembly, which is existing technology in the field of magnetic levitation motors. The number of levitation magnetic pole pairs is equal to the number of rotating magnetic pole pairs ± 1 pair. The offset correction of the permanent magnet rotor 4 is achieved by superimposing the levitation magnetic field onto the resultant magnetic field of the rotating magnetic field.

[0082] The positional changes of the levitation magnetic field and the permanent magnet rotor 4 are shown in Figure 10. In Figure 10, both the upper and lower layers are viewed from above. The "upper layer" in Figure 10 refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 4, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 4, the angle below refers to the rotation angle of the permanent magnet rotor 4, the magnetic field inside the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the levitation magnetic field of the corresponding stator assembly.

[0083] Of these, apart from the radial 2 degrees of freedom which are active suspension and axial rotation, the remaining degrees of freedom are all passive suspension.

[0084] It should be noted that since the polarities of the magnetic poles along the axes of the two permanent magnet rotors 4 are the same, the polarities of the two radial arms 12 of the same first magnetic yoke 1 are also the same.

[0085] In this embodiment, since the upper and lower layers can form separate closed loops, the thickness and magnitude of the permanent magnet rotors 4 in the upper and lower layers of Figure 8 can be different. Different magnitudes of permanent magnet force will result in different levitation forces on the two permanent magnet rotors 4. To address the potentially different force requirements at both ends of the main shaft 5 in actual situations, the thicknesses of the two permanent magnet rotors 4 can be set to be different. Simultaneously, the thickness of the corresponding radial arm 12 should also be adjusted dynamically according to the change in the thickness of the permanent magnet rotors 4, thereby reducing unnecessary magnetic leakage caused by the inconsistency in thickness between the permanent magnet rotors 4 and the radial arm 12.

[0086] During operation, the rotation of the main shaft 5 drives the load to rotate, and the suspension of the main shaft 5 reduces friction. The two stator assemblies, together with the two permanent magnet rotors 4, increase the output power of the main shaft 5 without changing the volume.

[0087] Example 3:

[0088] As shown in Figures 1 to 14, a pump using a magnetic levitation motor of Embodiment 1 or Embodiment 2 further includes a pump casing 7 and an impeller 73. The pump casing 7 is fixed to the housing 6. The pump casing 7 has an inlet 71 and an outlet 72. The permanent magnet rotor 4 and the main shaft 5 are located inside the pump casing 7. The impeller 73 is fixedly connected to the permanent magnet rotor 4 and / or the main shaft 5.

[0089] Furthermore, the pump housing 7 includes an end cover 74, a pump body 75, and a cylinder 76. The pump body 75 is fixed to and detachably connected to the housing 6. The end of the pump body 75 away from the housing 6 is fixed to and detachably connected to the end cover 74. The end of the pump body 75 near the housing 6 is fixedly connected to the cylinder 76. A central channel 60 is formed inside the housing 6. The cylinder 76 is inserted into the central channel 60. The permanent magnet rotor 4 and the main shaft 5 are located inside the cylinder 76.

[0090] During operation, the main shaft 5 and impeller 73 rotate synchronously, drawing fluid in through inlet 71 and pumping it out through outlet 72. The permanent magnet force of the permanent magnet rotor 4 is greater than that of existing magnetic levitation sheet motors with a single permanent magnet shaft of the same diameter and a thickness equal to the sum of the thicknesses of two permanent magnet rotors 4. Therefore, this embodiment outputs higher power and torque, better meeting the demands of large flow rates or high head. Compared to existing magnetic levitation sheet motors, this embodiment does not increase thickness (i.e., axial length), thus providing higher flow rate and head within the same volume.

[0091] Since the main shaft 5 is subjected to a radial fluid force at the end near the impeller 73, the distances from the two permanent magnet rotors 4 to the point where the main shaft 5 is subjected to the radial fluid force are different. When the radial force on the main shaft 5 is small, the magnetic resistance between the permanent magnet rotor 4 and the stator assembly can suppress the offset of the main shaft 5.

[0092] However, when the radial external force on the main shaft 5 is too large, external forces need to be applied at both the upper and lower ends to suppress it. Since the lower permanent magnet rotor 4 is far from the force point of the main shaft 5, the lever arm is longer, so the deflection of the main shaft 5 can be changed with a smaller force.

[0093] When using the magnetic levitation motor of Embodiment 1, since the magnetic fields experienced by the upper and lower permanent magnet rotors 4 are the same, and the lever arms of the upper and lower permanent magnet rotors 4 are different, the torques of the upper and lower permanent magnet rotors 4 are different, which is not conducive to the stable rotation of the main shaft 5.

[0094] When using the magnetic levitation motor of Embodiment 2, since the magnetic field of the upper and lower permanent magnet rotors 4 is adjustable, even if the lever arms of the upper and lower permanent magnet rotors 4 are different, the torque of the upper and lower permanent magnet rotors 4 can be the same, which is more conducive to the stable rotation of 5.

[0095] The present invention has been described above by way of example, but the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A magnetic levitation motor, characterized by, include: The permanent magnet rotor (4), main shaft (5) and stator assembly are coaxial and arranged along the axial direction. The two permanent magnet rotors (4) are fixedly connected to the main shaft (5) respectively. The two permanent magnet rotors (4) have the same number of magnetic poles. The two stator assemblies are located outside the two permanent magnet rotors (4) respectively. The two stator assemblies drive the two permanent magnet rotors (4) to levitate and rotate through magnetic force respectively.

2. A magnetic levitation motor according to claim 1, characterized in that: The stator assembly includes a first magnetic yoke (1) and a coil group. The coil group is fitted outside the first magnetic yoke (1). The first magnetic yoke (1) and the coil group are evenly arranged around the permanent magnet rotor (4).

3. A magnetic levitation motor according to claim 2, characterized in that: The coil group includes a levitation coil (2) and a rotating coil (3). The levitation coil (2) and the rotating coil (3) are respectively mounted on the outside of the first magnetic yoke (1). The rotating coil (3) is used to drive the permanent magnet rotor (4) to rotate. The levitation coil (2) and the rotating coil (3) together drive the permanent magnet rotor (4) to levitate.

4. A magnetic levitation motor according to claim 2 or 3, characterized in that: The magnetic poles of the two permanent magnet rotors (4) are arranged in opposite directions.

5. A magnetic levitation motor according to claim 4, characterized in that: The two stator assemblies share a common first magnetic yoke (1) and coil group. The first magnetic yoke (1) includes an axial arm (11) and a radial arm (12). The two ends of the axial arm (11) are fixedly connected to the inwardly protruding radial arm (12). The two radial arms (12) of the same first magnetic yoke (1) are located on the outside of the two permanent magnet rotors (4). The coil group is fitted on the outside of the axial arm (11).

6. A magnetic levitation motor according to claim 2 or 3, characterized in that: The magnetic poles of the two permanent magnet rotors (4) are arranged in the same direction.

7. A magnetic levitation motor as claimed in claim 6, characterized in that: It also includes a second magnetic yoke (8), and the two stator assemblies share a first magnetic yoke (1). The first magnetic yoke (1) includes an axial arm (11) and a radial arm (12). The two ends of the axial arm (11) are fixedly connected to the inwardly protruding radial arm (12). The two radial arms (12) of the same first magnetic yoke (1) are located on the outside of the two permanent magnet rotors (4). The axial arm (11) passes through the second magnetic yoke (8). The coil groups of the two stator assemblies are respectively fitted on the outside of the axial arm (11) and located on the axial sides of the second magnetic yoke (8).

8. A magnetic levitation motor according to claim 7, characterized in that: The second magnetic yoke (8) is annular, and the main shaft (5) passes through the through hole inside the second magnetic yoke (8). The main shaft (5) is made of non-magnetic material. The first magnetic yoke (1) is in contact with and fixedly connected to the second magnetic yoke (8). It also includes a radial sensor and a controller, the radial sensor being used to detect the radial position of the spindle (5) and the controller being used to change the current in the coil group.

9. A magnetic levitation motor as claimed in claim 1, characterized in that: It also includes a housing (6), the stator assembly is located inside the housing (6) and fixedly connected to the housing (6), and the permanent magnet rotor (4) and the main shaft (5) do not contact the housing (6).

10. A pump using the magnetic levitation motor as claimed in claim 9, characterized by: It also includes a pump casing (7) and an impeller (73), the pump casing (7) being fixed to the housing (6), the pump casing (7) having an inlet (71) and an outlet (72) respectively, the permanent magnet rotor (4) and the main shaft (5) being located inside the pump casing (7), and the impeller (73) being fixedly connected to the permanent magnet rotor (4) and / or the main shaft (5).

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