A magnetic levitation motor and pump

Abstract

The application relates to a magnetic suspension motor and pump, which comprises a permanent magnet rotor, a main shaft and a stator assembly, two permanent magnet rotors are coaxial and arranged in the axial direction, the two permanent magnet rotors are fixedly connected with the main shaft respectively, the two permanent magnet rotors are of the same number of magnetic poles, 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 suspend and rotate through magnetic force. According to the application, the two stator assemblies correspond to one permanent magnet rotor respectively, one or two independent magnetic circuits are formed, the total electromagnetic force borne by the permanent magnet rotor is improved, and thus greater power is provided for the main shaft under the condition that the motor size is the same, and the flow and lift of the pump are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic levitation bearingless motor, and particularly relates to a magnetic levitation motor and a pump. BACKGROUND

[0002] Traditional centrifugal pumps usually use mechanical bearings to support and position the rotor, which is prone to problems such as bearing wear, lubricant failure, unreliable seals, and inability to meet ultra-clean requirements. In addition, traditional pumps have vibration and noise problems, and high operating costs. In order to overcome these shortcomings, magnetic levitation technology is widely used in the field of pumps.

[0003] Magnetic levitation technology suspends the impeller in the pump shell by using magnetic field, thereby realizing a contactless and wearless running state. Compared with traditional mechanical bearing centrifugal pumps, magnetic levitation pumps have higher efficiency, longer service life and lower maintenance cost.

[0004] Although magnetic levitation pumps have made significant progress, there are still some challenges in the existing technology. In particular, the thin-plate magnetic levitation motor, which drives the magnetic levitation pump, has bottlenecks for large flow delivery, such as low torque and poor stability during rotation.

[0005] The end of the main shaft of the magnetic levitation motor is fixedly connected with the impeller, and the impeller provides a radial external force to the main shaft. When the radial external force received by the main shaft is small, the magnetic resistance force between the permanent magnet rotor and the stator can suppress the deflection of the main shaft. However, when the radial external force received by the main shaft is large, the permanent magnet rotor needs additional magnetic force from the stator to suppress the deflection of the main shaft. The current magnetic levitation motor used in the magnetic levitation pump only has one permanent magnet rotor installed in the main shaft, resulting in a large deflection amplitude of the main shaft. SUMMARY

[0006] The present application aims to solve the above problems and provides a magnetic levitation motor and a pump, which solve the above technical problems.

[0007] A magnetic levitation motor comprises a permanent magnet rotor, a main shaft and a stator assembly, two permanent magnet rotors are coaxial and arranged in the axial direction, the two permanent magnet rotors are fixedly connected with the main shaft respectively, the number of magnetic poles of the two permanent magnet rotors is the same, 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 through magnetic force.

[0008] Further, the stator assembly comprises a first magnetic yoke and a coil group, the coil group is sleeved outside the first magnetic yoke, and the first magnetic yoke and the coil group are uniformly arranged in the circumferential direction 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 two permanent magnet rotors respectively, so that two different forces are applied to the two ends of the main shaft when the main shaft is subjected to radial external force near the impeller end, thereby reducing the deflection and deflection amplitude of the main shaft and improving the stability of the main shaft during rotation. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only one embodiment of the present application, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.

[0021] Figure 1 : cross-sectional structure schematic diagram of the magnetic suspension motor of embodiment one;

[0022] Figure 2 : schematic diagram of magnetic pole change of the rotating magnetic field of embodiment one;

[0023] Figure 3 : schematic diagram of magnetic pole change of the suspension magnetic field of embodiment one;

[0024] Figure 4 : three-dimensional structure schematic diagram of the magnetic suspension motor of embodiment one after removing the shell;

[0025] Figure 5 : cross-sectional structure schematic diagram of the magnetic suspension pump;

[0026] Figure 6 : cross-sectional structure schematic diagram at A-A in Figure 5

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

[0028] Figure 8 : cross-sectional structure schematic diagram of the magnetic suspension motor of embodiment two;

[0029] Figure 9 : schematic diagram of magnetic pole change of the rotating magnetic field of embodiment two;

[0030] Figure 10 : schematic diagram of magnetic pole change of the suspension magnetic field of embodiment two;

[0031] Figure 11 : three-dimensional structure schematic diagram of the magnetic suspension motor of embodiment two after removing the shell;

[0032] Figure 12 : three-dimensional structure schematic diagram of the magnetic suspension motor of embodiment two after removing the shell and the main shaft; ​

[0033] Figure 13 : cross-sectional structure schematic diagram of magnetic suspension pump

[0034] Figure 14 : cross-sectional structure schematic diagram of magnetic suspension pump Figure 13 at B-B in DETAILED DESCRIPTION

[0035] The application will be further described below in conjunction with the accompanying drawings and examples:

[0036] The embodiments of the present application will be described in detail below with reference to the drawings, in which the same or similar components have the same reference numerals throughout. The embodiments described below by way of examples are illustrative only, and are not to be construed as limiting the present application.

[0037] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0038] In the description of the present application, 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 shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation of the present application.

[0039] Example one:

[0040] As shown in Figures 1 to 7 , a magnetic suspension motor comprises a permanent magnet rotor 4, a main shaft 5 and a stator assembly, two permanent magnet rotors 4 are coaxial and arranged in the axial direction, two permanent magnet rotors 4 are fixedly connected with the main shaft 5 respectively, the number of magnetic poles of two permanent magnet rotors 4 is the same, two stator assemblies are respectively located outside two permanent magnet rotors 4, two stator assemblies respectively drive two permanent magnet rotors 4 to suspend and rotate through magnetic force.

[0041] Further, the stator assembly comprises a first magnetic yoke 1 and a coil group, the coil group is sleeved outside the first magnetic yoke 1, the first magnetic yoke 1 and the coil group are uniformly arranged in the circumferential direction around the permanent magnet rotor 4.

[0042] Each coil group can comprise one or more coils:

[0043] Optionally, one coil set includes one coil. In this case, the rotating magnetic field and the suspension magnetic field for the permanent magnet rotor 4 are provided by one coil. The structure with only one coil is simpler, but the control system is more demanding.

[0044] Optionally, the coil set includes the suspension coil 2 and the rotating coil 3, the suspension coil 2 and the rotating coil 3 are respectively sleeved outside the first magnetic yoke 1, the rotating coil 3 is used to drive the permanent magnet rotor 4 to rotate, and the suspension coil 2 and the rotating coil 3 jointly drive the permanent magnet rotor 4 to suspend.

[0045] Further, the magnetic pole arrangement directions of the two permanent magnet rotors 4 are opposite.

[0046] The stator assemblies can share components or be independent stator assemblies that do not share components:

[0047] Optionally, the first magnetic yokes 1 and the coil sets of the two stator assemblies are shared, the first magnetic yoke 1 includes an axial arm 11 and a radial arm 12, the axial arm 11 is fixedly connected with the inwardly protruding radial arm 12 at both ends, the two radial arms 12 of the same first magnetic yoke 1 are respectively located outside the two permanent magnet rotors 4, and the coil set is sleeved outside the axial arm 11. The radial arm 12 protrudes inwardly, which can make the air gap between the radial arm 12 and the permanent magnet rotor 4 smaller and reduce the magnetic leakage.

[0048] Optionally, the two stator assemblies respectively include the first magnetic yoke 1 and the coil set, the first magnetic yokes 1 of the two stator assemblies are in contact at the ends, so that the magnetic circuit can pass through the first magnetic yokes 1 of the two stator assemblies. The coil sets of the two stator assemblies are respectively sleeved outside the first magnetic yokes 1 of the respective stator assemblies.

[0049] Further, a housing 6 is further included, the stator assemblies are located inside the housing 6 and are fixedly connected with the housing 6, and the permanent magnet rotors 4 and the main shaft 5 are not in contact with the housing 6.

[0050] Further, the main shaft 5 is made of a non-magnetic conductive material, so as to avoid the formation of an axial magnetic circuit between the two permanent magnet rotors 4 in the main shaft 5

[0051] Further, the adjacent first magnetic yokes 1 in the same stator assembly are not connected by a magnetic conductive material, the adjacent first magnetic yokes 1 refer to the circumferentially adjacent two first magnetic yokes 1. This is because the two stator assemblies jointly form a magnetic circuit, and if the circumferentially adjacent two first magnetic yokes 1 are connected by a magnetic conductive material, the magnetic circuit will be changed.

[0052] Further, the number of pole pairs of each permanent magnet rotor 4 is 1.

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

[0054] As Figures 1 to 4 shown, with 8 first magnetic yokes 1 and 8 coil groups of each stator assembly 8, and the common first magnetic yokes 1 and coil groups of two stator assemblies, the principle of the suspension rotation of the embodiment is explained with an example of each permanent magnet rotor 4 having 2 magnetic poles. It should be noted that the embodiment can actually meet permanent magnet rotors 4 with different numbers of magnetic poles and motors with different numbers of coil groups.

[0055] For rotation, similar to permanent magnet synchronous motors, a stator is usually required to excite a rotating magnetic field with the same number of poles as the permanent magnet rotor 4. Since the embodiment is two axially linearly arranged permanent magnet rotors 4, and the coaxial permanent magnet rotors 4 are not connected by a magnetic conductive material, the first magnetic yoke 1 is C-shaped and the adjacent two first magnetic yokes 1 are not connected by a magnetic conductive material, so in order to make the rotating magnetic field available, the magnetic pole positions of the double-layer permanent magnet rotor 4 need to be offset, 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 magnetic pole pairs, the same magnetic poles of the permanent magnet rotor 4 are offset by 180° / M.

[0057] Now let the rotating coil 3 groups of certain two adjacent first magnetic yokes 1 pass through the same direction current, and at a certain moment produce N-pole magnetic field, then the rotating coil 3 groups of the radially symmetrical two first magnetic yokes 1 should pass through the opposite same direction current, so as to produce S-pole magnetic field at the same moment, at this moment a pair of required magnetic field for rotation is formed, through the phase change of the current, the pair of magnetic field realizes rotation, thereby driving the permanent magnet rotor 4 to realize rotation, the position change of the rotating magnetic field and the permanent magnet rotor 4 is shown in Figure 2 .

[0058] Among them, Figure 2 the upper layer and the lower layer are both from the perspective of looking down, Figure 2 the "upper layer" in the figure 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 angle of rotation of the permanent magnet rotor 4, the magnetic field in 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 magnetic circuit in the radially symmetrical first magnetic yoke 1 is shown in Figure 1 , and two stator assemblies together form a magnetic circuit. For the radial active suspension of the permanent magnet rotor 4, 2 pairs of magnetic poles are required to be generated by controlling the energization of the suspension coil 2 of the stator, which is prior art in the field of magnetic suspension motors. The number of magnetic pole pairs for suspension is equal to the number of rotating magnetic pole pairs ± 1 pair, and the offset correction of the permanent magnet rotor 4 is realized by the resultant magnetic field of the superposition of the suspension magnetic field on the rotating magnetic field.

[0060] The change of the suspension magnetic field of the double-layer permanent magnet rotor 4 can be achieved by Figure 3 It is understood that, in addition to the radial 2 degrees of freedom of active suspension and axial rotation, the rest of the degrees of freedom are passive suspension. Since the specific stator needs to work when the double-layer permanent magnet rotor 4 is simultaneously involved to form the main magnetic circuit 13, the correction force received by the two permanent magnet rotors 4, whether active or passive suspension, will be the same.

[0061] wherein, Figure 3 The upper layer and the lower layer of the double-layer permanent magnet rotor 4 are viewed from the top, Figure 3 The "upper layer" in the double-layer permanent magnet rotor 4 refers to the magnetic field of the upper-layer stator assembly and the upper-layer permanent magnet rotor 4, the "lower layer" refers to the magnetic field of the lower-layer stator assembly and the lower-layer permanent magnet rotor 4, the angle below refers to the angle of rotation 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 suspension magnetic field of the corresponding stator assembly.

[0062] Since the two-layer permanent magnet rotor 4 is coaxially and spaced apart at both ends of the main shaft, compared with the prior art of the magnetic suspension sheet motor with only one permanent magnet rotor 4, this structure can better suspend and rotate a relatively long shaft and output more power.

[0063] Embodiment two:

[0064] As shown in Figures 7 to 14 A magnetic suspension 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 in the axial direction. The two permanent magnet rotors 4 are fixedly connected with the main shaft 5. The two permanent magnet rotors 4 have the same number of magnetic poles. The two stator assemblies are respectively located outside the two permanent magnet rotors 4. The two stator assemblies respectively drive the two permanent magnet rotors 4 to suspend and rotate by magnetic force.

[0065] Further, the stator assembly includes a first magnetic yoke 1 and a coil group. The coil group is sleeved outside the first magnetic yoke 1. The first magnetic yoke 1 and the coil group are uniformly arranged in the circumferential direction around the permanent magnet rotor 4.

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

[0067] Optionally, one coil group includes one coil. At this time, one coil provides a rotating magnetic field and a suspension magnetic field for one permanent magnet rotor 4. The structure with only one coil is simpler, but the control system is required to be higher.

[0068] Optionally, the coil group includes a suspension coil 2 and a rotating coil 3. The suspension coil 2 and the rotating coil 3 are respectively sleeved outside the first magnetic yoke 1. The rotating coil 3 is used to drive the permanent magnet rotor 4 to rotate. The suspension coil 2 and the rotating coil 3 jointly drive the permanent magnet rotor 4 to suspend. In this way, the number of coils used by each coil group is larger, but the requirement of the control system is lower.

[0069] Further, the two permanent magnet rotors 4 have the same direction of magnetic pole arrangement. Each permanent magnet rotor 4 can form a closed magnetic circuit together with the corresponding stator assembly, and each closed magnetic circuit is used for the suspension and rotation of the corresponding permanent magnet rotor 4. The same direction of magnetic pole arrangement 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 two magnetic poles have the same polarity.

[0070] Further, the second magnetic yoke 8 is provided, and the two stator assemblies share the first magnetic yoke 1. The first magnetic yoke 1 includes an axial arm 11 and a radial arm 12. The axial arm 11 is fixedly connected to the inwardly protruding radial arm 12 at both ends. The two radial arms 12 of the same first magnetic yoke 1 are located on the outer sides 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 sleeved on the outer sides of the axial arm 11 and are respectively located on the axial two sides of the second magnetic yoke 8. The second magnetic yoke 8 has a magnetic guiding effect. The two independent magnetic circuits share the second magnetic yoke 8, and the two independent magnetic circuits pass through the second magnetic yoke 8.

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

[0072] Further, the second magnetic yoke 8 is annular. The main shaft 5 passes through the through hole in the interior of the second magnetic yoke 8. 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. The first magnetic yoke 1 is in contact with and fixedly connected to the second magnetic yoke 8.

[0073] Further, the radial sensor and the controller are provided. The radial sensor is used for detecting the radial positions of the upper and lower ends of the main shaft 5. The controller is used for changing the currents of the suspension coils 2 in the coil groups. The main shaft 5 is deflected by the magnetic forces of different sizes on the two permanent magnet rotors 4 due to the different current sizes of the upper and lower suspension coils 2.

[0074] Further, the machine shell 6 is provided. The stator assemblies are located in the machine shell 6 and are fixedly connected to the machine shell 6. The permanent magnet rotors 4 and the main shaft 5 are not in contact with the machine shell 6.

[0075] Further, the number of magnetic pole pairs of each permanent magnet rotor 4 is 1.

[0076] This embodiment takes an example of each stator assembly having 8 coil groups and each permanent magnet rotor 4 having two radially magnetized magnetic poles to explain the suspension and rotation principle of two permanent magnet rotors 4 corresponding to one independent magnetic circuit respectively. It should be noted that the structure of two permanent magnet rotors 4 corresponding to one magnetic circuit in this embodiment is not only applicable to the above-mentioned permanent magnet rotor 4 with 8 first magnetic yokes 1 and two magnetic poles, 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 magnetic potential, 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 magnetic potential, 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 Figure 8 includes two components of the rotating magnetic circuit generated by the rotating coil 3 and the suspension magnetic circuit generated by the suspension coil 2.

[0079] Now let the rotating coil 3 group of certain two adjacent first magnetic yokes 1 pass through the same current, and generate N-pole magnetic field at a certain moment. Then the rotating coil 3 group of the radially symmetrical two first magnetic yokes 1 (of the same stator assembly) should pass through opposite same direction current, so as to generate S-pole magnetic field at the same moment. At this time, a pair of magnetic fields required for rotation is formed. Through the phase change of current, the pair of magnetic fields realizes rotation, thereby driving the permanent magnet rotor 4 to realize rotation. The position change of the rotating magnetic field and the permanent magnet rotor 4 is shown in Figure 9 .

[0080] Among them, Figure 9 the upper layer and the lower layer are both from the perspective of top view, Figure 9 the "upper layer" in the figure 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 angle of rotation 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] For the radial active suspension of the permanent magnet rotor 4, 2 pairs of pole magnetic fields need to be generated by controlling the current passing through the suspension coil 2 of the stator assembly, which is the prior art in the field of magnetic suspension motor. The number of pairs of suspension magnetic poles is equal to the number of pairs of rotating magnetic poles ± 1. For the offset correction of the permanent magnet rotor 4, the resultant magnetic field of the suspension magnetic field superimposed on the rotating magnetic field is used to realize it.

[0082] The suspension magnetic field and the position change of the permanent magnet rotor 4 are shown in Figure 10 . Among them,Figure 10 Both the upper and lower levels are viewed from above. Figure 10 In this context, "upper layer" refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 4, "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 4, "lower angle" 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, because the upper and lower layers can form separate closed loops, Figure 8 The thickness and magnetic force of the two permanent magnet rotors 4 can be different. Different magnetic forces 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 differently. Simultaneously, the thickness of the corresponding radial arm 12 should be adjusted accordingly to reduce 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] like Figures 1 to 14 As shown, a pump using a magnetic levitation motor according to 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] During operation, the main shaft 5 and impeller 73 rotate synchronously, drawing fluid in through inlet 71 and pumping it out through outlet 72. Because the main shaft 5 experiences a radial fluid force at the end closest to impeller 73, the distances from the two permanent magnet rotors 4 to the point on the main shaft 5 where the radial fluid force is applied 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 main shaft 5 from deflecting.

[0090] But when the radial external force on the main shaft 5 is too large, the external force needs to be applied on the upper and lower ends to restrain it. Since the lower permanent magnet rotor 4 is far from the force point of the main shaft 5, the force arm is longer.

[0091] When the magnetic suspension motor of example one is used, since the magnetic field on the upper and lower permanent magnet rotors 4 is the same, and the force arms of the upper and lower permanent magnet rotors 4 are different, the torque of the upper and lower permanent magnet rotors 4 is different, which is not conducive to the stable rotation of the main shaft 5.

[0092] When the magnetic suspension motor of example two is used, since the magnetic field on the upper and lower permanent magnet rotors 4 is adjustable, even if the force 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 the main shaft 5.

[0093] The above has described the present application by way of example, but the present application is not limited to the above specific examples, and any modification or change made based on the present application falls within the scope of the present application.

Claims

1. A magnetic levitation motor, characterized in that, include: The permanent magnet rotor (4), the main shaft (5) and the 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. 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). The magnetic poles of the two permanent magnet rotors (4) are arranged in the same direction; 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). The second magnetic yoke (8) is ring-shaped, 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) contacts and is fixedly connected to the second magnetic yoke (8).

2. A magnetic levitation motor according to claim 1, 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.

3. A magnetic levitation motor according to claim 1, characterized in that: 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 assembly.

4. A magnetic levitation motor according to 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).

5. A pump using the magnetic levitation motor as described in claim 4, characterized in that: 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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