Magnetic suspension motor and pump

Abstract

The magnetic suspension motor comprises permanent magnet rotors, a main shaft and two stator assemblies, the two permanent magnet rotors are coaxially 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, and the two stator assemblies are located on the outer sides of the two permanent magnet rotors respectively. The two stator assemblies respectively drive the two permanent magnet rotors to suspend and rotate through magnetic force. The two stator assemblies correspond to the permanent magnet rotors respectively, one or two independent magnetic circuits are formed, the total electromagnetic force borne by the permanent magnet rotors is improved, and therefore under the condition that the sizes of motors are the same, larger power is provided for the main shaft, and the flow and lift of the pump are improved.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic suspension bearingless motors, in particular to a magnetic suspension motor and a pump. Background Art

[0002] Traditional centrifugal pumps usually use mechanical bearings to support and position the rotor. This design is susceptible to problems such as bearing wear, lubricant failure and unreliable seals, and cannot 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 uses a magnetic field to suspend the impeller in the pump housing, thus achieving contact-free and wear-free operation. Compared with traditional mechanical bearing centrifugal pumps, magnetic levitation pumps have higher efficiency, longer life and lower maintenance costs.

[0004] Although magnetic levitation pumps have made significant progress, there are still some challenges in the existing technology. In particular, the thin-film magnetic levitation motor, the magnetic levitation pump driven by it 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 to the impeller, and the impeller applies radial external force to the main shaft. When the radial external force on the main shaft is small, the magnetic resistance between the permanent magnet rotor and the stator can suppress the deviation of the main shaft; however, when the radial external force on the main shaft is large, the stator needs to give the permanent magnet rotor additional magnetic force to suppress the deflection of the main shaft. The main shaft of the magnetic levitation motor used in the current magnetic levitation pump is only equipped with a permanent magnet rotor, resulting in a large deflection of the main shaft. Summary of the invention

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

[0007] A magnetic levitation motor comprises: a permanent magnet rotor, a main shaft and a stator assembly, wherein two permanent magnet rotors are coaxial and arranged along the axial direction, the two permanent magnet rotors are respectively fixedly connected to the main shaft, 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 drive the two permanent magnet rotors to suspend and rotate respectively through magnetic force.

[0008] Furthermore, the stator assembly includes a first magnetic yoke and a coil group, the coil group is sleeved on the outside of the first magnetic yoke, and the first magnetic yoke and the coil group are evenly arranged around the permanent magnet rotor.

[0009] Furthermore, the coil group includes a suspension coil and a rotating coil, the suspension coil and the rotating coil 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 suspension coil and the rotating coil jointly drive the permanent magnet rotor to suspend.

[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 group, wherein the first magnetic yoke includes an axial arm and a radial arm, wherein both ends of the axial arm are respectively fixedly connected to radial arms protruding inward, and the two radial arms of the same first magnetic yoke are respectively located on the outsides of the two permanent magnet rotors, and the coil group is sleeved on the outsides of the axial arms.

[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, and 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 radial arms protruding inward, the two radial arms of the same first magnetic yoke are respectively located on the outside of the two permanent magnet rotors, the axial arm passes through the second magnetic yoke, and the coil groups of the two stator assemblies are respectively mounted on the outside of the axial arm and are respectively located on both axial sides of the second magnetic yoke.

[0014] Furthermore, the second magnetic yoke is annular, the main shaft passes through a through hole inside the second magnetic yoke, and 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 casing, the stator assembly is located inside the casing and fixedly connected to the casing, and the permanent magnet rotor and the main shaft do not contact the casing.

[0016] A pump using the magnetic levitation motor also includes a pump casing and an impeller. The pump casing is fixed to the casing, and the pump casing is respectively formed with 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: 1. The two stator assemblies correspond to a permanent magnet rotor respectively, forming one or two independent magnetic circuits, which increases the total electromagnetic force on the permanent magnet rotor, thereby providing greater power to the main shaft under the condition of the same motor size, thereby increasing the flow rate and head of the pump; 2. The two independent magnetic circuits can change the magnetic forces acting on the two permanent magnet rotors respectively, so that when the main shaft is subjected to radial external force at one end close to the impeller, two forces of different sizes 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0019] Figure 1 : A schematic cross-sectional view of the magnetic levitation motor of the first embodiment; Figure 2 : Schematic diagram of magnetic pole change of rotating magnetic field in embodiment 1; Figure 3 : Schematic diagram of magnetic pole change of the suspension magnetic field of Example 1; Figure 4 : A schematic diagram of the three-dimensional structure of the magnetic levitation motor of Example 1 after removing the casing; Figure 5 : A schematic diagram of the cross-sectional structure of a magnetic levitation pump; Figure 6 :exist Figure 5 Schematic diagram of the cross-sectional structure at AA in the middle; Figure 7 : Schematic diagram of the three-dimensional structure of the magnetic levitation pump; Figure 8 : A schematic cross-sectional view of the magnetic levitation motor of the second embodiment; Fig. 9 : Schematic diagram of magnetic pole change of rotating magnetic field in embodiment 2; Fig.10 : Schematic diagram of magnetic pole change of the suspension magnetic field of Example 2; Fig.11 : A schematic diagram of the three-dimensional structure of the magnetic levitation motor of the second embodiment without the casing; Fig.12 : A schematic diagram of the three-dimensional structure of the magnetic levitation motor of the second embodiment after removing the casing and the main shaft; Fig.13 : The second schematic diagram of the cross-sectional structure of the magnetic levitation pump; Fig.14 :exist Fig.13 Schematic diagram of the cross-sectional structure at BB in the middle. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and examples: Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0023] Embodiment 1: like Figures 1 to 7 As shown, 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 respectively located outside the two permanent magnet rotors 4. The two stator assemblies drive the two permanent magnet rotors 4 to suspend and rotate respectively through magnetic force.

[0024] Furthermore, the stator assembly includes a first magnetic yoke 1 and a coil group, wherein the coil group is sleeved on the outside of the first magnetic yoke 1 , and the first magnetic yoke 1 and the coil group are evenly arranged around the permanent magnet rotor 4 circumferentially.

[0025] Each coil group can include one or more coils: Optionally, one coil group includes one coil. In this case, one coil provides a rotating magnetic field and a suspension magnetic field to the permanent magnet rotor 4. The structure using only one coil is simpler, but has higher requirements on the control system.

[0026] 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 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 suspension coil 2 and the rotating coil 3 jointly drive the permanent magnet rotor 4 to suspend.

[0027] Furthermore, the magnetic poles of the two permanent magnet rotors 4 are arranged in opposite directions.

[0028] The stator assembly can share components or be two separate stator assemblies that do not share components: Optionally, the two stator assemblies share a common first magnetic yoke 1 and a coil group, wherein the first magnetic yoke 1 includes an axial arm 11 and a radial arm 12, wherein both ends of the axial arm 11 are respectively fixedly connected to the radial arms 12 protruding inward, and the two radial arms 12 of the same first magnetic yoke 1 are respectively located on the outsides of the two permanent magnet rotors 4, and the coil group is sleeved on the outsides of the axial arms 11. The radial arms 12 protrude inwardly, which can make the air gap between the radial arms 12 and the permanent magnet rotor 4 smaller and reduce magnetic leakage.

[0029] Optionally, the two stator assemblies respectively include a first yoke 1 and a coil group, and the ends of the first yokes 1 of the two stator assemblies are in contact, so that the magnetic circuit can pass through the first yokes 1 of the two stator assemblies. The coil groups of the two stator assemblies are respectively sleeved on the outside of the first yokes 1 of various stator assemblies.

[0030] Furthermore, it also includes a casing 6 , the stator assembly is located inside the casing 6 and is fixedly connected to the casing 6 , and the permanent magnet rotor 4 and the main shaft 5 are not in contact with the casing 6 .

[0031] Furthermore, the main shaft 5 is made of non-magnetic material, so as to avoid the formation of an axial magnetic circuit between the two permanent magnet rotors 4 in the main shaft 5. Furthermore, adjacent first magnetic yokes 1 in the same stator assembly are not connected by magnetic conductive materials, and adjacent first magnetic yokes 1 refer to two circumferentially adjacent first magnetic yokes 1. This is because the two stator assemblies together form a magnetic circuit, and if two circumferentially adjacent first magnetic yokes 1 are connected by magnetic conductive materials, the magnetic circuit will be changed.

[0032] Furthermore, the number of magnetic pole pairs of each permanent magnet rotor 4 is 1.

[0033] Furthermore, the upper and lower permanent magnet rotors 4 are identical, and the upper and lower stator assemblies are identical.

[0034] like Figures 1 to 4 As shown, the suspension rotation principle of this embodiment is described by taking an example that each stator assembly has 8 first magnetic yokes 1 and 8 coil groups, and two stator assemblies share the same first magnetic yoke 1 and coil group, and each permanent magnet rotor 4 has 2 magnetic poles. It should be noted that this embodiment can actually meet the needs of motors with different numbers of permanent magnet rotors 4 with different numbers of magnetic poles and different numbers of coil groups.

[0035] For rotation, similar to a permanent magnet synchronous motor, the stator is usually required to excite a rotating magnetic field with the same number of poles as the permanent magnet rotor 4. Since the present embodiment has two axially linearly arranged permanent magnet rotors 4, and the coaxial permanent magnet rotors 4 are not connected by magnetic conductive materials, the first magnetic yoke 1 is C-shaped and the two adjacent first magnetic yokes 1 are not connected by magnetic conductive materials, in order to realize the rotating magnetic field, the magnetic pole positions of the double-layer permanent magnet rotor 4 need to be staggered, that is, when the number of pole pairs of the permanent magnet rotor 4 is 1, the same magnetic poles of the double-layer permanent magnet rotor 4 are offset by 180°.

[0036] 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.

[0037] Now let the rotating coils 3 groups of two adjacent first magnetic yokes 1 pass the same-direction current to generate an N-pole magnetic field at a certain moment. Then the rotating coils 3 groups of two radially symmetrical first magnetic yokes 1 should pass the opposite same-direction current to generate an 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 the current, the pair of magnetic fields can be rotated, thereby driving the permanent magnet rotor 4 to rotate. The rotating magnetic field and the position change of the permanent magnet rotor 4 are shown as follows: Figure 2 shown.

[0038] in, Figure 2 The upper and lower floors are both bird's-eye views. Figure 2 The "upper layer" 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 within 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.

[0039] The rotating magnetic field magnetic circuit in the radially symmetrical first magnetic yoke 1 is as follows Figure 1 As shown, the two stator assemblies together form a magnetic circuit. For the radial active suspension of the permanent magnet rotor 4, it is necessary to generate a two-pole magnetic field by controlling the power supply of the suspension coil 2 of the stator, which is a prior art in the field of magnetic suspension motors. The number of suspended 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 suspension magnetic field on the rotating magnetic field.

[0040] The change of the suspension magnetic field of the double-layer permanent magnet rotor 4 can be Figure 3 It is understood that except for the two radial degrees of freedom which are active suspension and axial rotation, the other degrees of freedom are passive suspension. Since a specific stator needs to work with the simultaneous participation of the double-layer permanent magnet rotor 4 to form the main magnetic circuit 13, the two permanent magnet rotors 4 will be subjected to the same corrective force regardless of whether they are actively or passively suspended.

[0041] in, Figure 3 The upper and lower floors are both bird's-eye views. Figure 3 The "upper layer" 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 within the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the corresponding suspension magnetic field of the stator assembly.

[0042] Since the two layers of permanent magnet rotors 4 are coaxially spaced at both ends of the main shaft, compared with the magnetic suspension thin-film motor with only one permanent magnet rotor 4 in the prior art, this structure can better suspend and rotate a relatively long shaft and output greater power.

[0043] Embodiment 2: like Figures 7 to 14 As shown, 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 respectively located outside the two permanent magnet rotors 4. The two stator assemblies drive the two permanent magnet rotors 4 to suspend and rotate respectively through magnetic force.

[0044] Furthermore, the stator assembly includes a first magnetic yoke 1 and a coil group, wherein the coil group is sleeved on the outside of the first magnetic yoke 1 , and the first magnetic yoke 1 and the coil group are evenly arranged around the permanent magnet rotor 4 circumferentially.

[0045] Each coil group can include one or more coils: Optionally, one coil group includes one coil. In this case, one coil provides a rotating magnetic field and a suspension magnetic field to one permanent magnet rotor 4. The structure using only one coil is simpler, but has higher requirements on the control system.

[0046] 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 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 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 in each coil group is greater, but the requirements for the control system are lower.

[0047] 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 the corresponding stator assembly to form an independent closed magnetic circuit, and each independent magnetic circuit is used for the suspension and rotation of the corresponding permanent magnet rotor 4. The same magnetic pole arrangement 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 above two magnetic poles is the same.

[0048] Furthermore, it also includes a second yoke 8, the two stator assemblies share a first yoke 1, the first 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 radial arms 12 protruding inward, the two radial arms 12 of the same first yoke 1 are respectively located on the outside of the two permanent magnet rotors 4, the axial arm 11 passes through the second yoke 8, the coil groups of the two stator assemblies are respectively sleeved on the outside of the axial arm 11 and are respectively located on both sides of the axial direction of the second yoke 8. The second yoke 8 plays a role of magnetic conduction, two independent magnetic circuits share one second yoke 8, and the two independent magnetic circuits both pass through the second yoke 8.

[0049] The radial arm 12 protrudes inward, so that the distance between the radial arm 12 and the permanent magnet rotor 4 can be closer and the air gap can be smaller, thereby reducing magnetic leakage.

[0050] Furthermore, the second magnetic yoke 8 is annular, the main shaft 5 passes through the through hole inside the second magnetic yoke 8, and 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 is in contact with the second magnetic yoke 8 and is fixedly connected.

[0051] Furthermore, a radial sensor and a controller are included, wherein the radial sensor is used to detect the radial positions 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. Different currents of the upper and lower suspension coils 2 are used to give different magnetic forces to the two permanent magnet rotors 4, so that the main shaft 5 is deflected.

[0052] Furthermore, it also includes a casing 6 , the stator assembly is located inside the casing 6 and is fixedly connected to the casing 6 , and the permanent magnet rotor 4 and the main shaft 5 are not in contact with the casing 6 .

[0053] Furthermore, the number of magnetic pole pairs of each permanent magnet rotor 4 is 1.

[0054] This embodiment takes the example that each stator assembly has 8 coil groups and each permanent magnet rotor 4 has two radially magnetized magnetic poles to explain the suspension and rotation principle of two permanent magnet rotors 4 corresponding to an independent magnetic circuit. It should be noted that the structure of two permanent magnet rotors 4 corresponding to a magnetic circuit in this embodiment is not only applicable to the permanent magnet rotor 4 with 8 first magnetic yokes 1 and two magnetic poles, but also applicable to the combination of a plurality of permanent magnet rotors 4 with different numbers of magnetic poles and different numbers of coil groups.

[0055] like Figure 8As shown, the coil group of the upper layer generates a magnetic flux potential, and the magnetic circuit of the upper layer passes through the upper half of the first magnetic yoke 1 on the left, the permanent magnet rotor 4 of the upper layer, the upper half of the first magnetic yoke 1 on the right, and the second magnetic yoke 8 respectively; the coil group of the lower layer generates a magnetic flux potential, and the magnetic circuit of the lower layer passes through the lower half of the first magnetic yoke 1 on the left, the permanent magnet rotor 4 of the lower layer, the lower half of the first magnetic yoke 1 on the right, and the second magnetic yoke 8 respectively.

[0056] It should be noted that each independent main magnetic circuit 13 ( Figure 8 The magnetic field (with arrows in the middle) includes two components: the rotating magnetic circuit generated by the rotating coil 3 and the levitation magnetic circuit generated by the levitation coil 2.

[0057] Now let the rotating coils 3 groups of two adjacent first magnetic yokes 1 pass the same-direction current to generate an N-pole magnetic field at a certain moment. Then the rotating coils 3 groups of the two radially symmetrical first magnetic yokes 1 (the same stator assembly) should pass the opposite same-direction current, so as to generate an 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 the current, the pair of magnetic fields can be rotated, thereby driving the permanent magnet rotor 4 to rotate. The rotating magnetic field and the position change of the permanent magnet rotor 4 are shown as follows: Fig. 9 shown.

[0058] in, Fig. 9 The upper and lower floors are both bird's-eye views. Fig. 9 The "upper layer" 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 within 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] For the radial active suspension of the permanent magnet rotor 4, it is necessary to generate a two-pair magnetic field by energizing the suspension coil 2 of the stator assembly, which is the existing technology in the field of magnetic suspension motors. The number of suspended magnetic pole pairs is equal to the number of rotating magnetic pole pairs ±1 pair, and the offset correction of the permanent magnet rotor 4 is achieved by superimposing the suspension magnetic field on the rotating magnetic field.

[0060] The position changes of the suspension magnetic field and the permanent magnet rotor 4 are as follows: Fig.10 As shown. Among them, Fig.10 The upper and lower floors are both bird's-eye views. Fig.10 The "upper layer" 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 within the circle is the magnetic field of the permanent magnet rotor 4, and the magnetic field outside the circle is the corresponding suspension magnetic field of the stator assembly.

[0061] Among them, except for the two radial degrees of freedom which are active suspension and axial rotation, the other degrees of freedom are passive suspension.

[0062] It should be noted that, since the polarities of the axial magnetic poles 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 the same.

[0063] In this embodiment, since the upper and lower layers can form a separate closed loop, Figure 8 The thickness and permanent magnetic force of the upper and lower layers of the permanent magnet rotor 4 can be different. The different permanent magnetic forces will cause the suspension forces on the two permanent magnet rotors 4 to be different. In view of the different force requirements at both ends of the main shaft 5 in actual situations, the thickness of the two permanent magnet rotors 4 can be set to be different, and the thickness of the corresponding radial arm 12 should also be adjusted with the change of the thickness of the permanent magnet rotor 4, so as to reduce unnecessary magnetic leakage caused by the inconsistent thickness of the permanent magnet rotor 4 and the radial arm 12.

[0064] During operation, the main shaft 5 rotates to drive the load to rotate, and the main shaft 5 is suspended to reduce friction. The two stator assemblies cooperate with the two permanent magnet rotors 4, which increases the power output of the main shaft 5 without changing the volume.

[0065] Embodiment three: like Figures 1 to 14 As shown, a pump using the magnetic levitation motor of embodiment one or embodiment two also includes a pump casing 7 and an impeller 73, wherein the pump casing 7 is fixed to the casing 6, and the pump casing 7 is respectively formed with an inlet 71 and an outlet 72, the permanent magnet rotor 4 and the main shaft 5 are located inside the pump casing 7, and the impeller 73 is fixedly connected to the permanent magnet rotor 4 and / or the main shaft 5.

[0066] During operation, the main shaft 5 and the impeller 73 rotate synchronously, sucking the fluid from the inlet 71 and then pumping it out from the outlet 72. Since the main shaft 5 is subjected to the radial external force of the fluid at the end close to the impeller 73, the distances from the two permanent magnet rotors 4 to the main shaft 5 subjected to the radial external force of the fluid are different. When the radial external force on the main shaft 5 is small, the magnetic resistance between the permanent magnet rotor 4 and the stator assembly can suppress the deviation of the main shaft 5.

[0067] However, when the radial external force on the main shaft 5 is too large, external force needs to be applied at the upper and lower ends to suppress it. Since the lower permanent magnet rotor 4 is far away from the force point of the main shaft 5, the lever arm is longer.

[0068] When the magnetic levitation motor of the first embodiment is used, since the upper and lower permanent magnet rotors 4 are subjected to the same magnetic field and have different force arms, the upper and lower permanent magnet rotors 4 have different torques, which is not conducive to the stable rotation of the main shaft 5.

[0069] When the magnetic levitation motor of the second embodiment is used, since the magnetic field of 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 torques of the upper and lower permanent magnet rotors 4 can be made the same, which is more conducive to the stable rotation of 5.

[0070] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications made based on the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A magnetic levitation motor, characterized in that: include: A permanent magnet rotor (4), a main shaft (5) and a stator assembly, wherein the two permanent magnet rotors (4) are coaxial and arranged along the axial direction, the two permanent magnet rotors (4) are respectively fixedly connected to 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), and the two stator assemblies drive the two permanent magnet rotors (4) to suspend and rotate respectively through magnetic force.

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

3. A magnetic levitation motor according to claim 2, characterized in that: The coil group comprises a suspension coil (2) and a rotating coil (3), wherein the suspension coil (2) and the rotating coil (3) are respectively mounted on the outside of the first magnetic yoke (1), and 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.

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: Two stator assemblies share a common first magnetic yoke (1) and a coil group, wherein the first magnetic yoke (1) comprises an axial arm (11) and a radial arm (12), the two ends of the axial arm (11) are respectively fixedly connected to the radial arms (12) protruding inwardly, 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 group is sleeved outside 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 according to claim 6, characterized in that: It also comprises a second magnetic yoke (8), the two stator assemblies share a first magnetic yoke (1), the first magnetic yoke (1) comprises an axial arm (11) and a radial arm (12), the two ends of the axial arm (11) are respectively fixedly connected to the radial arms (12) protruding inwardly, the two radial arms (12) of the same first magnetic yoke (1) are respectively located outside the two permanent magnet rotors (4), the axial arms (11) pass through the second magnetic yoke (8), and the coil groups of the two stator assemblies are respectively sleeved outside the axial arms (11) and respectively located on both axial sides of the second magnetic yoke (8).

8. The magnetic levitation motor according to claim 7, characterized in that: The second magnetic yoke (8) is annular, the main shaft (5) passes through a through hole inside the second magnetic yoke (8), and the main shaft (5) is made of a 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, wherein the radial sensor is used to detect the radial position of the main shaft (5), and the controller is used to change the current in the coil group.

9. The magnetic levitation motor according to claim 1, characterized in that: It also includes a casing (6), the stator assembly is located inside the casing (6) and is fixedly connected to the casing (6), and the permanent magnet rotor (4) and the main shaft (5) are not in contact with the casing (6).

10. A pump using the magnetic levitation motor as claimed in claim 9, characterized in that: The machine also comprises a pump casing (7) and an impeller (73), wherein the pump casing (7) is fixed to the casing (6), the pump casing (7) is respectively formed with an inlet (71) and an outlet (72), the permanent magnet rotor (4) and the main shaft (5) are located inside the pump casing (7), and the impeller (73) is fixedly connected to the permanent magnet rotor (4) and / or the main shaft (5).

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