Magnetic suspension motor capable of increasing control force and pump

Abstract

The invention relates to a magnetic suspension motor and pump capable of increasing control force, two permanent magnet rotors are coaxial and are arranged in the vertical direction, the two permanent magnet rotors are fixedly connected with a main shaft respectively, the number of magnetic poles of the two permanent magnet rotors is the same, the arrangement directions of the magnetic poles are opposite or the same, and 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, and the reinforcing coils of the two reinforcing windings are respectively and uniformly distributed around the two permanent magnet rotors in a circumferential mode. The reinforced windings are arranged on the outer sides of the upper permanent magnet rotor and the lower permanent magnet rotor, and when the main shaft moves axially, the reinforced windings provide extra magnetic pulling force for the main shaft, so that the main shaft is reset, and the axial deviation of the main shaft is reduced; when the main shaft does not generate axial deviation, the upper and lower reinforcing windings are electrified, and the magnetic fields generated by the reinforcing coils and the rotating coils are the same, so that the rotating driving force on the permanent magnet rotor is increased.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic levitation motors, in particular to a magnetic levitation motor and a pump with increased control force. 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, especially for thin-film magnetic levitation motors. The axial suspension of thin-film magnetic levitation motors is passively controlled, so the range of axial control force is small. Excessive axial load or violent fluctuations may cause suspension failure, which seriously limits the product's capability range in practical applications. Summary of the invention

[0005] The present invention aims to solve the above-mentioned problems and provides a magnetic levitation motor and a pump with increased control force, thereby solving the above-mentioned technical problems.

[0006] A magnetic levitation motor with increased control force comprises: a permanent magnet rotor, a main shaft, a casing, a reinforcing winding and a stator assembly, wherein two permanent magnet rotors are coaxial and arranged in the up-down 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 magnetic poles are arranged in opposite or the same direction, the two stator assemblies are respectively located outside the two permanent magnet rotors, the two stator assemblies drive the two permanent magnet rotors to suspend and rotate respectively through magnetic force, the stator assembly is fixedly connected to the casing, the reinforcing winding comprises a plurality of reinforcing coils, and the reinforcing coils of the two reinforcing windings are respectively arranged uniformly around the two permanent magnet rotors.

[0007] Furthermore, the stator assembly includes a first magnetic yoke and a coil group, the coil group is fixedly mounted on the outside of the first magnetic yoke, the first magnetic yoke and the coil group are evenly arranged around the permanent magnet rotor, and the reinforcement coil is fixedly connected to the first magnetic yoke.

[0008] Furthermore, the first magnetic yoke includes an axial arm and a first radial arm, the end of the axial arm is fixedly connected to the first radial arm, the first radial arm protrudes inward and is located radially outside the permanent magnet rotor, the coil group is wound around the outside of the axial arm, the reinforcement coil corresponds one-to-one to the first radial arm, and the reinforcement coil is located on the upper side and / or lower side of the corresponding first radial arm.

[0009] Furthermore, the two stator assemblies share the first yoke and the coil group.

[0010] Furthermore, the stator assembly also includes a second yoke, the two stator assemblies share the first yoke and the second yoke, the second yoke is located between the coil groups of the two stator assemblies and between the two reinforcement coils, the second yoke is annular, the main shaft passes through the through hole in the middle of the second yoke, and the first yoke passes through the second yoke in the up and down directions.

[0011] Furthermore, the axis of the reinforcement coil is perpendicular to the axis of the coil group, and the axis of the reinforcement coil is perpendicular to and intersects with the axis of the permanent magnet rotor.

[0012] Furthermore, the first magnetic yoke also includes a second radial arm, the second radial arm is in contact with and fixedly connected to the axial arm, and the reinforcement coil is sleeved on the outside of the second radial arm.

[0013] Further, when the reinforcing coil is located axially outside the two first radial arms, the axial arm is formed with an axial extension arm at its end, and the axial extension arm is located radially outside the reinforcing coil.

[0014] Furthermore, the main shaft is made of non-magnetic material.

[0015] A pump using the magnetic levitation motor also includes a pump casing and an impeller. The pump casing is fixed to the casing and inserted into the casing. 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. The impeller is fixedly connected to the permanent magnet rotor and / or the main shaft.

[0016] The present invention has the following advantages: 1. Enhanced windings are set on the outside of the upper and lower permanent magnet rotors. When the main shaft moves axially, the enhanced windings give the main shaft additional magnetic pulling force, thereby resetting the main shaft and reducing the axial deviation of the main shaft; 2. When the main shaft does not have axial deviation, you can choose to energize both the upper and lower enhancement windings. Because the magnetic field generated by the enhancement coil is the same as that of the rotating coil, the rotational driving force on the permanent magnet rotor is increased; 3. When the main shaft has no axial offset and the radial main control force is insufficient, the enhanced winding can also adopt the same control strategy as the suspension coil to generate the same magnetic field as the suspension coil, thereby enhancing the radial control force on the permanent magnet rotor; 4. The two stator assemblies correspond to a permanent magnet rotor respectively, forming 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; 5. 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

[0017] 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.

[0018] Figure 1 : Schematic diagram of magnetic pole change of rotating magnetic field (implementation method 1); Figure 2 : Schematic diagram of magnetic pole change of suspension magnetic field (implementation method 1); Figure 3 : A front cross-sectional view of the magnetic levitation motor (embodiment 1); Figure 4 : The second front cross-sectional view of the magnetic levitation motor (Implementation method 1); Figure 5 : A three-dimensional diagram of a magnetic levitation motor (implementation method 1); Figure 6 : Front cross-sectional view of the magnetic levitation pump (implementation method 1); Figure 7 :exist Figure 6 Schematic diagram of the cross-sectional structure at AA in the middle; Figure 8 : A three-dimensional diagram of a magnetic levitation pump; Fig. 9 : Schematic diagram of magnetic pole change of rotating magnetic field (implementation method 2); Fig.10 : Schematic diagram of magnetic pole change of suspension magnetic field (implementation method 2); Fig.11 : A front cross-sectional view of the magnetic levitation motor (Implementation Method 2); Fig.12 : The second front cross-sectional view of the magnetic levitation motor (Implementation Method 2); Fig.13 : Front cross-sectional view of the magnetic levitation pump (implementation method 2); Fig.14 :exist Fig.13 Schematic diagram of the cross-sectional structure at BB in the middle. DETAILED DESCRIPTION

[0019] 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.

[0020] 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.

[0021] 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. Embodiment 1: like Figures 1 to 14 As shown, a magnetic levitation motor with increased control force includes: a permanent magnet rotor 5, a main shaft 6, a casing 7, a reinforcement winding and a stator assembly, wherein the two permanent magnet rotors 5 are coaxial and arranged in the up and down directions, the two permanent magnet rotors 5 are respectively fixedly connected to the main shaft 6, and the two stator assemblies are respectively located outside the two permanent magnet rotors 5. The two stator assemblies drive the two permanent magnet rotors 5 to suspend and rotate respectively through magnetic force, the stator assembly is fixedly connected to the casing 7, and the reinforcement winding includes a plurality of reinforcement coils 4, and the reinforcement coils 4 of the two reinforcement windings are respectively arranged uniformly around the two permanent magnet rotors 5 in a circumferential manner.

[0022] Furthermore, the main shaft 6 is made of non-magnetic material, thereby avoiding the formation of an axial magnetic circuit between the two permanent magnet rotors 5 in the main shaft 6 .

[0023] Furthermore, an axial sensor and a controller are included, wherein the axial sensor is used to detect the axial position of the main shaft 6, and the controller is used to change the on and off of the current in the enhancement coil 4. The position of the main shaft 6 is detected by the axial sensor, and the detected position information is transmitted to the controller, which determines whether the enhancement coil 4 needs to be energized.

[0024] Furthermore, the stator assembly includes a first magnetic yoke 1 and a coil group, the coil group is fixedly mounted on the outside of the first magnetic yoke 1, the first magnetic yoke 1 and the coil group are evenly arranged around the permanent magnet rotor 5, and the reinforcement coil 4 is fixedly connected to the first magnetic yoke 1.

[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 one permanent magnet rotor 5. 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 5 to rotate, and the suspension coil 2 and the rotating coil 3 jointly drive the permanent magnet rotor 5 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.

[0027] It should be noted that the prior art of magnetically suspended bearingless motors is to drive permanent magnets to suspend and rotate by means of coil groups.

[0028] Furthermore, the two permanent magnet rotors 5 are identical.

[0029] Embodiment 1: The two permanent magnet rotors 5 have the same number of magnetic poles and are arranged in opposite directions. Figures 1 to 7 It should be noted that the two permanent magnet rotors 5 have the same structure, and the magnetic poles of the two permanent magnet rotors 5 are opposite in the axial direction by rotating them at a certain angle.

[0030] 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, the first magnetic yoke 1 includes an axial arm 10 and a first radial arm 11, the two ends of the axial arm 10 are respectively fixedly connected to the first radial arms 11 protruding inward, the two first radial arms 11 of the same first magnetic yoke 1 are respectively located on the outsides of the two permanent magnet rotors 5, and the coil group is sleeved on the outsides of the axial arms 10. The first radial arms 11 protrude inwardly, which can make the air gap between the first radial arms 11 and the permanent magnet rotor 5 smaller and reduce magnetic leakage.

[0031] Optionally, the two stator assemblies respectively include a first magnetic yoke 1 and a coil group, and the ends of the first magnetic yokes 1 of the two stator assemblies are in contact, so that the magnetic circuit can pass through the first magnetic yokes 1 of the two stator assemblies. The coil groups of the two stator assemblies are respectively sleeved on the outside of the first magnetic yokes 1 of their respective stator assemblies.

[0032] Furthermore, adjacent first yokes 1 are not connected by magnetic conductive materials, and adjacent yokes 1 refer to two circumferentially adjacent first yokes 1, so as to avoid a magnetic path passing through adjacent first yokes 1, thereby making the magnetic path pass through two symmetrical first yokes 1.

[0033] It should be noted that if Figure 3 As shown, Figure 3 When the reinforcing coils 4 of the upper and lower reinforcing windings are energized, the reinforcing windings at this time play the role of strong rotation driving force. Figure 4 As shown, during axial offset control, only one group of the reinforcement coils 4 of the upper and lower groups of reinforcement windings can have a magnetic circuit passing through, and the passing magnetic circuit needs to be closed within the first radial arm 11 of the first magnetic yoke 1 at the other end.

[0034] The suspension rotation principle of this embodiment is described by taking the example that each stator assembly includes 8 first magnetic yokes 1 and 8 coil groups, and the two stator assemblies share the same first magnetic yoke 1 and coil group, and each permanent magnet rotor 5 has 2 magnetic poles. It should be noted that this embodiment can actually meet the needs of magnetic suspension motors with different numbers of permanent magnet rotors 5 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 5. Since the present embodiment has two axially linearly arranged permanent magnet rotors 5, and the coaxial permanent magnet rotors 5 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 5 need to be staggered, that is, when the number of pole pairs of the permanent magnet rotor 5 is 1, the same magnetic poles of the double-layer permanent magnet rotor 5 are offset by 180°.

[0036] It should be noted that when the permanent magnet rotor 5 has M magnetic pole pairs, the same magnetic poles of the permanent magnet rotor 5 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 5 to rotate. The rotating magnetic field and the position change of the permanent magnet rotor 5 are shown as follows: Figure 1 shown.

[0038] in, Figure 1 The upper and lower layers are from a bird's-eye view. Figure 1 The "upper layer" refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 5, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 5, the angle below refers to the rotation angle of the permanent magnet rotor 5, the magnetic field within the circle is the magnetic field of the permanent magnet rotor 5, and the magnetic field outside the circle is the rotating magnetic field of the corresponding first radial arm 11.

[0039] The main magnetic circuit 14 in the radially symmetrical first magnetic yoke 1 is as follows Figure 3 As shown, the two stator assemblies together form a magnetic circuit. For the radial active suspension of the permanent magnet rotor 5, it is necessary to generate a two-pole magnetic field by controlling the power supply of the stator suspension coil 2, 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 5 is achieved by superimposing the suspension magnetic field on the rotating magnetic field. Among them, Figure 3 The magnetic poles of the permanent magnet rotor 5 in the upper middle portion are S on the left and N on the right, and the magnetic poles of the permanent magnet rotor 5 in the lower portion are N on the left and S on the right.

[0040] The change of the suspension magnetic field of the double-layer permanent magnet rotor 5 can be Figure 2 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 the double-layer permanent magnet rotors 5 need to participate simultaneously to form the main magnetic circuit 14 when a specific stator needs to work, the magnitude of the corrective force received by the two permanent magnet rotors 5 will be the same regardless of whether they are actively or passively suspended.

[0041] in, Figure 2 The upper and lower layers are from a bird's-eye view. Figure 2 The "upper layer" refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 5, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 5, the angle below refers to the rotation angle of the permanent magnet rotor 5, the magnetic field within the circle is the magnetic field of the permanent magnet rotor 5, 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 5 are coaxially spaced at both ends of the main shaft, compared with the magnetic suspension sheet motor with only one permanent magnet rotor 5 in the prior art, this structure can better suspend and rotate a relatively long shaft and output greater power.

[0043] Embodiment 2: The two permanent magnet rotors 5 have the same number of magnetic poles and the same magnetic pole arrangement direction, such as Figures 9 to 14 shown.

[0044] Furthermore, the first magnetic yoke 1 includes an axial arm 10 and a first radial arm 11 , the end of the axial arm 10 is fixedly connected to the first radial arm 11 , the first radial arm 11 protrudes inward and is located radially outside the permanent magnet rotor 5 , and the coil group is wound around the outside of the axial arm 10 .

[0045] Furthermore, the stator assembly also includes a second yoke 9, the two stator assemblies share the first yoke 1 and the second yoke 9, the second yoke 9 is located between the coil groups of the two stator assemblies and between the two reinforcement coils 4, the second yoke 9 is annular, the main shaft 6 passes through the through hole in the middle of the second yoke 9, and the first yoke 1 passes through the second yoke 9 in the up and down directions.

[0046] like Fig.11 As 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 5 of the upper layer, the upper half of the first magnetic yoke 1 on the right, and the second magnetic yoke 9 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 5 of the lower layer, the lower half of the first magnetic yoke 1 on the right, and the second magnetic yoke 9 respectively.

[0047] It should be noted that each independent main magnetic circuit 14 ( Fig.11 The magnetic field (with arrows in the middle) includes the superposition of two components: the rotating magnetic circuit generated by the rotating coil 3 and the levitation magnetic circuit generated by the levitation coil 2.

[0048] 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 5 to rotate. The rotating magnetic field and the position change of the permanent magnet rotor 5 are shown as follows: Fig. 9 shown.

[0049] in, Fig. 9 The upper and lower layers are from a bird's-eye view. Fig. 9 The "upper layer" refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 5, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 5, the angle below refers to the rotation angle of the permanent magnet rotor 5, the magnetic field within the circle is the magnetic field of the permanent magnet rotor 5, and the magnetic field outside the circle is the rotating magnetic field of the corresponding first radial arm 11.

[0050] For the radial active suspension of the permanent magnet rotor 5, 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 5 is achieved by superimposing the suspension magnetic field on the rotating magnetic field.

[0051] The position changes of the suspension magnetic field and the permanent magnet rotor 5 are as follows: Fig.10 As shown. Among them, Fig.10 The upper and lower layers are from a bird's-eye view. Fig.10 The "upper layer" refers to the magnetic field of the upper stator assembly and the upper permanent magnet rotor 5, the "lower layer" refers to the magnetic field of the lower stator assembly and the lower permanent magnet rotor 5, the angle below refers to the rotation angle of the permanent magnet rotor 5, the magnetic field within the circle is the magnetic field of the permanent magnet rotor 5, and the magnetic field outside the circle is the corresponding suspension magnetic field of the stator assembly.

[0052] 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.

[0053] It should be noted that, since the polarities of the axial magnetic poles of the two permanent magnet rotors 5 are the same, the polarities of the two first radial arms 11 of the same first magnetic yoke 1 are the same.

[0054] In this embodiment, the two stator assemblies can respectively generate different magnetic forces on the two permanent magnet shafts 5. Since the two permanent magnet rotors 5 are coaxially spaced at both ends of the main shaft, compared with the magnetic suspension sheet motor with only one permanent magnet rotor in the prior art, this structure can better suspend and rotate a relatively long shaft.

[0055] In most motors, since only one end of the main shaft 6 is connected to the load, the distances between the two permanent magnet rotors 5 and the force-bearing position of the main shaft 6 are different. When the radial external force on the main shaft 6 is small, the magnetic resistance between the permanent magnet rotor 5 and the stator assembly can suppress the deviation of the main shaft 6.

[0056] However, when the radial external force on the main shaft 6 is too large, external forces need to be applied at the upper and lower ends to suppress it, which requires different forces to be applied to the permanent magnet rotors 5 at both ends. In the presence of the second magnetic yoke 9, the radial control force is adjusted separately through two separate closed enhanced magnetic circuits 15 at the upper and lower ends, which is active control. Because the distances between the two permanent magnet rotors 5 and the load end are different, the force arms for applying radial forces are different. Applying a small radial force to the permanent magnet rotor 5 with a long force arm can produce the same control force as the permanent magnet rotor 5 with a short force arm, so the rational use of this difference can improve the efficiency of the motor.

[0057] 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 6, 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 5, so that the main shaft 6 is deflected.

[0058] Furthermore, the reinforcing coils 4 correspond to the first radial arms 11 one by one, and the reinforcing coils 4 are located on the upper side and / or the lower side of the first radial arms 11 corresponding thereto.

[0059] Furthermore, the axis of the enhancement coil 4 is perpendicular to the axis of the coil group, and the axis of the enhancement coil 4 is perpendicular to and intersects with the axis of the permanent magnet rotor 5 , so that the enhancement coil 4 applies axial magnetic pulling force to the permanent magnet rotor 5 .

[0060] There are several ways to position the two reinforcement windings: Mode 1: The reinforcing coils 4 of the two reinforcing windings are respectively located on the upper sides of their corresponding first radial arms 11 .

[0061] When the main shaft 6 deviates upward (i.e., the two permanent magnet rotors 5 move axially upward synchronously), the distance between the two permanent magnet rotors 5 and the corresponding enhancement windings decreases. If the enhancement windings are energized, the enhancement magnetic circuit 15 will pass through the permanent magnet rotor 5 and the enhancement windings, and the enhancement windings located above the permanent magnet rotor 5 will give the permanent magnet rotor 5 an upward magnetic pull, causing the permanent magnet rotor 5 to move upward, resulting in an increase in the axial displacement of the main shaft 6. Therefore, at this time, both enhancement windings are not energized to avoid increasing the axial displacement of the main shaft 6.

[0062] When the main shaft 6 deviates downward (i.e., the two permanent magnet rotors 5 move axially downward synchronously), the distance between the two permanent magnet rotors 5 and the corresponding enhancement winding increases. If the enhancement winding is energized, the enhancement magnetic circuit 15 will pass through the permanent magnet rotor 5 and the enhancement winding, and the enhancement winding located above the permanent magnet rotor 5 will give the permanent magnet rotor 5 an upward magnetic pull, causing the permanent magnet rotor 5 to move upward, thereby reducing the axial deviation of the main shaft 6. Therefore, at this time, both enhancement windings are energized to reduce the axial deviation of the main shaft 6.

[0063] This method is applicable to equipment where the main shaft 6 has a tendency to deviate axially downward, and both of the two enhanced windings can apply axial force to the corresponding permanent magnet rotor 5, and the ability to correct the downward deviation of the main shaft 6 is stronger. However, when the main shaft 6 deviates upward, the enhanced winding will increase the deviation when it is energized, so it is not applicable to equipment where the main shaft 6 has a tendency to deviate upward.

[0064] Mode 2: The reinforcing coils 4 of the two reinforcing windings are respectively located at the lower side of the corresponding first radial arms 11, such as Fig.12 shown.

[0065] When the main shaft 6 deviates upward (i.e., the two permanent magnet rotors 5 move axially downward synchronously), the distance between the two permanent magnet rotors 5 and the corresponding enhancement winding increases. If the enhancement winding is energized, the enhancement magnetic circuit 15 will pass through the permanent magnet rotor 5 and the enhancement winding, and the enhancement winding located below the permanent magnet rotor 5 will give the permanent magnet rotor 5 a downward magnetic pull, causing the permanent magnet rotor 5 to move downward, thereby reducing the axial deviation of the main shaft 6. Therefore, both enhancement windings are energized at this time to reduce the axial deviation of the main shaft 6.

[0066] On the contrary, when the main shaft 6 deviates downward, if the enhancement winding is energized, the enhancement winding will also give the permanent magnet rotor 5 a downward magnetic pull to move the permanent magnet rotor 5 downward, thereby increasing the axial displacement of the main shaft 6. Therefore, both enhancement windings are not energized at this time.

[0067] This method is suitable for equipment with a tendency of upward axial deviation of the main shaft 6. Both of the two enhanced windings can apply downward axial force to the corresponding permanent magnet rotor 5, and the ability to correct the upward deviation of the main shaft 6 is stronger. On the contrary, when the main shaft 6 deviates downward, the enhanced winding will increase the deviation when it is energized, so it is not suitable for equipment with a tendency of downward deviation of the main shaft 6.

[0068] Method 3: The reinforcing coils 4 of the two reinforcing windings are arranged opposite to each other (that is, the upper reinforcing coil 4 is located at the lower side of the upper first radial arm 11, and the lower reinforcing coil 4 is located at the upper side of the upper first radial arm 11), such as Figure 4 and Fig.11 As shown: When the main shaft 6 deflects upward, the upper enhancement winding is energized to exert a downward magnetic pull on the upper permanent magnet rotor 5. The lower enhancement winding is not energized at this time, because the magnetic field generated by the lower enhancement winding after energization will exert an upward magnetic pull on the lower permanent magnet rotor 5, which will in turn strengthen the deflection.

[0069] On the contrary, when the main shaft 6 deviates downward, the upper reinforcement winding is not energized, while the lower reinforcement winding is energized, giving the lower permanent magnet rotor 5 an upward magnetic pulling force, driving the main shaft 6 to move upward, thereby reducing the axial deviation.

[0070] In this embodiment, the two reinforcement windings are located between the two first radial arms 11, so the axial length is not increased, which is beneficial to reducing the space of the equipment.

[0071] It should be noted that when the reinforcing winding is energized in all the above methods, the direction of the reinforcing magnetic circuit 15 generated by the reinforcing coil 4 is the same as the direction of the corresponding main magnetic circuit 14. It should be noted that in the above methods, the magnetic field mainly passes through the first radial arm 11 but not through the reinforcing coil 4.

[0072] When the main shaft 6 does not produce axial deviation, the upper and lower reinforcing windings can be energized, because the reinforcing coil 4 and the corresponding rotating coil 3 generate the same magnetic field, which will increase the rotational driving force on the permanent magnet rotor 5; if the main shaft 6 does not have axial deviation and the radial main control force is insufficient, the reinforcing winding can also adopt the same control strategy as the corresponding suspension coil 2 to generate the same magnetic field as the suspension coil 2, thereby enhancing the radial control force; the reinforcing coil 4 can also use the single winding principle of the magnetic levitation motor, and pass a superimposed current into it, thereby generating a suspension and rotating magnetic field at the same time, and enhancing the rotation and radial suspension driving force.

[0073] Furthermore, the first magnetic yoke 1 further includes a second radial arm 12 , the second radial arm 12 is in contact with and fixedly connected to the axial arm 10 , and the reinforcement coil 4 is sleeved on the outside of the second radial arm 12 .

[0074] Preferably, the second radial arm 12 is formed integrally with the axial arm 10 .

[0075] Since the reinforcing coil 4 mainly utilizes the leakage magnetic flux of the permanent magnet rotor 5 and the added second radial arm 12 has better magnetic conductivity than the air in the original hollow space, the utilization rate of the leakage magnetic flux will be higher.

[0076] It should be noted that when the second radial arm 12 is not added and the reinforcing coil 4 is not energized, the axial suspension of the original main shaft 6 mainly relies on the passive suspension of the magnetic resistance of the permanent magnet rotor 5. Taking the upward displacement of the main shaft 6 as an example, at this time, the original upper first radial arm 11 and the lower first radial arm 11 will generate magnetic resistance due to the increase in air gap caused by the displacement of the permanent magnet rotor 5.

[0077] When the second radial arm 12 is added in the first method: When the main shaft 6 deviates upward, the distance between the two permanent magnet rotors 5 and the corresponding first radial arm 11 increases, and the distance between the two permanent magnet rotors 5 and the corresponding second radial arm 12 decreases. In order to suppress the magnetic field lines of the permanent magnet rotor 5 from passing through the corresponding second radial arm 12, the enhancement coils 4 of the two enhancement windings need to generate magnetic fields opposite to the corresponding rotating coils 3, respectively, to reduce the axial upward magnetic pulling force.

[0078] On the contrary, when the main shaft 6 deviates downward, the distances between the two permanent magnet rotors 5 and the corresponding first radial arm 11 and second radial arm 12 are increased. At this time, the two reinforcing coils 4 of the reinforcing windings need to generate the same magnetic field as the corresponding rotating coils 3, respectively, which enhances the upward magnetic pulling force on the permanent magnet rotor 5. This method has a better effect of suppressing the deflection of the main shaft 6 that tends to deviate downward.

[0079] When the second radial arm 12 is added in the second method: When the main shaft 6 deviates upward, the distances between the two permanent magnet rotors 5 and the corresponding first radial arm 11 and second radial arm 12 are increased. At this time, the enhancement coils 4 of the two enhancement windings need to generate the same magnetic field as the corresponding rotating coils 3, respectively, which enhances the magnetic pull on the permanent magnet rotor 5. This method has a better effect of suppressing the deviation of the main shaft 6 that tends to deviate upward.

[0080] On the contrary, when the main shaft 6 deviates downward, the distance between the two permanent magnet rotors 5 and the corresponding first radial arm 11 increases, and the distance between the two permanent magnet rotors 5 and the corresponding second radial arm 12 decreases. In order to suppress the magnetic force lines of the permanent magnet rotor 5 from passing through the corresponding second radial arm 12, the enhancement coils 4 of the two enhancement windings need to generate opposite magnetic fields (i.e., the magnetic circuit direction is opposite to that of the rotating coil 3) to reduce the axial downward magnetic pull.

[0081] When the second radial arm 12 is added in the third method: like Figure 4 , Figure 6 and Fig.13 As shown, a second radial arm 12 is added between the original two first radial arms 11. Taking the upward displacement of the main shaft 6 as an example, the distance between the upper permanent magnet rotor 5 and the first radial arm 11 and the second radial arm 12 at the upper end is increased. The second radial arm 12 at the upper end generates a magnetic pulling force due to the energization of the reinforcing coil 4, and the first radial arm 11 generates a magnetic resistance force, which jointly drive the upper permanent magnet rotor 5 to move downward and reset.

[0082] However, the magnetic resistance at the bottom will be different from that when the second radial arm 12 is not added, because the upward movement of the main shaft 6 makes the permanent magnet rotor 5 at the bottom away from the first radial arm 11 at the bottom, but close to the second radial arm 12 at the bottom. Therefore, relatively speaking, the magnetic resistance of the permanent magnet rotor 5 at the bottom has not increased, so the axial passive suspension effect at the lower end of the main shaft 6 will be weakened. This is because the magnetic circuit passing through the permanent magnet rotor 5 at the bottom will pass more through the second radial arm 12, and the magnetic flux passing through the first radial arm 11 is less, so the magnetic resistance of the first radial arm 11 to the permanent magnet rotor 5 is smaller.

[0083] Therefore, the control method of the enhancement coil 4 is different from that of the previous structure. When the main shaft 6 deviates upward, the control method of the enhancement coil 4 at the upper end remains unchanged (that is, the direction of the magnetic circuit is the same as that of the rotating coil 3 at the upper end), but the enhancement coil 4 at the lower end generates an opposite magnetic field (that is, the direction of the magnetic circuit is opposite to that of the rotating coil 3 at the lower end). This is mainly to suppress the magnetic lines of force of the permanent magnet rotor 5 at the lower end from closing through the second radial arm 12, thereby weakening the original axial passive suspension force.

[0084] It should be noted that, when the enhancement coil 4 is energized for active control, the permanent magnet rotor 5 is subjected to magnetic pulling force; components that are not energized for active control by the enhancement coil 4 (such as the first radial arm 11) provide the permanent magnet rotor 5 with magnetic resistance force.

[0085] Embodiment 2: like Figures 1 to 14 As shown, a pump using the magnetic levitation motor described in Example 1 also includes a pump casing 8 and an impeller 83, the pump casing 8 is fixed to the casing 7 and inserted into the inner cavity 70 of the casing 7, the pump casing 8 is respectively formed with an inlet 81 and an outlet 82, the permanent magnet rotor 5 and the main shaft 6 are located inside the pump casing 8, and the impeller 83 is fixedly connected to the permanent magnet rotor 5 and / or the main shaft 6.

[0086] An impeller 73 is fixedly arranged at one end of the main shaft 6, and the magnetic levitation motor is matched with the pump head to realize the work of pumping liquid medium, and the permanent magnetic force of the permanent magnet rotor 5 is larger than that of the magnetic levitation thin-film motor with a single permanent magnet of the same diameter shaft and a thickness equal to the sum of the two permanent magnet rotors 5 in the prior art, so the output power and torque of this embodiment are higher, which can better meet the needs of large flow or high lift.

[0087] Since the impeller 73 is subjected to an axial upward force when rotating in the liquid and tends to deviate upward, the position of the enhanced winding can be adopted in the second method (such as Figure 4 as shown) to enhance the downward magnetic pull and achieve a better correction effect.

[0088] In some cases, a smaller motor and pump are needed. In this case, the position of the enhanced winding can adopt the third method, where the added enhanced coil 4 is located between the two first radial arms 11, without increasing the volume of the motor and pump.

[0089] During operation, the main shaft 6 and the impeller 73 rotate synchronously, sucking the fluid from the inlet 81 and then pumping it out from the outlet 72. Since the main shaft 6 is subjected to the radial external force of the fluid at the end close to the impeller 83, the distances from the two permanent magnet rotors 5 to the location where the main shaft 6 is subjected to the radial external force of the fluid are different. When the radial external force on the main shaft 6 is small, the magnetic resistance between the permanent magnet rotor 5 and the stator assembly can suppress the deviation of the main shaft 6.

[0090] However, when the radial external force on the main shaft 6 is too large, external force needs to be applied at the upper and lower ends to suppress it, which requires different forces to be applied to the permanent magnet rotors 5 at both ends (the principle is described in Implementation Method 2). Since the lower permanent magnet rotor 5 is farther away from the force point of the main shaft 6, the lever arm is longer, which means that when the upper permanent magnet rotor 5 provides the same torque, the lower permanent magnet rotor 5 is subjected to less magnetic force. The difference in the magnitude of the magnetic force on the upper and lower permanent magnet rotors 5 can be achieved by changing the current and number of turns of the suspension coil 2 in different stator assemblies.

[0091] 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 with increased control force, characterized in that: include: A permanent magnet rotor (5), a main shaft (6), a casing (7), a reinforcement winding and a stator assembly, wherein the two permanent magnet rotors (5) are coaxial and arranged in the up-and-down direction, the two permanent magnet rotors (5) are respectively fixedly connected to the main shaft (6), the two permanent magnet rotors (5) have the same number of magnetic poles and the magnetic poles are arranged in opposite or the same directions, the two stator assemblies are respectively located outside the two permanent magnet rotors (5), the two stator assemblies respectively drive the two permanent magnet rotors (5) to suspend and rotate by magnetic force, the stator assembly is fixedly connected to the casing (7), the reinforcement winding comprises a plurality of reinforcement coils (4), and the reinforcement coils (4) of the two reinforcement windings are respectively arranged uniformly around the two permanent magnet rotors (5).

2. A magnetic levitation motor with increased control force according to claim 1, characterized in that: The stator assembly comprises a first magnetic yoke (1) and a coil group, the coil group being fixedly mounted on the outside of the first magnetic yoke (1), the first magnetic yoke (1) and the coil group being evenly arranged around the circumference of the permanent magnet rotor (5), and the reinforcing coil (4) being fixedly connected to the first magnetic yoke (1).

3. A magnetic levitation motor with increased control force according to claim 2, characterized in that: The first magnetic yoke (1) comprises an axial arm (10) and a first radial arm (11); the end of the axial arm (10) is fixedly connected to the first radial arm (11); the first radial arm (11) protrudes inwardly and is located radially outside the permanent magnet rotor (5); the coil group is wound on the outside of the axial arm (10); the reinforcing coil (4) corresponds to the first radial arm (11) one by one; the reinforcing coil (4) is located on the upper side and / or the lower side of the first radial arm (11) corresponding thereto.

4. The magnetic levitation motor with increased control force according to claim 2, characterized in that: The two stator assemblies share a first magnetic yoke (1) and a coil group.

5. The magnetic levitation motor with increased control force according to claim 2, characterized in that: The stator assembly further comprises a second magnetic yoke (9); the two stator assemblies share the first magnetic yoke (1) and the second magnetic yoke (9); the second magnetic yoke (9) is located between the coil groups of the two stator assemblies and between the two reinforcing coils (4); the second magnetic yoke (9) is annular; the main shaft (6) passes through a through hole in the middle of the second magnetic yoke (9); and the first magnetic yoke (1) passes through the second magnetic yoke (9) in the up-down direction; It also includes a radial sensor and a controller, wherein the radial sensor is used to detect the radial position of the main shaft (6), and the controller is used to change the current in the coil group.

6. The magnetic levitation motor with increased control force according to claim 2, characterized in that: The axis of the enhancement coil (4) is perpendicular to the axis of the coil assembly, and the axis of the enhancement coil (4) is perpendicular to and intersects with the axis of the permanent magnet rotor (5); It also includes an axial sensor and a controller, wherein the axial sensor is used to detect the axial position of the main shaft (6), and the controller is used to change the on and off of the current in the enhancement coil (4).

7. The magnetic levitation motor with increased control force according to claim 3, characterized in that: The first magnetic yoke (1) further comprises a second radial arm (12), the second radial arm (12) being in contact with and fixedly connected to the axial arm (10), and the reinforcing coil (4) being sleeved outside the second radial arm (12).

8. The magnetic levitation motor with increased control force according to claim 3, characterized in that: When the reinforcing coil (4) is located axially outside the two first radial arms (11), the axial arm (10) is formed with an axial extension arm (101) at its end, and the axial extension arm (101) is located radially outside the reinforcing coil (4).

9. The magnetic levitation motor with increased control force according to claim 1, characterized in that: The main shaft (6) is made of non-magnetic material.

10. A pump using the magnetic levitation motor according to any one of claims 1 to 9, characterized in that: The machine also comprises a pump casing (8) and an impeller (83); the pump casing (8) is fixed to the casing (7) and inserted into the casing (7); the pump casing (8) is respectively formed with an inlet (81) and an outlet (82); the permanent magnet rotor (5) and the main shaft (6) are located inside the pump casing (8); and the impeller (83) is fixedly connected to the permanent magnet rotor (5) and / or the main shaft (6).

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