CN115459489A - Passive diamagnetic suspension motor - Google Patents

Abstract

The invention discloses a passive diamagnetic suspension motor which comprises a suspension rotor, a permanent magnet synchronous driving system, a suspension magnet array and a support frame, wherein the suspension rotor is arranged on the support frame; the suspension rotor part comprises a permanent magnet rotor, a suspension turntable, an axial suspension permanent magnet, a rotating shaft and a shaft sleeve. The permanent magnet synchronous driving system comprises a coil winding and a first support, wherein three-phase current is introduced into the coil winding to generate a rotating magnetic field which is coupled with a permanent magnet rotor magnetic field so as to drive the motor rotor to rotate; the suspension magnet array comprises an upper suspension magnet array, a lower suspension magnet array, a permanent magnet array and a second support, wherein the permanent magnet array is arranged on the second support, and axial suspension force is provided for the suspension rotor, so that the suspension rotor part can be passively and stably suspended. The passive diamagnetic suspension motor overcomes the defect of small rotating torque caused by small electrostatic force of a diamagnetic suspension electrostatic motor, improves the driving capability of the motor, and solves the problem of low limit rotating speed caused by insufficient driving torque of electrostatic driving.

Description

A passive anti-magnetic levitation motor

technical field

Patent of the present invention The present invention discloses a novel passive anti-magnetic levitation motor, which belongs to the field of motors.

Background technique

Micro-electro-mechanical system (MEMS) integrates the functions of micro-mechanics and micro-electronics, and is widely used in high-tech industries such as micro-electronics, aerospace, sensors, and actuators. Key technologies for prosperity and national defense security. With the continuous development of MEMS technology, micro motors have become the core equipment of energy conversion, functional drive, and precision control in MEMS systems, and they shoulder the dual functions of precision drive and control in key fields such as micro robots, micro satellites, and biomedicine.

Antimagnetic levitation is a technology that uses the antimagnetism of diamagnetic substances to make it stably levitate in a magnetic field. It was first discovered in the 18th century. However, because the antimagnetic force itself is very weak, researchers did not conduct in-depth research on antimagnetic levitation at that time. Until the past 30 years, with the development of micro-manufacturing and strong magnetic field technology, the research and application of anti-magnetic levitation began to rise. Anti-magnetic levitation is not limited by Earnshaws theorem, and can achieve normal temperature, passive, frictionless, and statically stable levitation. The ratio of the anti-magnetic levitation force to the gravity of the suspended object is positively correlated with the surface area of the suspended object. Therefore, under the scale effect, the ratio of the levitation force to the gravity of the suspended object increases with the decrease of the scale. It has a great application prospect in the micro rotor.

At present, the anti-magnetic levitation motor is mainly divided into two categories according to the driving principle: one is the anti-magnetic levitation electrostatic motor driven by the interaction force between the induced charges. This kind of motor realizes the real non-contact drive of the stator and rotor. High power density. However, due to the use of the interaction force between induced charges for driving, its torque is small, and it is mainly used in the fields of micro gyroscopes and the like. The other is to use the traditional permanent magnet synchronous motor drive scheme under the premise of passive suspension of the rotor, and use the coil winding to drive the rotor attached with the permanent magnet to achieve the purpose of rotation. Compared with the electrostatic motor, although the volume of this motor is larger, its torque is also greater than the torque generated by the electrostatic force, and the movement of the rotor can be easily controlled only by controlling the amplitude and phase of the coil winding current.

Contents of the invention

Purpose of the invention: The present invention proposes a new type of passive anti-magnetic levitation synchronous motor aiming at the disadvantages of the existing electrostatic motors, such as small torque and difficult power transmission.

Technical solutions:

A passive anti-magnetic levitation motor, comprising a levitation rotor, a permanent magnet synchronous drive system, a levitation magnet array and a support frame, the levitation rotor includes a permanent magnet rotor, a levitation turntable, an axial levitation permanent magnet, a rotating shaft, and a shaft sleeve; The synchronous drive system includes coil windings, a first support, and the suspension magnet array includes an upper suspension magnet array, a lower suspension magnet array, a permanent magnet array, and a second support; the support frame includes a support base and an axial support rod; the permanent magnet rotor includes N magnetic tiles, N magnetic tiles are fixedly spliced on the rotating shaft, N is an even number greater than 4, there are two magnetization directions for the magnetic tiles, which are radial outward magnetization and radial inward magnetization, and the relative direction The magnetization direction of the permanent magnet magnetic tiles is the same, and the magnetization direction of the permanent magnet magnetic tiles in the adjacent direction is opposite; a coil winding is arranged outside the circumference of the permanent magnet rotor, and the coil winding is fixed on the first support, and the coil winding has three phases in total. The 3-phase sinusoidal alternating current is fed in, the frequency of the three-phase power is the same, the amplitude is the same, and the phase lags behind by 120° in turn, forming a rotating magnetic field and coupling with the magnetic field of the permanent magnet rotor, driving the permanent magnet rotor to rotate synchronously; since the three-phase power is a sinusoidal signal, And there is a sequential hysteresis relationship, so a rotating magnetic field traveling wave will be formed in the winding. Similar to the traditional permanent magnet synchronous motor, when the polarity of the rotating magnetic field is the same as that of the permanent magnet tiles on the rotor, a repulsive force is generated, and when it is the same polarity as the magnetic tiles, a suction force is generated. At this time, the rotor receives an unbalanced rotation. moment and start to rotate. Since the magnetic field of the excitation winding is in a state of continuous rotation, it will synchronously drive the rotor to rotate to achieve the purpose of driving; the suspension turntable is circular sheet-shaped, made of antimagnetic material, and the permanent magnet array is arranged in a ring Halbach, fixedly installed on the suspension turntable On the second support below, and opposite to the suspension turntable, there is a suspension air gap between the suspension turntable and the suspension turntable during operation, which is used to provide axial suspension force for the suspension turntable; the axial suspension permanent magnet is cylindrical, and the two axial suspension permanent magnets The magnets are installed on both ends of the rotating shaft through the shaft sleeve. The two axially suspended permanent magnets have the same polarity as the connecting end of the shaft sleeve. For example, the S pole of the axially suspended permanent magnet above the rotating shaft is upward and the N pole is downward. The N pole of the suspended permanent magnet is upward and the S pole is downward; the upper suspension magnet array and the lower suspension magnet array both include a disk-shaped bracket and M columnar permanent magnets, and M radially arranged cylindrical magnets are evenly arranged on the side of the disk-shaped bracket. The through hole is used to install M columnar permanent magnets, M is an even number greater than 4, and the polarity of the M columnar permanent magnets in the direction of the center of circle is the same as that of the shaft sleeve connection end of the axially suspended permanent magnet (3); if the installation method is The N pole is in the direction of the center of the circle, and the S pole is in the direction of the circumference. It fits with the through hole in a gap, and the middle is filled with fixing glue to ensure that the permanent magnets are firmly adhered; the upper floating magnet array and the lower floating magnet array provide upward axial force for the rotor. And the function of improving the radial stiffness to prevent the motor from destabilizing at high speed; 1. The suspended turntable is fixed, and there is a gap with the through hole at the center of the second support. The disc-shaped support of the upper suspension magnet array and the disc-shaped support of the lower suspension magnet array have a cylindrical through hole at the center of the circle. Above the rotating shaft The upper end of the axially suspended permanent magnet and the lower end of the axially suspended permanent magnet below the rotating shaft are located in the cylindrical through hole, and there is a gap with the circumference of the through hole; the axial support rod is fixed on the support base, and the disc-shaped bracket, the first Mounting holes are provided on the support and the second support, and the axial support rod connects the disc-shaped support of the upper suspended magnet array, the first support, the second support, and the disc-shaped support of the lower suspended magnet array through the mounting holes. fixed on the axial support rod.

Furthermore, the ring-shaped Halbach arrangement of the permanent magnet array is formed by nesting and splicing four permanent magnet rings with different magnetization directions. The magnetization directions of the permanent magnets from the inside to the outside are axially upward, radially inward, axial Downward and radial outward, ten circles are arranged in this way; the permanent magnets magnetized upward and downward in the axial direction build the lowest point of magnetic potential energy in the axial direction, so that the diamagnetic graphite rotor can be stable in the axial direction suspended. The permanent magnets magnetized in the radial direction play the role of magnetic concentration, thereby improving the radial stiffness of the rotor during passive suspension, and further improving the stability of the rotor during suspension and rotation.

Further, the centers of the levitation turntable and the permanent magnet array are concentric in the vertical direction, and the outer edge of the levitation turntable coincides with the junction of the eighth and ninth magnetic rings, which ensures that the levitation turntable is in the lowest magnetic potential energy of the magnetic field formed by the permanent magnet array point, and the magnetic permeability of pyrolytic graphite is very low. According to the principle of anti-magnetic levitation, the rotor can be stably suspended without external energy, and it has certain radial and axial stiffness.

Further, the number N of permanent magnet rotor magnetic tiles is 4.

Further, there are 8 through holes provided on the disc-shaped support, and the number of permanent magnets is 8

Further, the diamagnetic material of the suspended rotor may be pyrolytic graphite.

Further, the disk-shaped support in the suspension magnet array is an acrylic plate.

Further, the rotating shaft and the second support are made of ABS material. The second support is made of ABS material to avoid magnetic coupling with the permanent magnet array; the shaft is made of ABS material. ABS plastic is a kind of tough, hard and rigid material with easy-to-obtain raw materials, good comprehensive performance, cheap price and wide application , the mass of the rotor can be reduced on the premise of ensuring a substantial increase in rotor stiffness.

Further, the rotating shaft is a hollow structure.

Further, the number of axial support rods is four.

Beneficial effect:

The active rotation function of the anti-magnetic levitation motor is realized.

(1) The anti-magnetic levitation force of the anti-magnetic levitation motor is positively correlated with the rotor gravity ratio and the rotor surface area. Therefore, under the scale effect, the ratio of the levitation force to the rotor gravity increases as the scale decreases, which can realize the miniaturization of the motor.

(2) Anti-magnetic levitation is not limited by Earnshaws theorem, and without any energy input, it can achieve normal temperature, passive, frictionless, statically stable levitation.

(3) The annular levitation magnetic field is provided, which reduces the eddy current loss when the rotor rotates.

(4) It overcomes the disadvantage of small rotational torque caused by the small electrostatic force of the anti-magnetic levitation electrostatic motor, and improves the driving ability of the motor.

(5) It solves the shortcomings of low limit speed due to insufficient driving torque of electrostatic drive, and the electrical properties of materials are sensitive to environmental factors such as temperature and humidity, resulting in performance fluctuations.

(6) It is only necessary to adjust the amplitude and frequency of the three-phase electricity in the drive coil to change the speed of the motor, which is simple to control and sensitive to response.

Description of drawings

Fig. 1 Structural schematic diagram of anti-magnetic levitation synchronous motor;

Figure 2 Halbach permanent magnet array and suspended rotor cross-sectional structure diagram;

Figure 3 Schematic diagram of the magnetization direction of the Halbach permanent magnet array;

Figure 4 Schematic diagram of the 3D model of the lowest point of magnetic potential energy;

Fig. 5 schematic diagram of permanent magnet synchronous drive system;

Figure 6(a) is a schematic diagram of the upper suspended magnet array, and Figure 6(b) is a schematic structural diagram of the lower suspended magnet array;

Fig. 7 Top view of the structure of the motor levitation magnet array.

detailed description

The present invention will be further described below in conjunction with accompanying drawing:

The passive anti-magnetic levitation motor shown in Figure 1 includes a levitating rotor, a permanent magnet synchronous drive system, a levitating magnet array, and a support frame. The suspension rotor part includes a permanent magnet rotor 1, a suspension turntable 2, an axial suspension permanent magnet 3, a rotating shaft 4, and a shaft sleeve 5, and all components are fixedly connected. The permanent magnet synchronous drive system includes a coil winding 6 and a first support 7. The winding is fed with three-phase current to generate a rotating magnetic field, which is coupled with the magnetic field of the permanent magnet rotor to drive the rotor of the motor to rotate. The suspension magnet array includes an upper suspension magnet array 8, a lower suspension magnet array 9, a permanent magnet array 10, and a second support 11. The permanent magnet array 10 is nested and placed on the second support 11 for an annular Halbach permanent magnet array. The support 11 is made of acrylic material, which provides axial suspension force for the suspension rotor, so that the suspension rotor part can be passively and stably suspended; the upper suspension magnet array and the lower suspension magnet array are fixed on the support base through support rods, and the rotor is axially suspended. Serve as an auxiliary support. Since the rotor is passively suspended, the function of motor rotation can be realized only by feeding the driving current to the winding.

Fig. 2 is a cross-sectional structure diagram of Halbach magnet array and levitation rotor of passive anti-magnetic levitation motor. The specific magnetization direction of the magnetic ring in the magnet array is shown in Figure 3. The Halbach magnet array is composed of four permanent magnet rings with different magnetization directions. The magnetization directions from the inside to the outside are respectively Axially upward, radially inward, axially downward, and radially outward, arranged in ten circles according to this cycle. Among them, the permanent magnets magnetized upward and downward in the axial direction construct the lowest point of the magnetic potential energy in the axial direction, so that the antimagnetic graphite rotor can be stably suspended in the axial direction, while the permanent magnets magnetized in the radial direction play the role of magnetization , and then improve the radial stiffness of the rotor during passive suspension, so that the stability of the rotor in the process of suspension and rotation is further improved. The permanent magnet array 10 is fixedly installed on the second support 11, and is opposite to the suspension turntable 2, and has a suspension air gap with the suspension turntable 2 during operation, so as to provide axial suspension force for the suspension turntable; the second support 11 is composed of ABS Made of plastic to avoid magnetic coupling with the permanent magnet array.

A suspension disc 2 is placed above the permanent magnet array 10, and the suspension disc 2 is a diamagnetic material, which can be made of pyrolytic graphite. The center of the levitation turntable 2 is vertically concentric with the center of the permanent magnet array 10 . As shown in Figure 4, the analytical expression of the magnetic potential energy of the HALBACH magnet array is established, and a three-dimensional drawing is carried out. It can be seen from the figure that the lowest point of the magnetic potential energy is at A, which is located at the junction of the eighth and ninth magnetic rings. According to the anti-magnetic levitation mechanism, when the outer edge of the levitation turntable 2 coincides with the junction of the eighth and ninth magnetic rings, the graphite rotor is at the lowest point of the magnetic potential energy of the magnetic field formed by the permanent magnet array, and it can levitate stably. At the same time, it has a certain diameter. direction and axial stiffness.

The permanent magnet synchronous drive system consists of two parts: the permanent magnet rotor and the coil winding. As shown in Figure 5, the permanent magnet rotor includes four 1/4 ring-shaped magnetic tiles, and the four magnetic tiles are fixedly spliced on the ABS rod. The magnetic tiles have two magnetization directions, which are radially outward magnetization. and radially inwardly magnetized. When the permanent magnet rotor is spliced, the magnetization direction of the permanent magnet tiles in the opposite direction is the same, and the magnetization direction of the permanent magnet tiles in the adjacent direction is opposite. A coil winding 6 is arranged outside the circumference of the permanent magnet rotor 1, and the coil winding 6 is fixed on the first support 7. The coil winding 6 has three phases in total, and the three-phase sinusoidal alternating current V1, V2, V3 is fed in sequence. The three-phase electric V1, V2, V3 have the same frequency and the same amplitude, but the phase lags behind by 120°, forming a rotating magnetic field and coupling with the permanent magnet rotor magnetic field, thereby driving the rotor to rotate synchronously. Since the three-phase electricity is a sinusoidal signal and there is a sequential lag relationship, a rotating magnetic field traveling wave will be formed in the winding. Similar to the traditional permanent magnet synchronous motor, when the polarity of the rotating magnetic field is the same as that of the permanent magnet tiles on the rotor, a repulsive force is generated, and when it is the same polarity as the magnetic tiles, a suction force is generated. At this time, the rotor receives an unbalanced rotation. moment and start to rotate. Since the magnetic field of the excitation winding is in a state of continuous rotation, it will synchronously drive the rotor to rotate to achieve the purpose of driving

As shown in Figure 6(a) and Figure 6(b), the structure of the upper suspension magnet array and the lower suspension magnet array plays the role of providing upward axial force to the rotor and improving the radial stiffness, preventing the motor from In the case of instability, the upper levitation magnet array is composed of 8 axially magnetized columnar permanent magnets 15 mounted on the ABS disc-shaped support 14. As shown in FIG. 7 , the bracket is in the shape of a disk, and there are eight radially arranged cylindrical through-holes on the side for installing eight columnar permanent magnets 15 , and the eight cylindrical through-holes are equally spaced and symmetrically distributed. The columnar permanent magnet 15 is installed in such a way that the N pole is inward and the S pole is outward, and the through hole is a gap fit, and the middle is filled with fixing glue to ensure that the permanent magnet is firmly bonded. At the same time, two cylindrical axially suspended permanent magnets 3 are installed on both ends of the rotating shaft 4 through the shaft sleeve 5. The rotating shaft 4 is a hollow structure. The N pole of the lower axial suspension permanent magnet is upward and the S pole is downward. Because the magnetic poles attract in opposite directions and repel in the same direction, an interaction force will be generated between the axially suspended permanent magnet 3 fixed on the rotor and the columnar permanent magnet 15 on the disc-shaped support 12 . The resultant force on the axially suspended permanent magnet is decomposed into component forces in the X and Y directions. Since the columnar permanent magnets 15 on the disc-shaped support 12 are all symmetrically arranged, the resultant force of F _x is 0, and only F _y exists, and the direction of F _y is upward, which also plays a certain role in axially supporting the rotating shaft 4 . The suspended magnet array generates an upward resultant force Fy to the permanent magnets on the rotating shaft 4, which acts as an axial support for the rotor, and at the same time increases the radial stiffness to avoid the instability of the motor at high speed.

Rotating shaft 4 passes through the through hole at the center of the circle of the suspension turntable 2, the second support 11, and the permanent magnet rotor 1 successively from top to bottom, and is fixed with the permanent magnet rotor and the suspension turntable 2; The hole has a gap, and the disc-shaped support 14 of the upper suspension magnet array 1 and the disc-shaped support 14 of the lower suspension magnet array 2 have a cylindrical through hole at the center of circle, and the upper end of the axial suspension permanent magnet 3 above the rotating shaft 4 and The lower end of the axially suspended permanent magnet 3 below the rotating shaft 4 is located in the cylindrical through hole, and has a gap with the circumference of the through hole;

Four axial support rods 13 are fixed on the support base 12, and mounting holes are arranged on the disc-shaped support 14, the first support 7, and the second support 11, and the axial support rods 11 connect the upper suspension magnet array to the magnetic array through the mounting holes. The disc-shaped support 12 of 8, the first support 7, the second support 11, the disc-shaped support 12 of the lower suspended magnet array 9 are fixed on the axial support rod 13.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. A passive anti-magnetic levitation motor, characterized in that it comprises a levitation rotor, a permanent magnet synchronous drive system, a levitation magnet array and a support frame, and the levitation rotor comprises a permanent magnet rotor (1), a levitation turntable (2), a shaft Suspended permanent magnets (3), rotating shafts (4), and shaft sleeves (5); the permanent magnet synchronous drive system includes coil windings (6), a first support (7), and the suspended magnet array includes an upper suspended magnet array (8) , the lower suspended magnet array (9), the permanent magnet array (10), the second support (11); the support frame includes a support base (12) and an axial support rod (13); the permanent magnet rotor (1) includes N Fan-shaped magnetic tiles, N magnetic tiles are fixedly spliced on the rotating shaft (4), N is an even number greater than 4, and the magnetic tiles have two magnetization directions, namely radially outward magnetization and radially inward magnetization. The magnetization directions of the permanent magnet tiles in the same direction are the same, and the magnetization directions of the permanent magnet tiles in the adjacent direction are opposite; a coil winding (6) is arranged outside the circumference of the permanent magnet rotor (1), and the coil winding (6) is fixed on the first On the support (7), the coil winding (6) has three phases in total, and three phases of sinusoidal alternating current are fed in sequence, and the frequency of the three phases is the same, the amplitude is the same, and the phases are lagged by 120° in turn to form a rotating magnetic field and connect with the permanent magnet rotor (1 ) magnetic field coupling to drive the permanent magnet rotor (1) to rotate synchronously; the suspension turntable (2) is in the shape of a circular sheet made of antimagnetic material, and the permanent magnet array (10) is arranged in a ring Halbach arrangement, fixedly mounted on the suspension turntable ( 2) On the second support (11) below, and opposite to the suspension turntable (2), there is a suspension air gap with the suspension turntable (2) during operation; the axial suspension permanent magnet (3) is cylindrical, and the two shafts The suspended permanent magnets (3) are installed at both ends of the rotating shaft (4) through the shaft sleeves (5), and the polarities of the two axially suspended permanent magnets (3) and the connecting ends of the shaft sleeves (5) are the same; the upper suspension magnet array ( 8), the lower suspended magnet array (9) all includes a disk-shaped support (14), M columnar permanent magnets (15), and the side of the disk-shaped support (12) is evenly arranged with M radially arranged cylindrical through holes , used to install M columnar permanent magnets (15), M is an even number greater than 4, and fits with the through hole as a gap, and the middle is filled with fixing glue to ensure that the permanent magnets are firmly adhered, and the polarity of the M columnar permanent magnets in the direction of the center of the circle is consistent with the The polarities of the shaft sleeve connection ends of the axially suspended permanent magnet (3) are the same; The through hole is fixed with the permanent magnet rotor and the suspension turntable (2), and there is a gap with the through hole at the center of the second support (11). The center of the disc-shaped support (14) of the magnet array (2) is provided with a cylindrical through hole, the upper end of the axially suspended permanent magnet (3) above the rotating shaft (4) and the axially suspended permanent magnet below the rotating shaft (4) The lower end of (3) is located in the cylindrical through hole, and there is a gap with the circumference of the through hole; the axial support rod (13) is fixed on the support base (12), and the disc-shaped support (14 ), the first support (7), and the second support (11) are provided with mounting holes, and the axial support rod (11) connects the disk-shaped support (12) of the upper suspension magnet array (8) through the mounting holes, The first support (7), the second support (11), and the disk-shaped support (12) of the lower suspended magnet array (9) are fixed on the axial support rod (13). 2. A kind of passive anti-magnetic levitation motor according to claim 1, characterized in that, the permanent magnet array annular Halbach arrangement is formed by nesting and splicing four kinds of permanent magnet rings with different magnetization directions, from the inside to the outside The magnetization directions of the outer permanent magnets are respectively axially upward, radially inward, axially downward and radially outward, and are arranged in ten circles according to this cycle. 3. A kind of passive anti-magnetic levitation motor according to claim 1, characterized in that, the center of circle of the levitation turntable (2) and the permanent magnet array (10) is concentric in the vertical direction, and the outer edge of the levitation turntable (2) and The junction of the eighth and ninth magnetic rings coincides. 4. A passive anti-magnetic levitation motor according to claim 1, characterized in that the number N of permanent magnet rotor tiles is four. 5. A kind of passive anti-magnetic levitation motor according to claim 1, characterized in that, there are 8 through holes provided on the disc-shaped support (14), and the number of permanent magnets is 8. 6. A passive anti-magnetic levitation motor according to claim 1, characterized in that the anti-magnetic material of the levitation rotor can be pyrolytic graphite. 7. A passive anti-magnetic levitation motor according to claim 1, characterized in that the disk-shaped support (14) in the levitation magnet array is an acrylic plate. 8. A passive anti-magnetic levitation motor according to claim 1, characterized in that the rotating shaft (4) and the second support (3) are made of ABS material. 9. A passive anti-magnetic levitation motor according to claim 1, characterized in that the rotating shaft (4) is a hollow structure. 10. A novel passive anti-magnetic levitation motor according to claim 1, characterized in that the number of axial support rods (13) is four.

Images