CN114069947A - Many rotor unmanned aerial vehicle magnetic suspension driving motor - Google Patents

Abstract

The magnetic suspension technology of the driving motor in the multi-rotor unmanned aerial vehicle power system disclosed by the invention enables the lift force generated in the rotor of the unmanned aerial vehicle to be transmitted to the unmanned aerial vehicle body in the form of magnetic suspension force without transmitting force through a motor bearing, so that the friction force and friction loss in the bearing are eliminated, the driving efficiency of the motor is improved, the magnetic suspension force and the lift force are balanced at random, and a controller is not needed, so that the manufacturing cost of the magnetic suspension motor is equivalent to that of the traditional non-magnetic suspension motor, and the magnetic suspension motor is relatively easy to manufacture.

Description

Many rotor unmanned aerial vehicle magnetic suspension driving motor

Technical Field

The invention belongs to the technical field of unmanned aerial vehicles, and particularly provides a motor-driven power device with magnetic suspension characteristic for a multi-rotor unmanned aerial vehicle and an implementation method thereof.

Background

In the unmanned aerial vehicle field, many rotor unmanned aerial vehicle are a kind that uses extensively. Many rotor unmanned aerial vehicle also called multiaxis unmanned aerial vehicle, unmanned aerial vehicle provides power by the motor that becomes the logarithm, the power device that an installation rotor constitutes on every motor shaft, driving motor provides the power that the rotor called the paddle is rotatory, install the rotor of unmanned aerial vehicle motor epaxial and push down the air, the rotor also can receive an axial reaction force of air simultaneously, this reaction force is exactly the lift on the rotor, but only lift on the rotor shifts to the stator body, when the unmanned aerial vehicle organism promptly, just can really become unmanned aerial vehicle's lift, the medium of this power transmission is exactly the bearing between the motor stator rotor. The sum of the lift force obtained by each motor is equal to or greater than the gravity of the unmanned aerial vehicle, and the unmanned aerial vehicle can overcome the influence of the gravity to lift off and stay in the air.

Since the bearings have friction force under the action of the rotating speed, when the motor rotates, particularly at high speed, great friction force and friction loss are generated in the bearings, and the bearings generate heat. The heat dissipation and lubrication of the bearing also become one of the key technologies influencing the long-term normal operation of the motor. For this reason, the quality of bearing products is receiving the attention of unmanned aerial vehicle motor manufacturers.

The magnetic suspension bearing avoids the friction factor by a non-contact structure, and is an important alternative structure for solving the friction problem of the traditional bearing. However, the existing magnetic levitation motor usually adopts an active magnetic levitation technology, a complex control system must be used to adjust the exciting current in each direction, additional control energy consumption is also increased, the efficiency of the driving system is reduced, and the controller needs to be provided with a plurality of sensors and complex control devices, and electromagnetic coils or even software overhead, so the cost of the whole control system is very high, and the high-tech magnetic levitation technology is difficult to enter the field of the traditional motor.

Disclosure of Invention

The invention aims to excavate and utilize the potential of the motor by technical innovation, utilize the potential of the existing magnetic field structure in the motor on the premise of not adding any device, realize dual purposes of one magnetic field, support the electromechanical energy conversion of the motor, change electric energy into mechanical energy, provide the lift force of the unmanned aerial vehicle, and additionally generate a follow-up magnetic suspension force to realize a simple magnetic suspension structure without a controller, fundamentally reduce the cost of the magnetic suspension structure, reduce and even eliminate the friction loss in a bearing, greatly reduce the high cost of the traditional magnetic suspension motor which must be paid by the active magnetic suspension technology while improving the mechanical performance and the efficiency of a unit, and further ensure that the unmanned aerial vehicle driven by the magnetic suspension motor obtains high cost performance.

The device is realized in such a way that a magnetic suspension driving motor device mainly used for a multi-rotor unmanned aerial vehicle is a traditional radial magnetic field structure consisting of a stator, a rotor, a bearing and the like, armature windings are embedded in laminated tooth grooves of a stator magnetic circuit, a double number of magnets are installed on the surface of the rotor, magnetic poles of adjacent magnets are arranged in a different polarity mode, magnetic lines of force flow through a stator magnetic yoke from one magnetic pole in the radial direction of the motor and return to the other two different polarity poles on two sides of the rotor from the other magnetic poles in the radial direction of the motor, and then a magnetic line of force loop is completed through a rotor magnetic yoke.

These structures make the rotor produce the lift in the pivot, through the magnetic levitation power and no longer transmit motor stator body and unmanned aerial vehicle organism as traditional thrust bearing's bearing capacity through the bearing to frictional force and friction loss in the motor bearing are alleviateed or even eliminated.

The unmanned aerial vehicle magnetic suspension driving motor has the advantages that the structure of the unit is almost the same as that of the traditional permanent magnet motor, the difference is only small difference in the bearing, the technical principle is very simple, the motor function is realized by depending on the magnetic field of the motor, the axial magnetic suspension force is generated by one field for two purposes, the motor can be automatically balanced with the lifting force of the unmanned aerial vehicle, the magnetic suspension force can be used for overcoming the influence of the gravity of the unmanned aerial vehicle, the magnetic suspension force and the gravity are kept in random balance, an additional controller is not needed, the friction force is reduced or even close to zero, the mechanical efficiency of the motor is improved, the friction heating in the bearing is reduced, the heat dissipation problem of the bearing is relieved, the lubrication and maintenance cost of the bearing is reduced, the service life of the unit is prolonged, and the like. On the contrary, the cost of the unit is quite low, compared with the existing complex magnetic suspension bearing, the cost is greatly reduced, the energy consumption of the traditional magnetic suspension controller and the electromagnet is avoided, the driving efficiency of the unit is improved, and the limited airborne electric energy can maintain longer unmanned aerial vehicle dead time or working time.

Drawings

FIG. 1 is a schematic diagram of the structural principle of an active magnetic suspension air compressor

FIG. 2 is a schematic view of a passive magnetic suspension vertical axis wind turbine

FIG. 3 is a simplified diagram of a non-magnetic levitation drive motor of a conventional multi-rotor unmanned aerial vehicle

The meanings marked in the drawings are as follows:

1: the rotor of the motor is provided with a rotor,

2: a stator of the motor is arranged on the stator,

3: a bearing of the motor is arranged on the bearing,

4: a rotating shaft of the motor is provided,

5: the end cover of the motor is provided with a motor end cover,

6: motor function portion, wherein, 61: magnet on rotor, 62: and a winding on the stator.

FIG. 4 is a static force diagram of the drive motor of a multi-rotor drone of the present invention

FIG. 5 force diagram of motor rotation

FIG. 6 is a schematic view of a special two-degree-of-freedom bearing of the present invention

The meanings marked in the drawings are as follows:

31: an inner ring of a bearing of the motor is provided,

32: the ball bearings of the motor are arranged on the bearing,

33: and a motor bearing outer ring.

FIG. 7 is a schematic view of a two-degree-of-freedom bearing with a recessed groove outer ring according to the present invention

The meanings marked in the drawings are as follows:

34: the motor bearing outer ring is provided with a concave groove.

Fig. 8 shows the protrusions on the inner ring of the motor bearing of the present invention.

The meanings marked in the drawings are as follows:

35: convex groove on inner ring of motor bearing

Detailed Description

Unmanned aerial vehicle is the extension of human sense organ and four limbs, has very big application prospect, for example through unmanned aerial vehicle, can observe sound and image far away, is equivalent to the extension of human ear and eyes, and passes through the aerial transmission of unmanned aerial vehicle with article, is equivalent to the extension of human hand and foot again, has replaced the transportation work of people. The multi-rotor unmanned aerial vehicle can lift off, suspend in the air or walk in the air, and the lift force generated by the rotation of the rotor driven by the driving motor is completely depended on, and the lift force is similar to the lift force generated by the blades of the helicopter.

During mechanical movement, the motor shaft is typically subjected to radial and axial external forces that can cause friction between the components in relative motion, which is difficult to overcome. Between the rotating bodies, friction is exerted in the bearing, and the friction is eliminated unless the bearing is removed.

Gravity friction almost appears in each motor bearing, but the only feasible method that can remove the traditional bearing in the atmosphere of earth gravity action is to suspend the rotating shaft in the air by magnetic suspension force, which is the active magnetic suspension technology, and the active magnetic suspension technology usually utilizes the magnetic force generated by magnetic attraction to resist external force, so as to achieve the purpose of no need of the traditional bearing, so the active magnetic suspension is also called as attraction type magnetic suspension.

However, active magnetic levitation is not easy to use electromagnetic force to make the rotor levitate at a certain spatial position. The relative position of the rotor must be detected by a stator side sensor, and the size of exciting current in the electromagnet powered by an independent external power supply is controlled by a controller, so that the proper magnetic levitation force is formed to balance the action of the external force, and the effect of spindle levitation is achieved. However, the added component cost of such a magnetic levitation structure can be many times higher than the manufacturing cost of the conventional motor itself.

Taking the schematic structural principle of the active magnetic suspension air compressor shown in fig. 1 as an example, the magnetic suspension motor needs to be provided with a radial magnetic suspension bearing controlled by a magnetic suspension controller at each of two ends of the bearing except for the radial external force. The rotating shaft is also acted by axial external force, so that a group of axial magnetic suspension bearings are arranged on the rotating shaft at the upper part of the motor armature, an upper group and a lower group of electromagnets are contained in the axial magnetic bearing bearings, the current in the axial electromagnets is controlled by a magnetic suspension bearing controller, and a sensor is also required to detect the axial position so as to keep the positioning of the magnetic bearing. Therefore, the position of the rotating shaft is controlled to be at a preset relative spatial position through proper magnetic force, the rotor is suspended in the air and is not in contact with the stator any more, a mechanical bearing is not needed, any friction force does not exist, and active magnetic suspension is realized by an external power supply through electromagnetic force generated by a controller and an electromagnet to keep the rotating shaft at a set and non-contact spatial position. Obviously, the active magnetic suspension must be provided with an external power supply to provide enough control current, and the unit of the active magnetic suspension, the plurality of magnetic suspension bearing controllers, the plurality of sensors and the electromagnets is always higher in cost than the original motor. Therefore, the cost of the magnetic suspension motor is greatly improved, the cost performance of the magnetic suspension motor is greatly reduced, and the magnetic suspension motor is not accepted by the market, so that the magnetic suspension technology cannot enter the field of traditional motor products.

More advanced active magnetic suspension is characterized in that an armature winding of an alternating current motor is regarded as an electromagnet, when alternating current driving current is input into the winding, magnetic suspension control current is input to enable a rotating shaft to be suspended in the air to rotate in a non-contact mode, extra electromagnets are omitted, and a sensor and a controller cannot or are not available.

Another large class of structures corresponding to active magnetic levitation structures is passive magnetic levitation.

Taking the passive magnetic suspension vertical axis wind turbine shown in fig. 2 as an example, passive magnetic suspension generates a magnetic suspension effect by the same-polarity repulsion between magnets, and only a pair of magnets with the same polarity repelling each other is needed to generate the required magnetic suspension force to overcome the gravity of the rotor without a stack of complex control electromagnets. Because only the repulsive force of the same poles repelling each other can generate stable magnetic levitation force. Theoretically, when the rotor has three pairs of magnets in a three-dimensional space, full magnetic levitation force can be generated to remove the bearing, but the full magnetic levitation force cannot be generated in practice, so that one to two-dimensional magnetic levitation force still needs to be provided by the bearing, and the other dimensions still keep mechanical constraint, so that the friction force on some limited dimensions can be reduced, and the rotor is called as a semi-magnetic levitation structure.

According to the analysis, due to the reasons of cost performance and the like, the existing active magnetic suspension technology and passive magnetic suspension technology are difficult to enter the field of unmanned aerial vehicle driving motors, and people have to get back to the basic structure of the driving motor again to find technical breakthrough again.

Before the magnetic suspension structure of the invention is not discussed, it is necessary to know the stress condition of the bearing in the traditional drive motor of the unmanned aerial vehicle.

Fig. 3 is a schematic diagram of a non-magnetic suspension driving motor for a multi-rotor unmanned aerial vehicle.

According to conventional design, unmanned aerial vehicles often adopt vertical axis permanent magnet motors. The motor main body: the axial length of the stator (2) is equal to that of the rotor (1), an armature winding is embedded in a stator magnetic circuit tooth slot, magnets are distributed on the surface of the rotor close to the stator to form magnetic poles, the basic structure of the rotor is shown in the middle of a frame (6), the rotor shaft (4) connects the rotor to the stator through a bearing (3, usually a ball bearing), and the force on the rotor can be transmitted to a stator body through the bearing. The structural part of the motor further comprises an upper end cover, a lower end cover and a shell, and the motor stator body is fixed on the base of the unmanned aerial vehicle.

The invention discloses a Chinese patent CN 102122872B, a wind driven generator with an axial magnetic suspension bearing, and provides a wind driven generator capable of generating axial magnetic suspension force by using a inherent magnetic field structure of a motor. However, in the field of wind power generators, both horizontal axis wind power generators and vertical axis wind power generators are subjected to two external forces, namely, the total gravity and wind thrust of a rotor body including turbine blades and a rotating shaft, and if one of the external forces is an axial external force, the other external force is a radial external force. In a horizontal axis wind turbine, gravity is a radial force and wind thrust is an axial force, while in a vertical axis wind turbine, wind thrust is a radial force and gravity is an axial force. The magnetic suspension wind motor can be offset by magnetic suspension force only through axial external force, so that the magnetic suspension in the invention is only a semi-magnetic suspension structure.

However, in the field of drones, and in particular in the field of multi-rotor drones used in large numbers, such as quad-rotor drones or hexa-rotor drones, the external force to which the drive motor is subjected, whether it is the gravity of the rotor and the rotor body of the motor shaft, or the lift force, which is basically an axial force, falls within the range in which the axial magnetic levitation force acts. Therefore, the invention improved by the invention transformed by the invention patent becomes a full magnetic suspension motor structure in the field of multi-rotor unmanned aerial vehicles, can eliminate friction force generated by gravity and lift force, and has better magnetic suspension performance and higher practical value.

Many rotor unmanned aerial vehicle's driving motor evenly arranges each symmetrical arm at unmanned aerial vehicle, use four rotor unmanned aerial vehicle as an example, 4 driving motor's pedestal mounting is on the symmetry four corners of unmanned aerial vehicle arm, install propeller blade on the motor shaft, the turn to of adjacent motor is opposite, propeller blade's inclination is also opposite, after these motors pass through airborne power supply rotation, all produce decurrent air current when making these paddles rotate, their lift is the same and superpose each other and form unmanned aerial vehicle's total lift, but the counter torque that they are rotatory to organism produced then mutual balance offsets. So the number of rotors or shafts of the unmanned aerial vehicle must be even.

Fig. 4 is a force diagram of one drive motor of the multi-rotor drone of the present invention.

In the figure, when the motor is not electrified, because the rotating shaft of the motor can freely lift along the axial direction, the gravity G of the shaft and the paddle acts on the shaft, and the rotating shaft can sink for a certain distance under the action of the gravity on the rotating shaft. The descending of the rotating shaft changes the magnetic force lines between the stator and the rotor from the horizontal direction to a downward oblique line, and the length of the oblique line is larger than that of a horizontal straight line. The nature of the magnetic field lines tends to shorten the length of the magnetic field lines, so that all the radial oblique lines generate an axial resultant force, which is an axial magnetic levitation force. Since the magnetic levitation force is generated by the gravity on the rotating shaft, the magnetic levitation force must be equal in magnitude and opposite in direction to the gravity on the rotating shaft. Therefore, as can be understood from the physical concept, the external force in the axial direction causes the rotor to freely move in the axial direction according to the magnitude and the direction of the external force, so that the rotor deviates from the balance position, and the moved rotor generates a magnetic levitation force which is equal to the external force in magnitude and opposite to the external force in direction. In a certain external force range, the larger the external force is, the longer the moving distance of the rotor is, and the larger the magnetic levitation force for restoring the rotor to the balance position is, so that the magnetic levitation force is always opposite to the external force in direction and equal in magnitude, and keeps the relationship of random balance with the external force.

When the motor is electrified, the unmanned aerial vehicle is lifted off, and new changes can be generated under the stress condition.

Fig. 5 is a diagram illustrating the rotation of the magnetic levitation motor of the present invention. When the motor in the figure is electrified, the motor drives the rotor wing to start rotating, the rotating speed is gradually increased, the downward stress of the bearing is also gradually reduced, and the rotating shaft is also gradually increased. Quickly, the lifting force is equal to the gravity on the rotating shaft, the motor shaft returns to the balance position of the magnetic force line of the rotor, the bearing stress is zero, and the stator and the rotor return to the position equivalent to that shown in fig. 3 at the moment.

But at the moment, the motor continues to accelerate and is acted by the lifting force, the rotating shaft also moves upwards continuously, and the bearing begins to be acted by the upward lifting force. Along with the continuous rising of the rotating speed, the bearing lifting force is increased along with the rising until the bearing lifting force L is reached. The unmanned aerial vehicle begins to lift off, except that receiving the gravity G of pivot and paddle on the motor shaft, has increased the air that the paddle fanned down and has aroused again and to the counter force L of paddle, and this counter force is exactly the lift after unmanned aerial vehicle lifts off. Taking a quad-rotor drone as an example, the lift L of each motor should be 1/4 of the total weight of the drone, and obviously, the lift L should be much larger than the motor shaft weight G.

Because the rotating shaft of the motor can freely move in the axial direction, the rotating shaft moves upwards under the action of the total resultant force, and the condition that the rotating shaft moves downwards when the motor is not powered on is changed. Therefore, the total force on the rotating shaft is upward, and the ascending distance of the rotating shaft of the motor is maximum.

At this moment unmanned aerial vehicle atress situation can be understood as the rotatory produced lift of back of paddle, is through axial magnetic levitation power, by the direct stator that transmits of rotor, then transmits the unmanned aerial vehicle organism through the stator base, and when driving motor's total lift equaled unmanned aerial vehicle weight, unmanned aerial vehicle just can stop aloft.

In a traditional unmanned aerial vehicle driving motor with a non-magnetic suspension structure, a motor bearing must adopt a bearing with thrust property, and an upper bearing and a lower bearing enable a rotating shaft to move downwards and upwards. So unmanned aerial vehicle rises to the air the back, and the lift of rotor can only be transmitted stator and unmanned aerial vehicle organism through the effect of bearing by the pivot, must produce frictional force and frictional loss in these bearings so.

In the bearing capable of freely moving in the axial direction, the magnetic force can not generate any thrust to the bearing any more, the lifting force can not be transferred through the bearing, and the friction force and the friction loss in the bearing are eliminated, so that the mechanical efficiency of the magnetic suspension motor is higher than that of a non-magnetic suspension motor, the energy utilization efficiency is highest, and the unmanned aerial vehicle can have more dead time or working time under the same airborne battery capacity. Simultaneously, owing to eliminated the frictional force of bearing, the produced heat of friction loss in the bearing greatly reduces, and the heat dissipation problem of bearing has actually been solved to a great extent, and the bearing variety that selects to be used for unmanned aerial vehicle is more. Because the abrasion caused by friction is reduced, the motor failure rate and the maintenance cost are reduced, and the service life of the bearing is prolonged.

The magnetic levitation force generated by the motor capable of freely moving in the axial direction changes along with the change of the external force, and reaches random balance anytime and anywhere, so that the rotating speeds of different motors can change in the maneuvering process of the unmanned aerial vehicle, such as advancing and retreating or steering, but the magnetic levitation force of each magnetic levitation motor can be correspondingly adjusted automatically according to the different external forces of each motor without an additional controller.

Even if the airborne weight of the unmanned aerial vehicle changes, as long as the shared lift force does not exceed the range of the maximum magnetic levitation force which can be maintained by the driving motor, the device can output the magnetic levitation force which meets the load change, namely the requirement of the lift force change. For example, in the experiment of the 5007-320kv motor, the possible lift force generated by the motor is between 0 and 4kg when the motor is in operation, but the maximum maglev force which can be provided by the motor is measured to be about 6 kg.

That is to say, the produced magnetic levitation force of driving motor can adapt to the change of unmanned aerial vehicle load, and this has just created the advantage for transporting the driven magnetic levitation of non-fixed load express delivery unmanned aerial vehicle of goods and materials.

Next, it is necessary to provide a specific structure of the two-degree-of-freedom bearing required by the present invention, that is, a specific bearing structure that can provide both rotational freedom and axial movement freedom.

The motor bearing is characterized in that two-degree-of-freedom bearings adopted at two ends of a motor rotating shaft are sliding bearings, and the sliding bearings are oil bearings or graphite-containing alloy bearings; when the rotating shaft is made of hard wear-resistant materials, the shaft sleeve is made of soft materials, so that bearing wear is limited to the shaft sleeve only. The shaft sleeve is also called as a bearing bush, is widely adopted in a large heavy-duty shaft system, and can be manufactured into two structures with semicircular shapes for convenient maintenance and replacement.

In fact, the shaft hole on motor shaft and the motor end cover also can be regarded as a pair of natural bearing that can provide the axial slip degree of freedom, but the motor rotates the in-process, always has wearing and tearing, so this natural bearing's life-span is not long, if inlay a axle sleeve in the shaft hole of motor end cover, the pivot adopts hard material and the axle sleeve adopts soft materials, so wearing and tearing mainly take place on the axle sleeve, when the axle sleeve wearing and tearing reach certain degree after, it is very convenient, the cost is also very little to change the axle sleeve new.

Of course, the shaft sleeve bearing is provided with sliding friction, while the traditional bearing is provided with a ball bearing in a large amount and is provided with rolling friction, and the sliding friction force is far greater than the rolling friction force, so that whether the cheap and good shaft sleeve is sufficient or not can be worried about.

However, it must be recognized that during the operation of the dynamically balanced rotor, the radial force applied to the motor bearing of the drone is zero when the drone is not affected by crosswind, and the precondition for the friction is a positive pressure on the moving surface perpendicular to the direction of motion. Since the bearing radial forces (positive pressures) during ideal operation are zero, the friction in the sliding bearing according to the invention should also be comparatively low, and a sliding sleeve bearing is still possible.

The invention also discloses another motor bearing which is characterized in that bearings at two ends of a motor shaft are multi-row ball bearings.

The traditional ball bearing only has one row of balls, and the balls in the row are distributed on the same axial circumference, so the axial length is shorter. The multi-row ball bearings are provided with balls on a plurality of axial circumferences, the axial length of the multi-row ball bearings is long, the sufficient axial sliding freedom degree of the rotating shaft can be provided, and the multi-row ball bearings can be produced as standard parts and can be directly adopted by selecting required specifications.

Another type of drone motor bearing of the invention is a rolling bearing, including ball bearings and roller bearings, but with the inner or outer ring of the bearing not being circular, i.e. the inner side of the inner ring or the outer side of the outer ring not being circular. Of course the outer side of the inner ring of the bearing and the inner side of the outer ring must still remain circular in order to ensure rotational freedom of the bearing. It is apparent that the purpose of this change is to separate the rotational function from the axial sliding function of the bearing without causing the rotational function and the axial sliding function to interfere with each other. The bearing is characterized in that the bearing is a rolling bearing; the outer side of the bearing inner ring and the inner side of the outer ring are required to be circular so as to form a rotational degree of freedom together with the rolling bodies; the inner side of the bearing inner ring or the outer side of the outer ring is of a non-circular structure so as to form a sliding degree of freedom with the rotating shaft or the motor end cover.

Fig. 6 is a schematic diagram of a special two-degree-of-freedom bearing which can be self-made by the invention. In the figure, the outer surface of the bearing inner ring (31) is provided with balls (32), and the inner side and the outer side of the inner ring are circular, which are the same as those of the conventional ball bearing. The outer end of the ball is a bearing outer ring (33), the inner side of the bearing outer ring is circular, and the bearing is a ball bearing with a special outer ring; the inner side and the outer side of the inner ring of the bearing are circular; the inner side of the outer ring of the bearing is circular, the outer side of the outer ring of the bearing is non-circular (shape which is not easy to rotate), the non-circular bearing is adopted to ensure that the middle of the bearing obtains the rotation freedom degree of the rotating shaft through balls, and the axial movement freedom degree of the rotating shaft is provided by the outer side of the bearing and a slide way of an end cover.

Such a bearing is basically the same as a conventional bearing in terms of manufacturing method, except for the difference in the outer side of the bearing outer ring.

The outer side of the outer ring of the special two-degree-of-freedom bearing is non-circular and is one of rectangular, oblong and elliptical geometric bodies or a composite outer ring geometric body with protruding strips and concave grooves.

FIG. 7 is a schematic view of a two-degree-of-freedom bearing with a recessed groove outer ring.

The motor end cover opening matched with the special two-degree-of-freedom bearing is matched with the outer side shape of the bearing, and the requirement of free axial movement of the rotating shaft can be met. However, since the axial movement is not frequent and is far less long than the working time for the bearing to rotate, the wear of the axial sliding is extremely limited and does not constitute a problem.

FIG. 8 is a schematic view of a two degree-of-freedom bearing with a convex inner ring. The two-degree-of-freedom bearing is matched with a rotating shaft, namely, the rotating shaft is required to be provided with a long groove matched with a convex body on an inner ring of the bearing.

In the permanent magnet motor of the invention, two types of motors can be selected, one type is a common alternating current permanent magnet synchronous motor and is regulated by an electronic frequency converter, the other type is a direct current permanent magnet brushless motor and is regulated by an electronic speed regulator, and the latter type is more commonly adopted.

In the alternating current synchronous motor, when the rotor magnet aligns with the magnetic conduction teeth on the electronic magnet yoke, the starting resistance of the motor is very large due to the influence of the cogging, so that the influence of the cogging can be reduced by two structures, the motor is easy to start, the stator slot can be changed into a chute, namely, the magnetic circuit tooth slot of the stator of the motor is arranged by staggering half teeth in the axial direction, the angle range of the magnetic force line of the rotor magnet entering and exiting the tooth slot of the stator magnet yoke is enlarged, the rotor is relatively easy to start, and the adverse effect of the cogging can be eliminated.

In the brushless dc motor, the number of slots of the stator yoke of the motor and the number of magnets on the rotor may be different from each other by even numbers. For example, the number of the designed magnetic circuit tooth grooves of the stator for the unmanned aerial vehicle driving motor 5007-320kv is 12, the number of the magnets on the rotor matched with the stator is 14, and the magnets are adhered to the surface of the rotor corresponding to the stator according to the interval polarity of N-S-N-S-N-S-N-S-N-S-N-S.

In conclusion, the magnetic suspension driving motor for the unmanned aerial vehicle can use various two-degree-of-freedom bearings including sliding bearings and rolling bearings, or can adapt to variable loads of the unmanned aerial vehicle by adopting the structure and the method of the traditional ball bearing most simply, and can reduce or eliminate the friction force in the motor bearing and improve the driving efficiency of the motor. And the mechanical loss of the motor is reduced, the abrasion is reduced, and meanwhile, the manufacturing cost of the motor is rarely or even not increased, so that a corresponding technical value is created for the magnetic suspension process of the unmanned aerial vehicle driving motor, and compared with all other existing magnetic suspension structures, the high cost factor of the traditional magnetic suspension structure is eliminated.

Claims (8)

1. The utility model provides a many rotor unmanned aerial vehicle's magnetic suspension driving motor device, the motor is by the stator, the rotor, the traditional radial magnetic field structure that bearing etc. constitutes, it has armature winding to inlay in the stator magnetic circuit lamination tooth's socket, rotor surface mounting has the magnet that becomes the dual, the magnetic pole opposite polarity of adjacent magnet is arranged, magnetic line of force flows through the stator yoke from a magnetic pole according to the motor is radial, get back to the other two opposite polarity magnetic poles on rotor both sides from other radial directions, then accomplish the magnetic line of force return circuit through the rotor yoke, characterized by, the motor bearing adopts the two degree of freedom bearings of rotation and axial displacement, two degrees of freedom are according to the rotatory degree of freedom of rotor shaft and the degree of freedom along rotor axial displacement promptly, make the rotor produce, be in epaxial lift and cross the motor bearing, directly transfer to on the stator.

2. The magnetic suspension driving motor device for unmanned aerial vehicle of claim 1, wherein the two-degree-of-freedom bearings used at both ends of the motor shaft are sliding bearings, and the sliding bearings are oil-containing bearings or graphite-containing alloy bearings; when the rotating shaft is made of hard wear-resistant materials, the shaft sleeve is made of soft materials.

3. The magnetic levitation drive motor apparatus for unmanned aerial vehicles as claimed in claim 1, wherein the two-degree-of-freedom bearings used at both ends of the motor shaft are multi-row ball bearings having balls on several axial circumferences.

4. The magnetic suspension driving motor device for unmanned aerial vehicle of claim 1, wherein the two-degree-of-freedom bearings used at both ends of the motor shaft are special shaped ball bearings; the outer side of the bearing inner ring and the inner side of the outer ring are required to be circular so as to form a rotational degree of freedom together with the rolling body; the inner side of the bearing inner ring or the outer side of the outer ring is of a non-circular structure so as to form a sliding degree of freedom with the rotating shaft or the motor end cover.

5. An unmanned aerial vehicle magnetic suspension drive motor device as claimed in claim 1 or claim 4, wherein the outer side of the bearing outer ring is rectangular, oblong, oval or a composite outer ring geometry with protruding bars or recessed grooves; or the inner side of the bearing inner ring is a composite outer ring geometric body with protruding strips so as to form the freedom degree of axial movement by matching with the rotating shaft or the motor end cover.

6. The unmanned aerial vehicle magnetic suspension driving motor device of claim 1, characterized in that the motor stator magnet yoke tooth grooves are arranged in a skewed slot structure, that is, the motor stator magnet yoke tooth grooves are arranged with a staggered half tooth position, so as to reduce the tooth groove effect of the permanent magnet motor.

7. The magnetic suspension driving motor device for unmanned aerial vehicle of claim 1, characterized in that the number of the slots of the magnetic yoke of the stator of the motor and the number of the magnets on the rotor are different even numbers so as to reduce the slot effect of the permanent magnet motor.

8. The magnetic levitation drive motor device for unmanned aerial vehicles as claimed in claim 1, wherein the motor structure is a dc brushless motor or an ac permanent magnet synchronous motor.

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