Lightweight high-efficiency motor of unmanned aerial vehicle

Abstract

The invention discloses a light-weight efficient motor of an unmanned aerial vehicle, which comprises a motor shell, and the motor shell is connected with a rotating shaft through a bearing; the stator assembly is fixed in the motor shell, the stator assembly is composed of single stator assemblies which are circumferentially distributed by taking a rotating shaft as an axis, each single stator assembly comprises a single stator iron core and an electric drive winding which winds the single stator iron core, and the single stator iron core is made of an amorphous material or an amorphous nanocrystalline biphase material; and the front rotor assembly and the rear rotor assembly are fixedly arranged on the rotating shaft in a sleeving mode, located at the two ends of the stator assembly at the same time and used for driving the rotating shaft to rotate. The light-weight high-efficiency motor of the unmanned aerial vehicle is light in weight, high in frequency and low in loss.

Description

Technical Field

[0001] The invention belongs to the technical field of unmanned aerial vehicle motors, and in particular relates to a lightweight and efficient motor for unmanned aerial vehicles. Background Art

[0002] UAVs are widely used in agricultural farming, environmental protection, aerial photography and mapping, battlefield reconnaissance, battlefield attack and other fields; the electric propulsion system load requires miniaturization and lightweight, and the motor is the core component of the development of electric UAV and electric aircraft technology. High efficiency, high speed, miniaturization and lightweight of motors are the main technical trends of UAV motors in the future. High frequency of motors can bring the advantages of high speed and high power density. However, the existing motor structure generally uses silicon steel sheets as stator cores. Due to the high unit iron loss of silicon steel sheet materials, when the motor works at high frequency and high speed, the stator core loss is high, causing the overall temperature rise of the motor to be too high, affecting the motor efficiency and power density. In addition, when the overall heat of the motor is serious, the permanent magnet rotor material is very prone to thermal demagnetization, affecting the stability and reliability of the motor.

[0003] Dorsa Talebi and other researchers from Texas A&M University reported in the IEEE Transactions on Industry Applications journal that an axial flux motor with a rated power of 83kW for electric drones or electric aircraft is titled "Electromagnetic Design Characterization of a Dual Rotor Axial Flux Motor for Electric Aircraft". The motor adopts a yokeless dual rotor magnetic circuit design, the motor mass is less than 8kg, and the efficiency is 94.36%. However, the motor described in the report uses a silicon steel stator core wound with flat wire armature windings. When working at a rated frequency of 1333Hz, the stator core loss is as high as 1.32kW, and the armature winding loss is 2.59kW.

[0004] The invention patent with application publication number CN117791982A discloses a method for preparing an amorphous nanocrystalline stator core in the field of high-speed motors and an amorphous nanocrystalline motor. The method first cuts an amorphous or nanocrystalline strip and then stacks it into an alloy block, which is then heat treated after being clamped and fixed, and then cut and processed into an amorphous or nanocrystalline stator core after being dipped and cured. However, the amorphous or nanocrystalline strip described in the patent is relatively thick, and it is difficult to achieve higher working efficiency of the motor at a higher speed.

[0005] The invention patent with application publication number CN114244037B discloses a method for preparing an amorphous alloy motor core and a motor. The method makes an amorphous alloy strip into a semi-finished core, and performs paint-impregnated curing wire cutting on the semi-finished core to obtain an amorphous alloy core. The method reduces the annealing step of the amorphous alloy core and equips the motor with an operating frequency of 200-3000Hz. Compared with the annealed amorphous core, the loss advantage is not great, and it is difficult to achieve higher working efficiency under wide frequency.

[0006] The stator core slot of the dual-rotor axial flux motor without yoke is simple and easy to process. Amorphous alloy strip is a thin strip material with constant width and length, which is easy to wind and form. Therefore, amorphous alloy strip has advantages in the application of axial flux motor stator core.

[0007] In summary, in order to meet the requirements of high efficiency, high power density, lightweight and miniaturization of UAV motors, it is urgent to develop a lightweight, high-frequency, low-loss amorphous high-efficiency motor. Summary of the invention

[0008] The present invention provides a lightweight, high-frequency and low-loss lightweight and high-efficiency motor for an unmanned aerial vehicle.

[0009] A specific embodiment of the present invention provides a lightweight and efficient motor for a drone, comprising:

[0010] A motor housing, wherein the electrode housing is connected to the rotating shaft through a bearing;

[0011] A stator assembly, wherein the stator assembly is fixed inside the motor housing, and the stator assembly is composed of a single stator assembly distributed circumferentially with the rotating shaft as the axis, and the single stator assembly includes a single stator core and an electric drive winding wound around the single stator core, and the single stator core is made of amorphous material or amorphous nanocrystalline dual-phase material;

[0012] The front rotor assembly and the rear rotor assembly are respectively fixedly sleeved on the rotating shaft and are located at both ends of the stator assembly for driving the rotating shaft to rotate.

[0013] Preferably, the front rotor assembly and the rear rotor assembly respectively independently include NS pole permanent magnets with an axial magnetization direction and Halbach magnets with a circumferential magnetization direction, the NS pole permanent magnets are close to the stator assembly, and the Halbach magnets are far away from the stator assembly.

[0014] The present invention adopts a stator made of high-frequency, low-loss amorphous single-phase or nanocrystalline-amorphous dual-phase material, and a dual-rotor permanent magnet whose cooperative magnetization direction is a combination of a circumferential direction and an axial NS direction. Through the armature reaction between a single stator core and the permanent magnet provided by the present invention, the uniformity of the core magnetic flux distribution is improved, the air gap magnetic flux density is increased, and the leakage magnetic flux is reduced, thereby weakening the cogging torque, increasing the output power and making the weight lighter, and ultimately achieving high power density and high efficiency of the motor.

[0015] Preferably, the front rotor assembly and the rear rotor assembly each independently include NS-pole permanent magnets with magnetization directions in the axial direction and a rotor core, the NS-pole permanent magnets are close to the stator assembly, and the rotor core is far away from the stator assembly. Replacing the Halbach magnet with the rotor core reduces the difficulty of the production process, reduces the amount of permanent magnets, reduces leakage flux, and increases the motor output.

[0016] Preferably, the NS-pole permanent magnets and the single stator assembly are arranged according to an axial magnetic circuit, and the distance between the single stator assembly and the NS-pole permanent magnets is 0.6-1.2 mm.

[0017] Preferably, the number of poles is 24-42, the number of the single stator components is 24-42, and the number of poles provided in the specific embodiment of the present invention is the number of poles of NS pole permanent magnets.

[0018] Preferably, the thickness of the NS-pole permanent magnet is 4-10 mm, the NS-pole permanent magnet is divided into 5-10 segments in radial direction, and the pole arc coefficient of the NS-pole permanent magnet is 0.5-0.9.

[0019] Preferably, the axial height of the single stator core is 30-48 mm;

[0020] A straight slot is provided between the single stator cores, the electric drive winding is located in the straight slot, the width of the straight slot is 6-14 mm, and the distance between the end of the single stator core and the end of the electric drive winding is 0-10 mm.

[0021] Under the condition that the amount of permanent magnets and copper used remains unchanged, the higher the axial height of the single stator core, the greater the core mass, the higher the iron loss, the greater the distance between the end of the single stator core and the end of the electric drive winding, the smaller the alternating magnetic field in the winding, and the lower the AC copper loss. The present invention achieves high efficiency and high power density of the motor by controlling the axial height of the single stator core and the distance between the end of the single stator core and the end of the electric drive winding.

[0022] Preferably, the single stator core is made by winding, pressing, annealing, varnishing, curing and wire cutting amorphous or amorphous nanocrystalline strips.

[0023] Preferably, the predetermined annular part is obtained by winding amorphous or amorphous nanocrystalline strips, the inner diameter of the predetermined annular part is 40-60 mm, and the outer diameter of the predetermined annular part is 70-80 mm. The required lamination thickness and axial height of the single stator core can be achieved by adjusting the inner and outer diameters of the predetermined annular part.

[0024] Preferably, the electric drive winding is obtained by winding multiple wires in parallel, the number of turns is 9-12 turns, the wire diameter of a single winding is 0.5-1 mm, and the number of windings is 8-48.

[0025] Preferably, the motor power density of the lightweight and high-efficiency motor of the drone is not less than 10.9 kW / kg, the rated speed of the motor exceeds 8000 rpm, the motor efficiency is not less than 97%, and the motor mass is not higher than 7.75 kg.

[0026] Preferably, the motor power density of the lightweight and high-efficiency motor of the UAV is 11.55 kW / kg, the motor efficiency is 97.9%, and the motor mass is not higher than 7.33 kg.

[0027] The technology of the present invention designs the optimal working point of the magnetic flux density of the amorphous or nanocrystalline-amorphous flexible sheet stator core through the design of the size of the high-frequency and low-loss amorphous or nanocrystalline-amorphous flexible sheet stator core, the design of the rotor permanent magnet excitation magnetic field, the design of the armature winding current density and the parallel winding of multiple strands of armature round wire windings, and gives full play to the advantages of extremely low core loss and low AC copper loss of amorphous or nanocrystalline-amorphous materials in high-frequency applications of drone motors, thereby reducing the motor loss under high frequency, effectively reducing the mass of the drone motor, and at the same time improving the motor efficiency and power density.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention uses amorphous or nanocrystalline-amorphous strips to make a motor stator core with high saturation magnetic induction, high lamination coefficient and low core loss. The motor efficiency is 2% higher than that of an ordinary silicon steel core motor at an application frequency of more than 1000 Hz. The single stator component made of amorphous or amorphous nanocrystalline two-phase material is arranged circumferentially. Due to the unique yokeless structure of the circumferentially arranged stator core, it has the advantages of easy block processing, small axial size, short magnetic circuit and strong output capacity.

[0030] The lightweight amorphous high-efficiency motor provided by the present invention adopts high-frequency and low-loss amorphous or nanocrystalline-amorphous sheets as the stator core, combines the yokeless structural design, and coordinates the magnetic circuit design of the axial flux direction of the dual rotors, so as to achieve a power density of the high-efficiency motor of not less than 10.9kW / kg, a rated speed of 8000rpm, a motor efficiency of not less than 97%, and a motor effective material mass of not more than 7.75kg, which is better than the performance of existing drone motors and has broad application prospects in drone motor applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a ring-shaped part before being pressed by winding an amorphous alloy strip having a certain width around a steel plate mold having predetermined inner and outer diameters provided in a specific embodiment of the present invention;

[0032] Figure 2 A schematic diagram of an alloy block after being pressed by a steel plate mold for a ring member provided in a specific embodiment of the present invention;

[0033] Figure 3 Schematic diagram of a single stator core provided for Comparative Example 1-Comparative Example 2 and Example 1-Example 8, wherein Figure 3 (a) is a schematic diagram of a single stator core provided in Comparative Example 1, Figure 3 (b) is a schematic diagram of a single stator core provided for Comparative Example 2 and Examples 1 to 8;

[0034] Figure 4 This is a topological explosion diagram of the lightweight and efficient motor for a drone prepared in Example 1-8, wherein Figure 4 (a) is a topological explosion diagram of the lightweight and efficient motor of the UAV prepared in Examples 1-6, Figure 4 (b) is a topological explosion diagram of the lightweight and efficient motor for UAV prepared in Example 7-8;

[0035] Figure 5 A schematic diagram of an amorphous stator core support component of an amorphous axial flux motor provided in a specific embodiment of the present invention.

[0036] The reference numerals are as follows:

[0037] 1. Steel plate pressing die;

[0038] 2. Pre-order ring parts;

[0039] 3. Single stator core;

[0040] 4. Electric drive winding;

[0041] 5. Straight groove;

[0042] 6. Rotor permanent magnet;

[0043] 7. Rotor core;

[0044] 8. Stator fixing bracket structure;

[0045] 9. Fixing bolt holes;

[0046] 10. Motor housing;

[0047] 11. Fix the inner shell;

[0048] R1 is the inner radius of the predetermined annular part before the steel mold is pressed; R2 is the outer radius of the predetermined annular part before the steel mold is pressed; Do is the outer diameter of the motor; Di is the inner diameter of the motor; Th_R is the axial length of the rotor core; Th_PM is the axial height of the rotor permanent magnet; Th_S is the thickness of the amorphous core in the stacking direction, that is, the thickness of the single stator core; Hs0 is the distance between the end of the single stator core of the stator and the end of the electric drive winding; Hs1 is the axial height of the single stator core; Bs0 is the slot width of the straight slot. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings and examples. The specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. For ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] In the prior art, the process of preparing the stator core using amorphous or nanocrystalline-amorphous dual-phase materials is to preliminarily cut the amorphous alloy strip into predetermined laminations, laminate them one by one to the thickness of the stator core, and then anneal, dip paint and solidify them before cutting. Because the amorphous alloy strip has extremely high hardness, the method of cutting the amorphous alloy strip into predetermined laminations one by one and then laminating them to the thickness of the stator core will take up a lot of working time, and the process of cutting the laminations one by one will cause differences in the magnetic properties of each lamination material.

[0051] In view of this, the specific embodiment of the present invention considers combining the winding and laminating processes to provide a method for manufacturing an amorphous or nanocrystalline-amorphous dual-structure stator core by flattening and fixing the annular member using a fixed steel mold after the amorphous alloy strip is wound into an annular member with a predetermined inner and outer diameter, and then performing annealing, varnishing and curing operations together with the fixed steel mold, and finally cutting and processing. The manufacturing method of the amorphous or nanocrystalline-amorphous dual-structure stator core will be described in detail below, as follows:

[0052] The step of winding the ring part, according to the size of the finished stator core and the direction of the lamination, one or more amorphous alloy strips are wound to form a ring part, and the tension of the amorphous alloy strip during winding is increased to achieve a higher core lamination factor, and the lamination factor is increased to above 0.9. The height of the wound ring part is the width of the amorphous alloy strip. The size of the ring part is calculated according to the size of the finished core. The radial direction, circumferential direction and height direction of the ring part are the lamination direction, axial length direction and width direction of each lamination of the finished stator core, respectively. The difference between the inner and outer diameters of the ring part is the thickness of the finished stator core lamination, and the inner diameter is the axial length of the finished core.

[0053] Fixed processing steps, see Figure 1Two steel plate pressing dies 1 with bolts are arranged on both sides of the predetermined annular member 2 in the radial direction, and the bolts connecting the steel plates are tightened to press the annular member to obtain Figure 2 The alloy block shown. The pressed steel plate mold needs to have high hardness, certain quality and high temperature resistance of 500℃. Reasonable steel plate size ensures that the mold and alloy block are placed in the annealing furnace for the next step. The single steel plate pressing mold is 100mm wide, 200mm long and 14mm thick, with 4 screw holes, 8mm screw hole diameter, 15mm steel plate edge at the center of the screw hole, and a total screw length of 100mm.

[0054] Annealing steps, see Figure 2 The alloy block shown, together with the pressed steel plate mold, is placed in a vacuum annealing furnace for annealing and stress relief treatment to obtain an amorphous or nanocrystalline-amorphous dual-structure stator core with excellent soft magnetic properties.

[0055] In the annealing step, the annealing furnace cavity has a width of 150 mm, a height of 120 mm and a furnace depth of 300 mm. The annealing process is carried out under a nitrogen protective atmosphere, and the temperature is raised to 370° C. at a heating rate of 5° C. / min, and each alloy block including the fixed steel plate mold is kept warm for 1 hour.

[0056] In the varnishing and curing step, the annealed alloy block and the pressed steel plate mold are placed in a vacuum varnishing furnace, and the curing temperature is controlled at 100°C. The curing time is directly related to the lamination size of the core to ensure that the adhesive in the core is completely cured.

[0057] Cutting step: wire cutting is used to obtain the solidified alloy block. Figure 3 (b) shows the finished amorphous or nanocrystalline-amorphous dual-phase single stator core 3.

[0058] See also Figure 4 (a) and 4(b) show the dual-rotor axial flux amorphous high-efficiency motor model. Each amorphous or nanocrystalline-amorphous dual-phase structure stator core 3 prepared is evenly distributed along the circumference of the motor to form a stator assembly. The electric drive winding 4 is wound around each single stator core 3 through a straight slot 5 shown by the slot width Bs0. The core and the winding are fixed by fixing bolts through a stator fixing bracket structure 8 steel bracket. The fixing bolts pass through the fixing bolt holes 9 and are fixedly connected to the outer casing 10 and the inner casing 11 through the stator fixing bracket structure 8. Finally, epoxy resin is filled to fix the entire stator structure, as shown in FIG. Figure 4 As shown in (a), the front rotor assembly and the rear rotor assembly each independently include an NS-pole permanent magnet 6 with an axial magnetization direction and a Halbach magnet with a circumferential magnetization direction, the NS-pole permanent magnet 6 is close to the single stator core 3, and the Halbach magnet is far away from the single stator core 3, as shown in FIG. Figure 4As shown in (b), the front rotor assembly and the rear rotor assembly each independently include an NS-pole permanent magnet 6 and a rotor core 7 whose magnetization direction is the axial direction. The NS-pole permanent magnet 6 is close to the stator assembly, and the rotor core 7 is far away from the stator assembly. The front rotor assembly and the rear rotor assembly are both fixed on the rotating shaft and encapsulated inside the motor housing to drive the rotating shaft to rotate. The rotating shaft is connected to the motor housing bearing, and the motor housing remains stationary when the rotating shaft rotates through the bearing connection.

[0059] The "I" type steel bracket support structure of the stator part of the dual rotor axial flux amorphous high-efficiency motor is as follows Figure 5 As shown, it mainly plays the role of supporting and fixing the stator, wherein each steel bracket is located between two adjacent winding layers in each stator slot, and each steel bracket is connected to the casing.

[0060] Example 1

[0061] In this embodiment, the method of manufacturing the stator core using the method described in the present invention is the same as the method of manufacturing the amorphous nanocrystalline alloy stator core for the dual-rotor axial magnetic field motor. Taking the preparation of the amorphous alloy stator core as an example, the amorphous alloy strip with a nominal composition of Fe 81.4 Si 6.8 B 8.6 Cu 0.7 P 1.9 Nb 0.6 (at.%), the strip thickness is 18μm, and the width is 60mm. The alloy strip is subjected to winding pressing and reheat treatment: the inner radius R1 of the predetermined ring part before the steel mold pressing is 20mm, and the outer radius R2 of the predetermined ring part before the steel mold pressing is 32.5mm. The temperature is raised to 370℃ at a heating rate of 5℃ / min, and kept warm for 1h to obtain an annealed amorphous alloy block. The amorphous alloy block is placed in a vacuum impregnation furnace and soaked in epoxy resin for several hours, and kept warm at 100℃ for 2h to solidify. Finally, the solidified amorphous block is cut to obtain an amorphous stator core.

[0062] The dual rotor provided in this embodiment is composed only of NdFeB permanent magnets with different magnetizing directions. The rotor permanent magnets are composed of Halbach magnets with magnetizing directions in the circumferential direction and NS pole permanent magnets in the axial direction. The number of NS pole permanent magnets is the same as that of Halbach magnets, the pole arc coefficient is 0.5, and the thickness of the permanent magnet is 5 mm. The rotor permanent magnet with a radial block number of 10 is prepared by conventional methods. The permanent magnet material grade is N48SH. The stator and rotor are assembled by conventional methods to obtain a lightweight and efficient motor for an amorphous drone.

[0063] The main parameters of the motor in the embodiment 1 include: 40 poles, 42 single stator cores, an outer diameter Do of 250 mm, an inner diameter Di of 200 mm, an axial height Hs1 of a single stator core of 44 mm, a slot body width Bs0 of a straight slot between a single stator core of 8 mm, a slot width equal to a slot body width, a distance Hs0 between an end of a single stator core and an end of an electric drive winding of 4 mm, a round wire winding wire diameter of 0.5 mm, a winding turn number of 9 and a parallel winding number of 48, an axial height Th_PM of a NS-pole permanent magnet of 5 mm, and a thickness Th_S of a single stator core of 25 mm.

[0064] At a rated speed of 8000rpm and an excitation current of 75A, the motor output torque obtained in Example 1 reaches 101.13Nm, the efficiency reaches 97.91%, the motor mass is 7.33kg, the motor stator core loss is 150W, and the core loss accounts for 15.76%. The motor efficiency of this embodiment is more than 2% higher than that of Comparative Examples 1 and 2, and the mass is less than that of Comparative Examples 1 and 2, and the motor high efficiency and lightweight miniaturization are basically achieved.

[0065] Example 2

[0066] The difference between Example 2 and Example 1 is that the winding wire diameter used in Example 2 is 1 mm, and the number of windings is 12.

[0067] Under the same test conditions as Example 1, the motor efficiency of Example 2 is 97.22%, the output torque and mass are the same as those of Example 1, and the motor stator core loss is the same as that of Example 1, with a loss ratio of 9.66%. The motor performance of this example is better than that of Comparative Example 1 and Comparative Example 2, meeting the requirements of high efficiency and lightweight.

[0068] Example 3

[0069] The difference between Example 3 and Example 2 is that the distance between the end of the single stator core provided in Example 3 and the end of the electric drive winding is 7 mm, and the axial height of the single stator core is adjusted to 50 mm.

[0070] The motor provided in this embodiment has an efficiency of 97.35%, a mass of 7.75 kg, a stator core loss of 170 W, and a loss ratio of 11.88%. The motor mass is less than that of comparative examples 1 and 2, and the motor efficiency of embodiment 3 is higher than that of comparative examples 1 and 2, meeting the requirements of motor high efficiency and miniaturization.

[0071] Example 4

[0072] The difference between Example 4 and Example 2 is that the distance between the end of the single stator core of Example 4 and the end of the electric drive winding is 6 mm, and the axial length of the single stator core is 48 mm.

[0073] The motor efficiency provided by Example 4 is 97.33%, the mass is 7.61kg, the stator core loss is 164W, and the loss accounts for 11.32%. The electromagnetic performance of the motor in Example 4 is better than that of Comparative Example 1 and Comparative Example 2, meeting the requirements of motor high efficiency and miniaturization.

[0074] Example 5

[0075] The difference between Example 5 and Example 2 is that the distance between the end of the single stator core of Example 5 and the end of the electric drive winding is 5 mm, and the axial length of the single stator core is 46 mm.

[0076] The motor provided in Example 5 has an efficiency of 97.31%, a mass of 7.47 kg, a stator core loss of 156 W, and a loss ratio of 10.57%. The electromagnetic performance of the motor in Example 5 is better than that of Comparative Example 1 and Comparative Example 2, meeting the requirements of motor efficiency and miniaturization.

[0077] Example 6

[0078] The difference between Example 6 and Example 2 is that the distance between the end of the single stator core of Example 6 and the end of the electric drive winding is 3 mm, and the axial length of the single stator core is 42 mm.

[0079] The motor provided by Example 6 has an efficiency of 97.05%, a mass of 7.20 kg, a stator core loss of 143 W, and a loss ratio of 8.39%. The electromagnetic performance of the motor in Example 6 is better than that of Comparative Example 1 and Comparative Example 2, meeting the requirements of motor efficiency and miniaturization.

[0080] Example 7

[0081] The dual rotor provided in this embodiment, i.e., the front rotor assembly and the rear rotor assembly are independently composed of NS-pole NdFeB permanent magnets in the axial direction and a rotor core. The pole arc coefficient of the NS-pole magnet is 0.8, the thickness of the permanent magnet is 5 mm, and the dual rotor permanent magnet with a radial block number of 10 is prepared by conventional methods. The permanent magnet material is grade N48SH and has a residual magnetism of 1.1T.

[0082] The main parameters of the motor provided in Example 7 include: 26 poles, 27 single stator cores, 250 mm outer diameter, 200 mm inner diameter, 30 mm axial height of the single stator core, 12 mm slot width of the straight slot between the single stator cores, the slot width equal to the slot width, 3 mm distance between the end of the single stator core and the end of the electric drive winding, 0.5 mm round wire winding wire diameter, 12 winding turns and 32 parallel windings, 25 mm thickness Th_S of the single stator core, and 8 mm axial length Th_R of the rotor core.

[0083] The motor efficiency of Example 7 is 97.69%, the mass is 7.26 kg, the stator core loss is 87 W, and the loss accounts for 7.30%. The electromagnetic performance of the motor of Example 7 is better than that of Comparative Example 1 and Comparative Example 2, meeting the requirements of motor high efficiency and miniaturization.

[0084] Example 8

[0085] The difference between Example 8 and Example 7 is that the diameter of the round wire winding is 1 mm, and the number of windings is 8.

[0086] The motor mass and core loss of Example 8 are the same as those of Example 7, but the number of parallel windings is reduced, the DC resistance is increased, and the copper loss is increased. The winding copper loss is 1378W, which is higher than the copper loss of 791W in Example 7, and the motor efficiency is reduced to 97.05%. The number of parallel windings is too small, and the winding wire diameter is too large, resulting in excessive resistance, so the copper loss increases and the electrode efficiency decreases. However, the electromagnetic performance of the motor provided by Example 8 is better than that of Comparative Examples 1 and 2, meeting the requirements of motor efficiency and miniaturization.

[0087] Comparative Example 1

[0088] The solution of comparative example 1 adopts the design parameters of one of the UAV axial flux motors reported by American researchers such as Dorsa Talebi in the background technology. The structure of the stator core provided in comparative example 1 is as follows: Figure 3 (a) shown.

[0089] The main parameters of the motor in the comparative example 1 include: 40 poles, 42 single stator cores, rated speed 4000 rpm, outer diameter 270 mm, inner diameter 220 mm, axial height of single stator core 30 mm, stator core slot width 9 mm, slot width 6 mm, the distance between the end of the single stator core and the end of the electric drive winding is 1.4 mm, the winding adopts 1.8×3 mm flat wire, the number of winding turns is 12, the stator core material is 35JN250, and the thickness Th_S of the single stator core is 25 mm.

[0090] Comparative Example 2

[0091] The difference between the comparative example 2 and the embodiment 8 is that the number of the round wire windings is 12, the stator and rotor cores are both made of silicon steel 35JN250, and the axial height of the stator core is 42 mm.

[0092] The motor efficiency of the comparative example 2 is lower than that of the motors of the above-mentioned embodiments 1-8, the mass is higher than that of the above-mentioned embodiments 1-8, the power density is also lower than that of the embodiment, and the comprehensive performance is not as good as that of the motors of embodiments 1-8.

[0093] Table 1 is a comparison of the motor output torque, output power, motor efficiency, mass and power density of Examples 1-8 and Comparative Examples 1-2

[0094]

[0095]

Claims

1. A lightweight and efficient motor for a drone, characterized in that: include: A motor housing, wherein the electrode housing is connected to the rotating shaft through a bearing; A stator assembly, wherein the stator assembly is fixed inside the motor housing, and the stator assembly is composed of a single stator assembly distributed circumferentially with the rotating shaft as the axis, and the single stator assembly includes a single stator core and an electric drive winding wound around the single stator core, and the single stator core is made of amorphous material or amorphous nanocrystalline dual-phase material; The front rotor assembly and the rear rotor assembly are respectively fixedly sleeved on the rotating shaft and are located at both ends of the stator assembly for driving the rotating shaft to rotate.

2. The lightweight and efficient motor for drone according to claim 1, characterized in that: The front rotor assembly and the rear rotor assembly respectively independently include NS pole permanent magnets with an axial magnetization direction and Halbach magnets with a circumferential magnetization direction. The NS pole permanent magnets are close to the stator assembly, and the Halbach magnets are far away from the stator assembly.

3. The lightweight and efficient motor for drone according to claim 1, characterized in that: The front rotor assembly and the rear rotor assembly each independently include an NS-pole permanent magnet with an axial magnetization direction and a rotor core, the NS-pole permanent magnet is close to the stator assembly, and the rotor core is far away from the stator assembly.

4. The lightweight and efficient motor for unmanned aerial vehicles according to claim 2 or 3, characterized in that: The NS pole permanent magnets and the single stator assembly are arranged according to an axial magnetic circuit, and the distance between the single stator assembly and the NS pole permanent magnets is 0.6-1.2 mm.

5. The lightweight and efficient motor for drone according to claim 1, characterized in that: The number of poles is 24-42, and the number of single stator assemblies is 24-42.

6. The lightweight and efficient motor for drone according to claim 4, characterized in that: The thickness of the NS-pole permanent magnet is 4-10 mm, the NS-pole permanent magnet is divided into 5-10 segments in radial direction, and the pole arc coefficient of the NS-pole permanent magnet is 0.5-0.

8.

7. The lightweight and efficient motor for drone according to claim 1, characterized in that: The axial height of the single stator core is 30-48 mm; A straight slot is provided between the single stator cores, the electric drive winding is located in the straight slot, the width of the straight slot is 6-14 mm, and the distance between the end of the single stator core and the end of the electric drive winding is 0-10 mm.

8. The lightweight and efficient motor for drone according to claim 1, characterized in that: The single stator core is made by winding, pressing, annealing, varnishing and curing, and wire cutting amorphous or amorphous nanocrystalline strips.

9. The lightweight and efficient motor for drone according to claim 8, characterized in that: The amorphous or amorphous nanocrystalline ribbon is wound to obtain a predetermined annular member, wherein the inner diameter of the predetermined annular member is 40-60 mm, and the outer diameter of the predetermined annular member is 70-80 mm.

10. The lightweight and efficient motor for drone according to claim 1, characterized in that: The electric drive winding is obtained by winding multiple wires in parallel, the number of turns is 9-12 turns, the wire diameter of a single winding is 0.5-1mm, and the number of windings is 8-48.

11. The lightweight and efficient motor for drone according to claim 1, characterized in that: The motor power density of the lightweight and high-efficiency motor of the UAV is not less than 10.9 kW / kg, the rated speed of the motor is more than 8000 rpm, the motor efficiency is not less than 97%, and the motor mass is not higher than 7.75 kg.

12. The lightweight and efficient motor for drone according to claim 1, characterized in that: The motor power density of the lightweight and high-efficiency motor of the UAV is 11.55 kW / kg, the motor efficiency is 97.9%, and the motor mass is no more than 7.33 kg.

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