High-torque-density motor for electric aircraft

Abstract

The invention discloses a high-torque-density motor for an electric aircraft, which adopts a mode of radially inserting an inner rotor, 54 slots, 42 poles and four sections of rotor iron core skewed slot magnetic steel, and has the properties of symmetrical magnetomotive force waveform, high winding coefficient, low torque ripple and cogging torque and no end ring current. The motor adopts a centralized duplex winding and shell cooling fin air cooling mode, and has the characteristics of large torque, light weight, simple cooling mode and large safety margin. While higher torque density and power density are achieved, heating is stable and controllable, and the phenomenon of burnout is not prone to occurring.

Description

[Technical field]

[0001] The invention belongs to the technical field of motors, and in particular relates to a motor for electric aircraft with high torque density. [Background technology]

[0002] With the rapid development of the low-altitude economy, electric propulsion aircraft have increasingly higher requirements for the torque density and power density of propulsion motors. Compared with new energy vehicle motors, their power density generally does not exceed 3.5KW / Kg and their torque density does not exceed 8Nm / Kg. The current maximum torque density of motors required by electric aircraft has reached 50Nm / Kg, and the maximum power density has reached 8.5KW / Kg. However, the system is more complicated under the liquid cooling method of the motor. Once the liquid cooling system fails, the motor will burn out, leading to irreversible consequences.

[0003] Therefore, it is necessary to provide a new high torque density electric aircraft motor to solve the above technical problems. [Summary of the invention]

[0004] The main purpose of the present invention is to provide a motor for electric aircraft with high torque density, which can achieve higher torque density and power density while generating stable and controllable heat and is not prone to burning.

[0005] The present invention achieves the above-mentioned object through the following technical solutions: A motor for an electric aircraft with high torque density, comprising a stator and a rotor arranged inside the stator; the stator comprises a stator core and a winding, the inner wall of the stator core is provided with a plurality of stator slots at equal angles along its own circumference, and each of the stator slots is provided with the winding; the rotor comprises a rotor core and a magnetic steel group, the outer wall of the rotor core is provided with a plurality of accommodating cavities at equal angles along its own circumference, and each of the accommodating cavities is provided with a group of magnetic steel groups;

[0006] The number of the stator slots is 54, and the number of the magnetic steel groups is 42, forming a matching structure of 54 slots and 42 poles;

[0007] The winding adopts a centralized double winding form;

[0008] The stator core has an outer diameter D1 of 355 mm and an inner diameter D2 of 308.6 mm;

[0009] The outer diameter D3 of the rotor core is 306 mm, and the inner diameter D4 is 286 mm;

[0010] The air gap between the stator and the rotor is L1=1.3 mm;

[0011] The slot width L2 of the stator slot is 3.5 mm, the slot depth L3 is 18.7 mm, the slot tip angle θ1 is 28°, and the stator slot is a parallel slot with a parallel slot width L4 of 9.4 mm;

[0012] The rotor adopts four-stage tilted pole treatment, and the tilted pole treatment angles are: -0.5626°, -0.1875°, 0.1875°, and 0.5625° respectively.

[0013] Furthermore, a stator tooth is formed between two adjacent stator slots, and the air gap is formed between the inner wall of the stator tooth and the outer wall of the magnetic steel group.

[0014] Furthermore, the main cross-section of the stator slot is rectangular, and a retracted slot opening is formed on one side close to the inner wall of the stator core, and the retracted profile is a straight line; the slot tip angle is the inclination angle of the retracted profile.

[0015] Furthermore, the pole arc angle θ2 = 168°.

[0016] Furthermore, the thickness of the magnetic steel in the magnetic steel group is L5=5.2 mm, and the magnetic steel is inserted into the accommodating cavity in a radial insertion manner.

[0017] Furthermore, the magnetic steel adopts N52UH neodymium iron boron magnetic steel with a remanence of 1.46T and a maximum operating temperature of 180°C.

[0018] Furthermore, the group of magnetic steel groups forms a pole, and the pole includes 6 to 10 magnetic steels.

[0019] Furthermore, the winding is made of corona-resistant polyimide copper rectangular wire with a temperature resistance grade of 240°C.

[0020] Furthermore, the slot fill rate of the stator slots is 89.4%.

[0021] Furthermore, the stator slot is provided with insulating paper for isolating the inner wall of the stator slot from the winding; the insulating paper is made of DuPont Nomex T410 aramid insulating paper with a thickness of 0.25 mm; the gap of the winding in the stator slot is filled with insulating varnish, and the insulating varnish is made of VX4201 unsaturated polyester imide resin.

[0022] Furthermore, the stator core and the rotor core are formed by stacking sheets made of Hperco50 iron-cobalt-vanadium alloy with a thickness of 0.15 mm. The stacking height of the stator core and the rotor core is 65 mm, and the stacking coefficient is 0.97.

[0023] Furthermore, a heat sink is arranged on the outer periphery of the stator; the heat sink comprises a heat sink ring and a plurality of heat sinks arranged in an annular shape at equal angles along the outer periphery of the heat sink ring; the heat sink ring is tightly attached to the outer periphery of the stator core.

[0024] Compared with the prior art, the beneficial effects of the high torque density electric aircraft motor of the present invention are: through optimizing the design in the main aspects such as motor material selection, magnet arrangement method, pole skew processing method, winding form, etc., it is applied to electric propulsion aircraft; it adopts the radial insertion method of the inner rotor, 54 slots, 42 poles, and four-segment rotor core skew slot magnets, and has the performance of symmetrical magnetomotive force waveform, high winding coefficient, low torque pulsation and cogging torque, and no end circulation; the motor adopts centralized double winding and shell heat sink air cooling, and has the characteristics of large torque, light weight, simple cooling method, and large safety margin; the motor designed in this scheme can achieve higher torque density and power density while having stable and controllable heat generation and is not prone to burning.

Brief Description of the Drawings

[0025] Figure 1 is a schematic diagram of a cross-sectional structure of an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of the structure of the winding in the stator slot in an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of a local structure in an embodiment of the present invention;

[0028] Figure 4 This is a magnetomotive force waveform diagram of a motor using a 54-slot 42-pole matching method according to an embodiment of the present invention;

[0029] Figure 5 The winding coefficient distribution histogram of the motor using the 54-slot 42-pole matching mode according to the embodiment of the present invention;

[0030] Figure 6 The BH curve diagram of the Hperco50 iron-cobalt-vanadium alloy material according to the embodiment of the present invention;

[0031] Figure 7 This is an information diagram of the remanence, coercive force, and square coefficient Hk / Hcj of N52UH magnetic steel in an embodiment of the present invention;

[0032] Figure 8 This is a graph of electromagnetic simulation data at peak power in an embodiment of the present invention;

[0033] Fig. 9 It is a magnetic induction density cloud diagram at peak power in an embodiment of the present invention;

[0034] Fig.10 : is a diagram of magnetic induction intensity of each part at peak power in an embodiment of the present invention;

[0035] Fig.11 This is a loss distribution diagram obtained by simulation under peak power in an embodiment of the present invention;

[0036] Fig.12 TS curve diagram obtained by simulation under peak power in an embodiment of the present invention;

[0037] Fig.13 It is an efficiency MAP diagram obtained by simulation at peak power in an embodiment of the present invention;

[0038] Fig.14 This is a diagram of thermal simulation results at peak power in an embodiment of the present invention;

[0039] Fig.15 This is an electromagnetic simulation data diagram at rated power in an embodiment of the present invention;

[0040] Fig.16 It is a magnetic induction density cloud diagram under rated power in an embodiment of the present invention;

[0041] Fig.17 Magnetic induction intensity diagram of each part at rated power in an embodiment of the present invention;

[0042] Fig.18 This is a loss distribution diagram obtained by simulation under rated power in an embodiment of the present invention;

[0043] Fig.19 TS curve diagram obtained by simulation under rated power in an embodiment of the present invention;

[0044] Fig. 20 It is an efficiency MAP diagram obtained by simulation at rated power in an embodiment of the present invention;

[0045] Fig.21 This is a diagram of thermal simulation results at rated power in an embodiment of the present invention;

[0046] Fig. 22 This is a data diagram of simulation results under maximum torque in an embodiment of the present invention;

[0047] Fig.23 Magnetic induction density cloud diagram under maximum torque in an embodiment of the present invention;

[0048] Fig.24 Magnetic induction density diagram of each part under maximum torque in an embodiment of the present invention;

[0049] Figure 25-26 This is a simulation diagram of rotor strength in an embodiment of the present invention;

[0050] Fig. 27 It is a diagram of the simulation results of the cogging torque and torque ripple in the embodiment of the present invention;

[0051] Fig.28 This is a 2D spectrum of the time-dominant stator radial harmonics of an embodiment of the present invention;

[0052] Fig.29 A Campbell sound pressure field spectrum diagram according to an embodiment of the present invention;

[0053] Fig.30 - is a diagram of radial stress data of a stator according to an embodiment of the present invention;

[0054] Figure 31-33 The phase current curve, terminal voltage peak value and back electromotive force EMF curve diagram of the embodiment of the present invention;

[0055] The numbers in the figure represent:

[0056] 100-High torque density electric aircraft motors;

[0057] 1- stator, 11- stator core, 111- stator slot, 112- stator tooth, 113- insulating paper, 114- insulating paint, 12- winding; 2- rotor, 21- rotor core, 22- magnetic steel group; 3- heat sink, 31- heat sink ring, 32- heat sink. [Specific implementation method]

[0058] Embodiment 1:

[0059] Please refer to Figure 1-Figure 3 The present embodiment is a motor 100 for an electric aircraft with a high torque density, which includes a stator 1 , a rotor 2 disposed inside the stator 1 , and a heat sink 3 disposed outside the stator 1 .

[0060] The stator 1 includes a stator core 11 and a winding 12. The inner wall of the stator core 11 is provided with a plurality of stator slots 111 at equal angles along its own circumference, and each stator slot 111 is provided with a winding 12. A stator tooth 112 is formed between two adjacent stator slots 111. The outer diameter D1 of the stator core 11 is 355 mm, and the inner diameter D2 of the stator core 11 is 308.6 mm.

[0061] The rotor 2 includes a rotor core 21 and a magnetic steel group 22. The outer wall of the rotor core 21 is provided with a plurality of accommodating cavities (not shown) at equal angles along its own circumference, and each of the accommodating cavities is provided with a group of magnetic steel groups 22. The outer diameter D3 of the rotor core 21 is 306 mm, and the inner diameter D4 of the rotor core 21 is 286 mm.

[0062] The air gap L1 between the stator 1 and the rotor 2 is 1.3 mm, that is, the distance between the outer wall of the magnetic steel group 22 and the inner wall of the stator core 11. The main cross-sectional shape of the stator slot 111 is rectangular, and a retracted slot is formed on the side close to the inner wall of the stator core 11. The retracted profile is a straight line, and its slot width L2=3.5 mm, the slot depth L3 of the stator slot 111 is 18.7 mm, and the inclination angle of the retracted profile, that is, the slot tip angle θ1=28°, the stator slot 111 is a parallel slot, and its parallel slot width L4=9.4 mm. The pole arc angle θ2=168°, the magnetic steel thickness L5=5.2 mm. The magnetic steel adopts 52UH neodymium iron boron magnetic steel, the remanence is 1.46T, and the maximum operating temperature is 180°C.

[0063] The more slots there are in the stator slots 111, the lower the harmonic content of the motor will be, which can effectively reduce additional losses, reduce harmonic leakage reactance, and make the magnetic potential waveform closer to a sine wave, which is beneficial to increasing the motor torque. In addition, the total heat dissipation area of ​​the coil side in the slot is increased, which is beneficial to heat dissipation and reduces temperature rise. The number of rotor slots must be designed to match the number of stator slots. If the slots are not properly matched, the motor may fail to start, vibrate and make loud noises, and generate additional losses and additional torque. In this embodiment, the motor uses 54 slots and 42 poles. That is, the number of slots in the stator slots 111 on the stator core 11 is 54. The number of magnetic steel groups 22 on the outer wall of the rotor core 21 is 42 groups, forming 42 poles. Please refer to Figure 4-5 , Figure 4 This is a graph of the height of the magnetomotive force waveform of 54 slots and 42 poles. Figure 5 The histogram of winding coefficients for 54 slots and 42 poles is shown in Figure 2. Figure 4 It can be seen that the combination of 54 slots and 42 poles effectively avoids end circulation heating; Figure 5 It can be seen that the combination of 54 slots and 42 poles has a higher winding coefficient.

[0064] In this embodiment, one pole is composed of 5 magnetic steels. In other embodiments, one pole can also be composed of 3 or 4, or 6 to 10 magnetic steels. By segmenting the magnetic steel, the eddy current loss and heat generation of the magnetic steel during motor operation can be effectively reduced. In this embodiment, the magnetic steel adopts N52UH NdFeB magnetic steel. The coercive force and square coefficient Hk / Hcj information of N52UH NdFeB magnetic steel are as follows: Figure 7 As shown. Figure 7 It can be seen that N52UH NdFeB magnet can be used for a long time in the range of 180℃, the square coefficient is greater than 0.95, and the remanence Br is 1.46T.

[0065] To ensure sufficient starting torque, the current density cannot be too small, while too large a current density will increase the slip rate, increase the rotor resistance loss, reduce the efficiency, and increase the heat generation. In this embodiment, the winding 12 is wound in the form of a centralized winding and is a double winding, and is wound with a temperature-resistant grade of 240°C corona-resistant polyimide copper flat wire. The centralized winding is wound with 2 wires and 4 turns. By combining the centralized winding with the double winding form, the end height can be effectively reduced, thereby reducing the copper loss and heat generation when the motor is running; in addition, the double winding can also increase the motor safety margin, and the other can still operate when one is disconnected.

[0066] The filling rate of the stator slot 111 is 89% (including insulating paper). If the slot filling rate is too large, the winding will not be able to go into the slot; if the slot filling rate is too small, the slot utilization rate is too low, which is not conducive to the heat dissipation of the winding. In this embodiment, the filling rate of the stator slot 111 is designed to be 89%, which, together with the subsequent design of the size of the stator slot 111, not only ensures the feasibility of winding copper flat wire, but also has good heat dissipation performance.

[0067] The insulating paper 113 in the stator slot 111 is DuPont Nomex T410 aramid insulating paper with a thickness of 0.25 mm. The gap between the winding 12 and the stator slot 111 is filled with insulating varnish 114, and the insulating varnish uses VX4201 unsaturated polyester imide resin as the slot filling material.

[0068] The rotor 2 is subjected to a pole tilting treatment, specifically a four-stage pole tilting treatment, with angles of -0.5626°, -0.1875°, 0.1875°, and 0.5625°. By using a segmented pole tilting treatment with a set angle on the rotor, the torque pulsation and cogging torque of the motor are reduced; the vibration and noise of the motor are reduced.

[0069] In this embodiment, the stator core 11 and the rotor core 21 are made of Hperco50 iron-cobalt-vanadium alloy and are laminated with a thickness of 0.15 mm. The stacking height of the stator core 11 and the rotor core 21 is 65 mm, and the stacking coefficient is 0.97. Figure 6 , Figure 6 This is the BH curve of Hperco50 iron-cobalt-vanadium alloy material, which reflects the relationship between magnetic induction intensity and magnetic field intensity of Hperco50 iron-cobalt-vanadium alloy material during the magnetization process. It can be seen from the figure that the inflection point is greater than 2.3T and the saturation point is greater than 2.5T.

[0070] The heat sink 3 comprises a heat sink ring 31 and a plurality of heat sink fins 32 arranged in an annular shape at equal angles along the outer periphery of the heat sink ring 31. The heat sink ring 31 is tightly attached to the outer periphery of the stator core 11.

[0071] In order to verify that the motor designed in this embodiment has excellent performance, a thermal simulation test and an electromagnetic simulation test were performed on the motor, and the tests are as follows:

[0072] (1) Simulation condition input

[0073] Electromagnetic simulation input conditions: DC bus voltage range 600 ~ 710V, DC bus current 0 ~ 190A (rms), motor maximum speed 2200rpm; electromagnetic simulation software is Ansys Motor-CAD using Maxwell tensor method to simulate the motor, the air gap division number is 4 layers, the scanning angle is 360°, the electromagnetic wire, stator, and rotor division lengths are system defaults; the electromagnetic performance of the motor under DC bus voltage 600V and DC bus current 150A (rated power) and 190A (peak power) was simulated.

[0074] Thermal simulation input conditions: The maximum ambient temperature is 55°C, and the air that exchanges heat with the motor surface is 2000 liters per minute; at rated power: electrical load, electrical density, thermal load: 67.44A / mm, 12.78A / mm 2 ,861.89A 2 / mm 3 After thermal equilibrium, the maximum winding temperature is 155.1℃, and the magnetic steel is 106.2℃; at peak power: electrical load, electrical density, thermal equivalent: 85.43A / mm, 16.19A / mm 2 , 1383.07A 2 / mm 3 , after 120 seconds, the winding temperature reached a maximum of 157.7°C, and after 180 seconds it reached 177.6°C.

[0075] (2) Simulation process

[0076] (21) Electromagnetic simulation at peak power:

[0077] The current input is 190A, the voltage input is 600V, the lead angle is set to 10°, the winding copper wire temperature is set to 173℃, the magnetic steel is set to 157℃, the shaft temperature is set to 105℃, the maximum speed is 2200rpm, the iron loss coefficient Ka is 1.7, the electrical load, electrical density, and thermal equivalent are: 85.43A / mm, 16.19A / mm 2 、1383.07A 2 / mm 3 .

[0078] The electromagnetic simulation data at peak power is as follows Figure 8 The simulation results show that the maximum torque is 553.56Nm@1923rpm, the maximum efficiency is 96.32%, and the total loss is 4868.7W.

[0079] The magnetic induction density cloud diagram at peak power is as follows Fig. 9 As shown; the magnetic induction intensity of each part is as Fig.10 The simulation results show that the maximum magnetic induction intensity is located at the tooth part, with a maximum value of 2.425T, the average magnetic induction intensity of the air gap is 0.8012T, and the maximum magnetic induction intensity of the air gap is 1.287T.

[0080] The loss distribution obtained by simulation under peak power is as follows Fig.11 The simulation results show: peak shaft power 109.80KW, 553.56Nm@1923rpm, efficiency 96.32% (winding 173℃, magnet 157℃).

[0081] The TS curve obtained by simulation under peak power is as follows: Fig.12 The simulation results show that the maximum torque of 553.56Nm is met within the speed of 1923rpm, and the torque is still greater than 540Nm at the speed of 2200rpm.

[0082] The efficiency MAP diagram obtained by simulation at peak power is as follows Fig.13 The simulation results of the peak power efficiency MAP show that the motor efficiency is greater than 96% when the speed is between 1000rpm and 2200rpm.

[0083] (22) Thermal simulation at peak power:

[0084] When the aircraft climbs vertically at the rate of 3 meters per second, the motor housing displaces 2260.8 liters of air per minute. At an altitude of 3000 meters, the air displacement is 0.88 times the sea level. After comprehensive consideration, the amount of air in contact with the motor housing is 2000 liters per minute.

[0085] Thermal simulation results at peak power are shown below: Fig.14 The simulation results show that under an external environment of 55°C and at an altitude of 3,000 meters, the winding temperature is about 157.7°C after 120 seconds and 177.6°C after 180 seconds. The motor is in thermal equilibrium within 10 minutes of operation, with the winding temperature being about 211.5°C and the magnetic steel temperature being about 126.3°C. There is no winding burnout or magnetic steel demagnetization, showing a steady state.

[0086] (21) Electromagnetic simulation at rated power:

[0087] The current input is 150A, the voltage input is 600V, the lead angle is set to 10°, the winding copper wire temperature is set to 135℃, the magnetic steel is set to 130℃, the shaft temperature is set to 85℃, the maximum speed is 2200rpm, the iron loss coefficient Ka is 1.7, and the electrical load, electrical density, and thermal load are: 67.44A / mm, 12.78A / mm 2 、861.89A 2 / mm 3 .

[0088] Electromagnetic simulation data under rated power is as follows Fig.15 The simulation results show that the maximum torque is 455.09Nm@2018.8rpm, the maximum efficiency is 97.05% (winding 135℃, magnet 130℃), and the total loss is 3190.1W.

[0089] The magnetic induction density cloud diagram at rated power is as follows Fig.16 As shown, the magnetic induction intensity of each part is Fig.17 The simulation results show that the maximum magnetic induction intensity is located at the tooth part, with a maximum value of 2.365T, the average magnetic induction intensity of the air gap is 0.8252T, and the maximum magnetic induction intensity of the air gap is 1.297T.

[0090] The loss distribution obtained by simulation under rated power is as follows Fig.18 shown.

[0091] The TS curve obtained by simulation under rated power is as follows: Fig.19 The simulation results show that the maximum torque of 455.09Nm is met within the speed of 2018.8rpm, and the torque is still greater than 450Nm at 2200rpm.

[0092] The efficiency MAP obtained by simulation at rated power is as follows Fig. 20 The simulation results of the peak power efficiency MAP show that the motor efficiency is greater than 96.5% when the speed is between 1000 rpm and 2200 rpm.

[0093] (23) Thermal simulation at rated power:

[0094] When the aircraft climbs vertically at the rate of 3 meters per second, the motor housing displaces 2260.8 liters of air per minute. At an altitude of 3000 meters, the air displacement is 0.88 times the sea level. After comprehensive consideration, the amount of air in contact with the motor housing is 2000 liters per minute.

[0095] Thermal simulation results at rated power are as follows: Fig.21 The simulation results show that under an external environment of 55°C and at an altitude of 3,000 meters, the winding temperature is about 118.3°C after 120 seconds and 144.8°C after 300 seconds. The motor is in thermal equilibrium within 15 minutes of operation, with a winding temperature of 155.1°C and a magnetic steel temperature of about 106.2°C. There is no winding burnout or magnetic steel demagnetization.

[0096] (24) Maximum torque simulation:

[0097] Maximum torque electromagnetic simulation input conditions: current input 190A, voltage input 600V, lead angle set to 10°, winding copper wire temperature set to 20℃, magnetic steel set to 20℃, shaft temperature set to 20℃, maximum speed 2200rpm.

[0098] The maximum torque simulation result data is as follows Fig. 22 The simulation results show that the maximum torque is 650.89Nm, the maximum efficiency is 97.48%, and the total loss is 3879.4W.

[0099] The magnetic induction density cloud diagram at maximum torque is as follows Fig.23 As shown, the magnetic induction density of each part is Fig.24 The simulation results show that when the maximum torque is output, the highest magnetic induction intensity is 2.505, the maximum air gap magnetic flux density is 1.425T, and the average is 0.9505T.

[0100] (25) Rotor strength simulation. The simulation results are as follows: Figure 25-26 As shown, the results show that at a speed of 2200 rpm, the rotor is far from reaching the yield point of 393 MPa of Hperco50 material, and the actual maximum stress is less than 18 MPa.

[0101] (26)NVH performance test. The cogging torque and torque pulsation simulation results are shown in Fig. 27 The simulation results show that with the 4-stage rotor skew treatment, the torque ripple is less than 2% and the cogging torque is only 1.305Nm.

[0102] (27) The time-dominated stator radial harmonic 2D spectrum, such as Fig.28 The results in the figure show that the wave peaks are round and smooth, which effectively avoids the problem of motor howling during operation.

[0103] (28) Campbell sound pressure field spectrum, such as Fig.29 The results in the figure show that there are abnormal NVH conditions at spatial orders 6 and 12, corresponding to frequencies of 1500 to 2300 Hz, and corresponding to speeds above 4500 rpm (2200 rpm, 733.33 Hz).

[0104] (29) Stator radial stress data, such as Fig.30 shown.

[0105] (30) The phase current curve, terminal voltage peak value and back EMF curve are as follows: Figure 31-33 As shown in the figure, we can see that the peak value is 268.66A, the terminal voltage peak value is 684.1V, and the back EMF peak value is 589.8V@2200rpm.

[0106] After the above simulation experiments, the motor parameter list of this embodiment is shown in the following table.

[0107]

[0108]

[0109] For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, all of which fall within the protection scope of the present invention.

Claims

1. A high torque density electric aircraft motor, comprising a stator and a rotor arranged inside the stator; the stator comprises a stator core and a winding, the inner wall of the stator core is provided with a plurality of stator slots at equal angles along its own circumference, each of the stator slots is provided with the winding; the rotor comprises a rotor core and a magnetic steel group, the outer wall of the rotor core is provided with a plurality of accommodating cavities at equal angles along its own circumference, each of the accommodating cavities is provided with a group of magnetic steel groups; characterized in that: The number of the stator slots is 54, and the number of the magnetic steel groups is 42, forming a matching structure of 54 slots and 42 poles; The winding adopts a centralized double winding form; The stator core has an outer diameter D1 of 355 mm and an inner diameter D2 of 308.6 mm; The outer diameter D3 of the rotor core is 306 mm, and the inner diameter D4 is 286 mm; The air gap between the stator and the rotor is L1=1.3 mm; The slot width L2 of the stator slot is 3.5 mm, the slot depth L3 is 18.7 mm, the slot tip angle θ1 is 28°, and the stator slot is a parallel slot with a parallel slot width L4 of 9.4 mm; The rotor adopts four-stage tilted pole treatment, and the tilted pole treatment angles are: -0.5626°, -0.1875°, 0.1875°, and 0.5625° respectively.

2. The high torque density electric aircraft motor according to claim 1, characterized in that: A stator tooth is formed between two adjacent stator slots, and the air gap is formed between the inner wall of the stator tooth and the outer wall of the magnetic steel group.

3. The high torque density electric aircraft motor according to claim 1, characterized in that: The main cross-section of the stator slot is rectangular, and a retracted slot opening is formed on one side close to the inner wall of the stator core, and the retracted profile is a straight line; the slot tip angle is the inclination angle of the retracted profile.

4. The high torque density electric aircraft motor according to claim 1, characterized in that: The pole arc angle θ2 = 168°.

5. The high torque density electric aircraft motor according to claim 1, characterized in that: The magnetic steel in the magnetic steel group has a thickness L5 of 5.2 mm and is inserted into the accommodating cavity in a radial insertion manner.

6. The high torque density electric aircraft motor according to claim 1, characterized in that: The magnetic steel is N52UH neodymium iron boron magnetic steel with a remanence of 1.46T and a maximum operating temperature of 180°C.

7. The high torque density electric aircraft motor according to claim 1, characterized in that: The group of magnetic steels forms a pole, and the pole includes 6 to 10 magnetic steels.

8. The high torque density electric aircraft motor according to claim 1, characterized in that: The winding is made of corona-resistant polyimide copper flat wire with a temperature resistance grade of 240°C.

9. The high torque density electric aircraft motor according to claim 1, characterized in that: The slot filling rate of the stator slots is 89.4%.

10. The high torque density electric aircraft motor according to claim 1, characterized in that: Insulating paper is provided in the stator slot to isolate the inner wall of the stator slot from the winding; the insulating paper is DuPont Nomex T410 aramid insulating paper with a thickness of 0.25 mm; the gap of the winding in the stator slot is filled with insulating varnish, and the insulating varnish is VX4201 unsaturated polyester imide resin.

11. The high torque density electric aircraft motor according to claim 1, characterized in that: The stator core and the rotor core are made of Hperco50 iron-cobalt-vanadium alloy and are laminated with sheets having a thickness of 0.15 mm. The core stacking height of the stator core and the rotor core is 65 mm, and the stacking coefficient is 0.

97.

12. The high torque density electric aircraft motor according to claim 1, characterized in that: A heat sink is arranged on the outer periphery of the stator; the heat sink comprises a heat sink ring and a plurality of heat sinks arranged in an annular shape at equal angles along the outer periphery of the heat sink ring; the heat sink ring tightly embraces the outer periphery of the stator core.

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