WO2023020578A1

WO2023020578A1 - Permanent magnet brushless motor and manufacturing method therefor, multi-axis aircraft, and robot

Info

Publication number: WO2023020578A1
Application number: PCT/CN2022/113344
Authority: WO
Inventors: 潘韫哲
Original assignee: 上海舞肌科技有限公司
Priority date: 2021-08-19
Filing date: 2022-08-18
Publication date: 2023-02-23

Abstract

A permanent magnet brushless motor and a manufacturing method therefor, a multi-axis aircraft, and a robot. The permanent magnet brushless motor (100) is a fractional slot outer rotor motor, and the motor comprises a stator (1) and a rotor (2). The stator comprises a stator core (10) and a stator winding, and the stator winding is a non-staggered centralized winding having a span of 1. The rotor comprises a permanent magnet (21) and a rotor core (20). The stator core comprises a stator yoke portion (101) and a stator tooth portion, the stator tooth portion comprises a plurality of stator teeth (102) provided on the stator yoke portion, and an insulating layer is provided on the surface of each stator tooth. The stator winding comprises a plurality of winding coils (11) formed by machine winding, and each of the plurality of winding coils is symmetrically arranged on the corresponding stator tooth by using a radial center axis (103) corresponding to the stator tooth as an axis of symmetry.

Description

Permanent magnet brushless motor and manufacturing method thereof, multicopter and robot

technical field

At least one embodiment of the present disclosure relates to a permanent magnet brushless motor, a manufacturing method thereof, a multi-axis aircraft, and a robot.

Background technique

In recent years, multi-axis aircraft represented by multi-axis drones have developed rapidly, playing an important role in fields such as plant protection, aerial photography, delivery, reconnaissance, rescue, and survey. Multicopters place high demands on motors. With the same output power, a lighter and more efficient motor means that the load can be increased or the battery capacity can be increased, thereby improving the flight time and performance of the aircraft.

What restricts the progress of small brushless motors are mainly design and process problems. Many of the performance enhancements found in medium and large motors are not applicable to small motors. Therefore, how to design a high-performance small motor that can actually be manufactured is a difficult problem.

Contents of the invention

Embodiments of the present disclosure provide a permanent magnet brushless motor and its manufacturing method, a multi-axis aircraft, and a robot, which can significantly improve the slot fill rate of the motor, the motor constant per unit mass of the motor, and the output power density, and are suitable for small motors.

In the first aspect, an embodiment of the present disclosure provides a permanent magnet brushless motor, the motor is a fractional slot external rotor motor, the motor includes a stator and a rotor; the stator includes a stator core and a stator winding, and the stator The winding is a non-interlaced concentrated winding with a span of 1; the rotor includes a permanent magnet and a rotor core, wherein the permanent magnet is used for excitation to generate a rotating magnetic field, and the stator core includes a stator yoke and a stator tooth. The stator teeth part includes a plurality of stator teeth arranged on the stator yoke part, and an insulating layer is provided on the surface of each stator tooth; the stator winding includes a plurality of winding coils formed by machine winding, and the plurality of Each of the winding coils is symmetrically arranged on the corresponding stator tooth with the radial central axis corresponding to the stator tooth being a symmetrical axis.

For example, each of the winding coils includes a multi-layer cable from the inside to the outside, and the number of layers of the multi-layer cable is n layers, where n is an even number; the incoming line of the winding coil is close to the stator yoke side of the department.

For example, the wire of each said winding coil is a round wire with a circular cross section or a square wire with an approximately square cross section, the outer diameter of the strip of the round wire is dc, and the side length of the strip of the square wire is dc ,

when

When , the value range of dc is:

when

or

When , the value range of dc is:

in

or

q is 1/2 of the arc length between adjacent stator teeth in the axial section of the stator core and the tooth ends away from the stator yoke, p is the axial section of the stator core 1/2 of the arc length between the tooth roots of adjacent stator teeth close to the stator yoke.

For example, the stator teeth have the same width from a tooth end far away from the stator yoke to a tooth root close to the stator yoke; or from a tooth end far away from the stator yoke to a tooth root close to the stator At the root of the yoke, the width of the stator teeth gradually increases.

For example, the surface insulation layer of each stator tooth is an electrophoretic surface treatment layer or a vapor deposition surface treatment layer.

For example, the edges of the stator teeth extending from the tooth root to the tooth end are chamfered.

For example, the width of the narrowest part of the stator teeth is greater than or equal to 25% of the outer circumference/N of the outer diameter of the stator, and less than or equal to 60% of the outer circumference/N of the outer diameter of the stator, wherein , N is the number of the stator teeth.

For example, the width at the widest point of the stator teeth is less than or equal to 3.2mm.

For example, the thickness of the stator yoke is greater than or equal to 60% of the width of the stator teeth at the narrowest point, and less than or equal to 175% of the width of the stator teeth at the narrowest point.

For example, an air gap is formed between the stator and the rotor, and the average air gap distance of the motor is less than or equal to 0.6% of the outer diameter of the stator.

For example, the outer diameter of the stator core is less than or equal to 150mm.

For example, the axial height of the stator core is less than or equal to 25% of the outer diameter of the stator core.

For example, the average radial thickness of the permanent magnet is less than or equal to 20 times the average air gap distance and greater than or equal to 4.5 times the average air gap distance.

For example, the radial thickness of the rotor core is greater than or equal to 50% of the radial thickness of the permanent magnet, and less than or equal to 175% of the radial thickness of the permanent magnet.

For example, the motor is a three-phase motor, and the greatest common divisor C of the number of stator teeth/3 and the number of poles of the permanent magnet is greater than or equal to 2 and less than or equal to 8.

For example, the motor is a three-phase motor, and the number of teeth of the stator/C/3 winding coils are connected in series to form a minimum unit, and the minimum units are connected in series, parallel or mixed in series to form the stator of any phase. winding.

For example, the ratio of the number of poles of the permanent magnet to the number of teeth of the stator is greater than or equal to 0.78 and less than or equal to 1.34.

In the second aspect, the embodiments of the present disclosure also provide a method for manufacturing the above-mentioned permanent magnet brushless motor, including: preparing the stator core; preparing the winding coil of the stator winding, including: using a winding machine to wind the enameled wire The air-core coil is obtained after being wound on the skeleton; the air-core coil is sheathed and fixed on the stator core; the electrical connection of the coil includes: connecting the winding coil.

In the third aspect, the embodiments of the present disclosure further provide a multi-rotor aircraft, including the brushless permanent magnet motor described in any of the first aspects.

In a fourth aspect, embodiments of the present disclosure further provide a robot, including the permanent magnet brushless motor as described in any of the first aspects.

Embodiments of the present disclosure provide a permanent magnet brushless motor and its manufacturing method, a multi-axis aircraft, and a robot. The interference during winding improves the slot fill rate. Further, in the embodiment of the present disclosure: according to 1/2 of the arc length between adjacent stator teeth in the axial section of the stator core and the tooth ends far away from the stator yoke and the stator In the axial section of the iron core, 1/2 of the arc length between the tooth roots of adjacent stator teeth close to the stator yoke and in consideration of the number of winding layers, the wire of the winding coil is determined The outer diameter of the skin or the value range of the side length, so as to determine the size of the wire used in the winding coil according to the stator core, etc., so that the motor obtained by winding such a wire can significantly improve the slot fill rate and improve the motor. Torque density and motor constant per unit mass. Moreover, the determination of the outer diameter or side length of the above-mentioned wires is coordinated with other motor structural parameters, such as the width of the narrowest part of the stator teeth, the average air gap distance, the outer diameter and inner diameter of the stator, and the motor manufacturing process. , thereby optimizing the size and structure of the motor, making the wound coils consistent, compact, and safe, ensuring the stable assembly of the coil and the motor and maximizing the use of the space of the motor slot, while ensuring low cogging torque and the motor While running smoothly, the motors manufactured in large quantities have a high slot full rate and low DC and AC copper losses, thereby improving the torque density of the motor and the motor constant per unit mass.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present disclosure more clearly, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure .

FIG. 1 is a schematic structural diagram of a permanent magnet brushless motor provided by an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a permanent magnet brushless motor stator provided by an embodiment of the present disclosure;

Fig. 3 is another structural schematic diagram of the permanent magnet brushless motor stator provided by the embodiment of the present disclosure;

FIG. 4A is a top view of a winding coil provided by an embodiment of the present disclosure;

Fig. 4B is a cross-sectional view of the winding coil along the D-D line provided by the embodiment of the present disclosure;

FIG. 4C is an overall view of the winding coil provided by the embodiment of the present disclosure;

5 is a schematic diagram of the simulation effect of the width of the narrowest part of the stator teeth of the motor of the embodiment of the present disclosure/(the outer circumference of the outer diameter of the stator/the number of teeth) and the motor constant per unit weight;

6 is a schematic diagram of the simulation effect of the thickness of the stator yoke/the width of the narrowest part of the stator teeth and the motor constant per unit weight of the motor according to the embodiment of the disclosure;

7 is a schematic diagram of the simulation effect of the ratio of the average air gap distance to the outer diameter of the stator and the motor constant per unit weight of the motor according to an embodiment of the disclosure;

8 is a schematic diagram of the simulation effect of the ratio of the average radial thickness of the permanent magnet of the motor to the average air gap distance and the motor constant per unit weight of the embodiment of the present disclosure;

9 is a schematic diagram of the simulation effect of the ratio of the radial thickness of the rotor iron core to the radial thickness of the permanent magnet and the motor constant per unit weight of the motor according to an embodiment of the disclosure;

10 is a schematic diagram of the simulation effect of the ratio of the axial height h of the stator core of the motor to the outer diameter of the stator core and the motor constant per unit weight of the motor according to an embodiment of the disclosure;

11 is a schematic diagram of the relationship between the slot fullness ratio of the motor and the outer diameter of the belt or the side length dc of the belt according to an embodiment of the present disclosure; and

FIG. 12 is a flow chart of a manufacturing method of a motor according to an embodiment of the present disclosure.

100-motor, 1-stator, 10-stator core, 101-stator yoke, 102-stator teeth, 1021-tooth end, 1022-tooth root, 1023-tooth end extends to the edge of tooth root, 103- Radial central axis, 104-half of the stator slot, 110a-circumference of the winding coil near the tooth end, 110b-circumference of the winding coil near the tooth root, 11-winding coil, 2-rotor, 20-rotor iron core, 21-permanent magnet.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are some of the embodiments of the present disclosure, not all of them. Based on the described embodiments of the present disclosure, all other embodiments obtained by persons of ordinary skill in the art without creative effort fall within the protection scope of the present disclosure.

Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the usual meanings understood by those skilled in the art to which the present disclosure belongs. "First", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Comprising" or "comprising" and similar words mean that the elements or items appearing before the word include the elements or items listed after the word and their equivalents, without excluding other elements or items. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "Down", "Left", "Right" and so on are only used to indicate the relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

For motors with small torque and motors for drones, the performance and efficiency of the motor can be measured by the motor constant, which is defined as follows:

The motor of multi-axis aircraft, such as multi-axis drone, uses a stator with boots, and the winding coil is wound by a special stator winding machine, which greatly limits the slot fullness of the motor. Taking the common products on the market as an example, Generally, the full rate of motor slots of multi-axis aircraft is only about 30%, resulting in low power output per unit weight and unit volume, motor constant, and motor efficiency.

There are many studies on improving the torque performance of motors in academia. However, most of the researches focus on medium or large motors, which are mainly used in air compressors, industrial servos, new energy vehicles and wind turbines. For small motors and The research on torque performance and light weight of special motors for UAVs and high-performance robots is relatively limited. At the same time, the torque volume density, which is widely used in academia, is not completely suitable for small motors. In addition, the motors reported in academia often lack the feasibility of mass production due to factors such as cost, complexity, and consistency. Some seemingly promising designs with excellent performance lack realistic landing conditions, let alone miniaturization. motor.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, Figure 2 and Figure 3, the embodiment of the present disclosure provides a permanent magnet brushless motor 100, the motor 100 is a fractional slot external rotor motor, the motor includes a stator 1 and a rotor 2; The stator 1 includes a stator core 10 and a stator winding, the stator winding is a non-interlaced concentrated winding with a span of 1; the rotor 2 includes a permanent magnet 21 and a rotor core 20, wherein the permanent magnet 21 is used for excitation To generate a rotating magnetic field, the stator core 10 includes a stator yoke portion 101 and a stator tooth portion, the stator tooth portion includes a plurality of stator teeth 102 arranged on the stator yoke portion, and the surface of each stator tooth 102 is set There is a surface insulating layer; the stator winding includes a plurality of winding coils 11 formed by machine winding, and each of the plurality of winding coils 11 is symmetrically arranged on the radial center axis 103 corresponding to the stator tooth 102. on the corresponding stator teeth 102 .

For example, the surface insulation layer provided on the surface of each stator tooth 102 can ensure the insulation of the stator winding and the stator core, and avoid electric leakage. In an embodiment of the present disclosure, the surface insulating layer may be an electrophoretic surface treatment layer, that is, an electrophoretic surface treatment layer is formed on the surface of each stator tooth by electrophoretic treatment as a surface insulating layer. Electrophoretic (electro-coating or E-coating) surface treatment is also called electrophoretic coating treatment. In another embodiment of the present disclosure, the surface insulating layer may be a vapor deposition surface treatment layer. Vapor deposition surface treatment refers to the process of forming a coating on the surface of a workpiece with gaseous substances. Vapor deposition can be divided into physical vapor deposition and chemical vapor deposition. The present disclosure does not limit the method and type of vapor deposition. Alternatively, the surface insulating layer has both electrophoretic and vapor deposition surface treatments. Vapor deposition surface or electrophoretic surface treatment is stable, with good consistency and adhesion, good pressure resistance, and thin covering layer, which can reserve more space for copper wires and greatly improve the motor slot full rate.

For example, the winding coil 11 can be sleeved and installed on the stator teeth 102 after being machined and formed. The winding coil 11 processed by the machine can be isolated, that is, each coil has two disconnected lead wires, or it can be several winding coils directly connected by the machine.

For example, in some embodiments of the present disclosure, the connection of the winding coils to the winding coils can be completed by soldering on the printed circuit board, or by soldering wires in the air. Embodiments of the present disclosure do not limit the manner of connecting the winding coils to the winding coils.

There is a winding technology in which the winding coil is directly wound on the stator tooth by a special stator winding machine, so that the stator tooth and the winding coil on it will cause certain interference to the winding process of the adjacent winding coil, making the adjacent winding The gap between the coils is usually greater than 2-3 mm; in addition, the commonly used robot motor windings are arranged irregularly, and these factors seriously affect the slot fullness of the motor. After being molded, it is set on the stator teeth, so that there is no interference in the processing of the winding coils, so the winding coils obtained by winding are easier to meet the design requirements, so that the gap between adjacent winding coils is greatly reduced, which can greatly improve the performance of the motor. Slot full rate. Moreover, in the embodiments of the present disclosure, the coils wound by the machine are neatly arranged and have a high filling rate, which can further increase the torque density of the motor, the motor constant and the output power density of the motor, and improve the performance of the motor. For small-sized unmanned robots and robots, such high-performance motors can further improve device performance.

For example, in the embodiment of the present disclosure, as shown in FIG. 2 , from the tooth end 1021 away from the stator yoke 101 to the tooth root 1022 close to the stator yoke 101 , the width of the stator teeth 102 is the same everywhere, so as to facilitate corresponding winding coils. 11, and can improve space utilization, thereby increasing the motor constant per unit weight. It can be understood that, in some examples, from the tooth end 1021 far away from the stator yoke 101 to the tooth root 1022 close to the stator yoke 101 , the width of the stator teeth can also gradually increase. It should be noted that in commonly used UAV motors, the stator teeth are generally in a T-shaped structure (that is, the stator teeth have a boot structure), and the stator teeth with boots will affect the size of the winding coil cavity, thereby reducing the winding capacity. Coil space utilization. However, in the embodiments of the present disclosure, the stator teeth are not formed with boots, and the removal of the boots improves the space utilization of the winding coils, which is beneficial to further increase the motor constant per unit weight and improve the performance of the motor.

For example, in the embodiments of the present disclosure, the stator core 10 may be a one-piece core. It should be noted that the integrated iron core is different from a plurality of modules or partially assembled iron cores, and an iron core formed by stacking integral punched sheets also belongs to the integrated iron core referred to in the embodiments of the present disclosure. For example, the stator core 10 may be formed by laminating silicon steel sheets or soft magnetic material sheets. The one-piece iron core is easy to process, with mature technology and low cost.

For example, in the embodiment of the present disclosure, the edge 1023 of the stator tooth 102 extending from the tooth end to the tooth root is chamfered. As shown in FIG. 2 , the edges of the stator teeth 102 extending from the tooth root portion 1022 to the tooth end portion 1021 are formed to have a chamfered structure. In some embodiments, the tooth end edges and/or the tooth roots of the stator teeth 102 are also chamfered. Due to the limitation of the mechanical properties of the material, the inner wall of the winding coil cannot be made into a perfect right angle, and a certain rounded corner will be formed. The chamfered stator teeth 102 can adapt to the fillet of the inner wall of the coil, reduce unnecessary copper in the motor, and improve the operating efficiency of the motor. It should be noted that, in the embodiments of the present disclosure, the chamfered structure is a structure formed by processing a sharp edge into a blunt edge, and the blunt edge after the chamfering treatment can be an obtuse edge, a circular arc edge or other The edge is not sharp, which is not limited by the embodiments of the present disclosure.

For example, in an embodiment of the present disclosure, in order to further improve the firmness of the combination of the winding coil 11 and the stator tooth 102 , the stator 1 may further include an adhesive layer; the winding coil 11 is fixed to the stator tooth 102 through the adhesive layer. Wherein, the adhesive layer may be formed after the glue evenly coated on the surface of the stator tooth 102 or the inner surface of the winding coil 11 is cured. Specifically, glue can be evenly coated on part or all of the surface of the stator tooth 102, and then the winding coil 11 is placed on the stator tooth 102, and an adhesive layer is formed after the glue is cured, so that the winding coil 11 and the stator tooth 102 are fixed together, Not easy to loose. In some embodiments of the present disclosure, the adhesive layer can be formed by curing the glue coated on and covering the axial surface of the winding coil 11 installed on the stator tooth 102, by fixing the passing winding coil 11 and the winding coil 11 The relative position is such that the winding coil 11 is fixed on the stator tooth 102 without loosening. The present disclosure does not limit the specific implementation forms and methods of the adhesive layer.

For example, in the embodiments of the present disclosure, the size and structure of the motor are also designed, so that the performance of the motor can be improved, the production feasibility of the motor can be improved, and excellent motor constants can be obtained. Examples of motor dimensions and construction are as follows:

In the motor of the embodiment of the present disclosure, referring to FIG. 2 , the width of the stator teeth 102 is w, the diameter of the circle where the outer diameter of the stator core 10 is located is d2, and the circumference of the circle where the outer diameter of the stator core 10 is located, that is, The circumference of the outer circle where the outer diameter of the stator 1 is located is d2×π, which is denoted as p1. The width of the narrowest part of the stator tooth 102 may be greater than or equal to 25% of the circumference p1/N of the outer diameter of the stator, and may be less than or equal to 60% of the outer circumference p1/N of the outer diameter of the stator, where N is the stator The number of teeth 102.

For the width of the stator tooth 102 is the same everywhere from the tooth end 1021 to the tooth root 1022, the width of the narrowest part of the stator tooth 102 is the width of the stator tooth 102, and for the motor whose width of the stator tooth 102 is not the same everywhere, the stator tooth The width of the narrowest part of 102 is the minimum width of the stator teeth.

For example, in the embodiment of the present disclosure, the number of stator teeth 102 may be 48. Fig. 5 shows that when the number N of stator teeth 102 is 48, the simulation effect schematic diagram of the width of the narrowest part of the stator teeth/(the outer circumference of the outer diameter of the stator/the number of teeth) and the motor constant per unit weight, as shown in Fig. 5 As shown, when the width of the narrowest part of the stator tooth 102 is greater than or equal to 25% of the outer circumference p1/N of the outer diameter of the stator and less than or equal to 60% of the outer circumference p1/N of the outer diameter of the stator, the unit Weight of the motor constant in approx.

to appointment

In particular, compared with the motor in the prior art, the motor of the embodiment of the present disclosure having the above structure significantly improves the motor constant of the motor per unit weight, and improves the output efficiency of the motor.

Further, in the motor of the embodiment of the present disclosure, referring to FIG. 2 , the thickness of the stator yoke 101 is L, and the thickness L can be set to be greater than or equal to 60% of the width of the narrowest part of the stator teeth, and less than or equal to the width of the stator teeth. 175% of the width w at the narrowest point of the tooth. FIG. 6 shows a schematic diagram of the simulation effect of the thickness of the stator yoke/the width of the narrowest part of the stator teeth and the motor constant per unit weight when the number N of the stator teeth 102 is 48. As shown in Figure 6, when the thickness of the stator yoke is greater than or equal to 60% of the width at the narrowest part of the stator teeth and less than or equal to 175% of the width w at the narrowest part of the stator teeth, the motor constant per unit weight is about

to appointment

In particular, compared with the motor in the prior art, the motor of the embodiment of the present disclosure having the above structure significantly improves the motor constant of the motor per unit weight, and improves the output efficiency of the motor. It should be noted that, in some embodiments, when the thickness of the stator yoke varies with the angle, the thickness of the stator yoke should be understood as the average radial thickness or the equivalent radial thickness of the stator yoke in the magnetic circuit. thickness.

Further, in the motor of the embodiment of the present disclosure, referring to FIG. 1 , an air gap is formed between the stator 1 and the rotor 2, and the average air gap distance of the motor is g, and the average air gap distance g of the motor can be less than or Equal to 0.6% of the outer diameter d2 of the stator. Fig. 7 shows a schematic diagram of the simulation effect of the ratio of the average air gap to the outer diameter of the stator and the motor constant per unit weight of the motor according to the embodiment of the disclosure. As shown in Figure 7, as the ratio of the average air gap to the outer diameter of the stator increases, the motor constant per unit weight tends to decrease gradually, when the average air gap distance g of the motor is less than or equal to the outer diameter d2 of the stator 0.6%, the motor constant per unit weight is greater than or equal to

Compared with the motor in the prior art, the motor with the above structure significantly improves the motor constant per unit weight of the motor and improves the output efficiency of the motor.

Further, in the motor of the embodiment of the present disclosure, referring to FIG. 1 , the average radial thickness of the permanent magnet 21 is t, and the average radial thickness t of the permanent magnet 21 may be less than or equal to 20 times the average air gap distance g , and may be greater than or equal to 4.5 times the average air gap distance g. Fig. 8 shows a schematic diagram of the simulation effect of the ratio of the average radial thickness of the permanent magnet to the average air gap distance and the motor constant per unit weight. As shown in Fig. 8, when the ratio of the average radial thickness of the permanent magnet to the average air gap distance is between 4.5 and 20, the motor constant per unit weight can be in

arrive

Between, compared with the motor in the prior art, the motor with the above structure significantly improves the motor constant per unit weight of the motor, and improves the output efficiency of the motor.

Further, in the motor of the embodiment of the present disclosure, the radial thickness of the rotor core 20 is dr, and the radial thickness dr of the rotor core 20 may be greater than or equal to 50% of the radial thickness t of the permanent magnet 21 and It may be less than or equal to 175% of the radial thickness t of the permanent magnet. FIG. 9 shows a schematic diagram of the simulation effect of the ratio of the radial thickness of the rotor core to the radial thickness of the permanent magnet and the motor constant per unit weight. As shown in Fig. 9, when the ratio of the radial thickness of the rotor core to the radial thickness of the permanent magnets varies from 0.50 to 1.73, the motor constant per unit weight can be in

arrive

Between, compared with the motor in the prior art, the motor with the above structure significantly improves the motor constant per unit weight of the motor, and improves the output efficiency of the motor. It should be noted that, in some embodiments, when the radial thickness of the rotor core or the radial thickness of the permanent magnet varies with the angle, the radial thickness of the rotor core or the radial thickness of the permanent magnet should be understood as the average Radial thickness or equivalent radial thickness in a magnetic circuit.

In the motor of the embodiment of the present disclosure, the outer diameter d2 of the stator core 10 may be less than or equal to 150 mm.

In the motor of the embodiment of the present disclosure, the axial height h of the stator core 10 may be less than or equal to 25% of the outer diameter d2 of the stator core. In Fig. 1, Fig. 2 and Fig. 3, the axial height h of the stator The height of the iron core 10 perpendicular to the paper. Fig. 10 shows a schematic diagram of the simulation effect of the ratio of the axial height h of the stator core to the outer diameter of the stator core and the motor constant per unit weight. As shown in Figure 10, when the ratio of the axial height h of the stator core to the outer diameter of the stator core gradually increases, the motor constant per unit weight gradually decreases, and when the axial height h of the stator core is compared to the stator iron When the ratio of the outer diameter of the core is less than 0.25, the motor constant per unit weight can be greater than

It should be noted that the settings of the above-mentioned structural dimensions in the embodiments of the present disclosure are proposed by the inventor after comprehensive consideration of factors such as the difficulty of process implementation, the electromagnetic performance of the motor, the actual operating conditions, and the application scenarios. The motor with the above-mentioned size and structure can make the manufacturing, processing and assembly of the motor less difficult, and is conducive to improving the slot filling rate and increasing the air gap area, thereby increasing the torque density of the permanent magnet brushless motor and improving the performance of the motor.

In an embodiment of the present disclosure, the width at the widest point of the stator teeth may be less than or equal to 3.2 mm. In this way, the ineffective and non-working end windings can be reduced, and the operating efficiency and torque performance of the motor can be improved.

In the embodiment of the present disclosure, each stator tooth is covered with a winding coil, as shown in Figures 4A, 4B and 4C, Figure 4A shows a top view of the winding coil 11, and Figure 4B shows a view taken along the D-D line A cross-sectional view of the winding coil, FIG. 4C shows an overall view of the winding coil 11, for each stator tooth, the winding coil 11 forms several layers of wiring from the inside to the outside, wherein the number of layers n of the winding coil wiring is an even number, The incoming wire of the winding coil is on the side close to the stator yoke. It should be pointed out here that the number of wiring layers refers to the maximum number of layers, and the number of wiring layers in some areas can be less than n, for example, it can be n-1 layers of wiring, and from the inside to the outside means from the center of the stator teeth to the outside. As shown in FIG. 4B, the number of layers of the winding coil can be, for example, 4 layers from the inside to the outside. It should be pointed out here that the number of wiring layers refers to the maximum number of layers, and the number of wiring layers in some areas can be less than 4. Coils with even-numbered layers of wires can keep the fragile and easy-to-loose wire entry and exit ends of the wound coil away from the rotor, thereby preventing the rotor from contacting the wires during operation and causing damage.

In the embodiment of the present disclosure, as shown in FIG. 4A, FIG. 4B, and FIG. 2, the wires of each of the winding coils are round wires with a circular cross section or square wires with an approximately square cross section. The outer diameter of the belt skin is dc, and the length of the belt skin side of the square line is dc,

when

When , the value range of dc is:

when

or

When , the value range of dc is:

in

or

Wherein, q is 1/2 of the arc length between the tooth ends 1021 of the adjacent stator teeth away from the stator yoke in the axial section of the stator core, and p is the axis of the stator core 1/2 of the arc length between the root portions 1022 of the adjacent stator teeth in the cross-section, which are close to the stator yoke.

It should be noted that, due to the limitation of the processing technology, there may be fillets or chamfers at the ends of p and q, resulting in a larger arc length at the opening of the actual stator core or a smaller arc length at the junction of adjacent stator teeth. At this time, the values of p and q are the imaginary arc lengths without rounded corners or chamfers; due to the limitation of processing technology, the actual cross-sectional shape of the square line may be a rounded rectangle with similar length and width.

In an embodiment of the present disclosure, as shown in FIG. 2 , the half 104 of the stator slot that can accommodate the conductor can be approximately regarded as a right-angled trapezoid. The cross-section of the coil can be roughly divided into a wide part and a narrow part, and maximizing the slot fill rate means maximizing the sum of the areas of the wide part and the narrow part. Establishing a mathematical model based on this shows that, in order to achieve the highest slot fill rate, the size of the conductor needs to satisfy certain relationships. Considering factors such as machining error, discontinuity of slot fullness rate as a function, error caused by model approximation, etc., the above range is obtained as the value range of dc.

For example, for further understanding, in an example of the present disclosure, q is 1.57, p is 1.02, and the cross-section of the conductor is circular. when

And when n=2,

The conductor size is: 0.4876≤dc≤0.5406, corresponding to the slot full rate of 0.61; when

And when n=4,

The conductor size is: 0.3128≤dc≤0.3468, corresponding to a slot fullness rate of 0.67. when

And when n=2,

The wire diameter range is: 0.5436≤dc≤0.6027, and the corresponding slot full rate is 0.64; when

And when n=4,

The wire diameter range is: 0.3435≤dc≤0.3808, and the corresponding slot full rate is 0.74.

Therefore, above 0.4876 ≤ dc ≤ 0.5406, 0.3128 ≤ dc ≤ 0.3468, 0.5436 ≤ dc ≤ 0.6027, 0.3435 ≤ dc ≤ 0.3808 and the dc range obtained by even numbers such as 6, 8, 10, etc. are the range of the conductor size dc range of possible values. It should be noted that, for the convenience of comparison, the method of calculating the slot fullness rate in this embodiment is the ratio of the cross-sectional area of the stripped conductor to the slot.

In the embodiment of the present disclosure, Fig. 11 shows the relationship between the groove fill rate and the outer diameter of the belt or the side length dc of the belt, and the shaded area is the range proposed in this embodiment. According to the selection method provided in this embodiment, the slot fullness rate can be significantly increased, up to 0.75, which is significantly improved compared with the prior art, and is of great significance for reducing the copper loss of the motor and improving the operating efficiency and torque performance.

In this embodiment, as shown in FIG. 4C , from near the stator yoke 101 to away from the stator yoke 101, the circumference of the winding coil on the stator tooth 102 tends to increase or remain unchanged, that is, the winding coil near the tooth root 1022 The perimeter 110b of the coil may be less than or equal to the perimeter 110a of the winding coil near the tooth end 1021 .

It should be noted that the setting of the above-mentioned structural dimensions in this embodiment is proposed by the inventor after comprehensive consideration of factors such as the difficulty of process implementation, the electromagnetic performance of the motor, the actual operating conditions and application scenarios. In this embodiment, the above-mentioned optimization is made to the relevant dimensions of the motor, so that the wound coil has consistency, compactness, and safety, ensures the stable assembly and cooperation of the coil and the motor, and maximizes the use of the space of the motor slot. While the torque is low and the motor can run smoothly, the motors manufactured in large quantities have a high slot full rate and low DC and AC copper losses, thereby improving the torque density of the motor and the motor constant per unit mass.

As shown in FIG. 1 , in the embodiment of the present disclosure, the permanent magnet 21 is disposed on the inner surface of the rotor core 20 . The permanent magnet 21 can be made of NdFeB magnets.

As an implementation, the permanent magnet 21 in this embodiment includes several permanent magnet blocks, and each of the permanent magnet blocks is attached to the inner surface of the rotor core 20, that is, the permanent magnet blocks are surface-mounted permanent magnet blocks. .

As another implementation manner, the permanent magnet 21 may be a one-piece ring structure, sleeved and fixed on the inner surface of the rotor core 20 . The permanent magnet 21 can be fixed on the inner surface of the rotor iron core by glue.

As shown in FIG. 1 , in the embodiment of the present disclosure, the pole arc coefficient of the permanent magnet 21 is 1.

In the embodiment of the present disclosure, the motor 100 is a three-phase motor, the number of stator teeth/3, that is, N/3, and the greatest common divisor C of the number of permanent magnet poles P can be greater than or equal to 2, less than or equal to 8, that is, C= GCD(N/3,P), and 2≤C≤8, where GCD represents the greatest common divisor operation; the number of stator teeth/C/3 winding coils are connected in series to form the minimum unit, and the minimum units are connected in series, parallel or series-parallel connection to form the stator winding of any phase.

For example, the ratio of the number of poles P of the permanent magnet to the number of teeth N of the stator teeth, that is, P/N, may be greater than or equal to 0.78 and less than or equal to 1.34.

It should be noted that the above-mentioned electromagnetic setting in this embodiment is proposed by the inventor after considering factors such as the difficulty of process implementation and the comprehensive electromagnetic performance of the motor. In this embodiment, by optimizing the motor settings, the difficulty of manufacturing, processing and assembling of the motor is low, there are few invalid connection parts, the processing difficulty is low, it is easy to automate, the specific process is reduced, the management cost is reduced, and the motor has a wider speed regulation. Space and more general operating conditions without sacrificing the torque density and motor constant of the motor.

In the embodiment of the present disclosure, the number of stator teeth can be 48, that is, N=48, and the number of poles is 52, that is, P=52, that is, C=GCD(16,52)=4, N/C/3=4 , P/N=1.083. This number of tooth poles has better overall performance: lower cogging torque, running noise and better moment performance. In this embodiment, the resistance of the stator winding can be adjusted by changing the series-parallel connection of the winding coils in the stator winding to achieve the purpose of setting different operating voltages and rated speeds, which saves the trouble of changing the diameter of the motor winding coil and simplifies the manufacturing process.

For example, in the weight range of 10g to 1.5kg, and the stator core diameter range of 10mm to 150mm, the motor constant per unit mass of the motor provided by the embodiments of the present disclosure can reach

And it has realistic manufacturing and mass production feasibility, which is significantly improved compared with the prior art. When the weight of the motor is equal or similar, the working voltage is the same, and the heat dissipation is good, the output power of the permanent magnet brushless motor in this embodiment can be increased by more than 30%, or the same power output, efficiency or force effect can reduce the weight by more than 25%.

Embodiments of the present disclosure also provide a method for manufacturing a permanent magnet brushless motor. The permanent magnet brushless motor is as described above. As shown in FIG. 12 , the manufacturing method includes:

Prepare the stator core;

preparing a winding coil of the stator winding to obtain an air-core coil;

Sleeve and fix the hollow coil on the stator core;

Make the electrical connections of the winding coils.

For example, preparing the winding coil of the stator winding to obtain the air-core coil may include: using a winding machine to wind the enameled wire on the skeleton to form the air-core coil.

For example, performing the electrical connection of the winding coils may include: connecting the winding coils according to the specified connection mode of the windings of the motor,

The stator includes a stator core and a stator winding.

For example, in this manufacturing method, for each stator tooth, the winding coil 11 forms several layers of wiring from the inside to the outside, wherein the number n of winding coil wiring layers is an even number, and it should be pointed out here that the number of wiring layers Refers to the maximum number of layers, and the number of layers in some areas can be less than n. For example, it can be n-1 layers of wires. From the inside to the outside means from the center of the stator teeth to the outside. The wire of each winding coil is a round wire with a circular cross section or a square wire with an approximately square cross section, the outer diameter of the strip of the round wire is dc, and the strip side length of the square wire is dc, q is 1/2 of the arc length between the tooth ends 1021 of the adjacent stator teeth away from the stator yoke in the axial section of the stator core, p is the stator core of the stator winding 1/2 of the arc length between the root portions 1022 of the adjacent stator teeth near the stator yoke in the axial section.

Preparing the winding coil of the stator winding to obtain the air-core coil may also include: determining the range of the skinned outer diameter dc of the round wire or determining the range of the skinned side length dc of the square wire, so as to select the wire to prepare the winding coil .

For example, determining the range of the outer diameter dc of the strip of the round wire or determining the range of the side length dc of the strip of the square wire to select the wire to prepare the winding coil may include:

when

, determine the value range of dc as:

when

or

, determine the value range of dc as:

in

or

For example, preparing the stator core may include: forming the stator core, chamfering the edge of the tooth body of the stator core, and surface treatment of the stator core.

For example, in the embodiments of the present disclosure, there is no order in the preparation of the stator core and the winding coils of the stator winding. The winding coils can be prepared first and then the stator core, or the stator core can be prepared first and then the winding coils can be prepared. Or both are performed simultaneously, which is not limited by the embodiments of the present disclosure.

For example, the preparation of the stator core can include: the forming of the stator core can be formed by stamping silicon steel sheets and stacking them; the chamfering of the edge of the stator core tooth body refers to processing the sharp edge of the stator core tooth body The process of sharp edges, the non-sharp edges after chamfering can be obtuse edges, arc edges or other non-sharp edges, and this invention is not limited; the surface treatment of the stator core refers to the electrophoretic paint through electrochemical adhesion The process of attaching the paint film to the stator core or the stator core by vapor deposition.

For example, preparing the winding coil of the stator winding to obtain the air-core coil may include: using a winding machine to wind the enameled wire on the frame to form the air-core coil. A winding machine is any device that converts wire into coils.

For example, the fixing of the coil and the stator core may include: sheathing and fixing the hollow coil on the completed stator core; if necessary, applying glue to the teeth of the stator core or the cavity of the hollow coil before sheathing , and cure the glue after setting; or, in other embodiments, the glue can be applied to the axial surface of the winding coil after setting, and the winding coil can be fixed by fixing the relative position of the winding coil and the winding coil It is fixed on the stator teeth without loosening.

For example, the electrical connection of the coils may include: connecting the coils in a prescribed connection manner for the motor windings. In one embodiment, the electrical connection part of the coil is directly connected to the coil during the preparation process of the coil, and part is soldered on the printed circuit board; in other embodiments, the electrical connection between the coil and the coil can also be connected through the coil and the coil Air wiring, terminal wiring, aerial welding and other methods. It should be noted that the electrical connection of the coil can occur after the fixed time sequence of the coil and the iron core; it can also be during the preparation of the coil; or before the fixing of the coil and the stator core; it can also be partially occurred between the coil and the iron core. Before the iron core is fixed, partly during the preparation of the coil, partly after the coil and the iron core are fixed.

Embodiments of the present disclosure also provide a multi-rotor aircraft, including the permanent magnet brushless motor as described above.

An embodiment of the present disclosure also provides a robot, including the permanent magnet brushless motor as described above.

Embodiments of the present disclosure provide a permanent magnet brushless motor and its manufacturing method, a multi-axis aircraft, and a robot. The interference during winding improves the slot fill rate. Further, in the embodiment of the present disclosure: according to 1/2 of the arc length between adjacent stator teeth in the axial section of the stator core and the tooth ends far away from the stator yoke and the stator In the axial section of the iron core, 1/2 of the arc length between the tooth roots of adjacent stator teeth close to the stator yoke and in consideration of the number of winding layers, the wire of the winding coil is determined The numerical range of the outer diameter of the belt or the length of the side, thereby significantly improving the slot fullness rate, improving the torque density of the motor and the motor constant per unit mass. Moreover, the determination of the outer diameter or side length of the above-mentioned wires is coordinated with the setting of other motor structural parameters and the manufacturing process of the motor, thereby optimizing the size and structure of the motor, ensuring low cogging torque and smooth operation of the motor At the same time, it makes the wound coils consistent, compact and safe, ensures the stable assembly and cooperation of the coil and the motor, and maximizes the use of the space of the motor slot, so that the motor slots manufactured in large quantities have a high fill rate, and the DC and AC copper losses are low. Thereby improving the torque density of the motor and the motor constant per unit mass.

For this disclosure, the following points need to be explained:

(1) The drawings of the embodiments of the present disclosure only relate to the structures involved in the embodiments of the present disclosure, and other structures may refer to general designs.

(2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thicknesses of layers or regions are exaggerated or reduced, that is, the drawings are not drawn in actual scale.

(3) In the case of no conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and the protection scope of the present disclosure should be based on the protection scope of the claims.

This application claims the priority of Chinese Patent Application No. 202110956438.7 filed on August 19, 2021 and Chinese Patent Application No. 202121955646.7 filed on August 19, 2021, the entire contents of which are incorporated by reference in This is taken as part of this application.

Claims

A permanent magnet brushless motor, the motor is a fractional slot external rotor motor, and the motor includes a stator and a rotor;

The stator includes a stator core and a stator winding, and the stator winding is a non-staggered concentrated winding with a span of 1;

The rotor includes permanent magnets and a rotor core,

Wherein the permanent magnet is used for excitation to generate a rotating magnetic field,

The stator core includes a stator yoke and a stator tooth, the stator tooth includes a plurality of stator teeth arranged on the stator yoke, and an insulating layer is provided on the surface of each stator tooth;

The stator winding includes a plurality of winding coils formed by machine winding, and each of the plurality of winding coils is symmetrically arranged on the corresponding stator tooth with the radial central axis corresponding to the stator tooth as a symmetrical axis.
The permanent magnet brushless motor according to claim 1, wherein each of said winding coils includes a multilayer cable from inside to outside, and the number of layers of said multilayer cable is n layers, and n is an even number; said The incoming wire of the winding coil is on the side close to the stator yoke.
The permanent magnet brushless motor according to claim 1, wherein the wire of each said winding coil is a round wire with a circular cross section or a square wire with an approximately square cross section, and the outer diameter of the strip of the round wire is dc , the stripped side length of the square line is dc,

when
When , the value range of dc is:

when
or
When , the value range of dc is:

in
or

q is 1/2 of the arc length between adjacent stator teeth in the axial section of the stator core and the tooth ends away from the stator yoke, p is the axial section of the stator core 1/2 of the arc length between the tooth roots of adjacent stator teeth close to the stator yoke.
The permanent magnet brushless motor according to any one of claims 1-3, wherein the width of the stator teeth is the same from the tooth end far away from the stator yoke to the tooth root close to the stator yoke ;or

The width of the stator teeth gradually increases from a tooth end far away from the stator yoke to a tooth root close to the stator yoke.
The permanent magnet brushless motor according to claim 1, wherein the surface insulation layer of each stator tooth is an electrophoretic surface treatment layer or a vapor deposition surface treatment layer.
The permanent magnet brushless motor according to claim 4, wherein the edges of the stator teeth extending from the tooth root to the tooth end are chamfered.
The permanent magnet brushless motor according to claim 1, wherein the width of the narrowest part of the stator teeth is greater than or equal to 25% of the outer circumference/N of the outer diameter of the stator, and less than or equal to the outer diameter of the stator. 60% of the circumference of the outer circle where the diameter is located/N, where N is the number of the stator teeth.
The permanent magnet brushless motor according to claim 7, wherein the width of the stator teeth at the widest point is less than or equal to 3.2 mm.
The permanent magnet brushless motor according to claim 7, wherein the thickness of the stator yoke is greater than or equal to 60% of the width of the narrowest part of the stator teeth, and less than or equal to 175% of the width of the narrowest part of the stator teeth .
The permanent magnet brushless motor according to claim 1, wherein an air gap is formed between the stator and the rotor, and the average air gap distance of the motor is less than or equal to 0.6% of the outer diameter of the stator.
The permanent magnet brushless motor according to claim 1, wherein the outer diameter of the stator core is less than or equal to 150mm.
The permanent magnet brushless motor according to claim 11, wherein the axial height of the stator core is less than or equal to 25% of the outer diameter of the stator core.
The permanent magnet brushless motor according to any one of claims 1-3, wherein the average radial thickness of the permanent magnets is less than or equal to 20 times the average air gap distance, and greater than or equal to the average air gap distance 4.5 times the gap distance.
The permanent magnet brushless motor according to any one of claims 1-3, wherein the radial thickness of the rotor core is greater than or equal to 50% of the radial thickness of the permanent magnet, and less than or equal to 175% of the radial thickness of the permanent magnet %.
The permanent magnet brushless motor according to claim 1, wherein the motor is a three-phase motor, and the greatest common divisor C of the number of stator teeth/3 and the number of poles of the permanent magnet is greater than or equal to 2 and less than or equal to 8.
The permanent magnet brushless motor according to claim 15, wherein the number of stator teeth/C/3 winding coils are connected in series to form a minimum unit, and the minimum units are connected in series, in parallel, or mixed in series to form any phase of the stator winding.
The permanent magnet brushless motor according to claim 1, wherein the ratio of the number of poles of the permanent magnet to the number of teeth of the stator is greater than or equal to 0.78 and less than or equal to 1.34.
A method of manufacturing a permanent magnet brushless motor as claimed in claim 1, comprising:

Prepare the stator core;

Prepare the winding coil of the stator winding, including:

Use a winding machine to wind the enameled wire on the skeleton to obtain a hollow coil;

Sleeve and fix the hollow coil on the stator core;

Make electrical connections to the coil, including:

The coils of the windings are connected according to the specified connection mode of the windings of the motor.
A multi-axis aircraft, comprising the permanent magnet brushless motor according to any one of claims 1-17.
A robot comprising the permanent magnet brushless motor according to any one of claims 1-17.