Partitioned magnetized light high-reliability brushless motor permanent magnet rotor and forming method thereof

Abstract

The invention provides a partition magnetization light high-reliability brushless motor permanent magnet rotor and a forming method thereof. The forming method comprises the following steps: manufacturing an integral permanent magnet material into a preset shape according to the appearance of the brushless motor rotor; the overall permanent magnet material is divided into a plurality of identical areas in the circumferential direction, each area is magnetized in a partitioned mode through a magnetizer, the magnetizing directions of every two adjacent areas are opposite, and the integrated brushless motor permanent magnet rotor is obtained. According to the invention, the integral magnetization process of partition magnetization is used, the manufacturing process of the motor rotor is simplified, the manufacturing cost is effectively reduced, the weight of the rotor is reduced, and the stability and reliability of the motor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric aviation, and particularly to a partition-magnetized lightweight and highly reliable brushless motor permanent magnet rotor and a forming method thereof. Background Art

[0002] The process of strong magnetic field magnets includes material technology, magnetization technology, surface treatment, etc. Material technology includes material extraction, purification, and forming. Magnetic materials such as common iron, cobalt, nickel, and neodymium iron boron. These material ores will be purified and alloyed by melting, powder metallurgy, casting, extrusion, forging, etc. and formed into shapes such as bars, sheets, and rings to meet different application requirements. Magnetization treatment is to magnetize magnetic materials by applying an external strong magnetic field. Place magnetic materials such as the above-mentioned formed square neodymium iron boron magnetic materials in a strong magnetic field of a powerful electromagnet. By applying current, the electromagnet generates a strong magnetic field. Under the action of this strong magnetic field, the magnetic materials will be magnetized. As Figure 1 shown, this process can reorient the random magnetic domain microstructure inside the neodymium iron boron magnetic material. After magnetization, the previously disordered magnetic domains become ordered. After the external magnetization magnetic field is removed, the neodymium iron boron material still has strong magnetism, making it have stable magnetism and thus becoming a permanent magnet. The surface of the magnet after magnetization is very rough, and the magnet material may be corroded or rusted when exposed to the external environment. Therefore, some surface treatment methods such as electroplating spraying and coating treatment are used to improve its corrosion resistance and appearance. The coating thickness is generally 0.35 mm, and the coating will affect the surface magnetic strength, generally with a 2% - 3% attenuation.

[0003] The traditional magnetization method is to stack all the magnets and then form a magnetization structure with a positive N pole and a negative S pole through a magnetizer. As Figure 2 shown in the overall magnetization method, a large number of magnetic materials are magnetized in batches in an electromagnetic field. All the permanent magnets are magnetized into magnetic sheets with a positive N pole and a negative S pole as a whole.

[0004] Currently, for the manufacture of motor rotors, a non-magnetic metal material cylinder is first prepared as a substrate, then a layer of varnish is coated on the inner wall of the cylinder, and then the permanent magnets are pressed on one by one and bonded well. As Figure 3 shown, the formed rotor structure is as Figures 4 - 8As shown. There are three disadvantages of the rotor made by this process: 1) The bonding process of the permanent magnet will cause radial errors in the height of the rotor. When the motor rotates, these errors cause instability factors. In particular, considering this process error, it is necessary to increase the facing distance between the rotor and the stator. The rotational performance of the motor, such as rotational speed, torque, and interaction force, is inversely proportional to the square of the acting distance between the two magnets. Increasing the facing distance between the electronics and the rotor will greatly affect the efficiency of the motor; 2) The cylindrical substrate increases the weight of the rotor, and thus increases the weight of the entire motor. The main weight sources of the motor are the stator and the rotor. For an aviation motor, reducing the weight of the motor is crucial; 3) The issue of reliability: Since the permanent magnet is bonded to the metal ring substrate, there is a risk of detachment and unreliable factors.

[0005] Low-altitude economy is a hot topic in the world's aviation at present and a historical opportunity for China's aviation development. Low altitude refers to low-altitude transportation within 1,000 meters, and aviation motors are an important pillar industry of the low-altitude economy. At the technical level, aviation motors require light weight. Brushed motors have many disadvantages, mainly including large volume, poor reliability, and very low power-to-weight ratio, which cannot meet the technical requirements of new energy transportation and new energy aviation. Brushless motors are the first choice for aviation motors. Brushless motors are the most advanced technology of motors and will completely replace brushed motors in the near future. In fact, the patent for brushless motors was proposed in the 1950s (the earliest inventors of brushless motors: A.E. Thomas, etc., Brushless DC motor with permanent magnet rotor, 1960-10-07, (1959), https: / / patents.google.com / patent / US3096467A / en). And in the following 20 years, a series of updates were made to the physical configuration and its control unit (R.K. Hill, Brushless direct current motor, (1962), https: / / patents.google.com / patent / US3364407; E.W. Manteuffel etc., Solid-state commutator direct current motor employing hall effect elements, (1965)https: / / patents.google.com / patent / US3165685A; J. Brunner, etc., Brushless direct-current motor, (1967), https: / / patents.google.com / patent / US3486099A, Rolf Muller, Brushless d-c motor, (1973), https: / / patents.google.com / patent / US3891905A / en), but none of them have been widely used.The reason why brushless motors have not been widely used is mainly that the technical threshold of the motor control circuit is too high. A complex high-power electronic control system is required for effective operation. Before the advent of integrated circuits, the cost was extremely high and it was not easy to manufacture. Therefore, there was a lag in brushless motor technology. It was not until the late 1980s that there was a breakthrough in integrated circuit technology. The emergence of high-power integrated circuits helped brushless motors to be widely used and gradually accepted in the industrial and aviation fields. (The last inventor (integrator) of the brushless motor: Michael John Werson, Brushless DC motors, (1996) https: / / patents.google.com / patent / US5986376A / en, is a configuration combination type of a complete brushless motor for use in electric vehicles). In addition, the discovery of neodymium iron boron permanent magnets in the 1980s promoted the widespread application of brushless motors. China is the only major country rich in neodymium iron boron rare earth materials, which greatly reduces the manufacturing cost of brushless motors and enables their practical application.

[0006] After retrieval, it was found that the Chinese invention patent with the application publication number CN102171908A discloses a magnet body for a field pole, a manufacturing method of the magnet body for the field pole, and a permanent magnet type rotating electric machine. The magnet body is disposed on the rotor or stator of the permanent magnet type rotating electric machine and has: a plurality of magnet pieces formed by breaking and dividing a single permanent magnet, and one or more magnet piece holding members for holding the magnet pieces. This patent is for suppressing heat generation. The fractured surfaces of the divided parts are aligned using an adhesive tape, and the four sides perpendicular to the fractured surface are covered with a tubular heat shrinkable rubber, which is shrunk at a temperature of 100 °C or higher to be in close contact with the magnet, and the process is rather cumbersome. The Chinese invention patent with the application publication number CN106257298A discloses a magnetic field generating body, a magnetic sensor system, and a magnetic sensor. The magnetic field generating body includes a plurality of magnetic field generating portions arranged in a specified pattern and generating a plurality of external magnetic fields. Each of the plurality of magnetic field generating portions includes a first ferromagnetic body portion and a first antiferromagnetic body portion. The first antiferromagnetic body portion is in contact with the first ferromagnetic body portion and exchanges coupling with the first ferromagnetic body portion. The first ferromagnetic body portion has magnetization. Among the plurality of magnetic field generating portions, there are two magnetic field generating portions in which the directions of magnetization of the first ferromagnetic body portions are different from each other. This patent is applied to a magnetic sensor system and pays more attention to the influence of measurement errors generated by the magnetic field generating portions formed in such a form that the directions of the main components of the bias magnetic field are opposite to each other. Neither of the above patents can be applied to the motor rotor. Summary of the Invention

[0007] Aiming at the defects in the prior art, the purpose of the present invention is to provide a partitioned magnetization lightweight and highly reliable brushless motor permanent magnet rotor and its forming method.

[0008] According to a first aspect of the present invention, there is provided a forming method for a partition-magnetized lightweight and highly reliable brushless motor permanent magnet rotor, including:

[0009] Manufacture an integral permanent magnet material into a preset shape according to the shape of the brushless motor rotor;

[0010] Divide the integral permanent magnet material into a plurality of identical regions along the circumferential direction, and use a magnetizer to magnetize each region separately. The magnetization directions of two adjacent regions are opposite to obtain an integral brushless motor permanent magnet rotor.

[0011] Optionally, in the step of manufacturing the integral permanent magnet material into a preset shape according to the shape of the brushless motor rotor: for a radial brushless motor rotor, the integral permanent magnet material is made into a cylindrical shape.

[0012] Optionally, in the step of manufacturing the integral permanent magnet material into a preset shape according to the shape of the brushless motor rotor: for an axial brushless motor rotor, the integral permanent magnet material is made into a disc shape.

[0013] Optionally, the step of using a magnetizer to magnetize each region separately includes: magnetizing the first region according to the requirements of the magnetization magnetic field direction, then rotating the integral permanent magnet material successively along the circumferential direction, aligning the magnetizer to the next region, and after alignment, changing the magnetization magnetic field direction to magnetize the second region, and so on, to complete the staggered magnetization of multiple regions to form an integral permanent magnet motor rotor.

[0014] Optionally, the angle of successive rotation of the integral permanent magnet material is determined according to the number of divided regions.

[0015] Optionally, the integral permanent magnet material is divided into 4 to 24 identical regions.

[0016] Optionally, the integral permanent magnet material is a neodymium iron boron permanent magnet.

[0017] According to a second aspect of the present invention, there is provided a partition-magnetized lightweight and highly reliable brushless motor permanent magnet rotor, which is manufactured by using the above-mentioned forming method for a partition-magnetized lightweight and highly reliable brushless motor permanent magnet rotor.

[0018] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0019] 1. The method for manufacturing a brushless motor rotor with zoned magnetization according to the present invention uses an integral permanent magnet material to form a single piece. It only requires directly shaping the integral permanent magnet material into the shape of the motor rotor, and then using zoned magnetization to magnetize the permanent magnet material into a permanent magnet rotor structure with alternating N and S poles in different regions, forming a permanent magnet motor rotor. Using the integral magnetization process eliminates the cost of manufacturing the substrate material and the additional process steps of pasting, and does not require any bonding process, simplifies the manufacturing process of the motor rotor, and effectively reduces the manufacturing cost.

[0020] 2. The present invention directly shapes the permanent magnet material into the shape of the motor without using a support structure. Compared with the motor rotor with a support in the prior art, it reduces at least half of the weight, and thus is more suitable for an aeroengine.

[0021] 3. The brushless motor rotor provided by the present invention is an integrated permanent magnet rotor with an integrated structure, which can ignore the error redundancy in the traditional rotor process, reduce the designed distance between the stator and the rotor by at least one millimeter, and can improve the motor performance by at least twice. The improvement effect of the motor performance is very significant.

[0022] 4. The integral magnetization process provided by the present invention does not need to consider the error of the adhesion process flow. The integral magnetization process can magnetize a whole magnet. The magnetic field intensity per unit mass of the permanent magnet motor rotor magnetized in this way is stronger, the rotating magnetic flux is more uniform, the mechanical stability of the motor rotation is better, and there is no problem of magnet detachment during rotation, so the reliability is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, purposes and advantages of the present invention will become more obvious by reading the detailed description of the non - restrictive embodiments with reference to the following drawings:

[0024] Figure 1 It is a schematic diagram of the principle of permanent magnet magnetization in the background technology;

[0025] Figure 2 It is a schematic diagram of the batch magnetization process in the background technology;

[0026] Figure 3 It is a schematic diagram of the manufacturing process of a brushless motor rotor in the background technology;

[0027] Figure 4 It is a schematic diagram of the structure of a brushless motor rotor in the background technology;

[0028] Figure 5 It is a schematic diagram of the structure of a brushless motor radial rotor in the background technology Figure 1 ;

[0029] Figure 6 It is a schematic diagram of the structure of a brushless motor radial rotor in the background technology Figure 2 ;

[0030] Figure 7 The structure of the axial rotor of the brushless motor in the background technology is shown in FIG. Figure 1 ;

[0031] Figure 8 The structure of the axial rotor of the brushless motor in the background technology is shown in FIG. Figure 2 ;

[0032] Figure 9 It is a schematic diagram of the principle of zoned magnetization in one embodiment of the present invention;

[0033] Figure 10 A schematic diagram of zoned magnetization in one embodiment of the present invention;

[0034] Figure 11 The structure of the brushless electronic rotor in one embodiment of the present invention is shown in FIG. Figure 1 ;

[0035] Figure 12 The structure of the brushless electronic rotor in one embodiment of the present invention is shown in FIG. Figure 2 ;

[0036] Figure 13 A schematic diagram of zoned magnetization in one embodiment of the present invention;

[0037] Figure 14 It is a schematic diagram of the structure of a brushless electronic rotor in one embodiment of the present invention;

[0038] Figure 15 is the variation of magnetic field intensity on the rotor surface with distance;

[0039] Figure 16 is the variation of magnetic field intensity on rotor surface with thickness;

[0040] Figure 17 It is the surface strength of the magnet with partitioned magnetization in the embodiment of the present invention. DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0042] The partition magnetization method is as follows Figure 9As shown, the whole magnet is divided into sections and magnetized as needed. The magnet material is magnetized in sections by the magnetizer in the order of successive upward movement, forming permanent magnets with different NS pole magnetic circuit structures, and the adjacent areas present reverse polarity magnetic fields. Using this magnetization technology, the whole magnet can be divided into sections and magnetized into different magnetic circuit structures according to actual needs.

[0043] A method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor provided by an embodiment of the present invention comprises: manufacturing an integral permanent magnet material into a preset shape according to the shape of the brushless motor rotor; dividing the integral permanent magnet material of the preset shape into a plurality of identical regions along the circumferential direction, and performing partitioned magnetization on each region by using a magnetizer, wherein the magnetization directions of two adjacent regions are opposite, thereby obtaining an integrated permanent magnet rotor for the brushless motor.

[0044] Reference Figure 10 In some embodiments, for a radial brushless motor rotor, the integral permanent magnet material is made into a cylindrical shape. The first region is magnetized according to the magnetizing magnetic field direction requirement, and the magnetizing direction is SN or NS. Then the integral permanent magnet material is rotated successively along the circumferential direction, and the magnetizer is aligned to the next region, that is, the center of the region to be magnetized. After alignment, the magnetizing magnetic field direction is changed, and the second region is magnetized. And so on, the staggered magnetization of multiple regions is completed to form an integrated permanent magnet motor rotor.

[0045] In some embodiments, the angle of successive rotation of the whole permanent magnet material is determined according to the number of divided regions. The whole permanent magnet material is rotated by mechanical transmission, and the rotation angle can be adjusted and controlled by a stepping motor.

[0046] In some embodiments, the integral permanent magnet material is a neodymium iron boron permanent magnet. In other embodiments, other permanent magnet materials may also be used according to actual needs.

[0047] In a specific embodiment, the overall manufacturing process of the radial brushless motor rotor partition magnetization is as follows:

[0048] like Figure 10 As shown, according to the size of the motor rotor, such as the diameter and length of the cylinder, the thickness of the cylinder, etc., neodymium iron boron or other strong magnetic permanent magnet materials are made into the designed motor rotor shape through casting and lathe processing, and then different areas of the cylinder are magnetized by a magnetizer.

[0049] The permanent magnets of the brushless radial motor rotor are placed with N poles and S poles staggered and evenly arranged along the circumference. Depending on the design of the motor, the number of permanent magnet areas is not fixed. For example, the entire permanent magnet material is divided into 4 to 24 identical areas.

[0050] For example, in the motor design, the motor rotor has 8 permanent magnets, that is, it needs to be magnetized into 8 regions. The process of magnetizing using a permanent magnet machine is to first magnetize the first region according to the NS pole requirement of magnetization, and then align the magnetizer to the next region according to the circular rotation. After alignment, change the magnetization magnetic field direction to SN, and magnetize the second region of the permanent magnet. And so on, complete the staggered magnetization of the entire circumference of the 8 regions to form an integrated permanent magnet motor rotor. If the rotor of the motor includes 4 or 16 permanent magnet regions, the angle of the magnet's circular rotation can be adjusted accordingly to achieve the partitioned magnetization task of the entire circumference.

[0051] In the conventional brushless motor rotor, individual permanent magnets are glued to the substrate material piece by piece and staggered. In the embodiment of the present invention, the whole permanent magnet material is directly made into a cylindrical shape, and then the cylindrical shape is placed on a magnetizer for direct magnetization to form a Figure 11 and Figure 12 The rotor structure shown.

[0052] In some embodiments, for an axial brushless motor rotor, a solid permanent magnet material is fabricated into a disc shape.

[0053] The overall manufacturing process of the partitioned magnetization of the axial motor rotor is as follows:

[0054] like Figure 13 As shown in the figure, according to the design size of the motor rotor, such as the diameter and thickness of the disc, the NdFeB or other strong magnetic permanent magnet materials are made into the designed motor rotor shape through casting and lathe processing, and then the magnetizer is used to magnetize different areas of the disc. The permanent magnets on the brushless axial motor rotor are placed with N poles and S poles staggered and evenly arranged along the circumference. Depending on the design of the motor, the number of permanent magnet areas is not fixed, and is generally 4 to 24.

[0055] For example, in the motor design, the motor rotor has 8 permanent magnets, that is, it needs to be magnetized into 8 areas. The process of magnetizing using a permanent magnet machine is to first magnetize the first area according to the NS pole of the magnetization, and then align the magnetizer to the next area according to the circular rotation. After alignment, the magnetic field direction of the magnetization is changed to SN to magnetize the second area with the magnet, and so on, to complete the staggered magnetization of the entire circumference of the 8 areas to form an integrated permanent magnet motor rotor. The overall structure formed is as follows Figure 14 If the rotor of the motor includes 4 or 16 permanent magnet regions, the angle of the permanent magnet's circumferential rotation can be adjusted accordingly to achieve the task of partitioned magnetization of the entire circumference.

[0056] According to the method in the above embodiment of the present invention, the integrated permanent magnet material such as NdFeB is magnetized into different magnetic poles according to different regions, so as to form an integrated partitioned magnetized radial and axial motor rotor. Compared with the attached permanent magnet rotor currently formed by adhering NdFeB (neodymium iron boron) permanent magnets to a substrate, the thickness of the integrated permanent magnet rotor in the embodiment of the present invention is reduced by half, and no bonding synthesis steps are required.

[0057] The prior art attaches different magnets to a base to form an integral rotor. The above embodiment of the present invention uses a partitioned magnetization method to construct an integrated lightweight, efficient, and highly reliable permanent magnet rotor for a brushless motor, and its advantages are reflected in the following aspects:

[0058] (1) Simplify the manufacturing process of motor rotor and reduce costs

[0059] The original motor rotor process first magnetizes the sheet magnets into permanent magnets, and then adheres the magnetized magnets to a substrate. This technical process has many steps and has problems such as complex process and high material cost.

[0060] By using the integral magnetization process in the embodiment of the present invention, it is only necessary to directly make the permanent magnet into the shape of the motor rotor, and then perform zone magnetization to form a permanent magnet motor rotor in one piece. The integral magnetization process enables the permanent magnet rotor to be formed in one piece, thereby eliminating the cost of making substrate materials and the additional process step of pasting. It is only necessary to simply install the integrated permanent magnet rotor on the motor, which can effectively reduce the manufacturing cost and simplify the manufacturing process of the motor rotor.

[0061] (2) Reduce the weight of the motor

[0062] In conventional brushless motor designs, the rotor permanent magnets are attached to a cylindrical substrate for supporting keys. The cylindrical substrate increases the weight of the rotor, which also increases the weight of the entire motor. The above-mentioned embodiment of the present invention removes this support and directly makes the permanent magnet material into a cylinder, that is, the permanent magnet material itself is used as the cylindrical substrate, and the permanent magnet is magnetized in different regions into a permanent magnet rotor structure with alternating N poles and S poles by using a zoned magnetization method to form a motor rotor. Compared with a rotor with a support, the weight of the rotor can be reduced by at least half.

[0063] It should be noted that "half" is a relative error. The main sources of weight of the motor are the stator and the rotor. For aviation motors, it is more important to reduce the absolute value of the motor weight. Reducing the weight of the rotor is very important for aviation. What is important is the absolute error, that is, the absolute weight. For example, the diameter of the cylindrical substrate is 300 mm, the length is 300 mm, the thickness is 30 mm, the thickness of the permanent magnet is also 30 mm, and the specific gravity of the material is 8 grams per cubic centimeter. After calculation, the weight of the rotor made with the existing process is 129.6 kg. If the substrate material is omitted and the permanent magnet is used directly as the substrate rotor, then the weight of the rotor is 64.8 kg. There is a very obvious difference in weight between the two. The reduction in the weight of the rotor is very important for aircraft engines and will have a great impact on aviation power.

[0064] The above-mentioned embodiments of the present invention optimize the power-to-weight ratio of the brushless motor, that is, the weight is reduced under the same power output, and the manufactured brushless motor is particularly suitable for electric aviation transportation.

[0065] (3) Improve motor efficiency

[0066] In the traditional motor rotor manufacturing process, the permanent magnets are bonded to the rotor substrate in sequence. The bonding process will cause radial errors in the height of the rotor. Considering this process error, the distance between the rotor and the stator must be increased to avoid failures caused by the distance between the two being too small during rotation. However, increasing the distance will greatly attenuate the magnetic field strength. Experiments show that the magnetic field strength attenuates inversely with the distance, such as Figure 15 As shown in the figure (B is the magnetic field strength in mT; H is the distance from the permanent magnet in mm), the surface magnetic field strength is 600mT. If the distance increases by 1mm, the magnetic field strength decays to 450mT. In brushless motors, the distance between the electrons and the rotor is only three to five millimeters, so reducing the distance between the rotor and the stator in the motor design will greatly improve the working efficiency of the motor. The motor's rotational performance, such as speed, torque, and interaction force, is in a square relationship with the magnetic field strength. Reducing the distance between the stator and the rotor will significantly improve the motor's efficiency.

[0067] The integrated permanent magnet rotor in the above embodiment of the present invention is an integrated structure, which can ignore the error redundancy in the traditional rotor process. In the motor design, the distance between the rotor and the stator can be greatly reduced, and the design distance between the stator and the rotor can be reduced by at least one millimeter. Preliminary experimental estimates show that according to Figure 15If the distance between the stator and the rotor is reduced by one millimeter, the magnetic field strength increases from 450mT to 600mT. The magnetic field force of the two magnets is in a square relationship with the magnetic field strength, so the magnetic force increases by nearly one-fold (600^2 / 450^2=1.78), which can double the motor performance. The effect is very significant. Therefore, the integrated permanent magnet rotor in the embodiment of the present invention can greatly improve the working efficiency of the motor.

[0068] (4) Improve motor reliability and stability

[0069] Traditional integrated permanent magnet rotors adhere different magnetized magnets to the substrate, which will cause two hidden dangers: 1) During the adhesion process, the height and direction of the magnets may be inconsistent. During high-speed operation, these small errors may cause the motor to vibrate, thereby affecting the reliability and efficiency of the motor. 2) Once these permanent magnet plates fail and fall off, they will cause safety hazards.

[0070] The overall magnetization process in the above embodiment of the present invention does not need to consider the error of the adhesion process flow. The overall magnetization process can magnetize a whole magnet. The magnets magnetized in this way are more evenly distributed, the rotating magnetic flux is more uniform, the motor has better mechanical stability, and is more stable during operation. In the embodiment of the present invention, the integrally formed permanent magnet motor rotor itself is a whole, not an assembly. There is no problem of magnets falling off during rotation and other scattered parts, and the reliability will be greatly improved. The rotor integration process method proposed in the embodiment of the present invention can greatly improve the reliability of the motor and improve the mechanical stability of the motor.

[0071] The above-mentioned embodiments of the present invention are of special significance to aircraft engines. The low-altitude economy requires low-altitude aircraft, low-altitude aircraft require electric aircraft engines, and electric aircraft engines rely on aircraft motors. Therefore, aircraft motors are an important pillar industry of the low-altitude economy, and the technical focus of aircraft motors is light weight, high torque, and high reliability. The embodiments of the present invention just meet the requirements of these three key points: 1) Optimize and improve the power-to-weight ratio of brushless motors. For example, the weight of the rotor can be reduced by half. 2) Improve the motor torque. Compared with land transportation power and marine transportation power, aircraft motors require greater torque, and the torque is proportional to the square of the magnetic field strength. As mentioned above, the weight of the rotor is reduced by half. If the thickness of the permanent magnet is doubled, that is, if the cylindrical rotor substrate is also replaced with permanent magnet material, then the thickness of the permanent magnet is doubled while the weight does not change. Figure 16As shown, the permanent magnet is thickened from 4 mm to 8 mm, the magnetic field strength is doubled, and the torque will be increased by four times. That is, the method in the embodiment of the present invention can achieve nearly four times the motor torque with a rotor of the same weight. 3) Improve reliability. For aviation, high reliability is very important. Since the rotor magnet bonding process is omitted in the embodiment of the present invention, the risk of detachment is avoided, and the integrated permanent magnet rotor greatly improves the reliability.

[0072] Figure 17 is the surface strength of the magnet with zoned magnetization measured actually. It can be seen that within a very small area, a magnetic isolation area with very high precision of N pole and S pole can be formed. Figure 17 It proves the feasibility of the zoned magnetization technology of the present application, and a magnetic isolation area with very high precision of N pole and S pole can be realized, with a precision of up to 0.35 mm. Compared with the conventional method of bonding N pole and S pole magnets on the rotor ring (the precision is in the order of millimeters), it has higher precision. When the integrated permanent magnet rotor forms multiple magnetic poles through zoned magnetization and is applied to a permanent magnet motor, the influence caused by the error (about 0.35 mm) of the main component of the bias magnetic field of two adjacent north and south magnetic poles can be ignored.

[0073] Another embodiment of the present invention provides a permanent magnet rotor for a brushless motor, which is manufactured by using the zoned magnetization manufacturing method of the brushless motor rotor described above.

[0074] Due to the technical effects of the embodiment of the zoned magnetization manufacturing method of the brushless motor rotor, the above embodiment of the brushless motor rotor also has the same technical effects, which will not be elaborated in detail here.

[0075] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various deformations or modifications within the scope of the claims, which do not affect the essence of the present invention. The above preferred features can be combined arbitrarily without conflict.

Claims

1. A method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor, characterized in that: include: According to the shape of the brushless motor rotor, the whole permanent magnet material is made into a preset shape; The integral permanent magnet material is divided into a plurality of identical regions along the circumferential direction, and each region is magnetized by a magnetizer, and the magnetization directions of two adjacent regions are opposite, so as to obtain an integral permanent magnet rotor of a brushless motor.

2. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The whole permanent magnet material is made into a preset shape according to the shape of the brushless motor rotor, wherein: for the radial brushless motor rotor, the whole permanent magnet material is made into a cylindrical shape.

3. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The whole permanent magnet material is made into a preset shape according to the shape of the brushless motor rotor, wherein: for the axial brushless motor rotor, the whole permanent magnet material is made into a disc shape.

4. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The method of using a magnetizer to magnetize each area separately includes: magnetizing the first area according to the magnetic field direction requirement of magnetization, then rotating the entire permanent magnet material in a circumferential direction, aligning the magnetizer to the next area, and after alignment, changing the magnetization magnetic field direction, magnetizing the second area, and so on, completing the staggered magnetization of multiple areas to form an integrated permanent magnet motor rotor.

5. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The angles at which the integral permanent magnet material rotates successively are determined according to the number of divided regions.

6. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The whole permanent magnet material is divided into 4 to 24 identical regions.

7. The method for forming a partitioned magnetized lightweight and highly reliable permanent magnet rotor for a brushless motor according to claim 1, characterized in that: The integral permanent magnet material is a neodymium iron boron permanent magnet.

8. A partitioned magnetized lightweight high-reliability brushless motor permanent magnet rotor, characterized in that: The invention is manufactured by using the molding method of the partitioned magnetization lightweight and high-reliability brushless motor permanent magnet rotor as described in any one of claims 1 to 7.

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