Magnetic steel body, magnetic steel and manufacturing method therefor, and motor

Abstract

Embodiments of the present application provide a magnetic steel body, magnetic steel and a manufacturing method therefor, and a motor. The magnetic steel body comprises a comb back and a plurality of comb teeth, the comb teeth are arranged at intervals along the length direction, a row of comb teeth is provided at both ends of the comb back along the width direction, tooth grooves are formed between adjacent comb teeth, and the comb teeth and the comb back are integrally processed. The magnetic steel comprises the magnetic steel body and filling portions, and the tooth grooves are filled with the filling portions. According to the magnetic steel body provided in the embodiments of the present application, by locally cutting and processing the tooth grooves, the processing steps and processing time of the magnetic steel body, and material waste caused by cutting are reduced. By performing heavy rare earth grain boundary diffusion treatment on the comb teeth of the magnetic steel body, the use of heavy rare earth is reduced, and the yield rate of the magnetic steel body is improved. According to the magnetic steel provided in the embodiments of the present application, by filling the tooth grooves of the magnetic steel body with the filling portions, the eddy current loss in the comb teeth of the magnetic steel is reduced, the overall working temperature of the magnetic steel is reduced, and the performance of the magnetic steel is improved.

Description

Magnetic steel body, magnetic steel, manufacturing method thereof, and motor

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202311190235.7 and application date September 14, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of power generation, and in particular to a magnetic steel body, a magnetic steel, a manufacturing method thereof, and a motor. Background Art

[0004] A permanent magnet motor (PMM) uses permanent magnets to generate a magnetic field. When a frequency converter controls a PMM motor, high-order time harmonics are generated in the motor's stator windings. These high-order harmonic magnetic fields induce eddy currents in the magnets, causing them to heat up and lead to magnetic flux loss. Suppressing these eddy currents is crucial for improving motor efficiency, reducing temperature rise, enhancing dynamic response, and reducing cooling requirements, ultimately enhancing motor performance, reliability, and lifespan.

[0005] The magnets of related motors generally adopt a rectangular design. The sintered magnet body is cut into independent segments through processing, and then the segments are bonded with high-temperature resistant and high-strength glue. After bonding, the magnet needs to be processed again to ensure the overall size. The processing steps are many and the processing is difficult, which leads to a significant increase in the processing cost of the magnet.

[0006] Summary of the Invention

[0007] In view of this, the embodiments of the present application hope to provide a magnetic steel body, a magnetic steel and a manufacturing method thereof, and a motor, so as to reduce the manufacturing cost of the magnetic steel and improve the yield rate of the magnetic steel.

[0008] To achieve the above objectives, one aspect of an embodiment of the present application provides a magnetic steel body comprising a comb back and a plurality of comb teeth spaced apart along the length direction, with a row of the comb teeth disposed at each end of the comb back along the width direction, and tooth grooves formed between adjacent comb teeth. The comb teeth and the comb back are integrally formed.

[0009] In some embodiments, the depth of the tooth groove is greater than one tenth of the width of the magnetic steel body and less than nine tenths of the width of the magnetic steel body.

[0010] In some embodiments, the direction of the tooth groove is parallel to the width direction or forms an angle with the width direction.

[0011] Another aspect of the embodiments of the present application provides a magnetic steel, comprising the magnetic steel body described in any embodiment of the present application and a filling portion, wherein the filling portion is filled in the tooth groove to enhance the insulation performance between adjacent comb teeth.

[0012] In some embodiments, the comb teeth are infiltrated with heavy rare earth.

[0013] In some embodiments, the filling portion is insulating glue.

[0014] Another aspect of the present invention provides a method for manufacturing a magnetic steel, comprising:

[0015] The magnetic steel body is cut and processed to form a structure having a comb back, comb teeth and tooth grooves;

[0016] performing a heavy rare earth grain boundary diffusion treatment on the magnetic steel body;

[0017] Filling portions are formed between the tooth grooves.

[0018] In some embodiments, the step of performing a grain boundary diffusion treatment of heavy rare earth on the magnetic steel body is specifically performing a grain boundary penetration treatment of heavy rare earth on the magnetic steel body.

[0019] In some embodiments, the step of performing a grain boundary diffusion treatment of heavy rare earth on the magnetic steel body specifically includes:

[0020] The grain boundary diffusion of heavy rare earth is performed only on the comb teeth, so that the magnetic steel body is partially provided with heavy rare earth.

[0021] In some embodiments, the step of forming a filling portion between the tooth grooves specifically includes:

[0022] The magnetic steel body is subjected to an impregnation process to form filling portions between the tooth grooves.

[0023] In some embodiments, the distribution of eddy current losses in the width direction of the magnetic steel body is analyzed to provide a basis for calculating the processing depth of the tooth groove.

[0024] Another aspect of the embodiments of the present application provides a motor, comprising an iron core and the magnetic steel described in any embodiment of the present application, wherein the magnetic steel is arranged on the iron core.

[0025] The magnetic body provided in the embodiments of the present application utilizes localized cutting to form tooth grooves, replacing the complete cutting method used in related technologies. This reduces the number of processing steps, processing time, and material waste associated with cutting. Furthermore, the reduced volume of the comb teeth of the magnetic body facilitates grain boundary diffusion of heavy rare earth elements, improving the manufacturing efficiency of the magnetic body and thereby reducing its processing costs.

[0026] The magnet provided in the embodiment of the present application fills the tooth grooves with the filling part, and the magnet body and the filling part constitute an integrated magnet. There is no need to bond independently segmented magnet bodies, which reduces the difficulty of bonding between the magnet bodies after cutting, thereby reducing the processing cost of the magnet body.

[0027] The manufacturing method of the magnetic steel provided in the embodiment of the present application is applied to the magnetic steel in any embodiment of the present application. By adding a filling portion in the tooth groove of the magnetic steel body, the local insulation performance of the magnetic steel is improved, thereby reducing the local eddy current loss of the magnetic steel and lowering the operating temperature of the magnetic steel. By performing a grain boundary diffusion treatment of heavy rare earth on the comb tooth part of the magnetic steel body structure, the local magnetic field strength is improved. After reducing the eddy current loss of the magnetic steel, the temperature of the magnetic steel is reduced and the magnetism is stronger. The comb back does not need to be infiltrated with heavy rare earth, which reduces the application of heavy rare earth and saves costs.

[0028] An embodiment of the present application provides a motor, comprising an iron core and the magnetic steel of any embodiment of the present application. By reducing the eddy current loss of the magnetic steel, the magnetic flux utilization rate of the magnetic steel in the motor is improved, thereby improving the performance, reliability and life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a three-view diagram of a magnetic steel structure according to some embodiments of the present application;

[0030] FIG2 is a schematic diagram of the three-dimensional structure of a magnetic steel body according to some embodiments of the present application;

[0031] FIG3 is a schematic diagram of a magnetic steel structure according to some embodiments of the present application;

[0032] FIG4 is a schematic diagram of the assembly of the magnetic steel and the iron core in some embodiments of the present application;

[0033] FIG5 is a schematic diagram showing the distribution of eddy current loss in the width direction of the magnetic steel in some embodiments of the present application;

[0034] FIG6 is a schematic diagram showing the distribution of peak eddy current loss in the width direction of the magnetic steel in some embodiments of the present application;

[0035] FIG7 is a schematic flow chart of a method for manufacturing magnetic steel in some embodiments of the present application. DETAILED DESCRIPTION

[0036] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] In the description of the embodiments of this application, it should be noted that the magnets are typically designed in a rectangular, trapezoidal, or tile-like shape and are mounted on the rotor core or stator core of a motor. The upper and lower surfaces of the magnets align with the upper and lower surfaces of the magnet slots in the core. The distance between the upper and lower surfaces of the magnets is referred to as the thickness or height of the magnets, and the depth of the magnets within the magnet slots along the axial direction of the core is referred to as the length of the magnets. Terms such as "width direction," "length direction," and "height direction" indicate orientations or positional relationships based on the orientations or positional relationships shown in FIG1 .

[0038] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0039] In the description of the embodiments of the present application, it should be noted that, unless otherwise specified, “multiple” and “multiple” refer to two or more, and two or more, respectively.

[0040] When the magnets in a permanent magnet motor are subjected to high-harmonic magnetic fields, they induce eddy currents, or induced currents. These induced currents increase the magnet temperature, leading to magnetic flux loss and thus reducing the motor's output torque and efficiency. Suppressing these eddy current losses in the magnets helps improve motor performance, reliability, and lifespan.

[0041] In related motors, the magnetic steel structure often adopts a rectangular cross-section design. The sintered magnetic steel body is divided into segments through machining, and then bonded with a high-temperature resistant, high-strength adhesive. After bonding, the magnetic steel is processed to ensure the overall size of the magnetic steel, thereby reducing the eddy current loss of the magnetic steel. The segmentation and bonding technology significantly increases the cost of magnetic steel processing, accounting for more than 40% of the total cost. The additional processing steps lead to longer lead times for magnetic steel. At the same time, the processing results in waste of magnetic steel materials, resulting in low material utilization.

[0042] Based on the above, a first aspect of the present invention provides a magnetic body. Referring to Figures 1 and 2 , the magnetic body 12 includes a comb back 121 and a plurality of comb teeth 122 , with tooth grooves 12a between adjacent comb teeth 122 . The comb teeth 122 are spaced apart along the length, and a row of comb teeth 122 is provided at each end of the comb back 121 along the width direction. The comb teeth 122 and comb back 121 are integrally machined to form a comb-like structure.

[0043] It should be noted that the cross-section of the magnetic body 12 may be rectangular or trapezoidal. In some embodiments of the present application, the cross-section of the magnetic body 12 is trapezoidal.

[0044] It should be noted that the comb teeth 122 and the comb back 121 are integrally processed to form a comb-shaped magnetic body 12, and the partial cutting replaces the complete cutting of the magnetic body in the related art, which reduces the cutting waste of the magnetic body 12 during processing and reduces the cost of magnetic steel materials in the manufacturing process.

[0045] In the related art, when bonding the cut magnets together, a mold is required to standardize the overall shape of the bonded magnets. In the embodiment of the present application, the magnet body 12 is a comb-shaped structure formed by integral machining. There is no need to bond the cut magnet bodies together; only the insulating adhesive needs to be filled into the tooth grooves 12a. This reduces the difficulty of bonding the magnet bodies together in the related art and reduces the processing cost of the magnet body 12.

[0046] Furthermore, in the related art, after bonding the independently segmented magnetic bodies, the bonded magnetic bodies need to be processed for external dimensions. However, in the embodiment of the present application, the magnetic body 12 is not cut into independent small segments. After the magnetic body 12 is combined with the filling portion 11, no overall processing is required, which reduces the number of processing steps, reduces processing costs, and improves the manufacturing efficiency of the magnetic body.

[0047] It should be noted that the direction of the tooth groove 12a can be parallel to the width direction of the magnetic body 12, or can form a certain angle with the width direction of the magnetic body 12. The tooth groove 12a formed by processing can reduce the volume at both ends of the magnetic body 12, facilitate the subsequent grain boundary diffusion treatment of heavy rare earth, and improve the performance of the magnetic body 12. The shape and width of the tooth groove 12a are not limited here.

[0048] It is understood that the depths of the tooth grooves 12a at both ends of the magnetic body 12 along the width direction can be the same or different. In some embodiments of the present application, the depths of the tooth grooves 12a at the left and right ends of the magnetic body 12 are the same, for example, one-quarter of the width of the magnetic body 12.

[0049] Another aspect of the embodiments of the present application provides a magnetic steel 10 , as shown in FIG. 2 and FIG. 3 , including a magnetic steel body 12 and a filling portion 11 of any embodiment of the present application, wherein the filling portion 11 is filled in the tooth groove 12 a of the magnetic steel body 12 .

[0050] It should be noted that the filling portion 11 within the tooth groove 12a can increase the resistance between the multiple comb teeth 122, enhancing the insulation performance between the multiple comb teeth 122, while maintaining the overall strength of the magnetic steel 10. The staggered arrangement of the comb teeth 122 and the filling portion 11 reduces the eddy current loss of the magnetic steel 10 in the comb teeth 122 portion, thereby lowering the overall operating temperature of the magnetic steel 10.

[0051] For example, the filling portion 11 may be an insulating adhesive. The filling portion 11 is formed in the tooth groove 12a by a dipping process or a brushing process.

[0052] It should be noted that, to improve the demagnetization resistance of the magnetic steel 10, in some embodiments of the present application, the magnetic steel body 12 may be treated with a grain boundary diffusion of heavy rare earth elements to increase the magnetic field strength of the magnetic steel body 12. In other embodiments of the present application, the grain boundary diffusion of heavy rare earth elements is performed only on the comb teeth 122 of the magnetic steel 10, where demagnetization is more severe, while the comb back 121 does not require such treatment. Performing the heavy rare earth diffusion treatment only on the comb teeth 122 reduces the amount of heavy rare earth elements used, thereby lowering the manufacturing cost of the magnetic steel 10.

[0053] Another aspect of the present invention provides a method for manufacturing a magnetic steel, which can be applied to the magnetic steel 10 of any embodiment of the present invention. Referring to FIG. 7 , the manufacturing method includes:

[0054] Step S1, cutting the magnetic steel body to form a comb-like structure having a comb back, comb teeth and tooth grooves;

[0055] Step S2, performing a heavy rare earth grain boundary diffusion treatment on the magnetic steel body;

[0056] Step S3: forming a filling portion between the tooth grooves.

[0057] It should be noted that in step S1, the comb teeth 122 and the comb back 121 are integrally formed, which can be achieved by cutting the two ends of the magnetic steel body 12 to cut out the tooth grooves 12a to form the comb teeth 122, or by other integrally formed methods, which are not limited here.

[0058] It is understandable that the cutting process may be wire cutting, laser cutting or other cutting methods. In the embodiment of the present application, the cutting process is wire cutting.

[0059] It should be noted that in step S1, in order to determine the processing depth of the tooth groove 12a in the width direction of the magnetic steel body 12, it is necessary to calculate and analyze the distribution of eddy current loss in the width direction of the magnetic steel body, and perform tooth groove cutting on the part with severe eddy current loss in the analysis results, thereby reducing the eddy current loss of the magnetic steel, lowering the operating temperature of the magnetic steel, reducing the magnetic flux loss caused by high temperature, and improving the output parameters of the motor.

[0060] Please refer to Figure 5. In some embodiments, Figure 5 is a schematic diagram of the eddy current loss in the width direction of the magnetic body obtained after calculation and analysis. In the line graph of Figure 5, the vertical axis of the line graph is the eddy current loss in watts, which can be converted into energy consumed per second. The horizontal axis of the line graph is the width of the magnetic body, which corresponds to the position of the width of the magnetic body above the line graph. It can be seen from Figure 5 that the turbine loss at both ends of the magnetic body 12 along the width direction is greater than the turbine loss in the middle part. Please refer to Figure 6. In some embodiments, Figure 6 is a schematic diagram of the peak eddy current loss in the width direction of the magnetic body 12 obtained after calculation and analysis. Among them, the legend unit in Figure 6 is joule, which represents the energy consumed instantaneously in the width direction of the magnetic body 12. Figure 6 shows the maximum eddy current loss generated by the magnetic body 12 when the coupling between the stator magnetic field and the permanent magnet magnetic field is the worst. The eddy current loss of the magnetic body 12 at both ends in the width direction is higher, and the eddy current loss in the middle is smaller. According to a detailed analysis of the eddy current loss at both ends of the magnetic body 12 , the depth of the tooth groove 12 a in the width direction of the magnetic body 12 is determined, which can effectively reduce the eddy current loss at both ends of the magnetic body 12 .

[0061] In step S2, the grain boundary diffusion of heavy rare earth is used to improve the performance of the magnetic steel. The grain boundary diffusion of heavy rare earth can include various methods such as sputtering, evaporation, coating, infiltration or electrodeposition.

[0062] In some embodiments, a grain boundary infiltration treatment of heavy rare earths is adopted. The addition of heavy rare earths by conventional smelting methods will sacrifice some residual magnetic properties and increase raw material costs. The addition of heavy rare earths by conventional smelting methods will cause a large amount of heavy rare earth elements to enter the interior of the grains, resulting in a large consumption of heavy rare earth resources, thereby increasing raw material costs. In addition, the antiferromagnetic coupling between Dy, Tb and Fe atoms will reduce the remanence and maximum magnetic energy product of the magnetic body. The grain boundary diffusion technology uses Tb and Dy as a diffusant. Through diffusion heat treatment, heavy rare earths are introduced from the surface of the magnetic body along the grain boundaries into the interior of the magnetic body, replacing the Nd in the Nd2Fe14B phase. The heavy rare earths are distributed at the grain boundaries and grain surfaces to improve the coercivity of the NdFeB magnetic body, while rarely entering the crystals. This can reduce the adverse effects of heavy rare earths on remanence while improving coercivity. At the same time, the thickness of the thin layer grain boundary phase can be increased, becoming more continuous and smooth, weakening the exchange coupling effect between the grains, and improving the coercivity of the magnetic body. Grain boundary penetration technology can reduce the adverse effects of heavy rare earths while significantly reducing costs.

[0063] In some embodiments, the grain boundary diffusion of heavy rare earth is limited to the comb 122 of the magnetic body 12. By reducing the eddy current loss of the magnetic body, the temperature of the magnetic body is lowered, and the magnetism is stronger. The comb back 121 does not need to be treated with heavy rare earth, thus reducing the use of heavy rare earth and saving costs.

[0064] It should be noted that because the magnetic body 12 is partially cut into comb teeth 122, the exposed surface area of ​​the magnetic body is increased, allowing the grain boundary diffusion process to be applied to a larger surface area of ​​the magnetic body. Furthermore, because the volume of the comb teeth is reduced, the grain boundary diffusion process can be more effectively diffused to the inner center of the comb teeth 122, thereby reducing the difficulty of the grain boundary diffusion process on the magnetic body 12, improving the magnetic body yield, and reducing manufacturing costs.

[0065] In step S3 , a filling portion may be formed in the tooth groove by a dipping process or a brushing process.

[0066] In some specific embodiments, the filling portion 11 between the slots 12a is filled with insulating adhesive, which is treated through an impregnation process. This impregnation process allows the insulating adhesive to better fill each slot 12a of the magnetic body 12. Compared to the manufacturing process of related magnetic steels that requires segmented bonding and then overall processing, this reduces the manufacturing difficulty of the magnetic steel 10, reduces the number of processing steps, and reduces the chance of magnetic steel bumps during the manufacturing process, thereby reducing the magnetic steel scrap rate and improving the manufacturing efficiency of the magnetic steel.

[0067] Another aspect of the embodiments of the present application provides a motor, comprising an iron core 20 and the magnet 10 of any embodiment of the present application. The installation method of the magnet 10 on the iron core 20 can be embedded installation, surface mounting installation, or other forms of installation, which are not limited here. Among them, when embedded, the shape of the magnet can be determined according to the shape of the magnet slot, so that the magnet matches the magnet slot. The shape of the magnet can be a rectangular magnet or a tile-shaped magnet; the cross-section of the magnet can be rectangular or trapezoidal. When surface-mounted, in order to match the inner and outer circular surfaces of the iron core, the shape of the magnet is usually designed to be tile-shaped, that is, the upper and lower surfaces of the magnet are in the form of arc surfaces.

[0068] Referring to Figure 4 , in some embodiments, the magnet 10 is mounted on the motor core 20 in an embedded manner. By reducing the eddy current loss of the magnet 10 , the magnetic flux utilization rate of the magnet 10 in the motor is improved, thereby improving the performance, reliability, and life of the motor.

[0069] The iron core 20 can be a rotor iron core or a stator iron core, which is not limited here.

[0070] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0071] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A magnetic steel body, comprising: Comb the back; as well as A plurality of comb teeth are arranged at intervals along the length direction, and a row of the comb teeth is arranged at both ends of the comb back along the width direction, and tooth grooves are formed between adjacent comb teeth; Wherein, the comb teeth and the comb back are formed in one piece.

2. According to the magnetic steel body of claim 1, the depth of the tooth groove is greater than one tenth of the width of the magnetic steel body and less than nine tenths of the width of the magnetic steel body. 3 . The magnetic steel body according to claim 1 , wherein the direction of the tooth groove is parallel to the width direction or forms an angle with the width direction.

4. A magnetic steel, comprising: The magnetic steel body according to any one of claims 1 to 3; as well as The filling part is filled in the tooth groove to enhance the insulation performance between adjacent comb teeth.

5. The magnetic steel according to claim 4, wherein the comb teeth are infiltrated with heavy rare earth; and / or the filling portion is insulating glue.

6. A method for manufacturing a magnetic steel, comprising: The magnetic steel body is cut and processed to form a structure having a comb back, comb teeth and tooth grooves; Performing a heavy rare earth grain boundary diffusion treatment on the magnetic steel body; A filling portion is formed between the tooth grooves.

7. The manufacturing method according to claim 6, wherein the step of subjecting the magnetic steel body to a grain boundary diffusion treatment of heavy rare earth is specifically subjecting the magnetic steel body to a grain boundary penetration treatment of heavy rare earth; and / or The step of performing a grain boundary diffusion treatment of heavy rare earth on the magnetic steel body specifically comprises: The grain boundary diffusion of heavy rare earth is performed only on the comb teeth, so that the magnetic steel body partially has heavy rare earth.

8. The manufacturing method according to claim 6, wherein the step of forming a filling portion between the tooth grooves comprises: The magnetic steel body is subjected to an impregnation process to form the filling portion between the tooth grooves.

9. The manufacturing method according to claim 6, further comprising: The distribution of eddy current loss in the width direction of the magnetic steel body is analyzed to provide a calculation basis for the processing depth of the tooth groove.

10. A motor, comprising: Iron core; as well as The magnetic steel as described in claim 4 or 5 is arranged on the iron core.

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