A magnetic field device and process for preparing radially radiating rare earth permanent magnet tiles

Abstract

The present invention discloses a magnetic field device for preparing radial radiation rare earth permanent magnet tiles. The magnetic field device comprises an N-pole pulse orientation coil and an S-pole pulse orientation coil. The pole head of the N-pole pulse orientation coil is convex arc-shaped and is equipped with a concave arc-shaped stainless steel non-magnetic compensation plate for leveling. The pole head of the S-pole pulse orientation coil is concave arc-shaped and is equipped with a convex arc-shaped stainless steel non-magnetic compensation plate for leveling, which is convenient for matching with a block magnet mold. Due to the special convex and concave arc pole head setting, a strong radiation orientation magnetic field is generated, ensuring that the prepared block magnet, the radial radiation orientation magnetic tile prepared after cutting processing, has a radiation orientation magnetic field direction in the use of the motor, the magnetic line repulsion phenomenon in the center of the magnetic tile is lighter than that of the ordinary parallel-oriented radial magnetic tile, and the surface magnetism of the center of the magnetic tile is higher than that of the ordinary parallel-oriented radial magnetic tile, so that the magnetic field generated by the magnet of the same volume is greatly improved, so that the motor operation efficiency is improved.

Description

Technical Field

[0001] The invention relates to a magnetic field generating device and process, and in particular to a magnetic field generating device and process for preparing radially radiating rare earth permanent magnet tiles. Background Art

[0002] The existing rare earth permanent magnet sintered NdFeB tile magnets for DC motors are all formed into square or tile-shaped block magnets first, and then cut and ground into radial tile magnets. When the square or tile-shaped block magnets are formed, they are all oriented in parallel magnetic field. Due to the parallel magnetic lines of force, if the inner arc magnetic field is used, the inner arc magnetic lines of force are more likely to repel each other due to the shape of the inner arc, resulting in very low surface magnetism at the center of the inner arc. If the outer arc magnetic field is used, the magnetic lines of force are basically parallel, which cannot meet the requirements of the motor magnetic field. When the motor is used, a radial magnetic field is required, so part of the magnetic energy of the parallel-oriented magnetic tile is wasted. Using a radial ring magnet is the best solution, but the radial ring magnet is affected by the preparation process, and the outer diameter and wall thickness of the prepared circular ring are very limited, that is, the outer diameter is too large and the radial orientation is incomplete when the wall thickness exceeds a certain thickness, so it can only be used for smaller DC motors. A magnetic field device similar to the radiation ring magnet is used to press a single radial radiation magnetic tile. Due to factors such as poor powder fluidity and uneven powder distribution, many problems such as deformation and cracking have not yet been solved. The existing magnetic field device of block rare earth permanent magnets consists of a coil made of a square hollow copper tube, an insulating layer of pure iron core and a pure iron pole head. The end faces of the pure iron pole head are all flat and can only be oriented in parallel. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention is designed to provide a magnetic field device and process for preparing radially radiating rare earth permanent magnet tiles.

[0004] The present invention is achieved through the following technical solutions:

[0005] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the magnetic field device includes an N-pole pulse oriented coil and an S-pole pulse oriented coil, and the N-pole pulse oriented coil and the S-pole pulse oriented coil are both composed of a coil made of a square hollow copper tube, an insulating layer, a pure iron core and a pure iron pole head, and the coil made of the square hollow copper tube can be cooled by pure water in the middle.

[0006] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the pole head ends of the N-pole pulse oriented coil and the S-pole pulse oriented coil assembled with the mold both include pure iron pole heads and stainless steel non-magnetic compensation plates.

[0007] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the end of the pure iron pole head on the S-pole pulse-oriented coil is in a concave arc shape; the end of the pure iron pole head on the N-pole pulse-oriented coil is in a convex arc shape, and the curvature of the concave arc is the same as that of the convex arc.

[0008] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the stainless steel non-magnetic compensation plate arranged in cooperation with the pure iron pole head on the S-pole pulse orientation coil is a convex arc compensation plate, and the stainless steel non-magnetic compensation plate arranged in cooperation with the pure iron pole head on the N-pole pulse orientation coil is a concave arc compensation plate.

[0009] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the pure iron pole head and the pure iron core are connected by stainless steel bolts, and the stainless steel non-magnetic compensation plate is bonded to the pure iron pole head.

[0010] The magnetic field device for preparing radially radiating rare earth permanent magnet tiles is characterized in that the sides of the convex arc compensation plate and the concave arc compensation plate away from the pure iron pole head are both set to be flat, which is convenient for matching with the mold.

[0011] The process for preparing radially radiating rare earth magnetic tiles using the magnetic field device described in claim 1 is characterized by comprising the following steps:

[0012] 1) Add powder to a mold, and use the magnetic field generating device described in claim 1 to perform orientation molding in a magnetic field of not less than 2.5T. The magnetic field strength is specifically that the tile-shaped mold is marked with the magnetic field orientation limit by the direction of the tile-shaped outer arc when the mold is installed; the square mold is marked with the N and S poles of the magnetic field direction during orientation on the pressure head to obtain a radially oriented square or tile-shaped block magnet green body, and after demagnetization, the green body is taken out for vacuum packaging;

[0013] 2) cold isostatic pressing the square or tile-shaped magnet green body obtained in step 1), and then removing the vacuum packaging and placing it into a sintering box;

[0014] 3) Sintering, aging and tempering the block or tile-shaped magnet green body obtained in step 2) to obtain a NdFeB magnet, wherein the sintering temperature is 970-1120° C., the aging temperature is 850-950° C., and the tempering temperature is 450-600° C.;

[0015] 4) Grinding and cutting the NdFeB magnets obtained in step 3) to produce radially oriented magnetic tiles.

[0016] The process for preparing radially radiating rare earth magnetic tiles is characterized in that when preparing magnetic tiles using an outer arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is consistent with that of the block blank to obtain a larger outer arc magnetic field; when preparing magnetic tiles using an inner arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is opposite to that of the block blank to obtain a larger inner arc magnetic field.

[0017] The present invention has a reasonable structural setting, is easy to implement, and has a simple and feasible preparation process. Through the setting of the magnetic field device, it is ensured that the magnetic field direction of the radial magnetic tile magnets that are close to the radiation orientation is consistent with the use direction during the use of the motor. The magnetic line repulsion phenomenon in the center of the magnetic tile is lighter than that of the ordinary parallel-oriented radial magnetic tile. The central surface magnetism of the outer arc of the magnetic tile is higher than that of the ordinary parallel-oriented radial magnetic tile by more than 10%, and the central surface magnetism of the inner arc of the magnetic tile is higher than that of the ordinary parallel-oriented radial magnetic tile by more than 25%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the magnetic field device of the present invention;

[0019] Figure 2 This is a schematic diagram of the direction of magnetic field lines of radiation-oriented magnetic tiles;

[0020] In the figure, 1-N-pole pulse oriented wire package, 2-S-pole pulse oriented wire package, 3-coil, 4-insulating layer, 5-pure iron core, 6-pure iron pole head, 7-mold, 8-stainless steel non-magnetic compensation plate, 81-convex arc compensation plate, 82-concave arc compensation plate. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to the accompanying drawings, and specific implementation methods are given.

[0022] like Figure 1 As shown, the present invention is a magnetic field generating device for preparing block-shaped radiation-oriented rare earth permanent magnets, including an N-pole pulse oriented coil and an S-pole pulse oriented coil, the oriented coils are composed of a coil made of a square hollow copper tube, an insulating layer, a pure iron core and a pure iron pole head, the coil made of the square hollow copper tube can be cooled by pure water in the middle, the pole head ends of the N-pole pulse oriented coil and the S-pole pulse oriented coil assembled with the mold both include a pure iron pole head and a stainless steel non-magnetic compensation plate, the pure iron pole head is connected to the pure iron core by stainless steel bolts, and the stainless steel non-magnetic compensation plate is bonded to the pure iron pole head.

[0023] Among them, the end of the pure iron pole head on the S-pole pulse orientation coil is in a concave arc shape; the end of the pure iron pole head on the N-pole pulse orientation coil is in a convex arc shape, and the curvature of the concave arc is the same as the curvature of the convex arc. The stainless steel non-magnetic compensation plate set in conjunction with the pure iron pole head on the S-pole pulse orientation coil is a convex arc compensation plate, and the stainless steel non-magnetic compensation plate set in conjunction with the pure iron pole head on the N-pole pulse orientation coil is a concave arc compensation plate. The convex arc compensation plate and the concave arc compensation plate are both set to a flat surface on the side away from the pure iron pole head, which is convenient for cooperation with the block magnet mold.

[0024] The process of preparing radially radiating rare earth magnetic tiles by using a magnetic field device comprises the following steps:

[0025] 1) Add powder to a mold, and use the magnetic field generating device described in claim 1 to perform orientation molding in a magnetic field of not less than 2.5T. Specifically, the tile-shaped mold is marked with the magnetic field orientation limit by the direction of the tile-shaped outer arc when the mold is installed; the square mold is provided with N and S pole marks of the magnetic field direction during orientation on the pressure head to obtain a radiation-oriented square or tile-shaped block magnet green body, and after demagnetization, the green body is taken out for vacuum packaging; 2) The square obtained in step 1) is placed in the mold. or tile-shaped block magnet green body is subjected to cold isostatic pressing, and after being stripped of the vacuum packaging, it is loaded into a sintering box; 3) the block or tile-shaped block magnet green body obtained in step 2) is sintered, aged and tempered to obtain a NdFeB magnet, wherein the sintering temperature is 970-1120°C, the aging temperature is 850-950°C, and the tempering temperature is 450-600°C; 4) the NdFeB magnet obtained in step 3) is ground and cut to make a radially oriented magnetic tile.

[0026] Among them, when preparing magnetic tiles using an external arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is consistent with that of the block blank to obtain a larger external arc magnetic field; when preparing magnetic tiles using an internal arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is opposite to that of the block blank to obtain a larger internal arc magnetic field.

[0027] A magnetic field device prepared by the above device and process, such as Figure 2 As shown, the block-shaped radially oriented blanks and radially oriented magnetic tiles are similar to radially oriented due to their deflected orientation, the repulsion of the inner arc magnetic lines of force is reduced, and the surface magnetism at the center point of the inner arc is greatly improved.

[0028] Example 1

[0029] 1) Add 38SH performance powder into a block mold, use the magnetic field generating device described in claim 1 to carry out orientation molding under a magnetic field of not less than 2.5T, the pressure head is provided with N and S pole marks of the magnetic field direction during orientation, and a radially oriented block magnet green body is obtained. After demagnetization, the green body is taken out and vacuum packaged; 2) The block magnet green body obtained in step 1) is subjected to cold isostatic pressing, and after the vacuum package is peeled off, it is loaded into a sintering box; 3) The block magnet green body obtained in step 2) is sintered, aged and tempered to obtain a NdFeB magnet, wherein the sintering temperature is 1070°C, the aging temperature is 900°C, and the tempering temperature is 500°C; 4) The block magnet obtained in step 3) is ground and cut so that the outer arc of the magnetic tile is consistent with the orientation direction of the block blank to produce a radially oriented magnetic tile.

[0030] Example 2

[0031] 1) Powder with 38SH performance is added to a tile-shaped mold, the outer arc direction of the tile-shaped mold is toward the N pole, and the magnetic field generating device described in claim 1 is used to perform orientation molding under a magnetic field of not less than 2.5T to obtain a radially oriented block tile-shaped magnet green body, and the green body is taken out after demagnetization and vacuum packaged; 2) The block tile-shaped magnet green body obtained in step 1) is subjected to cold isostatic pressing, and after the vacuum package is peeled off, it is loaded into a sintering box; 3) The block tile-shaped magnet green body obtained in step 2) is sintered, aged and tempered to obtain a NdFeB magnet, wherein the sintering temperature is 1070°C, the aging temperature is 900°C, and the tempering temperature is 500°C; 4) The block tile-shaped magnet obtained in step 3) is ground and cut with the outer arc opposite to the orientation direction of the square blank to produce a radially oriented magnetic tile.

[0032] Comparative Example 1

[0033] 1) Adding 38SH performance powder into a mold, using a common parallel orientation magnetic field generating device, magnetic field orientation molding is carried out under a magnetic field of not less than 2.5T to obtain a block or tile-shaped block magnet green body, and after demagnetization, the green body is taken out and vacuum packaged; 2) The block or tile-shaped block magnet green body obtained in step 1) is subjected to cold isostatic pressing, and after the vacuum package is peeled off, it is loaded into a sintering box; 3) The block or tile-shaped block magnet green body obtained in step 2) is subjected to sintering, aging and tempering treatment to obtain a NdFeB magnet, wherein the sintering temperature is 1070°C, the aging temperature is 900°C, and the tempering temperature is 500°C; 4) The block or tile-shaped block magnet obtained in step 3) is ground and cut to produce a radially oriented magnetic tile.

[0034] Example 1 and Comparative Example 1 using an outer arc magnetic field were both processed into R36*r36*41*41.3°*3 magnetic tiles, which were then magnetized and the surface magnetism of the inner arc center point was measured. The results are shown in Table 1.

[0035] Table 1

[0036] Outer arc center surface magnetic field (Gs) Surface magnetic field of outer arc corner (Gs) Surface magnetic difference (Gs) Example 1 2000 2300 300 Comparative Example 1 1760 2310 550

[0037] The Example 2 and the Comparative Example 1 using the inner arc magnetic field magnetic tiles were processed into R36*r36*41*41.3°*3 magnetic tiles, and then magnetized. The surface magnetism at the center point of the inner arc was measured. The results are shown in Table 2.

[0038] Table 2

[0039] Inner arc center surface magnetism (Gs) Inner arc corner surface magnetism (Gs) Surface magnetic difference (Gs) Example 2 1500 3000 1500 Comparative Example 1 440 3390 2950

[0040] From the above comparison, it can be seen that the radially radiating rare earth permanent magnet tiles prepared by the magnetic field generating device with the special shape of the pole head of the present invention, the radially radiating square or block-shaped tile-shaped magnets prepared by processing, the embodiment 1 using the outer arc magnetic field has an outer arc center surface magnetism 12% higher than that of the magnetic tile of the comparative example 1, and the embodiment 2 using the inner arc magnetic field has an inner arc center surface magnetism 3 times higher than that of the magnetic tile of the comparative example 1. From the above comparison, it can be seen that whether the magnetic field uses the outer arc or the inner arc, the center surface magnetism is greatly improved compared with the comparative example, and the difference in surface magnetism between the center and the corner is significantly reduced, making the magnetic field at the center and corner of the magnet more uniform, and making the magnetic field distribution waveform more conducive to improving the working efficiency of the motor.

Claims

1. A magnetic field device for preparing radially radiating rare earth permanent magnet tiles, characterized in that The magnetic field device comprises an N-pole pulse oriented coil (1) and an S-pole pulse oriented coil (2), wherein the N-pole pulse oriented coil (1) and the S-pole pulse oriented coil (2) are both composed of a coil (3) made of a square hollow copper tube, an insulating layer (4), a pure iron core (5) and a pure iron pole head (6); the pole head ends of the N-pole pulse oriented coil (1) and the S-pole pulse oriented coil (2) assembled with a mold (7) both comprise a pure iron pole head (6) and a stainless steel non-magnetic compensation plate (8); the end of the pure iron pole head (6) on the S-pole pulse oriented coil (2) is in a concave arc shape; the pure iron pole head (6) on the N-pole pulse oriented coil (1) is The end is in a convex arc shape, and the curvature of the concave arc shape is the same as that of the convex arc shape; the stainless steel non-magnetic compensation plate arranged in cooperation with the pure iron pole head on the S-pole pulse orientation line package is a convex arc compensation plate (81), and the stainless steel non-magnetic compensation plate arranged in cooperation with the pure iron pole head on the N-pole pulse orientation line package is a concave arc compensation plate (82); the convex arc compensation plate (81) and the concave arc compensation plate (82) are arranged in a flat shape on the side away from the pure iron pole head (6) to facilitate cooperation with the mold (7); the pure iron pole head (6) and the pure iron core (5) are connected by stainless steel bolts, and the stainless steel non-magnetic compensation plate (8) and the pure iron pole head (6) are bonded.

2. A process for preparing radially radiating rare earth magnetic tiles using the magnetic field device according to claim 1, characterized in that The following steps are involved: 1) Add powder to a mold, and use the magnetic field device described in claim 1 to perform orientation molding in a magnetic field of not less than 2.5T. Specifically, the tile-shaped mold is marked with the magnetic field orientation limit by the direction of the tile-shaped outer arc when the mold is installed; the square mold is provided with N and S pole marks of the magnetic field direction during orientation on the pressure head to obtain a radiation-oriented square or tile-shaped block magnet green body, and after demagnetization, the green body is taken out for vacuum packaging; 2) cold isostatic pressing the square or tile-shaped magnet green body obtained in step 1), and then removing the vacuum packaging and placing it into a sintering box; 3) Sintering, aging and tempering the square or tile-shaped block magnet green body obtained in step 2) to obtain a NdFeB magnet, wherein the sintering temperature is 970-1120° C., the aging temperature is 850-950° C., and the tempering temperature is 450-600° C.; 4) Grinding and cutting the NdFeB magnets obtained in step 3) to produce radially oriented magnetic tiles.

3. The process as claimed in claim 2, characterized in that When preparing magnetic tiles using an external arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is consistent with that of the block blank to obtain a larger external arc magnetic field; when preparing magnetic tiles using an internal arc magnetic field, the block blank is radiantly oriented, and the orientation direction of the outer arc of the magnetic tile is opposite to that of the block blank to obtain a larger internal arc magnetic field.

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