Fixing device and fixing method for permanent magnet magnetic aging

Abstract

The present invention relates to a fixing device and a fixing method for the stable magnetic aging of permanent magnets. The fixing device is used to fix a permanent magnet in a magnetized state for stable magnetic aging, and the fixing device includes: a mounting frame, including a storage cavity and an observation groove extending from the outer peripheral wall of the mounting frame to the storage cavity. A cover body is detachably connected to the mounting frame and closes the opening of the storage cavity. An adjusting member is connected to the cover body and extends toward the storage cavity. The storage cavity is used to store permanent magnets, and the adjusting member is used to push the permanent magnets in the storage cavity to adjust the distance between adjacent permanent magnets. The permanent magnets are assembled to the mounting frame one by one, and the air gap field strength can be adjusted by the extended length of the adjusting member by utilizing the mutual balance between the repulsive force generated when the permanent magnets are placed against each other and the thrust of the adjusting member.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic materials, and in particular to a fixing device and a fixing method for magnetic stabilization and aging of permanent magnets. Background Art

[0002] The traditional fixed magnetic stabilization method is to fix the permanent magnet with a certain fixing device and then place it in a heat treatment furnace, keep it warm for a certain period of time, and cool it to room temperature to obtain a stable magnetic sample. However, the traditional fixed magnetic stabilization method mainly includes: (1) open circuit fixed magnetic stabilization method. In this method, the magnet is easily interfered by the surrounding magnetic field when placed at a close distance, and it will take up a relatively large space when placed at a distance; (2) semi-open circuit fixed magnetic stabilization method. In this method, the magnetic circuits of the two poles of the magnet are different, which will lead to a large difference in the magnetic flux density of the N pole and S pole of the magnet after stabilization, and cannot meet the requirements of high uniformity, high consistency, and high symmetry for precision instruments and meters; (3) closed circuit fixed magnetic stabilization method. This method is complicated to disassemble and assemble. The magnet is prone to collision during the adsorption process, causing the permanent magnet to have missing edges and corners. At the same time, this method cannot adjust the air gap field to adapt to the fixed magnetic stabilization requirements of different application environments. Different application environments make the magnetic circuit of permanent magnet materials change during use. Therefore, the magnetic stabilization process should provide a variable air gap field as much as possible to adapt to complex environments. Summary of the Invention

[0003] Based on this, it is necessary to provide a fixing device and a fixing method for stabilizing magnetic aging of permanent magnets to address the above problems.

[0004] The present invention discloses a fixing device for stable magnetic aging of a permanent magnet, which is used to fix a permanent magnet in a magnetized state for stable magnetic aging. The fixing device comprises:

[0005] The mounting frame includes a receiving cavity and an observation slot extending from an outer peripheral wall of the mounting frame to the receiving cavity;

[0006] a cover body, detachably connected to the mounting frame and closing the opening of the storage cavity;

[0007] an adjusting member connected to the cover body and extending into the receiving cavity, and the length of the adjusting member extending into the receiving cavity is adjustable;

[0008] The receiving cavity is used to receive permanent magnets, and the adjusting member is used to push the permanent magnets in the receiving cavity to adjust the distance between adjacent permanent magnets.

[0009] In one embodiment, the receiving cavity has a cylindrical cross-section, and the cross-sectional dimension of the receiving cavity is slightly larger than the cross-sectional dimension of the permanent magnet.

[0010] In one embodiment, the observation slot is linear, and an extending direction of the observation slot is parallel to a center line of the receiving cavity.

[0011] In one embodiment, the mounting frame further includes scale lines arranged on the outer peripheral wall, and the scale lines are distributed along the length direction of the observation slot.

[0012] In one embodiment, the mounting bracket further includes an auxiliary hole extending through the receiving cavity, and the auxiliary hole is away from the opening direction of the receiving cavity.

[0013] In one embodiment, the adjusting member is threadedly connected to the cover body, and a rotation centerline of the adjusting member coincides with or is parallel to a centerline of the receiving cavity.

[0014] In one embodiment, the mounting bracket, the cover, and the adjusting member are all made of a material that is non-magnetic and has high thermal conductivity.

[0015] The present invention discloses a method for fixing a permanent magnet for stable magnetic aging, using the fixing device described above, the fixing method comprising:

[0016] Place the permanent magnets into the mounting frame sequentially from the opening of the receiving cavity, wherein the magnetic poles of the opposite ends of two adjacent permanent magnets are the same and the permanent magnets are in a magnetized state;

[0017] Connecting the cover to the mounting frame and closing the opening of the storage cavity;

[0018] The adjusting member is extended into the receiving cavity along the cover body, and the length of the adjusting member extended into the receiving cavity can be adjusted and pushed against the closest permanent magnet to adjust the distance between two adjacent permanent magnets;

[0019] Placing the fixture in a heat treatment furnace and maintaining the temperature for a preset period of time;

[0020] The fixture was cooled to room temperature in the furnace and then the permanent magnet was taken out.

[0021] In one embodiment, adjusting the distance between two adjacent permanent magnets includes:

[0022] A Hall probe is used to measure the air gap field between two adjacent permanent magnets along the observation slot.

[0023] In one embodiment, the number of the permanent magnets is greater than or equal to 3.

[0024] In the present invention, permanent magnets are individually assembled onto a mounting frame. The air gap field strength can be adjusted by adjusting the extension length of the adjusting member, leveraging the balancing effect between the repulsive force generated when the permanent magnets are placed against each other and the thrust of the adjusting member. The installation and spacing parameters of the permanent magnets can be observed through an observation slot, facilitating the observation and recording of the permanent magnet installation parameters. Furthermore, the storage cavity can limit the range of motion of the permanent magnets, enabling rapid, concentric placement and spacing control of the permanent magnets, thus meeting the requirements for stable magnetic aging of permanent magnet materials under adjustable air gap magnetic field conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the fixing device of the present invention;

[0026] Figure 2 is a schematic cross-sectional structural diagram of the fixing device of the present invention;

[0027] Figure 3 is a schematic cross-sectional structural diagram of the permanent magnet of the present invention when it is removed from the mounting frame;

[0028] Figure 4 It is a structural diagram of a semi-open circuit fixture;

[0029] Figure 5 It is a structural diagram of a top-placed colloid bonding and fixing device.

[0030] In the figure: 10, mounting frame; 11, storage cavity; 12, observation slot; 13, auxiliary hole; 14, scale line; 20, cover; 21, first threaded hole; 22, second threaded hole; 30, adjustment member; 40, permanent magnet; 50, push rod; 60, permanent magnet; 61, electrical pure iron plate; 70, permanent magnet; 71, colloid. DETAILED DESCRIPTION

[0031] The fixing device and fixing method for the stable magnetic aging of a permanent magnet provided by the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1 and Figure 2 As shown, the present invention provides a fixing device for the stable magnetic aging of a permanent magnet 40, which is used to fix the permanent magnet 40 in a magnetized state for stable magnetic aging. The fixing device includes: a mounting frame 10, a cover body 20 and an adjusting member 30. The mounting frame 10 includes a storage cavity 11 and an observation groove 12 that passes through the outer peripheral wall of the mounting frame 10 to the storage cavity 11. The mounting frame 10 is made of a rigid material, and the storage cavity 11 is a groove-shaped or hole-shaped structure formed by the end of the mounting frame 10. The storage cavity 11 is used to store the permanent magnet 40. The observation groove 12 is a long hole structure, which connects the storage cavity 11 with the external space to facilitate the user to penetrate the assembly state of the permanent magnet 40 in the storage cavity 11 and to facilitate the detection of relevant magnetic parameters of the permanent magnet 40. The magnetic poles of the opposite ends of two adjacent permanent magnets 40 are the same, and the permanent magnet 40 is in a magnetized state. That is, two adjacent permanent magnets 40 are placed top to top, with the N pole of the first permanent magnet 40 facing the N pole of the second permanent magnet 40 , the S pole of the second permanent magnet 40 facing the S pole of the third permanent magnet 40 , and so on.

[0033] After the permanent magnet 40 is assembled to the mounting frame 10, the cover 20 is detachably connected to the mounting frame 10 and closes the opening of the storage cavity 11, thereby enclosing the permanent magnet 40 within the mounting frame 10. Optionally, the cover 20 is threadedly connected to the mounting frame 10, wherein one end of the cover 20 is provided with a first threaded hole 21 and a second threaded hole 22, and the axis of the first threaded hole 21 is parallel to or coincides with the axis of the second threaded hole 22. The first threaded hole 21 is detachably connected to the mounting frame 10, so that the cover 20 is enclosed at one end of the mounting frame 10. Optionally, the cover 20 is snap-fastened and screwed to the mounting frame 10, wherein the cover 20 is provided with a barb structure, and the mounting frame 10 is provided with a guide groove and a locking boss provided on one side of the guide groove. The cover 20 slides along the guide groove and abuts against the end of the mounting frame 10, and then rotates so that the barb engages with the locking boss. Optionally, the cover 20 and the mounting frame 10 are locked together by a locking member. For example, the cover 20 is locked to the mounting bracket 10 by fasteners to close the opening of the receiving cavity 11 .

[0034] The adjusting member 30 is connected to the cover 20 and extends into the receiving cavity 11. The adjusting member 30 is used to push against the permanent magnets 40 in the receiving cavity 11 to adjust the spacing between adjacent permanent magnets 40. The adjusting member 30 can telescope relative to the cover 20 to adjust the length of the permanent magnets 40 extending into the receiving cavity 11, thereby pushing the permanent magnets 40 in the receiving cavity 11 to move.

[0035] The permanent magnets 40 are assembled one by one to the mounting frame 10. The air gap field strength can be adjusted by adjusting the extension length of the adjusting member 30, utilizing the mutual balancing effect between the repulsive force generated when the permanent magnets 40 are placed against each other and the thrust of the adjusting member 30. The installation status and spacing parameters of the permanent magnets 40 are observed through the observation slot 12, making it convenient to observe and record the installation parameters of the permanent magnets 40. Furthermore, the storage cavity 11 can limit the range of motion of the permanent magnets 40, enabling rapid concentric placement and spacing control of the permanent magnets 40, meeting the requirements for stable magnetic aging of permanent magnet materials under adjustable air gap magnetic field conditions.

[0036] In one embodiment, the storage cavity 11 has a cylindrical cross-section, and the cross-sectional dimensions of the storage cavity 11 are slightly larger than the cross-sectional dimensions of the permanent magnet 40. The inner cavity wall of the storage cavity 11 is used to limit the range of motion of the permanent magnet 40 to achieve rapid concentric placement of the permanent magnet 40. For example, if the permanent magnet 40 is cylindrical or annular, the cross-section of the storage cavity 11 is circular. Alternatively, if the permanent magnet 40 is prismatic, the cross-sectional dimensions of the storage cavity 11 are circular or prismatic. Among them, when the storage cavity 11 is circular, it fits the circumscribed circle of the outline of the permanent magnet 40. The cross-sectional dimensions of the storage cavity 11 are slightly larger than the cross-sectional dimensions of the permanent magnet 40, which can facilitate the disassembly and assembly of the permanent magnet 40 and achieve rapid concentric placement of the permanent magnet 40, with good magnetic aging effect.

[0037] The observation slot 12 can observe the assembly status and corresponding assembly dimensions of the permanent magnet 40 in the storage cavity 11, which is convenient for users to adjust and measure. Optionally, the observation slot 12 is linear, and the extension direction of the observation slot 12 is parallel to the center line of the storage cavity 11. The observation slot 12 is a long hole structure distributed in a straight line, which can intuitively judge the status of the permanent magnet 40. Furthermore, the mounting bracket 10 also includes scale lines 14 provided on the outer wall, and the scale lines 14 are distributed along the length direction of the observation slot 12. The user reads the scale lines 14 engraved on the mounting bracket 10, and observes the spacing distribution status between multiple adjacent permanent magnets 40 through the observation slot 12, and the reading and judgment are intuitive.

[0038] After the permanent magnet 40 completes the magnetic stabilization aging step, the permanent magnet 40 that has completed the magnetic stabilization aging needs to be taken out from the mounting frame 10. For example, the permanent magnet 40 is poured out after opening the cover body 20, or the permanent magnet removal body outside the mounting frame 10 is used to absorb and extract the permanent magnet 40 in the mounting frame 10. In one embodiment, the mounting frame 10 also includes an auxiliary hole 13 that passes through the storage cavity 11, and the auxiliary hole 13 deviates from the opening direction of the storage cavity 11. The aperture size of the auxiliary hole 13 is smaller than the aperture of the storage cavity 11 to form a structure similar to a stepped hole. The aperture size of the auxiliary hole 13 is smaller than the outer diameter of the permanent magnet 40, and the cylindrical push rod 50 can be inserted into the storage cavity 11 along the auxiliary hole 13 to push the permanent magnet 40 out of the opening of the storage cavity 11, making it convenient to take out.

[0039] The adjusting member 30 is connected to the cover body 20 and can be linearly extended and retracted relative to the cover body 20 to push the permanent magnet 40 to move. For example, the adjusting member 30 is configured as a rod-shaped structural member such as a pin, which is inserted into the cover body 20 and pushes the permanent magnet 40 to be connected; or, the adjusting member 30 is configured as a threaded structural member such as a bolt or a screw, which is screwed to the cover body 20 and pushes the permanent magnet 40 to be connected. In one embodiment, the adjusting member 30 is threadedly connected to the cover body 20, and the rotation centerline of the adjusting member 30 coincides with or is parallel to the centerline of the storage cavity 11. The adjusting member 30 is screwed to the cover body 20 to lock the position of the permanent magnet 40 through the force of the thread, and can also facilitate telescopic movement along the cover body 20. Optionally, the adjusting member 30 is configured as a fastener such as a screw or a bolt. Specifically, the adjusting member 30 is connected to the second threaded hole 22 and extends and retracts along the second threaded hole 22.

[0040] The fixing device is used to stabilize the magnetic aging of the permanent magnet 40 to improve the stability of the magnetic parameters of the permanent magnet 40. In one embodiment, the mounting frame 10, cover 20, and adjustment member 30 are all made of non-magnetic materials with high thermal conductivity. For example, the mounting frame 10, cover 20, and adjustment member 30 are made of non-magnetic metals such as copper.

[0041] like Figure 1 and Figure 3As shown, the fixing device disclosed in the above embodiment is applied to the stable magnetic aging of the permanent magnet 40, wherein the fixing method of the stable magnetic aging of the permanent magnet 40 includes the following steps:

[0042] S101, place the permanent magnets 40 into the mounting frame 10 in sequence from the opening of the storage cavity 11, wherein the magnetic poles of the opposite ends of two adjacent permanent magnets 40 are the same, and the permanent magnets 40 are in a magnetized state. The size of the permanent magnet 40 matches the size of the storage cavity 11, and the permanent magnet 40 is located at the center of the storage cavity 11. The magnetic poles of the opposite ends of two adjacent permanent magnets 40 are the same, and the permanent magnet 40 is in a magnetized state. That is, the two adjacent permanent magnets 40 are placed top to top, with the N pole of the first permanent magnet 40 facing the N pole of the second permanent magnet 40, the S pole of the second permanent magnet 40 facing the S pole of the third permanent magnet 40, and so on. Optionally, the number of the permanent magnets 40 is greater than or equal to 3.

[0043] S102 , connecting the cover 20 to the mounting frame 10 and closing the opening of the storage cavity 11 .

[0044] S103: Extend the adjusting member 30 along the cover 20 into the receiving cavity 11. The length of the adjusting member 30 extending into the receiving cavity 11 is adjustable and pushes against the closest permanent magnet 40 to adjust the spacing between two adjacent permanent magnets 40. The length of the adjusting member 30 is sufficient to ensure that the screw portion can closely contact and abut the closest permanent magnet 40 after passing through the cover 20, and then adjust the spacing through the repulsive force between the permanent magnets 40. Specifically, slowly rotate the adjusting member 30 and check the spacing between the permanent magnets 40 through the graduated observation slot 12 to meet the stable magnetic aging spacing requirements of the permanent magnets 40.

[0045] S104, placing the fixing device in a heat treatment furnace for a preset insulation time. During the insulation, the specific insulation temperature is selected according to the characteristics of the permanent magnet 40. In one embodiment, the insulation temperature can be preferably 100°C to 400°C.

[0046] S105: After the fixture cools to room temperature in the furnace, the permanent magnets 40 are removed. In this step, the adjustment member 30 is rotated in the opposite direction until it is completely removed from the cover 20, completely separating the cover 20 from the storage cavity 11. A rod-shaped or cylindrical push rod 50 is inserted into the auxiliary hole 13 to assist in sequentially removing the permanent magnets 40 from the storage cavity 11. The permanent magnets 40 samples removed from the storage cavity 11 at both ends are then removed, resulting in the stabilized permanent magnets 40.

[0047] Furthermore, the adjusting the distance between the two adjacent permanent magnets 40 further includes: using a Hall probe to measure the air gap field between the two adjacent permanent magnets 40 along the observation slot 12 .

[0048] Hereinafter, the fixing device and fixing method for the magnetic stabilization and aging of the permanent magnet will be further described through the following specific embodiments.

[0049] Example 1:

[0050] The mounting frame 10, the cover 20 and the adjusting member 30 are all made of pure copper. The method for fixing the permanent magnet 40 to stabilize magnetic aging includes the following steps:

[0051] (1) Seven AlNiCo magnets with a size of 3 mm * 5 mm * 6 mm were selected and magnetized using a 2 T pulse magnetic field. The N pole and S pole were marked on the upper and lower end surfaces of the magnets respectively.

[0052] (2) Use the auxiliary holes 13 at the bottom of the mounting frame 10 to assist the AlNiCo magnets to enter the mounting frame 10 in sequence, ensuring that the magnets are placed top to top (N pole to N pole, S pole to S pole);

[0053] (3) Use the perforated cover 20 to block the AlNiCo magnet in the mounting frame 10;

[0054] (4) Insert the adjusting member 30 through the screw hole of the cover 20, slowly rotate the adjusting member 30, and check the spacing between the AlNiCo magnets through the graduated observation slot 12;

[0055] (5) Adjust the spacing between the AlNiCo magnets to 0.1 mm, place the Hall probe in the middle of the top magnet at the observation slot 12, and test the maximum air gap field strength of 70 mT by contacting the probe with the surface of the observation slot 12. Place the permanent magnet material fixture at 300°C for 24 hours and then cool it to room temperature.

[0056] (6) Slowly rotate the adjusting member 30 in the reverse direction to completely withdraw the cover 20, and completely separate the cover 20 from the mounting bracket 10;

[0057] (7) Using the auxiliary hole 13 at the bottom of the mounting frame 10, the AlNiCo magnets are removed from the mounting frame 10 in sequence, and the samples at both ends are removed to obtain 5 AlNiCo magnets with magnetic stabilization treatment.

[0058] Example 2:

[0059] The mounting frame 10, the cover 20 and the adjusting member 30 are all made of pure copper. The method for fixing the permanent magnet 40 to stabilize magnetic aging includes the following steps:

[0060] (1) Select 12 samarium cobalt magnets with a size of Φ9mm*6mm, magnetize them with an 8T pulse magnetic field, and mark the north and south poles on the upper and lower end surfaces of the magnets respectively;

[0061] (2) Use the auxiliary holes 13 at the bottom of the mounting frame 10 to assist the samarium cobalt magnets to enter the mounting frame 10 in sequence, ensuring that the magnets are placed top to top (N pole to N pole, S pole to S pole);

[0062] (3) Using a perforated cover 20 to block the samarium cobalt magnet in the mounting frame 10;

[0063] (4) Insert the adjusting member 30 through the screw hole of the cover 20, slowly rotate the adjusting member 30, and check the spacing between the samarium cobalt magnets through the graduated observation slot 12;

[0064] (5) Adjust the spacing between the samarium cobalt magnets to 8 mm, place the Hall probe in the middle of the top magnet at observation slot 12, and test the maximum air gap field strength of 90 mT with the probe touching the surface of observation slot 12. Place the permanent magnet material fixture at 200°C for 36 hours and then cool it to room temperature.

[0065] (6) Slowly rotate the adjusting member 30 in the reverse direction to completely withdraw the cover 20, and completely separate the cover 20 from the mounting bracket 10;

[0066] (7) Using the auxiliary hole 13 at the bottom of the mounting frame 10, the samarium cobalt magnets are taken out of the mounting frame 10 in sequence, and the samples at both ends are removed to obtain 10 samarium cobalt magnets with magnetic stabilization treatment.

[0067] Example 3:

[0068] The mounting frame 10, the cover 20 and the adjusting member 30 are all made of pure copper. The method for fixing the permanent magnet 40 to stabilize magnetic aging includes the following steps:

[0069] (1) Select 12 NdFeB magnets with a size of Φ9mm*5mm, magnetize them with an 8T pulse magnetic field, and mark the N pole and S pole on the upper and lower end surfaces of the magnets respectively;

[0070] (2) Use the auxiliary holes 13 at the bottom of the mounting frame 10 to assist the NdFeB magnets to enter the mounting frame 10 in sequence, ensuring that the magnets are placed top to top (N pole to N pole, S pole to S pole);

[0071] (3) Use the perforated cover 20 to block the NdFeB magnet in the mounting frame 10;

[0072] (4) Insert the adjusting member 30 through the screw hole of the cover 20, slowly rotate the adjusting member 30, and check the spacing between the NdFeB magnets through the graduated observation slot 12;

[0073] (5) Adjust the spacing between the NdFeB magnets to 15 mm. Place the Hall probe in the middle of the top magnet at observation slot 12, with the probe touching the surface of observation slot 12. Test the maximum air gap field strength to be 105 mT. Place the permanent magnet material fixture at 100°C for 48 hours and then cool it to room temperature.

[0074] (6) Slowly rotate the adjusting member 30 in the reverse direction to completely withdraw the cover 20, and completely separate the cover 20 from the mounting bracket 10;

[0075] (7) Using the auxiliary hole 13 at the bottom of the mounting frame 10 to assist the NdFeB magnets to be taken out of the mounting frame 10 in turn, and removing the samples at both ends, 10 NdFeB magnets with magnetic stabilization treatment are obtained.

[0076] Example 4:

[0077] The mounting frame 10, the cover 20 and the adjusting member 30 are all made of pure copper. The method for fixing the permanent magnet 40 to stabilize magnetic aging includes the following steps:

[0078] (1) Select 12 samarium cobalt magnets with a size of Φ9mm*4mm, and ensure that the room temperature remanence, coercive force, and magnetic energy product deviations among the 12 samarium cobalt magnets are all within 5%, and the surface magnetic deviations of the center positions of the N pole and S pole of the same magnet in the magnetized state are within 5%, and the surface magnetic deviations of the center positions of the N pole and S pole of different magnets are also within 5%. 10 of the samarium cobalt magnets are numbered 1#-10#, and the 12 magnets are magnetized with an 8T pulse magnetic field. The N pole and S pole are marked on the upper and lower end surfaces of the 12 magnets respectively, and the surface magnetic properties of the center positions of the 10 numbered samarium cobalt magnets are tested in turn. The results are shown in Table 1.

[0079] (2) Using the auxiliary holes 13 at the bottom of the mounting frame 10, the 12 samarium-cobalt magnets are sequentially placed into the mounting frame 10. The 10 numbered magnets are placed in order in the mounting frame 10, and the two unnumbered magnets are randomly placed at the bottom and top of the storage cavity 11, ensuring that the 12 magnets are placed top to top (N pole to N pole, S pole to S pole);

[0080] (3) Using a perforated cover 20 to block the samarium cobalt magnet in the mounting frame 10;

[0081] (4) Insert the adjusting member 30 through the screw hole of the cover 20, slowly rotate the adjusting member 30, and check the spacing between the samarium cobalt magnets through the graduated observation slot 12;

[0082] (5) Adjust the spacing between the samarium cobalt magnets to 0.1 mm, place the Hall probe in the middle of the top magnet at observation slot 12, and test the maximum air gap field strength of 230 mT with the probe touching the surface of observation slot 12. Place the permanent magnet material fixture at 100°C for 48 hours and then cool it to room temperature.

[0083] (6) Slowly rotate the adjusting member 30 in the reverse direction to completely withdraw the cover 20, and completely separate the cover 20 from the mounting bracket 10;

[0084] (7) The auxiliary holes 13 at the bottom of the mounting frame 10 were used to assist the samarium cobalt magnets to be taken out of the mounting frame 10 in turn. The samples at both ends were removed to obtain 10 samarium cobalt magnets that had been stabilized. The surface magnetism of the center position of the samarium cobalt magnets was tested in turn. The results are shown in Table 1.

[0085] Table 1

[0086]

[0087] From the data in Table 1, it can be seen that after magnetic stabilization and aging, the surface magnetic loss of the N pole of the samarium cobalt magnet ranges from 0.42% to 1.67%, and the surface magnetic loss of the S pole ranges from 0 to 1.67%. The absolute value of the difference between the N pole and the S pole before and after magnetic stabilization decreases from 1mT to 7mT to 1mT to 4mT, and the average difference decreases from 3.7mT to 2.8mT. The surface magnetic symmetry and consistency of the N pole and S pole increase.

[0088] Comparative Example 1

[0089] The semi-open circuit fixing method for magnetic stabilization aging of the permanent magnet 60 comprises the following steps:

[0090] (1) Select 10 SmCo magnets with a size of Φ9mm*4mm, and ensure that the room temperature remanence, coercive force, and magnetic energy product deviations among the 10 SmCo magnets are all within 5%, and the surface magnetic deviations of the center positions of the N poles and S poles of the same magnet in the magnetized state are within 5%, and the surface magnetic deviations of the center positions of the N poles and S poles of different magnets are also within 5%. The 10 SmCo magnets are numbered 1#-10# and magnetized with an 8T pulse magnetic field. The N poles and S poles are marked on the upper and lower end surfaces of the 10 magnets respectively, and the surface magnetic properties of the center positions of the SmCo magnets are tested in turn. The results are shown in Table 2.

[0091] (2) Samarium cobalt magnets are sequentially adsorbed on the electrical pure iron plate 61 at intervals, as shown in FIG. Figure 4 As shown, the samarium cobalt magnets adsorb one side of the electrical pure iron plate 61 with the same magnetic pole (both N pole or S pole), and the side spacing between the samarium cobalt magnets is 50 mm;

[0092] (3) The samarium cobalt magnet adsorbing the electrical pure iron plate 61 is placed at 100°C for 48 hours and then cooled to room temperature.

[0093] (4) Remove the samarium cobalt magnets one by one to test the center position of the surface magnetism. The results are shown in Table 2.

[0094] Table 2

[0095]

[0096]

[0097] As shown in Table 2, after stable magnetic aging, the N-pole surface magnetic loss of the samarium-cobalt magnet ranges from 0 to 0.85%, and the S-pole surface magnetic loss ranges from 0 to 1.25%. The absolute value of the difference between the N-pole and S-pole values ​​before and after stable magnetic aging changes from 3mT to 9mT to 2mT to 9mT, and the average difference decreases from 5.5mT to 5.4mT. Comparative Example 4 shows that before and after the semi-open circuit fixed stable magnetic aging, the degree of surface magnetic attenuation of the N-pole and S-pole values ​​is relatively small, and the absolute value of the difference between the N-pole and S-pole values ​​also changes slightly, failing to achieve the effect of improving surface magnetic consistency and symmetry.

[0098] Comparative Example 2

[0099] The method for bonding and fixing the permanent magnet 70 with the colloid 71 while placing the permanent magnet 70 on top of the permanent magnet 70 for stable magnetic aging includes the following steps:

[0100] (1) Select 12 samarium cobalt magnets with a size of Φ9mm*4mm, and ensure that the room temperature remanence, coercive force, and magnetic energy product deviations among the 12 samarium cobalt magnets are all within 5%, and the surface magnetic deviations of the center positions of the N pole and S pole of the same magnet in the magnetized state are within 5%, and the surface magnetic deviations of the center positions of the N pole and S pole of different magnets are also within 5%. Mark 10 of the samarium cobalt magnets as 1#-10#, magnetize the 12 magnets with an 8T pulse magnetic field, mark the N pole and S pole on the upper and lower end surfaces of the 12 magnets, and test the surface magnetic center positions of the 10 numbered samarium cobalt magnets in turn. The results are shown in Table 3.

[0101] (2) Adjust the spacing between the samarium cobalt magnets to 0.1 mm and glue the samarium cobalt magnets with 150°C high-temperature glue 71. The 10 numbered magnets are fixed in sequence, and the two unnumbered magnets are randomly glued to the ends of the numbered magnets. Ensure that the 12 magnets are fixed concentrically and placed top to top (N pole to N pole, S pole to S pole). Figure 5 As shown;

[0102] (3) Place the Hall probe in the middle of the side of the top magnet and test the maximum air gap field strength with the probe touching the side of the magnet, which is 238 mT.

[0103] (4) Place the fixed samarium cobalt magnet at 100°C for 48 hours and cool it to room temperature;

[0104] (5) After taking out the samarium cobalt magnet, hold it with plastic tweezers and immerse one end of the magnet in acetone for a while, making sure that the acetone liquid level just covers the bonding position of the two magnets at the bottom with high-temperature glue 71, and remove the first magnet;

[0105] (6) Remove the remaining samarium cobalt magnets one by one according to the above method, ensuring that the magnets are not attracted to each other;

[0106] (7) Use non-magnetic tools to completely remove the high-temperature glue on the upper and lower surfaces of the 10 numbered samarium cobalt magnets;

[0107] (8) Clean the 10 numbered samarium cobalt magnets with alcohol;

[0108] (9) The center position surface magnetism of the 10 numbered samarium cobalt magnets was tested in turn. The results are shown in Table 3.

[0109] Table 3

[0110]

[0111] From the data in Table 3, it can be seen that after the stable magnetic aging of the samarium cobalt magnet, the surface magnetic loss of the N pole is in the range of 0.83% to 1.68%, and the surface magnetic loss of the S pole is in the range of 0.42% to 1.28%. The absolute value of the difference between the N pole and the S pole before and after the stable magnetic aging is reduced from 1mT to 6mT to 1mT to 5mT, and the average difference is reduced from 3.6mT to 2.9mT. Compared with Example 4, it can be seen that before and after the stable magnetic aging by placing the colloid adhesive fixed on the top, the surface magnetic attenuation of the N pole and the S pole is relatively large, and the absolute value of the surface magnetic difference between the N pole and the S pole changes greatly, which can achieve the effect of improving the consistency and symmetry of the surface magnetic. However, the stable magnetic aging method of placing the colloid adhesive fixed on the top cannot completely ensure the concentric placement of the magnet, and the disassembly and assembly are complicated, which cannot meet the demand of conveniently providing variable air gap field stable magnetic aging under batch conditions.

[0112] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0113] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for fixing a permanent magnet during magnetic aging, characterized in that: The fixing device used is used to fix the permanent magnet in the magnetized state for magnetic stabilization aging, and the fixing device includes: A mounting frame having a receiving cavity and an observation slot extending from an outer peripheral wall of the mounting frame to the receiving cavity; a cover body, detachably connected to the mounting frame and closing the opening of the storage cavity; an adjusting member connected to the cover body and extending into the receiving cavity, wherein the length of the adjusting member extending into the receiving cavity is adjustable; The receiving cavity is used to receive permanent magnets, and the adjusting member is used to push the permanent magnets in the receiving cavity to adjust the distance between adjacent permanent magnets. The fixing method comprises: placing the permanent magnets into the mounting frame in sequence from the opening of the receiving cavity, wherein the magnetic poles of the opposite ends of two adjacent permanent magnets are the same and the permanent magnets are in a magnetized state; Connecting the cover to the mounting frame and closing the opening of the storage cavity; The adjusting member is extended into the receiving cavity along the cover body, and the length of the adjusting member extended into the receiving cavity can be adjusted and pushed against the closest permanent magnet to adjust the distance between two adjacent permanent magnets; Placing the fixture in a heat treatment furnace and maintaining the temperature for a preset period of time; The fixture was cooled to room temperature in the furnace and then the permanent magnet was taken out.

2. The fixing method according to claim 1, characterized in that: The receiving cavity has a columnar cross section, and the cross-sectional dimension of the receiving cavity is slightly larger than the cross-sectional dimension of the permanent magnet.

3. The fixing method according to claim 1, characterized in that: The observation groove is linear, and an extending direction of the observation groove is parallel to a center line of the receiving cavity.

4. The fixing method according to claim 3, characterized in that: The mounting frame further includes scale lines arranged on the outer peripheral wall, and the scale lines are distributed along the length direction of the observation slot.

5. The fixing method according to claim 1, characterized in that: The mounting bracket further includes an auxiliary hole extending through the receiving cavity, wherein the auxiliary hole faces away from an opening direction of the receiving cavity.

6. The fixing method according to claim 1, characterized in that: The adjusting member is threadedly connected to the cover body, and a rotation center line of the adjusting member coincides with or is parallel to a center line of the receiving cavity.

7. The fixing method according to any one of claims 1 to 6, characterized in that: The mounting frame, the cover body and the adjusting member are all made of materials that are non-magnetic and have high thermal conductivity.

8. The fixing method according to claim 1, characterized in that: The step of adjusting the distance between two adjacent permanent magnets comprises: A Hall probe is used to measure the air gap field between two adjacent permanent magnets along the observation slot.

9. The fixing method according to claim 1, characterized in that: The number of the permanent magnets is greater than or equal to 3.

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