Method for nondestructive measurement of residual magnetism of permanent magnet magnetic shoe

Abstract

The invention discloses a method for nondestructive measurement of residual magnetism of a permanent magnet magnetic shoe. The method comprises the following steps: testing the volume of the magnetic shoe; calculating the magnetic flux of the magnetic shoe; testing the open-circuit magnetic flux Fp in the parallel orientation direction of the magnetic shoe and the open-circuit magnetic flux Fc in the vertical orientation direction of the magnetic shoe; calculating the magnetic flux F in the radial direction of the magnetic tile; calculating the magnetic flux per unit volume according to the magnetic flux F in the radial direction of the magnetic tile and the volume of the magnetic tile; calculating residual magnetism measurement Br: calculating the residual magnetism Br according to the relationship between the magnetic flux per unit volume of the magnetic shoe and the residual magnetism; in the process of obtaining the residual magnetism Br, a sample does not need to be manufactured, test data are easy to obtain, and the residual magnetism is calculated according to the test data, so that measurement of the residual magnetism of the permanent magnet magnetic shoe is completed, the method is simple and easy to operate, and nondestructive measurement of the residual magnetism of the magnetic shoe can be realized.

Description

Technical Field

[0001] The invention relates to the field of residual magnetism measurement of permanent magnet magnetic tiles, and in particular to a method for non-destructive residual magnetism measurement of permanent magnet magnetic tiles. Background Art

[0002] The main parameters characterizing the performance of permanent ferrite materials include residual magnetic induction intensity (Br), induced coercive force (Hcb), intrinsic coercive force (Hcj), magnetic energy product (BH), etc. The standard detection method commonly used in the industry is stipulated by GB / T 3217-1992 "Magnetic Test Methods for Permanent Magnetic (Hard Magnetic) Materials", which can be expressed as processing the permanent ferrite material into a cylindrical specimen with a rectangular or circular cross-section, and using a magnetic performance tester to test the hysteresis curve of the permanent magnetic material under different charging and demagnetizing magnetic fields. The curve in the second quadrant of the hysteresis curve (called the demagnetization curve) is often used to characterize the technical magnetic parameters of the permanent magnetic material. The national standard requires that the two end faces of the test specimen should be ground to be parallel to each other, with a parallelism not exceeding tolerance grade 9, the end face should be perpendicular to the axis, and the perpendicularity should not exceed tolerance grade 9. The cross-sectional area of ​​the specimen should remain consistent along the entire length, and its deviation should not exceed 1% of its minimum cross-sectional area. In actual production, it is common for performance testing to deviate because the sample processing accuracy does not meet national standards.

[0003] In the prior art, such as the method for measuring the residual magnetism of permanent ferrite magnetic tiles disclosed in Patent No. CN115825829A, the residual magnetism measurement requires that the permanent ferrite material be processed into a cylindrical sample with a rectangular or circular cross-section before the residual magnetism measurement can be performed. Summary of the invention

[0004] The purpose of the invention is to provide a method for non-destructive measurement of residual magnetism of permanent magnet magnetic tiles, which solves the problem that residual magnetism detection in the prior art requires sample preparation.

[0005] The present invention is implemented as follows: a method for non-destructive measurement of residual magnetism of a permanent magnet magnetic tile, the method comprising the following steps:

[0006] Step 1: Test the volume of magnetic tiles;

[0007] Step 2: Calculate the magnetic flux of the magnetic tile: test the open-circuit magnetic flux Fp in the direction parallel to the magnetic tile and the open-circuit magnetic flux Fc in the direction perpendicular to the magnetic tile; calculate the magnetic flux F in the radial direction of the magnetic tile;

[0008] Step 3, calculate the magnetic flux per unit volume of the magnetic tile: calculate the magnetic flux per unit volume according to the magnetic flux F in the radial direction of the magnetic tile and the volume of the magnetic tile;

[0009] Step 4: Calculate the residual magnetism Br: Based on the relationship between the magnetic flux per unit volume of the magnetic tile and the residual magnetism, calculate the residual magnetism Br.

[0010] In the prior art, the measurement of residual magnetism requires that the magnetic tile be made into a sample that meets the requirements. The preparation of the sample has certain requirements, which is easy to cause errors in the sample preparation stage, affecting the measurement result of the residual magnetism. In the present invention, there is no need to prepare the sample. Based on the conclusion that "when the Helmholtz coil and the fluxmeter remain unchanged, by testing the unit volume magnetic flux of a large number of samples, the proportional relationship between the residual magnetism Br of the sample and the unit volume magnetic flux can be summarized, such as Br≈unit volume magnetic flux*2109Gs", the residual magnetism of the ferrite magnetic tile is non-destructively measured. Specifically, the volume of the magnetic tile is tested, the Fp and Fc of the magnetic tile are tested, F is calculated according to Fp and Fc, and then the unit volume magnetic flux is calculated according to F and the volume of the magnetic tile. Finally, the residual magnetism Br is calculated according to the relationship between the unit volume magnetic flux of the magnetic tile and the residual magnetism. In the process of obtaining the residual magnetism Br, the present invention does not need to prepare the sample and the test data is easy to obtain. The residual magnetism is calculated according to the test data, thereby completing the measurement of the residual magnetism of the permanent magnet magnetic tile. The method is simple, easy to operate and can achieve non-destructive measurement of the residual magnetism of the magnetic tile.

[0011] A further technical solution of the present invention is: in the step 1, the volume of the magnetic tile is tested by the drainage method.

[0012] The volume of the magnetic tile is tested using the water displacement method, which is a known method for measuring volume that is easy to operate and is not restricted by conditions.

[0013] A further technical solution of the present invention is: in the step 2, the open-circuit magnetic flux Fp in the direction parallel to the orientation of the magnetic tile is tested: a magnetizing coil is used to magnetize the magnetic tile in the direction parallel to the orientation of the magnetic tile, and then the magnetized magnetic tile is placed in a Helmholtz coil, and the Helmholtz coil is connected to a fluxmeter to obtain the open-circuit magnetic flux Fp in the direction parallel to the orientation of the magnetic tile.

[0014] For the test of open-circuit magnetic flux in the direction parallel to the orientation of the magnetic tile, the present invention first requires a magnetizing coil to magnetize the magnetic tile in the direction parallel to the orientation of the magnetic tile, and the magnetized magnetic tile is placed in a Helmholtz coil, which is connected to the Helmholtz coil through a fluxmeter to obtain the Fp value; the equipment required for the measurement is simple, the method is easy to operate, and the measurement error is small.

[0015] A further technical solution of the present invention is: in the step 2, the open-circuit magnetic flux Fc in the vertical orientation direction of the magnetic tile is tested: the magnetic tile is fixed with a clamp, and the magnetic tile is magnetized in the vertical orientation direction with a magnetizing coil, and then the magnetized magnetic tile is placed in a Helmholtz coil, and the Helmholtz coil is connected to a fluxmeter to obtain the open-circuit magnetic flux Fc in the vertical orientation direction of the magnetic tile.

[0016] For the test of open-circuit magnetic flux in the vertical orientation direction of the magnetic tile, since the shape of the magnetic tile cannot be stabilized independently in the magnetizing coil, it is first necessary to use a clamp to fix it, and then magnetize and test it, and obtain Fc based on the results of the fluxmeter; the equipment required in this test process is simple and easy to obtain, and the operation method is also easy, with small measurement errors.

[0017] A further technical solution of the present invention is: in the step 2, the range of the fluxmeter used to test the open-circuit magnetic flux Fp in the direction parallel to the magnetic tile orientation is consistent with the range of the fluxmeter used to test the open-circuit magnetic flux Fc in the direction perpendicular to the magnetic tile orientation.

[0018] The measurement ranges used to measure Fp and Fc are consistent, which can further reduce measurement errors.

[0019] A further technical solution of the present invention is: in the step 2, F=(Fp*Fp+Fc*Fc)^0.5.

[0020] The final comprehensive open-circuit magnetic flux of the magnetic tile is F = (Fp*Fp+Fc*Fc)^0.5, which reflects the magnetic flux in the axial direction of the magnetic tile.

[0021] A further technical solution of the present invention is: in the step three, the magnetic flux per unit volume = the magnetic flux in the radial direction of the magnetic tile / the volume of the magnetic tile.

[0022] The magnetic flux per unit volume can be obtained by calculation based on the data obtained in steps one and two, and no measurement is required in step three.

[0023] A further technical solution of the present invention is: in the step 4, the remanence Br≈unit volume magnetic flux*2109Gs.

[0024] According to the relationship between the magnetic flux per unit volume and the remanence, the value of the remanence Br can be calculated, and there is no need to measure in step 4.

[0025] A further technical solution of the present invention is: the applicable scope of the method is that the induced coercive force (Hcb) of the magnetic tile is greater than the internal demagnetization field of the magnetic tile.

[0026] The beneficial effects of the present invention are as follows: in the present invention, it is not necessary to prepare samples, and based on the conclusion that "when the Helmholtz coil and the fluxmeter remain unchanged, by testing the unit volume magnetic flux of a large number of samples, the proportional relationship between the remanence Br of the sample and the unit volume magnetic flux can be summarized, such as Br≈unit volume magnetic flux*2109Gs", the residual magnetism of the ferrite magnetic tile is non-destructively measured; specifically, the volume of the magnetic tile is tested, the Fp and Fc of the magnetic tile are tested, F is calculated according to Fp and Fc, and then the unit volume magnetic flux is calculated according to F and the volume of the magnetic tile, and finally the residual magnetism Br is calculated according to the relationship between the unit volume magnetic flux of the magnetic tile and the residual magnetism; in the process of obtaining the residual magnetism Br, the present invention does not need to prepare samples and the test data is easy to obtain, and the residual magnetism is calculated according to the test data, thereby completing the measurement of the residual magnetism of the permanent magnet magnetic tile, and the method is simple, easy to operate and can realize non-destructive measurement of the residual magnetism of the magnetic tile. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow chart of a method for non-destructive measurement of residual magnetism of a permanent magnet magnetic tile provided by the present invention;

[0028] Figure 2 It is a structural schematic diagram of the permanent magnet magnetic tile provided by the present invention;

[0029] Figure 3 It is a test flow chart of the open-circuit magnetic flux Fp in the parallel orientation direction provided by the present invention;

[0030] Figure 4 It is a test flow chart of the open-circuit magnetic flux Fc in the vertical orientation direction provided by the present invention.

[0031] Figure numerals: 1. magnetic tile, 2. side limiter, 3. arch height limiter, 4. magnetizing coil, 5. pad, 6. Helmholtz coil, X. parallel orientation direction, Y. vertical orientation direction, Z. width direction. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0034] Embodiment 1:

[0035] Figure 1-4 A method for non-destructive measurement of residual magnetism of a permanent magnet magnetic tile is shown, the method comprising the following steps:

[0036] Step 1: Test the volume of magnetic tiles;

[0037] Step 2: Calculate the magnetic flux of the magnetic tile: test the open-circuit magnetic flux Fp in the direction parallel to the magnetic tile and the open-circuit magnetic flux Fc in the direction perpendicular to the magnetic tile; calculate the magnetic flux F in the radial direction of the magnetic tile;

[0038] Step 3, calculate the magnetic flux per unit volume of the magnetic tile: calculate the magnetic flux per unit volume according to the magnetic flux F in the radial direction of the magnetic tile and the volume of the magnetic tile;

[0039] Step 4: Calculate the residual magnetism Br: Based on the relationship between the magnetic flux per unit volume of the magnetic tile and the residual magnetism, calculate the residual magnetism Br.

[0040] In the prior art, the measurement of residual magnetism requires that the magnetic tile be made into a sample that meets the requirements. The preparation of the sample has certain requirements, which is easy to cause errors in the sample preparation stage, affecting the measurement result of the residual magnetism. In the present invention, there is no need to prepare the sample. Based on the conclusion that "when the Helmholtz coil and the fluxmeter remain unchanged, by testing the unit volume magnetic flux of a large number of samples, the proportional relationship between the residual magnetism Br of the sample and the unit volume magnetic flux can be summarized, such as Br≈unit volume magnetic flux*2109Gs", the residual magnetism of the ferrite magnetic tile is non-destructively measured. Specifically, the volume of the magnetic tile is tested, the Fp and Fc of the magnetic tile are tested, F is calculated according to Fp and Fc, and then the unit volume magnetic flux is calculated according to F and the volume of the magnetic tile. Finally, the residual magnetism Br is calculated according to the relationship between the unit volume magnetic flux of the magnetic tile and the residual magnetism. In the process of obtaining the residual magnetism Br, the present invention does not need to prepare the sample and the test data is easy to obtain. The residual magnetism is calculated according to the test data, thereby completing the measurement of the residual magnetism of the permanent magnet magnetic tile. The method is simple, easy to operate and can achieve non-destructive measurement of the residual magnetism of the magnetic tile.

[0041] In this embodiment, in step one, the volume of the magnetic tile is tested using a water displacement method.

[0042] The volume of the magnetic tile is tested by the water displacement method, which is a known method for measuring volume, easy to operate and not limited by conditions. Specifically, in this step, the permanent ferrite magnetic tile can be directly placed in a water-filled measuring cup, and then the magnetic tile is immersed in the measuring cup to observe the change of the water level in the measuring cup. Since the volume of the magnetic tile is the same as the volume of the water it displaces, the volume of the magnetic tile can be accurately known according to the change of the water level.

[0043] In this embodiment, the density of the magnetic tile is obtained by using a densitometer, the volume of the magnetic tile is obtained by using a water displacement method, and the mass of the magnetic tile can be obtained by weighing. The density of the magnetic tile is used to calibrate the data related to the magnetic tile.

[0044] In this embodiment, in the step 2, the open-circuit magnetic flux Fp in the direction parallel to the orientation of the magnetic tile is tested: the magnetic tile 1 is placed on the plastic pad 5, and the magnetizing coil 4 is used to magnetize the magnetic tile 1 in the direction parallel to the orientation X, and then the magnetized magnetic tile 1 is placed in the Helmholtz coil 6, and the Helmholtz coil 6 is connected to the fluxmeter to obtain the open-circuit magnetic flux Fp in the direction parallel to the orientation X of the magnetic tile.

[0045] For the test of open-circuit magnetic flux in the direction parallel to the orientation of the magnetic tile, the present invention first requires a magnetizing coil to magnetize the magnetic tile in the direction parallel to the orientation of the magnetic tile, and the magnetized magnetic tile is placed in a Helmholtz coil, which is connected to the Helmholtz coil through a fluxmeter to obtain the Fp value; the equipment required for the measurement is simple, the method is easy to operate, and the measurement error is small.

[0046] In this embodiment, the Helmholtz coil performs a magnetic flux test, and the test value is the magnetic flux parallel to the orientation direction. Figure 3 .

[0047] In this embodiment, in the step 2, the open circuit magnetic flux Fc in the vertical orientation direction of the magnetic tile is tested: the magnetic tile 1 is fixed with a plastic clamp, the clamp includes a side limiter 2 and an arch height limiter 3, the magnetic tile 1 is placed on a plastic pad, and the magnetizing coil 4 is used to magnetize the magnetic tile 1 in the vertical orientation direction Y, and then the magnetized magnetic tile 1 is placed in the Helmholtz coil 6, and the Helmholtz coil 6 is connected to the fluxmeter to obtain the open circuit magnetic flux Fc in the vertical orientation direction Y of the magnetic tile.

[0048] For the test of open-circuit magnetic flux in the vertical orientation direction of the magnetic tile, since the shape of the magnetic tile cannot be stabilized independently in the magnetizing coil, it is first necessary to use a clamp to fix it, and then magnetize and test it, and obtain Fc based on the results of the fluxmeter; the equipment required in this test process is simple and easy to obtain, and the operation method is also easy, with small measurement errors.

[0049] In this embodiment, the Helmholtz coil performs a magnetic flux test, and the test value is the magnetic flux perpendicular to the orientation direction. The schematic diagram of the method for testing the open-circuit magnetic flux of the magnetic tile perpendicular to the orientation direction is shown in Figure 4 .

[0050] In this embodiment, in step 2, the range of the fluxmeter used to test the open-circuit magnetic flux Fp in the direction X parallel to the magnetic tile orientation is consistent with the range of the fluxmeter used to test the open-circuit magnetic flux Fc in the direction Y perpendicular to the magnetic tile orientation.

[0051] The measurement ranges used to measure Fp and Fc are consistent, which can further reduce measurement errors.

[0052] In this embodiment, in step 2, F=(Fp*Fp+Fc*Fc)^0.5.

[0053] The final comprehensive open-circuit magnetic flux of the magnetic tile is F = (Fp*Fp+Fc*Fc)^0.5, which reflects the magnetic flux in the axial direction Z of the magnetic tile.

[0054] In this embodiment, the Fp test value is 9.69Wb, and the Fc value is 4.81Wb. According to F=(Fp*Fp+Fc*Fc)^0.5, it can be calculated that the magnetic flux F in the radial direction of the magnetic tile is 10.82Wb.

[0055] In this embodiment, in step three, the magnetic flux per unit volume = the magnetic flux in the radial direction of the magnetic tile / the volume of the magnetic tile.

[0056] The magnetic flux per unit volume can be obtained by calculation based on the data obtained in steps one and two, and no measurement is required in step three.

[0057] In this embodiment, in step 4, the remanence Br≈magnetic flux per unit volume*2109Gs.

[0058] According to the relationship between the magnetic flux per unit volume and the remanence, the value of the remanence Br can be calculated, and there is no need to measure in step 4.

[0059] The working principle of the present invention is as follows: in the present invention, it is not necessary to prepare samples, and based on the conclusion that "under the condition that the Helmholtz coil and the fluxmeter remain unchanged, by testing the unit volume magnetic flux of a large number of samples, the proportional relationship between the residual magnetism Br of the sample and the unit volume magnetic flux can be summarized, such as Br≈unit volume magnetic flux*2109Gs", the residual magnetism of the ferrite magnetic tile is non-destructively measured; specifically, the volume of the magnetic tile is tested, the Fp and Fc of the magnetic tile are tested, F is calculated according to Fp and Fc, and then the unit volume magnetic flux is calculated according to F and the volume of the magnetic tile, and finally the residual magnetism Br is calculated according to the relationship between the unit volume magnetic flux of the magnetic tile and the residual magnetism; in the process of obtaining the residual magnetism Br, the present invention does not need to prepare samples and the test data is easy to obtain, and the residual magnetism is calculated according to the test data, thereby completing the measurement of the residual magnetism of the permanent magnet magnetic tile, and the method is simple, easy to operate and can realize the non-destructive measurement of the residual magnetism of the magnetic tile.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for non-destructive measurement of residual magnetism of permanent magnet magnetic tiles, characterized in that: The method comprises the following steps: Step 1: Test the volume of magnetic tiles; Step 2: Calculate the magnetic flux of the magnetic tile: test the open-circuit magnetic flux Fp in the direction parallel to the magnetic tile and the open-circuit magnetic flux Fc in the direction perpendicular to the magnetic tile; calculate the magnetic flux F in the radial direction of the magnetic tile; Step 3, calculate the magnetic flux per unit volume of the magnetic tile: calculate the magnetic flux per unit volume according to the magnetic flux F in the radial direction of the magnetic tile and the volume of the magnetic tile; Step 4: Calculate the residual magnetism Br: Calculate the residual magnetism Br based on the relationship between the magnetic flux per unit volume of the magnetic tile and the residual magnetism.

2. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1 is characterized in that: In the step 1, the volume of the magnetic tile is tested by the drainage method.

3. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1 is characterized in that: In the step 2, the open-circuit magnetic flux Fp in the direction parallel to the orientation of the magnetic tile is tested: a magnetizing coil is used to magnetize the magnetic tile in the direction parallel to the orientation of the magnetic tile, and then the magnetized magnetic tile is placed in a Helmholtz coil, and the Helmholtz coil is connected to a fluxmeter to obtain the open-circuit magnetic flux Fp in the direction parallel to the orientation of the magnetic tile.

4. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1 is characterized in that: In the step 2, the open-circuit magnetic flux Fc in the vertical orientation direction of the magnetic tile is tested: the magnetic tile is fixed with a clamp, and the magnetic tile is magnetized in the vertical orientation direction with a magnetizing coil, and then the magnetized magnetic tile is placed in a Helmholtz coil, and the Helmholtz coil is connected to a fluxmeter to obtain the open-circuit magnetic flux Fc in the vertical orientation direction of the magnetic tile.

5. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1, characterized in that: In the step 2, the range of the fluxmeter used to test the open-circuit magnetic flux Fp in the direction parallel to the magnetic tile orientation is consistent with the range of the fluxmeter used to test the open-circuit magnetic flux Fc in the direction perpendicular to the magnetic tile orientation.

6. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1, characterized in that: In the step 2, F=(Fp*Fp+Fc*Fc)^0.

5.

7. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1, characterized in that: In the step three, the magnetic flux per unit volume = the magnetic flux in the radial direction of the magnetic tile / the volume of the magnetic tile.

8. The method for non-destructive measurement of residual magnetism of a permanent magnet tile according to claim 1, characterized in that: In the step 4, the remanence Br≈magnetic flux per unit volume*2109Gs.

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