Method and device for detecting magnetic performance of radial orientation permanent magnet ring

Abstract

The present application relates to a kind of radial orientation permanent magnet ring magnetic performance detection method and equipment, belong to permanent magnetic material testing field.The method aims at solving the problem that existing technology cannot accurately measure the real magnetic performance of radial orientation permanent magnet ring.The method includes: along the radial orientation permanent magnet ring radial cutting test sample of specified shape and recording its geometric and position parameters;Based on the volume average calculation correction coefficient K of magnetic moment projection in sample volume;Measure the initial demagnetization curve of sample;Apply K value point by point correction to obtain real demagnetization curve and key magnetic performance index.The equipment integrates sample clamping, magnetic field generation, magnetic measurement, control and acquisition, data processing and result display unit.The present application eliminates the problem of low measurement value caused by inconsistent grain orientation in sample by geometric correction, compatible with existing mainstream magnetic measurement equipment, provides reliable basis for quality control and standardized detection of radial orientation permanent magnet ring.

Description

Technical Field

[0001] This invention belongs to the field of magnetic property testing technology for permanent magnet materials, specifically relating to a method and equipment for testing the magnetic properties of radially oriented permanent magnet rings. Background Technology

[0002] Radially oriented permanent magnet rings are special configurations of permanent magnets with their easy magnetization axes arranged radially along the ring. They are widely used in magnetic encoders, magnetic sensors, and other fields. Because the easy magnetization axes of the internal grains are oriented radially, the orientation of grains at different radii varies even within the same radially oriented permanent magnet ring. Therefore, regardless of how a sample is cut from a radially oriented permanent magnet ring, it is difficult to obtain a test sample that is completely parallel to the magnetization axis and has the same magnetic moment. This makes it difficult for existing magnetic measuring instruments to accurately measure the true magnetic properties of radially oriented permanent magnet rings. For example, while vibrating sample magnetometers have high resolution, they require extremely small sample sizes to approximately maintain magnetic moment consistency. Using magnetic measuring instruments has lower sensitivity and requires larger sample sizes, at which point the error caused by differences in orientation at various points on the sample increases significantly. As a non-destructive testing method, fluxmeters (closed magnetic circuit method) cannot directly obtain meaningful test data for radially oriented permanent magnet rings magnetized in the radial direction, regardless of whether they are inner / outer pole or multi-pole rings.

[0003] Currently, there are no specific international, national, or industry standards for radially oriented permanent magnet rings. According to reports, manufacturers can only conduct magnetic performance testing according to their own internal standards. Summary of the Invention

[0004] This invention provides a method and device for detecting the magnetic properties of radially oriented permanent magnet rings, aiming to solve one of the problems in existing equipment and methods, such as sampling errors caused by the radial distribution of the easy magnetization axis of the grains in radially oriented permanent magnet rings, as well as low measurement values, poor consistency, and the lack of specific international, national, or industry standards for the magnetic detection of rare earth radially oriented permanent magnet rings.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for detecting the magnetic properties of a radially oriented permanent magnet ring, comprising the following steps: S1: Sample from the radially oriented permanent magnet ring to be tested using a radial method, and record the geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring to be tested; S2: Calculate the correction coefficient K based on the sample's geometric dimensions and positional parameters; S3: Initial demagnetization curve of the test sample; S4: Based on the initial demagnetization curve, obtain the magnetization intensity M. 测量 The true magnetization M is calculated based on the correction factor K. 真实M 真实 = M 测量 / K, after correction, M 真实 -H i curve; S5: Utilizing the actual magnetization M 真实 and the applied magnetic field strength H i Based on the correspondence, the magnetic induction intensity B of the sample is calculated. 真实 To obtain the true B 真实 -H i curve.

[0006] Further, in S1, the sample is a cylinder or a cuboid. The axis of the cylinder is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the normal direction of the radially oriented permanent magnet ring to be tested is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the tangent direction of the radially oriented permanent magnet ring to be tested is parallel to the axis of the radially oriented permanent magnet ring to be tested.

[0007] Furthermore, the geometric dimensions of the cylinder include diameter D, height H, and the shortest distance h1 from the lower surface of the cylinder to the axis of the radially oriented permanent magnet ring to be tested.

[0008] The geometric dimensions of the cuboid include the tangential length L along the radial orientation permanent magnet ring to be tested, the radial width W along the radial orientation permanent magnet ring to be tested, the normal thickness T along the radial orientation permanent magnet ring to be tested, and the shortest distance h2 from the lower surface of the cuboid to the axis of the radial orientation permanent magnet ring to be tested.

[0009] And / or, the position parameters include establishing a coordinate system with the geometric center of the radially oriented permanent magnet ring to be tested as the origin, wherein the radial direction of the radially oriented permanent magnet ring is the y-axis, the tangential direction is the x-axis, and the normal direction is the z-axis.

[0010] Furthermore, in S2, the correction coefficient K is determined through the following integral relationship:

[0011] Where V is the volume of the sample. ( , ) is the angle between a point at any position (x, y) on the sample and the radial direction of the radially oriented permanent magnet ring to be tested and the normal direction of the radially oriented permanent magnet ring.

[0012] Furthermore, in S3, the initial demagnetization curve is measured by one of the following: a permanent magnet magnetic measuring instrument, a permanent magnet pulse measuring instrument, or a vibrating sample magnetometer.

[0013] Furthermore, in S4, according to the corrected M 真实 -Hi The curve yields the remanent magnetization. Innate self-control Knee point magnetic field .

[0014] Furthermore, in S5, based on the real B 真实 -H i The curve yields the coercivity H. cB and maximum magnetic energy product BH max .

[0015] Furthermore, sampling in S1 includes wire cutting, grinding, or other machining methods that do not alter the magnetism of the material.

[0016] On the other hand, the present invention provides a radially oriented permanent magnet ring magnetic property detection device for any of the above-described methods, comprising: The sample clamping mechanism is used to fix the sample to be tested and ensure that at least one axis of the sample to be tested is aligned with the direction of the magnetic field applied during the test. A magnetic field generating unit is used to provide an external magnetic field; Magnetic measurement unit, used for applying an external magnetic field strength H i The magnetic response of the sample under test is measured and the measurement data, magnetization M, is output. 测量 ; The control and acquisition unit is used to control the magnetic field generating unit to operate according to a predetermined magnetic field sequence and to synchronously sample the magnetic measurement unit to obtain a complete initial demagnetization curve and obtain the magnetization intensity M. 测量 and the corresponding H i value; The data processing and automatic calibration unit is used to calculate the correction coefficient K based on the sample's geometric dimensions and position parameters on the radially oriented permanent magnet ring under test, and to calculate the true magnetization M based on the correction coefficient K. 真实 After obtaining the correction M 真实 -H i The curve uses the actual magnetization M 真实 and the applied magnetic field strength H i The correspondence is obtained to obtain the true B. 真实 -H i curve; The results display unit is used to initially measure the demagnetization curve and the corrected M. 真实 -H i The curve is displayed, and the magnetic property parameters before and after correction are shown simultaneously.

[0017] Furthermore, it also includes methods for storing the initial demagnetization curve, correction function, and corrected M. 真实 -H i The storage unit for the curve.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method of this invention calculates the correction coefficient K based on the geometric dimensions and position parameters of the sampled specimen, and corrects the initial demagnetization curve point by point, thereby restoring the complete and true demagnetization curve (including M) of the radially oriented permanent magnet ring. 真实 -H i With B 真实 - H i The curve was used to calculate key magnetic performance indicators. For the first time, the sampling direction difference was transformed into a quantifiable correction coefficient K (which is only related to the sample geometry and position and is independent of the applied magnetic field). M was applied point by point to the initial demagnetization curve. 真实 = M 测量 / K reverse compensation accurately reconstructs the complete true M from a single sample and a single measurement. 真实 -H i With B 真实 - H i The curves were obtained, and key performance indicators were derived, which completely solved the problem that the measured values ​​were systematically low and there were no standards to follow due to the dispersion of grain orientation in traditional methods.

[0019] 2. This invention corrects the measurement results of samples along the radial direction through mathematical integration. It calculates the projection of the magnetic moment deviating from the measurement axis along the measurement axis and performs mathematical integration. This mathematical approach eliminates the problem of low measurement values ​​caused by orientation differences, enabling the acquisition of true B values ​​suitable for engineering and quality control. 真实 - H i Curve. Using the method of this invention, the true remanence, coercivity, and maximum energy product of radially oriented permanent magnet rings can be accurately calculated from the measured sample magnetic data. This provides a reliable basis for the quality control and product standardization of radially oriented permanent magnet rings, significantly improving the accuracy and consistency of the magnetic performance evaluation. Simultaneously, it enhances the standardization and repeatability of radially oriented permanent magnet ring testing, possessing advantages such as high accuracy, strong practicality, and good compatibility, facilitating quality control and standardized testing.

[0020] 3. The device of the present invention integrates a sample clamping mechanism, a magnetic field generating unit, a magnetic measurement unit, a control and acquisition unit, a data processing and automatic calibration unit, and a result display unit. The device as a whole achieves high accuracy—orientation deviation is eliminated through a geometric projection integral model system; good compatibility—the sample clamping mechanism and data processing unit are pre-set with both cuboid and cylindrical models to adapt to radially oriented permanent magnet rings of different specifications; and high automation—the entire process from magnetic field sequence control and data acquisition to calibration calculation and result display is executed automatically, greatly improving detection efficiency and repeatability, and providing reliable device support for the quality control and standardized testing of radially oriented permanent magnet rings.

[0021] 4. The device of the present invention also includes an interface for inputting sample information and for saving the initial demagnetization curve, correction function, and corrected M. 真实 -H i The curve storage unit enables complete traceability and batch management of detection data, meeting the requirements of the quality management system for record traceability. It also supports multi-sample statistical analysis and model iterative optimization, upgrading the device from a measurement tool to a data management platform, further improving compensation accuracy.

[0022] To more clearly illustrate the technical solutions involved in the embodiments of the present invention or the prior art, the accompanying drawings included in the description of the embodiments or the prior art will be briefly introduced below. It should be noted that these drawings only show some specific embodiments recorded in the present invention and do not cover all possible implementations.

[0023] Figure Labels Figure 1 A schematic diagram showing the arrangement of easy magnetization axes of grains within a permanent magnet ring sample column with different diameters and radial orientations; Figure 2 This is a schematic diagram of a radially oriented permanent magnet ring and a rectangular sample cut along the radial direction. Detailed Implementation

[0024] The technical solution of the present invention will now be described in detail and comprehensively. It should be noted that the embodiments described are only a part of the present invention and do not cover all embodiments. Furthermore, all other embodiments that can be obtained by those skilled in the art based on the embodiments provided by the present invention without creative effort should also fall within the protection scope of the present invention. In the following embodiments, unless otherwise specified, the instruments and materials used are commercially available.

[0025] Because the easy magnetization axes of the grains inside the radially oriented permanent magnet ring are distributed radially along the radial direction, such as Figure 1As shown, any finite-sized sample cut from the ring cannot achieve perfectly parallel and consistent internal magnetic moment directions. This leads to a systematic underestimation of the demagnetization curves obtained by traditional magnetic measurement equipment (such as vibrating sample magnetometers, magnetic measuring instruments, and closed-circuit fluxmeters), failing to reflect the true magnetic properties of the material. Specifically, vibrating sample magnetometers require extremely small sample sizes to approximate magnetic moment consistency, but this is difficult to manufacture and results in poor signal-to-noise ratio. Magnetic measuring instruments have low sensitivity, and increasing the sample size exacerbates errors caused by orientation differences. The closed-circuit method cannot obtain meaningful measurement data for radially magnetized radially oriented permanent magnet rings. Furthermore, there are currently no dedicated standards for testing the magnetic properties of radially oriented permanent magnet rings, both domestically and internationally. Manufacturers can only rely on internal methods for quality control, lacking unified and accurate testing methods. Theoretically, while the true performance can be obtained by processing a series of sample columns with different diameters and extrapolating to a diameter of zero, this method requires the preparation of multiple samples, is highly destructive, cumbersome, and involves uncertainties in the extrapolation.

[0026] This invention, through extensive experimentation, has discovered that the actual magnetic properties of radially oriented permanent magnet rings can be obtained using the following method: A series of test samples of different diameters are machined along the radial direction of a radially oriented permanent magnet ring, and their magnetic properties are measured separately. This data is then plotted as a curve, and the curve is extended to the point where the sample diameter equals 0, thus yielding the true magnetic properties of the radially oriented permanent magnet ring. From this, it can be deduced that if a test sample of arbitrary diameter is cut along the radial direction of the radially oriented permanent magnet ring, the magnetic properties of the radially oriented permanent magnet ring obtained using this sample will be lower than the actual magnetic properties of the radially oriented permanent magnet ring. Therefore, there is an urgent need for a method and equipment that can accurately compensate for differences in the sampling direction of radially oriented permanent magnet rings and rapidly obtain their true magnetic properties to meet the needs of high-performance radially oriented permanent magnet ring development and testing.

[0027] To address the detection error problem caused by the radial distribution of the easy magnetization axis of the grains in radially oriented permanent magnet rings in existing technologies, this invention proposes a method and supporting detection device for detecting the magnetic properties of radially oriented permanent magnet rings. This method involves strictly defining the sample shape, recording the sample's geometric dimensions and position parameters on the radially oriented permanent magnet ring under test, and calculating correction coefficients. The initial demagnetization curve was corrected point by point to restore the complete and true demagnetization curve of the radially oriented permanent magnet ring (including M). 真实 -H i With B 真实 -H i The curve is used to calculate magnetic property parameters (such as remanent magnetization, intrinsic coercivity, knee magnetic field, and coercivity H). cB and maximum magnetic energy product BH max ).

[0028] A specific embodiment of the present invention discloses a method for detecting the magnetic properties of a radially oriented permanent magnet ring, comprising the following steps: S1: Sample from the radially oriented permanent magnet ring to be tested using a radial method, and record the geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring to be tested; S2: Calculate the correction coefficient K based on the sample's geometric dimensions and positional parameters; S3: Initial demagnetization curve of the test sample; S4: Based on the initial demagnetization curve, obtain the magnetization intensity M. 测量 The true magnetization M is calculated based on the correction factor K. 真实 M 真实 = M 测量 / K, after correction, M 真实 -H i curve; S5: Utilizing the actual magnetization M 真实 and the applied magnetic field strength H i Based on the correspondence, the magnetic induction intensity B of the sample is calculated. 真实 To obtain the true B 真实 -H i curve.

[0029] The method of this invention calculates the correction coefficient K based on the geometric dimensions and position parameters of the sampled specimen, and corrects the initial demagnetization curve point by point, thereby restoring the complete and true demagnetization curve (including M) of the radially oriented permanent magnet ring. 真实 -H i With B 真实 - H i The curve was used to calculate key magnetic performance indicators. For the first time, the difference in sampling direction was transformed into a quantifiable correction coefficient K (which is only related to the sample's geometry and position and is independent of the applied magnetic field). M was applied point by point to the initial demagnetization curve. 真实 = M 测量 / K reverse compensation accurately reconstructs the complete true M from a single sample and a single measurement. 真实 -H i With B 真实 - H i The curves were obtained, and key performance indicators were derived, which completely solved the problem that the measured values ​​were systematically low and there were no standards to follow due to the dispersion of grain orientation in traditional methods.

[0030] Furthermore, the geometric dimensions of the cylinder include diameter D, height H, and the shortest distance h1 from the lower surface of the cylinder to the axis of the radially oriented permanent magnet ring to be measured.

[0031] The geometric dimensions of the cuboid include the tangential length L along the radial orientation permanent magnet ring to be tested, the radial width W along the radial orientation permanent magnet ring to be tested, the normal thickness T along the radial orientation permanent magnet ring to be tested, and the shortest distance h2 from the lower surface of the cuboid to the axis of the radial orientation permanent magnet ring to be tested.

[0032] And / or, the position parameters include establishing a coordinate system with the geometric center of the radially oriented permanent magnet ring to be measured as the origin, the radial direction of the radially oriented permanent magnet ring as the y-axis, the tangential direction as the x-axis, and the normal direction as the z-axis.

[0033] Step S1 involves sample preparation and recording of the geometric dimensions and position parameters of the test sample within the radially oriented permanent magnet ring. Standardized sampling shape and precise geometric positioning provide unique and reproducible input parameters for subsequent calibration coefficient calculations, eliminating dimensional and positional uncertainties caused by arbitrary sample cutting, thus laying the physical foundation for the calibration model. Simultaneously, this step directly complements Step S2 (calibration coefficient K calculation)—only with accurate D, H, L, W, T, and h parameters can accurate calculations be achieved. 1、 Only with the h2 parameter can the integration operation in step S2 yield the correct K value.

[0034] Further, in S1, the sample is a cylinder or a cuboid. The axis of the cylinder is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the normal direction of the radially oriented permanent magnet ring to be tested is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the tangent direction of the radially oriented permanent magnet ring to be tested is parallel to the axis of the radially oriented permanent magnet ring to be tested.

[0035] First, the sample is explicitly defined as a cylinder or cuboid, and its rotational symmetry axis (the axis of the cylinder, and the axis parallel to the normal of the cuboid) must be consistent with the magnetic orientation direction (radial) of the radial ring. This ensures from the outset that the overall orientation of the easy magnetization axis of the grains within the sample is basically aligned with the direction of the magnetic field applied in subsequent measurements. This controls the sampling direction difference within a correctable geometric projection framework, avoiding the problem of excessive orientation deviation caused by arbitrary sample cutting, which cannot be compensated by a unified correction coefficient. It provides standardized input parameters for the subsequent geometric projection averaging correction model, making it consistent and comparable between different operators and different batches of samples. This significantly improves the repeatability and standardization of the detection method, laying the physical foundation for accurate, rapid, and consistent detection of the radial ring's magnetic properties.

[0036] Furthermore, sampling in step S1 includes wire cutting, grinding, or other machining methods that do not alter the magnetic properties of the material.

[0037] The sampling in step S1 includes wire cutting, grinding, or other mechanical processing methods that do not alter the material's magnetism, ensuring the end face is flat and perpendicular. This invention limits sample cutting to mechanical methods that do not change the magnetism, ensuring that the magnetic properties of the sample are not affected by heat or stress during preparation, guaranteeing the authenticity of the original measurement data. It also provides multiple feasible processing paths, enhancing the method's operability and providing a basis for establishing specific international, national, or industry standards for rare-earth permanent magnet radially oriented permanent magnet rings.

[0038] Furthermore, in S2, the correction coefficient K is determined through the following integral relationship: ; Where V is the volume of the sample. ( , Let y be a point at any position (x, y) on the sample, and the angle between the radial direction of the radially oriented permanent magnet ring to be tested and the normal direction of the radially oriented permanent magnet ring.

[0039] Specifically, step S2 involves establishing a coordinate system and calculating the correction coefficient K. A coordinate system is established with the center of the radially oriented permanent magnet ring as the origin: the radial direction of the radially oriented permanent magnet ring is the y-axis, the tangential direction is the x-axis, and the normal direction is the z-axis. Based on the geometric dimensions of the test sample and its position parameters within the radially oriented permanent magnet ring recorded in step S1, the correction coefficient K is calculated. K is defined as the angle between the radial direction of the radially oriented permanent magnet ring under test and the normal direction of the radially oriented permanent magnet ring. The volume average of the cosine value, i.e. The K value reflects the proportionality coefficient between the measured magnetization and the true magnetization caused by the dispersion of internal grain orientation in the sample. Under the assumption of this method (uniform macroscopic response of the material), K is independent of the applied magnetic field. The sample's geometric information is transformed into a quantitative correction factor independent of the material's intrinsic magnetism, thus converting the physical sampling bias problem into a purely geometric projection problem. This step is independent of and parallel to step S3 (initial measurement of the demagnetization curve)—the calculation of K does not depend on the measurement process and can be completed offline before or after the measurement; simultaneously, the accuracy of the K value directly affects the correction accuracy of step S4 and is a crucial parameter for the entire correction process.

[0040] This invention corrects the measurement results of samples along the radial direction through mathematical integration. It calculates the projection of the magnetic moment deviating from the measurement axis along the measurement axis and performs mathematical integration. This mathematical approach eliminates the problem of underestimating measurements caused by orientation differences, enabling the acquisition of true B-values ​​suitable for engineering and quality control. 真实 - H iCurve. Using the method of this invention, the true remanence, coercivity, and maximum energy product of radially oriented permanent magnet rings can be accurately calculated from the measured sample magnetic data. This provides a reliable basis for the quality control and product standardization of radially oriented permanent magnet rings, significantly improving the accuracy and consistency of the magnetic performance evaluation. Simultaneously, it enhances the standardization and repeatability of radially oriented permanent magnet ring testing, possessing advantages such as high accuracy, strong practicality, and good compatibility, facilitating quality control and standardized testing.

[0041] Furthermore, the initial demagnetization curve is measured using one of the following methods: a permanent magnet magnetic measuring instrument, a permanent magnet pulse measuring instrument, or a vibrating sample magnetometer.

[0042] Specifically, step S3: Measure the initial demagnetization curve. Using a permanent magnet magnetometer, a permanent magnet pulse meter, and a vibrating sample magnetometer, perform a magnetization-demagnetization procedure on the sample: control the magnetic field generating unit to gradually apply the external magnetic field H according to a set sequence. i (i=1,2,…,N), in each Magnetization M of the sample collected 测量 Record the corresponding H i This step generates a discrete data sequence of initial demagnetization curves. It utilizes general-purpose magnetic measurement equipment to acquire the raw measurement data of the sample, requiring no hardware modifications and ensuring the broad compatibility and practicality of the method. This step works in conjunction with step S2—M in the initial demagnetization curve... 测量 The apparent value that needs to be corrected subsequently is precisely the K value provided in step S2, which eliminates the deviation between the apparent value and the true value. Meanwhile, the measurement process in step S3 is independent of the calculation of K, allowing both to be executed in parallel and shortening the overall detection cycle.

[0043] Furthermore, in S4, according to the corrected M 真实 -H i The curve yields the remanent magnetization. Innate self-control Knee point magnetic field .

[0044] Furthermore, in S5, based on the real B 真实 -H i The curve yields the coercivity H. cB and maximum magnetic energy product BH max .

[0045] Specifically, step S4: Point-by-point correction to obtain the true M 真实 -H i The curve and magnetic properties are obtained from each sampling point measured in step S3. H i The corresponding M 测量The correction coefficient K obtained from step S2 is applied according to formula M. 真实 = M 测量 / K point-by-point correction yields the curve of the true magnetization of the radially oriented magnetic ring material as a function of the applied magnetic field (M 真实 -H i (Curve). Based on this, the magnetic property parameters are extracted: remanent magnetization. Innate self-control Knee point magnetic field This step, by using a constant K independent of the magnetic field, to proportionally amplify the entire demagnetization curve, systematically eliminates the measurement error caused by inconsistent grain orientation within the sample, thus obtaining for the first time the true magnetic property parameters of radially oriented permanent magnet ring materials from a finite-size sample. This step is related to step S5 (calculating B). 真实 -H i (Curve and magnetic properties) Direct connection - after correction It is to calculate the magnetic induction intensity B 真实 The necessary input is to first obtain an accurate M. 真实 -H i Only through relationships can we further derive accurate B. 真实 -H i Curve and remanent magnetization Innate self-control Knee point magnetic field Coercivity H cB and maximum magnetic energy product BH max parameter.

[0046] Specifically, the key magnetic performance indicators in step S5 include coercivity H. cB and maximum energy product (BH) max Magnetic property parameters. The actual B is derived in step S5. 真实 - H i Curve and actual magnetic performance parameters, using the actual demagnetization curve M obtained in step S4. 真实 -H i With the applied magnetic field strength H i The correspondence is based on the fundamental magnetic relation B under the International System of Units. 真实 = i +M 真实 Calculate the magnetic induction intensity B point by point. 真实 - H i Thus obtaining the complete (B) 真实 - H i (Curve). From this curve, the magnetic properties are obtained: coercivity H cB and maximum magnetic energy product BH maxFinally, the original preliminary curve, the corrected true curve, and the performance parameters before and after correction are displayed in the results display unit and can be saved to the storage unit for traceability and analysis. This step converts the magnetization data into directly usable magnetic induction intensity parameters, completing the full mapping from the intrinsic properties of the material to the apparent properties of the device, and providing a criterion for the standardized testing of the magnetic properties of radially oriented permanent magnet rings.

[0047] This invention covers the entire process from sample cutting, geometric parameter recording, coordinate system establishment, correction coefficient K calculation, initial demagnetization curve measurement, to point-by-point correction to obtain M. 真实 -H i This invention, through the entire process of curve analysis, achieves for the first time the technical effect of restoring the true value from the lower measured value. By utilizing the physical understanding of geometric projection averaging, it transforms the sampling error, which was originally considered unavoidable, into a precisely calculable correction coefficient. This coefficient is then used to perform point-by-point reverse compensation on the measurement data, thereby accurately reconstructing the true demagnetization curve and magnetic properties of the radially oriented permanent magnet ring from the measured values ​​of a sample of finite size. This completely solves the problems of traditional methods, such as systematically lower measured values ​​and poor consistency due to grain orientation dispersion, and the lack of specific international, national, or industry standards for the magnetic detection of rare-earth radially oriented permanent magnet rings.

[0048] Compared with existing technologies, this invention corrects the measurement results of radial ring samples through mathematical integral correction, systematically eliminating the measurement underestimation error caused by radial orientation, and obtaining true B values ​​suitable for engineering and quality control. 真实 - H i Curve. Using the method of this invention, the true remanence, coercivity, and maximum energy product of radially oriented permanent magnet rings can be accurately calculated from the measured sample magnetic data, thus providing a reliable basis for the quality control and product standardization of radially oriented permanent magnet rings. It significantly improves the accuracy and consistency of the magnetic performance evaluation of radially oriented permanent magnet rings. At the same time, it enhances the standardization and repeatability of radially oriented permanent magnet ring testing, possessing advantages such as high accuracy, strong practicality, and good compatibility, facilitating quality control and standardized testing.

[0049] On the other hand, the present invention provides a radially oriented permanent magnet ring magnetic property detection device according to the above method, comprising: The sample clamping mechanism is used to fix the sample to be tested and ensure that at least one axis of the sample to be tested is aligned with the direction of the magnetic field applied during the test. A magnetic field generating unit is used to provide an external magnetic field; Magnetic measurement unit, used for applying an external magnetic field strength H i The magnetic response of the sample under test is measured and the measurement data, magnetization M, is output. 测量 ; The control and acquisition unit is used to control the magnetic field generating unit to operate according to a predetermined magnetic field sequence and to synchronously sample the magnetic measurement unit to obtain a complete initial demagnetization curve and obtain the magnetization intensity M. 测量 and the corresponding H i value; The data processing and automatic calibration unit is used to calculate the correction coefficient K based on the geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring under test, and to calculate the true magnetization M based on the correction coefficient K. 真实 After obtaining the correction M 真实 -H i The curve uses the actual magnetization M 真实 and the applied magnetic field strength H i The correspondence is obtained to obtain the true B. 真实 -H i curve; The results display unit is used to initially measure the demagnetization curve and the corrected M. 真实 -H i The curve is displayed, and the magnetic property parameters before and after correction are shown simultaneously.

[0050] Specifically, the present invention provides a radially oriented permanent magnet ring magnetic property testing device, comprising: A) a sample clamping mechanism for fixing a test sample cut from the radially oriented permanent magnet ring along the radial direction, and ensuring that at least one axis of the test sample is aligned with the direction of the magnetic field applied during the test; The sample clamping mechanism ensures that at least one axis of the sample is aligned with the direction of the applied magnetic field during testing. This allows the correction coefficient K, calculated subsequently based on the geometric projection averaging model, to accurately reflect the true orientation and dispersion of the grains within the sample. If there is a deviation between the sample axis and the magnetic field direction, the initial demagnetization curve will contain not only the intrinsic orientation and dispersion information of the sample but also additional projection components caused by clamping errors. This leads to the failure of the correction model and a deviation of the corrected result from the true value. Therefore, this feature significantly improves the repeatability and correction accuracy of the measurement process, providing a crucial prerequisite for accurately reproducing the true magnetic properties from a single sample and a single measurement. It also ensures good consistency and comparability of test results from different operators and different batches, meeting the requirements of standardized testing.

[0051] A magnetic field generating unit is used to provide a controllable external magnetic field to the test sample during measurement. The magnetic field generating unit includes at least one of the following components: a controllable electromagnet (including a coil and a magnetic core), a combination of a movable permanent magnet, or a drivable hybrid magnetic source structure. The magnetic field generating unit is capable of generating a magnetizing-demagnetizing magnetic field sequence according to a preset program or instructions issued by a control module.

[0052] Magnetic measurement unit, used for applying an external magnetic field strength H iThe magnetic response of the sample under test is measured and the measurement data, magnetization M, is output. 测量 The magnetic measurement unit employs at least one of the following measurement methods to achieve its measurement function: a vibrating sample magnetometer; a magnetic flux measurement component based on electromagnetic induction, including a fluxmeter and / or a detection coil, for acquiring the magnetic flux or induced voltage passing through the detection coil; a magnetic flux comparator based on the closed magnetic circuit method; or a solid-state sensor array based on the Hall effect or magnetoresistive effect; and the magnetic measurement unit further includes multiple sampling and signal conditioning paths corresponding to the measurement methods, and the magnetic measurement unit is configured to switch to the corresponding sampling and signal conditioning path for signal processing according to the currently adopted measurement method.

[0053] The control and acquisition unit is used to control the magnetic field generating unit to operate according to a predetermined magnetic field sequence and to synchronously sample the magnetic measurement unit to obtain a complete initial demagnetization curve with magnetization M. 测量 and the corresponding applied magnetic field strength H i value.

[0054] The data processing and automatic calibration unit is used to automatically calculate the correction coefficient based on the geometric dimensions, sampling location and orientation information of the test sample, and to correct the initial demagnetization curve point by point to obtain the true demagnetization curve of the radial ring material and further obtain magnetic performance parameters such as remanence, coercivity and maximum energy product.

[0055] The results display unit is used to initially measure the demagnetization curve and the corrected M. 真实 -H i The curve is displayed, and the magnetic property parameters before and after correction are shown simultaneously.

[0056] The above units together constitute a complete radial orientation permanent magnet ring magnetic performance detection device. Its coordination can be summarized as follows: (1) The sample clamping mechanism + magnetic field generation unit + magnetic measurement unit + control and acquisition unit constitute the "physical measurement link", which is responsible for obtaining the original M 测量 (2) The data processing and automatic calibration unit uses the provided geometric and positional parameters, the measurement data provided by the magnetic measurement unit and the control and acquisition unit to obtain the true magnetic properties through the K-value integral relationship; (3) The result display unit presents and saves the results before and after calibration intuitively. The device as a whole achieves high accuracy - the orientation deviation is eliminated through the geometric projection integral model system; good compatibility - the sample clamping mechanism and the data processing unit are pre-set with two models, cuboid and cylinder, to adapt to radially oriented permanent magnet rings of different specifications; high degree of automation - the entire process from magnetic field sequence control, data acquisition to calibration calculation and result display is automatically executed, which greatly improves the detection efficiency and repeatability, and provides reliable device support for the quality control and standardized detection of radially oriented permanent magnet rings.

[0057] The device of this invention integrates a sample clamping mechanism, a magnetic field generating unit, a magnetic measurement unit, a control and acquisition unit, a data processing and automatic calibration unit, and a result display unit. The device achieves high accuracy—orientation deviation is eliminated through a geometric projection integral model system; good compatibility—the sample clamping mechanism and data processing unit are pre-set with both cuboid and cylindrical models to accommodate radially oriented permanent magnet rings of different specifications; and high automation—the entire process, from magnetic field sequence control and data acquisition to calibration calculation and result display, is executed automatically, significantly improving detection efficiency and repeatability, and providing reliable device support for the quality control and standardized testing of radially oriented permanent magnet rings.

[0058] Furthermore, it also includes an interface for inputting sample information, as well as a method for saving the initial demagnetization curve, correction function, and corrected M. 真实 -H i The storage unit for the curve.

[0059] Specifically, this invention adds a storage unit, enabling complete traceability and batch management of test data, meeting the record traceability requirements of the quality management system. It also supports multi-sample statistical analysis and model iterative optimization, upgrading the device from a measurement tool to a data management platform, further improving compensation accuracy. Specifically, the sample information input interface allows operators to record metadata such as the batch, model, and sampling location of the radially oriented permanent magnet ring under test, while the storage unit archives and saves the initial demagnetization curve, the calculation process of the correction coefficient K, the corrected actual demagnetization curve, and performance indicators. First, a complete test data chain is constructed—from sample identity, geometric parameters, and original measurements to the correction model and final results, all are traceable, facilitating subsequent quality audits, process analysis, and problem troubleshooting. Second, it supports multi-sample statistical analysis and model iterative optimization—through batch storage of magnetic performance data before and after correction, the performance consistency of different batches of products can be evaluated. The device of this invention also includes an interface for sample information input and a method for saving the initial demagnetization curve, correction function, and corrected M... 真实 -H i The curve storage unit enables complete traceability and batch management of detection data, meeting the requirements of the quality management system for record traceability. It also supports multi-sample statistical analysis and model iterative optimization, upgrading the device from a measurement tool to a data management platform, further improving compensation accuracy.

[0060] Furthermore, the magnetic measurement unit adopts a closed magnetic circuit structure that conforms to industry / national magnetic testing standards or a precision testing instrument that can output a complete BH curve.

[0061] This invention specifies that the magnetic detection unit should employ a closed magnetic circuit structure conforming to national / industry standards or a precision instrument capable of outputting a complete BH curve. This directly solves the technical problem of the lack of specific standards for radially oriented permanent magnet rings in rare earth permanent magnets, ensuring the legal validity and industry interoperability of the original data. Furthermore, this invention represents an intelligent upgrade of existing standard equipment, achieving accurate measurement of the true magnetic properties of radially oriented permanent magnet rings without abandoning existing standard equipment, significantly lowering the industrialization threshold. Data obtained from a closed magnetic circuit structure conforming to industry / national magnetic testing specifications or from a precision detection instrument capable of outputting a complete BH curve has legal validity and industry interoperability, and can be directly used for product factory inspection, quality arbitration, and third-party certification, avoiding errors caused by measurement methods deviating from standards.

[0062] In summary, the correction principle of this invention is as follows: Under a unified coordinate system (with the geometric center as the origin, the radial direction of the radially oriented permanent magnet ring as the y-axis, the tangential direction as the x-axis, and the normal direction as the z-axis), the correction coefficient is defined as the normalized average of the volume integral or area integral of the local magnetic moment projected radially (or the cosine factor over the projected area) within the sample volume; under the approximation of the macroscopic uniform response of the material, K can be calculated using the volume average (or area average) expression. This correction is applied point-by-point to the measured demagnetization curve, achieving point-by-point correction of the entire demagnetization process. Detection process: This invention specifies that the test sample cut radially from the radially oriented permanent magnet ring is a cylinder or cuboid. The geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring to be tested are recorded. The initial demagnetization curve is measured using magnetic detection equipment including a permanent magnet magnetic measuring instrument, a permanent magnet pulse measuring instrument, and a vibrating sample magnetometer. Then, the data processing unit calculates K for point-by-point correction and outputs the true demagnetization curve and various magnetic performance indicators. The entire process requires only one sample and one measurement. From sample installation to final result output, it can be completed within minutes, significantly shortening the testing cycle and achieving the technical goal of rapidly obtaining the true magnetic properties of radially oriented permanent magnet rings.

[0063] Compared with existing technologies, this invention corrects the measurement results of radial ring samples through mathematical integral correction, systematically eliminating the measurement underestimation error caused by radial orientation, and obtaining true B values ​​suitable for engineering and quality control. 真实 -H i Curve. Using the method of this invention, the remanent magnetization of a radially oriented permanent magnet ring can be accurately calculated from the measured magnetic data of the sample. Magnetic performance indicators such as coercivity and maximum energy product are obtained, providing a reliable basis for the standardization of radially oriented permanent magnet rings and significantly improving the accuracy and consistency of magnetic performance evaluation. Simultaneously, it enhances the standardization and repeatability of radially oriented permanent magnet ring testing. First, a sample of a specified shape (cylindrical or cuboid) is taken radially from the radially oriented permanent magnet ring to be tested, and the geometric dimensions of the sample and its positional parameters on the tested radially oriented permanent magnet ring are accurately recorded. Second, correction coefficients are determined based on integral relationships. Finally, based on the initial demagnetization curve, M was applied point by point. 真实 H i =M 测量 H i / K performs reverse compensation to accurately restore the true demagnetization curve and magnetic performance parameters of the radially oriented permanent magnet ring.

[0064] The following is a further explanation with reference to specific embodiments: Terminology and coordinate system (to be clarified before calculating the K value) Origin O: Center of the radially oriented permanent magnet ring; the radial direction (magnetic orientation) is the y-axis, the tangential direction of the radially oriented permanent magnet ring is the x-axis, and the normal direction (central axis of the radially oriented permanent magnet ring) is the z-axis; the measurement axis is consistent with the radial y-axis.

[0065] Sample type and geometric parameters: Cylinder: Diameter D, Height H, Volume = ( / 2) 2 The rotational symmetry axis of the cylindrical sample must be along the magnetic orientation direction (radial direction) and be perpendicular to and coplanar with the central axis of the radially oriented permanent magnet ring.

[0066] Cuboid: radial width W, tangential length L, normal thickness T, volume V=LWT. One of the rotational symmetry axes of the cuboid sample must be along the magnetic orientation direction (radial direction) and be perpendicular to and coplanar with the central axis of the radially oriented permanent magnet ring.

[0067] Record the original sample data: Before all samples are tested, record D, H or L, W, T, the shortest distance h1 from the lower surface of the cylinder to the axis of the radially oriented permanent magnet ring to be tested, the normal thickness T along the radially oriented permanent magnet ring to be tested, and the shortest distance h2 from the lower surface of the cuboid to the axis of the radially oriented permanent magnet ring to be tested.

[0068] Step 1: Sample preparation and recording 1. Select one or more sampling positions along the radial direction on the radially oriented permanent magnet ring to be tested and cut out cylindrical or cuboid test samples. Grind the end faces of the samples to ensure that the end faces are flat and perpendicular.

[0069] 2. Sample processing methods can include wire cutting, grinding, and machining that does not alter the magnetic properties of the material.

[0070] 3. Record the sample's geometric and positional parameters and input them into the data processing unit.

[0071] Step 2: Demagnetization curve measurement 1. Mount the sample into the clamping position of the magnetic detection device (ensure the center of the sample is located in the magnetic circuit or the center of the measuring coil, and ensure axial alignment); 2. The magnetic field generating unit gradually applies the external field H according to the set magnetization-demagnetization program. i (i=1,2,...,N), in each H i The magnetization intensity M (Hi) of the sample was acquired using the selected measurement method, and the corresponding H was recorded. i The discrete data sequence obtained from the initial measurement is regarded as the initial demagnetization curve.

[0072] Step 3: Calculation of correction coefficient K 1. If the material has a macroscopically uniform response (i.e., the local M at the sample scale is independent of position), then the correction coefficient K is independent of the applied field H, and the correction coefficient K can be defined using a volume integral:

[0073] Where V is the volume of the test sample. ( , ) is the angle between a point at any position (x, y) on the sample and the radial direction of the radially oriented permanent magnet ring to be tested and the normal direction of the radially oriented permanent magnet ring.

[0074] 2. Perform exemplary integration on the cuboid sample. For the interval x∈[ in the x (tangential) and y (radial) planes For the projection of a cuboid into [W / 2, W / 2] and y∈[h, h+L], assuming that M is independent of position within this domain, the total projected magnetic moment of the sample in the y direction, obtained by the double integral along x and y, is:

[0075] The corresponding sample average projected magnetization M (measured) is M 测量 H i = =M

[0076] This yields the commonly used correction coefficient relationship. K=M 测量 / M=K=

[0077] and then M=M 测量 H i / K Step 4: Point-by-point correction of the demagnetization curve and output of results 1. For each sampling point H i The correction coefficient K obtained in step 3 is used to correct the measured values ​​according to the point-by-point relationship, resulting in M ​​corresponding to each sampling point. 真实 H i According to the fundamental magnetic relations B under the International System of Units (SI) 真实 H i =μ0H i +M 真实 H i Ultimately, it was obtained by M 真实 H i -H and B 真实 H i The key magnetic properties are extracted by the continuous curve formed by -H.

[0078] Example 1: The radially oriented permanent magnet ring magnetic performance detection device used in this embodiment includes: The sample clamping mechanism is used to fix the sample to be tested and ensure that at least one axis of the sample to be tested is aligned with the direction of the magnetic field applied during the test. A magnetic field generating unit is used to provide an external magnetic field; Magnetic measurement unit, used for applying an external magnetic field strength H i The magnetic response of the sample under test is measured and the measurement data, magnetization M, is output. 测量 ; The control and acquisition unit is used to control the magnetic field generating unit to operate according to a predetermined magnetic field sequence and to synchronously sample the magnetic measurement unit to obtain a complete initial demagnetization curve and obtain the magnetization intensity M. 测量 and the corresponding H i value; The data processing and automatic calibration unit is used to calculate the correction coefficient K based on the geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring under test, and to calculate the true magnetization M based on the correction coefficient K. 真实 After obtaining the correction M 真实 -H i The curve uses the actual magnetization M 真实 and the applied magnetic field strength H i The correspondence is obtained to obtain the true B. 真实 -H i curve; The results display unit is used to initially measure the demagnetization curve and the corrected M.真实 -H i The curve is displayed, and the magnetic property parameters before and after correction are shown simultaneously. It also includes an interface for inputting sample information, as well as a method for saving the initial demagnetization curve, correction function, and corrected M. 真实 -H i The storage unit for the curve.

[0079] This embodiment uses a sintered NdFeB radially oriented permanent magnet ring with an outer diameter of 20.0 mm, an inner diameter of 16.0 mm, and an axial height of 5.0 mm as the test object. The method and device described in this invention are used to illustrate in detail the magnetic performance detection and correction process.

[0080] Step 1: Sample preparation (sampling) Sampling location determination: Select a location in the radial direction of the radially oriented permanent magnet ring to be tested, and use a wire EDM machine to cut a rectangular test sample radially. Figure 2 As shown.

[0081] Sample processing: The cut samples are precision ground to ensure that all surfaces are flat and adjacent surfaces are perpendicular. The final sample geometry is: radial width W = 3.00 mm, tangential length L = 4.00 mm, and normal thickness T = 3.00 mm.

[0082] Geometric parameter recording: Establish a coordinate system with the center of the radially oriented permanent magnet ring as the origin (radial direction as Y-axis, tangential direction as X-axis, and normal direction as Z-axis). Measure and record the shortest distance h2 = 8.00 mm between the lower surface of the cuboid and the axis of the radially oriented permanent magnet ring under test. Input the sample geometric parameters (L, W, T, h2) into the data processing and automatic calibration unit of the detection device.

[0083] Step 2: Sample clamping The prepared cuboid sample is mounted onto the sample clamping mechanism of the detection device. By precisely adjusting the clamp, ensure that the radial direction of the sample (Y-axis, i.e., the length L direction) is strictly aligned with the direction of the subsequently applied magnetic field. The geometric center of the sample is located in the central region of the measuring coil or magnetic circuit. The sample is securely fixed, with no displacement or vibration during the measurement process.

[0084] Step 3: Initial measurement of the demagnetization curve (measurement) Equipment selection: A permanent magnet magnetic measuring instrument was selected, and its measuring coil meets the requirements of Chinese national standard GB / T 3217-2013.

[0085] Magnetic field sequence setting: The control and acquisition unit issues commands to cause the magnetic field generating unit to execute the following magnetization-demagnetization procedure: Positive saturation magnetization: Apply a magnetic field Hsat = 3000 kA / m (ensure it is greater than the intrinsic coercivity of the material).

[0086] Demagnetization scan: Gradually reduce the magnetic field from +3000 kA / m to 1500 kA / m, with the step size dynamically adjusted according to the curve's rate of change.

[0087] Data acquisition: at each magnetic field setpoint H i After stabilization (stabilization time > 50 ms), the control and acquisition units synchronously trigger the magnetic measurement unit to acquire the corresponding magnetic polarization intensity M. 测量 H i (For BH meters, M and B are usually measured directly. In this embodiment, M is measured.) 测量 H i Record the complete set of initial demagnetization data points (H). i M 测量 H i To simplify the description, this embodiment extracts some key data points as follows (complete data is used for subsequent calculations):

[0088] Step 4: Data Processing and Calculation of Correction Coefficient K (Data Processing) Calibration Model Selection: Since this embodiment uses a cuboid sample, the data processing and automatic calibration unit automatically calls the pre-stored cuboid analytical integral formula to calculate the correction coefficient K. According to the present invention, K is defined as the volume average of the cosine of the angle between the radial direction and the measurement axis (y-axis) at each point within the sample volume.

[0089] For a cuboid sample, the integral over the thickness T in the normal direction (z direction) is independent of x and y, and therefore can be simplified to an area average: K=

[0090] in: L = 4.00 mm: Radial length of the sample (along the y-axis); W=3.00 mm: Sample tangential width (along the x-axis); h2 = 8.00 mm: Distance from the lower surface of the sample to the center of the radially oriented permanent magnet ring (y-axis starting coordinate). Substituting the geometric parameters to calculate K: Substituting L=0.004 m, W=0.003 m, and h2=0.008 m into the above double integral formula, and obtaining the result through numerical integration: K≈0.847 Step 5: Correct point by point to obtain the true demagnetization curve (data output) Point-by-point correction: The data processing unit corrects each magnetic field point H measured in step 3.i Applying the formula M to the actual H i = M 测量 H i / K was corrected. The corrected key data is as follows:

[0091] Export complete performance parameters: Intrinsic magnetic properties: from the modified M 真实 Extracted from the Hi-H curve. True remanence B. r =M 真实 (0) = 1.003T Innate coercivity H cj =950 kA / m (corresponding to M) 真实 H i (Magnetic field dropping to zero).

[0092] According to B 真实 =μ0H+M 真实 Calculate B 真实 And extract the magnetic coercivity H cb ≈ 980 kA / m and maximum energy product (BH) max ≈198 kJ / m 3 .

[0093] Step 6: Result Verification To verify the accuracy of the method of this invention, a comparative verification was performed using the traditional multi-diameter sample column extrapolation method: A series of cuboid samples with different tangential widths W (i.e. different cross-sectional areas) were machined from the same radial position of the same radially oriented permanent magnet ring. The tangential widths W were 1.0 mm, 2.0 mm, 3.0 mm and 4.0 mm, respectively.

[0094] The apparent remanence B of these samples was measured respectively. r,meas .

[0095] B r,meas Plotting W and performing linear fitting, extrapolating to W=0 (i.e., the ideal single grain width), yields the extrapolated remanence value B. r,extrap =1.01T.

[0096] Comparison results: The residual magnetism B obtained by the method of this invention in a single measurement correction r,true =1.003T, the deviation from the extrapolation result of 1.01 T is only 0.7%, far smaller than the deviation between the uncorrected initial measurement of 0.85T and the true value (approximately 16%). Meanwhile, the intrinsic coercivity H... cj The measured value (950 kA / m) is in high agreement with the extrapolation result (956 kA / m).

[0097] Step 7: Result Display and Storage Display: The results display unit synchronously displays the demagnetization curves before and after correction (M 真实 -H i and B 真实 - H i The table comparing key performance parameters clearly shows that all indicators have been significantly improved after correction and are close to the extrapolated true values.

[0098] Storage: After the operator enters the batch number, sample number, and other information of the radially oriented permanent magnet ring through the sample information input interface, the storage unit automatically stores the original measurement data (H... i M 测量 H i ), correction coefficient (K=0.847), and corrected true curve data (H) i M 真实 H i The final performance parameters are saved to the database for subsequent quality traceability and statistical analysis.

[0099] Example 2 The parameters of the sample cylinder, the apparatus used, and the testing methods are the same as in Example 1.

[0100] The difference lies in the following: the geometric parameters of the cylinder in step 1, including the diameter D, height H, and the shortest distance h1 from the lower surface of the cylinder to the axis of the radially oriented permanent magnet ring to be measured, are: diameter D = 3mm, height H = 4mm, h1 = 8mm.

[0101] The extracted key data from step 3 is as follows (the complete data is used for subsequent calculations):

[0102] Step 4: Since this embodiment uses a cylindrical sample, the data processing and automatic calibration unit automatically calls the pre-stored cylindrical volume integral model to calculate the correction coefficient K. According to the present invention, K is defined as the volume average of the cosine of the angle between the radial magnetic orientation direction at each point within the sample volume and the measurement axis (Y-axis):

[0103] For a cylindrical sample, its central axis is along the Y-axis (radial), and its cross-section is a circle in the XZ plane; and cosθ depends only on the X and Y coordinates, and is independent of the Z coordinate, therefore the volume integral can be simplified to: K=

[0104] The cylinder diameter D = 3.0 mm; the cylinder height H in the radial direction H = 4.0 mm; and the distance h1 from the lower end face of the cylinder to the center of the radially oriented permanent magnet ring = 8.0 mm.

[0105] Substituting the geometric parameters to calculate K: Substituting D=0.003 m, H=0.004 m, h1=0.008 m into the above double integral formula, and obtaining it through numerical integration: K≈0.872 The corrected key data from step 5 is as follows:

[0106] Export complete performance parameters: Intrinsic magnetic properties: from the modified M 真实 H i Extracted from the -H curve. True remanence B r =M 真实 (0) = 1.003T Innate coercivity H cj =950 kA / m (corresponding to M) 真实 H i (Magnetic field dropping to zero).

[0107] According to B 真实 =μ0H+M 真实 Calculate B 真实 And extract the magnetic coercivity H cb ≈ 980 kA / m and maximum energy product (BH) max ≈198 kJ / m 3 .

[0108] Step 6: Result Verification To verify the accuracy of the method of this invention, a comparative verification was performed using the traditional multi-diameter sample column extrapolation method: A series of cylindrical samples with different diameters were machined from the same radial position of the same radially oriented permanent magnet ring. The diameters D were 1.0 mm, 2.0 mm, 3.0 mm and 4.0 mm, respectively, and the height was kept at 4.0 mm.

[0109] The apparent remanence B of these samples was measured respectively. r,meas .

[0110] B r,meas Plotting D and performing linear fitting, extrapolating to D=0 (i.e., the limit of zero size and completely consistent orientation), yields the extrapolated remanence value B. r,extrap =1.01T.

[0111] Comparison results: The residual magnetism B obtained by the method of this invention in a single measurement correction r,true =1.003T, the deviation from the extrapolation result of 1.01 T is only 0.7%, far smaller than the deviation between the uncorrected initial measurement of 0.875T and the true value (approximately 13.4%). Meanwhile, the intrinsic coercivity H...cj The measured value (950 kA / m) is in high agreement with the extrapolation result (956 kA / m).

[0112] Step 7: Result Display and Storage Display: The results display unit synchronously displays the demagnetization curves before and after correction (M 真实 -H i and B 真实 - H i The table comparing key performance parameters clearly shows that all indicators have been significantly improved after correction and are close to the extrapolated true values.

[0113] Storage: After the operator enters the batch number, sample number, and other information of the radially oriented permanent magnet ring through the sample information input interface, the storage unit automatically stores the original measurement data (H... i M 测量 H i ), correction coefficient (K=0.872), and corrected true curve data (H) i M 真实 H i The final performance parameters are saved to the database for subsequent quality traceability and statistical analysis.

[0114] The technical solutions of this invention are not limited to the specific embodiments described above. Any technical modifications, alterations, substitutions, and variations made to the technical solutions of this invention without departing from the spirit and scope of the claims are within the protection scope of this invention.

Claims

1. A method for detecting the magnetic properties of a radially oriented permanent magnet ring, characterized in that, Includes the following steps: S1: Sample from the radially oriented permanent magnet ring to be tested using a radial method, and record the geometric dimensions of the sample and its position parameters on the radially oriented permanent magnet ring to be tested; S2: Calculate the correction coefficient K based on the sample's geometric dimensions and positional parameters; S3: Initial demagnetization curve of the test sample; S4: Based on the initial demagnetization curve, obtain the magnetization intensity M. 测量 The true magnetization M is calculated based on the correction factor K. 真实 M 真实 = M 测量 / K, after correction, M 真实 -H i curve; S5: Utilizing the actual magnetization M 真实 and the applied magnetic field strength H i Based on the correspondence, the magnetic induction intensity B of the sample is calculated. 真实 To obtain the true B 真实 -H i curve.

2. The method for detecting the magnetic properties of a radially oriented permanent magnet ring according to claim 1, characterized in that, In S1, the sample is a cylinder or a cuboid. The axis of the cylinder is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the normal direction of the radially oriented permanent magnet ring to be tested is the same as the magnetic orientation direction of the radially oriented permanent magnet ring to be tested. The axis of the cuboid parallel to the tangent direction of the radially oriented permanent magnet ring to be tested is parallel to the axis of the radially oriented permanent magnet ring to be tested.

3. The method for detecting the magnetic properties of a radially oriented permanent magnet ring according to claim 2, characterized in that, The geometric dimensions of the cylinder include diameter D, height H, and the shortest distance h1 from the lower surface of the cylinder to the axis of the radially oriented permanent magnet ring to be tested. The geometric dimensions of the cuboid include the tangential length L along the radial orientation permanent magnet ring to be tested, the radial width W along the radial orientation permanent magnet ring to be tested, the normal thickness T along the radial orientation permanent magnet ring to be tested, and the shortest distance h2 from the lower surface of the cuboid to the axis of the radial orientation permanent magnet ring to be tested. And / or, the position parameters include establishing a coordinate system with the geometric center of the radially oriented permanent magnet ring to be tested as the origin, wherein the radial direction of the radially oriented permanent magnet ring is the y-axis, the tangential direction is the x-axis, and the normal direction is the z-axis.

4. A method for detecting the magnetic properties of a radially oriented permanent magnet ring according to any one of claims 1-3, characterized in that, In S2, the correction coefficient K is determined by the following integral relationship: ； Where V is the volume of the sample. ( , ) is the angle between a point at any position (x, y) on the sample and the radial direction of the radially oriented permanent magnet ring to be tested and the normal direction of the radially oriented permanent magnet ring.

5. A method for detecting the magnetic properties of a radially oriented permanent magnet ring according to any one of claims 1-3, characterized in that, In S3, the initial demagnetization curve is measured by one of the following: a permanent magnet magnetic measuring instrument, a permanent magnet pulse measuring instrument, or a vibrating sample magnetometer.

6. A method for detecting the magnetic properties of a radially oriented permanent magnet ring according to any one of claims 1-3, characterized in that, In S4, according to the corrected M 真实 -H i The curve yields the remanent magnetization. Innate self-control Knee point magnetic field .

7. A method for detecting the magnetic properties of a radially oriented permanent magnet ring according to any one of claims 1-3, characterized in that, In S5, based on the real B 真实 -H i The curve yields the coercivity H. cB and maximum magnetic energy product BH max .

8. A method for detecting the magnetic properties of a radially oriented permanent magnet ring according to any one of claims 1-3, characterized in that, Sampling in S1 includes wire cutting or grinding.

9. A radially oriented permanent magnet ring magnetic property detection device for use in the method described in any one of claims 1-3, characterized in that, include: The sample clamping mechanism is used to fix the sample to be tested and ensure that at least one axis of the sample to be tested is aligned with the direction of the magnetic field applied during the test. A magnetic field generating unit is used to provide an external magnetic field; Magnetic measurement unit, used for applying an external magnetic field strength H i The magnetic response of the sample under test is measured and the measurement data, magnetization M, is output. 测量 ; The control and acquisition unit is used to control the magnetic field generating unit to operate according to a predetermined magnetic field sequence and to synchronously sample the magnetic measurement unit to obtain a complete initial demagnetization curve and obtain the magnetization intensity M. 测量 and the corresponding H i value; The data processing and automatic calibration unit is used to calculate the correction coefficient K based on the sample's geometric dimensions and position parameters on the radially oriented permanent magnet ring under test, and to calculate the true magnetization M based on the correction coefficient K. 真实 After obtaining the correction M 真实 -H i The curve uses the actual magnetization M 真实 and the applied magnetic field strength H i The correspondence is obtained to obtain the true B. 真实 -H i curve; The results display unit is used to initially measure the demagnetization curve and the corrected M. 真实 -H i The curve is displayed, and the magnetic property parameters before and after correction are shown simultaneously.

10. The detection device according to claim 9, characterized in that, It also includes tools for saving the initial demagnetization curve, correction function, and corrected M. 真实 -H i The storage unit for the curve.

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