Magnetization Measurement Device and Method for Irregularly Shaped Permanent Magnets in Motor Applications

Abstract

This invention discloses a device and method for measuring the magnetization intensity of irregularly shaped permanent magnets in motor applications. The bottom of the measuring device is configured as a workbench, on which an L-shaped placement platform is inclinedly arranged. A lifting component is slidably connected to the inner side of the long side of the L-shaped placement platform. A magnetically conductive clamping iron core is clamped onto the lifting component, and a measuring coil is wound on the magnetically conductive clamping iron core. The magnetically conductive clamping iron core also has a clamping gap for the irregularly shaped permanent magnet, and the clamping gap for the irregularly shaped permanent magnet is arranged opposite to the measuring coil. During measurement, the irregularly shaped permanent magnet can be clamped by the magnetically conductive clamping iron core, and then the lifting component drives the magnetically conductive clamping iron core to slide on the long side of the L-shaped placement platform, thereby achieving rapid positioning and directional cutting of the magnetic circuit, and thus accurately measuring the magnetic flux of the iron core. The magnetization intensity of the permanent magnet can be calculated, and this magnetization intensity can be used for magnetic circuit calculation of permanent magnets in motor applications, thereby achieving accurate measurement of the magnetization intensity of irregularly shaped permanent magnets.

Description

Technical Field

[0001] This invention relates to the fields of permanent magnet applications and permanent magnet motor technology, and particularly to a magnetization intensity measuring device and method for irregularly shaped permanent magnets in motor applications. Background Technology

[0002] Permanent magnet motors have been widely used worldwide due to their simple structure and high power density and torque density. In order to further improve the performance of permanent magnet motors, industry experts and scholars have conducted extensive research on their topology, resulting in the emergence of various new structures. The application of permanent magnet materials has also become more unique and extensive.

[0003] Based on the location of the permanent magnets, permanent magnet motors can be broadly classified into two types: built-in and surface-mounted. Based on the magnetization method of the permanent magnets, they can be broadly classified into two types: radial magnetization and parallel magnetization. In recent years, many scholars have also conducted relevant research on Halbach magnetization. It can be seen that as the main magnetic source in permanent magnet motors, the magnetization effect of permanent magnets will directly affect key tasks such as magnetic circuit calculation and motor design.

[0004] Currently, the evaluation of permanent magnet magnetization effectiveness largely focuses on the material itself, specifying key indicators such as remanence, coercivity, and energy product. However, once the permanent magnet is magnetized by the manufacturer, the actual magnetization direction and effect are impossible for motor designers and researchers to assess. The industry currently uses two common measurement methods: gaussmeters and fluxmeters. The former measures the magnetic field strength at a specific point using a Hall element, while the latter measures the magnetic flux generated by the permanent magnet within the coil. These two methods clearly cannot fully demonstrate the actual magnetization effect of the permanent magnet, and therefore cannot indicate the contribution of the permanent magnet as a magnetic source to the magnetic circuit in a permanent magnet motor. This problem exists even for geometrically regular permanent magnets; for geometrically irregular permanent magnets, such as the conical permanent magnets used in conical motors or the spherical permanent magnets used in spherical motors, the actual magnetization effect will result in even greater calculation errors. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a magnetization intensity measuring device and method for irregularly shaped permanent magnets in motor applications. This invention aims to solve the problem that existing measuring devices, when directly measuring the magnetization effect of irregularly shaped permanent magnets using gaussmeters and fluxmeters, do not consider the influence of the permanent magnet shape on the magnetic flux, resulting in large deviations in the magnetization effect detection results.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In the first aspect, a magnetization intensity measuring device for an irregularly shaped permanent magnet in an electric motor application is provided. The bottom of the measuring device is set as a workbench, and an L-shaped placement platform is arranged at an incline on the workbench. A lifting component is slidably connected to the inner side of the long side of the L-shaped placement platform. A magnetic clamping iron core is clamped on the lifting component. A measuring coil is wound on the magnetic clamping iron core. An irregularly shaped permanent magnet clamping gap is also opened on the magnetic clamping iron core, and the irregularly shaped permanent magnet clamping gap is arranged opposite to the measuring coil.

[0007] Furthermore, the magnetic clamp core includes an upper end and a lower end. The upper end of the clamp core has a square column structure, and the lower end has a U-shaped structure. The upper end of the clamp core is located at the open end of the lower end of the clamp core. The measuring coil is wound in the middle of the lower end of the clamp core, and an irregular permanent magnet clamping gap is opened at the upper end of the clamp core.

[0008] Furthermore, the clamping gap of the irregular permanent magnet is conical or spherical.

[0009] Furthermore, the inner side of the long side of the L-shaped placement platform is provided with a guide groove and a positioning groove, and the end of the long side of the L-shaped placement platform is provided with a pull wire hole. The lifting component is locked in the guide groove, and a pull wire is also connected to the lifting component. The pull wire is inserted through the pull wire hole. The positioning groove is opened at the end of the long side of the L-shaped placement platform.

[0010] Furthermore, the lifting component includes a guide plate and a clamping pin. The surface area of ​​the guide plate is smaller than the surface area of ​​the positioning groove. The guide plate is provided with a guide key, which cooperates with the guide groove. The guide plate is also provided with multiple interlocking holes, and the clamping pin is inserted into the interlocking holes.

[0011] Furthermore, an elastic washer is fitted onto the clamping pin.

[0012] Furthermore, the inclination angle between the short side of the L-shaped placement platform and the workbench plane is 10°-20°. The L-shaped placement platform enables the iron core clamp to adhere tightly to the surface of the lifting component by its own weight. During the lifting process, it can ensure that the upper and lower ends of the clamp iron core remain vertically separated. In addition, the long side of the L-shaped placement platform is also equipped with reinforcing ribs.

[0013] Furthermore, the two ends of the measuring coil are connected to terminals via twisted wires, and the terminals are located on the workbench. Secondly, a method for measuring magnetization intensity using a non-circular permanent magnet in motor applications, the method comprising: Step 1: Clamp the permanent magnet to be tested in the clamping gap of the irregular permanent magnet, center it with the upper end of the iron core of the magnetic clamp and clamp it tightly, and bind it firmly with binding straps in the horizontal direction. Step 2: Select a suitable insertion hole on the lifting plate according to the size of the magnetic clamp core, insert the clamping pin and elastic washer, clamp the upper end of the horizontally fixed magnetic clamp core with the elastic washer, and place it in the middle position of the lifting plate. Step 3: Place the lower end of the clamp core with the test coil wound on the placement plane of the workbench, and lead the wiring out to the workbench terminal. Step 4: Adjust the lifting components to ensure that the upper end of the clamp core is precisely stacked on the lower end of the clamp core, ensuring that there are no gaps at the end faces; Step 5: Lead the cable of the lifting component out through the cable hole of the workbench and place it on the back of the workbench; Step 6: Connect the fluxmeter to the terminal block and turn on the instrument to prepare for measurement; Step 7: Quickly pull the line along the horizontal direction to make the lifting component quickly rise along the worktable guide groove to the positioning groove position and fall into the groove and lock. Step 8: Record the fluxmeter reading. Based on the theory of magnetomotive force and magnetic permeability, the actual magnetization intensity of the permanent magnet is obtained through conversion. The measurement is then completed.

[0014] The technical solution adopted in this invention has the following beneficial effects: 1. A closed magnetic circuit is constructed using a magnetically conductive clamp core. The working point of the permanent magnet in the measurement scenario is close to that of the actual application scenario, and the magnetic circuit continuity is controllable. Utilizing the structural characteristics of the worktable tilt angle and lifting components, the magnetically conductive clamp core is clamped by clamping pins, so that the end face of the core completely covers the surface of the permanent magnet being measured, minimizing air gap magnetic resistance and accurately measuring the magnetic flux generated by the magnetization intensity of the permanent magnet. In principle, any permanent magnet with uniform thickness can be measured using this method, including but not limited to conical and spherical shapes. 2. The magnetic clamp core has a flexible structure, allowing for the measurement of various irregularly shaped permanent magnets by changing the upper clamp. The upper end of the clamp core is a square column structure, while the lower end is a U-shaped structure. This combination of square column and U-shaped structures ensures that the cross-sectional size of the magnetic clamp core is larger than that of the permanent magnet, and the difference in size in any direction is greater than the thickness of the permanent magnet. This takes into account the actual working conditions of the permanent magnet in the motor's magnetic circuit, reducing its leakage flux. The magnetic clamp core material has isotropic high magnetic permeability and is less prone to saturation than permanent magnets. Consequently, most of the magnetic voltage drop in the magnetic circuit is concentrated at the permanent magnet, and the core reluctance is negligible. Core materials include, but are not limited to, pure iron and silicon steel. 3. Except for the flux meter, clamp core, measuring coil, and terminals, all other components of the measuring device are made of insulating and poorly magnetic materials, including but not limited to polymethyl methacrylate (acrylic), epoxy resin, high-density laminated wood, and high-density laminated cardboard; the measuring coil leads out to the terminals using twisted wire; the materials and structural measures minimize measurement errors caused by external induced magnetic fields. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the magnetization intensity measuring device for the irregularly shaped permanent magnet described in this invention. Figure 2 This is a schematic diagram of the measurable permanent magnets of different shapes described in this invention; Figure 3 This is a schematic diagram of the segmented magnetic core and measuring coil structure described in this invention; Figure 4 This is a schematic diagram of the lifting component structure described in this invention.

[0016] The components include: 1. Terminal block; 2. Placement platform; 3. Lower end of clamp core; 4. Upper end of clamp core; 5. Pull wire hole; 6. Pull wire; 7. Positioning groove; 8. Guide groove; 9. Elastic washer; 10. Clamping pin; 11. Lifting assembly; 12. Measuring coil; 13. Workbench; 14. Lifting plate; 15. Guide key; 16. Insertion hole; and 17. Clamping gap for irregularly shaped permanent magnets. Detailed Implementation

[0017] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0018] This invention relates to a magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications, combined with... Figure 1 The bottom of the measuring device is set as a workbench 13. An L-shaped placement platform 2 is arranged at an angle on the workbench 13. A lifting component 11 is slidably connected to the inner side of the long side of the L-shaped placement platform 2. A magnetic clamp core is snapped onto the lifting component 11. A measuring coil 12 is wound on the magnetic clamp core. An irregular permanent magnet clamping gap 17 is also opened on the magnetic clamp core, and the irregular permanent magnet clamping gap 17 is arranged opposite to the measuring coil 12.

[0019] During measurement, the irregularly shaped permanent magnet can be clamped by the magnetic clamp core, and then the lifting component 11 drives the magnetic clamp core to slide on the long side of the L-shaped placement platform 2 to achieve rapid positioning and directional cutting of the magnetic circuit, simulating the magnetic circuit effect of the permanent magnet in actual work, realizing the measurement of the irregularly shaped permanent magnet, and reducing the deviation in the detection of the magnetization effect of the permanent magnet.

[0020] In this embodiment, combined with Figure 1 and Figure 3The magnetic clamp core includes an upper clamp core 4 and a lower clamp core 3. The upper clamp core 4 is a square column structure, and the lower clamp core 3 is a U-shaped structure. The upper clamp core 4 is located at the open end of the lower clamp core 3. The measuring coil 12 is wound in the middle of the lower clamp core 3. The upper clamp core 4 has an irregular permanent magnet clamping gap 17.

[0021] In this embodiment, the clamp core of the magnetic circuit is designed in segments. The shape of the contact surface with the permanent magnet is designed to be completely consistent with the shape of the permanent magnet. Its cross-sectional size is larger than that of the permanent magnet, and the difference in size in any direction is greater than the thickness of the permanent magnet, so as to simulate the working magnetic circuit state of the permanent magnet in the motor. The upper end 4 of the clamp core can be adapted and replaced according to the shape of the permanent magnet being measured. The lower end 3 of the clamp core is tightly wound with the measuring coil 12 on the core to measure the magnetic flux.

[0022] The magnetic clamp core has a flexible structure, allowing for the measurement of various irregularly shaped permanent magnets by changing its upper clamp. The upper end 4 of the clamp core is a square column structure, while the lower end 3 is a U-shaped structure. This combination of square column and U-shaped structures ensures that the cross-sectional size of the magnetic clamp core is larger than that of the permanent magnet, and the difference in size in any direction is greater than the thickness of the permanent magnet. This takes into account the actual working conditions of the permanent magnet in the motor's magnetic circuit, reducing its leakage flux. The core material has isotropic high magnetic permeability and is less prone to saturation than permanent magnets. Consequently, most of the magnetic voltage drop in the magnetic circuit is concentrated at the permanent magnet, and the core reluctance is negligible. Core materials include, but are not limited to, pure iron and silicon steel.

[0023] In this embodiment, the clamping gap 17 for the irregularly shaped permanent magnet is conical or spherical. This gap shape allows for the detection of the magnetization effect of conical or spherical permanent magnets. In principle, any permanent magnet of uniform thickness can be measured using this method, including but not limited to... Figure 2 The examples are conical and spherical.

[0024] In this embodiment, combined with Figure 1 The L-shaped placement platform 2 has a guide groove 8 and a positioning groove 7 on the inner side of its long side. The end of the long side of the L-shaped placement platform 2 has a pull wire hole 5. The lifting component 11 is inserted into the guide groove 8 and a pull wire 6 is connected to the lifting component 11. The pull wire 6 is inserted through the pull wire hole 5. The positioning groove 7 is opened at the end of the long side of the L-shaped placement platform 2.

[0025] The L-shaped placement platform 2 of the clamp core is perpendicular to the lifting direction of the lifting assembly 11; its guide groove 8 provides a guiding function for the lifting assembly 11; its positioning groove 7 provides a positioning and locking function for the lifting assembly 11; and its pull wire hole 5 provides a positioning and guiding function for the pull wire 6.

[0026] By pulling the lifting component 11 along the guide groove 8 using the pull wire 6, the magnetic circuit can be quickly cut off. At the same time, after the lifting component 11 is pulled up, it can be locked in the positioning groove 7 to avoid deviation in magnetic flux measurement caused by the component falling back.

[0027] In this embodiment, combined with Figure 1 and Figure 4 The lifting component 11 includes a guide plate and a clamping pin 10. The surface area of ​​the guide plate is smaller than the surface area of ​​the positioning groove 7. The guide plate is provided with a guide key 15, which cooperates with the guide groove 8. The guide plate is provided with multiple insertion holes 16 arranged at intervals. The clamping pin 10 is inserted into the insertion hole 16, and an elastic washer 9 is sleeved on the clamping pin 10.

[0028] The lifting plate 14 has insertion holes 16 distributed at different positions. The clamping pin 10 and the elastic washer 9 have multiple sizes of accessories. By matching the sizes of the insertion holes 16, clamping pin 10 and elastic washer 9, the irregular jig core can be clamped in multiple directions, so that the irregular jig core can clamp the irregular permanent magnet, reduce the influence of the working gap on the magnetic flux measurement, and facilitate the clamping of irregular jig cores of multiple sizes. Since the worktable 13 has an inclined platform, the lifting component 11 is constrained by its own weight and the guide groove 8 of the worktable 13. The lifting component 11 can be quickly lifted to the designated position and locked by the pull wire 6 through the pull wire hole 5.

[0029] In this embodiment, the inclination angle between the short side of the L-shaped placement platform 2 and the plane of the worktable 13 is 10°-20°. The L-shaped placement platform enables the iron core clamp to adhere tightly to the surface of the lifting component by its own weight, ensuring that the upper and lower ends of the clamp iron core remain vertically separated during the lifting process. Furthermore, the long side of the L-shaped placement platform 2 is also provided with reinforcing ribs.

[0030] In this embodiment, combined with Figure 1 The two ends of the measuring coil 12 are led out to the terminals 1 through twisted wires, and the terminals 1 are located on the workbench 13. The measuring coil 12 is tightly attached to the iron core of the clamp, and the coil leads are twisted under the workbench 13 and led out to the terminals 1 of the workbench 13. The terminals are connected to the magnetometer to achieve the state of minimal leakage flux in the measuring magnetic circuit, so that the measurement result is close to the true value.

[0031] In this invention, apart from the fluxmeter, the irregularly shaped clamp core, the measuring coil 12, and the terminal block 1, all other components of the measuring device are made of insulating and poorly magnetic materials. These materials include, but are not limited to, polymethyl methacrylate (acrylic), epoxy resin, high-density laminated wood, and high-density laminated cardboard. The measuring coil 12 is led out using twisted wire to the terminal block 1. The materials and structural measures minimize the measurement error caused by the external induced magnetic field.

[0032] Secondly, a method for measuring magnetization intensity using a non-circular permanent magnet in motor applications, the method comprising: Step 1: Clamp the permanent magnet to be tested in the clamping gap 17 of the irregular permanent magnet, clamp it tightly after centering the upper 4 parts of the iron core with the magnetic clamp, and tie it firmly in the horizontal direction with binding straps. Step 2: Select a suitable insertion hole 16 on the lifting plate 14 according to the size of the magnetic clamp core, insert the clamping pin 10 and elastic washer 9, clamp the upper 4 parts of the horizontally fixed magnetic clamp core with elastic washer 9, and place it in the middle position of the lifting plate 14. Step 3: Place the lower end 3 of the clamp core with the test coil wound on the placement plane of the workbench 13, and lead the wiring out to the terminal 1 of the workbench 13; Step 4: Adjust the lifting component 11 so that the upper end 4 of the clamp core is precisely stacked on the lower end 3 of the clamp core, ensuring that there is no gap at the end face; Step 5: Lead out the pull cable 6 of the lifting component 11 through the pull cable hole 5 of the worktable 13 and place it on the back of the worktable 13. Step 6: Connect the fluxmeter to terminal 1 and turn on the instrument to prepare for measurement; Step 7: Quickly pull the line 6 along the horizontal direction so that the lifting component 11 is quickly lifted along the guide groove 8 of the worktable 13 to the position of the positioning groove 7 and falls into the groove and locks in place; Step 8: Record the fluxmeter reading. Based on the theory of magnetomotive force and magnetic permeability, the actual magnetization intensity of the permanent magnet is obtained through conversion. The measurement is then completed.

[0033] During measurement, the measured value is the magnetic flux of the core cross-section of the magnetic clamp. The value is based on the formula. The magnetic flux density inside the iron core can be calculated. ,in Let be the cross-sectional area of ​​the iron core wrapped around the coil being tested, based on the fundamental constitutive relation of the magnetic field. ,in, The permeability of free space, The relative permeability of the core material, The magnetic field strength, The magnetization intensity of the permanent magnet can be considered as follows: since the constructed magnetic circuit is not excited by a current source, it can be assumed that... If the permanent magnet in the magnetic circuit is the only magnetic source, then its magnetization can be calculated. .

[0034] In this invention, a measuring device is used to vertically cut the magnetic circuit in a short time. The physical magnetic circuit is constructed in conjunction with the measuring coil 12 to avoid magnetic leakage. The measured magnetic flux is regarded as the total magnetic flux generated by the permanent magnet in the magnetic circuit. Then, the magnetization intensity of the permanent magnet is accurately calculated, and the magnetization effect of the irregular permanent magnet is quantitatively measured.

Claims

1. A magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications, characterized in that, The bottom of the measuring device is set as a workbench (13), and an L-shaped placement platform (2) is arranged on the workbench (13) at an angle. A lifting component (11) is slidably connected to the inner side of the long side of the L-shaped placement platform (2). A magnetic clamp core is snapped onto the lifting component (11), and a measuring coil (12) is wound on the magnetic clamp core. A shaped permanent magnet clamping gap (17) is also opened on the magnetic clamp core, and the shaped permanent magnet clamping gap (17) is arranged opposite to the measuring coil (12).

2. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 1, characterized in that, The magnetic clamp core includes an upper end (4) and a lower end (3). The upper end (4) of the clamp core is a square column structure, and the lower end (3) of the clamp core is a U-shaped structure. The upper end (4) of the clamp core is located at the open end of the lower end (3) of the clamp core. The measuring coil (12) is wound in the middle of the lower end (3) of the clamp core. The upper end (4) of the clamp core has an irregular permanent magnet clamping gap (17).

3. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 1, characterized in that, The clamping gap (17) of the irregular permanent magnet is conical or spherical.

4. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 1, characterized in that, The L-shaped placement platform (2) has a guide groove (8) and a positioning groove (7) on the inner side of its long side. The end of the long side of the L-shaped placement platform (2) has a pull wire hole (5). The lifting component (11) is installed in the guide groove (8) and a pull wire (6) is connected to the lifting component (11). The pull wire (6) is inserted through the pull wire hole (5). The positioning groove (7) is located at the end of the long side of the L-shaped placement platform (2).

5. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 4, characterized in that, The lifting component (11) includes a guide plate and a clamping pin (10). The surface area of ​​the guide plate is smaller than the surface area of ​​the positioning groove (7). The guide plate is provided with a guide key (15), which cooperates with the guide groove (8). The guide plate is provided with multiple interlocking holes (16) arranged at intervals. The clamping pin (10) is inserted into the interlocking hole (16).

6. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 5, characterized in that, An elastic washer (9) is fitted on the clamping pin (10).

7. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 1, characterized in that, The angle between the short side of the L-shaped placement platform (2) and the plane of the workbench (13) is 10°-20°, and the long side of the L-shaped placement platform (2) is also provided with reinforcing ribs.

8. The magnetization intensity measuring device for irregularly shaped permanent magnets in motor applications according to claim 1, characterized in that, The two ends of the measuring coil (12) are led out with terminals (1) through twisted wires, and the terminals (1) are located on the workbench (13).

9. A method for measuring magnetization intensity using a device for measuring the magnetization intensity of an irregularly shaped permanent magnet in motor applications as described in any one of claims 1-8, characterized in that, Measurement methods include: Step 1: Clamp the permanent magnet to be tested in the clamping gap (17) of the irregular permanent magnet, clamp it tightly after centering the upper end (4) of the iron core of the magnetic clamp, and tie it firmly in the horizontal direction with the binding strap. Step 2: Select a suitable insertion hole (16) on the lifting plate (14) according to the size of the magnetic clamp core, insert the clamping pin (10) and elastic washer (9), clamp the upper end (4) of the horizontally fixed magnetic clamp core with elastic washer (9), and place it in the middle position of the lifting plate (14); Step 3: Place the lower end (3) of the clamp core with the test coil wound on the placement plane of the workbench (13), and lead the wiring out to the wiring terminal (1) of the workbench (13). Step 4: Adjust the lifting component (11) so that the upper end (4) of the clamp core is accurately placed on the lower end (3) of the clamp core to ensure that there is no gap at the end face; Step 5: Lead out the pull wire (6) of the lifting component (11) through the pull wire hole (5) of the worktable (13) and place it on the back of the worktable (13); Step 6: Connect the fluxmeter to terminal (1) and turn on the instrument to prepare for measurement; Step 7: Quickly pull the line (6) along the horizontal direction so that the lifting component (11) is quickly lifted along the guide groove (8) of the worktable (13) to the position of the positioning groove (7) and falls into the groove and locks. Step 8: Record the fluxmeter reading. Based on the theory of magnetomotive force and magnetic permeability, the actual magnetization intensity of the permanent magnet is obtained through conversion. The measurement is then completed.

Images