A metal hot deformation amount measuring device based on hall effect and a measuring method thereof

Abstract

The application discloses a metal thermal deformation quantity measuring device based on Hall effect, which comprises a metal wire expansion coefficient test experiment instrument into which a metal rod to be measured is placed, a Hall element and a Hall effect experiment instrument, the metal wire expansion coefficient test experiment instrument is placed longitudinally, the Hall element is placed horizontally and one end of the Hall element is connected with a metal striker of the metal wire expansion coefficient test experiment instrument through a connecting clamp, the other end of the Hall element is connected with a calibration part, and the Hall element is adjusted to a uniform variable magnetic field area after calibration experiment. The thermal deformation quantity of the metal rod is converted into displacement quantity of the Hall element in the uniform variable magnetic field through the connecting clamp, and the size of the corresponding part can be changed according to the size parameters and environmental influence of different metal rods, wherein the calibration experiment before the experiment starts can help to determine the area with the most significant Hall voltage change, the change of the Hall voltage is amplified by an operational amplifier, the accuracy of the result is ensured, the high-precision, low-cost and simple operation purposes are achieved.

Description

Technical Field

[0001] This invention relates to the field of physical measurement devices for metallic materials, specifically a metal thermal deformation measurement device and method based on the Hall effect. Background Technology

[0002] The thermal expansion characteristics of metallic materials are among their most important physical properties, directly affecting the design and operational stability of mechanical structures, precision instruments, and building engineering. Accurately measuring the thermal expansion of metals at different temperatures is crucial for material selection, product optimization, and fault prediction. Existing methods for measuring the thermal deformation of metals mainly include mechanical, optical, and electrical methods. Mechanical methods directly measure deformation using tools such as dial indicators and micrometers; while simple in structure, they have low measurement accuracy, are easily affected by mechanical friction and vibration, and struggle to accurately capture minute deformations. Optical methods, based on principles such as laser interferometry and grating diffraction, offer higher measurement accuracy, but the equipment is expensive, debugging is complex, and the measurement environment requires extremely high sealing and stability, making them unsuitable for on-site testing or complex operating conditions.

[0003] Among them, the Hall effect, as a typical electromagnetic induction phenomenon, has been used to detect physical quantities such as displacement and magnetic field. However, when applied to the measurement of thermal expansion of metals, existing devices have obvious defects, such as poor adaptability of connection structure. The connection between Hall element and metal rod is mostly fixed with clamps, which cannot be flexibly adjusted according to the size and shape of the metal rod, and the connection gap is easy to produce, resulting in distortion of deformation transmission.

[0004] Therefore, there is an urgent need for a Hall effect-based metal thermal deformation measurement device with strong adaptability and high measurement accuracy to make up for the shortcomings of existing technologies.

[0005] This case arose in order to resolve the aforementioned issues. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a metal thermal deformation measurement device and method based on the Hall effect, which is suitable for the accurate detection of thermal expansion of metal materials under different temperature environments, and solves the problems mentioned in the background technology.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a metal thermal deformation measurement device based on the Hall effect, comprising a metal linear expansion coefficient testing instrument with a metal rod to be tested inserted therein, a Hall element, and a Hall effect testing instrument, characterized in that: the metal linear expansion coefficient testing instrument is placed vertically, the Hall element is placed horizontally and connected to the metal striker of the metal linear expansion coefficient testing instrument via a connecting clip, the Hall element is adjusted to the magnetic field region where the change in Hall voltage and the change in Hall element displacement are linearly correlated after calibration by a calibration component, the connecting clip converts the longitudinal position of the metal striker into the longitudinal position change of the Hall element in the magnetic field, and its end is restricted to longitudinal movement only by a positioning component.

[0008] As a preferred embodiment, the metal linear expansion coefficient testing instrument further includes a device for controlling and displaying temperature and a heating element. The heating element has a hole on its side for inserting a metal rod and isolates the metal rod from the outside world. The metal striker is located on the upper side of the metal linear expansion coefficient testing instrument.

[0009] As a preferred embodiment, the connecting clip is further provided with a circular groove at the center of its lower part for connecting and fixing the metal striker of the metal linear dilatator, and a square groove on its side for fixing the Hall element.

[0010] As a preferred embodiment, the positioning part is further shaped as a semi-circle with a thickness, and a square groove is provided in the middle for fixing the connecting clip, and it is placed on the upper side of the longitudinal metal linear expansion coefficient testing instrument.

[0011] As a preferred embodiment, the calibration component is further provided with a square groove at the bottom to hold the vernier caliper of the Hall effect experimental instrument, and multiple equally spaced slots are provided at the top of the calibration component, and any slot is selected to hold one end of the Hall element for calibration experiment.

[0012] As a preferred embodiment, the device further includes a resistive element VA characteristic tester, an operational amplifier and its power supply. The Hall effect tester is connected to the Hall element and connected to the resistive element VA characteristic tester and the operational amplifier. The operational amplifier includes a μA741 type operational amplifier, multiple different types of resistors and fine-tuning resistors. The Hall voltage signal input to the Hall effect tester is amplified by the operational amplifier and then displayed by the resistive element VA characteristic tester.

[0013] As a preferred embodiment, the bottom of the metal linear expansion coefficient testing instrument is further positioned vertically. The part is fixed by a horizontal base.

[0014] A measurement method for a metal thermal deformation measuring device based on the Hall effect, comprising: The following steps are required: S1. Conduct calibration experiments: Determine that the Hall voltage change is most significant in a uniform magnetic field. Position: Use the same model Hall element on one side of the vernier caliper and adjust it to the calibrated uniform magnetic field position. Adjust the Hall element on the right side, which is connected to the linear expansion coefficient test instrument, so that its position is aligned with the Hall element on the left side.

[0015] The calibrated uniform magnetic field is located at the point where an electromagnet generates a magnetic field between its N and S poles after being energized. In the calibration experiment, the Hall element is moved, and the change in Hall voltage with the position of the Hall element is observed. When the change in Hall voltage is linearly correlated with the change in the displacement of the Hall element, the magnetic field region where the Hall element is located is the uniform magnetic field. S2. Connecting the Instruments: Turn on the power. Connect the DC regulated power supply to the positive terminal of the operational amplifier, and the negative terminal to... Connect the Hall element to the ground wire, then adjust the DC regulated power supply, use the Hall voltage as the input signal, connect the positive terminal to pin 2 of the operational amplifier, connect the negative terminal to the ground wire, connect the output signal to the positive terminal of the voltmeter of the resistance VA characteristic experiment instrument, connect the negative terminal of the voltmeter to the ground wire, connect the Hall element to the Hall effect experiment instrument, and ensure that the Hall element is connected correctly and prevent it from becoming loose. S3. Installation Materials: Connect the Hall element to the Hall effect experimental instrument, ensuring the Hall element connection is correct. To ensure and prevent loosening; connect the metal linear expansion coefficient tester to the experiment: first, use the printed horizontal base to fix its base, ensuring that the linear expansion coefficient tester is vertical, then insert one end of the Hall element horizontally into the connecting clip, connect the bottom of the connecting clip to the metal striker of the metal linear expansion coefficient tester, place the outside of the connecting clip into the square groove of the positioning part, and place the positioning part on the metal linear expansion coefficient tester. S4. Adjust experimental parameters: including the excitation current and Hall current of the Hall effect experimental instrument to provide an experimental environment for the Hall element in the magnetic field, adjust the temperature of the metal linear expansion coefficient test instrument 1, and the range of the voltmeter of the resistance element VA characteristic experimental instrument, and finally record the experimental data.

[0016] By adopting the above technical solution, the metal thermal deformation measuring device and method based on the Hall effect provided by the present invention have the following advantages compared with the prior art: 1. The design of calibration parts facilitates the positioning and movement of the Hall element in the Y-axis direction for calibration experiments and analysis. By moving the Hall element and observing the change of Hall voltage with the position of the Hall element, the magnetic field region where the change of Hall voltage and the change of Hall element displacement are linearly correlated can be obtained—that is, the uniform magnetic field. This allows small voltage changes to accurately reflect displacement changes, ensuring the accuracy of the expansion coefficient calculation. (Through the system calibration experiment, the optimal operating position of the Hall element (0X, 27Z) was determined, and the point where the Hall voltage change is most obvious was found to be (25X, 27Z), enabling the Hall element to achieve high-sensitivity measurement of small displacement changes at this point.)

[0017] 2. By using connecting clips, the metal striker and Hall element of the metal linear expansion coefficient testing instrument can be connected, directly converting the longitudinal position change of the metal striker into the longitudinal position change of the Hall element in the magnetic field. Simultaneously, by designing positioning components, the Hall element can be fixed in its position during calibration experiments when a linear correlation between the Hall element and the Hall voltage displacement is found experimentally; this also prevents lateral displacement of the Hall element due to environmental influences.

[0018] 3. Considering the friction between the metal rod and the inner wall of the experimental instrument, our group improved the vertical placement of the linear expansion coefficient testing experimental instrument and fixed it with a self-designed horizontal base, which effectively reduced the friction between the metal rod and the inner wall of the experimental instrument and further improved the measurement accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the present invention; Figure 2 This is a schematic diagram showing the assembly location of the Hall element in this invention; Figure 3 This is a schematic diagram of the connection card structure of the Hall element of the present invention; Figure 4 This is a schematic diagram of the positioning component structure of the Hall element of the present invention; Figure 5 This is a schematic diagram of the calibration component structure of the present invention; Figure 6 This is a schematic diagram of the horizontal base structure of the present invention; Figure 7 This is a schematic diagram of the operational amplifier of the present invention; Figure 8 This is a data fitting diagram of the YZ axes under the condition that the X-axis remains unchanged in this invention; Figure 9 This is a data fitting diagram of the YZ axis under the condition that the Z axis remains unchanged in this invention; Figure 10 The fitting plot of the data calibrated within a small range for this invention, input into the Origin table; Figure 11 This is a schematic diagram illustrating the relationship between Hall voltage difference and temperature according to the present invention; Figure 12 The Origin table fit was used for the experimental data of the conventional dial gauge as a control example of this invention.

[0020] In the diagram, 1. Metal linear expansion coefficient tester; 2. Heating element; 3. Connecting clip; 4. Positioning part; 5. Hall element; 6. Hall effect tester; 7. Calibration part; 8. Resistor element VA characteristic tester; 9. Operational amplifier power supply; 10. Operational amplifier; 11. μA741 operational amplifier; 12. Resistor; 13. Fine-tuning resistor; 14. Horizontal base. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0022] See appendix Figure 1-6 As shown, a metal thermal deformation measurement device based on the Hall effect includes a metal linear expansion coefficient testing instrument 1 (FD-LEA-B type), which is placed vertically to save space and reduce friction caused by horizontal placement of the experimental instrument, thus reducing errors. It includes a temperature control and display device and a heating element 2. The heating element 2 has a hole on its side for placing a metal rod, isolating the metal rod from the outside environment. A metal striker is also present. The metal rod is heated on the heating element 2.

[0023] The Hall effect experimental instrument 6 (HLD-HLZ-IV type) includes a device for controlling and displaying Hall voltage, operating current and excitation current, as well as a device for providing a magnetic field, used to set the excitation current and operating current for Hall effect experiments.

[0024] In this scenario, the metal linear expansion coefficient testing instrument 1 is the core of mechanical-temperature control for physical expansion. It forms a "temperature-expansion-electrical signal" relationship with the Hall effect testing instrument 6: the former is responsible for accurately controlling the temperature, transmitting expansion displacement and providing a calibration benchmark, while the latter converts the displacement into an electrical signal and completes data acquisition through the Hall effect. The two work together to achieve high-precision measurement of the metal linear expansion coefficient.

[0025] The calibration part 7 has a square groove at the bottom to hold the vernier caliper of the Hall effect experimental instrument 6; it has multiple equally spaced slots (2mm apart) at the top, and any number of slots can be selected to hold the Hall element 5 for calibration experiments.

[0026] The connecting clip 3 serves as a medium for the metal linear expansion coefficient testing instrument 1 to fit the cross-section of the Hall element 5. It has a circular groove in the center at the bottom for connecting and fixing the metal striker of the instrument 1, and a square groove on the side for fixing the Hall element 5. When the temperature rises or falls, the connecting clip 3 causes the Hall element 5 to change position in the magnetic field, thus causing a change in the magnetic field. This converts the minute expansion of the metal rod into a Hall voltage, facilitating quantitative analysis.

[0027] When in use, since the metal linear expansion coefficient test instrument 1 is normally placed—that is, horizontally placed—the metal striker pushes the Hall element 5 to move laterally, which does not cause a change in the Hall voltage. Therefore, the metal linear expansion coefficient test instrument 1 is placed vertically, and the connecting clip 3 connects the metal striker and the Hall element 5 of the metal linear expansion coefficient test instrument 1. After the metal rod is heated in the metal linear expansion coefficient test instrument 1, it deforms, which causes the metal striker to change in the vertical position. The connecting clip 3 converts the change in the vertical position of the metal striker into the change in the vertical position of the Hall element 5 in the magnetic field.

[0028] The Hall element 5 is fixed by the connecting clip 3, which provides a more secure connection between the metal rod and the Hall element 5. This ensures that the Hall element 5 remains stable in the magnetic field, is centered and perpendicular to the magnetic field, and prevents lateral swaying during the ascent of the metal rod, reducing experimental errors caused by swaying and further refining the experimental results. The positioning part 4 is semi-circular with a certain thickness and a square groove in the middle to fix the connecting clip 3, preventing environmental influences from affecting experimental accuracy. In the calibration experiment, it was found that the change in Hall voltage and the change in Hall element displacement are linearly correlated at a certain position. The positioning part 4 fixes the Hall element 5 in this position and also prevents the Hall element 5 from shifting due to environmental influences during the experiment.

[0029] Appendix Figure 7 In this circuit, operational amplifier 10 includes a μA741 operational amplifier 11, various resistors 12, a fine-tuning resistor 13, and a voltage supply device. The input Hall voltage is amplified by operational amplifier 10, and the amplified Hall voltage is displayed by a resistor element VA characteristic experimental instrument 8. The core working principle of operational amplifier 10 is based on differential amplification and feedback control mechanisms. Ideally, the open-loop gain of operational amplifier 10 approaches infinity, resulting in two main characteristics: "virtual short" (the voltages at the non-inverting and inverting input terminals are approximately equal) and "virtual open" (the current flowing into the input terminal is approximately zero). By introducing negative feedback into the circuit, the output signal can be fed back to the input terminal, stabilizing the amplification factor and enabling various signal processing operations.

[0030] Considering the very small deformation of the metal rod, the displacement of Hall element 5 is also very small, and the resulting Hall voltage change cannot be displayed on the Hall effect experimental instrument 6. Therefore, an operational amplifier 10 is needed to amplify the Hall voltage. The Hall voltage signal input to Hall effect experimental instrument 6 can be amplified by operational amplifier 10 and then output to the resistor element VA characteristic experimental instrument 8 for display, which cleverly greatly improves the accuracy of this experiment.

[0031] After connecting the operational amplifier, a UTP3703 DC regulated power supply is used to provide operating power to the μA741 operational amplifier. The specific wiring procedure is as follows: Precisely connect the power supply output to the positive power supply pin (VCC, corresponding to pin 7), negative power supply pin (VEE, corresponding to pin 4), and system ground (GND) of the operational amplifier to construct a complete power supply circuit. Use a 10KΩ resistor R1 and a 680KΩ resistor R2; therefore, R1 / R2 should be connected at 10KΩ, theoretically resulting in a gain of 680 / 10 = 68 times. After wiring, precisely calibrate the power supply by adjusting the voltage adjustment knob to stabilize the output DC voltage at 9.0V, ensuring it matches the typical operating voltage parameters of the μA741 operational amplifier. Connect a DuPont wire to the V1 ground line to short-circuit this path. Connect a multimeter to the output signal terminal and adjust the adjustable resistor until the voltage is zero. Next, apply a 0.1V voltage to the input signal terminal. If the multimeter detects an output voltage of approximately 6.8V, then the operational amplifier circuit is correctly constructed and the experiment can be conducted.

[0032]

[0033] Experimental calculations showed that the actual amplification factor of the operational amplifier was 58 times. A second experiment was conducted, and the Hall voltage changed as indicated by the volt-ampere characteristic tester. The formal experiment then commenced.

[0034] The working principle of this technical solution is as follows: First, the metal rod to be tested is placed in the metal linear expansion coefficient testing instrument 1. Then, the connecting clip 3 is connected to the Hall element 5 and the metal striker of the metal linear expansion coefficient testing instrument 1. At the same time, the position of the Hall element 5 is adjusted to the optimal experimental position obtained from the calibration experiment and fixed using the positioning part 4. Finally, the Hall effect testing instrument 6, the resistance element VA characteristic testing instrument 8, and the operational amplifier 10 are connected. The temperature, excitation current, and operating current are set. The metal rod deforms due to heat, affecting the displacement of the Hall element 5 in the uniform magnetic field through the connecting clip 3, causing a change in the Hall voltage. The Hall voltage is amplified by the operational amplifier 10 and displayed by the resistance element VA characteristic testing instrument 8.

[0035] Displacement calibration: The linear metal expansion instrument is equipped with a dial gauge ( Figure 2The unlabeled structure on the far right (i.e., the dial gauge) can be used to calibrate the relationship between Hall voltage and displacement before the experiment, establishing a quantitative correspondence between Hall voltage changes and actual expansion.

[0036] The measurement method of the measuring device includes the following steps: 1. Conduct a calibration experiment to determine where the Hall voltage of Hall element 5 changes most significantly in a uniform magnetic field: Use the same model of Hall element 5 on one side of the vernier caliper and adjust it to the optimal uniform magnetic field position determined by calibration. Adjust the Hall element 5 on the right side connected to the linear expansion coefficient test instrument so that its position is aligned with the Hall element 5 on the left side. When an electromagnet is energized, it generates a magnetic field between its N and S poles. In the calibration experiment, the Hall element 5 is moved (the Hall element 5 is moved at 2mm intervals along the Y-axis of the calibration part 7 to facilitate calibration analysis). The Hall voltage is observed to change with the position of the Hall element 5. When the change of the Hall voltage is linearly correlated with the change of the displacement of the Hall element 5, the magnetic field region where the Hall element 5 is located is a uniform magnetic field. 2. Turn on the power supply. Connect the DC regulated power supply to the positive terminal, negative terminal, and ground of the operational amplifier 10. Then adjust the DC regulated power supply to 9V. Use the Hall voltage as the input signal. Connect the positive terminal to pin 2 of the operational amplifier 10 and the negative terminal to the ground. Connect the output signal to the positive terminal of the voltmeter of the 12V-A characteristic experiment instrument. Connect the negative terminal of the voltmeter to the ground. 3. Connect Hall element 5 to Hall effect experimental instrument 6, ensuring correct wiring of Hall element 5 and preventing loosening; connect metal linear expansion coefficient test instrument 1 to the experiment: first, use the printed horizontal base 14 to fix its base, ensuring that metal linear expansion coefficient test instrument 1 is vertical, insert one end of Hall element 5 horizontally into connecting clip 3, connect the bottom of connecting clip 3 to the metal striker of metal linear expansion coefficient test instrument 1, place the outside of connecting clip 3 into the square groove of positioning part 4, and place positioning part 4 on metal linear expansion coefficient test instrument 1; 4. Adjust key experimental parameters: Set the excitation current of the Hall effect experimental apparatus 6 to 500mA and the Hall current to 2.00mA to provide an optimal experimental environment for the Hall element 5 in the magnetic field. Set the temperature of the metal linear expansion coefficient testing apparatus 1 to 60℃ and adjust the voltmeter range of the resistance element VA characteristic experimental apparatus 8 to 2V. Record the experimental data for subsequent analysis. and The functional relationship provides specific data.

[0037] The calibration experiment in step 1 is specifically performed as follows: (a) A calibration experiment was conducted under the conditions of a Hall current of 2.00 mA, an excitation current of 0.5 A, and a fixed X-axis. Specific data are shown in the table below: YZ axis calibration test data

[0038] (II) A calibration experiment was conducted under the conditions of a Hall current of 2.00 mA, an excitation current of 0.5 A, and a fixed Y-axis. Specific data are shown in the table below: YZ axis calibration test data

[0039] Analyzing the above data, using Origin tables, a fitting plot was created. The function corresponding to the Z and Y axes was analyzed to determine the location where the Hall voltage change was most significant. The position with the largest ratio is the position with the largest slope (see Appendix). Figure 7 , 8 ).

[0040] Analysis of the graph data reveals that the slope of the Hall voltage formula for Hall element 5 is greatest at 27mm on the z-axis, the slope of the Hall voltage formula for Hall element 5 is greatest in the x-axis range [20mm, 30mm], and the slope of the Hall voltage variation formula with height is greatest at 0mm on the opposite y-axis, indicating the most significant change in Hall voltage.

[0041] Based on the above data, when a Hall current of 2mA and an excitation current of 0.5A are applied to the device, the Hall element 5 is positioned at 27mm along the z-axis, 25mm along the x-axis, and 0mm in the opposite y-axis direction. At this point, the Hall sensor exhibits optimal sensitivity, the Hall voltage change is most pronounced, and the experimental results are optimal and most accurate.

[0042] Because the Hall element 5 moved less than 1 mm during the experiment, a small magnetic field was required, specifically within the z-axis range (26.2 mm ~ 27.3 mm). Furthermore, due to the limited range, the Hall voltage display accuracy on the Hall effect experimental apparatus 6 was insufficient; therefore, a digital amplifier was connected to measure the voltage again within this range. Specific data are shown in the table below.

[0043] The data from the small-scale calibration were used to generate a fitting plot in an Origin table (see appendix). Figure 9 ), and then obtain The value of .

[0044] Repeat the data measurements as shown in the table below (and simultaneously plot the relationship between Hall voltage difference and temperature, see appendix). Figure 10 ).

[0045]

[0046] By analyzing the fitting graph of Hall voltage difference and temperature (attached) Figure 10 ): y=0.0015x-0.0324 R² = 0.99195 The relationship between ΔU and ΔT is obtained, K=0.0015 This example uses a traditional experimental measurement as a control. A traditional dial gauge experiment was conducted using the same instrument and under the same conditions. Specific data are shown in the table below.

[0047] The experimental data were analyzed using Origin table fit analysis to obtain... The functional relationship is shown in the appendix. Figure 11 As shown, by analyzing the fitting plot, we obtain... =0.00858, goodness of fit r=0.99925.

[0048] Measurement results (Innovation Law): Precision K J =0.16473 mm The derivation formula for this experiment is as follows:

[0049] Through experimental measurement, it was determined that the metal rod inside the FD-LEA-B linear expansion system testing apparatus was processed to a diameter of... Specifications: 8mm in diameter, 400mm in length. Substitute the above data into:

[0050] (Traditional Law): Substitute into the formula for the coefficient of linear expansion:

[0051] Innovative vs. Traditional: α 铝 =2.3×10 -5 ℃ -1

[0052]

[0053] α1 is the linear expansion coefficient of metal using the traditional method, and α2 is the linear expansion coefficient of metal using the innovative method. The comparison shows that the innovative method is more accurate.

[0054] Error Analysis This experiment primarily uses linear regression and curve fitting to analyze the data. The least squares method is a technique that finds the best fit by minimizing the sum of squared errors. Therefore, the least squares method is chosen as the optimal error analysis method.

[0055] formula:

[0056] Function fit Standard deviation n1: of the records Number of data sets m1: Slope R2 of the function: Function fit Standard deviation n²: of the records Number of data sets m2: function slope Substituting the data: R1=0.99195, n1=11, m1=0.99195 R² = 0.94715 n² = 11 m² = 0.16473

[0057] Based on the above results, the error in the coefficient of linear expansion is:

[0058] Experimental results show that our group used a 400 mm aluminum rod as the sample and conducted measurements within the temperature range of 30–60℃. Based on the Hall effect, a non-contact measurement method successfully converted the minute thermal expansion displacement of the metal rod into a Hall voltage, which was then calculated using the linear expansion coefficient formula. The measured linear expansion coefficient of the aluminum rod was 2.28 × 10⁻⁶. -5 / ℃, compared to the traditional method (2.145×10 -5 / ℃), the traditional dial indicator method offers some improvement in accuracy, getting closer to the theoretical value of aluminum (2.3×10). -5 / ℃). This achievement fully demonstrates the significant advantage of the Hall effect-based measurement method in terms of accuracy, effectively overcoming the problems of reading parallax and large errors existing in traditional measurement methods (dial gauge method), and providing a new technical approach for the accurate measurement of the coefficient of linear expansion of metals. The innovative method can realize data visualization, perform directional analysis, and reduce errors caused by operational mistakes.

[0059] This embodiment significantly improves the detection capability of weak electrical signals by introducing an operational amplifier 10 to amplify the Hall voltage. With a magnification factor of 54, the microvolt-level Hall voltage is amplified to a more easily measurable and analyzable range (millivolt level), providing reliable data support for accurately obtaining the coefficient of linear expansion of metals. The core function of the operational amplifier 10 in the experiment is to convert the weak and easily interfered Hall signal into a stable and measurable strong signal, providing accurate data for measuring the linear expansion of metals through its amplification function.

[0060] Furthermore, the optimal operating point (0) of Hall element 5 was determined through system calibration experiments. X 27 Z The point where the Hall voltage change was most significant was found to be (25). X 27 Z This enables the Hall element 5 to achieve highly sensitive measurement of minute displacement changes at that point.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for measuring the thermal deformation of metals based on the Hall effect, comprising a metal linear expansion coefficient testing instrument with a metal rod to be tested inserted therein, a Hall element, and a Hall effect testing instrument, characterized in that: The metal linear expansion coefficient testing instrument is placed vertically, and the Hall element is placed horizontally with one end connected to the metal striker of the metal linear expansion coefficient testing instrument via a connecting clip. The other end of the Hall element is connected to a calibration component, and after calibration, it is adjusted to the magnetic field region where the change in Hall voltage and the change in Hall element displacement are linearly correlated. The connecting clip converts the longitudinal position of the metal striker into the longitudinal position change of the Hall element in the magnetic field, and the end of the connecting clip is restricted by a positioning component.

2. The metal thermal deformation measuring device based on the Hall effect according to claim 1, characterized in that: The metal linear expansion coefficient testing instrument includes a device for controlling and displaying temperature and a heating element. The heating element has a hole on its side for inserting a metal rod and isolates the metal rod from the outside. The metal striker is located on the upper side of the metal linear expansion coefficient testing instrument.

3. The metal thermal deformation measuring device based on the Hall effect according to claim 2, characterized in that: The connecting clip has a circular groove at the center of its lower part to connect the metal striker of the metal linear dilatator, and a square groove on its side to fix the Hall element.

4. The metal thermal deformation measuring device based on the Hall effect according to claim 3, characterized in that: The positioning part is a semi-circle with thickness, and a square groove is provided in the middle for fixing the connecting clip, and it is placed on the upper side of the longitudinal metal linear expansion coefficient tester.

5. The metal thermal deformation measuring device based on the Hall effect according to claim 1, characterized in that: The calibration component has a square groove at its bottom to hold the vernier caliper of the Hall effect experimental instrument. The calibration component has multiple equally spaced slots at its top, and any slot can be selected to hold one end of the Hall element for calibration experiments.

6. The metal thermal deformation measuring device based on the Hall effect according to claim 1, characterized in that: It also includes a resistive element VA characteristic tester, an operational amplifier and its power supply. The Hall effect tester is connected to the Hall element and connected to the resistive element VA characteristic tester and the operational amplifier. The operational amplifier includes a μA741 type operational amplifier, multiple different types of resistors and fine-tuning resistors. The Hall voltage signal input to the Hall effect tester is amplified by the operational amplifier and then displayed by the resistive element VA characteristic tester.

7. The metal thermal deformation measuring device based on the Hall effect according to claim 1, characterized in that: The metal linear expansion coefficient testing instrument, which is placed vertically, is fixed at the bottom by a horizontal base.

8. The measurement method of the measuring device based on the Hall effect for measuring the thermal deformation of metals according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Conduct calibration experiments: Determine that the Hall voltage change is most significant in a uniform magnetic field. Position: Use the same model Hall element on one side of the vernier caliper and adjust it to the calibrated uniform magnetic field position. Adjust the Hall element on the right side, which is connected to the linear expansion coefficient test instrument, so that its position is aligned with the Hall element on the left side. S2. Connecting the Instruments: Turn on the power. Connect the DC regulated power supply to the positive terminal of the operational amplifier, and the negative terminal to... Connect the power supply to the ground wire, then adjust the DC regulated power supply, use the Hall voltage as the input signal, connect the positive terminal to pin 2 of the operational amplifier, connect the negative terminal to the ground wire, connect the output signal to the positive terminal of the voltmeter of the resistor VA characteristic experiment instrument, and connect the negative terminal of the voltmeter to the ground wire. S3. Installation Materials: Connect the Hall element to the Hall effect experimental instrument, ensuring the Hall element connection is correct. To ensure and prevent loosening; connect the linear expansion coefficient tester to the experiment: first, use the printed horizontal base to fix its base, ensuring that the linear expansion coefficient tester is vertical, then insert one end of the Hall element horizontally into the connecting clip, connect the bottom of the connecting clip to the metal striker of the metal linear expansion coefficient tester, place the outside of the connecting clip into the square groove of the positioning part, and place the positioning part on the metal linear expansion coefficient tester. S4. Adjust experimental parameters: including the excitation current and Hall current of the Hall effect experimental instrument to provide an experimental environment for the Hall element in the magnetic field, adjust the temperature of the linear expansion coefficient test instrument, and adjust the range of the voltmeter of the resistance element VA characteristic test instrument, and finally record the experimental data.

9. The measurement method of the measuring device based on the Hall effect for measuring the thermal deformation of metals according to claim 8, characterized in that: The position of the uniform magnetic field calibrated in step S1 is that a magnetic field is generated between the N and S poles of the electromagnet after it is energized. In the calibration experiment, the Hall element is moved and the change of Hall voltage with the position of Hall element is observed. When the change of Hall voltage is linearly correlated with the change of Hall element displacement, it is a uniform magnetic field.

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