Fuse mechanical parameter calibration device and initial elastic force calibration method

Abstract

The invention discloses a fuse mechanical parameter calibration device and an initial elastic force calibration method, fuse mechanical parameters are accurately and efficiently calibrated through the fuse mechanical parameter calibration device, then the initial elastic force of a fuse is accurately calculated through the initial elastic force calibration method, and a large number of calibration tests are avoided. The parameter preparation workload of fuse tension measurement is remarkably shortened, the problem that force value measurement and displacement measurement cannot be considered at the same time is solved, the mechanical characteristics of the fuse can be calibrated, the mechanical parameters can be optimally estimated, high-precision quantitative detection can be performed on the tension of the fuse in an installation scene, and the safety of the fuse is improved. Therefore, the problem that the tension of the fuse is difficult to measure in the current industrial production is solved, the anti-loose performance of the fuse is ensured, and the anti-loose failure caused by excessive looseness or tension of the fuse is avoided.

Description

Technical Field

[0001] This invention belongs to the technical field of fuse spring force calibration, specifically relating to a fuse mechanical parameter calibration device and an initial spring force calibration method. Background Technology

[0002] In the field of aerospace manufacturing, fastener anti-loosening is a very important issue due to the large vibrations that occur during aircraft flight and takeoff and landing. Fuse connection anti-loosening is widely used because of its simple structure, light weight and non-destructive nature, and occupies a major position in the anti-loosening of various aircraft systems.

[0003] However, the testing of fuse connection performance is still in a relatively primitive stage. For tension testing related to anti-loosening performance, observation and manual pushing methods are commonly used. The observation method requires that the fuse between the two locked fasteners be in a straight line along its path in its natural state; the manual pushing method requires that the fuse should not be moved when flicked with a single finger. Quantitative testing methods are lacking, and different testing standards should be applied to fuses of different lengths and diameters, but current testing methods in this field are somewhat deficient.

[0004] In summary, current methods for testing the tension of anti-loosening fuses lack a quantitative tool for fuse tension testing, which is not conducive to the accurate control and evaluation of anti-loosening performance and makes it impossible to establish a practical standard for fuse anti-loosening inspection. Therefore, this invention discloses a fuse mechanical parameter calibration device and an initial elasticity calibration method. Summary of the Invention

[0005] This invention discloses a fuse mechanical parameter calibration device and an initial elasticity calibration method, which can calibrate the mechanical characteristics of the fuse and make optimal estimates of the mechanical parameters. It can also perform high-precision quantitative detection of the fuse tension in the installation scenario, thereby solving the problem that it is difficult to measure the tension of fuses in current industrial production, ensuring the anti-loosening performance of the fuse, and avoiding anti-loosening failure caused by excessive loosening or tension of the fuse.

[0006] This invention is achieved through the following technical solution:

[0007] A fuse mechanical parameter calibration device includes a calibration base. A force-applying slider and a force-measuring slider are slidably disposed on the top of the calibration base along a first direction. A pressure sensor is disposed on the side of the force-measuring slider near the force-applying slider. A first driving device is disposed at the bottom of the force-applying slider to move the force-applying slider along the first direction. A fuse is disposed between the tops of the force-applying slider and the force-measuring slider. A digital force gauge and a digital dial indicator are disposed between the force-applying slider and the force-measuring slider along a second direction perpendicular to the first direction. The digital force gauge and the digital dial indicator are respectively disposed on both sides of the fuse along the second direction.

[0008] To better realize the present invention, the bottom of the digital force gauge is further provided with a second slide rail along the second direction, the bottom of the digital force gauge is slidably connected to the second slide rail, and the bottom of the digital force gauge is provided with a second driving device to drive the digital force gauge to move along the second direction.

[0009] To better realize the present invention, the top of the calibration base is further provided with first slide rails at both ends along the first direction, and the bottoms of the force-applying slider and the force-measuring slider are respectively slidably connected to the first slide rails.

[0010] To better realize the present invention, the first driving device further includes a first nut and a first lead screw. The first nut is fitted on the outside of the first lead screw. The first nut is connected to the force-applying slider. The first lead screw is rotatably mounted on the calibration base in a first direction.

[0011] To better realize the present invention, the second driving device further includes a second nut and a second lead screw. The second nut is fitted on the outside of the second lead screw. The second nut is connected to a digital force gauge. The second lead screw is rotatably mounted on a calibration base in a second direction.

[0012] A method for calibrating the initial spring force of a fuse includes the following steps:

[0013] Step 1: Use a fuse mechanical parameter calibration device to calibrate the midpoint displacement of the fuse under different forces;

[0014] Step 2: Calculate the best estimate of the elastic coefficient of the fuse based on the initial tension, reaction force, and midpoint displacement of the fuse;

[0015] Step 3: Select reference points symmetrically on both sides of the fuse midpoint. Use a tension / compression force gauge to apply force to the fuse midpoint until the displacement of the fuse midpoint reaches the calibrated value. Then, read the readings of the two probes of the tension / compression force gauge at the reference points on both sides.

[0016] Step 4: Measure the distance between the reference point and the midpoint of the fuse. The distance between the reference point and the midpoint of the fuse, the displacement of the midpoint of the fuse, and the reading at the reference point are used to calibrate the length of the fuse.

[0017] Step 5: Calculate the initial tension of the fuse based on the calibrated fuse length, the best estimate of the elastic coefficient, and the displacement of the fuse's midpoint.

[0018] To better realize the present invention, step 2 further includes:

[0019] Step 2.1: Establish the expression for the fuse tension with respect to the reaction force, midpoint displacement, and elastic coefficient;

[0020] Step 2.2: Use the least squares method to process the expression and back-calculate the best estimate of the elasticity coefficient.

[0021] To better realize the present invention, the expression established in step 2.1 is further as follows:

[0022]

[0023] Where: T represents the initial spring force of the fuse; F represents the reaction force at the midpoint of the fuse; δ represents the displacement at the midpoint; L represents the length of the fuse; and k represents the spring constant.

[0024] To better realize the present invention, step 2.2 further includes:

[0025] make The least squares method is used to obtain:

[0026]

[0027] Where: n represents the total number of sets of Fi and Ti collected; Fi represents the lateral force collected in the i-th collection; Ti represents the fuse tension generated in the i-th collection.

[0028] To better realize the present invention, the optimal estimate of the elastic coefficient of the fuse is further:

[0029]

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] This invention calibrates and optimally estimates the mechanical parameters of a fuse, thereby ensuring the reliability and accuracy of the final initial tension calibration. Simultaneously, the invention calibrates the elastic coefficient of the fuse using a dedicated fuse mechanical parameter calibration device and determines the optimal estimates of multiple sets of parameters using the least squares method, significantly improving the accuracy of fuse tension calculation. By determining the elastic coefficient of the fuse through calibration and combining it with parameters such as fuse length, on-site measured reaction force, and midpoint displacement, the invention calculates the fuse tension, achieving high-precision quantitative measurement of fuse tension—a breakthrough improvement compared to traditional tactile estimation. Furthermore, the combination of experimental calibration and modeling calculation avoids numerous calibration experiments, significantly reducing the workload of parameter preparation for fuse tension measurement. The invention also incorporates two dial gauges in the fuse tension measuring device, using their readings to determine the fuse midpoint—a simple and easy process. Converting the dial gauge readings to midpoint displacement solves the problem of not being able to simultaneously measure force and displacement. Attached Figure Description

[0032] Figure 1 A front view of a fuse mechanical parameter calibration device;

[0033] Figure 2 Top view of the fuse mechanical parameter calibration device;

[0034] Figure 3 This is a schematic diagram showing the installation of a tension / compression force gauge at the fuse.

[0035] Figure 4 This is a schematic diagram for calculating the initial tension.

[0036] Among them: 1. Bolt, 2. Digital dial indicator, 3. Digital force gauge, 4. Force-applying slider, 5. Force-measuring slider, 6. Dial indicator pin, 7. Force gauge pin, 8. Pressure sensor, 9. Limit block, 10. Second slide rail, 11. Handwheel, 12. First lead screw, 13. First slide rail. Detailed Implementation

[0037] Example 1:

[0038] This embodiment provides a fuse mechanical parameter calibration device, such as... Figure 1 and Figure 2As shown, the device includes a calibration base. A force-applying slider 4 and a force-measuring slider 5 are slidably mounted on the top of the calibration base along a first direction. A pressure sensor 8 is mounted on the side of the force-measuring slider 5 near the force-applying slider 4. A first driving device is mounted on the bottom of the force-applying slider 4 to move along the first direction. A fuse is mounted between the tops of the force-applying slider 4 and the force-measuring slider 5. A digital force gauge 3 and a digital dial indicator 2 are mounted between the force-applying slider 4 and the force-measuring slider 5 along a second direction perpendicular to the first direction. The digital force gauge 3 and the digital dial indicator 2 are respectively mounted on both sides of the fuse along the second direction.

[0039] The bottom of the digital force gauge 3 is provided with a second slide rail 10 along the second direction. The bottom of the digital force gauge 3 is slidably connected to the second slide rail 10. The bottom of the digital force gauge 3 is provided with a second driving device that drives the digital force gauge 3 to move along the second direction.

[0040] The top of the calibration base is provided with first slide rails 13 at both ends along the first direction, and the bottoms of the force-applying slider 4 and the force-measuring slider 5 are respectively slidably connected to the first slide rails 13.

[0041] The first driving device includes a first nut and a first lead screw 12. The first nut is fitted onto the outside of the first lead screw 12 and is connected to the force-applying slider 4. The first lead screw 12 is rotatably mounted on the calibration base in a first direction. The second driving device includes a second nut and a second lead screw. The second nut is fitted onto the outside of the second lead screw and is connected to the digital force gauge 3. The second lead screw is rotatably mounted on the calibration base in a second direction.

[0042] A fuse is fixed between the top of the force-applying slider 4 and the force-measuring slider 5 using bolt 1. The handwheel 11 at one end of the first lead screw 12 is turned, causing the force-measuring slider 5 to slide until it contacts the pressure sensor 8. At this point, the force-measuring slider 5 cannot continue to slide due to the restriction of the pressure sensor 8, while the force-applying slider 4 continues to slide away from the force-measuring slider 5 under the action of the first lead screw 12 until the fuse is tightened. The real-time tension of the fuse can then be detected by the pressure sensor 8. A limit block 9 is provided on the side of the pressure sensor 8 near the force-applying slider 4 to limit the sliding stroke of the pressure sensor 8 and the force-measuring slider 5.

[0043] When the digital force gauge pin 7 contacts the center of the fuse and the reading is exactly zero, the fuse remains unchanged. When the dial indicator pin 6 contacts the center of the fuse and the reading is exactly zero, the digital force gauge 3 is pressed against the fuse along the second direction on the second slide rail 10. The reading of the digital dial indicator 2 changes until it reaches the predetermined midpoint displacement. At this point, the position of the digital force gauge 3 is locked on the second guide rail 10. The data cables of the pressure sensor 8, digital force gauge 3, and digital dial indicator 2 are all connected to an external data acquisition card, allowing simultaneous data acquisition from all three.

[0044] Turning the handwheel 11 gradually increases the tension on the fuse, causing the pressure sensor 8 to gradually increase its reading. At the same time, the position of the locked digital force gauge 3 and the reading of the digital dial gauge 2 remain unchanged, and multiple sets of data are collected.

[0045] Example 2:

[0046] This embodiment of a fuse initial spring force calibration method includes the following steps:

[0047] Step 1: The midpoint displacement of the fuse under different forces is calibrated using a fuse mechanical parameter calibration device. Specifically, the fuse is fixed between the top of the force-applying slider 4 and the force-measuring slider 5 using bolt 1. The handwheel 11 at one end of the first lead screw 12 is turned, causing the force-measuring slider 5 to slide until it contacts the pressure sensor 8. At this point, the force-measuring slider 5 cannot continue to slide under the constraint of the pressure sensor 8, while the force-applying slider 4 continues to slide away from the force-measuring slider 5 under the action of the first lead screw 12 until the fuse is tightened. The real-time tension of the fuse can then be collected by the pressure sensor 8. A limit block 9 is provided on the side of the pressure sensor 8 near the force-applying slider 4 to limit the sliding stroke of the pressure sensor 8 and the force-measuring slider 5.

[0048] When the digital force gauge pin 7 contacts the center of the fuse and the reading is exactly zero, the fuse remains unchanged. When the dial indicator pin 6 contacts the center of the fuse and the reading is exactly zero, the digital force gauge 3 is pressed against the fuse along the second direction on the second slide rail 10. The reading of the digital dial indicator 2 changes until it reaches the predetermined midpoint displacement. At this point, the position of the digital force gauge 3 is locked on the second guide rail 10. The data cables of the pressure sensor 8, digital force gauge 3, and digital dial indicator 2 are all connected to an external data acquisition card, allowing simultaneous data acquisition from all three.

[0049] Turning the handwheel 11 gradually increases the tension on the fuse, causing the pressure sensor 8 to gradually increase its reading. At the same time, the position of the locked digital force gauge 3 and the reading of the digital dial gauge 2 remain unchanged, and multiple sets of data are collected.

[0050] Step 2: Calculate the best estimate of the elastic coefficient of the fuse based on the initial tension, reaction force, and midpoint displacement of the fuse;

[0051] The calibration process involves certain measurement errors, and the physical process also exhibits certain nonlinear disturbances. By collecting multiple sets of data and calculating the elastic coefficient using the least squares method, the accuracy of the calibration results can be improved. The calculation formula is as follows:

[0052]

[0053] Where: T represents the initial spring force of the fuse; F represents the reaction force at the midpoint of the fuse; δ represents the displacement at the midpoint; L represents the length of the fuse; and k represents the spring constant.

[0054] make:

[0055]

[0056] Using the least squares method, we can obtain:

[0057]

[0058] Where: n represents the total number of sets of Fi and Ti collected; Fi represents the lateral force collected in the i-th collection; Ti represents the fuse tension generated in the i-th collection.

[0059] After solving for a and b, the best estimate of the value of k can be calculated in reverse:

[0060]

[0061] Step 3: Select reference points symmetrically on both sides of the fuse midpoint, and apply a force to the fuse midpoint using a tension / compression force gauge. Figure 3 As shown, ensure the displacement of the fuse's midpoint reaches the calibrated value. Then, read the readings of the two probes of the tension / compression force gauge at the reference points on both sides. Using the tension / compression force gauge as shown, ensure the gauge pin contacts the fuse, with the pin forming a 90° angle with the first direction. Slightly push the force gauge until both the two symmetrical dial indicators on either side of the pin and the force gauge itself show readings. Adjust the contact position between the pin and the fuse until the two dial indicator readings on both sides are equal, indicating the force gauge pin is at the fuse's midpoint. Then, push the force gauge forward until both dial indicator readings are ε, and record the current reading F.

[0062] Step 4: Measure the distance between the reference point and the midpoint of the fuse. The distance between the reference point and the midpoint of the fuse, the displacement of the fuse's midpoint, and the reading at the reference point are used to calibrate the fuse's length. Figure 4 As shown, based on the trigonometric relationship, let the distance between the dial indicator needle and the force gauge needle be C. The relationship between the dial indicator reading ε and the displacement δ of the tension / compression force gauge is as follows:

[0063]

[0064] Step 5: Calculate the initial tension of the fuse based on the calibrated fuse length, the best estimate of the spring constant, and the midpoint displacement of the fuse. That is, the spring constant k has been obtained through calibration and the least squares method, the fuse length L is measured on-site, and the midpoint displacement δ is indirectly controlled by a dial indicator and read from the force gauge. The formula for calculating the initial fuse tension T is as follows:

[0065]

[0066] To better realize the present invention, step 2 further includes:

[0067] Step 2.1: Establish the expression for the fuse tension with respect to the reaction force, midpoint displacement, and elastic coefficient;

[0068] Step 2.2: Use the least squares method to process the expression and back-calculate the best estimate of the elasticity coefficient.

[0069] To better realize the present invention, the expression established in step 2.1 is further as follows:

[0070]

[0071] Where: T represents the initial spring force of the fuse; F represents the reaction force at the midpoint of the fuse; δ represents the displacement at the midpoint; L represents the length of the fuse; and k represents the spring constant.

[0072] To better realize the present invention, step 2.2 further includes:

[0073] make The least squares method is used to obtain:

[0074]

[0075] Where: n represents the total number of sets of Fi and Ti collected; Fi represents the lateral force collected in the i-th collection; Ti represents the fuse tension generated in the i-th collection.

[0076] To better realize the present invention, the optimal estimate of the elastic coefficient of the fuse is further:

[0077]

[0078] The rest of this embodiment is the same as any one of embodiments 1-3, so it will not be described again.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A device for calibrating the mechanical parameters of a fuse, comprising a calibration base, characterized in that, The top of the calibration base is slidably provided with a force-applying slider (4) and a force-measuring slider (5) along the first direction. A pressure sensor (8) is provided on the side of the force-measuring slider (5) near the force-applying slider (4). A first driving device is provided at the bottom of the force-applying slider (4) to drive the force-applying slider (4) to move along the first direction. A fuse is provided between the tops of the force-applying slider (4) and the force-measuring slider (5). A digital force gauge (3) and a digital dial indicator (2) are provided between the force-applying slider (4) and the force-measuring slider (5) along the second direction perpendicular to the first direction. The digital force gauge (3) and the digital dial indicator (2) are respectively provided on both sides of the fuse along the second direction.

2. The fuse mechanical parameter calibration device according to claim 1, characterized in that, The bottom of the digital force gauge (3) is provided with a second slide rail (10) along the second direction. The bottom of the digital force gauge (3) is slidably connected to the second slide rail (10). The bottom of the digital force gauge (3) is provided with a second driving device that drives the digital force gauge (3) to move along the second direction.

3. The fuse mechanical parameter calibration device according to claim 2, characterized in that, The top of the calibration base is provided with first slide rails (13) at both ends along the first direction, and the bottom of the force-applying slider (4) and the force-measuring slider (5) are slidably connected to the first slide rails (13).

4. The fuse mechanical parameter calibration device according to claim 3, characterized in that, The first driving device includes a first nut and a first lead screw (12). The first nut is fitted on the outside of the first lead screw (12). The first nut is connected to the force-applying slider (4). The first lead screw (12) is rotatably mounted on the calibration base in a first direction.

5. A fuse mechanical parameter calibration device according to claim 4, characterized in that, The second drive device includes a second nut and a second lead screw. The second nut is fitted on the outside of the second lead screw. The second nut is connected to a digital force gauge (3). The second lead screw is rotatably mounted on a calibration base in a second direction.

6. A method for calibrating the initial spring force of a fuse, implemented based on the fuse mechanical parameter calibration device according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Use a fuse mechanical parameter calibration device to calibrate the midpoint displacement of the fuse under different forces; Step 2: Calculate the best estimate of the elastic coefficient of the fuse based on the initial tension, reaction force, and midpoint displacement of the fuse; Step 3: Select reference points symmetrically on both sides of the fuse midpoint. Use a tension / compression force gauge to apply force to the fuse midpoint until the displacement of the fuse midpoint reaches the calibrated value. Then, read the readings of the two probes of the tension / compression force gauge at the reference points on both sides. Step 4: Measure the distance between the reference point and the midpoint of the fuse. The distance between the reference point and the midpoint of the fuse, the displacement of the midpoint of the fuse, and the reading at the reference point are used to calibrate the length of the fuse. Step 5: Calculate the initial tension of the fuse based on the calibrated fuse length, the best estimate of the elastic coefficient, and the displacement of the fuse's midpoint.

7. The method for calibrating the initial spring force of a fuse according to claim 6, characterized in that, Step 2 specifically includes: Step 2.1: Establish the expression for the fuse tension with respect to the reaction force, midpoint displacement, and elastic coefficient; Step 2.2: Use the least squares method to process the expression and back-calculate the best estimate of the elasticity coefficient.

8. The method for calibrating the initial spring force of a fuse according to claim 7, characterized in that, The expression established in step 2.1 is as follows: Where: T represents the initial spring force of the fuse; F represents the reaction force at the midpoint of the fuse; δ represents the displacement at the midpoint; L represents the length of the fuse; and k represents the spring constant.

9. The method for calibrating the initial spring force of a fuse according to claim 8, characterized in that, Step 2.2 specifically includes: make The least squares method is used to obtain: Where: n represents the total number of sets of Fi and Ti collected; Fi represents the lateral force collected in the i-th collection; Ti represents the fuse tension generated in the i-th collection.

10. The method for calibrating the initial spring force of a fuse according to claim 9, characterized in that, The optimal estimate of the spring constant of the fuse is:

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