CN114964595A - Method and device for measuring axial force of bolt - Google Patents
Method and device for measuring axial force of bolt Download PDFInfo
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- CN114964595A CN114964595A CN202210494823.9A CN202210494823A CN114964595A CN 114964595 A CN114964595 A CN 114964595A CN 202210494823 A CN202210494823 A CN 202210494823A CN 114964595 A CN114964595 A CN 114964595A
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- 238000000034 method Methods 0.000 title claims abstract description 50
- 238000012360 testing method Methods 0.000 claims abstract description 124
- 238000012544 monitoring process Methods 0.000 claims description 28
- 230000000712 assembly Effects 0.000 claims description 22
- 238000000429 assembly Methods 0.000 claims description 22
- 238000005498 polishing Methods 0.000 claims description 4
- 238000003556 assay Methods 0.000 claims description 3
- 238000007781 pre-processing Methods 0.000 claims description 3
- 230000000875 corresponding effect Effects 0.000 description 13
- 238000005259 measurement Methods 0.000 description 8
- 238000012545 processing Methods 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002173 cutting fluid Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
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- 230000004048 modification Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
- G01M5/0075—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by means of external apparatus, e.g. test benches or portable test systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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Abstract
The application relates to a method and a device for measuring axial force of a bolt, and relates to the technical field of mechanical parts. The method comprises the steps of selecting at least two bolts as test bolts, sequentially applying at least two loading forces with different sizes to all the test bolts, obtaining the initial length of each test bolt before loading and the actual length of each test bolt after loading is finished, respectively calculating the actual rigidity coefficient of each test bolt according to the applied loading force and the corresponding initial length and actual length obtained respectively, finally calculating the stable rigidity coefficient according to the actual rigidity coefficient, and calculating the axial force of the bolt to be tested according to the stable rigidity coefficient. The measuring method provided by the application can quickly obtain the axial force of the bolt to be measured according to the deformation quantity of the bolt to be measured in use, is high in accuracy and small in error, can quickly and accurately measure the axial force of a plurality of bolts, and greatly improves the measuring efficiency on the basis of ensuring the measuring accuracy.
Description
Technical Field
The application relates to the technical field of mechanical parts, in particular to a method and a device for measuring axial force of a bolt.
Background
At present, in the manufacturing process of automobiles, bolt connection is the main connection mode of the whole automobile assembly, each automobile has about 3000 threaded connection points, a large number of safety and function related items are involved, the bolt tightening quality directly influences the corresponding effect of the automobile, even safety accidents are caused, therefore, the control of the bolt tightening quality is particularly important, and the most important factor influencing the bolt tightening quality is axial force.
In the related art, the most common method for measuring and controlling the axial force of a bolt is a torque wrench method, and the principle is to indirectly control the axial force according to the torque. However, since the torque coefficient is discrete due to the dispersion of the friction factors between the thread surfaces of the nut and the bolt and the contact surface of the nut and the connected member, in practical application, even under the conditions of ensuring the machining precision and ensuring good lubrication, the maximum measurement error of the axial force of the bolt with the same torque can reach about 30%.
Disclosure of Invention
The embodiment of the application provides a method and a device for measuring the axial force of a bolt, and aims to solve the problem that the bolt tightening quality is affected due to low measurement precision when the axial force of the bolt is monitored in the related technology.
In a first aspect, a method for measuring an axial force of a bolt is provided, which includes the steps of:
selecting at least two bolts as test bolts;
sequentially applying at least two loading forces with different sizes to all the test bolts respectively, and acquiring the initial length of each test bolt before loading and the actual length of each test bolt after loading;
respectively calculating the actual stiffness coefficient of each test bolt according to the applied loading force and the corresponding initial length and actual length which are respectively obtained;
and calculating to obtain a stable rigidity coefficient according to the actual rigidity coefficient, and calculating to obtain the axial force of the bolt to be tested according to the stable rigidity coefficient.
In some embodiments, after selecting at least two bolts as the test bolts, the steps further include: and respectively preprocessing the end faces of the selected test bolts.
In some embodiments, the step of pre-treating the selected end face of the test bolt comprises:
and polishing the top and the bottom of each test bolt to ensure that the parallelism error between the top and the bottom is not more than 0.02 degrees, the perpendicularity error between the top and the bottom and the bolt is not more than 0.02 degrees, and the roughness parameters of the top and the bottom are not more than 0.8.
In some embodiments, the step of sequentially applying at least two different loading forces to all the test bolts, and obtaining an initial length of each test bolt before loading and an actual length of each test bolt after loading is completed includes:
attaching an ultrasonic monitoring sheet to the top of the test bolt, and acquiring the initial length of the test bolt before loading by using the ultrasonic monitoring sheet;
and applying a loading force with a corresponding magnitude to the test bolt, and acquiring the actual length of the test bolt after loading by using the ultrasonic monitoring sheet after the loading is finished.
In some embodiments, the calculating according to the actual stiffness coefficient to obtain a stable stiffness coefficient, and then calculating according to the stable stiffness coefficient to obtain the axial force of the bolt to be tested, includes:
calculating the average value of all the actual rigidity coefficients to obtain the stable rigidity coefficient;
acquiring the actual deformation quantity of the bolt to be detected in use;
and calculating to obtain the axial force of the bolt to be measured according to the stable rigidity coefficient and the actual deformation quantity in use.
In some embodiments, when at least two loading forces with different magnitudes are sequentially applied to the test bolts, the magnitude of the loading force increases from small to large, and the number of times of applying the loading force to each test bolt ranges from 3 to 5.
In some embodiments, the application time of each of said loading forces is no less than 10 s.
In a second aspect, there is provided a measuring apparatus for measuring an actual rigidity coefficient of a bolt in the above measuring method, including:
the clamping unit comprises two symmetrically arranged clamping components, an accommodating cavity is formed between the two clamping components, the two clamping components can move oppositely or back to back so as to adjust the size of the accommodating cavity, and the accommodating cavity is used for accommodating test bolts with different sizes and nuts matched with the test bolts;
the loading unit is respectively connected with the two clamping assemblies and is used for driving the two clamping assemblies to move back and forth so as to apply corresponding loading force to the test bolt;
and the monitoring unit is used for monitoring the initial length of the test bolt before loading and the actual length of the test bolt after loading.
In some embodiments, each of the clamping assemblies is annular, and one end of the clamping assembly adjacent to the other clamping assembly is provided with an extending portion extending inwards, and the two extending portions are respectively used for abutting against a nut and a nut of the test bolt so as to retain the test bolt in the accommodating cavity.
In some embodiments, the monitoring unit is an ultrasonic monitoring patch.
The technical scheme who provides this application brings beneficial effect includes:
the embodiment of the application provides a method for measuring the axial force of a bolt, which comprises the steps of sequentially applying at least two loading forces with different sizes to all test bolts, acquiring the initial length of the test bolts before loading and the actual length after each loading, respectively calculating the actual rigidity coefficient of each test bolt according to the applied loading forces and the corresponding initial length and actual length which are acquired respectively, finally calculating the stable rigidity coefficient according to the actual rigidity coefficient, and then calculating the axial force of the bolt to be measured according to the stable rigidity coefficient, so that the method for measuring the axial force of the bolt can quickly obtain the axial force of the bolt to be measured by firstly determining the actual rigidity coefficient of the same batch of bolts and then according to the deformation quantity of the bolt to be measured during use, has high accuracy and small error, and can quickly and accurately measure the axial forces of a plurality of bolts, the efficiency of measurement has been improved greatly on the basis of guaranteeing measurement accuracy.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic view of a configuration of an assay device according to an embodiment of the present application;
FIG. 2 is a flowchart of a method for measuring an axial force of a bolt according to an embodiment of the present disclosure;
fig. 3 is a flowchart illustrating a method for measuring an axial force of a bolt according to an embodiment of the present disclosure when loading forces of different magnitudes are applied to the bolt;
fig. 4 is a flowchart of calculating the axial force of the bolt to be measured in the method for measuring the axial force of the bolt provided by the embodiment of the present application.
In the figure: 1-clamping unit, 10-clamping assembly, 100-extension part, 11-containing cavity, 2-loading unit, 20-loading assembly, 3-monitoring unit, 4-nut, 5-hydraulic device and 6-pressure sensor.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides a method for measuring the axial force of a bolt, which can solve the problem that the bolt tightening quality is affected due to low measurement precision when the axial force of the bolt is monitored in the related art.
Referring to fig. 1 and 2, the method for measuring the axial force of the bolt mainly comprises the following steps:
selecting at least two bolts as test bolts;
sequentially applying at least two loading forces with different sizes to all the test bolts respectively, and acquiring the initial length of each test bolt before loading and the actual length of each test bolt after loading;
respectively calculating the actual stiffness coefficient of each test bolt according to the applied loading force and the corresponding initial length and actual length which are respectively obtained;
and calculating to obtain a stable rigidity coefficient according to the actual rigidity coefficient, and calculating to obtain the axial force of the bolt to be tested according to the stable rigidity coefficient.
Specifically, the method for measuring the axial force of the bolt sequentially applies at least two loading forces with different sizes to all the test bolts, obtains the initial length of the test bolts before loading and the actual length after each loading, respectively calculates the actual stiffness coefficient of each test bolt according to the applied loading force and the corresponding initial length and actual length obtained respectively, finally calculates the stable stiffness coefficient according to the actual stiffness coefficient, and calculates the axial force of the bolt to be measured according to the stable stiffness coefficient, therefore, the method for measuring the axial force of the bolt can quickly obtain the axial force of the bolt to be measured by determining the actual stiffness coefficient of the same batch of bolts firstly and then according to the deformation quantity of the bolt to be measured during use, compared with the common torque pulling method for measuring and controlling the axial force of the bolt, the method does not need to control the axial force according to the torque, the method has the advantages that the problem of torque coefficient dispersion caused by the dispersion of friction factors between contact surfaces is solved, the measuring method is simple and easy to implement, interference factors are few, the accuracy of the whole measuring process is high, the result error is small, the axial force of a plurality of bolts can be rapidly and accurately measured, and the measuring efficiency is greatly improved on the basis of ensuring the measuring accuracy.
Further, after at least two bolts are selected as the test bolts, the method further comprises the following steps: and respectively preprocessing the end faces of the selected test bolts. Specifically, since the deformation amount of the test bolt under the loading action of different loading forces needs to be monitored, and the test bolt is fixed during loading, in order to prevent the structure such as burrs on the test bolt from affecting the accuracy of the measurement of the initial length of the test bolt and the actual length after loading is finished, when the loading test is performed by applying the loading force to the corresponding test bolt, the end face of the selected test bolt needs to be preprocessed first, so as to eliminate the measurement of the final axial force by the interference factors as much as possible.
Further, the step of pretreating the end face of the selected test bolt comprises: and polishing the top and the bottom of each test bolt to ensure that the parallelism error between the top and the bottom is not more than 0.02 degrees, the perpendicularity error between the top and the bottom and the bolt is not more than 0.02 degrees, and the roughness parameters of the top and the bottom are not more than 0.8.
Specifically, the top and the bottom of the test bolt are polished by a lathe and a grinding machine, the processing is smooth, the final axial force accuracy is guaranteed by the enclosing beam, the parallelism error between the top and the bottom after the processing is finished is not more than 0.02 degrees, the perpendicularity error between the top and the bottom and the bolt is not more than 0.02 degrees, and the roughness parameters of the top and the bottom are not more than 0.8 degrees. In addition, after polishing is finished, the surface of the test bolt is wiped, so that liquid which may pollute the test bolt, such as cutting fluid, cannot be used in the processing process, and in order to prevent the test bolt from being deformed due to excessive clamping force in the clamping and fixing process to influence the measurement result, a layer of soft metal, such as a copper sheet, can be coated on the clamping part of the test bolt, and the copper sheet can also be directly arranged on the clamping inner wall of the clamping device to avoid clamping the test bolt in the clamping and fixing process.
Further, referring to fig. 3, the step of sequentially applying at least two different loading forces to all the test bolts, and obtaining the initial length of each test bolt before loading and the actual length of each test bolt after loading is completed includes: attaching an ultrasonic monitoring sheet to the top of the test bolt, and acquiring the initial length of the test bolt before loading by using the ultrasonic monitoring sheet; and applying a loading force with a corresponding magnitude to the test bolt, and acquiring the actual length of the test bolt after loading by using the ultrasonic monitoring sheet after loading.
Further, referring to fig. 4, the step of calculating to obtain a stable stiffness coefficient according to the actual stiffness coefficient, and then calculating to obtain the axial force of the bolt to be tested according to the stable stiffness coefficient includes:
calculating the average value of all the actual rigidity coefficients to obtain the stable rigidity coefficient;
acquiring the actual deformation quantity of the bolt to be detected in use;
and calculating to obtain the axial force of the bolt to be measured according to the stable rigidity coefficient and the actual deformation quantity in use.
Further, when at least two loading forces with different sizes are sequentially applied to the test bolts, the size of the loading force is increased from small to large, and the value range of the number of times of applying the loading force to each test bolt is 3-5 times.
Specifically, in order to measure the accuracy of the data and improve the accuracy of the test as much as possible, 3 to 5 bolts are randomly extracted from the same batch of bolts as the test bolts, and the extracted bolts need to have no obvious defect so as to avoid the existence of other defects and the final number of testsThereby producing an effect. Assuming that 5 bolts were extracted as test bolts and A, B, C, D, E represents the 5 test bolts, the number of applied load forces was 3, and the load forces are represented as F in the order of magnitude from small to large 1 、F 2 、F 3 Therefore, after the test bolt a is applied with 3 different loading forces, three actual stiffness coefficients can be calculated, as shown in the following equations (1) - (3):
wherein x is 1 To apply a loading force F 1 The actual amount of deformation, x, measured at the time 2 To apply a loading force F 2 The actual amount of deformation, x, measured at the time 3 To apply a loading force F 3 And calculating three actual rigidity coefficients according to the obtained actual deformation quantity after three different loading forces are respectively and sequentially applied, and similarly, calculating the actual rigidity coefficients obtained after the different loading forces are respectively applied to the rest test bolts, as follows:
and after obtaining the actual rigidity coefficients of all the test bolts, calculating the average value of all the actual rigidity coefficients to obtain a stable rigidity coefficient, wherein the stable rigidity coefficient is determined as the rigidity coefficient of the batch of bolts. Since the test bolt is in the elastic deformation stage during the fastening loading, the deformation of the test bolt is proportional to the applied loading load, and this proportionality coefficient is the actual rigidity coefficient of the bolt, and the rigidity coefficient of the bolt is a constant during the use process, and for the bolts of the same batch, the rigidity coefficients can be considered to be consistent because the materials and the processing technology are basically the same. Therefore, in the measuring method, a plurality of bolts are randomly extracted to serve as test bolts, different loading forces are respectively applied to each test bolt, the current actual length of each test bolt is recorded after each loading, a plurality of actual rigidity coefficients of each test bolt are calculated respectively, the stable rigidity coefficient of the batch of bolts is obtained according to the actual rigidity coefficients, and when the batch of bolts are used, the axial force of the bolts can be quickly and accurately obtained by directly measuring the deformation quantity generated in the using process of the batch of bolts and combining the stable rigidity coefficient calculated in advance.
Furthermore, the application time of each loading force is not less than 10s, and the current actual length of the test bolt is obtained after the test bolt is stabilized.
The application also provides a measuring device for measuring the actual rigidity coefficient of the bolt in the measuring method, the measuring device mainly comprises a clamping unit 1, a loading unit 2 and a monitoring unit 3, wherein the clamping unit 1 comprises two clamping components 10 which are symmetrically arranged, a containing cavity 11 is formed between the two clamping components 10, the two clamping components 10 can move oppositely or back to adjust the size of the containing cavity 11, the containing cavity 11 is used for containing test bolts with different sizes and nuts 4 matched with the test bolts, the loading unit 2 is respectively connected with the two clamping components 10, the loading unit 2 is used for driving the two clamping components 10 to move back to apply corresponding loading force to the test bolts, the monitoring unit 3 is used for being arranged at the top of the test bolts, the monitoring unit 3 is used for monitoring the initial length of the test bolts before loading, and the actual length after loading.
Specifically, in the measuring device, since the containing cavity 11 is formed between the two clamping assemblies 10, and the two clamping assemblies 10 can move towards or away from each other, therefore, the size of the containing cavity 11 can be adjusted in the process of moving towards or away from each other, the containing cavity 11 is used for containing test bolts with different sizes and nuts 4 matched with the test bolts, the loading unit 2 is used for applying corresponding loading force to the test bolts by driving the two clamping assemblies 10, and the monitoring unit 3 is used for monitoring the initial length of the test bolt before loading and the actual length after loading, therefore, the housing 11 of the present measuring device can be adapted to test bolts having different sizes, for test bolts with different sizes, the bolts can be quickly fixed under the matching of the nuts 4, the operation is simple, and the measuring efficiency is high.
Furthermore, each of the clamping assemblies 10 is annular, and one end of the clamping assembly adjacent to the other clamping assembly 10 is provided with an extending portion 100 extending inwards, and the two extending portions 100 are respectively used for abutting against the nut and the nut 4 of the test bolt so as to retain the test bolt in the accommodating cavity 11. Specifically, when fixing the test bolt in a clamping manner, the test bolt sequentially passes through the two oppositely arranged clamping assemblies 10, after the nut at the top abuts against and is attached to the extending part 100 of the clamping assembly 10 above, the nut 4 is placed into the accommodating cavity 11 from the clamping assembly 10 below, and is rotatably connected with the tail part of the bolt until the nut 4 is selected into the bolt for a certain distance, and the two are stably connected.
Further, the loading unit 2 also includes two loading assemblies 20, each of the loading assemblies 20 is covered on one of the corresponding clamping assemblies 10, and an inner wall of each loading assembly 20 is fixedly connected with an outer wall of the corresponding clamping assembly 10, which may be in a threaded connection or in an integrally formed connection manner such as welding. The two loading assemblies 20 correspond to the two clamping assemblies 10 and are symmetrically and oppositely arranged along the vertical direction, and the loading assembly 20 positioned below is provided with an opening which is used for placing the nut 4 into the accommodating cavity 11 to be connected with the bottom of the bolt.
Further, the two symmetrically arranged loading assemblies 20 are respectively connected with a hydraulic device 5, and when loading is performed, the two loading assemblies 20 drive the two clamping assemblies 10 to move back and forth under the driving of the hydraulic device 5; a pressure sensor 6 is also provided between the two loading assemblies 20 for monitoring the magnitude and stability of the applied loading force.
Further, the monitoring unit 3 is an ultrasonic monitoring sheet, and only needs to be attached to the top of the test bolt.
The structure and implementation of the measuring device correspond to the steps of measuring the actual stiffness coefficient in the measuring method, and are not described one by one here.
In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.
It is noted that, in the present application, relational terms such as "first" and "second", and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The above description is merely exemplary of the present application and is presented to enable those skilled in the art to understand and practice the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A method for measuring the axial force of a bolt is characterized by comprising the following steps:
selecting at least two bolts as test bolts;
sequentially applying at least two loading forces with different sizes to all the test bolts respectively, and acquiring the initial length of each test bolt before loading and the actual length of each test bolt after loading;
respectively calculating the actual stiffness coefficient of each test bolt according to the applied loading force and the corresponding initial length and actual length which are respectively obtained;
and calculating to obtain a stable rigidity coefficient according to the actual rigidity coefficient, and calculating to obtain the axial force of the bolt to be tested according to the stable rigidity coefficient.
2. The method for measuring the axial force of the bolt according to claim 1, wherein after at least two bolts are selected as the test bolts, the method further comprises the steps of: and respectively preprocessing the end faces of the selected test bolts.
3. A method for determining the axial force of a bolt according to claim 2, wherein said pre-treating the end face of said selected test bolt comprises the steps of:
and polishing the top and the bottom of each test bolt to ensure that the parallelism error between the top and the bottom is not more than 0.02 degrees, the perpendicularity error between the top and the bottom and the bolt is not more than 0.02 degrees, and the roughness parameters of the top and the bottom are not more than 0.8.
4. The method for measuring the axial force of the bolt according to claim 1, wherein the steps of sequentially applying at least two different loading forces to all the test bolts respectively and obtaining the initial length of each test bolt before loading and the actual length of each test bolt after loading are performed comprise:
attaching an ultrasonic monitoring sheet to the top of the test bolt, and acquiring the initial length of the test bolt before loading by using the ultrasonic monitoring sheet;
and applying a loading force with a corresponding magnitude to the test bolt, and acquiring the actual length of the test bolt after loading by using the ultrasonic monitoring sheet after loading.
5. The method for measuring the axial force of the bolt according to claim 1, wherein the step of calculating the stable stiffness coefficient according to the actual stiffness coefficient and calculating the axial force of the bolt to be measured according to the stable stiffness coefficient comprises the following steps:
calculating the average value of all the actual rigidity coefficients to obtain the stable rigidity coefficient;
acquiring the actual deformation quantity of the bolt to be detected in use;
and calculating to obtain the axial force of the bolt to be tested according to the stable rigidity coefficient and the actual deformation quantity in use.
6. A method for measuring an axial force of a bolt according to claim 1, wherein: when at least two loading forces with different sizes are sequentially applied to the test bolts, the sizes of the loading forces are increased from small to large, and the value range of the times of applying the loading forces to each test bolt is 3-5 times.
7. A method for measuring an axial force of a bolt according to claim 1, wherein: the application time of each loading force is not less than 10 s.
8. An measuring apparatus for measuring an actual rigidity coefficient of a bolt in the measuring method according to claim 1, comprising:
the clamping unit (1) comprises two symmetrically arranged clamping assemblies (10), an accommodating cavity (11) is formed between the two clamping assemblies (10), the two clamping assemblies (10) can move oppositely or back to back so as to adjust the size of the accommodating cavity (11), and the accommodating cavity (11) is used for accommodating test bolts with different sizes and nuts (4) matched with the test bolts;
the loading unit (2) is respectively connected with the two clamping assemblies (10), and the loading unit (2) is used for driving the two clamping assemblies (10) to move back to back so as to apply corresponding loading force to the test bolt;
the monitoring unit (3) is used for being arranged at the top of the test bolt, and the monitoring unit (3) is used for monitoring the initial length of the test bolt before loading and the actual length of the test bolt after loading.
9. An assay device according to claim 8, wherein: each clamping assembly (10) is annular, one end adjacent to the other clamping assembly (10) is provided with an extending portion (100) extending inwards, and the two extending portions (100) are respectively used for abutting against and adhering to a nut and a nut (4) of the test bolt so as to keep the test bolt in the accommodating cavity (11).
10. An assay device according to claim 8, wherein: the monitoring unit (3) is an ultrasonic monitoring sheet.
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| CN202210494823.9A CN114964595A (en) | 2022-05-07 | 2022-05-07 | Method and device for measuring axial force of bolt |
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| CN202210494823.9A CN114964595A (en) | 2022-05-07 | 2022-05-07 | Method and device for measuring axial force of bolt |
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| CN113358266A (en) * | 2021-06-29 | 2021-09-07 | 神龙汽车有限公司 | Bolt assembling tension force testing method |
| CN215726662U (en) * | 2021-07-09 | 2022-02-01 | 天津众伟科技有限公司 | Numerical control machine tool cross beam bolt connection rigidity testing device |
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| CN107192494A (en) * | 2017-05-14 | 2017-09-22 | 北京工业大学 | A kind of device and method for the measure axial bolts relaxation for considering Contact characteristics |
| CN110514344A (en) * | 2019-07-18 | 2019-11-29 | 青海大学 | A kind of aero-engine bolt pretightening accuracy control method |
| CN111442869A (en) * | 2020-04-30 | 2020-07-24 | 北京理工大学 | Nonlinear ultrasonic detection method for axial stress of bolt |
| CN112179553A (en) * | 2020-09-09 | 2021-01-05 | 西南交通大学 | Method for ultrasonically and synchronously measuring axial force and shearing force of bolt |
| CN113358266A (en) * | 2021-06-29 | 2021-09-07 | 神龙汽车有限公司 | Bolt assembling tension force testing method |
| CN215726662U (en) * | 2021-07-09 | 2022-02-01 | 天津众伟科技有限公司 | Numerical control machine tool cross beam bolt connection rigidity testing device |
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