Method for processing pre-tightening force change curve, method and device for testing anti-loosening performance of thread

Abstract

The present invention provides a method for processing a pre-tightening force change curve, a method and device for testing the anti-loosening performance of a thread. Among them, the processing method includes: dividing the obtained pre-tightening force change curve into multiple change stages according to a preset interval; fitting the pre-tightening force change curve of each change stage, and obtaining the change slope corresponding to each change stage; according to a preset representation slope determination rule, obtaining a representation slope for determining the loosening condition of the thread connection structure to be tested. The technical solution of the present invention divides the obtained pre-tightening force change curve into change stages and fits the pre-tightening force change curve, obtains the change slope of each change stage, and then according to the preset representation slope determination rule, obtains a representation slope for characterizing the loosening condition of the thread connection structure, filling the technical gap that currently cannot accurately judge whether the thread connection structure is loose, and facilitating the realization of quantification and evaluation of the thread connection structure.

Description

Technical Field

[0001] The present invention relates to the technical field of testing, and particularly relates to a method for processing a pre-tightening force change curve, a method and a device for testing the anti-loosening performance of a thread. Background Art

[0002] Threaded connection structures are widely used in the fields of machinery, transportation, construction, etc. due to their advantages such as low cost, convenient disassembly and assembly, and large connection force. However, in actual use, due to the existence of various complex working conditions such as vibration and shock, the threaded connection structure is prone to loosening and failure. Therefore, engineers often adopt some anti-loosening measures to improve the anti-loosening performance, such as using anti-loosening fasteners. In order to facilitate making the best choice among different anti-loosening measures or optimizing the design and manufacturing process of specific anti-loosening fasteners, it is necessary to quantitatively evaluate the anti-loosening performance of the anti-loosening measures. However, there is currently no method for judging whether a threaded connection structure is loose on the market, nor any equipment for quantifying and evaluating the anti-loosening performance of a threaded connection structure, making it impossible to quantify and evaluate the anti-loosening performance of a threaded connection structure. Summary of the Invention

[0003] The technical objective to be achieved by the embodiments of the present invention is to provide a method for processing a pre-tightening force change curve, a method and a device for testing the anti-loosening performance of a thread, so as to solve the problem that there is currently no simple method for judging whether a threaded connection structure is loose, making it impossible to quantify and evaluate the anti-loosening performance of a threaded connection structure.

[0004] To solve the above technical problem, the embodiments of the present invention provide a method for processing a pre-tightening force change curve, including:

[0005] Dividing the pre-tightening force change curve of the threaded connection structure to be tested obtained in the test session of the vibration test into multiple change stages according to a preset interval;

[0006] Fitting the pre-tightening force change curve of each change stage respectively to obtain the change slope corresponding to each change stage;

[0007] Processing all the change slopes according to a preset characterization slope determination rule to obtain the characterization slope of the pre-tightening force change curve, where the characterization slope is used to determine the loosening condition of the threaded connection structure to be tested.

[0008] Specifically, for the above-mentioned processing method, the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative test time, representing the process of the pre-tightening force changing with the accumulation of the test time, or the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative number of vibration cycles, representing the process of the pre-tightening force changing with the accumulation of the number of vibration cycles.

[0009] Preferably, in the processing method described above, the characteristic slope refers to a target slope value that can represent the slowest decay rate of the pre-tightening force on the pre-tightening force change curve, or an equivalent transformation form of the target slope value.

[0010] Further, in the processing method described above, the preset characteristic slope determination rule includes: comparing all the obtained change slopes, and taking the change slope with the smallest absolute value as the characteristic slope; or, taking the absolute value of each of the obtained change slopes, and taking the smallest absolute value as the characteristic slope; or, performing normalization processing on each change slope to obtain the corresponding normalized slope, and taking the smallest normalized slope as the characteristic slope, where the normalized slope is the ratio of the absolute value of the change slope to the initial value of the pre-tightening force, and the initial value of the pre-tightening force refers to the value of the preset initial pre-tightening force in the test session.

[0011] Specifically, in the processing method described above, after determining the characteristic slope, the processing method further includes:

[0012] Comparing the characteristic slope with a preset slope threshold to obtain a comparison result;

[0013] When the comparison result is that the absolute value of the characteristic slope is greater than the slope threshold, it is determined that the threaded connection structure to be tested is loose;

[0014] When the comparison result is that the absolute value of the characteristic slope is less than the slope threshold, it is determined that the threaded connection structure to be tested is not loose.

[0015] Another preferred embodiment of the present invention further provides a processing device for a pre-tightening force change curve, including:

[0016] A first processing module, configured to divide the pre-tightening force change curve of the threaded connection structure to be tested obtained in the test session of the vibration test into multiple change stages according to a preset interval;

[0017] A second processing module, configured to respectively fit the pre-tightening force change curve of each change stage to obtain the change slope corresponding to each change stage;

[0018] A third processing module, configured to process all the change slopes according to a preset characteristic slope determination rule to obtain the characteristic slope of the pre-tightening force change curve, where the characteristic slope is used to determine the loosening condition of the threaded connection structure to be tested.

[0019] Specifically, the processing device described above further includes:

[0020] A fourth processing module, configured to compare the characteristic slope with a preset slope threshold to obtain a comparison result;

[0021] A fifth processing module, configured to determine that the threaded connection structure to be tested is loose when the comparison result indicates that the absolute value of the slope is greater than the slope threshold;

[0022] A sixth processing module, configured to determine that the threaded connection structure to be tested is not loose when the comparison result indicates that the absolute value of the slope is less than the slope threshold.

[0023] Yet another preferred embodiment of the present invention further provides a method for testing the anti-loosening performance of a threaded connection structure, including:

[0024] In the test sessions of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving force, and the preload force change curve of the threaded connection structure to be tested in each test session is obtained. Among them, the preset driving force is used as a characteristic variable to distinguish each test session. Each test session is driven according to a different preset driving force, and all test sessions have the same preset initial preload force;

[0025] According to the preload force change curve processing method, each preload force change curve is processed, and two target test sessions are determined;

[0026] The two preset driving forces corresponding to the two target test sessions are obtained as two target driving forces, and the two target driving forces are quantitatively processed according to the first preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the condition of the preset initial preload force.

[0027] Specifically, in the above-mentioned test method, the step of quantitatively processing the two target driving forces according to the first preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the condition of the preset initial preload force includes:

[0028] According to the two target driving forces, one of the target driving forces is used as the critical driving force; or a first preset operation is performed on the two target driving forces, and the obtained first operation result is used as the critical driving force;

[0029] According to the obtained critical driving force, the critical driving force is used as the characterization value; or, according to the corresponding relationship between the preset critical driving force and the characterization value, the characterization value is determined; or, a second preset operation is performed on the critical driving force, and the obtained second operation result is used as the characterization value.

[0030] Still another preferred embodiment of the present invention further provides a method for testing the anti-loosening performance of a threaded connection structure, including:

[0031] In the test session of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving force, and the preload force change curve of the threaded connection structure to be tested in each test session is obtained. Among them, the preset initial preload force is used as a characteristic variable to distinguish each test session. Each test session has a different preset initial preload force, and all test sessions are driven according to the same preset driving force;

[0032] According to the preload force change curve processing method, each preload force change curve is processed, and two target test sessions are determined;

[0033] The two preset initial preload forces corresponding to the two target test sessions are obtained as two target initial preload forces, and the two target initial preload forces are quantitatively processed according to the second preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force condition.

[0034] Specifically, in the above test method, the steps of quantitatively processing the two target initial preload forces according to the second preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force condition include:

[0035] According to the two target initial preload forces, one of the target initial preload forces is used as the critical initial preload force; or a third preset operation is performed on the two target initial preload forces, and the obtained third operation result is used as the critical initial preload force;

[0036] According to the obtained critical initial preload force, the critical initial preload force is used as the characterization value; or, the characterization value is determined according to the corresponding relationship between the preset critical initial preload force and the characterization value; or, a fourth preset operation is performed on the critical initial preload force, and the obtained fourth operation result is used as the characterization value.

[0037] Another preferred embodiment of the present invention further provides a test method for the anti-loosening performance of a threaded connection structure, including:

[0038] In the test session of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving displacement, and the preload force change curve of the threaded connection structure to be tested in each test session is obtained. Among them, the preset driving displacement is used as a characteristic variable to distinguish each test session. Each test session is driven according to a different preset driving displacement, and all test sessions have the same preset initial preload force;

[0039] According to the preload force change curve processing method, each preload force change curve is processed, and two target test sessions are determined;

[0040] Obtain two preset driving displacements corresponding to two target test sessions as two target driving displacements, and perform quantization processing on the two target driving displacements according to the third preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition.

[0041] Specifically, for the above-mentioned test method, the steps of performing quantization processing on the two target driving displacements according to the third preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition include:

[0042] According to the two target driving displacements, take one of the target driving displacements as the critical driving displacement; or perform a fifth preset operation on the two target driving displacements and take the obtained fifth operation result as the critical driving displacement;

[0043] According to the obtained critical driving displacement, take the critical driving displacement as the characterization value; or, determine the characterization value according to the corresponding relationship between the preset critical driving displacement and the characterization value; or perform a sixth preset operation on the critical driving displacement and take the obtained sixth operation result as the characterization value.

[0044] Another preferred embodiment of the present invention also provides a test method for the anti-loosening performance of a threaded connection structure, including;

[0045] In the test sessions of multiple vibration tests, periodically drive the threaded connection structure to be tested according to the preset driving displacement, and obtain the pre-tightening force change curve of the threaded connection structure to be tested in each test session, where the preset initial pre-tightening force is used as a characteristic variable for distinguishing each test session, each test session has a different preset initial pre-tightening force, and all test sessions are driven according to the same preset driving displacement;

[0046] According to the pre-tightening force change curve processing method, process each pre-tightening force change curve and determine two target test sessions;

[0047] Obtain two preset initial pre-tightening forces corresponding to the two target test sessions as two target initial pre-tightening forces, and perform quantization processing on the target initial pre-tightening force according to the fourth preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition.

[0048] Specifically, for the above-mentioned test method, the steps of performing quantization processing on the target initial pre-tightening force according to the fourth preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition include:

[0049] According to the two target initial pre-tightening forces, take one of the target initial pre-tightening forces as the critical initial pre-tightening force; or perform a seventh preset operation on the two target initial pre-tightening forces and take the obtained seventh operation result as the critical initial pre-tightening force;

[0050] According to the obtained critical initial pre-tightening force, use the critical initial pre-tightening force as the characterization value; alternatively, determine the characterization value according to the corresponding relationship between the preset critical initial pre-tightening force and the characterization value; or, perform an eighth preset operation on the critical initial pre-tightening force, and use the obtained eighth operation result as the characterization value.

[0051] Preferably, for the test method as described above, according to the pre-tightening force change curve processing method, processing each pre-tightening force change curve and determining the steps of two target test links include:

[0052] According to the pre-tightening force change curve processing method, process each pre-tightening force change curve to determine the loosening condition of the threaded connection structure to be tested in each test link;

[0053] When in two adjacent test links, one threaded connection structure to be tested becomes loose and the other threaded connection structure to be tested does not become loose, determine these two test links as the two target test links, where the two adjacent test links refer to: after sorting all the test links according to the magnitude of the characteristic variable, the two adjacent test links before and after.

[0054] Optionally, for the test method as described above, the test method further includes:

[0055] Sort all the test links according to the magnitude of the characteristic variable, and perform tests in sequence according to the obtained sorting to obtain the pre-tightening force change curve of the current test link;

[0056] Process the pre-tightening force change curve according to the pre-tightening force change curve processing method to obtain the loosening condition of the threaded connection structure in the current test link;

[0057] When it is determined that the loosening condition of the threaded connection structure in the current test link is the same as that in the previous test link or when the current test link is the first test link, proceed to the next test link;

[0058] When the loosening condition of the current test link is different from that of the previous test link, determine the current test link and the previous test link as the two target test links and stop the test.

[0059] Preferably, for the test method as described above, the steps of obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test link include:

[0060] Detect the pre-tightening force of the threaded connection structure to be tested;

[0061] When the pre-tightening force reaches the preset initial pre-tightening force of the current test link, send a test request message;

[0062] When receiving a test start signal, send the drive signal of the current test link to the drive mechanism, and start tracking and recording the monitored pre-tightening force to obtain data on the change of the pre-tightening force with the accumulation of test time, or obtain data on the change of the pre-tightening force with the accumulation of the number of vibration cycles. Among them, the drive signal carries information on the preset drive frequency and preset vibration cycle when controlling the drive mechanism for driving, and also carries information on the preset driving force or preset drive displacement;

[0063] According to the data on the change of the pre-tightening force with the accumulation of test time, or according to the data on the change of the pre-tightening force with the accumulation of the number of vibration cycles, obtain the pre-tightening force change curve of the current test link.

[0064] Specifically, for the test method described above, the pre-tightening force change curve processing method is the pre-tightening force change curve processing method described above.

[0065] Another preferred embodiment of the present invention further provides a test device for the anti-loosening performance of a threaded connection structure, including:

[0066] A support plate, a connecting plate, a drive mechanism, and a first pressure sensor;

[0067] Among them, the connecting plate is placed on the support plate and fixedly connected through the threaded connection structure to be tested;

[0068] The first pressure sensor is arranged between the threaded connection structure and the support plate or the connecting plate, and is used to monitor the pre-tightening force of the threaded connection structure;

[0069] The drive mechanism is connected to one end of the connecting plate, and the drive mechanism is used to periodically apply a driving force in the test direction to the connecting plate, and the test direction is perpendicular to the extension direction of the helix of the threaded connection structure.

[0070] Specifically, for the test device described above, the threaded connection structure includes: an internal threaded part and an external threaded part;

[0071] Among them, the external threaded part includes: a head provided with a stress structure and a threaded part provided with an external thread;

[0072] Installation holes for the external threaded part to pass through are provided on both the support plate and the connecting plate. When the external threaded part passes through the support plate and the connecting plate, the first pressure sensor is arranged between the support plate and the head of the external threaded part or the internal threaded part.

[0073] Further, for the test device described above, a groove is provided on the side of the support plate away from the connecting plate, the first pressure sensor is arranged in the groove, and the installation hole communicates with the groove.

[0074] Preferably, for the test device described above, a second pressure sensor is arranged between the connecting plate and the drive mechanism, and the second pressure sensor is also communicatively connected to the drive mechanism.

[0075] Specifically, the testing device described above further includes: a displacement sensor, which is communicatively connected to the driving mechanism, and the displacement sensor is used to monitor the driving displacement of the connecting plate.

[0076] Compared with the prior art, the pre-tightening force change curve processing method, the thread loosening prevention performance testing method and device provided by the embodiments of the present invention have at least the following beneficial effects:

[0077] By dividing the obtained pre-tightening force change curve of the threaded connection structure to be tested in the test link of the vibration test and fitting the pre-tightening force change curve of each change stage, the change slope corresponding to each change stage is obtained. Furthermore, according to the preset characterization slope determination rule, the characterization slope for characterizing the loosening condition of the threaded connection structure to be tested can be obtained from all the obtained change slopes. Whether the threaded connection structure to be tested is loosened can be simply determined through this characterization slope, filling the technical gap that currently cannot accurately judge whether the threaded connection structure is loosened, and facilitating the realization of quantification and evaluation of the threaded connection structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is one of the schematic flowcharts of a pre-tightening force change curve processing method of the present invention;

[0079] Figure 2 It is a schematic diagram of a pre-tightening force change curve;

[0080] Figure 3 It is a schematic diagram of a change curve of a pre-tightening force change slope;

[0081] Figure 4 It is the second of the schematic flowcharts of a pre-tightening force change curve processing method of the present invention;

[0082] Figure 5 It is a schematic structural diagram of a processing device for a pre-tightening force change curve of the present invention;

[0083] Figure 6 It is one of the schematic flowcharts of a testing method for the loosening prevention performance of a threaded connection structure;

[0084] Figure 7 It is the second of the schematic flowcharts of a testing method for the loosening prevention performance of a threaded connection structure;

[0085] Figure 8 It is the third of the schematic flowcharts of a testing method for the loosening prevention performance of a threaded connection structure;

[0086] Figure 9 It is the fourth of the schematic flowcharts of a testing method for the loosening prevention performance of a threaded connection structure;

[0087] Figure 10 It is the fifth flow schematic diagram of a test method for the anti-loosening performance of a threaded connection structure;

[0088] Figure 11 It is the sixth flow schematic diagram of a test method for the anti-loosening performance of a threaded connection structure;

[0089] Figure 12 It is the seventh flow schematic diagram of a test method for the anti-loosening performance of a threaded connection structure;

[0090] Figure 13 It is the structural schematic diagram of a test device for the anti-loosening performance of a threaded connection structure. Specific embodiments

[0091] To make the technical problems, technical solutions, and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. In the following description, specific details such as specific configurations and components are provided only to help a comprehensive understanding of the embodiments of the present invention. Therefore, those skilled in the art should clearly understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. In addition, descriptions of known functions and configurations are omitted for clarity and conciseness.

[0092] It should be understood that the term "one embodiment" or "an embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, the appearances of "in one embodiment" or "in an embodiment" throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0093] In various embodiments of the present invention, it should be understood that the magnitudes of the serial numbers of the following processes do not mean the order of execution is prior or subsequent, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0094] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0095] In the embodiments provided in the present application, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0096] See Figure 1 , a preferred embodiment of the present invention provides a method for processing a pre-tightening force change curve, including:

[0097] Step S101, divide the pre-tightening force change curve of the threaded connection structure to be tested obtained in the test session of the vibration test into multiple change stages according to a preset interval;

[0098] Step S102, respectively fit the pre-tightening force change curve of each change stage to obtain the change slope corresponding to each change stage;

[0099] Step S103, process all the change slopes according to a preset characterization slope determination rule to obtain the characterization slope of the pre-tightening force change curve, wherein the characterization slope is used to determine the loosening condition of the threaded connection structure to be tested.

[0100] In a specific embodiment of the present invention, the obtained pre-tightening force change curve is preferably the pre-tightening force change curve of the threaded connection structure under a preset force condition simulated by a test device for the anti-loosening performance of the threaded connection structure within a period of time. After obtaining the pre-tightening force change curve, the pre-tightening force change curve will be divided into multiple change stages according to a preset interval, and the pre-tightening force change curve of each change stage will be fitted to obtain the change slope corresponding to each change stage, wherein the change slope is used to represent the change speed or change rate of the pre-tightening force in this change stage. Furthermore, according to the preset characterization slope determination rule, all the obtained change slopes can be processed, and then the characterization slope for characterizing the loosening condition of the threaded connection structure to be tested can be obtained. Whether the threaded connection structure to be tested is loosened can be determined through this characterization slope, filling the technical gap that currently cannot accurately judge whether the threaded connection structure is loosened through the pre-tightening force change curve, and facilitating the quantification and evaluation of the anti-loosening performance of the threaded connection structure.

[0101] Preferably, the loosening described in the embodiments of the present invention refers to rotational loosening, which means that the threaded connection structure has undergone a rigid rotation that causes the pre-tightening force to decline; preferably, the anti-loosening performance described in the embodiments of the present invention refers to the ability to prevent rotational loosening.

[0102] Preferably, linear fitting is preferably used when fitting the pre-tightening force change curve, especially first-order linear fitting, in order to facilitate obtaining the change slope of the change stage. Optionally, those skilled in the art using other fitting methods such as the least squares curve fitting method for fitting to obtain the change slope of this change stage should also fall within the protection scope of the present invention.

[0103] See Figure 2Taking the change process of the pre-tightening force accumulated with the number of vibration cycles as an example, the shown pre-tightening force change curve can intuitively show that there are three major stages in the pre-tightening force change curve. Among them, in the first stage at the beginning, under the influence of plastic deformation factors, the pre-tightening force change curve will decline rapidly in a non-linear manner. In the second stage, due to the end of plastic deformation, at this time, the pre-tightening force change curve approximately declines linearly under the influence of the rotational loosening between the internal and external threads. In the third stage, due to the long stress time of the threaded connection structure, cracks begin to appear in the threaded connection structure due to fatigue, resulting in an accelerated decline rate of the pre-tightening force until sudden fracture. Thus, it can be seen that the key to judging whether the threaded connection structure is loose lies in the decline rate in the second stage, and the data in the rapidly declining stages, namely the first stage and the third stage, has a poor correlation with the anti-loosening performance of the threaded connection structure.

[0104] It should be noted here that the described change stages are obtained by further dividing the above three major stages according to the preset interval, rather than referring to the three major stages themselves. Since the key to judging whether the threaded connection structure is loose lies in the decline rate in the second stage, the first stage and the third stage can be partially or completely ignored when dividing the change stages and obtaining the change slope, and only the second stage is divided into change stages and the change slope is obtained.

[0105] Optionally, after obtaining the change slope corresponding to each change stage, a curve reflecting the evolution process of the pre-tightening force decline rate can be drawn, as Figure 3 shown. Among them, the vertical axis represents the value of the change slope, and the horizontal axis represents the cumulative number of vibration cycles, so as to facilitate technicians to more intuitively understand the decline of the pre-tightening force. It should be noted here that the vertical axis can also be in other forms, such as the absolute value of the change slope, or the ratio of the absolute value of the change slope to the initial value of the pre-tightening force, etc.; the horizontal axis can also be in other forms, such as the cumulative test time.

[0106] Specifically, for the above-mentioned processing method, the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative test time, representing the process of the pre-tightening force changing with the accumulation of the test time, or the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative number of vibration cycles, representing the process of the pre-tightening force changing with the accumulation of the number of vibration cycles.

[0107] In a specific embodiment of the present invention, according to the different processing methods adopted by technicians during vibration tests, the preload force change curve when the preload force changes following the independent variable can be determined based on different independent variables. For example, when the independent variable is time, the obtained preload force change curve is the relationship curve between the preload force and the cumulative test time, which is used to represent the process of the preload force changing with the accumulation of the test time. At this time, the preset interval is the preset time span, which is beneficial to improving the division efficiency; when the independent variable is the vibration cycle, the obtained preload force change curve is the relationship curve between the preload force and the cumulative number of vibration cycles, which is used to represent the process of the preload force changing with the accumulation of the number of vibration cycles. At this time, the preset interval is the preset number of vibration cycles, which can ensure that the data in the obtained change stage are all data of complete cycles.

[0108] Preferably, when determining the preset interval, when the preload force change curve is the relationship curve between the preload force and the cumulative test time, the product of a specific integer number of vibration cycles and the unit cycle time is selected as the preset interval; when the preload force change curve is the relationship curve between the preload force and the cumulative number of vibration cycles, a specific integer number of vibration cycles is selected as the preset interval. This is to facilitate the division of the change stage and ensure the rationality of the preload force data in each divided change stage. Optionally, those skilled in the art can make a selective setting according to the actual situation or habit, while ensuring the normal progress of the division of the change stage and meeting the personalized needs of technicians. It should be noted that the above preset interval is the time span or vibration cycle span or other equivalent forms preset by technicians according to the actual situation.

[0109] Preferably, in the above processing method, the representative slope refers to a target slope value that can represent the slowest decay speed of the preload force on the preload force change curve, or an equivalent conversion form of the target slope value.

[0110] It should also be noted that the slopes corresponding to different positions on the entire preload force change curve are usually different, which means that the decay speed of the preload force is usually not constant and changes with the continuation of vibration. Even in the above second stage, its preload force decay speed may not be completely constant. Therefore, in the embodiment of the present invention, a target slope value that can represent the slowest decay speed of the preload force on the entire preload force change curve, or an equivalent conversion form of the target slope value, is used as the representative slope, so that the representative slope can represent the best situation of the preload force decay on the preload force change curve. Therefore, the representative slope can be used to determine the loosening condition of the to-be-tested threaded connection structure, and thus facilitate the judgment of the loosening condition of the to-be-tested threaded connection structure to obtain a judgment result. Among them, the above equivalent conversion form is a value obtained by technicians converting the target slope value according to a preset equivalent conversion method, including but not limited to taking the absolute value or obtaining a value through a certain operation.

[0111] Furthermore, in the processing method as described above, the preset characterization slope determination rule includes: comparing all the obtained change slopes, and taking the change slope with the smallest absolute value as the characterization slope; or, taking the absolute values ​​of all the obtained change slopes respectively, and taking the smallest absolute value as the characterization slope; or, normalizing each change slope to obtain the corresponding normalized slope, and taking the smallest normalized slope as the characterization slope, wherein the normalized slope is the ratio of the absolute value of the change slope to the initial value of the preload force, and the initial value of the preload force refers to the value of the preset initial preload force of the test link.

[0112] In a specific embodiment of the present invention, since the value of the changing slope can be used to characterize the decay rate of the preload, the closer the value of the changing slope is to zero, it usually indicates that the preload in this changing stage decays more slowly, that is, the changing stage can better represent the slowest decay rate of the preload on the entire preload change curve (that is, the best case on the preload change curve). Therefore, based on all the changing slopes, a changing slope relatively close to zero (that is, the target slope) or some equivalent transformation form thereof can be determined as the characterization slope; that is, the preset characterization slope determination rule is used to determine a changing slope relatively close to zero, and use the changing slope or some equivalent transformation form thereof as the characterization slope.

[0113] Specifically, the present invention provides some specific embodiments, for example: all the change slopes are compared and the change slope with the smallest absolute value is used as the characterization slope, in which case the characterization slope is positive, negative or zero; or, the absolute values ​​of all the obtained change slopes are taken respectively, and the smallest absolute value is used as the characterization slope, in which case the characterization slope is a non-negative value; or, each change slope is normalized to obtain the corresponding normalized slope, and the smallest normalized slope is used as the characterization slope, in which case the characterization slope is a non-negative value. Optionally, a technician in this field can determine the average value of all change slopes within a preset value range as the characterization slope on this basis, wherein the absolute value of any value in the preset value range is less than a preset value; or, all the change slopes are sorted in order from small to large according to the absolute value, and the average value of the preset number of change slopes at the top of the sort is selected as the characterization slope, or the value or average value of the change slope at a preset position is selected as the characterization slope.

[0114] See also Figure 4 Specifically, in the processing method described above, after determining the characterization slope, the processing method further includes:

[0115] Step S401, comparing the characterization slope with a preset slope threshold to obtain a comparison result;

[0116] Step S402: When the absolute value of the represented slope is greater than the slope threshold, it is determined that the threaded connection structure to be tested is loose;

[0117] Step S403: When the absolute value of the represented slope is less than the slope threshold, it is determined that the threaded connection structure to be tested is not loose.

[0118] In a specific embodiment of the present invention, after determining the represented slope, when judging whether the threaded connection structure to be tested is loose, the represented slope will be compared with a preset slope threshold. When the absolute value of the represented slope is greater than the preset slope, it indicates that during the vibration test, the pre-tightening force decay rate of the threaded connection structure to be tested is relatively fast, exceeding the allowable range, resulting in obvious loosening of the threaded connection structure to be tested. At this time, it can be determined that the loosening condition of the threaded connection structure to be tested is loose; when the absolute value of the represented slope is less than the slope threshold, it indicates that during the vibration test, the pre-tightening force decay rate of the threaded connection structure to be tested is relatively slow or has not decayed, and it is still within the allowable range, so it can be determined that the loosening condition of the threaded connection structure to be tested is not loose. It should be noted that when the absolute value of the represented slope is equal to the slope threshold, at this time the threaded connection structure is in a critical state of about to loosen. Technicians can determine the loosening condition of the threaded connection structure to be tested as loose or not loose according to the actual situation. In the present invention, it is preferably determined that the loosening condition of the threaded connection structure to be tested is not loose when the absolute value of the represented slope is equal to the slope threshold.

[0119] Here it should be noted that the processing methods described in Step S401, Step S402, and Step S403 may also have other equivalent forms. For example, when the represented slope itself is positive, there is no need to take the absolute value operation on it; for another example, when both the represented slope and the slope threshold are negative, the represented slope being less than the slope threshold means that the threaded connection structure to be tested is loose, and vice versa means it is not loose. The essence of the above-mentioned situations is equivalent to the processing methods described in Step S401, Step S402, and Step S403, that is: taking the slope threshold as a reference, when the pre-tightening force decay degree represented by the represented slope is more serious than the pre-tightening force decay degree represented by the slope threshold, it is determined that the threaded connection structure to be tested is loose, and vice versa it is determined that it is not loose. As long as all the processing methods conform to this principle, regardless of their specific implementation forms, they should be included in the protection scope of the present invention.

[0120] See Figure 5 , another preferred embodiment of the present invention also provides a processing device for the pre-tightening force change curve, including:

[0121] The first processing module 51 is configured to divide the pre-tightening force change curve of the to-be-tested threaded connection structure obtained in the test session of the vibration test into multiple change stages according to a preset interval;

[0122] The second processing module 52 is configured to respectively fit the pre-tightening force change curve of each change stage to obtain the change slope corresponding to each change stage;

[0123] The third processing module 53 is configured to process all the change slopes according to a preset characterization slope determination rule to obtain the characterization slope of the pre-tightening force change curve, wherein the characterization slope is used to determine the loosening condition of the to-be-tested threaded connection structure.

[0124] Specifically, the processing device as described above further includes:

[0125] The fourth processing module is configured to compare the characterization slope with a preset slope threshold to obtain a comparison result;

[0126] The fifth processing module is configured to determine that the to-be-tested threaded connection structure is loosened when the comparison result shows that the absolute value of the characterization slope is greater than the slope threshold;

[0127] The sixth processing module is configured to determine that the to-be-tested threaded connection structure is not loosened when the comparison result shows that the absolute value of the characterization slope is less than the slope threshold.

[0128] The embodiment of the processing device of the present invention is a processing device corresponding to the embodiment of the above processing method. All the implementation means in the embodiment of the above processing method are applicable to the embodiment of this processing device and can also achieve the same technical effect. The modules in the above processing device can be computer programs for realizing specific functions.

[0129] See Figure 6 , and yet another preferred embodiment of the present invention further provides a method for testing the anti-loosening performance of a threaded connection structure, including:

[0130] Step S601, in the test sessions of multiple vibration tests, periodically drive the to-be-tested threaded connection structure according to a preset driving force, and obtain the pre-tightening force change curve of the to-be-tested threaded connection structure in each test session, wherein the preset driving force is used as a characteristic variable for distinguishing each test session, each test session is driven according to a different preset driving force, and all the test sessions have the same preset initial pre-tightening force;

[0131] Step S602, process each pre-tightening force change curve according to the pre-tightening force change curve processing method, and determine two target test sessions;

[0132] Step S603: Obtain two preset driving forces corresponding to two target test links as two target driving forces, and perform quantization processing on the two target driving forces according to a first preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition.

[0133] In a preferred embodiment of the present invention, when testing the anti-loosening performance of a threaded connection structure, multiple test links are carried out in a vibration test, and the same preset initial pre-tightening force is applied to the threaded connection structure to be tested in each test link, and the threaded connection structure to be tested is periodically driven according to different preset driving forces. Since the preset driving forces of each test link are different, the preset driving force can be used as a characteristic variable to distinguish each test link. After obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test link, according to the above-mentioned pre-tightening force change curve processing method, each pre-tightening force change curve is processed separately, and two target test links near the critical state between loosening and non-loosening of the threaded connection structure to be tested can be determined, that is, the threaded connection structure to be tested in one target test link loosens, and the threaded connection structure to be tested in the other target test link does not loosen; take the preset driving forces in the two target test links as target driving forces, and perform quantization processing on the two target driving forces according to a first preset quantization rule obtained or set in advance, and a characterization value of the anti-loosening performance of the threaded connection structure of the same type as the threaded connection structure to be tested under the preset initial pre-tightening force condition can be obtained. By quantifying the anti-loosening performance of the threaded connection structure, quantitative measurement and evaluation of the threaded connection structure can be realized. Furthermore, when a user selects a threaded connection structure, a suitable threaded connection structure can be selected according to the quantified value or it can be evaluated whether the currently selected threaded connection structure is a suitable combination. At the same time, it is also convenient for the user to compare the anti-loosening performances of two different types or specifications of threaded connection structures.

[0134] It should be noted that the driving force is a periodic force. For convenience, an effective value or a maximum value can be selected to characterize the driving force.

[0135] Specifically, for the above-mentioned test method, the steps of performing quantization processing on the two target driving forces according to the first preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition include:

[0136] According to the two target driving forces, take one of the target driving forces as the critical driving force; or perform a first preset operation on the two target driving forces, and take the obtained first operation result as the critical driving force;

[0137] According to the obtained critical driving force, the critical driving force is used as the characterization value; alternatively, the characterization value is determined according to the preset correspondence between the critical driving force and the characterization value; or, the critical driving force is subjected to a second preset operation, and the obtained second operation result is used as the characterization value.

[0138] In a specific embodiment of the present invention, the first preset quantization rule is used to quantify two target driving forces of a threaded connection structure with the same preset initial pre-tightening force. First, the critical driving force when the threaded connection structure is in a critical state is determined according to the two target driving forces, that is, the driving force corresponding to the state between the loosening and non-loosening of the threaded connection structure. Then, the critical driving force is quantified to obtain the characterization value of the anti-loosening performance of the threaded connection structure.

[0139] Among them, when determining the critical driving force when the threaded connection structure is in a critical state according to the two target driving forces, one of the two target driving forces can be selected as the critical driving force. In a preferred embodiment of the present invention, the target driving force when the threaded connection structure does not loosen is selected as the critical driving force, which is beneficial to ensure that when the user selects the threaded connection structure according to the critical driving force, the requirement for anti-loosening performance can be met.

[0140] In addition, when determining the critical driving force when the threaded connection structure is in a critical state according to the two target driving forces, a first preset operation can also be performed on the two target driving forces, and the obtained first operation result is used as the critical driving force. Among them, the first preset operation includes but is not limited to: taking an average value operation; or increasing or decreasing one of the target driving forces by a fixed value, and the fixed value is less than the difference between the two target driving forces; or using other operations for obtaining a value between the two target driving forces.

[0141] When quantifying the critical driving force, the critical driving force can be directly used as the characterization value of the anti-loosening performance; or, a correspondence between the critical driving force and the characterization value is established in advance. For example, a critical driving force within a value range corresponds to a characterization value, where the characterization value can be simplified to an anti-loosening ability level; or, a second preset operation is performed on the critical driving force, and the obtained second operation result is used as the characterization value. For example, a functional operation relationship is formed between the critical driving force and the characterization value through at least one calibrated constant, etc.

[0142] See Figure 7 Furthermore, a preferred embodiment of the present invention also provides a test method for the anti-loosening performance of a threaded connection structure, including:

[0143] Step S701, in the test session of multiple vibration tests, periodically drive the threaded connection structure to be tested according to a preset driving force, and obtain the pre-tightening force change curve of the threaded connection structure to be tested in each test session, where the preset initial pre-tightening force is used as a characteristic variable to distinguish each test session, each test session has a different preset initial pre-tightening force, and all test sessions are driven according to the same preset driving force;

[0144] Step S702, according to the pre-tightening force change curve processing method, process each pre-tightening force change curve and determine two target test sessions;

[0145] Step S703, obtain the two preset initial pre-tightening forces corresponding to the two target test sessions as two target initial pre-tightening forces, and perform quantization processing on the two target initial pre-tightening forces according to the second preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force condition.

[0146] In another preferred embodiment of the present invention, when testing the anti-loosening performance of the threaded connection structure, multiple test sessions will be carried out in the vibration test, and different preset initial pre-tightening forces will be applied to the threaded connection structure to be tested in each test session, and the threaded connection structure to be tested will be periodically driven according to the same preset driving force. Since the preset initial pre-tightening force of each test session is different, the preset initial pre-tightening force can be used as a characteristic variable to distinguish each test session. After obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test session, according to the above-mentioned pre-tightening force change curve processing method, each pre-tightening force change curve is processed separately, and two target test sessions near the critical state between loosening and non-loosening of the threaded connection structure to be tested can be determined, that is, the threaded connection structure to be tested in one target test session is loosened, and the threaded connection structure to be tested in the other target test session is not loosened; the preset initial pre-tightening forces in the two target test sessions are used as target initial pre-tightening forces, and quantization processing is performed on the two target initial pre-tightening forces according to the second preset quantization rule obtained or set in advance, and the characterization value of the anti-loosening performance of the threaded connection structure of the same type as the threaded connection structure to be tested under the preset driving force condition can be obtained. By quantifying the anti-loosening performance of the threaded connection structure, the quantitative measurement and evaluation of the threaded connection structure can be realized. Furthermore, when the user selects a threaded connection structure, the user can select a suitable threaded connection structure according to the quantified value or evaluate whether the currently selected threaded connection structure is a suitable combination. At the same time, it is also convenient for the user to compare the anti-loosening performance of two different types or specifications of threaded connection structures.

[0147] It should be noted that the driving force is a periodic force. For convenience, an effective value or a maximum value can be selected to characterize the driving force.

[0148] Specifically, for the testing method described above, the steps of quantifying two target initial pre-tightening forces according to the second preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force conditions include:

[0149] Based on the two target initial pre-tightening forces, one of the target initial pre-tightening forces is used as the critical initial pre-tightening force; or a third preset operation is performed on the two target initial pre-tightening forces, and the obtained third operation result is used as the critical initial pre-tightening force;

[0150] Based on the obtained critical initial pre-tightening force, the critical initial pre-tightening force is used as the characterization value; or, the characterization value is determined according to the corresponding relationship between the preset critical initial pre-tightening force and the characterization value; or, a fourth preset operation is performed on the critical initial pre-tightening force, and the obtained fourth operation result is used as the characterization value.

[0151] In a specific embodiment of the present invention, the second preset quantization rule is used to quantify two target initial pre-tightening forces of a threaded connection structure with the same preset driving force. First, the critical initial pre-tightening force when the threaded connection structure is in a critical state is determined according to the two target initial pre-tightening forces, that is, the initial pre-tightening force corresponding to the state between the loosening and non-loosening of the threaded connection structure. Then, the critical initial pre-tightening force is quantified to obtain a characterization value of the anti-loosening performance of the threaded connection structure;

[0152] Among them, when determining the critical initial pre-tightening force when the threaded connection structure is in a critical state according to the two target initial pre-tightening forces, one of the two target initial pre-tightening forces can be selected as the critical initial pre-tightening force. In a preferred embodiment of the present invention, the target initial pre-tightening force when the threaded connection structure does not loosen is selected as the critical initial pre-tightening force, which is beneficial to ensuring that when the user selects the threaded connection structure according to the critical initial pre-tightening force, the requirement for anti-loosening performance can be met;

[0153] In addition, when determining the critical initial pre-tightening force when the threaded connection structure is in a critical state according to the two target initial pre-tightening forces, a third preset operation can also be performed on the two target initial pre-tightening forces, and the obtained third operation result is used as the critical initial pre-tightening force. Among them, the third preset operation includes but is not limited to: taking an average value operation; or increasing or decreasing one of the target initial pre-tightening forces by a fixed value, and the fixed value is less than the difference between the two target initial pre-tightening forces; or using other operations for obtaining a value between the two target initial pre-tightening forces.

[0154] When quantifying the critical initial pre-tightening force, the critical initial pre-tightening force can be directly used as the characterization value of the anti-loosening performance; or, a corresponding relationship is established in advance between the critical initial pre-tightening force and the characterization value. For example, a critical initial pre-tightening force within a certain value range corresponds to a characterization value, where the characterization value can be simplified to the anti-loosening ability level; or, a fourth preset operation is performed on the critical initial pre-tightening force, and the obtained fourth operation result is used as the characterization value. For example, a functional operation relationship is formed between the critical initial pre-tightening force and the characterization value through at least one calibrated constant, etc.

[0155] See Figure 8 , another preferred embodiment of the present invention further provides a test method for the anti-loosening performance of a threaded connection structure, including:

[0156] Step S801, in the test links of multiple vibration tests, periodically drive the threaded connection structure to be tested according to a preset driving displacement, and obtain the pre-tightening force change curve of the threaded connection structure to be tested in each test link. Among them, the preset driving displacement is used as the characteristic variable for distinguishing each test link. Each test link is driven according to a different preset driving displacement, and all test links have the same preset initial pre-tightening force;

[0157] Step S802, process each pre-tightening force change curve according to the pre-tightening force change curve processing method, and determine two target test links;

[0158] Step S803, obtain two preset driving displacements corresponding to the two target test links as two target driving displacements, and perform quantization processing on the two target driving displacements according to the third preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the condition of the preset initial pre-tightening force.

[0159] In a preferred embodiment of the present invention, when testing the anti-loosening performance of a threaded connection structure, multiple test steps are carried out in a vibration test. In each test step, the same preset initial pre-tightening force is applied to the threaded connection structure to be tested, and the threaded connection structure to be tested is periodically driven according to different preset driving displacements. Since the preset driving displacements in each test step are different, the preset driving displacement can be used as a characteristic variable to distinguish each test step. After obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test step, according to the above-mentioned pre-tightening force change curve processing method, each pre-tightening force change curve is processed separately, and two target test steps near the critical state between loosening and non-loosening of the threaded connection structure to be tested can be determined, that is, the threaded connection structure to be tested loosens in one target test step, and the threaded connection structure to be tested does not loosen in the other target test step; the preset driving displacements in the two target test steps are used as the target driving displacements, and the two target driving displacements are quantitatively processed according to a third preset quantization rule obtained or set in advance, and the characterization value of the anti-loosening performance of the threaded connection structure of the same type as the threaded connection structure to be tested under the condition of the preset initial pre-tightening force can be obtained. By quantitatively processing the anti-loosening performance of the threaded connection structure, the quantitative measurement and evaluation of the threaded connection structure can be realized. Furthermore, when a user selects a threaded connection structure, the user can select a suitable threaded connection structure according to the quantified value or evaluate whether the currently selected threaded connection structure is a suitable combination. At the same time, it is also convenient for the user to compare the anti-loosening performances of two threaded connection structures of different types or specifications.

[0160] It should be noted that the driving displacement is periodic. For convenience, a valid value or a maximum value can be selected to represent the driving displacement.

[0161] Specifically, for the above-mentioned test method, the steps of quantitatively processing the two target driving displacements according to the third preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the condition of the preset initial pre-tightening force include:

[0162] According to the two target driving displacements, one of the target driving displacements is used as the critical driving displacement; or a fifth preset operation is performed on the two target driving displacements, and the obtained fifth operation result is used as the critical driving displacement;

[0163] According to the obtained critical driving displacement, the critical driving displacement is used as the characterization value; or, the characterization value is determined according to the corresponding relationship between the preset critical driving displacement and the characterization value; or, a sixth preset operation is performed on the critical driving displacement, and the obtained sixth operation result is used as the characterization value.

[0164] In a specific embodiment of the present invention, the first preset quantization rule is used to quantify two target driving displacements of a threaded connection structure having the same preset initial pre-tightening force. First, the critical driving displacement when the threaded connection structure is in a critical state is determined according to the two target driving displacements, that is, the driving displacement corresponding to the state between the loosening and non-loosening of the threaded connection structure. Then, the critical driving displacement is quantified to obtain a characterization value of the anti-loosening performance of the threaded connection structure;

[0165] Among them, when determining the critical driving displacement when the threaded connection structure is in a critical state according to the two target driving displacements, one of the two target driving displacements can be selected as the critical driving displacement. In a preferred embodiment of the present invention, the target driving displacement when the threaded connection structure does not loosen is selected as the critical driving displacement, which is beneficial to ensuring that when the user selects the threaded connection structure according to the critical driving displacement, the requirement for anti-loosening performance can be met;

[0166] In addition, when determining the critical driving displacement when the threaded connection structure is in a critical state according to the two target driving displacements, a fifth preset operation can also be performed on the two target driving displacements, and the obtained fifth operation result is used as the critical driving displacement. Among them, the fifth preset operation includes but is not limited to: taking an average value operation; or increasing or decreasing one of the target driving displacements by a fixed value, and the fixed value is less than the difference between the two target driving displacements; or using other operations for obtaining a value between the two target driving displacements.

[0167] When quantifying the critical driving displacement, the critical driving displacement can be directly used as the characterization value of the anti-loosening performance; or, a corresponding relationship is established in advance between the critical driving displacement and the characterization value. For example: a critical driving displacement within a value range corresponds to a characterization value, where the characterization value can be simplified to an anti-loosening ability level; or, a sixth preset operation is performed on the critical driving displacement, and the obtained sixth operation result is used as the characterization value. For example, a functional operation relationship is formed between the critical driving displacement and the characterization value through at least one calibrated constant, etc.

[0168] See Figure 9 , and another preferred embodiment of the present invention also provides a test method for the anti-loosening performance of a threaded connection structure, including;

[0169] Step S901, in the test links of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving displacement, and the pre-tightening force change curve of the threaded connection structure to be tested in each test link is obtained. Among them, the preset initial pre-tightening force is used as a characteristic variable for distinguishing each test link, each test link has a different preset initial pre-tightening force, and all test links are driven according to the same preset driving displacement;

[0170] Step S902: Process each pre-tightening force variation curve according to the pre-tightening force variation curve processing method, and determine two target test sessions.

[0171] Step S903: Obtain two preset initial pre-tightening forces corresponding to the two target test sessions as two target initial pre-tightening forces, and perform quantization processing on the target initial pre-tightening forces according to the fourth preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition.

[0172] In another preferred embodiment of the present invention, when testing the anti-loosening performance of the threaded connection structure, multiple test sessions are carried out in the vibration test, and different preset initial pre-tightening forces are applied to the threaded connection structure to be tested in each test session, and the threaded connection structure to be tested is periodically driven according to the same preset driving displacement. Since the preset initial pre-tightening forces in each test session are different, the preset initial pre-tightening force can be used as a characteristic variable to distinguish each test session. After obtaining the pre-tightening force variation curve of the threaded connection structure to be tested in each test session, according to the above-mentioned pre-tightening force variation curve processing method, each pre-tightening force variation curve is processed separately, and two target test sessions near the critical state between loosening and non-loosening of the threaded connection structure to be tested can be determined, that is, the threaded connection structure to be tested in one target test session is loosened, and the threaded connection structure to be tested in the other target test session is not loosened; taking the preset initial pre-tightening forces in the two target test sessions as target initial pre-tightening forces, and performing quantization processing on the two target initial pre-tightening forces according to the fourth preset quantization rule obtained or set in advance, the characterization value of the anti-loosening performance of the threaded connection structure of the same type as the threaded connection structure to be tested under the preset driving displacement condition can be obtained. By quantifying the anti-loosening performance of the threaded connection structure, the quantitative measurement and evaluation of the threaded connection structure can be realized. Furthermore, when the user selects a threaded connection structure, the user can select a suitable threaded connection structure according to the quantified value or evaluate whether the currently selected threaded connection structure is a suitable combination. At the same time, it is also convenient for the user to compare the anti-loosening performance of two different types or specifications of threaded connection structures.

[0173] It should be noted that the driving displacement is periodic. For convenience, an effective value or a maximum value can be selected to represent the driving displacement.

[0174] It should be noted that the critical initial pre-tightening force is the initial pre-tightening force corresponding to the critical state, that is, the initial pre-tightening force corresponding to the state where the threaded connection structure is between loosening and non-loosening.

[0175] Specifically, in the above-mentioned test method, the step of performing quantization processing on the target initial pre-tightening force according to the fourth preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition includes:

[0176] According to two target initial pre-tightening forces, take one of the target initial pre-tightening forces as the critical initial pre-tightening force; or perform a seventh preset operation on the two target initial pre-tightening forces, and take the obtained seventh operation result as the critical initial pre-tightening force;

[0177] According to the obtained critical initial pre-tightening force, take the critical initial pre-tightening force as the characterization value; or, determine the characterization value according to the corresponding relationship between the preset critical initial pre-tightening force and the characterization value; or, perform an eighth preset operation on the critical initial pre-tightening force, and take the obtained eighth operation result as the characterization value.

[0178] In a specific embodiment of the present invention, the second preset quantization rule is used to perform quantization processing on two target initial pre-tightening forces of a threaded connection structure with the same preset driving displacement. First, determine the critical initial pre-tightening force when the threaded connection structure is in a critical state according to the two target initial pre-tightening forces, that is, the initial pre-tightening force corresponding to the state between the loosening and non-loosening of the threaded connection structure, and then perform quantization on the critical initial pre-tightening force to obtain the characterization value of the anti-loosening performance of the threaded connection structure;

[0179] Among them, when determining the critical initial pre-tightening force when the threaded connection structure is in a critical state according to the two target initial pre-tightening forces, one of the two target initial pre-tightening forces can be selected as the critical initial pre-tightening force. In a preferred embodiment of the present invention, the target initial pre-tightening force when the threaded connection structure does not loosen is selected as the critical initial pre-tightening force, which is beneficial to ensuring that when the user selects the threaded connection structure according to the critical initial pre-tightening force, the requirement for anti-loosening performance can be met;

[0180] In addition, when determining the critical initial pre-tightening force when the threaded connection structure is in a critical state according to the two target initial pre-tightening forces, a seventh preset operation can also be performed on the two target initial pre-tightening forces, and the obtained seventh operation result is used as the critical initial pre-tightening force. Among them, the seventh preset operation includes but is not limited to: taking an average value operation; or increasing or decreasing one of the target initial pre-tightening forces by a fixed value, and the fixed value is less than the difference between the two target initial pre-tightening forces; or using other operations for obtaining a value between the two target initial pre-tightening forces.

[0181] When quantifying the critical initial pre-tightening force, the critical initial pre-tightening force can be directly used as the characterization value of the anti-loosening performance; or, a corresponding relationship is established in advance between the critical initial pre-tightening force and the characterization value. For example: a critical initial pre-tightening force within a value range corresponds to a characterization value, where the characterization value can be simplified to an anti-loosening ability level; or, an eighth preset operation is performed on the critical initial pre-tightening force, and the obtained eighth operation result is used as the characterization value. For example, a functional operation relationship is formed between the critical initial pre-tightening force and the characterization value through at least one calibrated constant, etc.

[0182] See Figure 10 , preferably, for the test method as described above, according to the pre-tightening force change curve processing method, processing each pre-tightening force change curve, and the steps of determining two target test links include:

[0183] Step S1001, according to the pre-tightening force change curve processing method, process each pre-tightening force change curve to determine the loosening condition of the threaded connection structure to be tested in each test link;

[0184] Step S1002, when in two adjacent test links, one threaded connection structure to be tested becomes loose and the other does not become loose, determine these two test links as two target test links, where two adjacent test links refer to: after sorting all test links according to the magnitude of the characteristic variable, the two adjacent test links before and after.

[0185] In a specific embodiment of the present invention, in the step of processing each pre-tightening force change curve and determining a target test link, first process according to the above-mentioned pre-tightening force change curve processing method to determine the loosening condition of the threaded connection structure to be tested in each test link; in addition, sort the test links according to the magnitude of the characteristic variable, and observe the change of the loosening condition with the characteristic variable. When in two adjacent test links before and after, one becomes loose and the other does not become loose, then these two adjacent test links are two target test links.

[0186] See Figure 11 , optionally, for the test method as described above, the test method further includes:

[0187] Step S1101, sort all test links according to the magnitude of the characteristic variable, and perform tests in sequence according to the obtained sorting to obtain the pre-tightening force change curve of the current test link;

[0188] Step S1102, process the pre-tightening force change curve of the current test link according to the pre-tightening force change curve processing method to obtain the loosening condition of the threaded connection structure in the current test link;

[0189] Step S1103, when the loosening condition of the threaded connection structure in the current test link is the same as that in the previous test link or when the current test link is the first test link, proceed to the next test link;

[0190] Step S1104, when the loosening condition of the threaded connection structure in the current test link is different from that in the previous test link, determine the current test link and the previous test link as target test links and stop the test.

[0191] In another preferred embodiment of the present invention, in the test execution stage, when obtaining the pre-tightening force change curve and processing the pre-tightening force change curve according to the pre-tightening force change curve processing method to determine the steps of two target test stages, first, sort the test stages according to the magnitude order of the characteristic variables, and perform tests in sequence to obtain the pre-tightening force change curve of the current test stage. Then, determine the loosening condition of the current test stage according to the pre-tightening force change curve. When the loosening condition of the current test stage is the same as that of the previous test stage or the current test stage is the first test stage, it is determined that the current test stage is not the target test stage at this time. At this time, the characteristic variables need to be updated and the next test stage is entered; when the loosening condition of the current test stage is different from that of the previous test stage, it can be determined that the current test stage and the previous test stage are the above-mentioned target test stages. At this time, the test can be stopped, so that fewer test stages are carried out in the whole test process, avoiding the waste of time and cost caused by still carrying out some test stages after the test purpose is achieved, and being beneficial to improving the test efficiency.

[0192] Preferably, according to different characteristic variables, when sorting the test stages, the test stages can be sorted from small to large or from large to small according to the correlation between the characteristic variables and the loosening result, ensuring that the loosening condition of the threaded connection structure to be tested in the test stage changes from no loosening to loosening; for example, the initial pre-tightening force is negatively correlated with the loosening result, that is, the greater the initial pre-tightening force, the less likely it is to loosen. Therefore, when sorting the test stages, they are arranged in descending order according to the initial pre-tightening force; the driving force is positively correlated with the loosening result, that is, the greater the driving force, the more likely it is to loosen. Therefore, when sorting the test stages, they are arranged in ascending order according to the driving force; the driving displacement is positively correlated with the loosening result, that is, the greater the driving displacement, the more likely it is to loosen. Therefore, when sorting the test stages, they are arranged in ascending order according to the driving displacement.

[0193] See Figure 12 , preferably, for the above-mentioned test method, the steps of obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test stage include:

[0194] Step S1201, detecting the pre-tightening force of the threaded connection structure to be tested;

[0195] Step S1202, when the pre-tightening force reaches the preset initial pre-tightening force of the current test stage, sending a test request message;

[0196] Step S1203: When receiving the test start signal, send the driving signal of the current test link to the driving mechanism, and start tracking and recording the monitored pre-tightening force to obtain the data of the pre-tightening force varying with the accumulation of test time, or obtain the data of the pre-tightening force varying with the accumulation of the number of vibration cycles. Among them, the driving signal carries the information of the preset driving frequency and the preset vibration cycle when controlling the driving of the driving mechanism, and also carries the information of the preset driving force or the preset driving displacement; vibration cycle

[0197] Step S1204: Obtain the pre-tightening force change curve of the current test link according to the data of the pre-tightening force varying with the accumulation of test time, or according to the data of the pre-tightening force varying with the accumulation of the number of vibration cycles.

[0198] In a preferred embodiment of the present invention, when obtaining the pre-tightening force change curve in each test link, the pre-tightening force of the threaded connection structure to be tested will be detected. Only when the pre-tightening force reaches the preset initial pre-tightening force of the current test link, it is determined that the current test link meets the condition for starting the test. At this time, the stop tightening operation information can be sent to the tightening mechanism or the technician, or the technician can actively stop the tightening operation and send a test request information, so that the technician or the control device knows that the current necessary conditions for starting the test have been met, which is beneficial to ensuring the accuracy of the test and avoiding errors caused by too large or too small initial pre-tightening force; after receiving the test start signal, start the test. At this time, the driving signal of the current test link will be sent to the driving mechanism, so that the driving mechanism drives according to the information of the preset vibration cycle, the preset driving frequency and the preset driving force in the driving signal, or drives according to the information of the preset vibration cycle, the preset driving frequency and the preset driving displacement in the driving signal, and starts to track and record the monitored current pre-tightening force, and then obtains the pre-tightening force change curve of the current test link according to the data of the pre-tightening force varying with the accumulation of time or the data of the pre-tightening force varying with the accumulation of the number of vibration cycles in this test link. The vibration cycle is the driving cycle for driving the threaded connection structure to be tested to vibrate.

[0199] Preferably, when driving the threaded connection structure to be tested according to the driving force or the driving displacement, it is preferably controlled by a closed-loop control method to avoid the influence of time or environmental factors on the amplitude, frequency and waveform of the driving force or the driving displacement, resulting in a situation without comparability.

[0200] It should also be noted here that the pre-tightening force described in the present invention is usually also referred to as the fastening force, which refers to the clamping force exerted by the threaded connection structure on the connected part. In the present invention, the pre-tightening force, the fastening force and the clamping force of the threaded connection structure have the same meaning and are not distinguished.

[0201] When testing the anti-loosening performance of a certain threaded connection structure using the above test method, to avoid the influence of wear and consumption of the threaded connection structure on the test, each set of samples of the threaded connection structure is only tested once. Here, the so-called "one test" means: using a set of samples and a set of preset test conditions, including initial pre-tightening force, driving force or driving displacement, vibration period, etc., to obtain a pre-tightening force change curve.

[0202] It should be noted here that the above test link refers to the test carried out under a set of preset test conditions, including initial pre-tightening force, driving force or driving displacement, vibration period, etc.; each test link corresponds to a set of specific preset test conditions, but can correspond to multiple sets of samples, that is, multiple sets of samples can be used to repeat the test according to the preset test conditions.

[0203] Preferably, when using the test method to test the anti-loosening performance of a certain threaded connection structure, all samples of the external threaded parts of the threaded connection structure to be tested are products of the same batch, and all samples of the internal threaded parts are also products of the same batch, which is beneficial to reducing the influence of individual differences between different samples on the test results.

[0204] See Figure 13 , yet another preferred embodiment of the present invention further provides a test device for the anti-loosening performance of a threaded connection structure, including:

[0205] A support plate 1, a connecting plate 2, a driving mechanism 3 and a first pressure sensor 4;

[0206] Among them, the connecting plate 2 is placed on the support plate 1 and fixedly connected through the threaded connection structure 5 to be tested;

[0207] The first pressure sensor 4 is arranged between the threaded connection structure 5 and the support plate 1 or the connecting plate 2 for monitoring the pre-tightening force of the threaded connection structure 5;

[0208] The driving mechanism 3 is connected to one end of the connecting plate 2, and the driving mechanism 3 is used to periodically apply a driving force in the test direction to the connecting plate 2, wherein the test direction is perpendicular to the extension direction of the helix of the threaded connection structure 5.

[0209] It should be noted here that the extension direction of the above helix is the threaded axis direction, as shown by i in Figure 13 .

[0210] In an embodiment of the present invention, the connecting plate 2 is placed on the support plate 1 and fixedly connected through the threaded connection structure 5 to be tested. When performing vibration test, the support plate 1 and the connecting plate 2 are used to simulate the pressed parts, providing a connection basis for the threaded connection structure 5 and facilitating the installation of the threaded connection structure 5. The support plate 1 is fixedly connected to a workbench. During the installation of the threaded connection structure 5, an extrusion force will be generated on the pressed parts simulated by the support plate 1 and the connecting plate 2. Since the first pressure sensor 4 is disposed between the threaded connection structure 5 and the support plate 1 or the connecting plate 2, when the threaded connection structure 5 extrudes the pressed parts, it will also extrude the first pressure sensor 4, enabling the first pressure sensor 4 to monitor the pre-tightening force of the threaded connection structure 5 during or after installation by monitoring the received extrusion force. The driving mechanism 3 is connected to one end of the connecting plate 2 and is used to periodically apply a driving force in the test direction to the connecting plate 2, thereby simulating the force condition of the pressed parts fixedly connected through the threaded connection structure 5 during long-term use. Preferably, the periodic driving force can be directly subjected to closed-loop control to prevent the amplitude, frequency, and waveform of the driving force from changing due to time factors during the test, resulting in a lack of comparability.

[0211] It should be noted that the test device may further include a controller, which is communicatively connected to the first pressure sensor 4 and the driving mechanism 3, enabling the pre-tightening force monitored by the first pressure sensor 4 to be uploaded to the controller. Then, the controller can draw a pre-tightening force change curve representing the process of the pre-tightening force changing with the accumulation of test time or the process of the pre-tightening force changing with the accumulation of the number of vibration cycles according to the received pre-tightening force, and process the pre-tightening force change curve according to the above pre-tightening force change curve processing method to obtain the loosening condition of the threaded connection structure 5 to be tested in the current test session. At the same time, a driving signal carrying information about the preset driving frequency and preset vibration cycle when controlling the driving of the driving mechanism, as well as information about the preset driving force or preset driving displacement, can be sent to the driving mechanism 3, enabling the driving mechanism 3 to perform periodic driving according to the driving signal.

[0212] It should be pointed out here that the driving mechanism 3 will also generate a driving displacement when generating the driving force, that is, the reciprocating displacement generated by the connecting plate 2 under the action of the driving force of the driving mechanism 3. The driving mechanism 3 can also perform periodic driving according to the driving displacement to simulate the force condition of the pressed parts fixedly connected through the threaded connection structure 5 during long-term use. Preferably, the periodic driving displacement can be subjected to closed-loop control to prevent the amplitude, frequency, and waveform of the driving displacement from changing due to time factors during the test, resulting in a lack of comparability. In actual operation, either closed-loop control of the driving force or closed-loop control of the driving displacement should be selected.

[0213] It should be noted here that under the action of the driving force or driving displacement, the pre-tightening force of the threaded connection structure 5 can change, usually decrease, and the continuous decrease of the pre-tightening force will lead to loosening failure.

[0214] In the embodiment of the present invention, through the first pressure sensor 4 and the driving mechanism 3, the pre-tightening force of the threaded connection structure 5 and the driving force or driving displacement applied to the connecting plate 2 can be obtained. By presetting the initial pre-tightening force, and presetting and performing closed-loop control on the driving force or driving displacement, the controller can obtain the pre-tightening force change curve under certain set conditions, and judge whether the threaded connection structure 5 loosens under this set condition according to the pre-tightening force change curve; further, by comparing the judgment results of the loosening conditions of the threaded connection structure 5 under different set conditions, the preset conditions corresponding to the critical state when the threaded connection structure 5 is between loosening and non-loosening can be obtained, including the initial pre-tightening force, the driving force or driving displacement, and then the anti-loosening performance of the threaded connection structure 5 can be quantitatively processed, so as to realize the quantitative measurement and evaluation of the anti-loosening performance of the threaded connection structure 5. Furthermore, when the user selects the threaded connection structure 5, the appropriate threaded connection structure 5 can be selected according to the quantified value, or it can be evaluated whether the currently selected threaded connection structure 5 is a suitable combination. At the same time, it is also convenient for the user to compare the anti-loosening performances of two different types or specifications of threaded connection structures 5.

[0215] Optionally, when quantitatively measuring and evaluating the anti-loosening performance of the threaded connection structure 5 based on the anti-loosening performance test device of the present invention, two test methods can be adopted:

[0216] Method 1: Perform closed-loop control on the driving force. At this time, one of the two variables of the initial pre-tightening force and the driving force can be kept unchanged, and the value of the other variable when the threaded connection structure 5 is in the critical state can be obtained, and then the comparison result can be obtained.

[0217] Method 2: Perform closed-loop control on the driving displacement. At this time, one of the two variables of the initial pre-tightening force and the driving displacement can be kept unchanged, and the value of the other variable when the threaded connection structure 5 is in the critical state can be obtained, and then the comparison result can be obtained.

[0218] It should be noted here that the critical state described in the present invention is the state representing between the loosening and non-loosening of the threaded connection structure 5.

[0219] It should also be noted that the above-mentioned controller can be a single control module or composed of multiple control modules. When composed of multiple control modules, each module can be arranged in different structures. For example, the control module for sending driving signals is arranged in the driving mechanism 3. The control module can be a physical structure or a software program in a processor with computing capabilities. When the control module executes or is executed, it can implement the above-mentioned test method for the anti-loosening performance of the threaded connection structure and / or the above-mentioned processing method for the pre-tightening force change curve.

[0220] In the embodiments of the present invention, the waveform of the driving force or driving displacement is preferably a sine wave or a triangular wave. Optionally, using other periodic waveforms as the waveform of the driving force or driving displacement for implementing closed-loop control also belongs to the protection scope of the present invention. The test direction is preferably perpendicular to the extension direction of the helix of the threaded connection structure 5, so as to simulate the radial force received by the threaded connection structure 5. Optionally, according to the different usage scenarios of the threaded connection structure 5, the test direction can be changed accordingly. For example, when the pressed part is mainly affected by the vibration force along the extension direction of the helix of the threaded connection structure 5, the extension direction of the helix of the threaded connection structure 5 is selected as the test direction.

[0221] See Figure 13 , specifically, for the above-mentioned test device, the threaded connection structure 5 includes: an internal threaded part 502 and an external threaded part 501;

[0222] Among them, the external threaded part 501 includes: a head 5011 provided with a stress structure and a threaded part provided with external threads;

[0223] Mounting holes for the external threaded part to pass through are provided on both the support plate 1 and the connecting plate 2. When the external threaded part 501 passes through the support plate 1 and the connecting plate 2, the first pressure sensor 4 is arranged between the support plate 1 and the head 5011 of the external threaded part 501 or the internal threaded part 502.

[0224] It should be noted here that when the external threaded part 501 passes through the support plate 1 and the connecting plate 2, there are two passing directions. When its head 5011 is on the outside of the support plate 1, the first pressure sensor 4 is arranged between the support plate 1 and the head 5011 of the external threaded part 501, that is Figure 1The manner shown; when the head 5011 of it is on the outer side of the connecting plate 2, the first pressure sensor 4 is arranged between the support plate 1 and the internal thread part 502. In the embodiment of the present invention, the threaded connection structure 5 includes: a mutually matching internal thread part 502 and an external thread part 501. Installation holes are provided on the support plate 1 and the connecting plate 2 to facilitate the penetration of the external thread part 501 and reduce the installation difficulty. At the same time, the aperture of the installation hole is larger than that of the external thread part 501, which is convenient for testing various types or specifications of the threaded connection structure 5 on the same set of support plate 1 and connecting plate 2, conducive to reducing costs and improving the versatility of the testing device. As can be seen from the above, the connecting plate 2 will receive the driving force applied by the driving mechanism 3, and there is a situation where the connecting plate 2 generates displacement under the action of the driving force. Therefore, setting the first pressure sensor 4 between the support plate 1 and the head 5011 of the external thread part 501 or the internal thread part 502 is conducive to avoiding the situation that the first pressure sensor 4 generates unnecessary errors in the detected pre-tightening force due to displacement, thereby ensuring the accuracy of the entire testing device.

[0225] Optionally, the threaded connection structure 5 further includes at least one gasket, and the gasket is arranged between the internal thread part 502 and the connecting plate 2, between the internal thread part 502 and the support plate 1, between the head 5011 of the external thread part 501 and the connecting plate 2, or between the head 5011 of the external thread part 501 and the support plate 1 for at least one of them, to simulate the real threaded connection environment, and at the same time reduce the friction of the threaded connection structure 5 on the support plate 1 or the connecting plate 2 and ensure the service life of the support plate 1 and the connecting plate 2. Similarly, a gasket can also be arranged between the first pressure sensor 4 and the head 5011 of the external thread part 501 or the internal thread part 502.

[0226] See Figure 13 , further, for the testing device as described above, a groove 101 is provided on the side of the support plate 1 away from the connecting plate 2, the first pressure sensor 4 is arranged in the groove 101, and the installation hole communicates with the groove 101.

[0227] In the embodiment of the present invention, a groove 101 is provided on the side of the support plate 1 away from the connecting plate 2, the first pressure sensor 4 is arranged in the groove 101, and the installation hole communicates with the groove 101; the setting of the groove 101 is conducive to ensuring the accuracy of the positioning and installation of the first pressure sensor 4 on the one hand, and at the same time is conducive to avoiding the displacement of the first pressure sensor 4 under the action of the friction force and / or driving force transmitted by the threaded connection structure 5, thereby ensuring the accuracy of the entire testing device.

[0228] See Figure 13 , preferably, for the testing device as described above, a second pressure sensor 6 is arranged between the connecting plate 2 and the driving mechanism 3, and the second pressure sensor 6 is also communicatively connected to the driving mechanism 3.

[0229] In an embodiment of the present invention, the test device further includes a second pressure sensor 6 disposed between the connecting plate 2 and the driving mechanism 3. The second pressure sensor 6 is communicatively connected to the driving mechanism 3, so that when the driving mechanism 3 drives according to a preset driving force, the second pressure sensor 6 can detect the actual driving force output by the driving mechanism 3 and feedback it to the driving mechanism 3, enabling the driving mechanism 3 to adjust according to the feedback actual driving force to form a closed-loop control, thereby ensuring that the error between the actual driving force output by the driving mechanism 3 and the preset driving force is small, which is conducive to ensuring the accuracy of the test.

[0230] See Figure 13 , specifically, the above-mentioned test device further includes: a displacement sensor 7, the displacement sensor 7 is communicatively connected to the driving mechanism 3, and the displacement sensor 7 is used to monitor the driving displacement of the connecting plate 2.

[0231] In an embodiment of the present invention, the test device further includes a displacement sensor 7 disposed on the connecting plate 2. The displacement sensor 7 is communicatively connected to the driving mechanism 3, so that when the driving mechanism 3 drives according to a preset driving displacement, the displacement sensor 7 can detect the actual driving displacement output by the driving mechanism 3 and feedback it to the driving mechanism 3, enabling the driving mechanism 3 to adjust according to the feedback actual driving displacement to form a closed-loop control, thereby ensuring that the error between the actual driving displacement output by the driving mechanism 3 and the preset driving displacement is small, which is conducive to ensuring the accuracy of the test.

[0232] Optionally, the above-mentioned second pressure sensor 6 and displacement sensor 7 can also be communicatively connected to the driving mechanism 3 through the above-mentioned controller, that is, the data detected by the second pressure sensor 6 and displacement sensor 7 are first uploaded to the controller, and then the controller feeds back to the driving mechanism 3 in the form of changing the information carried in the driving signal or directly forwarding, etc., so that the driving mechanism 3 performs closed-loop adjustment according to the feedback information.

[0233] Specifically, the above-mentioned test device further includes: a workbench;

[0234] The support plate 1 is fixedly installed on the workbench, and a process notch for installing the threaded connection structure 5 is provided on the workbench.

[0235] In an embodiment of the present invention, the workbench is used to fix the support plate 1, and the specific fixing methods include but are not limited to welding and screwing. The process notch can allow the threaded connection structure 5 to pass through and be installed, so that the support plate 1 can be arranged at the edge part or the middle part of the workbench, increasing the range of the fixed installation of the support plate 1 on the workbench.

[0236] Preferably, in the above-mentioned test device, a sliding mechanism is further provided between the support plate 1 and the connecting plate 2, and the sliding mechanism includes:

[0237] A guide rail provided on one of the support plate 1 and the connecting plate 2, and a corresponding guide groove provided on the other;

[0238] Or, a guide rail provided on one of the support plate 1 and the connecting plate 2, and corresponding rollers provided on the other;

[0239] Or, a guide groove provided on one of the support plate 1 and the connecting plate 2, and corresponding rollers provided on the other.

[0240] In an embodiment of the present invention, a sliding mechanism is provided between the support plate 1 and the connecting plate 2, which can reduce the friction between the support plate 1 and the connecting plate 2, is beneficial to the driving force being completely used to drive the connecting plate 2, and ensures the accuracy of the obtained results. The specific composition of the sliding mechanism is also given. Optionally, the above three forms of the sliding mechanism are only the preferred methods provided by the applicant. On this basis, the forms of the sliding mechanism obtained by those skilled in the art after adaptive modification also fall within the protection scope of the present invention. For example, corresponding guide grooves are respectively provided on the support plate 1 and the connecting plate 2, and balls are provided in the guide grooves.

[0241] In addition, the present invention may repeat reference numerals and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed.

[0242] It should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion.

[0243] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for processing a pre-tightening force change curve, characterized in that Including: Dividing the pre-tightening force change curve of the to-be-tested threaded connection structure obtained in the test session of the vibration test into multiple change stages according to a preset interval; Fitting the pre-tightening force change curve of each of the change stages respectively to obtain the change slope corresponding to each of the change stages; Processing all the change slopes according to a preset representation slope determination rule to obtain the representation slope of the pre-tightening force change curve, wherein the representation slope is used to determine the loosening condition of the to-be-tested threaded connection structure; The pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative test time, representing the process of the pre-tightening force changing with the cumulative test time, or the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative number of vibration cycles, representing the process of the pre-tightening force changing with the cumulative number of vibration cycles; The representation slope refers to a target slope value that can represent the slowest decay rate of the pre-tightening force on the pre-tightening force change curve, or an equivalent transformation form of the target slope value; The preset representation slope determination rule includes: comparing all the obtained change slopes, and taking the change slope with the smallest absolute value as the representation slope; or taking the absolute value of each of the obtained change slopes respectively, and taking the smallest absolute value as the representation slope; or performing normalization processing on each of the change slopes to obtain the corresponding normalized slope, and taking the smallest normalized slope as the representation slope, wherein the normalized slope is the ratio of the absolute value of the change slope to the initial value of the pre-tightening force, and the initial value of the pre-tightening force refers to the value of the preset initial pre-tightening force in the test session; After determining the representation slope, the processing method further includes: Comparing the representation slope with a preset slope threshold to obtain a comparison result; When the comparison result is that the absolute value of the representation slope is greater than the slope threshold, determining that the to-be-tested threaded connection structure is loosened; When the comparison result is that the absolute value of the representation slope is less than the slope threshold, determining that the to-be-tested threaded connection structure is not loosened.

2. A device for processing a pre-tightening force change curve, characterized in that Including: A first processing module for dividing the pre-tightening force change curve of the to-be-tested threaded connection structure obtained in the test session of the vibration test into multiple change stages according to a preset interval; A second processing module for fitting the pre-tightening force change curve of each of the change stages respectively to obtain the change slope corresponding to each of the change stages; A third processing module for processing all the change slopes according to a preset representation slope determination rule to obtain the representation slope of the pre-tightening force change curve, wherein the representation slope is used to determine the loosening condition of the to-be-tested threaded connection structure; The pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative test time, representing the process of the pre-tightening force changing with the cumulative test time, or the pre-tightening force change curve is a relationship curve between the pre-tightening force and the cumulative number of vibration cycles, representing the process of the pre-tightening force changing with the cumulative number of vibration cycles; The represented slope refers to a target slope value that can represent the slowest decay rate of the pre-tightening force on the pre-tightening force change curve, or an equivalent transformation form of the target slope value; The preset represented slope determination rule includes: comparing all the obtained change slopes, and taking the change slope with the smallest absolute value as the represented slope; or taking the absolute value of each of the obtained change slopes, and taking the smallest absolute value as the represented slope; or normalizing each change slope to obtain the corresponding normalized slope, and taking the smallest normalized slope as the represented slope, where the normalized slope is the ratio of the absolute value of the change slope to the initial value of the pre-tightening force, and the initial value of the pre-tightening force refers to the value of the preset initial pre-tightening force in the test session; The processing device further includes: A fourth processing module, configured to compare the represented slope with a preset slope threshold to obtain a comparison result; A fifth processing module, configured to determine that the threaded connection structure to be tested is loose when the comparison result is that the absolute value of the represented slope is greater than the slope threshold; A sixth processing module, configured to determine that the threaded connection structure to be tested is not loose when the comparison result is that the absolute value of the represented slope is less than the slope threshold.

3. A test method for the anti-loosening performance of a threaded connection structure, characterized in that, It includes: In the test sessions of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving force, and the pre-tightening force change curve of the threaded connection structure to be tested in each test session is obtained, where the preset driving force is used as a characteristic variable for distinguishing each test session, each test session is driven according to a different preset driving force, and all the test sessions have the same preset initial pre-tightening force; According to the pre-tightening force change curve processing method as described in claim 1, each of the pre-tightening force change curves is processed, and two target test sessions are determined; Two preset driving forces corresponding to the two target test sessions are obtained as two target driving forces, and the two target driving forces are quantitatively processed according to a first preset quantization rule to obtain a representation value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition.

4. The test method according to claim 3, characterized in that, The step of quantitatively processing the two target driving forces according to the first preset quantization rule to obtain a representation value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition includes: According to the two target driving forces, taking one of the target driving forces as the critical driving force; or performing a first preset operation on the two target driving forces, and taking the obtained first operation result as the critical driving force; According to the obtained critical driving force, taking the critical driving force as the representation value; or determining the representation value according to the corresponding relationship between the preset critical driving force and the representation value; or performing a second preset operation on the critical driving force, and taking the obtained second operation result as the representation value.

5. A test method for the anti-loosening performance of a threaded connection structure, characterized in that, It includes: In the test process of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving force, and the pre-tightening force change curve of the threaded connection structure to be tested in each test process is obtained. Among them, the preset initial pre-tightening force is used as a characteristic variable to distinguish each test process. Each of the test processes has a different preset initial pre-tightening force, and all of the test processes are driven according to the same preset driving force; According to the pre-tightening force change curve processing method described in claim 1, each of the pre-tightening force change curves is processed, and two target test processes are determined; The two preset initial pre-tightening forces corresponding to the two target test processes are obtained as two target initial pre-tightening forces, and the two target initial pre-tightening forces are quantitatively processed according to a second preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force condition.

6. The test method according to claim 5, characterized in that, The step of quantitatively processing the two target initial pre-tightening forces according to the second preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset driving force condition includes: According to the two target initial pre-tightening forces, one of the target initial pre-tightening forces is used as the critical initial pre-tightening force; or a third preset operation is performed on the two target initial pre-tightening forces, and the obtained third operation result is used as the critical initial pre-tightening force; According to the obtained critical initial pre-tightening force, the critical initial pre-tightening force is used as the characterization value; or, the characterization value is determined according to the corresponding relationship between the preset critical initial pre-tightening force and the characterization value; or, a fourth preset operation is performed on the critical initial pre-tightening force, and the obtained fourth operation result is used as the characterization value.

7. A test method for the anti-loosening performance of a threaded connection structure, characterized in that, Includes: In the test process of multiple vibration tests, the threaded connection structure to be tested is periodically driven according to a preset driving displacement, and the pre-tightening force change curve of the threaded connection structure to be tested in each test process is obtained. Among them, the preset driving displacement is used as a characteristic variable to distinguish each test process. Each of the test processes is driven according to a different preset driving displacement, and all of the test processes have the same preset initial pre-tightening force; According to the pre-tightening force change curve processing method described in claim 1, each of the pre-tightening force change curves is processed, and two target test processes are determined; The two preset driving displacements corresponding to the two target test processes are obtained as two target driving displacements, and the two target driving displacements are quantitatively processed according to a third preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition.

8. The test method according to claim 7, characterized in that The step of quantitatively processing the two target driving displacements according to the third preset quantization rule to obtain a characterization value of the anti-loosening performance of the threaded connection structure under the preset initial pre-tightening force condition includes: According to the two target driving displacements, one of the target driving displacements is used as the critical driving displacement; or a fifth preset operation is performed on the two target driving displacements, and the obtained fifth operation result is used as the critical driving displacement; Based on the obtained critical driving displacement, use the critical driving displacement as the characterization value; or, determine the characterization value according to the corresponding relationship between the preset critical driving displacement and the characterization value; or, perform a sixth preset operation on the critical driving displacement, and use the obtained sixth operation result as the characterization value.

9. A test method for the anti-loosening performance of a threaded connection structure, characterized in that, Include; In the test session of multiple vibration tests, periodically drive the threaded connection structure to be tested according to the preset driving displacement, and obtain the pre-tightening force change curve of the threaded connection structure to be tested in each test session. Among them, the preset initial pre-tightening force is used as the characteristic variable to distinguish each test session. Each of the test sessions has a different preset initial pre-tightening force, and all the test sessions are driven according to the same preset driving displacement; According to the pre-tightening force change curve processing method described in claim 1, process each of the pre-tightening force change curves and determine two target test sessions; Obtain the two preset initial pre-tightening forces corresponding to the two target test sessions as two target initial pre-tightening forces, and perform quantization processing on the target initial pre-tightening forces according to the fourth preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition.

10. The test method according to claim 9, characterized in that, The step of performing quantization processing on the target initial pre-tightening forces according to the fourth preset quantization rule to obtain the characterization value of the anti-loosening performance of the threaded connection structure under the preset driving displacement condition includes: According to the two target initial pre-tightening forces, use one of the target initial pre-tightening forces as the critical initial pre-tightening force; or perform a seventh preset operation on the two target initial pre-tightening forces, and use the obtained seventh operation result as the critical initial pre-tightening force; Based on the obtained critical initial pre-tightening force, use the critical initial pre-tightening force as the characterization value; or, determine the characterization value according to the corresponding relationship between the preset critical initial pre-tightening force and the characterization value; or, perform an eighth preset operation on the critical initial pre-tightening force, and use the obtained eighth operation result as the characterization value.

11. The test method according to any one of claims 3-10, characterized in that, The step of according to the pre-tightening force change curve processing method described in claim 1, processing each of the pre-tightening force change curves and determining two target test sessions includes: According to the pre-tightening force change curve processing method, process each of the pre-tightening force change curves to determine the loosening condition of the threaded connection structure to be tested in each test session; When, in two adjacent test sessions, one of the threaded connection structures to be tested becomes loose and the other does not become loose, determine these two test sessions as the two target test sessions; among them, two adjacent test sessions refer to: after sorting all the test sessions according to the magnitude of the characteristic variable, the two test sessions adjacent before and after.

12. The test method according to any one of claims 3-10, characterized in that, The test method further includes: Sort all the test sessions according to the magnitude of the characteristic variable, and perform tests in sequence according to the obtained sorting to obtain the pre-tightening force change curve of the current test session; Process the pre-tightening force change curve of the current test link according to the pre-tightening force change curve processing method to obtain the loosening condition of the threaded connection structure in the current test link; When the loosening condition of the threaded connection structure in the current test link is the same as that in the previous test link or when the current test link is the first test link, proceed to the next test link; When the loosening condition of the threaded connection structure in the current test link is different from that in the previous test link, determine the current test link and the previous test link as the two target test links and stop the test.

13. The test method according to any one of claims 3-10, characterized in that The step of obtaining the pre-tightening force change curve of the threaded connection structure to be tested in each test link includes: Detect the pre-tightening force of the threaded connection structure to be tested; When the pre-tightening force reaches the preset initial pre-tightening force of the current test link, send a test request message; When receiving the test start signal, send the drive signal of the current test link to the drive mechanism and start tracking and recording the monitored pre-tightening force to obtain the data of the pre-tightening force changing with the accumulation of test time, or obtain the data of the pre-tightening force changing with the accumulation of the number of vibration cycles. Among them, the drive signal carries the information of the preset drive frequency and preset vibration cycle when controlling the drive mechanism to drive, and also carries the information of the preset driving force or preset driving displacement; Obtain the pre-tightening force change curve of the current test link according to the data of the pre-tightening force changing with the accumulation of test time, or according to the data of the pre-tightening force changing with the accumulation of the number of vibration cycles.

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