A fatigue monitoring system for trailer leaf springs

Abstract

The present invention relates to the field of fatigue monitoring, and in particular to a fatigue monitoring system for trailer leaf springs, comprising: a data acquisition module provided with a displacement acquisition unit, a temperature acquisition unit, a sound acquisition unit and an image acquisition unit; a data processing module for preliminarily determining whether a single leaf spring fluctuation meets a fatigue fluctuation preset standard based on a leaf spring deformation amount, and for secondarily determining whether a single leaf spring fluctuation meets a fatigue fluctuation preset standard based on an acceleration limit value of the single leaf spring fluctuation; a fatigue determination module for preliminarily determining whether a leaf spring meets a pre-fatigue preset standard based on an average loudness of a characteristic sound within an effective fluctuation period, for secondarily determining whether a leaf spring meets a pre-fatigue preset standard based on a temperature rise limit value of the leaf spring within the effective fluctuation period, and for determining the reason why the leaf spring meets the pre-fatigue preset standard based on a limit change gap characteristic value; and a display module, so as to realize real-time monitoring and early warning of the fatigue state of the trailer leaf spring.

Description

Technical Field

[0001] The invention relates to the field of fatigue monitoring, and in particular to a fatigue monitoring system for trailer leaf springs. Background Art

[0002] Trailer leaf spring is an elastic element in the automobile suspension system, usually composed of multiple spring steel sheets with rectangular cross-sections, with high elasticity and load-bearing capacity. Its function is to support the weight of the vehicle, while mitigating the impact and vibration caused by the road surface, ensuring the vehicle's driving stability and riding comfort. Leaf springs will break due to metal fatigue after long-term use, so fatigue tests are required on leaf springs on trailers that have traveled hundreds of thousands of kilometers to ensure the reliability and safety of leaf springs.

[0003] The existing technology usually uses a fatigue test device in a laboratory environment to simulate the fatigue limit of the leaf spring and the number of cyclic stresses when fatigue failure occurs, and then obtains the stress cycle threshold of the leaf spring based on data statistics. However, in actual use, the working conditions of trailers are relatively complex, and the service life of the leaf spring is closely related to many aspects such as driving conditions, overloading, and operating conditions. The complex operating environment and working conditions make it difficult to accurately grasp the fatigue state of the leaf spring.

[0004] Chinese Patent Publication No.: CN117664550B discloses a leaf spring fatigue testing device, which includes a frame, a load output mechanism and a base; it also includes a force-applying seat and a force-bearing seat; a plurality of pushing members are provided on the force-applying seat, and a corresponding pushing member is provided on the force-bearing seat, and at least one of the pushing member and the corresponding pushing member is provided with a wedge surface; a driving unit is provided on the force-applying seat and / or the force-bearing seat to drive the pushing member and / or the pushing member to slide, so that the pushing member and the pushing member can abut against each other through the wedge surface, or the pushing member and the pushing member are separated from each other; when at least one of the pushing members abuts against the corresponding pushing member, the pushing member presses down the pushing member through the guidance of the corresponding wedge surface, which will apply vertical load and horizontal direction to the leaf spring. It can be seen that the above technical solution uses a leaf spring fatigue testing device to simulate the stress of the leaf spring, and the leaf spring fatigue test cycle is long and the conclusion is inaccurate. Summary of the invention

[0005] To this end, the present invention provides a fatigue monitoring system for trailer leaf springs, which is used to overcome the problems in the prior art of using a leaf spring fatigue testing device to simulate the stress of the leaf spring, and the leaf spring fatigue testing cycle is long and the conclusion is inaccurate.

[0006] To achieve the above object, the present invention provides a fatigue monitoring system for trailer leaf springs, comprising:

[0007] A data acquisition module, comprising a displacement acquisition unit disposed on the inner top surface of two coil ears of the leaf spring for acquiring deformation amount information and deformation acceleration information of the leaf spring, a temperature acquisition unit disposed on one side adjacent to the displacement acquisition unit for acquiring temperature information of the leaf spring, a sound acquisition unit disposed on the top surface of the leaf spring for acquiring sound information of the leaf spring, and an image acquisition unit disposed at the center of the axle for acquiring image information of the leaf spring;

[0008] A data processing module, which is connected to the data acquisition module, is used to preliminarily determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the deformation of the leaf spring, and to secondarily determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation, or to record the single fluctuation as a type of fluctuation, and to determine the effective fluctuation period according to the fluctuation frequency and the proportion of the type of fluctuation within the preset period;

[0009] a fatigue determination module, which is connected to the data acquisition module and the data processing module, and is used to preliminarily determine whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound in the effective fluctuation period, and to secondarily determine whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring in the effective fluctuation period, or to determine the reason why the leaf spring meets the pre-fatigue preset standard according to the limit change gap characteristic value;

[0010] A display module is connected to the fatigue determination module and is used to display the warning information of the fatigue determination module.

[0011] Furthermore, the data processing module preliminarily determines whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard according to the leaf spring deformation, wherein:

[0012] If the leaf spring deformation is greater than or equal to the first preset deformation and less than the second preset deformation, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and secondarily determines whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation;

[0013] If the leaf spring deformation is greater than or equal to the second preset deformation, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

[0014] Furthermore, the data processing module secondarily determines whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard according to the acceleration limit value of the single leaf spring fluctuation, wherein:

[0015] If the acceleration limit value of the single leaf spring fluctuation is less than the first preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation does not meet the preset fatigue fluctuation standard;

[0016] If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the first preset acceleration limit value and less than the second preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a second-class fluctuation;

[0017] If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the second preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

[0018] Further, in response to the fluctuation frequency within the preset time period being greater than or equal to the preset frequency threshold and the fluctuation proportion of the first type being greater than or equal to the preset proportion threshold, the data processing module determines that the time period meets the preset standard of the fatigue time period, and records the time period as a valid fluctuation time period;

[0019] The fluctuation frequency within a preset time period is the sum of the frequency of the first type of fluctuation and the frequency of the second type of fluctuation within the time period.

[0020] Furthermore, the fatigue determination module preliminarily determines whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound in the effective fluctuation period, wherein:

[0021] If the average loudness is less than a first preset loudness, the fatigue determination module preliminarily determines that the leaf spring does not meet the pre-fatigue preset standard;

[0022] If the average loudness is greater than or equal to the first preset loudness and less than the second preset loudness, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and secondarily determines whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring within the effective fluctuation period;

[0023] If the average loudness is greater than or equal to the second preset loudness, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and determines the reason why the leaf spring meets the pre-fatigue preset standard according to the limit variation gap characteristic value.

[0024] Furthermore, the limit variation gap characteristic value is the average of the maximum gaps of each layer of the leaf spring in the first type of fluctuation and the second type of fluctuation within the effective fluctuation period, and the maximum gap is obtained by the image acquisition unit.

[0025] Furthermore, the fatigue determination module secondarily determines whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring within the effective fluctuation period, wherein:

[0026] If the temperature rise limit value of the leaf spring is less than the first preset temperature threshold, the fatigue determination module secondarily determines that the leaf spring does not meet the pre-fatigue preset standard;

[0027] If the temperature rise limit value of the leaf spring is greater than or equal to the first preset temperature threshold, the fatigue determination module secondarily determines that the leaf spring meets the pre-fatigue preset standard and issues a pre-fatigue state warning.

[0028] Furthermore, the fatigue determination module determines, based on the limit change gap characteristic value, that the reasons why the leaf spring meets the pre-fatigue preset standard include leaf spring lubrication failure, or leaf spring jacket loosening; an alarm of leaf spring lubrication failure is issued when the leaf spring lubrication fails, and an alarm of leaf spring jacket loosening is issued when the leaf spring jacket loosens.

[0029] Furthermore, in response to the temperature rise limit value of the leaf spring within the effective fluctuation period being greater than or equal to the second preset temperature threshold, the fatigue determination module corrects the first preset displacement and the second preset displacement by the same amplitude according to the difference between the temperature rise limit value and the second preset temperature threshold.

[0030] Furthermore, the fatigue determination module is provided with several correction methods for reducing the first preset displacement and the second preset displacement, and each correction method has a different correction amplitude for the first preset displacement and the second preset displacement.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention collects leaf spring data information in multiple dimensions to obtain accurate and reasonable judgment indicators through a data acquisition module provided with displacement, temperature, sound and image data acquisition units; the data processing module determines the fatigue state of a single fluctuation based on the leaf spring deformation, the acceleration limit value of a single leaf spring fluctuation and the fluctuation, and accurately identifies the fatigue period of the leaf spring; the fatigue determination module verifies the fatigue state of the leaf spring based on the average loudness of the leaf spring, the temperature rise limit value and the limit change gap characteristic value, and issues fatigue warning information through the display module, thereby realizing real-time and accurate monitoring and immediate warning of the fatigue state of the trailer leaf spring.

[0032] Furthermore, the present invention preliminarily determines whether a single leaf spring fluctuation meets a preset fatigue fluctuation standard according to the leaf spring deformation through a data processing module, and classifies the single leaf spring fluctuation, thereby realizing accurate identification of leaf spring fatigue fluctuation.

[0033] Furthermore, the present invention uses a data processing module to secondary determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation, and divides the single leaf spring fluctuation that meets the preset standard of fatigue fluctuation into Class I fluctuation and Class II fluctuation, thereby improving the accuracy of leaf spring fatigue fluctuation assessment.

[0034] Furthermore, the present invention determines that the time period meets the preset standard of the fatigue period by the data processing module when the fluctuation frequency within the preset time period is greater than or equal to the preset frequency threshold and the proportion of the first type of fluctuation is greater than or equal to the preset proportion threshold, and records the time period as a valid fluctuation period, while considering the influence of the fluctuation frequency and the proportion of the first type of fluctuation, thereby improving the accuracy of the judgment of the fatigue period of the leaf spring.

[0035] Furthermore, the present invention preliminarily determines whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound in the effective fluctuation period through the fatigue determination module, thereby improving the reliability of leaf spring fatigue monitoring.

[0036] Furthermore, the present invention uses a fatigue determination module to secondary determine whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring within the effective fluctuation period, and determines the state of the leaf spring based on actual temperature data, thereby improving the scientific nature of leaf spring fatigue state monitoring.

[0037] Furthermore, the present invention determines the reason why the leaf spring meets the pre-fatigue preset standard according to the limit change gap characteristic value through the fatigue determination module, and promptly identifies the cause of leaf spring fatigue, thereby avoiding unnecessary maintenance.

[0038] Furthermore, the present invention quantifies the evaluation index of the leaf spring fatigue state by setting the limit variation gap characteristic value, thereby improving the objectivity of the leaf spring fatigue monitoring system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of a fatigue monitoring system for trailer leaf springs according to an embodiment of the present invention;

[0040] Figure 2 A flowchart for preliminarily determining whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard in an embodiment of the present invention;

[0041] Figure 3 A flowchart for preliminarily determining whether the leaf spring meets the pre-fatigue preset standard according to an embodiment of the present invention;

[0042] Figure 4 The flowchart of the embodiment of the present invention is to determine the reason why the leaf spring meets the pre-fatigue preset standard. DETAILED DESCRIPTION

[0043] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] It should be pointed out that the data in this embodiment are obtained by comprehensive analysis and evaluation of the historical test data and the corresponding historical test results of the present invention in the three months before this test. It can be understood by those skilled in the art that the determination method of the system of the present invention for the above-mentioned single parameter can be to select the value with the highest proportion as the preset standard parameter according to the data distribution, use weighted summation to use the obtained value as the preset standard parameter, substitute each historical data into a specific formula and use the value obtained by the formula as the preset standard parameter or other selection methods, as long as the system of the present invention can clearly define the different specific situations in the single determination process through the obtained values.

[0045] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0046] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively a schematic diagram of the structure of the fatigue monitoring system for trailer leaf springs according to an embodiment of the present invention; a flowchart of the embodiment of the present invention for preliminarily determining whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation; a flowchart of the embodiment of the present invention for preliminarily determining whether the leaf spring meets the preset standard of pre-fatigue; and a flowchart of the embodiment of the present invention for determining the reason why the leaf spring meets the preset standard of pre-fatigue.

[0047] An embodiment of the present invention provides a fatigue monitoring system for a trailer leaf spring, comprising:

[0048] A data acquisition module, comprising a displacement acquisition unit disposed on the inner top surface of two coil ears of the leaf spring for acquiring deformation amount information and deformation acceleration information of the leaf spring, a temperature acquisition unit disposed on one side adjacent to the displacement acquisition unit for acquiring temperature information of the leaf spring, a sound acquisition unit disposed on the top surface of the leaf spring for acquiring sound information of the leaf spring, and an image acquisition unit disposed at the center of the axle for acquiring image information of the leaf spring;

[0049] A data processing module, which is connected to the data acquisition module, is used to preliminarily determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the deformation of the leaf spring, and to secondarily determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation, or to record the single fluctuation as a type of fluctuation, and to determine the effective fluctuation period according to the fluctuation frequency and the proportion of the type of fluctuation within the preset period;

[0050] a fatigue determination module, which is connected to the data acquisition module and the data processing module, and when the leaf spring is preliminarily determined to meet the pre-fatigue preset standard according to the average loudness of the characteristic sound in the effective fluctuation period, a secondary determination is made as to whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring in the effective fluctuation period, or the reason why the leaf spring meets the pre-fatigue preset standard is determined according to the limit change gap characteristic value;

[0051] A display module is connected to the fatigue determination module and is used to display the warning information of the fatigue determination module.

[0052] Specifically, pre-fatigue is the operating period when the leaf spring is close to the fatigue state. It can be understood that fatigue is an uncertain state. Usually, the fatigue stress range or the number of cyclic loading is fitted through a large amount of experimental data. In this embodiment, after the leaf spring has pre-fatigue, fatigue damage occurs after a certain number of cyclic loadings.

[0053] Specifically, the temperature acquisition unit can be a fiber optic temperature sensor, which is used to accurately collect the temperature of the point where fatigue damage first occurs in the historical leaf spring fatigue test; the sound acquisition unit can be an acoustic sensor; the displacement acquisition unit can be a potentiometer displacement sensor, and the collected leaf spring deformation is the change between the position of the point where fatigue damage first occurs in the historical leaf spring fatigue test after the trailer is bumped and the initial leaf spring position; the image acquisition unit can be a CCD camera, a camera, or a sensor that can obtain leaf spring information in real time, without specific limitation.

[0054] It can be understood by those skilled in the art that the specific structures of the data processing module and fatigue determination module of this embodiment are not limited, and they themselves and each unit therein can be composed of logic components, including field programmable components, computers or microprocessors in computers.

[0055] Specifically, the data processing module preliminarily determines whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard according to the leaf spring deformation, wherein:

[0056] If the leaf spring deformation is less than the first preset deformation of 4.23 cm, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation and records it as invalid fluctuation;

[0057] If the leaf spring deformation is greater than or equal to the first preset deformation and less than the second preset deformation of 6.98 cm, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and secondarily determines whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation;

[0058] If the leaf spring deformation is greater than or equal to the second preset deformation, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

[0059] Specifically, the data processing module determines whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard based on the acceleration limit value of the single leaf spring fluctuation.

[0060] If the acceleration limit value of the single leaf spring fluctuation is less than the first preset acceleration limit value of 0.224 m / s 2 , the data processing module secondarily determines that the single leaf spring fluctuation does not meet the preset fatigue fluctuation standard;

[0061] If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the first preset acceleration limit value and less than the second preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a second-class fluctuation;

[0062] If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the second preset acceleration limit value of 0.375 m / s 2 , the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

[0063] Specifically, the data processing module determines that the period meets the preset standard of the fatigue period in response to the fluctuation frequency within the preset period of 5 minutes being greater than or equal to the preset frequency threshold of 22 times / min and the proportion of the first type of fluctuation being greater than or equal to the preset proportion threshold of 0.66, and records the period as a valid fluctuation period;

[0064] The fluctuation frequency within a preset time period is the sum of the frequency of the first type of fluctuation and the frequency of the second type of fluctuation within the time period.

[0065] Specifically, the fatigue determination module preliminarily determines whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound within the effective fluctuation period, wherein:

[0066] If the average loudness is less than the first preset loudness of 80.50 dB, the fatigue determination module preliminarily determines that the leaf spring does not meet the pre-fatigue preset standard;

[0067] If the average loudness is greater than or equal to the first preset loudness and less than the second preset loudness of 92.40 dB, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and secondarily determines whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring within the effective fluctuation period;

[0068] If the average loudness is greater than or equal to the second preset loudness, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and determines the reason why the leaf spring meets the pre-fatigue preset standard according to the limit variation gap characteristic value.

[0069] Specifically, the limit variation gap characteristic value is the average of the maximum gaps of each layer of the leaf spring in the first type of fluctuation and the second type of fluctuation within the effective fluctuation period, and the maximum gap is obtained by the image acquisition unit.

[0070] Specifically, the fatigue determination module determines whether the leaf spring meets the pre-fatigue preset standard based on the temperature rise limit value of the leaf spring within the effective fluctuation period.

[0071] If the temperature rise limit value of the leaf spring is less than the first preset temperature threshold value of 85.62° C., the fatigue determination module secondarily determines that the leaf spring does not meet the pre-fatigue preset standard;

[0072] If the temperature rise limit value of the leaf spring is greater than or equal to the first preset temperature threshold, the fatigue determination module secondarily determines that the leaf spring meets the pre-fatigue preset standard and issues a pre-fatigue state warning.

[0073] Specifically, the fatigue determination module determines the reason why the leaf spring meets the pre-fatigue preset standard according to the limit change gap characteristic value, wherein:

[0074] If the limit variation gap characteristic value is less than the preset gap characteristic value of 1.21 mm, the fatigue determination module determines that the reason why the leaf spring meets the pre-fatigue preset standard is that the leaf spring lubrication fails, and issues a leaf spring lubrication failure warning;

[0075] If the limit variation gap characteristic value is greater than or equal to the preset gap characteristic value, the fatigue determination module determines that the reason why the leaf spring meets the pre-fatigue preset standard is that the leaf spring jacket is loose, and issues a warning that the leaf spring jacket is loose.

[0076] Specifically, in response to the temperature rise limit value of the leaf spring in the effective fluctuation period being greater than or equal to the second preset temperature threshold value 115.00°C, the fatigue determination module corrects the first preset displacement and the second preset displacement by the same amplitude according to the difference between the temperature rise limit value and the second preset temperature threshold value.

[0077] Specifically, the fatigue determination module is provided with several correction methods for reducing the first preset displacement and the second preset displacement, wherein:

[0078] If the temperature difference is less than the first preset temperature difference of 5.50° C., the fatigue determination module uses a first preset correction coefficient of 0.98 to correct the first preset displacement and the second preset displacement to corresponding values ​​by the same amplitude;

[0079] If the temperature difference is greater than or equal to the first preset temperature difference and less than the second preset temperature difference of 12.87°C, the fatigue determination module uses the second preset correction coefficient of 0.96 to correct the first preset displacement and the second preset displacement to corresponding values ​​by the same amplitude;

[0080] If the temperature difference is greater than or equal to the second preset temperature difference, the fatigue determination module uses a third preset correction coefficient of 0.94 to correct the first preset displacement and the second preset displacement to corresponding values ​​with the same amplitude;

[0081] The temperature difference is the difference between the temperature rise limit value and the second preset temperature threshold.

[0082] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A fatigue monitoring system for trailer leaf springs, characterized in that: include: A data acquisition module, comprising a displacement acquisition unit disposed on the inner top surface of two coil ears of the leaf spring for acquiring deformation amount information and deformation acceleration information of the leaf spring, a temperature acquisition unit disposed on one side adjacent to the displacement acquisition unit for acquiring temperature information of the leaf spring, a sound acquisition unit disposed on the top surface of the leaf spring for acquiring sound information of the leaf spring, and an image acquisition unit disposed at the center of the axle for acquiring image information of the leaf spring; A data processing module, which is connected to the data acquisition module, is used to preliminarily determine whether a single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the deformation of the leaf spring, and to secondarily determine whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation, or to record the single fluctuation as a type of fluctuation, and to determine the effective fluctuation period according to the fluctuation frequency and the proportion of the type of fluctuation within the preset period; a fatigue determination module, which is connected to the data acquisition module and the data processing module, and is used to preliminarily determine whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound in the effective fluctuation period, and to secondarily determine whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring in the effective fluctuation period, or to determine the reason why the leaf spring meets the pre-fatigue preset standard according to the limit change gap characteristic value; A display module is connected to the fatigue determination module and is used to display the warning information of the fatigue determination module.

2. The fatigue monitoring system for trailer leaf springs according to claim 1, characterized in that: The data processing module preliminarily determines that the single leaf spring fluctuation meets the preset fatigue fluctuation standard according to the leaf spring deformation, wherein: If the leaf spring deformation is greater than or equal to the first preset deformation and less than the second preset deformation, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and secondarily determines whether the single leaf spring fluctuation meets the preset standard of fatigue fluctuation according to the acceleration limit value of the single leaf spring fluctuation; If the leaf spring deformation is greater than or equal to the second preset deformation, the data processing module preliminarily determines that the leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

3. The fatigue monitoring system for trailer leaf springs according to claim 2, characterized in that: The data processing module determines whether the single leaf spring fluctuation meets the preset fatigue fluctuation standard based on the acceleration limit value of the single leaf spring fluctuation. If the acceleration limit value of the single leaf spring fluctuation is less than the first preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation does not meet the preset fatigue fluctuation standard; If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the first preset acceleration limit value and less than the second preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a second-class fluctuation; If the acceleration limit value of the single leaf spring fluctuation is greater than or equal to the second preset acceleration limit value, the data processing module secondarily determines that the single leaf spring fluctuation meets the preset standard of fatigue fluctuation, and records the single fluctuation as a type of fluctuation.

4. The fatigue monitoring system for trailer leaf springs according to claim 3, characterized in that: The data processing module determines that the period meets the preset standard of fatigue period in response to the fluctuation frequency within the preset period being greater than or equal to the preset frequency threshold and the fluctuation proportion of the one type being greater than or equal to the preset proportion threshold, and records the period as a valid fluctuation period; The fluctuation frequency within a preset time period is the sum of the frequency of the first type of fluctuation and the frequency of the second type of fluctuation within the time period.

5. The fatigue monitoring system for trailer leaf springs according to claim 4, characterized in that: The fatigue determination module preliminarily determines whether the leaf spring meets the pre-fatigue preset standard according to the average loudness of the characteristic sound within the effective fluctuation period, wherein: If the average loudness is less than a first preset loudness, the fatigue determination module preliminarily determines that the leaf spring does not meet the pre-fatigue preset standard; If the average loudness is greater than or equal to the first preset loudness and less than the second preset loudness, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and secondarily determines whether the leaf spring meets the pre-fatigue preset standard according to the temperature rise limit value of the leaf spring within the effective fluctuation period; If the average loudness is greater than or equal to the second preset loudness, the fatigue determination module preliminarily determines that the leaf spring meets the pre-fatigue preset standard, and determines the reason why the leaf spring meets the pre-fatigue preset standard according to the limit variation gap characteristic value.

6. The fatigue monitoring system for trailer leaf springs according to claim 5, characterized in that: The limit variation gap characteristic value is the average of the maximum gaps of each layer of the leaf spring in the first type of fluctuation and the second type of fluctuation within the effective fluctuation period, and the maximum gap is obtained by the image acquisition unit.

7. The fatigue monitoring system for trailer leaf springs according to claim 6, characterized in that: The fatigue determination module determines whether the leaf spring meets the pre-fatigue preset standard for a second time according to the temperature rise limit value of the leaf spring within the effective fluctuation period, wherein: If the temperature rise limit value of the leaf spring is less than the first preset temperature threshold, the fatigue determination module secondarily determines that the leaf spring does not meet the pre-fatigue preset standard; If the temperature rise limit value of the leaf spring is greater than or equal to the first preset temperature threshold, the fatigue determination module secondarily determines that the leaf spring meets the pre-fatigue preset standard and issues a pre-fatigue state warning.

8. The fatigue monitoring system for trailer leaf springs according to claim 7, characterized in that: The fatigue determination module determines, based on the limit change gap characteristic value, that the reasons why the leaf spring meets the pre-fatigue preset standard include leaf spring lubrication failure, or leaf spring jacket loosening; when the leaf spring lubrication fails, a leaf spring lubrication failure warning is issued, and when the leaf spring jacket is loose, a leaf spring jacket loose warning is issued.

9. The fatigue monitoring system for trailer leaf springs according to claim 8, characterized in that: In response to the temperature rise limit value of the leaf spring being greater than or equal to a second preset temperature threshold value during the effective fluctuation period, the fatigue determination module corrects the first preset displacement and the second preset displacement by the same amplitude according to the difference between the temperature rise limit value and the second preset temperature threshold value.

10. The fatigue monitoring system for trailer leaf springs according to claim 9, characterized in that: The fatigue determination module is provided with several correction methods for reducing the first preset displacement and the second preset displacement, and each correction method has a different correction amplitude for the first preset displacement and the second preset displacement.

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