Passenger car air spring buckling and pressing parameter test method and test device

Abstract

The invention relates to a method and a device for testing buckling and pressing parameters of an air spring of a passenger car, which belong to the technical field of air springs and comprise the following steps of: providing a bag skin sample sheet and compressing the bag skin sample sheet to a preset compression amount; under the condition that the compression amount is kept constant, obtaining relational data of the compression load of the capsule skin sample piece attenuating along with time, and converting the relational data into contact stress-time relational data; fitting the contact stress-time relation data into a parameterized relaxation model to determine parameters of the model; and substituting the preset life expectancy into the fitted parameterized relaxation model, and calculating to obtain the predicted minimum contact stress at the last phase of the life expectancy. The method can solve the problems that in the prior art, no effective means is provided for accurately measuring the actual contact stress in the buckling process, and particularly, the real-time monitoring of the time evolution process of the contact stress cannot be realized; and the sealing failure risk cannot be controlled.

Description

Technical Field

[0001] This invention belongs to the field of air spring technology, and specifically relates to a test method and test device for the compression parameters of air springs in passenger vehicles. Background Technology

[0002] With the development of the new energy vehicle industry and the localization of key components, air suspension is being used more and more widely in new energy vehicles. Unlike traditional suspension, air suspension uses air springs as elastic elements. By adjusting the pressure and volume of the compressed air inside, it can actively adjust the vehicle height and significantly improve the ride smoothness and ride comfort.

[0003] Air springs typically operate under high pressure environments ranging from 0.8 MPa to 1.0 MPa, and their sealing performance directly affects the reliability and safety of the system. To ensure long-term stable operation, all connection points of the air spring must possess excellent airtightness and tensile strength. The bladder, as a key pressure-bearing module of the air spring, is usually composed of a composite of rubber and reinforcing cord. Its upper and lower ends are sealed to metal components such as pistons or top seats through a crimping process. The crimping process generally uses a multi-lobed (e.g., 8-lobed or 12-lobed) crimping die to apply uniform radial pressure to the annular crimping component, causing it to undergo plastic shrinkage deformation. This creates an interference fit between the crimping ring, the bladder, and the crimped component, achieving sealing and axial locking. However, since the bladder is mainly composed of rubber, it exhibits significant viscoelasticity and stress relaxation characteristics. Under long-term compression, its internal stress gradually decreases over time, leading to a decrease in contact pressure in the crimping area and weakening the friction between the interfaces. When the frictional force decreases to an insufficient level to resist the axial pull-out force generated by the internal air pressure of the air spring, the bladder skin may experience slight slippage or loosening, ultimately leading to seal failure and gas leakage. Furthermore, because the crimping structure is annularly symmetrical and the crimping process relies on the coordinated action of multiple mold segments, it is difficult to accurately measure the contact stress within the crimping area, especially making it difficult to monitor the evolution of contact stress over time in real time, thus failing to control the risk of seal failure. Summary of the Invention

[0004] To address the shortcomings of existing technologies, a test method and apparatus for testing the buckling parameters of air springs in passenger vehicles are proposed. This method aims to solve the problem that existing technologies lack effective means to accurately measure the actual contact stress during the buckling process, and in particular, cannot achieve real-time monitoring of the evolution of contact stress over time, which leads to an inability to control the risk of seal failure.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for testing the compression parameters of air springs in passenger vehicles, comprising the following steps: S100, Provide a sample of the capsule skin and compress it to a predetermined amount of compression; S200. While keeping the compression constant, obtain the relationship data of the compressive load of the bladder sample as a function of time, and convert the relationship data into contact stress-time relationship data. S300. Fit the contact stress-time relationship data to a parameterized relaxation model to determine the parameters of the model. The parameterized relaxation model is used to characterize the stress relaxation characteristics of the skin sample. S400. Substitute the preset expected lifespan into the fitted parameterized relaxation model to calculate the predicted minimum contact stress at the end of the expected lifespan.

[0006] The technical solution is further configured such that, in step S100, the material of the bladder sample is the same as the material of the air spring bladder to be predicted.

[0007] The technical solution is further configured such that, in step S100, the bladder sample is placed in a testing device, and pressure is applied to it by the testing device to make it reach a predetermined compression amount, wherein the predetermined compression amount is determined based on the design parameters of the air spring product to be predicted.

[0008] The technical solution is further configured such that, in step S200, the compressive load of the bladder sample is measured in real time by the force measurement module integrated in the test device, and the compressive load value obtained by the force measurement module is continuously read by the data acquisition module of the test device at a set time frequency, and is matched with the current timestamp to obtain the relationship data of the compressive load decaying over time.

[0009] This technical solution is further configured to convert each compressive load value in the data on the relationship between the compressive load and time decay into a contact stress value based on the contact area between the bladder sample and the pressure module in the test device, so as to generate contact stress-time relationship data.

[0010] This technical solution is further configured such that, in step S300, based on the contact stress-time relationship data, a nonlinear curve is fitted using a Prony series model to obtain the fitting parameters. The expression for the Prony series model is: ,in, for Contact stress at any moment To balance the stress, Let be the coefficient of the i-th relaxation term. For the first The relaxation time of the relaxation term. The number of relaxation terms. It is a natural number that is not less than 2.

[0011] This technical solution is further configured such that, in step S400, the preset expected lifespan time is substituted into the fitted Prony series model to calculate the predicted minimum contact stress at the end of the expected lifespan. .

[0012] This technical solution is further configured such that, after step S400, the calculated predicted minimum contact stress is further included. Minimum critical contact stress required for a pre-set seal Compare; like ≥ If so, it is determined that the current compression amount design meets the sealing requirements within the expected lifespan; like < If the current compression design does not meet the sealing requirements within the expected lifespan, the compression amount needs to be adjusted, and steps S100 to S400 are repeated until the requirements are met. ≥ .

[0013] This technical solution is further configured such that, before step S100, it also includes: S00. Perform steps S100 to S200 at at least two different test temperatures to obtain contact stress-time relationship data at different test temperatures. In step S300, based on the contact stress-time relationship data obtained at different test temperatures, the contact stress-time master curve at the reference temperature is constructed by applying the time-temperature equivalence principle, and the master curve is used as the fitting object.

[0014] Secondly, the present invention provides a passenger vehicle air spring clamping parameter testing device, comprising: The pressure module is used to compress the capsule sample to a predetermined amount of compression. A force measurement module is used to detect the compressive load on the cystic membrane sample. The data acquisition module is used to record the change data of the compressive load over time; The system also includes a data processing module for converting the compressive load decay data over time into contact stress-time relationship data, fitting the contact stress-time relationship data to a parameterized relaxation model, and substituting the preset expected lifespan into the fitted parameterized relaxation model to calculate the predicted minimum contact stress at the end of the expected lifespan.

[0015] The beneficial effects of this invention are: 1. By measuring the change of contact stress in the compression area of ​​passenger car air springs over time, the amount of contact stress change within the expected lifespan can be predicted and compared with the minimum critical contact stress required to ensure air spring sealing. This allows for a more reasonable determination of air spring clamping parameters and reduces the failure rate of air springs due to stress relaxation.

[0016] 2. By testing the changes in the contact stress of the bladder at different test temperatures, and through the time-temperature equivalence relationship, the sealing performance in different climatic regions can be predicted, thereby enhancing the product's environmental adaptability. Attached Figure Description

[0017] Figure 1 This is a flowchart of the passenger vehicle air spring compression parameter test method in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the relationship between contact stress and time in an embodiment of the present invention; Figure 3 This is a schematic diagram of the passenger vehicle air spring clamping parameter testing device in an embodiment of the present invention; Figure 4 This is an assembly diagram of the pressure application module and the support module in an embodiment of the present invention; Figure 5 This is a schematic diagram of the pressure application module in an embodiment of the present invention; Figure 6 This is a schematic diagram of the support module in an embodiment of the present invention; In the attached diagram: 100, pressure application module; 101, pressure application working module; 102, pressure application guide module; 103, pressure application limiting pin; 104, pressure application threaded section; 105, pressure application fixing nut; 106, pressure application limiting hole; 200, support module; 201, support working module; 202, support guide module; 203, support limiting pin; 204, support threaded section; 205, support fixing nut; 206, support limiting hole; 207, groove; 300, tensile testing machine; 301, upper interface; 302, lower interface; 400, bladder skin sample. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0019] Current designs for air spring clamping parameters in passenger vehicles do not consider the impact of rubber stress relaxation. Stress relaxation leads to reduced contact stress in the clamping area of ​​the air spring bladder, resulting in decreased friction during air spring operation and increased risk of leakage. Therefore, this invention designs a testing method and apparatus for passenger vehicle air spring clamping parameters. This method predicts the minimum contact stress of the air spring bladder in the clamping area within its expected lifespan and compares it with the minimum critical contact stress required for air spring sealing, thereby guiding the setting of reasonable clamping parameters.

[0020] Example 1: According to an embodiment of the present invention, a test method for the buckling parameters of air springs in passenger vehicles is provided. Please refer to [link / reference]. Figure 1 This includes the following steps: S100. Provide a sample of the air spring and compress it to a predetermined compression amount, which is preset by the operator according to the design parameters of the air spring product to be predicted.

[0021] S200. While keeping the compression constant, obtain the relationship data of the compressive load of the bladder sample decaying over time, and convert the relationship data into contact stress-time relationship data.

[0022] S300. Fit the contact stress-time relationship data to a parameterized relaxation model to determine the parameters of the model. The parameterized relaxation model is used to characterize the stress relaxation characteristics of the skin sample.

[0023] S400. Substitute the preset expected lifespan into the fitted parameterized relaxation model to calculate the predicted minimum contact stress at the end of the expected lifespan.

[0024] Understandably, load attenuation tests under constant compression accurately reflect the stress relaxation behavior of the bladder skin under simulated buckling conditions, filling the gap in existing technologies that cannot measure the change of contact stress in the buckling area over time. Extrapolating short-term test data to the expected lifespan (typically 6-8 years) through a parametric relaxation model significantly shortens the R&D cycle, reduces testing costs, and enhances design foresight.

[0025] In this embodiment, a method for testing the compression parameters of an air spring in a passenger vehicle, in step S100, the material of the spring skin sample is the same as the material of the air spring spring skin to be predicted. Material consistency is a prerequisite for ensuring the validity of the test extrapolation, enabling the test data to truly reflect the performance of the target product and avoiding misjudgments due to material deviations.

[0026] Optionally, the bladder sample is placed in a testing apparatus, and pressure is applied to it to achieve a predetermined compression. The predetermined compression is determined based on the design parameters of the air spring product to be predicted, ensuring that the stress state of the bladder sample closely approximates the stress distribution of the actual clamping area. Linking the compression to the actual product design allows the test results to be directly used to guide the setting of process parameters.

[0027] In a passenger vehicle air spring compression parameter test method of this embodiment, in step S200, the compressive load of the bladder sample is measured in real time by the force measurement module integrated in the test device. The data acquisition module of the test device continuously reads the compressive load value obtained by the force measurement module at a set time frequency and corresponds it with the current timestamp to obtain the relationship data of compressive load decay over time, which intuitively reflects the dynamic process of stress relaxation of the bladder material.

[0028] Understandably, once the predetermined compression is reached, the testing apparatus locks the displacement, maintaining a constant compression of the capsule sample throughout the subsequent test. Under this constant strain condition, the stress within the capsule material gradually decreases over time; this phenomenon is known as "stress relaxation." Corresponding to this internal stress attenuation, the compressive load applied to the capsule sample also decreases. The force measurement module within the apparatus continuously monitors and records the compressive load, while the data acquisition module captures the entire compressive load attenuation process at high frequency and automatically, providing a high-quality data foundation for subsequent model fitting.

[0029] Optionally, each compressive load value in the data on the relationship between compressive load decay over time can be converted into a contact stress value based on the contact area between the bladder sample and the pressure application module in the testing device, to generate contact stress-time relationship data, i.e., a stress relaxation curve. Please refer to [link to relevant documentation]. Figure 2 .

[0030] Specifically, the conversion formula between compressive load and contact stress is as follows: ,in For contact stress, For compressive load, This represents the area of ​​the compressed region of the cystic tissue sample.

[0031] It should be noted that multiple capsule skin samples prepared using the same batch of materials were tested under the exact same compression. If the stress relaxation curves obtained from multiple tests highly overlap, it indicates that the test method is stable and the results are reliable. The operator can choose the most representative curve for fitting, or use the average results of several curves to build a more robust model. If the results are highly discrete, it suggests that there may be a problem with the test process or sample preparation, which needs to be investigated.

[0032] In a passenger vehicle air spring clamping parameter test method of this embodiment, in step S300, based on the contact stress-time relationship data, a nonlinear curve is fitted using a Prony series model to obtain the fitting parameters. The expression of the Prony series model is: ,in, for Contact stress at any moment This refers to the equilibrium stress after the relaxation process ends (the stress theoretically occurring over an infinitely long time). Let be the coefficient of the i-th relaxation term. For the first The relaxation time of the relaxation term. The number of relaxation terms. The number of relaxation terms is a natural number not less than 2. The more terms there are, the more refined the model.

[0033] The Prony series model described above was fitted to the experimentally measured contact stress-time data using mathematical software (such as Matlab, Origin, etc.). The software automatically adjusted the parameters in the model using optimization algorithms (such as least squares method). , , This minimizes the error between the curve calculated by the Prony series and the experimental data points. Specifically, it is for... , , Parameters such as these are used to set initial guess values ​​to help the fitting algorithm converge faster and more stably. For example, The initial value can be set as the stress value at the end of the curve. It can be set as several representative time points on the timeline.

[0034] Understandably, the stress relaxation behavior of polymeric materials (such as rubber casings) can often be approximated by a sum of a series of decaying exponential functions. The Prony series is precisely this type of mathematical model, widely used in viscoelasticity, with clear physical meaning and high fitting accuracy. In other words, the Prony series can fit multiple relaxation processes, more realistically reflecting the viscoelastic response of rubber.

[0035] In a passenger vehicle air spring clamping parameter test method of this embodiment, in step S400, the preset expected lifespan time is substituted into the fitted Prony series model to calculate the predicted minimum contact stress at the end of the expected lifespan. .

[0036] Specifically, the target time Substituting the (expected life) into the established Prony series formula, the predicted contact stress value at that moment can be directly calculated. : .

[0037] In this embodiment of the passenger car air spring clamping parameter test method, after step S400, the method further includes applying the calculated predicted minimum contact stress. Minimum critical contact stress required for a pre-set seal Compare; like ≥ If the current compression amount design meets the sealing requirements within the expected lifespan, the crimping parameters (crimping amount, i.e., compression amount) are sufficient to ensure that the product will not experience sealing failure throughout its entire lifespan, and the design is safe and reliable. like < If the current compression design does not meet the sealing requirements within the expected lifespan, the compression amount needs to be adjusted, and steps S100 to S400 are repeated until the requirements are met. ≥ .

[0038] By employing the above technical solution, a complete closed loop of "experimentation → modeling → prediction → verification → optimization" is constructed, enabling iterative optimization of the crimping parameters. The minimum critical contact stress required for sealing is introduced, and the predicted minimum contact stress at the end of the expected lifespan is compared with it. Instead of relying on trial and error based on experience, a reasonable crimping amount is determined based on physical mechanisms and data-driven methods, improving the design success rate, avoiding over-design or under-design, fundamentally reducing long-term air leakage problems caused by stress relaxation, and extending the service life of the air spring.

[0039] In this embodiment, a method for testing the compression parameters of an air spring in a passenger vehicle further includes, before step S100: S00. Perform steps S100 to S200 at at least two different test temperatures to obtain contact stress-time relationship data at different test temperatures. In step S300, based on the contact stress-time relationship data obtained at different test temperatures, the time-temperature equivalence principle (such as the WLF equation) is applied to construct the contact stress-time master curve at the reference temperature, and the master curve is used as the fitting object.

[0040] Understandably, accelerating the relaxation process at high temperatures and extrapolating room temperature performance through translation factors can achieve an "accelerated aging" effect, predict sealing performance in different climate regions (such as the severe cold of Northeast China and the high temperature of Hainan), and enhance the product's environmental adaptability.

[0041] Example 2: According to an embodiment of the present invention, a test device for the buckling parameters of air springs in passenger vehicles is provided. Please refer to [link / reference]. Figures 3 to 6 ,include: The pressure module 100 is used to compress the capsule sample 400 to a predetermined compression amount; A force measurement module is used to detect the compressive load on the bladder skin sample 400; The data acquisition module is used to record the change data of the compressive load over time; The system also includes a data processing module for converting the compressive load decay data over time into contact stress-time relationship data, fitting the contact stress-time relationship data to a parameterized relaxation model, and substituting the preset expected lifespan into the fitted parameterized relaxation model to calculate the predicted minimum contact stress at the end of the expected lifespan.

[0042] Optionally, it also includes a support module 200, a pressure module 100, and the support module 200 being arranged opposite to each other. The pressure module 100 and the support module 200 are respectively connected to the upper interface 301 and the lower interface 302 of the tensile testing machine 300. The pressure application module 100 includes a pressure application working module 101 for simulating a clamping ring, and the support module 200 includes a support working module 201 for simulating a clamped part. The bladder skin sample 400 is located above the support working module 201. The tensile testing machine 300 controls the pressure application working module 101 to move downward to compress the bladder skin sample 400.

[0043] By adopting the above technical solution, a spring skin sample 400 is used to replace the entire spring skin for testing. A pressure application module 100 and a support module 200 are designed and connected to a tensile testing machine 300. The tensile testing machine 300 controls the downward movement of the pressure application module 101, causing it to compress the spring skin sample 400 to a predetermined compression amount. Maintaining this compression amount, the tensile testing machine 300's built-in force measurement module (force sensor) records the compression load. A data acquisition module records the change in the compression load over time. A data processing module converts the compression load into contact stress, enabling the equivalent measurement of the change in contact stress over time in the crimping area of ​​the passenger car air spring spring skin. This solves the problem of difficulty in measuring the contact stress in the crimping area of ​​the air spring spring skin in existing technologies.

[0044] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The pressure application module 101 is elongated, with its width being the same as the width of the contact surface between the clamping ring and the bladder skin during the actual clamping process, and its length being the circumference of the bladder skin. to .

[0045] By adopting the above technical solution, the design of the pressure application module 101 enables it to accurately simulate the pressure distribution of the actual clamping ring on the bladder skin, ensuring the accuracy and reliability of the test results.

[0046] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The pressure application module 100 also includes a pressure guide module 102, the cross-sectional shape of which is the same as that of the upper interface 301 of the tensile testing machine, and the two are fitted with a clearance fit. This design allows the pressure application module 100 to be stably installed on the tensile testing machine 300, avoiding displacement or shaking during the test and improving test accuracy.

[0047] Optionally, the upper interface 301 is designed to be circular, and the corresponding pressure guiding module 102 is designed to be cylindrical, which is embedded inside the upper interface 301, that is, the two are fitted with a clearance to ensure that the concentricity of the pressure module 100 and the upper interface 301 of the tensile testing machine meets the requirements.

[0048] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The pressure guiding module 102 is provided with a pressure limiting hole 106, and a pressure limiting pin 103 is connected between the pressure limiting hole 106 and the upper connecting hole at the upper interface 301.

[0049] By adopting the above technical solution, the setting of the pressure limiting pin 103 can prevent the pressure guiding module 102 from rotating or displacing during the test, ensuring that the pressure working module 101 always stays in the correct position and applies uniform pressure to the bladder sample 400.

[0050] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 One end of the pressure guiding module 102 is connected to the pressure working module 101, and a pressure thread section 104 is provided at the connection between the two. A pressure fixing nut 105 adapted to the thread is provided on the pressure thread section 104.

[0051] During assembly, the pressure limiting pin 103 passes sequentially through the upper connecting hole and the pressure limiting hole 106 to restrict the axial movement of the pressure module 100. Then, the pressure fixing nut 105 is rotated until its end face abuts against the edge of the upper interface 301. By applying sufficient tightening torque, the pressure fixing nut 105 locks the pressure module 100 onto the tensile testing machine 300, eliminating any possible risk of slippage. By loosening and tightening the pressure fixing nut 105, the entire pressure module 100 can be quickly installed onto or removed from the tensile testing machine 300. This is very convenient for replacing pressure modules 100 of different specifications to meet the testing needs of different models of air spring bladders.

[0052] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The support working module 201 is provided with a groove 207 for placing the bladder skin sample 400. The bottom surface of the groove 207 has raised patterns. The raised patterns are designed to simulate the shape of components such as the piston and top seat of the air spring assembly (the clamped parts) in the clamping area, thereby more closely simulating the stress state of the bladder skin in the clamping area. By changing the raised pattern structure, the influence of different raised patterns on the clamping performance can be verified.

[0053] The width of the groove 207 is the same as the width of the contact surface between the clipped part and the bladder skin during the actual clipping process, and the length of the groove 207 is greater than the length of the pressure application module 101. This size design ensures that the bladder skin sample 400 can be completely placed in the groove 207, and that the pressure application module 101 can completely cover the test area of ​​the bladder skin sample 400.

[0054] Optionally, the length difference between the groove 207 and the pressure working module 101 is 0.2 mm.

[0055] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The groove 207 has three sidewalls that abut against the cystic membrane sample 400. The design of the three sidewalls forms a U-shaped structure, which can effectively prevent the cystic membrane sample 400 from being excessively deformed during testing, more realistically simulating the snapping state of the cystic membrane, and also making it easier for operators to place and remove the cystic membrane sample 400, thus improving testing efficiency. Optionally, the depth of the groove 207 is slightly greater than the thickness of the bladder skin sample 400, and the length of the bladder skin sample 400 is less than the length of the pressure working module 101, with the length difference between the two preferably being 0.1 mm.

[0056] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6The support module 200 further includes a support guide module 202, the structure of which is the same as that of the pressure guide module 102.

[0057] Specifically, the cross-sectional shape of the support guide module 202 is the same as that of the lower interface 302 of the tensile testing machine, and the two are fitted with a clearance fit. This design allows the support module 200 to be stably installed on the tensile testing machine 300, avoiding displacement or shaking during testing and improving testing accuracy. Optionally, the lower interface 302 is designed to be circular, and correspondingly, the support guide module 202 is designed to be cylindrical, embedded inside the lower interface 302, i.e., the two are fitted with a clearance fit, ensuring that the concentricity of the support module 200 and the lower interface 302 meets the requirements. The support guide module 202 is provided with a support limiting hole 206, and a support limiting pin 203 connects the support limiting hole 206 and the lower connecting hole at the lower interface 302. The support limiting pin 203 can prevent the support guide module 202 from rotating or displacing during testing.

[0058] In the passenger car air spring buckling parameter testing device of this embodiment, please refer to... Figures 3 to 6 The support guide module 202 and the support working module 201 are provided with a support thread section 204, and a support fixing nut 205 adapted to its thread is provided on the support thread section 204.

[0059] During assembly, the support limiting pin 203 passes sequentially through the lower connecting hole and the support limiting hole 206, restricting the axial movement of the support module 200. Then, the support fixing nut 205 is rotated until its end face abuts against the edge of the lower interface 302. By applying sufficient tightening torque, the support fixing nut 205 locks the support module 200 onto the tensile testing machine 300, eliminating any possible risk of slippage. By loosening and tightening the support fixing nut 205, the entire support module 200 can be quickly installed onto or removed from the tensile testing machine 300. This is very convenient for replacing support modules 200 of different specifications to meet the testing requirements of different models of air spring bladders.

[0060] During the test, the air spring bladder sample 400 is placed in the groove 207 of the support module 201. The tensile testing machine 300 is started, and the pressure application module 101 is moved downward to compress the air spring bladder sample 400, simulating the actual crimping process. Keeping the compression constant, the relationship between the compression load and time is obtained. The compression load is then converted into contact stress, which can be used to equivalently measure the change in contact stress over time in the crimping area of ​​the passenger car air spring bladder. Using the fitted parametric relaxation model, the change in contact stress over the expected lifespan can be predicted and compared with the minimum critical contact stress required to ensure the air spring seal. This allows for a more reasonable determination of the air spring crimping parameters, reducing the failure rate of air spring leakage due to stress relaxation. This testing device is simple in structure and easy to operate, accurately simulating the air spring bladder crimping process and providing reliable test data for the design and quality control of passenger car air springs.

[0061] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0062] Optionally, specific examples in this embodiment can refer to the examples described in the above embodiments, and will not be repeated here.

[0063] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0064] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0065] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A test method for the buckling parameters of air springs in passenger vehicles, characterized in that, Includes the following steps: S100, Provide a sample of the capsule skin and compress it to a predetermined amount of compression; S200. While keeping the compression constant, obtain the relationship data of the compressive load of the bladder sample as a function of time, and convert the relationship data into contact stress-time relationship data. S300. Fit the contact stress-time relationship data to a parameterized relaxation model to determine the parameters of the model. The parameterized relaxation model is used to characterize the stress relaxation characteristics of the skin sample. S400. Substitute the preset expected life into the fitted parametric relaxation model to calculate the predicted minimum contact stress at the end of the expected life.

2. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 1, characterized in that, In step S100, the material of the bladder sample is the same as the material of the air spring bladder to be predicted.

3. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 1, characterized in that, In step S100, the bladder sample is placed in a testing device, and pressure is applied to it by the testing device to achieve a predetermined compression amount, which is determined based on the design parameters of the air spring product to be predicted.

4. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 3, characterized in that, In step S200, the compressive load of the bladder sample is measured in real time by the force measurement module integrated in the test device. The data acquisition module of the test device continuously reads the compressive load value obtained by the force measurement module at a set time frequency and matches it with the current timestamp to obtain the relationship data of the compressive load decay over time.

5. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 4, characterized in that, Each compressive load value in the data on the relationship between the compressive load and time decay is converted into a contact stress value based on the contact area between the bladder skin sample and the pressure module in the test device, so as to generate contact stress-time relationship data.

6. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 1, characterized in that, In step S300, based on the contact stress-time relationship data, nonlinear curve fitting is performed using a Prony series model to obtain fitting parameters.

7. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 6, characterized in that, In step S400, the preset expected lifespan is substituted into the fitted Prony series model to calculate the predicted minimum contact stress at the end of the expected lifespan. .

8. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 7, characterized in that, Following step S400, the method further includes applying the calculated predicted minimum contact stress. Minimum critical contact stress required for a pre-set seal Compare; like ≥ If so, it is determined that the current compression amount design meets the sealing requirements within the expected lifespan; like < If the current compression design does not meet the sealing requirements within the expected lifespan, the compression amount needs to be adjusted, and steps S100 to S400 are repeated until the requirements are met. ≥ .

9. The method for testing the compression parameters of an air spring in a passenger vehicle according to claim 1, characterized in that, Before step S100, the method further includes: S00. Perform steps S100 to S200 at at least two different test temperatures to obtain contact stress-time relationship data at different test temperatures. In step S300, based on the contact stress-time relationship data obtained at different test temperatures, the contact stress-time master curve at the reference temperature is constructed by applying the time-temperature equivalence principle, and the master curve is used as the fitting object.

10. A test apparatus for implementing the passenger vehicle air spring buckling parameter test method according to any one of claims 1-9, characterized in that, include: The pressure module is used to compress the capsule sample to a predetermined amount of compression. A force measurement module is used to detect the compressive load on the cystic membrane sample. The data acquisition module is used to record the change data of the compressive load over time; The system also includes a data processing module for converting the compressive load decay data over time into contact stress-time relationship data, fitting the contact stress-time relationship data to a parameterized relaxation model, and substituting the preset expected lifespan into the fitted parameterized relaxation model to calculate the predicted minimum contact stress at the end of the expected lifespan.

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