Method for testing snow performance of semi-steel radial tire

Abstract

The application discloses a kind of semi-steel radial tire snowfield performance test methods, it is related to tire test technical field, comprising: the test site is preprocessed, and uniform road surface condition is formed;In fixed time period and in the limited road surface environment temperature interval, according to the preset cycle sequence to semi-steel radial tire sample is repeatedly real vehicle test, real vehicle test includes snowfield brake performance test, snowfield acceleration performance test and snowfield handling performance test;The test data of real vehicle test is collected, the standard deviation and the coefficient of variation of test data are calculated, and the coefficient of variation is controlled within the preset threshold value, and the test results under different temperature conditions are averaged, and stable, reproducible semi-steel radial tire snowfield performance test system is realized in natural snow environment.

Description

Technical Field

[0001] This application relates to the field of tire testing technology, and in particular to a test method for the snow performance of semi-steel radial tires. Background Technology

[0002] With the increasing demand for driving safety on icy and snowy roads in winter, semi-steel radial snow tires are widely used in the market. The tire tread pattern and rubber compound directly determine the grip on icy and snowy roads. The industry generally uses natural open-air snow tracks in winter to conduct full-vehicle road tests to verify the comprehensive performance of snow acceleration, snow braking, and snow handling.

[0003] However, open-air natural snow is easily affected by the temperature difference between day and night, ambient temperature, sun exposure and snow melting, and snow compaction. The friction coefficient of icy and snowy roads is unstable. There is a lack of unified, stable and reproducible testing standards for the snow performance of semi-steel radial tires in the industry, and the problem of test fluctuations has existed for a long time. Summary of the Invention

[0004] In view of the above problems, this application provides a testing method for the snow performance of semi-steel radial tires, enabling a stable and reproducible testing system for the snow performance of semi-steel radial tires in natural snow conditions. The specific scheme is as follows: This application provides a method for testing the snow performance of semi-steel radial tires, including: The test site was pre-treated to create uniform road surface conditions; Within a fixed time period and a limited road surface temperature range, the semi-steel radial tire samples were subjected to repeatable real-vehicle tests in a preset cyclic sequence. The real-vehicle tests included snow braking performance tests, snow acceleration performance tests, and snow handling performance tests. Test data from real vehicle tests are collected, and the standard deviation and coefficient of variation are calculated for the test data. The coefficient of variation is controlled within a preset threshold, and the test results under different temperature conditions are averaged.

[0005] This application pre-treats the test site to create uniform road surface conditions, reducing the interference of differences in site topography and snow layer structure on test results from the source. By conducting tests within a fixed time period and a limited road surface temperature range, it effectively avoids fluctuations in the road surface ice and snow adhesion coefficient caused by natural factors such as diurnal temperature differences and solar melting of snow. Repeatable real vehicle tests are conducted according to a preset cyclic sequence, ensuring that each sample is evenly distributed along the test time axis, thus offsetting the temporal environmental deviation caused by sequential testing. Subsequently, the standard deviation and coefficient of variation of the test data are calculated, and the coefficient of variation is controlled within a preset threshold. The test results under different temperature conditions are then averaged to further reduce data fluctuations caused by differences in temperature environment, establishing a universal and reproducible standardized snow performance testing system for semi-steel radial snow tires.

[0006] In some embodiments, each batch of semi-steel radial tire samples is subjected to no less than ten snow braking performance tests and no less than ten snow acceleration performance tests.

[0007] In some embodiments, pretreatment of the test site includes: leveling and compacting the test site foundation, laying a snow surface of uniform thickness relying on natural snowfall, and uniformly compacting the snow layer structure.

[0008] In some embodiments, the fixed time periods include 8:00 to 11:00 and 14:00 to 17:00 daily.

[0009] In some embodiments, the temperature range is defined as -3°C to -18°C.

[0010] In some embodiments, the preset cycle sequence is: a closed-loop reciprocating test sequence of first sample, second sample, third sample, first sample, second sample, and third sample.

[0011] In some embodiments, the preset threshold is 3%.

[0012] In some embodiments, when the calculated coefficient of variation is greater than 3%, the test is repeated under the same test conditions until the coefficient of variation is no greater than 3%.

[0013] In some embodiments, the average value processing of test results under different temperature conditions includes: normalizing the average value of test results of semi-steel radial tire samples of the same specification under different ambient temperatures and different production batches.

[0014] In some embodiments, the method further includes: using an on-board vehicle data acquisition device to record vehicle speed, driving distance, driving time and braking status data to obtain a snow performance score for semi-steel radial tires. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0016] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0017] Figure 1 A flowchart illustrating a method for testing the snow performance of a semi-steel radial tire, as provided in this application embodiment. Detailed Implementation

[0018] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0019] The existing open-air natural snow tire test site is affected by multiple natural environmental factors such as ambient temperature, diurnal temperature difference, natural snowfall, snow compaction degree, and snow melting under sunlight. The snow and ice adhesion coefficient of the snow road surface fluctuates greatly. When conducting semi-steel radial snow tire performance tests at different test time periods and under different ambient temperatures, the test data has a high degree of dispersion and poor comparability between batch test results.

[0020] Existing conventional snow tire testing methods can only control test deviations within a small time period on the same day, and cannot achieve stable reproducibility testing across dates and temperature conditions, resulting in insufficient test accuracy. It is also difficult to accurately distinguish the differences in snow performance brought about by tire tread structure and rubber compound formulation optimization, which seriously restricts the research and development and upgrading of snow grip performance of semi-steel radial snow tires.

[0021] To address the aforementioned issues, this application provides a testing method for the snow performance of semi-steel radial tires, comprising: pre-treating the test site to create uniform road surface conditions; conducting repeatable real-vehicle tests on semi-steel radial tire samples according to a preset cyclic sequence within a fixed time period and a defined road surface temperature range, the real-vehicle tests including snow braking performance tests, snow acceleration performance tests, and snow handling performance tests; collecting test data from the real-vehicle tests, calculating the standard deviation and coefficient of variation of the test data, controlling the coefficient of variation within a preset threshold, and averaging the test results under different temperature conditions. This achieves a stable and reproducible snow performance testing system for semi-steel radial tires in natural snow environments.

[0022] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] This application provides a test method for the snow performance of semi-steel radial tires, such as... Figure 1 As shown, Figure 1 A flowchart illustrating a method for testing the snow performance of a semi-steel radial tire, as provided in this application embodiment.

[0024] like Figure 1 As shown, the preparation method includes the following steps S10 to S30: Step S10: Pre-treat the test site to create uniform road surface conditions; For example, before the annual winter snowfall, the foundation of the selected open-air test site is leveled and compacted to eliminate structural differences such as terrain undulations, potholes, and unevenness. After natural snowfall, a snow layer of uniform thickness is laid on the leveled and compacted foundation, and the snow layer is compacted as a whole to form a test road surface with consistent snow layer thickness, uniform compaction density, and stable ice and snow structure. Through the above site pretreatment, the interference of site terrain differences and snow layer structure inhomogeneity on tire snow test results can be reduced, providing a consistent test road surface condition for subsequent snow performance tests, thereby effectively reducing test errors introduced by differences in site conditions and improving the comparability of test data between different test batches.

[0025] Step S20: Within a fixed time period and a limited road surface ambient temperature range, repeatable real vehicle tests are conducted on the semi-steel radial tire samples according to a preset cyclic sequence. The real vehicle tests include snow braking performance tests, snow acceleration performance tests, and snow handling performance tests. For example, vehicle road tests were conducted during periods of moderate sunlight, from 8:00 to 11:00 and 14:00 to 17:00 daily, avoiding times when the temperature difference between day and night is large, causing fluctuations in the condition of ice and snow, and times when the midday sun is direct, causing snow to melt. Throughout the test cycle, the road surface temperature was kept stable within the range of -3℃ to -18℃, setting temperature boundary conditions for icy and snowy road surfaces.

[0026] The real-vehicle tests include snow braking performance testing, snow acceleration performance testing, and snow handling performance testing. The snow braking performance test is a specific real-vehicle test item for tire snow driving safety performance. After the vehicle is equipped with the snow-specific tires to be tested and completes a start, it is driven at a designated constant speed on a planned, straight, closed snow test surface by a driver with professional tire testing qualifications. Using onboard high-precision driving data acquisition equipment, the braking distance from the start of full braking at the designated speed to a complete stop is recorded, thus evaluating the tire's snow braking grip performance. The snow acceleration performance test is a specific real-vehicle test item for tire snow starting and driving performance. After the vehicle is equipped with the snow-specific tires to be tested and completes a start, it is driven at a designated constant speed on a planned, straight, closed snow test surface by a driver with professional tire testing qualifications. Using onboard high-precision driving data acquisition equipment, the time taken for the vehicle to accelerate from a standstill to the target speed is recorded, thus evaluating the tire's snow starting and driving grip performance. The snow handling performance test is a specific real-vehicle test item for tire snow driving stability limits. After the vehicle is equipped with the snow tires to be tested and starts, it will be tested on a fixed closed-loop snow test track. Professional test drivers will perform extreme control actions such as acceleration, deceleration, emergency braking, and cornering within the tire's driving limits. The vehicle's single-lap driving time will be recorded by onboard high-precision driving data acquisition equipment. Combined with the driver's subjective control experience score, the tire's snow driving stability performance will be comprehensively evaluated.

[0027] By limiting the testing period and ambient temperature range, fluctuations in road grip caused by snow melting and diurnal temperature variations can be significantly reduced, thus mitigating the interference of environmental factors on test results from the source. Simultaneously, employing a closed-loop cyclic testing sequence effectively offsets temporal environmental deviations caused by sequential testing, reducing system test errors. Furthermore, frequent repeated testing reduces the randomness of single tests. These multiple measures collectively reduce data dispersion caused by environmental disturbances, effectively improving the lateral comparability of tire test data across different groups and facilitating accurate identification of actual performance differences resulting from tire compound and tread pattern optimization.

[0028] Step S30: Collect test data from actual vehicle testing, calculate the standard deviation and coefficient of variation of the test data, control the coefficient of variation within a preset threshold, and average the test results under different temperature conditions.

[0029] For example, test data is recorded using an onboard vehicle-mounted data acquisition device, forming multiple sets of raw data samples. Subsequently, statistical analysis is performed on the collected test data, calculating the standard deviation of each set to measure the degree of deviation from the mean, and further calculating the coefficient of variation (COP). This COP, as a dimensionless percentage value, ensures comparability between different types of data such as braking distance and acceleration time. Based on this, the calculated COP is controlled within a preset threshold to ensure high consistency and stability of each set of test data. Finally, the test data from multiple sets under different temperature conditions are averaged.

[0030] By quantitatively calculating the standard deviation and coefficient of variation, the degree of dispersion and fluctuation in test data can be accurately assessed. Preset thresholds can be set to quantitatively constrain test fluctuations from a statistical perspective, ensuring good repeatability and reproducibility of the test data. Furthermore, averaging the test results under different temperature conditions effectively reduces the impact of cross-temperature environmental differences on the test data, minimizing data fluctuations caused by different dates, temperature differences, and temperatures in natural snow conditions. This significantly improves the consistency of snow test results across the entire cycle and batches, providing reliable data support for accurately identifying performance differences in tire tread structure and rubber compound formulations.

[0031] This application pre-treats the test site to create uniform road surface conditions, reducing the interference of differences in site topography and snow layer structure on test results from the source. By conducting tests within a fixed time period and a limited road surface temperature range, it effectively avoids fluctuations in the road surface ice and snow adhesion coefficient caused by natural factors such as diurnal temperature differences and solar melting of snow. Repeatable real vehicle tests are conducted according to a preset cyclic sequence, ensuring that each sample is evenly distributed along the test time axis, thus offsetting the temporal environmental deviation caused by sequential testing. Subsequently, the standard deviation and coefficient of variation of the test data are calculated, and the coefficient of variation is controlled within a preset threshold. The test results under different temperature conditions are then averaged to further reduce data fluctuations caused by differences in temperature environment, establishing a universal and reproducible standardized snow performance testing system for semi-steel radial snow tires.

[0032] In some embodiments, for a single batch of the semi-steel radial tire samples, at least ten snow braking performance tests and at least ten snow acceleration performance tests are conducted.

[0033] Specifically, for the same batch of semi-steel radial tire samples, after completing site pretreatment, controlling the testing period, and limiting the ambient temperature, each tire sample underwent no fewer than ten valid snow braking performance tests and no fewer than ten valid snow acceleration performance tests independently. The snow braking performance test recorded the braking distance of the vehicle from a specified speed to a complete stop under full braking, and the snow acceleration performance test recorded the time taken for the vehicle to accelerate from a standstill to the calibrated target speed.

[0034] By setting up at least ten high-frequency repeated tests per batch, a sufficient sample size can be provided for subsequent calculations of standard deviation and coefficient of variation, making the statistical results more representative and reliable. Multiple repeated tests can effectively offset random errors caused by driver operation randomness or minor differences in local road surfaces in a single test, allowing the test data to more accurately reflect the tire's snow grip performance. This significantly improves the repeatability and reproducibility of snow braking and acceleration performance tests, providing reliable test data to accurately distinguish performance differences between different tire tread patterns and rubber compound formulations.

[0035] In some embodiments, the preset cycle sequence is: a closed-loop reciprocating test sequence of first sample, second sample, third sample, first sample, second sample, and third sample.

[0036] Specifically, under uniform snow conditions, fixed testing periods, and constant temperature, all acceleration, braking, and handling tests for a single set of samples were completed sequentially, following the order of the first, second, and third samples. After the entire set of samples was tested, the test immediately switched back to the first sample to begin a new round of testing, and this cycle was repeated to complete the overall comparative test. Throughout the testing process, the three types of samples were interspersed and rotated to avoid concentrating single samples in the early or late stages of the same day.

[0037] During the test, the natural environment and snow surface conditions will change slowly and subtly over time. Closed-loop rotation testing can evenly distribute the environmental errors caused by the time sequence changes, offset the differences in road conditions caused by the successive tests, avoid the systematic high or low data of a certain tire due to the order of testing, reduce the comparison error between samples, improve the horizontal comparability of test data of different tires, and facilitate accurate differentiation of the real performance differences brought about by different tread patterns and rubber compound formulations.

[0038] In some embodiments, the preset threshold is 3%.

[0039] By setting a coefficient of variation (COP) of 3%, the dispersion and fluctuation of experimental data can be quantitatively constrained. The COP, as a statistical indicator measuring the relative fluctuation of multiple sets of experimental data, indicates better repeatability and greater data stability with a lower value. Controlling the COP below 3% means that the dispersion of the experimental data is compressed to a low level. Differences in results between different test cycles and different samples mainly stem from differences in the tire's structure and compound, rather than noise interference from environmental fluctuations or operational randomness. This ensures good repeatability and reproducibility of the test data, providing a reliable statistical basis for accurately distinguishing differences in snow performance due to tire tread structure and rubber compound formulation. This significantly improves the data credibility and decision-making accuracy in the research and development validation of snow tires.

[0040] In some embodiments, when the calculated coefficient of variation is greater than 3%, the test is repeated under the same test conditions until the coefficient of variation is no greater than 3%.

[0041] By establishing a retesting mechanism for cases where the coefficient of variation exceeds the limit, it is ensured that all test data included in the final evaluation meets the 3% dispersion control requirement, guaranteeing the statistical quality of the test data. If a set of data exhibits excessive dispersion due to accidental driver error, local road anomalies, or other uncontrollable factors, this mechanism allows for retesting under the same conditions to obtain a more reliable data sample, rather than using questionable data for evaluation. This retesting mechanism, in conjunction with the coefficient of variation control threshold, effectively constrains the dispersion of test data, preventing misjudgments of tire performance due to abnormalities in a single test, and further improving the repeatability, reproducibility, and reliability of snow test results.

[0042] In some embodiments, the average value processing of test results under different temperature conditions includes: normalizing the average value of test results of semi-steel radial tire samples of the same specification under different ambient temperatures and different production batches.

[0043] Specifically, after completing the full-process repeated tests under various winter ambient temperatures, test data were collected on semi-steel radial tire samples of the same specification under different road surface ambient temperature conditions, such as -5℃, -10℃, and -15℃, including snow braking distance, snow acceleration time, and snow handling lap time. Simultaneously, performance data was collected for tire samples of the same specification from different production batches during their respective test runs. The test data across temperature conditions and production batches were then compiled and organized. The arithmetic mean of each performance indicator was calculated, and this mean was used as a benchmark. The results of each individual test were then normalized to eliminate dimensional differences and absolute value drift between different temperature ranges and batches, ensuring that all test data are comparable and analyzeable within the same reference system.

[0044] By averaging across temperature conditions, the impact of fluctuations in the adhesion coefficient of icy and snowy roads caused by differences in ambient temperature on test data can be effectively mitigated. In natural snow testing, the road friction characteristics at -5℃ and -15℃ are fundamentally different, and directly comparing the two sets of data can easily lead to misjudgment. By normalizing the test results under each temperature condition to the mean, the data drift caused by the uncontrollable variable of temperature can be eliminated, making the test data obtained at different temperatures comparable. Combined with averaging across production batches, random errors caused by fluctuations in raw materials or differences in processes between batches can be further eliminated, making the final evaluation results more accurately reflect the design performance of the tire product itself. This significantly improves the consistency of snow test results throughout the entire cycle and across batches, providing a reliable data benchmark for the precise benchmarking and optimization of tire tread structure and rubber compound formulation.

[0045] In some embodiments, the testing method further includes: using an on-board vehicle data acquisition device to record vehicle speed, driving distance, driving time and braking status data to obtain a snow performance score for semi-steel radial tires.

[0046] By employing high-precision vehicle-mounted data acquisition equipment to record test parameters, objective quantitative data such as braking distance and acceleration time, accurate to the millisecond or centimeter level, can be obtained, avoiding subjective errors caused by manual timing or visual estimation. The vehicle-mounted equipment can continuously record real-time data throughout the entire test process, providing complete and accurate raw data samples for subsequent standard deviation calculations, coefficient of variation calculations, and mean averaging. Combining the objective data recorded by the vehicle-mounted equipment with the driver's subjective handling experience rating allows for a comprehensive evaluation of tire snow performance from both quantitative and qualitative dimensions, making the snow performance evaluation results more comprehensive, three-dimensional, and reliable.

[0047] Referring to Tables 1 and 2 provides a more intuitive understanding of the testing method of this application. Tables 1 and 2 are divided into two sets of tire acceleration performance test data under different environmental conditions. They record the acceleration time, average value, extreme value, standard deviation, coefficient of variation, and performance score data of three semi-steel radial tire samples (sample 1, sample 2, and sample 3) under different test dates, test periods, environmental conditions, and road surface temperatures. The statistical parameters in the tables clearly demonstrate that after adopting the testing method of this application, the coefficient of variation of the test data for each tire sample is controlled within 3%, directly proving that the testing method of this application can overcome the interference caused by natural temperature and snow surface environment, effectively reduce test dispersion error, and achieve high consistency of test results under different low-temperature conditions, accurately distinguishing the differences in snow performance of different tires.

[0048]

[0049] Table 1

[0050] Table 2

[0051] The various embodiments in this application are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. The embodiments provided in this application can be combined with each other without contradiction.

[0052] It should be noted that, in the description of this application, the accompanying drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. Additionally, for understanding and ease of description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements. Furthermore, "on" means positioning an element on or below another element, but does not inherently mean positioning it above another element according to the direction of gravity.

[0053] The terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the middle.

[0054] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0055] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for testing the snow performance of semi-steel radial tires, characterized in that, include: The test site was pre-treated to create uniform road surface conditions; Within a fixed time period and a limited road surface temperature range, the semi-steel radial tire samples were subjected to repeatable real-vehicle tests in a preset cyclic sequence. The real-vehicle tests included snow braking performance tests, snow acceleration performance tests, and snow handling performance tests. The test data from the actual vehicle test is collected, the standard deviation and coefficient of variation are calculated on the test data, the coefficient of variation is controlled within a preset threshold, and the test results under different temperature conditions are averaged.

2. The test method according to claim 1, characterized in that, For each batch of semi-steel radial tire samples, at least ten snow braking performance tests and at least ten snow acceleration performance tests are conducted.

3. The test method according to claim 1, characterized in that, The pretreatment of the test site includes: leveling and compacting the foundation of the test site, laying a snow surface of uniform thickness relying on natural snowfall, and uniformly compacting the snow layer structure.

4. The test method according to claim 1, characterized in that, The fixed time periods include 8:00 to 11:00 and 14:00 to 17:00 daily.

5. The test method according to claim 1, characterized in that, The defined temperature range is -3℃ to -18℃.

6. The test method according to claim 1, characterized in that, The preset cycle sequence is: a closed-loop reciprocating test sequence of the first sample, the second sample, the third sample, the first sample, the second sample, and the third sample.

7. The test method according to claim 1, characterized in that, The preset threshold is 3%.

8. The test method according to claim 7, characterized in that, If the calculated coefficient of variation is greater than 3%, the test is repeated under the same test conditions until the coefficient of variation is no greater than 3%.

9. The test method according to claim 1, characterized in that, The average value processing of test results under different temperature conditions includes: normalizing the average value of test results of semi-steel radial tire samples of the same specification under different ambient temperatures and different production batches.

10. The test method according to claim 1, characterized in that, The method further includes: using on-board driving data acquisition equipment to record vehicle speed, driving distance, driving time and braking status data, and obtaining the snow performance score of the semi-steel radial tire.

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