A method, apparatus and computer program product for indoor impact testing of an automotive tire

Abstract

The present application relates to the technical field of tire performance testing, and particularly relates to a method, equipment and computer program product for indoor impact test of automobile tire. The method installs an impact strip on a rotating drum of a tire high-speed uniformity test machine, tests impact force and attenuation performance by using the impact strip, and evaluates impact resistance performance of a tire by using a coefficient of variation C.V of a peak-to-peak value RFpp or TFpp, so as to facilitate selection of a tire scheme and correlation research with a real vehicle comfort test result.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of performance testing of tires, and in particular to a method, device and computer program product for indoor impact testing of automobile tires. BACKGROUND

[0002] When a tire passes through an irregular road, a rough road, and a road with obstacles, the tire is deformed by the impact of the obstacle at the moment of contact between the tire and the obstacle, and the rim is subjected to an action force through the contact part of the tire bead with the rim. The tire has certain containment characteristics, and part of the obstacle will be contained in the tire. The vertical force of the tire directly affects the ride comfort of the vehicle, and the study of its mechanical properties is crucial to the overall comfort of the vehicle.

[0003] For the evaluation of tire impact performance, it is generally dependent on the subjective evaluation results of the ride comfort of the vehicle. The wheel impact test of the vehicle is extremely easy to cause injury to the test personnel and test equipment under high-speed conditions. At the same time, the subjective evaluation process is influenced by the subjective personal preference factors of the evaluation engineer, and the vehicle test is expensive. In order to evaluate the tire impact performance before the subjective evaluation process in order to carry out tire development work, shorten the development cycle, and save development costs, it is necessary to accurately and objectively evaluate the tire impact performance without subjective evaluation.

[0004] Chinese patent application (publication number: CN115452300A, publication date: 2022-12-09) discloses a test method for dynamic impact testing of tires, comprising the following steps: test preparation: installing the tire rim assembly on the test equipment, the test equipment includes a load wheel, the surface of the load wheel is provided with an excitation object, the tire is loaded with a load and is in contact with the surface of the load wheel; t times of impact testing: t test points are taken at equal intervals along the circumferential surface of the tire, the t test points divide the circumference of the tire into t equal parts, the load wheel drives the tire to rotate and makes each test point on the tire pass through the excitation object at a test speed, and the fluctuation of the force in each direction of the tire during the passing of each test point through the excitation object is recorded; wherein t is a common multiple of 2 and 3 or a common multiple of 2, 3 and 4; the average value of the results of t times of impact testing is taken as the subsequent analysis. The method needs to design the test equipment, and only the test method is given, but the method of data analysis and evaluation is not given.

[0005] The tire high-speed uniformity tester adopted in the present application is a physical performance testing instrument used in the field of chemical engineering, which is used for testing the radial force, lateral force, tangential force fluctuation, bounce, flat point, obstacle and balance of the tire at high speed. SUMMARY

[0006] In order to solve the above technical problems, the purpose of the present application is to provide an indoor impact test method for automobile tires, which tests the impact force and attenuation performance by installing an impact strip on the rotating drum of a tire high-speed uniformity testing machine, evaluates the impact resistance performance of a tire by using the coefficient of variation C·V of the peak-to-peak value RFpp or TFpp, facilitates the selection of tire schemes, and facilitates the correlation study with real vehicle comfort test results.

[0007] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0008] An indoor impact test method for automobile tires, which adopts a tire high-speed uniformity testing machine, installs an impact strip on the rotating drum of the tire high-speed uniformity testing machine at 0 degrees in the transverse direction; the method comprises the following steps:

[0009] 1) The tire is loaded and run on the tire high-speed uniformity testing machine for impact test, and the impact data including the radial force RF, the tangential force TF, and the lateral force LF are obtained;

[0010] 2) The RF, TF, and LF data collected under each working condition of the impact test are classified into different data sets, the data of each data set is taken as the vertical coordinate, and the time is taken as the horizontal coordinate to plot, and then fitting is performed to obtain the average force values RFavg, TFavg, and LFavg in three directions vs. time graphs;

[0011] 3) The data in the RF and TF directions are selected for analysis, and the peak-to-peak values RFpp and TFpp are obtained after processing and analyzing the RFavg vs. Time and TFavg vs. Time data; the peak-to-peak value is the difference between the maximum value and the minimum value of the measured signal within a specified frequency bandwidth, i.e. the size of the force of the tire passing over the protrusion; RFpp is the size of the radial force RF of the tire at the initial time of passing over the protrusion, and the smaller the RFpp, the smaller the initial radial impact force of the tire; TFpp is the size of the tangential force TF of the tire at the initial time of passing over the protrusion;

[0012] 4) The ratio of the standard deviation to the average is called the coefficient of variation, denoted as C·V, and for the tire impact resistance performance evaluation of tires of the same specification and different schemes, when the coefficient of variation C·V of the RFpp or TFpp value is greater than or equal to 2.5%, it is determined that the radial or tangential impact resistance performance of the tire has obvious difference, otherwise when C·V is less than 2.5%, the radial or tangential impact resistance performance of the tire has no obvious difference.

[0013] Preferably, the cross section of the impact strip is square.

[0014] As preferred, the method further comprises selecting a rim meeting the standard requirements and mounting the tire onto the rim, and placing the tire in a test chamber at an ambient temperature of 25±3℃ for at least 3 hours.

[0015] As preferred, the method further comprises mounting the tire and rim assembly onto the testing machine, and adjusting the air pressure to the test air pressure, setting the test speed, and the load.

[0016] As preferred, the test conditions are as follows:

[0017] For passenger car tires: the test air pressure is 220 kPa; the test load is 80% of the maximum load capacity; and the test speed is 30-60 km / h.

[0018] For light truck tires: the test air pressure is 350 kPa; the test load is 70% of the maximum load capacity; and the test speed is 30-60 km / h.

[0019] As preferred, the method further comprises, after the test, performing an appearance inspection of the tire, and the appearance inspection should not have defects such as delamination of the tread, sidewall, ply, belt, breaker, and bead, ply crack, cord separation, cord breakage, chunking, joint separation, alligatoring, and abnormal deformation of the carcass, and if the above defects exist, the defects should be noted in the report, and a new tire should be prepared for retesting.

[0020] Further, the present application also discloses an indoor impact test device for automobile tires, which comprises a tire high-speed uniformity testing machine, a data acquisition module, and a calculation module.

[0021] The data acquisition module is used for acquiring impact data of the tire when the tire is loaded and run on the tire high-speed uniformity testing machine, and the impact data comprises radial force RF, tangential force TF, and lateral force LF.

[0022] The calculation module is used for executing steps 2) to 4) in the method.

[0023] Further, the present application also discloses a computer device comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to realize steps 2) to 4) in the method.

[0024] Further, the present application also discloses a computer readable storage medium, which stores a computer program or instructions, and the computer program or instructions are executed by a processor to realize steps 2) to 4) in the method.

[0025] Further, the application also discloses a computer program product comprising a computer program or instructions which, when executed by a processor, implement steps 2) to 4) in the method.

[0026] The application adopts the technical scheme, the method tests the impact force and the attenuation performance by installing the impact strip on the drum of the tire high-speed uniformity tester, evaluates the impact resistance of a tire by using the coefficient of variation C·V of the peak-to-peak value RFpp or TFpp, is convenient for tire scheme selection, and is convenient for correlation research with real vehicle comfort test results. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic view of the device of the application, wherein 1 is a drum, 2 is an impact strip, 3 is a tire, and 4 is a rim.

[0028] Figure 2 It is a schematic view of the impact strip.

[0029] Figure 3 It is a schematic view of the tire impact test RF vs. Time test.

[0030] Figure 4 It is a schematic view of the tire impact test TF vs. Time test. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the application.

[0032] An indoor impact test method for a tire of a vehicle, comprising the following steps:

[0033] 1) Tire installation and parking: a rim meeting the standard requirements is installed on the tire of a vehicle, and the tire is parked at an ambient temperature (25±3℃) in a test room for at least 3 hours;

[0034] 2) Impact strip installation: a 15mm (high) x 25mm (wide) right-angle impact strip (attached Figure 1 ) and a matching weight are installed on the drum at the correct position; the impact strip is installed horizontally at 0 degrees;

[0035] 3) Installation of the tire and rim combination: the tire and rim combination is installed on the tester, and the air pressure is adjusted to the test air pressure. The test speed and load are set.

[0036] 4) Impact test: The tire is run at a certain speed in the CW (clockwise) direction, and the tire is warmed up for 1 min. According to Table 1, the tire is loaded and run, and data is collected. A total of 16 impact data is collected, including radial force RF, tangential force TF, lateral force LF, etc.

[0037] Table 1 Impact test conditions

[0038] Tire type Test air pressure (closed, kPa) Test load (kg) Test speed (km / h) Passenger car tire 220 Maximum load capacity x 80% 30-60 Light truck tire 350 Single tire maximum load capacity x 70% 30-60

[0039] 5) Tire appearance inspection: After the test, the tire appearance is inspected. The appearance inspection should not have (tread, sidewall, cord layer, belt layer or buffer layer, bead) delamination, cord layer crack, cord stripping, cord fracture, chipping, joint cracking, cracking, and abnormal deformation of the carcass, etc. If the above defects exist, they need to be noted in the report, and a new tire needs to be prepared for retesting.

[0040] 6) Data classification processing and evaluation

[0041] The 16 cycles of RF, TF, and LF data collected under each working condition of the impact test are classified into different data sets. The data of each data set is taken as the ordinate, and the time is taken as the abscissa to plot a graph. Then 16 lines are fitted to obtain the average force values (RFavg, TFavg, and LFavg) in three directions vs. time. We select the RF and TF data for analysis, and process and analyze the RFavg vs. Time and TFavg vs. Time data to obtain RFpp (see Appendix Figure 2 ) and TFpp (Appendix Figure 3 ). For the impact resistance performance evaluation of tires of the same specification and different schemes, when the coefficient of variation C·V of RFpp or TFpp is ≥2.5%, it is determined that the radial or tangential impact resistance performance of the tire has obvious difference, otherwise when C·V <2.5%, the tire has no obvious difference in radial or tangential direction.

[0042] Peak to peak: The difference between the maximum and minimum values of the measured signal per revolution within a specified frequency bandwidth, i.e. the size of the tire over the protrusion. RFpp is the size of the radial force RF of the tire at the initial time of passing over the protrusion, and the smaller the RFpp, the smaller the initial radial impact force of the tire. TFpp is the size of the tangential force TF of the tire at the initial time of passing over the protrusion

[0043] Coefficient of variation: the ratio of standard deviation to mean is called coefficient of variation, denoted as C·V, the coefficient of variation is another statistical quantity for measuring the variation degree of each observation value in data. When comparing the variation degrees of two or more data, if the unit of measurement is the same as the mean, the standard deviation can be directly used for comparison. If the unit and (or) the mean are different, the standard deviation cannot be used to compare the variation degrees, and the ratio (relative value) of the standard deviation to the mean needs to be used for comparison.

[0044] The test tires for the specific test of the present application are two tires with a specification of 215 / 60R16, and the project numbers are A and B.

[0045] A rim meeting the standard requirements is installed on the tire A, and the tire is parked at the ambient temperature of the test room for at least 3 hours;

[0046] A 15mm (high) x 25mm (wide) right-angle impact bar and a matching weight are installed on the drum at the correct position; the impact bar is installed at an angle of 0 degrees horizontally;

[0047] The tire and rim combination is installed on the testing machine, and the test conditions are set according to Table 1;

[0048] The tire is warmed up at a speed of 30 km / h in the CW direction for 1 min, and then the tire is loaded and run at speeds of 30 / 40 / 50 / 60 km / h, respectively, to collect data, a total of 16 impact data are collected;

[0049] After the test is completed, the tire appearance is checked to confirm that the appearance is normal, and the test data are sorted and analyzed to obtain the RFpp values of the tire A at different speeds;

[0050] The tire B is tested according to the above steps, and the RFpp values of the tire B at different speeds are obtained.

[0051] The test results of the tires A and B are summarized together, and the average value and the standard deviation are calculated, and finally the coefficient of variation is obtained, and the results are shown in Table 2.

[0052] Table 2 Impact test data of 215 / 60R16 tire

[0053]

[0054] According to the test results, the radial impact performance of the A and B schemes has no obvious difference at the speeds of 30 km / h and 60 km / h, and has obvious difference at the speeds of 40 km / h and 50 km / h, and the radial impact force of the A tire is smaller, and the A tire is better than the B tire.

[0055] The foregoing description of the embodiments of the application has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the application be limited not with this detailed description, but rather by the claims appended hereto.

Claims

1. A method for indoor impact testing of automobile tires, characterized in that: The method uses a high-speed tire uniformity tester, and installs an impact bar on the drum of the high-speed tire uniformity tester at a horizontal position of 0 degrees. The method includes the following steps: 1) The tire is subjected to a loaded running impact test on a high-speed tire uniformity tester to obtain impact data, including radial force RF, tangential force TF, and lateral force LF; 2) The RF, TF, and LF data collected under each working condition of the impact test are grouped into different data sets. The data of each data set is plotted as the vertical axis and the time as the horizontal axis. Then, the fitting is performed to obtain the relationship between the average force values ​​RFavg, TFavg, and LFavg in the three directions and time. 3) Data from the RF and TF directions are selected for analysis. The RFavg vs. Time and TFavg vs. Time data are processed and analyzed to obtain the peak-to-peak values ​​RFpp and TFpp. The peak-to-peak value is the difference between the maximum and minimum values ​​of the measured signal per revolution within the specified bandwidth, representing the force exerted by the tire when it passes over the bump. RFpp is the radial force RF exerted by the tire at the initial moment of passing over the bump; the smaller the RFpp, the smaller the initial radial impact force. TFpp is the tangential force TF exerted by the tire at the initial moment of passing over the bump. 4) The ratio of the standard deviation to the mean is called the coefficient of variation, denoted as C·V. For the tire impact performance evaluation of tires of the same specifications but different designs, when the coefficient of variation C·V of the RFpp or TFpp value is ≥2.5%, it is determined that the tires have significant differences in radial or tangential impact performance. Conversely, when C·V is less than 2.5%, the tires have no significant differences in radial or tangential impact performance.

2. The method according to claim 1, characterized in that The impact bar has a square cross section.

3. The method according to claim 1, characterized in that The method also includes selecting a rim that meets the requirements of the standard and installing it on a vehicle tire, and placing the tire in a test room at an ambient temperature of 25±3°C for at least 3 hours.

4. The method according to claim 1, wherein The method also includes installing the tire and rim assembly on a testing machine, adjusting the air pressure to the test pressure, and setting the test speed and load.

5. The method according to claim 1 or 4, characterized in that The test conditions are as follows: Passenger car tires: test pressure 220 kPa; test load is maximum load capacity × 80%, test speed: 30-60 km / h; Light truck tires: test pressure 350 kPa; test load is 70% of the maximum load capacity of a single tire; test speed: 30-60 km / h.

6. The method according to claim 1, characterized in that The method also includes a visual inspection of the tire after the test. If any defects are found during the visual inspection, they must be noted in the report and new tires must be prepared for retesting.

7. An indoor impact test device for automobile tires, comprising a high-speed tire uniformity tester, a data acquisition module, and a calculation module, wherein an impact bar is installed horizontally at 0 degrees on the rotating drum of the high-speed tire uniformity tester; The data acquisition module is used to obtain the impact data of the tire during the loading and running test on the tire high-speed uniformity tester, including the radial force RF, the tangential force TF, and the lateral force LF; A computing module, configured to execute steps 2) to 4) of the method according to claim 1.

8. A computer device comprising a memory, a processor, and a computer program stored in the memory, wherein: The processor executes the computer program to implement steps 2) to 4) of the method according to claim 1.

9. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, steps 2) to 4) of the method according to claim 1 are implemented.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, steps 2) to 4) of the method according to claim 1 are implemented.

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