CN118776925A - A method, device and computer program product for indoor impact testing of automobile tires - Google Patents

Abstract

The present invention relates to the technical field of tire performance testing, and in particular to an indoor impact test method, equipment and computer program product for automobile tires. The method installs an impact bar on the drum of a high-speed tire uniformity tester, uses the impact bar to test the impact force and attenuation performance, and uses the coefficient of variation C·V of the peak-to-peak value RFpp or TFpp value to evaluate the impact resistance of a tire, which is convenient for selecting tire solutions and for conducting correlation research with the results of real vehicle comfort tests.

Description

A method, device and computer program product for indoor impact testing of automobile tires

Technical Field

The present invention relates to the technical field of tire performance testing, and in particular to an indoor impact test method, equipment and computer program product for automobile tires.

Background Art

When a tire passes through an irregular road, a rough road, or a road with obstacles, the moment the tire contacts the obstacle, the tire is impacted and deformed, and the tire generates a force on the rim through the contact part between the tire mouth and the rim. The tire has a certain containment characteristic, and some obstacles 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 characteristics is crucial to the comfort of the entire vehicle.

The evaluation of tire impact performance generally relies on the subjective evaluation results of the vehicle's ride comfort. The vehicle wheel impact test is conducted at high speed, which can easily cause damage to test personnel and test equipment. At the same time, the subjective evaluation process includes the influence of the evaluation engineer's subjective personal preferences, and the cost of vehicle testing is expensive. In order to evaluate tire impact performance before the subjective evaluation process, so as to facilitate the development of tires, shorten the development cycle, and save development costs, it is necessary to accurately and objectively evaluate tire impact performance without subjective evaluation.

A Chinese invention patent application (publication number: CN115452300A, publication date: 2022-12-09) discloses a test method for a dynamic impact test of a tire, comprising the following steps: test preparation: installing a tire rim assembly on a test device, the test device comprising a load wheel, an excitation object is arranged on the surface of the load wheel, a load is applied to the tire and the load wheel surface is contacted; t impact tests: taking t test points 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 the test speed, and records the fluctuation of the force in each direction of the tire during the process of each test point passing through the excitation object; wherein t is a common divisor of 2 and 3 or a common divisor of 2, 3 and 4; taking the average value of the results of the t impact tests for subsequent analysis. This method requires the design of the test equipment, and only gives the test method, but does not give how to perform data analysis and how to evaluate.

The tire high-speed uniformity tester used in the present invention is a physical performance testing instrument used in the field of chemical engineering, and is used for radial force, lateral force, tangential force fluctuation, runout, flat spot test, obstacle test and balance test of tires at high speed.

Summary of the invention

In order to solve the above technical problems, the purpose of this application is to provide an indoor impact test method for automobile tires. This method installs an impact bar on the drum of a high-speed tire uniformity tester, uses the impact bar to test the impact force and attenuation performance, and uses the coefficient of variation C·V of the peak-to-peak RFpp or TFpp value to evaluate the impact resistance of a tire, which is convenient for the selection of tire solutions and the correlation study with the actual vehicle comfort test results.

In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

An indoor impact test method for automobile tires, the method adopts a high-speed tire uniformity tester, and an impact bar is installed and arranged horizontally at 0 degrees on the drum of the high-speed tire uniformity tester; the method comprises the following steps:

1) The tire is subjected to a loading and 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 classified into different data sets, and the data of each data set is used as the vertical axis and the time is used as the horizontal axis for plotting. 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) Select the data in RF and TF directions for analysis, and process and analyze the RFavg vs. Time and TFavg vs. Time data 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 in each revolution within the specified bandwidth, that is, the force of the tire when it passes over the protrusion; RFpp is the radial force RF of the tire at the beginning of passing over the protrusion, the smaller the RFpp, the smaller the initial radial impact force of the tire; TFpp is the tangential force TF of the tire at the beginning of passing over the protrusion;

4) The ratio of the standard deviation to the mean is called the coefficient of variation, denoted as C·V. For the evaluation of tire impact resistance of tires of the same specifications but different schemes, when the coefficient of variation C·V of the RFpp or TFpp value is ≥2.5%, it is judged that the tire has obvious differences in radial or tangential impact resistance. Conversely, when C·V＜2.5%, there is no obvious difference in the radial or tangential impact resistance of the tire.

Preferably, the impact strip has a square cross-section.

Preferably, the method further comprises selecting a rim that complies with the standard to install 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.

Preferably, the method further comprises 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.

Preferably, 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 single tire maximum load capacity × 70%, test speed: 30-60 km/h.

Preferably, the method also includes performing a visual inspection of the tire after the test. The visual inspection should not show any defects in the tread, sidewall, cord layer, belt layer or buffer layer and bead delamination, cord layer cracks, cord peeling, cord breakage, flower chipping, joint cracking, cracking and abnormal tire deformation. If the above defects are found, they must be noted in the report and a new tire must be prepared for retesting.

Furthermore, the present invention also discloses an indoor impact test device for automobile tires, which includes 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 a rotating drum of the high-speed tire uniformity tester;

A 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 radial force RF, tangential force TF, and lateral force LF;

A computing module is used to execute steps 2) to 4) in the method.

Furthermore, the present invention also discloses a computer device, including 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) in the method.

Furthermore, the present invention also discloses a computer-readable storage medium on which a computer program or instruction is stored. When the computer program or instruction is executed by a processor, step 2) to step 4) of the method are implemented.

Furthermore, the present invention also discloses a computer program product, including a computer program or an instruction, which implements step 2) to step 4) in the method when the computer program or the instruction is executed by a processor.

The present invention adopts the above technical solution. The method installs an impact bar on the drum of a high-speed tire uniformity tester, uses the impact bar to test the impact force and attenuation performance, and uses the coefficient of variation C·V of the peak-to-peak RFpp or TFpp value to evaluate the impact resistance of a tire, which is convenient for selecting tire solutions and convenient for correlation research with actual vehicle comfort test results.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the device of the present invention, wherein 1: rotating drum, 2: impact bar, 3: tire, 4: rim.

Figure 2 is a schematic diagram of an impact bar.

FIG3 is a schematic diagram of the tire impact test RF vs. Time test.

FIG4 is a schematic diagram of a tire impact test TF vs. Time test.

DETAILED DESCRIPTION

The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

An indoor impact test method for automobile tires, the method comprising the following steps:

1) Tire installation and parking: Select rims that meet the standards and install them on the car tires, and park the tires at the test room ambient temperature (25±3℃) for at least 3 hours;

2) Impact bar installation: Install the 15mm (height) x 25mm (width) right-angle impact bar (see Figure 1) and the matching counterweight block on the drum in the correct position; Impact bar installation angle: horizontal 0 degrees;

3) Installation of tire-rim assembly: Install the tire-rim assembly on the testing machine and adjust the air pressure to the test pressure. Set the test speed and load;

4) Impact test: The tire is warmed up for 1 minute in the CW (clockwise) direction at a certain speed, and the tire is loaded and operated according to Table 1 to collect data. A total of 16 impact data are collected, including radial force RF (Radial Force), tangential force TF (Tangential Force), lateral force LF (Lateral Force), etc.

Table 1 Impact test conditions

Tire type Test air pressure (holding air, kPa) Test load (kg) Test speed (km/h) Passenger car tires 220 Maximum load capacity × 80% 30-60 Light truck tires 350 Maximum load capacity of a single tire × 70% 30-60

5) Tire appearance inspection: After the test, the tire appearance inspection should be carried out. The appearance inspection should not have defects such as (tread, sidewall, cord layer, belt layer or buffer layer, bead) delamination, cord layer cracks, cord peeling, cord breakage, flower chipping, joint cracking, cracking, and abnormal tire deformation. If the above defects are found, they must be noted in the report and new tires must be prepared for retesting.

6) Data classification, processing and evaluation

The 16 circles of RF, TF, and LF data collected under each working condition of the impact test were classified into different data sets, and the data of each data set was used as the vertical axis and the time was used as the horizontal axis for plotting. Then, 16 lines were fitted to obtain the relationship between the average force values (RFavg, TFavg, and LFavg) in the three directions and time. We selected the data in the RF and TF directions for analysis, and processed and analyzed the RFavg vs. Time and TFavg vs. Time data to obtain RFpp (see Figure 2) and TFpp (Figure 3). For the evaluation of tire impact resistance of tires with the same specifications but different schemes, when the coefficient of variation C·V of the RFpp or TFpp value is ≥2.5%, it is determined that the tire has significant differences in radial or tangential impact resistance. Conversely, when C·V is <2.5%, there is no significant difference in the radial or tangential impact resistance of the tire.

Peak to peak: The difference between the maximum and minimum values of the measured signal in each revolution within the specified bandwidth, that is, the force of the tire when it passes over the protrusion. RFpp is the radial force RF of the tire when it initially passes over the protrusion. The smaller the RFpp, the smaller the initial radial impact force of the tire. TFpp is the tangential force TF of the tire when it initially passes over the protrusion.

Coefficient of variation: The ratio of the standard deviation to the mean is called the coefficient of variation, denoted as C·V. The coefficient of variation is another statistic that measures the degree of variation of each observation in the data. When comparing the degree of variation of two or more data, if the measurement unit is the same as the mean, the standard deviation can be used directly for comparison. If the unit and (or) the mean are different, the standard deviation cannot be used to compare the degree of variation, but the ratio of the standard deviation to the mean (relative value) must be used for comparison.

The test tires for the specific test of the present invention are two tires with a specification of 215/60R16, and the solution numbers are A and B.

Install the rim that meets the requirements of the standard onto tire A and place the tire at the ambient temperature of the test room for at least 3 hours;

Install the 15mm (height) x 25mm (width) right-angle impact bar and the matching counterweight block on the drum in the correct position; the impact bar installation angle: horizontal 0 degrees;

Install the tire and rim assembly on the testing machine and set the test conditions according to Table 1;

The tire was warmed up for 1 minute at a speed of 30 km/h in the CW direction, and then loaded and operated at 30/40/50/60 km/h to collect data. A total of 16 impact data were collected.

After the test, the tire appearance is inspected to confirm that the appearance is normal, and the test data is sorted and analyzed to obtain the RFpp value of tire A at different speeds;

Repeat the above steps to test tire B and obtain the RFpp values of tire B at different speeds.

The test results of tires A and B were summarized together, and the mean and standard deviation were calculated to finally obtain the coefficient of variation. The results are shown in Table 2.

Table 2 215/60R16 tire impact test data

According to the above test results, for Schemes A and B at speeds of 30km/h and 60km/h, C•V(RFpp)≤2.5%, and at speeds of 40km/h and 50km/h, C•V(RFpp)＞2.5%. Therefore, it is believed that there is no significant difference in radial impact performance between Schemes A and B at speeds of 30km/h and 60km/h, but there is a significant difference in radial impact performance at speeds of 40km/h and 50km/h. The radial impact force of Tire A is smaller, which is better than that of Tire B.

The above is a description of the embodiments of the present invention. Through the above description of the disclosed embodiments, professionals and technicians in the field can implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will conform to the widest range consistent with the principles and novelties disclosed herein.

Claims (10)

1. The method is characterized in that a tire high-speed uniformity testing machine is adopted, and impact strips are arranged on a rotary drum of the tire high-speed uniformity testing machine according to a transverse angle of 0 degrees; the method comprises the following steps:

1) The tire performs loading operation impact test on a tire high-speed uniformity testing machine to obtain impact data, wherein the impact data comprises radial force RF, tangential force TF and transverse force LF;

2) Respectively classifying the RF, TF and LF data collected under each working condition of the impact test into different data sets, plotting the data of each data set as an ordinate and the time as an abscissa, and then fitting to obtain the relationship diagram of average force values RFavg, TFavg and LFavg in three directions and time respectively;

3) Data in the directions of RF and TF are selected for analysis, and RFavg vs. time and TFavg vs. time data are processed and analyzed to obtain peak values RFpp and TFpp; the peak-to-peak value is the difference between the maximum value and the minimum value of the measurement signal in each revolution within the specified frequency bandwidth, namely the size of the tire passing over the protruding material resources; RFpp is the magnitude of the radial force RF of the tire when the tire passes over the protrusion, and the smaller RFpp is, the smaller the initial radial impact force of the tire is; TFpp is the tangential force TF of the tire at the beginning of passing over the protrusions;

4) The ratio of standard deviation to average number is called coefficient of variation, and is marked as C.V, when the coefficient of variation C.V of RFpp or TFpp value is more than or equal to 2.5%, it is judged that the tire has obvious difference in radial or tangential impact resistance, otherwise when C.V is less than 2.5%, the tire has no obvious difference in radial or tangential impact resistance.

2. The method of claim 1, wherein the impingement strip is square in cross-section.

3. The method of claim 1 further comprising selecting a rim that meets the standard specification for mounting to an automobile tire and parking the tire at a test room ambient temperature of 25±3 ℃ for at least 3 hours.

4. The method of claim 1, further comprising mounting the tire and rim combination to a testing machine and adjusting the air pressure to a test air pressure, setting a test speed, and loading.

5. The method according to claim 1 or 4, characterized in that the test conditions are as follows:

Car tyre: test air pressure 220 kPa; test load is maximum load capacity x 80%, test speed: 30-60 km/h;

Light truck tire: test air pressure 350 kPa; test load is single tire maximum load capacity x 70%, test speed: 30-60 km/h.

6. The method of claim 1, further comprising performing a tire appearance inspection after the test is completed, the appearance inspection being free of tread, sidewall, ply, belt or breaker and bead delamination, ply cracking, cord peeling, cord breakage, chipping, joint cracking, crazing, and abnormal deformation defects of the carcass, if any, as noted in the report and preparing additional new tire retests.

7. The equipment comprises a tire high-speed uniformity testing machine, a data acquisition module and a calculation module, wherein an impact strip is arranged on a rotary drum of the tire high-speed uniformity testing machine according to a transverse 0-degree installation;

the data acquisition module is used for acquiring impact data of the tire when the tire is subjected to a loading operation test on the tire high-speed uniformity testing machine and comprises radial force RF, tangential force TF and transverse force LF;

A calculation module for performing steps 2) -4 of the method of claim 1.

8. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out steps 2) -4 of the method of claim 1.

9. A computer readable storage medium having stored thereon a computer program or instructions which, when executed by a processor, performs steps 2) -4 of the method of claim 1.

10. A computer program product comprising a computer program or instructions which, when executed by a processor, performs steps 2) -4 of the method of claim 1.