An evaluation method, device and computer program product for the indoor impact resistance performance of car tires

Abstract

The present invention belongs to the technical field of tire testing, and relates to a method for evaluating the indoor impact resistance performance of car tires. The present invention uses the dual-tire multi-air pressure method to quickly and effectively test the impact resistance performance of car tires while saving test costs, and performs fitting calculations on the test data to obtain the structural damage energy, elastic part, and stiffness coefficient of the hysteresis loss varying with air pressure under the theoretical zero-air pressure condition of car tires, so as to effectively determine the reasons for the differences in the impact resistance performance of car tires. The detection method of the present invention is reliable, the procedure is simple, and the number of test tires is reduced; the detection period is reduced while the detection accuracy is improved; the impact resistance performance of tires can be effectively identified and determined.

Description

Technical Field

[0001] The present invention belongs to the technical field of tire testing, and relates to a method for evaluating the indoor impact resistance performance of car tires. Background Art

[0002] When an automobile tire is subjected to an excessive external impact force, damage phenomena such as bulging, air leakage, and cracking will occur, which will cause relatively great harm to the safe driving of the automobile. The test methods for the impact resistance performance of tires mainly include the deep pit method and the curbstone method carried out on actual vehicles, as well as the pendulum method and the wedge method carried out in the laboratory. Among them, the pendulum method has received increasing attention in recent years. In 2020, the National Standardization Administration Committee issued GB / T 38528 "Evaluation of Impact Resistance Performance of Passenger Car Tires", which stipulates the evaluation requirements for the impact resistance performance of tires. The main technical index for evaluating the impact resistance performance of passenger car tires is the impact damage energy, which is calculated from the impact resistance factor corresponding to the aspect ratio of the tire and the corresponding tire specification information. The impact resistance factor has been proven to have a certain correlation with the impact test of the curbstone method on actual vehicles. In the pendulum method impact test, during the process of the tire being damaged by the pendulum impact, the pendulum impact energy is mainly converted into the tire elastic potential energy and hysteresis loss energy generated due to the deformation of the tire carcass, and the structural damage energy caused by the rim and the hammer head squeezing the tire sidewall resulting in the breakage of the cord. However, the concepts of impact damage energy and impact resistance factor do not directly indicate which part of the tire performance specifically affects the impact resistance performance.

[0003] When exploring the ultimate impact resistance ability of passenger car tires, a method is usually adopted in which the impact energy is increased in a large amplitude at the first impact point until the tire shows damage, and then the impact energy is increased in a small amplitude at different points in turn until the tire shows damage. For the impact resistance performance test under multi-pressure conditions, multiple tires are required to complete the test, the test cost is relatively high, and the differences between individual tires will have a greater impact on the test results.

[0004] Therefore, it is necessary to develop a multi-pressure impact resistance test method that avoids individual tire differences, and extract performance indicators that can be used to determine the causes of differences in the impact resistance performance of passenger car tires through data processing. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a method for testing the impact resistance performance of passenger car tires - the dual-tire multi-pressure method, which is fast, effective and saves test costs, and performs fitting calculations on the test data to obtain the structural damage energy, elastic part and stiffness coefficient of hysteresis loss varying with air pressure under the theoretical zero-air-pressure condition of the passenger car tire, so as to effectively determine the causes of differences in the impact resistance performance of passenger car tires.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for evaluating the indoor impact resistance of a car tire, the method comprising the following steps:

[0008] 1) The test is carried out on a crash resistance test equipment that complies with GB / T 30195; two identical passenger car tires are selected, divided equally according to the number of air pressure conditions, the air pressure is adjusted, the pendulum camber angle is set, and the multiple air pressure conditions are recorded as P1, P2, ..., Pn, and the air pressure interval should be no less than 20kPa;

[0009] 2) Each equally divided point on the tire corresponds to an air pressure condition. Each equally divided point on the first tire is impacted in a manner of increasing impact energy by a large amplitude △E. The interval between each impact is not less than 3 minutes. After a tire bulge occurs at an equally divided point, the air pressure is adjusted, the tire is rotated, and the next air pressure condition test is carried out. The impact energy E when the bulge occurs in each air pressure condition is recorded. 1―1 、E 1―2 ,......,E 1―n ;

[0010] 3) The impact energy of the first tire at each air pressure condition when the bulge occurs minus the incremental impact energy of the first tire is used as the initial impact energy of the corresponding air pressure condition of the second tire. If the tire does not bulge after the impact, the impact energy is first increased by △E / 3. If the tire still does not bulge after two incremental impacts, it is increased by △E / 6 until it bulges;

[0011] 4) The average of the impact energy before the bulge phenomenon occurred at each equally divided point and the impact energy when the bulge phenomenon occurred is taken as the impact damage energy of each air pressure condition, which is recorded as E 1 、E 2 ,......,E n ; The same processing method is used to treat the rebound energy as the elastic absorption energy of the tire, which is recorded as ∈ 1 ,∈ 2 ,......,∈ n ;

[0012] 5) Perform linear fitting on the impact damage energy and air pressure, and the intercept obtained is the maximum tolerable impact energy under zero air pressure conditions, which is used to characterize the structural damage energy of the tire and is recorded as E 0 , see formula (1);

[0013]

[0014] Combined with the deformation H when the tire bulges and the slope obtained by fitting, the stiffness coefficient k of the tire with the change of air pressure is calculated using formula (2): p, which is used to characterize the ratio of the increase in the overall rigidity of the tire with the increase in air pressure under the condition of unit deformation, dimensionless;

[0015]

[0016] 6) Perform a linear fit on the rebound energy and air pressure, and calculate the air pressure stiffness coefficient k of the elastic part of the tire according to formula (3) tp , which is used to characterize the coefficient of the increase in the stiffness of the elastic part of the tire with the increase in air pressure under the condition of unit deformation;

[0017]

[0018] And through formula (4), obtain the air pressure stiffness coefficient k of the hysteresis loss part of the tire zp , which is used to characterize the coefficient of the increase in the hysteresis loss part of the tire with the increase in air pressure under the condition of unit deformation;

[0019] k zp = k p ―k tp (4).

[0020] Preferably, if the phenomenon of the tire hitting and being damaged and cracked without air leakage occurs during step 2), it is regarded as a bulge. If there is air leakage, stop the test, replace the tire and reduce the increment for the test.

[0021] Furthermore, the present invention also discloses a computer device, including a memory, a processor, and a computer program stored on the memory, and the processor executes the computer program to implement steps 5)-6) in the method.

[0022] Furthermore, the present invention also discloses a computer-readable storage medium, on which a computer program or instruction is stored, and when the computer program or instruction is executed by a processor, steps 5)-6) in the method are implemented.

[0023] Furthermore, the present invention also discloses a computer program product, including a computer program or instruction, and when the computer program or instruction is executed by a processor, steps 5)-6) in the method are implemented.

[0024] Advantages of the present invention

[0025] (1) The detection method of the present invention is reliable, the procedure is simple, and the number of test tires is reduced;

[0026] (2) The present invention reduces the detection cycle and improves the detection accuracy at the same time;

[0027] (3) The present invention can effectively identify and determine the impact resistance performance of the tire. Description of the drawings

[0028] Figure 1 It is the impact process diagram of Tire No. 1, taking five points as an example.

[0029] Figure 2 It is the impact process diagram of Tire No. 2, taking five points as an example.

[0030] Figure 3 It is the test and data processing flow chart for the impact resistance performance of car tires. Specific implementation manners

[0031] The technical solution of the present invention will be further described below through specific implementation cases.

[0032] In order to distinguish the differences in the impact resistance performance between different car tires, two 195 / 55R16 tires of the same specification but different brands, two for each, are selected, installed on the test rims that meet the standard requirements, and parked in the laboratory environment for at least 3 hours, numbered as A-1#, A-2#, B-1#, and B-2# respectively. The multi-air pressure conditions are determined as 300 kPa, 250 kPa, 220 kPa, 200 kPa, and 180 kPa, and each tire is marked in five equal parts. The test and data processing processes are as follows:

[0033] 1. Install Tire No. 1 on the impact resistance test machine that meets GB / T 30195, set the impact camber angle to 6°, adjust the air pressure to 300 kPa ± 2 kPa, and rotate the tire to one of the equal part marking points as the initial impact point position.

[0034] 2. Impact this point in the way of increasing the impact energy by 120 J each time, with an interval of not less than 3 minutes between each impact, until a bulge appears at this point and record the impact energy when the bulge appears.

[0035] 3. Adjust the tire air pressure to 250 kPa ± 2 kPa, rotate the tire to the next equal part marking point, let it stand for 10 minutes, then impact this point in the way of increasing the impact energy by 120 J each time until a bulge appears at this point and record the impact energy when the bulge appears. The test and recording are also carried out in the same way under other air pressures. The impact energies when bulges appear at each point of Tire No. 1 are shown in Table 1.

[0036] Table 1 Impact energy when Tire No. 1 bulges

[0037]

[0038]

[0039] 4. Install Tire No. 2 on the impact resistance test machine, adjust the air pressure to 300 kPa ± 2 kPa, and rotate the tire to one of the equal part marking points as the initial impact point position.

[0040] 5. Impact the point with the impact energy when a bulge appears under the same air pressure condition as that of Tire No. 1 minus 120 J as the starting impact energy. If the tire does not bulge, increase it by 40 J or 20 J (increase by 40 J for the first two times and then increase by 20 J) until the tire bulges and record the impact energy and rebound energy when the bulge appears. Conduct the test and record in the same way under other air pressures. The impact energies when the bulges appear at each point of Tire No. 2 are shown in Table 2 and Table 3.

[0041] Table 2 Impact Record Table of A - Tire No. 2

[0042] Point position Air pressure Impact energy (J) Rebound energy (J) Tire bulging condition 1 300 840 562.0 1 300 880 578.8 Bulge 2 250 720 478.5 2 250 760 494.5 2 250 800 509.8 Bulge 3 220 600 438.1 3 220 640 454.2 3 220 680 467.4 3 220 700 485.2 Bulge 4 200 600 403.6 4 200 640 409.2 4 200 680 425.2 Bulge 5 180 480 334.2 5 180 520 352.5 5 180 560 368.1 5 180 580 375.6 5 180 600 381.5 Bulge

[0043] Table 3 Impact Record Table of B - Tire No. 2

[0044]

[0045]

[0046] 6. Take the average value of the impact energy when the tire bulges and the previous impact energy as the impact failure energy of the tire, and take the average value of the rebound energy when the tire bulges and the previous rebound energy as the maximum recoverable energy of the tire. The calculation results are shown in Table 4.

[0047] Table 4 Impact Failure Energy and Maximum Recoverable Energy of Tire No. 2

[0048]

[0049] 7. Use Formulas (1) - (4) to calculate the structural failure energy, elastic air pressure stiffness coefficient, and hysteresis loss air pressure stiffness coefficient of the tire respectively, as shown in Table 5. It can be seen from the table that the impact resistance performance of the tires of Brand B is better than that of Brand A. The reason is that the tires of Brand B have higher structural failure energy of the tire, as well as similar elastic part air pressure stiffness coefficients and hysteresis loss part air pressure stiffness coefficients.

[0050] Table 5 Structural Failure Energy of the Tire and Air Pressure Stiffness Coefficient

[0051]

[0052] The above is the description of the embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. 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 herein, but will be accorded the widest scope consistent with the principles and novel points disclosed herein.

Claims

1. An evaluation method for the indoor impact resistance performance of car tires, characterized in that, the method comprises the following steps: 1) The test is carried out on an impact resistance test device that complies with GB / T 30195; select two identical car tires, divide them equally according to the number of air pressure working conditions, adjust the air pressure, set the pendulum camber angle, and record the multi-air pressure working conditions as P 1 , P 2 ,......, P n , and the air pressure interval should be no less than 20 kPa; 2) Each equally divided point on the tire corresponds to a pneumatic pressure condition. Each equally divided point on the first tire is impacted in a manner of increasing the impact energy by a large margin of △E, and the interval between each impact is not less than 3 minutes. After a tire bulge phenomenon appears at an equally divided point, adjust the pneumatic pressure, rotate the tire, and conduct the test for the next pneumatic pressure condition, and record the impact energy when the tire bulge phenomenon appears under each pneumatic pressure condition. 、 、......、 ; 3) Subtract the incremental amount of the impact energy of the first tire from the impact energy when the first tire bulges under each air pressure condition as the initial impact energy of the corresponding air pressure condition of the second tire. If the tire does not bulge after the impact, the impact energy increases by △E / 3 first. If the tire still does not bulge after two incremental impacts, it increases by △E / 6 until it bulges. 4) The average of the impact energy before the bulging phenomenon occurs at each equal division point and the impact energy when the bulging phenomenon occurs is used as the impact failure energy for each air pressure condition, denoted as 、 、......、 ; Using the same processing method, the rebound energy is used as the elastic absorption energy of the tire, denoted as 、 、......、 ; 5) Perform a linear fit on the impact damage energy and air pressure. The intercept obtained represents the maximum impact energy that can be tolerated under zero air pressure conditions, which is used to characterize the structural damage energy of the tire and is denoted as , as shown in Equation (1); Combined with the deformation amount H when the tire bulges and the fitted slope, the stiffness coefficient of the tire varying with air pressure is calculated by formula (2) , which is used to characterize the proportion of the increase in the overall rigidity of the tire with the increase in air pressure under the condition of unit deformation amount, dimensionless 6) Perform a linear fit on the rebound energy and air pressure, and calculate the air pressure stiffness coefficient of the elastic part of the tire using formula (3) , which is used to characterize the coefficient of the increase in the stiffness of the elastic part of the tire with the increase in air pressure under the condition of unit deformation And through formula (4), the air pressure stiffness coefficient of the tire hysteresis loss part is obtained , which is used to characterize the coefficient of the increase in the tire hysteresis loss part with the increase in air pressure under the condition of unit deformation; 。 2. The evaluation method for the indoor impact resistance performance of car tires according to claim 1, characterized in that, During the process of step 2), if the tire is damaged and cracked but not leaking air after the impact, it is regarded as bulging. If there is air leakage, the test is stopped, the tire is replaced, and the incremental amount is reduced for the test.

3. 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 implement steps 5)-6) in the method according to claim 1.

4. A computer-readable storage medium, on which a computer program or instruction is stored, characterized in that, when the computer program or instruction is executed by the processor, it implements steps 5)-6) in the method according to claim 1.

5. A computer program product, comprising a computer program or instruction, characterized in that, when the computer program or instruction is executed by the processor, it implements steps 5)-6) in the method according to claim 1.

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