A method, use and computer program product for rapidly characterizing the dry grip capability of a tread

Abstract

The present application relates to the production technology field of tire, especially to a method for quickly characterizing the dry grip performance of the tread rubber, application and computer program product. The method innovatively divides the dry grip performance of the tread rubber into modulus part and friction keep through a large number of experiments. In the application, only a rubber dynamic mechanical analyzer (DMA) is used, and the dry performance of the tread rubber can be quickly obtained through simple data processing. The obtained result has good correlation with the actual tire dry braking distance.

Description

Technical Field

[0001] This invention relates to the field of tire manufacturing technology, and in particular to a method, application, and computer program product for rapidly characterizing the dry grip capability of tread rubber. Background Technology

[0002] The coefficient of friction of a tire on dry ground directly affects the braking distance of a car on dry ground. As the part in direct contact with the ground, the physical properties and viscoelastic characteristics of the tread compound are related to braking distance. European tire labeling regulations specify rolling resistance, noise, and wet grip performance, and there is considerable research on these three properties both domestically and internationally. For example, increasing the amount of silica and corresponding silane coupling agents in the tread can significantly reduce rolling resistance and improve wet grip. On the other hand, there is also considerable work characterizing the wet grip performance of tread compounds. For instance, in patent CN112967768A, the inventors described a method for calculating the wet adhesion friction coefficient using a vulcanized rubber composition and its application in tire design; and in CN112883320A, they described a method for calculating the wet hysteresis friction coefficient of a vulcanized rubber composition and its application in tire design. In the two patents above, the wet friction coefficient of the tire was divided into the adhesive friction coefficient and the hysteresis friction coefficient, and a good correlation was obtained with the actual vehicle tire results.

[0003] However, it is generally believed both domestically and internationally that, unlike wet grip performance which can be improved simply by increasing the amount of silica, the mechanism of dry grip appears to be much more complex. In China, OEMs generally place greater emphasis on dry grip performance than wet grip performance. However, the industry lacks a rapid method for characterizing dry grip resistance. Our patent CN111337274A used a portable oscillating friction coefficient tester (PSRT) to characterize wet grip, but PSRT proved ineffective on dry grip. Therefore, tire manufacturers and automakers often resort to making the tread compound into a tire and using actual vehicle braking distances to characterize dry grip, but this method is time-consuming and costly. Summary of the Invention

[0004] For the reasons stated above, the purpose of this invention is to provide a method for rapidly characterizing the dry grip capability of tire tread rubber. This method, through extensive experimentation, innovatively divides the grip contribution of the tread rubber into modulus contribution (MP) and friction keep (FK). In this invention, only a rubber dynamic mechanical analyzer (DMA) is used, and through simple data processing, the dry performance (DP) of the tread rubber can be quickly obtained. The obtained results show good correlation with actual tire dry braking distances.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for rapidly characterizing the dry grip ability of tire tread rubber, using a rubber dynamic mechanical analyzer, includes the following steps:

[0007] 1) Obtain E1', tanδ and E2' from the rubber dynamic mechanical analyzer, where E1' is the storage modulus at a certain point between 20 and 40℃, and tanδ is the hysteresis loss at a certain point between 20 and 40℃;

[0008] 2) Calculate the modulus contribution, MP = E1' / tanδ n The value of n is between -0.5 and 1.5;

[0009] 3) Calculate the friction retention coefficient, FK = E2' / E'1;

[0010] 4) Calculate the dry grip coefficient, DP=MP+FK.

[0011] As a preferred method, the temperature scanning test of the tread rubber using a rubber dynamic mechanical analyzer is as follows:

[0012] Temperature scanning range: -50~80℃; scanning frequency: 20Hz; static strain: 10%, dynamic strain: 1%.

[0013] Furthermore, the present invention also discloses the application of the method in screening tire tread compound formulations that resist dry rubbing.

[0014] Furthermore, the present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory, characterized in that the processor executes the computer program to implement the method.

[0015] Furthermore, the present invention also discloses a computer-readable storage medium having a computer program or instructions stored thereon, which, when executed by a processor, implement the method.

[0016] Furthermore, the present invention also discloses a computer program product, including a computer program or instructions that, when executed by a processor, implement the method.

[0017] Because of the above-mentioned technical solution, this invention uses only a rubber dynamic mechanical analyzer and simple data processing to quickly obtain the anti-dry grip coefficient of the tread rubber and obtain a good correlation with the actual dry braking distance of the tire. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the method of the present invention. Detailed Implementation

[0019] It is generally believed that the coefficient of friction of a tire on dry ground is related to the us curve (coefficient of friction and slip ratio), as shown in Figure 1. The coefficient of friction u mainly depends on two factors: first, the magnitude of umax, which is greatly affected by the modulus and is also related to the hysteresis factor of the rubber compound, which is defined as the modulus contribution MP in this invention; second, the degree to which the u value decreases with the increase of the slip ratio. The slower the decrease, the greater the friction force, which is related to the maintenance of the coefficient of friction, and is defined as FK in this invention.

[0020] This embodiment uses eight types of tread rubber, including high-performance treads and low rolling resistance treads, and implements the characterization method of the present invention.

[0021] (1) Temperature scanning test of DMA in tread rubber:

[0022] Temperature scanning range: -50~80℃; scanning frequency: 20Hz; static strain: 10%; dynamic strain: 1%;

[0023] (2) Data processing

[0024] ① Calculate the modulus contribution, MP = E1' / tanδ n ;

[0025] In the above formula, E1' is taken as the energy storage modulus at 20℃, tanδ is taken as the hysteresis loss at 20℃, and the value of n is taken as -0.3;

[0026] ② Calculate the friction retention coefficient, FK = E2' / E'1

[0027] In the above formula, E2' is the energy storage modulus at a certain point at 70℃;

[0028] ③ Calculate the dry grip coefficient, DP=MP+FK.

[0029] To verify the effectiveness of this invention, seven different tread compounds were used to make 205 / 55R16 tires, and real-vehicle tests were conducted to measure their dry braking distances. The braking speed was reduced from 80 km / h to 20 km / h, and the dry grip distance (DGD) was measured. The braking distance of tread compound A was set as 100, and the braking distances of the other compounds were compared to A. A higher DGD value indicates a shorter braking distance.

[0030]

[0031] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A method for rapidly characterizing the dry grip capability of a tire tread compound, characterized in that, The method uses a rubber dynamic mechanical analyzer for detection, including the following steps: 1) obtaining E1', tan delta and E2' of the rubber dynamic mechanical analyzer, wherein E1' is the storage modulus at a certain point at 20-40℃, tan delta is the hysteresis loss at a certain point at 20-40℃; 2) Calculate the modulus contribution, MP = E1' / tan delta n where n has a value between -0.5 and 1.

5. 3) calculating the friction retention coefficient, FK = E2' / E'1; 4) calculating the dry grip coefficient, DP = MP + FK.

2. A method of rapidly characterizing the dry grip capability of a tire tread rubber as defined in claim 1, wherein, The temperature scanning test of the rubber dynamic mechanical analyzer of the tread rubber is as follows: The temperature scanning range is: -50-80℃; the scanning frequency is: 20Hz; the static strain is 10%, and the dynamic strain is: 1%.

3. The application of the method according to claim 1 in screening the tire tread rubber formula with anti-dry friction.

4. A computer device comprising a memory, a processor, and a computer program stored on the memory, wherein the computer program comprises instructions that, when executed by the processor, cause the processor to perform the method of any one of claims 1-3. The processor executes the computer program to realize the method according to any one of claims 1-3.

5. A computer readable storage medium having stored thereon a computer program or instructions, characterized in that, The computer program or instructions are executed by the processor to realize the method according to any one of claims 1-3.

6. A computer program product comprising computer programs or instructions, characterized in that, The computer program or instructions are executed by the processor to realize the method according to any one of claims 1-3. The computer program or instructions are executed by the processor to realize the method according to any one of claims 1-3.

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