CN102359933A - System and method for testing all-weather tyre tread-road surface frictional characteristic - Google Patents

Abstract

The invention discloses an all-weather tire tread-road surface friction characteristic testing system and method. The testing system of the invention includes a console, a speed regulating motor, a rotary plate, a pressure plate, a hydraulic loading cylinder, a vertical pressure sensor, and a tire tread test block , environmental chamber, environmental control unit, horizontal tension and pressure sensor, friction road surface, etc., can realize the all-weather rubber covering the changing range of the working conditions of automobile tires (including various contact pressures, ambient temperature and humidity, slip speed, road conditions) The measurement of the friction coefficient between the tire tread and the road surface provides an effective technical means for obtaining the friction coefficient-slip speed curve of the rubber material. Combined with the proposed test system, the present invention uses the test method of short-time contact measurement to greatly reduce the influence of rubber wear and temperature rise on the experimental results in the rubber friction coefficient test, and significantly improve the repeatability and accuracy of the experimental results.

Description

All-weather tire tread-road surface friction characteristic testing system and method

technical field

The invention belongs to the field of tire tribology research, and specifically relates to an all-weather tire tread-road surface friction characteristic testing system and method, which can provide effective testing means and testing methods for the friction and wear properties of tire tread rubber materials. At the same time, it can provide a platform for measuring the friction characteristics of the tire-road surface at different speeds.

Background technique

As the main component of tires, rubber has special friction characteristics, which do not conform to Coulomb's law of friction. The mechanical properties of rubber tires largely depend on the friction properties of rubber (especially in some extreme conditions). At present, the theoretical research on rubber friction is still immature. Therefore, the test research of rubber friction is very important to the research of tire mechanical properties.

In order to study the friction characteristics of rubber, people have developed various testing equipment, which can be roughly divided into three categories: constant traction friction meter, constant speed friction meter and pendulum friction meter. The development of these devices has greatly advanced the theory of friction, but some features of these instruments make it difficult to study the friction characteristics of tires:

(1) Due to the limitation of the structure, the speed range is very narrow (mostly low speed, less than 1m/s);

(2) The friction medium is single and difficult to replace;

(3) The measurement time is long, resulting in severe wear and rapid heat generation of the test piece, which affects the accuracy of the measurement results;

(4) No ambient temperature control system;

(5) The application of the load is not automated, and the range of change is small.

Contents of the invention

In order to overcome the deficiencies of existing testing systems and methods, the present invention proposes an all-weather tire tread-road surface friction characteristic capable of obtaining the friction coefficient between the rubber tire tread and the road surface under specified pressure, temperature, humidity, and speed conditions Test system and method.

The present invention is realized through the following technical solutions:

An all-weather tire tread-road surface friction characteristic testing system, including: console 1, hydraulic source 2, speed regulating motor 3, rotating disc 4, pressure disc 5, hydraulic loading cylinder 6, vertical pressure sensor 7, tire tread test block 8. Environmental chamber 9, air duct 10, environmental control unit 11, speed sensor 12, main frame 13, horizontal tension and pressure sensor 14, friction road surface 15.

Wherein, the console 1 is respectively connected to the control speed regulating motor 3, the hydraulic loading cylinder 6, and the environment control unit 11 through data cables;

The hydraulic source 2 is connected to the hydraulic loading cylinder 6 through a hydraulic oil pipe to provide hydraulic power for it;

The speed regulating motor 3 realizes the transmission through the transmission mechanism inside the main frame 13 and the rotating disk 4, and provides a specified rotating speed for the rotating disk 4, so as to realize the adjustment of the slipping speed (0-30m/s) under the working speed of the automobile tire;

The pressure plate 5 is hinged on the lower part of the hydraulic loading cylinder 6, and the tire tread test block 8 is fixed on the lower end of the pressure plate 5. During the test, the pressure plate 5 is driven down by the hydraulic loading cylinder 6, so that the tire tread test block 8 and the rotating plate 4 Contact with the friction road surface 15 on the top, thereby forming the friction between the two;

The horizontal tension and pressure sensor 14 is installed between the pressure plate 5 and the main frame 13, and the horizontal force of the pressure plate 5 can be measured, and the frictional force received by the tire tread test block 8 can be calculated through moment balance; the vertical pressure sensor 7 is installed on the Between the pressure plate 5 and the hydraulic loading cylinder 6, the vertical force of the pressure plate 5 can be measured, and the value of the vertical load can be obtained by adding the self-weight of the loading mechanism, thereby obtaining the friction between the tire tread test block 8 and the friction road surface 15 coefficient;

The environmental control unit 11 is connected with the environmental cabin 9 through the air duct 10, and the environmental control unit 11 adjusts the temperature and humidity of the environmental cabin 9, and can realize the measurement of the coefficient of friction under different temperature and humidity conditions;

The speed sensor 12 is located below the rotating disk 4 and is fixed on the main frame 13 to measure the rotation speed of the rotating disk 4 .

It can be seen that the test system of the present invention can be used for testing the friction characteristics of the tire tread, and obtain test curves of the friction coefficient between the tire tread and different road surfaces as the sliding speed, vertical load, ambient temperature and humidity change.

Considering the problem of rapid temperature rise and wear during friction between the rubber tire tread-road surface, the present invention proposes a test method for the all-weather tire tread-road surface friction characteristics of automobile tires, the method adopts the above test system, through the control The contact time between the tire tread test block 8 and the friction road surface 15 can effectively obtain the friction coefficient test results under multiple working conditions. A kind of all-weather tire tread-road surface friction characteristic testing method of the present invention comprises the following steps:

(1) select the friction road surface 15, and realize the test of the friction coefficient between different road surfaces and the tire tread test block 8 by changing the friction road surface 15 of different surface materials, including ice surface, cement road surface, wet slippery road surface, etc.;

(2) Set the rotating speed of the speed regulating motor 3, the vertical loading force of the hydraulic loading cylinder 6, the temperature and the humidity of the environmental control unit 11 on the console 1;

(3) Control the speed regulating motor 3 to start by the console 1, and the rotating disk 4 starts to rotate; the hydraulic loading cylinder 6 is controlled by the console 1 to elongate, and the tire tread test block 8 is pressed down until the specified vertical loading force;

(4) measure the vertical load force in real time by the vertical pressure sensor 7, the frictional force between the tire tread test block 8 and the friction road surface 15 is measured in real time by the horizontal tension sensor 14, the speed sensor 12 measures the rotating speed of the rotating disk 4 in real time, and is controlled by the console 1 Simultaneously record the above-mentioned vertical loading force and friction force;

(5) The hydraulic loading cylinder 6 is controlled by the console 1 to lift up, and the speed regulating motor 3 stops;

(6) Display the measured friction coefficient result by console 1;

(7) The test is over.

According to the different working conditions of the slipping speed, the above steps can be fine-tuned. Here we mainly introduce two different working conditions of the high-speed section and the low-speed section:

A. When performing the tire tread friction test at high speed, that is, when the slipping speed is 1m/s~30m/s, first set the slipping speed and friction time, in order to avoid excessive friction between the tire tread test block 8 and the road surface 15 wear and tear, the contact time between the two should be shortened as much as possible; after loading, the tire tread test block 8 needs to have enough time to enter a stable state and to measure, so the whole test process is divided into four stages: no-load stage t ₀ , loaded Stage t ₁ , holding stage t ₂ , and unloading stage t ₃ , where: t ₀ - the waiting time after the motor starts and starts loading, t ₁ - the time from contact between tire tread block 8 and friction road surface 15 to load stabilization, t ₂ - time from load stabilization to tire tread block 8 starting to lift, t ₃ - time from motor stop, tire tread block 8 to lift. During the test, t ₁ ≤0.05s and t ₃ ≤0.05s can be controlled to ensure t ₂ ≥0.2s. The friction time t ₁ +t ₂ is controlled within 0.3s, so that the temperature of the friction surface is close to the temperature maintained in the environmental chamber during the no-load stage.

B. When performing the low-speed tire tread friction test, that is, when the slipping speed is 0-1m/s, the influence of heat generated by friction on the friction coefficient can basically be ignored. The contact time of tire tread test piece 8 and friction road surface 15 just can put longer like this. The specific steps are: 1. first make the speed-regulating motor 3 rotate at a low speed at a specified slip speed, the hydraulic loading cylinder 6 is extended, press down the tire tread block 8, and load the hydraulic loading cylinder 6 to the specified vertical loading force. ② Cut off the power supply of speed regulating motor 3 . At this time, the rotating disk 4 will continue to rotate due to inertia, but due to the effect of friction, its speed will gradually decrease to stop. While performing the previous two steps, continuously record the vertical loading force and friction force throughout the process. In this way, the friction coefficient of the low speed section can be obtained.

Beneficial effects of the present invention: the test system of the present invention can realize the relationship between the all-weather rubber tire tread and the road surface covering the variation range of the automobile tire working conditions (including various contact pressures, ambient temperature and humidity, slip speed, and road surface conditions). The measurement of the friction coefficient between them provides an effective technical means for obtaining the friction coefficient-slip speed curve of rubber materials. Combined with the proposed test system, the present invention uses the test method of short-time contact measurement to greatly reduce the influence of rubber wear and temperature rise on the test results in the rubber friction coefficient test, and significantly improve the repeatability and accuracy of the test results.

Description of drawings

Figure 1 All-weather tire tread-road surface friction characteristic test system;

The connection diagram of Fig. 2 horizontal tension and pressure sensor;

Fig. 3 flow chart of testing method for all-weather tire tread-road surface friction characteristics;

Figure 4 is a schematic diagram of the loading stage of the tire tread friction test in the high-speed section;

Fig. 5 flow chart of tire tread friction test in high-speed section;

Fig. 6 Flowchart of tire tread friction test in low-speed section.

In the figure: console 1, hydraulic source 2, speed regulating motor 3, rotary plate 4, pressure plate 5, hydraulic loading cylinder 6, vertical pressure sensor 7, tire tread test block 8, environmental chamber 9, air duct 10, environmental control Unit 11, speed sensor 12, main frame 13, horizontal tension and pressure sensor 14, friction road surface 15.

Detailed ways

Below in conjunction with accompanying drawing, technical scheme of the present invention is described further:

As shown in Figure 1, a kind of all-weather tire tread-road surface friction characteristic test system of the present invention comprises: console 1, hydraulic pressure source 2, speed regulating motor 3, rotating disc 4, pressure disc 5, hydraulic loading cylinder 6, Vertical pressure sensor 7, tire tread test block 8, environmental chamber 9, air duct 10, environmental control unit 11, speed sensor 12, main frame 13, horizontal tension and pressure sensor 14, friction road surface 15.

Wherein, the console 1 is respectively connected to the control speed regulating motor 3, the hydraulic loading cylinder 6, and the environment control unit 11 through data cables;

The hydraulic source 2 is connected to the hydraulic loading cylinder 6 through a hydraulic oil pipe to provide hydraulic power for it;

The speed regulating motor 3 realizes the transmission through the transmission mechanism inside the main frame 13 and the rotating disk 4, and provides a specified rotating speed for the rotating disk 4, so as to realize the adjustment of the slipping speed (0-30m/s) under the working speed of the automobile tire;

The pressure plate 5 is hinged on the lower part of the hydraulic loading cylinder 6, and the tire tread test block 8 is fixed on the lower end of the pressure plate 5. During the test, the pressure plate 5 is driven down by the hydraulic loading cylinder 6, so that the tire tread test block 8 and the rotating plate 4 Contact with the friction road surface 15 on the top, thereby forming the friction between the two;

As shown in Figure 2, the horizontal tension and pressure sensor 14 is installed between the pressure plate 5 and the main frame 13, and the force on the pressure plate 5 can be measured, and the frictional force received by the tire tread test block 8 can be calculated through moment balance; The pressure sensor 7 is installed between the pressure plate 5 and the hydraulic loading cylinder 6, which can measure the vertical force of the pressure plate 5, and the value of the vertical load can be obtained by adding the self-weight of the loading mechanism, so as to obtain the friction between the tire tread test block 8 and the friction road surface. The coefficient of friction between 15;

The environmental control unit 11 is connected with the environmental cabin 9 through the air duct 10, and the environmental control unit 11 adjusts the temperature and humidity of the environmental cabin 9, and can realize the measurement of the coefficient of friction under different temperature and humidity conditions;

The speed sensor 12 is located below the rotating disk 4 and is fixed on the main frame 13 to measure the rotation speed of the rotating disk 4 .

It can be seen that the test system of the present invention can be used for testing the friction characteristics of the tire tread, and obtain test curves of the friction coefficient between the tire tread and different road surfaces as the sliding speed, vertical load, ambient temperature and humidity change.

As shown in Figure 3, considering the problem of rapid temperature rise and wear during the friction between rubber tire tread-road surface, the present invention proposes a kind of all-weather tire tread-road surface friction characteristic test method for automobile tires, the method adopts The above testing system can effectively obtain the friction coefficient test results under multiple working conditions by controlling the contact time between the tire tread test block 8 and the friction road surface 15 . A kind of all-weather tire tread-road surface friction characteristic testing method of the present invention comprises the following steps:

(1) select the friction road surface 15, and realize the test of the friction coefficient between different road surfaces and the tire tread test block 8 by changing the friction road surface 15 of different surface materials, including ice surface, cement road surface, wet slippery road surface, etc.;

(2) Set the rotating speed of the speed regulating motor 3, the vertical loading force of the hydraulic loading cylinder 6, the temperature and the humidity of the environmental control unit 11 on the console 1;

(3) Control the speed regulating motor 3 to start by the console 1, and the rotating disk 4 starts to rotate; the hydraulic loading cylinder 6 is controlled by the console 1 to elongate, and the tire tread test block 8 is pressed down until the specified vertical loading force;

(4) measure the vertical load force in real time by the vertical pressure sensor 7, the frictional force between the tire tread test block 8 and the friction road surface 15 is measured in real time by the horizontal tension sensor 14, the speed sensor 12 measures the rotating speed of the rotating disk 4 in real time, and is controlled by the console 1 Simultaneously record the above-mentioned vertical loading force and friction force;

(5) The hydraulic loading cylinder 6 is controlled by the console 1 to lift up, and the speed regulating motor 3 stops;

(6) Display the measured friction coefficient result by console 1;

(7) The test is over.

According to the different working conditions of the slipping speed, the above steps can be fine-tuned. Here we mainly introduce two different working conditions of the high-speed section and the low-speed section:

A. As shown in Figure 4, when performing a high-speed tire tread friction test, that is, when the slipping speed is 1m/s to 30m/s, first set the slipping speed and friction time, in order to avoid tire tread test block 8 The contact time between the two should be shortened as far as possible due to the excessive wear of the friction road surface 15; after loading, the tire tread test block 8 needs to have enough time to enter a stable state and to measure, so the whole test process is divided into four stages: empty Loading stage t ₀ , loading stage t ₁ , maintaining stage t ₂ , and unloading stage t ₃ , where: t ₀ - the waiting time after the motor starts and starts loading, t ₁ - the contact between the tire tread block 8 and the frictional road surface 15 The time for the load to stabilize, t ₂ - the time from the load to the time when the tire tread block 8 starts to lift, t ₃ - the time when the motor stops and the tire tread block 8 is lifted. During the test, t ₁ ≤0.05s and t ₃ ≤0.05s can be controlled to ensure t ₂ ≥0.2s. The friction time t ₁ +t ₂ is controlled within 0.3s, so that the temperature of the friction surface is close to the temperature maintained in the environmental chamber during the no-load stage.

B. As shown in Figure 6, when the low-speed tire tread friction test is carried out, that is, when the slip speed is 0-1m/s, the influence of heat generated by friction on the friction coefficient can basically be ignored. The contact time of tire tread test piece 8 and friction road surface 15 just can put longer like this. The specific steps are: 1. first make the speed-regulating motor 3 rotate at a low speed at a specified slip speed, the hydraulic loading cylinder 6 is extended, press down the tire tread block 8, and load the hydraulic loading cylinder 6 to the specified vertical loading force. ② Cut off the power supply of speed regulating motor 3 . At this time, the rotating disk 4 will continue to rotate due to inertia, but due to the effect of friction, its speed will gradually decrease to stop. While performing the previous two steps, continuously record the vertical loading force and friction force throughout the process. In this way, the coefficient of friction in the low speed section can be obtained.

It should be noted that the above specific implementation is used as an example. Those of ordinary skill in the art will recognize many modifications, changes and modifications. These modifications, changes and modifications are all within the spirit and scope of the present application, and fall within the protection scope of the claims.

Claims (3)

1. An all-weather tire tread-road surface friction characteristic testing system, including: console (1), hydraulic pressure source (2), speed regulating motor (3), rotating disc (4), pressure disc (5), hydraulic loading Cylinder (6), vertical pressure sensor (7), tire tread test block (8), environmental chamber (9), air duct (10), environmental control unit (11), speed sensor (12), main frame (13) , horizontal tension and pressure sensor (14), friction road surface (15), it is characterized in that: The console (1) is respectively connected to the control speed regulating motor (3), the hydraulic loading cylinder (6) and the environment control unit (11) through data cables; The hydraulic source (2) is connected to the hydraulic loading cylinder (6) through a hydraulic oil pipe; The speed regulating motor (3) realizes the transmission through the transmission mechanism inside the main frame (13) and the rotating disc (4), and the sliding speed of the rotating disc (4) is adjusted between 0-30m/s; The pressure plate (5) is hinged at the lower end of the hydraulic loading cylinder (6), and the tire tread test block (8) is fixed at the lower end of the pressure plate (5); The horizontal tension and pressure sensor (14) is installed between the pressure plate (5) and the main frame (13), and can measure the horizontal force of the pressure plate (5); The vertical pressure sensor (7) is installed between the pressure plate (5) and the hydraulic loading cylinder (6), and can measure the vertical force of the pressure plate (5); The environmental control unit (11) is connected to the environmental cabin (9) through the air duct (10), and the environmental control unit (11) regulates the temperature and humidity of the environmental cabin (9); The speed sensor (12) is located under the rotating disk (4), is fixed on the main frame (13), and can measure the rotating speed of the rotating disk (4). 2. an all-weather tire tread-road surface friction characteristic testing method is characterized in that comprising the following steps: (1) Select the friction road surface (15): by changing the friction road surface (15) of different surface materials to realize the test of the friction coefficient between different road surfaces and the tire tread test block (8); (2) Set the rotating speed of the speed-regulating motor (3), the vertical loading force of the hydraulic loading cylinder (6), and the temperature and humidity of the environmental control unit (11) on the console (1); (3) Control the speed regulating motor (3) to start by the control console (1), and the rotating disk (4) starts to rotate; control the hydraulic loading cylinder (6) to extend by the control console (1), and press down the tire tread test block (8 ) until the specified vertical loading force; (4) Measure the vertical loading force in real time by the vertical pressure sensor (7), the horizontal tension sensor (14) measures the friction force between the tire tread test block (8) and the friction road surface (15) in real time, and the speed sensor (12) real-time Measure the rotational speed of the rotating disk (4), and record the above-mentioned vertical loading force and friction force synchronously by the console (1); (5) The hydraulic loading cylinder (6) is controlled by the console (1) to lift; the speed regulating motor (3) stops; (6) Display the measured friction coefficient result by console (1); (7) The test is over. 3. A kind of all-weather tire tread-road surface friction characteristic test method according to claim 2, is characterized in that according to the difference of slip speed working condition, above-mentioned steps can be fine-tuned: (1) When performing the tire tread friction test at high speed (slip speed 1m/s～30m/s), first set the slip speed and friction time, then the whole test process is divided into 4 stages: no-load stage t ₀ , loading stage t ₁ , holding stage t ₂ , unloading stage t ₃ ; in the test, control loading stage t ₁ ≤0.05s, holding stage t ₂ ≥0.2s, unloading stage t ₃ ≤0.05s, friction time t ₁ +t ₂ ≤0.3s; (2) When performing the tire tread friction test in the low-speed section (slip speed is 0-1m/s), the specific steps are: first, make the speed-regulating motor (3) drive the rotating disc (4) at a low speed at a specified slip speed Rotate, the hydraulic loading cylinder (6) is extended, press down the tire tread test block (8), and make the hydraulic loading cylinder (6) load to the specified vertical loading force; secondly, cut off the power supply of the speed regulating motor (3), and rotate at this time The speed of the disk (4) will gradually decrease until it stops; while the previous two steps are being carried out, the vertical loading force and friction force during the whole process are continuously recorded.

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