Truck tire reliability evaluation method under high-temperature and heavy-load severe use working conditions

Abstract

The invention relates to the technical field of tire performance detection, in particular to a lorry tire reliability evaluation method under high-temperature and heavy-load severe use working conditions, which comprises the following steps: performing high-temperature resistance test and heavy-load resistance test on a tire, and when the high-temperature resistance and the heavy-load resistance are judged to be excellent at the same time, evaluating the reliability of the tire as meeting the requirements. High-temperature and heavy-load conditions in the using process of the truck tire are simulated through tests, strict performance testing is conducted on the tire, the performance of the tire under the severe working condition is evaluated, a whole vehicle enterprise can be guided to select the tire under the high-temperature and heavy-load using working condition, the tire with the high-temperature-resistant and heavy-load-resistant performance meeting the requirement is screened out, and the service life of the tire is prolonged. Therefore, the driving stability and safety of the whole truck are improved, a certain basis is provided for research and development of truck tires, and important practical value and popularization prospects are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of tire performance detection, and in particular to a reliability evaluation method for a heavy-duty automobile tire under high-temperature, heavy-load and harsh operating conditions. Background Art

[0002] Truck tires are specially designed for tractors, dump trucks, trucks, various special vehicles and trailers, with high load-bearing capacity and good wear resistance. These tires are usually used on complex driving roads, including good asphalt roads and poor gravel roads, dirt roads, muddy roads, ice and snow roads, etc. Truck tires are an important part of the vehicle, and the performance of the tires is related to the driving stability and safety performance of the entire vehicle.

[0003] With the rapid development of the transportation industry, the demand for trucks to operate under harsh conditions such as high temperature and heavy load is increasing, such as continuous operation without stopping, high-speed operation under heavy load, continuous downhill braking and high temperature, etc., which puts higher requirements on the performance of truck tires. Traditional testing methods mainly focus on testing the outer edge, strength, durability, high speed and other performance of tires under normal temperature conditions, which cannot fully reflect the true performance of tires under extreme conditions.

[0004] Currently, although high-performance truck tires on the market claim to be able to cope with harsh working conditions, there is a lack of scientific and systematic testing and analysis methods to verify their performance. Under high temperature conditions, tire materials may age and harden, resulting in reduced performance; under heavy load conditions, tires may be subjected to pressures exceeding the designed load, resulting in bulges or even blowouts. Therefore, a new testing and analysis method is needed to comprehensively evaluate the performance and reliability of tires under extreme working conditions such as high temperature and heavy load. Summary of the invention

[0005] In view of the technical problem that it is difficult to comprehensively evaluate the high temperature and heavy load resistance performance of heavy-duty truck tires in the prior art, the present invention provides a reliability evaluation method for heavy-duty truck tires under high temperature and heavy load harsh operating conditions. By simulating high temperature and heavy load extreme conditions during use, the reliability of the tires under high temperature and heavy load conditions is comprehensively evaluated, and the aging, bulging, and blowout phenomena that occur during the use of the tires are minimized. Tires that meet the requirements for high temperature and heavy load resistance are screened for use, thereby improving the driving stability and safety of the entire vehicle.

[0006] The present invention provides a reliability evaluation method for a heavy-duty automobile tire under high-temperature and heavy-load harsh use conditions, comprising: simulating high-temperature and heavy-load conditions during tire use through high-temperature resistance tests and heavy-load resistance tests, evaluating the reliability of the tire under high-temperature and heavy-load conditions, and analyzing and selecting tires with excellent high-temperature resistance and heavy-load resistance performance for installation and use; The present invention investigates the vehicle usage conditions before the high temperature resistance test and the heavy load resistance test, including the vehicle model, vehicle usage environment temperature, vehicle load condition, road condition, vehicle speed, transportation distance, operation cycle, cargo type, etc.

[0007] The methods for high temperature resistance testing include: (a1) drilling holes at the tire tread to obtain temperature measuring holes, and mounting the tire on a standard rim to obtain a tire-rim assembly; (a2) The tire-rim assembly is mounted on a drum test shaft, and at least four speeds within the highest rated speed of the tire are selected as test speeds. The drum test is carried out at each test speed in sequence starting from the lowest test speed until all selected test speeds are tested or the tire begins to be damaged; the method for carrying out the test at each test speed is to test the temperature in the temperature measuring hole every 1 hour of operation until the temperature of the temperature measuring hole remains stable, record the temperature value at the test speed as the equilibrium temperature value, and stop the test; (a3) Calculate the TKPH value at each test speed, and use the TKPH value at each test speed as y and the equilibrium temperature value as x to fit a linear regression fitting equation y=f(x). Calculate the TKPH rated value of the tire at the critical temperature based on y=f(x). If the TKPH rated value of the tire is ≥ the TKPH on-site value, the high temperature resistance performance of the tire is judged to be excellent. The methods for heavy load resistance testing include: (b1) Mounting the tire on a standard rim to obtain a tire-rim assembly, and inflating the tire to an air pressure corresponding to the maximum single tire load; (b2) The tire-rim assembly is mounted on the test drum shaft, ensuring that the tire is vertical and in close contact with the outer surface of the drum. Pressure is applied and the drum is started. If there is no abnormality in the tire when the test time reaches 60 hours, the tire's heavy load resistance performance is judged to be qualified. If there is no abnormality in the tire when the test time is ≥ 90 hours, the tire's heavy load resistance performance is judged to be excellent.

[0008] Furthermore, in step (a1), the number of the temperature measuring holes is at least four, the drilling position of each temperature measuring hole is located at the center of the pattern, the diameter of the temperature measuring hole is 5±0.5 mm, and the distance between the bottom end of the temperature measuring hole and the uppermost cord layer is ≤5 mm.

[0009] Furthermore, in step (a1), the tire-rim assembly is placed in an environment with a temperature of 38±3° C. for 24 hours.

[0010] Furthermore, in step (a2), when four test speeds are selected, the test speeds are 0.5V, 0.67V, 0.83V, and V, respectively, where V is the maximum rated speed of the tire.

[0011] Furthermore, in step (a2), the condition for the temperature of the temperature measuring hole to remain stable is that the temperature of the same temperature measuring hole stops rising after three consecutive measurements, or the difference between the maximum and minimum values ​​of the three temperature measurements is less than 3°C.

[0012] Furthermore, in step (a1), the tire is inflated to an air pressure corresponding to the maximum single tire load; in step (a2), pressure is applied to the tire, and the tire load is set to 80% to 90% of the maximum rated load of the tire.

[0013] Furthermore, the calculation method of TKPH value = tire load × test speed.

[0014] Furthermore, TKPH field value = average load under working conditions × average speed under working conditions × temperature correction coefficient; the calculation method of temperature correction coefficient is: when the ambient temperature is greater than 38°C, ; When the ambient temperature = 38℃, the temperature correction coefficient = 1; When the ambient temperature < 38℃, .

[0015] Furthermore, a pressure of 180% to 200% of the maximum rated load of the tire is applied to the tire; after the drum is started, the tire is uniformly accelerated to 10 to 30 km / h within 5 minutes.

[0016] Furthermore, in step (b2), the abnormal condition includes tire bulging and / or tire blowout.

[0017] The beneficial effects of the present invention are as follows: the reliability evaluation method of heavy-duty vehicle tires under high-temperature, heavy-load and harsh operating conditions provided by the present invention simulates the high-temperature and heavy-load conditions during the use of heavy-duty vehicle tires through experiments, performs strict performance tests on the tires, and evaluates their performance under harsh conditions. This method can not only guide vehicle manufacturers in the selection of tires under high-temperature and heavy-load operating conditions, and screen tires that meet the requirements for high-temperature resistance and heavy-load resistance for installation and use, thereby improving the driving stability and safety of the entire vehicle, but also provides a certain basis for the research and development of heavy-duty vehicle tires, and has important practical value and promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is a flow chart of a method according to a specific implementation mode of the present invention.

[0020] Figure 2 It is a schematic diagram of the location of temperature measuring holes on the tire tread according to a specific embodiment of the present invention.

[0021] Figure 3 It is a schematic diagram of the locations of temperature measuring holes on the tread of other pattern tires according to a specific embodiment of the present invention.

[0022] Figure 4 It is a linear regression fitting diagram of high temperature resistance test of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in 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 should fall within the scope of protection of the present invention.

[0024] Example 1 Combination Figure 1 The present invention provides a reliability evaluation method for a heavy-duty automobile tire under high temperature and heavy-load harsh operating conditions, comprising the following steps: 1. A logistics fleet was selected for investigation. The vehicle model is 6×4 / 4×2 tractor, the vehicle operating environment temperature is about 38℃, the average load of a single tire is about 3.55t, the road conditions are mainly good road conditions such as highways and national highways, the average speed is about 80km / h, the monthly mileage is about 30,000 kilometers, express delivery, people stop and stop during operation, and the use of B tires with longitudinal patterns often causes shoulder air blowouts in the middle and late stages, which makes customers very dissatisfied.

[0025] 2. Test the high temperature resistance of tires Select tire a and tire b (original tire) and drill holes in the tread pattern to measure the temperature. Tire a has the same longitudinal pattern as tire b. Figure 2 , the temperature measuring hole is located in the center of the longitudinal tread block, Figure 2 The black dots are temperature measuring holes, the number is 5, the diameter of the temperature measuring holes is 5mm±0.5mm, the depth of the holes is ≤5mm from the top layer of the cord layer, and does not touch the cord layer; if the tire pattern of b is different from that of this embodiment, such as Figure 3The mixed pattern (left) and the engineering block pattern (right) are shown in the figure. Tire a should be selected with the same pattern as tire b, and the position of the temperature measuring holes follows the above principles; the tire is installed on the standard rim and filled with the corresponding air pressure of the maximum single tire load; the tire rim assembly is parked at a temperature of 38±3℃ for 24h; the tire rim assembly is installed on the drum test shaft, and the drum test speed selects 4 test speeds within the highest rated speed of the tire. The test starts from the selected lowest speed, and the ambient temperature during the test is 38±3℃; all temperature measuring holes are numbered, and the temperature of all holes is measured and recorded every 1h of operation until the temperature of all temperature measuring holes remains stable (the temperature of the same point stops rising after 3 consecutive measurements or the difference between the maximum and minimum values ​​of the 3 measurements is less than 3℃), and the test is stopped; the tire is cooled to room temperature and starts running at the next specified speed until the temperature is stable at this speed; the test is carried out until the selected test speed is completed. The specific experimental procedures are shown in Table 1, and the specific experimental data are shown in Table 2.

[0026] Table 1 Tire high temperature resistance test procedure

[0027] Table 2 Tire high temperature resistance test data

[0028] 3. Test the tire's heavy load resistance Select tire a and tire b (original tires) and install the tires on the standard rims specified by the OEM, and inflate them with the corresponding air pressure for the maximum single tire load; measure the main dimensions of the tires after parking for 15 minutes; park the tire-rim assembly at a temperature of 38±3℃ for 3 hours; install the tire-rim assembly on the test shaft and pressurize it vertically to the outer surface of the drum. The test drum should be started to the required test speed (30km / h) with uniform acceleration within 5 minutes. The ambient temperature during the test is 38±3℃, and the number of tested tires is not less than 2; the test is carried out according to the specified conditions, the specified procedures are carried out continuously, and the detection procedures are used according to customary usage, one stage every 10 hours. During the period, it shall not be interrupted, the air pressure shall not be readjusted, and the tire shall not be artificially cooled; the tire is tested according to the specified requirements until the tire has abnormalities such as bulges and blowouts, and the test time shall be ≥60 hours; when the test is carried out for 90 hours and there is no abnormality in the tire, the test is stopped. The specific test procedures are detailed in Table 3.

[0029] Table 3 Tire heavy load performance test procedure

[0030] 4. Data processing and analysis In the high temperature test, the TKPH rating is the product of the load and speed at the highest internal safety temperature (critical temperature), which can be used to evaluate the temperature rise performance of the tire during operation. The TKPH field value is the product of the average load and average speed of a single tire under the vehicle's operating conditions and the temperature correction factor; the temperature correction factor is calculated as follows: when the ambient temperature is greater than 38°C, ; When the temperature correction coefficient = 38℃, the temperature correction coefficient = 1; When the ambient temperature is less than 38℃, When the TKPH rating value is ≥ the TKPH on-site value, the product is considered to be excellent in high temperature resistance, which can ensure the normal operation of the tire. Table 3 shows the temperature correction coefficient calculation data under various ambient temperatures.

[0031] Table 3 Calculation data of temperature correction coefficient at various ambient temperatures

[0032] The heavy load resistance test simulates the continuous operation of the tire under heavy load conditions. During the test, the tire shoulders and tire rims are subjected to great force, which can well simulate the shoulder and tire rim phenomena that occur during actual heavy load use. When the total continuous operation time is ≥60h, it is positioned as a qualified product, and when the total continuous operation time is ≥90h, it is positioned as an excellent heavy load resistance product.

[0033] In the hot summer, the tire temperature is extremely high when the vehicle is running continuously. To ensure the safe operation of the vehicle, the critical temperature is set at 90℃, the ambient temperature is 38±3℃, and the temperature correction coefficient is 1. According to the temperature of the tire after balance at each speed stage in the high temperature test procedure, the TKPH temperature linear regression fitting is made. For details, see Figure 4 , we get the regression equation of tire a y=6.0418x-237.29, and the regression equation of tire b y=6.7403x-355.27. Calculated at 90℃, the TKPH rating of tire a is 306t·km / h, and the TKPH rating of tire b is 251t·km / h. The on-site value of TKPH = 3.55×80×1 = 284t·km / h.

[0034] Tires used in harsh working conditions of high temperature and heavy load are not only required to have good high temperature resistance, but also good heavy load resistance. Through the above analysis, the double-excellent products that are excellent in the screening test are equipped for vehicles under this working condition (see Table 4 for the specific screening procedures). It can be seen from the table that the heavy load resistance of tires a and b are both excellent, among which tire a is a double-excellent product, and tire b (the original tire) has poor high temperature resistance, and the TKPH rating value is less than the TKPH on-site value. This can also explain why tire b has shoulder air blowout in the middle and late stages of use in the logistics fleet. After the logistics fleet used tire a instead of tire b, no shoulder air blowout was found, and the customer feedback was good. This shows that using this method to screen tires can improve the continuous operation capability of tires, ensure operational safety, reduce the time for tire replacement and vehicle maintenance, and improve operational efficiency.

[0035] Table 4 Specific tire screening procedures

[0036] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A reliability evaluation method for heavy-duty vehicle tires under high temperature, heavy load and harsh operating conditions, characterized in that: Through high temperature resistance test and heavy load resistance test to simulate the high temperature and heavy load conditions during the use of tires, the reliability of tires under high temperature and heavy load conditions is evaluated, and tires with excellent high temperature resistance and heavy load resistance are analyzed and selected for installation; The methods for high temperature resistance testing include: (a1) drilling holes at the tire tread to obtain temperature measuring holes, and mounting the tire on a standard rim to obtain a tire-rim assembly; (a2) The tire-rim assembly is mounted on a drum test shaft, and at least four speeds within the highest rated speed of the tire are selected as test speeds. The drum test is carried out at each test speed in sequence starting from the lowest test speed until all selected test speeds are tested or the tire begins to be damaged; the method for carrying out the test at each test speed is to test the temperature in the temperature measuring hole every 1 hour of operation until the temperature of the temperature measuring hole remains stable, record the temperature value at the test speed as the equilibrium temperature value, and stop the test; (a3) Calculate the TKPH value at each test speed, and use the TKPH value at each test speed as y and the equilibrium temperature value as x to fit a linear regression fitting equation y=f(x). Calculate the TKPH rated value of the tire at the critical temperature based on y=f(x). If the TKPH rated value of the tire is ≥ the TKPH on-site value, the high temperature resistance performance of the tire is judged to be excellent. The methods for heavy load resistance testing include: (b1) Mounting the tire on a standard rim to obtain a tire-rim assembly, and inflating the tire to an air pressure corresponding to the maximum single tire load; (b2) The tire-rim assembly is mounted on the test drum shaft, ensuring that the tire is vertical and in close contact with the outer surface of the drum. Pressure is applied and the drum is started. If there is no abnormality in the tire when the test time reaches 60 hours, the tire's heavy load resistance performance is judged to be qualified. If there is no abnormality in the tire when the test time is ≥ 90 hours, the tire's heavy load resistance performance is judged to be excellent.

2. The reliability evaluation method for heavy-duty vehicle tires under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (a1), the number of the temperature measuring holes is at least four, each of which is drilled at the center of the pattern, has a diameter of 5±0.5 mm, and a distance between the bottom of the temperature measuring hole and the topmost cord layer is ≤5 mm.

3. The reliability evaluation method for heavy-duty vehicle tires under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (a1), the tire-rim assembly is placed in an environment with a temperature of 38±3°C for 24 hours.

4. The reliability evaluation method of a heavy-duty vehicle tire under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (a2), when four test speeds are selected, the test speeds are 0.5V, 0.67V, 0.83V, and V, respectively, where V is the maximum rated speed of the tire.

5. The reliability evaluation method of a heavy-duty vehicle tire under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (a2), the condition for the temperature of the temperature measuring hole to remain stable is that the temperature of the same temperature measuring hole stops rising after three consecutive measurements, or the difference between the maximum and minimum values ​​of the three temperature measurements is less than 3°C.

6. The reliability evaluation method for heavy-duty vehicle tires under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (a1), the tire is inflated to an air pressure corresponding to the maximum single tire load; in step (a2), pressure is applied to the tire, and the tire load is set to 80% to 90% of the maximum rated load of the tire.

7. The reliability evaluation method for heavy-duty vehicle tires under high-temperature, heavy-load and severe operating conditions according to claim 6 is characterized in that: The calculation method of TKPH value = tire load × test speed.

8. The reliability evaluation method for heavy-duty vehicle tires under high-temperature, heavy-load and severe operating conditions according to claim 6 is characterized in that: TKPH field value = average load under working conditions × average speed under working conditions × temperature correction coefficient; the calculation method of temperature correction coefficient is: when the ambient temperature is greater than 38℃, ; When the ambient temperature = 38℃, the temperature correction coefficient = 1; When the ambient temperature < 38℃, .

9. The reliability evaluation method of a heavy-duty vehicle tire under high-temperature, heavy-load and severe operating conditions according to claim 1 is characterized in that: In step (b2), a pressure of 180% to 200% of the maximum rated load of the tire is applied to the tire; after the drum is started, the speed is uniformly accelerated to 10 to 30 km / h within 5 minutes.

10. The reliability evaluation method of a heavy-duty vehicle tire under high-temperature, heavy-load and severe operating conditions according to claim 1, characterized in that: In step (b2), the abnormal condition includes tire bulging and / or tire blowout.

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