Design method for rolling resistance of low-rolling-resistance truck radial tire

Abstract

The invention discloses a low-rolling-resistance truck radial tire and a design method thereof, a 0-degree nylon cord thread reinforcing layer with the thickness of 1.0-2.0 mm is additionally arranged between a second belted layer and a third belted layer of the tire, and the material distribution of the belted layers is optimized. The design method comprises the steps of determining basic parameters of the tire, determining parameters of the reinforcing layer through mechanical calculation and simulation, optimizing material distribution of the belted layer through finite element analysis, and verifying and optimizing through a laboratory and an actual road test. Through tests, compared with a traditional tire, the rolling resistance coefficient of the tire is averagely reduced by 20.2%, the wear resistance is improved by 22.6%, under different road conditions such as flat, bumpy, wet and slippery conditions and muddy conditions, the abrasion loss is reduced, the oil consumption is reduced, the braking distance is shortened, the escape time is shortened, the comprehensive performance of the tire is effectively improved, and the vehicle energy consumption and the operation cost are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tire technology, in particular to a design method of low rolling resistance of a low rolling resistance truck and bus radial tire. BACKGROUND

[0002] Under the background of global energy crisis and increasing environmental protection awareness, the energy saving and emission reduction work of the transportation industry, as an important field of energy consumption and carbon emission, has attracted much attention. Truck vehicles, as the main force of logistics transportation, are widely used in cargo transportation scenarios, but their high energy consumption and high emission problems are prominent. According to statistics, the energy consumption caused by tire rolling resistance accounts for about 20%-30% of the fuel consumption of truck vehicles, so reducing the rolling resistance of truck tires has become a key breakthrough to reduce vehicle fuel consumption and carbon emissions, and is also an important research direction for the tire manufacturing industry to achieve green and sustainable development.

[0003] At present, the truck and bus radial tires widely used in the market have obvious shortcomings in rolling resistance control. In the structural design of traditional truck and bus radial tires, the crown force distribution is not scientific and reasonable. During vehicle driving, the tire crown will be subjected to complex forces from the road surface, including vertical pressure, friction and shear force, etc. Unreasonable force distribution causes large deformation of the tire in the circumferential direction. This excessive circumferential deformation will cause the contact state between the tire and the ground to be unstable, increase the hysteresis loss of the tire internal rubber and cord materials, and thus increase the rolling resistance. For example, under long-distance high-speed driving conditions, the energy loss caused by the circumferential deformation of traditional truck and bus radial tires will increase the fuel consumption of the vehicle by 1-1.5L per 100 kilometers, which not only increases the logistics transportation cost, but also aggravates energy consumption and environmental pollution.

[0004] In order to solve the problem of high rolling resistance of traditional truck and bus radial tires, many researches and attempts have been made in the industry. Some enterprises and research institutions try to reduce the rolling resistance by improving the rubber formula, such as adding special rubber additives and using new rubber materials, in an attempt to improve the hysteresis performance of rubber. However, due to the limitations of the performance of rubber materials, simply relying on the improvement of rubber formula can only reduce the rolling resistance by a limited amount, usually only 5%-10%, which cannot meet the increasingly stringent energy saving standards and market demand. Some technologies also try to optimize tire performance by adjusting the cord structure, such as changing the cord angle and increasing the number of cord layers, but these improvement measures often have negative effects on other tire performance, such as reducing the flexibility of the tire and increasing the weight of the tire, which will affect the handling performance and fuel economy of the vehicle, and cannot achieve the balance between rolling resistance reduction and comprehensive performance improvement of the tire.

[0005] Therefore, a design method of low rolling resistance of a low rolling resistance truck and bus radial tire is provided, which can eliminate the drawbacks of the existing device. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for designing the rolling resistance of a low-rolling-resistance load-bearing radial tire, thereby solving the problem of inconvenience in use in the prior art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A low rolling resistance load-bearing radial tire comprises a carcass, a belt layer, and a tread. The belt layer comprises a multi-layer structure, and a nylon cord reinforcement layer with a 0° angle is provided between the second and third belt layers. The thickness of the nylon cord reinforcement layer is 1.0-2.0 mm. The material distribution of the belt layers is optimized. The belt layer near the tread is made of high-strength, high-modulus material, while the belt layer near the carcass focuses on bonding strength and flexibility with the carcass.

[0009] On the basis of the above technical solutions, the present invention also provides the following optional technical solutions:

[0010] In an optional solution: the high-strength, high-modulus material is aramid cord or steel cord.

[0011] In an optional solution, the belt layer material close to the carcass is polyester cord.

[0012] In an optional solution, the second belt layer and the third belt layer use steel cords, and the cord angles are opposite to each other.

[0013] A method for designing a low rolling resistance load-bearing radial tire comprises the following steps:

[0014] Step 1: Determine the basic parameters of the tire: Determine the tire size, rated load, and speed level based on the target vehicle's load requirements, driving speed, and road conditions;

[0015] Step 2: Design of nylon cord reinforcement layer: Based on the tire structural characteristics and stress analysis, select nylon cord with a 0° angle as the reinforcement material. Through mechanical calculation and simulation analysis, determine the thickness of the reinforcement layer to be between 1.0-2.0mm, and design the connection method between the reinforcement layer and the second and third belt layers.

[0016] Step 3: Optimize belt material distribution: Use finite element analysis to simulate the stress conditions of the tire under different operating conditions, analyze the stress distribution pattern of each belt layer, and adjust the type, thickness, and cord angle parameters of each belt layer based on the analysis results to achieve optimal material distribution;

[0017] Step four: performance verification and optimization: make tire samples, detect the rolling resistance, wear resistance, fatigue resistance of the tire through laboratory test and actual road test, and optimize and adjust the design parameters according to the test results.

[0018] In an alternative, in the step of determining the basic parameters of the tire, when the target vehicle is a heavy truck, the tire specification is 12.00R20, the rated load is 3500kg, and the speed level is L level.

[0019] In an alternative, in the step of designing the nylon cord reinforcing layer, a special rubber adhesive is used to realize the firm combination of the reinforcing layer and the second belt layer and the third belt layer.

[0020] Compared with the prior art, the low rolling resistance truck and bus radial tire and the design method have the following beneficial effects:

[0021] The low rolling resistance truck and bus radial tire and the design method have the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a structural schematic diagram of the present application.

[0023] Marked with the following figure:

[0024] Inner liner 1, carcass 2, first belt layer 3, second belt layer 4, third belt layer 5, fourth belt layer 6, tread 7, belt layer type glue 8, shoulder pad glue 9, tire side 10, nylon cord reinforcing layer 11. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0026] Embodiment of low rolling resistance truck and bus radial tire

[0027] I. Manufacturing of low rolling resistance truck and bus radial tire

[0028] The low rolling resistance truck and bus radial tire comprises, from inside to outside, an inner liner 1, a carcass 2, a first belt layer 3, a second belt layer 4, a third belt layer 5, a fourth belt layer 6, a tread 7, a belt layer type rubber 8, a shoulder pad rubber 9, and a sidewall 10. The second belt layer 4 and the third belt layer 5 are provided with a nylon cord reinforcing layer 11 therebetween.

[0029] (I) Carcass manufacturing

[0030] High-strength polyester cords are selected as the carcass cord material, with a cord specification of 1870 dtex. The polyester cords are compounded with unvulcanized rubber through a cord calendering process to produce the carcass cord fabric. Taking a 12.00R20 size tire as an example, the carcass cord fabric width is set to 1200 mm, and the cord angle is 90°, ensuring that the carcass can withstand the internal inflation pressure and external load of the tire, laying a foundation for subsequent performance.

[0031] (II) Belt layer and nylon cord reinforcing layer manufacturing

[0032] 1# Belt layer manufacturing: aramid cords are used as the material, with a cord specification of 1500 dtex. The belt layer winding equipment is used to wind 2 layers of cords at a cord angle of 20°, with the belt layer thickness controlled at 0.8 mm. This structure design enables the 1# belt layer to effectively disperse stress from the tread and protect the carcass, and its performance will be reflected in the subsequent overall tire performance.

[0033] Second belt layer manufacturing: steel wire cords (specification Φ0.35 mm) are selected, and 3 layers of cords are wound at a cord angle of 15°, with a thickness of 1.0 mm. The high strength and high modulus characteristics of the steel wire cords enhance the rigidity of the tire crown, which is one of the key structures for achieving low rolling resistance and high wear resistance and other performances.

[0034] Nylon cord reinforcing layer manufacturing: nylon cords with a specification of 2000 dtex and an angle of 0° are selected and cut into appropriate sizes by a special cord cutting device. A special rubber adhesive (made by mixing styrene-butadiene rubber, phenolic resin, and accelerators in proportion) with a thickness of 0.1 mm is uniformly coated on both sides of the nylon cord fabric using a gluing process, and then laid on top of the second belt layer with a thickness of 1.5 mm. This reinforcing layer plays a key role in reducing rolling resistance and enhancing crown stability in subsequent performance tests.

[0035] 3# Belt layer manufacturing: similarly, steel wire cords with a specification of Φ0.35 mm are used, and 3 layers of cords are wound at a cord angle of -15°, with a thickness of 1.0 mm. This forms an interlaced structure with the second belt layer, further enhancing the stability of the tire crown.

[0036] Near the carcass belt production: polyester cord (specification 1260dtex), with a cord angle of 85°, 2 layers, thickness 0.6mm, to ensure good bonding strength and flexibility with the carcass.

[0037] (Three) tire tread production

[0038] According to the tire use conditions and performance requirements, the design of the tread rubber formula. Select natural rubber, butadiene rubber, carbon black, white carbon black, accelerator and other raw materials according to the specific proportion of mixing, mixing by mixing machine and open mill into the tread rubber. The tread rubber is extruded into a shape on the tread extruder, the tread width is 380mm, the thickness is 20mm, the deep longitudinal pattern design is adopted, the pattern depth is 18mm, to improve the grip and wear resistance.

[0039] (Four) tire molding and vulcanization

[0040] On the tire building machine, according to the order of carcass-belt-tread, the assembly is pasted in turn to ensure the accurate position of each part and the close fit. The molded tire is placed in the vulcanizing machine at a temperature of 165℃ and a pressure of 1.5MPa for 40 minutes to fully crosslink the rubber of each part of the tire and form a stable structure and performance of the tire product.

[0041] II. Implementation of the design method of low-rolling-resistance truck and bus radial tire

[0042] (I) Determine the basic parameters of the tire

[0043] According to the transportation requirements of a heavy truck, the factors such as the curb weight, maximum load, common driving speed and main driving conditions are comprehensively analyzed to determine the tire specification as 12.00R20, the rated load as 3500kg and the speed level as L level (the highest design speed of 120km / h) to set the standard for the subsequent design and performance test.

[0044] (II) Design of nylon cord reinforcing layer

[0045] A three-dimensional model of the tire is established by using the finite element analysis software ANSYS to simulate the stress of the tire under different conditions. By changing the thickness parameters of the nylon cord reinforcing layer (1.0mm, 1.2mm, 1.5mm, 1.8mm, 2.0mm), the crown stress distribution and deformation of the tire are calculated. The data shows that when the thickness is 1.5mm, the crown stress concentration is significantly improved and the circumferential deformation is the smallest, so the optimal thickness of the reinforcing layer is determined. At the same time, a special rubber adhesive is used to ensure the firm connection between the reinforcing layer and the second and third belt layers, and to ensure the effective transmission of stress.

[0046] (III) Optimization of belt material distribution

[0047] The finite element analysis method is used to comprehensively simulate the stress of the tire under different working conditions such as high-speed driving, emergency braking, turning, and driving on bumpy road. The stress distribution law of each belt layer under different working conditions is analyzed, and the type, thickness, and cord angle parameters of each layer of belt layer material are adjusted accordingly. For example, under high-speed driving conditions, the thickness and cord strength of the 1# belt layer close to the tread are increased; under bumpy road driving conditions, the flexibility parameters of the belt layer material close to the tire body are optimized to achieve optimal distribution of the belt layer material and improve the overall performance of the tire.

[0048] (IV) Performance verification and optimization

[0049] Laboratory tests

[0050] Rolling resistance test: FTT-1000 type rolling resistance tester is used to test under different speed and load conditions according to ISO28580 standard. The data shows that when the speed is 60 km / h and the load is 2500 kg, the rolling resistance coefficient of the tire is 0.0062, and that of the traditional tire is 0.0078, with a decrease of 20.5%; when the speed is 80 km / h and the load is 3000 kg, the rolling resistance coefficient of the tire is 0.0068, and that of the traditional tire is 0.0085, with a decrease of 20%; when the speed is 100 km / h and the load is 3500 kg, the rolling resistance coefficient of the tire is 0.0075, and that of the traditional tire is 0.0094, with a decrease of 20.2%, and the average decrease is 20.2%, fully proving the low rolling resistance property.

[0051] Wear resistance test: the wear test machine is used to test under the conditions of test time 24 hours, drum speed 80 km / h, load 3000 kg, and temperature 25℃. The wear volume of the tire is 120\(cm^3\), and that of the traditional tire is 155\(cm^3\), the wear resistance of the tire is improved by 22.6%, which shows that the service life can be effectively prolonged.

[0052] Fatigue resistance test: in the fatigue test, the tire is subjected to cyclic loading (10 million cycles, load range 2000-3500 kg) to simulate the actual driving stress. After the test, the tire does not show obvious fatigue damage such as cord rupture and rubber cracking, while the traditional tire shows 3 places of local cord rupture and fine cracks on the rubber surface. The anti-fatigue performance of the tire is obviously better, and it can adapt to long-term heavy load driving.

[0053] Actual road test

[0054] Flat road: after driving 8000 kilometers on the target heavy truck, the average wear thickness of the tire tread is 1.8 mm, and that of the traditional tire is 2.3 mm, the wear of the tire is reduced by 21.7%; the fuel consumption per 100 kilometers of the vehicle is 42L for the tire and 43.5L for the traditional tire, the fuel consumption of the tire is reduced by 3.4%, verifying the energy saving effect of low rolling resistance.

[0055] Bumpy road: After driving 4000km, the tread of the tire is slightly worn, with a maximum wear difference of 0.3mm, and no cord damage; the traditional tire has local abnormal wear, with a maximum wear difference of 0.8mm, and 1 place of cord slight damage. The anti-wear and anti-damage capabilities of the tire are significantly superior.

[0056] Wet road: After driving 3000km on a simulated rainy wet road, 10 emergency braking tests were conducted, the average braking distance of the tire was 28.5m, and that of the traditional tire was 31.2m. The tire braking distance was shortened by 8.7%. In the wet curve driving test, the lateral slip amount of the tire was 5cm on average, and that of the traditional tire was 8cm. The handling stability and safety of the tire on the wet road were greatly improved.

[0057] Muddy road: After driving 5000km, the tire was only slightly scratched once, and there was no puncture; the traditional tire had 3 scratches and 1 slight puncture, and the average escape time of the tire on the muddy road was shortened by 30% compared with the traditional tire, and the passability and durability were stronger.

[0058] According to the laboratory test and actual road test results, the tire structure design and material parameters are further optimized and adjusted to ensure that the tire meets or exceeds the design expected effect in terms of rolling resistance, wear resistance, fatigue resistance and adaptability to different road conditions.

[0059] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A low rolling resistance load-bearing radial tire, characterized by: It includes a carcass, a belt layer and a tread. The belt layer is composed of a multi-layer structure. A nylon cord reinforcement layer with an angle of 0° is provided between the second belt layer and the third belt layer. The thickness of the nylon cord reinforcement layer is 1.0-2.0mm. The material distribution of the belt layer is optimized. The belt layer close to the tread adopts high-strength and high-modulus materials, and the belt layer close to the carcass focuses on the bonding strength and flexibility with the carcass.

2. The low rolling resistance load-bearing radial tire according to claim 1, characterized in that: The high-strength, high-modulus material is aramid cord or steel cord.

3. The low rolling resistance load-bearing radial tire according to claim 1, characterized in that: The belt material close to the carcass is polyester cord.

4. The low rolling resistance load-bearing radial tire according to claim 1, characterized in that: The second belt layer and the third belt layer are made of steel cords, and the cord angles are opposite to each other.

5. A method for designing a low rolling resistance load-bearing radial tire according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Determine the basic parameters of the tire: Determine the tire size, rated load, and speed level based on the target vehicle's load requirements, driving speed, and road conditions; Step 2: Design of nylon cord reinforcement layer: Based on the tire structural characteristics and stress analysis, select nylon cord with a 0° angle as the reinforcement material. Through mechanical calculation and simulation analysis, determine the thickness of the reinforcement layer to be between 1.0-2.0mm, and design the connection method between the reinforcement layer and the second and third belt layers. Step 3: Optimize belt material distribution: Use finite element analysis to simulate the stress conditions of the tire under different operating conditions, analyze the stress distribution pattern of each belt layer, and adjust the type, thickness, and cord angle parameters of each belt layer based on the analysis results to achieve optimal material distribution; Step 4: Performance Verification and Optimization: Produce tire samples and test the tire's rolling resistance, wear resistance, and fatigue resistance through laboratory tests and actual road tests. Optimize and adjust the design parameters based on the test results.

6. The design method of a low rolling resistance load-bearing radial tire according to claim 5, characterized in that: In the step of determining basic tire parameters, when the target vehicle is a heavy truck, the tire specification is 12.00R20, the rated load is 3500kg, and the speed level is L.

7. The design method of a low rolling resistance load-bearing radial tire according to claim 5, characterized in that: In the nylon cord reinforcement layer design step, a rubber adhesive is used to achieve a firm bond between the reinforcement layer and the second belt layer and the third belt layer.

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