Method for improving abnormal deformation of side wall of bias tire

Abstract

The invention belongs to the technical field of tire simulation and tire structure design, and discloses a method for improving abnormal deformation of the side wall of a bias tire, which comprises a steel wire ring, apex, a fiber cord fabric layer and a tire body cord fabric layer, the steel wire ring, the apex, the fiber cord fabric layer and the tire body cord fabric layer jointly form a lower part of the tire, the method comprises the following specific steps: step 1, determining an improvement target and a tire specification, determining a specific target for improving the abnormal deformation of the side wall of the bias tire, and selecting the tire specification needing to be improved; according to the invention, the number of existing steel wire rings does not need to be increased to 3-4, so that the unnecessary extra increase of the production cost of the steel wire rings and the tire body cord is reduced, and the difficulty of a forming process is far lower than that of a scheme of 3-4 steel wire rings; only a single-layer fiber cord thread layer is used, so that the production cost is low, and the risk of heat generation and delamination is low; according to the fiber cord layer, the problem that the rigidity is insufficient due to the fact that only the fiber cord layer is arranged on the inner side is solved through the process of reversely wrapping the steel wire ring.

Description

Technical Field

[0001] This invention belongs to the field of tire simulation and tire structure design technology, specifically a method for improving abnormal deformation of the sidewall of a bias-ply tire. Background Technology

[0002] Engineering tires are typically used in large machinery, such as mining trucks or loaders, which operate in harsh environments with heavy loads. Sidewall deformation is one of the common failure problems of engineering tires, directly affecting tire life and safety.

[0003] A search revealed several existing technologies for improving tire sidewall deformation: CN215793009U: Improving the strength of the lower tire sidewall and increasing tire lifespan by filling the area between the outer and inner ply structures with a serrated rubber sheet; CN101758748A: A ply layer containing multiple steel wire rings, with each ring wrapped in reverse, and a ply fiber layer within the carcass ply layer to reduce carcass tensile deformation caused by internal pressure, increasing cushioning performance during rolling, thereby improving durability; CN120310069A: Adjusting the sidewall rubber composition and preparation method to improve the sidewall rubber's flexural strength and deformation resistance; CN1133 88174A: Improves the hardness of the sidewall compound, reaching over 65 degrees, increasing the tire sidewall's resistance to deformation by over 30%; CN116120643A: Improves the performance of the sidewall compound, achieving the goal of making the sidewall less susceptible to scratches and reducing the rate of cut wounds without adding reinforcing ribs. However, the above solutions still have shortcomings: the number of steel wire rings is relatively large, resulting in a significant increase in the number of carcass ply layers, increasing production costs and molding process difficulty; the large number of fiber ply layers increases production costs and increases the risk of heat-induced delamination; the fiber ply layers do not wrap around the steel wire rings, resulting in lower sidewall stiffness lower than solutions that do wrap around the steel wire rings. Summary of the Invention

[0004] The purpose of this invention is to provide a method for improving abnormal sidewall deformation in bias-ply tires, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for improving abnormal sidewall deformation of a bias-ply tire, comprising a steel wire bead, a triangular rubber, a fiber ply, and a carcass ply, wherein the steel wire bead, triangular rubber, fiber ply, and carcass ply together constitute the lower part of the tire, and the specific steps of the method are as follows: Step 1: Determine the improvement goals and tire specifications Determine the specific goals for improving the abnormal sidewall deformation of bias-ply tires and select the tire specifications that need to be improved (engineering tires 23.5-25). Step Two: Determining the Benchmark Design Scheme and Reproducing Failure Symptoms Select a baseline design scheme and reproduce the failure symptoms of abnormal deformation of the tire sidewall through simulation; Step 3: Design of Triangular Rubber Height Adjustment Scheme Based on tire specifications and usage conditions, set the adjustment range for the height of the triangular rubber and design an adjustment plan; Step 4: Optimization of tire cord angle and arrangement density Based on the baseline design, the tire carcass cord angle and arrangement density are adjusted to improve tire sidewall stiffness; Step 5: Fiber Cord Layer Design A single-layer fiber curtain design was adopted, and its laying method, position, and angle were determined; Step Six: Simulation Analysis and Scheme Comparison Establish a simulation model, conduct simulation analysis on multiple improvement schemes of the design, and select the optimal scheme; Step 7: Trial Production and Preliminary Testing The improved solution selected through simulation was put into trial production and preliminary testing and verification were conducted. Step 8: Vehicle Testing The prototype tire was installed on an actual vehicle for full vehicle testing. Then, under the same operating conditions, the sidewalls of the improved tire were observed for any wrinkles.

[0006] As a preferred embodiment of the present invention, in step one, the height range of the outer triangular rubber of the tire, H1-H1', is 60-85mm; the height range of the inner triangular rubber of the tire, H2-H2', is 50-75mm; the fiber cord layer is a single-layer cord with an angle range of 25-35°; the laying directions on the left and right sides of the fiber cord layer are " / " and "\" respectively; the angle range of the carcass cord layer is 25-35°, and the center spacing between the two cords of the carcass cord layer is not less than 1.25mm.

[0007] As a preferred technical solution of the present invention, in the reference solution described in step two, the design parameters of the reference solution are used as the reference, and the height of the inner / outer triangular rubber of the tire is 100% / 100%, the tire cord angle is 100%, and the tire cord arrangement density is 100%.

[0008] As a preferred technical solution of the present invention, the specific steps for simulating and reproducing the failure symptoms in step two are as follows: Establish a high-precision tire simulation model: Based on the actual tire specifications (23.5-25 engineering tire), construct a three-dimensional geometric model in CAE software, including key components such as the tire carcass ply, triangular rubber, steel wire bead, and fiber ply; input the material parameters of each component, define the hardness, density, and bonding strength of the triangular rubber with the ply; use a fine mesh for the sidewall area, and use shell elements or beam elements to simulate the composite behavior of fiber and metal in the ply and steel wire bead areas; Set boundary conditions and operating parameters: Define the friction coefficient and contact stiffness between the tire and the ground to simulate the lateral force during steering; constrain the axial and radial displacement of the steel wire ring to simulate the actual installation state; set the tire inflation pressure (300kPa) and apply a single tire vertical load (9500kg) to simulate the torsional deformation when turning 5° in place. Simulating the sidewall deformation mechanism: By rotating the rim or applying torque, the shear and bending deformation of the sidewall during steering is simulated, focusing on the stress distribution in the lower sidewall region (the junction of the triangular rubber and the cord layer); using common node or embedded element technology, the slippage and delamination behavior of the cord and rubber are simulated, and the contribution of cord angle and arrangement density to the sidewall stiffness is observed. Failure Symptom Reproduction and Verification: Extract the maximum principal strain cloud map of the tire sidewall, identify the starting position and expansion path of the "twisted" deformation, compare the deformation mode of the baseline scheme (Case 0) with that of the actual failed tire, and verify the accuracy of the simulation.

[0009] As a preferred technical solution of the present invention, the specific content of the triangular rubber height adjustment scheme design in step three is as follows: combined with tire specifications and usage conditions, the range of the outer triangular rubber height H1-H1' is set to 60-85mm, and the range of the inner triangular rubber height H2-H2' is set to 50-75mm; an adjustment scheme with different height combinations is designed, including gradually increasing the height of the inner and outer triangular rubbers.

[0010] As a preferred technical solution of the present invention, the optimization of the tire cord angle and arrangement density in step four is as follows: based on the tire cord angle of the benchmark scheme, an angle adjustment scheme is designed: gradually increasing from 100% to 106%; combined with the angle adjustment results, the arrangement density of the tire cord is optimized: increasing from 100% to 109%.

[0011] As a preferred technical solution of the present invention, the specific content of the fiber cord layer design in step five is as follows: a single-layer fiber cord layer design is adopted, and the left and right sides are laid in the manner of " / " and "\"; the fiber cord layer needs to wrap around the steel wire ring, and the angle range is set to 25-35°. The optimal laying angle is determined through simulation analysis to maximize the improvement of tire sidewall stiffness.

[0012] As a preferred technical solution of the present invention, the simulation analysis and scheme comparison in step six specifically includes: establishing a tire simulation model based on the finite element analysis method, including the adjusted height of the triangular rubber, the tire carcass cord angle and arrangement density, and the fiber ply parameters, to ensure that the model accurately reflects the mechanical characteristics of the actual tire; performing simulation analysis on the three designed improvement schemes, simulating the same operating conditions, and comparing the tire carcass cord deformation, sidewall stiffness, and stress distribution key indicators of each scheme; and selecting the scheme with the most significant improvement effect as the preferred scheme based on the simulation analysis results.

[0013] As a preferred technical solution of the present invention, the specific content of the trial production and preliminary testing in step seven is as follows: according to the design parameters of the preferred solution, an improved tire sample is produced; the trial tire is subjected to preliminary testing in a laboratory or testing site, including static loading test and dynamic driving test, and the test data and phenomena are recorded.

[0014] The beneficial effects of this invention are as follows: This invention eliminates the need to increase the number of steel wire rings from two to three or four, reducing unnecessary additional costs associated with steel wire ring and tire cord production. The molding process is significantly less complex than the three-to-four steel wire ring solution. Using only a single layer of fiber cord results in low production costs and a low risk of heat-induced delamination. The fiber cord layer of this invention compensates for insufficient stiffness by wrapping it over the steel wire ring, overcoming the problem of insufficient stiffness when only a fiber cord layer is placed on the inner side. This invention has a simple structure, lower production costs, and a lower production difficulty coefficient. By proposing improvements not addressed in existing solutions (increasing the height of the triangular rubber, increasing the angle and density of the tire cord), it enhances the stiffness of the lower tire sidewall and its resistance to deformation, eliminating abnormal "twisted" deformation of the tire sidewall during use. Attached Figure Description

[0015] Figure 1 This is a flowchart of the present invention; Figure 2 This is a material distribution diagram of the lower half of the tire of the present invention; Figure 3 This is a schematic diagram showing the height of the triangular adhesive of the present invention; Figure 4 This is a photograph of the actual object showing the abnormal "twisted" deformation of the tire sidewall of the present invention. Figure 5 The baseline scheme of this invention is used to simulate and reproduce the abnormal "twisted" deformation diagram of the tire sidewall; Figure 6 This is a simulation diagram of abnormal deformation of the tire cord in the baseline scheme of this invention; Figure 7 This is a simulation result of the maximum principal strain of the tire cord in this invention; Figure 8 This is a prototype image of the improved tire sidewall according to the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] like Figures 1 to 8 As shown, this embodiment of the invention provides a method for improving abnormal sidewall deformation of a bias-ply tire, comprising a steel bead, a triangular rubber, a fiber ply, and a carcass ply. The steel bead, triangular rubber, fiber ply, and carcass ply together constitute the lower part of the tire. The specific steps of the method are as follows: Step 1: Determine the improvement goals and tire specifications Determine the specific goals for improving the abnormal sidewall deformation of bias-ply tires and select the tire specifications that need to be improved (engineering tires 23.5-25). Step Two: Determining the Benchmark Design Scheme and Reproducing Failure Symptoms Select a baseline design scheme and reproduce the failure symptoms of abnormal deformation of the tire sidewall through simulation; Step 3: Design of Triangular Rubber Height Adjustment Scheme Based on tire specifications and usage conditions, set the adjustment range for the height of the triangular rubber and design an adjustment plan; Step 4: Optimization of tire cord angle and arrangement density Based on the baseline design, the tire carcass cord angle and arrangement density are adjusted to improve tire sidewall stiffness; Step 5: Fiber Cord Layer Design A single-layer fiber curtain design was adopted, and its laying method, position, and angle were determined; Step Six: Simulation Analysis and Scheme Comparison Establish a simulation model, conduct simulation analysis on multiple improvement schemes of the design, and select the optimal scheme; Step 7: Trial Production and Preliminary Testing The improved solution selected through simulation was put into trial production and preliminary testing and verification were conducted. Step 8: Vehicle Testing The prototype tire was installed on an actual vehicle for full vehicle testing. Then, under the same operating conditions, the sidewalls of the improved tire were observed for any wrinkles.

[0018] By increasing the height of the triangular rubber and increasing the angle and density of the tire cords, the stiffness of the lower tire sidewall is improved, thereby enhancing the sidewall's resistance to deformation. This can eliminate abnormal "twisted" deformation of the tire sidewall during use. This solution is not limited to the tire specifications mentioned above, but is also applicable to improving abnormal sidewall deformation of other specifications of bias-ply tires.

[0019] In step one, the height range of the outer triangular rubber on the tire (H1-H1') is 60-85mm; the height range of the inner triangular rubber on the tire (H2-H2') is 50-75mm; the fiber cord layer is a single layer of cord with an angle range of 25-35°; the laying directions on the left and right sides of the fiber cord layer are " / " and "\" respectively; the angle range of the carcass cord layer is 25-35°, and the center spacing between the two cords of the carcass cord layer is not less than 1.25mm.

[0020] Market feedback indicates that engineering tires in the 23.5-25 size, operating under conditions of 300 kPa and a single tire load of 9500 kg, exhibit abnormal "twisting" deformation on the sidewall when turning 5° from a stationary position. Figure 4 As shown, it is clear that there is an abnormality on the sidewall when turning.

[0021] In step two, the reference scheme uses the design parameters of the reference scheme as a reference. The height of the inner / outer triangular rubber is 100% / 100%, the tire cord angle is 100%, and the tire cord arrangement density is 100%.

[0022] The tires in the benchmark design are engineering tires that have been identified as problematic by the market. Based on the benchmark design, comparative designs are then developed.

[0023] The specific steps for simulating and reproducing the failure symptoms in step two are as follows: Establish a high-precision tire simulation model: Based on the actual tire specifications (23.5-25 engineering tire), construct a three-dimensional geometric model in CAE software, including key components such as the tire carcass ply, triangular rubber, steel wire bead, and fiber ply; input the material parameters of each component, define the hardness, density, and bonding strength of the triangular rubber with the ply; use a fine mesh for the sidewall area, and use shell elements or beam elements to simulate the composite behavior of fiber and metal in the ply and steel wire bead areas; Set boundary conditions and operating parameters: Define the friction coefficient and contact stiffness between the tire and the ground to simulate the lateral force during steering; constrain the axial and radial displacement of the steel wire ring to simulate the actual installation state; set the tire inflation pressure (300kPa) and apply a single tire vertical load (9500kg) to simulate the torsional deformation when turning 5° in place. Simulating the sidewall deformation mechanism: By rotating the rim or applying torque, the shear and bending deformation of the sidewall during steering is simulated, focusing on the stress distribution in the lower sidewall region (the junction of the triangular rubber and the cord layer); using common node or embedded element technology, the slippage and delamination behavior of the cord and rubber are simulated, and the contribution of cord angle and arrangement density to the sidewall stiffness is observed. Failure Symptom Reproduction and Verification: Extract the maximum principal strain cloud map of the tire sidewall, identify the starting position and expansion path of the "twisted" deformation, compare the deformation mode of the baseline scheme (Case 0) with that of the actual failed tire, and verify the accuracy of the simulation.

[0024] During the reproduction and verification of failure symptoms, the amplitude and angle of the sidewall wrinkles in the simulation were measured and compared with those in the figures. Simultaneously, the cord tension and interlaminar shear stress were recorded to determine whether the material fatigue limit was exceeded. Figure 5 and Figure 6 As shown, Figure 5 and Figure 6 The simulation results are shown for the baseline scheme (Case 0).

[0025] The specific details of the triangular rubber height adjustment scheme in step three are as follows: Based on the tire specifications and usage conditions, the range of the outer triangular rubber height H1-H1' is set to 60-85mm, and the range of the inner triangular rubber height H2-H2' is set to 50-75mm; adjustment schemes with different height combinations are designed, including gradually increasing the height of the inner and outer triangular rubbers.

[0026] The potential effect of gradually increasing the height of the inner and outer triangular rubber on improving tire sidewall deformation was evaluated and verified through simulation.

[0027] Specifically, the optimization of the tire cord angle and arrangement density in step four is as follows: Based on the baseline tire cord angle, design an angle adjustment scheme: gradually increase from 100% to 106%; combined with the angle adjustment results, optimize the tire cord arrangement density: increase from 100% to 109%.

[0028] The effect of changing the tire sidewall stiffness and deformation was evaluated through simulation analysis, and the optimal tire sidewall density was determined.

[0029] The specific design of the fiber cord layer in step five is as follows: a single-layer fiber cord layer design is adopted, and the left and right sides are laid in the manner of " / " and "\". The fiber cord layer needs to wrap around the steel wire ring, and the angle range is set to 25-35°. The optimal laying angle is determined through simulation analysis to maximize the improvement of tire sidewall stiffness.

[0030] The overall stability and rigidity of the tire sidewall are improved by laying the tire in a " / " and "\" pattern on both sides; the support of the lower tire sidewall is enhanced by wrapping the fiber cord layer over the steel wire ring.

[0031] The simulation analysis and scheme comparison in step six specifically involves: establishing a tire simulation model based on the finite element analysis method, including the adjusted height of the triangular rubber, the tire carcass cord angle and arrangement density, and the fiber ply parameters, to ensure that the model accurately reflects the mechanical characteristics of the actual tire; conducting simulation analysis on the three designed improvement schemes, simulating the same operating conditions, and comparing the tire carcass cord deformation, sidewall stiffness, and stress distribution of each scheme; and selecting the scheme with the most significant improvement effect as the preferred scheme based on the simulation analysis results.

[0032] The baseline scheme is Case 0. The three improvement schemes are Case 1, Case 2, and Case 3, and the specific designs are shown in the table below. The operating conditions are 300 kPa, 9500 kg, and a 5° turn in place. The simulation results of the tire cord deformation are as follows: Figure 7 As shown, based on the simulation analysis results of the maximum principal strain of the tire cord, Case 3 shows a more significant improvement effect.

[0033] plan Inner / outer triangular rubber height tire cord angle Carcass cord density Remark Initial solution Case 0 100% / 100% 100% 100% Market feedback on problematic tires Improvement Plan Case 1 142% / 135% 100% 100% Increase the height of the triangular rubber based on case 0. Improvement Plan Case 2 142% / 135% 106% 100% Based on case 1, increase the tire cord angle. Improvement Plan Case 3 142% / 135% 106% 109% Increase the density of tire cord arrangement based on case 2. The specific content of step seven, trial production and preliminary testing, is as follows: based on the design parameters of the preferred scheme, produce improved tire samples; conduct preliminary tests on the trial tires in a laboratory or testing site, including static loading tests and dynamic driving tests, and record test data and phenomena.

[0034] Static loading tests assess the deformation of the tire sidewall under static pressure; dynamic driving tests assess the tire's stability and deformation during driving. Experimental results show that the engineering tires improved through Case 3 exhibit significant improvements, resolving the "twisting" phenomenon. Figure 8 As shown.

[0035] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

Claims

1. A method of improving abnormal deformation of the sidewall of a bias tire, characterized by, The method comprises the following steps of: Step one: improvement target and tire specification determination Determine the specific target of improving the abnormal deformation of the tire side of bias tire and select the tire specification (engineering tire 23.5-25) to be improved; Step two: reference design scheme determination and failure phenomenon reproduction Select a reference design scheme and reproduce the failure phenomenon of abnormal deformation of the tire side through simulation; Step three: design of the height adjustment scheme of the bead filler Set the adjustment range of the height of the bead filler according to the tire specification and the use condition and design the adjustment scheme; Step four: optimization of the angle and arrangement density of the carcass cord Adjust the angle and arrangement density of the carcass cord on the basis of the reference scheme to improve the stiffness of the tire side; Step five: design of the fiber cord layer scheme Design a single-layer fiber cord layer and determine the laying mode, position and angle thereof; Step six: simulation analysis and scheme comparison and selection Establish a simulation model, perform simulation analysis on the multiple improvement schemes designed and compare and select the optimal scheme; Step seven: trial production and preliminary test Perform trial production on the simulation-optimized improvement scheme and perform preliminary test verification; Step eight: whole vehicle test Install the trial-produced tire on an actual vehicle to perform whole vehicle test, and then observe whether the tire side of the improved tire has the wrinkle phenomenon under the same use condition.

2. A method of improving abnormal deformation of the sidewall of a bias tire as set forth in claim 1, wherein: The range of the height H1-H1' of the bead filler on the outer side of the tire in step one is 60-85 mm; the range of the height H2-H2' of the bead filler on the inner side of the tire is 50-75 mm; the fiber cord layer is a single-layer cord with an angle range of 25-35°; the laying directions of the fiber cord layer on the left and right sides thereof are " / " and "\", respectively; the angle range of the carcass cord layer is 25-35°, and the arrangement interval of the centers of the two cords of the carcass cord layer is not less than 1.25 mm.

3. A method of improving abnormal deformation of the sidewall of a bias tire as set forth in claim 1, wherein: In the reference scheme in step two, the design parameters of the reference scheme are taken as the reference, and then the tire inner / outer side bead filler height is 100% / 100%, the carcass cord angle is 100%, and the arrangement density of the carcass cord is 100%.

4. The method of claim 1, wherein: The specific steps for reproducing the failure phenomenon through simulation in step two are as follows: Establish a high-precision tire simulation model: according to the actual specification (23.5-25 engineering tire) of the tire, construct a three-dimensional geometric model in the CAE software, including the carcass cord layer, the bead filler, the bead and the fiber cord layer; input the material parameters of each component, define the hardness, density and adhesion strength of the bead filler and the cord layer; use fine mesh in the tire side area, and use shell elements or beam elements to simulate the composite behavior of fibers and metals in the cord layer and the bead; Set boundary conditions and working condition parameters: define the friction coefficient and contact stiffness of the tire and the ground, simulate the lateral force during turning; constrain the axial and radial displacement of the bead to simulate the actual installation state; set the tire inflation pressure (300 kPa), apply a single tire vertical load (9500 kg), and simulate the torsional deformation when turning 5° on the spot; Simulate the sidewall deformation mechanism: simulate the shear and bending deformation of the sidewall during cornering by rotating the rim or applying torque, focusing on the stress distribution in the lower sidewall area (where the apex rubber meets the cord ply); use co-node or embedded element technology to simulate the slip and delamination behavior of the cords and rubber, and observe the contribution of cord angle and packing density to sidewall stiffness; Reproduce and verify the failure symptoms: extract the maximum principal strain cloud map of the sidewall, identify the starting position and propagation path of the "twisted doughnut" deformation, and compare the deformation mode of the reference scheme (Case 0) with that of the actual failed tire to verify the accuracy of the simulation.

5. The method of claim 1, wherein: The specific content of the apex rubber height adjustment scheme in step three is: based on the tire specifications and service conditions, set the outer apex rubber height H1-H1' in the range of 60-85mm, and the inner apex rubber height H2-H2' in the range of 50-75mm; design adjustment schemes with different height combinations, including gradually increasing the inner and outer apex rubber height.

6. The method of claim 1, wherein: The specific content of the carcass cord angle and packing density optimization in step four is: based on the carcass cord angle of the reference scheme, design an angle adjustment scheme: gradually increase from 100% to 106%; based on the angle adjustment results, optimize the packing density of the carcass cord: increase from 100% to 109%.

7. A method of improving abnormal deformation of the sidewall of a bias tire as set forth in claim 1, wherein: The specific content of the fiber cord ply scheme design in step five is: use single-layer fiber cord ply design, left and right sides are laid in " / " and "\" manner; fiber cord ply needs to cover the steel wire ring, the angle range is set to 25-35°, the best laying angle is determined through simulation analysis to maximize the improvement of sidewall stiffness.

8. The method of claim 1, wherein: The specific content of the simulation analysis and scheme comparison in step six is: based on the finite element analysis method, establish a tire simulation model containing the adjusted apex rubber height, carcass cord angle and packing density, and fiber cord ply parameters, to ensure that the model accurately reflects the mechanical properties of the actual tire; simulate the same service conditions for the three improvement schemes, compare the carcass cord deformation, sidewall stiffness, and stress distribution of each scheme; according to the simulation analysis results, select the most significant improvement scheme as the preferred scheme.

9. The method of claim 1, wherein: The specific content of the trial production and preliminary test in step seven is: according to the design parameters of the preferred scheme, produce the improved tire sample; conduct preliminary tests on the trial tire in the laboratory or test site, including static loading test and dynamic driving test, record the test data and phenomena.

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