Pre-vulcanization green tire for improving riding comfort of passenger car tire

Abstract

The utility model relates to the technical field of tire design, in particular to a green tire before vulcanization, which is used for improving the riding comfort of a passenger car tire. The utility model relates to a raw tire before vulcanization for improving the riding comfort of a passenger car tire. The raw tire comprises a tread, a nylon belt ply, a steel wire belt ply, a sidewall, a tire body cord thread layer, a lining layer, apex, a steel wire ring and base rubber, according to the utility model, the cord thread residual stress caused by dry heat shrinkage of the material is counteracted by utilizing the change of the physical dimension of the material, so that the residual stress of the tire body cord thread in a vulcanized finished product is reduced. The residual stress of the tire cord is low, the vibration amplitude is reduced when the tire cord is excited after inflation loading, and the driving comfort of a vehicle can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of tire design, in particular to a green tire before vulcanization for improving the ride comfort of passenger vehicle wheels. Background Art

[0002] The rapid development of the automotive industry has put forward higher and higher requirements for tire components, and the demand for comfort, as a kind of ride experience, has gradually increased. Ride comfort is the degree to which the vibration of the vehicle chassis / tire is absorbed and then perceived by the passengers. The unevenness of the road surface serves as an excitation, and the generated vibration is transmitted to the passengers through the tire / chassis.

[0003] The tire is the only ground contact component of the vehicle and makes important contributions to the comfort of the whole vehicle in both vibration and vibration absorption. Improving the ride comfort of the vehicle can start from three aspects of the tire. 1 - Material solutions: Reducing the hardness of the tread material can effectively reduce the impact vibration. Increasing the hysteresis loss of the tread material can enhance the vibration absorption effect. 2 - Structural solutions: Reducing the rigidity of the tire sidewall can effectively reduce the vibration of the wheel and increase the vibration absorption. 3 - Tread pattern shape solutions: Reducing the stiffness of the tread can also effectively reduce the vibration of the wheel and improve the comfort.

[0004] Deficiencies of the existing solutions:

[0005] 1. Adjusting the direction of material hardness and hysteresis loss will have negative impacts on the handling performance, wear and rolling resistance of the tire;

[0006] 2. Reducing the rigidity of the tire sidewall will reduce the handling response speed of the vehicle;

[0007] 3. Reducing the stiffness of the tread will reduce the wear mileage and handling performance of the tire. Summary of the Invention

[0008] In order to solve the above technical problems, the purpose of the utility model is to provide a green tire before vulcanization for improving the ride comfort of passenger vehicle wheels. After vulcanization, the green tire can effectively improve the ride comfort while the handling performance, wear and other properties of the passenger vehicle tire are not affected.

[0009] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0010] A green tire before vulcanization for improving the ride comfort of passenger vehicle wheels, the green tire includes a tread, a nylon belt layer, a steel belt layer, a tire sidewall, a carcass ply layer, an inner liner, a chafer, a bead wire and a base rubber; the cord length Lg of the green tire before vulcanization is as follows:

[0011]

[0012] Lc is the length of the tire's finished product cord, C is the comprehensive elongation rate of the carcass cord, with a value of -1.0% to 0, α is the dry heat shrinkage rate of the carcass cord, and β is the elongation rate of the carcass cord.

[0013] Preferably, for the carcass cord, α = 1% to 3%, and more preferably, α = 1.5% to 2.5%.

[0014] Preferably, the elongation rate β of the carcass cord is -3.0% to -1.5%, and more preferably, β = -2.5% to -1.0%.

[0015] For the dry heat shrinkage property α of the carcass cord material, chemical change: The polymer material of the carcass cord forms crystals under the tensile state. During the tire vulcanization process, the cord is heated and the crystals are reorganized. Since both ends of the cord are fixed by the bead toes respectively, the cord has a tendency to shrink and thus forms internal stress.

[0016] Due to the adoption of the above technical solution in the present utility model, for the geometric elongation β of the carcass cord before and after tire vulcanization, physical change: The percentage change β of the cord length in the finished tire compared to the cord length in the green tire. β is a design parameter. β > 0 indicates that the cord is geometrically stretched; β < 0 indicates that the cord is geometrically compressed.

[0017] Through calculation, comprehensively consider the influence of the two effects of α and β on the residual stress in the finished product cord. When C = 0, there is no residual stress in the carcass cord; when C > 0, the carcass residual stress shows a tensile effect; otherwise, it is a compressive effect. Use the change in the geometric size of the material to offset the cord residual stress caused by the dry heat shrinkage of the material, thereby reducing the residual stress of the carcass cord in the finished product after vulcanization. The lower the residual stress of the tire cord, the lower the vibration amplitude when excited after inflation and loading, which can improve the ride comfort of the vehicle. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the finished tire components;

[0019] Figure 2 It is a schematic diagram of 1 / 2Lc of the carcass cord length in the finished product (after vulcanization);

[0020] Figure 3 It is a schematic diagram of the green tire components before vulcanization;

[0021] Figure 4 It is a schematic diagram of 1 / 2Lg of the carcass cord length in the green tire (before vulcanization);

[0022] Figure 5 It is a comparison schematic diagram of 1 / 2Lc and 1 / 2Lg of the carcass cord before and after tire vulcanization. Detailed Embodiment

[0023] The following will further elaborate on the present utility model in conjunction with the accompanying drawings: This embodiment is implemented on the premise of the technical solution of the present utility model, and detailed implementation manners are given, but the protection scope of the present utility model is not limited to the following embodiments.

[0024] As Figure 1 Schematic diagram of a passenger tire structure, including a tread 1, a nylon belt layer 2, a steel belt layer 3, a tire sidewall 4, a carcass ply layer 5, an inner liner 6, a chafer 7, a bead wire 8, and a base rubber 9.

[0025] As Figure 2 Shown, the length Lc of the finished tire cord. In a tire product with specific dimensions and structures, the value of Lc is a fixed value. In a tire structure with a single-layer carcass, along the center line of the carcass cord, the curved length between the left and right bead toes is intercepted to obtain the Lc value. In a tire structure with a double-layer carcass, along the middle line of the two-layer carcass cord, the curve between the left and right bead toes is also intercepted to obtain the Lc value.

[0026] Determine the value of α according to the dry heat shrinkage rate property of the carcass cord material. For common carcass cords, α = 1% - 3%. Using Equation 1 in Equation (1.1),

[0027] β + α = C (1.2)

[0028] Obtain β (Note: If the value of C is too small, it will cause the finished cord to bend or pleat. The value of C is preferably between -1.0% and 0).

[0029] Using Equation 2 in Equation (1.1) and the value of Lc

[0030]

[0031] Obtain the value range of Lg.

[0032] The length Lg of the green tire carcass cord is defined as the curved length between the left and right bead toes intercepted on the building drum of the green tire during the assembly process before vulcanization to obtain the Lg value. By adjusting the width DW of the building drum, the value of Lg is made to conform to the value range calculated in Step 3. The path of Lg is the same as that of Lc: in a tire structure with a single-layer carcass, along the center line of the carcass cord, the curved length between the left and right bead toes is intercepted; in a tire structure with a double-layer carcass, along the middle line of the two-layer carcass cord, the curve between the left and right bead toes is intercepted. As Figure 3 Shown.

[0033] Verification example:

[0034] The tire size is 225 / 60R18, the tire structure is a double carcass, the carcass cord material is 1100 dtex / 2 DSP, and the dry heat shrinkage rate α = 1.8. The test of the dry heat shrinkage rate is determined according to GB / T 19390-2014. The geometric elongation rate β of the carcass cord and the design values of the comprehensive elongation rate C of the cord are shown in Table 1.

[0035] The ride comfort of the tire is evaluated by the subjective evaluation method of the vehicle, and the impact feeling and vibration filtering of the subjective evaluation driver are used to characterize the ride comfort of the tire. The test vehicle model is Geely Vision X6, the test site is the CATARC Yancheng Test Center, the vehicle load is half load, the test air pressure is 230 kPa, and the test vehicle speed is 60 km / h.

[0036] The results are shown in Table 1:

[0037]

[0038] It can be seen from the data in Table 1 that the β value of the example changes from positive to negative compared with the reference example, and the carcass cord changes from geometric tension to geometric compression state. After superimposing the dry heat shrinkage of the cord, the comprehensive elongation rate of the cord is negative, that is, the cord of the finished product is in a compressed state, reducing the internal stress of the cord under inflation loading. The comfort scores of Examples 1 to 3 are improved to varying degrees compared with the reference example. At the same time, the three examples do not involve the adjustment of the tread material and tire structure, maintaining the performance such as the handling performance and abrasion resistance of the tire.

[0039] The above is the description of the embodiments of the present invention. Through the above description of the disclosed embodiments, those skilled in the art can implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel points disclosed herein.

Claims

1. A green tire for improving the ride comfort of a passenger car tire, the green tire comprising a tread, a nylon belt layer, a steel belt layer, a sidewall, a carcass ply layer, an inner liner, a chafer, a bead core, and a base rubber; The green tire is characterized in that, Before vulcanization, The cord length Lg of the green tire is as follows: Lc is the cord length of the finished tire, C is the comprehensive elongation rate of the carcass cord, with a value of -1.0% to 0, α is the dry heat shrinkage rate of the carcass cord, and β is the elongation rate of the carcass cord. ； 2. The green tire for improving the ride comfort of a passenger car tire according to claim 1, The green tire is characterized in that, 3. The green tire for improving the ride comfort of a passenger car tire according to claim 1, The green tire is characterized in that, α=1~3%。 4. The green tire for improving the ride comfort of a passenger car tire according to claim 1, The green tire is characterized in that, α=1.5~2.5%。 5. The green tire for improving the ride comfort of a passenger car tire according to claim 1, The green tire is characterized in that, The elongation rate β of the carcass cord is -3.0 to -1.5%.

6. The green tire for improving the ride comfort of a passenger car tire according to claim 1, The green tire is characterized in that, β=-2.5~-1.0%。

Images