A method of designing a tire to reduce the force on a wrapped belt

Abstract

The application discloses a kind of reducing the force of winding belt tire design method, the tire includes belt, belt cord, crown, and tire body profile, the design method specific steps include: first by tension strain parameter setting zero degree belt cord parameter;Establish the design model of tire cross section and set up plane coordinate system, calculate the radial swing angle of zero degree belt laying;According to the fixed mold contour of tire, determine three auxiliary points, and form several auxiliary graphics according to auxiliary point, design auxiliary graphic area ratio determination obtains optimal tire body profile tendency and flat coefficient;According to the angle between the laying direction of each layer belt and the longitudinal center line of tire, determine the belt laying angle range, obtain the tire after zero degree belt force optimization.The application optimizes high tension cord, optimizes the design of tire body profile, the radial swing angle of zero degree belt, the angle between the laying direction of belt and the longitudinal center line of tire, reduces the stress of zero degree belt cord, thereby reducing the failure risk of zero degree belt cord broken wire, improves tire service life.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and in particular to a tire design method for reducing the stress on the winding belt layer. Background Technology

[0002] Low-profile, wide-base tires are increasingly used in the market. Compared with traditional dual tires, low-profile, wide-base tires have advantages such as better economy, more stable vehicle driving, larger container capacity, and higher installation and maintenance efficiency, making them popular among users. At the same time, the market's requirements for their wear resistance, durability, safety, and other performance aspects are becoming more and more stringent.

[0003] Currently, most low-profile, wide-base tires on the market utilize a wound belt structure. Although the winding methods differ, the goal is essentially the same: to control the radial growth deformation of the tire crown during inflation and use, improving the tire's resistance to uneven wear and durability, thereby extending tire lifespan. However, these wound belt structures bear significant tension in the process of controlling the radial growth deformation of the tire crown.

[0004] According to research on the fatigue performance of tire steel cord by tire steel cord manufacturers, the fatigue performance of the cord will significantly decrease when the tension exceeds 10% of its minimum breaking force. FEA simulation analysis shows that the maximum tension on the winding layer cords of current winding structures can reach 30% to 62.4% of the minimum breaking force. Furthermore, after indoor machine tool testing and dissection of tires at different usage periods, it was found that when the maximum stress reaches 30% or more of the minimum breaking force, the belt layer cords of the winding structure exhibit a failure mode of wire breakage. This wire breakage failure mode directly affects the service life of the tire.

[0005] The shortcomings of existing technology are that the maximum stress of the current wound cord can reach 26.3% to 62.4% of its minimum breaking force. After indoor machine tool testing and in actual use at different periods, in the corresponding theoretical stress range of 30% to 62.4% of the minimum breaking force of the cord, cord breakage will occur, affecting the final service life of the tire. At the same time, the conventional strength and high elongation cords used in the current wound belt layer have low pre-extension and high tensile modulus, resulting in low breaking force, weak tensile buffering capacity, and limited tensile strength. Once the tension is too high, there is a risk of breakage failure. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology, reduce the tensile stress on the winding belt layer, and reduce the risk of the winding belt layer failing due to broken threads in the tire by designing a tire design method to reduce the stress on the winding belt layer, so as to solve the problems mentioned in the background technology.

[0007] A tire design method for reducing stress on the winding belt layer, the tire comprising a belt layer, belt layer cords, a crown, and a tire carcass profile, the specific steps of the design method including:

[0008] First, the parameters of the zero-degree belt layer cord are set by the tensile strain parameter;

[0009] A design model of the tire cross section was established and a plane coordinate system was set up. The radial sway angle of the zero-degree belt layer was calculated.

[0010] Based on the outer contour of the mold for fixing the tire, three auxiliary points are determined, and several auxiliary graphics are formed based on the auxiliary points. The area ratio of the auxiliary graphics is designed, and the optimal tire body contour trend and aspect ratio are determined.

[0011] Based on the angle between the laying direction of each belt layer and the longitudinal centerline of the tire, the laying angle range of different belt layers is determined, and the tire with zero-degree belt layer stress optimization is obtained.

[0012] As a further aspect of the present invention: the specific method for setting the parameters of the zero-degree belt layer cord using the tensile strain parameter is as follows:

[0013] The strain along the direction of the zero-degree belt layer cord under tensile load is taken as the initial tensile strain ε, where ε max ∈[2.0%~3.5%];

[0014] The tensile modulus E is obtained by dividing the stress on the zero-degree belt layer cord during the stretching stage by its strain.

[0015] The test load at which the zero-degree belt layer cord breaks is taken as its corresponding tensile breaking force σ, where σ∈[1500,2000], unit: N.

[0016] As a further aspect of the present invention: the specific steps for establishing a design model of the tire cross-section and setting up a planar coordinate system to calculate the radial sway angle of the zero-degree belt layer include:

[0017] Set up a design model for the tire cross section and set up a planar coordinate system on the tire cross section, where the origin O is the intersection of the center line of the first belt layer and the axis of symmetry of the tire cross section, the horizontal coordinate is the horizontal direction along the tire cross section, and the vertical coordinate is the radial direction of the tire.

[0018] Based on the trend of the zero-degree belt layer at the tire shoulder, obtain the position coordinates P(X) of two points. P Y P ), T(X T Y T );

[0019] Then, based on the x and y coordinates of points P and T, the radial swing angle β is determined. The radial swing angle is the angle between the straight line OT and the X-axis, where β = [-3° to 2°].

[0020] As a further aspect of the present invention: the specific steps of determining three auxiliary points based on the outer contour of the mold for fixing the tire, forming several auxiliary graphics based on the auxiliary points, designing the area ratio of the auxiliary graphics, and determining the optimal tire body contour trend and aspect ratio include:

[0021] Using three auxiliary points A, B, and C on the outer contour of the mold fixed by the tire, design auxiliary lines are drawn based on the three auxiliary points to obtain several auxiliary shapes. The several auxiliary shapes include triangles, sectors, and arcs, wherein the area of ​​the auxiliary shape △ABC is fixed.

[0022] Meanwhile, line segments AB, BC, and CA intersect the existing tire carcass centerline at points D, E, G, and H, respectively.

[0023] Based on the positions of points D, E, G, and H, as well as the tire arc and auxiliary lines, several auxiliary figures and their areas are obtained.

[0024] By designing the area ratio of several auxiliary graphics, the maximum stress on the zero-degree belt layer is reduced.

[0025] As a further aspect of the present invention: the specific steps for determining the laying angle range of different belt layers based on the angle between the laying direction of each belt layer and the longitudinal centerline of the tire include:

[0026] As the angle between the laying direction of each belt layer and the longitudinal centerline of the tire decreases, the stress on the zero-degree belt layer decreases, resulting in an angle range of (22°~30°) for the first belt layer and (12°~22°) for the second, third, and fourth belt layers.

[0027] Compared with the prior art, the present invention has the following technical advantages:

[0028] The above technical solution involves setting the initial tensile strain ε and tensile breaking strength σ ranges for the cords; optimizing the radial sway angle β range of the entire layer after laying the winding belt layer; setting auxiliary points and lines to coordinate with the tire carcass contour balance design of the auxiliary graphic area ratio; and setting the angle ranges for the first, second, third, and fourth belt layers (excluding the zero-degree belt layer). This reduces the stress on the winding belt layer, thereby reducing the risk of belt layer failure due to broken cords in the tire and improving tire lifespan. Attached Figure Description

[0029] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram illustrating the steps of a tire design method according to an embodiment of this application;

[0031] Figure 2 This is a schematic diagram of the load-strain curves of an embodiment disclosed in this application;

[0032] Figure 3 Schematic diagrams of load-strain curves for several embodiments and comparative examples disclosed in this application;

[0033] Figure 4 This is a planar coordinate system diagram of an embodiment disclosed in this application;

[0034] Figure 5 This is a schematic diagram showing how the Y-coordinate positions of P and T in different embodiments disclosed in this application change within the first and fourth quadrants of the planar coordinate system.

[0035] Figure 6 This is a schematic diagram of the fetal carcass outline of an embodiment disclosed in this application;

[0036] Figure 7 This is a schematic diagram of the auxiliary graphic formed by the outline of the tire body and auxiliary lines of an embodiment disclosed in this application;

[0037] Figure 8 This is a schematic diagram of the belt layer laying direction in an embodiment disclosed in this application. Detailed Implementation

[0038] 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 a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Please refer to Figure 1 In this embodiment of the invention, a tire design method for reducing the stress on the winding belt layer is provided. The tire includes a belt layer, belt layer cords, a crown, and a tire carcass profile. The design method specifically includes the following steps:

[0040] S1. First, set the parameters of the zero-degree belt layer cord by using the tensile strain parameter;

[0041] In this embodiment, the winding belt layer cord used is replaced by a new high-strength, high-elongation (HE NT) cord instead of a conventional high-strength, high-elongation (HE HT) cord. The high-elongation performance of the new cord is no less than that of the existing cord, and it also has a higher breaking strength.

[0042] Its high elongation performance is represented by the initial tensile strain ε, the modulus of the tensile + elongation section is represented by E, E = tensile stress / tensile strain; the corresponding tensile breaking force is represented by σ.

[0043] The basic concept of ε: the strain along the direction of the cord when the cord is subjected to a tensile load;

[0044] The concept of tensile modulus E: the stress on the cord during the tensile stage divided by its strain;

[0045] σ represents the test load at which the cord breaks, and the unit is N;

[0046] The specific method is as follows:

[0047] The strain along the direction of the zero-degree belt layer cord under tensile load is taken as the initial tensile strain ε, where ε max ∈[2.0%~3.5%];

[0048] The tensile modulus E is obtained by dividing the stress on the zero-degree belt layer cord during the stretching stage by its strain.

[0049] The test load at which the zero-degree belt layer cord breaks is taken as its corresponding tensile breaking force σ, where σ∈[1500,2000], unit: N.

[0050] like Figure 2 and Figure 3 As shown in the figure, the results of the tensile test on the cord are as follows: Figure 2 This is a schematic diagram of the load-strain curve. Figure 3 Schematic diagrams of load-strain curves for multiple embodiments and comparative examples;

[0051] Table 1. Tensile Test Results Data

[0052]

[0053] According to the table above, the protection range of ε is: under the same conditions, the greater the initial tensile strain and the greater the stress on the cord, the greater the ε protection range. max ∈[2.0%~3.5%]; Under the same ε conditions, as the tensile breaking strength increases, the percentage of stress on the cord decreases, and the required tensile breaking force range σ∈[1500, 2000], unit: N.

[0054] S2. Establish a design model of the tire cross-section and set up a plane coordinate system to calculate the radial sway angle of the zero-degree belt layer. The specific steps include:

[0055] Three auxiliary points A, B, and C are determined based on the outer contour of the mold with the tire fixed. Design auxiliary lines are then drawn based on these three points to obtain several auxiliary shapes, including triangles, sectors, and arcs. The area of ​​auxiliary shape △ABC is fixed. In this embodiment, a triangle is used for specific illustration, resulting in △ABC with an area S. ABC For fixed purposes;

[0056] Meanwhile, line segments AB, BC, and CA intersect the existing tire carcass centerline at points D, E, G, and H, respectively.

[0057] Based on the positions of points D, E, G, and H, as well as the tire arc and auxiliary lines, several auxiliary figures (including: sector and arc) are obtained. The areas of the auxiliary figures are represented by S1, S2, S3, and S4, respectively.

[0058] By designing the area ratio of auxiliary graphics S1, S2, S3, S4 to the area of ​​△ABC, the maximum tension on the zero-degree belt layer is reduced.

[0059] In this embodiment, as Figure 4 and Figure 5 As shown, where Figure 4 This is a diagram in a plane coordinate system. Figure 5 This diagram illustrates how the Y-coordinate positions of P and T vary within the first and fourth quadrants of a planar coordinate system in different embodiments.

[0060] Divided by the longitudinal centerline of the tire, the left and right belt layers of the profile are symmetrical, and the design model is the right side of a cross-section of the tire;

[0061] A planar coordinate system (X, Y) is set on the cross section, where the origin O (0, 0) is the intersection of the center line of the first belt layer and the axis of symmetry of the tire cross section, the X-axis is the horizontal transverse direction along the tire cross section, and the Y-axis is the radial direction of the tire.

[0062] Design P(X) P Y P ), T(X T Y T The position of points P and T, the line connecting points P and T controls the trend of the shoulder wrapping layer and the belt layer, the position of P and T;

[0063] There is a certain proportional relationship between the X coordinates of P and T and half of the tread width (HW) (HW / 2);

[0064] That is (2X) T ) / HW = [0.78~0.85], X P =X T -W0B,(W0B*2) / HW=(0.39~0.46),

[0065] Where W0B represents the horizontal width at 0°B, and HW represents the horizontal width of the outer contour of the mold crown;

[0066] The design of the ordinates of points P and T is controlled by the radial sway angle, that is, by the angle β between the straight line OT and the X-axis (referred to as the radial sway angle). T =X T sinβ, where β=[-3°~2°];

[0067] In different embodiments, the Y-coordinate positions of P and T will vary in the first and fourth quadrants of the planar coordinate system.

[0068] The maximum force on the wound belt layer under standard air pressure and load in the simulation analysis is represented by Strain.

[0069] Table 2. Radial Swing Angle Data in Different Embodiments

[0070]

[0071] According to the table above, in the first quadrant: the larger β is, the smaller the force on the 0° belt layer (0°B); in the fourth quadrant: the larger β is, the greater the force on the 0° belt layer (0°B); the value of β ranges from -3° to 2°.

[0072] S3. Based on the outer contour of the mold for fixing the tire, determine three auxiliary points, and form several auxiliary shapes (including triangles, fan shapes, and bow shapes) based on the auxiliary points. Design the area ratio of the auxiliary shapes to determine the optimal tire body contour trend and aspect ratio.

[0073] In this embodiment, as Figure 6 and Figure 7 As shown, Figure 6 This is a schematic diagram of the fetal body outline. Figure 7 A schematic diagram of the triangle formed by the outline of the fetal body and auxiliary lines;

[0074] Table 3. Area Ratio of Different Auxiliary Graphics and Stress Data of Zero-Degree Belt Layer

[0075]

[0076] On the comparative example design model, three fixed points A, B, and C are determined, and three design auxiliary lines are drawn to form a triangular unit. The area of ​​△ABC is fixed.

[0077] Point A is the intersection of the axis of symmetry of the tire cross section and the horizontal axis of the widest position of the tire cross section (referred to as the horizontal axis of the cross section), point B is the shoulder point of the outer contour of the crown of the cross section, and point C is the heel point.

[0078] Line segments AB, BC, and CA intersect the centerline of the tire body in Comparative Example 3 at points D, E, G, and H, respectively. The embodiment designs the positions of points D, E, F, and G, and the area S enclosed by arcs O'D, DE, EG, and GH, and auxiliary lines AB, BC, and CA. ADO’ S BDE S EFG S CGH This is to achieve a balanced design of the tire body contour and reduce the maximum stress on the 0-degree belt layer.

[0079] Point O' is a distance offset from point O along the radial direction of the tire into the tire by (first belt layer thickness / 2) + (carcass thickness / 2).

[0080] Point D lies on line segment AB;

[0081] Points E and G are on line segment BC;

[0082] Point F is the intersection of the tire carcass centerline at the widest position on the design model and the horizontal axis at the widest position of the tire cross-section.

[0083] Point H is on line segment AC;

[0084] Tire height – vertical distance from point O' to point C;

[0085] Tire body width — length of line segment AF.

[0086] The areas of the auxiliary shapes enclosed by the design elements and auxiliary lines of the tire body outline are represented by the codes S1, S2, S3, and S4, respectively, representing S. ADO’ S BDE S EFG S CGH ;

[0087] According to Table 3, we can obtain:

[0088] When S2 decreases, the force on 0°B decreases, (S2 / S ABC )*100%∈(4.0~8.0%);

[0089] When S3 decreases, the force on 0°B decreases, (S3 / S ABC )*100%∈(6.0~9.0%);

[0090] When S4 decreases, the force on 0°B decreases, (S4 / S ABC )*100%∈(3.0~5.0%);

[0091] Tire aspect ratio: Tire height-to-width ratio ∈ (90.0%~93.0%).

[0092] S4. Based on the angle between the laying direction of each belt layer and the longitudinal centerline of the tire, determine the laying angle range of different belt layers to obtain the tire with optimized stress of the zero-degree belt layer. The specific steps include:

[0093] As the angle between the laying direction of each belt layer and the longitudinal centerline of the tire decreases, the stress on the zero-degree belt layer decreases, resulting in an angle range of (22°~30°) for the first belt layer and (12°~22°) for the second, third, and fourth belt layers.

[0094] In this embodiment, as Figure 8 As shown in the diagram, the belt layer laying direction is a schematic diagram. The belt layer angle in the diagram is the angle between the laying direction and the longitudinal centerline of the tire. The belt layer direction is: one left-falling direction is positive, and one right-falling direction is negative.

[0095] Table 4. Stress data of belt layers at different laying angles and at zero degrees.

[0096]

[0097] According to Table 4, as the beam angle decreases, the force on the zero-degree beam layer (0°B) decreases; the angle range of the first beam layer is (22°~30°), and the angle range of the second, third, and fourth beam layers is (12°~22°).

[0098] Except for the zero-degree belt layer (0°B), the zero-degree belt layer (0°B) experiences less stress when the other belt layers are laid in a cross pattern compared to when they are laid in the same direction.

[0099] By combining the above design methods to optimize the tire, the percentage of the maximum force on σ of the zero-degree belt layer (0°B) was reduced from 62.4% to 29.7%, showing a significant improvement.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents, all of which should be included within the scope of protection of the invention.

Claims

1. A tire design method for reducing stress on the winding belt layer, the tire comprising a belt layer, belt layer cords, a crown, and a tire carcass profile, characterized in that, The specific steps of the design method include: First, the parameters of the zero-degree belt layer cord are set by the tensile strain parameter; A design model of the tire cross section was established and a plane coordinate system was set up. The radial sway angle of the zero-degree belt layer was calculated. Based on the outer contour of the fixed mold for the tire, three auxiliary points are determined, and several auxiliary shapes are formed according to these points. The area ratio of the auxiliary shapes is designed to determine the optimal tire body contour and aspect ratio. The specific steps include: Using three auxiliary points A, B, and C on the outer contour of the mold with the tire fixed, design auxiliary lines are drawn based on these three auxiliary points to obtain several auxiliary shapes, including triangles, sectors, and arcs. The three auxiliary points include: point A, the intersection of the axis of symmetry of the tire cross-section and the horizontal axis at the widest point of the tire cross-section; point B, the shoulder point of the outer contour of the crown of the cross-section; and point C, the heel point. A triangle △ABC is formed with A, B, and C as vertices, and the area of ​​triangle △ABC is fixed. Meanwhile, line segments AB, BC, and CA intersect the existing tire carcass centerline at points D, E, G, and H, respectively. Based on the positions of points D, E, G, and H, as well as the tire arc and auxiliary lines, several auxiliary figures and their areas are obtained. By designing the area ratio of several auxiliary graphics, the maximum stress on the zero-degree belt layer is reduced; Based on the angle between the laying direction of each belt layer and the longitudinal centerline of the tire, the laying angle range of different belt layers is determined, and the tire with zero-degree belt layer stress optimization is obtained.

2. The tire design method for reducing the stress on the winding belt layer according to claim 1, characterized in that, The specific method for setting the tensile strain parameter of the zero-degree belt layer cord is as follows: The strain along the direction of the zero-degree belt layer cord under tensile load is taken as the initial tensile strain. ε ,in ε max ∈[2.0%~3.5%]; The tensile modulus is obtained by dividing the stress on the zero-degree belt layer cord during the stretching stage by its strain. E ; The test load at which the zero-degree belt layer cord breaks is taken as its corresponding tensile breaking force σ, where σ∈[1500,2000], unit: N.

3. The tire design method for reducing the stress on the winding belt layer according to claim 1, characterized in that, The specific steps for establishing a design model of the tire cross-section and setting up a planar coordinate system to calculate the radial sway angle of the zero-degree belt layer include: Define a design model of the tire cross-section and establish a planar coordinate system on the tire cross-section, where the origin is... O The intersection of the centerline of the first belt layer and the axis of symmetry of the tire cross section is the point where the horizontal axis is the horizontal direction along the tire cross section and the vertical axis is the radial direction of the tire. The coordinates of two points are obtained based on the trend of the zero-degree belt layer on the tire shoulder. P(X P ，Y P ), T(X T ，Y T ) ; Then, based on the x and y coordinates of points P and T, determine the radial swing angle. β The radial swing angle is the angle between the straight line OT and the X-axis, where β = [-3°~2°].

4. The tire design method for reducing the stress on the winding belt layer according to claim 1, characterized in that, The specific steps for determining the laying angle range of different belt layers based on the angle between the laying direction of each belt layer and the longitudinal centerline of the tire include: As the angle between the laying direction of each belt layer and the longitudinal centerline of the tire decreases, the stress on the zero-degree belt layer decreases, resulting in an angle range of 22°~30° for the first belt layer and 12°~22° for the second, third, and fourth belt layers.

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