A tire design method to eliminate cap ply folding

Abstract

The present invention discloses a tire design method for eliminating cap ply folding. The method comprises obtaining the cross-sectional material distribution structure of a finished tire and determining the required amount of rubber at each location of the tire to obtain the finished tire's tread plus wing rubber thickness AB, the sidewall rubber plus cushion rubber thickness BC, and the cap ply end rubber thickness AC; converting the obtained finished tire thickness dimensions into semi-finished material dimensions that satisfy a preset dimensional relationship; and designing and manufacturing a tire with no cap ply folding based on the obtained semi-finished tire dimensional relationship and the direction of rubber flow at the tread shoulder during the vulcanization process. Through precise calculations during the design phase and assessment of material deformation during the manufacturing process, the present invention eliminates tire cap ply folding that occurs during the manufacturing process, improving tire performance, shortening the development cycle, increasing efficiency, and reducing development costs.

Description

Technical Field

[0001] The invention relates to the technical field of tire design, in particular to a tire design method for eliminating cap ply folding. Background Art

[0002] The cap ply is one of the main reinforcement components of a tire. Its primary function is to restrain the tire's crown skeleton material, reduce crown deformation during operation, and enhance the tire's high-speed performance. During the passenger car tire design process, to meet requirements such as ground contact, high-speed performance, and comfort, the cap ply is typically wrapped around the belt ply, using one or two layers for full coverage, or a one-layer crown and two-layer shoulder structure.

[0003] The cap ply structure is laminated to the belt layer through a process of calendering, cutting, and winding, and then the tread rubber is laminated to the outside. The cap ply's final shape is determined after the tire is vulcanized. Many factors can influence the cap ply's shape during the design and manufacturing process, which in turn affects the tire's conformity to cross-section requirements and its performance.

[0004] The main problems in the use of the cap layer occur in the shoulder of the tire, in the form of folds of varying degrees; the shoulder position is the area where tire stress and strain are concentrated. The problems that occur have a great impact on tire performance, which will lead to a reduction in the tire's high speed or durability performance.

[0005] The shortcomings of the existing technology are that, in order to deal with the phenomenon of cap layer folding, the tire cross section is generally used to detect whether the cap layer folding occurs after the tire sample is produced. If the cap layer folding occurs, the target value of the cap layer width, or the single-turn winding width, or the winding tension is tried to be changed. The defects of the technology are: First, after the folding problem occurs, a solution is found. After the sample is trial-produced, the tire cross section is cut to confirm whether the cap layer folding occurs; when the cap layer folding is found, the above-mentioned solution is adopted to re-produce the sample tire and confirm the cap layer condition of the finished tire; generally, after multiple trials and confirmations, the cap layer folding condition is improved; however, the result can only reduce the degree of folding, and cannot eliminate the cap layer folding phenomenon. Second, either the design goal of the cap layer is changed, or the manufacturing complexity is increased. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology. To achieve the above purpose, a tire design method that eliminates the folding of the cap ply is adopted to solve the problems raised in the above background technology.

[0007] A tire design method for eliminating cap ply folding, comprising the following steps:

[0008] Step S1, obtaining the cross-sectional material distribution structure of the finished tire, and confirming the rubber material demand at each position of the tire, to obtain the tread and wing rubber thickness AB, the sidewall rubber or independent cushion rubber thickness BC, and the cap ply end rubber thickness AC of the finished tire;

[0009] Step S2: Convert the thickness of the finished tire to the size of the semi-finished material, and satisfy the following dimensional relationship:

[0010] a / m>AB;

[0011] b / m>BC;

[0012] a / m-AB

[0013] Wherein, a is the thickness of the cap and wing rubber of the semi-finished tire, b is the thickness of the sidewall rubber of the semi-finished tire, and m is the elongation coefficient of the conversion between the semi-finished tire and the finished tire;

[0014] Step S3: designing and manufacturing a tire with no folds in the cap ply according to the obtained size relationship of the semi-finished tire and the flow direction of the rubber material at the tread shoulder during the vulcanization process.

[0015] As a further solution of the present invention: the cross-section material distribution structure includes a tread shoulder, a sidewall rubber, a belt layer, and a cap layer.

[0016] As a further solution of the present invention, the sum of the thickness of the tread plus the wing rubber AB and the thickness of the sidewall rubber or the independent cushion rubber BC of the finished tire is equal to the thickness of the cap ply end rubber AC.

[0017] As a further solution of the present invention, the specific steps of identifying the flow direction of the rubber material at the tread shoulder during the vulcanization process include:

[0018] An identification film is set vertically in the semi-finished tire component. During the vulcanization process, the flow direction of the tread shoulder rubber material is determined according to the position and direction of the identification film.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] By utilizing the aforementioned technical solution, the direct influencing factors of cap ply folding are eliminated during the design phase by exploiting the causes of cap ply folding. The dimensions of the tread shoulder, sidewall rubber, belt, and cap ply are then designed to achieve a tire that meets the pre-set dimensional relationships. This reduces the number of prototype trials required for product development, thereby improving trial production efficiency, lowering development costs, improving tire performance, and shortening the development cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings:

[0022] ​Figure 1 A schematic diagram of the steps of the tire design method according to the embodiment disclosed in this application;

[0023] Figure 2 A schematic diagram of external force acting during the green tire pressing process in the prior art;

[0024] Figure 3 A schematic diagram of the flow direction of the rubber material during the vulcanization process of the embodiment disclosed in this application;

[0025] Figure 4 A schematic diagram of the dimensions of a semi-finished tire according to an embodiment disclosed in this application;

[0026] Figure 5 A schematic diagram of the position of the marking film according to the embodiment disclosed in this application;

[0027] Figure 6 This is a schematic diagram of the shape of the marking film when the rubber material on the tread shoulder does not flow according to the embodiment disclosed in this application;

[0028] Figure 7 This is a schematic diagram of the shape of the marking film when the rubber material flows from the tread shoulder to the sidewall of the embodiment disclosed in this application. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] In this embodiment, the cap ply buckling phenomenon is first analyzed and evaluated, wherein the cap ply buckling region is located at the tire shoulder;

[0031] Tire cap layer discount principle description:

[0032] a. Tire forming process: The effect after the cap layer is wound on the belt drum is shown in the figure below. The material is attached to the belt layer and the edge is attached to the belt drum. Since there is no external force that causes the cap layer to warp during the lamination process, the edge of the cap layer will not warp during this process.

[0033] b. Tread lamination and tire green pressing process:

[0034] When applying the tread, center the tread over the cap ply. The cap ply is pressed downward during this process, preventing any buckling. The red line corresponds to the cap ply material.

[0035] c. Green tire pressing process:

[0036] like Figure 2 As shown, the figure is a schematic diagram of the external force acting during the tire pressing process in the prior art; because the tire surface has no boundary restrictions, and the external force applied to the tire is pressed from the crown → sidewall → rim direction, that is, T0 → T1 → T2 → T3 → T4 → T5, the direction of the force points to the tire, and the whole process will not cause the cap layer to be folded.

[0037] d. Tire vulcanization stage:

[0038] The green tire stretches during contact with the mold, with the crown and shoulders stretching differently. Furthermore, there's a time lag between the green tire surface and the mold, creating a pressure differential between the areas that have and haven't touched the mold. This can cause undesirable flow of the upper sidewall or wing rubber around the green tire's shoulders. Rubber that wasn't originally beneath the cap ply on the green tire is squeezed between the bladder and the inner surface of the mold, causing it to flow abnormally below the end of the cap ply, causing it to buckle.

[0039] Please refer to Figure 1 In an embodiment of the present invention, a tire design method for eliminating cap ply folding includes the following steps:

[0040] Step S1, obtaining a cross-sectional material distribution structure of a finished tire and confirming the rubber material demand at each position of the tire to obtain the tread and wing rubber thickness AB, the sidewall rubber or independent cushion rubber thickness BC, and the cap ply end rubber thickness AC of the finished tire, wherein the cross-sectional material distribution structure includes the tread shoulder, sidewall rubber, belt layer, and cap ply;

[0041] In this embodiment, Figure 3 As shown, the figure is a schematic diagram of the flow direction of the rubber material on the tread shoulder during the vulcanization process;

[0042] In a finished tire, the rubber material thickness at the end of the cap ply is AC, wherein the thickness of the tread and wing rubber is AB, and the thickness of the sidewall rubber or independent cushion rubber is BC. In this embodiment, the sum of the thickness of the tread and wing rubber AB and the thickness of the sidewall rubber or independent cushion rubber BC of the finished tire is equal to the rubber material thickness AC at the end of the cap ply, that is, the line length AB + BC = AC;

[0043] Step S2: Convert the thickness of the finished tire to the size of the semi-finished material, and satisfy the following dimensional relationship:

[0044] a / m>AB;

[0045] b / m>BC;

[0046] a / m-AB

[0047] Wherein, a is the thickness of the cap and wing rubber of the semi-finished tire, b is the thickness of the sidewall rubber of the semi-finished tire, and m is the elongation coefficient of the conversion between the semi-finished tire and the finished tire;​

[0048] In this embodiment, Figure 4 As shown, the figure is a schematic diagram of the dimensions of a semi-finished tire;

[0049] For semi-finished rubber, the thickness of the cap and wing rubber is a, and the thickness of the sidewall rubber is b;

[0050] Step S3: designing and manufacturing a tire with no folds in the cap ply according to the obtained size relationship of the semi-finished tire and the flow direction of the rubber material at the tread shoulder during the vulcanization process.

[0051] In this embodiment, according to the design of the above-mentioned dimensional relationship, while simultaneously meeting the requirements of the three dimensional formulas, the design and production are based on the flow direction of the rubber material on the tread shoulder during the vulcanization process, thereby obtaining a tire with no folds in the cap layer that meets the tire design size and performance target requirements.

[0052] In this embodiment, the specific steps of identifying the flow direction of the rubber material on the tread shoulder during the vulcanization process include:

[0053] An identification film is set vertically in the semi-finished tire component. During the vulcanization process, the flow direction of the tread shoulder rubber material is determined according to the position and direction of the identification film.

[0054] In this embodiment, the specific steps for identifying the flow direction of the rubber material are as follows:

[0055] First, an identification film with a color different from the component material is vertically embedded in the semi-finished component. During vulcanization, the color-differentiated glue will shift according to the flow direction of the rubber, and the flow direction of the rubber can be determined based on the displacement direction.

[0056] like Figure 5 As shown in the figure, it is a schematic diagram of the position of the identification film, and the film or rubber strip (the color is different from the tread or sidewall rubber) is vertically inserted into the tread or sidewall of the semi-finished tire;

[0057] Determine the direction of rubber flow:

[0058] If the adhesive does not flow, insert the marking film, such as Figure 6 As shown, the figure is a schematic diagram of the position and shape of the marking film when the rubber material does not flow.

[0059] If the rubber flows:

[0060] When flowing from the shoulder to the sidewall, the inserted identification film, such as Figure 7 As shown, the position and shape of the marking film when the rubber material flows;

[0061] When the rubber flows from the tire side to the tire shoulder, the deflection direction of the inserted marking film is the same as Figure 7 on the contrary.

[0062] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents, and all should be included within the scope of protection of the present invention.

Claims

1. A tire design method for eliminating cap ply folding, characterized in that: The specific steps include: Step S1, obtaining the cross-sectional material distribution structure of the finished tire, and confirming the rubber material demand at each position of the tire, to obtain the tread and wing rubber thickness AB, the sidewall rubber or independent cushion rubber thickness BC, and the cap ply end rubber thickness AC of the finished tire; Step S2: Convert the thickness of the finished tire to the size of the semi-finished material, and satisfy the following dimensional relationship: a / m>AB; b / m>BC; a / m-AB, where a is the thickness of the cap and wing rubber of the semi-finished tire, b is the thickness of the sidewall rubber of the semi-finished tire, and m is the elongation coefficient of the conversion between the semi-finished tire and the finished tire; Step S3: designing and manufacturing a tire with no folds in the cap ply according to the obtained size relationship of the semi-finished tire and the flow direction of the rubber material at the tread shoulder during the vulcanization process. The cross-section material distribution structure includes a tread shoulder, a sidewall rubber, a belt layer, and a cap layer.

2. A tire design method for eliminating cap ply folding according to claim 1, characterized in that: The sum of the tread plus wing rubber thickness AB and the sidewall rubber or independent cushion rubber thickness BC of the finished tire is equal to the cap layer end rubber thickness AC.

3. A tire design method for eliminating cap ply folding according to claim 1, characterized in that: The specific steps of identifying the flow direction of the tread shoulder rubber material during the vulcanization process include:

4. A tire design method for eliminating cap ply folding according to claim 1, characterized in that: An identification film is set vertically in the semi-finished tire component. During the vulcanization process, the flow direction of the tread shoulder rubber material is determined according to the position and direction of the identification film. ​

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