Method for measuring bending amount of carcass cord of all-steel-wire radial tire

Abstract

The invention discloses a method for measuring the bending amount of a carcass cord of an all-steel radial tire, which comprises the following steps of: cutting the tire into a flat section, and establishing a global coordinate reference; removing the lining layer to obtain a complete carcass cord, connecting the mark points on the front and back surfaces to form a measurement datum line, and establishing a space coordinate system; accurately mapping the three-dimensional cord thread form into a two-dimensional plane rubbing graph, and generating a standardized measurement data source through transfer fixation; based on the plane rubbing graph, the bending amount of the tire body cord thread is obtained through geometric modeling and trigonometric function calculation, then the bending degree is calculated, and the bending degree is converted into lossless quantitative analysis and engineering parameter output of cord thread deformation. According to the method, the measurement of the bending amount and the bending degree of the tire body cord thread is realized by combining geometric modeling and trigonometric function calculation through standardized section cutting, symmetric marking, inner lining layer lossless stripping and carbon powder plane rubbing technologies, and quantitative data support is provided.

Description

Technical Field

[0001] The invention relates to the technical field of tire carcass design, in particular to a method for measuring the curvature of a carcass cord of a full-steel radial tire. Background Art

[0002] In the early stages of all-steel radial tire development, comprehensive assessments of product cross-sectional quality and performance are necessary. The curvature of the carcass cord not only directly impacts cross-sectional quality, such as carcass turnup height, but also influences performance such as high speed and durability. Therefore, understanding cord curvature during the initial stages of product development is crucial. However, if the measured cord curvature fails to accurately represent the actual curvature, it can mislead product improvement strategies and even mask product issues, leading to more serious quality issues once the product enters the market and negatively impacting brand reputation.

[0003] At present, there is no complete method in the industry for accurately measuring the bending amount and degree of the cord of a full-steel radial tire. X-ray detection is generally used to determine whether the cord is bent. Although X-ray detection technology is relatively mature, its main function is to detect the sparse wire opening and bubble problem of the product throughout the whole circumference. The detection of cord bending can only determine whether the cord is bent and the approximate number of bends, and cannot accurately calculate the cord bending value. In the actual detection process, the judgment difference is often caused by equipment imaging problems, experience problems of the judges, etc.; secondly, the original rubbing measurement method currently used by tire manufacturers does not take into account the differences of each cord itself after transferring the actual arc section to a plane and rubbing it. That is, the original rubbing measurement method is used to measure different cords on the section, and the measurement results are different. In the early stage of product development, it is necessary to accurately grasp the cord bending value and make adjustments to the plan according to the bending situation.

[0004] The deficiency of the existing technology is that one of the current detection methods for determining whether the cord of a full-steel radial tire is bent is X-ray detection. The X-ray image is scrolled at a certain speed on the display, and the inspector visually determines the bending condition of the product cord. When further judgment is needed, the X-ray image must be printed out, the highest and lowest points of the cord bending on the image must be found, a horizontal straight line is drawn through the two points, and the number of cord roots between the two straight lines is calculated. The output result is the number of bent cords, and the cord bending value and degree of bending cannot be accurately calculated. In addition, during the X-ray detection and judgment process, misjudgment is often made due to equipment imaging problems (such as image deformation, uneven brightness of the image) and experience problems of the judges, which causes difficulties in the product development process.

[0005] Another commonly used method is the original rubbing measurement method. The measurement process involves removing the inner lining of the cross section, cutting a certain width of rubbing paper, and rubbing the cross section of the cord curve. A complete cord is randomly selected from the rubbing, and the intersection of the two ends of the cord with the measurement start and end lines is connected to form the measurement reference line. The maximum vertical distance between the cord and the reference line is the cord curvature. After measuring the maximum curvature, the cord curvature degree is calculated. This method can result in different measurement results depending on the location of the cord. That is, different cords selected on the same cross section will produce inconsistent measurement results. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art. To achieve the above purpose, a method for measuring the curvature of the carcass cord of an all-steel radial tire is adopted to solve the problems raised in the above background technology.

[0007] A method for measuring the curvature of a carcass cord of an all-steel radial tire comprises the following steps:

[0008] Step S1: Cut the tire to be tested into a flat cross section according to a standard thickness, and establish a global coordinate reference by combining symmetric marking technology;

[0009] Step S2: removing the inner liner using a non-destructive stripping technique to obtain a complete carcass cord, and connecting the front and back marking points using a physical or optical method to form a measurement reference line to establish a spatial coordinate system;

[0010] Step S3: using carbon powder to enhance contrast and tension-free attachment of adhesive rubbing paper, the three-dimensional cord morphology is accurately mapped into a two-dimensional plane rubbing image, and a standardized measurement data source is generated by transfer and fixation;

[0011] Step S4: Based on the plane rubbing diagram, the carcass cord curvature is obtained through geometric modeling and trigonometric calculation, and the curvature degree is calculated and converted into non-destructive quantitative analysis of the cord deformation and engineering parameter output.

[0012] As a further solution of the present invention: the specific steps in step S1 include:

[0013] Step S11: using precision cutting equipment to cut the tire into sections according to a preset thickness to ensure that the cross section is flat;

[0014] Step S12: removing cutting burrs by mechanical or manual grinding to make the material boundaries of the carcass cord and the inner liner clear for confirming and marking the measurement points;

[0015] Step S13: Mark the measurement start and end points on the front and back bead areas of the cross section respectively, and use a coordinate positioning tool to confirm that the marked points on the front and back are symmetrical to establish a baseline.

[0016] As a further solution of the present invention: the specific steps in step S2 include:

[0017] Step S21: using a special tool to remove the inner liner layer on the inside of the cross section, leaving only the exposed carcass cords;

[0018] Step S22: Connect the front and back marking points into a straight line by physical marking or laser projection to form the upper and lower mold measurement reference lines for establishing a spatial coordinate system.

[0019] As a further solution of the present invention: the specific steps in step S3 include:

[0020] Step S31: evenly cover the surface of the carcass cord with carbon powder, and enhance the contrast of the cord profile by utilizing the adhesion of the carbon powder;

[0021] Step S32: Attach the rubbing paper with an adhesive coating to the inner side of the cross section along the reference line without tension, and use a rolling tool to make the paper surface and the cord closely contact each other to achieve accurate mapping of the three-dimensional cord to the two-dimensional image;

[0022] Step S33: peel off the rubbing paper and lay it flat on white paper, re-mark the reference line, generate a two-dimensional rubbing map consistent with the real object, and obtain a plane rubbing map, which is used as a standardized data source for plane measurement.

[0023] As a further solution of the present invention: the specific steps in step S4 include:

[0024] Step S41: Select the uppermost and lowermost symmetrical cords on the rubbing image, and connect their intersection points with the reference line to form two measurement reference lines as a reference frame for calculating the bending amount;

[0025] Step S42: Locate the midpoint of the maximum cord bending point and the midpoint of the reference line, measure the vertical distance between the two, and obtain the cord bending amount β value, which is used to quantify the degree of cord center deviation;

[0026] Step S43: Using the cord bending amount β as a right-angled side and combining it with the reference line length to construct a right triangle, and calculating the bending degree α by the inverse tangent function to accurately characterize the cord deformation angle.

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

[0028] By adopting the above technical solution, a full-process approach involving standardized cross-section cutting, symmetrical marking of the front and back surfaces, non-destructive stripping of the inner liner to expose the carcass cords, carbon powder-enhanced contrast rubbing, and geometric modeling is achieved to accurately measure the bending deformation of tire cords. The method uses the center offset of two symmetrical cords to accurately measure the amount and degree of cord curvature, resolving the problems of X-ray inspection's inability to calculate the specific cord curvature value and degree, as well as the inaccurate measurement of the original rubbing measurement method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings:

[0030] Figure 1 A schematic diagram of the steps of a cord bending amount measurement method disclosed in an embodiment of the present application;

[0031] Figure 2 A flowchart of a cord bending amount measurement method according to an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the front and back cross-section of the tire bead structure of the embodiment disclosed in this application;

[0033] Figure 4 Schematic diagram of the upper and lower mold start and end lines of the embodiment disclosed in this application;

[0034] Figure 5 A schematic diagram of the upper and lower mold measurement reference lines of the embodiment disclosed in this application;

[0035] Figure 6 This is a schematic diagram of the maximum bending position of the cord in the embodiment disclosed in this application. DETAILED DESCRIPTION

[0036] 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.

[0037] Please refer to Figure 1 and Figure 2 In an embodiment of the present invention, a method for measuring the curvature of a carcass cord of an all-steel radial tire comprises:

[0038] Step S1: Cut the tire to be tested into flat sections according to the standard thickness, and establish a global coordinate reference by combining symmetry marking technology. The specific steps include:

[0039] Step S11: using precision cutting equipment to cut the tire into sections according to a preset thickness to ensure that the cross section is flat;

[0040] Step S12: removing cutting burrs by mechanical or manual grinding to make the material boundaries of the carcass cord and the inner liner clear for confirming and marking the measurement points;

[0041] Step S13: Mark the measurement start and end points on the front and back bead areas of the cross section respectively, and use a coordinate positioning tool to confirm that the marked points on the front and back are symmetrical to establish a baseline.

[0042] In the specific implementation steps, such as Figure 3 The figure shows the schematic diagram of the bead structure on the front and back of the cross section. According to the standard requirements, the tire is cut into sections of a certain thickness. The front and back of the section are polished to make the starting and ending points of each component material clearly visible. The upper and lower die measurement starting and ending points A and B are accurately marked on the bead area on the front of the section. The upper and lower die measurement starting and ending points a and b are marked at the corresponding positions on the bead area on the back of the section.

[0043] Step S2: Use non-destructive stripping technology to remove the inner liner to obtain a complete carcass cord, and connect the front and back marking points by physical or optical methods to form a measurement reference line to establish a spatial coordinate system. The specific steps include:

[0044] Step S21: using a special tool to remove the inner liner layer on the inside of the cross section, leaving only the exposed carcass cords;

[0045] Step S22: Connect the front and back marking points into a straight line by physical marking or laser projection to form the upper and lower mold measurement reference lines for establishing a spatial coordinate system.

[0046] In this embodiment, Figure 4 The figure shows the start and end lines of the upper and lower molds. In the figure, the inner liner on the inside of the cross section is removed to completely expose the carcass cords. Aa and Bb are connected respectively to form the measurement start and end lines on the upper and lower molds.

[0047] Step S3: Using carbon powder to enhance contrast and tension-free adhesive rubbing paper, the three-dimensional cord shape is accurately mapped into a two-dimensional flat rubbing image, and a standardized measurement data source is generated by transfer and fixation. The specific steps include:

[0048] Step S31: evenly cover the surface of the carcass cord with carbon powder, and enhance the contrast of the cord profile by utilizing the adhesion of the carbon powder;

[0049] Step S32: Attach the rubbing paper with an adhesive coating to the inner side of the cross section along the reference line without tension, and use a rolling tool to make the paper surface and the cord closely contact each other to achieve accurate mapping of the three-dimensional cord to the two-dimensional image;

[0050] Step S33: peel off the rubbing paper and lay it flat on white paper, re-mark the reference line, generate a two-dimensional rubbing map consistent with the real object, and obtain a plane rubbing map, which is used as a standardized data source for plane measurement.

[0051] In this embodiment, a soft-bristled brush is dipped in an appropriate amount of carbon powder and evenly applied to the exposed carcass cord. A rubbing paper with an adhesive side facing downward is attached to the carcass cord coated with carbon powder along the starting line of the upper mold section. The rubbing paper should not be stretched or folded during the attachment process, and the thickness and width of the cross section should be completely covered. An auxiliary tool is used to press the rubbing paper and the cord together to ensure full contact between the two, so that the trajectory of each cord can be clearly reproduced on the rubbing paper. After completing the above operations, the rubbing paper is carefully peeled off and transferred, and flatly applied to a white paper prepared in advance, marking the upper and lower mold positions. The start and end lines of the upper and lower mold ends are redrawn to obtain a rubbing pattern consistent with the product cord trajectory.

[0052] like Figure 5 The figure shows a schematic diagram of the upper and lower mold measurement reference lines. The bend amount β and degree α are measured on the flat rubbing. Two complete symmetrical cords, at the top and bottom of the rubbing, are taken and connected to the intersection of the two cords with the start and end lines of the upper and lower molds to form two measurement reference lines.

[0053] In this step, only the two complete symmetrical cords at the top and bottom are selected as an example for illustration. In actual operation, other groups of symmetrical cords can also be selected for rubbing. It has been verified that the results of measuring other groups of symmetrical cords according to this technical solution are the same, which also shows that this technical solution is not affected by the selection of cords and can accurately measure the actual bending of the rubbing cords.

[0054] Step S4: Based on the plane rubbing diagram, the carcass cord curvature is obtained through geometric modeling and trigonometric calculations, and the curvature degree is calculated and converted into non-destructive quantitative analysis of cord deformation and engineering parameter output. The specific steps include:

[0055] Step S41: Select the uppermost and lowermost symmetrical cords on the rubbing image, and connect their intersection points with the reference line to form two measurement reference lines as a reference frame for calculating the bending amount;

[0056] Step S42: Locate the midpoint of the maximum cord bending point and the midpoint of the reference line, measure the vertical distance between the two, and obtain the cord bending amount β value, which is used to quantify the degree of cord center deviation;

[0057] Step S43: Using the cord bending amount β as a right-angled side and combining it with the reference line length to construct a right triangle, and calculating the bending degree α by the inverse tangent function to accurately characterize the cord deformation angle.

[0058] In this embodiment, Figure 6The figure shows the maximum cord bending position. Find the maximum cord bending position, and find the cord midpoint c and the midpoint d of the two reference lines at the maximum bending position. The distance between c and d is called the "cord center offset", that is, the bending amount β value; using β as a right angle, draw horizontal lines to the upper and lower dies respectively to construct a right triangle, and calculate the bending degree α of the upper and lower dies. 上 and α 下 ;

[0059] 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 method for measuring the curvature of the carcass cord of a full steel radial tire, characterized in that: The following steps are involved: Step S1: Cut the tire to be tested into a flat cross section according to a standard thickness, and establish a global coordinate reference by combining symmetric marking technology; Step S2: removing the inner liner using a non-destructive stripping technique to obtain a complete carcass cord, and connecting the front and back marking points using a physical or optical method to form a measurement reference line to establish a spatial coordinate system; Step S3: using carbon powder to enhance contrast and tension-free attachment of adhesive rubbing paper, the three-dimensional cord morphology is accurately mapped into a two-dimensional plane rubbing image, and a standardized measurement data source is generated by transfer and fixation; Step S4: Based on the plane rubbing diagram, the carcass cord curvature is obtained through geometric modeling and trigonometric calculation, and the curvature degree is calculated and converted into non-destructive quantitative analysis of the cord deformation and engineering parameter output.

2. The method for measuring the curvature of the carcass cord of a full steel radial tire according to claim 1, characterized in that: The specific steps in step S1 include: Step S11: using precision cutting equipment to cut the tire into sections according to a preset thickness to ensure that the cross section is flat; Step S12: removing cutting burrs by mechanical or manual grinding to make the material boundaries of the carcass cord and the inner liner clear for confirming and marking the measurement points; Step S13: Mark the measurement start and end points on the front and back bead areas of the cross section respectively, and use a coordinate positioning tool to confirm that the marked points on the front and back are symmetrical to establish a baseline.

3. The method for measuring the curvature of the carcass cord of a full steel radial tire according to claim 1, characterized in that: The specific steps in step S2 include: Step S21: using a special tool to remove the inner liner layer on the inside of the cross section, leaving only the exposed carcass cords; Step S22: Connect the front and back marking points into a straight line by physical marking or laser projection to form the upper and lower mold measurement reference lines for establishing a spatial coordinate system.

4. The method for measuring the curvature of the carcass cord of a full steel radial tire according to claim 1, wherein: The specific steps in step S3 include: Step S31: evenly cover the surface of the carcass cord with carbon powder, and enhance the contrast of the cord profile by utilizing the adhesion of the carbon powder; Step S32: Attach the rubbing paper with an adhesive coating to the inner side of the cross section along the reference line without tension, and use a rolling tool to make the paper surface and the cord closely contact each other to achieve accurate mapping of the three-dimensional cord to the two-dimensional image; Step S33: peel off the rubbing paper and lay it flat on white paper, re-mark the reference line, generate a two-dimensional rubbing map consistent with the real object, and obtain a plane rubbing map, which is used as a standardized data source for plane measurement.

5. The method for measuring the curvature of the carcass cord of a full steel radial tire according to claim 1, characterized in that: The specific steps in step S4 include: Step S41: Select the uppermost and lowermost symmetrical cords on the rubbing image, and connect their intersection points with the reference line to form two measurement reference lines as a reference frame for calculating the bending amount; Step S42: Locate the midpoint of the maximum cord bending point and the midpoint of the reference line, measure the vertical distance between the two, and obtain the cord bending amount β value, which is used to quantify the degree of cord center deviation; Step S43: Using the cord bending amount β as a right-angled side and combining it with the reference line length to construct a right triangle, and calculating the bending degree α by the inverse tangent function to accurately characterize the cord deformation angle.

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