A carcass control method

Abstract

The present invention provides a method for controlling the cord ply. Select a specification, ensure that the circumference of the building drum remains unchanged, conduct penetration tests for centering corresponding to different cord elongation rates, perform optical inspection on the cured tire and save the pictures, then slice the tire for measuring the penetration degree and the actual elongation rate. Based on the initial value of the cord elongation rate obtained, formulate adjustment plans for all other specifications, conduct tests and confirm their optimal elongation rates, so that the elongation rate of the carcass cord is just right to ensure the overall performance of the tire.

Description

Technical Field

[0001] The present invention relates to the technical field of tire manufacturing, and in particular to a method for controlling a ply. Background Art

[0002] A ply is a cloth-like material formed by arranging multiple layers of cords in parallel and bonding them together with rubber. It is mainly used for the sidewalls and carcasses of tires to provide lateral support and impact resistance for the tires, and to maintain the shape and size of the tires. It usually consists of multiple layers, and each layer of cords is arranged at a specific angle to enhance the strength of the tire in different directions. A cord is the basic unit that makes up a ply. It is a high-strength fiber or metal wire used to reinforce rubber materials. It can be made of different materials, such as nylon, polyester, steel wire, etc. It plays a skeletal role in the tire, providing basic structural strength and wear resistance for the tire.

[0003] The ply elongation rate is a very important parameter in the design, production, and use of tires. If the elongation rate is too small, it will cause defects such as ply bending and uneven inner liner in the production process, affecting the product qualification rate. Tires with too small an elongation rate are prone to defects such as shoulder voids during use, with relatively low stiffness and affecting driving performance. While if the elongation rate is too large, it will cause too many ply steel wires to penetrate into the transition layer. The penetration of the ply into the transition layer results in a decrease in the adhesion between the ply steel wires and the transition layer steel wires, leading to problems such as shoulder voids after use, and even wire exposure in severe cases, affecting safety. Therefore, it is necessary to explore and study a balance point to make the ply elongation rate of the carcass just right to ensure the overall performance of the tire.

[0004] The deficiencies of the prior art are that currently, when designing the tire shaping, the ply elongation rate depends entirely on experience and feeling, without a complete set of design criteria, which will have a greater impact on production, resulting in a high degree of penetration and a high rejection rate of shoulder voids. It is necessary to repeatedly revise the construction, causing waste of time and cost. Guizhou Tyre Co., Ltd. used to have a penetration degree of the non-irradiated inner liner exceeding 50% for previous production specifications, and the rejection rate of shoulder voids remained high.

[0005] Therefore, the research team proposed a design criterion for the ply elongation rate during tire shaping design. Summary of the Invention

[0006] To solve the problems mentioned in the background art, the present invention provides a method for controlling a ply, reducing the waste of time and cost caused by a high degree of penetration and a high rejection rate of shoulder voids.

[0007] The present invention provides a method for controlling a ply, including the following steps:

[0008] S1 Statistically analyze the penetration situation of the inner liner under the current ply elongation rate for existing specifications;

[0009] S2 Select a specification as the initial confirmation specification, conduct tests on the inner liner layer using the irradiation process and the non-irradiation process, and determine the process to be used for subsequent verification;

[0010] S3 Based on the initial confirmation specification, select an initial specification, calculate the theoretical elongation rate corresponding to different alignments, use the process determined in S2 to conduct a penetration test, and measure the actual penetration degree and actual elongation rate;

[0011] S4 Conduct statistical analysis on the actual penetration degree, cord bending degree, and actual elongation rate result data obtained from the penetration test in S3 to preliminarily determine the range of the optimal radial elongation rate value;

[0012] S5 Based on the range of the optimal radial elongation rate value obtained in S4, adjust the alignment of each specification, adjust the elongation rate to within the range of the optimal radial elongation rate value and output the theoretical alignment, and conduct a penetration test for confirmation; S6 Conduct statistics on the cord elongation rate corresponding to each specification after alignment adjustment, and confirm its optimal elongation rate.

[0013] The non-irradiation process in S2 is that the transition layer rubber compound is directly extruded and formed and then compounded with the airtight layer; the irradiation process is that the transition layer rubber compound is extruded and then compounded with the airtight layer after being irradiated by an electron beam.

[0014] The penetration test is conducted on the basis of reducing the bead alignment by 2 mm and 4 mm respectively. The specific process is as follows:

[0015] S31 Measure the actual elongation rate of this specification;

[0016] S32 Apply white rubber cement on the upper surfaces of the transition layer and the carcass cord fabric layer respectively. The positions and angles of applying white rubber cement on the transition layer and the cord fabric are the same;

[0017] S33 Wait until it is dry and then conduct forming, and mark it on the formed tire blank according to the position where the rubber cement is brushed;

[0018] S34 After the outer tire is vulcanized, conduct inspection on the finished tire and a normal tire on the same tire X-ray inspection machine and keep the pictures to compare whether there is improvement in the bending degree of the carcass cord fabric;

[0019] S35 Cut slices at the positions where the rubber cement is brushed on the experimental tire and the normal tire respectively, and measure the penetration degree.

[0020] Furthermore, in S32, the white rubber cement is applied in a small amount and multiple times. After the first layer of rubber cement is dry, brush it 2 - 3 times repeatedly to ensure that the white rubber cement line can be clearly seen under the same finished product cross-section.

[0021] The specific process for measuring the actual elongation rate is as follows:

[0022] S311 exposes the steel cord fabric of the cross-section of the experimental finished tire completely on the surface and scans it with a cross-section scanner;

[0023] S312 places the scanned cross-section 1:1 into CAD for measuring the curve of the steel cord fabric;

[0024] When measuring in S313, start from the inner end point of the cross-section steel wire ring, where the inner end point is denoted as b, and measure along the center of the steel cord fabric to the same position at the other end of the cross-section to end. The center of the steel cord fabric is denoted as a, and the value of 2ab is obtained. Here, 2ab represents the curve length of the inner steel cord in the inner side parts of the two steel wire rings of the finished tire;

[0025] S314 Divide 2ab by the sum of the left and right alignments actually measured during tire blank forming, and multiply the obtained ratio by 100% to get the actual cord fabric elongation rate of the tire.

[0026] The specific process for measuring the penetration degree is as follows:

[0027] S351 takes cross-sections of 50*50 mm at the shoulder parting and the maximum cross-section width of the tire side respectively;

[0028] S352 places the cross-section steel wire of the cross-cut on the cross-section scanner for 1:1 scanning;

[0029] S353 places the scanned picture in CAD at a 1:1 ratio, and uses the "dimensioning" tool to measure the height value between the white line on the upper surface of the steel wire and the lowest white line between the left and right two steel wires, denoted as c, and the white line on the upper surface and the white line on the lower surface of the steel wire, denoted as d;

[0030] S354 Divide c obtained by S353 measurement by d and multiply by 100% to get the penetration degree.

[0031] Furthermore, after the penetration test is confirmed in S5, if the penetration degree is serious, the alignment is increased for verification.

[0032] For the alignment adjustment of each specification in S6, those with the actual elongation rate greater than the highest value of the optimal radial elongation rate range are not directly adjusted. First, the actual penetration test is carried out for confirmation. If the penetration degree is serious, the alignment is increased for verification.

[0033] The beneficial effects of the present invention are as follows:

[0034] 1. The design method of the present invention can confirm the range of cord fabric elongation rate with the best penetration degree of the cord fabric steel wire, and output the reference design criteria for the cord fabric elongation rate, so that the elongation rate of the carcass cord is just right to ensure the overall performance of the tire.

[0035] 2. Based on the optimal cord elongation rate, a general survey can be conducted on existing specifications, adjust and improve the specifications that do not meet the requirements, improve product quality, and after improvement, the penetration degree of the inner liner of the current production specifications has decreased from 50% to 0%-10%. Description of the Drawings

[0036] Figure 1 Schematic diagram for statistical analysis of the penetration degree and cord bending degree in Example 1. a represents an elongation rate < 1%, b represents an elongation rate ≥ 1% and < 1.5%, c represents an elongation rate ≥ 1.5% and ≤ 2%, and d - e represents an elongation rate > 2%.

[0037] Figure 2 Flowchart of the method for determining the optimal cord elongation rate for the cord steel penetration degree in the embodiment of the present invention;

[0038] Figure 3 Flowchart of the penetration test in the embodiment of the present invention;

[0039] Figure 4 Flowchart of the actual elongation rate measurement in the embodiment of the present invention;

[0040] Figure 5 Flowchart of the penetration degree measurement in the embodiment of the present invention;

[0041] Figure 6 Schematic diagram of the internal structure of the tire in the embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the cord bending degree of the tire in the embodiment of the present invention.

[0043] Description of the reference numerals: 1 upper tread rubber, 2 lower tread rubber, 3 shoulder pad rubber, 4 belt layer separator rubber, 5 airtight layer rubber, 6 transition layer rubber, 7 sidewall rubber, 8 outer end point separator rubber of the bead, 9 soft triangular rubber, 10 bead wear-resistant rubber, 11 hard triangular rubber, 12 bead separator rubber, 13 shoulder pad separator rubber, A 1# belt layer, B 2# belt layer, C 3# belt layer, D 4# belt layer, E bead reinforcement layer, F carcass cord, G steel wire ring, H steel wire ring wrapper, I nylon strip, a center of the steel cord, b inner end point of the steel wire ring. Detailed Description of the Invention

[0044] The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0045] Example 1

[0046] Refer to Figures 2 - 5 , a cord layer control method, comprising the following steps:

[0047] S1 statistically analyzed the penetration of the inner liner layer under the current cord elongation rate of the existing specifications. It was found that there were significant differences in the elongation rates of different specifications, and there were also great differences in the cord penetration degree, showing no pattern.

[0048] S2 took the 12R22.5 specification as the initial confirmed specification. After the transition layer compound was extruded and irradiated with an electron beam dose of 50 kgr, it was then laminated with the airtight layer. An experiment was conducted with a non-irradiated inner liner layer that was directly extruded and formed from the transition layer compound and then laminated with the airtight layer. After the experiment, it was found through slicing that there were serious penetration phenomena in all non-irradiated inner liner layers, while the irradiated inner liner layer could better reduce the penetration degree. Therefore, it was decided to use irradiation for subsequent verification.

[0049] S3 selected the 12R22.5 economy type as the initial specification, calculated the theoretical elongation rates corresponding to different alignments, adopted the irradiation process, conducted penetration tests, and measured the actual penetration degree and actual elongation rate.

[0050] The above-mentioned penetration tests were conducted on the basis of reducing the bead alignment by 2 mm and 4 mm respectively. The specific process was as follows:

[0051] S31 measured the actual elongation rate of this specification.

[0052] S32 coated white slurry on the upper surfaces of the transition layer and the carcass cord layer respectively. The positions and angles of coating the white slurry on the transition layer and the cord were the same. The white slurry was applied in small amounts and multiple times. After the first layer of slurry dried, it was brushed 3 more times to ensure that the white slurry line could be clearly seen under the same finished product cross-section.

[0053] S33 waited until it was completely dry and then carried out forming, and marked it on the formed tire blank according to the position where the slurry was brushed.

[0054] S34 after the outer tire was vulcanized, the finished tire and a normal tire were inspected on the same German YXLON tire X-ray inspection machine and the pictures were retained to compare whether there was any improvement in the bending degree of the carcass cord.

[0055] S35 sliced the positions where the slurry was brushed on the experimental tire and the normal tire respectively, and measured the penetration degree.

[0056] The specific process for measuring the actual elongation rate was as follows:

[0057] S311 completely exposed the steel cord of the experimental finished tire cross-section on the surface and scanned it with a cross-section scanner.

[0058] S312 placed the scanned cross-section 1:1 into CAD for measuring the steel cord curve.

[0059] S313 As Figure 6As shown, during measurement, start from the inner end point of the cross-section steel wire ring, where the inner end point is denoted as b, and measure along the center of the steel wire cord until reaching the same position at the other end of the cross-section. The center of the steel wire cord is denoted as a, and the value of 2ab is obtained. 2ab represents the curve length of the steel wire cord inside the finished tire at the inner side parts of the two steel wire rings.

[0060] S314 Divide 2ab by the sum of the left and right alignments of the steel wire rings actually measured during tire embryo forming, and multiply the obtained ratio by 100% to get the actual cord elongation rate of the tire.

[0061] The specific process for measuring the penetration degree is as follows:

[0062] S351 Take cross-sections of 50*50mm at the tire shoulder parting and the maximum cross-section width of the tire side respectively.

[0063] S352 Place the cross-section steel wire of the cross-section on the cross-section scanner for 1:1 scanning.

[0064] S353 Place the scanned picture in CAD at a 1:1 ratio, and use the "dimension" tool to measure the height value between the white line on the upper surface of the steel wire and the lowest white line between the left and right two steel wires, denoted as c, and the white line on the upper surface and the white line on the lower surface of the steel wire, denoted as d.

[0065] S354 Divide c obtained by S353 by d and multiply by 100% to get the penetration degree.

[0066] S4 Conduct statistical analysis on the actual penetration degree, cord bending degree, and actual elongation rate result data obtained from the S3 penetration test. The results of the S3 experiment are shown in Table 1.

[0067] Table 1 Penetration test results for 12R22.5 specification

[0068]

[0069] See Figure 1 , respectively conduct statistical analysis on the penetration degree and cord bending degree for the above elongation rates of <1%; 1% ≤ and ≤ 1.5%; 1.5% ≤ and 2% ≤; >2%:

[0070] Figure 1 -a The elongation rate <1%, no penetration, but the cord bending > 5 steel wire spacings;

[0071] Figure 1 -b The elongation rate ≥1% and <1.5%, no penetration, but the cord bending > 3 steel wire spacings;

[0072] Figure 1 -c The elongation rate ≥1.5% and ≤2%, no penetration, the cord bending is 2 - 3 steel wire spacings;

[0073] Figure 1 -d, Figure 1 -e Elongation rate>2%, slight penetration, cord bending at a distance of 1 - 2 steel wires.

[0074] Thus, the optimal value of the radial elongation rate is preliminarily determined to be between 1.5% and 2%.

[0075] Such as Figure 7 , the dashed box in the figure represents the overall cord bending degree of the tire, and the red boxes respectively represent the bending degrees on the left and right sides, adopting the overall cord fabric bending degree.

[0076] S6 obtains a more appropriate radial elongation rate of between 1.5% and 2% from S4. Based on this elongation rate, the theoretical elongation rate of the existing specifications is adjusted, the centering adjustment is carried out for each specification, the elongation rate is adjusted to between 1.5% and 2%, and the theoretical centering is output. Among them, those with an elongation rate > 2% are not directly adjusted, and the actual penetration test is carried out for confirmation. If the penetration degree is serious, the centering is increased for verification. The results are shown in Table 2;

[0077] Table 2 Centering adjustment plan for existing specifications

[0078]

[0079] Through experiments, assuming that the cord fabric elongation rate is 1.5% - 2.0%, for those with an actual elongation rate less than 1.5%, the centering of the bead is adjusted to keep the cord fabric elongation rate between 1.5% and 2.0%, ensuring that the cord fabric bends at a distance of 2 - 3 steel wires; for those with an actual cord fabric elongation rate exceeding 2.0%, combined with the cord bending at a distance of 2 - 3 steel wires at the shoulder and a penetration degree exceeding 20%, adjustment is required.

[0080] S6 statistically analyzes the cord fabric elongation rates corresponding to the centering adjustments of each specification to confirm its optimal elongation rate. The statistical results are shown in Table 3.

[0081] Table 3 Statistics of actual effects after centering adjustment of each specification

[0082]

[0083] Conclusion: Through the above adjustments, when ensuring the cord elongation rate of 1.5 - 2%, the penetration rate can be ensured to be between 0 - 10%, and at the same time, the number of cord bends is ensured to be between 1 - 3, ensuring the balance of the comprehensive performance of the tire.

[0084] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A carcass ply control method, characterized in that, It includes the following steps: S1. Statistically analyze the penetration of the inner liner layer under the current cord elongation rate for the existing tire specifications; S2. Select a tire specification as the initial confirmation specification, conduct tests on the inner liner layer using the irradiation process and the non-irradiation process, and determine the process to be used for subsequent verification; S3. Based on the initially confirmed tire specification, select an initial specification, calculate the theoretical elongation rate corresponding to different centering, use the process determined in S2 to conduct a penetration test, and measure the actual penetration degree and actual elongation rate; The specific measurement of the actual elongation rate is as follows: S311. Completely expose the cross-section steel cord of the experimental finished tire on the surface and scan it with a cross-section scanner; S312. Place the scanned cross-section 1:1 into CAD for measuring the curve of the steel cord; S313. When measuring, start from the inner end point of the cross-section steel cord, where the inner end point is denoted as b, measure along the center of the steel cord to the same position at the other end of the cross-section, where the center of the steel cord is denoted as a, and obtain the value of 2ab. Here, 2ab represents the curve length of the inner steel cord of the finished tire at the inner side parts of the two steel cords; S314. Divide 2ab by the sum of the left and right centering actually measured during tire embryo forming, and multiply the obtained ratio by 100% to get the actual cord elongation rate of the tire; The specific penetration test is as follows: S31. Measure the actual elongation rate of the initial tire specification; S32. Apply white sizing paste on the upper surfaces of the transition layer and the carcass ply respectively. The positions and angles of applying the white sizing paste on the transition layer and the ply are the same; S33. After drying, perform forming and mark it on the formed tire embryo according to the position where the sizing paste is applied; S34. After vulcanizing the outer tire, inspect the finished tire and a normal tire on the same tire X-ray inspection machine and retain the pictures to compare whether there is an improvement in the bending degree of the carcass ply; S35. Cut slices at the positions where the sizing paste is applied on the experimental tire and the normal tire respectively, and measure the actual penetration degree; The specific measurement of the actual penetration degree is as follows: S351. Take cross-sections of 50*50mm at the shoulder parting and the maximum cross-section width of the tire side respectively; S352. Place the cross-cut cross-section steel on the cross-section scanner for 1:1 scanning; S353. Place the scanned picture in CAD at a 1:1 ratio, and use the marking tool to measure the height value of the white line on the upper surface of the steel cord and the lowest white line between the left and right two steel cords, denoted as c, and the distance between the white line on the upper surface and the white line on the lower surface of the steel cord, denoted as d; S354. Divide c obtained by S353 by d and multiply by 100% to obtain the actual penetration degree; S4. Statistically analyze the results data of the actual penetration degree, ply bending degree, and actual elongation rate obtained from the S3 penetration test to initially determine the range of the optimal radial elongation rate value; S5. Based on the range of the optimal radial elongation rate value obtained in S4, adjust the centering of the existing tire specifications, adjust the elongation rate to within the range of the optimal radial elongation rate value and output the theoretical centering, conduct a penetration test for confirmation, and if the penetration degree is serious, increase the centering for verification; S6. Statistically analyze the cord elongation rate corresponding to the existing tire specifications after centering adjustment, and confirm its optimal elongation rate. Among them, those with an actual elongation rate greater than the highest value of the optimal radial elongation rate range are not directly adjusted. First, conduct a penetration test in actuality. If the actual penetration degree is severe, increase the centering for verification.

2. The cord ply control method according to claim 1, characterized in that In step S2, the non-irradiation process is that the transition layer rubber compound is directly extruded and formed and then compounded with the airtight layer; the irradiation process is that the transition layer rubber compound is extruded, irradiated by an electron beam, and then compounded with the airtight layer.

3. The cord ply control method according to claim 1, wherein The penetration test is carried out on the basis of reducing the centering of the bead ring by 2 mm and 4 mm respectively.

4. The cord ply control method according to claim 1, wherein In S32, the white cement is applied in a small amount and multiple times. After the first layer of cement dries, brush it repeatedly 2 - 3 times to ensure that the white cement line can be clearly seen under the same finished product cross-section after application.

5. The cord ply control method according to claim 1, characterized in that In step S6, the centering of the existing tire specifications is adjusted. If there are tires of the same specification but different tread patterns, only conduct experiments on the tires of any one tread pattern.

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