Cord fabric layer control method

Abstract

The invention provides a cord fabric control method. The method comprises the following steps: selecting one specification, ensuring that the perimeter of a fitting drum is not changed, carrying out a penetration test by using centering corresponding to different cord extensions, carrying out light detection after vulcanization of an outer tire, storing a picture, measuring the penetration degree and the actual extensions by slicing, and making an adjustment plan for all other specifications on the basis of the obtained initial value of the cord extensions. And testing and confirming the optimal elongation rate, so that the elongation rate of the tire cord thread is just right, and the overall performance of the tire is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of tire manufacturing, and in particular to a cord layer control method. Background Art

[0002] The tire cord is a cloth-like material composed of multiple layers of cords arranged in parallel and bonded together by rubber. It is mainly used for the sidewall and carcass of the tire, providing lateral support and impact resistance of the tire, and maintaining the shape and size of the tire. It is usually composed of multiple layers, and each layer of cords is arranged at a specific angle to enhance the strength of the tire in different directions. The cord is the basic unit of the tire cord. 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 skeleton role in the tire. They provide basic structural strength and wear resistance for the tire.

[0003] The cord stretch rate is a very important parameter in the design, production and use of tires. If the stretch rate is too small, it will cause cord bending and uneven tires in the production process, affecting the product qualification rate. Tires with too small stretch rates are prone to defects such as shoulder voids during use, and have low rigidity, affecting driving performance. If the stretch rate is too large, it will cause excessive penetration of cord steel wires into the transition layer. The penetration of cords into the transition layer will reduce the adhesion between the cord steel wires and the transition layer steel wires, leading to shoulder voids and other problems after use. In severe cases, wire exposure may occur, affecting safety. Therefore, it is necessary to explore and study a balance point so that the stretch rate of the carcass cord is just right to ensure the overall performance of the tire.

[0004] The shortcomings of the existing technology are that the cord stretching rate in tire molding design is entirely based on experience and feeling, and there is no set of perfect design criteria, which will have a great impact on production, resulting in high penetration and high shoulder defect refund rate, and the construction needs to be revised repeatedly, resulting in a waste of time and cost. The previous production specifications of Guizhou Tire Co., Ltd. had a non-irradiated inner liner penetration of more than 50%, and a high shoulder defect refund rate.

[0005] To this end, the research team proposed a design criterion for the cord stretch rate during tire molding design. Summary of the invention

[0006] In order to solve the problems mentioned in the background technology, the present invention provides a cord layer control method to reduce the waste of time and cost caused by high penetration and high shoulder defect refund rate.

[0007] The present invention provides a cord layer control method, comprising the following steps:

[0008] S1 counts the inner lining penetration of existing specifications under the current cord stretch rate;

[0009] S2 selects a specification as the initial confirmation specification, tests the lining layer with irradiation process and non-irradiation process, and determines the process to be used for subsequent verification;

[0010] S3 selects an initial specification based on the initial confirmed specification, calculates the theoretical elongation corresponding to different alignments, uses the process determined by S2, conducts a penetration test, and measures the actual penetration degree and actual elongation;

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

[0012] S5 adjusts the centering of each specification based on the range of the best radial stretch value obtained by S4, adjusts the stretch to the range of the best radial stretch value and outputs the theoretical centering, and performs a penetration test to confirm; S6 collects statistics on the corresponding cord stretch of each specification after the centering adjustment to confirm its best stretch.

[0013] The S2 non-irradiation process is to directly extrude the transition layer rubber material and then compound it with the airtight layer; the irradiation process is to extrude the transition layer rubber material and then irradiate it with an electron beam and then compound it with the airtight layer.

[0014] The penetration test was conducted on the basis of reducing the centering of the wire ring by 2mm and 4mm respectively, and the specific process is as follows:

[0015] S31 measures the actual elongation of the specification;

[0016] S32: White glue is applied to the transition layer and the upper surface of the carcass cord layer respectively, and the position and angle of applying white glue to the transition layer and the cord layer are consistent;

[0017] S33 After it is completely dry, it is molded and the positions for brushing the glue are marked on the molded tire blank;

[0018] S34 After the tire is vulcanized, the finished tire and the normal tire are inspected on the same tire X-ray inspection machine and the pictures are kept to compare whether the curvature of the carcass cord has been improved;

[0019] S35 slices the rubber slurry positions of the test tire and normal tire respectively to measure the penetration degree.

[0020] Furthermore, in said S32, the white glue is applied in a small amount and multiple times, and after the first layer of glue is dry, it is repeatedly applied 2 to 3 times to ensure that the white glue line can be clearly seen on the same finished product section.

[0021] The actual elongation measurement process is specifically as follows:

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

[0023] S312 puts the scanned section into CAD at a ratio of 1:1 to measure the steel cord curve;

[0024] S313 measurement starts from the inner end point of the cross-section wire ring, where the inner end point is recorded as b, and the measurement is carried out 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 recorded as a, and the value of 2ab is obtained, where 2ab represents the curve length of the steel cord inside the wire rings on both sides of the finished tire;

[0025] S314 2ab / The actual left and right sum of the wire ring alignment measured during tire molding, the ratio obtained is multiplied by 100% to obtain the actual tire cord stretch rate.

[0026] The penetration degree measurement process is specifically as follows:

[0027] S351 takes 50*50mm sections at the shoulder parting point and the maximum section width of the sidewall;

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

[0029] S353 puts the scanned image into CAD at a 1:1 ratio, and uses the "mark" tool to measure the height between the white line on the upper surface of the steel wire and the lowest white line between the left and right steel wires, recorded as c, and the white line on the upper surface of the steel wire and the white line on the lower surface, recorded as d;

[0030] S354: Divide c measured by S353 by d and multiply by 100% to get the degree of penetration.

[0031] Furthermore, after the penetration test is performed on S5 to confirm, if the penetration level is serious, additional verification is performed.

[0032] As described in S6, the centering adjustment is performed for each specification, and the actual elongation is greater than the highest value in the range of the optimal radial elongation value without direct adjustment. First, an actual penetration test is carried out to confirm. If the degree of penetration is serious, additional centering verification is performed.

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

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

[0035] 2. Based on the best cord stretch rate, a survey of existing specifications can be conducted, and specifications that do not meet the requirements can be adjusted and improved to improve product quality. After the improvement, the penetration rate of the lining layer of the current production specifications has been reduced from 50% to 0%-10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the statistical analysis of the penetration degree and the cord bending degree in Example 1, a is the elongation rate <1%, b is the elongation rate ≥1% and <1.5%, c is the elongation rate ≥1.5% and ≤2%, and de is the elongation rate >2%;

[0037] Figure 2 A flow chart of an optimal cord stretching method for determining cord steel wire penetration degree according to an embodiment of the present invention;

[0038] Figure 3 This is a flow chart of a penetration test according to an embodiment of the present invention;

[0039] Figure 4 This is a flow chart of actual elongation measurement in an embodiment of the present invention;

[0040] Figure 5 This is a flow chart of penetration degree measurement according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the internal structure of a tire according to an embodiment of the present invention;

[0042] Figure 7 Schematic diagram of the curvature of the tire cord according to an embodiment of the present invention.

[0043] Explanation of the accompanying drawings: 1 upper tread rubber, 2 lower tread rubber, 3 shoulder pad rubber, 4 belt layer isolation rubber, 5 airtight layer rubber, 6 transition layer rubber, 7 sidewall rubber, 8 toe outer end point isolation rubber, 9 soft apex rubber, 10 toe wear-resistant rubber, 11 hard apex rubber, 12 tire bead isolation rubber, 13 shoulder pad isolation rubber, A1# belt layer, B2# belt layer, C3# belt layer, D4# belt layer, E toe reinforcement layer, F carcass cord, G wire ring, H wire ring wrapping cloth, I nylon welt, a center of steel cord, b inner end point of wire ring. DETAILED DESCRIPTION

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

[0045] Example 1

[0046] See also Figure 2-Figure 5 , a cord layer control method, comprising the following steps:

[0047] S1 conducted statistics on the inner lining penetration of existing specifications under the current cord stretch rate. It was found that the stretch rates of different specifications vary greatly, and the cord penetration also varies greatly without any regularity.

[0048] S2 uses 12R22.5 as the initial confirmation specification. The irradiated liner layer, which is extruded from the transition layer rubber and then irradiated with a 50kgr dose of electron beam and then compounded with the airtight layer, and the non-irradiated liner layer, which is directly extruded and compounded with the airtight layer, are tested. After the test, the non-irradiated liner layer is sliced ​​and found to have serious permeation, while the irradiated liner layer can better reduce the degree of permeation. Therefore, it is decided to use irradiation for subsequent verification.

[0049] S3 selected 12R22.5 economic type as the initial specification, calculated the theoretical elongation corresponding to different alignments, used irradiation technology, conducted penetration tests, and measured the actual penetration degree and actual elongation;

[0050] The penetration test was conducted on the basis of reducing the centering of the wire ring by 2mm and 4mm respectively, and the specific process is as follows:

[0051] S31 measures the actual elongation of the specification;

[0052] S32: Apply white glue on the transition layer and the upper surface of the carcass cord layer respectively. The position and angle of applying white glue on the transition layer and the cord layer are consistent. Apply the white glue in small amounts and multiple times. After the first layer of glue is dry, apply it repeatedly for 3 times to ensure that the white glue line can be clearly seen on the same finished product section.

[0053] S33 After it is completely dry, it is molded and the positions for brushing the glue are marked on the molded tire blank;

[0054] After the S34 tire is vulcanized, the finished tire and the normal tire are inspected on the same German YXLON tire X-ray inspection machine and the pictures are kept to compare whether the curvature of the carcass cord has been improved;

[0055] S35 slices the rubber slurry positions of the test tire and normal tire respectively to measure the penetration degree.

[0056] The actual elongation measurement process is specifically as follows:

[0057] S311 completely exposes the steel cord fabric of the finished tire section on the surface and scans it with a section scanner;

[0058] S312 puts the scanned section into CAD at a ratio of 1:1 to measure the steel cord curve;

[0059] S313 Figure 6As shown, the measurement starts from the inner end point of the cross-section wire ring, where the inner end point is recorded as b, and the measurement is carried out 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 recorded as a, and the value of 2ab is obtained. 2ab represents the curve length of the steel cord inside the wire rings on both sides of the finished tire;

[0060] S314 2ab / The actual left and right sum of the wire ring alignment measured during tire molding, the ratio obtained is multiplied by 100% to obtain the actual tire cord stretch rate.

[0061] The penetration degree measurement process is specifically as follows:

[0062] S351 takes 50*50mm sections at the shoulder parting point and the maximum section width of the sidewall;

[0063] S352 places the cross-section steel wire on the cross-section scanner for 1:1 scanning;

[0064] S353 puts the scanned image into CAD at a 1:1 ratio, and uses the "mark" tool to measure the height between the white line on the upper surface of the steel wire and the lowest white line between the left and right steel wires, recorded as c, and the white line on the upper surface of the steel wire and the white line on the lower surface, recorded as d;

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

[0066] S4 statistically analyzed the actual penetration degree, cord bending degree and actual elongation result data obtained from the S3 penetration test. The S3 test results are shown in Table 1;

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

[0068]

[0069] See Figure 1 , respectively, the penetration degree and cord bending degree were statistically analyzed for the above elongation rates of <1%; 1%≤ and ≤1.5%; 1.5%≤ and 2%≤; >2%:

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

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

[0072] Figure 1 -c elongation ≥1.5% and ≤2%, no penetration, cord bending 2-3 steel wire spacing;

[0073] Figure 1 -d, Figure 1 -e elongation>2%, slight penetration, cord bending 1-2 wire spacing.

[0074] It is preliminarily determined that the optimal radial stretching ratio is between 1.5% and 2%.

[0075] like Figure 7 ,The dotted box in the figure represents the overall tire cord curvature, and the red box represents the curvature of the left and right sides respectively, using the overall cord curvature.

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

[0077] Table 2 Alignment adjustment plan for existing specifications

[0078]

[0079] Through experiments, assuming that the cord stretch rate is 1.5% to 2.0%, if the actual stretch rate is less than 1.5%, the wire ring alignment should be adjusted to keep the cord elongation between 1.5% and 2.0%, and ensure that the steel cord bending is within 2-3 steel wire spacings; if the actual cord stretch rate exceeds 2.0%, adjustment is required in combination with the shoulder cord bending 2-3 steel wire spacings and the penetration degree exceeds 20%.

[0080] S6 counts the corresponding stretch rates of the cord fabrics of each specification after centering adjustment to confirm the optimal stretch rate. The statistical results are shown in Table 3.

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

[0082]

[0083] Conclusion: Through the above adjustments, when the cord elongation is 1.5-2%, the permeability can be ensured to be 0-10%, and the number of cord bends can be ensured to be 1-3, ensuring the overall performance of the tire is balanced.

[0084] Although the present invention has been described in detail above by means of general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A cord layer control method, characterized in that: The steps include: S1 counts the inner lining penetration of existing specifications under the current cord stretch rate; S2 selects a specification as the initial confirmation specification, tests the lining layer with irradiation process and non-irradiation process, and determines the process to be used for subsequent verification; S3 selects an initial specification based on the initial confirmed specification, calculates the theoretical elongation corresponding to different alignments, uses the process determined by S2, conducts a penetration test, and measures the actual penetration degree and actual elongation; S4 performs statistical analysis on the actual penetration degree, cord bending degree and actual elongation result data obtained from the penetration test in S3 to preliminarily determine the range of the optimal radial elongation value; S5 adjusts the centering of each specification based on the range of the optimal radial elongation value obtained in S4, adjusts the elongation to the range of the optimal radial elongation value, outputs the theoretical centering, and performs a penetration test to confirm; S6 collects statistics on the corresponding stretch rates of the cords of each specification after centering adjustment to confirm the optimal stretch rate.

2. The cord layer control method according to claim 1, characterized in that: The S2 non-irradiation process is to directly extrude the transition layer rubber material and then compound it with the airtight layer; the irradiation process is to extrude the transition layer rubber material and then irradiate it with an electron beam and then compound it with the airtight layer.

3. The cord layer control method according to claim 1, characterized in that: The penetration test is specifically: S31 measures the actual elongation of the specification; S32: White glue is applied to the transition layer and the upper surface of the carcass cord layer respectively, and the position and angle of applying white glue to the transition layer and the cord layer are consistent; S33 After it is completely dry, it is molded and the positions for brushing the glue are marked on the molded tire blank; S34 After the tire is vulcanized, the finished tire and the normal tire are inspected on the same tire X-ray inspection machine and the pictures are kept to compare whether the curvature of the carcass cord has been improved; S35 slices the rubber slurry positions of the test tire and normal tire respectively to measure the penetration degree.

4. The cord layer control method according to claim 3, characterized in that: The penetration test was conducted on the basis of reducing the centering of the wire ring by 2mm and 4mm respectively.

5. The cord layer control method according to claim 3, characterized in that: In the above S32, the white glue is applied in a small amount and multiple times, and after the first layer of glue is dry, it is repeatedly applied 2 to 3 times to ensure that the white glue line can be clearly seen on the same finished product section.

6. The cord layer control method according to any one of claim 1 or claim 3, characterized in that: The actual elongation measurement is specifically: S311 completely exposes the steel cord fabric of the finished tire section on the surface and scans it with a section scanner; S312 puts the scanned section into CAD at a ratio of 1:1 to measure the steel cord curve; S313 measurement starts from the inner end point of the cross-section wire ring, where the inner end point is recorded as b, and the measurement is carried out 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 recorded as a, and the value of 2ab is obtained, where 2ab represents the curve length of the steel cord inside the wire rings on both sides of the finished tire; S314 2ab / The actual left and right sum of the wire ring alignment measured during tire molding, the ratio obtained is multiplied by 100% to obtain the actual tire cord stretch rate.

7. The cord layer control method according to any one of claim 1 or claim 3, characterized in that: The penetration degree is measured specifically as follows: S351 takes 50*50mm sections at the shoulder parting point and the maximum section width of the sidewall; S352 places the cross-section steel wire on the cross-section scanner for 1:1 scanning; S353 puts the scanned image into CAD at a 1:1 ratio, and uses the "mark" tool to measure the height between the white line on the upper surface of the steel wire and the lowest white line between the left and right steel wires, recorded as c, and the height between the white line on the upper surface of the steel wire and the white line on the lower surface, recorded as d; S354: Divide c measured by S353 by d and multiply by 100% to get the degree of penetration.

8. The cord layer control method according to claim 1, characterized in that: After the penetration test of S5 is confirmed, if the penetration level is serious, additional verification is performed.

9. The cord layer control method according to claim 1, characterized in that: As described in S6, the centering adjustment is performed for each specification, and the actual elongation is greater than the highest value in the range of the optimal radial elongation value without direct adjustment. First, an actual penetration test is carried out to confirm. If the degree of penetration is serious, additional centering verification is performed.

10. The cord layer control method according to claim 1, characterized in that: The S6 performs centering adjustment for each specification. If there are tires with the same specification but different tread patterns, only the tire with any one of the tread patterns is tested.

Images