High-elongation steel cord structure
By designing a multi-section steel cord structure and using welding joint and twisting technology, the problem of high-elongation steel cord breaking during extrusion production is solved, and the smooth passage of welding joints and the improvement of production efficiency is achieved.
Patent Information
- Application Number
- CN202421509646.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-28
- Publication Date
- 2025-05-30
- Estimated Expiration
- 2034-06-28
AI Technical Summary
During the tire production process, high elongation steel cords are prone to fracture due to wire laying tension and welding joints stuck in the extrusion process, and the prior art is difficult to effectively solve this problem.
A multi-stage steel cord structure is adopted connected through welding points. Each steel cord includes N strands, and each strand is formed by M single filaments twisted. The strands and monofilaments are twisted in the same direction. The twist distances of the intermediate and transition points are different to form a buffer area. The two ends of the welding points are twisted and then welded to control the quality and diameter of the welding points.
Through twisting and welding technology, the quality and twist distance of the welding joints are controlled to form a buffer area to avoid bulging and fractures before the welding joints, and improve the passing rate of steel cords in the extrusion process production.
Smart Images
Figure CN222923512U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of steel cord, in particular to a high elongation steel cord structure. Background Art
[0002] In the process of tire production and manufacturing, according to the different application parts of the tire, there are two production processes: zero-degree extrusion method and calendering method. Among them, the extrusion production process has higher requirements for high-elongation steel cord. Due to factors such as the pressure of the extruder, the extrusion speed, and the aperture of the extrusion plate, extrusion wire breakage problems will occur during the production process. To overcome the problem of extrusion wire breakage in the extrusion production method, generally, high-elongation steel cord without solder joints is provided for extrusion production, and high-elongation steel cord with solder joints is used for calendering production. However, even if high-elongation steel cord without solder joints is used for extrusion production, due to factors such as the influence of pay-off tension, the steel cord is displaced during the extrusion process, resulting in different lengths of the three strands of the steel cord, that is, strand displacement, which leads to extrusion wire breakage.
[0003] Therefore, Patent Document 1 proposes a pay-off device for high-elongation steel cord and a solution to the problem of strand displacement during twisting. By improving the pay-off device, strand displacement of multiple strands will not occur. However, this solution still cannot overcome the application of high-elongation steel cord with solder joints in calendering production. Therefore, it is necessary to improve the structure of high-elongation steel cord with solder joints.
[0004] Prior Art Documents
[0005] Patent Document 1: CN114575173A, a pay-off device for high-elongation steel cord and a solution to the problem of strand displacement during twisting Summary of the Utility Model
[0006] In view of the technical problems existing in the high elongation steel cord in the prior art, the first aspect of the present utility model provides a high elongation steel cord structure, including several sections of steel cord. Each adjacent two sections of steel cord are connected by soldering at the solder joint. Each section of the steel cord includes N strands, and each strand includes M single wires. The strands and single wires are twisted in the same direction. The twist pitch of the strand is Ls, and the twist pitch of the steel cord is Lc;
[0007] Each section of the steel cord includes an intermediate section and transition sections located at both ends of the intermediate section;
[0008] Among them, the twist pitch of the intermediate section is Lca, and the twist pitch of the transition section is Lcb, and Lcb is less than Lca.
[0009] Preferably, the diameter of the steel cord is D1, and the diameter of the solder joint is D2, and D2 ≤ 1.05D1.
[0010] Preferably, the twist pitch Lc of the steel cord is 3 - 10 mm.
[0011] Preferably, the ratio of the twist pitch Ls of the ply yarn to Lc is 0.5 to 1.
[0012] Preferably, the ratio of the twist pitch Lca of the middle section to the twist pitch Lcb of the transition section is 0.3 to 0.9.
[0013] Preferably, the twist pitch Lca of the middle section is 3 to 5 mm, and the twist pitch Lcb of the transition section is 6 to 10 mm.
[0014] Preferably, the diameter of the monofilament is 0.15 to 0.24 mm.
[0015] Preferably, the length of the transition section is 3 to 5 times the length of the solder joint.
[0016] Compared with the prior art, the advantages of the present utility model are as follows:
[0017] For the multi-segment steel cord structure connected by solder joints proposed in this application, twist and welding are performed at both ends of the solder joint through a twister. This not only better controls the quality of the solder joint but also makes the twist pitch smaller and the twisting tighter within a certain distance at both ends of the solder joint. During the extrusion pay-off test, when the cord is extruded and twisted and pushed to the front of the solder joint, the twisted section of the cord starts to loosen, forming a certain buffer area, enabling the solder joint to smoothly pass through the die hole. The situation of bulging and breaking during the extrusion production of the welded steel cord is better improved, making it possible to produce welded steel cord by the extrusion method. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present utility model will be described by way of example and with reference to the drawings, wherein:
[0019] Figure 1 is a schematic diagram of a high-elongation steel cord being stuck at the die opening in the prior art;
[0020] Figure 2 is a schematic diagram of the high-elongation steel cord structure shown in the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0021] In order to better understand the technical content of the present utility model, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.
[0022] Such as Figure 1As shown, in the extrusion method, the rubber is extruded through a die A with a diameter similar to that of the cord. High requirements are placed on the cord diameter and elongation. Once there is a welding point, it is more likely to get stuck and break at the die opening. Therefore, stricter control is required for the welding specifications and standards of high-elongation specifications.
[0023] Especially, stricter control is implemented on the solder joint quality and solder joint diameter compared to ordinary specifications to enable normal use at the customer's site. However, according to customer feedback, there are still cases where it breaks before the solder joint. Although the solder joint diameter can pass smoothly, before reaching the solder joint, the cord is squeezed, causing some of the twisting to be continuously squeezed and loosened forward, resulting in a structure B similar to a bulge and unable to pass through die A, leading to breakage.
[0024] The applicant found that during the extrusion process, the steel cord continuously advances forward. Once it reaches before the solder joint, the solder joint is a fixed point and cannot release the twisting forward anymore, thus forming a bulge structure B before the solder joint, resulting in breakage. By controlling the elongation and solder joint quality, this kind of solder joint breakage cannot be eliminated.
[0025] Combined with Figure 2 As shown, a first aspect of the present utility model provides a high-elongation steel cord structure, including several sections of steel cord 10. Each adjacent two sections of steel cord 10 are welded and connected through a solder joint 20. Each section of steel cord 10 includes N strands. Optionally, N is an integer from 2 to 7. Each strand includes M filaments. Optionally, M is an integer from 2 to 9. The strands and filaments are twisted in the same direction. The pitch of the strand is Ls, and the pitch of the steel cord 10 is Lc.
[0026] Optionally, high-elongation steel cords are usually structures such as 3×7, 3×4, 4×4, 4×6, etc., that is, they all include multiple strands, and each strand is formed by twisting multiple filaments. The diameter of the filament is 0.15 - 0.24 mm.
[0027] In an optional embodiment, the ratio of the pitch Ls of the strand to Lc is 0.5 to 1.
[0028] In this way, the pitch of the strand is smaller than that of the steel cord, which is beneficial to forming a high-elongation steel cord. In addition, the twisting directions of the strand and the filament are the same, which helps to obtain a steel cord with high strength, high breaking elongation, and high elastic modulus.
[0029] Further, each section of steel cord 10 includes an intermediate section 11 and transition sections 12 located at both ends of the intermediate section 11. The pitch of the intermediate section 11 is Lca, and the pitch of the transition section 12 is Lcb. Lcb is less than Lca.
[0030] Optionally, the ratio of the pitch Lca of the intermediate section 11 to the pitch Lcb of the transition section 12 is 0.3 - 0.9, and the pitch of the transition section 12 gradually increases from the solder joint position towards the intermediate section 11.
[0031] In this way, the two ends of the steel cord that need to be welded are twisted by a twister and then welded, so that the two ends of the steel cord are tightly twisted. In the extrusion pay-off test, when the cord is extruded and twisted to approach the solder joint, the twisted section of the cord starts to loosen and does not bulge. Therefore, a certain buffer zone is formed in the twisted area, which significantly improves the situation of bulging and breaking during twisting before the solder joint.
[0032] Optionally, the length of the transition section 12 is 3 to 5 times the length of the solder joint 20. In this way, the transition section 12 can provide a buffer and release area for the stress formed after extrusion of the middle section. Among them, the appropriate length of the transition section 12 can be determined according to the twist pitch ratio of the middle section 11 to the transition section 12 or the length of the middle section 11.
[0033] Furthermore, the diameter of the steel cord 10 is D1, and the diameter of the solder joint 20 is D2, where D2 ≤ 1.05D1.
[0034] By further controlling the diameter of the solder joint 20, when this steel cord is payed off by the extrusion method, it can pass through the die hole better, making it possible to produce the welded steel cord by the extrusion method.
[0035] In an optional embodiment, the twist pitch Lc of the steel cord 10 is 3 to 10 mm. Among them, the twist pitch Lca of the middle section 11 is 6 to 10 mm, and the twist pitch Lcb of the transition section 12 is 3 to 5 mm.
[0036] With a larger twist pitch of the middle section 11, the production efficiency can be improved, and the difficulty of twisting the transition section 12 can be reduced.
[0037] Combining the above embodiments, the multi-section steel cord structure connected by solder joints proposed in this application is twisted by a twister and then welded at both ends of the solder joint. This not only better controls the quality of the solder joint, but also makes the twist pitch smaller and the twisting tighter within a certain distance at both ends of the solder joint. In the extrusion pay-off test, when the cord is extruded and twisted to approach the solder joint, the twisted section of the cord starts to loosen, forming a certain buffer zone, enabling the solder joint to smoothly pass through the die hole. The situation of bulging and breaking during the production of the welded steel cord by the extrusion method is significantly improved, making it possible to produce the welded steel cord by the extrusion method.
[0038] Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Those with ordinary knowledge in the technical field to which the present utility model belongs can make various changes and modifications without departing from the spirit and scope of the present utility model. Therefore, the protection scope of the present utility model shall be determined by the scope defined in the claims.
Claims
1. A high elongation steel cord structure, characterized in that: The invention comprises a plurality of sections of steel cord (10), wherein each two adjacent sections of steel cord (10) are welded and connected via a welding point (20), each section of the steel cord (10) comprises N strands, each strand comprises M monofilaments, the strands and monofilaments are twisted in the same direction, the twist length of the strands is Ls, and the twist length of the steel cord (10) is Lc; Each section of the steel cord (10) comprises a middle section (11) and transition sections (12) located at both ends of the middle section (11); The lay length of the middle section (11) is Lca, the lay length of the transition section (12) is Lcb, and Lcb is smaller than Lca.
2. The high elongation steel cord structure according to claim 1, characterized in that: The diameter of the steel cord (10) is D1, the diameter of the welding point (20) is D2, and D2≦1.05D1.
3. The high elongation steel cord structure according to claim 1, characterized in that: The twist length Lc of the steel cord (10) is 3 to 10 mm.
4. The high elongation steel cord structure according to claim 3, characterized in that: The ratio of the lay lengths Ls to Lc of the strands is 0.5 to 1.
5. The high elongation steel cord structure according to claim 1, characterized in that: The ratio of the lay length Lca of the middle section (11) to the lay length Lcb of the transition section (12) is 0.3 to 0.
9.
6. The high elongation steel cord structure according to claim 3, characterized in that: The lay length Lca of the middle section (11) is 3 to 5 mm, and the lay length Lcb of the transition section (12) is 6 to 10 mm.
7. The high elongation steel cord structure according to claim 1, characterized in that: The diameter of the monofilament is 0.15-0.24 mm.
8. The high elongation steel cord structure according to any one of claims 1 to 7, characterized in that: The length of the transition section (12) is 3 to 5 times the length of the welding point (20).