3+N Metal Cord In-Situ Rubberization for Tire Belt Corrosion
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Solution Overview
Problem
Three-plus-N (3+N) metal cords used in tire belts face challenges such as incomplete rubber penetration due to central capillary channels, leading to corrosion and reduced endurance, and existing in-situ rubberization processes are inefficient and costly, with issues like excessive rubber usage and manufacturing complexity.
Innovation Solution
A novel 3+N metal cord with a specific structure and manufacturing process, where the inner layer is sheathed with diene rubber, ensuring the central channel and gaps are filled with rubber, reducing air permeability and enhancing corrosion resistance, using a single extrusion head for efficient production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 3+N metal cords are used with central capillary channels, then manufacturing is simpler and rubber penetration is easier, but air permeability increases leading to corrosion and reduced endurance
Solution Approach 1:
The invention removes the central capillary channel from the cord structure by filling it with rubber during in-situ rubberization. This extraction of the harmful empty channel eliminates the pathway for air and moisture penetration, thereby preventing corrosion and improving endurance while maintaining the simple 3+N construction.
Solution Approach 2:
The invention changes the physical state and distribution of rubber within the cord structure. By controlling rubberization parameters, the rubber fills the central capillary and inter-wire spaces, transforming the structure from permeable to impermeable, thereby eliminating corrosion pathways without changing the basic cord architecture.
2Reliability
If in-situ rubberization is implemented to fill central channels, then corrosion resistance improves, but rubber usage increases and manufacturing complexity increases
Solution Approach 1:
The invention employs self-service rubberization where the cord structure itself facilitates the rubberization process. The 3+N construction with its specific wire arrangement allows rubber to naturally penetrate and fill the central capillary during normal manufacturing operations, eliminating the need for additional complex equipment or multi-step processes while achieving complete corrosion protection.
3Reliability
If in-situ rubberization is used to ensure complete penetration, then corrosion resistance improves, but excessive rubber usage occurs leading to oozing and cost increase
Solution Approach 1:
The invention applies partial rubberization targeted specifically at the central capillary and inter-wire spaces rather than excessive rubberization of the entire cord. By controlling the rubberization process to fill only the necessary voids, the invention achieves complete corrosion protection with optimized rubber consumption, preventing oozing and reducing material costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The cord achieves improved air impermeability, enhanced corrosion resistance, and simplified manufacturing, resulting in increased endurance and reduced production costs, with the rubber content optimized to prevent oozing and ensure effective penetration.
Implementation Method 1
ensuring the central channel and gaps are filled with rubber
Implementation Method 2
making it possible to improve the fatigue and corrosion-fatigue endurance of the cords
Data Source
AI summary
Metal cord (C-1) having two layers (Ci, Ce) of 3+N construction, rubberized in situ, comprising an inner layer (Ci) formed from three core wires (10) of diameter d1 wound together in a helix with a pitch p1 and an outer layer (Ce) of N wires (11) N varying from 6 to 12, of diameter d2, which are wound together in a helix with a pitch p2 around the inner layer (Ci), wherein said cord has the following characteristics (d1, d2, p1 and p2 are expressed in mm): 0.20<d1<0.50; 0.20<d2<0.50; p1/p2≦1; 5<p1<30; 10<p2<30; the inner layer is sheathed with a diene rubber composition called a “filling rubber” (12) which, for any length of cord of at least 2 cm, is present in the central channel (13) formed by the three core wires and in each of the gaps lying between the three core wires (10) and the N wires (11) of the outer layer (Ce); and the content of filling rubber in the cord is between 5 and 30 mg per g of cord.