In-situ Rubberized 3+N Cable for Tire Carcass Corrosion Resistance
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Solution Overview
Problem
Current two-layer metal cables of 3+N construction used in tire carcass reinforcements face issues with incomplete rubber penetration, leading to empty channels that can cause corrosion and reduce the lifespan of tires, due to the presence of a central capillary in the core wires which acts as a conduit for corrosive agents, and existing gumming processes are inefficient and industrially challenging.
Innovation Solution
A 3+N layer metal cable with a specific structure and manufacturing process where the internal layer of three core wires is sheathed with diene rubber, ensuring the filling gum is present in the central channel and interstices, achieving a controlled filling rate of 5-35 mg/g, and the cable is designed to be impervious to corrosive fluids, eliminating the wicking effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional 3+N cables are used with a central core of three wires, then the cable structure is simple and manufacturing is easier, but a central capillary channel remains empty after rubber impregnation, allowing corrosive agents to penetrate and causing fatigue-fretting-corrosion
Solution Approach 1:
The patent applies preliminary action by performing rubber impregnation on the internal layer of three core wires before assembling the external layer. This preliminary rubber filling of the central capillary channel prevents corrosive agents from penetrating through the cable core, thereby resolving the contradiction between manufacturing simplicity and corrosion resistance.
2Reliability
If individual wire sheathing is performed upstream of the assembly point, then the central capillary can be filled with rubber, but the process becomes complex and industrially challenging with multiple extrusion heads required
Solution Approach 1:
The patent inverts the conventional sequence by performing rubber impregnation downstream of the assembly point rather than upstream. This reversal allows the central capillary to be filled with rubber after the wires are assembled, eliminating the need for multiple extrusion heads and simplifying the manufacturing process while maintaining complete impregnation.
3Reliability
If rubber impregnation is performed to fill all interstices, then corrosion resistance is improved, but manufacturing time and process complexity increase
Solution Approach 1:
The patent segments the rubber impregnation process into two distinct stages: first impregnating the internal layer of three core wires to fill the central capillary, then impregnating the external layer to fill the interstices between wires. This segmentation achieves complete corrosion protection while optimizing manufacturing time by addressing different impregnation requirements in separate, efficient steps.
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 cable achieves improved resistance to fatigue-fretting-corrosion, enhanced rubber penetration, reduced manufacturing complexity, and increased longevity of tire carcass reinforcements by ensuring complete impregnation and airtightness, thereby extending the lifespan of tires.
Implementation Method 1
the filling gum fills the central capillary formed by the three core wires by spreading them slightly, while completely covering the internal layer... It also fills, at least in part, each of the interstices formed either by a core wire and the two external wires
Implementation Method 2
which remains empty after external impregnation with rubber and therefore conducive, through a sort of 'wick' effect, to the propagation of corrosive environments such as water
Data Source
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AI summary
Two-layer (Ci, Ce) metal cable (C-1) of 3+N construction, rubberized in situ, comprising an inner layer (Ci) consisting of three core wires (10) of diameter di wound together helically with a pitch pi and an outer layer (Ce) of N wires (11), N varying from 6 to 12, of diameter d2 wound together helically with a pitch p2 around the inner layer (Ci), said cable being characterized in that it has the following features (d1, d2, p1, p2 being in mm): 0.08 1 2 1 / p2 1 2 < 30; the inner layer is sheathed in a diene rubber composition termed the "filler rubber" (12) which, for any 2 cm or greater length of cable, is present in the central channel (13) formed by the three core wires and in each of the interstices between the three core wires (10) and the N wires (11) of the outer layer (Ce); the filler rubber ratio in the cable being between 5 and 35 mg per g of cable. Multistrand cable comprising at least one two-layer cable according to the invention, intended particularly for tyres for industrial vehicles of the civil engineering type.