In Situ Rubberized Multi-Strand Cord for Tire Belt Corrosion Resistance
Solution Overview
Problem
Multistrand cords used in tire belts for heavy industrial vehicles face challenges with incomplete rubber penetration, leading to corrosion and reduced lifespan due to empty channels within the strands, which also complicates manufacturing with excessive rubber usage and adhesion issues.
Innovation Solution
A novel multistrand cord with a K×(L+M) construction where each elementary strand is rubberized in situ, ensuring filling rubber is present in capillaries and the central channel, using a specific twisting and rubberizing process to control the amount of rubber and prevent overspill, resulting in improved air impermeability and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multistrand cords are used with empty capillaries and channels, then manufacturing is simpler, but corrosion resistance and air impermeability deteriorate
Solution Approach 1:
The patent applies preliminary action by injecting rubber composition into the elementary strands during the twisting process, before the strands are fully assembled into the multistrand cord. This preliminary rubberization ensures that capillaries and channels are filled with rubber before final cord assembly, preventing corrosion pathways without requiring complex post-manufacturing treatments.
Solution Approach 2:
The patent implements self-service through the in situ rubberization process where the rubber composition is injected directly into the elementary strands and distributes itself through capillaries and channels via capillary action. The rubber system serves itself to fill internal voids without external intervention, achieving complete penetration and elimination of corrosion pathways automatically.
2Reliability
If excessive rubber is used to fill all capillaries and channels, then air impermeability improves, but manufacturing complexity and rubber overspill increase
Solution Approach 1:
The patent applies parameter changes by carefully controlling the rubber composition formulation, injection pressure, and injection timing during the twisting process. By optimizing these parameters, the system achieves complete capillary filling without overspill, transforming the challenge of excessive rubber usage into a controlled process that delivers precise rubber placement.
Solution Approach 2:
The patent implements feedback through monitoring the rubber injection process during twisting, adjusting injection parameters based on real-time observations of rubber distribution. This feedback mechanism ensures that rubber is injected at the optimal rate and pressure to fill all capillaries and channels completely without causing overspill or manufacturing defects.
3Reliability
If rubber composition is injected during twisting, then capillary filling is achieved, but adhesion issues and manufacturing complexity arise
Solution Approach 1:
The patent applies merging by combining the rubber injection process with the twisting operation into a single integrated manufacturing step. The rubber composition is injected into elementary strands during the twisting process itself, merging two operations that were traditionally separate. This integration achieves complete capillary filling while maintaining manufacturing efficiency and avoiding the adhesion issues associated with sequential processing.
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 solution ensures the multistrand cord is airtight, enhancing fatigue-corrosion resistance and manufacturing efficiency by maintaining the rubber within the strand, thus improving the endurance and performance of tire belts.
Implementation Method 1
ensuring filling rubber is present in capillaries and the central channel
Data Source
AI summary
Metal cord of K×(L+M) construction. K elementary strands assembled in a helix, with pitch PK, each having a cord with L wire inner layer of diameter d1, and M wire outer layer of diameter d2, in a helix with pitch p2 around the inner layer; with (in mm): 0.10<d1<0.50; 0.10<d2<0.50; 3<p2<10; inner layer is sheathed with filling rubber; over a K times PK length of the elementary strand, filling rubber is in each of the capillaries delimited by the L wires of the inner layer and the M wires of the outer layer, and also, when L is equal to 3 or 4, in the central channel delimited by the L wires of the inner layer. The amount of filling rubber in said elementary strand is 5 to 40 mg per g of elementary strand.