Multi-Core Cable Inclusion Sizing for Uniform Sheath Extrusion
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Solution Overview
Problem
The uniformity of the sheath thickness in multi-core cables is compromised due to deformation and uneven resin distribution, leading to wrinkles and reduced abrasion resistance, when the inclusion's diameter is reduced to apply tension for stabilizing the twist pitch of electric wires.
Innovation Solution
Manufacture the multi-core cable by preparing an inclusion with a diameter larger than the predetermined size, applying tension to reduce it to the desired diameter, and twisting electric wires around it to maintain a circular cross-sectional shape, followed by extrusion-molding a sheath onto the inner wire portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If tension is applied to the inclusion to stabilize the twist pitch of electric wires, then the tensile strength is improved, but the diameter of the inclusion is reduced causing deformation of the circular structure and non-uniform sheath thickness
Solution Approach 1:
The invention applies preliminary action by pre-forming the inclusion with a larger diameter before the extrusion process. This preliminary sizing compensates for the diameter reduction that occurs when tension is applied during twisting, ensuring the inclusion maintains sufficient diameter throughout the manufacturing process to preserve circular structure and sheath uniformity.
Solution Approach 2:
The invention changes the parameter of inclusion diameter from a fixed small value to a variable that is initially larger and then controlled to reduce to the target diameter during the process. This parameter change allows the inclusion to provide adequate structural support during twisting while achieving the desired final dimensions.
2Stability of the object's composition
If tension is applied to the inclusion to stabilize the twist pitch, then the twist pitch stability is improved, but the circular cross-sectional structure is deformed
Solution Approach 1:
The inclusion is pre-formed with a larger diameter to provide sufficient structural rigidity before twisting begins. This preliminary structural preparation ensures the inclusion can withstand the twisting process while maintaining its circular cross-sectional shape, thereby stabilizing the twist pitch of electric wires without deformation.
3Strength
If the inclusion diameter is reduced to apply tension, then the tensile strength is improved, but wrinkles appear in the external appearance and abrasion resistance decreases
Solution Approach 1:
The inclusion is pre-formed with a larger diameter to maintain sufficient structural integrity during the extrusion process. This prevents wrinkles in the external appearance and ensures uniform sheath thickness, thereby maintaining abrasion resistance while still achieving the required tensile strength through controlled tension application.
4Strength
If the inclusion diameter is reduced, then the tensile strength is improved, but unnecessary resin increases in portions where sheath thickness is large
Solution Approach 1:
The inclusion is pre-formed with a larger diameter to maintain proper geometry during extrusion, ensuring uniform sheath thickness distribution. This eliminates unnecessary resin accumulation in areas where sheath thickness would otherwise be excessively large, optimizing material usage while maintaining tensile strength.
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
Improves the uniformity of the sheath thickness and prevents wrinkles, enhancing the abrasion resistance and reducing resin usage, thereby optimizing the manufacturing process.
Implementation Method 1
applying tension to reduce it to the desired diameter
Implementation Method 2
the diameter is reduced to the predetermined diameter
Implementation Method 3
twisting electric wires around it to maintain a circular cross-sectional shape
Implementation Method 4
followed by extrusion-molding a sheath onto the inner wire portion
Data Source
AI summary
A method for manufacturing a multi-core cable including an inclusion, a plurality of electric wires twisted around the inclusion in a state that tension is applied to the inclusion, a shield portion provided around the electric wires, and a sheath is provided. The method includes a preparation step of preparing the inclusion having a diameter exceeding a predetermined diameter on assumption that tension is applied to the inclusion and the diameter is reduced to the predetermined diameter, a twisting step of twisting the electric wires while applying tension to the inclusion using the inclusion prepared in the preparation step as the central member, an inner wire manufacturing step of manufacturing an inner wire portion by providing the shield portion around the electric wires twisted by the twisting step, and an extrusion step of extrusion-molding a sheath to the inner wire portion manufactured in the inner wire manufacturing step.