Control Cable Outer Casing with Embedded Metal Wires
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Solution Overview
Problem
The existing methods for manufacturing outer casings with metal wires buried in resin tubular bodies face challenges such as difficulty in diameter adjustment, high waste material generation, and limitations in using soft thermoplastic elastomers and vinyl chloride resins due to thermal expansion issues and weight concerns, particularly in the context of electric and hybrid vehicles.
Innovation Solution
A two-layered outer casing structure is proposed, comprising an inner tube made of crystalline resin with a melting point of 120°C or higher and an outer tube with metal wires buried in a thermoplastic elastomer or soft vinyl chloride resin layer, allowing for easy adhesion treatment and extrusion molding with improved dimensional accuracy and reduced thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tubular body is formed by tightly winding a flat steel wire around a resin inner tube, then dimensional stability and compression resistance are improved, but weight increases significantly
Solution Approach 1:
The invention uses a composite structure combining resin and metal wires. The outer casing consists of a resin layer with metal wires linearly embedded in the thickness direction, creating a composite material that provides both compression resistance and lightweight properties. This resolves the contradiction by replacing the heavy spiral-wound steel wire structure with a lighter composite structure that maintains necessary mechanical strength.
2Ease of operation
If the outer casing is made soft to improve routing properties, then ease of operation is improved, but thermal expansion increases causing stroke loss
Solution Approach 1:
The composite structure of resin and metal wires allows the outer casing to have soft routing properties while the metal wire reinforcement restricts thermal expansion. The metal wires act as a skeletal framework that maintains dimensional stability during temperature changes while allowing the resin matrix to provide flexibility for routing.
Solution Approach 2:
The metal wires are strategically embedded in the thickness direction of the resin layer, providing localized reinforcement specifically for thermal expansion control while maintaining overall softness for routing. The resin provides flexibility where needed while the metal wires provide stiffness where required for dimensional stability.
3Ease of manufacture
If metal wires are introduced into an extruder die for burying in resin, then ease of manufacture is improved, but diameter adjustment becomes difficult and waste increases
Solution Approach 1:
The metal wires are prepared and positioned in advance before resin extrusion. The wires are fed through the extruder die along with the resin material, and their positions are predetermined in the die design. This preliminary arrangement of metal wires before the extrusion process simplifies the manufacturing process while maintaining dimensional accuracy, as the wires are already in their final positions during molding.
4Ease of operation
If soft thermoplastic elastomer or vinyl chloride resin is used for the outer layer, then routing properties and ease of operation are improved, but thermal expansion control becomes difficult
Solution Approach 1:
The invention uses a composite structure where soft thermoplastic elastomer or vinyl chloride resin is combined with metal wires. The resin provides excellent routing properties and flexibility, while the embedded metal wires provide thermal expansion control. This composite approach allows the use of soft resins without suffering from their inherent thermal expansion issues.
Solution Approach 2:
The metal wires are embedded in the thickness direction of the resin layer, providing localized reinforcement specifically for thermal expansion control while allowing the resin to maintain its softness and flexibility for routing. The resin provides flexibility where needed while the metal wires provide stiffness where required for dimensional stability.
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
This solution results in a lightweight, easy-to-manufacture outer casing with low thermal expansion, enhanced slidability, and improved routing properties, reducing stroke loss and compression issues while maintaining high load efficiency.
Implementation Method 1
an inner tube (12), which includes a crystalline resin
Implementation Method 2
an outer tube (14), which includes an outer resin layer (16) covering an outer periphery of the inner tube (12) and, in the outer resin layer (16), includes a plurality of metal wires (18)
Data Source
AI summary
An outer casing for a control cable 10 has an inner tube 12, which includes a crystalline resin, and an outer tube 14, which includes an outer resin layer 16 covering the outer periphery of the inner tube and, in the outer resin layer, includes plural metal wires 18 buried in parallel with the axial direction of the inner tube and at equal intervals in the circumferential direction of the inner tube.