Twisted Cable Smooth Surface via Layer Segmentation
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Solution Overview
Problem
Conventional metal cables used in brake assemblies suffer from high friction, elongation, and mechanical property damage due to manufacturing issues and surface deformation, leading to poor operational performance.
Innovation Solution
A twisted metal cable design featuring a central wire surrounded by concentric layers of wires classified by cross-sectional area, with specific ratios and arrangements to minimize friction and elongation, while maintaining structural integrity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If outer wires are pressed and deformed to smoothen the outer surface, then friction is reduced, but manufacturing complexity increases and mechanical properties deteriorate
Solution Approach 1:
The cable structure is segmented into multiple layers (inner layer with 6 second wires, middle layer with first and third wires, outer layer with fourth wires) with different wire sizes and functions. This segmentation allows the outer layer to provide smooth surface without requiring severe deformation of individual wires, thus reducing manufacturing complexity while maintaining low friction.
Solution Approach 2:
Different layers are assigned different wire diameters and properties: inner layer uses smaller second wires for compactness, middle layer uses alternating first and third wires for structural balance, and outer layer uses larger fourth wires with specific curvature ratios (outer surface curvature < inner surface curvature) to naturally provide smooth surface. This local differentiation eliminates the need for severe post-manufacturing deformation.
2Shape
If outer wires are severely deformed to remove lines and veins, then surface smoothness is improved, but mechanical properties such as elongation coefficient are damaged
Solution Approach 1:
The smooth surface is achieved through the preliminary design of the outer layer wire geometry rather than post-manufacturing deformation. The fourth wires in the outer layer are designed with specific curvature characteristics (outer surface curvature smaller than inner surface curvature) that naturally create a smooth external surface, eliminating the need for severe pressing and deforming operations that would damage mechanical properties.
Solution Approach 2:
Instead of changing the physical state of wires through severe deformation, the invention changes geometric parameters of the outer layer wires. The fourth wires are designed with specific curvature ratios and are arranged in a configuration where their outer surfaces collectively form a smooth cable surface, maintaining wire integrity and mechanical properties while achieving the desired surface quality.
3Shape
If elliptical wires are used to smoothen outer surface, then veins are reduced, but interval vacant space increases and effective cross section area decreases
Solution Approach 1:
The invention uses curved wire configurations rather than elliptical cross-sections. The fourth wires in the outer layer are designed with specific curvature characteristics where the outer surface curvature is smaller than the inner surface curvature. This curvature design allows wires to pack more efficiently with reduced vacant space while still providing a smooth outer surface, unlike elliptical wires which create larger gaps.
Data Source
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AI summary
A multi-layer twisted strand or cable (1) comprising one central elongate element (11) surrounded by three layers of elongate elements, namely an inner layer, a middle layer and an outer layer. Said elongate elements are wires or strands of twisted wires. The surround elongate elements have several different sizes of area of transversal cross section thereof. The middle layer comprises elongate elements (12,14) of different size of area within the middle layer and the sizes of area of the elongate elements between the layers are different. The outer surround elongate elements (15) having the largest size of area. The outer surround elongate elements have a smoothened outer surface (152), so that the twisted strand or cable (1) has a smooth and satiny outer surface (152). All surround elongate elements (13,12,14,15) having the same lay direction and the same pitch. Elongation when stretch force is exerted on the twisted strand or cable and friction and abrasion caused by pulling the twisted strand or cable is reduced.