Inner Cable Stranding for Window Regulator Durability
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Solution Overview
Problem
Conventional inner cables used in non-rotating guiding devices suffer from low durability due to secondary bending and abnormal noise generation caused by uneven stranding and friction, which affects their performance in applications like window regulators.
Innovation Solution
An inner cable with a complex stranded construction featuring a core strand and side strands, where the stranding length is 9 to 18-fold against the outer diameter, and a tightening percentage of 4 to 11% and pre-forming percentage of 65 to 90%, along with a specific stranding angle, to minimize secondary bending and friction, thereby enhancing durability and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional inner cable with loose strand is used, then ease of manufacture is improved, but durability of bending fatigue deteriorates due to secondary bending and local bending
Solution Approach 1:
The patent applies parameter changes by precisely controlling the stranding length (9-18 times the outer diameter) and tightening percentage (4-11%) of the inner cable. These parameter adjustments optimize the balance between manufacturing ease and bending fatigue durability, preventing secondary bending while maintaining manufacturability.
Solution Approach 2:
The patent introduces dynamic characteristics by specifying that the outermost lay strand should be an ordinary lay (not fixed lay), allowing the cable structure to adapt dynamically to bending stresses. This dynamic configuration reduces secondary bending effects while maintaining ease of manufacture.
2Reliability
If tightening percentage is increased to prevent deformation, then durability of bending fatigue is improved, but manufacturing complexity increases and wire breaking risk increases
Solution Approach 1:
The patent optimizes the tightening percentage parameter within a specific range (4-11%) to achieve the desired durability without excessive manufacturing complexity. This parameter optimization prevents wire breaking while maintaining bending fatigue resistance.
Solution Approach 2:
The patent applies partial tightening (4-11% range) rather than excessive tightening, achieving sufficient deformation prevention and durability improvement without the negative effects of over-tightening such as wire breaking and manufacturing complexity.
3Reliability
If pre-forming percentage is increased to prevent secondary bending, then durability is improved, but friction and noise generation increase
Solution Approach 1:
The patent controls the pre-forming percentage within the range of 65-90% to achieve optimal balance. This parameter control prevents secondary bending and improves durability while minimizing friction and noise generation during cable operation.
Solution Approach 2:
The patent applies partial pre-forming (65-90% range) rather than complete pre-forming, achieving sufficient secondary bending prevention and durability improvement while avoiding excessive friction and noise that would result from over-pre-forming.
4Ease of operation
If stranding length is decreased for compact construction, then ease of operation is improved, but rotation resistance deteriorates
Solution Approach 1:
The patent optimizes the stranding length parameter to be 9-18 times the outer diameter, achieving an optimal balance between compact construction for ease of operation and sufficient rotation resistance for stability in non-rotating guiding devices.
Data Source
AI summary
A cable for operation with a complex stranded construction may include a core strand stranded with a plurality of element wires and a plurality of side strands on which a plurality of element wires are respectively stranded are stranded. A tightening percentage may be 4 to 11%. The pre-forming percentage may be 65 to 90%. The stranding length of the inner cable for operation is 9 to 18-fold against the outer diameter of the inner cable for operation and an angle of the element wires composing the side strand appearing at the outermost lay against an axis line of the inner cable is −3 degrees to 3 degrees.