Rotatable Connector Flat Cable Winding Interference
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Solution Overview
Problem
Conventional rotatable connectors face difficulties in achieving smooth winding and rewinding operations with three or more flat cables due to interference in driving forces and excessive stress, leading to potential cable buckling and conductor breakage, especially at high temperatures.
Innovation Solution
A rotatable connector design with a stator and rotor having three or more flat cables with reversed winding directions, where the holder features distinct openings with varying widths to manage pressing and attracting forces, ensuring the flat cable passing through the narrower opening has greater bending strength to prevent buckling, and the wider openings reduce frictional resistance interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If three or more flat cables are received in the annular space with reversed winding directions, then the connector can handle multiple circuits, but the driving forces from the cables interfere with each other causing rough operation
Solution Approach 1:
The patent applies local quality by creating distinct opening types (first openings and second openings) with different widths in the holder. The first openings have a width that allows the cable to press the guide wall for driving force, while the second openings have a larger width that reduces frictional resistance. This local differentiation enables different cables to have optimized interaction characteristics with the holder, resolving the interference between driving forces while maintaining multi-circuit capability.
2Force
If the opening width is reduced to increase pressing force, then the holder can rotate more effectively, but the cable frictional resistance increases causing rough operation
Solution Approach 1:
The patent implements local quality by differentiating opening widths: first openings are designed with smaller widths to generate sufficient pressing force for holder rotation, while second openings are designed with larger widths to minimize frictional resistance. This localized optimization allows different cables to experience appropriate force levels without excessive friction, resolving the contradiction between pressing force and operational smoothness.
3Device complexity
If uniform opening widths are used for all cables, then the structure is simpler, but the driving forces interfere causing rough winding operation
Solution Approach 1:
The patent applies local quality by introducing different opening widths (first openings and second openings) in the holder structure. This differentiation creates optimized local interaction zones for different cables, allowing some cables to provide driving force through pressing while others experience reduced friction. This resolves the interference between driving forces and improves winding operation smoothness, accepting increased structural complexity as necessary for functional performance.
4Force
If the flat cable passes through a narrow opening to provide pressing force, then the holder rotates effectively, but the cable may buckle especially at high temperatures
Solution Approach 1:
The patent implements local quality by assigning different opening types to different cables based on their functional roles. Cables requiring pressing force pass through first openings with smaller widths, while cables more prone to buckling or requiring smooth passage use second openings with larger widths. This localized differentiation optimizes both the pressing force generation and cable reliability, preventing buckling especially under high-temperature conditions.
Solution Approach 2:
The patent applies asymmetry by creating non-uniform opening widths in the holder structure. The first openings are deliberately made narrower than the second openings, creating an asymmetric configuration that optimizes the balance between pressing force generation and cable protection. This asymmetric design allows the system to exploit the different mechanical requirements of different cables, improving overall reliability while maintaining effective rotation.
Data Source
AI summary
A rotatable connector includes a stator having an outer cylindrical portion; a rotor having an inner cylindrical portion and rotatably supported by the stator; three or more flat cables received in an annular space defined between the outer cylindrical portion and the inner cylindrical portion, the winding direction of each flat cable being halfway reversed, and opposite ends of each flat cable being fixed to the stator and the rotor, respectively; and a holder rotatably disposed in the annular space and having three or more openings through which the reversed portions of the flat cables pass. A width in the circumferential direction of a first opening is set smaller than a width in the circumferential direction of a second opening different from the first opening, and a bending strength of the flat cable passing through the first opening is set greater than that of the other flat cables.