Rotatable Connector Flat Cable Bent Portion

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Solution Overview

Problem

Rotatable connector devices for automobiles generate unusual sounds due to contact between the fixed-side and rotatable-side members, and existing solutions complicate the structure or expose the internal components, leading to poor appearance and potential foreign object invasion.

Innovation Solution

A bent portion in the flat cable shifts the terminal conductor connection section in the width direction, lowering its position and preventing contact, while maintaining a simple structure and avoiding the need for cut-offs in the column cover.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the fixed-side cable end accommodation section is positioned high to accommodate the terminal conductor connection section, then the terminal conductor connection is achieved, but the rotatable-side member contacts the fixed-side cable end accommodation section during rotation generating unusual sound

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidunusual sound during rotation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a bent portion in the flat cable that shifts the terminal conductor connection section in the width direction (lateral dimension) rather than only in the thickness direction. This dimensional change allows the connection section to be positioned laterally offset from the cable path, enabling the fixed-side cable end accommodation section to be lowered without compromising electrical connection, thereby preventing contact with the rotatable-side member during rotation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent segments the cable routing into distinct sections: a first section extending from the rotatable-side member, a bent portion shifting laterally, and a second section extending to the fixed-side member. This segmentation allows independent optimization of each section's path, enabling the terminal conductor connection section to be positioned in a location that avoids rotation-induced contact while maintaining electrical connectivity.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If terminal conductors are bent in the width direction of the flat cable to avoid contact, then contact between members is prevented, but the structure of conductor routing is complicated and cost increases

Engineering Contradiction:
Improvecontact preventionVSAvoidconductor routing structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

Instead of bending terminal conductors in the width direction which complicates routing, the patent introduces a bent portion in the flat cable itself that shifts the entire cable assembly laterally. This approach prevents contact by changing the cable's lateral position rather than individual conductor paths, maintaining simple conductor routing while achieving contact prevention.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Object-generated harmful factors

If the fixed-side cable end accommodation section is lowered to prevent contact, then unusual sound is prevented, but the terminal conductor connection section positioning becomes difficult

Engineering Contradiction:
Improveunusual sound preventionVSAvoidterminal conductor connection positioning
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent incorporates a bent portion in the flat cable during the cable manufacturing process, which preliminarily positions the terminal conductor connection section in a lateral offset location. This preliminary action ensures that when the fixed-side cable end accommodation section is lowered, the terminal connection section is already positioned to avoid contact with the rotatable-side member, simplifying the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

4Object-generated harmful factors

If a cut-off portion is made in the column cover to avoid contact, then contact between members is prevented, but the appearance deteriorates and foreign objects can enter

Engineering Contradiction:
Improvecontact preventionVSAvoidforeign object intrusion
Core Design Contradiction:
Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the potential contact problem by laterally shifting the terminal conductor connection section using the bent portion in the flat cable. This extraction allows the fixed-side cable end accommodation section to be positioned lower without requiring any modifications to the column cover, thereby maintaining the cover's integrity and preventing foreign object intrusion while still preventing contact between members.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2555343B1Rotatable connector device
Publication Date: 2019.07.17 FURUKAWA ELECTRIC CO LTD
  • EP2555343B1 patent drawingFigure 1
  • EP2555343B1 patent drawingFigure 2
  • EP2555343B1 patent drawingFigure 3

AI summary

In a rotatable connector device, generation of an unusual sound, which would otherwise be caused by contact during the rotation of a rotator, is prevented without, for example, complicating the structure of terminal conductors; and also another advantage is provided. A rotatable connector device 21 includes a stator 31 and a rotator 41; and also has a fixed-side cable end accommodation section 34, projecting from an outer circumferential surface of the stator 31 in a tangential direction thereof, for accommodating and holding a mold section 16 provided at a fixed-side end of a flat cable 11 accommodated in the rotatable connector device 21. In a portion of the flat cable 11 on the side of the fixed-side mold section 16, a bent portion 12 which is folded to be shortened so as to shift a fixed-side end 11a in a width direction of the flat cable 11, resulting in the flat cable 11 being shortened in a longitudinal direction thereof, is formed by a trough line 12a and a ridge line 12b parallel to each other and extending in a direction crossing the longitudinal direction of the flat cable 11.