Rotary Connector Flat Cable Winding Mechanism

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Solution Overview

Problem

Existing rotary connectors face difficulties in smoothly winding and rewinding multiple flat cables due to interference in driving forces applied by reversed portions through varying opening widths, leading to buckling and conductor breakage, especially under high temperatures.

Innovation Solution

A rotary connector design where one flat cable with higher bending strength serves as the driving side, passing through a narrower opening to apply a pushing force, while other cables with lower bending strength are driven side cables passing through wider openings, reducing bending stress and preventing buckling, and all cables are led from a common lead-out portion to minimize curvature and stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If three or more flat cables are used in a rotary connector, then the number of circuits is increased, but the cables interfere with each other during winding/rewinding causing buckling and conductor breakage

Engineering Contradiction:
Improvenumber of circuitsVSAvoidcable integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the group of flat cables into two segments: a driving side flat cable that applies pushing force to the holder, and driven side flat cables that are passively wound. This segmentation allows the driving cable to have higher bending strength for reliable force application, while driven cables can have lower bending strength, resolving the conflict between supporting multiple circuits and preventing cable damage during operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different quality requirements to different cables based on their functional roles. The driving side flat cable is designed with higher bending strength to withstand the mechanical stress of driving the holder, while driven side flat cables have lower bending strength as they only need to be passively wound. This local differentiation of cable properties allows multiple circuits to coexist without mutual interference causing buckling or breakage.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If opening widths are varied to accommodate multiple cables, then cable routing is improved, but driving force interference occurs making smooth winding/rewinding difficult

Engineering Contradiction:
Improvecable routingVSAvoiddriving force control
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the driving function from the group of flat cables and assigns it to a single driving side flat cable. This driving cable passes through a specifically designed opening (first opening) with controlled width that allows it to apply pushing force to the holder without interference from other cables. The driven side flat cables pass through separate openings (second openings) and are purely passive, eliminating driving force interference while maintaining ease of cable routing.

Inventive Principle:
Principle #2Taking out (Extraction)

3Force

If driving side flat cable passes through narrow opening, then pushing force is effectively applied, but bending stress increases risking cable failure

Engineering Contradiction:
Improvepushing force to holderVSAvoidbending strength requirement
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The patent performs preliminary action by selecting and positioning the driving side flat cable with sufficiently high bending strength before operation begins. The cable is pre-configured to pass through the narrow first opening and apply effective pushing force to the holder. By ensuring the driving cable has the necessary bending strength in advance, the system achieves effective force application without risking cable failure during operation.

Inventive Principle:
Principle #10Preliminary action

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 design enables smooth and stable winding/rewinding of multiple flat cables, even under high-temperature conditions, by reducing bending stress and preventing buckling, thus extending the life of the driving side flat cable and ensuring reliable operation.

Implementation Method 1

the driving side flat cable that applies a pushing force to the holder in the rotational direction

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2078640B1Rotary connector
Publication Date: 2011.03.30 ALPS ALPINE CO LTD
  • EP2078640B1 patent drawingFigure 1
  • EP2078640B1 patent drawingFigure 2
  • EP2078640B1 patent drawingFigure 3

AI summary

A rotary connector includes a stator (1) that includes an outer cylindrical part, a rotor (2) that includes an inner cylindrical part (8b) and is rotatably supported by the stator, three or more flat cables (3, 4) that are received in an annular space (10) formed between the outer and inner cylindrical parts while being reversely wound on the way, and a holder (5) that is rotatably disposed in the annular space (10) and includes three or more openings through which reversed portions (3a, 4a) of the flat cables (3, 4) individually pass. The width of one opening in a circumferential direction is set to be smaller than that of each of the other openings in the circumferential direction. The holder (5) is driven by a pushing force from the flat cable that passes through the narrow opening. The bending strength of the driving side flat cable (3) is set to be higher than that of each of the other flat cables.