Steering Column Rotary Connector Liquid Barrier Design

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Solution Overview

Problem

Existing steering column structures fail to prevent liquids from reaching the rotary connector, leading to 'green rust' and increased electrical resistance, which can cause malfunctions in air bag systems.

Innovation Solution

A steering column structure with a dam portion above the rotary connector, extending along its periphery, integrated into the steering column and lower covers, prevents liquids from entering the rotary connector by creating a barrier and directing them away from critical areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a gap is defined between the steering column cover and the steering lower cover to allow rotational movement, then the steering wheel can be turned freely, but liquid can enter the gap and reach the rotary connector causing green rust and electrical resistance increase

Engineering Contradiction:
Improvesteering wheel rotationVSAvoidelectrical connection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A dam portion is introduced as an intermediary element between the gap and the rotary connector. This dam portion acts as a barrier that prevents liquid from the gap from reaching the rotary connector, while not interfering with the normal rotational operation of the steering wheel. The dam portion is specifically positioned to block liquid flow paths to the connector portions and FFC insertion hole.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dam portion is strategically positioned only in specific locations where liquid accumulation and flow toward the rotary connector occurs. Rather than sealing the entire gap (which would prevent rotation), the dam portion is placed locally at critical areas such as the rotary case post portion and around the FFC insertion hole, providing protection only where needed while maintaining overall operational freedom.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the rotary case post portion is provided with a fitting groove and lock hole for cable connection, then cable assembly is facilitated, but liquid reaching these grooves and holes accumulates and causes green rust on the connecting portions

Engineering Contradiction:
Improvecable assembly easeVSAvoidliquid accumulation and green rust
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The dam portion serves as a protective intermediary that blocks liquid from reaching the fitting groove and lock hole in the rotary case post portion. By positioning the dam portion above these features, liquid flow is intercepted before it can enter the cable connection areas, preventing accumulation and subsequent green rust formation while maintaining the cable assembly structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The dam portion is positioned in advance to prevent liquid from reaching the vulnerable cable connection areas. This preliminary protective barrier stops liquid accumulation before it can cause harm to the fitting groove and lock hole, proactively preventing the green rust problem rather than addressing it after occurrence.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If a gap is open vertically downward to prevent liquid entry according to prior art, then liquid is prevented from entering the rotary connector, but this does not address the specific structure of steering column covers and the liquid flow paths in this application

Engineering Contradiction:
Improveliquid preventionVSAvoidsteering cover structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of implementing a comprehensive sealing structure throughout the steering column cover, the dam portion is applied locally only where liquid flow paths converge toward the rotary connector. This selective approach provides effective liquid prevention at critical areas (rotary case post portion, FFC insertion hole) without adding unnecessary complexity to the overall steering cover structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The dam portion acts as a simple intermediary barrier that effectively blocks liquid flow paths in the steering column cover structure. By positioning this single structural element appropriately, the patent achieves liquid prevention without requiring complex multi-component sealing systems, thus maintaining structural simplicity while improving reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3421325B1Steering column structure
Publication Date: 2021.03.31 FURUKAWA ELECTRIC CO LTD
  • EP3421325B1 patent drawingFigure 1
  • EP3421325B1 patent drawingFigure 2
  • EP3421325B1 patent drawingFigure 3

AI summary

Provided is a steering column structure capable of preventing liquid from reaching a rotary connector. A steering column structure (1) includes a rotary connector (10), a steering column cover (20), and a steering lower cover (30) attached with a gap (4) defined between the steering lower cover (30) and the steering column cover (20). The steering column cover (20) includes a first side wall portion (23) defining the gap (4), and a first insertion hole (24) that is disposed in the first side wall portion (23) and into which the rotary connector (10) is inserted. The steering lower cover (30) includes a second side wall portion (34) facing the first side wall portion (23) and defining the gap (4) together with the first side wall portion (23), and a second insertion hole (35) that is disposed in the second side wall portion (34) and into which the rotary connector (10) is inserted. The first side wall portion (23) includes a first dam portion (25) disposed in a position corresponding to the rotary connector (10) above the rotary connector.