Bowden Cable Seal Structure for Humidity and Vibration Loads

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Solution Overview

Problem

Existing Bowden cables in motor vehicles face challenges in effectively sealing against extreme environmental conditions and mechanical loads, such as humidity and vibrations, which can compromise their functionality, especially when used in wet areas like vehicle doors or tailgates.

Innovation Solution

A Bowden cable design featuring a shell and core with a seal comprising a sleeve slid over the core and a concentric spiral spring, where the spring has a conical extension that embraces the sleeve, providing a flexible and elastic seal that maintains efficiency even under high mechanical loads and extreme conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional seal design is used for the Bowden cable core, then the structure is simple, but the sealing effectiveness against extreme humidity and mechanical loads deteriorates

Engineering Contradiction:
Improvesealing effectivenessVSAvoidseal structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The seal comprises a sleeve (4) that is slid over the core (3) and a spring (5) that is inserted into the sleeve, creating a nested structure where the spring is contained within the sleeve. This nested arrangement allows the seal to maintain effectiveness under mechanical loads while keeping the overall structure compact and manageable.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The spring (5) with conical extension (5.1) is designed to embrace the sleeve (4) and provide elastic cushioning before extreme mechanical loads or humidity exposure can compromise the sealing. The spring acts as a pre-positioned protective element that maintains seal integrity under stress.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the Bowden cable is placed in wet areas for flexible positioning, then adaptability improves, but exposure to environmental influences like humidity increases

Engineering Contradiction:
Improvepositioning flexibilityVSAvoidhumidity exposure
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sleeve (4) acts as a flexible protective shell that can be positioned in various locations including wet areas, while the spring (5) with conical extension provides the necessary flexibility to accommodate positioning variations. This flexible shell structure allows the Bowden cable to adapt to different installations while maintaining sealing effectiveness against humidity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If a rigid seal structure is used, then manufacturing precision is easier to achieve, but the seal effectiveness under mechanical loads like vibrations deteriorates

Engineering Contradiction:
Improveseal constructionVSAvoidseal performance under load
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The spring (5) with conical extension (5.1) embraces the sleeve (4) to provide a dynamic, elastic sealing mechanism that can adapt to mechanical loads and vibrations during vehicle operation. This dynamic structure maintains reliable sealing under varying conditions while remaining manufacturable through standard spring and sleeve fabrication processes.

Inventive Principle:
Principle #15Dynamics

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

The design ensures a highly effective seal that remains functional under mechanical loads and environmental exposures, ensuring the Bowden cable's reliability in sealing the sliding range of the core, even in extreme conditions and during vehicle operation.

Implementation Method 1

a spring which actuates the sleeve, the spring being designed as concentric spiral spring having a conical extension

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3303860B1Bowden cable used as actuator for a functional unit in a motor vehicle
Publication Date: 2021.03.24 KIEKERT AG
  • EP3303860B1 patent drawingFigure 1
  • EP3303860B1 patent drawingFigure 1a~1c
  • EP3303860B1 patent drawingFigure 2

AI summary

The invention relates to a Bowden cable (1) consisting of a shell (2) and a core (3) as well as of a seal (4, 5) for the core (3), preferably built as actuator for a functional device (10) in a motor vehicle (16), with the seal being built by a sleeve (4) slid over the core (3), and a spring (5) actuating the sleeve (4). The invention also relates to a latch (10) with such Bowden cable (1) for a motor vehicle (16). The Bowden cable (1) has a highly effective seal against environmental influences, also under usual loads as they occur in motor vehicles such as impacts or vibrations.