Stepped Cable Feedthrough Assembly Sealing

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Solution Overview

Problem

Existing cable bushing arrangements for electromotive linear actuators face difficulties in securely pulling cables out from the housing interior, particularly in ensuring a sealed passage and easy assembly.

Innovation Solution

A stepped opening design with a small step near the housing interior and a larger step outwardly, featuring a connecting element with an axial pin and a cable grommet that provides elastic radial contact, allowing easy cable guidance and secure sealing, and enabling easy assembly and leak detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional cable bushing arrangement is used, then the cable passage is sealed, but it is difficult to pull the cable out tightly from the housing interior

Engineering Contradiction:
Improvecable removalVSAvoidsealing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The opening is segmented into two distinct steps: a first step providing a first opening area and a second step providing a second opening area. This segmentation allows the cable grommet to be positioned at the first step while the connecting element is secured at the second step, enabling separate optimization of cable removal ease and sealing reliability at each location.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A cable grommet is introduced as an intermediary component between the cable and the housing interior. The cable grommet provides the sealing function at the first opening area, allowing easy cable removal, while the connecting element provides the secure mounting at the second opening area. This intermediary component resolves the contradiction by separating the sealing function from the mounting function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sealing point is located deep inside the housing, then sealing is effective, but it is difficult to detect leaks from the outside

Engineering Contradiction:
ImprovesealingVSAvoidleak detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The cable grommet acts as an intermediary sealing element positioned at the first step which is more accessible than deep internal sealing points. While maintaining effective sealing, its position allows for easier inspection and leak detection from the outside compared to sealing points located deep within the housing interior.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stepped opening structure creates a dimensional hierarchy with the first step closer to the exterior and the second step deeper inside. This dimensional arrangement allows the sealing function to be distributed across different depths, with the cable grommet at the first step providing an externally accessible sealing point for easier leak detection while the second step provides structural support.

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

3Adaptability or versatility

If different end closures require different cable bushing arrangements, then each application is optimized, but manufacturing costs increase

Engineering Contradiction:
Improveapplication-specific optimizationVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The connecting element is designed as a universal component that can be used across different end closure types. The standardized connecting element with its specific geometry can be integrated into various end closure designs, eliminating the need for custom cable bushing arrangements for each application and thereby reducing manufacturing costs while maintaining application-specific optimization.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cable bushing arrangement is segmented into modular components: the cable grommet for sealing and the connecting element for mounting. This modularity allows the connecting element to be a standardized universal part that can be adapted to different end closures, while the cable grommet can be selected based on specific sealing requirements, achieving both universality and application-specific optimization.

Inventive Principle:
Principle #1Segmentation

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

Facilitates a simple, sealed cable lead-out with enhanced sealing efficacy and cost-effective use of identical parts across various linear adjusting devices, reducing assembly complexity and complaint costs.

Implementation Method 1

with a cable grommet through which the cable that can be guided through the through-opening of the connecting element can be guided to the outside and which encloses the holding area with its one end and with elastic pretension radially circumferentially so is in contact with the radially circumferential outer surface of the holding area and also with the radially circumferential inner surface of the large step of the step opening

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3525305B1Cable feedthrough assembly
Publication Date: 2021.04.07 STABILUS GMBH
  • EP3525305B1 patent drawingFigure 1

AI summary

The invention relates to a cable feedthrough arrangement for the sealed passage of a cable 20 from the outside through an insertion opening in an end closure 1 of an electromechanical linear actuator into a housing interior 5 of the linear actuator.