M-Shaped Retaining Tab for Vehicle Trim Wall Ejection Prevention

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Solution Overview

Problem

Existing trim structure assemblies for vehicle trim walls are prone to ejection during deformation, such as in the event of an impact or airbag deployment, due to inadequate retention mechanisms, leading to safety concerns and increased costs associated with manual bonding solutions that may not fully prevent ejection.

Innovation Solution

A trim structure assembly featuring a U-shaped frame and M-shaped retaining bracket with a bar and middle part arrangement that tilts the covering element during deformation, ensuring secure attachment by inserting the bar into a hollow V formed between the middle part and the retaining tab, enhancing retention without the need for gluing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the trim structure is simply clipped onto the trim wall opening, then the assembly is easy to manufacture and install, but the retaining strength is insufficient during deformation events

Engineering Contradiction:
Improveassembly simplicityVSAvoidretaining strength
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The retaining element is divided into multiple functional parts: a U-shaped frame for basic retention, and an M-shaped retaining bracket with arms and a central part for enhanced security during deformation. This segmentation allows each part to perform its specific function while maintaining overall assembly simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The M-shaped retaining bracket is designed to be deformable, allowing it to flex during impact events and then return to its original shape. The central part can deform to absorb energy while the arms maintain engagement with the trim wall, providing dynamic retention strength without compromising assembly simplicity.

Inventive Principle:
Principle #15Dynamics

2Strength

If manual bonding is used to attach the covering structure to the trim wall, then the retaining strength during deformation is improved, but the manufacturing cost increases and scrap rate is significant

Engineering Contradiction:
Improveretaining strength during deformationVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The M-shaped retaining bracket is designed to automatically engage and lock the trim structure in place during normal conditions, and to self-adjust during deformation events. The deformable central part automatically absorbs impact energy without requiring external bonding agents or manual intervention, eliminating the need for expensive manual bonding processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The retaining element uses material parameter changes - specifically the elastic properties of the deformable central part - to provide retention strength during deformation. By selecting appropriate materials with suitable elastic characteristics, the system achieves high retaining strength without requiring chemical bonding, reducing manufacturing costs and scrap rates.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the trim wall is made deformable for safety reasons, then the safety performance is improved, but the covering structure may be ejected from the opening during deformation

Engineering Contradiction:
Improvesafety performanceVSAvoidcovering structure retention
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The M-shaped retaining bracket is pre-configured with arms positioned to prevent ejection of the covering structure. Before deformation occurs, the arms are already in place to counteract any potential ejection forces, ensuring that even when the trim wall deforms for safety reasons, the covering structure remains securely retained.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The retaining element incorporates dynamic characteristics through its deformable central part that can flex during impact events. This allows the system to accommodate wall deformation while maintaining coverage structure retention, as the central part absorbs deformation energy while the arms continue to provide stabilizing retention.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3287324B1Assembly of a lining structure with an opening made in a trim wall of a vehicle having an m-shaped retaining tab
Publication Date: 2019.02.27 RENAULT SA
  • EP3287324B1 patent drawingFigure 1~3
  • EP3287324B1 patent drawingFigure 4~5
  • EP3287324B1 patent drawingFigure 6~8

AI summary

The invention relates to an assembly (1) of a cladding structure (2) to a wall opening, the cladding structure comprising a retaining element (6) located on the side of a hidden face of the wall and a cladding element (7) located partly on the side of the visible face and attached to the retaining element (6). The cladding element (7) has, on the side of the hidden face (4b), an internal rim (9) comprising a bar (11). According to the invention, the retaining element has a U-shaped frame (15) and an M-shaped retaining tab (18) attached to the U-shaped frame, located at least partly opposite the bar (11), and arranged so as to retain the cladding element (7) in the event of separation of the cladding element and the retaining element.