Bumper Skin Gutter Notches for Thermal Expansion Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The expansion of strongly curved portions of the bumper skin's docking gutter during high heat causes significant curvature variations, leading to potential separation or unclipping of the bumper skirt, compromising the flush clearance and quality of the docking line.

Innovation Solution

Incorporating notches on the distal side wall of the gutter with a V-shape and a thinning angle of 10-30°, spaced at least 5mm apart, to absorb material expansion and maintain curvature stability, preventing localized unclipping and ensuring a consistent touch over the docking line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the gutter has strongly curved portions to meet style constraints, then the aesthetic appearance is improved, but the curvature varies significantly under thermal expansion causing separation or unclipping

Engineering Contradiction:
Improvecurvature of docking lineVSAvoidattachment stability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies local quality by introducing notches specifically at the curved portions of the gutter where thermal expansion causes problems. These notches are placed locally at the distal side wall of the gutter at curved sections, allowing differential movement only where needed while maintaining the overall curved shape for aesthetic purposes. This resolves the contradiction by enabling local adaptation to thermal stress without compromising the global shape quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the gutter by introducing notches that modify the distal side wall profile. These notches create controlled discontinuities in the curvature, allowing the gutter to accommodate thermal expansion through localized parameter changes rather than uniform deformation. This maintains the necessary curved shape while preventing excessive curvature variation that would cause unclipping.

Inventive Principle:
Principle #35Parameter changes

2Shape

If the gutter curvature is increased to meet style constraints, then the aesthetic appearance is improved, but the risk of localized unclipping increases under heat expansion

Engineering Contradiction:
Improvecurvature of docking lineVSAvoidthermal expansion effect
Core Design Contradiction:
ShapeVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of thermal expansion into a beneficial feature by designing notches that allow controlled expansion movement. The notches act as expansion joints that accommodate the thermal growth of the plastic material, transforming what would be a harmful force causing unclipping into a manageable parameter that maintains attachment integrity under varying temperature conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the gutter is made rigid to maintain flush clearance, then the docking quality is improved, but the curvature variation under heat becomes more significant

Engineering Contradiction:
Improveflush clearance qualityVSAvoidcurvature stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent applies segmentation by dividing the continuous distal side wall of the gutter into segments separated by notches at curved portions. This segmentation allows different sections to move independently under thermal expansion, maintaining the overall flush clearance quality while accommodating curvature changes through localized movements at the notched sections.

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

The notches effectively absorb thermal expansion, maintaining the bumper skirt's attachment and preserving the quality of the docking line's contact, preventing unclipping and ensuring a flush fit despite material expansion.

Implementation Method 1

This expansion of the highly curved portions of the bumper skin docking gutter can cause a significant change in their curvature which can lead to a separation of the docking edges of the skirt and the bumper skin

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4313690B1Motor vehicle bumper skin
Publication Date: 2024.11.20 STELLANTIS AUTO SAS
  • EP4313690B1 patent drawingFigure 1~2
  • EP4313690B1 patent drawingFigure 3~4

AI summary

The invention relates to a bumper skin (10) intended to be fastened to a body element (30) by snap-fastening respective edges (14, 33) of the skin and of the element along a docking line (2) having at least one curved section, the edge of the skin comprising an outer portion (15) intended to come flush with a corresponding outer portion (34) of the edge of the element, and an inner portion taking the form of a channel (16) with a U-shaped profile whose opening is oriented towards the outside, the channel comprising a proximal lateral wall (17) connected to the outer portion (15) of the edge of the skin, a distal lateral wall (18) extending substantially parallel to this proximal lateral wall and having at least one notch (21) in each curved section, and a bottom wall (19) connecting the two inner ends of these lateral walls.