Sliding Element Groove for Thermal Expansion Compensation

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Solution Overview

Problem

The existing fastening devices for vehicle body parts, particularly those made of plastics, face issues with irreversible deformation due to thermal expansion, leading to aesthetic and functional problems, and the sliding elements' movement is impeded by drying liquids in gaps, causing rattling and high rework costs.

Innovation Solution

A component with a longitudinal groove and channels for liquid drainage is designed, allowing the sliding element to move freely and compensate for thermal expansion, while the surface treatment reduces wettability to enhance liquid drainage, preventing sticking and movement impediment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a narrow gap is selected between the sliding element and the body part to prevent rattling and ensure low joint tolerance, then the sliding element's movement is impeded by drying liquids in the gap, causing sticking and movement impediment

Engineering Contradiction:
Improvejoint toleranceVSAvoidsliding movement reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The gap between the sliding element and body part is segmented into multiple regions by introducing channels. These channels divide the continuous gap into separate zones, allowing liquid to be drained from specific areas while maintaining the overall narrow gap structure for low joint tolerance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Channels are introduced as intermediary structures within the gap region. These channels act as mediators that facilitate liquid drainage while preserving the narrow gap dimensions needed for low joint tolerance and preventing rattling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sliding element is tightly fitted to the body part to prevent rattling, then liquid accumulates in the gap during painting, causing the sliding element to stick and deform permanently

Engineering Contradiction:
Improveanti-rattling performanceVSAvoidliquid accumulation and sticking
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The harmful liquid is extracted from the gap between the sliding element and body part through the introduction of channels. These channels provide a pathway for liquid to be removed from the critical interface area, preventing accumulation and subsequent sticking.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The narrow gap that initially causes liquid accumulation and sticking is transformed into a beneficial structure by adding channels. The same tight fit that prevents rattling now works in conjunction with channels to enable controlled liquid drainage, converting the harmful accumulation effect into a beneficial drainage function.

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

3Shape

If the component is rigidly attached to the vehicle, then the plastic body part deforms irreversibly due to thermal expansion in the paint dryer, but if loosely attached, then rattling occurs

Engineering Contradiction:
Improveaesthetic stylingVSAvoidthermal expansion compensation
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The attachment system transitions from a static rigid connection to a dynamic adjustable connection. The sliding element can move within the longitudinal groove, allowing the body part to dynamically adjust its position in response to thermal expansion while maintaining aesthetic appearance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system allows for parameter changes in the form of sliding element position within the longitudinal groove. This enables the body part to accommodate thermal expansion by changing its relative position to the vehicle structure, preventing irreversible deformation.

Inventive Principle:
Principle #35Parameter changes

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

This solution effectively prevents plastic deformation and reduces rework costs by ensuring smooth sliding movement and improved quality, minimizing rejects and reassembly needs.

Implementation Method 1

plastics are also being used as body parts, which have a significantly higher coefficient of thermal expansion than steel or aluminum. When heated in a paint dryer, a plastic body part expands correspondingly more.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

due to such gap mass and due to the capillary action of a liquid (coating media, KTL, filler, base coat, top coat), e.g. when the paint is drying, the liquid in the gap dries and impedes the sliding properties

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP2228546B1Arrangement of a component on a support
Publication Date: 2014.06.11 BAYERISCHE MOTOREN WERKE AG
  • EP2228546B1 patent drawingFigure 1
  • EP2228546B1 patent drawingFigure 2A~2B
  • EP2228546B1 patent drawingFigure 3

AI summary

The component (101) has a metal sliding element (102) that slidingly engages into a longitudinal groove (104) i.e. sliding-element break-through. A channel discharges liquid between the component and the sliding element in an overlapping region. The channel is implemented as a longitudinal groove (105) or as a transverse groove (106) partly along the longitudinal groove. The channel is provided in the component and/or in the sliding element. The component is made of carbon fiber reinforced plastic, light alloy such as aluminum, magnesium or titanium, or steel.