Form-Fit Fastening Set for Fiber Composite Components

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Solution Overview

Problem

Existing fastening systems for fiber composite components are complex and difficult to assemble, requiring permanent connections such as gluing or welding, which complicates the installation process and limits flexibility in positioning and replacement.

Innovation Solution

A fastening set with a form-fitting shaft and flange design that allows for easy assembly and replacement, featuring a cross-sectional geometry for anti-rotation and transverse displacement, and utilizes elastically deformable snap hooks for secure engagement without permanent attachment, enabling correction of positioning errors and secure clamping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the flange section is permanently connected to the fiber composite component via gluing or welding, then the fastening set achieves secure attachment, but the assembly process becomes complex and time-consuming

Engineering Contradiction:
Improvesecure attachmentVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces chemical bonding (gluing) or thermal bonding (welding) with a mechanical form-fit connection. The shaft section with non-circular cross-section inserts into a correspondingly shaped through-hole, creating a mechanical interlock that eliminates the need for adhesives or welding operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fastening element performs self-positioning and self-centering through its non-circular cross-sectional geometry. The form-fit connection automatically aligns the shaft with the through-hole during insertion, eliminating the need for complex alignment procedures or additional positioning fixtures.

Inventive Principle:
Principle #25Self-service

2Stability of the object's composition

If the flange section is permanently connected to the fiber composite component, then the fastening set achieves stable attachment, but replacement and repositioning become difficult

Engineering Contradiction:
Improveattachment stabilityVSAvoidreplacement ease
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

The patent creates a dynamic fastening system where the screw element can be independently tightened or loosened to adjust the clamping force. This allows the fastening set to transition between a loose state (for installation or replacement) and a tightly clamped state (for stable operation), providing both ease of replacement and operational stability.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the through-hole positioning is precisely manufactured, then the fastening set achieves accurate positioning, but manufacturing costs and complexity increase

Engineering Contradiction:
Improvethrough-hole positioning accuracyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces a tolerance range for the through-hole positioning by designing the shaft section with a non-circular cross-section that is smaller than the through-hole dimensions. This parameter change allows the fastening element to accommodate manufacturing variations while maintaining functional accuracy, reducing the need for high-precision manufacturing.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If the shaft has a non-circular cross-section for anti-rotation, then rotational stability is improved, but the fastening element becomes more complex to manufacture

Engineering Contradiction:
Improverotational stabilityVSAvoidfastening element manufacturing
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent uses a composite construction where the shaft section is made of a material different from the flange section. This allows optimization of each part for its specific function: the shaft can be manufactured from a material suitable for the non-circular cross-section and form-fit connection, while the flange can be made from a different material optimized for clamping and structural support.

Inventive Principle:
Principle #40Composite materials

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

Simplifies the assembly process, allows for easy replacement, and ensures secure, positionally fixed attachment of the fastening set to the fiber composite component, even in the presence of manufacturing-related positioning errors, without the need for adhesive bonding or permanent attachments.

Implementation Method 1

elastically deformable snap hooks latched in the edge region of the through bore

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2667041B1Fastening set for a composite fibre component
Publication Date: 2020.06.03 BAYERISCHE MOTOREN WERKE AG
  • EP2667041B1 patent drawingFigure 1a~2
  • EP2667041B1 patent drawingFigure 3a~3b

AI summary

The fastening set has a fastening element (5) which comprises a shaft and a flange that is expanded on the component rear side (9). The shaft is inserted in a through hole (1) of the fiber composite component. The fastening element is supported in sliding manner on the component front side (12) on the shaft end. The fastening element is formed of plastic. The cross-sectional geometry of the shaft and the through hole of the fiber composite component are configured such that the fastening element is movably limited transverse to the shaft axis and is arranged in the component bore in rotation-proof manner around the shaft axis, in the tightened position of a screw element (3) but is clamped with the fiber composite component in fixed position.