Fiber Composite Leaf Spring Adhesive Receptacle Connection

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Solution Overview

Problem

Existing leaf spring arrangements for motor vehicle axles face challenges in achieving high mechanical durability while maintaining economical and simple production methods, as traditional methods like drilling and lamination lead to damage and increased costs.

Innovation Solution

A leaf spring arrangement featuring a flat, fiber composite transverse leaf spring with a glued receptacle made of metallic material, where the receptacle is bonded to the leaf spring using a one- or two-component adhesive, avoiding machining and providing a support shoulder for self-centering and compressive force distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the leaf spring is drilled and screwed to the receptacle, then a secure mechanical connection is achieved, but the mechanical durability is reduced due to damage to the fiber composite material

Engineering Contradiction:
Improveconnection strengthVSAvoidmechanical durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the mechanical drilling and screwing system with a chemical bonding system using adhesive. The adhesive is applied between the receptacle and the leaf spring's joining surface, eliminating the need to drill holes through the fiber composite material. This substitution preserves the integrity of the leaf spring while achieving secure connection.

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

Solution Approach 2:

The adhesive acts as an intermediary substance between the receptacle and the leaf spring. It creates a bonding interface that transfers mechanical loads without requiring direct mechanical penetration into the fiber composite material, thus avoiding damage while maintaining connection strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the receptacle is laminated into the leaf spring during manufacturing, then a strong connection is achieved, but production costs increase

Engineering Contradiction:
Improveconnection strengthVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The joining surfaces of both the receptacle and the leaf spring are prepared in advance with appropriate adhesive surfaces. This preliminary preparation allows for simple adhesive application and curing without requiring complex lamination processes during manufacturing, thereby reducing production costs while maintaining connection strength.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The complex lamination process is replaced with a simpler adhesive bonding process. The adhesive provides sufficient bonding strength without requiring the high-pressure, high-temperature conditions associated with lamination, thus simplifying manufacturing and reducing costs.

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

3Manufacturing precision

If the leaf spring ends are machined for screw connections, then precise alignment is achieved, but the structural integrity is compromised

Engineering Contradiction:
Improvealignment precisionVSAvoidstructural integrity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The machining process for creating screw holes is replaced with adhesive bonding. The joining surfaces are designed with precise geometry for adhesive application, but no holes or cuts are made in the leaf spring, preserving its structural integrity while achieving accurate alignment through the adhesive bond.

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

Solution Approach 2:

The joining surfaces are specifically designed with appropriate geometry and surface properties for adhesive bonding. The flat joining surface on the leaf spring and the corresponding surface on the receptacle are optimized for adhesive contact, providing precise alignment without compromising the overall structural integrity of the leaf spring.

Inventive Principle:
Principle #3Local quality

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 enhances durability and cost-effectiveness by eliminating the need for drilling and lamination, ensuring a strong adhesive connection that withstands mechanical stress and simplifies production, while maintaining high mechanical integrity under static and dynamic loads.

Implementation Method 1

the receptacle having a joining surface which is glued to the joining surface of the leaf spring

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

the receptacle having an opening for receiving a metal bearing or a screw bolt... the support shoulder at least partially resting on the front end of the leaf spring

Methodology Applied
Scientific EffectMechanical support and force distribution: Mechanical Force

Data Source

PatentEP2905502B1Leaf spring connection
Publication Date: 2016.08.24 BENTELER AUTOMOBILTECHNIK GMBH
  • EP2905502B1 patent drawingFigure 1
  • EP2905502B1 patent drawingFigure 2a~2b
  • EP2905502B1 patent drawingFigure 3a~3b

AI summary

The present invention relates to a leaf spring arrangement (1) for a motor vehicle axle, comprising a leaf spring made of a fiber composite material, which is coupled at its ends (4) with receptacles (5) for connection to further axle components, wherein the leaf spring is formed flat at least on a lower side (8) at its ends (4) and has a joining surface (9) there, and the receptacle (5) lies flat against the lower side (8) in the area of ​​the joining surface (9) and is bonded to it, is characterized in that the receptacle (5) has an opening (11) for receiving a metal bearing or a screw bolt.