Aluminum Diecast Spring Support Coated for Steel Bonding

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Solution Overview

Problem

Existing vehicle body constructions face challenges in achieving high corrosion resistance when combining aluminum die-cast spring supports with steel front body structures, necessitating effective anti-corrosion measures.

Innovation Solution

A vehicle body with a light metal component coated using a cathode dip coating process, where the adhesive layer is applied directly to the coating, preventing contact corrosion and ensuring strong bonding with steel components, and press-fit elements are coated simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum die-cast spring supports are installed in a steel front body structure, then lightweight construction is achieved, but corrosion resistance deteriorates due to contact corrosion risk

Engineering Contradiction:
Improvevehicle body weightVSAvoidcorrosion resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

A cathode dip coating layer is applied as an intermediary between the aluminum spring support and the adhesive layer. This coating serves as a protective mediator that prevents direct contact between dissimilar metals, eliminating galvanic corrosion risk while maintaining the lightweight aluminum construction.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cathode dip coating is applied to the aluminum spring support surface before adhesive bonding. This preliminary protective action prevents contact corrosion from occurring during the bonding process and throughout the service life of the vehicle, ensuring long-term reliability of the mixed-material construction.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a protective coating is applied to the aluminum spring support, then corrosion resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcoating process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cathode dip coating process is self-service in nature, where the aluminum spring support itself acts as the cathode during the electrochemical deposition. The aluminum surface naturally facilitates the deposition of the protective coating layer without requiring additional complex equipment or multi-step processes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cathode dip coating process combines the protective coating application with the existing aluminum spring support manufacturing process. The coating is applied in a single integrated step before assembly, merging the corrosion protection function with the structural component fabrication rather than adding separate complex operations.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If adhesive layer is applied directly to the aluminum surface, then bonding strength is improved, but contact corrosion risk increases

Engineering Contradiction:
Improveadhesive bonding strengthVSAvoidcontact corrosion risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The cathode dip coating layer serves as an intermediary between the aluminum spring support and the adhesive layer. This intermediate layer prevents direct galvanic contact between the aluminum and the adhesive/steel components, eliminating corrosion risk while maintaining effective adhesive bonding to the coating surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cathode dip coating provides localized corrosion protection specifically at the interface where the adhesive bonds to the aluminum spring support. This local quality enhancement targets the precise area most susceptible to contact corrosion, providing protection without requiring coating of the entire component.

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

The solution provides a robust and cost-effective corrosion-resistant mixed construction by avoiding contact corrosion and ensuring reliable bonding between dissimilar materials, enhancing process reliability and structural integrity.

Implementation Method 1

The surface of the first body component is provided with a coating which has been applied to the surface of the first body component in a cathode dip coating process

Methodology Applied
Scientific EffectCathode dip coating: Electroplating

Implementation Method 2

a first body component which is made of a light metal material and which is connected by means of an adhesive layer to a second body component which is made of a different material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP1882625B1Car bodywork with aluminium diecast spring support coated with cataphoretic paint
Publication Date: 2009.02.11 BAYERISCHE MOTOREN WERKE AG

AI summary

The vehicle body has a body component, which is made of a light alloy material. The component is connected by an adhesive layer with another body component, which is made of another material. A surface of the first body component is provided with a coating, which was applied during a cathode immersion painting process on the surface, where the adhesive layer is directly applied on the coating. The former body component is a suspension strut support and an aluminum diecast part.