Hierarchical Surface Structure for Durable Gas-Tight Bonding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing composite components in motor vehicles, particularly in the engine compartment, face challenges in maintaining high strength and permanent gas-tightness under temperature and load changes, as well as media exposure, due to temporary gas-tightness caused by shrinkage stresses and lack of durable adhesive connections.

Innovation Solution

A composite component is created with a microstructure overlaid by a nanostructure on both contact surfaces, using electromagnetic radiation such as laser processing with ultra-short pulses under inert gas, ensuring strong and tight connections through partial encapsulation and shared thermal expansion coefficients, and optionally using adhesives with adhesion promoters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If macroscopic structures with undercuts are used to enable positive fit with plastic material, then initial gas-tightness can be achieved, but the gas-tightness is temporary and cannot withstand temperature and load changes

Engineering Contradiction:
Improvegas-tightnessVSAvoiddurability of connection
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The surface structure is segmented into multiple hierarchical levels: macroscopic structures (10 μm to 1 mm) providing positive fit, microscopic structures (1 μm to 10 μm) increasing surface area, and nanoscopic structures (1 nm to 1 μm) creating chemical bonding sites. This multi-scale segmentation allows each level to contribute differently to the overall connection strength and gas-tightness durability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite surface structure combining multiple length scales and material properties. The hierarchical composite structure integrates mechanical interlocking (macro), physical adsorption (micro), and chemical bonding (nano) mechanisms, resulting in a connection that maintains gas-tightness under varying temperature and load conditions.

Inventive Principle:
Principle #40Composite materials

2Strength

If adhesive connection is used to connect components, then bonding strength can be improved, but the connection lacks permanent gas-tightness under environmental stress

Engineering Contradiction:
Improvebonding strengthVSAvoidpermanent gas-tightness
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention merges multiple connection mechanisms into a unified surface structure: mechanical interlocking through macroscopic undercuts, physical adsorption through increased surface area from microstructures, and chemical bonding through nanoscopic structures. This combination creates a connection that is both strong and permanently gas-tight under environmental stress.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Different regions of the surface structure provide different functions: macroscopic structures provide mechanical interlocking in load-bearing areas, while nanoscopic structures provide chemical bonding sites in areas requiring gas-tightness. This local differentiation of surface properties optimizes both strength and sealing performance.

Inventive Principle:
Principle #3Local quality

3Strength

If laser radiation is used to produce surface structure, then connection strength can be enhanced, but the process requires precise control of multiple parameters

Engineering Contradiction:
Improveconnection strengthVSAvoidprocess control complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The laser processing uses periodic pulsed radiation to create the hierarchical surface structure. By controlling the pulse frequency, duration, and intensity, the process systematically creates macro, micro, and nano structures in sequence, making the complex structuring process controllable and repeatable.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention utilizes changes in laser parameters (wavelength, pulse duration, power density) to selectively create different structural levels. By adjusting these parameters, the same laser system can produce macroscopic undercuts, microscopic roughness, and nanoscopic features, simplifying the overall process while achieving complex surface morphology.

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

The solution achieves reliable and permanent gas-tight connections capable of withstanding temperature and load fluctuations, enhancing the durability and performance of components like fuel injection valves and housing covers by forming strong adhesive forces and chemical sealing.

Implementation Method 1

it is provided that the first contact surface is provided with a surface structure by means of a laser beam

Methodology Applied
Scientific EffectLaser irradiation: Laser

Implementation Method 2

the radiation wavelength of the electromagnetic radiation used, in particular the laser radiation, is selected from a value range between approximately 10 nm and approximately 11 μm

Methodology Applied
Scientific EffectElectromagnetic radiation absorption: Absorption (EM radiation)

Implementation Method 3

it is further preferred if an ultra-short pulse laser is used for this purpose

Methodology Applied
Scientific EffectUltra-short pulse processing: Pulsed Laser Deposition

Data Source

PatentEP2467256B1Component composite and method for manufacturing a component composite
Publication Date: 2013.10.30 ROBERT BOSCH GMBH
  • EP2467256B1 patent drawingFigure 1~3

AI summary

The invention relates to a component composite, particularly for motor vehicle applications, comprising a first component (1) having a first contact surface (3), wherein the first contact surface (3) has a surface structure (6) having a microstructure (7) that is superimposed with a nanostructure (10), and at least a second component (4) having a second contact surface (5). According to the invention, a medium, particularly an adhesive layer (12), is arranged between the two contact surfaces (3, 5) of the two components (1, 4) for bonded connection.