Vacuum Machining of Metal Components for Wear-Reducing Oxide Layers

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Solution Overview

Problem

Components in internal combustion engines, such as common rail injectors, experience wear due to high pressures and temperatures, leading to drifts in injection quantity and potential emission limit violations, with existing diamond-like carbon coatings being expensive and complex.

Innovation Solution

A method involving a closed, vacuum-capable housing around the metallic component to create a low-oxygen environment, reducing the formation of the brittle oxide Fe2O3 and increasing the formation of the less brittle and harder wear-reducing oxide Fe3O4, which is achieved by maintaining a pressure between 10^-3 and 10^-6 bar within the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diamond-like carbon coatings are applied to protect surfaces from wear, then wear resistance is improved, but manufacturing complexity and cost increase

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

Solution Approach 1:

The patent applies vacuum technology to create an inert environment during the machining process. By maintaining vacuum conditions in the processing chamber, the method prevents oxidation and wear without requiring complex diamond-like carbon coatings. The vacuum environment acts as a protective medium that eliminates the need for additional coating layers, thereby reducing manufacturing complexity while maintaining wear resistance.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If diamond-like carbon coatings are applied to reduce wear, then surface durability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvesurface durabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The vacuum-capable housing creates an inert environment that protects surfaces from wear during machining and operation. This eliminates the need for expensive diamond-like carbon coatings while maintaining surface durability. The vacuum environment prevents oxidative wear and material degradation, providing cost-effective protection through environmental control rather than material application.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Reliability

If vacuum environment is created to reduce oxide formation, then wear reduction is achieved, but device complexity increases

Engineering Contradiction:
Improvewear reductionVSAvoidvacuum system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The vacuum-capable housing combines the machining chamber and the protective environment into a single integrated structure. The housing serves dual functions: it contains the machining operation and simultaneously maintains the vacuum environment for wear protection. This merging eliminates the need for separate vacuum systems and coating processes, reducing overall device complexity while achieving wear reduction.

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If vacuum machining is used to create wear-reducing oxide layers, then surface quality is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvesurface qualityVSAvoidvacuum housing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The vacuum-capable housing integrates the protective environment function directly into the machining structure. By combining the vacuum chamber with the machining workspace, the system achieves precise control over oxide layer formation without requiring complex external vacuum systems. The integrated design maintains surface quality while minimizing additional complexity through functional consolidation.

Inventive Principle:
Principle #5Merging (Combining)

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 approach reduces wear on the metallic component surfaces without the need for costly coatings, minimizing friction and adhesive wear while ensuring sufficient oxide layer formation.

Implementation Method 1

a closed, vacuum-capable housing (5) arranged to accommodate at least part of the surface of the metallic component (1) to be machined, the vacuum-capable housing (5) being fluidically connected to at least one vacuum-generating means (4) for generating a low-oxygen environment in the vacuum-capable housing (5)

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

The creation of a negative pressure within the negative pressure housing lowers the oxygen content of the air within the negative pressure housing and reduces the formation of the main oxide Fe 2 O 3 . Instead, the wear-reducing oxide Fe 3 O 4 is increasingly formed

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP3092085B1Method for machining a metal component
Publication Date: 2022.11.23 ROBERT BOSCH GMBH
  • EP3092085B1 patent drawingFigure 1
  • EP3092085B1 patent drawingFigure 2
  • EP3092085B1 patent drawingFigure 3

AI summary

The invention relates to a device for machining a metallic component (1), comprising a machining tool (2) for machining a surface of the metallic component (1) and a holding device (3) for receiving the metallic component (1) as well as at least one negative pressure-generating means (4). A closed vacuum-compatible housing (5) is provided for receiving at least a part of the surface of the metallic component (1), which is to be machined, wherein the vacuum-compatible housing (5) is connected in a fluidic manner to the at least one negative pressure-generating means (4) for generating a low-oxygen environment in the vacuum-compatible housing (5).