Gear Coating via Periodic Rotation and Shielding

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Solution Overview

Problem

Existing methods for coating gear tooth flanks using plasma deposition result in insufficient layer quality due to changing tooth flank alignment relative to the irradiation direction, leading to inadequate adhesion and hardness of the coating, particularly in high-load applications like motor vehicle transmissions.

Innovation Solution

The method involves intermittently or non-uniformly rotating the component and coating source relative to each other, with longer dwell times at steep angles of functional surfaces to ensure optimal coating material impact, using a screen to shade critical areas and combining with electrical and magnetic fields for improved guidance and intensity of the plasma jet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If continuous rotation is used during coating, then all tooth flanks can be coated, but the changing alignment results in insufficient layer adhesion and quality

Engineering Contradiction:
Improvecoating coverageVSAvoidlayer quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies periodic action by intermittently rotating the gear wheel during coating, with longer dwell times at rotational positions where functional surfaces are steeply aligned to the irradiation direction. This ensures optimal coating deposition during stationary phases while periodically repositioning to coat different tooth flanks.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses preliminary action by pre-positioning the gear wheel at specific rotational angles where functional surfaces are optimally aligned (steep angles) before initiating coating deposition. This ensures that coating material strikes the surface at optimal angles for adhesion and hardness before the alignment changes during rotation.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the gear wheel rotates during coating, then all tooth flanks can be coated, but the angle of incidence decreases leading to reduced penetration depth and layer quality

Engineering Contradiction:
Improvetooth flank coverageVSAvoidpenetration depth
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The gear wheel performs periodic rotation with intermittent stopping at positions where tooth flanks are steeply aligned to the irradiation direction. This ensures that coating deposition occurs primarily when the angle of incidence is optimal for penetration depth and layer quality, while still achieving comprehensive coverage over multiple rotation cycles.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the rotation speed and timing of the gear wheel during coating, with variable dwell times at different rotational positions. This dynamic control ensures optimal angle of incidence during deposition phases while maintaining the ability to coat all tooth flanks through continued rotation.

Inventive Principle:
Principle #15Dynamics

3Productivity

If coating material is emitted continuously, then coating efficiency is high, but material is wasted on non-functional surfaces and critical areas remain insufficiently coated

Engineering Contradiction:
Improvecoating rateVSAvoidcoating material waste
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The patent applies local quality by using a screen with selectively positioned apertures that direct coating material only onto functional surfaces (tooth flanks) while shielding non-functional areas. This ensures coating material is deposited precisely where needed, reducing waste while maintaining high coating rates on critical surfaces.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The screen acts as an intermediary element between the coating material source and the gear wheel, selectively transmitting coating particles to functional surfaces while blocking them from non-functional areas. This mediator ensures efficient material utilization by directing the coating beam only where adhesion and quality are critical.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If a screen is used to shade critical areas, then coating precision is improved, but coating intensity is reduced due to particle interception

Engineering Contradiction:
Improvecoating accuracyVSAvoidcoating intensity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The screen is designed with localized apertures positioned to provide precise shading of non-functional surfaces while maintaining open pathways for coating material to reach functional surfaces. This selective local transmission ensures high coating accuracy on tooth flanks without significant interruption of coating intensity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The screen is positioned in a spatial dimension between the coating source and the gear wheel, creating a three-dimensional filtering effect. This dimensional arrangement allows the screen to shade critical areas from certain angles while maintaining coating material flow to functional surfaces from optimized directions, preserving both precision and intensity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 results in a high-quality, integral coating with enhanced tribological properties, ensuring superior adhesion and hardness on the tooth flanks, particularly on the heavily loaded sides of gear wheels, while optimizing coating efficiency and material usage.

Implementation Method 1

a plasma generated by a coating source, for example based on graphite and accelerated in an electric or magnetic field

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

plasma particles are transformed into an extremely hard, diamond-like coating

Methodology Applied
Scientific EffectIon implantation: Ion Implantation

Implementation Method 3

accelerated in an electric or magnetic field

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 4

accelerated in an electric or magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 5

the structurally simple shading of the component hides the critical circumferential area in which the functional surfaces of the component are set at a shallow angle to the irradiation direction

Methodology Applied
Scientific EffectShadowing: Shadow

Implementation Method 6

an ion or plasma jet is preferably used as the coating material, which is additionally deflected with an electrical and/or magnetic field with a view to improved guidance

Methodology Applied
Scientific EffectElectrical field deflection: Electric Field

Implementation Method 7

an ion or plasma jet is preferably used as the coating material, which is additionally deflected with an electrical and/or magnetic field with a view to improved guidance

Methodology Applied
Scientific EffectMagnetic field deflection: Magnetic Field

Implementation Method 8

the coating beam is bundled in such a way that part of the coating particles otherwise intercepted by the diaphragm are deposited on the functional surface with an increase in coating intensity

Methodology Applied
Scientific EffectBeam focusing: Focusing

Data Source

PatentEP2376667B8Method for coating functional surfaces
Publication Date: 2016.05.18 BAYERISCHE MOTOREN WERKE AG

AI summary

The invention relates to a method and to a device for coating the functional surfaces of symmetrically serrated components, in particular the tooth flanks (3) of gears (1), having a coating source (2) emitting the coating material in the form of electrically charged particles in the direction of the component and revolving relative to said component, wherein, according to the invention, a high-quality functional surface coating of the component is achieved in a technologically simple manner in that a shield (4) shielding the component from the coating beam in a circumferential area having a functional surface orientation flat to the direction of irradiation is disposed in the beam path between the component (1) and the coating source (2) transverse to the direction of irradiation.