Smoothing Gears for Gear Tooth Flanks with Thrust Ring

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Solution Overview

Problem

Existing devices for smoothing internal and external toothing, such as ring gears, often result in surface roughness due to broaching processes, leading to micropitting and pitting issues, and are complex and require multiple processing stations with high force requirements.

Innovation Solution

A device with radially adjustable smoothing gears arranged in a single processing station, allowing for loose support of the component and using thrust rings to limit axial movement, along with oscillating gears to compensate for inclination, and differently profiled gears to smooth various zones of the tooth flanks simultaneously, reducing surface roughness and processing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple processing stations with smoothing gears are used to smooth internal and external toothing, then the surface quality is improved, but the device complexity and force requirements increase significantly

Engineering Contradiction:
Improvesurface qualityVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple smoothing operations into a single processing station by arranging multiple smoothing gears (at least two) that can simultaneously engage with different zones of the internal and/or external toothing. This merging of functions reduces device complexity while maintaining the ability to smooth the entire toothed component comprehensively

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The smoothing gears are designed with universal applicability to handle both internal and external toothing configurations. The same basic smoothing gear design can be applied to different zones and types of gearing, reducing the need for specialized equipment for each specific smoothing task

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If the component is firmly clamped during smoothing, then the positioning is stable, but the axial play prevents proper engagement of smoothing gears with the component

Engineering Contradiction:
Improvepositioning stabilityVSAvoidengagement precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent employs a dynamic support system where the component rests loosely on a support rather than being firmly clamped. This allows the component to have minimal axial play (a few tenths of a millimeter) while still maintaining stable positioning. The thrust ring provides dynamic constraint only when needed to limit axial movement, accommodating the natural flexibility of the component

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A thrust ring is introduced as an intermediary element between the smoothing gear and the component. This thrust ring limits the axial movements of the component during smoothing, enabling proper engagement of the smoothing gears while maintaining loose support. The thrust ring acts as a mediator that provides just enough constraint to enable precise engagement without requiring firm clamping

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If high contact pressure is applied by smoothing gears, then the smoothing effect is stronger, but the force requirements and device complexity increase

Engineering Contradiction:
Improvesmoothing effectVSAvoidforce requirements
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The smoothing operation is segmented across multiple smoothing gears that engage with different zones of the toothing. By dividing the total smoothing task among several gears (at least two), each gear operates with lower contact pressure and force requirements, yet collectively they achieve comprehensive smoothing of the entire component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by having different smoothing gears target specific zones of the toothing rather than requiring all gears to apply maximum pressure to the entire surface. This distributed approach achieves effective smoothing with reduced force requirements compared to concentrated high-pressure application

Inventive Principle:
Principle #16Partial or excessive action

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 improved surface quality with reduced force requirements and simplified device design, effectively preventing micropitting by smoothing the tooth flanks in a single station with minimal axial play, enhancing the durability of gear components.

Implementation Method 1

the smoothing gears are brought into engagement with the internal and/or external toothing of a component and thus cause smoothing of the internal and/or external toothing

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

The oscillatingly mounted smoothing gears compensate for the very slight inclination of the component to be machined

Methodology Applied
Scientific EffectOscillation: Harmonic Oscillator

Implementation Method 3

a thrust ring is provided on at least one—preferably on each—of the smoothing gears, which limits the axial movements of the component that occur during smoothing

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP3016771B1Apparatus for smoothing a toothing system and production process for a toothing system
Publication Date: 2019.11.13 ZF FRIEDRICHSHAFEN AG
  • EP3016771B1 patent drawingFigure 1
  • EP3016771B1 patent drawingFigure 1B
  • EP3016771B1 patent drawingFigure 2

AI summary

The invention relates to an apparatus for smoothing an internal and/or an external toothing system (4a) of a component (4). It is proposed that at least two radially advanceable smoothing gearwheels (A, B, C) which engage into the internal toothing system (4a) and/or the external toothing system are arranged rotatably on the inside of the internal toothing system (4a) and/or on the outside of the external toothing system. During the smoothing operation, the component (4; 14) is not firmly clamped, but instead rests only loosely on a support (5). To limit axial movements of the component (4; 14) which occur during the smoothing operation, a thrust ring (6) is provided on at least one of the smoothing gearwheels (A, B, C; Ai, Bi, Ci, Aa, Ba, Ca).