Asymmetrical Chamfering Worm for Faster Gear Tooth Edge Machining

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Solution Overview

Problem

Existing chamfering tools for gear teeth machining either result in long machining times or compromise on machining accuracy and flexibility, and there is a need for a tool that balances these factors effectively.

Innovation Solution

A chamfering tool with a worm-shaped gearing having multiple teeth with a geometrically defined cutting edge, designed for single-flank machining with an asymmetrical tooth profile, allowing for efficient rolling machining engagement and distributing tool wear evenly, thus achieving better processing times and flexibility in chamfer design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If plastic deformation method is used with chamfering wheel, then flexibility in chamfer design is improved, but machining time increases and surface quality deteriorates

Engineering Contradiction:
Improveflexibility in chamfer designVSAvoidmachining time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent replaces the plastic deformation mechanism (chamfering wheel rolling against tooth edge) with a cutting mechanism (geometrically defined cutting edges on hob cutter teeth). This substitution enables material removal through cutting rather than displacement, significantly reducing machining time while maintaining flexibility through tool reprofiling capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables parameter changes by allowing the cutting edges to be reprofiled on the hob cutter. This means chamfer parameters (angle, width, depth) can be modified by changing the tool profile without replacing the entire tool, maintaining flexibility while using efficient cutting methodology.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If grinding chamfering method is used, then surface quality is improved and flexibility is enhanced, but machining time increases

Engineering Contradiction:
Improvesurface qualityVSAvoidmachining time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent substitutes the grinding mechanism with a cutting mechanism using geometrically defined cutting edges. The cutting edges are designed to produce a chamfered surface with high quality through precise cutting engagement in rolling motion, eliminating the need for grinding while maintaining surface quality and reducing machining time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If single-flank machining with asymmetrical tooth profile is used, then machining accuracy and tool wear distribution are improved, but tool design complexity increases

Engineering Contradiction:
Improvemachining accuracyVSAvoidtool design complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by designing the hob cutter with an asymmetrical tooth profile where one flank has geometrically defined cutting edges for machining and the other flank is non-machining. This asymmetrical design enables single-flank machining that improves accuracy and distributes wear evenly across multiple teeth while the complexity is managed through the systematic design of the asymmetrical profile.

Inventive Principle:
Principle #4Asymmetry

4Reliability

If multiple teeth per worm thread are provided, then tool wear distribution is improved and machining accuracy is enhanced, but tool design complexity increases

Engineering Contradiction:
Improvetool service lifeVSAvoidtool design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by providing multiple teeth (at least two, preferably at least four) on each worm thread of the hob cutter. This segmentation distributes the cutting load across multiple teeth, improving tool service life through even wear distribution and enhancing machining accuracy through multiple cutting engagements, while the complexity is systematically managed through the multi-tooth worm gear design.

Inventive Principle:
Principle #1Segmentation

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 balance between machining time and accuracy, offering longer tool service life and flexibility in chamfer design, while ensuring high surface quality and efficient processing of both left and right flanks of gear teeth.

Implementation Method 1

a rolling motion is created between the profile cutter and the toothing such that the cutter tooth immediately following one cutter tooth cuts the tooth gap immediately following the first cut gap

Methodology Applied
Scientific EffectRolling motion:

Implementation Method 2

the chamfer on the tooth edge is created by cutting. Fly cutters are used for this purpose with a chamfering edge shape independent of the tooth profile

Methodology Applied
Scientific EffectCutting:

Implementation Method 3

the chamfer on one flank of the workpiece gear teeth is produced by several successive engagements of different teeth and thus consists of several circumferential cuts by the chamfering worm. Due to the cutting machining, better machining times are achieved than, for example, with grinding chamfering. The tool design with multiple teeth per worm thread distributes tool wear across several teeth, resulting in more favorable load distribution.

Methodology Applied
Scientific EffectWear distribution: Wear

Data Source

PatentEP3758876B1Chamfering tool, chamfering system, gear-cutting machine and method for chamfering toothings
Publication Date: 2021.11.03 GLEASON PFAUTER MASCHFAB
  • EP3758876B1 patent drawingFigure 1
  • EP3758876B1 patent drawingFigure 2
  • EP3758876B1 patent drawingFigure 3

AI summary

The invention relates to a chamfering tool (4) for chamfering workpiece toothings (22), comprising a helical toothing, which has, for each spiral, a plurality of teeth (5) having a geometrically defined cutting edge and which has a tooth profile (8, 9; 8', 9') that is designed for single-flank machining in rolling machining engagement with the workpiece toothing and that is asymmetrical when seen in axial section of the tool. The invention further relates to a chamfering system (100), to a gear-cutting machine, and to a method for producing a chamfer on the tooth edges of a tooth flank side of a workpiece toothing.