Convex Gear Tooth Edge Grinding for Burr-Free Surface Finish

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional gear manufacturing methods fail to produce smooth, stress-free gear tooth edges due to the use of mechanically controlled machines that cannot achieve precise, programmable edge breaks, leading to manual touch-ups and rough finishes.

Innovation Solution

The use of an electrochemical grinding machine with multi-axis CNC capabilities and super abrasives like cubic boron nitride for creep feed grinding, allowing for the formation of convex, radiused, or tangential edge breaks on gear teeth, eliminating the need for separate edge break grinding and manual finishing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional mechanically controlled machines are used for edge break grinding, then the manufacturing process is simple, but the surface finish is rough and manual touch-up is required

Engineering Contradiction:
Improvesurface finish qualityVSAvoidmachine complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical grinding systems with electrochemical grinding (ECG) technology. The ECG machine uses electrochemical reactions instead of mechanical abrasion to remove material, enabling precise control of the edge break geometry and achieving hyper-smooth surfaces without manual touch-up. The programmable CNC control system coordinates the electrochemical grinding process to create the convex contour with high precision.

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

2Productivity

If separate edge break grinding operation is performed, then edge break can be formed, but additional manufacturing steps and manual touch-up are required

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the tooth shaping operation and edge break formation into a single integrated electrochemical grinding process. The ECG machine performs both functions simultaneously by programming the multi-axis movement to create the convex contour directly during tooth generation, eliminating the need for separate edge break grinding operations and manual touch-up steps.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If sharp edges are left on gear teeth, then manufacturing is easier, but stress concentration occurs reducing gear strength

Engineering Contradiction:
Improvegear strengthVSAvoidedge break precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent changes the geometric parameters of the tooth edge by forming a convex contour with specific radius of curvature instead of leaving sharp edges. The electrochemical grinding process precisely controls the edge break geometry to create a radiused profile that eliminates stress concentration points while maintaining manufacturing efficiency through programmable multi-axis movement.

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

This method produces hyper-smooth, burr-free gear surfaces with reduced stress concentrations, enhancing gear strength and longevity while simplifying the manufacturing process by integrating edge break formation with tooth shaping.

Implementation Method 1

a grinding spindle comprising an electrochemical grinding (ECG) element to remove material from the workpiece

Methodology Applied
Scientific EffectElectrochemical grinding: Electrolysis

Data Source

PatentEP3208023B1Convex gear tooth edge
Publication Date: 2021.09.01 SIKORSKY AIRCRAFT CORP
  • EP3208023B1 patent drawingFigure 1
  • EP3208023B1 patent drawingFigure 2A
  • EP3208023B1 patent drawingFigure 2B

AI summary

A method of manufacturing a gear (100) is provided. The method includes forming a plurality of gear teeth (108) in a surface of a gear, the gear teeth having tooth faces (110) defining tooth edges including tooth edge flanks (314) and tooth edge top land (316) and generating a convex contour at an edge break (318) of at least one of the tooth edge flanks and tooth edge top land.