Bevel Gear Tooth Flank Correction Without Re-Clamping

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Solution Overview

Problem

Bevel gear machining using the dipping process often results in topography errors such as flank angle errors, which cannot be corrected to zero due to the limitations of single machine settings, leading to averaged corrections that are only possible if errors differ in magnitude.

Innovation Solution

A method involving combined post-processing or corrective machining of bevel gear tooth flanks, where workpiece rotation and adjustments to machine settings allow for separate machining of concave and convex flanks, enabling precise correction of flank angle errors without re-clamping or tool changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single machine setting is used for plunging to machine both concave and convex tooth flanks, then productivity is improved, but manufacturing precision deteriorates due to inability to correct flank angle errors to zero

Engineering Contradiction:
ImproveproductivityVSAvoidflank angle error correction
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the machining process into two distinct phases: a plunging phase for initial material removal and a corrective machining phase for precision correction. This segmentation allows each phase to use optimized machine settings - the plunging phase maintains high productivity with single machine settings, while the corrective phase achieves high precision with adjusted machine settings including workpiece rotation and modified tool paths.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If separate machining of individual flanks is performed to correct flank angle errors, then manufacturing precision is improved, but device complexity and operation time increase

Engineering Contradiction:
Improveflank angle error correctionVSAvoidmachine setting complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the corrective machining operations for both concave and convex flanks into a single unified process step. By implementing corrective machining for both flanks simultaneously after the plunging operation, the system avoids the complexity of separate machining operations while achieving high precision correction. The workpiece rotation and adjusted machine settings apply to both flanks in one coordinated action.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If workpiece rotation is applied during corrective machining to correct flank angle errors, then manufacturing precision is improved, but the process time increases

Engineering Contradiction:
Improveflank angle error correctionVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs the time-consuming corrective machining operation immediately after the plunging operation while the workpiece is already positioned and clamped. By combining the corrective machining with the existing workpiece setup and performing it in a coordinated manner with workpiece rotation, the system minimizes additional setup time and tool changes, thereby reducing the overall time penalty despite the added precision step.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3375555B1Method for processing the tooth flanks of bevel gear workpieces
Publication Date: 2024.07.24 KLINGELNBERG AG
  • EP3375555B1 patent drawingFigure 1A~1C
  • EP3375555B1 patent drawingFigure 2A~2B
  • EP3375555B1 patent drawingFigure 3A~3B

AI summary

Method for machining the tooth flanks of a bevel gear workpiece, with the following sub-steps - carrying out corrective machining (KB) of the concave tooth flank and the convex tooth flank of at least one tooth gap by o cutting free the concave tooth flank by rotating the bevel gear workpiece relative to the gear cutting tool in a first direction of rotation with a predetermined performs the first amount and/or free-cutting the convex tooth flank by the bevel gear workpiece rotating the workpiece relative to the gear cutting tool in a different direction of rotation by a predetermined second amount, and o reworking the concave tooth flank with a second machine setting (M2), which differs from the first machine setting ( M1), and o finishing the convex tooth flank with a third machine setting (M3) that differs from the second machine setting (M2).