Gear Flank Line Error Reduction via Dynamic Spindle Coupling

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Solution Overview

Problem

Existing methods for producing toothed workpieces result in periodic flank line shape errors due to radial run-out and pitch errors in cutting tools, which cannot be effectively avoided with conventional machining techniques.

Innovation Solution

The method involves a periodic non-linear coupling ratio and/or periodic change in axial distance between the tool spindle and workpiece spindle to compensate for radial run-out and pitch errors, using a control device to adjust the rotational speeds and axial positions of the spindles, allowing for precise correction of flank line shape errors during machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional machining techniques are used with fixed coupling ratio between spindles, then the machining process is simple and stable, but radial run-out and pitch errors of the cutting tool cause periodic flank line shape errors in the gear teeth

Engineering Contradiction:

Improveflank line shape accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transforming the fixed coupling ratio into a dynamically adjustable one. The control device modifies the coupling ratio between the workpiece spindle and tool spindle based on pre-measured radial run-out and pitch errors, allowing the system to adapt in real-time to compensate for tool inaccuracies and eliminate periodic flank line shape errors.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the coupling ratio from a constant value to a variable parameter that can be adjusted according to the measured errors. By modifying the coupling ratio dynamically, the system compensates for radial run-out and pitch errors, thereby improving flank line shape accuracy without requiring higher precision tooling.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If the coupling ratio is modified to compensate for tool errors, then flank line shape errors are reduced, but the machining process becomes more complex

Engineering Contradiction:

Improvetooth flank geometry accuracyVSAvoidmachining process simplicity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by measuring the radial run-out and pitch errors of the cutting tool before the actual machining process. These measurements are stored and used to pre-calculate the appropriate coupling ratio modifications, so that when machining begins, the compensation is already built into the control parameters, simplifying the execution phase.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by using the pre-measured error data to continuously adjust the coupling ratio during machining. The control device incorporates the measured radial run-out and pitch errors into the coupling ratio calculation, creating a closed-loop compensation mechanism that maintains high accuracy throughout the machining process.

Inventive Principle:

Principle #23Feedback

3Productivity

If radial run-out and pitch errors are not compensated, then the machining process is fast and efficient, but periodic flank line shape errors occur in the gear teeth

Engineering Contradiction:

Improvemachining efficiencyVSAvoidflank line shape accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of radial run-out and pitch errors into a beneficial compensation mechanism. By measuring these errors and incorporating them into the coupling ratio modification, the system transforms what would be sources of inaccuracy into data that enables precise compensation, maintaining both efficiency and accuracy.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS10449613B2Method and device for forming teeth in a workpiece gear with reduced flank line shape error

Publication Date: 2019.10.22 PROFILATOR

AI summary

A method for producing a toothed workpiece gear, wherein the workpiece gear is clamped or fastened to a workpiece spindle, and a cutting tool having cutting teeth is clamped or fastened to a tool spindle. The tool spindle and the workpiece spindle are rotationally driven at a coupling ratio of the angles of rotation thereof having a periodic non-linearity or an axial distance from each other that changes periodically. The cutting teeth machine forms left and right tooth flanks of the teeth of the workpiece gear using left and right cutting edges in a chip-removing manner. A radial run-out error or a pitch error of the cutting tool is determined. The flank line shape errors of the right and left tooth flank resulting from the radial run-out error or the pitch error are reduced by the periodic non-linearity of the coupling ratio or the periodic change in the axial distance.