Gear Tooth Flank Machining for Hybrid Motion Error Control

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Solution Overview

Problem

Bevel and hypoid gears experience noise due to parabolic motion errors caused by crowning, which limits smooth rolling and increases the risk of tooth damage, while existing solutions like double wave forms only reduce noise but not eliminate it.

Innovation Solution

A method of machining gear tooth flanks to produce a hybrid motion graph curve comprising sinusoidal and parabolic portions, achieved by specific tool paths and flank geometries that minimize noise and allow higher load transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If crowning is applied to limit contact area and prevent tooth damage, then tooth protection is improved, but motion error increases causing noise

Engineering Contradiction:

Improvetooth protectionVSAvoidnoise

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the motion error function from a traditional parabolic form to a hybrid sinusoidal-parabolic form. This parameter change in the motion graph function allows the contact area to remain within tooth boundaries (maintaining tooth protection) while reducing the magnitude of motion error and its derivatives, thereby reducing noise generation from acceleration peaks.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If crowning is increased to protect teeth from edge contact damage, then tooth protection is improved, but motion error increases preventing smooth rolling

Engineering Contradiction:

Improvetooth protectionVSAvoidsmooth rolling

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent modifies the motion graph function parameters to create a hybrid sinusoidal-parabolic form. This change allows for better control of the contact area position and size while reducing the severity of velocity steps and acceleration peaks, enabling smoother rolling operation while maintaining tooth protection.

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If double wave form is used to reduce noise, then noise reduction is achieved, but noise peaks are not completely eliminated

Engineering Contradiction:

ImprovenoiseVSAvoidnoise elimination

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent transitions from a double wave form to a hybrid sinusoidal-parabolic motion graph function. This parameter change in the mathematical description of tooth flank geometry enables complete elimination of acceleration peaks and noise, achieving a fundamental improvement over the double wave approach which could only reduce but not eliminate noise.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11331734B2Method of machining gears to produce a sinusoidal-parabolic hybrid motion error, gear thus produced and machine for performing said method

Publication Date: 2022.05.17 THE GLEASON WORKS

AI summary

A method of machining a tooth flank of a gear with a gear machining tool. The method comprises rotating the tool and bringing the tool and the tooth flank into contact. Relative movements are provided between the tool and the gear to traverse the tool across the tooth flank along a path whereby the path produces a tooth flank geometry of a form which, when brought into mesh with a mating tooth flank under no load or light load to form a tooth pair, provides a motion graph curve comprising a sinusoidal portion (62, 89, 91, 90, 63) and a parabolic portion (92).