Variable Flank Profile Ring Gear for Wind Turbine Load Distribution

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Solution Overview

Problem

Conventional tooth trace correction methods in gearboxes, particularly in wind power plants, fail to efficiently address varying load conditions caused by planetary wheel carriers connected to mechanical loads, leading to uneven torque distribution and reduced durability.

Innovation Solution

The gearbox features a stationary gear component with teeth having individually adjusted tooth flank profiles along the tooth trace, which are adapted based on positional and directional parameters to compensate for varying stress conditions, ensuring even load distribution and reduced compressive stress peaks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional tooth trace correction methods are applied to gear teeth, then manufacturing complexity is reduced, but load distribution becomes uneven and durability decreases

Engineering Contradiction:
Improvetooth fabrication simplicityVSAvoidgear durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies different tooth flank profiles to different teeth along the tooth trace based on their specific positional and load characteristics. Each tooth's flank profile is individually adapted to its local conditions, transforming the uniform manufacturing approach into a localized optimization strategy that improves load distribution and durability without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the tooth flank profile parameters (such as alpha_wt, phi, and delta_f) based on the position of each tooth along the tooth trace. By changing these geometric parameters locally rather than uniformly, the invention achieves better load distribution and durability while maintaining a systematic approach to manufacturing.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If gear components are dimensioned closely to material fatigue limits to reduce weight, then power-to-weight ratio increases, but durability and reliability decrease

Engineering Contradiction:
Improvegearbox weightVSAvoidcomponent durability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent optimizes the tooth flank profiles locally to distribute loads more evenly across all teeth. This localized optimization prevents stress concentrations that would otherwise require over-dimensioning of components, allowing the gear components to be dimensioned closer to material fatigue limits while maintaining durability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tooth flank profiles are pre-adjusted during manufacturing to compensate for expected load variations and stress distributions. This preliminary optimization of the gear geometry prevents excessive stress concentrations during operation, enabling lighter components to achieve the required durability without exceeding material fatigue limits.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If uniform tooth flank profiles are used across all teeth, then manufacturing process is simplified, but load distribution becomes uneven under varying torque conditions

Engineering Contradiction:
Improvetooth fabrication consistencyVSAvoidtorque distribution uniformity
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent implements different tooth flank profiles for different teeth along the tooth trace, with each tooth's profile specifically adapted to its position and expected load conditions. This localized differentiation ensures uniform load distribution under varying torque conditions while maintaining systematic manufacturing processes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tooth flank profiles are designed to dynamically adapt to varying load conditions through their geometric characteristics. By incorporating position-dependent profile parameters, the gear system can handle varying torque conditions more effectively, distributing loads uniformly across all teeth regardless of operational variations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2554841B1A gearbox comprising a stationary gear component formed on the basis of variable flank profiles of gear teeth
Publication Date: 2015.09.16 VESTAS WIND SYSTEMS AS
  • EP2554841B1 patent drawingFigure 1a
  • EP2554841B1 patent drawingFigure 1b
  • EP2554841B1 patent drawingFigure 1c

AI summary

In a gearbox, a stationary gear component such as a ring gear of a planetary gear comprises a tooth trace correction that varies along the tooth trace so as to provide for superior load distribution in the gearbox. In some illustrative embodiments, the gearbox is a component of a wind power plant wherein the circumferentially varying tooth trace correction of the stationary ring gear results in superior durability and performance.