Gearbox Gutter Sizing for Lubricant Scavenging and Windage Loss

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Solution Overview

Problem

Existing gearbox assemblies in gas turbine engines face efficiency losses due to windage and friction, and improper sizing of gutters for lubricant scavenging can lead to reduced efficiency and increased weight, with gutters that are either too large or too small failing to effectively capture and remove lubricant.

Innovation Solution

The implementation of a lubricant extraction volume ratio (LEVR) between 0.01 and 0.3, which optimizes the gutter volume relative to the gearbox volume, ensuring effective lubricant scavenging while minimizing weight and space usage, thereby maintaining gearbox efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gutter volume is increased to improve lubricant scavenging efficiency, then the lubricant collection capability is improved, but the weight and space requirements increase

Engineering Contradiction:

Improvelubricant scavenging efficiencyVSAvoidgutter weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies parameter changes by optimizing the gutter volume to gearbox volume ratio (setting it between 0.05 and 0.2) to achieve the best balance between lubricant scavenging efficiency and weight reduction, rather than simply increasing gutter volume

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the gutter volume is increased to improve lubricant scavenging efficiency, then the lubricant collection capability is improved, but the space requirements increase

Engineering Contradiction:

Improvelubricant scavenging efficiencyVSAvoidgutter volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent optimizes the gutter volume to gearbox volume ratio parameter (setting it between 0.05 and 0.2) to achieve the best balance between lubricant scavenging efficiency and space utilization, rather than simply increasing gutter volume

Inventive Principle:

Principle #35Parameter changes

3Weight of stationary object

If the gutter volume is decreased to reduce weight and space requirements, then the weight and space usage are minimized, but the lubricant scavenging efficiency is reduced

Engineering Contradiction:

Improvegutter weightVSAvoidlubricant scavenging efficiency

Core Design Contradiction:

Weight of stationary objectVSReliability

Solution Approach 1:

The patent determines the optimal gutter volume to gearbox volume ratio (between 0.05 and 0.2) to achieve the best balance between weight reduction and maintaining effective lubricant scavenging, rather than simply decreasing gutter volume

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If improper gutter sizing is used, then the manufacturing and installation are simplified, but the gearbox efficiency is reduced due to windage and friction losses

Engineering Contradiction:

Improvegutter sizing simplicityVSAvoidgearbox efficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent optimizes the gutter volume to gearbox volume ratio (setting it between 0.05 and 0.2) to achieve the best balance between ease of manufacture and minimizing energy losses from windage and friction, rather than using improper sizing

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12326115B2Gearbox assembly with lubricant extraction volume ratio

Publication Date: 2025.06.10 GENERAL ELECTRIC CO

AI summary

A gas turbine engine includes a gearbox assembly that includes a gearbox and a gutter for collecting a gearbox lubricant scavenge flow from the gearbox. The gutter is characterized by a lubricant extraction volume ratio between 0.01 and 0.3, inclusive of the endpoints. The lubricant extraction volume ratio defined by:VGVG⁢B·VGis a gutter volume of the gutter and VGB is a gearbox volume. The gas turbine engine includes a lubricant flow control system that includes a variable flow lubricant pump that generates a pump variable flow of lubricant to the gearbox assembly. The gearbox assembly has a variable consumption demand for delivery of lubricant. A lubricant flow controller is configured to generate a pump control command for the variable flow lubricant pump to produce the pump variable flow of lubricant based on the variable consumption demand.