Planetary Gearbox Flow Guidance Device for Lubricant Management

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Solution Overview

Problem

Planetary gear boxes in gas turbine engines face challenges in efficient lubrication, leading to oil ageing and increased maintenance needs due to numerous tooth flank contacts and lack of effective lubricant distribution.

Innovation Solution

A flow guidance device is introduced to manage the planet gear lubricant stream, featuring a collecting region with an outlet region and a sharp edge to reduce oil loss and ageing, ensuring efficient lubrication by capturing and directing the lubricant stream effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional lubrication system is used in planetary gear boxes, then the gear box can operate with basic lubrication, but oil ageing occurs and maintenance needs increase due to numerous tooth flank contacts and lack of effective lubricant distribution

Engineering Contradiction:

Improveservice life of gear boxVSAvoidoil ageing and loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by directing the lubricant stream onto the planet gear before the oil would naturally be carried away by rotation. The flow guidance device captures the lubricant stream at its origin and directs it through the outlet region onto the tooth flanks, ensuring lubrication occurs before oil loss can happen. This preemptive approach to lubricant distribution resolves the contradiction between maintaining reliable operation and preventing oil ageing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The flow guidance device acts as an intermediary between the lubricant supply and the gear teeth. It captures the planet gear lubricant stream and mediates its distribution by directing it onto the tooth flanks through the outlet region. This intermediary structure enables controlled lubricant delivery, improving reliability while reducing unnecessary oil loss and ageing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If the flow cross-section of the outlet region is made larger to improve lubricant supply, then more lubricant can be delivered, but the proportion of lubricant carried along by planet gear rotation increases leading to crushing losses on ring gear

Engineering Contradiction:

Improvelubricant supplyVSAvoidcrushing losses of oil on ring gear

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating a localized, controlled lubricant delivery system. The outlet region has a specific flow cross-section (0.5-4 mm) that is optimized to deliver lubricant precisely where needed on the tooth flanks. This localized approach ensures sufficient lubricant supply to contact areas while preventing excess oil from being carried away and causing crushing losses on the ring gear, thus resolving the contradiction between quantity of lubricant and energy loss.

Inventive Principle:

Principle #3Local quality

3Productivity

If the main flow direction of the planet gear lubricant stream is precisely aligned with the outlet region, then lubricant capture efficiency is maximized, but geometric alignment accuracy cannot always be achieved with deviations of +/−20°

Engineering Contradiction:

Improvelubricant capture efficiencyVSAvoidalignment accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies equipotentiality by designing the flow guidance device and outlet region geometry to create a lubricant capture system that is tolerant of alignment variations. The collecting region and outlet configuration are designed so that even with flow direction deviations of +/−20° from exact linear geometric orientation, the lubricant stream remains effectively captured and directed onto the tooth flanks. This design equalizes the performance across a range of alignment conditions, resolving the contradiction between capture efficiency and manufacturing precision.

Inventive Principle:

Principle #12Equipotentiality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances lubricant distribution, reducing oil ageing and maintenance needs, while minimizing oil usage and secondary losses, thereby extending the service life of the gear box.

Implementation Method 1

a planet gear lubricant stream which forms in the planetary gear box and extends along the tooth surfaces and/or the periphery of a planet gear

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11867127B2Planetary gearbox

Publication Date: 2024.01.09 ROLLS ROYCE DEUT LTD & CO KG

AI summary

The invention concerns a planetary gear box with a flow guidance device for a planet gear lubricant stream in the planetary gear box, which is directed at least partially along a planet gear after an engagement with a sun gear, characterized by a collecting region of the flow guidance device in which the planet gear lubricant stream between the planet gear and the flow guidance device can be at least partially captured, and wherein the collecting region has an outlet region between the flow guidance device and the tooth face of the planet gear for at least a part of the planet gear lubricant stream, and an edge is arranged at the outlet region for defined constriction of the passage for the planet gear lubricant stream.