Aircraft Gearbox Lubrication with Shared Reservoir Backup Flow

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Solution Overview

Problem

Current aircraft lubrication systems face challenges during loss of lubrication events, where the separate emergency lubrication system remains inactive until an event is identified, leading to gear damage and increased complexity and cost, as well as the need for continuous heating of the emergency lubricant reservoir.

Innovation Solution

A lubrication system with a common lubricant reservoir that is continuously refilled and shared by both primary and secondary pumping elements, allowing both elements to operate continuously, providing lubricant to the gearbox during normal operation and loss of lubrication events without the need for switching systems or heating the emergency lubricant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate emergency lubrication system is used, then the gearbox can operate during loss of lubrication events, but the system complexity and cost increase

Engineering Contradiction:
Improvegearbox operation during loss of lubricationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the primary and emergency lubrication systems into a single integrated system. The primary pump and emergency pump share a common lubricant reservoir and can both pump lubricant to the gearbox simultaneously or independently. This eliminates the need for separate emergency lubrication infrastructure while maintaining the capability to operate during loss of lubrication events.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The primary pump is designed to serve dual functions: acting as the primary lubrication source during normal operation and as a backup emergency pump when the emergency pump fails. This multi-functionality reduces the need for completely separate systems while ensuring reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a separate emergency lubrication system is used, then the gearbox can operate during loss of lubrication events, but the cost increases

Engineering Contradiction:
Improvegearbox operation during loss of lubricationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the primary and emergency lubrication systems into a single integrated system, sharing common components such as the lubricant reservoir, piping, and gearbox interface. This merging reduces the total number of components that need to be manufactured and assembled, thereby reducing overall system cost while maintaining emergency operation capability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the emergency lubricant reservoir is kept separate, then the emergency system can be activated independently, but continuous heating is required

Engineering Contradiction:
Improveemergency system activationVSAvoidenergy for heating
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges the primary and emergency lubricant storage into a single common reservoir. Both the primary pump and emergency pump draw lubricant from this shared reservoir. Since the lubricant is continuously circulated through the gearbox during normal operation, it remains at operational temperature without requiring separate heating systems for the emergency reservoir.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The lubricant is pre-heated and circulated through the gearbox during normal operation, so when an emergency occurs, the lubricant is already at the correct temperature and ready for immediate use by the emergency pump, eliminating the need for separate heating infrastructure.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the emergency pump is separate from the primary pump, then the emergency system can operate independently, but the system complexity increases

Engineering Contradiction:
Improveindependent emergency operationVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the emergency pump into the primary lubrication system infrastructure. Both pumps share the same lubricant reservoir, piping network, and gearbox interface. This shared infrastructure reduces complexity while maintaining the ability for independent operation during emergencies.

Inventive Principle:
Principle #5Merging (Combining)

5Reliability

If switching systems are used to activate emergency lubrication, then the emergency system can be activated during loss of lubrication events, but the response time is delayed

Engineering Contradiction:
Improveemergency lubrication activationVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The emergency pump operates continuously alongside the primary pump during normal operation, just pumping lubricant to the gearbox. When a loss of lubrication event occurs, the emergency pump is already active and continues to provide lubrication immediately without requiring activation or switching. This continuous operation eliminates response time delays.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The emergency pump is pre-positioned and pre-configured within the lubrication system, with all connections and pathways already established. When needed, it can immediately begin pumping without requiring activation sequences, switching operations, or system reconfiguration.

Inventive Principle:
Principle #10Preliminary action

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

This solution reduces complexity and cost, eliminates the need for identifying loss of lubrication events and switching systems, and ensures sustained gearbox operation during emergencies by continuously providing lubricant from interconnected reservoirs, thereby extending gearbox life and preventing torque loss.

Implementation Method 1

a rotor blade coupled to a drive system. The drive system can be operated to rotate the rotor blade about a rotor axis. The lubrication system includes a reservoir, a centrifugal pump

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a centrifugal pump in fluid communication with the at least one gearbox. The centrifugal pump is configured to pump the lubricant from the reservoir to the at least one gearbox

Methodology Applied
Scientific EffectCentrifugal pumping: Centrifugal Force

Data Source

PatentEP3514406B1Aircraft lubrication system
Publication Date: 2022.03.09 TEXTRON INNOVATIONS INC
  • EP3514406B1 patent drawingFigure 1A~1B
  • EP3514406B1 patent drawingFigure 2
  • EP3514406B1 patent drawingFigure 3

AI summary

A system (300) is provided in one example embodiment and may include a first reservoir (312, 612, 712, 812, 912, 1012) for a lubricant (317); a second reservoir (314, 614, 714, 814, 914, 1014) for the lubricant (317), wherein the first reservoir (312, 612, 712, 812, 912, 1012) and the second reservoir (314, 614, 714, 814, 914, 1014) are interconnected; a first pumping element (304) to pump the lubricant (317) from the first reservoir (312, 612, 712, 812, 912, 1012) at a first flow rate; a second pumping element (306) to pump the lubricant (317) at a second flow rate, wherein the first flow rate and the second flow rate are different; and a gearbox (308) coupled to the first pumping element (304) and the second pumping element (306). The first reservoir (312, 612, 712, 812, 912, 1012) may have a larger volume than the second reservoir (314, 614, 714, 814, 914, 1014) and the first flow rate may be higher than the second flow rate.