Rotorcraft Gearbox Lubrication Flow Control

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Solution Overview

Problem

Rotorcrafts face operational challenges due to reduced lubricant pressure, leading to excessive wear and potential failure of gearbox components, as existing secondary lubrication systems may not conserve lubricant sufficiently or adapt flow rates effectively to maintain manageable flight operations.

Innovation Solution

A lubrication flow calculation unit determines the flow rate of lubricant to a gearbox based on rotorcraft parameters, such as rotational speed and temperature, to optimize lubricant delivery and reduce friction, using a secondary lubrication system that adjusts flow rates dynamically to extend operational time during low lubricant pressure conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a secondary lubrication system with injectable additive is used, then the operational time period of the gearbox during oil-out condition is increased, but the lubricant pressure delivery capability is insufficient

Engineering Contradiction:
Improveoperational time periodVSAvoidlubricant pressure
Core Design Contradiction:
Duration of action of moving objectVSStress or pressure

Solution Approach 1:

The system dynamically adjusts lubricant flow rate based on real-time monitoring of lubricant pressure and temperature conditions. The flow rate is increased when pressure drops below a threshold and decreased when pressure is normal, creating a responsive adaptive system that optimizes both pressure delivery and operational duration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the flow rate parameter of lubricant delivery based on detected pressure and temperature conditions. By adjusting this parameter dynamically, the system resolves the contradiction between maintaining adequate pressure and extending operational time during oil-out conditions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If lubricant flow rate is increased to maintain pressure, then friction reduction is improved, but lubricant consumption increases

Engineering Contradiction:
Improvefriction reductionVSAvoidlubricant consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The system adjusts the flow rate parameter dynamically based on actual pressure and temperature conditions. Flow rate is increased only when pressure drops below a threshold, providing adequate lubrication for friction reduction, and decreased when pressure is normal, thereby conserving lubricant and resolving the contradiction between reliability and substance loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses feedback from pressure and temperature sensors to continuously monitor gearbox conditions and adjust flow rate accordingly. This closed-loop control ensures lubricant is delivered at optimal rates to maintain friction reduction while minimizing unnecessary consumption.

Inventive Principle:
Principle #23Feedback

3Device complexity

If a fixed flow rate system is used, then the system complexity is reduced, but the adaptability to different operating conditions deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidadaptability to operating conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transitions from a fixed flow rate to a dynamic adjustable flow rate system. A control mechanism responds to pressure and temperature sensor inputs, automatically adjusting the flow rate to match actual gearbox conditions, thereby achieving adaptability without excessive complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system monitors its own operating conditions through sensors and automatically adjusts lubricant flow rate without external intervention. This self-regulating capability provides adaptability to different operating conditions while maintaining relatively simple system architecture.

Inventive Principle:
Principle #25Self-service

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 enables rotorcrafts to operate safely for longer durations with reduced lubricant pressure by optimizing lubricant flow, reducing friction, and conserving lubricant, thus preventing excessive waste and component wear.

Implementation Method 1

A rotorcraft may include one or more rotor systems. One example of a rotorcraft rotor system is a main rotor system. A main rotor system may generate aerodynamic lift to support the weight of the rotorcraft in flight, and thrust to counteract aerodynamic drag and move the rotorcraft in forward flight.

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP3085998B1Method for the delivery of lubricant to a rotorcraft gearbox
Publication Date: 2017.08.09 BELL HELICOPTER TEXTRON INC
  • EP3085998B1 patent drawingFigure 1~2
  • EP3085998B1 patent drawingFigure 3
  • EP3085998B1 patent drawingFigure 4

AI summary

According to one embodiment, a rotorcraft (100) includes a body (130), a rotor blade (120), and a power train (110) coupled to the body (130) and operable to rotate the rotor blade (120). The power train (110) includes an engine (112), a gearbox (160) in mechanical communication with the engine (112), and a driveshaft (116) in mechanical communication with the gearbox (160). The rotorcraft (100) also includes a sensor (410) operable to detect a rotorcraft parameter (415), and a lubrication flow calculation unit (420) operable to receive the rotorcraft parameter (415), generate the flow rate (425) based on the rotorcraft parameter (415), and transmit the flow rate (425) to a lubrication system (200, 430) configured to deliver lubricant to the gearbox (160) at the transmitted flow rate (425).