Drive Shaft Spline Lubrication Insert With Elastic Reservoir Discharge

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Solution Overview

Problem

Current lubrication systems, particularly single-shot systems, are inadequate in providing sufficient lubrication to the centerline of an accessory drive shaft and other splines further away, leading to suboptimal functionality and reduced lifespan of moving parts in relay boxes.

Innovation Solution

A lubrication system featuring an elastically deformable outer insert wall and a rigid internal insert wall, with a nozzle that delivers fluid to the splines during rotation and expands to increase fluid volume, ensuring effective lubrication to the central axis and additional splines, even when the drive shaft is stationary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a one-shot lubrication system is used, then the system is simple and easy to operate, but it cannot provide adequate lubrication to the central axis and distant splines of the drive shaft

Engineering Contradiction:
Improveamount of lubricant suppliedVSAvoidsystem structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The insert is positioned inside the drive shaft, with the reservoir nested within the insert structure. The elastically deformable outer insert wall portion contains a rigid inner insert wall portion, creating a nested configuration that maximizes lubricant storage within the constrained space of the drive shaft interior.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The outer insert wall portion is made elastically deformable to dynamically expand and contract based on pressure differential. During rotation, centrifugal force and pressure differential cause the insert to expand, increasing lubricant storage capacity and delivery capability to distant splines and central axis areas.

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If the insert expands to increase fluid volume, then more lubricant can be supplied to distant splines, but the insert structure becomes more complex

Engineering Contradiction:
Improvefluid volumeVSAvoidinsert structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The outer insert wall portion is constructed from an elastomeric material that forms a flexible shell capable of elastic deformation. This flexible wall expands under pressure to increase the internal volume of the reservoir, allowing greater lubricant storage and delivery capability without requiring a complex mechanical expansion mechanism.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If a nozzle delivers fluid during rotation, then lubrication is provided during operation, but insufficient lubrication reaches the central axis when stationary

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidlubrication coverage
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A conduit extends through the rigid inner insert wall portion to deliver lubricant directly to the central axis of the drive shaft. This hydraulic pathway ensures that lubricant reaches the central axis and distant splines regardless of rotation state, providing reliable lubrication during both operation and stationary periods.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 system enhances lubricant distribution, improving the operational efficiency and longevity of moving parts by delivering a directed jet of fluid to the splines, including those further away from the drive shaft, thereby addressing the limitations of existing systems.

Implementation Method 1

the elastically deformable outer insert wall portion comprises an elastomeric material

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the nozzle is configured to direct the jet of fluid through the interface and past the weir to the splines when rotation of the drive shaft is stopped

Methodology Applied
Scientific EffectFluid jet: Jet

Data Source

PatentEP3922815B1Lubrication system for supplying a fluid to the splines of a drive shaft
Publication Date: 2024.02.14 AERO GEARBOX INT
  • EP3922815B1 patent drawingFigure 1~2
  • EP3922815B1 patent drawingFigure 3~4
  • EP3922815B1 patent drawingFigure 5A~5B

AI summary

An insert (20) for supplying fluid (15) to a drive shaft (100), the insert (20) extending along an axis of rotation (AR) and comprising an insert wall (26) having a rigid inner insert wall portion (36) and an elastically deformable outer insert wall portion (34), a reservoir (28) defined by the insert wall (26) for storing fluid (15), a nozzle (50) positioned at the first end (22) of the insert wall (26) and wherein the elastically deformable outer insert wall portion (34) is configured to move between an expanded state when fluid (15) is supplied to the reservoir (28) and a non-expanded state when the rotation of the insert (20) and the supply of fluid (15) to the reservoir (28) are stopped, and the movement of the portion elastically deformable external insert wall (34) in the unexpanded state forces the fluid (15) to be discharged through the nozzle (50).