Freewheel Lubrication Barrier With Variable Opening for Heat Control

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Solution Overview

Problem

Existing freewheel lubrication systems face challenges in maintaining effective lubrication during both engaged and disengaged operating modes, with current methods either failing to immerse contact zones adequately during engagement or causing heating issues due to bubbling during disengagement.

Innovation Solution

A freewheel with a lubrication barrier featuring a variable opening mechanism, where the opening area adjusts based on the position of the cage relative to the driving part, allowing for optimal lubrication during engagement and efficient fluid evacuation during disengagement, ensuring consistent lubrication and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact areas are immersed in an oil bath during engaged operation, then wear on the freewheel is limited, but during disengaged operation the oil generates heat through a splashing effect

Engineering Contradiction:
Improvewear protectionVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The barrier is designed to be movable relative to the driving part, changing its position between engaged and disengaged operating modes. During engaged mode, the barrier closes to immerse contact areas in lubricating fluid for wear protection. During disengaged mode, the barrier opens to allow oil evacuation and prevent splashing-induced heating. This dynamic reconfiguration resolves the contradiction between wear protection and heat generation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of lubricating fluid volume in the connecting space based on operating mode. During engaged operation, the barrier closes to maintain high lubricant volume for adequate immersion of contact areas. During disengaged operation, the barrier opens to reduce lubricant volume and eliminate the oil bath, thereby preventing heat generation from splashing while maintaining lubrication when needed.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a rim is used to delimit a lubricant pool containing the rollers, then contact areas are immersed in oil during engaged operation, but the rim must be precisely sized to prevent splashing during disengaged operation

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidrim sizing precision
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of a fixed rim that requires precise sizing, the invention uses a movable barrier that actively opens during disengaged operation. This dynamic mechanism eliminates the need for precise rim dimensioning, as the barrier completely opens to allow unrestricted oil evacuation, simplifying the design while maintaining lubrication effectiveness during engaged mode.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a barrier completely blocks fluidic communication to flood contact areas during engaged operation, then lubrication is improved, but fluid evacuation during disengaged operation becomes difficult

Engineering Contradiction:
Improvelubrication coverageVSAvoidfluid evacuation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The barrier is designed with movable elements that change its blocking capability based on operating mode. During engaged operation, the barrier closes completely to flood contact areas with lubricating fluid for optimal lubrication coverage. During disengaged operation, the barrier opens to restore fluidic communication, enabling efficient oil evacuation. This dynamic behavior resolves the contradiction between lubrication coverage and fluid evacuation efficiency.

Inventive Principle:
Principle #15Dynamics

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 ensures thorough lubrication of freewheel components during engaged mode while preventing overheating by maximizing fluid evacuation during disengaged mode, thereby extending freewheel lifespan and performance.

Implementation Method 1

a lubricating fluid circulating during engaged operation to lubricate the contact areas

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

This internal shaft then has at least one radial orifice to direct the oil between the driving and driven sections by centrifugal force

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

The lubrication system then aims to dissipate heat to cool the freewheel

Methodology Applied
Scientific EffectHeat dissipation: Convection

Data Source

PatentEP4012213B1Free wheel provided with a lubrication barrier with variable opening
Publication Date: 2023.07.12 EUROCOPTER FRANCE SA
  • EP4012213B1 patent drawingFigure 1~2
  • EP4012213B1 patent drawingFigure 3~4
  • EP4012213B1 patent drawingFigure 5~6

AI summary

The present invention relates to a freewheel (10) comprising a driving portion (20) and a driven portion (30) that are free to rotate about an axis of rotation (AX). The freewheel (10) comprises a cage (400) carrying at least one rolling element (40) arranged in a connecting space (50). The freewheel (10) has at least one lubrication device (80) conveying a lubricating fluid (85) into the connecting space (50). The freewheel (10) includes at least one barrier (70) with a variable opening, arranged radially between the driving portion (20) and the driven portion (30) and longitudinally against the connecting space (50). The opening is indexed to a relative position of the cage (400) and the driving portion (20).