Three-Point Contact Bearing With Eccentric Drain for Low Power Loss

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Solution Overview

Problem

Bearing designs with radial holes for fluid circulation in turbomachines and electric motors at high speeds often result in power dissipation due to sliding at two points of contact on the outer ring, leading to a near-zero power balance, especially under high radial centrifugal forces.

Innovation Solution

A bearing with three points of contact, featuring an internal and external ring with a drain system in the external track that is eccentrically positioned relative to the rolling plane, allowing fluid circulation and preventing contact between rolling elements and the drain, thus maintaining efficient lubrication and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If radial holes are made for fluid circulation in the bearing, then lubrication and cooling are improved, but power dissipation increases due to sliding at two points of contact on the outer ring

Engineering Contradiction:
Improvecooling efficiencyVSAvoidpower dissipation
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The bearing employs an asymmetric three-point contact configuration where the rolling elements contact the outer ring at only one point in a sector delimited by the proximal end and the rolling plane. This asymmetric arrangement eliminates the second contact point on the outer ring that causes sliding, thereby reducing power dissipation while maintaining fluid circulation through strategically positioned drains that do not interfere with the contact points.

Inventive Principle:
Principle #4Asymmetry

2Object-generated harmful factors

If drilling is centered on the radial plane to ensure fluid circulation, then lubrication is improved, but the bearing requires four points of contact which causes sliding and power dissipation

Engineering Contradiction:
Improvefluid circulationVSAvoidpower dissipation
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The invention extracts the harmful second contact point on the outer ring by repositioning the contact sector to be delimited by the proximal end and the rolling plane. This extraction eliminates the sliding condition while the drain system is strategically positioned to extract and remove fluid from the bearing, maintaining circulation without requiring the harmful four-point contact configuration.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If the bearing operates with two points of contact on the outer ring under high radial centrifugal forces, then structural stability is maintained, but sliding occurs resulting in significant power dissipation

Engineering Contradiction:
Improvestructural stabilityVSAvoidpower balance
Core Design Contradiction:
Stability of the object's compositionVSPower

Solution Approach 1:

The bearing employs an asymmetric three-point contact configuration where the rolling elements contact the outer ring at only one point in a sector delimited by the proximal end and the rolling plane. This asymmetric arrangement eliminates the second contact point on the outer ring that causes sliding, thereby reducing power dissipation while maintaining fluid circulation through strategically positioned drains that do not interfere with the contact points.

Inventive Principle:
Principle #4Asymmetry

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 three-point contact bearing design with an eccentric drain system enhances fluid circulation, reducing power dissipation and maintaining a positive power balance even at high speeds, optimizing lubrication and cooling without the need for additional cooling systems.

Implementation Method 1

circulation of a fluid, typically oil or fuel, in order to ensure lubrication and cooling of the bearings

Methodology Applied
Scientific EffectFluid circulation: Convection

Implementation Method 2

spherical rolling elements, so as to define a rotational movement along a main axis between the inner ring and the outer ring

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP4077958B1Three-point contact rolling bearing with improved drain
Publication Date: 2023.10.11 SAFRAN HELICOPTER ENGINES
  • EP4077958B1 patent drawingFigure 1~2
  • EP4077958B1 patent drawingFigure 3~5
  • EP4077958B1 patent drawingFigure 6~7

AI summary

Three-point contact rolling bearing (1) wherein the internal raceway (12), the third contact point (P3) being situated in a sector of the external raceway (22) delimited by a proximal end of the external raceway (22) on one side, and by the rolling plane (Pr) on the other side, characterized in that the external ring (20) comprises a drain (50) that is provided in the external raceway (22) and opens out at an external surface of the external ring (20), said drain (50) opening onto the external raceway (22) in an off-centre manner with respect to the rolling plane (Pr), in a sector of the external raceway (22) that is delimited by the rolling plane (Pr) on one side, and by a distal end of the external raceway (22) on the other side, the drain (50) and the third contact point (P3) being separated from one another.