Propeller Ring Ovoid Radial Housings for Bearing Wear Reduction

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Solution Overview

Problem

Propeller rings in turbomachines with variable-pitch blades face significant wear due to centrifugal and axial loads, leading to rapid deformation and ovalization of bearing rings, which increases friction and reduces the lifespan of these components.

Innovation Solution

The propeller ring features radial housings with a substantially ovoid cross-section, having a minor and major diameter, allowing for deformation compensation under load, thereby maintaining optimal blade pitch and extending the life of bearing parts without altering the ring's size or weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cylindrical housings are used to receive bearings, then the structure is simple and easy to manufacture, but the bearing rings undergo rapid deformation and ovalization under centrifugal and axial loads, leading to increased friction and wear

Engineering Contradiction:

Improvehousing structure simplicityVSAvoidbearing ring stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The housing cross-section is changed from a cylinder to an ovoid shape with a specific ratio between major and minor axes (between 1.05 and 1.2). This curved geometry allows the housing to deform elastically under centrifugal and axial loads in a controlled manner, compensating for the deformation and preventing ovalization of the bearing rings, thus maintaining bearing stability and reducing wear while remaining manufacturable

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the propeller ring diameter is increased to reduce blade pitch variation, then the blade pitch control is improved, but the centrifugal loads on the bearing rings increase, accelerating their wear and deformation

Engineering Contradiction:

Improveblade pitch controlVSAvoidcentrifugal load on bearing rings

Core Design Contradiction:

Adaptability or versatilityVSForce

Solution Approach 1:

The housing cross-sectional geometry is changed from a cylinder to an ovoid shape with specific dimensional ratios (major axis to minor axis between 1.05 and 1.2). This parameter change in the housing geometry allows it to deform elastically under centrifugal loads, compensating for the increased forces and preventing bearing ring ovalization, thus maintaining blade pitch control while reducing wear

Inventive Principle:

Principle #35Parameter changes

3Strength

If bearing rings are sintered to provide support, then the bearing support strength is improved, but the differential deformation under tangential and axial loads causes ovalization at the blade roots, increasing friction and wear

Engineering Contradiction:

Improvebearing support strengthVSAvoidbearing ring wear resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The housing is designed with an ovoid cross-section that allows controlled elastic deformation under centrifugal and axial loads. This curvature enables the housing to compensate for differential deformations and prevent ovalization of the sintered bearing rings at the blade roots, maintaining both strength and wear resistance

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design minimizes bearing part deformations and wear, ensuring prolonged operation and reduced maintenance by adapting to centrifugal and axial loads through an ovoid cross-section that stabilizes the bearing rings, enhancing the overall performance and longevity of the turbomachine.

Implementation Method 1

the radial housings having, in a plane tangential to the annular body, a substantially ovoid cross-section, said substantially ovoid cross-section having a minor diameter and a major diameter whose dimensions are distinct

Methodology Applied

Scientific EffectDeformation compensation: Deformation

Implementation Method 2

allowing for deformation compensation under load, thereby maintaining optimal blade pitch

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10526067B2Propeller ring comprising radial housings with an ovoid cross-section

Publication Date: 2020.01.07 SAFRAN AIRCRAFT ENGINES SAS

AI summary

The invention relates to a propeller ring (10) of a turbomachine (1), with variable-pitch blades (P), the propeller ring (10) comprising a substantially coaxial annular body (11) with a main axis (A) and a plurality of radial housings (12) uniformly distributed around the main axis (A), each radial housing (12) being designed to receive a bearing (13) for a root (14) of a blade (P) so as to allow the variable pitch of the blade (P), the radial housings (12) having a substantially ovoid cross-section in a plane (T) tangential to the annular body (11).