Rotor Hub Bearing System with Segmented Elastomeric Layers

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Solution Overview

Problem

Existing rotor hub bearing systems are constrained by the need to be sized for the most severe dynamic motion, limiting their ability to be tailored for specific dynamic motions such as flapping, lead/lag, and torsional motions, resulting in inefficient size and structural requirements.

Innovation Solution

A bearing system with an outer member having alternating elastomeric and shim layers, and an inner member with cone or journal shaped elastomeric and shim layers, allowing for tailored stiffness and reduced size by combining torsional stiffness contributions from both members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the bearing is sized for the most severe dynamic motion, then it can handle all flapping motions, lead/lag motions, and torsional motions, but the bearing size cannot be specifically tailored for more than one dynamic motion

Engineering Contradiction:

Improvecapability to handle multiple dynamic motionsVSAvoidbearing size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The bearing is divided into an outer member and an inner member, each capable of independently reacting to different dynamic motions. The outer member primarily handles flapping and lead/lag motions, while the inner member handles torsional motions, allowing the bearing to be tailored for specific dynamic motions while maintaining versatility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the bearing are given different stiffness characteristics. The outer member is designed with specific stiffness properties for certain motions, while the inner member has different stiffness properties for other motions, enabling the bearing to be optimized for multiple dynamic motions simultaneously

Inventive Principle:

Principle #3Local quality

2Reliability

If the outer member has a stiffness for treating all dynamic motions, then it can react all flapping motions, lead/lag motions, and torsional motions, but the bearing cannot be specifically tailored for more than one dynamic motion

Engineering Contradiction:

Improvecapability to react all dynamic motionsVSAvoidtailorability for specific dynamic motions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The bearing is segmented into outer and inner members with different stiffness characteristics. The outer member is optimized for flapping and lead/lag motions, while the inner member is optimized for torsional motions, allowing each member to be specifically tailored for its intended dynamic motion while collectively providing comprehensive motion reaction capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the bearing (outer member vs. inner member) are assigned different stiffness qualities appropriate for different dynamic motions. This allows the bearing to maintain reliability for all motions while being adaptable and tailorable for specific motion types

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the bearing is designed with alternating elastomeric and shim layers, then it can provide tailored stiffness, but the structural requirements and steady torsional loading increase

Engineering Contradiction:

Improvetailored stiffnessVSAvoidstructural requirements

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The bearing is divided into outer and inner members that share the load-bearing function. The elastomeric and shim layers are distributed between both members, allowing the tailored stiffness to be achieved while distributing structural requirements and reducing steady torsional loading on any single component

Inventive Principle:

Principle #1Segmentation

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 reduces the overall size of the bearing, increases geometric efficiency, and provides tailored torsional compliance, reducing structural requirements and steady torsional loading.

Implementation Method 1

an outer member having alternating elastomeric and shim layers, and an inner member with cone or journal shaped elastomeric and shim layers

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

A bearing system with an outer member having alternating elastomeric and shim layers, and an inner member with cone or journal shaped elastomeric and shim layers, allowing for tailored stiffness

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Data Source

PatentUS10532809B2Rotor hub bearing system

Publication Date: 2020.01.14 TEXTRON INNOVATIONS INC

AI summary

The bearing system is configured for treating and reacting dynamic loading within a rotor hub of rotorcraft. The bearing system includes an outer member having a plurality of alternating outer elastomeric layers and shim layers. The outer member has an inboard surface configured for bonding to an inboard bearing support, and the outer member has an outboard surface configured for bonding to an outboard bearing support. The bearing system has an inner member bonded to an interior surface of the outer member. The inner member can include a rigid inner core, as well as a plurality of elastomeric layers and shim layers configured to react torsional movements of the rotor blade.