Helicopter Flexbeam Hinge Eliminates Bearing Wear

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Helicopter rotor blade bearings experience high wear rates and require frequent lubrication due to sliding contact, leading to increased maintenance costs and frictional moments that hinder high-frequency pitching control.

Innovation Solution

A flexbeam system made of fiber/epoxy composites is used to retain and pitch the trailing edge flap, eliminating sliding contacts and friction, while being flexible about the pitching axis to control rotor blade pitch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ball or spherical bearings are used to support the rotating shaft for active trailing edge flap control, then the flap can be actuated multiple times per revolution, but the bearings exhibit large wear rates and require constant lubrication

Engineering Contradiction:

Improveflap actuation frequencyVSAvoidbearing wear rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces traditional ball or spherical bearings with a magnetic bearing system that uses magnetic fields to support the rotating shaft. This substitution eliminates sliding contact between mechanical components, thereby eliminating wear and the need for lubrication while maintaining the capability for multiple flap actuations per revolution

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic fields as an intermediary between the rotating shaft and the stationary structure. The magnetic bearing system uses magnetic attraction and repulsion forces to support the shaft without physical contact, serving as a non-mechanical mediator that eliminates direct mechanical wear

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If ball or spherical bearings are used to support the rotating shaft, then the flap can be actively controlled, but frictional moments must be overcome by pitch control systems

Engineering Contradiction:

Improveactive flap controlVSAvoidfrictional moments

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent replaces mechanical bearings with a magnetic bearing system that supports the rotating shaft through magnetic fields. This eliminates sliding friction between mechanical components, removing frictional moments that would otherwise require additional force from pitch control systems to overcome

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If bearings with sliding contact are used, then the rotor blade can rotate and control the flap, but lubrication is required constantly

Engineering Contradiction:

Improverotor blade rotationVSAvoidlubrication maintenance

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent replaces sliding contact bearings with a magnetic bearing system that supports the rotating shaft without physical contact. This eliminates the need for lubrication while maintaining the rotor blade's rotation capability and flap control functionality

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 flexbeam system reduces wear, eliminates the need for lubrication, and minimizes friction, resulting in lower maintenance costs and improved rotor blade control with potentially unlimited fatigue life.

Implementation Method 1

a flexbeam body extending from the first end to the second end and being configured to retain the flap under a first loading and being flexible about the pitching axis

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS9428268B2Flexbeam hinge for helicopter blade active trailing edge flap

Publication Date: 2016.08.30 SIKORSKY AIRCRAFT CORP

AI summary

A flexbeam for a rotor blade is provided and includes a first end coupled to a body of the rotor blade and a second end coupled to a flap disposed along a trailing edge of the body to pitch about a pitching axis defined along a span of the body and a flexbeam body extending from the first end to the second end and being configured to retain the flap under a first loading and being flexible about the pitching axis.