Rotating Shaft Rectifier Assembly with Keyed Alignment

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Solution Overview

Problem

Existing electric machine systems in aircraft face challenges in efficiently converting alternating current (AC) to direct current (DC) within rotating shafts, leading to potential alignment issues and increased risk of component damage due to heat and vibrations.

Innovation Solution

A rectifier assembly is integrated within a non-conductive sleeve within the rotating shaft, featuring a keyed bus bar system that radially aligns and secures the rectifier subassembly, ensuring proper alignment and electrical insulation, while a thermally insulating gap prevents heat-induced damage to the shaft tube.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rectifier assembly is mounted inside a rotating shaft without proper alignment features, then assembly is simpler, but alignment issues occur leading to component damage

Engineering Contradiction:
Improveassembly simplicityVSAvoidalignment accuracy
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs asymmetric keyways and corresponding keys on the rectifier assembly components. The keyway in the brush holder assembly and the key on the rectifier bridge assembly are positioned at specific asymmetric locations that ensure proper radial alignment when assembled. This asymmetric feature prevents misalignment while maintaining straightforward assembly procedures.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces a key as an intermediary element between the rectifier bridge assembly and the brush holder assembly. This key acts as a mediator that transfers and maintains the correct radial alignment relationship between the two components during assembly and operation, preventing alignment issues without complicating the overall assembly process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the rectifier assembly is securely fixed within the shaft, then reliability improves, but assembly time increases

Engineering Contradiction:
Improvecomponent securityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent incorporates pre-designed keyways and keys that are integrated into the rectifier assembly components before final installation. The key is already positioned on the rectifier bridge assembly, and the keyway is pre-formed in the brush holder assembly, allowing for quick and secure assembly without requiring additional alignment or securing steps during installation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent combines the alignment and securing functions into a single key-keyway interface. This integrated approach eliminates the need for separate alignment features and securing mechanisms, achieving both reliable component fixation and rapid assembly in one straightforward operation.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If thermal insulation measures are added to protect the shaft tube, then component damage from heat is reduced, but device complexity increases

Engineering Contradiction:
Improveheat protectionVSAvoidassembly complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the thermal insulation function from the overall shaft structure and implements it through a dedicated insulating barrier layer within the rectifier assembly. This separate insulating layer is positioned between the rectifier components and the shaft tube, providing heat protection without requiring complex modifications to the shaft structure itself.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies thermal insulation locally at the critical interface between the rectifier assembly and the shaft tube. The insulating barrier is positioned specifically where heat transfer is most problematic, providing targeted heat protection without adding insulation throughout the entire shaft assembly, thereby maintaining simplicity.

Inventive Principle:
Principle #3Local quality

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 configuration enables efficient AC to DC conversion with reduced maintenance downtime, weight, and size, minimizing the risk of component failure and allowing high-speed rotation with improved reliability and reduced assembly time.

Implementation Method 1

a non-conductive sleeve having an outer surface and an inner surface defining an interior having a keyway

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

the rectifier subassembly is configured to convert the alternating current output to the direct current input

Methodology Applied
Scientific EffectRectification: Diode

Implementation Method 3

a thermally insulating gap prevents heat-induced damage to the shaft tube

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2940840B1Rotating rectifier assembly for electric machine
Publication Date: 2017.07.12 GE AVIATION SYSTEMS LLC
  • EP2940840B1 patent drawingFigure 1
  • EP2940840B1 patent drawingFigure 2
  • EP2940840B1 patent drawingFigure 3

AI summary

An electric machine (10) having a rectifier assembly (27) placed within a rotating shaft (24) of the electric machine to convert the AC output of the electric machine to the DC input prior to transmission of the electricity from the electric machine.