Non-Through Shaft Rotor for Larger Conductive Bars and Rigidity

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Solution Overview

Problem

Rotors with non-through shafts for rotating electrical machines face challenges in increasing the section of conductive bars without compromising the compaction of the magnetic mass, leading to reduced critical speed and flexibility issues due to decompaction at the periphery.

Innovation Solution

A rotor design with cylindrical magnetic mass clamped between half-shafts, featuring axial housings and insertion holes that allow for the insertion of conductive bars and coils, with screws and tie rods maintaining compaction, and a fixing flange with chamfers and countersinks to facilitate bar insertion and removal without dismantling, ensuring uniform compaction and increased critical speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the diameter of the fixing flanges is reduced to increase the cross-section of conductive bars, then the cross-section of conductive bars is improved, but the compaction of magnetic mass deteriorates

Engineering Contradiction:
Improvecross-section of conductive barsVSAvoidcompaction of magnetic mass
Core Design Contradiction:
Area of moving objectVSStability of the object's composition

Solution Approach 1:

The rotor is divided into two half-shafts that can be assembled separately. The magnetic mass is segmented into multiple laminations that can be stacked and compacted independently. This segmentation allows conductive bars to be inserted into housings before final assembly, enabling larger bar cross-sections without compromising magnetic mass compaction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a through-shaft design to a non-through shaft design with blind holes in the fixing flanges. This dimensional change allows conductive bars to be inserted axially into housings and secured from the side, enabling larger bar cross-sections while maintaining flange diameter for proper magnetic mass compaction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of moving object

If the fixing flange diameter is reduced to accommodate larger conductive bars, then the conductive bar size is improved, but the critical speed of rotor deteriorates

Engineering Contradiction:
Improvecross-section of conductive barsVSAvoidcritical speed of rotor
Core Design Contradiction:
Area of moving objectVSSpeed

Solution Approach 1:

By segmenting the rotor into two half-shafts with separate assembly, the invention maintains the full diameter of the fixing flanges for proper magnetic mass compaction and rotor rigidity, while still accommodating larger conductive bars through the blind hole insertion method. This preserves the critical speed characteristics.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Conductive bars are preliminarily inserted into housings and secured with retention elements before the final assembly of the rotor. This preliminary action allows for larger bar cross-sections without requiring reduced flange diameter, thereby maintaining rotor rigidity and critical speed.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If conductive bars are inserted into compacted magnetic mass, then the rotor assembly is simplified, but the conductive bars cannot be removed without dismantling tie rods

Engineering Contradiction:
Improverotor assembly complexityVSAvoidconductive bar removal
Core Design Contradiction:
Device complexityVSEase of repair

Solution Approach 1:

The rotor is segmented into two half-shafts that can be separated. The blind holes in the fixing flanges allow conductive bars to be accessed and removed from one side only, eliminating the need to dismantle tie rods or disassemble the entire rotor structure for maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conductive bars are extracted from the magnetic mass and placed in separate housings that are accessible through blind holes in the fixing flanges. This extraction allows bars to be removed independently without affecting the magnetic mass compaction or requiring dismantling of structural components like tie rods.

Inventive Principle:
Principle #2Taking out (Extraction)

4Area of moving object

If the fixing flange diameter is reduced to fit larger conductive bars, then the conductive bar cross-section is improved, but the rotor flexibility increases causing reduced operating speed range

Engineering Contradiction:
Improvecross-section of conductive barsVSAvoidrotor rigidity
Core Design Contradiction:
Area of moving objectVSStability of the object's composition

Solution Approach 1:

The rotor is divided into two half-shafts with separate assembly procedures. This segmentation allows the fixing flanges to maintain their full diameter for proper magnetic mass compaction and rotor rigidity, while conductive bars with larger cross-sections are inserted into housings through blind holes, preventing rotor flexibility issues.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3895294B1Rotor with non-through shaft and associated rotary electric machine
Publication Date: 2024.06.05 GE ENERGY POWER CONVERSION TECHNOLOGY LTD(GB)
  • EP3895294B1 patent drawingFigure 1
  • EP3895294B1 patent drawingFigure 2~3
  • EP3895294B1 patent drawingFigure 4~5

AI summary

The rotor (18) with a non-through shaft for a rotary electric machine comprises a cylindrical magnetic body (19) clamped between two half-shafts (20), each comprising an attachment flange (21) connected to the magnetic body, axial housings (22) being uniformly provided in the magnetic body on at least one diameter (D22) of the magnetic body in order to house conductive bars (25). At least one attachment flange comprises insertion holes (23), each arranged facing a housing for inserting the conductive bars into the housings and the exterior diameter (D21) of the attachment flange is substantially equal to the exterior diameter (D19) of the magnetic body, the attachment flange comprising as many insertion holes (23) as housings.