Wound-Type Rotor Guide Head Support Design

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Solution Overview

Problem

High-speed wound-rotor synchronous electric machines face challenges with complex and weighty radial retention systems for guide heads, which are subject to high centrifugal forces, requiring numerous parts and assembly operations, and additional balancing devices that increase weight and complexity.

Innovation Solution

A guide head support is inserted between the stack of laminations and each guide head, fixed by shrink fitting on the rotor shaft, eliminating the need for crowns, tie rods, and nuts, and allowing for direct radial abutment and balancing via integrated cavities and protruding surfaces for weight addition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If crowns, tie rods, and nuts are used to retain guide heads radially, then the guide heads are securely fixed against centrifugal forces, but the number of parts and assembly operations increases significantly

Engineering Contradiction:
Improveradial retention of guide headsVSAvoidnumber of parts and assembly operations
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide head support merges multiple functions into a single integrated component: it provides radial retention for guide heads through its peripheral surface, structural support through the annular body, and mounting to the rotor shaft through shrink fitting. This eliminates the need for separate crowns, tie rods, and nuts, reducing part count while maintaining secure radial retention against centrifugal forces.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention replaces the mechanical fastening system (crowns, tie rods, nuts requiring screwing operations) with a shrink fitting system. The guide head support is shrunk onto the rotor shaft, creating a secure mechanical connection without requiring threaded fasteners, thereby eliminating complex assembly operations while maintaining reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If a balancing ring with cavities is added to the crown, then rotor balancing is achieved, but the weight and complexity of the device increase

Engineering Contradiction:
Improve rotor balancingVSAvoidweight of balancing device
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The balancing cavities are integrated directly into the guide head support structure rather than being part of a separate balancing ring. This merging of functions allows the same component to provide both structural support and balancing capability, eliminating the need for an additional balancing ring and reducing overall device weight while maintaining rotor balancing stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The balancing function is extracted from a separate balancing ring and integrated into the guide head support itself. The cavities are formed as integral features of the guide head support, allowing balancing masses to be positioned directly where needed without requiring an additional component, thereby reducing weight while achieving the same balancing effect.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If multiple separate components are used for guide head retention, then assembly and disassembly operations increase, but the structural integrity is maintained

Engineering Contradiction:
Improvestructural integrity of rotor assemblyVSAvoidassembly and disassembly efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The guide head support combines multiple structural functions into a single component that maintains rotor assembly integrity: it provides radial retention for guide heads, structural support through its annular body with ribs, and mounting connection to the rotor shaft via shrink fitting. This integration maintains strength while eliminating multiple assembly and disassembly operations, improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies assembly, reduces weight, and enhances radial force resistance without the need for additional balancing rings, improving the rotor's structural integrity and operational efficiency.

Implementation Method 1

said guide head support being fixed by shrink fitting on the rotor shaft

Methodology Applied
Scientific EffectShrink fitting: Thermal Expansion

Data Source

PatentEP3776814B1Wound-type rotor for a synchronous electric machine
Publication Date: 2023.08.16 RENAULT SA
  • EP3776814B1 patent drawingFigure 1~2

AI summary

The invention relates to a rotor comprising an assembly of laminations (2) including a plurality of radially-projecting poles (20), a winding of electrically conductive wires being intended to be wound around each pole by means of wire-guiding heads (3) arranged axially on either side of the lamination assembly. According to the invention, a guiding head support (4) is inserted between the lamination assembly and each guiding head such that: an internal radial face (41) of the support abuts against an external radial face at an axial end of the lamination assembly; and a peripheral surface (42) of the support, which projects axially outward from the internal radial face of said support, is in contact with a contact face (33) of the guiding head that is orientated radially outward from same, the guiding head abutting against the peripheral surface (42) of the support.