Halbach Rotor Assembly With Sealed Magnet Gaps

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Solution Overview

Problem

Existing rotors for rotary electric machines face challenges in simplifying the assembly of permanent magnets while ensuring protection against atmospheric agents, which can lead to oxidation and compromise the magnetic field integrity.

Innovation Solution

The rotor design incorporates a Halbach array of permanent magnets arranged to nullify the magnetic field radially inward and maximize it outward, with a support cylinder and end discs providing a non-zero axial distance for easy magnet insertion and protection, using a filler to seal gaps and prevent oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If permanent magnets are placed directly on the outer surface of the support cylinder with end discs in axial contact, then the protection against atmospheric agents is improved, but the assembly complexity increases and manufacturing difficulty rises

Engineering Contradiction:
Improveprotection against atmospheric agentsVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a radial dimension (gap between end disc and support cylinder outer surface) to solve the protection problem, rather than relying solely on axial arrangement. This radial gap allows filler material to be introduced, providing protection without requiring complex axial stacking arrangements.

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

Solution Approach 2:

A filler material is introduced as an intermediary substance between the permanent magnets and the atmospheric environment. This filler occupies the radial gap and provides protection against atmospheric agents, simplifying the overall assembly structure while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If permanent magnets are arranged with axial orientation on the support cylinder outer surface, then the magnetic field performance is improved, but the risk of oxidation from atmospheric agents increases

Engineering Contradiction:
Improvemagnetic field performanceVSAvoidoxidation risk
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The filler material serves as an intermediary barrier between the axially oriented permanent magnets and atmospheric agents. It fills the radial gap to prevent oxidation while maintaining the axial orientation configuration that delivers superior magnetic field performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The filler material acts as a sacrificial protective layer that can be easily applied and replaced if needed, providing economical protection against oxidation for the expensive permanent magnets while allowing them to maintain their optimal axial orientation for magnetic performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If a radial gap is introduced between the end disc and support cylinder outer surface, then the protection of permanent magnets is improved through filler material, but the device complexity increases

Engineering Contradiction:
Improveprotection of permanent magnetsVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the radial dimension to create a protective gap that can be filled with protective material. This approach to protection is simpler than complex axial arrangements or coatings, as it uses the existing radial space between components rather than adding separate protective structures.

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

Solution Approach 2:

The radial gap structure serves multiple functions: it provides space for filler material to protect permanent magnets, maintains the structural integrity of the rotor, and allows for thermal expansion. This multi-functionality reduces the need for additional separate protective components, thereby reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design simplifies magnet assembly, reduces oxidation risk, and maintains magnetic field strength by ensuring easy magnet placement and protection, facilitating efficient operation and manufacturing.

Implementation Method 1

The rotor design incorporates a Halbach array of permanent magnets arranged to nullify the magnetic field radially inward and maximize it outward

Methodology Applied
Scientific EffectHalbach Array: Halbach Array

Data Source

PatentEP4465495B1Rotor for a rotary electric machine
Publication Date: 2026.03.25 FERRARI SPA
  • EP4465495B1 patent drawingFigure 1
  • EP4465495B1 patent drawingFigure 2
  • EP4465495B1 patent drawingFigure 3

AI summary

A rotor (4) for a rotary electric machine (1) and having: a support cylinder (8), which has an outer surface (9) and a central cavity (12); a plurality of permanent magnets (6), which are axially oriented, rest on the outer surface (9) of the support cylinder (8) and are arranged beside one another around a rotation axis (3) to form a closed ring; and two end discs (14), which are arranged at the axially opposite ends of the support cylinder (8) and define lateral edges of an annular seat containing the main permanent magnets (6). A radially outer portion of each end disc (14) extending beyond the outer surface (9) of the support cylinder (8) is arranged at a non-zero axial distance (D) from the corresponding permanent magnets (6).