Electric Motor Air Gap Rollable Elements

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Solution Overview

Problem

Conventional electric motors face performance issues due to the air gap between the stator and rotor, which affects magnetic field strength and efficiency, and can lead to rotor jamming from thermal expansion and eccentricity, requiring mechanical support that restricts design and increases volume.

Innovation Solution

Incorporating rollable elements made of magnetic and non-magnetic materials within the air gap to minimize the air gap, allowing magnetic field lines to close directly between the stator and rotor, reducing magnetic reluctance and preventing jamming without the need for additional support bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the air gap size is reduced to improve magnetic field strength and efficiency, then the magnetic performance is improved, but the rotor may jam due to thermal expansion and eccentricity

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidrotor jamming risk
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

Rollable elements are introduced as intermediary components between the rotor and stator. These elements serve dual functions: they maintain a minimal air gap for optimal magnetic coupling while simultaneously preventing direct contact that would cause jamming. The rollable elements roll between the rotor surface and stator, accommodating thermal expansion and eccentricity variations without compromising the magnetic field strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If mechanical support bearings are added to prevent rotor jamming, then the reliability is improved, but the device complexity and volume increase

Engineering Contradiction:
Improverotor support stabilityVSAvoidsupport bearing structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rollable elements perform multiple functions simultaneously: they act as magnetic coupling mediators to maintain optimal air gap, serve as bearing elements to support the rotor and prevent jamming, and accommodate thermal and eccentricity variations. This multi-functionality eliminates the need for separate mechanical support bearings, reducing device complexity and volume while maintaining reliability.

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

3Stability of the object's composition

If conventional mechanical bearings are used to support the rotor, then the rotor stability is improved, but the total volume of the electric motor increases

Engineering Contradiction:
Improverotor stabilityVSAvoidmotor volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The magnetic coupling function and mechanical support function are merged into a single component system using rollable elements. These elements are positioned within the existing air gap space, combining the roles of magnetic flux mediator and rotor support bearing. This integration eliminates the need for additional external bearing structures, thereby maintaining rotor stability while minimizing the total motor volume.

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 enhances energy efficiency, reduces electrical current requirements, prevents rotor jamming, and allows for a more compact motor design by eliminating the need for support bearings, suitable for high-temperature operations and confined spaces.

Implementation Method 1

the magnitude of the magnetic field, and therefore the attractive force between the poles of the rotor and the stator, depends strongly on the size of the air gap

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

allowing magnetic field lines to close directly between the stator and rotor, reducing magnetic reluctance

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Implementation Method 3

jamming of the rotor may occur due to thermal expansion of the rotor and/or the stator

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

arranged to be in mechanical contact with both the external surface of the rotor and the cylindrical internal surface of the stator

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3583686B1Electric motor
Publication Date: 2021.03.10 ARRIVAL LTD
  • EP3583686B1 patent drawingFigure 1a
  • EP3583686B1 patent drawingFigure 1b
  • EP3583686B1 patent drawingFigure 1c~1d

AI summary

An electric motor is presented. The electric motor includes a rotor and a stator. A gap is provided between the rotor and the stator. A plurality of magnetic rollable elements are located in the gap.