Spherical Brushless Motor-Generator for High Torque in Compact Form

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Solution Overview

Problem

Existing motor-generators face challenges in achieving a balance between reduced weight and size while maintaining high torque and reliability, often resulting in compromised performance due to increased wear and complex designs.

Innovation Solution

A brushless motor-generator design featuring a spherical stator with uniformly offset poles and a rotor with a permanent magnet, where the permanent magnet is positioned inside the stator coils, optimizing magnetic field interaction for enhanced torque and reduced weight and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If brushes and collector contacts are used for current reversal in rotor winding, then the motor can operate with permanent magnets in stator, but the brushes wear out quickly and reduce reliability

Engineering Contradiction:
Improveservice lifeVSAvoidbrush wear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the brushes and collector contacts from the system entirely. Instead of using mechanical contact for current reversal, the invention employs a brushless design where current is supplied to the rotor winding through slip rings and brushes are eliminated, thus eliminating the wear problem and improving reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical brush-collector contact system with an electrical field-based solution. The current reversal in rotor winding is achieved through electromagnetic induction and controlled switching circuits rather than mechanical contact, eliminating friction and wear

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

2Device complexity

If toroidal magnets are glued to the rotor, then the rotor structure is simplified, but the magnets lose strength and may be destroyed during operation

Engineering Contradiction:
Improverotor structureVSAvoidmagnet strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent performs preliminary reinforcement of the rotor core before mounting the magnets. The rotor core is pre-strengthened with additional structural elements and mounting features that distribute mechanical stresses, preventing magnet destruction during operation while maintaining structural simplicity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses composite construction for the rotor, combining the toroidal magnets with a reinforced core structure made of high-strength materials. This composite design maintains the simplicity of the rotor structure while providing sufficient strength to prevent magnet destruction under operational stresses

Inventive Principle:
Principle #40Composite materials

3Area of stationary object

If the stator has large diameter with small magnets, then the motor fits space constraints, but the magnetic field becomes weak and torque decreases

Engineering Contradiction:
Improvestator diameterVSAvoidtorque
Core Design Contradiction:
Area of stationary objectVSForce

Solution Approach 1:

The patent applies local quality enhancement by concentrating magnetic flux in specific regions where it is most effective. The winding arrangement and magnetic circuit design focus the magnetic field in the air gap region, maximizing the interaction between stator and rotor fields despite the large diameter and small magnet size, thus maintaining adequate torque

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transitions from considering only the radial dimension to utilizing the axial dimension for magnetic flux path optimization. By designing the magnetic circuit to efficiently utilize the axial length of the stator and rotor, the patent compensates for the large diameter constraint and maintains sufficient magnetic field strength for adequate torque production

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

4Weight of moving object

If spherical stator with permanent magnet inside coils is used, then weight and size are reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvemotor weightVSAvoidmanufacturing complexity
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent divides the spherical stator into multiple segments or sections that can be manufactured separately using conventional techniques. Each segment contains portions of the winding and can be assembled to form the complete spherical structure, reducing manufacturing complexity while achieving the weight and size benefits of the spherical design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a nested structure where the permanent magnet is positioned inside the spherical stator coils, creating a compact concentric arrangement. This nesting approach minimizes the overall dimensions and weight while the modular nature of the nested components facilitates manufacturing and assembly

Inventive Principle:
Principle #7Nested doll (Nesting)

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

The design achieves increased reliability, reduced weight, and smaller size while maintaining high torque, resulting in a more efficient and durable motor-generator suitable for various applications.

Implementation Method 1

A brushless motor-generator design featuring a spherical stator with uniformly offset poles and a rotor with a permanent magnet, where the permanent magnet is positioned inside the stator coils, optimizing magnetic field interaction for enhanced torque

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Implementation Method 2

the permanent magnet is positioned inside the stator coils, optimizing magnetic field interaction for enhanced torque

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentEP3726711B1Brushless motor-generator
Publication Date: 2025.01.22 MEDZHLUMYAN RUBEN
  • EP3726711B1 patent drawingFigure 1
  • EP3726711B1 patent drawingFigure 2
  • EP3726711B1 patent drawingFigure 3

AI summary

A brushless motor-generator is disclosed, which the rotor being a permanent magnet and the stator with windings of rounded cross-section. The rotor is made in the form of a shaft with a permanent magnet fixed on it. The magnetic field vector of the poles of the magnet is perpendicular to the axis of rotation of the shaft. The stator is spherical, covering the magnet, and the axis of symmetry of the stator coincides with the axis of rotation of the shaft. From 1 to 12 windings are wound on the outer spherical surface of the stator; the windings forming the coils with uniformly offset poles relative to each other.