Brushless DC Motor Stator Rotor Angular Width Ratio

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Solution Overview

Problem

Manufacturers of electromechanical actuators face high development and industrialization costs due to the need for specific designs and tools for each motor configuration, as well as differing components for synchronous, asynchronous, and DC motors, which complicates the production of actuators with varying torque characteristics.

Innovation Solution

An electromechanical actuator design featuring a stator with a common profile capable of cooperating with multiple rotors, allowing for the production of motors with different torque values using a single stator arrangement, thereby reducing manufacturing costs and simplifying production processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If different motor configurations (synchronous, asynchronous, DC) are used to meet varying torque requirements, then torque characteristics are improved, but device complexity and manufacturing costs increase due to requiring different stators and rotors for each motor type

Engineering Contradiction:
Improvetorque characteristicsVSAvoidmotor configuration variety
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent applies universality by designing a stator with a common profile that can cooperate with multiple types of rotors (synchronous, asynchronous, DC motors). The stator's pole elements are dimensioned with an angular pole opening width less than the angular width of magnetic elements of the rotors, allowing the same stator to work with different rotor configurations to deliver different torque values, thereby reducing the need for separate stator designs for each motor type.

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

2Manufacturing precision

If specific designs and tools are created for each motor configuration, then manufacturing precision is improved, but ease of manufacture deteriorates due to requiring multiple specific designs and industrial tools

Engineering Contradiction:
Improvemotor configuration specificityVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent enables a single stator design to be used across multiple actuator types by ensuring the pole elements have an angular pole opening width less than the angular width of magnetic elements of the rotors. This universal stator profile allows the same manufacturing process and tools to produce stators for synchronous, asynchronous, and DC motors, simplifying production while maintaining precision requirements.

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

Solution Approach 2:

The patent utilizes parameter changes by varying the angular width of magnetic elements in different rotors while maintaining a common stator profile. By changing only the rotor parameters (angular width of magnetic elements) rather than the stator parameters, the same manufacturing process can produce different motor configurations with appropriate torque characteristics.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If a common stator profile is used for multiple rotor types, then ease of manufacture is improved, but manufacturing precision may deteriorate due to the need to accommodate different rotor configurations

Engineering Contradiction:
Improvestandardized constructionVSAvoidcooperation between stator and rotor
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by designing the stator's pole elements with specific dimensional characteristics (angular pole opening width less than the angular width of magnetic elements of the rotors) that locally accommodate different rotor configurations. This localized design feature ensures proper magnetic coupling and torque transmission for various rotor types while maintaining a common overall stator profile.

Inventive Principle:
Principle #3Local quality

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 approach enables the production of actuators with different torque values using a common stator design, reducing development and industrialization costs while allowing for a range of actuators to be manufactured with a standardized construction, thus addressing the issue of varying torque requirements.

Implementation Method 1

The motor includes a rotor and a stator positioned coaxially around an axis of rotation. The rotor comprises a rotor body provided with magnetic elements surrounded by the stator. The magnetic elements constitute pairs of poles. The stator is formed by a stator core comprising pole elements distributed over the periphery of the stator.

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2908412B1Electromechanical actuator comprising an electric motor, installation comprising such an actuator, range of actuators and related manufacturing method
Publication Date: 2020.03.18 SOMFY ACTIVITES SA
  • EP2908412B1 patent drawingFigure 1~2
  • EP2908412B1 patent drawingFigure 3~4
  • EP2908412B1 patent drawingFigure 5~6

AI summary

This electromechanical actuator comprises an electronically commutated, brushless DC electric motor (12). The motor (12) includes a rotor (13) and a stator (14) positioned coaxially around an axis of rotation. The rotor (13) comprises a rotor body (15) equipped with magnetic elements (16) surrounded by the stator (14). These magnetic elements (16) surround the rotor body (15). They constitute a permanent magnet and pole pairs. The stator (14) is formed by a stator core (17) comprising pole elements (28) distributed around the periphery of the stator (14). These pole elements (28) have an angular pole opening width (A) at least twice as small as the angular width (α1) of the magnetic elements (16) of the rotor (13).