Three-Phase DC Motor Stator Segmentation for Reduced Wing Thickness

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Three-phase DC motors used in aircraft flight control surfaces face limitations in reducing wing thickness due to the cylindrical shape of the stator, which restricts motor torque, necessitating the combination of multiple small motors to achieve desired output, complicating mechanical and control considerations.

Innovation Solution

A three-phase DC motor design with a rotor having alternating N and S poles and a stator with coils wound around adjacent teeth, where the coils are offset by 1/3 pole pitch, allowing for reduced stator width and increased torque without combining motor outputs, utilizing a distributed winding configuration to minimize vibration and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cylindrical stator is used in a three-phase DC motor, then the motor structure is simple and easy to manufacture, but the stator width cannot be reduced, limiting wing thickness reduction in aircraft

Engineering Contradiction:
Improvestator structure simplicityVSAvoidstator width
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The stator is divided into multiple independent teeth (first tooth, second tooth, third tooth, etc.) arranged around the rotor. Each tooth can be independently wound with coils, allowing modular design and assembly. This segmentation enables the stator to achieve the desired width reduction while maintaining structural integrity and ease of manufacture through standardized tooth modules.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a traditional cylindrical stator configuration to a planar arrangement of teeth with specific spatial relationships. By defining teeth positions using virtual planes and angular relationships (e.g., teeth arranged within specific angle ranges around the rotor axis), the design optimizes the width dimension while maintaining manufacturability through standardized geometric relationships.

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

2Length of stationary object

If the stator width is reduced to decrease wing thickness, then wing thickness is reduced, but motor torque decreases

Engineering Contradiction:
Improvestator widthVSAvoidmotor torque
Core Design Contradiction:
Length of stationary objectVSForce

Solution Approach 1:

The patent applies different coil configurations to different teeth based on their positions. Specifically, teeth within certain angular ranges are wound with coils, while others may have different winding patterns or no coils. This localized optimization ensures that torque-generating regions are maximized within the reduced width constraint, maintaining motor torque by concentrating magnetic interaction in optimal zones rather than uniformly distributing it.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent optimizes torque by carefully controlling the angular positions and spacing of teeth and coils. By defining specific angular relationships (e.g., teeth arranged within 60-120 degree ranges, coils offset by specific angles), the design maximizes the magnetic field interaction efficiency within the reduced stator width, thereby maintaining adequate torque output despite the smaller physical dimensions.

Inventive Principle:
Principle #35Parameter changes

3Force

If multiple small motors are combined to achieve desired torque output, then the desired torque is achieved, but mechanical and control complexity increases

Engineering Contradiction:
Improvetorque outputVSAvoidmechanical and control complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges multiple torque-generating elements (teeth and coils) into a single integrated stator-rotor assembly. Instead of using multiple separate motors, the design combines multiple teeth with their respective coils into one unified motor structure that produces the desired torque output. This consolidation eliminates the need for complex mechanical coupling and synchronized control of multiple motors while achieving the same torque goal.

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 design enables reduced wing thickness while maintaining desired motor torque, eliminating the need for combining multiple motors, and reduces vibration and noise, enhancing reliability and stability.

Implementation Method 1

three or more coils wound around said teeth, said coils being placed only within a range defined by second virtual planes... a first coil through which a first phase current flows, a second coil through which a second phase current flows, and a third coil through which a third phase current flows

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a rotor having a outer surface and magnets; said outer surface of said rotor being configured to have alternating poles of N and S around a circumference of said rotor

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentEP2479870B1Three-phase DC motor
Publication Date: 2015.11.18 NABTESCO CORP
  • EP2479870B1 patent drawingFigure 1
  • EP2479870B1 patent drawingFigure 2~3
  • EP2479870B1 patent drawingFigure 4~5

AI summary

A three-phase DC motor includes a rotor 30 having poles 30a; a stator 28 including a plurality of core units 32b that are arranged around the rotor 30 and have an inner surface opposite to an outer surface of the rotor 30; and three or more coils wound around the core units 32b. The outer surface of the rotor 30 has alternating poles of N and S around the circumference of the rotor 30. The coils 35a, 35b, 35c, and 35d are placed only within a range defined by second virtual planes P2, these second virtual planes being specified respectively by rotating a first virtual plane P1 according to a predetermined angle in a rotor rotating direction and a direction opposite thereto. The first virtual plane P1 is a plane passing through the axial center O of the rotor 30. The inner surface of the adjacent 3N (N = 1, 2, 3, ...) number of core units 32b of the core units 32b, 32b, ... are delimited in within a width of one pole on the outer surface of the rotor 30.