Compact Gear Motor with Segmented Stator Teeth

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Solution Overview

Problem

Existing geared motors face challenges in achieving optimal size and mass reduction while maintaining performance and integrating with reducers, particularly in industrial and automotive applications where cost, lifespan, size, and mass are critical criteria.

Innovation Solution

A polyphase electric motor design with a stator featuring wide and narrow teeth, optimized coil placement, and a reduction gear system that minimizes residual torque and copper volume, allowing for compact integration with a reducer while maintaining performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the motor is integrated with a reducer to minimize size, then the external dimensions are reduced, but the mass and complexity of integration increase

Engineering Contradiction:
Improveexternal dimensionsVSAvoidintegration with reducer
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The motor and reducer are merged into a single integrated unit where the motor stator serves as the reducer housing. The motor shaft is directly coupled to the pinion gear, eliminating the need for separate mounting flanges and coupling mechanisms. This integration reduces the number of external components and simplifies the overall structure while maintaining compact dimensions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The stator structure serves multiple functions: it provides the magnetic circuit for motor operation, acts as the housing for the reduction gear mechanism, and serves as the mounting structure for the entire assembly. This multi-functionality reduces the number of separate components needed and simplifies integration with the reducer.

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

2Ease of manufacture

If the number of coils is reduced to simplify connections, then the manufacturing complexity decreases, but the torque performance may be compromised

Engineering Contradiction:
Improveconnections of the motorVSAvoidtorque performance
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The stator teeth are designed with varying widths: wider teeth at positions where coils are wound to provide sufficient magnetic flux and torque, and narrower teeth where no coils are placed. This local variation in tooth width optimizes the magnetic circuit efficiency at coil locations while maintaining structural integrity elsewhere, ensuring adequate torque performance with fewer coils.

Inventive Principle:
Principle #3Local quality

3Loss of substance

If wide teeth and narrow teeth are used to optimize copper volume, then the copper usage is minimized, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvevolume of copperVSAvoidtooth width variation
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The stator circumference is segmented into alternating wide and narrow teeth, with each tooth type serving specific functions. Wide teeth accommodate coils and provide primary torque generation, while narrow teeth provide structural support and magnetic flux pathways. This segmentation allows optimization of copper placement while maintaining manufacturability through standardized tooth patterns.

Inventive Principle:
Principle #1Segmentation

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 solution enables a compact, economical, and robust geared motor with reduced external dimensions and mass, optimized copper volume, and low residual torque, suitable for large series production.

Implementation Method 1

a rotor (14) having N pairs of poles (A1 to A10) magnetized radially in alternate directions

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The windings (15 to 17) are placed around the wide teeth (2 to 7) which makes it possible to obtain the maximum torque per ampere-turn of the motor

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP2171831B1Gear motor including a compact multiple-phase electric motor
Publication Date: 2016.06.15 MOVING MAGNET TECH
  • EP2171831B1 patent drawingFigure 1~2
  • EP2171831B1 patent drawingFigure 3~4
  • EP2171831B1 patent drawingFigure 5

AI summary

The invention relates to a gear motor including a multiple-phase electric motor formed by a stator portion excited by electric coils and by a rotor having N pairs of poles radially magnetised in alternating directions, the stator portion including two angular sectors alpha-1 and alpha-2 with respective radii R1 and R2, comprising wide teeth and narrow teeth radially extending from an annular crown, characterised in that the wide teeth have a width higher than or equal to twice the width of the narrow teeth, in that the notch width is higher than the width of a narrow tooth, in that the angular sector alpha-1 is lower than 220° and includes all the coils, and in that the ratio R1/R2 ranges from 1.2 to 2.