Flexible PCB Stator Assembly for Compact AC Motor Torque

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Solution Overview

Problem

The structure of existing motor stators, particularly in small motors, is complex and difficult to process and assemble due to the presence of stator slots and armature windings.

Innovation Solution

A motor stator design featuring a stator yoke with a cavity and a flexible circuit board that includes conductive layers with coils, which are attached to the stator yoke, generating a radial magnetic field and interacting with the rotor magnetic field to produce electromagnetic torque, eliminating the need for stator slots and simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional stator slots and armature windings are used, then the motor can generate electromagnetic torque, but the structure becomes complex and difficult to process and assemble in small motors

Engineering Contradiction:
Improveprocessing and assembly convenienceVSAvoidstator structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the stator core and armature winding into an integrated stator assembly. The armature winding is directly embedded in the stator core without separate stator slots, merging two previously separate components into one unified structure that is easier to manufacture and assemble while maintaining electromagnetic torque generation capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates the separate stator slot structure from the design. By removing the need for distinct stator slots and pre-assembled armature windings, the design simplifies the manufacturing process and assembly steps while preserving the essential function of electromagnetic torque generation through direct embedding of windings in the stator core

Inventive Principle:
Principle #2Taking out (Extraction)

2Volume of moving object

If stator slots and armature windings are used, then electromagnetic torque can be generated, but the structural volume increases

Engineering Contradiction:
Improvestator structural volumeVSAvoidelectromagnetic torque generation
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The integration of stator core and armature winding into a single assembly reduces the overall structural volume by eliminating gaps and interfaces between separate components, while maintaining the electromagnetic torque generation function through the direct embedding configuration

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

The design reduces structural volume, improves processing convenience, and enhances assembly efficiency by attaching the flexible circuit board directly to the stator yoke, while maintaining high torque density and reliability.

Implementation Method 1

The current passes through the coil, generating a radial magnetic field perpendicular to the stator yoke in an air gap of the motor, and interacts with a rotor magnetic field to generate an electromagnetic torque

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The current passes through the coil, generating a radial magnetic field perpendicular to the stator yoke in an air gap of the motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4704312A1Motor stator and alternating current motor
Publication Date: 2026.03.04 FORTIOR TECHNOLOGY (SHANGHAI) CO LTD
  • EP4704312A1 patent drawingFigure 1~2
  • EP4704312A1 patent drawingFigure 3
  • EP4704312A1 patent drawingFigure 4a~5

AI summary

Disclosed are a motor stator and an AC motor. The motor stator includes a stator yoke and a stator winding. A cavity is provided inside the stator yoke. The stator winding includes a flexible circuit board formed by winding and having a same shape as the cavity. The flexible circuit board includes a plurality of groups of coils, the plurality of groups of coils are provided at intervals along a circumference of the stator yoke and are electrically connected to the terminal. The flexible circuit board is attached to an inner wall of the stator yoke. Current passes through the coil, generating a radial magnetic field perpendicular to the stator yoke in an air gap of the motor, and interacts with a rotor magnetic field to generate an electromagnetic torque required for an operation of the motor.