Electric Motor Stator Clamping for Adhesive-Free Assembly

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Solution Overview

Problem

Existing methods for assembling electric motors, whether internal or external rotor types, face challenges in minimizing material costs and simplifying the assembly process to enable automatable and quality-assured large-scale production, as they often require additional materials and complex processes.

Innovation Solution

The design features bow-like raised sections with radial recesses on the stator's peripheral surface, forming a non-positive connection with a carrier unit, which allows for a simplified and cost-effective clamping mechanism that reduces vibrations and mechanical influences, enabling a rotary-clamp connection without the need for adhesives or additional assemblies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive is used to secure the stator in the carrier unit, then the stator is firmly held, but additional material cost and complex application process are incurred

Engineering Contradiction:
Improvestator holding strengthVSAvoidassembly process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent removes the adhesive material and its application process entirely by replacing it with a mechanical clamping connection using raised sections and grooves that provide firm holding through geometric interlocking alone

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the chemical bonding mechanism (adhesive) with a mechanical interlocking system consisting of raised sections on the stator that engage with grooves in the carrier unit, eliminating the need for additional materials and complex application processes

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

2Loss of substance

If shrink-fitting is used to secure the stator, then additional material is avoided, but dimensional tolerances and preparation requirements increase complexity

Engineering Contradiction:
Improvematerial usageVSAvoiddimensional tolerance requirements
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the connection mechanism from dimensional interference fit (shrink-fitting) to geometric interlocking with play compensation, where the raised sections engage with grooves allowing for tolerance variations without requiring high manufacturing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a dynamic element by allowing the raised sections to be elastically deformable, enabling the connection to adapt to dimensional variations and tolerate manufacturing tolerances while maintaining secure connection

Inventive Principle:
Principle #15Dynamics

3Strength

If additional assembly with profiles is used for external rotor motors, then the stator is securely mounted, but device complexity and production cost increase

Engineering Contradiction:
Improvestator mounting strengthVSAvoidassembly structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the stator and carrier unit into a single integrated assembly by forming the raised sections directly on the stator body, eliminating the need for separate profile assemblies and reducing the number of components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent removes the additional profile assembly and its associated connection process by integrating the clamping features directly into the stator structure through raised sections that engage with the carrier unit

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If complex connection processes are used, then reliable connection is achieved, but productivity and automation capability are reduced

Engineering Contradiction:
Improveconnection reliabilityVSAvoidproduction throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent designs a self-aligning and self-clamping connection where the raised sections automatically engage with the grooves in the carrier unit during assembly, eliminating the need for complex positioning and fastening operations and enabling automated production

Inventive Principle:
Principle #25Self-service

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 solution simplifies the assembly process, reduces material costs, and enhances the mechanical stability of electric motors, facilitating automatable large-scale production while maintaining quality and operational readiness.

Implementation Method 1

at least one of the raised sections located on the stator side between the radial recesses is provided with a slot-like opening in the manner of a bracket, which extends axially parallel to the axis of rotation and circumferentially with a bracket-like cross-sectional profile over a predetermined (rotational) angular section within the respective raised section. This creates a bracket-shaped and elastic structure

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the raised sections cooperate to form a force-locking connection with a circumferential surface of the carrier unit

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3659239B1Electric motor and method for assembling an electric motor
Publication Date: 2024.01.31 EBM PAPST ST GEORGEN GMBH & CO KG
  • EP3659239B1 patent drawingFigure 1~2
  • EP3659239B1 patent drawingFigure 3~4
  • EP3659239B1 patent drawingFigure 5~6

AI summary

The invention relates to an electric motor, designed as an internal rotor electric motor or as an external rotor electric motor, having a stator (10, 40) designed to support an energisable winding, a rotor (70) mounted so as to be rotatable relative to the stator in a peripheral direction about an axis of rotation, and a stationary support unit (20, 30, 50, 60) for fastening and holding the stator. According to the invention, stirrup-like elevation portions (14, 44) with radial indentations (16, 46) arranged therebetween are formed on a stator peripheral surface and a slit-like stator axial aperture (18, 48) extends in the peripheral direction at least in some sections along the elevation portions, wherein the elevation portions cooperate to form a frictionally engaged connection with a peripheral face of the support unit. In a further embodiment the frictionally engaged connection can be configured as a fully clamping connection or as a twist-and-clamp connection.