Electric Motor Stator Damping Layer for Vibration Reduction

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Solution Overview

Problem

Existing electric motors face challenges in minimizing vibrations and noises due to electromagnetic and mechanical forces, with current damping solutions focusing on bearings and shafts, but failing to effectively address magnetic force-induced oscillations.

Innovation Solution

The electric motor design incorporates a damping layer with high intrinsic damping characteristics, directly contacting the stator's pole body and housing, to reduce magnetic force-induced oscillations, using viscoelastic materials and various application methods, maintaining the original geometry and magnetic characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If damping materials with high intrinsic damping characteristics are used to reduce vibrations and noises, then the damping effect is improved, but the material selection becomes more restricted due to conflicting requirements for stiffness, strength, load capacity, temperature resistance, and magnetic characteristics

Engineering Contradiction:
Improvevibrations and noisesVSAvoidmaterial selection flexibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The stator is divided into two distinct parts: a pole body made from materials with high intrinsic damping characteristics for vibration reduction, and a yoke made from materials with suitable magnetic characteristics. This segmentation allows each component to be optimized for its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different materials are assigned to different locations within the stator based on local functional requirements. The pole body uses damping-optimized materials where vibration control is critical, while the yoke uses magnetically-optimized materials where magnetic performance is critical.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the strength and stiffness of electric motor components are increased to reduce vibrations and noises, then the damping effect is improved for constant rotational speeds, but the solution becomes ineffective when rotational speed or motor frequency varies due to resonance issues

Engineering Contradiction:
Improvevibrations and noisesVSAvoidperformance across variable operational conditions
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The damping characteristics of the pole body are enhanced by selecting materials with high intrinsic damping characteristics, which provides effective vibration reduction across a broader range of operating conditions compared to merely increasing stiffness. The damping effect is less sensitive to frequency variations than resonance-based solutions.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces vibrations and noises by dampening magnetic force-induced oscillations, improving the motor's operational stability and noise reduction, particularly when magnetic forces are dominant.

Implementation Method 1

The damping layer (9) comprises a material with an intrinsic damping characteristic that is higher compared with the material of the pole body (8) and compared with the material of the housing (6) of the stator acting as yoke

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

at least one pole body (8) of the stator is radially supported on the housing (6) by way of a damping layer (9)

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP3389166B1Electric motor
Publication Date: 2020.03.11 MAHLE INT GMBH
  • EP3389166B1 patent drawingFigure 1~3
  • EP3389166B1 patent drawingFigure 4~7

AI summary

The present invention relates to an electric motor (1) with a housing (6) acting as yoke (5), which encloses an external stator (3) in circumferential direction (7) and with an internal rotor (4), which is rotatably mounted on the housing (6) about an axis of rotation relative to the stator (4). It is substantial to the invention that at least one pole body (8) of the stator (3) is radially supported on the housing (6) by way of a damping layer (9) and that the damping layer (9) is directly in connection with the housing (6) and with the pole body (8).