Electric Machine Stator Fastening for Vibration Control

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Solution Overview

Problem

Electric machines experience excessive vibrations due to twice-line frequency vibrations, which existing methods attempt to mitigate by increasing stator core thickness or stiffening the motor frame, but these solutions often restrict performance or design limitations.

Innovation Solution

A novel fastening arrangement between the stator core and frame using four strategically positioned fastening points, allowing controlled contact and predictable vibration levels without restricting speed range or electric design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the stator yoke is made thicker to increase natural frequency and reduce vibration, then vibration levels are reduced, but the device complexity and material requirements increase

Engineering Contradiction:
Improvevibration levelsVSAvoidstator core thickness
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention changes the fastening parameters from multiple fastening points to exactly four fastening points positioned at specific locations (two at each axial end on opposite sides of the longitudinal centre axis). This parameter optimization achieves effective vibration control without increasing material thickness or structural complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies fastening points at specific critical locations rather than uniformly distributing fastening points. The four fastening points are strategically positioned at the axial ends on opposite sides of the longitudinal centre axis, providing localized vibration control where it is most effective.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the motor frame and end shields are stiffened to increase natural frequency, then vibration is reduced, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvevibration levelsVSAvoidframe stiffening
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention optimizes the fastening configuration to exactly four points with specific positioning, achieving vibration control through geometric optimization rather than structural stiffening. This maintains ease of manufacture while effectively controlling vibration.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If more fastening points are used to control vibration, then vibration control improves, but the device complexity increases

Engineering Contradiction:
Improvevibration controlVSAvoidnumber of fastening points
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention determines the optimal parameter of exactly four fastening points through analysis, achieving effective vibration control without the need for more numerous fastening points. This optimization balances vibration control effectiveness with structural simplicity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fastening point arrangement exhibits strategic asymmetry in positioning (at axial ends on opposite sides of the longitudinal centre axis) rather than uniform distribution, achieving effective vibration control with minimal fastening points.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP3738191B1An electric machine
Publication Date: 2021.12.29 ABB (SCHWEIZ) AG
  • EP3738191B1 patent drawingFigure 1
  • EP3738191B1 patent drawingFigure 2
  • EP3738191B1 patent drawingFigure 3~4

AI summary

The electric machine comprises a stator core (200) with a longitudinal centre axis (Z1-Z1) and a frame surrounding the stator core (200). The stator core (200) is attached to the frame through four fastening points (P1, P2, P3, P4), whereby two fastening points (P1, P2) are positioned at a first axial end of the stator core (200) on opposite sides of the longitudinal centre axis (Z1-Z1) and two fastening points (P3, P4) are positioned at a second opposite axial end of the stator core (200) on opposite sides of the longitudinal centre axis (Z1-Z1).