Laminated Rotor Assembly for Electric Motor Imbalance Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for reducing rotor imbalance in electric motors are inefficient, costly, and risk damaging the motor components, particularly when material is removed to balance the rotor, and there is a need for a simpler, quicker, and more reliable method to construct and assemble rotors.

Innovation Solution

The rotor design incorporates strategically arranged recesses in the laminations, including differently shaped and offset recesses to align the laminations precisely, allowing for balanced assembly and adjustment of imbalance during design or assembly, with optional cooling fluid passages, and adhesive fixation of magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If material is removed from the rotor to reduce imbalance, then the rotor imbalance is reduced, but the risk of damaging magnets and motor components increases

Engineering Contradiction:
Improverotor imbalanceVSAvoiddamage to magnets and components
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

Instead of removing material to reduce imbalance, the patent adds material in the form of adhesive to specific magnet recesses. This inverts the traditional approach by using material addition rather than removal, thereby reducing imbalance without the risk of damaging magnets or components through machining or drilling operations.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies adhesive selectively to specific magnet recesses based on the measured imbalance characteristics. By targeting only the necessary locations rather than uniformly treating the entire rotor, the method reduces imbalance precisely where needed while minimizing unnecessary material addition and avoiding damage to other areas.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If traditional balancing methods are used, then rotor imbalance can be reduced, but the construction process becomes more complex and time-consuming

Engineering Contradiction:
Improverotor imbalanceVSAvoidconstruction process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the balancing operation with the existing adhesive application process during motor assembly. By integrating imbalance correction into the routine adhesive application step rather than requiring separate balancing operations, the method reduces construction complexity and time while achieving the desired imbalance reduction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The method enables the rotor to be self-balanced by measuring its imbalance characteristics and applying adhesive accordingly. This eliminates the need for complex external balancing equipment and procedures, allowing the rotor to correct its own imbalance using simple adhesive application based on measurement data.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If material is removed to balance the rotor, then the imbalance is reduced, but the cost and time for construction increase

Engineering Contradiction:
Improverotor imbalanceVSAvoidconstruction speed and cost
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent measures and determines the optimal adhesive application locations before actual assembly. By pre-calculating where adhesive should be applied based on imbalance measurements, the method avoids time-consuming trial and error during assembly, thereby reducing construction time and cost while ensuring effective imbalance reduction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state and distribution of adhesive material to achieve balancing. By controlling the amount, location, and distribution of adhesive parameters, the method achieves imbalance reduction through material parameter optimization rather than through complex mechanical balancing operations, thereby improving productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4029119B1Rotor, electric motor and method for reducing the unbalance of a rotor
Publication Date: 2025.10.22 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP4029119B1 patent drawingFigure 1
  • EP4029119B1 patent drawingFigure 2~3
  • EP4029119B1 patent drawingFigure 4

AI summary

The invention relates to a rotor (22) for an electric motor (10), having a laminated rotor core (26) which is rotatable about a rotation axis (14) and has a first rotor lamination (24.1) and a second rotor lamination (24.2), which is arranged axially next to the first motor lamination (24.1), and having a plurality of magnet cutouts (32) in each of which magnets (30) are arranged and secured. The invention further relates to an electric motor (10) having a rotor (22) and a method for reducing the unbalance of a rotor (22).