Rotor Core Hole Rows Offset Centrifugal Force

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Solution Overview

Problem

Conventional rotating electric machine rotors face challenges in managing the increase in centrifugal force at high rotation speeds, leading to significant changes in the inner diameter of the rotor core.

Innovation Solution

A rotor design with a rotor core featuring annular shape, radial interference coupling with a shaft, and magnets arranged in multiple layers, incorporating slits and bridges to offset the centrifugal force distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the rotation speed of the rotating electric machine is increased, then the power output is improved, but the centrifugal force increases causing a larger change in the inner diameter of the rotor core

Engineering Contradiction:
Improvepower outputVSAvoidinner diameter stability of rotor core
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The rotor core is segmented into multiple sections by dividing the hole row into a first hole row and a second hole row at different radial positions. This segmentation allows each section to independently manage stress distribution, reducing the overall change in inner diameter under centrifugal force while enabling higher rotation speeds for improved power output

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-row hole configuration to a multi-row hole configuration with different radial positions. By adding the radial dimension as a variable (first radial position vs. second radial position), the design creates a three-dimensional stress distribution pattern that better accommodates centrifugal force, reducing inner diameter change while maintaining power output capabilities

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 effectively reduces the change in the rotor core's inner diameter due to centrifugal force, allowing for higher rotation speeds and improved torque transmission.

Implementation Method 1

a rotor shaft that is disposed radially inside the rotor core and is coupled to the rotor core by radial interference

Methodology Applied
Scientific EffectRadial interference: Elasticity

Data Source

PatentEP4668544A1Rotating electric machine rotor
Publication Date: 2025.12.24 AISIN CORP
  • EP4668544A1 patent drawingFigure 1
  • EP4668544A1 patent drawingFigure 2
  • EP4668544A1 patent drawingFigure 3

AI summary

Disclosed is a rotor for a rotating electric machine, the rotor including: a rotor core that has an annular shape as viewed in an axial direction; a rotor shaft that is disposed radially inside the rotor core and is coupled to the rotor core by radial interference; and magnets that are disposed in the rotor core on a per-magnetic-pole basis so as to form a plurality of magnetic poles along a circumferential direction. The rotor core has a plurality of holes on a radially inner side of the magnets, the plurality of holes extending in the axial direction. The plurality of holes form a first hole row and a second hole row at a first radial position and a second radial position, respectively, in order from closest to radial positions of the magnets, the first hole row and the second hole row each being aligned in the circumferential direction. A first circumferential range between the plurality of holes that are adjacent to each other and form the first hole row is circumferentially offset with respect to a circumferential position between the magnets of the respective magnetic poles.