Segmented Permanent Magnet Rotor Frame for High-Speed Strength

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Solution Overview

Problem

Existing motor designs face challenges in maintaining structural strength during high-speed operations without increasing size or degrading performance, particularly due to insufficient physical coupling forces between fastening members and components, which can lead to breakage under centrifugal forces.

Innovation Solution

A motor design featuring a rotor with alternately arranged rotor core segments and permanent magnets, coupled by a first frame made of high tensile strength material and a second frame with lower contraction ratio, which surrounds and integrates the components to enhance structural integrity and prevent breakage during high-speed operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fastening members are introduced to reinforce rotor structural strength, then structural strength is improved, but device complexity increases and manufacturing difficulty increases

Engineering Contradiction:
Improvestructural strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the fastening member function into the rotor core itself by forming protrusions directly on the rotor core surface. This eliminates separate fastening components while maintaining the structural strength enhancement, thereby reducing device complexity while improving strength retention during high-speed rotation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor core is segmented with multiple protrusions distributed around its circumference. This segmentation allows the structural reinforcement to be achieved through distributed features rather than a single complex fastening mechanism, simplifying the overall device structure while effectively preventing permanent magnet displacement.

Inventive Principle:
Principle #1Segmentation

2Reliability

If fastening members are introduced to prevent breakage during high-speed rotation, then reliability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
ImprovereliabilityVSAvoidease of manufacture
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastening function is merged into the rotor core manufacturing process itself. The protrusions are formed as integral features of the rotor core, allowing simultaneous production of both the rotor core and fastening structures in one manufacturing step, thereby improving ease of manufacture while ensuring reliability during high-speed operation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protrusions are formed on the rotor core before permanent magnet attachment. This preliminary action integrates the fastening feature creation into the rotor core manufacturing process, eliminating subsequent fastening member installation steps and improving manufacturing efficiency while ensuring reliable permanent magnet retention.

Inventive Principle:
Principle #10Preliminary action

3Strength

If rotor core size is reduced to accommodate larger fastening members, then structural strength is improved, but motor performance deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidmotor performance
Core Design Contradiction:
StrengthVSPower

Solution Approach 1:

The protrusions are formed as localized features on the rotor core surface rather than reducing the overall rotor core dimensions. This local quality approach provides structural reinforcement exactly where needed (at the permanent magnet attachment interface) while preserving the overall rotor core size and magnetic flux path, thereby maintaining motor performance while improving structural strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of adding fastening members in the radial dimension that would reduce rotor core area, the solution adds protrusions in the axial dimension on the rotor core surface. This dimensional shift provides fastening capability without encroaching on the radial space available for magnetic flux, thus preserving motor performance while enhancing structural strength.

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 improves structural strength and productivity by securely mounting rotor core segments and permanent magnets, preventing breakage and maintaining motor performance and size, while also addressing shrinkage issues during injection molding.

Implementation Method 1

When the rotation shaft of the motor excessively rotates, a strong centrifugal force may act on the rotor of the motor. Furthermore, this strong centrifugal force may cause breakage in which the permanent magnet or rotor core in the rotor is separated in a radial direction of the rotor.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

A motor is a device that can provide a rotational force generated by electromagnetic interaction between a stator and a rotor to a rotation shaft.

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP3657642B1motor
Publication Date: 2023.09.06 LG ELECTRONICS INC
  • EP3657642B1 patent drawingFigure 1
  • EP3657642B1 patent drawingFigure 2
  • EP3657642B1 patent drawingFigure 3

AI summary

A motor includes a stator and a rotor. The rotor includes: a plurality of rotor core segments arranged along a circumferential direction of the rotor on the inner side or the outer side of the stator and spaced apart from one another to define a plurality of permanent magnet arrangement slots between the plurality of rotor core segments; a plurality of permanent magnets inserted into the plurality of permanent magnet arrangement slots, respectively; a first frame that couples the plurality of rotor core segments to the plurality of permanent magnets, the first frame being made of a first material; and a second frame that surrounds the plurality of rotor core segments, the plurality of permanent magnets, and the first frame and that couples the plurality of rotor core segments, the plurality of permanent magnets, and the first frame to one another. The second frame is made of a second material different from the first material.