Bridged Spoke-Type Rotor Core for High-Speed Motor Strength

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Solution Overview

Problem

Spoke type motors face structural strength issues due to excessive centrifugal forces at high speeds, leading to potential breakage of permanent magnets and rotor cores, and existing solutions either compromise efficiency or increase motor size, while also being inefficient in mass production.

Innovation Solution

A motor design featuring a rotor core with alternately arranged electrical steel sheets and bridges connecting rotor core segments, which enhances structural strength by stabilizing the assembly and reducing the number of parts required for assembly, thereby improving productivity and dimensional stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If multiple fastening members are used to secure permanent magnets and rotor core, then structural strength is improved, but device complexity and assembly difficulty increase

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

Solution Approach 1:

The patent merges the fastening function into the rotor core itself by forming protrusions that extend into the permanent magnets. This integration eliminates the need for separate fastening members, reducing assembly complexity while maintaining the structural strength needed to secure permanent magnets during high-speed rotation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor core structure provides its own fastening function through the protrusions formed as integral parts of the core. The protrusions automatically secure the permanent magnets during assembly without requiring additional fastening components, making the system self-sufficient and simplifying the overall structure.

Inventive Principle:
Principle #25Self-service

2Productivity

If rotor core segments are spaced apart to increase motor efficiency, then efficiency is improved, but structural strength deteriorates due to centrifugal force

Engineering Contradiction:
Improvemotor efficiencyVSAvoidstructural strength
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The rotor core is divided into multiple segments spaced apart from each other, creating gaps that improve motor efficiency by reducing magnetic saturation and improving flux distribution. The segments are connected by connecting portions that provide the necessary structural strength to withstand centrifugal forces during high-speed rotation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent solves the structural strength problem by adding a dimensional connection through connecting portions that link the spaced rotor core segments. This creates a three-dimensional structure where segments are separated in the radial direction for efficiency but connected in the axial direction for strength, effectively resolving the contradiction through dimensional transition.

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

3Strength

If multiple individual parts are used for rotor assembly, then structural strength can be improved, but productivity decreases due to sequential assembly requirements

Engineering Contradiction:
Improvestructural strengthVSAvoidassembly productivity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent combines multiple functions into fewer components. The rotor core integrates both the structural support function and the fastening function through its protrusions, eliminating the need for separate fastening members. This reduction in part count directly improves assembly productivity while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor core is designed to perform multiple functions simultaneously: it provides structural support, acts as a magnetic circuit, and serves as a fastening mechanism through its protrusions. This multi-functionality reduces the total number of components needed and simplifies the assembly process, thereby improving productivity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 prevents breakage of permanent magnets and rotor cores during high-speed operation by enhancing structural strength and maintaining efficiency, while simplifying the assembly process and reducing production complexity.

Implementation Method 1

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

Implementation Method 2

when the rotation shaft of the motor excessively rotates, a strong centrifugal force may act on the rotor of the motor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3657641B1motor
Publication Date: 2023.09.06 LG ELECTRONICS INC
  • EP3657641B1 patent drawingFigure 1
  • EP3657641B1 patent drawingFigure 2
  • EP3657641B1 patent drawingFigure 3

AI summary

A motor includes a stator and a rotor rotatably disposed at an inner side of the stator or an outer side of the stator. The rotor includes a rotor core block including a plurality of rotor core segments that are arranged along a circumferential direction of the rotor, where each of the rotor core segments includes a plurality of electrical steel sheets that are stacked on one another. The rotor further includes a plurality of permanent magnets disposed between the plurality of rotor core segments, where the plurality of rotor core segments and the plurality of permanent magnets are alternately arranged along the circumferential direction of the rotor. The plurality of electrical steel sheets include bridges that connect the plurality of rotor core segments to one another along the circumferential direction of the rotor.