Spoke Rotor Frame Structure for High-Speed Motor Strength

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Solution Overview

Problem

Existing spoke type motors face issues with structural strength during high-speed operations, leading to potential breakage of the rotor due to centrifugal forces and insufficient coupling forces between fastening members, which also affect motor size and productivity.

Innovation Solution

A motor structure that integrates a rotor core and permanent magnets with a rotor frame using a bushing coupling portion, reinforcing ribs, and a rotor frame design that enhances structural strength through insert injection molding, ensuring stable mounting and improved coupling without increasing size or deteriorating performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

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

Engineering Contradiction:
Improverotor structural strengthVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent integrates the fastening function into the rotor frame structure itself by forming protrusions directly on the rotor frame that engage with grooves on the permanent magnet. This merging of the fastening function into the existing structural component eliminates the need for separate fastening members, thereby reinforcing rotor strength while avoiding increased device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor frame is designed to serve multiple functions: it provides structural support, generates centrifugal force during rotation, and simultaneously acts as a fastening mechanism through its protrusions that couple with the permanent magnet. This multi-functionality allows the rotor frame to reinforce structural strength without adding separate fastening components

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

2Reliability

If fastening members are introduced to prevent rotor breakage, then rotor reliability is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improverotor reliabilityVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastening function is merged into the rotor frame structure, which can be manufactured as a single integrated component using existing molding or machining processes. This eliminates the need for separate fastening member manufacturing and assembly operations, thereby improving rotor reliability while maintaining ease of manufacture

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protrusions for fastening are pre-formed as integral parts of the rotor frame structure during its manufacturing process. This preliminary formation of fastening features eliminates subsequent assembly steps, making the manufacturing process simpler while ensuring reliable rotor construction

Inventive Principle:
Principle #10Preliminary action

3Strength

If first and second fastening members are disposed above and below permanent magnet, then rotor strength is improved, but motor size increases

Engineering Contradiction:
Improverotor structural strengthVSAvoidmotor size
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The fastening function is merged into the rotor frame structure, eliminating the need for separate first and second fastening members disposed above and below the permanent magnet. This integration maintains rotor structural strength while avoiding the space occupation that would increase motor size

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor frame serves as both the structural support and the fastening mechanism through its protrusions. This multi-functionality eliminates the need for additional fastening members that would increase motor dimensions, thereby maintaining compact motor size while ensuring rotor strength

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

4Reliability

If multiple fastening members are used to secure rotor components, then rotor reliability is improved, but productivity decreases

Engineering Contradiction:
Improverotor assembly reliabilityVSAvoidassembly productivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The fastening function is merged into the rotor frame structure, which can be manufactured as a single integrated component. This eliminates the need for multiple separate fastening members and their corresponding assembly steps, thereby ensuring reliable rotor assembly while significantly improving productivity through reduced assembly operations

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protrusions for fastening are pre-formed as integral parts of the rotor frame structure during its manufacturing process. This preliminary formation of fastening features eliminates subsequent assembly steps, making the manufacturing process simpler while ensuring reliable rotor construction

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3657639B1motor
Publication Date: 2025.09.10 LG ELECTRONICS INC
  • EP3657639B1 patent drawingFigure 1
  • EP3657639B1 patent drawingFigure 2
  • EP3657639B1 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 rotor frame that couples the plurality of rotor core segments and the plurality of permanent magnets to each other, and an outer ring that is made of a non-magnetic material and that surrounds an outer end of the plurality of rotor core segments and an outer end of the plurality of permanent magnets. The plurality of rotor core segments and the plurality of permanent magnets are alternately arranged along the circumferential direction of the rotor.