Permanent Magnet Rotor End Plate Pressing Mechanism

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Solution Overview

Problem

The magnetic characteristics of permanent magnet-type rotary electric machines are compromised due to uneven plate thicknesses in the electromagnetic steel sheets, and existing solutions fail to effectively correct the spacing between the outer peripheral sides of these sheets, leading to potential collisions and decreased performance.

Innovation Solution

A rotor design that includes a pair of end plates with a pressing portion to abut and apply a pressing force to the outer peripheral sides of the rotor core, ensuring even spacing and maintaining magnetic characteristics, even when the electromagnetic steel sheets have uneven thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pair of end plates with flat contact surfaces are used to fix the rotor core, then the permanent magnets are regulated from moving, but spaces between outer peripheral sides of electromagnetic steel sheets cannot be corrected, decreasing magnetic characteristic

Engineering Contradiction:
Improvepermanent magnet stabilityVSAvoidmagnetic characteristic
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The end plate contact surface is divided into two functional regions: a flat contact surface region for regulating permanent magnet movement, and a pressing portion with a curved surface that presses the outer peripheral sides of electromagnetic steel sheets. This local differentiation allows each region to perform its specific function optimally without interfering with the other.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The contact surface of the end plate is segmented into distinct functional zones: one zone (flat surface) dedicated to permanent magnet regulation through pressing members, and another zone (pressing portion) dedicated to eliminating spaces between steel sheets. This segmentation enables independent optimization of each function.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If electromagnetic steel sheets with uneven plate thicknesses are laminated, then the rotor core can be assembled, but spaces are formed between outer peripheral sides, decreasing magnetic characteristic

Engineering Contradiction:
Improverotor core assemblyVSAvoidmagnetic characteristic
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The pressing portion applies mechanical pressure to change the physical state of the spaces between electromagnetic steel sheets, compressing them to eliminate gaps. This parameter change (from gapped to compressed) restores the magnetic characteristic without requiring precise control of the original plate thicknesses.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pressing portion is designed to preemptively counteract the harmful effect of uneven plate thicknesses by applying pressure before the rotor operates. This preliminary action eliminates spaces that would otherwise form due to thickness variations, preventing rather than correcting the problem during operation.

Inventive Principle:
Principle #9Preliminary anti-action

3Object-affected harmful factors

If pressing members are inserted into hole portions in end plates to regulate permanent magnet movement, then collision noise is prevented, but the structure becomes more complex

Engineering Contradiction:
Improvecollision noiseVSAvoidend plate structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The end plate structure is merged to perform multiple functions: the flat contact surface portion regulates permanent magnet movement to prevent collision noise, while the pressing portion simultaneously eliminates spaces between electromagnetic steel sheets. This merging reduces the need for separate components and simplifies the overall structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The end plate is designed as a multi-functional component where different portions serve different purposes: one portion (flat contact surface) addresses permanent magnet stability, another portion (pressing portion) addresses magnetic characteristic maintenance. This universality allows a single component to solve multiple problems that would otherwise require separate solutions.

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

Data Source

PatentEP3154156B1Rotor of permanent magnet-type rotary electric machine
Publication Date: 2021.03.10 FUJI ELECTRIC CO LTD
  • EP3154156B1 patent drawingFigure 1~2
  • EP3154156B1 patent drawingFigure 3A~4
  • EP3154156B1 patent drawingFigure 5~6B

AI summary

Provided is a rotor (1) of a permanent magnet-type electric rotary machine, the rotor being able to restrain a decrease of a magnetic characteristic. A pair of end plates (6a, 6b) placed at both axial ends of a rotor core (3) are each provided with a pressing portion (10, 10) configured to abut with an outer peripheral side of an end of the rotor core (3) to apply a pressing force toward the other end plate.