Magnet Segment Cleavage via Variable Depth Notches

Solution Overview

Problem

The existing method of manufacturing magnet segments for field pole magnet bodies in permanent magnet rotary electric machines is prone to abnormal cracks due to significant size differences between initial cleavage pieces, leading to strength loss and potential thermal demagnetization.

Innovation Solution

A method involving sequential cleavage of magnet material at multiple target regions with notches, where the depth of notches closer to one side edge is deeper, reducing the likelihood of abnormal cracks and allowing for efficient size variation management during cleavage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the magnet material is cleft into three or more magnet segments through sequential three-point bending, then the magnet segments can be manufactured with reduced volume to suppress eddy current, but a significant size difference between initial cleavage pieces causes abnormal cracks due to strength loss

Engineering Contradiction:

Improvemagnet segment volumeVSAvoidcrack resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by forming notches at the cleavage target regions before the actual cleavage process. These notches are created in advance to control the stress distribution and cleavage initiation points, ensuring that the sequential bending process produces segments with controlled size differences without generating abnormal cracks. The notches serve as predetermined weak points that guide the cleavage process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by varying the depth of notches at different cleavage target regions. The notch depth is made shallower as the distance from the side edge increases, creating different local properties at different positions. This gradual variation in notch depth allows the magnet material to be cleaved sequentially while maintaining sufficient strength in each piece to prevent abnormal crack propagation.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If uniform notch depth is used at all cleavage target regions, then the manufacturing process is simpler, but significant size differences between cleavage pieces cause strength loss and abnormal cracks

Engineering Contradiction:

Improvenotch formation simplicityVSAvoidmagnet piece strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent implements local quality by varying the depth of notches at different cleavage target regions. The notch depth is made shallower as the distance from the side edge increases, creating different local properties at different positions. This gradual variation in notch depth allows the magnet material to be cleaved sequentially while maintaining sufficient strength in each piece to prevent abnormal crack propagation.

Inventive Principle:

Principle #3Local quality

3Temperature

If the magnet material is cleaved into multiple segments, then eddy current and heating are suppressed, but the manufacturing process becomes more complex with multiple cleavage operations

Engineering Contradiction:

Improveheating suppressionVSAvoidcleavage process complexity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming notches at the cleavage target regions before the actual cleavage process. These notches are created in advance to control the stress distribution and cleavage initiation points, ensuring that the sequential bending process produces segments with controlled size differences without generating abnormal cracks. The notches serve as predetermined weak points that guide the cleavage process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent divides the magnet material into multiple magnet segments through sequential cleavage at multiple target regions. This segmentation reduces the volume of each individual magnet segment, which in turn suppresses eddy current generation and the associated heating effects during motor operation.

Inventive Principle:

Principle #1Segmentation

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

This approach effectively suppresses abnormal crack generation, maintains magnetic strength, and reduces cycle time by allowing for consistent cleavage without size matching, thus preventing thermal demagnetization and improving manufacturing efficiency.

Implementation Method 1

it is conceived that the magnet material may be sequentially cleft into magnet segments one by one from one side edge of the magnet material through three-point bending

Methodology Applied

Scientific EffectThree-point bending: Fracture Mechanics

Data Source

PatentUS9251951B2Method of manufacturing magnet segment of field pole magnet body

Publication Date: 2016.02.02 NISSAN MOTOR CO LTD

AI summary

A method of manufacturing a magnet segment of a field pole magnet body includes cleaving a magnet material at a plurality of cleavage target regions arranged with an interval in a longitudinal direction of the magnet material. The cleavage process includes cleaving the magnet material sequentially from the cleavage target region closer to one side edge of the longitudinal direction of the magnet material, wherein a notch is formed in each of the plurality of cleavage target regions of the magnet material such that a depth of the notch closer to the one side edge becomes deeper.