IPM Rotor Magnet Fixation Using Deformable V-Shaped Core Slots
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Solution Overview
Problem
Conventional methods for fixing permanent magnets in interior permanent magnet (IPM) rotors face issues such as excessive press-in force leading to rotor core damage, increased manufacturing costs due to complex mold requirements, and potential hindrance of magnetic flux, which affects motor performance.
Innovation Solution
A rotor design featuring a cylindrical core with laminated cores and V-shaped magnet accommodating holes, where protrusions and protrusion forming spaces are used to securely fix permanent magnets without adhesives, allowing for optimal press-in force and unobstructed magnetic flux flow, thus reducing manufacturing costs and maintaining motor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a press-fitting protrusion is used to fix the magnet, then the magnet can be securely fixed to the core main body, but the press-in force becomes too large and the rotor core may be scraped
Solution Approach 1:
The invention introduces a recess portion with reduced cross-sectional area in the press-fitting protrusion, creating a localized weak point that yields first during press-fitting. This local quality change allows the protrusion to deform preferentially at the recess portion, reducing the peak press-in force applied to the rotor core while still achieving secure magnet fixation through the deformed protrusion shape.
2Reliability
If core sheets having different shapes are laminated to hold the magnet, then the magnet can be secured, but transferring is required which leads to an increase in mold cost
Solution Approach 1:
The invention segments the press-fitting protrusion into two distinct portions: a first portion with a larger cross-sectional area that provides structural support and magnetic flux path, and a second portion with a smaller cross-sectional area that deforms to hold the magnet. This segmentation allows both core sheets to have the same overall shape, eliminating the need for complex transferring operations while achieving effective magnet holding.
3Reliability
If protrusions or recess portions are positioned to fix the magnet, then the magnet can be secured, but the magnetic flux flow may be hindered
Solution Approach 1:
The invention positions the recess portion and deformed second portion of the protrusion primarily in the axial direction rather than extending significantly in the radial direction. This dimensional arrangement allows the magnet fixation function to be achieved along the axial dimension while minimizing interference with the radial magnetic flux path, thus reducing magnetic flux obstruction.
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 solution effectively secures the permanent magnets with appropriate press-in force, prevents magnetic flux hindrance, and lowers manufacturing costs by eliminating the need for specialized molds and adhesives, thereby enhancing the operational efficiency and performance of the brushless motor.
Implementation Method 1
the protrusion is elastically deformed, and the permanent magnet can be fixed to the core main body with appropriate press-in force
Data Source
AI summary
A rotor includes a cylindrical core main body having a columnar space on a rotation center side. A plurality of magnet accommodating hole pair penetrates the core main body in an axial direction and includes a pair of magnets accommodating holes arranged in a V shape so as to be separated from each other toward one side of the core main body which is a stator side in a radial direction. A plurality of permanent magnets is fixed in the respective magnet accommodating holes. The plurality of permanent magnets come into pressure contact with the permanent magnet from the q-axis side and the other side in the radial direction. A protrusion forming space penetrates in the axial direction and extending from a side surface to the one side in the radial direction along the side surface.