Injection Molded Rotor Magnets Radial Support Dynamics
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Solution Overview
Problem
Existing methods for forming rotors in electric machines face challenges in accurately forming injection molded magnets and laminations, particularly in minimizing deformation and ensuring easy removal of the rotor from the die cavity, leading to potential damage and operational issues.
Innovation Solution
A die assembly with radially movable support shoes and a magnetic slurry injection system that applies pressure and aligns magnetic particles within a polymer to form permanent magnets within the rotor core, while minimizing deformation through controlled radial movement and magnetic field alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing methods are used for forming rotors in electric machines, then the rotor can be formed, but deformation occurs and removal from die cavity is difficult causing potential damage
Solution Approach 1:
The die assembly employs radially movable support shoes that can dynamically adjust their position. During injection molding, the support shoes are in a first position to provide precise radial support for forming magnets. During removal, they move to a second position (retracted radially) to reduce friction and prevent damage, enabling easy rotor extraction while maintaining forming accuracy.
Solution Approach 2:
The die assembly is segmented into multiple independent support shoes rather than a continuous rigid structure. Each support shoe can move independently radially, allowing localized adjustment during different process stages. This segmentation enables the support structure to adapt to both forming and removal requirements without compromising either precision or ease of extraction.
2Manufacturing precision
If radial support is provided during injection molding, then manufacturing precision is improved, but removal difficulty increases due to friction
Solution Approach 1:
The support shoes transition from a static to a dynamic configuration, moving radially between two positions. During injection molding, they extend to provide maximum radial support for precision forming. During removal, they retract to minimize contact and friction, solving the contradiction between needing support for precision and needing minimal friction for easy removal.
Solution Approach 2:
The support shoes undergo periodic movement between extended and retracted positions corresponding to different phases of the manufacturing cycle. They are extended during the molding phase for precision support and retracted during the removal phase for easy extraction, creating a rhythmic alternation that satisfies both contradictory requirements at different times.
3Productivity
If magnetic slurry is injected under pressure, then magnets are formed effectively, but particle alignment may be insufficient without additional alignment mechanisms
Solution Approach 1:
The system merges two functions into a single integrated support shoe structure: mechanical support for the rotor core and magnetic alignment of particles. The support shoes are equipped with magnets that simultaneously provide structural support during injection and magnetic field for particle alignment, eliminating the need for separate alignment mechanisms and maintaining both productivity and precision.
Solution Approach 2:
Magnetic fields are introduced as an intermediary mechanism between the injection process and the magnetic particles. The support shoes generate magnetic fields that mediate the alignment of magnetic particles within the slurry during injection, ensuring proper orientation without interfering with the injection pressure and flow dynamics.
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 reduces deformation and facilitates easy removal of the rotor, maintaining structural integrity and improving magnetic properties, thus enhancing the performance and reliability of electric machine rotors.
Implementation Method 1
an injection system for filling at least one of the plurality of voids of the rotor core with a magnetic slurry
Implementation Method 2
a plurality of alignment magnets configured to align the magnetic slurry
Data Source
AI summary
An apparatus or assembly for forming injection molded magnets in permanent magnet rotors or laminations for such rotors. The assembly includes a plurality of platens defining an axial boundary of a die cavity and a plurality of support shoes that are radially moveable between a closed position defining a radial boundary of the die cavity, and an open position creating a gap between the rotor core and the plurality of support shoes. The assembly has an injection system for filling at least one of the plurality of voids of the rotor core with a magnetic slurry, and a plurality of alignment magnets configured to magnetically align the magnetic slurry.