Rotor Core Transfer Molding for Secure Magnet Insert Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The assembly of electric motors, particularly securing magnets within rotor core pockets, is challenging due to complexity and requires precise adhesive control for secure connections, which is difficult to achieve efficiently in high volume production.
Innovation Solution
A method involving transfer molding with a polymer preform that flows radially and axially through rotor core cavities to secure magnetizable inserts, using preheated components and tooling with venting and locating features to ensure efficient bonding, and an apparatus with upper and lower tooling to facilitate the molding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive materials are used to secure magnets within rotor core pockets, then magnets can be secured, but precise control of adhesive volume and curing behavior is challenging
Solution Approach 1:
The patent changes the physical state of the polymer material from solid preform to molten state through heating, enabling controlled flow to precisely fill cavities. The polymer is heated above its melting point to achieve complete and uniform filling of all rotor core cavities with magnetizable inserts, eliminating adhesive volume control issues.
Solution Approach 2:
The patent utilizes phase transition of the polymer material from solid to liquid state. The polymer preform is heated to melt and flow into cavities, then cooled to solidify and secure the magnetizable inserts. This phase change enables precise control of material distribution and curing behavior.
2Reliability
If adhesive materials are used to secure magnets within rotor core pockets, then magnets can be secured, but achieving assembly efficiency for high volume production is difficult
Solution Approach 1:
The patent combines multiple operations into a single transfer molding process: heating the polymer preform, melting it, forcing it through runners and gates into multiple rotor core cavities simultaneously, and cooling to secure all magnetizable inserts in one cycle. This eliminates sequential adhesive application and curing steps.
Solution Approach 2:
The polymer preform is prepared in advance with a geometry designed to melt and flow into the desired cavity configuration. The preform is positioned in the transfer molding apparatus before production, and the entire bonding process is pre-programmed, enabling rapid high-volume production.
3Manufacturing precision
If a polymer preform is displaced to flow through rotor core cavities, then precise filling of cavities is achieved, but polymer waste is generated
Solution Approach 1:
The patent separates useful polymer that fills cavities from waste polymer that accumulates in the transfer molding apparatus runners and gates. The waste polymer can be removed and potentially recovered or recycled, while the useful polymer remains bonded to the rotor cores.
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 method and apparatus provide a secure and efficient bonding of magnets within rotor cores, enhancing assembly efficiency and precision, suitable for high volume production of electric motors.
Implementation Method 1
displacing the polymer preform such that the polymer preform changes state and flows radially and then axially through each of the cavities of the rotor cores
Implementation Method 2
the polymer preform changes state and flows radially and then axially through each of the cavities
Implementation Method 3
the polymer preform is displaced vertically such that the polymer flows distally, in a gravitational direction, through the cavities
Implementation Method 4
securing the magnetizable inserts within the cavities of the rotor cores
Data Source
AI summary
A method of securing magnetizable inserts within cores of an electric converter includes placing an assembly of rotor cores in a transfer molding press, the magnetizable inserts being disposed within cavities of the rotor cores and the cavities of the rotor cores being in fluid communication, placing a polymer preform proximate a central portion of the assembly of rotor cores, displacing the polymer preform such that the polymer preform changes state and flows radially and then axially through each of the cavities of the rotor cores, removing the assembly of rotor cores from the transfer molding press, and removing polymer waste from the assembly of rotor cores.