Resin Transfer Molding for Stator Encapsulation in Small Gaps
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Solution Overview
Problem
Transfer molding is technically challenging for large components like stators or rotors in electric machines, particularly with thermosetting materials, as existing processes struggle to effectively encapsulate or pot components with precise control and filling of small gaps and openings.
Innovation Solution
A method and device for transfer molding that utilize low-viscosity thermosetting materials, such as one-component epoxy resin, with a tool comprising multiple mold parts and distribution ducts/runners for controlled flow and filling, allowing separate feeding, varying pressures, and staggered introduction of potting compound to adapt to component geometry and fill small gaps, along with optional warming and underpressure to prevent air pockets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transfer molding is used for large components like stators or rotors with thermosetting materials, then encapsulation can be achieved, but the process is technically challenging and difficult to implement
Solution Approach 1:
The injection system is divided into multiple independently controllable injection units, each capable of injecting potting compound through separate distribution ducts. This segmentation allows complex large components to be encapsulated by dividing the injection process into multiple manageable parts, improving both reliability and ease of manufacture.
Solution Approach 2:
The injection process is made dynamic by allowing varying pressures, temperatures, and injection rates to be applied independently to different distribution ducts during the encapsulation process. This dynamic control enables adaptation to different regions of large components, making the process more implementable while maintaining high encapsulation quality.
2Manufacturing precision
If low-viscosity thermosetting materials are used, then small gaps and openings can be filled effectively, but control of flow-fronts and filling procedure becomes more challenging
Solution Approach 1:
The distribution system is segmented into multiple ducts with independent control, allowing the flow of low-viscosity material to be managed in discrete controllable portions. This prevents uncontrolled flashing while ensuring complete filling of small gaps and openings.
Solution Approach 2:
Injection parameters such as pressure, temperature, and rate are dynamically adjusted for each distribution duct based on real-time flow-front monitoring. This allows precise control of low-viscosity material flow, achieving complete filling without requiring overly complex device architecture.
3Manufacturing precision
If multiple distribution ducts and runners are used for controlled filling, then filling precision improves, but the device structure becomes more complex
Solution Approach 1:
The distribution ducts and injection units are designed with multi-functionality, serving both as flow control elements and as integrated heating/pressure application points. This reduces the need for separate control mechanisms, lowering device complexity while maintaining high filling precision.
Solution Approach 2:
Each distribution duct is equipped with independently adjustable parameters (pressure, temperature, injection rate), allowing precise filling control without requiring complex mechanical structures. The parameter-based control simplifies the overall device architecture compared to mechanically complex flow control systems.
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
Enables efficient encapsulation of components with precise control over filling, ensuring complete filling of small gaps and openings, even in complex geometries, while optimizing the use of thermosetting materials for electric machine components like rotors and stators.
Implementation Method 1
Through the use of a low-viscosity material, the inserts/components in the tool can be treated with care, and even extremely small gaps and openings—such as are present, for instance, in windings of rotors or stators—can be filled
Implementation Method 2
conditioning, in particular warming, of the component and/or of the tool prior to introducing the potting compound
Implementation Method 3
applying an underpressure in the tool
Data Source
AI summary
A method for at least partially encapsulating or embedding components by resin transfer molding includes: placing a component into a mold of a resin transfer molding device; and introducing an embedding material into the mold through a plurality of runners and/or sprues.