Inflatable Mandrel Overmoulding for Stator Resin Encapsulation
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Solution Overview
Problem
Existing methods for embedding two-component resin in electric motor stator windings are inefficient due to long cooling times and mechanical stress during core removal, leading to resin damage and core deterioration.
Innovation Solution
A method involving a core with inflatable/deflatable chambers is used to create a temporary sealing contact with the stator surfaces, allowing immediate separation of the resin-coated stator from the core after curing, reducing cooling time and mechanical force required for core removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If forced cooling is applied to speed up the cooling process, then productivity is improved, but the resin coating may develop fissures and cracks
Solution Approach 1:
The patent replaces the thermal field (cooling system) with a pneumatic field (inflatable/deflatable chambers). Instead of using forced cooling to accelerate separation, the invention uses inflation to create separation during the curing process itself, eliminating the need for subsequent forced cooling operations that could damage the resin coating.
Solution Approach 2:
The patent applies preliminary action by inflating the chambers during the resin curing process to create immediate separation between the core and stator windings. This preliminary separation action prevents the need for later forced cooling and removal operations that could compromise resin coating integrity.
2Productivity
If significant mechanical force is applied to remove the core from the stator, then productivity is improved, but the core surface develops scratches and abrasions
Solution Approach 1:
The patent applies preliminary action by inflating the chambers during resin curing to create separation between the core and stator windings before removal. This preliminary separation dramatically reduces the mechanical force needed for core extraction, preventing surface damage while maintaining high productivity.
Solution Approach 2:
The patent replaces the mechanical field (force-based removal) with a pneumatic field (inflation-based separation). By using pneumatic pressure to create separation during curing, the system eliminates the need for high-force mechanical removal operations that cause surface abrasion.
3Manufacturing precision
If thermal expansion is used to create contact between the core and windings, then manufacturing precision is improved, but loss of time increases due to heating and cooling requirements
Solution Approach 1:
The patent replaces the thermal field (heating/cooling cycles) with a pneumatic field (inflation/deflation). Instead of relying on thermal expansion and contraction cycles, the invention uses pneumatic pressure to create and release contact, achieving the same manufacturing precision without the time-consuming thermal cycles.
Solution Approach 2:
The patent changes the physical parameter used for contact control from temperature (thermal expansion) to pressure (pneumatic inflation). This parameter change allows for rapid adjustment of contact conditions without the thermal inertia constraints, significantly reducing process time while maintaining manufacturing precision.
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 significantly shortens the overall process time, reduces resin coating damage, and extends the core's lifespan by minimizing mechanical stress, making it economically viable for repeated use.
Implementation Method 1
a sealing contact is temporarily created between the inner core and the stator's surfaces facing it by inflating/deflating one or more chambers within the core
Implementation Method 2
pouring liquid, two-component resin on the windings where it cures, forming a solid layer of coating
Implementation Method 3
The pre-heating that takes place in the oven therefore determines differential expansions
Data Source
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AI summary
A method with steps: - providing a moulding core (10) having elastic walls, enclosing an inner chamber (18, 20) with an opening (22), the opening (22) is connected to a valve (38). The mould comprises a lower portion (14) and an upper portion (16); - coupling the core (10) to a wound stator of an electric motor inside a housing (42), whereby the upper portion (16) is located inside of the stator and the lower portion (14) inside of the housing (42) below the windings (40); - inflating the inner chamber (18,20) through the opening (22), whereby the lower portion (14) seals inner surface of the housing (42) and the upper portion (16) contacts the stator windings (40); - pouring a resin to coat windings (40) outside of the core (10); - deflating through the opening (22) the inner chamber (18,20); - separating the core (10) from the stator.