Waterproof Magneto-Rotor Double Injection Moulding
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Solution Overview
Problem
Existing motor-pumps using rare-earth element magnets in synchronous electric motors face challenges in maintaining the magnetic properties of these magnets when exposed to water due to inadequate protection, leading to performance degradation.
Innovation Solution
A two-phase injection moulding process creates a double protective layer around the rare-earth element magnet rotor, with a first inner layer and a second outer layer, including annular protective barriers to prevent water ingress, ensuring the magnet is completely sealed and protected from humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single protective layer is used around the magnet, then the structure is simpler and manufacturing is easier, but water can penetrate through the layer and reach the magnet causing magnetic property loss
Solution Approach 1:
The protective layer is divided into two separate injection moulding phases, creating an inner protective layer and an outer protective layer. This segmentation ensures that water cannot penetrate through a single layer, as each layer provides independent protection. The two-layer structure addresses the waterproofing requirement while maintaining manufacturing feasibility through sequential processing.
Solution Approach 2:
The inner protective layer is formed first as a preliminary action before the outer protective layer is applied. This preliminary coating creates a base layer that provides initial protection, and the subsequent outer layer enhances this protection. The annular protective barriers are also formed during the first injection phase, preparing the structure for the second phase and ensuring complete sealing.
2Reliability
If the magnet is completely sealed with protective layers, then magnetic performance is maintained, but water may still seep between layers at interfaces
Solution Approach 1:
The annular protective barriers are formed during the first injection moulding phase as a preliminary sealing measure. These barriers create protruding sealing structures that extend into the second protective layer, establishing seal interfaces before the outer layer is applied. This preliminary formation of sealing barriers prevents water from reaching the magnet at the critical layer interfaces.
Solution Approach 2:
The annular protective barriers act as intermediary sealing elements between the inner and outer protective layers. These barriers, formed during the first injection phase, create physical protrusions that the second protective layer envelops, forming seal interfaces. The barriers serve as mediators that block water seepage paths at the layer interfaces, preventing water from penetrating to the magnet.
3Reliability
If a two-phase injection moulding process is used to create double protective layers, then complete waterproof sealing is achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The manufacturing process is segmented into two distinct injection moulding phases, with each phase forming a specific protective layer. The first phase creates the inner protective layer and annular barriers, while the second phase forms the outer protective layer. This segmentation allows for optimized processing parameters in each phase and enables complete waterproof sealing through the cumulative effect of both layers.
Solution Approach 2:
The first injection moulding phase performs preliminary actions by forming the inner protective layer and the annular protective barriers that will serve as sealing interfaces. This preliminary structure preparation enables the second phase to focus on forming the outer protective layer, with the seal interfaces already in place. The preliminary formation of barriers simplifies the overall two-phase process by pre-establishing the sealing architecture.
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 process effectively prevents water and humidity from reaching the magnet, maintaining its magnetic performance and structural integrity while being cost-effective and suitable for industrial-scale production.
Implementation Method 1
a first phase of coating the rotor with a first inner protective layer obtained by an injection moulding phase
Implementation Method 2
a second phase of coating the inner first protective layer of the rotor with a second outer protective layer obtained by a further injection moulding phase
Implementation Method 3
at least one annular protective barrier being shaped on at least one of the opposed end surfaces of the rotor during the first injection moulding phase, for preventing water or humidity from seeping between the first inner protective layer and the second outer protective layer
Data Source
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AI summary
The invention relates to a process for manufacturing a waterproof magneto-rotor (1) made of rare-earth elements, to be used in a synchronous electric motor having a rotor (2) with a permanent magnet and wherein the rotor (2) is solidly fixed to a shaft (3). The process comprises the following phases: a first phase of coating the rotor (2) with a first inner protective layer (12) obtained by an injection moulding phase; a second phase of coating the first inner protective layer (12) of the rotor (2) with a second outer protective layer (14) obtained by a further injection moulding phase; at least one annular protective barrier (15) being shaped on at least one or both the opposed end surfaces of the rotor (2) during the first injection moulding phase, for preventing water or humidity from seeping between the first inner protective layer (12) and the second outer protective layer (14).