Permanent Magnet Motor Isolating Layer Water Leakage
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Solution Overview
Problem
Current draining pumps with AC permanent magnet synchronous motors face issues of water leakage and rusting due to the lack of effective sealing between the iron core and rotor cavity, leading to coil burning and reduced electromagnetic efficiency.
Innovation Solution
A method involving injection molding to create a U-shaped iron core with a groove on its internal concave surface, where an isolating thin layer with a root is embedded, forming a tight seal between the iron core and rotor barrel, preventing water ingress and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the iron core is not isolated from the rotor by a protective material, then the manufacturing process is simple, but water enters the rotor cavity and causes rusting of the iron core
Solution Approach 1:
The patent introduces an isolating thin layer (plastic material) as an intermediary substance between the iron core and the rotor cavity. This thin layer serves as a mediator that prevents direct contact between water in the rotor cavity and the iron core, thereby eliminating rusting without requiring complex manufacturing processes. The isolating layer is applied directly to the iron core surface, maintaining manufacturing simplicity while providing reliable water protection.
2Loss of energy
If the internal surface of the rotor cavity is formed by the internal concave surface of the iron core and the rotor barrel together, then the electromagnetic efficiency is improved, but water leaking into the rotor cavity seeps into the iron core through the internal concave surface
Solution Approach 1:
The isolating thin layer acts as a protective intermediary coating on the internal concave surface of the iron core. This allows the rotor cavity to maintain its close-fit structure with the iron core for high electromagnetic efficiency, while simultaneously preventing water from penetrating through the concave surface to the iron core. The thin layer is sufficiently thin to maintain magnetic circuit efficiency but sufficient to provide water protection.
3Reliability
If a stainless steel barrel is provided in the rotor barrel to isolate the internal concave surface of the iron core, then water contact with iron core is prevented, but the manufacturing process becomes complicated and cost increases
Solution Approach 1:
Instead of using a expensive and complex stainless steel barrel structure, the patent employs a thin plastic isolating layer that is cost-effective and simple to manufacture. This thin layer provides sufficient protection against water ingress without requiring complex assembly or expensive materials, thereby reducing both manufacturing complexity and cost while maintaining reliable protection.
4Reliability
If the isolating thin layer is applied on the pole arc part of the iron core, then water is prevented from contacting the iron core, but the air gap for the magnetic circuit increases
Solution Approach 1:
The isolating thin layer is selectively applied only on the pole arc part of the iron core where water contact is most critical, rather than covering the entire iron core surface. This localized application provides targeted protection against water ingress while minimizing the increase in air gap thickness, thereby maintaining electromagnetic efficiency. The thin layer thickness is optimized to be as small as possible while still providing effective water protection.
Data Source
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AI summary
A permanent magnet synchronous motor with an integrated pump body and its preparation method are provided. The preparation method comprises steps in the following order: 1) performing an injection molding process for the first time on a coil, which is wound on a coil former, to form a coil sealing part for sealing the coil; 2) assembling an iron core in the sealed coil and performing the injection molding process for the second time on them to form a pump body part with a rotor barrel, wherein, the rotor barrel is formed by conducting the injection molding process based on the iron core, and an isolating thin layer is formed at a polar arc part of the iron core to isolate the iron core from a rotor cavity in the rotor barrel. In this invention, since the iron core and the coil are sealed in an injection molding container and the isolating thin layer isolates the polar arc part from the rotor cavity, a good electromagnetic property of the motor is ensured and the water leakage problem is solved.