Liquid-Crystal Polymer Fixing Agent for Rotor Core Magnets
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Solution Overview
Problem
Conventional rotor core manufacturing processes for rotating electrical machines are complex and prone to stress-induced deformation due to the use of thermosetting resins and multiple heating and cooling steps, which complicate the process and increase the risk of damage to thin parts.
Innovation Solution
The use of liquid-crystal polymer as a fixing agent with a melt viscosity of less than or equal to 8.0 pascal-seconds, which hardens at ordinary temperature, eliminating the need for preheating and cooling steps and reducing stress on permanent magnets during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermosetting resin (epoxy resin) is used as the fixing agent, then the permanent magnets are firmly fixed in the accommodating slots, but heating and cooling steps are required which complicate the manufacturing process
Solution Approach 1:
The patent changes the chemical properties of the fixing agent from thermosetting resin to thermoplastic resin, which eliminates the need for heating and cooling steps during the fixing process. This parameter change in material properties resolves the contradiction by maintaining fixing strength while simplifying the manufacturing process.
Solution Approach 2:
The patent utilizes the phase transition properties of thermoplastic resin, which becomes fluid at elevated temperatures for easy injection and solidifies at ordinary temperatures for firm fixing. This phase transition mechanism allows the fixing agent to provide strong fixation without requiring the complex heating and cooling cycles needed for thermosetting resins.
2Reliability
If thermosetting resin is used as the fixing agent, then the permanent magnets are securely fixed, but a large number of heating and cooling steps are required
Solution Approach 1:
The patent changes the material parameters of the fixing agent from thermosetting to thermoplastic resin, which fundamentally alters the curing mechanism. This eliminates the lengthy heating and cooling cycles required for thermosetting resins, significantly reducing manufacturing cycle time while maintaining reliable fixation through the thermoplastic resin's solidification process.
Solution Approach 2:
The patent exploits the reversible phase transition of thermoplastic resin between solid and liquid states. The resin is heated to become fluid for injection, then naturally solidifies at ambient temperature to secure the permanent magnets. This phase transition approach eliminates the need for prolonged heating and cooling steps, reducing manufacturing time while ensuring reliable fixation.
3Ease of manufacture
If the rotor core and permanent magnets are heated and cooled during manufacturing, then the thermosetting fixing agent can be properly applied, but stress concentrates on the permanent magnets and thin parts causing deformation
Solution Approach 1:
The patent changes the material properties of the fixing agent from thermosetting to thermoplastic resin, which eliminates the need for high-temperature heating and subsequent cooling steps. This parameter change resolves the contradiction by enabling proper application of the fixing agent through simple heating while avoiding the thermal stress that causes deformation of thin parts and permanent magnets.
Solution Approach 2:
The patent utilizes the phase transition of thermoplastic resin, which requires minimal heating to become fluid for injection and then naturally solidifies at or near ambient temperature. This phase transition process applies minimal thermal stress compared to thermosetting resins, thereby preventing deformation of thin parts and permanent magnets while still enabling effective application of the fixing agent.
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 simplifies the manufacturing process by eliminating heating and cooling steps, reducing stress on thin parts, and preventing deformation, while ensuring efficient filling of the fixing agent between the rotor core and permanent magnets.
Implementation Method 1
A liquid-crystal polymer, which hardens at ordinary temperature, is used as the fixing agent 15
Implementation Method 2
the fixing agent 15 is injected into a space between an inner surface of each accommodating slot 13 and an outer surface of the corresponding permanent magnet 14
Data Source
AI summary
A core has accommodating slots each accommodating a permanent magnet. A fixing agent is injected into the space between the inner surface of each accommodating slot and the outer surface of the associated permanent magnet. A liquid-crystal polymer is used as the fixing agent. More specifically, liquid-crystal polyester is used.