Rotor Magnet Fixing by Trickle Resin Coating Without Demagnetization
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Solution Overview
Problem
Existing methods for fixing permanent magnets in rotor laminations of permanent excitation dynamoelectric machines are complex, costly, and prone to adhesive leakage and insufficient bonding due to capillary action, leading to inefficiencies and potential demagnetization.
Innovation Solution
A trickle coating process is employed to apply resin or adhesive to the outer circumference of a rotor lamination stack with inserted magnets, utilizing capillary action to ensure uniform adhesion between the magnets and pocket walls, eliminating the need for additional sealing and thermal curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is applied to fix permanent magnets in rotor laminations, then bonding strength is improved, but adhesive leaks uncontrollably into gaps between metal sheets due to capillary action
Solution Approach 1:
The adhesive is applied to the outer circumference of the rotor lamination stack before the magnets are fully inserted, allowing it to wick through the laminations via capillary action and position itself correctly before final magnet insertion occurs
Solution Approach 2:
Instead of trying to prevent capillary action from drawing adhesive into the gaps (which causes leakage), the invention inverts the approach by utilizing capillary action as the delivery mechanism to transport adhesive from the outer circumference through the laminations to the magnet insertion points
2Strength
If adhesive is applied to fix permanent magnets in rotor laminations, then bonding strength is improved, but bonding precision deteriorates due to insufficient adhesive in the gap
Solution Approach 1:
The adhesive is pre-applied to the outer circumference of the rotor lamination stack, allowing it to wick through the laminations via capillary action and position itself correctly before final magnet insertion occurs
Solution Approach 2:
The invention utilizes capillary action (a fluid dynamics phenomenon) to transport the adhesive through the laminations, replacing the need for mechanical injection or vacuum systems to deliver adhesive to the bonding location
3Strength
If encapsulation with reactive resin is used to fix permanent magnets, then bonding strength is improved, but processing time increases due to thermal curing requirements
Solution Approach 1:
The invention extracts the thermal curing step from the bonding process by using adhesive that cures at ambient temperature, separating the bonding function from the thermal treatment function
Solution Approach 2:
The invention uses a single-application adhesive system that cures at ambient temperature, eliminating the need for expensive and time-consuming oven curing cycles while achieving sufficient bonding strength
4Strength
If high temperature thermal treatment is applied for curing, then bonding strength is improved, but permanent magnets suffer partial demagnetization
Solution Approach 1:
The invention extracts the thermal curing step from the bonding process by using adhesive that cures at ambient temperature, separating the bonding function from the thermal treatment function
Solution Approach 2:
The invention changes the curing temperature parameter from high temperature (140°C) to ambient temperature, thereby eliminating the demagnetization effect while maintaining bonding effectiveness
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 provides a simple, cost-effective solution with uniform magnet fixation, preventing adhesive leakage and demagnetization, suitable for high temperatures, and reducing operational vibrations.
Implementation Method 1
utilizing capillary action to ensure uniform adhesion between the magnets and pocket walls
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a method for fixing permanent magnets (9) in rotors (4) of permanent magnet synchronous machines by means of a trickling process by the following steps: - Stacking (30), in particular stamping stacking of a laminated core (6) of the rotor (4), - Rotationally fixed connection of the laminated core (6) to a shaft (8), - Axial insertion of permanent magnets (15) in substantially axially extending recesses (11) of the laminated core (6), - The laminated core (6) equipped with permanent magnets (15) is supplied with resin or hardener at least on the outer diameter by means of at least one axially movable nozzle while rotating about its axis (7), so that the resin or adhesive (47) is distributed uniformly at least over the outer surface in adhesive gaps (18, 20) between the permanent magnet (15) and the inside of the pocket (12), as well as between the laminations (5) in the radially outer region of the laminated core (6).