IPM Rotor Magnet Positioning With Laminated Foam Adhesive Layers
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Solution Overview
Problem
The existing rotors for IPM motors face issues with insufficient adhesion of adhesive sheets to the rotor core, leading to inadequate positioning accuracy of the rotor magnet, which affects the motor's performance.
Innovation Solution
A rotor configuration featuring a positioning member with laminated foam layers, including a magnet-side foam layer with adhesive and a rotor core-side foam layer, positioned between the rotor magnet and the magnet insertion hole, along with protrusions to secure the magnet in place, ensuring accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single adhesive layer is used in the adhesive sheet, then the permanent magnet can be adhered to the rotor core, but the adhesion to the inner surface of the magnet insertion hole is insufficient and positioning accuracy is inadequate
Solution Approach 1:
The adhesive sheet is segmented into three distinct layers: a first adhesive layer for bonding to the permanent magnet, a base material layer providing structural support, and a second adhesive layer with foamability for bonding to the magnet insertion hole. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between adhesion strength and positioning accuracy.
Solution Approach 2:
The adhesive sheet uses composite material structure combining different adhesive layers with a base material layer. The first adhesive layer provides strong bonding to the magnet, the base material layer provides mechanical strength and dimensional stability, and the second adhesive layer with foamability provides expansion capability for filling gaps and enhancing adhesion to the magnet insertion hole surface.
2Reliability
If the adhesive sheet is expanded by heating, then the adhesion to the magnet insertion hole is improved, but the base material layer without expansion capability limits the degree of adhesion
Solution Approach 1:
The adhesive sheet applies local quality by making only the second adhesive layer possess foamability for expansion, while the base material layer and first adhesive layer maintain their respective functions. This localized expansion capability allows the adhesive sheet to achieve strong adhesion to the magnet insertion hole without requiring the entire structure to be complex.
3Manufacturing precision
If a foam piece is attached to the permanent magnet, then positioning is improved, but the adhesion to the magnet insertion hole surface remains insufficient
Solution Approach 1:
The invention merges the positioning function and adhesion function into a single integrated adhesive sheet structure. The laminated configuration of multiple adhesive layers and base material layer combines the positioning capability (through controlled expansion) with strong adhesion to the magnet insertion hole surface, eliminating the need for separate foam pieces and achieving both positioning accuracy and adhesion strength simultaneously.
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 rotor magnet is easily and accurately positioned, enhancing the motor's performance by maintaining strong adhesion and stability even under centrifugal forces.
Implementation Method 1
a first foam layer (55) containing an adhesive that adheres to the rotor magnet (22)
Implementation Method 2
a second foam layer (56) in contact with the inner surface of the magnet insertion hole (24) of the rotor core (21)
Implementation Method 3
the adhesive sheet is expanded and cured to fix the permanent magnet in the slit hole
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A rotor (2) includes a columnar rotor core (21) that has a magnet insertion hole (24) penetrating the rotor core (21) in the axial direction, a rotor magnet (22) inserted into the magnet insertion hole (24), and a positioning member (23) that positions the rotor magnet (22) in the magnet insertion hole (24). The positioning member (23) includes a first foam layer (55) containing an adhesive (55a) that adheres to the rotor magnet (22), a second foam layer (56) in contact with an inner surface of the magnet insertion hole (24) of the rotor core (21), and a base material layer (57) located between the first foam layer (55) and the second foam layer (56). The first foam layer (55), the second foam layer (56), and the base material layer (57) are laminated and located between the rotor magnet (22) and the inner surface of the magnet insertion hole (24).