Electrotechnical Coil Shaping for Slot Fill Factor
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Solution Overview
Problem
Current methods for producing electrotechnical coils using casting technology face limitations in groove filling factor due to demolding gaps and surface quality issues, leading to inefficient use of space and increased mass in motors, with achievable filling factors typically around 70-80%.
Innovation Solution
A method involving casting and subsequent shaping of coils to displace the center of area of the cross-section in the radial direction, reducing or eliminating demolding chamfers, and using a multi-part shaping tool to compress the coil along the axis, thereby increasing the groove filling factor and simplifying the production process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If casting technology is used to produce coils, then groove filling factor increases significantly, but demolding gaps reduce the filling factor and affect heat dissipation
Solution Approach 1:
The coil is divided into multiple casting segments that can be produced separately and then joined. This segmentation allows each segment to be demolded independently with appropriate chamfers, while the final assembled coil achieves high groove filling factor by eliminating gaps between segments through precision joining techniques.
Solution Approach 2:
Demolding chamfers are intentionally designed into the casting mold before the actual coil production. These preliminary geometric features facilitate easy demolding while minimizing the impact on the final groove filling factor. The chamfers are optimized in advance to be as small as possible while still enabling successful demolding.
2Ease of manufacture
If demolding chamfers are provided on castings, then ease of demolding improves, but groove filling factor reduces and heat dissipation is negatively affected
Solution Approach 1:
Demolding chamfers are applied locally only at specific critical areas of the coil casting where demolding is most difficult, rather than uniformly across the entire coil surface. This localized approach minimizes the total volume lost to chamfers while ensuring successful demolding at key locations, thereby preserving the groove filling factor.
Solution Approach 2:
The geometry of demolding chamfers is optimized by varying their angle and depth parameters based on the specific local requirements of different coil sections. By adjusting these parameters, the design achieves the minimum necessary chamfer size for each location, reducing overall material loss while maintaining demolding feasibility.
3Ease of manufacture
If round wires are used for windings, then ease of winding improves, but space utilization is insufficient especially with conically designed coils
Solution Approach 1:
The invention transitions from traditional round wire windings to custom-shaped conductors with optimized cross-sectional geometries that match the coil's conical design. By changing the shape parameters of the conductors (e.g., using rectangular, trapezoidal, or custom profiles), the space utilization is significantly improved while the winding process remains feasible through adapted winding techniques.
Solution Approach 2:
The conductor cross-sections are designed with asymmetric shapes that better fit the conical coil geometry. Instead of uniform round wires, the conductors have varying cross-sectional dimensions that adapt to the changing radius of the conical coil, eliminating unused gaps and maximizing space utilization throughout the entire coil structure.
4Reliability
If insulation and discrete conductor distribution are provided, then electrical insulation is ensured, but filling factor is limited and cannot be calculated precisely
Solution Approach 1:
The invention merges the insulation function directly into the conductor design by applying insulation coatings or layers during the conductor manufacturing process itself. This integration eliminates the need for separate insulation layers and discrete conductor distributions, allowing for precise calculation of the filling factor while maintaining adequate insulation quality through the combined structure.
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 approach allows for a significant increase in groove filling factor, improved heat dissipation, and reduced material loss, enabling more compact and efficient motor designs with higher torque density, while also simplifying the manufacturing process and reducing production costs.
Implementation Method 1
Step A: casting an electrotechnical coil with at least one winding which runs about a coil axis
Implementation Method 2
shaping the coil, thereby changing the cross-section of the at least one winding, such that the center of area of the cross-section of the at least one winding is displaced at least partly in the radial direction relative to the coil axis
Data Source
AI summary
The invention relates to an electrotechnical coil, to a method for producing same, and to an electromagnet or an electric machine comprising at least one such coil. The aim of the invention is to produce and use an electrotechnical coil for achieving an increased slot fill factor reliably and easily in a reproducible and economical manner. This is achieved in that the method according to the invention has the steps: step A: casting an electrotechnical coil with at least one winding which runs about a coil axis; and step B: shaping the coil, thereby changing the cross-section Q, Q′ of the at least one winding, such that the centroid FS, FS′ of the cross-section Q, Q′ of the at least one winding is displaced at least partly in the radial direction R relative to the coil axis A.