Cantilevered Motor Coil Eccentric Rolling Shaping
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Solution Overview
Problem
Existing methods for producing rotating electrical machines with cantilevered coils face inefficiencies due to high centrifugal forces, limited coil length, and ineffective conductor utilization, which restrict the size and efficiency of the machines.
Innovation Solution
A method involving winding a motor coil around a cylindrical inner part that completely surrounds it, followed by shaping and compacting the coil using an eccentric rolling process to create a precise air gap, allowing for efficient production and high copper filling, thereby enhancing power density and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bell-shaped coils are used with conventional winding methods, then the coil structure is self-supporting, but the conductor utilization is ineffective and the coil length is limited due to high centrifugal forces
Solution Approach 1:
The patent inverts the conventional approach by using a mandrel as the supporting structure during winding, then removing it to create a self-supporting coil. This allows the coil to be wound with proper support without requiring the mandrel to remain, achieving both ease of manufacture and improved conductor utilization.
Solution Approach 2:
The patent segments the coil winding process into distinct phases: winding around a mandrel, removing the mandrel, and allowing the coil to self-support. This segmentation enables better conductor arrangement and utilization while maintaining structural integrity.
2Stability of the object's composition
If the coil is wound onto a sleeve or mandrel with intermediate baking, then the coil maintains shape during winding, but the manufacturing process is complex and time-consuming
Solution Approach 1:
The patent extracts the mandrel from the final coil structure, using it only during the winding process. This allows the coil to be shaped during winding without requiring complex intermediate baking or finishing processes, as the mandrel provides temporary support that is later removed.
Solution Approach 2:
The mandrel provides preliminary support during winding, ensuring proper coil shape formation before the coil is removed and allowed to self-support. This preliminary action eliminates the need for subsequent shaping operations.
3Power
If the effective conductor is increased by axial extension of the machine, then the power density increases, but the centrifugal forces become too high for single-sided support
Solution Approach 1:
The patent inverts the support approach by using a mandrel during winding that can support longer coils, then removing it to allow the coil to self-support. This enables the construction of longer coils with higher power density that would be impossible to support in a single-sided configuration during the winding process.
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 method results in a more efficient and compact motor coil design with improved power density and reduced manufacturing tolerances, enabling longer coil lengths and higher efficiency in rotating electrical machines.
Implementation Method 1
Winding is carried out successively in various layers, wherein after each layer, the wire is fixed by way of heating (intermediate baking)
Implementation Method 2
The final shaping process is carried out by way of the so-called finish baking
Implementation Method 3
an expanding mandrel or a pressure pad is used which acts outwardly in the radial direction onto the coil and presses the latter against an outer mould
Data Source
AI summary
A method for producing rotating electrical machines having a motor coil produced in a cantilevered manner for motors or generators, wherein the coil already surrounds the inner part during the manufacturing process, i.e. is pre-assembled, and this is also used as an aid for coil shaping during the production of the coil, includes a first step, in which the motor coil is wound in a stepwide process between two end faces over the magnetic inner part and completely surrounds the inner part, a second step, in which the shaping of the motor coil is carried out by pressing the winding wires by moving the shaft with the surface of the inner part against the inner side of the motor coil, in particular by eccentrically rolling off of the latter and pressing it against an abutment, and a third step, in which the pressed motor coil is baked by way of applying heat. Also provided is a rotating electrical machine.