Continuous Bar Winding Process for Electric Machines
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Solution Overview
Problem
Existing methods for making continuous bar windings for electric machines require complex and costly processes, such as numerous weldings and specialized cores, limiting versatility and electromagnetic efficiency.
Innovation Solution
A process involving a template with a circular array of slots and wire-guiding devices with multiple degrees of freedom to shape and insert continuous conductive bars, allowing them to pass through slots repeatedly without welding, enabling versatile winding configurations and reducing the need for specialized cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous conductive bars are shaped and inserted into slots repeatedly passing through the stator core, then the number of weldings is significantly reduced, but the process complexity increases due to the need for specialized shaping and insertion methods
Solution Approach 1:
The conductive bars are pre-shaped into a continuous configuration that allows them to repeatedly pass through the stator core slots. This preliminary shaping eliminates the need for multiple separate bars requiring welding, thereby reducing the number of weldings while maintaining a manageable process through advance preparation of the conductor geometry
Solution Approach 2:
The continuous conductive bar is divided into multiple segments or sections that each pass through different slots of the stator core. This segmentation allows the single continuous bar to serve multiple functions and create the necessary electrical connections without requiring physical weldings between separate bars
2Ease of manufacture
If pre-shaped continuous conductive bars are folded and inserted into segmented or flexible stator cores, then the winding process is simplified, but the electromagnetic performance deteriorates due to the specialized core requirements
Solution Approach 1:
The continuous conductive bar design is made universal by configuring it to work with standard rigid stator cores rather than requiring specialized segmented or flexible cores. The bar's continuous shape allows it to be adapted to conventional core structures, eliminating the need for specialized core types while maintaining ease of manufacture through the simplified single-piece conductor design
3Reliability
If numerous weldings are performed to connect conductive bars, then the electrical connections are achieved, but the manufacturing cost and time increase significantly
Solution Approach 1:
Multiple separate conductive bars that would traditionally require numerous weldings to connect are merged into a single continuous conductive bar. This combining eliminates the welding joints entirely, as the electrical continuity is maintained through the physical continuity of the single bar, thereby significantly reducing manufacturing time and cost while maintaining reliable electrical connections
Data Source
AI summary
A process for making a continuous bar winding (4) for an electric machine is described, comprising: a) a step of providing a template (10) having a template axis (X) and a circular array of slots (11) extended about said template axis (X), said circular array of slots having a number of slots equal to a number of slots of the stator or of the rotor of said electric machine, each slot (11) of said circular array having a first and a second open end face (11A, 11B) which are axially spaced from one another and a third open end face (11C), said third face (11C) being a longitudinal face extended between said first and second end faces (11A, 11B) b) a step of providing a conductive bar (20); c) a step of locking a locking portion (21) of said conductive bar; d) a step of inserting the conductive bar (20) into the slots (11) of said array and shaping the conductive bar (20) so that such conductive bar (20) repeatedly passes through the slots (11) of said array from the side of the first open end faces (11A) to the side of the second open end faces (11B) and vice versa, so that said bar (20) has a plurality of bar portions (20B, 20E, 20H) received in the slots (11) of said array and a plurality of connecting portions (20C, 20D; 20F, 20G) projecting beyond said first and second open end faces (11A, 11B), each of said connecting portions joining a pair of said bar portions (20B, 20E, 20H) received in the slots (11) of said array; in which said step d) comprises: d1) an operation of inserting a first bar portion (20B) of said plurality of bar portions into a respective slot (11) of said circular array of slots (11) through said third face (11C) of such slot (11); d2) an operation of shaping a first connecting portion (20C, 20D) of said plurality of connecting portions (20C, 20D; 20F, 20G); d3) an operation of inserting a second bar portion (20E) of said plurality of bar portions (20B, 20E, 20H) into a further slot (11) of said array, different from the slot (11) into which said first bar portion (20B) has been inserted, through said third face (11C) of the further slot (11); in which said first connecting portion (20C, 20D) joins said first and second bar portions (20B, 20E) projecting beyond the second end faces (11B) of the slots (11) in which said first and second bar portions (20B, 20E) have been inserted.