Rotary Electric Machine Bus Bar Phase Assembly
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Solution Overview
Problem
Existing rotary electric machines face issues with incorrect phase assembly of bus bars, leading to connection failures and increased manufacturing complexity due to the large number of welding processes required for connecting concentrated winding coils and terminal members.
Innovation Solution
The design incorporates bus bars formed in arc or annular forms, with a holder that engages specific bus bar engagement portions to ensure correct phase assembly and reduce the likelihood of connection failures, and includes crossover wire portions to connect winding start and end portions, reducing the number of welding processes needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bus bars are assembled on the stator without engagement portions, then the assembly process is simple, but the bus bar may be assembled in a wrong phase leading to connection failure
Solution Approach 1:
The bus bar engagement portion acts as an intermediary mechanical feature that mediates between the bus bar and stator core. This engagement portion (protrusion or recess) physically guides the bus bar into the correct phase position during assembly, preventing wrong-phase assembly while maintaining a relatively simple assembly process.
2Strength
If concentrated winding coils are connected to terminal members with two coil terminals each, then the connection is robust, but the number of welding processes increases significantly
Solution Approach 1:
The patent merges the two separate coil terminals (winding start and winding end) into a single integrated terminal member structure. By combining the terminal functions and using a single terminal member per phase, the number of welding operations is reduced from multiple welds per phase to fewer welds, while maintaining robust electrical and mechanical connections.
Data Source
AI summary
A rotary electric machine includes a rotor core fixed at a rotation axis, a stator core arranged facing the rotor core and including a plurality of teeth, a plurality of windings wound at the plurality of teeth of the stator core, a plurality of winding connection terminals connected to respective ends of the plurality of windings, a plurality of bus bars connected to the plurality of winding connection terminals, each of the plurality of bus bars being formed in either an arc form or an annular form, and a bus bar holder holding the plurality of bus bars in a laminated state and including a holder engagement portion engaging with a bus bar engagement portion which is provided at least at one of the plurality of bus bars.