Electric Machine Stator Welded-Side Pitch Narrowing
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Solution Overview
Problem
Conventional electric rotating machines experience reduced vibration-resistance at the coil end on the welded side due to a large distance between the stator core and welded portions, especially when conductor segments are thick and heavy, carrying a large current.
Innovation Solution
The electric rotating machine incorporates a stator winding with U-shaped conductor segments connected in series by welding, featuring a narrower slot pitch on the welded side opposite to the turn portions, and utilizes overlapped wire wrapping sections with crossover wires to connect the segments, reducing the axial length and improving vibration-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pitch of the coil end on the welded side is set to 180 degrees (equal to N-S magnetic pole pitch), then the structure is simple and easy to manufacture, but the distance between the end surface of the stator core and each welded portion becomes large, lowering the vibration-resistance of the coil end
Solution Approach 1:
The patent applies different pitch values to different parts of the stator winding. Specifically, the welded side slot pitch is set to be narrower than the N-S magnetic pole pitch (180 degrees), while other portions may maintain different pitch characteristics. This local differentiation allows the welded portions to be positioned closer to the stator core end surface, improving vibration-resistance without uniformly complicating the entire winding structure
Solution Approach 2:
The patent changes the pitch parameter from the conventional 180 degrees (equal to N-S magnetic pole pitch) to a narrower value for the welded side slot pitch. This parameter modification directly addresses the vibration-resistance issue by reducing the distance between welded portions and the stator core end surface, while maintaining manufacturability through a controlled deviation from the standard pitch
2Power
If conductor segments are made thick and heavy to carry a large current, then the current-carrying capacity increases, but the distance between the end surface of the stator core and welded portions increases further, exacerbating the vibration-resistance problem
Solution Approach 1:
The patent applies a narrower welded side slot pitch specifically to regions with thick conductor segments. This local adaptation ensures that even when heavy conductors are used for high current capacity, the welded portions remain positioned closer to the stator core end surface, maintaining vibration-resistance despite the increased conductor dimensions
3Strength
If the pitch of the coil end on the turn portions side is set narrower than the N-S magnetic pole pitch (e.g., 150 degrees), then the rigidity of the coil end is improved and vibration-resistance is enhanced, but the pitch of the coil end on the welded side remains at 180 degrees, creating an imbalance that reduces overall vibration-resistance
Solution Approach 1:
The patent extends the application of narrower pitch to both the turn portions side and the welded side. By setting the welded side slot pitch narrower than the N-S magnetic pole pitch, the patent creates a balanced configuration where both ends of the conductor segments benefit from improved rigidity and vibration-resistance, eliminating the imbalance present in conventional designs
Data Source
AI summary
The stator of the electric rotating machine includes a stator winding constituted of a plurality of U-shaped conductor segments each including a turn portion and two straight portions, the U-shaped conductor segments being connected in series by welding at welded portions formed in ends of the straight portions, and a stator core formed with slots, the straight portions of each U-shaped conductor segment being accommodated in corresponding two of the slots. The welded side slot pitch as an interval of the corresponding two of the slots on the side opposite to the turn portions is narrower than the N-S magnetic pole pitch of the rotor. The stator winding includes overlapped wire wrapping sections each constituted of the U-shaped conductor segments accommodated in the corresponding two of the slots, and crossover wires disposed on the side of the welded portions for connecting the overlapped wire wrapping sections.