Stator Neutral-Point Bus Bar Layout for Shorter Axial Length
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Solution Overview
Problem
The existing stator designs for rotating electric machines face challenges in size reduction due to increased axial length, particularly in configurations where neutral-point bus bars are connected to axial-direction wire end portions, leading to issues with size and efficiency.
Innovation Solution
The stator design incorporates a neutral-point bus bar connected to the coil end portion on the outer or inner side in a radial direction, with segment conductors' tip end portions joined in a circumferential direction, reducing axial height and using a plate-shaped bus bar with a folded portion to accommodate a temperature sensor, optimizing configuration and reducing tensile stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the neutral-point bus bar is connected to the axial-direction wire end portions, then the connection is simplified, but the axial length increases leading to size increase
Solution Approach 1:
The patent changes the connection dimension from axial direction to radial direction. The tip end portions of segment conductors extend in the radial direction and are joined together, while the neutral-point bus bar connects to these joined portions radially, avoiding axial length increase while maintaining connection functionality
2Ease of manufacture
If the connection portions protrude towards the side opposite the stator core, then the connection to phase windings is facilitated, but air bubbles are generated during resin sealing
Solution Approach 1:
Instead of having connection portions protrude towards the side opposite the stator core (which causes air bubble entrapment during resin sealing), the patent inverts the configuration so that connection portions are positioned on the stator core side or at the same axial level, allowing resin to flow properly without trapping air bubbles while still enabling electrical connection
3Ease of manufacture
If the bus bar structure is simplified, then manufacturing is easier, but temperature sensor accommodation becomes difficult
Solution Approach 1:
The patent applies nesting by placing the temperature sensor inside the folded portion of the bus bar structure. The bus bar is folded back to create a cavity that accommodates the temperature sensor, allowing the sensor to be integrated within the bus bar itself rather than requiring separate mounting space, thus maintaining manufacturing simplicity while enabling temperature monitoring functionality
Data Source
AI summary
In a stator, a stator winding is provided in a stator core and includes phase windings. A neutral-point bus bar is connected to a coil end portion of the stator winding in a radial direction thereof. The coil end portion includes first and second end portions that are joined together. The first tip end portion extends in a fixed direction in the circumferential direction. The second tip end portion extends in a direction opposite the fixed direction in the circumferential direction. The neutral-point bus bar includes a main body portion extending in the circumferential direction and connection portions extending in the radial direction from the main body portion. The connection portions are respectively connected to the phase windings in a state in which the connection portions do not protrude further towards a side opposite the stator core than the main body portion in the axial direction is.