Rotating Electric Machine Stator Bus Bar Segmentation
Solution Overview
Problem
The existing rotating electric machines with divided bus bars for phase and neutral point connections face challenges in reducing the stator's outer-diameter dimension while maintaining adequate cooling performance for windings, as the bus bars cover coil end portions, reducing cooling efficiency when positioned on one end side, and increase the stator diameter when not covering the other end side.
Innovation Solution
A rotating electric machine design featuring a stator core with windings for U, V, and W phases, where one end of each winding is connected to a power supply bus bar on one end side, and the other ends extend towards each other to form a coil group, with a bobbin providing insulation and a slit for refrigerant flow to improve cooling, reducing the stator's outer-diameter dimension and enhancing cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If bus bars for phase connection and neutral point connection are divided and provided on both end sides in the axial direction of the stator core, then the outer-diameter dimension of the stator can be reduced, but the coil end portions are covered by the bus bars, resulting in reduced cooling performance
Solution Approach 1:
The patent divides the bus bar configuration into two separate functions: power supply bus bars for phase connection are provided on one end side, while the other ends of windings for different phases are mutually connected on the other end side. This segmentation allows each end side to have specialized functions, reducing the outer-diameter dimension while preventing bus bars from covering coil end portions, thus maintaining cooling performance.
2Temperature
If bus bars for phase connection and neutral point connection are provided on only one end side in the axial direction of the stator core, then coil end portions on the other end side are not covered by bus bars allowing refrigerant to cool them, but the outer-diameter dimension of the stator increases
Solution Approach 1:
The patent utilizes the axial dimension to separate different electrical connection functions. By providing power supply bus bars on one end side and mutual connection of winding ends on the other end side, the design effectively uses the axial direction to resolve the conflict between cooling performance and outer-diameter dimension, allowing refrigerant flow paths to remain unobstructed while maintaining compact stator dimensions.
3Length of stationary object
If bus bars cover coil end portions, then the stator outer-diameter dimension is reduced, but the refrigerant cannot directly cool the coil end portions, reducing cooling efficiency
Solution Approach 1:
The patent extracts the neutral point connection function from the power supply bus bar configuration. By having the other ends of windings for different phases mutually connected separately on the other end side, the design removes the obstruction of bus bars from the coil end portions, allowing refrigerant to directly contact and cool the coil end portions, thus maintaining high cooling efficiency while achieving compact stator dimensions.
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
This design effectively reduces the stator's outer-diameter dimension while improving the cooling performance of the windings by allowing refrigerant to directly cool the coil end portions and maintaining reliable insulation between adjacent windings.
Implementation Method 1
a bobbin insulating the stator core and each winding from each other
Implementation Method 2
a slit for refrigerant flow to improve cooling
Implementation Method 3
refrigerant to directly cool the coil end portions
Data Source
AI summary
A coil group 23G is composed of windings 23U to 23W for U phase, V phase, and W phase. One ends 23U1 to 23W1 of the windings for the respective phases composing the coil group 23G are connected to respective power supply bus bars 25U to 25W, and the other ends 23U2 and 23W2 of the windings for the phases positioned at both ends in the circumferential direction in the coil group 23G extend toward the other end 23V2 of the winding for the rest of the phases, whereby the other ends 23U2 to 23W2 of the windings for the respective phases are mutually connected.