Rotary Electric Machine Bus Bar Cooling
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Solution Overview
Problem
Existing rotary electric machines with distributed winding stators suffer from inadequate cooling performance due to limited refrigerant contact with coils, despite efforts to reduce size and increase power.
Innovation Solution
Incorporating a bus bar on the inner diameter side of the stator, which occludes radial clearances between coil ends and guides refrigerant to ensure sufficient contact with the coils, enhancing cooling performance without increasing machine size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coil ends are radially disposed with empty spaces between them for refrigerant flow, then refrigerant can pass through, but cooling performance is insufficient due to limited refrigerant-coil contact
Solution Approach 1:
A refrigerant guide member is introduced as an intermediary component between the refrigerant flow path and the coil ends. This guide member actively directs and channels the refrigerant to ensure comprehensive contact with the coil ends, transforming the passive flow through empty spaces into an active cooling process with optimized refrigerant-coil interaction.
Solution Approach 2:
The refrigerant guide member creates localized high-velocity refrigerant flow paths that directly impinge on the coil ends. By concentrating the refrigerant flow in specific regions where it contacts the coil ends most effectively, the local cooling quality is enhanced, ensuring adequate cooling performance in critical areas.
2Power
If distributed winding with rectangular coils is used, then space factor increases and power increases, but cooling performance deteriorates due to limited refrigerant access
Solution Approach 1:
The refrigerant guide member serves as a mediator that bridges the gap between the refrigerant supply system and the densely packed rectangular coils. It penetrates through the coil assembly to deliver refrigerant directly to the coil ends, enabling effective cooling of the high-power distributed winding configuration without requiring changes to the coil geometry itself.
3Volume of moving object
If machine size is reduced, then compactness improves, but cooling performance worsens due to insufficient refrigerant flow paths
Solution Approach 1:
The refrigerant guide member extends the cooling approach into the axial dimension by penetrating through the coil ends from the axial direction. This dimensional transition allows refrigerant to access the coil ends directly, providing effective cooling paths within the compact radial space without increasing the overall machine volume.
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
The solution significantly improves cooling performance by ensuring the refrigerant comes into extensive contact with the coil ends, thereby enhancing the thermal management of the rotary electric machine.
Implementation Method 1
a bus bar which, being disposed on the inner diameter side of the plurality of coil ends so as to occlude the clearances between the plurality of coil ends, guides a refrigerant, which is supplied from the radial direction of the stator, to the plurality of coil ends
Implementation Method 2
The stator also includes a bus bar which... guides a refrigerant... to the plurality of coil ends... ensuring the refrigerant comes into extensive contact with the coil ends, thereby enhancing the thermal management
Data Source
AI summary
To provide a rotary electric machine which is improved in cooling performance. The rotary electric machine includes a rotor; and a stator which, being disposed opposite the rotor, has a stator core having a plurality of slots therein and a stator winding wound in the plurality of slots, wherein the stator has a plurality of coil ends which are formed protruding from an axial end face of the stator core and between adjacent ones of which is provided a radial clearance passing through from the inner diameter side to the outer diameter side, and wherein the stator includes a bus bar which, being disposed on the inner diameter side of the plurality of coil ends so as to occlude the clearances between the plurality of coil ends, guides a refrigerant, which is supplied from the radial direction of the stator, to the plurality of coil ends.