Rotary Machine Cooling Structure with Balanced Coolant Distribution
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Solution Overview
Problem
Existing cooling structures for rotary electric machines face challenges in achieving uniform cooling performance across both axial directions due to differences in coil end portion sizes and shapes, leading to uneven coolant distribution and assembly difficulties, particularly in tight spaces like electric vehicles.
Innovation Solution
A cooling structure with separate coolant chambers for lead and non-lead side coil end portions, connected via a communicating path to balance coolant amounts and pressures, and strategically positioned coolant supply ports to facilitate easy assembly and mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling jacket is provided on each side of the stator in the axial direction with separate oil supply ports, then cooling coverage is improved, but coolant distribution becomes uneven due to differences in coil end portion sizes
Solution Approach 1:
The patent applies asymmetry by providing different oil supply port configurations for the lead side and non-lead side cooling jackets. The lead side cooling jacket has a first oil supply port with a larger diameter than the second oil supply port on the non-lead side, matching the asymmetric size difference between coil end portions. This asymmetric design enables uniform coolant distribution despite the asymmetric coil structures.
Solution Approach 2:
The patent applies local quality by tailoring the oil supply port dimensions to the specific cooling needs of each coil end portion. The lead side coil end portion, being larger, receives coolant through a larger diameter port, while the smaller non-lead side receives coolant through a smaller port. This localized adaptation of port size optimizes cooling performance for each specific region.
2Temperature
If oil supply ports are formed on both sides in the axial direction, then cooling access is improved, but assembly difficulty increases in tight spaces
Solution Approach 1:
The patent applies merging by combining the oil supply functions into a single side configuration. Instead of requiring separate oil supply ports on both axial sides, the design provides both oil supply ports on the same side, allowing coolant supply from a single access point. This reduces assembly complexity in tight spaces while maintaining effective cooling of both coil end portions.
3Temperature
If coolant chambers are formed for each coil end portion, then cooling precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the cooling jacket to serve multiple functions simultaneously. The single cooling jacket structure provides both the first coolant chamber for the lead side coil end portion and the second coolant chamber for the non-lead side coil end portion, while also incorporating both oil supply ports and the communicating path. This multi-functional design achieves precise cooling without proportionally increasing structural complexity.
Solution Approach 2:
The patent applies the nested doll principle by placing the communicating path inside the cooling jacket structure. The communicating path is integrated within the walls of the cooling jacket, allowing it to connect the two coolant chambers without adding external complexity. This nested configuration maintains compactness while enabling balanced coolant distribution.
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
Ensures uniform cooling performance across both axial directions, improves assembly and mountability of rotary electric machines, particularly in constrained spaces like electric vehicles, by balancing coolant distribution and simplifying conduit connections.
Implementation Method 1
the coil end portions of the coils are cooled by coolant such as cooling oil
Implementation Method 2
Cooling oil is supplied so as to flow inside the jacket, such that the coil is cooled by the entire coil end portions contacting the cooling oil
Data Source
AI summary
A cooling structure for a rotary electric machine uses coolant to cool coil end portions that protrude outward, one from each end surface of a stator core, in a stator that includes a stator core and coils that are wound in a circumferential direction of the stator core. This cooling structure includes a lead side cover member that covers a lead side coil end portion to which a lead wire that supplies electricity to the coils is connected, and forms a first coolant chamber within which coolant is stored; and a non-lead side cover member that covers a non-lead side coil end portion positioned opposite the lead side coil end portion in the axial direction, and forms a second coolant chamber within which coolant is stored. A coolant communicating path is provided that communicates the first and second coolant chambers in a manner that enables coolant to flow therebetween.