Rotary Electric Machine Dual-Side Stator Cooling
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Solution Overview
Problem
Existing rotary electric machines face challenges in achieving uniform cooling of stator coils due to temperature distribution issues, particularly between coil ends, leading to increased coolant flow requirements that result in weight, energy consumption, and cost increases.
Innovation Solution
A dual cooling mechanism is implemented, where a first cooling mechanism supplies coolant from the outer circumferential side and a second cooling mechanism supplies coolant from the inner circumferential side, with a higher supply amount to the close-side coil end, ensuring effective cooling of both close-side and open-side coil ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant dropping type cooling structure is used, then cooling is provided to the stator, but the lower side of the coil cannot be cooled effectively, resulting in large temperature distribution
Solution Approach 1:
The patent transitions from a single-direction (top-down) cooling approach to a multi-directional cooling system. The first cooling mechanism cools from the outer circumferential side while the second cooling mechanism cools from the inner circumferential side, creating cooling from multiple dimensions simultaneously. This dimensional change ensures comprehensive cooling coverage including the previously unreachable lower side of the coil.
Solution Approach 2:
The cooling system is segmented into two distinct cooling mechanisms with different functions. The first cooling mechanism handles outer circumferential cooling while the second cooling mechanism handles inner circumferential cooling. This segmentation allows each mechanism to be optimized for its specific region, improving overall cooling uniformity without requiring excessive coolant flow from a single mechanism.
2Reliability
If pump capacity is increased to ensure cooling performance, then cooling performance is improved, but weight, energy consumption, and cost increase
Solution Approach 1:
Instead of increasing pump capacity excessively to cool all regions uniformly, the patent applies partial cooling actions from two different directions. The first cooling mechanism provides cooling from the outer circumferential side while the second cooling mechanism provides cooling from the inner circumferential side. This partial action approach from multiple sources achieves comprehensive cooling without requiring a single oversized pump.
Solution Approach 2:
The cooling system achieves multi-functionality by implementing two cooling mechanisms that work together. The first cooling mechanism and second cooling mechanism serve complementary functions, with the second mechanism specifically addressing the inner circumferential region that the first mechanism cannot reach effectively. This multi-functional approach ensures complete cooling coverage while maintaining reasonable pump capacity.
3Temperature
If coolant flow is increased to cool the close-side coil end, then cooling performance is improved, but the number of coolant dropping pipes and system complexity increases
Solution Approach 1:
The patent extracts the cooling function for the close-side coil end from the first cooling mechanism and assigns it to the second cooling mechanism. By taking out this specific cooling task and assigning it to a dedicated mechanism (the second cooling mechanism that supplies coolant from the inner circumferential side), the system achieves effective cooling of the close-side coil end without requiring additional dropping pipes in the first cooling mechanism.
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 configuration allows for improved cooling performance by actively spreading coolant to both coil ends, reducing the need for increased coolant flow and pump capacity, thereby minimizing weight, energy consumption, and costs while maintaining efficient temperature regulation.
Implementation Method 1
a first cooling mechanism which supplies a coolant to the coil from an outer circumferential side of the stator
Implementation Method 2
supplies a coolant to the coil from an outer circumferential side of the stator
Implementation Method 3
a second cooling mechanism which supplies a coolant to the coil from an inner circumferential side of the stator
Implementation Method 4
supplies a coolant to the coil from an inner circumferential side of the stator
Data Source
AI summary
A rotary electric machine includes a rotor, a stator which is disposed on an outer circumferential side of the rotor and includes a stator core and a coil, a first cooling mechanism which supplies a coolant to the coil from an outer circumferential side of the stator, and a second cooling mechanism which supplies a coolant to the coil from an inner circumferential side of the stator. The coil includes a plurality of segment cods, each including a pair of leg portions, and a connection portion connecting one end sides of the leg portions. A close-side coil end constituted by the connection portion and an open-side coil end constituted by the lea portions are provided on respective end sides of the stator core. A supply amount of the coolant supplied from the second cooling mechanism is larger to the close-side coil end than to the open-side coil end.