Rotary Electric Machine Cooling Pressure Balance
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Solution Overview
Problem
Existing rotary electric machine cooling systems in hybrid vehicles face pressure differences between motor and generator housings, leading to uneven cooling oil flow and potential stagnation, which complicates cooling performance and increases costs with additional pumps or valves.
Innovation Solution
A rotary electric machine apparatus with a communication pipe that balances internal pressures between the motor and generator housings, using a single pump to supply cooling liquid in parallel and returning it through a shared liquid reservoir, preventing pressure differences and ensuring stable cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump supplies cooling liquid to both motor and generator, then device complexity is reduced, but pressure difference between housings causes uneven cooling liquid flow and stagnation
Solution Approach 1:
The cooling system is segmented into two independent cooling circuits - one for the motor and one for the generator - each with its own pump. This allows independent pressure control for each rotary electric machine, ensuring reliable cooling liquid flow to both units without the pressure difference problems that would occur with a single shared pump.
2Reliability
If additional pumps or valve devices are provided to regulate cooling liquid flow, then cooling liquid flow stability is improved, but device complexity and cost increase
Solution Approach 1:
Instead of adding complex valve devices to a single-pump system, the solution segments the system into two independent cooling circuits, each with its own pump. This achieves reliable flow control through system architecture rather than additional regulating components.
3Device complexity
If cooling oil is supplied into both housings through a single pump, then device complexity is reduced, but uneven cooling performance occurs due to pressure differences
Solution Approach 1:
The cooling system is divided into separate circuits for the motor and generator, each with dedicated pumping capability. This ensures that each rotary electric machine receives adequate cooling liquid flow regardless of pressure differences in the other unit, maintaining uniform cooling performance across both devices.
4Reliability
If a communication pipe balances internal pressures between housings, then pressure difference is eliminated, but device complexity increases
Solution Approach 1:
The two cooling circuits are merged through a communication pipe that connects the interior spaces of the motor housing and generator housing. This allows pressure equalization between the two units, eliminating the pressure difference problem while maintaining the benefit of having two pumps for independent flow control.
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 eliminates pressure differences, stabilizes cooling liquid flow, prevents stagnation, and maintains cooling performance without the need for complex mechanisms or additional pumps, ensuring efficient and balanced cooling for both motor and generator.
Implementation Method 1
a communication pipe that communicates a gas-phase in the first housing and a gas-phase in the second housing so that an internal pressures of the first housing and the second housing are balanced to each other
Data Source
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AI summary
A rotary electric machine apparatus includes a first rotary electric machine that includes a first rotor, a first stator and a first housing for containing the first rotor and the first stator, a second rotary electric machine that includes a second rotor, a second stator and a second housing for containing the second rotor and the second stator, a pump that supplies a cooling liquid to the first rotary electric machine and the second rotary electric machine, and a communication pipe that communicates a gas-phase in the first housing and a gas-phase in the second housing so that an internal pressures of the first housing and the second housing are balanced to each other.