Rotary Electric Machine Unit Internal Cooling Passage
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Solution Overview
Problem
Conventional rotary electric machine units face inefficiencies in cooling, particularly as heat accumulates near the top portion, leading to reduced cooling effectiveness within the housing due to the external cooling configuration.
Innovation Solution
The rotary electric machine unit incorporates a power converter with a device cooling passage that has a coolant inlet higher than the outlet, allowing coolant with high cooling capacity to flow downward and cool the internal space effectively, thereby preventing temperature rise and enhancing the cooling effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cooling device is provided outside the rotary electric machine to cool both the rotary electric machine and power converter, then the cooling system can be simplified, but the cooling effectiveness inside the power converter housing is reduced due to heat accumulation near the top portion
Solution Approach 1:
The cooling device is nested within the power converter housing, with the cooling passage integrated into the housing structure. The housing itself forms part of the cooling system, with cooling passages embedded in the housing walls that allow coolant to flow through and cool the internal components directly at the heat source locations.
Solution Approach 2:
The cooling approach transitions from external cooling to internal cooling by adding cooling passages within the housing structure. This dimensional change allows coolant to reach components from multiple directions including top-down cooling, addressing the heat accumulation problem at the top portion of the housing.
2Device complexity
If the power converter is provided outside the rotary electric machine, then the rotary electric machine structure is simplified, but the cooling effectiveness for the power converter is reduced
Solution Approach 1:
The cooling device is merged with the power converter housing to form an integrated cooling system. The housing serves dual functions as both the structural enclosure and the cooling system component, with cooling passages integrated into the housing walls to cool the power converter components.
Solution Approach 2:
The housing acts as an intermediary between the coolant and the power converter components. The cooling passages within the housing walls serve as heat transfer pathways, allowing efficient thermal coupling between the coolant and the power converter components while maintaining the external placement configuration.
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 enhances the cooling efficiency by ensuring that the coolant with high cooling capacity cools the internal space, reducing the risk of temperature increase and improving the overall cooling performance of the power converter.
Implementation Method 1
a cooling device is provided to a power converter and a rotary electric machine to cool the power converter and the rotary electric machine with coolant flowing inside the cooling device
Implementation Method 2
a device cooling passage that has a coolant inlet higher than the outlet
Data Source
AI summary
In a motor unit, a power converter is provided to an outer circumferential surface of a motor case at a position distant from an outer top portion in a circumferential direction. In a power converter, a power module and a control board are accommodated in an internal space of a device case. A power converter is provided with a device cooler. A device cooler has a device cooling passage extending along a power module. In the device cooling passage, a device inlet, into which coolant flows, and a device outlet, from which coolant flows out, are provided side by side in a circumferential direction. The device inlet is located a position higher than the device outlet in the Y direction.