Drive Unit Heat Management via Shaft Mediator
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Solution Overview
Problem
In vehicles with rotary electric machines and electric power conversion devices, the close proximity leads to heat transfer from the rotary electric machine to the electric power conversion device, causing potential temperature-related output restrictions.
Innovation Solution
A drive unit design where the electric power conversion device is arranged on one side of the rotary electric machine, with an output shaft positioned between them, creating a space that prevents heat transfer and allows for efficient cooling through a refrigerant-cooled cooling part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the electric power conversion device is arranged close to the rotary electric machine to reduce overall size, then the device complexity and volume are reduced, but heat from the rotary electric machine is transmitted to the electric power conversion device causing temperature-related output restrictions
Solution Approach 1:
The output shaft is positioned as an intermediary component between the rotary electric machine and the electric power conversion device. This spatial arrangement uses the output shaft as a physical barrier that interrupts direct heat transfer pathways, allowing the electric power conversion device to be located close to the rotary electric machine while preventing excessive heat transmission that would cause temperature-related output restrictions.
2Length of stationary object
If the electric power conversion device is arranged close to the rotary electric machine, then the drive unit height dimension is reduced, but heat transfer causes output restrictions
Solution Approach 1:
The output shaft serves as a mediator that enables close proximity arrangement of the electric power conversion device and rotary electric machine without direct thermal coupling. This allows the drive unit height to be minimized while the output shaft physically separates the heat source from the sensitive electronic components, preventing output restrictions.
Solution Approach 2:
The patent arranges components in a compact configuration where the output shaft extends in a direction that optimizes spatial utilization. By positioning the electric power conversion device on one side of the rotary electric machine with the output shaft between them, the design achieves reduced height dimension while maintaining thermal separation through three-dimensional spatial arrangement.
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 effectively suppresses heat transfer from the rotary electric machine to the electric power conversion device, reducing temperature-related output restrictions and allowing for a compact, high-performance drive unit with reduced height dimensions.
Implementation Method 1
a cooling part provided between the board and the output shaft, and through which the refrigerant flows
Data Source
AI summary
A drive unit includes: a rotary electric machine; a rotary electric machine case accommodating the rotary electric machine; an electric power conversion device electrically connected to the rotary electric machine and configured to convert electric power supplied to the rotary electric machine and electric power supplied from the rotary electric machine; and an output shaft extending out from the rotary electric machine case and configured to output power of the rotary electric machine. The electric power conversion device is arranged on one side of the rotary electric machine. The output shaft is arranged between the rotary electric machine and the electric power conversion device.