Compact Unit Integrating Inverter and Gears via Axial Overlap
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Solution Overview
Problem
Existing vehicle drive devices with separate rotating electrical machines and power transmission mechanisms face inefficiencies in layout, leading to larger overall sizes due to separate components.
Innovation Solution
A unit is designed with a rotating electrical machine, inverter, and gear mechanisms arranged to overlap and separate components, reducing interference and axial dimensions, and incorporating a differential gear mechanism to enhance compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the rotating electrical machine and power transmission mechanism are provided separately, then each component can be independently designed and manufactured, but the overall size becomes larger and layout efficiency deteriorates
Solution Approach 1:
The patent combines the rotating electrical machine and power transmission mechanism into a single integrated unit. The stator of the rotating electrical machine is positioned to overlap with the third gear in the axial direction, while the inverter overlaps with the second gear, creating a compact integrated structure that reduces overall volume while maintaining independent manufacturability of sub-components
2Productivity
If multiple gears are arranged in sequence, then power transmission function is achieved, but interference between gears occurs and axial dimension increases
Solution Approach 1:
The patent transitions from a linear sequential arrangement of gears to a multi-dimensional overlapping layout. The second gear and third gear are arranged to overlap in the axial direction, with the shaft passing through the outer periphery of the rotating electrical machine body, allowing power transmission while reducing axial dimension and avoiding gear interference
3Reliability
If the inverter is positioned away from the gears, then electrical isolation is maintained, but available space for inverter installation is insufficient
Solution Approach 1:
The patent employs a nested overlapping arrangement where the inverter is positioned to overlap with the second gear in the axial direction, and the second gear overlaps with the third gear. This nested configuration maximizes space utilization while maintaining electrical isolation through the gear structure, providing sufficient installation space for the inverter
Data Source
AI summary
A unit includes: a rotating electrical machine; an inverter located in an outer periphery of the rotating electrical machine; a first gear connected downstream of the rotating electrical machine; a second gear to mesh with the first gear; a third gear connected downstream of the second gear via a shaft; and a fourth gear to mesh with the third gear. The shaft has a portion that overlaps a stator of the rotating electrical machine when viewed in a radial direction, and the inverter has a portion that overlaps the second gear when viewed in an axial direction.