Multi-Speed Electric Drive Unit Layout for Compact AWD Packaging
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Solution Overview
Problem
Existing dual-motor electric drive units face integration challenges due to increased width and incompatible packaging demands in certain vehicle platforms, particularly in all-wheel drive loaders, as a result of synchronizer placement and planetary gear assemblies.
Innovation Solution
A multi-speed transmission system with coaxially arranged electric machines, friction clutches, and countershafts that allow for compact packaging and efficient gear shifting, reducing power interruptions during shifting transients, and incorporating a scavenger pump to enhance lubrication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synchronizer is positioned on the input shaft to achieve optimal synchronization efficiency, then synchronization performance is improved, but the transmission width increases which creates packaging barriers
Solution Approach 1:
The patent repositions the synchronizer from the input shaft to the output shaft, changing the spatial arrangement dimension. This dimensional change allows the synchronizer to be located where it does not interfere with the width constraints of the transmission housing, thereby maintaining synchronization efficiency while reducing overall transmission width for better packaging.
Solution Approach 2:
Instead of placing the synchronizer on the input shaft as in conventional designs, the patent inverts the approach by positioning it on the output shaft. This inversion resolves the conflict between synchronization performance and width constraints by locating the synchronizer in a different spatial position where it does not increase transmission width.
2Volume of moving object
If planetary gear sets are used to achieve gear reduction, then compactness is improved, but the drop and width become incompatible with certain vehicle platforms
Solution Approach 1:
The patent divides the transmission into multiple shafts (input shaft, intermediate shaft, output shaft) with distributed gear arrangements. This segmentation allows the transmission to achieve the required gear reduction ratios while controlling the overall drop dimension, making it compatible with vehicle platforms that have specific packaging requirements.
Solution Approach 2:
The patent adopts a multi-shaft configuration that distributes components across different axial positions, changing the dimensional layout from a single-stage planetary arrangement. This dimensional redistribution achieves gear reduction while controlling the drop dimension to meet vehicle integration requirements.
3Adaptability or versatility
If multiple gears are positioned on downstream shafts to achieve gear reduction, then gear ratio adaptability is improved, but the transmission width increases which does not meet packaging demands
Solution Approach 1:
The patent arranges multiple gears on intermediate and output shafts in a distributed configuration that optimizes the width dimension. By carefully selecting gear positions and ratios on these shafts, the system achieves multiple gear ratios while keeping the overall transmission width within packaging constraints.
Solution Approach 2:
The patent applies different gear arrangements to different shafts, with each shaft having gears positioned at specific locations optimized for its function. This local optimization allows the transmission to achieve multiple gear ratios without uniformly increasing the width across all components.
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
The system achieves desired width and drop for efficient integration into various vehicle platforms while minimizing power interruptions during gear shifts, enhancing transmission performance and customer appeal.
Implementation Method 1
a first friction clutch arranged coaxial to a first countershaft... a second friction clutch arranged coaxial to a second countershaft
Data Source
AI summary
Systems and methods for an electric drive unit are provided. A transmission system in an electric drive unit, in one example includes an input shaft rotationally coupled to each of a first electric machine and a second electric machine and a first clutch arranged coaxial to a first countershaft, where a first gear is fixedly coupled the first clutch and meshes with a second gear that is fixedly coupled to the input shaft. The transmission system further includes a second clutch arranged coaxial to a second countershaft and spaced away from the first countershaft and a third gear that is fixedly coupled to the second clutch and meshes with the first gear, where the first clutch and the second clutch are configured to shift the transmission system between multiple gear ratios and deliver mechanical power to an output shaft that is spaced away from the second countershaft.