Three-Speed EV Transmission Layout for Packaging and Speed Reduction
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Solution Overview
Problem
Existing electric vehicle transmission systems face challenges such as increased width due to multiple gears or clutches on the output shaft, incompatibility with varying vehicle packaging demands, and degradation of components from high input speeds.
Innovation Solution
A three-speed electric transmission system with a flexible output shaft configuration, allowing for either a short drop or long drop arrangement, and incorporating an input speed reduction gear set to mitigate component degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple gears or clutches are positioned on the output shaft to provide multiple speeds, then the transmission provides greater versatility and adaptability, but the width of the transmission increases which poses barriers to integration in certain vehicle platforms
Solution Approach 1:
The patent redistributes clutches from a single output shaft to multiple shafts (input shaft, intermediate shaft, and output shaft), effectively moving the clutch arrangement from a one-dimensional concentration to a two-dimensional distributed layout. This dimensional change allows the transmission to achieve multiple speeds without increasing width, as the clutches are spread across different shafts rather than stacked on one shaft.
Solution Approach 2:
The transmission system is segmented into multiple shafts (input shaft, intermediate shaft, and output shaft), with clutches distributed across these separate segments. This segmentation allows each shaft to have fewer clutches, reducing the width requirement on any single shaft while maintaining the overall multi-speed capability through the distributed clutch arrangement.
2Speed
If high input speeds are transmitted directly to the output shaft, then the transmission responds quickly, but degradation occurs to internal components such as clutches and gears
Solution Approach 1:
An intermediate shaft is introduced as a mediator between the input shaft and output shaft. This intermediate shaft, along with the distributed clutch arrangement, allows for speed modulation and load distribution that reduces the direct transmission of high input speeds to all components, thereby reducing degradation while maintaining responsive performance.
3Device complexity
If the transmission is designed with a fixed drop configuration, then the design is simplified, but it becomes incompatible with certain vehicle applications that demand different drop lengths
Solution Approach 1:
The transmission design incorporates dynamic configurability through the selective engagement of clutches distributed across multiple shafts. This allows the transmission to adapt its effective drop configuration based on operational requirements, providing compatibility with different vehicle applications (such as loaders requiring long drops versus on-highway vehicles requiring short drops) without increasing design complexity, as the same physical structure can dynamically assume different functional configurations.
Data Source
AI summary
Systems and methods are herein provided for a three-speed electric transmission system. In one example, a transmission system comprises a first electric motor coupled to an input speed reduction gear train, wherein the input speed reduction gear train rotationally couples to an input shaft; a second electric motor coupled to the input speed reduction gear train; a first clutch positioned on a first clutch shaft; a second clutch positioned on the input shaft; a third clutch positioned on a second clutch shaft; and an output shaft rotationally coupled to the second clutch shaft, wherein the output shaft is in one of a first position and a second position.