Three-Speed EV Transmission Layout for Flexible Drop Packaging
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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 due to high input speeds from electric motors.
Innovation Solution
A three-speed electric transmission system with a flexible output shaft configuration that can be arranged in either a short drop or long drop configuration, allowing for adaptability to different vehicle applications and reducing stress on transmission components through speed reduction.
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 can achieve multiple gear ratios, but the width of the transmission increases which poses barriers to integration in certain vehicle platforms
Solution Approach 1:
The patent positions clutches on different shafts (input shaft and intermediate shaft) rather than concentrating them on the output shaft. This spatial redistribution across multiple dimensions allows multiple gear ratios to be achieved without increasing the transmission width, as the clutch engagement control is distributed across different axial positions and shafts.
Solution Approach 2:
The transmission system is segmented into multiple shafts (input shaft, intermediate shaft, output shaft) with clutches distributed across these shafts. Each clutch controls specific gear engagements on its designated shaft, dividing the gear ratio control function across multiple segments rather than concentrating all control mechanisms on a single output shaft.
2Ease of manufacture
If the transmission is designed with a fixed drop configuration to meet specific vehicle packaging demands, then it can be optimized for that specific application, but it becomes incompatible with other vehicle types that demand different drop lengths
Solution Approach 1:
The transmission system incorporates an adjustable intermediate shaft that can be positioned at different locations along the transmission housing. This dynamic repositioning capability allows the drop length to be adjusted to meet different vehicle packaging requirements while maintaining the same transmission design, enabling compatibility across multiple vehicle types without requiring separate transmission designs.
Solution Approach 2:
The transmission design achieves universality by incorporating the adjustable intermediate shaft mechanism that can accommodate multiple drop configurations. This single transmission design can serve multiple vehicle applications (both long drop and short drop configurations) by adjusting the intermediate shaft position, eliminating the need for separate specialized transmissions for different vehicle types.
3Use of energy by moving object
If high input speeds are transmitted directly to the output shaft to maintain efficiency, then power transmission efficiency is improved, but degradation occurs to internal components such as clutches and gears
Solution Approach 1:
The transmission system performs preliminary speed reduction through the gear train before power is transmitted to the output shaft. By reducing the speed of rotating components (gears and clutches) before they engage in power transmission, the system protects these internal components from high-speed degradation while maintaining efficient power delivery to the output.
Solution Approach 2:
The intermediate shaft acts as a mediator between the high-speed input shaft and the output shaft. It receives high-speed input, undergoes gear reduction through intermediate gears, and then transmits the reduced-speed power to the output shaft. This intermediary mechanism protects the clutches and gears from direct exposure to high input speeds while maintaining power transmission efficiency.
Data Source
AI summary
Systems and method are herein provided for a three-speed electric transmission system. In one example, a transmission system includes 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 a second clutch shaft; a third clutch positioned on the first clutch shaft; an idler shaft; and an output shaft rotationally coupled to the idler shaft, wherein the output shaft is in one of a first position and a second position.