Power-Split Vehicle Transmission for Compact Multi-Gear Torque Paths
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Solution Overview
Problem
Current transmissions for heavy-duty electric vehicles face challenges in balancing packaging and performance while being cost-effective, and they often lack commonality across different power levels and installations.
Innovation Solution
A transmission design featuring a planetary gearset with a power split configuration, including a sun gearwheel, planet gearwheels, and gearwheels connected via gear engaging devices to provide multiple selectable gear connections, allowing for torque split and reduced load-independent losses, resulting in a compact and cost-effective configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional transmission designs are used for electric vehicles, then packaging requirements may be met, but performance and cost-effectiveness deteriorate
Solution Approach 1:
The transmission is divided into modular components including a planetary gearset module and a geartrain module with selectable gear connections. This segmentation allows independent optimization of each module for both compact packaging and high performance, while enabling cost-effective manufacturing through standardized modules that can be adapted to different power levels.
Solution Approach 2:
The transmission design uses universal modules such as the planetary gearset and gearwheels that can serve multiple functions across different vehicle applications and power levels. The same basic modules can be configured to provide different gear ratios and torque splits, achieving high commonality and cost-effectiveness while meeting diverse performance requirements.
2Adaptability or versatility
If transmissions are adapted for traditional powertrains, then existing designs can be used, but adaptability to electric powertrains deteriorates
Solution Approach 1:
The transmission incorporates selectable gear connections that can be dynamically configured through gear engaging devices. This allows the transmission to adapt its gear ratios and torque split characteristics based on the specific electric powertrain application, achieving high adaptability across different power levels while using a standardized modular architecture that reduces overall complexity.
3Loss of energy
If a single torque path is used, then device complexity is reduced, but energy losses increase
Solution Approach 1:
The planetary gearset acts as an intermediary that enables torque splitting into multiple parallel torque paths. One path goes through the gearwheels and another through the planetary gearset, allowing torque to be distributed in a way that reduces load-independent losses. The gear engaging devices control which torque paths are active, managing the complexity while achieving energy efficiency.
Data Source
AI summary
A transmission for a vehicle includes an input shaft, a planetary gearset comprising a sun gearwheel, one or more planet gearwheels, a planet gearwheel holder and a planet ring gearwheel, a first gearwheel, a second gearwheel, a third gearwheel, a fourth gearwheel and a fifth gearwheel, an output shaft, and at least two gear engaging devices which are configured to provide at least four selectable gear connections. The planet ring gearwheel is rotatably connected or connectable to the first gearwheel. A first gear engaging device is configured to be provided in a first state where it rotationally connects the second gearwheel to the fourth gearwheel and in a second state where it rotationally disconnects the second gearwheel from the fourth gearwheel. The third selectable gear connection is provided by at least setting the first gear engaging device in the first gear engaging device first state.