Coaxial Electric Machine Integration in Hybrid Drive Trains
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive train systems for all-wheel drive motor vehicles face challenges in optimizing installation space and weight distribution, particularly in hybrid configurations where both mechanical and electric power sources are integrated, leading to inefficiencies in power transmission and component alignment.
Innovation Solution
A drive train design where an electric machine is coaxially arranged with the input shaft of a transverse differential on the second axle, integrated with a planetary gear set and a shifting clutch, allowing for efficient power transmission and flexible operation modes, including the use of a cardan shaft to connect both axles and enable power distribution from the drive unit to the second axle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the electric machine is arranged in the area of the second axle with coaxial alignment to the input shaft of the transverse differential, then weight distribution and space utilization are improved, but the complexity of integrating the electric machine with existing drive train components increases
Solution Approach 1:
The electric machine is merged with the transverse differential by arranging the electric machine's drive shaft coaxially with the input shaft of the transverse differential, creating an integrated assembly where both components share common mounting structures and power flow paths, thereby improving weight distribution without proportionally increasing integration complexity
Solution Approach 2:
The input shaft of the transverse differential serves dual functions: it receives power from the cardan shaft connecting to the first axle and simultaneously serves as the drive shaft for the electric machine, allowing a single component to fulfill multiple roles in the hybrid drive train system
2Volume of moving object
If a planetary gear set is arranged coaxially to the electric machine, then the construction becomes more compact, but the structural complexity of the coaxial arrangement increases
Solution Approach 1:
The planetary gear set is nested within the coaxial structure of the electric machine, with the sun gear, planet gears, and ring gear arranged concentrically around the electric machine's drive shaft, allowing the reduction stage to be contained within the same radial envelope as the electric machine itself, thereby achieving compact construction
Solution Approach 2:
The planetary gear set utilizes the radial dimension around the coaxial drive shaft to arrange its components, transforming the linear power flow into a radial configuration that achieves compact volumetric arrangement while maintaining the same power transmission function
3Adaptability or versatility
If the cardan shaft is used to connect the first and second axles, then power transmission flexibility is improved, but the loss of power during transmission increases
Solution Approach 1:
The cardan shaft acts as an intermediary power transmission element between the first axle and the second axle, allowing flexible angular connections and accommodating misalignments while transmitting power, though inherent in the use of this mechanical intermediary is some power loss due to friction and inefficiencies in the cardan joint mechanism
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a drive train (20) for a motor vehicle (10) which has a first and a second axle (12, 14), wherein a drive unit (22) is arranged in the region of the first axle (12), wherein the drive train (20) furthermore has an electric machine (40) which can be connected to the second axle (14), and wherein the electric machine (40) is arranged in the longitudinal direction (42) coaxially with respect to an input shaft of a transverse differential (30) of the second axle (14).