Planetary EV Drive Layout for Compact Torque Vectoring
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Solution Overview
Problem
Existing electric vehicle drive apparatuses require additional planetary gears to implement a torque vectoring function, leading to increased full length and manufacturing costs, as well as difficulties in incorporating the torque vectoring structure.
Innovation Solution
The electric vehicle drive apparatus combines planetary gears to enable both speed reduction and torque vectoring functions, utilizing a third planetary gear set connected to a torque vectoring motor, which allows for the realization of torque vectoring with only one set of additional planetary gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two sets of planetary gears are added to implement torque vectoring function, then torque vectoring capability is improved, but full length increases and device complexity increases
Solution Approach 1:
The patent merges the speed reduction function and torque vectoring function into a single integrated planetary gear system. The first planetary gear set performs speed reduction while the second planetary gear set performs torque vectoring, with both functions sharing common components (sun gear, carrier, ring gear). This integration eliminates the need for separate differential mechanisms and reduces the overall full length compared to using two independent planetary gear sets.
Solution Approach 2:
The planetary gear system is designed to perform multiple functions simultaneously. The first planetary gear set provides speed reduction for the output shaft, while the second planetary gear set provides torque vectoring capability for the drive wheels. The same basic planetary gear structure (sun gear, planetary gears, carrier, ring gear) is used for both functions, making the system universal and multi-functional.
2Adaptability or versatility
If two sets of planetary gears are added to implement torque vectoring function, then torque vectoring capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines speed reduction and torque vectoring functions into one integrated planetary gear assembly, reducing the total number of components that need to be manufactured and assembled. By sharing common elements (sun gear, carrier, ring gear) between the two functions, the manufacturing complexity and cost are reduced compared to implementing torque vectoring with completely separate planetary gear sets.
Solution Approach 2:
The planetary gear sets are designed with universal components that serve dual purposes. The first planetary gear set's output serves as input to the second set, creating a cascaded system where components are reused. This multi-functionality reduces the total component count and manufacturing cost while maintaining both speed reduction and torque vectoring capabilities.
3Device complexity
If separate differential is not mounted, then device complexity is reduced, but torque vectoring function cannot be incorporated
Solution Approach 1:
The patent merges the differential function and torque vectoring function into the planetary gear system itself. The second planetary gear set acts as an integrated differential mechanism that distributes torque to the drive wheels while providing active torque vectoring control. This eliminates the need for a separate differential housing and components, reducing device complexity while maintaining torque vectoring capability.
Solution Approach 2:
The planetary gear system is designed to perform multiple functions: speed reduction (first planetary set), differential torque distribution (second planetary set), and active torque vectoring (through control of the second planetary set). This multi-functionality allows the system to replace what would traditionally require separate differential and torque vectoring components, reducing overall device complexity.
Data Source
AI summary
An embodiment electric vehicle drive apparatus for decreasing a drive speed of a motor and transferring the decreased drive speed to an output shaft is provided. The apparatus includes a first planetary gear set including three first planetary gear elements in which a first element is connected to the motor and a second element is connected to a first output shaft, a second planetary gear set including three second planetary gear elements in which a first element is connected to a third element of the three first planetary gear elements, a second element is connected to a second output shaft, and a third element is fixed, and a third planetary gear set including three third planetary gear elements in which first and second elements are connected to two elements of the three first planetary gear elements, respectively, and a third element is connected to a torque vectoring motor.