Integrated Planetary Gear Drive for EV Torque Vectoring
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Solution Overview
Problem
Current electric vehicle drive systems face challenges in achieving compact arrangement and improved efficiency due to packaging requirements and mechanical losses associated with traditional motor drive systems.
Innovation Solution
The electric vehicle drive system incorporates a differential planetary gear set and a reversal planetary gear set with optional clutches and a torque transfer device to provide a compact, efficient, and adaptable power transmission system, enabling speed reduction and torque vectoring for enhanced vehicle handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional electric motor drive systems are used, then the system is simple to implement, but the packaging requirements increase and efficiency decreases
Solution Approach 1:
The patent combines differential gearing and reduction gearing into a single integrated planetary gear set. The first planetary gear set simultaneously performs both differential function (splitting torque between left and right wheels) and reduction function (reducing motor speed while increasing torque). This merging eliminates the need for separate gearing components, reducing overall system complexity while improving efficiency by minimizing mechanical losses through fewer engagement points.
2Length of moving object
If traditional electric motor drive systems are used, then the system structure is simple, but the cross-vehicle axial distance increases
Solution Approach 1:
The patent employs a nested planetary gear configuration where the second planetary gear set is positioned within or adjacent to the first planetary gear set. The second sun gear is rotatably connected to the first ring gear, creating a compact nested arrangement. This nesting allows both differential and reduction functions to be accomplished within a minimized axial footprint, directly reducing the cross-vehicle axial distance while managing gearing complexity through systematic spatial organization.
3Adaptability or versatility
If fixed torque distribution is used, then the system is simple to control, but vehicle handling during turns deteriorates
Solution Approach 1:
The patent incorporates controllable clutches (first optional clutch connecting planet carriers, second and third optional clutches on axle shafts) that can dynamically adjust torque distribution between left and right wheels based on real-time driving conditions. During turns, these clutches enable differential torque vectoring to improve handling. The torque transfer device also provides dynamic torque redistribution capability. This dynamic control system adapts to varying operational requirements while the modular clutch architecture manages complexity through standardized controllable components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces spin losses, minimizes cross-vehicle axial distance, and allows for improved torque distribution to wheels during turns, enhancing vehicle handling and efficiency compared to traditional systems.
Implementation Method 1
A plurality of first planet gears are supported by a first planet carrier and in meshing engagement with the first sun gear and a first ring gear
Data Source
AI summary
An electric vehicle drive system includes an electric motor, first and second planetary gear sets, including sun gear, carrier and ring gear members, first and second output shafts, and a housing. The members of the first planetary gear set are connected with the electric motor, the first output shaft, and a member of the second planetary gear set. The members of the second planetary gear set are connected with the first planetary gear set, the housing, and the second output shaft. The first planetary gear set provides differential reduction and the second planetary gear set provides reversal and reduction. Optional clutches can provide the function of a limited slip differential and distribute torque preferentially to one output shaft or the other.