Torque Vectoring Apparatus Using Compound Planetary Gears
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Solution Overview
Problem
Existing torque vectoring systems in vehicles face challenges in achieving optimal torque control and minimizing power loss, especially in high-performance electric vehicles, where precise control of torque distribution between wheels is necessary for improved agility and stability.
Innovation Solution
A torque vectoring apparatus comprising a speed reduction device, a differential device, and a torque vectoring device with a torque vectoring control motor and compound planetary gear sets, which allows for adjustable torque ratio distribution between left-side and right-side output shafts, minimizing power loss and enhancing controllability by disconnecting torque transmission when excessive vehicle speed is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional differential device is used to distribute torque to left-side and right-side drive wheels, then the basic torque distribution function is achieved, but the torque vectoring function for active control of torque distribution ratio cannot be realized
Solution Approach 1:
The patent merges the differential device and torque vectoring device into a single integrated unit. The torque vectoring device includes planetary gear sets that share common components with the differential device, such as the sun gear, planet gears, and ring gear. This integration allows active torque distribution control between left-side and right-side drive wheels while avoiding the need for separate independent systems, thus achieving enhanced adaptability without proportionally increasing device complexity.
Solution Approach 2:
The differential device is designed to perform multiple functions: it provides both the basic torque distribution function and the active torque vectoring function. By incorporating torque vectoring control capabilities directly into the differential device structure, the system achieves universal functionality that covers both passive differential operation and active torque vectoring control, eliminating the need for separate dedicated systems.
2Reliability
If torque vectoring control is added to improve vehicle dynamics and cornering performance, then agility and handling performance are enhanced, but power loss increases
Solution Approach 1:
The torque vectoring control motor is designed to operate dynamically, adjusting its output torque based on real-time driving conditions and vehicle state. The control system monitors parameters such as steering angle, vehicle speed, and wheel slip to determine the optimal torque distribution ratio, enabling the system to provide active torque vectoring only when necessary for improving stability or cornering performance, rather than continuously operating at full capacity.
Solution Approach 2:
The system changes operational parameters of the torque vectoring control motor based on driving conditions. The motor's output torque and rotation speed are adjusted according to the required torque distribution ratio, which varies with vehicle speed, steering angle, and road conditions. This parameter adaptation allows the system to achieve improved vehicle dynamics while minimizing energy consumption by operating the motor only at necessary levels.
3Measurement precision
If a torque vectoring control motor is introduced to adjust torque distribution ratio, then precise torque control is achieved, but the overall system complexity increases
Solution Approach 1:
The torque vectoring control motor and planetary gear sets are nested within the existing differential device structure. The control motor is positioned to directly drive the planetary gear mechanism, which is itself integrated with the differential's sun gear, planet gears, and ring gear. This nested arrangement allows precise torque control functionality to be embedded within the compact differential housing, minimizing space requirements and reducing overall system complexity despite the addition of control capabilities.
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
The apparatus achieves improved cornering performance and stability in electric vehicles by optimizing torque distribution and minimizing power loss, applicable to various electric vehicle types, including hybrid and plug-in hybrid models, thereby enhancing fuel efficiency.
Implementation Method 1
a first compound planetary gear set including first and second planetary gear sets, and a second compound planetary gear set including third and fourth planetary gear sets
Data Source
AI summary
A drive torque received from a power source is split and output to first and second output shafts through a torque vectoring apparatus including a torque vectoring device that controls a torque ratio of split torques, where the torque vectoring device includes a control motor, a first compound planetary gear set including first and second planetary gear sets having a first rotation element fixed to a housing, a shared second rotation element connected to the first output shaft, and a third rotation element, and a second compound planetary gear set including third and fourth planetary gear sets having a shared fourth rotation element connected to the second output shaft, a fifth rotation element connected to a third rotation element, and a sixth rotation element connected to the control motor.