Axle Assembly Torque Vectoring via Planetary Gear Reaction Mass
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque-vectoring differentials (TVDs) in vehicles are susceptible to improvements in terms of efficiency and effectiveness in reducing understeer or oversteer by redistributing torque between wheels, as they often rely on complex mechanisms like gear reductions and magnetic particle brakes which can be cumbersome and inefficient.
Innovation Solution
The axle assembly incorporates a dual planetary gear set with a drive member that applies equal but oppositely directed torque to the wheels through a differential assembly, allowing for compact and lightweight torque distribution, and includes a shiftable element to switch between torque vectoring and drive modes, enhancing turning behavior and reducing turning radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex mechanisms like gear reductions and magnetic particle brakes are used in TVD, then torque vectoring function is achieved, but device complexity and inefficiency increase
Solution Approach 1:
The patent merges the torque vectoring function directly into the differential mechanism by using a reaction mass mounted on bearings within the differential case. This integration eliminates the need for separate gear reductions and magnetic particle brakes, achieving torque vectoring through the interaction between the reaction mass and differential components, thereby reducing device complexity while maintaining the torque vectoring function.
Solution Approach 2:
The patent replaces complex mechanical systems (gear reductions and magnetic particle brakes) with a simpler mechanical approach using a reaction mass that utilizes centrifugal force and inertial effects. The reaction mass rotates with the differential case and generates torque vectoring through its offset center of gravity, substituting cumbersome mechanical components with a more efficient inertial mechanism.
2Adaptability or versatility
If torque is redistributed between wheels using conventional TVD mechanisms, then understeer or oversteer is corrected, but energy losses increase
Solution Approach 1:
The reaction mass automatically generates torque vectoring based on the differential case rotation and vehicle dynamics without requiring external energy input or control systems. The offset center of gravity of the reaction mass creates inertial forces that naturally redistribute torque between wheels during cornering, allowing the system to self-regulate torque distribution based on operating conditions, thereby minimizing energy losses.
3Volume of moving object
If compact and lightweight torque distribution is achieved using dual planetary gear sets, then device size is reduced, but manufacturing complexity increases
Solution Approach 1:
The differential case serves multiple functions: it houses the traditional differential mechanism for torque splitting, mounts the reaction mass for torque vectoring, and provides the rotating reference frame for the planetary gear sets. This multi-functionality reduces the overall number of components and assembly steps, making the compact design more manufacturable despite the sophisticated torque distribution 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
This configuration effectively improves vehicle turning behavior by distributing torque between wheels, reducing the turning radius, and minimizing losses during straight driving by ensuring equal torque distribution when not actively vectoring torque, resulting in improved handling and efficiency.
Implementation Method 1
a first planetary gear set having a first transmission input that is driven by the input member; a differential assembly having a differential carrier and first and second differential output members received in the differential carrier; a second planetary gear set having a planet carrier coupled to the differential carrier for common rotation
Data Source
AI summary
An axle assembly with a differential assembly, a housing and a transmission. The transmission has a first and second planetary gearsets that have associated (i.e., first and second) ring gears, planet carriers and sun gears. The first planet carrier is coupled to a differential carrier of the differential assembly for common rotation. The second ring gear is non-rotatably coupled to the housing. The second planet carrier is coupled to the second differential output for common rotation. The second sun gear is coupled to the first sun gear for common rotation.