Planetary Transmission Torque Transfer for Wheel Traction Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle transmissions with integrated differentials lack a locking torque mechanism, which impairs traction and vehicle handling, especially when one wheel loses contact with the ground, leading to reduced propulsion capabilities.
Innovation Solution
A transmission design featuring a shifting element that connects output shafts for torque transfer without requiring conjoint rotation, allowing torque to be redirected radially through a sliding or slipping mechanism, and incorporating a nested planetary gearset configuration for compactness and efficient torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional open differential is used, then the transmission structure is simple, but torque cannot be transferred to the wheel with traction when one wheel loses contact with the ground
Solution Approach 1:
The patent implements a nested planetary gearset configuration where a first planetary gearset and a second planetary gearset are arranged concentrically around a common input shaft. The first planetary gearset includes sun gear, planet gears, and ring gear, while the second planetary gearset is positioned within the same radial space. This nesting approach enables torque transfer to the wheel with traction while maintaining a compact and relatively simple transmission structure, resolving the contradiction between reliability improvement and device complexity.
2Reliability
If a differential lock mechanism is added to prevent torque loss, then traction capability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a shifting element that automatically engages and disengages based on the torque distribution between the two output shafts. When one wheel loses traction, the torque imbalance automatically causes the shifting element to redirect torque to the wheel with traction without requiring external actuation or complex control systems. This self-service mechanism improves traction capability while avoiding the manufacturing complexity associated with actuated differential locks.
3Reliability
If multiple planetary gearsets are added to enable torque transfer, then traction and handling are improved, but the transmission size and complexity increase
Solution Approach 1:
The patent positions the first and second planetary gearsets in a nested arrangement where both gearsets share a common input shaft and are arranged concentrically. The first planetary gearset handles primary torque conversion, while the second planetary gearset manages torque distribution to the output shafts. This nested configuration enables sophisticated torque transfer capabilities for improved vehicle handling while minimizing the overall transmission size and structural complexity.
Solution Approach 2:
The patent combines the functions of torque conversion and torque distribution into a single integrated transmission unit. The first planetary gearset performs torque conversion from the input shaft, while the second planetary gearset simultaneously performs torque distribution to the two output shafts. By merging these functions into one compact assembly rather than using separate mechanisms, the patent achieves improved vehicle handling without proportionally increasing device complexity.
4Productivity
If a shifting element with radial torque transfer is implemented, then torque distribution efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent introduces a shifting element as an intermediary component that mediates torque transfer between the two output shafts. This shifting element engages with gear teeth on both output shafts and redirects torque radially from one shaft to the other when needed. By using this intermediary mechanism with standardized gear interfaces, the patent achieves efficient torque distribution while managing manufacturing precision requirements through conventional gear manufacturing methods.
Data Source
AI summary
A transmission may include an input shaft, a first output shaft, a second output shaft, a first planetary gearset, and a second planetary gearset connected to the first planetary gearset. Optionally, the input shaft is connected to a first element of the first planetary gearset for conjoint rotation, the first output shaft is connected to a second element of the first planetary gearset for conjoint rotation, and the second output shaft is connected to a third element of the second planetary gearset for conjoint rotation. A third element of the first planetary gearset may be connected to a first element of the second planetary gearset via a shaft for conjoint rotation, and a second element of the second planetary gearset may be fixed in place on a non-rotating component.