Actuated Locking Differential for Selective Torque Biasing
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Solution Overview
Problem
Traditional differentials fail to optimally distribute torque between front wheels in varying traction conditions, compromising traction, handling, and surface protection, especially in off-road and low-traction scenarios.
Innovation Solution
A locking differential with a torque transfer assembly, ring gear, and actuator that selectively locks or disconnects torque between the driveline and wheels, allowing for automatic or manual configuration changes between two-wheel drive, four-wheel drive, and four-wheel drive lock modes, using connection and disconnect drive dog assemblies to manage torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard differential is used, then torque is sent to the wheel with least resistance, but very little torque can be applied to the wheel with higher traction when one wheel is on low traction surface
Solution Approach 1:
The differential system dynamically adjusts torque distribution between front wheels based on detected traction conditions. The controller receives signals from wheel speed sensors and automatically modifies the differential action to bias torque toward the wheel with greater traction when slippage is detected, while maintaining standard differential operation when both wheels have adequate traction.
Solution Approach 2:
The system incorporates wheel speed sensors that continuously monitor the rotational speed of each front wheel and feed this information back to the controller. Based on this feedback, the controller determines traction conditions and adjusts torque distribution accordingly, creating a closed-loop control system that optimizes traction capability.
2Ease of operation
If both front wheels are disconnected from torque to maximize handling and steering, then handling and steering are maximized, but torque cannot be transferred to front wheels when needed
Solution Approach 1:
The system dynamically switches between disconnected and connected states for the front wheels based on vehicle operating conditions. The controller monitors wheel speed differential and automatically engages torque transfer to front wheels when slippage is detected, while allowing disconnection during normal operation to minimize steering effort and improve handling.
Solution Approach 2:
Wheel speed sensors provide continuous feedback on the rotational speed of front wheels. When the controller detects a significant speed difference between left and right front wheels indicating slippage, it automatically activates torque transfer to the front wheels, ensuring traction capability is maintained when needed.
3Reliability
If a locking mechanism is used to lock both wheels together, then maximum torque transfer is achieved, but steering labor and handling are adversely affected
Solution Approach 1:
The system dynamically adjusts the degree of locking action based on detected slippage conditions. Rather than maintaining a fixed locked state, the controller modulates the locking mechanism to provide just enough torque biasing to prevent slippage while allowing sufficient wheel speed differential for acceptable steering characteristics.
Solution Approach 2:
The locking mechanism's engagement level is continuously adjusted based on operating parameters detected by the controller. When slippage is detected, the locking action is increased to bias torque toward the gripping wheel; when slippage ceases, the locking action is reduced to restore normal steering characteristics and reduce steering labor.
4Reliability
If torque is continuously transferred to front wheels, then traction is improved, but surface protection capability is reduced
Solution Approach 1:
The system applies torque transfer to front wheels periodically and intermittently based on detected slippage conditions rather than continuously. The controller monitors wheel speed differential and activates torque transfer only during periods when slippage is detected, allowing the front wheels to remain disconnected during normal operation to protect sensitive surfaces.
Solution Approach 2:
Wheel speed sensors provide feedback that enables the controller to detect slippage conditions and activate torque transfer only when necessary. This feedback-controlled intermittent operation provides traction improvement during slippage events while minimizing overall torque application to front wheels, thereby reducing surface damage during normal operation on sensitive surfaces.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A locking angle gear box is provided. The locking angle gear box includes a torque transfer assembly, a ring gear, at least one connection drive assembly and an actuator. The torque transfer assembly is configured to communicate torque between the torque transfer assembly and a pair of outputs to halfshafts. The ring gear is rotationally supported on the torque transfer assembly. The ring gear is configured to transfer torque between at least a portion of a driveline and the torque transfer assembly. The at least one connection drive assembly is configured to selectively lock rotation of the torque transfer assembly with the rotation of the ring gear to selectively couple torque between the torque transfer assembly and the ring gear. The actuator is in communication with the at least one connection drive assembly to selectively manipulate the at least one connection drive assembly.