Gearbox Dog Clutch Control for Stationary Tooth Alignment
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Solution Overview
Problem
In gearboxes with parallel shafts lacking mechanical synchronization means, ensuring proper dog clutch engagement without tooth impact when the vehicle is stationary is challenging, especially in roadside charging mode or when starting from a stop, as the secondary gears may not be stationary, risking tooth collision.
Innovation Solution
The method involves activating a translational movement of the player integral with the secondary shaft towards the pinion without prior synchronization if both parts are stationary, and if not, synchronizing the idler gear with the player before translation, with a rotation at the end of the free flight to align teeth, and using the electric machine to engage the clutch when the threshold is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sliding sleeve is moved to engage the free-running gear without mechanical synchronization means, then the device complexity is reduced, but tooth collision occurs when the gear and sleeve speeds are not synchronized
Solution Approach 1:
The control method performs preliminary speed synchronization by adjusting the torque supplied by drive sources before the sliding sleeve engagement. The system checks if the absolute difference between gear speed and shaft speed is below a threshold, and if not, it adjusts torque to synchronize speeds beforehand, preventing tooth collision during engagement.
Solution Approach 2:
The system continuously monitors the rotational speeds of the free-running gear and secondary shaft, compares them against synchronization thresholds, and provides feedback to the torque control system. This closed-loop feedback ensures speeds are synchronized before engagement, eliminating tooth collision while maintaining a simple mechanical structure.
2Ease of operation
If the vehicle is stopped in roadside charging mode or after shift command, then the secondary gears may remain rotating, but this causes tooth collision risk when sliding sleeve engagement is attempted
Solution Approach 1:
Before attempting engagement at stationary positions, the system performs preliminary speed verification and synchronization. It checks whether the gear and shaft speeds are within the synchronization threshold, and if not, adjusts torque to synchronize them first, ensuring collision-free engagement even when the vehicle is stopped.
Solution Approach 2:
The system dynamically adjusts the engagement strategy based on real-time speed conditions. When speeds are already synchronized, direct engagement proceeds; when not synchronized, the system activates torque adjustment to synchronize speeds first. This dynamic adaptation enables safe engagement in all operational states including stationary conditions.
3Object-affected harmful factors
If torque adjustment is used to synchronize speeds before engagement, then tooth collision is prevented, but the control complexity increases
Solution Approach 1:
The control system uses feedback from speed sensors to continuously monitor gear and shaft speeds, compare them against synchronization thresholds, and adjust torque accordingly. This feedback mechanism prevents tooth collision through intelligent control rather than complex mechanical synchronization devices.
Solution Approach 2:
The patent replaces complex mechanical synchronization means with an electronic control system that adjusts torque to achieve speed synchronization. This substitution uses software-based speed matching and torque control instead of mechanical synchronizers, reducing mechanical complexity while preventing tooth collision.
Data Source
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AI summary
A method for controlling the stationary clutching of an idler gear on a secondary shaft of a parallel shaft gearbox, by movement of a sliding gear constrained to rotate with said shaft towards the idler gear without the intervention of mechanical synchronisation members, characterised in that it involves: - activating the translational movement of the sliding gear towards the idler gear without previous synchronisation, if the two parts are unable to rotate when clutching is requested, and - activating a rotation of the idler gear following the free flight travel of the sliding gear to position the teeth of one in place of the holes of the other, if the clutch engagement threshold has not been crossed following a time delay.