Dog Clutch Synchronization in Automatic Transmissions
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Solution Overview
Problem
Automatic transmissions face challenges in synchronizing dog clutches, particularly during gear shifts at disparate vehicle speeds, leading to potential damage from unsynchronized engagement and difficulty in achieving smooth, quick synchronization.
Innovation Solution
A method for synchronizing a dog clutch in automatic transmissions by measuring input and output speeds and employing specific processes, including torque management, gear shifting, and actuation of non-positive shifting elements, to ensure smooth and quick engagement across various operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dog clutch is synchronized prior to engaging, then the engagement is smooth and damage is prevented, but the synchronization process is difficult and time consuming
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing the dog clutch components before the actual engagement occurs. The control system monitors rotational speeds and adjusts torque distribution to equalize speeds between the dog clutch elements beforehand, ensuring smooth engagement without grinding or damage while minimizing the time required for synchronization.
Solution Approach 2:
The patent employs feedback mechanisms by continuously monitoring the rotational speeds of dog clutch components and using this information to adjust torque management and synchronization timing. The control system receives feedback from speed sensors and dynamically adjusts the synchronization process to achieve optimal engagement conditions.
2Productivity
If the dog clutch is engaged at disparate speeds (e.g., during hill climbing or rapid acceleration), then the gear ratio changes quickly, but the components may grind against each other and be damaged
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting torque distribution and rotational speed parameters during the synchronization process. The control system modifies torque management parameters to equalize the rotational speeds of dog clutch components before engagement, preventing grinding damage while enabling quick gear changes even during hill climbing or rapid acceleration conditions.
3Speed
If the automatic transmission enters forward or reverse gear at very slow vehicle speeds, then the transmission responds quickly to driver input, but the dog clutch synchronization becomes difficult
Solution Approach 1:
The patent uses an intermediary approach by introducing torque management as a mediating mechanism between the engine and the dog clutch. The control system adjusts torque distribution to facilitate synchronization at very slow speeds, making the engagement process easier while maintaining quick response to driver input for forward or reverse gear selection.
Data Source
AI summary
A method for operating an automatic transmission is provided. The method includes synchronizing a first positive shifting element of the at least one positive shifting element with a first process, a second process or a third process depending upon an input speed and/or an output speed of the automatic transmission. The first process, the second process and the third process can provide smooth and/or satisfactory shifting of the first positive shifting element at various input speeds and output speeds of the automatic transmission.