Shift Sleeve Torque Control for Interference-Free Gear Engagement
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Solution Overview
Problem
Current gear shifting methods in dual clutch transmissions and automated manual transmissions experience noise and wear due to mechanical interference and impact between shift sleeve teeth and gear wheel teeth, leading to delayed shifts and reduced transmission lifespan.
Innovation Solution
A control method and system that reduces mechanical interference by using a closed-loop controller to maintain the relative displacement of sleeve teeth and gear teeth within specific phase plane trajectories, employing on-off synchronization torque control and compensation torque to minimize impacts and noise, and can be implemented with existing electronic transmission controllers and actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional mechanical synchronization systems are used with automated shifting actuators, then gear shifting can be automated, but mechanical interference and impact between shift sleeve teeth and gear wheel teeth cause noise, wear, and delayed shifts
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the relative position between the shift sleeve and gear wheel during the synchronization phase. Based on this feedback, the control unit dynamically adjusts the synchronization torque to ensure the sleeve teeth engage with the gear wheel teeth at the optimal moment, minimizing mechanical interference and impact while maintaining automated operation
Solution Approach 2:
The patent dynamically changes the synchronization torque parameter during the gear shifting process. By adjusting the torque magnitude based on real-time position feedback, the system optimizes the engagement process to reduce mechanical impact and noise while maintaining automated shifting functionality
2Speed
If synchronization torque is applied to reduce speed difference between sleeve and gear wheel, then gear engagement can be achieved, but mechanical impact occurs between teeth during engagement
Solution Approach 1:
The control system uses feedback from position sensors to monitor the relative displacement between sleeve teeth and gear teeth. Based on this feedback, the synchronization torque is dynamically adjusted to achieve speed synchronization while preventing excessive impact during tooth engagement, thereby reducing noise and wear
Solution Approach 2:
The system performs preliminary speed synchronization before full engagement by applying controlled synchronization torque to reduce the speed difference between the shift sleeve and gear wheel. This preliminary action prepares the components for smooth engagement, minimizing impact when the teeth finally contact
3Productivity
If gear shift time is reduced for faster shifting, then productivity improves, but mechanical interference increases causing more wear and noise
Solution Approach 1:
The feedback control system enables fast gear shifting by quickly responding to position changes and adjusting synchronization torque in real-time. This allows the system to complete the engagement process rapidly while maintaining precise control, thereby reducing overall shift time without increasing mechanical interference or wear
Data Source
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AI summary
The present disclosure relates to a method for motion control of a shift sleeve in a stepped gear transmission during a synchronization and gear engagement sequence for avoiding gear teeth interference, wherein the stepped gear transmission comprises an axially displaceable shift sleeve arranged on and rotationally secured to a shaft, and a constant mesh gear wheel arranged on and rotatable relative to said shaft, the method comprising: receiving a gear shift command, determining a target relative displacement (y*_sg) between the sleeve teeth (22) and gear teeth (24) for a state when a gear wheel rotational speed (ω_g) reaches a shift sleeve rotational speed (ω_s) at an end of the synchronisation phase, which target relative displacement (y*_sg) is determined for avoiding impact between sleeve teeth and gear teeth during a following gear engagement phase, determining a first phase plane trajectory (y_sg1) defining a relationship between a rotational speed difference (ω_sg) between the shift sleeve and the gear wheel and a relative displacement (y_sg) between the sleeve teeth and gear teeth, wherein the relative displacement (y_sg) according to the first phase plane trajectory (y_sg1) equals the target relative displacement (y*_sg) when said rotational speed difference (ω_sg) becomes zero at the end of the synchronisation phase, determining a second phase plane trajectory (y_sg2) defining the relationship between the rotational speed difference (ω_sg) between the shift sleeve and the gear wheel and the relative displacement (y_sg) between the sleeve teeth and gear teeth, wherein the relative displacement (y_sg) according to the second phase plane trajectory (y_sg2) equals the target relative displacement (y*_sg) when said rotational speed difference (ω_sg) becomes zero at the end of the synchronisation phase, applying a synchronisation torque (T_synch), and controlling said synchronisation torque (T_synch) for keeping the real relative displacement (y_sgr) between the sleeve teeth (22) and gear teeth (24) within the boundaries of the first and second phase plane trajectories (y_sg1, y_sg2) for any rotational speed difference (ω_sg), such that the real relative displacement (y_sgr) between the sleeve teeth (22) and gear teeth (24) reaches said target relative displacement (y*_sg) simultaneously with said rotational speed difference (ω_sg) becomes zero at the end of the synchronisation phase. The present disclosure also relates to a corresponding control system.