Non-Synchronized Dog-Shift Transmission Control
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Solution Overview
Problem
Non-synchronized dog-shift transmissions face reliability challenges due to high mechanical component stress and resonance vibrations during gear changes, which can reduce the service life of the selector drum.
Innovation Solution
A method that uses a position sensor on the selector drum to detect its rotational position and transmit it to an electronic control unit, allowing for regulation of the drive engine's rotational speed to a mean value between target speeds when a shift fork is in an intermediate position, with the clutch open, to prevent resonance vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-synchronized dog-shift transmission is used, then the mechanical simplicity and ease of manufacture are improved, but the reliability and service life of the selector drum deteriorate due to high mechanical component stress and resonance vibrations during gear changes
Solution Approach 1:
The control unit detects the intermediate position of the shift fork before the gear change is complete and preemptively regulates the rotational speed of the drive engine to a mean value between the target rotational speeds of the two possible gears. This preliminary speed regulation prevents resonance vibrations from occurring during the critical gear shift phase, thereby protecting the selector drum and improving reliability while maintaining the mechanical simplicity of the non-synchronized transmission
2Device complexity
If a non-synchronized dog-shift transmission is used, then the device complexity is reduced, but the service life of the selector drum deteriorates due to resonance vibrations during gear changes
Solution Approach 1:
A position sensor detects the rotational position of the selector drum and provides feedback to the control unit. The control unit uses this feedback to determine when the shift fork is in the intermediate position and regulates the engine rotational speed accordingly. This closed-loop feedback system enables the complex gear shifting process to proceed smoothly without resonance vibrations, extending the service life of the selector drum while maintaining relatively simple device complexity
Data Source
AI summary
A method is provided for controlling a gear change in the case of a non-synchronized dog-shift transmission having at least one shift fork controllable by way of a selector drum, wherein, by way of a position sensor on the selector drum, the rotational position of the selector drum is sensed and is transmitted to an electronic control unit for controlling a drive motor. By use of the sensed rotational position, the control unit detects whether the/a shift fork is in an intermediate position, in which none of the two possible gears associated with the shift fork is engaged. If the shift fork is in the intermediate position, the rotational speed of the drive motor is controlled to a middle value between the target rotational speeds of the two possible gears if in addition the clutch between the drive motor and the dog-shift transmission is open.