Shift Drum Position Learning via Clutch Release in AMT
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Solution Overview
Problem
Existing gear position learning devices for automatic clutch transmissions do not accurately learn the rotation angle of the shift drum when the transmission is in gear, leading to potential dog hits and inaccurate gear position detection.
Innovation Solution
A gear-position learning device for automatic clutch transmissions that includes a controller to control the connection and disconnection of a clutch device, a shift drum, and a rotational position defining mechanism, allowing precise learning of the shift drum's rotation angle by setting hydraulic pressure and using a stopper to guide the shift drum to defined positions, preventing dog hits and ensuring accurate gear position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the shift drum rotation angle is learned during normal operation, then the learning process is simple, but the learning accuracy is low due to potential dog hits and mechanical interference
Solution Approach 1:
The clutch is pre-disconnected before learning the shift drum rotation angle, eliminating mechanical interference and dog hits during the learning process. This preliminary action ensures the shift drum can rotate freely to its true mechanical position without resistance from the clutch engagement, thereby achieving high learning accuracy.
Solution Approach 2:
The system changes the clutch state parameter from engaged to disconnected during the learning mode. By switching the clutch parameter to a disconnected state, the system creates optimal conditions for accurate rotation angle detection, free from the mechanical constraints present during normal engaged operation.
2Measurement precision
If the clutch is disconnected during learning, then the rotation angle learning accuracy improves, but the learning process becomes more complex
Solution Approach 1:
The system uses feedback from the rotational position defining mechanism (stopper and valley bottom engagement) to automatically determine when the shift drum has reached its correct position. This feedback mechanism simplifies the learning operation by providing clear, automatic termination conditions rather than requiring complex manual procedures.
Solution Approach 2:
The rotational position defining mechanism serves itself by using the stopper and valley bottom geometry to automatically establish the correct shift drum position. The system self-determines the learning completion point through the mechanical engagement of these components, eliminating the need for complex external control during the learning process.
3Measurement precision
If mechanical position defining is used, then the learning accuracy is high, but the device structure becomes more complex
Solution Approach 1:
The stopper acts as an intermediary component that translates the complex rotational position requirements into a simple mechanical engagement with the valley bottom. This intermediary element provides a reliable, easy-to-detect reference point for the learning system without requiring complex sensing or measurement mechanisms.
Solution Approach 2:
The system replaces complex electronic sensing or measurement systems with a simple mechanical position defining mechanism. The stopper and valley bottom geometry provide inherent mechanical reference points that eliminate the need for additional sensors, encoders, or complex electronic position detection systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables highly accurate in-gear position learning by mechanically determining the shift drum's rotational position, preventing dog hits and ensuring precise gear position detection, thereby improving shift accuracy and reducing drive omission variations.
Implementation Method 1
a stopper roller that can engage with the valley bottom of the shift drum plate
Implementation Method 2
a clutch device disposed in a transmission path between the transmission and an engine and configured to be connected and disconnected by actuation of a clutch actuator
Data Source
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AI summary
A gear-position learning device for an automatic clutch transmission includes a transmission configured to be shifted by an operation of a driver of a vehicle, a clutch device disposed in a transmission path between the transmission and an engine and configured to be connected and disconnected by actuation of a clutch actuator, a controller configured to control connection and disconnection of the clutch device performed by the clutch actuator, a shift drum configured to rotate according to a shift operation that the driver performs on a shift operator and switch the shift stage of the transmission, and a rotational position defining mechanism configured to define a rotational position of the shift drum, wherein the controller has a learning mode for learning a rotation angle of the shift drum and is configured to control connection and disconnection of the clutch device during the learning mode such that the shift drum is at a rotational position determined by the rotational position defining mechanism.