Shift Drum Position Learning for Accurate Automatic Clutch Shifting
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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 errors in gear position detection and shifting performance.
Innovation Solution
A gear-position learning device for automatic clutch transmissions that includes a controller to manage 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 controlling hydraulic pressure and using a stopper mechanism to guide the shift drum to defined positions, thereby avoiding dog hits and ensuring accurate gear position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotation angle of the shift drum is learned during normal operation, then the learning process is simple, but the accuracy of gear position detection is insufficient due to potential dog hits and mechanical interference
Solution Approach 1:
The patent applies preliminary action by performing the learning operation in a predetermined state before normal operation begins. Specifically, the learning is conducted when the clutch is in a disconnected state and the shift drum is positioned at a predetermined position (such as neutral), ensuring that no dog hits or mechanical interference occurs during the learning process. This preliminary setup guarantees accurate detection of the shift drum's rotation angle without the complications that would arise during active transmission operation.
2Measurement precision
If the clutch is disconnected during learning, then accurate rotation angle detection is achieved, but the transmission cannot be operated simultaneously
Solution Approach 1:
The learning operation is performed as a preliminary step before normal transmission operation. The controller learns the rotation angle of the shift drum when the clutch is disconnected and the transmission is in a predetermined state, storing this information for later use. After the learning is complete and the accurate rotation angle is stored, the clutch can be connected and normal operation resumes, thus achieving both accurate measurement and maintained productivity.
3Reliability
If mechanical position defining mechanism is used, then reliable position determination is achieved, but the structure becomes more complex
Solution Approach 1:
The patent utilizes the self-service principle by leveraging the existing mechanical structure of the transmission system itself to define positions. The shift drum's own mechanical features (such as grooves, keys, or engagement points with shift forks) are used to determine predetermined positions like neutral. This approach achieves reliable position determination without adding external position-defining mechanisms, thereby maintaining structural simplicity while ensuring reliability.
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, preventing dog hits and ensuring stable shifting performance by mechanically determining the shift drum's rotational position, thus improving the accuracy and reliability of gear position detection.
Implementation Method 1
the controller (60) is configured to reduce a hydraulic pressure of the clutch device (26) when the stopper (39b) has passed over a top portion (38d) between adjacent valley bottoms (38b)
Data Source
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.