Shift Drum Control Using Dual Angle Sensing and Play Learning
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Solution Overview
Problem
Existing transmission apparatuses with dual-clutch transmissions require a complex structure and numerous components to accurately control the rotation of the shift drum, leading to increased costs and complexity.
Innovation Solution
A transmission apparatus with a simplified variable speed drive mechanism that eliminates the pole ratchet mechanism and reduces the number of components by using a drum center, stopper mechanism, shift driven gear, shift spindle, and sensors to accurately control the shift drum rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pole ratchet mechanism and speed increasing mechanism are added to accurately detect the rotation angle of the shift drum, then the measurement precision of the shift drum rotation angle is improved, but the device complexity and number of components increase
Solution Approach 1:
The patent extracts and eliminates the complex pole ratchet mechanism and speed increasing mechanism from the variable speed drive mechanism. Instead of using these additional mechanisms, the invention directly couples the shift drum with the shift fork, allowing the shift drum's own rotation to drive the speed increasing function without requiring separate mechanisms for angle detection and speed transformation.
Solution Approach 2:
The shift drum is given multiple functions: it serves as both the rotation element for gear shifting and the detection element for rotation angle measurement. The shift drum's rotation directly drives the shift fork while simultaneously being detected by a single angle sensor, eliminating the need for separate detection mechanisms for sensor shafts.
2Adaptability or versatility
If the number of gear positions of the shift drum is increased to provide more shift stages, then the adaptability of the transmission is improved, but the intervals between gear positions become narrower and the device complexity increases
Solution Approach 1:
The patent segments the speed increasing function from the rotation control function. By using a shift drum with fewer positions that directly drives a shift fork with segmented speed increasing capability, the system can achieve multiple shift stages without requiring the shift drum itself to have numerous closely-spaced positions. This segmentation allows broader gear position intervals while maintaining multiple shift stages.
Data Source
AI summary
A control value is corrected and learned based on a difference angle Δφ between a drum shaft conversion spindle integration angle φs obtained by converting a detected spindle angle detected by a spindle angle sensor 78 into a drum angle and a detected drum angle φd detected by a drum angle sensor 89, over a predetermined learning time T from when the shift motor 61 is driven, and a drive engagement portion 83d of a shift driven gear 83 reduces the play angle to abut on a driven engagement portion 82d of a drum center 82 to accompany the driven engagement portion 82d. In this manner, rotation of a shift drum 80 can be accurately controlled by the shift motor 61, while the number of components of a variable speed drive mechanism 60 is reduced.