Shift Drum Angle Sensing With Offset Switching for Stable Gear Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shift drum angle detecting devices face challenges in precisely detecting the rotational angle of a shift drum with increased gear positions, leading to unstable output from sensors and influence on actuator control, especially when lead grooves extend beyond 360 degrees and gear positions are axially displaced.
Innovation Solution
A shift drum angle detecting device is designed with a first sensor shaft and a second sensor shaft that rotate at different speeds, using sensors to output values that switch between maximum and minimum values at specific angles, ensuring precise detection by avoiding simultaneous switching and setting these angles within the neutral position region to minimize actuator control influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of gear positions is increased and lead grooves are formed past 360 degrees with axial displacement, then the gear position capacity is improved, but the sensor output stability deteriorates due to simultaneous switching of first and second angle sensors
Solution Approach 1:
The patent applies preliminary action by pre-setting the first sensor switching angle and second sensor switching angle to be different from each other before the transmission operates. This prevents the simultaneous switching problem in advance, ensuring that at least one sensor always provides stable output even when detecting rotations past 360 degrees with axial displacement of lead grooves.
2Reliability
If the first sensor switching angle and second sensor switching angle are set to be different, then the sensor output stability is improved, but the device complexity increases due to additional angle offset configuration
Solution Approach 1:
The patent applies parameter changes by modifying the switching angle parameter of the sensors. Specifically, it sets the first sensor switching angle and second sensor switching angle to different values (introducing an angle offset), which changes the operational characteristics of the sensor system to avoid simultaneous switching while maintaining detection accuracy.
3Quantity of substance
If lead grooves are formed past 360 degrees to accommodate more gear positions, then the gear position capacity is improved, but the manufacturing precision requirement increases to maintain smooth shift fork movement
Solution Approach 1:
The patent applies dimensionality change by extending the lead grooves past 360 degrees in the rotational dimension and introducing axial displacement. This allows the shift drum to accommodate more gear positions (15 positions at 24 degrees interval) by utilizing both rotational and axial dimensions, thereby increasing gear position capacity without requiring an larger shift drum outer diameter.
Data Source
AI summary
A shift drum angle detecting device includes: a first angle sensor configured to output a first sensor output value corresponding to a shaft rotational angle of a first sensor shaft integrally rotating with a shift drum; and a second angle sensor configured to output a second sensor output value corresponding to a shaft rotational angle of a second sensor shaft rotating at an increased speed as a result of a speed increasing mechanism increasing the rotation of the first sensor shaft. A first sensor switching angle where the maximum value and the minimum value of the first sensor output value are switched and a second sensor switching angle where the maximum value and the minimum value of the second sensor output value are switched are set to be different from each other in rotational angle of the shift drum. Such device precisely detects any rotational angle of the shift drum.