Shift Drum Mechanism With Slider-Guided Lost Motion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shift-drum speed change operation mechanisms with a lost-motion function require a large operational force and significant axial space due to the need to axially move the fork shaft, locking member, and spring receiving member, making them bulky and force-intensive.
Innovation Solution
The proposed mechanism includes a slider member with a pressing spring that biases it to press the shift fork, allowing the shift fork and shifter member to move between reference and speed change positions with reduced axial movement and operational force, utilizing a slider guide groove to facilitate this movement without obstructing the shift fork's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lost-motion function is implemented by axially moving the fork shaft, locking member, and spring receiving member, then the depression and projection engagement can be completed even in projection abutment state, but the mechanism requires large axial space and significant operational force
Solution Approach 1:
The mechanism is divided into functionally independent segments: the fork shaft assembly (with shift fork and engagement pin part), the slider member assembly (with pressing spring), and the drum member. This segmentation allows the pressing function to be achieved through localized axial movement of the slider member rather than requiring axial movement of the entire fork shaft assembly, thereby reducing the required axial space while maintaining the lost-motion function.
Solution Approach 2:
The slider member acts as an intermediary component between the drum member and the shift fork. It transmits the pressing force from the pressing spring to the shift fork, enabling the lost-motion function without requiring the fork shaft itself to move axially. This intermediary mechanism reduces the operational force needed compared to directly moving the fork shaft.
2Reliability
If a lost-motion function is implemented by axially moving the fork shaft, locking member, and spring receiving member, then the depression and projection engagement can be completed even in projection abutment state, but the mechanism requires large operational force
Solution Approach 1:
The mechanism is divided into functionally independent segments: the fork shaft assembly (with shift fork and engagement pin part), the slider member assembly (with pressing spring), and the drum member. This segmentation allows the pressing function to be achieved through localized axial movement of the slider member rather than requiring axial movement of the entire fork shaft assembly, thereby reducing the required axial space while maintaining the lost-motion function.
Solution Approach 2:
The slider member acts as an intermediary component between the drum member and the shift fork. It transmits the pressing force from the pressing spring to the shift fork, enabling the lost-motion function without requiring the fork shaft itself to move axially. This intermediary mechanism reduces the operational force needed compared to directly moving the fork shaft.
3Force
If the slider member pressing spring biases the slider member to press the shift fork, then the axial movement and operational force are reduced, but the mechanism requires precise coordination of multiple components
Solution Approach 1:
The slider member and pressing spring are combined into a single integrated assembly that works together to provide the pressing force. The slider guide groove in the drum member is designed to coordinate with the axial movement of the slider member, merging the guiding function and pressing function into a coordinated system. This integration simplifies the overall control mechanism compared to separate independent components.
Solution Approach 2:
The mechanism utilizes axial dimension movement of the slider member to achieve the pressing function, rather than requiring rotational or lateral movements. The slider guide groove constrains the slider member to move only in the axial direction, converting a potentially complex multi-dimensional movement into a simple one-dimensional axial movement that is easier to control and coordinate.
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
This configuration reduces the size of the speed change operation mechanism in the axial direction and decreases the operational force required, enabling efficient speed change operations while maintaining the lost-motion function.
Implementation Method 1
a pressing spring that biases the slider member to press the shift fork
Data Source
AI summary
A fork guide groove of a drum member guides a shift fork so that a shifter member is in a reference position not engaged with first and second speed change members when the drum member is placed in a neutral position, is movable between a first speed-change position engaged with the first speed-change member and the reference position when the drum member is placed in a first operational position, and is movable between a second speed-change position engaged with the second speed-change member and the reference position when the drum member is placed in a second operational position. A slider guide groove of the drum member guides a slider member supported by a fork shaft in an axially movable manner so as not to obstruct movement of the shifter member between the reference position and the first speed-change position when the drum member is placed in the first operational position.