Shift Drum Detent Arm Assembly for Accurate Gear Positioning
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Solution Overview
Problem
Conventional detent mechanisms in gear transmissions require precise positioning and are cumbersome to assemble, as they rely on accurate alignment of the positioning member with the transmission case, which can be challenging and time-consuming.
Innovation Solution
A gear transmission system with a positioning rotation portion and a positioning arm supported by a speed changing operation shaft, utilizing a positioning spring to ensure accurate engagement and simplify the assembly process, where the positioning arm is rotatably supported on the speed changing operation shaft and extended to the positioning rotation portion, allowing for easy alignment and engagement with the positioning action portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional detent mechanism with a positioning member supported to the transmission case is used, then the shift drum can be positioned, but the assembly becomes troublesome and time-consuming due to the need for accurate positioning
Solution Approach 1:
The positioning arm is merged with the speed changing operation shaft by being rotatably supported on it, eliminating the need for a separate support structure on the transmission case. This integration allows the positioning mechanism to be assembled more easily while maintaining accurate positioning through the engagement between the positioning arm and positioning rotation portion.
Solution Approach 2:
The positioning arm acts as an intermediary between the speed changing operation shaft and the positioning rotation portion. By using this intermediate component, the system achieves accurate positioning without requiring direct support from the transmission case, thereby simplifying the assembly process.
2Reliability
If a ball type detent mechanism with through holes in the disc is used, then the cam shaft can be maintained in position, but the positioning member must be precisely aligned with the transmission case which complicates assembly
Solution Approach 1:
The positioning arm is integrated with the speed changing operation shaft through rotational support, combining the support function and positioning function into a single assembly unit. This reduces assembly complexity while ensuring reliable positioning through the engagement mechanism between the positioning arm and positioning rotation portion.
Solution Approach 2:
The positioning arm is made rotatable on the speed changing operation shaft, introducing dynamic capability to the positioning mechanism. This allows the positioning arm to freely rotate and engage with the positioning rotation portion at the correct position, ensuring reliable positioning without requiring precise pre-alignment during assembly.
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 solution enables easy and accurate positioning of the shift drum during assembly, simplifying the assembly process and eliminating the need for a special support member, while also allowing for the detection of multiple operation positions using a single rotation potentiometer.
Implementation Method 1
a positioning spring configured to urge the positioning arm for its engagement to the positioning action portion
Data Source
AI summary
A detent mechanism 70 is provided for fixing a shift drum 58 in position at a rotation operation position where shift gears 36, 37 become engageable. The detent mechanism 70 includes a positioning rotation portion 71 formed in the shift drum 58, a positioning arm 72 engageable with a positioning action portion 74 formed in the positioning rotation portion 71 for fixing the shift drum 58 at a rotation position corresponding to a rotation operation position of the shift drum 58, and a positioning spring 73 for urging the positioning arm 72 for its engagement with the positioning action portion 74. The positioning arm 72, as being rotatably supported to a speed changing operation shaft 61 for rotating the shift drum 58, is extended from a speed changing operation shaft 61.