Selection Shaft Gearshift with Integrated Pawl Blocking
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Solution Overview
Problem
Existing gearshift devices for mobility vehicles, such as electrically assisted bicycles, are complex and require many parts, making them difficult to manufacture and maintain, particularly due to the need for precise and regular adjustment of cable controls.
Innovation Solution
A gearshift device with a selection shaft housing a shuttle and a worm, featuring input and output pinions, pawls with lifter devices, and a radial blocking system formed as a single piece to simplify manufacturing and reduce costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional cable control system is used for gear shifting, then the gear selection can be achieved, but the device complexity increases and manufacturing cost rises
Solution Approach 1:
The patent removes the cable control system and its associated adjustment mechanisms from the gearshift device. The cable, housing, and adjustment components are extracted and replaced with a direct actuation system where the actuator directly moves the selection shaft, eliminating the intermediary cable control mechanism.
Solution Approach 2:
The patent combines multiple functions into integrated components. The selection shaft integrates the selection mechanism with the gear engagement mechanism, and the actuator directly couples to the selection shaft, merging the control and execution functions into a unified system that reduces part count.
2Ease of operation
If a traditional cable control system is used for gear shifting, then the gear selection can be achieved, but the manufacturing and maintenance difficulty increases
Solution Approach 1:
The patent extracts the cable control system which requires precise adjustment and regular maintenance, replacing it with a direct actuation system that eliminates adjustment mechanisms, thereby simplifying both manufacturing and maintenance procedures.
Solution Approach 2:
The new system is designed to be self-adjusting, eliminating the need for manual cable adjustment. The direct mechanical connection between actuator and selection shaft automatically maintains proper engagement without requiring user intervention or specialized maintenance.
3Ease of operation
If a traditional cable control system is used for gear shifting, then the gear selection can be achieved, but the adjustment precision requirement increases
Solution Approach 1:
The patent removes the cable control system that demands high adjustment precision, replacing it with a direct actuation system where the actuator's movement directly translates to selection shaft displacement, eliminating the need for precise cable tension and length adjustments.
Solution Approach 2:
The patent replaces the flexible cable mechanical control system with a direct rigid or semi-rigid mechanical connection. This substitution eliminates the precision adjustment requirements inherent in cable systems while maintaining the gear selection functionality.
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
The proposed gearshift device simplifies the gear shifting mechanism, reduces manufacturing complexity and costs, and eliminates the need for precise cable adjustments, resulting in a more reliable and easier-to-maintain system.
Implementation Method 1
a worm (21) arranged so as to convert a rotation around an axis into a translation along an axis perpendicular to the first axis
Implementation Method 2
a gearshift actuator (70) arranged so as to displace the shuttle (41) along the worm (21) between at least two positions
Data Source
AI summary
The invention relates to a gear shift device for a mobility vehicle, comprising: —a selection shaft in which a shuttle and a worm are arranged, —at least two input pinions arranged to rotate freely about the selection shaft, —at least two output pinions coupled in rotation with a hollow shaft, —a gear shift actuator arranged to move the shuttle along the worm between at least two positions, and to engage a selected gear ratio, —at least two pawls arranged on the selection shaft, each pawl being associated with a lifting device for lifting the pawl via the shuttle, and to engage the gear ratio selected via the input and output pinions, the device comprising a radial blocking system, which is formed in one piece, for keeping all the pawls in place on the selection shaft.