Mid-Drive Motor Clutch Transmission for Reverse Pedaling Isolation
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Solution Overview
Problem
The challenge in mid-drive motors is to integrate a clutch device in a compact space that operates reliably under continuous oscillation and disconnects the driving and driven structures when power is off to prevent reverse energy consumption and wear, while ensuring smooth operation and stamina savings.
Innovation Solution
A transmission structure with a clutch assembly comprising a driving ring, clutch gear, output gear, and pressing device, utilizing magnetic attraction and elastic elements to connect and disconnect the motor unit and driven parts, allowing seamless power transmission and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a clutch device is introduced to separate the driving structure and driven structure when motor is power-off, then reverse energy consumption is prevented and component wear is reduced, but the device complexity increases and space requirement increases
Solution Approach 1:
The clutch device is integrated within the transmission housing, merging the clutch mechanism with the existing transmission structure. The driving ring, clutch gear, and pressing device are arranged within the compact transmission space, combining multiple functions into a unified structure that prevents reverse energy consumption without adding separate external components.
Solution Approach 2:
The pressing device acts as an intermediary mechanism that controls the engagement and disengagement of the clutch gear with the output gear. The elastic unit provides automatic pressing force to maintain engagement during power transmission, while magnetic attraction enables rapid disengagement when power is off, mediating between the motor unit and driven structure to prevent reverse driving.
2Duration of action of stationary object
If a clutch device is introduced to separate the driving structure and driven structure when motor is power-off, then component wear is reduced, but the device complexity increases
Solution Approach 1:
The clutch device is integrated within the transmission housing, merging the clutch mechanism with the existing transmission structure. The driving ring, clutch gear, and pressing device are arranged within the compact transmission space, combining multiple functions into a unified structure that protects components from wear without adding separate external components.
Solution Approach 2:
The elastic unit automatically provides pressing force to maintain engagement between the clutch gear and output gear during power transmission, without requiring external control. The magnetic attraction mechanism automatically disengages the clutch when power is off, enabling the system to self-regulate engagement states and protect components from wear without complex external control systems.
3Volume of moving object
If the transmission structure is made compact to fit bottom bracket space, then space utilization is improved, but the available space for clutch device is reduced
Solution Approach 1:
The clutch device components are nested within the transmission housing space. The driving ring is positioned around the clutch gear, which is disposed within the driving ring, and both are integrated with the output gear mechanism. This nested arrangement maximizes space utilization within the compact bottom bracket installation space while accommodating all necessary clutch components.
Solution Approach 2:
The clutch gear is designed to move along the axial direction of the driving ring, utilizing the axial dimension for engagement and disengagement motions. The pressing device applies force in the axial direction, and the magnetic attraction operates along the same axis, effectively using the third dimension to resolve space constraints within the compact radial footprint of the bottom bracket installation.
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 solution ensures efficient power transmission when needed, prevents reverse pedaling, reduces component wear, and maintains stability under oscillation, thereby saving user stamina and extending the motor's lifespan.
Implementation Method 1
The pressing device is magnetic and has a base casing, a pressing disc, and an elastic unit
Implementation Method 2
The elastic unit is located in the mounting space, and the elastic unit abuts the pressing disc and a part of the base casing surrounding the opening
Data Source
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AI summary
A transmission structure of a mid-drive motor has a shell (10), an output axle (20), a motor unit (30), and a clutch assembly (40). The clutch assembly (40) has a driving ring (41), a clutch gear (42), an output gear (43), and a pressing device (44). The driving ring (41) is connected to the motor unit (30). The output gear (43) is detachably connected to the clutch gear (42). The pressing device (44) has a pressing disc (442) movable axially in a base casing (441), and an elastic unit (443) abutting the pressing disc (442) and the base casing (441). The clutch gear (42) drives the pressing disc (442), and the pressing disc (442) pushes the clutch gear (42) to engage with the output gear (43). The pressing disc (442) is reset after separating from the output gear (43) by the pressing device (44).