Face Gear Shifting Assembly With Split Pinions Under Pedaling Load
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Solution Overview
Problem
Conventional gear shifting systems for bicycles, particularly those using a shaft drive, face inefficiencies and mechanical stress due to the need for multiple pinions and unsynchronized gear changes, leading to friction, wear, and slow shifting, especially during heavy pedaling.
Innovation Solution
A gear shifting system featuring a pinion gear assembly with split sections that can align with multiple gear-rings simultaneously, allowing smooth and efficient gear changes without lateral sliding friction, utilizing a spinner with engaging elements like ball bearings to transmit rotational movement efficiently across concentric gear-rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple pinion gears are used to engage with multiple concentric gear-rings, then gear shifting capability is improved, but device complexity and synchronization difficulty increase
Solution Approach 1:
The pinion gear is divided into multiple independent sections (first pinion section, second pinion section, etc.) that can move independently along the drive shaft. Each section can engage with different concentric gear-rings separately, enabling gear shifting capability while reducing the need for multiple complete pinion gears.
Solution Approach 2:
The pinion sections are given freedom to move along the axial dimension of the drive shaft, in addition to rotating with it. This additional degree of freedom allows each pinion section to independently engage or disengage from different gear-rings by moving axially, simplifying the overall gear shifting mechanism.
2Productivity
If gear shifting is performed during heavy pedaling torque, then continuous power transmission is improved, but friction and wear increase due to lateral sliding
Solution Approach 1:
The pinion sections are designed to be dynamically movable along the drive shaft axis rather than fixed. During gear shifting under load, the pinion sections can move axially to engage or disengage from different gear-rings while maintaining rotational contact, converting what would be lateral sliding friction into controlled axial movement and rolling contact.
Solution Approach 2:
The movable pinion sections act as intermediaries between the drive shaft and the concentric gear-rings. They can selectively engage different gear-rings by axial movement, allowing smooth gear transitions even under heavy pedaling torque by maintaining continuous rotational contact while changing the engaged gear-ring.
3Adaptability or versatility
If shift-channels are used to accommodate gear shifting, then gear change capability is improved, but shifting speed and efficiency decrease
Solution Approach 1:
The pinion gear is segmented into multiple independent sections that can move independently along the drive shaft. This segmentation eliminates the need for restrictive shift-channels, as each pinion section can move freely axially to engage different gear-rings, dramatically increasing shifting speed while maintaining full gear change capability.
4Device complexity
If a single gear-pinion is moved across adjacent gear-rings during gear change, then device simplicity is improved, but additional shifting force is required to overcome friction
Solution Approach 1:
The pinion gear is divided into multiple independent sections that can move separately along the drive shaft. This segmentation reduces the shifting force required because each pinion section moves independently with less mass and inertia, and can engage/disengage from gear-rings separately rather than requiring force to slide a single large pinion across multiple gear-rings.
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
Enables seamless gear shifting without loss of momentum or power, reducing component wear and allowing for gear changes during pedaling without additional pedaling energy, resulting in a more efficient and durable shifting mechanism.
Implementation Method 1
a pinion gear assembly comprising one or more engaging elements and at least two split sections of a spinner
Implementation Method 2
utilizing a spinner with engaging elements like ball bearings to transmit rotational movement efficiently across concentric gear-rings
Data Source
AI summary
A gear shifting system includes a drive shaft, a face gear, and at least one power transmission component(s). The gear system also includes a pinion gear assembly, which is coupled to the first end of the drive shaft. The pinion gear assembly is configured to mesh with one of the concentric gear-rings on the face gear, so that the rotational movement of the gear-ring is transmitted to the shaft. The gear shifting system is easy to operate, mechanically simple, can smoothly shift between gears under any gear shifting conditions, and exhibits decreased component wear.