Bicycle Power Shift Transmission With Dual Shifting and Clutch Preselection
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Solution Overview
Problem
Existing power shift transmissions are bulky and heavy, making them unsuitable for compact and lightweight applications, such as bicycles, where a more efficient power-to-weight ratio is desired.
Innovation Solution
A power shift transmission system with two separate controllable shifting devices that interact directly and indirectly via a clutch, utilizing planetary gear sets and freewheels to achieve a compact and lightweight design, allowing for multiple transmission ratios and preselections, enabling efficient torque transmission in vehicles like bicycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional power shift transmissions are used, then transmission functionality is achieved, but the system becomes large and heavy
Solution Approach 1:
The patent combines multiple shifting functions into a single integrated shifting device that can perform both direct and indirect shifting operations. The shifting device is coupled to the transmission device and can directly shift gears or indirectly shift via the clutch, merging what would traditionally require separate mechanisms into one unified component.
Solution Approach 2:
The single shifting device is designed with universal functionality to perform multiple shifting operations. It can directly shift the transmission device between different gear ratios and also indirectly shift by engaging the clutch for preselection of transmission ratios, making one device perform the work of multiple specialized devices.
2Adaptability or versatility
If multiple shifting devices are used for comprehensive gear shifting, then shifting flexibility is improved, but the transmission becomes more complex and heavier
Solution Approach 1:
The patent merges direct shifting and indirect shifting functions into a single shifting device. This device can operate in two modes: directly shifting the transmission device for immediate gear changes, and indirectly shifting through the clutch mechanism for preselection of transmission ratios, thereby providing comprehensive shifting flexibility with one device.
Solution Approach 2:
The clutch acts as an intermediary element that enables the single shifting device to perform indirect shifting operations. When the shifting device engages the clutch, it can preselect transmission ratios by temporarily disconnecting and reconnecting power flow, providing the same versatility as multiple dedicated shifting devices would offer.
3Volume of moving object
If a compact design is implemented, then weight and size are reduced, but the number of shifting devices must be minimized
Solution Approach 1:
The patent merges multiple shifting functions into a single compact shifting device that integrates both direct and indirect shifting capabilities. This consolidation reduces the overall volume required for the transmission system while maintaining full shifting functionality through one unified mechanism.
Solution Approach 2:
The shifting device is designed with a nested structure where components are arranged concentrically around the drive shaft. The single shifting device incorporates multiple functional elements that can perform both direct and indirect shifting operations, allowing comprehensive functionality within a compact, space-efficient configuration.
Data Source
AI summary
A power shift transmission for a vehicle driveable by motor power and/or pedal power may include a transmission device which transmits a torque introducible on a drive in a transmission ratio settable via a plurality of gears to an output. The power shift transmission may also include two shifting devices via which the transmission device is shiftable for setting the transmission ratio of the transmission device.