Bicycle Drive Train With Dual Universal Joint
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Solution Overview
Problem
Bicycles lack efficiency due to the non-driven front wheel, which adds drag and does not contribute to propulsion, especially in off-road operations where power to all wheels would enhance control and ease the cycling process.
Innovation Solution
A multi-wheel bicycle design featuring a dual universal joint connected to both the bicycle frame and steering fork, allowing a front drive chain to power a free-wheeling front hub and rear tire through a drive sprocket, enabling rotational power transfer even during steering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the front wheel is used for steering only, then the steering function is simple and reliable, but the front wheel adds drag and provides no propulsion
Solution Approach 1:
The bicycle drive train is segmented into two independent drive systems: a rear wheel drive system and a front wheel drive system. The front wheel hub is divided into a driven portion (connected to drive chain and sprocket) and a free-wheeling portion (connected to front hub), allowing independent operation of each wheel's propulsion while maintaining the steering function.
Solution Approach 2:
The front wheel is given multiple functions: it serves both as a steering wheel (through the steering fork and handlebars) and as a driven propulsion wheel (through the drive chain and sprocket connection). This multi-functionality eliminates the drag problem by making the front wheel contribute to propulsion while maintaining its steering capability.
2Productivity
If power is provided to both wheels, then propulsion efficiency and control are improved, but the device complexity increases
Solution Approach 1:
The front wheel hub incorporates a dynamic free-wheeling mechanism that allows the front wheel to be driven when power is needed but can disengage and spin freely when not needed. This dynamic capability provides propulsion efficiency when required while avoiding the complexity of permanently coupling the front wheel to the drive system.
Solution Approach 2:
A dual universal joint is introduced as an intermediary component between the frame and the moveable end of the steering fork. This universal joint accommodates the angular movements and misalignments that occur during steering and suspension movement, enabling power transfer to the front wheel without requiring a complex rigid coupling mechanism.
3Power
If the front wheel is connected to the drive chain, then power transfer to the front wheel is achieved, but the connection must accommodate steering movement and terrain variation
Solution Approach 1:
The dual universal joint acts as a mediator between the fixed frame and the moveable steering fork, accommodating angular movements in multiple directions. This allows the drive chain to maintain power transfer to the front wheel while the front wheel independently moves for steering and suspension functions.
Solution Approach 2:
The universal joint allows the connection parameters (angle, position, orientation) to change dynamically as the front wheel steers and the suspension moves, while maintaining continuous power transfer. The joint adapts its configuration to accommodate varying geometric parameters during operation.
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 design allows for efficient power distribution to both front and rear tires, reducing drag and improving control, especially in off-road conditions by maintaining power transfer during steering and varying terrain.
Implementation Method 1
a dual universal joint disposed on a bicycle frame, wherein a first end of the universal joint is mounted to the bicycle frame and a second end of the universal joint is mounted on a moveable end of a bicycle steering fork
Data Source
AI summary
A multi-wheel bicycle with a dual universal joint disposed on a bicycle frame, wherein a first end of the universal joint is mounted to the bicycle frame and a second end of the universal joint is mounted on a moveable end of a bicycle steering fork. A front drive chain is couple from the universal joint to a front tire disposed on a free-wheeling front hub, and a second drive chain is coupled from the first end to a drive sprocket. The drive sprocket is further coupled to a free-wheeling hub attached to a front tire. The coupling provides for transfer of rotational power from the drive sprocket to the front and rear tires through the dual universal joint even as the universal is flexed through its range of motion while steering the bicycle.