Folding E-Trike Rear-Wheel Drive for Stable Bicycle-Like Handling
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Solution Overview
Problem
Existing electrically-assisted trikes face challenges in combining foldability with stability and rideability due to complex powertrains and zigzag motion from front-wheel pedal propulsion.
Innovation Solution
A folding electrically-assisted trike with a rear-wheel drive configuration, elastomeric torsional element, and offset pedals, along with features like adjustable suspension, tilting steering, and a demountable cargo box, to enhance stability and maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a rear-wheel drive configuration is used, then electrical assistance and power delivery are improved, but the powertrain complexity increases and foldability is precluded
Solution Approach 1:
The trike is divided into separable components including a foldable front assembly and a rear wheel assembly that can be detached. This segmentation allows the powertrain to be simplified in storage mode while maintaining full electrical assistance capability during operation, resolving the contradiction between power delivery and foldability.
Solution Approach 2:
The front assembly incorporates a dynamic folding mechanism with telescopic elements and articulation joints that allow the structure to transition between extended (operational) and collapsed (storage) states. This dynamic configuration enables the powertrain to adapt between complex operational mode and simplified storage mode.
2Device complexity
If front-wheel pedal propulsion is used, then foldability is achieved, but zig-zag motion occurs reducing stability
Solution Approach 1:
The pedal assembly is positioned asymmetrically with respect to the front wheel hub, creating an offset crank mechanism. This asymmetric configuration alters the mechanical advantage and force distribution during pedaling, reducing the zig-zag motion and improving lateral stability while maintaining the foldable front assembly design.
Solution Approach 2:
The pedal assembly position and crank length are optimized to change the mechanical parameters of force transmission. By adjusting the offset distance and crank dimensions, the system minimizes lateral forces that cause zig-zag motion while preserving the ability of the front assembly to fold for compact storage.
3Ease of operation
If an elastomeric torsional element is added to permit front assembly motion, then maneuverability is improved, but device complexity increases
Solution Approach 1:
An elastomeric torsional element is introduced as an intermediary component between the front assembly and rear wheel assembly. This flexible element acts as a mediator that permits controlled relative motion and articulation, improving maneuverability while avoiding the need for complex mechanical linkages, joints, or actuators that would increase overall device complexity.
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 trike achieves improved safety and ease of use by simulating bicycle dynamics, providing stable and comfortable rides with enhanced maneuverability and foldability, suitable for various transportation needs.
Implementation Method 1
An elastomeric torsional element may be used to connect the front assembly and the rear assembly. The elastomeric torsional element can be configured to permit a range of motion of the front assembly relative to the rear assembly, about a longitudinal axis referenced to the transportation device.
Data Source
AI summary
A transportation device is disclosed. One aspect includes a rear assembly that further includes a rear frame, and a first rear wheel and a second rear wheel mounted to the rear frame. The rear assembly may also include a first electric motor and a second electric motor mechanically connected to the first rear wheel and the second rear wheel respectively, and an electrical power source comprising a battery, configured to power the first electric motor and the second electric motor. The transportation device may also include a front assembly that includes a saddle and a front wheel connected to the saddle via a wheel hub and a fork. An aspect includes an elastomeric torsional element connecting the front assembly and the rear assembly.