Chainless E-Bike Speed Control for Natural Pedaling Feel
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Solution Overview
Problem
Conventional electric bicycles with chain drive systems have complex structures, especially in multi-wheel configurations like E-CARGO, which complicates the drive system and makes it difficult to achieve a similar driving feel and regulatory compliance.
Innovation Solution
A chainless electric bicycle speed control system using a speed sensor unit, current sensor unit, wheel speed control unit, wheel torque control unit, and pedal torque control unit, which generate torque command values and control currents to manage wheel and pedal torque, allowing for efficient speed control and a driving feel similar to chain-driven bicycles, applicable to both two and three to four wheel vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a chain drive system is used in electric bicycles, then the driving feel similar to conventional bicycles is achieved, but the drive system structure becomes complex especially in multi-wheel configurations
Solution Approach 1:
The patent removes the chain drive system from the electric bicycle, extracting the problematic mechanical connection between pedals and wheels. Instead, it uses a direct drive system where the motor is connected to the wheel hub, eliminating chains, gears, and associated components while maintaining the bicycle's pedaling function through electrical assistance.
Solution Approach 2:
The patent replaces the mechanical chain drive system with an electrical drive system. The motor uses electromagnetic fields to generate rotational force directly on the wheel, substituting mechanical power transmission through chains and gears with electromagnetic power transmission, thereby simplifying the overall drive system structure.
2Adaptability or versatility
If chains and gears are increased to accommodate multi-wheel E-CARGO configurations, then the drive system can handle multiple wheels, but the structure becomes more complex and difficult to maintain
Solution Approach 1:
The patent implements a universal direct drive motor system that can be adapted to different wheel configurations (two-wheel, three-wheel, or four-wheel E-CARGO vehicles) without requiring additional chains or gears. Each wheel can be independently equipped with a direct drive motor unit, providing versatility across multiple vehicle types while maintaining simple structure.
Solution Approach 2:
The patent divides the drive system into independent motor units, with each wheel potentially having its own direct drive motor. This segmentation allows each wheel to be driven independently without requiring a complex centralized transmission system with multiple chains and gears, simplifying the overall structure while maintaining adaptability to different wheel configurations.
3Device complexity
If a chainless drive system is implemented, then the drive system structure is simplified, but speed control becomes more challenging compared to chain-driven systems
Solution Approach 1:
The patent incorporates feedback control mechanisms where sensors detect wheel speed and position, and the control system adjusts motor output accordingly. This closed-loop feedback enables precise speed control in the chainless direct drive system, matching or exceeding the control precision of traditional chain-driven systems while maintaining structural simplicity.
Solution Approach 2:
The patent replaces mechanical speed control mechanisms (such as gear shifts and chain tensioning) with electronic control systems that use sensors and motor controllers to regulate speed. This substitution of mechanical control with electronic control simplifies the physical structure while improving speed control precision and responsiveness.
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
Simplifies the drive system structure, enabling efficient speed control and a driving experience similar to chain-driven bicycles while meeting regulatory standards, and is applicable to various small vehicles with three to four wheels.
Implementation Method 1
a driving force of the pedal is converted into electricity, and the electricity is transmitted to the wheels without the chain
Data Source
AI summary
The present invention relates to electric bicycle speed control device and method. According to the present invention, a torque of a motor for driving a wheel is controlled so that a speed of a pedal driven by a user follows a speed of the wheel, and a torque of the pedal is also controlled by applying an assist level according to the torque of the motor. Therefore, even in an electric bicycle with a chain, it is possible to feel a feeling of the pedal like a bicycle with a chain, and it is possible to adjust the force applied to the pedal according to the assist level.