Dual Rear-Wheel E-Bike Drive Without Gearbox Bulk
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Solution Overview
Problem
Existing ride-on vehicles lack operational efficiency, ergonomics, safety, and stability, particularly in varying conditions, and require complex structures and high power assistance without compromising autonomy.
Innovation Solution
A pedal-assisted vehicle with two independent electric motors, each connected to a rear wheel via a suspension, allowing synchronized or differential operation, and a simplified structure without a gearbox, using compact components for enhanced power assistance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single more powerful electric motor is used to provide high assistance power, then the power assistance is improved, but the vehicle bulk and complexity increase
Solution Approach 1:
The patent divides the single motor system into two separate electric motors, each integrated with a rear wheel. This segmentation allows the system to achieve high total power output while keeping each individual motor compact, thereby reducing overall vehicle bulk and improving operational efficiency
2Power
If a single more powerful electric motor is used to provide high assistance power, then the power assistance is improved, but the device complexity increases
Solution Approach 1:
The patent segments the powertrain into two independent motor-wheel units, eliminating the need for a complex gearbox and transmission system. Each motor is directly integrated with its corresponding wheel, simplifying the overall mechanical structure while maintaining high power capability
Solution Approach 2:
Each electric motor serves multiple functions: it provides propulsion power, integrates with the wheel structure, and works independently or in coordination with the other motor. This multi-functionality reduces the need for additional components and simplifies the overall system architecture
3Productivity
If high power assistance is provided to assist user pedaling, then the operational efficiency is improved, but the battery autonomy is compromised
Solution Approach 1:
The patent divides the power delivery across two independent motors, allowing for more efficient energy distribution and recovery. The regenerative braking system on each wheel independently captures kinetic energy, improving overall energy recovery efficiency and extending battery autonomy while maintaining high operational efficiency
Solution Approach 2:
The electronic controller monitors the operational state of both motors and the battery system, dynamically adjusting power delivery to optimize the balance between operational efficiency and battery conservation. This feedback mechanism ensures high performance when needed while preserving autonomy for extended operation
4Speed
If the vehicle is designed for high speed operation, then the speed performance is improved, but the safety and stability deteriorate on slippery or bumpy roads
Solution Approach 1:
The patent uses two independently controlled electric motors, one for each rear wheel, allowing differential control of wheel rotation. This segmentation enables individual wheel adjustment to maintain traction and stability on slippery or uneven surfaces while preserving high speed capability on suitable roads
Solution Approach 2:
The electronic controller dynamically adjusts the operation of each motor based on real-time conditions, enabling the vehicle to adapt to varying road surfaces and maintain optimal stability and safety while preserving speed performance when conditions allow
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 vehicle achieves high operational efficiency, safety, and flexibility across different conditions, with extended autonomy and reduced bulk, while ensuring comfort and stability, suitable for various applications including personal mobility devices and cargo bicycles.
Implementation Method 1
two mutually independent electric motors (M1, M2) associated with the two rear wheels (7) on the axes of these wheels
Implementation Method 2
two independent elastic members (13) are provided, each interposed between a respective longitudinal arm (8) and the frame (2)
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A ride-on type pedal-assisted vehicle comprises two rear side- by-side wheels (7), with which two electric motors (M1, M2) for pedaling assistance are associated, each on the axis of the respective rear wheel (7), and having respective rotors (R) not connected to each other. In a first solution, the pedal crank assembly (10) is connected by means of a chain transmission (14) solely to the rotor (R) of a first electric motor (M1). An electronic controller (E) controls the first electric motor (M1) according to the torque applied by the user to the pedal crank assembly (10) and the second electric motor (M2), adapting it to operate at the same rotation speed as the first electric motor (M1). In a second solution, the pedal crank assembly (10) is connected via a chain transmission (14) to the rotor (R) of the first electric motor (M1) and via a further chain transmission (14) to the rotor (R) of the second electric motor (M2).