Bicycle Hybrid Drive Segmentation for Multi-Mode Operation
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Solution Overview
Problem
Existing hybrid drive systems for bicycles are limited in functionality, as they either fix the electric torque transferred to the wheel hub or make it dependent on the rider's muscle power, lacking versatility in operation modes.
Innovation Solution
A hybrid drive system for bicycles that includes a crank, electric motor, and rear wheel hub shell with an intermediate drive part, featuring a clutch system allowing for both direct and indirect connections, enabling the electric motor and crank to drive the wheel independently or together, and allowing the electric motor to act as a generator for training or charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electric motor is directly connected to the rear wheel hub shell, then the structure is simple, but the functionality is limited and cannot provide multiple operation modes
Solution Approach 1:
The drive system is segmented into three independent connections: crank to intermediate drive part, electric motor to intermediate drive part, and intermediate drive part to rear wheel hub shell. This segmentation allows each component to operate independently or in combination, enabling multiple operation modes (electric assistance, generator mode, direct drive) without increasing overall system complexity.
Solution Approach 2:
An intermediate drive part is introduced as a mediator between the crank/electric motor and the rear wheel hub shell. This intermediary component enables flexible power transmission paths, allowing the system to switch between different operation modes by engaging or disengaging connections at the intermediate drive part, thereby enhancing adaptability without requiring complex control mechanisms.
2Weight of moving object
If the electric motor is positioned inside the rear wheel hub shell, then the weight distribution is improved, but the space for power transmission components is reduced
Solution Approach 1:
The electric motor is nested inside the rear wheel hub shell, with the intermediate drive part positioned within the same space. This nested arrangement allows the motor to contribute to weight distribution improvement while the intermediate drive part efficiently utilizes the available internal space for power transmission, minimizing the volume required for both components.
3Power
If the intermediate drive part is connected to the rear wheel hub shell, then power transmission is efficient, but the bicycle cannot be used on training devices without moving the rear wheel
Solution Approach 1:
The connection between the intermediate drive part and the rear wheel hub shell is made dynamic and reversible. The intermediate drive part can be connected to the hub shell for efficient power transmission during normal operation, and disconnected when the bicycle needs to be used on a training device. This dynamic reconfigurability allows the system to maintain high power transmission efficiency while adapting to different usage scenarios including indoor training.
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
Enhances user functionality by enabling various operation modes, including electric assistance, generator-based training, and energy harvesting, while allowing the bicycle to be used on training devices without moving the rear wheel, and providing adjustable resistance for effective training.
Implementation Method 1
an electric motor (4), in particular having a stator (8) and a rotor (10)
Implementation Method 2
allowing the electric motor to act as a generator for training or charging
Data Source
AI summary
The invention relates to a hybrid drive system for a bicycle comprising a crank, an electric motor, a rear wheel hub shell, an intermediate drive part, a first transmission connecting the crank to the intermediate drive part, and a second transmission connecting the electric motor to the intermediate drive part. The intermediate drive part is connected or connectable to the rear wheel hub shell. The system can include a first clutch between the intermediate drive part and the rear wheel hub shell for in a first mode rotationally coupling the rear wheel hub shell to the intermediate drive part, and in a second mode rotationally decoupling the rear wheel hub shell from the intermediate drive part.