Bicycle Electric Assist Device Modular Retrofit
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Solution Overview
Problem
Conventional bicycle electric power assist devices require extensive disassembly and specialized tools for retrofitting, making it difficult for ordinary users to convert existing bicycles into electric power assisted bicycles, and they lack versatility across different bicycle models.
Innovation Solution
A bicycle electric power assist device with a housing supported by the bicycle frame, featuring an electric motor, battery, annular rotational output member, and a transmission gear train, which allows for easy retrofitting without modifying the bicycle, using a connecting member that slides along the crank arm for torque transmission, and includes a rotational output plate to protect the output gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bicycle electric power assist devices are retrofitted to existing bicycles, then electric power assistance is provided, but extensive disassembly and specialized tools are required making installation difficult
Solution Approach 1:
The device is divided into separate modular components: a crank arm unit with the electric motor integrated, a sprocket unit with the drive gear, and a chain connecting them. This segmentation allows each component to be independently installed and positioned, eliminating the need for extensive disassembly of the original bicycle components and reducing installation complexity while maintaining reliable power assistance.
2Reliability
If conventional bicycle electric power assist devices are retrofitted to existing bicycles, then electric power assistance is provided, but specialized tools are required for installation
Solution Approach 1:
The crank arm unit and sprocket unit are designed with self-aligning features and standard interfaces that allow ordinary users to install the device using only common tools. The modular design with clear assembly sequences enables users to complete the retrofit without requiring specialized technical knowledge or proprietary tools, while ensuring reliable electric power assistance functionality.
3Reliability
If conventional bicycle electric power assist devices are retrofitted to existing bicycles, then electric power assistance is provided, but versatility across different bicycle models is limited
Solution Approach 1:
The device employs universal mounting interfaces and standardized component connections that can be adapted to various bicycle frame types and crank arm configurations. The modular crank arm unit and sprocket unit design allows the same basic device to be installed on different bicycle models, enhancing versatility while maintaining reliable electric power assistance across diverse applications.
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
Enables the conversion of a wide range of existing bicycles into electric power assisted bicycles with ease, without the need for special tools or modifications, ensuring a simple and effective installation process.
Implementation Method 1
an electric motor (54) attached to the housing (52)
Implementation Method 2
a transmission gear train (59) received in the housing (52) to transmit a rotational motion of the electric motor (54) to the rotational output member (81)
Implementation Method 3
the connecting member (130) is a staple-shaped connecting member fixed to the rotational output plate (84), the connecting member (130) projecting laterally outward from the rotational output member (81) and interposing a base end part of the crank arm (26) from front and rear sides with respect to a rotational direction thereof so as to be in contact with a front surface (26A) and a rear surface (26B) of the crank arm (26)
Data Source
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AI summary
A wide range of existing bicycles can be converted into electric power assisted bicycles with ease. The bicycle electric power assist device comprises a housing (52) configured to be attached to a frame (18) of a bicycle (10), an electric motor (54) attached to the housing (52), a battery (102) configured to be mounted to the frame and serves as a power source for the electric motor, an annular rotational output member (81) rotationally driven by the electric motor (54), the rotational output member being rotatably mounted on the housing and positioned around a crank axis line which is a rotational center line A of a crankshaft (24) and a crank arm (26) for a pedal of the bicycle, and a connecting member (90) connecting the rotational output member (81) to the crankshaft (24) or the crank arm (26) in a torque transmitting relationship.