Sprocket Cover Screwless Crank Integration
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Solution Overview
Problem
Conventional bicycle and electric bicycle chain wheel cover designs require multiple parts and complex assembly processes, making them unsuitable for electric bicycles where there is no rigid rotating connection between the chain wheel and crank.
Innovation Solution
A screwless, rotatably connected chain wheel cover that uses a conical annular extension on the crank to securely attach a metal or plastic cover plate without bolts, nuts, or screws, utilizing deformation such as crimping or gluing for a simplified installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cover is connected using bolts, nuts, or screws, then the connection is secure and reliable, but the number of parts increases and assembly time is extended
Solution Approach 1:
The cover plate is merged with the crank by directly pressing the cover onto the annular extension of the crank, eliminating the need for separate fastening components like bolts, nuts, or screws. This integration reduces the total number of parts while maintaining a secure connection through the deformable material connection between the cover and crank.
2Reliability
If the cover is connected using bolts, nuts, or screws, then the connection is secure and reliable, but assembly time is extended
Solution Approach 1:
The cover plate is designed with a pressing structure that allows pre-alignment and positioning on the annular extension before final deformation. The conical outer contour of the annular extension facilitates preliminary insertion and centering, enabling rapid assembly without requiring time-consuming fastening operations with multiple components.
3Object-affected harmful factors
If the cover plate diameter is larger, then the cover provides better protection, but the distance to the chain bearing area increases
Solution Approach 1:
The cover plate features a localized plate-like recess in the region associated with the crank, creating a varying thickness profile. This local modification reduces the distance between the cover and chain bearing area where proximity is critical, while maintaining adequate coverage and protection in other regions where a larger diameter is beneficial.
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
This solution reduces the number of parts and assembly time, providing a versatile and efficient cover suitable for all types of bicycles, including electric bicycles, with a secure and durable connection.
Implementation Method 1
the cover with the crank is, however, non-rotatably connected by at least partially deforming the material of the pedal crank. Such pressing or crimping, made by means of an appropriate tool, is rapidly generate in a single operation.
Data Source
AI summary
A cover for the sprocket (5) of a bicycle or electric bicycle consists of a cover plate (9) which is arranged between the chain wheel (5) and the equilateral crank (2) and fastened without screws on the inside of the crank.