Clamped E-Bike Chainring Assembly for Stable Shaft Mounting
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Solution Overview
Problem
Existing chainring assemblies for electric bicycles fail to securely attach to motor output shafts, leading to potential wobbling and wear during operation, and often require tools that can damage the shaft during removal for maintenance.
Innovation Solution
A chainring assembly with a circumferential ring and spider portion that includes splines matching the motor output shaft's splines, secured by a fastener that clamps the ring onto the shaft, ensuring axial and radial stability and easy removal without damaging the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing chainring assemblies are attached to motor output shafts, then the chainring assembly can be mounted to transmit power, but the attachment is not secure leading to wobbling and wear during operation
Solution Approach 1:
The mounting portion is divided into a circumferential ring and a spider portion with multiple radial arms, creating a segmented structure that can be assembled around the motor output shaft. This segmentation allows the chainring assembly to be securely attached while maintaining operational stability through the distributed support of multiple radial arms.
2Ease of repair
If existing chainring assemblies are attached to motor output shafts, then power transmission is enabled, but tools that can damage the shaft are required for removal during maintenance
Solution Approach 1:
The fastener is designed with a head portion and elongate body that extends through the radial slot, creating a preliminary clamping action that secures the chainring assembly to the motor output shaft. This preliminary securing action allows for easy removal during maintenance without requiring tools that could damage the shaft, as the fastener can be simply removed to release the chainring assembly.
3Reliability
If the chainring assembly is securely clamped to the motor output shaft, then wobbling and wear are prevented, but the attachment mechanism becomes more complex
Solution Approach 1:
The mounting portion merges the circumferential ring and spider portion into a single integrated structure that combines the clamping function with the power transmission function. The splines on the motor output shaft are merged with the mounting portion to provide both securing and rotational coupling, reducing overall device complexity while maintaining attachment security.
Data Source
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AI summary
An electric bicycle (10) includes a frame assembly (14), wheels (18, 22) supporting the frame assembly, a motor assembly (26) coupled to the frame assembly and having a motor output shaft (30), and a chainring assembly (42) including a mounting portion (46) clamped onto the motor output shaft.