Motorcycle Down Tube Integrated Swing Unit Support
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Solution Overview
Problem
Conventional motorcycle frames face challenges in balancing rigidity and weight, particularly when supporting the swing unit, as they become heavier with additional brackets for pivot movement, compromising traveling performance and manufacturing costs.
Innovation Solution
The motorcycle frame design features hollow down tubes with internally inserted pipes, forming a plate-shaped shaft support section at the rear ends, which increases strength and rigidity while allowing broader support for the swing unit, eliminating the need for separate brackets, thus reducing weight and manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bracket is attached to the down tube to support the swing unit for pivot movement, then the swing unit can be properly supported, but the frame becomes heavier
Solution Approach 1:
The patent merges the bracket function with the down tube by forming a shaft support section directly on the down tube. The down tube is pressed in a plate shape at its rear end to create an integrated support structure that eliminates the need for a separate bracket, thereby reducing frame weight while maintaining swing unit support capability
Solution Approach 2:
The down tube is designed to serve multiple functions: it provides structural support as a frame member and simultaneously serves as a pivot support for the swing unit through the integrated shaft support section. This multi-functionality eliminates the need for separate components
2Strength
If the frame rigidity is increased to withstand forces during pivot movement and twisting forces, then traveling performance improves, but the frame becomes heavier
Solution Approach 1:
The down tube is pressed in a plate shape at its rear end where it needs to provide pivot support, creating a localized reinforcement. This allows the frame to have high rigidity only where needed (at the swing unit support location) while keeping other parts of the frame lighter
Solution Approach 2:
The down tube transitions from a simple cylindrical hollow pipe to a complex shape with a plate-shaped pressed portion at the rear end. This dimensional change creates a thicker, more rigid structure at the critical support point without significantly increasing the overall weight of the down tube
3Reliability
If a bracket is attached to support the swing unit, then the swing unit can be pivotally supported, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent combines the down tube and bracket into a single integrated component. The shaft support section is formed directly on the down tube by pressing it in a plate shape, eliminating the need for separate bracket manufacturing and assembly operations
Solution Approach 2:
The bracket function is extracted from the down tube and integrated into it. Instead of adding a separate component, the necessary support functionality is created by modifying the down tube itself through localized pressing
Data Source
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AI summary
A motorcycle frame comprises shaft support sections (123,124) that support a swing unit for pivot movement. The shaft support sections (123,124) are formed between rear ends of left and right down tubes (103,104). Width that is broad to some extent can be secured at the rear ends of the down tubes (103,104) . The shaft support sections (123,124) for attaching the swing unit are formed at the rear ends of the down tubes (103,104), and thus the swing unit can be supported at a position with a broader width.