Bicycle Frame Inner Tube Nesting for Strength and Weight Reduction
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Solution Overview
Problem
Classical type bicycles made of metallic materials are heavy and lack the strength-to-weight ratio, while modern type bicycles using carbon materials are heavier due to thicker tubes for strength, and there is a need to create a bicycle frame that maintains traditional design with thinner carbon tubes for reduced weight and increased strength.
Innovation Solution
A body frame design featuring outer tubes with uniform circular diameters and inner tubes with polygonal or triangular cross-sections made of carbon material, which are integrated into the outer tubes at specific stress points to reinforce the structure without altering the traditional appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If carbon material is used to reduce weight, then weight decreases, but strength is insufficient when tube diameters are thin
Solution Approach 1:
The patent applies nesting by placing an inner tube inside an outer tube to form a composite structure. The inner tube (made of carbon fiber) is inserted into the outer tube (metallic material), creating a nested configuration that combines the lightweight properties of carbon fiber with the structural strength of metal, thereby reducing overall weight while maintaining sufficient strength.
Solution Approach 2:
The patent uses composite materials by combining carbon fiber (inner tube) with metallic materials (outer tube) to create a hybrid structure. This composite approach leverages the high strength-to-weight ratio of carbon fiber while utilizing the durability and structural integrity of metal, achieving both weight reduction and strength maintenance.
2Shape
If tube diameters are reduced to maintain traditional appearance, then aesthetic quality improves, but strength decreases
Solution Approach 1:
The nested dual-tube structure allows the outer tube to maintain the traditional circular shape and diameter for aesthetic purposes, while the inner tube provides additional structural reinforcement. This nesting enables thin-walled traditional appearance to achieve the strength typically requiring thicker tubes.
Solution Approach 2:
The inner tube is strategically positioned within the outer tube at critical stress areas, providing localized reinforcement where strength is most needed. This allows the overall tube diameter to remain small for traditional appearance while concentrating structural support where mechanically necessary.
3Weight of moving object
If carbon fiber is used to reduce weight, then weight decreases, but manufacturing complexity increases
Solution Approach 1:
The frame is segmented into two distinct tubes (inner and outer) that can be manufactured separately using different processes optimized for each material. The carbon fiber inner tube can be manufactured using carbon molding techniques, while the metal outer tube uses traditional metal forming, allowing each component to be optimized independently before assembly.
Solution Approach 2:
The nested configuration simplifies assembly by allowing the inner carbon fiber tube to be inserted into the outer metal tube, creating a integrated structure through a relatively simple insertion and fixation process rather than requiring complex joint assemblies.
Data Source
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AI summary
Disclosed herein is a frame body (100) for a bicycle which is able to provide higher strength and reduce the weight of the body frame in such a way to use a carbon material even when the outer diameters of a top tube (110), a bottom tube (120), and a seat tube (130), etc. are thinner same as the thickness of the tubes forming the body frame in a classical type bicycle. In the body frame for a bicycle which includes the top tube (110), the bottom tube (120) and the seat tube (130), at least one tube among the top tube (110), the bottom tube (120) and the seat tube (130) is made of a carbon material outer tube of a pipe shape the diameter of which is same from one end to the other end, and an inner tube (300) made of a carbon material in a tubular shape and having a cross section area smaller than the cross section area of the outer tube is fixedly installed in the inside of the whole sections or a predetermined section of the outer tube.