Crash Box With Variable Wall Thickness For Oblique Impact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing crash boxes are ineffective in absorbing collision energy when the collision force is applied in oblique directions, as the tubular body tends to bend laterally and fail to enter the side frame, leading to insufficient energy absorption.
Innovation Solution
The crash box is designed with a tubular portion having a base end portion with higher rigidity and an extended portion with lower rigidity, where the base end portion is integrally molded with a pedestal and the extended portion is formed with a smaller thickness side wall, encouraging deformation across a wider range of collision directions. This configuration prevents joint part breakage and enhances energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the tubular body has uniform thickness throughout, then the structure is simple to manufacture, but the rigidity is uniform and deformation is restricted to specific turning points, reducing energy absorption effectiveness in oblique collisions
Solution Approach 1:
The tubular body is designed with non-uniform wall thickness: the first section (near the leading end) has a first wall thickness, while the second section (near the trailing end) has a second wall thickness different from the first. This local variation in thickness creates different rigidity characteristics in different sections, allowing the tubular body to deform more effectively in oblique collisions while maintaining manufacturing feasibility through conventional forming processes.
2Strength
If the tubular body has high rigidity throughout, then the structure is strong and resistant to deformation, but it cannot deform sufficiently to absorb collision energy effectively
Solution Approach 1:
By creating sections with different wall thicknesses, the patent achieves high overall structural strength while allowing specific sections to deform more readily during collision. The varying thickness distribution enables the tubular body to maintain strength where needed while facilitating energy-absorbing deformation in other areas.
3Loss of energy
If the tubular body has low rigidity throughout, then it deforms easily to absorb energy, but the structure lacks sufficient strength and may break at joint parts
Solution Approach 1:
The non-uniform wall thickness design allows sections requiring high strength (such as areas near mounting points) to have greater thickness, while sections intended for deformation have reduced thickness. This localized differentiation ensures the structure maintains sufficient strength overall while enabling effective energy absorption through controlled deformation in specific regions.
Solution Approach 2:
The tubular body is divided into multiple sections with different wall thicknesses, creating a segmented structure where each section has optimized properties for its specific function. This segmentation allows the first section to provide structural support while the second section facilitates energy-absorbing deformation.
4Device complexity
If the tubular body has uniform rigidity, then the structure is simple to design and manufacture, but deformation is restricted to turning points, reducing effectiveness in absorbing oblique collision forces
Solution Approach 1:
The patent introduces local variation in wall thickness to create different rigidity characteristics in different sections of the tubular body. This approach maintains relative design simplicity while significantly improving energy absorption effectiveness by enabling deformation throughout the tubular body structure, not just at discrete turning points.
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
The design effectively absorbs collision energy by allowing the extended portion to deform readily across various collision directions, preventing unintentional breakage and improving energy absorption efficiency.
Implementation Method 1
the extended portion has the smaller thickness than the thickness of the side wall of the base end portion, so that the rigidity of the base end portion is increased to be higher than the rigidity of the extended portion, thereby promoting deformation of the extended portion
Data Source
Figure 1
Figure 2~3
Figure 4A~4E
AI summary
There is provided a crash box comprising a pedestal portion attached to one of two members that are placed in an inward-outward direction of a vehicle; and a bottomed tubular portion integrally molded with the pedestal portion and configured to include a base end portion that is arranged to rise from the pedestal portion and an extended portion that is extended from the base end portion and that has a leading end wall which forms a bottom of the tubular portion and which is attached to the other of the two members, wherein the tubular portion is configured such that a side wall of the extended portion has a smaller thickness than a thickness of a side wall of the base end portion.