Automotive Crash Box Coating for Axial Energy Absorption
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Solution Overview
Problem
Existing methods for improving crashworthiness energy absorption in automotive parts, such as front side members and crash boxes, through foaming resins increase manufacturing costs and do not effectively enhance energy absorption during axial crushing.
Innovation Solution
Utilizing electrodeposition paint in the coating process to form a coating film within the tubular member, which prevents fracture and enhances energy absorption by increasing the bending radius during axial crushing, without additional manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If foamed resin is filled inside the automotive part to improve strength and stiffness, then crashworthiness energy absorptive properties are improved, but manufacturing cost increases due to additional filling processes
Solution Approach 1:
The electrodeposition paint system automatically forms a coating film in the gap between the tubular member and inner panel during the normal coating process, without requiring additional filling operations. The system serves itself by utilizing the existing manufacturing process to achieve the energy absorption function.
Solution Approach 2:
The electrodeposition paint serves multiple functions: it provides the intended corrosion protection and surface finish, while simultaneously forming a functional coating film that enhances crashworthiness energy absorption. This multi-functionality eliminates the need for separate filling operations.
2Strength
If foamed resin is filled inside the automotive part to improve energy absorption, then crashworthiness energy absorptive properties are improved, but the additional manufacturing process increases production time
Solution Approach 1:
The coating film formation process is merged with the existing electrodeposition painting process. Both the protective coating and the energy-absorbing coating film are formed simultaneously in a single operation, eliminating sequential processing steps and improving manufacturing efficiency.
3Loss of energy
If the tubular member is made to buckle and deform in bellows shape to absorb energy, then crashworthiness energy is absorbed, but the bending portion may fracture without sufficient bending radius
Solution Approach 1:
The coating film acts as an intermediary layer between the tubular member and the inner panel, providing a cushioning effect that increases the bending radius during deformation. This mediator prevents direct contact and stress concentration, reducing the risk of fracture while maintaining energy absorption capabilities.
4Ease of manufacture
If existing electrodeposition coating process is used to form coating film in gap, then manufacturing cost is controlled, but the coating film thickness must be precisely controlled to achieve optimal energy absorption
Solution Approach 1:
The electrodeposition process inherently provides feedback control through electrical parameters (voltage, current, time) that directly influence coating film thickness. By monitoring and controlling these electrical parameters, precise thickness control is achieved while maintaining cost-effectiveness through the use of standard manufacturing processes.
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
Improves crashworthiness energy absorption and vibration-damping properties while maintaining manufacturing efficiency and reducing costs by using existing manufacturing lines.
Implementation Method 1
a coating layer of electrodeposition paint is formed on the surface, and a coating film is formed when the coating layer is cured by paint baking treatment
Data Source
Figure 1~2
Figure 3~4(b)
Figure 5~6(b)
AI summary
An automotive crashworthiness energy absorption part 1 according to the present invention includes a tubular member 3 formed using a hat-shaped section part including a top portion 7a and a side-wall portion 7b; a coating part 5 that forms a coating film 13 arranged with a gap 11 of 0.2 mm or more and 3 mm or less from an inner surface of the top portion 7a, an inner surface of the side-wall portion 7b, and an inner surface of a corner portion 7c, on a portion including the corner portion 7c connecting the top portion 7a to the side-wall portion 7b in the inner surfaces of the top portion 7a and the side-wall portion 7b, and that is made of a material having strength lower than the tubular member 3; and a coating film 13 of an electrodeposition paint formed in the gap 11.