Cable-Reinforced Crash Box for Small Overlap Load Transfer
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Solution Overview
Problem
Existing crash boxes in motor vehicles face challenges in effectively managing both low-speed and high-speed crashes, particularly in maintaining structural integrity and preventing damage to fuel lines during small overlap crashes due to inadequate fastening and slippage of strap bands.
Innovation Solution
A crash box design incorporating a cable that extends along the vehicle longitudinal direction, connected to both the crash box and a crossmember via a spring element, ensuring secure fastening and absorption of tensile forces while allowing deformation, thus preventing tearing and maintaining structural integrity during high-speed crashes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If strap bands are installed along the crossmember to distribute load in small overlap crashes, then load distribution is improved, but the connection reliability deteriorates due to slippage and length tolerances
Solution Approach 1:
The patent introduces a cable as an intermediary element between the crash box and the crossmember. This cable acts as a mediator that transmits tensile forces reliably while accommodating length tolerances and preventing slippage, thus resolving the contradiction between load distribution and connection reliability
Solution Approach 2:
The patent changes the mechanical parameter of the connection system by using a cable with specific tensile properties instead of rigid strap bands. This parameter change allows the connection to maintain reliability under load while still distributing forces effectively during small overlap crashes
2Strength
If the crash box connection is reinforced with additional bolts to prevent tearing in high speed crashes, then connection strength is improved, but the compliance with low speed crash requirements deteriorates
Solution Approach 1:
The patent applies local quality by providing reinforcement only where needed - the cable connection provides high strength specifically for preventing tearing in high-speed crashes, while the rest of the crash box structure maintains its original design for low-speed crash compliance. This localized reinforcement avoids the need for overall structural strengthening that would compromise low-speed performance
3Use of energy by moving object
If the crash box structure is weakened to improve energy absorption, then energy absorption capacity is improved, but the structural integrity deteriorates
Solution Approach 1:
The patent segments the structural integrity function from the energy absorption function. The cable provides the necessary structural integrity and connection strength, while the crash box structure itself can be optimized for energy absorption through controlled weakening. This segmentation allows both requirements to be satisfied simultaneously
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 cable-based fastening system enhances the crash box's ability to withstand high-speed crashes by preventing tearing and reduces the risk of damage to fuel lines, while maintaining flexibility for low-speed crashes by avoiding reinforcement that could compromise compliance with low-speed crash requirements.
Implementation Method 1
A crash box (2) for a motor vehicle (1), in particular for a front end of the motor vehicle (1), having a cable (5) which extends along a vehicle longitudinal direction (X) from a front end (22) of the crash box (2) to a rear end (21)
Implementation Method 2
at least one crash box part (2; 21; 22) which is deformable in the event of a crash and which absorbs energy by the deformation thereof in the case of a crash
Data Source
AI summary
A crash box is provided for a motor vehicle having a vehicle longitudinal member which extends in the vehicle longitudinal direction and to the side of which facing away from a passenger compartment of the motor vehicle a rear end of the crash box can be fastened, and having a cross-member which extends in the vehicle width direction and to the side of which facing the passenger compartment of the motor vehicle a front end of the crash box can be fastened. The crash box has a cable which extends along the vehicle longitudinal direction from the front end of the crash box to the rear end of the crash box and is connected to the front end of the crash box and to the rear end of the crash box.