Multi-Chamber Crash Box Structure for Protected Bumper Joints
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Solution Overview
Problem
Existing bumper arrangements with crash boxes face challenges in maintaining the integrity of joining connections between crash boxes and crossmembers during crashes, leading to potential damage or destruction of these connections, which can compromise the safety of passengers by affecting the energy absorption and transmission capabilities.
Innovation Solution
The design of a crash box with at least one outer hollow chamber and one inner hollow chamber, where the chambers are connected to form a closed multi-chamber profile at the vehicle-side end but are separated and spaced apart at the bumper-side front portion, providing independent energy dissipation paths and reducing the load on joining connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crash box is screwed to the crossmember with conventional single-chamber design, then the joining connection is subjected to extremely high loading in the event of a crash, but the screw connections are damaged and possibly even completely destroyed
Solution Approach 1:
The crash box is divided into multiple independent hollow chambers (first hollow chamber, second hollow chamber, third hollow chamber) instead of a single chamber. Each chamber can fold and absorb energy independently, distributing the crash forces across multiple separation points and reducing the concentrated load on any single joining connection to the crossmember.
Solution Approach 2:
The hollow chambers are arranged in a nested configuration where the first hollow chamber is positioned at the front, the second hollow chamber is positioned at the rear, and the third hollow chamber is positioned between them. This nested arrangement allows for progressive energy absorption and creates multiple folding zones that distribute mechanical stresses away from the joining connections.
2Device complexity
If the contact surface between crash box and crossmember is reduced, then the joining region is subjected to extremely high loadings, but the joining connections are damaged and possibly even completely destroyed
Solution Approach 1:
The crash box structure is segmented into multiple hollow chambers with partition walls, creating a complex multi-chamber configuration. This segmentation increases the structural complexity but distributes the loading across multiple walls and separation points, preventing concentration of forces at the joining connections.
3Area of stationary object
If the crash box consists of a single-chamber profile with walls bent and joined to crossmember, then the joining regions are subjected to high loadings distributed over a relatively large region, but the joining connections are still damaged and possibly even completely destroyed
Solution Approach 1:
The single-chamber design is replaced with multiple segmented hollow chambers. Each chamber has its own partition walls that create additional separation points and folding zones, distributing the crash forces across more locations and reducing the reliability risk to the joining connections despite the increased contact area.
Solution Approach 2:
The crash box structure transitions from a two-dimensional wall configuration to a three-dimensional multi-chamber arrangement with partition walls extending into the interior space. This dimensional change creates multiple internal separation surfaces that distribute forces in additional directions, protecting the joining connections from concentrated loads.
4Ease of operation
If the hollow chamber is open toward the crossmember, then the folding behavior is considerably less favorable and less predictable, but the joining connections are still subjected to high loadings
Solution Approach 1:
The open hollow chamber is segmented into multiple closed or partially closed chambers separated by partition walls. This segmentation creates defined folding zones within each chamber while the partition walls act as structural supports that guide the folding behavior, making it more predictable and reducing the load transmission to joining connections.
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
This design minimizes the risk of failure in the crash management system and destruction of joining connections, enabling more targeted folding of the crash box and effective energy transmission into the vehicle frame, thereby enhancing passenger safety.
Implementation Method 1
in the event of a crash, to absorb the energy introduced via the bumper arrangement in the crash boxes through corresponding folding or deformation of the crash boxes
Implementation Method 2
absorb the energy introduced via the bumper arrangement in the crash boxes through corresponding folding or deformation of the crash boxes
Implementation Method 3
transmit excess energy into the frame or the vehicle longitudinal member of the motor vehicle
Data Source
AI summary
A crash box for a bumper arrangement of a motor vehicle. The crash box includes at least one outer hollow chamber, at least one inner hollow chamber, a vehicle-side end portion, and a bumper-side front portion. The at least one outer hollow chamber is connected to the at least one inner hollow chamber to form a closed multi-chamber profile in the vehicle-side end portion. The at least one outer hollow chamber is separated and spaced apart from the at least one inner hollow chamber in the bumper-side front portion. In the vehicle-side end portion, the at least one outer hollow chamber and the at least one inner hollow chamber each have a partition which delimits the at least one outer hollow chamber and the at least one inner hollow chamber on an inner side.