Vehicle Bumper Brace and Set Plate for Crash Can Rotation
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Solution Overview
Problem
In vehicles with a relatively high height, such as SUVs, the concentration of collision load at the lower bumper can cause the bumper reinforcement and crash cans to rotate downward, making it difficult to maintain repairability in light vehicle collisions, as existing strengthening connections can lead to deformation and require more extensive repairs.
Innovation Solution
A vehicle-body structure featuring a pair of crash cans spaced apart in the vehicle width direction, connected by a bumper reinforcement, with a set plate between the crash cans and the vehicle-body side frame, and an obliquely extending brace that forms a space between the brace and the crash can, fixedly joined to the bumper reinforcement's lower face, preventing downward rotation and supporting the bumper reinforcement with a vertical face portion to suppress arch-shaped deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connection of the bumper reinforcement to the vehicle-body side frame is strengthened to prevent downward rotation in high-vehicle collisions, then the stability and strength are improved, but the repairability deteriorates because the strengthened connection influences the vehicle body even in light vehicle collisions
Solution Approach 1:
The connection structure is divided into two independent parts: (1) the set plate connecting the crash can to the vehicle-body side frame, and (2) the brace connecting the bumper reinforcement to the set plate. This segmentation allows the brace to be replaced independently in light collisions without affecting the set plate and vehicle-body side frame connection, thereby maintaining repairability while providing sufficient support through the combined structure.
Solution Approach 2:
The set plate serves as an intermediary component between the crash can and the vehicle-body side frame, and the brace serves as an intermediary between the bumper reinforcement and the set plate. This intermediary structure allows the collision load to be transmitted through the set plate to the vehicle-body side frame without requiring direct strengthened connection between the bumper reinforcement and the vehicle-body side frame, thus preventing downward rotation while maintaining ease of repair.
2Strength
If a gusset extending obliquely rearwardly is provided between the rear bumper beam and the set plate to transmit load, then the strength is improved, but the repairability deteriorates because the gusset has a vertical height equivalent to the entire crash can, causing the rear bumper beam and crash can to move rotationally downwardly together with the gusset
Solution Approach 1:
Instead of using a single gusset that spans the entire vertical height of the crash can, the connection is segmented into the set plate (attached to the vehicle-body side frame) and the separate brace (attached to the bumper reinforcement). This segmentation prevents the bumper reinforcement and crash can from moving rotationally downwardly together, as the brace provides support at a lower position without compromising the overall load transmission capability.
Solution Approach 2:
The set plate acts as an intermediary component that receives the load from the crash can and transmits it to the vehicle-body side frame, while the brace acts as an intermediary that provides additional support to the bumper reinforcement. This dual-intermediary structure allows the load to be transmitted effectively without causing the bumper reinforcement and crash can to move rotationally downwardly together, thus maintaining repairability.
Data Source
AI summary
A vehicle-body structure comprises a pair of right-and-left crash cans provided at an end portion of a vehicle body, being spaced apart from each other in a vehicle width direction, a bumper reinforcement extending in the vehicle width direction and connecting respective tip portions of the crash cans, set plates interposed between each of the crash cans and a vehicle-body side frame, wherein each of the crash cans is fixed to the vehicle-body side frame via the set plates, and a brace extending obliquely, in a plan view, from an inward side, in the vehicle width direction, of the crash can or the set plate to the bumper reinforcement such that a space is formed, in the vehicle with direction, between the brace and the crash can. The brace is fixedly joined to a lower face of the bumper reinforcement.