Rear Side Member Weak Bead for Rear Collision Load Control
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Solution Overview
Problem
In vehicle rear section structures, during a rear collision, the curved rear cross member can transmit collision loads to the battery or fuel tank, potentially causing adverse effects due to its movement towards the front side, which is not effectively mitigated by existing designs.
Innovation Solution
The design incorporates left and right rear side members with a rear cross member, where first and second weak portions are strategically placed to induce deformation towards the vehicle width direction inner side and up-down direction lower side, thereby suppressing the movement of the rear cross member and reducing the risk of collision load transmission to the battery or fuel tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rear cross member has a curved shape projecting toward the vehicle rear side, then collision energy can be efficiently absorbed, but the rear cross member may be pushed in toward the vehicle front side due to a barrier, causing input in the vehicle lateral direction to act on the rear side member and potentially transmit collision load to the battery or fuel tank
Solution Approach 1:
The patent pre-configures weak portions in the rear side members before collision occurs. These weak portions are strategically positioned to induce controlled deformation toward the vehicle width direction inner side and up-down direction lower side, preparing the structure to redirect collision loads away from the battery or fuel tank when a rear collision occurs
Solution Approach 2:
The patent converts the potentially harmful lateral input to the rear side member into a beneficial controlled deformation. By designing weak portions that induce deformation toward the vehicle width direction inner side and lower side, the harmful lateral collision load is transformed into controlled structural deformation that protects the battery or fuel tank
2Strength
If the rear cross member is pushed in toward the vehicle front side, then collision energy is absorbed by deformation, but movement of the rear cross member toward the vehicle front side is further promoted and collision load is transmitted to the battery or fuel tank
Solution Approach 1:
The patent applies local quality by creating weak portions only in specific locations of the rear side members, rather than uniformly weakening the entire structure. The weak portions are positioned to induce deformation toward the vehicle width direction inner side and lower side, providing localized deformation zones that protect critical components while maintaining overall structural integrity
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 configuration effectively suppresses the influence on the battery or fuel tank by deforming the rear side members to absorb collision energy, preventing the transmission of collision loads and stabilizing the deformation shape, thus enhancing safety during rear collisions.
Implementation Method 1
a first weak portion that is provided at a side toward a joining portion, which joins with the rear cross member, in each rear side member, that is weaker than other portions of the rear side member, and that is set so as to induce deformation of the rear side member toward a vehicle width direction inner side and toward a vehicle up-down direction lower side at a time of a collision from a vehicle rear side
Data Source
AI summary
A rear side member is provided with a first bead that is set so as to be weaker than other portions of the rear side member. The first bead is set so as to induce deformation of the rear side member toward a vehicle width direction inner side and toward a lower side when a collision load is input from a rear cross member at a time of a rear collision of a vehicle, and when the collision load is input from the rear cross member at the time of a rear collision of the vehicle, the rear side member is deformed toward the vehicle width direction inner side, and is deformed toward the lower side, with the first bead as a starting point.