Vehicle Rear Body Support Frame Impact Force Distribution
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Solution Overview
Problem
Existing vehicle rear body structures face challenges in absorbing impact forces during collisions, leading to deformation and potential hydrogen leakage, with existing support frames concentrating stress and causing undue elastic deformation.
Innovation Solution
A vehicle rear body structure design featuring a support frame connected to both the floor frames and rear frames, with a cross member and collar system to distribute impact forces, a rear frame lower member for additional support, and a partition wall to prevent hydrogen leakage, enhancing rigidity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the support frame is connected to the rear brackets and rear frames, then the impact force is transmitted to the side sills and floor frames, but the rear frames and support frame undergo great plastic deformation at central portions
Solution Approach 1:
The invention divides the impact force transmission path into multiple segments by introducing intermediate transmission members (first and second transmission members) between the support frame and rear frames. This segmentation distributes the stress concentration points, preventing great plastic deformation at single central portions while maintaining effective impact force transmission to side sills and floor frames.
Solution Approach 2:
The invention introduces intermediate transmission members as mediators in the force transmission chain. These transmission members act as buffers that distribute and redirect impact forces, preventing direct stress concentration on the central portions of rear frames and support frame, thereby reducing plastic deformation while maintaining overall structural integrity.
2Force
If the support frame is connected to the front end portions of the rear frames, then the impact force is transmitted to the side sills, but the bottom walls of the front end portions are susceptible to deformation or bending due to stress concentration at weld joints
Solution Approach 1:
The invention introduces a first transmission member as an intermediary between the support frame and the front end portions of the rear frames. This intermediate member distributes the impact force away from the weld joints at the bottom walls, preventing stress concentration that would cause deformation or bending, while still enabling effective force transmission to the side sills.
3Adaptability or versatility
If the rear frames have a step-like configuration at front end portions, then the support frame can be incorporated, but the rear frames are likely to deform or bend due to bucking at the step-like portions during rear-end collision
Solution Approach 1:
The invention introduces a second transmission member as an intermediary that connects the support frame to the rear frames at locations that avoid the step-like portions. This intermediate member enables the support frame integration while bypassing the bucking-prone step-like configurations, preventing deformation or bending during rear-end collisions.
4Ease of operation
If the rear frames support the upper ends of the struts, then the suspension units are supported, but the rear frames undergo undue elastic deformation when subjected to large upward thrust
Solution Approach 1:
The invention segments the load-bearing function by introducing transmission members that distribute the upward thrust from the suspension struts. Instead of concentrating all upward forces on the rear frames, the transmission members divide and redirect these forces through multiple paths, reducing undue elastic deformation while maintaining suspension support functionality.
Data Source
AI summary
A vehicle rear body structure includes a support frame of generally rectangular shape attached to side frames of a vehicle body from below for supporting thereon a vehicle part including a fuel tank. The support frame is connected at a front end thereof to floor frames disposed inwardly of the side frames and extending along front parts of the side frames and, at a rear end thereof, to rear frames forming rear parts of the side frames.