Front Pillar to Rocker Butt Joint for Collision Load Transmission
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Solution Overview
Problem
Existing vehicle side structures face inefficiencies in transmitting collision loads from the front pillar to the rocker due to deformation at spot welding points, leading to potential load loss and increased deformation during collisions.
Innovation Solution
A vehicle lower portion structure design where the front pillar reinforcement's lower end portion contacts the rocker reinforcement's front end, allowing efficient collision load transmission via a butt joint configuration, with optional ridge line portions for enhanced contact and reduced deformation, and a gap for reduced dimensional accuracy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spot welding is used to join the lower end portion of the front pillar reinforcement to the rocker reinforcement, then the structure is simple and easy to manufacture, but the collision load transmission efficiency is reduced due to deformation at welding points
Solution Approach 1:
The connection between front pillar reinforcement and rocker reinforcement is segmented into two functional zones: an overlapping region for manufacturing simplicity and a butt joint region for efficient load transmission. The lower end portion of the front pillar reinforcement overlaps with the front end portion of the rocker reinforcement, while the extreme ends maintain contact in the vehicle longitudinal direction to ensure direct load path during collision
Solution Approach 2:
Different regions of the connection structure have different functional qualities: the overlapping region provides manufacturing flexibility and positioning, while the butt joint region at the extreme ends provides high-strength direct load transmission. This local differentiation allows each region to optimize for its specific function
2Reliability
If the rear end of the lower end portion and the front end of the rocker reinforcement are always in contact, then collision load transmission is efficient, but the dimensional accuracy and attaching accuracy requirements increase
Solution Approach 1:
The connection structure transitions from a static always-contact configuration to a dynamic configuration where the extreme ends contact only under collision conditions. During normal operation, the overlapping region allows for manufacturing tolerances and positioning flexibility, while during collision, the structural deformation brings the extreme ends into contact for efficient load transmission
Solution Approach 2:
The overlapping configuration is prepared in advance to accommodate manufacturing tolerances and positioning variations. This preliminary arrangement ensures that even with dimensional variations, the structure can still achieve proper alignment and contact at the extreme ends when collision forces are applied
Data Source
AI summary
A vehicle lower portion structure includes a front pillar reinforcement provided to a front pillar and having a lower end portion joined to a panel forming a rocker; and a rocker reinforcement provided to the rocker, joined to the panel, and having a front end that is disposed to face a rear end of the lower end portion from a vehicle rear side, wherein when a collision load is input from a vehicle front side to at least the front pillar, the rear end comes in contact with the front end.