Vehicle Front Structure With Rotating Lower Crash Box for Offset Collisions
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Solution Overview
Problem
Existing vehicle front structures are inadequate in managing offset frontal collisions, as they fail to effectively transmit collision loads to the subframe, leading to insufficient load-bearing capacity in the vehicle body front-rear direction.
Innovation Solution
A front structure for vehicles that includes a pair of first crash boxes connected to the front ends of the front suspension members, allowing the crash boxes to rotationally displace towards the vehicle width outer side during an offset frontal collision, thereby improving load distribution and reducing vehicle body deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a horizontally elongated flange is provided on the coupling flange member to suppress deformation during full-wrap frontal collision, then the load-bearing capacity in vehicle body front-rear direction is improved, but the effectiveness in offset frontal collision is insufficient
Solution Approach 1:
The invention changes the connection between the crash box and front suspension member from a fixed rigid connection to a movable connection that allows rotational displacement. The flange portion and bolt configuration enable the crash box to rotate dynamically during offset frontal collision, allowing the front end to move toward the vehicle width outer side and effectively receive and transmit collision loads to the subframe.
Solution Approach 2:
The invention separates the functions of load absorption and load transmission by allowing rotational displacement between the crash box and front suspension member. This segmentation enables the crash box to independently rotate and position itself to receive offset collision loads while still transmitting forces to the subframe through the movable connection.
2Device complexity
If the crash box is rigidly connected to the front suspension member, then the structure is simple, but the collision load cannot be effectively transmitted to the subframe during offset frontal collision
Solution Approach 1:
The invention introduces controlled movement through the movable connection between the crash box and front suspension member. The flange and bolt configuration allows rotational displacement while maintaining structural integrity, creating a dynamic system that adapts to offset collision conditions without excessive complexity.
Solution Approach 2:
The invention changes the connection parameters from completely rigid to partially movable, allowing rotational displacement within specific limits. This parameter change enables the system to accommodate offset collision geometries while maintaining sufficient structural strength for load transmission.
3Reliability
If the crash box is designed for head-on collision absorption, then full-wrap frontal collision protection is achieved, but offset frontal collision protection is insufficient
Solution Approach 1:
The movable connection enables the crash box to dynamically adjust its orientation during offset frontal collision by rotating toward the vehicle width outer side. This dynamic adjustment allows the crash box to effectively intercept and absorb offset collision loads while maintaining its primary function for head-on collision protection.
Solution Approach 2:
The invention introduces asymmetric movement capability through the rotational displacement mechanism. The crash box can rotate asymmetrically toward the vehicle width outer side to accommodate offset collision geometries, while the overall structure maintains symmetry for balanced performance in various collision scenarios.
Data Source
AI summary
A pair of left and right front side members (1) each have a front end to which an upper crash box (4) is fastened via flange portions (1a, 4a). A pair of left and right front suspension members (7) are disposed below the front side members (1). Each of the front suspension members (7) has a front end to which a lower crash box (10) is fastened via flange portions (7a, 10a) by inner and outer fastening portions (13out) arranged diagonally. The upper crash box (4) and the lower crash box (10) respectively have front ends that are connected via a bumper reinforcement side (15). Each of the fastening portions (13in, 13out) is spaced apart from an outer surface of the lower crash box (10) to facilitate deformation of the flange portions (7a, 10a). At a time of a slight-wrap frontal collision, the lower crash box (10) is rotationally displaced in a plan view while the flange portions (7a, 10a) are deformed, to promote lateral shift of a vehicle body.