Rear Bumper Structure with Rotating Bracket for Flat Floor
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Solution Overview
Problem
Current vehicle rear bumper structures in A, B, and C segment vehicles cannot accommodate a full flat floor platform due to height and center of gravity constraints, making it difficult to implement a van model that shares a passenger car platform, and existing designs fail to maintain a flat floor when the tailgate is opened, violating van regulations.
Innovation Solution
A rear bumper structure that incorporates a hinge mechanism allowing the tailgate bumper to rotate 90°, featuring a lower side member, upper side member, rear center bumper rotation bracket, crash box, and latch system, which enables a full flat floor platform by adjusting the floor clearance and improving loading convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the floor clearance is raised by about 150 mm or more to achieve a full flat floor platform, then the floor flatness is improved, but the overall height of the vehicle increases and the center of gravity increases
Solution Approach 1:
The patent applies dynamics by making the rear bumper rotatable rather than fixed. The rear bumper can rotate 90 degrees from a horizontal closed position to a vertical open position, allowing the floor clearance to be dynamically adjusted. When the tailgate is closed, the bumper maintains the original floor clearance (350-400mm). When the tailgate is opened, the bumper rotates vertically to create additional clearance space, enabling a full flat floor platform without permanently increasing vehicle height.
2Shape
If the rear bumper structure is made complex with hinge mechanisms and rotation brackets to enable 90° rotation, then the floor flatness is improved, but the device complexity increases
Solution Approach 1:
The patent segments the rear bumper into distinct functional components: a lower side member fixed to the vehicle body, an upper side member that rotates, a rotation bracket connecting them, and a crash box. This segmentation allows each component to perform its specific function - the lower member provides structural support, the rotation bracket enables controlled movement, and the upper member adjusts the floor clearance. By dividing the system into modular segments, the complexity is managed through functional specialization rather than a monolithic complex structure.
Solution Approach 2:
The patent introduces dynamic capability through the hinge mechanism and rotation bracket, allowing the upper side member to rotate 90 degrees relative to the lower side member. This dynamic element transforms the static bumper into an adjustable structure that can adapt between two states: horizontal position for normal driving (maintaining original floor clearance) and vertical position for loaded state (creating full flat floor). The dynamic mechanism is simpler than it appears because it uses a straightforward hinge connection rather than complex actuation systems.
3Reliability
If the latch is inserted into the groove to secure the bumper in rotated position, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The latch mechanism operates on self-service principle where the latch automatically engages with the groove when the upper side member rotates to the vertical position. The gravity and rotational momentum of the upper side member naturally guide the latch into the groove, securing the bumper in the open position without requiring external actuation or complex control systems. Similarly, when the tailgate is closed, the bumper naturally returns to horizontal position and the latch disengages from the groove automatically. This self-service mechanism provides reliable positioning while maintaining simplicity.
Data Source
AI summary
A rear bumper structure includes a lower side member at both sides of a vehicle parallel to a length direction of a floor panel and below the floor panel, an upper side member at both sides of the vehicle parallel to the length direction of the floor panel and above the floor panel and connected to the lower side member by a rear cross member, a bracket having a first end fixed to the lower side member and a second end extending in a bent form toward the rear of the vehicle, a bumper having a first end hinge-coupled to the second end of the bracket and a second end extending in a bent form from the first end toward an outside of the vehicle, and a crash box fixed to the second end of the bumper and coupled to the upper side member.