Vehicle Body Rear Structure for Spare Tire Rear-Impact Control
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Solution Overview
Problem
Existing vehicle body rear structures with a horizontally accommodated spare tire are prone to movement towards the passenger compartment during rear impacts, leading to potential interference and instability.
Innovation Solution
A vehicle body rear structure with a floor pan reinforcement member that includes a load support block, a front reinforcement block, and an easy-deformable portion between them, allowing the rear floor pan to bend upward and lift the spare tire forward, thereby stabilizing its movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rear floor pan is designed to be rigid to support the spare tire, then the structural strength is improved, but the spare tire cannot move forward to lift up upon rear impact
Solution Approach 1:
The rear floor pan is divided into a front section and a rear section by introducing an easy-deformable portion. The front section maintains rigidity for structural support, while the rear section can deform forward upon impact to enable the spare tire to lift up, thus resolving the contradiction between overall structural strength and localized deformability needed for tire stabilization.
Solution Approach 2:
The easy-deformable portion is specifically positioned at the rear section of the floor pan to create localized flexibility. This allows the rear section to deform forward under impact while the front section remains rigid, enabling the spare tire to lift up without compromising the overall structural integrity of the floor pan.
2Force
If the rear panel is made collapsible to absorb impact, then the impact energy is reduced, but the spare tire lift-up behavior is restricted
Solution Approach 1:
The floor pan is segmented into collapsible and non-collapsible sections. The rear section with the easy-deformable portion is designed to deform forward to absorb impact, while the front section maintains rigidity to allow the spare tire to lift up freely, thus resolving the contradiction between impact absorption and tire movement control.
Solution Approach 2:
The easy-deformable portion acts as an intermediary element between the collapsible rear panel and the rigid front section. It allows controlled forward deformation to absorb impact while transferring sufficient force to enable the spare tire to lift up, mediating between the conflicting requirements of impact absorption and tire stabilization.
3Strength
If the floor pan reinforcement member extends fully forward to support the spare tire, then the structural support is improved, but the easy deformation upon impact is restricted
Solution Approach 1:
The floor pan reinforcement member is segmented into a front reinforcement portion and a rear reinforcement portion separated by the easy-deformable portion. The front portion extends forward to provide structural support for the spare tire, while the rear portion allows forward deformation upon impact, thus resolving the contradiction between structural support and deformation capability.
Solution Approach 2:
The reinforcement member has different structural properties at different locations: the front portion has high rigidity for structural support, while the rear portion has lower rigidity to enable easy deformation. This local differentiation resolves the contradiction between overall structural support and localized deformation capability.
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
Stabilizes the movement of the spare tire during rear impacts, preventing it from entering the passenger compartment and protecting underlying components like the fuel tank.
Implementation Method 1
an easy-deformable portion with lower bending strength than front and rear regions is provided on a front side of the fixed position of the spare tire in a reinforcement region of the rear floor pan by the floor pan reinforcement member
Data Source
AI summary
A vehicle body rear section includes a rear floor pan (11), a floor pan reinforcement member (20), and a towing load receiving section. The rear floor pan (11) has an upper surface to which the spare tire (16) is fixed. The floor pan reinforcement member (20) is fixed to a lower surface of the rear floor pan (11). The towing load receiving section protrudes downward from a rear section of the rear floor pan (11). The floor pan reinforcement member (20) extends at least partially from a support position of the towing load receiving section toward a front side of a fixed position of the spare tire (16). An easy-deformable portion (22) with lower bending strength than that of front and rear regions is provided in front of the fixed position of the spare tire (16) in a reinforcement region of the rear floor pan (11).