Vehicle Floor Cross Member Stiffness and Weight Reduction
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Solution Overview
Problem
The existing floor structure of a vehicle body, with a longitudinally extending floor tunnel, lacks sufficient stiffness to withstand side crashes and vertical vibrations, leading to inadequate load distribution and increased weight due to additional bracing components.
Innovation Solution
A body structure featuring a pair of side sills, a front floor panel, a floor tunnel extending longitudinally and bulging upward, and a cross member with a vertical wall that extends continuously between the side sills to close the rear end of the floor tunnel, enhancing stiffness while minimizing the number of parts and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a brace connecting bottom parts of right and left floor panels is provided to pass through a lower part of the floor tunnel, then stiffness of the floor around the floor tunnel is improved, but the number of parts and weight of the vehicle body increase
Solution Approach 1:
The cross member integrates multiple functions: it connects the right and left side sills, supports the rear end of the floor tunnel, and provides structural reinforcement. By combining these functions into a single component rather than using separate braces and support elements, the patent reduces the number of parts while maintaining floor stiffness.
2Strength
If a brace connecting bottom parts of right and left floor panels is provided to pass through a lower part of the floor tunnel, then stiffness of the floor around the floor tunnel is improved, but the weight of the vehicle body increases
Solution Approach 1:
The cross member combines multiple structural functions into one component, eliminating the need for separate braces and support elements. This integration reduces the total material required and consequently decreases vehicle weight while maintaining the necessary floor stiffness.
3Device complexity
If the floor tunnel is provided with a simple longitudinal structure, then the number of parts is reduced, but the load distribution at the time of side crash is insufficient
Solution Approach 1:
The cross member is positioned at the rear end of the floor tunnel to provide preemptive structural reinforcement. This placement ensures that during a side crash, the load is distributed through the cross member to the side sills before the force can concentrate on the floor tunnel, enhancing safety without adding complex components.
4Device complexity
If the floor tunnel is provided with a simple longitudinal structure, then the number of parts is reduced, but vertical vibration of right and left floors cannot be suppressed sufficiently
Solution Approach 1:
The cross member is strategically positioned at the rear end of the floor tunnel to provide preemptive structural support. This reinforcement suppresses vertical vibrations of the right and left floors by creating a rigid connection point, improving stability without adding complex vibration control mechanisms.
Data Source
AI summary
A body structure includes: a pair of side sills separated in the vehicle width direction; a front floor panel provided between the pair of side sills; a floor tunnel extending in the longitudinal direction of the vehicle body at the center in the vehicle width direction of the pair of side sills, and bulging upward from the front floor panel; and a cross member extending in the vehicle width direction at a rear end portion of the floor tunnel, and is characterized in that: the cross member includes a vertical wall extending upward with respect to the front floor panel; and the vertical wall extends continuously in the vehicle width direction between the pair of side sills, is joined to the rear end portion of the floor tunnel, and closes an opening of the rear end portion.