Center Frame Vehicle-Body Structure for Distortion Stiffness
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Solution Overview
Problem
Conventional vehicle-body structures without a tunnel portion face reduced stiffness, making it challenging to achieve equivalent distortion stiffness without increasing weight or compromising occupant space comfort.
Innovation Solution
A vehicle-body structure featuring a center frame positioned higher than the floor panel with a downward tilt, connected to the rear portion of the floor panel, and a traveling motor mounted on the rear side with a lower barycenter, enhancing distortion stiffness while minimizing impact on occupant space comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a tunnel portion is provided to improve vehicle body stiffness, then distortion stiffness is improved, but weight increases and occupant space is reduced
Solution Approach 1:
The invention extracts the essential stiffness-providing function from the traditional tunnel portion and relocates it to a center frame structure positioned higher than the floor panel. This separates the stiffness function from the floor panel area, allowing the floor panel to be lighter and the occupant space to be larger while maintaining vehicle body distortion stiffness through the center frame's geometric configuration and connection to the floor panel.
Solution Approach 2:
The invention transitions from a two-dimensional floor panel reinforcement approach to a three-dimensional center frame structure that extends vertically above the floor panel. This dimensional change allows the stiffness function to be provided in the vertical dimension rather than requiring horizontal space in the occupant area, resolving the contradiction between stiffness and occupant space.
2Stability of the object's composition
If a tunnel portion is provided to improve vehicle body stiffness, then distortion stiffness is improved, but occupant space is reduced
Solution Approach 1:
The invention extracts the stiffness-providing function from the floor panel level and relocates it to the center frame positioned in the vertical space above the floor panel. This extraction allows the occupant space at floor level to be maximized while the stiffness function is fulfilled by the center frame's spatial configuration above the occupant area.
Solution Approach 2:
The invention utilizes the vertical dimension above the floor panel to position the center frame, transforming the stiffness solution from a horizontal floor panel feature to a vertical structure. This dimensional transition preserves maximum horizontal occupant space while providing the required distortion stiffness through the center frame's three-dimensional geometry and its connection to the floor panel.
3Stability of the object's composition
If reinforcement members are added to the floor panel to improve stiffness, then distortion stiffness is improved, but device complexity increases
Solution Approach 1:
The invention extracts the reinforcement function from the floor panel itself and relocates it to a separate center frame structure positioned above the floor panel. This separation simplifies the floor panel design while the center frame provides the necessary stiffness through its geometric configuration and single connection point to the floor panel's rear portion.
Solution Approach 2:
The center frame structure serves multiple functions: it provides distortion stiffness, acts as a mounting structure for the traveling motor, and contributes to overall vehicle body rigidity. This multi-functionality reduces the need for separate reinforcement members on the floor panel, thereby reducing device complexity.
Data Source
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AI summary
[Problem] To sufficiently improve the distortion stiffness of a vehicle body with minimized influence on comfort in an occupant space. [Means for Solution] A vehicle-body structure includes a floor panel 41 constituting a floor of an occupant space including a seat on which a passenger sits, and a center frame 80 disposed to be higher than and away from the floor panel 41 at a vehicle-width-direction central portion of the occupant space and extending in a vehicle front-rear direction. The center frame 80 is arranged at a downward tilt toward the vehicle rear side. A rear portion of the center frame 80 is connected to the floor panel 41.