Vehicle Body Frame Structure with Offset Composite Frames
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Solution Overview
Problem
Conventional vehicle body structures using aluminum pillar frames with closed cross sections face challenges in achieving sufficient steering stability due to the material's lower tensile strength compared to steel, which can hinder weight reduction and design freedom.
Innovation Solution
A vehicle body structure comprising a first frame with a closed cross section made of a material like aluminum and a second frame with a closed cross section made of a higher tensile strength, lighter material like carbon fiber reinforced polymer (CFRP), aligned in the vehicle longitudinal direction, where the second frame's center of gravity is positioned outside the first frame's in the vehicle width direction, enhancing steering stability and reducing weight while maintaining design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the amount of aluminum material is increased to improve tensile strength, then the tensile strength of the vehicle body is improved, but weight reduction of the vehicle body is inhibited
Solution Approach 1:
The patent employs a composite frame structure combining aluminum alloy (first material) and high-tensile-strength material (second material such as CFRP). The aluminum alloy provides weight reduction benefits while the high-tensile-strength material reinforces critical areas to achieve sufficient tensile strength without uniformly increasing aluminum material quantity throughout the entire frame structure.
2Strength
If the cross-sectional shape of the pillar frame is enlarged to improve tensile strength, then the tensile strength of the vehicle body is improved, but freedom of design of the vehicle body becomes difficult due to increase in external dimension
Solution Approach 1:
The patent applies local reinforcement by positioning the high-tensile-strength material (second frame) at specific locations where tensile strength is critical, rather than uniformly enlarging the entire cross-section. The center of gravity of the second frame is positioned on the outer side in the vehicle width direction from the center of the first frame, providing targeted strength enhancement while preserving design freedom in other areas.
3Strength
If a composite frame of first frame and second frame is adopted to reduce weight and improve tensile strength, then vehicle weight is reduced and tensile strength is improved, but external dimensions may increase affecting design freedom
Solution Approach 1:
The patent positions the second frame (high-tensile-strength material) such that its center of gravity is located on the outer side in the vehicle width direction from the center of the first frame (aluminum alloy). This nested configuration allows the high-strength material to be strategically placed within or adjacent to the aluminum frame structure, providing reinforcement without proportionally increasing external dimensions.
Data Source
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AI summary
To provide a vehicle body structure capable of reducing weight of a vehicle body, improving steering stability, and improving freedom of design of the vehicle body, the vehicle body structure includes: a first frame (11) that is formed of a first material and has a closed cross section (11a), and a second frame (12) that is formed of a second material and has a closed cross section (12a). The first frame (11) and the second frame (12) are aligned with each other in a vehicle longitudinal direction (X). The second frame (12) has higher tensile strength and is lighter than the first frame (11). In a front cross-sectional view of the vehicle, center C2 of a drawing of the second frame (12) is located on an outer side (Y1 ) in a vehicle width direction from center C1 of a drawing of the first frame (11) with respect to vehicle center CL.