Vehicle Floor Frame Reinforcement for Load Distribution

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Solution Overview

Problem

Conventional vehicle floor frame structures in small vehicles with compact designs face challenges in transmitting loads from the front to the rear without bending or increasing weight, often resulting in inadequate rigidity and potential buckling deformation due to stress concentration at the rear floor's front portion.

Innovation Solution

A vehicle floor frame structure featuring a reinforcement extending in the vehicle body front-and-rear direction, disposed above the floor side members with a hat-like cross-sectional shape, forming closed section spaces that distribute the load from the front side to the rear floor panel, preventing buckling deformation and stress concentration by increasing rigidity and allowing efficient load absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If side members are positioned on outer sides in the vehicle body width direction to avoid interference with fuel tank and rear tire suspensions, then the distance between side members increases, but the rigidity of the floor frame structure decreases

Engineering Contradiction:

Improveavoidance of interference with fuel tank and rear tire suspensionsVSAvoidrigidity of floor frame structure

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The side member is divided into two separate members: a floor side member for the main floor and a rear side member for the rear floor. This segmentation allows each member to be positioned optimally for its specific function while maintaining overall structural rigidity through proper connection design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes the vertical dimension by positioning the floor side member and rear side member at different height levels. The floor side member is located at the main floor level while the rear side member is positioned higher to avoid interference with the fuel tank and rear tire suspensions, thus resolving the spatial conflict without compromising rigidity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If additional members are provided to transmit load from front to rear, then load transmission is improved, but the weight of the vehicle increases

Engineering Contradiction:

Improveload transmission capabilityVSAvoidvehicle weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The floor side member and rear side member serve multiple functions: they provide structural support for their respective floors, transmit loads from the front to the rear, and avoid interference with underlying components. This multi-functionality eliminates the need for additional dedicated load transmission members, maintaining lightweight design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs curved portions in the side members that allow controlled deformation under load. These curved portions act as flexible load transmission paths, enabling the structure to absorb and transmit forces dynamically without requiring additional rigid reinforcing members.

Inventive Principle:

Principle #15Dynamics

3Reliability

If curved portions are formed in side members to transmit load, then load absorption is improved, but stress concentration occurs in the curved portions

Engineering Contradiction:

Improveload absorption capabilityVSAvoidstress concentration in curved portions

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent applies different geometric characteristics to different portions of the side members. The curved portions are designed with specific radius and transition angles to distribute stress evenly, while the straight portions maintain high rigidity. This local optimization prevents stress concentration while maintaining load absorption capability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The side members incorporate carefully designed curved portions with optimized radius of curvature. These curved sections smoothly transition between straight portions, creating continuous stress flow paths that minimize stress concentration while effectively absorbing and transmitting loads from the front to the rear of the vehicle.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS8820819B2Vehicle floor frame structure

Publication Date: 2014.09.02 SUZUKI MOTOR CORP

AI summary

In a vehicle floor frame structure, side members 2 each include a floor side member 21 and a rear side member 22; the floor side member 21 is disposed on a main floor panel 11; the rear side member 22 is disposed on a rear floor panel 12; a reinforcement 3 is stacked on the floor side member 21 in a vertical direction with the main floor panel 11 interposed therebetween; an upper surface 3a of the reinforcement 3 becomes higher toward the rear of the vehicle body; a front portion 3b and lower portions of side surfaces 3c of the reinforcement 3 are joined to the main floor panel 11; a rear end portion 3d of the reinforcement 3 is joined to the vertical wall 13a in a front portion of the rear floor panel 12; a closed section space S1 enclosed by the main floor panel 11, a front portion 13 of the rear floor panel 12, and the reinforcement 3 is formed in a side view; a lower surface portion 21b of a rear end of the floor side member 21 becomes higher toward the main floor panel 11; and the upper surface 3a of the reinforcement 3 and the lower surface portion 21b of the floor side member 21 are inclined at almost the same angles and are formed to have a monotonous cross section in a side view.