Vehicle Frame Side Rail Stiffness Segmentation
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Solution Overview
Problem
Existing vehicle body frame structures face challenges in simultaneously suppressing the movement of the front tire towards the cabin during an offset collision while maintaining the absorption of collision energy during a front collision, as they either allow excessive tire movement or reduce energy absorption.
Innovation Solution
A vehicle body frame structure featuring a side rail with a projecting portion and a cab mount member that restricts tire movement during offset collisions and allows deformation for energy absorption during front collisions, utilizing curved and inclined surfaces to manage collision loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If members are provided at the side rails to make it difficult for the side rails to deform at the time of a front collision, then movement of the front tire toward the vehicle cabin side is suppressed at the time of an offset collision, but the absorbed amount of collision energy decreases because it is difficult for the side rails to deform at the time of a front collision
Solution Approach 1:
The side rail is divided into multiple regions with different functional characteristics: a first region (front portion) designed to deform easily for energy absorption during front collisions, and a second region (rear portion) with enhanced stiffness to suppress tire movement during offset collisions. This segmentation allows each region to perform its specific function independently, resolving the contradiction between energy absorption and tire movement suppression.
Solution Approach 2:
Different portions of the side rail are given different local qualities: the front portion has lower stiffness to facilitate energy absorption through deformation, while the rear portion has higher stiffness to prevent tire intrusion into the cabin during offset collisions. This local differentiation of mechanical properties enables the side rail to simultaneously satisfy both contradictory requirements in different spatial locations.
2Loss of energy
If the side rails are structured to deform easily at the time of a front collision, then collision energy is absorbed effectively, but at the time of an offset collision, the side rail deforms more than needed and the front tire may move toward the vehicle cabin side
Solution Approach 1:
The side rail is segmented into a first region optimized for energy absorption and a second region optimized for structural support. The first region deforms easily during front collisions to absorb energy, while the second region maintains sufficient stiffness to prevent tire movement into the cabin during offset collisions, thus resolving the contradiction through functional segmentation.
Solution Approach 2:
The side rail exhibits different local mechanical qualities along its length: the front portion is designed with lower stiffness to enable energy absorption through controlled deformation, while the rear portion is designed with higher stiffness to maintain structural integrity and prevent cabin intrusion during offset collisions.
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
The structure effectively suppresses front tire movement towards the cabin during offset collisions and maintains collision energy absorption during front collisions, enhancing safety by balancing these two critical factors.
Implementation Method 1
collision energy is absorbed by the side rails deforming
Implementation Method 2
the front tire contacts the projecting portion. Due thereto, movement of the front tire toward the vehicle cabin side is restricted
Implementation Method 3
the collision load that is inputted from the front tire to the projecting portion is transmitted through the cab mount member to the side rail
Data Source
AI summary
The present disclosure provides a vehicle body frame structure including: a side rail extending in a vehicle longitudinal direction and disposed so as to face a front tire in a vehicle transverse direction; a cab mount member projecting toward a vehicle transverse direction outer side, from a region of the side rail that is further toward a vehicle rear side than the front tire, and to which a body is mounted; and a projecting portion projecting toward the front tire from a region of the cab mount member that is away from the side rail in the vehicle transverse direction.