Vehicle Subframe Displacement Portion for Collision Load Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In vehicle rear suspension systems, increasing the strength of side members to handle longitudinal loads can hinder the proper transmission and absorption of collision loads during rear collisions, as the arm members may not move appropriately to absorb the impact.
Innovation Solution
A sub frame structure with a pair of right-and-left side members and a rear cross member, where the side members have arm connection portions arranged along the vehicle longitudinal direction, with a displacement portion between the front and rear arm connection portions, allowing the rear arm connection portion to displace forward and rotate, preventing the arm member from hindering collision load absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the strength of the side member is increased to handle longitudinal loads, then the longitudinal load transmission capability is improved, but the arm member cannot move properly during rear collision, hindering collision load absorption
Solution Approach 1:
The side member is divided into multiple sections with different properties: a first section with higher strength for longitudinal load transmission, and a second section with lower strength that allows deformation during rear collision. This segmentation enables the structure to provide both strength and controlled flexibility for different functional requirements.
Solution Approach 2:
Different portions of the side member are assigned different mechanical properties. The first section (front portion) has higher strength to transmit longitudinal loads from the arm member, while the second section (rear portion) has lower strength to deform and absorb collision energy, allowing the arm member to move appropriately during rear collisions.
2Strength
If the side member is made stronger to transmit longitudinal load, then longitudinal load transmission is improved, but the vehicle body cannot properly absorb collision load during rear collision
Solution Approach 1:
The side member is segmented into a first section for longitudinal load transmission and a second section for collision energy absorption. This allows the structure to reliably perform both functions: transmitting suspension loads and absorbing collision loads through controlled deformation.
Solution Approach 2:
The weaker second section of the side member is designed to deform intentionally during rear collisions, converting the harmful collision energy into beneficial energy absorption that protects the vehicle body and occupants, while the stronger first section maintains structural integrity for load transmission.
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 sub frame structure ensures proper transmission and absorption of collision loads by allowing the arm member to displace and rotate, while still transmitting longitudinal loads effectively, even with increased side member strength.
Implementation Method 1
a displacement portion to cause the rear arm connection portion to be displaced forward is provided between the front arm connection portion and the rear arm connection portion
Data Source
AI summary
A sub frame structure of a vehicle comprises a pair of right-and-left side members extending in a vehicle longitudinal direction, to which a pair of right-and-left upper-side lower arm supporting rear wheels are pivotally connected, a rear cross member holding the vicinity of rear ends of the side members, and a front cross member interconnecting the side members in a vehicle width direction and being positioned in front of the rear cross member, being spaced apart from the rear cross member. The side member includes a front support bracket and a rear member holding member to which a front connection portion and a rear connection portion of the upper-side lower arm are connected, and a displacement portion to cause the rear member holding member to be displaced forward is provided between the front support bracket and the rear member holding member.