Vehicle Front Body Subframe Shock Absorption Design
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Solution Overview
Problem
Existing vehicle front body designs struggle to effectively absorb large shocks due to the limited strength of suspension members, which prevents the transmission of significant loads to the vehicle body, leading to inadequate shock absorption and potential deformation of the front wall.
Innovation Solution
The design incorporates a subframe with front and rear arm connecting parts, an engine contact part, and rear fastening parts that distribute loads radially, canceling turning forces and allowing the subframe to deform and absorb shocks by bending and shearing bolts, while preventing front wall deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the suspension member is configured to be deformed and bent to absorb shocks, then the suspension member can provide some shock absorption, but the strength of the suspension member becomes small and cannot transmit large shocks to the vehicle body
Solution Approach 1:
The subframe is divided into multiple members (front left member, front right member, rear left member, rear right member) that are selectively deformable. This segmentation allows specific members to absorb shocks through deformation while other members maintain structural strength for load transmission, resolving the contradiction between shock absorption and strength.
Solution Approach 2:
Different regions of the subframe are designed with different properties: the front members are designed to be deformable for shock absorption, while the rear members and connecting structures are designed with higher strength for load transmission. This local differentiation allows simultaneous achievement of shock absorption and strength requirements.
2Loss of energy
If the rear fastening part is turned about the bolt axis to absorb shock, then the shock can be absorbed, but the turning forces are not cancelled and the bolt cannot generate reactive force continuously
Solution Approach 1:
The subframe employs asymmetric deformation patterns where the left and right members deform in opposite directions. This asymmetry causes the turning forces on the rear fastening parts to cancel each other out, preventing rotation about the bolt axis and allowing continuous reactive force generation while maintaining shock absorption.
3Loss of energy
If the subframe is designed to retract to absorb shock, then shock absorption is improved, but the front wall may be deformed or pushed into the cabin
Solution Approach 1:
The subframe is designed with predetermined deformation paths and controlled collapse mechanisms that allow it to retract and absorb shock in a controlled manner. This preliminary design ensures that the retraction occurs without pushing the front wall into the cabin, preventing harmful effects while maintaining shock absorption capability.
Data Source
AI summary
A front body of a vehicle includes left and right front side frames and a subframe attached to the front side frames. The subframe includes front arm connecting parts and rear arm connecting parts configured to support lower arms of respective suspensions at left and right ends of the subframe, an engine contact part disposed in an upper part of the subframe and facing toward an engine, and rear fastening parts each disposed in a continuous part between the engine contact part and the corresponding rear arm connecting part and fastened to the corresponding front side frame. The rear fastening parts each are formed in a branch part disposed between the corresponding rear arm connecting part and the engine contact part and protruding from a rear branch member toward the rear of the vehicle.