Rear Body Subframe Connection Layout for Battery Frame Load Transfer
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Solution Overview
Problem
In vehicles with a rear subframe disposed below a side frame, the connecting portion to a battery frame mounted on the outer side in the vehicle width direction is prone to deformation during rear collisions, leading to ineffective load transmission to the battery frame, compromising passenger safety.
Innovation Solution
A vehicle body rear part structure featuring a subframe with a connecting portion that includes an inclined portion extending outwardly in the vehicle width direction and a widening portion, which faces a vertical frame and lateral frame respectively, to enhance load transmission to the battery frame and improve safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connecting portion is disposed on the vehicle body front side extending linearly inclined outwardly in the vehicle width direction, then the battery frame can be connected, but the connecting portion deforms under collision load and load transmission fails
Solution Approach 1:
The connecting portion is designed to extend in multiple directions rather than a single linear path. It has a first direction component extending forwardly and a second direction component extending outwardly in the vehicle width direction, creating a two-dimensional configuration that resists deformation from rearward collision loads while maintaining connection to the battery frame.
Solution Approach 2:
The connecting portion includes an inclined surface that is inclined outwardly in the vehicle width direction as it extends forwardly. This curved/angled geometry distributes collision loads more effectively and prevents the linear deformation that would occur in a straight connecting portion, thereby maintaining structural integrity and load transmission capability.
2Quantity of substance
If a large battery is mounted on the battery frame, then the battery frame must be disposed on the outer side in vehicle width direction, but this increases the distance and complexity of load transmission path
Solution Approach 1:
The connecting portion serves multiple functions simultaneously: it connects the subframe to the battery frame, transmits collision loads from the rear, and accommodates the offset position of the battery frame due to large battery mounting. The multi-directional extension design allows a single connecting structure to handle both longitudinal and lateral load components.
3Ease of operation
If the connecting portion extends linearly inclined outwardly, then it can reach the battery frame on the outer side, but it cannot effectively transmit load due to deformation
Solution Approach 1:
The connecting portion is divided into functional segments: a first direction component for reaching forward to the battery frame position, and a second direction component for extending outwardly to connect to the battery frame on the outer side. This segmentation allows each portion to optimize its geometry for its specific function while working together to maintain load transmission reliability.
Data Source
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AI summary
A vehicle body rear part structure for a vehicle includes a side frame, a subframe disposed below the side frame and extending in a vehicle body front-rear direction, and a vehicle body frame member disposed on a middle side in the vehicle body front-rear direction with respect to the subframe, offset outwardly in a vehicle width direction with respect to the subframe, and extending in the vehicle body front-rear direction. The vehicle body frame member includes: a vertical frame offset outwardly in the vehicle width direction with respect to the subframe, and extending in the vehicle body front-rear direction; and a lateral frame extending inwardly in the vehicle width direction from the vertical frame. A connecting portion connected to the vehicle body frame member is provided on the subframe. The connecting portion includes: an inclined portion extending while being inclined outwardly in the vehicle width direction, as extending toward a middle portion in the vehicle body front-rear direction, to face the vertical frame; and a widening portion widening inwardly in the vehicle width direction up to a position where the connecting portion linearly extends in the vehicle body front-rear direction from the inclined portion, to face the lateral frame.