Rear Vehicle Body Structure With Box Sections for Torsional Rigidity

The rear pillar assembly is divided into multiple components: rear pillar inner upper member, rear pillar inner lower member, transverse extension member, wheel house inner extension member, and integrated extension member. This segmentation allows each component to be optimized for specific functions while distributing the load-bearing responsibilities across multiple connection points, thereby maintaining joint strength despite increased overall load capacity.

The patent introduces three-dimensional box closed sections formed by the interconnected members. These box structures add spatial dimensionality to the load distribution, creating rigid geometric shapes that resist deformation from multiple directions. The box closed sections transform the load-bearing system from simple linear connections to volumetric structures, significantly improving both load capacity and joint strength simultaneously.

The box closed sections created by the interconnected members form three-dimensional rigid structures that provide excellent torsional resistance. The volumetric geometry of these boxes creates multiple load paths and increases the moment of inertia, thereby improving torsional performance while maintaining the ability to support high vertical loads from battery assemblies.

The patent employs a composite structure combining multiple metal members with different geometric configurations. The rear pillar inner members, extension members, and box closed sections work together as a composite system, where each component contributes specific mechanical properties. This composite approach allows optimization for both load support and torsional rigidity that cannot be achieved with a single uniform structure.

The integrated extension member combines multiple extension functions into a single component that connects the rear pillar inner lower member to both the transverse extension member and the wheel house inner extension member. This merging reduces the total number of separate parts and connections needed, simplifying the overall structure while maintaining multiple connection points for enhanced joint strength.

Each member in the assembly serves multiple functions: the rear pillar inner lower member provides both structural support and connection points; the extension members simultaneously extend the structure and create box closed sections; the integrated extension member connects multiple components while forming part of the box structure. This multi-functionality reduces the number of dedicated components needed, lowering complexity while maintaining joint strength.