Rear Vehicle Sub-Frame U-Shaped Side Member Load Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rear vehicle body structures face challenges in securing sufficient rigidity of the sub-frame and efficiently dispersing loads from rear suspensions to rear side frames and cross members, due to deformation of cross members leading to positional displacement of the sub-frame's mounting portion.
Innovation Solution
The design incorporates left and right rear side frames with front and rear cross members spanning between them, a sub-frame with U-shaped sub side members, and extension portions connecting to joint sections between the cross members and side frames, forming a compact rectangular framework to enhance rigidity and load dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mounting portion of the sub-frame is bolted to the cross member via extension members, then the sub-frame can be connected to the rear side frames and cross members, but the mounting portion may be positionally displaced when the cross members deform to curve
Solution Approach 1:
The sub-frame is divided into multiple components: left and right sub side members with U-shaped cross-sections, front and rear sub cross members, and extension members. This segmentation allows each component to independently manage specific loads and deformations, preventing positional displacement of the mounting portion while maintaining connection strength.
Solution Approach 2:
The sub side members are designed with U-shaped cross-sections that provide different structural properties at different locations. The flanges of the U-shape engage with the extension members to prevent lateral displacement, while the web provides vertical load-bearing capacity. This local quality differentiation ensures positional stability during cross member deformation.
2Ease of operation
If the sub-frame is designed with a larger size to accommodate mounting portions, then the mounting can be secured, but the rigidity of the sub-frame is insufficient
Solution Approach 1:
The sub side members utilize U-shaped cross-sections that extend in multiple dimensions. The flanges project laterally to engage with extension members, while the web extends vertically to bear loads. This multi-dimensional geometry achieves both mounting capability and rigidity without increasing the overall footprint of the sub-frame.
Solution Approach 2:
The sub-frame employs composite construction combining the U-shaped sub side members with front and rear sub cross members to form a rigid rectangular framework. This composite structure distributes loads efficiently across multiple members, enhancing rigidity while maintaining compact dimensions suitable for mounting operations.
3Ease of operation
If the distance between the left and right sub side members is increased to facilitate mounting, then the mounting portion can be accessed, but the rigidity of the framework is reduced
Solution Approach 1:
The sub side members feature U-shaped cross-sections with curved flanges that wrap around the extension members. This curved geometry provides multiple contact points and engagement zones, maintaining framework rigidity while allowing sufficient space for mounting operations. The curvature distributes stresses more effectively than straight geometries.
Data Source
AI summary
Rear vehicle body structure (10) includes a sub-frame (16), which has left and right sub side members (51, 52) and front and rear sub cross members (53, 54) that together constitute a substantially rectangular framework (46). The left sub side member includes a left rear extension portion (58) extending from the framework toward the rear of the vehicle body and connected to a left rear joint section (42), where the rear cross member and the left rear side frame are joined together. The right sub side member includes a right rear extension portion (63) extending from the framework toward the rear of the vehicle body and connected to a right rear joint section (44).