Vehicle Lower Frame Triangulation for Side Sill Load Transfer

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Solution Overview

Problem

Existing vehicle designs struggle to effectively transmit side collision loads to the opposite side sill in the vehicle width direction, leading to potential deformation or breakage of the floor section during side collisions.

Innovation Solution

A vehicle lower structure featuring paired side sills and a frame member with triangular structure portions that extend in the front-rear direction, distributing and transmitting collision loads via integrated beam structures to the opposite side sill, enhancing load-bearing capacity and rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single first cross member and a single second cross member are used on each side of the floor tunnel, then the structure is simple, but the side collision load cannot be effectively transmitted to the opposite side sill

Engineering Contradiction:
Improveside collision load transmissionVSAvoidframe member structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The frame member is divided into multiple beam structure portions (first oblique beam portions and second oblique beam portions) that form multiple triangular structure portions. This segmentation allows the side collision load to be distributed across multiple load paths, enabling effective transmission to the opposite side sill while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a multi-dimensional load transmission path by creating triangular structure portions that extend in the front-rear direction. This adds a new dimension to the load transmission mechanism, allowing forces to be distributed not only laterally but also longitudinally across the floor section.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If multiple beam structure portions are combined to form triangular structure portions, then load distribution improves, but manufacturing complexity increases

Engineering Contradiction:
Improveload-bearing capacityVSAvoidframe member fabrication
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Multiple beam structure portions are merged to form integrated triangular structure portions within a single frame member. This combining approach enhances load-bearing capacity through geometric stability while reducing the number of separate components, thereby simplifying manufacturing compared to using multiple discrete members.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the frame member has plural triangular structure portions continuing in the front-rear direction, then side collision load can be transmitted to the opposite side sill, but the structure becomes more complex

Engineering Contradiction:
Improvefloor section protectionVSAvoidframe member configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The continuous front-rear extension of triangular structure portions is achieved through segmentation into multiple beam structure portions that are systematically arranged and connected. This segmentation creates a progressive load transmission path that protects the floor section while maintaining a manageable structural configuration.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4650250A1Vehicle lower structure
Publication Date: 2025.11.19 MAZDA MOTOR CORP
  • EP4650250A1 patent drawingFigure 1~2
  • EP4650250A1 patent drawingFigure 3~4
  • EP4650250A1 patent drawingFigure 5~6

AI summary

A frame member 11 has paired side beam portions 110 and an inner frame portion 111. The inner frame portion 111 has: plural first oblique beam portions 114, each of which is formed to extend forward to an outer side in a vehicle width direction from an inner side in the vehicle width direction; and plural second oblique beam portions 115, each of which is formed to extend rearward to the outer side in the vehicle width direction from the inner side in the vehicle width direction. The frame member 11 has plural triangular structure portions AR1, each of which is formed by the respective side beam portion 110 and an adjacent pair of the first oblique beam portion 114 and the second oblique beam portion 115 in a front-rear direction, and which continue in the front-rear direction on both sides in the vehicle width direction.