Multi-Shell Shear Panel for Vehicle Underbody Rigidity

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Solution Overview

Problem

Existing shear panels in two-track vehicles lack sufficient rigidity and are heavy due to the need for increased wall thickness to achieve equivalent stiffness, and they require multiple parts and complex assembly, which increases costs and weight.

Innovation Solution

A shear panel designed as a coherent sheet metal part with support arms and additional sheet metal sections forming a multi-shell structure, supported on side sills and axle carriers, providing increased rigidity and reduced weight by forming a shell profile and integrating additional stiffening elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the wall thickness of the shear panel is increased to achieve equivalent rigidity, then the structural rigidity is improved, but the weight increases significantly

Engineering Contradiction:
Improvestructural rigidityVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent transitions from a single-layer sheet metal structure to a multi-shell three-dimensional structure. By adding multiple shells that form a box-like configuration, the structure gains rigidity in the longitudinal direction without increasing the wall thickness of individual sheets. This dimensional transformation allows achieving equivalent stiffness with significantly reduced material usage and weight compared to a thick single-layer panel.

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

Solution Approach 2:

The invention employs a composite structure consisting of multiple sheet metal shells bonded together to form a multi-shell construction. This composite approach combines multiple thinner sheets into a unified rigid structure, achieving the mechanical properties of a thick panel while maintaining the weight advantages of thin-gauge materials. The bonded multi-shell configuration creates a lightweight yet stiff assembly.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If a single-sheet design is used for the shear panel, then the manufacturing simplicity is improved, but the formability and rigidity are limited

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidrigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The shear panel is divided into multiple separate shell components that are subsequently bonded together. This segmentation allows each individual shell to be manufactured using standard stamping processes with conventional tooling, avoiding the need for complex single-piece forming operations. The modular approach enables production of curved and complex geometries that would be difficult or impossible to achieve in a single-sheet design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple individually manufactured shells are combined through bonding processes to form the complete shear panel assembly. This merging of separate components creates a unified rigid structure with enhanced formability and structural performance. The bonding process integrates the segmented parts into a cohesive unit that achieves the desired rigidity while maintaining manufacturing simplicity.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If multiple separate profiles are used to reinforce the shear panel, then the rigidity is improved, but the assembly complexity and costs increase

Engineering Contradiction:
ImproverigidityVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The reinforcement elements are integrated directly into the shell structures themselves rather than being separate attachable components. The shells are formed with built-in reinforcing features during the stamping process, eliminating the need for additional separate profiles and their associated fastening operations. This integration reduces assembly steps and lowers manufacturing costs while maintaining the necessary rigidity.

Inventive Principle:
Principle #5Merging (Combining)

4Object-affected harmful factors

If the shear panel is designed with extended coverage area, then the aerodynamic behavior is improved, but the manufacturing formability is limited

Engineering Contradiction:
Improveaerodynamic behaviorVSAvoidformability
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The extended coverage area is achieved through a multi-shell three-dimensional configuration rather than a single large flat sheet. This dimensional approach allows the structure to span larger areas and conform to complex vehicle underbody geometries by stacking and bonding multiple shells at different orientations and positions, overcoming the formability limitations of single-sheet designs.

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

Data Source

PatentEP3114011B1Stiffening structure of a vehicle in the form of a shear field
Publication Date: 2018.04.11 BAYERISCHE MOTOREN WERKE AG
  • EP3114011B1 patent drawingFigure 1
  • EP3114011B1 patent drawingFigure 2a
  • EP3114011B1 patent drawingFigure 2b

AI summary

The invention relates to a stiffening structure of a two-track vehicle in the form of a shear field (2) designed as a shaped sheet-metal piece, which shear field is fastened to a sub-frame (1) acting as an axle support (1) and optionally to longitudinal members (32l, 32r) of the vehicle and furthermore is supported on lateral door sills (31l, 31r) of the vehicle body, wherein said support is provided by means of supporting arms (21l, 21r) formed in the shaped sheet-metal piece. The supporting arms or further segments of the shear field can be stiffened by means of auxiliary sheets in such a way that there is a shell profile formed by a top shell and a bottom shell as viewed in the direction of the vehicle vertical axis.