Corrugated Metal Plate Structure With Balanced Flexural Rigidity

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Solution Overview

Problem

Existing corrugated metal plates used for heat insulation in automobiles have high production costs due to complex press working operations, stress concentration issues, and directional properties that affect usability and strength, leading to potential liquid pooling and secondary defects.

Innovation Solution

A corrugated metal plate design with alternating projection and recess rows forming a wave shape in both directions, minimizing flexural rigidity differences and allowing for single-step pressing, reducing production costs and enhancing usability and strength by eliminating directional properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the recess portion is designed with a bottom side wider than the open side (hooking shape), then elastic property is improved, but press working complexity increases and stress concentration occurs

Engineering Contradiction:
Improveelastic propertyVSAvoidpress working complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent inverts the conventional recess portion design by making the open side wider than the bottom side, opposite to the traditional hooking shape. This inversion eliminates the need for complex multi-step pressing operations while preventing stress concentration, thereby resolving the contradiction between elastic property improvement and press working complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Strength

If both cross-sectional shapes are corrugated, then surface rigidity is improved, but directional property increases causing strength difference between directions

Engineering Contradiction:
Improvesurface rigidityVSAvoidusability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent introduces asymmetry in the corrugation design by making the cross-sectional shape in one direction different from the other direction. Specifically, one direction has a corrugated shape while the other has a different corrugation pattern, which balances the flexural rigidity in both directions and eliminates directional property, thereby improving usability without sacrificing surface rigidity.

Inventive Principle:
Principle #4Asymmetry

3Strength

If the recess portion has an inverse shape, then elastic property is improved, but stress concentration occurs during repeated vibration

Engineering Contradiction:
Improveelastic propertyVSAvoidstress resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent inverts the recess portion shape design by making the open side wider than the bottom side, opposite to the conventional inverse shape. This design change maintains elastic property while eliminating stress concentration points that would occur during repeated vibration, thereby improving reliability without sacrificing elastic performance.

Inventive Principle:
Principle #13The other way round (Inversion)

4Strength

If the recess portion is designed with wide bottom, then elastic property is improved, but liquid pooling occurs when formed into three-dimensional shape

Engineering Contradiction:
Improveelastic propertyVSAvoidliquid pooling
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the recess portion geometry by making the open side wider than the bottom side, opposite to the conventional wide-bottom design. This inversion prevents liquid from pooling in the recess portions when the metal plate is formed into three-dimensional shapes like heat insulation covers, while maintaining the elastic property through the corrugated structure.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3330507B1Metal plate
Publication Date: 2021.08.11 NISSAN MOTOR CO LTD
  • EP3330507B1 patent drawingFigure 1
  • EP3330507B1 patent drawingFigure 2
  • EP3330507B1 patent drawingFigure 3(A)~3(C)

AI summary

Projection row (2) and recess row (3) are alternately and successively formed in a direction (Y-direction) perpendicular to a direction (X-direction) of their rows, thereby forming a corrugated cross-sectional shape of a cross-sectional wave shape. Between projection row (2) and recess row (3), there is provided inclined wall surface (4) having a wave shape in plan view. Each of projection row (2) and recess row (3) has a shape in a cross-section along X-direction that is formed into a corrugated cross-sectional shape of a wave shape. Pitch and height difference between valley portion (5) and crest portion (6) in the corrugated cross-sectional shape along this X-direction are smaller, as compared with a relationship between projection row (2) and recess row (3) in the corrugated cross-sectional shape along Y-direction. The corrugated metal plate of such shape has advantages that machining for making cross-sectional shapes in two directions of X and Y into wave shapes is easy and that the flexural rigidity difference between two direction of X and Y is extremely small.