Vehicle Door Inner Panel with Integrated Stair Reinforcement

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Solution Overview

Problem

Existing vehicle door inner panels require separate reinforcing members for good collision properties, leading to low production efficiency and high costs.

Innovation Solution

A panel-like formed product with a polygonal top board, vertical walls, and a flange, featuring a concave portion that absorbs collision energy, eliminating the need for additional reinforcing members by integrating the concave portion into the door inner panel structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a soft steel plate with high workability is used to suppress cracks and wrinkles during press working, then manufacturing ease is improved, but the strength of the door inner panel deteriorates

Engineering Contradiction:
Improveworkability during press workingVSAvoidstrength of door inner panel
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention merges the door inner panel with a reinforcing member into a single integrated structure. The reinforcing rib is formed as an integral part of the door inner panel through press working, eliminating the need for separate reinforcing members while providing both formability and strength

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention segments the door inner panel into multiple regions with different thicknesses. By forming reinforcing ribs with increased thickness in specific areas, the panel achieves localized strength enhancement while maintaining overall formability during press working

Inventive Principle:
Principle #1Segmentation

2Strength

If a reinforcing member is attached to the door inner panel to increase strength, then collision properties are improved, but device complexity and production cost increase

Engineering Contradiction:
Improvecollision propertyVSAvoidnumber of components
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The reinforcing member is merged with the door inner panel to form a single integrated component. The reinforcing rib is formed as an integral part of the panel through press working, eliminating the need for separate reinforcing members and reducing assembly complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The door inner panel serves multiple functions: it provides the basic door structure, ensures sealing through its shape, and provides collision resistance through the integrated reinforcing rib. This multi-functionality eliminates the need for separate reinforcing members

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If a reinforcing member is attached to the door inner panel to ensure collision resistance, then safety is improved, but production efficiency deteriorates

Engineering Contradiction:
Improvecollision resistanceVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The door inner panel and reinforcing member are combined into a single integrated component formed in one press working process. This eliminates the need for separate manufacturing and assembly steps, improving production efficiency while maintaining collision resistance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reinforcing rib structure is preliminarily formed during the press working process itself, before the door assembly is completed. This preliminary formation of the reinforcing structure eliminates subsequent assembly steps and improves production efficiency

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3409393B1Panel-shaped molded article used as a door inner panel of a vehicle, vehicle door, and method for manufacturing panel-shaped molded article
Publication Date: 2021.03.17 NIPPON STEEL CORPORATION
  • EP3409393B1 patent drawingFigure 1
  • EP3409393B1 patent drawingFigure 2
  • EP3409393B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a panel-like formed product having an excellent collision property. The panel-like formed product (1) includes a polygonal top board (2), two or more vertical walls (5), and a flange (7). The vertical walls (5) extend from two or more sides of the top board (2), and include at least two adjacent vertical walls (5) extending from at least two adjacent sides of the top board (2). The flange (7) connects to lower ends of the vertical walls (5) and spreads in directions in which the top board (2) spreads. The top board (2) includes a frame portion (3) including the two or more sides of the top board from which the vertical walls extend, and a concave portion (4) which is located at an inner side of the frame portion (3) and recedes from the frame portion (3). The two or more adjacent vertical walls (5) include a first vertical wall section (5A), a stair (6), and a second vertical wall section (5B). The stair (6) connects to a lower end of the first vertical wall section (5A) and spreads in the directions in which the top board spreads. The second vertical wall section (5B) connects to an outer edge of the stair (6) and extends in a direction in which the first vertical wall section (5A) extends. The flange (7) connects to a lower end of the second vertical wall section (5B).