Door Panel Waist Reinforcement Segmentation for Weather Strip Molding

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Solution Overview

Problem

Conventional door panel structures for automobiles require a molding die with a narrow die head to form weather strips, leading to durability issues and increased production costs due to the need to reduce the opening width of the weather strip to fit the thin waist flange, which decreases work efficiency.

Innovation Solution

A door panel structure with upper end portions of the door panel and reinforcement connected at multiple points along the fore-and-aft direction, spaced at least one point, and featuring inner and outer reinforcement panels connected by spot welding, allowing the weather strip to be formed with an increased opening width that matches the spaced portions, eliminating the need for a narrow molding die and reducing production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the opening width of the weather strip is increased to improve molding die durability and production efficiency, then the weather strip cannot fit the thin waist flange, but if the opening width is reduced to fit the flange, then molding die durability deteriorates and production cost increases

Engineering Contradiction:
Improvemolding die durabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The reinforcement is divided into inner and outer reinforcement panels that are connected at specific portions, creating a segmented structure. This segmentation allows the reinforcement to provide structural support while maintaining spaced relationships at critical locations, enabling the weather strip to have a wider opening during molding without compromising the overall fit to the waist flange assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from considering only the one-dimensional thickness of the waist flange to a three-dimensional approach by spacing the inner and outer reinforcement panels apart from each other. This creates a volumetric structure where the weather strip can be molded with a larger opening width while still fitting within the overall dimensional envelope of the reinforced door panel assembly.

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

2Manufacturing precision

If the weather strip opening width is reduced after forming to adapt to the thin waist flange, then fitting accuracy is maintained, but work efficiency deteriorates and production cost increases

Engineering Contradiction:
Improvefitting accuracyVSAvoidwork efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The inner and outer reinforcement panels are connected and positioned in advance during the molding process, creating the spaced structure beforehand. This preliminary action eliminates the need for subsequent operations to reduce the weather strip opening width, as the weather strip can be molded with the appropriate opening width from the start and will fit the pre-positioned reinforcement structure.

Inventive Principle:
Principle #10Preliminary action

3Shape

If the door panel and reinforcement are joined in intimate contact to reduce thickness, then structural compactness is achieved, but the weather strip opening width becomes too narrow for efficient molding

Engineering Contradiction:
ImprovethicknessVSAvoidmolding die durability
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The reinforcement structure is segmented into inner and outer panels that are connected at specific portions rather than being in continuous intimate contact. This segmentation creates spaced relationships at critical locations where the weather strip needs to fit, allowing the weather strip to be molded with a wider opening while maintaining overall structural compactness through the connected portions.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP1911619B1Door panel structure and method of producing the same
Publication Date: 2011.04.13 NISSAN MOTOR CO LTD
  • EP1911619B1 patent drawingFigure 1
  • EP1911619B1 patent drawingFigure 2
  • EP1911619B1 patent drawingFigure 3A~3C

AI summary

A door panel structure including a door panel and a door waist reinforcement connected to the door panel. The door waist reinforcement includes an inner reinforcement and an outer reinforcement. The door panel and the door waist reinforcement have respective upper end portions which form a waist flange to which a weather strip is fitted. The waist flange includes a plurality of connecting portions at which the upper end portion of the door panel and the upper end portion of the door waist reinforcement are connected to each other, and at least one spaced portion at which the upper end portion of the door panel and the upper end portion of the door waist reinforcement are spaced from each other.