Plastic Tailgate Joining Structure for Stiffness and Crash Energy Absorption

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Solution Overview

Problem

The existing automobile tailgate structures face issues with reduced denting stiffness and modal behavior due to large gaps between inner and outer panels, leading to surface quality defects and inadequate energy absorption in high-speed collisions.

Innovation Solution

A plastic tailgate structure with a joining member comprising L-shaped first and second joining plates, reinforced ribs, and thin or cut-open weak areas, which are easier to break during collisions, enhancing denting stiffness and energy absorption while minimizing surface defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional joining walls are formed by making the inner panel protrude inwardly, then joining strength between inner and outer panels is improved, but surface quality of the inner panel deteriorates with concave defects and shrinkage marks

Engineering Contradiction:
Improvejoining strengthVSAvoidsurface quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A separate joining member is introduced as an intermediary component between the inner panel and outer panel. This joining member includes a first joining plate connected to the inner panel and a second joining plate connected to the outer panel, forming an L-shaped structure. This mediator provides the necessary joining function without requiring the inner panel itself to form protruding walls, thereby maintaining surface quality while achieving strong panel connection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If joining walls are made thick to improve structural strength, then joining strength is improved, but energy absorption capability deteriorates in high speed collisions

Engineering Contradiction:
Improvejoining strengthVSAvoidenergy absorption
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The joining member exhibits non-uniform thickness distribution with different regions having different mechanical properties. The first and second joining plates have different thicknesses, and reinforcing ribs are strategically placed to provide local strengthening where needed while maintaining thinner sections in areas requiring energy absorption. This local quality variation enables the structure to simultaneously achieve adequate joining strength and controlled energy absorption during collisions.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the cavity area distance between outer and inner panels is increased for structural reasons, then structural design flexibility is improved, but denting stiffness deteriorates

Engineering Contradiction:
Improvestructural design flexibilityVSAvoiddenting stiffness
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The joining member extends in multiple spatial dimensions with the first joining plate connected to the inner panel and the second joining plate connected to the outer panel, forming an L-shaped three-dimensional structure. Reinforcing ribs are arranged in specific spatial patterns to provide structural support. This multi-dimensional configuration effectively bridges the large cavity distance, maintaining denting stiffness despite increased panel separation for structural design flexibility.

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

Data Source

PatentEP3950394B1Plastic tailgate structure and automobile
Publication Date: 2023.10.18 YANFENG PLASTIC OMNIUM AUTOMOTIVE EXTERIOR SYST CO LTD
  • EP3950394B1 patent drawingFigure 1
  • EP3950394B1 patent drawingFigure 2
  • EP3950394B1 patent drawingFigure 3

AI summary

The invention relates to plastic tailgate structure for automobile, comprising an inner panel (2) and a cover part (1) of the tailgate which are joined with each other, characterized in that on a surface of the inner panel (2) is provided a joining member (4) comprising a first joining plate (41) connected with the inner panel (2) and a second joining plate (42) joined with the cover part (1) of the tailgate, and in that the first joining plate (41) is integrally formed with the second joining plate (42) in a general L-shape with an almost right angle between them. The invention further relates to an automobile, comprising the above-mentioned plastic tailgate structure.