Vehicle Ceiling Assist Grip Groove Design

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Solution Overview

Problem

Conventional vehicle ceiling structures face issues where excessive stress concentrates on the assist grip during curtain shield air bag expansion, and the appearance of the ceiling interior material around the assist grip is compromised due to non-uniform slit expansion and visibility of slits.

Innovation Solution

A vehicle ceiling structure featuring an annular groove on the outer circumference of the attachment portion and coupling grooves that allow the ceiling interior material to bend tubularly, preventing stress concentration and improving appearance by allowing smooth expansion of attachment holes and hiding the grooves from the cabin side.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If slits are formed in the ceiling interior material to allow expansion of attachment holes, then the ceiling interior material can escape from the assist grip during air bag deployment, but excessive stress concentrates on the assist grip when slits do not split uniformly

Engineering Contradiction:

Improveescape function of ceiling interior materialVSAvoidstress concentration on assist grip

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The attachment hole is segmented into multiple regions by forming radial grooves that divide the hole into several sectors. This segmentation allows each sector to expand independently and uniformly during air bag deployment, preventing stress concentration on the assist grip while ensuring reliable escape of the ceiling interior material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The radial grooves are pre-formed in the ceiling interior material before deployment. These grooves prepare the material structure in advance to expand uniformly along predetermined paths when the air bag inflates, eliminating the uncertainty of non-uniform slit splitting and preventing excessive stress on the assist grip.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If long slits are formed to sufficiently increase the diameter of attachment holes, then the ceiling interior material can escape smoothly, but the slits are visible from the vehicle cabin side, degrading the appearance

Engineering Contradiction:

Improvesmooth escape of ceiling interior materialVSAvoidappearance of ceiling interior material

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The grooves are formed on the reverse side of the ceiling interior material, perpendicular to the visible surface. This positional change allows the grooves to perform their functional role in expanding the attachment holes while remaining hidden from view in the vehicle cabin, thus maintaining aesthetic appearance while ensuring smooth escape of the material.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The functional feature (grooves for expansion) is extracted and placed on the reverse side of the visible surface. This separates the functional requirement from the aesthetic requirement, allowing the grooves to be positioned where they can perform their expansion function without being visible from the vehicle cabin side.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If multiple slits are formed around attachment holes to ensure uniform expansion, then stress distribution improves, but the slits remain visible from the vehicle cabin side

Engineering Contradiction:

Improveuniform expansion of attachment holesVSAvoidvisibility of slits from cabin side

Core Design Contradiction:

Stability of the object's compositionVSShape

Solution Approach 1:

The expansion features are relocated from the visible surface to the reverse side of the ceiling interior material. By forming grooves on the opposite side from where they would be visible, the solution maintains uniform expansion stability while eliminating visual defects from the cabin side.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Different surfaces of the ceiling interior material are given different qualities: the vehicle cabin side maintains a smooth, appearance-oriented surface without visible grooves, while the reverse side contains the functional grooves needed for uniform expansion. This local differentiation resolves the contradiction between functional performance and aesthetic appearance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8925960B2Vehicle ceiling structure

Publication Date: 2015.01.06 TOYOTA BOSHOKU KK

AI summary

A vehicle ceiling structure includes a ceiling interior material that covers a curtain shield air bag with a terminal side, an assist grip is attached to a body panel through an attachment hole provided in the ceiling interior material and an attachment portion is provided on the assist grip. The attachment portion is in contact with or faces an outer circumference of the attachment hole in a surface of the ceiling interior material in a vehicle cabin side. The vehicle ceiling structure on a surface thereof in a vehicle cabin outer side, has an annular groove facing the outer circumference of the attachment portion such that the annular groove surrounds the attachment portion.