Soft polyurethane foam molded article and seat pad

Solution Overview

Problem

Soft polyurethane foam molded articles, such as seat pads, experience trembling issues under centrifugal forces, which can impair cushioning properties when attempts to increase viscoelasticity are made.

Innovation Solution

The foam is designed with a specific aspect ratio of foaming cells, where the diameter in the horizontal direction increases towards the mounting surface, maintaining a favorable seating feel while enhancing stability by controlling the shape and size of foaming cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the viscoelasticity of soft polyurethane foam is increased to prevent trembling, then stability is improved, but the cushioning property is impaired

Engineering Contradiction:

ImprovestabilityVSAvoidcushioning property

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The patent applies local quality by creating different cell aspect ratios in different regions of the foam. The mounting surface side has cells with larger aspect ratios (more spherical) for stability, while the rear surface side has cells with smaller aspect ratios (more elongated) for cushioning. This spatial differentiation resolves the contradiction by providing different local properties where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a new dimension - the aspect ratio of foaming cells - to control both stability and cushioning properties. By adjusting the ratio of horizontal diameter to vertical diameter of cells, the patent creates a gradient structure that simultaneously achieves trembling prevention and cushioning without increasing overall viscoelasticity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If foam with high hardness and foam with low hardness are mixed to create continuous hardness gradient, then cushioning property is improved, but stability under centrifugal force deteriorates

Engineering Contradiction:

Improvecushioning propertyVSAvoidstability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating different cell aspect ratios in different regions of the foam. The mounting surface side has cells with larger aspect ratios (more spherical) for stability, while the rear surface side has cells with smaller aspect ratios (more elongated) for cushioning. This spatial differentiation resolves the contradiction by providing different local properties where needed.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design effectively prevents trembling while maintaining a comfortable seating experience by adjusting the stiffness distribution and cell shape, ensuring appropriate repulsive forces and reduced oppressive forces.

Implementation Method 1

can be obtained by foaming and molding a raw foaming liquid

Methodology Applied

Scientific EffectFoaming: Foam

Data Source

PatentUS10870377B2Soft polyurethane foam molded article and seat pad

Publication Date: 2020.12.22 ARCHEM INC

AI summary

The present invention provides a soft polyurethane foam molded atticle which has a mounting surface (1A) can be obtained by foaming and molding a raw foaming liquid, and has a constitution which a ratio of a diameter of a foaming cell in the horizontal direction X along the mounting surface (1A) to a diameter of the foaming cell in the vertical direction Y orthogonal to the mounting surface (1A) increases toward the mounting surface (1A) in the vertical direction (Y).