Shoe Sole with Viscoelastic Heel Absorber for Weight Reduction

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Solution Overview

Problem

Existing shoe soles struggle to balance shock absorbing performance, stability, durability, and weight reduction, with existing designs either compromising on one or more of these factors.

Innovation Solution

A sole design featuring a midsole, outsole, medial and lateral highly rigid members, and a shock absorber positioned to overlap or surround the heel center, with a pocket-shaped space allowing for deformation and weight reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the shock absorber is disposed along the peripheral edge of the rearfoot portion, then weight reduction is achieved, but shock absorbing performance at the heel center is insufficient

Engineering Contradiction:

ImproveweightVSAvoidshock absorbing performance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The shock absorber is positioned specifically at the heel center region rather than uniformly distributed, concentrating shock absorption functionality where it is most needed during heel strike, while maintaining weight reduction through selective placement

Inventive Principle:

Principle #3Local quality

2Reliability

If the shock absorber reaches the heel center, then shock absorbing performance is improved, but weight reduction and stability are inhibited

Engineering Contradiction:

Improveshock absorbing performanceVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The shock absorber is concentrated at the heel center region rather than uniformly distributed throughout the rearfoot, providing targeted shock absorption where it is most needed during heel strike while minimizing overall material usage and weight

Inventive Principle:

Principle #3Local quality

3Stability of the object's composition

If a less-deformable portion is disposed on the bottom surface of the midsole, then stability is improved, but shock absorbing performance is insufficient

Engineering Contradiction:

ImprovestabilityVSAvoidshock absorbing performance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The rearfoot structure is segmented into distinct functional zones: a less-deformable portion for stability and a deformable shock absorber region for impact absorption, allowing each component to perform its specialized function without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the sole are assigned different mechanical properties - the less-deformable portion provides structural stability while the shock absorber region provides impact attenuation, with each zone optimized for its specific function

Inventive Principle:

Principle #3Local quality

4Strength

If members contact one another under vertical compressive load, then stiffness is increased, but shock absorbing performance is reduced due to insufficient deformation space

Engineering Contradiction:

ImprovestiffnessVSAvoidshock absorbing performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The structure is divided into a less-deformable portion that maintains stability and a separate shock absorber portion that is allowed to deform, preventing unwanted contact and stiffness in the shock absorption region while maintaining overall structural integrity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The less-deformable portion acts as an intermediary structure that supports the shock absorber, allowing it to deform freely for shock absorption while the less-deformable portion maintains structural stability and prevents excessive deformation

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The design achieves enhanced shock absorbing performance, stability, and durability while reducing weight by using a viscoelastic shock absorber surrounded by a pocket-shaped space and highly rigid members.

Implementation Method 1

a shock absorber formed of a solid viscoelastic body, the shock absorber being sandwiched in the up-down direction by the midsole and the outsole

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP4437897B1Sole and shoe including the same

Publication Date: 2025.10.15 ASICS CORP

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AI summary

A sole (10) includes a midsole (20) and an outsole (30B). A portion of a rearfoot portion that includes a heel center (HC) is provided with a facing region in which the midsole (20) and the outsole (30B) face each other at a distance from each other in an up-down direction, and the facing region is provided with a shock absorber (50). The midsole (20) is made of a foam material. The shock absorber (50) is formed of a solid viscoelastic body and disposed to overlap or surround the heel center (HC). A medial foot-side highly rigid member (40A) and a lateral foot-side highly rigid member (40B) are disposed at a medial foot-side end portion and a lateral foot-side end portion, respectively, in portions of the rearfoot portion that correspond to the facing region, so that the facing region is provided with a pocket-shaped space that surrounds the shock absorber (50).