Footwear Sole Phase Change Material Thermal Management

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Solution Overview

Problem

Traditional footwear soles do not effectively manage thermal transfer from hot ground surfaces, leading to discomfort and fatigue due to inadequate accommodation of environmental factors such as heated asphalt or artificial grass.

Innovation Solution

A sole structure incorporating a fluid-filled chamber with a phase change material and an insulating member, where the phase change material transitions between solid and liquid states to absorb and release thermal energy, maintaining foot temperature within a comfortable range and minimizing thermal transfer from the ground.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If traditional midsole materials are used, then cushioning is provided, but thermal management capability is insufficient

Engineering Contradiction:
Improvefoot temperatureVSAvoidthermal management reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent incorporates a phase change material within the midsole structure that transitions between solid and liquid states to absorb and release thermal energy. This phase transition mechanism actively regulates foot temperature by absorbing excess heat when the foot becomes hot and releasing it when the foot cools, providing dynamic thermal management that traditional static foam materials cannot achieve.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention combines traditional polymer foam materials with phase change materials to create a composite midsole structure. This composite approach integrates the cushioning properties of foam with the thermal regulation capabilities of phase change materials, simultaneously addressing both comfort and temperature control requirements that neither material could achieve alone.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If polymer foam materials are used for cushioning, then comfort is improved, but adaptability to environmental temperature factors is insufficient

Engineering Contradiction:
Improveenvironmental adaptationVSAvoidsole structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The phase change material automatically adapts to environmental temperature changes through its phase transition properties, absorbing heat when ambient temperatures are high and releasing it when temperatures drop. This passive adaptation mechanism allows the sole structure to respond dynamically to environmental conditions without requiring complex active control systems, sensors, or power sources.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The phase change material performs thermal regulation autonomously based on temperature conditions, requiring no external control or energy input. The material self-adjusts its thermal properties through phase transitions, enabling the sole structure to adapt to environmental factors independently without adding complex control mechanisms.

Inventive Principle:
Principle #25Self-service

3Duration of action of moving object

If traditional insole designs are used, then simplicity is maintained, but comfort during prolonged exposure to hot surfaces is insufficient

Engineering Contradiction:
Improvecomfort durationVSAvoidinsole structure complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The phase change material provides extended comfort duration by cyclically absorbing and releasing thermal energy over time. During prolonged exposure to hot surfaces, the material continuously absorbs heat during phase transitions, maintaining comfortable foot temperatures for extended periods far beyond what traditional materials can achieve, while the passive nature of the mechanism avoids adding complex active cooling systems.

Inventive Principle:
Principle #36Phase transitions

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 sole structure effectively maintains foot temperature below the pain threshold for extended periods, providing comfort and reducing fatigue during athletic activities on hot surfaces by cyclically absorbing and releasing thermal energy.

Implementation Method 1

a phase change material disposed within the interior void and operable between a first state having a first viscosity and a second state having a second viscosity greater than the first viscosity

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

the phase change material transitions between solid and liquid states to absorb and release thermal energy

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 3

an insulating member, where the insulating member reduces thermal transfer from the ground surface to the foot

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3675672B1Cushioning arrangement for temperature control of a sole structure
Publication Date: 2024.01.03 NIKE INNOVATE CV
  • EP3675672B1 patent drawingFigure 1
  • EP3675672B1 patent drawingFigure 2
  • EP3675672B1 patent drawingFigure 3

AI summary

A sole structure (14) for an article of footwear (10) includes a chamber (52) having a first barrier element (54), a second barrier element (56), and a tensile member. The tensile member is disposed within an interior void (58) defined by the first barrier element and the second barrier element. The sole structure further includes a phase change material (70) disposed within the interior void and operable between a first state in a first temperature range and a second state in a second temperature range. The first temperature range is from 30°C to 35°C and the second temperature range is from 35°C to 42°C. The sole structure further includes an insulating member (50) disposed between the chamber and a ground contacting surface (72).