Segmented Midsole Hardness for Heel Cushioning and Talus Stability
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Solution Overview
Problem
Conventional shoe sole structures with higher cushioning properties tend to cause overpronation, leading to instability and chronic pain in the lower limbs due to uniform cushioning distribution across the foot width, which fails to adequately support the sustentaculum tali area.
Innovation Solution
A shoe sole structure featuring a midsole with a first portion of relatively low hardness at the calcaneus area and a second portion of higher hardness from the sustentaculum tali to the navicular area, providing enhanced cushioning at the heel and increased rigidity to stabilize the sustentaculum tali, thereby reducing overpronation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the midsole has high cushioning properties throughout the foot width direction, then the impact attenuation at the heel portion is improved, but the calcaneus becomes unstable and overpronation occurs
Solution Approach 1:
The midsole is divided into different hardness zones: a first midsole portion with lower hardness at the heel portion for impact attenuation, and a second midsole portion with higher hardness at the sustentaculum tali and navicular areas for stability. This local differentiation allows each region to perform its specific function optimally without causing overpronation.
Solution Approach 2:
The midsole is segmented into multiple portions with different material properties. The first midsole portion (lower hardness) handles impact absorption at the heel, while the second midsole portion (higher hardness) provides structural support and stability at the sustentaculum tali and navicular regions, preventing excessive calcaneus movement.
2Ease of operation
If the midsole has uniform thickness and hardness from inner side to outer side, then the cushioning properties are uniformly distributed, but the sustentaculum tali area lacks adequate support
Solution Approach 1:
Instead of uniform midsole properties, the invention implements location-specific characteristics: the first midsole portion at the heel has lower hardness for cushioning, while the second midsole portion at the sustentaculum tali and navicular has higher hardness for support, with each portion optimized for its specific anatomical region.
Solution Approach 2:
The hardness parameter of the midsole material is changed across different regions. The first midsole portion uses material with lower hardness (higher cushioning), while the second midsole portion uses material with higher hardness (more support), creating a gradient that matches the functional requirements of different foot areas.
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 proposed sole structure effectively attenuates impact on the heel while stabilizing the sustentaculum tali, reducing overpronation and enhancing the overall running experience by balancing cushioning and supporting properties.
Implementation Method 1
The second midsole portion is made of a material having a lower hardness than a material forming the first midsole portion... improves cushioning properties at the locations corresponding to the tuber bottom portion of the calcaneus... attenuate an impact particularly on a heel portion of the wearer upon grounding
Implementation Method 2
The first midsole portion and the second midsole portion have a relatively-high hardness in an area ranging from a location corresponding to a sustentaculum tali of the foot of the wearer to a location corresponding to a navicular of the foot of the wearer... enhances rigidity... improves supporting properties particularly at the location of the sustentaculum tali
Data Source
AI summary
To achieve a favorable feeling particularly during running. A midsole includes: a first midsole portion; and a second midsole portion stacked on the first midsole portion in a thickness direction of the midsole and made of a material having a lower hardness than a material forming the first midsole portion. In a cutting plane when the midsole is cut along a foot width direction at a location corresponding to the sustentaculum tali of a foot of a wearer, the first midsole portion and the second midsole portion have a relatively-low hardness at a location corresponding to the calcaneus of the wearer, and a relatively-high hardness in an area ranging from a location corresponding to the sustentaculum tali to a medial instep side.