Footwear Footbed Projections for Lower-Friction Foot Sliding
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Solution Overview
Problem
In footwear manufactured by three-dimensional additive manufacturing, the large contact area between the footbed portion and the wearer's foot leads to increased friction, making it difficult for the wearer to slide the foot along the footbed, particularly when the material selection is restricted.
Innovation Solution
The footwear features a footbed portion with upper surface-side projection portions arranged to reduce contact area, having dimensions and arrangement densities that allow smooth sliding and improved air permeability, made from elastic materials with specific elastic moduli and manufactured using a vat polymerization-type three-dimensional additive manufacturing method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the contact area between footbed portion and wearer's foot is increased, then support area is improved, but friction increases making it difficult to slide foot in
Solution Approach 1:
The footbed portion is designed with a mesh structure comprising interconnected struts forming void spaces, creating a porous material that reduces effective contact area while maintaining structural integrity. This allows reduced friction for easier foot insertion while preserving support functionality through the distributed strut network.
Solution Approach 2:
The mesh structure creates local variations in contact properties throughout the footbed surface. Different regions have different strut arrangements and void distributions, providing localized contact characteristics that balance support and slippage requirements in different foot zones.
2Ease of operation
If mesh structure is used to reduce contact area, then sliding ease is improved, but structural strength may be reduced
Solution Approach 1:
The continuous footbed structure is segmented into discrete struts connected at nodes, forming a modular mesh network. This segmentation reduces material usage and contact area while distributing mechanical loads across multiple structural elements, maintaining overall strength through the interconnected geometry.
Solution Approach 2:
The footbed combines solid strut material with void spaces to create a composite-like structure. The solid-strut-void composite provides both mechanical strength from the strut network and reduced contact area from the void spaces, achieving both structural integrity and sliding ease.
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 solution provides improved slippage and comfort by reducing friction, enhancing air permeability, and ensuring easy foot insertion and wear, while maintaining lightweight and shock-absorbing properties.
Implementation Method 1
an elastic modulus of a material constituting the plurality of upper surface-side projection portions is greater than or equal to 0.1 MPa and less than or equal to 100 MPa
Implementation Method 2
manufactured using a vat polymerization-type three-dimensional additive manufacturing method
Data Source
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AI summary
Footwear (1A) includes a footbed portion (21). The footbed portion (21) includes a support region (26) supporting a foot sole of a wearer's foot on an upper surface thereof, and the support region (26) includes an upper surface-side projection portion forming region (30a) in which a plurality of upper surface-side projection portions are arranged to stand side by side. A maximum outer dimension in a cross-section orthogonal to a projecting direction of each of the plurality of upper surface-side projection portions is less than or equal to 3.0 mm. A projection length of each of the plurality of upper surface-side projection portions is greater than or equal to 4.0 mm and less than or equal to 13.0 mm, and an arrangement density of the plurality of upper surface-side projection portions in the upper surface-side projection portion forming region (30a) is greater than or equal to 10% and less than or equal to 100% in terms of an area ratio. An elastic modulus of a material forming the plurality of upper surface-side projection portions is greater than or equal to 0.1 MPa and less than or equal to 100 MPa.