Vehicular seat element
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Solution Overview
Problem
Conventional vehicular seats, designed for the 50th percentile of male passengers, fail to provide adequate comfort for a broader range of passengers, including larger individuals, tall individuals, and women and children, due to their uniform specification profile across all operation temperatures, leading to discomfort from pressure applied to the under-thigh region.
Innovation Solution
A vehicular seat element featuring a rate-sensitive foam element on the occupant-contacting surface combined with a conventional high resiliency polyurethane foam core, which reduces pressure on the under-thigh area by using a viscoelastic foam with a glass transition temperature above -20°C, providing improved comfort across a wider range of passenger sizes and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional high resiliency polyurethane foam is used for the entire seat element, then the seat provides adequate support for 50th percentile male passengers, but it applies excessive pressure to the under-thigh region of passengers outside this percentile (including women, children, and larger individuals)
Solution Approach 1:
The patent applies a rate-sensitive foam layer specifically to the under-thigh region (anterior portion) of the seat element, while using conventional HR foam for the rest of the seat. This localized application allows the anterior portion to adapt to different passenger sizes and reduce pressure on the under-thigh region, while maintaining adequate support elsewhere. The rate-sensitive foam's ability to soften under sustained load provides differential comfort zones within the seat element.
Solution Approach 2:
The patent utilizes the temperature-dependent and time-dependent mechanical properties of rate-sensitive foam to dynamically adjust the seat's pressure distribution. The rate-sensitive foam exhibits different stiffness characteristics based on loading rate and temperature, automatically adapting to different passenger sizes and environmental conditions. This parameter-based adaptation allows a single seat element to provide comfort across a wider range of passengers without requiring multiple customization options.
2Stability of the object's composition
If a uniform foam specification profile is used across all operation temperatures, then the seat maintains consistent structural properties, but it fails to adapt to temperature variations that affect passenger comfort
Solution Approach 1:
The patent incorporates rate-sensitive foam whose mechanical properties change in response to temperature and loading rate variations. This allows the seat element to automatically adapt its characteristics based on environmental conditions and passenger size, while the underlying HR foam core maintains structural integrity. The rate-sensitive foam's viscoelastic properties enable dynamic adjustment of comfort characteristics without compromising overall seat stability.
Solution Approach 2:
The patent creates a composite structure combining rate-sensitive foam and conventional HR polyurethane foam, each material contributing different properties. The HR foam provides stable structural support and durability, while the rate-sensitive foam layer adds adaptability to temperature and loading conditions. This composite approach allows the seat to simultaneously achieve structural consistency and environmental adaptation.
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 combination of rate-sensitive and high resiliency foams in the vehicular seat element significantly reduces pressure on the under-thigh region, enhancing comfort for a broader range of passengers, from the 5th to 95th percentile in terms of weight and height, as demonstrated by static and dynamic testing.
Implementation Method 1
a rate sensitive foam element secured with respect to the foam core element, the foam core element and the rate sensitive foam element being different
Data Source
Figure 1
AI summary
There is disclosed a vehicular seat element comprising a first major surface, a second major surface and a foam core element disposed therebetween. The first major surface is configured to be in contact with an occupant of the vehicle and the second major surface is configured to be in contact with a support surface of the vehicle. The first major surface comprises a rate sensitive foam element secured with respect to the foam core element. The foam core element and the rate sensitive foam element are different from one another.