Vehicle Seat Bladder Control for Firmness Without H-Point Shift
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Solution Overview
Problem
Existing vehicle seats lack effective mechanisms to adjust firmness while maintaining the hip pivot point, which is crucial for occupant comfort and safety, as changes in seat firmness can disrupt the h-point's position.
Innovation Solution
The vehicle seat incorporates inflatable upper and lower bladders that adjust firmness by varying air pressure, with the lower bladder compensating for changes in the upper bladder's pressure to maintain the h-point's position, and additional mechanisms like variable tension springs and back support assemblies to ensure consistent hip pivot point alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the firmness of the seat cushion is adjusted by changing air pressure in the upper bladder, then the firmness is improved, but the hip pivot point position shifts
Solution Approach 1:
The lower bladder acts as a counterbalancing element to the upper bladder. When the upper bladder pressure is decreased to soften the seat, the lower bladder pressure is increased to compensate for the resulting h-point displacement. This counterbalancing pressure adjustment maintains the hip pivot point position while allowing firmness adjustment.
Solution Approach 2:
The system changes the physical parameters (air pressure) of the bladders dynamically. By independently controlling the pressure parameters of the upper and lower bladders, the system achieves both firmness adjustment and h-point position maintenance through coordinated parameter modification.
2Ease of operation
If the pressure in the upper bladder is decreased to achieve softer seating, then the comfort is improved, but the h-point position shifts downward
Solution Approach 1:
When the upper bladder is deflated to improve comfort, the lower bladder is simultaneously inflated to provide a counterbalancing upward force. This compensates for the downward shift caused by upper bladder deflation, maintaining the h-point position while achieving the desired softness.
Solution Approach 2:
The lower bladder serves as an intermediary element that mediates between the comfort requirement (upper bladder deflation) and the position requirement (h-point stability). By adjusting the lower bladder pressure, it bridges the gap between these two conflicting requirements.
3Adaptability or versatility
If multiple air bladders are used to adjust firmness, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The seat cushion is segmented into multiple functional zones using separate upper and lower bladders. This segmentation allows independent control of different regions, enabling nuanced firmness adjustment while maintaining overall h-point position through coordinated operation of the segmented elements.
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
This solution allows for adjustable firmness of the seat and seat back while maintaining the h-point's position, enhancing occupant comfort and safety by ensuring consistent support and protection during use.
Implementation Method 1
The cushion includes an inflatable first air bladder for selectively adjusting the firmness of the cushion
Implementation Method 2
The seat is configured such that a vehicle seat hip pivot point is maintained by counteracting a change in pressure within the first air bladder with an inverse change in pressure within the second air bladder
Data Source
AI summary
A vehicle seat includes a seat back and a seat for supporting an occupant. A cushion is coupled to the seat and has at least one inflatable upper bladder for selectively adjusting the firmness of the cushion. The seat further includes an inflatable lower bladder positioned beneath the upper bladder. The seat is configured such that a vehicle seat hip pivot point is maintained when adjusting the firmness of the cushion by increasing the pressure in the lower bladder when the pressure in the upper bladder is selectively decreased, and by decreasing the pressure in the lower bladder when the pressure in the upper bladder is selectively increased.