Adaptive Seat Stiffness Tensioning to Prevent Occupant Submarining
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Solution Overview
Problem
Vehicle seats with fixed suspension system stiffness fail to adequately restrain occupants during vehicle acceleration, leading to potential submarining due to increased gap between seatbelt and seat, as they cannot dynamically adjust to changing occupant loads and vehicle dynamics.
Innovation Solution
A self-adjusting seat stiffness system featuring a tension member and tensioning unit that automatically adjusts seat stiffness in response to perceived vehicle dynamic events, such as acceleration or potential collisions, using a controller that communicates with vehicle systems to maintain or increase tension in the tension member, potentially assisted by an inflatable member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the seat suspension system uses fixed stiffness springs and foam, then the seat provides consistent structural support, but the seat cannot dynamically adjust to changing occupant loads and vehicle dynamics during acceleration
Solution Approach 1:
The patent applies the Dynamics principle by replacing the fixed stiffness suspension system with an active tensioning system that dynamically adjusts seat stiffness in real-time. The tension member (webbing or strap) connected to a tensioning unit (retractor mechanism) allows the seat to transition from a static to a dynamic configuration, automatically adapting to changing occupant loads and vehicle acceleration conditions without requiring complex manual intervention.
Solution Approach 2:
The patent implements the Self-service principle through the tensioning unit's automatic operation. The retractor mechanism (such as a reel-based system with spring or electromagnetic actuator) automatically tensions or relaxes the tension member in response to detected vehicle dynamics or occupant movement, eliminating the need for manual adjustment by the occupant while maintaining optimal seat stiffness and restraint geometry.
2Reliability
If the seat uses fixed stiffness suspension, then the seat structure remains simple, but the gap between seatbelt and seat increases during acceleration allowing submarining
Solution Approach 1:
The patent applies the Dynamics principle by introducing a dynamic tensioning system that actively maintains the optimal geometry between the seatbelt and seat during vehicle acceleration. The tension member connected to the tensioning unit dynamically adjusts to prevent seat compression that would create gaps, thereby maintaining reliable occupant restraint without requiring a completely redesigned seat structure.
Solution Approach 2:
The patent uses the tension member (webbing or strap) as an intermediary element between the tensioning unit and the seat structure. This intermediary component transmits the active tensioning force to maintain seatbelt geometry, allowing the system to improve restraint reliability while keeping the overall seat structure relatively simple and modular.
3Ease of operation
If the seat uses softer suspension for comfort, then occupant comfort increases, but occupant support and seatbelt restraint during acceleration decrease
Solution Approach 1:
The patent applies the Dynamics principle by enabling the seat suspension to transition between soft and stiff states. During normal conditions, the softer foam and spring suspension provides comfort. During detected acceleration events, the tensioning unit activates to tension the tension member, dynamically stiffening the seat structure to provide both comfort and reliable occupant support and seatbelt restraint.
Solution Approach 2:
The patent implements periodic action through the controller's monitoring and activation of the tensioning unit. The controller continuously monitors vehicle dynamics (acceleration, deceleration) and periodically activates the tensioning system when threshold conditions are met, allowing the seat to alternate between comfort-oriented soft states and safety-oriented stiff states based on real-time vehicle operation.
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 system effectively maintains or reduces the gap between the seat and seatbelt, enhancing occupant restraint and preventing submarining by dynamically adjusting seat stiffness in response to vehicle dynamics, thereby improving safety and comfort.
Implementation Method 1
The tensioning unit may be an inertial-latching retracting spool
Implementation Method 2
The system may also have an inflatable member connected to the tension member. The inflatable member may be deployable in response to a perceived vehicle dynamic event
Data Source
AI summary
A self-adjusting seat stiffness system that uses a tension member and tensioning device to maintain or increase tension in a seat component during a perceived vehicle dynamic event. The system may use an inertial latching spool for the tensioning device as an example of a way to maintain tension at a target acceleration of the spool by locking up the tension member, or may have a controller to control the tensioning member to provide variable tensions depending on varying perceived vehicle parameters. The tensioning of the tension member helps to avoid submarining of an occupant under a seatbelt due to unacceptable seat compression during a vehicle dynamic event.