Vehicle Seat Cushion Hardness Gradient for Sensor Protection
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Solution Overview
Problem
Current vehicle seat assemblies lack a cost-effective and simple method to create a hardness gradient with rigid inboard and outboard bolster areas and a softer center portion, which leads to premature wear and discomfort due to occupant sensing systems being damaged by the weight of occupants.
Innovation Solution
A vehicle seat assembly with a cushion having a hardness gradient between 8% to 25% between the bolster areas and the central portion, achieved through geometric intrusions and protrusions on the foam surface, allowing for improved durability and comfort by varying the foam density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid sensors are used for occupant sensing systems, then sensing function is achieved, but sensor damage and cushion wear occur due to weight loading
Solution Approach 1:
The foam cushion is configured with different hardness levels in different regions: a first hardness in the sensor region and a second hardness in the non-sensor region. This local quality differentiation allows the sensor area to be softer, protecting both the sensor and cushion from wear, while maintaining adequate support in other areas.
Solution Approach 2:
The patent changes the physical parameter of foam density/hardness in the sensor region compared to the non-sensor region. By reducing the hardness parameter locally where sensors are positioned, the system protects sensors from damage while maintaining overall cushion functionality.
2Ease of manufacture
If uniform foam density is used throughout the cushion, then manufacturing is simple, but inboard and outboard areas lack sufficient rigidity for load bearing
Solution Approach 1:
The foam cushion features non-uniform density distribution with higher density in inboard and outboard bolster areas and lower density in the center seating area. This local quality variation provides the necessary rigidity in load-bearing regions while maintaining comfort in the seating area, all within a single molded foam piece.
Solution Approach 2:
The patent creates a composite-like structure within a single foam material by varying the foam density across different regions. This internal composite structure combines hard bolster areas with a softer center area, achieving both structural support and comfort without requiring multiple materials or assembly steps.
3Ease of operation
If softer foam is used in the center portion for comfort, then occupant comfort is improved, but the inboard and outboard areas become insufficiently rigid
Solution Approach 1:
The foam cushion is designed with spatially varying density: softer in the center portion for comfort and harder in the inboard and outboard bolster areas for load bearing. This local quality differentiation simultaneously achieves both comfort and structural support requirements.
Data Source
AI summary
In at least one embodiment, the present invention provides a vehicle seat assembly comprising a cushion having an “A” surface and a “B” surface, a central portion, and two bolster areas, with each bolster area being adjacent the central portion, with the cushion having a hardness gradient between at least one of the bolster areas and the central portion of between 8% to 25%.