Vehicle seat structure
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Solution Overview
Problem
Existing vehicle seat designs fail to adequately reduce occupant incongruity during vehicle acceleration while maintaining holdability, as they either compromise holdability by lowering the seat back's spring constant or struggle to suppress backward inclination of the upper body.
Innovation Solution
A vehicle seat structure with distinct support sections for the upper and lower thoracic spine, where the lower thoracic support section is designed to displace backward more than the upper thoracic support section under inertia, generating a forward rotational moment to incline the upper thoracic spine forward and suppress head inclination, and incorporating varying spring constants to maintain physiological lordosis and support comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the seat back's spring constant is lowered to suppress backward inclination of the upper body during acceleration, then the occupant's head inclination is reduced, but the holdability of the seat deteriorates
Solution Approach 1:
The seat back is divided into multiple support sections with different spring constants: a first support section (upper thoracic region) with a higher spring constant and a second support section (lower thoracic region) with a lower spring constant. This segmentation allows differential response to acceleration forces, suppressing head inclination while maintaining overall holdability.
Solution Approach 2:
Different regions of the seat back are assigned different local properties (spring constants) based on their functional requirements. The upper thoracic region has higher stiffness for head control, while the lower thoracic region has lower stiffness for body compliance, achieving both head inclination reduction and holdability maintenance.
2Stability of the object's composition
If the seat back is formed to align with the physiological lordosis, then the spinal curve is maintained during steady traveling, but the occupant may feel incongruity during acceleration
Solution Approach 1:
The seat back transitions from a static, uniform structure to a dynamic, differentiated structure where support characteristics change based on acceleration conditions. During acceleration, the differential spring constants create relative movement between support sections that actively counteracts head inclination while maintaining spinal alignment during steady state.
Solution Approach 2:
The seat back is segmented into multiple support sections with different spring constants to provide region-specific response. This segmentation enables the seat back to maintain physiological lordosis during steady traveling while reducing head inclination during acceleration, eliminating occupant incongruity.
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 effectively reduces occupant incongruity and maintains holdability by individually adjusting the backward movement of skeletal parts, ensuring the occupant's spinal alignment and comfort during acceleration, while allowing secure steering operations.
Implementation Method 1
when backward inertia force acts on the seated occupant, the lower thoracic support section 20b is displaced backward greatly, as compared with the upper thoracic support section 20a according to the inertia force
Data Source
AI summary
A seat back (20) includes an upper thoracic support section (20a) for supporting at least a portion corresponding to a lower part of the upper thoracic spine of a seated occupant, and a lower thoracic support section (20b) disposed on a front side with respect to the upper thoracic support section (20a) and configured to support a portion corresponding to the lower thoracic spine of the seated occupant. The lower thoracic support section (20b) is configured to displace backward greatly, as compared with the upper thoracic support section (20a) in such, a way that the upper thoracic spine of the seated occupant is inclined forward, when backward inertia force acts on the seated occupant.