Vehicle Seat Slide Device Crash Force Management
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Solution Overview
Problem
Existing slide devices for vehicle seats face challenges in maintaining smooth front-rear movement during a frontal crash, particularly in three-row seating vehicles, as they cannot effectively manage the forces applied to the upper rail, leading to potential bending of the lower rail and hindrance of seat movement, which is exacerbated by the need for increased rigidity and weight.
Innovation Solution
A slide device configuration that includes a downward-moving bracket attached to the upper rail, which absorbs downward forces and a J hook member to regulate upward forces, dispersing these forces through a reinforcement member without enhancing the lower rail's rigidity, allowing the seat body to move freely in the front-rear direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the lower rail is made of highly rigid material to prevent bending during frontal crash, then the resistance to deformation improves, but the weight increases and cost increases
Solution Approach 1:
The lower rail is divided into a front portion and a rear portion with different rigidity characteristics. The front portion has lower rigidity to allow controlled bending and absorb crash energy, while the rear portion maintains sufficient rigidity to prevent excessive deformation. This segmentation resolves the contradiction by providing location-specific rigidity rather than uniform high rigidity throughout the entire lower rail.
Solution Approach 2:
Different portions of the lower rail are designed with different rigidity properties to meet local requirements. The front portion is designed with lower rigidity to accommodate crash forces through controlled deformation, while the rear portion maintains higher rigidity for structural stability. This local differentiation eliminates the need for uniformly high rigidity, thereby reducing overall weight and cost.
2Strength
If the lower rail is made of highly rigid material to prevent bending during frontal crash, then the resistance to deformation improves, but the cost increases
Solution Approach 1:
The lower rail is segmented into front and rear portions with different rigidity characteristics. This segmentation allows the use of less expensive materials or manufacturing processes for the front portion that can tolerate controlled deformation, while the rear portion uses more rigid construction. The overall cost is reduced compared to manufacturing the entire lower rail with uniformly high rigidity.
Solution Approach 2:
Different portions of the lower rail are designed with different rigidity properties appropriate to their functional requirements. The front portion accepts lower rigidity to manage crash forces, while the rear portion maintains higher rigidity for structural support. This local differentiation reduces material costs and manufacturing complexity compared to uniform high-rigidity construction.
3Reliability
If the lower rail is enhanced in rigidity to prevent bending during frontal crash, then the reliability improves, but the weight increases
Solution Approach 1:
The lower rail is segmented into front and rear portions with different rigidity characteristics. The front portion's controlled flexibility ensures reliable seat movement during crash by allowing energy absorption, while the rear portion provides structural reliability. This segmentation achieves crash reliability without the weight penalty of uniformly rigid construction.
Solution Approach 2:
Different portions of the lower rail are designed with different rigidity properties to meet local reliability requirements. The front portion's lower rigidity enables reliable crash force management through controlled deformation, while the rear portion's higher rigidity ensures structural reliability. This local differentiation achieves overall system reliability without excessive weight.
Data Source
AI summary
A slide device for a vehicle seat provided with: an upper rail that is long in the front-rear direction and fixedly installed on the bottom surface of a seat body; a lower rail that is arranged on the floor of a vehicle body and supports the upper rail such that the upper rail can slide in the front-rear direction; a bracket that is fixedly installed at the front of the upper rail and moves downward with thereof when the upper rail moves tilting forward; a J hook member that moves upward with the upper rail upon the upward movement of the rear thereof; and a reinforcement member to which the bracket is abutted upon the downward movement thereof so as to absorb a downward force and to which the J hook member is abutted upon the upward movement thereof so as to absorb an upward force.