Vehicle Seat Backrest Subframe Rearward Displacement Mechanism
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Solution Overview
Problem
Existing vehicle-mounted seat devices fail to adequately protect occupants from whiplash injuries during rear collisions, as the body sinks less than the head, causing excessive rearward movement of the head relative to the body, due to the design of backrests supported by linear members or thick cushioning.
Innovation Solution
A vehicle-mounted seat device with a seatback main frame, a backrest suspended by a suspension tool capable of swinging, and front-back position regulation mechanisms that include a restraining member with a weak portion that deforms under load, allowing the seatback subframe to move rearward and increase body sinking, reducing head movement relative to the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the backrest is supported by linear members (tensile force structure), then the backrest can swing and provide cushioning, but the body sinks only a small amount during rear collision, causing the head to swing far rearward and increasing whiplash risk
Solution Approach 1:
The position regulation mechanism transforms the rigid backrest structure into a dynamic system that can adapt its position during collision. The subframe is designed to move rearward relative to the main frame when subjected to impact forces, allowing the backrest to dynamically adjust and reduce head-to-body displacement difference, thereby mitigating whiplash while preserving swingability during normal operation
Solution Approach 2:
The mechanism changes the positional parameter of the subframe relative to the main frame during collision. By allowing the subframe to displace rearward by a predetermined amount, the system modifies the backrest's effective position to reduce the relative movement between head and body, directly addressing the whiplash problem while maintaining the cushioning function
2Object-affected harmful factors
If thick cushion members are used, then the body can sink far rearward, but the head-to-body movement difference is reduced, which should help prevent whiplash; however, this increases device complexity and weight
Solution Approach 1:
The invention extracts the collision protection function from the cushioning system and implements it through a separate position regulation mechanism. Instead of relying solely on thick cushions to provide both comfort and collision protection, the design separates these functions: thin cushions provide comfort while the subframe displacement mechanism provides collision protection, reducing overall structural complexity
Solution Approach 2:
The position regulation mechanism acts as an intermediary between the main frame and subframe during collision. This intermediary mechanism controlled by the displacement limit member enables precise control over the subframe's rearward movement, providing whiplash protection through a controlled, predetermined displacement rather than uncontrolled sinking
3Object-affected harmful factors
If the position regulation mechanism allows large rearward movement of the subframe, then body sinking increases and whiplash is reduced, but the maximum pulling load of the restraining member increases
Solution Approach 1:
The displacement limit member is pre-configured to allow controlled rearward movement of the subframe before full collision forces are applied. This preliminary controlled displacement reduces the peak forces that would otherwise be transmitted through the restraining member, managing the load profile to protect against whiplash while controlling maximum pulling loads
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 design effectively reduces whiplash occurrence by allowing the body to sink further than the head during a rear collision, enhancing protection for the occupant and ensuring effective functioning of seat belts and airbags.
Implementation Method 1
the arm portion is deformed upon input of a larger load than a predetermined load such that the front end portion thereof is displaced rearward relative to the rear fixing portion
Implementation Method 2
a restraining member that is a linear member strung between the front fixing portion and the rear fixing portion, the restraining member being for regulating the rearward movement of the seatback subframe relative to the seatback main frame
Implementation Method 3
a backrest held by being suspended from the seatback main frame with a suspension tool, the backrest being capable of swinging relative to the seatback main frame
Data Source
AI summary
A vehicle-mounted seat device includes an SB main frame, a backrest, an SB subframe, and one or more front-back position regulation mechanisms for regulating the position of the SB subframe in the front-back direction relative to the SB main frame. Each front-back position regulation mechanism includes a front restraining bracket secured relative to the SB main frame, a rear restraining bracket secured on the SB subframe, and a front-back wire strung between the front and rear restraining brackets. The rear restraining bracket is deformed such that its front end portion is displaced rearward relative to its end portion upon input of a load greater than a predetermined load. A maximum pulling load of the front-back wire is greater than a load that causes initial deformation of the rear restraining bracket.