Vehicle Seat Bracket Yield Segment Energy Absorption
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Solution Overview
Problem
Vehicle seat backs made from polymeric materials face challenges in meeting structural requirements during crash events, such as rear impact collisions, where they must manage acceleration forces without exceeding deformation limits while reducing manufacturing costs and weight.
Innovation Solution
A bracket is used to couple the seating and back frame members, featuring a yield segment that plastically deforms to absorb impact forces, with a notch mechanism to restrict excessive rotation and deformation, ensuring safe occupant support by dissipating collision energy and controlling displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the seat back is made from polymeric material to reduce manufacturing costs and weight, then manufacturing cost and weight are reduced, but the structural strength and ability to meet crash event requirements deteriorate
Solution Approach 1:
The bracket is constructed from a polymeric material that combines strength and energy-absorbing properties. This composite material approach allows the seat back structure to achieve both weight reduction and sufficient structural strength for crash events, resolving the contradiction between using polymeric materials for cost/weight benefits and maintaining structural requirements.
2Force
If the yield segment is allowed to plastically deform to absorb impact energy, then impact force transferred to occupant is reduced, but the rotation of back frame member may exceed maximum deformation angle
Solution Approach 1:
The bracket notch is pre-formed in the bracket body to define a specific geometric constraint. This preliminary structural feature guides the plastic deformation of the yield segment to occur in a controlled manner, ensuring that energy absorption happens while the rotation remains within acceptable limits. The pre-designed notch geometry predetermines the deformation path and limits excessive rotation.
Solution Approach 2:
The bracket design incorporates a yield segment with specific geometric parameters that change during deformation. The plastic deformation is controlled to occur within defined parameters established by the bracket notch geometry, allowing the yield segment to absorb energy through controlled parameter changes while maintaining overall structural integrity and limiting rotation angle.
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 the impact force transferred to occupants during collisions, minimizing injury risk and allowing the use of polymeric materials that meet structural requirements while reducing manufacturing costs and weight.
Implementation Method 1
The front portion of the bracket defines a yield segment for plastically deforming when a force above a predetermined value is applied to the back frame member. Plastically deforming the yield segment reduces an impact force transferred from the seat to the occupant.
Data Source
AI summary
A bracket is used to couple together a seating frame member and a back frame member of a seat of a vehicle. The bracket comprises a periphery and a central longitudinal axis dividing the bracket into a front portion and a rear portion. The front portion of the bracket defines a yield segment for plastically deforming when a force above a predetermined value is applied to the back frame member. Plastically deforming the yield segment reduces an impact force transferred from the seat to an occupant. The periphery of the rear portion of the bracket includes a first contact surface and a second contact surface spaced from the first contact surface. The first contact surface moves into contact with the second contact surface as the yield segment plastically deforms thereby restricting the plastic deformation of the yield segment.