Vehicle Seat Belt Buckle Force Limiter Compact Rotational Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing pipe type force limiter mechanisms in vehicle seat belt buckle devices tend to increase in length during shock absorption, causing interference with vehicle components and making it difficult to mount them in narrow spaces, especially when electrical wires and their covers are present between the floor tunnel and the vehicle seat.
Innovation Solution
A buckle device with a force limiter mechanism that includes a take-up shaft supported below the buckle body for rotational movement, where a connecting member is wound around the shaft, and an energy-absorbing torsion shaft is deformed during collisions to absorb shock, maintaining a compact size by limiting the displacement of the buckle body and reducing the overall size of the force limiter mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pipe type force limiter mechanism is used for shock absorption, then shock absorption function is achieved, but the mechanism becomes longer in proportion to displacement, causing interference with floor components and making mounting difficult in narrow spaces
Solution Approach 1:
The force limiter mechanism transitions from a linear extension design to a rotational design. The take-up shaft rotates about a horizontal axis perpendicular to the seat belt direction, converting linear displacement into rotational motion. This dimensional change allows the mechanism to absorb shock without increasing its length in the vertical direction, solving the interference problem with floor components while maintaining the shock absorption function.
Solution Approach 2:
The mechanism employs a flexible connecting member that can dynamically change its configuration during shock absorption. The connecting member transitions from a wound state around the take-up shaft to an unwound state, allowing the system to absorb energy through controlled deformation while maintaining a compact form factor when not in use.
2Reliability
If the buckle device is designed with sufficient shock absorption stroke, then shock absorption performance is improved, but the overall size of the force limiter mechanism increases, reducing mountability in tight spaces
Solution Approach 1:
By converting the shock absorption motion from linear to rotational, the mechanism achieves sufficient shock absorption stroke without proportionally increasing its volume. The rotational take-up shaft can accommodate multiple windings of the connecting member, allowing for a longer effective shock absorption stroke within a compact cylindrical volume, thereby improving shock absorption performance without increasing overall size.
Solution Approach 2:
The connecting member is wound around the take-up shaft in a nested configuration, allowing the shock absorption mechanism to be compact. During normal operation, the connecting member is tightly wound around the shaft, minimizing the mechanism's volume. During shock absorption, the connecting member unwinds, providing the necessary stroke without requiring a large overall structure.
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 compact design of the buckle device improves mountability on vehicles by reducing interference with other components and allowing for efficient shock absorption without increasing the size of the force limiter mechanism, even in tight spaces.
Implementation Method 1
an energy absorbing member that is deformed by rotation of the take-up shaft
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A buckle device (10) includes: a buckle body (50) to which a tongue portion (48) mounted on a three-point seat belt is to be connected; a connecting member (54) that is flexible and that has a first longitudinal end portion connected to the buckle body; and a force limiter mechanism (56) including a take-up shaft (68) around which a second longitudinal end portion of the connecting member is wound, the take-up shaft being supported below the buckle body in a vertical direction of a vehicle so as to be rotatable relative to a vehicle seat or a vehicle body, and an energy absorbing member (86) that is deformed by rotation of the take-up shaft.