Belt Tensioner Plastically Deformable Stop Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing belt tensioners for seat belts face challenges in achieving reliable sealing of the pressure cylinder and optimal piston abutting behavior, often requiring precise manufacturing tolerances or additional sealing elements.
Innovation Solution
A belt tensioner design featuring a stop made of plastically deformable material that deforms upon piston abutment, enhancing sealing contact and allowing for adjustable piston deceleration through material and geometric choices, with a constriction or cutting edge facilitating proper sealing and preventing piston tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stop is made rigid with precise manufacturing tolerances to ensure sealing, then sealing reliability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The stop is designed with a deformable geometry that changes from its initial state to a deformed state upon piston contact. The stop initially has a first geometry with a gap, and when deformed by the piston, it adopts a second geometry that provides sealing contact, thereby achieving reliable sealing through geometric transformation rather than precise manufacturing tolerances
Solution Approach 2:
The stop is constructed from composite or specially selected materials with specific mechanical properties (yield strength, elasticity) that enable controlled plastic deformation. This material selection allows the stop to deform reliably under piston load while maintaining structural integrity, providing both sealing function and durability without requiring high manufacturing precision
2Loss of time
If the piston decelerates quickly upon hitting the stop, then response time is improved, but harmful factors increase due to shock and potential damage
Solution Approach 1:
The stop is designed to undergo controlled plastic deformation that absorbs impact energy. By allowing the stop material to yield and deform in a controlled manner, the system cushions the piston's deceleration, reducing shock and potential damage while maintaining relatively quick response time
Solution Approach 2:
The stop's geometric parameters change during deformation, creating a progressive resistance to piston motion. This geometric transformation allows the deceleration profile to be optimized - initially allowing faster deceleration then providing increasing resistance to reduce shock, thereby balancing response time and harm reduction
3Reliability
If additional sealing elements are added to ensure sealing, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The stop serves multiple functions simultaneously: it provides the mechanical end-stop for piston travel, creates the sealing contact with the pressure cylinder wall through its deformation, and absorbs impact energy. This multi-functionality eliminates the need for separate sealing elements, reducing device complexity while maintaining sealing reliability
Solution Approach 2:
The sealing function is merged with the stop structure itself. Rather than being a separate component, the sealing capability is integrated into the stop's geometry and deformation behavior, combining what would traditionally be separate functions into a single unified component
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 improves sealing efficiency and deceleration control of the piston, ensuring reliable fluid containment and preventing fluid escape, while allowing for flexible design adaptations to optimize performance.
Implementation Method 1
the stop is provided to consist of plastically deformable material and to be plastically deformed by the piston at the end position so that the piston is in sealing contact with the inside of the pressure cylinder
Data Source
AI summary
The invention provides in a best tensioner (10), especially a rotary tensioner, for a seat belt comprising an elongate and preferably cylindrical pressure cylinder (129, a piston (18) movably supported in the pressure cylinder (12) in the longitudinal direction which is adapted to be pressurized with fluid under pressure and thus to be moved into a tensioning direction (S), a thrust means (20) interacting with the piston (18) and a stop (24) provided on the inside (38) of the pressure cylinder (12) to which the piston (18) can be adjacent in the tensioning direction (S) at an end position at which the piston (18) seals the pressure cylinder (12), that the stop (24) is made of a plastically deformable material and is plastically deformed by the piston (18) at the end position so that the piston is in sealing contact with the inside of the pressure cylinder (12).