Motor Vehicle Lock Switchable Coupling Crash Safety
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Solution Overview
Problem
Existing motor vehicle locks face challenges in crash safety due to undesirable reaction times and high material costs resulting from the need for a separate crash element and complex drive train design, which can lead to unpredictable breakage during crashes.
Innovation Solution
A motor vehicle lock with a switchable coupling arrangement between the pawl actuation lever and the pawl, utilizing a coupling element that controls its own movement and actuation, reducing components and ensuring the pawl actuation lever runs free during rapid actuation, thus preventing unintended door opening during crashes without compromising crash safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate crash element is used to block the pawl actuation lever during crashes, then crash safety is improved, but device complexity and material costs increase
Solution Approach 1:
The patent combines the crash element with the existing pawl actuation lever into a single integrated component. The lever itself is designed with a geometric feature (the blocking protrusion) that serves as the crash element, eliminating the need for a separate crash blocking component. This merging reduces device complexity while maintaining crash safety functionality.
Solution Approach 2:
The pawl actuation lever is designed to serve multiple functions: normal operation actuation, crash-induced blocking, and providing the blocking geometry through its own structure. The lever's L-shaped cross-section and integrated blocking protrusion allow it to function as both the actuation mechanism and the crash safety element, reducing the need for additional components.
2Reliability
If the crash element moves into a blocking position before intended blocking, then crash safety function is activated, but reaction time is delayed
Solution Approach 1:
The blocking protrusion is pre-positioned on the lever in a ready state during normal operation. During a crash, the lever rotates about its pivot point, and the pre-positioned blocking protrusion immediately engages with the receiving structure without requiring any additional movement or activation step. This preliminary positioning eliminates reaction time delay.
Solution Approach 2:
The crash blocking mechanism utilizes the dynamic rotation of the lever about its pivot point during crash deceleration. The lever's movement during normal actuation is repurposed during a crash to automatically engage the blocking protrusion, transforming the lever's dynamic motion into an immediate crash response without requiring separate activation.
3Reliability
If the drive train is designed for exceptionally high forces to prevent breakage during crashes, then reliability is improved, but material costs and manufacturing complexity increase
Solution Approach 1:
The patent extracts the crash blocking function from the drive train components and places it on the pawl actuation lever itself. By removing the requirement for the drive train to withstand crash forces, the design can use standard-strength materials and conventional manufacturing processes, significantly reducing material costs and manufacturing complexity while maintaining reliability through the separate blocking mechanism.
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 provides a cost-effective construction that maintains high crash safety by ensuring the pawl actuation lever does not deflect into a release position during rapid actuation, thereby preventing unintended door opening, while also serving as a locking/unlocking mechanism.
Implementation Method 1
the actuation of the pawl actuation lever always goes along with moving the coupling element into its closing position such that in the end the actuation of the pawl actuating lever causes the deflection of the pawl into its release position. However, the proposed motor vehicle lock may be configured such that during very fast actuation of the pawl actuation lever the coupling element does not reach its closing position quick enough in order to deflect the pawl into its release position. This is very useful in a crash situation as crash accelerations often lead to very fast actuation of the pawl actuation lever. As the delay of the coupling element reaching its closing position mainly goes back on mass inertia regarding the mass of the coupling element, this delay may easily configured by choosing a corresponding weight distribution at the coupling element.
Data Source
AI summary
The invention is directed to lock for a vehicle door arrangement, wherein a catch and a pawl are provided. The catch can be brought into an opening position and into a closed position, wherein the catch, which is in the closed position, is or may be brought into holding engagement with a lock striker. The pawl may be brought into an engagement position. A pawl actuation lever is provided for deflecting the pawl into the release position. A switchable coupling arrangement comprises a first coupling lever on the side of the pawl actuation lever, a second coupling lever on the side of the pawl and a moveable coupling element that may be moved into a closing position for a coupling engagement with the two coupling levers and into an opening position for decoupling the two coupling levers. The coupling element is arranged on one of the two coupling levers.