Motor Vehicle Door Lock Actuation Lever for Noise Reduction
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Solution Overview
Problem
Motor vehicle door latches often produce a disturbing 'double clack' noise during slow opening due to the pawl not being raised quickly enough from the catch, causing additional noise when it strikes the pre-ratchet recess.
Innovation Solution
The actuation lever is designed with a projection that interacts with the pawl spring only when the pawl is raised from the catch, ensuring the pawl spring is raised from the pawl, preventing a second clack noise by avoiding contact with the pre-ratchet recess during opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pawl spring acts continuously on the pawl in the closing direction, then the pawl is reliably returned to the basic position, but the pawl may strike the pre-ratchet recess and create additional noise during opening
Solution Approach 1:
The actuation lever is designed to preliminarily raise the pawl from the catch before the catch opens, ensuring the pawl is clear of the main ratchet recess. This preliminary action prevents the pawl from striking the pre-ratchet recess during opening, eliminating the second clack noise while maintaining reliable pawl positioning through the continuous acting pawl spring
2Speed
If the opening process is slow, then the pawl has time to be raised from the catch, but the pawl spring causes the pawl to move back and create additional noise
Solution Approach 1:
The actuation lever performs a preliminary raising action on the pawl, clearing it from the main ratchet recess before the catch opens. This ensures that even if the opening process is slow, the pawl cannot strike the pre-ratchet recess and create smashing noise, as it has already been positioned away from the catch
3Ease of operation
If the actuation lever only raises the pawl from the catch, then the locking mechanism opens, but the pawl spring may cause additional noise by moving the pawl back
Solution Approach 1:
The actuation lever is designed with an extended function: it not only raises the pawl from the catch but also preliminarily positions it away from the pre-ratchet recess. This dual action ensures smooth opening operation while preventing the pawl spring from causing the pawl to strike back and create additional noise
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 results in a single 'clack' noise when opening the locking mechanism, ensuring the catch opens quickly and quietly, with the pawl spring acting on the pawl only when necessary, reducing noise and improving the opening process.
Implementation Method 1
a pawl spring for acting on the pawl in the closing direction
Implementation Method 2
the actuation lever is additionally designed to act on the pawl spring
Data Source
AI summary
A motor vehicle door lock which is equipped with a locking mechanism that consists essentially of a rotary latch and a pawl. The lock also comprises a pawl spring for action on the pawl in the closing direction. The motor vehicle door lock further comprises an actuating lever for opening the locking mechanism. The actuating lever is additionally designed to act upon the pawl spring.