Motor Vehicle Lock Brake Latch Noise Reduction
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Solution Overview
Problem
Motor vehicle latch locking mechanisms often produce noise, known as an 'opening plop', when the pawl is moved out of its ratchet position due to the abrupt acceleration of the catch and pawl, which existing solutions fail to adequately prevent.
Innovation Solution
A latch with a brake latch and a towing arm mechanism that transmits rotational movement to lift the brake latch out of its braking position, reducing noise by ensuring a controlled and gradual movement of the catch and pawl, utilizing a gearbox or lever mechanism for efficient angle transmission and a pre-tensioned spring for enhanced braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pawl with a locking moment is used to ensure reliable ratcheting, then the locking reliability is improved, but opening noise increases due to abrupt acceleration of the catch and pawl
Solution Approach 1:
The brake latch is positioned to engage with the catch before the pawl is moved out of its ratchet position. This preliminary engagement creates a controlled braking action that prevents abrupt acceleration during opening, thereby reducing opening noise while maintaining locking reliability through the pawl's locking moment
Solution Approach 2:
The brake latch acts as an intermediary element between the catch and the pawl. By introducing this intermediate component that can independently engage and brake the catch, the system resolves the contradiction between maintaining reliable locking (through the pawl) and reducing opening noise (through the brake latch's controlled deceleration)
2Object-generated harmful factors
If the brake latch is positioned to brake the catch during opening, then opening noise is reduced, but the complexity of the locking mechanism increases
Solution Approach 1:
The brake latch is integrated into the existing locking mechanism structure, sharing the same rotational axis and housing as the pawl. This merging of functions allows the brake latch to perform its noise-reducing function without requiring a completely separate mechanism, thereby limiting the increase in complexity
Solution Approach 2:
The brake latch serves multiple functions: it acts as a braking surface for the catch during opening to reduce noise, and it can also serve as a structural component of the locking mechanism. This multi-functionality helps offset the added complexity by consolidating roles within existing components
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 opening noise and ensures reliable operation of the latch, capable of quiet opening and closing, even with a pawl having a locking moment, by using a small actuation movement to move the brake latch out of its braking position, thus minimizing noise and mechanical stress without increasing weight or cost.
Implementation Method 1
a spring which pre-tensions the brake latch in the direction of the braking position
Implementation Method 2
a towing arm mechanism with transmission that can lift the brake latch out of its braking position
Data Source
AI summary
The aim of the invention is to provide a locking mechanism for a lock, which can be opened quietly. To achieve this aim, a lock is proposed comprising a locking mechanism with a rotary latch, a locking pawl for locking the rotary latch in a detent position and a braking pawl which initially can brake a rotary motion of the rotary latch that occurs after or during a movement of the locking pawl out of its detent position. Opening sounds can be reduced by means of this initial braking action. The lock also comprises a driving dog mechanism with a translatory action that can lift the braking pawl out of its braking position. This ensures that the braking pawl is moved out of its braking position in a reliable manner so that the lock can be opened.