Motor Vehicle Door Lock Two-Part Pawl Noise Reduction

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Solution Overview

Problem

Existing motor vehicle door locks face issues with the pawl unintentionally interacting with the rotary latch during the closing process, leading to security problems and noise disturbances due to metal-to-metal contact.

Innovation Solution

A two-part pawl system with a base pawl and a cover pawl, where the base pawl is designed with a higher mass and primarily responsible for the locking mechanism, while the cover pawl, with a lower mass, prevents the base pawl from falling into the catch during slamming, and a noise-damping contour on the rotary latch reduces noise by minimizing metal-to-metal contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single pawl is used in the locking mechanism, then the structure is simple, but the pawl may unintentionally interact with the rotary latch during door closing, causing security problems

Engineering Contradiction:

Improvestructure simplicityVSAvoidlocking security

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The single pawl is divided into two separate pawls: a base pawl and a cover pawl. The base pawl is responsible for the primary locking function, while the cover pawl prevents unintended interaction during door closing. This segmentation allows each component to have a specialized function, improving reliability without significantly complicating the overall structure.

Inventive Principle:

Principle #1Segmentation

2Strength

If metal-to-metal contact is used in the locking mechanism, then the structure is simple and strong, but noise is generated during closing and opening processes

Engineering Contradiction:

Improvestructural strengthVSAvoidnoise

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The rotary latch is designed with a plastic coating on its outer circumference, creating a composite structure where a metal core provides structural strength and a plastic layer reduces noise during operation. This allows the locking mechanism to maintain its strength while minimizing harmful noise generation during door closing and opening.

Inventive Principle:

Principle #40Composite materials

3Reliability

If the pawl is held in the lifted position by a storage element during door closing, then unintended interaction is prevented, but the closing process becomes more complex

Engineering Contradiction:

Improveprevention of unintended interactionVSAvoidclosing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The cover pawl is designed to pass through a pre-ratchet position on the rotary latch during the closing process. This preliminary action ensures that the cover pawl is in the correct position before the base pawl engages with the main ratchet, preventing any unintended interaction during door closing without requiring complex control mechanisms.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentEP2712381B1Motor vehicle door lock

Publication Date: 2018.01.10 KIEKERT AG

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AI summary

The invention relates to a motor vehicle door lock comprising a ratchet mechanism (1, 2, 3) consisting substantially of a rotary latch (1) and a pawl (2, 3), and comprising a case (4) for housing the ratchet mechanism (2, 3). The pawl (2, 3) is designed in two parts with a first pawl element (2) and a second pawl element (3) that are movably interconnected.