Motor Vehicle Door Latch Rubber Buffer for Rattle Reduction

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Solution Overview

Problem

Motor vehicle door locks with locking levers often experience rattling noises due to play in the locking lever chain or drive, and there is a need for reliable definition and reproducibility of the 'unlocked' and 'locked' positions to prevent noise and ensure proper sensor queries.

Innovation Solution

A rubber-elastic buffer is integrated into the lock housing, acting as both a stop for the locking lever and an entry buffer for the locking bolt, providing cushioned end stops and ensuring the lever assumes correct positions without rattling, while allowing for accurate querying of the functional positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional stops are added to define locking lever positions, then position accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveposition accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into a single buffer element: it serves as both the stop defining the locked position and the inlet buffer for the locking bolt. This merging eliminates the need for separate stops while maintaining position accuracy, directly resolving the contradiction between position accuracy and device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The buffer is designed to perform multiple functions simultaneously: it acts as a position stop for the locking lever, an inlet buffer for the locking bolt, and a damping element. This multi-functionality achieves accurate position definition without adding device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If locking lever chain and drive are used to hold positions, then ease of operation is improved, but reliability deteriorates due to play causing rattling noises

Engineering Contradiction:
Improveease of operationVSAvoidreliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The rubber-elastic buffer provides beforehand cushioning by absorbing play and movements in the locking lever before they can cause rattling noises. The buffer's elastic properties dampen vibrations and ensure reliable position holding, resolving the reliability issue while maintaining ease of operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If multiple separate components are used for stops and buffers, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvemanufacturing precisionVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the stop function and inlet buffer function into a single integrated buffer component. This reduces the number of parts that need to be manufactured and assembled, lowering device complexity while maintaining manufacturing precision through the buffer's geometric design

Inventive Principle:
Principle #5Merging (Combining)

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 rattling noises and ensures the locking lever is correctly positioned and queryable, enhancing the noise behavior and reliability of the door lock's functional states.

Implementation Method 1

a rubber-elastic buffer (21), which is supported on a housing (1, 2)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the locking lever experiences a cushioned end stop in the two functional positions in question. As a result, the locking lever assumes the functional position in question without any problems and is at the same time damped in the relevant functional position with regard to any movements

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2499312B1Motor vehicle door latch
Publication Date: 2018.05.16 KIEKERT AG
  • EP2499312B1 patent drawingFigure 1
  • EP2499312B1 patent drawingFigure 2
  • EP2499312B1 patent drawingFigure 3

AI summary

The invention relates to a motor vehicle door latch, comprising a locking mechanism (3, 4), at least one locking lever (5), which assumes at least two different functional positions, for example "unlocked" and "locked", and at least one stop (17, 18), which defines the respective functional position, wherein the stop (17, 18) is formed on a rubber-elastic cushion (21), which is supported on a housing (1, 2).