Motor Vehicle Door Lock Sensing for Latch Position Detection

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Solution Overview

Problem

Existing motor vehicle door locks face challenges in reliably detecting the main locking position of the rotary latch and pawl, particularly under varying environmental conditions, due to complex interactions between the sensing element and spring geometry, which can lead to functional impairments.

Innovation Solution

A spring-loaded sensing element with a two-armed lever design, featuring a pawl lever arm and a rotary latch lever arm, is used to detect the pawl and rotary latch positions, utilizing a torsion spring with legs interacting with the rotary latch and housing stop, and a guide slot to ensure reliable detection of the main closed position, independent of environmental factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex spring geometry is used to ensure reliable detection under varying environmental conditions, then detection reliability is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoidspring geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring is divided into distinct functional segments: a body portion that engages the sensing element and leg portions that interact with the rotary latch. This segmentation allows each part to be optimized independently, simplifying the overall design while maintaining detection reliability across environmental variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring serves multiple functions simultaneously: it provides the actuating force for the sensing element, maintains contact with the rotary latch during rotation, and compensates for positional deviations. This multi-functionality eliminates the need for separate components, reducing complexity while ensuring reliable operation.

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

2Measurement precision

If multiple switches are used to monitor different locking component positions, then measurement precision is improved, but device complexity and circuitry effort increase

Engineering Contradiction:
Improveposition detection precisionVSAvoidswitch quantity and circuitry
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensing element combines multiple sensing functions into a single integrated component. It simultaneously detects the position of both the rotary latch and pawl through its interaction with their respective contours, eliminating the need for separate switches and reducing circuitry complexity while maintaining precise position detection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensing element acts as a universal detector for multiple locking components. By incorporating both a rotary latch contour and a pawl contour on its surface, a single element performs the work of multiple switches, reducing system complexity while preserving measurement precision for all locking positions.

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

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 reliable detection of the main closed position of the locking mechanism, maintaining functional reliability over time, regardless of temperature or humidity, without requiring specific spring geometries, and simplifies the design by using injection-molded plastic parts.

Implementation Method 1

at least one spring-loaded sensing element between the sensor and the associated locking component

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP4416357B1Motor vehicle lock, in particular motor vehicle door lock
Publication Date: 2025.10.29 KIEKERT AG
  • EP4416357B1 patent drawingFigure 1
  • EP4416357B1 patent drawingFigure 2
  • EP4416357B1 patent drawingFigure 3

AI summary

The invention relates to a motor vehicle lock, in particular a motor vehicle door lock, the basic construction of which is equipped with a locking mechanism (2, 3) consisting essentially of a rotary latch (2) and a pawl (3) as locking mechanism components (2, 3). Moreover, at least one sensor (5, 6) for sensing the position of the rotary latch (2) and the pawl (3) is implemented. Furthermore, at least one contact element (7), which is biased by a spring (10), is implemented between the sensor (5, 6) and the associated locking mechanism component (2, 3). The contact element (7) is designed to rotate about an axis (9). According to the invention, the spring (10) is mounted on the contact element (7) and is equipped with limbs (10b, 10c) on both sides for an interaction with the rotary latch (2) and a housing stop (11).