Motor Vehicle Lock Sensing for Reliable Pawl and Latch Detection
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Solution Overview
Problem
Existing motor vehicle door locks face issues with functional reliability due to temperature and aging effects, particularly affecting the sensing of the rotary latch and pawl positions, leading to malfunctions in detecting the locking mechanism's status.
Innovation Solution
A motor vehicle door lock design featuring a multi-arm lever with a rotatable sensing element, equipped with pawl and rotary latch contours, preloaded by a stationary spring, allowing it to assume two distinct positions based on the locking components' states, ensuring reliable detection of both the rotary latch and pawl positions using a single sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an elastically adjustable actuating element (bending beam) is used to sense both rotary latch and pawl positions, then a single sensor can detect both positions, but the sensing reliability deteriorates due to temperature and aging effects on the metal or plastic strip
Solution Approach 1:
The sensing element is divided into two separate rotatable sensing elements, each independently mounted on the lock case. Each sensing element has its own spring and sensor, eliminating the coupling between rotary latch and pawl sensing that causes reliability issues in temperature-vulnerable bending beam designs.
Solution Approach 2:
A rotatable sensing element with a cam profile acts as an intermediary between the locking mechanism components (rotary latch and pawl) and the sensor. The cam profile translates the positional states of the locking components into distinct rotational positions of the sensing element, enabling reliable detection without direct mechanical coupling.
2Loss of information
If multiple switches are used to detect functional positions of closing lever, rotary latch, and pawl, then comprehensive position information is obtained, but the design and circuitry complexity increases considerably
Solution Approach 1:
Multiple sensing functions (detecting rotary latch position and pawl position) are merged into a single rotatable sensing element structure. The cam profile on the sensing element simultaneously interacts with both the rotary latch and pawl, allowing one sensor to capture both positional states without requiring multiple separate switches and their associated circuitry.
Solution Approach 2:
The rotatable sensing element serves multiple functions: it detects the rotary latch position through its cam profile interaction, detects the pawl position through the same rotational movement, and provides a unified mechanical interface for a single sensor. This multi-functionality eliminates the need for multiple specialized switches.
3Measurement precision
If a pushbutton element with an arm is used to actuate a switch, then the rotary latch position can be detected, but additional position sensing of the pawl is not possible
Solution Approach 1:
The sensing element uses a cam profile that extends in multiple directions, allowing it to interact with both the rotary latch and the pawl simultaneously. By adding dimensional complexity to the cam profile shape rather than adding more sensing elements, the system achieves versatile position detection capability.
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 design enhances functional reliability by reliably detecting any deviation from the closed position of the locking components, unaffected by temperature and aging effects, and provides comprehensive information about the locking mechanism's status.
Implementation Method 1
the sensing element is pretensioned in the direction of the locking mechanism by means of a spring
Data Source
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AI summary
The invention relates to a motor vehicle lock, and in particular a motor vehicle door lock, which is equipped with: a locking mechanism (1, 2) consisting substantially of the locking mechanism components (1, 2) of a rotary latch (1) and a pawl (2); at least one sensor (3) for sensing the position of the rotary latch (1) and the pawl (2); and at least one sensing element (5) between the sensor (3) and the associated locking mechanism component (1, 2). The sensing element (5) has a pawl contour (6) and a rotary latch contour (7) for sensing a closed position of the pawl (2) on the one hand and the rotary latch (1) on the other hand. Furthermore, the sensing element (5) is designed to be rotatable relative to an axis. In addition, the sensing element (5) is prestressed in the direction of the locking mechanism (1, 2) by means of a spring (9). According to the invention, the spring (9) is designed to be stationary and is equipped with a spread-apart spring arm (9b) which acts on the sensing element (5).