Bistable Motor Vehicle Door Lock Lever Mechanism
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Solution Overview
Problem
Existing motor vehicle door lock mechanisms are susceptible to tolerances and cannot adequately prevent unwanted axial forces or adjust moments between end positions, leading to instability in locking and safety lever positions.
Innovation Solution
A bistable position securing unit composed of a torsion spring and a contour with convex formations and contact areas, which ensures the lever maintains two stable positions by generating a resultant force component that acts in opposite directions depending on the lever's position, and is connected to a drive element to limit and specify movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a torsion spring is used to act on the lever, then the lever can be actuated, but unwanted axial forces are introduced and moments in end positions cannot be adjusted sufficiently
Solution Approach 1:
The spring force is segmented into two separate spring legs that act independently on different formations of the contour. Each spring leg can be optimized for its specific function: one leg provides the main actuating force while the other leg compensates for axial forces and adjusts moments. This segmentation allows independent optimization of each spring leg's characteristics.
Solution Approach 2:
The contour with its spaced formations acts as an intermediary between the spring and the lever. The contour translates the spring forces into controlled moments and forces on the lever, enabling precise adjustment of end position moments and prevention of unwanted axial forces through its geometric design.
2Reliability
If the spring and contour are designed to provide stable positions, then position reliability improves, but the design complexity increases
Solution Approach 1:
The position securing function is merged into a compact arrangement where the torsion spring and contour with spaced formations work together as an integrated bistable mechanism. The two spring legs and two formations are combined in a space-efficient configuration that provides both stability and adjustability without requiring separate complex mechanisms.
Solution Approach 2:
The design allows for parameter adjustments in the spring legs (stiffness, preload) and contour formations (shape, position, spacing) to optimize the bistable characteristics. These parameter changes enable tuning of the end position moments and force characteristics without changing the fundamental structure.
3Measurement precision
If the spring legs continuously contact the formations in both end positions, then position precision improves, but manufacturing tolerances become more critical
Solution Approach 1:
The spring legs are designed to dynamically adapt their contact points with the formations based on the lever position. The continuous contact is maintained through the elastic deformation of the spring legs, which compensates for manufacturing tolerances and ensures reliable engagement in both end positions without requiring extremely tight tolerances.
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 a stable and cost-effective motor vehicle door lock that reliably maintains the 'lock on' and 'lock off' positions, compensates for design tolerances, and allows for adjustable pretension forces, enhancing safety and assembly simplicity.
Implementation Method 1
The spring is designed as a torsion spring with two spring legs. In fact, such a torsion spring usually not only has the two spring legs but also at least one spring coil, with the help of which the torsion spring is arranged either in or on the lock case or lock housing or on or on the lever and is supported thereon.
Data Source
Figure 1
Figure 2
AI summary
The present invention relates to a motor vehicle door lock, which is equipped with at least one lever (1), particularly a securing lever. In addition, a spring (2) that is associated with the lever (1) is provided. According to the invention, the spring (2) interacts with an associated contour (4) in order to form together a bistable position securing unit (2, 4).