Vehicle Door Lock Switching Mechanism Design
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Solution Overview
Problem
Existing vehicle door lock devices face challenges in design flexibility and mountability due to difficulties in adjusting the relative positional relationship between the switching mechanism and the pawl, leading to increased weight and complexity, which can result in unintended door opening during impacts.
Innovation Solution
A vehicle door lock device with a switching mechanism that includes a first lever, a second lever, an inertial lever, and a transmitting portion, where the inertial lever pivots from an initial position by an inertia force exceeding a preset value, preventing the transmission of pivotal movement to the second lever during impacts, thus maintaining the door in a latched state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the intermediate lever is elongated to reach the engaging claw portion that has changed position, then the engaging claw portion can be pressed by the intermediate lever, but the weight of the intermediate lever is excessively increased and it becomes difficult to set the inertia force
Solution Approach 1:
The switching mechanism is divided into two separate levers: the first lever connected to the door handle and the second lever acting on the pawl. This segmentation allows each lever to be optimized independently, preventing the need for an excessively long intermediate lever while maintaining the ability to accommodate various positional relationships through the coordinated movement of both levers around a common axial center.
Solution Approach 2:
The patent introduces a vertical dimension by having the inertial lever pivot about an axis extending in the vertical direction (orthogonal to the door's advance-retraction direction). This dimensional change allows the inertial lever to effectively block the transmitting portion without requiring horizontal extension, thus reducing the lever's weight while maintaining adaptability.
2Length of moving object
If the components are concentrated at the other end side of the outside lever to bring the intermediate lever closer to the engaging claw portion, then the intermediate lever can reach the engaging claw portion, but an installation space of the intermediate lever will be difficult to ensure
Solution Approach 1:
By segmenting the switching mechanism into two separate levers (first lever and second lever) that both pivot around a common axial center, the patent eliminates the need for a single long intermediate lever. This allows components to be distributed more compactly in the horizontal plane while maintaining the necessary functional reach through the coordinated action of both levers.
Solution Approach 2:
The patent merges the pivot centers of the first lever and second lever into a single common axial center. This consolidation allows both levers to operate within a compact space, reducing the overall installation area required while ensuring sufficient space for the inertial lever's vertical pivoting motion.
3Reliability
If the inertial lever's weight is increased to ensure it pivots from the initial position by inertia force during impact, then the door remains latched during impact, but the weight and complexity of the device is increased
Solution Approach 1:
The patent concentrates the inertial mass locally in the inertial lever that pivots vertically, rather than distributing weight throughout the entire switching mechanism. This localized mass concentration provides sufficient inertia force to block the transmitting portion during impact while keeping the overall device weight low. The local quality of the inertial lever is optimized to provide the necessary inertia without excessive weight.
Solution Approach 2:
The patent changes the pivotal parameter from horizontal movement (requiring heavy levers) to vertical movement (requiring minimal mass). By having the inertial lever pivot about a vertical axis rather than requiring horizontal extension, the system achieves reliable inertia-based blocking with minimal weight. The parameter change from horizontal to vertical pivoting dramatically reduces the weight required while maintaining reliability.
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
This configuration enhances design flexibility, reduces the size of the device, and improves mountability while ensuring passenger safety by preventing unintentional door opening during impacts without increasing the inertial lever's weight or complexity.
Implementation Method 1
an inertial lever provided on one of the first lever and the second lever, being pivotable about an axis extending in a direction orthogonal to the direction of advance and retraction with respect to the opening, and that pivots from an initial position about the axis by application of an inertia force exceeding a preset value
Data Source
AI summary
A switching mechanism of vehicle door lock device includes a pivotable first lever and a second lever that pivotably acts on a pawl. An inertial lever is provided on the first lever and is pivotable about an axis (X3) from an initial position when an inertial force is applied thereto. A transmitting portion is provided on the second lever and transmits the pivotal movement of the first lever to the second lever when the inertial lever is disposed in its initial position. In contrast, the transmitting portion does not transmit the pivotal movement of the first lever to the second lever when the inertial lever has been pivoted away from its initial position. A first axial center of pivotal movement of the first lever and a second axial center of pivotal movement of the second lever are coaxial axial centers of pivotal movement (X1).