Vehicle Door Lock Inertial Lever Mechanism
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Solution Overview
Problem
Existing vehicle door lock devices face challenges in reliably preventing door opening during impacts, as they often fail to achieve the 'swing-and-miss state' due to limited pivot angles of the switching lever, which can result in unintended door opening and compromised occupant safety.
Innovation Solution
A vehicle door lock device featuring a switching lever with an inertial lever and a torsion coil spring biasing member, allowing the inertial lever to pivot freely beyond the initial position without being limited by the lever main body, ensuring the 'swing-and-miss state' is achieved even under excessive impacts, thus preventing unintentional door opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the switching lever uses an engagement hole and engagement claw portion structure to limit pivot angle, then the door opening operation is controlled precisely, but the pivot angle becomes insufficient to achieve swing-and-miss state under excessive impact
Solution Approach 1:
The switching lever is divided into two independent parts: the lever main body and the inertial lever. The lever main body is connected to the door handle and transmits opening operations, while the inertial lever responds independently to impact forces. This segmentation allows each part to perform its specific function without interfering with the other, enabling the inertial lever to pivot freely to achieve swing-and-miss state while the lever main body maintains controlled door opening operation.
2Ease of operation
If the coil springs are used to bias the switching lever, then the normal door opening operation is facilitated, but the pivot angle is limited by the spring expansion range
Solution Approach 1:
The biasing function is segmented between two independent components: coil springs connected to the lever main body for normal operation, and a mass body connected to the inertial lever for impact response. The coil springs provide smooth biasing force for normal door opening operations, while the mass body provides inertial resistance to impact forces. This segmentation allows each component to operate within its optimal range without limiting the other's pivot angle.
Solution Approach 2:
The mass body acts as a counterweight to the coil springs, providing inertial resistance to impact forces. When impact occurs, the mass body resists acceleration according to Newton's second law (F=ma), creating a counteracting force that prevents the switching lever from pivoting excessively. This counterweight mechanism enables the inertial lever to pivot freely in the opposite direction to achieve swing-and-miss state while maintaining controlled normal operation.
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 enhances occupant safety by reliably preventing door opening during impacts, allowing for a wider pivot angle of the inertial lever, which is not limited by the lever main body or biasing member, thereby ensuring the 'swing-and-miss state' is maintained, even under large impacts.
Implementation Method 1
a biasing member having a biasing force that retains the inertial lever in the initial position... the biasing member and the mass body are set such that if an inertial force greater than a pre-determined value acts on the mass body, the inertial lever pivots from the initial position
Implementation Method 2
if an inertial force greater than a pre-determined value acts on the mass body, the inertial lever pivots from the initial position about the pivot relative to the lever main body... the switching lever will compress one of the coil springs and expand the other coil spring to pivot towards the opposite direction of the direction of the impact
Data Source
AI summary
A switching lever of a vehicle door lock device includes a lever main body, an inertial lever having a mass body pivotably disposed on the lever main body so as to be pivotable from its initial position about a pivot, and a torsion coil spring disposed between the lever main body and the inertial lever and biasing the inertial lever towards its initial position. If the inertial lever is disposed in its initial position and is displaced integrally with the lever main body, the inertial lever will press a pawl, thereby causing a fork to switch to an unlocked position. However, if an inertial force greater than a pre-determined value acts on the mass body, the inertial lever will pivot from its initial position in a direction opposite of the interial force and avoid pressing the pawl, such that the fork is maintained in a locked state.