Vehicle Safety Sensor With Magnetic Inertia-Body Deactivation
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Solution Overview
Problem
Existing vehicle safety sensors in belt retractors can be triggered undesirably due to movements such as pivoting or reclining of vehicle seats, leading to erroneous activation of safety devices.
Innovation Solution
A sensor system with a deactivation device that uses a magnetic field to maintain the inertia body in its inoperative position, and an activation device that allows mechanical triggering, enabling dual triggering mechanisms and reducing part complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor operates purely on inertia without additional control mechanisms, then the device complexity is reduced, but the sensor triggers erroneously during seat movements such as pivoting or reclining
Solution Approach 1:
The deactivation device is activated in advance before seat movement occurs to prevent the inertia body from triggering the sensor during normal seat pivoting or reclining operations. This preliminary action ensures the sensor remains inoperative during these movements, preventing erroneous triggering while maintaining simplicity.
Solution Approach 2:
The sensor system transitions from a static inertia-based design to a dynamic system where the deactivation device can actively control the inertia body's position. This dynamic control allows the sensor to adapt between operative and inoperative states based on seat movement conditions, improving reliability without excessive complexity.
2Reliability
If the deactivation device uses a magnetic field to hold the inertia body, then the reliability of preventing false triggering is improved, but the use of energy increases due to the magnetic field generating device
Solution Approach 1:
The magnetic field generating device operates periodically or intermittently rather than continuously, activating only when seat movement is detected or anticipated. This periodic operation maintains reliable prevention of false triggering while significantly reducing overall energy consumption compared to continuous magnetic field generation.
3Adaptability or versatility
If the sensor includes both deactivation and activation devices, then the versatility of the sensor is improved, but the device complexity increases
Solution Approach 1:
The inertia body serves multiple functions: it acts as both the sensing element for inertia-based triggering and as a controllable element for both deactivation (via magnetic field) and activation (via mechanical pushing). This multi-functionality reduces the need for separate components, achieving versatility without excessive complexity.
Solution Approach 2:
The deactivation device (magnetic field generator) and activation device (mechanical pusher) are integrated into a unified sensor system that shares common structural elements. The inertia body itself is the target for both deactivation and activation actions, merging multiple functions into a cohesive design that balances versatility and complexity.
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
Prevents unnecessary triggering of vehicle safety devices during seat movements while ensuring reliable operation through both inertia and external mechanical activation.
Implementation Method 1
the deactivation device comprises a magnetic field generating device which, in the deactivating state of the deactivation device, generates a magnetic field which pulls the inertia body into its inoperative position and/or holds it there
Implementation Method 2
the inertia body is composed at least in sections of a magnetizable material
Implementation Method 3
The magnetic field generating device preferably comprises a coil which, when current flows through it, generates the magnetic field
Implementation Method 4
an electromagnet
Data Source
AI summary
The invention relates to a sensor (310), in particular for triggering a vehicle safety device (301), having a movable inertia body (350) which is movable relative to a carrier element (340) of the sensor (310), wherein the inertia body (350) is moved by inertia in relation to the carrier element (340) in the event of an abrupt change in speed or an inclination of the sensor (310) beyond a predetermined extent, and is brought from its inoperative position into its triggering position, through which a triggering position of the sensor (310) is brought about.According to the invention, it is provided that the sensor (310) is provided with a deactivation device (700) which is suitable, in its deactivating state, to force the inoperative position of the inertia body (350).