Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2003-02-06
2004-02-17
La, Anh (Department: 2636)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S436000, C340S590000, C307S010100, C200SDIG009, C180S274000
Reexamination Certificate
active
06693549
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a sensor system, particularly for detecting mechanical forces which, for example, during a collision of a motor vehicle with an obstacle, may lead to an intrusion or deformation of components on this motor vehicle.
BACKGROUND INFORMATION
Such sensor systems may be used, for example, for so-called occupant-restraint systems in motor vehicles which, for instance, trigger airbags in response to accidents to protect the vehicle occupants from the results of a collision. For triggering these occupant-restraint systems, for example, the acceleration in the passenger compartment or at peripheral regions of the motor vehicle is measured. In addition to the sensor or sensors in the passenger compartment, the peripheral sensors may be, as a rule, installed at the deformable areas of the vehicle. Thus, for example, for better and early. recognition of lateral collisions, acceleration sensors may be installed on the so-called B-pillar and/or C-pillar of the vehicle, or on the seat crossmembers below the front seat.
In comparable manner, for better recognition of head-on crashes, sensors which likewise may measure the acceleration and convert the measured values into corresponding, electronically evaluable signals to better determine the severity of a crash may also be built into the front crash crumple zone of the vehicle.
Particularly in the case of lateral collisions, conventional acceleration sensors may permit rapid detection of a crash only if the sensor is directly struck. Thus, for example, when installed on the B-pillar, a fixed-pole crash into the door of the vehicle may be recognized too late. By themselves, pressure sensors may also cause problems with respect to a separation of the triggering and non-triggering conditions when installed at these locations, since they may be configured not to respond, for instance, to heavy door slamming. In the case of a triggering of driver and front-seat passenger airbags, as well, these pressure sensors may be configured not to interpret the pressure rise in the passenger compartment as deformation of the door.
Furthermore, in the case of a collision, the velocity of the intrusion by the obstacle may also be a decisive factor which determines the severity of the accident and the danger of injury for the occupants. In this context, the intrusion velocity may be linked to the width of the obstacle and the location of the impact. For example, a post having a small surface may intrude very deeply and quickly, while a wide barrier which impacts on the vehicle with the same velocity may intrude more slowly and not as deeply. If the post strikes the middle of the door, it may penetrate considerably more quickly than if it strikes on the B-pillar. The wider an obstacle is, the more slowly it may penetrate, and the softer the location of the impact, the deeper and more quickly it may penetrate.
German Published Patent Application No. 22 12 190 describes a sensor system in which deformation forces may be detected with, the aid of contact elements which may be arranged one after the other in a deformation direction. From this, the intrusion velocity may be determined. A contact between the contact elements may be effected by deformation of an elastic intermediate layer. U.S. Pat. No. 3,717,735 describes the construction of deformation sensors in such a manner that a closed contact may be opened in response to a deformation. U.S. Pat. No. 2,938,977 describes a contact configuration which may be provided with an intermediate layer on one side or both sides in partial areas.
SUMMARY OF THE INVENTION
A sensor system for detecting forces which may lead to a deformation of mechanical components, e.g., on motor vehicles, may provide for a number of contact elements chiefly on the possibly deformed components which may be arranged staggered one behind the other in a possible deformation direction.
Insulation layers, which may be compressible by the deformation of the component, may be disposed between the contact elements. The contact elements may be electroconductively connected to an electronic evaluation circuit by which a contacting and/or de-contacting of adjacent contact elements, caused by the deformation, may then be able to be detected and converted into control and/or regulating signals.
In a sensor system according to an example embodiment of the present invention, one contact element may represent a base element, and at least two contact elements may be positioned in front of it at predefined distances. The distances, i.e. the geometric configuration, and the material for these two compressible insulation layers may in each case be selected so that the intrusion velocity of the object causing the deformation may be able to be derived from the moments of the contacting and/or de-contacting of the contact elements situated one behind the other in the deformation direction.
In the present invention, a compressible insulation layer made, for example, of foamed plastic, between the contact elements may have the function of correctly defining the geometrical spacings of the contact elements. Therefore, the compression properties of the material, in the same manner as the temperature characteristic and the stiffness, may not be critical. In constructing the sensor system, care may only be required to be taken that the stiffness does not become so high over the course of the service life of the sensor system that compression of the sensor system is prevented. In some application cases, the deformation forces occurring may be so considerable that an evaluable deformation may already be ensured by them alone, even if the stiffness of the sensor system should vary.
The present invention may permit the construction of a so-called intrusion sensor for a motor vehicle which, in response to an accident, may detect in a simple manner the penetration of an obstacle into the components of the vehicle and, in so doing, may allow determination of both the velocity of the intrusion and the width of the impacting object, as well as the location of the intrusion. The intrusion sensor itself may be deformed by the penetration, and the deformation may be utilized to bring the contact elements in contact with one another. The deformation itself may also be utilized for determining the severity of the crash. Moreover, the intrusion sensor itself may be utilized as a structural element in such a manner that the deformation characteristic of the vehicle may be influenced.
In addition to the lateral placement, such an intrusion sensor may also be used for detecting head-on collisions or rear collisions. For example, it may then be mounted on the bumper between the bumper and the plastic cladding. In one such configuration, the sensor may measure the relative velocity of the crash, and the width of the obstacle and the location of the impact may again be determined. For example, using this intrusion sensor, information about the impacting obstacle may be obtained as well.
The signals generated by the contact elements may be evaluated in a simple manner by connecting the contact elements, e.g., via an RC circuit, directly to a microprocessor of the electronic evaluation circuit, the microprocessor being able to directly measure the moments, e.g. T
1
and T
2
, mentioned above. However, moments T
1
and T
2
may also be determined by charging a capacitor, and sent as coded information directly to an analyzing unit, e.g. an airbag control unit in a motor vehicle.
For the contact elements to come reliably in contact, the sensor system may be required to be significantly deformed. Misuse conditions such as hammer blows and striking the door may as a rule not deform the sensor to the extent that both contact elements are closed. The misuse problems, which may be to some extent very serious for the conventional acceleration or pressure sensors, may be substantially prevented by the present invention. If, for example, the sensor is structurally mounted near a reinforcement tube in the door of a motor vehicle, then the safety with
Kenyon & Kenyon
La Anh
Robert & Bosch GmbH
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