JPH038972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an on-vehicle detonator that prevents erroneous abnormality detection due to voltage fluctuations of an on-vehicle power source.

BACKGROUND ART In order to protect the occupants of a passenger car or the like from impact during a collision, a passenger car equipped with an occupant protection device has been proposed, which is equipped with a gas-inflatable cushion near the driver's seat or other seats. Generally, this type of occupant protection device has a gas generator containing a current-operated explosive, and the shock at the time of a collision detonates the gas generator to generate gas, which drives the cushion in front of the occupant. It is designed to be inflated and cushioned.
By the way, the detonator called a squib built into the detonator is designed to ignite when a current exceeding a certain level is passed through, but it is as if the wire had not been disconnected before the collision, so it is difficult to ensure reliable operation in the event of a collision. An anomaly detection circuit may be added to ensure this.

FIG. 1 is a schematic configuration diagram showing an example of a conventional vehicle-mounted detonator equipped with an abnormality detection circuit. The on-vehicle detonator 1 shown in the figure is a gas-expandable cushion 2a.
Both ends of the detonator 3 in the gas generator 2 are connected to the on-vehicle power source 6 via shock sensors 4 and 5, and the potential difference generated at both ends of the detonator 3 due to a minute current below the ignition current that constantly flows through the detonator 3 is It was configured to be monitored by a potentiometer in the abnormality detection circuit 7. However, the switch S that closes due to the impact shock
The impact sensors 4 and 5, which are connected in parallel to the resistor R, are
Since the resistance value of the resistor R was sufficiently large compared to the resistance R ₀ of the detonator 3 itself, the potential difference generated between both ends of the detonator 3 was an extremely small value.

Therefore, when the voltage of the in-vehicle power supply 6 fluctuates rapidly, such as when the engine is in use or when the headlights are turned on, the potential difference between the two ends of the detonator 3 also tends to fluctuate, which may cause the abnormality detection circuit 7 itself to malfunction. There were flaws.

In addition, especially when a comparison circuit (not shown) for comparing the output of a potentiometer provided in the abnormality detection circuit 7 with a reference value is operated by a stabilized power supply, There were drawbacks such as voltage fluctuations easily appearing as abnormality detection.

DISCLOSURE OF THE INVENTION This invention eliminates the above drawbacks,
An abnormality detection circuit that connects a dummy resistor circuit with the same resistance value in parallel to the detonator circuit and compares the current values of both circuits to accurately detect abnormalities such as disconnections and short circuits in the detonator circuit. The purpose is to provide a vehicle-mounted detonator with a

To achieve this objective, the present invention has a detonator circuit in which a detonator that ignites when a current exceeds a certain value is connected in series to an impact sensor whose resistance value changes when it detects an impact applied to the vehicle. In a vehicle-mounted detonator configured such that a gas generator connected to a gas-expandable cushion is detonated by ignition of the detonator, a dummy circuit having the same resistance value as the detonator circuit and connected in parallel to the detonator circuit; The gist of the present invention is to provide an abnormality detection circuit that compares the current flowing through the dummy circuit and the detonator circuit, and determines that an abnormality exists when the current values do not match.

According to this invention, a dummy circuit with an equal resistance value is connected in parallel to a detonator circuit in which a shock sensor whose resistance value changes when it senses an impact is connected in series with a current-activated detonator, and the value of the current flowing through both circuits is connected in parallel. As a result of the comparison, since the configuration is designed to detect abnormalities such as disconnections or short circuits that occur in the detonator circuit during normal conditions, abnormalities in the detonator circuit can be accurately detected regardless of voltage fluctuations in the on-board power supply connected to the detonator circuit and the dummy circuit. Unlike conventional in-vehicle detonators, which detect abnormalities in the detonator from the potential difference between the two ends of the detonator, false detections do not occur due to voltage fluctuations in the on-vehicle power supply. It has excellent effects such as being able to ignite and detonate.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to FIG. FIG. 2 is a schematic diagram showing an embodiment of the on-vehicle detonator of the present invention. In addition,
In FIG. 2, the same components as in FIG. 1 are given the same reference numerals.

In FIG. 2, the on-vehicle detonator 11 includes a detonator circuit 12 which is a series connection circuit of a detonator 3 and impact sensors 4 and 5.
For this, a dummy circuit 13 equivalent to this is prepared,
A current detection circuit 12 is provided in both circuits 12 and 13, respectively.
a, 13a are connected in parallel to the on-vehicle power source 6. The dummy circuit 13 is
Two resistors r having the same resistance value as the resistor R and a resistor r ₀ having the same resistance value as the detonator 3 are connected in series.

The outputs of both current detection circuits 12a and 13a are supplied to the reference input terminal and comparison input terminal of two comparison circuits 14 and 15, respectively, and the comparison circuits 14 and 15 perform difference calculations with opposite polarities. The outputs of these comparison circuits 14 and 15 are supplied to an OR gate circuit 16, and the alarm lamp 17 is turned on by the transistor Q which is made conductive by the output of the OR gate circuit 16.

In the case of this embodiment, current detection circuits 12a, 13a
The comparator circuits 14 and 15, the OR gate circuit 16, the alarm lamp 17, and the like constitute an abnormality detection circuit 18.

Now, if there is no disconnection or short circuit in the detonator circuit 12, the resistance values of the detonator circuit 12 and the dummy circuit 13 are the same, and of course the current values flowing through both circuits 12 and 13 are also the same.Therefore, the comparison circuit 14, 15 are both in a state of zero output, and the abnormality detection circuit 18 does not operate.

On the other hand, if a break occurs in the detonator circuit 12, no current will flow through the detonator circuit 12, so the output of the comparator circuit 14 is supplied to the OR gate circuit 16, and as the transistor Q becomes conductive, the alarm lamp 17 lights up, indicating that there is an abnormality. Detected. Furthermore, when a short circuit occurs in the detonator circuit 12, the current value flowing through the detonator circuit 12 exceeds the current value flowing through the dummy circuit 13, so the alarm lamp 17 lights up due to the output of the comparison circuit 15, and an abnormality is detected. be done.

In this way, the on-vehicle detonator 11 has a detonator circuit 1
Since the configuration is such that an abnormality in the in-vehicle power supply 2 is detected by comparing the current with the dummy circuit 13, an abnormality can always be accurately detected regardless of voltage fluctuations of the on-vehicle power supply 6. Furthermore, by connecting an alarm means such as an alarm lamp 17 or a buzzer to each of the comparison circuits 14 and 15, it is possible to immediately detect whether an abnormality is caused by a disconnection or a short circuit. . Furthermore, by connecting a bias circuit or the like to the reference input sides of the comparison circuits 14 and 15, it is also possible to arbitrarily set an allowable value for the difference between the current values to be compared.

As explained above, according to the on-vehicle detonator 11, the shock sensors 4 and 5 whose resistance value changes when an impact is detected are connected in series to the current-operated detonator 3. circuit 13
are connected in parallel and the current value flowing through both circuits 12 and 13 is compared to detect an abnormality such as a disconnection or short circuit that occurs in the detonator circuit 12 under normal conditions. It is possible to accurately detect an abnormality in the detonator circuit 12 regardless of the voltage fluctuation of the on-board power supply 6 caused by the on-board power supply 6. Erroneous detection does not occur due to voltage fluctuations, and as a result, the detonator 3 can be reliably ignited and detonated when an impact occurs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional vehicle-mounted detonator, and FIG. 2 is a schematic diagram showing an embodiment of the vehicle-mounted detonator of the present invention. 2...Gas generator, 2a...Gas expansion type cushion, 3...Detonator, 11...Vehicle-mounted detonator, 1
2...Detonator circuit, 13...Dummy circuit, 12a,
13a... Current detection circuit, 14, 15... Comparison circuit, 16... OR gate circuit, 17... Warning lamp, 18... Abnormality detection circuit.

Claims (1)

[Claims] 1. A gas generator that has a detonator circuit in which a detonator that ignites when a current exceeds a certain value is connected in series to an impact sensor whose resistance value changes when it detects an impact on the vehicle, and is connected to a gas-inflatable cushion for passenger protection. In a vehicle-mounted detonator configured to be activated by ignition of the detonator, the device includes a dummy circuit having the same resistance as the detonator circuit and connected in parallel to the detonator circuit; An on-vehicle detonator equipped with an abnormality detection circuit that compares current values and determines that there is an abnormality when the current values do not match.