JPH10157560A - Airbag control device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide an airbag control device that has a plurality of inflators and selectively supplies current to two or more electric wires to a squib that operates each of the plurality of inflators. . SOLUTION: A plurality of squibs 2 each having a plurality of inflators and operating each of the plurality of inflators.
In an airbag control device for controlling the operation of an airbag device having 6a, 26b, 26c, power supplies 14, 16
From the plurality of squibs 26a, 26b, 26
c is supplied by two electric wires 40a, 40b, and the plurality of squibs 26a, 26b, 26c are connected in parallel, respectively, so that the plurality of squibs 26a, 26b are connected.
There is provided a supply current value control means for controlling so that currents having different current values are supplied to b and 26c, and selectively activate only a desired squib.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag control device for controlling the operation of an airbag device having a plurality of inflators and a squib for operating each of the plurality of inflators.

[0002]

2. Description of the Related Art Conventionally, airbag devices have been disclosed in
As disclosed in Japanese Patent No. 257315, there is an airbag device having a plurality of inflators and a squib for operating each of the plurality of inflators.

In this airbag device, electric wires for supplying current to each squib are separately provided for each squib, and the current is supplied to each squib at a staggered time via each electric wire. By supplying and sequentially operating each inflator, occupant protection in the event of a vehicle collision is effectively performed.

[0004]

However, in this airbag device, since electric wires for supplying current to each squib are separately provided for each squib, a large installation space is required for installing the electric wires. In addition to this, there is a problem that a long wire is required and the cost increases.

An object of the present invention is to provide an airbag control device which has a plurality of inflators and which can selectively supply a current to the squib for operating each of the plurality of inflators by using two electric wires. That is.

[0006]

The airbag control device according to the first aspect has a plurality of inflators, and controls the operation of the airbag device having a plurality of squibs for operating each of the plurality of inflators. In the bag control device, a current is supplied from a power supply to the plurality of squibs with two electric wires, and the plurality of squibs are connected in parallel, and currents having different current values are supplied to the plurality of squibs. The supply current value control means for controlling the squib is selectively operated.

Therefore, according to this airbag control device, it is possible to supply a current to a plurality of squibs with two electric wires, and by changing the current value of the supplied current, it is possible to supply a desired current among the plurality of squibs. Can be selectively activated.

According to a second aspect of the present invention, the supply current value control means of the airbag control device according to the first aspect is characterized in that the plurality of squibs have different current values due to an impact applied to a vehicle. Is supplied.

Therefore, according to the airbag control device, a desired squib can be selectively operated in response to an impact applied to the vehicle.

According to a third aspect of the present invention, in the airbag control apparatus of the first aspect, the supply current value control means further includes a resistor for at least one of the plurality of squibs. By connecting in series, a current having a different current value is supplied to each of the plurality of squibs.

Therefore, according to this airbag control device, the current flowing through one squib can be made smaller than the current flowing through the other squibs by connecting the resistor in series with the squib. Therefore, a desired squib can be selectively operated with a simple configuration.

The airbag control device according to a fourth aspect is characterized in that the plurality of inflators of the airbag control device according to the first to third aspects are constituted by three or more inflators.

Therefore, according to the airbag control device, three or more inflators can be selectively operated.

According to a fifth aspect of the present invention, in the airbag control apparatus according to the first or second aspect, the supply current value control means continuously supplies a current value to be supplied to the plurality of squibs. It is characterized by changing to.

Therefore, according to this airbag control device, it is possible to reduce a wasteful current as compared with a case where a constant current is always supplied to a plurality of squibs.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An airbag control device according to an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram of the airbag control device. In the figure, what is indicated by reference numeral 10 is DC-DC
The DC-DC converter 10 is connected to a DC power supply 14 via a switch 12 that is turned on when an ignition key (not shown) is turned on.

Here, the DC-DC converter 10 boosts the voltage when the voltage of the DC power supply 14 decreases,
This is for ensuring the airbag deployment performance when the voltage of the DC power supply 14 drops.

The backup power supply 16 has a backup capacitor (not shown), and the backup capacitor is always kept charged by the DC-DC converter 10. The backup power supply 16 supplies an ignition current to a squib described later by discharging the electric charge stored in the backup capacitor when the electric wiring or the like is disconnected at the time of a vehicle collision and the supply of current from the DC power supply 14 is stopped.

The safing sensor 18 is a mechanical sensor comprising a roller, a plate spring, a stopper, and the like. When a deceleration exceeding a set value is applied, a rotating contact provided on the roller comes into contact with a fixed contact, and The current from the power supply 14 or the backup power supply 16 is supplied to the current control circuit 20.

The G sensor 22 is a ceramic sensor using a piezo element, detects the deceleration of the vehicle, and outputs a detection signal to the microcomputer 24.

The microcomputer 24 includes the G sensor 2
2 is provided with an A / D converter 24a for converting an analog signal corresponding to the detected deceleration output from 2 into a digital signal, and based on the digital data converted by the A / D converter 24a, The magnitude of the impact at the time of the collision is calculated, and a control signal corresponding to the calculation result is supplied to the current control circuit 2.
Output to 0.

The current control circuit 20 is a circuit for supplying a current having a current value corresponding to the control signal output from the microcomputer 24 to the squibs 26a, 26b, 26c. The current control circuit 20 includes two electric wires 4
The squibs 26a, 26b, and 26c are connected in parallel to the squibs 26a and 26b.
6b, the resistance R1, the squib 26b and the squib 26
and a resistor R2 is connected between the resistor R2 and the resistor c. Also,
Current bypass resistors R3 and R4 are connected to squibs 26a and 26a.
6b and 26c are connected in parallel.

The CPU monitor 28 monitors the operation status of the microcomputer 24, and outputs a control signal to the lamp drive circuit 30 when an abnormality is detected, turns on the indicator lamp 32 and sends the control signal to the current control circuit 20. And interrupts the supply of current to the squibs 26a, 26b, 26c.

The 5V power supply 34 is a power supply for driving the G sensor 22, the microcomputer 24, and the CPU monitor 28.

The above-mentioned current control circuit is specifically the circuit shown in FIG. 2, and is composed of an output gain variable amplifier 42 and a constant current circuit 44.

Here, the variable output gain amplifier 42 corresponds to FIG.
Has the output characteristics shown in FIG. That is, when the voltage signal input from the input terminal is small, the output gain variable amplifier 42
It is not operating and the output characteristics are determined by the resistance value of the resistor R40. As the voltage signal input from the input terminal increases, first, the transistor Tr3 is driven, and the transistor Tr3 draws a current limited by the emitter resistance of the transistor Tr3 and apparently decreases the output gain (see FIG. 3). Inflection point 1).

When the voltage signal input from the input terminal further increases, the transistors Tr2 and Tr1 are sequentially driven, and each of the transistors Tr2 and Tr1 draws the current limited by the emitter resistance and apparently decreases the output gain (FIG. 3). Inflection point 2 and inflection point 3).

Therefore, according to the variable output gain amplifier 42, the sensitivity when the input voltage signal is very small can be improved, and the saturation of the output voltage can be prevented when the voltage signal is very large. be able to.

In the constant current circuit 42, when the transistor Tr3 is driven, the transistor Tr4 is driven, and a current is supplied from the output terminal to the squibs 26a, 26b, 26c via the transistor Tr4.

When the transistor Tr2 is driven, the transistor Tr5 is driven, and the squibs 26a, 26a and 2 are output from the output terminal via the transistor Tr5.
6b and 26c to supply current to the squibs 26a and 26c.
b, increase the current supplied to 26c.

Further, when the transistor Tr1 is driven, the transistor Tr6 is driven, and the squibs 26a, 26a,
A current is supplied to the squibs 26a, 26c.
b, 26c. Therefore, according to the constant current circuit 44, the squibs 26a, 26
The current supplied to 6b and 26c can be increased gradually, that is, continuously.

Next, the operation of the airbag control device at the time of a vehicle collision will be described. If a deceleration equal to or greater than a predetermined value is detected by the G sensor 22 during a vehicle collision, the detected deceleration is output to the microcomputer 24. The microcomputer 24 outputs a control signal corresponding to the input deceleration to the current control circuit 20. In response, the current control circuit 20 supplies a current having a current value corresponding to the input control signal to the squibs 26a,
26b and 26c.

In this case, the resistor R1 is connected in series with the squib 26b, and the resistors R1 and R2 are connected in series with the squib 26c. Therefore, each squib 26a, 2
6b and 26c, the squib 2
The squib 26b has the largest current value flowing through 6a, and the squib 26c has the smallest current value.

Here, the characteristics of the squib used for the inflator will be described. The squib operates reliably when a current equal to or greater than a predetermined current value (eg, 2 amps) flows for a predetermined time (eg, 2 milliseconds). That is, even when a current equal to or less than the predetermined current value flows through the squib for a predetermined time or more, the squib does not always operate reliably. Therefore, the squib 26a
When a current equal to or more than the predetermined current value flows through the squib 26b and only a current equal to or less than the predetermined current value flows through the squibs 26b and 26c, only the squib 26a operates.
Then, with the increase in the supplied current value, the squib 26
b and 26c operate sequentially.

In this airbag control device, a current corresponding to the impact at the time of a vehicle collision is supplied to the squib 26a,
When the impact is small, only the squib 26a or only the squib 26a and the squib 26b are operated to supply the squib 26b and 26c.

According to the airbag control device of this embodiment, the squibs 26a, 26b and 26c can be operated sequentially, and when the impact at the time of a vehicle collision is small, only the squib 26a or the squib 26a, 26b, 26c is used. 26a and only the squib 26b can be operated,
The occupant can be effectively protected.

Further, since the squibs 26a, 26b, 26c are connected in parallel to the two electric wires, the installation space for the electric wires can be narrowed, and the cost can be reduced.

Further, since the current value supplied to the squibs 26a, 26b, 26c is increased gradually, that is, continuously, the discarded current is reduced as compared with the case where a constant current value is always supplied to a plurality of squibs. Can be reduced.

In the above embodiment, three squibs are connected in parallel to two electric wires, but four or more squibs can be connected in parallel. Also in this case, the squib can be operated stepwise by controlling the current value supplied to the squib.

The current control circuit is not limited to the current control circuit used in this embodiment, but can be changed to a circuit having similar characteristics.

[0042]

According to the present invention, a current can be supplied to a plurality of squibs by two electric wires, and by changing the current value of the supplied current, only a desired squib among the plurality of squibs can be supplied. Can be selectively activated. Therefore, protection of the occupant can be effectively performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of an airbag control device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of an output gain variable amplifier and a constant current circuit used in the airbag control device according to the embodiment of the present invention.

FIG. 3 is a graph showing output characteristics of an output gain variable amplifier used in the airbag control device according to the embodiment of the present invention;

[Explanation of symbols]

10 DC-DC converter, 12 switch, 14
DC power supply, 16 backup power supply, 18 safing sensor, 20 current control circuit, 22 G sensor, 24
... microcomputer, 26a, 26b, 26c ... squib, 28 ... CPU monitor, 30 ... lamp drive circuit,
32 ... indicator lamp, 34 ... 5V power supply, 40a,
40b: electric wire, 42: variable output gain amplifier, 44: constant current circuit, R1, R2, R3, R4: resistor.

Claims (5)

[Claims] 1. An airbag control device having a plurality of inflators and controlling the operation of an airbag device having a plurality of squibs for operating each of the plurality of inflators, comprising: A supply current value control means for performing supply with two electric wires, connecting the plurality of squibs in parallel, and controlling the squibs to be supplied with currents having different current values; An airbag control device characterized by selectively operating only the airbag. 2. The airbag control device according to claim 1, wherein the supply current value control unit supplies currents having different current values to the plurality of squibs due to an impact applied to a vehicle. 3. The supply current value control means further comprises: connecting a resistor in series to at least one of the plurality of squibs to provide a current having a different current value to each of the plurality of squibs. The airbag control device according to claim 1, wherein the airbag control device supplies the airbag. 4. The apparatus according to claim 1, wherein the plurality of inflators are constituted by three or more inflators.
The airbag control device according to any one of claims 1 to 3. 5. The airbag control device according to claim 1, wherein the supply current value control means changes a current value supplied to the plurality of squibs continuously.