JP2546194Y2 - Air bag device - Google Patents

Description

[Detailed description of the invention] [Industrial applications]

The present invention relates to an airbag device for protecting a passenger safely in a vehicle collision accident.

[Prior art]

2. Description of the Related Art As a conventional airbag device, for example, there is one as shown in FIG. In the figure, 1 is a vehicle battery, 2
Is an ignition switch connected to the vehicle-mounted battery 1, 3 is a controller, 4 is a DC power supply for deploying an airbag (not shown), and the DC power supply 4 is supplied from the vehicle-mounted battery 1 to the controller 3 via the ignition switch 2. The supplied battery voltage is boosted by a DC / DC converter 5 for boosting and boosting, and is charged via a resistor 6 to a large-capacity backup capacitor 7 for airbag deployment. Reference numerals 8a to 8c denote backflow prevention diodes, and 9 denotes a diode for preventing inrush of current into the backup capacitor 7 and for preventing the backup capacitor 7 from deteriorating. Reference numeral 10 denotes a diagnostic circuit including a CPU and the like. Reference numeral 11 denotes a power supply unit for the diagnostic circuit. The battery voltage is supplied from the vehicle-mounted battery 1 and when the ignition switch 2 is turned on, the diagnostic circuit 10 and
A predetermined power is supplied to a non-volatile storage unit 12 such as an EEPROM, and a backup power is supplied to a RAM in the diagnostic circuit 10 when the ignition switch 2 is turned off. Reference numeral 13 denotes a lamp control circuit. The lamp control circuit 13 is connected to the positive electrode of the vehicle-mounted battery 1 via the normally open contact 15a of the lamp 14 and the relay 15. 16a to 16d are diodes, and 17 to 19 are collision detecting means provided in various parts of the vehicle body. The collision detecting means 17 to 19 are acceleration switches 17a for closing input and output at a predetermined acceleration.
To 19a and resistors 17b to 19b are connected in parallel. Reference numeral 20 denotes an ignition device provided in a steering unit or the like. The ignition device 20 serves as an electrode for igniting an explosive for deploying an airbag provided in the steering unit. Next, the operation will be described. When the ignition switch 2 is closed, the voltage from the vehicle-mounted battery 1 is supplied to the diagnostic circuit power supply unit 11 and also to the DC / DC converter 5, where the DC / DC converter 5
And the backup capacitor 7 is charged via the diode 8c with a time constant determined by the resistor 6 and the capacitor 7, and the charging voltage of the backup capacitor 7 is always set higher than the voltage of the vehicle battery 1. The diagnostic circuit 10 inputs data such as the voltage generated in each of the resistors 17b to 19b and the charging voltage of the backup capacitor 7, and any one of the normally open acceleration switches 17a to 19a is in a state close to a short circuit, and the resistor 17b If the voltage generated between the terminals of ~ 19b is different from the normal value,
This is determined as a failure and stored in the nonvolatile storage unit 12, and the lamp 14 is driven in a predetermined mode corresponding to the type of the failure. Further, the nonvolatile storage unit 12 stores which of the acceleration switches 17a to 19a has been turned on due to a collision or the like. In the above configuration, the vehicle collides to generate a negative acceleration equal to or greater than a predetermined value, and among the acceleration switches 17a to 19a, the acceleration switch 17a and the acceleration switch 18a or the acceleration switch
When one of the acceleration switch 17a and the acceleration switch 19a or the acceleration switch 17a, the acceleration switch 18a and the acceleration switch 19a is turned on, the electric charge charged in the backup capacitor 7 flows. Then, the ignition device 20 generates heat, the explosive is ignited, and the airbag is deployed, so that the occupant is protected.

[Problems to be solved by the invention]

However, in such a conventional airbag device, whether the passenger is an adult or a child is reliable.
In order to safely deploy the airbag, the two collision detection means are opened at an angle of approximately 45 degrees with respect to the front-rear direction on the upstream side where the current of the ignition device 20 flows and on the downstream side opposite to the upstream side. Since the collision detection means is turned on when both of the collision detection means detect the acceleration, the current is supplied from the backup capacitor 7 to operate the airbag system, the number of collisions corresponding to the number of the ignition devices 20 is increased. Since the detection means is required, the cost increases, and there is a problem that it is difficult to ensure that the collision detection means is turned on, that is, it is difficult to ensure the reliability. The present invention has been made in view of such a conventional problem, and has as its object to provide an airbag device capable of reducing the number of collision detecting means, reducing cost and improving reliability. .

[Means for Solving the Problems]

The airbag device according to the present invention includes an ignition device connected in parallel between terminals of a DC power supply for igniting explosives, and a collector terminal connected to one end of each of the plurality of ignition devices. A transistor for driving an ignition device in which an emitter terminal is connected to a terminal of each of the first and second terminals, and the other end of each of the plurality of ignition devices is connected in common to detect a magnitude of an acceleration signal equal to or greater than a predetermined value generated by a collision.
Connected to a base terminal of each of the ignition device driving transistors, operates upon receiving a diagnostic signal from a diagnostic circuit, and includes at least the ignition device driving transistor in each of the ignition device driving transistors. A plurality of diagnostic transistors for supplying a small diagnostic current for diagnosing the ignition device and the ignition device, and a magnitude of an acceleration signal equal to or greater than a predetermined value, which is connected to a base terminal of each of the ignition device driving transistors and is generated by a collision. And a plurality of switching transistors for supplying an ignition current to each of the ignition device driving transistors in response to a detection signal of the second collision detection means for detecting the ignition timing.

[Action]

The airbag device according to the present invention connects the first collision detection means to one end of each of the plurality of ignition devices, and connects the second collision detection means to the other end of the plurality of ignition devices. The ignition device is driven by operating an ignition device driving transistor based on a collision signal detected by the second collision detection means.

【Example】

Hereinafter, this invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, the same or equivalent components as in FIG. First, the configuration will be described. In the figure, reference numeral 21 denotes, for example, an ignition device on a driver's seat side, 22 denotes, for example, a main ignition device for primary deployment of an airbag on a passenger seat side, and 23 denotes, for example, a fully deployed airbag on a passenger seat side. These auxiliary ignition devices
21, 22, and 23 are connected in parallel. 24 is the ignition device 21, 22, 23
DC power supply for applying a voltage to the ignition device driving transistors 25a, 25b, 25c to the DC power supply 24.
Is configured so that the battery voltage is boosted by the DC / DC converter 5 for raising and lowering the voltage and charged into the large-capacity backup capacitors 7a, 7b, 7c for deploying the airbag via the resistors 6a, 6b, 6c. . 8a to 8g are backflow prevention diodes, 9
Reference numerals a, 9b, and 9c denote diodes that prevent inrush of current into the backup capacitors 7a, 7b, and 7c, and that prevent the backup capacitors 7a, 7b, and 7c from deteriorating. 26a, 26b, 26c are ignition device driving transistors 25a, 25b, 2
5c, a diagnostic transistor for performing a failure diagnosis between the collision detection means described later and the ignition devices 21, 22, and 23.
26a, 26b, 26c are ignition device drive transistors 25a, 25b, 25c
And operates according to a diagnostic signal from the diagnostic circuit 10. Reference numeral 27 denotes second collision detecting means connected to one end of each of the ignition devices 21 and 22 via ignition device driving transistors 25a and 25b, switching transistors 28a and 28b, and a transistor 29. 27 is connected to one end of the ignition device 23 via a transistor 29, a delay circuit 30, a switching transistor 28c and an ignition device driving transistor 25c. Reference numeral 31 denotes a first collision detection means connected to the other end of each of the ignition devices 21, 22, and 23 via a diode 16. Next, the operation will be described. When the ignition switch 2 is closed, the voltage from the vehicle-mounted battery 1 is supplied to the diagnostic circuit power supply unit 11 and also to the DC / DC converter 5, where the DC / DC converter 5
And is charged to the backup capacitors 7a, 7b, 7c via the diodes 8c, 8e, 8g with a time constant determined by the resistors 6a, 6b, 6c and the capacitors 7a, 7b, 7c, and the backup capacitors 7a, 7b, 7c Is always set higher than the voltage of the vehicle-mounted battery 1. When the ignition switch 2 is closed, the second and first collision detecting means 27, 31 are diagnosed. When there is no failure, the ignition devices 21, 22, 23 are diagnosed. Device drive transistors 25a, 25
Diagnose b, 25c. As a diagnosis, a high-level signal is output from the diagnostic circuit 10 to turn on the diagnostic transistors 26a, 26b, 26c, and the voltage applied to the ignition devices 21, 22, 23 at this time is determined by the diagnostic circuit.
Diagnose by 10. That is, the potential difference between both ends of the ignition devices 21, 22, and 23 is detected by a differential amplifier in the diagnostic circuit 10, and the output voltage of the differential amplifier is compared with a reference voltage to compare the ignition devices 21, 22 and 23 with each other.
A diagnosis is made as to whether or not the voltages of 2, 23 are generated at a predetermined value or more.
When the voltages of the ignition devices 21, 22, and 23 do not exceed a predetermined value, it is diagnosed that the diagnosis transistors 26a, 26b, and 26c have failed. If all of the ignition device driving transistors 25a, 25b, 25c are normal, a low level signal is sent to the diagnosis transistors 26a, 26b, 26c to turn off the diagnosis transistors 26a, 26b, 26c. At this time, the ignition device driving transistors 25a, 25b, 25c
Is turned off by the voltage of the ignition devices 21, 22, and 23 (in this case, the first collision detection means 31 is not turned on). In this case, if the second collision detecting means 27 is turned on, the ignition device driving transistors 25a, 25b, 25c are turned on, so that the ignition device is operated under the condition that the collision detecting means 27 is turned off. The drive transistors 25a, 25b, and 25c are diagnosed. In the above configuration, when the vehicle collides and a negative acceleration exceeding a predetermined level is generated and the acceleration switches of the second and first collision detecting means 27 and 31 are turned on, the backup capacitor
Charges charged to 7a, 7b, 7c flow. Then, the transistor 29 and the switching transistors 28a and 28b
Further, the ignition device driving transistors 25a and 25b are turned on, the ignition devices 21 and 22 generate heat, the explosive is ignited and the airbag in the driver's seat is deployed, and the airbag in the passenger's seat is moved to the first position.
Expand next. Then, the switching transistor 28c and the ignition device driving transistor 25c are turned on with a predetermined time lag by the delay circuit 30, and the ignition device 23 generates heat, the explosive is ignited and the airbag in the passenger seat is deployed secondarily, and the passenger is boarded. Will be protected.

[Effect of the invention]

As described above, according to the present invention, between the terminals of the DC power supply, a plurality of igniters connected in parallel for igniting gunpowder, and a collector terminal is connected to one end of each of the plurality of igniters. An ignition device driving transistor having an emitter terminal connected to the terminal of the DC power supply, and the other end of each of the plurality of ignition devices is commonly connected to detect a magnitude of an acceleration signal equal to or greater than a predetermined value generated by a collision. Connected to a base terminal of each of the ignition device driving transistors, and operates upon receiving a diagnostic signal from a diagnostic circuit. A plurality of diagnostic transistors for supplying a small diagnostic current for diagnosing the drive transistor and the ignition device; The ignition signal is supplied to the respective ignition device driving transistors in response to the detection signal of the second collision detection means which is connected to the base terminal of the transistor and detects the magnitude of an acceleration signal equal to or greater than a predetermined value generated by the collision. Since a configuration including a plurality of switching transistors is used, the effect is obtained that the number of collision detection means can be reduced by sharing the same, and the cost can be reduced and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an airbag device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional airbag device. 21, 22, 23 ... Ignition device, 25a, 25b, 25c ... Ignition device drive transistor, 26a, 26b, 26c ... Diagnostic transistor, 28a, 28b, 28c ... Switch transistor, 31 ...
First collision detecting means, 27... Second collision detecting means.

Claims (1)

(57) [Scope of request for utility model registration] An ignition device connected in parallel between terminals of a DC power supply for igniting explosives, a collector terminal connected to one end of each of the plurality of ignition devices, and an emitter connected to a terminal of the DC power supply. An ignition device driving transistor having a terminal connected thereto, first collision detection means for detecting the magnitude of an acceleration signal equal to or greater than a predetermined value generated by a collision, and the other end of each of the plurality of ignition devices being commonly connected; , Connected to a base terminal of each of the ignition device driving transistors, receives a diagnostic signal from a diagnostic circuit, and operates.
A plurality of diagnostic transistors for supplying at least a small diagnostic current for diagnosing the ignition device driving transistor and the ignition device to the respective ignition device driving transistor; and a base terminal of the respective ignition device driving transistor. A plurality of switches connected to a plurality of switches for receiving a detection signal of a second collision detecting means for detecting a magnitude of an acceleration signal equal to or more than a predetermined value generated by the collision and supplying an ignition current to each of the ignition device driving transistors. An airbag device including a transistor.