JPH01156156A - Air bag controller - Google Patents

Abstract

PURPOSE:To enable an air bag system to be easily restored to the operable condition after the completion of repair by providing in parallel a plurality of system down-switches to make the air bag system inoperative in detecting troubles of the air bag system and be changed over freely. CONSTITUTION:A plurality of sensors provided to sense the collision of vehicles operate an inflator by a control unit 1 upon sensing the collision and expand air bags to protect passengers. Monitor lines to monitor shortcircuit between contacts of respective sensors and disconnection of inflator are connected respectively to trouble sensors 2 in a control unit 1. Current is supplied to a heater 25 in a system down-circuit 20 when troubles are detected to fuse a fuse 21 and make an air bag system inoperative. Thereafter, after the completion of repair, a coupler switch 31 is inserted in external terminals (a)-(d) so that the air bag system can be restored into the operable condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an airbag mounted on a vehicle such as an automobile.

[Prior Art] As is well known, in airbag systems installed in vehicles such as automobiles, which protect occupants by preventing them from colliding with the windshield or steering wheel in the event of a vehicle collision, system activation is Extremely high reliability is required.

In order to meet this requirement and ensure the normal operation of the system, a fault diagnosis device is installed to diagnose whether the system is in a normal state or in a faulty state. It is generally well known that the above-mentioned failure should be promptly repaired by informing the crew of the failure.

For example, in Japanese Patent Publication No. 51-21510, in order to distinguish the causes of abnormal operation of occupant protection devices such as air bags, failures of occupant protection devices are defined as failures that cause the device to operate when it is not needed. A fault diagnosis device for occupant protection systems is proposed that displays and records these two types of faults separately, or performs either one of them. has been done.

By the way, if a malfunction is discovered in the airbag system that causes the system to operate when it is not needed, that is, to cause an abnormal operation in which the airbag inflates even though the vehicle does not collide. Since the abnormal operation described above may cause an accident, inform the occupants of the malfunction and urge them to repair the airbag system as soon as possible, and keep the airbag system inactive until the repair is carried out. There is a need.

For this reason, conventionally, in general, 0N-
A relay is installed to turn off the relay, and if a fault that causes the above abnormal operation is discovered, the relay is turned off.
By activating F and cutting off the power supply circuit, the airbag system is rendered inactive.

However, because the relay has an operating part that can perform ON-OFF operation, it is easily affected by electrical and mechanical disturbances that may occur while the vehicle is running, and the airbag system is in an inactive state. There is a problem of lack of reliability in maintaining the system.

To solve this problem, the power supply circuit of the airbag system is equipped with a system down switch, which consists of a fuse that blows when heated to a predetermined temperature. If a malfunction is detected that causes the airbag to deploy abnormally, the airbag system will be reliably deactivated by blowing the fuse and turning off the system down switch. It is possible to maintain this condition.

[Problems to be Solved by the Invention] However, if a system down switch composed of the above-mentioned fuses is used, it is true that when a failure that causes the above-mentioned abnormal operation is detected in the airbag system, the system-down switch can be shut down. However, once the fuse is blown, it is necessary to restore the system to its normal operating condition after the airbag system has been repaired. It is necessary to remove the control device including a failure detection device for detecting a system failure from the vehicle and restore the system down switch (fuse), which poses a problem in that the restoration work is very time-consuming.

In other words, in an airbag control device, in order to improve the reliability of the device, the fuse is usually fixed directly to the circuit board at both ends by soldering or the like, so it can be easily replaced. If this is not possible and the fuse is blown, it will be necessary to replace it with a new one by soldering on the board, which will require a lot of effort to restore the fuse.

[Purpose of the Invention] This invention has been made in view of the above-mentioned problems, and is aimed at detecting a malfunction in the airbag system that causes an abnormal operation in which the airbag inflates even though the vehicle does not collide. In such a case, after ensuring that the airbag system is maintained in an inoperative state, and once the above-mentioned failure is repaired, the airbag system can be easily returned to a normally operational state without removing the control device. An object of the present invention is to provide an airbag control device that can be restored.

[Means for Solving the Problems] Therefore, the present invention provides a failure detection means for detecting a failure of the airbag system, and a system down switch for disabling the airbag system according to a signal from the failure detection means. In this airbag control device, a plurality of the system down switches described above are provided in parallel, and a switch circuit switching means for switching the plurality of system down switches is provided.

[Effects of the Invention] According to the present invention, the airbag control device is provided with a plurality of system down switches in parallel, and these multiple system down switches can be switched. Once the above malfunction has been repaired after ensuring that it is in an inoperative state, the air hack system can be returned to normal operation by simply switching the system down switch, without removing the control device. can be restored.

[Example] Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

As shown in the electrical circuit diagram of FIG. 4, the airbag system according to the present embodiment includes a control unit l having a built-in failure detection device 2 for detecting a failure of the system, and a control unit l for sensing a vehicle collision. A plurality of front sensors 3, 4 (for example, two) provided at the front of the vehicle body such as a bumper, and a plurality (for example, three) of dash sensors 5, 6, 7 provided on the dash board at the front of the vehicle interior. Above two front sensors 3
, 4 and at least one of the three dash sensors 5, 6.7 detect the collision and
The vehicle is equipped with an inflator 8 that is energized by the N operation and inflates an airbag (not shown) using a well-known mechanism to prevent the occupant from colliding with the windshield or steering wheel.

Further, a power source 11 is connected to the control unit 1 via a protective fuse 13 that prevents excessive current from flowing through the unit l. A capacitor 12 is connected thereto, which acts as an auxiliary power source in the event of a failure.

One end of the inflation flake 8 is connected to the power line L of the airbag system via the control unit 1, and front sensors 3 and 4 arranged in parallel with each other are connected, while the other end is connected to a terminal. Dash sensors 5 and 6 are each grounded and arranged in parallel with each other.
．． 7 is connected, one of the front sensors 3 and 4 is turned on, and the dash sensor 5 is turned on.
゜When any one of 6.7 is turned on, a current flows through the heater 8R in the inflator 8, which generates heat, which detonates the explosive part (not shown) and causes the airbag (not shown) to explode. It is designed to expand.

In addition, the front sensors 3 and 4 and the dash sensor 5
, 6.7, resistors 3R, 4R, 5R, 6R, and 7R are provided in parallel between the contacts of each sensor 3, 4.5.6.7, respectively, and as shown by broken lines in the figure, Monitor lines 3 L 412.5 f2.6 Q and 712 are provided to monitor short circuits between the respective contacts, and a monitor line 8a is provided to the inflator 8 to monitor disconnection of the heater 8R. ,
Each of the above monitor lines 3f2, 4L5 (2,6I2゜7Q
, 8Q are all connected to the failure detection device 2 within the control unit 1.

A weak current of a predetermined current value is always flowing through the front sensors 3, 4, the inflation flakes 8, and the dash sensors 5, 6, and 7 for monitoring purposes, and each sensor 3 should be in an open state under normal conditions. , 4.5.6.7, respectively, when the current values of the currents flowing through the monitor lines 3Q and 4 increase.
The failure detection device 2 detects this via D, , 5Q, 6Q, and 7Q, and detects a short circuit in the sensor whose current value has increased. Furthermore, when current does not flow between both terminals of the inflator 8, which should normally be in a conductive state, a disconnection of the inflator 8 is detected by the failure detection device 2 via the monitor line 8Q. .

The failure detection device 2 detects the sensor 3°4.5.
, 6.7 and inflation 8, etc., when a failure of the airbag system is detected, a command signal is output to the alarm circuit 15 connected to the power supply 11 via the operation switch 14, which is usually also used as an ignition switch. The alarm circuit 1
5 is activated to notify the occupants of the failure of the airbag system, for example, by means of a lamp (not shown) or a buzzer (not shown).

Furthermore, the electrical resistance values of the resistors 3R, 4R, 5'R, 6R, and 7R provided in each of the above-mentioned sensors 3.4, 5.6.7 are compared to the electrical resistance value of the heater 8R of the inflator 8. Even if the weak current for monitoring is applied, one of the front sensors 3 and 4 will be in the ON state (the contact is closed), and the dash sensors 5 and 6. Unless one of them is turned on, the current flowing through the inflator 8 is weak and is set so as not to cause an explosion part (not shown) to explode.

By the way, in the control unit l according to the present embodiment, when the failure detection device 2 detects a short circuit in the front sensors 3, 4 and the dash sensor 5, 6, 7, the air A system down circuit 2o is provided in the power supply line L in order to immediately deactivate the airbag system when a failure that causes an abnormal operation in which the bag (not shown) opens is detected.

This system down circuit 2o will be explained below.

As shown in detail in FIG. 3, the system down circuit 2
0 is provided on the side surface of the control unit h1, and includes a first fuse 21 interposed in series with the power supply line L of the airbag system, and a first fuse 21 disposed in parallel with the first fuse 21. In the vicinity of these fuses 21 and 22, a first heater 25 and a second heater 26 are respectively provided in a first heater circuit 23 and a second heater circuit 24 arranged in parallel with each other. is set up.

The second fuse 22 has one end connected to the connection point L2 of the power line L, and the other end connected to the system down circuit 20.
The external terminal C that makes a pair with the terminal d is connected to the power supply line L at a connection point. In the normal state shown in FIG. 3, the external terminals C and d are not connected, so power is supplied to the airbag system from the first terminal as shown by the solid arrow ■ in FIG.
This is done through the fuse 21, and no current flows through the second fuse 22.

Incidentally, the first fuse 21 and the second fuse 22 are both used to control the control device 1 against vibrations, shocks, etc. while the vehicle is running.
In order to increase the reliability of the system down circuit 20, it is directly fixed to the circuit board of the system down circuit 20 by soldering both ends thereof.

Further, the first heater circuit 23 has both ends connected to the failure detection device 2.
The second heater circuit 24 has one end connected to the first heater circuit 23, and the other end connected to the external terminal of the system down circuit 20, and the second heater circuit 24 has one end connected to the first heater circuit 23, and the other end connected to the external terminal of the system down circuit 20, and the second heater circuit 24 is connected to the external terminal that is paired with the terminal. Terminal a is connected to the first heater circuit 23. In the normal state shown in FIG. 3, the external terminal a and the external terminal A are not connected, so the second heater circuit 2
No current flows through 4.

In the system down circuit 20 configured as described above, the failure detection device 2 is the front sensor 3.

4 and the dash sensors 5, 6.7, the first heater circuit 23 is activated by a command signal from the failure detection device 2, and as shown by the dashed arrow ■ in FIG. A current flows through the first heater circuit 23, the first heater 25 is heated, and the first fuse 21 is blown. In other words, the power line L of the airbag system is cut off.

By the way, as shown in FIG. 2, the external terminals a, b, c, and d of the system down circuit 20 are connected to the control unit l.
A so-called coupler switch 31 can be connected from the outside to short-circuit the terminals a and b1 and the terminals C and d, respectively.

That is, as shown in FIG. 1, the coupler switch 31 includes two sets of connection terminals, terminals a' and b', and terminals C' and d', which are short-circuited to each other. The switch 31 is connected to the external terminals a, b, and c of the system down circuit 20 of the control unit 1.

By inserting and installing the cover switch 31 into the connecting terminal a, as shown by the broken line in FIG.
', b'c', and d' are the system down circuit 20
are connected to external terminals a, b, c, and d of the system down circuit 20, respectively, and terminal a and terminal A of the system down circuit 20 and terminal C and terminal d are respectively short-circuited.

Therefore, the power line L (see FIG. 1), which has been cut off by the first fuse 21 being blown, can be connected to the power line L (see FIG. 1) by inserting the cover switch 31, as shown by the broken line in FIG. L2 is terminal c, c', d'
, d and the second fuse 22, and the current shown by the solid arrow 2 in FIG. 1 flows through the power supply line L, so that the airbag system is restored to its normal operational state. Also, by inserting the coupler switch 31, terminal a is short-circuited, so
Since the second heater circuit 24 is connected to the failure detection device 2, the front sensors 3, 4 and the dash sensor 5.
6.7, when the short circuit is detected, the second heater circuit 24 is activated by a command signal from the failure detection device 2.
is activated, and the current shown by the dashed arrow ■ in FIG. 1 flows through the second heater circuit 24 and heats the second heater 26, thereby making it possible to blow out the second fuse 22. .

That is, after the first fuse 21 is blown and the repair of the airbag system is completed, the cover switch 31 is connected to the external terminals a, b, c, and d of the system down circuit 20 from outside the control unit l. By doing so, the fuse serving as the system down switch can be switched from the first fuse 21 to the second fuse 22, and the airbag system can be restored to an operable state.

As described above, according to the present embodiment, the airbag system control unit 1 includes a fuse 2 serving as a system down switch for disabling the airbag system.
1.22 are provided in parallel, and these multiple fuses (first fuse 21 and second fuse 22) are connected to the external terminals a, b, c, d of the system down circuit 20 from the outside of the control unit 1. By inserting the coupler switch 31 into the airbag system, the airbag system can be used even if the vehicle does not collide even if the front sensors 3, 4 and dash sensors 5, 6, 7 are short-circuited. When a failure that causes an abnormal operation in which an airbag (not shown) opens is detected, the first fuse 21 is blown, and the power line L of the airbag system in which the first fuse 21 is interposed is cut off. After the system has been put into an inoperable state and the repair of the above-mentioned failure is completed, the coupler switch is connected to the external terminals a, b, c,
With the simple operation of plugging the system into It can be restored to normal operating condition.

Furthermore, in this embodiment, fuses 21 and 22, which are blown by heating from heaters 25 and 26, are used as system down switches to disable the air bag system, and the system down switches (fuses 21 and 22) are
2) Since the coupler switch 31, which is inserted into and attached to the control unit l, is used as the switch circuit switching means for switching the 2), it is possible to
The reliability of the airbag system can be improved because it is not affected by electrical and mechanical disturbances that may occur while the vehicle is running.

Note that the above embodiment has two system down switches (
Fuses 21 and 22) were installed in parallel,
In the present invention, by providing more fuses in parallel and increasing the number of external terminals of the system down circuit in accordance with the addition of the fuses, the system can be shut down by the number of fuses, and the system can be shut down by inserting a coupler switch. It is possible to cause the recovery to be performed repeatedly.

[Brief explanation of the drawing]

All drawings are for detailed explanation of the present invention.
Fig. 1 is an electric circuit diagram of the system down circuit, explaining the state in which the coupler switch is inserted, Fig. 2 is a perspective view of the control unit and cabrus inch, and Fig. 3 is the electrical circuit diagram of the system down circuit, explaining the state before the fuse blows. Electrical Circuit Diagram FIG. 4 is an electrical circuit diagram schematically showing the airbag system. ■...Control unit, 2...Failure detection device, 20.
...System down circuit, 21...1st fuse, 2
2...Second fuse, 25...First heater, 26...
...Second heater, 31...Coupler switch.

Claims (1)

[Claims] (1) In an airbag control device comprising a failure detection means for detecting a failure of the airbag system, and a system down switch for disabling the airbag system in accordance with a signal from the failure detection means, An airbag control device comprising a plurality of switches arranged in parallel and a switch circuit switching means for switching the plurality of system down switches.