JPH0637018Y2 - Air bag system - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention prevents a light emitting diode whose lighting is controlled by a diagnostic circuit of a system for controlling the deployment of an airbag from accidentally emitting light when the ignition switch is turned off. Airbag system to do.

[Conventional technology]

As a conventional airbag system, for example, there is one as shown in FIG. In FIG. 2, reference numeral 1 is an in-vehicle battery, 2 is an ignition switch connected to the in-vehicle battery 1, 3 is a controller, 4 is a DC power source for expanding an airbag, and the controller 3 is connected from the in-vehicle battery 1 via the ignition switch 2. The voltage of the battery to be supplied to the
The backup capacitor 7 and the capacitor 7a are charged via.

In this case, the backflow prevention diodes 8a to 8c prevent backflow, and the diode 9 prevents the backup capacitor 7,
The inrush of current to the capacitor 7a is prevented. 10 is CPU
The diagnostic circuit 11 comprises a diagnostic circuit power supply unit, which is supplied with a battery voltage from the vehicle-mounted battery 1 and supplies a predetermined electric power to the diagnostic circuit 10. 12 is a storage unit, and the diagnostic circuit 10
I am trying to exchange data with.

Numerals 14 to 19 are collision detection means provided in each part of the vehicle body, and are constituted by arranging acceleration switches 14a to 19a and resistors 14b to 19b in parallel which close the input and output by a change in acceleration more than a predetermined value.

Reference numeral 20 denotes a squeeze provided in the steering section, which is an electrode provided in the steering section for igniting explosives for deploying an airbag (not shown).

Reference numeral 21 is a spiral cable made of a flexible cord wound around the steering shaft to electrically connect the squeeze 20 and the controller 3 provided on the vehicle body side. The squeeze 20 and the spiral cable 21 constitute an operation control unit 20A that deploys an airbag.

Further, 3a to 3n are output terminals of the controller, and are connected to the line L1 from the output terminal 3a through the collision detection means 14-output terminal 3b-output terminal 3e-coiled cable 21-squeeze 20-output terminal 3f. ing. The output terminals 3f to 3n are connected to the line L1.

Collision detecting means 15 is connected between the output terminals 3a and 3c, 3d.

Also, between output terminals 3g and 3h, between output terminals 3i and 3j, and output terminals
Collision detecting means 16 to 19 are connected between 3k and 3l and between output terminals 3m and 3n, respectively.

The output terminals 3h, 3j, 3l, 3n are connected to the line L2. Line L2 is grounded.

The diagnostic circuit 10 in the controller 3 is grounded via the connector harness 30 and the switch SW, and
Relay 27 via alarm lamp La from connector harness 31
It is connected to the.

Here, the relay 27 has an exciting coil 27b and a normally open contact 27a. One end of the normally open contact 27a is connected to the alarm lamp La and the other end is connected to the positive electrode of the vehicle battery 1. Further, one end of the exciting coil 27b is grounded, and the other end is connected to the output side of the ignition switch 2.

Next, the operation will be described. First, when the ignition switch 2 is closed, the voltage from the in-vehicle battery 1 is DC / D.
The voltage is boosted by the C converter 5 and charged to the capacitors 7 and 7a via the diode 8c with a time constant determined by the resistor 6 and the backup capacitor 7, and the charging voltage of the capacitors 7 and 7a is always higher than the voltage of the vehicle battery 1. deep.

The diagnostic circuit 10 inputs the data such as the voltage generated in each of the resistors 14b to 19b, and one of the acceleration switches 14a to 19a is in a state close to a short circuit and the voltage generated between the terminals of the resistors 14b to 19b is normal. When the value becomes different from the time, it is determined and stored in the storage unit 12.

In addition, the storage unit 12 has an acceleration switch due to a collision or the like.
When any of 14a to 19a is turned on, which acceleration switch is turned on is also stored.

In the above configuration, when the vehicle collides and negative acceleration more than a predetermined value occurs, and any one of the acceleration switches 14a and 15a and any one of the acceleration switches 16a to 19a are turned on, the charge stored in the backup capacitors 7 and 7a is charged. But, for example,
Flowing as shown by the broken line, the squeeze 20 generates heat, the powder is ignited, and the airbag is deployed.

Next, the diagnostic circuit 10 causes the storage unit 12 to store any of the resistors 14b to 19b, when an accident such as a wire break occurs, or when an abnormality occurs in the operation control unit 20A, and the lamp A signal is output to the drive circuit 25, its output is set to "L" level, and the alarm lamp La is lit by the current obtained from the normally open contact 27a to notify the failure.

By the way, in such a conventional airbag system, since the capacity of the alarm signal La is large, the current capacity and the shape of the relay 27 become large. Therefore, instead of the alarm lamp La, a light emitting diode is used to reduce the size of the relay 27 and reduce the cost of the entire system.

[Problems to be solved by the device]

However, when an alarm is displayed using such a light emitting diode, when the ignition switch 2 is turned off, the voltage of the resistors 14b to 19b immediately decreases, so that the diagnostic circuit 10 outputs the output of the lamp drive circuit 25. Is set to the “L” level, the current flowing through the exciting coil that is deenergized with a delay causes the light-emitting diode with good responsiveness to light up for a moment, which gives the user a feeling of distrust. there were.

The present invention has been made by paying attention to such a conventional problem. By delaying the time until the output of the lamp drive circuit becomes “L” level after turning off the ignition switch, the above problem is solved. The purpose is to resolve.

[Means for Solving the Problems]

The airbag system according to the present invention retains the logic of the terminal that outputs the alarm signal for a predetermined time after the ignition switch 2 is turned off by the diagnostic circuit of the system that controls the deployment of the airbag. It is something that I tried to leave.

[Action]

The diagnostic circuit according to the present invention determines the logic of the output terminal of the alarm signal based on the detection of the current flowing through the resistance of each collision detection means until a preset time elapses after the ignition switch is turned off. After the above time has elapsed, the output terminal has the same logical state as the output of the alarm signal for the first time, thereby prohibiting the lighting of the light emitting diode for alarm controlled through the relay when the ignition switch is turned off.

[Example of device]

The invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. First, the configuration will be described. 10A is a diagnostic circuit, and this diagnostic circuit 10A has a resistor 14b.
By detecting the voltage between terminals 19b to 19b, the abnormality of each of these resistors 14b to 19b is detected, a signal is output to the lamp drive circuit 25, and the output of the lamp drive circuit 25 is set to the "L" level. In addition, it detects that the ignition switch 2 is turned off and holds the output of the signal to the drive circuit 25 for a predetermined time. The LED is a light emitting diode, one end of which is connected to the normally open contact 27a via a resistor 28 and the other end of which is grounded via a resistor 29.
The output terminal of the lamp drive circuit 25 is connected to the midpoint of the connection with. In addition, the same circuit parts as those shown in FIG. 2 are denoted by the same reference numerals, and the duplicated description thereof will be omitted.

Next, the operation will be described.

After the ignition switch 2 is closed (turned on), when the vehicle collides, one of the acceleration switches 14a to 19a is turned on to turn on the backup capacitor and the capacitor 7a.
The operation of causing the squeeze 20 to generate heat by the electric charge of and to deploy the airbag by igniting the explosive is the same as the conventional one. In addition, the operation of detecting an abnormality of the resistors 14b to 19b and the operation control unit 20A and issuing an alarm by the light emitting diode LED,
Basically the same as the conventional one.

On the other hand, when the ignition switch 2 is closed and the battery voltage is being supplied to the expansion DC power supply 4, if the ignition switch 2 is opened and turned off, the voltage across the resistors 14b to 19b decreases, and Resistor 14b
The same signal as when a disconnection accident occurs in ~ 19b is diagnostic circuit 1
Input to 0A. Therefore, the diagnostic circuit 10A takes in the turning-off of the ignition switch 2 by closing the line 30a and maintains the output signal state in the state before the ignition switch 2 is closed for a predetermined time by the internal timer circuit, The time until the output terminal of the lamp drive circuit 25 becomes "L" level is delayed. As a result, when the ignition switch 2 is turned off, even if a voltage that slowly changes (decreases) is applied to one end of the light emitting diode LED through the relay having a large time constant, the light emitting diode LED is turned on. Therefore, the user does not feel distrust as in the past.

[Effect of device]

As described above, according to this invention, the configuration is delayed by about the delay time of the relay when the ignition switch is turned off to enter the standby mode. Therefore, after the delay time elapses, the output of the lamp drive circuit becomes "L".
Even if the level is set, since the current supply from the relay to the alarm light emitting diode has already stopped, the light emitting diode is not inadvertently turned on, and the user's distrust can be eliminated.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an airbag system according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional airbag system. 1 ... In-vehicle battery, 2 ... Ignition switch,
10A ... Diagnostic circuit, 14-19 ... Collision detection means, 20A ... Actuation control unit, 27 ... Relay, LED ... Light emitting diode.

Claims (1)

[Scope of utility model registration request] 1. An airbag based on a plurality of collision detection means (14) to (19) connected to an on-vehicle battery (1) through an ignition switch (2), and a detection output from the collision detection means. Control unit (20A)
And the operation control section (20A) or the collision detection means (1
4) to (19) are checked for abnormalities, a diagnostic circuit (10A) that outputs an alarm signal, a relay (27) that operates when the ignition switch (2) is turned on, and the diagnostic circuit that operates when the relay operates. (10A) In an airbag system including a light emitting diode (LED) that lights up when an alarm signal is supplied from the diagnostic circuit (10A).
The air bag system is characterized in that the logic of the terminal for outputting the alarm signal is held for a predetermined time after the ignition switch (2) is turned off.