JPH06219236A - Air bag system - Google Patents

Abstract

PURPOSE:To prevent an air bag from its non-explosion or misexplosion due to a trouble of a safety switch, in an air bag system. CONSTITUTION:In an air bag system provided with an impact sensor 6 for sensing an impact to turn on a switch 5 between a squib 1 and a power supply 2 and a backup capacitor 9 with the one end connected between the switch 5 of the impact sensor 6 and the power supply 2, a series circuit 13 of an LED11 for informing electrification and a safety switch 10, turned on at the time of removing an air bag module, is connected in parallel relating to a series circuit of the switch 5 and the squib 1. Accordingly, when provided apprehension of non-explosion or misexplosion, the LED11 is lighted to generate an alarm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag for abruptly inflating an airbag (airbag) between a passenger and a dashboard or a steering wheel at the time of a collision of an automobile to reduce an impact on the passenger. Regarding the system.

[0002]

2. Description of the Related Art Generally, in an air bag system, an impact sensor senses an impact at the time of a collision of an automobile, and a switch of the sensor is turned on to energize a squib serving as a starting element from a battery power source. With the heat generated by the above, the explosive such as zirconium perchlorate is ignited to generate heat and pressure, and the sodium nitride is ignited to generate nitrogen gas to rapidly inflate the airbag.

Further, even when power from the battery power source is not supplied due to disconnection, when the switch of the shock sensor is turned on, the squib is energized so that the power supply between the battery power supply and the switch of the shock sensor is set. A backup capacitor is provided in parallel with the series circuit of the switch and the squib.

In such an air bag system, an air bag module including an air bag, an impact sensor, an inflator for supplying high-pressure nitrogen gas to the air bag, a required circuit, and the like is detachably attached to a steering wheel.

When the airbag module is removed, the ignition switch is turned off, so that the power supply from the battery power supply is cut off. The squib is energized from the backup condenser of the above, and the airbag is inflated by mistake, so-called erroneous explosion occurs. A safety switch is provided to prevent the squib from being energized.

[0006]

However, in such an air bag system of the prior art, when the safety switch is short-circuited, both ends of the squib are always short-circuited. Even if the switch is turned on, the squib is not energized, so the airbag does not operate normally, resulting in so-called non-explosion. Also, even if the safety switch is turned on when the airbag module is removed, the safety switch has poor contact. When the charge of the backup capacitor cannot be completely discharged due to
If a shock is applied accidentally, the backup capacitor will energize the squib, resulting in an accidental explosion.

Therefore, the conventional example has a drawback that the system cannot be realized unless the safety switch has very high reliability.

The present invention has been made in view of the above points, and it is an object of the present invention to prevent a non-explosion or an erroneous explosion by giving a warning of a risk of non-explosion or erroneous explosion due to a failure of a safety switch. And

[0009]

In order to achieve the above-mentioned object, the present invention is constructed as follows.

That is, in the airbag system of the present invention, a starting element for starting the airbag when energized and a switch which is turned on in response to a shock are built in, and the switch serves as the energizing power source. In an airbag system including an impact sensor connected in series between a start-up element and a backup capacitor having one end connected to a connection portion between the power supply and the switch, a series circuit of the switch and the start-up element In parallel with this, a series circuit of an alarm for notifying energization and a safety switch that is turned on when the airbag module is removed is connected.

[0011]

According to the above structure, the series circuit of the alarm for notifying the energization and the safety switch that is turned on when the airbag module is removed is connected in parallel to the series circuit of the switch of the shock sensor and the activation element. Therefore, if the safety switch has a short circuit failure, the alarm notifies the energization, so you can know in advance the non-explosion of the airbag,
Also, when the safety switch is turned on when the airbag module is removed, the alarm informs the energization while the backup capacitor is charged, and during the alarm, there is a risk of accidental explosion due to impact. You can know in advance.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of a main part of an embodiment of the present invention.

This air bag system includes a squib 1 as a starting element for activating an inflating operation of an air bag by igniting explosives (not shown) by generating heat when energized, and the squib 1 and the battery power supply 2. Between,
An impact sensor 6 which has an internal switch 5 connected through an ignition switch 3 and a diode 4, senses an impact, turns on the switch 5 and energizes the squib 1, a switch 5 of the impact sensor 6 and a battery. One end is connected to the power supply 2 via the ignition switch 3, the diode 4, and the charging resistor 7, and the other end is grounded, and the battery power supply 2 is disconnected due to disconnection.
A backup capacitor 9 for energizing the squib 1 via the diode 8 and the switch 5 of the impact sensor 6 at the time of impact is provided even when power is not supplied from the device.

In this embodiment, in order to prevent a non-explosion at the time of a collision during normal running and an erroneous explosion at the time of detaching the airbag module, the following construction is made.

That is, when the airbag module is removed, even if a shock is applied and the switch 5 of the shock sensor 6 is turned on, a safety switch 10 is provided so as to prevent the squib 1 from being energized by the backup capacitor 9 due to an accident. And a series circuit 13 including a resistor 12 and an LED 11 as an annunciator that lights up when energized to report energization.
Are connected in parallel to a series circuit composed of the switch 5 of the impact sensor 6 and the squib 1, and in this embodiment, when the airbag module is removed,
A discharge resistor 14 is connected in parallel with the LED 11 and the resistor 12 in order to rapidly discharge the charge of the backup capacitor 9.

FIG. 2 is a vertical cross-sectional view of the steering wheel portion showing the mounted state of the airbag system having the above-mentioned structure.

In the figure, 15 is a steering wheel and 16 is an airbag module. The airbag module 16 includes an airbag 17 and an inflator 18 for supplying high-pressure nitrogen gas to the airbag 17. And the impact sensor 6, the circuit portion 19, the normally-closed safety switch 10 and the LED 11 are attached.

The airbag module 16 is attached to the steering wheel 15 by a bolt 20. In a normally attached state, the normally closed type safety switch 10 is in an off state because the contact is pressed by the protrusion 15a of the steering wheel 15. Since the pressing by the projection 15a is released when the airbag module 16 is removed, the safety switch 10 is turned on.

As shown in FIG. 3, the safety switch 10 may be configured to be pressed by the tip of the bolt 20 instead of the protrusion 15a of the steering wheel 15.

Next, the operation of the airbag system having the above structure will be described.

First, during normal running, the ignition switch 3 is on, power is supplied from the battery power supply 2, and the safety switch 10 is off. In this state, a collision occurs and the impact sensor 6
When the switch senses a shock and turns on switch 5, squib 1
The squib 1 generates heat by being energized, thereby igniting gunpowder or the like and inflating the airbag 16 rapidly, thereby alleviating the impact on the occupant.

Here, when the safety switch 10 has a short circuit failure, the LED 11 as an annunciator is energized and the LED 11 lights up, so that it can be known and can be dealt with in advance. Thus, it is possible to prevent non-explosion at the time of collision.

Next, when the airbag module 16 is removed, the ignition switch 3 is off, and the safety switch 10 is disengaged from the projection 15a of the steering wheel 15 as described above.
It will be turned on. As a result, the charge of the backup capacitor 9 is rapidly discharged via the discharge resistor 14, and the LED 11 is also energized and the LED 11 is turned on until the charge of the backup capacitor 9 is exhausted.

Therefore, charge remains in the backup capacitor 9 until the LED 11 is turned off.
It can be seen that there is a risk of accidental explosion due to the impact, and therefore the worker can interrupt the work to prevent accidental explosion until the charge is completely exhausted.

FIG. 4 is a circuit diagram of another embodiment of the present invention. Parts corresponding to those of the embodiment of FIG. 1 are designated by the same reference numerals.

In this embodiment, a buzzer 21 is used as an alarm in place of the LED 11 described above, and other configurations are the same as those in the above-mentioned embodiments.

In this embodiment, when the safety switch 10 has a short-circuit fault, the buzzer 21 gives a notification, and also when the air bag module is removed, the backup capacitor 9 also has a charge remaining. The buzzer 21 will inform.

FIG. 5 is a circuit diagram of another embodiment of the present invention. Parts corresponding to the embodiment of FIG. 1 are designated by the same reference numerals.

Although the parallel circuit of the LED 11 and the discharge resistor 14 connected to the safety switch 10 is connected to the connection point of the backup capacitor 9 and the diode 8 in the above-described embodiment, in this embodiment, the impact sensor is used. 6 and a connection point on the cathode side of the diode 8 respectively. Other configurations are similar to those of the embodiment shown in FIG. In the embodiment of FIG. 5, L
Of course, the buzzer 21 may be used instead of the ED 11.

Further, in each of the above-described embodiments, the discharge resistor 14 for rapidly discharging is provided, but the discharge resistor 14 may be omitted.

[0032]

As described above, according to the present invention, in parallel with the series circuit of the switch of the impact sensor and the activation element, the alarm for informing the energization and the safety switch which is turned on when the airbag module is removed. Since a series circuit with is connected, if the safety switch has a short circuit failure,
Since the alarm informs of the energization, it is possible to know in advance the non-explosion of the airbag, and when the safety switch is turned on when the airbag module is removed, the alarm is activated while the backup capacitor is charged. Since the energization is notified, it is possible to know in advance that there is a risk of erroneous explosion due to impact during the notification, thereby preventing non-explosion and erroneous explosion.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a steering wheel portion showing an attached state of an airbag module.

FIG. 3 is a cross-sectional view showing a mounted state of a safety switch according to another embodiment of the present invention.

FIG. 4 is a circuit diagram of another embodiment of the present invention.

FIG. 5 is a circuit diagram of still another embodiment of the present invention.

[Explanation of symbols]

 1 Squib (starting element) 2 Battery power supply 5 Switch 6 Impact sensor 9 Backup capacitor 10 Safety switch 11 LED (informer) 21 Buzzer (informer)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yuko Higashihara, 10th Hanazono Dodocho, Ukyo-ku, Kyoto City, Kyoto Prefecture Omron Co., Ltd. Within Muron Co., Ltd.

Claims (1)

[Claims] 1. A start-up element for starting an airbag when energized and a switch that is turned on in response to a shock are built-in, and the switch is connected in series between the energizing power source and the start-up element. In an airbag system including a shock sensor connected to the power supply and a backup capacitor having one end connected to a connection portion between the power supply and the switch, energization is performed in parallel with the series circuit of the switch and the activation element. An airbag system characterized in that a series circuit of an alarm for notifying and a safety switch which is turned on when the airbag module is removed is connected.