JPH0732968A - Vehicular air bag device - Google Patents

Abstract

PURPOSE:To let an air bag is actuated by judging that squibs fail due to shortcircuiting by a controller based on a signal from an operation detecting means, and thereby feeding sufficient current capable of igniting all of the normal squibs even if more than one squib fail due to shortcircuiting. CONSTITUTION:At the time of collision, it is judged by a controller 4 based on signals from a crush sensor whether impact is caused by collision or by bad roads, and when it is judged that impact is caused by collision, ignition means 11 through 14 are driven, and current is fed to squibs so as to allow them to be ignited. Before current is fed to the squib 21 which has failed due to shortcircuiting, that is, before an ignition means 11 is turned on, ignition means 12 through 14 are turned on so as to allow current to be fed to the normal squibs 22 through 24, they are ignited, the ignition means 11 is then turned on thereafter, and current is then fed to the squib 21 which has failed due to shortcircuiting. By this constitution, current is thereby prevented from being concentrated to the squib 21 which has failed due to shortcircuiting, so that sufficient current capable of igniting the normal squibs 22 through 24 can thereby be fed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can actuate a plurality of airbags or an airbag and a pretensioner type seat belt with a time lag so that current can be supplied to a normal squib even when there is a short-circuited squib. The present invention relates to a possible vehicle airbag device.

[0002]

2. Description of the Related Art Conventionally, there is an airbag device to which a squib is connected, which detects the impact of a vehicle at the time of a collision with a crash sensor and which is energized based on the signal to ignite explosive. When two or more squibs are connected in parallel by a system and one of the plurality of squibs has a short-circuit fault, current concentrates on the short-circuited squib during ignition, and The current enough to ignite the squib does not flow.

Therefore, as disclosed in Japanese Patent Laid-Open No. 4-321454, constant current control is performed so that a constant current flows through each squib, so that the current concentrates on one short-circuited squib. It is possible to supply enough current to ignite other squibs.

[0004]

However, providing a means for supplying a constant current to each squib complicates the circuit and increases the cost. Therefore, the present invention provides a system capable of supplying a sufficient current to a normal squib and operating an airbag even if there is a squib that has a short circuit failure without requiring a special circuit.

[0005]

[Means for solving the problems] Therefore, short-circuit detection is performed as a part of the fail-safe function, and a short-circuited squib is supplied with current to another normal squib to ignite it to operate the airbag and then short-circuited. By supplying current to the squib and igniting it, it is possible to solve the problem of non-explosion without requiring a special circuit such as a constant current circuit.

[0006]

According to the present invention, a short circuit is detected in the squib, a current is supplied to the normal squib to cause a short circuit, and then a current is supplied to the normal squib. It is possible to prevent the problem that the current is concentrated on the malfunctioning squib and the sufficient current for igniting the normal squib cannot be supplied.

[0007]

FIG. 2 shows an embodiment according to the present invention. 11-
Denoted at 14 is an ignition means serving as a switch for supplying an electric current to the squibs shown at 21 to 24 for ignition.
It operates according to the instructions from the controller shown in.

The safing sensor 3 is a mechanical switch that operates by deceleration due to a direct collision, in addition to an instruction from the controller 4.

When a collision occurs, the controller 4 determines, based on a signal from a crash sensor (not shown), whether it is a collision impact or a bad road impact. Drive and supply current to the squib for ignition. At this time, the safing sensor 3 is set so that the contacts are closed when a deceleration equivalent to a collision is actuated, so that the contacts are simultaneously turned on and current is supplied to the squib when the ignition means 11 to 14 are turned on. Is configured.

With this configuration, even if the controller 4 erroneously generates a drive signal, it is possible to prevent erroneous explosion because the safing sensor 3 is off.

Assuming that a collision has occurred, the impact is detected by a crash sensor (not shown), and the controller 4 determines whether or not the collision occurs. If the collision is determined, the ignition means 11 to 14 are driven sequentially or simultaneously. It gives a signal and supplies current to the squib to ignite it. At this time, if the ignition means 11 has a short circuit failure, the resistance value of the squib 21 is almost 0 ohms, and therefore the ignition means 12 ...
Even if the switch 14 is turned on, the current is concentrated on the squib 21, and the squibs 22 to 24 cannot be supplied with a sufficient current to explode, resulting in a non-explosion problem.

Therefore, in such a case, the ignition means 12 to 14 are turned on to supply the current to the normal squibs 22 to 24 before the current is supplied to the squib 21 having a short circuit failure, that is, before the ignition means 11 is turned on. After supplying and igniting, the ignition means 11 is turned on to supply a current to the squib 21 having a short circuit failure, so that the current does not concentrate on the squib 21 having a short circuit failure and normal squibs 22 to 24 are obtained. Sufficient current can be supplied to ignite, and the current can also be applied to the squib that has a short circuit failure to ignite the location of the short circuit failure.

Here, a method of detecting a short circuit will be described.
Reference numerals 51 to 54 in FIG. 2 are means for differentially detecting the voltages at the upper and lower ends of the squibs 21 to 24, and show the voltage between the upstream and downstream of the squibs 21 to 24 when the ignition means 11 to 14 are ON. It is determined that the squibs 21 to 24 are normal when the voltage difference is equal to or more than a certain value, and that the short circuit failure occurs when the voltage difference is less than or equal to a certain value.

The actual ignition control will be described with reference to FIG. FLAG that appears here is, for example, 8bit
It is a memory that can be rewritten in 1-bit units, and uses the lower 4 bits. The 0th bit is the abnormality flag for the squib 21,
When it is 0, that is, in a clear state, it is normal, and when it is 1, that is, in a set state, it indicates a short-circuit fault. Similarly, the 1st bit is the abnormality flag for the squib 22, the 2nd bit is the abnormality flag for the squib 23, the 3rd bit is the abnormality flag for the squib 24, and 0 is normal for each bit and 1 indicates a short-circuit fault. .

First, in STEP 1 to STEP 12, the failure determination of each squib is performed. When the squib 21 has a short circuit failure, the FLAG
Set bit0 (STEP2), and clear (STEP3) when normal. Similarly, in the case of the squib 22, FLAG at the time of short-circuit failure
Set bit 1 of (STEP5), clear bit 1 of FLAG at normal time (STEP6), and set bit 2 of FLAG at short circuit failure (STEP8) for squib 23, FLAG at normal time
Bit 2 of is cleared (STEP 9), in the case of squib 24, bit 3 of FLAG is set at the time of short circuit failure (STEP 11)
Clear bit 3 of LAG (STEP 12).

Then, the top 4 FLAGs that are not used
Clear the bit (STEP13) and determine which bit of FLAG is set, that is, which squib has a short circuit fault, and which squib it is (STEP14
Or later).

First, consider the case where only one of the four squibs has a short circuit failure. When only the squib 21 has a short circuit fault, only bit 0 of FLAG is set, so the value of FLAG is 1 (STEP 14). At this time, the short-circuited squib 21 is ignited at the end so that the other squibs 22-23 are first ignited and then the squibs 21 are ignited (STEP 15-STEP 16).
At this time, the three operations in STEP 15 may be simultaneous or time-sequential. Similarly, when only the squib 22 has a short circuit failure, only bit 1 of FLAG is set, so F
The value of LAG is 2 (STEP 17). At this time,
The short-circuited squib 22 is ignited at the end so that the other squibs 21, 23 and 24 are first ignited and then the squib 22 is ignited (STEP 18 to STEP 19). At this time, the three operations in STEP 18 may be simultaneous or time-sequential as in the case of the squib 21. When only the squib 23 has a short-circuit fault, only bit 2 of FLAG is set, so the value of FLAG is 4 (STEP 20). At this time, the squib 2 which has a short circuit failure
3 is the last squib to ignite at the very end
First, the squibs 23 are ignited after first igniting 1, 22, 24 (STEP 21 to STEP 22). At this time, the three operations in STEP 21 may be simultaneous or time-series, as in the case of the squib 21. If only squib 24 has a short circuit fault, only bit 3 of FLAG is set, so F
The value of LAG is 8 (STEP 23). At this time,
The short-circuited squib 24 is ignited last, so that the other squibs 21 to 23 are first ignited and then the squib 24 is ignited (STEP 24 to STEP 25). At this time ST
As with the squib 21, the three tasks in EP24 can be simultaneous or in chronological order. By doing the above, when only one of the four squibs has a short circuit failure, the current does not concentrate on the short circuited squib and three normal squibs are ignited. You can

A case where two or more squibs have a short circuit fault will be described with reference to FIG. 2 squibs
If there are more than one short circuit fault, proceed to STEP26. FL
If bit 0 of AG is cleared, the squib 21 is normal and is ignited (STEP 27). If bit0 of FLAG is not cleared, that is, if there is a short circuit failure, squib 2
Do not ignite 1 and proceed to the next STEP. FLAG bi
If t1 is cleared (STEP28), the squib 22 is normal and is ignited (STEP29). If bit 1 of FLAG is not cleared, that is, if a short circuit occurs, the squib 22 is not ignited and the process proceeds to the next STEP. FLA
If bit 2 of G is cleared (STEP30), squib 2
Since 3 is normal, it is ignited (STEP 31). FLAG bi
If t2 is not cleared, that is, when a short circuit failure occurs, the squib 23 is not ignited and the process proceeds to the next STEP.
If bit 3 of FLAG is cleared (STEP32), the squib 24 is normal and is ignited (STEP33). FLAG
If bit 3 of is not cleared, that is, when a short circuit failure occurs, the squib 24 is not ignited and the process proceeds to the next STEP. At this point, all normal squibs are ignited, so ignite all squibs, including the last squib that was ignited (STEP 34). By doing this, current will flow to the squib that has a short circuit failure because it will be the last time to flow current, and there is a problem that sufficient current to ignite a normal squib cannot flow. It becomes possible to prevent it.

Up to now, the four squib system has been described. However, the system is simplified, and one driver squib for the driver's seat and two squibs for the passenger seat, as well as a system for the driver's seat are used. Needless to say, the present invention can be applied to a system including two squibs, one squib for the front passenger seat and one squib for the driver's seat or one squib for the driver's seat and one squib for the driver's seat pretensioner seat belt. Further, it is also possible to omit the safing sensor 3 and configure the system with only a crash sensor (not shown) and the controller 4, and even in that case, the present invention can be applied.

[0020]

According to the present invention, even if the squib has a short circuit failure without adding a special circuit and increasing the cost, it is possible to prevent the current from concentrating on the short circuit squib. However, it is possible to supply a sufficient current to the normal squib to ignite it.

[Brief description of drawings]

FIG. 1 is a flowchart showing the control content of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

3 ... Safing sensor, 4 ... Controller, 11-1
4 ... squib ignition means, 21-24 ... squib, 31,
111, 121, 131, 141 ... Resistors, 51-54 ...
Differential detection means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hayato Sugawara 2477 Kashima Yatsu, Katsuta-shi, Ibaraki Pref. 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Ken Funazaki 2520, Takata, Katsuta-shi, Ibaraki Prefecture Hitachi, Ltd. Automotive Equipment Division (72) Inventor Yoshiya Takano 2520 Takaba, Takata, Ibaraki Prefecture, Ltd. Inside Automotive Equipment Division, Hitachi, Ltd. (72) Inventor Akiyama ▲ Yoshi ▼ Takata, Katsuta, Ibaraki Prefecture Address 2520 Hitachi Automotive Systems Division

Claims (3)

[Claims] Claims: 1. Two or more airbags, a squib for igniting the airbags, an ignition means for igniting the squibs, a crash sensor for detecting acceleration upon collision of the vehicle, and the crash. A controller that determines a collision based on a signal from a sensor and issues an ignition instruction to an ignition means for igniting the squib, an operation detecting means that detects a voltage difference between an upper end and a lower end of the squib, and the squib. It is composed of a safing sensor which operates a switch by the acceleration at the time of a collision with a power supply, and the controller determines that the squib has a short circuit failure based on a signal from the operation detecting means. Even if one or more short-circuit faults occur, all normal squibs can be supplied with enough current to ignite them. Vehicle airbag device, characterized in that. 2. The vehicle airbag device according to claim 1, wherein the vehicle airbag device comprises one or more airbags and one or more pretensioner type seat belts instead of two or more airbags. 3. The airbag device for a vehicle according to claim 1, wherein a safing sensor that is switch-operated by acceleration at the time of collision is not used.