JPH09220998A - Occupant protecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To share a backup capacitor between a main occupant protecting device and an auxiliary occupant protecting device, by inserting a switch circuit turned off by a first control circuit at least when a diagnosis of backup capacitor failure is conducted by the first control circuit into a power source line and by electrically separating the main occupant protecting device from the auxiliary occupant protecting device. SOLUTION: In the capacity diagnosis of a backup capacitor 23, just after a switch is turned on, a switch circuit 32 is turned off via a signal line Y to thereby stop and auxiliary occupant protecting device 45 from acting as the load of the backup capacitor 23; that is, a main occupant protecting device are electrically separated from the auxiliary occupant protecting device 45. Then, a switching transistor 31 is turned on to discharge a charge charged in the backup capacitor 23 via a resistance 30. A microcomputer 25 reads the amount of change in specified time of terminal voltage of the backup capacitor 23 at that instant and calculates a static capacity, thereby conducting a diagnosis of the capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant protection device including a plurality of airbags for protecting an occupant in the event of a vehicle collision.

[0002]

2. Description of the Related Art A conventional occupant protection device of this type will be described with reference to FIG. The booster circuit 3 boosts the input voltage from the battery 1 supplied via the ignition switch 2 and charges the backup capacitor 5 via the resistor 4. The charged electric charge is stored in the microcomputer 1
1 is turned on when it is determined to be a serious collision based on the acceleration signal supplied from the acceleration sensor 10, the detonator 8 and the mechanical acceleration switch 9 (at this time, in the ON state) via the diode 6 are turned on. However, it is normally discharged in the off state) in series, and the detonator 8 ignites a gunpowder (not shown) to deploy the airbag. The mechanical acceleration switch 9 has a structure disclosed in Japanese Patent Application No. 5-351470 filed by the present applicant.

Further, the microcomputer 11 has a failure diagnosing function, and when the capacity of the backup capacitor 5 is diagnosed, the transistor 13 is turned on for a predetermined time to discharge the electric charge charged in the backup capacitor 5 through the resistor 12. When the change amount of the terminal voltage of the backup capacitor 5 at that time is read and whether the electrostatic capacity of the backup capacitor 5 is a specified value is diagnosed and it is determined that there is an abnormality (out of the specified value), The occupant is notified using an alarm device such as a lamp (not shown).

However, the occupant protection device as described above has been developed to protect the occupant in the event of a collision from the front of the vehicle, and has recently been used to protect the occupant also in the event of a collision from the side of the vehicle. Development is underway to try. In that case, the occupant protection device unit from the front and the occupant protection device unit from the side may be provided as separate units, but it is usually considered to share the circuit as a common means for cost reduction. Therefore, the configuration will be described below with reference to FIG.

That is, in FIG. 5, a unit indicated by reference numeral 14 is a main occupant protection device, which is for protecting an occupant against a collision from the front of the vehicle, and its configuration is the same as that shown in FIG. It has the same configuration. Reference numeral 15
The unit indicated by is a sub occupant protection device, which is for protecting the occupant against a collision from the side of the vehicle. The power of the sub occupant protection device 15 is supplied by a power supply line such as a harness indicated by reference numeral 16. The main occupant protection device 14 is connected so that power is supplied from the backup capacitor 5.

The auxiliary occupant protection device 15 (the one on the right side of the one shown by the broken line frame in FIG. 5) is attached to the door of the vehicle or in the vicinity thereof, and reference numeral 10 'therein.
Is a lateral acceleration sensor, and a longitudinal acceleration sensor 10
This is the same as the above-mentioned one, but is attached to the vehicle by changing the detection direction so that the acceleration from the left and right direction of the vehicle can be detected.

Reference numeral 11 'denotes a microcomputer having a collision judgment function equivalent to that of the microcomputer 11,
When a collision is determined based on the acceleration signal from the lateral acceleration sensor 10 'that detects an acceleration signal generated in the vehicle left-right direction, and if a serious collision is determined, a switch circuit 7' (equivalent to the switch circuit 7 Things) to turn on. In addition, 8'is a detonator equivalent to the detonator 8, 9'is a mechanical acceleration switch equivalent to the mechanical acceleration switch 9, 17 is a constant voltage circuit, and the booster circuit 3 (or the booster circuit 3 via the power supply line 16 (or It receives an output from the backup capacitor 5) and supplies a constant voltage to each circuit constituting the auxiliary passenger protection device 13.

That is, since the main occupant protection device 14 performs the same operation as that shown in FIG. 4, a detailed description thereof will be omitted, but the auxiliary occupant protection device 15 does not include the booster circuit 3 (or the booster circuit 3 of the main occupant protection device 14). In addition to receiving the boosted voltage from the backup capacitor 5) via the power supply line 16, the auxiliary occupant protection device 15 detects the acceleration due to the collision from the side of the vehicle by the lateral acceleration sensor 10 ', and based on the detection signal, When the computer 11 'judges that it is a serious accident, the switch circuit 7'is turned on to control the main occupant protection device 1
The electric power charged in the backup capacitor 5 of No. 4 is caused to flow in series to the detonator 8'and the acceleration switch 9 ', and the explosive is ignited to deploy the airbag. Note that, normally, both switch circuits 7 and 7'are not turned on at the same time, that is, there is no simultaneous collision from the front and the left and right of the vehicle.
It doesn't have to be bigger than the ones.

[0009]

However, in the main occupant protection device 14 of the occupant protection device shown in FIG. 5, if the capacity of the backup capacitor 5 is diagnosed immediately after the power is turned on, the auxiliary occupant protection device 15 shown in FIG. The constant voltage circuit 17 of FIG. 4 becomes a load of the booster circuit 3, and a current flows into this load. Therefore, the backup capacitor 5 shown in FIG.
With the backup capacitor 5 shown in FIG. 5, the discharge time constant becomes indefinite due to the load, and the accuracy of the capacity diagnosis is poor with the same diagnosis algorithm (program), so it was considered necessary to change the capacity diagnosis program. .

Therefore, the present invention has been made to solve the above problems, and is commonly used by electrically disconnecting the main occupant protection device and the sub occupant protection device during the capacity diagnosis of the backup capacitor. The purpose is to do.

[0011]

SUMMARY OF THE INVENTION An occupant protection system according to the present invention is a backup capacitor charged by a DC power source, a series circuit connected between terminals of the backup capacitor, which is composed of at least a switch circuit and a squeeze, and is accompanied by a collision. Main occupant protection device having a function of performing a collision determination based on an acceleration signal generated as a result of the determination and performing an ON control of the switch circuit, and at least a diagnostic function of performing a failure diagnosis of the backup capacitor. A constant voltage circuit to which electric power is supplied from a backup capacitor of the main occupant protection device through a power supply line, and a second control circuit which is fed from the constant voltage circuit and inputs an acceleration signal different from the acceleration signal. A sub-occupant protection device provided at least, the power line, at least the first control circuit At the time of failure diagnosis of the backup capacitor that consists by inserting the switch circuit is turned off controlled by the first control circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1. The first embodiment according to the present invention will be described with reference to FIG. First, the main occupant protection device 35 will be described. That is, 21 is a booster circuit, which boosts the input voltage from the battery 1 supplied via the ignition switch 2 to charge the backup capacitor 23 via the resistor 22, and at the same time, the switch circuit provided on the power supply line 36. The boosted voltage is supplied to the auxiliary occupant protection device 45 via the resistor 32 and the resistor 34 in series. Reference numeral 24 denotes a longitudinal acceleration sensor for detecting acceleration generated in the longitudinal direction of the vehicle. An acceleration signal as a detection signal is supplied to a microcomputer 25 described later. This microcomputer 25 has a collision determination function, and when it determines a serious collision based on the acceleration signal supplied from the longitudinal acceleration sensor 24, the switch capacitor 26 is turned on to charge the backup capacitor 23. The electric charge is discharged through the discharging diode 27, and an ignition current is passed in series to the detonator 28 and the mechanical acceleration switch 29. It goes without saying that the mechanical acceleration switch 29 is turned on at this time.

Further, the microcomputer 25 has a function of diagnosing the backup capacitor 23, the detonator 28, and the like. Among them, in the capacity diagnosis of the backup capacitor 23, immediately after the ignition switch 2 is turned on, a signal line Y is used. Turning off the transistor 32, the charge of the backup capacitor 23 is
The auxiliary occupant protection device 45 should not be discharged as a dark current in each circuit, that is, the auxiliary occupant protection device 45, which will be described later, has no relation to act as a load of the backup capacitor 23. After the occupant protection device 45 is electrically disconnected from the occupant protection device 45, the switching transistor 31 is turned on, the electric charge charged in the backup capacitor 23 is discharged through the resistor 30, and the terminal voltage of the backup capacitor 23 at that time is The microcomputer 25 reads the amount of change during a predetermined period of time, performs capacitance diagnosis by calculating the electrostatic capacitance, and when it determines that there is an abnormality, informs the occupant using an alarm device such as a lamp (not shown).

If the microcomputer 25 judges the disconnection diagnosis of the detonator 28 based on the voltage and the voltage difference between the both ends of the detonator 28, and if it is judged that there is a disconnection, it is shown in the same manner as above. Notify the occupant using an alarm device such as a lamp that is not operated. Further, the microcomputer 25 inputs various diagnostic signals from the auxiliary occupant protection device 45 through the signal line Z to perform the same diagnosis as described above.
At that time, needless to say, after transmitting a request signal from the first communication circuit 33 to the auxiliary passenger protection device 45 via the signal line X, various diagnostic signals are transmitted from the microcomputer 25 'of the auxiliary passenger protection device 45. That's a good thing. In addition, reference numeral 34 in the figure is a resistor interposed between the switch circuit 32 and the power supply line 36.

Next, the auxiliary passenger protection device 45 will be described. Reference numeral 24 'denotes the same acceleration sensor as the longitudinal acceleration sensor 24, which has a different detection direction from that of the longitudinal acceleration sensor 24 and is attached so as to detect the lateral acceleration of the vehicle. It is a lateral acceleration sensor supplied to the computer 25 '. Like the microcomputer 25, the microcomputer 25 'has a collision determination function, and based on an acceleration signal supplied from the lateral acceleration sensor 24' and a switch signal supplied from an acceleration switch 40 described later. If the magnitude of the collision from the side of the vehicle is judged and if it is judged as a serious collision, the switch circuit 26 'is turned on to control the ignition current from the backup capacitor 23 of the main occupant protection device 35 to the detonator 28' via the power supply line 36. To supply.

The microcomputer 25 'has a diagnostic function similarly to the microcomputer 25, diagnoses disconnection of the detonator 28', etc., and is supplied from the first communication circuit 33 via the power supply line 36. Based on the request signal, this diagnosis result is sent to the microcomputer 25 of the main occupant protection device 35 via the second communication circuit 33 '(the same as the first communication circuit 33), the power supply line 36, and the signal line Z.
To supply. The acceleration switch 40 is composed of a semiconductor acceleration sensor and a comparison circuit for inputting the detection output of the semiconductor acceleration sensor, and outputs a switch signal when the output from the semiconductor acceleration sensor exceeds the reference value of the comparison circuit. 32 '
Is a switching transistor, which is inserted between the output side terminal of the ignition switch 2 and the output terminal of the main occupant protection device 35, is turned off by the microcomputer 25 when the switching transistor 32 is on, and is turned off. Sometimes it is turned on.

A switching transistor 41 such as a field effect transistor is turned on / off by an output signal of the second communication circuit 33 'and outputs various diagnostic signals. A switching transistor equivalent to this switching transistor 41 is also connected to the output side of the first communication circuit 33 to form a similar circuit. A resistor 42 is interposed between the switching transistor 41 and the power supply line 36, and is connected in series with the resistor 34 via the power supply line 36 so that the voltage on the anode side of the backflow prevention diode 43 is a switching transistor. When 41 is turned on (or when a switching transistor (not shown) formed on the output side of the first communication circuit 33 is turned on), the voltage does not become 0 level and is maintained at a constant voltage, and is always constant as described below. An input voltage can be supplied to the voltage circuit 44. The constant voltage circuit 44 always receives the input voltage and supplies electric power to each circuit forming the auxiliary passenger protection device 45.

The power line 36 is connected to the main occupant protection device 3.
When the communication is performed between the vehicle 5 and the auxiliary occupant protection device 45, the voltage waveform is as shown in FIG. That is, in FIG. 2, the voltage V1 is a value obtained by dividing the output voltage V3 of the booster circuit 21 when the switching transistor 41 is turned on by the resistors 13 and 42, and the voltage V2 is a voltage when the switching transistor 41 is turned off. , Resistance 34
Depends on the value of.

Next, the operation of the above configuration will be described. When the diagnostic function operates, the ignition switch 2 is turned on, the microcomputer 25 of the main occupant protection device 35 starts to operate, and when the passenger compartment diagnosis is performed, the microcomputer 25 turns off the switch circuit 32 via the signal line Y. At the same time, the microcomputer 25 turns on the switch circuit 32 ′ via the signal line Y ′ to rapidly charge the power supply capacitor of the constant voltage circuit 44 of the auxiliary occupant protection device 45, and the auxiliary occupant protection device 45 to the main occupant protection device. Operate at the same time as 35.
After that, the microcomputer 25 turns on the switching transistor 31 for a predetermined time, discharges the sufficiently charged backup capacitor 23 through the resistor 30, and the backup capacitor 23 at that time is discharged.
When the microcomputer 25 reads the terminal voltage of the above, the microcomputer 25 determines whether or not the electrostatic capacitance has a specified value from the voltage change of the terminal voltage of the backup capacitor 23, and when an abnormality occurs, activates an alarm device. Let me know.

After that, the switch circuit 32 is turned on and the switch 32 'is turned off, and the first communication circuit 3
3. A diagnosis request signal is supplied to the microcomputer 25 'of the auxiliary occupant protection device 45 via the power supply line 36. The microcomputer 25 is a main occupant protection device 35.
Of each of the above, for example, a wire breakage of the detonator 28 and a short circuit abnormality are diagnosed. Microcomputer 2 that received the diagnostic request signal
5'is each part in the auxiliary passenger protection device 45, for example, a detonator 28 '.
Of the power supply line 3 by reading the terminal voltage of the second communication circuit 33 ′ and turning on / off the switching transistor 41 according to the output of the second communication circuit 33 ′.
6 to the microcomputer 25 of the main occupant protection device 35 via the signal line Z, and the microcomputer 25 diagnoses.

When the collision determination function operates When the vehicle undergoes a frontal collision such as a rear-end collision after the above-mentioned various diagnoses are completed (or when the diagnosis is not performed), the mechanical acceleration switch 29 of the main occupant protection device 35 is activated. When the microcomputer 25 is turned on, the microcomputer 25 further activates the longitudinal acceleration sensor 2
When it is determined that a serious collision has occurred based on the acceleration signal from 4,
The microcomputer 25 controls the switch circuit 26 to be turned on so that the charge stored in the backup capacitor 23 is supplied to the detonator 28 through the discharging diode 27 to inflate the airbag or the like to protect the occupant from a frontal collision. However, at this time, since the acceleration acts in the front-back direction of the vehicle, the left-right acceleration sensor 2 of the auxiliary occupant protection device 45.
No signal is output from 4'and the acceleration switch 40,
No ignition current is supplied from the backup capacitor 23 to the detonator 28 '.

When the vehicle is laterally collided,
Since the mechanical acceleration switch 29 of the main occupant protection device 35 is not turned on and the front-rear direction acceleration sensor 24 does not output an acceleration signal having a magnitude corresponding to the acceleration signal associated with the forward collision, the primer 28 is ignited. No current is supplied.

On the other hand, if the microcomputer 25 'of the auxiliary occupant protection device 45 determines that a serious collision occurs based on the switch signal from the acceleration switch 40 and the acceleration signal from the lateral acceleration sensor 24', the microcomputer 25 '. Turns on the switch circuit 26 'to charge the backup capacitor 23 with the power line 3
6 to a primer 28 'to deploy the airbag to protect the occupant from side collisions.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described based on FIG. In the second embodiment,
Microcomputer 25 'for the one shown in FIG.
The collision determination function performed in the above is transferred to the microcomputer 25 of the main occupant protection device 35, and the auxiliary occupant protection device 45
The switch circuit 26 ′ of No. 1 is transferred to the main occupant protection device 35, and the detonator 28 ′ of the sub occupant protection device 45 is not provided as a unit, but is provided on the door, seat, etc. It was something that was designed.

Along with this, the microcomputer 25 'makes a second communication between the signal after processing the acceleration signal from the lateral acceleration sensor 24' and the signal after processing the switch signal from the acceleration switch 40. Circuit 33 '
Needless to say, the signal is constantly output to the microcomputer 25 of the main occupant protection device 35 and transmitted to the microcomputer 25 of the main occupant protection device 35 for collision determination, and the switch circuit 26 'is turned on as necessary.

[0026]

As described above, according to the present invention, the capacity diagnosis of the backup capacitor of the main occupant protection device can be surely diagnosed regardless of whether the auxiliary occupant protection device is attached to the main occupant protection device. The effect is that it can be shared among different vehicle types.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an occupant protection device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram of a power supply line 36 in FIG.

FIG. 3 is a circuit block explanatory diagram of a second embodiment of the occupant protection system according to the present invention.

FIG. 4 is a circuit diagram of a conventional example of the present invention.

5 is a circuit block explanatory diagram of a prior art example that can be easily conceived from the conventional occupant protection device shown in FIG.

[Explanation of symbols]

 24 longitudinal acceleration sensor 24 'lateral acceleration sensor 25, 25' microcomputer 26, 26 ', 32 switch circuit 28, 28' detonator 33, 33 'communication circuit 34, 42 resistor 31, 41 switching transistor 40 acceleration switch

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayuki Kishi 2-1910 Nisshin-cho, Omiya-shi, Saitama Kansei Co., Ltd. (72) Shinichiro Tsurushima, Inc. 2-1910 Nisshin-cho, Omiya-shi, Saitama Kansei Co., Ltd.

Claims (1)

[Claims] 1. A backup capacitor charged by a DC power source, a series circuit connected between its terminals, comprising at least a switch circuit and a squeeze, and collision determination based on an acceleration signal generated with the collision, A main occupant protection device having a function of controlling ON of a switch circuit and at least a first control circuit having a diagnostic function of performing a failure diagnosis of the backup capacitor, and a power supply line from the backup capacitor of the main occupant protection device. A sub-occupant protection device including at least a constant voltage circuit supplied with power via the constant voltage circuit and a second control circuit fed from the constant voltage circuit to input an acceleration signal different from the acceleration signal; The line, at least during the failure diagnosis of the backup capacitor by the first control circuit, Occupant protection apparatus characterized by comprising by inserting the switch circuit is turned off controlled by a control circuit.