JP3859825B2 - Crew protection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an occupant protection device provided with a plurality of airbags for protecting an occupant in the event of a collision accident from the front and side of a vehicle, for example.
[0002]
[Prior art]
This type of occupant protection device, that is, a driver's seat airbag unit (main control circuit) 1, a driver's seat side airbag unit (sub control circuit) 2, and a passenger's seat side that share a power line as a signal line and perform multiplex communication with each other. A description will be given based on an occupant protection device (a device related to this is currently filed and unpublished) shown in FIG.
First, the driver's seat airbag unit 1 will be described.
That is, 6, 7, and 8 are first, second, and third booster circuits, each boosting the input voltage from the battery 4 supplied via the ignition switch 5 and connected to the respective output terminals. 1, the second and third backup capacitors 9, 10 and 11 are charged. Among the booster circuits 6, 7, and 8, the boosted voltage output from the third booster circuit 8 is supplied to the driver side airbag unit via the first switch circuit 12 and the resistor 13 inserted in series with the power supply line 14. 2 and the passenger side airbag unit 3 are supplied as a power supply voltage.
The second and third booster circuits 7 and 8 are electrically set to the same capacity, while the first booster circuit 6 is set to be twice as large as the second and third booster circuits 7 and 8. Has been. Similarly, the second and third backup capacitors 10 and 11 are set to the same capacity, whereas the capacity of the first backup capacitor 9 is set to be twice that of the other backup capacitors 10 and 11. Yes.
Reference numeral 15 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 16 which will be described later.
[0003]
The microcomputer 16 has a collision determination function, and charges the backup capacitor 9 by turning on the second switch circuit 17 when it is determined that the collision is serious based on the acceleration signal supplied from the longitudinal acceleration sensor 15. The charged electric charge is caused to flow as an ignition current in series through the detonator 18 and the mechanical acceleration switch 19 to deploy the airbag attached to the handle.
[0004]
The microcomputer 16 has a failure diagnosis function such as the backup capacitors 9, 10, 11, detonators 18, 21, 23, mechanical acceleration switch 19, etc., of which the capacity diagnosis of the backup capacitors 9, 10, 11 is performed. Immediately after the ignition switch 5 is turned on, the first switch circuit 12 is turned off via the signal line Y, and the charging charges of the backup capacitors 9, 10 and 11 are forcibly discharged using a circuit (not shown). When the microcomputer 16 reads the amount of voltage change of the terminal voltage of the backup capacitors 9, 10, 11 during a predetermined time, thereby calculating the capacitance and performing capacitance diagnosis, and determining that the capacitance value is abnormal In this case, a warning device such as a lamp is used to inform the passenger.
[0005]
Further, the disconnection diagnosis of the detonator 18, 21, 23 and mechanical acceleration switch 19 is determined by the microcomputer 16 based on the terminal voltages of the detonator 18, 21, 23 and mechanical acceleration switch 19 and the voltage difference between them. However, if it is determined that the wire is broken or the like, the occupant is notified using an alarm device such as a lamp in the same manner as described above. Further, the microcomputer 16 supplies a request signal to each of the driver's seat and the passenger seat side airbag systems 2 and 3 via the signal line X, the first communication circuit 25, the first switching transistor 26, and the resistor 27, Response signals including various diagnostic signals, collision determination signals, and the like from the driver seat and passenger side airbag systems 2 and 3 in response to the request signal are input via the signal line Z. Reference numeral 29 is a circuit system power supply. The input terminal is connected to the output side of the ignition switch 5 and is connected to the emitter terminal of the switching transistor 28 to supply a constant voltage to the microcomputer 16 and the microcomputer 16 is ignited. When it is determined that the switch 5 is turned off or an equivalent disconnection has occurred, the switching transistor 28 is turned on to supply power from the backup capacitor 9.
[0006]
Next, although the driver's seat side airbag system 2 will be described as a representative side airbag unit, the passenger's seat side airbag unit 3 has the same configuration as this, and a detailed description thereof will be omitted.
Reference numeral 30 denotes the same acceleration sensor as the longitudinal acceleration sensor 15, which has a detection direction different from that of the longitudinal acceleration sensor 15 and is attached so as to detect the acceleration in the lateral direction of the vehicle. 31.
[0007]
The microcomputer 31 has a collision determination function similar to the microcomputer 16 and determines the size of the collision based on the acceleration signal supplied from the lateral acceleration sensor 30 and the switch signal from the acceleration switch 32. The determination result is sent to the power supply line 14 through the second communication circuit 33, the second switching transistor 34, and the resistor 35 in series as a response signal together with a diagnosis result described later.
[0008]
The power line 14 has a voltage waveform as shown in FIG. 3 when the driver's seat airbag unit 1 is performing multiplex communication with the driver's seat and front passenger seat side airbag units 2 and 3.
That is, in FIG. 3, the voltage V1 is the output voltage V3 of the booster circuit 6 when the switching transistors 26 and 34 (or the switching transistor 44 of the passenger side airbag unit 3) are turned on by the resistors 13 and 35 (or 45). The resistance is divided, and the voltage V2 is a voltage when the switching transistors 26 and 34 (or 44) are turned off, and the value of the resistor 13 is determined.
In addition, power is supplied from a constant voltage circuit (not shown) that is supplied with power from the power supply line 14 and outputs a constant voltage to each circuit portion constituting each of the driver's seat and passenger side airbag units 2 and 3. It goes without saying that it is supplied.
[0009]
Next, the operation of the above configuration will be described.
(1) When the ignition switch 5 is turned on when the diagnostic function is activated, the first, second and third booster circuits 6, 7 and 8 are supplied with power from the battery 4, and the first, The second and third backup capacitors 9, 10, 11 are charged, the microcomputer 16 of the driver airbag unit 1 starts to operate, the first switch circuit 12 is turned off via the signal line Y, The charged first, second and third backup capacitors 9, 10, 11 are forcibly discharged in order for a certain time, and the change amount of the terminal voltage of each backup capacitor 9, 10, 11 at that time is determined by the microcomputer. 16 reads the capacitance to determine whether it is a specified value or not, and if an abnormality occurs, activates an alarm device (not shown) to notify . In addition, a diagnosis of disconnection of the detonators 18, 21, and 23 is performed, and an alarm device (not shown) is also activated when it is determined that there is a failure.
Thereafter, the first switch circuit 12 is turned on, and a request signal is supplied to the microcomputer 31 of the driver side airbag unit 2 via the first communication circuit 25 and the power line 14, but the request signal is received. The microcomputer 31 reads the terminal voltage of each part in the driver side airbag unit 2, for example, the lateral acceleration sensor 30, and turns on and off the switching transistor 34 according to the output of the second communication circuit 33. Through the signal line Z to the microcomputer 16 of the driver's seat airbag unit 1 to make a diagnosis, and as a result, when it is determined that there is a failure, the alarm device is activated in the same manner as described above. .
[0010]
(2) When the collision determination function is activated After the various diagnoses are completed (or not performed), when the vehicle has a forward collision such as a rear-end collision, the mechanical acceleration switch 19 of the driver airbag unit 16 Is turned on, and when the microcomputer 16 determines a serious collision based on the acceleration signal from the longitudinal acceleration sensor 15, the microcomputer 16 turns on the second switch circuit 17 to charge the first backup capacitor 9. Electric charge is passed through the detonator 18 to deploy a driver's seat airbag and the like to protect the occupant from a forward collision.
[0011]
On the other hand, when the microcomputer 31 of the driver's seat side airbag unit 2 determines that a serious collision has occurred based on the switch signal from the acceleration switch 32 and the acceleration signal from the lateral acceleration sensor 30, the microcomputer 31 uses the data as a response signal. The computer 31 supplies the microcomputer 16 via the switching transistor 34 and the power supply line 14. As a result, the microcomputer 16 turns on the third switch circuit 20 to supply the charge charged in the backup capacitor 10 to the detonator 21 and deploys the air bag provided on the seat to remove the occupant from the side collision. Protect.
[0012]
Similarly, when the microcomputer 41 of the passenger side airbag unit 3 determines a serious collision based on the switch signal from the acceleration switch 42 and the acceleration signal from the lateral acceleration sensor 40, the microcomputer uses the data as a response signal. The computer 41 supplies the microcomputer 16 via the switching transistor 44 and the power supply line 14. As a result, the microcomputer 16 controls the fourth switch circuit 22 to turn on, supplies the charge charged to the backup capacitor 11 to the detonator 23, deploys the airbag provided on the seat, and removes the occupant from the side collision. Protect.
[0013]
[Problems to be solved by the invention]
However, in such a configuration as described above, each detonator has its own backup capacitor, and both side airbag units are configured for backup as one of the backup capacitors. Therefore, the common backup capacitor having a capacitance value twice that of other backup capacitors is used.
[0014]
Therefore, the shape of this commonly used backup capacitor is large, and if it is not carefully placed on the circuit board from the beginning, it will cause the board shape to become unnecessarily large, and the booster circuit connected to it will be another booster circuit. It had to have twice the electric capacity.
[0015]
Therefore, the present invention has been made paying attention to the above-mentioned problems, and by reducing the electric capacity of the booster circuit, reducing the shape of the electronic component to be used, and reducing the number of backup capacitors, it is compact. The purpose is to reduce costs.
[0016]
[Means for Solving the Problems]
Occupant protection device according to the present invention, igniting the first detonator in electric charge of the first backup capacitor charged by the first booster circuit and the boost voltage that steps up the voltage fed from the battery, the first A second booster circuit that is connected in parallel to the booster circuit and boosts the voltage supplied from the battery, and a second backup capacitor that is charged by the boosted voltage is used to develop the driver side airbag. Control means for selectively igniting the second detonator and the third detonator for deploying the passenger side airbag, a main control circuit having a constant voltage circuit fed by the battery, and an output of the constant voltage circuit as a power source A driver side airbag unit and a passenger side airbag unit, the main control circuit, and the driver side airbag unit And a communication circuit that performs multiplex communication with the passenger side airbag unit and the passenger side airbag unit, and the main control circuit expands the driver side airbag when receiving a response signal from the driver side airbag unit. A detonator is ignited, and when a response signal is received from the passenger seat side airbag unit, a third detonator for igniting the passenger seat side airbag is ignited.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIG.
In FIG. 1, the same or equivalent components as those already described in FIG. 2 are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions will be described below.
That is, in FIG. 1, the emitter terminals which are the input terminals of the third and fourth switch circuits 20 and 22 shown in FIG. 2 are commonly connected, and one of the second or third backup capacitors 10 and 11 has a large capacitance. The backup capacitor 11 is deleted and shared, and is indicated by reference numeral 50. In FIG. 2, power is supplied from the battery 4 to the both side airbag units 2 and 3 via the ignition switch 5, the third booster circuit 8, the first switch circuit 12, the resistor 13, and the power supply line 14. However, in FIG. 1, the third booster circuit 8 and the constant voltage circuit 51 are connected between the output side of the ignition switch 5 and the input terminal of the resistor 13.
[0018]
Thereby, the backup capacitor 11 for driving both side airbags 2 and 3 can be omitted as in the prior art.
Further, the booster circuit of the second and third detonators 21 and 23 is only one conventional second booster circuit 7, and the backup capacitor 50 can be shared by one conventional backup capacitor 10, and the capacity thereof is the same as the conventional one. Since the capacitor having the same capacity as the backup capacitor 10 is sufficient, the components of this part can be halved, and the cost of this part can be halved.
The constant voltage circuit 51 increases as a circuit component. However, since the constant voltage circuit 51 is an IC, the shape is small and the exclusive area on the substrate can be small.
[0019]
That is, when the side airbag unit 2 on the driver's seat side is deployed, the microcomputer 16 supplies the ignition current from the backup capacitor 50 to the detonator 21 by turning on the second switch circuit 20.
Further, when the side airbag unit 3 on the passenger seat side is deployed, the microcomputer 16 supplies the ignition current from the backup capacitor 50 to the detonator 23 by turning on the third switch circuit 22.
[0020]
【The invention's effect】
As described above, according to the present invention, the circuit scale can be reduced by reducing the electric capacity of the booster circuit to use low-power electronic components, reducing the capacity of the backup capacitor, and reducing the number. The effect that it can be reduced is exhibited.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a circuit block diagram of a first embodiment of an occupant protection device according to the present invention.
FIG. 2 is a circuit explanatory diagram of a conventional example of the present invention.
3 is a waveform diagram of a power supply line 14 in FIG.
[Explanation of symbols]
15, 30, 40 Acceleration sensor 16, 31, 41 Microcomputer 17, 20, 22 Switch circuit 18, 21, 23 Detonator 25, 33, 43 Communication circuit 13, 27, 35, 45 Resistance 26, 34, 44 Switching transistor 32 , 42 Acceleration switch

Claims (1)

Igniting the battery first detonator in electric charge of the first backup capacitor charged by the first booster circuit (6) and boosted its voltage to boost the voltage fed from (4) (9) (18), A second booster circuit (7) connected in parallel to the first booster circuit (6) to boost the voltage supplied from the battery (4 ) and a second backup capacitor ( 7) charged by the boosted voltage. 50) control means (16) for selectively controlling ignition of the second detonator (21) for deploying the driver side airbag and the third detonator (23) for deploying the passenger side airbag with the charge of 50) , A main control circuit (1) having a constant voltage circuit (51) fed by a battery (4), a driver side airbag unit (2) using the output of the constant voltage circuit (51) as a power source, and A passenger side airbag unit (3), a communication circuit (25) in which the main control circuit (1), the driver side airbag unit (2) and the passenger side airbag unit (3) perform multiplex communication. When the main control circuit (1) receives a response signal from the driver side airbag unit (2), the main control circuit (1) ignites the second detonator (21) that deploys the driver side airbag, and the passenger seat An occupant protection device for igniting a third detonator (23) for deploying the passenger side airbag when receiving a response signal from the side airbag unit (3) .

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