JP3461015B2 - Occupant protection device - Google Patents

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 for activating an occupant protection means for an automobile such as an airbag and a seat belt, and its reliability is improved.

[0002]

2. Description of the Related Art In recent years, automobiles have been equipped with airbags as a device for protecting an occupant from a shock such as a collision.
In addition, the seatbelt protection function of the seatbelt is enhanced by operating the seatbelt in the winding direction when a large impact is applied.

As an airbag actuating device, for example, as disclosed in Japanese Patent Laid-Open No. 51-126633, a power source, a transistor as a switch means, and a filament as an initiator firing device. , A mechanically opened and closed collision detection switch is connected in series, and the collision detection switch is turned on at the time of a collision, while a separately provided piezoelectric element detects the collision to cause the switch to pass through the control circuit. It is known that the means is made conductive so that the filament is energized.

According to this, the filament is energized only when both the collision detection switch and the piezoelectric element detect a collision, and high reliability of the device can be obtained.

[0005]

However, when a collision detection switch that mechanically opens and closes is connected in series to the filament for initiation as described above, for example, the piezoelectric element first detects an impact load and switches the switch means. If the filament is configured to be energized when the collision detection switch is turned on when it is made conductive, a large current is required for the filament at the time of detonation. A large voltage will work. Therefore, arc discharge may occur before the collision detection switch is completely closed, which may damage the contacts.

On the other hand, by arranging a collision detection switch that opens and closes mechanically in the base circuit of the switch means (transistor), the above problem caused by a large voltage acting on the switch is solved. It can be avoided. However, in this case, since the switch means is only provided in the series circuit in which the power source and the filament are arranged, the filament is erroneously energized when the switch means is short-circuited, and the reliability is rather lowered. I will let you.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances relating to an occupant protection device when an impact load such as an air bag or seat belt retractor is applied, and it is an object of the present invention to further improve the reliability of the device. And

[0008]

In order to solve the above problems, the present invention is characterized by having the following configuration.

First, the invention of claim 1 of the present application (hereinafter, referred to as the first
An occupant protection device according to the invention) includes a power source, a contact-type deceleration switch that is turned on based on the deceleration of the vehicle, a non-contact type switch means, and an occupant protection means. In the configuration in which the deceleration switch, the switch means, and the driver of the occupant protection means are connected in series, and the occupant protection means operates based on the ON operation of the deceleration switch and the conduction of the switch means, the switch means is set to P
If it consists of two transistors, NP type and NPN type,
In, provided ON state confirmation means for confirming that the deceleration switch is ON state, and, on condition that at least the ON operation state confirming means confirms the ON state of the deceleration switch, the Switch means
The two transistors that form
It is characterized by comprising control means for outputting a signal and a high signal, respectively .

Further, in an occupant protection system according to a second aspect of the present invention (hereinafter referred to as the second aspect of the invention), the control means in the first aspect of the invention includes the ON operation state confirmation means of the deceleration switch O.
It is characterized in that the switch means is electrically connected on condition that the N operation state is confirmed and that the deceleration sensor provided separately detects deceleration of a predetermined value or more.

[0011]

According to the above construction, in both the first and second aspects of the invention, the switch means will not conduct unless at least the ON operation of the deceleration switch for mechanically opening and closing the ON operation confirming means is confirmed. . Therefore, it is avoided that a large voltage acts on the switch before the deceleration switch is completely closed and an arc discharge is generated in the switch, thereby damaging the contacts. Also, switch means
Is composed of two transistors, PNP type and NPN type.
The two transistors to make them conductive.
-By outputting a high signal and a high signal respectively,
The possibility of operation can be reduced.

According to the second aspect of the invention, the switch means is conductive only when the deceleration switch is surely in the ON operation state and the deceleration sensor detects the deceleration of the predetermined value or more. As a result, erroneous energization of the occupant protection means drive unit can be prevented more reliably.

[0013]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows an electric circuit of an occupant protection system according to this embodiment. This circuit basically comprises a control unit 1 and a battery 2 for supplying power to the control unit 1.
And an ignition switch 4 and fuses 5 and 5 provided on the power supply circuit 3, and an ignition device 6 for an airbag detonator whose energization is controlled by the control unit 1.
6 and the ignition device 7, 7 for the detonator for the seat belt retractor.

In the control unit 1, first and second energizing circuits 13 and 14 are provided in parallel between the booster circuit 11 connected to the power feeding circuit 3 and the ground circuit 12. The first energizing circuit 13 is a mechanical opening / closing type deceleration switch 15 which is closed from the booster circuit 11 side by deceleration of a predetermined value or more, and a plus side transistor 1
6, the airbag ignition devices 6, 6 and the minus side transistor 17 are arranged, and the second energizing circuit 14 is provided.
The positive side transistor switch 18, the seat belt retractor firing devices 7, 7 and the negative side transistor 19 are arranged in the vehicle.

Furthermore, the first and second energizing circuits 13 and 1
4, the first and second capacitors 21,
When 22 is connected and these energizing circuits 13 and 14 are conducted, a large current flows through these energizing circuits 13 and 14 based on the stored voltage of the first and second capacitors 21 and 22, respectively. At the same time, the first and second capacitors 21, 22 are charged between the first and second energizing circuits 13, 14 and the power supply circuit 3 at the time of interruption, and are electrically connected when charging is unnecessary. Control transistor 23 for discharging the stored voltage of the capacitors 21, 22 of
Is provided.

The control unit 1 is provided with signals a, b, which control the operations of the positive and negative transistors 16, 17, 18, 19 in the first and second energizing circuits 13, 14, respectively. c, d, and a signal e for controlling the operation of the capacitor control transistor 23
And a microcomputer 30 for confirming the operating state of each of the ignition devices 6, 6, 7, 7 via the monitor circuit 24.

The microcomputer 30 is supplied with power from the power supply circuit 3 via a constant voltage circuit 31 of 5V, and the constant voltage circuit 31 monitors ON / OFF of the ignition switch 4. Signal f for resetting and signal g for resetting the microcomputer 30 when the power supply voltage drops.
It is designed to output to.

Further, a signal h from an electrostatic capacitance type deceleration sensor 32 for detecting the deceleration of the vehicle is inputted to the microcomputer 30, and the first and second energizations are carried out. A signal a which conducts each of the transistors 16 to 19 so that the circuits 13 and 14 are energized.
When ~ d is output, the buzzer 35 and the warning lamp 36 are operated via the transistors 33 and 34 by the signals i and j, and the operation of the warning lamp 36 is monitored via the monitor circuit 37. It is supposed to monitor.

In addition to the above configuration, this control unit 1
In, the resistor 40 is connected in parallel with the deceleration switch 15 in the first energization circuit 13, and
First and second voltage dividing resistors 41 and 42 for detecting the voltage are respectively connected to the plus side and the minus side, and these voltage dividing resistors 41 and 42 are connected to the voltage dividing resistors 41 and 42, respectively. The detected voltage is input to the microcomputer 30 as signals x and y.

Then, the microcomputer 30 uses the voltage signals x and y and the signal h from the deceleration sensor 32 to generate the ignition devices 6, 6 in the first and second energizing circuits 13, 14. A signal a for conducting the transistors 16 to 19 on the positive and negative sides of 7 and 7, respectively.
.About.d, and buzzer and warning lamp transistors 33 and 34 respectively output conduction signals i and j.

Here, the capacitor control transistor 2
A cut-off signal is normally output to the signal 3 as the signal e, and the voltage boosted by the voltage boosting circuit 11 holds the first and second capacitors 21 and 22 in a charged state.

Next, the operation of the present embodiment centering on the operation of the microcomputer 30 will be described with reference to the flow chart of FIG.

First, the microcomputer 30 determines in step S1 of the flowchart whether or not the control timing is every 500 μs. If this control timing comes, it is determined in step S2 whether or not the detonating materials for the airbag and the seat belt retractor have already detonated, and if they have not yet detonated, step S2 is performed.
Detonation control of 3 or less is executed.

That is, in step S3, the first data shown in FIG.
The voltage signals x and y from the voltage dividing resistors 41 and 42 on the plus side and the minus side of the deceleration switch 15 in the energizing circuit 13 are read, and these signals x and y are read in step S4.
The difference in voltage indicated by is calculated.

When the calculated value is larger than a predetermined reference value, that is, a large deceleration due to an impact load does not act on the vehicle, and the deceleration switch 15 that opens and closes mechanically is completely open. When the output voltage of the first and second voltage dividing resistors 41, 42 is larger than the reference value by the voltage drop due to the resistor 40 in parallel with the deceleration switch 15, The microcomputer 30 executes step S6, and performs failure diagnosis control of each part of the vehicle according to a separately set program.

On the other hand, in step S5, the first and second voltage dividing resistors 4 on the plus and minus sides of the deceleration switch 15 are placed.
When the difference in the output voltage from 1, 42 is less than the above reference value,
That is, when the deceleration switch 15 detects a large deceleration and closes, the microcomputer 30 determines in step S
7 is executed to determine whether the deceleration indicated by the signal h from the deceleration sensor 32 is larger than a predetermined value. Then, when a deceleration greater than a predetermined value due to the impact load is detected, step S8 is executed, and the ignition devices 6, 6, 7, 7 are operated so as to be energized. That is, the first and second energizing circuits 13,
The energization signals a to d are applied to the transistors 16 to 19 on the plus side and the minus side of each of the ignition devices 6, 6, 7, 7 in FIG.
Is output.

As a result, the ignition devices 6, 6, 7, 7 are activated, the detonator is ignited, the air bag and seat belt retractor is activated, and the occupant is protected from the impact load as described above. It will be.

At this time, the microcomputer 3
When the transistors 33 and 34 are turned on by the signals i and j from 0, the buzzer 35 and the warning lamp 3
6 works.

Then, the microcomputer 30 repeatedly executes the step S9 from the step S9 through the steps S1 and S2, and at the same time, the ignition device 6,
Step S10 is executed at a point of time when 300 ms has passed after the energization of 6, 7, and 7 to perform control for canceling the occupant protection operation by the airbag and the seat belt retractor.

As described above, the ignition devices 6, 6, 7,
The energization control for 7 is performed, but in that case, the deceleration switch 15 that mechanically opens and closes is surely turned on.
The ignition devices 6, 6, 7, and 7 are energized only when the deceleration sensor 32 is in the operating state and the deceleration sensor 32 detects a deceleration larger than a predetermined value. That is, even if the deceleration sensor 32 first detects a deceleration larger than a predetermined value and outputs the signal h, the first and second voltage dividing resistors 41,
Unless the ON operation state of the deceleration switch 15 is confirmed based on the signals x and y from 42, the transistors 16 to 1
Since 9 is not conducted, a large voltage does not act on the deceleration switch 15 and therefore the contacts of the switch 15 may be damaged by the arc discharge of the switch 15 before the deceleration switch 15 is closed. Avoided.

As shown in FIG. 1, in this embodiment, the PNP type transistors 16 and 18 are on the plus side of the ignition devices 6, 6, 7, and 7, and the NPN type transistors 17 and 19 are on the minus side. Are used respectively, the first and second
When the energizing circuits 13 and 14 are energized, a low signal is output to the positive side transistors 16 and 18, and a high signal is output to the negative side transistors 17 and 19, respectively. This is to reduce the possibility of malfunction as compared with the case where the transistors on both sides are activated by the same signal.

Further, in this embodiment, the deceleration switch 15 and the resistors 40 to 42 for detecting the voltage difference between the plus side and the minus side of the deceleration switch 15 are provided only in the first energizing circuit 13 for the air bag ignition devices 6, 6. Although provided, the second energizing circuit 14 for the seat belt retractor may have a similar configuration.

[0034]

As described above, according to the present invention, in a device for controlling occupant protection means such as an air bag or a seat belt retracting device which operates when an impact load is applied, a power source, a contact type deceleration switch, The switch means and the occupant protection means drive section are connected in series, and ON operation state confirmation means for confirming that the deceleration switch is in the ON operation state is provided, and at least this ON operation state confirmation means turns on the deceleration switch. Since the switch means is made conductive on condition that the operating state is confirmed,
Before the deceleration switch is completely closed or when it is open, a large voltage does not act on the switch, which prevents the switch from arcing and damaging the contacts. It Also, the switch
H means consists of two transistors, PNP type and NPN type.
To make these two transistors conductive.
Output low and high signals respectively.
Therefore, the possibility of malfunction can be reduced.

According to the second invention, the ON operation state confirmation means confirms the ON operation state of the deceleration switch,
In addition, the switch means becomes conductive only when the separately provided deceleration sensor detects the deceleration equal to or higher than the predetermined value, so that the malfunction of the occupant protection means can be prevented more reliably.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an occupant protection system showing an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the device.

[Explanation of symbols]

6 Occupant Protection Means Drive Unit (Ignition Device for Airbag) 15 Deceleration Switch 16, 17 Switch Means (Transistor) 30 Control Means (Microcomputer) 32 Deceleration Sensors 40-42 ON Operation State Confirmation Means (Resistor)

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60R 21/32

Claims (2)

(57) [Claims] 1. A power source, a contact-type deceleration switch that is turned on based on the deceleration of the vehicle, a non-contact type switch means, and an occupant protection means, the power source, the deceleration switch, and the switch. Means and a drive part of the occupant protection means are connected in series, and the occupant protection means operates based on the ON operation of the deceleration switch and the conduction of the switch means , wherein the switch means is a PNP type. NPN type
It is composed of two transistors, and is ON to confirm that the deceleration switch is ON.
An operating state confirmation means is provided, and at least the ON state
The switch means is configured on the condition that the operation state check means has confirmed the ON operation state of the deceleration switch.
The two transistors have a low signal that makes them conductive.
An occupant protection device comprising control means for outputting respective high signals . 2. The control means is a switch provided that the ON operation state confirmation means confirms the ON operation state of the deceleration switch and the deceleration sensor provided separately detects deceleration of a predetermined value or more. The occupant protection device according to claim 1, wherein the means is electrically connected.