JPH09164903A - Air-bag control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expect a stable operation, even at the early stage of the turning on of an ignition switch and under the condition of a big temperature change. SOLUTION: At the making time of an electric power supply E, the ignition of the squib DB of an inflator is obstructed by a time limit circuit 70 from the making of the electric power supply E upto the lapse of a prescribed time limit. The output is restricted upto the lapse of the time limit set on the time limit circuit 70, regardless of the output of a self diagnosis circuit 80. After the lapse of the time limit set in the time limit circuit 70, an output terminal B2 . is made to an abnormal output when the output of an oscillation circuit 20 is low in accordance with the self diagnosis circuit 80 of that time. The oscillation circuit 20 is oscillated at a prescribed voltage V, but the distance between a locker panel DR and an inductance L is changed by the collision and the oscillation circuit 20 is escaped from the oscillation state and the output of a differential amplification differential circuit 50 is changed by the drop of its voltage V and an ignition control circuit 90 is turned on and an air-bag is expanded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag control device as an occupant protection device for ensuring passive safety of an occupant, and more particularly to an airbag control device capable of detecting a side collision or a frontal collision. .

[0002]

2. Description of the Related Art In recent years, an airbag control device has been widely used in the automobile industry for the purpose of ensuring passive safety of passengers. In addition to an airbag control device for a frontal collision (head-on collision), recently, An airbag control device for a side collision has also been adopted which protects an occupant from a collision (side collision) on the left and right sides of a vehicle body. Such a side-impact airbag control device is provided with a sensor such as a touch switch on a side door beam inside a door as a collision sensor for detecting a side collision.

As a conventional airbag control device for side impact, there is a technique disclosed in Japanese Utility Model Laid-Open No. 5-563.

The technology disclosed in Japanese Utility Model Publication No. 5-563 is as follows.
A sensor for detecting a side collision is arranged at a position separated from the left and right door panels of the automobile by a predetermined distance, and the sensor is pressed by a body panel which is deformed at the time of a collision so as to conduct electricity. That is, in this technique, the sensor is composed of a fixed contact and a moving contact, and the moving contact is fixed to the door panel so as to approach the fixed contact and make contact with the door when the door is deformed.

[0005]

However, since the conventional air bag control device uses the switch type sensor, the detection is localized, and when the pebbles are hit by a collision, the door is struck, and the garage is put into the garage. There is a possibility that it will work with the door scraping. Further, there is a possibility that the airbag control device may operate even at low speed traveling in which the airbag control device does not need to operate. In order to deal with this kind of problem, it is necessary to dispose a plurality of expensive sensors on the left and right door panels respectively, and the number increases, which leads to an increase in cost.
In addition, the circuit configuration may be complicated.

Further, in the case of a side collision, the crash zone of the vehicle body is smaller than that in a frontal collision, so it is necessary to shorten the collision detection time as much as possible.

[0007] Therefore, the applicant of the present invention, as an airbag device capable of detecting a side collision first, the airbag disposed in the vehicle, the inflator for inflating and deploying the airbag, and the portion displaced at the initial stage of collision of the vehicle body. And an inductance that changes the resonance condition of the resonance circuit that detects a relative change between the portion and the portion that is difficult to displace, and an ignition circuit that determines the output from the resonance circuit and outputs the ignition command signal of the inflator. Invented

However, even if the airbag device has an ignition circuit for judging the output from the resonance circuit and outputting the ignition command signal of the inflator, in order to embody it,
It had to be taken into consideration that the circuit is used in the initial stage of turning on the ignition switch and as a characteristic of the vehicle under the condition of large temperature change.

Therefore, an object of the present invention is to provide an airbag control device which can be expected to have stable operation even at the initial stage of turning on the ignition switch and under the condition that the temperature changes greatly.

[0010]

An air bag control device according to a first aspect of the present invention includes an oscillator circuit in which a resonance condition is changed by an inductance that detects a relative change between a portion of a vehicle body that is displaced in the initial stage of a collision and a portion that is difficult to be displaced. A detection circuit for detecting and smoothing the oscillation state of the oscillation circuit; an output circuit for outputting a squib by outputting when the magnitude of the differential value of the output of the detection circuit is not less than a predetermined value; and the oscillation circuit. Self-diagnosis circuit that monitors whether the oscillation state is stable,
A time limit circuit for restraining the output of the output circuit and the self-diagnosis circuit until the time when the oscillator circuit is in a stable oscillation state, and restrains the output of the output circuit until the oscillator circuit is in a stable oscillation state. The output of the output circuit and the output of the self-diagnosis circuit at the initial stage of power-on are restrained by the time limit circuit.

The airbag control device according to claim 2 is
An oscillation circuit whose resonance condition changes due to an inductance that detects a relative change between a portion that is displaced in the initial stage of a vehicle body collision and a portion that is difficult to displace, and a detection circuit that detects and smoothes to detect the oscillation state of the oscillation circuit. An output for calculating the difference between the output of the detection circuit and the output of the temperature compensation circuit and comparing the magnitude of the differential value with the temperature compensation circuit in which the connection conditions of the transistors of the oscillation circuit and the detection circuit are matched. A circuit, a self-diagnosis circuit for monitoring the output of the output circuit for a stable oscillation state of the oscillation circuit, and a constraint of the output of the output circuit until the time when the oscillation circuit becomes a stable oscillation state And a time compensating circuit, the output of the temperature compensating circuit and the output of the oscillating circuit and the detecting circuit, which are obtained by matching the connection conditions of the transistors of the oscillating circuit and the detecting circuit. Calculates the difference, cancel the temperature dependency by the output circuit for comparing the magnitude of the differential value, also,
The output of the output circuit is restricted by the time limit circuit that restricts the output of the output circuit until the time when the oscillation circuit is in a stable oscillation state, and the output of the output circuit is restricted at the initial stage of power-on. Is for restraining the output of the self-diagnosis circuit for monitoring whether it is in a stable state.

The airbag control device according to claim 3 is
The connection between the base and emitter of the transistor forming the oscillation circuit and the detection circuit and the connection between the base and emitter of the transistor of the temperature compensation circuit are matched, and the differential between the two is taken by a differential amplifier circuit. It cancels the temperature dependence of the oscillator circuit and eliminates the temperature-dependent signal after the output of the differential amplifier circuit.

[0013]

Embodiments of the present invention will be described below.

FIG. 1 is an explanatory view showing a mounting position of an airbag control device according to an embodiment of the present invention to a vehicle body. FIG. 2 is a characteristic diagram showing an output signal at the time of a side collision of the eddy current displacement sensor of the airbag control device according to the embodiment of the present invention, and shows an output signal at the time of a right side collision. FIG. 3 is a perspective view showing a state in which the airbag control device according to the embodiment of the present invention is attached to a seat (driver's seat).

The airbag control device according to the present embodiment has a side airbag storage portion 15 in which airbags are respectively stored on the left and right sides of the interior of an automobile, for example, on the door sides of the driver's seat 3 and the passenger seat 5 of the vehicle body 1. (See FIG. 3 showing an example of the arrangement in the driver's seat 3), and the side airbag storage portion 15 is provided.
The left and right inflators (not shown) built in the inflator deploy the inflatable side airbags. Particularly, in the side airbag storage portion 15, its casing is directly screwed to the seat frame 7 of the driver's seat 3.
Installed in. The output of the side airbag control device 10 is input to a main control device 17 that houses a power source E and a microcomputer or the like that is set as necessary, and the side airbag storage portion 15 stores the squib (D) of the inflator on the driver's seat 3 side. Seat squib) Controls the DS signal.

The airbag control device of this embodiment uses the sensor shown in FIG. 4 as a sensor for detecting the impact at the time of collision. That is, the sensor is the door 16
The eddy current shown in the oscillation circuit 20 of the side airbag control device 10 of FIG. 4 that detects a change in eddy current loss generated by the rocker panel DR made of an iron plate that is built in the inside and faces the inductance L as a change in distance. The displacement sensors 2 and 4 are used. The eddy current displacement sensors 2 and 4 are
It is arranged inside the doors of the driver's seat 3 and the passenger seat 5.

In this embodiment, as shown in FIG. 1, the eddy current displacement sensors 2 and 4 are arranged on the left and right of the vehicle body 1. As a result, the eddy current displacement sensors 2 and 4 can detect the displacement of the vehicle body in the left-right direction. For example, the eddy current displacement sensor 2 generates a positive voltage as shown in FIG. 2 when a displacement in the left direction occurs during a right-side collision.
Further, when a displacement occurs in the right direction at the time of a left-side collision, the eddy current displacement sensor 4 produces an output similar to that of FIG. 2 and a negative polarity voltage equivalent to the positive polarity voltage. In addition,
The polarity of the output signal generated by the eddy current displacement sensors 2 and 4 may be opposite to that shown in FIG.

Next, the circuit configuration of the side airbag control device of this embodiment will be described. FIG. 4 is a control circuit diagram for controlling the airbag control device according to the embodiment of the present invention.

The side airbag storage portion 15 of this embodiment
Is an ignition control circuit 90 for controlling the ignition of the squib DS of the inflator on the right side, that is, the driver's seat 3 side, and an ignition control circuit 90 for controlling the ignition of the squib of the inflator on the left side, that is, the passenger seat 5 side (P seat squib) shown in FIG. An ignition control circuit 90 is provided. That is, the ignition control circuit 90 includes a switching element such as a transistor T71 and a squib D driven by the switching element.
It is composed of S. The squib DS of the inflator on the driver's seat 3 side is connected to the transistor T71, and when the transistor T71 is turned on, the squib DS is ignited.

Since the basic circuit configuration of the side airbag control device of this embodiment is the same, only the ignition control circuit on the driver's seat 3 side will be described here.

In the figure, a power source E indicates a constant voltage power source and a battery, and a large-capacity capacitor C0 is connected in parallel in consideration of fluctuation of a predetermined power source and noise.

As the self-excited oscillating circuit of this embodiment, an oscillating circuit 20 comprising a Colpitts oscillating circuit has an oscillating frequency f determined by an inductance L, a capacitor C1 and a capacitor C2, and this oscillating frequency f is f = √ { 1 / L (C1.C2 / C1 + C2)} / 2.pi., And self-oscillation occurs at this oscillation frequency f. The value of the inductance L is determined by the distance from the rocker panel DR made of an iron plate facing the inductance L. The resistors R3 and R2 and the capacitor C4 are connected to the transistor T1.
To obtain a base current of R1, and the resistor R1 is an output resistor. The capacitor C3 is for removing noise. The inductance L is contained in a casing which is not a magnetic body. In particular, with the inductance L and the rocker panel DR made of an iron plate facing the inductance L,
In this embodiment, the eddy current displacement sensors 2 and 4 are configured.

The detection circuit 30 uses the transistor T11 as a diode, and a charging / discharging circuit including a capacitor C11 and a resistor R11 and a filter including a resistor R12, a resistor R13, a capacitor C13, a capacitor C12 and an output resistor R14, and an operational amplifier OP1. That is, a smoothing circuit is configured, and a low-pass filter that smoothes the detection output of the transistor T11 that detects the oscillation state of the oscillation circuit 20 is configured.

The temperature compensating circuit 40 includes a resistor R3 for obtaining a base current of the transistor T1, a resistor R2 and a capacitor C.
From the connection point of 4, the base current of the transistor T21 connected in series with the resistor R21 and the resistor R22 is obtained, and from the resistor R22 which functions as the output resistor of the transistor T21,
Obtain the base current of the transistor T22,
The input of the operational amplifier OP2 for impedance conversion is obtained from the resistor R23 which functions as the output resistor of 22. The transistor T21 and the transistor T22 that perform amplification in two stages are
The element and the current are set so that the transistor T1 of the oscillation circuit 20 and the transistor T11 of the detection circuit 30 have the same temperature characteristics.

The differential amplification differential circuit 50 subtracts the output of the detection circuit 30 and the output of the temperature compensation circuit 40 and the differential amplifier OP3 including the input resistance R31, the input resistance R32, the feedback resistance R33, and the feedback resistance R34. Is differentiated by a differentiation circuit composed of a capacitor C31 and a resistor R35,
Amplify with resistor R36, resistor R37 and operational amplifier OP4,
It is input to one of the comparators OP5. To the other side of the comparator OP5, the connection point potential of the resistors R38, R39 and the capacitor C32 is inputted. Therefore, when the output of the operational amplifier OP4 is equal to or lower than the threshold voltage Th1 by the threshold voltage Th1 determined by the resistors R38 and R39, the comparator OP5 outputs “L”.
When the output of the operational amplifier OP4 exceeds the threshold voltage Th1, "H" is output.

The output of the comparator OP5 is input to the integral comparison circuit 60. The integration comparison circuit 60 is input to a charging / discharging circuit including a diode D41, a resistor R41 and a capacitor C41 and an integrating circuit including a resistor R42, a resistor R43 and a capacitor C42, and a connection potential between the resistor R42, the resistor R43 and the capacitor C42 is It is input to the base of the transistor T41. The transistor T41 is connected in series with the pull-up resistor R44, and the potential at the connection point is connected via the inverter IN to the base of the transistor T71 which is connected in series with the squib DS of the inflator on the driver seat 3 side. Therefore, the resistors R42 and R43 and the capacitor C
When the connection potential with 42 becomes high, the base current of the transistor T41 flows, the transistor T41 is turned on, the potential at the connection point with the pull-up resistor R44 changes from “H” to “L”, and the driver seat is connected via the inverter IN. The base potential of the transistor T71 connected in series with the squib DS of the inflator on the third side changes from "L" to "H", and
The squib DS is ignited when 71 is turned on. That is, the output of the side air bag control device 10 is input to the main control device 17 shown in FIG. 3 which houses the power source E and the microcomputer set as necessary, and the ignition built in the side air bag housing portion 15 is input. The squib DS of the inflator on the driver's seat 3 side is ignited by the control circuit 90.

Incidentally, the diode D41 of the integration / comparison circuit 60.
The charging / discharging circuit consisting of the resistor R41 and the capacitor C41 is
In order to improve the rising responsiveness, the charging speed for charging with a positive potential is fast, and when discharging, the discharge is sequentially performed by the time constant of the resistor R41.

The time limit circuit 70 has a threshold voltage Th2 determined by resistors R62 and R63, a diode D61 and a resistor R61.
And a capacitor C61, and a comparator OP7. When the power supply E is turned on and the voltage of the charging circuit composed of the resistor R61 and the capacitor C61 increases with a predetermined time constant and exceeds the threshold voltage Th2 determined by the resistors R62 and R63, the output of the comparator OP7 becomes " It changes from "L" to "H". That is, when the output of the comparator OP7 is "L", the diode D42 is forward biased, and the base voltage of the transistor T41 is forcibly pulled to "L" for a predetermined time period, and the transistor T42 is in the meantime.
Prevent 41 from turning on.

The self-diagnosis circuit 80 compares the detection output of the detection circuit 30 and the potential of the connection point of the resistors R51, R52 and the capacitor C51, that is, the threshold voltage Th3 with the comparator OP6.
And the output of the comparator OP6 is input to the integrating circuit composed of the resistor R53 and the capacitor C51. A resistor R54 is connected to the capacitor C51, and the connection potential of the resistor R53 and the capacitor C52 is connected to the base of a transistor T51 connected in series with the resistor R55. The connection potential of the resistor R53 and the capacitor C52 is connected to the output of the comparator OP7 by the diode D51. Then, it is connected to the base of a transistor T51 connected in series with a resistor R55. The connection potential between the resistor R55 and the transistor T51 is connected to the output terminal Bz via the resistor 56. The output terminal Bz is used when an abnormality is reported.

Therefore, the comparator OP6 compares the threshold voltage Th3 determined by turning on the power supply E with the detection output of the detection circuit 30, and when the detection output of the detection circuit 30 is high, that is, the output of the oscillation circuit 20 is strong. At this time, the output of the comparator OP6 becomes "L", and the output terminal Bz becomes "H" regardless of whether the output of the time-limit circuit 70 is "L" or "H", which is a normal output.

Further, the comparator OP6 compares the threshold voltage Th3 determined by turning on the power supply E with the detection output of the detection circuit 30, and when the detection output of the detection circuit 30 is low, that is, the output of the oscillation circuit 20 is weak. At this time, the output of the comparator OP6 becomes "H", but the output terminal Bz becomes "H" while the output of the timing circuit 70 is "L". But,
When the output of the time limit circuit 70 shifts to "H", the transistor T51 is turned on and the output terminal Bz becomes "L" indicating an abnormality of the oscillation circuit 20.

Next, the operation of the side airbag control device of this embodiment constructed as described above will be described.

As described above, when the distance between the inductance L built in the door 16 of the present embodiment and the rocker panel DR is within a predetermined distance range, the value of the inductance L and the capacitor C1 and Capacitor C2
At the oscillation frequency f determined by, the oscillation circuit 20 including the Colpitts oscillation circuit is in the oscillation state or the frequency state near the oscillation. At this time, the current of the transistor T1 of the oscillating circuit 20 is a maximum current or a current close thereto, and a predetermined voltage V is generated in the resistor R1 due to a voltage drop, and the magnitude of the voltage V is maximum or close to it. It is in the value. The maximum value of the voltage V or a value close to it is the rocker panel DR and the inductance L.
It is determined by the mounting accuracy between and.

That is, in a normal state, when the distance between the rocker panel DR of the present embodiment and the inductance L is within a predetermined distance range, the oscillation determined by the value of the inductance L and the capacitors C1 and C2 at that time. The frequency f is uniquely determined, and a predetermined voltage V is generated in the resistor R1 of the oscillation circuit 20 due to the voltage drop. However, when the rocker panel DR bends inward due to a collision or the like, and the distance between the rocker panel DR and the inductance L changes abruptly, the value of the inductance L causes the oscillation circuit 20 to exit the oscillation state or resonate. Move away from the point.
At this time, in the current of the transistor T1, the maximum current or a current close to the maximum current sharply decreases, and the voltage V of the resistor R1 decreases.

This output voltage V is detected by the transistor T11 of the detection circuit 30, and it is charged in the capacitor C11. The resistor R11 is used to discharge the electric charge stored in the capacitor C11. The voltage V charged in the capacitor C11 is smoothed by the integrating circuit including the capacitor C12, the resistor R13 and the operational amplifier OP1.

On the other hand, the temperature compensating circuit 40 makes the base current of the transistor T21 from the connection point of the resistor R3, the resistor R2 and the capacitor C4 which obtain the base current of the transistor T1 in order to match the current of the transistor T21 with the current of the transistor T1. Then, the base-emitter connection of the transistor T21 and the transistor T22 for performing amplification in two stages is performed under the same conditions as the base-emitter of the amplification transistor T1 and the detection transistor T11.

At this time, there is a relationship shown in FIG. 2 between the output voltage V1 of the output of the oscillation circuit 20 which has passed through the detection circuit 30 and the output voltage V2 of the temperature compensation circuit 40.

FIG. 5 is an output characteristic diagram of the detection circuit and the temperature compensation circuit of the airbag control apparatus of one embodiment of the present invention. The inductance L of the oscillation circuit 20 is oscillated without applying an external condition, It is a temperature-voltage characteristic when temperature is changed. FIG. 6 is an output characteristic diagram of the differential amplifier OP3 of the differential amplification differentiating circuit 50 of the airbag control device according to the embodiment of the present invention.

As shown in FIG. 5, the output voltage V1 which varies depending on the base and emitter of the amplifying transistor T1 and the detecting transistor T11, and the output voltage V1 between the base and emitter of the transistor T21 and the transistor T22 which perform amplification in two stages. It can be seen that the output voltage V2, which varies depending on, has the same proportional multiplier.

Therefore, the output voltage V1 which changes depending on the base-emitter of the amplifying transistor T1 and the detecting transistor T11, and the output voltage which changes depending on the base-emitter of the transistor T21 and the transistor T22 which perform two-stage amplification. The output voltage V3 of the differential amplifier OP3 of the differential amplification differentiating circuit 50, to which V2 is input, is 2 when the output voltage V1 which varies depending on the base-emitter of the amplifying transistor T1 and the detecting transistor T11.
Transistor T21 and transistor T22 that perform amplification in stages
It can be seen that the output voltage V2 that varies depending on the base-emitter of the above is canceled and the output does not depend on the temperature, as shown in FIG. Of course, the output voltage V3 in FIG. 6 is an output proportional to the voltage V of the oscillation circuit 20.

The output voltage V3 proportional to the voltage V of the oscillating circuit 20 is differentiated by a differentiating circuit consisting of a capacitor C31 and a pull-down resistor R35, which is amplified by a resistor R36, a resistor R37 and an operational amplifier OP4, and a threshold voltage by a comparator OP5. Compared with Th1.

In the normal state, the oscillation circuit 20 has a predetermined voltage V
However, when the rocker panel DR made of an iron plate facing the inductance L approaches a distance due to a collision, a change in the distance appears as a change in the eddy current loss, and the voltage V decreases. The decrease in the voltage V of the oscillation circuit 20 is amplified by the operational amplifier OP4. The decrease in the output of the operational amplifier OP4 inverts the output of the comparator OP5 from "L" to "H".

The change of the output of the comparator OP5 from "L" to "H" causes the capacitor C41 to be rapidly charged through the diode D41, and as a result, the voltage of the capacitor C42 is increased. The time limit generated at this time has a function of lengthening the output pulse width in order to increase the reliability of the output.
The base potential of the transistor T41 is raised, and the transistor T41 is turned on. At this time, the intrusion of noise does not increase the base potential of the transistor T41.
When the transistor T41 is turned on, the output of the side airbag control device 10 is input to the main control device 17 shown in FIG. 3, and the output of the inverter IN is "L" until then, the output is "H", and the side air is controlled. The squib DS of the inflator on the driver's seat 3 side is ignited by the ignition control circuit 90 built in the bag storage portion 15 to inflate the side airbag.

However, when the power source E is turned on, the oscillation circuit 2
0 does not oscillate, and even if it oscillates, the resistance R1
The predetermined voltage V in the steady state is not generated until a predetermined time elapses. At this time, the oscillation circuit 20 has a voltage equal to or lower than a predetermined voltage V, and when the rocker panel DR made of an iron plate facing the inductance L approaches a distance due to a collision, the change in the distance appears as a change in the eddy current loss, and the voltage changes. Since V is the same as when it has dropped, the comparator OP
The output of 5 is "H". Since "H" of the output of the comparator OP5 raises the voltage of the capacitor C42, the base potential of the transistor T41 is high and the transistor T41 is on. When the transistor T41 is turned on, the output of the inverter IN becomes "H". That is,
The squib DS of the inflator on the driver's seat 3 side is ignited to inflate the airbag.

Then, the power source E is turned on by the time limit circuit 70, and the charging voltage of the capacitor C61 of the charging circuit consisting of the resistor R61 and the capacitor C61 increases with a predetermined time constant,
Until the threshold voltage Th2 determined by the resistors R62 and R63 is exceeded, the output of the comparator OP7 is set to "L", the diode D42 is set to forward bias, and the base voltage of the transistor T41 is forcibly pulled to "L". Meanwhile, it prevents the transistor T41 from turning on. That is, depending on the time limit set in the time limit circuit 70, the transistor T
41 is kept off and the output of the inverter IN is "L".
To prevent ignition of the squib DS of the inflator on the driver's seat 3 side.

On the other hand, the self-diagnosis circuit 80 compares the threshold voltage Th3 determined by turning on the power supply E with the detection output of the detection circuit 30 in the steady state of the oscillation circuit 20 by the comparator OP6, and the detection of the detection circuit 30 is performed. When the output is low, that is, when the output of the oscillating circuit 20 is low, the output of the comparator OP6 is "H", but since the output of the time limit circuit 70 is "L", the diode D51 is forward biased and the output. The terminal Bz becomes "H", which is a normal output. Further, even if the output of the oscillation circuit 20 becomes high and the output of the comparator OP6 becomes “L”, the time limit circuit 7
When the output of 0 is "L", the diode D51 is forward biased and the transistor T51 is not turned on. That is, the transistor T51 remains in the off state until the time set in the time limit circuit 70 elapses regardless of the output "H" or "L" of the comparator OP6 of the self-diagnosis circuit 80, and the output terminal Bz is "H". It is an output at the time of normal.

When the time limit set in the time limit circuit 70 has elapsed, the output of the comparator OP7 of the time limit circuit 70 is "H".
Then, the diode D51 is reverse biased, and according to the self-diagnosis circuit 80 at that time, when the output of the oscillation circuit 20 is high, the output of the comparator OP6 becomes “L”,
The output terminal Bz is "H" when the transistor T51 is off.
Is the normal output. When the output of the oscillator circuit 20 is low, the output of the comparator OP6 becomes "H", the transistor T51 is turned on, and the output terminal Bz is "L".
It will be output at the time of abnormality. When the signal of the output terminal Bz is "L", the output of the abnormality is lit or blinking red, or the circuit of the side airbag control device 10 is abnormal for a predetermined time after the ignition switch is turned on. Used to inform.

Further, in the present embodiment, the driver's seat 3 has been described, but the driver's seat 3 can be similarly arranged on the passenger seat 5 side or the rear seat side.

As described above, the airbag control device as the side airbag control device 10 of the present embodiment includes an airbag (not shown) provided in the vehicle, a squib DS of an inflator for inflating and deploying the airbag. The inductance L that determines the oscillation condition of the oscillation circuit 20 disposed at the relative position between the portion that is displaced in the initial stage of the collision of the vehicle body 1 and the portion that is difficult to be displaced, and the detection and smoothing are performed to detect the oscillation state of the oscillation circuit 20. A temperature compensating circuit 40 having a detection circuit 30 and transistors T21 and T22 in which the connection conditions of the oscillation circuit 20 and the transistors T1 and T11 of the detection circuit 30 are matched.
And a difference between the output of the detection circuit 30 and the output of the temperature compensation circuit 40, and outputs it when the magnitude of the differential value is greater than or equal to a predetermined value to fire the squib DS.
And an output circuit including an integration / comparison circuit 60, and an oscillation circuit 2
Self-diagnosis circuit 8 that monitors whether 0 is in a stable oscillation state
0, and an output circuit including the differential amplification differentiating circuit 50 and the integral comparison circuit 60 and a time limit circuit 70 for restraining the output of the self-diagnosis circuit 60 until the time when the oscillation circuit 20 becomes a stable oscillation state. This can be an embodiment corresponding to the claims.

Normally, the oscillating circuit 20 oscillates at a predetermined voltage V, but when the rocker panel DR bends inward due to a collision or the like and the distance between the inner panel DR and the inductance L changes abruptly, Depending on the value of the inductance L of the oscillation circuit 20, the oscillation circuit 20 exits the oscillation state and the voltage V drops. The decrease in the voltage V of the oscillation circuit 20 inverts the output of the differential amplification differentiating circuit 50 from "L" to "H". The change of the output of the differential amplification differentiating circuit 50 from “L” to “H” changes the output of the integral comparing circuit 60 from “H” to “L”,
The transistor T71 of the ignition control circuit 90 is turned on. That is, the squib DS of the inflator on the driver's seat 3 side is ignited by the ignition control circuit 90 which is input to the main controller 17 shown in FIG.

However, when the power source E is turned on, the oscillation circuit 2
0 does not oscillate, and even if it oscillates, the resistance R1
Since the predetermined voltage V in the steady state is not generated until the predetermined time elapses, the squib DS of the inflator on the driver's seat 3 side is ignited to inflate the airbag. Therefore, the time limit circuit 70 blocks ignition of the squib DS of the inflator until a predetermined time period elapses after the power source E is turned on.

Further, the comparator O of the self-diagnosis circuit 80
Regardless of the "H" or "L" of the output of P6, the transistor T51 is used until the time set in the time circuit 70 elapses.
Remains off, and the output terminal Bz is used as a normal output. After the time limit set in the time limit circuit 70 has elapsed, when the output of the oscillation circuit 20 is high according to the self-diagnosis circuit 80 at that time, the output of the comparator OP6 becomes "L",
The output terminal Bz is "H" when the transistor T51 is off.
Is the normal output. When the output of the oscillator circuit 20 is low, the output of the comparator OP6 becomes "H", the transistor T51 is turned on, and the output terminal Bz is "L".
It will be output at the time of abnormality.

According to this embodiment, the maximum value of the voltage V or a value close to it is determined by the mounting accuracy between the rocker panel DR and the eddy current displacement sensor 4, but the resonance By setting the condition Q, the diameter of the inductance L, the number of windings, and the current, it is possible to reduce the error in the distance between the rocker panel DR and the inductance L, that is, the mounting error. However, even if the sensitivity is increased so as to increase the Q of these resonance conditions, since the speed at which the rocker panel DR bends inward is detected, it is not affected by the mounting error at all. Further, when the self-excited oscillation is maintained in the normal state and the self-excited oscillation is no longer maintained, it is determined that the rocker panel DR bends inward, and the collision speed is determined based on the bending speed. It doesn't work when the sides touch. Further, since the oscillation is always maintained by itself and the change of the opposing rocker panel DR is detected, it is possible to constantly monitor a predetermined wide range and highly reliable detection is possible. Further, since the self-excited oscillation circuit is used as the oscillation circuit 20, there is no need to add a circuit element for forced oscillation from the outside, and the circuit can be simplified.

Further, the temperature compensating circuit 40 makes the base current of the transistor T21 from the connection point of the resistor R3, the resistor R2 and the capacitor C4 for obtaining the base current of the transistor T1 so that the current of the transistor T21 matches the current of the transistor T1. Then, the base-emitter connection of the transistor T21 and the transistor T22 for performing amplification in two stages is performed under the same conditions as the base-emitter of the amplification transistor T1 and the detection transistor T11. Therefore, the output voltage V1 that changes depending on the base-emitter of the amplifying transistor T1 and the detecting transistor T11, and the transistor T that performs amplification in two stages
The output voltage V2, which varies depending on the base-emitter of the transistor 21 and the transistor T22, has the same characteristics, and the output voltage V3 of the differential amplifier OP4 of the differential amplifier differentiating circuit 50, which receives the output voltage V2, is the same as that of the transistor T1 for amplification and the detection. The output voltage V1 which varies depending on the base-emitter of the transistor T11 for use in the output is canceled by the output voltage V2 which varies depending on the base-emitter of the transistor T21 and the transistor T22 which performs amplification in two stages, resulting in an output independent of temperature. The output is proportional to the voltage V of the oscillation circuit 20.

In the present embodiment, the temperature compensation circuit 40 is used to perform temperature compensation. As the temperature compensation circuit for implementing the present invention, the oscillation circuit 20 is a circuit using diode PN coupling. It may be configured and compensated thereby, or a thermistor may be used.

In the differential amplification differentiating circuit 50, the time when the output of the oscillating circuit 20 suddenly changes is detected by the differentiating circuit composed of the capacitor C31 and the resistor R35, and the collision is detected by the magnitude of the differential value. There is. That is, according to the present embodiment, the influence of the temperature dependence of the oscillation circuit 20 is small. Therefore, the circuit configuration of FIG. 7 can be adopted.

FIG. 7 is a control circuit diagram for controlling an airbag control device according to another embodiment of the present invention. In the figure,
The same reference numerals and symbols as those of the above-described embodiment indicate the same or corresponding components as those of the above-described embodiment, and therefore, duplicate description will be omitted and only different points will be described.

In this embodiment, FIG. 7 shows the temperature compensating circuit 4.
0 and the differential amplifier OP4 of the differential amplification differentiating circuit 50 is omitted, and the differential comparison in which the output of the operational amplifier OP1 of the detection circuit 30 is input to the comparator OP5 via the differentiating circuit composed of the resistor R300, the capacitor C31 and the resistor R35. The circuit 100 is used.

Therefore, according to the present embodiment, the temperature compensating circuit 40 and the differential amplifying / differentiating circuit 50 can be omitted and the device can be made inexpensive. In particular, also in the present embodiment, the other configurations and operational effects are the same except that the temperature compensation function in the above embodiment is not provided.

That is, the airbag control device as the side airbag control device 10 of the present embodiment includes an airbag (not shown) provided in the vehicle, a squib DS of an inflator for inflating and deploying the airbag, and the vehicle body 1 Of the oscillation circuit 20 disposed at a relative position between the portion that is displaced at the initial stage of collision and the portion that is difficult to displace, and a detection circuit that detects and smoothes the oscillation state of the oscillation circuit 20 to detect the oscillation state. Whether the output circuit 30 and the output circuit including the integral comparison circuit 60 or the like that outputs when the magnitude of the differential value of the output of the detection circuit 30 is equal to or larger than a predetermined value and fires the squib DS, and the oscillation circuit 20 are in a stable oscillation state. Output of the self-diagnosis circuit 60 to be monitored and the output circuit including the integration comparison circuit 60 and the like until the oscillation circuit 20 reaches a stable oscillation state and the self-diagnosis circuit 60. It is intended to and a timing circuit 70 for restraining can be an example corresponding to this claim.

By the way, in each of the above embodiments, a Colpitts circuit is adopted as the oscillation circuit 20 in which the resonance condition is changed by the inductance L which detects the relative change between the portion of the vehicle body 1 which is displaced at the initial stage of the collision and the portion which is difficult to be displaced. However, when the present invention is implemented, the present invention is not limited to the Colpitts oscillation circuit, and an oscillation circuit that obtains a resonance condition by the inductance L of the Hartley oscillation circuit or the like, or a resonance circuit by separately excited, that is, separately excited oscillation. Any circuit will do.

Further, in the oscillation circuit 20 of each of the above embodiments, the detection circuit 30 for detecting and smoothing to detect the oscillation state detects and smoothes the output of the oscillation circuit 20 by the transistor T11. In the case of implementing the present invention, it is sufficient that the resonance state is detected and can be expressed as a change in DC voltage.

In the temperature compensating circuit 40 of the above embodiment, the connection conditions of the transistors T21 and T22 of the oscillation circuit 20 and the detection circuit 30 are made to match, but when the present invention is carried out. The temperature compensating circuit 40 can be omitted as shown in FIG. Also,
It can be replaced with another circuit element.

Further, the output circuit of the above embodiment calculates the difference between the output of the detection circuit 30 and the output of the temperature compensation circuit 40, and outputs it when the magnitude of the differential value is greater than or equal to a predetermined value to obtain the squib DS. It is composed of a differential amplification differentiating circuit 50 and an integration comparing circuit 60 for firing, but in the case of implementing the present invention, when the magnitude of the differential value of the output of the detection circuit 30 is not less than a predetermined value, it is output, Any circuit may be used as long as it is a circuit for making a comparison judgment to fire the squib DS.

Furthermore, the oscillator circuit 20 of each of the above-mentioned embodiments.
Self-diagnosis circuit 80 for monitoring whether the oscillator is in a stable oscillation state
Determines whether a predetermined output voltage is generated in the oscillating circuit 20, but when the present invention is carried out, it is possible to perform self-diagnosis by judging whether it is at a predetermined oscillation frequency, that is, Q. .

In addition, the time limit circuit 70 of each of the above embodiments.
Limits the output of the output circuit and the self-diagnosis circuit 80 until the oscillation circuit 20 reaches a stable oscillation state. However, in the case of implementing the present invention, at least the oscillation circuit 20 has a stable oscillation state. If the output circuit and the output of the self-diagnosis circuit 80 are restricted until the time becomes,
As a matter of course, it is possible to set a variable time limit until the vehicle reaches a predetermined speed. Alternatively, the time period can be set based on the stable circuit condition.

According to each of the above-mentioned embodiments, the maximum value of the voltage V or a value close to it is the rocker panel DR.
Is determined by the mounting accuracy between the rear eddy current displacement sensor 4A and the front eddy current displacement sensor 4B. It depends on the setting of the resonance condition Q, the diameter of the inductance L, the number of windings, and the current. The error in the distance between the rocker panel DR and the inductance L, that is, the mounting error can be reduced. Further, since the collision is determined based on the value when the rocker panel DR bends inward, even if the rocker panel DR is partially deformed to the vehicle interior side and the vehicle exterior side, the entire change of the opposing rocker panel DR is detected. Therefore, it is possible to constantly monitor a predetermined wide range, and it is possible to perform highly reliable detection. For example, even when skidding on a frozen road surface, it can be dealt with. Further, the vehicle body 1 that has already been deformed can operate.

Although the side air bag control device 10 has been described in the above embodiment, the present invention is not limited to the side air bag control device 10 and is generally used for an air bag control device. it can.
In particular, it can be applied to large vehicles with few crash zones such as trucks and buses.

In the above embodiment, the side air bag control device 10 and the ignition control circuit 90 are separately incorporated. However, in the case of implementing the present invention, the inside of the side air bag control device 10 is described. Ignition control circuit 9
Alternatively, the ignition control circuit 90 may be incorporated in the interior space of the door or the interior space of the seat. Further, although the output of the side airbag control device 10 is directly used for the ignition control circuit 90, in the case of implementing the present invention, the output of the side airbag control device 10 is input to a microcomputer, and the microcomputer Can also be used to determine whether the incoming signal is a side airbag control signal to improve the reliability of its operation.

Although the Colpitts oscillation circuit is used as the oscillation circuit 20 in the above embodiment, when the present invention is implemented, a Hartley oscillation circuit, a Clapp oscillation circuit, a transistor coupling type oscillation circuit or the like can be used. Is. In particular, the Colpitts oscillator circuit has one inductance L, but the Hartley oscillator circuit having two inductances enables a wider range of sensing.

[0071]

As described above, the airbag control device according to the first aspect of the invention is an oscillator circuit in which the resonance condition changes due to the inductance that detects the relative change between the portion that is displaced in the initial stage of a collision of the vehicle body and the portion that is difficult to displace. Detection and smoothing are performed to detect the oscillating state, and when the magnitude of the differential value of the output is greater than or equal to a predetermined value, the squib is ignited by outputting. The self-diagnosis circuit monitors whether the oscillation circuit is in a stable oscillation state,
The time limit circuit restrains the output for firing the squib until the oscillation circuit is in a stable oscillation state.

Therefore, when the oscillation circuit is oscillating at a predetermined voltage, if the inductance changes suddenly due to a collision or the like, the oscillation state is released, the squib of the inflator is ignited, and the airbag is inflated. The sensor and the control circuit can be integrally formed or separated from each other, and the resonance circuit is a self-excited or separately-excited oscillation circuit, that is, a frequency generation circuit. , A resonance circuit such as a filter can be used, and the degree of freedom in circuit design is increased.
When the power is turned on, the oscillating circuit is not oscillating, and even if it is oscillating, the predetermined output voltage has not been reached, so ignition of the squib is blocked. Further, regardless of the output of the self-diagnosis circuit, the output terminal is set to the normal output until the time set in the time limit circuit elapses. Therefore, stable operation can be expected even in the initial stage of turning on the ignition switch.

The airbag control device according to claim 2 is
An oscillation circuit whose resonance condition changes due to an inductance that detects a relative change between a portion that is displaced in the initial stage of a vehicle body collision and a portion that is difficult to displace, and a detection circuit that detects and smoothes to detect the oscillation state of the oscillation circuit. An output for calculating the difference between the output of the detection circuit and the output of the temperature compensation circuit and comparing the magnitude of the differential value with the temperature compensation circuit in which the connection conditions of the transistors of the oscillation circuit and the detection circuit are matched. A circuit, a self-diagnosis circuit for monitoring the output of the output circuit for a stable oscillation state of the oscillation circuit, and a constraint of the output of the output circuit until the time when the oscillation circuit becomes a stable oscillation state And a time compensating circuit, the output of the temperature compensating circuit and the output of the oscillating circuit and the detecting circuit, which are obtained by matching the connection conditions of the transistors of the oscillating circuit and the detecting circuit. Calculates the difference, cancel the temperature dependency by the output circuit for comparing the magnitude of the differential value, also,
The output of the output circuit and the output of the self-diagnosis circuit at the initial stage of power-on rise are restricted by a time-limit circuit that restricts the output of the output circuit until the oscillation circuit reaches a stable oscillation state. Is.

Therefore, when the oscillation circuit is oscillating at a predetermined voltage, if the inductance changes suddenly due to a collision or the like, the oscillation state is released, the squib of the inflator is ignited, and the airbag is inflated. The sensor and the control circuit can be integrally formed or can be separated from each other, and the resonance circuit is a self-excited or separately-excited oscillation circuit, that is, a frequency generation circuit. , A resonance circuit such as a filter can be used, and the degree of freedom in circuit design is increased.
When the power is turned on, the oscillating circuit is not oscillating, and even if it is oscillating, the predetermined output voltage has not been reached, so ignition of the squib is blocked. Further, regardless of the output of the self-diagnosis circuit, the output terminal is set to the normal output until the time set in the time limit circuit elapses. Then, the temperature compensating circuit connects the base and emitter of the transistor for performing amplification in two stages under the same conditions as the base and emitter of the transistor for amplification and the transistor for detection, and the transistor for amplification and the detector for detection are connected. The temperature characteristics between the base and emitter of the transistor and the temperature characteristics that change depending on the base and emitter of the transistor that performs amplification in two stages are matched and cancelled, and the output does not depend on the temperature. Therefore, stable operation can be expected even in the initial stage of turning on the ignition switch and under the condition of large temperature change.

The airbag control device according to claim 3 is
The connection between the base and emitter of the transistor forming the oscillation circuit and the detection circuit and the connection between the base and emitter of the transistor of the temperature compensation circuit are matched, and the differential between the two is taken by a differential amplifier circuit. Since the temperature dependence of the oscillation circuit is canceled and the signal dependent on the temperature is eliminated after the output of the differential amplifier circuit, in addition to the effect of claim 2, stable operation can be achieved even under the condition of large temperature change. It can be expected and the temperature characteristics can be easily matched.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a mounting position of an airbag control device according to an embodiment of the present invention to a vehicle body.

FIG. 2 is a characteristic diagram showing an output signal at the time of a side collision of the eddy current displacement sensor of the airbag control device according to the embodiment of the present invention.

FIG. 3 is a perspective view showing a state in which the airbag control device according to the embodiment of the present invention is attached to a passenger seat.

FIG. 4 is a control circuit diagram for controlling an airbag control device according to an embodiment of the present invention.

FIG. 5 is an output characteristic diagram of the detection circuit and the temperature compensation circuit of the airbag control device according to the embodiment of the present invention.

FIG. 6 is an output characteristic diagram of the differential amplifier of the differential amplification differentiating circuit of the airbag control device according to the embodiment of the present invention.

FIG. 7 is a control circuit diagram for controlling an airbag control device according to another embodiment of the present invention.

[Explanation of symbols]

 DS inflator squib DR rocker panel L inductance 10 side airbag control device 20 oscillation circuit 30 detection circuit 40 temperature compensation circuit 50 differential amplification differentiation circuit 60 integration comparison circuit 70 time limit circuit 80 self-diagnosis circuit

Claims (3)

[Claims] 1. An oscillation circuit in which a resonance condition is changed by an inductance that detects a relative change between a portion of a vehicle body that is displaced in the initial stage of collision and a portion that is difficult to be displaced, and detection and smoothing are performed to detect an oscillation state of the oscillation circuit. Detecting circuit, an output circuit for outputting a squib to fire when the magnitude of the differential value of the output of the detecting circuit is a predetermined value or more, and a self-diagnosis circuit for monitoring whether the oscillation circuit is in a stable oscillation state. And a time limit circuit for restraining the outputs of the output circuit and the self-diagnosis circuit until the time when the oscillation circuit is in a stable oscillation state. 2. An oscillation circuit whose resonance condition is changed by an inductance for detecting a relative change between a portion of the vehicle body that is displaced in the initial stage of collision and a portion which is difficult to be displaced, and detection and smoothing for detecting the oscillation state of the oscillation circuit. Detecting circuit, a temperature compensating circuit in which the connection conditions of the oscillation circuit and the transistor of the detecting circuit are matched, and the difference between the output of the detecting circuit and the output of the temperature compensating circuit is calculated, and the magnitude of the differential value thereof is calculated. Is output when the squib is higher than a predetermined value, an output circuit for firing the squib, a self-diagnosis circuit for monitoring whether the oscillation circuit is in a stable oscillation state, and the output until the time when the oscillation circuit becomes a stable oscillation state An air bag control device comprising: a circuit and a time limit circuit for restraining an output of the self-diagnosis circuit. 3. A differential amplifier circuit for matching the connection between the base and emitter of a transistor forming the oscillation circuit and the detection circuit with the connection between the base and emitter of the transistor for the temperature compensation circuit, and differentially amplifying the two. The air bag control device according to claim 2, wherein the temperature dependence of the oscillation circuit is canceled.