JPH07112807B2 - Vehicle occupant protection device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a vehicle occupant protection device that protects an occupant in the event of a vehicle collision.

2. Description of the Related Art As a conventional vehicle occupant protection device, for example, there is one as shown in FIG. That is, in the figure, 1 is an acceleration sensor that detects an acceleration signal at the time of a vehicle collision, 2 is an integration circuit that is a signal processing circuit that integrates the acceleration signal related to the collision detection waveform from the acceleration sensor 1, and 3 is this integration circuit. The comparator circuit 4 which judges whether the integrated output from the circuit 2 is equal to or higher than a predetermined level and outputs a trigger signal when the level exceeds the predetermined level, holds the trigger signal from the comparison circuit 3 for a predetermined time, and within that time. Is a drive circuit composed of a one-shot multivibrator that outputs a drive signal, and 5 is an ignition device that is a main body of an occupant protection device that operates by receiving the drive signal from the drive circuit 4. When the ignition device 5 is driven, an airbag is driven. The occupants were protected by inflating the vehicle and tightening the seat belt.

However, in such a conventional vehicle occupant protection device, attention is paid to the integrated value of the output signal waveform from the acceleration sensor 1, and the occupant is in a serious state due to changes over time. Since the comparison circuit 3 determines whether or not a collision accident has occurred and the drive circuit 4 including the one-shot multivibrator is operated by the trigger signal, the drive circuit 4 can be reliably operated when the pulse width of the trigger signal is small. However, there was a problem that the reliability of occupant protection in an emergency was low. The present invention has been made to solve the above problems, and an object of the present invention is to obtain a vehicle occupant protection device that reliably operates the occupant protection device main body when a trigger signal is issued from the comparison circuit. To do.

[Means for Solving the Problems]

A vehicle occupant protection system according to the present invention integrates an acceleration signal from the acceleration sensor to predict a displacement amount of an occupant's body after a predetermined time, and a predicted displacement from the displacement amount prediction circuit. A comparator circuit that detects that the amount has reached a predetermined amount and outputs a trigger signal, and a latch circuit that latches the trigger signal from this comparator circuit and supplies an ignition signal to the passenger protection device body Is.

[Work]

The vehicle occupant protection device according to the present invention is designed to reliably operate the occupant protection device body by predicting the time until the occupant hits a part of the body on the steering wheel or the like from the acceleration waveform at the time of a vehicle collision. is there.

【Example】

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, the same or equivalent components as in FIG. First of all, in the figure, 1 is an acceleration sensor that detects a change in acceleration due to a collision of a vehicle and outputs the state as an analog signal, and 2a has a time constant T ₁ and is output from the acceleration sensor 1. A second incomplete integrator circuit for integrating the analog signal, 2b has the same function as the first incomplete integrator circuit 2a, and a second incomplete integrate for the incomplete integral output from the first incomplete integrator circuit 2a. Incomplete integration circuit, this second
The time constant T ₂ of the incomplete integration circuit 2b is the same as the time constant T ₁ of the first incomplete integration circuit 2. Reference numeral 6 is a first coefficient circuit including a first attenuator for adding a first coefficient to the detection output of the acceleration sensor 1, and 7 is a second coefficient circuit including a second attenuator having an attenuation rate of K. The circuit 7 adds the second coefficient to the integrated output of the first incomplete integration circuit 2a. The attenuation rate of the first coefficient circuit 6 is 1 / the square of the attenuation rate K of the second coefficient circuit 7.
Is 2. Incidentally, the attenuation ratio K is equal to the time t _d required from the supply of the ignition current to the ignition apparatus described later until the expansion of the airbag is completed. An adder circuit 8 adds the outputs from the second incomplete integration circuit 2b, the first coefficient circuit 6 and the second coefficient circuit 7, and outputs the result. Then, the first and second integration circuits 2a, 2
b, the first and second coefficient circuits 6 and 7 and the adder circuit 8 form a signal processing circuit. Reference numeral 9 is a latch circuit that latches the trigger signal from the comparison circuit 3, and operates the ignition device 5 based on the output of the latch circuit 9, for example, an airbag and a preloader. Next, the operation will be described. Various accelerations act on the vehicle as the vehicle travels.
Now, when the vehicle is traveling at a constant speed Vo, for example, due to a collision, an acceleration a (t) acts in the front-rear direction of the vehicle as shown in FIG. 2 (A), which is detected by the acceleration sensor 1. Then, the occupant's head is thrown out at a constant speed Vo, while the acceleration a (t) at that time also acts on the occupant. This allows the head to move at a certain speed relative to the vehicle
That is, the movement starts at V (t) (= ∫a (t) dt). On the other hand, the output a (t) of the acceleration sensor 1 at that time is integrated by the first incomplete integration circuit 2a. Further, when the head starts to move and the position immediately before the collision is set as the initial position, the head is displaced forward by x (t) (= ∫V (t) dt) as time elapses. This displacement x (t) is the second incomplete integration circuit.
The output of the first incomplete integration circuit 2a is integrated by 2b to obtain the value, and the displacement x (t) of the occupant's head in real time is calculated. Next, the output V (t) of the first incomplete integration circuit 2a
Is weighted by t _d by the second coefficient circuit 7, and V (t)
× t _d , that is, the amount of displacement during the time t _d is obtained. Further, the output a (t) of the acceleration sensor 1 is weighted by 1 / 2t ² _d by the first coefficient circuit 6, and 1 / 2a (t) ×
t _d , that is, the amount of displacement during the time t _d is obtained. These outputs are added by the adder circuit 8 and x
(T) + V (t) × t d + 1 / 2a (t) × t 2 d is obtained. That is, this corresponds to the predicted value x (t + t _d ) of the position of the head of the occupant at the time t _d after the present time. This predicted value x (t + t _d ) is supplied to the comparison circuit 3, and when the position of the occupant's head is displaced from the initial position 0 by x in FIG. 2 (B), that is, x (t + t _d ) at time t ₁ . When the threshold x of the comparison circuit 3 is exceeded, the trigger signal is latched by the latch circuit 9 to supply the ignition current to the ignition device 5.
Activate the airbag and protect the occupant. That is, in FIG. 2 (B), if the position for operating the airbag is set to a position separated from the initial position 0 by X, x
As shown in (t), it can be seen that the head operates at time t ₁ which is t _d faster than time t _{2 at} which the head position actually reaches x. A circuit diagram embodying the vehicle occupant protection system according to the present invention is shown in FIG. 3, in which the same parts as those in FIG. 1 are designated by the same reference numerals, and 10 is the input of the first incomplete integration circuit 2a. Since the polarity is inverted with respect to
It is a polarity inverting circuit provided for inputting to the incomplete integration circuit 2b. Further, in FIG. 3, the coefficient of the second coefficient circuit 7 is set to 1, so that the circuit element is not shown.

【The invention's effect】

As described above, according to the present invention, the configuration thereof includes an acceleration sensor that detects an acceleration signal at the time of a collision of a vehicle, and an acceleration signal from the acceleration sensor is integrated to obtain a displacement amount of a body of an occupant after a predetermined time. A displacement amount prediction circuit for predicting, a comparison circuit that outputs a trigger signal by detecting that the predicted displacement amount from the displacement amount prediction circuit has reached a predetermined amount, and a trigger signal from this comparison circuit are latched. Since the vehicle occupant protection device is characterized in that the occupant protection device main body is provided with a latch circuit that supplies an ignition signal, it is possible to predict in advance the amount of displacement of the occupant's body in a collision at a predetermined time after the collision. Since the ignition signal can be reliably generated, it is possible to set the occupant's head to collide with the airbag when the airbag is inflated to the maximum. Cormorants effect can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a vehicle occupant protection system according to an embodiment of the present invention, FIG. 2 is an output waveform diagram of an acceleration sensor at the time of a collision, and FIG. 3 is a circuit embodying an embodiment of the present invention. 4 and 5 are block diagrams showing an example of a conventional vehicle occupant protection device. 1 ... Acceleration sensor, 2a ... 1st integrating circuit, 2b ... 2nd
Integrator circuit, 3 ... Comparison circuit, 5 ... Passenger protection device body,
6 ... First coefficient circuit, 7 ... Second coefficient circuit, 8 ... Adder circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kim, Kaoru, 2-1910 Nisshin-cho, Omiya-shi, Saitama Kanto Seiki Co., Ltd. (72) Kunihiro Kaneko 2-1910 Nisshin-cho, Omiya-shi, Saitama Kanto Within Seiki Co., Ltd. (72) Inventor Katsuji Ohneda 2-1910, Nisshin-cho, Omiya City, Saitama Kanto Seiki Co., Ltd. (56) Reference JP-A-49-55031 (JP, A) International Publication 90-2062 ( WO, A) International publication 90-9298 (WO, A)

Claims (1)

[Claims] 1. An acceleration sensor (1) for detecting an acceleration signal at the time of a vehicle collision, and a displacement amount prediction circuit for integrating the acceleration signal from the acceleration sensor to predict the displacement amount of a passenger's body after a predetermined time. (2a, 2b, 6,7,8) and detecting that the predicted displacement amount from the displacement amount prediction circuit has reached a predetermined amount,
A comparison circuit (3) that outputs a trigger signal, and a passenger signal protection device body (5) by latching the trigger signal from this comparison circuit
And a latch circuit (9) for supplying an ignition signal to the vehicle occupant protection device.