JPH08520B2 - 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.

[Prior art]

As a conventional vehicle occupant protection device, for example, there is one as shown in FIG. That is, in the figure, 101 is an acceleration sensor that detects a change in acceleration due to a collision of the vehicle and outputs the state as an analog signal, and 102 is a signal processing that integrates the acceleration signal related to the collision detection waveform from the acceleration sensor 101. An integrating circuit which is a circuit, 103 determines whether the integrated output from the integrating circuit 102 is equal to or higher than a predetermined level, and outputs a trigger signal when the output exceeds the predetermined level, 104 indicates a trigger from the comparing circuit 103. A signal is held for a predetermined time, and a drive circuit including a one-shot multivibrator that outputs a drive signal within the time, 105 is an igniter that is a passenger protection device main body that operates by receiving a drive signal from the drive circuit 4, When the ignition device 105 is driven, the occupant is protected by inflating the airbag or tensioning the seat belt. Thus, this conventional vehicle occupant protection device takes out a signal waveform of a certain level or more from the signal from the acceleration sensor 101, further passes the taken out signal waveform through the integrating circuit 102, and the integrated value is set in the comparator 103. When the predetermined level is exceeded, the occupant is protected by driving the ignition device 105 such as the airbag system, which is the body of the occupant protection device, to inflate the airbag and to tighten the seat belt.

[Problems to be Solved by the Invention]

However, in such a conventional vehicle occupant protection device, the distance between the human body and the airbag actually changes depending on the inclination angle with respect to the reclining seat on which the occupant sits. I couldn't. For example, in FIGS. 6 (A), (B) and (C), if 12 is a reclining seat (hereinafter simply referred to as a seat), 13 is a human body of an occupant, and 14 is a steering wheel, the normal state of FIG. On the other hand, in the case of FIG. 2B, the seat 12 is tilted at a shallow angle, so that the distance between the steering wheel 14 and the human body 13 is long. Also, in the case of FIG.
Since the 12 is tilted deeply, the distance between the steering wheel 14 and the human body 13 is longer than that in FIG. In this way, the distance between the steering body 14 provided with the airbag and the human body 13 changes depending on the inclination angle of the seat 12, so that in the conventional device, the human body is always inflated when the airbag is in the optimal inflated state at the time of a collision. There was a problem that it did not always hit the bag. The present invention has been made in view of such conventional problems, and an object thereof is to solve the above problems by controlling the airbag operation timing according to the inclination angle of the seat.

[Means for Solving the Problems]

An occupant protection device for a vehicle according to the present invention includes an acceleration sensor provided in a vehicle, and a human body movement amount prediction circuit that predicts a movement amount of a human body of an occupant after a predetermined time based on an acceleration signal obtained from the acceleration sensor. A comparison circuit for comparing a predicted value supplied from the human body movement amount prediction circuit with a reference value, and an occupant protection device operated based on the output of the comparison circuit when the predicted value exceeds the reference value. A main body, a detection means for detecting the inclination angle of the reclining seat provided in the vehicle, and lowering the reference value of the comparison circuit when the inclination angle is shallow according to the detection value of the detection means, and the inclination angle When the depth is deep, the control means is provided so as to increase the reference value. The control means connects a plurality of series circuits of a switching element and a resistor in parallel, and connects the resistance group to a power supply terminal through one resistor, and further performs the switching according to the output of the detection means. It has a control circuit for ON / OFF controlling the element. The reference value of the comparison circuit changes within a range in which the amount of change in the reference value is smaller than the amount of change in the seat when the tilt angle of the reclining seat is shallow, and when the tilt angle of the reclining seat is deep, the reference value of the reference value The change amount changes within a large range with respect to the change amount of the sheet. The resistance values of the resistances of the resistance group are set at a predetermined ratio.

[Action]

The detected value of the inclination angle of the seat detected by the detecting means in the present invention has a magnitude corresponding to the distance between the steering wheel and the human body, and the reference value is changed accordingly. The airbag operation timing is advanced, and when the inclination is deep, the airbag operation timing is delayed.

【Example】

An embodiment of the present invention will be described below in detail with reference to the drawings. First, the structure will be described. In FIG.
The acceleration sensor provided in the vehicle, 2 has a constant T _1, the first incomplete integrating circuit for integrating an acceleration signal of an analog output from the acceleration sensor 1, 3 and the first incomplete integrating circuit 2 A second incomplete integration circuit which has the same function and incompletely integrates the incomplete integration output from the first incomplete integration circuit 2 again, and the time constant T ₂ of the second incomplete integration circuit 3 is the first It is the same as the time constant T ₁ of the perfect integrating circuit 2. Reference numeral 4 is a first coefficient circuit made up of a first attenuator for adding a first coefficient to the detection output of the acceleration sensor 1, and 5 is a second coefficient circuit made up of a second attenuator having an attenuation rate of K. The circuit 5 adds the second coefficient to the integrated output of the first indefinite integration circuit 2. The attenuation rate of the first coefficient circuit 4 is 1/2 the square of the attenuation rate K of the second coefficient circuit 5. Further, the damping rate K is equal to the time t _d required after the ignition current is supplied to the ignition device 9 described later until the inflation of the airbag is completed. 6 is an adder circuit,
The adder circuit 6 adds the outputs from the second incomplete integration circuit 3, the first coefficient circuit 4 and the second coefficient circuit 5, and outputs the addition result. Reference numeral 7 is a comparison circuit for switching the output level to, for example, a high level when the addition output from the addition circuit 6 exceeds a predetermined reference value V _s , 8 is a drive circuit, 9
Is an ignition device which is the body of the passenger protection device.
Operates an airbag provided in, for example, a steering wheel based on the output of the drive circuit 8. Reference numeral 19 denotes a sensor as a detecting means for detecting the inclination angle of the seat 12, which generates a pulse signal according to the rotation of a motor (not shown) for inclining the seat 12. A control circuit 20 calculates a tilt angle based on the pulse signal from the sensor 19, and selectively generates A, B, and C control signals according to the tilt angle. 21,22,23 are transistors that are turned on / off by control signals A, B, C, and 24,25,26 are resistors connected between the collectors of the transistors 23,22,21 and one end of the resistor 10, respectively. Is. Here, each of the above resistors 10, 24, 25, 26
Resistance values of R ₁ , R ₂ , 2R ₂ and 4R ₂ are set at a predetermined ratio. Control circuit 20, transistors 21, 22, 23 and resistors
The control means is constituted by 10, 24, 25, 26 and the like. Further, the first incomplete integration circuit 2, the second incomplete integration circuit 3, the first coefficient circuit 4, the second coefficient circuit 5, the addition circuit 6 and the like constitute a human body movement amount prediction circuit. In FIG. 2, 15 is a seat belt, 16 is an airbag provided on the steering wheel 14, and an inflated state is shown. 17 is a seat belt retractor that winds the seat belt 15.
18 is a buckle for the seat belt 15. Next, the operation will be described. Various accelerations act on the vehicle as the vehicle travels. When the vehicle is traveling at a constant speed v ₀ , the acceleration sensor 1 detects an acceleration a (t) acting in the front-rear direction of the vehicle as shown in FIG. And the human body of the occupant, for example, the head, has a constant velocity v ₀
Meanwhile, the acceleration a (t) at that time also acts on the occupant. As a result, the head of the occupant begins to move at a certain relative speed V (t) (= ∫a (t) dt) with respect to the vehicle. The output a (t) of the acceleration sensor 1 at that time is integrated by the first incomplete integration circuit 2 to obtain the above V (t). Also,
When the position immediately before the collision is set as the initial position by moving the head of the occupant, x
It moves forward by (t) (= ∫V (t) dt). This displacement x (t) is obtained by integrating the output of the first incomplete integration circuit 2 by the second incomplete integration circuit 3, and the displacement amount of the occupant's head in real time is calculated. Next, the output V (t) of the first incomplete integration circuit 2 is weighted by t _d by the second coefficient circuit 5 to obtain V (t) × t _d , that is, the amount of displacement during the time t _d. . Further, the output a of the acceleration sensor 1
(T) is weighted by 1 / 2t _d ² by the first coefficient circuit 4 to obtain 1 / 2a (t) × t _d ² , that is, the amount of displacement during the time t _d . These outputs are added by the adder circuit 6 to obtain x (t) × V (t) × t _d + 1 / 2a (t) × t _d ² . This addition result indicates the predicted value x (t + t _d ) of the position of the occupant's head at time t _d after the present time t. This predicted value is supplied to the comparison circuit 7 and is shown in FIG.
When the position of the occupant's head deviates from the initial position 0 by x, that is, at time t ₁ , x (t + t _d ) exceeds the reference value V _s of the comparison circuit 7, and the ignition current is supplied to the ignition device 9. Activate the airbag and protect the occupant. That is, in FIG. 3 (B), when the position for operating the airbag or the like is set at a position separated from the initial position by a distance x corresponding to V _s , the actual head position is as shown by x (t). It can be seen that it operates at time t ₁ which is t _d earlier than time t _{2 when} x is reached. On the other hand, the sensor 19 generates a pulse signal in accordance with the inclination angle of the seat 12 in FIGS. 2 and 6, and the control circuit 20 produces control signals A, B, and B in response to the number of pulses as shown in FIG. C
Occurs. In the example shown in FIG. 4, the inclination angle is set from “0” to “7”.
The control signals A, B, and C are "1" or "0", respectively. Therefore, when the control signal A is "1", the transistor 21 is turned on and the resistor 26 is connected, and when the control signal B is "1", the transistor 22 is turned on.
Is turned on, the resistor 25 is connected, and the control signal C is "1".
At this time, the transistor 23 is turned on and the resistor 24 is connected. As a result, the combined resistance (composition of resistance values of the resistors 24, 25, 26) R connected to the comparison circuit 7 is as shown in FIG. The reference value V _S changes accordingly. For example, assuming that the inclination angle of the seat 12 is the size shown in FIG. 6 (B) and the stage is '7' in FIG. 4, all the control signals A, B, C become "1" at this time. , All the transistors 21,22,23 are turned on, all the resistors 24,25,26 are connected, and the combined resistance R is Becomes The reference value V _s in this case is Becomes Further, in the case of FIG. 6 (C), assuming that the inclination angle of the seat 12 is the stage of “1” in FIG. 4, the control signal A becomes “1”, the control signals B and C become “0”, and twenty one
Is turned on, the transistors 22 and 23 are turned off, the resistor 24 is connected, and the other resistors 25 and 26 are disconnected, and the combined resistor R
Becomes 4R ₂ . The reference value V _{s in} this case is V _s = V · 4R ₂ / (R ₁ + 4R ₂ ) ... (2). Further, assuming that the inclination angle in the case of FIG. 6 (A) is the stage of “4” in FIG. 4, at this time, the control signals A and B are “0”,
The output signal C becomes "1" and only the transistor 23 is turned on and only the resistor 24 is connected. Therefore, the combined resistance R is R ₂
Becomes The reference value V _{s in} this case is V _s = V · R ₂ / (R ₁ + R ₂ ) ... (3). Therefore, based on the above '4' stage, the sixth
In the case of FIG. 6B, V _s becomes small and the ignition timing to the ignition device 9 is advanced, and in the case of FIG. 7C, V _s becomes large and the ignition timing is delayed. According to the above, the steering 14 due to the inclination of the seat 12
When the distance between the human body 13 and the human body 13 is small, the reference voltage is lowered because it is necessary to accelerate the operating time of the airbag, and when the distance is large, the reference voltage is increased because the movement amount of the occupant is related to the operating time of the airbag. As a result, the airbag 16 starts to inflate at an appropriate timing, so that in the event of a vehicle collision, the human body always bumps into the airbag 16 when the airbag 16 is in the optimal inflated state to obtain the best cushion. You can

【The invention's effect】

As described above, according to the present invention, the movement amount of the human body of the occupant due to the collision is predicted, and the reference value to be compared with the predicted value is configured to be controlled according to the tilt angle of the reclining seat. At the time of a collision, the human body can always hit the airbag in an optimally expanded state regardless of the distance between the airbag and the human body, and the occupant can be protected more reliably than before. Further, since the control of the operation timing of the occupant protection device main body is performed by selecting the reference voltage by switching the resistance, the configuration can be simplified. Moreover, since the resistance value of the resistor is set at a predetermined ratio, the effect that the setting is easy 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 a perspective view of the system, and FIG. 3 (A) is an output waveform diagram of an acceleration sensor in the system. FIG. 4B is a diagram showing the predicted value and the actual measurement value of the human head when the acceleration in FIG. 3A is detected by the acceleration sensor, and FIG. 4 is the tilt of the reclining seat, the control signal, and the combined resistance. FIG. 5 is a block diagram showing a conventional vehicle occupant protection device, and FIG. 6 is a side view showing a change in the distance between the steering wheel and the human body due to the inclination of the seat. 1 ... Acceleration sensor, 2 ... First integrating circuit, 3 ... Second
Integrating circuit, 4 ... first coefficient circuit, 4 ... second coefficient circuit,
6 ... Addition circuit, 7 ... Comparison circuit, 9 ... Occupant protection device body, 12 ... Reclining seat, 19 ... Sensor, 20
...... Control circuit, 21,22,23 …… Transistor, 10,24,25,2
6 ... resistance.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kunihiro Kaneko 2-1910 Nisshin-cho, Omiya-shi, Saitama Kanto Seiki Co., Ltd. (56) Reference JP-A-2-38161 (JP, A) JP-A-49 -55031 (JP, A) Special table 63-503531 (JP, A)

Claims (4)

[Claims] 1. An acceleration sensor (1) provided on a vehicle,
A human body movement amount prediction circuit (2 to 6) that predicts a movement amount of a human body of an occupant after a predetermined time based on an acceleration signal obtained from the acceleration sensor, and a prediction value and a reference supplied from the human body movement amount prediction circuit. A comparison circuit (7) for comparing the value with
An occupant protection device body (9) which is operated based on the output of the comparison circuit when the predicted value exceeds the reference value;
The detection means (19) for detecting the inclination angle of the reclining seat provided in the vehicle, and lowering the reference value of the comparison circuit (7) when the inclination angle is shallow according to the detection value of the detection means, An occupant protection device for a vehicle, comprising control means (10), (20) to (26) for controlling to increase the reference value when the inclination angle is deep. 2. The control means connects a plurality of series circuits of switching elements and resistors in parallel, and connects the resistor group to a power supply terminal via one resistor, and further, the detection means (19). ) The switching element is turned on according to the output of
The vehicle occupant protection device according to claim 1, further comprising a control circuit for performing an OFF control. 3. The reference value of the comparison circuit (7) changes when the tilt angle of the reclining seat is shallow, within a range in which the amount of change in the reference value is smaller than the amount of change in the seat, and the tilt of the reclining seat. 2. The vehicle occupant protection system according to claim 1, wherein when the corner is deep, the amount of change in the reference value changes within a large range with respect to the amount of change in the seat. 4. The vehicle occupant protection system according to claim 2, wherein the resistances of the resistance groups are set in a predetermined ratio.