JP3529252B2 - Airbag 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 air bag device used in a vehicle such as an automobile, and more particularly to an air bag device capable of controlling the operation of the air bag in accordance with the physique of a seated person.

[0002]

2. Description of the Related Art Recently, automobiles and the like have come to be equipped with an airbag device for protecting a seated person from a collision accident.
The airbag device is designed to prevent the seated person from falling forward by inflating the airbag in a balloon shape by detecting the impact at the time of collision and exploding the detonator. The airbag is stored in the central portion of the steering wheel on the driver's side, and is stored in the instrument panel on the passenger's side.

However, since a general airbag device operates regardless of the size of the seated person, it may not always be possible to ensure the safety of the seated person. For example, when a small person such as a woman is driving, the face approaches the steering wheel, and the airbag is inflated, and the face is injured. When a small person such as a child or a woman in particular is seated in the passenger seat, the head faces the instrument panel storing the airbag, and the head is strongly pressed by the deployed airbag. Sometimes.

Therefore, conventionally, there has been proposed an airbag device in which a sensor for calculating the weight of the seated person is installed in the seated portion and the deployment of the air bag can be controlled according to the size of the seated person.

[0005]

In the conventional airbag device described above, when the angle of the backrest is changed, the load applied to the seating portion changes. Therefore, the weight is measured to measure the weight of the seated person. The sensor cannot accurately calculate the weight simply by installing the sensor for calculation on the seating portion. Therefore, the airbag cannot be deployed according to the physique of the occupant only by installing the sensor for calculating the weight of the occupant in the seat portion.

Therefore, another method has been proposed in which the angle of the backrest is separately measured to correct the measured value of the load applied to the seating portion. The angle of the backrest can be measured by providing a special device if it is a power seat used in a luxury car.

However, it is difficult to correct the angle of the backrest in a mass car that does not employ a power seat because the angle of the backrest cannot be measured. Even if the backrest angle is measured and the load measurement value is corrected, if the seated person changes his / her posture such as crossing the legs, pushing the legs, or erecting the knees, the weight will be accurately measured. There is a problem that it cannot be calculated, and an adult is determined to be a child.

The present invention has been made in order to solve the above-mentioned problems, and it is possible to control the operation of the airbag by accurately determining the physical constitution of the seated person without being affected by the sitting posture. An object is to provide a bag device.

[0009]

SUMMARY OF THE INVENTION An airbag device of the present invention comprises a pressure-sensitive sensor provided in a seating portion of a seat, and a pressure sensor for measuring the pressure distribution of the seating portion, so that the pressure sensor is placed under the buttocks of a seated person. A physical constitution determination means for determining the physical constitution of the seated person based on the distance between the two recognized pressure peaks; and a control means for controlling the operation of the airbag based on the result determined by the physical constitution determination means. It is a feature.

According to the present invention, the physical constitution of the seated person is determined based on the distance between the two pressure peaks observed under the buttocks of the seated person, so that the seated posture of the seated person is not affected. It is possible to accurately determine the physique and control the operation of the airbag.

The pressure-sensitive sensor may include a sensor element whose electric resistance value changes according to pressure.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An airbag device of the present invention will be described below with reference to the drawings. As shown in FIG. 1, an airbag device according to the present invention is provided with a sensor device 2 provided inside a seating portion 1 of a seat and whether or not an airbag 3 is deployed.
And a control unit 4 for controlling operations such as explosive force, deployment speed, and deployment direction.

The sensor device 2 measures a pressure sensor 5 for detecting the seat pressure of the seated occupant T, and a pressure distribution from the seat pressure detected by the pressure sensor 5, which is recognized under the buttocks of the seated occupant T. The processing unit 6 determines the physique of the seated occupant T based on the distance between the two pressure peaks.

The pressure sensor 5 is attached to a portion slightly inside the surface of the seat 1. As shown in FIGS. 2 and 3, the pressure-sensitive sensor 5 includes transparent plastic films 10 and 11, row electrodes 12 printed on the upper plastic film, and columns printed on the lower plastic film. The electrodes 13 and the sensor elements 14 provided at the intersections between the row electrodes 12 and the column electrodes 13.

Examples of plastics used for the plastic films 10 and 11 include polyethylene terephthalate (PET) and polyethylene naphthalate (P).
EN), polyetherimide (PEI), polyimide (PI), polyphenylene sulfide (PPS), polyethersulfone (PES), polyetheretherketone (PEEK), polyarylate (PAR), polyamideimide (PAI), polypara. Phenylene terephthalamide (PPTA), PTFE, PVDF, PF
Fluorine resin such as A, FEP, ETFE, polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PV
C) etc.

The row electrodes 12 and the column electrodes 13 are formed by printing a conductive ink containing a metal powder such as silver powder or copper powder as a main component on the plastic films 10 and 11 by a known printing means. In addition, in FIG. 2, lead wires (not shown) are drawn out from the row electrodes 12 and the column electrodes 13.
And is connected to the processing unit 6.

The sensor element 14 is composed of a pressure-sensitive ink 15 applied or printed on the upper plastic film 10 and a pressure-sensitive ink 16 applied or printed on the lower plastic film 11. The pressure-sensitive inks 15 and 16 are made of a substance containing semiconductive particles so that they exhibit high resistance (insulation) in a non-pressurized state and their resistance value changes according to the magnitude of the pressure as they are pressed. To be Pressure sensitive ink 1
Since the surface of each of the pressure-sensitive inks 5 and 16 has an uneven portion, a void portion 17 is formed between the pressure-sensitive inks 15 and 16 at a certain distance in order to prevent the pressure-sensitive inks 15 and 16 from adhering to each other.

Adhesive layers 18 are provided between the row electrodes 12 and the lower plastic film 11 and between the column electrodes 13 and the upper plastic film 10.

When pressure is applied to the pressure-sensitive sensor 5, the upper and lower pressure-sensitive inks 15 and 16 come into contact with each other, and the electrical resistance between them changes. Therefore, the change is detected to measure the pressure distribution of the seating portion 1. You can

In the pressure distribution measured by the pressure sensitive sensor 5, two pressure peaks are recognized under the buttocks as shown in FIG. This pressure peak is known to appear below the ischial tuberosity. In general, in the relationship between the value of the pressure peak and the physical characteristics, it is known that there is no significant correlation between height, weight, Laurel index, and maximum thigh outer diameter (Journal of Japanese Society for Paraplegia Medicine VOL7 , P114, 1994). This is because the angle between the seat surface and the pelvis, that is, the shape of the ischial tuberosity part is sharp and narrow in the anterior part, so as the pelvis leans forward, the grounding point of the ischial tuberosity also moves to the anterior part and the pressure peak. This is because the value of becomes large. Therefore, the physical characteristic (weight) of the occupant T cannot be obtained from the value of the pressure peak.

Further, when a child of a small size sits deeply, the front end of the seating portion 1 is hit by an inflation (belly) or a shin (shin), which causes the knee to float in the air. The side is barely pressurized. Therefore, the weight of the seated person cannot be accurately obtained from the load applied to the seating surface.
Similarly, when an adult sits upright on his knees, the lower part of the thigh is not pressed.

Therefore, in the present invention, attention is paid to the distance between the two pressure peaks observed in the pressure distribution of the seating portion 1, the distance is measured by the processing unit 6, and the size of the pelvis lower part of the seated person T is determined. By making a determination, the physique of the seated occupant T is determined from this measured value. Here, the physique information to be determined includes, for example, height, weight, Laurel index, and Body Mass Index.
It is an index indicating the degree of obesity such as ex.

The distance between the pressure peaks can be obtained from the position of the sensor element 14 showing the peak value in the measurement data. However, if the sensor elements 14 are installed in a discrete manner, the installation interval of the sensor elements 14 influences the height determination accuracy. Therefore, it is preferable to install many sensor elements 14 densely. When the interval between the sensor elements 14 is rough, curve fitting is performed on the profile measurement data between the pressure peaks, and the height of the seated occupant T is obtained by setting the peak distance of the obtained approximation curve to the seat pressure peak-to-peak distance. It is also possible.

Further, the hip width is determined by the degree of obesity (Laurel index and
It is also related to the Body Mass Index), and the obesity degree of the seated person T can also be obtained by combining it with the case where the height is determined from the distance between the pressure peaks. Furthermore, the weight can be determined from the height and an index indicating the degree of obesity.

As described above, the processing unit 6 for determining the physical constitution of the occupant T is connected to the control unit 4 such as a computer for controlling the operation of the airbag 3 as shown in FIG. An impact detection sensor 7 and a detonator 8 that detonates the airbag 3 are connected to the control unit 4. When the impact detection sensor 7 detects an impact, the detonator 8 explodes and the airbag 3 deploys.

The control unit 4 inputs information about the physique of the occupant T determined by the processing unit 6 of the sensor device 2,
Based on the information, the presence or absence of deployment of the airbag 3, the explosive force, the deployment speed, the deployment direction, etc. are determined. At that time, for example, the physique of the seated occupant T is classified into three stages of large, medium, and small, and the above items are determined according to the classified class. The determined items are sent to the detonator 8 as an airbag control signal. The detonator 8 operates the airbag 3 based on the airbag control signal.

The air bag device according to the present invention is configured as described above, so that the air bag 3 can be deployed according to the physique of the seated person T. Therefore, for example, when it is determined that a small woman is seated in the driver's seat, the airbag 3 is deployed at a slow speed, and when it is determined that a small child is seated in the passenger seat, the airbag is inflated. The bag 3 can be prevented from unfolding.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of technical matters described in the claims. For example, by arranging the pressure-sensitive sensor 5 also in the backrest 9 and using it together with the pressure-sensitive sensor 5 arranged in the seat portion 1, it is possible to more accurately determine the physique of the seated person T.

[0029]

EXAMPLE The inventor of the present application measured the pressure distribution using the pressure-sensitive sensor 5 having 44 × 27 sensor elements 14 arranged in a matrix in the seating portion 1 of the seat. The interval between the sensor elements 14 is 1 cm. Also,
The angle of the seat rest is kept constant, and the seated person T is seated while fixing the seating posture so that the seated person T can sit back.

FIG. 5 is a graph showing the relationship between the distance between the peaks of the pressure distribution of the sensor device 2 and the height. As can be seen from FIG. 5, there is a correlation between the peak-to-peak distance of the pressure distribution and the height, and it can be seen that the height can be obtained from the peak-to-peak distance of the pressure distribution. This time, the error between the height determined based on the regression equation obtained from the obtained data and the value measured by the height meter was ± 20 cm or less. Therefore, it is classified according to height (tall, middle, short, etc.)
It is possible to determine which class the occupant T is to be classified into.

FIG. 6 is a graph showing the relationship between the weight applied to the sensor element (sum of seating surface sensor outputs) and weight. Figure 6
As can be seen from the above, there is a correlation between the load applied to the sensor element 14 and the weight of the seated occupant T.
The occupant's T weight can be calculated from the load applied to the occupant.
If the angle of the backrest 9 is constant, the load applied to the seat 1 and the weight are proportional. The reason why the sum of the output from the seating sensor and the inclination of the body weight change around 50 kg is that the body weight 50
It is considered that when an adult weighs about kg or more, the sitting buttocks width becomes wider than the installation area of the sensor, and the specific gravity of the load not detected by the sensor becomes high. Therefore, when the correlation coefficient is calculated from the data of adults and children weighing 50 kg or less, R
It was found to have a strong correlation with = 0.81. Further, the error between the judged body weight and the actual body weight measured by the scale was ± 7 kg or less.

Table 1 shows load values and peak-to-peak distances when the angle of the backrest hackrest is changed. The peak-to-peak distance was calculated by calculating an approximate curve.

[0033]

[Table 1] As can be seen from Table 1, although the angle of the backrest has a great influence on the load, the peak-to-peak distance does not change significantly even if the sitting posture changes, and therefore it can be said that the height can be obtained from the peak-to-peak distance.

[0034]

According to the present invention, the physique of the seated person is determined based on the distance between the two pressure peaks observed under the buttocks of the seated person, so that the seated posture is not affected by the seated posture of the seated person. It is possible to accurately determine the physical constitution of the person and control the operation of the airbag.

Therefore, for example, when it is judged that the seated person is of a small size, the inflation speed of the airbag is adjusted to a low speed or the airbag is not deployed, so that the infant or the body size sitting on the seat is reduced. It is possible to prevent an accident in which a small woman in an air bag is pressed by an airbag.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an airbag device according to the present invention.

FIG. 2 is a schematic plan view showing a pressure-sensitive sensor that constitutes an airbag device according to the present invention.

FIG. 3 is a cross-sectional view showing a pressure-sensitive sensor that constitutes an airbag device according to the present invention.

FIG. 4 is an explanatory diagram showing a three-dimensional pressure distribution in a seat portion.

FIG. 5 is a graph showing the relationship between the distance between pressure peaks and height.

FIG. 6 is a graph showing the relationship between the weight applied to the sensor element (sum of seating surface sensor outputs) and weight.

[Explanation of symbols]

T: Seated 1: Seat 2: Sensor device 3: Airbag 4: Control unit 5: Pressure sensor 6: Processing unit (physical structure determination means) 7: Impact detection sensor 8: Detonator 14: Sensor element

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-196006 (JP, A) JP-A-7-285364 (JP, A) JP-A-5-139233 (JP, A) JP-A-7- 186880 (JP, A) JP 10-175471 (JP, A) JP 11-99901 (JP, A) JP 2-38164 (JP, A) JP 2001-502986 (JP, A) JP Table 2001-509109 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60R 21/16-21/32 B60N 2/44

Claims (2)

(57) [Claims] 1. A pressure-sensitive sensor provided on a seating portion of a seat,
The pressure sensor measures the pressure distribution in the sitting portion, and the physique determining means for determining the physique of the sitting person based on the distance between the two pressure peaks observed under the buttocks of the occupant, and the physique determining means. A control means for controlling the operation of the airbag based on the result of the above. 2. The airbag device according to claim 1, wherein the pressure-sensitive sensor includes a sensor element whose electric resistance value changes according to pressure.