JPH10236274A - Occupant detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a body weight signal having desired accuracy by arranging pressure sensors in a seat and a seat back part, correcting its detecting outputs by detecting output of an angle sensor to detect a reclining angle, adding these corrected detecting outputs of the pressure sensors, and detecting body weight of a seated person. SOLUTION: Nonextensible/noncontractible air bags 21e and 21f are arranged in a seat part 21 in a seat 20, and its air pressure is detected by a first pressure sensor 23, and a nonextensible/noncontractible air bag is similarly arranged in a seat back part 22, and its air pressure is detected by a second pressure sensor 24. A falling-down angle of the seat back part 22 is detected by an angle sensor 25. Respective detecting outputs of the first and the second pressure sensors 23 and 24 are corrected by detecting output of the angle sensor 25 by an occupant detecting circuit 26, and its results are added together, and body weight of a seated person is detected. An acceleration signal detected by an acceleration sensor 27 is supplied to an unfolding judging circuit 28, and a detonator of an air bag module for a front passenger seat is ignited by an unfolding signal through a driving circuit 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant detection device used for measuring the weight of a person sitting on a reclining seat or the like.

[0002]

2. Description of the Related Art As an occupant detection device of this type, there is, for example, an occupant restraint system disclosed in Japanese Patent Application Laid-Open No. 7-186880, which will be described below with reference to FIGS. That is, in FIG. 13 and FIG. 14, when the occupant sits on the seat 2 of the seat 1,
A weight sensor 3 using a plurality of strain gauges 3a buried therein detects the weight of the occupant, and a signal indicating the detected weight is supplied to the control device 4. The control device 4
, A signal detected by an angle sensor 6 for detecting a reclining angle of the backrest 5 of the seat 1 is input, and based on the signal, a signal supplied from the weight sensor 3 is corrected by the control device 4, When the actual weight of the seated occupant is calculated and it is determined that the occupant is not seated, the control device 4 does not supply an ignition current to the primer 7. As a result, the inflator 8 does not operate, and the airbag 9 does not deploy as indicated by reference numeral 10.

On the other hand, when the control device 4 determines that the occupant is seated on the seat 1 based on the signals from the weight sensor 3 and the angle sensor 6, it is determined that a collision has occurred from the collision sensor 11. When the acceleration signal is supplied, the magnitude of the collision is determined based on the supplied acceleration signal.
Supplies an ignition current to the primer 7 and activates the inflator 8 to deploy the airbag 9 as indicated by reference numeral 10 to protect the occupant. In FIG. 13, reference numeral 12 denotes a vehicle, and 13 denotes an instrument panel, on which the primer 7, the inflator 8, the airbag 9, and the like are unitized and mounted.

[0004]

However, such an occupant detection device has a structure in which the weight sensor is provided only on the seat portion of the seat. Therefore, the signal from the weight sensor is used to recline the backrest portion. Although the angle is corrected by the angle signal from the angle sensor for detecting the angle, the weight applied to the backrest 5 cannot be detected, so there is a limit to this, and there is a problem that it is difficult to easily obtain the desired accuracy. .

The present invention has been made in view of such a problem, and corrects a signal from a seat portion and a backrest portion of a seat with a reclining angle, and based on the corrected signal, obtains a weight with a desired accuracy. The purpose is to get a signal.

[0006]

According to a first aspect of the present invention, a pressure sensor is provided on each of the seat and the backrest of a seat having a reclining function in which the angle of the backrest with respect to the seat can be adjusted. With the provided, an angle sensor for detecting the reclining angle is provided, the detection output from each pressure sensor is corrected with the detection output from the angle sensor, and the corrected detection output of the pressure sensor is added. The weight of a person sitting on the seat is detected.

A second invention is characterized in that the pressure sensor according to the first invention comprises an air bag and a pressure sensor main body for detecting an air pressure in the air bag.

A third invention is characterized in that the air bag of the pressure sensor according to the second invention is arranged between the S-shaped spring of the seat and an elastic member for forming a seat surface.

A fourth invention is characterized in that the air bag of the pressure sensor according to the second invention is arranged between the elastic member for forming the seat surface of the seat and the seat support structure.

A fifth invention is characterized in that the air bladder of the pressure sensor according to the third and fourth inventions is divided into a plurality of parts and arranged on the seat and the backrest of the seat, respectively.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. An embodiment according to the present invention will be described below with reference to FIGS. Reference numeral 20 denotes a seat such as a passenger seat, which includes a seat portion 21 and a backrest portion 22. The seat portion 21 has a seat frame 21a, a seat frame 21b, and a seat frame 21b as shown in the cross-sectional explanatory view of FIG. A plurality of non-stretchable air between the seat frame 21b and the seat pad 21d and between the S-shaped spring 21c and the seat pad 21d. Bags 21e and 21f are interposed, and the air bags 21e and 21f are connected by pipes 21g and 21h, respectively, and are detected by the first pressure sensor 23 as one air pressure.

The backrest 22 is also composed of a backrest frame 22a, a backrest frame 22b, an S-shaped spring 22c, a backrest pad 22d, etc., between the S-shaped spring 22c and the backrest pad 22d. A plurality of non-stretchable air bladders 22e are interposed,
Each air bag 22e is connected by a pipe 22f, and is detected as one air pressure by the second pressure sensor 24.

The S-shaped spring 21 as described above
In the seat 20 shown in FIGS. 5 and 6 (equivalent to that shown in FIGS. 3 and 4 and denoted by the same reference numerals) to which the c and 22c are not attached,
e and 21f are interposed only between the seat frame 21b and the seat pad 21d, and the air bag 22e of the backrest 22 is interposed between the backrest frame 22b and the backpad 22d. Needless to say.

An angle sensor 25 detects the reclining angle of the seat 20, that is, the tilt angle of the backrest 22. Reference numeral 26 denotes an occupant detection circuit, which inputs respective signals from the first pressure sensor 23, the second pressure sensor 24, and the angle sensor 25, and outputs respective detection outputs from the first and second pressure sensors 23, 24. The weight W of the person seated on the seat 20 is detected based on the following equation by correcting with the detection output from the angle sensor 25 and adding the corrected results. W = (K1 · a + K2 · b) · c a: output of the first pressure sensor 23 b: output of the second pressure sensor 24 c: coefficients K1, K2: function of reclining angle The calculated weight W is a predetermined value. When it is determined that the value is equal to or more than, for example, 30 kg, a signal indicating that a person is seated is output.

Reference numeral 27 denotes an acceleration sensor, which corresponds to the impact sensor 11 shown in FIG. 13, detects an acceleration generated at the time of a collision of the vehicle 32, and supplies an acceleration signal corresponding to the detected acceleration to a deployment judgment circuit 28 described later. Expansion judgment circuit 28
Is supplied from the occupant detection circuit 26 to the seat 20, a signal indicating that a person having a predetermined weight or more is seated, and receives an acceleration signal from the acceleration sensor 27, If it is determined that a serious collision accident has occurred based on the signal, the deployment signal
An ignition current is supplied to a primer (indicated by reference numeral 7 in FIG. 13) constituting the passenger-seat airbag module 30 through 9 to deploy the airbag. It goes without saying that the passenger seat airbag module 30 is composed of the same components as the primer 7, the inflator 8, the airbag 9, and the like in FIG.

With the above configuration, when a person sits on the seat 20, the weight of the person is reduced by the seat 2 of the seat 20.
The weight is converted to air pressure by the air bags 21e, 21f, 22e buried in the airbags 21e, 21f, 22e, respectively, which are supported by the first and the backrest portions 22, and the converted air pressures are respectively connected to the first and second pressure sensors 23 connected thereto. , 24 are converted into electric quantities. This means that if the weight is the same, no matter what angle the seat 20 is reclined and no matter what posture the seat 20 is seated in, the same amount of electricity is detected. For example, as shown in FIG. 8, as typical examples, (1) when sitting in a good posture, (2) when the occupant is seated as shown in FIG. As shown in FIG.
The occupant may also lean on the backrest 22 or the like, and in any case, the occupant detection circuit 26 detects the weight of the seated person.

That is, when the reclining angle θ of the seat 20 is changed as shown in FIG. 11, the characteristics shown in FIG. 12 are obtained by the first and second pressure sensors 23 and 24. The occupant detection circuit 26 calculates the weight of the seated person based on the above-mentioned equation based on the obtained signals indicating the pressures from both sides. When it is determined that the calculated weight is equal to or greater than the predetermined value, the occupant detection circuit 26 uses the airbag to protect the seated person based on the acceleration signal from the acceleration sensor 27. A signal for permitting signal output when an ignition signal is generated is output.

[0018]

As described above, according to the present invention, the signals from the seat portion and the backrest portion of the seat are corrected by the reclining angle, and a weight signal having a desired accuracy is obtained based on the corrected signals. The effect that can be performed is exhibited.

Further, by using a plurality of simple air bags for the pressure sensor, it is possible to realize low cost, and it is possible to obtain effects such as being hard to break and easy to handle.

Further, since the pressure sensor is an air bag, it is only necessary to sandwich the pressure sensor between the S-shaped spring and the elastic member for forming the seat surface and between the elastic member for forming the seat surface and the seat supporting structure plate, so that the installation is possible. Effects such as easiness are exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an entire occupant protection device according to an embodiment of the present invention.

FIG. 2 is a sectional explanatory view when an air bag is attached to a seat having an S-shaped spring.

FIG. 3 is an explanatory sectional view of a main part of the seat shown in FIG. 2 as viewed from the front.

FIG. 4 is an explanatory sectional view of a main part of the seat shown in FIG. 2 as viewed from above.

FIG. 5 is an explanatory sectional view when an air bag is attached to a seat having no S-shaped spring in FIG. 2;

6 is an explanatory sectional view of a main part of the seat shown in FIG. 5 as viewed from the front.

7 is an explanatory cross-sectional view of a main part of the seat shown in FIG. 5 as viewed from above.

FIG. 8 is an explanatory diagram showing that a force applied to a seat portion and a backrest portion when the user sits on the seat in a normal posture is divided.

FIG. 9 is an explanatory view showing that weight is applied only to the seat portion when the backrest portion of the seat is tilted, and not to the backrest portion.

FIG. 10 is a diagram for explaining that the force applied to the seat and the backrest when a person leans on the backrest when the backrest of the seat is tilted is divided.

FIG. 11 is an explanatory diagram for defining a reclining angle θ of a seat.

FIG. 12 is a characteristic diagram illustrating a relationship between a reclining angle θ and voltages output from first and second pressure sensors.

FIG. 13 is an explanatory diagram of the entire conventional occupant protection device.

FIG. 14 is an explanatory diagram for explaining the weight sensor in FIG. 13;

[Explanation of symbols]

 Reference Signs List 20 seat 21 seat 21a seat frame 21b seat frame 21c, 22c S-shaped spring 21d seat pad 21e, 21f, 22e air bag 21g, 21h, 22f pipe 22 backrest 22a backrest frame 22b backrest frame 22d Backrest pad 23, 24 Pressure sensor 25 Angle sensor 26 Occupant detection circuit 27 Acceleration sensor 28 Deployment judgment circuit 30 Airbag module for passenger seat

Claims (5)

[Claims] 1. A pressure sensor is provided for each of the seat and the backrest of a seat having a reclining function in which the angle of the backrest with respect to the seat is adjustable, and an angle sensor for detecting the reclining angle is provided. The detection output from the pressure sensor is corrected by the detection output from the angle sensor, and the corrected detection output from the pressure sensor is added to detect the weight of the person sitting on the seat. Occupant detection device. 2. The occupant detection device according to claim 1, wherein the pressure sensor comprises an air bag and a pressure sensor main body for detecting an air pressure in the air bag. 3. The occupant detection device according to claim 2, wherein the air bladder of the pressure sensor is disposed between an S-shaped spring of the seat and an elastic member for forming a seat surface. 4. The occupant detection device according to claim 2, wherein the air bladder of the pressure sensor is disposed between a seat surface forming elastic member of the seat and a seat support structure. 5. The occupant detection device according to claim 3, wherein the air bladder of the pressure sensor is divided into a plurality of parts and arranged on each of a seat portion and a backrest portion of the seat.