JP2000241268A - Seating detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a practical seating detector by fixing a variable resistance sheet-like pressure detection element through a resilient member charging constantly between the seat fixing face and the floor face side fixing face in a central fixing hole. SOLUTION: A pressure detection element 1 comprises a pressure detection element body principally comprising particulate carbon sandwiched between a pair of electrodes and formed between a pair of thermally fused films by printing method. The pressure detection element body and the electrodes are formed into doughnut shape and provided with a central fixing hole. A constant load is applied constantly to the pressure detection element 1 from a normally compressed coil spring 22 and a measuring range is set around 0 point where the load is applied. A plurality of pressure detection elements 1 are fixed while clamping between a seat flame 14 and the brackets 15, 16 of left and right legs 11 secured to the floor surface H and pressure signals are converted through a weight conversion circuit into weight signals which are then added by an adder circuit in order to decide whether a person is seating in a seat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seating detection device for detecting whether or not a person is seated on a seat, and more particularly to determining whether or not to deploy an airbag for a passenger seat in a collision accident of a vehicle or the like. The present invention relates to a seating detection device used for a vehicle.

[0002]

2. Description of the Related Art A conventional occupant protection system will be described with reference to FIG. The microcomputer 51 includes the acceleration sensor 5
2 to determine whether or not it is necessary to deploy an airbag for the driver's seat and the passenger's seat based on the acceleration signal. The deployment of the airbag for the passenger seat and the squib 53,
This is performed by supplying an ignition current to 55. However, when the driver intentionally turns off the switch 54 attached to the instrument panel to the off state, the squib 55 for deploying the passenger airbag is provided by the microcomputer 51. No ignition current is supplied.

[0003]

In the above-described conventional occupant protection system, the driver determines whether or not to deploy the airbag for the passenger seat by the switch 54. The switch 54 had to be switched, which was bothersome and there was a risk of forgetting to switch. Therefore, recently, whether or not an occupant is seated in the passenger seat is detected using infrared rays, ultrasonic waves, microwaves, and the like,
It is considered that the switch is automatically switched by the detection signal.

[0004] However, in the method of detecting a seated person from the surface shape using infrared rays, the surface shape of a warm human body and the surface of a seat or the like warmed by sunlight are approximated. There was a problem that it was difficult to identify both. Also, in the method of detecting the distance from the instrument panel to the chest of a seated person using ultrasonic waves, for example, since the distance from the ultrasonic element is measured, the object on the seat is There is a problem that it is difficult to identify whether the seat is part of a seat. Furthermore, the method of detecting moisture in a human body using microwaves to determine whether the object is a human body or an object has a problem that it becomes an expensive device and is not practical.

The present invention has been made in view of the above problems, and has as its object to provide a practical seat detection device.

[0006]

According to a first aspect of the present invention, a plurality of pressure detecting elements provided on a mounting portion of a seat to a floor and detection from the pressure detecting elements are provided. Adding means for adding a signal; comparing the added output output from the adding means with a reference value; determining that the seat is seated on the seat when the added output exceeds the reference value; And a comparing means for outputting a pressure sensor, wherein the pressure detecting element is a sheet resistance pressure detecting element of a variable resistance type having a mounting hole in a central portion,
The seat is mounted between the seat mounting surface and the floor-side mounting surface via an elastic member via the mounting hole, and the pressure detecting element is constantly biased by the elastic member. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect, the sheet-like pressure detecting element is mounted on a resin plate from both upper and lower surfaces, and is provided with a mounting surface of the seat mounting portion and a mounting surface of the floor surface. And the holding surface is constantly urged by an elastic member.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The structure of the pressure detecting element 1 forming one configuration of the first embodiment according to the present invention will be described below with reference to FIG. That is, as a commercially available one, for example, a film-shaped pressure detecting element (trade name: Button Sensor, manufactured by Nitta Corporation) whose resistance value changes in inverse proportion to an externally applied load is used to detect this pressure. The element 1 has a structure in which a pressure sensing element main body 4 mainly composed of particulate carbon is sandwiched between a pair of electrodes between a pair of films to be thermally welded. It is formed by a printing technique.

On the other hand, in the pressure detecting element 1 according to the present invention, the pressure detecting element main body 4 and a pair of electrodes 5 and 6 are formed in a disk shape (doughnut shape) as shown in FIG. A mounting hole 7 is provided. Further, when an external load is applied to the pressure detecting element 1 from the surface direction, the resistance value (or output voltage) changes linearly partially with respect to the external load as shown in FIG. .

In this embodiment, a constant load M (see FIG. 2) is always applied to the pressure detecting element 1 by a coil spring which has already been compressed and contracted in a normal state. The load can be measured by setting A as the zero point on the measurement and setting the measurement range with the point A in between.

Next, the pressure detecting element 1 shown in FIG. 1 is connected to the frame 14 of the seat 10 and the brackets 15 (15a, 15a) of the pair of right and left legs 11, 11 fixed to the floor H.
b) and 16 (16a, 16b) will be described with reference to FIGS. 3 and 4.

First, the structure of the seat 10 will be described.
Reference numeral 0 denotes a backrest portion (not shown in FIG. 3), a seat cushion 12, a cushion cover 13 that covers the seat cushion 12, and a plate-shaped frame material that is bent and formed into a square shape. S-shaped springs (not shown) are mounted in the vertical and horizontal directions, the seat cushion 12 is placed on the upper side thereof, and box-shaped mounting portions 14a, 14b, 14c, 14 having upper end openings at respective four corners.
d is formed integrally with the frame 14 and the frame 1
4 comprises a pair of left and right legs 11, 11 having a rail mechanism for holding it movably in the front-rear direction. In addition, in the figure, the rail mechanism is not shown for simplification of the drawing.

The box-shaped mounting portions 14a, 14b, 1
4c, 14d, holes 1 corresponding to the mounting holes 7, 7, 7, 7, 7 provided in the pressure detecting element 1 are provided on the bottom walls.
4'a, 14'b, 14'c, 14'd are drilled.

The box-shaped mounting portions 14a, 14b, 1
The mounting surface between the lower surface of each bottom wall of 4c and 14d and the upper surface of a pair of brackets 15 and 16 provided on the pair of legs 11, 11 mounted on the floor,
The pressure detecting element 1 is held in a state of being sandwiched between resin plates 17 and 18 from above and below. The reason why the pressure detecting element 1 is sandwiched between the resin plates 17 and 18 is that an external force is uniformly applied to the entire surface of the pressure detecting element main body 4, and
Also, this is for protecting the pressure receiving surface of the pressure detecting element 1 from destruction.

Then, mounting holes 7, 7, 7, 7 and holes 14'a, 14'b, 1 provided in the pressure detecting element 1 are provided.
A bolt 20 penetrates through 4′c and 14′d, and a nut 21 is screwed into the bolt 20, whereby the pressure detecting element 1 is attached. In this state, a coil spring 22 is interposed between the inner bottom surfaces of the box-shaped mounting portions 14a, 14b, 14c, and 14d and the head 20a of the bolt 20 to apply pressure in the direction of the detection surface to the pressure detection element 1. Is equipped.

That is, by attaching the pressure detecting element 1 to the legs of the seat 10 as described above, when the human X is seated in a normal state as shown in FIG. 5, a downward force M is applied to all the legs. ' ₁ , M ” ₁ (arrow) works,
For example, as shown in FIG. 6, when the backrest 10 a of the seat 10 is switched to a reclining state in which the backrest 10 a is tilted backward and an external force is appropriately applied to the backrest, the weight of the human X is reduced to all the legs 11 of the seat 10. Without being applied, it acts only on the leg 11 located on the rear side, and a downward force M ″ ₂ (arrow) acts on the leg 11 located on the rear side. Leg 1 is located on the pressure sensing element
A force that raises 1, ie, an upward force M '
₂ (arrow) acts.

Next, the pressure signal obtained by the above configuration is subjected to signal processing by a signal processing circuit shown in FIG. 7 to determine whether or not a person is seated on the seat 10.
That is, 30 is a front right pressure sensor arranged at the front right corner of the four corners of the seat 10, 31 is a front left pressure sensor arranged at the front left corner of the seat 10, and 32 is arranged at the rear right corner of the seat 10. The rear right pressure sensor 33 is disposed at the rear left corner of the seat 10 and is the same as the pressure detecting element 1 shown in FIG. The pressure signals are connected to the first to fourth weight conversion circuits 34 to 37, respectively, and are converted from pressure signals to weight signals.

Reference numeral 38 denotes an addition circuit for adding the weight signals supplied from the first to fourth weight conversion circuits 34 to 37 and outputting the added signal. An occupant detection determination circuit 39 determines that a person is seated when the addition signal supplied from the addition circuit 38 exceeds a reference value, for example, 35 kg, and outputs an ON signal to the switch 54 in FIG. 9, for example. When the ON signal is being output, the ignition current is supplied to the squib 55 for the passenger seat as necessary. Reference numeral 40 denotes an alarm unit. When the magnitude of the pressure signal output from each of the front right pressure sensor 30, the front left pressure sensor 31, the rear right pressure sensor 32, and the rear left pressure sensor 33 is out of a predetermined range, a normal alarm is output. An alarm is generated to prompt a person seated as not being seated to be seated properly.

When the occupant sits on the seat 10 configured as described above, the weight of the occupant is increased by the front right pressure sensor 30,
It acts on each of the front left pressure sensor 31, the rear right pressure sensor 32, and the rear left pressure sensor 33 in a distributed manner, and is converted into a weight signal by each of the first to fourth weight conversion circuits 34 to 37 at the rear stage. The signal is supplied to the adding circuit 38, and after being added, is supplied to the occupant detection determining circuit 39. When it is determined that the value exceeds, for example, 35 kg, which is a reference value, the switch 54 is turned on. If the microcomputer 51 determines that a serious collision has occurred while the switch 54 is on, an ignition current is supplied to the squibs 53 and 55.

Embodiment 2 Next, a second embodiment will be described. In FIG. 8, the same or equivalent components as those already described with reference to FIG. 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. Will be described below. In FIG. 4, the box-shaped mounting portions 14a, 14b, 1
Mounting surfaces on the lower surface of the bottom wall of each of 4c and 14d;
The pressure detecting element 1 is sandwiched between resin plates 17 and 18 from above and below between mounting surfaces on the upper surfaces of a pair of brackets 15 and 16 provided on a pair of legs 11 and 11 mounted on the floor. In this embodiment, the resin plate is held in the state, and a rubber elastic body 61 is added to the resin plate directly on the upper surfaces of the pair of legs 11, 11 attached to the floor surface. The pressure detecting element 1 sandwiched between 17 and 18 is placed. A cylindrical elastic body 62 made of rubber is used instead of the coil spring 22 in FIG.

[0021]

As described above, according to the first aspect of the present invention, a sheet-shaped variable resistance type pressure detecting element having a mounting hole in the center is provided between the seat mounting portion and the floor surface. Since the body is attached via an elastic member, the weight of a seated person can be measured reliably, and the determination of the presence or absence of seating can be made reliably. In addition, an effect of being able to detect even when the user sits in an abnormal posture is exhibited.

According to the second aspect, since the pressure detecting element is held by the resin plate from both the upper and lower surfaces, the pressure detecting element can be protected even if the contact surface of the counterpart has some irregularities. You.

[Brief description of the drawings]

FIG. 1 is an exploded view of a pressure detecting element used in the present invention.

FIG. 2 is a characteristic diagram of the pressure detecting element shown in FIG. 1 and an explanatory diagram illustrating a state of use.

FIG. 3 is an assembly diagram showing a state where the pressure detection element shown in FIG. 1 is assembled to a seat.

FIG. 4 is an enlarged explanatory view of a main part for describing the present invention.

FIG. 5 is an explanatory diagram for explaining a force relationship applied to a pressure detecting element when a person is correctly seated on a seat.

FIG. 6 is an explanatory diagram illustrating a force relationship applied to a pressure detecting element when a person is seated with the seat in a reclining state.

FIG. 7 is a circuit block diagram illustrating an external signal processing circuit for an output signal from a pressure detecting element, particularly a signal processing state until the switch 54 of the occupant protection device of the occupant protection device is operated. .

FIG. 8 is an enlarged explanatory view of a main part for describing another embodiment.

FIG. 9 is a circuit block diagram of a conventional occupant protection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pressure detecting element 2, 3 Film 4 Pressure detecting element main body 6 Electrode 10 Seat 11 Leg part 12 Seat cushion 13 Cushion cover 14 Frame 15, 16 Bracket 14a, 14b, 14c, 14d Box-shaped mounting part 14'a, 14'b , 14'c, 14'd Hole 17, 18 Resin plate 20 Bolt 20a Head 21 Nut 22 Coil spring 30 Front right pressure sensor 31 Front left pressure sensor 32 Rear right pressure sensor 33 Rear left pressure sensor 34 to 37 First to first 4 weight conversion circuit 38 addition circuit 39 occupant detection determination circuit 40 alarm unit 51 microcomputer 52 acceleration sensor 53, 55 squib 54 switch 61, 62 cylindrical elastic body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masutoshi Aoyama 2-1910 Nisshincho, Omiya-shi, Saitama Prefecture Kansei Co., Ltd. (72) Inventor Katsushi 2-one 1910 Nisshincho, Omiya-shi, Saitama Kansainai F Term (reference) 2F051 AA01 AB06 AC01 AC07 3D054 AA03 AA14 DD28 EE10 EE11 EE14 EE31 EE57 FF09

Claims (2)

[Claims] 1. A plurality of pressure detecting elements provided on a mounting portion of a seat to a floor, an adding means for adding detection signals from these pressure detecting elements, and an addition output output from the adding means. Comparing the reference value with the reference value, when the addition output exceeds the reference value, determining that the user is seated on the seat, and comparing means for outputting a signal indicating the seating detection device. Is a variable resistance sheet-shaped pressure detecting element having a mounting hole at the center, and is mounted via an elastic member between the mounting surface of the seat and the mounting surface on the floor side via the mounting hole. A seating detecting device, wherein the pressure detecting element is constantly biased by an elastic member. 2. The sheet-like pressure detecting element is sandwiched between a mounting surface of a mounting portion of the seat and a mounting surface of the floor surface while being held by resin plates from both upper and lower surfaces, and the holding thereof. The seating detection device according to claim 1, wherein the surface is constantly urged by an elastic member.