JP3367430B2 - Occupant detection system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant detection system, and more particularly to a state in which an airbag of an airbag device can be deployed or cannot be deployed depending on the occupant's seating condition in the passenger seat of a vehicle equipped with the airbag device. The improvement of the occupant detection system that can be set to

[0002]

2. Description of the Related Art Generally, an airbag device is a device for alleviating an impact on an occupant in a vehicle collision.
It has become indispensable for the safety of automobiles, and it is recently installed not only in the driver's seat but also in the passenger seat.

This airbag device is provided with a safing sensor SS1, a squib SQ1, and a squib SQ1, as shown in FIG.
Switching element SW1 such as field effect transistor
Driver side squib circuit consisting of a series circuit, a safing sensor SS2, a squib SQ2, a switching element SW2 such as a field effect transistor, and a passenger side squib circuit, and an electronic acceleration sensor (collision detection sensor). The presence or absence of a collision is determined based on the output signals of the GS and the electronic acceleration sensor GS, and the switching elements SW1,
The control circuit CC has a function of supplying a signal to the gate of SW2.

According to this air bag device, when a car collides for some reason, the safing sensors SS1 and SS2 are closed by the switch contacts thereof reacting to a relatively small acceleration. The squib circuit on the passenger side becomes operable. Then, when the control circuit CC determines that the vehicle has surely collided based on the signal from the electronic acceleration sensor GS, the switching element S
A signal is supplied to the gates of W1 and SW2, and the switching elements SW1 and SW2 are turned on. As a result, a current flows through each squib circuit. As a result, the heat generated by the squibs SQ1 and SQ2 causes the airbags on the driver's seat side and the passenger's seat side to be deployed, and the occupant is protected from the impact due to the collision.

By the way, in this air bag system, the air bag is inflated when a vehicle crashes regardless of whether or not the occupant is seated in the seat. When the passenger is seated, the above-mentioned occupant protection effect can be expected in the event of a collision, but when the occupant is a child, the head position is low. Is concerned. Therefore, it may be desirable not to deploy the airbag even if the vehicle collides.

[0006]

Therefore, conventionally, in order to deal with such a problem, an airbag device as shown in FIG. 7, for example, has been proposed. This airbag device is provided with a sensor SD for detecting whether or not a passenger is seated in the passenger seat, and the control circuit CC determines the seating status of the passenger in the passenger seat based on the detection signal of the sensor SD. When an automobile collides, the airbag is set to either a deployable state or an undeployable state. In particular, this sensor SD uses a pressure-sensitive element whose resistance value changes according to the amount of pressure, and is arranged in an array between the sheet exterior material and the cushion material.

According to this proposal, the output signals from the plurality of pressure-sensitive elements (sensors SD) arranged in the sheet cause
It is possible to roughly judge whether the occupant seated in the seat is an adult or a child, and based on this result, the airbag is set to either a deployable state or an undeployable state, and It is possible to avoid an unforeseen situation at the time of the collision and to suppress the increase in system cost.

However, since the plurality of pressure sensitive elements are arranged in an array between the seat exterior material and the cushion material, when the occupant is seated in the seat, the occupant acts on the pressure sensitive element. The applied pressure (weight of the occupant) is relieved by the cushion material. For this reason, a pressure force that is originally smaller than the pressure force to be applied acts on the pressure-sensitive element, and a signal that does not correspond to the weight of the occupant is output from the pressure-sensitive element. This phenomenon varies depending on the location of the pressure-sensitive element, the seating posture of the occupant, etc., and tends to appear more prominently in areas where the cushioning effect is greater. Therefore, there is a problem that not only the detection accuracy regarding the occupant's seating situation is low, but also the variation is large,
It is a big obstacle to the spread.

Therefore, an object of the present invention is to accurately determine the seating condition of an occupant seated in a seat without being significantly affected by the seating posture of the occupant and based on the result of this judgment. An object is to provide an occupant detection system capable of appropriately controlling an airbag device.

[0010]

Follow SUMMARY OF THE INVENTION In order to achieve the object described above, the first invention of the present invention is to place the bag on the seat portion to the action of pressure in relation to the occupant of the seat A occupant detection system that detects a pressing force acting on the gas injected into the bag body by a pressure sensor, and detects the seating condition of the occupant based on an output signal from the pressure sensor ,
Install the control unit including the pressure sensor at or near the seat.
It is arranged beside, and the control unit is at least a bag body,
A pressure sensor that communicates with the bag and a port that supplies gas to the bag.
To the seat based on the pump and the output signal from the pressure sensor.
And a control circuit that determines the seating status of the passengers.
And are characterized. Further, a second aspect of the present invention is that a plurality of bags are arranged in a seat portion to which a pressing force is applied in relation to seating of an occupant, and the pressing force acting on the injecting gas of each bag is adjusted by detected by the pressure sensor in communication with the bag, a passenger detection system for detecting an occupant seating conditions on the basis of the output signals from the respective pressure sensors, before
A control unit including a bag and a pressure sensor can be attached to the seat part or
Is disposed in the vicinity of the control unit, and at least the control unit is
The bag, the pressure sensor communicating with the bag, and the gas are supplied to the bag.
Based on the pump to feed and the output signal from the pressure sensor
It consists of a control circuit that determines the seating status of the occupant.
It is characterized by being made.

A third aspect of the present invention is a bag body disposed in a seat portion where a pressure is applied in connection with seating of an occupant, and a bag body which is in communication with the bag body and acts on the gas injected into the bag body. An occupant detection system comprising: a pressure sensor for detecting pressure; and a control circuit for determining a seating condition of an occupant on a seat based on an output signal from the pressure sensor , wherein the bag body, the pressure
Install a control unit including a sensor in or near the seat
The control unit, at least the bag body, and the bag body.
Pressure sensor that communicates with the pump and a pump that supplies gas to the bag
And riding on the seat based on the output signal from the pressure sensor.
It is characterized by comprising a control circuit for judging the seating status of a member .

Further, a fourth aspect of the present invention is a bag body arranged in a seat portion where a pressing force is applied in relation to seating of an occupant, and a bag body which communicates with the bag body and acts on an injecting gas of the bag body. A pressure sensor that detects pressure, a control circuit that determines the seating condition of the occupant on the seat based on the output signal from the pressure sensor, and the airbag can be set to a predetermined operation mode based on the determination result of the control circuit An occupant detection system comprising an airbag device having a function , comprising:
Install a control unit including a sensor in or near the seat
The control unit, at least the bag body, and the bag body.
Pressure sensor that communicates with the pump and a pump that supplies gas to the bag
And riding on the seat based on the output signal from the pressure sensor.
It is characterized by comprising a control circuit for judging the seating status of a member .

A fifth aspect of the present invention is characterized in that a bag is arranged between the cushion material and the seat frame of the seat or inside the cushion material . Again
A sixth aspect of the invention is characterized in that a pump for supplying gas to the bag is connected via a valve .

In a seventh aspect of the present invention, in the control unit, a bag is connected to a pump via first and second valves, and a pressure sensor is branched and connected to the first valve. In the first operation mode, gas is supplied from the pump to the bag through the open first and second valves, and the second operation mode pressurizes the first valve. It is characterized in that the second valve is closed and the first valve is switched to open to the atmosphere in the third operation mode while switching and connecting to the sensor, and the gas in the bag is released. .

Further, in an eighth aspect of the present invention, the control circuit includes at least a memory section for storing threshold value data concerning a seating condition of an occupant and actual signal data fetched from a pressure sensor. Determining unit for determining whether the occupant is an adult or a child by comparing the threshold value data read from the memory unit and the storage unit that stores the signal with the actual signal data. And having.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a first embodiment of an occupant detection system according to the present invention will be described with reference to FIGS. The same parts as those of the conventional example shown in FIGS. 6 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 shows a passenger seat (or driver's seat) according to the present invention. The seat 1 is mainly composed of a seating portion 1a and a backrest portion 1b. The seating portion 1a is, for example, a seat frame 3 fixed to a base 2 which is slidable forward and backward, a cushion material 4 arranged on the seat frame 3, and an exterior covering the cushion material 4. The backrest portion 1b is formed by arranging a cushion material on the front side of the seat frame and covering the cushion material with an exterior material, for example.

A control unit 10 is arranged at or near the seat frame 3 of the seating portion 1a. The control unit 10 is a gas (for example, air) in which the weight (weight) of an occupant acting on a bag body 11 disposed between the seat frame 3 and the cushion material 4 is injected.
The seating condition of the occupant is determined based on the pressure applied to the passenger.

Specifically, the control unit 10 is connected to the bag body 11 arranged between the seat frame 3 and the cushion material 4 and the bag body 11 through a hose 15a. The first valve 12, the second valve 13 connected to the first valve 12 via the hose 15b, and the hose 15 to the second valve 13.
a pump 14 connected via c, a pressure sensor 16 connected to the first valve 12 via a hose 15d,
A / D for A / D converting the output signal from the pressure sensor 16
It is composed of a conversion circuit 17 and a control circuit 18 which receives a signal from the A / D conversion circuit 17 and judges the seating condition of the occupant. The first valve 12 has an exhaust hose 1
5e is branched and connected. Also, the first and second valves 12,
Opening / closing switching of 13 and control of driving / stopping of the pump 14 are mainly performed by signals from the control circuit 18.

In the control unit 10, a semiconductor pressure sensor shown in FIG. 3, for example, is applied to the pressure sensor 16. As shown in FIG. 3A, this pressure sensor 16 has a thin plate-shaped diaphragm portion D formed on a part of a silicon substrate S by etching, and four diaphragms (diffusion) are formed on the diaphragm portion D by a diffusion technique. Piezoresistor R is formed, and a supporting pedestal B having a large thickness is airtightly fixed to the silicon substrate S.
The space portion SP of the silicon substrate S is communicated with the bag body 11 via the hose 15d.

The four resistors R in the pressure sensor 16 are used in a bridge as shown in FIG. 3 (b). A DC voltage V is applied to this circuit, and an output signal Vout corresponding to the applied pressure (passenger weight) is taken out from the midpoint of the bridge. Here, assuming that the resistance value of the resistor R in the state where no pressure is applied is r and the variation of the resistance value in the state where pressure is applied is Δr, the output signal Vout is obtained by the following equation.

Vout = 2 (Δr / r) V This output signal Vout is output substantially in proportion to the weight of the occupant. For example, when the weight of the occupant is heavy, it becomes large, and when it is light, it becomes small. Therefore, by obtaining the correspondence relationship between the output signal Vout and the weight, the output signal Vout
It becomes possible to detect the weight from.

Further, the control circuit 1 of the above-mentioned control unit 10
8, an airbag device 20 via a communication means (not shown)
Are connected. For example, as shown in FIG. 4, the airbag device 20 includes a squib circuit on the driver's side including a safing sensor SS1, a squib SQ1, a switching element SW1 such as a field effect transistor and a squib circuit on the driver side. Whether there is a collision based on the output signals of the squib circuit on the passenger side, which is composed of SS2, squib SQ2, switching element SW2 such as a field effect transistor, an electronic acceleration sensor (collision detection sensor) GS, and an electronic acceleration sensor GS And a control circuit CC having a function of supplying a signal to the gates of the switching elements SW1 and SW2.

The occupant detection system configured as described above operates as follows. First, when the ignition switch is turned on, the first operation mode is set by the signal from the control circuit 18, and the first and second valves 12 and 13 are controlled to the open state, and at the same time, the pump 14 is driven. ,
Gas (air) is supplied from the pump 14 to the bag body 11 through the hose 15c, the second valve 13, the hose 15b, the first valve 12 and the hose 15a for a predetermined time. When the supply of air to the bag 11 is completed, a second operation mode is set by the signal from the control circuit 18, and the hose 15d is communicated with the bag 11 by the switching operation of the first valve 12. At the same time, the second valve 13 is closed and the pump 14 is stopped. As a result, when the occupant is seated in the seat 1, the weight of the occupant acts on the bag body 11 as a pressing force, and at the same time, the same pressure acts on the air injected inside. This pressure acts on the space portion SP of the pressure sensor 16 via the hoses 15a and 15d, and the diaphragm portion D is pressed. The stress applied to the diaphragm portion D changes the resistance value of each resistor R by Δr, and the pressure sensor 16 outputs an output signal of 2 (Δr / r) · V 2. Each of these signals is A / D converted by the A / D conversion circuit 17 and taken into the storage section of the control circuit 18.

In the control circuit 18, a threshold value relating to the seating status of the occupant seated in the seat 1 (whether seated or not, whether adult or child, etc.) is stored in advance in the external memory section (memory section). Remembered in. For example, the threshold value for identification is, for example, when the weight of the occupant is 30 kg or less, the signal data corresponding to the weight detected by the pressure sensor 16 is "the occupant's weight is 30 kg or less. 1
Threshold value TH1 "of the occupant, and when the weight of the occupant exceeds 50 kg, the signal data corresponding to the weight detected by the pressure sensor 16 is" the weight of the occupant is 50 ".
It is set as a second threshold value TH2 "for judging that it has become equal to or higher than Kg. Therefore, in the control circuit 18, the threshold data relating to the occupant identification stored in advance is stored.
The weight of the occupant seated in the seat 1 is compared with the signal data relating to the weight corresponding to the pressure of the air actually detected by the pressure sensor 16 in the determination unit. Is 30 Kg or less, or 50 Kg or more, or 30 to
It is judged whether it is within 50 kg. It should be noted that the number of thresholds may be one and the upper and lower sides of the threshold may be used for identification.

Therefore, if the signal data fetched by the control circuit 18 is smaller than the first threshold value TH1, the weight of the occupant is 30 kg or less, and it is determined that the child is a child. Therefore, the airbag shown in FIG. The device 20 is set by the transmission signal from the control circuit 18 so that the airbag cannot be deployed. On the contrary, if the actual signal data is larger than the second threshold value TH2, the weight of the occupant is 50 kg or more, and it is determined that the passenger is an adult.
The airbag is set so that it can be deployed by a transmission signal from the airbag. That is, the transmission signal from the control circuit 18 is input to the control circuit CC of the airbag device 20, and in the former case, it is set so as not to supply the gate signal to the switching element SW2 on the passenger side when the vehicle collides. However, a gate signal is supplied to the switching element SW1 on the driver side. In the latter case, the switching element S
It is set so that the gate signal is supplied to W1 and SW2. The first threshold value TH1 and the second threshold value TH
The area between 2 and 2 is a gray area, and when actual signal data exists in this area, the airbag is set to either deployable or undeployable depending on the situation.

In the second operation mode, the pressure sensor 1
When the signal data from 6 is taken into the control circuit 18 and the arithmetic processing is completed, the signal from the control circuit 18 causes the third operation mode, and the first valve 12 is switched to the hose 15e. Are connected so as to communicate with the bag body 11. As a result, the air injected into the bag body 11 is discharged to the atmosphere through the hose 15a, the first valve 12, and the hose 15e, and the series of operations is completed. This operation is recommended to be performed when the ignition switch is turned on, but can be repeated at regular time intervals.

According to this embodiment, since the bag body 11 is arranged between the seat frame 3 and the cushion member 4 of the seat 1, when the occupant is seated in the seating portion 1a. , As a result that the weight of the occupant always acts on the bag body 11 as a pressing force,
Similar pressure acts on the air injected into the bag 11. Therefore, by detecting the applied pressure by the pressure sensor 16, the weight of the occupant having a corresponding relationship with the applied pressure can be easily detected, and the occupant can be accurately identified as an adult or a child.

Particularly, when the seating condition of the occupant is detected, the air is supplied from the pump 14 to the bag body 11 for a certain time each time, and the air in the bag body 11 is discharged after the detection operation is completed. Moreover, the detection conditions can be made constant, and highly reliable occupant detection with little variation can be expected.

Since the control unit 10 including the bag body 11 and the pressure sensor 16 is arranged at or near the sheet portion, the path length from the bag body 11 to the pressure sensor 16 is set to be short. it can. Therefore, not only the control unit 10 can be configured compactly, but also the pressure corresponding to the weight by the pressure sensor 16 can be accurately detected.

Furthermore, since the operation of the airbag device 20 is controlled according to the result of the judgment regarding the seating condition of the occupant based on the output signal from the pressure sensor 16, for example, the seat 1 is seated by a child. If it is determined that the airbag is present, the deployment of the airbag can be stopped. Therefore, it is possible to perform desirable control according to the seating condition of the occupant.

FIG. 5 shows a second embodiment of the occupant detection system according to the present invention, which is basically the same as the first embodiment shown in FIGS. The difference is that in the control unit 10A, the bag body 11 and the pump 14 are connected via the hose 15a, the second valve 13, and the hose 15c, and the pressure sensor 16 is connected to the hose 15d, 15a. That is, it is directly connected to the bag body 11 via. The second valve 13 and the pump 14 are controlled by signals from the control circuit 18.

The control unit 10A operates as follows. First, in a state where no occupant is seated in the seat, air is supplied from the pump 14 to the bag body 11 so that the internal pressure of the bag body 11 becomes substantially constant, and after reaching a constant pressure, the second Valve 13 is closed and pump 14 is stopped. The pressure is detected by the pressure sensor 16. Next, when the occupant is seated in the seat, a pressing force acts on the bag body 11 according to the weight of the occupant, and a similar pressing force acts on the air inside. This pressure is hose 15
pressure sensor 1 connected in communication with a and 15d
Detected by 6. Hereinafter, the same processing as in the first embodiment is performed.

According to this embodiment, since air is constantly infused into the bag body 11, it is possible to immediately detect whether the occupant is an adult or a child while the occupant is seated in the seat. . Therefore, the occupant can be frequently detected while the vehicle is traveling, and the occupant can be detected with finer grain.

The present invention is not limited to the above embodiment, and the number of bags installed can be increased from one to a plurality, thereby increasing the amount of information regarding seating of passengers. It is possible to detect passengers with higher accuracy. Further, it is recommended that the bag is installed between the seat frame and the cushion material, but it may be anywhere as long as it is a seat portion where a pressing force acts on the bag in relation to seating of an occupant. .
A semiconductor pressure sensor is recommended as the pressure sensor, but an appropriate one such as a normal diaphragm to which a strain gauge is fixed can be applied. Further, based on the determination result of the control circuit, it is possible to control the seat belt wearing state, a warning light, etc., instead of the airbag device.

[0035]

As described above, according to the present invention, the occupant is seated in the seat because the bag is arranged in the seat portion where the pressing force acts when the occupant is seated. In this case, as a result of the weight of the occupant always acting as a pressing force on the bag body, a similar pressing force also acts on the air inside the bag body. Therefore, by detecting this pressing force with the pressure sensor, the weight of the occupant having a corresponding relationship with the pressing force can be easily detected, and it is possible to accurately judge the seating situation such as whether the occupant is an adult or a child. it can.

In particular, when the seating condition of the occupant is detected, each time the air is supplied from the pump to the bag for a certain time and the air in the bag is discharged after the detection operation is completed. The detection conditions can be made constant, and highly reliable occupant detection with little variation can be expected.

Further, if the control unit including the bag and the pressure sensor is arranged at or near the sheet portion, the path length from the bag to the pressure sensor can be set short. Therefore, not only the control unit can be made compact, but also the pressure corresponding to the body weight can be accurately detected by the pressure sensor.

Furthermore, if the operation of the airbag device is controlled in accordance with the result of the judgment regarding the seating condition of the occupant based on the output signal from the pressure sensor, for example, it is possible that the seat is occupied by a child. If determined, the deployment of the airbag can be stopped. Therefore, it is possible to perform desirable control according to the seating condition of the occupant.

[Brief description of drawings]

FIG. 1 is a side sectional view of an essential part showing a first embodiment of an occupant detection system according to the present invention.

FIG. 2 is a circuit block diagram of the control unit shown in FIG.

3A and 3B are explanatory views of the pressure sensor shown in FIG. 2, in which FIG. 3A is a side sectional view and FIG. 3B is an electric circuit diagram.

FIG. 4 is a circuit block diagram of the airbag device shown in FIG.

FIG. 5 is a circuit block diagram showing a second embodiment of an occupant detection system according to the present invention.

FIG. 6 is a circuit block diagram of a conventional airbag device.

FIG. 7 is a circuit block diagram of an improved airbag device of a conventional example.

[Explanation of symbols]

1 sheet 1a Seating section 1b Backrest 3 sheet frames 4 cushion material 5 Exterior materials 10,10A control unit 11 bags 12 First valve 13 Second valve 14 pumps 15a to 15e hoses 16 Pressure sensor 17 A / D conversion circuit 18 Control circuit 20 Airbag device SS1, SS2 safing sensor SQ1, SQ2 squib SW1, SW2 switching element CC control circuit GS Electronic acceleration sensor

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-10-29495 (JP, A) JP-A-10-236275 (JP, A) JP-A-10-236276 (JP, A) JP-A-10- 236274 (JP, A) JP-A-11-148855 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60R 21/16-21/32 B60N 2/42 G01V 9/00

Claims (8)

(57) [Claims] 1. A bag body is arranged in a seat portion where a pressure is applied in relation to seating of an occupant, and a pressure sensor which detects a pressure applied to an injecting gas in the bag is used as an output signal from the pressure sensor. an occupant detection system for detecting an occupant seating conditions based, seat part control unit including the bag, the pressure sensor
Or place it near it and reduce the number of control units.
The bag, the pressure sensor communicating with the bag, and the gas in the bag.
Based on the output signal from the pump and the pressure sensor
A control circuit that determines the seating status of the occupant
An occupant detection system characterized by being configured from the above . 2. A plurality of bags are arranged in a seat portion to which a pressing force is applied in relation to seating of an occupant, and the pressing force acting on the injecting gas of each bag is communicated with each bag body. detected by a sensor, a passenger detection <br/> known system for detecting an occupant seating conditions on the basis of the output signals from the respective pressure sensors, seat part control unit including the bag, the pressure sensor
Or place it near it and reduce the number of control units.
The bag, the pressure sensor communicating with the bag, and the gas in the bag.
Based on the output signal from the pump and the pressure sensor
A control circuit that determines the seating status of the occupant
An occupant detection system characterized by being configured from the above . 3. A bag body arranged in a seat portion where a pressure is applied in relation to seating of an occupant, a pressure sensor which communicates with the bag body and detects a pressure applied to an injecting gas of the bag body, and a pressure. An occupant detection system including a control circuit that determines a seating condition of an occupant based on an output signal from a sensor
And the control unit including the bag body and the pressure sensor is a seat portion.
Or place it near it and reduce the number of control units.
The bag, the pressure sensor communicating with the bag, and the gas in the bag.
Based on the output signal from the pump and the pressure sensor
A control circuit that determines the seating status of the occupant
An occupant detection system characterized by being configured from the above . 4. A bag disposed in a seat portion where a pressure is applied in relation to seating of an occupant, a pressure sensor which communicates with the bag and detects a pressure applied to the gas injected into the bag, and a pressure. A control circuit that determines the seating condition of the occupant on the seat based on the output signal from the sensor, and an airbag device that has a function of setting the airbag to a predetermined operation mode based on the determination result of the control circuit are provided. in the occupant detection system
There is a control unit including the bag and pressure sensor in the seat part.
Or place it near it and reduce the number of control units.
The bag, the pressure sensor communicating with the bag, and the gas in the bag.
Based on the output signal from the pump and the pressure sensor
A control circuit that determines the seating status of the occupant
An occupant detection system characterized by being configured from the above . 5. The occupant detection system according to claim 1, wherein a bag is arranged between the cushion material of the seat and the seat frame or inside the cushion material. 6. The occupant detection system according to claim 1, wherein a pump that supplies gas to the bag body is connected via a valve. 7. In the control unit, a pump is connected to the bag through first and second valves, and a pressure sensor is branched and connected to the first valve, and the first operation mode is set. Gas is supplied from the pump to the bag through the open first and second valves, and the first valve is switched and connected to the pressure sensor in the second operation mode and the second valve is closed. And then the third
2. The gas in the bag body is released by switching the first valve to open to the atmosphere in the operation mode of 1.
The occupant detection system according to any one of to 4 . 8. The control circuit includes at least a memory unit for storing threshold value data regarding a seating condition of an occupant.
Whether the occupant is an adult or a child by comparing the storage unit that stores the actual signal data captured from the pressure sensor with the threshold value data read from the memory unit and the storage unit and the actual signal data. The occupant detection system according to claim 3 or 4, further comprising a determination unit that determines