JPH0778539B2 - Occupant detection device - Google Patents

Description

The present invention relates to a device for detecting whether or not a moving body such as a vehicle is seated on an occupant seat.

[Conventional technology]

For example, in some types of vehicles, side windows (driver seat door window, passenger seat door window, driver seat rear seat door window and passenger seat rear seat door window), sunroof (roof panel), etc. An occupant detection device for detecting whether or not an occupant is present in the occupant seat is provided for the purpose of car audio control or the like. In this case, when it detects that there is no occupant in all occupant seats, it closes the open side windows and / or sunroof, or adjusts the car audio output balance to suit the occupant position (the seat position where the passenger is seated). Are in control.

An occupant detection device that has been commonly used in vehicles of this type has been known as a seat switch. This seating switch is a switch embedded in the seat (chair) of each seat, and has a configuration in which the contact point is closed when the passenger is seated.

FIG. 8a is a perspective view showing a cross section of a passenger seat of a vehicle and its periphery. Although the structure of the vehicle seat will be described later, 30 is a seat cushion trim cover, 31 is a seat cushion pad, 32 is a seat cushion pad support, 33 is a seat cushion spring, and 34 is a seat cushion frame.

The seating switch 100 is embedded in the seat cushion pad 31. The area around the seating switch 100 is shown in detail in FIG. 8b. Referring to FIG. 8b, the seat switch 100
Is mainly composed of the movable contact 101 and the fixed contact 102,
The fixed contact 102 is fixed to the seat cushion pad support 32. The seat cushion pad 31 and the seat cushion pad support 32 are both flexible and bend together when the occupant is seated.
Since it is made of a more flexible material (for example, urethane foam), the seat cushion pad support 31 is integrated with the seat cushion trim cover 30 as shown by the broken line in FIG. 8b. so)
It flexes relatively. As a result, the movable contact 101 rotates about the movable shaft, and the switch contact with the fixed contact 102 is closed (switch on). The seating switch 100 (movable contact 101 and fixed contact 102) is connected to an electric circuit (not shown), and the seating switch 100 is turned on / off in the circuit.
When it is off, it is detected whether or not the occupant is seated.

[Problems to be Solved by the Invention]

By the way, the seating switch 100 is mechanically opened / closed by the bending of the seat cushion pad 31 due to the seating of the occupant, and thus is vulnerable to a shock. Prone to obstacles. Further, since it is a contact switch, the life of the contact portion is short, and the switch is turned on even when a luggage other than a person is put on, so that the detection reliability is low.

In view of the drawbacks of the conventional occupant detection device described above, it is an object of the present invention to provide a simple and highly reliable occupant detection device for detecting the seating of an occupant on an occupant seat.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, a flexible seat cushion conductive layer provided inside a seat cushion surface layer of a vehicle seat and having a wide surface covering substantially the entire surface on which an occupant sits; Of the seat back surface layer, the flexible seat back conductive layer having a surface along the surface; a seat cushion conductive layer and a seat back conductive layer with at least a portion of an occupant seated on the vehicle seat interposed therebetween. Detecting means for detecting a change in capacitance between the on-vehicle conductor facing at least one surface of the vehicle and the seat cushion conductive layer and the seat back conductive layer; and the detecting means increasing the capacitance. Detection processing means for generating an electric signal indicating that the vehicle seat is seated.

[Action]

According to this, the flexible conductive layers of the seat cushion and the seat back and the on-vehicle conductor are opposed to each other with at least a part of the occupant seated on the seat interposed therebetween, and the capacitor (hereinafter, this configuration is used for occupant detection). Capacitor), the capacitance of which changes depending on the presence or absence of a human body (occupant) having a high dielectric constant (about 80). Therefore, by detecting the change in the capacitance, the presence / absence of seating on the occupant seat can be detected in a non-contact manner.

Since the flexible conductive layer provided in the seat cushion of the vehicle seat has a wide surface, seating of a small passenger such as an infant or a child can be reliably detected. Since the seat back of the car seat is also provided with a flexible conductive layer, the flexible conductive layer is distributed so as to cover the rear half of the upper half of the occupant, so that the occupant detection range is wide and infants, children, etc. The occupant with a small body has high reliability of seating detection, and the possibility of detecting no seating due to displacement of the body of the occupant on the vehicle seat or change in posture is reduced, and seating detection reliability is extremely high.

In addition, since the conductive layer is flexible and is inside the surface layer of the sheet, it is not damaged by impact, vibration, etc., and is not damaged or worn by collision or rubbing of objects, and is excellent in durability and reliability. .

By equipping each of the vehicle seats with the occupant detection device of the present invention, it is possible to know whether or not each of the vehicle seats has a seat, and the distribution of the seated persons. It can be controlled in a manner suitable for the user. In addition, automatic control for security can be performed, such as automatically closing the vehicle window when all seats are not seated.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Embodiment) FIG. 1a shows an embodiment of the present invention. Referring to FIG. 1a, the seat cushion 20 of the vehicle seat ST _FR is fitted with a roof
Equipped with detection electrodes EL _FR facing each other across a space above ROOF and FR seats (front right seat: driver seat) [space where driver (passenger) MAN sits].

The roof ROOF of the present embodiment is made of metal (that is, a conductor), and the metal such as pillars (not shown), doors (DOR _FR and other doors), floor Flor, etc. of the vehicle engaged with the roof ROOF. It is electrically connected to the manufacturing members (hereinafter, these members including the roof ROOF are referred to as the body). Therefore, a detection electrode EL _FR, by a body, occupant detection capacitor (C
_{When FR} ) is constituted, the electric force lines coming out (or coming in) from the detection electrode EL _FR are very complicated toward (or come out from) various parts of the body, but in this embodiment, for convenience of explanation, Assuming that the detection electrode EL _FR and the roof ROOF form the occupant detection capacitor C _FR , electric lines of force extending straight from the detection electrode EL _FR to the roof ROOF are shown by broken lines in FIG. 1a.

DET _FR is a detection circuit for detecting the capacitance change of the occupant detection capacitor C _FR composed of the detection electrode EL _FR and the roof ROOF, and AMP is a direct current for amplifying the output of the detection circuit DET _FR. The amplifier circuit, BIN is a binarization circuit that binarizes the output of the DC amplifier circuit AMP. In addition, in FIG. 1a, the resistor is represented by a rectangle.

First, the configuration will be described with reference to the partially crushed perspective view of the sheet ST _FR shown in FIG. 2a. The seat ST _FR is mainly composed of a seat cushion 20, a seat back 22, and a headrest 24, and both sides of the seat cushion 20 support a occupant's waist 21, a seat back 2 and a seat back 2.
Both sides of 2 are side supports 23 for holding the upper body of the occupant.

Seat cushion 20 is seat cushion frame 34
The seat cushion spring 33 is set on the seat cushion pad 33, the seat cushion pad 31 is placed on the seat cushion spring support 32, and the seat cushion trim cover 30 is placed over the seat cushion pad 31. In the seat back 22, a seat back spring 43 is set on a seat back frame 44, a seat back pad 41 is placed on the seat back pad support 42 via the seat back pad support 42, and a seat back trim cover 40 is further laid up. It has become.

The structure of the seat cushion trim cover 30 is shown in FIG. 2b. Referring to FIG. 2b, the seat cushion trim cover 30 includes a skin 50, a wadding 51, and a wadding cover.
52 is formed into a single sheet. Particularly, in the trim cover 30 of the portion of the seat cushion 20 excluding the side support 21, as shown by hatching in FIG. 2b, the wadding 51 has a conductive surface on the contact surface with the back surface of the outer skin 50. The detection electrode EL _FR is formed by sputtering a conductive paint. That is, the seat ST _FR in this embodiment.
A schematic side view is shown in Fig. 3a and a schematic front view is shown in Fig. 3b.The sensing electrode EL _FR is installed near the surface of the seat cushion 20 and over a wide range of almost the entire area on which the occupant sits. To be done.

With reference to FIG. 1b, the detection operation of the capacitance change of the occupant detection capacitor C _FR by the detection circuit DET _FR will be described. In Fig. 1b, the occupant detection capacitor C _FR is
Equivalent capacitance variable capacitor is shown (capacity changes depending on whether or not passenger MAN is used).

OSC is an oscillator that outputs a positive / negative symmetrical sine wave AC voltage (triangular wave, rectangular wave, etc., if positive / negative symmetrical), Cs
Is a reference capacitor, Co is a storage capacitor, LPF is a resistor R
And a low-pass filter consisting of a capacitor C, D ₁ ,
D ₂ , D ₃ and D ₄ are diodes. In this embodiment, the capacity of the capacitor Cs is set to be equal to the capacity of the passenger detection capacitor C _FR when the passenger MAN is not seated in the FR seat.

Each capacitor C _FR , Co and Cs repeats charging and discharging for every positive and negative cycle of the sine wave AC voltage output from the oscillator OSC. Here, focusing on the storage capacitor Co, the currents passing through the capacitor Co are i ₁ and i ₂ in FIG. 1b. The current i ₁ is the current that charges the capacitor C _FR through the diode D ₂ during the negative half cycle of the sine wave AC voltage output by the oscillator OSC, and the current i ₂ is the sine wave AC voltage output by the oscillator OSC. The current that charges capacitor Cs through diode D ₄ during the positive half cycle.

In this case, if C _FR = Cs, then i ₁ = i ₂ , and since the directions are opposite, the charging / discharging voltage of Co is canceled and the terminal voltage does not appear, but if C _FR ≠ Cs, then i ₁ ≠ It becomes i ₂ , and Co is charged in one direction, and the inter-terminal voltage appears.

However, storage capacitor Co diode D ₁ and
Since it is short-circuited by D ₂ or by the diodes D ₄ and D ₃ , the voltage between terminals of Co theoretically does not appear. However, Fig. 1c shows a graph of the relationship between the forward voltage V _D of the diode and the forward current I _D. As can be seen by referring to this graph, the forward critical voltage V _D mi
The current I _D does not flow below n. Accordingly, in the detection circuit DET _FR of this embodiment, the storage capacitor caused by C _FR ≠ Cs
The voltage between the terminals of Co is set to be equal to or lower than the forward critical voltage V _D min. The voltage across the terminals of the capacitor Co is output as a DC voltage V _out via the low pass filter LPF.

In other words, in the detection circuit DET _FR , the passenger MAN is seated in the FR seat, the electrostatic capacitance of the passenger detection capacitor C _FR increases, and Cs
When <C _FR , positive DC voltage V _out is output.

In the DC amplifier circuit AMP shown in Fig. 1a, the detection circuit DET _FR output
V _out is amplified, and the binarization circuit BIN compares the output of the amplification circuit AMP with a predetermined threshold value and outputs a binary value. This predetermined threshold value is the AMP output value due to the electrostatic capacitance of the capacitor C _{FR in} the steady state (when the passenger MAN is not in the FR seat) (exactly Cs = C _FR is difficult to set, The value is set to a value slightly higher than that (slightly output) (to prevent hunting), and "0 (L level)" means "occupant present".
A signal indicating "no occupant" is output at "1 (H level)".

FIG. 5a shows the configuration of a power window control system of a vehicle including an occupant detection device. Referring to FIG. 5a, this system mainly includes a microcomputer (MPU) 7, and is composed of an input switch circuit 8, a drive circuit 9, a power supply circuit 10, a current detection circuit 11, an occupant detection device 12, and the like.
In addition, in the following, what is attached to the FR seat is "FR-
− ”Or“ −− _FR ", front left seat (passenger seat) FL
Seats, those associated with FL seats are "FL--" or "-
- _FL ", rear right seat (driver back seat) of the RR seat, those associated with the RR seat" RR-- "or" - _RR ", the rear left seat (passenger rear seat) RL seats, RL What is attached to the seat is "RL
It is expressed as _--- "or" _--RL ".

Input ports R0~R7 and output ports P _0, P ₁ of MPU7 is connected to the input switch circuit 8. Details of the input switch circuit 8 are shown in FIG. 5b. This will be described with reference to FIG. 5b.

This input switch circuit 8 has FR window, FL window, RR window and RL window.
Window up / down switches & auto up / down switches, FR window glass, FL window glass, RR window glass and RL window glass position detection limit switches MS _FR , MS _FL
(See Fig. 6c), MS _RR , MS _RL ; FR door, FL door, RR door and door courtesy switch OC _FR , OC for detecting RL door open / close
_FL , OC _RR , OC _RL ; FR door, FL door, RR door and RL door door lock / unlock detection switch DL _FR , DL _FL , DL
_RR , DL _RL ; and an IG key switch for detecting the presence / absence of an ignition key provided at an ignition key insertion port (not shown) are connected. In FIG. 5b, the limit switch MSij, the door courtesy switch OCij, and the door lock / unlock switch DLij are shown, but the subscript i is _F or
_The suffix _R indicates _R or _L.

The input switch circuit IC2 is a microcomputer (MP
U) is a decoder connected to the output ports P ₀ and P ₁ of 7 and selectively sets one of the output terminals A to D to 0 (L level) according to the signals of P ₀ and P ₁ and Is set to 1 (H level). This input / output relationship is shown in Table 1 below.

The outputs of the output terminals A to _D are inverted by the inverters INV _{A to} INV _D. When the output terminals of these inverters are at H level (0) and the fixed contact of the switch connected to them is connected to the movable contact to become H level (1), the level at that connection point becomes H level (1). When the fixed contact of the switch becomes L level (0), the level of the connection point becomes H level (0). Further, when the output terminals of these inverters are at L level (0), the diode is conductive even if the fixed contact of the switch connected to it is connected to the movable contact and becomes at H level (1), so the connection is made. The point level remains L level (0). Ie MP
U7 is a 29 different switch operation of the input switch circuit switches the level of the output ports P ₀ and P _1, read from seven input ports R ₀ to R _7.

For example, the input switch circuit 8 is connected to the same input port R _0.
The FR window up / down switch UP contact (fixed side: same below), RR window up / down switch UP contact, IG key switch contact, and RL door courtesy switch OC _RL contact are connected, but output If both the ports P ₀ and P ₁ are set to 0, only the output of the inverter INV _A becomes H level (1), so that FR window up operation, that is, UP contact ON / OFF can be read.

Referring again to FIG. 5a.

The relay driver of the drive circuit 9 is connected to the output ports O _{0 to} O ₈ of the microcomputer (MPU) 7. The relay driver is composed of an inverter and a switching transistor, etc., and when the output port becomes L level (0), it is inverted by the inverter to make the switching transistor conductive and energize the relays RY _{1 to} RY ₈ connected thereto. .

When the output port O ₀ becomes L level (0) and the relay RY1 is energized, the relay contact ry1 is closed and connected to the + B power supply, and the current in the arrow DOWN direction is applied to the FR window lifting motor M _FR. Flow, energizing the motor M _FR in the reverse direction. Output port O ₁ is L
It becomes level (0), the relay RY2 is energized, the relay contacts ry2 is connected to the closed + B power, the arrow UP direction current flows through the motor M _FR for FR window lifter, the motor M _FR Energize forward.

Similarly, the relay RY3 or RY4 is selectively energized to energize the motor M _FL for raising and lowering the FL window in the forward and reverse directions; relay RY5 or RY6
To energize the motor _RR for raising and lowering the RR window forward and reverse; energize the relay RY7 or RY8 to energize the motor M _RL for raising and lowering the window _RL . is doing.

Here, the window lifting mechanism will be described with reference to FIGS. 6a, 6b, and 6c. Fig. 6a shows the window glass (FL
An electric mechanism that drives the window 2 up and down is shown. Referring to this figure, the pins at one end of the link arms 3 ₁ and 3 ₂ are connected to the upper and lower guide rails fixed to the window glass 2, respectively. by which, the lifting arm which engages the other end of the link arm 3 _2, sector gear 4 coupled to drive lifting it. The sector gear 4 meshes with the wheel of the worm wheel assembly 5, and the worm meshing with the wheel is connected to the motor.
The rotation axis of M _FL is connected. Sector gear 4 and worm
The combination with the wheel assembly 5 is shown in FIG. 6b.

When the motor M _FL rotates forward, this rotation causes the sector gear 4 to rotate clockwise in FIG. 6a via the worm wheel assembly 5 and push the glass 2 upward (window closing). motor
When the M _FL rotates in the reverse direction, this rotation causes the sector gear 4 to rotate counterclockwise in FIG. 6a via the worm wheel assembly 5 to lower the glass 2 (open the window).

FIG. 6c shows a sectional view taken along the line VIC-VIC of FIG. 6a. As shown in the figure, a limit switch MS _FL for position detection is provided in the hollow portion above the door frame. Switch MS _FL
The movable contact of the door frame is weather strip 6
When the window glass 2 reaches the upper limit position, the movable contact piece is pushed by the bending of the weather strip 6 and the switch MS _FL is turned on. Therefore, when the window glass 2 is below the upper limit position, the switch MS _FL is off.

Although only the window raising / lowering mechanism of the FL door 1 is illustrated here, the other doors (FR, RR, RL doors) have the same structure.

Referring again to FIG. 5a. A current detection circuit is connected to the power supply line of each window lifting motor. As you know,
Since the motor current is proportional to the motor load, the motor current of each lifting / lowering motor (M _FR , M _FL , M _RR , M _RL ) is detected as the terminal voltage of the resistor r. That is,
Since each motor has an excessive load at the lower limit position of the window glass to be driven, the full opening of the window is detected by this.

The occupant detection device 12 detects presence / absence of occupants in FR seats, FL seats, RR seats, and RL seats. As shown in FIG. 5c, this device 12 is composed of four blocks 12 _FR , 12 _FL , 12 _RR and 12 _RL having the same configuration, with one oscillator OSC being common. The configuration and operation of each block are exactly the same as those shown in FIG. 1a described above, and therefore the description thereof is omitted here (in FIG. 5a, the resistors are shown by rectangles).

Electrodes EL _FR , EL _FL , on the seat cushions (not shown) of FR seats, FL seats, RR seats, and RL seats where passengers sit
Equipped with EL _RR and EL _RL, the detection terminals of the corresponding blocks are connected.

For each seat (FR seats, FL seats, RR seats, RL seats), signals for presence or absence of passengers (with passengers: 0, without passengers: 1) are input ports R8, R of MPU7.
9, given to R10 and R11.

The MPU 7 controls the FR window, FL window, RR window, and RL window as roughly described below. That is, when each window up switch is operated, that window is controlled to be closed for the time that the switch is on, and when each window down switch is operated, that window is turned on. The corresponding window is controlled to open, and when each window auto up switch is operated, the corresponding window is fully closed.When each window auto down switch is operated, the corresponding window is fully opened to control the occupant. When no boarding and a predetermined state of the vehicle (end-of-use state) are detected, the open window is fully closed (forgotten closing prevention control). FIG. 7 is a flow chart showing the operation of the MPU 7 mainly for the forgetting to close control. This will be described with reference to FIG. In the following description, "S--"
Indicates a step number (S is omitted in the flowchart).

When connected to the vehicle battery and turned on, the registers, flags, memory, etc. are initialized in S1.

At S2, each switch operation is read as described above.

If the IG key switch is turned on in S3, the process proceeds to S7 and S8, and the opening / closing control of each window is performed according to the switch operation. At this point, when the FR window is fully closed, set the "FR fully closed" flag to FL
Set the "FL fully closed" flag when the window is fully closed, the "RR fully closed" flag when the RR window is fully closed, and the "RL fully closed" flag when the RL window is fully closed. .

The driver and his passengers remove the ignition key (IG key switch off), lock all doors (all door lock switch on), close all doors (all door courtesy switch on), and finish using the vehicle. Get away from. Therefore, proceed from S3 → S4 → S5 → S6, and enter port R8
~ If R11 is 1 (no occupants in all seats), proceed to S9.

In S9, the presence or absence of the "FR fully closed" flag is checked. This "FR
If there is a "fully closed" flag, the FR window is already in a fully closed state, so proceed to S13. If there is no "FR fully closed" flag, F
Since the R window is not fully closed yet, switch on S10.
Check the status of MS _FR . Since the FR window is not fully closed, the switch MS _FR is off, and the output port O _{0 is set} to 1 at S11.
(H), the output port O ₁ is set to 0 (L), and the motor M _FR is biased in the forward direction to close and drive the FR window.

After this, S11-S13 -...- S17 -...- S21 -...
-S2-S3-S4-S5-S6-S9-S10-S11-S13 -...
..When the FR window is fully closed in the loop, switch MS
_{Since FR} is turned on, the process proceeds from S10 to S12, where both output ports O ₀ and O ₁ are set to 1 (H) and motor M
Deactivate _FR and set the "FR fully closed" flag. After setting the "FR fully closed" flag, the process proceeds from S9 to S13.

In S13, the presence or absence of the "FL fully closed" flag is checked. This "F
If the "L fully closed" flag is present, the FL window is already in the fully closed state, so the process proceeds to S17, but if the "FL fully closed" flag is not present, the FL window is not yet in the fully closed state. Check the status of MS _FL . Since the FL window is not fully closed,
Naturally, the switch MS _FL is off, and at S15, the output port O _{2 is set} to 1 (H) and the output port O ₃ is set to 0 (L) to energize the motor M _FL in the forward direction to close and drive the FL window. To do.

After this, S15-S17 -...- S21 -...- S2-S3-S4
-S5-S6-S9 -...- S13-S14-S15-S17 -...
・ When the FL window is fully closed in the loop, switch MS _FL
Is turned on, the process proceeds from S14 to S16, where both output ports O ₂ and O ₃ are set to 1 (H) and the motor M _FL
Deactivate and set the "FL fully closed" flag. "FL fully closed"
After setting the flag, the process proceeds from S13 to S17.

In S17, the presence or absence of the "RR fully closed" flag is checked. This "R
If the "R fully closed" flag is present, the RR window is already in the fully closed state, so the process proceeds to S21.If the "RR fully closed" flag is not present, the RR window is not yet in the fully closed state. Check the status of MS _RR . Since the RR window is not fully closed,
Naturally, the switch MS _RR is off, and in S19, the output port O _{4 is set} to 1 (H) and the output port O ₅ is set to 0 (L), and the motor M _RR is forwardly biased to close and drive the RR window. To do.

After this, S19-S21 -...- S2-S3-S4-S5-S6-S9-
...- S13 -...- S17-S18-S19-S21 -...
・ When the RR window is fully closed in the loop, switch MS _RR
Is turned on, the process proceeds from S18 to S20, where both output ports O ₄ and O ₅ are set to 1 (H) and the motor M _RR
Deactivate and set the "RR fully closed" flag. "RR fully closed"
After setting the flag, the process proceeds from S17 to S21.

In S21, the presence or absence of the "RL fully closed" flag is checked. This "R
If there is the "L fully closed" flag, the RL window is already in the fully closed state, so the process returns to S2.
Since the RL window is not yet in the fully closed state, the state of the switch MS _RL is examined at S22. Since the RL window is not fully closed, the switch MS _RL is naturally off, and the output port O _{6 is set} to 1 at S23.
(H), the output port O ₇ is set to 0 (L), and the motor M _RL is forwardly biased to close and drive the RL window.

After this, S23-S2-S3-S4-S5-S6-S9 -...- S13-
...- S17 -... S21-S22-S23-S2--,
In this loop, when the RL window is fully closed, the switch MS _RL is turned on, so the process proceeds from S22 to S24, where the output port O ₆
Set both O and O ₇ to 1 (H) to deactivate the motor M _RL and set the "RL fully closed" flag. After setting the "RL fully closed" flag, the process proceeds from S21 to S2.

As described above, the MPU7 controls the opening and closing of each vehicle window.

In the above-described embodiment, the detection electrode is provided at the portion of the seat cushion on which the occupant sits, but another arrangement of the detection electrode will be described. FIG. 3c shows the electrode EL _{FR on} the periphery of the cysupport 21, that is, the part where the occupant sits.
It is an example of equipping.

FIG. 4a is a side view showing an example in which the seat back 22 is equipped with the electrode EL _FR . In this, as shown in the front view of FIG. 4a, the arrangement to equip the part where the occupant leans back and the
As shown in the front view of FIG. 4a, there is a side support 23, that is, an arrangement in which the side support 23 is equipped on the periphery of a portion on which an occupant leans. By equipping the electrodes in two or more arrangements of the above four arrangements, it is possible to further widen the detection range of each seat. In this case, each electrode is connected in parallel to the detection circuit DET.
The presence or absence of an occupant may be detected by connecting to the detection terminal of _FR , or by providing a detection circuit DET _FR , a DC amplification circuit AMP and a binarization circuit BIN for each, and taking the logical sum of the output signals.

Further, in the above embodiment, the seat cushion trim cover
Although the electrode is formed on the wadding 51 of 20 by sputtering of a conductive paint, it may be formed by adhering an aluminum foil or using a woven cloth of conductive fiber for the wadding cover 52. .

FIG. 1d shows another embodiment of the detection circuit and the binarization circuit. In this, 13 is an oscillator that oscillates a signal of a frequency according to the capacity of the external capacitor (the frequency decreases as the capacity of the capacitor increases) (for example, for a timer
IC555), 14 are counters for counting the frequency of the signal oscillated by the oscillator 13, and 15 is a digital comparator for comparing the output data of the counter 14 with a reference value.
Here, the occupant detection capacitor C _FR is connected as an external capacitor of the oscillator 13. That is, when the passenger is seated in the FR seat and the occupant detection capacitor C _FR increases, the output frequency of the oscillator 13 decreases.

The reference value is the counter 1 when there is no passenger MAN seated in the FR seat.
Output data of 4 (capacitor C _FR for seating detection at that time)
The frequency is slightly lower than the frequency at which the oscillator 13 oscillates) (hunting is prevented). The digital comparator 15 compares the output data of the counter 14 with the reference value. When the output data exceeds the reference value, a signal “1” indicating “no seating” is output, and when the output data becomes less than or equal to the reference value. , A signal “0” indicating “seated” is output.

〔The invention's effect〕

As described above, according to the present invention, a flexible conductive layer of a seat cushion and a flexible conductive layer of a seat back,
By detecting a change in capacitance between the on-vehicle conductor and the presence or absence of an occupant, presence / absence of seating on the occupant seat can be detected in a non-contact manner.

Since the flexible conductive layer provided in the seat cushion of the vehicle seat has a wide surface, seating of a small passenger such as an infant or a child can be reliably detected. Since the seat back of the car seat is also provided with a flexible conductive layer, the flexible conductive layer is distributed so as to cover the rear half of the upper half of the occupant, so that the occupant detection range is wide and infants, children, etc. The occupant with a small body has a high reliability of seating detection, and the possibility of detecting no seating due to the displacement of the body of the occupant on the vehicle seat or the posture change is reduced, and the seating detection reliability is extremely high.

In addition, since the conductive layer is flexible and is inside the surface layer of the sheet, it is not damaged by impact, vibration, etc., and is not damaged or worn by collision or rubbing of objects, and is excellent in durability and reliability. .

By equipping each of the vehicle seats with the occupant detection device of the present invention, it is possible to know whether or not each of the vehicle seats has a seat, and the distribution of the seated persons. It can be controlled in a manner suitable for the user. In addition, automatic control for security can be performed, such as automatically closing the vehicle window when all seats are not seated.

[Brief description of drawings]

FIG. 1a is a block diagram showing an embodiment of the present invention, FIG. 1b is a circuit for explaining the operation of the detection circuit DET _FR shown in FIG. 1a, FIG. 1c is a graph showing the characteristics of a diode, and 1d. The figure is a block diagram showing another embodiment of the present invention. FIG. 2a is a perspective view in which a part of the vehicle seat is crushed, and FIG. 2b is a perspective view showing the structure of the seat cushion trim cover 30 shown in FIG. 2a. FIGS. 3a, 3b, 3c, 4a, 4b and 4c are a side view and a front view showing the arrangement of the detection electrodes incorporated in the sheet. FIG. 5a is a circuit diagram showing an outline of a power window control system using the apparatus of the embodiment shown in FIG. 1a, and FIG.
5a is a circuit diagram showing details of the input switch circuit 8 of the system shown in FIG. 5a, and FIG. 5c is an occupant detection device of the system shown in FIG. 5a.
It is a block diagram which shows the detail of 12. Fig. 6a is a side view showing the outline of the mechanism of the passenger door of the vehicle,
Fig. 6b is an enlarged perspective view of the electric mechanism, and Fig. 6c is Fig. 6a.
It is a VIC-VIC sectional view of the drawing. FIG. 7 is a flow chart showing a schematic operation of the MPU 7 of the system shown in FIG. 5a. FIG. 8a is a partial sectional view showing a conventional seating switch,
FIG. 8b is a partially enlarged view thereof. 1: Passenger door, 2: Window glass 3 ₁ , 3 ₂ : Link arm 4: Fan gear 5: Worm wheel assembly 6: Weather strip 7: Microcomputer 8: Input switch circuit 9: Drive circuit, 10: Power supply Circuit 11: Current detection circuit 12: Occupant detection device 13: Oscillator, 14: Counter 13,14: (Detection means) 15: Digital comparator (Detection processing means) 20: Seat cushion 21: Cyclic support, 22: Seat back 23: Side support 24: Headrest 30: Seat cushion trim cover 31: Seat cushion pad 32: Seat cushion pad support 33: Seat cushion spring 34: Seat cushion frame 40: Seat back trim cover 41: Seat back pad 42: Seat back pad support 43: Seat back spring 44: Seat back frame 50: Skin (skin) 51: Wadding (conductive sheet on the back of the skin) 52: Wadding cover 100: Seating switch 101: Movable contact, 102: Fixed contact EL _FR : Detection electrode (conductive layer) ROOF: Roof, Flor: Floor ROOF, Flor: (Vehicle conductor, body) DET _FR : Detection circuit (Detection means) OSC: Oscillator, LPF: Low-pass filter Co, C, Cs, C _FR : Capacitors D ₁ , D ₂ , D ₃ , D ₄ : Diode R, r: Resistor, MAN: Crew AMP: DC amplifier BIN : Binarization circuit (detection processing means) DOR _FR : Door MS _FL : Limit switch RY1, RY2, RY3, RY4, RY5, RY6, RY7, RY8: Relay

Claims (3)

[Claims] 1. A flexible seat cushion conductive layer provided inside a seat cushion surface layer of a vehicle seat and having a wide surface covering substantially the entire surface on which an occupant sits; an inner side of a seat back surface layer of the vehicle seat. A flexible seat back conductive layer having a surface along the surface; at least one surface of the seat cushion conductive layer and the seat back conductive layer between at least a part of an occupant seated on the vehicle seat. Detecting means for detecting a change in capacitance between the on-vehicle conductor and the seat cushion conductive layer and the seat back conductive layer, which face each other; and the on-vehicle seat when the detecting means detects an increase in capacitance. An occupant detection device, comprising: a detection processing unit that generates an electric signal indicating that the vehicle is seated. 2. The occupant detection device according to claim 1, wherein the on-vehicle conductor is a vehicle body. 3. The occupant detection system according to claim 1, wherein the flexible conductive layer is a conductive sheet such as a cloth woven with conductive threads or a film coated with a conductive material. apparatus.