JP2007099204A - Vehicle seat device - Google Patents

Abstract

There is provided a vehicle seat device that can be simplified in structure and can suppress reduction in occupant detection accuracy by an occupant detection device when a heating wire of a heater device is disconnected.
A vehicle seat device includes an occupant detection device (5) having a sensor electrode (11) that is provided on a seat and generates an electrostatic capacitance that changes in accordance with the state of the seat, a cushion heater (12) for heating the seat, and a back. And a heater device 6 having a heater 13. The cushion heater 12 and the back heater 13 are electrically connected in parallel.
[Selection] Figure 2

Description

  The present invention relates to a vehicle seat device including an occupant detection device and a heater device.

  2. Description of the Related Art Conventionally, when an airbag is provided to protect an occupant of a vehicle seat such as an automobile, for example, a vehicle seat device for determining various states of the target seat (for example, presence or absence of an occupant) Is provided with an occupant detection device. In addition, such a vehicle seat device is also known that is provided with a heater device for heating the seat to a required temperature.

  For example, Patent Document 1 includes an occupant detection device having an oscillation electrode and a reception electrode disposed on a seat cushion and a seat back of a seat, and a heater device having a heating wire disposed below the oscillation electrode. Things have been proposed. The occupant detection device improves the reliability of determination accuracy by making redundant determinations of various states (adult seating, etc.) of the seat using these oscillation electrodes and reception electrodes.

On the other hand, Patent Document 2 includes an occupant detection device having a sensor electrode that generates a capacitance that changes according to the state of the seat, a heater device having a heating wire, and a control means for selectively operating them. Have been proposed. That is, the heater device has a heating wire in which a heating wire for heating the seat cushion and a heating wire for heating the seat back are electrically connected in series, and the control means is an occupant detection device. The period for cutting the upstream side and the downstream side of the above-described heating wires connected in series from the positive electrode and the ground electrode of the DC power supply is set in accordance with the period for operating the power source.
JP 2003-80989 A (page 5-6, FIG. 5) JP 2004-196196 A

By the way, in Patent Document 1, since the receiving electrode is required in addition to the oscillation electrode, the number of parts is increased, for example, the peripheral circuit is doubled, and the cost is inevitably increased.
On the other hand, in Patent Document 2, since the control means for selectively switching the operation period between the occupant detection device and the heater device is required, the structure becomes complicated and the cost is inevitably increased.

  Therefore, in order to simplify the structure, the present applicant has studied that the occupant detection device and the heater device are selectively operated independently of each other instead of the selective operation of the occupant detection device and the heater device as in Patent Document 2. FIG. 5 is a circuit diagram schematically showing the heater device independent of the occupant detection device. As shown in the figure, according to Patent Document 2, the heater device 90 is configured such that a heating wire 91 for heating the seat cushion and a heating wire 92 for heating the seat back are electrically connected at the connection point T. Heating wire connected in series. One end of the heating wire 91 is connected to the ground electrode 93, and one end of the heating wire 92 is connected to the plus electrode 94 of the DC power source via the heater operation switch 95. The heater operation switch 95 is a switch that conveniently represents a function as an operation switch by an occupant and a function as a switch for heating control by a control unit included in the heater device.

  It is assumed that the occupant detection device has a sensor electrode according to Patent Document 2. In this case, since the seat can be heated by the heater device regardless of the operation of the occupant detection device, the structure of the entire vehicle seat device including simplification of control can be simplified.

  However, since the heating wire provided in the heater device for vehicles is repeatedly bent by getting on and off by a person due to the nature of the environment at the use position, the heating wire may break due to fatigue. In such a heating wire connected in series, if any one of the positions a to f shown in FIG. 5 is disconnected, the disconnected heating wire generates a floating potential, which causes disturbance of the sensor electrode. There is. For example, when the heating wire is disconnected at the position a closest to the heater operation switch 95, since almost the entire heating wire is connected to the ground electrode 93, there is almost no influence of the floating potential on the sensor electrode. When the electrode 93 is disconnected at a position f closest to the electrode 93, the sensor electrode is affected by a significant floating potential due to the heating wires 91 and 92 on the seat cushion side and the seat back side. In other words, the capacitance generated by the sensor electrode changes according to the disconnection position only by disconnecting one part of the heating wire, and the detection accuracy of the seat state by the occupant detection device based on the capacitance is reduced. Will be.

  An object of the present invention is to provide a vehicle seat device that can simplify the structure and can suppress a reduction in occupant detection accuracy by the occupant detection device when the heating wire of the heater device is disconnected. is there.

  In order to solve the above problems, the invention according to claim 1 is directed to an occupant detection device having a sensor electrode that is provided on a seat and generates a capacitance that varies depending on the state of the seat, and the seat is heated. In a vehicle seat device comprising a heater device having a plurality of heating wires for performing the above, the summary is that the plurality of heating wires are electrically connected in parallel.

  According to a second aspect of the present invention, in the vehicle seat device according to the first aspect, the plurality of heating wires includes a first heating wire for heating a seat cushion of the seat, and a seat back of the seat. It consists of the second heating wire for heating.

  According to each of the above configurations, the plurality of heating wires are electrically connected in parallel, so that any one of the heating wires can be used regardless of whether or not the plurality of heating wires are being fed by a DC power source. If only one portion of the heat wire is disconnected, the entire heating wire is connected in a circuit and no floating potential is generated in the disconnected heating wire. Therefore, the influence of the floating potential on the sensor electrode is eliminated, and the capacitance generated by the sensor electrode is not changed by the disconnection of the heating wire, and the seat state detection accuracy by the occupant detection device based on the capacitance is improved. Is done.

  In addition, since the occupant detection device and the heater device are independent from each other, there is no need to give an appropriate relationship to the operation between the occupant detection device and the heater device. Simplified.

  According to a third aspect of the present invention, in the vehicle seat device according to the first or second aspect, the occupant detection device is interposed between at least one of the plurality of heating wires and the sensor electrode. The present invention includes a shield electrode, and the same potential means for making the sensor electrode and the shield electrode have the same potential.

  According to this configuration, a shield electrode is interposed between at least one heating wire of the plurality of heating wires and the sensor electrode, and the sensor electrode and the shield electrode have the same potential by the same potential means. Is done. As a result, capacitive coupling between at least one heating wire of the plurality of heating wires and the sensor electrode is suppressed, and a change in capacitance generated by the sensor electrode becomes more obvious, and the capacitance The seat state detection accuracy by the occupant detection device based on the above is further improved.

  In invention of Claim 1 thru | or 3, a structure can be simplified and reduction of the passenger | crew detection accuracy by the passenger | crew detection apparatus at the time of the disconnection of the heating wire of a heater apparatus can be suppressed.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a vehicle seat device of the present embodiment. As shown in the figure, a seat 2 on which a person 1 can be seated is mounted on the vehicle. A flat sensor electrode 11 is embedded in the seat cushion 3 forming the seating portion of the seat 2 so as to expand along the seating portion. A capacitor C1 is provided between the sensor electrode 11 and a conductor (such as a person 1 as an occupant) on the seat cushion 3, and a capacitor C2 is provided between the conductor and the ground electrode GND formed by the vehicle body and the seat skeleton. Each is formed. Accordingly, the capacitance formed by the capacitors C1 and C2 varies depending on the presence or absence of the person 1.

  Further, a cushion heater 12 as a first heating wire, one end of which is electrically connected to the ground electrode GND, is embedded in the seat cushion 3 in a meandering manner so as to reach the entire seating portion. The cushion heater 12 is for heating the seat cushion 3 to a required temperature. The sensor electrode 11 is arranged on the surface side of the seat cushion 3 relative to the cushion heater 12, that is, on the person 1 side.

  Further, the seat back 4 forming the backrest portion of the seat 2 has a mode in which the back heater 13 as a second heating wire, one end of which is electrically connected to the ground electrode GND, meanders so as to spread over the entire backrest portion. Buried. The back heater 13 is for heating the seat back 4 to a required temperature.

  As shown in FIG. 1, the cushion heater 12 is capacitively coupled to the conductor on the seat cushion 3 by a parasitic capacitance Cp1, and the back heater 13 is on the seat cushion 3 by a parasitic capacitance Cp2. Capacitively coupled to the conductor. Therefore, the capacitance obtained by combining the capacitors C1 and C2 and the parasitic capacitances Cp1 and Cp2 changes depending on the presence or absence of the person 1. That is, the sensor electrode 11 generates an electrostatic capacitance that changes depending on the state of the sheet 2, that is, the presence or absence of the person 1, with the ground electrode GND.

  FIG. 2A is a block diagram illustrating an electrical configuration of the occupant detection device 5 having the sensor electrode 11, and FIG. 2B is an electrical diagram of the heater device 6 having the cushion heater 12 and the back heater 13. It is a block diagram which shows a typical structure. Hereinafter, a description will be given with reference to FIGS.

  As shown in FIG. 2A, an occupant detection ECU (Electronic Control Unit) 20 that constitutes a control unit of the occupant detection device 5 is electrically connected to the sensor electrode 11. That is, as shown in FIG. 1, the pulse generator 21 of the occupant detection ECU 20 is electrically connected to the sensor electrode 11 via the resistor 22. The resistor 22 forms a delay circuit with the combined capacitance of the capacitors C1 and C2 and the parasitic capacitances Cp1 and Cp2 formed between the sensor electrode 11 and the ground electrode GND, and a pulse signal is received from the pulse generator 21. When output, a signal delayed in rising and falling is output from the connection point T1 between the resistor 22 and the sensor electrode 11 according to the CR time constant determined by the combined capacitance and the resistance of the resistor 22. The connection point T1 is connected to the CR time constant detection circuit 23 of the occupant detection ECU 20, and the CR time constant detection circuit 23 outputs a detection signal corresponding to the CR time constant to the determiner 24 of the occupant detection ECU 20. . Based on the detection signal from the CR time constant detection circuit 23, the determiner 24 determines whether or not the CR time constant (the combined capacity of the capacitors C1 and C2 and the parasitic capacitors Cp1 and Cp2) corresponds to the presence of the person 1. Determined.

  As shown in FIG. 2A, the occupant detection ECU 20 is connected to the airbag ECU 30 of the airbag device 7 and outputs a determination signal corresponding to the determination result in the determiner 24. The airbag ECU 30 controls driving of the airbag 31 based on the determination signal. For example, if the determination signal corresponds to the presence of the person 1, the airbag ECU 30 permits the operation of the airbag 31 under a predetermined condition. On the other hand, the airbag ECU 30 prohibits the operation of the airbag 31 when the determination signal corresponds to the absence of the person 1 (such as a wearing state of the child restraint device).

  As shown in FIG. 2B, the cushion heater 12 and the back heater 13 are electrically connected in parallel with one end and the other end connected at connection points T2 and T3. And the heater control relay 40 which comprises the control part of the heater apparatus 6 is electrically connected to the said connection points T2, T3. The heater control relay 40 is connected to the positive electrode 41 of the DC power supply and to the ground electrode GND. By selectively connecting the positive electrode 41 and the connection point T2, the seat 2 is brought to a required temperature. Control heating. The heater control relay 40 is always connected between the ground electrode GND and the connection point T3.

  FIG. 3 is a circuit diagram schematically showing the heater device 6. As shown in the figure, the connection point T2 of the heater device 6 is connected to the positive electrode 41 via the heater operation switch 42, and the connection point T3 is connected to the ground electrode GND. The heater operation switch 42 is a switch that conveniently represents the function of the heater control relay 40 as a switch.

  In the cushion heater 12 and the back heater 13 thus connected in parallel, for example, any one of the positions a to c of the cushion heater 12 or any one of the positions d to f of the back heater 13 is disconnected. To do. At this time, if the heater operation switch 42 is off, that is, if power is not being supplied from the DC power supply, the entire circuit is connected to the ground electrode GND side regardless of the disconnection at any position a to f. No floating potential is generated in the disconnected cushion heater 12 or back heater 13.

  On the other hand, if the heater operation switch 42 is ON, that is, if power is being supplied from a DC power source, the entire circuit is connected to the positive electrode 41 and the ground electrode GND side regardless of the disconnection at any position af. Therefore, no floating potential is generated in the disconnected cushion heater 12 or back heater 13. In this case, a voltage corresponding to a voltage drop is generated at each position of the cushion heater 12 or the back heater 13, but since this voltage is a direct current component, the capacitance generated by the sensor electrode 11 is affected by this voltage. There is nothing.

  As described above, the influence of the floating potential on the sensor electrode 11 is eliminated, and the capacitance generated by the sensor electrode 11 does not change due to the disconnection of the cushion heater 12 or the back heater 13. That is, the capacitance generated by the sensor electrode 11 regardless of whether the heater operation switch 42 is on or off, that is, whether or not power is being supplied by a DC power source, regardless of whether the position a to f is disconnected. There will be no disturbance.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) In this embodiment, the cushion heater 12 and the back heater 13 are electrically connected in parallel, so that the cushion heater 12 and the back heater 13 are supplied with power from a DC power source. If any one of the locations is disconnected, a floating potential is not generated in the cushion heater 12 or the back heater 13 in which the entire heating wire is connected in a circuit. Therefore, the influence of the floating potential on the sensor electrode 11 is eliminated, and the capacitance generated by the sensor electrode 11 does not change due to the disconnection. The detection accuracy of the presence or absence of can be improved.

  In addition, since the occupant detection device 5 and the heater device 6 are independent from each other, it is not necessary to have an appropriate relationship in the operation between the occupant detection device 5 and the heater device 6, and the entire vehicle seat device. The structure is simplified.

  (2) Since the reliability of either one of the occupant detection device 5 and the heater device 6 is not impaired by the occurrence of an abnormality, the signal transmission / reception for sharing the fault diagnosis information is performed. This configuration can also be eliminated.

(3) In this embodiment, since the passenger | crew detection apparatus 5 and the said heater apparatus 6 are mutually independent structures, the freedom degree of each design can be increased.
(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In addition, since 2nd Embodiment is the structure which added the shield electrode etc. in 1st Embodiment, about the same structure, the same code | symbol is attached | subjected and the description is partially abbreviate | omitted.

  FIG. 4 is a schematic diagram showing the vehicle seat device of the present embodiment. As shown in the figure, a flat shield electrode 51 is embedded in the seat cushion 3 so as to expand along the seating portion. The shield electrode 51 is interposed between the sensor electrode 11 and the cushion heater 12. The shield electrode 51 is electrically connected to the connection point T1 through a buffer circuit 52 as the same potential means provided in the occupant detection ECU 20. The buffer circuit 52 has an operational amplifier to constitute a voltage follower, and the sensor electrode 11 and the shield electrode 51 have the same potential. Therefore, capacitive coupling between the cushion heater 12 and the sensor electrode 11 is suppressed by the shield electrode 51, and a change in electrostatic capacitance generated by the sensor electrode 11, that is, a combined capacitance of the capacitors C1 and C2 and the parasitic capacitances Cp1 and Cp2. Change becomes more apparent.

As described above in detail, according to the present embodiment, the following effects can be obtained in addition to the same effects as those of the first embodiment.
(1) In the present embodiment, the shield electrode 51 is interposed between the cushion heater 12 and the sensor electrode 11, and the sensor electrode 11 and the shield electrode 51 are set to the same potential by the buffer circuit 52. As a result, the capacitive coupling between the cushion heater 12 and the sensor electrode 11 is suppressed, and the change in capacitance generated by the sensor electrode 11 becomes more obvious, and the occupant detection device 5 based on the capacitance detects the seat 2. The detection accuracy of the state, that is, the presence or absence of the person 1 can be further improved.

In addition, you may change the said embodiment as follows.
In each of the above embodiments, the potential at the connection point T3 of the cushion heater 12 and the back heater 13 may have a predetermined potential difference with respect to the potential of the ground electrode GND.

  In each of the above embodiments, the seat cushion 3 may be divided into a plurality of regions, and the cushion heater 12 may be divided into a plurality of heating wires that reach each region. Alternatively, the seat back 4 may be divided into a plurality of regions, and the back heater 13 may be divided into a plurality of heating wires that reach each region. Even in each of these cases, if only one location of any one heating wire is disconnected by electrically connecting a plurality of heating wires in parallel, the entire heating wire is connected in a circuit and disconnected. There is no floating potential in the heated wire.

The schematic diagram which shows the 1st Embodiment of this invention. (A) and (b) are block diagrams showing an electrical configuration of the embodiment. The circuit diagram which shows a heater apparatus. The schematic diagram which shows the 2nd Embodiment of this invention. The circuit diagram which shows the conventional heater apparatus.

Explanation of symbols

  GND ... ground electrode, 2 ... seat, 3 ... seat cushion, 4 ... seat back, 5 ... passenger detection device, 6 ... heater device, 11 ... sensor electrode, 12 ... cushion heater as first heating wire, 13 ... second Back heater as heating wire, 51... Shield electrode, 52... Buffer circuit as same potential means.

Claims (3)

A vehicle seat device comprising: an occupant detection device having a sensor electrode that is provided on a seat and generates a capacitance that varies according to the state of the seat; and a heater device having a plurality of heating wires for heating the seat. In
The vehicle seat device, wherein the plurality of heating wires are electrically connected in parallel. The vehicle seat device according to claim 1,
The plurality of heating wires include a first heating wire for heating the seat cushion of the seat and a second heating wire for heating the seat back of the seat. The vehicle seat device according to claim 1 or 2,
The occupant detection device is
A shield electrode interposed between at least one of the plurality of heating wires and the sensor electrode;
A vehicle seat device comprising: equipotential means for making the sensor electrode and the shield electrode have the same potential.

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