JP5646536B2 - Sensor belt device - Google Patents

Description

  The present invention relates to a sensor belt device that warns an occupant when it is determined to be dangerous, such as when the occupant is in an inappropriate driving posture or when a seat belt is not worn.

  Currently popular vehicles are equipped with various safety devices such as seat belts and airbags for protecting passengers in an emergency such as a collision accident. Many of these safety devices are equipped with sensors and operate automatically and quickly due to the occurrence of an impact or the like. However, if the occupant is not in the correct posture, the function will be reduced. For example, if an occupant takes an incorrect posture such as one-handed driving and a gap is generated between the seat belt webbing (hereinafter simply referred to as webbing) and the body, the binding force is reduced.

  For example, Patent Literature 1 discloses a driver state determination device that issues a warning or the like when a driver is in an inappropriate state for driving as a technique for alerting a passenger. In Patent Document 1, a driver is photographed with a camera in a vehicle interior, and the state of the driver is determined by acquiring the degree of wakefulness and attention concentration of the occupant from the image.

JP 2007-265377 A

  In Patent Document 1, since it is determined using a camera whether or not an alarm is to be performed, a large-scale configuration is unavoidable. At present, the downsizing of vehicles tends to proceed more and more, and a mechanism for alerting passengers or the like is desired to have a simpler configuration.

  In view of such a problem, the present invention accurately detects the driving posture, etc. even for passengers with different physiques, when taking an inappropriate driving posture, when the seat belt is not attached, etc. It is an object of the present invention to provide a sensor belt device that gives a warning.

  In order to solve the above-described problems, a typical configuration of a sensor belt device according to the present invention includes a slide seat that is slidable in a vehicle compartment, and is installed on one side surface of the slide seat, and fixes the lower end of the seat belt webbing. A lap anchor; a first electrode provided on a steering wheel or a slide seat; a belt-like resistance heating element; a second electrode provided on a seat belt webbing and constituting an electrode pair with the first electrode; A heater control unit that supplies power to two electrodes to generate heat, a transmission unit that transmits an electric signal of a predetermined frequency to the electrode pair, and whether or not the parameters of the electric signal that has passed through the electrode pair have deviated from a predetermined threshold And a warning unit that gives a predetermined warning when the parameter deviates from the threshold value.

  In the sensor belt device, when an occupant wears a seat belt webbing (hereinafter referred to as webbing) and grips the steering wheel, or when an occupant sits on the seat and wears the seat belt webbing, the electrode belt is formed between the electrodes. The crew will be intervened. When an electric signal is passed through the electrode pair, the electric signal parameter (for example, voltage value) is affected by whether or not an occupant is present between the electrode pair. By utilizing this, in the above configuration, it is possible to electrically detect whether or not the occupant is in the correct posture / state.

  In the above configuration, the lap anchor is installed on the slide sheet, and the lap anchor slides together with the slide sheet. Usually, a seat belt retractor (hereinafter referred to as a retractor) is fixed to the vehicle body side, and when the slide seat is slid, the webbing is gradually pulled out from the retractor. However, since the lap anchor slides together with the slide seat, the area of the webbing that is in contact with the occupant does not change the positional relationship with the occupant before and after the slide movement. That is, even if the seat position is changed in accordance with the occupant's physique, the contact state of the second electrode with respect to the occupant does not change. Therefore, according to the said structure, a driving posture etc. can be detected accurately, even if it is a passenger | crew of a different physique.

  In the sensor belt device, the seat belt webbing also functions as a so-called heater belt. Since the heater belt is directly heated by contacting the occupant, the heat efficiency is good. In particular, the belt-like resistance heating element can ensure a wide contact area with the occupant. In addition, because the contact area is large, the efficiency of electrical transmission with the occupant is also increased, and since the resistance heating element is also the second electrode, in the above configuration, the two functions of the heater and the electrode are efficiently exhibited. And simplification of the configuration.

  The sensor belt device may further include a seat belt buckle that is installed on the other side surface of the slide seat and fixes the seat belt tongue plate. If it is this structure, since a seatbelt buckle also slides and moves with a slide seat, the positional relationship with respect to the passenger | crew of a webbing does not change before and after a slide movement, and the contact condition with respect to the passenger | crew of a 2nd electrode can be maintained suitably.

  The sensor belt device may further include a low-pass filter including a capacitor formed of an electrode pair. In this configuration, the occupant is interposed as a dielectric in the capacitor. Usually, the capacitance of the capacitor affects the cutoff frequency of the low-pass filter. In the above configuration, the capacitance of the capacitor changes depending on whether the occupant wears the seat belt webbing, whether the steering wheel is held with both hands, or the like. Accordingly, the degree of decrease in the voltage peak value of the electrical signal that has passed through the low-pass filter also varies. Therefore, by measuring the voltage peak value of the electric signal downstream of the low-pass filter, it is possible to determine whether or not the occupant is riding in the correct posture / state.

  According to the present invention, even if the occupants have different physiques, a sensor that accurately detects the driving posture, etc., and warns when the driving posture is inappropriate or when the seat belt is not worn. A belt device can be provided.

It is the figure which illustrated the outline of the sensor belt device concerning the present invention. It is an exploded view of the 2nd electrode of FIG. It is a schematic block diagram of the sensor belt apparatus of FIG. FIG. 4 is a circuit diagram showing a part of the sensor belt device of FIG. 3. FIG. 5 is a diagram illustrating characteristics of electric signals downstream of LPF 1 in FIG. 4. It is the figure which contrasted the slide movement of the slide sheet | seat of FIG. 1, and a comparative example. It is the figure which illustrated CR circuit as the 1st other example for detecting a crew member's capacitance. It is the figure which illustrated the automatic balance bridge as the 2nd other example for detecting a crew member's capacitance. It is a modification of the sensor belt apparatus of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Sensor belt device)
FIG. 1 is a diagram illustrating an outline of a sensor belt device according to the present invention. FIG. 1A is a perspective view of a seat space on the right side of the front portion of the vehicle as viewed from the right side (the vehicle outer side). The sensor belt device according to the present embodiment (hereinafter referred to as the sensor belt 100) determines whether or not the occupant 102 is correctly wearing the seat belt 104 and whether or not an appropriate driving posture is taken. Then, when the seat belt 104 is not worn or in an inappropriate driving posture, or when the vehicle is in a dangerous state as a result of comprehensive judgment by adding information such as a vehicle speed and a brake state, the passenger 102 is informed. Warning.

  In making the above determination, in the sensor belt 100, the steering wheel 108 is provided with the first electrode 110, and the webbing 106 is provided with the second electrode 112. In this embodiment, when the occupant 102 wears a seat belt webbing (hereinafter referred to as webbing 106) and grips the steering wheel 108, a dielectric is formed between the electrode pair constituted by the first electrode 110 and the second electrode 112. A capacitor C1 (FIG. 3) with the occupant 102 interposed as a body is formed.

  The first electrode 110 is provided on the grip portion 114 (ring portion) of the steering wheel 108 so that the first electrode 110 can easily come into contact with the passenger 102. The first electrode 110 can be realized by arranging a metallic contact at a predetermined position, but it can also be realized by covering the surface of the grip portion 114 with a conductive fiber or applying a conductive paint.

  The second electrode 112 is installed in a region of the webbing 106 that contacts the abdomen of the occupant 102 in particular. The webbing 106 is configured as a so-called heater belt having a heating function, and the second electrode 112 also has a function as a heating element.

  The slide seat 142 illustrated in FIG. 1A is capable of sliding in the vehicle front-rear direction. The lower end side of the webbing 106 is installed on one side surface of the seat cushion 140 of the slide seat 142 by a wrap anchor 150. 1B illustrates the slide seat 142 of FIG. 1A as viewed from the left side of the vehicle. In this embodiment, a seat belt buckle (hereinafter referred to as a buckle 152) is also a seat cushion. 140 on the other side surface. The buckle 152 is a part where the tongue plate 154 is inserted and fixed. In the present embodiment, the wrap anchor 150 (see FIG. 1A) and the buckle 152 are installed on the seat cushion 140, so that the webbing 106 can be slid along with the slide seat 142.

  FIG. 2 is an exploded view of the second electrode 112 of FIG. The second electrode 112 uses a resistance heating element 116 as a main component. The resistance heating element 116 is a part that receives an electrical signal flowing from the first electrode 110 through the body of the occupant 102 (see FIG. 1), and is also a heating element when functioning as a heater belt. The resistance heating element 116 has a strip shape, and two electrode wires 118a and 118b are connected to each other. These electrode wires 118a and 118b are used to flow received electric signals to other places and to receive power supply when functioning as a heater belt. And the passenger | crew side of these 2nd electrodes 112 is covered with the protection member 120 comprised with the insulating fiber etc. FIG. The main components of the second electrode 112 may be a planar structure having both heat generation and conductivity. In addition to the resistance heating element 116, for example, a so-called carbon heater using carbon fiber, Aluminum foil heaters can be used.

  FIG. 3 is a schematic configuration diagram of the sensor belt device of FIG. 1. As described above, in the sensor belt 100, when the occupant 102 wears the webbing 106 and grips the steering wheel 108, the capacitor C <b> 1 is connected between the first electrode 110 of the steering wheel 108 and the second electrode 112 of the webbing 106. 4) is configured. The capacitor C1 forms part of a low-pass filter (LPF1), and the occupant 102 is included in the capacitor C1 as a dielectric.

  In determining the driving posture or the like of the occupant 102, first, the transmission unit 124 is provided in the control unit 122 of the sensor belt 100. An electrical signal having a predetermined frequency is transmitted from the transmitter 124. The LPF 1 described above is present at the destination of the electric signal.

  FIG. 4 is a circuit diagram showing a part of the sensor belt device of FIG. The cut-off frequency fc of the LPF 1 is determined by the capacitance (capacitance) of the capacitor C1 (occupant 102 in this embodiment). The equation for obtaining the cut-off frequency fc is Equation 1 below. In the embodiment, the driving posture or the like of the occupant 102 is determined by detecting a parameter (a voltage value in the present embodiment) of the electric signal that has passed through the LPF 1.

Ｃ＝乗員のみかけの静電容量、Ｒ＝抵抗Ｒ１の抵抗値

C = apparent occupant capacitance, R = resistance value of resistance R1

  The apparent capacitance C of the occupant 102 in the above equation 1 varies depending on the contact area between the occupant 102, the first electrode 110, and the second electrode 112 illustrated in FIG. That is, the capacitance C changes depending on whether the occupant 102 wears the webbing 106 and whether the steering wheel 108 is gripped by both hands or one hand. Accordingly, the degree of decrease in the voltage peak value of the electrical signal that has passed through the LPF 1 also varies. In the present embodiment, the determination unit 126 is provided downstream of the LPF 1, and the determination unit 126 measures the voltage peak value of the electric signal to determine whether or not the occupant 102 is in the correct posture / state. doing. As illustrated in FIG. 4, the determination unit 126 is provided with an operational amplifier Op <b> 1, performs peak holding of the electric signal, and monitors the change in the capacitance C at the AD port 128 ahead.

  FIG. 5 is a diagram illustrating the characteristics of the electrical signal downstream of the LPF 1 of FIG. FIG. 5A is a diagram illustrating frequency characteristics of the LPF 1. The amplitude (V) of the electric signal passing through the LPF 1 gradually decreases as the frequency becomes higher than the cutoff frequency fc (transition band). The cut-off frequency fc is obtained by the above-described equation 1. That is, the magnitude of the apparent capacitance C of the occupant 102 of the above equation 1 is reflected in the amplitude of the electric signal in the transition band.

  FIG. 5B is a diagram exemplifying fluctuations in the amplitude (V) of the electric signal due to the apparent capacitance C of the occupant 102. Assuming that the electric signal transmitted from the transmitting unit 124 of FIG. 3 is the signal W1, for example, the passenger 102 wears the webbing 106 and grips the steering wheel 108 with both hands. Then, the electrostatic capacitance C in the above equation 1 increases, and the voltage peak value V2 of the signal W2 that has passed through the LPF1 becomes significantly smaller than the voltage peak value V1 of the signal W1. Further, for example, when the occupant 102 holds the steering wheel 108 with both hands while the webbing 106 is not worn, the capacitance C is small, and the voltage peak value V3 of the signal W3 that has passed through the LPF 1 is the voltage peak value V1. And the voltage peak value V2.

  Therefore, for example, a value between the voltage peak value V2 and the voltage peak value V3 in FIG. It is possible to determine whether or not the occupant 102 is wearing the webbing 106 depending on whether or not the threshold Vi is deviated. Further, for example, by setting a threshold value between the voltage peak value V2 and the voltage peak value when the occupant 102 holds the steering wheel 108 with one hand, it is determined whether or not the occupant 102 is operating one hand. It becomes possible.

  Note that the frequency of the electrical signal transmitted by the transmission unit 124 may be determined within the transition band range of FIG. An electrical signal within this range is suitable because it is easy to acquire a change in the state of the occupant 102 as an amplitude variation.

  When the determination unit 126 in FIG. 3 determines that the occupant 102 is in a dangerous state such as the webbing 106 not being worn by the flow described above, the warning unit 130 is operated via the ECU 128 (Electronic Control Unit), and the occupant A warning is issued to 102. The warning method can be selected as appropriate, for example, by voice notification or lighting of an electric lamp. With these configurations, the sensor belt 100 can prompt the occupant 102 to board in the correct posture and state.

  In the sensor belt 100, the webbing 106 can be slid along with the slide sheet 142. FIG. 6 is a diagram comparing the slide movement of the slide sheet 142 of FIG. 1 with a comparative example. 6A to 6C are the sensor belt 100, and FIGS. 6D to 6F are comparative examples. The sensor belt 10 as a comparative example is different from the sensor belt 100 in that the lap anchor 12 is fixed to the vehicle body side instead of the seat cushion 140.

  Reference is first made to a comparative example. When the slide seat is slid forward from the state of (d), the webbing 106 is gradually pulled out from the retractor 156 fixed to the vehicle body side. Since the lap anchor 12 is fixed to the vehicle body side, the webbing 106 moves relative to the occupant 102 as illustrated in FIG. Particularly, as illustrated in (f), the contact area of the second electrode 112 with the occupant 102 is reduced.

  Therefore, in this embodiment, even if the lap anchor 150 is installed on the seat cushion 140 as illustrated in (a) and is slid as illustrated in (b), it is illustrated in (c). As shown, the positional relationship between the second electrode 112 and the occupant 102 does not change. In particular, in the present embodiment, unlike the buckle 14 of (f), the buckle 152 is also installed on the seat cushion 140. Therefore, the position of the webbing 106 does not change not only over the abdomen 106a but also over the shoulder 106b, and the contact state of the second electrode 112 with respect to the occupant 102 can be suitably maintained. Therefore, according to the sensor belt 100, it is possible to accurately detect the driving posture and the like even if the seat position is changed according to passengers of different physiques.

(Another example for detecting the passenger's capacitance)
In the configuration described above, for example, as illustrated in FIG. 4, the capacitance of the occupant 102 is detected using the LPF 1, and whether or not the occupant 102 is riding in the vehicle in the correct posture / state depending on the size. Is judged. However, it is possible to detect the electrostatic capacity of the occupant 102 even with a configuration other than the LPF 1. Examples are given below.

(CR circuit)
FIG. 7 is a diagram illustrating a CR circuit 160 as a first other example for detecting the capacitance of the occupant 102. The CR circuit 160 in FIG. 7A is an electric circuit including a capacitor C1 (occupant 102) and a resistor R2. In the CR circuit 160, the capacitance of the capacitor C1 can be obtained in relation to the transient characteristics when a pulse (input signal W4) is input. First, when the input signal W4 (FIG. 7B) is input, the voltage of the capacitor C1 rises rapidly. However, the current flowing into the capacitor C1 gradually decreases as the electric charge accumulates, and the voltage (for example, the output signal W5 in FIG. 7C) drops to the same level as the power supply voltage. The time t until the voltage settles becomes longer as the capacitance of the capacitor C1 is larger. Accordingly, by detecting the voltage Vt ₁ (time constant) when the time t ₁ of the output signal W5 has elapsed after the input signal W4 is input, the apparent capacitance of the passenger (for example, FIG. When the capacitance is large, FIG. 7D can be obtained (when the capacitance is small). Accordingly, similarly to the LPF 1 described with reference to FIG. 4, it can be determined whether or not the occupant 102 is wearing the webbing 106 and whether the steering wheel 108 is gripped by both hands or one hand.

(Automatic balancing bridge)
FIG. 8 is a diagram illustrating an automatic balancing bridge 170 as a second other example for detecting the capacitance of the occupant 102. The automatic balancing bridge 170 has the same configuration as that of a basic circuit for inverting amplification of a general operational amplifier. A point P1 in FIG. 8 is an inverting input, and this circuit always operates so that the voltage at the point P1 becomes zero by the action of negative feedback. All the current i flowing from the AC signal source e into the capacitor C1 flows through the feedback resistor R3. Here, the voltage across the capacitor C1 and _{V 1,} the output voltage of the operational amplifier Op2 and _{V 2.} At this time, the output voltage V ₂ is equal to the product (equation 2) of a feedback resistor R3 and current i, the impedance Zx of the capacitor C1 can be expressed as Equation 3 below.

(Equation 2)
V ₂ = i × R3 (Formula 2)

  Here, the impedance Zx can be expressed as Equation 4 below.

Ｗ＝各周波数＝２πｆ、Ｃ＝コンデンサＣ１の静電容量

W = each frequency = 2πf, C = capacitance of capacitor C1

  Then, the following formula 5 can be derived from the above formula 3 and formula 4.

As illustrated in Equation 5 above, if V ₁ and V ₂ are detected, the impedance Zx of the capacitor C 1, that is, the apparent capacitance of the occupant 102 can be obtained. Based on the size, it is possible to determine whether or not the occupant 102 is wearing the webbing 106 and whether the steering wheel 108 is gripped by both hands or one hand.

(Heater belt)
The webbing 106 illustrated in FIG. 1 also functions as a heater belt that heats the occupant 102. For this purpose, the sensor belt 100 is provided with a heater control unit 132 illustrated in FIG. The heater control unit 132 supplies power to the resistance heating element 116 (see FIG. 2) to generate heat. Switching elements 134a and 134b are provided between the heater control unit 132 and the resistance heating element 116. When the heater belt is operated, the switching elements 134a and 134b and the ECU 136 are closed. The heater controller 132 is provided with a thermistor T1. Since the resistance of the thermistor T1 varies depending on the temperature, it is possible to control the heat generation temperature of the resistance heating element 116 according to the temperature in the passenger compartment by using the thermistor T1.

  As illustrated in FIG. 2, connectors 138 a and 138 b for connecting to the heater control unit 132 (see FIG. 3) are provided at the ends of the electrode wires 118 a and 118 b of the resistance heating element 116. In particular, as illustrated in FIG. 1, the connectors 138 a and 138 b are installed to be positioned below the seat cushion 140 when the webbing 106 is attached. If it is below the seat cushion 140, the possibility that the occupant 102 contacts the connectors 138a and 138b is greatly reduced. Therefore, unexpected troubles such as dropout can be prevented.

  The heater belt configured as described above is in contact with the occupant 102 and directly heated, so that it has higher thermal efficiency and is more economical than an air conditioner or the like. Further, the sensor belt 100 employs a belt-like resistance tropical as a heating element, and ensures a wide contact area with the occupant 102. Therefore, not only the heat transfer efficiency is enhanced, but also the electricity transfer efficiency when used as the second electrode 112 is enhanced. Therefore, the sensor belt 100 can efficiently perform the two functions of the heater and the electrode, and simplifies the configuration.

(Modification)
FIG. 9 is a modification of the sensor belt device of FIG. In the sensor belt device illustrated in FIG. 9 (hereinafter referred to as sensor belt 200), the installation position of the first electrode 202 is different from that of the sensor belt 100 in FIG. The first electrode 202 of the sensor belt 200 is installed on the seat back 144 that is easily contacted by the occupant 102 (see FIG. 1) among the slide seats 142. With this configuration, the LPF 1 in FIG. 3 is formed by the seat back 144, the occupant 102, and the webbing 106, and it can be determined whether the occupant 102 has worn the webbing 106. As the first electrode 202, a conductive member may be provided inside the seat back 144, or a conductive fiber may be used for the seat cover.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the embodiments described above are preferred examples of the present invention, and other embodiments can be implemented by various methods. Can be carried out. The invention is not limited to the detailed shape, size, configuration, and the like of the components shown in the accompanying drawings unless otherwise specified in the present specification. In addition, expressions and terms used in the present specification are for the purpose of explanation, and are not limited thereto unless otherwise specified.

  Therefore, it is obvious for those skilled in the art that various changes and modifications can be conceived within the scope of the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  INDUSTRIAL APPLICABILITY The present invention is used for a sensor belt device that warns an occupant when it is judged dangerous, such as when the occupant takes an inappropriate driving posture or when a seat belt is not worn. be able to.

C1 ... capacitor, T1 ... thermistor, P1 ... point, Op1 · Op2 ... operational amplifier, R1 · R2 ... resistor, R3 ... feedback resistor, W4 ... pulse signal, e ... AC signal source, 100 · 200 · 10 ... sensor belt, 102 Occupant, 104, seat belt, 106, webbing, 108, steering wheel, 110, 202, first electrode, 112, second electrode, 114, grip portion, 116, resistance heating element, 118a, 118b, electrode wire, 120 Protective member 122 Control unit 124 Transmission unit 126 Determination unit 128 ECU 130 Warning unit 132 Heater control unit 134a / 134b Switching element 136 ECU 138a / 138b Connector 140 ... Seat cushion, 142 ... Ride seat, 144 ... seat back, 150, 12 ... lap anchor, 152, 14 ... Buckle, 154 ... tongue plate, 156 ... retractor, 160 ... CR circuit, 170 ... automatic balancing bridge,

Claims (2)

A slide seat slidable in the vehicle compartment;
A seat belt webbing for restraining an occupant seated on the slide seat;
The installed on one side of the sliding seat, the lap anchor for fixing the lower end of the seat belt webbing,
A seat belt buckle that is installed on the other side surface of the slide seat and fixes a seat belt tongue plate;
A first electrode provided on a steering wheel or the slide seat;
A strip-shaped resistance heating element, and a second electrode constituting the first electrode and the electrode pairs provided on the seat belt webbing,
A heater controller for supplying power to the second electrode to generate heat;
A transmitter for transmitting an electrical signal of a predetermined frequency to the electrode pair;
A determination unit that determines whether a parameter of the electrical signal that has passed through the electrode pair has deviated from a predetermined threshold;
A warning unit that gives a predetermined warning when the parameter deviates from the threshold;
Equipped with a,
The seat belt webbing extends from the shoulder of the occupant to the seat belt buckle via the chest, and further reaches the lap anchor from the seat belt buckle via the abdomen of the occupant,
The second electrode is installed in a region that contacts the abdomen of the occupant of the seat belt webbing,
The determination unit, through the determination of the parameter, the sensor belt device characterized that you determine if the passenger was not mounted to the case and the seat belt taking improper driving position. The sensor belt device according to claim 1 , further comprising a low-pass filter including a capacitor composed of the electrode pair.

Images