JP5750399B2 - 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.

As attention technology occupant, for example, Patent Document 1, the driver in a case when it is incorrect status an alarm such as a driver state determination device is described in operation. 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, a determination of whether an alarm, since is performed by using the camera, do not give Lazar such a large-scale construction. Currently, compact vehicle Ri tended increasingly advances, mechanism for alarm or the like on the driver, are also those of a more simple configuration is desired.

  In view of such a problem, the present invention provides a sensor belt that gives a warning when an occupant takes an inappropriate driving posture or when a seat belt is not worn, and is improved in accuracy. The object is to provide a device.

  In order to solve the above problems, a typical configuration of a sensor belt device according to the present invention includes a first electrode provided on a steering wheel or a seat of a vehicle and a belt-like resistance heating element, which is provided on a seat belt webbing. A first electrode and a second electrode constituting an electrode pair, a heater control unit for supplying power to the second electrode to generate heat, a motor retractor for winding up the seat belt webbing, and the motor retractor for seat belt webbing A transmitting unit that transmits an electric signal having a predetermined frequency to the electrode pair immediately after winding or a determining unit that determines whether or not the parameter of the electric signal that has passed through the electrode pair has deviated from a predetermined threshold value And a warning unit that performs a predetermined warning when the parameter deviates from the threshold value.

  In the sensor belt device, when the occupant wears the seat belt webbing and grips the steering wheel, or when the occupant sits on the seat and wears the seat belt webbing, the occupant is interposed between the electrode pair constituted by these. It will be. 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 particular, the sensor belt device includes a motor retractor, and the transmitter transmits an electrical signal when the motor retractor winds up the seat belt webbing or immediately after the seat belt webbing. That is, the above-described detection is performed when the degree of adhesion between the seat belt webbing and the occupant is increased. When electrically detecting the occupant's posture, etc., the contact area between the occupant and the second electrode has an effect, but with the sensor belt device, by increasing the degree of contact between the seat belt webbing and the occupant, The posture and the like can be determined with higher accuracy.

  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 first electrode is provided on the steering wheel, and includes a right-hand electrode provided on the right side in the vehicle width direction of the steering wheel, and a left-hand electrode provided on the left side in the vehicle width direction of the steering wheel. A right-hand determination unit that is determined downstream of the right-hand electrode and a left-hand determination unit that is determined downstream of the left-hand electrode may be included. According to this configuration, it can be more accurately determined whether or not the occupant is performing a one-handed operation.

  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, it is possible to provide a sensor belt device with improved accuracy that warns when an occupant takes an inappropriate driving posture or when a seat belt is not worn. Is possible.

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. FIG. 4 is a diagram illustrating a change in an apparent capacitance C of an occupant in FIG. 3. 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. 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. A sensor belt device (hereinafter referred to as a sensor belt 100) determines whether or not the occupant 102 is wearing the seat belt 104 correctly 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 (see 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 base side of the webbing 106 is housed in the motor retractor 150. The motor retractor 150 is an electric retractor that includes a motor 152. In the present embodiment, the motor retractor 150 is operated to apply tension to the webbing 106, so that the degree of adhesion of the second electrode 112 to the occupant 102 can be increased.

  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 control unit 122 of the sensor belt 100 starts the operation of the motor retractor 150 to increase the degree of adhesion between the second electrode 112 and the occupant 102. When the motor retractor 150 is winding the webbing 106, that is, when the degree of adhesion between the webbing 150 and the occupant is increased, an electrical signal having a predetermined frequency is transmitted from the transmitter 124. The electrical signal may be transmitted when the degree of close contact between the webbing 150 and the occupant is increased, for example, at the same time as or after the winding of the webbing 106 by the motor retractor 150 is completed. The LPF 1 described above exists at the destination of the electric signal. In the present embodiment, the driving posture of the occupant 102 is determined by detecting a parameter (voltage value in the present embodiment) of the electrical signal that has passed through the LPF 1.

  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.

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 the configuration described above, the sensor belt 100 can prompt the occupant 102 to board in the correct posture / state. In particular, in the present embodiment, the degree of adhesion between the second electrode 112 and the occupant 102 is increased by the motor retractor 150. FIG. 6 is a diagram illustrating a change in the apparent capacitance C of the occupant 102 of FIG. As illustrated in FIG. 6, when the motor retractor 150 is operated in addition to the mounting of the seat belt (webbing 106), the capacitance C increases. Thereby, the amplitude (V) illustrated in FIG. 5A is further increased, and the range in which the threshold Vi can be set is widened. Moreover, since the contact state between the second electrode 112 and the occupant 102 is stabilized by increasing the tension with the motor retractor 150, the posture and state of the occupant 102 can be determined with higher accuracy.

(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.

(First modification)
FIG. 9 is a modification of the sensor belt device of FIG. The sensor belt device illustrated in FIG. 9 (hereinafter referred to as sensor belt 200) is different from the sensor belt 100 in terms of the configuration of the first electrode 202 and the determination unit 204.

  As illustrated in FIG. 9A, the first electrode 202 of the sensor belt 200 is provided on the steering wheel 108 on the right side in the vehicle width direction 202a and on the left side in the vehicle width direction. It is comprised with the electrode 202b for left hands. 9B, the determination unit 204 is provided with a right-hand determination unit 204a downstream of the right-hand electrode 202a and a left-hand determination unit 204b downstream of the left-hand electrode 202b. . According to this configuration, the grip state of the occupant 102 with the right hand and the grip state of the left hand can be determined independently. Therefore, it is possible to more accurately determine whether or not the occupant 102 is performing a one-handed operation.

(Second modification)
FIG. 10 is a modification of the sensor belt device of FIG. In the sensor belt device illustrated in FIG. 10 (hereinafter referred to as sensor belt 300), the installation position of the first electrode 302 is different from that of the sensor belt 100 in FIG. The first electrode 302 of the sensor belt 300 is installed on the seat back 144 that is easily contacted by the occupant 102 (see FIG. 1) among the 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 ... resistance, R3 ... feedback resistor, W4 ... pulse signal, e ... AC signal source, 100, 200, 300 ... sensor belt, 102 Occupant, 104, seat belt, 106, webbing, 108, steering wheel, 110, 202, 302, first electrode, 112, second electrode, 114, grip part, 116, resistance heating element, 118a, 118b, electrode wire , 120 ... protection member, 122 ... control part, 124 ... transmission part, 126 ... determination part, 128 ... ECU, 130 ... warning part, 132 ... heater control part, 134a and 134b ... switching element, 136 ... ECU, 138a and 138b ... Connector, 140 ... Seat cushion, DESCRIPTION OF SYMBOLS 142 ... Seat, 144 ... Seat back, 150 ... Motor retractor, 152 ... Motor, 160 ... CR circuit, 170 ... Automatic balance bridge, 202a ... Right hand electrode, 202b ... Left hand electrode, 204a ... Right hand electrode, 204b ... Left hand Electrode

Claims (3)

A first electrode provided on a steering wheel of the vehicle;
A belt-like resistance heating element, which is provided in a region of the seat belt webbing that is in contact with the vicinity of the abdomen of the occupant and constitutes an electrode pair with the first electrode;
A heater controller for supplying power to the second electrode to generate heat;
A motor retractor for winding the seat belt webbing;
A transmitter for transmitting an electric signal of a predetermined frequency to the electrode pair when the motor retractor is winding the seat belt webbing or immediately after winding;
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 sensor belt device comprising: a warning unit that performs a predetermined warning when it is determined that the parameter deviates from the threshold value and the occupant is in a dangerous state . The first electrode may include a right-hand electrode provided among vehicle width direction right of the steering wheel, and a left hand electrode provided among vehicle width direction left of the steering wheel,
2. The sensor according to claim 1, wherein the determination unit includes the determination unit for the right hand that is determined downstream of the electrode for the right hand, and the determination unit for the left hand that is determined downstream of the electrode for the left hand. Belt device.   The sensor belt device according to claim 1, further comprising a low-pass filter including a capacitor composed of the electrode pair.

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