JP2002211356A - Seat belt wearing detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt wearing detector capable of precisely detecting a wearing condition of a seat belt attached to each seat inside a vehicle. SOLUTION: A resonance circuit is formed by connecting buckles of seat belts to transmits a detection signal while sweeping a frequency form the inside of the vehicle. The transmitted detection signal is received, and the change of a receive signal generated when the detection signal becomes a resonance frequency of the resonance circuit is detected to detect wearing of the seat belt, thereby surely detecting a wearing condition of the seat belts on a plurality of seats.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seat belt wearing detecting device for detecting whether a seat belt mounted on a vehicle is properly worn.

[0002]

2. Description of the Related Art A seat belt mounted on a vehicle is provided with a buckle including a tag plate and a receiving bracket. The belt is pulled, and a tag plate attached to the belt is attached to a side of a seat. It can be easily mounted by being fitted to the provided receiving fitting.

Further, in order to detect whether or not the seat belt is worn when the vehicle is driven, a switch for detecting the wearing is provided at a connection portion between the tag plate and the receiving bracket, so that the driver can correctly operate the seat belt. A seat belt wearing detection device for detecting whether or not a user wears a seat belt has been proposed and put to practical use.

[0004] However, in such a detecting device, when the driver sits on the seat from above the seat belt with the tag plate connected to the receiving bracket, the driver does not wear the seat belt. Instead, the switch is turned on, and the wearing of the seat belt is detected.

In order to solve such a problem, there has been proposed a seat belt wearing detection device (hereinafter, referred to as a conventional example) described in Japanese Patent Application Laid-Open No. 10-181531. In the conventional example, a resonance tag is mounted in a belt of a seat belt, a loop coil is installed in a steering wheel of a vehicle, and an alternating magnetic field generated by the loop coil is disturbed by the resonance tag. Is detected by a detection circuit connected to the vehicle, and the wearing of the seat belt is detected.

[0006]

However, in the seat belt wearing detection device described in the above-mentioned conventional example,
Since the configuration uses the resonance tag attached inside the belt of the seat belt, it is not possible to detect that the buckle is correctly connected. Therefore, it is necessary to separately install a sensor for detecting the connection of the buckle.

[0007] Further, since the loop coil mounted in the steering wheel and the resonance tag mounted in the belt of the seat belt are used, it is possible to correctly detect the wearing state of the seat belt used in the driver's seat. Although possible, there is a drawback that the seat belt cannot be detected for the passenger seat or the rear seat.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. It is an object of the present invention to be able to reliably detect correct seat belt wearing with a simple configuration. Another object of the present invention is to provide a seat belt wearing detection device capable of detecting a wearing state of a seat belt in a seat other than a driver's seat.

[0009]

In order to achieve the above object, an invention according to claim 1 of the present application is a seat belt wearing detection device for detecting a wearing state of a seat belt mounted on a vehicle, A resonance circuit is formed by connecting the buckle of the seat belt, a detection signal is transmitted from the inside of the vehicle while sweeping the frequency, and the transmitted detection signal is received, and the detection signal is transmitted to the resonance circuit. It is characterized in that a change in a reception signal generated when the resonance frequency is reached is detected, and the wearing of the seat belt is detected.

According to a second aspect of the present invention, there is provided a seat belt wearing detecting device for detecting a wearing state of a seat belt mounted on a vehicle, wherein the device is attached to the seat belt and formed by connecting a buckle. A resonant circuit, transmitting and receiving antenna means, a detection signal transmitting means mounted inside the vehicle and transmitting a detection signal from the antenna means while sweeping a frequency, and the resonance circuit is formed, and the detection signal When the frequency of the resonance circuit becomes the resonance frequency of the resonance circuit, a change in a reception signal received by the antenna means is detected, and the mounting detection means detects that the resonance circuit is formed. It is characterized by having done.

The invention according to claim 3 is characterized in that the resonance circuit is an LC resonance circuit composed of a coil and a capacitor.

According to a fourth aspect of the present invention, the buckle has a structure for connecting a tag plate and a receiving member,
Of the tag plate and the bracket, one side is provided with the LC resonance circuit, and switch means for shutting off the LC resonance circuit is mounted, and the other side is provided with closing means for closing the switch means, When the tag plate and the receiving bracket are connected, the switch means is closed by the closing means to form the LC resonance circuit.

According to a fifth aspect of the present invention, the buckle has a structure for connecting a tag plate and a receiving member,
The LC resonance circuit is mounted on the receiving bracket side, and when the tag plate is connected to the receiving bracket, the tag plate is inserted to change the inductance of a coil constituting the LC circuit, thereby causing the LC resonance circuit to change. It is characterized in that the resonance frequency of the circuit is changed and the changed resonance frequency is detected to detect the seat belt wearing.

According to a sixth aspect of the present invention, the buckle has a structure for connecting a tag plate and a receiving member,
When the coil is mounted on one side of the tag plate and the receiving bracket, and the capacitor is mounted on the other side, when the tag plate and the buckle body are connected,
A coil and a capacitor are connected to form the LC resonance circuit.

According to a seventh aspect of the present invention, when the child seat is fixed using the seat belt, an auxiliary buckle is provided between the tag plate and a receiving member, and the auxiliary buckle is connected to the tag plate. An auxiliary circuit for forming a resonance circuit having a frequency different from the frequency of the resonance circuit formed when directly connected to the receiving fitting is provided.

According to an eighth aspect of the present invention, the resonance circuit is mounted on two or more seat belts among seat belts mounted on each seat of the vehicle, and the resonance circuit mounted on each seat belt is It is characterized in that the resonance frequencies are set differently.

According to a ninth aspect of the present invention, an auxiliary resonance circuit having a resonance frequency different from a resonance circuit formed when the buckle is connected is mounted in the tag plate of the seat belt. When the resonance frequency of the auxiliary resonance circuit is not detected, the detection unit determines that the seat belt is in a state of being caught by a vehicle door.

According to a tenth aspect of the present invention, there is provided a seatbelt mounting detecting device for detecting a mounted state of a seatbelt mounted on a vehicle, wherein the childbelt is mounted on a seat using the seatbelt. A seat clip is fixed at a predetermined position, and a fixing clip having a resonance circuit mounted therein, and the seat belt is arranged near the fixing clip mounting position of the seat belt, and when the seat belt comes close to the resonance circuit, the resonance Resonance frequency changing means for changing the resonance frequency of the circuit, antenna means for transmission and reception,
A detection signal transmitting unit mounted inside the vehicle and transmitting a detection signal from the antenna unit while sweeping a frequency, and a resonance frequency of the resonance circuit after the frequency of the detection signal is changed by the resonance frequency changing unit. And a mounting detection unit that detects a change in a reception signal received by the antenna unit and detects that the resonance circuit has approached the resonance frequency changing unit. And

According to the eleventh aspect, the antenna means is a loop antenna, and the loop antenna is
It is mounted inside the steering wheel of the vehicle or inside the ceiling of the vehicle.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of the seatbelt wearing detection device according to the first embodiment of the present invention. As shown in FIG. 1, the seatbelt wearing detection device 1 includes a tag (resonance circuit) 2 formed when a buckle mounted on a seatbelt is connected, and an antenna magnetically coupled to the tag 2. Coil (antenna means) 3
And a frequency sweep circuit (detection signal transmitting means) 4 for applying an AC voltage to the antenna coil 3 and sweeping the frequency of the AC voltage within a predetermined frequency band.
And Further, a resonance frequency detection circuit (attachment detection means) 5 for detecting a voltage generated in the antenna coil 3 and detecting a resonance frequency of the tag 2 is provided.

The frequency sweep circuit 4 outputs a triangular wave-shaped detection signal while changing the frequency, and a V for controlling the output level of the triangular wave generator 11.
A CO (voltage control controller) 12 can output a detection signal to the antenna coil 3 while sweeping the frequency in a predetermined band.

The resonance frequency detection circuit 5 includes a detector 13 for detecting a change in a voltage signal generated in the antenna coil 3;
A preamplifier 14 for amplifying an output signal of the detector 13;
A BPF (Band Pass Filter) 15 for extracting a signal of a predetermined frequency from the signal amplified by the preamplifier 14
And a tone detector 16 for removing noise;
A microcomputer 17 that determines the state of the tag 2 (whether or not the tag 2 is formed) based on the frequency of the detection signal when the change in the voltage signal is detected.

FIG. 2 is an explanatory view schematically showing how the buckle 22 mounted on the seatbelt is connected. As shown in FIG. 2, the buckle 22 has a receiving member 24 and the receiving member 24. And a detachable tag plate 23.

The bracket 24 is attached to the side of the seat of the vehicle, and a loop coil L1 is sewn into a belt portion 24a of the bracket 24. Further, a capacitor C1 and a connection switch (switch means) SW1 are mounted on the metal part 24b of the receiving metal 24. When the buckle 22 is connected (ie, when the tag plate 23 and the receiving metal fitting 24 are fitted), the connection switch SW1 is closed and the tag (LC resonance circuit) 2 formed by the capacitor C1 and the loop coil L1 is closed. To form

As shown in FIG. 3, the loop coil L1 has a structure in which an electric wire is wound in a rectangular spiral shape, and has a plurality of connection points (three connection points T1 to T3 in the figure. But not limited to). The inductance of the loop coil L1 can be adjusted by appropriately setting the connection point with the connection point T0 on the capacitor C1 side.

The tag plate 23 is, as shown in FIG.
A metal plate 23a having a square shape, and by inserting the metal plate 23a into the metal fitting 24,
The buckle 22 can be connected and a seat belt can be worn. Further, when the metal plate 23a is inserted into the metal fitting 24, the connection switch SW1 is closed.

The above-described tag 2 is installed on each of the seat belts of the respective seats mounted on the vehicle. Further, the connection point of the loop coil L1 shown in FIG. T1 to T3) are set to be different. Therefore, the resonance frequency of the tag 2 mounted on the seat belt differs for each seat.

Next, the operation of the embodiment constructed as described above will be described. The occupants sitting in each seat of the vehicle,
After sitting on the seat, the tag plate 23 shown in FIG. 2 is attached to the receiving fitting 24, and the connection switch SW1 on the receiving fitting 24 side is closed by the metal plate 23a, and the tag (L
C resonance circuit) 2 is formed. In this state, when the triangular wave generator 11 shown in FIG. 1 outputs a detection signal having a triangular waveform periodic waveform, the detection signal is applied to the antenna coil 3, and the frequency of the detection signal is provided near the antenna coil 3. Generates a changing magnetic field.

Further, when the frequency of the detection signal is swept (swept) in a predetermined frequency band, when the frequency of the detection signal matches (or approaches) the resonance frequency of the tag 2, the tag 2 and the antenna coil Due to magnetic coupling with the antenna coil 3, a large change occurs in the voltage value generated in the antenna coil 3.

In the detector 13 of the resonance frequency detection circuit 5,
A signal when a change in the voltage value occurs in the antenna coil 3 is detected. The detected signal is amplified by a preamplifier 14 and supplied to a microcomputer 17 via a BPF 15 and a tone detector 16.

Then, the microcomputer 17 detects the frequency of the detected signal, and based on the detected frequency, can detect that the tag 2 is formed, and confirms that the seat belt 21 is properly worn. You can check. When the tag plate 23 is not mounted in the receiving bracket 24, the connection switch SW1 is not closed, so that the tag 2 is not formed and the resonance frequency detection circuit 5
Cannot detect the presence of the tag 2. In this case, the microcomputer 17 determines that the seat belt 21 is not fastened, and can notify the occupant by a warning lamp (not shown) or the like.

Further, since the resonance frequency of the tag 2 is set to be different for each seat belt attached to each seat in the vehicle, a plurality of seats are swept by sweeping the detection signal within a predetermined frequency band. Out of the belt
It is possible to recognize all seat belts that are properly worn and seat belts that are not properly worn.

As described above, in the seat belt wearing detection device 1 according to the present embodiment, the tag (LC resonance circuit) 2 formed when the buckle 22 (the tag plate 23 and the receiving metal fitting 24) is connected to the seat is attached to the seat. A detection signal is output while being mounted on a belt and the frequency is swept in a predetermined frequency band. When the frequency of the detection signal reaches the resonance frequency of the tag 2, a voltage change occurring in the antenna coil 3 is detected, Is formed.

Therefore, for example, when the occupant sits on the seat belt 21 to which the buckle 22 is connected, even if the tag 2 is formed, the magnetic force between the tag 2 and the antenna coil 3 is maintained. The wearing of the seatbelt is not detected because it is shielded. Thereby, it can be reliably detected that the seat belt 21 is properly worn. Further, it is possible to detect the wearing state of not only the driver's seat but also the seat belts 21 of all the seats in the vehicle.

FIG. 4 is an explanatory view showing the configuration of a first modification of the buckle 22 used in the above-described embodiment. As shown in the figure, the buckle 22 of the modification has a loop coil L1 attached to a belt portion 24a of a receiving bracket 24, and a capacitor C1 attached to a tag plate 23 side. And the tag plate 23
When the metal plate 23a is mounted in the metal fitting 24, the capacitor C1 and the loop coil L1 are connected to form the tag 2.

The buckle 2 constructed as described above
Even when the tag 2 is used, the tag (LC resonance circuit) 2 is formed by the connection of the buckle 22, so that the same effect as in the above-described embodiment can be obtained.

FIG. 5 is an explanatory view showing the configuration of the buckle 22 according to a second modification. As shown in the figure, the buckle 22 of the modified example has a metal part 24 b of a receiving metal 24,
The loop coil L1 is mounted, and the capacitor C1 is mounted on the tag plate 23 side. When the metal plate 23a of the tag plate 23 is mounted in the metal fitting 24, the capacitor C1 and the loop coil L1 are connected to form the tag 2.

The buckle 2 constructed as described above
2, the same effect as in the above-described embodiment can be obtained.

FIG. 6 is an explanatory diagram showing the configuration of the buckle 22 according to a third modification. As shown in the figure, in the modification, a loop coil L1 is disposed so as to wind around a metal part 24b of a receiving metal part 24, and the loop coil L
A capacitor (not shown) connected to 1 is provided. When the metal plate 23a of the tag plate 23 is attached to the receiving metal fitting 24, the metal plate 2
Due to 3a, the inductance of the loop coil L1 changes, and the resonance frequency of the tag (LC resonance circuit) 2 formed by the loop coil L1 and the capacitor changes.

The resonance frequency detecting circuit 5 shown in FIG. 1 detects that the buckle 22 is connected by detecting the changed resonance frequency. And even if it uses the buckle 22 comprised in this way, the same effect as the above-mentioned embodiment can be obtained. Further, there is no need to provide an electrical contact on the buckle 22.

In this modification, the tag plate 23
Is used to change the inductance of the loop coil L1, but it is also possible to change the resonance frequency of the tag 2 by changing the capacitance of the capacitor by inserting materials having different dielectric constants. It is possible.

FIG. 7 is an explanatory view showing the configuration of the fourth modification of the buckle 22. As shown in FIG. In this modification, when attaching a child seat to a seat using a seat belt,
The resonance frequency of the tag 2 is set to be different from that during normal use, and the mounted state of the child seat is detected.

As shown in FIG.
A dummy buckle (auxiliary buckle) 25 is interposed between the tag plate 23 and the receiving fitting 24.

The dummy buckle 25 is tied to a child seat (not shown) using a chain or the like, and has a receiving metal part 25a for mounting the tag plate 23 and a plate part 25b for mounting on the receiving metal 24. An auxiliary capacitor (auxiliary resonance circuit) C2 is mounted inside the receiving metal part 25a. Then, the dummy buckle 2 is placed between the tag plate 23 and the receiving bracket 24.
5, the capacitance (capacitance) due to the parallel connection of the capacitors C1 and C2
Is obtained, the resonance frequency of the tag 2 formed when the tag 2 is connected to the loop coil L1 has a value different from that when the dummy buckle 25 is not used.

Thus, a unique resonance frequency can be set when the child seat is mounted, and it is possible to detect which seat in the vehicle has the child seat mounted. Further, by linking this detection signal with an airbag detonator (not shown), the operation of the airbag in the seat on which the child seat is mounted can be controlled.

That is, in a seat where it is detected that the child seat is attached, the safety at the time of driving can be further improved by controlling so that the airbag is not detonated.

FIG. 8 is an explanatory view showing the configuration of a fifth modification of the buckle 22. As shown in FIG. In this modified example, the fourth
This is different from the modified example in that an auxiliary capacitor C2 and an auxiliary loop coil L2 are installed in the receiving metal part 25a of the dummy buckle 25. That is, the dummy buckle 2 is placed between the tag plate 23 and the receiving member 24.
5, the parallel connection of the capacitors C1 and C2 and the parallel connection of the loop coils L1 and L2 are formed, and the tag 2 is formed by these.

Accordingly, since the resonance frequency can be changed as compared with when the dummy buckle 25 is not used, it is possible to reliably detect that the child seat is mounted.

FIG. 9 is an explanatory view showing the configuration of a sixth modification of the buckle 22. As shown in FIG. As shown in the drawing, in the modification, an auxiliary tag 31 constituted by an LC resonance circuit having a resonance frequency different from that of the tag 2 described above is provided on a tag plate 23 constituting the buckle 22. In the microcomputer 17 shown in FIG. 1, the auxiliary tag 31 and the antenna coil 3
When the magnetic connection is detected, and the magnetic connection is not detected, the auxiliary tag 31, that is, the tag plate 23 is sandwiched between the doors of the vehicle and protrudes outside the door. And outputs an alarm signal.

According to such a configuration, it is possible to detect the correct wearing of the seat belt with high accuracy, and to notify the occupant when the tag plate 23 is caught in the door. .

FIG. 10 is an explanatory view showing a seat belt wearing detection device according to a second embodiment of the present invention. In the present embodiment, when the child seat 26 is fixed using the seat belt 21 of the seat, the tag 2 is attached to the fixing clip 27 attached to the belt portion of the seat belt 21 so that the child seat 26 is correctly mounted. Detect whether or not.

That is, as shown in FIG. 10, the child seat 26 is attached to the seat in an accurate state in advance, and at this time, the mark 28 is recorded at the position where the fixing clip 27 of the seat belt 21 is attached using magic or the like. I do. Further, a conductive sheet (or a member made of a material capable of changing the capacitance of the capacitor and the inductance of the coil) is attached to a portion of the seat belt 21 where the mark 28 is written.

The fixing clip 27 is a metal plate 27
a and an L-shaped fitting 27b.
With the seat belt 21 locked to the metal plate 2
The child seat 26 can be stably attached to the seat belt 21 by fixing the fixing member 7a to the locking portion 26a formed on the side of the child seat 26.

Then, the tag 2 composed of a capacitor and a loop coil is installed on the fixing clip 27, and when the fixing clip 27 is attached to the portion where the mark 28 is written, the tag is attached by a conductive sheet. 1 changes, the resonance frequency after this change is
Is detected by the resonance frequency detection circuit 5 shown in FIG.
It can be detected that the child seat 26 is correctly mounted.

As described above, the seat belt wearing detecting device 1 of the present invention has been described based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each part may be any having the same function. It can be replaced with the configuration of

For example, in the above embodiment, the detection signal is output using the triangular wave generator 11, but the present invention is not limited to this, and other periodic waveforms may be used. it can.

[0057]

As described above, in the seatbelt wearing detection device according to the present invention, the resonance circuit formed when the buckle is connected is installed in each seatbelt of the vehicle, and each seatbelt is installed. The resonance frequency of the resonance circuit is set to be different every time. Therefore, by detecting these resonance frequencies, it is possible to reliably detect whether or not the seat belt of each seat is properly worn.

When attaching the child seat,
By placing the dummy buckle between the tag plate and the receiving fitting, the resonance frequency of the resonance circuit is set to be different, so that the mounting state of the child seat can be reliably detected.

Further, since the wearing state of the seat belt can be wirelessly detected, the wiring can be easily arranged.

Further, a resonance circuit is mounted on a fixing clip for fixing the child seat to the seat belt, and the resonance frequency of the resonance circuit is changed by resonance frequency changing means (conductive sheet or the like) mounted on the seat belt. However, if the configuration is such that the mounting of the child seat is detected by detecting the changed resonance frequency, the mounting of the child seat can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a seatbelt wearing detection device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a buckle used in the seatbelt wearing detection device according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a configuration of a buckle according to a first modified example of the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a second modification of the buckle according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a configuration of a third modification of the buckle according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a configuration of a fourth modification of the buckle according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a configuration of a fifth modification of the buckle according to the embodiment of the present invention.

FIG. 8 is an explanatory view showing a configuration of a sixth modification of the buckle according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a state in which an auxiliary tag is attached to a tag plate.

FIG. 10 is an explanatory view showing a state in which a tag is attached to a child seat fixing clip according to the second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 seat belt wearing detection device 2 tag 3 antenna coil 4 frequency sweep circuit 5 resonance frequency detection circuit 11 triangular wave generator 12 VCO (voltage control controller) 13 detector 14 preamplifier 15 BPF (bandpass filter) 16 tone detector 17 microcomputer 21 Seat belt 22 Buckle 23 Tag plate 23a Metal plate 24 Bracket 24a Belt portion 24b Bracket portion 25 Dummy buckle 25a Bracket portion 25b Plate portion 26 Child seat 26a Locking portion 27 Fixing clip 27a Metal plate 27b L-shaped bracket 28 Mark 31 Auxiliary Tag SW1 Connection switch C1, C2 Capacitor L1, L2 Loop coil

Claims (11)

[Claims] 1. A seat belt wearing detecting device for detecting a wearing state of a seat belt mounted on a vehicle, wherein a resonance circuit is formed by connecting a buckle of the seat belt, and a frequency is controlled from inside the vehicle. Transmitting a detection signal while sweeping, and receiving the transmitted detection signal, detecting a change in a reception signal generated when the detection signal reaches the resonance frequency of the resonance circuit, and An attachment detection device for a seat belt, wherein the attachment detection device detects attachment of the seat belt. 2. A seat belt wearing detection device for detecting a wearing state of a seat belt mounted on a vehicle, comprising: a resonance circuit attached to the seat belt and formed by connecting a buckle; Antenna means, mounted inside the vehicle, and a detection signal transmitting means for transmitting a detection signal from the antenna means while sweeping the frequency, the resonance circuit is formed, and the frequency of the detection signal is the resonance circuit A seat detecting means for detecting a change in a reception signal received by the antenna means when the resonance frequency is reached, and detecting that the resonance circuit is formed. Belt attachment detection device. 3. The seat belt wearing detection device according to claim 1, wherein the resonance circuit is an LC resonance circuit including a coil and a capacitor. 4. The buckle has a structure for connecting a tag plate and a receiving member, wherein the LC resonance circuit is provided on one side of the tag plate and the receiving member, and
A switch means for interrupting the C resonance circuit is mounted, and a closing means for closing the switch means is mounted on the other side, and when the tag plate and the receiving bracket are connected, the switch means is closed by the closing means. The seat belt wearing detection device according to claim 3, wherein the LC resonance circuit is formed by closing the circuit. 5. The buckle has a structure for connecting a tag plate and a receiving member, and the buckle has the LC on the receiving member side.
When a resonance circuit is mounted and the tag plate is connected to the receiving bracket, the tag plate is inserted to change the inductance of the coil constituting the LC circuit, thereby changing the resonance frequency of the LC resonance circuit. The seat belt wearing detecting device according to claim 3, wherein the changed resonance frequency is detected to detect seat belt wearing. 6. The buckle has a structure for connecting a tag plate and a receiving member, and the coil is mounted on one side of the tag plate and the receiving member, and the capacitor is mounted on the other side. 4. The seat belt wearing detecting device according to claim 3, wherein when the tag plate and the buckle body are connected, the coil and the capacitor are connected to form the LC resonance circuit. 7. An auxiliary buckle is provided between the tag plate and a receiving bracket when fixing the child seat using the seat belt, and the auxiliary buckle directly connects the tag plate and the receiving bracket. 7. The seat belt wearing detection device according to claim 6, further comprising an auxiliary circuit for forming a resonance circuit having a frequency different from the frequency of the resonance circuit formed at that time. 8. The resonance circuit is mounted on two or more seat belts among seat belts mounted on each seat of the vehicle, and the resonance circuits mounted on the respective seat belts have different resonance frequencies. The seat belt wearing detection device according to any one of claims 1 to 7, wherein the setting is set. 9. In the tag plate of the seat belt,
An auxiliary resonance circuit having a resonance frequency different from a resonance circuit formed when the buckle is connected is mounted, and the mounting detecting unit detects the seat belt when the resonance frequency of the auxiliary resonance circuit is not detected. Is determined to be in a state sandwiched between vehicle doors.
A seat belt wearing detection device according to claim 8. 10. A seat belt wearing detection device for detecting a wearing state of a seat belt mounted on a vehicle, the seat belt being fixed at a predetermined position when a child seat is attached to a seat using the seat belt. A fixing clip having a resonance circuit mounted therein, and a seat belt, which is disposed near the fixing clip mounting position, and changes the resonance frequency of the resonance circuit when approaching the resonance circuit. Resonance frequency changing means, transmitting and receiving antenna means, detection signal transmitting means mounted inside the vehicle and transmitting a detection signal from the antenna means while sweeping the frequency, and the frequency of the detection signal changes the resonance frequency. When the resonance frequency of the resonance circuit reaches the resonance frequency after the change by the means, the signal is received by the antenna means. That detects a change of the received signal, the attachment detection device for a seat belt in which the resonant circuit is characterized in that anda mounting detecting means for detecting that approaches the resonant frequency changing means. 11. The antenna according to claim 1, wherein the antenna means is a loop antenna, and the loop antenna is mounted inside a steering wheel of the vehicle or inside a ceiling of the vehicle. The seatbelt wearing detection device according to the paragraph.