JP2024090818A - Seat belt fastening confirmation device - Google Patents

Abstract

A seat belt fastening confirmation device that is easy to install in a vehicle and is inexpensive is provided.
[Solution] The seat belt fastening confirmation device of the present invention is composed of a main unit equipped with a display device and mounted on the dashboard, and a slave unit installed under each of two or more rows of rear seats, each seat in the rear seats is provided with a seating sensor that detects the seating state of a passenger and a seat belt fastening sensor that detects the fastening state of the seat belt, and the slave unit wirelessly transmits a seat status signal for each seat to the main unit, including information on the seating state signal from the seating sensor and the seat belt fastening signal from the seat belt fastening sensor. The main unit displays the seating state on the display device, generates a warning sound if the seat belt is not fastened and the vehicle speed exceeds a certain value, and erases the warning sound and the display of the seat when the seat belt is fastened.
[Selected figure] Figure 3

Description

The present invention relates to a device that checks whether a vehicle occupant is seated and has fastened their seat belt, and issues a warning if they are not fastened.

Since September 2020, the Road Traffic Act has made it mandatory for passengers in the rear seats to wear seat belts, and requires the installation of a system that issues a warning to passengers if they are not fastened. In response to this, it is common practice to install sensors that detect the seating status of passengers and also detect fastening/unfastening of the seat belt buckles in the rear seats, sending signals indicating the seating status and fastening status of the seat belt to the dashboard of the driver's seat and warning passengers if the seat belt is not fastened.

In the case of a vehicle with only one row of rear seats, such as a sedan, the movement of the rear seats forward and backward is limited to adjusting the space under the feet. Therefore, seat status signals indicating the seating status of each seat and the fastening status of the seat belt are usually transmitted via a wire harness that runs under the floor from the seat to the dashboard. On the other hand, in the case of a vehicle with two or more rows of rear seats, such as a wagon or minivan, where the seats can be moved forward and backward significantly or folded up and stored under the floor, it is difficult to transmit the seat status signal via a wire harness. For this reason, a method of wirelessly transmitting the seat status signal from the seat to the dashboard has been disclosed (Patent Documents 1 and 2). In addition, in the case of a vehicle with multiple rows of rear seats, the seating status and the fastening status of the seat belt are usually detected and transmitted using different methods, but in such cases, the detection and information processing system as a whole becomes complicated (Patent Documents 3 and 4).

For example, Patent Document 1 describes a method in which the seating status of each seat is detected by a piezoelectric sensor and the generated voltage is transmitted via radio waves to an alarm device on the dashboard, while the fastening status of the seat belt is detected in the usual way and transmitted via cable to the dashboard, and false alarms are eliminated by comparing the two. Patent Document 2 discloses a seat belt fastening information system in which both the seating sensor and the seat belt fastening sensor are configured as RFID tags, the wireless signals are transmitted to an information processing device in the dashboard and displayed, and a carrier wave is transmitted from the information processing device to power the RFID tag.

JP 2015-51736 A JP 2009-90963 A JP 2019-69725 A JP 2020-1683 A

However, conventional seat belt fastening confirmation devices have the disadvantage that installation in a vehicle is complicated and the device and installation costs are high due to the fact that the seating signal and the seat belt fastening signal are sent to an information processing unit via separate systems (Patent Documents 1, 3-4), multiple antennas need to be installed on the floor near each seat, and the system configuration is complicated due to the use of two-way communication (Patent Documents 2-3).

(Device Configuration)
The seat belt fastening confirmation device of the present invention is composed of a main unit installed on the dashboard of the driver's seat and a slave unit installed at the bottom of each row of rear seats. The main unit is equipped with a display device.

As shown in FIG. 1, each seat in the rear seat 1 is provided with a seating sensor 2 that detects whether the seat is occupied and a seat belt fastening sensor 4 that detects whether the seat belt is fastened. The handset 10 integrates the seating signal from the seating sensor 2 and the seat belt fastening signal from the seat belt fastening sensor 4 for each seat to generate a seat status signal, and transmits the seat status signal for each seat to the main unit 20 (FIG. 2) via an individual wireless channel.

The main unit 20, on the other hand, determines whether the occupant is seated and whether the seat belt is fastened based on the seat status signal sent from the sub-unit, and displays the seat position on the display device 25 so that it can be visually identified. The main unit 20 can be installed inside or outside the dashboard, and is configured to be powered by the vehicle body.

(Outline of the sequence for checking seat belt fastening)
When the engine of the car is started and the power to the dashboard is turned on, the power to the main unit is also turned on and the displays for all the seats on the display device 25 are lit for a certain period of time to inform the driver that the main unit 20 has started operating normally. The slave unit 10 is configured to switch from a sleep state to a standby state when it detects the vehicle's inherent vibrations that accompany the engine start. When a passenger sits in a certain seat, the seating sensor 2 detects this and sends a detection signal to the slave unit 10, which then wirelessly transmits a signal to the main unit 20 indicating that the seat is occupied. The main unit 20 receives this signal and lights up the corresponding seat position on the display device 25.

When a seated passenger fastens their seat belt, the displayed light goes out. If the passenger does not fasten their seat belt and the vehicle starts moving, and the vehicle speed signal supplied from the vehicle body exceeds a certain value, the main unit 20 detects this and generates a warning sound. When the passenger fastens their seat belt in response to the warning sound, the warning sound goes off. If the passenger unfastens their seat belt when getting off or temporarily getting outside, or if the vehicle is stopped and the engine is turned off, the initial state is restored.

The seat belt fastening confirmation device of the present invention is configured as follows.
In an automobile having two or more rows of rear seats, the system comprises a main unit having a display device and mounted on a dashboard, and a sub unit installed under each of the rear seats,
A seating sensor for detecting whether a passenger is seated and a seat belt fastening sensor for detecting whether a seat belt is fastened are provided on each seat of the rear seats,
the slave unit wirelessly transmits to the main device a seat state signal for each seat, the seat state signal including information on the seating signal from the seating sensor and the seat belt fastening signal from the seat belt fastening sensor;
The main unit is configured to receive the radio signal, display the seating status for each seat on the display device, and generate a warning sound if the vehicle speed exceeds a certain value with the seat belt unfastened.
Furthermore, after the main device displays the seating state for each seat on the display device, when the seat belt is fastened, the display for that seat may be erased.

It is preferable that at least one of the seating signal and the seat belt fastening signal is transmitted to the handset via a wire.

It is preferable that the wireless system is Wi-Hi.

The handset may have a built-in battery and a vibration sensor, and may be in a sleep state while the engine of the vehicle is stopped, and may be in a standby state when the engine is started due to vibrations of the engine detected by the vibration sensor. Also, the handset may be in a sleep state after the main device erases the display on the seat.

The seat belt fastening confirmation device of the present invention converts seat occupancy information and seat belt fastening information for each seat into a signal for each seat, and transmits this fastening information for each seat collectively and wirelessly in one direction from the slave unit to the main unit for each rear seat, making it possible to simplify the configuration compared to conventional systems that use wireless. This makes it possible to provide a low-cost device that is easy to install in a vehicle.

FIG. 1 is a schematic diagram showing the arrangement of sensors on a rear seat and the arrangement of a slave unit of a seat belt fastening confirmation device according to the present invention. FIG. 2 is an external view of a main unit and a display unit of the seat belt fastening confirmation device according to the present invention. FIG. 3 is a block diagram illustrating the components of a slave unit according to the present invention. FIG. 4 is a block diagram illustrating the components of a master unit according to the present invention. FIG. 5 is a flow chart showing the sequence of operations of the seat belt fastening confirmation device according to the present invention.

The following describes in detail the embodiment of the present invention using examples.

As shown in FIG. 1, each rear seat 1 is provided with a seating sensor 2 near the surface of the seat to detect the presence of a passenger. In this embodiment, a load sensor using a pressure-sensitive film or the like is used as the seating sensor 2. FIG. 3 shows a block diagram of the components of the handset 10. An analog signal generated by the seating sensor 2 when a passenger sits down is sent to the seating signal receiving unit 12 via a wire harness and input to the handset 10. One handset 10 is installed under each rear seat, which has a row of 2 to 3 seats. The seating sensor 2 and handset 10 may be installed under the passenger seat as desired.

Meanwhile, the seat belt buckle of each seat is equipped with a seat belt fastening sensor 4 that detects whether the buckle is fastened or detached. This sensor uses a reed switch built into the buckle to magnetically detect the in and out of the tongue of the opposing seat belt. The on/off signal detected by the seat belt fastening sensor 4 is input to the seat belt fastening signal receiver 14 of the slave unit 10 via the wire harness. In this embodiment, the seating signal and the seat belt fastening signal are transmitted to the slave unit 10 via the wire harness, but the signals may also be transmitted to the slave unit 10 using a simple wireless method (e.g., RFID).

These seating signals and seat belt fastening signals are collectively encoded as seat status signals by the wireless signal generating unit 16 and wirelessly transmitted from the antenna of the handset 10 to the main unit 20 using individual channels for each seat. The seat position is identified by the channel number. In this embodiment, 2.4 GHz Wi-Hi is used as the wireless system, but other wireless systems such as FM radio, infrared communication, and Bluetooth (registered trademark) can also be used. However, using 2.4 GHz Wi-Hi is preferable in terms of power saving and communication speed.

The method of transmitting the seating signal and the seat belt fastening signal detected by the normal method to the slave unit 10 by wire and then encoding and transmitting them wirelessly as in this embodiment can improve the stability and reliability of communication compared to, for example, a method of transmitting an RFID signal directly to the dashboard (Patent Document 2). In addition, since there is no need to supply power to the RFID by radio waves and it functions with only one-way communication from the slave unit 10 to the main unit 20, it is possible to simplify the configuration of the slave unit 10 and the main unit 20.

The power for the signal processing circuit for detecting and encoding the output signals from each sensor of the slave unit 10 is supplied by a battery 18 built into the slave unit 10. While the engine of the car is stopped, the slave unit 10 is in a sleep state to minimize the power consumption of the battery 18, but when the engine is started, the built-in vibration sensor (3D acceleration sensor) 17 detects the inherent vibration of the engine, which causes the slave unit 10 to go into a standby state. When the engine is stopped and the vibration ceases, the slave unit 10 returns to a sleep state. Furthermore, as described below, if the slave unit 10 is set to return to a sleep state after all passengers have fastened their seat belts, or after the passengers have fastened their seat belts due to a warning sound, the warning sound is erased, and the seated display is erased, the power consumption of the battery can be further reduced. In addition, when the remaining charge of the battery 18 falls below a certain value, it is desirable to warn the driver by lighting or flashing the display device 25. In this embodiment, a battery is used as the power source for the slave unit 10, but this is not limited to this, and power may be supplied from under the floor by a wire harness. In this case, the slave unit 10 turns on when the vehicle power is turned on, so the vibration sensor 17 and the sleep state setting described above can be omitted.

The main unit 20 (Fig. 2) is preferably mounted inside the dashboard, but may be housed in a case and attached externally. It is powered by the vehicle power supply 30, which is turned on at the same time. The display unit 25 is connected to the main unit 20 by a connector/cable and receives a display signal. Fig. 4 is a block diagram showing the configuration of the main unit 20. The wireless signal transmitted from the handset 10 is received by the built-in antenna 21 and converted into an electrical signal by the signal receiving unit 22. The received seating status and seat belt fastening status are discriminated by the information processing unit 23, and the seat status is displayed on the display unit 25. Furthermore, the main unit 20 is adapted to receive a signal 27 from the vehicle speed sensor of the vehicle body via a wired connection, and is adapted to generate a warning sound by the warning sound generating unit 28 when the vehicle speed exceeds a certain speed, for example 40 km/h, if there is a passenger without a seat belt fastened.

The display device 25 is attached to the dashboard in a position that is easy for the driver to see. It is preferable that the display device 25 has LEDs (light emitting diodes) arranged in correspondence with the spatial positions of each seat, and indicates the status by turning them on, blinking, or off.

5 is a flow chart showing the sequence of operations of the slave unit 10 and the main unit 20. A standard sequence of operations will be described below with reference to this flow chart.
1. When the vehicle is powered on (S201), the LEDs of all the seats of the display device 25 are turned on for a certain period of time (several seconds) (S202) to inform the driver that the main device 25 has been powered on.
2. The slave unit 10 detects engine vibrations of the vehicle (S102) and transitions from the sleep state (S101) to the standby state (S103).
3. When a passenger sits down in the rear seat, the handset 10 detects this with the load sensor 2 (S104) and transmits a signal to the main unit 20 to turn on the LED at the corresponding seat position on the display device 25 (S105). The main unit 20, having received this signal, turns on the LED (S204).

4-1. When a passenger fastens a seat belt and the handset 10 detects that the seat belt is fastened (S107), it transmits a signal to the main unit 20 to indicate that the seat belt is fastened (S108), which the main unit 20 receives (S207) and turns off the lit LED on the display unit 25 (S208). If the seat belt is not fastened or is not fastened properly (S207, No), the LED for the corresponding seat remains lit.
4-2. When the driver starts the vehicle without the passenger fastening the seat belt, and the vehicle speed exceeds a certain value (for example, 40 km/h) (S205), the main unit 20 detects this signal and generates a warning sound (S206). When the passenger fastens the seat belt in response to the warning sound, the sequence proceeds to (4-1).

5. If the vehicle is stopped without stopping the engine and the passenger gets off, the handset 10 returns to the standby state (S103). Also, if the same passenger gets on again or a different passenger gets on, the sequence returns to (3).
6. When the vehicle comes to a halt and the engine is shut off (S209), the above sequence ends.

The present invention has been described based on the above examples, but the present invention is not limited thereto, and it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit of the present invention and the scope of the appended claims.

REFERENCE SIGNS LIST 1 Rear seat 2 Seat occupancy sensor 4 Seat belt fastening sensor 10 Child unit 12 Seat occupancy signal receiving unit 14 Seat belt fastening signal receiving unit 16 Wireless signal generating unit 17 Vibration sensor 18 Battery 21 Antenna 20 Main unit 22 Signal receiving unit 23 Information processing unit 25 Display unit 27 Vehicle speed sensor 28 Warning sound generating unit 30 Vehicle power supply

Claims (6)

In an automobile having two or more rows of rear seats, the system comprises a main unit having a display device and mounted on a dashboard, and a sub unit installed under each of the rear seats,
A seating sensor for detecting whether a passenger is seated and a seat belt fastening sensor for detecting whether a seat belt is fastened are provided on each seat of the rear seats,
the slave unit wirelessly transmits to the main device a seat state signal for each seat, the seat state signal including information on the seating signal from the seating sensor and the seat belt fastening signal from the seat belt fastening sensor;
The seat belt fastening confirmation device is configured so that the main unit receives the radio signal, displays the seating status on the display device for each seat, and generates a warning sound if the vehicle speed exceeds a certain value while the seat belt is not fastened. The seat belt fastening confirmation device according to claim 1, wherein at least one of the seating signal and the seat belt fastening signal is transmitted to the slave unit via a wire. The seat belt fastening confirmation device according to claim 2, wherein the wireless system is Wi-Hi. The seat belt fastening confirmation device according to claim 2 or 3, wherein the handset has a built-in battery and a vibration sensor, the handset is in a sleep state while the engine of the vehicle is stopped, and when the engine is started, the handset is in a standby state due to the vibration of the engine detected by the vibration sensor. The seat belt fastening confirmation device according to claim 4, wherein the slave unit is put into a sleep state after the main unit erases the display for the seat. The seat belt fastening confirmation device according to claim 1, in which the main device displays the seating state on the display device for each seat, and then erases the display for that seat when the seat belt is fastened.