JP4297560B2 - Seat belt device - Google Patents

Description

[0001]
[Industrial application fields]
TECHNICAL FIELD The present invention relates to a vehicle seat belt device that restrains an occupant to a seat for safety of the occupant, and more particularly to a vehicle seat belt device, and more particularly, a seat that uses an electromechanical power source such as an electric motor. The present invention relates to a seat belt device using a belt winding device.
[0002]
[Prior art]
Conventionally, a device that measures the distance between obstacles with a radar, etc., predicts a collision based on the distance, changes the tension of the seat belt, and gives an alarm or a tension increase is, for example, Japanese Utility Model Laid-Open No. 6-71333. It is proposed in the issue. According to such an apparatus, it functions effectively when an obstacle is detected, so that it is expected to be effective in ensuring the safety of passengers.
[0003]
[Problems to be solved by the invention]
However, looking at the number of vehicle accidents by location, there are many occurrences on curved roads or intersections with poor visibility. On curved roads with poor visibility, there are many cases where the opponent vehicle suddenly appears over the center line and a collision occurs. At intersections, there are many cases of collision with vehicles that suddenly cross the front of the vehicle.
[0004]
Therefore, even if an obstacle can be detected by the radar, it will be detected immediately before the collision, and in an apparatus that can electrically change the tension of the seat belt, since the time that can be moved before the collision is short, its effect is reduced. There is a risk that it will not be able to fully demonstrate.
[0005]
Therefore, an object of the present invention is to provide a seat belt device that can change the tension of the seat belt in accordance with the danger level of the region (section) where the host vehicle is traveling or the travel point (location).
[0006]
Another object of the present invention is to provide a seat belt device that alerts the occupant when entering or traveling to a high-risk area (area) or travel point (location). .
[0007]
Another object of the present invention is to provide a seat belt device that is linked to a navigation system that guides driving of a vehicle.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a seat belt device of the present invention includes a seat belt that restrains an occupant to a seat, a belt winding device that winds and pulls out the seat belt by an electric motor, and data including at least road map information. A base, and a current travel position of the host vehicle on the road map is detected, and a distance between the road danger point in the traveling direction of the host vehicle and the current travel position on the road map or the current Seat belt control means for adjusting the tension of the seat belt by controlling the electric motor in accordance with a discrimination output signal from a travel guidance device for discriminating the arrival time from the travel position to the danger point.
[0009]
Preferably, the dangerous point includes a curve, an intersection, a frequent accident point, and a construction restriction point.
[0010]
Preferably, the seat belt control means is configured such that the distance between the dangerous point and the current traveling position or the arrival time from the current traveling position to the dangerous point is equal to or shorter than a first reference distance or a reference time. In this case, alert the occupant by changing the tension of the seat belt.
[0011]
Preferably, the seat belt control means has a second reference whose distance between the dangerous point and the current traveling position or an arrival time from the current traveling position to the dangerous point is smaller than the first reference distance. When the distance is less than the distance or less than the second reference time which is smaller than the first reference time, the tension of the seat belt is set to be large.
[0012]
Preferably, the travel position detection means includes at least one of a GPS device, a D-GPS device, an inertial navigation device, road-to-vehicle communication (VICS), and a navigation device.
[0013]
Preferably, the seat belt control means increases the tension of the seat belt when a curved road is detected in the traveling direction of the host vehicle.
[0014]
Preferably, when the host vehicle approaches a dangerous point when the host vehicle speed is equal to or higher than a predetermined value by the speed detection unit that detects the host vehicle speed, the seat belt control device intermittently changes the tension of the seat belt. And alert the passengers.
[0015]
Further, the seat belt control system of the present invention includes a belt winding device that winds and pulls out a seat belt by an electric motor, a database including at least road map information, and a current state of the vehicle on the road map. Travel position detection means for detecting the travel position of the vehicle, and the distance between the current dangerous position on the road map in the traveling direction of the host vehicle and the current travel position, or the arrival time from the current travel position to the dangerous point And a seat belt control means for controlling the electric motor according to the discrimination result to adjust the tension of the seat belt.
[0016]
With such a configuration, the position of the host vehicle is detected, and the seat belt tension is increased in advance before a dangerous point such as a curve or an intersection. Even if a collision occurs, the slack of the seat belt can be removed before the collision, and effective occupant restraint can be performed. Further, since the probability of an accident is high at a carp or an intersection, if the speed of the host vehicle is higher than a predetermined value before the vehicle is acquired, the tension of the seat belt is intermittently changed to give an alarm.
[0017]
Embodiment
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a seat belt device. The seat belt device is disposed on the waist by an electric winding device 100 that winds a belt 302 that restrains the occupant to the seat 301 with an electric motor, a through anchor 303 that folds the belt 302 in the vicinity of the shoulder of the occupant, and a belt that is inserted. A tongue plate 305 that engages with the buckle 304, an anchor 306 that fixes the end of the belt 302 to the vehicle body, a switch 307 built in the buckle, a control unit 200 (not shown), and the like.
[0018]
FIG. 2 is an explanatory diagram schematically illustrating the configuration of the electric winding device 100. In FIG. 1, the taking apparatus 100 includes a frame 101. The frame 101 is provided with a reel 103 for winding a belt (not shown) and a reel shaft 103a that is coupled to the reel 103 and serves as a central axis of reel rotation. A known seat belt lock mechanism 102 that locks the withdrawal of the seat belt when a predetermined deceleration acts on the vehicle or when the belt is pulled out at a predetermined acceleration is fixed to the right end portion of the reel shaft 103a. . A pretensioner 104, a pulley 105, and a potentiometer 111 are provided at the left end of the reel shaft 103a. The pretensioner 104 is operated by an output of a collision detector (not shown), rotates the reel shaft 103a in the belt winding direction, forcibly winds the belt, and restrains the occupant to the seat. The pretensioner 104 is, for example, an explosive pretensioner, and includes a gas generator, a cylinder that seals gas generated from the gas generator, a piston that moves in the cylinder by gas pressure, and movement of the piston via a clutch mechanism. And a transmission mechanism for converting the rotational movement of the reel shaft 103a. The pulley 105 fixed to the reel shaft 103 a is connected to the pulley 106 fixed to the shaft of the DC motor 110 via a power transmission belt 107. A predetermined number of external teeth are formed on the outer circumferences of the pulleys 105 and 106, and a predetermined number of internal teeth are also formed on the inner circumference of the belt 107. The teeth of the pulley 105 for the reel shaft, the pulley 106 for the motor, and the belt 107 mesh with each other without excess and deficiency, and the rotation of the motor 110 is transmitted to the reel shaft 103a. The motor 110 is fixed to the frame 101 at at least two points, and operates according to the output of the control unit 200.
[0019]
The potentiometer 111 provided at the leftmost end of the reel shaft 103a is a known one, and is configured by a resistor to which a constant voltage is applied to both ends and a slider that is interlocked with the rotation of the reel shaft 103a. Then, a voltage value corresponding to the rotation amount from the reel shaft 103a reference position is output to the control unit 200.
[0020]
FIG. 3 is a block diagram illustrating a schematic configuration of the control unit 200 and the navigation system. As shown in the figure, the control unit 200 is configured by a microcomputer system. The CPU 201 loads a control program and data stored in the ROM 202 into the work area of the RAM 203 and executes various programs described later to control operations such as normal rotation, reverse rotation, and stop of the motor 110. The output voltage of the potentiometer 111 described above is A / D converted at a predetermined cycle by the input interface 204. The input interface 204 has a built-in CPU and monitors the converted output voltage data. For example, when the previous value and the current value of the output voltage data are different, the rotation state of the shaft 103a is determined, and the flag “shaft rotation” is set in the flag area (flag register) of the RAM 203 by the DMA operation. If there is no difference (including the case where the difference is slight), a flag “shaft stop” is set. Depending on whether the difference between the previous value and the current value of the output voltage data is positive or negative, the belt "drawing" (shaft 103a reverse) flag or "winding" (shaft 103a forward) flag is set in the flag area of the RAM 203. Set. Further, the output voltage data is written in the rotation amount area of the shaft 103a of the RAM 203 by the DMA operation. The input interface 204 is incorporated in the buckle of the seat belt, receives the opening / closing output of the buckle switch 307 that generates an output corresponding to the presence / absence of the belt, and also sets a flag indicating whether or not the belt is worn in the flag area of the RAM 203. . Further, the input interface 204 writes speed information output from the host vehicle speed detection device 402 described later in the speed area of the RAM 203.
[0021]
The communication interface 205 is constituted by a microcomputer system, and transmits a command output from the CPU 201 to the navigation device 401. Further, the output of the navigation device 401 is processed, and the processing result is written in a predetermined area of the RAM 203 by a DMA operation.
[0022]
The navigation device 401 receives a host vehicle speed detection device 402 that detects the traveling speed of the host vehicle, a GPS receiver 403 that receives a GPS satellite wave and measures the position of the host vehicle, and a D-GPS (differential GPS) service. FM multiplex receiver 403 having an FM data broadcast receiving function, a VICS device 405 for receiving road traffic information (VICS) that changes every moment, such as traffic jams, accidents, regulations, construction, etc., a web that provides traffic information on the Internet, and The navigation system 400 is configured together with the mobile phone device 406 and the like for making contact. The VICS device 405 can be built in the FM multiplex receiver 403.
[0023]
The navigation device 401 has a built-in CD-ROM or DVD-ROM in which various types of guide information such as road map information (including curves and intersections), traffic direction restrictions, accident-prone areas, parking lots, and drive-ins are recorded. The road map and the vehicle position are displayed on an LCD display (not shown) with reference to the vehicle position and road map information measured by the device or the inertial navigation device. In addition, road traffic information and construction regulation information are displayed on the LCD display.
[0024]
When there is a caution point (dangerous point) in the traveling direction of the host vehicle, for example, a curve, an intersection, a construction site, a restricted section, a frequent accident point, etc., the navigation device 401 has a distance Dn from the host vehicle position to the nearest caution point. , And the type of danger point are written in the reachable area of the RAM 203 via the communication interface 205. Further, the arrival time ta to the attention point is obtained by calculating Dn / v based on the current traveling speed v, and written in the arrival time area of the RAM 203.
[0025]
When a predetermined condition set in a control program, which will be described later, is satisfied, the CPU 201 gives a forward rotation command, a reverse rotation command, and a drive stop command for the motor 110 to the output interface 206. The output interface 205 generates gate signals G 1 and G 2 corresponding to these commands and supplies them to the motor drive circuit 206. For forward rotation commands, the gate signals G1 and G2 are set to “H” and “L”, respectively. For the reverse rotation command, the gate signals G1 and G2 are set to “L” and “H”, respectively, and a drive stop command is set. , G1 and G2 are set to “L” and “L”, respectively.
[0026]
FIG. 4 is a circuit diagram showing a configuration example of the motor drive circuit 210. A transistor bridge circuit is constituted by four transistors, PNP transistors Q1 and Q2, and NPN transistors Q3 and Q4. The emitters of the transistors Q1 and Q2 are connected to each other, and the power source Vc is supplied to the connection point. The emitters of the transistors Q3 and Q4 are also connected to each other, and a ground potential is supplied to the connection point. The collector of the transistor Q1 and the collector of the transistor Q3 are connected via a diode D1. The collector of the transistor Q2 and the collector of the transistor Q4 are connected via a diode D2. The base of the transistor Q1 and the collector of the transistor Q4 are connected via a bias resistor R1. The base of the transistor Q2 and the collector of the transistor Q3 are connected via a bias resistor R2. A DC electric motor M is connected between the collectors of the transistors Q1 and Q2.
[0027]
In such a configuration, when a normal rotation command signal (G1 = "H", G2 = "L") is supplied from the output interface 205 to the gates of the transistors Q3 and Q4, the transistor Q3 is turned on and the transistor Q4 is turned off. Become. The collector of the transistor Q3 is brought to the ground level by conduction, and the base of the transistor Q2 is biased to a low level (substantially ground level) via the resistor R2 to make the transistor Q2 conductive. The collector of the transistor Q4 is substantially at the power supply Vc level, biasing the base of the transistor Q2 to a high level via the resistor R1, and making the transistor Q1 non-conductive. As a result, a forward current path is formed by the path of the power source Vc, transistor Q2, motor M (motor 110), diode D1, transistor Q3, and ground, and the motor M rotates in the direction of winding the belt.
[0028]
When a reverse rotation command signal (G1 = "L", G2 = "H") is supplied from the output interface 205 to the gates of the transistors Q3 and Q4, the transistor Q3 is non-conductive and the transistor Q4 is conductive. The collector of the transistor Q4 is at the ground level, and the base of the transistor Q1 is biased to a low level via the resistor R1 to make the transistor Q1 conductive. The collector of the transistor Q3 is substantially at the power supply Vc level, biases the base of the transistor Q2 to a high level via the resistor R2, and makes the transistor Q2 non-conductive. As a result, a current path in the reverse direction is formed by the path of the power source Vc, the transistor Q1, the motor M, the diode D2, the transistor Q3, and the ground, and the motor M rotates in the direction of pulling out the belt.
[0029]
When a drive stop command signal (G1 = “L”, G2 = “L”) is supplied from the output interface 205 to the gates of the transistors Q3, Q4, the NPN transistors Q3, Q4 are both turned off. When the transistor Q3 is turned off from the conductive state, the collector of the transistor Q3 rises from the ground level to a substantially power supply level, biasing the base of the transistor Q2 to a high potential and also shutting off the transistor Q2. Similarly, when the transistor Q4 is turned off from the conducting state, the collector of the transistor Q4 rises from the ground level to a substantially power supply level, biasing the base of the transistor Q1 to a high potential and shutting off the transistor Q1. In this way, when a drive stop command is issued, each transistor constituting the bridge becomes non-conductive.
[0030]
FIG. 5 is a functional block diagram illustrating functions of the seat belt control system realized by the computer system of the control unit 200 and the navigation system 400 described above.
[0031]
As shown in the figure, the seat belt control system includes a host vehicle position detection unit 11, a map database holding unit 12, a collation unit 13, a danger point determination unit 14, a belt tension adjustment unit 15, a belt winding electric motor 110, and the like. Consists of. The own vehicle position detection unit 11 detects the position of the own vehicle (latitude, longitude, travel locus from the reference position) using a GPS device and / or an inertial navigation device. The map database holding unit 12 includes an electronic road map recorded on a CD-ROM or DVD-ROM. Preferably, the recording medium includes accident occurrence points on the road network, construction regulation information, and the like. In addition, traffic information from outside such as VICS, FM data broadcasting, the Internet, etc. is also stored in the database. The collation unit 13 collates the road map with the current traveling position of the host vehicle, and grasps the road situation in the traveling direction of the host vehicle. The own vehicle position detection unit 11 and the collation unit 13 correspond to own vehicle position detection means. On the road map, the danger point determination unit 14 is a road danger point on the road in the traveling direction of the host vehicle, such as a curve, an intersection, a distance between the accident occurrence point and the current travel position, or the current travel position to the danger point. Determine the arrival time. The belt tension adjusting unit 15 controls the electric motor 110 of the seat belt retractor 100 based on the distance or arrival time from the current point to the dangerous point and adjusts the tension of the seat belt. For example, when approaching a certain distance at the danger point, the tension of the seat belt is intermittently changed to alert the occupant. Further, when the vehicle approaches the danger point, the tension of the seat belt is maximized and the occupant is restrained to the seat except for belt slack.
[0032]
7 to 10 are flowcharts for explaining the operation of the CPU 201 of the control unit 200. First, the belt tension increase flag process will be described with reference to FIG. The CPU 201 executes this process at a predetermined cycle. The CPU 201 checks the seat belt wearing flag in the flag area of the RAM 203 (S12). When the seat belt wearing flag is off, that is, when the seat belt is not worn (S12; No), it is not necessary to adjust the belt tension, and thus this routine ends. When the seatbelt wearing flag is ON, that is, when the seatbelt is worn (S12; Yes), the distance Dn to the danger point ahead of the vehicle, which is written in the RAM 203 by the navigation device 401 by the DMA operation, is calculated. In the example, the distance Dn to the curve is read. It is determined whether or not the distance Dn is equal to or less than a predetermined reference distance D1, for example, 10 m (S14). When the distance is equal to or less than the reference distance D1 (S14; Yes), the tension increase flag for commanding the belt tension to be increased is turned on in the flag area of the RAM 203 in order to remove the slack of the seat belt before entering the danger point. Set (S16).
[0033]
If the host vehicle is not within the reference distance D1 (S14; No), it is determined whether another danger point, for example, an intersection is within the predetermined distance D1 in the traveling direction (S18). For example, when the distance is equal to or less than the reference distance D1 (S18; Yes), a tension increase flag for instructing to increase the belt tension is set in the flag area of the RAM 203 in order to remove the slack of the seat belt before entering the danger point. Set to ON (S16). If the host vehicle is not within the reference distance D1 (S18; No), there is no danger point within the predetermined range in the traveling direction, so the tension increase flag for commanding an increase in belt tension is set off (S20). Thereafter, the process returns to the original process.
[0034]
Note that step S18 can be omitted when a curve or intersection is simply determined as a dangerous point on the same basis. When discriminating dangerous spots by type as in this example, different judgment criteria are used, such as setting a predetermined distance separately for each risk content (curve, intersection, accident occurrence point, etc.) There are advantages that can be done.
[0035]
FIG. 8 shows a second example of the belt tension increasing process. In this example, in step 14a, whether or not the arrival time of the host vehicle to the first danger point (for example, a curve) is t1, for example, 1 second or less is used as a criterion (S14a). Step 1 8 In a, the arrival time of the host vehicle to the second danger point (for example, an intersection) is t 2 For example, it is determined whether or not it is 1 second or less (S1 8 a). The other processing is the same as the processing shown in FIG.
[0036]
FIG. 9 is a flowchart for explaining control in which the CPU 201 changes the tension of the seat belt to alert the occupant when the host vehicle approaches the danger point. The CPU 201 executes this subroutine at predetermined time intervals. First, the CPU 201 determines whether or not a seat belt is attached with reference to the seat belt flag in the flag area of the RAM 203 (S32).
[0037]
When the seatbelt wearing flag is off, that is, when the seatbelt is not worn (S32; No), the belt tension cannot be changed, and thus this routine ends. When the seat belt wearing flag is on (S32; Yes), it is determined whether or not the belt tension flag is set on (S34). When the belt tension flag is set to ON (S34; Yes), in this case, the host vehicle is in the dangerous point area, and it is not preferable to loosen the seat belt, so this routine ends.
[0038]
When the belt tension flag is not set to ON (S34; No), the area where the traveling speed is written in the RAM 203 is read, and it is determined whether or not the own vehicle speed is a predetermined value, for example, 50 km or more (S36). This predetermined speed value can be changed depending on, for example, accident occurrence point information, possibility of road surface freezing due to season / outside (road surface) temperature, and the like. When the host vehicle speed is equal to or lower than the predetermined speed, there is relatively little danger, so the warning may not be given due to a change in belt tension and the process may be terminated (S36; No).
[0039]
When the host vehicle speed is equal to or higher than the predetermined value (S36; Yes), the CPU 201 reads the distance Dn from the current position to the dangerous point from the RAM 202. It is determined whether a dangerous point exists within a predetermined distance D2 in the traveling direction, for example, within 50 m from the current point in the traveling direction. For example, it is determined whether or not a curve exists (S38). If it exists, the tension change flag is set to ON in order to alert the occupant by changing the tension of the seat belt (S40), and the process ends.
[0040]
If the curve does not exist (S38; No), it is determined whether or not there is an intersection within a predetermined distance D2 in the traveling direction of another dangerous point, for example, within 50 m of the traveling direction from the current point (S42). If it exists, the tension change flag is set to ON to change the seat belt tension to alert the occupant (S40), and the process ends. If there is no intersection, the tension change flag is set to OFF (S44), and the process ends.
[0041]
It should be noted that step 42 can be omitted when curves, intersections, accident-prone points, etc. are simply handled as dangerous points. In the case where the determination is made separately for each content of the dangerous point as in this embodiment, it is possible to set a separate threshold distance for each content of the dangerous point.
[0042]
FIG. 10 is a flowchart illustrating another example in which control for alerting the passenger is performed. In this example, the determination criterion up to the first danger point (for example, a curve) is the arrival time t3 to the danger point, for example, 5 seconds (S38a). Further, the determination criterion up to the second danger point (for example, an intersection) is the arrival time t4 to the danger point, for example, 5 seconds (S38a). The other processing is the same as the processing shown in FIG.
[0043]
FIG. 6 is a flowchart illustrating a procedure in which the CPU 201 performs belt tension adjustment. The CPU 201 performs this process at a predetermined cycle. First, referring to the flag area of the RAM 202, it is determined whether or not the tension increase flag is set to ON (S52). If the tension increase flag is set to ON (S52; Yes), the output interface 206 is commanded to increase the tension (forward rotation of the motor) (S54). As a result, the output interface 206 supplies a gate signal to the motor drive circuit 210 to operate the motor 110 in the belt winding direction. When the output of the potentiometer 111 in the winding direction is not changed, the winding of the motor 110 is stopped. As a result, the slack of the belt is removed, and the occupant is restrained by the seat.
[0044]
If the tension increase flag is not set to ON (S52; No), it is determined whether or not the tension increase flag was set to ON at the previous check (S56). When the tension increase flag is set to ON at the previous check (S56; Yes), the output interface 206 is instructed to reduce the belt tension (reverse rotation of the motor) (S58). Thereby, the motor 110 is rotated in the belt drawing direction by the motor driving circuit 210, and the belt restraint of the occupant is loosened. The belt withdrawal amount can be determined by the output value of the potentiometer 111.
[0045]
If the tension increase flag is not set to ON at the previous check (S56; No), the belt is not tightened (S56; No), and no processing is performed.
[0046]
Next, the CPU 201 determines whether or not the tension change flag in the flag area of the RAM 203 is set to ON (S62). When set to ON, the CPU 201 repeats sending the tension increase command and the tension decrease command to the output interface 206 alternately. The belt tension can be adjusted by referring to the output of the potentiometer. As a result, the occupant can be alerted by a periodic change in belt tension (S64). If the tension change flag is not set to ON (S62; No), the CPU 201 determines whether or not the tension increase / decrease has been repeated at the previous check (S66). If the tension increase / decrease is repeated during the previous check (S66; Yes), there is no need to call attention (or warning), so the CPU 201 alternately sends a tension increase command and a tension decrease command (see S64). This is stopped (S68) and the process ends. If the increase / decrease of the tension has not been repeated at the previous check (S66; No), the process ends.
[0047]
In this way, when the host vehicle approaches the danger point, the tension of the seat belt is increased and the safety of the passenger is as much as possible.
[0048]
【The invention's effect】
As described above, the seat belt device according to the present invention compares the position of the host vehicle with the dangerous point on the map, and controls the tension of the seat belt according to the signal given when the host vehicle approaches the dangerous point. The passenger is restrained by the seat before traveling on the spot, and it can be expected to improve the passenger protection. Further, when approaching the danger point, attention is drawn by fluctuations in the tension of the seat belt, so that the condition is good.
[Brief description of the drawings]
FIG. 1 is an explanatory view illustrating a seat belt device.
FIG. 2 is an explanatory diagram illustrating an electric winding device that winds a seat belt with an electric motor.
FIG. 3 is a block diagram illustrating a control system of the seat belt control system.
4 is a circuit diagram showing a configuration of a motor drive circuit 210. FIG.
FIG. 5 is a functional block diagram of the seat belt control system.
FIG. 6 is a flowchart for explaining belt tension adjustment and belt tension change control by a CPU 201;
FIG. 7 is a flowchart for explaining an on / off setting example of a belt tension flag by the CPU 201;
FIG. 8 is a flowchart for explaining another example of the belt tension flag on / off setting by the CPU 201;
FIG. 9 is a flowchart for explaining an on / off setting example of a belt tension change flag by the CPU 201;
FIG. 10 is a flowchart for explaining an example of setting on / off of another belt tension change flag by the CPU 201;
[Explanation of symbols]
100 Electric belt winding device
200 Control unit
302 seat belt
400 navigation system

Claims (2)

A seat belt for restraining an occupant to a seat, and a belt winding device that winds and pulls out the seat belt by an electric motor;
Provided with a database including at least road map information, and detects a current travel position of the host vehicle on the road map, and a road danger point and the current travel in the traveling direction of the host vehicle on the road map. The electric motor using the distance to the position or the arrival time from the current travel position to the danger point, and the distance or time discrimination criteria set separately for each danger content of the danger point Seat belt control means for controlling and adjusting the tension of the seat belt;
A seat belt device comprising: The seat belt control means includes
The tension of the seat belt when the distance between the dangerous point and the current traveling position or the arrival time from the current traveling position to the dangerous point is equal to or less than a first reference distance or equal to or less than a first reference time. The change alerts the crew,
The distance between the dangerous point and the current traveling position, or the arrival time from the current traveling position to the dangerous point is equal to or less than a second reference distance that is smaller than the first reference distance or from the first reference time. The seatbelt device according to claim 1, wherein when the time becomes equal to or smaller than a small second reference time, the tension of the seatbelt is set to be large .

Images