JP2001010447A - Seatbelt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vary the tension of a seatbelt according to the degree of danger in an area (block) in which a vehicle is traveling or a travel point (site). SOLUTION: A navigation system detects the position of a vehicle (11-13), and increases seatbelt tension in advance before reaching a curve or a dangerous point such as a crossing (14, 15, 110), thus providing effective occupant restraint even in the event of a collision. Since the probability of accidents is high at curves or crossings, the tension of the seatbelt is intermittently varied for alarming if the speed of the vehicle is equal to or greater than a predetermined value before the vehicle enters the curve or crossing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle seatbelt device for restraining an occupant in a seat to secure the occupant, and more particularly to a vehicle seatbelt device, and more particularly, to an electric machine such as an electric motor. The present invention relates to a seat belt device using a seat belt winding device using a dynamic power source.

[0002]

2. Description of the Related Art Conventionally, a device that measures the distance between obstacles using a radar or the like, predicts a collision based on the distance, varies the tension of a seat belt, and issues an alarm or a rise in tension, for example, It is proposed in Japanese Utility Model Laid-Open No. 6-71333. According to such a device, when an obstacle is detected, the device functions effectively, so that an effect is expected to ensure the safety of the occupant.

[0003]

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 quite a few cases in which the other vehicle suddenly appears over the center line and leads to a collision. At intersections, there are quite a few cases where the vehicle collides with a vehicle that suddenly crosses ahead of the host vehicle.

Therefore, even if an obstacle can be detected by the radar, the obstacle is detected immediately before the collision. In a device in which the tension of the seat belt can be changed by electric power, the time that can be moved before the collision is short. There is a possibility that the effect cannot be sufficiently exhibited.

Accordingly, it is an object of the present invention to provide a seat belt device capable of changing the tension of a seat belt according to the degree of danger of a region (area) where a host vehicle is traveling or a traveling point (location). And

Another object of the present invention is to provide a seat belt device which draws attention to an occupant when entering or traveling in a high-risk area (area) or a traveling point (place). Aim.

Another object of the present invention is to provide a seat belt device that works in conjunction with a navigation system that guides driving of a vehicle.

[0008]

In order to achieve the above object, a seat belt device according to the present invention comprises a seat belt for restraining an occupant in a seat, and a belt winding device for winding and drawing out the seat belt by an electric motor. And a database including at least road map information to detect a current traveling position of the own vehicle on the road map, and to detect a danger point of a road in the traveling direction of the own vehicle on the road map and the current A seat that controls the electric motor in accordance with a determination output signal from a travel guide device that determines a distance from the current travel position or an arrival time from the current travel position to the danger point to adjust the tension of the seat belt. Belt control means.

Preferably, the dangerous points include a curve, an intersection, a point where accidents frequently occur, and a construction restriction point.

[0010] Preferably, the seat belt control means includes a distance between the dangerous point and the current traveling position or an 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 reference time. In the case of, the occupant is alerted by the change in seat belt tension.

[0011] Preferably, the seat belt control means includes: a distance between the danger point and the current traveling position or an arrival time from the current traveling position to the danger point being smaller than the first reference distance. When the distance is equal to or less than the second reference distance or the second reference time that is shorter than the first reference time, the tension of the seat belt is set to be large.

Preferably, the traveling position detecting means is G
The navigation device includes at least one of a PS device, a D-GPS device, an inertial navigation device, and road-to-vehicle communication (VICS).

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 vehicle approaches the danger point when the vehicle speed is equal to or higher than a predetermined value, the seatbelt control device intermittently controls the tension of the seatbelt. It is variable and calls attention to the crew.

Further, the seat belt control system of the present invention comprises a belt winding device for winding and pulling out a seat belt by an electric motor, a database including at least road map information, Traveling position detecting means for detecting a current traveling position of the vehicle, and a distance between a dangerous point on a road in the traveling direction of the vehicle and the current traveling position on the road map or from the current traveling position to the dangerous point. Danger determining means for determining the arrival time of the vehicle, and seat belt control means for controlling the electric motor in accordance with the determination result to adjust the tension of the seat belt.

With this configuration, the position of the host vehicle is detected, and the seat belt tension is increased in advance of a danger point such as a curve or an intersection. By any chance,
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 there is a high probability of an accident at a carp or an intersection, if the vehicle speed is equal to or higher than a predetermined value before advancing, the tension of the seat belt is intermittently varied for a warning to give a warning.

[0017]

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 provided with an electric winding device 100 that winds a belt 302 that restrains an occupant on a seat 301 by an electric motor, a through anchor 303 that turns the belt 302 near a shoulder of the occupant, and a waist portion that is inserted through the belt. Tongue plate 305 and belt 30 engaging with buckle 304
Anchor 306 for fixing the end of 2 to the vehicle body, switch 307 built in the buckle, control unit 200 (not shown)
Etc.

FIG. 2 is an explanatory view schematically illustrating the configuration of the electric winding device 100. In the figure, the taking device 100 includes a frame 101. The frame 101 has a reel 10 around which a belt (not shown) is wound.
3. A reel shaft 103a, which is connected to the reel 103 and serves as a center axis of rotation of the reel, is rotatably provided. A known seat belt locking mechanism 102 that locks the seat belt withdrawal when a predetermined deceleration acts on the vehicle or when the belt is pulled out with a predetermined acceleration is fixed to a 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 activated by the output of a collision detector (not shown), rotates the reel shaft 103a in the belt winding direction, and forcibly winds the belt to restrain the occupant to the seat. The pretensioner 104 is, for example, an explosive-type pretensioner, and controls 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 through a clutch mechanism. And a transmission mechanism for converting the rotational motion of the reel shaft 103a. The pulley 105 fixed to the reel shaft 103a is connected to a 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 circumference of each of the pulleys 105 and 106, and a predetermined number of internal teeth are also formed on the inner circumference of the belt 107. Pulley 105 for reel shaft, pulley 106 for motor, belt 10
The teeth of No. 7 are meshed without excess or shortage, 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 by an output of the control unit 200.

The potentiometer 111 provided at the leftmost end of the reel shaft 103a is a well-known potentiometer.
And a slider interlocked with the rotation of 3a. Then, a voltage value corresponding to the rotation amount from the reference position of the reel shaft 103a is output to the control unit 200.

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 sets R
The control program and data held in the OM 202 are
It is loaded into the work area of M203, executes various programs described later, and controls operations such as forward rotation, reverse rotation, and stop of the motor 110. Potentiometer 111 described above
Is output from the input interface 204 in a predetermined cycle. 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 “shaft rotating” flag 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 small), a flag of "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,
A “pull-out” (reverse rotation of the shaft 103a) flag or a “wind-up” (forward rotation of the shaft 103a) flag of the belt is set in the flag area of the RAM 203. Also,
The output voltage data is written into the rotation amount area of the shaft 103a of the RAM 203 by the DMA operation. The input interface 204 receives the opening / closing output of the buckle switch 307 that is built into the buckle of the seat belt and generates an output corresponding to the presence / absence of the belt, and also sets a flag for the presence / absence of the belt in the flag area of the RAM 203. .
The input interface 204 stores speed information output from the host vehicle speed detection device 402 described later in the RAM 203.
Write in the speed range of.

The communication interface 205 is constituted by a microcomputer system, and transmits a command output from the CPU 201 to the navigation device 401.
In addition, processing such as processing the output of the navigation device 401 and writing the processing result to a predetermined area of the RAM 203 by a DMA operation is performed.

The navigation device 401 includes a host vehicle speed detecting device 402 for detecting a running speed of the host vehicle, a GPS receiving device 403 for receiving a radio wave of a GPS satellite to measure the position of the host vehicle, and a D-GPS (differential GPS).
FM multiplex receiver 403 with FM data broadcast receiving function for receiving service, VICS device 405 for receiving road traffic information (VICS) that changes every moment such as traffic jams, accidents, regulations, construction, etc., and provides traffic information on the Internet The navigation system 400 is configured together with the mobile phone device 406 and the like that make contact with the web to be contacted. Note that the VICS device 405 can be built in the FM multiplex receiver 403.

The navigation device 401 has a built-in CD-ROM or DVD-ROM in which various kinds of guidance information such as road map information (including curves and intersections), traffic direction restrictions, accident-prone zones, parking lots, and drive-ins are recorded. , GP
The road map and the own vehicle position are displayed on an LCD display (not shown) with reference to the own vehicle position and the road map information measured by the S receiving device or the inertial navigation device. Also, road traffic information and construction regulation information are displayed on the LCD display.

When there are caution points (dangerous points) in the traveling direction of the vehicle, such as curves, intersections, construction sites, restricted sections, and accident-prone points, the navigation device 401 moves from the vehicle position to the closest caution point. The distance Dn and the type of danger point to the communication interface 2
The data is written in the reachable area of the RAM 203 via the interface 05. Further, based on the current traveling speed v, the arrival time ta to the attention point is calculated by calculating Dn / v, and RA
Write to the arrival time area of M203.

When a predetermined condition set in a control program described later is satisfied, the CPU 201
Are given to the output interface 206. The output interface 205 generates gate signals G1 and G2 corresponding to these instructions, and supplies them to the motor drive circuit 206. For forward rotation command,
The gate signals G1 and G2 are set to “H” and “L”, respectively, the gate signals G1 and G2 are set to “L” and “H” for the reverse rotation command, and the gate signals G1 and G are set for the drive stop command.
2 are set to “L” and “L”, respectively.

FIG. 4 is a circuit diagram showing a configuration example of the motor drive circuit 210. PNP transistors Q1, Q2, N
The four PN transistors Q3 and Q4 form a transistor bridge circuit. The emitters of the transistors Q1 and Q2 are connected to each other, and the connection point is supplied with power Vc. 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.

In such a configuration, the transistors Q3,
A forward rotation command signal (G1 = “H”, G2 =
When "L") is supplied from the output interface 205, the transistor Q3 is turned on and the transistor Q4 is turned off. 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 the ground level) via the resistor R2 to make the transistor Q2 conductive. The collector of the transistor Q4 is substantially at the level of the power supply Vc, and the base of the transistor Q2 is biased to a high level via the resistor R1.
Is made non-conductive. As a result, a forward current path is formed by the path of the power supply Vc, the transistor Q2, the motor M (motor 110), the diode D1, the transistor Q3, and the ground, and the motor M rotates in the direction of winding the belt.

When a reverse command signal (G1 = "L", G2 = "H") is supplied to the gates of the transistors Q3 and Q4 from the output interface 205, the transistor Q3 is turned off and the transistor Q4 is turned on. 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 level of the power supply Vc, and the transistor Q3 is connected via the resistor R2.
The base of 2 is biased high, causing transistor Q2 to become non-conductive. As a result, the power supply Vc and the transistor Q
1. A current path in the opposite direction is formed by the path of the motor M, the diode D2, the transistor Q3, and the ground, and the motor M rotates in a direction to pull out the belt.

When a drive stop command signal (G1 = "L", G2 = "L") is supplied to the gates of the transistors Q3 and Q4 from the output interface 205, the NPN type transistors Q3 and Q4 are both turned off. Become. Transistor Q
When the transistor 3 changes from the conductive state to the non-conductive state, the transistor Q3
Collector rises from ground level to near power level,
The base of the transistor Q2 is biased to a high potential to shut off the transistor Q2. Similarly, when the transistor Q4 changes from the conductive state to the non-conductive state, the collector of the transistor Q4 rises from the ground level to substantially the power supply level, and the base of the transistor Q1 is biased to a high potential to shut off the transistor Q1. In this way, when the drive stop command is issued, each transistor constituting the bridge becomes non-conductive.

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.

As shown in FIG. 1, the seat belt control system includes a vehicle position detecting unit 11, a map database holding unit 12, a collating unit 13, a dangerous spot discriminating unit 14, a belt tension adjusting unit 15, and an electric motor for winding the belt. It is constituted by a motor 110 and the like. The own vehicle position detecting unit 11 detects the position of the own vehicle (latitude, longitude, running trajectory from the reference position) using a GPS device and / or an inertial navigation device. The map database holding unit 12 stores a CD-ROM or DVD-R
Includes an electronic road map recorded in the OM. Preferably, the recording medium includes a location where accidents frequently occur on the road network, construction regulation information, and the like. It should be noted that traffic information from the outside via VICS, FM data broadcasting, the Internet or the like is also stored in the database. The collating unit 13 collates the road map with the current traveling position of the own vehicle, and grasps the road condition in the traveling direction of the own vehicle. Own vehicle position detecting section 11 and collating section 1
Reference numeral 3 corresponds to the vehicle position detecting means. Danger point discriminator 1
Reference numeral 4 denotes a danger point on the road in the traveling direction of the vehicle on the road map, for example, a distance between a curve, an intersection, an accident-prone point and the current traveling position, or a time required to reach the dangerous point from the current traveling position. I do. The belt tension adjusting unit 15 controls the electric motor 110 of the seat belt retractor 100 based on the distance or the arrival time between the current point and the danger point, and adjusts the seat belt tension.
For example, when approaching a distance to a danger point, the tension of the seat belt is intermittently changed to alert the occupant. Furthermore,
When the vehicle approaches the danger point, the occupant is restrained in the seat except for the slack of the belt by maximizing the tension of the seat belt.

FIGS. 7 to 10 show the CPU of the control unit 200.
4 is a flowchart for explaining the operation of FIG. First,
The belt tension increase flag processing will be described with reference to FIG. The CPU 201 executes this processing at a predetermined cycle. The CPU 201 checks the seat belt fastening flag in the flag area of the RAM 203 (S12). If the seatbelt wearing flag is off, that is, if the seatbelt is not worn (S12; No), there is no need to adjust the belt tension, so this routine ends. When the seat belt wearing flag is ON, that is,
When the seat belt is worn (S12; Yes)
Means that the navigation device 401 performs R
Distance D to danger point ahead of vehicle written in AM203
In this case, the distance Dn to the curve is read. The distance Dn is equal to or less than a predetermined reference distance D1, for example, 10
It is determined whether the value is equal to or less than m (S14). If the distance is less than or equal to the reference distance D1 (S14; Yes), the RAM 20 is used to remove slack in the seat belt before entering the danger point.
In a flag area of No. 3, a tension increasing flag for instructing to increase the belt tension is set to ON (S16).

When the vehicle is not within the reference distance D1 (S1
4; No), it is determined whether or not another dangerous point, for example, an intersection is within a predetermined distance D1 in the traveling direction (S1).
8). For example, when the distance is equal to or less than the reference distance D1 (S18;
Yes), in order to remove the slack of the seat belt before entering the danger point, a tension increase flag instructing to increase the belt tension is set to ON in a flag area of the RAM 203 (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 instructing an increase in belt tension is set to off (S20). Then, the process returns to the original process.

When a curve or an intersection is determined simply as a danger point on the same basis, step S18 can be omitted. As in this example, when the danger points are determined for each type, each danger content (curve,
There is an advantage that different determination criteria can be used, such as setting a predetermined distance separately for each intersection, a point where accidents frequently occur, and the like.

FIG. 8 shows a second example of the belt tension increasing process. In this example, in step 14a, whether the arrival time of the host vehicle to the first danger point (for example, a curve) is less than or equal to t1, for example, 1 second is used as a determination criterion (S14a). Step 14a
In step S14a, whether the arrival time of the host vehicle to the second danger point (for example, an intersection) is less than or equal to t1, for example, 1 second (S14a). The other processing is the same as the processing shown in FIG.

FIG. 9 is a flowchart for explaining a control in which the CPU 201 changes the tension of the seatbelt to draw the occupant's attention when the vehicle approaches the danger point. The CPU 201 executes this subroutine at predetermined time intervals. First, the CPU 201 determines whether or not the seat belt is worn by referring to the seat belt flag in the flag area of the RAM 203 (S32).

When the seat belt wearing flag is off, that is, when the seat belt is not worn (S3
2; No), this routine ends because the belt tension cannot be changed. If 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 (S3
4; Yes), in this case, the vehicle is in the area of the danger point, and it is not preferable to loosen the seat belt, so this routine ends.

If the belt tension flag is not set to ON (S34; No), the area where the running speed is written in the RAM 203 is read, and the own vehicle speed is set to a predetermined value, for example,
It is determined whether it is 50 km or more (S36). This predetermined speed value can be changed based on, for example, information on the location of frequent occurrence of accidents, the possibility of freezing the road surface due to the season and the outside (road surface) temperature, and the like. When the own vehicle speed is equal to or lower than the predetermined speed, there is relatively little danger, and the process may end without issuing a warning due to a change in belt tension (S36; No).

When the vehicle speed is equal to or higher than a predetermined value (S36;
Yes), the CPU 201 reads the distance Dn from the current position to the danger point from the RAM 202. Within a predetermined distance D2 in the traveling direction, for example, 50 m in the traveling direction from the current point
It is determined whether or not there is a danger point. For example, it is determined whether a curve exists (S38). If there is, the tension change flag is set to ON to change the tension of the seat belt to call attention to the occupant (S40),
finish.

If no curve exists (S38; N
o), it is determined whether an intersection exists within a predetermined distance D2 in the traveling direction of another dangerous point, for example, within 50 meters of the traveling direction from the current point (S42). If there is, the tension change flag is set to ON to change the tension of the seat belt 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.

When a curve, an intersection, a point where accidents frequently occur, or the like is simply treated as a dangerous point, step 42 can be omitted. In the case where the determination is made separately for each content of the danger point as in this embodiment, it is possible to set a separate threshold distance for each content of the danger point.

FIG. 10 is a flowchart showing another example of performing control to call attention to the occupant. 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 (S
38a). In addition, a criterion for determining a second danger point (for example, an intersection) is determined by an arrival time t4 to a danger point, for example,
5 seconds (S38a). The other processing is the same as the processing shown in FIG.

FIG. 6 is a flowchart showing a procedure in which the CPU 201 adjusts the belt tension. CPU201
Performs this processing 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), an instruction to increase the tension (normal rotation of the motor) is issued to the output interface 206 (S54). Thereby, the output interface 20
6 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 does not change in the winding direction, the winding of the motor 110 is stopped. As a result, the slack of the belt is eliminated, and the occupant is restrained by the seat.

If the tension increase flag is not set to ON (S52; No), it is determined whether the tension increase flag was set to ON at the time of the previous check (S56).
If the tension increase flag is set to ON at the time of the previous check (S56; Yes), the output interface 206 is instructed to decrease the belt tension (reverse rotation of the motor) (S5).
8). Thereby, the motor 110 rotates in the belt withdrawing direction by the motor driving circuit 210, and the restraint of the occupant by the belt is released. The belt withdrawal amount can be determined by the output value of the potentiometer 111.

If the tension increase flag has not been set to ON at the time of the previous check (S56; No), the belt is not tightened (S56; No), so no particular processing is performed.

Next, the CPU 201 determines whether or not the tension change flag in the flag area of the RAM 203 has been set to ON (S62). If set to on, CP
U201 repeats sending the tension increase command and the tension decrease command to the output interface 206 alternately.
It is possible to adjust the belt tension by referring to the output of the potentiometer. As a result, the occupant may be alerted by the periodic change of the belt tension (S64). If the tension change flag is not set to ON (S62; No), the CPU 201 determines whether or not the increase / decrease of the tension was repeated at the previous check (S62).
66). When the tension is repeatedly increased and decreased during the previous check (S66; Yes), a warning (or a warning) is issued.
Therefore, the CPU 201 stops sending the tension increase command and the tension decrease command alternately (see S64) (S68), and ends. If the increase / decrease of the tension has not been repeated at the previous check (S66; No), the process ends.

As described above, when the vehicle approaches the danger point, the tension of the seat belt is increased, and occupant safety is improved as much as possible.

[0048]

As described above, the seatbelt device of the present invention compares the position of the vehicle with the danger point on the map, and detects the tension of the seatbelt based on a signal given when the vehicle approaches the danger point. Since the control is performed, the occupant is restrained by the seat before traveling at the dangerous point, and improvement in occupant protection can be expected. In addition, when approaching a danger point, a change in the tension of the seat belt draws attention to the situation, which is convenient.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram 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.

FIG. 4 is a circuit diagram showing a configuration of a motor drive circuit 210.

FIG. 5 is a functional block diagram illustrating the seatbelt control system.

FIG. 6 is a diagram illustrating belt tension adjustment by the CPU 201;
6 is a flowchart illustrating control of belt tension change.

FIG. 7 is a flowchart illustrating an example of ON / OFF setting of a belt tension flag by a CPU 201;

FIG. 8 is a flowchart illustrating another example of ON / OFF setting of the belt tension flag by the CPU 201.

FIG. 9 is a flowchart illustrating an example of setting a belt tension change flag on / off by a CPU 201;

FIG. 10 is a flowchart illustrating an example of ON / OFF setting of another belt tension change flag by the CPU 201;

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 electric belt winding device 200 control unit 302 seat belt 400 navigation system

Claims (1)

[Claims] 1. A seat belt for restraining an occupant to a seat, a belt winding device for winding and pulling out the seat belt by an electric motor, and a database including at least road map information,
The current travel position of the own vehicle on the road map is detected, and the distance between the danger point of the road and the current travel position in the traveling direction of the own vehicle on the road map or the current travel position is calculated from the current travel position. A seat belt control unit that controls the electric motor in accordance with a determination output signal from a traveling guide device that determines a time required to reach the seat belt and adjusts the tension of the seat belt.