JP2020097358A - Seat belt device - Google Patents

Abstract

To provide a seat belt device that can set an upper limit value of an optimal load for drawing out.SOLUTION: A seat belt device comprises: a webbing 41 that constrains an occupant to a seat in a vehicle; a spool 51 that rotates to be able to wind up and draw out the webbing 41; a rotation inhibiting mechanism that inhibits the spool 51 from rotating at the time of collision of the vehicle to restrict the spool from drawing out the webbing 41; a load restricting mechanism that allows the spool 51 to rotate, when a load for drawing out not less than a limit value in a drawing-out direction of the webbing 41 acts on the spool 51, with rotation of the spool 51 inhibited; a motor 61 that imparts to the spool 51 torque for rotating the spool in a winding-up direction or in a drawing-out direction of the webbing 41; and control means that controls the motor 61 at the time of the collision so that torque to be imparted to the spool 51 is adjusted, which can increase and decrease a set upper limit value of the load for drawing out the webbing 41 at the time of the collision with respect to the limit value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a seat belt device installed in a vehicle such as an automobile.

A seat belt device equipped in a vehicle such as an automobile restrains the occupant with a seat belt when a large acceleration (deceleration) is applied to the vehicle body, such as at the time of collision of the vehicle. Prevents passengers from jumping out and protects passengers. For restraining the occupant, the ELR (Emergency Locking Retractor) mechanism that locks the seat belt pull-out and the pull-out load (impact load that acts on the occupant from the seat belt) to pull out the seat belt when the ELR mechanism is operating exceed a predetermined value. A force limiter mechanism is used to limit the pull-out load by pulling out the seat belt so that it will not occur.

As the force limiter mechanism, a mechanism is generally adopted in which the withdrawal load is limited by torsionally deforming the torsion bar in the seatbelt retractor according to the withdrawal of the seatbelt under the operation of the ELR mechanism.

In addition, in order to realize more diverse energy absorption characteristics, in addition to the force limiter mechanism using a torsion bar, various mechanisms are used to increase the upper limit of the withdrawal load for a certain amount of belt withdrawal. It has been proposed to make it variable (Patent Documents 1 and 2).

In addition, by adding a motor to the winding mechanism of the seat belt device, the slack of the seat belt can be removed, assisting in putting on and taking off the seat belt, danger notification when the vehicle is judged to be in danger of collision, and the occupant. However, in a certain type of seat belt with a motor, it has been proposed that the upper limit value of the withdrawal load be increased and varied by operating the motor during a collision (Patent Document 1). 3, 4).

JP-A-2002-53007 JP 2008-14659 A JP, 2011-93431, A JP, 2009-262811, A

In the seat belt withdrawal amount sensitive variable force limiter seat belt and the electric signal sensitive variable force limiter seat belt as shown in Patent Documents 1 and 2, the variable amount of the upper limit value of the withdrawal load is only high and low two stages and a combination thereof. Few. In addition, there are major restrictions on further increasing the upper limit of the withdrawal load in all aspects of size, weight, and cost. Therefore, there is room for improvement in setting the optimum upper limit value of the withdrawal load according to the situation of the occupant or the like.

Further, a normal seat belt with a motor does not operate at the time of a collision (after the collision starts), and the existing airbag and seat belt mainly work. Therefore, the contribution to the occupant protection performance in a collision is limited. Further, as shown in Patent Documents 3 and 4, there is a prior art of a type that operates at the time of collision, but there is room for improvement in setting the optimum upper limit value of the withdrawal load.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a seat belt device capable of setting an optimum upper limit value of the withdrawal load.

A seat belt device according to a first invention for solving the above-mentioned problems,
Webbing to restrain the occupant to the vehicle seat,
A spool that winds the webbing and rotates so that it can be pulled out,
A rotation blocking mechanism that blocks the rotation of the spool at the time of the collision of the vehicle and prohibits the withdrawal of the webbing,
A load limiting mechanism that allows the spool to rotate when a withdrawal load equal to or more than a limit value acts on the spool in the webbing withdrawing direction while the spool is prevented from rotating,
A motor that applies a torque to the spool to rotate it in the winding direction or the drawing direction of the webbing;
Control means for controlling the motor at the time of the collision and adjusting the torque applied to the spool,
The upper limit value of the withdrawal load for pulling out the webbing at the time of the collision can be increased or decreased with respect to the limit value.

A seat belt device according to a second invention for solving the above-mentioned problems,
In the seat belt device according to the first invention,
The control means increases the upper limit value of the pull-out load above the limit value by applying a torque for rotating the spool in the winding direction of the webbing to the spool by the motor. On the other hand, by applying a torque to rotate the webbing in the pull-out direction, the upper limit value of the pull-out load is reduced below the limit value, and the torque of the motor is unloaded, whereby the upper limit value of the pull-out load is set. Is set as the limit value.

A seat belt device according to a third invention for solving the above-mentioned problems,
In the seat belt device according to the first or second invention,
A sensor for acquiring information on at least one of the occupant and the vehicle,
The control means may determine the rotation direction of the motor, the magnitude of the torque to be applied, the timing of application, and the duration based on the information acquired by the sensor.

According to the present invention, the torque for rotating in one rotation direction or the other rotation direction at the time of collision is applied to the spool from the motor to increase or decrease the upper limit value of the withdrawal load. Can be set.

It is a schematic diagram showing a vehicle which has a seat belt device concerning the present invention. It is a schematic diagram showing a seat belt device concerning the present invention. FIG. 3 is a view of the seat belt device shown in FIG. 2, taken along the line AA. It is a figure explaining the operation area and function of the conventional seat belt device and the seat belt device concerning the present invention. It is a graph explaining the load characteristic in the conventional seat belt with a motor. It is a graph explaining the load characteristic in the conventional variable force limiter seat belt. It is a graph explaining the load characteristic in the seat belt device according to the present invention.

Embodiments of a seat belt device according to the present invention will be described below with reference to FIGS.

[Example 1]
As shown in FIG. 1, the seat belt device according to the present embodiment is installed in a vehicle 10 such as an automobile, and prevents the occupant 11 from jumping out of a seat (not shown) by a webbing 41 of a seat belt device body 40. This is a safety device that protects the occupant 11.

As shown in FIGS. 2 and 3 described later, the seatbelt device body 40 includes a motor 61, and the operation of the motor 61 is controlled by the seatbelt control device 20. A sensor unit 30 including an occupant information sensor, a vehicle information sensor, a collision prediction sensor, and the like is connected to the seat belt control device 20. The seatbelt control device 20 controls the rotation direction (normal rotation, reverse rotation) of the motor 61 described later, the magnitude of the torque to be applied, the timing at which it acts, and the duration time, based on the information from these sensors, and will be described later. The seat belt device main body 40 is controlled by controlling the upper limit value of the withdrawal load and controlling the optimum working load of the force limiter.

In the sensor unit 30, the occupant information sensor is, for example, a weight detection device that acquires the weight of the occupant 11 or a seat position detection device that acquires the seating position of the occupant 11, and the vehicle information sensor is, for example, the speed of the vehicle 10. And a relative speed detection device that acquires the relative speed with respect to the collision target, and the collision prediction sensor is, for example, a radar, a sonar, a camera, or the like that detects the collision target.

Next, the configuration of the seatbelt device main body 40 will be described with reference to FIGS. 2 and 3 together with FIG. 1. The seat belt device main body 40 includes a webbing 41 that restrains the occupant 11 to the seat of the vehicle 10, and a spool 51 that winds the webbing 41 and rotates so that the webbing 41 can be pulled out to adjust the length of the webbing 41 (belt withdrawal amount). It has a retractor 50 which is a winding device provided.

The retractor 50 has a spool 51, a lock wheel 52, an ELR wheel 53, and a torsion bar 54.

The spool 51 is formed in a substantially cylindrical shape and is rotatably supported by the housing 50 a of the retractor 50. One end of the webbing 41 is fixed to the spool 51, and the webbing 41 is wound by rotating the spool 51 by the urging force of a spring (not shown). Both ends 51a, 51b of the spool 51 are formed to have a larger diameter than the portion for winding the webbing 41, and serve as guides for winding the webbing 41. Note that, hereinafter, the direction in which the spool 51 winds the webbing 41 (the winding direction of the webbing 41) is referred to as the pull-in direction, and the direction in which the webbing 41 is pulled out from the spool 51 is called the pull-out direction.

The lock wheel 52 is formed in a substantially disc shape and is rotatably supported by the housing 50a. When the pull-out acceleration detection unit 55 detects that the pull-out acceleration of the webbing 41 exceeds a predetermined value, the lock wheel 52 receives a relative rotational force in the pull-out direction with respect to the ELR wheel 53. The rotation is prevented by the lock wheel lock member 56.

The ELR wheel 53 is formed in a substantially disc shape, is arranged on the outer side in the axial direction of the lock wheel 52, and is rotatably supported by the housing 50a together with the lock wheel 52. The ELR wheel 53 is configured to be prevented from rotating by the ELR wheel lock member 58 when the vehicle body acceleration detection unit 57 detects that the vehicle body acceleration of the vehicle body exceeds a predetermined value.

The torsion bar 54 is inserted into the spool 51 and has one end supported by the lock wheel 52 and the other end supported by the end portion 51a. That is, in the retractor 50, the rotational movement (rotational force) is transmitted between the spool 51 and the lock wheel 52 via the torsion bar 54. The torsion bar 54 defines the limit value of the withdrawal load when the webbing 41 is withdrawn. Here, the limit value of the withdrawal load is a fixed value determined by the rigidity of the torsion bar 54. On the other hand, the upper limit value of the withdrawal load described later is a variable value that can be increased or decreased with respect to the above limit value.

In the present embodiment, the lock wheel 52, the ELR wheel 53, the pull-out acceleration detection unit 55, the lock wheel lock member 56, the vehicle body acceleration detection unit 57, the ELR wheel lock member 58, and the like prevent the spool 51 from rotating during a collision. An ELR mechanism (rotation blocking mechanism) that prohibits the webbing 41 from being pulled out is configured.

The ELR mechanism described above uses the lock wheel 52, the ELR wheel 53, and the lock wheel lock member 56 and the ELR wheel lock member 58 when a large acceleration or deceleration is applied to the vehicle body of the vehicle 10 (for example, at the time of a collision). To prevent the occupant 11 from jumping out of the seat and protect the occupant 11 by blocking the rotation of the spool 51 and the rotation of the spool 51 and locking the drawer of the webbing 41.

The torsion bar 54 operates when the ELR mechanism is activated, that is, when the spool 51 is prevented from rotating and a pulling load equal to or more than the above limit value acts on the spool 51 in the pulling direction of the webbing 41. Of the webbing 41 is allowed to be pulled out, and when the webbing 41 is pulled out, the kinetic energy during that time is absorbed and the impact load acting on the occupant 11 from the webbing 41 is reduced. That is, the torsion bar 54 functions as a load limiting mechanism that limits the pull-out load of the webbing 41. In addition to this, in this embodiment, in order to optimally set the upper limit value of the withdrawal load, in order to be able to increase or decrease the setting of the upper limit value of the withdrawal load with respect to the above limit value, it has the following configuration. ing.

Specifically, in this embodiment, the motor 61 is connected to the spool 51 via the drive gear 62, the counter gear 63, and the driven gear 64, and the motor 61 pulls the webbing 41 from the spool 51 in the pulling direction or It is configured to apply a torque for rotating in the pull-out direction. In addition, hereinafter, the rotation of the motor 61 in the pull-in direction is referred to as forward rotation, and the rotation of the motor 61 in the pull-out direction is referred to as reverse rotation.

More specifically, the motor 61 is attached to the housing 50a, and the drive gear 62 is attached to the output shaft of the motor 61. The counter gear 63 is rotatably supported by the housing 50 a, is arranged between the drive gear 62 and the driven gear 64, and is arranged so as to mesh with the drive gear 62 and the driven gear 64. The driven gear 64 is attached to the spool 51 coaxially with the spool 51. That is, the drive gear 62, the counter gear 63, and the driven gear 64 are a power transmission mechanism of the motor 61.

The seatbelt control device 20 has a motor drive control device (not shown), and the motor 61 is controlled by the seatbelt control device 20 via the motor drive control device. The motor drive control device can control forward rotation, reverse rotation, torque adjustment (current adjustment of the constant current circuit) or no load (circuit interruption) of the motor 61. For example, a PWM control circuit, an H bridge circuit, a comparator (opamp) constant current circuit, etc. can be used. By using such a motor drive control device, it is possible to apply a constant torque regardless of the withdrawal amount and the withdrawal speed of the webbing 41.

Further, a pretensioner mechanism 70 including a ring gear 71, a case 72, a ball 73, a gas generator (not shown), etc. is disposed on the axially outer side of the driven gear 64. Specifically, the ring gear 71 is attached to the driven gear 64 coaxially with the spool 51, and a plurality of balls 73 are annularly arranged in the case 72. Then, the pretensioner mechanism 70 pushes out the plurality of balls 73 by explosively driving the gas generator at the time of collision of the vehicle 10, and rotates the ring gear 71 by the pushing force of the plurality of pushed balls 73. Thus, the spool 51 is instantly rotated in the retracting direction to wind up the webbing 41 and remove the slack of the webbing 41.

Although the power transmission mechanism having the above-described configuration is illustrated here, another known configuration may be used as the power transmission mechanism. In addition, although the pretensioner mechanism 70 having the above-described configuration is illustrated here, other known configurations may be used as the pretensioner mechanism 70.

Next, the operation of the seat belt device of the present embodiment will be described separately for normal time and before collision and for collision and after collision.

(Normal time and before collision)
When the occupant 11 gets into the vehicle 10 and pulls out the webbing 41 from the initial position for wearing the seat belt, the seat belt control device 20 keeps the motor 61 in a stopped state (no-load state). Therefore, the occupant 11 can easily pull out the webbing 41.

When the tongue of the webbing 41 is attached to the buckle (both not shown), the seatbelt control device 20 detects the ON state of the switch provided on the buckle and drives the motor 61 in the forward rotation direction to move the webbing 41. It is rewound by a predetermined amount. Thereby, the slack of the seat belt can be removed.

When the tongue of the webbing 41 is removed from the buckle, the seatbelt control device 20 detects the off state of the switch provided on the buckle, drives the motor 61 in the forward rotation direction, and rewinds the webbing 41 to the initial position. ing. As a result, the webbing 41 is quickly and surely rewound, and it is possible to assist when attaching and detaching the seat belt.

When the seat belt is worn, the vehicle information sensor of the sensor unit 30 detects that an emergency action such as a sudden braking or a sharp turn has occurred, and the collision prediction sensor of the sensor unit 30 detects a collision object. Then, when a collision is predicted, the seat belt control device 20 drives the motor 61 in the forward rotation direction to rewind the webbing 41 by a predetermined amount. As a result, it is possible to notify the occupant 11 of the danger and to optimize the posture of the occupant 11 when wearing the seat belt. Then, if a collision occurs thereafter, the occupant 11 is properly restrained, so that the occupant 11 can be reliably protected.

(At and after collision)
When a large deceleration is applied to the vehicle 10 at the time of a collision, the vehicle body acceleration detection unit 57 detects the rapid deceleration of the vehicle 10 and the ELR wheel lock member 58 blocks the rotation of the ELR wheel 53. At this time, the occupant 11 tries to move relative to the vehicle body due to inertia, and the kinetic energy acts on the webbing 41 that restrains the occupant 11, and a pull-out load is applied to the webbing 41.

When the withdrawal load is applied to the webbing 41 while the ELR wheel 53 is prevented from rotating, this load is transmitted to the lock wheel 52 via the spool 51 and the torsion bar 54, and the lock wheel 52 is pulled out to the ELR wheel. Relative rotation force of the lock wheel 52 is generated, and the lock wheel lock member 56 prevents the lock wheel 52 from rotating.

In this way, when the rotation of the lock wheel 52 in the pull-out direction is blocked, one end of the torsion bar 54 supported by the lock wheel 52 is blocked from rotating, while the end of the torsion bar 54 on the end 51a side of the spool 51 is blocked. The other end side that is supported maintains a rotatable state. Therefore, when a larger pull-out load is applied to the webbing 41 while the ELR wheel 53 and the lock wheel 52 are prevented from rotating, this load becomes a torque via the spool 51 and is transmitted to the torsion bar 54 and the torsion bar 54. Begins to twist.

When the torsion bar 54 begins to twist, the spool 51 rotates in the pull-out direction, and at the same time, a force due to the torsional deformation of the torsion bar 54 acts on the rotation of the spool 51 in the pull-out direction. It is the limit value for the withdrawal load required to withdraw.

At the time of a collision, it is necessary to properly set the upper limit value of the withdrawal load that is the operating load of the force limiter. A belt load is a force required to pull out the webbing 41. The belt load Fb is normally a load Ft due to the torsional deformation of the torsion bar 54, but the load Ft is constant. It is the power of and cannot be flexibly set. Therefore, in this embodiment, by using the load Fm due to the torque of the motor 61 in addition to the load Ft, the belt load Fb (=load Ft±load Fm) is flexibly set, and the optimum belt load Fb is obtained. I am trying. In other words, the upper limit value of the withdrawal load (belt load Fb) at the time of collision can be increased or decreased with respect to the withdrawal load limit value (load Ft).

Specifically, at the time of a collision, the seat belt control device 20 controls the motor 61, drives the motor 61 in the forward rotation direction or the reverse rotation direction, and adjusts the torque applied to the spool 51 to adjust the pull-in direction or the pull-out direction. It is controlled so that the directional load Fm is applied. For example, in FIG. 3, the seat belt control device 20 drives the motor 61 in the forward rotation direction to control the load Fm in the retracting direction. Accordingly, the belt load Fb=the load Ft+the load Fm can be set, and the belt load Fb larger than the load Ft due to the torsional deformation of the torsion bar 54 can be applied. In other words, the motor 61 applies a torque to the spool 51 to rotate it in the retracting direction of the webbing 41, thereby increasing the belt load Fb above the load Ft.

On the other hand, when the seat belt control device 20 drives the motor 61 in the reverse rotation direction, the load Fm in the pull-out direction is controlled by this. Accordingly, the belt load Fb=the load Ft−the load Fm can be set, and the load Fb smaller than the load Ft due to the torsional deformation of the torsion bar 54 can be applied. In other words, the motor 61 gives a torque to the spool 51 to rotate it in the pulling-out direction of the webbing 41, thereby reducing the belt load Fb below the load Ft.

When the seatbelt control device 20 sets the motor 61 in the unloaded state, that is, when the torque applied from the motor 61 to the spool 51 is unloaded, the belt load Fb=the load Ft is set. Therefore, the load Ft due to the torsional deformation of the torsion bar 54 is applied.

The control of the load Fm by the motor 61 is performed based on the information acquired by the sensor unit 30 described above. For example, when a weight detection device is provided as the occupant information sensor, the magnitude and positive/negative of the load Fm are set based on the acquired information on the weight of the occupant 11. Similarly, when the seat position detection device is provided as the occupant information sensor, the magnitude and positive/negative of the load Fm are set based on the acquired information on the seated position of the occupant 11. Similarly, when a vehicle speed detection device is provided as the vehicle information sensor, the magnitude and positive/negative of the load Fm are set based on the acquired information on the speed and the acceleration (deceleration).

In this way, by changing the belt load Fb according to the occupant and vehicle conditions, it is possible to control the optimum working load of the force limiter.

Furthermore, based on the information acquired by the sensor unit 30 described above, not only the magnitude or positive/negative of the load Fm by the motor 61 may be set, but also the timing or the duration of the action of the load Fm may be changed. For example, regarding the magnitude of the load Fm, positive/negative, timing of action, and duration, a plurality of setting values corresponding to the information acquired by the sensor unit 30 are set in advance, and the information acquired by the sensor unit 30 is taken into consideration. The optimum set value may be selected and set from a plurality of set values.

Next, a comparison between the conventional seatbelt device and the seatbelt device of this embodiment will be performed with reference to FIGS.

As shown in FIG. 4, the conventional seat belt with a motor has the main functions of removing the slack of the seat belt, assisting in attaching and detaching the seat belt, alerting the occupant of danger, and optimizing the occupant's posture during normal times and before a collision. Yes, the motor was not operated at the time of the collision and after the collision started, and the working load of the force limiter was not changed.

However, the seat belts with motors disclosed in Patent Documents 3 and 4 change the working load of the force limiter at the time of collision and after the collision starts, but the torque of the motor depends on the load due to the torsional deformation of the torsion bar. Was only added to the load. To explain this with reference to FIG. 5, the belt load Fb with respect to the belt withdrawal amount increases as the belt withdrawal amount increases, but after a certain belt withdrawal amount, the load Ft due to the torsional deformation of the torsion bar is increased. Alternatively, the load Fm due to the torque of the motor is simply added to the load Ft.

Further, the variable force limiter seat belts disclosed in Patent Documents 1 and 2 change the working load of the force limiter at the time of a collision and after the collision starts, as shown in FIG. Unlike an attached seat belt, it does not remove the slack of the seat belt, assist in attaching and detaching the seat belt, notify the occupant of a danger, and optimize the occupant's posture during normal times and before a collision. Further, also regarding the change of the operating load of the force limiter, only the load due to the torsional deformation of the torsion bar is added to the load due to the predetermined mechanism. To explain this with reference to FIG. 6, the belt load Fb with respect to the belt withdrawal amount increases as the belt withdrawal amount increases, but after a certain belt withdrawal amount, the load Ft due to the torsional deformation of the torsion bar is increased. Alternatively, the load Fe by a predetermined mechanism is simply added to the load Ft.

On the other hand, as shown in FIG. 4, the seatbelt device of the present embodiment performs removal of seatbelt slack, assistance in attaching/detaching the seatbelt, warning to the occupant, and optimization of the occupant's posture during normal operation and before collision. It is possible and also possible to change the working load of the force limiter during and after a collision. In this way, the range of functions is wider than that of the conventional seat belt.

In addition, in changing the operating load of the force limiter, not only the load Fm due to the torque of the motor 61 is added to the load Ft due to the torsional deformation of the torsion bar, but the load Fm can be subtracted. Explaining this with reference to FIG. 7, the belt load Fb with respect to the belt withdrawal amount increases as the belt withdrawal amount increases, but after a certain belt withdrawal amount, the load due to the torsional deformation of the torsion bar 54. Ft, the load Ft due to the torque of the motor 61 can be added to the load Ft, or the load Fm due to the torque of the motor 61 can be subtracted from the load Ft. That is, in the present embodiment, the motor 61 is rotated in the forward direction to add the load Fm to the load Ft, and the motor 61 is rotated in the reverse direction to subtract the load Fm from the load Ft to reduce the belt load Fb. be able to.

Furthermore, since the magnitude and the positive/negative of the load Fm itself due to the torque of the motor 61 can be arbitrarily changed, the belt load Fb corresponding to the belt withdrawal amount can be flexibly changed. For example, as shown in FIG. 7, after the belt load Fb is set to the load Ft+the load Fm, when the belt withdrawal amount becomes a certain amount, the belt load Fb is returned to the load Ft, or the belt load Fb is further changed to the load Ft−. It may be lowered to the load Fm. Further, after the belt load Fb is set to the load Ft−the load Fm, when the belt withdrawal amount becomes a certain amount, the belt load Fb is returned to the load Ft, or the belt load Fb is increased to the load Ft+the load Fm. Is also good. In this way, the increase/decrease of the belt load Fb itself can be arbitrarily changed.

In the seat belt with the motor shown in Patent Documents 3 and 4, the withdrawal speed of the webbing is detected, and only the reaction force with respect to the withdrawal direction is adjusted by the motor to determine the belt load Fb. Therefore, as shown in FIG. 5, the belt load Fb is lower than the load Ft, which is only the load Ft due to the torsional deformation of the torsion bar, or the load Ft due to the torque of the motor. The load could not be set.

Also in the variable force limiter seat belts disclosed in Patent Documents 1 and 2, as shown in FIG. 6, the belt load Fb is the load Ft due to the torsional deformation of the torsion bar, or the load Ft is a predetermined value. Only the load Fe by the mechanism was added, and a load lower than the load Ft could not be set. Further, in the variable force limiter seat belts disclosed in Patent Documents 1 and 2, there is little freedom in changing the belt load Fb, and as shown in FIG. 6, the belt load Fb is changed from the state of the load Ft+the load Fe to the load Ft. After returning, the belt load Fb could not be changed.

On the other hand, the seat belt device of the present embodiment is structurally a seat belt with a motor, but according to the occupant, vehicle conditions, etc., the magnitude or positive/negative of the load Fm by the motor 61 is set, The belt load Fb (=load Ft±load Fm) is controlled, and unlike the seat belts described in Patent Documents 1 to 4, a load lower than the load Ft due to the torsional deformation of the torsion bar 54 can be set.

Further, in the seat belt device of the present embodiment, the belt load Fb is controlled by setting the timing and duration for which the load Fm is applied according to the occupant, vehicle condition, and the like. As described above, the seat belt device according to the present embodiment can reduce the belt load Fb as shown in FIG. 7 in accordance with various situations of the occupant and the vehicle, as compared with the seat belts described in Patent Documents 1 to 4. Since the control is performed, the range of adjustment amount of the belt load Fb viewed from the occupant 11 is increased and various controls can be performed.

The seat belt device according to the present invention is suitable for vehicles such as automobiles.

20 Seatbelt control device 30 Sensor part 40 Seatbelt device body 41 Webbing 50 Retractor 51 Spool 54 Torsion bar 61 Motor

Claims (3)

Webbing to restrain the occupant to the vehicle seat,
A spool that winds the webbing and rotates so that it can be pulled out,
A rotation blocking mechanism that blocks the rotation of the spool at the time of the collision of the vehicle and prohibits the withdrawal of the webbing,
A load limiting mechanism that allows the spool to rotate when a withdrawal load equal to or more than a limit value acts on the spool in the webbing withdrawing direction while the spool is prevented from rotating,
A motor that applies a torque to the spool so as to rotate the webbing in a winding direction or a drawing direction,
Control means for controlling the motor at the time of the collision and adjusting the torque applied to the spool,
A seat belt device, wherein an upper limit value of a pull-out load for pulling out the webbing at the time of the collision can be set to be larger or smaller than the limit value. The seat belt device according to claim 1,
The control means increases the upper limit value of the pull-out load above the limit value by applying a torque for rotating the spool in the winding direction of the webbing to the spool by the motor. On the other hand, by applying a torque to rotate the webbing in the pull-out direction, the upper limit value of the pull-out load is reduced below the limit value, and the torque of the motor is unloaded, whereby the upper limit value of the pull-out load is set. Is set to the limit value. The seat belt device according to claim 1 or 2,
A sensor for acquiring information on at least one of the occupant and the vehicle,
The seat belt device according to claim 1, wherein the control unit determines a rotation direction of the motor, a magnitude of a torque to be applied, an operation timing and a duration based on the information acquired by the sensor.

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