JP2010023614A - Vehicular seatbelt device and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular seat belt device capable of reliably restraining an occupant to a seat without giving any sense of incongruity to the occupant, and a control method thereof. <P>SOLUTION: The vehicular seat belt device is provided with: a clutch 20 which connects a motor 10 to a belt reel 12 under the rotational torque of the motor 10; a standby current control means 42 which conducts the low current for maintaining the clutch 20 in a connected state to the motor 10 when a vehicle state detection means 40 detects any instable state; and a holding current control means 43 which starts the control when the rotational position of the belt reel 12 is displaced in the webbing take-up direction over the permissible deviation amount from the target position during the current control by the standby current control means 42, and controls the conduction quantity of the motor 10 so that the rotational position of the belt reel 12 is maintained within a range of the permissible deviation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seat belt device for restraining an occupant seated on a vehicle seat by webbing and a control method thereof.

In recent years, as a seat belt device, one that pulls in webbing by a motor in an emergency has been developed (for example, see Patent Document 1).
This seat belt device includes a motor for pulling in webbing, vehicle state detection means such as an acceleration sensor for detecting an emergency state of the vehicle, and a controller for receiving a detection signal from the vehicle state detection means and controlling an energization current of the motor. In addition, when the vehicle state detection means detects an emergency state, the motor is instantaneously driven by the control of the controller, and the webbing is drawn to a position where the occupant can be reliably restrained.
JP 2004-224263 A

By the way, when the vehicle turns or decelerates, the upper body of the occupant seated on the seat may be swung from side to side or back and forth, and it is desired to suppress the deflection of the upper body by the seat belt device.
On the other hand, in the conventional seat belt device, since the webbing is pulled in by the motor only in an emergency, the occupant restraint cannot be obtained when the vehicle turns or decelerates.

In order to cope with this, a sensor that detects an unstable state such as when the vehicle is turning may be provided, and the motor may be driven when the sensor detects an unstable state. If there is a sudden take-up, the passenger feels uncomfortable.
That is, for example, when the occupant is swung left and right when the vehicle is turning, if the webbing is suddenly pulled in by the motor, the tension of the webbing that suddenly rises strongly tightens the occupant. Shock is transmitted.

  Accordingly, the present invention provides a vehicle seat belt device that can reliably restrain an occupant to a seat without causing the occupant to feel a sense of incongruity even in a situation where the occupant seated on the seat is swung from side to side or back and forth. Is to provide a method.

The invention according to claim 1, which solves the above problem, is a belt reel (e.g., in an embodiment described later) on which a webbing (e.g., a webbing 5 in an embodiment described later) for restraining an occupant seated on the seat is wound. A belt reel 12), a motor for transmitting a driving force to the belt reel (for example, a motor 10 in an embodiment described later), and the motor and belt receiving a rotational torque equal to or greater than a set value in the webbing winding direction of the motor. A clutch for maintaining the reel in a connected state (for example, a clutch 20 in an embodiment described later), a vehicle state detecting means for detecting a vehicle state (for example, a vehicle state detecting means 40 in an embodiment described later), and the belt reel Position detecting means (for example, a rotation sensor 11 in an embodiment described later) for detecting the rotational position of In a seat belt device for a vehicle that controls an energization amount of the motor based on a detection result of the position detection unit when the vehicle state detection unit detects an unstable state, the vehicle state detection unit detects the unstable state. A standby current control means (for example, a standby current control means 42 in an embodiment to be described later) that supplies a low current that can maintain the clutch in a connected state to the motor, and during the current control by the standby current control means In addition, control is started when the rotational position of the belt reel exceeds the allowable deviation from the target position and is displaced in the webbing pull-out direction, so that the rotational position of the belt reel is maintained within the allowable deviation range. A holding current control unit (for example, a holding current control unit 43 in an embodiment described later) for controlling the energization amount of the motor is provided.
In the case of the present invention, when the vehicle state detecting means detects an unstable state due to turning of the vehicle or the like, the standby current control means energizes the motor with a low current that can maintain the clutch in the connected state. As a result, the motor and the belt reel are maintained in a connected state, and rotational resistance on the motor side is applied to the belt reel. From this state, for example, when the upper body of the occupant moves due to centrifugal force or the like, the webbing is pulled, and the belt reel is rotationally displaced in the webbing pull-out direction. At this time, if the rotational position of the belt reel is displaced beyond the allowable deviation from the target position, the control by the holding current control means is started so that the rotational position of the belt reel is maintained within the allowable deviation range. The amount of current supplied to the motor is controlled. As a result, the motor continues to be energized by adding a current amount corresponding to the webbing extraction amount to the base current in the standby current control means.

According to a second aspect of the present invention, in the vehicle seat belt device according to the first aspect, the lower limit energization amount in the control by the holding current control means is set to a low current similar to the standby current control means. It is characterized by.
As a result, even after shifting to the control by the holding current control means, the lower limit energization amount becomes a low current that can maintain the clutch in the engaged state, so that the rapid restraining force after the rotation in the retracting direction of the belt reel is stopped. There will be no disconnection, and there will be no sudden increase in binding force even during re-retraction.

According to a third aspect of the present invention, in the vehicle seat belt device according to the first or second aspect, an emergency winding for controlling an energization amount to the motor so that the rotational position of the belt reel is displaced to the emergency winding position. Take-up control means (for example, emergency winding control means 44 in an embodiment described later) is provided, and when the vehicle state detection means detects an emergency state, current control by the standby current control means and holding current control means is avoided. Thus, the current control by the emergency winding control means is started.
As a result, in the event of an emergency, the control by the emergency winding control means is preferentially executed, and the belt reel is quickly rotationally displaced to the emergency winding position.

  According to a fourth aspect of the present invention, there is provided a belt reel on which a webbing for restraining an occupant seated on a seat is wound, a motor for transmitting a driving force to the belt reel, and a set value in a webbing take-up direction of the motor. A clutch for maintaining the motor and the belt reel in a connected state in response to the rotational torque of the vehicle, vehicle state detecting means for detecting the state of the vehicle, and position detecting means for detecting the rotational position of the belt reel, In the vehicle seat belt device control method for controlling the energization amount of the motor based on the detection result of the position detection unit when the vehicle state detection unit detects an unstable state, the vehicle state detection unit is unstable. When a state is detected, a step of energizing the motor with a low current that can maintain the clutch in a connected state (for example, a step in an embodiment described later). S116), the step of monitoring the rotational position of the belt reel during energization and comparing it with the target position (for example, step 104 in the embodiment described later), and the rotational position of the belt reel from the target position. A step of increasing the energization amount of the motor so that the amount of current is larger than the amount of current that can maintain the clutch in the engaged state when it is displaced in the webbing pull-out direction beyond the deviation allowance of Step S110) in the embodiment.

According to a fifth aspect of the present invention, in the method for controlling a seat belt device for a vehicle according to the fourth aspect, when the rotational position of the belt reel is maintained in the vicinity of the target position over a predetermined time, the The amount of current supplied to the motor is reduced to the low current that can maintain the clutch in a connected state.
In this case, the energizing current is not reduced to a low current until the belt reel rotation position is maintained in the vicinity of the target position for a predetermined time. Power is maintained.

According to a sixth aspect of the present invention, in the method for controlling a seatbelt apparatus for a vehicle according to the fourth or fifth aspect, the step of changing the allowance for deviation from the target position (for example, step S107 in an embodiment described later, S117), and when the motor is energized with a low current that can maintain the clutch in the engaged state, a deviation allowance when increasing the amount of energization to the motor (for example, a deviation allowance Xth2 in an embodiment described later) ) Larger than the allowable deviation (for example, the allowable deviation Xth1 in an embodiment described later).
As a result, in a situation where the motor is controlled with a low current that can maintain the clutch in a connected state with little vibration of the occupant's upper body, the allowance for deviation is set large, and the frequency of changing the current amount is suppressed. Further, in a situation where the upper body shake of the occupant increases and the energization amount to the motor increases, the deviation allowance is set small and the current amount is frequently adjusted.

According to the first and fourth aspects of the present invention, when an unstable state is detected by the vehicle state detecting means, the motor energizing current is controlled at a low current that can maintain the clutch in the engaged state, and then the webbing Since energization is continued in the form of adding an amount of current corresponding to the amount of pull-out, movement of the occupant can be quickly and reliably suppressed without giving the occupant a sense of discomfort due to a sudden increase in torque.
In addition, according to the present invention, since the energization current of the motor is controlled at a low current that can maintain the clutch in the engaged state, when the belt reel is rotated in the retracting direction together with the occupant movement, a response is given later. It is possible to quickly suppress the occupant's shake without excessively accelerating it, and to reduce the maximum driving force when restraining the occupant and to reduce the sudden feeling of operation.
Furthermore, if the occupant does not actually move after an unstable state is detected by the vehicle state detection means, the restraining force of the webbing is not increased, so unnecessary comfort is eliminated and passenger comfort is improved. In addition, the power consumption can be reduced.

According to the second and fifth aspects of the present invention, there is no sudden loss of the restraining force after the rotation of the belt reel in the retracting direction stops, and no rapid increase of the restraining force occurs during the re-retraction. , Passenger comfort can be further increased.
According to the fifth aspect of the present invention, the energizing current is not reduced to a low current unless the rotational position of the belt reel is maintained in the vicinity of the target position for a predetermined time. It can correspond to.

  According to the third aspect of the invention, since the control by the emergency winding control means is preferentially executed in an emergency, it is possible to realize quick passenger restraint by webbing.

  According to the sixth aspect of the present invention, in a situation where the upper body shake of the occupant is small, the deviation allowance is set to be large, so that the frequency of webbing by the motor is reduced and the comfort of the occupant is maintained. Therefore, in a situation where the upper body shake of the occupant is large, the allowance for deviation is set small, so that the frequency of webbing can be increased and the occupant can be more stably held on the seat.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an overall schematic configuration of a seat belt device 1 according to the present invention. In FIG. 1, reference numeral 2 denotes a seat on which an occupant 3 is seated. The seat belt device 1 of this embodiment is a so-called three-point seat belt device, and a webbing 5 is drawn upward from a retractor 4 attached to a center pillar (not shown), and the webbing 5 is supported on the upper side of the center pillar. The tip of the webbing 5 is fixed to the vehicle body floor via an outer anchor 7 near the outside of the passenger compartment of the seat 2. A tongue plate 8 is inserted between the through anchor 6 and the outer anchor 7 of the webbing 5, and the tongue plate 8 can be attached to and detached from the buckle 9 fixed to the vehicle body floor of the seat 2 on the inner side of the vehicle body. It has become.
The webbing 5 is wound around the retractor 4 in the initial state, and the occupant 3 pulls it out by hand to fix the tongue plate 8 to the buckle 9, thereby restraining the chest and abdomen mainly of the occupant 3 with respect to the seat 2. To do. Further, the seat belt device 1 automatically retracts the webbing 5 by the electric motor 10 in an emergency or when the behavior change of the vehicle is large.

  As shown in FIG. 2, the retractor 4 has a webbing 5 wound around a belt reel 12 rotatably supported by a casing (not shown), and a shaft of the belt reel 12 projects from one end side of the casing. . The belt reel 12 is connected to the rotating shaft 10 a of the motor 10 via a power transmission mechanism 13 so as to be interlocked. The power transmission mechanism 13 decelerates the rotation of the motor 10 and transmits it to the belt reel 12. Further, the retractor 4 is provided with a winding spring (not shown) that urges the belt reel 12 in the webbing winding direction. When the belt reel 12 and the motor 10 are separated by a clutch 20 described later, the retractor 4 Tension acts on the webbing 5.

Further, the retractor 4 is provided with a rotation sensor 11 (position detection means) for detecting the rotation position of the belt reel 12. The rotation sensor 11 includes, for example, a magnetic disk in which different magnetic poles are alternately magnetized along the circumferential direction and rotates integrally with the belt reel 12, and a pair disposed in the vicinity of the outer peripheral edge of the magnetic disk. And a sensor circuit for processing a detection signal of the Hall element, and a pulse signal processed by the sensor circuit is output to the controller 21.
In this case, the pulse signal input from the sensor circuit to the controller 21 according to the rotation of the belt reel 12 is used to detect the rotation amount, rotation speed, rotation direction, and the like of the belt reel 12. That is, in the controller 21, the rotation amount of the belt reel 12 (the amount of webbing 5 pulled out) is detected by counting the pulse signal, and the rotation speed of the belt reel 12 is calculated by calculating the change speed (frequency) of the pulse signal. The webbing 5 winding / drawing speed is obtained, and the rotation direction of the belt reel 12 is detected by comparing the rising edges of the waveforms of both pulse signals.

3 to 5 show a specific configuration of the power transmission mechanism 13.
In the power transmission mechanism 13, a sun gear 14 is integrally coupled to an external tooth 15 for driving input, and a carrier 17 that supports a plurality of planetary gears 16 is coupled to the shaft of the belt reel 12. A plurality of ratchet teeth 19 (see FIG. 4) are formed on the outer peripheral side of the ring gear 18 meshed with the planetary gear 16, and the ratchet teeth 19 constitute a part of the clutch 20. The clutch 20 appropriately disconnects the power transmission system between the motor 10 and the belt reel 12 by controlling the driving force of the motor 10 by the controller 21.

  The motor-side power transmission system 22 of the power transmission mechanism 13 is capable of rotating coaxially and integrally with the first connect gear 23 having a small diameter that is always meshed with the external teeth 15 that are integral with the sun gear 14. A large-diameter second connect gear 24, and first and second idler gears 26, 27 that are between the second connect gear 24 and the motor gear 25 (integrated with the rotating shaft 10a of the motor 10) and are always meshed so as to be able to transmit power. And is composed of. The driving force in the forward rotation direction of the motor 10 is transmitted to the second and first connect gears 24 and 23 through the gears 25, 27 and 26 as indicated by solid arrows in FIG. After being transmitted to the sun gear 14, it is transmitted to the belt reel 12 through the planetary gear 16 and the carrier 17. The driving force in the forward rotation direction of the motor 10 rotates the belt reel 12 in the direction in which the webbing 5 is pulled. However, the driving force transmitted from the sun gear 14 to the planetary gear 16 is all transmitted to the carrier 17 side as described above when the ring gear 18 is fixed. However, when the ring gear 14 is free to rotate, the planetary gear is transmitted. The ring gear 18 is idled by 16 rotations. The clutch 20 controls the locking and unlocking of the rotation of the ring gear 14 to turn on / off the transmission of the motor driving force to the belt reel 12 (carrier 17).

Here, the clutch 20 will be described with reference to FIGS.
The clutch 20 is rotatably supported by a casing (not shown), and can be engaged with a pawl 29 having a locking claw 28 at the tip, a clutch spring 30 for operating the pawl 29, and a locking claw 28 of the pawl 29. And the ratchet teeth 19 of the ring gear 14, and when the pawl 29 is operated in the direction of the ratchet teeth 19, the locking claw 28 abuts against a surface substantially orthogonal to the inclined surface of the ratchet teeth 19, Lock the rotation in one direction.

  In addition, the clutch spring 30 is bent in a circular arc shape at the base portion side, and the bent portion 31 is locked in a state of being wound around the outer periphery of the shaft portion of the first connect gear 23. The tip of the clutch spring 30 extends in the direction of the pawl 29 and engages with the operation window 32 of the pawl 29. The curved portion 31 of the clutch spring 30 is engaged with the shaft portion of the first connect gear 23 by friction, and when a torque greater than a set value acts between the first connect gear 23 and the first connect gear 23, Slips between the two.

Therefore, in the clutch 20, when the motor 10 rotates in the forward rotation direction (see the solid line arrow in FIG. 4), the clutch spring 30 changes from the position shown by the solid line in FIG. 5 to the position shown by the chain line. As shown in FIG. 4, the pawls 29 of the pawl 29 mesh with the ratchet teeth 19 to lock the rotation of the ring gear 18. At this time, the ratchet teeth 19 can reliably lock the rotation of the ring gear 18 in one direction, but the ratchet teeth 19 push up the locking claws 28 even when the ring gear 18 attempts to rotate in the reverse direction. A certain level of power is required. For this reason, the clutch spring 30 imparts a certain level of resistance to the reverse rotation of the ring gear 18.
When the rotation of the ring gear 18 is thus locked, all the rotational force transmitted to the sun gear 14 as described above is transmitted to the belt reel 12 as the rotation of the carrier 17 (clutch-on state).

On the other hand, when the motor 10 rotates in the reverse direction from the clutch-on state, the first connect gear 23 rotates as indicated by the dotted line arrow in FIG. 4 to rotate the clutch spring 30 as indicated by the solid line in FIG. As a result, the pawl 28 of the pawl 29 is pulled away from the ratchet teeth 19 and the lock of the ring gear 18 is released.
When the lock of the ring gear 18 is released in this way, the rotational force transmitted to the sun gear 14 rotates the planetary gear 16 as described above, and at this time the ring gear 18 is idled to drive the carrier 17 (belt reel 12). Is not transmitted (clutch off state).

By the way, in addition to the rotation sensor 11, as shown in FIG. 2, the controller 21 is a sign that the upper body of the occupant is swung from side to side or back and forth when the vehicle is relatively in an unstable state, for example, when the vehicle is turning or decelerating. The first vehicle state detection means 40 for detecting the state to become and the second vehicle state detection means 41 for detecting that the vehicle is facing an emergency state (extremely unstable state) are connected. Yes.
As the first vehicle state detection means 40, for example, a lateral acceleration sensor, a longitudinal acceleration sensor, a wheel slip sensor, or the like is used. Further, as the first vehicle state detection means 40, for example, an unstable state is predicted using the vehicle speed and the steering angle, a vehicle navigation map information is predicted, or a radar front detection information is predicted. It is possible to employ a device that predicts from a differential value of acceleration acting on the vehicle, and a device that makes a judgment based on these values.
Further, as the second vehicle state detection means 41, a determination is made based on whether the VSA is activated and the yaw rate or slip angle is a predetermined value or more, or the lateral acceleration sensor or the longitudinal acceleration sensor is a predetermined value or more. Those that are judged based on a certain thing can be adopted.

The controller 21 also includes a standby current control means 42 for energizing the motor 10 with a low current Iw that can maintain the clutch 20 in the connected state (almost the minimum current that can be maintained in the connected state), and a low current by the standby current control means 42. During the control with the current Iw, when the rotational position of the belt reel 12 is displaced from the target position in the webbing pull-out direction beyond the allowable deviation Xth, the rotational position of the belt reel 12 is maintained within the allowable deviation Xth. Holding current control means 43 for controlling the energization amount of the motor 10 and emergency winding control means for controlling the energization amount for the motor 10 so that the rotational position of the belt reel 12 is quickly displaced to the emergency winding position. 44, vehicle state determination means 45 for determining the vehicle state based on the output signals of the first and second vehicle state detection means 40, 41, and the rotation of the belt reel 12. Position and the amount of deviation between the target position is provided with a deviation amount determining means 46 determines whether the range of deviation allowable margin Xth, the.
The vehicle state determination means 45 selects the control of the motor 10 by the standby current control means 42 when it is determined that the vehicle is in a relatively light and unstable state, and when it is determined that the vehicle is in an emergency state, the emergency winding The control of the motor 10 by the take control means 44 is selected. Further, when the deviation amount determination means 46 determines that the deviation amount is within the range of the deviation allowable allowance Xth, the motor control by the standby current control means 42 is selected, and the deviation amount is not within the range of the allowable deviation allowance Xth. Is determined, the motor control by the holding current control means 43 is selected.

In addition, the following (a)-(c) is employable as the determination method of the low electric current Iw which can maintain the clutch 20 in a connection state, for example.
(A) The optimum current (minimum starting current that can maintain the clutch 20 in the engaged state) is stored in advance under the environment (voltage, temperature, humidity, etc.) used, and the value is set as the low current Iw. Use.
(B) Based on information from the rotation sensor 11, it is detected that the webbing 5 (belt reel 12) has moved slightly, and the current value at that time is used as the low current Iw.
(C) Either (a) or (b) is selected and used according to the situation.

Further, for example, the following (d) to (f) can be adopted for the current control by the holding current control means 43 when the rotational position of the belt reel 12 exceeds the allowable deviation Xth.
(D) The energization amount is linearly increased with respect to the increase in the displacement of the belt reel 12.
(E) The energization amount is increased nonlinearly with respect to the increase in displacement of the belt reel 12.
(F) Either (d) or (e) is selected according to the situation.

Hereinafter, the control by the controller 21 of the seat belt apparatus 1 will be described with reference to the flowcharts of FIGS.
FIG. 6 shows the main flow of control.
In step S1 of the main flow, the winding position of the belt reel 12 during traveling is always measured, and the winding reference position is set using the average value of the measured values.
In step S2, information such as the vehicle state detection means 40, 41 and the rotation sensor 11 is read.
In step S3, it is determined whether or not the vehicle is in an emergency state. If NO, the process proceeds to step S4. If YES, the process proceeds to emergency process S8.
In step S4, it is determined whether or not the vehicle is in a slight unstable state. If YES, the process proceeds to normal time control S6, and if NO, the process returns.
After completing the normal control S6, the process proceeds to step S7 to determine again whether the vehicle is in an emergency state. If YES, the process proceeds to the emergency process S8 and then proceeds to step S9. In that case, the process proceeds to step S9 as it is. In step S9, it is determined whether or not the vehicle is in a stable state. If YES, the process returns. If NO, the process returns to step S2.
That is, in this main flow, the determination as to whether the vehicle is in an emergency state and the emergency process S8 are performed with priority, and the normal process S6 is performed when it is determined that the vehicle is not in an emergency state.

FIG. 7 shows a flow of the normal time control S6.
In the normal control, first, the target position X1 (target rotational position) of the belt reel 12 is set in step S101. The target position X1 is set to, for example, the same value as the reference position or a value obtained by adding a value corresponding to the traveling state of the vehicle to the reference position.
In the next step S102, the motor 10 is energized with a low current Iw that can maintain the clutch in the engaged state, and a standby flag serving as an indicator that the motor 10 is operating with the low current Iw is turned on. The deviation allowance Xth between the current position X (current rotational position) of 12 and the target position X1 is set to Xth1. Note that there are two types of values set for the deviation allowance Xth, Xth1 (for example, 10 to 20 mm) and Xth2 (for example, 5 to 6 mm), and the larger value Xth1 is used here. In addition, if the low current Iw energized to the motor 10 in step S102 is set to a value that allows the belt reel 12 to be wound with a weak force when the webbing 5 is in an almost no load state, the slack of the webbing 5 is reduced. It can be eliminated at this stage.

  In the next step S103, it is determined whether or not the current position X of the belt reel 12 is not equal to the target position X1. If YES, the process proceeds to step S104. If NO, the process proceeds to step S105. In step S104, it is determined whether or not the absolute value of the difference between the target position X1 and the current position X is larger than the allowable deviation Xth. If the absolute value is larger than the allowable deviation Xth, the process proceeds to step S106. Advances to step S105. That is, when the current position X is within the range of the deviation allowance Xth, the process proceeds to step S105, and otherwise, the process proceeds to step S106.

In step S106, it is determined whether or not the current position X of the belt reel 12 is smaller than the target position X1, that is, whether the webbing 5 is not sufficiently wound or is excessively wound. If not (YES), the process proceeds to step S107, and if excessively wound (NO), the process proceeds to step S108.
If the process proceeds to step S107, the standby flag is turned OFF, and the deviation allowance Xth is set to Xth2 having a small value, and then the process proceeds to step S109.
In step S109, it is determined whether or not the upper limit value Iupper_limit is not exceeded when the minute current ΔI is added to the current energization amount I for the motor 10. If YES, the process proceeds to step S110 and the energization amount of the motor 10 is determined. Is increased by ΔI before proceeding to step S111. If NO, the process proceeds directly to step S111.
In step S108, it is determined whether or not the clutch 20 is larger than the low current Iw that can maintain the connected state when the minute current ΔI is subtracted from the current energization amount I to the motor 10. If YES, Then, the process proceeds to step S112, and the energization amount of the motor 10 is subtracted by ΔI, and then the process proceeds to step S111. If NO, the energization amount of the motor 10 is set to the low current Iw in step S113 and then the process proceeds to step S111. .
In step S111, it is determined whether or not the vehicle is in an emergency state, and in the case of YES, the normal time control S6 is terminated and the process proceeds to the subsequent emergency control S8. If NO in step S111, it is determined in next step S114 whether the vehicle is in an unstable state. If YES here, the process returns to step S103, and if NO, normal time is determined. Control S6 ends.

  The series of processing from step S106 to step S111 described here is processing for increasing / decreasing the energization amount when the rotational position X of the belt reel 12 is out of the allowable deviation Xth, and the increasing energization amount is the upper limit. When the value Iupper_limit is exceeded, further increase in current is stopped, and when the energization amount to be decreased is lower than the low current Iw, the energization amount is fixed to the low current Iw.

  This series of processing is mainly performed when the belt reel 12 is moved by the shake of the occupant's upper body during energization control (standby current control) at a low current Iw from step S105 to step S111 described later. When the displacement exceeds the allowable deviation allowance Xth, the energization current is controlled so that the displacement is returned to the allowable deviation allowance Xth, which corresponds to the function of the holding current control means 43 described above. In step S107, the deviation allowance Xth is set to Xth2 having a small value. Therefore, after shifting to the holding current control once, the criterion in step S104 becomes strict, and a slight change in the amount of withdrawal of the webbing 5 occurs. On the other hand, the rotational position of the belt reel 12 is corrected.

On the other hand, if it is determined in step S103 or S104 that the current position X is within the range of the allowable deviation Xth and the process proceeds to step S105, it is determined whether or not the standby flag is OFF in step S105. In this case, the process proceeds to step S114 to turn on the standby flag and start the timer (t = 0), and then proceeds to step S111. When the process proceeds from step S106 to step S105 for the first time after the process of step S111 (holding current control), the process of step S114 is performed.
In step S105, if NO, the process proceeds to step S116 to determine whether or not the timer count time t has exceeded the predetermined time t1, and if YES, the process proceeds to step S117, and the energization amount of the motor 10 is determined. Is set to a low current Iw that can maintain the clutch 20 in the engaged state, and the deviation allowance Xth is set to Xth1 having a large value, and then the process proceeds to step S111. If NO in step S116, the process proceeds directly to step S111. That is, after passing through the processing (holding current control) from step S106 to step S111, the energization amount of the motor 14 is switched to the low current Iw after the elapse of the predetermined time t1.

  In step S117, the process of setting the energization amount of the motor 10 to the low current Iw corresponds to the function of the standby current control means 42 described above. In step S117, the deviation allowance Xth is set to Xth1, which has a large value. Therefore, after shifting to the standby current control once, the criterion in step S104 becomes loose, and the webbing 5 is slightly pulled out. This makes it difficult to shift to holding current control.

FIG. 8 shows the flow of emergency control S8.
In step S201 of emergency control, the target position X2 (target pull-in position) of the belt reel 12 is set, and the arrival flag serving as an index indicating that the rotational position of the belt reel 12 has once reached the target position X2 is turned OFF. Set to. The target position X2 is set to be capable of firmly restraining the occupant with the webbing 5, and has a value larger than the target position X1 in the normal control S6.
In subsequent step S202, it is determined whether or not the arrival flag is ON. If YES, the process proceeds to step S203, and if NO, the process proceeds to step S204. Since the arrival flag is set to OFF in step S201 for the first time when emergency control is started, the process proceeds to step S204.

In step S204, the motor 10 is energized with a preset initial value I0, and in the next step S205, it is determined whether or not the current position X of the belt reel 12 is equal to or greater than the target position X2. At this time, in the case of YES, the process proceeds to step S206 to turn on the arrival flag and then proceeds to step S211. In the case of NO, the process proceeds to step S211 as it is.
In step S211, it is determined whether or not the vehicle is in a stable state. If YES, the emergency control is terminated, and if NO, the process returns to step S202.
Accordingly, in step S205, the arrival flag remains OFF until the current position X reaches the target position X2, and the energization of the motor 10 at the initial value I0 is continued.

When the arrival flag is set to ON in step S206, the process proceeds from step S202 to step S203, and in step S203, it is determined whether or not the current position X is not equal to the target position X2. If YES, the process proceeds to step S207. If NO, the process proceeds to step S111.
In step S207, it is determined whether or not the difference between the current position X and the target position X2 is greater than or equal to a predetermined value. If YES, the process proceeds to step S208. If NO, the process proceeds to stop S211.
In step S208, it is determined whether or not the current position X is smaller than the target position X2. If YES (if smaller), the process proceeds to step S209, the energization amount is increased, and then the process proceeds to step S211. In the case of (if larger), the process proceeds to step S210 to decrease the energization amount and then proceeds to step S211.
Therefore, in the series of processing from step S203 to step S211, the energization of the motor 10 is performed so that the rotational position of the belt reel 12 is maintained after the rotational position (current position) of the belt reel 12 once reaches the target position. Control the amount.

As described above, in the seatbelt apparatus 1, when a slight unstable state is detected by the first vehicle state detection unit 40, the low current Iw that can maintain the clutch 20 in the engaged state by the standby current control unit 42. The energization current of the motor 10 is controlled to prepare for the subsequent movement of the occupant's body (step S117). That is, in this state, rotational resistance on the motor 10 side is applied to the belt reel 12 (webbing 5) via the clutch 20, and the external force acting on the webbing 5 can be countered with a certain level of force.
After that, when the upper body of the occupant actually moves left and right or back and forth, and the webbing 5 is pulled out beyond a certain amount (deviation allowance Xth) against the rotational resistance on the motor 10 side, the holding current control means The energizing current of the motor 10 is controlled by 43 so as to increase the energizing amount according to the displacement of the belt reel 12 (steps S106 to S111).

  In the case of this seat belt device 1, first, a low current Iw that can maintain the clutch 20 in a connected state is supplied so that a certain amount of resistance can be applied to the withdrawal of the webbing 5. When the belt reel 12 is pulled out due to the shake of the occupant's upper body, the energization is continued by adding a current amount corresponding to the displacement of the belt reel 12 to the base low current Iw. For this reason, when the upper body of the occupant is actually restrained by the webbing 5, the occupant is not given a sense of incongruity due to a sudden increase in torque (an impact due to a sudden increase in tension).

  Since the rotational resistance on the motor 10 side is applied to the belt reel 12 in advance before actually restraining the occupant, the upper body of the occupant can be shaken without excessively accelerating the response to the occupant's body movement. Since the maximum driving force when restraining the occupant can be reduced, it is possible to reduce the sudden feeling of operation.

  Further, in the case of the seat belt device 1, when a slight unstable behavior is once detected by the first vehicle state detection means 40 and the upper body of the occupant does not actually swing greatly, the motor 10 Since strong pulling of the webbing 5 is not performed, an unpleasant feeling is not given by applying unnecessary restraining force to the occupant, and power consumption in the motor 10 can be suppressed.

Further, in this seat belt device 1, when the motor 10 is controlled by the holding current control means 43, the lower limit energization amount is set to the low current Iw that can maintain the clutch 20 in the connected state. After the rotation of the reel 12 in the pull-in direction stops, there is no sudden loss of the binding force, and no rapid increase in the binding force occurs during the re-drawing. For this reason, a passenger | crew's comfort can be improved more.
In addition, the rotational position of the belt reel 12 is maintained in the vicinity of the target position X1 for a predetermined time or more from the control according to the drawing amount by the holding current control means 43 to the control at the low current Iw by the standby current control means 42. (Step S116), it is possible to respond quickly to the occupant's shake even in a situation where the occupant's upper body is shaken continuously after instantaneous stabilization and webbing. 5 can be suppressed and the impact can be reduced.

  Further, in the seatbelt device 1, the deviation allowance Xth is set to be large when the standby current control means 42 is controlled at the low current Iw, and the deviation allowance Xth is set at the time of control according to the drawing amount by the holding current control means 43. Therefore, in the situation where the upper body shake of the occupant is small, the restraint force can be applied less frequently to maintain the comfort of the occupant and Thus, it is possible to increase the frequency of applying the restraining force and reliably hold the occupant in a stable posture.

  In addition, the seat belt apparatus 1 includes an emergency winding unit 44 in addition to the standby current control unit 42 and the holding current control unit 43. When an emergency state is detected, the standby current control unit 42 and the holding current control unit 43 Since the control by the emergency winding means 44 is executed with priority, prompt occupant restraint can always be realized in an emergency.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary.

1 is a schematic configuration diagram of a seat belt device according to an embodiment of the present invention. The schematic block diagram of the retractor and controller of the seatbelt apparatus of the embodiment. The schematic block diagram of the retractor of the seatbelt apparatus of the embodiment. The schematic block diagram which looked at the power transmission system of the retractor of the embodiment from the front. The one part enlarged view of the power transmission system of the embodiment. The flowchart which shows the flow of control of the embodiment. The flowchart which shows the flow of control of the embodiment. The flowchart which shows the flow of control of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus 5 ... Webbing 10 ... Motor 11 ... Rotation sensor (position detection means)
DESCRIPTION OF SYMBOLS 12 ... Belt reel 20 ... Clutch 40 ... 1st vehicle state detection means (vehicle state detection means)
42 ... Standby current control means 43 ... Holding current control means 44 ... Emergency winding control means

Claims (6)

A belt reel on which a webbing that restrains an occupant seated on the seat is wound;
A motor for transmitting a driving force to the belt reel;
A clutch that receives a rotational torque equal to or greater than a set value of the webbing winding direction of the motor and maintains the motor and the belt reel in a connected state;
Vehicle state detection means for detecting the state of the vehicle;
Position detecting means for detecting the rotational position of the belt reel,
In the vehicle seat belt device that controls the energization amount of the motor based on the detection result of the position detection unit when the vehicle state detection unit detects an unstable state.
Standby current control means for energizing the motor with a low current that can maintain the clutch in a connected state when the vehicle state detection means detects an unstable state;
During the current control by the standby current control means, the control is started when the rotational position of the belt reel exceeds the allowable deviation from the target position and is displaced in the webbing pull-out direction. And a holding current control means for controlling the energization amount of the motor so as to be maintained within the range.   The vehicle seat belt device according to claim 1, wherein the lower limit energization amount in the control by the holding current control means is set to a low current similar to that of the standby current control means. Providing an emergency winding control means for controlling the energization amount to the motor so that the rotational position of the belt reel is displaced to the emergency winding position;
When the vehicle state detection unit detects an emergency state, current control by the emergency winding control unit is started by avoiding current control by the standby current control unit or holding current control unit. The vehicle seat belt device according to claim 1 or 2. A belt reel on which a webbing that restrains an occupant seated on the seat is wound;
A motor for transmitting a driving force to the belt reel;
A clutch that receives a rotational torque equal to or greater than a set value of the webbing winding direction of the motor and maintains the motor and the belt reel in a connected state;
Vehicle state detection means for detecting the state of the vehicle;
Position detecting means for detecting the rotational position of the belt reel,
In the control method of a seat belt device for a vehicle that controls the energization amount of the motor based on the detection result of the position detection unit when the vehicle state detection unit detects an unstable state.
Energizing the motor with a low current capable of maintaining the clutch in a connected state when the vehicle state detecting means detects an unstable state;
Monitoring the rotational position of the belt reel during energization and comparing it to a target position;
When the rotational position of the belt reel exceeds the allowance for deviation from the target position and is displaced in the webbing pull-out direction, the motor has a current amount larger than a current amount capable of maintaining the clutch in a connected state. Increasing the energization amount to
A control method for a seat belt device for a vehicle, comprising:   When the rotational position of the belt reel is maintained in the vicinity of the target position over a predetermined time, the energization amount to the motor is reduced to the low current that can maintain the clutch in a connected state. A method for controlling a seat belt device for a vehicle according to claim 5. Changing the allowance for deviation from the target position,
5. When the motor is supplied with a low current capable of maintaining the clutch in a connected state, a deviation allowance larger than a deviation allowance for increasing the energization amount to the motor is set. Or a control method for a seat belt device for a vehicle according to 5;

Images