JP5244484B2 - Vehicle seat belt device and control method thereof - Google Patents

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 a seat belt device mounted on a vehicle, a webbing for restraining an occupant is wound around a belt reel in a retractor, and is pulled out from the retractor when mounted. The seat belt device is provided with an emergency lock mechanism that mechanically locks the webbing drawer in an emergency. The drawer is locked to restrain the passenger to the seat.

  In recent years, a seat belt device has been devised that detects the state of a vehicle using an acceleration sensor, a yaw rate sensor, a brake switch, or the like, and controls the tension of the webbing according to the state of the vehicle (see, for example, Patent Document 1). .

The seat belt device includes a motor for retracting the webbing, a vehicle state detection device that detects the state of the vehicle, and a controller that receives the detection signal of the vehicle state detection device and controls the energization current of the motor. When the device detects turning of the vehicle, braking operation, rollover, or the like, the controller selects an energization current for the motor so as to obtain a webbing tension suitable for the vehicle state at that time.
JP 2004-291967 A

  However, in the case of this conventional seat belt device, since the energization current of the motor is controlled in accordance with the state of the vehicle, for example, when turning of the vehicle is detected by the vehicle state detection device, Energization is continued with a constant current value as a target. For this reason, when the energizing current setting is made with emphasis on the webbing take-up speed in the initial stage of removing the slack of the webbing, the tension of the webbing in the later stage of restraining the occupant increases, and the feeling of pressure given to the occupant Will become bigger. Conversely, when the energizing current is set with emphasis on relaxation of webbing tightening at the later stage, the webbing winding speed at the initial stage is insufficient.

Also, in this type of seat belt device, it has been studied to frequently detect the state of the vehicle in a short cycle and update the energization current of the motor each time.
However, even if the detection value is the same for the vehicle state, it is not possible to determine whether it is currently the webbing winding stage or the occupant restraint stage, so the vehicle current is frequently detected and the motor current is updated. Even so, it is difficult to achieve both quick winding at the webbing winding stage and reduction of the feeling of pressure at the passenger restraint stage.

  Therefore, the present invention is to provide a vehicle seat belt device and a method for controlling the same that can achieve both quick winding at the winding stage of the webbing and reduction of the feeling of pressure at the passenger restraining stage. is there.

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. In a vehicle seat belt apparatus including a clutch that maintains a reel in a connected state (for example, a clutch 20 in an embodiment described later), a vehicle state detection device that detects the state of the vehicle (for example, a lateral belt in an embodiment described later) The acceleration sensor 29 and the yaw rate sensor 31) and the motor status detection device based on the detection signal. Target current setting means (for example, target current setting means 34 in an embodiment to be described later) for periodically setting a target current to be supplied to the motor and the target current set by the target current setting means. Standard current control means for controlling the energization current (for example, standard current setting means 35 in the embodiment described later) and holding current control means for energizing the motor with a low current capable of maintaining the clutch in a connected state (for example, later described) According to the comparison result between the current target current set by the holding current control means 36), the target current setting means, and the average current value of the past target currents set by the target current setting means. the one current control selecting means for selecting one energization for energizing the holding current control means in the normal current control means (e.g., a current according to the embodiment described later And control selection means 37), characterized in that the provided.
Thus, when the vehicle state detection device detects a vehicle state that requires restraint by the seat belt, the target current setting means sets the target current based on the detection signal of the vehicle state detection device. The energization current of the motor is controlled by the standard current control means so as to coincide with the target current. The target current is set periodically by the target current setting means, and the current target current set by the target current setting means is compared with the average current value of the past target currents set by the target current setting means. In the current control selection means, for example, when the value of a constant multiple of the current target current is larger than the average current value of the past target current, the motor control by the standard current control means is selected and the current target current constant is selected. When the double value is smaller than the average current value of the past target current, the motor control by the holding current control means is selected. Therefore, in a situation where a change in the winding position of the belt reel is predicted to be large, motor control is performed by the standard current control means, and in a situation where a change in the winding position of the belt reel is predicted to be small, the holding is performed. Motor control is performed by the current control means.

According to a second aspect of the present invention, in the seat belt device for a vehicle according to the first aspect, the holding current control means is configured to perform the energization at a substantially minimum value that can maintain the clutch in a connected state. It is characterized in that energization is performed with an intermediate current value larger than the minimum value.
As a result, when the energization control of the motor shifts from the standard current control means to the holding current control means, the current value close to the target current is once lowered to the intermediate current value, and then to a substantially minimum value that can maintain the clutch in the connected state. Be lowered.

According to a third aspect of the invention, in the vehicle seat belt device according to the first or second aspect, when the current control is shifted from the holding current control means to the standard current control means, the current increase amount per time is regulated. It is characterized by being limited to a value or less.
As a result, when the current control is shifted from the holding current control means to the standard current control means, a sudden increase in the current supplied to the motor is regulated.

According to a fourth aspect of the present invention, in the seat belt device for a vehicle according to the third aspect, the restriction value is set so as to increase as the vehicle speed increases .
This makes it possible to increase the limits for increasing the speed of the current when the car speed is faster.

According to a fifth 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. And a clutch that maintains the motor and a belt reel in a connected state in response to a rotational torque of the vehicle, and a target current for energizing the motor is periodically set according to the vehicle state In accordance with a comparison result between a current target current and an average value of past target currents (for example, steps S202 and S206 in the embodiments described later) A standard current control mode for controlling the clutch and a holding current control mode for energizing the motor with a low current capable of maintaining the clutch in a connected state. While step (e.g., step S204 in the embodiment) for switching the motor control on whether, characterized in that it comprises, as.

  According to a sixth aspect of the present invention, in the method for controlling a seat belt device for a vehicle according to the fifth aspect of the present invention, the holding current control mode is a state before energization at a substantially minimum value capable of maintaining the clutch in a connected state. And a step of energizing with an intermediate current value larger than the minimum value (for example, steps S207 and S208 in the embodiments described later).

  According to a seventh aspect of the present invention, in the method for controlling a seat belt device for a vehicle according to the fifth or sixth aspect, when the current control is shifted from the holding current control mode to the standard current control mode, the current per time A step (for example, S210 in an embodiment described later) for limiting the increase amount to a regulation value or less is provided.

According to the first and fifth aspects of the invention, the target current is periodically set according to the vehicle state, and the standard current control mode is set according to the comparison result between the current target current and the average value of the past target current. Since the motor control is switched to one of the holding current control mode and the belt reel winding position change is large, it is predicted that the webbing winding stage will occur. In a situation where the belt reel winding position change is small and it is predicted that it is an occupant restraint stage by webbing, the occupant can be restrained without giving a sense of pressure to the occupant by holding current control.

  According to the second and sixth aspects of the present invention, in the holding current control mode, before energizing at a substantially minimum value that can maintain the clutch in the engaged state, energization is performed at an intermediate current value larger than the minimum value. Therefore, even when the restraint is intermittently executed in a state where the target current is relatively small, it is possible to prevent the webbing from being pulled out due to a change in the vehicle state immediately after the current is reduced.

According to the third and seventh aspects of the invention, when the holding current control mode is shifted to the standard current control mode , the current increase amount per hour is limited to a regulation value or less, and the webbing tension increases rapidly. Therefore, it is possible to reduce the sudden feeling of operation and improve the comfort.

According to the fourth aspect of the present invention, since the regulation value of the current increase speed when the holding current control mode is shifted to the standard current control mode is set so as to increase as the vehicle speed increases , the vehicle speed When the speed is high, the regulation value (allowable width) of the current increasing speed can be increased to give priority to the speed of winding the webbing.

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. The retractor 4 is provided with a winding spring (not shown) that urges the belt reel 12 in the webbing winding direction, and the belt reel 12 and the motor 10 are separated by a clutch 20 (see FIGS. 3 and 4) described later. In this state, the tension by the winding spring acts on the webbing 5.

Further, the retractor 4 is provided with a rotation sensor 11 (rotation state detecting means) for detecting the rotation 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.

Further, the retractor 4 is provided with a known emergency lock mechanism 40 that mechanically locks the rotation of the belt reel 12 (drawing of the webbing 5) when a deceleration greater than a set value acts on the vehicle. The emergency lock mechanism 40 locks the rotation of the belt reel 12 in response to a sensing element (not shown) that operates when an acceleration greater than a set value (for example, 2G) is input to the vehicle, and the operation of the sensing element. and a locking king elements (not shown), locking King elements, as the belt reel 12 after the locking operation can unlock the belt reel 12 by being operated to rotate more than the amount set in the webbing winding direction It has become.

  As shown in FIGS. 3 and 4, the power transmission mechanism 13 includes a sun gear 14 integrally coupled to an external tooth 15 for driving input, and a carrier 17 that supports a plurality of planetary gears 16 on the shaft of the belt reel 12. Are combined. 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 motor drive 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 18 is free to rotate, the planetary gear is used. The ring gear 18 is idled by 16 rotations. The clutch 20 controls on / off the transmission of the motor driving force to the belt reel 12 (carrier 17) by controlling the locking and unlocking of the rotation of the ring gear 18 .

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 includes sensors for detecting the state of the vehicle such as the lateral acceleration sensor 29, the longitudinal acceleration sensor 30, the yaw rate sensor 31, the vehicle speed sensor 32, Sensors such as a buckle switch (not shown) for detecting the connection state of the buckle 9 are connected. The controller 21 is connected to current detection means 33 that detects a current flowing through the motor 10.

  In addition, the controller 21 periodically sets a target current to be supplied to the motor 10 according to the vehicle state (for example, 5 to 20 msec / cycle), and a standard target set by the target current setting unit 34. The standard current control means 35 for controlling the energization current of the motor 10 so as to match the current, the holding current control means 36 for energizing the motor 10 with a low current capable of maintaining the clutch 20 in the connected state, and the target current setting means 34 And a current control selection means 37 for monitoring the change with time of the target current set in step (1) and selecting either the standard current control means 35 or the holding current control means 36 according to the change with time of the target current. The controller 21 controls energization of the motor 10 by the current control means (current control mode) selected by the current control selection means 37.

The target current setting means 34 determines a standard target current required for winding the webbing 5 by calculation, reference of a map, or the like based on detection signals of the lateral acceleration sensor 29 and the yaw rate sensor 31.
The standard current control means 35 always feeds back the actual energization current value of the motor 10 through the current detection means 33, and controls the current so that the energization current of the motor 10 matches the standard target current.
The holding current control means 36 finally energizes the motor 10 with a minimum current (for example, 0.2 A) that can maintain the clutch 20 in the engaged state. An intermediate current value (for example, 0.6 A) larger than the minimum value is energized for a predetermined time (for example, 01 sec). In the case of this embodiment, the holding current control means 36 also performs current control so as to match the target current (intermediate current value or minimum value) by feedback control.
The current control selection unit 37 stores, for example, the standard target current Id periodically set by the target current setting unit 34 as data, obtains the average current value Iavg from the data of the standard target current Id, and obtains the current standard. The target current Id is compared with the average current value Iavg. Then, for example, when Id * 0.8 ≧ Iavg, current control by the standard current control means 35 is selected, and when Id * 0.8 <Iavg, current control by the holding current control means 36 is selected.
The average current value Iavg used in the current control selection means 37 is calculated not only when the webbing 5 is wound by the motor 10 but also in other situations (normal state), as shown in FIG. In a situation where the winding by the motor 10 is not performed (normal state), the calculation of the average current value Iavg is reset when the drawing position of the webbing 5 is equal to or higher than a preset upper limit value or lower limit value. This eliminates the problem that the average current value Iavg changes unnecessarily greatly during normal times.

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 a main flow by the controller 21.
In step S1 of the main flow, it is determined whether or not the vehicle is currently traveling based on the detection value of the vehicle speed sensor 32, etc., and if YES, the process proceeds to step S2, and if NO, Proceed to step S5.
In step S2, sensor information such as the acceleration sensors 29 and 30 and the yaw rate sensor 31 is read. In the next step S3, it is determined whether or not passenger restraint by the webbing 5 is currently required based on the sensor information. Whether or not occupant restraint is required in step S3 is determined based on, for example, whether acceleration or yaw rate deviation exceeds a reference value. However, the determination of whether or not occupant restraint is necessary is not limited to this. Whether the wheel slip angle exceeds the set value, whether the absolute value of the difference between the left and right wheel speeds exceeds the set value, and the behavior You may make it carry out by the presence or absence of the action | operation of a stabilizer (VSA, ABS, TCS, etc.).
If YES in step S3, the process proceeds to constraint control process S4. After the constraint control process S4 is completed, the process proceeds to step S5. If NO, the process proceeds to step S5.
In step S5, it is determined whether or not the drawing position of the webbing 5 is within a preset upper and lower limit value range. If YES, the process returns. If NO, the process proceeds to step S6 and the average current is determined. It returns after resetting the calculation of the value Iavg.

FIG. 7 shows a flow of the constraint control process S4.
In the constraint control process S4, first, a target current Itarget update process (setting process) S101 is performed, and then the motor 10 is energized in step S102. Note that the first energization in step S102 is executed with a preset initial current I0.

In the next step S103, it is determined whether or not the current energizing current I of the motor 10 matches the target current Itarget. If YES, the process proceeds to step S104. If NO, the process proceeds to step S109. move on.
In step S104, it is determined whether or not the current conducting current I is smaller than the target current Itarget. If YES, the process proceeds to step S105, and if NO, the process proceeds to step S106.
In step S105, it is determined whether or not the preset upper limit value Iupper_limit is not reached when the minute current ΔI is added to the current energizing current I. If YES, the minute current Δ is added in step S107. The process proceeds to step S109 later, and in the case of NO, the process proceeds to step S109 as it is.
On the other hand, in step S106, it is determined whether or not the preset lower limit Ilower_limit is exceeded when the minute current ΔI is subtracted from the current energizing current I. If YES, the minute current ΔI is subtracted in step S108. After that, the process proceeds to step S109, and in the case of NO, the process proceeds to step S109 as it is.
Steps S103 to S107 and S108 described here compare the current energization current with the target current, and if both are equal, the energization is continued as it is, and the current energization current is larger or smaller than the target current. In this case, the energization current is increased or decreased within a range not exceeding the upper and lower limit values.
In step S109, it is determined whether the constraint release condition is satisfied, for example, whether the acceleration and the yaw rate deviation are below a reference value. At this time, in the case of YES, the constraint control process is terminated, and in the case of NO, the process returns to the update process S101 of the target current Itarget.

FIG. 8 shows a flow of the update process S101 of the target current Itarget.
In step S201 of the target current Itarget update process S101, the detection signals of the lateral acceleration sensor 29 and the yaw rate sensor 31 are read, and the previous target current Itarget value is substituted into Iold.
In the next step S202, the standard target current Id is obtained by calculation or map reference based on the lateral acceleration Gy and the yaw rate deviation δγ, and in step S203, the average is calculated based on the data of the standard target current Id and the number of samplings n. The current value Iavg is calculated.

  In the next step S204, it is determined whether or not the current standard target current Id is smaller than the average current value Iavg to some extent, for example, whether Id * 0.8 is lower than the average current value Iavg, and YES If NO, the process proceeds to step S205. If NO, the process proceeds to step S206.

  In step S206, the reduction control flag serving as a determination index for shifting to the holding current control mode (control by the holding current control means 36) is turned OFF, the current standard target current Id is substituted for the target current Itarget, and the next step S209 is executed. Proceed to After step S206, the standard current control mode (control by the standard current control means 35) is executed.

  In step S205, it is determined whether the reduction control flag is currently ON. If YES, the process proceeds to step S207. If NO, the process proceeds to step S208. That is, if YES is determined in step S204 for the first time and the reduction control flag is OFF, the process proceeds to step S208. If YES is determined in the second time or later in step S204, the process proceeds to step S207.

  In step S207, a reduced current Ired (t) that can maintain the clutch 20 in the engaged state is substituted for the target current Itarget. This reduced current Ired (t) changes according to the elapsed time t from the change point of the control mode, and as shown in FIG. 10, until the elapsed time t reaches a set time (for example, 1 sec), it is intermediate. The current value (for example, 0.6 A) is set, and after the set time has elapsed, the minimum value (for example, 0.2 A) that can maintain the clutch 20 in the engaged state is set. After step S207, the process proceeds to step S209.

In step S208, the timer value for measuring the time t used in the calculation of the reduced current Ired (t) is set to 0, the reduction control flag is turned ON, and the target current Itarget is reduced to the reduced current Ired (t ). At this time, since t is 0, the target current Itarget is set to an intermediate current value (for example, 0.6 A). After step S208, the process proceeds to step S209.
In addition, when passing through step S207 and step S208, a holding current control mode (control by the holding current control means 36) is performed.

  In step S209, it is determined whether or not the difference between the current target current Itarget and the previous target current Iold exceeds the regulation value ΔI (v). If YES, the process proceeds to step S210, and if NO, processing is performed. Exit. The regulation value ΔI (v) changes according to the current vehicle speed v, and is set to a constant value C2 until it reaches a set vehicle speed (for example, 40 km / h) as shown in FIG. Later, it is set to increase in accordance with C1 · v + C2, that is, the vehicle speed. Note that the regulation value ΔI may be set not only by the vehicle speed but also by taking into account the vehicle momentum such as the yaw rate deviation.

  In step S210, the value obtained by adding the regulation value ΔI (v) to the previous target current Iold is reset as the current target current Itarget. That is, the current target current Itarget is corrected so that the amount of current increase from the previous target current Iold is limited to the regulation value ΔI (v). After step S210, the process ends.

FIG. 12 is a timing chart showing an example of control by the controller 21 of the seat belt device 1.
Hereinafter, this timing chart will be described.
When the vehicle travels with the seat belt device 1 attached, the standard target current Id is always calculated based on the lateral acceleration and yaw rate deviation of the vehicle, and the result is a comparison value obtained by multiplying the result by, for example, 0.8 (in FIG. 12). (See dotted line). In parallel with this, sampling of the standard target current Id and calculation of the average current value Iavg are performed.

In the case of this timing chart, the energization current of the motor 10 is first controlled to reach the standard target current Id, and energization is performed with the standard target current Id as the target current for a while. When energization with the standard target current Id is continued in this way, the comparison value (Id * 0.8) falls below the average current value Iavg (see “Switch 1” in FIG. 12), and at this point, the target current is reduced. Switch to I red (t). The reduced current I red (t) is set to, for example, the minimum value 02A that can maintain the clutch 20 in the engaged state after being set to the intermediate current value 0.6A for 1 second.

Then, after energization with the reduced current I red (t) is continued in this way, when the comparison value (Id * 0.8) exceeds the average current value Iavg (see “Switch 2” in FIG. 12), The target current is switched again to the standard target current Id. At this time, when the target current is switched to the standard target current Id and the standard target current Id increases, the maximum increase rate of the target current is limited to a specified value ΔI (v) or less.

In this way, energization with the standard target current Id is continued, and when the comparison value (Id * 0.8) falls below the average current value Iavg again (see “Switch 3” in FIG. 12), the target current decreases at this time. Switch to I red (t).

As described above, in the seat belt device 1, the target current is periodically set according to the state of the vehicle, and the standard current control mode is set according to the comparison result between the current target current and the past average current value. Since the current control is switched to either the energization with the standard target current Id or the holding current control mode (the energization with the reduced current Ired (t)), the winding position change of the belt reel 12 is large and the webbing 5 is wound. In a situation where the take-up stage is predicted, the webbing 5 is quickly taken up by the standard current control mode, and the change in the take-up position of the belt reel 12 is small, and it is predicted that the webbing 5 is in the passenger restraint stage. Then, restraint can be performed without giving a sense of pressure to the occupant by the holding current control mode.
In the holding current control mode, since the clutch 20 can be maintained in the connected state, the motor 10 and the belt reel 12 are connected via the power transmission mechanism 13 (deceleration mechanism). For this reason, when a pulling direction rotational force acts on the belt reel 12 in the holding current control mode, the torque of the motor 10 in the winding direction corresponding to the driving current is a large regulating force that suppresses the pulling out of the webbing 5. Become.

  Further, in this seat belt device 1, after the transition from the standard current control mode to the holding current control mode, the energization at the intermediate current value is performed for a predetermined time before the energization at the minimum value is performed. Even when the restraint is intermittently executed in a relatively small state, it is possible to prevent the webbing 5 from being pulled out due to a change in the vehicle state immediately after the current decreases.

  Further, in the seat belt device 1, when the holding current control mode is shifted to the standard current control mode, the current increasing speed (current increasing amount per hour) is limited to the regulation value ΔI (v) or less, and the webbing is performed. Since the sudden increase in the tension of 5 can be suppressed, it is possible to eliminate the sudden feeling of operation and to reduce the uncomfortable feeling given to the occupant.

  Further, in this embodiment, since the regulation value ΔI (v) of the current increase speed when the holding current control mode is shifted to the standard current control mode is set so as to increase as the vehicle speed increases, the vehicle speed Therefore, it is possible to appropriately cope with a situation in which the webbing 5 is required to be wound quickly 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 part 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. The figure explaining the reset timing of the average electric current value of the embodiment. The figure explaining holding current control of the embodiment. The figure which shows the change of the regulation value of the electric current increase speed according to the vehicle speed of the embodiment. The timing chart which shows the control of the same embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus 5 ... Webbing 10 ... Motor 12 ... Belt reel 20 ... Clutch 29 ... Lateral acceleration sensor (vehicle state detection apparatus)
31 ... Yaw rate sensor (vehicle state detection device)
34 ... Target current setting means 35 ... Standard current control means 36 ... Holding current control means 37 ... Current control selection means

Claims (7)

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;
In a vehicle seat belt device comprising:
A vehicle state detection device for detecting the state of the vehicle;
Target current setting means for periodically setting a target current to be supplied to the motor based on a detection signal of the vehicle state detection device;
Standard current control means for controlling the energization current of the motor to match the target current set by the target current setting means;
Holding current control means for energizing the motor with a low current capable of maintaining the clutch in a connected state;
In accordance with the comparison result between the current target current set by the target current setting means and the average current value of past target currents set by the target current setting means , the energization and holding current by the standard current control means a current control selecting means for selecting either of the energization of the control means,
A vehicle seat belt device comprising:   2. The holding current control unit performs energization with an intermediate current value larger than the minimum value before energization with a substantially minimum value capable of maintaining the clutch in a connected state. Vehicle seat belt device.   3. The vehicle seat belt device according to claim 1, wherein when current control shifts from the holding current control unit to the standard current control unit, the amount of current increase per hour is limited to a regulation value or less. The regulating value, the seat belt apparatus for a vehicle according to claim 3, characterized in that it is set to be larger with increase in the vehicle speed. 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;
In a method for controlling a seat belt device for a vehicle provided with
Periodically setting a target current to be supplied to the motor according to a vehicle state ;
In accordance with the comparison result between the current target current and the average value of the past target current, a standard current control mode for controlling the energization current of the motor so as to coincide with the target current, and maintaining the clutch in a connected state. Switching the motor control to one of the holding current control modes for energizing the motor with a low current obtained;
A control method for a seat belt device for a vehicle, comprising:   The holding current control mode includes a step of energizing at an intermediate current value larger than the minimum value before energizing at a substantially minimum value capable of maintaining the clutch in a connected state. Item 6. A control method for a vehicle seat belt device according to Item 5.   7. The method according to claim 5, further comprising a step of limiting a current increase amount per time to a regulation value or less when current control is shifted from the holding current control mode to the standard current control mode. 8. A control method for a seat belt device of a vehicle.

Images