JP2010076661A - Seat belt device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device for a vehicle capable of attaining reduction of sense of incongruity given to an occupant by suppressing the operation of an emergency lock mechanism as much as possible. <P>SOLUTION: The seat belt device for the vehicle includes an acceleration sensor 16 for detecting acceleration applied to the vehicle, and a rotation sensor 15 for detecting rotation of a belt reel 12. A controller 18 is provided with: a restriction control means 23 for controlling an energization amount relative to a motor 10 so as to generate an occupant restriction torque; and a rolling-up increase means 30 for returning drawing out of a webbing 5 by the belt reel 12 by increasing the energization amount of the motor, when the acceleration sensor 16 detects acceleration of a set value or higher during motor control by the restriction control means 23 and the rotation sensor 15 detects rotation in a webbing drawing direction of the belt reel 12 under the condition. <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.

  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. Many of the seat belt devices are equipped with an emergency lock mechanism that mechanically locks the webbing drawer in an emergency, and the emergency lock mechanism locks the webbing drawer when a deceleration exceeding a set value acts on the vehicle. In this way, the occupant is restrained to the seat.

In recent years, seatbelt devices have been developed that determine the possibility of collision based on signals from emergency state detection means such as radar and acceleration sensors, and control webbing pull-in when there is a possibility of collision. (For example, refer to Patent Document 1).
The seat belt device includes a motor for retracting the webbing and a control device for controlling the motor, and the control device determines that there is a possibility of a collision based on an input signal from the emergency state detection means. In addition, the webbing is pulled in by the motor, and when the possibility of a collision is avoided, the webbing is released. In addition, in this seat belt device, when a sudden unstable behavior occurs in the vehicle, such as a deceleration greater than a set value acting on the vehicle, a mechanical emergency lock mechanism is activated separately from the webbing pull-in control by the motor. . For this reason, when danger is avoided after the emergency lock mechanism is activated, the motor is driven again after the webbing pull-in control is finished, and the webbing is re-drawn to a position where the lock of the emergency lock mechanism can be released.
JP 2007-326537 A

  However, in this conventional seat belt device, when releasing the webbing in a situation where the emergency lock mechanism is activated, the motor that has once completed the pull-in control is driven again to release the emergency lock mechanism. For this reason, there is a concern that a great tension is applied again to the webbing whose tension has once decreased due to the release of the pull-in control, and the occupant feels uncomfortable by re-driving the motor.

  Therefore, the present invention is intended to provide a vehicle seat belt device capable of reducing the uncomfortable feeling given to the occupant by suppressing the operation of the emergency lock mechanism as much as possible.

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 to be described later), and the belt reel pulls out the webbing after acceleration of a set value or more acts in an arbitrary direction on the vehicle. When the belt reel rotates a predetermined amount or more in the direction, the rotation of the belt reel in the webbing pull-out direction is mechanically locked, and the lock is released by the rotation beyond the set amount in the webbing take-up direction from the belt reel lock position. An emergency lock mechanism (for example, an emergency lock mechanism 19 in an embodiment described later) and the motor In a vehicle seat belt apparatus including a control device that controls the amount of current (for example, a controller 18 in an embodiment described later), an acceleration detection means that detects acceleration acting on the vehicle (for example, in an embodiment described later) An acceleration sensor 16) and rotation detection means (for example, a rotation sensor 16 in an embodiment to be described later) for detecting the rotation of the belt reel, and the control device detects the occupant when a constraint start condition is satisfied. A restraint control means (for example, a restraint control means 23 in an embodiment described later) for controlling the energization amount of the motor so as to generate restraint torque, and the acceleration detection means during the motor control by the restraint control means sets the setting. Acceleration greater than the value is detected, and under that condition, the rotation detecting means Winding increase means (for example, winding increase means 30 in an embodiment to be described later) that increases the amount of current applied to the motor and returns the webbing drawer by the belt reel when rotation is detected. It is characterized by.
As a result, for example, when a predetermined restraint start condition such as the deceleration acting on the vehicle becomes equal to or greater than a set value is satisfied, the restraint control means causes the motor to loosen the webbing and restrain the occupant with the webbing. The amount of current applied to the is controlled. During this time, if the acceleration detecting means detects an acceleration equal to or higher than the set value, and the rotation detecting means detects rotation of the belt reel in the webbing pull-out direction under that condition, the winding increasing means increases the amount of current applied to the webbing. The drawer will come back. This tends to avoid rotation of the belt reel more than a predetermined amount in the webbing pull-out direction.

According to a second aspect of the present invention, in the vehicle seat belt device according to the first aspect, the control means detects the acceleration greater than the set value during the motor control by the constraint control means. In addition, when the rotation detecting unit detects rotation of the belt reel in the webbing pull-out direction over the predetermined amount under the conditions, energization of the motor is performed when the constraint release condition is satisfied thereafter. A lock release control means (for example, the belt reel is rotated more than the set amount in the webbing take-up direction by adding a current amount to the final motor energization amount by the restraint control means or the winding increase means without stopping. Further, it is characterized in that it is provided with a lock release control means 24) in an embodiment described later.
When the restraint control means controls the energization amount to the motor, the acceleration detection means detects an acceleration greater than the set value, and the rotation detection means detects rotation of the belt reel more than a predetermined amount under the conditions ( If it is estimated that the emergency lock mechanism locks the rotation of the belt reel), then, for example, a preset constraint release condition such that the deceleration acting on the vehicle falls below a set value is satisfied. When this is done, the lock release control means adds the current amount to the final motor energization amount by the restraint control means or the winding increase means without stopping energization of the motor, and drives the motor. As a result, the belt reel rotates in the webbing take-up direction, and the belt reel is unlocked by the emergency lock mechanism when the belt reel rotates more than the set amount.

According to a third aspect of the present invention, in the vehicle seat belt device according to the second aspect, the lock release control means is configured to wind the belt reel in accordance with a maximum webbing tension when controlled by the restraint control means. A speed is set, and the belt reel is rotated in the webbing take-up direction at a substantially constant speed set there.
When the emergency lock mechanism is activated during the control by the restraint control means, the maximum tension of the webbing at this time continues to be substantially maintained. In the unlocking control means, the belt reel winding speed is set according to the maximum webbing tension at the time of locking. When the maximum webbing tension is large, the belt reel is wound at a relatively slow and substantially constant speed. It becomes possible to rotate in the direction.

  According to the first aspect of the present invention, during the motor control by the constraint control means, the acceleration detection means detects an acceleration equal to or higher than the set value, and under the conditions, the rotation detection means detects the belt reel in the webbing pull-out direction. When the rotation is detected, the winding increasing means increases the motor energization amount and returns the webbing drawer, so that the operation of the emergency lock mechanism can be suppressed. Therefore, it is possible to reduce the frequency of giving the passenger an uncomfortable feeling associated with the release of the emergency lock mechanism.

  According to the second aspect of the present invention, when the operation of the emergency lock mechanism is detected by the acceleration detection means and the rotation detection means during the motor control by the restriction control means, and the restriction release condition is satisfied after that, the lock is detected. The emergency lock mechanism operates because the release control means adds the current amount to the final motor energization amount in the restraint control means or the winding increase means without rotating the motor energization and rotates the motor in the unlocking direction. Even in such a situation, the belt reel can be unlocked by the motor without causing a large change in tension of the webbing. Therefore, according to the present invention, it is possible to prevent the passenger from feeling uncomfortable when the webbing is unlocked.

  According to the third aspect of the invention, the winding speed of the belt reel at the time of unlocking is set according to the maximum webbing tension at the time of locking, and the belt reel is wound at the winding speed at the winding speed at the time of unlocking. Since the webbing can be rotated in the direction, rapid pull-in in a state where the webbing tension is large can be eliminated, and the uncomfortable feeling given to the passenger can be further reduced.

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 an initial state, and the chest 3 and the abdomen of the occupant 3 are mainly restrained with respect to the seat 2 by the occupant 3 being pulled out by hand and fixing the tongue plate 8 to the buckle 9. To do. In the case of the seat belt device 1, the webbing 5 is pulled in by an electric motor 10 in an emergency, and this motor 10 constitutes a pretension mechanism.

  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 a rotary shaft 10a of the motor 10 via a power transmission mechanism 13 including a clutch (not shown) for power connection / disconnection operation. Further, the retractor 4 is provided with a take-up spring 14 for urging the belt reel 12 in the webbing take-up direction. When the belt reel 12 and the motor 10 are separated by the clutch off operation, the retractor 4 Tension acts on the webbing 5. The clutch in the power transmission mechanism 13 is switched between an on state and an off state triggered by the rotation of the motor 10 in the forward rotation direction (webbing take-up direction) and the reverse rotation direction (webbing pull-out direction). It has become.

Further, the retractor 4 is provided with a rotation sensor 15 (rotation detection means) for detecting the rotation of the belt reel 12. The rotation sensor 15 includes, for example, a magnetic disk in which different magnetic poles are alternately magnetized along the circumferential direction, a pair of Hall elements disposed in proximity to the outer peripheral edge of the magnetic disk, and a Hall element It comprises a sensor circuit for processing the detection signal, and a pulse signal processed by the sensor circuit is output to the controller 18 (control device).
In this case, the pulse signal input from the sensor circuit to the controller 18 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, the controller 18 detects the rotation amount of the belt reel 12 (the amount of webbing 5 pulled out) by counting the pulse signals, and calculates the rotation speed (frequency) of the pulse signal by calculating the change speed (frequency) of the pulse signal. The (drawing speed of the webbing 5) 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 19 that mechanically locks the rotation of the belt reel 12 (drawing of the webbing 5) in an emergency. The emergency lock mechanism 19 includes a sensing element (not shown) that operates when acceleration equal to or greater than a set value is input to the vehicle, and a webbing 5 that rotates a predetermined amount or more in the pull-out direction after the sensing element is activated. A locking element (not shown) for locking the rotation of the belt reel 12 in the pull-out direction is provided. The locking element can unlock the belt reel 12 when the belt reel 12 is rotated by a set amount or more in the webbing take-up direction after the locking operation.

  By the way, in addition to the rotation sensor 15 described above, the controller 18 includes an acceleration sensor 16 (acceleration detecting means) that detects acceleration (deceleration) acting on the vehicle, a buckle switch (not shown) that detects the connection state of the buckle 9, and the like. Many sensors are connected. In this embodiment, the acceleration sensor 16 functions as an emergency state detection unit that detects an emergency state that requires the webbing 5 to be wound, but the emergency state detection unit is configured to detect a detection signal of a front state detection device such as a radar, Alternatively, an operation signal of a brake assist device or the like may be used. The controller 18 is connected to current detection means 17 that detects a current flowing through the motor 10.

  In addition, the controller 18 does not require a restraint condition that requires winding of the webbing 5 or winding of the webbing 5 based on the detected value of the motor control unit 20 that controls the energization current of the motor 10 and the acceleration sensor 16. And a restraint / release condition determination means 21 for determining whether or not the constraint release condition is satisfied.

  For example, the restraint / release condition determination means 21 determines that the restraint condition is satisfied when the absolute value of the vehicle acceleration exceeds the set value G1, and the absolute value of the vehicle acceleration becomes equal to or less than the set value G1 for a predetermined time. Or after the absolute value of the vehicle acceleration becomes equal to or greater than G1, it is determined that the constraint release condition is satisfied when the belt reel 12 changes from the drawn-out state to the winding-up state. The controller 18 determines that the emergency lock mechanism 19 is likely to be activated when the absolute value of the vehicle acceleration exceeds the set value G2 and the belt reel 12 rotates in the pull-out direction, for example. When the absolute value of the acceleration is equal to or less than the set value G2, it is determined that there is no possibility that the emergency lock mechanism 19 is activated.

  The motor control unit 20 includes a constraint control unit 23 that controls a motor energization amount so as to generate torque for occupant restraint when a constraint start condition is satisfied, and an acceleration sensor during motor control by the constraint control unit 23. 16 detects acceleration with an absolute value greater than or equal to G2, and when the rotation sensor 15 detects rotation of the belt reel 12 in the webbing withdrawal direction, the motor energization amount is added and the webbing 5 is withdrawn. The winding reel increasing means 30 for rotating the belt reel 12 in the webbing winding direction, and the acceleration sensor 16 detects an acceleration having an absolute value of G2 or more, and the rotation sensor 15 in the webbing pull-out direction in that situation. When the rotation of the belt reel 12 exceeding a predetermined amount is detected (when the locking operation of the emergency lock mechanism 19 is predicted), it is restrained thereafter. When the removal condition is satisfied, the energizing amount is further added to the final motor energizing amount by the restraint control means 23 or the winding increasing means 30, and the belt reel 12 is rotated in the winding direction to a position where the lock can be released. Unlock control means 24.

  The restraint control means 23 has two types of energization modes: a winding mode 25 and a pull-out suppression mode 26. The winding mode 25 is a mode for quickly removing slack of the webbing 5 and immediately obtaining an occupant restraining force by the webbing 5 at the beginning of the restraint control. Further, the pull-out suppression mode 26 is a mode executed after the slack of the webbing 5 is removed in the winding mode 25, and a low current that can maintain the clutch of the power transmission means 13 in the connected state is supplied to the motor. In this mode, when the webbing 5 is pulled out due to the displacement of the occupant or the like, the energization amount is increased so as to suppress the pulling out.

  When the absolute value of the acceleration acting on the vehicle is equal to or greater than G2, and the possibility that the emergency lock mechanism 19 is activated from this state and the emergency lock mechanism 19 is activated is increased. In order to suppress this operation, the webbing 5 is rewound by the driving force of the motor 10 before the pull-out amount of the belt reel 12 reaches the set amount. For this reason, the energization amount to the motor 10 is increased.

  When the emergency lock mechanism 19 is locked (when it is predicted to be locked), the lock release control means 24 starts from the locked position of the belt reel 12 by the emergency lock mechanism 19 (maximum winding position Xmax of the belt reel 12). The belt reel 12 is rotated in the webbing take-up direction by a set amount or more to a position where the lock of the emergency lock mechanism 19 can be unlocked. During this period, control is performed so that the speed is substantially constant. At this time, for the control of the rotational speed of the belt reel 12, two kinds of control modes of the low speed mode 27 and the high speed mode 28 are selected according to the tension of the webbing 5. In the case of this embodiment, the tension of the webbing 5 is determined based on the maximum current amount Imax during motor control by the restraint control means 23.

Hereinafter, the control by the controller 18 of the seat belt apparatus 1 will be described with reference to the flowcharts of FIGS.
FIG. 3 shows a main flow of processing by the controller 18.
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 X0 is set using the average value of the measured values.
In step S2, the sensor information of the acceleration sensor 16 is read. In step S3, whether or not occupant restraint by the webbing 5 is currently required based on the sensor information, for example, the absolute value of the vehicle acceleration is the set value G1. Judge by whether or not it exceeds.
If YES in step S3, the process proceeds to the constraint control process S100. After the constraint control process S100 is completed, the process proceeds to step S4. In the case of NO, the process proceeds to step S4. In step 4, it is determined whether or not the vehicle is stopped. If it is not stopped, the process returns to step S1, and if it is stopped, the process is terminated.

FIG. 4 shows a flow of the constraint control process S100.
In step S101 of the constraint control process S100, the target winding position X1 of the belt reel 12 is set, and energization of the motor 10 is started with the initial current amount I0.
The target winding position X1 of the belt reel 12 is, for example, a value obtained by adding a set value in the range of 50 mm to 100 mm to the winding reference position X0, and the initial current amount I0 is a value set in advance according to the vehicle acceleration or the like. Use.

In step S102, the current position X of the belt reel 12 is detected, and in the next step S103, it is determined whether or not the current position X is equal to or greater than the target winding position X1.
In the case of YES in step S103, the process proceeds to step S104, the current energization is continued, and the process proceeds to the next step S109. If NO in step S103, the process proceeds to step S105, and it is determined whether or not the difference between the target winding position X1 and the current position X is greater than a specified value Xth. In step 104, when the energization amount for the motor 10 is lower than a predetermined energization amount I1 described later, the energization amount for the motor 10 is increased to I1.
If YES in step S105, the process proceeds to step S106, the energization amount is increased by a minute amount ΔI, and the process proceeds to the next step S109. If NO in step S105, the process proceeds to step S107 to determine whether a predetermined time has elapsed. Note that the minute amount ΔI that increases in step S106 can be set dynamically or statically based on the measured acceleration or other motion state amount obtained by other sensors, or the difference between the winding amount and the target amount. it can.
In the case of YES at step S107, the process proceeds to step S108, the energization amount for the motor 10 is changed to I1, and the process proceeds to the next step S109. The energization amount I1 changed in step S108 is a low current that can maintain the clutch of the power transmission means 13 in the engaged state. Therefore, the energization of the motor 10 shifts to the pull-out suppression mode 26 at this time, and the level of the energization amount to the motor 10 is suppressed low from this time.
If NO in step S107, the process proceeds to the next step S109 as it is.

  In step S109, it is determined whether or not the current absolute value of the vehicle acceleration exceeds the set value G2. If YES, the process proceeds to step S110, and the position of the belt reel 12 when the set value G2 is first exceeded. After storing X as the reference position Xst, the process proceeds to step S111. In step S111, it is determined whether or not the belt reel 12 has been rotated in the webbing pull-out direction. In the case of YES in step S111, the process proceeds to step S112 to validate the lock possibility determination, and further, in step S113, the amount of change of the belt reel 12 (difference between the reference position Xst and the current position X) is calculated. Proceed to S114. If NO in step S109 and NO in step S111, the process proceeds directly to step S114.

  In step S114, the current current amount I is stored, and if the current current amount I is the maximum so far, the maximum current amount Imax is updated and stored, and the current position X of the belt reel 12 is further stored. In the case of the maximum so far, the maximum winding position Xmax is updated and stored.

In the next step S115, it is determined whether or not the occupant has rebounded (return of the occupant in the seat pressing direction after impact input). In this step S115, for example, it is determined that there is rebound when the absolute value of acceleration is greater than G3 and the belt reel 12 rotates in the webbing take-up direction, and it is determined that there is no rebound in other cases.
If YES in step S115, the process proceeds to step S119 after performing the winding increase process S200. If NO, the process proceeds to step S116, and it is checked whether or not there is a possibility of locking in step S112. In the case of YES at step S116, the routine proceeds to step S117, where it is determined whether or not the rotation amount (change amount) ΔX of the belt reel 12 in the pull-out direction is larger than the set value α.
Note that the set value α is a value indicating the minimum rotation amount of the belt reel 12 in the webbing pull-out direction necessary for the emergency lock mechanism 19 to actually lock after the absolute value of the acceleration becomes larger than G2. Therefore, when it is determined NO in step S117, the emergency lock mechanism 19 is not actually operating.
If YES in step S117, the process proceeds to step S118 to enable the lock operation determination and proceeds to step S119. If NO, the winding increasing process S200 is performed and then the process proceeds to step S119.

  Here, the winding increase process S200 is a process of increasing the winding amount of the webbing 5 by the rotation of the motor 10 as will be described later. However, in the case of YES in step S115 (when the occupant rebounds), the winding increase process S200 is immediate. The reason why the process proceeds to the winding increase process S200 is to increase the restraining force without giving the passenger a sense of incongruity by actively pulling in the webbing 5 by using the timing of the tension drop due to the passenger's rebound.

In step S119, it is determined whether or not the unlock condition is satisfied, for example, whether or not the absolute value of the vehicle acceleration is G1 or less. At this time, if YES, the process proceeds to step S120, and if NO, the process returns to step S102.
Therefore, until the unlock condition is satisfied in step S119, the processing from step S102 to step S119 is repeated. At this time, basically, the current position X of the belt reel 12 is allowed from the target winding position X1. The energization amount for the motor 10 is controlled so as to be maintained in the range of the specified value Xth. The control so far substantially corresponds to the function of the constraint control means 23.

In step S120, it is confirmed whether or not the lock operation validity is determined in step S118. If YES, the process proceeds to the lock release process S300, and after the lock release process S300 is completed, the process proceeds to step S121. If NO in step S120, the process proceeds directly to step S121.
In step S121, the motor 10 is reversely rotated for a short time, the clutch in the power transmission mechanism 13 is turned off, and the power transmission is interrupted. Thereafter, the process returns to the main flow.

FIG. 5 shows a flow of the winding increase process S200.
In step S201 of the winding increase process S200, the current energization current to the motor 10 is increased by a minute amount ΔI, and in the next step S202, it is determined whether or not the current position X of the belt reel 12 is equal to or greater than the reference position Xst. . If YES in step S202, the process ends and the process returns to the constraint control process S100. If NO, the process returns to step S201.
Therefore, in the winding increase process S200, the belt reel 12 is rewound by the amount ΔX where the webbing 5 has been pulled out. Accordingly, the pulled-out portion of the webbing 5 is returned by driving the motor 10, the locking operation of the emergency lock mechanism 19 is avoided, and the tension of the webbing 5 is increased by the motor 10.

FIG. 6 shows the flow of the unlocking process S300.
In step S301 of the unlocking process S300, the energization amount I finally stored at the time of constraint control is set as the target energization amount Itarget, and in the next step S302, the maximum current amount Imax stored at the time of constraint control is set as a threshold value. It is determined whether or not the current is greater than I2.
If YES in step S302, the process proceeds to step S303, and the winding target speed Vtarget of the belt reel 12 at the time of unlocking is set to V1, and if NO, the process proceeds to step S304, and at the time of unlocking. The winding target speed Vtarget of the belt reel 12 is set to V2. However, the magnitude relationship between V1 and V2 is V1 <V2. Therefore, when the maximum current amount Imax is equal to or greater than the threshold current I2 and the tension of the webbing 5 in the locked state is large, the winding target speed Vtarget is set to a relatively small fixed value (V1), and the maximum current amount Imax is set to the threshold current I2. When the tension of the webbing 5 in the locked state is smaller than that, the winding target speed Vtarget is set to a relatively large fixed value (V2).

After steps S303 and S304, the process proceeds to step S305 to determine whether or not the current winding speed V of the belt reel 12 is equal to the winding target speed Vtarget. If YES, the process proceeds to step S306, and if NO. In step S307, the process proceeds to step S307.
In step S307, it is determined whether the winding speed V of the belt reel 12 is higher than the winding target speed Vtarget. If YES, the process proceeds to step S308, and the target energization amount Itarget is decreased by a minute amount ΔI. Thereafter, the process proceeds to step S306. If NO in step S307, the process proceeds to step S309.
In step S309, it is determined whether the current energization amount I is increased by a minute amount ΔI or not, and if YES, the process proceeds to step S310, where the target energization amount Itarget is set to the minute amount ΔI. After that, the process proceeds to step S306. If NO in step S309, the process proceeds to step S306 without increasing the target energization amount Itarget.
In step S306, energization is performed with the set target energization amount Itarget.
The processing from step S305 to S306 (including S307 to S310) described here is feedback control for maintaining the winding speed of the motor 10 at a constant speed (Vtarget).

In step S311 subsequent to step S306, is the difference between the current winding position X of the belt reel 12 and the maximum winding position Xmax during restraint control equal to or less than a set value α at which the emergency lock mechanism 19 can be unlocked? Determine if.
If YES in step S311, the process proceeds to step S312. If NO, the process proceeds to step S313.
In step S312, it is determined whether or not the energization amount is equal to or less than the limiter value I3. If YES, the process returns to step S305 and the same unlock control is continued. If NO, the process is terminated. In the case of NO here, since the unlocking by the motor 10 is impossible, the occupant is notified to perform the unlocking manually by a warning display or the like.

In step S313, the passage of a predetermined time is awaited, and in step S314, the motor 10 is energized with a current -I4 in the reverse direction for a minute time (for example, 200 msec). As a result, the motor 10 rotates slightly in the reverse direction, and the clutch in the power transmission mechanism 13 is turned off. In step S315, the process further waits for a predetermined time, and then proceeds to step S316.
In step S316, it is determined again whether or not the difference between the current winding position X of the belt reel 12 and the maximum winding position Xmax at the time of restraint control exceeds a set value α at which the emergency lock mechanism 19 can be unlocked. If YES, the process proceeds to step S312, and if NO, the process is exited. If the determination in step S316 is YES, the belt reel 12 does not return to the webbing pull-out direction for some reason even if the motor 10 is reversely rotated to turn off the clutch. At this time, the emergency lock mechanism 19 The lock has not been released. For this reason, the process for unlocking is executed again by proceeding to step S312.

  As described above, in the seat belt device 1, when the constraint start condition is satisfied by the rapid increase of the acceleration of the vehicle, the current control of the motor 10 by the constraint control unit 23 is started. Due to the relatively large energization amount, the belt reel 5 is quickly wound so that the winding position of the belt reel 12 falls within the specified value Xth from the target winding position X1. As a result, the slack of the webbing 5 is quickly removed, and a tension suitable for restraint is generated in the webbing 5.

  When the winding position of the belt reel 12 is maintained within the specified value Xth from the target winding position X1 for a predetermined time or more, the control mode of the restraint control means 23 shifts to the pull-out suppression mode 26, and the power transmission device 13 Only when there is rotation in the pull-out direction of the belt reel 12 through the webbing 5, the energization amount increases according to the pull-out amount. Is called. Therefore, after the transition to the pull-out suppression mode 26, when the drag by the power transmission mechanism 13 and the motor 10 acts on the webbing 5, the webbing 5 is about to be pulled out by overcoming the drag due to the upper body movement of the occupant. However, the belt reel 12 is rewound. Thereby, the excessive passenger | crew restraint by webbing 5 is eased.

  In this seat belt device 1, during the control by the restraint control means 23, acceleration in an arbitrary direction exceeding G2 acts on the vehicle, and when the webbing 5 is slightly pulled out due to the shake of the upper body of the occupant, The energizing current of the motor 10 is increased so that the winding increasing means 30 returns the webbing 5 withdraw. Thereby, after the acceleration in the arbitrary direction exceeding G2 is detected through the acceleration sensor 16, the belt reel 12 is hardly pulled out to the set value α or more. Therefore, as a result of the locking of the emergency lock mechanism 19 being suppressed, the frequency of releasing the emergency lock mechanism 19 is reduced, and the frequency of giving the passenger a sense of discomfort associated with the release of the emergency lock mechanism 19 is also reduced.

  In the seat belt device 1, the locking operation of the emergency lock mechanism 19 is suppressed by the operation of the winding increasing means 30 as described above. However, in the situation where the webbing 5 is pulled out rapidly, the motor 10 It is conceivable that the emergency lock mechanism 19 is activated due to a delay in the control. In this case, after the vehicle state is stabilized (after the constraint release condition is satisfied), the energization of the motor 10 is not stopped and the final motor energization amount by the restraint control means 23 or the winding increase means 30 is further increased. The amount of current is added, and the control shifts to the lock release control means 24. For this reason, the tension of the webbing 5 is not completely released before the belt reel 12 is rotated in the retracting direction in order to unlock the emergency lock mechanism 19. Accordingly, when the lock is released, a sudden change in the tension of the webbing 5 does not give the passenger an uncomfortable feeling, and the amount of current necessary for the release can be reduced.

Further, in the control by the lock release control means 24, the belt reel 12 is rotated in the winding direction at a substantially constant speed (winding target speed Vtarget), so that the occupant feels uncomfortable due to a sudden change in the drawing speed of the webbing 5. Never give to.
The winding speed of the belt reel 12 at the time of unlocking is set according to the maximum current amount at the time of control by the restraint control means 23, that is, the tension of the webbing 5, so that the tension of the webbing 5 is large and the passenger is compressed greatly. Under circumstances where it is easy to give a feeling, the lock can be released slowly. Therefore, the uncomfortable feeling given to the occupant can be further reduced.

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.
For example, in the case of the above embodiment, in the restraint control process S100 (the step between step S102 and step 109 in FIG. 4), the current position X of the belt reel 12 is changed from the target winding position X1 to the allowable specified value Xth. The energization amount for the motor 10 is controlled so as to be maintained in this range, but the energization current for the motor 10 may be set based on a signal of a sensor that detects a vehicle state such as an acceleration sensor. .

1 is an overall schematic configuration diagram of a seat belt device according to an embodiment of the present invention. The schematic block diagram of the retractor part of the seatbelt apparatus 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 flowchart which shows the flow of control of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sheet-helt apparatus 5 ... Webbing 10 ... Motor 12 ... Belt reel 15 ... Rotation sensor (rotation detection means)
16 ... Acceleration sensor (acceleration detection means)
18 ... Controller (control device)
DESCRIPTION OF SYMBOLS 19 ... Emergency lock mechanism 23 ... Restriction control means 24 ... Lock release control means 30 ... Winding increase means

Claims (3)

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;
When the belt reel rotates a predetermined amount or more in the webbing pull-out direction after an acceleration greater than a set value is applied to the vehicle in an arbitrary direction, the belt reel is mechanically locked to rotate in the webbing pull-out direction, and the belt reel An emergency locking mechanism in which the lock is released by rotation of a set amount or more in the webbing take-up direction from the lock position;
A control device for controlling the amount of current to be supplied to the motor;
In a vehicle seat belt device comprising:
Acceleration detecting means for detecting acceleration acting on the vehicle;
Rotation detection means for detecting the rotation of the belt reel,
The control device includes:
A restraint control means for controlling an energization amount to the motor so as to generate an occupant restraint torque when a restraint start condition is satisfied;
During the motor control by the restraint control means, when the acceleration detection means detects an acceleration equal to or higher than the set value, and the rotation detection means detects rotation of the belt reel in the webbing withdrawal direction under the conditions. A winding increasing means for increasing the motor energization amount and returning the webbing drawer by the belt reel;
A vehicle seat belt device comprising:   The control means detects, during the motor control by the constraint control means, the acceleration detection means detects an acceleration equal to or higher than the set value, and under the conditions, the rotation detection means detects the belt reel in the webbing pull-out direction. When a rotation greater than or equal to a predetermined amount is detected, when the constraint release condition is subsequently satisfied, the energization to the motor is further stopped without stopping the energization to the motor, and the final motor energization amount by the winding control unit is further increased. The vehicle seat belt device according to claim 1, further comprising: a lock release control unit that adds a current amount and rotates the belt reel in the webbing winding direction by the set amount or more.   The unlocking control means sets the winding speed of the belt reel in accordance with the maximum webbing tension at the time of control by the restraining control means, and rotates the belt reel in the webbing winding direction at a substantially constant speed set there. The vehicle seat belt device according to claim 2, wherein

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