JP5538497B2 - Seat belt device - Google Patents

Description

  The present invention relates to a seat belt device.

  Conventionally, for example, the motor is rotated in the winding direction of the belt by current feedback control in an emergency in which the possibility of occurrence of a vehicle collision is high, and when the collision is avoided, the motor is belted by current feedback control with the maximum allowable current. There is known a seat belt device that rotates in a pulling direction of the belt and puts the belt in an unloaded state (for example, see Patent Document 1).

JP 2008-30668 A

  By the way, according to the seat belt device according to the above-described prior art, the winding of the belt is only controlled by the current feedback control with respect to the motor regardless of the possibility of collision. As a result, the desired quietness and comfort cannot be ensured, and there is a risk that the passenger will feel uncomfortable.

For example, when removing the slack of the belt in a state where there is no possibility of collision, the belt is allowed to be wound more gently than when the possibility of collision is high.
In such a case, simply executing the current feedback control is necessary to ensure the desired quietness of the motor rotation speed due to individual differences in the power transmission mechanism between the motor and the belt. May exceed the upper limit of rotation speed.

  Further, for example, if the voltage applied to the motor fluctuates depending on the state of the power supply, etc., the rotational speed of the motor fluctuates without stability, so that the desired quietness cannot be ensured and the belt Winding becomes unstable. For example, it becomes impossible to ensure desired comfort due to insufficient winding of the belt due to a decrease in supply power, or an unnecessarily large tension acting due to an increase in supply power.

  In addition, by always applying a single control (eg, current feedback control) to the motor regardless of the possibility of a collision, the processing capability of the processing device can be reduced. It cannot be efficiently distributed with other processes whose priority is changed according to various situations. Thereby, the problem that the processing load of a processing apparatus cannot be reduced appropriately arises.

  The present invention has been made in view of the above circumstances, and by increasing the flexibility of control while ensuring desired safety, it is possible to reduce processing load and ensure desired silence and comfort. It is an object of the present invention to provide a seat belt device capable of the above.

  In order to solve the above problems and achieve the object, the seat belt device according to the first invention of the present invention is wound with a webbing (for example, webbing 5 in the embodiment) for restraining a vehicle occupant. A belt reel that is rotated (for example, the belt reel 10 in the embodiment), a motor that rotationally drives the belt reel (for example, the motor 13 in the embodiment), and a rotation angle that detects the rotation angle of the motor. Detection means (for example, the rotation angle sensor 32 in the embodiment), current detection means (for example, the current sensor 33 in the embodiment) for detecting a current to be supplied to the motor, and the motor to be supplied with current Collision for determining whether or not the possibility of occurrence of collision between the control means for controlling the current (for example, the motor control unit 42 in the embodiment) and the vehicle and an object outside the vehicle is equal to or greater than a predetermined value. Measuring means (for example, the collision prediction unit 41 in the embodiment), and the control means, when the collision prediction means determines that the possibility of occurrence of the collision is greater than or equal to the predetermined value. Ignoring the detection result of the rotation angle detection means, and executing a first control for causing the current supplied to the motor to follow the target current by current feedback control based on the detection result of the current detection means, and performing the collision prediction The rotation angle of the motor follows the target rotation angle by rotation angle feedback control based on the detection result of the rotation angle detection means, except when it is determined by the means that the possibility of occurrence of the collision is not less than the predetermined value. And based on the detection result of the current detection means, the second control is performed to restrict the current supplied to the motor within a predetermined current range.

  Furthermore, a seat belt device according to a second aspect of the present invention includes a power supply means (for example, the power source 22 in the embodiment) for supplying power to the motor, and a power supply (for example, implementation) of the power supply means. Power detection means (for example, voltage sensor 34 in the embodiment) for detecting the power supply voltage in the form of the power supply voltage, and the control means is configured such that the supply power detected by the power supply means is less than a predetermined power. In this case, the rotation angle feedback control is executed without executing the current feedback control.

  Furthermore, in the seatbelt device according to the third aspect of the present invention, the control unit is configured to control the first control and the second control when the supply power detected by the power supply unit is equal to or greater than the predetermined power. And executing initial control for supplying initial power to the motor prior to execution of the current feedback control and the rotation angle feedback control, and the supply power detected by the power supply means is less than the predetermined power. The initial power in a certain case is set larger than the initial power in the case where the supplied power detected by the power supply means is equal to or greater than the predetermined power.

  Furthermore, a seat belt device according to a fourth aspect of the present invention is interposed between the motor and the belt reel, and the motor and the belt reel are connected in response to rotation in one direction of the motor. And connecting / disconnecting means (for example, clutch 11 in the embodiment) for disconnecting the motor and the belt reel in response to rotation of the motor in the reverse direction, and the control means reverses the motor. When the supply power detected by the power supply means is less than the predetermined power when rotating in the direction, the webbing withdrawal amount is equal to or greater than the predetermined withdrawal amount based on the detection result of the rotation angle detection means. The rotation in the reverse direction is stopped.

According to the seat belt device of the first aspect of the present invention, the rotation state of the motor can be stabilized to a desired constant state by the rotation angle feedback control. Thereby, for example, the desired quietness and comfort can be ensured regardless of individual differences in the power transmission mechanism between the motor and the webbing or fluctuations in the voltage applied to the motor.
Furthermore, by combining the rotation angle feedback control with control for regulating the current supplied to the motor, it is possible to prevent an excessive current from being supplied to the motor even when the rotation angle detection means is abnormal. be able to. In this case, in addition to the execution of the control for driving the motor, the processing capability of the control means can also be allocated to the diagnosis of the presence / absence of abnormality of the rotation angle detection means.

  Further, by ignoring the detection result of the rotation angle detection means when executing the current feedback control, the processing load required for the diagnosis of the rotation angle detection means is reduced while preventing an excessive current from being supplied to the motor. be able to. Thereby, the processing capability of the control means can be allocated to other processes such as monitoring of the presence / absence of a highly urgent event (for example, the presence / absence of an event in which the possibility of a collision is a predetermined value or more).

Therefore, when it is determined that the possibility of the collision is equal to or higher than the predetermined value, the first control is executed, thereby preventing the excessive current from being applied and the possibility of the collision occurrence being the predetermined value. Whether this is the case or not can be monitored at an appropriate frequency and timing.
On the other hand, if the possibility of occurrence of a collision is determined to be greater than or equal to a predetermined value, the second control is executed to ensure the desired quietness and comfort, and whether there is an abnormality in the rotation angle detection means Can be monitored at an appropriate frequency and timing.
Thus, it is possible to perform appropriate motor control according to each monitoring result.

According to the seat belt device of the second aspect of the present invention, even when the supplied power is less than the predetermined power, the webbing can be appropriately controlled, and the desired safety can be obtained without giving the passenger a sense of incongruity. Can be secured.
For example, even if it is difficult to stabilize the rotation state of the motor by current feedback control due to insufficient supply power, the rotation state of the motor can be stabilized to a desired constant state by rotation angle feedback control. it can.
Thereby, for example, the desired quietness and comfort can be ensured regardless of individual differences in the power transmission mechanism between the motor and the webbing or fluctuations in the voltage applied to the motor.

According to the seat belt device of the third aspect of the present invention, the initial power is supplied to the motor 13 prior to the start of the execution of the current feedback control or the rotation angle feedback control. Thus, the webbing can be prevented from starting suddenly. As a result, it is possible to prevent the winding of the webbing from giving an uncomfortable feeling to the occupant.
Further, for example, the current that is supplied to the motor when the voltage output from the power supply means is less than a predetermined voltage, and the current that is supplied to the motor when the voltage output from the power supply means is equal to or higher than the predetermined voltage. By making it larger than this, it is possible to ensure the desired initial power by compensating for the voltage drop by increasing the current.

According to the seat belt device of the fourth aspect of the present invention, even when the supplied power is less than the predetermined power, the motor and the belt reel are connected while preventing the motor from rotating in the reverse direction excessively. Can be switched to the shut-off state accurately.
For example, due to insufficient supply power, it is difficult to stabilize the rotational state of the motor due to individual differences in the power transmission mechanism between the motor and the webbing or fluctuations in the voltage applied to the motor. However, the reverse rotation of the motor can be stopped at an appropriate timing according to the webbing pull-out amount.

It is a lineblock diagram of a seatbelt device concerning an embodiment of the invention. It is a lineblock diagram of a seatbelt device concerning an embodiment of the invention. It is a flowchart which shows operation | movement of the seatbelt apparatus which concerns on embodiment of this invention.

  Hereinafter, a seat belt device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

A seat belt device 1 according to the present embodiment is a so-called three-point seat belt device capable of restraining an occupant 3 seated on a vehicle seat 2 as shown in FIG. 1, for example, and is attached to a center pillar (not shown). The webbing 5 is pulled out from the retractor 4 substantially upward in the vertical direction.
The webbing 5 is inserted through a through anchor 6 supported on the upper side of the center pillar, and the tip of the webbing 5 is fixed to the vehicle body floor via an outer anchor 7 closer to 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 is 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 is possible.

The webbing 5 is wound around the retractor 4 in an initial state (for example, an unmounted state), and is pulled out from the belt reel 10 by the occupant 3, and the tongue plate 8 is mounted and fixed to the buckle 9. The body (for example, chest and waist) is restrained with respect to the seat 2.
In the seat belt device 1, the webbing 5 is wound up by a driving force of a motor 13 that applies a rotational force to the belt reel 10 in an emergency or a change in vehicle behavior.

In the retractor 4, for example, as shown in FIG. 2, a belt reel 10 around which a webbing 5 is wound is rotatably supported by a retractor frame (not shown), and a shaft 10a of the belt reel 10 is externally connected from one end side of the retractor frame. Protrusively toward.
The shaft 10a of the belt reel 10 is connected to a rotating shaft 13a of a motor 13 via a power transmission mechanism 12 having a clutch 11 for power connection / disconnection and a gear mechanism (not shown).

The clutch 11 in the power transmission mechanism 12 can disconnect the connection between the motor 13 and the belt reel 10 according to the rotation state of the motor 13.
The retractor 4 is provided with a take-up spring (not shown) for urging the belt reel 10 in the take-up direction of the webbing 5. When the belt reel 10 and the motor 13 are separated by the clutch 11, the retractor 4 Tension acts on the webbing 5.

The clutch 11 is connected to the power transmission mechanism 12 in response to an input of rotational torque in the forward rotation direction of the motor 13 (winding direction of the webbing 5), and in the reverse rotation direction of the motor 13 (drawing direction of the webbing 5). The power transmission mechanism 12 is shut off in response to the input of rotational torque.
The retractor 4 includes an emergency lock mechanism 14 that mechanically locks the delivery of the webbing 5 when, for example, a deceleration exceeding a predetermined value acts on the vehicle.

  Further, the seat belt device 1 includes, for example, a motor drive unit 21, a power source 22, a control device 23, a buckle switch 31, a rotation angle sensor 32, a current sensor 33, a voltage sensor 34, and a vehicle state sensor 35. And a radar device 36.

The buckle switch 31 outputs, for example, an ON signal when the tongue plate 8 is attached and fixed to the buckle 9, and outputs an OFF signal when the tongue plate 8 is detached from the buckle 9.
For example, the rotation angle sensor 32 outputs a detection signal of the rotation position (that is, the rotation angle) of the belt reel 10.
The current sensor 33 outputs, for example, a detection signal of a current that is supplied to the motor 13.
The voltage sensor 34 outputs, for example, a power supply voltage detection signal output from the power supply 22.
The vehicle state sensor 35 includes, for example, a speed sensor, a yaw rate sensor, an acceleration sensor, a brake switch, and the like, and outputs detection signals relating to various states of the vehicle.
The radar device 36 detects, for example, based on a transmission signal of an electromagnetic wave transmitted toward a detection target region set in the outside of the vehicle and a reflection signal of a reflected wave generated by reflecting the transmission signal by an object. A signal (for example, a detection signal related to the distance from the radar apparatus to the object) is output.

  The motor drive unit 21 includes, for example, a bridge-connected switching element, and controls the energization amount and energization direction of the current energized from the power source 22 to the motor 13 in accordance with a control signal output from the control device 23. .

  The control device 23 configured by an electronic circuit such as a CPU (Central Processing Unit) includes, for example, a collision prediction unit 41 and a motor control unit 42.

  For example, the collision prediction unit 41 determines whether or not the possibility of collision between the vehicle and an object outside the vehicle is equal to or greater than a predetermined value based on signals output from the vehicle state sensor 35 and the radar device 36. . If it is determined that the possibility of a collision is greater than or equal to a predetermined value, a pre-crash request that instructs execution of a predetermined operation required for collision avoidance or impact reduction at the time of collision is output.

  For example, when the distance to an object (such as another vehicle) existing in the vicinity of the vehicle is less than a predetermined distance, the collision prediction unit 41 has a relative approach speed of an object existing in the vicinity of the vehicle equal to or higher than a predetermined speed. The possibility of collision between the vehicle and an object outside the vehicle is greater than or equal to a predetermined value based on each or an appropriate combination, such as when It is determined that

  For example, the motor control unit 42 outputs a control signal for controlling a current supplied to the motor 13.

  For example, when the collision prediction unit 41 determines that the possibility of occurrence of the collision is equal to or greater than a predetermined value, the motor control unit 42 ignores the detection signal of the rotation angle sensor 32 and detects the detection signal of the current sensor 33. The first control for causing the current supplied to the motor 13 to follow the target current by the current feedback control based on the above is executed.

For example, the motor control unit 42 performs the rotation angle feedback control based on the detection signal of the rotation angle sensor 32 except when the collision prediction unit 41 determines that the possibility of occurrence of the collision is a predetermined value or more. Make the rotation angle follow the target rotation angle. Further, based on the detection signal of the current sensor 33, the second control is executed to regulate the current supplied to the motor 13 within a predetermined current range while diagnosing the presence or absence of abnormality of the rotation angle sensor 32.
For example, when a current exceeding a predetermined current range is detected by the current sensor 33, the motor control unit 42 determines that the rotation angle sensor 32 is abnormal and sets the current supplied to the motor 13 to a predetermined current range. Regulate within.

For example, when the power supply voltage detected by the voltage sensor 34 is equal to or higher than a predetermined voltage, the motor control unit 42 performs the first control and the second control.
For example, when the power supply voltage detected by the voltage sensor 34 is less than a predetermined voltage, the motor control unit 42 executes the rotation angle feedback control without executing the current feedback control.

For example, prior to the execution of current feedback control and rotation angle feedback control, the motor control unit 42 executes initial control for supplying initial power to the motor 13 by fixed duty control.
In the fixed duty control, for example, the duty according to the on / off ratio when the switching element of the motor driving unit 21 is turned on / off by pulse width modulation or the like is fixed to a predetermined value, and the constant duty control is performed. This is control for energizing the motor 13.
For example, the motor control unit 42 sets the initial power when the power supply voltage detected by the voltage sensor 34 is lower than a predetermined voltage to be larger than the initial power when the power supply voltage is equal to or higher than the predetermined voltage.

  For example, when the motor control unit 42 rotates the motor 13 in the reverse direction to switch the connection state of the power transmission mechanism 12 by the clutch 11 to the cutoff state, the power supply voltage detected by the voltage sensor 34 is less than a predetermined voltage. In some cases, based on the detection signal of the rotation angle sensor 32, when the pull-out amount of the webbing 5 reaches a predetermined pull-out amount, the rotation of the motor 13 in the reverse direction is stopped.

  The seat belt apparatus 1 according to the present embodiment has the above-described configuration, and the operation of the seat belt apparatus 1 will be described next.

First, for example, in step S01 shown in FIG. 3, it is determined whether or not the power supply voltage is equal to or higher than a predetermined voltage (for example, a lower limit voltage capable of starting the internal combustion engine of the vehicle, such as 8V for a 12V battery). To do.
If this determination is “NO”, the flow proceeds to step S 15 described later.
On the other hand, if this determination is “YES”, the flow proceeds to step S 02.

Next, in step S02, it is determined whether or not an ON signal is output from the buckle switch 31.
If this determination is “YES”, the flow proceeds to step S 04 described later.
On the other hand, if this determination is “NO”, the flow proceeds to step S 03.
In step S03, the storing operation of winding the webbing 5 to the predetermined all storage position is performed by the belt reel 10 while assisting with the driving force of the motor 13, and the process proceeds to the end.

Next, in step S04, as a predetermined initial control prior to the execution of the rotation angle feedback control, the motor 13 is initially set with a first fixed duty (for example, a 20% duty corresponding to a current of 6 A for 10 ms). First fixed DUTY control for supplying electric power is executed.
Next, in step S05, the rotation angle feedback control based on the detection signal of the rotation angle sensor 32 causes the rotation angle of the motor 13 to follow the target rotation angle, and the motor 13 is energized based on the detection signal of the current sensor 33. The second control is performed to restrict the current to be within a predetermined current range.

Next, in step S06, the current (drive current) applied to the motor 13 is a predetermined current (for example, a current that causes the tension acting on the webbing 5 to become a predetermined tension required for removing slack, such as 3A) or more. It is determined whether or not.
If the determination result is “NO”, the determination process of step S06 is repeatedly executed.
On the other hand, when the determination result is “YES”, the execution of the second control is ended, and the process proceeds to Step S07.

  Next, in step S07, as a control for switching the connection state of the power transmission mechanism 12 by the clutch 11 to the cutoff state, a second fixed duty (for example, a 25% duty corresponding to a current of 7.5 A for 100 ms, etc.) ) To execute the second fixed DUTY control (reverse rotation) to reverse the motor 13.

Next, in step S08, the reverse rotation of the motor 13 is stopped.
Next, in step S09, it is determined whether a pre-crash request has been output.
If this determination is “NO”, the flow returns to step S 01 described above.
On the other hand, if the determination is “YES”, the flow proceeds to step S10.

Next, in step S10, as predetermined initial control prior to execution of current feedback control, for example, a third fixed duty (for example, 20 ms) larger than the first fixed duty over a longer time than the first fixed DUTY control. The third fixed DUTY control for supplying the initial power to the motor 13 is executed with a duty of 40% corresponding to a current of 14A in between.
Next, in step S11, the first control is performed to ignore the detection signal of the rotation angle sensor 32 and cause the current supplied to the motor 13 to follow the target current by the current feedback control based on the detection signal of the current sensor 33. To do.

Next, in step S12, it is determined whether a pre-crash request has not been output.
If the determination result is “NO”, the determination process of step S12 is repeatedly executed.
On the other hand, when the determination result is “YES”, the execution of the first control is ended, and the process proceeds to Step S13.

  Next, in step S13, as control for switching the connection state of the power transmission mechanism 12 by the clutch 11 to the cutoff state, for example, a fourth fixed duty (for example, between 200 ms) over a longer time than the second fixed DUTY control. The fourth fixed DUTY control (reverse rotation) is executed to reverse the motor 13 with a duty of 25% corresponding to a current of 7.5 A across the motor.

  Next, in step S14, the reverse rotation of the motor 13 is stopped and the process proceeds to the end.

Next, in step S15, it is determined whether or not an ON signal is output from the buckle switch 31.
If this determination is “YES”, the flow proceeds to step S 17 described later.
On the other hand, if this determination is “NO”, the flow proceeds to step S16.
In step S16, the storage operation of winding the webbing 5 to the predetermined full storage position is performed by the belt reel 10 while assisting with the driving force of the motor 13, and the process proceeds to the end.

Next, in step S17, as predetermined initial control prior to the execution of the rotation angle feedback control, for example, a fifth fixed duty larger than the first fixed duty (for example, 30% corresponding to a current of 8A for 10 ms) The fifth fixed DUTY control for supplying the initial power to the motor 13 is executed according to the duty).
Next, in step S18, the rotation angle of the motor 13 is caused to follow the target rotation angle by rotation angle feedback control based on the detection signal of the rotation angle sensor 32.

Next, in step S19, the current (drive current) supplied to the motor 13 is equal to or greater than a predetermined current (for example, a current that causes the tension acting on the webbing 5 to become a predetermined tension required for removing slack, such as 3A). It is determined whether or not.
If the determination result is “NO”, the determination process of step S19 is repeatedly executed.
On the other hand, if this determination is “YES”, the execution of the rotation angle feedback control is terminated, and the process proceeds to Step S20.

  Next, in step S20, as control for switching the connection state of the power transmission mechanism 12 by the clutch 11 to the cutoff state, for example, a sixth fixed duty larger than the second fixed duty (for example, a current of 8 A over 100 ms). The sixth fixed DUTY control (reverse rotation) that reversely rotates the motor 13 with a corresponding duty of 30% or the like is executed.

Next, in step S21, it is determined whether or not the pull-out amount of the webbing 5 has reached a predetermined pull-out amount.
If the determination result is “NO”, the determination process of step S21 is repeatedly executed.
On the other hand, if this determination is “YES”, the flow proceeds to step S22.
Next, in step S22, the reverse rotation of the motor 13 is stopped.
Next, in step S23, it is determined whether a pre-crash request has been output.
If this determination is “NO”, the flow returns to step S 01 described above.
On the other hand, if this determination is “YES”, the flow proceeds to step S24.

Next, in step S24, as predetermined initial control prior to the execution of the rotation angle feedback control, for example, a seventh fixed duty larger than the third fixed duty (for example, 60% corresponding to a current of 18 A over 20 ms) The seventh fixed DUTY control for supplying the initial power to the motor 13 by the duty) is executed.
Next, in step S25, the rotation angle of the motor 13 is caused to follow the target rotation angle by rotation angle feedback control based on the detection signal of the rotation angle sensor 32.

Next, in step S26, it is determined whether a pre-crash request is not output.
If the determination result is “NO”, the determination process of step S26 is repeatedly executed.
On the other hand, if the determination result is “YES”, the execution of the rotation angle feedback control is terminated, and the process proceeds to Step S27.

  Next, in step S27, as control for switching the connection state of the power transmission mechanism 12 by the clutch 11 to the cutoff state, for example, an eighth fixed duty that is the same as the fourth fixed duty (for example, 7.5 A over 200 ms) The eighth fixed DUTY control (reverse rotation) is performed to reverse the motor 13 by a duty of 25% corresponding to the current.

  Next, in step S28, the reverse rotation of the motor 13 is stopped and the process proceeds to the end.

As described above, according to the seat belt device 1 according to the present embodiment, when it is determined that the possibility of occurrence of the collision is equal to or greater than the predetermined value, the first control is executed, thereby causing the motor 13 to be excessive. Whether or not the possibility of a collision is equal to or higher than a predetermined value can be monitored at an appropriate frequency and timing while preventing a current from being applied.
On the other hand, if the possibility of occurrence of a collision is determined to be greater than or equal to a predetermined value, the second control is executed to ensure that the rotation angle sensor 32 is abnormal while ensuring the desired quietness and comfort. Can be monitored at an appropriate frequency and timing.
Thus, the motor 13 can be appropriately controlled according to each monitoring result.

That is, according to the first control, the processing load required for the diagnosis of the rotation angle sensor 32 can be reduced, and the processing capability of the control device 23 can be increased in addition to the control for driving the motor 13, and the occurrence of a highly urgent collision is possible. Can be allocated to monitoring whether or not the property is greater than or equal to a predetermined value.
On the other hand, according to the second control, the processing load required for monitoring whether or not the possibility of occurrence of a collision is a predetermined value or more is reduced, and the processing capability of the control device 23 is added to the control for driving the motor 13. Thus, it is possible to distribute the monitoring to the presence or absence of abnormality of the rotation angle sensor 32.
As a result, the processing capability of the control device 23 is given priority in each situation by switching and executing the rotation angle feedback control and the current feedback control depending on whether or not the possibility of the collision is a predetermined value or more. It is possible to efficiently distribute the processing to a high degree.

Further, the rotation state of the motor 13 can be stabilized to a desired constant state by the rotation angle feedback control. Thereby, for example, desired quietness and comfort can be ensured regardless of individual differences of the power transmission mechanism 12 or fluctuations in the voltage applied to the motor 13.
Further, by combining the rotation angle feedback control with the control for regulating the current supplied to the motor 13, an excessive current is supplied to the motor 13 even when the rotation angle sensor 32 is abnormal. Can be prevented.

  In addition, when the current feedback control is executed, it is possible to prevent an excessive current from being supplied to the motor 13 even if the detection result of the rotation angle sensor 32 is ignored. Thereby, the processing load required for the diagnosis of the rotation angle sensor 32 can be reduced, and the processing capability of the control device 23 is monitored to determine whether or not the possibility of occurrence of a collision is higher than a predetermined value. Can be allocated.

Further, even when the power supply voltage of the power supply 22 is less than a predetermined voltage, the webbing 5 can be appropriately controlled by the rotation angle feedback control, and desired safety can be ensured without giving a sense of incongruity to the occupant. .
For example, even if it is difficult to stabilize the rotation state of the motor 13 by current feedback control due to insufficient voltage applied to the motor 13, the rotation state of the motor 13 can be set to a desired value by rotation angle feedback control. It can be stabilized in a constant state.
Thereby, for example, desired quietness and comfort can be ensured regardless of individual differences of the power transmission mechanism 12 or fluctuations in the voltage applied to the motor 13.

Furthermore, before starting the execution of the current feedback control or the rotation angle feedback control, by energizing the motor 13 with a constant current with a fixed duty, the winding of the webbing 5 starts suddenly as the execution of each feedback control starts. Can be prevented. Thereby, it is possible to prevent the winding of the webbing 5 from giving a sense of incongruity to the occupant.
Further, for example, the current supplied to the motor 13 when the power supply voltage of the power supply 22 is less than a predetermined voltage is made larger than the current supplied to the motor 13 when the power supply voltage of the power supply 22 is equal to or higher than the predetermined voltage. Thus, a desired initial power can be ensured by compensating for the decrease in the power supply voltage by increasing the current.

Furthermore, even if the power supply voltage of the power supply 22 is less than the predetermined voltage, the power transmission mechanism 12 can be accurately switched from the connected state to the disconnected state while preventing the motor 13 from rotating in the reverse direction excessively. .
For example, in a state where it is difficult to stabilize the rotational state of the motor 13 due to an individual difference of the power transmission mechanism 12 or a variation in the voltage applied to the motor 13 due to a lack of voltage applied to the motor 13. Even in such a case, the reverse rotation of the motor 13 can be stopped at an appropriate timing in accordance with the pulling amount of the webbing 5.

  In the above-described embodiment, the motor control unit 42 uses the determination result of whether or not the power supply voltage detected by the voltage sensor 34 is equal to or higher than the predetermined voltage, instead of performing various processes. A determination result as to whether the supplied power is equal to or higher than a predetermined power may be used.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the configuration of the above-described embodiment is merely an example, and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Seat belt apparatus 5 Webbing 10 Belt reel 11 Clutch (connection / disconnection means)
13 Motor 22 Power supply (Power supply means)
32 Rotation angle sensor (Rotation angle detection means)
33 Current sensor (current detection means)
34 Voltage sensor (electric power detection means)
41 Collision prediction unit (collision prediction means)
42 Motor controller (control means)

Claims (4)

A belt reel on which a webbing for restraining a vehicle occupant is wound;
A motor for rotationally driving the belt reel;
Rotation angle detection means for detecting the rotation angle of the motor;
Current detecting means for detecting a current supplied to the motor;
Control means for controlling the current supplied to the motor;
A collision prediction means for determining whether or not the possibility of occurrence of a collision between the vehicle and an object outside the vehicle is a predetermined value or more;
With
The control means includes
If it is determined by the collision prediction means that the possibility of occurrence of the collision is greater than or equal to the predetermined value, the detection result of the rotation angle detection means is ignored, and current feedback based on the detection result of the current detection means Performing a first control for causing the current supplied to the motor to follow the target current by the control;
The rotation angle of the motor is set to the target rotation by the rotation angle feedback control based on the detection result of the rotation angle detection unit, except when the collision prediction unit determines that the possibility of the collision is greater than or equal to the predetermined value. A seatbelt device that performs second control for causing a current to be supplied to the motor to be regulated within a predetermined current range based on a detection result of the current detection means, following a corner. Power supply means for supplying power to the motor;
Power detection means for detecting the supply power of the power supply means,
The control means includes
The rotation angle feedback control is executed without executing the current feedback control when the supplied power detected by the power supply means is less than a predetermined power. Seat belt device. The control means includes
Executing the first control and the second control when the supply power detected by the power supply means is equal to or greater than the predetermined power;
Prior to the execution of the current feedback control and the rotation angle feedback control, an initial control for supplying initial power to the motor is performed,
The initial power when the supply power detected by the power supply means is less than the predetermined power, and the initial power when the supply power detected by the power supply means is greater than or equal to the predetermined power. The seat belt device according to claim 2, wherein the seat belt device is enlarged. Interposed between the motor and the belt reel, the motor and the belt reel are in a connected state triggered by rotation of the motor in one direction, and the motor and the belt triggered by rotation in the reverse direction of the motor It has connection / disconnection means to cut off the belt reel,
The control means includes
When the supply power detected by the power supply means is less than the predetermined power when rotating the motor in the reverse direction, the webbing pull-out amount is based on the detection result of the rotation angle detection means. The seatbelt device according to claim 2 or 3, wherein the rotation in the reverse direction is stopped when the amount exceeds a predetermined pull-out amount.

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