JP6631442B2 - Vehicle occupant restraint system - Google Patents

Description

  The present invention relates to a vehicle occupant restraint system.

  2. Description of the Related Art Vehicle occupant restraint systems for securing the occupant's body by increasing the tension of the webbing (seat belt) before and during a vehicle collision to increase the safety of the occupant are equipped in recent vehicles. There are various modes of restraining an occupant. As an example, a method of operating a pretensioner using explosives at the time of a vehicle collision and restraining the occupant's body to a seat is known.

  Although the occupant's body is thrown forward by inertia during a vehicle collision, the webbing is wound around a spool by an explosive-type pretensioner to restrain the occupant's body, so that the occupant's body can be held on the seat. However, if the body of the occupant thrown out by inertia due to the restraint by the webbing is fixed, the chest of the occupant may be subjected to strong compression (chest bending compression) by the webbing. If the chest flexion pressure is too strong, the occupant may be injured. Therefore, the vehicle occupant restraint device may be provided with a force limiter mechanism for appropriately relaxing the occupant restraint by the webbing.

  The force limiter mechanism relieves the restraint of the occupant by the webbing by pulling out the webbing wound on the spool when the chest flexion compression becomes excessive.

  Further, in a traffic accident, after a primary collision, which is the first vehicle collision, a secondary collision may occur due to a rear-end collision with a subsequent vehicle. After the above-mentioned force limiter mechanism is operated, the webbing is in a loosened state, and it is difficult to hold the occupant's body on the seat in a secondary collision in the state as it is. Patent Literature 1 discloses an invention of a seat belt control system for restraining an occupant's body again to a seat by winding up webbing by a motor as a countermeasure against a secondary collision after the explosive pretensioner is operated at the time of a primary collision. It has been disclosed.

JP-A-2005-096400

  However, when the impact of the primary collision is not strong, the explosive pretensioner may not operate. The invention of the seatbell control system disclosed in Patent Literature 1 winds the webbing by a motor as a measure against secondary collision on the premise that the explosive pretensioner is operated in primary collision. Therefore, in the invention disclosed in Patent Literature 1, when the explosive pretensioner does not operate in the primary collision, it may be difficult to hold the occupant's body on the seat in the secondary collision. .

  An object of the present invention is to provide a vehicle occupant restraint device that reliably winds up a webbing (seat belt) when there is a possibility of a secondary collision in consideration of the above fact.

The vehicle occupant restraint device according to claim 1, wherein a motor retractor capable of winding a seat belt by rotation of a motor, a sensor group capable of detecting a vehicle collision and a vehicle collision, and rotating the motor at high speed A first winding control for winding the seatbelt and a second winding control for winding the seatbelt by rotating the motor at a lower speed than the first winding control. And an executable control unit, wherein the control unit executes the first winding control when the vehicle collision is detected based on a detection result of the sensor group. If not, and there is a risk of a vehicle secondary collision, the second winding control is executed .

  The vehicle occupant restraint device according to the first aspect causes the drive circuit to generate a voltage for rotating the motor so as to wind up the seat belt when there is still a risk of a secondary vehicle collision after the vehicle collision.

  The vehicle occupant restraint device according to the first aspect of the present invention reliably winds up the seat belt when there is a risk of a secondary collision due to the rotation of the motor.

A vehicle occupant restraint device according to a second aspect is the vehicle occupant restraint device according to the first aspect, wherein the drive circuit generates a voltage for rotating the motor , An opening detection unit that detects that a door of the vehicle is opened, wherein the motor retractor is capable of pulling out the seat belt by rotation of the motor in a direction opposite to a direction in which the seat belt is wound, The drive circuit generates a voltage for rotating the motor in the reverse direction, the control unit determines that the occupant is not conscious based on a detection result of the consciousness detection unit after the vehicle collision, and When the opening detection unit detects that the door of the vehicle is opened, the driving circuit is controlled to generate a voltage for rotating the motor in the reverse direction.

  In the vehicle occupant restraint device according to the second aspect, when the occupant is not conscious, the restraint of the seat belt can be relaxed by rotating the motor when the door of the vehicle is opened.

  According to a third aspect of the present invention, in the vehicle occupant restraint apparatus according to the second aspect, the consciousness detection unit includes a rotation angle detection unit that detects a rotation angle of an output shaft of the motor, and the control unit includes When the drive circuit generated a voltage for rotating the motor so as to wind and pull out the seat belt, the rotation angle of the output shaft detected by the rotation angle detection unit changed linearly. In this case, it is determined that the occupant is not conscious.

  The vehicle occupant restraint device according to claim 3, when the occupant sits down and changes the rotation angle of the output shaft of the motor in a non-linear manner when the motor is rotated to change the restraining force of the seat belt. It is determined that the occupant is conscious, and when the rotation angle of the output shaft of the motor changes linearly, it can be determined that the occupant is not conscious. In the linear case, a linear change such as a linear function is recognized in a narrow sense, but in the present application, the change in the rotation angle in time series does not have a maximum value or a minimum value. If such is the case, it is determined to be linear. Conversely, when the change of the rotation angle in the time series is not uniform having the maximum value or the minimum value, it is determined to be non-linear.

  According to a fourth aspect of the present invention, in the vehicle occupant restraint apparatus according to the second aspect, the consciousness detection unit includes a vehicle interior camera that acquires image data of the occupant's face, and the control unit includes the control unit, The presence or absence of the occupant's consciousness is determined based on the image data acquired by the vehicle interior camera.

  The vehicle occupant restraint device according to claim 4 can determine whether the occupant is conscious by performing image processing on the image data of the occupant's face acquired by the camera in the vehicle compartment by a known method.

  According to the vehicle occupant restraint device of the first aspect, when there is still a possibility of a secondary collision of the vehicle after both collisions, the drive circuit generates a voltage for rotating the motor so as to wind up the seat belt. Thus, there is an effect that the seat belt can be reliably taken up when there is a possibility of a secondary collision.

  According to the vehicle occupant restraint device of the second aspect, when the occupant is not conscious, the rescue of the occupant can be reduced by rotating the motor when the door of the vehicle is opened to loosen the restraint of the seat belt. This has the effect of being easier.

  According to the vehicle occupant restraint device of the third aspect, it is possible to determine the presence or absence of the occupant's consciousness from the aspect of the change in the rotation angle of the output shaft of the motor.

  According to the vehicle occupant restraint device of the fourth aspect, it is possible to determine the presence or absence of the occupant's consciousness from the image data of the occupant's face.

1 is a block diagram showing an example of a schematic configuration of a vehicle occupant restraint device according to an embodiment of the present invention. It is a block diagram showing an example of a circuit of a vehicle occupant restraint device concerning an embodiment of the invention. 4 is a flowchart illustrating an example of a process of a seat belt retractor control circuit of the vehicle occupant restraint device according to the embodiment of the present invention. 4 is a flowchart illustrating an example of a secondary collision handling process in the vehicle occupant restraint device according to the embodiment of the present invention.

  Hereinafter, a vehicle occupant restraint system 10 according to the present embodiment will be described with reference to FIGS. In FIG. 1, a solid line is a power line through which power is supplied, and a broken line is a signal line through which a control signal is supplied. As shown in FIG. 1, the vehicle occupant restraint device 10 is a device that restrains the occupant 12 with a seat belt (webbing 30).

  The vehicle occupant restraint system 10 includes a seat belt retractor (motor retractor) 20, a webbing 30, a seat belt retractor drive circuit 50 (hereinafter abbreviated as "drive circuit 50"), a seat belt retractor control circuit 60 (hereinafter, "control circuit"). 60 "), a vehicle-mounted battery 80, a vehicle ECU (Electronic Control Unit) 82, and a sensor group 90.

  As shown in FIG. 1, one end 30A side of the webbing 30 is connected to a lower anchor 32 fixed to a vehicle floor or a seat cushion frame. The other end 30 </ b> B side of the webbing 30 is configured to be rollable by the seat belt retractor 20, and the webbing 30 pulled out from the seat belt retractor 20 is inserted into the shoulder anchor 34.

  A tongue plate 36 is provided between the shoulder anchor 34 and the lower anchor 32 of the webbing 30. The tongue plate 36 is detachable from a buckle 38 provided inside the seat cushion 14A of the seat 14 in the vehicle width direction.

  As shown in FIG. 1, the webbing 30 pulled out from the seat belt retractor 20 is disposed from the left shoulder of the occupant 12 to the left chest, right abdomen and right front waist via the shoulder anchor 34, and the tongue plate 36 is buckled. By being engaged with 38, the webbing 30 holds the body of the occupant 12 on the seat 14.

  The battery 80 is a secondary battery used as a power source for starting the engine of the vehicle and for electric components of the vehicle, and is a lead storage battery having a nominal voltage of 12 V as an example.

  The vehicle ECU 82 is a control device that controls the engine, electrical components, and other accessories of the vehicle, and includes a processor that is an arithmetic processing device, a storage device, and the like. In the description of the present embodiment, a sensor group 90 for detecting a vehicle collision or the like is connected to the vehicle ECU 82, and when the possibility of a vehicle collision is detected by the sensor group 90, the motor of the seat belt retractor 20 is turned on. The webbing 30 is wound around the spool 24 by being driven to remove the slack of the webbing 30. Further, at the time of a vehicle collision, the motor of the seat belt retractor 20 is rotated at a high speed so that the webbing 30 is rapidly wound up. In the present embodiment, by using a pretensioner driven by a motor, as an example, the webbing 30 wound around the spool 24 by the forward rotation of the motor is pulled out from the spool 24 by rotating the motor in the reverse direction, and the occupant 12 Enables the release of physical constraints. The gunpowder type pretensioner cannot be restarted once it has been operated, but the motor driven pretensioner reversibly performs restraint of the occupant's body and release of the restraint by forward and reverse rotation of the motor. It becomes possible.

  The description of “forward rotation” and “reverse rotation” of the motor in the present embodiment is for convenience. In the present embodiment, as an example, the rotation direction of the motor for winding the webbing 30 is referred to as “forward rotation”, and the rotation direction of the motor for extracting the webbing 30 is referred to as “reverse rotation”. The explanation has been simplified.

  A force limiter mechanism 40 is provided inside the spool 24. The force limiter mechanism 40 has a torsion bar 40A serving as a load absorbing member. When the tensile load applied to the webbing 30 exceeds a predetermined value, the webbing 30 is pulled out while torsionally deforming the torsion bar 40A. The configuration is such that the spool 24 is rotated at the same time.

  The sensor group 90 connected to the vehicle ECU 82 includes, for example, a millimeter wave radar 90A, a laser radar 90B, an acceleration sensor 90C, a vehicle-mounted camera 90D, a vehicle interior camera 90E, a door sensor 90F, and a rotation angle sensor 90G. Among the sensor group 90, the one that detects the possibility of a vehicle collision and detects a vehicle collision is a millimeter wave radar 90A, a laser radar 90B, an acceleration sensor 90C, and a vehicle-mounted camera 90D. In the present embodiment, among the sensor group 90, a sensor that detects the possibility of a vehicle collision and detects a vehicle collision includes at least one or more of a millimeter-wave radar, a laser radar, and an on-board camera 90D, and an acceleration sensor. Is done.

  The millimeter wave radar 90A includes a front millimeter wave radar that detects a distance to a front obstacle, a front millimeter wave radar that detects a distance to a front side obstacle, and a rear millimeter that detects a distance to a rear obstacle. Wave radar, including rear-side millimeter-wave radar that detects the distance to rear-side obstacles.

  The front millimeter wave radar is provided, for example, near the center of the front grill of the vehicle, and the front side millimeter wave radar is provided near the both ends in the vehicle width direction in the bumper, and emits millimeter waves to the front and the front side of the vehicle, respectively. Thus, the radio wave reflected from the object is received, and the distance to the object, the relative speed to the own vehicle, and the like are measured based on the propagation time, the frequency difference generated by the Doppler effect, and the like. Also, the rear millimeter wave radar and the rear side millimeter wave radar are provided on the rear bumper of the vehicle, etc., and receive the radio wave reflected from the target by emitting the millimeter wave to the rear and the rear side of the vehicle, respectively. The distance to the object, the relative speed to the own vehicle, and the like are measured based on the propagation time, the frequency difference caused by the Doppler effect, and the like.

  The laser radar 90B is a device that irradiates a laser beam having a shorter wavelength than the millimeter wave toward the front of the vehicle to detect an obstacle, and can relatively easily detect a nonmetallic object that is difficult to detect with the millimeter wave radar. When the laser light transmitted from the laser radar is reflected by an obstacle, the wavelength and the phase change. Therefore, the vehicle ECU 82 calculates the presence or absence of the obstacle and the distance to the obstacle based on the change.

  The in-vehicle camera (stereo camera) 90D is provided, for example, in the vehicle interior near the center above the front windshield glass, photographs the front of the vehicle, detects nearby obstacles, and measures the distance to the obstacles.

  The acceleration sensor is a sensor that is provided at a predetermined position on the left or right front side member or the radiator support, and detects an acceleration generated by a collision with a collision target vehicle bumper.

  The vehicle interior camera 90E is a camera for photographing the state of the occupant in the vehicle interior, and particularly acquires image data of the face of the occupant in the driver's seat. The acquired image data is output to the vehicle ECU 82 or an image processing dedicated processor (not shown), and the vehicle ECU 82 or the image processing dedicated processor determines the presence or absence of the occupant by known image processing.

  The door sensor 90F is a sensor that detects the open / closed state of the door of the vehicle. For example, a magnetic sensor such as a hall sensor or an MR sensor that detects a magnetic field of a sensor magnet (not shown) provided on the door side is used.

  As an example, the door sensor 90F is disposed so as to face a sensor magnet provided on the door side with a predetermined gap therebetween when the door is closed. When the door is opened and the distance between the sensor magnet and the door sensor 90F increases, the strength of the magnetic field detected by the door sensor 90F decreases. Further, when the door is closed and the sensor magnet and the door sensor 90F face each other while being separated by the above-mentioned predetermined gap, the intensity of the magnetic field detected by the door sensor 90F becomes maximum. The vehicle ECU 82 determines the open / closed state of the door from the change in the magnetic field.

  The rotation angle sensor 90G is a magnetic sensor that detects a magnetic field of a sensor magnet provided at an end of an output shaft of a motor that rotates the spool 24, and an MR sensor or the like is used as an example. When the output shaft of the motor rotates, the magnetic field of the sensor magnet changes according to the rotation. The vehicle ECU 82 calculates the rotation angle of the output shaft of the motor from the change in the magnetic field detected by the rotation angle sensor 90G. The rotation angle sensor 90G is originally provided in the seat belt retractor 20, but is shown near the vehicle ECU 82 for convenience in FIG. An example of the arrangement of the rotation angle sensor 90G will be described with reference to FIG.

  The vehicle ECU 82 obtains the detection results of the millimeter wave radar 90A, the laser radar 90B, the acceleration sensor 90C, and the on-vehicle camera 90D and performs a collision prediction. Various known techniques can be applied to the collision prediction, and a detailed description thereof will be omitted.

  The drive circuit 50 is a circuit that generates a voltage to be applied to the motor of the seatbelt retractor 20, and includes an H-bridge circuit including a switching element such as an FET (field effect transistor), as described later. The switching elements constituting the H-bridge circuit of the drive circuit 50 are controlled by the control circuit 60.

  The control circuit 60 is a so-called microcomputer, and controls the switching elements of the drive circuit 50 described above.

  FIG. 2 is a block diagram showing an example of a circuit of the vehicle occupant restraint device 10 according to the present embodiment. Control circuit 60 controls drive circuit 50 based on a command from vehicle ECU 82. The drive circuit 50 is an H-bridge circuit composed of FETs 52A, 52B, 52C, and 52D, each of which is an N-type FET. The drive circuit 50 connects the source (S) of the FET 52A and the drain (D) of the FET 52C and connects the FET 52B. Are connected to the drain of the FET 52D. The drains of the FETs 52A and 52B are connected to the positive electrode of a battery 80 mounted on the vehicle, and the sources of the FETs 52C and 52D are grounded via a current detection unit 70 described later.

  Each of the N-type FETs included in the drive circuit 50 functions as a switch in which when a positive charge voltage is applied to the gate (G), a current can flow between the drain and the source (on state). In the present embodiment, when the motor 22 of the seat belt retractor 20 winds the webbing 30 around the spool 24, the control circuit 60 outputs a positive charge control signal to each of the gates of the FET 52A and the FET 52D. Then, the FET 52D is turned on, and the motor 22 is rotated forward. Further, by outputting a control signal of a positive charge from the control circuit 60 to each gate of the FET 52B and the FET 52C, the FET 52B and the FET 52C can be turned on and the motor 22 can be rotated in the reverse direction.

  When the motor 22 is rotated forward, one of the FET 52A and the FET 52D of the drive circuit 50 is intermittently turned on and off to generate a pulse voltage and perform PWM (pulse width modulation) applied to the motor 22. . Similarly, when the motor 22 is rotated in the reverse direction, one of the FET 52B and the FET 52C of the drive circuit 50 is turned on and off intermittently to generate a pulse-like voltage and perform PWM for applying the pulse-like voltage to the motor 22. As described above, the N-type FET is turned on when a control signal of a positive charge is applied to the gate. Therefore, the control circuit 60 outputs a pulse-shaped control signal that repeats on and off intermittently to any of the FETs 52A and 52D. By outputting the signal to one of the gates or one of the gates of the FET 52B and the FET 52C, the drive circuit 50 executes the above-described PWM voltage generation.

  By making the voltage applied to the motor 22 into a pulse shape, the effective voltage value of the voltage applied to the motor 22 is controlled. If the voltage applied to the motor 22 is not controlled, the current value of the coil of the motor 22 (hereinafter abbreviated as “motor current”) exceeds the rated current value, and the motor 22 may be burned. By generating the applied voltage by PWM, it is possible to rotate the motor 22 at high speed while suppressing the effective voltage value to prevent the motor 22 from burning out.

  The current detection unit 70 amplifies a potential difference between both ends of the shunt resistor 70A having a resistance value of about 0.2 mΩ to several Ω with an amplifier 70B and outputs a voltage value proportional to the current of the shunt resistor 70A as a signal. The control circuit 60 calculates the motor current based on the signal output from the current detection unit 70. When there is a possibility that the calculated motor current may exceed the rated current value of the motor 22, the control circuit 60 outputs a control signal for shortening the time during which the switching element of the drive circuit 50 is turned on intermittently. With such a control signal, the drive circuit 50 reduces the pulse width of the voltage generated by the PWM to reduce the effective voltage value, so that the motor current can be prevented from exceeding the rated current value.

  The motor 22 is a DC motor with a brush that is driven by direct current. One end of a coil is connected to the source of the FET 52A and the drain of the FET 52C that form the drive circuit 50, and the other end of the coil forms the drive circuit 50. The source is connected to the source of the FET 52B and the drain of the FET 52D.

  The output shaft 92 of the motor 22 is connected to the spool 24 of the seat belt retractor 20. When the motor 22 rotates forward, the webbing 30 is wound on the spool 24. When the motor 22 rotates in the reverse direction, the webbing 30 is pulled out from the spool 24.

  In the present embodiment, when the motor 22 is rotated forward at a high speed and the webbing 30 is rapidly wound at the time of a vehicle collision, the voltage applied to the motor 22 is increased by increasing the pulse width of the voltage generated by PWM. Increase the effective voltage value of the voltage. However, when it is difficult to rotate the motor 22 at a high speed with the voltage of the battery 80 as the power supply, a configuration capable of supplying a higher voltage than the battery 80 at the time of a vehicle collision is appropriately used.

  For example, a configuration is used in which a capacitor for storing the battery 80 is provided in the event of a vehicle collision, and the power obtained by discharging the capacitor in a vehicle collision is boosted by a booster circuit such as an insulated DC-DC converter. Alternatively, a charge pump including a plurality of capacitors may be used. The charge pump generates a high voltage by charging the plurality of capacitors in a state where the plurality of capacitors are connected in parallel, and switching the connection of the plurality of capacitors in series to discharge. However, when the power is boosted using the above configuration, the risk of the motor current exceeding the rated current increases, so it is desirable to control the drive circuit 50 based on the detection result of the current detection unit 70 described above.

  The rotation angle sensor 90G is provided to face a sensor magnet 94 provided at an end of the output shaft 92 which is also an end of the spool 24. When the spool 24 and the output shaft 92 rotate, the sensor magnet 94 also rotates, and the rotation changes the magnetic field detected by the rotation angle sensor 90G. The vehicle ECU 82 calculates the rotation angle of the output shaft 92 from the change in the magnetic field.

  Next, the operation of the present embodiment will be described. FIG. 3 is a flowchart illustrating an example of a process of control circuit 60 of vehicle occupant restraint device 10 according to the present embodiment. In step 300, it is determined whether there is a possibility of a vehicle collision. In the present embodiment, as an example, the case where the vehicle ECU 82 operates the automatic brake of the vehicle based on the detection results of the millimeter wave radar 90A, the laser radar 90B, and the vehicle-mounted camera 90D is defined as a case where there is a possibility of a vehicle collision. An affirmative determination is made at 300. If a negative determination is made in step 300, the detection by the millimeter wave radar 90A, the laser radar 90B, the acceleration sensor 90C, and the in-vehicle camera 90D is continued.

  In the case of an affirmative determination in step 300, the drive circuit 50 is controlled so that the motor 22 rotates forward at low speed in step 302. The control circuit 60 outputs a PWM control signal to the drive circuit 50 so that the drive circuit 50 generates a voltage for rotating the motor 22 forward at an optimum rotation speed for removing the slack of the webbing 30.

  In step 304, it is determined whether or not the vehicle ECU 82 has detected a vehicle collision based on the detection result of the acceleration sensor 90C. If an affirmative determination is made in step 304, the drive circuit 50 is controlled so that the motor 22 is rotated forward at high speed in step 306. The control circuit 60 outputs a PWM control signal to the drive circuit 50 so that the drive circuit 50 generates a voltage for rotating the motor 22 at high speed. After the motor 22 is rotated at a high speed in step 306, the process ends.

  In the case of a negative determination in step 304, for example, when the vehicle collision is not detected and the millimeter wave radar 90A, the laser radar 90B, and the on-vehicle camera 90D no longer detect an obstacle, in step 308 the motor 22 Power supply to the power supply is stopped. Specifically, the output of the PWM control signal to the drive circuit 50 is stopped. After stopping the power supply from the battery 80 to the motor 22 in step 308, the procedure returns to step 300, and the detection by the millimeter wave radar 90A, the laser radar 90B, the acceleration sensor 90C, and the on-board camera 90D is continued.

  FIG. 4 is a flowchart illustrating an example of the secondary collision handling process in the vehicle occupant restraint device 10 according to the present embodiment. In step 400, it is determined whether or not the vehicle ECU 82 has detected the occurrence of a vehicle collision based on the detection result of the acceleration sensor 90C. If the determination is affirmative, the procedure proceeds to step 402. If a negative determination is made in step 400, the procedure proceeds to step 410.

In step 402, as shown in step 306 of FIG. 3, it is determined whether or not the motor 22 rotates at a high speed to operate the pretensioner. This is because when the impact of the vehicle collision detected by the acceleration sensor 90C or the like is weak, the pretensioner may not operate. Whether or not the pretensioner has been operated is determined based on a change in the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G. As an example, when the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G rapidly changes by a predetermined value or more in the forward rotation direction, it can be determined that the pretensioner has been activated. If a negative determination is made in step 402, it is determined in step 404 whether there is a possibility of a secondary collision. In step 404, an obstacle around the vehicle is detected by the millimeter wave radar 90A, the laser radar 90B, and the on-board camera 90D, and an affirmative determination is made when the obstacle is detected.

  In the case of an affirmative determination in step 404, after the motor 22 is rotated forward in step 406 to wind up the webbing 30, the procedure proceeds to step 410. If a negative determination is made in step 404, the procedure proceeds to step 410 without winding the webbing 30.

  If a negative determination is made in step 402, it is determined in step 408 whether or not the amount of withdrawal of the webbing 30 by the force limiter mechanism 40 is equal to or smaller than a threshold. The amount by which the webbing 30 is pulled out is calculated from the rotation angle of the output shaft 92 (spool 24) in the reverse rotation direction detected by the rotation angle sensor 90G. In the case of an affirmative determination in step 408, the procedure moves to step 410 because it is not necessary to wind up the webbing 30 in step 406. If a negative determination is made in step 408, the procedure proceeds to step 404, and it is determined whether there is a possibility of a secondary collision.

  In step 410, it is determined whether or not the occupant 12 is conscious. Whether the occupant 12 is conscious or not is determined by extracting the image data of the face of the occupant 12 obtained by the vehicle interior camera 90E by a known image processing technique such as edge extraction, and based on the extracted elements, the consciousness of the occupant 12 is determined. Determine the presence or absence. For example, if the position of the edge-extracted element does not move even after a predetermined time has elapsed, it is determined that the occupant 12 is not conscious.

  Alternatively, the presence or absence of the occupant 12 is determined based on the rotation of the motor 22 and the detection result of the rotation angle sensor 90G. Specifically, the restraining force of the webbing 30 is changed by rotating the motor 22 forward and backward, and the presence or absence of the occupant 12 is determined from the change in the rotation angle detected by the rotation angle sensor 90G at that time. If the occupant 12 is conscious, the occupant 12 exhibits resistance such as sitting down against the tightening of the webbing 30, so that the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G changes nonlinearly. When the occupant 12 is not conscious, the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G changes linearly because the occupant 12 does not resist the tightening of the webbing 30. In the linear case, a linear change such as a linear function is recognized in a narrow sense, but in the present embodiment, the change in the rotation angle in time series is a maximum value or a minimum value. If it is not uniform, it is determined to be linear. Conversely, when the change of the rotation angle in the time series is not uniform having the maximum value or the minimum value, it is determined to be non-linear.

  In step 410, either the determination using the above-described cabin camera 90E or the determination using the rotation angle sensor 90G may be used, but in the present embodiment, in order to improve the accuracy of the determination, The determination using the indoor camera 90E and the determination using the rotation angle sensor 90G are used together. If a negative determination is made in step 410, the process returns.

  If an affirmative determination is made in step 410, it is determined in step 412 whether or not the door of the vehicle has been opened by the door sensor 90F. In the present embodiment, a case where the door is opened without the occupant's 12 consciousness is regarded as a case where the door of the vehicle is opened for rescue. If a negative determination is made in step 412, the process returns.

  If an affirmative determination is made in step 412, the motor 22 is rotated in the reverse direction in step 414, and the process returns. When the occupant 12 is not conscious, the webbing 30 is loosened by rotating the motor 22 in the reverse direction to facilitate rescue of the occupant 12.

  As described above, according to the present embodiment, when there is a risk of a vehicle collision after a vehicle collision, the webbing 30 is reliably taken up by rotating the motor 22 in the forward direction, and the body of the occupant 12 is seated. 14 can be held.

  Further, according to the present embodiment, when the occupant 12 is not conscious after the vehicle collision and the door of the vehicle is opened, the motor 22 is rotated in the reverse direction to loosen the webbing 30 so that the occupant can be loosened. Facilitates 12 rescues.

Reference Signs List 10 vehicle occupant restraint device 12 occupant 14 seat 14A seat cushion 20 seat belt retractor (motor retractor)
22 motor 24 spool 30 webbing (seat belt)
50 seat belt retractor drive circuit 60 seat belt retractor control circuit 80 battery 82 vehicle ECU (control unit)
90 Sensor group 90A Millimeter wave radar 90B Laser radar 90C Acceleration sensor 90D In-vehicle camera 90E In-vehicle camera (consciousness detection unit)
90F Door sensor (open detection part)
90G rotation angle sensor (consciousness detection unit, rotation angle detection unit)

Claims (4)

A motor retractor capable of winding a seat belt by rotation of a motor,
A sensor group capable of detecting a vehicle collision and a vehicle collision,
A first winding control for rotating the motor at a high speed to wind the seat belt; and a second winding for winding the seat belt by rotating the motor at a lower speed than the first winding control. Control, and a control unit that can be switched and executed, a vehicle occupant restraint device comprising:
The control unit is configured to perform the second winding control based on a detection result of the sensor group, when the first winding control is not performed when the vehicle collision is detected, and when there is a possibility of a vehicle secondary collision. A vehicle occupant restraint device that performs winding control of a vehicle. A drive circuit for generating a voltage for rotating the motor,
An awareness detection unit for detecting the presence or absence of the occupant's awareness,
An open detection unit that detects that a vehicle door has been opened;
With
The motor retractor is capable of pulling out the seat belt by rotation of the motor in a direction opposite to a direction at the time of winding the seat belt,
The drive circuit generates a voltage for rotating the motor in the reverse direction,
The control unit, after the vehicle collision, when it is determined that the occupant is unconscious based on the detection result of the consciousness detection unit, and when it is detected that the door of the vehicle is opened by the open detection unit, The vehicle occupant restraint device according to claim 1, wherein the drive circuit controls the drive circuit to generate a voltage for rotating the motor in the reverse direction. The consciousness detection unit includes a rotation angle detection unit that detects a rotation angle of an output shaft of the motor,
The control unit is configured such that when the drive circuit generates a voltage for rotating the motor so as to wind and pull out the seat belt, the rotation angle of the output shaft detected by the rotation angle detection unit is linear. 3. The vehicle occupant restraint device according to claim 2, wherein it is determined that the occupant is unconscious when the vehicle occupant changes. The consciousness detection unit includes a vehicle interior camera that acquires image data of the occupant's face,
The vehicle occupant restraint device according to claim 2, wherein the control unit determines whether the occupant is conscious based on image data acquired by the vehicle interior camera.

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