JP2018034596A - Occupant restraint device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an occupant restraint device for a vehicle that reliably retracts webbing when there is a possibility of secondary collision.SOLUTION: When vehicular ECU 82 determines that a vehicle collision has occurred based on detection result of sensor group 90 and then the vehicular ECU 82 determines that there is a possibility of a vehicle collision, a seat belt retractor control circuit 60 controls a seat belt retractor drive circuit 50 to generate a voltage for rotating a motor 22 so as to retract webbing 30 with a spool 24.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle occupant restraint device.

  A vehicle occupant restraint device for restraining the occupant's body by increasing the tension of the webbing (seat belt) before the vehicle collision and during the vehicle collision is provided in recent vehicles. There are various modes for restraining the occupant. As an example, there is known a method of restraining the occupant's body to the seat by operating a pretensioner using explosives at the time of a vehicle collision.

  When the vehicle collides, the occupant's body is thrown forward due to inertia, but the occupant's body can be held on the seat by winding the webbing around the spool with the explosive pretensioner and restraining the occupant's body. However, if the occupant's body that is thrown out by inertia is restrained by webbing, the occupant's chest may be subjected to strong compression (chest deflection compression) by the webbing. If the chest deflection pressure is too strong, the occupant may be injured. Therefore, the vehicle occupant restraint device may be provided with a force limiter mechanism that appropriately relaxes occupant restraint due to webbing.

  The force limiter mechanism relaxes the restraint of the occupant by the webbing by pulling out the webbing wound around the spool when the chest deflection pressure becomes excessive.

  Further, in a traffic accident, there is a possibility that a secondary collision may occur due to a rear-end collision with a subsequent vehicle after the primary collision that is the first vehicle collision. Since the webbing is in a relaxed state after the above-described force limiter mechanism is operated, it is difficult to hold the occupant's body on the seat in a secondary collision in the state as it is. Patent Document 1 discloses an invention of a seat belt control system that re-restrains the occupant's body to a seat by winding a webbing with a motor as a countermeasure against a secondary collision after operating an explosive pretensioner at the time of a primary collision. It is disclosed.

Japanese Patent Laid-Open No. 2015-096400

  However, if 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 Document 1 winds webbing by a motor as a countermeasure against a secondary collision on the premise that the explosive pretensioner is operated in a primary collision. Therefore, in the invention disclosed in Patent Document 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. .

  In view of the above-described facts, an object of the present invention is to provide a vehicle occupant restraint device that reliably winds a webbing (seat belt) when there is a possibility of a secondary collision.

  The vehicle occupant restraint device according to claim 1 is a motor retractor that can wind up a seat belt by rotating a motor, a sensor group that can detect a vehicle collision and a vehicle collision, and a voltage that rotates the motor. And a control unit that controls the drive circuit to generate a voltage for rotating the motor when there is a possibility of a secondary vehicle collision after a vehicle collision based on the detection result of the sensor group. And.

  The vehicle occupant restraint device according to claim 1 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 possibility of a secondary vehicle collision after the vehicle collision.

  The vehicle occupant restraint device according to claim 1 reliably winds the seat belt when there is a possibility of a secondary collision due to the rotation of the motor.

  According to a second aspect of the present invention, there is provided a vehicle occupant restraint device according to the first aspect of the present invention, wherein the consciousness detection unit detects the presence or absence of the occupant's consciousness and the open detection unit detects that the vehicle door is opened The motor retractor is capable of pulling out the seat belt by rotating the motor in a direction opposite to that when the seat belt is wound, and the drive circuit rotates the motor in the reverse direction. A voltage is generated, and the control unit detects that the occupant is not conscious based on the detection result of the consciousness detection unit after the vehicle collision, and detects that the vehicle door is opened by the open detection unit. In this case, the drive 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 there is no consciousness of the occupant, the restraint of the seat belt can be loosened by rotating the motor when the vehicle door is opened.

  According to a third aspect of the present invention, in the vehicle occupant restraint device according to the second aspect, the consciousness detection unit includes a rotation angle detection unit that detects a rotation angle of the output shaft of the motor, and the control unit includes: The rotation angle of the output shaft detected by the rotation angle detector linearly changes when the drive circuit generates a voltage for rotating the motor so that the seat belt is wound and pulled out. In this case, it is determined that the passenger is not conscious.

  In the vehicle occupant restraint device according to claim 3, when the motor is rotated and the restraint force of the seat belt is changed, the occupant relaxes and the rotation angle of the output shaft of the motor changes nonlinearly. It can be determined that there is occupant consciousness, and it can be determined that there is no occupant consciousness when the rotation angle of the output shaft of the motor changes linearly. The linear case is a case where a linear change such as a linear function is recognized in a narrow sense, but in the present application, the change in the time series of the rotation angle does not have a maximum value or a minimum value. If so, it is determined to be linear. On the contrary, when the change in the rotation angle in time series is not uniform having a maximum value or a minimum value, it is determined to be non-linear.

  According to a fourth aspect of the present invention, in the vehicle occupant restraint device 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 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 or not the occupant is conscious by performing image processing on the image data of the occupant's face acquired by the in-vehicle camera by a known method.

  According to the vehicle occupant restraint device of the first aspect, in the case where there is still a possibility of a secondary vehicle collision after both collisions, the driving 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 wound when there is a possibility of a secondary collision.

  According to the vehicle occupant restraint device according to claim 2, when there is no consciousness of the occupant, the occupant can be rescued by rotating the motor to loosen the restraint of the seat belt when the vehicle door is opened. There is an effect that it becomes easy.

  According to the vehicle occupant restraint device of the third aspect, there is an effect that the presence or absence of the occupant's consciousness can be determined from the change in the rotation angle of the output shaft of the motor.

  According to the vehicle occupant restraint device of the fourth aspect, there is an effect that it is possible to determine whether or not the occupant is conscious from the image data of the occupant's face.

It is the block diagram which showed an example of schematic structure of the passenger | crew restraint apparatus for vehicles which concerns on embodiment of this invention. It is the block diagram which showed an example of the circuit of the passenger | crew restraint apparatus for vehicles which concerns on embodiment of this invention. It is the flowchart which showed an example of the process of the seatbelt retractor control circuit of the passenger | crew restraint apparatus for vehicles which concerns on embodiment of this invention. It is the flowchart which showed an example of the secondary collision response process in the passenger | crew restraint apparatus for vehicles which concerns on embodiment of this invention.

  Hereinafter, the vehicle occupant restraint device 10 according to the present embodiment will be described with reference to FIGS. 1 and 2. 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 device 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 referred to as “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, the one end 30 </ b> A side of the webbing 30 is connected to a lower anchor 32 fixed to the passenger compartment floor or the seat cushion frame. The other end 30 </ b> B side of the webbing 30 is configured to be rewound 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 attachable to and 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 on the left chest, right abdomen, and right front waist of the occupant 12 via a 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 an engine of a vehicle and electrical 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 equipment of the vehicle, and includes a processor that is an arithmetic processing unit, a storage device, and the like. In the description of the present embodiment, a sensor group 90 for detecting a vehicle collision 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 slack of the webbing 30 is removed by driving the webbing 30 around the spool 24. 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 quickly wound. 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 normal rotation of the motor is pulled out from the spool 24 by rotating the motor in the reverse direction. It makes it possible to release body restraints. The explosive pretensioner cannot be re-actuated once activated, but the motor-driven pretensioner reversibly restrains the occupant's body and releases the restraint by rotating the motor forward and backward. It becomes possible.

  In the present embodiment, the description of “forward rotation” and “reverse rotation” of the motor is for convenience. In this embodiment, as an example, the rotation direction of the motor for winding the webbing 30 is “forward rotation” and the rotation direction of the motor for pulling out the webbing 30 is “reverse rotation”. The explanation is simplified.

  A force limiter mechanism 40 is provided inside the spool 24. The force limiter mechanism 40 has a torsion bar 40A that functions 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 twisting and deforming the torsion bar 40A. In this configuration, the spool 24 is rotated.

  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, an in-vehicle camera 90D, a vehicle interior camera 90E, a door sensor 90F, and a rotation angle sensor 90G. Among the sensor group 90, the millimeter wave radar 90A, the laser radar 90B, the acceleration sensor 90C, and the in-vehicle camera 90D detect the fear of the vehicle collision and the vehicle collision. In the present embodiment, the sensor that detects the risk of vehicle collision and the vehicle collision in the sensor group 90 includes at least one of millimeter wave radar, laser radar, and in-vehicle camera 90D, and an acceleration sensor. Is done.

  The millimeter wave radar 90A includes a front millimeter wave radar that detects a distance to an obstacle ahead, a front side millimeter wave radar that detects a distance to an obstacle ahead, and a rear millimeter that detects a distance to an obstacle behind. Includes wave radar and rear side millimeter wave radar to detect distance to obstacles on the back side.

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

  The laser radar 90B is a device that detects an obstacle by irradiating the front of the vehicle with laser light having a wavelength shorter than that of the millimeter wave, and can relatively easily detect a non-metallic object that is difficult to detect with the millimeter wave radar. When the laser beam transmitted from the laser radar is reflected by the obstacle, the wavelength and the phase change. Therefore, the vehicle ECU 82 calculates the presence / 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, and images the front of the vehicle to detect surrounding obstacles and measure the distance to the obstacles.

  The acceleration sensor is a sensor that is provided at a predetermined position of the left and right front side members or the radiator support, and detects an acceleration generated by a collision with a vehicle bumper to be collided.

  The vehicle interior camera 90E is a camera for photographing the state of the passenger in the vehicle interior, and in particular, acquires image data of the face of the passenger in the driver's seat. The acquired image data is output to the vehicle ECU 82 or a processor dedicated to image processing (not shown), and the vehicle ECU 82 or the processor dedicated to image processing determines the presence or absence of occupant awareness 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 arranged so as to face a sensor magnet provided on the door side with a predetermined gap in a state where 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. When the door is closed and the sensor magnet and the door sensor 90F face each other with the predetermined gap therebetween, the magnetic field intensity detected by the door sensor 90F is maximized. 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 the magnetic field of a sensor magnet provided at the end of the output shaft of the motor that rotates the spool 24. As an example, an MR sensor or the like is used. 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 illustrated 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 in-vehicle camera 90D and performs a collision prediction. Since various known techniques can be applied to the collision prediction, detailed description is omitted.

  The drive circuit 50 is a circuit that generates a voltage to be applied to the motor of the seat belt retractor 20, and includes an H-bridge circuit composed of switching elements such as FETs (field effect transistors), as will be 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 the circuit of the vehicle occupant restraint device 10 according to the present embodiment. The control circuit 60 controls the drive circuit 50 based on a command from the 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 source (S) of the FET 52A and the drain (D) of the FET 52C are connected to each other, and the FET 52B is connected. Are connected to the drain of the FET 52D. The drains of the FETs 52A and 52B are connected to the positive electrode of the on-vehicle battery 80, 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 constituting the drive circuit 50 functions as a switch that is in a state (ON state) in which the drain and the source can be energized when a positively charged voltage is applied to the gate (G). 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 the respective gates of the FET 52A and the FET 52D. And the FET 52D is turned on, and the motor 22 is rotated forward. Further, by outputting a positive charge control signal from the control circuit 60 to the respective gates of the FETs 52B and 52C, the FETs 52B and 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 / off to generate a pulse voltage and apply PWM (pulse width modulation) to be applied to the motor 22. . Similarly, when the motor 22 is rotated in the reverse direction, either one of the FET 52B and the FET 52C of the drive circuit 50 is intermittently turned on / off to generate a pulse voltage and perform PWM to be applied to the motor 22. As described above, since the N-type FET is turned on when a positive charge control signal is applied to the gate, the control circuit 60 applies a pulse-like control signal that repeatedly turns on and off intermittently to either the FET 52A or the FET 52D. By outputting to one of the gates or one of the gates of the FET 52B and the FET 52C, the drive circuit 50 executes the voltage generation by the above-described PWM.

  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”) may exceed the rated current value, and the motor 22 may burn out. By generating the voltage to be applied by PWM, it is possible to rotate the motor 22 at high speed while suppressing the effective voltage value and preventing the motor 22 from burning out.

  The current detector 70 amplifies the potential difference between both ends of the shunt resistor 70A having a resistance value of about 0.2 mΩ to several Ω by the 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 the calculated motor current may exceed the rated current value of the motor 22, the control circuit 60 outputs a control signal that shortens the time during which the switching element of the drive circuit 50 is intermittently turned on. With this control signal, the drive circuit 50 decreases the effective voltage value by reducing the pulse width of the voltage generated by PWM, so that the motor current can be prevented from exceeding the rated current value.

  The motor 22 is a DC motor with a brush driven by direct current, and one end of the coil is connected to the source of the FET 52A and the drain of the FET 52C constituting the drive circuit 50, and the other end of the coil constitutes the drive circuit 50. The source of the FET 52B and the drain of the FET 52D are connected to each other.

  The output shaft 92 of the motor 22 is connected to the spool 24 of the seat belt retractor 20, and when the motor 22 rotates forward, the webbing 30 is wound around the spool 24. Further, 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 high speed and the webbing 30 is rapidly wound at the time of a vehicle collision, the pulse width of the voltage generated by PWM is increased to be applied to the motor 22. Increase the effective voltage value of the voltage. However, when it is difficult to rotate the motor 22 at high speed with the voltage of the battery 80 as a power source, a configuration capable of supplying higher voltage power than the battery 80 at the time of a vehicle collision is appropriately used.

  For example, when there is a possibility of a vehicle collision, a configuration is used in which a capacitor for storing the battery 80 is provided and the electric power obtained by discharging the capacitor at the time of the vehicle collision is boosted by a boosting circuit such as an insulation type DC-DC converter. Alternatively, a charge pump including a plurality of capacitors may be used. The charge pump charges the plurality of capacitors in a state where the plurality of capacitors are connected in parallel, and switches the connection of the plurality of capacitors in series to generate a high voltage. However, when the electric power is boosted using the above configuration, the risk that the motor current exceeds the rated current is increased, 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 the end of the output shaft 92 that is also the end of the spool 24. When the spool 24 and the output shaft 92 rotate, the sensor magnet 94 also rotates, and the magnetic field detected by the rotation angle sensor 90G changes due to the rotation. The vehicle ECU 82 calculates the rotation angle of the output shaft 92 from the change in the magnetic field.

  Next, the operation of this embodiment will be described. FIG. 3 is a flowchart showing an example of processing of the control circuit 60 of the 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 activates the automatic brake of the vehicle based on the detection results of the millimeter wave radar 90A, the laser radar 90B, and the in-vehicle camera 90D Affirmative determination is made at 300. If the determination in step 300 is negative, detection by the millimeter wave radar 90A, laser radar 90B, acceleration sensor 90C, and in-vehicle camera 90D is continued.

  If the determination in step 300 is affirmative, the drive circuit 50 is controlled in step 302 so that the motor 22 is rotated forward at a low speed. The control circuit 60 outputs a PWM control signal to the drive circuit 50 so that the drive circuit 50 generates a voltage for causing the motor 22 to rotate in the forward direction at an optimum rotational 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 the determination in step 304 is affirmative, the drive circuit 50 is controlled in step 306 so that the motor 22 is rotated forward at high speed. 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 a high speed. After the motor 22 is rotated at a high speed in step 306, the process is terminated.

  In the case of negative determination in step 304, for example, when a vehicle collision is not detected and the millimeter wave radar 90A, laser radar 90B, and in-vehicle camera 90D no longer detect an obstacle, in step 308, from the battery 80 to the motor 22 Stop power supply to 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 is returned to step 300, and the detection by the millimeter wave radar 90A, the laser radar 90B, the acceleration sensor 90C, and the in-vehicle camera 90D is continued.

  FIG. 4 is a flowchart showing an example of a 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 the determination in step 400 is negative, the procedure is shifted to step 410.

  In step 402, as shown in step 306 of FIG. 3, it is determined whether or not the motor 22 has rotated at a high speed to operate the pretensioner. This is because the pretensioner may not operate when the impact of the vehicle collision detected by the acceleration sensor 90C or the like is weak. Whether or not the pretensioner is activated is determined by 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 suddenly changes in a positive rotation direction by a predetermined value or more, it can be determined that the pretensioner is activated. If the determination in step 402 is affirmative, 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 in-vehicle camera 90D. If an obstacle is detected, an affirmative determination is made.

  If the determination in step 404 is affirmative, the motor 22 is rotated forward in step 406 to wind up the webbing 30, and then the procedure is shifted to step 410. If the determination in step 404 is negative, the procedure is shifted to step 410 without winding the webbing 30.

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

  In step 410, it is determined whether or not the occupant 12 is conscious. The presence / absence of the occupant 12 is determined by extracting the elements from the image data of the occupant 12's face acquired by the in-vehicle camera 90E by a known image processing technique such as edge extraction and based on the extracted elements. Determine presence or absence. For example, if the position of the 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 restraint force by 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. If the occupant 12 is conscious, it shows resistance to squeezing the webbing 30 and the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G changes nonlinearly. When the occupant 12 is not conscious, since the webbing 30 is not resisted, the rotation angle of the output shaft 92 detected by the rotation angle sensor 90G changes linearly. Note that the linear case is a case where 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 has a maximum value or a minimum value. If there is no uniform, it is determined to be linear. On the contrary, when the change in the rotation angle in time series is not uniform having a maximum value or a minimum value, it is determined to be non-linear.

  In step 410, either the determination using the vehicle interior camera 90 </ b> E or the determination using the rotation angle sensor 90 </ b> G may be used. In the present embodiment, the vehicle is used to increase the determination accuracy. The determination using the indoor camera 90E and the determination using the rotation angle sensor 90G are used in combination. If the determination at step 410 is negative, the process returns.

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

  If the determination in step 412 is affirmative, the motor 22 is reversely rotated in step 414 and the process is returned. This is because when the occupant 12 is not conscious, the webbing 30 is loosened by rotating the motor 22 in the reverse direction to facilitate the rescue of the occupant 12.

  As described above, according to the present embodiment, after a vehicle collision, when there is a possibility of a vehicle collision, by rotating the motor 22 in the normal direction, the webbing 30 is reliably wound 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 a vehicle collision and the door of the vehicle is opened, the occupant is rotated by rotating the motor 22 in the reverse direction to loosen the webbing 30. Make 12 rescues easy.

DESCRIPTION OF SYMBOLS 10 Vehicle occupant restraint device 12 Crew 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 vehicle-mounted camera 90E vehicle interior 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 the seat belt by rotating the motor;
A group of sensors capable of detecting a vehicle collision and a vehicle collision;
A drive circuit for generating a voltage for rotating the motor;
A control unit that controls the drive circuit to generate a voltage for rotating the motor when there is a possibility of a secondary vehicle collision after a vehicle collision based on the detection result of the sensor group;
An occupant restraint device for a vehicle. A consciousness detection unit for detecting the presence or absence of occupant consciousness,
An opening detection unit for detecting that the vehicle door is opened;
With
The motor retractor is capable of withdrawing the seat belt by rotation of the motor in a direction opposite to that at the time of winding the seat belt,
The drive circuit generates a voltage for rotating the motor in the reverse direction;
When the control unit determines that the occupant is not conscious based on the detection result of the consciousness detection unit after a vehicle collision, and when the opening detection unit detects that the vehicle door is opened, The vehicle occupant restraint device according to claim 1, wherein control is performed to cause 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 the output shaft of the motor,
When the controller generates a voltage for rotating the motor so that the seat belt is wound and pulled out, the rotation angle of the output shaft detected by the rotation angle detector is linear. The vehicle occupant restraint device according to claim 2, wherein the occupant restraint is determined to be unconscious when the vehicle changes. The consciousness detection unit includes a vehicle interior camera that acquires image data of the occupant's face,
The vehicle occupant restraint apparatus according to claim 2, wherein the control unit determines whether or not the occupant is aware based on image data acquired by the vehicle interior camera.

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