JP6627691B2 - 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 the occupant, but as an example, when a vehicle collision is predicted, after removing the slack of the webbing by winding up the webbing with a motor, the explosive was used at the time of the vehicle collision. There is known a method in which a pretensioner is operated to restrain the occupant's body to a seat.

  However, the explosive pretensioner has the drawback that the cost increases and that once activated, it cannot be reused. Therefore, Patent Literature 1 discloses an invention of a seat belt retractor in which a webbing is wound by a motor not only when a vehicle collision is predicted but also at the time of a vehicle collision.

JP 2006-327413 A

  However, in the invention of the seat belt retractor disclosed in Patent Literature 1, no particular description is given regarding the power supply of the motor. The power supply of the seatbelt retractor of the cited document 1 is considered to be a vehicle-mounted battery with a nominal voltage of 12 V. However, such a power supply has a limitation in the driving force of a motor, and webbing is performed at a speed as high as an explosive pretensioner at the time of a vehicle collision. There was a problem that winding was difficult.

  An object of the present invention is to provide a vehicle occupant restraint device that winds up a webbing (seat belt) at a high speed at the time of a vehicle collision in consideration of the above fact.

Vehicle occupant restraint system according to claim 1 held so as not to consume the seat belt retractor capable of winding a seat belt by the supplied driving force, the driving force e accumulating with storing the driving force of the motor it and capable driving force holding unit, and fear and capable of detecting sensors a vehicle collision of a vehicle collision, on the basis of the sensor group detection results, the drive the motor with driving when there is a risk of a vehicle collision A control unit that controls the force holding unit to store and hold the driving force of the motor, and that controls the supply of the driving force stored in the driving force holding unit to the seat belt retractor in the event of a vehicle collision. .

  The vehicle occupant restraint device according to claim 1, further comprising a driving force holding unit capable of holding a driving force of the motor, wherein the control unit is configured to disturb the vehicle near the vehicle by a sensor group capable of detecting a vehicle collision and a vehicle collision. When it is determined that there is a risk of vehicle collision due to the presence of an object, the motor is driven, and the driving force holding unit holds the driving force of the motor.

  Further, the control unit performs control for supplying the driving force stored in the driving force holding unit to the seat belt retractor at the time of a vehicle collision.

  In this way, by supplying the driving force stored in the driving force holding unit to the seat belt retractor at the time of a vehicle collision, the seat belt can be wound up.

According to a second aspect of the present invention, in the vehicle occupant restraint apparatus according to the first aspect, the control unit controls the driving force holding unit to store and hold the driving force of the motor. When the possibility of collision further increases, control is performed to supply the driving force of the motor to the seat belt retractor, and the slack of the seat belt is removed.

  The vehicle occupant restraint device according to claim 2 removes the slack of the seatbelt by the driving force of the motor immediately before the vehicle collision, so that the seatbelt is driven by the driving force stored in the driving force holding unit at the time of the vehicle collision. When winding, the occupant's body can be reliably restrained to the seat.

  According to a third aspect of the present invention, in the vehicle occupant restraint device according to the first or second aspect, the driving force holding unit holds a driving force of the motor by a flywheel.

  In the vehicle occupant restraint device according to the third aspect, the driving force of the motor is stored as kinetic energy for rotating the flywheel, and the seat belt can be wound up using the kinetic energy stored in the flywheel at the time of a vehicle collision. become.

  According to a fourth aspect of the present invention, in the vehicle occupant restraint device according to the first or second aspect, the driving force holding unit holds the driving force of the motor by a spiral spring.

  In the vehicle occupant restraint device according to the fourth aspect, the driving force of the motor is stored as elastic energy of the spiral spring, and the seat belt can be wound up using the elastic energy stored in the spiral spring at the time of a vehicle collision. .

  According to the vehicle occupant restraint device of the first aspect, by supplying the driving force stored in the driving force holding unit to the seat belt retractor at the time of a vehicle collision, it becomes possible to wind up the seat belt at a high speed. This has the effect.

  According to the vehicle occupant restraint system of the second aspect, the slack of the seat belt is removed by the driving force of the motor immediately before the vehicle collision, whereby the occupant's body is securely restrained to the seat at the time of the vehicle collision. To play.

  According to the vehicle occupant restraint device of the third aspect, it is possible to wind the seat belt at a high speed using the kinetic energy stored in the flywheel at the time of both collisions.

  According to the vehicle occupant restraint device of the fourth aspect, there is an effect that it becomes possible to wind up the seat belt at high speed by using the elastic energy stored in the spiral spring at the time of a vehicle collision.

1 is a block diagram illustrating a schematic configuration of a vehicle occupant restraint device according to a first embodiment of the present invention. It is a block diagram showing an example of a circuit of a vehicle occupant restraint system concerning a 1st embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an example of a configuration of a driving force holding mechanism of the vehicle occupant restraint device according to the first embodiment of the present 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 first embodiment of the present invention. It is the schematic which showed an example of the structure of the driving force holding mechanism of the vehicle occupant restraint apparatus which concerns on the 2nd Embodiment of this invention.

[First Embodiment]
Hereinafter, a vehicle occupant restraint system 10 according to a first 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 an occupant with a seat belt (webbing).

  The vehicle occupant restraint system 10 includes a seat belt retractor 20, a webbing 30, a seat belt retractor control circuit 40, a seat belt retractor drive circuit 50, a vehicle-mounted battery (secondary battery) 80, and a vehicle ECU (Electronic Control Unit) 82. .

  As shown in FIG. 1, one end 30A of the webbing 30 is connected to a seat 14 or a lower anchor 32 fixed to the floor of the passenger compartment. 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 seat belt tongue plate 36 is provided between the shoulder anchor 34 and the lower anchor 32 of the webbing 30. The seat belt tongue plate 36 is detachable from a seat belt 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 seat belt tongue plate 36 is provided. Is engaged with the seat belt buckle 38 so that the webbing 30 holds 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 (not shown) for detecting a vehicle collision is connected to vehicle ECU 82, and when the possibility of a vehicle collision is detected by the sensor group and the automatic brake of the vehicle is operated, the seat is set. The motor of the belt retractor 20 is driven to remove the slack of the webbing 30. Further, at the time of a vehicle collision (when a vehicle collision is detected), the webbing 30 is rapidly wound by the driving force held by the driving force holding mechanism described later.

  The sensor group connected to the vehicle ECU 82 includes, for example, sensors such as a millimeter wave radar, a laser radar, a stereo camera, and an acceleration sensor. In the present embodiment, the sensor group includes at least one of a millimeter wave radar, a laser radar, and a stereo camera, and an acceleration sensor.

  Millimeter wave radar is a forward millimeter wave radar that detects the distance to the obstacle in front, a front side millimeter wave radar that detects the distance to the front side obstacle, and a rear millimeter wave that detects the distance to the rear obstacle 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 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.

  A laser radar is a device that irradiates a laser beam having a shorter wavelength than a millimeter wave to the front of a vehicle to detect an obstacle, and can relatively easily detect a nonmetallic object that is difficult to detect with a 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 stereo camera is provided, for example, in the vehicle interior near the center above the front windshield glass, photographs the front of the vehicle, detects peripheral obstacles, and measures the distance to the obstacles.

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

  The vehicle ECU 82 obtains the detection results of the millimeter-wave radar, the laser radar, and the stereo camera and performs collision prediction. Various known techniques can be applied to the collision prediction, and a detailed description thereof will be omitted.

  The seat belt retractor 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 including a switching element such as an FET (field effect transistor), as described later. I have. The switching elements constituting the H-bridge circuit of the seat belt retractor drive circuit 50 are controlled by the seat belt retractor control circuit 40.

  The seat belt retractor control circuit 40 is a so-called microcomputer, which controls the switching elements of the above-described seat belt retractor drive circuit 50 and drives the seat belt retractor 20 based on a command from the vehicle ECU 82 as described later. Control the force retention mechanism.

  FIG. 2 is a block diagram showing an example of a circuit of the vehicle occupant restraint device 10 according to the present embodiment. The seat belt retractor control circuit 40 controls the seat belt retractor drive circuit 50 based on a command from the vehicle ECU 82. The seat belt retractor 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 is connected to the drain (D) of the FET 52C. At the same time, the source of the FET 52B and the drain of the FET 52D are connected. The drains of the FETs 52A and 52B are connected to the positive electrode of a vehicle-mounted battery 80 via a backflow prevention diode 66, 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 seat belt retractor drive circuit 50 functions as a switch in which a current can flow between the drain and the source (ON state) when a positive charge voltage is applied to the gate (G). I do. In the present embodiment, when the motor 22 of the seat belt retractor 20 winds the webbing 30 around the spool 24, a positive charge control signal is output from the seat belt retractor control circuit 40 to each gate of the FET 52A and the FET 52D. Thereby, the FET 52A and the FET 52D are turned on, and the motor 22 is rotated forward. In the present embodiment, the main purpose is to rotate the motor 22 forward, but by turning on the FET 52B and the FET 52C, the motor 22 can be rotated in the reverse direction.

  When the motor 22 is rotated forward, one of the FETs 52A and 52D of the seat belt retractor drive circuit 50 is turned on and off intermittently to generate a pulse-like voltage and apply PWM (pulse width modulation) to the motor 22. )I do. 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 seat belt retractor control circuit 40 outputs a pulse-shaped control signal that repeats on and off intermittently to the FET 52A and the FET 52A. The output to one of the gates of the FET 52D causes the seat belt retractor drive circuit 50 to execute 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 seat belt retractor control circuit 40 calculates a motor current based on a 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 seat belt retractor control circuit 40 outputs a control signal for shortening the time during which one of the FET 52A and the FET 52D is turned on intermittently. I do. With such a control signal, the seat belt retractor drive circuit 50 reduces the pulse width of the voltage generated by the PWM to reduce the effective voltage value of the voltage applied to the motor 22, so that the motor current exceeds the rated current value. Can be prevented.

  The motor 22 is a brushed DC motor driven by a direct current. One end of a coil is connected to the source of the FET 52A and the drain of the FET 52C constituting the seat belt retractor drive circuit 50, and the other end of the coil is connected to the seat belt retractor. The source of the FET 52B and the drain of the FET 52D that constitute the drive circuit 50 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 via a driving force holding mechanism 90. When the motor 22 rotates forward, the webbing 30 is wound around the spool 24.

  In the present embodiment, the driving force holding mechanism 90 is a device that holds the driving force of the motor 22 by a flywheel. When there is a risk of a vehicle collision, the driving force of the motor 22 is held on the flywheel, and at the time of a vehicle collision, the driving force stored in the flywheel is released to rotate the spool 24 at high speed.

  As shown in FIG. 2, the driving force holding mechanism 90 transmits the driving force of the output shaft 92 to the flywheel while changing the driving force according to the rotation speed of the flywheel, and the transmission mechanism 94 performs a speed change. , A flywheel unit 98 containing a flywheel therein, and a gear train 100. Further, the driving force holding mechanism 90 includes a first electromagnetic clutch 102 for transmitting and interrupting a driving force between the transmission mechanism 94 and the flywheel unit 98, and a driving force between the flywheel unit 98 and the gear train 100. And a third electromagnetic clutch 106 for transmitting and interrupting a driving force between the transmission mechanism 94 and the gear train 100 on the output shaft 92.

  Each of the transmission mechanism control device 96, the first electromagnetic clutch 102, the second electromagnetic clutch 104, and the third electromagnetic clutch 106 is controlled by the seat belt retractor control circuit 40.

  FIG. 3 is a schematic diagram illustrating an example of the configuration of the driving force holding mechanism 90. The transmission mechanism 94 is, for example, a CVT (Continuously Variable Transmission), and includes a first pulley 94A provided on the output shaft 92 and a second pulley 94B provided on the flywheel rotating shaft 110, and the first pulley 94A A belt 94C is stretched between the first pulley 94B and the second pulley 94B. The first pulley 94A can be changed in diameter by a first actuator 96A, and the second pulley 94B can be changed in diameter by a second actuator 96B. The first actuator 96A and the second actuator 96B are seated through a transmission mechanism control device 96. It is controlled by the belt retractor control circuit 40.

  A rotation sensor 108 is provided near the end of the flywheel rotation shaft 110. The rotation sensor 108 is, for example, a magnetic sensor such as an MR sensor, and detects a magnetic field that changes according to the rotation of the flywheel rotation shaft 110 of the sensor magnet 108A provided at the end of the flywheel rotation shaft 110. The seat belt retractor control circuit 40 calculates the rotation speed of the flywheel rotation shaft 110 from a change in the magnetic field of the sensor magnet 108A detected by the rotation sensor 108.

  In the motor 22 driven by the electric power of the battery 80 of the present embodiment, since a strong driving force such as an explosive pretensioner is difficult, the driving force of the motor 22 is reduced before the vehicle collision by the flywheel in the flywheel unit 98. By storing the kinetic energy stored in the wheel 98A and releasing the kinetic energy stored in the flywheel 98A in the event of a vehicle collision, the spool 24 is rotated at a high speed to rapidly wind the webbing 30.

  Even when the kinetic energy is stored in the flywheel 98A, the driving force of the motor 22 is limited. Therefore, in the present embodiment, the driving force of the motor 22 is transmitted to the flywheel 98A via the transmission mechanism 94. For example, when the motor 22 starts rotating, the diameter of the first pulley 94A is minimized, the diameter of the second pulley 94B is maximized, and the gear ratio of the transmission mechanism 94 is minimized to reduce the load on the motor 22. As the rotation speed of the flywheel rotation shaft 110 detected by the rotation sensor 108 increases, the diameter of the first pulley 94A increases, the diameter of the second pulley 94B decreases, and the gear ratio of the transmission mechanism 94 increases. The flywheel 98A rotates at a high speed. The kinetic energy stored in the flywheel 98A increases as the rotation speed of the flywheel 98A increases, so that the flywheel 98A rotates at a high speed by the transmission mechanism 94 while reducing the load on the motor 22. I have.

  In this embodiment, the speed change mechanism 94 is a CVT capable of stepless speed change. However, a stepped speed change mechanism including a multi-stage sprocket and a chain, or a planetary gear mechanism may be used.

  Transmission and cutoff of the driving force are executed by controlling each of the first electromagnetic clutch 102, the third electromagnetic clutch 104, and the fourth electromagnetic clutch 106. Specifically, each of the first electromagnetic clutch 102, the second electromagnetic clutch 104, and the third electromagnetic clutch 106 is controlled as described below.

  To store kinetic energy in the flywheel 98A when there is a risk of a vehicle collision, the first electromagnetic clutch 102 is connected, and each of the second electromagnetic clutch 104 and the third electromagnetic clutch 106 is disconnected. As a result, the driving force of the motor 22 is transmitted to the flywheel 98A via the above-described transmission mechanism 94.

  When the danger of a vehicle collision is further increased and the automatic braking of the vehicle is activated, the third electromagnetic clutch 106 is connected to remove the slack of the webbing 30, and each of the first electromagnetic clutch 102 and the second electromagnetic clutch 104 is connected. Disconnect. As a result, the driving force of the motor 22 is transmitted to the spool 24.

  At the time of a vehicle collision, the second electromagnetic clutch 104 is connected, and each of the first electromagnetic clutch 102 and the third electromagnetic clutch 106 is disconnected. As a result, the kinetic energy stored in the flywheel 98A is transmitted to the spool 24 via the gear train 100, and winds the webbing 30 at high speed.

  Next, the operation of the present embodiment will be described. FIG. 4 is a flowchart illustrating an example of a process of the seat belt retractor control circuit 40 of the vehicle occupant restraint device 10 according to the present embodiment. In step 400, it is determined whether there is a possibility of a vehicle collision based on the detection result of the sensor group that detects the vehicle collision. The case where there is a possibility of a vehicle collision is, for example, a case where an object is detected within a predetermined distance from the vehicle by a millimeter wave radar or the like. In the case of an affirmative determination in step 400, the procedure proceeds to step 402, and in the case of a negative determination in step 400, detection of a fear of a vehicle collision by the sensor group is continued.

  In step 402, the driving force of the motor 22 is transmitted to the flywheel 98A to store kinetic energy in the flywheel 98A. Specifically, the seat belt retractor drive circuit 50 is controlled so as to supply the electric power of the battery 80 to the motor 22 of the seat belt retractor 20, and the transmission mechanism 94 and the first electromagnetic clutch 102 are controlled as described above. . To store sufficient kinetic energy in the flywheel 98A, it is desirable to rotate the motor 22 at high speed, but the motor may be overloaded. If the motor current detected by the current detection unit 70 may exceed the rated current value of the motor 22, the seat belt retractor control circuit 40 reduces the pulse width of the voltage generated in the seat belt retractor drive circuit 50 by PWM. Then, the effective voltage value of the voltage applied to the motor 22 is reduced.

  Further, the seat belt retractor control circuit 40 disconnects each of the second electromagnetic clutch 104 and the third electromagnetic clutch 106, connects the first electromagnetic clutch 102, and transmits the driving force of the motor 22 rotating to the flywheel 98A. At the same time, the kinetic energy is stored in the flywheel 98A by controlling the gear ratio of the transmission mechanism 94 according to the rotation speed of the flywheel rotation shaft 110 detected by the rotation sensor 108.

  In step 404, it is determined whether the possibility of a vehicle collision has further increased and the automatic braking of the vehicle has been activated. The case where the automatic braking of the vehicle is activated is a case immediately before the vehicle collision in which the sensor group detects that an obstacle exists within a shorter distance than the above-mentioned predetermined distance, depending on the vehicle. If an affirmative determination is made in step 404, the procedure proceeds to step 406. If a negative determination is made in step 404, the procedure returns to step 400, and the sensor group continues to detect the possibility of a vehicle collision.

  In step 406, the seat belt retractor drive circuit 50 is controlled so that the electric power of the battery 80 is supplied to the motor 22 of the seat belt retractor 20 to wind up the webbing 30. The seat belt retractor control circuit 40 outputs a PWM control signal to the seat belt retractor drive circuit 50 so that the seat belt retractor drive circuit 50 generates a voltage for rotating the motor 22 at an optimum rotation speed for removing the slack of the webbing 30. Output to the retractor drive circuit 50.

  Further, the seat belt retractor control circuit 40 disconnects each of the first electromagnetic clutch 102 and the second electromagnetic clutch 104, connects the third electromagnetic clutch 106, and transmits the driving force of the motor 22 to the spool 24.

  In step 408, it is determined whether the vehicle ECU 82 has detected the vehicle collision based on the detection result of the sensor group that detects the vehicle collision. If an affirmative determination is made in step 408, the kinetic energy of the flywheel 98A is released in step 410 to rotate the spool 24 at high speed. Specifically, each of the first electromagnetic clutch 102 and the third electromagnetic clutch 106 is disconnected, the second electromagnetic clutch 104 is connected, and the kinetic energy stored in the flywheel 98A is transferred to the spool 24 via the gear train 100. To communicate.

  After releasing the kinetic energy of the flywheel 98A in step 410, the process ends.

  In the case of a negative determination in step 408, for example, when the vehicle collision is not detected and the sensor group does not detect any obstacle, the winding of the webbing 30 is stopped in step 412. After stopping the winding of the webbing 30 in step 412, the procedure returns to step 400, and the detection of the possibility of a vehicle collision by the sensor group is continued.

  As described above, according to the present embodiment, when it is determined that there is a possibility of a vehicle collision, the motor 22 is driven, the driving force of the motor 22 is stored in the flywheel 98A, and the flywheel 98A is driven during the vehicle collision. By supplying the driving force stored in the seat belt retractor, the webbing 30 can be wound up at a speed as high as an explosive pretensioner.

  Further, in the present embodiment, the slack of the webbing 30 is removed by the driving force of the motor 22 immediately before the vehicle collision, so that when the webbing 30 is wound up by the driving force stored in the flywheel 98A at the time of the vehicle collision, the occupant cannot take up the vehicle. The body can be reliably restrained on the seat 14.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, although the driving force holding mechanism 190 is different from the driving force holding mechanism 90 of the first embodiment, the other configuration is the same as that of the first embodiment. Detailed description is omitted.

  In the first embodiment, the driving force of the motor 22 is stored as kinetic energy for rotating the flywheel 98A. However, in the present embodiment, the driving force of the motor 22 is stored as elastic energy in a spiral spring, a so-called mainspring.

  As shown in FIG. 5, the driving force holding mechanism 190 of the present embodiment includes a first gear train 192 for transmitting the driving force of the output shaft 92 to the spiral spring 200, a case 198 containing the spiral spring 200 therein, and A second gear train 202 is included. One end 200A of the spiral spring 200 is fixed to the spiral spring rotation shaft 210, and the other end 200B of the spiral spring 200 is fixed to the inner wall of the case 198.

  In addition, the driving force holding mechanism 190 includes a first electromagnetic clutch 204 that transmits and cuts off a driving force between the first gear train 192 and the spiral spring 200, and a driving force holding mechanism 190 between the spiral spring 200 and the second gear train 202. A second electromagnetic clutch 206 for transmitting and interrupting the driving force, and a third electromagnetic clutch 208 for transmitting and interrupting the driving force between the first gear train 192 and the second gear train 202 on the output shaft 92. Contains.

  Each of the first electromagnetic clutch 204, the second electromagnetic clutch 206, and the third electromagnetic clutch 208 is controlled by the seat belt retractor control circuit 40.

  In the present embodiment, when the output shaft 92 rotates in the direction of arrow A by the motor 22, the spiral spring rotation shaft 210 rotates in the direction of arrow B by the first gear train 192, and stores elastic energy in the spiral spring 200. . A braking mechanism 214 using an electromagnetic brake or the like is provided between the first electromagnetic clutch 204 and the second electromagnetic clutch 206 of the spiral spring rotation shaft 210. As described later, in the present embodiment, after the elastic energy is stored in the spiral spring 200, the first electromagnetic clutch 204 and the second electromagnetic clutch 206 are disconnected to remove the slack of the webbing 30 with the motor 22. In such a case, if the spiral spring rotating shaft 210 is not braked by the braking mechanism 214, the elastic energy stored in the spiral spring 200 is released unexpectedly. The braking mechanism 214 is controlled by the seat belt retractor control circuit 40.

  In the present embodiment, when there is a risk of a vehicle collision, elastic energy is stored in the spiral spring 200. In such a case, the first electromagnetic clutch 204 is connected, and each of the second electromagnetic clutch 206 and the third electromagnetic clutch 208 is disconnected. As a result, the driving force of the motor 22 is transmitted to the spiral spring 200 via the first gear train 192 described above.

  When the danger of a vehicle collision further increases and the automatic braking of the vehicle is activated, the third electromagnetic clutch 208 is connected to remove the slack of the webbing 30, and each of the first electromagnetic clutch 204 and the second electromagnetic clutch 206 is connected. Disconnect. As a result, the driving force of the motor 22 is transmitted to the spool 24. At the same time, the braking mechanism 214 is turned on to prevent the elastic energy stored in the spiral spring 200 from being released.

  At the time of a vehicle collision, the second electromagnetic clutch 206 is connected, the braking mechanism 214 is turned off, and each of the first electromagnetic clutch 204 and the third electromagnetic clutch 208 is disconnected. As a result, the spiral spring rotation shaft 210 rotates in the direction of arrow C due to the elastic energy stored in the spiral spring 200, and the rotation is transmitted to the output shaft 92 via the second gear train 202, and the output shaft 92 is moved in the direction of arrow D. Rotate in the direction. Then, the spool 24 takes up the webbing 30 at a high speed by the rotation of the output shaft 92.

  As described above, according to the present embodiment, when it is determined that there is a possibility of a vehicle collision, the motor 22 is driven, the driving force of the motor 22 is stored in the spiral spring 200, and the spiral spring 200 By supplying the driving force stored in the seat belt retractor 20, the webbing 30 can be wound up at a speed as high as that of an explosive pretensioner.

  Further, in the present embodiment, the slack of the webbing 30 is removed by the driving force of the motor 22 immediately before the vehicle collision, so that when the webbing 30 is wound up by the driving force stored in the spiral spring 200 at the time of the vehicle collision, the occupant 12 Can be securely restrained to the seat 14.

Reference Signs List 10 vehicle occupant restraint device 12 occupant 14 seat 20 seat belt retractor 22 motor 24 spool 30 webbing 40 seat belt retractor control circuit (control unit)
50 seat belt retractor drive circuit 80 battery 82 vehicle ECU (control unit)
90 Driving force holding mechanism (Driving force holding unit)
98 Flywheel unit (driving force holding unit)
98A flywheel (driving force holding part)
190 Driving force holding mechanism (Driving force holding unit)
200 Spiral spring (drive force holding part)

Claims (4)

A seat belt retractor that can wind up the seat belt by the supplied driving force,
A driving force holding unit that can store the driving force of the motor and hold the stored driving force so as not to consume the driving force ;
A sensor group capable of detecting a vehicle collision and a vehicle collision,
Based on the detection result of the sensor group, when there is a possibility of a vehicle collision, control is performed to drive the motor and to store and hold the driving force of the motor in the driving force holding unit, and to maintain the driving force at the time of a vehicle collision. A control unit that controls supply of the driving force stored in the unit to the seat belt retractor;
An occupant restraint system for a vehicle, including: The control unit controls the driving force holding unit to store and hold the driving force of the motor, and then supplies the driving force of the motor to the seat belt retractor when the risk of a vehicle collision further increases. The vehicle occupant restraint device according to claim 1, wherein the control is performed to remove the slack of the seat belt.   The vehicle occupant restraint device according to claim 1, wherein the driving force holding unit holds a driving force of the motor by a flywheel. The vehicle occupant restraint device according to claim 1, wherein the driving force holding unit holds the driving force of the motor by a spiral spring.