JP2009102012A - Seat belt device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt device for retracting and drawing a seat belt by a motor which is capable of rapidly retracting the seat belt while avoiding the start of the motor from a highly loaded state. <P>SOLUTION: When it is discriminated that a collision is inevitable, a motor (110) is driven for a while in the drawing direction of a seat belt (302) to loosen the seat belt. Thereafter, the motor (110) is driven in the retracting direction of the seat belt (302) to perform retraction at the high-speed rotation. At the same time, a locking mechanism (102) of the seat belt for locking the drawing of the retraction belt is also operated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a seat belt device that secures an occupant by restraining the occupant to a seat with a seat belt in the event of a vehicle collision, and in particular, a seat belt in which the tension of the seat belt is variable by a power source such as an electric motor. Relates to the device.

  2. Description of the Related Art Conventionally, there has been proposed a vehicle seat belt device that predicts a vehicle collision, winds up a seat belt with an electric motor before the collision, and restrains an occupant at the time of the collision. In a seat belt retractor using an electric motor, it is important to determine how much of the seat belt can be wound and how fast the seat belt can be wound. This is because the degree of slack that can be removed from the seat belt and the time that can be taken for collision prediction are determined.

  For example, in the “vehicle occupant protection system” proposed in Japanese Patent Laid-Open No. 9-132113, when there is no danger of a collision, the vehicle is in the comfort mode. In this state, the belt is wound around with the electric motor, and when the belt tension is changed from 2 kg to 3 kg, the motor is stopped, and after a certain period of time, the electric motor is gradually rotated in the drawing direction, and the belt tension becomes 0 kg. This is sometimes obtained by stopping the electric motor. Therefore, the tension is 0 kg, the occupant has no feeling of pressure, and the seat belt is not slack. In this comfort mode, when signals indicating various dangers are generated, the electric motor is driven to wind up the seat belt, and the tension of the seat belt is increased to restrain the occupant to the seat.

JP-A-9-132113

  However, if the seat belt is to be wound from a state where there is no slack, a load that restrains the occupant is applied to the electric motor from the initial stage of the belt winding, and the belt is wound while the electric motor does not reach a sufficient rotational speed. Will do. For this reason, in order to ensure the seat belt winding amount required when a collision is unavoidable, a large force is required and an electric motor having a large rotational torque is required. This type of motor is large in shape, heavy and expensive. Further, when a small electric motor is used and a large torque is obtained by using a reduction gear, the reduction ratio must be increased, so that the winding speed is reduced accordingly.

  Therefore, an object of the present invention is to provide a seat belt device that can quickly wind up a seat belt using a relatively small motor.

  In order to achieve the above object, the seat belt device of the present invention comprises a reel that winds a seat belt that restrains an occupant to a seat, a motor that rotationally drives the reel, and when the seat belt is wound around the reel. Drive the motor for a while in the seat belt pull-out direction to loosen the seat belt, and then drive the motor in the seat belt retracting direction to reduce the load when starting the motor to retract the seat belt. And a control means for controlling so as to be performed at high speed.

  With this configuration, the motor load is substantially in the no-load state at the initial rising stage of operating the motor, and the motor rapidly increases in rotational speed after startup. When the seat belt that has slackened is wound up and the occupant begins to be restrained, the rotational speed is considerably high. If the occupant restraint starts at this high rotational speed, the belt is wound more quickly than the case where the occupant is restrained from the beginning, and as a result, the belt is wound immediately at a lower rotational speed. It becomes possible to restrain an occupant to a seat earlier.

  The seat belt device of the present invention includes a reel that winds a seat belt that restrains an occupant to a seat, seat belt wearing detection means that detects wearing of the seat belt, and a winding direction of the seat belt. Or a motor for rotating the seat belt in the pull-out direction; and a control means for controlling the rotational drive of the motor. When the seat belt is detected, the control means moves the motor to the seat belt. The sheet belt is driven in the winding direction until the slack is removed, and when the slack is removed, the seat belt is driven in the pull-out direction so that the seat belt is slackened in advance by the amount necessary for starting the low load of the motor.

  Preferably, the control means detects the removal of the slack of the seat belt when the tension of the seat belt becomes a predetermined value, and estimates the tension based on the value of the current supplied to the motor.

  Preferably, the control means is 20 mm to 40 mm as a slack necessary for the low load rising.

  The seat belt device according to the present invention includes a reel that winds a seat belt that restrains an occupant to a seat, and prohibits the withdrawal of the seat belt from the reel in response to a command signal, and also winds the seat belt around the reel. A forcible lock mechanism that allows the vehicle to take off, a collision prediction means that predicts a vehicle collision and outputs a collision unavoidable signal when the collision is unavoidable, and the reel in the seat belt winding direction or the seat belt A motor that rotationally drives in the pull-out direction; and a control unit that controls the motor in response to the collision unavoidable signal, and the control unit pulls the motor out of the seat belt when the collision unavoidable signal is output. Then, the motor is driven in the seat belt winding direction and the forced lock mechanism is also activated.

  The seat belt device of the present invention predicts a collision between a reel that winds a seat belt that restrains an occupant to a seat and a vehicle, and outputs a collision avoidance signal when there is a risk of collision but can be avoided. A collision prediction means; a motor that rotationally drives the reel in the seat belt winding direction or the seat belt withdrawal direction; and a control means that controls the motor in response to the collision prediction signal. When the collision avoidance signal is output, the means drives the motor in the seat belt winding direction until the seat belt tension reaches a predetermined tension corresponding to a state in which the seat belt is less slackened. After reaching, the motor is driven in the pull-out direction for a while so that the amount of looseness of the seat belt becomes a predetermined amount.

  The seat belt device according to the present invention includes a reel that winds a seat belt that restrains an occupant to a seat, and prohibits the withdrawal of the seat belt from the reel in response to a command signal, and also winds the seat belt around the reel. A forcible lock mechanism that allows the vehicle to take off, a collision prediction means that predicts a vehicle collision and outputs a collision unavoidable signal when the collision is unavoidable, and the reel in the seat belt winding direction or the seat belt A motor that rotationally drives in the pull-out direction; a slack amount detecting means that detects a slack amount of the seat belt; and a control means that controls the motor in response to the collision unavoidable signal. When the unavoidable signal is output, the slack amount of the seat belt is read, and when the slack amount is equal to or greater than a predetermined value, the motor is wound around the seat belt. And the forced locking mechanism is also activated.When the amount of slack is smaller than a predetermined value, the motor is temporarily driven in the seat belt withdrawing direction so that the amount of slack is a predetermined value. The motor is driven in the seat belt winding direction and the forced lock mechanism is also activated.

  Preferably, the slack detection means detects the amount of withdrawal of the seat belt by a rotation sensor capable of detecting the rotation speed and the rotation direction of the rotation shaft of the reel around which the seat belt is wound, and the seat belt becomes a predetermined tension. The amount pulled out from the starting tension is detected as the slack amount.

  Further, as an equivalent means for giving slack to the seat belt before the electric motor is started, a mechanism for giving slack to the seat belt may be provided in a mechanism for pulling the buckle or a mechanism for drawing the lap belt fixing portion.

  In the seat belt device of the present invention, when starting the motor, the seat belt is slackened to the extent necessary for the motor speed to rapidly increase, and the seat belt winding is started from the low load state of the motor. The seat belt is wound up at high speed, and it is possible to quickly restrain the passenger on the seat. If the slack of the seat belt can be removed in a short time, it is possible to increase the time allocated to the collision determination, which is good.

FIG. 1 is an explanatory diagram illustrating the configuration of the seat belt device. FIG. 2 is an explanatory view illustrating a configuration example of the electric belt winding device. FIG. 3 is an explanatory view illustrating a configuration example of another electric belt winding device. FIG. 4 is a functional block diagram illustrating the configuration of the control unit 200. FIG. 5 is an explanatory diagram for explaining the potentiometer 111. FIG. 6 is a circuit diagram showing a configuration example of a motor drive circuit. FIG. 7 is a flowchart for explaining a first control mode (slack addition) of the control unit. FIG. 8 is a flowchart for explaining a first control mode (belt winding) of the control unit. FIG. 9 is a flowchart for explaining the control for maintaining the slack amount d1 of the control unit. FIG. 10 is a flowchart for explaining a second control mode (slack application / belt winding) of the control unit. FIG. 11 is a flowchart for explaining a third control mode (slack application / belt winding corresponding to three states) of the control unit. FIG. 12 is a perspective view showing an example of a part of the seat belt retractor. FIG. 13 is a perspective view showing another example of the seat belt retractor. 14 is a cross-sectional view of the ratchet wheel 18 of the locking mechanism shown in FIG. 13 in the rotation axis direction. FIG. 15 is an explanatory diagram for explaining the operation of the lock mechanism due to a sudden withdrawal of the seat belt (seat belt acceleration). FIG. 16 is an explanatory diagram for explaining the lock arm 26. FIG. 17 is an explanatory diagram for explaining the inertia plate 30. FIG. 18 is an explanatory view for explaining the operation of the lock mechanism by the seat belt acceleration. FIG. 19 is an explanatory diagram for explaining the operation of the lock mechanism by the seat belt acceleration. FIG. 20 is an explanatory diagram for explaining the operation of the lock mechanism by the seat belt acceleration. FIG. 21 is an explanatory diagram for explaining the operation (non-locked state) of the electromagnetic actuator. FIG. 22 is an explanatory diagram for explaining the operation (locked state) of the electromagnetic actuator. FIG. 23 is an explanatory diagram illustrating an example of another electromagnetic actuator.

Embodiments of the present invention will be described below with reference to the drawings.
First, the point of interest of the present invention will be described. In the initial stage of operating the electric motor, if the load of the electric motor is set to a substantially no-load state for a certain time, the electric motor rapidly increases in rotational speed after startup. If winding is started from a state where the seat belt is slackened by a predetermined amount, the rotation speed is increased to a considerable rotational speed at the time when the seat belt is wound and the occupant starts restraining. Compared to the case where the electric motor is started with a high load that restrains the occupant from the beginning, the belt is wound up more quickly. When the same electric motor and the same power source are used, the maximum amount of seat belt retracted by the electric motor when the restriction start point is used as a reference is greater when the restriction starts when the electric motor reaches a certain speed. . However, in order to obtain a high initial speed of the electric motor, the seat belt is loosened to secure a no-load section (period), and accordingly, the restraint start time at which restraint of the occupant starts is delayed. Therefore, by setting the amount of seat belt slack to the necessary limit, it is possible to complete occupant restraint that is faster than before. The slack amount of the seat belt is preferably an amount that the electric motor can reach the maximum speed (the amount of rotation that has been rotated until the maximum rotation speed is reached), but if the time to reach the maximum speed is taken into consideration The amount of slack is preferably about 60% or more of the maximum speed.

  FIG. 1 shows a seat belt device. The seat belt device is disposed at the waist by inserting an electric winding device 100 that winds up the seat belt 302 that restrains the occupant to the seat 301, a through anchor 303 that folds the seat belt 302 in the vicinity of the shoulder of the occupant, and a seat belt. The tongue plate 305 that engages with the buckle 304, the anchor 306 that fixes the end of the seat belt 302 to the vehicle body, the switch 307 built in the buckle, the control unit 200 that controls the motor of the belt winding device 100, and the collision of the vehicle It is comprised by the collision prediction part 401 grade | etc., To predict.

  FIG. 2 is an explanatory diagram schematically illustrating the configuration of the electric winding device 100. In the figure, an electric winding device 100 includes a frame 101. The frame 101 is provided with a reel 103 for winding a seat belt (not shown) and a reel shaft 103a that is coupled to the reel 103 and serves as a central axis of reel rotation. Fixed to the right end of the reel shaft 103a is a later-described seat belt locking mechanism 102 that locks the withdrawal of the seat belt when a predetermined deceleration acts on the vehicle or when the seat belt is pulled out at a predetermined acceleration. Yes. The lock mechanism 102 is further provided with an electromagnetic actuator 112 described later for forcibly operating the lock mechanism 102. The operation of the electromagnetic actuator 112 is controlled by the output of the control unit 200 described later. The seat belt lock mechanism 102 is configured such that the seat belt can be wound by the electric motor 110 even when the seat belt drawer is locked.

  A rotation sensor 113, a pretensioner 104, a pulley 105, and a potentiometer 111 are provided at the left end of the reel shaft 103a.

  The rotation sensor 113 includes a magnet 113b in which a large number of NS magnetic poles are alternately arranged so as to go around the side wall of the reel 103, and two magnetic sensors 113a attached to the retractor base 101. The two magnetic sensors are attached with a half-cycle shift, and detect the number of rotations and the direction of rotation of the reel. The output of the magnetic sensor 113a is supplied to the control unit 200.

  The pretensioner 104 is operated by the output of a collision detector (not shown), rotates the reel shaft 103a in the seat belt winding direction, forcibly winds the seat belt, and restrains the occupant to the seat. The pretensioner 104 is, for example, an explosive pretensioner, and includes a gas generator, a cylinder that seals gas generated from the gas generator, a piston that moves in the cylinder by gas pressure, and movement of the piston via a clutch mechanism. And a transmission mechanism for converting the rotational movement of the reel shaft 103a.

  The pulley 105 fixed to the reel shaft 103 a is connected to the pulley 106 fixed to the shaft of the DC motor 110 via a power transmission belt 107. A predetermined number of external teeth are formed on the outer circumferences of the pulleys 105 and 106, and a predetermined number of internal teeth are also formed on the inner circumference of the belt 107. The teeth of the pulley 105 for the reel shaft, the pulley 106 for the motor, and the belt 107 mesh with each other without excess and deficiency, and the rotation of the motor 110 is transmitted to the reel shaft 103a. The motor 110 is fixed to the frame 101 at at least two points, and operates according to the output of the control unit 200.

  As shown in FIG. 5, the potentiometer 111 provided at the leftmost end of the reel shaft 103a includes a resistor to which a voltage is applied to both ends and a slider that is interlocked with the rotation of the reel shaft 103a. Then, a voltage value corresponding to the rotation amount from the reel shaft 103a reference position is output to the control unit 200.

  In the above-described example, the rotation sensor 113 and the potentiometer 111 are provided as examples of slack detection, but only one of them may be provided.

  FIG. 3 is an explanatory diagram schematically illustrating another configuration of the electric winding device 100. In the figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In this example, a take-up spring 114 that urges the reel 103 in the take-up direction is provided on the reel shaft 103a. The winding spring is, for example, a string winding spring that is spirally wound around the reel shaft 103a. When the seat belt is pulled out, a weak tension in the winding direction is applied to the seat belt.

  FIG. 4 is a functional block diagram illustrating a schematic configuration of the control unit 200. As shown in the figure, the control unit 200 is configured by a microcomputer system. The CPU 201 controls the operation of an electromagnetic actuator (for example, a solenoid) 112 that loads the control program and data stored in the ROM 202 to the work area of the RAM 203 and forcibly operates the motor 110 and the seat belt lock mechanism 102.

  The above-described collision prediction unit 401 determines whether there is a possibility that a collision between the host vehicle and an obstacle such as a preceding vehicle may occur, or whether or not the collision can be avoided. For example, the distance between the vehicle and the obstacle is measured every predetermined time by a non-contact type distance sensor such as a laser radar or an ultrasonic sensor. The relative velocity is calculated from the change over time of this distance. Divide the distance by the relative velocity to calculate the time to collision. If the collision time is a predetermined time T2 or more and T1 or less (provided that T1> T2), it is determined that there is a possibility of collision and the collision avoidance operation is possible, and the first signal (collision) (Avoidable signal) is output. If the time until the collision is smaller than T2, it is determined that the collision avoidance operation is impossible, and the second signal (collision unavoidable) is output. These signals are supplied to the input interface 204, and the “collision unavoidable flag” and “collision unavoidable flag” in the flag area (flag register) of the RAM 203 are set to ON. This causes the CPU 201 to start interrupt processing.

  The output of the buckle switch 307 sets a flag corresponding to the presence or absence of the belt in the flag area of the RAM 203 via the input interface 204.

  The output voltage of the potentiometer 111 is A / D converted at a predetermined cycle by the input interface 204. The input interface 204 has a built-in CPU and monitors the converted output voltage data. For example, the rotation state of the shaft 103a is determined by the difference between the previous value and the current value of the output voltage data, and the “drawing” of the seat belt is determined depending on whether the difference between the previous value and the current value of the output voltage data is positive or negative. "Flag" or "winding" flag is set in the flag area of the RAM 203. Further, the output voltage data is written in the rotation amount area of the RAM 203 by the DMA operation. The amount of change in the pulling direction from the output voltage data when the belt is wound corresponds to the amount of slackness of the belt. This slack amount is written in the belt slack amount area 1 provided in the RAM 203.

  The waveform output corresponding to the amount of rotation of the reel 103 of the rotation sensor 113 is amplified, shaped by the input interface 204, and supplied to the up / down counter. The amount of change in the pull-out direction from the count value when the belt is wound corresponds to the amount of slackness of the belt. The belt slack amount is written in a belt slack amount area 2 provided in the RAM 203. As described above, in order to detect the slack of the belt, either the potentiometer 111 or the rotation sensor 113 may be used.

  When a predetermined condition set in the control program is satisfied, the CPU 201 gives a forward rotation command, a reverse rotation command, and a drive stop command for the motor 110 to the output interface 205. The output interface 205 generates gate signals G 1 and G 2 corresponding to these commands and supplies them to the motor drive circuit 206. For forward rotation commands, G1 and G2 are set to “H” and “L”, respectively. For reverse rotation commands, G1 and G2 are set to “L” and “H”, respectively, and to drive stop commands. , G1 and G2 are set to “L” and “L”, respectively.

  FIG. 6 is a circuit diagram showing a configuration example of a motor drive circuit. A transistor bridge circuit is formed by four transistors, PNP transistors Q1 and Q2, and NPN transistors Q3 and Q4. The emitters of the transistors Q1 and Q2 are connected to each other, and the power source Vc is supplied to the connection point. The emitters of the transistors Q3 and Q4 are also connected to each other, and a ground potential is supplied to the connection point.

  The emitter output currents of the transistors Q3 and Q4 are level-detected by the current detector CT, and a detection signal is sent to the output interface 205. The output interface 205 A / D converts the current value and writes the current value in the belt tension area of the RAM 203 by a DMA operation. Since the current value flowing through the motor is related to the torque, the seat belt tension F can be estimated from this.

  The collector of the transistor Q1 and the collector of the transistor Q3 are connected via a diode D1. The collector of the transistor Q2 and the collector of the transistor Q4 are connected via a diode D2. The base of the transistor Q1 and the collector of the transistor Q4 are connected via a bias resistor R1. The base of the transistor Q2 and the collector of the transistor Q3 are connected via a bias resistor R2. A DC electric motor M is connected between the collectors of the transistors Q1 and Q2.

  In such a configuration, when a normal rotation command signal (G1 = "H", G2 = "L") is supplied from the output interface 205 to the gates of the transistors Q3 and Q4, the transistor Q3 is turned on and the transistor Q4 is turned off. Become. The collector of the transistor Q3 is brought to the ground level by conduction, and the base of the transistor Q2 is biased to a low level (substantially ground level) via the resistor R2 to make the transistor Q2 conductive. The collector of the transistor Q4 is substantially at the power supply Vc level, biasing the base of the transistor Q2 to a high level via the resistor R1, and making the transistor Q1 non-conductive. As a result, a forward current path is formed by the path of the power source Vc, the transistor Q2, the motor M, the diode D1, the transistor Q3, and the ground, and the motor M rotates in the direction of winding the seat belt.

  When a reverse rotation command signal (G1 = "L", G2 = "H") is supplied from the output interface 205 to the gates of the transistors Q3 and Q4, the transistor Q3 is non-conductive and the transistor Q4 is conductive. The collector of the transistor Q4 is at the ground level, and the base of the transistor Q1 is biased to a low level via the resistor R1 to make the transistor Q1 conductive. The collector of the transistor Q3 is substantially at the power supply Vc level, biases the base of the transistor Q2 to a high level via the resistor R2, and makes the transistor Q2 non-conductive. As a result, a current path in the reverse direction is formed by the path of the power source Vc, the transistor Q1, the motor M, the diode D2, the transistor Q3, and the ground, and the motor M rotates in the direction of pulling out the seat belt.

  When a drive stop command signal (G1 = “L”, G2 = “L”) is supplied from the output interface 205 to the gates of the transistors Q3, Q4, the NPN transistors Q3, Q4 are both turned off. When the transistor Q3 is turned off from the conductive state, the collector of the transistor Q3 rises from the ground level to a substantially power supply level, biasing the base of the transistor Q2 to a high potential and also shutting off the transistor Q2. Similarly, when the transistor Q4 is turned off from the conducting state, the collector of the transistor Q4 rises from the ground level to a substantially power supply level, biasing the base of the transistor Q1 to a high potential and shutting off the transistor Q1. In this way, when a drive stop command is issued, each transistor constituting the bridge becomes non-conductive.

  Returning to FIG. 4, the CPU 201 gives a solenoid operation command to the output interface 205 when a condition for forcibly locking the seat belt pull-out described later is satisfied. The operation command set in the register flag of the output interface 205 is amplified by a power amplifier 207 from a logic level signal to a level at which the solenoid can be driven, and is given to the solenoid 112. When the solenoid operates, the actuator moves, and the lock mechanism 102 of the winding device 100 is operated.

  FIG. 7 is a flowchart for explaining a first control mode of the control unit 200. In this example, in a winding device of a type that does not incorporate a winding spring 114 as shown in FIG. 2, when a seat belt is worn, a predetermined amount of slack is taken into consideration when taking up the winding time required for occupant restraint in an emergency. Set in advance.

  The CPU 201 periodically monitors the seat belt wearing flag by executing the main program (S22). When the previous wearing flag is off and the current wearing flag is on, that is, when the occupant pulls out the seat belt and attaches the seat belt (S22; YES), the motor 110 is moved in the seat belt winding direction. Drive (S24). The CPU 201 monitors the value of the belt tension F grasped by the current value of the motor (S26; NO). When the tension F reaches a predetermined tension F1 in which the seat belt restraining the occupant is free of slack (S26; YES), the motor 110 is stopped and driven in the direction in which the seat belt is pulled out, and the predetermined slack is obtained. The quantity d1 is given. For example, the motor 110 is driven for a predetermined time corresponding to the withdrawal of the seat belt from 20 mm to 30 mm (S28). If there is such a slack, the passenger will not feel uncomfortable with the belt. Moreover, it is an allowable range of time required for passenger restraint. If the slack is larger than this, the belt is loose and the passengers feel uneasy. In addition, when it is determined that a collision is unavoidable, even if the belt is wound by a motor, the slack is not sufficiently removed (not in time). If the slack is less than the above range, the belt may come into strong contact with the body and cause a sense of incongruity. After securing the slack amount d1, this routine is terminated.

  FIG. 8 is a flowchart illustrating a control mode in the event of a vehicle collision after the first control mode shown in FIG. 7 is executed.

  When the collision avoidance impossible flag is set in the seat belt wearing state (S32) (S34; YES), the CPU 201 drives the motor 110 in the belt winding direction. Since the slack amount d1 is secured in the seat belt, the load on the motor is small, the motor rotates at a high speed, and the belt is wound (S36). At the same time, the actuator 112 is operated to lock the seat belt lock mechanism 102 to prevent the seat belt from being pulled out (S38). As described above, the seat belt lock mechanism 102 prevents the belt from being pulled out, but does not prevent the belt from being wound. Thereafter, this routine is terminated. This routine is not performed in a state where the seat belt is not attached (S32; NO) or in a state where collision can be avoided (S34; NO).

  As described above, when a state where collision avoidance is impossible with a predetermined amount of slack in the seat belt secured, the motor can rotate at high speed in the belt winding direction. As a result, occupant restraint is performed in a state where the slack of the belt is removed (maximum winding amount), and occupant safety is achieved.

  FIG. 9 is a flowchart showing a control mode for maintaining the required amount of slack d1. The required amount of slack d1 of the seat belt is secured by the control shown in FIG. However, when the occupant moves greatly or the occupant pulls out the seat belt, the amount of slack is not maintained within the required range of d1, and the slack is not sufficiently removed in the winding of the seat belt in FIG. It is possible.

  Therefore, as shown in FIG. 9, the CPU 201 monitors the seatbelt wearing flag, and when the seatbelt is worn (S42; Yes), periodically reads the amount of withdrawal of the seatbelt (S44), It is determined whether the slack of the belt is within the range of the slack amount d1 (S46). If it is within the range of the slack amount d1 (S46; YES), the slack amount d1 is maintained (secured), so this routine ends. If it is not within the range of the slack amount d1 (S46; NO), the motor 110 is driven in the belt winding direction or the pulling direction in order to set the slack amount d1 of the seat belt (S48). Reading, comparing, and motor driving of the withdrawal amount are repeated (S44 to S48), and the slack of the seat belt is set to the slack amount d1. After setting, this routine is terminated.

  In this way, the required slack amount d1 of the seat belt can be kept constant.

  FIG. 10 is a flowchart for explaining a second control mode of the control unit 200. An example of this is in a winding device of a type incorporating a winding spring 114 as shown in FIG. 3, that is, a belt winding device of a type in which excess slack of the seat belt is removed by the weak tension of the winding spring 114. It is intended to shorten the winding time required for restraining passengers in an emergency. For this reason, the motor is driven in the belt pulling direction for a while to loosen the belt by a required slack amount d1, and then the motor is driven in the belt winding direction to start winding the belt.

  In FIG. 10, when the seat belt is worn (S52; YES), the CPU 201 determines whether or not the collision avoidance flag is periodically set (S54). If the collision avoidance impossible flag is not set (S54; NO), this routine ends. When the collision avoidance impossible flag is set (S54; YES), the motor 110 is temporarily driven in the seat belt withdrawing direction for a while to give the required slack amount d1 (S56). Thereafter, the motor 110 is driven in the seat belt winding direction (S58). At the same time, the actuator 112 is operated to force the seat belt lock mechanism 102 into the locked state. Even in the locked state, the belt can be wound (S60). As a result, the seat belt can be wound up to the maximum extent and the occupant is restrained by the seat.

  When the seat belt is not attached (S52; NO), the CPU 201 releases the lock of the seat belt lock mechanism (S62) and stops the winding drive of the motor 110 (S64). When the driving of the motor 110 is stopped, the seat belt is stored in the winding device 100 by winding by the winding spring 114.

  FIG. 11 is a flowchart for explaining a third control mode of the control unit 200. This example is a winding device of a type incorporating a winding spring 114 as shown in FIG. 3, that is, a belt winding device of a type that removes excessive slack of the seat belt by a weak tension of the winding spring 114. It is intended to shorten the winding time required for restraining passengers in an emergency. Therefore, the current amount of seat belt slack is discriminated, and depending on the result, it is selected whether the belt is immediately wound or whether the belt is wound once the belt is slackened by a predetermined amount.

  In FIG. 11, the CPU 201 periodically monitors the “collision unavoidable flag” and the “collision unavoidable flag” when the seatbelt wearing flag is on (S72; YES). If the “collision unavoidable flag” is on (S74; YES) and the “collision unavoidable flag” is off (S76; NO), there is a possibility of collision, so the seat belt is wound (S78). The belt is wound up until the belt tension reaches the predetermined value F1 (S80). When the tension reaches the predetermined value F1 (S80; YES), the seat belt is driven to the drawer side. After a predetermined time, the motor 110 is stopped and the slack amount d1 is set in the seat belt. The motor 110 is supplied with a current that generates a force that maintains the belt slack d1 against the winding spring 114 (S82). Note that feedback control for maintaining the slack amount d1 as shown in FIG. 9 may be performed.

  By maintaining the required amount of slack, when a vehicle collision becomes inevitable, the winding of the belt can be started immediately from a state where the motor load is low.

  When the “collision unavoidable flag” is on (S74; YES) and the “collision unavoidable flag” is also on (S76; YES), the CPU 201 determines the current seat belt slack amount from the slack amount area of the RAM 203. It is determined whether the read and slack amount is greater than or equal to a predetermined value d1 (S84).

  When the slack is equal to or greater than the predetermined value d1 (S84; YES), the seat belt is immediately wound (S86), and at the same time, the seat belt lock mechanism is activated (S88). As a result, the motor rotates at high speed to wind the belt, and the occupant is restrained by the seat in a state where the belt is not slack.

  When the slack does not exceed the predetermined value d1 (S84; NO), the seat belt is once driven to the pull-out side to secure a predetermined slack amount d1 (S90). Thereafter, the seat belt is wound up (S86), and at the same time, the seat belt lock mechanism is operated (S88). As a result, the motor is prevented from starting from a high load state, and the belt is wound after the rotational speed is increased. Even a small motor can take up the belt quickly.

  If the seat belt is not attached (S72; NO), or if there is no possibility of collision (S74; NO), the seat belt drawer lock is released (S92), and the belt winding drive is also stopped. (S94). When the drive of the motor is stopped, the unmounted seat belt is stored in the winding device 100 by winding by the winding spring 114. When the seat belt is attached, the slack of the belt is removed by the weak tension by the winding spring 114.

  12 to 23 are exploded views for explaining the seat belt lock mechanism (reel mechanical lock mechanism, seat belt acceleration sensing means, vehicle deceleration sensing means) 120 and the electromagnetic actuator 112 of the winding unit 100. FIG. It is a perspective view and a principal part longitudinal cross-sectional view. In FIG. 12, the pretensioner is not attached. If necessary in terms of vehicle characteristics, a pretensioner is installed between the retractor base 1 and the power transmission unit 15 in FIG. 12, as shown in FIG.

  12 to 17, most of the retractor base 1 has a U-shaped cross section, and opposite side plates 1a and 1b are opposed to each other, and take-up shaft through holes are formed in the seat belt. A reel 3, which is a take-up shaft for winding 302 (not shown), is rotatably supported in a state of being inserted through the take-up shaft through holes.

  Engagement internal teeth 2 are formed on the inner peripheral edge of the winding shaft through-hole provided in the side plate 1a, and a ring member 4 is juxtaposed outside the winding shaft through-hole. The ring member 4 is drawn along the inner periphery, and when the ring member 4 is fixed to the outer surface of the side plate 1a by the rivet 40, the engagement inner teeth 2 and the inner periphery of the ring member 4 An axial gap is formed between the two.

  An emergency lock mechanism is provided on the side plate 1a side of the base 1 to prevent the seat belt from being pulled out in an emergency. Further, on the side plate 1b side of the base 1, a power transmission unit including a pulley 105, a potentiometer 111 and the like connected to a shaft 15c (corresponding to a reel shaft 103a) driven by an electric motor 110 via a timing belt 107 (not shown). 15 is arranged. The reel 3 is a substantially cylindrical winding shaft integrally formed of an aluminum alloy or the like, and penetrates in a diametrical direction so that the end of the seat belt is inserted and held in the body portion 28 around which the seat belt is wound. A slit opening 28a is provided. In addition, a flange member 13 formed separately is mounted on the outer peripheral portion of the reel 3 to prevent the seat belt from being disturbed. In addition, the seat belt wound around the outer periphery of the reel 3 assembled to the retractor base 1 is regulated in its entry / exit position by inserting a seat belt guide 41 attached to the upper portion of the retractor base 1 on the back plate side. .

  Rotating support shafts for rotatably supporting the reel 3 are projected on both end surfaces of the reel 3, but a separate support shaft pin 6 is used as a rotation support shaft on the sensor side end surface of the reel 3. It is press-fitted. Further, on the sensor side end surface of the reel 3, a support shaft 7 is provided so as to pivotally support a pole 16, which is a lock member that can be engaged with the engaging internal teeth 2 formed on the side plate 1 a, so as to be able to swing and rotate. ing. Further, when the pole 16 swings and rotates in a direction to engage with the engaging inner teeth 2, the pole rear end portion 16 e on the opposite side to the swinging side end portion of the pole 16 is positioned, When a large load is applied to the pole 16 in between, a pressure receiving surface 45 that receives the load is provided on the sensor side end surface of the reel 3.

  Further, on the sensor side end surface of the reel 3, a counterclockwise rotation of a swing lever member 20 pivotally supported by a ratchet wheel 18 which is a latch member of a lock actuating means described later is regulated. A locking projection 8 is provided. The recess 9 includes a tension coil spring 36 that rotates and biases the ratchet wheel 18 in the direction in which the seat belt is pulled out (in the direction of arrow X2 in FIG. 13), and an arm portion 26c of a lock arm 26 that presses a sensor spring 25 described later. It is escape to prevent it from interfering with.

  Engaging teeth 16c that can be engaged with the engaging inner teeth 2 formed on the side plate 1a are integrally formed at the swing end portion of the pole 16. Further, a shaft hole 16a that is loosely fitted to the support shaft 7 is provided in the center of the pole 16, and an engagement protrusion 16b positioned on the swing end side and a pole rear end are provided on the sensor side surface of the pole 16. A pressing protrusion 16d located on the side of the portion 16e is projected.

  That is, since the shaft hole 16a is loosely fitted to the support shaft 7, the pole 16 is supported by the support shaft 7 so as to be able to swing and rotate and to move relative to the support shaft 7 by a predetermined amount. Further, the end of the support shaft 7 passing through the shaft hole 16a of the pole 16 is crimped into the locking hole 17b of the holding plate 17 fitted through the through hole 17a by the support shaft pin 6 press-fitted into the reel 3. The holding plate 17 prevents the pole 16 from floating from the end face of the reel 3.

  The end of the engagement protrusion 16b of the pole 16 is inserted into a cam hole 18a formed in a ratchet wheel 18 that is disposed outside the holding plate 17 and is pivotally supported by the support shaft pin 6. Has been. Therefore, when the ratchet wheel 18 rotates relative to the reel 3 in the seat belt winding direction (the direction of the arrow X1 in FIG. 13), the cam hole 18a causes the end of the engagement protrusion 16b to move in the radial direction from the rotation center axis of the reel 3. Since it acts so as to move outward, the pole 16 is swung around the support shaft 7 in the direction of engagement with the engagement internal teeth 2 formed on the side plate 1a (in the direction of arrow Y1 in FIG. 12). .

  That is, the pole 16 is swung and rotated in the direction in which it engages with the engagement inner tooth 2, and the engagement tooth 16 c of the pole 16 engages with the engagement inner tooth 2, so Locking means for preventing rotation is configured. The ratchet wheel 18 is a ratchet wheel whose center hole is pivotally supported by the support pin 6, and ratchet teeth 18 b for engaging with the sensor arm 53 of the vehicle body acceleration sensing means 51 on the outer periphery thereof. Is formed. Further, the flange portion 6a of the spindle pin 6 has a center hole 30a of an inertia plate 30 which is a disc-like inertia member for constituting a seat belt acceleration sensing means which is an inertia sensing means for sensing the pull-out acceleration of the seat belt. It is pivotally supported. A locking claw 23 projecting toward the outside of the winding device at the periphery of the center hole of the ratchet wheel 18 engages with the engagement hole 30b to position the inertia plate 30 in the thrust direction. An engagement protrusion 31 of the inertia plate 30 is engaged with the elongated hole 24 formed in the ratchet wheel 18, and one end edge 24 a of the elongated hole 24 is in the rotational direction of the inertia plate 30 when the emergency lock mechanism is not activated. Positioning is performed (see FIG. 15).

  As shown in FIG. 15, a shaft portion 22 that pivotally supports the lock arm 26 and a spring hook portion 55 project from the outer surface of the ratchet wheel 18. As shown in FIG. 17, the inertia plate 30 is formed with an opening 56 through which the spring hook portion 55 is inserted. The opening 56 is formed in an elongated hole shape in which the inertia plate 30 can rotate relative to the ratchet wheel 18 in a state where the spring hook portion 55 is inserted, and a spring corresponding to the spring hook portion 55 is formed at one end thereof. A hook portion 57 is provided.

  A compression coil spring 58 is inserted between the pair of spring hook portions 55 and 57. In the compression coil spring 58, as shown in FIG. 18, the engagement protrusion 31 on the inertia plate 30 is in contact with the other end edge 24b of the elongated hole 24 formed in the ratchet wheel 18 (that is, non-rotating). It is energized so that it is kept in the locked state.

  On the inner side surface of the ratchet wheel 18, there is provided a spring latching portion 21 for latching the other end of the tension coil spring 36 whose one end is latched on the latching portion 17 c of the holding plate 17. 3, the ratchet wheel 18 is urged to rotate in the direction in which the seat belt is pulled out (the direction of the arrow X2). As shown in FIG. 16, both ends of the lock arm 26 are engaged with an engaging claw 26 b that can mesh with the internal gear 34 a of the gear case 34 and a pair of hook portions 18 d provided on the outer surface of the ratchet wheel 18. An arm portion 26c that presses the central portion in the longitudinal direction of the supported linear sensor spring 25 is provided.

  Therefore, the lock arm 26 constitutes a locking member that prevents the rotation of the ratchet wheel 18 in the seat belt withdrawing direction by engaging the engaging claw 26b with the internal gear 34a that is the engaged portion. The engaging claw 26 b is pressed and urged against the contact portion 32 of the inertia plate 30 by the urging force of the sensor spring 25. Note that an opening is formed in the ratchet wheel 18 corresponding to the swing range of the arm portion 26c, and the arm portion 26c passes through the opening. This is for ensuring the engagement state of the arm portion 26c with the sensor spring 25. Is.

  The contact portion 32 is a cam surface on which the back portion 26d of the engagement claw 26b of the lock arm 26 is slidably contacted, and a first cam surface 32a where the rotation of the inertia plate 30 does not affect the lock arm 26, and an inertia for the reel 3. A second cam surface 32b that swings the lock arm 26 so that the engagement claw 26b meshes with the internal gear 34a in accordance with the rotation delay of the plate 30 is provided.

  In the unlocked state of the emergency lock mechanism, the first cam surface 32a is in contact with the back portion 26d of the lock arm 26, and the back portion 26d is in the second state until the rotation delay of the inertia plate 30 with respect to the reel 3 exceeds a certain amount. The cam surface 32b is not contacted. The length of the first cam surface 32a (that is, the amount by which the inertia plate 30 rotates while the back portion 26d is in sliding contact with the first cam surface 32a) is the inertia acting on the inertia plate 30 when the entire amount of the seat belt is stored. Even if the inertia plate 30 causes a rotation delay with respect to the reel 3 due to the force, the first cam is not so large that the back portion 26d of the lock arm 26 does not reach the second cam surface 32b. The length of the surface 32a is set.

  Further, the lock arm 26 in the present embodiment is formed with a contact claw 26e at the swing end opposite to the engagement claw 26b. The inertia plate 30 is provided with a stepped portion 33 with which the contact claw 26e can be contacted so as to correspond to the contact claw 26e. When the inertia plate 30 is in the initial position in the unlocked state, the stepped portion 33 restricts the rotation of the lock arm 26 in the locking direction by the contact of the contact claw 26e. As shown in FIGS. 19 and 20, when the inertia plate 30 is delayed in rotation by a predetermined amount or more and the back portion 26d of the lock arm 26 abuts against the second cam surface 32b, the pressing action by the second cam surface 32b causes The lock arm 26 can swing in the locking direction.

  Further, a swing lever member 20 pivotally supported by a shaft hole 20a is swingably disposed on a support shaft 19 projecting from the inner surface of the ratchet wheel 18. The swing lever member 20 is appropriately restricted in counterclockwise rotation by a locking projection 8 projecting from the sensor side end surface of the reel 3, and a pressing projection 16 d projecting from the sensor side surface of the pole 16. The reel 3 is assembled between the ratchet wheel 18 and the ratchet wheel 18 so that the rotation in the clockwise direction is appropriately regulated by abutting between the support shaft 19 and the locking projection 8.

  A shaft support portion 34b that rotatably supports the reel 3 via the support shaft pin 6 is provided at the center of the gear case 34 disposed outside the inertia plate 30. The bottom surface of the shaft support portion 34b is provided. , The flange portion 6a of the spindle pin 6 abuts, and serves as a positioning surface in the axial direction of the reel 3. Further, a box-shaped storage unit 50 for storing the vehicle body acceleration sensing means 51 which is an inertial sensing means for sensing the acceleration of the vehicle body is provided below the gear case 34.

  A sensor cover 35 is disposed outside the side plate 1 a that covers the gear case 34. Next, the operation of the seat belt retractor will be described. First, in the normal use state, as shown in FIG. 18, the ratchet wheel 18 is applied to the reel 3 by the urging force of the spring coil 21 and the tension coil spring 36 latched by the latch 17c of the plate 17. The seat 16 is biased in the direction in which the seat belt is pulled out (the direction of the arrow X2 in the figure), and the pole 16 with which the engaging projection 16b engages with the cam hole 18a is biased in the direction in which the engaging tooth 16 is not engaged. ing. Therefore, the reel 3 can rotate and the seat belt can be pulled out freely.

  Thus, when the seat belt acceleration sensing means including the inertia plate 30 or the vehicle body acceleration sensing means 51 is actuated in the event of an emergency such as a collision, the lock arm 26 is a locking means that prevents the lock actuating means from rotating in the seat belt pull-out direction. Alternatively, the sensor arm 53 prevents the ratchet wheel 18 from rotating in the direction in which the seat belt is pulled out, and operates the locking means of the winding device.

  Then, after the vehicle body acceleration sensing means 51 or the seat belt acceleration sensing means is actuated and the rotation of the ratchet wheel 18 in the seat belt withdrawing direction is prevented, when the seat belt is further withdrawn from the winding device, the ratchet wheel 18 Since a rotation delay is caused with respect to the reel 3 and the seat belt is rotated relative to the winding direction of the seat belt (in the direction of the arrow X1), the cam hole 18a of the ratchet wheel 18 causes the engagement protrusion 16b of the pole 16 to have a radius from the rotation center axis of the reel 3. Move outward in the direction. Therefore, the pole 16 is swung and rotated about the support shaft 7 in the direction of engagement with the engagement internal tooth 2 (in the direction of arrow Y1 in FIG. 12).

  Further, when the seat belt is pulled out from the winding device, the engagement teeth 16c of the pole 16 are engaged with the engagement inner teeth 2 to complete. In this state, there is a gap between the pole rear end portion 16e of the pole 16 and the pressure receiving surface 45 of the reel 3, and the swing lever member 20 is connected to the locking protrusion 8 of the reel 3 and the pressing protrusion 16d of the pole 16. The rotation is regulated by almost no play.

  Here, the shaft hole 16a of the pole 16 is loosely fitted to the support shaft 7 of the reel 3, and is pivotally supported by the reel 3 so as to be swingable and rotatable and to be relatively movable by a predetermined amount. Furthermore, when the seat belt is pulled out from the winding device, the pole 16 rotates relative to the reel 3 about the rotation center axis of the reel 3 until the pole rear end portion 16e contacts the pressure receiving surface 45. .

  At this time, the pressing protrusion 16d of the pole 16 is stationary relative to the side plate 1a, but the locking protrusion 8 of the reel 3 rotates in the seat belt drawing direction (arrow X2 direction). By this movement, the rocking lever member 20 is rocked and rotated in the clockwise direction in FIG. 13 by the rocking end portion being pushed by the locking protrusion 8 with the contact point with the pressing protrusion 16d as a rotation fulcrum. When the swing lever member 20 swings and rotates in the clockwise direction in FIG. 13 about the contact point with the pressing protrusion 16 d as a rotation center, the shaft hole 20 a supported by the support shaft 19 of the ratchet wheel 18 rotates the reel 3. It rotates in the seat belt winding direction (in the direction of arrow X1) with respect to the central axis. As a result, the ratchet wheel 18 is reversely rotated with respect to the reel 3 in the seat belt winding direction (arrow X1 direction).

  Therefore, even when the vehicle body acceleration sensing means 51 or the seat belt acceleration sensing means is activated and the lock means of the winding device prevents the reel 3 from rotating in the seat belt withdrawal direction, the rotation in the seat belt withdrawal direction is prevented. The ratchet wheel 18 can bring the sensor arm 53 in the vehicle body acceleration sensing means 51 or the lock arm 26 in the seat belt acceleration sensing means into a free state in which it can be released from engagement with the internal gear 34a of the gear case 34.

  When a greater tension is applied to the seat belt in the locked state of the pole 16, the portion supporting the shaft support portion 34b of the gear case 34 and the shaft 15c of the power transmission unit 15 is deformed, and the reel 3 tends to move upward. . This movement is prevented by the contact surface 3a and groove 3b formed on the reel coming into contact with the engagement inner teeth 2 and the engagement inner teeth 62 (see FIG. 12) on the side plate 1b, respectively, and acts on the seat belt. The tension to be received is received on these surfaces.

  When the vehicle is stopped and the tension applied to the seat belt is released, the ratchet wheel 18 is already disengaged from the internal gear 34a of the gear case 34 of the sensor arm 53 or the lock arm 26. Since the wheel 18 is rotated in the direction of the arrow X2 with respect to the reel 3 by the urging force of the tension coil spring 36, the cam hole 18a of the ratchet wheel 18 brings the engagement protrusion 16b of the pole 16 toward the rotation center axis side of the reel 3. I will move it. At this time, the tension in the pull-out direction acting on the seat belt is released as described above, and the reel 3 can be rotated in the seat belt retracting direction (arrow X1 direction). When the reel 3 rotates in the direction of the arrow X1 until the tip does not interfere with the tip of the engagement inner tooth 2, the pole 16 swings around the support shaft 7 in the direction to release the engagement with the engagement inner tooth 2. The reel 3 is unlocked and the seat belt can be pulled out freely.

  Next, when the seat belt is pulled out by the electric motor 110 from the state in which the seat belt is pulled out, and the entire seat belt is taken up suddenly in accordance with the rotational force of the power transmission mechanism 15, the seat 3 is placed on the reel 3 that has stopped suddenly. Since the inertia plate 30 that is an inertia member of the belt acceleration sensing means rotates in the winding direction as it is, the inertia plate 30 rotates in the winding direction with respect to the reel 3 and rotates with respect to the reel 3 when viewed in the drawing direction of the reel 3. A rotation delay occurs. However, the contact portion 32 of the inertia plate 30 that swings the engagement claw 26b of the lock arm 26 in a direction to engage the internal gear 34a of the gear case 34 has a predetermined amount of rotation delay with respect to the reel 3 of the inertia plate 30. Until reaching the predetermined amount until the rotation delay of the inertia plate 30 relative to the reel 3 reaches a predetermined amount. The engaging claw 26b does not swing in the engaging direction of the internal gear 34a.

  In the embodiment of the present invention, as shown in the lower part of FIG. 12, the electromagnetic actuator 112 is further provided in the lock mechanism configured and operated as described above. As shown in FIGS. 21 and 22, the electromagnetic actuator 112 includes a solenoid (excitation coil) 112a, a coil spring (elastic member) 112b, a flanged plunger (magnetic core) 112c, and the like. Located at the bottom.

  In the normal state, the solenoid 112a is excited. In this state, as shown in FIG. 21, the plunger 112 c does not contact the ball weight 54 and does not affect the lock mechanism 51. When the control unit 200 releases the excitation of the solenoid 112a to lock the seat belt (S38, etc.), the plunger 112c is lifted by the urging force of the spring 112b. The tip of the plunger 112c pushes up the ball weight 54 through the opening at the bottom of the sensor cover 52. When the ball weight 54 is pushed up, the sensor arm 53 is moved upward in the drawing, and the locking projection 53a meshes with the ratchet teeth 18b of the ratchet wheel 18. As a result, the rotation of the ratchet wheel 18 in the direction in which the seat belt is pulled out (the direction of the arrow X2 in FIG. 13) is prevented. When the seat belt is pulled out and the reel 3 is rotated in the pulling-out direction, the pole 16 is moved radially outward of the reel 3 due to the rotation difference between the latched ratchet wheel 18 and the reel 3, and the inner teeth 2 of the frame 1 a are moved. Mesh. Thereby, the rotation of the reel 3 in the drawing direction is prevented.

  In this example, when the excitation current is supplied to the solenoid 112a, the lock operation is not performed, and the lock operation is performed when the excitation current is interrupted. That is, the lock mechanism is activated by supplying a low level activation signal. Therefore, the seat belt can be locked when the power to the seat belt device is shut off.

  FIG. 23 shows another configuration example of the electromagnetic actuator 112. In this example, the electromagnetic actuator includes a solenoid 112a and a plunger 112c attached to the frame, and engages with the plunger 112c at one end, and a central lever 112d and a lever 112d that are pivotally supported rotatably. In the figure, it is constituted by a coil spring 112b for applying a clockwise urging force. When the claw portion of the lever 112d moves and comes into contact with the tooth surface 18b of the ratchet wheel 18, the rotation of the ratchet wheel 18 is prevented and the lock mechanism by the pawl 16 and the inner teeth 2 of the frame is operated.

  In a normal state in which an excitation current is supplied from the control unit 200 to the solenoid 112a, the solenoid 112a pulls the plunger 112c against the coil spring 112b, and a lever that is pivotally supported by the plunger 112c and one end. The claw portion at the other end of 112 d is separated from the ratchet wheel 18. Therefore, the lock mechanism does not operate.

  Next, the CPU cuts off the supply of excitation current from the control unit 200 to lock the seat belt (S38, etc.). The plunger 112c is pulled downward in the figure by the urging force of the coil spring 112b, and the lever 112d is rotated. As a result, the claw portion at the other end of the lever 112d is engaged (engaged) with the teeth 18b of the ratchet wheel, and the rotation of the ratchet wheel 18 in the seat belt withdrawing direction is prevented. When the seat belt is pulled out and the reel 3 is rotated in the pulling-out direction, the pole 16 is moved radially outward of the reel 3 due to the rotation difference between the latched ratchet wheel 18 and the reel 3, and the inner teeth 2 of the frame 1 a are moved. Mesh. As a result, the reel 3 is prevented from rotating in the pull-out direction, and locking is completed.

  As described above, according to the embodiment of the present invention, when the seat belt is mounted, the seat belt having the seat belt slack determined in consideration of the rotation increase at the time of starting the motor and the winding time is mounted. It is given in advance, and the belt winding time in case of emergency is shortened. Remove the slack of the seat belt before the collision to ensure occupant safety.

  In an emergency, after the seat belt is driven to the pull-out side for a while, the seat belt is wound up to reduce the starting load of the motor, and the motor is immediately rotated at a high speed to shorten the belt winding time.

  Further, when a danger is predicted, a necessary amount of slack is secured and maintained in the seat belt, and when the collision becomes inevitable, the seat belt is immediately wound.

  In an emergency, it is determined whether or not the slack amount is a predetermined amount. If there is a predetermined amount, the belt winding is immediately started. If there is no predetermined amount, a predetermined amount of slack is given to the belt, and then the belt is wound to remove the slack of the seat belt in a short time.

  In the above embodiment, the emergency lock mechanism including the vehicle body acceleration sensing means as well as the seat belt acceleration sensing means has been described. However, in the seat belt device of the present invention, only the seat belt acceleration sensing means or only the acceleration sensing means. Of course, a winding device having an emergency locking mechanism of the type provided with

  In the embodiment, a DC motor is used as a motor, but the present invention is not limited to this, and various types of motors can be used.

In addition, instead of the motor, the required slack amount of the seat belt may be adjusted by means of retracting the buckle or means of retracting the lap belt fixing portion.
As described above, in the seat belt device of the present invention, when the motor is started, the seat belt is loosened to the extent necessary for the motor speed to rapidly increase, and the seat belt is wound from the low load state of the motor. Since the seating is started, the seat belt is wound up at a high speed, and the passenger can be quickly restrained to the seat. Moreover, if the slack of the seat belt can be removed in a short time, it is possible to increase the time allocated to the determination of the collision, which is good.

100 Seat belt retractor 200 Control unit 302 Seat belt

Claims (1)

  A reel that winds a seat belt that restrains an occupant to a seat, a motor that rotationally drives the reel, and when the seat belt is wound around the reel, the motor is temporarily driven in the pull-out direction of the seat belt. Control means for controlling the seat belt to be wound at a high speed by loosening the seat belt and then driving the motor in the seat belt winding direction to reduce the load when starting the motor. Seat belt device.

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