JP2008006998A - Seat belt control device, seat belt winding-up device and vehicular safety device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt control device, a seat belt winding-up device and a vehicular safety device capable of making compatible motor driving by a large current at pre-crushing and quietness at a usual use. <P>SOLUTION: Lines of two systems in the case that a noise filter exists and in the case that the noise filter does not exist are provided on a power source line of a motor drive circuit, and switched at emergency and at a usual time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seat belt control device, a seat belt retractor, and a vehicle safety device.

  As a vehicle safety function, there is known a pre-crash safety system that winds up a seat belt when it is determined that it is inevitable that the host vehicle collides with another vehicle or an obstacle. The purpose of this is to correct the posture of the occupant by winding the seat belt and to maximize the effect of the airbag (Non-Patent Document 1).

Nissan Motor Co., Ltd. website (http://www.nissan-global.com/JP/TECHNOLOGY/INTRODUCTION/SAFETY/index.html)

  In recent years, in order to effectively use a motor attached to a seat belt retractor, it has been considered to use a motor in daily operations other than an emergency emergency in which a collision is predicted. For example, it is considered that when the seat belt is attached or detached, the comfort of the seat belt is improved by rotating the motor and performing an assist operation for removing the slack of the seat belt. In such a device intended for daily use, it is necessary to reduce the influence of noise on other devices including accessories such as radios. However, in the above-described prior art, the seat belt is wound up by the motor only in an emergency situation where the distance from the obstacle or the preceding vehicle is narrowed and the collision is predicted by the collision determination controller. It is not considered to reduce the influence of noise on equipment that does not directly affect the running safety of the vehicle.

  Further, as a method of reducing noise generated by the switching element, a method of inserting a filter circuit is known. If a filter circuit capable of withstanding a large current necessary for winding at the time of pre-crash is provided, a control device is provided. There is a problem that the size of the.

  In order to solve the above-described problems, the present invention has a configuration in which two power supply lines with and without a noise filter are provided in the power supply line of the motor drive circuit, and these are switched between an emergency time and a normal time. .

  More specifically, by switching the power line to be used in accordance with the information obtained from the vehicle, the seat belt buckle during normal driving is not passed through the noise filter when the seat belt is retracted when a collision is predicted. When winding the switch, the power is supplied to the motor drive circuit via a noise filter.

  It is possible to achieve both motor driving with a large current during pre-crash and quietness during normal use. Since the capacity of the filter circuit can be matched with the current capacity during normal use, an increase in the size of the filter circuit is suppressed, and the seat belt controller can be reduced in size and cost.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 shows an overview of a pre-crash safety system according to an embodiment of the present invention. Moreover, the structural example of the functional block of the said pre-crash safety system is shown in FIG.

  A seat belt retractor 106 is attached to the vehicle 100, and the seat belt 110 is pulled out of the seat belt retractor 106 and engaged with a buckle provided on the opposite side of the seat via an attachment 107. To do. The seat belt retractor 106 is provided with a motor 90 for winding the seat belt. The motor 90 is driven by a command from the seat belt controller 105. The rotational force of the motor 90 is transmitted to a reel (not shown) around which the seat belt is wound by a transmission mechanism such as a gear mechanism. Details of the drive circuit will be described later.

  The vehicle 100 includes an obstacle sensor 103 that detects a front target (an obstacle or a vehicle), and the collision determination controller 102 recognizes a front obstacle, an obstacle sensor 103, an acceleration sensor 111, a vehicle speed sensor 112, The possibility of a vehicle collision is determined based on information from the shift position information and the like. As the vehicle speed sensor 112, a wheel speed sensor can be used. Although a specific determination method will be described later, the collision determination controller 102 determines that the host vehicle is based on the distance or relative speed to the target detected by the obstacle sensor 103, the vehicle speed detected by the vehicle speed sensor 112, and the like. Determine the risk of collision with the target.

  When the collision determination controller 102 determines that it is impossible or difficult to avoid a collision with the target, the collision determination controller 102 outputs a winding command to the seat belt controller 105. Then, the seat belt controller 105 drives the motor 90 to wind up the seat belt 110. Correct the posture of the occupant 81 and prepare for the deployment of the airbag.

  At this time, the collision determination controller 102 also outputs a command to the brake assist device 104 to cause the vehicle to generate a braking force. At this time, it is desirable to have a configuration for alarming. Note that an operation amount detected from the brake sensor 101 that detects the operation amount of the brake pedal may be received, and the braking force generated in the vehicle may be changed based on the operation amount and the risk of collision. In addition, since the energizing current of the motor 90 when a collision such as the above is predicted requires a large current of about several tens of A, the capacity of the drive circuit can withstand a large current of about several tens of A. .

  In the embodiment shown in FIG. 1, a buckle sensor 108 that detects whether or not the seat belt 110 is engaged, or a seat 109 that is provided on the seat 109 and detects whether or not the occupant 81 is seated. At least one of sensors (not shown) is provided. The seat belt controller 105 is configured to receive signal inputs from these sensors. For example, the seat belt controller 105 controls the motor 90 so as to wind up the seat belt 110 after a predetermined time has elapsed after the engagement of the buckle is released and the occupant leaves the seat. As a result, the seat belt 110 can be rewound to the initial position after the occupant 81 gets off. Further, for example, after the occupant 81 is seated and the buckle is engaged, the motor is controlled so that the seat belt is wound up after a predetermined time has elapsed. As a result, it is possible to remove the slack after the occupant 81 gets on and wears the seat belt 110. In such a winding operation in a situation where the risk of collision is not high, the energization current of the motor 90 is usually about several A.

  Since the motor 90 is PWM controlled, when a current is passed through the motor, motor noise is generated and superimposed on the power source. In the above-described prior art, since the motor is rotated only in an emergency in which a collision is determined, even if the sensitivity of the AM radio is reduced during the motor operation, for example, the driver listens to the radio. Therefore, noise due to motor energization does not become a big problem in actual use.

  However, in this embodiment, since the motor 90 is driven other than in an emergency, it is necessary to reduce the influence on other devices due to the motor drive noise leaking out of the seat belt controller through the power line. That is, it is necessary to suppress the level of noise leaking outside the seat belt controller 105 below a certain standard.

  Here, the PWM signal that controls the rotation of the motor generally has a low frequency of about several tens of kHz, and a large current of up to several tens of A needs to flow through the power supply line. Therefore, when an attempt is made to insert a noise suppression filter into the power supply line, the filter becomes a large component corresponding to a low frequency and a large current, and there is a problem that a reduction in size and a reduction in cost cannot be realized. In order to solve this problem, in this embodiment, the seat belt controller 105 is configured as follows.

  FIG. 3 is a block diagram of the seat belt controller 105 according to one embodiment of the present invention.

  In FIG. 3, 1 and 2 are relays for switching ON / OFF of power supply from the vehicle-mounted battery, 3 and 4 are drive circuits for the relays 1 and 2, 5 is an LPF for removing motor drive noise, and 6 is motor drive noise. A relay for switching insertion / non-insertion of an LPF (low pass filter) 5 for removal, 7 is a drive circuit (H bridge circuit) for driving the motor, 8 is a drive circuit for the relay 6, and 9 is an H bridge circuit. A pre-driver for control, 10 is a microcomputer, 11 is a bypass capacitor of a motor drive power source, and 90 is a motor for winding up the seat belt 110. The cut-off frequency of the LPF is determined based on the frequency of the PWM signal for driving the motor, the assumed rotation speed of the motor, and the like, but is preferably at least 10 kHz or less.

  Here, the seat belt controller 105 includes a power supply circuit 21 that receives power supply (VBAT) from a vehicle-mounted battery and supplies power to the microcomputer 10, and a CAN transceiver 22 that communicates with the outside. In addition, a signal input from the brake sensor 101 and the buckle sensor 108 (or the seating sensor) is received.

  When the power supply of the seat belt controller 105 is activated, the microcomputer 10 monitors the vehicle battery voltage that is divided by the resistance and taken into the A / D input. If the monitored battery voltage is in the normal range, it is determined that there is no abnormality such as a battery line ground fault or ground fault, the relay drive circuits 3 and 4 are turned on, and the contacts of the relays 1 and 2 are connected.

The seat belt controller 105 controls the rotation of the motor 90 provided in the seat belt retractor 106 and the switching of the relay 6 based on the CAN input from the collision determination controller 102, the input from the brake sensor 101, and the input from the buckle sensor 108. Control (LPF insertion / non-insertion) is performed. Note that immediately after the seat belt controller 105 is started, the relay 6 is connected to the contact A and the LPF is inserted. This is because the seat belt controller 105, door unlocking, key ON or ignition ON is activated, so that the vehicle is not running in that state, and it is normally not considered that pre-crash safety control is performed. Further, even if the vehicle may be activated during traveling, for example, the seat belt is attached or detached by a signal from the buckle sensor 108 (or the seating sensor), and the microcomputer 10 assists in winding the seat belt 110 ( When the microcomputer 10 detects that the conditions for slack removal and fitting (winding for fitting) are satisfied, the microcomputer 10 outputs the PWM signal for controlling the motor 90, the rotation direction, and the like to the pre-driver 9, and constant conditions such as current, duty, etc. The H bridge circuit 7 is operated so as to rotate the motor 90. At this time, if a device sensitive to motor noise such as an AM radio of a vehicle is operating, other connected devices may be disturbed by motor drive noise. However, the power source of the H bridge circuit is configured by LC. Since the LPF 5 is inserted, the motor drive noise can be prevented from leaking from the power supply line. Here, normally, the motor energization current used for assisting in winding the seat belt is several A. Since this current value is lower than the current value (several tens of A) in winding the seat belt before the collision, the LPF 5 may have a capacity assuming a driving current of several A, and assumes a current capacity of several tens of A. It can be constituted by a relatively small component.

  Next, the operation when the collision determination controller predicts a collision and winds up the seat belt to correct the occupant's posture before the collision will be described.

  Immediately after the seat belt controller 105 is activated, the relay 6 is connected to the contact A side with LPF. Thereafter, when a collision is predicted by the collision determination controller 102, information is transmitted to the seat belt controller 105 by CAN communication, and the contact of the relay 6 is switched to the contact B side.

  When it is necessary to wind up the seat belt 110 in this state, the microcomputer 10 outputs a PWM signal to the pre-driver, and operates the H-bridge circuit so as to energize the motor with a current for restraining the occupant to the seat. . The determination of when to switch the relay 6 and when to wind up the seat belt 110 will be described later.

  When the relay 6 is switched to the contact B side, if another connected device sensitive to motor noise such as AM radio is operating, the other connected device may be disturbed by the motor driving noise. However, since the vehicle is an emergency immediately before a collision and is in an emergency state where safety is a top priority, even if interference occurs in the other connected devices, there is no practical problem.

  By configuring as described above, when the seat belt is taken up in an emergency, it is possible to pass the current by bypassing the LC filter. As a result, it is not necessary to arrange an LC filter in consideration of a large current in an emergency, and it can be configured by a relatively small filter, so that a compact and low-cost seat belt controller can be configured.

  In this embodiment, the LPF is used for the motor drive noise removing filter. However, the filter need not necessarily be an LPF, and the filter characteristic has an attenuation characteristic only in a part of the frequency band in accordance with the noise characteristic to be removed. It can be replaced with a trap-type filter.

  FIG. 4 is a flowchart for explaining the flow of LPF insertion / non-insertion switching processing in the seat belt controller 15 shown in FIG.

The collision determination controller monitors the distance L and the relative speed V with respect to the vehicle in front of the vehicle based on information from an obstacle sensor such as a radar (step 001), and calculates a collision prediction time (T = L / V) from the result. (Step 002). On the other hand, the collision determination controller monitors the vehicle speed by the vehicle shift position and the wheel speed sensor. Here, for example, when the vehicle is moving backwards, such as when entering a garage, or when the vehicle is operating at an extremely low speed such that the bumper is recessed even if it collides, the seat belt is retracted by collision prediction. Is not performed (step 003). Even when it is determined that the occupant has removed the seat belt based on the output of the buckle sensor 108 described above, the seat belt is not retracted by the collision prediction.

  When the vehicle speed and the shift position satisfy the regulations, the possibility of collision is determined based on the predicted collision time L. If L is less than a certain threshold, it is determined that there is a collision, and if L is greater than or equal to the threshold, it is determined that there is no collision, and the process returns to step 001 to continue observation of L and V (step 004). .

  If it is determined that there is a collision, the seat belt controller 105 first switches the LPF insertion / non-insertion switching relay 6 to de-insert the LPF of the H-bridge circuit power supply (steps 005, 006). In a seatbelt retractor with a motor (motor seatbelt retractor), after a belt clamp mechanism is locked, a specified current is applied to the motor to apply a constant tension to restrain the occupant. Due to the tension of the seat belt generated at this time, the occupant is fastened to the seat and the posture is corrected (steps 007 and 008). After the occupant is restrained by winding the seat belt, the collision determination controller detects whether a collision has actually occurred or avoided based on information from the acceleration sensor (step 009). If a collision is detected, the second seat belt is retracted due to the explosive explosion of the pretensioner and the occupant is completely restrained (at this time the vehicle will open the airbag), and the seat belt is completely retracted. (Steps 010 and 011).

  On the other hand, if no collision is detected even after the predicted collision time T has elapsed, the reverse rotation of the motor and the unlocking of the belt clamp mechanism are performed, and the seat belt retractor (pretensioner) 106 and the seat belt 110 are The state is returned to the initial state (steps 013 and 014). The seat belt controller 105 switches the LPF insertion / non-insertion switching relay 6 of the power supply for the H bridge circuit and inserts the LPF 5 (steps 015 and 016).

  FIG. 5 is another example of a flowchart for explaining the flow of LPF insertion / non-insertion switching processing of the power supply line for the H-bridge circuit of the seat belt controller.

  When the child seat attachment switch set in advance in the vehicle is turned ON (step 031), the seat belt controller switches the LPF switching relay of the power supply line for the H-bridge circuit, and the LPF is not inserted (step 032). , 033). In the seat belt retractor with motor, the belt clamp mechanism is locked (step 034). In the seat belt controller, the tension of the seat belt is generated by winding the motor, and the child seat is fixed to the seat (step 035). After the winding is completed, the belt clamp mechanism of the seat belt retractor with motor is released, and then the LPF switching relay of the power supply line for the H bridge circuit is switched to return to the initial state where the LPF is inserted (steps 036 to 039). ).

  As explained above, the noise filter is inserted into the power supply for the H-bridge circuit when switching the seat belt when the seat belt buckle switch is attached / removed during daily operation, so noise can be reduced. is there. On the other hand, since the noise filter is not inserted and removed by switching the switch when the seat belt is rolled up immediately before the collision, the noise filter can be designed with a low motor current for daily operation. For this reason, it is possible to reduce the current capacity required for the noise filter, and since it can be configured with small parts compared to the case where the present invention is not applied, the set can be reduced in size and cost. it can.

  This switching is performed before the seat belt 110 is actually wound. For example, when it is notified from the collision determination controller 102 that a collision has been predicted, the relay 6 is immediately switched, and the motor is driven promptly after the switching is completed. In addition, when the collision determination performed by the collision determination controller 102 is made in stages, for example, when it is possible to separately determine and notify “a situation where collision can be avoided but attention is required” and “a situation where collision cannot be avoided”, The relay 6 may be switched when the seat belt controller 105 receives the former signal, and the motor 90 may be driven when the latter signal is received.

  FIG. 6 is a block diagram of the seat belt controller 105 according to one embodiment of the present invention. The difference from FIG. 3 is that instead of relays 2 and 6, a twin type relay 12 is used. By using a relay having two interlocked contacts, the relay drive circuit 4 is omitted. Therefore, it is possible to configure the seat belt controller with a smaller and less expensive circuit. Moreover, since the number of relays to be controlled is limited to one from the viewpoint of the microcomputer, there is an effect that there is no need to consider the software load and the delay time that occurs when switching between the A and B contacts. The configuration and operational effects not specifically described are the same as in the embodiment shown in FIG.

FIG. 7 is a block diagram of the seat belt controller 105 according to one embodiment of the present invention. 3 differs from the relays 1, 2, 6 in that the semiconductor switches 13, 14,
15 is used, and since no mechanical contact is used, the problem of contact life is eliminated. Therefore, the same effect as in FIG. 3 can be obtained with a longer life configuration. It should be noted that configurations and operational effects that are not particularly described are the same as those in the embodiment shown in FIG.

  FIG. 8 is a block diagram of the seat belt controller 105 according to one embodiment of the present invention. A difference from FIG. 6 is that semiconductor switches 13 and 16 are used instead of the relays 1 and 12, and a longer-lifetime configuration can be obtained as in the configuration of FIG. It should be noted that configurations and operational effects that are not particularly described are the same as those in the embodiment shown in FIG.

  FIG. 9 is a block diagram of a seat belt controller according to an embodiment of the present invention.

  3, 5, and 6 is that the relay drive circuit 8 is driven using a PWM signal that controls the pre-driver, and the microcomputer does not need to control the relay drive circuit. That is, since the relay is automatically switched based on the magnitude of the current supplied to the motor, the burden of microcomputer software processing can be reduced. It should be noted that configurations and operational effects that are not particularly described are the same as those of the embodiment shown in FIGS.

It is a block diagram explaining a pre-crash safety system. It is a block block diagram explaining the structure of a pre-crash safety system. It is a block block diagram of the seatbelt controller concerning 1st Example of this invention. It is a flowchart explaining LPF insertion and non-insertion switching. It is a flowchart explaining LPF insertion and non-insertion switching. It is a block block diagram of the seatbelt controller concerning 2nd Example of this invention. It is a block block diagram of the seatbelt controller concerning the 3rd Example of this invention. It is a block block diagram of the seatbelt controller concerning 4th Example of this invention. It is a block block diagram of the seatbelt controller concerning 5th Example of this invention.

Explanation of symbols

1, 2, 6, 12 ... relay, 3, 4, 8 ... relay drive circuit, 5 ... LPF, 7 ... H bridge circuit, 9 ... pre-driver, 10 ... microcomputer, 11 ... power supply bypass capacitor, 13,
DESCRIPTION OF SYMBOLS 14, 15, 16 ... Semiconductor switch, 21 ... Power supply circuit, 22 ... CAN transceiver, 23 ... EEPROM, 81 ... Passenger, 90 ... Motor, 101 ... Brake sensor, 102 ... Collision judgment controller, 103 ... Obstacle sensor, 104 ... Brake assist device, 105 ... Seat belt controller, 106 ... Motor seat belt retractor, 106a ... Motor seat belt retractor (driver's seat side), 106b ... Motor seat belt retractor (passenger seat side), DESCRIPTION OF SYMBOLS 107 ... Attaching tool, 108 ... Buckle sensor, 109 ... Seat, 110 ... Seat belt, 111 ... Acceleration sensor, 112 ... Vehicle speed sensor, 113 ... Shift position information.

Claims (11)

A drive circuit that drives a motor that winds up the seat belt;
A first power supply path for supplying power to the drive circuit from a power source through a noise removing unit;
A second power supply path for supplying power from the power source to the drive circuit without going through the noise removing means;
A seat belt control device comprising switching means for switching between the first power supply path and the second power supply path based on an external signal. In claim 1,
The seat belt control device, wherein the first power supply path is selected when an emergency signal is input from the outside. In claim 1 or 2,
The switching means is
A relay that switches between the first power supply path and the second power supply path;
A seatbelt comprising: a determination unit that determines which of the first power supply path and the second power supply path is selected based on a signal from the outside and controls the relay. Control device. In claim 3,
The switching means is
A seat belt control device, wherein the seat belt control device is a twin-type relay that simultaneously switches contacts provided upstream and downstream of the first power supply path and the second power supply path. In claim 1 or 2,
The switching means is
A semiconductor switch for switching between the first power supply path and the second power supply path;
A sheet comprising: a determination unit that determines which one of the first power supply path and the second power supply path is selected based on a signal from the outside, and controls the semiconductor switch. Belt control device. In claim 5,
The seat belt control device characterized in that the switching means simultaneously switches semiconductor switches provided upstream and downstream of the first power supply path and the second power supply path. A drive circuit that drives a motor that winds up the seat belt;
A first power supply path for supplying power to the drive circuit from a power source through a noise removing unit;
A second power supply path for supplying power from the power source to the drive circuit without going through the noise removing means;
A seat belt control device comprising switching means for switching between the first power supply path and the second power supply path based on the drive current of the motor. A drive circuit that drives a motor that winds up the seat belt;
A first power supply path for supplying power to the drive circuit from a power source through a noise removing unit;
A second power supply path for supplying power from the power source to the drive circuit without going through the noise removing means;
Switching means for switching between the first power supply path and the second power supply path;
The motor is PWM-controlled, and the switching means switches between the first power supply path and the second power supply path based on the PWM signal. In any one of Claims 1 thru | or 8,
The seat belt control device according to claim 1, wherein the driving circuit is an H-bridge circuit, and the noise removing means is a low-pass filter. A seat belt control device according to any one of claims 1 to 8,
A reel that winds up the seat belt,
A seat belt retractor comprising a motor driven by the seat belt controller and transmitting power to the reel. The seat belt retractor according to claim 9,
A seat belt that can be worn by a passenger seated in the seat;
Obstacle detection means for detecting obstacles ahead of the vehicle;
A vehicle safety device comprising: collision determination means for determining the possibility of collision with an obstacle when an obstacle is detected and outputting a signal to the seat belt control device.

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