JP2014121972A - Seat belt device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt device capable of keeping restraint performance on emergency without being affected by differences in wire lengths.SOLUTION: When a drive request of driving a first motor taking up the seat belt of a first seat and a second motor taking up the seat belt of a second seat is received, a second control part starts supply of a second driving current to the second motor through a second wire having a wire length greater than that of a first wire on detecting instability of the behavior of a vehicle, and, after the second control part starts supply of the driving current, a first control part starts supply of a driving current to the first motor through the first wire.

Description

  The present invention relates to a seat belt device.

  For example, Patent Document 1 discloses a seat belt device in which a motor and a control unit are integrated for each seat, the control units are connected only by signal lines, and can operate independently for each seat.

  According to the technique disclosed in Patent Document 1, each control unit has a motor control function, and thus each control unit includes a motor drive circuit. The motor-equipped seat belt retractor is attached to a seat belt provided on a driver seat and a passenger seat, and is attached to a vehicle body on the side of the seat. The control unit on the driver seat side and the control unit on the passenger seat side are respectively molded on the seat belt retractors on the driver seat side and the passenger seat side, or are structurally attached by brackets or the like. The control unit on the driver's seat side and the control unit on the passenger's seat side are electrically connected to the motors of the seat pel retractors on the driver's seat side and the passenger's seat side, respectively, by bus bars, connectors, and the like.

  The control unit calculates a target current and a target speed when driving the motors on the driver's seat side and the passenger's seat side based on the amount of seat belt drawn and retracted, and controls the drive current of each motor. Further, when the drive current actually energized to each motor is converged to the target current, for example, the drive current energized to each motor is estimated from the rotational speed of the belt reel for each seat belt, and the estimation result is obtained. The drive current of each motor is controlled so as to converge to the target current.

JP 2008-056075 A

  By the way, according to the technique disclosed in Patent Document 1, each motor of the seat belt in the driver's seat or the passenger's seat and the control unit are disposed relatively close to each other. And the wiring length between the control units is different. For this reason, if a drive current is supplied to each motor via a harness connected to the same power source, a large amount of current flows through the shorter harness (wire resistance is low), and the voltage drop of the harness between the driver seat and the passenger seat Due to this difference, a situation occurs in which the restraining force of the seat belt in each seat is different. For this reason, when an emergency situation arises, there is a possibility that an appropriate restraint force by the seat belt cannot be given to the user.

  The motor is driven by a PWM (Pulse Width Modulation) circuit whose cycle is constant and whose pulse width duty ratio (ratio of pulse width H and L) changes according to the magnitude of the input signal (DC level). The PWM circuit controls the energization amount and energization direction of the drive current. FIG. 8A shows a timing chart for driving two motors (R motor and L motor) when the duty ratio is 50%, and FIG. 8B is a duty ratio of 80%. As is apparent from FIGS. 8A and 8B, when the R motor and the L motor are driven simultaneously, the larger the duty ratio, the more current flows through one motor, and as a result, the other motor takes up the winding. The restraining force of the seat belt to be reduced will be reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a seat belt device capable of maintaining the restraining performance in an emergency without being affected by the difference in wiring length. is there.

  According to the first aspect of the present invention, a first motor that winds up the seat belt of the first seat, a first control unit that controls the winding of the first motor, and a second seat A second motor that winds up the seat belt; a second controller that controls the winding of the second motor; and a second motor that supplies a driving current to the first motor from the first controller. 1 electric wire, a second electric wire that supplies a driving current from the second control unit to the second motor and has a longer wire length than the first electric wire, and vehicle state detection that detects the behavior of the vehicle And when the driving request for driving the first motor and the second motor is received, the second control unit is configured such that the vehicle state detection unit is unstable in the behavior of the vehicle. Is detected, the drive current of the drive current is transmitted to the second motor via the second electric wire. The first control unit starts supplying the drive current to the first motor via the first electric wire after the second control unit starts supplying the drive current. Is a seat belt device characterized by the above.

  According to a second aspect of the present invention, in the seat belt device according to the first aspect, the first control unit and the second control unit are configured such that the first motor is based on a pulse width signal generated by pulse width modulation. And the second motor are driven, and when the vehicle state detection unit detects that the behavior of the vehicle is unstable, the first control unit performs the second control by the second control unit. Output the pulse width ON signal to the first motor via the first electric wire when the pulse width ON signal to the second motor via the first electric wire is first switched to the OFF signal. Features.

  According to the seat belt device of the first aspect, the first motor that winds the seat belt of the first seat (for example, the driver's seat) and the seat belt of the second seat (for example, the passenger seat) are wound. When the second control unit detects that the behavior of the vehicle is unstable when it receives a drive request for driving the second motor that performs the removal, the second motor is longer than the first electric wire. The supply of the second drive current is started via the second electric wire having the wire length, and the first control unit supplies the first motor to the first motor after the start of the supply of the drive current by the second control unit. The supply of drive current is started via the electric wire. For this reason, when the behavior of the vehicle is unstable, by providing a time difference in driving the first motor and the second motor, it is possible to avoid a large amount of current flowing in one side and a decrease in the other binding force, and the seat The binding force of the belt can be maximized. That is, the restraint performance of the seat belt in the first seat and the second seat can be maintained without being affected by the difference in wiring length between the first electric wire and the second electric wire.

  According to the seat belt device of the second aspect, when detecting that the behavior of the vehicle is unstable, the first control unit supplies the second motor to the second motor via the second electric wire. When the second pulse width ON signal is first switched to the OFF signal, the pulse width ON signal is output to the first motor via the first electric wire. As described above, the restraint performance in an emergency can be maintained without being affected by the difference in the wiring length by shifting the period in consideration of the maximum current flowing at the start of the seat belt winding.

It is a hardware block diagram of the seatbelt apparatus by embodiment of this invention. It is a block diagram which shows the internal structure of the electrical equipment system of the seatbelt apparatus by embodiment of this invention. It is a flowchart which shows operation | movement of the seatbelt apparatus of FIG. It is a timing chart which shows operation | movement of the seatbelt apparatus of FIG. It is a timing chart which shows operation | movement of the seatbelt apparatus of FIG. It is a timing chart which shows operation | movement of the seatbelt apparatus of FIG. It is a timing chart which shows operation | movement of the seatbelt apparatus of FIG. It is a timing chart which shows operation | movement of the conventional seatbelt apparatus.

  Hereinafter, a seat belt device according to an embodiment of the present invention (hereinafter simply referred to as the present embodiment) will be described in detail with reference to the drawings.

(Configuration of the embodiment)
The seat belt device 1 according to the present embodiment is applied to a so-called three-point seat belt capable of restraining an occupant 3 seated on a seat 2 as shown in FIG. In the seat belt device 1, a belt 5 is drawn upward from a retractor 4 attached to a center pillar (not shown), and the belt 5 is inserted into a through anchor 6 supported on the upper side of the center pillar. 5 is fixed to the vehicle body floor via an outer anchor 7 on the outside of the passenger compartment of the seat 2.

  A tongue plate 8 is inserted between the through anchor 6 and the outer anchor 7 of the belt 5, and the tongue plate 8 can be attached to and detached from the buckle 9 fixed to the vehicle body floor near the vehicle body of the seat 2. It has become. The buckle 9 includes a buckle switch (not shown). The buckle switch is turned on when the tongue plate 8 is engaged with the buckle 9 and turned off when the tongue plate 8 is detached from the buckle 9. Become.

  The belt 5 is configured to be retractable by a spring and a motor (not shown) constituting the retractor 4. In the retractor 4, a belt 11 is wound around a belt reel rotatably supported by a casing, and a speed reducer made of a planetary gear or the like is engaged with a belt reel shaft protruding to one end side of the casing. On the other hand, a power transmission device composed of a plurality of gear groups is connected to the output shaft of the motor, and the power transmission device and the speed reducer are linked via a clutch so that they can be connected and disconnected. A spring is engaged with the shaft of the belt reel protruding from the other end side of the casing into the spring case, and the belt reel is urged in the winding direction by this spring.

  The belt 5 is wound around a belt reel in an initial state, and the occupant 3 pulls it out by hand and fixes the tongue plate 8 to the buckle 9, so that the chest and abdomen of the occupant 3 are mainly attached to the seat 2. to bound. When the occupant 3 releases the buckle 9 and detaches the tongue plate 8 from the buckle 9, the buckle switch is turned off, and the belt 5 is wound around the belt reel by a spring and a motor and stored in the retractor 4. Furthermore, in the seat belt device 1, the emergency pull-in (pre-tension) of the belt 5 by the motor is performed in an emergency such as a collision, and the restraining effect on the occupant is strengthened.

  The pretensioner unit 20 controls the winding operation of the belt 5 by the retractor 4 by obtaining necessary power from the power supply 30 and energizing the motor. A seat belt device 1 including a retractor 4 and a pretensioner unit 20 having the same configuration is disposed in each of the driver seat and the passenger seat of the vehicle. Here, only the configuration of the seat belt on the driver's seat side where the occupant 3 operates the steering handle 13 is shown. In the following description, R indicates the driver's seat side, L indicates the passenger seat side, and when it is necessary to distinguish, the reference numerals are also appended with “R” and “L”.

  FIG. 2 shows an internal configuration of the electrical system of the seat belt device 1 including the pretensioner unit 20 according to the present embodiment. As shown in FIG. 2, the seat belt device 1 according to the present embodiment includes a first motor (R motor for the R seat belt retractor 4 </ b> R) that winds up the seat belt of the first seat (for example, the driver's seat R). A first control unit (R pretensioner unit 20R) that controls the winding of the first motor, and a second motor that winds up the seat belt of the second seat (for example, the passenger seat L) ( L seat belt retractor 4L L motor), a second control unit (L pretensioner unit 20L) that controls the winding of the second motor, and a first control unit that supplies drive current to the first motor Including a first electric wire (harness 90R) and a second electric wire (harness 90L) having a longer wire length than the first electric wire for supplying a driving current from the second control unit to the second motor. .

  The R pretensioner unit 20R includes a CAN communication unit 201, a vehicle state detection unit 202, a motor drive control unit 203, and a power supply unit 204 with the control unit 200 as a control center. The L pretensioner unit 20L also has the same configuration.

  The control unit 200 includes, for example, a microprocessor and a memory, and executes the following processing by sequentially reading and executing a program recorded in the memory. That is, when the control unit 200 receives a drive request for driving the R motor of the R seatbelt retractor 4R, when the vehicle state detection unit 202 detects that the behavior of the vehicle is unstable, the control unit 200 Supply of drive current via the harness 90R is started. At this time, the control unit of the L pretensioner unit 20L starts to supply drive current to the L motor via the harness 90L after the control unit 200 of the R pretensioner unit 20R starts to supply drive current.

  Specifically, the control unit 200 of the R pretentive unit 20R drives the first motor (R motor) with a pulse width signal generated by PWM. At this time, the L pretensioner unit 20L (control unit) drives the second motor (L motor) with a pulse width signal generated by PWM. However, when the vehicle state detection unit 202 detects that the behavior of the vehicle is unstable, the control unit 200 performs the second operation via the second electric wire (harness 90L) by the L pretensioner unit 20L (control unit). When the PWM signal ON to the motor is first switched OFF, the PWM signal ON is output to the first motor via the first electric wire (harness 90R). This shift in drive timing will be described later.

  The CAN communication unit 201 includes an ACC (Adaptive Cruise Control) unit 40, a CMBS (Collision Mitigation Brake System) unit 50, a VSA (Vehicle Stability Assist) connected via a CAN (Control Area Network) 80 standardized by ISO 11898 and ISO 11519. It manages the communication interface with the unit 60. The ACC unit 40 is an obstacle detection unit, the CMBS unit 50 is a rear-end collision reduction brake, and the VSA unit 60 is a control unit provided for vehicle behavior stabilization. Both the ACC unit 40 and the CMBS unit 50 detect an obstacle or a preceding vehicle using a millimeter wave radar, and perform an operation (pre-crash) for collision avoidance or impact reduction when it is determined that there is a possibility of a collision. .

  These units 40, 50, 60 include means for detecting the running state of the vehicle, such as relative speed, inter-vehicle distance, yaw rate, slip angle, acceleration, vehicle speed, and the like. The R pretensioner unit 20R and the L pretensioner unit 20L Necessary information is mutually communicated via the CAN 80. The SRS (Supplement Restrain System) unit 70 that controls the airbag and has an auxiliary restraint function of the seat belt by the R pretensioner unit 20R and the L pretensioner unit 20L is an R pretensioner unit 20R and an L pretensioner unit 20L. Necessary information is directly communicated with each other without using the CAN 80. The SRS unit 70 is connected to various sensors necessary for airbag deployment, such as a buckle switch, a roll, and a pitch.

  The motor drive control unit 203 incorporates a motor drive circuit, and controls the energization amount, energization direction, and energization timing of the drive current energized to the R motor of the R seat belt retractor 4R under monitoring by the control unit 200. . The motor driving circuit includes, for example, four switching elements, and a high side arm composed of two switching elements connected to the positive terminal of the power supply 30 and a low side arm composed of two switching elements connected to the ground terminal are bridged. Connected and configured as a so-called H-bridge. The motor drive control unit 203 outputs a pulse signal by PWM for driving each switching element constituting the H bridge ON / OFF. The duty ratio of the pulse signal is set by a predetermined arithmetic expression based on the target current, the target speed, each sensor value indicating the vehicle state, and the like.

  Therefore, the motor drive control unit 203 includes a current detection unit 203a and an energization amount control unit 203b that incorporates a PWM circuit. The energization amount control unit 203b controls the energization amount and the energization timing in accordance with a control signal generated by the control unit 200 based on the behavior state of the vehicle output by the vehicle state detection unit 202, and the R seat belt retractor 4R. PWM signal is supplied to the R motor. The current detection unit 203a is used for abnormality detection that detects a current that actually flows through the R motor.

  The power supply unit 204 receives electric power (+ B) from an in-vehicle battery (not shown) and supplies a driving current to the motor 4R. The above description has been given of the configuration centered on the R pretensioner unit 20R, but the L pretensioner unit 20L also has the same configuration, and in FIG. 2, the internal configuration is omitted. Similarly to the R pretensioner unit 20R, the L pretensioner unit 20L receives power (+ B) from an in-vehicle battery (not shown) and supplies drive current to the motor 4L. In addition, the L pretensioner unit 20L is communicably connected to the SRS unit 70. It is connected to the ACC unit 40, the CMBS unit 50, and the VSA unit 60 via the CAN 80.

(Operation of the embodiment)
Hereinafter, the operation of the seat belt device 1 according to the present embodiment will be described in detail with reference to the flowchart of FIG. 3 and the operation timing diagrams shown in FIGS. 4 to 7.

  First, the control unit 200 of each of the R pretensioner unit 20R and the L pretensioner unit 20L receives the acceleration and the acceleration necessary for the vehicle state detection unit 202 to detect the behavior of the vehicle via the CAN 80 or the SRS unit 70. Various sensor signals such as the vehicle speed are acquired (step S100). Here, the behavior of the vehicle refers to the behavior of the vehicle due to operations (pre-crash) such as side slip, collision avoidance, or impact reduction at the time of collision.

  Next, the control unit 200 determines whether or not there is a drive request for the R seat belt retractor 4R. The drive demanded here means that, for example, when there is a side-sliding operation of the vehicle controlled by the VSA unit 60, the belt 5 must be urgently drawn by the R motor as in the pre-crash controlled by the CMBS unit 50. In this case, or in order to avoid an emergency condition, the motor 4R needs to be rotated in the reverse direction in order to release the clutch of the R seat belt retractor 4R to make it tension free. If there is no drive request (step S101 “NO”), the execution of this routine is temporarily terminated.

  When it is determined that there is a drive request (step S101 “YES”), the R pretensioner unit (control unit 200) cooperatively drives the L motor and the R motor through communication with the L pretensioner unit 20L via the CAN 80. The target current value including the duty ratio is calculated as much as possible to control the motor drive control unit 203 (step S102).

  Here, when the vehicle state detection unit 202 detects a side-slip operation by the VSA unit 60 in which the behavior change of the vehicle is relatively slight (step S103 “YES”), the control unit 200 controls the motor drive control unit 203. For example, as shown in FIGS. 4 (a) and 4 (b), the L motor of the L seat belt retractor 4L is delayed by 50 μs compared to the R motor of the R seat belt retractor 4R, and control to start PWM driving is performed ( Step S104).

  That is, the energization amount control unit 203b performs control to start up the drive current supplied to the L motor connected via the long harness 90L earlier than the R motor connected via the short harness 90R. FIG. 4A shows the drive current I on the vertical axis and the current values of the R motor and the L motor and the drive timing when the time t is scaled on the horizontal axis, and FIG. The vertical axis represents the PWM signal, and the horizontal axis represents the drive timing of the R motor and the L motor when the time t is scaled. The same applies to FIGS.

  On the other hand, when the side-slip operation is not detected (step S103 “NO”), the control unit 200 further determines the presence or absence of the pre-crash operation that makes the behavior of the vehicle unstable (step S105). Here, when the vehicle state detection unit 202 detects, for example, a pre-crash operation for impact reduction such as collision avoidance by the CMBS unit 50 or impact reduction at the time of collision (step S105 “YES”), the control unit 200 By controlling the motor drive control unit 203, for example, as shown in FIGS. 5 (a) and 5 (b), the L motor of the L seat belt retractor 4L is delayed by 80 μs compared to the R motor of the R seat belt retractor 4R. Control for starting the PWM drive is performed (step S106).

  That is, the energization amount control unit 203b sends the drive current supplied to the L motor of the L seat belt retractor 4L connected to the L pretentive unit 20L via the long harness 90L via the R pretentive unit 20R and the short harness 90R. Is configured so as to start up more slowly than the R motor of the R seat belt retractor 4R connected to the vehicle, and because the degree of instability of the vehicle behavior is large (side slip <pre-crash), the delay time is further different. It was.

  In FIG. 3, it is described that the presence or absence of the pre-crash is determined in step S105 and the R motor of the R seat belt retractor 4R is delayed by 80 μs. However, this delay time is not limited, and the pre-crash Instead, the control may be triggered by behavioral instability factors such as assist brakes and sudden turning. For example, as shown in FIGS. 6A, 6B and 7A, 7B, when the wiring length is greatly different between R and L and the difference in resistance value is further increased, the peak value of the current is increased. Therefore, it is possible to change the delay amount from 1 ms to 10 ms while keeping the PWM phase as it is.

  On the other hand, when the pre-crash operation is not detected by the vehicle state detection unit 202 (step S105 “NO”), the control unit 200 is able to During the slack removal operation, the motor drive control unit 203 is controlled so as to perform drive control in the comfort mode in which priority is given to wearing comfort of the occupant (step S107). Control unit 200 repeatedly executes the processes of steps S103 to S107 until vehicle state detection unit 202 detects the end of the pre-crash (step S108 “YES”). When the end of the pre-crash operation is detected (step S108), the control unit 200 stops the delay drive control with the shorter harness (step S109) and ends the processing according to this routine.

(Effect of embodiment)
According to the seat belt device 1 according to the present embodiment, when the behavior of the vehicle is unstable, the first motor (the R motor of the R seat belt retractor 4R) and the second motor (the L motor of the L seat belt retractor 4L). ) Is provided with a time difference, it can be avoided that a large amount of current flows in one side and the restraining force of the other seat belt is reduced, and the restraining force of the seat belt can be maximized. That is, the first seat (driver's seat R) and the second seat (passenger seat L) are not affected by the difference in wiring length between the first electric wire (harness 90R) and the second electric wire (harness 90L). The restraint performance of the seat belt at can be maintained.

  In consideration of the fact that the control unit (R pretensioner unit 20R or L pretensioner unit 20L) does not function in the event of an emergency and the energization control of the R motor or L motor cannot be performed. The pretensioner units 20R may be alternately arranged on the L seat belt retractor 4L on the passenger seat side, and the L pretensioner units 20L on the passenger seat side may be alternately arranged on the R seat belt retractor 4R on the driver seat side to control the respective motors. . The present invention can be applied to such a case where the difference in the restraining force of the seat belt due to the difference in the wiring length is more conspicuous, and a remarkable effect can be obtained. As described above, according to the seatbelt device 1 according to the present embodiment, it is possible to maintain emergency restraint performance without being affected by the difference in wiring length.

  As mentioned above, although preferred embodiment of this invention was explained in full detail, it cannot be overemphasized that the technical scope of this invention is not limited to the range as described in embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiments. Further, it is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus, 4R ... R seat belt retractor, 4L ... L seat belt retractor, 20 ... Pre-tensioner unit, 20R ... R pre-tensioner unit, 20L ... L pre-tensioner Unit 30... Power supply 40. ACC unit 50. CMBS unit 60... VSA unit 70... SRS unit 80. ... CAN communication unit, 202 ... vehicle state detection unit, 203 ... motor drive control unit, 203a ... current detection unit, 203b ... energization amount control unit, 204 ... power supply unit

Claims (2)

A first motor that winds up the seat belt of the first seat, a first control unit that controls the winding of the first motor, and a second that winds up the seat belt of the second seat A second control unit that controls winding of the second motor, a first electric wire that supplies a driving current from the first control unit to the first motor, and the second control unit A second electric wire having a longer wire length than the first electric wire for supplying a driving current from the control unit to the second motor, and a vehicle state detecting unit for detecting the behavior of the vehicle,
When the second control unit receives the drive request for driving the first motor and the second motor, the second control unit detects that the behavior of the vehicle is unstable. The supply of drive current to the second motor via the second electric wire is started, and the first control unit starts the supply of drive current by the second control unit, and then the first motor And starting the supply of the drive current via the first electric wire. The first control unit and the second control unit drive each of the first motor and the second motor by a pulse width signal generated by pulse width modulation,
When the vehicle state detection unit detects that the behavior of the vehicle is unstable, the first control unit sends the second motor to the second motor via the second electric wire by the second control unit. The seat belt device according to claim 1, wherein when the pulse width ON signal is first switched to the OFF signal, the pulse width ON signal is output to the first motor via the first electric wire.

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