WO2020095709A1 - Enrouleur de ceinture de sécurité et dispositif de ceinture de sécurité - Google Patents

Enrouleur de ceinture de sécurité et dispositif de ceinture de sécurité Download PDF

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Publication number
WO2020095709A1
WO2020095709A1 PCT/JP2019/041823 JP2019041823W WO2020095709A1 WO 2020095709 A1 WO2020095709 A1 WO 2020095709A1 JP 2019041823 W JP2019041823 W JP 2019041823W WO 2020095709 A1 WO2020095709 A1 WO 2020095709A1
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WIPO (PCT)
Prior art keywords
current
control circuit
seat belt
motor
switching element
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PCT/JP2019/041823
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English (en)
Japanese (ja)
Inventor
雅人 高尾
Original Assignee
Ｊｏｙｓｏｎ Ｓａｆｅｔｙ Ｓｙｓｔｅｍｓ Ｊａｐａｎ株式会社
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Application filed by Ｊｏｙｓｏｎ Ｓａｆｅｔｙ Ｓｙｓｔｅｍｓ Ｊａｐａｎ株式会社 filed Critical Ｊｏｙｓｏｎ Ｓａｆｅｔｙ Ｓｙｓｔｅｍｓ Ｊａｐａｎ株式会社
Publication of WO2020095709A1 publication Critical patent/WO2020095709A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R22/00—Safety belts or body harnesses in vehicles
    • B60R22/34—Belt retractors, e.g. reels
    • B60R22/46—Reels with means to tension the belt in an emergency by forced winding up
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R22/00—Safety belts or body harnesses in vehicles
    • B60R22/48—Control systems, alarms, or interlock systems, for the correct application of the belt or harness
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P7/00—Arrangements for regulating or controlling the speed or torque of electric DC motors
    • H02P7/06—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current
    • H02P7/18—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power
    • H02P7/24—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices
    • H02P7/28—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices
    • H02P7/285—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only
    • H02P7/29—Arrangements for regulating or controlling the speed or torque of electric DC motors for regulating or controlling an individual dc dynamo-electric motor by varying field or armature current by master control with auxiliary power using discharge tubes or semiconductor devices using semiconductor devices controlling armature supply only using pulse modulation

Definitions

  • the present invention relates to a seat belt retractor and a seat belt device.
  • a motor drive circuit in which, when a counter electromotive force is generated in a motor by an external force applied to a spool that winds up a seat belt, the FET is turned on to cause a current to flow back to the motor through the FET (for example, a patent). Reference 1).
  • the energy absorption load (the load acting on the seat belt) can be adjusted accurately. difficult.
  • the energy absorption load is also referred to as “EA load”.
  • the present disclosure provides a seatbelt retractor and a seatbelt device capable of accurately adjusting the EA load.
  • This disclosure is Spool, A motor for rotating the spool, A switching element connected to the motor, A control circuit for switching the switching element by PWM control so that the motor rotates in a direction in which the seat belt is wound around the spool; A return path that is connected to the switching element and returns a current generated by a back electromotive force of the motor to the motor;
  • a seatbelt retractor and a seatbelt device comprising: a current control circuit that controls the magnitude of the current flowing through the return path.
  • FIG. 6 is a diagram showing an example of a relationship between a rotation speed of a motor when a seat belt is pulled out and a current flowing through a bypass due to a back electromotive force of the motor when the current control circuit shown in FIGS. 3 and 4 is used. It is a figure which shows the 3rd structural example of a current control circuit.
  • FIG. 8 is a diagram showing an example of a relationship between a rotation speed of a motor when a seat belt is pulled out and a current flowing through a bypass due to a back electromotive force of the motor when the current control circuit shown in FIGS. 6 and 7 is used. It is a figure which shows the 5th example of a structure of a current control circuit. It is a figure which shows the 6th example of a structure of a current control circuit.
  • FIG. 11 is a diagram showing an example of the relationship between the rotational speed of the motor when the seat belt is pulled out and the current flowing in the bypass due to the back electromotive force of the motor when the current control circuit shown in FIGS.
  • FIG. 1 is a configuration diagram schematically showing an example of a seat belt device 100.
  • the seat belt device 100 is mounted on a vehicle 13 such as an automobile.
  • the seat belt device 100 includes, for example, a seat belt 2, a shoulder anchor 3, a tongue 4, a buckle 5, and a seat belt retractor (hereinafter, also simply referred to as “retractor”) 10.
  • the retractor 10 includes a seat belt retracting mechanism (hereinafter, also simply referred to as “retracting mechanism”) 6 and a control device 1.
  • the seat belt 2 is an example of a belt-shaped member that restrains the occupant 9 sitting on the seat 11 of the vehicle 13, and is wound around the winding mechanism 6 so as to be pulled out from the winding mechanism 6.
  • One end of the seat belt 2 is connected to the winding mechanism 6, and the other end of the seat belt 2 is fixed to the vehicle body, the pretensioner device, the seat 11, or the like.
  • the seat belt is also called webbing.
  • the shoulder anchor 3 is a guide member that guides the seat belt 2 pulled out from the winding mechanism 6 toward the shoulder of the occupant 9, and is fixed to, for example, the side wall of the passenger compartment or the seat 11.
  • the tongue 4 is a member slidably attached to the seat belt 2 guided by the shoulder anchor 3.
  • the buckle 5 is an example of a member to which the tongue 4 is detachably engaged, and is fixed to, for example, the floor of the vehicle body or the seat 11.
  • the retractor 10 is fixed to, for example, the vehicle body near the seat 11 or the seat 11 itself.
  • the retractor 10 includes a winding mechanism 6 that allows the seat belt 2 to be wound or pulled out, and a control device 1 that controls the operation of the winding mechanism 6.
  • the winding mechanism 6 includes a spool 8 for winding the seat belt 2, a motor 7 for rotating the spool 8, and a power transmission mechanism 17 for transmitting power between the motor 7 and the spool 8.
  • One end of the seat belt 2 is fixed to the spool 8.
  • the motor 7 generates a driving force that rotates the spool 8.
  • the rotation shaft of the motor 7 is connected to the rotation shaft of the spool 8 via the power transmission mechanism 17.
  • the control device 1 controls the winding operation (or both the winding operation and the withdrawing operation) of the seat belt 2 by the winding mechanism 6 by driving the motor 7.
  • the control device 1 includes a drive circuit 14 that drives the motor 7, and a control circuit 15 that controls the drive operation of the drive circuit 14.
  • the drive circuit 14 supplies a drive current for driving the motor 7 to the motor 7 according to at least one control signal (for example, a PWM (pulse width modulation) control signal) supplied from the control circuit 15.
  • a PWM (pulse width modulation) control signal supplied from the control circuit 15.
  • the drive circuit 14 include an H-bridge drive circuit that drives the motor 7 with four switching elements, and a half-bridge drive circuit that drives the motor 7 with two switching elements on the high side and the low side.
  • the drive circuit 14 may be a high-side drive circuit that drives the motor 7 with a high-side switching element, or a low-side drive circuit that drives the motor 7 with a low-side switching element.
  • the form of the drive circuit 14 is not limited to these, but is determined according to the required specifications.
  • the control circuit 15 outputs to the drive circuit 14 at least one control signal (for example, a PWM control signal) that controls the magnitude of the drive current (or the magnitude and direction of the drive current) that drives the motor 7. To do.
  • a control signal for example, a PWM control signal
  • Each function of the control circuit 15 is realized by operating a CPU (Central Processing Unit) according to a program stored in the memory.
  • a specific example of the control circuit 15 is a microcomputer including a CPU and a memory.
  • FIG. 2 is a diagram showing a first configuration example of the drive circuit 14.
  • the drive circuit 14A shown in FIG. 2 is an H-bridge drive circuit that has four switching elements 21, 22, 23, and 24 and is capable of switching the direction of the drive current supplied to the motor 7.
  • the motor 7 contains a coil connected between the first terminal 7a and the second terminal 7b.
  • the drive circuit 14A has a first connection point 18 connected to the first terminal 7a of the motor 7 and a second connection point 12 connected to the second terminal 7b of the motor 7, Drive current is passed through the first connection point 18 and the second connection point 12.
  • the first connection point 18 is an intermediate node where the switching element 21 and the switching element 22 are connected
  • the second connection point 12 is an intermediate node where the switching element 23 and the switching element 24 are connected.
  • the drive circuit 14A is connected between the power supply VB and the ground (GND), and the high-side switching elements 21 and 23 connected to the power supply VB side with respect to the motor 7 and the ground side with respect to the motor 7. And low side switching elements 22 and 24 connected to.
  • the switching elements 21, 22, 23, and 24 are semiconductor elements that perform on / off operations, and may be voltage-controlled transistors or current-controlled bipolar transistors. Voltage-controlled transistors include IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).
  • FIG. 2 illustrates a mode in which the switching elements 21, 22, 23 and 24 are N-channel type MOSFETs.
  • the switching element 21 is an example of a first high side switching element connected to the first terminal 7a.
  • the switching element 21 includes an electrode (drain or collector) connected to the power supply VB side, an electrode (source or emitter) connected to the first terminal 7a via the first connection point 18, and a control circuit 15. It is a high side arm having an electrode (gate or base) connected thereto.
  • the switching element 22 is an example of a first low-side switching element connected to the first terminal 7a.
  • the switching element 22 is connected to the electrode (source or emitter) connected to the ground side, the electrode (drain or collector) connected to the first terminal 7 a via the first connection point 18, and the control circuit 15. And a low side arm having an electrode (gate or base) to be driven.
  • the switching element 23 is an example of a second high side switching element connected to the second terminal 7b.
  • the switching element 23 includes an electrode (drain or collector) connected to the power supply VB side, an electrode (source or emitter) connected to the second terminal 7b through the second connection point 12, and a control circuit 15. It is a high side arm having an electrode (gate or base) connected thereto.
  • the switching element 24 is an example of a second low side switching element connected to the second terminal 7b.
  • the switching element 24 is connected to the electrode (source or emitter) connected to the ground side, the electrode (drain or collector) connected to the second terminal 7b through the second connection point 12, and the control circuit 15.
  • the diodes 31, 32, 33, 34 may be body diodes of the corresponding switching elements 21, 22, 23, 24, or are additionally connected in parallel to the corresponding switching elements 21, 22, 23, 24.
  • a rectifying element may be used.
  • the current measuring circuit 16 is a current measuring unit that measures the current flowing through the drive circuit 14A and outputs the measurement result to the control circuit 15.
  • the current measuring circuit 16 measures the magnitude of the current flowing through the drive circuit 14A by, for example, a resistor inserted in series in the current path between the low-side switching elements 22 and 24 of the drive circuit 14A and the ground.
  • the current path between the switching elements 22 and 24 and the ground is a current path that connects electrodes (sources or emitters) connected to the ground side of the switching elements 22 and 24 (specifically, returns to the motor 7).
  • the meaning of a path through which a current I EA described later passes) is included.
  • the current measuring circuit 16 determines the magnitude of the current flowing through the drive circuit 14A by, for example, a resistor inserted in series in the current path between the high-side switching elements 21 and 23 of the drive circuit 14A and the power supply VB. You may measure.
  • the current measurement method is not limited to these.
  • the control circuit 15 is a drive control unit that drives the four switching elements 21, 22, 23, 24 forming the drive circuit 14A by using the current measurement result of the current measurement circuit 16 and the like.
  • the control circuit 15 drives the motor 7 to rotate (forward rotation) in the forward rotation direction corresponding to the winding direction of the seat belt 2. It controls each switching element of the circuit 14A. For example, in the winding mode in which the motor 7 rotates forward, the control circuit 15 turns on / off (switches) the switching element 22 by PWM control with a predetermined duty ratio, constantly turns off the switching elements 21 and 24, and switches the switching element. 23 is always turned on. At this time, the control circuit 15 may turn on the switching element 21 when the switching element 22 is off, in order to suppress heat generation due to the return current when the switching element 22 is off.
  • the drive circuit 14A can rotate the motor 7 (normal rotation) in the direction of rotating the spool 8 in the winding direction of the seat belt 2 (normal rotation direction). it can.
  • the rotation shaft of the motor 7 rotates in the forward direction
  • the drive force of the forward rotation is transmitted to the spool 8 by the power transmission mechanism 17.
  • the spool 8 rotates in the direction in which the seat belt 2 is wound, so that the seat belt 2 is wound around the spool 8.
  • the control circuit 15 drives the drive circuit 14A so that the motor 7 rotates in the reverse direction corresponding to the pull-out direction of the seat belt 2 (reverse rotation).
  • the control circuit 15 turns on / off (switches) the switching element 24 by PWM control with a predetermined duty ratio to constantly turn off the switching elements 22 and 23, and the switching element 21. Is always on.
  • the control circuit 15 may turn on the switching element 23 when the switching element 24 is off in order to suppress heat generation due to the return current when the switching element 24 is off.
  • the drive circuit 14A can rotate the motor 7 (reverse rotation) in the direction of rotating the spool 8 in the direction of withdrawing the seat belt 2 (reverse rotation).
  • the rotation shaft of the motor 7 rotates in the reverse direction
  • the driving force of the reverse rotation is transmitted to the spool 8 by the power transmission mechanism 17.
  • the spool 8 rotates in the direction in which the seat belt 2 is pulled out, so that the seat belt 2 is pulled out from the spool 8.
  • the drive circuit 14A includes a current adjustment circuit 44 connected in parallel with the switching element 22.
  • a current adjustment circuit 44 When the rotating shaft of the motor 7 and the rotating shaft of the spool 8 are connected by the power transmission mechanism 17, when the motor 7 is rotated by an external force applied to the spool 8, a counter electromotive force is generated in the motor 7.
  • the current adjusting circuit 44 causes the current I EA generated by this back electromotive force to flow back to the motor 7, thereby suppressing the rotation of the motor 7 and applying the brake.
  • the vehicle-mounted computer outside the retractor 10 transmits a command signal for starting the restraint force control of the seat belt 2 on the occupant 9.
  • the control circuit 15 receives a command signal from an in-vehicle computer outside the retractor 10 and the like, and the seat belt 2 The restraint force control for the occupant 9 is started.
  • the control circuit 15 prepares for an impact at the time of a collision, so that the motor 7 rotates (normal rotation) in the normal rotation direction corresponding to the winding direction of the seat belt 2 so that the drive circuit 14A operates. Control each switching element.
  • the rotation shaft of the motor 7 rotates in the forward direction
  • the drive force of the forward rotation is transmitted to the spool 8 by the power transmission mechanism 17.
  • the spool 8 rotates in the direction in which the seat belt 2 is wound, so that the seat belt 2 is wound around the spool 8.
  • the restraint force on the occupant 9 by the seat belt 2 increases.
  • the seat belt 2 is pulled out from the spool 8 by the inertial force of the occupant 9 toward the front of the vehicle.
  • the rotational force is transmitted to the rotation shaft of the motor 7 by the power transmission mechanism 17.
  • the rotating shaft of the motor 7 is rotated in the reverse direction, so that a counter electromotive force is generated in the motor 7. Due to the generation of this counter electromotive force, the potential of the first terminal 7a becomes relatively higher than the potential of the second terminal 7b (in other words, the potential of the second terminal 7b is higher than the potential of the first terminal 7a. Is also relatively low).
  • the control circuit 15 when the control circuit 15 receives the command signal indicating that the collision of the vehicle 13 is detected, the control circuit 15 rotates the motor 7 in the forward rotation direction in which the spool 8 is rotated in the winding direction of the seat belt 2, and then, The bypass 45 is switched from the disconnected state to the connected state.
  • the bypass 45 is a current path that is connected in parallel to both ends of the switching element 22 and causes the current I EA generated by the back electromotive force of the motor 7 to flow back to the motor 7.
  • the bypass 45 is a part of a return path for returning the current I EA to the motor 7.
  • the control circuit 15 may turn on the switching element 24 so that the current I EA flows through the switching element 24 instead of the diode 34.
  • control circuit 15 causes the current I EA generated by the back electromotive force to flow back to the motor 7 via the bypass 45, so that the motor 7 rotates in the reverse direction in which the spool 8 is rotated in the pulling direction of the seat belt 2. Can be suppressed. As a result, it becomes possible to absorb the collision energy that acts on the occupant 9 during a vehicle collision.
  • the control circuit 15 when the control circuit 15 receives a command signal indicating that the collision of the vehicle 13 is detected, the control circuit 15 operates the changeover switch 40 that is inserted in series with the detour 45 to remove the detour 45 from the cutoff state. Switch to the connected state.
  • the changeover switch 40 is, for example, a switching element such as a MOSFET.
  • the current adjustment circuit 44 inserted in series in the bypass circuit 45 has, for example, a configuration in which the changeover switch 40 and the current control circuit 41 are connected in series.
  • the changeover switch 40 and the current control circuit 41 are inserted in the detour 45 in series.
  • the positions where the changeover switch 40 and the current control circuit 41 are inserted in series in the bypass 45 may be replaced with each other.
  • the current control circuit 41 controls the magnitude of the current I EA flowing through the bypass 45.
  • the force that suppresses the rotation of the motor 7 in the reverse rotation direction that rotates the spool 8 in the pull-out direction of the seat belt 2 changes, so the EA load (the load acting on the seat belt 2 is changed. ) Also changes.
  • the EA load increases as the current I EA increases. Therefore, the current control circuit 41 controls the magnitude of the current I EA , whereby the EA load can be adjusted with high accuracy.
  • the current control circuit 41 may have a configuration in which the magnitude of the current I EA flowing through the detour 45 is limited so as not to exceed a predetermined upper limit value (hereinafter, also referred to as upper limit current I U ). With such a configuration, the EA load can be limited to the upper limit load F U or less corresponding to the upper limit current I U , so that the EA load can be prevented from becoming too large.
  • a predetermined upper limit value hereinafter, also referred to as upper limit current I U .
  • the current control circuit 41 may have a configuration for adjusting the upper limit current I U according to an adjustment signal supplied from the outside.
  • the upper limit load F U can be adjusted by adjusting the upper limit current I U.
  • the control circuit 15 supplies the current control circuit 41 with an adjustment signal for adjusting the upper limit current I U based on the physique information such as the weight of the occupant 9. Accordingly, the upper limit current I U and the upper limit load F U suitable for the physique of the occupant 9 can be set. For example, as the weight of the occupant 9 becomes heavier, the upper limit current I U and the upper limit load F U are set higher.
  • FIG. 3 is a diagram showing a first configuration example of the current control circuit 41.
  • the current control circuit 41A shown in FIG. 3 is connected in series between the first node 42 and the second node 43 on the bypass 45.
  • the current control circuit 41A is a current limiting circuit that limits the magnitude of the current I EA flowing in the bypass 45 so as not to exceed a predetermined upper limit current I U.
  • the current control circuit 41A has resistors 51, 52, 53, npn-type bipolar transistors 54, 55, and zener diodes 56, 57.
  • the base current flowing from the power supply VB to the base of the bipolar transistor 54 via the resistor 51 causes the current I EA to flow from the collector of the bipolar transistor 54 to the emitter.
  • the resistor 53 is connected to the emitter of the bipolar transistor 54 so as to be inserted in the detour 45 in series.
  • the collector current of the bipolar transistor 55 flows.
  • the base current flowing from the power supply VB to the base of the bipolar transistor 54 via the resistor 51 decreases.
  • the current I EA is limited so as not to exceed the upper limit current I U.
  • the upper limit current I U is set by “(R53 / (R52 + R53)) ⁇ V BE55 ”.
  • R52 and R53 represent resistance values of the resistors 52 and 53, respectively.
  • V BE55 represents the base-emitter voltage of the bipolar transistor 55, with an upper limit of approximately 0.6 volts.
  • the current control circuit 41A detects the magnitude of the current I EA flowing through the bypass 45 by using the resistor 53, and controls the magnitude of the current I EA flowing through the bypass 45 based on the detection result. To do. By feeding back the detection result, the current control circuit 41A limits the magnitude of the current I EA flowing through the bypass 45 so as not to exceed the upper limit current I U.
  • the Zener diode 56 is an element that protects the base-emitter of the bipolar transistor 54 from overvoltage.
  • the Zener diode 57 is an element that protects the base-emitter of the bipolar transistor 55 from overvoltage.
  • FIG. 4 is a diagram showing a second configuration example of the current control circuit 41.
  • the current control circuit 41B shown in FIG. 4 is connected in series between the first node 42 and the second node 43 on the bypass 45.
  • the current control circuit 41B is a current limiting circuit that limits the magnitude of the current I EA flowing through the bypass 45 so as not to exceed a predetermined upper limit current I U.
  • the current control circuit 41B also has a configuration of adjusting the upper limit current I U according to an adjustment signal S U supplied from the outside.
  • the current control circuit 41B includes resistors 61 to 65, an npn-type bipolar transistor 66, a Zener diode 67, and a comparator 68.
  • the bypass circuit 45 When the bypass circuit 45 is switched from the cut-off state to the connection state, the base current flowing from the power supply VB to the base of the bipolar transistor 66 via the resistor 63 causes the current I EA to flow from the collector of the bipolar transistor 66 to the emitter.
  • the resistor 65 is connected to the emitter of the bipolar transistor 66 so as to be inserted in series with the bypass 45.
  • the comparator 68 sinks current from its output terminal.
  • the current is absorbed in the output terminal of the comparator 68, the base current flowing from the power supply VB to the base of the bipolar transistor 66 via the resistor 63 decreases.
  • the current I EA is limited so as not to exceed the upper limit current I U.
  • Adjustment signal S U to adjust the upper limit current I U, via a resistor 61, is input to the non-inverting input terminal of the comparator 68.
  • the voltage of the non-inverting input terminal of the comparator 68 changes according to the analog voltage value of the adjustment signal S U. Therefore, the upper limit current I U is adjusted to a current value according to the analog voltage value of the adjustment signal S U.
  • the adjustment signal S U may be supplied from the control circuit 15 or may be supplied from a circuit or a device different from the control circuit 15.
  • the current control circuit 41B detects the magnitude of the current I EA flowing in the bypass 45 by using the resistor 65, and controls the magnitude of the current I EA flowing in the bypass 45 based on the detection result. To do.
  • the current control circuit 41B limits the magnitude of the current I EA flowing through the bypass 45 so as not to exceed the upper limit current I U by feeding back the detection result.
  • the Zener diode 67 is an element that protects the base-emitter of the bipolar transistor 66 from overvoltage.
  • FIG. 5 shows the rotation speed of the motor 7 when the seat belt 2 is pulled out and the current flowing through the bypass 45 due to the counter electromotive force of the motor 7 when the current control circuits 41A and 41B shown in FIGS. It is a figure which shows an example of the relationship of.
  • the detour 45 When the detour 45 is in the cutoff state (open state), the current I EA does not flow in the detour 45.
  • the detour 45 is in the connected state (short-circuited state)
  • the higher the speed at which the motor 7 rotates in the reverse rotation direction corresponding to the direction in which the seat belt 2 is pulled out the larger the current I EA flowing through the detour 45 becomes. , EA load also increases.
  • the current I EA larger than the predetermined upper limit current I U does not flow like the current limits a and b shown in FIG.
  • the EA load can be limited to the upper limit load F U or less corresponding to U.
  • the upper limit current I U can be adjusted to a desired current value according to the adjustment signal S U.
  • the current control circuit 41 shown in FIG. 2 prevents the current I EA from flowing into the bypass 45 until the counter electromotive force of the motor 7 exceeds a predetermined lower limit value (hereinafter, also referred to as lower limit voltage VL ).
  • the configuration may be limited to. With such a configuration, the efficiency of the current I EA flowing back to the motor 7 decreases with respect to the rotation speed of the motor 7, so that the relationship between the rotation speed of the motor 7 and the EA load (more specifically, the motor 7 The inclination characteristic of the EA load with respect to the rotation speed) can be adjusted as shown in FIG. That is, the inclination characteristic of the EA load with respect to the rotation speed of the motor 7 can be made gentle.
  • the current control circuit 41 may have a configuration of adjusting the lower limit voltage VL according to an adjustment signal supplied from the outside.
  • the control circuit 15 supplies the current control circuit 41 with an adjustment signal for adjusting the lower limit voltage VL based on the physique information such as the weight of the occupant 9.
  • the relationship between the rotation speed of the motor 7 and the EA load can be set to a characteristic suitable for the physique of the occupant 9. For example, the lower the weight of the occupant 9, the higher the lower limit voltage VL is set.
  • FIG. 6 is a diagram showing a third configuration example of the current control circuit 41.
  • the current control circuit 41C shown in FIG. 6 is connected in series between the first node 42 and the second node 43 on the bypass 45.
  • the current control circuit 41C is a current limiting circuit that limits the current I EA from flowing into the bypass 45 until the counter electromotive force generated in the motor 7 exceeds a predetermined lower limit voltage V L.
  • the current control circuit 41C has resistors 71 and 72, an npn-type bipolar transistor 73, and a Zener diode 74.
  • the bipolar transistor 73 When the counter electromotive force of the motor 7 rises and the base-emitter voltage of the bipolar transistor 73 becomes larger than about 0.6 volt, the bipolar transistor 73 is turned on. As a result, the current I EA flowing between the collector and the emitter of the bipolar transistor 73 rapidly increases from substantially zero. That is, the current I EA is limited so as not to flow to the bypass 45 until the counter electromotive force generated in the motor 7 exceeds the predetermined lower limit voltage V L.
  • the current control circuit 41C detects the magnitude of the back electromotive force of the motor 7 using the resistors 71 and 72, and controls the magnitude of the current I EA flowing through the bypass 45 based on the detection result. To do.
  • the Zener diode 74 is an element that protects the base-emitter of the bipolar transistor 73 from overvoltage.
  • FIG. 7 is a diagram showing a fourth configuration example of the current control circuit 41.
  • the current control circuit 41D shown in FIG. 7 is connected in series between the first node 42 and the second node 43 on the bypass 45.
  • the current control circuit 41D is a current limiting circuit that limits the current I EA from flowing into the bypass 45 until the counter electromotive force generated in the motor 7 exceeds a predetermined lower limit voltage V L.
  • the current control circuit 41D also has a configuration of adjusting the lower limit voltage V L according to an adjustment signal S L supplied from the outside.
  • the current control circuit 41D has resistors 81 to 85, an npn-type bipolar transistor 86, a Zener diode 87, and a comparator 88.
  • Adjustment signal S L to adjust the lower limit voltage V L, via a resistor 81, it is input to the inverting input terminal of the comparator 88.
  • the voltage at the inverting input terminal of the comparator 88 changes according to the analog voltage value of the adjustment signal S L. Therefore, the lower limit voltage V L is adjusted to a voltage value according to the analog voltage value of the adjustment signal S L.
  • the adjustment signal S L may be supplied from the control circuit 15 or may be supplied from a circuit or a device different from the control circuit 15.
  • the current control circuit 41D detects the magnitude of the back electromotive force of the motor 7 by using the resistors 84 and 85, and controls the magnitude of the current I EA flowing through the bypass 45 based on the detection result. To do.
  • the Zener diode 87 is an element that protects the base-emitter of the bipolar transistor 86 from overvoltage.
  • FIG. 8 shows the rotation speed of the motor 7 when the seat belt 2 is pulled out and the current flowing in the bypass 45 by the counter electromotive force of the motor 7 when the current control circuits 41C and 41D shown in FIGS. It is a figure which shows an example of the relationship of.
  • the current control circuits 41C and 41D shown in FIGS. 6 and 7 even when the rotation speed of the motor 7 increases, the counter electromotive force exceeds the lower limit voltage V L, as in the current limits c and d shown in FIG. , The current I EA hardly flows. Therefore, the relationship between the rotation speed of the motor 7 and the EA load (the inclination characteristic of the EA load with respect to the rotation speed of the motor 7) can be adjusted to a gentle characteristic. Further, according to the current control circuit 41D shown in FIG. 7, the lower limit voltage V L can be adjusted to a desired voltage value according to the adjustment signal S L.
  • FIG. 9 is a diagram showing a fifth configuration example of the current control circuit 41.
  • the current control circuit 41E shown in FIG. 9 is a circuit in which the current control circuit 41A shown in FIG. 3 and the current control circuit 41C shown in FIG. 6 are combined, and the upper limit current limiting function and the current control circuit 41C of the current control circuit 41A are included. Has a lower limit voltage limiting function. Therefore, the current control circuit 41E detects the magnitude of the current I EA flowing in the bypass 45 by using the resistor 53, the magnitude of the counter electromotive force of the motor 7 by using the resistors 71 and 72, and The magnitude of the current I EA flowing through the bypass 45 is controlled based on the detection result.
  • FIG. 10 is a diagram showing a sixth configuration example of the current control circuit 41.
  • the current control circuit 41F shown in FIG. 10 is a circuit in which the current control circuit 41B shown in FIG. 4 and the current control circuit 41D shown in FIG. 7 are combined, and the upper limit current adjustment function and the current control circuit 41D of the current control circuit 41B are included. Has a lower limit voltage adjusting function. Therefore, the current control circuit 41F detects the magnitude of the current I EA flowing in the bypass 45 by using the resistor 65 and the magnitude of the counter electromotive force of the motor 7 by using the resistors 84 and 85, and detects those magnitudes. The magnitude of the current I EA flowing through the bypass 45 is controlled based on the detection result. Then, the current control circuit 41F adjusts the upper limit current I U according to the adjustment signal S U , and adjusts the lower limit voltage V L according to the adjustment signal S L.
  • FIG. 11 shows the rotation speed of the motor 7 when the seat belt 2 is pulled out and the current flowing in the bypass 45 due to the counter electromotive force of the motor 7 when the current control circuits 41E and 41F shown in FIGS.
  • It is a figure which shows an example of the relationship of. 9 and 10 shows a current control circuit 41E, according to 41F, as current limiting e, f shown in FIG. 11, since not flow a large current I EA than a predetermined upper limit current I U, the upper limit current I U
  • the EA load can be limited below the corresponding upper limit load F U. Further, according to the current control circuits 41E and 41F shown in FIGS.
  • the relationship between the rotation speed of the motor 7 and the EA load (the inclination characteristic of the EA load with respect to the rotation speed of the motor 7) can be adjusted to a gentle characteristic.
  • the upper limit current I U can be adjusted to a desired current value according to the adjustment signal S U
  • the lower limit voltage V L can be adjusted to a desired voltage value according to the adjustment signal S L. Can be adjusted to.
  • FIG. 12 is a diagram showing a second configuration example of the drive circuit 14. The description of the same points as the first configuration example will be omitted.
  • the drive circuit 14B shown in FIG. 12 is a low-side drive circuit that has a low-side switching element 25 and can supply a drive current to the motor 7 in only one direction.
  • the drive circuit 14B is used, for example, when it is not necessary to rotate the motor 7 in the reverse rotation direction corresponding to the withdrawal direction of the seat belt 2, and rotates the motor 7 in the normal rotation direction corresponding to the winding direction of the seat belt 2.
  • the drive current to be supplied can be supplied to the motor 7.
  • the drive circuit 14B is connected between the power supply VB and the ground (GND), and includes a low-side switching element 25 connected to the ground side with respect to the motor 7.
  • the switching element 25 includes an electrode (drain or collector) connected to the first terminal 7a, an electrode (source or emitter) connected to the ground side, and an electrode (gate or base) connected to the control circuit 15. It is a low side arm having.
  • the second terminal 7b is connected to the power supply VB.
  • the diode 35 may be a body diode of the switching element 25 or a rectifying element additionally connected in parallel with the switching element 25.
  • the control circuit 15 drives the motor 7 to rotate (forward rotation) in the forward rotation direction corresponding to the winding direction of the seat belt 2. It controls the switching element 25 of the circuit 14B. For example, the control circuit 15 turns on / off (switches) the switching element 25 by PWM control with a predetermined duty ratio in the winding mode in which the motor 7 rotates forward.
  • the drive circuit 14B can rotate the motor 7 (normal rotation) in the direction in which the spool 8 is rotated in the winding direction of the seat belt 2 (normal rotation direction). it can.
  • the rotation shaft of the motor 7 rotates in the forward direction
  • the drive force of the forward rotation is transmitted to the spool 8 by the power transmission mechanism 17.
  • the spool 8 rotates in the direction in which the seat belt 2 is wound, so that the seat belt 2 is wound around the spool 8.
  • the drive circuit 14B includes a current adjustment circuit 44 connected in parallel with the switching element 25.
  • the potential of the first terminal 7a becomes relatively higher than the potential of the second terminal 7b due to the generation of the counter electromotive force (in other words, the potential of the second terminal 7b becomes the first potential). It becomes relatively lower than the potential of the terminal 7a).
  • the control circuit 15 when the control circuit 15 receives the command signal indicating that the collision of the vehicle 13 is detected, the control circuit 15 rotates the motor 7 in the forward rotation direction in which the spool 8 is rotated in the winding direction of the seat belt 2, and then, The bypass 45 is switched from the disconnected state to the connected state.
  • the bypass 45 is a current path that is connected in parallel to both ends of the switching element 25 and causes the current I EA generated by the back electromotive force of the motor 7 to flow back to the motor 7.
  • the bypass 45 is a part of a return path for returning the current I EA to the motor 7.
  • the current I EA generated by the counter electromotive force flows back in the normal path of the first terminal 7a, the bypass circuit 45, the ground GND, the power supply VB, and the second terminal 7b. At this time, the current I EA is limited by the current control circuit 41 so as not to exceed the upper limit current I U.
  • control circuit 15 causes the current I EA generated by the back electromotive force to flow back to the motor 7 via the bypass 45, so that the motor 7 rotates in the reverse direction in which the spool 8 is rotated in the pulling direction of the seat belt 2. Can be suppressed. As a result, it becomes possible to absorb the collision energy that acts on the occupant 9 during a vehicle collision. Further, the current control circuit 41 controls the magnitude of the current I EA , so that the EA load can be adjusted with high accuracy.
  • FIG. 13 is a diagram showing a third configuration example of the drive circuit 14. The description of the same points as those of the above configuration example will be omitted.
  • the drive circuit 14C shown in FIG. 13 is an H-bridge drive circuit that has four switching elements 21, 22, 23, and 24 and is capable of switching the direction of the drive current supplied to the motor 7.
  • the drive circuit 14C has a configuration in which the current control circuit 41G is integrated with the switching element 22.
  • the current control circuit 41G is an example of the current control circuit 41 described above.
  • the current control circuit 41G controls the magnitude of the current I EA flowing through the return path 46 by repeating switching (on / off) of the switching element 22 in accordance with the control signal A supplied from the control circuit 15.
  • the return path 46 is a current path that is connected to the switching element 22 and causes the current I EA generated by the counter electromotive force of the motor 7 to return to the motor 7.
  • the current control circuit 41G controls the magnitude of the current I EA , whereby the EA load can be adjusted with high accuracy.
  • control circuit 15 when the control circuit 15 receives a command signal indicating that a collision of the vehicle 13 has been detected, the control circuit 15 controls the magnitude of the current I EA flowing through the return path 46 (for example, a PWM control signal). Is output.
  • the current control circuit 41G may have the above-described configuration that controls the magnitude of the current I EA by using at least one of the upper limit current I U and the lower limit voltage V L. Further, the current control circuit 41G may have the above-described configuration that adjusts at least one of the upper limit current I U and the lower limit voltage V L according to the adjustment signal supplied from the outside.
  • FIG. 14 is a diagram showing a configuration example of the current control circuit 41G.
  • the current control circuit 41G is connected in series between the first node 42 and the second node 43 on the return path 46.
  • the current control circuit 41G is a current limiting circuit that limits the magnitude of the current I EA flowing in the return path 46 so as not to exceed a predetermined upper limit current I U.
  • the current control circuit 41G also has a configuration of adjusting the upper limit current I U according to an adjustment signal S U supplied from the outside.
  • the current control circuit 41G includes resistors 61 to 65, a low side switching element 22, a Zener diode 67, and a comparator 68.
  • the current control circuit 41G repeats switching (ON / OFF) of the switching element 22 according to the control signal A supplied from the control circuit 15 when the collision of the vehicle 13 is detected.
  • the current I EA flows through the return path 46 while the flow of the switching element 22 is limited by the current control circuit 41G being repeated, so that the magnitude of the current I EA flowing through the return path 46 can be controlled. ..
  • the control signal A is supplied to the gate of the switching element 22 via the resistor 63.
  • the switching element 22 is repeatedly turned on and off by the control signal A, so that the current I EA flows from the drain to the source of the switching element 22.
  • the resistor 65 is connected to the source of the switching element 22 so as to be inserted in the return path 46 in series. When the current I EA rises, the voltage across the resistor 65 rises.
  • the comparator 68 sinks current from its output terminal.
  • the gate voltage of the switching element 22 drops.
  • the current I EA is limited so as not to exceed the upper limit current I U.
  • the control circuit 15 turns on / off the switching element 23 by PWM control with a predetermined duty ratio in the winding mode in which the motor 7 rotates in the forward direction, constantly turns off the switching elements 21 and 24, and performs switching.
  • the element 22 may be always turned on.
  • the control circuit 15 may turn on the switching element 24 when the switching element 23 is turned off in order to suppress heat generation due to the return current when the switching element 23 is turned off.
  • the bypass 45 in which the current adjusting circuit 44 is inserted in series is connected in parallel to the switching element 23.
  • Control Device 2 Seat Belt 6 Seat Belt Winding Mechanism 7 Motor 8 Spool 10 Seat Belt Retractor 14, 14A, 14B, 14C Drive Circuit 15 Control Circuit 17 Power Transmission Mechanism 21-25 Switching Element 40 Changeover Switch 41, 41A-41G Current Control circuit 44 Current adjusting circuit 45 Detour 46 Return path 100 Seat belt device

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Power Engineering (AREA)
  • Automation & Control Theory (AREA)
  • Automotive Seat Belt Assembly (AREA)
  • Control Of Direct Current Motors (AREA)

Abstract

L'invention concerne un enrouleur de ceinture de sécurité et un dispositif de ceinture de sécurité. La présente invention comprend : une bobine ; un moteur pour faire tourner la bobine ; un élément de commutation connecté au moteur ; un circuit de commande qui commute l'élément de commutation par l'intermédiaire d'une commande PWM de telle sorte que le moteur tourne dans une direction dans laquelle une ceinture de sécurité est enroulée autour de la bobine ; un trajet de recirculation pour faire recirculer, vers le moteur, un courant produit par la force contre-électromotrice du moteur ; et un circuit de commande de courant pour commander l'amplitude du courant circulant vers le trajet de recirculation.
PCT/JP2019/041823 2018-11-07 2019-10-25 Enrouleur de ceinture de sécurité et dispositif de ceinture de sécurité WO2020095709A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018-209972 2018-11-07
JP2018209972A JP2020075612A (ja) 2018-11-07 2018-11-07 シートベルトリトラクタ及びシートベルト装置

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WO2020095709A1 true WO2020095709A1 (fr) 2020-05-14

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Application Number Title Priority Date Filing Date
PCT/JP2019/041823 WO2020095709A1 (fr) 2018-11-07 2019-10-25 Enrouleur de ceinture de sécurité et dispositif de ceinture de sécurité

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JP (1) JP2020075612A (fr)
WO (1) WO2020095709A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009262811A (ja) * 2008-04-25 2009-11-12 Tokai Rika Co Ltd ウエビング巻取装置
JP2011111035A (ja) * 2009-11-26 2011-06-09 Denso Corp モータ駆動回路
JP2011183873A (ja) * 2010-03-05 2011-09-22 Tokai Rika Co Ltd ウエビング巻取装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009262811A (ja) * 2008-04-25 2009-11-12 Tokai Rika Co Ltd ウエビング巻取装置
JP2011111035A (ja) * 2009-11-26 2011-06-09 Denso Corp モータ駆動回路
JP2011183873A (ja) * 2010-03-05 2011-09-22 Tokai Rika Co Ltd ウエビング巻取装置

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