JP2015024759A - Seat belt device - Google Patents

Abstract

A clutch sound when an electric motor is operated and an impact when the clutch is engaged are reduced to reduce discomfort and discomfort to an occupant. In a seat belt device, a control device (control unit) 31 supplies a first current to the electric motor in a first section (rush current section A) in which the stopped electric motor is driven. In the second section (initial drive current section B) following the first section, a second current smaller than the first current is supplied to the electric motor 23 to continue the rotation of the electric motor 23. [Selection] Figure 5

Description

  The present invention relates to a seat belt device.

  For example, Patent Document 1 proposes a restraint device that operates a clutch accurately and reduces noise generated due to the operation of the clutch.

  Specifically, in Patent Document 1, as shown in FIG. 7 of the same document, when the connection between the electric motor and the spool is released, the value of the drive voltage is increased at the start of the electric motor and the rotation is started. After that, a technique for setting the minimum size required to maintain the rotation is disclosed. Thereby, the sound emitted from the electric motor can be reduced without unnecessarily increasing the rotational speed of the electric motor.

JP 2013-43586 A

  However, according to the technique disclosed in Patent Document 1, the electric motor may move more than expected at the start due to the specifications of the electric motor, the aging of the electric motor, etc., and the electric motor side gear and the retractor side gear still remain. Occasionally, the passenger may feel uncomfortable or uncomfortable due to the impact or operating noise generated when the clutch is engaged.

  The present invention has been made in order to solve the above-described problems, and reduces the feeling of discomfort and discomfort to the occupant by reducing the clutch sound when the electric motor is operated and the impact when the clutch is engaged. An object is to provide a belt device.

  In order to solve the above-described problems, the present invention provides a webbing reel capable of winding a webbing, an electric motor connected to the webbing reel via a clutch, and rotation or stop of the electric motor according to the state of the vehicle. A control unit that controls the seat belt device, wherein the control unit supplies a first current to the electric motor in a first section for driving the stopped electric motor; In the second section following the first section, the electric motor is supplied with a second current smaller than the first current to continue the rotation of the electric motor. In the first section, the electric motor A voltage signal with a first duty is supplied, and the electric motor is controlled so that the second current becomes a command current value in the second section.

  In the present invention, the control unit supplies a voltage signal with a second duty higher than the first duty to the electric motor in a third section following the second section, so that the third of the electric motor is supplied. The current is gradually increased.

  In the present invention, when the vehicle state detection unit detects wearing of a buckle, the control unit is larger than the second current supplied in the second section in the fourth section following the third section. The webbing is loosened with a fourth current.

  In the present invention, a vehicle state detection unit that detects the state of the vehicle is provided, and the control unit detects the acceleration that is greater than or equal to a predetermined value in the fourth section after the third section has elapsed. The webbing is held and controlled by a fourth current larger than the current supplied in the second section.

  In the present invention, the first section is shorter than the second section.

  In the present invention, the second section is equal to or larger than the third section.

  In the present invention, a vehicle state detection unit that detects a vehicle state is provided, and the control unit detects the emergency state of the vehicle when the vehicle state detection unit detects the emergency state of the vehicle at least in the first section. A maximum allowable current larger than the first current is supplied instead of one current.

  According to the present invention, it is possible to provide a seat belt device that reduces clutch sound when the electric motor is operated and impact when the clutch is engaged, thereby reducing discomfort and discomfort to the occupant.

It is a side view which shows the mounting state of the seatbelt apparatus of this embodiment. It is a figure which shows the principal part structure of the retractor of FIG. It is a figure which shows schematic structure of the power transmission system of FIG. FIG. 4 is a partially enlarged view of the power transmission system of FIG. 3. It is a block diagram which shows the structure of the control apparatus of FIG. FIG. 3 is a timing chart showing the operation of the control unit in FIG. 2. It is a flowchart which shows operation | movement of the control part of FIG.

  Hereinafter, the seat belt device of the present embodiment will be described in detail with reference to the drawings.

(Configuration of the embodiment)
In FIG. 1, a seat belt device 10 according to this embodiment includes a webbing 13 that restrains the body of an occupant 11 to a seat 12. The webbing 13 includes a belt portion 13 a that restrains the upper body of the occupant 11 and a belt portion 13 b that restrains the waist of the occupant 11.

  One end of the belt portion 13b is fixed to the vehicle body portion at the lower part of the passenger compartment by an anchor plate 14. The belt portion 13 a is folded back by a through anchor 15 provided at a location near the shoulder of the occupant 11, and its end is connected to the webbing reel 22 of the retractor 16. A tongue plate 17 is attached to the other common end (folded portion) of the webbing 13. The tongue plate 17 is detachably attached to a buckle 18 fixed to the lower edge of the seat 12. The buckle 18 is provided with a buckle switch 19 that detects the connection of the tongue plate 17.

  FIG. 2 schematically shows a main configuration of the seat belt retractor 16. The retractor 16 includes a webbing reel (spindle) 22 that is rotatably provided in the housing 21, and an electric motor 23 that rotationally drives the webbing reel 22. The webbing reel 22 is coupled to the end of the belt part 13 a of the webbing 13, and the belt part 13 a is taken up by the webbing reel 22.

  A winding spring 202 is attached to the left end of the shaft 22a of the webbing reel 22 in FIG. Further, the shaft 22 a of the webbing reel 22 is connected to the drive shaft 23 a of the electric motor 23 through a power transmission mechanism (gear mechanism) 24. The webbing reel 22 is rotated by an electric motor 23 via a power transmission mechanism 24.

  The operation of the retractor 16 is controlled by the control device 30. The control device 30 controls the operation of the retractor 16 by controlling the amount of drive current supplied to the electric motor 23. The retractor 16 controlled by the control device 30 is configured as an electric pretensioner for maintaining the posture of the occupant 11. The occupant 11 riding on the seat 12 is protected and restrained by the webbing 13 in the event of an emergency of the vehicle or when the running state is unstable, and changes in posture and position are suppressed, and the desired safe state is maintained.

  Further, in the seat belt retractor 16, the other end (the right end in FIG. 2) of the webbing reel 22 on the opposite side of the shaft 22a has a sharp portion of the belt portion 13a of the webbing 13 when an emergency situation of vehicle travel occurs. A lock mechanism 100 for preventing the drawer is attached. The case where an emergency situation of vehicle travel occurs is a case where a predetermined inclination acts on the vehicle body or a predetermined acceleration (deceleration acceleration) acts on the vehicle body due to a collision or sudden braking. . The locking mechanism 100 is a well-known device.

  In the power transmission mechanism 24, for example, as shown in FIG. 3, the sun gear 114 is integrally coupled to the drive input external teeth 115, and the carrier 117 supporting the plurality of planetary gears 116 is coupled to the webbing reel 22. ing. A plurality of ratchet teeth 119 are formed on the outer peripheral side of the ring gear 118 meshed with the planetary gear 116, and these ratchet teeth 119 constitute a part of a clutch 120 described later. The clutch 120 appropriately connects and disconnects the power transmission system between the electric motor 23 and the webbing reel 22 under the control of the control device 30.

  The power transmission system on the electric motor side is provided with a small-diameter first connect gear 123 that is always meshed with the external gear 115 integral with the sun gear 114, and a large coaxial gear that is provided so as to rotate integrally with the first connect gear 123. A second connect gear 124 having a diameter, and first and second idler gears 126 and 127 which are between the second connect gear 124 and the electric motor gear 125 (integrated with the rotating shaft 23a of the electric motor 23) and are always meshed so as to be able to transmit power, It has.

The driving force in the forward rotation direction of the electric motor 23 is transmitted to the second and first connection gears 124 and 123 through the gears 125, 127, and 126 as indicated by solid arrows in FIG. After being transmitted to the sun gear 114, the planetary gear 116 and the carrier 117
Is transmitted to the webbing reel 22. The driving force in the forward direction of the electric motor 23 rotates the webbing reel 22 in a direction in which the webbing 13 is drawn (wound up). However, the driving force transmitted from the sun gear 114 to the planetary gear 116 is all transmitted as described above when the ring gear 118 is fixed. However, when the ring gear 118 is free to rotate, the planetary gear 116 rotates. The ring gear 118 is idled.

  The clutch 120 controls the locking and unlocking of the rotation of the ring gear 118 to turn on / off the transmission of the driving force of the electric motor 23 to the webbing reel 22.

  Here, the clutch 120 will be described with reference to FIG. The clutch 120 is rotatably supported by a casing (not shown), and can be engaged with a pawl 129 having a locking claw 128 at the tip, a clutch spring 130 for operating the pawl 129, and a locking claw 128 of the pawl 129. The locking claw 128 abuts against a surface substantially perpendicular to the inclined surface of the ratchet teeth 119 when the pawl 129 is operated in the direction of the ratchet teeth 119, and the ring gear 118 has one ratchet tooth 119. The rotation of the direction is locked.

  Further, the clutch spring 130 is bent in a circular arc shape at the base portion side, and the bent portion 131 is locked in a state of being wound around the outer periphery of the shaft portion of the first connect gear 123. The tip of the clutch spring 130 extends in the direction of the pawl 129 and engages with the operation window 132 of the pawl 129. The curved portion 131 of the clutch spring 130 is engaged with the shaft portion of the first connect gear 123 by friction, and when a torque greater than a set value acts between the first connect gear 123 and the first connect gear 123, Slips between the two.

  Therefore, in the clutch 120, when the electric motor 23 rotates in the forward rotation direction (see the solid line arrow in FIG. 3), the clutch spring 130 changes from the position shown by the solid line in FIG. As a result, the pawl 128 of the pawl 129 meshes with the ratchet teeth 119 as shown in FIG. 3 to lock the rotation of the ring gear 118. When the rotation of the ring gear 118 is thus locked, all the rotational force transmitted to the sun gear 114 as described above is transmitted to the webbing reel 22 as the rotation of the carrier 117 (clutch-on state).

  Note that the rotation of the ring gear 118 is locked only by the ratchet teeth 119 in the reverse direction of the ring gear 118 (counterclockwise in FIG. 3), and the rotation of the ring gear 118 in the forward direction is the locking of the pawl 129. The pawl 128 is allowed (not locked) by sliding on the ratchet teeth 119 of the ring gear 118. That is, when the electric motor 23 is driven in the forward rotation direction and the pawl 129 of the clutch 120 is operated in the direction of the ratchet teeth 119 as shown in FIG. 3, the carrier 117 on the webbing reel 22 side from the sun gear 114 on the electric motor 23 side. However, power transmission from the carrier 117 to the sun gear 114 is not possible because the ring gear 118 is not locked.

  On the other hand, when the electric motor 23 rotates in the reverse direction from the clutch-on state, the first connect gear 123 rotates as indicated by the dotted arrow in FIG. 3 and rotates the clutch spring 130 as indicated by the solid line in FIG. As a result, the pawl 128 of the pawl 129 is pulled away from the ratchet teeth 119, and the lock of the ring gear 118 is released. When the lock of the ring gear 118 is released in this way, the rotational force transmitted to the sun gear 114 rotates the planetary gear 116 as described above, and at this time the ring gear 118 is idled to drive the power toward the carrier 117 (webbing reel 22). Is not transmitted (clutch off state).

  FIG. 5 shows the internal configuration of the control device 30. The control device 30 controls the rotation or stop of the electric motor 23 according to the state of the vehicle. The control device 30 supplies the first current to the electric motor 23 in the first section (A in FIG. 6: inrush current section) for driving the stopped electric motor 23, and continues to the first section. In the second section (B in FIG. 6: initial drive current section), the electric motor 23 is supplied with a second current (for example, 1 A) smaller than the first current, and the electric motor 23 continues to rotate. For this reason, the control device 30 includes a control unit 31 and a motor drive control unit 32.

  A vehicle state detection unit 40 is connected to the control device 30 via a CAN (Controller Area Network) bus 50. The vehicle state detection unit 40 detects a collision precursor such as a buckle switch 19 that detects the connection state of the buckle 18 shown in FIG. 1, a radar that detects an object in front of the vehicle, an acceleration sensor that detects deceleration (acceleration) of the vehicle, and the like. It refers to a device (not shown). The control device 30 receives the on signal of the buckle switch 19 to detect the wearing of the webbing 13, and receives the collision sign signal from the collision sign detection device and drives the electric motor 23 to remove the slack of the webbing 13. Control is made as appropriate.

  The control unit 31 is realized by, for example, a microprocessor including a memory, and sequentially reads and executes a program recorded in the memory, whereby the control device 30 is electrically operated in an inrush current section in which the stopped electric motor 23 is driven. A function of supplying the first current to the motor 23 and supplying the second current (for example, 1A) smaller than the first current to the electric motor 23 in the initial drive current section to continue the rotation of the electric motor 23 is realized. Therefore, the retractor 16 (electric motor 23) is controlled via the motor drive control unit 32.

  When the motor drive control unit 32 receives a motor drive request, a motor reverse rotation request, or a motor stop request issued from the control unit 31, the motor drive control unit 32 drives the electric motor 23 of the retractor 16 to perform reverse control or stop control. Do. The motor drive control unit 32 is configured by, for example, a three-phase bridge circuit. Under the control of the control unit 31, the motor drive control unit 32 changes the duty ratio of the pulse width according to the magnitude of the input signal at a constant period (changes the ON pulse energization width) and drives the electric motor 23. The control and the current feedback control for increasing / decreasing the voltage between the terminals of the electric motor 23 with the target current value as the energization current value of the electric motor 23 are switched under the instruction of the control unit 31.

  In the inrush current section (A in FIG. 6), the control unit 31 supplies a voltage signal with a first duty (for example, 10% duty) to the electric motor 23, and the initial drive current section (B in FIG. 6). , Current feedback control is performed to control the electric motor 23 so that the second current becomes the command current value. In the rotation current section (the third section and C in FIG. 6) following the initial drive current section, the controller 31 sets the electric motor 23 to a second duty (for example, 15% duty) higher than the first duty. The third current supplied to the electric motor 23 is gradually increased by supplying the voltage signal of.

  When the vehicle state detection unit 40 detects the attachment of the buckle 18, the control unit 31 is more than the second current supplied in the initial drive current section in the fourth section (D in FIG. 6) following the rotation current section. The webbing 13 is loosened with a large fourth current (for example, 3 A). When the vehicle state detection unit 40 detects an acceleration equal to or greater than a predetermined value, the control unit 31 detects a fourth current (for example, a current larger than the current supplied in the initial drive current interval in the fourth interval following the rotation current interval). The webbing 13 is held and controlled in 3A).

  The inrush current section (first section) is shorter than the initial drive current section (second section), and the initial drive current section (second section) is equal to or greater than the rotational current section (third section). .

  When the vehicle state detection unit 40 detects the emergency state of the vehicle, the control unit 31 detects an emergency maximum state of the electric motor 23 with an allowable maximum current (for example, 20 A) larger than the first current instead of the first current in at least the inrush current section. ).

(Operation of the embodiment)
Hereinafter, the operation of the seat belt device 10 according to the present embodiment will be described in detail with reference to the timing chart of FIG. 6 and the flowchart of FIG.

  First, the control device 30 (the control unit 31), based on the output of the vehicle state detection unit 40, operates when the webbing 13 is mounted or the slack eliminating operation is performed in a state where the vehicle is not accelerated by a predetermined value or more. At this time, it is determined whether the operation is a comfort operation that gives priority to passenger comfort or a pre-crash operation in which acceleration of a predetermined value or more is detected in the vehicle to avoid collision or reduce collision at the time of collision (step S101).

  During the comfort operation (step S101 “comfort”), the control unit 31 determines whether or not the control timing is within an inrush current section for driving the electric motor 23 that is currently stopped (step S102). If it is an inrush current section (step S102 “YES”), the control unit 31 controls the motor drive control unit 32 to perform, for example, PWM (Pulse Width Modulation) drive with a duty of 10% (step 10). S103). This drive control is repeated for 5 [ms]. In addition, 5 [ms] is a time set for suppressing the inrush current of the electric motor 23 which normally reaches 20 [A].

  By performing duty control without using current feedback control in this inrush current section, it becomes possible to control such that the inrush current does not increase even if an inexpensive microprocessor using an operation clock with a relatively low frequency is used. . The duty 10% is a limit area where the electric motor 23 does not rotate, and is a number derived by experiments together with 5 [ms].

  If the above-described duty drive is continued for 5 [ms], that is, if it is not an inrush current section (step S102 "NO"), in the initial drive current section following the inrush current section (step S104 "YES"), the control unit 31 By controlling the drive control unit 32, current feedback control is performed with 1 [A] at which the electric motor 23 starts rotating as a target current (step S105). This drive control is repeatedly executed for 20 [ms]. In the seat belt device 10 according to the present embodiment, the power transmission mechanism 24 of the retractor 16 locks the rotation of the ring gear 118 at a timing after the current feedback control over 20 [ms] (symbol x in FIG. 6). All of the rotational force transmitted to the sun gear 114 becomes the rotation of the carrier 117 and enters the “clutch on” state transmitted to the webbing reel 22.

  Note that, by gradually increasing the current value in the initial drive current section by current feedback control, there is an advantage that individual differences of the electric motor 23 can be absorbed as compared with the case where duty control is performed.

  After the elapse of 20 [ms] by the current feedback control, that is, when it is not the initial current section (step S104 “NO”), in the rotation current section following the initial drive current section (step S106), the control unit 31 is a motor drive control section. 32 is controlled to perform PWM drive control for removing the slack of the webbing 13 by gradually increasing the rotational speed of the electric motor 23 from, for example, a duty of 10% to 15% (step S107). This drive control is repeated for 20 [ms]. This is a measure for eliminating a sense of incongruity due to a rapid speed increase of the electric motor 23.

  By continuing the above duty control for about 20 [ms] (step S106 “NO”), the webbing 13 is loosened (step S108), and if the tension applied to the webbing 13 reaches about 3 [A] ( In step S109 “YES”), the control unit 31 issues a reverse rotation command to the motor drive control unit 32 to drive the electric motor 23 in the reverse direction. Thus, the clutch 120 can be released and the electric motor can be stopped (step S110).

  When the vehicle state detection unit 40 detects an acceleration of a predetermined value or more that does not satisfy the pre-crash due to winding or the like, the control unit 31 removes slack in the motor rotation current section in the section D following the motor rotation current section. The occupant is held and controlled by applying tension to the webbing 13 that is higher than the current (3A) supplied when the operation is performed, for example, about 5 [A] (fourth current).

  Further, when the pre-crash operation is detected by the vehicle state detection unit 40 in step S101 (step S101 “pre-crash”), the control unit 31 controls the motor drive control unit 32 to perform an electric motor for emergency response. A current corresponding to an allowable maximum current of 20 [A] is supplied to 23 and the webbing 13 is wound up at once. If this is continued for 1 [s] (step S111 “YES”), the control unit 31 controls the motor drive control unit 32 to reversely drive the electric motor 23, thereby releasing the clutch 120 and switching the electric motor 23 over. Stop (step S110).

(Effect of embodiment)
According to the seatbelt device 10 according to the present embodiment, the first current is supplied to the electric motor 23 in the first section (rush current section) for driving the stopped electric motor 23, and the first section is supplied to the first section. In the subsequent second section (initial drive current section), the electric motor 23 is supplied with a second current (1A) smaller than the first current, and the electric motor 23 continues to rotate. Therefore, the rotation of the electric motor 23 at the time of starting can be suppressed, and the discomfort and discomfort given to the occupant can be reduced.

  In addition, in the first section, by supplying a voltage signal with a first duty to the electric motor 23, an inrush current is also generated by the control unit 31 incorporating an inexpensive microprocessor that operates with a clock having a relatively low frequency. Control that does not increase is possible. In addition, by controlling the electric motor 23 so that the second current becomes the command current value in the second section, an effect of absorbing individual differences of the electric motor 23 compared to when performing duty control is obtained. It is done.

  Further, in a third section (rotational current section) following the second section, a voltage signal with a second duty higher than the first duty is supplied to the electric motor 23 so that the third current of the electric motor 23 is gradually increased. By performing the control to be increased, the uncomfortable feeling due to the sudden speed increase of the electric motor 23 is eliminated, and the electric motor 23 is operated at a low speed and the clutch 120 is engaged slowly. , And the discomfort and discomfort given to the occupant can be reduced. In addition, the silencing effect is higher as the current value in the initial drive current section is smaller than, for example, the current value (3A) required for the slack removal of the webbing 13. Incidentally, the rotational speed of the clutch 120 having a silencing effect is approximately 30 deg / s.

  Moreover, according to the seatbelt apparatus 10 which concerns on this embodiment, if mounting | wearing of the buckle 18 is detected, in the 4th area (D of FIG. 6) following a 3rd area, it supplies in the 2nd area. The webbing is removed with a fourth current larger than the current of 2. Therefore, it is possible to control the electric motor 23 without monitoring the winding and drawing positions of the webbing 13 by the rotation angle sensor, and the webbing 13 can be reliably wound. In addition, when acceleration greater than a predetermined value is detected by winding or the like, webbing is held and controlled in a fourth section after the third section has elapsed with a fourth current larger than the current supplied in the second section. Thus, the occupant holding control can be reliably performed. Further, when an emergency state of the vehicle is detected, an unexpected situation occurs by supplying an allowable maximum current larger than the first current to the electric motor 23 at least in the first section instead of the first current. Even occupants can be reliably protected.

  As described above, according to the seat belt device 10 according to the present embodiment, it is possible to reliably drive the seat belt without giving a sense of discomfort to the occupant in both the comfort operation and the pre-crash operation.

  DESCRIPTION OF SYMBOLS 10 ... Seat belt apparatus, 13 ... Webbing, 16 ... Retractor, 22 ... Webbing reel, 23 ... Electric motor, 24 ... Power transmission mechanism, 30 ... Control apparatus, 31 ... Control part, 32 ... Motor drive control part, 40 ... Vehicle State detection unit, 50 ... CAN bus, 120 ... clutch

Claims (7)

A seat belt apparatus comprising: a webbing reel capable of winding webbing; an electric motor coupled to the webbing reel via a clutch; and a control unit configured to control rotation or stop of the electric motor according to a state of the vehicle. Because
The controller is
A first current is supplied to the electric motor in a first section for driving the stopped electric motor, and is smaller than the first current to the electric motor in a second section following the first section. Supplying a second current to continue the rotation of the electric motor;
Supplying a voltage signal with a first duty to the electric motor in the first section;
In the second section, the electric motor is controlled so that the second current becomes a command current value. The controller is
In a third section following the second section, a voltage signal with a second duty higher than the first duty is supplied to the electric motor to gradually increase the third current of the electric motor. 2. The seat belt device according to claim 1, wherein A vehicle state detection unit for detecting the state of the vehicle;
The controller is
When the vehicle state detection unit detects wearing of the buckle, in the fourth section following the third section, the webbing of the webbing is performed with a fourth current larger than the second current supplied in the second section. The seat belt device according to claim 2, wherein slack is removed. A vehicle state detection unit for detecting the state of the vehicle;
The controller is
When the vehicle state detection unit detects an acceleration equal to or greater than a predetermined value, the webbing is held at a fourth current that is larger than the current supplied in the second section in the fourth section following the third section. The seat belt device according to claim 2, wherein the seat belt device is controlled.   The seat belt device according to claim 1, wherein the first section is shorter than the second section.   The seat belt device according to any one of claims 2 to 5, wherein the second section is equal to or larger than the third section. A vehicle state detection unit for detecting the state of the vehicle;
The controller is
When the vehicle state detection unit detects an emergency state of the vehicle, an allowable maximum current larger than the first current is supplied to the electric motor instead of the first current at least in the first section. The seat belt device according to any one of claims 1 to 6.

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