JP2012228933A - Webbing take-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adequately and surely drive, by a simple structure, a motor that rotates a spool in a direction in which a webbing is taken up.SOLUTION: Electrodes 78A, 78B and electrodes 78B, 78C are provided on a rotating body 56 which is made rotatable integrally with a spool while having a fan-shaped pore 88 formed corresponding to the pressing part 90 of a torsion shaft 24. Upon the rotation of the torsion shaft together with the spool in the take-up direction by the biasing force of a convolution spring, the pressing part 90 presses an electrode shaft 100 by making an electrode 110 connect the electrodes 78B and 78C to drive the motor. Upon the spool coming to stop rotating owing to the webbing falling while being fully retracted and so forth, with a resulting increase in the output of the motor, an electrode shaft 102 in contact with the pressing part is pushed wile an electrode 112 releases a contacted state between the electrodes 78A and 78B, thereby stopping the drive of the motor.

Description

  The present invention relates to a webbing take-up device provided in a seat belt device of a vehicle, and more particularly to a webbing take-up device that winds webbing by a driving force of a motor.

  In some webbing take-up devices, a spool is rotated in the take-up direction by a driving force of a motor, and the webbing is wound in a layered manner around a take-up shaft and stored. For example, in Patent Document 1, when the webbing winding is started by driving the motor with a certain time delay after releasing the engagement between the tongue plate and the buckle, and when the webbing tension exceeds a predetermined value, and It has been proposed to stop driving the motor when the entire webbing winding is detected.

  Further, in Patent Document 2, when it is detected that the engagement between the tongue plate and the buckle is released, and in a state where the engagement between the tongue plate and the buckle is released, it is rotated in the winding direction by the return spring. When this is detected, the driving of the motor is started, and when the time measured by the timer reaches a predetermined time, the driving of the motor is stopped assuming that the entire winding of the webbing has been completed.

Japanese Utility Model Publication No. 02-071055 JP 2001-225720 A

  By the way, in order to drive / stop the winding motor by detecting the webbing tension, detecting the total amount of webbing, and determining the timing of the total amount of webbing, the motor is controlled using an expensive control device such as an ECU. In addition, a mechanism for detecting the tension of the webbing, detecting the rotation direction of the spool, winding the entire amount of the webbing, and the like is necessary. For this reason, the configuration of the motor control system is complicated and expensive.

  The present invention has been made in view of the above-described facts, and an object thereof is to provide a webbing take-up device that controls a motor with a simple and inexpensive configuration.

  The invention according to claim 1, which achieves the above object, includes a spool that winds the webbing when the longitudinal base end side of the long webbing is locked and rotated in the winding direction, and the spool is wound on the winding. Winding attachment urging means for urging in the direction; motor for rotating the spool in the winding direction when supplied with driving power; and driving force transmitting means for transmitting the driving force of the motor to the spool; Rotation of the spool in the winding direction provided in the driving force transmitting means, closed by rotating the spool in the winding direction by the winding attachment biasing means, and rotated by the driving force of the motor A rotation detection switch including a contact opened by the driving force of the motor increased by regulating the motor, and the contact of the rotation detection switch is closed to close the mode. Starts the supply of driving power to the motor, including a power supply means for stopping the supply of the driving power to the motor by the contact is opened.

  According to the first aspect of the present invention, the spool rotates in the pull-out direction by pulling out the webbing for the seat belt to be worn. When the seat belt is removed, the spool is biased in the winding direction by the winding attachment biasing means. As a result, when the spool rotates in the winding direction, the contact of the rotation detection switch is closed, the drive of the motor at the rated output is started, and the webbing is wound around the spool by the driving force of the motor and stored.

  Further, when the webbing is fully retracted, the rotation of the spool is stopped, and the output of the motor that rotates the spool is increased (the driving force is increased). Thereby, when the contact of the rotation detection switch is opened, the supply of driving power to the motor is stopped.

  According to a second aspect of the present invention, in the first aspect of the present invention, the power supply device further includes a mounting release detection switch including a mounting release contact that is closed when the webbing state of the occupant is released. And the driving power is supplied to the motor when the contact of the rotation detection switch is closed.

  According to the present invention, the mounting release detection switch uses the mounting release contact that is opened when the occupant wears the webbing and is closed when the webbing is released, and the mounting release contact is closed. The driving power is supplied to the motor by closing the contact.

  According to a third aspect of the present invention, in the second aspect of the present invention, the spool is wound around the spool by rotating the drive force transmitting means relative to the spool within a predetermined rotation angle range and transmitting the drive force of the motor. A rotating body that rotates in the take-up direction, wherein the rotation detection switch closes when the rotating body is rotated by rotation of the spool in the winding direction; and A second contact that is opened when the spool is rotated in the winding direction by a driving force of a motor, and the power supply means is configured to close the mounting release contact and the second contact, and Supply of the driving power to the motor is started when the first contact is closed, and the drive to the motor is started when at least one of the mounting release contact and the second contact is released. To stop the supply of electric power.

  According to the third aspect of the present invention, when the rotating body rotates following the spool rotating in the winding direction by the urging force of the winding mounting urging means, the first contact is closed to drive the motor. Is started.

  Further, when the webbing is fully retracted and the force for the rotating body to rotate the spool increases, the second contact is released, the supply of power to the motor is stopped, and the motor is driven. Is stopped.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the driving force transmitting means is provided so as to be rotatable relative to the spool within a predetermined rotation angle range, and the driving force of the motor is transmitted. And a rotating body that rotates the spool in the winding direction, and swings to a position where the spool and the rotating body rotate together by relative rotation of the spool in the winding direction and the drawing direction with respect to the rotating body. And an operation member provided on the rotation detection switch and moved to follow the swing of the operation member to open and close the contact.

  According to the fourth aspect of the present invention, after the spool rotates relative to the rotating body in the winding direction, the spool and the rotating body can integrally rotate in the winding direction. At this time, the operating member is swung, and the moving member moves following the swinging of the operating member, whereby the contact is closed and the motor is driven.

  Further, when the webbing is wound up to the fully retracted state by driving the motor, the rotation of the spool is stopped, the output of the motor rotating the spool is increased and the driving force is increased, so that the contact is opened and the motor is rotated. The drive power supply stops.

  As described above, according to the first aspect of the present invention, when the spool is started to rotate in the winding direction by the winding attachment biasing means, the contact is closed and the webbing is fully retracted. Since the rotation detection switch that opens the contact point by the driving force that increases when the motor stops is used, the motor can be driven at a precise timing with a simple configuration.

  According to the second aspect of the present invention, since the mounting detection switch that enables the motor to be driven by releasing the mounting of the webbing by the occupant is provided, the occupant can accurately operate the motor only when the webbing is not mounted. It can be driven.

  According to the third aspect of the present invention, it is possible to accurately detect the rotation start of the spool in the winding direction of the spool by the winding attachment biasing means and the rotation stop of the spool driven by the driving force of the motor.

  According to the fourth aspect of the present invention, the opening and closing of the contact point is delayed by using the moving member that moves following the relative rotation of the spool and the rotating body and the swinging of the operating member. The motor can be driven and stopped at an appropriate timing.

It is a perspective view which shows schematic structure of the webbing winding device applied to 1st Embodiment. It is a perspective view which shows schematic structure of the switchgear which concerns on 1st Embodiment. It is a schematic block diagram of the principal part of a switchgear. It is a schematic block diagram of the principal part of a switchgear, and has shown the state which the spool rotated relatively to the extraction | drawer direction. It is a schematic block diagram of the principal part of a switchgear, and has shown the state which the spool rotated relatively to the winding direction. It is the schematic which shows the electric power feeding circuit which concerns on 1st Embodiment. (A) is a flowchart which shows drawing | extracting of the webbing in a webbing winding device, (B) is a flowchart which shows winding of a webbing in a webbing winding device. It is a perspective view which shows schematic structure of the webbing winding device which concerns on 2nd Embodiment. (A) is a schematic block diagram of the principal part of a switchgear, (B) is a schematic block diagram of the principal part of the switchgear seen from the direction different from (A). It is the schematic which shows the electric power supply to the motor which concerns on 2nd Embodiment. It is a diagram which shows the outline of a movement of the slide member with respect to rotation of the operation member in a switch unit.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 shows a webbing take-up device 10 applied to the first embodiment. The webbing take-up device 10 includes a frame 12. The frame 12 is formed by a back plate 14 fixed to a frame (not shown) of the vehicle, and leg plates 16 and 18 extending in pairs from both ends in the width direction of the back plate 14.

  In the webbing take-up device 10, a spool 20 serving as a take-up shaft is rotatably supported between a pair of leg plates 16 and 18 of the frame 12. The spool 20 has a substantially cylindrical shape, and one end side (base end side) in the longitudinal direction of the webbing 22 formed in a long band shape is locked. The webbing 22 is wound up in layers on the outer periphery of the spool 20 from the base end side in the longitudinal direction, and the tip end side is pulled out upward of the vehicle.

  The spool 20 is provided with a torsion shaft 24 at its axial center, and is rotated integrally with the torsion shaft 24 by, for example, one end side in the axial direction being connected to the torsion shaft 24. In FIG. 1, a part of the torsion shaft 24 is shown.

  The webbing take-up device 10 is provided with a lock mechanism and a pretensioner mechanism on the outside of one leg plate 16 of the frame 12 (on the side opposite to the other leg plate 18). The shaft end portion of the torsion shaft 24 protruding from the spool 20 is connected to the lock mechanism and the pretensioner mechanism.

  The lock mechanism is activated when the vehicle suddenly decelerates or when the spool 20 suddenly rotates in the direction in which the webbing 22 is pulled out, and the pulling direction in which the webbing 22 of the spool 20 is pulled out (hereinafter simply referred to as the pulling direction). ) Is restricted. Further, the pretensioner mechanism forcibly rotates the spool 20 in the winding direction (hereinafter simply referred to as the winding direction) for winding the webbing 22 when the vehicle decelerates rapidly. A known configuration can be applied to such a lock mechanism and pretensioner mechanism, and illustration and detailed description thereof are omitted in the present embodiment.

  On the other hand, the webbing take-up device 10 is provided with a take-up unit 26 on the outer side of the other leg plate 18 of the frame 12 (on the side opposite to the one leg plate 16). The winding unit 26 includes a motor 28 serving as a driving unit when winding the webbing 22 around the spool 20, a driving force transmission mechanism 30 that transmits the driving force of the motor 28 to the spool 20, a unit case 32, and a spring unit 34. It is formed including.

  The unit case 32 includes a case main body 36 formed in a shallow box shape with one surface opened, and the case main body 36 is attached to the leg plate 18 with the opening side facing away from the leg plate 18. ing. The case main body 36 accommodates a motor 28 and a driving force transmission mechanism 30. Further, a cover 38 is provided on the opening side of the case body 36, and the case body 36 is closed by the cover 38.

  A motor housing portion 40 is provided in the case main body 36, and the motor 28 is housed in the motor housing portion 40. When the motor 28 is housed in the motor housing portion 40, the axial direction of the output shaft 42 is along the axial direction of the spool 20, and the output shaft 42 is directed to the side opposite to the leg plate 18.

  The driving force transmission mechanism 30 includes a spur gear 44, which is attached to the output shaft 42 of the motor 28 and is rotated integrally with the output shaft 42 of the motor 28. The driving force transmission mechanism 30 includes two-stage gears 46 and 48 and a switch gear 50. In the two-stage gear 46, a large-diameter gear portion having more teeth than the gear 44 and a small-diameter gear portion having fewer teeth than the large-diameter gear portion are coaxially formed integrally, and the small-diameter gear portion is a leg plate. It arrange | positions so that it may become 18 side. In the two-stage gear 48, a large-diameter gear part having more teeth than the small-diameter gear part of the two-stage gear 46 and a small-diameter gear part having fewer teeth than the large-diameter gear part are coaxially integrated. The small-diameter gear portion is formed and arranged on the leg plate 18 side.

  The two-stage gear 46 has a support shaft 52 inserted through an axial center thereof and is rotatable with respect to the support shaft 52. Further, the two-stage gear 48 is rotatable with respect to the support shaft 54 by inserting a support shaft 54 through the shaft center portion. The support shafts 52 and 54 are disposed so that the axial direction thereof is along the axial direction of the spool 20, one end side in the axial direction is supported by the bottom portion of the case body 36, and the other end side in the axial direction is supported by the cover 38. Thereby, the two-stage gears 46 and 48 are rotatably supported by the case main body 36 and the cover 38.

  The other end side in the axial direction of the torsion shaft 24 protrudes from the leg plate 18, and a switch gear 50 is connected to the torsion bar 24 protruding from the leg plate 18. The switch gear 50 includes a rotating body 56. The rotating body 56 is disposed so as to be coaxial with the spool 20, that is, the torsion shaft 24, and is rotatable integrally with the torsion shaft 24. A spur gear portion 60 is formed on the outer periphery of the rotating body 56.

  In the driving force transmission mechanism 30, the large-diameter gear portion of the two-stage gear 46 is engaged with the gear 44 of the output shaft 42 of the motor 28, and the small-diameter gear portion of the two-stage gear 46 and the large-diameter gear portion of the two-stage gear 48. Is in mesh. In the driving force transmission mechanism 30, the small-diameter gear portion of the two-stage gear 48 is engaged with a gear portion 60 formed on the rotating body 56 of the switch gear 50.

  Thereby, in the webbing take-up device 10, when the output shaft 42 of the motor 28 is rotationally driven, this rotational driving force is transmitted from the gear 44 to the rotating body 56 of the switch gear 50 through the two-stage gears 46 and 48. Is done. Thereby, when the rotating body 56 of the switch gear 50 and the torsion shaft 24 rotate together, the spool 24 is rotated by the rotation of the motor 28.

  In the webbing take-up device 10, the motor 28 rotates the spool 20 in the take-up direction of the webbing 22 (arrow A direction). Therefore, in the webbing take-up device 10, the webbing 22 is taken up on the spool 20 by rotating the spool 20 by the driving force of the motor 28.

  On the other hand, the winding unit 26 is provided with a spring case 62 of the spring unit 34. The spring case 62 has a substantially cylindrical shape with a shallow bottom, and is disposed on the side of the cover 38 opposite to the leg plate 18, with the opening side facing the cover 38. The spring case 62 is attached to at least one of the leg plate 18 or the cover 38 of the frame 12.

  A through hole 64 that is coaxial with the spool 20 is formed in the cover 38, and the through hole 64 is covered with the spring case 62. One end 66 of the torsion shaft 24 is inserted into the through hole 64 of the cover 38, and the protruding tip is rotatably supported by the spring case 62.

  A spiral spring 68 serving as an urging means is accommodated in the spring case 62. The spiral spring 68 has an outer peripheral end locked to the inner peripheral surface of the spring cover 62, and an inner peripheral end locked to the shaft end portion 66 of the torsion shaft 24. The spiral spring 68 is wound by the torsion shaft 24 being rotated in the pull-out direction (arrow B direction) and accumulates an urging force, and urged to rotate the torsion shaft 24 in the winding direction by the urging force. To do.

  Here, some webbing take-up devices have a configuration in which the webbing is taken up on the spool only by the urging force of the spiral spring. The spiral spring 68 used in the webbing take-up device 10 according to the present embodiment is as described above. The biasing force is weaker than the biasing force of a biasing means such as a spiral spring used in a simple webbing winding device.

  In the webbing take-up device 10, when an occupant pulls out the webbing 22 and engages a tongue plate (not shown) with a buckle (buckle device) and attaches a seat belt, the webbing 22 is applied by the urging force accumulated in the spiral spring 68. The webbing 22 is in close contact with the occupant's body. Further, in the webbing take-up device 10, when the occupant releases the engagement between the tongue plate and the buckle in order to remove the seat belt, the spool 20 is rotated in the take-up direction by the weak biasing force of the spiral spring 68. In the webbing winding device 10, the motor 28 is driven by the rotation in the winding direction, and the spool 20 rotates in the winding direction to wind the webbing 22.

  Incidentally, in the webbing take-up device 10, driving and stopping of the motor 28 are switched according to the rotation of the switch gear 50. FIG. 2 shows a schematic configuration of the switch gear 50. FIG. 2 shows a schematic configuration of the switch gear 50 as viewed from the spool 20 side.

  The rotating body 56 of the switch gear 50 is formed in a shallow bottomed cylinder shape, and the opening side is directed to the leg plate 18 side of the frame 12 (see FIG. 1). The switch gear 50 is provided with a cover 58 so as to face the opening (the leg plate 18 side) of the rotating body 56. The cover 58 is formed in a substantially disc shape, and is disposed on the leg plate 18 side of the rotating body 56 so as to be coaxial with the rotating body 56.

  The cover 58 is formed with a boss portion 72 at the axial center portion of the bottom portion 70. The boss portion 72 is formed with a through hole 74 penetrating along the axial direction of the spool 20. The through hole 74 has a non-circular shape such as a polygonal shape, a star shape, or an elliptical shape. The torsion shaft 24 is inserted into the insertion hole 74. The torsion shaft 24 is formed with an insertion portion (not shown) having an outer shape corresponding to the inner peripheral shape of the insertion hole 74, and the insertion portion is fitted into the insertion hole 74.

  As a result, the cover 58 is rotated integrally with the torsion shaft 24. In the present embodiment, the cover 58 rotates integrally with the torsion shaft 24. However, the present invention is not limited to this, and the cover 58 may rotate integrally with the rotating body 56. Further, the cover 58 can be omitted.

  In the rotating body 56, a plurality of electrodes are arranged on the surface of the bottom portion 76 on the cover 58 side (the surface on the side covered with the cover 58). In this embodiment, as an example, three types of electrodes 78A, 78B, and 78C are used, one electrode 78A and 78C are provided, and two electrodes 78B are provided.

  As shown in FIGS. 2 to 5, the electrodes 78 </ b> A to 78 </ b> C are formed in an arc shape having a predetermined width and different inner diameters. The inner diameters of the electrodes 78A to 78C are the smallest for the electrode 78A and the largest for the electrode 78C. The rotating body 56 has an electrode 78A on the radially inner side, an electrode 78C on the radially outer side, and an electrode 78B facing the electrodes 78A and 78C, respectively, It is attached so that it may become coaxial with the rotary body 56 so that between may become a predetermined space | interval. 3 to 5 show a schematic configuration of a main part when the rotary body 56 of the switch gear 50 is viewed from the spool 20 side.

  A boss 82 is formed at the axial center of the bottom 76 of the rotating body 56. A through hole 84 is formed in the axial center portion of the boss portion 82. The through hole 84 is coaxial with the spool 20, has a substantially same diameter as the outer diameter of the torsion shaft 24, and a circular hole portion 86 into which the torsion shaft 24 is rotatably inserted. The fan-shaped hole 88 is connected.

  The torsion shaft 24 is formed with a pressing portion 90 corresponding to the fan-shaped hole 88 of the rotating body 56. The pressing portion 90 has a substantially rectangular shape, and protrudes outward in the radial direction from the outer peripheral surface of the torsion shaft 24. As shown in FIGS. 3 to 5, the torsion shaft 24 is inserted into the circular hole portion 86 of the insertion hole 84, and the pressing portion 90 is fitted into the fan-shaped hole portion 88.

  Here, the fan-shaped hole 88 of the rotating body 56 has a substantially fan shape with the circular hole 86 side as an axis, so that the torsion shaft 24 has a predetermined angular range (for example, the pressing portion 90 has a fan-shaped hole). 3 is within the range of contact with the inner wall surface 92A and the inner wall surface 92B of the portion 88 (the range of the approximate angle θ shown in FIG. 3), and can be rotated relative to the rotating body 56, and exceeds the range where relative rotation is possible. Thus, the rotating body 56 is rotated integrally.

  Thereby, when the torsion shaft 24 is rotated in the winding direction (arrow A direction) by the biasing force of the spiral spring 68, or when the rotating body 56 is rotated in the winding direction by the driving force of the motor 28, The shaft 24 and the rotating body 56 temporarily rotate relative to each other, but thereafter rotate integrally in the winding direction. That is, in the switch gear 50, the rotating body 56 and the torsion shaft 24 can follow and rotate with a predetermined phase difference.

  As shown in FIGS. 2 and 3 to 5, the switch gear 50 is provided with electrode shafts 100 and 102. As shown in FIGS. 3 to 5, the electrode shafts 100 and 102 are arranged such that the tip ends are sandwiched by the fan-shaped hole 88, and the longitudinal direction is the surface of the pressing portion 90 that is in contact with the inner peripheral surfaces 92 </ b> A and 92 </ b> B. It is arranged along the direction that intersects (substantially orthogonal). The electrode shafts 100 and 102 are supported by a plurality of receiving portions 80 provided on the surface of the bottom portion 76 of the rotating body 56 on the cover 58 side so as to be movable along the longitudinal direction.

  A stopper 104 is formed on the electrode shafts 100 and 102 at a predetermined position near the tip on the fan-shaped hole 88 side. The electrode shafts 100 and 102 are provided with coil springs 106 </ b> A and 106 </ b> B between the end opposite to the fan-shaped hole 88 and the inner peripheral surface of the rotating body 56. The coil spring 106A biases the distal end side of the electrode shaft 100 toward the fan-shaped hole 88, and the coil spring 106B biases the distal end side of the electrode shaft 102 toward the fan-shaped hole 88.

  On the bottom 76 of the rotator 56, a frame 108 that surrounds the fan-shaped hole 88 protrudes from the surface on the cover 58 side toward the cover 58. The electrode shafts 100 and 102 are inserted into an insertion hole (not shown) formed in the frame portion 108 around the fan-shaped hole portion 88, and the tip portion protrudes into the fan-shaped hole portion 88. At this time, the electrode shafts 100 and 102 are urged by the coil springs 106 </ b> A and 106 </ b> B so that the stopper 104 comes into contact with the frame portion 108, whereby the tip ends are projected into the fan-shaped hole 88 by a predetermined length.

  The electrode shafts 100 and 102 are pushed out of the fan-shaped hole 88 against the biasing force of the coil spring 106A or the coil spring 106B when the torsion shaft 24 rotates and the pressing portion 90 presses the tip portion. So that it is moved along the longitudinal direction (see FIGS. 4 and 5).

  The electrode shaft 100 is provided with an electrode 110 serving as a first contact at an outer peripheral portion at a predetermined position along the longitudinal direction, and the electrode shaft 102 has a second outer peripheral portion at a predetermined position along the longitudinal direction. An electrode 112 is provided as a contact.

  As shown in FIGS. 2 to 5, in the switch gear 50, the set of the electrode 78A and the electrode 78B is provided at a position corresponding to the electrode 112 of the electrode shaft 102, and the set of the electrode 78B and the electrode 78C. Is provided at a position corresponding to the electrode 110 of the electrode shaft 100. As shown in FIG. 5, the electrode 110 provided on the electrode shaft 100 has a predetermined width in the longitudinal direction of the electrode shaft 100, and the tip of the electrode shaft 100 resists the biasing force of the coil spring 106 </ b> A by the pressing portion 90. Then, when pushed into the frame portion 108, the electrodes 78B and 78C are brought into contact, and the electrodes 78B and 78C are electrically connected (contacts are closed). As shown in FIGS. 3 and 4, the electrode 110 is released from being pressed by the pressing portion 90, and the tip of the electrode shaft 100 is protruded into the fan-shaped hole 88 by the biasing force of the coil spring 106 </ b> A. Accordingly, the electrode 78C is separated from the electrode 78C and the electrode 78B and the electrode 78C are opened (contacts are opened).

  As shown in FIGS. 3 and 5, the electrode 112 provided on the electrode shaft 102 has a predetermined width in the longitudinal direction of the electrode shaft 102, the pressure by the pressing portion 90 is released, and the urging force of the coil spring 106 </ b> B. Thus, when the tip of the electrode shaft 102 protrudes into the fan-shaped hole 88, the electrode 78A comes into contact with the electrode 78B, and the electrode 78A and the electrode 78B are electrically connected (contacts are closed). As shown in FIG. 4, when the tip of the electrode shaft 102 is pushed into the frame portion 108 against the urging force of the coil spring 106B by the pressing portion 90, the electrode 112 is separated from the electrode 78A, The space between 78A and electrode 78B is opened (contacts are opened).

  As a result, the electrode shaft 100 provided with the electrode 110 opens and turns off the contact in a normal state where the electrode 110 is turned off, and closes the contact and turns on when the spool 20 rotates in the winding direction. The electrode shaft 102 provided with the electrode 112 constitutes a winding stop switch 116 that closes and turns on the contact in the normal state, and opens and turns off the contact by rotation of the spool 20 in the drawing direction. Yes.

  As described above, the spiral spring 68 has the weakest urging force in the fully retracted state where the webbing 22 is wound around the spool 20, and the urging force is gradually increased by rotating the spool 20 in the pulling-out direction from the withdrawal of the webbing 22. To increase.

  Here, the urging force of the coil spring 106A forming the winding start switch 114 resists the contact resistance (friction resistance) between the electrode 110 and the electrodes 78B and 78C, and the tip of the electrode shaft 100 is placed in the fan-shaped hole 88. The urging force can be projected. Further, the biasing force of the coil spring 106B forming the winding stop switch 116 is such that the tip of the electrode shaft 102 can protrude into the fan-shaped hole 88 against the contact resistance between the electrode 112 and the electrodes 78A and 78B. It is considered a power.

  Here, the urging force of the coil spring 106 </ b> A is weaker than the urging force of the spiral spring 68 that the pressing portion 90 presses the electrode shaft 100 when the webbing 22 is pulled out by a predetermined amount or more. That is, when the spiral spring 68 urges the torsion shaft 24 in the winding direction, the force by which the pressing portion 90 presses the electrode shaft 100, and the urging force by which the coil spring 106A presses the pressing portion 90 at the tip of the electrode shaft 100. It is getting bigger.

  As a result, in the webbing take-up device 10, the torsion shaft 24 is rotated in the take-up direction by the urging force of the spiral spring 68 in a state where the webbing 22 is pulled out by a predetermined amount or more, and the pressing part 90 is the tip part of the electrode shaft 100. Is pressed, the electrode shaft 100 is moved along the longitudinal direction against the biasing force of the coil spring 106A, and the winding start switch 114 is turned on.

  On the other hand, in the webbing take-up device 10, a DC motor is used as the motor 28. When the spool 20 is rotated by the driving force of the motor 28 and the webbing 22 is wound around the spool 20, friction generated when the spool 20 rotates. The force that the spool 20 pulls the webbing 22 (the weight of the webbing 22, the tension of the webbing 22, etc.) becomes a load on the motor 28. In a state where the spool 20 is rotated in the winding direction by the driving force of the motor 28, the output (driving force) of the motor 28 is set to a substantially rated output. Further, in the webbing take-up device 10, when the rotation of the spool 20 is stopped because the webbing 22 is in a fully retracted state in which substantially the entire amount of the webbing 22 is taken up by the spool 20 rotated by the driving force of the motor 28, When the spool 20 is rotated in the pulling direction against the driving force of the motor 28 by pulling out the webbing 22 in the middle of taking, the load on the motor 28 increases so that the output of the motor 28 is higher than the rated output. Become. In the webbing take-up device 10, when the output of the motor 28 increases, the pressing force when the rotating body 56 presses the pressing portion 90 of the torsion shaft 24 increases.

  In the winding stop switch 116, when the spool 20 is rotated by the driving force of the motor 28 and the webbing 22 is being wound, the tip of the electrode shaft 102 projects into the fan-shaped hole 88 by the biasing force of the coil spring 106B. Has been.

  However, when the output of the motor 28 increases due to the spool 20 being in a rotation stop state despite the motor 28 being driven, the winding stop switch 116 causes the electrode shaft to be urged by the biasing force of the coil spring 106B. The pressing force that the tip of the electrode shaft 102 receives from the pressing portion 90 is greater than the force with which the tip of the 102 presses the pressing portion 90. That is, the biasing force of the coil spring 106B is applied to the electrode shaft by the pressing portion 90 of the torsion shaft 24 when the output of the motor 28 becomes higher than the rated output due to the rotation stop of the spool 20 or the rotation of the spool 20 in the pulling direction. An urging force 102 is pushed from the fan-shaped hole 88. Note that such a coil spring 106B has a biasing force (spring strength) in consideration of friction generated by rotation of the spool 20, friction generated when the electrodes 110 and 112 move while in contact with the electrodes 78A to 78C, and the like. As long as is set.

  In the webbing take-up device 10, when the spool 20 is rotated in the take-up direction by the driving force of the motor 28 (the rated output state of the motor 28), the pressing portion 90 of the torsion shaft 24 pushes the tip of the electrode shaft 102. The force with which the biasing force of the coil spring 106B presses the pressing portion 90 with the electrode shaft 102 is greater than the pressing force.

  In the webbing take-up device 10, when the spool 20 and the torsion shaft 24 are rotated in the take-up direction by the urging force of the spiral spring 68 by releasing the engagement between the tongue plate and the buckle, the take-up start switch 114 turns on. In the webbing take-up device 10, when the take-up start switch 114 is turned on, the motor 28 is driven. In the webbing take-up device 10, when the spool 20 is rotated in the take-up direction by driving the motor 28, the webbing 22 is fully retracted, and the rotation of the spool 20 stops, so that the output of the motor 28 is increased. To rise. In the webbing take-up device 10, the drive of the motor 28 is stopped when the take-up stop switch 116 is turned on.

  As shown in FIG. 1, the rotating body 56 of the switch gear 50 is provided with ring-shaped electrodes 118 </ b> A, 118 </ b> B, 118 </ b> C on the surface of the bottom 76 opposite to the leg plate 18. The electrodes 118A to 118C have a predetermined width and different diameters, the electrode 118A is the radially inner side, the electrode 118C is the radially outer side, and the electrode 118B is the electrode 118A and the electrode 118C. Are attached so as to be coaxial with each other at a predetermined interval.

  As shown in FIGS. 3 to 5, in the switchgear 50 provided in the webbing take-up device 10, the electrode 78A and the electrode 118A, the electrode 78B and the electrode 118B, and the electrode 78C and the electrode 118C are paired, respectively. . That is, the electrodes 118A to 118C have the same width as the electrodes 78A to 78C, and the inner diameters are the same as the curved inner diameters of the electrodes 78A to 78C.

  In the switch gear 50, the electrode 78A is connected to the electrode 118A, the electrode 78B is connected to the electrode 118B, and the electrode 78C is connected to the electrode 118C. In such a form, for example, openings are formed at positions corresponding to the electrodes 78A to 78C of the bottom 76 of the rotating body 56, and members forming the electrodes 78A to 78C are projected from the electrodes 118A to 118C, respectively. Any configuration can be applied as long as the electrodes 78A to 78C and the electrodes 118A to 118C are electrically connected. In the present embodiment, the electrodes 78A to 78C are formed in an arc shape. However, the present invention is not limited to this. For example, an arbitrary shape such as a ring shape similar to the electrodes 118A to 118C may be applied. Can do.

  On the other hand, the winding unit 26 is provided with brush electrodes 120A, 120B, and 120C. The brush electrodes 120A to 120C are disposed on the opposite side of the leg plate 18 from the rotating body 56 of the switch gear 50 and face the electrodes 118A to 118C. Here, the brush electrode 120A is in contact with the electrode 118A, the brush electrode 120B is in contact with the electrode 118B, and the brush electrode 120C is in contact with the electrode 118C. Further, each of the brush electrodes 120A to 120C is in sliding contact with the electrodes 118A to 118C even when the rotating body 56 is in a rotating state, and the electrical connection state with the electrodes 118A to 118C is maintained.

  FIG. 6 shows a power feeding circuit 122 of the motor 28 in the webbing take-up device 10. The power supply circuit 122 is provided with a drive relay 124, and the motor 28 is connected to a battery (not shown) of the vehicle via a contact 126 of the drive relay 124. As a result, in the power feeding circuit 122, the driving relay 124 is turned on and the contact 126 is closed, whereby battery power is supplied to the motor 28 and the motor 28 is driven to rotate.

  In the seat belt device provided with the webbing take-up device 10, a buckle switch 128 is provided. The buckle switch 128 is turned on when a tongue plate (not shown) is engaged with the buckle to open the contact 130, and is turned off when the engagement between the buckle and the tongue plate is released to close the contact 130.

  In the power feeding circuit 122, a winding start switch 114, a winding stop switch 118, an exciting coil (not shown) of the drive relay 124, and a buckle switch 128 are connected in series. That is, the brush electrode 120C is connected to a battery (+ B) (not shown), the brush electrode 120B is between the winding start switch 114 and the winding stop switch 116, and the brush electrode 120A is connected to one of the excitation coils of the drive relay 124. The other excitation coil of the drive relay 124 is connected to the ground side (GND) via the buckle switch 128 (contact 130). In the power feeding circuit 122, the contact 132 of the drive relay 124 is connected in parallel with the winding start switch 114. The contact 132 is a normally open contact that is closed when the exciting coil of the drive relay 124 is energized and the drive relay 124 is turned on.

  As a result, when the winding start switch 114 is turned on while the buckle switch 128 is turned off (disengaged) and the winding stop switch 116 is turned off, the exciting coil of the driving relay 124 is energized, and the driving relay 124 is turned on. Turn on. Thereby, electric power of a constant voltage (+ B, for example, 12V) is supplied to the motor 28, and the motor 28 is driven. Further, in the power feeding circuit 122, when the contact 132 is closed by turning on the driving relay 124, the on state of the driving relay 124 is continued regardless of the on / off of the winding start switch 114 (self-holding). Therefore, in the power feeding circuit 122, when power feeding to the motor 28 is started, the winding stop switch 116 is turned off or the driving relay 124 is turned off by turning on the buckle switch 128 (self-holding release). Thereby, the power supply to the motor 28 is stopped, and the motor 28 is stopped.

  In the webbing retractor 10 configured as described above, when the occupant pulls the webbing 22 in order to wear the seat belt, the spool 20 is rotated in the pull-out direction, and the webbing 22 is pulled out. Thereafter, in the webbing take-up device 10, when the occupant wears the seat belt by pulling out the webbing 22 and engaging the tongue plate with the buckle, the webbing 22 is tensioned by the urging force of the spiral spring 68, The webbing 22 is brought into close contact with the occupant's body.

  In the webbing take-up device 10, when the occupant removes the seat belt by releasing the engagement between the tongue plate and the buckle, the spool 20 is rotated in the take-up direction by the urging force of the spiral spring 68, and the webbing 22 is spooled. Take up to 20. At this time, the webbing take-up device 10 drives the motor 28 to rotate the spool 20 in the take-up direction, thereby winding the webbing 22 onto the spool 20 until it is fully retracted.

  Incidentally, in the webbing take-up device 10, a switch gear 50 is provided between the torsion shaft 24 and the motor 28, and the motor 28 is driven / stopped according to the rotation of the switch gear 50.

  Here, with reference to FIG. 7A and FIG. 7B, the drawing and winding of the webbing 22 in the webbing winding device 10 will be described. FIG. 7A shows a flow when the webbing 22 is pulled out, and FIG. 7B shows a flow when the webbing 22 is taken up. In the following, the step numbers in FIGS. 7A and 7B are written in parentheses.

  When the occupant is not wearing the seat belt, such as when the webbing 22 is fully retracted, the buckle switch 128 is turned off and the contact 130 is closed (step 200). When the webbing 22 is pulled to attach the seat belt in this state (step 202), the spool 20 is rotated in the pull-out direction (step 204).

  When the spool 20 is rotated in the pull-out direction, the pressing portion 90 of the torsion shaft 24 comes into contact with the inner peripheral surface 92B of the fan-shaped hole 88 of the rotating body 56, thereby following the torsion shaft 24 and rotating the rotating body 56. Is rotated. That is, the rotating body 56 rotates integrally with the torsion shaft 24 with a delay until the pressing portion 90 of the torsion shaft 24 contacts the inner peripheral surface 92B of the fan-shaped hole 88.

  Here, as shown in FIG. 4, in the switch gear 50, when the torsion shaft 24 and the rotating body 56 rotate integrally in the pull-out direction, the pressing portion 90 of the torsion shaft 24 is separated from the electrode shaft 100 and is wound up. The start switch 114 is in an off state (step 206). Thereby, the motor 28 is maintained in a stopped state.

  The passenger who has pulled out the webbing 22 engages the tongue plate with the buckle and wears the seat belt. At this time, when the occupant engages the tongue plate with the buckle and the occupant is in the seat belt wearing state, the buckle switch 128 is turned on (step 208). Here, in the webbing take-up device 10, since the contact 130 is released when the buckle switch 128 is turned on, the pressing portion 90 of the torsion shaft 24 presses the tip of the electrode shaft 100 and the take-up switch 114 is turned on. However, the motor 28 is not energized, and the motor 28 is held in a stopped state.

  When the hand is released while the webbing 22 is being pulled out, the spiral spring 68 urges the spool 20 to rotate in the winding direction, but the relative rotation by the fan-shaped hole 88 formed in the rotating body 56. If the allowable range is not exceeded, the winding start switch 114 is not turned on, so that the webbing 22 is not wound by driving the motor 28.

  As described above, when the occupant is wearing the seat belt, the tongue plate and the buckle are engaged, and the buckle switch 128 is turned on (step 220). From here, when the occupant removes the seat belt, the engagement between the tongue plate and the buckle is released. As a result, the buckle switch 128 is turned off and the contact 130 is closed (step 222).

  When the engagement between the tongue plate and the buckle is released and the occupant loosens the webbing 22, the spool 20 rotates in the winding direction together with the torsion shaft 24 by the urging force of the spiral spring 68 (step 224). As a result, the torsion shaft 24 rotates relative to the rotating body 58 in the winding direction, and the pressing portion 90 moves in the fan-shaped hole 88 toward the tip of the electrode shaft 100. Thus, when the pressing portion 90 of the torsion shaft 24 abuts on the tip of the electrode shaft 100 and presses the electrode shaft 100, the electrode shaft 100 is moved against the urging force of the coil spring 106A.

  At this time, as shown in FIG. 5, the winding stop switch 116 is in an OFF state because the tip of the electrode shaft 102 is separated from the pressing portion 90 (Yes in step 224). As a result, the electrode shaft 100 moves so that the tip of the electrode shaft 100 is pushed out from the fan-shaped hole 88, the electrode 110 short-circuits the electrodes 78B and 78C, and turns on the winding start switch 114 (step 226). .

  In the power feeding circuit 122, when the winding start switch 114 is turned on while the buckle switch 128 and the winding stop switch 116 are turned off, the drive relay 124 is turned on and power feeding to the motor 28 is started. 28 is started (step 228).

  By driving the motor 28, the rotating body 56 of the switch gear 50 rotates in the winding direction, and the rotating body 56 rotates the spool 20 together with the torsion shaft 24 in the winding direction, so that the webbing 22 is wound around the spool 20 ( Step 230). At this time, since the motor 28 is driven at a substantially rated output, the winding stop switch 116 is kept off by the biasing force of the coil spring 106B. Further, in the power feeding circuit 122, when the driving relay 124 is turned on, the contact 132 is closed. Therefore, even if the winding start switch 114 is turned off, the winding stop switch 116 is turned off, so that the motor 28 is driven. Will continue.

  When the webbing 22 is wound in this way and the webbing 22 is fully retracted, the rotation of the spool 20 is stopped against the driving force of the motor 28 (step 232). Here, when the rotation of the spool 20 in the winding direction is stopped while the motor 28 is driven, the load (drive load) of the motor 28 increases, and the output of the motor 28 increases as the load increases. (Step 232).

  Thereby, the pressing force of the pressing portion 90 of the torsion shaft 24 by the electrode shaft 102 provided on the rotating body 56 increases, and the electrode shaft 102 is pushed out from the fan-shaped hole 88 against the urging force of the coil spring 106B. And the winding stop switch 116 is turned on (step 234).

  In the power feeding circuit 122, when the winding stop switch 116 is turned on, the drive relay 124 is turned off, and the power supply to the motor 28 is stopped. Thereby, in the webbing retractor 10, the drive of the motor 28 is stopped (step 236). Further, when the driving of the motor 28 is stopped, in the switch gear 50, the pressing portion 90 of the torsion shaft 24 is released from pressing the electrode shaft 102 by the driving force of the motor 28, and the electrode shaft 102 is released from the coil spring 106B. The spool 20 is moved by the rotation of the spool 20 in the pull-out direction (rotation in the direction of loosening the wound webbing 22) due to the urging force or the reaction when the motor 28 is stopped, and the winding stop switch 116 is turned off (step 238). .

  On the other hand, when the webbing 22 is being wound around the spool 20 by driving the motor 28, the output of the motor 28 increases even when the occupant grabs the webbing 22 or gets caught by the webbing 22 and the winding is temporarily stopped. Then, the winding stop switch 116 is turned on, and the driving of the motor 28 is stopped.

  At this time, the factor that prevents the webbing 22 from moving in the winding direction is removed by releasing the gripping webbing 22, and the spool 24 is rotated in the winding direction by the urging force of the spiral spring 68. Thus, the winding start switch 114 is turned on and the driving of the motor 28 is resumed.

  As described above, in the webbing take-up device 10, the take-up start switch 114 that is turned on when the spool 20 is rotated in the take-up direction by the urging force of the spiral spring 68 and the motor 28 that rotates the spool 20 in the take-up direction. A winding stop switch 116 that is turned on when the output increases, and the motor 28 is driven in response to ON / OFF of the winding start switch 114, the winding stop switch 116, and the buckle switch 128. An expensive component such as an ECU for controlling the drive of the motor 28 is not necessary.

  The switch gear 50 provided with the winding start switch 114 and the winding stop switch 116 can be provided in the driving force transmission mechanism 30 that transmits the driving force of the motor 28 to the spool 20. The complexity and the increase in the number of parts can be suppressed, and an increase in the load of the motor 28 when the webbing 22 is wound can be suppressed.

  In the first embodiment described above, the rotating body 56 is provided with the electrodes 78A to 78C, the electrodes 118A to 118C, the winding start switch 114, and the winding stop switch 116. The cover 58 may include the electrode shaft 110 and the coil spring 106A of the winding start switch 114 and the electrode shaft 102 and the coil spring 106B of the winding stop switch 116. In this case, the fan-shaped hole 88 (through hole 84) and the frame 108 may be formed in the cover 58.

The rotating body 56 is on the leg plate 18 side, the cover 58 is disposed on the opposite side of the rotating plate 56 from the leg plate 18, and the electrodes 110A of the electrode shafts 100 and 102 are connected to the cover 58 instead of the electrodes 78A to 78C. A structure may be provided in which a ring-shaped electrode 112 is in sliding contact with. In this case, the cover 58 can be freely rotated with respect to the torsion shaft 24 and the rotating body 56, and thus the cover 58 can be fixed. Therefore, wiring is connected to the cover 58 without using the brush electrodes 120 </ b> A to 120 </ b> C. be able to.
[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, the same parts and the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 8 shows a schematic configuration of a webbing take-up device 10A according to the second embodiment. In the webbing take-up device 10A, a switch gear 140 is provided in the take-up unit 26A in place of the switch gear 50 of the webbing take-up device 10. The switch gear 140 includes a rotating body 142. The rotating body 142 is formed in a substantially cylindrical shape with a shallow bottom, and is arranged so that the opening side is on the leg plate 18 side. The rotating body 142 is coaxial with the torsion shaft 24A and can rotate integrally.

  A spur gear portion 60 is formed on the outer peripheral portion of the rotating body 142, and the gear portion 60 is engaged with the two-stage gear 48. One end of a spiral spring 68 is locked to the shaft end portion 66 of the torsion shaft 24A. Thus, the webbing take-up device 10A is rotated in the take-up direction by the urging force of the spiral spring 68 and the driving force of the motor 28.

  9A and 9B show a schematic configuration of the rotating body 142 of the switch gear 140. FIG. 9A shows a schematic configuration of the rotating body 142 viewed from the leg plate 18 side, and FIG. 9B shows a main part of the rotating body 142 from a direction intersecting the axial direction of the rotating body 142. It is a schematic view.

  A boss portion 148 having a predetermined shape is formed on the rotating body 142 at the center of the surface of the bottom portion 146 on the leg plate 18 side (the front side in FIG. 9A). The boss portion 148 is formed with a circular hole portion 150 into which the torsion shaft 24 </ b> A is inserted such that the torsion shaft 24 </ b> A is relatively rotatable at a position that becomes the axial center portion of the bottom portion 146. The boss portion 148 is formed with fan-shaped hole portions 152 and 154 that are opened in a fan shape whose axis is the circular hole portion 150 side. The fan-shaped hole portions 152 and 154 are provided in pairs with the circular hole portion 150 interposed therebetween, and the respective axial centers are connected to the circular hole portion 150 and opened.

  The torsion shaft 24 </ b> A is provided with a substantially rectangular pressing portion 156 extending radially outward from the outer peripheral portion. The pressing portions 156 are provided in pairs with the axis of the torsion shaft 24 </ b> A interposed therebetween, one corresponding to the fan-shaped hole 152 formed in the boss 148 and the other corresponding to the fan-shaped hole 154. When the torsion shaft 24 </ b> A is inserted into the circular hole 150, one pressing part 156 is fitted into the fan-shaped hole 152, and the other pressing part 156 is fitted into the fan-shaped hole 154.

  Here, when the pressing portion 156 is fitted into the fan-shaped hole portions 152 and 154 that are opened in a fan shape at a predetermined angle, the torsion shaft 24A has a predetermined range (a range indicated by a two-dot chain line in FIG. 9A). It is possible to rotate relative to the rotating body 142 at an angle θ. Further, the torsion shaft 24A and the rotating body 142 rotate integrally with the pressing portion 156 of the torsion shaft 24A substantially in contact with the inner peripheral surfaces of the fan-shaped hole portions 152 and 154. Thereby, in the webbing take-up device 10A, the rotating body 142 can be rotated following the torsion shaft 24A.

  In the webbing take-up device 10A, when the torsion shaft 24A is rotated in the take-up direction, the pressing portion 156 in the fan-shaped hole 152 abuts on the inner peripheral surface 152A of the fan-shaped hole 152, and the fan-shaped hole The pressing portion 156 in 154 contacts the inner peripheral surface 154A of the fan-shaped hole portion 154, and the torsion shaft 24A and the rotating body 142 rotate integrally in the winding direction. In the webbing take-up device 10 </ b> A, the torsion shaft 24 </ b> A is rotated in the pull-out direction so that the pressing portion 156 in the fan-shaped hole 152 substantially contacts the inner peripheral surface 152 </ b> B of the fan-shaped hole 152. Thus, the pressing portion 156 in the fan-shaped hole 154 is substantially in contact with the inner peripheral surface 154B of the fan-shaped hole 154, and the torsion shaft 24A and the rotating body 142 rotate integrally in the drawing direction. .

  In the boss portion 148, a cut portion 158 is formed on the inner peripheral surface 152A side of the fan-shaped hole portion 152, and a cut portion 160 is formed on the inner peripheral surface 154B side of the fan-shaped hole portion 154. The notches 158 and 160 are formed so as to cut out the boss portion 148 from a predetermined position in the radial direction toward the outer side in the radial direction, thereby reducing the protruding height of a part of the boss portion 148. In the present embodiment, cut portions 158 and 160 are extended along the outer peripheries of the fan-shaped hole portions 152 and 154.

  On the other hand, the rotating body 142 is provided with a switch unit 162 on the surface of the bottom 146 on the leg plate 18 side. The switch unit 162 includes an operation member 164. The operation member 164 is substantially L-shaped, and arm portions 166 and 168 are formed in pairs. The arm portions 166 and 168 are connected at the ends opposite to the tip portions 166A and 168A so that the tip portions 166A and 168A on one side are directed in the same direction and the other side is linear. The operation member 164 is integrally formed with an operation lever portion 170 extending from the connecting portion of the arm portions 166 and 168 in the direction opposite to the distal end portions 166A and 168A.

  The operating member 164 has an end 166A of the arm 166 corresponding to the notch 158 of the fan-shaped hole 152 and an end 168A of the arm 168 corresponding to the notch 160 of the fan-shaped hole 154. Is directed outward in the radial direction of the rotating body 142.

  A pin 172 is erected on the bottom portion 146 of the rotating body 142, and the operation member 164 is inserted into a predetermined position of the operation lever portion 170 and supported so as to be swingable along the surface of the bottom portion 146. Is done.

  At this time, the operating member 164 is such that the tip 166A of the arm 166 protrudes from the notch 158 into the opening of the fan-shaped hole 152, and the tip 168A of the arm 168 extends from the notch 160 to the opening of the fan-shaped hole 154. The protruding lengths are the same. Further, the distal end portion 166A of the arm portion 166 and the distal end portion 168A of the arm portion 168 are not long in contact with the pressing portion 156 when the pressing portion 156 of the torsion shaft 24A is the central portion of the fan-shaped hole portions 152 and 154. It is said. Hereinafter, this position is set as an intermediate position of the operation member 164. In the present embodiment, the cut portions 158 and 160 are formed in the boss portion 148. However, the configuration is not limited to this as long as the boss portion 148 does not interfere with the arm portions 166 and 168 of the operation member 164. The configuration can be applied.

  As shown in FIGS. 9A and 9B, the operation lever portion 170 of the operation member 164 is a moving member in the vicinity of the end opposite to the connection portion with the arm portions 166 and 168. A slide member 174 is opposed. The slide member 174 is formed in a rectangular block shape and is arranged along a direction in which the longitudinal direction intersects the longitudinal direction of the operation lever portion 170. Further, as shown in FIG. 9B, the slide member 174 can move within a predetermined range along the longitudinal direction while being floated by a predetermined height with respect to the surface of the bottom portion 146 of the rotating body 142. It is supported by the bottom part 146 of the rotary body 142 so that it may become. 9A and 9B, the moving direction of the slide member 174 is indicated by an arrow C direction and an arrow D direction opposite to the arrow C direction.

  As shown in FIGS. 9A and 9B, the slide member 174 includes a locking portion 174 </ b> A directed to the surface opposite to the bottom 146 of the rotating body 142 and directed to the opposite side of the bottom 146. 174B are formed in pairs. In the slide member 174, the engaging portions 174A and 174B are set at a predetermined interval, and the operating lever portion 170 of the operating member 164 is disposed between the engaging portions 174A and the engaging portions 174B. Further, the operation member 164 is in contact with the locking portion 174A on the winding direction side with respect to the operation lever portion 170 at an intermediate position.

  Here, when the torsion shaft 24 </ b> A is relatively rotated in the winding direction with respect to the rotating body 142, the pressing portion 156 presses the distal end portion 166 </ b> A of the arm portion 166, so that the operation member 164 has the pin 172 as an axis. It is turned in the winding direction. The operation member 164 moves the slide member 174 in the direction of arrow D to a predetermined position by the operation lever portion 170 pressing the locking portion 174A of the slide member 174 by this rotation. Hereinafter, this position is referred to as a winding direction position of the slide member 174.

  When the torsion shaft 24A is rotated relative to the rotating body 142 in the pull-out direction, the pressing portion 156 presses the distal end portion 168A of the arm portion 168, so that the operation member 164 pulls in the pull-out direction about the pin 172. Is rotated. The operation member 164 causes the operation lever portion 170 to move away from the locking portion 174A of the slide member 174 and abut against the locking portion 174B by this rotation, and move the slide member 174 to a predetermined position in the direction of arrow C. Hereinafter, this position is referred to as a pull-out position of the slide member 174.

  As shown in FIG. 9B, the slide member 174 is provided with electrodes 176 and 178 on the surface of the rotating body 142 on the bottom 146 side. The electrodes 176 and 178 are formed by bending both ends of a strip-shaped conductive member so as to form a long hole when viewed from the width direction. One end of the conductive member is an electrode 176 and the other end is formed. The side is an electrode 178. Therefore, the electrode 176 and the electrode 178 are in an electrically connected state.

  An electrode 180 corresponding to the electrode 176 of the slide member 174 and an electrode 182 facing the electrode 178 are provided on the bottom 146 of the rotating body 142. Here, the electrode 176 and the electrode 180 are always in contact with each other when the slide member 174 is moved between the winding direction position and the drawing direction position. In addition, the electrode 178 and the electrode 182 are separated when the slide member 174 is moved to the pull-out direction position, but are brought into contact with each other when the slide member 174 moves to the take-up direction position to be in an electrically connected state. .

  As shown in FIG. 9A, one end of the tension coil spring 184 is locked to the operation lever portion 170 between the pin 172 and the slide member 174 in the operation member 164. The other end of the tension coil spring 184 is locked to the bottom 146 of the rotating body 142.

  The tension coil spring 184 generates a biasing force so as to hold the operation member 164 at an intermediate position. The tension coil spring 184 is pressed by the pressing portion 156 of the torsion shaft 24A, and the operation member 164 is rotated in the winding direction, thereby urging the operation lever portion 170 in the drawing direction. At this time, with the pressing force between the distal end portion 166A of the operating member 164 and the pressing portion 156, the pressing force due to the biasing force of the tension coil spring 184 is caused by the biasing force of the spiral spring 68 so that the torsion shaft 24A is wound in the winding direction. The pressing portion 156 is smaller than the force (pressing force) that presses the distal end portion 166A of the operation member 164 when rotating to the right.

  Note that the difference in the urging force between the spiral spring 68 and the tension coil spring 184 causes the operation member 164 to swing against the frictional resistance generated between the electrodes 176 and 180 and between the electrodes 178 and 182. It is only necessary to secure a difference that allows the slide member 174 to move.

  On the other hand, when the rotating body 142 is rotated in the winding direction, the distal end portion 168A of the operation member 164 presses the pressing portion 156 of the torsion shaft 24A in the winding direction. Thereby, when the spool 20 rotates in the winding direction together with the torsion shaft 24A, that is, when the motor 28 is driven at a substantially rated output, the urging force of the tension coil spring 184 causes the operation member 164 to rotate in the drawing direction. Be blocked.

  On the other hand, when the spool 20 does not rotate in the winding direction together with the torsion shaft 24A even though the motor 28 is driven, the output of the motor 28 increases from the rated output. In this case, a pressing force according to the output of the motor 28 acts between the pressing portion 156 of the torsion shaft 24 </ b> A and the distal end portion 168 </ b> A of the operation member 164.

  The pressing force due to the urging force of the tension coil spring 184 is smaller than the pressing force generated when the output of the motor 28 increases. As a result, the operation member 164 is pulled out against the urging force of the tension coil spring 184. Rotated in the direction. In the switch gear 140, when the operation member 164 rotates in the pull-out direction, the operation lever portion 170 of the operation member 164 moves the slide member 174 to the position in the pull-out direction. When the slide member 174 is moved in the pull-out direction, the electrode 178 and the electrode 182 are separated from each other, and the electrode 180 and the electrode 182 are electrically opened.

  As shown in FIGS. 8 and 9A, the rotating body 142 is provided with electrodes 186 and 188 formed in a ring shape having a predetermined width and a different diameter on the surface of the bottom 146 opposite to the leg plate 18. It has been. As shown in FIG. 9A, the electrodes 186 and 188 are such that the small-diameter electrode 186 is disposed on the center side of the rotating body 142, and the large-diameter electrode 188 is disposed outside the electrode 186 at a predetermined interval. Arranged and mounted coaxially with the rotating body 142. The electrode 186 is connected to the electrode 182, and the electrode 188 is connected to the electrode 180.

  As shown in FIG. 8, the winding unit 26 </ b> A is provided with a brush electrode 190 facing the electrode 186 and a brush electrode 192 facing the electrode 188. The brush electrodes 190 and 192 are in sliding contact with the electrodes 186 and 188 even when the rotating body 142 of the switch gear 140 is rotated, and the electrical connection state is maintained, and the electrodes 180 and 182 accompanying the movement of the slide member 174 are maintained. The open / closed state is taken out by the brush electrodes 190 and 192.

  As shown in FIG. 10, the brush electrode 190 is connected to the battery (+ B), and the brush electrode 192 is connected to the motor 28 via the contact 130 of the buckle switch 128. Accordingly, in the webbing take-up device 10A, when the buckle switch 128 is turned off, the slide member 174 is moved to the take-up direction position, and the electrode 176 and the electrode 180 of the switch unit 162 are connected. When the electrode 178 and the electrode 182 are connected and the switch unit 162 is turned on, electric power of a predetermined voltage is supplied to the motor 28 and the webbing 22 is wound around the spool 20.

  On the other hand, as shown in FIGS. 9A and 9B, in the switch unit 162, the distance between the locking portions 174A and 174B of the slide member 174 is the dimension (width) of the operation lever portion 170 of the operation member 164. Dimension) is larger.

  As a result, as shown in FIG. 11, in the switch unit 162, the movement of the slide member 174 is delayed with respect to the rotation of the operation member 164. That is, the slide member 174 moves with a predetermined delay with respect to the movement of the operation lever portion 170 of the operation member 164. Further, the interval between the locking portions 174A and 174B is determined until the operation member 164 swings from the position in the winding direction of the slide member 174 to the intermediate position and from the position in the pull-out direction of the slide member 174 to the intermediate position. The interval at which the slide member 174 does not move is set.

  Therefore, in the switch unit 162, the slide member 174 moves in the arrow D direction with a delay from the start of the rotation of the operation member 164 in the winding direction. Further, in the switch unit 162, the slide member 174 starts to move in the direction of arrow C with a delay from the start of the rotation of the operation member 164 in the pull-out direction. That is, in the switch unit 162, a predetermined hysteresis is provided between the rotation of the operation member 164 and the movement of the slide member 174, and the switch unit 162 is turned on / off with a delay from the rotation of the operation member 164.

  In the switch gear 140, the pressing portion 156 of the torsion shaft 24A is movable in the range of the angle θ within the fan-shaped hole portions 152 and 154. Thereby, the hysteresis between the rotation of the torsion shaft 24 </ b> A and the movement of the slide member 174 is further increased.

  In the webbing retractor 10A configured as described above, when the occupant does not wear the seat belt, the buckle switch 128 is turned off and the motor 28 is stopped. When the webbing 22 is pulled to attach the seat belt in this state, the spool 20 is rotated in the pull-out direction.

  At this time, in the switch gear 140, the torsion shaft 24 </ b> A is rotated in the pull-out direction, whereby the pressing portion 156 rotates the rotating body 142 in the pull-out direction while pressing the distal end portion 168 </ b> A of the arm portion 168. At this time, the operation member 164 is held at the intermediate position by the urging force of the tension coil spring 184, or is not rotated to the winding position even though it is rotated to the drawing position. Therefore, since the switch unit 162 is off, the motor 28 is maintained in a stopped state.

  Thereafter, when the occupant engages the tongue plate and the buckle to reach the seat belt wearing state, the buckle switch 128 is turned on, and the stopped state of the motor 28 is maintained.

  On the other hand, when removing the seat belt, the occupant releases the engagement between the tongue plate and the buckle. As a result, the buckle switch 128 is turned off (the contact 130 is closed). Further, the spool 20 is urged in the winding direction by the spiral spring 68, so that the engagement between the tongue plate and the buckle is released and the force for preventing the webbing 22 from moving in the winding direction is weakened. When released, the spool 20 is rotated in the winding direction by the urging force accumulated in the spiral spring 68.

  Here, in the switch gear 140, the torsion shaft 24 </ b> A rotates relative to the rotating body 142 in the winding direction and presses the distal end portion 166 </ b> A of the arm portion 166. Thereby, the operating member 164 is rotated in the winding direction against the urging force of the tension coil spring 184, the slide member 174 is moved to the winding direction position, and the switch unit 162 is turned on.

  The motor 28 is driven by supplying power when the switch unit 162 is turned on while the buckle switch 128 is turned off. As a result, the motor 28 rotates the spool 20 in the winding direction, and the webbing 22 is wound on the spool. At this time, when the spool 20 rotates in the winding direction, the motor 28 is driven at a substantially rated output, so that the operation member 164 is moved to an intermediate position and held at this position by the urging force of the compression coil spring 184. Is done. Therefore, the switch unit 162 is kept on and the driving state of the motor 28 is continued.

  Here, when the occupant is gripping the webbing 22 during the winding of the webbing 22 and the movement in the winding direction is prevented, the output of the motor 28 increases, and the operation member 164 rotates in the pull-out direction. The switch unit 162 is turned off. As a result, the motor 28 stops, but when the spool 20 is rotated in the winding direction by the urging force of the spiral spring 68 by releasing the hand from the webbing 22, the driving of the motor 28 is resumed.

  In the webbing take-up device 10A, when the webbing 22 is fully retracted, the spool 20 stops rotating in the take-up direction regardless of the drive of the motor 28. At this time, the load on the motor 28 increases and the output of the motor 28 increases. As a result, the pressing force between the pressing portion 156 of the torsion shaft 24A and the tip portion 168A of the operating member 164 increases, and the operating member 164 pressed by the pressing portion 156 of the torsion shaft 24A is attached to the tension coil spring 184. The switch unit 162 is turned off by rotating in the pull-out direction against the force and the slide member 174 reaching the pull-out position.

  When the switch unit 162 is turned off, the driving of the motor 28 is stopped. When the driving of the motor 28 is stopped, the operation member 164 is returned to the intermediate position by the urging force of the tension coil spring 184 and the like.

  Thus, in the webbing take-up device 10A, when the spool 20 is rotated in the take-up direction by the urging force of the spiral spring 68, it is turned on (contact closed), and the motor 28 is driven with a large output exceeding the rated output. A switch unit 162 that is turned off (contacts are opened) is provided, and the motor 28 is driven in accordance with on / off of the switch unit 162 and the buckle switch 128. As a result, in the webbing take-up device 10 </ b> A, as in the case of the webbing take-up device 10, expensive parts such as an ECU for controlling the drive of the motor 28 are unnecessary.

  In addition, since the webbing take-up device 10A directly supplies / cuts off the electrode to / from the motor 28 by opening / closing the contact, the supply / cut-off of electric power is further simplified as compared with the webbing take-up device 10 described above.

  Furthermore, in the webbing take-up device 10A, a phase difference is generated between the rotation of the operation member 164 of the switch unit 162 and the movement of the slide member 174. Therefore, the phase difference is smaller than that of the webbing take-up device 10. The mechanism to be generated is simplified.

  Also in the webbing take-up device 10A, the switch gear 140 provided with the rotating body 142 is provided on the torsion shaft 24A so that the driving force of the motor 28 is transmitted to the torsion shaft 24A (spool 20) via the switch gear 140. Therefore, the driving force transmission mechanism 30 when performing on / off control of the motor 28 is not complicated.

  In the embodiment described above, the switch gears 50 and 140 are provided on the torsion shafts 24 and 24A, and the driving force of the motor 28 is transmitted to the torsion shafts 24 and 24A via the switch gears 50 and 140. However, the present invention is not limited to this, and the torsion shafts 24, 24A are provided with gears in place of the switch gears 50, 140 so that the driving force of the motor 28 is transmitted to these gears. The switch gears 50 and 140 may be configured to rotate.

  In the present embodiment, the opening and closing of the contacts are taken out using the brush electrodes 120A to 120C facing the switch gear 50, and the opening and closing of the contacts are taken out using the brush electrodes 190 and 192 facing the switch gear 140. However, the mechanism for taking out the opening and closing of the contacts is not limited to this. For example, a cable that is formed in a spiral shape and can be rotated following the rotation on the connection side may be used. Thereby, it becomes possible to take out the opening and closing of the contact more reliably.

  Further, in the present embodiment, the winding start switch 114 and the winding stop switch 116 and the buckle switch 128 are used, or the motor 28 is driven / stopped using the switch unit 162 and the buckle switch 128. However, the present invention is not limited to this, and the present invention drives / stops the motor 28 by the winding start switch 114 and the winding stop switch 116 or the switch unit 162 without using the buckle switch 128. Also good.

  Further, in the present embodiment, the webbing take-up device 10, 10A has been described as an example, but the present invention has an arbitrary configuration in which the webbing is taken up by rotating the take-up shaft in the take-up direction by the driving force of the motor. It can be applied to a webbing take-up device.

10, 10A Webbing take-up device 20 Spool 22 Webbing 24, 24A Torsion shaft 28 Motor 30 Driving force transmission mechanism (driving force transmission means)
50, 140 switch gear (drive force transmission means)
56 Rotating body (driving force transmission means)
68 Spiral spring (winding mounting means)
88, 152, 154 Fan-shaped hole 90, 156 Pressing part 106A Coil spring 106B Coil spring 114 Winding start switch (rotation detection switch, first contact)
116 Winding stop switch (rotation detection switch, second contact)
122 Power supply circuit (power supply means)
128 buckle switch (mounting detection switch)
130 contacts (mounting release contacts)
162 Switch unit (rotation detection switch)
184 Tensile coil spring

Claims (4)

A spool that winds the webbing by locking the longitudinal base end side of the long webbing and rotating it in the winding direction;
Winding attachment biasing means for biasing the spool in the winding direction;
A motor that rotates the spool in the winding direction by supplying driving power;
Driving force transmitting means for transmitting the driving force of the motor to the spool;
Rotation of the spool in the winding direction provided in the driving force transmitting means, closed by rotating the spool in the winding direction by the winding attachment biasing means, and rotated by the driving force of the motor A rotation detection switch that includes a contact that is opened by the driving force of the motor that is increased when the motor is regulated;
Power supply means for starting the supply of the driving power to the motor when the contact of the rotation detection switch is closed, and stopping the supply of the driving power to the motor by opening the contact; ,
Including webbing take-up device.   It further includes a mounting release detection switch provided with a mounting release contact that is closed when the webbing mounting state for the occupant is released, and the power supply means is configured to close the mounting release contact and the rotation detection switch. The webbing take-up device according to claim 1, wherein the driving power is sometimes supplied to the motor. The driving force transmitting means includes a rotating body that is rotatable relative to the spool in a predetermined rotation angle range, and that rotates the spool in the winding direction by transmitting the driving force of the motor.
The rotation detection switch has a first contact that closes when the rotating body rotates due to rotation of the spool in the winding direction, and the rotating body winds the spool by the increased driving force of the motor. A second contact that is opened when rotating in the take-off direction,
The power supply means starts supplying the driving power to the motor when the mounting release contact and the second contact are closed and the first contact is closed, and the mounting release contact and Stopping supply of the driving power to the motor when at least one of the second contacts is released;
The webbing take-up device according to claim 2. A rotating body provided in the driving force transmitting means, capable of rotating relative to the spool in a predetermined rotation angle range, and rotating the spool in the winding direction by transmitting the driving force of the motor;
An operation member that is swung to a position where the spool and the rotating body rotate together by relative rotation of the spool with respect to the rotating body in the winding direction and the drawing direction;
A moving member that is provided in the rotation detection switch and is moved following the swing of the operation member to open and close the contact;
The webbing take-up device according to claim 1 or 2, comprising: