JP2012111419A - Webbing take-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a webbing take-up device that can take up and store the webbing to a spool with driving force of a motor, and can make a constitution for controlling the motor inexpensive.SOLUTION: In a clutch unit, if a clutch output side rotor 76 connected with the spool carries out relative rotation in a pullout direction to a clutch input side rotor 68, a first pawl 142 alienates from a pin 192 of a second pawl 178. If the clutch output side rotor 76 revolves in the winding direction from this condition, it alienates from a ratchet plate 202 with biasing force of return spring 184. Thereby, relative rotation of the spool to an output shaft of the motor is achieved, and driving of the motor can be started based on the relative rotation to the winding direction of the spool to the output shaft of the motor.

Description

  The present invention relates to a webbing take-up device that constitutes 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 the webbing take-up device (seat belt device) disclosed in Patent Document 1 below, the spool is rotated by the driving force of the motor, and the webbing (seat belt) is taken up and stored on the spool.

JP 2001-225720 A

  By the way, in the webbing take-up device disclosed in Patent Document 1, the motor is driven by detecting the falling of the electric signal at the buckle switch that occurs when the tongue is removed from the buckle, so-called “all storage”. The limit switch detects that the spool has rotated to the “state”, or detects that the time required for the spool to rotate to the “all stored state” has elapsed, thereby stopping the motor.

  In such a configuration, it is necessary to determine the drive start and stop timing of the motor with an expensive control device such as an ECU, and to control the drive of the motor based on the determination result. Becomes expensive.

  In consideration of the above-described facts, the present invention has an object to obtain a webbing take-up device that can wind and store a webbing on a spool with the driving force of the motor and that can be inexpensively configured to control the motor. is there.

  The webbing take-up device according to the first aspect of the present invention includes a spool that winds the webbing from the base end side in the longitudinal direction by locking the long webbing and rotating in the winding direction. An urging means for urging the spool in the winding direction; a forward driving force in a direction corresponding to the winding direction can be output from the output shaft; and the wearing of the webbing is released from the occupant's body; The spool rotates forward at a predetermined drive start timing when the spool rotates relative to the output shaft in the winding direction, and the output shaft moves relative to the spool in the winding direction in the forward driving state. It is interposed between the rotated motor at a predetermined drive stop timing, the output shaft of the motor and the spool, and operates when the forward rotation driving force is output from the motor. Roll The spool and the output shaft are coupled so as to be able to transmit power, and in this coupled state, a rotational force of a predetermined magnitude or more that rotates the output shaft relative to the spool in the normal rotation driving direction is applied to the output shaft. The output shaft is allowed to rotate relative to the spool when transmitted from the spool, and the spool further rotates in the winding direction after the spool rotates in the pulling direction opposite to the winding direction in the connected state. Clutch means for releasing the connection between the spool and the output shaft by rotating.

  In the webbing take-up device according to the first aspect, when the occupant pulls the webbing to mount the webbing, the spool rotates in the pulling-out direction while the webbing is pulled out from the spool. When the webbing of a length sufficient for wearing is pulled out and the webbing is put on the occupant's body, the biasing force of the biasing means rotates the spool in the winding direction until the slack of the webbing is removed to some extent. The rotation in the winding direction after the rotation of the spool in the pulling direction eliminates the connection between the spool and the output shaft of the motor in the clutch means (the connection capable of transmitting the rotational force between the spool and the output shaft). Is done. Therefore, in the webbing take-up device according to the present invention, when the occupant wears the webbing, the connection between the spool and the output shaft of the motor by the clutch means is canceled.

  When the occupant releases the webbing, the urging means rotates the spool in the winding direction. Here, in the webbing take-up device according to the present invention, the connection between the output shaft of the motor and the spool by the clutch means is canceled in this state. For this reason, when the biasing means rotates the spool in the winding direction with the biasing force, the spool rotates relative to the output shaft of the motor in the winding direction. When the wearing of the webbing is released from the body of such an occupant and the spool is further rotated relative to the output shaft of the motor in the winding direction, the motor is driven forward.

  When a normal driving force is output from the motor, the output shaft of the motor and the spool are connected by the clutch means, whereby the normal driving force of the motor is transmitted to the spool and the spool is rotated in the winding direction. As a result, the webbing is wound around the spool and the webbing is stored in the spool.

  When the webbing is wound on the spool in this way and the spool is in a so-called “full retracted state” where the spool cannot rotate further in the winding direction, the rotational force is applied from the output shaft to be rotated by the normal driving force of the motor to the clutch means. , The clutch means is allowed to rotate the output shaft relative to the spool, so that the output shaft of the motor rotates in the forward drive direction even if the rotation of the spool is restricted. The motor is stopped when a predetermined drive stop timing at which the rotation of the output shaft of the motor with respect to the spool occurs.

  Thus, in the webbing take-up device according to the present invention, the webbing can be taken up and stored on the spool by the normal rotation driving force of the motor. The urging force of the urging means can be reduced as long as the urging force is sufficient to rotate the spool in the winding direction to such an extent that relative rotation is generated between the urging force and the spool.

  Further, in the webbing take-up device according to the present invention, when the webbing is removed from the occupant's body, relative rotation in the take-up direction of the spool with respect to the output shaft of the motor can be caused. When in the “fully retracted state”, relative rotation in the forward drive direction of the output shaft of the motor with respect to the spool can be caused by the forward drive force of the motor. Such a relative rotation between the output shaft of the motor and the spool can occur when the webbing is removed from the occupant's body and after it is in the “full retracted state”. In the storage, the motor drive start and drive stop can be controlled based on the two relative rotations. For this reason, the structure of the control system for controlling the motor can be simplified, and the cost can be reduced.

  Even if the driving force of the motor is not used, the connection between the spool in the clutch means and the output shaft of the motor can be eliminated, thereby causing the spool to rotate relative to the output shaft of the motor when the webbing is removed from the occupant's body. Therefore, it is sufficient that the motor driving force can output only the forward driving force that rotates the spool in the winding direction. For this reason, control for switching the direction of the current flowing through the motor is not necessary, and in this sense, the configuration of the control system for controlling the motor can be simplified and the cost can be reduced.

  In addition, in order to release the connection between the output shaft of the motor and the spool in the clutch means, the spool must be rotated in the winding direction after the spool is rotated in the connected state between the motor output shaft and the spool. For this reason, basically, the connection state between the output shaft of the motor and the spool by the clutch means is maintained only when the "all stored state" is reached. In this state, friction in the driving force transmission mechanism between the output shaft of the motor and the spool, rotation resistance of the output shaft in the motor, and the like become resistance to rotation of the spool. For this reason, it is possible to prevent or effectively suppress the spool from rotating in the pull-out direction in the “all stored state”, and to prevent or suppress inadvertent pulling of the webbing.

  A webbing take-up device according to a second aspect of the present invention is the webbing retractor according to the first aspect of the present invention, wherein the clutch input-side rotating body that rotates by the forward driving force output from the motor and the spool A clutch output-side rotating body that is connected and capable of transmitting a rotational force to and from the spool, and is provided on the clutch input-side rotating body so as to be movable in a direction connected to the clutch output-side rotating body and in the opposite direction. At the same time, it is urged in a direction opposite to the direction in which it is connected to the clutch output side rotator. The rotation of the clutch input-side rotator is transmitted to the clutch output-side rotator, and the rotation of the clutch output-side rotator opposite to the forward drive direction is transmitted to the clutch. A connecting member that transmits to the force-side rotating body, and the clutch input-side rotating body rotates in the forward rotation driving direction to approach the connecting member and press the connecting member, and this pressing causes the connecting member to move to the clutch. A clutch operating member that is connected to the output side rotating body and is movable in a direction away from the connecting member by rotating the clutch input side rotating body in a direction opposite to the forward rotation driving direction. The clutch means is constituted.

  In the webbing take-up device according to the second aspect, when the occupant pulls the webbing to mount the webbing, the spool rotates in the drawing direction while the webbing is pulled out from the spool. As a result, the clutch output-side rotator connected to the spool rotates in the direction opposite to the normal rotation drive direction (hereinafter, this direction is referred to as “reverse rotation direction” for convenience). In this state, if the connecting member connects the clutch input side rotating body and the clutch output side rotating body, the rotation of the clutch output side rotating body is transmitted to the clutch input side rotating body via the connecting member, and the clutch input side rotation is performed. Rotate body in reverse drive direction.

  Thus, when the clutch input-side rotating body rotates in the reverse drive direction, the clutch operating member moves in a direction away from the coupling member. After this state, when the spool rotates in the winding direction, the connecting member moves in the direction opposite to the direction in which the connecting member is connected to the clutch output side rotating body by the action of the biasing force that biases the connecting member. The connection between the clutch input side rotator and the clutch output side rotator by the connecting member is canceled.

  In this way, the occupant pulls the webbing in order to wear the webbing, and further, the loosening of the webbing after the occupant wears the webbing on the body eliminates the slack of the webbing between the clutch input side rotating body and the clutch output side rotating body. When the occupant removes the webbing from the body, the relative rotation in the forward drive direction of the clutch output side rotating body with respect to the clutch input side rotating body with respect to the clutch input side rotating body, that is, the motor driving start timing Can be generated.

  On the other hand, when the forward drive force is output from the motor in a state where the connection between the clutch input side rotor and the clutch output side rotor is released, the clutch input side rotor is rotated in the forward drive direction together with the spool. . When the clutch input-side rotator rotates in the forward drive direction, the clutch operating member approaches the connecting member and presses the connecting member, and the connecting member is connected to the clutch output-side rotating body by this pressing. As described above, when the clutch input-side rotator and the clutch output-side rotator are connected via the connecting member, the rotation of the clutch input-side rotator in the forward drive direction is connected to the clutch output-side rotator via the connecting member. Thus, the rotating body of the clutch output side can be rotated in the forward rotation driving direction, and the spool can be further rotated in the winding direction to wind the webbing around the spool.

  The webbing take-up device according to a third aspect of the present invention is the webbing take-up device according to the first or second aspect, wherein the rotational force is transmitted by friction between a predetermined portion between the output shaft and the spool. And a clutch including a friction clutch that allows rotation of the output shaft relative to the spool when a relative rotational force of the output shaft relative to the spool in the forward rotation driving direction exceeds the friction. Means.

  In the webbing take-up device described in claim 3, the clutch means includes a friction clutch, and the rotation of the output shaft of the motor is transmitted to the spool via the friction clutch. When the spool winds up the webbing due to the normal rotation driving force of the motor, it becomes “all retracted state” and the rotation of the spool in the winding direction is restricted, and in this state, the normal rotation driving force is further output from the motor. When the relative rotational force on the output shaft side with respect to the spool side exceeds the maximum dynamic friction force in the friction clutch, the output shaft side rotates relative to the spool side in the friction clutch, and this causes the motor output shaft to rotate forward with respect to the spool. Rotate relative to direction. The relative rotation generated in this way can generate a motor drive stop timing, and the motor can be stopped.

  A webbing retractor according to a fourth aspect of the present invention is the webbing take-up device according to the first aspect of the present invention, wherein the webbing take-up device is electrically connected to the motor in the first aspect of the present invention. A mounting release detection switch that becomes electrically conductive when the mounting state of the webbing is canceled, and is electrically connected to the motor and interlocked with the relative rotation in the winding direction of the spool with respect to the output shaft. A relative rotation detection switch that is in an electrical conduction state and releases the conduction state in conjunction with a relative rotation of the output shaft with respect to the spool in the forward rotation drive direction, the mounting release detection switch, The mounting release detection switch and the relative rotation detection switch are connected to the motor so that the motor is driven to rotate forward when both of the relative rotation detection switches are turned on. And continue to.

  In the webbing take-up device according to the fourth aspect, when the occupant releases the wearing of the webbing, the urging means rotates the spool in the take-up direction and the attachment release detecting switch is turned on. Next, when the spool is rotated in the winding direction by the biasing force of the biasing means, when the relative rotation in the winding direction of the spool with respect to the motor output shaft occurs, the relative rotation detection switch operates in conjunction with this relative rotation. Then, the relative rotation detection switch becomes conductive. As described above, when both the mounting release detection switch and the relative rotation detection switch are in the conductive state, the motor is energized and the motor is driven to rotate forward. The clutch means connects the output shaft of the motor and the spool by forward rotation of the motor, and the forward rotation driving force of the motor is transmitted to the spool, whereby the spool rotates in the winding direction and winds the webbing.

  On the other hand, when the spool rotates in the take-up direction until the “all retracted state” and the output shaft rotates relative to the spool in the normal driving direction due to the normal driving force output from the spool in this state, the relative rotation is detected. The conduction in the switch is interrupted. Even if the mounting release detection switch is in a conductive state, the conduction in the relative rotation detection switch is canceled, so that the power supply to the motor is cut off and the motor stops.

  Thus, in the webbing take-up device according to the present invention, when both the mounting release detection switch and the relative rotation detection switch are turned on, the motor is energized, and at least one of the mounting release detection switch and the relative rotation detection switch is turned on. When the is released, the power supply to the motor is cut off. For this reason, in the webbing take-up device according to the present invention, for example, a battery mounted on a vehicle, a disengagement detection switch, a relative rotation detection switch, and a motor may be electrically connected in series. The circuit configuration can be simplified.

  As described above, the webbing take-up device according to the present invention can store the webbing on the spool by the driving force of the motor, and can further reduce the configuration for controlling the motor.

It is a disassembled perspective view of a structure of the principal part of the webbing take-up device according to the first embodiment. It is a disassembled perspective view of the clutch means which comprises the webbing winding device concerning a 1st embodiment. It is a front view which shows the initial state of a clutch means. FIG. 4 is a front view corresponding to FIG. 3, showing a state where the clutch output-side rotator is rotated in the pull-out direction from the initial state. FIG. 5 is a front view corresponding to FIG. 4 showing a state in which the clutch output-side rotator is rotated forward from the state shown in FIG. 4 and the connection between the clutch input-side rotator and the clutch output-side rotator is released. FIG. 6 is a front view corresponding to FIG. 5, showing a state in which the clutch input means rotates forward from the state shown in FIG. 5 and the clutch operating member approaches the connecting member. It is a disassembled perspective view of the rotation detection switch which comprises the webbing winding device concerning a 1st embodiment. It is a front view which shows the initial state of a rotation detection switch. FIG. 9 is a front view corresponding to FIG. 8 showing a state in which the switch second rotating body rotates relative to the switch first rotating body in the pull-out direction. FIG. 9 is a front view corresponding to FIG. 8 illustrating a state in which the switch first rotating body rotates relative to the switch second rotating body in the normal rotation driving direction. It is a schematic circuit diagram which shows the structure of the control system of a motor. It is a disassembled perspective view which shows the part of the mechanical structure of the rotation detection switch in the webbing take-up device according to the second embodiment. It is a side view of the principal part of the rotation detection switch in 2nd Embodiment. It is a circuit diagram which shows roughly the circuit structure of the rotation detection switch in 2nd Embodiment.

  Next, each embodiment of the present invention will be described with reference to FIGS.

<Configuration of First Embodiment>
The structure of the principal part of the webbing take-up device 10 according to the first embodiment is shown in an exploded perspective view in FIG.

  As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 includes, for example, a plate-like back plate 14 whose thickness direction is along the vehicle width direction and whose width direction is generally along the vehicle front-rear direction. Leg plates 16 and 18 extend from one end in the width direction of the back plate 14 toward one side in the thickness direction of the back plate 14. Each of the leg plates 16 and 18 is formed in a plate shape whose thickness direction is along the width direction of the back plate 14, and a spool 20 is provided between the leg plate 16 and the leg plate 18. The spool 20 has a substantially cylindrical shape whose axial direction is along the opposing direction of the leg plate 16 and the leg plate 18. A longitudinal direction proximal end side of a webbing 22 formed in a long band shape is locked to the spool 20. The webbing 22 is wound around the outer peripheral portion of the spool 20 from the longitudinal base end side, and the tip end side is pulled out from the spool 20 to the upper side of the vehicle.

  On the outside of the above-described leg plate 16 (on the side opposite to the leg plate 18 of the leg plate 16), when the vehicle suddenly decelerates or when the spool 20 suddenly rotates in the winding direction when the spool 20 winds up the webbing 22. A lock mechanism that operates to restrict rotation of the spool 20 in the pulling direction opposite to the winding direction, or a pretensioner that operates when the vehicle suddenly decelerates and forcibly rotates the spool 20 in the winding direction. For example, the end of the spool 20 on the leg plate 16 side is directly attached to the housing of the lock mechanism integrally attached to the leg plate 16 or indirectly through an energy absorbing member called a torsion shaft or the like. It is supported rotatably. In addition, since these lock mechanisms and pretensioner mechanisms are basically known techniques, detailed descriptions thereof are omitted.

  On the other hand, a winding unit 30 is provided on the outer side of the above-described leg plate 18 (on the side opposite to the leg plate 16 of the leg plate 18). The winding unit 30 includes a motor 32, a driving force transmission mechanism 34, a clutch unit 36 as a clutch means, a relative rotation detection switch 38 as a rotation detection switch, a unit case 40, and a spring unit 44.

(Configuration of unit case 40)
The unit case 40 includes a case main body 46. The case main body 46 is formed in a concave shape that opens toward the opposite side of the leg plate 18, and the motor 32, the driving force transmission mechanism 34, the clutch unit 36, and the relative rotation detection switch 38 are accommodated therein. A cover 48 is provided on the open end side of the case body 46, and the case body 46 is closed by the cover 48.

(Configuration of motor 32)
The motor 32 is provided in a motor housing portion 50 formed in the case main body 46. The motor housing portion 50 includes an output shaft 52 whose axial direction is set in the same direction as the axial direction of the spool 20 described above. The output shaft 52 has a distal end side facing away from the leg plate 18 from the main body portion of the motor housing portion 50, and a gear 54 constituting the driving force transmission mechanism 34 is located on the distal end side of the output shaft 52 with respect to the output shaft 52. It is attached coaxially and integrally.

(Configuration of the driving force transmission mechanism 34)
A two-stage gear 56 constituting the driving force transmission mechanism 34 is provided on the outer side in the rotational radius direction of the gear 54. The two-stage gear 56 has a large-diameter gear portion having a larger number of teeth than the gear 54 and a smaller-diameter portion than the large-diameter gear portion, and is opposed to the large-diameter gear portion on the bottom side of the case body 46 rather than the large-diameter gear portion. And a small-diameter gear portion formed coaxially and integrally. Corresponding to the two-stage gear 56, a support shaft 58 is provided inside the case body 46. The support shaft 58 has an axial direction that is the same as the axial direction of the spool 20. One end of the support shaft 58 is supported by the bottom of the case body 46 and the other end is supported by the cover 48. The two-stage gear 56 is rotatably supported coaxially with respect to the support shaft 58, and the large-diameter gear portion meshes with the gear 54.

  A two-stage gear 60 constituting the driving force transmission mechanism 34 is provided on the outer side in the rotational radial direction of the small-diameter gear part constituting the two-stage gear 56. The two-stage gear 60 has a large-diameter gear section having a larger number of teeth than the small-diameter gear section of the two-stage gear 56 and a smaller number of teeth than the large-diameter gear section, and is located closer to the bottom of the case body 46 than the large-diameter gear section. The small-diameter gear portion is formed coaxially and integrally with the large-diameter gear portion. Corresponding to the two-stage gear 60, a support shaft 62 is provided inside the case body 46. The support shaft 62 has an axial direction that is the same as the axial direction of the spool 20. One end of the support shaft 62 is supported by the bottom of the case body 46 and the other end is supported by the cover 48. The two-stage gear 60 is rotatably supported coaxially with respect to the support shaft 62, and the large-diameter gear portion meshes with the small-diameter gear portion of the two-stage gear 56.

  A two-stage gear 64 constituting the driving force transmission mechanism 34 is provided on the outer side in the rotational radial direction of the small-diameter gear part constituting the two-stage gear 60. The two-stage gear 64 has a large-diameter gear section having a larger number of teeth than the small-diameter gear section of the two-stage gear 56 and a smaller number of teeth than the large-diameter gear section, and is located closer to the opening side of the case body 46 than the large-diameter gear section. The small-diameter gear portion is formed coaxially and integrally with the large-diameter gear portion. A support shaft 66 is provided inside the case body 46 corresponding to the two-stage gear 64. The support shaft 66 has an axial direction that is the same as the axial direction of the spool 20. One end of the support shaft 66 is supported by the bottom of the case body 46 and the other end is supported by the cover 48. The two-stage gear 64 is rotatably supported coaxially with respect to the support shaft 66, and the small-diameter gear portion meshes with the small-diameter gear portion of the two-stage gear 56.

  The large-diameter gear portion of the two-stage gear 64 meshes with an input gear portion 70 formed on the clutch input-side rotator 68 that constitutes the clutch unit 36, and the switch second rotator that constitutes the relative rotation detection switch 38. It meshes with a gear formed on the outer periphery of 72.

  On the other hand, the driving force transmission mechanism 34 includes a two-stage gear 74. The two-stage gear 74 has a large-diameter gear portion that meshes with a clutch output gear 78 that constitutes the clutch output-side rotator 76 of the clutch unit 36, and has a smaller number of teeth than the large-diameter gear portion, and a case body that is smaller than the large-diameter gear portion. The small-diameter gear portion is formed coaxially and integrally with the large-diameter gear portion on the opening side of 46. The two-stage gear 74 is rotatably supported coaxially with respect to the support shaft 66 described above.

  A two-stage gear 80 constituting the driving force transmission mechanism 34 is provided outside the small-diameter gear part constituting the two-stage gear 74 in the rotational radial direction. The two-stage gear 80 has a large-diameter gear section having a larger number of teeth than the small-diameter gear section of the two-stage gear 74 and a smaller number of teeth than the large-diameter gear section, and is located closer to the opening side of the case body 46 than the large-diameter gear section. The small-diameter gear portion is formed coaxially and integrally with the large-diameter gear portion. The two-stage gear 80 is rotatably supported coaxially with respect to the support shaft 62 described above, and the large-diameter gear portion meshes with the small-diameter gear portion of the two-stage gear 74.

  A gear 82 constituting the driving force transmission mechanism 34 is provided on the outer side in the rotational radial direction of the small-diameter gear portion constituting the two-stage gear 80. A support shaft 84 is provided inside the case main body 46 so as to correspond to the gear 82. The support shaft 84 has an axial direction that is the same as the axial direction of the spool 20, and one end thereof is supported by the bottom of the case body 46 and the other end is supported by the cover 48. The gear 82 is rotatably supported coaxially with respect to the support shaft 84, meshes with the small-diameter gear portion of the two-stage gear 80, and constitutes the relative rotation detection switch 38 of the switch first rotating body 86. It meshes with a gear formed on the outer periphery.

  Here, in the present embodiment, as described above, the driving force output from the motor 32 is transmitted to the switch second rotating body 72 of the relative rotation detection switch 38 to rotate the switch second rotating body 72 and the clutch. The switch first rotating body 86 is transmitted to the switch first rotating body 86 of the relative rotation detection switch 38 via the unit 36 and rotates. However, the switch second rotating body 72 by the driving force output from the motor 32 is used. And the rotation direction of the switch first rotating body 86 are the same, and the rotation speed of the switch second rotating body 72 and the rotation speed of the switch first rotating body 86 are the same or the switch second rotating body 72 The gear ratio or the like in the driving force transmission mechanism 34 is set so that the rotational speed of the switch first rotating body 86 is slightly faster than the rotational speed.

(Configuration of clutch unit 36)
Next, the configuration of the clutch unit 36 that is one of the characteristic configurations of the webbing take-up device 10 will be described.

  The clutch unit 36 includes the clutch input side rotating body 68 described above. As shown in FIG. 3, the clutch input-side rotator 68 includes a disk-shaped first bottom wall portion 92, and the input gear portion 70 described above is coaxially and integrally formed with the first bottom wall portion 92. Is formed. An annular first peripheral wall portion 94 is formed on the outer peripheral portion of the first bottom wall portion 92 so as to extend toward the bottom side of the case body 46, and the inner side of the first peripheral wall portion 94 is the first clutch plate. The housing portion 96 is provided.

  A second bottom wall 98 extends from the end of the first peripheral wall 94 opposite to the first bottom wall 92 toward the radially outer side of the first peripheral wall 94. The outer peripheral shape of the second bottom wall portion 98 is a circular shape coaxial with the first bottom wall portion 92 and the first peripheral wall portion 94. An annular second peripheral wall portion 100 is formed on the outer peripheral portion of the second bottom wall portion 98 so as to extend toward the bottom side of the case body 46, and the inner side of the second peripheral wall portion 100 is the second clutch. The plate accommodating portion 102 is used.

  A circular hole 104 is formed in the first bottom wall portion 92 of the clutch input side rotating body 68. The circular hole 104 is coaxially formed with respect to the first bottom wall portion 92, and one end thereof opens on the first clutch plate housing portion 96 side of the first bottom wall portion 92, and the other end thereof is the input gear portion 70. Opening is made at the end surface opposite to the first bottom wall portion 92. A stepped shaft 106 whose axial direction is the same as the axial direction of the spool 20 passes through the circular hole 104. The stepped shaft 106 includes a cylindrical base 108.

  A cylindrical large-diameter shaft portion 110 whose outer diameter is smaller than the outer diameter of the base 108 is formed coaxially and integrally with the base 108 on the end surface of the base 108 on the bottom side of the base 108. The clutch input side rotating body 68 is rotatably supported by the large diameter shaft portion 110 of the stepped shaft 106. On the end surface of the large-diameter shaft portion 110 opposite to the base portion 108, a cylindrical medium-diameter shaft portion 112 whose outer diameter dimension is smaller than that of the large-diameter shaft portion 110 is formed with respect to the large-diameter shaft portion 110. Are formed coaxially and integrally. Further, on the end surface of the medium diameter shaft portion 112 opposite to the large diameter shaft portion 110, a cylindrical small diameter shaft portion 114 whose outer diameter dimension is smaller than that of the medium diameter shaft portion 112 is a medium diameter shaft portion. The small-diameter shaft portion 114 is supported at the bottom of the case body 46 by being coaxially and integrally formed with respect to 112.

  On the other hand, the clutch unit 36 includes a first clutch plate 120. The first clutch plate 120 includes a cylindrical boss 124 that constitutes the first friction clutch portion 122. The inner diameter dimension of the boss 124 is set to be smaller than the outer diameter dimension of the large-diameter shaft portion 110 constituting the stepped shaft 106 and larger than the outer diameter dimension of the medium-diameter shaft portion 112. The shaft portion 112 passes through the boss 124. A friction spring 126 that constitutes the first friction clutch portion 122 together with the boss 124 is provided inside the boss 124. The friction spring 126 is formed in a coil shape or a ring shape in which the central axis direction is the same as the axial direction of the boss 124.

  The friction spring 126 is penetrated by the medium diameter shaft portion 112 of the stepped shaft 106. Therefore, the friction spring 126 is interposed between the inner peripheral portion of the boss 124 and the outer peripheral portion of the medium diameter shaft portion 112. Become. The boss 124 is integrally connected by friction between the inner peripheral portion of the boss 124 and the friction spring 126 and friction between the outer peripheral portion of the medium diameter shaft portion 112 and the friction spring 126. When a rotational force exceeding the frictional force acts on the boss 124 (that is, the first clutch plate 120), the boss 124 (that is, the first clutch plate 120) rotates around the medium diameter shaft portion 112.

  Further, the first clutch plate 120 includes a support plate 132. The support plate 132 has a disk shape whose outer diameter is smaller than the inner diameter of the first peripheral wall portion 94, and is formed coaxially and integrally with the boss 124 on the end surface of the boss 124 on the bottom side of the case body 46. ing. A circular hole 134 having an inner diameter dimension equal to the inner diameter dimension of the boss 124 is formed in the center of the support plate 132. The circular hole 134 is connected to the inside of the boss 124, and the medium diameter shaft portion 112 passes through the circular hole 134. A shaft 136 is formed on the surface of the support plate 132 opposite to the boss 124.

  The shaft 136 is formed at a position spaced apart from the circular hole 134 in the radial direction of the support plate 132. A first pawl 142 as a clutch operating member is provided on the opposite side of the support plate 132 from the boss 124. The first pawl 142 includes a plate-like base portion 144. The base 144 is formed with a circular hole 146 whose inner diameter is slightly larger than the outer diameter of the shaft 136. The shaft 136 passes through the circular hole 146, and the first pawl 142 is supported by the shaft 136 so as to be rotatable around the shaft 136.

  Further, a pawl spring 152 as a clutch operating member formed of a rod-like member having spring properties is provided on the opposite side of the support plate 132 from the boss 124. The pawl spring 152 includes an insertion portion 154. The insertion portion 154 is inserted into a small hole opened at the tip of the shaft 136 so as to be rotatable around an axis whose axial direction is the same as the axial direction of the stepped shaft 106. A pawl operating portion 156 is formed continuously from one end of the insertion portion 154 in the longitudinal direction. The pawl operating portion 156 is formed in a rod shape whose longitudinal direction is substantially parallel to the end surface of the support plate 132.

  A flat pressed portion 158 is formed on the first pawl 142 corresponding to the pawl spring 152. A vertical wall portion 160 and a vertical wall portion 162 extend from the pressed portion 158 toward the bottom side of the case main body 46. The vertical wall portion 160 is located on the side of the pawl operation portion 156 that is perpendicular to both the axial direction of the stepped shaft 106 and the longitudinal direction of the pawl operation portion 156, and the vertical wall portion 162 is It is located on the opposite side to the vertical wall 160 through the operation unit 156. When the pawl spring 152 rotates about the insertion portion 154, the pawl operating portion 156 presses the vertical wall portion 160 or the vertical wall portion 162, whereby the first pawl 142 rotates about the shaft 136.

  A second clutch plate 170 is provided between the first clutch plate 120 and the clutch output side rotating body 76. The second clutch plate 170 includes a support plate 172. The support plate 172 is formed in a disk shape whose outer diameter is smaller than the inner diameter of the second peripheral wall portion 100. A circular hole 174 having an inner diameter smaller than the outer diameter of the medium-diameter shaft portion 112 and slightly larger than the outer diameter of the small-diameter shaft portion 114 is formed at the center of the support plate 172. The small diameter shaft portion 114 of the stepped shaft 106 passes therethrough. As a result, the second clutch plate 170 is rotatably supported by the small diameter shaft portion 114 on the side opposite to the first bottom wall portion 92 of the first clutch plate 120.

  Corresponding to the support plate 172 supported by the shaft 176, a sliding contact portion 177 is attached to the pawl spring 152 on the side opposite to the insertion portion 154 of the pawl operation portion 156. The sliding contact portion 177 is formed in a cylindrical shape whose axial direction is substantially the same as the axial direction of the stepped shaft 106, and one end in the axial direction (on the support plate 172 side) is the support plate 132 of the support plate 172. When the support plate 172 rotates (forward) in one direction around the small-diameter shaft portion 114 (in the direction of arrow A in FIG. 3), the space between the slide contact portion 177 and the support plate 172 is When the sliding contact portion 177 rotates around the insertion portion 154 in the direction of arrow B in FIG. 3 and the support plate 172 rotates (reverses) around the small-diameter shaft portion 114 (in the direction of arrow B in FIG. 3). The sliding contact portion 177 rotates in the direction of arrow A in FIG. 3 around the insertion portion 154 due to friction between the sliding contact portion 177 and the support plate 172.

  A shaft 176 is provided on the opposite side of the support plate 172 from the first clutch plate 120. The shaft 176 has an axial direction that is the same as the axial direction of the stepped shaft 106, and is formed to protrude from the support plate 172 outside the circular hole 174 in the radial direction of the support plate 172. The shaft 176 passes through a through hole 180 formed in a second pawl 178 as a connecting member, and the shaft 176 supports the second pawl 178 in a rotatable manner.

  Further, a spring mounting pin 182 is formed on the support plate 172 on the side of the second pawl 178, and a return spring 184 is mounted on the spring mounting pin 182. Further, a spring locking portion 186 is formed on the support plate 172 on the opposite side of the shaft 176 through the spring mounting pin 182, and one end of the return spring 184 is locked to the spring locking portion 186. . The tip of the return spring 184 is locked to a spring locking portion 188 formed on the second pawl 178, and the return spring 184 is attached around the shaft 176 so that the spring locking portion 188 approaches the circular hole 174. It is fast.

  Further, a through hole 190 is formed in the support plate 172 on the opposite side of the return spring 184 through the shaft 176, and the second pawl 178 is formed on the opposite side of the spring locking portion 188 through the through hole 180. The formed pin 192 passes through the through hole 190 and protrudes toward the first clutch plate 120. The first pawl 142 described above corresponding to the pin 192 is formed with an operation portion 194 whose outer peripheral shape is bent in a bowl shape, and the vertical wall portion 160 is pressed against the pressed portion 158 of the pawl spring 152, and the shaft When the first pawl 142 rotates around 136, the operating portion 194 engages with the pin 192 to press the pin 192, and rotates the second pawl 178 around the shaft 176 against the biasing force of the return spring 184. Let

  The support plate 172 includes a second friction clutch portion 196 as a friction clutch. The second friction clutch portion 196 includes a pair of friction springs 198 attached to the support plate 172 so as to face each other through the circular holes 174 of the support plate 172. These friction springs 198 are provided with sliding contact portions 200. The sliding contact portion 200 is curved with the center side of the support plate 172 as the center of curvature, and at least a part of each sliding contact portion 200 is located on the outer side of the support plate 172 in the radial direction of the support plate 172. Yes.

  In a state where the support plate 172 is disposed inside the second clutch plate housing portion 102, the outer peripheral portion of the support plate 172 is separated from the inner peripheral portion of the second peripheral wall portion 100, and the outer peripheral portion of the support plate 172 is the second peripheral wall. There is no sliding contact with the inner periphery of the portion 100. However, since the sliding contact portion 200 is in sliding contact with the inner peripheral portion of the second peripheral wall portion 100 in this state, the clutch input-side rotator 68 rotates due to friction between the sliding contact portion 200 and the second peripheral wall portion 100. Then, the support plate 172 rotates together with the clutch input side rotating body 68.

  On the opposite side of the support plate 172 from the first clutch plate 120, the above-described clutch output side rotating body 76 is provided. The clutch output side rotator 76 includes a ratchet plate 202. The ratchet plate 202 is integrally formed coaxially with the clutch output gear 78 constituting the clutch output side rotator 76, and the second pawl 178 rotates around the shaft 176 against the urging force of the return spring 184. Then, in the second pawl 178, the engaging portion 204 formed on the opposite side of the spring locking portion 188 meshes with the external teeth of the ratchet plate 202, and the second clutch plate 170 is rotated in the direction of arrow A in FIG. The clutch output side rotating body 76 can be rotated in the direction of arrow A in FIG.

(Configuration of relative rotation detection switch 38)
Next, the configuration of the relative rotation detection switch 38 that is one of the characteristic configurations of the webbing take-up device 10 together with the clutch unit 36 will be described.

  The relative rotation detection switch 38 includes the switch second rotating body 72 and the switch first rotating body 86 described above. As shown in FIG. 7, the switch first rotating body 86 is formed in a shallow bottomed cylindrical shape that opens toward the opposite side of the bottom of the case body 46, and the outer periphery of the switch has a flat tooth. Teeth are formed. A boss 224 is formed inside the switch first rotating body 86 and at the center of the bottom 222 of the switch first rotating body 86.

  The outer periphery of the boss 224 is circular, and is formed coaxially and integrally with the disc-shaped bottom 222. The boss 224 is formed with a fitting insertion hole 226 that penetrates in the same direction as the axial direction of the spool 20. The inner peripheral shape of the insertion hole 226 is a non-circular shape such as a polygonal shape, a star shape, or an elliptical shape. For example, an insertion portion formed on the leg plate 18 side portion of the torsion shaft described above is inserted, The switch first rotating body 86 is connected to the torsion shaft, and hence the spool 20 in a state in which the relative rotation with respect to the torsion shaft and thus the spool 20 is substantially impossible.

  On the other hand, the switch second rotating body 72 is formed in a shallow bottomed cylindrical shape opened toward the bottom side of the case main body 46, and flat teeth are formed on the outer periphery thereof. A circular hole 234 whose inner diameter is slightly larger than the outer diameter of the boss 224 is formed in the bottom 232 of the switch second rotating body 72. The circular hole 234 is coaxially formed with respect to the bottom 232, and the boss 224 of the switch first rotating body 86 penetrates the circular hole 234, and the boss 224 supports the switch second rotating body 72 in a freely rotatable manner. For this reason, the switch second rotating body 72 and the switch first rotating body 86 can be relatively rotated coaxially.

  An outer ring groove 236 is formed on the outer surface of the bottom portion 232 (the surface opposite to the bottom portion 222). The outer ring groove 236 is formed in an annular shape coaxial with the bottom portion 232, and an outer ring terminal 238, which is one of a pair of annular contacts, is provided inside the outer ring groove 236. The outer ring terminal 238 is formed by making a conductive plate material such as copper into a ring shape, and is integrally attached to the bottom portion 232 inside the outer ring groove 236, and integrally with the switch second rotating body 72. It is designed to rotate.

  Further, an inner ring groove 240 is formed inside the outer ring groove 236 on the outer surface of the bottom portion 232. The inner ring groove 240 has an annular shape smaller in diameter than the outer ring groove 236 and is formed coaxially with the bottom portion 232, and an inner ring terminal 242 that is the other of the pair of annular contacts is provided on the inner side thereof. . The inner ring terminal 242 is formed by making a conductive plate material such as copper into a ring shape, and is integrally attached to the bottom portion 232 inside the inner ring groove 240, and integrally with the switch second rotating body 72. It is designed to rotate.

  On the other hand, an outer contact 244 formed of a conductive plate material such as copper is provided on the opposite side of the switch second rotating body 72 from the switch first rotating body 86. The outer contact 244 includes a plurality of frame portions 246. Each of the frame portions 246 is formed in a rectangular frame shape, and a sliding piece 248 extends from the inner peripheral portion of each frame portion 246. The sliding piece 248 is formed in a rectangular flat plate shape, and is bent toward the switch second rotating body 72 around the base end portion in the longitudinal direction, which is a connection portion with the frame portion 246, and the distal end portion thereof is the outer ring groove 236. It enters inside and is in sliding contact with the outer ring terminal 238. The outer contact 244 includes one or more connection pieces 250, and connects the frame portions 246 in a row.

  Further, an inner contact 252 formed of a conductive plate material such as copper is provided on the opposite side of the switch second rotating body 72 from the switch first rotating body 86. The inner contact 252 includes a plurality of sliding pieces 254. The longitudinal base ends of these sliding pieces 254 are connected by 0256. These outer contact 244 and inner contact 252 are fixed to the bottom of the cover 48 inside the cover 48.

  As shown in the schematic circuit diagram shown in FIG. 11, the outer contact 244 extends from the outside of the cover 48 (that is, the end of the outer contact 244 opposite to the sliding contact portion with the outer ring terminal 238 in FIG. 1). Is connected to one fixed contact of a buckle switch 262 as a mounting release detection switch. The buckle switch 262 is provided on a buckle (not shown) that constitutes a seat belt device together with the webbing retractor 10, and a tongue (not shown) provided on the webbing 22 in a state where the webbing 22 is hung on the body of the passenger. When the omission is attached to the buckle, the webbing 22 is attached to the occupant's body, the occupant's body is restrained by the webbing 22, and the buckle switch 262 is turned off (OFF state). On the other hand, when the tongue is pulled out from the buckle, the buckle switch 262 is turned on (ON state).

  The other fixed contact of the buckle switch 262 is connected to a battery 264 mounted on the vehicle. On the other hand, the inner contact 252 is connected to the one end of the motor 32 described above from the outside of the cover 48 (that is, the end of the frame 246 opposite to the sliding contact portion with the inner ring terminal 242 in FIG. 1). The other end of the motor 32 is grounded.

  On the other hand, as shown in FIG. 7, a contact plate 272 formed of a conductive plate material such as copper is provided inside the switch second rotating body 72. The contact plate 272 is fixed to the bottom 232 on the inner side of the switch second rotating body 72 and penetrates into the outer ring groove 236 through the portion of the bottom 232 that constitutes the inner peripheral wall portion of the outer ring groove 236. The outer ring terminal 238 in the ring groove 236 is always in contact. In addition, a contact plate 274 formed of a conductive plate material such as copper is provided inside the switch second rotating body 72. The contact plate 274 is fixed to the bottom portion 232 inside the switch second rotating body 72 and penetrates into the inner ring groove 240 through the portion of the bottom portion 232 constituting the inner peripheral wall portion of the inner ring groove 240. The inner ring terminal 242 in the ring groove 240 is always in contact.

  A slider 280 is provided on the side opposite to the bottom 232 via the contact plates 272 and 274. The slider 280 is formed in a trapezoidal flat plate shape (or block shape) in the front view (as an example in the state shown in FIG. 8) with the longitudinal direction extending along the upper and lower bottom portions. As shown in FIG. 8, a plurality of guide pins 282 are formed on the bottom portion 232 corresponding to the slider 280. When the shape of the slider 280 is regarded as a trapezoid as described above, these guide pins 282 interfere with the upper bottom portion and the lower bottom portion, respectively, and change the moving direction (sliding direction) of the slider 280 in the switch second rotating body 72. The slider 280 is restricted in the longitudinal direction.

  As shown in FIG. 7, a slider contact 284 as a movable contact formed of a conductive plate material such as copper is integrally attached to the slider 280 on the bottom 232 side of the slider 280. The slider contact 284 has a longitudinal direction along the longitudinal direction of the slider 280. When the slider 280 in the switch second rotating body 72 is in the initial position (shown in FIG. 8), the slider contact 284 is The contact plate 272 is separated from at least one of the contact plate 272 and the contact plate 274, and is electrically disconnected from the contact plate 272 and the contact plate 274.

  On the other hand, when the slider 280 slides a certain stroke in the longitudinal direction from this initial position (as shown in FIG. 10), one end of the slider contact 284 contacts the contact plate 272 and the other end contacts the contact plate 274. The contact plate 272 and the contact plate 274 are electrically connected. In this state, the slider contact 284 represented as a movable contact in FIG. 11 is closed. Further, if the buckle switch 262 is closed and becomes conductive in this state, the motor 32 is fed by the battery 264. Then, the motor 32 is driven to rotate forward. As can be seen from FIG. 11, the present embodiment does not include a configuration for switching the current flowing through the motor 32 in the reverse direction, and therefore, the motor 32 cannot be driven in reverse.

  Further, a switch operation unit 292 as a movable contact operation member is provided inside the switch second rotating body 72. The switch operation unit 292 includes a friction spring 294. The friction spring 294 is formed by appropriately bending or bending a rod-like (linear) material having spring properties. The friction spring 294 includes an insertion portion 296 as a fulcrum portion. The insertion portion 296 is formed in a rod shape whose axial direction is substantially along the axial direction of the spool 20. Corresponding to the insertion portion 296, an insertion hole 298 is formed in the bottom portion 232 on the side opposite to the circular hole 234 through the arrangement of the slider 280 in the bottom portion 232, and the insertion portion 296 is formed around the central axis. It is inserted in the insertion hole 298 so that rotation is possible.

  An operation unit 300 is continuously formed from the other end of the insertion unit 296. The operation unit 300 is formed in a bar shape whose longitudinal direction is substantially perpendicular to the central axis of the switch second rotating body 72 and the longitudinal direction of the slider 280. In addition, the position where the operation portion 300 is formed in the friction spring 294 in a state where the insertion portion 296 is inserted into the insertion hole 298 is between the position where the insertion hole 298 is formed and the position where the circular hole 234 is formed in the bottom portion 232. The shape of the friction spring 294 is set so that A pair of pressed pins 302 and 304 are formed so as to protrude from the surface of the slider 280 opposite to the bottom 232 corresponding to the operation unit 300.

  The pressed pin 302 is formed on one side in the longitudinal direction of the slider 280 with respect to the operation unit 300, and when the operation unit 300 rotates around the insertion portion 296 toward the pressed pin 302, the operation unit 300 is moved to the pressed pin 302. To slide the slider 280 in one longitudinal direction. On the other hand, the pressed pin 304 is formed on the side opposite to the pressed pin 302 via the operation unit 300, and when the operation unit 300 rotates around the insertion portion 296 toward the pressed pin 304 side, The operation unit 300 presses the pressed pin 304 and slides the slider 280 in the other longitudinal direction.

  A bending portion 306 is formed continuously from the end of the operation portion 300 opposite to the insertion portion 296. The bending portion 306 is curved so that the center of curvature is set to the rotation center side of the switch second rotating body 72 (not necessarily the rotation center of the switch second rotating body 72) and bypasses the circular hole 234. Even if the friction spring 294 rotates around the insertion portion 296, the fitting insertion hole 226 that passes through the circular hole 234 does not interfere with the insertion portion 296. The end portion of the bending portion 306 opposite to the operation portion 300 is located on the other end side in the longitudinal direction of the slider 280 with respect to the boundary virtual line C passing through the center of the insertion hole 298 and the center of the circular hole 234. Yes.

  A sliding contact portion 308 is attached to an end portion of the bending portion 306 opposite to the operation portion 300. The sliding contact portion 308 is formed in a columnar shape (or a cylindrical shape) whose axial direction is the same as the axial direction of the switch second rotating body 72. This sliding contact portion 308 (more specifically, the mounting position of the sliding contact portion 308 on the friction spring 294) is from the center of the circular hole 234 (that is, the rotation center of the switch second rotating body 72 and the center axis of the spool 20). Is set to be longer than the distance from the center of the circular hole 234 to the insertion portion 296 and the distance from the center of the circular hole 234 to the operation portion 300.

  One end of the sliding contact portion 308 in the axial direction (the end opposite to the bottom portion 232) is in sliding contact with the bottom portion 222 of the switch first rotating body 86. Therefore, when the switch second rotating body 72 described above rotates relative to the switch first rotating body 86 in the winding direction, the friction spring 294 is inserted into the insertion portion 296 due to friction between the sliding contact portion 308 and the bottom portion 222. The operation unit 300 presses the pressed pin 302 by rotating so as to approach the pressed pin 302 around.

  On the other hand, when the switch first rotating body 86 rotates relative to the switch second rotating body 72 in the pulling direction (that is, the switch first rotating body 86 rotates relative to the switch second rotating body 72 in the pulling direction). Or when the switch second rotating body 72 rotates in the winding direction with respect to the switch first rotating body 86), the friction spring 294 is inserted into the insertion portion 296 due to friction between the sliding contact portion 308 and the bottom portion 222. The operation unit 300 presses the pressed pin 304 by rotating so as to approach the pressed pin 304 around.

  As described above, when the insertion portion 296 of the friction spring 294 is the “fulcrum”, the sliding contact portion 308 is the “force point”, and the operation portion 300 is the “action point”, the friction spring 294 has the “fulcrum” and “force point”. Since the “action point” is set between them, even if the force applied to the sliding contact portion 308 that is the “power point”, that is, the force that moves the sliding contact portion 308 is relatively small, the operation unit 300 that is the “action point”. Thus, the slider 280 can be slid by pressing the pressed pin 302 or the pressed pin 304. Moreover, since the “power point” setting position is set on the side opposite to the “action point” setting position via the circular hole 234, the distance from the “power point” to the “action point” can be set sufficiently long. Therefore, the force applied to the sliding contact portion 308 required for the operation unit 300 to press the pressed pin 302 or the pressed pin 304 and slide the slider 280 can be reduced.

(Configuration of spring unit 44)
Next, the configuration of the spring unit 44 will be described. The spring unit 44 includes a spring case 322 provided on the opposite side of the cover 48 from the case main body 46. The spring case 322 is open toward the cover 48 and is fixed to at least one of the leg plate 18, the case body 46, and the cover 48. The spring case 322 is provided so as to cover the through-hole 324 formed in the cover 48 from the side opposite to the case main body 46 of the cover 48.

  The through hole 324 is formed so as to protrude coaxially with respect to the spool 20 from the insertion portion of the torsion shaft fitted into the fitting insertion hole 226 described above, or is coaxial with the spool 20 and substantially with respect to the torsion shaft. In particular, the shaft portion 326 attached to the end portion of the torsion shaft on the leg plate 18 side so as not to be relatively rotatable passes through the inside of the spring case 322 and is rotatably supported by the spring case 322. Further, a spiral spring 328 serving as a biasing means is accommodated inside the spring case 322. The end of the spiral spring 328 on the outer side in the spiral direction is locked to the spring case 322, and the end on the inner side in the spiral direction is locked to the shaft portion 326.

  The spiral spring 328 is tightened when the shaft portion 326 rotates in the pull-out direction, and biases the shaft portion 326 in the winding direction. As described above, the shaft portion 326 is basically the same in structure as the spiral spring that has been used in the conventionally known webbing take-up device to rotate the spool in the take-up direction and wind the webbing on the spool. However, in the spiral spring 328, the increase amount of the urging force that is increased per one rotation of the shaft portion 326 in the pull-out direction is set smaller than the spiral spring that has been used in the conventional webbing take-up device ( That is, the biasing force is weaker than the spiral spring of the conventional webbing take-up device.

<Operation and Effect of First Embodiment>
Next, the operation and effect of the present embodiment will be described through the description of the operation of the relative rotation detection switch 38 and the clutch unit 36 in the withdrawal of the webbing 22 from the spool 20 and the winding of the webbing 22 onto the spool 20.

(Operation of the clutch unit 36 when the webbing 22 is attached)
When an occupant seated on a vehicle seat pulls the webbing 22 to attach the webbing 22 to the body, the spool 20 rotates in the pull-out direction while the webbing 22 is pulled out from the spool 20. When the spool 20 rotates in the pull-out direction, the switch first rotating body 86 that is connected to the spool 20 through a torsion shaft (not shown) in a substantially non-rotatable state rotates in the pull-out direction. The rotational force of the switch first rotating body 86 is transmitted to the clutch output gear 78 of the clutch output side rotating body 76 via the gear 82, the two-stage gear 80, and the two-stage gear 74, and the clutch output gear 78 is transmitted to the motor 32, which will be described later. The direction opposite to the direction of rotation by the rolling drive force (in the direction of arrow B in FIG. 2, this direction is hereinafter referred to as “reverse direction” for convenience and rotation in this direction is referred to as “reverse direction” for convenience).

  Here, in the webbing take-up device 10, the webbing 22 is taken up on the spool 20 until the spool 20 can no longer be rotated in the take-up direction. Further, the operating portion 194 of the first pawl 142 presses the pin 192 of the second pawl 178 against the urging force of the return spring 184 to rotate the second pawl 178 around the shaft 176. The engaging portion 204 of the second pawl 178 meshes with the ratchet plate 202 in the form of being sucked into the ratchet teeth of the ratchet plate 202. For this reason, when the clutch output-side rotating body 76 is reversely rotated by rotating the spool 20 in the pull-out direction, the ratchet teeth of the ratchet plate 202 press the engaging portion 204 of the second pawl 178 in the reverse direction, and the sliding contact portion 200. That is, the second clutch plate 170 is reversed around the stepped shaft 106.

  In the clutch unit 36, the sliding contact portion 200 of the friction spring 198 attached to the support plate 172 of the second clutch plate 170 is in sliding contact with the second peripheral wall portion 100 of the clutch input side rotating body 68. When 68 is reversed, the second clutch plate 170 is rotated together with the clutch input side rotating body 68 due to the friction between the inner peripheral portion of the second peripheral wall portion 100 and the sliding contact portion 200. The reverse rotation of the clutch input side rotating body 68 is transmitted to the output shaft 52 of the motor 32 through the two-stage gear 64, the two-stage gear 60, the two-stage gear 56, and the gear 54, and the output when the motor 32 is driven to rotate forward. The output shaft 52 is rotated in the direction opposite to the rotation direction of the shaft 52.

  On the other hand, in the clutch unit 36, the second clutch plate 170 is rotatably supported around the small diameter shaft portion 114 of the stepped shaft 106. However, a friction spring 126 is provided between the outer peripheral portion of the medium diameter shaft portion 112 that supports the first clutch plate 120 and the inner peripheral portion of the boss 124, and the outer peripheral portion of the medium diameter shaft portion 112 and the friction spring 126. , And the friction between the inner peripheral portion of the boss 124 and the friction spring 126, the rotation of the first clutch plate 120 around the medium diameter shaft portion 112 is suppressed. Therefore, when the second clutch plate 170 is reversely rotated as described above, the second clutch plate 170 is rotated relative to the first clutch plate 120 in the reverse rotation direction (when viewed from the second clutch plate 170, the second clutch plate 170 is rotated). Relative rotation of the first clutch plate 120 in the forward rotation direction) occurs.

  When such relative rotation occurs between the first clutch plate 120 and the second clutch plate 170, the friction is caused by the friction generated between the sliding contact portion 177 of the pawl spring 152 and the support plate 172 of the second clutch plate 170. The pawl spring 152 rotates around the insertion portion 154 and the pawl operation portion 156 approaches the vertical wall portion 162. When the pawl operating portion 156 approaching the vertical wall portion 162 comes into contact with the vertical wall portion 162 and presses the vertical wall portion 162, the first pawl 142 moves around the circular hole 146 in the direction of the arrow A in FIG. For the sake of convenience, it is referred to as the “forward rotation direction”, and the rotation in this direction is referred to as “forward rotation” for the sake of convenience), and as shown in FIG. 4, the first contact with the pin 192 of the second pawl 178 until then is performed. The operation part 194 of the pawl 142 is separated from the pin 192.

  In this way, the webbing 22 is pulled out from the spool 20 while the rotational force of the spool 20 is transmitted. Further, when the webbing 22 having a length sufficient to be attached to the occupant's body is pulled out from the spool 20, the pulling is performed. The webbing 22 is hung around the occupant's body, and the tongue provided on the webbing 22 in this state is attached to the buckle (both not shown).

  On the other hand, as described above, in the webbing take-up device 10, the shaft portion 326 is connected to the spool 20 via the torsion in a state in which the shaft portion 326 is not substantially rotatable relative to the spool 20. For this reason, when the webbing 22 is pulled out from the spool 20 and the spool 20 rotates in the pull-out direction, the shaft portion 326 rotates in the pull-out direction, and the spiral spring 328 whose inner end in the spiral direction is locked to the shaft portion 326. As a result, the energizing force that energizes the shaft portion 326 and thus the spool 20 in the winding direction in the spiral spring 328 increases.

  For this reason, when the tongue is attached to the buckle in a state where the sufficiently long webbing 22 pulled out from the spool 20 is wound around the body of the occupant and the pulling of the webbing 22 by the occupant is eliminated, the spiral spring 328 The urging force causes the shaft portion 326 and thus the spool 20 to rotate in the winding direction, thereby eliminating unnecessary slack of the webbing 22 attached to the occupant's body.

  Further, when the switch first rotating body 86 is rotated in the winding direction by rotating the spool 20 in the winding direction in this way, the rotational force of the switch first rotating body 86 is the gear 82, the two-stage gear 80, the two-stage gear. The clutch output gear 78 is transmitted to the clutch output gear 78 of the clutch output side rotator 76 via the gear 74 and is rotated in the forward rotation direction. As the clutch output gear 78 rotates forward in this way, the ratchet plate 202 integral with the clutch output gear 78 rotates forward, and the engaging portion 204 of the second pawl 178 meshing with the ratchet teeth of the ratchet plate 202 becomes the ratchet plate. Separate from the 202 ratchet teeth.

  In this state, as described above, since the operation portion 194 of the first pawl 142 is separated from the pin 192, the pin 192 of the second pawl 178 does not receive interference from the operation portion 194 of the first pawl 142. . For this reason, when the engaging portion 204 is separated from the ratchet teeth of the ratchet plate 202, the second pawl 178 is rotated in the reverse rotation direction by the biasing force of the return spring 184, and the engaging portion 204 is rotated in the radial direction of the ratchet plate 202. Rotate outward. As a result, as shown in FIG. 5, the connection capable of transmitting the rotational force between the second clutch plate 170 and the clutch output side rotating body 76 is released.

  As described above, in the webbing take-up device 10, when the occupant wears the webbing 22, the output shaft 52 of the motor 32 and the motor 32 are connected via the clutch unit 36 (mechanical connection capable of transmitting a rotational force). Therefore, the resistance caused by various frictions between the second clutch plate 170 and the output shaft 52, the rotational resistance of the output shaft 52 in the motor 32, and the like do not affect the rotation of the spool 20. For this reason, in this state, even if the urging force of the spiral spring 328 is weak, unnecessary slack of the webbing 22 can be easily eliminated. Further, since the urging force of the spiral spring 328 for easily eliminating the unnecessary slack of the webbing 22 may be weak, the occupant wearing the webbing 22 does not receive great pressure from the webbing 22.

(Operation of the relative rotation detection switch 38 when the webbing 22 is mounted)
When the webbing 22 is pulled out in this way and the switch first rotating body 86 rotates in the pulling direction together with the spool 20, the rotation of the switch first rotating body 86 is switched via the clutch unit 36 to the switch second rotating body 72. Until the switch second rotation body 72 is transmitted to the switch second rotation body 72 in the pull-out direction (the direction of arrow E in FIG. 7).

  When the switch first rotating body 86 rotates relative to the switch second rotating body 72 in the pull-out direction, the friction between the bottom portion 222 of the switch first rotating body 86 and the sliding contact portion 308 of the friction spring 294 causes a change in FIG. As shown in FIG. 4, the operation portion 300 of the friction spring 294 rotates around the insertion hole 298 so as to approach the pressed pin 304. In this state, the operation portion 300 approaches the pressed pin 304. Even if the pressed pin 304 cannot be pressed, the slider contact 284 does not connect the contact plate 272 and the contact plate 274 even if the operating unit 300 presses the pressed pin 304 and the slider 280 slides. The motor 32 is not operated.

(Operation of the relative rotation detection switch 38 when the webbing 22 is stored)
On the other hand, when the occupant removes the webbing 22 attached to the body, first, the buckle is operated to remove the tongue attached to the buckle. As a result, the buckle switch 262 becomes conductive. When the tongue is removed from the buckle in this way, the spiral spring 328 rotates the shaft portion 326 in the winding direction with its urging force. When the shaft portion 326 rotates in the winding direction, the switch first rotating body 86 that cannot substantially rotate relative to the shaft portion 326 rotates in the winding direction. In this state, since the motor 32 is not yet driven, the switch second rotating body 72 is not rotating. For this reason, in this state, relative rotation of the switch first rotating body 86 in the winding direction with respect to the switch second rotating body 72 occurs.

  Thus, when the switch first rotating body 86 rotates relative to the switch second rotating body 72 in the winding direction, the friction between the bottom portion 222 of the switch first rotating body 86 and the sliding contact portion 308 of the friction spring 294 is achieved. Thus, the operation part 300 of the friction spring 294 rotates around the insertion hole 298 so as to approach the pressed pin 302. When the operating unit 300 approaching the pressed pin 302 comes into contact with the pressed pin 302 and the operating unit 300 presses the pressed pin 302, the slider 280 moves in one longitudinal direction as shown in FIG. Slide. When the slider 280 slides in this way, the contact plate 272 and the contact plate 274 are conducted through the slider contact 284. In this state, the tongue is removed from the buckle and the buckle switch 262 is in a conducting state as described above, so that the motor 32 is energized and the motor 32 is driven to rotate forward.

  Thus, the forward rotation driving force output by the forward rotation of the motor 32 is transmitted to the switch second rotating body 72 via the gear 54, the second gear 56, the second gear 60, and the second gear 64, The switch second rotating body 72 is rotated in the winding direction. Here, the outer ring terminal 238 with which the sliding piece 248 of the outer contact 244 is slidably contacted, and the inner ring terminal 242 with which the sliding piece 254 of the inner contact 252 is slidably contacted are substantially coaxial with the switch second rotating body 72. Therefore, even if the switch second rotary body 72 rotates, the sliding contact state between the sliding piece 248 of the outer contact 244 and the outer ring terminal 238 and the sliding piece 254 of the inner contact 252 and the inner ring terminal 242 are provided. Is maintained, and the energized state of the motor 32 is maintained.

  On the other hand, as will be described later in detail, the forward driving force output from the motor 32 is input to the input gear of the clutch input side rotating body 68 via the gear 54, the second gear 56, the second gear 60, and the second gear 64. When the clutch input-side rotator 68 rotates (forward rotation) by being transmitted to the part 70, the clutch unit 36 is operated, and the torque of the clutch input-side rotator 68 is applied to the clutch output gear 78 of the clutch output-side rotator 76. It is transmitted to the switch first rotating body 86 through the gear 74, the two-stage gear 80, and the gear 82, and rotates the switch first rotating body 86 in the winding direction.

  Here, the rotational speed of the switch first rotating body 86 in the winding direction due to the normal rotation driving force of the motor 32 is equal to or higher than the rotational speed of the switch second rotating body 72 in the winding direction due to the normal rotation driving force of the motor 32. In addition, the transmission ratio of the driving force from the output shaft 52 of the motor 32 to the switch second rotating body 72 of the relative rotation detecting switch 38 and the driving from the output shaft 52 of the motor 32 to the switch first rotating body 86 of the relative rotation detecting switch 38. Force transmission ratio is set.

  Therefore, in a state where both the switch first rotating body 86 and the switch second rotating body 72 are rotated by the normal driving force of the motor 32, the rotation delay of the switch second rotating body 72 with respect to the switch first rotating body 86. The state in which the operating portion 300 presses the pressed pin 302 by the friction between the bottom portion 222 of the switch first rotating body 86 and the sliding contact portion 308 of the friction spring 294 is maintained. Thus, as described above, even if both the switch first rotating body 86 and the switch second rotating body 72 are rotated in the winding direction by the normal rotation driving force of the motor 32, the contact plate 272 via the slider contact 284 is used. And the contact state of the contact plate 274 are maintained, and the energized state of the motor 32 is maintained.

  Thus, the forward rotation driving force of the motor 32 is transmitted to the spool 20 via the switch first rotating body 86 and the torsion shaft (not shown), whereby the spool 20 is rotated in the winding direction, and the webbing 22 is attached to the spool 20. It is wound up and stored from its longitudinal base end side.

  As described above, when the spool 20 rotates in the winding direction and winds up the webbing 22, the rotation of the spool 20 in the winding direction is restricted when the "all retracted state" is reached, and as a result, the switch first rotating body. The rotation of 86 in the winding direction is restricted. Although details will be described later, even if the forward rotation driving force is further output from the motor 32 in such a state, the forward rotation driving force is transmitted from the motor 32 to the clutch input side rotating body 68 by the action of the clutch unit 36. Even if the spool 20 and the rotation of the switch first rotating body 86 in the winding direction are restricted, the switch second rotating body 72 is rotated in the winding direction by the normal rotation driving force of the motor 32. Accordingly, relative rotation of the switch second rotating body 72 in the winding direction with respect to the switch first rotating body 86 (when viewed from the switch second rotating body 72, the switch first rotating body 86 with respect to the switch second rotating body 72. Relative rotation in the pull-out direction) occurs.

  When relative rotation in the winding direction of the switch second rotating body 72 with respect to the switch first rotating body 86 occurs, friction between the bottom portion 222 of the switch first rotating body 86 and the sliding contact portion 308 of the friction spring 294 results in The operation part 300 of the friction spring 294 rotates around the insertion hole 298 so as to be separated from the pressed pin 302 and approach the pressed pin 304. When the operating unit 300 approaching the pressed pin 304 comes into contact with the pressed pin 304 and the operating unit 300 further presses the pressed pin 304, the slider 280 moves to the other longitudinal direction as shown in FIG. Slide. Thus, when the slider 280 moves by a predetermined stroke, the contact between the contact plate 272 and the contact plate 274 by the slider contact 284 is released, and the power supply to the motor 32 is cut off. As a result, the driving of the motor 32 can be stopped after the “all stored state” is reached.

  Further, before the above-described “all retracted state” is reached, the rotation of the spool 20 in the winding direction may be temporarily restricted, for example, by the occupant pulling the webbing 22 or the like. Even in such a case, the operation unit 300 of the friction spring 294 is separated from the pressed pin 302, and further, the motor until the slider 280 slides for a predetermined stroke by contacting the pressed pin 304 and pressing the pressed pin 304. The energization state to 32 is maintained. For this reason, even if the webbing 22 is inadvertently pulled, the webbing 22 can be continuously wound by eliminating the pulling of the webbing 22 if the rotation restricted state of the spool 20 is within a short time.

(Operation of the clutch unit 36 when the webbing 22 is stored)
On the other hand, in the relative rotation detection switch 38, the contact plate 272 and the contact plate 274 are brought into conduction via the slider contact 284, whereby when the forward rotation driving of the motor 32 is started, as described above, the normal rotation of the motor 32 is performed. The rolling driving force is transmitted to the input gear portion 70 of the clutch input side rotating body 68 constituting the clutch unit 36 via the gear 54, the two-stage gear 56, the two-stage gear 60, and the two-stage gear 64. Then, the clutch input side rotating body 68 is rotated forward. In the clutch unit 36, the sliding contact portion 200 of the friction spring 198 attached to the support plate 172 of the second clutch plate 170 is in sliding contact with the second peripheral wall portion 100 of the clutch input side rotating body 68. When 68 is forwardly rotated, the second clutch plate 170 is forwardly rotated integrally with the clutch input side rotating body 68 by friction between the inner peripheral portion of the second peripheral wall portion 100 and the sliding contact portion 200.

  In the state shown in FIG. 5, the first clutch plate 120 does not normally rotate even if the second clutch plate 170 normally rotates as described above. Therefore, the second clutch with respect to the first clutch plate 120 does not rotate. Relative forward rotation of the plate 170 (relative reverse rotation of the first clutch plate 120 with respect to the second clutch plate 170 when viewed from the second clutch plate 170) occurs. When the support plate 172 of the second clutch plate 170 rotates forward relative to the support plate 132 of the first clutch plate 120, the pawl spring 152 is caused by friction between the sliding contact portion 177 of the pawl spring 152 and the support plate 172. Rotates around the insertion portion 154 in the direction of arrow B in FIG.

  By rotating the pawl spring 152 in this way, as shown in FIG. 6, the pawl operating portion 156 of the pawl spring 152 approaches the vertical wall portion 160 of the first pawl 142, and further, the pawl operating portion 156 When the pawl operating portion 156 presses against the vertical wall portion 160 in contact with the vertical wall portion 160, the first pawl 142 rotates about the shaft 136 in the reverse direction (the direction of arrow B in FIG. 5). In the first pawl 142 rotated in the reverse direction, the operation unit 194 approaches the pin 192 of the second pawl 178 and abuts against the pin 192 to press the pin 192. When the pin 192 is pressed by the operation portion 194, the second pawl 178 rotates in the forward rotation direction (in the direction of arrow A in FIG. 6) around the shaft 176, and the engagement portion 204 on the tip side thereof is moved to the ratchet plate 202. Approach the outer periphery of

  As shown in FIG. 3, when the engaging portion 204 approaches the outer peripheral portion of the ratchet plate 202 and the engaging portion 204 meshes with the ratchet plate 202, the second input from the clutch input side rotating body 68 via the friction spring 198 is performed. The forward rotation transmitted to the clutch plate 170 is transmitted to the ratchet plate 202, and the clutch output side rotating body 76 rotates forward. As described above, the forward rotation of the clutch output side rotator 76 is transmitted to the switch first rotator 86 via the two-stage gear 74, the two-stage gear 80, and the gear 82, and exceeds the rotational speed of the switch second rotator 72. The switch first rotating body 86 is rotated in the winding direction at a rotational speed of 1, and the rotation of the switch first rotating body 86 is transmitted to the spool 20 via the torsion shaft (not shown). Rotate in the picking direction. In this way, the forward driving force of the motor 32 is transmitted to the spool 20 and the spool 20 rotates in the winding direction, whereby the spool 20 winds up the webbing 22 from the longitudinal base end side.

  When the spool 20 is rotated by the forward rotation driving force of the motor 32 in this way, the webbing 22 is wound up and stored up to the “all stored state”, and further after the “all stored state” state is reached. In addition, the engagement between the engaging portion 204 of the second pawl 178 and the ratchet plate 202 is maintained until the occupant wears the webbing 22.

  Further, in such an “all stored state”, as described above, the rotation of the spool 20 in the winding direction is restricted, and consequently, the rotation of the switch second rotating body 72 in the winding direction is restricted. Therefore, in this state, the clutch output-side rotator 76 is normally rotated, and consequently the normal rotation of the support plate 172 (second clutch plate 170) is restricted.

  In this state, since the forward driving force is still output from the motor 32, the clutch input side rotating body 68 rotates forward and transmits this rotational force to the support plate 172 via the sliding contact portion 200 of the friction spring 198. Then, the support plate 172 is rotated forward. The rotational force of the clutch input-side rotator 68 by the forward rotation driving force from the motor 32 causes the friction between the sliding contact portion 200 of the friction spring 198 and the inner peripheral portion of the second peripheral wall portion 100 in the second clutch plate housing portion 102. When the force is exceeded, the clutch input side rotating body 68 rotates forward with respect to the second clutch plate 170 whose rotation is restricted (that is, stopped).

  As a result, even when the rotation of the spool 20 in the winding direction is restricted, the clutch input-side rotating body 68 can be rotated forward by the normal driving force of the motor 32, and the output shaft 52 of the motor 32 The forward rotation driving force of the motor 32 can be transmitted to the switch second rotating body 72 from the two-stage gear 64 interposed between the clutch input side rotating body 68 and the switch second rotating body 72 can be rotated in the winding direction. .

  As described above, even when the rotation of the spool 20 and thus the switch first rotating body 86 in the winding direction is restricted, the switch second rotating body 72 is moved in the winding direction by the normal driving force of the motor 32. Since it can be rotated, as described above, the switch second rotating body 72 can be relatively rotated in the winding direction with respect to the switch first rotating body 86 after the “all retracted state” is reached. As described above, the conduction of the contact plate 272 and the contact plate 274 can be released and the driving of the motor 32 can be stopped.

(Effect of the webbing take-up device 10)
As described above, the webbing take-up device 10 rotates the spool 20 in the take-up direction with the normal rotation driving force output from the motor 32 when the webbing 22 is taken up and stored in the spool 20. For this reason, the urging force of the spiral spring 328 may be small. Specifically, the urging force of the spiral spring 328 may cause the clutch output side rotating body 76 to rotate forward or the tongue from the buckle when the webbing 22 is attached. It is sufficient that the switch first rotating body 86 can be rotated in the winding direction when the webbing 22 is removed from the occupant's body. Thereby, the occupant wearing the webbing 22 can reduce the feeling of pressure received from the webbing 22.

  Further, since the drive control of the motor 32 is basically performed by mechanical ON (conduction) and OFF (conduction release) in the buckle switch 262 and the relative rotation detection switch 38, an expensive control such as an ECU or a computer is performed. The motor 32 can be controlled with an inexpensive configuration without using any means.

  Further, in the webbing take-up device 10, the relative rotation detection switch 38 is turned on (conductive) by the switch first rotating body 86 relatively rotating in the winding direction with respect to the switch second rotating body 72 by the biasing force of the spiral spring 328. ), And the motor 32 is driven to rotate forward. At that time, the switch first rotating body 86 must be able to rotate relative to the switch second rotating body 72 in the winding direction. For this purpose, the rotation transmission between the switch first rotating body 86 and the switch second rotating body 72 is prevented so that the switch second rotating body 72 does not follow the rotation of the switch first rotating body 86 in the winding direction. Must be shut off.

  Here, in the webbing take-up device 10, when the occupant wears the webbing 22, the switch first rotating body 86 rotates in the winding direction by the urging force of the spiral spring 328, whereby the clutch output side rotating body 76 and the shaft are rotated. The connection between the switch rotator 176 and the switch rotator 86 and the switch second rotator 72 are interrupted. As described above, since the rotation transmission between the switch first rotating body 86 and the switch second rotating body 72 can be cut off only by the occupant normally wearing the webbing 22, the switch first rotating body 86 and the switch second rotating body can be cut off. No special operation is required to cut off the rotation transmission to / from 72.

  In addition, with such a configuration, for example, the motor 32 does not need to be driven in reverse rotation in order to release the connection between the clutch output side rotating body 76 and the shaft 176. Accordingly, the driving direction of the motor 32 in the webbing take-up device 10 is basically only forward driving, and a special configuration for switching the driving direction of the motor 32 is unnecessary. In this sense, the control system of the motor 32 is not required. The configuration can be simplified and the cost can be reduced.

  Further, in the webbing take-up device 10, the drive start and stop of the motor 32 are performed only by mechanical switch operation (ON, OFF) in the relative rotation detection switch 38. For this reason, for example, a limit switch for detecting the “all stored state” and a rotary encoder for detecting the “all stored state” based on the rotational position of the spool 20 are unnecessary. However, the configuration of the control system of the motor 32 can be simplified and the cost can be reduced.

<Configuration of Second Embodiment>
Next, a second embodiment will be described. The second embodiment is a modification of the relative rotation detection switch 38 in the first embodiment, and the other configurations are basically the same as those in the first embodiment. Therefore, detailed description thereof is omitted.

(Configuration of rotation detection switch 352)
As shown in FIG. 12, the webbing take-up device 350 according to the present embodiment includes a rotation detection switch 352 that replaces the relative rotation detection switch 38 in the first embodiment. Although detailed illustration in FIG. 12 is omitted, the rotation detection switch 352 is provided on the outer side of the leg plate 18 (on the side opposite to the leg plate 16 of the leg plate 18), similarly to the relative rotation detection switch 38 in the first embodiment. It has been.

  As shown in FIG. 12, the rotation detection switch 352 includes a magnet holder 354. The magnet holder 354 has a bottomed cylindrical shape in which the axial direction is in the same direction as the axial direction of the spool 20 and the end on the leg plate 18 side is closed by the bottom wall. The magnet holder 354 is supported by a shaft (not shown) so as to be rotatable around its own central axis.

  As shown in FIGS. 12 and 13, a pair of permanent magnets 356 are provided inside the magnet holder 354. Each of the permanent magnets 356 is formed in a plate shape that is curved so that the thickness direction is along the radial direction of the magnet holder 354 and the center axis of the magnet holder 354 is the center of curvature, and the center axis of the magnet holder 354 is The magnet holder 354 is integrally attached to the outer periphery of the magnet holder 354 so as to face each other. One of these permanent magnets 356 has an N pole on the radially outer side of the magnet holder 354 with respect to the center in the thickness direction, and an S pole on the radially inner side of the magnet holder 354 with respect to the center in the thickness direction. The other permanent magnet 356 has an S-pole on the radially outer side of the magnet holder 354 than the center in the thickness direction, and an N-pole on the radially inner side of the magnet holder 354 from the center in the thickness direction. The polarity of the permanent magnet 356 is set.

  A one-turn coil 362 is provided inside the magnet holder 354. The coil 362 includes a pair of rod-like portions 364 whose longitudinal direction is the same as the direction of the central axis of the magnet holder 354. These rod-shaped portions 364 are arranged so as to face each other via the central axis of the magnet holder 354, and the distance from the central axis of the magnet holder 354 to one rod-shaped portion 364 along the radial direction of the magnet holder 354 The distance from the central axis of the magnet holder 354 to the other rod-like portion 364 is the same distance.

  The end of one rod-like portion 364 and the end of the other rod-like portion 364 on the bottom side of the magnet holder 354 are connected to each other by a rod-like portion 366. For this reason, when the permanent magnet 356 rotates together with the magnet holder 354 around the central axis of the magnet holder 354, a DC induced current flows through the coil 362. As shown in FIG. 14, the coil 362 constitutes a part of the switch circuit 372. In the switch circuit 372, one end of the coil 362 is connected to one of the terminals of the amplifier circuit 374, and the other end of the coil 362 is connected to another one of the terminals of the amplifier circuit 374. In addition, one end of a resistor 376 is connected between one end of the coil 362 and a terminal of the amplifier circuit 374 to which one end of the coil 362 is connected, and the other end of the coil 362 and the other end of the coil 362 are connected. The other end of the resistor 376 is connected between the terminals of the amplifier circuit 374.

  In the present embodiment, the coil 362 is one turn, but the coil 362 may have a plurality of turns.

  The amplifier circuit 374 includes an operational amplifier and the like, amplifies the induced current generated in the coil 362, and outputs the amplified current from the output terminal. The output terminal of the amplifier circuit 374 is connected to the base terminal of an npn transistor 378 as a switch member. The collector terminal of the transistor 378 is connected to the terminal of the buckle switch 262 opposite to the motor 32, and the emitter terminal of the transistor 378 is grounded. In this embodiment, the terminal on the opposite side of the buckle switch 262 of the motor 32 is connected to the battery 264, and the base current Ia that flows through the base terminal of the transistor 378 when the buckle switch 262 is conductive is greater than or equal to a predetermined magnitude. Then, a drive current Id for driving the motor 32 in the forward direction flows.

  On the other hand, as shown in FIG. 12, a spur gear 392 with external teeth is formed on the outer periphery of the magnet holder 354. On the side of the gear 392, a two-stage gear 394 is provided as a rotation speed increasing means. The two-stage gear 394 has an axial direction that is the same as the central axis direction of the magnet holder 354 and is rotatably supported by a shaft (not shown). The gear 392 includes a large diameter gear portion 396. The large-diameter gear portion 396 is a spur gear with external teeth having a larger diameter than the gear 392 and a larger number of teeth than the gear 392, and meshes with the gear 392. The two-stage gear 394 includes a small-diameter gear portion 398. The small-diameter gear portion 398 has a smaller diameter than the large-diameter gear portion 396 and has a smaller number of teeth than the large-diameter gear portion 396 and is a spur gear, and is coaxially and integrally with the large-diameter gear portion 396. Is formed.

  A gear 400 is provided on the side of the two-stage gear 394. The gear 400 is a spur gear with external teeth having a larger diameter than the small diameter gear portion 398 and a larger number of teeth than the small diameter gear portion 398. The gear 400 is formed with a fitting insertion hole 402 having the same shape as the fitting insertion hole 226 formed in the switch second rotating body 86 of the relative rotation detection switch 38 in the first embodiment. In this embodiment, instead of the switch second rotating body 86 of the relative rotation detection switch 38 in the first embodiment, the insertion hole 402 of the gear 400 is inserted into the leg plate 18 side portion of the torsion shaft described above. The gear 400 is connected to the torsion shaft and thus the spool 20 in a state where the relative rotation with respect to the torsion shaft and thus the spool 20 is substantially impossible.

  Accordingly, when the rotation of the spool 20 is transmitted to the gear 392 via the torsion shaft, the gear 400, and the two-stage gear 394, the gear 392 rotates in the same direction as the spool 20 faster than the rotation speed of the spool 20.

  In this embodiment, the rotational speed increasing means is constituted by one two-stage gear 394. However, the rotational speed increasing means speeds up the rotation of the spool 20 and transmits it to the magnet holder 354 to rotate the magnet holder 354. The rotation speed increasing means may be constituted by a plurality of two-stage gears, or the rotation speed increasing means may be constituted by a gear having a different configuration from the two-stage gear.

  Here, in the rotation detection switch 352 of the webbing take-up device 350, when the rotation of the spool 20 in the take-up direction is transmitted to the gear 392 and the gear 392 rotates, the positive induced current + Ic in FIG. The amplifier circuit 374 amplifies this positive induced current Ic and outputs it as a positive base current + Ia to the transistor 378.

  When the positive base current + Ia flows through the transistor 378, the collector terminal and the emitter terminal of the transistor 378 are brought into conduction, and the driving current Id can flow. On the other hand, when the rotation of the spool 20 in the pull-out direction is transmitted to the gear 392 and the gear 392 rotates, the negative induced current −Ic in FIG. 14 flows to the switch circuit 372 including the gear 392, and the amplification circuit 374 In this case, the negative induced current −Ic is amplified. However, even if such a negative induced current is amplified and output from the amplifier circuit 374, it is naturally reverse to the positive base current + Ia. The transistor 378 does not become conductive between the collector terminal and the emitter terminal.

<Operation and Effect of Second Embodiment>
(Operation of rotation detection switch 352 when webbing 22 is mounted)
In the webbing take-up device 350, for example, when the spool 20 rotates in the pull-out direction by pulling out the webbing 22 in order for an occupant to wear the webbing 22, the rotation of the spool 20 in the pull-out direction causes the two-stage gear 394 to rotate. And transmitted to the gear 392. However, since the negative induced current −Ic flows through the coil 362 when the spool 20 rotates in the pulling direction, even if the negative induced current −Ic is amplified by the amplifier circuit 374 and output as the base current, the transistor 378 There is no conduction between the collector terminal and the emitter terminal.

  Therefore, in this state, although the continuity of the buckle switch 262 is released, the drive current does not flow through the motor 32, so the motor 32 is not rotated forward.

(Operation of the rotation detection switch 352 when the webbing 22 is stored)
On the other hand, when the occupant removes the webbing 22 attached to the body, first, the buckle is operated to remove the tongue attached to the buckle. As a result, the buckle switch 262 becomes conductive. When the tongue is removed from the buckle in this way, the spiral spring 328 rotates the shaft portion 326 in the winding direction with its urging force. When the shaft portion 326 rotates in the winding direction, the gear 400 that cannot substantially rotate relative to the shaft portion 326 rotates in the winding direction.

  The rotation of the gear 400 in the winding direction is transmitted to the gear 392 while being accelerated by the two-stage gear 394, and the gear 392 rotates in the winding direction at a speed higher than that of the gear 400 and eventually the spool 20. When the gear 392 rotates in the winding direction in this way, a positive induced current + Ic flows through the switch circuit 372 including the coil 362. When the positive induced current + Ic flows through the switch circuit 372 in this way, the positive induced current + Ic is amplified in the amplifier circuit 374 and is output from the amplifier circuit 374 as the positive base current + Ia.

  When a positive base current + Ia flows through the transistor 378 output from the amplifier circuit 374, the collector terminal and the emitter terminal of the transistor 378 are brought into conduction. As described above, since the buckle switch 262 is in a conductive state in this state, the drive current Id flows, and thereby the motor 32 is driven to rotate forward. When the motor 32 is driven to rotate in the forward direction in this way, this forward rotation driving force is transmitted to the spool 20 as in the first embodiment, and rotates the spool 20 in the winding direction.

  As described above, when the spool 20 rotates in the winding direction by the normal rotation driving force output from the motor 32, the rotation of the spool 20 in the winding direction is transmitted to the gear 392 and rotates the gear 392. The positive induced current + Ic continues to flow through the switch circuit 372 including the. As a result, the conduction state of the transistor 378 is maintained, so that the forward drive of the motor 32 is continued.

  On the other hand, the webbing 22 to the spool 20 occurs when the “full storage state” is reached, or when the occupant pulls the webbing 22 before entering the “full storage state”, or the webbing 22 is caught on the door or seat of the vehicle. Is restricted, the rotation of the spool 20 in the winding direction is restricted even if the forward driving force is output from the motor 32, and the spool 20 stops. As described above, when the rotation of the spool 20 in the winding direction is stopped, the rotation of the gear 392 is also stopped, so that the positive induced current + Ic does not flow in the switch circuit 372 including the coil 362, and therefore, the transistor 378 has a positive Base current + Ia does not flow.

  Thereby, the conduction between the collector terminal and the emitter terminal of the transistor 378 is released, and the drive current Id does not flow. As a result, the forward rotation drive of the motor 32 can be stopped when the “full storage state” is reached or when the winding of the webbing 22 around the spool 20 is restricted before the “full storage state”.

  Further, as described above, the occupant pulls the webbing 22 before the “all retracted state” is reached, or the webbing 22 is caught on the door or seat of the vehicle, so that the rotation of the spool 20 in the winding direction is restricted. In such a case, the restriction on the rotation of the spool 20 in the winding direction is eliminated, and if the spiral spring 328 rotates the spool 20 in the winding direction with its urging force, the motor 32 is driven in the normal direction again. Can be made.

  As described above, in the webbing take-up device 350, the drive control of the motor 32 is basically performed by turning on (conducting) and turning off (disconnecting) the transistor 378 in the buckle switch 262 and the rotation detection switch 352. Therefore, the motor 32 can be controlled with an inexpensive configuration without using expensive control means such as an ECU or a computer.

  As can be seen from the above description, in the present embodiment, the output shaft 52 of the motor 32, the spool 20 and the rotation detection switch 352 are switched between ON (conduction) and OFF (conduction release) of the transistor 378. No relative rotation is required. Therefore, in the present embodiment, the clutch unit 36 may not be provided.

  However, for example, in order to rotate the spool 20 and thus the magnet holder 354 only by the urging force of the spiral spring 328, the resistance to the rotation of the spool 20 is greater when the connection between the spool 20 and the output shaft 52 is removed. Less. Therefore, when the clutch unit 36 is provided and the spool 20 is rotated in the winding direction by the urging force of the spiral spring 328 before the motor 32 is driven, the connection between the spool 20 and the output shaft 52 of the motor 32 is eliminated. It is preferable to adopt the configuration.

DESCRIPTION OF SYMBOLS 10 Webbing take-up device 20 Spool 22 Webbing 32 Motor 36 Clutch unit (clutch means)
38 Relative rotation detection switch 68 Clutch input side rotating body 76 Clutch output side rotating body 142 First pawl (clutch operating member)
152 Paul spring (clutch operating member)
178 Second pawl (connection member)
196 Friction clutch (friction clutch)
262 Buckle switch (mounting release detection switch)
328 Spiral spring (biasing means)

Claims (4)

A spool that winds the webbing from the base end side in the longitudinal direction by locking the long webbing and rotating in the winding direction;
Biasing means for biasing the spool in the winding direction;
A forward driving force in a direction corresponding to the winding direction can be output from the output shaft, the webbing is released from the occupant's body, and the spool is relative to the output shaft in the winding direction. A motor that rotates forward at a predetermined drive start timing that has been rotated and that is driven and stopped at a predetermined drive stop timing in which the output shaft rotates relative to the spool in the winding direction in the normal rotation drive state;
The spool and the output shaft are interposed between the output shaft of the motor and the spool, and operate when the forward driving force is output from the motor so as to transmit the forward driving force. When the rotational force of a predetermined magnitude or more that causes the output shaft to rotate relative to the spool in the forward rotation driving direction is transmitted from the output shaft in this connected state, the output shaft relative to the spool The spool is further rotated in the winding direction after the spool is rotated in the drawing direction opposite to the winding direction in the connected state, and the spool and the output shaft are connected. Clutch means for releasing
A webbing take-up device comprising: A clutch input-side rotating body that rotates by the normal rotation driving force output from the motor;
A clutch output-side rotating body connected to the spool and capable of transmitting a rotational force to and from the spool;
The clutch input side rotator is provided in the clutch input side rotator so as to be movable in the direction connected to the clutch output side rotator and in the opposite direction, and is biased in the direction opposite to the direction connected to the clutch output side rotator. By moving in a direction to connect to the clutch output side rotating body against the force, the rotation of the clutch input side rotating body is transmitted to the clutch output side rotating body by connecting to the clutch output side rotating body, and A coupling member that transmits the rotation of the clutch output-side rotating body to the clutch input-side rotating body in a direction opposite to the rolling drive direction;
When the clutch input side rotating body rotates in the forward rotation driving direction, the clutch input side approaches the connecting member and presses the connecting member. By this pressing, the connecting member is connected to the clutch output side rotating body, and A clutch operating member that is movable in a direction away from the connecting member by rotating a clutch input-side rotating body in a direction opposite to the normal rotation driving direction;
The webbing take-up device according to claim 1, wherein the clutch means is configured to include   A predetermined portion between the output shaft and the spool is connected so as to be able to transmit rotational force by friction, and the rotational force in the forward rotation driving direction of the output shaft relative to the spool exceeds the friction. The webbing take-up device according to claim 1 or 2, wherein the clutch means includes a friction clutch that allows rotation of the output shaft relative to the spool. A wearing release detection switch that is electrically connected to the motor and that is in an electrically conductive state when the wearing state of the webbing on the occupant's body is eliminated;
It is electrically connected to the motor, and is electrically connected in conjunction with relative rotation in the winding direction of the spool with respect to the output shaft, and relative to the spool in the forward drive direction with respect to the spool. A relative rotation detection switch that releases the conduction state in conjunction with rotation;
The attachment release detection switch and the relative rotation detection switch are connected to the motor so that the motor is driven to rotate forward when both the attachment release detection switch and the relative rotation detection switch are in a conductive state. The webbing take-up device according to any one of claims 1 to 3.

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