JP2009298216A - Webbing winding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rotate a winding shaft in both a winding direction and a pulling-out direction by a driving force of a motor, and to simplify a configuration for switching a connected state of the motor and the winding shaft. <P>SOLUTION: In a webbing winding device, when a drive gear 56 is rotated by the driving force of the motor, a weight 71 mounted in the drive gear 56 moves in a radius direction of the drive gear 56 by a centrifugal force, and a pawl 66 connected to the weight 71 is moved to a connection position. Accordingly, an engagement part 66B of the pawl 66 intrudes into a rotation path of a protrusion 65 of a ratchet 62, and a relative rotation to one side around an axis line and to the other side around the axis line of the ratchet 62 with respect to the drive gear 56 is limited. Thus, the ratchet 62 rotates following the drive gear 56. The ratchet 62 is connected to the winding shaft, and the winding shaft is rotated in the winding direction or the pulling out direction with respect to the rotation direction of the drive gear 56. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a webbing take-up device that takes up and stores a webbing for restraining an occupant on a take-up shaft.

Conventionally, there is a webbing take-up device in which a take-up shaft is rotated in a webbing take-up direction by a driving force of a motor (see, for example, Patent Document 1).
JP 2001-63522 A

  By the way, the webbing take-up device as described above has been devised in which the take-up shaft is rotated in both the webbing take-up direction and the webbing take-out direction by the driving force of the motor. Some apparatuses include a clutch for switching the connection state between the motor and the winding shaft. Such a clutch has a complicated structure because it is necessary to transmit the rotational force in both forward and reverse directions of the output shaft of the motor to the take-up shaft (a so-called “bidirectional clutch”).

  In consideration of the above-described facts, the present invention can rotate the winding shaft in both the winding direction and the drawing direction by the driving force of the motor and switch the connection state between the motor and the winding shaft. An object of the present invention is to obtain a webbing take-up device that can simplify the above.

  In order to solve the above-mentioned problem, the webbing take-up device according to the first aspect of the present invention winds up an occupant-constrained webbing by being rotated in the take-up direction, and the webbing is drawn out by being pulled out. A winding shaft that is rotated in the direction of rotation, and is rotated around one axis in conjunction with the rotation of the winding shaft in the winding direction, and around the axis in conjunction with rotation of the winding shaft in the pull-out direction. A first rotating body that is rotated to the other side, a second rotating body that is coaxially and relatively rotatable with respect to the first rotating body, and is attached to the second rotating body, and is attached to the first rotating body A pawl that is movable between a connection position that restricts relative rotation of the second rotary body around one axis and the other around the axis and a release position that releases the restriction; and the second rotary body Mounted relative to one side and the other The centrifugal force acting on itself by holding the pawl in the release position by being biased to the one side and rotating the second rotating body around the axis at a speed equal to or higher than a predetermined value. When the force exceeds the urging force, the inertia member is moved to the other side to move the pawl to the connecting position, and the second rotating body is moved to one side around the axis and the other around the axis at a speed equal to or higher than the predetermined value. And a rotatable motor.

  In the webbing take-up device according to claim 1, when the motor rotates the second rotating body to one side around the axis at a speed equal to or greater than a predetermined value, the inertia member attached to the second rotating body is The pawl which is moved to the other side of the rotating body and attached to the second rotating body is moved to the connecting position by the inertia member. When the pawl is moved to the coupling position, the relative rotation of the second rotating body around the axis of the first rotating body to one side is limited by the pawl, and the first rotating body follows the second rotating body and moves around the axis. And the winding shaft is rotated in the winding direction in conjunction with the first rotating body.

  On the other hand, when the motor rotates the second rotating body around the axis at the speed equal to or higher than a predetermined value, the inertia member is moved to the other side of the second rotating body by centrifugal force, and the pawl is moved to the coupling position by the inertia member. Moved. When the pawl is moved to the coupling position, relative rotation of the second rotating body around the axis of the second rotating body to the other is restricted with respect to the first rotating body, and the first rotating body follows the second rotating body and rotates around the axis to the other. At the same time, the winding shaft is rotated in the pull-out direction in conjunction with the first rotating body.

  On the other hand, when the motor stops and the second rotating body stops, the inertia member is moved to one side of the second rotating body by the biasing force, and the pawl is moved to the release position by the inertia member. In this state, the first rotating body and the second rotating body can be rotated relative to each other, and the connection state between the winding shaft and the motor is released.

  Thus, in this webbing take-up device, the take-up shaft can be rotated in both the take-up direction and the draw-out direction by the driving force of the motor, and the motor and the take-up shaft are connected when the motor is stopped. Can be released. And since the said connection state is switched when the inertia member attached to the 2nd rotary body moves a single pawl, the structure for performing the said switching can be simplified.

  A webbing take-up device according to a second aspect of the present invention is the webbing take-up device according to the first aspect, wherein one end side of the pawl is pivotally supported by the second rotating body, and the connection position and the release position are provided. The intermediate portion is connected to the inertia member, and the other end side is related to the first rotating body while being moved to the connecting position. It is characterized by matching.

  In the webbing take-up device according to claim 2, when the inertia member is moved to the other side of the second rotating body, one end side is pivotally supported by the second rotating body, and the intermediate portion is connected to the inertia member. Is rotated from the release position to the connection position, and the other end of the pawl is engaged with the first rotating body. This restricts relative rotation of the second rotating body around the axis and the other around the axis relative to the first rotating body. As described above, since the inertia member is connected to the middle portion of the pawl that is pivotally supported by the second rotating body, the other end of the pawl can be obtained even when the relative movement amount of the inertia member with respect to the second rotating body is set small. The end side can be moved greatly. Therefore, it is possible to reduce the movement space of the inertia member while ensuring the reliability of connection / release by the movement of the pawl.

  According to a third aspect of the present invention, there is provided a webbing retractor according to the second aspect of the present invention, wherein the pawl is formed by bending a wire-like metal material.

  In the webbing take-up device according to the third aspect, since the pawl is formed by bending the wire-like metal material, the pawl can be easily manufactured and the cost of the pawl can be reduced.

  The webbing take-up device according to a fourth aspect of the present invention is the webbing take-up device according to any one of the first to third aspects, wherein the first rotating body is provided with a protrusion. The pawl moves into the rotation path of the protrusion while being moved to the coupling position, and retreats out of the rotation path while being moved to the release position.

  In the webbing take-up device according to claim 4, when the pawl attached to the second rotating body is moved to the coupling position, the pawl enters the rotation path of the protrusion provided on the first rotating body. . In this state, when the pawl is engaged with the protrusion, relative rotation of the second rotating body with respect to the first rotating body around one axis and the other around the axis is restricted. Further, when the pawl is moved to the release position, the pawl is retracted outside the rotation path of the protrusion, and relative rotation to the first rotating body around the axis of the second rotating body and to the other around the axis becomes possible. .

  In this way, by moving the pawl in and out of the rotation path of the protrusion provided on the first rotating body, relative rotation to the first rotating body around the axis of the second rotating body and to the other around the axis (both) Therefore, a bidirectional clutch can be realized with a simple configuration.

  According to a fifth aspect of the present invention, there is provided a webbing take-up device which takes up a webbing for restraining an occupant by being rotated in the take-up direction and is rotated in the take-out direction by being pulled out. And a first rotation that is rotated around one axis in conjunction with the rotation of the winding shaft in the winding direction and that is rotated around the axis in association with the rotation of the winding shaft in the pull-out direction. A body, a second rotating body coaxially and relatively rotatable with respect to the first rotating body, and attached to the second rotating body so as to be movable relative to one side and the other side. And when the centrifugal force acting on the second rotating body is rotated around the axis at a speed equal to or higher than a predetermined value and the centrifugal force acting on the second rotating body exceeds the biasing force, the second rotating body is moved to the other side. One side and an axis around the axis of the first rotating body with respect to the second rotating body An inertia member for restricting the relative rotation in the around the other, is characterized by comprising a motor and rotatable one about the axis and the axis around the other at a speed of the second rotating member or the predetermined value.

  In the webbing take-up device according to claim 5, when the motor rotates the second rotating body to one side around the axis at a speed equal to or higher than a predetermined value, the inertia member attached to the second rotating body is It is moved to the other side of the rotating body. As a result, relative rotation of the second rotating body around the axis of the first rotating body to one side around the axis is restricted by the inertia member, and the first rotating body follows the second rotating body and rotates around the axis to one side. The take-up shaft is rotated in the winding direction in conjunction with the first rotating body.

  On the other hand, when the motor rotates the second rotating body to the other around the axis at a speed equal to or higher than a predetermined value, the inertia member is moved to the other side of the second rotating body by centrifugal force. As a result, the relative rotation of the second rotating body around the axis of the second rotating body relative to the other with respect to the first rotating body is limited by the inertia member, and the first rotating body follows the second rotating body and rotates around the axis to the other side. The take-up shaft is rotated in the pull-out direction in conjunction with the first rotating body.

  On the other hand, when the motor stops and the second rotating body stops, the inertia member is moved to one side of the second rotating body by the biasing force. Thereby, relative rotation between the first rotating body and the second rotating body becomes possible, and the connection state between the winding shaft and the motor is released.

  Thus, in this webbing take-up device, the take-up shaft can be rotated in both the take-up direction and the draw-out direction by the driving force of the motor, and the motor and the take-up shaft are connected when the motor is stopped. Can be released. And since the said connection state is switched by the inertia member attached to the 2nd rotary body, the structure for performing the said switching can be simplified.

  As described above, according to the webbing take-up device according to the present invention, the take-up shaft can be rotated in both the take-up direction and the draw-out direction by the driving force of the motor, and the motor, the take-up shaft, It is possible to simplify the configuration for switching the connection state.

  FIG. 1 shows a schematic sectional view of a motor retractor 10 as a webbing take-up device according to an embodiment of the present invention as viewed from the front side. FIG. 2 is an exploded perspective view schematically showing the overall configuration of the motor retractor 10. Further, FIG. 3 is a sectional view showing the configuration of the main part of the motor retractor 10, and FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is an exploded perspective view showing the configuration of the main part of the motor retractor 10.

  As shown in FIG. 1, the motor retractor 10 includes a frame 12. The frame 12 includes a substantially plate-like back plate 14. The motor retractor 10 is fixed to the vehicle body by fixing the back plate 14 to the vehicle body by fastening means (not shown) such as a bolt. Yes. A pair of leg pieces 16 and 18 are extended in parallel from both ends of the back plate 14 in the width direction, and a spool 20 formed in a cylindrical shape by die casting or the like is rotatable between the leg pieces 16 and 18. Is arranged.

  The spool 20 is fixed with a base end portion of an occupant restraining webbing 28 formed in a long band shape, and the spool 20 is rotated around one of its axes (hereinafter, this direction is referred to as a “winding direction”). As a result, the webbing 28 is wound around the outer periphery of the spool 20 from the base end side in a layered manner. Further, if the webbing 28 is pulled from the front end side, the webbing 28 wound around the outer periphery of the spool 20 is pulled out, and accordingly, the spool 20 rotates in the direction opposite to the rotation direction when the webbing 28 is wound up. (Hereinafter, the rotation direction of the spool 20 when pulling out the webbing 28 is referred to as a “drawing direction”).

  A case 22 is fixed to the outside of the frame on the leg piece 18 side. In the case 22, a lock mechanism (not shown) and the like are accommodated. The lock mechanism normally allows the spool 20 to freely rotate in the winding direction and the pulling direction, and prevents the spool 20 from rotating in the pulling direction during sudden deceleration of the vehicle.

  Further, the spool 20 includes a connecting portion 29 that protrudes coaxially from the end on the leg piece 16 side. The connecting portion 29 protrudes outside the frame 12 through a circular hole formed in the leg piece 16 substantially coaxially. A case 32 is fixed to the outside of the frame 12 on the leg piece 16 side. The case 32 is open on the frame 12 side, and the opening is closed by a cover 34 that is screwed to the case 32. As shown in FIG. 2, the case 32 also has an opening formed on the side opposite to the frame 12, and this opening is closed by a cover 36 screwed to the case 32.

  As shown in FIG. 3, the case 32 accommodates a barrel 38 constituting the first driving force transmission means and the second driving force transmission means. The barrel 38 is formed in a cylindrical shape in which both end portions in the axial direction are closed, and flat teeth 40 are formed on the outer peripheral portion.

  As shown in FIG. 4, the barrel 38 is rotatably supported by a cylindrical support shaft 42 projecting from the side wall of the case 32, and the spool 20 penetrates a circular hole formed in the cover 34. Is connected to the connecting portion 29 coaxially and integrally, and rotates integrally with the spool 20.

  A spiral spring 44 is accommodated inside the barrel 38. The spiral spring 44 has its inner end locked to the support shaft portion 42 of the case 32 and its outer end locked to the barrel 38. The spiral spring 44 urges the spool 20 in the winding direction via the barrel 38.

  The biasing force of the spiral spring 44 (based on the winding force of the webbing 28) is set to be relatively weak enough to eliminate the slack of the webbing 28 worn by the passenger. In other words, the urging force of the spiral spring 44 is set so as to have a strength corresponding to the occupant non-compressing property when the webbing 28 is attached, and the webbing 28 pulled out from the spool 20 resists the frictional force and the like. The strength to wind up is not required.

  Further, as shown in FIG. 1, the motor retractor 10 includes a motor 48. The motor 48 is disposed below the spool 20 between the pair of leg pieces 16 and 18 of the frame 12, and is fixed to the side wall of the case 32. An output shaft 50 of the motor 48 passes through the side wall of the case 32 and protrudes into the case 32, and a spur gear output gear 52 is attached to the output shaft 50.

  In the case 32, a meshing clutch 54 constituting a first driving force transmission means is provided. As shown in FIGS. 4 to 11, the meshing clutch 54 has a drive gear 56. The drive gear 56 is rotatably supported by the case 32 as a support shaft 58 attached to the case 32 passes through the shaft center portion. Further, spur external teeth 60 are formed on the outer peripheral portion of the drive gear 56, and the external teeth 60 are engaged with the output gear 52 described above. For this reason, when the output gear 52 rotates around one axis (in the direction of arrow C) (when the output shaft 50 of the motor 48 rotates in the forward direction), the drive gear 56 rotates around one axis (in the direction of arrow E). Is rotated around the axis in the other direction (arrow D direction) (when the output shaft 50 of the motor 48 is reversed), the drive gear 56 is rotated around the axis in the other direction (arrow F direction).

  A disc-shaped ratchet 62 that is formed in a disc shape and constitutes the meshing clutch 54 is provided on one side in the axial direction of the drive gear 56 (the arrow A direction side in FIGS. 7 and 8). The ratchet 62 is rotatably supported by the case 32 by the support shaft 58 passing through the shaft center portion, and is rotatable relative to the drive gear 56. A cylindrical projection 63 formed in a columnar shape is coaxially and integrally provided on the drive gear 56 side of the ratchet 62, and a pair of projections 65 are provided on the outer periphery of the cylindrical projection 63. Is provided. These protrusions 65 are arranged on opposite sides of each other via a support shaft 58 (rotation axis of the ratchet 62). Further, the protrusion 65 and the columnar protrusion 63 are disposed inside a bottomed cylindrical boss 55 formed in the axial center of the drive gear 56.

  A pawl 66 that constitutes the meshing clutch 54 is provided on the other side in the axial direction of the drive gear 56 (the arrow B direction side in FIGS. 7 and 8). The pawl 66 is formed by bending a wire-like metal material. One end of the pawl 66 is bent in an L shape, and a shaft 66A that protrudes toward the drive gear 56 is provided at one end of the pawl 66. The shaft portion 66A is pivotally supported by a bearing hole 57 formed on the outer peripheral side of the drive gear 56. Thus, the pawl 66 is supported so as to be rotatable around the shaft portion 66A with respect to the drive gear 56, and can be rotated between the release position shown in FIG. 9 and the connection position shown in FIG. ing.

  An intermediate portion of the pawl 66 extends from the shaft portion 66 </ b> A toward the circumferential side of the drive gear 56 (the direction of the arrow E), and the other end side of the pawl 66 is the radially inner side of the drive gear 56. Is bent towards. Further, the other end side of the pawl 66 is bent toward the drive gear 56 side, and an engaging portion 66B protruding toward the drive gear 56 side is formed at the other end portion of the pawl 66. The engaging portion 66B passes through a through hole 59 formed in the boss portion of the drive gear 56 in a non-contact state, and the outer peripheral portion of the columnar protruding portion 63 inserted into the boss portion 55 of the drive gear 56. Opposite to.

  Here, as shown in FIG. 10, in a state where the pawl 66 is disposed at the coupling position, the engaging portion 66 </ b> B of the pawl 66 enters the rotation path of the protrusion 65 of the ratchet 62. In this state, when the drive gear 56 rotates relative to the ratchet 62 to one side around the axis, the engaging portion 66B of the pawl 66 comes into contact with one end portion (the end portion on the arrow F direction side) of the projection 65. The relative rotation of the drive gear 56 around the axis of the ratchet 62 in one direction is restricted.

  In this state, when the drive gear 56 rotates relative to the ratchet 62 relative to the other axis, the engaging portion 66B of the pawl 66 is connected to the other end of the projection 65 (in the direction of arrow E), as shown in FIG. The end portion of the drive gear 56 relative to the ratchet 62 is restricted from rotating relative to the other.

  Further, as shown in FIG. 9, in a state where the pawl 66 is disposed at the release position, the engaging portion 66 </ b> B of the pawl 66 is retracted out of the rotation path of the protrusion 65 of the ratchet 62. In this state, relative rotation of the drive gear 56 with respect to the ratchet 62 around one axis and the other around the axis is allowed.

  On the other side in the axial direction of the drive gear 56 (the arrow B direction side in FIGS. 7 and 8), a weight 71 as an inertia member constituting the meshing clutch 54 is provided. The weight 71 is formed of a metal material in a substantially semicircular plate shape, and a long hole 72 is formed in a substantially central portion of the weight 71. A cylindrical support shaft 53 protruding from the axial center portion of the drive gear 56 is fitted into the long hole 72.

  Further, on the outer peripheral side of the weight 71, an arc-shaped projecting portion 81 (see FIG. 8) projecting toward the drive gear 56 is provided. The arcuate protrusion 81 is inserted inside an arcuate arc groove 83 (see FIG. 7) formed on the outer peripheral side of the drive gear 56. The width dimension of the arc groove 83 (the dimension along the radial direction of the drive gear 56) is formed sufficiently larger than the width dimension of the arc-shaped protrusion 81. A guide wall 85 (see FIG. 7) is provided in the arc groove 83 along the radial direction of the drive gear 56, and the guide wall 85 is formed at the center in the circumferential direction of the arc-shaped protrusion 81. It is inserted into the notch 87. Accordingly, the weight 71 is supported so as not to rotate relative to the drive gear 56 and to be relatively movable in the radial direction.

  The weight 71 is provided with a connecting portion 73 that protrudes toward the opposite side of the center of gravity X (see FIGS. 9 to 11) through the long hole 72. A connecting groove 74 is formed on the distal end side of the connecting portion 73, and the intermediate portion of the pawl 66 described above is inserted into the connecting groove 74. As a result, the pawl 66 and the weight 71 are connected, and when the weight 71 moves relative to the drive gear 56 in the radial direction, the pawl 66 is rotated in conjunction with the relative movement. .

  Specifically, as shown in FIG. 9, when the weight 71 is moved to one side in the radial direction of the drive gear 56 (the side where the center of gravity X approaches the support shaft 58), the pawl 66 moves to the release position. Is done. As shown in FIGS. 10 and 11, when the weight 71 is moved to the other side in the radial direction of the drive gear 56 (the side where the center of gravity X is separated from the support shaft 58), the pawl 66 moves to the coupling position. Is done.

  Further, a spring contact portion 75 that protrudes toward the drive gear 56 is provided at one end of the weight 71, and the spring contact portion 75 is formed on the outer peripheral side of the drive gear 56. Has been inserted inside. The spring accommodating portion 76 is formed in a long groove shape along the moving direction of the weight 71 with respect to the drive gear 56, and a return spring 77 (torsion coil spring) is accommodated in the spring accommodating portion 76. Yes. The return spring 77 has one end abutting against the inner wall of the spring accommodating portion 76 and the other end abutting against the spring abutting portion 75 to urge the weight 71 toward one side in the radial direction of the drive gear 56. Yes. Therefore, the weight 71 is normally held on one side of the drive gear 56 in the radial direction (position shown in FIG. 9), and the pawl 66 is held at the release position by the weight 71.

  In the mesh clutch 54 having the above-described configuration, when the drive gear 56 is rotated to one side around the axis line at a speed equal to or higher than a predetermined value, the radial direction of the drive gear 56 is caused by the centrifugal force acting on the gravity center X of the weight 71. The pawl 66 is moved by the weight 71 to the connecting position. Similarly, when the drive gear 56 is rotated to the other side around the axis at a speed equal to or higher than a predetermined value, the weight 71 is moved to the other side in the radial direction of the drive gear 56 by the centrifugal force acting on the gravity center X of the drive gear 56, The pawl 66 is moved to the connecting position by the weight 71.

  On the other hand, on one side in the axial direction of the ratchet 62 (the arrow A direction side in FIGS. 7 and 8), a drum 80 that is formed in a bottomed cylindrical shape and constitutes the slip mechanism 78 is provided. The drum 80 is rotatably supported by the case 32 by the support shaft 58 passing through the shaft center portion, and is rotatable relative to the ratchet 62. Further, spur external teeth 82 are formed on the outer peripheral portion of the drum 80. As shown in FIG. 5, the external teeth 82 mesh with the external teeth 40 of the barrel 38, and when the drum 80 rotates around one of its axes (in the direction of arrow E), the barrel 38 rotates in the winding direction (indicated by the arrow). When the drum 80 rotates in the G direction) and the drum 80 rotates in the other direction (arrow F direction), the barrel 38 rotates in the drawing direction (arrow H direction).

  Inside the drum 80, a first friction spring 84 that is formed in a spiral shape by a wire-like spring material and constitutes a slip mechanism 78 is provided. The outer diameter of the first friction spring 84 is slightly larger than the inner diameter of the drum 80, and its own outer peripheral portion is brought into close contact with the inner peripheral surface of the drum 80 by its own elastic force. For this reason, the first friction spring 84 is connected (held) to the drum 80 by a frictional force, and basically rotates integrally with the drum 80.

  Further, a spring locking portion 79 formed in a cylindrical shape is coaxially and integrally provided on the drum 80 side of the ratchet 62, and one end portion of the first friction spring 84 in the winding direction is provided with this spring locking portion. Locked to the portion 79. For this reason, the ratchet 62 and the drum 80 are connected via the first friction spring 84, and when the ratchet 62 rotates, the first friction spring 84 and the drum 80 rotate. However, as described above, the first friction spring 84 is configured to be held by the frictional force with respect to the drum 80, so that a relative rotational force exceeding the frictional force acts between the ratchet 62 and the drum 80. Then, when the first friction spring 84 slips with respect to the drum 80, the ratchet 62, the first friction spring 84, and the drum 80 are relatively idle.

  On the other hand, as shown in FIGS. 5, 12, and 13, the motor retractor 10 includes an overload mechanism 86 that constitutes a second driving force transmission unit. The overload mechanism 86 has an intermediate gear 88 formed in a bottomed cylindrical shape. The intermediate gear 88 is rotatably supported by the case 32 as a support shaft 90 (see FIG. 12) attached to the case 32 passes through the shaft center portion. Further, spur external teeth 92 are formed on the outer peripheral portion of the intermediate gear 88, and the external teeth 92 are meshed with the output gear 52 described above. For this reason, when the output gear 52 rotates around one axis (in the direction of arrow C) (when the output shaft 50 of the motor 48 rotates forward), the intermediate gear 88 rotates around one axis (in the direction of arrow I). Is rotated around the axis in the other direction (arrow D direction) (when the output shaft 50 of the motor 48 is reversed), the intermediate gear 88 is rotated around the axis in the other direction (arrow J direction).

  An adapter 94 constituting an overload mechanism 86 is provided on one side in the axial direction of the intermediate gear 88 (the arrow A direction side in FIG. 5). The adapter 94 has a flange portion 96 that is formed in a disk shape and is rotatably fitted to the opening of the intermediate gear 88. Further, a gear portion 98 formed in a cylindrical shape is coaxially formed on one side in the axial direction of the flange portion 96 (the arrow B direction side in FIG. 5). Flat teeth 100 are formed on the outer periphery of the gear portion 98. Further, on the other axial side of the flange portion 96 (the arrow A direction side in FIG. 5), a holding portion 102 that is formed in a cylindrical shape and is accommodated inside the intermediate gear 88 is coaxially projected.

  An annular gap is formed between the outer peripheral surface of the holding portion 102 and the inner peripheral surface of the intermediate gear 88. The gap is formed in a spiral shape by a wire-like spring material. The 2nd friction spring 104 which comprises is accommodated. The second friction spring 104 has an inner diameter that is slightly smaller than the outer diameter of the holding portion 102, and its own inner peripheral portion is brought into close contact with the outer peripheral surface of the holding portion 102 by its own elastic force. The holding part 102 is connected (held) by frictional force. For this reason, the second friction spring 104 basically rotates integrally with the intermediate gear 88.

  Further, both ends of the second friction spring 104 in the winding direction interfere with the intermediate gear 88, and relative rotation with respect to the intermediate gear 88 is restricted. For this reason, the intermediate gear 88 and the adapter 94 are connected via the second friction spring 104, and when the intermediate gear 88 rotates, the second friction spring 104 and the adapter 94 rotate. However, since the second friction spring 104 is held by the frictional force with respect to the adapter 94 as described above, a relative rotational force exceeding the frictional force is exerted between the intermediate gear 88 and the adapter 94. When it acts, the second friction spring 104 slips with respect to the adapter 94, so that the intermediate gear 88, the second friction spring 104, and the adapter 94 are idled relatively.

  Further, the motor retractor 10 includes a centrifugal clutch 106 that constitutes a second driving force transmission means. The centrifugal clutch 106 includes a rotor 108 formed in a bottomed cylindrical shape. The rotor 108 is rotatably supported by the case 32 as the support shaft 110 attached to the case 32 passes through the axial center portion of the bottom wall. In addition, a cover 112 formed in a disk shape from a metal plate material is attached to the opening of the rotor 108 with a screw. Further, spur external teeth 114 are formed on the outer peripheral portion of the rotor 108, and the external teeth 114 mesh with the external teeth 100 of the gear portion 98 of the adapter 94 described above. For this reason, when the adapter 94 is rotated around one axis (in the direction of arrow I), the rotor 108 is rotated around one axis (in the direction of arrow K), and when the adapter 94 is rotated around the axis in the other direction (in the direction of arrow J). Rotates around the axis in the other direction (arrow L direction).

  A gear 116 that is formed in a cylindrical shape and constitutes the centrifugal clutch 106 is provided on one side in the axial direction of the rotor 108 (side in the direction of arrow A in FIG. 5). The gear 116 is rotatably supported by the case 32 when the support shaft 110 passes through the shaft center portion, and can rotate relative to the rotor 108. A spur tooth 118 is formed on the outer peripheral portion of the gear 116 in one axial direction (arrow A direction side in FIG. 5), and this external tooth 118 meshes with the external tooth 40 of the barrel 38 described above. Has been. For this reason, when the gear 116 rotates around one axis (in the direction of the arrow K), the barrel 38 rotates in the pull-out direction (arrow H direction), and when the gear 116 rotates around the other axis (in the arrow L direction) 38 rotates in the winding direction (arrow G direction).

  Further, ratchet teeth 120 are formed on the outer peripheral portion of the other end side in the axial direction of the gear 116 (side in the arrow B direction in FIG. 5). The ratchet teeth 120 are arranged inside the rotor 108 via a circular hole 122 formed in the axial center portion of the cover 112.

  Inside the rotor 108, a pair of weights 124 that are formed in a substantially semicircular plate shape by a metal material such as iron and constitute the centrifugal clutch 106 are arranged. The pair of weights 124 are formed to have the same weight, and are arranged on opposite sides (180 ° opposite sides) along the circumferential direction of the rotor 108. A circular bearing hole 126 is formed at one circumferential end of each of the pair of weights 124, and a cylindrical shaft portion 128 protruding from the bottom wall of the rotor 108 is rotated in these bearing holes 126. Fits freely. Accordingly, the pair of weights 124 are supported by the rotor 108 so as to be rotatable about the shaft portion 126 in the radial direction of the rotor 108.

  The pair of weights 124 are urged radially inward of the rotor 108 by a pair of torsion coil springs 130 attached to the bottom wall of the rotor 108, respectively, and are usually held radially inward of the rotor 108. Yes. Further, the pair of weights 124 are formed with meshing protrusions 132 at positions facing the ratchet teeth 118 of the gear 116 described above. These engagement protrusions 132 are separated from the ratchet teeth 120 in a state where the pair of weights 124 are held radially inward of the rotor 108.

  Between the pair of weights 124 and the cover 112, a sheet 134 formed in a ring shape from a resin material plate is disposed, and the pair of weights 124 is prevented from directly rubbing against the cover 112. .

  Here, when the rotor 108 rotates around the axis thereof in the other direction (arrow L direction), the pair of weights 124 supported by the rotor 108 follows the rotor 108 and rotates around the axis line of the rotor 108. At this time, centrifugal force acts on the pair of weights 124. Therefore, when the centrifugal force acting on the pair of weights 124 exceeds a predetermined value (when the rotational speed of the rotor 108 exceeds a predetermined value), the pair of weights 124 resists the biasing force of the pair of torsion coil springs 130. The rotor 108 is rotated outward in the radial direction. As described above, when the pair of weights 124 rotate outward in the radial direction of the rotor 108, the pair of meshing protrusions 132 provided on the pair of weights 124 mesh with the ratchet teeth 120 of the gear 116. . In a state where the pair of meshing protrusions 132 mesh with the ratchet teeth 120, the rotor 108 and the gear 116 are integrally connected via the pair of weights 124, and the rotor 108, the pair of weights 124, and the gear 116 are integrally formed. It is configured to rotate.

  Further, when the centrifugal force acting on the pair of weights 124 is less than a predetermined value (when the rotational speed of the rotor 108 is less than a predetermined value), the pair of weights 124 is moved by the biasing force of the pair of torsion coil springs 130. It is rotated inward in the radial direction, and the meshing state between the pair of meshing protrusions 132 and the ratchet teeth 120 of the gear 116 is released. In this state, the rotor 108 and the gear 116 are relatively idle.

  Here, in the motor retractor 10, the reduction ratio by the output gear 52, the external teeth 60 of the drive gear 56, the external teeth 82 of the drum 80, and the external teeth 40 (first driving force transmission means) of the barrel 38 is determined by the output gear. 52, the external teeth 92 of the intermediate gear 88, the external teeth 100 of the gear portion 98 of the adapter 94, the external teeth 114 of the rotor 108, the external teeth 118 of the gear 116, and the external teeth 40 of the barrel 38 (second driving force transmission means). It is set sufficiently lower than the total reduction ratio.

  On the other hand, as shown in FIG. 1, the motor retractor 10 is configured such that power supply to the motor 48 is controlled by the control device 138. The control device 138 includes a driver 140 and an ECU 142. The motor 48 is electrically connected to a battery mounted on the vehicle via a driver 140, and current from the battery is supplied via the driver 140. The driver 140 is connected to the ECU 142, and the ECU 142 is configured to control the presence / absence of power supply to the motor 48 via the driver 140, the direction and magnitude of the supply current.

  The ECU 142 is connected to a buckle switch 146 that outputs a signal according to whether or not the occupant is wearing the webbing 28 and a front monitoring device 148 that outputs a signal according to the distance between the vehicle and an obstacle ahead of the vehicle. .

  The buckle switch 146 outputs an ON signal to the ECU 142 when the tongue plate provided on the webbing 28 is connected to the buckle device (both not shown), and the connection state of the tongue plate to the buckle device is released. An OFF signal is output to the ECU 142 when the vehicle is on. That is, the buckle switch 146 outputs either the ON signal or the OFF signal to the ECU 142 in accordance with whether or not the tongue plate and the buckle device corresponding to whether or not the webbing 28 is attached by the occupant.

  The front monitoring device 148 includes an infrared sensor 150 provided near the front end of the vehicle. The infrared sensor 150 emits infrared rays in front of the vehicle, and is referred to as an “obstacle” for convenience, including other vehicles and obstacles that are running or stopped in front of the vehicle (hereinafter, including other vehicles that are running or stopped). ) To receive the reflected infrared light.

  Further, the forward monitoring device 148 includes a calculation unit 152. The calculation unit 152 calculates the distance to the obstacle based on the time required to return to the infrared sensor 150 after being reflected by the obstacle after the infrared ray is emitted from the infrared sensor 150. In addition, the calculation unit 152 outputs an obstacle detection signal Os to the ECU 142 based on the calculation result. The obstacle detection signal Os is at a low level if the distance to the obstacle is equal to or greater than a predetermined value, and is at a high level if the distance to the obstacle is less than the predetermined value.

  Here, in the motor retractor 10, when the signal input from the buckle switch 146 changes from the ON signal to the OFF signal, the ECU 142 outputs a control signal for starting power supply to the motor 48 to the driver 140. The driver 140 to which the control signal is input supplies the motor 48 with the current F1 having the current value I1 from the battery. In this case, the output shaft 50 (output gear 52) of the motor 48 rotates in the positive direction (arrow C direction) at the first speed, and the drive gear 56 rotates around the axis line at one speed (arrow E direction) at a speed greater than a predetermined value. To be rotated.

  Further, when the occupant tries to wear the webbing 28 (for example, when the webbing 28 is fully stored in the motor retractor 10), the take-up amount sensor (not shown) rotates the spool 20 in the pull-out direction. When it is detected), a control signal for starting power supply to the motor 48 is output to the driver 140. The driver 140 to which the control signal is input supplies the motor 48 with a current R1 having a current value I1 from the battery. In this case, the current value I1 of the current R1 is set to the same magnitude as the current value I1 of the current F1, and the direction of the current R1 is set to be opposite to the direction of the current F1. Therefore, in this case, the output shaft 50 (output gear 52) of the motor 48 rotates in the reverse direction (arrow D direction) at the first speed, and the drive gear 56 rotates around the axis line at the speed equal to or higher than a predetermined value (arrow F). Direction).

  Further, when the obstacle detection signal Os input from the calculation unit 152 changes from the Low level to the High level, the ECU 142 outputs an operation signal for starting power supply to the motor 48 to the driver 140. The driver 140 to which the operation signal is input supplies the motor 48 with a current R2 having a current value I2 from the battery. In this case, the current value I2 of the current R2 is set to be larger than the current value I1 of the currents F1 and R1, and the direction of the current R2 is set to be opposite to the direction of the current F1. Therefore, in this case, the output shaft 50 (output gear 52) of the motor 48 rotates in the reverse direction (arrow D direction) at a second speed faster than the first speed.

  Next, the operation of this embodiment will be described.

  In the motor retractor 10 configured as described above, when the occupant pulls a tongue plate (not shown) with the webbing 28 wound around the spool 20 in a layered state, the spool 20 moves in the pull-out direction against the urging force of the spiral spring 44. The webbing 28 is pulled out while being rotated. When a winding amount sensor or the like (not shown) detects rotation of the spool 20 in the pull-out direction, the ECU 142 and the driver 140 rotate the output shaft 50 (output gear 52) of the motor 48 in the reverse direction (the other around the axis line). , In the direction of arrow D in FIG.

  When the output gear 52 rotates around the axis at the first speed in the other direction (arrow D direction), the intermediate gear 88 of the overload mechanism 86 in which the external gear 92 meshes with the output gear 52 moves around the axis in the other direction (arrow J direction). Rotate.

  The rotation of the intermediate gear 88 is transmitted to the adapter 94 via the second friction spring 104, and the adapter 94 rotates around the axis in the other direction (arrow J direction). For this reason, the rotor 108 of the centrifugal clutch 106 in which the external teeth 114 are engaged with the external teeth 100 of the gear portion 98 of the adapter 94 is rotated around the axis in the other direction (arrow L direction), and a pair of weights 124 supported by the rotor 110. Centrifugal force acts on In this case, the centrifugal force acting on the pair of weights 124 does not increase to the extent that the pair of weights 124 is rotated radially outward of the rotor 108 against the biasing force of the pair of torsion coil springs 130. The pair of weights 124 are held radially inward of the rotor 108 by the urging force of the pair of torsion coil springs 130. In this state, the pair of meshing protrusions 132 are separated from the ratchet teeth 120 of the gear 116, and the rotor 108 moves with respect to the gear 116 together with the pair of weights 124, the pair of torsion coil springs 130, the seat 134, and the cover 112. Relatively idle.

  On the other hand, as described above, when the output gear 52 rotates around the axis at the first speed in the other direction (arrow D direction), the drive gear 56 of the mesh clutch 54 in which the external gear 60 is meshed with the output gear 52 is greater than or equal to a predetermined value. Rotate around the axis to the other (in the direction of arrow F in FIG. 5) When the drive gear 56 rotates around the axis at a speed equal to or higher than a predetermined value, the centrifugal force acting on the center of gravity X of the weight 71 becomes larger than the urging force of the return spring 77, and the weight 71 becomes the urging force of the return spring 77. Accordingly, the drive gear 56 is moved to the other side in the radial direction. For this reason, the pawl 66 whose intermediate portion is connected to the connecting portion 73 of the weight 71 is rotated from the release position to the connecting position, and the engaging portion 66B of the pawl 66 is in the rotation path of the protrusion 65 of the ratchet 62. invade. In this state, when the drive gear 56 rotates around the axis to the other side, the engaging portion 66B of the pawl 66 contacts the protrusion 65 of the ratchet 62, and the rotational force of the drive gear 56 is transmitted to the ratchet 62 via the pawl 66. . As a result, the ratchet 62 is rotated around the axis in the other direction (in the direction of arrow F in FIG. 5).

  The rotation of the ratchet 62 around the axis is transmitted to the drum 80 via the first friction spring 84, the drum 80 is rotated around the axis to the other, and the barrel 38 is pulled out (in the direction of arrow H in FIG. 5). And eventually the spool 20 is rotated in the pull-out direction. This assists the occupant withdrawing the webbing 28, so that the occupant can pull out the webbing 28 with a light force (so-called “drawing assist mechanism”).

  When the occupant engages the tongue plate provided on the webbing 28 with the buckle device, the webbing 28 is attached to the occupant's body. In this state, the buckle switch 146 outputs an ON signal to the ECU 142, and the ECU 142 and the driver 140 stop the output shaft 50 of the motor 48. Thus, when the drive gear 56 is stopped, the weight 71 is moved to one side in the radial direction of the drive gear 56 by the urging force of the return spring 77 (the state shown in FIG. 9). For this reason, the pawl 66 having the intermediate portion connected to the connecting portion 73 of the weight 71 is rotated from the connecting position to the release position, and the engaging portion 66B of the pawl 66 moves out of the rotation path of the protrusion 65 of the ratchet 62. evacuate. As a result, the connection between the drive gear 56 and the ratchet 62 via the pawl 66 is released, and the connection between the spool 20 and the output shaft 50 of the motor 48 by the meshing clutch 54 is released. Therefore, the spool 20 rotates in the winding direction with a relatively weak rotational force corresponding to the urging force of the spiral spring 44, and the slack of the webbing 28 in the mounted state is removed.

  On the other hand, when the occupant stops the vehicle and removes the tongue plate from the buckle device, the spool 20 is rotated in the winding direction by the urging force of the spiral spring 44. However, since the biasing force of the spiral spring 44 is set to be relatively weak, the spool 20 rotates in the winding direction with a relatively weak rotational force corresponding to the biasing force of the spiral spring 44.

  At this time, the buckle switch 146 outputs an OFF signal to the ECU 142, and the ECU 142 and the driver 140 move the output shaft 50 (output gear 52) of the motor 48 in the positive direction (one around the axis, in the direction of arrow C) at the first speed. Rotate. When the output gear 52 rotates around one axis (in the direction of arrow C), the intermediate gear 88 of the overload mechanism 86 in which the external gear 92 meshes with the output gear 52 rotates around one axis (in the direction of arrow I).

  The rotation of the intermediate gear 88 is transmitted to the adapter 94 via the second friction spring 104, and the adapter 94 rotates around one axis (in the direction of arrow I). Therefore, the rotor 108 of the centrifugal clutch 106 in which the external teeth 114 are meshed with the external teeth 100 of the gear portion 98 of the adapter 94 is rotated around one axis (in the direction of the arrow K), and a pair of weights 124 supported by the rotor 110. Centrifugal force acts on In this case, the centrifugal force acting on the pair of weights 124 does not increase to the extent that the pair of weights 124 is rotated radially outward of the rotor 108 against the biasing force of the pair of torsion coil springs 130. The pair of weights 124 are held radially inward of the rotor 108 by the urging force of the pair of torsion coil springs 130. In this state, the pair of meshing protrusions 132 are separated from the ratchet teeth 120 of the gear 116, and the rotor 108 moves with respect to the gear 116 together with the pair of weights 124, the pair of torsion coil springs 130, the seat 134, and the cover 112. Relatively idle.

On the other hand, as described above, when the output gear 52 rotates around the axis at one speed (in the direction of arrow C), the drive gear 56 of the mesh clutch 54 in which the external gear 60 is meshed with the output gear 52 is greater than or equal to a predetermined value. Rotate around the axis at one speed (in the direction of arrow E).
When the drive gear 56 rotates to one side around the axis at a speed equal to or higher than a predetermined value, the centrifugal force acting on the center of gravity X of the weight 71 becomes larger than the biasing force of the return spring 77, and the weight 71 becomes the biasing force of the return spring 77. Accordingly, the drive gear 56 is moved to the other side in the radial direction. For this reason, the pawl 66 whose intermediate portion is connected to the connecting portion 73 of the weight 71 is rotated from the release position to the connecting position, and the engaging portion 66B of the pawl 66 is in the rotation path of the protrusion 65 of the ratchet 62. invade. When the drive gear 56 rotates to one side around the axis line in this state, the engaging portion 66B of the pawl 66 contacts the protrusion 65 of the ratchet 62, and the rotational force of the drive gear 56 is transmitted to the ratchet 62 via the pawl 66. . As a result, the ratchet 62 is rotated around one axis (in the direction of arrow E in FIG. 5).

  The rotation of the ratchet 62 about one axis is transmitted to the drum 80 via the first friction spring 84, the drum 80 is rotated about one axis, and the barrel 38 is wound in the winding direction (the direction of arrow G in FIG. 5). ) And the spool 20 is rotated in the winding direction. As a result, the webbing 28 is wound and stored on the spool 20 (so-called “winding assist mechanism”).

  In this case, the reduction ratio of the first driving force transmission means (the output gear 52, the external teeth 60 of the drive gear 56, the external teeth 82 of the drum 80, and the external teeth 40 of the barrel 38) is the second driving force transmission means ( Compared with the reduction ratio of the output gear 52, the external teeth 92 of the intermediate gear 88, the external teeth 100 of the gear portion 98 of the adapter 94, the external teeth 114 of the rotor 108, the external teeth 118 of the gear 116, and the external teeth 40 of the barrel 38. Since the spool 20 is set sufficiently low and the spool 20 is rotated with a low torque, the webbing 28 can be safely wound around and stored in the spool 20.

  Further, when a torque greater than the first set value is applied to the spool 20 in a state where the winding of the webbing 28 to the spool 20 is assisted through the first driving force transmission means (for example, foreign matter is applied to the webbing 28). In the case of being caught), a torque of a predetermined value or more acts on the drum 80 of the slip mechanism 78 via the spool 20 and the barrel 38. In this case, the first friction spring 84 held by the frictional force on the drum 80 idles (slips) relative to the drum 80, thereby allowing the ratchet 62 to rotate relative to the drum 80. As a result, the webbing 28 can be prevented from being forcibly wound around the spool 20 while interfering with foreign matter, and the components after the ratchet 62 (forward rotation pawl 66, drive gear 56, output gear 52, etc., output shaft 50, etc.) In this case, it is possible to prevent an excessive torque from acting on the structure), and it is possible to prevent damage to the respective parts and burning of the motor 48.

  When the webbing 28 is wound up to the end by the spool 20, the output shaft 50 (output gear 52) of the motor 48 is stopped by the ECU 142 and the driver 140, and the drive gear 56 is stopped. When the drive gear 56 stops, the weight 71 is returned to one side in the radial direction of the drive gear 56 by the urging force of the return spring 77 (the state shown in FIG. 9). For this reason, the pawl 66 having the intermediate portion connected to the connecting portion 73 of the weight 71 is rotated from the connecting position to the release position, and the engaging portion 66B of the pawl 66 moves out of the rotation path of the protrusion 65 of the ratchet 62. evacuate. As a result, the connection between the drive gear 56 and the ratchet 62 via the pawl 66 is released, and the connection between the spool 20 and the output shaft 50 of the motor 48 by the meshing clutch 54 is released. Thereby, the webbing 28 wound around the spool 20 can be pulled out again.

  On the other hand, in the running state of the vehicle, the calculation unit 152 calculates the distance to the obstacle ahead of the vehicle based on the detection result of the infrared sensor 150 of the front monitoring device 148. For example, when there is no obstacle ahead of the vehicle, or there is an obstacle but the distance from the obstacle to the vehicle is equal to or greater than a predetermined value, a low level signal is output from the calculation unit 152. On the other hand, when the distance from the vehicle to the obstacle ahead is less than a predetermined value, a high level signal is output from the calculation unit 152.

  When a high level signal is input from the calculation unit 152 to the ECU 142, the ECU 142 outputs a predetermined operation signal to the driver 140. The driver 140 to which the operation signal in this state is input starts supplying power to the motor 48 and rotates the output shaft 50 (output gear 52) in the reverse direction (the other around the axis, in the direction of arrow D) at the second speed. Let When the output gear 52 rotates around the axis to the other at the second speed, the intermediate gear 88 of the overload mechanism 86 with the external gear 92 meshed with the output gear 52 rotates around the axis in the other direction (arrow J direction).

  The rotation of the intermediate gear 88 is transmitted to the adapter 94 via the second friction spring 104, and the adapter 94 rotates around the axis in the other direction (arrow J direction). For this reason, the rotor 108 of the centrifugal clutch 106 in which the external teeth 114 are engaged with the external teeth 100 of the gear portion 98 of the adapter 94 is rotated around the axis in the other direction (arrow L direction), and a pair of weights 124 supported by the rotor 110. A centrifugal force of a predetermined value or more acts on. For this reason, the pair of weights 124 is rotated outward in the radial direction of the rotor 108 against the biasing force of the pair of torsion coil springs 130, and the meshing protrusions 132 provided on the pair of weights 124 Engage with ratchet teeth 120. Thereby, the rotation of the rotor 108 is transmitted to the gear 116 through the pair of weights 124, and the gear 116 rotates around the axis in the other direction (arrow L direction).

  For this reason, the spool 20 in which the external teeth 118 of the gear 116 are engaged with the external teeth 40 is rotated in the winding direction (arrow G direction). The rotation of the spool 20 in the winding direction causes the webbing 28 to be wound around the spool 20, whereby loosening of the webbing 28, so-called “slack” is eliminated, and the restraining force of the webbing 28 on the passenger body is improved ( So-called “pretensioner mechanism”).

  In addition, in this case, the rotation of the output shaft 50 of the motor 48 is more than the first driving force transmission means (the output gear 52, the external teeth 60 of the drive gear 56, the external teeth 82 of the drum 80, and the external teeth 40 of the barrel 38). Second drive force transmission means having a high reduction ratio (output gear 52, external teeth 92 of intermediate gear 88, external teeth 100 of gear section 98 of adapter 94, external teeth 114 of rotor 108, external teeth 118 of gear 116, barrel 38 The outer teeth 40) are transmitted to the spool 20, so that the spool 20 is rotated in the winding direction with high torque. Therefore, for example, when the webbing 28 is wound around the spool 20, even if the vehicle suddenly decelerates (rapid braking), and the occupant tries to move forward, the webbing 28 is resisted against the inertial force of the occupant. It can be forcibly wound up.

  Further, when the webbing 28 is wound around the spool 20 via the second driving force transmission means, when a torque greater than the second set value is applied to the spool 20 (for example, so-called “slack” is eliminated, When the occupant's body becomes injured and the webbing 28 can no longer be wound up), the second friction spring 104 held by the frictional force against the holding portion 102 of the adapter 94 is moved to the adapter 94. As a result, the transmission of rotation between the adapter 94 and the intermediate gear 88 (output gear 52) is disconnected, and both of them idle relatively. Accordingly, the spool 20 connected to the adapter 94 via the rotor 108, the pair of weights 124, and the gear 116 can be prevented from being rotated in the winding direction by a driving force of the motor 48 with an excessive force. It can prevent that 28 tightens a passenger | crew's body by force more than necessary.

  As described above, in the motor retractor 10 according to the present embodiment, the drawer assist mechanism, the winding assist mechanism, and the pretensioner mechanism can be established by the single motor 48, and the motor 48 is stopped when the motor 48 is stopped. The connection state between 48 and the spool 20 can be released. In addition, since the meshing clutch 54 for switching the connection state between the motor 48 and the spool 20 establishes a bidirectional clutch by a single pawl 66, the meshing clutch 54 has a very simple configuration. Yes. Therefore, the driving force transmission mechanism including the mesh clutch 54 can be reduced in size and cost.

  In the meshing clutch 54, one end side (shaft portion 66 </ b> A) of the pawl 66 is pivotally supported by the drive gear 56, and an intermediate portion of the pawl 66 is coupled to the weight 71, so that the weight 71 is connected to the drive gear 56. As a result of the relative movement in the radial direction, the other end side (engagement portion 66B) of the pawl 66 is moved. For this reason, even when the relative movement amount of the weight 71 with respect to the drive gear 56 is set small, the engaging portion 66B of the pawl 66 can be moved greatly. Therefore, it is possible to reduce the moving space of the weight 71 while ensuring the connection / release certainty by the movement of the pawl 66, and it is possible to achieve both the performance of the clutch and the miniaturization.

  Further, in the meshing clutch 54, the pawl 66 is formed by bending a wire-like metal material. Therefore, the pawl 66 can be easily manufactured, and the cost of the pawl 66 can be reduced.

  Further, in the mesh clutch 54, when the pawl 66 is moved to the coupling position, the engaging portion 66B of the pawl 66 enters the rotation path of the protrusion 65 of the ratchet 62, so that the ratchet with respect to the gear wheel 56 is obtained. The rotation to one side around the axis 62 and the other around the axis (bidirectional rotation) is limited. Therefore, a bidirectional clutch can be realized with a simple configuration.

  In the above-described embodiment, the pair of protrusions 65 is provided on the outer peripheral portion of the columnar protrusion 63 of the ratchet 62. However, the present invention is not limited to this, and the number and shape of the protrusions can be changed as appropriate. can do.

  In the above embodiment, the pawl 66 is formed by bending a wire-like metal material. However, the present invention is not limited to this, and the material and shape of the pawl can be appropriately changed. .

In the above embodiment, the pawl 66 is rotatably attached to the drive gear 56 (second rotating body), and the intermediate portion of the pawl 66 is connected to the weight 71 (inertial member). The present invention is not limited to this, and the attachment structure of the pawl to the second rotating body and the connection structure of the pawl to the inertia member can be appropriately changed. Further, in the above embodiment, the meshing clutch 54 is provided with the pawl 66. However, the present invention is not limited to this, and the pawl 66 can be omitted. That is, for example, a protruding portion that protrudes toward the drive gear 56 may be formed in the connecting portion 73 of the weight 71, and this protruding portion may be engaged with the protruding portion 65 of the ratchet 62. In this case, the configuration of the meshing clutch 54 can be further simplified.

  In the above embodiment, the weight 71 (inertial member) is attached to the drive gear 56 (second rotating body) so as to be relatively movable in the radial direction. However, the present invention is not limited to this, and the inertia is not limited thereto. The attachment structure of the member to the second rotating body can be changed as appropriate. For example, a support shaft along the axial direction of the second rotator is provided on the axial center side or outer peripheral side of the second rotator, and the inertia member is attached to the second rotator so as to be relatively rotatable around the support shaft. You may make it the structure (The structure which a relative member moves between the radial direction inner side and radial direction outer side of a 2nd rotary body, accompanied by rotational motion).

1 is a schematic front view showing an overall configuration of a motor retractor according to an embodiment of the present invention. It is a disassembled perspective view which shows the whole structure of the motor retractor which concerns on embodiment of this invention. It is a sectional side view which shows the structure of the principal part of the motor retractor which concerns on embodiment of this invention. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, showing the configuration of the first driving force transmission means of the motor retractor according to the embodiment of the present invention. It is a disassembled perspective view which shows the structure of the principal part of the motor retractor which concerns on embodiment of this invention. It is an expanded view which shows the structure of the 1st driving force transmission means of the motor retractor which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structure of the meshing clutch and slip mechanism of the motor retractor which concern on embodiment of this invention. It is a disassembled perspective view which shows the structure of the meshing clutch and slip mechanism of the motor retractor which concern on embodiment of this invention. It is a front view which shows the structure of the meshing clutch of the motor retractor which concerns on embodiment of this invention, and shows the state by which the pawl was arrange | positioned in the cancellation | release position. FIG. 5 is a front view showing the configuration of the meshing clutch of the motor retractor according to the embodiment of the present invention, in which the pawl is arranged at the coupling position and the relative rotation to the other around the axis of the ratchet with respect to the drive gear is restricted. . FIG. 5 is a front view showing the configuration of the meshing clutch of the motor retractor according to the embodiment of the present invention, in which the pawl is disposed at the coupling position and the relative rotation of the drive gear to one side around the axis of the ratchet is restricted. . It is sectional drawing which showed the structure of the 2nd driving force transmission means of the motor retractor which concerns on embodiment of this invention, and followed the 12-12 line of FIG. It is an expanded view which shows the structure of the 2nd driving force transmission means of the motor retractor which concerns on embodiment of this invention.

Explanation of symbols

10 Motor retractor (webbing retractor)
20 Spool (winding shaft)
28 Webbing 48 Motor 54 Meshing clutch 56 Drive gear (second rotating body)
62 Ratchet (first rotating body)
65 Protrusion 66 Pawl 71 Weight (Inertial member)

Claims (5)

Winding the occupant restraining webbing by being rotated in the winding direction, and the winding shaft being rotated in the pulling-out direction by pulling out the webbing;
A first rotating body that is rotated around one axis in conjunction with rotation of the winding shaft in the winding direction and rotated around the axis in conjunction with rotation in the pull-out direction of the winding shaft; ,
A second rotating body provided coaxially and relatively rotatably with respect to the first rotating body;
It is attached to the second rotating body and moves between a connection position that restricts relative rotation of the second rotating body around one axis and the other around the axis relative to the first rotating body and a release position that releases the restriction. With a possible pawl,
The second rotating body is attached to the second rotating body so as to be movable relative to one side and the other side, and is biased to the one side to hold the pawl in the release position, and the second rotating body is set to a predetermined value. An inertia member that rotates around the axis at the above speed to move the pawl to the connecting position when the centrifugal force acting on itself exceeds the biasing force and is moved to the other side;
A motor capable of rotating the second rotating body around one axis and the other around the axis at a speed equal to or higher than the predetermined value;
A webbing take-up device comprising:   One end of the pawl is pivotally supported by the second rotating body, and is rotatable with respect to the second rotating body between the connection position and the release position, and an intermediate portion is connected to the inertia member. 2. The webbing retractor according to claim 1, wherein the other end side is engaged with the first rotating body in a state of being connected and moved to the connecting position.   The webbing take-up device according to claim 2, wherein the pawl is formed by bending a wire-like metal material.   The first rotating body is provided with a protrusion, and the pawl enters the rotation path of the protrusion while being moved to the connection position, and is moved to the release position. The webbing take-up device according to claim 1, wherein the webbing take-up device is retracted out of the rotation path. Winding the occupant restraining webbing by being rotated in the winding direction, and the winding shaft being rotated in the pulling-out direction by pulling out the webbing;
A first rotating body that is rotated around one axis in conjunction with rotation of the winding shaft in the winding direction and rotated around the axis in conjunction with rotation in the pull-out direction of the winding shaft; ,
A second rotating body provided coaxially and relatively rotatably with respect to the first rotating body;
It is attached to the second rotating body so as to be movable relative to one side and the other side, and is biased toward the one side, and the second rotating body is rotated around the axis at a speed equal to or higher than a predetermined value. When the centrifugal force acting on itself exceeds the urging force, the inertial force is moved to the other side, and the inertia of the first rotating body relative to the second rotating body around the axis and the other around the axis is restricted. Members,
A motor capable of rotating the second rotating body around one axis and the other around the axis at a speed equal to or higher than the predetermined value;
A webbing take-up device comprising:

Images