JP2015168352A - webbing take-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a webbing take-up device capable of transmitting rotation force even when a clutch member deforms and slips due to force from a gear.SOLUTION: A facing part 100 of a large gear part 78 is separated from one end surface 98B of a clutch spring 98 gradually toward a radial direction outside of the large gear part 78, and a corner part 100A of the facing part 100 contacts with one end surface 98B of the clutch spring 98, in the webbing take-up device. Therefore, one end surface 98B of the clutch spring 98 does not slip to inside of the large gear part 78 in the radial direction. Therefore, rotation force can be transmitted between one end surface 98B of the clutch spring 98 and the facing part 100 of the large gear part 78 or corner part 100A.

Description

  The present invention relates to a webbing take-up device capable of interrupting transmission of rotational force between a motor and a spool when the webbing is pulled while the motor is driven.

  In the webbing take-up device disclosed in Patent Document 1 below, a rotational force is transmitted between one circumferential end of a friction spring attached to a small-diameter gear and a protruding portion formed in the large-diameter gear, thereby reducing the small-diameter gear and the large-diameter gear. A rotational force is transmitted to and from the radial gear. In such a configuration, when the rotational force is transmitted between the friction spring and the protruding portion, the end of the friction spring is elastically deformed by the force received from the protruding portion. There is a possibility of slipping inward in the radial direction of the radial gear.

JP 2011-88469 A

  An object of the present invention is to obtain a webbing take-up device that can transmit a rotational force even when a clutch member is deformed and slipped by a force from a gear in consideration of the above fact.

  The webbing take-up device according to claim 1, wherein a spool on which the webbing is taken up, a motor for rotating the spool, a first gear provided in a rotation transmission path from the motor to the spool, and the rotation A second gear is provided in the transmission path and is rotatable relative to the first gear, and is attached to the second gear so as to be rotatable integrally with the second gear by an elastic force, and is attached to the first gear. A clutch member that abuts to transmit rotation between the first gear and the second gear, and that blocks the transmission of rotation by rotating relative to the second gear; and the first gear; Limiting means for restricting deformation of the clutch member in a contact cancellation direction in which contact with the clutch member is canceled.

  According to the webbing take-up device according to claim 1, the deformation of the clutch member attached to the second gear and the first gear in a contact canceling direction in which the contact between the first gear and the clutch member is canceled is suppressed by the limiting unit. Is done. Accordingly, the contact between the clutch member and the first gear can be maintained, and the rotational force can be transmitted between the clutch member and the first gear.

  The webbing take-up device according to claim 2 is the webbing take-up device according to claim 1, wherein the limiting means is formed on the first gear so as to be able to contact the clutch member, and is applied to the clutch member. The clutch member can be guided in a direction opposite to the contact cancellation direction by the rotating force or the reaction force.

  In the webbing take-up device according to claim 2, the clutch member is opposite to the contact cancellation direction by the rotational force or reaction force applied to the clutch member by the limiting means formed on the first gear so as to be able to contact the clutch member. It can be guided in the direction. Thereby, the deformation of the clutch member in the contact cancellation direction can be prevented or suppressed, the contact between the clutch member and the first gear can be maintained, and the rotational force can be transmitted between the clutch member and the first gear.

  The webbing take-up device according to claim 3 is the webbing take-up device according to claim 2, wherein the opposing portion formed on the first gear and abutted against the clutch member in the first gear circumferential direction or The contact portion of the clutch member with the facing portion serves as the restricting means so that the rotational force or reaction force applied by the facing portion to the contact portion is directed in a direction opposite to the contact canceling direction. One of the facing portion and the contact portion is inclined with respect to the other.

  In the webbing take-up device according to claim 3, a facing portion is formed on the first gear, the facing portion is brought into contact with the clutch member in the first gear circumferential direction, and the facing portion is subjected to rotational force on the contact portion of the clutch member. Or give reaction force. Here, one of the opposing part and the contact part is opposite to the other so that the rotational force or reaction force applied by the opposing part to the contact part of the clutch member is directed in the direction opposite to the contact cancellation direction. Inclined. The clutch member can be prevented or suppressed from being guided in the contact cancellation direction by the facing portion. Thereby, the deformation of the clutch member in the contact cancellation direction can be prevented or suppressed, the contact between the clutch member and the first gear can be maintained, and the rotational force can be transmitted between the clutch member and the first gear. Further, the rotational force received by the limiting means from the clutch member and the reaction force of the rotational force can be input to the limiting means as a compression load.

  The webbing take-up device according to a fourth aspect is the webbing take-up device according to the third aspect, wherein a corner portion of the facing portion on the abutting cancellation direction side is more than a center of the abutting cancellation direction in the abutting portion. It is set on the contact cancellation direction side.

  In the webbing take-up device according to the fourth aspect, the corner of the facing portion on the contact cancellation direction side is set to the contact cancellation direction side of the contact cancellation direction center of the contact portion of the clutch member. For this reason, it can further prevent or suppress that the clutch member is guided in the contact cancellation direction by the facing portion. Thereby, the deformation of the clutch member in the contact cancellation direction can be prevented or suppressed, the contact between the clutch member and the first gear can be maintained, and the rotational force can be transmitted between the clutch member and the first gear.

  The webbing take-up device according to claim 5 is the webbing take-up device according to any one of claims 1 to 4, wherein the clutch member has less than one turn from one end to the other end in the circumferential direction. Then, the inner peripheral part or the outer peripheral part is pressed against the rotating body elastically rotating integrally with the second gear or the second gear.

  According to the webbing take-up device according to claim 5, the clutch member whose inner peripheral portion or outer peripheral portion is elastically pressed against the second gear or the rotating body that rotates integrally with the second gear has one circumferential end. The other end is less than one turn. For this reason, the axial direction dimension of a clutch member can be shortened. Thereby, the axial direction dimension of the 2nd gear or rotary body with which a clutch member is press-contacted can be shortened.

  As described above, in the webbing take-up device according to the present invention, the rotational force can be transmitted even if the clutch member is deformed and slips due to the force from the first gear.

It is a disassembled perspective view of the webbing winding device concerning a 1st embodiment. (A) is an exploded perspective view of a first gear, a second gear, a rotor, and a clutch member, and (B) is a perspective view of the rotor as viewed from the side opposite to (A). FIG. 3 is a cross-sectional view showing a first gear corresponding to a cross section taken along line 3-3 in FIG. 2A and related parts assembled thereto. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is sectional drawing corresponding to FIG. 4 which shows 2nd Embodiment.

<Configuration of First Embodiment>
A webbing retractor 10 according to each embodiment of the present invention will be described with reference to FIGS. 1 to 5. In each figure, the arrow FR indicates the front side in the front-rear direction of the webbing take-up device 10, the arrow LH indicates the left side in the left-right direction of the webbing take-up device 10, and the arrow UP indicates the upper side in the vertical direction of the webbing take-up device 10.

(Overall configuration of webbing take-up device 10)
As shown in FIG. 1, the webbing retractor 10 according to the first embodiment includes a frame 12 that is fixed to a vehicle body constituent member such as a skeleton member or a reinforcing member of a vehicle. The frame 12 includes leg plates 14 and 16 facing in the left-right direction, and a spool 18 is provided between the leg plates 14 and 16. The spool 18 is formed in a substantially cylindrical shape whose axial direction is along the opposing direction of the leg plates 14 and 16, and the longitudinal direction proximal end side of the webbing 20 for mounting the occupant is locked. The spool 18 can be rotated around the central axis in the winding direction and the opposite drawing direction. When the spool 18 is rotated in the winding direction, the webbing 20 is wound in layers on the outer periphery of the spool 18. It is done.

  A housing 24 of a lock mechanism 22 is attached to the leg plate 14, and one end of the spool 18 is rotatably supported by the housing 24. Various parts constituting the VSIR mechanism and the WSIR mechanism are provided inside the housing 24. The VSIR mechanism is operated in a vehicle sudden deceleration state at the time of a vehicle collision. On the other hand, the WSIR mechanism is operated when the rotational acceleration in the pull-out direction of the spool 18 exceeds a predetermined magnitude. By operating the VSIR mechanism or the WSIR mechanism, a lock member (not shown) constituting the lock mechanism 22 is operated, and rotation of the spool 18 in the pull-out direction is prevented.

  Further, the spool 18 is provided with a force limiter mechanism. When rotation of the spool 18 in the pulling direction is blocked by the lock member of the lock mechanism 22 and the rotational force in the pulling direction of the spool 18 exceeds a predetermined magnitude, the energy absorbing member of the force limiter mechanism is deformed and the spool is deformed. 18 is rotated in the pull-out direction. The webbing 20 is pulled out of the spool 18 by the amount of rotation of the spool 18 in the pull-out direction, and part of the rotational force of the spool 18 is subjected to deformation of the energy absorbing member and absorbed. A pretensioner 26 is provided on the side of the leg plate 14. The pretensioner 26 is activated in the event of a vehicle emergency and forcibly rotates the spool 18 in the winding direction.

  On the other hand, a spring housing 28 is provided outside the leg plate 16. Inside the spring housing 28 is provided a tip end side of a shaft member 30 that penetrates the leg plate 16, and the shaft member 30 is rotatably supported by the spring housing 28. The shaft member 30 is provided coaxially with the spool 18 and is connected to the spool 18 to prevent relative rotation with respect to the spool 18. A spiral spring (not shown) is provided inside the spring housing 28, and the shaft member 30 is urged in the winding direction by the spiral spring. A gear housing 32 is provided between the leg plate 16 and the spring housing 28. The gear housing 32 is formed in a concave shape opening toward the right side, and the opening side of the gear housing 32 is closed by a plate 34 provided between the spring housing 28 and the gear housing 32.

  Further, a ratchet wheel 56 is provided inside the gear housing 32. The ratchet wheel 56 is provided coaxially with the shaft member 30 and is prevented from rotating relative to the shaft member 30. A cylindrical support portion 36 is formed inside the gear housing 32. The support portion 36 is formed coaxially with the spool 18, and the shaft member 30 passes therethrough. A clutch gear 38 is rotatably supported by the support portion 36. A pawl 42 is rotatably provided inside the clutch gear 38. A return spring 44 is provided inside the clutch gear 38, and the pawl 42 is urged so that the tip end side of the pawl 42 rotates outward in the radial direction of the clutch gear 38.

  In addition, holding rings 46 and 48 are formed outside the support portion 36. The holding rings 46 and 48 are formed coaxially with the support portion 36, and a holding ring 48 is formed outside the holding ring 46. Between the retaining rings 46, 48, the base 52 of the contact member 50 is contained. The base 52 of the contact member 50 is in sliding contact with the outer surface of the holding ring 46 and the inner surface of the holding ring 48, and the contact member 50 is guided by the holding rings 46 and 48 and can rotate around the support portion 36. .

  A contact portion 54 extends to the right from the base 52 of the contact member 50, and the contact portion 54 faces the tip end side of the pawl 42 on the winding direction side of the pawl 42. When the clutch gear 38 is rotated in the winding direction, the tip end side of the pawl 42 is brought into contact with the contact portion 54 of the contact member 50. When the clutch gear 38 is rotated in the winding direction in this state, the pawl 42 is rotated against the urging force of the return spring 44, whereby the tip end side of the pawl 42 is engaged with the ratchet wheel 56. Further, when the clutch gear 38 is further rotated in the winding direction in this state, the contact member 50 is pressed by the pawl 42 and rotated around the support portion 36 together with the clutch gear 38.

  The gear housing 32 is formed with three shafts 58, 60, and 62. These shafts 58 to 62 include a gear 66, a two-stage gear 68, and a two-stage gear 70 that form a reduction gear train 64. Is supported rotatably. The gear 66 is engaged with the clutch gear 38 and the small gear portion 76 of the two-stage gear 68, and the large gear portion 78 of the two-stage gear 68 is engaged with the small gear portion 80 of the two-stage gear 70.

  On the other hand, a motor 84 is provided below the spool 18 between the leg plates 14 and 16. The motor 84 is electrically connected to an ECU (not shown) as control means, and is further electrically connected to a battery (not shown) mounted on the vehicle via the ECU. The ECU is electrically connected to a forward monitoring device (not shown) that measures the distance to other vehicles and obstacles ahead of the vehicle on which the webbing take-up device 10 is mounted. When the value is less than the value, the motor 84 is driven forward by the ECU.

  An output shaft (not shown) of the motor 84 passes through the leg plate 16 and the gear housing 32, and a pinion gear (not shown) that meshes with the large gear portion 82 of the two-stage gear 70 at the tip of the output shaft of the motor 84. Is provided. The pinion gear, the two-stage gear 70, the two-stage gear 68, the gear 66, and the clutch gear 38 of the output shaft of the motor 84 constitute a rotation transmission path from the motor 84 to the spool 18, and the forward driving force of the motor 84 is The speed is reduced by the reduction gear train 64 and transmitted to the clutch gear 38, whereby the clutch gear 38 is rotated in the winding direction.

(Configuration of overload release mechanism)
Incidentally, the two-stage gear 68 of the reduction gear train 64 constitutes an overload release mechanism. As shown in FIG. 2, a shaft portion 86 projects from a small gear portion end surface 76 </ b> A on the right side of the small gear portion 76 as the second gear of the two-stage gear 68. The shaft portion 86 is formed coaxially with the small gear portion 76 and has an outer shape smaller than that of the small gear portion 76. A rotation stop 88 is formed to protrude from the shaft end surface 86A on the right side of the shaft 86. The anti-rotation portion 88 has a non-circular shape such as a spline shape whose outer shape is smaller than that of the shaft portion 86. The small gear portion 76, the shaft portion 86, and the anti-rotation portion 88 have a stepped shape whose outer shape decreases toward the anti-rotation portion 88.

  On the other hand, the large gear portion 78 as the first gear of the two-stage gear 68 is formed on the outer periphery of the cylindrical portion 90. A disc-shaped middle bottom portion 92 is formed in the axially intermediate portion of the large gear portion 78, and a circular hole 94 is formed in the shaft core portion of the middle bottom portion 92. The shaft portion 86 of the small gear portion 76 passes through the circular hole 94, and the middle bottom portion 92 contacts the small gear portion end surface 76 </ b> A, so that the large gear portion 78 can rotate relative to the small gear portion 76. It is supported.

  A concave housing portion 96 is formed on the right side of the middle bottom portion 92, and a clutch spring 98 as a clutch member is provided in the housing portion 96. The clutch spring 98 is formed in a substantially C-shape in which the axial center of a metal bar having a circular cross section is bent and formed into a circular shape, with one end to the other end in the circumferential direction being less than one turn and discontinuous between both ends. Further, one end side of the clutch spring 98 is a straight portion 98 </ b> A extending linearly in a tangential direction with respect to the circular axis of the clutch spring 98. The accommodating portion 96 is formed with a facing portion 100 as a limiting means corresponding to one end surface 98B as a contact portion of the linear portion 98A of the clutch spring 98. The facing portion 100 is formed around the central axis of the large gear portion 78 at a certain angle (90 degrees in the present embodiment). In a state where the clutch spring 98 is housed in the housing portion 96, one of these facing portions 100 faces the one end surface 98 </ b> B of the clutch spring 98. One end surface 98 </ b> B of the clutch spring 98 is a surface perpendicular to the central axis C in the straight portion 98 </ b> A of the clutch spring 98.

  Further, the facing portion 100 is inclined at an angle of θ so as to gradually move away from the one end surface 98B toward the radially outer side of the large gear portion 78 with respect to the one end surface 98B of the clutch spring 98. The corner portion 100A on the radially inner side of the gear portion 78 is in contact with the one end surface 98B. Further, the corner portion 100A of the facing portion 100 is in contact with the one end surface 98B on the inner side of the large gear portion 78 in the radial direction on the one end surface 98B of the clutch spring 98.

  On the other hand, the two-stage gear 68 includes a rotor 102 as a rotating body. The rotor 102 includes a cylindrical portion 104. A left end portion of the cylindrical portion 104 is closed by a bottom portion 106, and a flange portion 108 extends outward from the right end portion in the radial direction of the rotor 102. Thus, the rotor 102 has a hat shape that is one aspect of a bottomed cylindrical shape as a whole, and is formed by press-molding a metal flat plate. A hole 110 is formed in the bottom 106 of the rotor 102. The shape of the hole portion 110 is the same as that of the rotation stop portion 88 of the small gear portion 76, and when the rotation stop portion 88 passes through the hole portion 110, relative rotation of the rotor 102 with respect to the small gear portion 76 is prevented. The

  In addition, in a state where the bottom portion 106 of the rotor 102 is in contact with the shaft portion end surface 86A of the shaft portion 86, the distal end side of the anti-rotation portion 88 passes through the hole portion 110 and protrudes to the right side of the bottom portion 106. As shown in FIG. 3, a caulking portion 112 is formed on the distal end side of the anti-rotation portion 88. The caulking portion 112 is formed by the caulking portion 88 being pressed from the tip and caulked. The outer shape of the caulking portion 112 is larger than that of the hole portion 110, thereby preventing the rotor 102 from moving to the right side. In this state, the middle bottom portion 92 of the large gear portion 78 is sandwiched between the bottom portion 106 of the rotor 102 and the small gear portion 76, whereby the two-stage gear 68 of the large gear portion 78 with respect to the small gear portion 76 is axially disposed. Movement is restricted.

  Specifically, the axial dimension of the shaft portion 86 between the small gear portion end surface 76A of the small gear portion 76 and the shaft portion end surface 86A of the shaft portion 86 is the same as the thickness of the middle bottom portion 92 of the large gear portion 78 or It is slightly larger. For this reason, even if the middle bottom portion 92 is sandwiched between the bottom portion 106 of the rotor 102 and the small gear portion end surface 76A of the small gear portion 76, the middle bottom portion 92 is not pressed against the bottom portion 106 or the small gear portion end surface 76A. The large gear portion 78 is freely rotatable relative to the small gear portion 76 and the rotor 102. In this state, the accommodating portion 96 provided with the clutch spring 98 of the large gear portion 78 is closed by the flange portion 108 of the rotor 102.

  A clutch spring 98 is attached to the cylindrical portion 104 of the rotor 102 so as to be wound elastically, and the clutch spring 98 is pressed against the outer surface of the cylindrical portion 104. For this reason, the clutch spring 98 and the rotor 102 are integrally rotated by friction between the clutch spring 98 and the cylindrical portion 104.

<Operation and effect of the present embodiment>
Next, the operation and effect of the present embodiment will be described.

  In the webbing take-up device 10, the distance to other vehicles and obstacles ahead is measured by the front monitoring device, and when the distance becomes less than a certain value, the motor 84 is driven forward by the ECU. The forward rotation driving force of the motor 84 is transmitted to the large gear portion 78 of the two-stage gear 68 via the pinion gear of the output shaft of the motor 84 and the two-stage gear 70, so that the large gear section 78 rotates in the direction of arrow B in FIG. Is done. When the large gear portion 78 is rotated and the one end surface 98B of the clutch spring 98 is pressed against the corner portion 100A of the facing portion 100 of the large gear portion 78, the rotor 102 is rotated together with the clutch spring 98. Thus, when the small gear portion 76 of the two-stage gear 68 is rotated, the rotation of the small gear portion 76 is transmitted to the clutch gear 38 via the gear 66, and the clutch gear 38 is rotated in the winding direction.

  As a result, when the pawl 42 of the clutch gear 38 comes into contact with the contact portion 54 of the contact member 50, the pawl 42 is rotated by the pressing reaction force from the contact portion 54, and the tip end side of the pawl 42 is ratchet. Engage with the wheel 56. As a result, the rotation of the clutch gear 38 is transmitted to the spool 18 via the ratchet wheel 56 and the shaft member 30, and the spool 18 is rotated in the winding direction. Thus, when the webbing 20 attached to the occupant's body is wound on the spool 18, the slack of the webbing 20 is removed.

  On the other hand, for example, when the vehicle is decelerated, the occupant's body attempts to move inertially toward the front of the vehicle, and the webbing 20 is pulled by the occupant's body. In this state, when the motor 84 is driven forward, a rotational force opposite to the driving force of the motor 84 is transmitted from the spool 18 to the motor 84 side. As a result, the pressing force applied from one end face 98B of the clutch spring 98 applied to the corner portion 100A of the facing portion 100 formed in the large gear portion 78 of the two-stage gear 68 is changed between the clutch spring 98 and the cylindrical portion 104 of the rotor 102. When the slip torque (maximum frictional force) is exceeded, the clutch spring 98 is expanded in diameter, and slip occurs between the clutch spring 98 and the cylindrical portion 104 of the rotor 102. As a result, the load applied to the meshing portions of the clutch gear 38, the gears 66, 68, 70 of the reduction gear train 64 and the pinion gear of the output shaft of the motor 84 can be reduced.

  Here, in the present embodiment, the facing portion 100 is inclined at an angle of θ so as to gradually move away from the one end surface 98B of the clutch spring 98 toward the outer side in the radial direction of the large gear portion 78. The portion 100A is brought into contact with one end surface 98B of the clutch spring 98. For this reason, the clutch spring 98 is not elastically deformed radially inward by the opposing portion 100 in the large gear portion 78 which is the contact cancellation direction, and the one end surface 98B of the clutch spring 98 slides radially inward of the large gear portion 78. There is nothing.

  In addition, when a load in the rotational tangential direction of the large gear portion 78 is applied between the one end surface 98B of the clutch spring 98 and the corner portion 100A of the facing portion 100, the component force of this load applies the straight portion 98A of the clutch spring 98. It acts to elastically deform the large gear portion 78 radially outward, which is the direction opposite to the contact cancellation direction. As a result, the one end surface 98B is guided so that the clutch spring 98 is elastically deformed outward in the radial direction of the large gear portion 78 (the direction opposite to the contact cancellation direction), and the one end surface 98B of the clutch spring 98 is the diameter of the large gear portion 78. Slide outward in the direction. In the present embodiment, the facing portion 100 is a part of the inner peripheral surface of the accommodating portion 96. For this reason, even if the one end surface 98B of the clutch spring 98 slides outward in the radial direction of the large gear portion 78, the contact between the one end surface 98B and the facing portion 100 or the corner portion 100A is maintained, and the one end surface 98B of the clutch spring 98 is maintained. And a rotational force can be transmitted between the opposing portion 100 or the corner portion 100A of the large gear portion 78.

  Moreover, the corner portion 100A of the facing portion 100 is in contact with the one end surface 98B on the inner side of the large gear portion 78 in the radial direction on the one end surface 98B of the clutch spring 98. For this reason, the slipping direction when the one end surface 98B of the clutch spring 98 slips with respect to the corner portion 100A of the facing portion 100 is likely to be radially outward of the large gear portion 78. Thereby, it is possible to more effectively prevent or suppress the end surface 98B of the clutch spring 98 from slipping inward in the radial direction of the large gear portion 78.

  Further, in the present embodiment, one end surface 98B of the clutch spring 98 is in contact with the corner portion 100A of the facing portion 100, and one end of the clutch spring 98 is not in contact with the surface of the facing portion 100. In addition, the rotational force and reaction force from the one end surface 98 </ b> B of the clutch spring 98 are input to the corner portion 100 </ b> A of the facing portion 100 as a compression load. For this reason, it is possible to prevent or suppress the opposing portion 100 from being deformed by the pressing force or pressing reaction force from the one end surface 98B of the clutch spring 98.

  On the other hand, in the present embodiment, the shape of the clutch spring 98 is formed in a substantially C-shape that is less than one turn from one end to the other end in the circumferential direction and is discontinuous between both ends. For this reason, the axial length of the cylindrical portion 104 of the rotor 102 only needs to be equal to or greater than the wire diameter (cross-sectional diameter) of the clutch spring 98. As a result, the two-stage gear 68 can be thinned.

  In the present embodiment, the one end surface 98B of the clutch spring 98 is in contact with the corner portion 100A of the facing portion 100 of the large gear portion 78. However, the corner portion 100A only needs to be positioned on the inner side of the center of the large gear portion 78 in the radial direction on the one end surface 98B of the clutch spring 98. Therefore, the configuration may be such that the one end surface 98B of the clutch spring 98 is positioned on the radially outer side of the large gear portion 78 with respect to the corner portion 100A and abuts against the opposing portion 100.

  Further, in the present embodiment, one end surface 98B as a contact portion of the clutch spring 98 is a surface perpendicular to the central axis C in the linear portion 98A, and the facing portion 100 is radially outward of the large gear portion 78. It was the structure inclined so that it might space apart from the one end surface 98B. However, the one end surface 98B of the clutch spring 98 and the facing portion 100 of the large gear portion 78 are not limited to such a relationship. For example, the one end surface 98B of the clutch spring 98 is inclined with respect to the central axis C, and the one end surface 98B is inclined so as to be separated from the facing portion 100 radially outward in the large gear portion 78. In such a configuration, the one end surface 98B as the contact portion serves as the limiting means. Thus, if the one end surface 98B of the clutch spring 98 and the facing portion 100 of the large gear portion 78 are separated from the facing portion 100 toward the radially outer side of the large gear portion 78, the one end surface 98B and the facing portion will be described. Any of 100 may be inclined.

  Further, in the present embodiment, the opposed portion 100 of the large gear portion 78 is used as the limiting means, and the linear portion 98A of the clutch spring 98 is brought into contact with the corner portion 100A of the opposed portion 100 due to a load component. The one end face 98B is configured to slide outward in the radial direction of the large gear portion 78 by being elastically deformed outward in the radial direction of the large gear portion 78, which is the direction opposite to the direction. However, even if the limiting means is not configured to guide the linear portion 98A of the clutch spring 98 to the radially outer side of the large gear portion 78, the linear portion 98A of the clutch spring 98 is in the radial direction of the large gear portion 78, which is the contact cancellation direction. What is necessary is just to be able to restrict moving inward. Hereinafter, a modified example of such a limiting means will be described as a second embodiment.

<Second Embodiment>
In the present embodiment shown in FIG. 5, a housing portion 122 is formed in the large gear portion 78 instead of the housing portion 96. Unlike the housing portion 96, the housing portion 122 is formed with only one facing portion 100. A stopper 124 as a limiting means is formed on the inner peripheral surface of the housing portion 122. The stopper 124 is formed on one end face 98B side of the straight portion 98A of the clutch spring 98 housed in the housing portion 122, and faces the straight portion 98A on the radially inner side of the large gear portion 78. For this reason, the elastic deformation of the linear portion 98A of the clutch spring 98 inwardly in the radial direction of the large gear portion 78 is limited by the stopper 124, whereby the contact between the one end surface 98B of the clutch spring 98 and the opposing portion 100 of the housing portion 122 is restricted. Maintain contact.

  In place of such a stopper 124, as shown by a two-dot chain line in FIG. 5, a restricting means is provided on the middle bottom 92 of the large gear portion 78 on the radially inner side of the large gear portion 78 of the linear portion 98A of the clutch spring 98. The protrusion 126 may be formed, and the protrusion 126 may restrict elastic deformation of the linear portion 98A of the clutch spring 98 inward in the radial direction of the large gear portion 78.

  Further, in each of the above-described embodiments, the contact cancellation direction is the inside of the large gear portion 78 in the radial direction. However, for example, the clutch spring is elastically pressed against the inner surface of the cylindrical portion formed on the second gear or the rotor, and the load transmitting portion formed on the first gear is the cylindrical portion of the second gear or the rotor. If the one end of the clutch spring is in contact with each other, the contact cancellation direction is the second gear radial direction outer side. As described above, the contact cancellation direction may be set in a direction other than the radial inner side of the large gear portion 78.

  Further, in each of the above-described embodiments, the clutch spring 98 as a clutch member is elastically pressed against the cylindrical portion 104 of the rotor 102 as a rotating body and is mounted on the cylindrical portion 104. However, the clutch spring 98 may be elastically pressed against the small gear portion 76 as the second gear and attached to the small gear portion 76.

  In each of the above embodiments, the large gear portion 78 to which the driving force of the motor 84 is input in the two-stage gear 68 is used as the first gear, and the small gear portion 76 that outputs the rotational force to the spool 18 side. The second gear. However, the configuration may be such that the driving force of the motor is input to the second gear and the rotational force is output from the first gear to the spool.

  Further, in each of the above-described embodiments, the large gear portion 78 as the first gear is larger than the small gear portion 76 as the second gear and has a larger number of teeth. However, the second gear may be larger than the first gear and have a larger number of teeth, and the size and the number of teeth of the first gear and the second gear are not limited at all.

10 Webbing take-up device 18 Spool 20 Webbing 38 Clutch gear (rotation transmission path)
66 Gear (Rotation transmission path)
68 Two-stage gear (rotation transmission path)
70 Two-stage gear (rotation transmission path)
76 Small gear (second gear)
76A End face of small gear section 78 Large gear section (first gear)
84 Motor 98 Clutch spring (clutch member)
98B One end surface (contact part, limiting means)
100 Opposing part (limitation means)
100A Corner 102 Rotor (Rotating body)
124 Stopper (Limiting means)
126 Protrusion (restriction means)

Claims (5)

A spool on which the webbing is wound,
A motor for rotating the spool;
A first gear provided in a rotation transmission path from the motor to the spool;
A second gear provided in the rotation transmission path and rotatable relative to the first gear;
It is attached to the second gear so as to be rotatable integrally with the second gear by elastic force, and is in contact with the first gear to transmit rotation between the first gear and the second gear, A clutch member that blocks transmission of the rotation by rotating relative to the second gear;
Limiting means for limiting deformation of the clutch member in a contact cancellation direction in which contact between the first gear and the clutch member is canceled;
A webbing take-up device comprising:   The restricting means is formed on the first gear so as to be able to contact the clutch member, and is capable of guiding the clutch member in a direction opposite to the contact cancellation direction by a rotational force or a reaction force applied to the clutch member. The webbing take-up device according to claim 1.   The opposed portion formed on the first gear and abutted against the clutch member in the first gear circumferential direction or the abutted portion with the opposed portion of the clutch member serves as the restricting means, and the opposed portion is the contact portion. 3. The opposed portion and the contact portion are inclined with respect to the other so that the rotational force or reaction force applied to the contact portion is directed in a direction opposite to the contact cancellation direction. The webbing take-up device described.   The webbing take-up device according to claim 3, wherein a corner portion on the contact cancellation direction side of the facing portion is set closer to the contact cancellation direction side than the center of the contact cancellation direction in the contact portion.   The clutch member has less than one turn from one end to the other end in the circumferential direction, and the inner peripheral portion or the outer peripheral portion is pressed against the rotating body elastically rotating integrally with the second gear or the second gear. The webbing take-up device according to any one of claims 1 to 4.

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