JP2019077345A - Webbing take-up device - Google Patents

Abstract

To maintain an engagement state between a lock part and an engaged part when a load is input from webbing to a spool.SOLUTION: A webbing take-up device includes: a spool which takes up webbing attached to an occupant and is rotated in a drawing direction by the webbing being drawn; and a lock base 22 which is provided so as to be rotatable with rotation of the spool. The webbing take-up device includes a lock plate 28 which is supported by the lock base 22 and moved relative to the lock base 22 to be engaged with a ratchet tooth 30C and restrict the lock base 22 from rotating in the drawing direction and in which at least a portion facing the lock base 22 is formed into a protruding shape.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a webbing retractor.

  Patent Document 1 below discloses a webbing take-up device in which the withdrawal of the webbing from the spool is limited at the time of rapid deceleration of the vehicle. The webbing take-up device described in this document has a spool on which the webbing is wound, a lock base rotatably provided integrally with the spool, a lock plate supported by the lock base, and the spool supported. And a frame provided with ratchet teeth. Then, at the time of rapid deceleration of the vehicle, the lock plate moves relative to the lock base and the lock plate is engaged with the ratchet teeth of the frame, so that the rotation of the spool is limited and the webbing is pulled out from the spool. It is supposed to be restricted.

  By the way, in the webbing take-up device in which withdrawal of the webbing from the spool is limited at the time of rapid deceleration of the vehicle, the lock plate (lock portion) and the ratchet teeth (engaged portion) even when load is input from the webbing to the spool. It is desirable to maintain the engagement with the

Unexamined-Japanese-Patent No. 2004-196149

  In view of the above facts, it is an object of the present invention to provide a webbing retractor capable of maintaining the engagement between the lock portion and the engaged portion even when a load is input from the webbing to the spool. .

  The webbing take-up device according to the first aspect is provided with a spool on which a webbing to be attached to an occupant is taken up and is rotated in the pull-out direction by pulling out the webbing, and can be rotated with the rotation of the spool. The base portion is supported by the base portion, and is moved with respect to the base portion to be engaged with the engaged portion to restrict the rotation of the base portion in the pulling direction, so as to face the base portion. And at least a part of the portion in the form of a lock formed in a convex shape.

  The webbing retractor according to the second aspect is the webbing retractor according to the first aspect, wherein one side of the base portion in the rotation axis direction of the portion facing the base portion in the lock portion is convex. It is formed.

  The webbing retractor according to the third aspect is the webbing retractor according to the second aspect, wherein the other side of the base portion in the rotational axis direction is open and the lock portion is disposed in the base portion. The lock portion disposing recess is formed.

  In the webbing retractor according to the fourth aspect, in the webbing retractor according to the third aspect, a cover member covering an open end side of the lock portion disposition concave portion is attached to the base portion.

  A webbing retractor according to a fifth aspect is the webbing retractor according to any one of the first aspect to the fourth aspect, wherein a pivot portion supporting the lock portion in a tiltable manner is provided on the base portion. In the state where the lock portion is provided and supported by the support shaft portion, the convexly formed portion of the lock portion is separated from the base portion.

  A webbing retractor according to a sixth aspect is the webbing retractor according to any one of the first to fifth aspects, wherein the lock portion has a plate shape whose thickness direction corresponds to the rotational axis direction of the base portion. In the lock portion, the other portion of the base portion facing the base portion in the rotation axis direction is a fracture surface, and the portion of the base portion on the rotation axis direction is the fracture. It is set as the shear surface which protrudes toward the said base part side rather than a cross section.

  According to the webbing retractor of the first aspect, when the spool is rotated in the pull-out direction by pulling out the webbing, the base portion is rotated in the pull-out direction along with the rotation of the spool. In addition, when the lock portion moves relative to the base portion and is engaged with the engaged portion, the rotation of the base portion in the pull-out direction is restricted. Thus, the rotation of the spool in the withdrawal direction is limited, and the withdrawal of the webbing from the spool is limited. Here, in the webbing retractor according to the first aspect, at least a part of the portion facing the base portion in the lock portion is formed in a convex shape. Therefore, when a load is input from the webbing to the spool in a state where the lock portion is engaged with the engaged portion, and a portion of the lock portion facing the base portion is pressed toward the base portion, The convexly formed portion in the lock portion bites into the base portion. Thereby, the displacement of the lock portion relative to the base portion can be restricted. As a result, even when a load is input from the webbing to the spool, the engagement between the lock portion and the engaged portion can be maintained.

  According to the webbing retractor relating to the second aspect, one side of the base portion of the lock portion facing the base portion in the rotational axis direction is formed in a convex shape. Thus, when a load is input from the webbing to the spool in a state where the lock portion is engaged with the engaged portion, the displacement of the base portion relative to the base portion relative to the base in the rotational axis direction with respect to the base portion is restricted. be able to.

  According to the webbing retractor relating to the third aspect, the lock portion is disposed in the lock portion disposition recess formed in the base portion. In addition to this, one side of the rotation axis direction of the base portion of the portion facing the base portion in the lock portion is formed in a convex shape. Thus, when a load is input from the webbing to the spool in a state in which the lock portion is engaged with the engaged portion, the lock portion is displaced in the direction to be pulled out from the lock portion disposition recess formed in the base portion. Can be suppressed.

  According to the webbing retractor of the fourth aspect, the lock portion is disposed in the lock portion disposition recess formed in the base portion, and the open end side of the lock portion disposition recess is covered by the cover member There is. Here, one side of the rotation axis direction of the base portion of the portion facing the base portion in the lock portion is formed in a convex shape. Thus, when a load is input from the webbing to the spool in a state in which the lock portion is engaged with the engaged portion, the lock portion is pulled out from within the lock portion disposition recess formed in the base portion. It is possible to suppress displacement to the cover member side. Thereby, the load input from the lock portion to the cover member is reduced, and the thickness of the cover member can be reduced.

  According to the webbing retractor relating to the fifth aspect, the lock portion is tiltably supported by the support shaft portion provided on the base portion. Then, when the lock portion is tilted with respect to the base portion and engaged with the engaged portion, the rotation of the base portion in the pull-out direction is restricted. Thus, the rotation of the spool in the withdrawal direction is limited, and the withdrawal of the webbing from the spool is limited. In addition, even if the load is input from the webbing to the spool in a state where the lock portion is engaged with the engaged portion and the support shaft portion is deformed, the convex portion of the lock portion is the base portion. Swallow. Thereby, the displacement of the lock portion relative to the base portion can be restricted. As a result, even when a load is input from the webbing to the spool, the engagement between the lock portion and the engaged portion can be maintained.

  According to the webbing retractor relating to the sixth aspect, as an example, the lock portion can be formed by pressing the plate-like member. Then, a portion facing the base portion in the lock portion is formed in a convex shape by the fracture surface and the shear surface which are generated at the end portion of the lock portion (the portion facing the base portion in the lock portion) by pressing. Can.

It is a side view showing a webbing take-up device. It is the front view which looked at the webbing winding device from the sensor side. It is a front view corresponding to Drawing 2 showing a webbing winding device, and illustration of a sensor mechanism is omitted. FIG. 5 is a cross-sectional view showing a cross section of the webbing retractor taken along line 4-4 shown in FIG. 3; It is a front view showing a lock plate. FIG. 6 is a cross-sectional view showing a cross section of the lock plate cut along line 6-6 shown in FIG. 5; It is sectional drawing which shows the lock plate etc. which were accommodated in the lock plate accommodating part. It is sectional drawing corresponding to FIG. 7 when a load is input into a lock plate and a support shaft deform | transforms. It is sectional drawing corresponding to FIG. 8 when load is input into a lock plate, a support shaft deform | transforms, and a lock plate deform | transforms further. It is sectional drawing which shows the lock plate of a 2nd form. It is sectional drawing which shows the lock plate of a 3rd form.

  A webbing retractor according to an embodiment of the present invention will be described with reference to FIGS. The arrow Z direction, the arrow R direction, and the arrow C direction appropriately shown in the drawing respectively indicate the rotational axis direction, rotational radial direction, and rotational circumferential direction of the spool. Further, hereinafter, when simply indicating the axial direction, the radial direction and the circumferential direction, unless otherwise noted, the rotational axis direction, the rotational radial direction and the circumferential direction of rotation of the spool are indicated.

  As shown in FIGS. 1 and 4, the webbing take-up device 10 includes a metal frame 12. The frame 12 is fixed to a pillar that constitutes a vehicle body skeleton of a vehicle, a seat cushion frame that constitutes a skeleton of a vehicle seat, and the like. Further, as shown in FIG. 4, the frame 12 includes leg plates 12 </ b> A and leg plates 12 </ b> B which are disposed to be mutually spaced apart in the axial direction. In the leg plate 12A and the leg plate 12B, circular insertion holes 12C and 12D through which a part of the following spool 14 is inserted are formed.

  The spool 14 is made of metal and formed in a substantially cylindrical shape, the majority of which is disposed between the leg plate 12A and the leg plate 12B of the frame 12. A spring housing (not shown) having a spring (not shown) for urging the spool 14 in the winding direction (arrow C direction) on the other axial direction side (opposite to the arrow Z direction) of the spool 14 Is arranged. The spring housing 18 is attached to the outer surface side (outside of the frame 12) of the leg plate 12A of the frame 12.

  Further, the spool 14 is provided with a take-up portion 14B on which a webbing (not shown) is wound, and a longitudinal direction base end portion of the webbing formed in a long strip shape is engaged with the take-up portion 14B. . Then, as the spool 14 is rotated in the winding direction (arrow C direction), the webbing is taken up from the base end side in the longitudinal direction onto the take-up portion 14B of the spool 14 and the webbing is pulled out from the spool 14 Then, the spool 14 is rotated in the withdrawal direction (opposite to the arrow C). Further, a torsion shaft (not shown) is inserted into the axial center of the spool 14.

  Further, the front end side of the webbing in the longitudinal direction extends from the spool 14 to the upper side of the vehicle, and the front end side in the longitudinal direction of the webbing passes through a slit hole formed in a through anchor (not shown) on the vehicle upper side of the frame 12 It has been folded down.

  The longitudinal tip of the webbing is anchored to an anchor plate (not shown). The anchor plate is formed of a metal plate material such as steel, and is fixed to a floor portion (not shown) of the vehicle or a frame member or the like of a sheet (not shown) corresponding to the webbing retractor 10.

  A seat belt device for a vehicle to which the webbing retractor 10 is applied includes a buckle device (not shown). The buckle device is provided on the inner side in the vehicle width direction of the sheet to which the webbing retractor 10 is applied. The webbing is mounted on the occupant's body by the tongue (not shown) provided on the webbing being engaged with the buckle device while the webbing is wound around the body of the occupant seated on the seat.

  As shown in FIGS. 3 and 4, a locking mechanism 20 is provided on the outer surface side (outside of the frame 12) of the leg plate 12 </ b> B of the frame 12. The lock mechanism 20 includes a metal lock base 22 as a base portion and a metal lock plate 28 as a lock portion supported by the lock base 22. The lock base 22 is provided coaxially with the spool 14 on one side in the axial direction with respect to the spool 14. The lock base 22 can be rotated integrally with the spool 14 by being connected to the spool 14 via a metal connection member 24 and a torsion shaft.

  Further, as shown in FIGS. 1 and 2, the lock mechanism 20 includes a sensor mechanism 44. The sensor mechanism 44 is operated at the time of a vehicle emergency such as at the time of a collision of a vehicle or a rapid deceleration. When the sensor mechanism 44 is actuated, the rotation of the lock base 22 in the pull-out direction (the pull-out direction of the spool 14) is restricted, as described in detail below.

  Further, as shown in FIG. 3 and FIG. 4, a metal cover plate 30 is fixed to the leg plate 12 B of the frame 12. The cover plate 30 and the leg plate 12B of the frame 12 form a rack accommodating portion 34 in which most of the lock base 22 and the connecting member 24 are disposed.

  The cover plate 30 is recessed on the side opposite to the side of the frame 12 and is provided with a plate portion 30A axially opposed to the leg plate 12B of the frame 12. A ratchet hole 30B is formed through the plate portion 30A, and the lock base 22 of the lock mechanism 20 penetrates the ratchet hole 30B of the cover plate 30. When the sensor mechanism 44 of the lock mechanism 20 is actuated and the lock plate 28 attached to the lock base 22 is moved radially outward of the lock base 22, the lock plate 28 is moved within the ratchet hole 30 B of the cover plate 30. It meshes with a ratchet tooth 30C as an engaged portion formed on the periphery. Thus, the rotation of the lock base 22 in the pull-out direction is restricted. As a result, the rotation of the spool 14 connected with the lock base 22 via the connecting member 24 and the torsion shaft in the pull-out direction is limited.

  Further, as shown in FIG. 4, the webbing take-up device 10 includes a torsion shaft (not shown). The torsion shaft is formed in a rod shape, is accommodated in a torsion shaft insertion hole of the spool 14 and is disposed along the axial direction of the spool 14. One end of the torsion shaft is locked to the spool 14, and the other end of the torsion shaft is connected to the lock base 22 by locking to the connecting member 24. Then, when the rotation of the lock base 22 in the pull-out direction is restricted, the intermediate portion in the longitudinal direction of the torsion shaft is torsionally deformed to allow rotation of the webbing in the pull-out direction. It has become. Here, in the present embodiment, an FL stopper mechanism for limiting the amount of torsional deformation of the torsion shaft to a predetermined amount of deformation is provided inside the spool 14. Note that whether or not to provide the FL stopper mechanism may be appropriately selected in consideration of the amount of withdrawal of the webbing from the spool 14 and the like.

  The lock base 22 is formed in a substantially disc shape extending in the radial direction with the axial direction as the thickness direction. On the other axial side of the lock base 22, a plurality of lock base side engagement teeth 22F are provided along the circumferential direction. Further, on one side in the axial direction of the lock base 22, a lock plate disposition concave portion 22I described later is provided.

  The connecting member 24 is formed in a substantially disc shape extending in the radial direction with the axial direction as the thickness direction, and the connecting member 24 is engaged with the lock base 22 in the axial direction. It is possible to rotate with it. Further, the other end of the torsion shaft (not shown) is engaged with the axial center of the connecting member 24. Further, on one axial direction side of the connecting member 24, a plurality of connecting member side engaging teeth 24H corresponding to the lock base side engaging teeth 22F of the lock base 22 are provided. Further, in the state where the lock base 22 and the connection member 24 are engaged, the lock base side engagement teeth 22F and the connection member side engagement teeth 24H are alternately arranged in the circumferential direction and arranged at equal intervals. It is done.

  A rack (not shown) is engaged with the lock base side engagement teeth 22F and the connection member side engagement teeth 24H. The rack is formed in a rod shape using a material (for example, a synthetic resin) softer than the lock base 22 and the connection member 24, and the rack is disposed inside the pipe 46. The rack is configured to move inside the pipe 46 and inside the cover plate 30 (inside the rack accommodating portion 34) by the pressure of gas supplied from a micro gas generator (not shown) when the vehicle is in an emergency.

  Next, the detailed configuration of the lock plate 28 and the lock base 22 will be described.

  As shown in FIGS. 5 and 6, the lock plate 28 is formed in a plate shape with the thickness direction in the axial direction in a state of being supported by the lock base 22 described later, and has a rectangular shape when viewed from the thickness direction Is formed. A lock tooth 28A which engages with a ratchet tooth 30C (see FIG. 3) formed on the inner peripheral portion of the ratchet hole 30B of the cover plate 30 on the other side in the circumferential direction on the tip end side (one end) of the lock plate 28 Is formed. Further, on the tip end side of the lock plate 28, a sensor mechanism engagement convex portion 28B which protrudes toward one side in the axial direction is provided. The sensor mechanism engagement convex portion 28B is engaged with the sensor mechanism 44 (see FIG. 2).

  A support hole 28 </ b> C axially penetrated is formed on the proximal end side (the other end) of the lock plate 28. The support holes 28C are formed in a circular shape when viewed from the axial direction. Further, a part of the outer peripheral surface on the proximal end side of the lock plate 28 and the surface opposite to the lock teeth 28A are formed in a cylindrical surface shape with the hole center of the support hole 28C as the axial center L. In addition, the surface formed in this cylindrical surface shape is called opposing surface 28D. And as shown in FIG. 6, this opposing surface 28D is inclined toward the axial center L side as it goes to one side in the axial direction with respect to the hole center (axial center L) of the support hole 28C. As a result, the other axial end of the facing surface 28D is convex (pointed). The convex portion is called a convex portion 28E.

  As shown in FIG. 7, on one axial side of the lock base 22, there is formed a lock plate disposition concave portion 22I as a lock portion disposition concave portion in which the axial direction one side is opened and the lock plate 28 is disposed. There is. The radially outer side of the lock plate disposition recess 22I is open. Thus, when the lock plate 28 tilts relative to the lock base 22 as described later, the lock teeth 28A of the lock plate 28 project radially outward from the outer peripheral portion of the lock base 22. .

  Further, a cylindrical support shaft 22J as a support shaft portion is erected in the lock plate disposition concave portion 22I toward one side in the axial direction. By inserting the support shaft 22J into a support hole 28C formed in the lock plate 28, the lock plate 28 is tiltably (movably) supported by the lock base 22. When the lock plate 28 is supported by the lock base 22, the opposite surface 28D of the lock plate 28 radially faces and is close to the inner surface 22K of the lock plate disposition recess 22I. The portion of the inner surface 22K of the lock plate disposition concave portion 22I which is radially opposed to the opposing surface 28D of the lock plate 28 is formed in a cylindrical surface shape extending in parallel in the axial direction.

  As shown in FIG. 3 and FIG. 7, a cover plate 48 as a cover member that covers the open end side of the lock plate disposition concave portion 22I is attached to the surface on one side in the axial direction of the lock base 22. By having the cover plate 48, extraction (movement to one side in the axial direction) of the lock plate 28 from the lock plate disposition concave portion 22I is restricted. The cover plate 48 is formed with an insertion hole 48A into which the distal end side of the support shaft 22J is inserted.

(Operation and effect of the present embodiment)
Next, the operation and effects of the present embodiment will be described.

  As shown in FIG. 2, FIG. 3 and FIG. 7, according to the webbing retractor 10 of the present embodiment, when the sensor mechanism 44 is activated at the time of a collision of the vehicle which is one aspect of the emergency of the vehicle, The sensor mechanism 44 moves the sensor mechanism engagement convex portion 28B of the lock plate 28. As a result, the lock plate 28 is tilted with respect to the lock base 22, and the lock teeth 28A of the lock plate 28 mesh with the ratchet teeth 30C formed on the inner peripheral portion of the ratchet hole 30B. Thus, the rotation of the lock base 22 in the pull-out direction (the direction opposite to the arrow C) is restricted. As a result, the rotation of the spool 14 connected via the lock base 22 via the connecting member 24 and the torsion shaft in the pull-out direction is limited.

  As shown in FIG. 4, when a micro gas generator (not shown) is activated at the time of a vehicle collision, high pressure gas generated by the micro gas generator is instantaneously supplied into the pipe 46 in which the rack is disposed. The lock base side engagement teeth 22F of the lock base 22 and the connection member side engagement teeth 24H of the connection member 24 bite into the rack moved by the pressure of the gas. Thereby, kinetic energy of the rack can be transmitted to the lock base 22 and the connection member 24.

  When the rack 38 is moved with the lock base side engagement teeth 22F of the lock base 22 and the connection member side engagement teeth 24H of the connection member 24 biting into the rack 38, the connection member 24 and the lock base 22 are spooled. 14 is rotated in the winding direction (arrow C direction). As a result, the webbing is taken up by the take-up portion 14B of the spool 14, and the restraining force by the webbing is increased.

  In addition, the body of the occupant pulls the webbing in a state in which the rotation of the lock base 22 in the pull-out direction is restricted, and the rotational force of the spool 14 in the pull-out direction based on the tensile force causes the torsion shaft to resist torsion When the load is exceeded, the torsion shaft is twisted (deformed). As a result, the torsion of the torsion shaft allows rotation of the spool 14 in the pull-out direction and allows the webbing to be pulled out of the spool 14. As a result, energy (kinetic energy of the occupant) corresponding to the amount of withdrawal of the webbing from the spool 14 is absorbed by the deformation of the torsion shaft. In the present embodiment, an FL stopper mechanism is provided to limit the amount of torsional deformation of the torsion shaft to a predetermined amount of deformation. Therefore, when the amount of torsional deformation of the torsion shaft reaches a predetermined amount of deformation and the FL stopper mechanism is actuated, the rotation of the spool 14 in the pulling direction permitted by the torsional deformation of the torsion shaft is restricted.

  When a load is input from the webbing to the spool 14 in a state in which the rotation of the spool 14 in the pulling-out direction permitted by the torsional deformation of the torsion shaft is restricted, the support shaft 22J supporting the lock plate 28 is shown in FIG. It is conceivable to deform or break as shown in FIG. In this case, the convex portion 28E in the opposing surface 28D of the lock plate 28 bites into the inner surface 22K of the lock plate disposition concave portion 22I. Thereby, the displacement of the lock plate 28 to one side in the axial direction with respect to the lock base 22 is restricted, and the engagement state between the lock teeth 28A of the lock plate 28 and the ratchet teeth 30C formed on the inner peripheral portion of the ratchet hole 30B is You can keep it.

  Further, by restricting the displacement of the lock plate 28 to one side in the axial direction with respect to the lock base 22, the load applied to the cover plate 48 from the lock plate 28 disposed in the lock plate disposition recess 22I is reduced. Thus, the thickness of the cover plate 48 can be reduced, and the increase in size and weight of the webbing retractor 10 in the axial direction can be suppressed.

  In the present embodiment, an example is described in which the convex portion 28E is formed at the other axial end of the opposing surface 28D by inclining the opposing surface 28D of the lock plate 28. However, the present invention is not limited thereto. It is not limited. For example, as shown in FIG. 10, by projecting only the other axial end of the opposing surface 28D of the lock plate 28, a convex 28E is formed at the other axial end of the opposing surface 28D. You may

  Further, although the example in which the lock plate 28 is supported by the support shaft 22J has been described in the present embodiment, the present invention is not limited to this. For example, even if the lock plate 28 is tiltably supported by the lock base 22 in a state where the opposing surface 28D of the lock plate 28 and the inner surface 22K of the lock plate disposition recess 22I abut each other without providing the support shaft 22J. Good.

  Furthermore, in the present embodiment, the example in which the convex portion 28E is formed at the end on the other side in the axial direction in the facing surface 28D has been described, but the present invention is not limited to this. For example, depending on the manner of support of the lock plate 28 with respect to the lock base 22, the convex portion 28E may be formed at an axial intermediate portion or one end of the opposing surface 28D. Further, depending on the manner of support of the lock plate 28 with respect to the lock base 22, the cover plate 48 may not be provided.

  Further, as shown in FIG. 11, in the case of forming the lock plate 28 by pressing a plate-like material, a shear surface generated on the outer peripheral surface (including the facing surface 28D) of the lock plate 28 by the pressing. The convex portion 28E may be formed on the facing surface 28D of the lock plate 28 using 28F and the fracture surface 28G. The sheared surface 28F is a portion having streak-like linear marks in the thickness direction of the lock plate 28, and the fractured surface 28G is a surface roughness formed by peeling off the material of the lock plate 28. It is the rough part (the part that is rougher and less glossy than the shear surface).

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to the above, and can be variously modified and carried out in addition to the above in the range which does not deviate from the main point. Of course.

10 Webbing retractor 14 Spool 22 Lock base (base part)
22I Lock Plate Placement Recess (Lock Part Placement Recess)
22J Support shaft (support shaft)
28 Lock plate (lock part)
28F Cross section 28G Broken surface 48 Cover plate (cover member)

Claims (6)

A spool which is wound on a webbing to be mounted on a passenger and which is rotated in a pulling direction by pulling out the webbing;
A base portion rotatably provided with the rotation of the spool;
The portion supported by the base portion and engaged with the engaged portion by being moved with respect to the base portion to restrict rotation of the base portion in the pull-out direction, and a portion facing the base portion A lock portion at least a part of which is formed in a convex shape,
Webbing take-up device equipped with   The webbing take-up device according to claim 1, wherein one side of the base portion in the rotation axis direction of the portion facing the base portion in the lock portion is formed in a convex shape.   The webbing take-up device according to claim 2, wherein the base portion is formed with a lock portion disposition concave portion in which the other side in the rotation axis direction of the base portion is opened and the lock portion is disposed.   The webbing take-up device according to claim 3, wherein a cover member that covers an open end side of the lock portion disposition concave portion is attached to the base portion. The base portion is provided with a pivot portion that supports the lock portion in a tiltable manner,
5. The device according to claim 1, wherein in the state where the lock portion is supported by the pivot portion, the convexly formed portion of the lock portion is separated from the base portion. The webbing winding device as described. The lock portion is formed in a plate shape whose thickness direction is the direction of the rotation axis of the base portion.
In the lock portion, the portion on the other side in the rotation axis direction of the base portion facing the base portion is taken as the fracture surface, and the portion on the one side of the rotation axis direction of the base portion is more than the fracture surface. The webbing retractor according to any one of claims 1 to 5, wherein the sheared surface protrudes toward the base portion.