JP3996779B2 - Seat belt retractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lock activation mechanism that reacts to a sudden acceleration change of a vehicle or a rapid webbing pull-out, and an emergency lock mechanism that operates by the lock activation mechanism to prevent rotation of the webbing take-up drum in the pull-out direction; It is related with the retractor for seatbelts which has.
[0002]
[Prior art]
Generally, a seat belt device provided in a seat of a vehicle or the like is configured such that webbing is wound around a retractor provided with an emergency lock mechanism. In the event of a collision, a sudden change in acceleration due to the impact force or a sudden pull-out of the webbing is detected, the lock activation mechanism is activated to activate the emergency lock mechanism, and the winding drum on which the webbing is wound By preventing the rotation of the webbing, the webbing is prevented from being pulled out, and the occupant is restrained and protected.
[0003]
As this type of seat belt retractor, for example, there is one disclosed in Japanese Patent Application Laid-Open No. 11-192923, and a lock base attached to a shaft for winding a webbing so as to be integrally rotatable, and a lock base housed in the lock base. And a lock gear that forms external teeth on the outer periphery and engages the shaft so as to be relatively rotatable and locks the pawl with the internal teeth of the lock base when the rotation is stopped. A first lock activation mechanism comprising: an inertial body that reacts to an acceleration greater than a predetermined value of the vehicle; and a lever that engages with the outer teeth of the lock gear by the inertial body; and a cylindrical inner wall having inner teeth on the inner peripheral surface And a cover fixed to the frame and rotatably supported at a position deviated with respect to the rotation center of the lock gear and separated from the inner teeth of the inner wall Is a structure in which a second locking activation mechanism comprising a normally-biased flywheel direction.
[0004]
The first lock activation mechanism is activated to prevent the rotation of the lock gear when the vehicle suddenly changes in acceleration, and the second lock activation mechanism is activated to activate the lock gear when the webbing is suddenly pulled out. When the rotation of the lock gear is blocked and the rotation of the lock gear is blocked, the pawl engages with the lock base, the rotation of the shaft is blocked, and the webbing withdrawal is stopped.
[0005]
[Problems to be solved by the invention]
In general, when two types of lock activation mechanisms that react to sudden changes in vehicle acceleration or webbing pullout are mounted on a single seatbelt retractor, this increases the number of components and the size of the device itself. There was a problem.
[0006]
In order to solve such a problem, as disclosed in the above-mentioned conventional publication, one end of a cylindrical inner wall having inner teeth formed on the inner peripheral surface thereof is integrally formed so as to be joined to the cover, The diameter of the outer periphery and the cylindrical inner wall is changed, and the arrangement is such that the outer teeth of the lock gear are positioned on the outer peripheral side of the inner wall on the same plane.
[0007]
However, when the flywheel in which inertial delay has occurred with respect to the rotation of the shaft due to the rapid withdrawal of the webbing is engaged with the inner teeth of the inner wall, a load due to the engagement acts on the joint portion between the inner wall and the cover. If the load is large, the inner wall will be deformed or damaged in the centrifugal direction, the flywheel and the inner teeth will be disengaged, and the start of the lock activation mechanism will be delayed, or the lock operation by the lock mechanism will be activated. There is a risk of not.
[0008]
In addition, when such a lock activation mechanism is used for a long time, the flywheel comes into contact with a part of the inner teeth of the inner wall deformed in the centrifugal direction, so that the inner teeth are worn and reduced and the initial shape cannot be maintained, There was a risk that the locking performance would decrease.
[0009]
On the other hand, although it is possible to prevent the inner wall from being deformed in the centrifugal direction by increasing the thickness of the inner wall, there is a problem that the size of the entire retractor is increased.
[0010]
In view of the above problems, an object of the present invention is to provide a seatbelt retractor that is improved in durability without causing an increase in size.
[0011]
[Means for solving the problems]
The technical means for achieving the above-mentioned object is integrated with a housing body having a substantially U-shaped cross section having a pair of opposing side plates each provided with a through hole, and a winding drum on which a webbing is wound. A shaft body that is rotatably connected and is rotatably supported on the side plate as a penetrating shape in the through hole, and is urged to rotate in the webbing take-up direction, and the rotation of the shaft body in the webbing pull-out direction is stopped. An emergency lock mechanism, and first and second lock activation mechanisms for operating the emergency lock mechanism, the emergency lock mechanism including a lock tooth formed on one inner peripheral surface of the through hole of the housing body, and a lock thereof A lock base that is attached to the shaft body so as to be rotatable integrally with the shaft body inside the teeth, and is held by the lock base and protrudes from the outer peripheral surface of the lock base so as to protrude and retract. A pawl engaged with the lock base, and is attached to the shaft body adjacent to the outer surface side of the lock base so as to be rotatable relative to the shaft body, and is attached to the lock base so as to be able to rotate synchronously with being biased in the webbing pull-out direction. A ratchet wheel portion having a ratchet formed on the surface is provided on the outer peripheral portion, and a projecting guide groove for projecting the pawl is formed by sliding an interlocking pin projecting on the pawl by relative rotation with the lock base. A lock clutch body, and the first lock starting mechanism engages with the ratchet of the ratchet wheel portion according to the swing of the inertia mass body and the inertia mass body swinging in response to a rapid acceleration of the vehicle. And a sensor lever for preventing rotation of the lock clutch body, and the second lock starting mechanism includes first and second lock starting mechanisms. A cover body that covers a part, is coupled to the housing body, is disposed inside the ratchet wheel portion, and has a cylindrical engaging inner peripheral wall integrally protruding on the inner peripheral surface thereof; and a cover And is urged in a direction away from the inner teeth of the engagement inner peripheral wall, and is biased in a direction away from the inner teeth of the engagement inner peripheral wall, and is urged in response to a sudden rotation of the lock clutch body. A lock arm that engages with the inner teeth due to a rotation delay in the opposite direction to prevent the lock clutch body from rotating, and the cover body is arranged on the outer side in the axial direction of the winding drum on the cylindrical engagement inner peripheral wall. A side wall portion of the cover body covering the inside of the engagement inner peripheral wall is integrally provided at the edge, and a radially outer peripheral portion of the engagement inner peripheral wall is formed so as to protrude toward the side plate over the entire circumference. It has an inner peripheral wall support A concave groove is provided in an annular shape on the outer surface of the inner peripheral wall support portion, and the upright portion located on the outer peripheral surface side of this groove portion protrudes from the side wall portion of the cover body in the protruding direction in the axial direction. It is in the point formed .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 to 4, the seat belt retractor 1 is formed of an aluminum material or the like around which a webbing as a seat belt is wound. A winding drum 2 is provided, and both end portions in the axial center direction have flange portions 2a formed in a radial direction, and the coupling hole portion 2b formed on one flange portion 2a side includes: A joined body 3 made of steel or the like is press-fitted and fixed so as not to be relatively rotatable.
[0014]
Then, the torsion bar 4 is inserted into the take-up drum 2 and one end thereof is spline-coupled to the press-fitted and bonded assembly 3, where the torsion bar 4 and the take-up drum 2 are at one end. The combined body 3 and the torsion bar 4 are coupled to the take-up drum 2 so as to be rotatable relative to each other. A lock base 5 is splined to the other end of the torsion bar 4 so as to rotate integrally.
[0015]
As shown in FIGS. 5 and 6, the lock base 5 includes a lock base body 5a made of an aluminum material or the like and a resin holding plate 5b attached to one side of the lock base body 5a. A pawl 6 made up of and the like is held from the outer peripheral surface of the lock base 5 so as to be able to appear and retract.
[0016]
Further, the cylindrical portion 5c protruding from one side surface of the lock base main body 5a is fitted into the winding drum 2, and the winding drum is inserted into the circumferential engagement groove 5d formed on the outer peripheral surface of the cylindrical portion 5c. The retaining stopper 7 attached to 2 is locked and retained from the winding drum 2.
[0017]
The winding drum 2 is rotatably supported by the housing body 9, and the housing body 9 is a plane provided with a back plate 9 a fixed to the vehicle body and side plates 9 b extending opposite to each other from both side edges. The winding drum 2 is rotatably supported between both side plates 9b.
[0018]
That is, the coupling body 3 at one end of the shaft body connected and fixed to the winding drum 2 is formed in a through-hole shape in a through hole 9c formed in one side plate 9b so as to be supported rotatably through a support structure. Has been. Further, the other end portion of the torsion bar 4 as the other end portion of the shaft body is disposed so as to protrude through the through hole 9c formed in the other side plate 9b and is formed to protrude from the lock base 5 which is splined. The end portion of the support shaft portion 5e is rotatably supported by a cover body 10 as a holding case attached to the side plate 9b.
[0019]
The one side plate 9b is appropriately equipped with a spiral spring for rotating and biasing the combined body 3 so as to always rotate and bias the winding drum 2 in the winding direction of the webbing. In the present embodiment, the side plate 9b is also provided with a so-called pretensioner mechanism that takes up slack of the webbing by gas pressure or the like in an emergency such as a collision and restricts the movement of the occupant.
[0020]
Further, on the inner peripheral surface of the through hole 9c of the other side plate 9b in which the lock base body 5a is loosely fitted in a penetrating manner, lock teeth 9d with which the pawl 6 is detachably engaged over the entire circumference are formed. The pawl 6 protruding from the outer peripheral surface of the lock base body 5a and the lock teeth 9d are engaged with each other so that the winding drum 2 is prevented from rotating in the webbing pull-out direction.
[0021]
Further, a disc-shaped lock clutch body 12 is supported on the support shaft portion 5e adjacent to the outer surface side of the lock base 5 so as to be relatively rotatable. As shown in FIGS. A cylindrical ratchet wheel portion 12 b having a ratchet 12 a formed on the outer peripheral surface is integrally formed on the outer peripheral portion of the clutch body 12.
[0022]
In addition, a spring receiving portion 12c projects from one side of the lock clutch body 12, and the spring receiving portion 12c is loosely movable in a groove-shaped spring accommodating portion 5f formed in the lock base body 5a. It is fitted. At this time, the spring receiving portion 12c is elastically urged in a predetermined direction by the return spring 13 made of a coil spring accommodated and held in the spring accommodating portion 5f, and the lock clutch body 12 is urged in the webbing pull-out direction. In this state, it is configured to rotate synchronously with the lock base 5.
[0023]
Further, the lock clutch body 12 is formed with a protruding guide groove 12d in which an interlocking pin 6a projectingly provided on the pawl 6 is slidably guided, and the lock base 5 and the lock clutch that resist the urging force of the return spring 13 are formed. The interlocking pin 6a is configured to be slidably guided along the protruding guide groove 12d by relative rotation with the body 12, and the pawl 6 protrudes from the outer peripheral surface of the lock base 5 so as to freely protrude and retract. It is configured as follows.
[0024]
The lock base 5, the pawl 6, the lock teeth 9d, the lock clutch body 12, and the like constitute an emergency lock mechanism.
[0025]
Further, in order to operate this emergency lock mechanism, a first lock activation mechanism that is activated in response to a sudden change in the acceleration of the vehicle and a first activation mechanism that is activated in response to an abrupt withdrawal of the webbing are provided in the cover body 10. And a two-lock activation mechanism.
[0026]
As shown in FIG. 9, the first lock starting mechanism includes a holder 15 made of a box-shaped resin molded body having a conical concave portion that is open on the top surface and gradually decreases in diameter on the bottom surface. A spherical sensor weight 16 made of steel as an inertial mass that swings in response to an acceleration exceeding a predetermined value and can be rotated at one end of the holder 15. And a sensor lever 17 made of a resin molded body supported by the.
[0027]
In a state where no acceleration exceeding a predetermined value is generated, the sensor weight 16 is maintained in the repose posture disposed on the concave portion of the holder 15, and the lock claw 17 a protruding from the tip of the sensor lever 17 is provided. And the ratchet 12a are kept separated from each other.
[0028]
In this case, the rotation of the lock clutch body 12 is not restricted at all, and therefore the webbing is maintained in a drawable state.
[0029]
On the other hand, when a sudden acceleration change in an emergency such as a vehicle collision or sudden braking occurs, the sensor weight 16 swings and moves from the concave portion in response to the acceleration change. As the weight 16 moves, the sensor lever 17 is pushed upward by the sensor weight 16, and the lock claw 17a of the sensor lever 17 is rotated upward.
[0030]
When the lock claw 17a is engaged with the ratchet 12a of the ratchet wheel portion 12b by this upward rotation, the rotation of the lock clutch body 12 is stopped. Therefore, if a load in the pulling direction acts on the webbing, the return spring 13 is attached. The lock base body 5a rotates in the pulling-out direction of the webbing against the force.
[0031]
As the lock base body 5a rotates, the interlocking pin 6a of the pawl 6 held by the lock base body 5a slides in the protruding guide groove 12d. With this sliding movement, the pawl 6 is projected and moved radially outward from the lock base body 5a, meshes with the lock teeth 9d formed on the side plate 9b of the housing body 9, and the rotation of the lock base body 5a thereafter. Is prevented, the webbing withdrawal is stopped, and the emergency locking mechanism is activated here.
[0032]
When the sudden acceleration change is released, the sensor weight 16 is returned to the concave portion that is the original rest position of the holder 15 by the gravitational action, and the sensor lever 17 is also rotated downward. To return to the initial position.
[0033]
On the other hand, since the load in the pulling direction acting on the webbing is also released, the lock base body 5a is rotated relative to the lock clutch body 12 by the urging force of the return spring 13 and the like, and this rotation causes the interlock in the protruding guide groove 12d. The pin 6a is returned to the initial position, where the pawl 6 is returned to the buried state, and the engagement between the pawl 6 and the lock teeth 9d is released. Then, the webbing is returned to the initial state where the webbing can be pulled out and taken up.
[0034]
The second lock starting mechanism is integrally provided on the inner surface side of the cover body 10 and swings on the inner peripheral surface of the lock arm 19 that is swingably supported by the lock clutch body 12 at the eccentric position. And a cylindrical engagement inner peripheral wall 21 formed with inner teeth 21a with which the distal end locking portion 19a of the lock arm 19 is detachably engaged. That is, as shown in FIGS. 2 to 4, the side wall portion 10 e of the cover body 10 covering the inner side of the engagement inner peripheral wall 21 at the outer edge in the axial direction of the winding drum 2 in the cylindrical engagement inner peripheral wall 21. It is set as the structure equipped with.
[0035]
At this time, the outer diameter of the engagement inner peripheral wall 21 is formed to be slightly smaller than the inner diameter of the ratchet wheel portion 12b, and as shown in FIGS. 1, 2, and 7, the inner diameter of the engagement inner peripheral wall 21 is set inside the ratchet wheel portion 12b. The engaging inner peripheral wall 21 is structured to be loosely fitted.
[0036]
In addition, these cover body 10, the lock clutch body 12, and the lock arm 19 are comprised by the resin molding in this embodiment.
[0037]
Further, the lock clutch body 12 is provided with a swing stopper 12e for restricting the swing range of the lock arm 19, and a release biasing spring 22 made of a coil spring or the like is provided between the lock clutch body 12 and the base portion of the lock arm 19. The lock arm 19 is elastically biased in the disengagement direction.
[0038]
Normally, when the torsion bar 4 and the lock base 5 are rotated in accordance with the rotation of the winding drum 2 by pulling out the webbing, the lock clutch body 12 is synchronously rotated under the resilient force of the return spring 13.
[0039]
When the webbing is taken up, the lock clutch body 12 is synchronously rotated by the pushing of the return spring 13 when the lock base 5 rotates.
[0040]
On the other hand, when the webbing is suddenly pulled out, the rotation of the lock arm 19 does not follow during the synchronous rotation of the lock clutch body 12, and the inertia in the rearward direction of the rotation against the urging force of the release urging spring 22 occurs. A delay occurs, the lock arm 19 is swung in the engagement direction, the tip locking portion 19a protrudes radially outward and engages with the inner teeth 21a of the engagement inner peripheral wall 21, and the lock clutch body 12 Synchronous rotation is prevented.
[0041]
When the lock clutch body 12 stops, the interlocking pin 6a slides in the protruding guide groove 12d as the lock base 5 rotates. With this sliding movement, the pawl 6 is projected and moved radially outward from the lock base body 5a, meshes with the lock teeth 9d formed on the side plate 9b of the housing body 9, and the rotation of the lock base body 5a thereafter. Is prevented, the webbing withdrawal is stopped, and the emergency locking mechanism is activated here.
[0042]
When the webbing is suddenly pulled out, the urging force of the release urging spring 22 returns the lock arm 19 to the initial release position, and the engagement state between the tip engagement portion 19a and the internal teeth 21a is released. Is done. Further, the lock clutch body 12 is rotated relative to the lock base 5 by the urging force of the return spring 13, and this rotation returns the interlocking pin 6a in the protruding guide groove 12d to the initial position. And the meshing between the pawl 6 and the lock teeth 9d is released. Then, the webbing is returned to the initial state where the webbing can be pulled out and taken up.
[0043]
Further, as shown in FIG. 1 to FIG. 4 and FIG. 9, the radially outer peripheral portion of the engaging inner peripheral wall 21 in the cover body 10 protrudes toward the side plate 9b to which the cover body 10 is attached over the entire circumference. The inner peripheral wall support portion 10a is formed, and in the present embodiment, a concave groove portion 10b is annularly provided on the outer surface of the inner peripheral wall support portion 10a. That is, as shown in FIG. 2 and the like, the structure is such that the standing portion 10d is formed on the outer surface side of the outer peripheral wall 10c of the cover body 10 while being positioned on the outer peripheral surface side of the groove portion 10b. At this time, the upright portion 10 d has a structure in which a protruding length in the axial direction of the winding drum 2 protrudes from the side wall portion 10 e of the cover body 10.
[0044]
The present embodiment is configured as described above. When the distal end locking portion 19a of the lock arm 19 is engaged with the inner teeth 21a of the engagement inner peripheral wall 21 by the activation of the second lock activation mechanism, the engagement is performed. Until the pawl 6 is engaged with the lock teeth 9d and the rotation of the shaft body, that is, the winding drum 2, is stopped, the cylindrical engagement inner peripheral wall 21 is moved in the centrifugal direction via the inner teeth 21a. Load acts. The load becomes more rapid as the change in the acceleration of the vehicle due to the pulling out of the webbing, that is, the collision is larger, and the larger load acts.
[0045]
At this time, in this embodiment, since the inner peripheral wall support portion 10a is formed on the outer peripheral portion of the engagement inner peripheral wall 21 so as to protrude toward the free end side of the engagement inner peripheral wall 21, the engagement inner peripheral wall is provided. The load acting on 21 is not received at one end on the base side of the engaging inner peripheral wall 21 as in the prior art, but is received at the intermediate portion in the longitudinal direction of the outer surface of the engaging inner peripheral wall 21, thereby improving durability. I can plan.
[0046]
Therefore, even when the lock arm 19 engages with the inner teeth 21a and a large load in the centrifugal direction acts on the engagement inner peripheral wall 21, the strength of the engagement inner peripheral wall 21 is supported by the support action of the inner peripheral wall support portion 10a. Improvement can be achieved, and breakage can be effectively suppressed to achieve more stable locking performance.
[0047]
Moreover, since the deformation | transformation to the centrifugal direction of the engagement inner peripheral wall 21 can be suppressed effectively, the lock arm 19 and the internal tooth 21a can be meshed | engaged effectively in the whole surface of a tooth | gear, and the initial shape of the internal tooth 21a Can be maintained, and durability can be improved.
[0048]
Therefore, since it is not necessary to enlarge the cover body 10 or increase the thickness of the engagement inner peripheral wall 21, a structure of the engagement inner peripheral wall 21 having high strength can be provided without causing an increase in size.
[0049]
Further, since the groove portion 10b is provided on the outer surface of the inner peripheral wall support portion 10a, not only the weight of the member can be reduced, but also the standing portion on the outer surface side of the outer peripheral wall 10c of the cover body 10 as shown in FIG. When an impact force is applied to the standing portion 10d from the outside, the standing portion 10d can be deformed to the groove portion 10b side to absorb the impact force. Accordingly, there is an advantage that damage and scattering of members can be effectively prevented by the impact force absorbing action at the time of transportation or dropping in the assembled state in which the cover body 10 is fixed to the housing body 9.
[0050]
【The invention's effect】
As described above, according to the seatbelt retractor of the present invention, the first and second lock activation mechanisms that operate the emergency lock mechanism are provided, and the housing body is covered with the first and second lock activation mechanisms. The cover body to be coupled is integrally provided with the side wall portion of the cover body covering the inside of the engagement inner peripheral wall at the outer edge in the axial direction of the take-up drum on the cylindrical engagement inner peripheral wall. radial outer periphery, over the entire circumference, provided with a peripheral wall supporting portion in which is raised formed toward the side plate direction of the housing body is provided with a recessed groove annularly on the outer surface of the inner peripheral wall support, this The upright portion located on the outer peripheral surface side of the groove portion is formed such that the protruding length in the axially outward direction protrudes from the side wall portion of the cover body , and the inner peripheral wall support portion effectively engages the inner peripheral wall. Can be reinforced and has deformation and damage To prevent be exhibited stable locking performance, without increasing the size, there is an advantage that can be improved durability.
[0051]
In addition, a concave groove is provided on the outer surface of the inner peripheral wall support portion in an annular shape, and when an impact force is applied to the standing portion located on the outer peripheral surface side of this groove portion , the rising portion is deformed to the groove portion side. The impact force can be absorbed, and there is an advantage that the impact force absorbing action can be effectively exhibited during transportation in the assembled state or when dropped, and breakage and scattering of members can be effectively prevented.
[Brief description of the drawings]
FIG. 1 is a partial sectional front view showing an embodiment of the present invention.
FIG. 2 is an enlarged view of the same part.
FIG. 3 is a partial cross-sectional side view in FIG. 1;
FIG. 4 is an exploded perspective view of a main part.
FIG. 5 is an exploded perspective view of a lock base portion.
FIG. 6 is a front view of the lock base.
FIG. 7 is a front view of the lock clutch body.
FIG. 8 is a right side view of the same.
FIG. 9 is an explanatory diagram of a first lock starting mechanism portion.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Seatbelt retractor 2 Winding drum 3 Combined body 4 Torsion bar 5 Lock base 6 Pawl 9 Housing body 9c Through hole 9d Lock tooth 10 Cover body 10a Inner peripheral wall support part 10b Groove part 12 Lock clutch body 12a Ratchet 12b Ratchet wheel part 12d Projection guide groove 13 Return spring 15 Holder 16 Sensor weight 17 Sensor lever 19 Lock arm 21 Engagement inner peripheral wall 21a Internal tooth 22 Release bias spring

Claims (1)

A housing body having a substantially U-shaped cross section having a pair of opposing side plates each provided with a through hole, and a winding drum on which a webbing is wound, are connected to be integrally rotatable and penetrate through the through hole. A shaft body rotatably supported on the side plate as a shape, and urged to rotate in the webbing take-up direction, an emergency lock mechanism for stopping the rotation of the shaft body in the webbing pull-out direction, and a first actuating the emergency lock mechanism 1 and a second lock activation mechanism,
The emergency lock mechanism is held by a lock tooth formed on an inner peripheral surface of one through hole of the housing body, a lock base attached to the shaft body so as to be rotatable integrally with the shaft body, and the lock base. And a pawl that protrudes and retracts from the outer peripheral surface of the lock base and meshes with the lock teeth, and is attached to the shaft body adjacent to the outer surface side of the lock base so as to be relatively rotatable and attached in the webbing pull-out direction. It is attached to the lock base so as to be able to rotate synchronously, and has a ratchet wheel portion with a ratchet formed on the outer peripheral surface on the outer peripheral portion, and the interlocking pin protruding from the pawl by the relative rotation with the lock base slides. A lock clutch body formed with a protruding guide groove that is guided by movement to project the pawl,
The first lock starting mechanism is an inertia mass body that swings in response to a rapid acceleration of the vehicle, and engages with the ratchet of the ratchet wheel portion according to the swing of the inertia mass body to rotate the lock clutch body. With a sensor lever to block,
The second lock starting mechanism covers a part of the first and second lock starting mechanisms, is coupled to the housing body, is disposed inside the ratchet wheel portion, and has a cylindrical shape having inner teeth on an inner peripheral surface thereof. And a cover body formed integrally with the engagement inner peripheral wall, and rotatably supported on one side of the lock clutch body facing the cover body, and urged away from the inner teeth of the engagement inner peripheral wall. A lock arm that engages with an internal tooth due to a rotation delay in a direction opposite to the biased direction due to a sudden rotation of the lock clutch body, and prevents rotation of the lock clutch body,
The cover body is integrally provided with a side wall portion of the cover body that covers the inside of the engagement inner peripheral wall at an outer edge of the cylindrical engagement inner peripheral wall in the axial direction of the winding drum. The radially outer peripheral portion includes an inner peripheral wall support portion formed so as to protrude toward the side plate direction over the entire circumferential direction, and a concave groove portion is annularly provided on the outer surface of the inner peripheral wall support portion. The seat belt retractor characterized in that the upright portion located on the outer peripheral surface side is formed such that a protruding length in the outer side in the axial direction protrudes from the side wall portion of the cover body .

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