JP2017100619A - Seatbelt retractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seatbelt retractor which suppresses noise from the vicinity of an acceleration sensor accompanied by the traveling of a vehicle, can release an operation state of a lock cancel mechanism in a short time while eliminating an incongruity imparted to an occupant, and can surely operate the acceleration sensor.SOLUTION: A lock cancel mechanism 70 comprises: a friction lever 72 which is connected to a center hub 71 integrally rotating together with a spindle 10 so as to be rotatable by a friction force, and in which a drive gear 79 is arranged; and a switch lever 90 having an acceleration sensor lock cancel part 94 which inhibits the engagement of the acceleration sensor lever 103 and a tooth part 34 of a steering wheel 30. When the spindle 10 rotates to a winding direction of a seatbelt, the acceleration sensor lock cancel part 94 inhibits a lock operation of an acceleration sensor 100, and when the spindle 10 rotates to a drawl direction of the seatbelt, permits the lock operation of the acceleration sensor 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a seat belt retractor, and more particularly, to a seat belt retractor including an acceleration sensor that detects acceleration in a horizontal direction and locks a pull-out operation of the seat belt.

  A seatbelt device mounted on a vehicle restrains an occupant seated on a seat by a seatbelt pulled out from a seatbelt retractor to protect the occupant in a vehicle collision or the like. The seatbelt retractor detects the acceleration with an acceleration sensor and activates the seatbelt locking mechanism when an acceleration greater than a predetermined value is applied in the horizontal direction during a vehicle collision, etc., thereby making it impossible to pull out the seatbelt. To do.

  Specifically, when the acceleration sensor detects a sudden deceleration state of the vehicle, the acceleration sensor lever of the acceleration sensor locks the steering wheel that is rotatably supported by the spindle, and the steering wheel is delayed in rotation with respect to the spindle. Arise. As a result, the lock member disposed between the spindle and the steering wheel is operated and engaged with the frame to lock the spindle.

  In the conventional acceleration sensor, when the seat belt is worn, the acceleration sensor lever is always kept in a free state, and when an emergency state occurs in the vehicle, it can be immediately locked on the steering wheel. For this reason, as the vehicle travels, the related parts of the acceleration sensor vibrate and noise is generated from the vicinity of the acceleration sensor, which may cause discomfort to the passenger.

  As a seat belt retractor provided with an acceleration sensor, there is disclosed a seat belt retractor provided with a lock canceling mechanism that allows or prevents the operation of the acceleration sensor in conjunction with the withdrawal and winding of the seat belt (for example, see Patent Document 1). ). The seat belt retractor described in Patent Document 1 includes a blocking arm that swings while being frictionally connected to a spool by the elastic force of a spring. When the lock canceling mechanism is activated, the tip of the blocking arm contacts the acceleration sensor lever. The operation of the acceleration sensor is blocked by contact.

International Patent No. 97/02966

  In the lock cancellation mechanism described in Patent Document 1, the tip of the blocking arm abuts against the acceleration sensor lever to prevent the operation of the acceleration sensor lever. This can be prevented while it is in contact with the acceleration sensor lever. However, in order to release the operation state of the lock cancellation mechanism, the tip of the blocking arm must move to a position retracted from the operation area of the acceleration sensor lever. In Patent Document 1, there is a problem that the amount of seat belt withdrawn necessary to release the lock cancellation mechanism increases, and it takes time to release the lock cancellation mechanism.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress the noise from the vicinity of the acceleration sensor that accompanies traveling of the vehicle and eliminate the discomfort given to the occupant while operating the lock cancellation mechanism. An object of the present invention is to provide a seat belt retractor capable of releasing a state in a short time and enabling an acceleration sensor to operate reliably.

The above object of the present invention can be achieved by the following constitution.
(1) a spindle that is rotatably supported by a frame and on which a webbing is wound;
A locking member that locks rotation of the spindle in the webbing pull-out direction by engaging with the frame;
A steering wheel that is rotatably supported by the spindle and that operates the lock member by causing a rotation delay with respect to the spindle;
An acceleration sensor lever that is engageable with a tooth portion formed on the outer peripheral surface of the steering wheel, detects an acceleration in a horizontal direction, and locks the pulling-out operation of the webbing;
A lock cancellation mechanism for blocking the lock operation of the acceleration sensor;
The lock cancellation mechanism comprises
A friction lever fitted with a center hub that rotates integrally with the spindle, and connected to the center hub so as to rotate integrally with a frictional force, and provided with a drive gear;
A driven gear that is rotatably supported by a bearing plate fixed to the frame and meshes with the drive gear of the friction lever, and an acceleration sensor lock that prevents engagement between the acceleration sensor lever and a tooth portion of the steering wheel. A switch lever having a cancellation part;
With
When the spindle rotates in the winding direction of the webbing, the acceleration sensor lock canceling unit prevents the locking operation of the acceleration sensor, and when the spindle rotates in the drawing direction of the webbing, A seat belt retractor characterized by allowing a locking operation.
(2) The seat belt retractor according to (1), wherein the lock canceling mechanism includes a biasing member that biases the switch lever in a direction that prevents the locking operation of the acceleration sensor.
(3) The friction lever is fitted to the center hub, and is connected to the center hub so as to be integrally rotatable with a frictional force. The base is extended radially outward from the base and is driven on the outer peripheral surface. The seat belt retractor according to (1) or (2), further comprising: an arm portion provided with a gear.
(4) The seat belt retractor according to (1) or (2), wherein a pitch circle diameter of the drive gear of the friction lever is larger than a pitch circle diameter of the driven gear of the switch lever.
(5) The seat according to (1), wherein the frictional force between the center hub and the friction lever is applied by a clamp spring that urges the friction lever in a direction to reduce the diameter of the base. Belt retractor.
(6) The seat according to (1), wherein any one of the bearing plate and the cover member facing the bearing plate includes a swing limiting member that limits a swing range of the friction lever. Belt retractor.

  According to the seat belt retractor of the present invention, the lock cancel mechanism for preventing the lock operation of the acceleration sensor is coupled to the center hub that rotates integrally with the spindle so as to be integrally rotatable by frictional force, and the friction lever provided with the drive gear. A driven gear that meshes with the drive gear of the friction lever, and a switch lever having an acceleration sensor lock canceling portion that prevents engagement between the acceleration sensor lever and the tooth portion of the steering wheel. When the spindle rotates in the seat belt take-up direction, the acceleration sensor lock canceling unit prevents the acceleration sensor from being locked, and when the spindle rotates in the seat belt withdrawal direction, the acceleration sensor lock operation is allowed. . As a result, noise from the vicinity of the acceleration sensor associated with vehicle travel can be suppressed and the discomfort given to the occupant can be eliminated, and the operating state of the lock cancellation mechanism can be released in a short time, and the acceleration sensor can be operated reliably. be able to.

It is a disassembled perspective view of the seatbelt retractor of one Embodiment of this invention. It is sectional drawing of the seatbelt retractor shown in FIG. It is a side view which shows a lock cancellation mechanism by removing a cover member. (A) is sectional drawing which shows the fitting state of a center hub and a friction lever, (b) is a side view which shows the state which the clamp spring fitted to the base of the friction lever. It is a perspective view of the acceleration sensor lever which comprises an acceleration sensor. FIG. 6 is a side view showing a state in which the seat belt is pulled out, the switch lever is swung clockwise, and the lock cancellation mechanism is inoperative, with the cover member removed. FIG. 7 is a side view showing a state where the seat belt is wound from the state shown in FIG. 6 and the switch lever swings counterclockwise and the lock canceling mechanism is operating, with the cover member removed. FIG. 6 is a side view showing a state where the seat belt is pulled out when the vehicle suddenly decelerates and the lock cancellation mechanism becomes inoperative, and the acceleration sensor lever of the acceleration sensor engages with the tooth portion of the steering wheel with the cover member removed. .

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a seat belt retractor according to the present invention will be described in detail with reference to the drawings.

  As shown in FIGS. 1 and 2, the seat belt retractor 1 is accommodated in a metal spindle 10 (for example, aluminum alloy) around which a seat belt (not shown) as webbing is wound, and a cover 12. A spring-type winding device 11 that urges the spindle 10 to rotate in the winding direction, a metal U-shaped frame 13 that rotatably supports the spindle 10, and a metal (for example, iron) that serves as a locking member. ) Lock dock 20, resin steering wheel 30, bearing plate 60 fixed to the frame 13, acceleration sensor 100 for sensing the acceleration of the vehicle body, and lock canceling mechanism 70 for preventing the acceleration sensor 100 from locking. And a cover member 15 fixed to the frame 13 so as to cover the bearing plate 60. .

  The frame 13 has left and right side plates 13A and 13B facing each other across the central portion of the spindle 10 in the axial direction. The emergency lock mechanism, the acceleration sensor 100, and the lock cancellation mechanism 70 are disposed outside the one side plate 13A. The winding device 11 is disposed outside the side plate 13B. The shaft 14 on one end side of the spindle 10 passes through the steering wheel 30 and the bearing plate 60, and a center hub 71 is fitted to the tip thereof so as to rotate integrally.

  On the inner periphery of the circular opening of the side plate 13 </ b> A of the frame 13, a number of internal teeth 17 that can be engaged with the claws 22 of the lock dock 20 are formed. The lock dock 20 is slidably accommodated in a space secured between one end face of the spindle 10 and a metal (for example, iron) safety plate 25 fixed to the end face. Is held in the unlocking direction away from the internal teeth 17 of the frame 13. The lock dock 20 includes a cam pin 21 that is inserted into a cam hole 31 formed in the steering wheel 30.

  The steering wheel 30 is supported by the spindle 10 so as to be relatively rotatable, and has a cam hole 31 with which the cam pin 21 of the lock dock 20 is engaged, and a tooth portion 34 formed on the outer peripheral surface.

  The cam hole 31 pushes the claw 22 of the lock dock 20 outward through the cam pin 21 when the steering wheel 30 rotates relative to the spindle 10. For example, when the steering wheel 30 is delayed with respect to the spindle 10 when the seat belt is pulled out, the lock dock 20 is operated to the lock side by the relative rotation of the spindle 10 and the steering wheel 30. Then, the claw 22 jumping out is engaged with the internal teeth 17 of the frame 13 to lock the spindle 10 to the internal teeth 17 of the frame 13 and mechanically lock the rotation in the seat belt pull-out direction.

  3 and 4, the lock cancellation mechanism 70 includes a friction lever 72 and a switch lever 90. The friction lever 72 is integrally formed with a base portion 74 fitted on the center hub 71 and an arm portion 75 extending radially outward from the base portion 74.

  The base 74 is formed in a substantially C shape in which a part in the circumferential direction is cut out in a side view, and a cutout groove 76 extending in the radial direction is provided on the opposite side of the cutout. Thereby, the base 74 can be elastically deformed (reduced diameter) in the radial direction.

  The inner peripheral surface of the base portion 74 is formed in a substantially semicircular cross section, and is slidably fitted in an annular groove 77 of the center hub 71. An annular groove 78 into which the clamp spring 73 is fitted is provided on the outer peripheral surface of the base 74. A female spline 80 is formed at the center of the center hub 71 and is spline-fitted to the shaft 14 on one end side of the spindle 10 to rotate integrally with the spindle 10.

  The base 74 is fitted into an annular groove 77 of the center hub 71, and a clamp spring 73 is attached to an annular groove 78 formed on the outer peripheral surface. Accordingly, the diameter of the base portion 74 is reduced by the elastic force of the clamp spring 73, and the center hub 71 and the base portion 74 are coupled by the frictional force. The magnitude of the frictional force is substantially proportional to the elastic force of the clamp spring 73.

  As a result, when the center hub 71 rotates together with the spindle 10, the friction lever 72 can rotate integrally by the frictional force between the center hub 71 and the base 74. More specifically, when the transmission torque is smaller than the torque due to the frictional force between the center hub 71 and the base 74, the center hub 71 and the base 74 rotate together. Further, when the transmission torque is larger than the torque due to the frictional force between the center hub 71 and the base 74, the center hub 71 and the base 74 slide relative to the frictional force and rotate relative to each other. Further, a substantially fan-shaped drive gear 79 is provided on the outer peripheral surface of the arm portion 75 of the friction lever 72.

The friction lever 72 is disposed between a pair of protrusions 61 and 62 provided with an arm 75 protruding from the bearing plate 60, and the swing range thereof is limited by the pair of protrusions (swing limit members) 61 and 62. Has been.
In addition, as long as the swinging range of the friction lever 72 can be limited, it is not limited to the pair of protrusions 61 and 62 and may be provided on the cover member 15.

  The switch lever 90 includes a substantially triangular plate-shaped main body 91 and a driven gear 92 integrally formed on a side surface of the main body 91, and a support hole 93 formed at the rotation center of the driven gear 92 includes a bearing plate. The support shaft 63 is provided so as to project from the shaft 60 and is rotatably supported.

  An acceleration sensor lock canceling portion 94 is provided at the tip of the main body 91 and is disposed to face an acceleration sensor lever 103 of an acceleration sensor 100 described later. The driven gear 92 meshes with the drive gear 79 of the friction lever 72.

  The pitch circle diameter DA of the drive gear 79 of the friction lever 72 is set to be larger than the pitch circle diameter DB of the driven gear 92 of the switch lever 90, for example, twice or more. Thereby, the swinging rotation of the friction lever 72 is greatly amplified and rotationally drives the switch lever 90. That is, the slight swing of the friction lever 72 is increased in speed and causes the switch lever 90 to rotate greatly.

  A coil spring 95 that is an urging member is attached to the switch lever 90 between the spring support pin 64 of the bearing plate 60. The switch lever 90 is biased in a direction (counterclockwise in FIG. 3) in which the acceleration sensor lock canceling portion 94 approaches the acceleration sensor lever 103 of the acceleration sensor 100 by the elastic force of the coil spring 95.

  The elastic force of the coil spring 95 is set to be smaller than the frictional force between the center hub 71 and the friction lever 72 (base 74). That is, the elastic force of the coil spring 95 can absorb the backlash between the drive gear 79 and the driven gear 92 by urging the switch lever 90 in one direction, but the friction lever 72 (base portion) resists the frictional force. 74) does not rotate relative to the center hub 71.

  The acceleration sensor 100 includes a sensor holder 101 disposed between the bearing plate 60 and the cover member 15, an inertial body (ball) 102 that is stored in the sensor holder 101 and is displaced according to the acceleration in the horizontal direction, and a shaft An acceleration sensor lever 103 which is rotatably arranged by a support shaft 106 inserted into the hole 105 and whose tip tooth tip 104 approaches and separates from a tooth portion 34 formed on the outer peripheral surface of the steering wheel 30. .

  As shown in FIG. 5, the acceleration sensor lever 103 has a locking piece 107 extending in the lateral direction from a tip tooth tip 104 provided on the side opposite to the shaft hole 105. An acceleration sensor lock canceling portion 94 of the switch lever 90 is disposed facing the locking piece 107.

  When the ball 102 moves in accordance with the vehicle body acceleration, the acceleration sensor lever 103 swings and the tip tooth tip 104 engages with the tooth portion 34 of the steering wheel 30 to lock the steering wheel 30.

Next, the operation of the lock cancellation mechanism 70 will be described with reference to FIGS.
As shown in FIG. 6, when the seat belt is pulled out of the seat belt retractor 1 for mounting, the center hub 71 rotates counterclockwise together with the spindle 10. Along with this, the friction lever 72 coupled to the center hub 71 by the frictional force of the elastic force of the clamp spring 73 rotates counterclockwise until the arm portion 75 comes into contact with one protrusion 62 of the bearing plate 60.

  After the arm portion 75 comes into contact with the protrusion 62, only the center hub 71 (spindle 10) can rotate against the frictional force between the center hub 71 and the friction lever 72, thereby obstructing the withdrawal of the seat belt. There is no.

  As the friction lever 72 swings, the switch lever 90 that engages the driven gear 92 with the drive gear 79 rotates clockwise around the support shaft 63 of the bearing plate 60 against the elastic force of the coil spring 95. Is done.

  As a result, the acceleration sensor lock cancellation unit 94 of the switch lever 90 moves away from the acceleration sensor lever 103 of the acceleration sensor 100 and moves to a non-operating position that permits the locking operation of the acceleration sensor lever 103, so that the lock cancellation mechanism 70 is moved. It becomes inactive.

  In this state, when a horizontal acceleration larger than a predetermined value acts on the acceleration sensor 100, the ball 102 moves, the acceleration sensor lever 103 swings clockwise in FIG. 6, and the tip tooth tip 104 moves to the steering wheel. 30 teeth 34 can be engaged, and the acceleration sensor 100 is in an operable state.

  Next, as shown in FIG. 7, after the seat belt tongue pulled out from the seat belt retractor 1 is inserted into a buckle (none of which is shown), the spring force of the winding device 11 is used to remove the slack of the seat belt. Thus, the spindle 10 is rotated in the clockwise direction, and the seat belt is attached while the seat belt is retracted.

  The friction lever 72 coupled to the center hub 71 that rotates together with the spindle 10 by a frictional force rotates clockwise until the arm portion 75 contacts the other protrusion 61 of the bearing plate 60.

  If the seat belt is still slack after the arm 75 and the other protrusion 61 abut, the center hub 71 (spindle 10) resists the frictional force with the friction lever 72 by the spring force of the winding device 11. Rotate to eliminate slack and restrain the occupant.

  As the spindle 10 rotates in the clockwise direction, the switch lever 90 in which the driven gear 92 meshes with the drive gear 79 is driven to rotate counterclockwise about the support shaft 63. As a result, the acceleration sensor lock canceling portion 94 of the switch lever 90 abuts on the locking piece 107 extending in the lateral direction from the acceleration sensor lever 103 of the acceleration sensor 100 to block the locking operation of the acceleration sensor 100. That is, the lock cancellation mechanism 70 is activated.

  As described above, when the seat belt is worn, the acceleration sensor lever 103 of the acceleration sensor 100 abuts against the acceleration sensor lock canceling portion 94 of the switch lever 90 and restrains the movement of each component of the acceleration sensor 100. Generation of noise from the sensor 100 is prevented, and the passenger is not uncomfortable.

  Further, when the arm portion 75 comes into contact with the other protrusion 61, torque transmitted from the friction lever 72 to the switch lever 90 is lost, so that the switch lever 90 is moved by the backlash between the drive gear 79 and the driven gear 92. There is a possibility that noise can be generated because it can freely rotate. However, since the switch lever 90 is always urged counterclockwise by the elastic force of the coil spring 95 and restrains the movement of the acceleration sensor lever 103, no noise is generated.

  In the seat belt wearing state shown in FIG. 7, when the vehicle suddenly decelerates, the occupant also moves forward, and the seat belt is pulled out slightly, and the spindle 10 rotates counterclockwise as shown in FIG. The rotation of the spindle 10 causes the friction lever 72 connected to the center hub 71 to rotate counterclockwise via a frictional force.

  As a result, the switch lever 90 in which the driven gear 92 meshes with the drive gear 79 of the friction lever 72 rotates in the clockwise direction, and the acceleration sensor lock canceling portion 94 is separated from the acceleration sensor lever 103 of the acceleration sensor 100, and the acceleration sensor. The lever 103 is moved to a position that allows the operation of the lever 103. That is, the lock cancellation mechanism 70 is switched from the operating state to the non-operating state.

  Although the rotation angle of the spindle 10 (friction lever 72) by pulling out the seat belt during sudden deceleration of the vehicle is slight, the pitch circle diameter DA of the drive gear 79 of the friction lever 72 is the pitch circle of the driven gear 92 of the switch lever 90. Since it is set to be larger than the diameter DB, when the friction lever 72 slightly swings and rotates, the switch lever 90 is increased in speed and rotates greatly, and the lock canceling mechanism 70 is deactivated.

  On the other hand, in the acceleration sensor 100, when the ball 102 moves, the acceleration sensor lever 103 swings and the tip tooth tip 104 engages with the tooth portion 34 of the steering wheel 30 to lock the steering wheel 30. Then, a rotation delay occurs in the steering wheel 30 relative to the spindle 10, the relative rotation of the spindle 10 and the steering wheel 30 activates the lock dock 20 to the lock side, and the pawl 22 is locked to the internal teeth 17 of the frame 13. Lock the seat belt drawer to protect the passengers safely.

  According to the seat belt retractor 1 of the present embodiment, the lock cancellation mechanism 70 that prevents the acceleration sensor 100 from being locked is connected to the center hub 71 that rotates integrally with the spindle 10 so as to be integrally rotatable by frictional force, and the drive gear 79. A friction lever 72, a driven gear 92 that meshes with the drive gear 79 of the friction lever 72, and an acceleration sensor lock canceling portion 94 that prevents the acceleration sensor lever 103 and the tooth portion 34 of the steering wheel 30 from engaging with each other. And a switch lever 90 having the same.

  When the spindle 10 rotates in the seat belt retracting direction, the acceleration sensor lock canceling unit 94 prevents the acceleration sensor 100 from locking, and when the spindle 10 rotates in the seat belt retracting direction, the acceleration sensor 100 cancels. Allow lock operation. Therefore, it is possible to release the operation state of the lock cancel mechanism 70 in a short time while suppressing noise from the vicinity of the acceleration sensor accompanying traveling of the vehicle and eliminating discomfort given to the occupant, and to enable the acceleration sensor 100 to operate reliably. can do

  The lock cancel mechanism 70 includes a coil spring 95 that biases the switch lever 90 in a direction in which the lock operation of the acceleration sensor 100 is prevented. Noise generation from the vicinity can be surely prevented.

  The friction lever 72 is fitted to the center hub 71 and connected to the center hub 71 so as to rotate together with the center hub 71 by a frictional force. The friction lever 72 extends radially outward from the base 74 and has a drive gear on the outer peripheral surface. Since the arm portion 75 provided with 79 is provided, the release timing of the operation state of the lock cancellation mechanism can be arbitrarily set by setting the length of the arm portion 75.

  Since the pitch circle diameter DA of the drive gear 79 of the friction lever 72 is larger than the pitch circle diameter DB of the driven gear 92 of the switch lever 90, the swing of the friction lever 72 is accelerated and transmitted to the switch lever 90. The lock cancellation mechanism 70 can be released in a short time.

  Further, since the frictional force between the center hub 71 and the friction lever 72 is applied by the clamp spring 73 that urges the base 74 of the friction lever 72 in the direction of reducing the diameter, the magnitude of the frictional force is controlled by the lock cancel mechanism 70. The center hub 71, that is, the spindle 10 can be reliably rotated against the frictional force even after the friction lever 72 is restricted from swinging. .

  Further, since the bearing plate 60 is provided with a pair of protrusions 61 and 62 that limit the swing range of the friction lever 72, the number of teeth that can switch between the operating state and the operated state of the lock canceling mechanism 70 is driven. The gear 79 and the driven gear 92 can be configured, resulting in a compact design.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

1 Seat belt retractor 10 Spindle 13 Frame 20 Lock dock (lock member)
30 Steering wheel 34 Tooth part 60 Bearing plate 70 Lock cancel mechanism 71 Center hub 72 Friction lever 73 Clamp spring 74 Base part 75 Arm part 79 Drive gear 90 Switch lever 92 Driven gear 94 Acceleration sensor lock cancel part 95 Coil spring (biasing member)
100 Acceleration sensor 103 Acceleration sensor lever DA Pitch circle diameter DB of drive gear Pitch circle diameter of driven gear

Claims (6)

A spindle that is rotatably supported by the frame and on which the webbing is wound,
A locking member that locks rotation of the spindle in the webbing pull-out direction by engaging with the frame;
A steering wheel that is rotatably supported by the spindle and that operates the lock member by causing a rotation delay with respect to the spindle;
An acceleration sensor lever that is engageable with a tooth portion formed on the outer peripheral surface of the steering wheel, detects an acceleration in a horizontal direction, and locks the pulling-out operation of the webbing;
A lock cancellation mechanism for blocking the lock operation of the acceleration sensor;
The lock cancellation mechanism comprises
A friction lever fitted with a center hub that rotates integrally with the spindle, and connected to the center hub so as to rotate integrally with a frictional force, and provided with a drive gear;
A driven gear that is rotatably supported by a bearing plate fixed to the frame and meshes with the drive gear of the friction lever, and an acceleration sensor lock that prevents engagement between the acceleration sensor lever and a tooth portion of the steering wheel. A switch lever having a cancellation part;
With
When the spindle rotates in the winding direction of the webbing, the acceleration sensor lock canceling unit prevents the locking operation of the acceleration sensor, and when the spindle rotates in the drawing direction of the webbing, A seat belt retractor characterized by allowing a locking operation.   The seat belt retractor according to claim 1, wherein the lock canceling mechanism includes a biasing member that biases the switch lever in a direction that prevents the locking operation of the acceleration sensor. The friction lever is fitted to the center hub and is connected to the center hub so as to rotate together with the center hub by a frictional force, and extends radially outward from the base to provide the drive gear on the outer peripheral surface. The seat belt retractor according to claim 1, further comprising: an arm portion formed on the seat belt.   The seat belt retractor according to claim 1 or 2, wherein a pitch circle diameter of the drive gear of the friction lever is larger than a pitch circle diameter of the driven gear of the switch lever.   2. The seat belt retractor according to claim 1, wherein the frictional force between the center hub and the friction lever is applied by a clamp spring that urges the friction lever in a direction to reduce the diameter of the base portion.   2. The seat belt retractor according to claim 1, wherein any one of the bearing plate and the cover member facing the bearing plate includes a swing limiting member that limits a swing range of the friction lever.

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