JPH0637021U - Webbing take-up device - Google Patents

Abstract

(57) [Abstract] [Purpose] A webbing take-up that can prevent the webbing from being pulled out instantly when the vehicle is rapidly decelerated when the vehicle is normally worn, and that allows the webbing to be pulled out easily from the full state of winding the webbing. Get the device. [Structure] A connecting gear 70 is arranged on a side of a rotor 44 fixed to a winding shaft 20, and a tooth groove 4 of the rotor 44 is arranged.
8 is in mesh. The connecting gear 70 can mesh with the tooth groove 42 of the lock wheel 38 by moving in the axial direction. The connecting gear 70 corresponds to the convex portion 60 of the cam 52 that rotates in synchronization with the winding shaft 20.
When the whole amount is wound up, it is pressed by the convex portion 60 and moves. Therefore, at this time, the connecting gear 70 remains engaged with the tooth groove 48 of the rotor 44, and the tooth groove 4 of the lock ring 38 remains.
It also meshes with 2 and connects them together. For this reason,
The relative rotation between the winding shaft 20 and the lock wheel 38 is prevented, and the end lock is prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a webbing take-up device capable of instantaneously stopping the rotation of the take-up shaft in the webbing pull-out direction by actuating the locking means by suddenly pulling out the webbing.

[0002]

[Prior art]

 The webbing take-up device equipped on the vehicle causes a delay in rotation of the lock wheel in response to the sudden withdrawal of the webbing, and the relative rotation between the take-up shaft and the lock wheel actuates the locking means to rotate the take-up shaft. There is a method in which the webbing withdrawal direction is stopped to instantaneously prevent the webbing from being withdrawn (referred to as WSIR).

In the webbing retractor of this type, when the operation of the lock means is released, the operation of the lock means is released by rotating the take-up shaft a little in the webbing take-up direction.

By the way, when the occupant releases the wearing of the webbing, since the winding shaft is biased in the webbing winding direction by the biasing means, the webbing is rapidly wound when the passenger releases the webbing. Sometimes. When the winding of the webbing is completed in such a state, the rotation of the winding shaft suddenly stops, and the state becomes the same as when the webbing is suddenly pulled out, and the locking means may operate.

Therefore, a webbing retractor that solves this problem has been proposed (Japanese Utility Model Publication No. 62-95058).

A webbing retractor of this type will be described with reference to FIG. A lock wheel 106 is pivotally supported on one end 104A of a winding shaft 104 for winding the webbing 102. The lock wheel 106 is provided with a pair of lock plates 112 that stop the rotation of the winding shaft 104 by meshing with an internal gear wheel 110 fixed to the frame 108. A rotor 114 that rotates integrally with the winding shaft 104 is connected to one end 104A of the winding shaft 104. A boss portion 116A of a cam 116 is fitted in the rotor 114, and the cam 116 is rotatable by a frictional force with the rotor 114. The cam 116 is sandwiched by a friction spring 120 provided on the cover 118 with a force stronger than the frictional force with the rotor 114.

A torsion coil spring 122 is disposed between the lock ring 106 and the rotor 114, and the torsion coil spring 122 urges the lock ring 106 in the webbing pull-out direction (arrow B direction in FIG. 7). .

Further, a protrusion 124 is formed on the lock wheel 106, and a pole 126 pivotally supported by a pin 114 A of the rotor 114 can come into contact with the protrusion 124.

In the webbing retractor having the above structure, when the take-up shaft 104 rotates in the webbing take-up direction (direction of arrow A in FIG. 7) during take-up of the webbing, the rotor 114 also rotates integrally. In this case, the rotational force of the rotor 114 is transmitted to the cam 116 via a predetermined frictional force, but the cam 116 is sandwiched by the friction spring 120 and is not rotated.

Therefore, one end 126A of the pole 126 abuts on the notch surface 116B of the cam 116, and the pole 126 is rotated about the pin 114A in the arrow F direction. As a result, the pole 126 engages with the protrusion 124 of the lock wheel 106 and prevents relative rotation between the lock wheel 106 and the winding shaft 104.

As a result, since the winding shaft 104 is not locked by the lock plate 112 when the webbing is fully wound, the webbing 102 can be easily pulled out.

By the way, even when the webbing 102 pulled out in response to the change in the posture of the occupant when the webbing is mounted is wound up, the lock wheel 106 and the winding shaft 104 are in the relative rotation preventing state similarly to the above-described operation. It is said that

Therefore, when the vehicle is suddenly decelerated at this time, the take-up shaft 104 and the lock wheel 106 are not in a relatively rotatable state, so that the take-up shaft 104 and the lock wheel 106 are suddenly moved by the occupant's sudden movement. Since the webbing 102 is pulled out until the state where the webbing is relatively rotatable, it takes a long time until the pulling-out of the winding shaft 104 is stopped. In order to shorten the time until the webbing 102 is pulled out, it is necessary to improve the dimensional accuracy of the cam 116 and the pole 126, which causes a cost increase.

[0014]

[Problems to be solved by the device]

 In consideration of the above facts, the present invention can prevent the webbing from being pulled out in an instant when the vehicle is rapidly decelerated when the webbing is normally attached, and can easily pull out the webbing from all the winding states of the webbing. The purpose is to obtain a take-up device.

[0015]

[Means for Solving the Problems]

 A webbing take-up device according to the present invention is formed in a disk shape having a take-up shaft for taking up a webbing mounted on an occupant and a tooth groove on an outer peripheral wall, and is coaxial with the take-up shaft and relatively rotatable. A lock wheel that is arranged between the take-up shaft and the lock wheel and has a rotation delay with respect to the take-up shaft due to abrupt withdrawal of the webbing. Is formed in a disk shape having a tooth groove on the outer peripheral wall, is arranged coaxially with the lock ring near the lock ring, and is connected to the take-up shaft so that the take-up shaft is always provided. The rotor that rotates together with the lock ring and the rotor are supported such that their axes are parallel to each other and movably along the axial direction, and they are arranged so as to mesh with the tooth grooves on the outer circumference of the rotor. Move along By the above, while maintaining the meshed state with the rotor, the meshing gear meshes with the tooth groove on the outer periphery of the lock ring to integrally connect the rotor and the lock gear, and the connecting gear prevents the relative rotation. There is a convex part that is connected to the shaft via a gear and rotates in synchronization with the rotation of the take-up shaft, and presses the connecting gear to move in the axial direction when the take-up amount of the webbing exceeds a predetermined amount. And a formed cam.

[0016]

[Action]

 In the webbing retractor having the above structure, in a normal state, the connecting gear meshes only with the tooth groove on the outer circumference of the rotor and is separated from the lock wheel. Therefore, the lock wheel can rotate relative to the winding shaft. For this reason, if the vehicle falls into a sharp deceleration state when the webbing is installed, the lock wheel and the take-up shaft rotate relative to each other, and the take-up shaft is prevented from rotating by the locking means, so that the webbing is stopped instantaneously. Be done.

When the drawn-out webbing is taken up by the take-up shaft and the take-up amount of the webbing exceeds a predetermined amount (for example, when the webbing is completely taken up), the convex portion of the cam is connected. Press the gear to move it in the axial direction. As a result, the connecting gear also meshes with the tooth groove on the outer periphery of the lock wheel, and the rotor and the lock wheel are integrally connected. Therefore, relative rotation between the rotor, that is, the take-up shaft and the lock wheel is prevented, and the lock wheel is prevented from being delayed in rotation with respect to the take-up shaft.

As a result, the locking means does not operate, the winding shaft can freely rotate, and the webbing can be pulled out easily.

As described above, in the webbing retractor according to the present invention, it is possible to prevent the webbing from being pulled out instantly when the vehicle is suddenly decelerated in the normal webbing mounting state. Can be pulled out easily.

[0020]

【Example】

 FIG. 1 shows a webbing retractor 10 according to an embodiment of the present invention.

In the webbing retractor 10, the frame 11 has a pair of legs 12 and 14 extending from both sides of the base portion in parallel with each other. A winding shaft 20 is rotatably supported by the legs 12 and 14, and one end of a webbing 22 worn by an occupant is locked to the winding shaft 20.

One end of the winding shaft 20 in the longitudinal direction projects to the outside of the leg portion 12, and the inner end of the mainspring 27 is locked to this projection. An outer end portion of the mainspring spring 27 is fixed to a leg portion 12 and is locked to a spring cover 29 that accommodates the mainspring spring 27, whereby the winding shaft 20 is wound by the urging force of the mainspring spring 27. The webbing 22 is wound in layers by being biased and rotated in the direction (arrow A direction in FIG. 1).

The other end of the winding shaft 20 projects to the outside of the leg portion 14, and a forked portion 20A is formed on this projection. Around the bifurcated portion 20A, as shown in FIGS. 2 and 3, a pair of lock plates 24 and 25 that form a part of the locking means are arranged. Each of these lock plates 24, 25 has a substantially C-shape with a substantially U-shaped cutout recess 26 formed in the center thereof, and the forked portion 20A is located in the cutout recess 26. As shown in FIG. 2, the notch recess 26 has a width dimension (vertical length in FIG. 2) slightly larger than that of the forked portion 20A (vertical length in FIG. 2). Is rotatable relative to the winding shaft 20 by a predetermined angle.

Claw portions 28 and 30 are formed at one ends of the lock plates 24 and 25, respectively, and are fixed to the leg portion 14 to form an internal gear wheel which is a locking means together with the lock plates 24 and 25. Opposite the 32 inner teeth.

Further, a pair of pins 34 and 36 are respectively provided on the lock plates 24 and 25 so as to project, and are inserted into the long holes 40 formed in the lock ring 38.

The lock ring 38 has a disc shape as a whole and ratchet teeth 39 formed on the outer periphery thereof. The lock ring 38 is axially supported by the small diameter shaft portion 20 B protruding from the axial center portion of the winding shaft 20. It can rotate relative to 0. When the lock wheel 38 rotates relative to the winding shaft 20 (rotation delay), the pins 34 and 36 inserted into the elongated holes 40 are guided so that the lock plates 24 and 25 move toward the internal gear wheel 32. Be moved. The lock wheel 38 is a so-called WSIR mechanism that causes a rotation delay with respect to the abrupt rotation of the winding shaft 20 due to the abrupt withdrawal of the webbing 22, and a pawl lever 80 described later engages with the ratchet teeth 39. The rotation is also blocked by doing.

As shown in FIGS. 4 and 5, a tooth groove 42 is formed over the entire circumference at one end in the thickness direction of the outer periphery of the lock ring 38 (the side opposite to the ratchet teeth 39). A connecting gear 70 that meshes with a rotor 44, which will be described later, can mesh with each other.

On the other hand, a rotor 44 is arranged on the side of the lock wheel 38. The rotor 44 is formed in a disk shape having substantially the same diameter as the lock wheel 38, is arranged near the lock wheel 38, and is fixed to the tip of the small diameter shaft portion 20B of the winding shaft 20. A through hole 46 is formed in the axial center portion of the rotor 44, and the small diameter shaft portion 20B of the winding shaft 20 is fitted and fixed in the through hole 46, and the rotor 44 rotates integrally with the winding shaft 20. It is a composition.

A tooth groove 48 is formed on the outer peripheral wall of the rotor 44 over the entire circumference. The tooth groove 48 corresponds to the tooth groove 42 of the lock ring 38 described above, is provided with the same shape and the same number of teeth, and is meshed with a connecting gear 70 described later.

A torsion coil spring 50 is arranged between the lock wheel 38 and the rotor 44. The coil portion of the torsion coil spring 50 is fitted onto the boss portion 38A of the lock ring 38, one end of which is locked to the lock ring 38 and the other end of which is locked to the rotor 44. As a result, the lock wheel 38 is urged and rotated by the urging force of the torsion coil spring 50 in the webbing pull-out direction (arrow B direction in FIG. 1). Therefore, as shown in FIG. 2, the lock ring 38 receives the pins 34 and 36 of the lock plates 24 and 25 in one end portion of the elongated hole 40 by the urging force of the torsion coil spring 50, and the claw portions 28 and 30 inside. It is separated from the tooth gear wheel 32.

On the other hand, a disc-shaped cam 52 is arranged in the direction opposite to the leg portion 14 of the rotor 44. A through hole 54 is formed in the shaft center portion of the cam 52, and the small diameter shaft portion 20B of the winding shaft 20 penetrates and is supported by the through hole 54, and the cam 52 rotates relative to the winding shaft 20. It is like this.

On a part of the outer periphery of the cam 52, a convex portion 60 is formed to project toward the leg portion 14 along the axial direction, and can be pressed corresponding to a connecting gear 70 described later. Further, a protrusion 61 is similarly formed on the side of the protrusion 60 along the axial direction, and corresponds to a pawl lever 80 described later.

Further, a concave portion 56 is formed on the surface of the cam 52 opposite to the leg portion 14, and internal teeth 58 are formed on the inner peripheral surface of the concave portion 56.

A spur gear 62 formed at the tip of the small-diameter shaft portion 20 B of the winding shaft 20 projects from a through hole 54 formed in the shaft center portion of the cam 52.

In the recess 56 of the cam 52, a gear 64 is arranged between the spur gear 62 and the internal teeth 58 of the cam 52. The gear 64 is axially supported by a pin 68 protruding from the inside of the sensor cover 66, a large gear portion 64A meshes with the spur gear 62, and a small gear portion 64B meshes with the internal teeth 58 of the cam 52. As a result, when the spur gear 62 rotates together with the winding shaft 20, the rotational force is transmitted via the gear 64, and the cam 52 rotates in the direction opposite to the winding shaft 20. In this case, the spur gear 62, the gear 64 (the large gear portion 64A, the large gear portion 64A, and the like) are rotated so that the cam 52 makes one rotation with respect to the rotation of the winding shaft 20 during the entire winding state of the webbing 22 to the fully extended state. The number of teeth of the small gear portion 64B) and the inner teeth 58 and the like are set.

A connecting gear 70 is arranged on the side of the rotor 44 and the cam 52. The connecting gear 70 is supported by a fixing plate 74 extending inside the sensor cover 66 such that its shaft 72 is axially parallel to the lock ring 38 and the rotor 44 and is movable along the axial direction. And meshes with the tooth groove 48 on the outer periphery of the rotor 44. The connecting gear 70 also corresponds to the tooth groove 42 on the outer periphery of the lock ring 38, and moves along the axis to maintain the meshing state with the tooth groove 48 of the rotor 44. It can be engaged with the tooth groove 42 of the lock wheel 38. Therefore, in this state, the rotor 44 and the lock wheel 38 are integrally connected by the connecting gear 70, and the relative rotation between the rotor 44 and the lock wheel 38 is prevented.

Further, in the connecting gear 70, the end portion on the cam 52 side corresponds to the convex portion 60 of the cam 52. That is, when the convex portion 60 of the cam 52 reaches the connecting gear 70, the convex portion 60 is pressed by this and moves in the axial direction to mesh with the tooth groove 42 of the lock wheel 38.

A compression coil spring 76 is wound around the shaft 72 of the connecting gear 70. One end of the compression coil spring 76 is in contact with the fixed plate 74, and the other end is in contact with the flange 78 fixed to the shaft 72. As a result, the connecting gear 70 is biased by the compression coil spring 76 in the direction away from the lock ring 38.

A pawl lever 80 and a ball 82 are arranged immediately below the lock wheel 38.

The pawl lever 80 is substantially L-shaped, and is rotatably supported by a pair of arm portions 86 projectingly formed at one end of the sensor holder 84 fixed to the outside of the leg portion 14. The tip of the pawl lever 80 is bent upward in a substantially U shape to form an elastically deformable engaging portion 88, which engages with the ratchet teeth 39 of the lock wheel 38 to prevent the lock wheel 38 from rotating. be able to.

On the other hand, the ball 82 is arranged in the cone receiving portion 90 of the sensor holder 84, and is designed to climb up inside the cone receiving portion 90 when a large acceleration is applied. Further, the umbrella portion 92 of the pawl lever 80 rotatably supported by the arm portion 86 is placed on the ball 82, and the ball 82 is pushed up by climbing up the conical receiving portion 90, whereby the pawl lever 90. 80 is rotated so that the engaging portion 88 meshes with the ratchet teeth 39 of the lock wheel 38.

Further, the engaging portion 88 of the pawl lever 80 corresponds to the protruding piece 61 of the cam 52. That is, when the convex portion 60 of the cam 52 reaches the connecting gear 70, the projecting piece 61 also reaches directly above the pawl lever 80 and is interposed between the engaging portion 88 of the pawl lever 80 and the ratchet teeth 39 of the lock wheel 38. As a result, the engaging portion 88 is prevented from meshing with the ratchet teeth 39 of the lock wheel 38.

As described above, the webbing retractor 10 has a so-called webbing sensitive (WSIR) mechanism that senses a sudden pull-out of the webbing 22 and prevents the rotation of the take-up shaft 20, and a rapid vehicle deceleration state. It has a so-called DSIR structure that has a so-called body-sensitive (VS IR) mechanism that senses and blocks the rotation of the winding shaft 20.

Next, the operation of this embodiment will be described. In the webbing retractor 10 of this embodiment configured as described above, the frame 11 is attached to the vehicle body through the bolts. When the winding device 10 is used in a three-point type seat belt device of continuous webbing type, the webbing 22 pulled out from the winding shaft 20 has its end portion locked to the vehicle body through an anchor member. Then, the intermediate portion is folded back by the slip joint fixed to the vehicle body, and the tongue plate is attached to the intermediate portion between the anchor member and the slip joint so as to be slidable in the longitudinal direction.

Here, when the occupant seated on the seat wears the webbing 22, the webbing 22 is pulled out from the winding shaft 20, and the tongue plate is engaged with the vehicle device attached to the vehicle body. The occupant is put on the webbing.

In the case where the webbing 22 pulled out in this way is mounted, and when the webbing 22 is wound up in response to a change in the posture of the occupant, if the vehicle falls into a drastic deceleration state, the vehicle is locked. Relative rotation occurs between the wheel 38 and the winding shaft 20.

That is, the inertial force of the lock wheel 38 itself causes a rotation delay with respect to the winding shaft 20. Further, at the same time, the ball 82 climbs up inside the conical receiving portion 90 of the sensor holder 84, the umbrella portion 92 of the pawl lever 80 is pushed up, and the pawl lever 80 is rotated. As a result, the engaging portion 88 of the pawl lever 80 meshes with the ratchet teeth 39 of the lock wheel 38, and the rotation of the lock wheel 38 is blocked, which also causes relative rotation with the winding shaft 20.

By the relative rotation of the lock wheel 38, the lock plates 24 and 25 that rotate together with the winding shaft 20 have the pins 34 and 36 guided by the elongated holes 40 of the lock wheel 38 as shown in FIG. Thus, the claws 28 and 30 mesh with the internal gear wheel 32. As a result, the rotation of the take-up shaft 20 in the webbing pull-out direction is blocked, the pulling-out of the webbing 22 is instantaneously blocked, and the occupant is securely restrained by the webbing 22.

On the other hand, when the occupant gets off the vehicle, first, the engagement between the tongue plate and the bag device is released. As a result, the winding shaft 20 is rotated in the webbing winding direction (direction of arrow A in FIG. 1) by the urging force of the mainspring 27, and the webbing 22 is wound around the winding shaft 20. As the winding shaft 20 rotates in the webbing winding direction, the spur gear 62 also rotates in the webbing winding direction.

By the rotation of the spur gear 62, the gear 64 meshing with the spur gear 62 rotates in the direction of arrow C in FIG. 4 to transmit the rotational force of the spur gear 62 to the cam 52, which causes the cam 52 to move. Rotates in the clockwise direction in FIG.

When the winding amount of the webbing 22 exceeds a predetermined amount and the webbing 22 is completely wound up, the convex portion 60 of the cam 52 contacts the end portion of the connecting gear 70. As a result, the connecting gear 70 is moved in the direction of the lock ring 38 against the biasing force of the compression coil spring 76, and is locked while maintaining the meshing state with the tooth groove 48 of the rotor 44, as shown in FIG. It meshes with the tooth space 42 of the ring 38. As a result, the rotor 44 and the lock wheel 38 are integrally connected by the connecting gear 70, and the winding shaft 20 to which the rotor 44 is fixed and the lock wheel 38 are integrally rotated. That is, in this state, the lock wheel 38 and the winding shaft 20 do not rotate relative to each other, and the lock wheel 38 does not delay in rotation with respect to the winding shaft 20.

Further, at the same time, when the convex portion 60 of the cam 52 reaches the connecting gear 70, the protrusion 61 of the cam 52 also reaches directly above the pawl lever 80. Therefore, the protrusion 61 is interposed between the engaging portion 88 of the pawl lever 80 and the ratchet tooth 39 of the lock wheel 38, and the engaging portion 88 is prevented from meshing with the ratchet tooth 39 of the lock wheel 38. Be done. Therefore, also by this, the rotation of the lock wheel 38 is not blocked, and the lock wheel 38 does not delay in rotation with respect to the winding shaft 20.

As a result, the lock plates 24 and 25 do not mesh with the internal gear wheel 32, and the winding shaft 20 can freely rotate.

Therefore, when the occupant attaches the webbing 22 again from the fully wound state of the webbing 22 as described above, the webbing 22 can be easily pulled out by simply pulling the webbing 22.

Further, when the occupant pulls out the webbing 22, the take-up shaft 20 and the spur gear 62 rotate in the webbing pull-out direction (the arrow B direction in FIG. 1). Therefore, the gear 64 rotates in the direction of arrow D in FIG. 4 to transmit the rotational force of the spur gear 62 to the cam 52, and the cam 52 rotates counterclockwise in FIG. As a result, the convex portion 60 of the cam 52 is separated from the connecting gear 70, so that the connecting gear 70 is moved by the biasing force of the compression coil spring 76 in the direction away from the tooth groove 42 of the locking wheel 38, and the tooth groove 42 is moved. The engagement with is released. Therefore, the lock wheel 38 and the rotor 44, that is, the winding shaft 20 are again in a state in which they can rotate relative to each other.

Further, due to the rotation of the cam 52, the projecting piece 61 of the cam 52 is also separated from directly above the pawl lever 80, and the engagement portion 88 of the pawl lever 80 can be engaged with the ratchet teeth 39 of the lock wheel 38. Become.

Thus, as described above, when the vehicle is in a sudden deceleration state, the lock plates 24 and 25 are actuated to instantaneously prevent the webbing 22 from being pulled out, so that the occupant can be reliably restrained. .

As described above, in the webbing retractor 10, the webbing 22 can be instantaneously prevented from being pulled out when the vehicle is rapidly decelerated in the normal webbing mounted state. 22 can be easily pulled out.

In the webbing retractor 10 according to the present embodiment, a WSIR mechanism that delays the rotation of the lock wheel 38 in response to the sudden withdrawal of the webbing 22 to stop the rotation of the take-up shaft 20 in the webbing withdrawal direction. The configuration of a so-called DSIR having both the VSIR mechanism that senses the vehicle sudden deceleration state and prevents the rotation of the winding shaft 20 is described, but the present invention is not limited to this, and only the WSIR mechanism is configured. But of course it can be applied.

[0060]

[Effect of device]

 As described above, in the webbing retractor according to the present invention, it is possible to prevent the webbing from being pulled out instantly when the vehicle is rapidly decelerated in the normal webbing loaded state, and moreover, to easily pull out the webbing from the fully wound state of the webbing. It has an excellent effect that it can.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a webbing retractor according to an embodiment of the present invention.

FIG. 2 is a view taken along the line 2-2 in FIG. 1 in a state where the lock plate and the internal gear wheel are not meshed with each other.

3 is a view taken along the line 2-2 of FIG. 1 in a state where a lock plate and an internal gear wheel are engaged with each other.

4 is a cross-sectional view taken along the line 4-4 of FIG. 1 showing a connecting gear and peripheral components.

FIG. 5 is a cross-sectional view showing a relationship between a lock wheel, a rotor, a connecting gear, and the like when the webbing is pulled out.

FIG. 6 is a cross-sectional view corresponding to FIG. 5, showing a relationship among a lock wheel, a rotor, a connecting gear, and the like when the webbing is completely wound up.

FIG. 7 is an exploded perspective view showing a conventional webbing retractor.

[Explanation of symbols]

 10 webbing take-up device 20 take-up shaft 22 webbing 24 lock plate (locking means) 25 lock plate (locking means) 32 internal gear wheel (locking means) 38 lock ring 42 tooth groove 44 rotor 48 tooth groove 52 cam 60 convex portion 61 Projection piece 62 Spur gear 64 Gear 70 Joint gear

Claims (1)

[Scope of utility model registration request] 1. A take-up shaft for taking up a webbing mounted on an occupant, and a disk-like member having a tooth groove formed on an outer peripheral wall thereof. A lock wheel that causes a rotation delay with respect to the take-up shaft due to abrupt withdrawal, and a lock that is provided between the take-up shaft and the lock wheel and that operates due to the rotation delay of the lock wheel to prevent the take-up shaft from rotating. A rotor that is formed in a disk shape having a tooth groove on the outer peripheral wall, is disposed coaxially with the lock ring near the lock ring, and is connected to the winding shaft and always rotates with the winding shaft; The axis is parallel to the lock wheel and the rotor, and is supported so as to be movable along the axial direction, and is arranged in a state of meshing with the tooth groove on the outer periphery of the rotor, and by moving along the axis. With the rotor A coupling gear that meshes with a tooth groove on the outer periphery of the lock ring while maintaining the engaged state to integrally connect to each other to prevent relative rotation between the rotor and the lock ring, and is coupled to the winding shaft via the gear. And a cam having a convex portion that rotates in synchronism with the rotation of the take-up shaft and presses the connecting gear to move in the axial direction when the take-up amount of the webbing exceeds a predetermined amount. Webbing take-up device.