JPH0245089Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a webbing take-up device for pivotally supporting a take-up shaft of webbing for restraining an occupant, which is used in a seat belt device for protecting an occupant in a vehicle emergency.

[Prior art]

In the seat belt device, the webbing for restraining an occupant is wound onto a take-up device, and the take-up device is pivotally supported by a frame, which is attached to the vehicle body. A ratchet wheel is fixed to this take-up shaft and rotates together with the take-up shaft, and in the event of a vehicle emergency, a pawl pivotally supported on the frame engages with the ratchet wheel to stop the rotation of the webbing take-up shaft.

Both ends of the steel plate of this pawl are inserted into shaft support holes drilled into the frame so that the pawl can rotate, and when the vehicle is in normal condition, it is separated from the ratchet wheel by its own weight or elastic biasing force.

However, when this pawl engages with the ratchet wheel in a vehicle emergency, it receives a large rotational force from the ratchet wheel, so it is necessary to contact the shaft support hole of the frame over a large area to ensure that the winding shaft rotational force is supported by the frame. be. Therefore, the area of contact of this pawl with the frame must be large, so that the width dimensions of both ends of the pawl are greater than a predetermined value.

As a result, when the part of the pawl farthest from the center of rotation comes into contact with the shaft support hole of the frame, a large rotational friction and low drag force is applied to the pawl.

[Purpose of invention]

The purpose of the present invention is to provide a webbing retractor that can reduce the rotational resistance of the pawl and, in the event of a vehicle emergency, can contact the frame over a wide area and reliably support the rotational torque of the rewind shaft. be.

[Summary of the idea]

In the webbing retractor according to the present invention, a wide width receiving part and a small width receiving part provided at the tip of the wide width receiving part are formed at the end of the pawl, and a pivot bushing is attached to the frame. A first support part that accommodates the narrow width receiving part, and a second supporting part that rotatably accommodates the wide width receiving part within a predetermined angular range.
a support part is provided, the first support part tightly accommodates an end of the narrow width receiving part on the rotation center side and an end of the width opposite to the rotation center, and the second support part is arranged on the opposite side of the rotation center of the wide width receiving part. The structure allows the pawl to rotate smoothly in a non-contact manner, and in the event of a vehicle emergency, the pawl rotates over a predetermined angle so that the wide receiving part and the second support part come into contact with each other over a wide area to safely support a large load. It's summery.

[Example of idea]

In the webbing retractor of this embodiment shown in FIG. 1, a frame 10 is fixed to a vehicle body, and leg plates 12 and 14 project from both sides of the frame 10 in parallel with each other. A take-up shaft 16 is pivotally supported by these leg plates 12 and 14, and one end of an occupant restraining webbing 18 is wound around the center of the take-up shaft 16. The other end of the webbing 18 is secured to the vehicle body by a buckle device and a tongue plate that engages with the buckle device, thereby allowing the occupant to attach the middle portion of the webbing 18.

Ratchet foils 20 are fixed to the winding shaft 16 on both sides of the webbing 18, and the leg plates 12, 1
This corresponds to the pawl 22 which is pivoted to the pawl 22. To explain the shaft support means for the pawl 22, substantially triangular and coaxial shaft support holes 24 and 26 are bored in the frame leg plates 12 and 14, and the shaft support holes 24 and 26 are connected to the shaft support holes 24 and 26 as shown in FIG. Pivot bushes 28 shown in FIGS. 4 to 4 are respectively attached. This shaft support bush 28 is made of synthetic resin, and the shaft support hole 2
4, 26, and a second support part 30 that communicates with the first support part 30 and partially increases the depth of the pivot bush 28 from the bottom part 30A of the first support part. It has a support part 32. The first support part 30 and the second support part 32 are both approximately triangular in shape as shown in FIGS.
It corresponds to 6.

The wide receiving part 34 is accommodated in the first support part 30, and its width L is the same as the longitudinal dimension W of the first support part 30.
On the other hand, the width dimension M of the narrow width receiving part 36 is approximately equal to the longitudinal dimension N of the second support part 32, or has only a slight gap. Therefore, the first support part 30 tightly receives the narrow width receiving part 36, and the end 34A of the wide width receiving part 34 on the opposite side to the narrow width receiving part 36 is separated from the inner peripheral surface of the first supporting part 30. ing. This end 34
End portion 3 of the width receiving portion 36 located on the opposite side of A
6A is the rotation center of the pawl 22, and the end portion 34A of the wide width receiving portion 34 is located at the farthest part from the rotation center during rotation. With this, the wide width receiving part 3
4 can freely rotate within the first support part 30 by a predetermined angle.

Further, the tip of the width receiving portion 36 is formed into an arc shape, and the tip portion of the arc is in contact with the bottom portion 32A of the second support portion 32. With this, Paul 2
2 is restrained from moving in the longitudinal direction (vertical direction in FIG. 2) at the bottom of the second support part 32, which also reduces frictional resistance during rotation, and the wide receiving part 34
The side surface 34B and the stepped portion 38 between the wide width receiving portion 34 and the pawl engaging portion 22A are spaced apart from the boss portion 28A of the pivot bushing 28.

The pawl 22 receives rotational force from an acceleration sensor (not shown) such as a pendulum, and rotates to mesh with the ratchet wheel 20 in the event of a vehicle emergency. Further, the shaft support hole 26 of the frame leg plate 14 is formed with a long hole portion 27 for inserting the pawl 22 therein.

Next, the operation of this embodiment will be explained.

In the normal state of the vehicle, the pawl 22 is separated from the ratchet wheel 20, so the winding shaft 16 can freely rotate.

In this state, the pawl 22 has an end portion 34A and a side surface 34B of the wide width receiving portion 34 at the first position of the pivot bushing 28.
Since it is spaced apart from the support part 30, the friction resistance hole is small and it can be easily rotated.

When the vehicle is in an emergency situation such as a collision, an acceleration sensor (not shown) rotates the pawl 22.
The pawl 22 rotates around the end 36A of the width receiving part 36 and engages with the ratchet foil 20. As a result, the rotation of the take-up shaft 16 in the webbing pull-out direction is stopped, and the occupant is restrained by the webbing 18. During such rotation of the pawl 22, the wide receiving portion 34 of the pawl 22 can rotate smoothly without coming into contact with the bearing bush 28, so that the pawl 22 can be quickly engaged with the ratchet wheel 20.

Further, the occupant thrown out by inertia in the collision direction applies a large tension to the webbing 18, causing the take-up shaft 16 to undergo a large rotation in the webbing pull-out direction. In the pawl 22 that receives this force, the wide receiving portion 34 is pressed against the pivot bush 28, and comes into contact with the pivot holes 24, 26 of the frame leg plate 12 via the bush 28. At the time of this contact, the wide receiving portion 34 contacts the shaft support hole of the frame in the area shown by the shaded area in FIG. 2, so it can contact the frame over a wide area and can support a large load. The state in which the occupant is restrained by the webbing 18 is ensured.

Note that in the above embodiment, the boss portion 28A of the pivot bush 28 is brought into contact with the stepped portion 38 of the pawl 22 without bringing the tip of the knife receiving portion 36 into contact with the bottom portion 32A of the second support portion 32. Directional movement may be restricted.

[Effect of idea]

As explained above, in the webbing retractor according to the present invention, the pawl is formed with a wide width receiving part and a small width receiving part, and the first bearing bush is attached to the frame.
Corresponding to the support part and the second support part, the first support part tightly accommodates the tip end on the rotation center side of the narrow width receiving part and the end opposite to the rotation center, and the second support part tightly accommodates the rotation center side end part of the width width receiving part. Since the wide receiver is rotatably accommodated within a predetermined angle range without contacting the opposite surface of the center,
The pawl rotates smoothly, and the wide width receiving part can reliably support the rotational torque of the winding shaft in the event of a vehicle emergency.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing an embodiment of the webbing retractor according to the present invention, Fig. 2 is a sectional view taken along the line in Fig. 1 showing an assembled state, and Fig. 3 shows a pivot bush. The front view shown in FIG. 4 is a sectional view of the pivot bush. 10...Frame, 16...Take-up shaft, 18...
Webbing, 20... Ratchet foil, 22...
... Paul, 30... First support part, 32... Second support part, 34... Wide width receiving part, 36... Small width receiving part.

Claims (1)

[Scope of utility model registration request] A locking pawl for stopping rotation of a take-up shaft is a webbing winding device which is rotatable by having both ends pivotally supported on a frame, and has a wide width receiving part at the end of the pawl and a narrow width receiving part at the tip of the wide width receiving part. and a pivot bush attached to the frame is provided with a first support part for accommodating the narrow width receiving part and a second support part for rotatably accommodating the wide width receiving part within a predetermined angular range; The supporting part tightly accommodates the end of the narrow width receiving part on the rotation center side and the end opposite to the rotation center, and the second supporting part accommodates the surface of the wide width receiving part opposite to the rotation center in a non-contact manner. Featured webbing retractor.