JPH037232Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The invention is used in a seat belt device for protecting occupants during vehicle emergencies, and is used to stop the webbing pull-out operation of a retractor that winds up webbing for restraining occupants during vehicle emergencies. This invention relates to a locking mechanism for a webbing retractor.

[Prior art]

In the webbing take-up device, the webbing for restraining the occupant is wound around the take-up shaft, and in the event of a vehicle emergency, a lock mechanism is activated to stop rotation in the direction of pulling out the webbing, thereby restraining the occupant. There is.

In this lock mechanism, a lock plate is attached to the webbing take-up shaft and rotated together with the webbing take-up shaft, and in the event of a vehicle emergency, this lock plate is moved in the radial direction and engages with the internally toothed ratch wheel. The device can be downsized.

A common structure for attaching this lock plate to the winding shaft is a structure in which a pin is protruded from a portion eccentric from the axis of the winding shaft, and the lock plate is pivotally supported by this pin. However, with this mounting structure, in the event of a vehicle emergency, the lock plate that engages with the internally toothed ratchet wheel receives a large rotational force from the winding shaft, so a large load acts on the pin provided on the winding shaft.

[Purpose of invention]

Taking the above facts into consideration, the present invention allows the lock plate to be attached to the take-up shaft without requiring precision machining, and has a strong structure that ensures that the rotational force of the take-up shaft is absorbed in the event of a vehicle emergency. The object is to obtain a locking mechanism for a webbing retractor that can be supported.

[Summary of the idea]

In the present invention, by inserting a protrusion extending in the radial direction of the take-up shaft into a recess formed approximately at the center of the lock plate, the lock plate can be rotated relative to the take-up shaft by a predetermined angle, and the take-up shaft protrusion Since the projection further projects in the radial direction to prevent the lock plate from moving in the axial direction, a bearing structure such as a pin and a hole that fits into the pin is unnecessary.

[Example of idea]

FIG. 1 shows an exploded perspective view of an embodiment of a webbing retractor to which a locking mechanism according to the present invention is applied. In this winding device, frame 10
is fixed to the vehicle body by a mounting bolt (not shown). A pair of leg plates 12 and 14 extend parallel to each other from both sides of the frame 10, and have coaxial shaft holes 16 and 18, respectively.
have.

A winding shaft 20, which is also shown in FIG. 2, is supported in these shaft support holes 16 and 18.
One end of the occupant restraint webbing is secured to a through hole 21 that is radially penetrated into the center of the vehicle. The webbing for occupant restraint is on the take-up shaft 2.
The webbing is wound in a layered manner, and the occupant can attach the middle part of the webbing by engaging the tongue plate attached to the end of the webbing with a buckle device attached to the vehicle body.

The winding shaft 20 has a core metal 20 formed from a thick plate material.
A synthetic resin layer 20B is integrally molded around A and has a cylindrical outer shape.

An end portion of the core metal 20A protrudes from one longitudinal end of the synthetic resin layer 20B, and a protruding portion 2 extending in the radial direction of the winding shaft 20 as shown in FIG.
It has become 0C. The tip of the protrusion 20C is provided with an L-shaped protrusion 20D as shown in FIG. This protrusion 20D protrudes further in the radial direction than the protrusion 20C,
As a result, the protrusion 20C and the protrusion 20D form a recess 20E as shown in FIG.

These recesses 20E are for inserting lock plates 22, 24 arranged around the winding shaft 20. That is, each of the lock plates 22 and 24 has a substantially C-shape with a substantially U-shaped cutout recess 26 formed in the center thereof, and a radial protrusion 20C in the winding direction is inserted into this recess 26. It is adapted to rotate together with the winding shaft 20. The width of the cutout recess 26 is slightly larger than the width of the protrusion 20C, and the width of the notch 26 is slightly larger than that of the protrusion 20C.
2 and 24 can rotate relative to the winding shaft 20 by a predetermined angle.

Claw portions 28 and 30 are formed at one ends of these lock plates 22 and 24, respectively, and correspond to internally toothed ratchet foils 32 which are secured to the leg plate 12.

Furthermore, a pair of pins 34 and 36 protrude from the lock plates 22 and 24, respectively, and are inserted into elongated holes 40 formed in the lock ring 38. This lock ring 38 is pivotally supported by a small-diameter shaft portion 20F protruding from the axial center portion of the winding shaft 20, so that it can rotate relative to the winding shaft 20. Also, this lock ring 38
A torsion coil spring 44 is interposed between the holder 42 and the holder 42 attached to the tip of the take-up shaft small diameter shaft portion 20F. 1
It is urged to rotate in the direction of arrow A in the figure. Therefore, the lock ring 38 is biased by the torsion coil spring 44 to the lock plate 22, as shown in FIG.
24 pins 34, 36 are housed in one end of the elongated hole 40 to space the lock plate pawls 28, 30 from the internally toothed ratch wheel 32.

However, when the take-up shaft 20 suddenly rotates in the direction of pulling out the webbing, this lock ring 38 resists the biasing force of the torsion coil spring 44 and causes a rotation lag, and when this rotation lag occurs, the lock plates 22 and 24 are locked in the elongated hole 40. The lock plate pawls 28, 30 are guided so as to be movable in the longitudinal direction, thereby guiding the lock plate pawls 28, 30 in a direction toward the internal toothed ratchet wheel 32.

Next, the operation of this embodiment will be explained.

During normal vehicle operation, when the occupant wearing the webbing changes his or her driving position, the take-up shaft 20 rotates as the webbing is pulled out and taken up, but this rotation is performed at a relatively low acceleration.
rotates following the winding shaft 20, and no relative rotation occurs.

During this rotation, the lock plates 22 and 24 do not fall off the winding shaft 20 because the recessed portion 26 is prevented from moving in the axial direction of the winding shaft 20D.

When the vehicle enters an emergency state at the time of a collision, the occupant moves violently in the direction of the collision, so the webbing is suddenly pulled out from the take-up shaft 20, and the take-up shaft 20 rapidly rotates in the direction of pulling out the webbing. Therefore, the lock wheel 38 has a rotation delay with respect to the winding shaft 20, and as a result, the lock plates 22, 24 are rotated against the pins 34, 36.
moves within the elongated hole 40 and moves in the radial direction as shown in FIG. This causes the lock plate pawls 28, 30 to mesh with the internally toothed ratchet wheel 32.

Since the lock plates 22 and 24 can rotate relative to the take-up shaft 20 by a predetermined angle, the take-up shaft 20 is also prevented from rotating in the webbing drawing direction.
As a result, the occupant is securely restrained by the webbing.

Even in such a locked state, the lock plates 22 and 24 are prevented from moving in the axial direction of the winding shaft by the protrusion 20D, so that the internal toothed ratchet wheel 32
The mesh will not disengage, and the rotation of the winding shaft will surely stop. Also, the lock plates 22, 2
4 is a protrusion 20C of the winding shaft 20 via the recess 26
Unlike the conventional structure in which the winding shaft 20 is attached to the winding shaft 20 using a shaft support structure, it is possible to reliably support the large rotational force of the winding shaft 20 even in a vehicle emergency.

A ratchet foil 46 is carved on the outer periphery of the lock wheel 38, and an acceleration sensor for detecting vehicle acceleration is attached to the ratchet foil 4 in case of a vehicle emergency.
6, the rotation of the lock ring 38 in the webbing pull-out direction is stopped, so that the pull-out rotation of the winding shaft can be quickly stopped.

Although the above embodiment shows a webbing retractor provided with a pair of lock plates, the present invention can also be applied to a retractor having one or three or more lock plates.

[Effect of idea]

In this invention, the lock plate is pivotally supported by a recess formed in the center and a radial protrusion of the take-up shaft, and the lock plate is moved in the axial direction by a protrusion formed further radially from the protrusion of the take-up shaft. Therefore, the lock plate can be reliably supported on the winding shaft with a simple structure.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing a webbing take-up device to which the lock mechanism of the present invention is applied, Fig. 2 is a front view of the take-up shaft used in this embodiment, and Fig. 3 is a view of the lock plate and internally toothed ratch foil. FIG. 4 is a front view showing the arrangement of the vehicle in a normal state, and FIG. 4 is a front view showing the operating state of FIG. 20... Winding shaft, 20A... Core metal, 20B...
Synthetic resin, 20C...Protrusion, 20D...Protrusion,
22, 24...Lock plate, 32...Internal tooth ratchet foil.

Claims (1)

[Scope of utility model registration request] A lock for a webbing take-up device in which a lock plate that rotates together with a webbing take-up shaft moves in the radial direction in the event of a vehicle emergency, and the claws of the lock plate engage with internal ratchets to stop the rotation of the webbing take-up shaft in the webbing pull-out direction. It is a mechanism,
The lock plate can be rotated relative to the webbing take-up shaft by a predetermined angle by being inserted into a concave portion extending in the radial direction of the webbing take-up shaft and formed approximately at the center of the lock plate. A webbing take-up device comprising: a protrusion that extends from the protrusion in the radial direction of the take-up shaft, and a protrusion that prevents the lock plate from moving in the axial direction of the take-up shaft. lock mechanism.