JP2842988B2 - Lock mechanism for webbing take-up device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock mechanism for a webbing take-up device for preventing a take-up shaft for taking up an occupant restraining webbing from rotating in a webbing pull-out direction to prevent the webbing from being pulled out when the vehicle decelerates. .

[0002]

2. Description of the Related Art As a lock mechanism of this kind, there are provided a lock plate which is linked to a take-up shaft around a take-up shaft and is rotated following the take-up shaft, and a take-up shaft which overlaps the lock plate. There is a structure in which a rotating wheel that is rotated in accordance with the winding shaft in association with the winding shaft is arranged.

In the lock mechanism having such a structure, the lock plate is disposed so as to be movable in a direction intersecting the axis of the winding shaft, and the rotating wheels are also linked to the lock plate. At this time, due to the inertial force (so-called webbing sensing type) due to the rapid withdrawal of the webbing and the inertial force (so-called body sensing type) applied to the vehicle body, the rotation of the rotating wheel in the webbing withdrawing direction with respect to the winding shaft ( Relative rotation), whereby the lock plate is moved in a direction intersecting the axis of the winding shaft so that rotation of the winding shaft in the webbing pull-out direction can be prevented.

By the way, in the lock mechanism having such a structure, in order to move the lock plate in a direction intersecting the axis of the winding shaft, as shown in FIG.
It is necessary to dispose the lock plate 80 in the axial direction of the winding shaft 82 (the left-right direction in FIG. 7), and the rock plate rattles in the axial direction of the winding shaft 82 due to the shaking of the vehicle during normal running of the vehicle. There was a problem that occurs. Particularly, in the webbing take-up device for a rear seat in which the take-up shaft 82 is arranged in the vehicle up-down direction, the lock plate 80 can float in the vehicle up-down direction which is the main swing direction of the vehicle during normal running of the vehicle. The lock plate 8
The generation of abnormal noise due to rattling of 0 becomes remarkable.

Therefore, the present applicant has already proposed a lock mechanism for a webbing take-up device capable of greatly reducing the generation of abnormal noise due to rattling of the lock plate (Japanese Utility Model Application Laid-Open No. 1-1).
68354).

In the proposed locking mechanism for a webbing take-up device, as shown in FIG. 6, a rotating piece 84 is formed with a cantilevered arm-shaped flexible piece 86 extending in the circumferential direction. The distal end of the flexible piece 86 protrudes toward the lock plate 80 and is in contact with the surface of the lock plate 80 facing the rotating wheel 84. The flexible piece 86 is thin and elastically deformable and deformable.
To the opposite end surface 82A of the winding shaft 82.

Therefore, the lock plate 80 does not rattle in the axial direction of the winding shaft 82 due to the shaking during running of the vehicle, and there is no generation of abnormal noise due to rattling.

[0008]

However, in the lock mechanism having such a structure, since the lock plate 80 is pressed by the flexible piece 86 formed on the rotating wheel 84, the lock mechanism is wound when the vehicle suddenly decelerates. When the rotation of the rotating wheel 84 with respect to the take-up shaft 82 is delayed, sliding frictional resistance is generated between the rotating wheel 84 and the lock plate 80. Since this sliding frictional resistance affects the rotation delay accuracy of the rotating wheel 84 (that is, the sensing performance of the lock mechanism), it is necessary to strictly control the pressing force of the flexible piece 86 to maintain the predetermined sensing performance. However, there is a disadvantage that it is difficult to select a material and design a shape.

In particular, in a lock mechanism that causes a rotation delay of the rotating wheel due to the inertial force (webbing sensing type) due to the rapid withdrawal of the webbing described above, the rotating wheel is an inertial body, so the sliding friction resistance is reduced. Greatly affects the sensing performance of the lock mechanism.

In consideration of the above facts, the present invention not only can prevent the generation of abnormal noise due to the lock plate, but also can easily select and design a material for maintaining a predetermined sensing performance. The purpose is to get a mechanism.

[0011]

A locking mechanism for a webbing take-up device according to the present invention comprises a metal shaft and a resin adapter integrally fixed to the shaft, and winds the occupant restraining webbing. A winding shaft, a lock plate linked to the winding shaft around the winding shaft and rotated following the winding shaft, and a winding plate linked to the winding shaft so as to overlap the lock plate. A rotating wheel that is rotated following the take-up shaft; and The webbing is drawn out of the winding shaft by moving the lock plate in a direction intersecting the axis of the winding shaft by causing a rotation delay in the webbing withdrawing direction with respect to the winding shaft on the rotating wheel in association with the lock plate. direction In the lock mechanism for a webbing take-up device that prevents rotation of the take-up shaft, a flange portion facing the lock plate is formed on the adapter of the take-up shaft, and the lock plate can float in the axial direction of the take-up shaft by the flange portion. And the contact between the lock plate and the shaft of the winding shaft in the axial direction of the winding shaft is prevented.

[0012]

In the lock mechanism for a webbing take-up device having the above-mentioned structure, the lock plate is held movably in the axial direction of the take-up shaft by a flange portion of a take-up shaft adapter made of resin and made of metal. The contact of the winding shaft with the shaft in the axial direction of the winding shaft is prevented. Therefore, abnormal metal noise due to rattling of the lock plate is prevented.

[0013]

FIG. 3 is an exploded perspective view of a webbing retractor 10 to which a lock mechanism for a webbing retractor according to an embodiment of the present invention is applied.

A pair of legs 14 and 16 extend parallel to each other from both sides of the base of the frame 12 of the webbing take-up device 10.
8 is rotatably supported. As shown in detail in FIGS. 1 and 2, the winding shaft 18 is a metal plate-shaped shaft 20.
And a resin adapter 24 covered with the tip of the shaft 20 and integrally fixed by a stopper 22, and a spool 26 attached around the shaft 20 and the adapter 24 so as to cover them. As a pincushion. One end of an occupant restraining webbing 28 is locked to the winding shaft 18.

One end of the winding shaft 18 protrudes outside the leg portion 14, and the inner end of the mainspring 30 is locked to this protruding portion. The outer end of the mainspring 30 is locked to a spring cover 32 that accommodates the mainspring 30, and the winding shaft 18 is urged and rotated in the direction of arrow A in FIG. The webbing 28 is wound out in layers, and the webbing 28 is pulled out by rotating the winding shaft 18 against the biasing force of the mainspring spring 30.

On the other hand, the other end of the winding shaft 18, that is, the adapter 24, projects outside the leg 16. Adapter 2
A small-diameter shaft portion 34 protrudes coaxially from the end surface 24 </ b> A of the fourth member 4, and a through hole 36 is formed near the base of the small-diameter shaft portion 34. In the middle of the small diameter shaft portion 34, a through hole 3 is provided.
6, a flange portion 38 is integrally formed.
The flange portion 38 includes a lock plate 46 described later,
48. Further, a concave portion 40 and a forked portion 42 are formed at the tip of the shaft 20. The forked portion 42 penetrates through the through hole 36 of the adapter 24 and reaches the flange portion 38.

Around the forked portion 42 of the shaft 20, two lock plates 4 accommodated in the sensor cover 44 are provided.
A lock wheel 50 as a rotating wheel is provided so as to overlap the lock plates 6 and 48 and the lock plates 46 and 48.

Each of the lock plates 46 and 48 has a substantially C-shape having a substantially U-shaped cutout recess 52 formed at the center thereof, and has an end surface 24A of the winding shaft 18 (adapter 24).
4 and 5 are positioned between the shaft and the flange 38 so as to be freely movable in the axial direction of the winding shaft 18 by a small amount.
As shown in FIG. 3, the concave portion 40 of the shaft 20 is located in the cutout concave portion 52 so that the shaft 20 can rotate following the winding shaft 18.

Here, as shown in FIG. 2, the clearance dimension δ ₁ between the end face 24 A of the adapter 24 and the flange portion 38 is
The concave portion 40 of the shaft 20 is formed to be smaller than the width dimension δ ₂ , and the end surface 24A of the adapter 24 and the lower end surface of the flange portion 38 are both located in the concave portion 40 of the shaft 20 (in a state in which the shaft 24 has entered). ), The dimensions of each part are set. Therefore, the lock plates 46 and 48 located between the end surface 24A of the adapter 24 and the flange portion 38 are connected to the adapter 24 (flange portion 38).
, So that it does not come into contact with both axial end surfaces of the concave portion 40 of the shaft 20 or the forked portion 42.

The width of the notch 52 of each of the lock plates 46 and 48 is slightly larger than the thickness of the shaft 20 (recess 40) as shown in FIG. The lock plates 46 and 48 can rotate relative to the winding shaft 18 by a predetermined angle.

Claws 54, 56 are formed at one end of the lock plates 46, 48, respectively, and correspond to the lock teeth of the internal ratchet wheel 58 fixed to the leg 16. Further, a pair of pins 60 and 62 are projected from the lock plates 46 and 48, respectively, and are inserted into long holes 64 formed in the lock wheel 50.

The lock wheel 50 has a boss 66 formed at the center thereof, and the small diameter shaft 34 of the winding shaft 18 is inserted into the boss 66 so as to be rotatable relative to the winding shaft 18. The surface of the lock wheel 50 opposite to the lock plates 46 and 48 is formed in a concave shape, and a ring-shaped mass body 68 is integrally fitted in the concave portion.

The lock ring 50 is prevented from falling out of the small diameter shaft portion 34 by a clip 70 locked at the tip of the small diameter shaft portion 34 of the winding shaft 18. The clip 70 is engaged with the small diameter shaft portion 34 and is rotated integrally with the winding shaft 18. A torsion coil spring 72 is interposed between the clip 70 and the lock wheel 50. The coil portion of the torsion coil spring 72 is fitted to the boss portion 66 of the lock wheel 50, and one hook portion is locked by the clip 70,
The other hook portion is locked to the main body portion of the lock wheel 50, and urges the lock wheel 50 against the clip 70 in the webbing pulling-out direction (the direction opposite to the arrow A in FIGS. 3 to 5).

That is, the torsion coil spring 72 causes the pins 60, 62 of the lock plates 46, 48 to be positioned at one end of the long hole 64 as shown in FIG.
4 and 56 are spaced apart from the internal tooth ratchet wheel 58, and the lock wheel 50 is prevented from further rotating relative to the winding shaft 18 in the webbing pull-out direction. This state of the lock plates 46 and 48 is maintained as long as the lock wheel 50 and the winding shaft 18 do not rotate relative to each other. Further, the winding shaft 18 is opposed to the biasing force of the torsion coil spring 72.
Is rotated relative to the lock wheel 50 in the webbing pull-out direction, the lock wheel 50 causes a rotation delay with respect to the winding shaft 18, and the winding shaft 18 presses the lock plates 46 and 48. As a result, the lock plates 46 and 48 are moved in the longitudinal direction of the long holes 64 by the pins 60 and 62 being guided by the long holes 64, and the claws 54 and 56 are engaged with the internal ratchet wheel 58 as shown in FIG. 5. Configuration.

A pawl 74 is disposed below the lock wheel 50. One end of the pawl 74 is pivotally supported by a sensor bracket 76 fixed to the leg 16, and a sensor ball 78 having an intermediate portion disposed in a small-diameter hole of the sensor bracket 76.
The tip of the other end corresponds to a ratchet tooth formed on the outer peripheral portion of the lock ring 50.

The pawl 74 is pressed by a sensor ball 78 rising from the inside of the small diameter hole of the sensor bracket 76 to the outside thereof by inertia force due to rapid deceleration of the vehicle, and is rocked. The locking wheel 50 is prevented from rotating in the webbing pull-out direction by engaging with the ratchet teeth.

In the webbing retractor 10 configured as described above, the frame 12 is attached to the vehicle body via bolts. When the webbing take-up device 10 is used in a three-point seat belt device of a continuous webbing type, the webbing 28 pulled out from the take-up shaft 18 has its end locked to the vehicle body via an anchor member. The intermediate portion is folded back by a slip joint fixed to the vehicle body, and a tongue plate is slidably mounted in a longitudinal direction at an intermediate portion between the anchor member and the slip joint. Then, the occupant seated on the seat takes up the webbing 28 on the winding shaft 1.
By pulling the tongue plate out of the tongue 8 and engaging the tongue plate with a buckle device attached to the vehicle body, the occupant is brought into a webbing mounted state.

Next, the operation of this embodiment will be described. In a normal running state of the vehicle, the webbing 28 is freely pulled out from the winding shaft 18 and wound on the winding shaft 18 following the change in the body posture of the occupant wearing the webbing 28, thereby restraining the occupant. Never do. That is, in the normal rotation of the winding shaft 18, the torsion coil spring 72 is not deformed, and no relative rotation occurs between the winding shaft 18 and the lock wheel 50.

Here, lock plates 46, 48 located between the end face 24A of the adapter 24 and the flange portion 38 are provided.
Are held only by the adapter 24 (flange portion 38) and are made of metal lock plates 46 and 48.
Are the two axial end faces of the concave portion 40 of the shaft 20 and the forked portion 4.
2 does not come into contact with the vehicle 2 and the occurrence of metallic noise due to the vibration of the vehicle is prevented.

When the occupant wearing the webbing 28 suddenly changes his body posture and the webbing 28 is suddenly pulled out from the winding shaft 18, the winding shaft 18 is rapidly rotated. For this reason, a large force acts on the torsion coil spring 72 momentarily due to the inertial force of the lock wheel 50 (the mass body 68), and the torsion coil spring 72 is deformed against the urging force. , A rotation delay occurs in the lock wheel 50. Due to the relative rotation of the winding shaft 18 and the lock wheel 50, the lock plates 46 and 48 are pressed and moved by the winding shaft 18, and the claws 54 and 56 mesh with the internal ratchet wheel 58 as shown in FIG. The rotation of the winding shaft 18 in the webbing withdrawing direction is prevented. Accordingly, the occupant is restrained by the webbing 28.

When the vehicle is suddenly decelerated, the pawl 74 is swung by the sensor ball 78 which rises from the inside of the small diameter hole of the sensor bracket 76 to the outside due to the inertial force, and the pawl 74 swings to engage the lock wheel 50. In addition, the lock wheel 50 is prevented from rotating in the webbing pull-out direction. As a result, the rotation of the lock wheel 50 is delayed with respect to the winding shaft 18, which is pulled out and rotated by the inertia force of the occupant due to the rapid deceleration of the vehicle, as described above. 46 and 48 are moved and mesh with the internal ratchet wheel 58, so that the webbing 28 is prevented from being pulled out, and the occupant is restrained by the webbing 28.

Here, lock plates 46, 48 located between the end face 24A of the adapter 24 and the flange portion 38.
Is simply held by the adapter 24 (flange portion 38), and is not a structure in which the lock plates 46 and 48 are pressed by a flexible piece or the like formed on the lock ring 50 to prevent backlash as in the related art. In addition, when the lock wheel 50 has a rotation delay with respect to the winding shaft 18, sliding friction resistance does not occur. Therefore, there is no adverse effect on the rotation delay accuracy of the lock wheel 50 (the sensing performance of the lock mechanism), and it is not necessary to strictly control the pressing force and to select a material for maintaining the predetermined sensing performance, and to design the shape. It will be easier.

[0033]

As described above, the lock mechanism for the webbing take-up device according to the present invention can not only prevent the generation of abnormal noise due to the lock plate but also select a material for maintaining a predetermined sensing performance. This has an excellent effect that the design becomes easy.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part of a webbing take-up device to which a lock mechanism according to an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view of a main part of the webbing take-up device to which the lock mechanism according to the embodiment of the present invention is applied.

FIG. 3 is an exploded perspective view of the webbing retractor to which the lock mechanism according to the embodiment of the present invention is applied.

FIG. 4 is a front view showing an arrangement state of a lock plate of the webbing take-up device shown in FIG. 3;

FIG. 5 is a front view showing an operation state of the lock plate shown in FIG. 4;

FIG. 6 is a cross-sectional view showing a structure around a lock plate of a webbing take-up device to which a conventional lock mechanism is applied.

FIG. 7 is a cross-sectional view showing a structure around a lock plate of a webbing take-up device to which a conventional lock mechanism is applied.

[Explanation of symbols]

 Reference Signs List 10 webbing take-up device 18 take-up shaft 20 shaft 24 adapter 38 flange portion 46 lock plate 48 lock plate 50 lock wheel (rotating wheel)

Claims (1)

(57) [Claims] 1. A winding shaft, comprising a metal shaft and a resin adapter integrally fixed to the shaft, for winding a webbing for restraining an occupant, and cooperating with the winding shaft around the winding shaft. A lock plate that is rotated to follow the take-up shaft, and a rotating wheel that is linked to the take-up shaft so as to overlap the lock plate and is rotated to follow the take-up shaft, The lock plate is movably arranged in the axial direction of the winding shaft so as to be able to move in the direction intersecting with the axis of the winding shaft, and the rotating wheel is also linked to the lock plate so that the rotating wheel is webbed with respect to the winding shaft. In a lock mechanism for a webbing take-up device, which causes a rotation delay in a pull-out direction to move a lock plate in a direction intersecting an axis of a take-up shaft to prevent rotation of the take-up shaft in a webbing pull-out direction, Previous A flange portion facing the lock plate is formed on an adapter of the winding shaft, and the flange portion holds the lock plate movably in the axial direction of the winding shaft. A lock mechanism for a webbing take-up device, wherein contact of the take-up shaft in the axial direction is prevented.