JPH0514930Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is used for a webbing retractor that winds and stores occupant restraint webbing in layers.
In particular, the present invention relates to a webbing retractor that can control the retracting force when an occupant wears webbing.

[Prior Art] A winding device installed in a vehicle is capable of winding webbing in layers onto a winding shaft. That is, one end of a mainspring spring is locked to the winding shaft, and the winding shaft is biased and rotated by the biasing force of the mainspring spring. Therefore, when the webbing is released, the webbing can be quickly wound onto the take-up shaft and stored. However, the biasing force of the mainspring spring acts even when the webbing is attached, which may give the occupant a feeling of pressure.

In order to solve this problem, a structure has been proposed that prevents the rotational biasing force in the webbing winding direction of the winding shaft when the occupant is wearing the webbing (for example,
No. 15861).

When a predetermined amount of webbing is taken up and pulled out after the webbing is pulled out, the pawl lever, which is controlled by a cam mechanism, is engaged with a ratchet that rotates together with the take-up shaft, thereby preventing the take-up shaft from rotating in the webbing take-up direction. It's becoming like that.

However, in such a structure, if the take-up device is equipped with a lock mechanism (referred to as WSIR) that prevents the take-up shaft from rotating in the webbing pull-out direction in response to sudden webbing pull-out, the pawl lever and ratchet This mechanism was activated by the impact upon engagement, and the webbing drawer was sometimes locked. In this case, the pawl is engaged with the ratchet, so it is impossible to wind up the webbing.

[Problems to be solved by the invention] Taking the above facts into consideration, the present invention provides a webbing winding method that does not apply an excessive impact force to the take-up shaft when the rotation of the take-up shaft in the webbing winding direction is prevented. The purpose is to obtain a device for

[Means for Solving the Problems] The webbing retractor according to the present invention is a webbing retractor equipped with a lock mechanism that can instantly prevent rotation of the retracting shaft in the webbing retracting direction in response to sudden webbing retraction. The winding device includes a ratchet arranged to be rotatable together with the winding shaft, and a state in which the ratchet is engaged with the ratchet at a predetermined position and a state in which it is disengaged from this state between the ratchet and the winding shaft. When engaged at the predetermined position, the rotational force of the winding shaft is transmitted to the ratchet, and when disengaged from the ratchet, the ratchet and winding shaft are moved relative to each other. a rotational force transmission member that is rotatable; and the rotational force transmission member is biased and held in a state of engagement with the ratchet at a predetermined position, and an impact force of a predetermined value or more is applied to the rotational force transmission member. In some cases, a buffer member that enables movement of the rotational force transmitting member to a state separated from the ratchet;
a pawl disposed so as to be able to engage and separate from the ratchet, and to prevent rotation of the ratchet in the webbing winding direction when engaged with the ratchet; and a pawl that moves the pawl to the ratchet when the webbing is pulled out by a predetermined amount from the winding shaft. It is characterized by having a control means for engaging.

[Function] In the webbing take-up device with the above configuration, normally,
The rotational force transmitting member is held in engagement with the ratchet by the buffer member, and the rotational force of the winding shaft is transmitted to the ratchet, so that the ratchet rotates integrally with the winding shaft.

When the webbing is pulled out a predetermined amount and the pawl is engaged with the ratchet by the control means, if the impact force at this engagement exceeds a predetermined value, the rotational force transmission member is released from being held by the buffer member and rotates. The force transmitting member can be moved away from the ratchet, so that the winding shaft can rotate relative to the ratchet. Therefore, the impact force when the pawl engages with the ratchet is relaxed and does not act on the take-up shaft, and the locking mechanism (WSIR) will not operate unless the webbing is suddenly pulled out.

[Example] FIG. 1 shows a webbing take-up device 10 according to this example.

The frame 12 made of a steel plate is bent at both ends in the width direction parallel to each other to form leg plates 12A and 12B. Coaxial circular holes 14, 14 are provided in the leg plates 12A, 12B, and the winding shaft 16
is being passed over.

A slit hole (not shown) is provided in the longitudinally intermediate portion of the winding shaft 16, and one end of the webbing 20 is locked therein so that the webbing 20 can be wound around the winding shaft 16 in layers.

A slit groove 18 is formed at one end of the winding shaft 16 (on the side of the leg plate 12B), and the inner end of the mainspring spring 22 is locked therein. The outer end of the mainspring spring 22 is connected to a notch 2 formed in the spring cover 24.
6, whereby the take-up shaft 16 is biased in the direction of winding up the webbing 20 (in the direction of arrow A in FIG. 1). Therefore, when the occupant releases the webbing 20, the webbing 20 can be quickly wound up and stored.

The webbing take-up device 10 is equipped with a so-called WSIR (webbing sensitive sensor) that prevents the take-up shaft 16 from rotating in the webbing pull-out direction (in the direction opposite to the arrow A direction in FIG. 1) in response to sudden pull-out of the webbing 20. Inashiya reel) is attached (not shown). Thereby, when tension is applied to the webbing 20 due to the inertia of the occupant when the occupant is wearing the webbing, rotation of the take-up shaft 16 in the webbing take-up direction is prevented, and the occupant can be reliably restrained.

As shown in FIG. 2, a recess 28 is formed at the other end of the winding shaft 16 in a direction perpendicular to the axis. Also, a ratchet 3 is attached to the end of the winding shaft 16.
4 is pivoted. A circular hole 36 is formed in the center of the ratchet 34, into which the end of the winding shaft 16 is inserted.

A compression coil spring 30 as a buffer member is arranged in a compressed state in the recess 28 of the winding shaft 16, and steel balls 32 as rotational force transmitting members are wound around both ends of the compression coil spring 30. It is arranged so as to protrude from the periphery of the shaft 16. Also, the circular hole 3 of the ratchet 34
An engaging portion 38 having an arcuate cross-sectional shape and a size corresponding to the steel ball 32 is continuously formed on the inner circumferential wall of the ball 6 over the entire circumference. Therefore, under normal conditions, the steel ball 32 is fitted into the engaging portion 38 by the biasing force of the compression coil spring 30, and the winding shaft 16 and the ratchet 34 rotate integrally. When rotation in the webbing take-up direction is blocked and a rotational force of a predetermined value or more is applied to the take-up shaft 16, the compression coil spring 30 is further compressed and the steel ball 32 is compressed as shown in FIG.
comes out of the engaging portion 38, and the winding shaft 16 becomes rotatable relative to the ratchet 34, and this rotation causes the steel ball 32 to fit into the adjacent engaging portion 38 again. .

Teeth 40 formed on the outer periphery of the ratchet 34 correspond to claws 42A formed at one end of the pawl 42.

The other end of the pawl 42 is pivotally supported on a support pin 46 of a cam cover 44.
By rotating in the direction of arrow B in FIG. 5A around , the pawl portion 42A engages with the tooth portion 40 of the ratchet 34. Further, after the claw portion 42A engages with the tooth portion 40, rotation of the ratchet 34 in the webbing winding direction is prevented by the pawl 42. Ratchet 34 and cam cover 4
A cam plate 48 serving as a control means is disposed between the cam plate 4 and the cam plate 4 .

The cam plate 48 is provided with a circular groove 50 in its center, and is configured to rotate under the rotational force of the ratchet 34 with a predetermined frictional force. A rib 52 is provided in an arc shape in the vicinity of the outer periphery of the cam plate 48, and an inner cam groove 54 and an outer cam groove 56 are provided on the inside and outside of the rib 52, respectively. This inner cam groove 54,
A pin 58 formed on the pawl 42 is inserted into the outer cam groove 56.

The pin 58 is moved toward the rib 52 by the rotation of the cam plate 48 in response to the rotation of the take-up shaft 16 in the webbing take-up direction.
The webbing enters a substantially U-shaped guide groove 60 formed near one end 52A of the winding shaft 16, and then, when the winding shaft 16 rotates in the webbing pull-out direction by a predetermined amount or more (approximately one rotation in this embodiment), the webbing passes through the inner cam groove 54 and exits from the other end 52B into the outer cam groove 56 (see Figures 5A to 5C).

Here, the other end portion 52B of the rib 52 is elastically deformable in the direction of expanding or contracting the width of the inner cam groove 54, and the pin 58 is moved from the inner cam groove 54 to the outer cam groove 52B.
6, the inner cam groove 54 is elastically deformed by the pressing force of the pin 58 to expand the diameter of the inner cam groove 54, and the pin 58 reaches the side surface of the convex portion 48A of the cam plate 48 and closes the end of the inner cam groove 54 again. (Fig. 5 C)
reference).

Therefore, when this pin 58 moves in the opposite direction (rotation of the cam plate in the webbing winding direction), the other end 52B of this rib 52 moves between the inner cam groove 54 and the outer cam groove, as shown in FIG. 5D. 56, so that the pin 58 is guided to the outer cam groove 56.

That is, this pin 58 moves from the webbing storage state to the guide groove 60 in a trajectory indicated by arrow C in FIG. 5A by rotating the take-up shaft 16 one or more rotations in each of the webbing winding direction and the webbing pulling-out direction, starting from the guide groove 60. It's becoming like that.

Further, a recess 62 is formed in a part of the side surface of the inner cam groove 54, and only when the pin 58 enters the recess 62, the claw 42A and the tooth 40 of the ratchet 34 engage. (See Figure 5E).

Furthermore, when the take-up shaft 16 rotates in the direction in which the webbing 20 is pulled out, the take-up shaft 16, the ratchet 34, and the cam plate 48 rotate integrally, and the pin 5
8 moves within the inner cam groove 54, so when the rotation in the pull-out direction is stopped and the webbing 20 is wound up by the biasing force of the mainspring spring 21, the claw portion 42
A is adapted to re-engage the same tooth 40 of the ratchet 34 with which it was currently engaged.

The operation of this embodiment will be explained below.

When the webbing 20 is almost completely wound onto the take-up shaft 16, the pin 58 is attached to the rib 52.
It is held in a guide groove 60 near one end 52A (see FIG. 5A).

Here, when the passenger pulls out the webbing 20,
In response, the cam plate 48 rotates together with the winding shaft 16, and the pin 58 is guided by the inner cam groove 54 (see FIG. 5B) and reaches the other end 52B of the rib 52.
The other end 52B of the rib 52 is elastically deformed by the pressing force of the pin 58 and comes out of the inner cam groove 54.

The pin 58 comes into contact with the side surface of the convex portion 48A (see FIG. 5C), and this pin 58 acts as a stopper, stopping the rotation of the cam plate 48 and allowing it to rotate relative to the winding shaft 16.

Here, when the passenger puts on the webbing 20, he or she usually pulls it out a little longer. Therefore, the webbing 20 that has been pulled out in excess is wound onto the take-up shaft 16 by the biasing force of the mainspring spring 22.

This rotation of the take-up shaft 16 in the webbing take-up direction causes the pin 58 to move into the outer cam groove 5.
(see FIG. 5D), reaches one end 52A of the rib 52, and is held in the guide groove 60.

In this state, when the occupant slightly pulls out the webbing 20 with his or her abdomen, the pin 58 enters the recess 62 of the inner cam groove 54 (see FIG. 5E), and the claw 42A of the pawl 42 engages with the tooth 40 of the ratchet 34. will be combined.

As a result, rotation of the take-up shaft 16 in the webbing take-up direction is prevented and the biasing force of the mainspring spring 22 is not transmitted to the webbing 20, so that the occupant does not feel pressured even when wearing the webbing.

Also, when this webbing is attached, the winding shaft 1
6 for preventing rotation in the webbing winding direction, that is, the claw portion 4
2A and the teeth 40, the webbing 20 is engaged with the cam plate 48 and the ratchet 34 while the webbing 20 is within one rotation of the take-up shaft 16, that is, while the pin 58 is disposed within the inner cam groove 54. Since the webbing 20 rotates integrally with the webbing 20, the webbing 20 is pulled out when the occupant moves his or her upper body, and then the pulling out is stopped and the webbing 20 is wound up by the biasing force of the mainspring spring 22. Even the claw part 42
A is re-engaged with the same teeth 40 of the ratchet 34 with which it was currently engaged, and the length of the webbing 20 pulled out is not changed.

In this case, the ratchet 34 and the pawl 4
2, in the conventional structure, the impact force due to this engagement is transmitted to the WSIR through the winding shaft 16, and this
Since the WSIR is activated and the ratchet 34 is engaged with the pawl 42, the take-up shaft 16 sometimes becomes unable to rotate in both the webbing pull-out direction and the webbing take-up direction.

However, in this embodiment, a steel ball 32 biased by a compression coil spring 30 is interposed between the ratchet 34 and the winding shaft 16, and normally this steel ball 32 is attached to the engaging portion 38 of the ratchet 34. The winding shaft 16 and the ratchet 34 are fitted into the winding shaft 16 so that they rotate together, but when an impact force of a predetermined value or more, that is, a rotational force is applied to the winding shaft 16, the compression coil spring 30 contracts and expands. By absorbing the impact force, the steel ball 32 comes out of the engaging portion 38, and the winding shaft 16 begins to rotate relative to the ratchet 34. Therefore, the impact force generated when the ratchet 34 and the pawl 42 engage is alleviated, the WSIR is not activated, and the webbing 20 is not prevented from being pulled out except in a vehicle emergency.

Furthermore, if the vehicle is in an emergency situation and tension is applied to the webbing 20 due to the inertia of the occupant, the take-up device 10 is equipped with a WSIR, so the rotation of the take-up shaft 16 in the webbing pull-out direction is instantaneous. This makes it possible to securely restrain the occupants.

When the occupant releases the webbing, the pin 58 comes out of the inner cam groove 54 by pulling out the webbing 20 by one rotation or more of the take-up shaft 16, and the webbing 20 is wound onto the take-up shaft 16 in layers. , can be accommodated. At this point, the pin 58 is placed in the guide groove 60, the cam plate 48 and the take-up shaft 16 rotate relative to each other, and the webbing is ready for the next webbing installation.

As described above, in the present invention, the winding force blocking structure when the webbing is attached can be constructed with a simple structure, so that the shape of the winding device itself becomes compact and the assembly workability is improved.

Although the steel ball 32 is used as the rotational force transmitting member in this embodiment, the present invention is not limited to this, and a substantially cylindrical transmitting member 64 having a hemispherical end may be used as shown in FIG. In this case, the rotational force of the winding shaft 16 can be applied to the ratchet 34 even more reliably.
can be transmitted to.

[Effects of the invention] As explained above, the webbing retractor according to the present invention is a webbing retractor equipped with a lock mechanism that can instantly prevent the rotation of the take-up shaft in the webbing withdrawal direction in response to sudden webbing withdrawal. The take-up device includes a ratchet rotatably arranged together with the take-up shaft, and a state in which the ratchet is engaged with the ratchet at a predetermined position and a state in which it is disengaged from this state, between the ratchet and the take-up shaft. and transmitting the rotational force of the winding shaft to the ratchet when engaged at the predetermined position;
and a rotational force transmission member that allows relative rotation between the ratchet and the winding shaft when the winding shaft is detached from the ratchet, and a rotational force transmission member that is biased to maintain the rotational force transmission member engaged with the ratchet at a predetermined position. At the same time, when an impact force of a predetermined value or more is applied to the rotational force transmission member, a buffer member is engaged with the ratchet, which enables the rotational force transmission member to move to a state separated from the ratchet. a pawl that is arranged so as to be able to separate from the pawl and prevents the ratchet from rotating in the webbing winding direction when engaged with the ratchet; and a control means that engages the pawl with the ratchet when the webbing is pulled out by a predetermined amount from the take-up shaft. Since it is characterized by having the following, when the rotation of the take-up shaft in the webbing winding direction is prevented, no more than necessary impact force is applied to the take-up shaft, and the lock mechanism is thereby activated. It has the excellent effect of not causing any damage.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a webbing retractor according to an embodiment of the present invention, FIG. 2 is a perspective view of the main parts of FIG. 1,
Figure 3 is a sectional view taken along the - line in Figure 1;
The figure is a sectional view taken along the - line in Figure 3, and Figure 5A.
7E to E are operation explanatory views showing the state of engagement between the ratchet and the pawl, and FIG. 6 is a perspective view showing another embodiment. DESCRIPTION OF SYMBOLS 10... Webbing winding device, 16... Winding shaft, 20... Webbing, 30... Compression coil spring, 32... Steel ball, 34... Ratchet, 42... Paul, 48... Cam plate.

Claims (1)

[Claims for Utility Model Registration] (1) A webbing retractor equipped with a lock mechanism that can instantly prevent the rotation of a take-up shaft in the webbing withdrawal direction in response to sudden withdrawal of the webbing, which a ratchet disposed rotatably together with the take-up shaft; a ratchet disposed between the ratchet and the take-up shaft so as to be movable between a state in which it is engaged with the ratchet at a predetermined position and a state in which it is disengaged from this state; When engaged at the predetermined position, the rotational force of the winding shaft is transmitted to the ratchet, and
a rotational force transmission member that allows the ratchet and the winding shaft to rotate relative to each other when the winding shaft is detached from the ratchet; and a rotational force transmission member that biases the rotational force transmission member to maintain engagement with the ratchet at a predetermined position. a buffer member that enables the rotational force transmission member to move to a state separated from the ratchet when an impact force of a predetermined value or more is applied to the rotational force transmission member; and a buffer member capable of engaging and separating from the ratchet. placed in
The pawl includes a pawl that prevents the ratchet from rotating in the webbing winding direction when engaged with the ratchet, and a control means that engages the pawl with the ratchet when the webbing is pulled out by a predetermined amount from the take-up shaft. Characteristic webbing retractor. (2) Utility model registration claim (1) characterized in that the rotational force transmitting member is a sphere and is fitted into an engaging portion formed on the ratchet to transmit the rotation of the winding shaft to the ratchet. The webbing retractor described in . (3) Utility model registration claim No. (1) characterized in that the buffer member is a compression coil spring.
or (2).