JP4608812B2 - Seat belt through anchor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a through anchor through which a webbing of a seat belt device is passed.
[0002]
[Prior art]
In the seat belt device, the webbing drawn out from the retractor is passed through the through anchor and is drawn around the front side of the occupant. The retractor includes a spring that pulls the webbing in the winding direction, and a force in the take-up direction is always applied to the webbing.
[0003]
When pulling out the webbing and when winding the webbing around the retractor, the friction force of the through anchor is applied to the webbing. In order to reduce the frictional force so that the webbing can be smoothly wound and pulled out, there is known a structure in which a rotatable roller is provided on the through anchor and the webbing is applied to the roller.
[0004]
By the way, a pretensioner mechanism and an EA mechanism may be incorporated in the retractor. The pretensioner mechanism is used to wind up the webbing for a predetermined length in an emergency such as a car collision, and to firmly restrain the occupant to the seat. The EA mechanism is for absorbing the impact applied to the occupant by gradually feeding the webbing from the retractor when a load is applied from the occupant to the webbing after the webbing is wound up by the pretensioner mechanism.
[0005]
[Problems to be solved by the invention]
As described above, if a roller is provided in the through anchor, the webbing can be sufficiently wound even if the webbing winding force by the pretensioner mechanism is reduced. However, if this roller is provided in the through anchor, when the occupant's load is applied to the webbing after being wound by a predetermined length by the pretensioner mechanism, this load is almost not affected by the friction force of the through anchor. It will be added to the EA mechanism as it is, and it will be necessary to use an EA mechanism that can bear a large load, increasing the price or weight of the EA mechanism.
[0006]
It is an object of the present invention to provide a through anchor for a seat belt in which the friction of the webbing is small when the webbing is wound by the pretensioner mechanism, and a large frictional force is applied to the webbing when the EA mechanism is operated.
[0007]
[Means for Solving the Problems]
The through anchor of the seat belt according to the present invention is a through anchor of a seat belt having a hanging shaft on which a webbing pulled out from a retractor is hung and an anchor base that supports both ends of the hanging shaft. In a direction in which the webbing is taken up by the retractor when a predetermined pressing force is applied to the cylinder from the webbing. A through anchor for a seat belt having a one-way mechanism that allows rotation of the cylinder and prevents rotation of the cylinder in a direction in which the webbing is pulled out of the retractor , the one-way mechanism including an outer peripheral surface of the shaft and Saw-tooth portions respectively provided on the inner peripheral surface of the cylinder, and the cylinder so that the saw-tooth portions of the cylinder are separated from the saw-tooth portions of the shaft A support member supported by the shaft, and the support member is deformed or broken when a predetermined pressing force is applied from the webbing to the cylindrical body, and the sawtooth portion of the cylindrical body and the The shaft is engaged with a sawtooth portion of the shaft, and when the teeth are engaged, the cylindrical body is allowed to rotate in the direction in which the webbing is pulled out by the retractor, and the webbing is pulled out from the retractor. It has a tooth shape that prevents the rotation of the cylindrical body .
[0008]
It should be noted that in this through anchor of the seat belt, the cylinder can be rotated both in the webbing pull-out direction and the webbing pull-out direction during normal times (when the automobile has not encountered an emergency such as a collision). Alternatively, the rotation may be restricted in either direction or in either direction.
[0009]
In such a through anchor of the seat belt, when the pretensioner mechanism is activated due to the collision of the automobile, a predetermined pressing force is applied from the webbing to the cylindrical body, and the one-way mechanism acts. In this case, the one-way mechanism allows the cylinder to rotate in the direction in which the webbing is taken up by the retractor. Therefore, when the webbing is taken up by the retractor by the pretensioner mechanism, the cylinder rotates in the take-up direction accordingly. For this reason, the friction generated between the webbing and the cylindrical body is extremely small, the webbing is smoothly taken up by the retractor, and the webbing is sufficiently pretensioned.
[0010]
Thereafter, when the EA mechanism is operated and the webbing is pulled out from the retractor, the one-way mechanism prevents the cylinder from attempting to rotate in the webbing pull-out direction. Thus, since a cylinder does not rotate, a big friction arises between webbing and a cylinder. Accordingly, the pulling force applied from the webbing to the EA mechanism of the retractor is reduced, the load-bearing requirement characteristics of the EA mechanism are alleviated, and the EA mechanism can be reduced in weight or made inexpensive.
[0011]
In the present invention, the one-way mechanism includes sawtooth portions provided on the outer peripheral surface of the shaft and the inner peripheral surface of the cylinder, and the cylinder so that the sawtooth portion of the cylinder is separated from the sawtooth portion of the shaft. A support member supported by the shaft, and the support member is deformed or broken when a predetermined pressing force is applied from the webbing to the cylinder, and the sawtooth portion of the cylinder and the shaft The saw-tooth part engages with the saw-tooth part, and when the saw-tooth part engages, the cylinder allows rotation of the cylinder in the direction in which the webbing is pulled out by the retractor, and the cylinder in the direction in which the webbing is pulled out from the retractor. that it has a tooth shape to prevent rotation of the body.
[0012]
In the through anchor of the seat belt of the present invention having the one-way mechanism having such a configuration, the webbing slides on the outer peripheral surface of the cylindrical body and is normally wound and pulled out.
[0013]
When the pretensioner mechanism is activated due to the collision of an automobile, a pressing force exceeding a predetermined value is applied from the webbing to the cylinder, and the support member is deformed or broken to engage the saw blade of the cylinder and the saw blade of the shaft. To do. In this case, the sawtooth portion allows the cylinder to rotate in the direction in which the webbing is taken up by the retractor. Therefore, when the webbing is taken up by the retractor by the pretensioner mechanism, the cylinder rotates in this take-up direction. For this reason, the friction generated between the webbing and the cylindrical body is extremely small, the webbing is smoothly taken up by the retractor, and the webbing is sufficiently pretensioned.
[0014]
Thereafter, when the EA mechanism is operated and the webbing is pulled out from the retractor, the saw-tooth portion prevents the cylindrical body from rotating in the webbing pull-out direction. Thus, since a cylinder does not rotate, a big friction arises between webbing and a cylinder. Accordingly, the pulling force applied from the webbing to the EA mechanism of the retractor is reduced, the load-bearing requirement characteristics of the EA mechanism are alleviated, and the EA mechanism can be reduced in weight or made inexpensive.
[0015]
When the one-way mechanism has such a configuration, the cylindrical support member is formed of a shear pin, and when the pressing force exceeding the predetermined value is applied to the cylindrical body, the saw-tooth portions are engaged by shearing. It may be allowed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional front view of a through anchor of a seat belt according to an embodiment of the present invention. FIG. 2 (a) is a sectional view taken along the line II-II in FIG. ) Is a cross-sectional view of the same part as FIG. 2A when the pre-tensioner mechanism of the through anchor is operated, and FIG. 3 is an overall view showing an example of a seat belt device provided with the through anchor. In the present embodiment, this seat belt device is applied as an automobile occupant protection device.
[0017]
The webbing 1 of the seat belt device is connected to a retractor 2 so that one end can be wound and unwound, and the other end is fixed to the vehicle body by an anchor 3. The webbing 1 is routed through the through anchor 4 and the tongue 5 respectively.
[0018]
Although not shown, the retractor 2 includes a return spring that pulls the webbing 1 in the winding direction, whereby a force in the winding direction is always applied to the webbing 1. Further, the retractor 2 winds the webbing 1 by a predetermined length in an emergency such as a vehicle collision, and after winding the webbing 1 by this pretensioner mechanism, An EA mechanism is provided that gradually sends out the webbing 1 when a load is applied to the webbing 1 from an occupant and absorbs an impact applied to the occupant.
[0019]
The through anchor 4 includes a hanging shaft 40 on which the webbing 1 is hung and an anchor base 50 that supports the hanging shaft 40. The hanging shaft 40 is composed of a shaft 42 installed between a pair of convex portions 54, 54 projecting forward from the lower portion of the anchor base 50, and a cylindrical body 44 externally fitted to the shaft 42. The shaft 42 is fixed to the anchor base 50 by a fixing pin 56 so as not to rotate about the axis. The through anchor 4 is connected to the vehicle body by a connecting means such as a bolt (not shown) through an upper hole 52 of the anchor base 50.
[0020]
On the outer peripheral surface of the shaft 42 and the inner peripheral surface of the cylindrical body 44, sawtooth portions 46 and 48 that can be engaged with each other are provided. When these saw-tooth portions 46 and 48 are engaged with each other, rotation of the cylindrical body 44 in the direction in which the webbing 1 is wound around the retractor 2 (hereinafter, rotation in this direction is referred to as “forward rotation”). One way to prevent the rotation of the cylindrical body 44 in the direction in which the webbing 1 is pulled out from the retractor 2 (hereinafter, the rotation in this direction may be referred to as “rotation in the reverse direction”). It has the tooth shape which comprises a mechanism. The inner diameter of the cylindrical body 44 is larger than the outer diameter of the shaft 42. When the shaft 42 and the cylindrical body 44 are arranged coaxially, the sawtooth portion 46 and the sawtooth portion 48 are separated from each other, They are not engaged with each other.
[0021]
As shown in FIG. 2 (a), the cylindrical body 44 is supported substantially coaxially so that the sawtooth portions 46 and 48 are separated from each other by a shear pin 60 passing through the cylindrical body 44 and the shaft 42. It is fixed to the shaft 42 so as not to rotate around the shaft. The shear pin 60 is broken when a predetermined pressing force is applied to the cylindrical body 44 from the webbing 1 provided on the cylindrical body 44. When the pin 60 is broken, the support of the cylindrical body 44 and the fixing to the shaft 42 are released, and the sawtooth portion 46 on the inner peripheral surface of the cylindrical body 44 and the sawtooth portion 48 of the shaft 42 are engaged.
[0022]
In the seat belt device including the through anchor 4 configured as described above, the webbing 1 drawn from the retractor 2 is hung on the hanging shaft 40 along the outer peripheral surface of the cylindrical body 44.
[0023]
When wearing the webbing 1 in a normal state, the occupant pulls the webbing 1 from the retractor 2 and draws it toward the front side of the body. Next, the tongue plate 5a of the tongue 5 attached in the middle of the webbing 1 is inserted into the buckle 7, and the mounting of the webbing 1 is completed. Conversely, when releasing the webbing 1, the release button 7 a of the buckle 7 is operated to remove the tongue 5 from the buckle 7, and the webbing 1 is wound up by the winding force of the retractor 2. It should be noted that since the cylindrical body 44 is normally unable to rotate in the forward / reverse direction, the webbing 1 is used for both the case where the webbing 1 is pulled out and the case where the webbing 1 is wound around the retractor 2. It slides along the outer peripheral surface of 44.
[0024]
When the vehicle collides with the webbing 1 mounted on the occupant, the pretensioner mechanism of the retractor 2 is activated, and the retractor 2 rapidly winds the webbing 1 by a predetermined length so that the webbing 1 firmly holds the occupant to the seat To come. At this time, due to the rapid winding of the webbing 1 by the pretensioner mechanism, a predetermined pressing force or more is applied from the webbing 1 to the cylinder 44, the shear pin 60 is broken, and the sawtooth portion 46 of the shaft 42 and the cylinder 44 sawtooth portions 48 engage. In this case, the sawtooth portions 46 and 48 allow the cylindrical body 44 to rotate in the direction in which the webbing 1 is taken up by the retractor 2. Therefore, when the webbing 1 is taken up by the retractor 2 by the pretensioner mechanism, The body 44 rotates in this take-up direction (forward direction). For this reason, the friction generated between the webbing 1 and the cylindrical body 44 is extremely small, and the webbing 1 is smoothly taken up by the retractor 2, and the webbing 1 is sufficiently pretensioned.
[0025]
Thereafter, when the EA mechanism is operated and the webbing is gradually pulled out from the retractor 2, the sawtooth portions 46 and 48 prevent the cylindrical body 44 from rotating (reversely rotating) in the drawing direction of the webbing 1. . Since the cylindrical body 44 does not rotate in this way, a large friction is generated between the webbing 1 and the cylindrical body 44. Accordingly, the pulling force applied from the webbing 1 to the EA mechanism of the retractor 2 is reduced.
[0026]
As described above, in the seat belt device according to this embodiment, the webbing 1 is wound up very smoothly when the pretensioner mechanism is operated, so that the pretensioner mechanism having a small winding force is sufficient. Further, since the load applied to the EA mechanism when the EA mechanism is activated is small, the load-bearing requirement characteristics of the EA mechanism are alleviated, and the EA mechanism can be reduced in weight or made inexpensive.
[0027]
In the present invention, various EA mechanisms can be used. For example, a torsion bar provided so as to rotate together with a webbing take-up spool of a retractor, and a lock mechanism that locks the torsion bar at the time of a vehicle collision or the like and prevents rotation of the spool in the webbing pull-out direction. An example is given. When a torque exceeding a predetermined value is applied to the locked torsion bar, the torsion bar is gradually twisted and the webbing is pulled out little by little, and an EA (impact absorption) operation is performed. When the present invention is applied to a seat belt device employing such a torsion bar type retractor, the force applied to the torsion bar at the time of a vehicle collision is small, so a torsion bar having a small diameter and a light weight can be used. Cost reduction is also realized.
[0028]
In this embodiment, the cylindrical body externally fitted to the shaft is supported with respect to the shaft, and when a predetermined pressing force is applied to the cylindrical body from the webbing, it is broken and the cylindrical sawtooth portion and the shaft As a cylinder support member that allows engagement with the sawtooth portion of the above, a shear pin that shears with a pressing force of a predetermined value or more is used, but the structure of the cylinder support member is not limited to this, for example, Various support members such as a plate-like member that splits with a pressing force of a predetermined level or a member that deforms with a pressing force of a predetermined level or more can be used.
[0029]
In this embodiment, the cylinder is normally fixed to the shaft so as not to rotate around the shaft by the shear pin, and the webbing winding and unwinding from the retractor slides on the outer peripheral surface of the cylinder. that has become to be done by.
[0030]
4 is a partial cross-sectional front view of a through anchor 4A according to a reference example , FIG. 5 (a) is a cross-sectional view taken along the line V-V of FIG. 4, and FIG. It is sectional drawing of the same part as Fig.5 (a) at the time of a pretensioner mechanism action | operation. 4 and 5, the same reference numerals as those in FIGS. 1 and 2 denote the same parts.
[0031]
In the through anchor 4A, the shear pin 60 is omitted from the through anchor 4 described above, and instead of the shear pin 60, the left and right convex portions 54 and 54 of the anchor base 50 are used as the cylindrical body support portion below the cylindrical body 44. And a pair of projecting pieces 62 and 62 for supporting the cylindrical body 44 are provided.
[0032]
The projecting piece 62 firmly supports the cylindrical body 44 from below so that the sawtooth portion 48 on the inner peripheral surface of the cylindrical body 44 and the sawtooth portion 46 on the outer peripheral surface of the shaft 42 are separated from each other. When a pressing force exceeding a predetermined value is applied, the sawtooth portion 46 and the sawtooth portion 48 are allowed to engage with each other.
[0033]
Also in this reference example , when the sawtooth portions 46 and 48 are engaged with each other, the rotation of the cylindrical body 44 in the direction in which the webbing applied to the cylindrical body 44 is wound around the retractor (hereinafter referred to as this direction). Rotation of the cylindrical body 44 in the direction in which the webbing is pulled out from the retractor (hereinafter, rotation in this direction is referred to as “reverse rotation”). It has a tooth shape that constitutes a one-way mechanism. Further, the diameter of the inner peripheral side of the cylindrical body 44 is larger than the outer diameter of the shaft 42. When the shaft 42 and the cylindrical body 44 are arranged coaxially, the sawtooth portion 46 and the sawtooth portion 48 are separated from each other. They are not engaged with each other.
[0034]
Further, the projecting piece 62 has a shape in which the upper surface (the surface in contact with the cylindrical body 44) is curved along the outer peripheral surface of the cylindrical body 44 as shown in FIG. 5 (a). The protruding piece 62 is in contact with the cylindrical body 44 in a non-coupled manner. For this reason, the cylindrical body 44 is normally supported by the overhanging piece 62 and slides along the upper surface of the overhanging piece 62 so that the sawtooth portion 46 and the sawtooth portion 48 do not engage with each other. The shaft 42 can freely rotate in the forward direction and the reverse direction.
[0035]
The other structure of the through anchor 4A is the same as that of the through anchor 4 described above, and is used in a seat belt apparatus such as an automobile as shown in FIG.
[0036]
In the seatbelt device provided with the through anchor 4A configured as described above, the cylindrical body 44 on which the seatbelt webbing is normally applied can freely rotate in both forward and reverse directions, so that the webbing can be wound very smoothly. Can be unwound and taken up. Of course, even in the seat belt device provided with the through anchor 4A, when the pretensioner mechanism is operated, the protruding piece 62 is broken by the pressing force from the webbing and the sawtooth portions 46 and 48 are engaged with each other. Since the cylinder 44 is rotated in the forward direction and the webbing is smoothly wound up, the cylinder is prevented from rotating in the reverse direction when the EA mechanism is operated thereafter. A large frictional force is generated, and the load applied to the EA mechanism is reduced.
[0037]
【The invention's effect】
As described above, according to the present invention, the webbing can be taken very smoothly by the pretensioner mechanism of the retractor. In addition, the load applied from the webbing to the EA mechanism of the retractor is reduced, and the weight and price of the EA mechanism can be reduced.
[Brief description of the drawings]
FIG. 1 is a front configuration diagram of a through anchor of a seat belt according to an embodiment of the present invention.
2 is a cross-sectional view showing a configuration of a hanging shaft portion of the through anchor shown in FIG. 1. FIG.
FIG. 3 is an overall view showing an example of a seat belt device according to the embodiment.
FIG. 4 is a front configuration diagram of a through anchor of a seat belt according to a reference example .
FIG. 5 is a cross-sectional view showing a configuration of a hanging shaft portion of the through anchor shown in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Webbing 2 Retractor 4, 4A Through anchor 40 Hanging shaft 42 Shaft 44 Cylindrical body 46,48 Serrated part 50 Anchor base 54 Convex part 60 Shear pin 62 Overhang piece

Claims (2)

In a through anchor of a seat belt having a hanging shaft on which a webbing pulled out from a retractor is hung, and an anchor base that supports both ends of the hanging shaft,
The hanging shaft includes a shaft whose both ends are supported by the anchor base, and a cylindrical body externally fitted to the shaft.
When a predetermined pressing force is applied to the cylinder from the webbing, the cylinder is allowed to rotate in the direction in which the webbing is pulled out by the retractor, and the cylinder is rotated in the direction in which the webbing is pulled out from the retractor. It is a through anchor of a seat belt equipped with a one-way mechanism for blocking ,
The one-way mechanism is
Sawtooth portions respectively provided on the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical body;
A support member that supports the cylindrical body with respect to the shaft so that the sawtooth portion of the cylindrical body is spaced apart from the sawtooth portion of the shaft;
The support member deforms or breaks when a predetermined pressing force is applied to the cylindrical body from the webbing, and engages the sawtooth portion of the cylindrical body and the sawtooth portion of the shaft,
The saw-tooth portion has a tooth shape that, when engaged, allows the cylinder to rotate in the direction in which the webbing is withdrawn by the retractor and prevents the cylinder from rotating in the direction in which the webbing is withdrawn from the retractor. and through anchor of the seat belt, characterized in that are. 2. The seat belt according to claim 1 , wherein the support member is formed of a shear pin, and when the pressing force exceeding the predetermined value is applied to the cylindrical body, the support member is sheared to engage the sawtooth portions. Through anchor.

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