JP4357721B2 - Seat belt device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seat belt device that restrains an occupant or the like of a vehicle on a seat, and more particularly to a seat belt device including a retractor with an energy absorbing mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a seat belt device for safely holding a vehicle occupant or the like in a seat, as a retractor for a seat belt that winds a webbing so that it can be pulled out, inertial sensing means that reacts to sudden acceleration, collision or deceleration The emergency lock type retractor which is equipped with the emergency lock mechanism which physically locks the webbing drawer by the above and which restrains the occupant effectively and safely is used.
[0003]
As such an emergency lock type retractor, for example, like a retractor for a seat belt disclosed in Japanese Patent Publication No. 59-21624, etc., an engagement provided at one end of a twisting rod around which a webbing is wound. In some cases, a member is provided with a lock means that engages with an engaged portion of a retractor base in a vehicle emergency to prevent the twisting rod from rotating in the webbing pull-out direction.
[0004]
And in the said locking means, the ratchet tooth formed in the latching engagement part formed in the torsion bar through-hole of the retractor base through which the torsion bar penetrates, or the internal tooth plate attached to the torsion bar through-hole On the other hand, a lock plate or a locking claw that rotates with a torsion bar is used as an engagement member while being used as an engaged part. Is configured to prevent rotation in the webbing pull-out direction.
[0005]
However, when the impact force due to the collision is large, the webbing tension increases with the lapse of time after the collision, so that a rapid deceleration occurs in the occupant's body, and the load applied to the occupant from the webbing increases. Therefore, when the load acting on the webbing exceeds a predetermined value set in advance, the webbing is advanced by a predetermined amount, thereby providing an energy absorption mechanism that absorbs the impact generated on the occupant's body. Various seat belt retractors designed to protect the body have been proposed. As a seat belt retractor having such a configuration, “especially an energy absorbing device for a safety belt” described in JP-A No. 46-7710 is known.
[0006]
In the energy absorbing device, a substantially cylindrical bobbin around which a webbing is wound, and a torsion bar that is inserted through the center of the bobbin and is integrally connected to the bobbin and rotatably supported by a retractor base. A locking base that is integrally connected to the other end of the torsion bar, and an emergency locking mechanism that prevents the bobbin from rotating in the webbing pull-out direction by engaging the locking base with the retractor base in the event of a vehicle emergency And when the load in the webbing pull-out direction acting on the bobbin when the emergency lock mechanism is activated exceeds a predetermined value, the torsional rod causes torsional deformation to allow the bobbin to rotate in the webbing pull-out direction. Absorbs impact energy.
[0007]
That is, when the load in the webbing pull-out direction acting on the bobbin exceeds a predetermined value, the torsion rod inserted through the center of the bobbin is twisted around the axis, and the bobbin rotates in the webbing pull-out direction due to the twist. The webbing can be pulled out by the amount, the occupant restraint force by the webbing is relaxed, and the impact acting on the occupant from the webbing is reduced.
[0008]
[Problems to be solved by the invention]
However, the impact at the time of collision differs depending on the vehicle structure. Therefore, in order to sufficiently protect the occupant's body, for example, a set load at which the energy absorption mechanism starts to operate (called an energy absorption load, in fact, a webbing tension at which energy absorption starts) or shock absorption It is required to change the design of the amount of deformation at the time (actually, the amount of webbing extension) according to the vehicle structure and the like.
[0009]
Further, when the webbing is pulled out by the energy absorbing mechanism, the passenger moves in the collision direction accordingly. At that time, in order to prevent the occupant's body from colliding with the vehicle interior wall, in recent vehicles, the vehicle bulges between the occupant and the vehicle interior wall in the event of a vehicle emergency, and catches the occupant's body. Equipped with an SRS airbag system that protects the occupant's body, and measures to improve the occupant's safety in cooperation with the seat belt device have become widespread.
[0010]
And when such an SRS airbag system is provided, since the effect of an SRS airbag system is drawn out safely and to the maximum, it is requested | required to give the characteristic of an energy absorption mechanism a change. For example, at the beginning of the collision until the occupant comes into contact with the inflated airbag, a large energy absorption load is secured to minimize the movement of the occupant, and the energy absorption load is applied in the latter half of the collision when the airbag begins to restrain the occupant. This is a request to leave the passengers to the airbag system.
[0011]
From the viewpoint of optimization of energy absorption load according to the above vehicle structure differences and role sharing with the SRS airbag system, the energy absorption mechanism can be changed in characteristics such as energy absorption load. Flexibility and high design freedom are required.
[0012]
An object of the present invention is to eliminate the above-mentioned problem, and the energy absorption mechanism of the seat belt retractor can have an energy absorption characteristic in which an energy absorption load changes during operation, and an occupant by improving the energy absorption characteristic It is providing the seatbelt apparatus provided with the retractor with an energy absorption mechanism which can aim at the safety improvement of this.
[0013]
[Means for Solving the Problems]
An object of the present invention is to provide a substantially cylindrical bobbin around which a webbing is wound, an emergency lock mechanism that connects a locking base to a retractor base in a vehicle emergency to prevent rotation in the webbing pull-out direction, and one end of the bobbin. A torsion bar connected to the locking base at the other end, and when the load in the webbing pull-out direction acting on the bobbin when the emergency lock mechanism is activated exceeds a predetermined value, the torsion bar causes torsional deformation. In the seat belt device provided with a retractor that absorbs impact energy by allowing rotation of the bobbin in the webbing pull-out direction,
The torsion bar has at least one intermediate connection part connected to the bobbin between the one end and the other end, and the diameter of the torsion bar is the one end side at the other end of the intermediate connection part. It is smaller than the end side, and the intermediate connecting portion is achieved by a seatbelt device characterized in that the connection with the bobbin is released in the middle of the torsional deformation of the torsion bar.
[0014]
In the present invention, it is preferable that the connection between the torsion bar and the bobbin in the intermediate connection portion is automatically released according to the rotation of the bobbin. As such a configuration, for example, when the intermediate connecting portion rotates together with the bobbin, and the member constituting the intermediate connecting portion moves in the rotation axis direction according to this rotation, and the number of rotations exceeds a certain amount, the intermediate connecting portion A configuration is possible in which the connection between the bobbin and the torsion bar is released.
[0015]
In the present invention, the retractor base and the locking base are engaged with each other by an emergency lock mechanism in the event of a vehicle emergency to prevent the locking base from rotating, thereby preventing the rotation of the torsion bar connected to the locking base at one end. In addition, this prevents the torsion bar from rotating the bobbin connected at the other end and the intermediate connecting portion. At this time, when the load in the webbing pull-out direction acting on the bobbin becomes a predetermined value or more, the torsion bar is torsionally deformed, and as a result, the bobbin is allowed to rotate.
[0016]
In the initial stage of rotation of the bobbin due to the torsional deformation of the torsion bar, the torsion bar is connected to the bobbin at one end and the intermediate connection part. In the first region), no twisting occurs, and the torsion bar is twisted and deformed between the intermediate connecting portion and the other end (hereinafter, the region between the two is referred to as the second region).
[0017]
In the later stage of the rotation of the bobbin due to torsional deformation, the connection between the torsion bar and the bobbin at the intermediate connection part is released. As a result, the torsion bar has one end (connection part with the bobbin) and the other end (locking base). Between the first region and the second region.
[0018]
Since the diameter of the torsion bar is smaller in the first region with respect to the intermediate connecting portion, the torsional rigidity is higher in the second region than in the first region. Accordingly, the torsional rigidity of the torsion bar is such that the intermediate connection portion is in the released state and the first region and the second region are in the initial stage of rotation in which only the second region is twisted and deformed when the intermediate connection portion is in the connected state. It is higher than the later stage of rotation in which the region twists and deforms, and the impact energy transmitted from the webbing can be absorbed more by the twisting rod. On the other hand, in the later stage of rotation, the first region having a small diameter can also be twisted, and this first region is easier to twist than the second region having a relatively large diameter. One region is twisted, and the energy absorption due to twist deformation is smaller than in the initial stage.
[0019]
Since this invention is comprised as mentioned above, it is possible to reduce the tension | tensile_strength of webbing in steps. For example, in the initial stage of emergency locking when the airbag is not activated, the amount of webbing is reduced, so that the webbing sufficiently restrains the occupant, and the airbag is activated and the occupant After the contact, the restraining force can be kept relatively low.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a seat belt device according to the invention will be described in detail with reference to the drawings.
[0021]
First, the configuration of the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a partially exploded perspective view of a seatbelt retractor according to an embodiment of the present invention, and FIGS. 2 and 3 are AA cross-sectional views in FIG.
[0022]
As shown in FIG. 1, the seatbelt retractor 1 includes a retractor base 10. The retractor base 10 is obtained by press-molding a metal plate so that left and right side plates 10a and 10b are raised from both sides of a back plate 10c fixed to a vehicle body and have a substantially U-shaped cross section. Through holes 13 and 14 are provided in the left and right side plates 10a and 10b. On the peripheral edge of the through-hole 13 of one side plate 10a (left side in the figure), internal teeth 13a are formed at intervals in the circumferential direction. A pretensioner 30 and a take-up spring device 35 are provided on the outer side of the side plate 10a (the side opposite to the side facing the other side plate 10b).
[0023]
The winding spring device 35 includes a lower case 35a that faces the side plate 10a of the retractor base 10 and an upper case 35b that is combined with the lower case 35a to form a storage space therebetween.
[0024]
The retractor base 10 has a substantially cylindrical bobbin 3 around which webbing is wound, and a substantially cylindrical energy absorbing member that is inserted into the bobbin 3 and is rotatably supported by the side plates 10 a and 10 b of the retractor base 10. A torsion bar 5 is attached. The torsion bar 5 serves as the rotation axis of the bobbin 3.
[0025]
One of the torsion bars 5 (the left end in the figure) is provided with a protrusion 5a that can be connected to the bobbin 3 via a sleeve 8 as a connecting member, and the other (the right end in the figure) has a lock. Protrusions 5b are provided that are connected to the corner portions 7d formed on the inner periphery of the boss portions 7c of the disk-shaped rocking base 7 that is a part of the member so as to be integrally rotatable. An intermediate protrusion 5f is provided between the protrusion 5a and the protrusion 5b. These protrusions 5a, 5b, and 5f are formed in a hexagonal cross-sectional shape.
[0026]
The tip 5d of the torsion bar 5 bridged between the side plates 10a and 10b of the retractor base 10 through which the one side plate 10a is inserted is rotated by the take-up spring device 35 in the webbing take-up direction. Always energized.
[0027]
The protrusion 5a of the torsion bar 5 is fitted into an insertion hole 8a having a hexagonal cross section formed in a sleeve 8 that is fitted in a hole (not shown) having a substantially triangular cross section formed on one end side of the bobbin 3. The bobbin 3 is connected to the bobbin 3 so as to be rotatable together. The shaft portion 8 b of the sleeve 8 is supported by the winding spring device 35.
[0028]
Please refer to FIG. The torsion bar 5 is inserted through the bobbin 3 and also through the set screw 29. The set screw 29 has a head portion 29a whose outer peripheral portion is a spline, and a male screw portion 29b that engages with a female screw portion 7b formed on the inner periphery of the boss portion 7c of the locking base 7, and the center thereof. The part is formed with an insertion hole 29c having a hexagonal cross section.
[0029]
In order to function as an intermediate connecting member, the set screw 29 is spline-engaged with the inner periphery of the bobbin 3 at the head portion 29a and rotates integrally with the bobbin 3, and the intermediate protrusion 5f of the torsion bar 5 at the insertion hole 29c. And the torsion bar 5 is also integrally rotated. Therefore, the bobbin 3 and the torsion bar 5 are connected via the set screw 29.
[0030]
The set screw 29 is also engaged with the locking base 7 by the male screw portion 29b. The male screw portion 29 b is screwed with a female screw portion 7 b formed on the inner periphery of the boss portion 7 c of the locking base 7, and this screwing advances as the set screw 29 rotates relative to the locking base 7, The set screw 29 moves in the direction of the rotation axis.
[0031]
The torsion bar 5 acts on the occupant's body when a rotational torque of a predetermined value or more acts between the connecting portions 5a and 5b and the deformed portion 5c between the connecting portions 5a and 5b is twisted to cause plastic deformation. An energy absorbing means configured to absorb impact energy.
[0032]
The emergency lock means connects the locking base 7 and the retractor base 10 in the event of a vehicle emergency (when sudden deceleration occurs due to an accident or when the webbing is pulled out suddenly). By blocking the rotation in the webbing pull-out direction, the rotation of the bobbin 3 in the webbing pull-out direction is blocked. As the specific configuration of the emergency lock means, various known ones can be adopted.
[0033]
As shown in FIG. 1, the emergency locking means of the present embodiment is rotatably supported by a pin 7a of the locking base 7, and serves as a locking member (a part of the locking member) having a locking tooth 9a at the tip. It includes a first pole 9 and a latch plate 15 provided with side teeth 10b of the retractor base 10 and formed with internal teeth 15g that can engage with the locking teeth 9a of the first pole 9. This emergency locking means connects the locking base 7 and the retractor base 10 by engaging the locking teeth 9a of the first pole 9 with the internal teeth 15g of the latch plate 15 fixed to the side plate 10b in the event of a vehicle emergency. The rotation of the locking base 7 in the webbing pull-out direction is prevented.
[0034]
Next, the operation of the seatbelt retractor 1 according to the first embodiment will be described with reference to FIGS. 2 and 3. When the emergency locking means is activated in the event of a vehicle emergency such as a collision, first, rotation of the locking base 7 connected to the other end of the torsion bar 5 in the webbing pull-out direction is prevented. When a rotational torque of a predetermined value or more acts on one end side of the torsion bar 5 via the bobbin 3 due to the load acting on the webbing, the torsional deformation of the torsion bar 5 starts, and the amount of torsional deformation of the torsion bar 5 is as follows. As the bobbin 3 rotates in the webbing pull-out direction, impact energy is absorbed.
[0035]
In the initial stage of rotation of the bobbin 3 due to torsional deformation of the torsion bar 5, the torsion bar 5 is connected to the bobbin 3 at its bobbin connecting portion 5a, and the bobbin 3 is connected to the bobbin 3 via the set screw 29 at the intermediate protrusion 5f. Since it is connected, no torsion occurs between the bobbin connecting portion 5a and the intermediate protrusion 5f (hereinafter, the area between the bobbin connecting part 5a and the intermediate protrusion 5f), and the torsion bar 5 is connected to the intermediate protrusion 5f and the locking base. Torsional deformation occurs between the portion 5b (hereinafter, the region between the portions 5b is described as the second region 5h). In the later stage of rotation of the bobbin 3 due to torsional deformation, the connection between the torsion bar 5 and the bobbin 3 at the intermediate protrusion 5f is released. As a result, the torsion bar 5 has its bobbin connection part 5a and the locking base connection part 5b. In other words, that is, in the first region 5g and the second region 5h. The connection release between the set screw 29 and the bobbin 3 will be described later.
[0036]
Since the diameter of the torsion bar 5 is smaller in the first region 5g with respect to the intermediate projection 5f, the torsional rigidity is higher in the second region 5h than in the first region 5g. Accordingly, the torsional rigidity of the torsion bar 5 is such that the intermediate protrusion 5f is in the released state and the intermediate protrusion 5f is in the released state in the initial stage of rotation in which only the second region 5h is twisted and deformed. The first region 5g and the second region 5h are higher than the later stage of rotation in which the first region 5g and the second region 5h are twisted and deformed, and the impact energy transmitted from the webbing can be absorbed more by the twisting rod 5. On the other hand, in the later stage of rotation, the first region 5g having a small diameter can be twisted, and the first region 5g is more easily twisted than the second region 5h having a relatively large diameter. The first region 5g is mainly twisted, and the energy absorbability due to twist deformation is smaller than that in the initial stage.
[0037]
As described above, in the initial state, the intermediate protrusion 5 f and the bobbin 3 are connected via the set screw 29. When the emergency lock means is activated in the event of a vehicle emergency such as a collision, the locking base 7 is prevented from rotating. At this time, the rotational torque from the bobbin 3 is transmitted to the bobbin connecting portion 5a of the torsion bar 5 and also transmitted to the set screw 29 that is spline-engaged with the bobbin 3, so that the set screw 29 rotates. Then, the torsion bar 5 is twisted by transmitting this rotational torque to the intermediate protrusion 5f.
[0038]
Since the male screw portion 29b of the set screw 29 is screwed with the female screw portion 7b of the locking base 7, when the set screw 29 rotates relative to the locking base 7, the screwing between the male screw portion 29b and the female screw portion 7b is performed. The match progresses. As a result, the set screw moves rightward in FIG. 2, and finally the engagement between the set screw 29 and the intermediate projection 5f is released, and the state shown in FIG. 3 is obtained. In the state shown in FIG. 3, the connection between the bobbin 3 and the torsion bar 5 at the intermediate protrusion 5f (that is, the intermediate connection part) is released, so that the torsion bar 5 has the first region 5g and the second region as described above. The region 5h is twisted.
[0039]
Since this invention is comprised as mentioned above, as shown to Fig.4 (a), it is possible to reduce the tension | tensile_strength of webbing in steps. In the initial stage of energy absorption, energy is absorbed by the webbing tension f2, and in the latter stage, where the torsion bar 5 is twisted to some extent and the webbing is extended, the energy is absorbed by the webbing tension f1 smaller than the webbing tension f2. I do. Thus, for example, in the initial stage of emergency locking, such as when the airbag is not in operation, the webbing sufficiently restrains the occupant by reducing the amount of webbing, and the airbag is activated to However, after contacting the airbag, the restraining force can be kept relatively low to reduce the burden on the occupant. On the other hand, in the energy absorption of the conventional retractor shown in FIG. 4B, the diameter of the torsion bar is not multistage, so that the energy can be absorbed only with a single webbing tension f3.
[0040]
Further, in the present invention, the diameter of the torsion bar 5 in the retractor is stepwise, and in the initial stage of vehicle emergency, the torsion bar is twisted and deformed in the second region 5h having high torsional rigidity. A lot of impact energy can be absorbed by the retractor.
[0041]
【The invention's effect】
As described above, in the seat belt device of the present invention, the torsion bar of the retractor has at least one intermediate connection part that is connected to the bobbin between one end and the other end, and the diameter of the torsion bar is The one end side is smaller than the other end side with an intermediate connecting portion as a boundary, and the intermediate connecting portion is configured to be disconnected from the bobbin during the twisting deformation of the torsion bar. Therefore, the energy absorption mechanism of the seat belt retractor can have an energy absorption characteristic in which the energy absorption load changes during operation, and the safety of the occupant can be improved by improving the energy absorption characteristic.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a first embodiment of a seat belt retractor with an energy absorbing mechanism used in a seat belt device according to the present invention.
2 is a cross-sectional view of the seat belt retractor shown in FIG. 1 taken along the line AA. FIG.
FIG. 3 is a cross-sectional view of the seat belt retractor shown in FIG. 1 taken along line AA.
4A is an energy absorption characteristic of the seat belt apparatus of the present invention, and FIG. 4B is an energy absorption characteristic of the seat belt apparatus of the present invention.
[Explanation of symbols]
1 Seatbelt retractor with energy absorption mechanism 3 Bobbin 5 Torsion bar
7 Locking base 10 Retractor base 29 Set screw

Claims (1)

A substantially cylindrical bobbin around which the webbing is wound, an emergency lock mechanism that connects the locking base to the retractor base in the event of a vehicle emergency and prevents rotation in the webbing pull-out direction, one end connected to the bobbin and the other end A torsion bar coupled to a locking base, and when the load in the webbing pull-out direction acting on the bobbin when the emergency locking mechanism is activated exceeds a predetermined value, the torsional deformation of the torsion bar causes the bobbin webbing In the seat belt device provided with a retractor that absorbs impact energy while allowing rotation in the pull-out direction,
The torsion bar has at least one intermediate coupling portion coupled to the bobbin between the one end and the other end;
The diameter of the torsion bar is smaller than the other end side at the one end side with respect to the intermediate connecting portion,
The seat belt device according to claim 1, wherein the intermediate connecting portion is configured to be disconnected from the bobbin in the middle of the torsional deformation of the torsion bar.

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