JPH07125586A - Air bag - Google Patents

Abstract

PURPOSE:To unfold an air bag quickly and flatly. CONSTITUTION:Peripheral parts between an upper ground fabric 15 being opposed to an occupant and a lower ground fabric at the side of a steering wheel body are sealed up with each other, forming a body air bag 11. A gas inlet port 18, where an inflator spraying gas is inserted in, is formed in an almost central part of the lower ground fabric 16. IN addition, both these upper and lower ground fabrics are sewed up at plural parts 24 at several spots. Each sewing part 24 is made up into an almost V-shaped form extended with a sewing body part 26 toward the outer circumferential side from a base part 25 installed at the inner circumferential side of the air bag 11. In this sewing body part 26, a straight line part and a crank part are alternately formed. When gas is sprayed out of the inflator, the air bag 11 is developed into flat-form, then thread of the sewing part 24 is successively cut fro the base part 25 into being inflated to the side of an occupant. Therefore, such a fear that the sewing part 24 is cut off at a stretch is preventable owing to the crank part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag for protecting an occupant such as an automobile by inflating and deploying due to inflow of gas.

[0002]

2. Description of the Related Art Conventionally, an airbag device provided in a steering wheel or an instrument panel of an automobile has been used. And this airbag device
Normally, it is composed of a bag-shaped airbag folded and stored, an inflator controlled by an impact sensor to rapidly inject gas, and the like. Then, in the event of a car collision or the like, gas is rapidly injected from the inflator into the inside of the airbag, and the airbag is inflated and deployed to the front of the occupant so that the occupant can see the rim of the steering wheel, windshield, etc. A collision is prevented and this occupant is protected from the impact of the collision.

Therefore, the airbag is required to be rapidly inflated and deployed by rapidly filling the inside with gas, and is also required to be widely inflated and deployed in a flat shape in front of the occupant. .

In this respect, for example, Japanese Patent Publication No. 56-43890
As described in Japanese Patent Publication No. JP-A-2003-264, there is known a structure in which a separate insert is provided inside the airbag. The insert has a suspending cord that connects the bottom portion of the steering wheel main body near the inflator and the central portion of the airbag facing the occupant side. The protrusion size of the central portion is regulated so that the airbag is inflated and expanded.

However, this Japanese Patent Publication No. 56-4389
The configuration described in Japanese Patent No. 0 has a problem that the structure of the airbag is complicated because the separate insert is provided inside the airbag, and the manufacturing cost of the airbag device increases. Further, in this configuration, since the protrusion of the airbag during deployment is regulated by the hanging string of the insert body, the inertial force of the airbag causes the center portion of the airbag to deform so as to dent toward the steering wheel body side at the end of deployment. There is a problem with that.

Further, for example, an airbag disclosed in Japanese Utility Model Laid-Open No. 2-71051 is known. This airbag is formed in a bag shape by stitching the peripheral part of the front side base fabric facing the occupant side and the back side base fabric located on the steering wheel main body side, and is formed in the center part of the back side base fabric. Has a through hole into which the inflator is inserted.

Further, the airbag is provided with a sewn portion in which the front side base cloth and the back side base cloth are sewn to each other with a thread or the like in a substantially fan shape in plan view. The sewn portion is formed at a plurality of positions so as to surround the inflator, and between these sewn portions,
A radial communication portion is formed to connect the vicinity of the inflator and the vicinity of the outer peripheral portion inside the airbag.

Then, when the gas is injected from the inflator, the gas first fills the vicinity of the outer peripheral portion of the airbag through the communicating portion, and the airbag is deployed in a flat shape. Then, when the pressure of the gas inside the airbag rises above a predetermined value, the pressure at which the airbag expands cuts the thread at each sewn portion, causing the airbag to expand to the occupant side all at once. ing.

[0009]

However, in the structure described in Japanese Utility Model Laid-Open No. 2-71051, the gas pressure inside the airbag is set to a predetermined value after the gas is filled near the outer peripheral portion of the airbag. In the state of rising above, the thread of each sewn portion is cut, and the airbag inflates toward the occupant side at once, so it is complicated to control the timing of cutting the thread, and the manufacturing cost of the airbag increases. I have a problem.

The present invention has been made in view of the above points, and is made flat by introducing gas, and
An object of the present invention is to provide an airbag that can be smoothly deployed and can be manufactured at a reduced cost.

[0011]

The airbag of the present invention comprises:
The front side base fabric facing the occupant and the back side base fabric provided with a gas introduction port for introducing gas in the substantially central part are sealed together at their peripheral portions, and the front side base fabric and the back side base fabric are In an airbag that has a sewn portion that is sewn to a cloth so as to be separable from each other, and inflates and deploys by separating the sewn portion by the pressure of the gas inflow from the gas inlet, the sewn portion is A sewing main body is formed from the inner peripheral side to the outer peripheral side in the vicinity of the gas introduction port, and a plurality of separation limiting portions for restricting the progress of separation are formed at predetermined intervals on the sewing main body, and the inflow of the gas is performed. The pressure causes the separation from the inner peripheral side to the outer peripheral side in sequence.

[0012]

In the airbag of the present invention, the sewn portion formed by sewing the front side fabric and the back side fabric of the airbag to each other is formed from the inner peripheral side near the introduction port toward the outer peripheral side. In addition, a plurality of separation limiting portions that restrict the progress of separation are formed at predetermined intervals in the sewing main body that constitutes this sewing portion. Therefore, when gas is introduced into this airbag,
This airbag is flatly inflated and expanded by being filled with gas up to the outer peripheral side while the protrusion to the occupant side is restricted by the sewn portion, and the sewn portion is sequentially inflated from the inner peripheral side to the outer peripheral side by the pressure of the gas inflow. Separation progresses, and the passenger expands and deploys. At this time, since the progress of the separation is restricted by the separation restriction portions formed at a plurality of predetermined intervals, the airbag is inflated and deployed smoothly toward the occupant while suppressing the sudden protrusion toward the occupant.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of an embodiment of the airbag of the present invention will be described below with reference to the drawings.

1 to 3, reference numeral 11 denotes an airbag, which is folded and stored in an airbag device mounted on a boss portion located in the center of a steering wheel body of an automobile (not shown). It has become so. The airbag device is provided with a substantially columnar inflator 12 for injecting a gas such as nitrogen gas under the control of an impact sensor (not shown), and a large number of gases formed on the side surface when the automobile collides. Injection port 12a
The gas is suddenly injected into the inside of the airbag 11 from this to inflate and deploy the airbag 11 to the front of the occupant to prevent the occupant from colliding with the rim portion of the steering wheel body or the windshield. ing.

Further, the airbag 11 is formed into a flat bag shape by stitching together peripheral portions of two cloths each having a substantially circular plane shape. That is, the airbag 11 has an upper side base fabric 15 as a front side base fabric located on the occupant side and a lower side base fabric 16 as a back side base fabric located on the steering wheel body side. The peripheral portions of the upper and lower base fabrics 15 and 16 are firmly sewn together by at least one thread 17 and sealed.

A circular hole-shaped gas introduction port 18 is formed in the central portion of the lower base cloth 16, and the upper portion of the inflator 12 is inserted into the gas introduction port 18. Further, around the gas introducing port 18, two reinforcing cloths 19 and 20 having an annular shape are sewn to form a reinforcing portion 21. Then, the reinforcing portion 21 has a through hole 21a for rivets.
Etc. are formed, and this reinforcing portion 21 is used for the inflator.
It is adapted to be fixed to a base plate 12 or the like, which is attached to the steering wheel body 12 or the like, by using rivets and bolts. Also,
The reinforcing cloth 20 on the steering wheel body side has a larger diameter than the reinforcing cloth 19 on the passenger side and extends toward the outer peripheral side.

Further, the lower base cloth 16 has circular vent holes 22 formed at one or more locations,
The gas filled in the airbag 11 is discharged from the vent hole 22.

As shown in FIGS. 1 and 3 to 5, the upper base cloth 15 and the lower base cloth 16 are made of nylon upper thread a and lower cloth at the sewing portions 24 formed at a plurality of positions. Thread b
Are sewn together by. Then, these sewing parts 24 are, as shown in FIG.
It is located between 17 and the gas inlet 18, and is formed in four rotationally symmetrical shapes with the gas inlet 18 at an angle of about 90 degrees with respect to each other. It is located in the upper left, lower right, and lower left.

Further, as shown in FIGS. 1 and 5, each sewing portion 24 has two sewing main body portions 26 extending outward from a base portion 25 formed on the reinforcing portion 21 and extending outward. The airbag 11 is formed in a substantially V-shape, and is formed in a substantially line-symmetrical shape centered on the radial direction of the airbag 11. Then, the base 25 includes the airbag 11
Is formed linearly with the circumferential direction as the longitudinal direction, and the upper and lower base fabrics 15 and 16 and the reinforcing fabric 20 having a large diameter are sewn together. Further, in each sewing main body portion 26, a linear portion 27 having a linear shape and a crank portion 28 as a separation limiting portion are alternately set. The crank portion 28 is formed symmetrically on the sewing main body portions 26 on both sides, and is formed so as to project in a direction away from each other. In addition, continuously to the tip of each sewing main body 26,
The folded-back portion 29 is formed toward the direction away from each other and toward the inner peripheral side of the airbag 11.

As shown in FIG. 4, the upper thread a and the lower thread b are sewn at a constant pitch using a sewing machine or the like, and the upper thread a has a thickness of 300 denier to 840 denier. Nylon thread is used, whereas the lower thread b uses 800 to 1300 denier nylon thread, and the lower thread b is lower than the upper thread a.
Is set to have a higher tensile strength. In addition, the upper thread a is coated with silicon spray during sewing so that it slides well.

Next, the operation of this embodiment will be described.

First, the propellant charged in the inflator 12 is ignited in a state where the impact sensor detects an impact such as a collision, and the gas injection port provided on the side surface of the inflator 12 is ignited.
High-temperature and high-pressure nitrogen gas is injected from 12a.

Then, this gas fills the inside of the airbag 11 and starts to inflate and deploy the airbag 11.
In this state, since the upper and lower base fabrics 15 and 16 are sewn together by the respective sewn portions 24, the central portion of the upper base fabric 15 does not immediately project to the occupant side, and the gas is in the middle between the sewn portions 24. After passing through the section, the peripheral section is filled and the airbag 11 spreads in a flat shape on the front surface of the occupant so as to cover the steering wheel body.

When the internal pressure of the airbag 11 rises to a certain limit in the process of deploying the airbag 11, that is, when the pressure at which the upper and lower base fabrics 15 and 16 try to separate from each other exceeds a certain value, The pressure is concentrated on the base portion 25 located at the inner end of each sewing portion 24, and the base cloth 1 on the upper and lower sides from the base portion 25 is
At least one of the upper and lower threads a and b obtained by sewing 5 and 16 together is cut.

When the gas further flows in, the upper and lower threads a and b are cut along the sewing main body portion 26 of each sewing portion 24. At this time, the sewing main body portion 26 is formed from the inner peripheral portion of the airbag 11 toward the outer peripheral portion, and since the linear portions 27 and the crank portions 28 are alternately formed,
The progress of separation at the crank portion 28 is delayed, and the cutting does not proceed at a stretch. Therefore, as the cutting of the sewing main body portion 26 progresses, the airbag 11 gradually inflates and projects toward the occupant.

Approximately 0.03 seconds after the collision of the automobile, the airbag 11 is inflated and expanded into a predetermined shape to catch the occupant leaning forward and collide with the rim portion of the steering wheel body or the windshield. Prevent and then
Gas is discharged from the vent hole 22 and rapidly reduced to secure the visibility of the occupants.

As described above, according to the airbag 11 of this embodiment, the upper and lower base fabrics 15 and 16 of the airbag 11 are sewn at the sewing portions 24.
Since the airbag 11 is sewn together with the airbag 11, the airbag 11 can be deployed in a flat shape on the front surface of the occupant, and the straight portions 27 and the crank portions 28 are alternately formed on each sewing portion 24, so that the upper and lower base fabrics 15 of the airbag 11 can be formed. Each sewn portion 24 sewn up with 16 is cut sequentially from the base 25 without being cut at a stretch, and the separation progresses smoothly, so that the airbag 11 is smoothly inflated and deployed without being deployed to the occupant side at once, and the airbag is The impact force toward the occupant side of 11 can be reduced.

Further, since each sewn portion 24 is gradually separated from the base portion 25, the cutting can be started from a state where the internal pressure of the airbag 11 is not so high, and the expanding process of deploying the folded airbag 11 And, the process of projecting to the occupant side while cutting each sewing portion 24 can be simultaneously advanced. Therefore, the airbag 11 can be quickly inflated and deployed into a predetermined shape as compared with a configuration in which the step of deploying the airbag 11 and the step of cutting and inflating the sewn portion 24 are sequentially performed.

Further, since it is not necessary to incorporate a separate insert or the like inside the airbag 11, the structure of the airbag 11 can be simplified and the manufacturing cost of the airbag 11 can be reduced.

Two reinforcing cloths constituting the reinforcing portion 21.
Reinforcement cloth 20 on the steering wheel body side out of 19, 20
Has a large diametrical dimension.
Since the base portion 25 is formed, even if stress is concentrated on the base portion 25, it is possible to prevent the lower base cloth 16 from being damaged.

Further, the base portion 25 of the sewing portion 24 is an airbag.
Since it is formed in a straight line whose longitudinal direction is the circumferential direction of 11, the stress applied to the base portion 25 is dispersed a little, and damage to the lower base cloth 16 and the like are prevented, and the upper and lower threads a of the sewing main body portion 26 are , B
The disconnection can be started.

Further, in the above-mentioned embodiment, as shown in FIG. 1, the sewn portions 24 are formed at four positions with the gas introduction port 18 as the center at an angle of about 90 degrees from each other. Seen from the occupant, they are placed in the upper right, upper left, lower right, and lower left, respectively, so that the gas can be quickly filled in the downward direction, and the airbag 11 can be rapidly deployed in the occupant's abdominal direction, The abdomen of an occupant having a small distance can be protected more quickly and surely. Then, when the airbag 11 is folded and stored, the portion that expands in the occupant's abdominal direction is folded at the end so that this part can be expanded first and can be expanded more quickly in the occupant's abdominal direction. it can.

Incidentally, as shown in FIG.
Formed in three places through an angle of 20 degrees, or as shown in FIG.
It can also be formed at five locations through an angle of about 72 degrees, as shown in FIG. Even in such a case, by not forming the sewn portion 24 near the occupant's abdomen, the airbag 11 can be rapidly deployed in the occupant's abdomen direction.

Further, as shown in FIG. 8, for example, sewn portions 24 are formed at three locations, and a fragile sewn portion 24a made of a thread having a lower tensile strength than the other sewn portions is formed at one location. By arranging the fragile sewn portion 24a toward the occupant's abdomen, the airbag 11 can be rapidly deployed toward the occupant's abdomen.

In each of the above embodiments, the sewing portion 24
Is formed into a substantially V-shaped plane having a linear base portion 25. For example, as shown in FIG. 9, the base portion 25 is an acute-angled corner portion, and the threads a above and below the sewn portion 24 can be more quickly formed. It is also possible to start the cutting of b.

Further, as shown in FIG. 10, the sewing portion 24 can be formed in a stepwise shape from a base portion 25 having an acute angle, which is sequentially expanded.

As described above, the sewn portion 24 has an appropriate shape according to the specifications such as the size, shape, and material of the airbag 11.
The number of items can be used properly.

Further, in each of the above embodiments, the sewing main body portion
By forming a crank portion 28 that projects laterally from the longitudinal direction of 26, the speed at which the yarns a and b are cut is adjusted,
Although the protrusion speed of the airbag 11 is adjusted, for example, as shown in FIG.
As shown in FIGS. 13A to 13C, the separation limiting portion alternately formed with the linear portion 27 can be formed by the pitch changing portion 31 formed by partially changing the sewing pitch.

Also, by forming the pitch changing portion 31 as described above, it is possible to prevent the threads a and b from being cut at a stretch and the sewn portion 24 to be separated from each other at a stretch, and to inflate and deploy the airbag 11 smoothly. In addition, the number of sewing steps can be reduced, and the manufacturing cost of the airbag 11 can be reduced.

Further, also in the structure in which the pitch changing portion 31 is formed, as shown in FIG. 12, the base portion 25 is formed in a substantially planar V shape in a straight line shape, and as shown in FIG. It is also possible to form the base portion 25 into a substantially V-shaped plane with sharp corners.

Further, as shown in FIG. 15, for example, the crank portion 28 projecting laterally in each of the above-described embodiments and the pitch changing portion 31 by changing the sewing pitch are appropriately combined,
The sewing main body portion 26 can also be formed in an inclined step shape.

In each of the above embodiments, the sewing main body 26
The tip end portion on the outer peripheral side of the sewing machine is folded back in a direction in which it is separated from each other to form the folding back portion 29. As shown in FIG.
The folding-back portion 33 can be formed by bending the tip ends of the sewing main body portions 26 on both sides of 24 once in a direction in which they approach each other, and further by folding back the same toward the inner peripheral side of the airbag 11 in an inclined shape.

In each of the above-mentioned embodiments, when the airbag 11 is inflated and deployed, an inertial force acts, and this inertial force gradually becomes stronger as it approaches the outer peripheral portion, and therefore the force for separating the sewn portion 24 is also increased. It becomes larger as it approaches the outer periphery of the airbag 11. Therefore, as the outer peripheral portion of the airbag 11 is approached, the sewing pitch of each portion of the sewn portion 24 is narrowed, or the protrusion size of the crank portion 28 is increased to increase the force required for separation, thereby increasing the air pressure. The bag 11 can be inflated and expanded more smoothly.

Further, in the airbag 11, the last folded portion is deployed first, and the first folded portion is deployed last. However, depending on the folding shape of the airbag 11, the last folded portion is deployed. When doing an airbag
The pressure of the gas that deploys 11 may weaken. Therefore, regarding the part where the gas pressure becomes weak,
By weakening the strength of the threads a and b of the sewn portion 24 or not forming the sewn portion 24 partially, the airbag 11 can be inflated and deployed more smoothly.

Further, in each of the above-mentioned embodiments, the sewing portion 24 is formed by using the nylon upper thread a and the lower thread b. However, for example, one thread or three or more threads are used, or a thread other than nylon is used. Alternatively, the upper base cloth 15 and the lower base cloth 16 may be adhered to each other so as to be separable from each other using an adhesive or the like.

In each of the above-described embodiments, the airbag 11 of the airbag device provided in the steering wheel has been described. However, for example, the airbag for passengers in the front passenger seat and the airbag for passengers in the rear seat are also described. Can be applied.

[0047]

According to the air bag of the present invention, when gas is introduced into the air bag, the air bag is flattened by being filled with gas up to the outer peripheral side while being restricted from protruding toward the occupant by the sewing portion. As the gas is inflated and expanded, the separation of the sewn portion gradually progresses from the inner peripheral side to the outer peripheral side due to the pressure of the gas inflow, and the sewn part is inflated and expanded toward the passenger side. At this time, since the progress of the separation is restricted by the sewing main body portion formed from the inner peripheral side toward the outer peripheral side and the plurality of separation limiting portions formed in the sewing main body portion at a predetermined interval, the occupant side of the airbag The airbag can be smoothly inflated and deployed by suppressing the sudden protrusion to the airbag. In addition, the structure is simple and the manufacturing cost of the airbag can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of an airbag of the present invention.

FIG. 2 is an explanatory diagram of an airbag and an inflator of the same.

FIG. 3 is a partial cross-sectional view of the same airbag.

FIG. 4 is a cross-sectional view of the same sewing portion.

FIG. 5 is a plan view of the same sewing section.

FIG. 6 is a plan view showing another embodiment of the airbag of the present invention.

FIG. 7 is a plan view showing another embodiment of the airbag of the present invention.

FIG. 8 is a plan view showing another embodiment of the airbag of the present invention.

FIG. 9 is a plan view showing another embodiment of the sewing part of the present invention.

FIG. 10 is a plan view showing another embodiment of the sewing part of the present invention.

FIG. 11 is a plan view showing another embodiment of the airbag of the present invention.

FIG. 12 is a plan view of the same sewing section.

FIG. 13 is a sectional view of the same sewing section.

FIG. 14 is a plan view showing another embodiment of the sewing part of the present invention.

FIG. 15 is a plan view showing another embodiment of the sewing part of the present invention.

FIG. 16 is a plan view showing another embodiment of the sewing part of the present invention.

[Explanation of symbols]

 11 Airbag 15 Upper base fabric as front fabric 16 Lower base fabric as back fabric 18 Gas inlet 24 Sewing part 26 Sewing body 28 Crank part as separation restricting part 31 Pitch as separation restricting part Change part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsugu Yamada 218 Aoshima-cho, Fuji-shi, Shizuoka Japan Plast Co., Ltd.

Claims (1)

[Claims] 1. A front side base cloth facing an occupant and a back side base cloth provided with a gas introduction port for introducing gas at a substantially central portion are sealed together at their peripheral portions, and these front side base cloths are sealed together. An airbag that has a sewn portion formed by sewn a cloth and a base cloth on the back side so as to be separable from each other, and inflates and deploys by separating the sewn portion by the pressure of gas inflow from the gas inlet, At least a part of the sewing portion is formed with a sewing main body portion from the inner peripheral side in the vicinity of the gas introduction port toward the outer peripheral side, and the separation limiting portion for restricting the progress of separation is provided at a predetermined interval on the sewing main body portion. The airbag is characterized in that a plurality of them are formed, and the pressure of the inflow of the gas causes the separation to proceed in sequence from the inner peripheral side to the outer peripheral side.