JP2003019940A - Occupant protective airbag device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an occupant protective airbag device in which an airbag has first and second inflation chambers continuously provided in the longitudinal direction, and development and inflation of the first and second inflation chambers caused by introducing a gas are simultaneously performed when the gas generated in an inflator is introduced in both inflation chambers. SOLUTION: The airbag 26 comprises the first and second inflation chambers 34 and 35 which are continuously provided in the longitudinal direction and inflated by introducing the gas 24 generated in the inflator 25, a first introduction passage 36 which communicates an ejection port of the gas 24 of the inflator 25 with the first introduction passage 36, and introduces the gas 24 to the first inflation chamber 34, and a second introduction passage 37 which is disposed on the imaginary extension line of a downstream end part of the first introduction passage 36, communicates the first inflation chamber 34 with the second inflation chamber 35, and introduces a part of the gas 24 flowing out of the first introduction passage 36 into the second inflation chamber 35. A regulating means 44 for regulating the inflow of the gas 24 flowing out of a downstream end opening 39 of the first introduction passage 36 into an upstream end opening 40 of the second inflation chamber 37 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag provided with first and second inflation chambers arranged side by side in a front and rear direction so that gas generated in an inflator due to a collision of an automobile is introduced into the both inflation chambers. The present invention relates to an airbag device for protecting an occupant of an automobile.

[0002]

2. Description of the Related Art Conventionally, there is an air bag device disclosed in JP-A-11-235965.

According to the above publication, an airbag device is attached to a vehicle body to generate gas, and an inflator is attached to the vehicle body and extends along an upper edge of a side wall of the vehicle body. And an airbag that is inflatable by introducing gas and expanding along the surface of the side wall on the vehicle compartment side.

Further, the airbag has first and second inflation chambers which are arranged in front and rear and are inflatable by the introduction of the gas, and a gas outlet of the inflator communicates with the first introduction passage. First to introduce the gas into the first expansion chamber
A part of the gas flowing out from the first introduction passage is placed on the imaginary extension line of the introduction passage and the downstream end of the first introduction passage to communicate the first expansion chamber with the second expansion chamber. Second
And a second introduction passage introduced into the expansion chamber.

The first and second inflation chambers of the airbag are arranged so as to correspond to the heads of the occupants seated in the front and rear seats provided in the passenger compartment, respectively. Further, the airbag has a flat shape as a whole when deployed while the inflation chamber and the introduction path are contracted. However, normally, the airbag is zigzag when viewed in a line of sight along the longitudinal direction of the vehicle body. It is compactly folded and is housed in the passenger compartment along the upper edge of the side wall of the vehicle body.

When an impact force is applied to the automobile due to the collision of the automobile, the inflator instantaneously generates a large amount of gas on the basis of the detection signal of the sensor that detects the impact force. Eject toward the introduction path.

Then, the gas causes the pressure to expand the first introduction passage, and is introduced into the first expansion chamber through the first introduction passage. Further, a part of the gas flowing out from the downstream end portion of the first introduction passage expands the second introduction passage by the pressure, and is introduced into the second expansion chamber through the second introduction passage. As a result, the first and second expansion chambers are expanded. Then, the compactly folded air bag is deployed and inflated along the side surface of the vehicle body on the vehicle interior side.

Therefore, even if the occupants seated in the front and rear seats try to collide against the side wall of the vehicle body secondarily due to the impact force, the occupants are forced to first collide with the first and second airbags prior to this.
By contacting the portions corresponding to the second expansion chambers respectively, the above-mentioned secondary collision is prevented, so that the impact force that is applied to each occupant from the side wall of the vehicle body is mitigated, and each occupant is impacted from this impact force. Is protected.

[0009]

By the way, in the above-mentioned conventional technique, the second introduction passage is arranged on the virtual extension line of the downstream end portion of the first introduction passage. Therefore, the gas generated by the inflator is generated. However, most of this gas tends to be directed to the upstream end opening of the second introduction path due to its inertial force when flowing out of the downstream end opening through the first introduction path.

Therefore, the introduction of a predetermined amount of gas into the second expansion chamber through the second introduction passage tends to be faster than the introduction of a predetermined amount of gas into the first expansion chamber, which is The expansion and expansion of the first and second expansion chambers may cause a time lag, which is not preferable.

The present invention has been made paying attention to the above circumstances, and is provided with first and second inflating chambers in which airbags are arranged side by side in front and back, and gas generated in the inflator is introduced into both of the inflating chambers. It is an object of the present invention to allow the first and second expansion chambers to be expanded and expanded at the same time when the gas is introduced into the first and second expansion chambers.

[0012]

An airbag device for protecting an occupant of an automobile according to the present invention for solving the above problems is as follows.

As shown in FIGS. 1 to 3, the invention of claim 1 is an inflator 25 attached to the vehicle body 2 for generating gas 24, and a side wall 6 of the vehicle body 2 attached to the vehicle body 2. Extending along the upper edge of the gas 2
4 is installed to expand and inflate along the surface of the side wall 6 on the side of the passenger compartment 9, and the airbag 26 is arranged side by side in front and back to introduce the gas 24. Inflatable first and second expansion chambers 34, 35 and an outlet of the gas 24 of the inflator 25 are communicated with the first introduction passage 36 to introduce the gas 24 into the first expansion chamber 34. The first introduction chamber 36 and the first expansion chamber 34 are arranged on a virtual extension line of the downstream end of the first introduction chamber 36.
And a second introduction passage 37 for communicating a part of the gas 24 flowing out from the first introduction passage 36 into the second expansion chamber 35 and communicating the second expansion chamber 35 with the second introduction passage 37. In the bag device (hereinafter referred to as "precondition" in this section),

A restricting means 44 is provided for restricting the gas 24 flowing out of the downstream end opening 39 of the first introducing passage 36 from flowing into the upstream end opening 40 of the second introducing passage 37.

In the invention of claim 2, as shown in FIGS. 4 and 5, in the above "precondition",

When the gas 24 flowing into the second introduction passage 37 from the downstream end opening 39 of the first introduction passage 36 tries to expand the second introduction passage 37 by its pressure, the suppression of the expansion is suppressed. The means 46 is provided.

In the invention of claim 3, as illustrated in FIGS. 6 and 7, in the above “precondition”,

The gas 24, which is arranged in the vicinity of the downstream end opening 39 of the first introduction path 36 and extends along the axis of the downstream end opening 39 and flows out from the downstream end opening 39, is diverted. The split fluid 50 is provided so as to be directed to the expansion chamber 34 and the upstream end opening 40 of the second introduction passage 37.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment)

1 to 3 show the first embodiment.

In FIG. 2, reference numeral 1 is an automobile and arrow F
r indicates the front of the automobile 1.

The vehicle body 2 of the automobile 1 is supported on the traveling road surface 4 by front and rear wheels 3. The vehicle body 2 is
Side walls 6 that respectively configure the respective side parts and extend in a substantially vertical direction, a roof panel 7 that is installed on the upper edge portions of the both side walls 6, and a floor panel that is provided between the lower edge portions of the both side walls 6. 8 and the interior space of the vehicle body 2 surrounded by the side wall 6, the roof panel 7, and the floor panel 8 serves as a vehicle compartment 9.

The side wall 6 extends upward from the lower portion of the vehicle body 2 and has front ends, a center pillar 12, and a rear pillar 13, which support the roof panel 7 at the extended ends thereof, in the longitudinal direction of the vehicle body 2. Each of these pillars 11, 1
The door opening 14 formed between 2 and 13 is formed by a side door 15 that can be opened and closed.

Front and rear seats 18 and 19 are provided in the passenger compartment 9 in the vicinity of the lateral sides of the side walls 6, respectively.
The floor panels 8 and 19 are supported by the floor panel 8. An occupant 20 can be seated on each of the seats 18 and 19 in a posture of facing forward.

At the time of collision of the automobile 1, the occupant 2 seated on each of the seats 18 and 19 by the impact force applied to the automobile 1.
An airbag device 23 is provided to protect the head of the occupant 20 by preventing the secondary collision when the head of the vehicle 0 collides with the side wall 6 in the secondary collision.

The air bag device 23 is disposed on the front side of the vehicle compartment 9 and supported by the side wall 6 of the vehicle body 2, and instantaneously generates a large amount of gas 24 due to an explosion and can be ejected from the ejection port thereof. Is housed in a corner formed by the inflator 25, the upper edge of the side wall 6 and the side edge of the roof panel 7, and extends in the longitudinal direction of the vehicle body 2 along the upper edge of the side wall 6. The airbag 26 includes an extending airbag 26 and a plurality of fasteners 27 that secure the airbag 26 to the vehicle body 2.

When the airbag 26 is deployed, the airbag 26 has a flat shape as a whole, but normally, the airbag 26 is compact in a zigzag shape in the vertical direction when viewed from the line of sight along the longitudinal direction of the vehicle body 2. It is folded. The upper edge of the airbag 26 is fixed to the upper edge of the side wall 6 and / or the side edge of the roof panel 7 by the fasteners 27.

The air bag 26 introduces the gas 24 generated and ejected by the inflator 25 and extends downward from the upper end edge side of the side wall 6 along the surface of the side wall 6 on the passenger compartment 9 side. Are deployed and inflatable (Fig. 2
Medium dashed line).

The solid lines in FIGS. 1 and 3 show a state where the airbag 26 is inflated only without being inflated. The airbag 26 that has only been expanded is a flexible and slightly breathable front and back sheets 31 and 32 that face each other so as to make surface contact with each other in the width direction of the vehicle body 2, and these sheets 31 and 32. , A first expansion chamber 34, 35, and a first expansion chamber 34 formed between the sheets 31 and 32 by the connection means 33. , And second introduction paths 36 and 37. In the width direction of the vehicle body 2, the front seat 31 is located inside the passenger compartment 9, and the back seat 32 is located on the side wall 6 side. 38 is a tension line.

The first inflation chamber 34 is provided in the airbag 26.
Is formed in the middle of the vehicle body 2 in the longitudinal direction, and the second inflation chamber 35 is formed in the rear portion of the airbag 26. The first and second expansion chambers 34 and 35 are arranged in the front and rear so as to correspond to the heads of the occupants 20 seated in the front and rear seats 18 and 19, respectively, and are inflatable by introducing the gas 24. ing.

The first introduction path 36 is connected to the airbag 26.
Is formed on the front upper end of the inflator 25, and the ejection port of the gas 24 of the inflator 25 is connected to the front end of the first introduction path 36. The first introduction passage 36 allows the gas outlet of the inflator 25 to communicate with the rear upper end of the first expansion chamber 34, and introduces the gas 24 generated in the inflator 25 into the first expansion chamber 34. .

The second introduction passage 37 is connected to the first expansion chamber 34.
Located between the second inflation chamber 35 and the air bag 26.
Is molded at the upper end of. The second introduction path 37 is arranged on a virtual extension line of the downstream end (rear end) of the first introduction path 36. The second introduction passage 37 connects the rear upper end of the first expansion chamber 34 to the front upper end of the second expansion chamber 35, and a part of the gas 24 flowing out from the downstream end of the first introduction passage 36. Is introduced into the second expansion chamber 35. In this case, the downstream end opening 39 of the first introduction path 36 is the second end
It is arranged near the rear of the upstream end opening 40 of the introduction path 37.

When an impact force is applied to the automobile 1 due to the collision of the automobile 1, the inflator 25 instantaneously generates a large amount of gas 24 based on a detection signal of a sensor (not shown) that detects the impact force. Is generated and jetted toward the first introduction path 36.

Then, the gas 24 expands the first introducing passage 36 by its pressure (two-dot chain line in FIG. 3), and
It is introduced into the first expansion chamber 34 through the introduction path 36. Further, a part of the gas 24 flowing out from the downstream end portion of the first introduction passage 36 expands the second introduction passage 37 by the pressure, and the second expansion chamber 35 passes through the second introduction passage 37.
Can also be introduced. As a result, the first and second expansion chambers 34 and 35 are expanded. Then, the airbag 26 that has been compactly folded is attached to the side wall 6 of the vehicle body 2.
Is expanded and inflated along the surface of the vehicle compartment 9 side.

Therefore, even if the occupants 20 seated in the front and rear seats 18 and 19 try to collide against the side wall 6 of the vehicle body 2 by the impact force, the occupants 20 are inevitably hit by the air bags. The secondary collision is prevented by contacting the portions of 26 corresponding to the first and second expansion chambers 34, 35, respectively, so that the side wall 6 of the vehicle body 2 and the occupants 2 can be prevented.
The impact force to be applied to 0 is relaxed, and each occupant 20 is protected from this impact force.

In the above structure, a regulating means 44 is provided for regulating the gas 24 flowing out from the downstream end opening 39 of the first introducing passage 36 into the upstream end opening 40 of the second introducing passage 37. There is.

The restricting means 44 includes the second introducing passage 37.
The front and back sheets 3 forming the upstream end opening 40 of
It is formed by joining a part of the small area among the parts 1 and 32 to each other by the joining means 33.

Here, as described above, the first introduction path 36
The second introduction passage 37 is arranged on a virtual extension line of the downstream end of the inflator 25. Therefore, the gas 24 generated in the inflator 25 flows out from the downstream end opening 39 through the first introduction passage 36. When the gas 24 is made to flow, most of the gas 24 is caused by its inertial force and the upstream end opening 4 of the second introduction path 37 is
It tends to be turned to 0 (hereinafter, this is referred to as "problem in precondition" in this section).

However, since the regulating means 44 is provided as described above, the downstream end opening 39 of the first introduction path 36 is provided.
The gas 24 flown out from the second introduction path 3
It is prevented by the restriction means 44 that the gas is unilaterally introduced into the second expansion chamber 35 through the passage 7.

Therefore, the gas 24 flown out from the downstream end opening 39 of the first introduction passage 36 can be introduced into the first and second expansion chambers 34 and 35 substantially evenly. 1, second expansion chamber 34, 35
The expansion and the expansion of the occupants can be caused to occur at the same time more than each other, so that the protection of the occupants 20 corresponding to the first and second expansion chambers 34 and 35 can be equally performed (hereinafter,
In this section, this is called "effect").

The following figures show the second and third embodiments. Each of these embodiments has many points in common with the first embodiment in terms of configuration and operational effects. Therefore, common reference numerals will be given to the drawings, common description will be omitted, and different points will be mainly described. Further, the configurations of the respective parts in the respective embodiments may be combined in various ways in view of the problems and effects of the present invention.

(Second Embodiment)

4 and 5 show a second embodiment.

According to this, the gas 24 flowing into the second introduction passage 37 from the downstream end opening 39 of the first introduction passage 36.
Is provided with a suppressing means 46 for suppressing the expansion when the second introduction path 37 is expanded by the pressure.

The suppressing means 46 has the second introducing path 37.
The first folded-back portion 47 formed by folding back a part of each of the front and back sheets 31 and 32 for molding
And a second folding portion 48. The first folded-back portion 47 once temporarily removes a part of each of the front and back sheets 31 and 32 in the longitudinal direction of the second introduction path 37.
It is formed by being folded back toward the inside of the second introduction path 37 and toward the upstream side of the gas 24. The second folded portion 48 is formed by folding the folded end of each of the first folded portions 47 toward the inside of the second introduction passage 37 and toward the downstream side of the gas 24. ing.

When the gas 24 is caused to flow from the downstream end opening 39 of the first introduction path 36 to the upstream end opening 40 of the second introduction path 37, first, the gas 24 is discharged.
Starts to expand the second introduction path 37 by the pressure,
At this time, a part of the gas 24 once enters the inside of the first turn-back portion 47 and stagnates, whereby expansion of the second introduction path 37 is suppressed (dotted line in FIG. 5).

Thereafter, the pressure of the gas 24 causes the second introduction passage 37 to expand further (two-dot chain line in FIG. 5), and the gas 24 passes through the second introduction passage 37 to form the second introduction passage 37. It is introduced into the expansion chamber 35.

Here, the above-mentioned "problems in the preconditions"
However, since the suppression means 46 is provided to suppress the expansion of the second introduction path 37 as described above, the amount of the gas 24 flowing through the second introduction path 37 per unit time is suppressed. The gas 24 is prevented from being unilaterally introduced into the second expansion chamber 35 through the second introduction passage 37.

Therefore, the above "effect" occurs.

Although the above is based on the illustrated example, the suppressing means 46 may be provided only on at least one of the front and back sheets 31 and 32.

Further, the suppressing means 46 cuts a part of the front and back sheets 31 and 32 forming the upstream end opening 40 of the second introduction passage 37 by the pressure of the gas 24 at a predetermined height. You may shape | mold by making it join with the joining means 33 which used.

(Third Embodiment)

6 and 7 show a third embodiment.

According to this, the gas 24, which is arranged in the vicinity of the downstream end opening 39 of the first introduction path 36 and extends along the axis of the downstream end opening 39 and flows out from the downstream end opening 39, is diverted. A divided fluid 50 is provided to direct the first expansion chamber 34 and the upstream end opening 40 of the second introduction passage 37.

The divided fluid 50 is formed in the vicinity of the downstream end opening 39 of the first introduction passage 36, and the front and back sheets 3 are formed.
It is formed by joining a part of 1, 32 to each other by a joining means 33.

Here, the above-mentioned "problem in the precondition"
However, by providing the splitting fluid 50 as described above,
Gas 24 flowing out from the downstream end opening 39 of the first introduction path 36
Is diverted toward the first expansion chamber 34 and the upstream end opening 40 of the second introduction passage 37, so that the gas 24 is unilaterally introduced into the second expansion chamber 35 through the second introduction passage 37. It is prevented from being done.

Therefore, the above "effect" occurs.

[0059]

The effects of the present invention are as follows.

According to the first aspect of the present invention, an inflator attached to a vehicle body to generate gas, and an inflator attached to the vehicle body and extending along an upper edge of a side wall of the vehicle body are introduced to introduce the gas. An airbag that is inflatable and inflatable along a surface of the side wall on the vehicle compartment side, and the airbags are arranged in front and rear and are inflatable by introducing the gas. The chamber and the gas ejection port of the inflator are communicated with the first introduction passage to allow the gas to flow into the first gas passage.
A first introduction path to be introduced into the expansion chamber and a virtual extension line of a downstream end portion of the first introduction path are arranged to communicate the first expansion chamber with the second expansion chamber and flow out from the first introduction path. In an airbag device for protecting an occupant of a vehicle, which is provided with a second introduction path for introducing a part of the gas into the second expansion chamber (hereinafter referred to as "precondition" in this section),

A restricting means is provided for restricting the gas flowing out from the downstream end opening of the first introduction passage into the upstream end opening of the second introduction passage.

Here, as in the above "preconditions", the first
The second introduction passage is arranged on the virtual extension line of the downstream end of the introduction passage, and therefore, when the gas generated in the inflator passes through the first introduction passage and is discharged from the downstream end opening. However, most of this gas tends to be directed to the upstream end opening of the second introduction path due to its inertial force (hereinafter, in this section, this is referred to as a "problem in the precondition").

However, by providing the restricting means as described above, the gas discharged from the downstream end opening of the first introduction passage passes through the second introduction passage and is unidirectionally the second expansion chamber. It is prevented by the above-mentioned restricting means.

Therefore, the gas flowing out from the downstream end opening of the first introduction passage can be introduced into the first and second expansion chambers substantially evenly, so that the first and second expansion chambers can be introduced. The expansion and the inflation of the occupants can be caused to occur more simultaneously with each other, so that the protection of each occupant corresponding to the first and second inflation chambers is made equal to each other (hereinafter, this will be referred to as "effect". ")).

According to the second aspect of the invention, in the "precondition", the gas flowing from the downstream end opening of the first introduction passage into the second introduction passage expands the second introduction passage with its pressure. In this case, a suppressing means for suppressing this expansion is provided.

Here, the above-mentioned "problem in the precondition"
However, by suppressing the expansion of the second introducing passage by providing the suppressing means as described above, the amount of gas per unit time flowing through the second introducing passage is suppressed,
The gas is prevented from being unilaterally introduced into the second expansion chamber through the second introduction passage.

Therefore, the above "effect" occurs.

According to a third aspect of the present invention, in the above-mentioned "preconditions", it is arranged in the vicinity of the downstream end opening of the first introduction passage,
A split fluid is provided that extends along the axis of the downstream end opening and diverts the gas flowing out from the downstream end opening to direct the gas toward the first expansion chamber and the upstream end opening of the second introduction passage. .

Here, the above-mentioned "problems in the preconditions"
Although it is possible to use
Since the gas flowing out from the downstream end opening of the introduction path is divided into the first expansion chamber and the upstream end opening of the second introduction path, the gas passes through the second introduction path and is unidirectionally the second gas.
It is prevented from being introduced into the expansion chamber.

Therefore, the above "effect" occurs.

[Brief description of drawings]

FIG. 1 is a side view of an airbag device according to a first embodiment in which an airbag is only deployed.

FIG. 2 is an overall side view of an automobile according to the first embodiment.

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1 in the first embodiment.

FIG. 4 is a diagram corresponding to FIG. 1 in the second embodiment.

5 is a sectional view taken along line 5-5 of FIG. 4 in the second embodiment.

FIG. 6 is a diagram corresponding to FIG. 1 in the third embodiment.

7 is a sectional view taken along line 7-7 of FIG. 6 in the third embodiment.

[Explanation of symbols]

1 car 2 car body 6 side walls 9 car compartment 18 seats 19 seats 20 crew 23 Airbag device 24 gas 25 inflator 26 airbags 27 Fasteners 31 table sheet 32 Back sheet 33 coupling means 34 First expansion chamber 35 Second expansion chamber 36 1st introduction route 37 Second introduction route 39 Downstream end opening 40 upstream end opening 44 Control means 46 Control means 50 minutes fluid

Claims (3)

[Claims] 1. An inflator mounted on a vehicle body to generate gas, and an inflator mounted on the vehicle body and extending along an upper edge of a side wall of the vehicle body to introduce the gas to the vehicle compartment side of the side wall. And an inflatable airbag that is inflatable along the surface of the first and second inflatable airbags and is inflatable by introducing the gas.
The expansion chamber and the gas outlet of the inflator are connected to the first
A first introduction passage that communicates with the introduction passage and introduces the gas into the first expansion chamber, and the first expansion chamber is disposed on a virtual extension line of a downstream end portion of the first introduction chamber, and the first expansion chamber is connected to the second expansion chamber. An air bag device for protecting an occupant of a vehicle, which is connected to a second introduction path for communicating a part of the gas flowing out from the first introduction path into the second expansion chamber, the downstream side of the first introduction path. The gas flowing out from the end opening is
An airbag device for protecting an occupant of a vehicle, which is provided with a regulating means for regulating the inflow into the upstream end opening of the second introduction path. 2. An inflator attached to a vehicle body to generate gas, and an inflator attached to the vehicle body and extending along an upper edge of a side wall of the vehicle body to introduce the gas to the vehicle compartment side of the side wall. And an inflatable airbag that is inflatable along the surface of the first and second inflatable airbags and is inflatable by introducing the gas.
An expansion chamber and a first introduction path for communicating the gas outlet of the inflator with the first introduction path to introduce the gas into the first expansion chamber, and on a virtual extension line of the downstream end of the first introduction path. An occupant of a vehicle, which is provided with a second introduction path for communicating the first expansion chamber with the second expansion chamber and for introducing a part of the gas flowing out from the first introduction path into the second expansion chamber. In the protective airbag device, when the gas flowing from the downstream end opening of the first introduction passage into the second introduction passage tries to expand the second introduction passage by the pressure, a suppressing means for suppressing the expansion. An airbag device for protecting occupants of automobiles. 3. An inflator attached to a vehicle body to generate gas, and an inflator attached to the vehicle body and extending along an upper edge of a side wall of the vehicle body to introduce the gas into the vehicle compartment side of the side wall. And an inflatable airbag that is inflatable along the surface of the first and second inflatable airbags and is inflatable by introducing the gas.
The expansion chamber and the gas outlet of the inflator are connected to the first
A first introduction passage that communicates with the introduction passage and introduces the gas into the first expansion chamber, and the first expansion chamber is disposed on a virtual extension line of a downstream end portion of the first introduction chamber, and the first expansion chamber is connected to the second expansion chamber. An air bag device for protecting an occupant of a vehicle, which is connected to a second introduction path for communicating a part of the gas flowing out from the first introduction path into the second expansion chamber, the downstream side of the first introduction path. The gas is arranged in the vicinity of the end opening, extends along the axis of the downstream end opening, and diverts the gas flowing out from the downstream end opening toward the first expansion chamber and the upstream end opening of the second introduction passage. An airbag device for protecting passengers of automobiles that is equipped with a split fluid.