AIR BAG WITH PRESSURIZATION SPACE

Abstract

An air bag includes two inner sheets facing each other, two outer sheets located at an outer side of the two inner sheets, heat resistance material located at an inner side of any one inner sheet, a first thermal bonding line thermally bonding the two outer sheets to form air input channel, a second thermal bonding line thermally bonding the inner and outer sheets along the material with gap from the first thermal bonding line, and third thermal bonding lines extending from the second thermal bonding line oppositely to the air input channel to form air pillars, a second thermal bonding portion being formed to cross the third thermal bonding lines to thermally bond the two inner and outer sheets to form a pressurization space between the second thermal bonding portion and line, and the second thermal bonding portion being spaced apart from adjacent second thermal bonding portion to form a second passage.

Description

TECHNICAL FIELD

This disclosure relates to an air bag, and more particularly to an air bag with an excellent sealing property by forming a pressurization space in an air pillar, where a valve is positioned, to press an inner sheet, thereby pressing the valve doubly.

BACKGROUND ART

During delivery of household necessaries or other important articles, the contents are wrapped by an air bag so as to prevent the contents from being broken by external impacts.

In the appended drawings, FIG. 1 is a perspective view showing a general air bag, and FIG. 2 is a vertical sectional view taken along the line A-A′ of FIG. 1, which shows a valve of the air bag shown in FIG. 1.

As shown in FIG. 1, the air bag 10 has a valve 20 that is closed by an inner pressure of air injected into the air bag.

The air bag 10 has a rectangular structure, and an air input channel 11 is formed along one side of the air bag 10. Also, a plurality of air pillars 13 are perpendicularly formed with respect to the air input channel 11. A plurality of valves 20 respectively connect the air input channel 11 to the air pillars 13, so air supplied through the air input channel 11 is introduced to each air pillar 13 through the valves 20. If the air pillars 13 are filled with air, inner pressure is generated to press the valves 20, thereby sealing the air pillars 13 such that the air in the air pillars 13 does not go out through the valves 20.

Referring to FIGS. 1 and 2, the air bag mentioned above is explained in more detail. The air bag 10 includes two outer sheets 15 that form an overall configuration of the air bag. Also, the valve 20 includes two inner sheets 21 positioned inside the two outer sheets 15 and discontinuous heat resistance inks 23 applied to any one of facing surfaces of the two inner sheets 21, and the valve is formed by a plurality of thermal bonding lines 31, 32, 33, and thermal bonding points 41, 42. In FIG. 1, the heat resistance inks 23 applied to an inner side of the inner sheets 21 is depicted as a dotted line.

In a state that the two inner sheets 21 are positioned in the two outer sheets 15, the air input channel 11 is formed by a first thermal bonding line 31 and a second thermal bonding line 32, positioned in parallel with each other. At this time, the second thermal bonding line 32 is formed while passing the heat resistance inks 23 discontinuously formed along the inner sheets 21. Also, the first thermal bonding line 31 bonds just the two outer sheets 15.

The air input channel 11 is formed along the first thermal bonding line 31 and the second thermal bonding line 32 as mentioned above, and one side of the air input channel 11 is closed and the other side is opened. Air is injected through the other side that is open.

The outer sheet 15 and the inner sheet 21 are bonded by the second thermal bonding line 32, but regions where the heat resistance inks 23 are formed are not bonded. Thus, the air injected through the air input channel 11 is introduced to the air pillars 13 through passages 25 between the inner sheets 21, which are not thermally bonded because of the heat resistance inks 23.

In addition, the air pillars 13 are formed by third thermal bonding lines 33 extending perpendicularly from the second thermal bonding line 32, but the third thermal bonding lines 23 are alternately formed with the passages formed by the heat resistance inks 23. The air introduced to the air pillar 13 through the passage 25 fills the air pillar 13 formed by the third thermal bonding line 33.

Meanwhile, in a region of the two inner sheets 21 positioned toward the air input channel 11 with respect to the second thermal bonding line 32, one inner sheet 21 and one outer sheet 15 are bonded and fixed to each other by means of the first thermal bonding point 41. As the two outer sheets 15 are expanded due to the injected air, the inner sheets 21 respectively bonded and fixed by the first thermal bonding point 41 become wider in opposite directions to open the passage 25.

However, the two inner sheets 21 positioned toward the air pillar 13 with respect to the second thermal bonding line 32 are bonded and fixed to any one outer sheet by the second thermal bonding point 42 to close the valve 20 by the air filled in the air pillar 13.

Thus, the passages 25 are closed due to the inner pressure of the air pillars 13.

In such a general air bag, when air is injected to the air input channel 11, the air is introduced to the air pillar 13 through the passage 25. After the air filled in the air pillar 13 is introduced between the inner sheet 21 and the outer sheet 15, the air presses the two inner sheets 21 to close the passage 25.

In such a sealing method, a greater pressure is applied to a curved region of the outer sheet 15, which is thermally bonded, such as a region below the second thermal bonding line 32, than a flat region of the expanded outer sheet. It is because the curved region has a larger surface area than the flat portion, so pressure is more greatly applied to the curved region. Thus, sealing is more excellent as there are more curved regions. However, the general air bag has only one curved region to which pressure is greatly applied, namely the region below the second thermal bonding line, so it does not have a good sealing property.

DISCLOSURE

Technical Problem

The disclosure is designed to solve the above problems, and therefore the disclosure is directed to providing an air bag having an improved sealing property by forming a pressurization space such that air is not leaked, thereby sealing the air doubly.

Technical Solution

In one aspect, there is provided an air bag, which includes two inner sheets positioned to face each other, two outer sheets respectively located at an outer side of the two inner sheets, a heat resistance material located at an inner side of the two inner sheets and applied to any one of the inner sheets, a first thermal bonding line for thermally bonding the two outer sheets to form an air input channel, a second thermal bonding line for thermally bonding the inner sheets and the outer sheets along the heat resistance material with a gap from the first thermal bonding line, and third thermal bonding lines extending from the second thermal bonding line in a direction opposite to the air input channel to form air pillars, wherein a second thermal bonding portion is formed at the third thermal bonding lines in a crossing direction thereof to thermally bond the two inner sheets and the two outer sheets such that a pressurization space is formed between the second thermal bonding portion and the second thermal bonding line, and the second thermal bonding portion is spaced apart from a second thermal bonding portion extending from another adjacent third thermal bonding line to form a second passage.

Also, in one embodiment, fourth thermal bonding lines with a length smaller than an interval between the third thermal bonding lines may extend from the third thermal bonding lines in a lateral direction, and the fourth thermal bonding lines may thermally bond the two inner sheets to any one of the outer sheets, and the fourth thermal bonding lines may be formed at an opposite side to the second thermal bonding line with respect to the second thermal bonding portion.

Also, in one embodiment, the heat resistance material may be continuously applied to the inner sheets in a length direction, and the second thermal bonding line may thermally bond the inner sheets and the outer sheets along the heat resistance material.

Also, in one embodiment, a plurality of first thermal bonding portions may be formed in the air input channel in correspondence to the third thermal bonding lines, respectively, such that adjacent first thermal bonding portions are spaced apart from each other to form a first passage, and a part of the first thermal bonding portions may thermally bond the two outer sheets and the other part of the first thermal bonding portions may thermally bond the outer sheets to the inner sheets.

Also, in one embodiment, at least one thermal bonding point for thermally bonding the two outer sheets in a direction perpendicular to the air pillars may be formed at a middle of each air pillar in a length direction thereof.

Also, in one embodiment, both ends of the air input channel may be closed, and a cock may be formed at any one of the outer sheets corresponding to the air input channel.

ADVANTAGEOUS EFFECTS

As described above, the air bag disclosed herein exhibits an excellent durability since the air filled in an air pillar is sealed doubly to minimize air leakage.

In addition, the air bag disclosed herein is less restricted in locations of thermal bonding lines and points since a heat resistance ink is applied over the entire length of a valve, which ensures easier work, thereby improving productivity and lowering an inferiority rate.

DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of the disclosed exemplary embodiments will be more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view showing a general air bag;

FIG. 2 is a vertical sectional view taken along the line A-A′ of FIG. 1, which shows a valve of the air bag shown in FIG. 1;

FIG. 3 is a plan view showing one embodiment of an air bag disclosed herein;

FIG. 4 is a perspective view showing one embodiment of an air bag disclosed herein;

FIG. 5 is a vertical sectional view taken along the line C-C′, which illustrates a valve while and after the process of injecting air to the air bag shown in FIG. 4 is executed;

FIG. 6 is a perspective view showing another embodiment of an air bag disclosed herein;

FIG. 7 is a sectional view taken along the line B-B′, which illustrates expansion of an air introduction channel and widening of a first passage by the thermal bonding portion shown in FIG. 6; and

FIG. 8 is a plan view showing another embodiment of an air bag disclosed herein, to which a cock is mounted.

REFERENCE NUMERALS OF ESSENTIAL PARTS IN THE DRAWINGS

100: air bag                     101: air input channel
103: air pillar                  105: outer sheet
120: valve                       121: inner sheet
140: heat resistance ink         125A: first passage
125B: second passage             131-134: thermal bonding line
151, 152: thermal bonding portion 139: thermal bonding point
160: pressurization space        170: cock

BEST MODE

Hereinafter, preferred embodiments of the present invention will be described. While the present invention is described with reference to embodiments thereof, the technical idea and the construction and operation of the invention are not limited to the embodiments.

FIG. 3 is a plan view showing one embodiment of an air bag disclosed herein, and FIG. 4 is a perspective view showing one embodiment of an air bag disclosed herein.

As shown in FIGS. 3 and 4, an air bag 100 of this embodiment includes two outer sheets 105 (see FIG. 5), two inner sheets 121 (see FIG. 5) that forms a valve 120, and a first thermal bonding line 131 and a second thermal bonding line 132 that form an air input channel 101. Also, the air bag of this embodiment includes a third thermal bonding line 133 perpendicularly extending from the second thermal bonding line 132 to form an air pillar 103, a fourth thermal bonding line 134 for elongating a passage of air passing through the valve 120 to improve sealing, and a second thermal bonding portion 152 for forming a pressurization space 160 between the second thermal bonding portion 152 and the second thermal bonding line 132. The air bag of this embodiment also includes a heat resistance ink 140 applied to any one of facing surfaces of the two inner sheets 121. The heat resistance ink 140 is depicted as a dotted line in FIGS. 3 and 4.

In a region of the two inner sheets 121 positioned toward the air input channel 101 with respect to the second thermal bonding line 132, one inner sheet 121 and one outer sheet 105 are bonded and fixed to each other by means of the first thermal bonding point 141.

Here, the fourth thermal bonding lines 134 are formed to cross the third thermal bonding line 133 and thermally bond the two inner sheets 121 to any one of the outer sheets to form an elongated path of air passing through the valve 120. Thus, it is possible to prevent air from being leaked reversely, thereby improving sealing.

The second thermal bonding portion 152 is a thermal bonding region formed with a greater thickness than the first to fourth thermal bonding lines 131, 132, 133, 134, and the second thermal bonding portion 152 has a smaller length than a gap between the third thermal bonding lines 133. Here, a space between the second thermal bonding line and the second thermal bonding portion 152 is a pressurization space 160. The second thermal bonding portion 152 thermally bonds the two outer sheets 105 and the two inner sheets 121.

In a state that the two inner sheets 121 are positioned in the two outer sheets 105, the air input channel 101 is formed by the first thermal bonding line 131 and the second thermal bonding line 132, positioned in parallel with each other. At this time, the second thermal bonding line 132 is formed while passing the heat resistance inks 140 discontinuously formed along the inner sheets 121. Also, the first thermal bonding line 131 bonds just the two outer sheets 105.

The air input channel 101 is formed along the first thermal bonding line 131 and the second thermal bonding line 132 as mentioned above, and one side of the air input channel 101 is closed and the other side is opened. Air is injected through the other side that is open. Meanwhile, the outer sheet 105 and the inner sheet 121 are bonded by the second thermal bonding line 132, but regions where the heat resistance inks 140 are formed are not bonded.

Also, the second thermal bonding portion 152 is formed to cross the third thermal bonding line 133 between the second thermal bonding line 132 and the fourth thermal bonding line 134. FIGS. 3 and 4 show that the second thermal bonding portion 152 is spaced apart from the second thermal bonding line 132, but not limited thereto. The second thermal bonding portion 152 may also be formed continuously from the second thermal bonding line 132. The second thermal bonding portion 152 is located spaced apart from a second thermal bonding portion 152 formed on an adjacent third thermal bonding line 133, thereby forming a second passage 125B through which air may be introduced to the air pillar 103.

FIG. 5 is a vertical sectional view taken along the line C-C′, which illustrates a valve while and after the process of injecting air to the air bag shown in FIG. 4 is executed.

Hereinafter, an air flow while air is injected to the air input channel 101 of the air bag is explained with reference to FIG. 5.

As seen from FIG. 5, if air is injected to the air input channel 101 formed between the first thermal bonding line 131 and the second thermal bonding line 132 using an air injector, the air is injected along the air input channel 101 to expand the air input channel 101.

If the air input channel 101 is expanded as mentioned above, a gap between the two inner sheets 121 is widened, so the air is introduced beyond the second thermal bonding line 132 into the valve 120 between the third thermal bonding lines 133. As the two outer sheets 105 are expanded due to the injected air, the inner sheets 121 respectively bonded and fixed by the first thermal bonding point 141 (see FIGS. 3 and 4) are widened in opposite directions, thereby opening a passage through which air may be introduced.

Meanwhile, the air introduced into the valve 120, namely between the two inner sheets 121, passes through the second passage 125B between the second thermal bonding portions 152 (the second passage 125B is not clearly shown in FIG. 5 since FIG. 5 is a vertical sectional view taken along the line C-C′). After that, the air flows along a path formed by the fourth thermal bonding line 134 and as a result flows into the air pillar 103 through the valve 120.

The air introduced into the air pillar 103 as mentioned above expands the air pillar 103 and increases an inner pressure of the air pillar 103. If the air pillar 103 is expanded, the two inner sheets 121 are closely adhered to any one of the outer sheets thermally bonded by the fourth thermal bonding line 134. At this time, the pressure of air is applied toward the outer sheet to which the two inner sheets 121 are thermally bonded, thereby closing the valve 120. The air pressure is concentrated on a curved region formed just below the location of the second thermal bonding portion 152, than on a flat portion, thereby giving a primary sealing effect.

If the inner pressure of the air pillar 103 is further increased in this state, the air flows into the pressurization space 160 through the second passage 125B of the second thermal bonding portions 152. Also, the air introduced into the pressurization space 160 presses the two inner sheets 121 in the pressurization space 160 toward any one of the outer sheets, thereby giving a secondary sealing effect. Here, the air pressure is more concentrated on a curved region of the outer sheet expanded by a thermally bonded region, such as a region below the second thermal bonding line 132 and above the second thermal bonding portion 152, than on a flat portion of the expanded outer sheet 105.

It is because the curved region has a larger surface area than the flat portion, so pressure is more greatly applied to the curved region. Thus, sealing is more excellent as there are more curved regions. In this principle, as the valve 120 is expanded by air, the second thermal bonding portion 152 may further improve a sealing property by forming more curved regions where air pressure is concentrated.

In other words, in the air bag 100, before the air filled in the air pillar 103 passes through the second passage 125B as the second thermal bonding portion 152 is formed, namely below the second thermal bonding portion 152, the two inner sheets 121 are primarily pressed to any one of the outer sheets for sealing, and then, after the air passes through the second passage 125B, the two inner sheets 121 are secondarily pressed to any one of the outer sheets in the pressurization space 160 for sealing, thereby giving a double sealing structure. According to the double sealing structure, it is possible to minimize leakage of air filled in the air pillar 103.

FIG. 6 is a perspective view showing another embodiment of an air bag disclosed herein.

In the air bag 100 of this embodiment, a heat resistance ink 140 is continuously applied to an end of an inner side of any one of the two inner sheets 121 in a length direction of the inner sheet. Also, the air bag 100 further includes a first thermal bonding portion 151 that ensures smooth widening of the valve 120. Here, the length direction of the inner sheet means a direction perpendicular to the third thermal bonding line 133, namely a direction perpendicular to a length direction of the air pillar 103.

In detail, the first thermal bonding portion 151 is discontinuously formed between the first thermal bonding line 131 and the second thermal bonding line 132 in correspondence to the third thermal bonding line 133, and it is formed at an end of the inner sheet coated with the heat resistance ink 140. A part of the first thermal bonding portion 151 thermally bonds the two outer sheets 105, and the other part of the first thermal bonding portion 151 thermally bonds the two outer sheets 105 and the two inner sheets 121. Here, a gap between the first thermal bonding portions 151 is called “a first passage 125A”.

Also, the heat resistance ink 140 is continuously applied to an end of the inner sheets 121, and also the second thermal bonding line 132 is formed along the heat resistance ink 140. As the second thermal bonding line 132 is formed along the heat resistance ink 140 as mentioned above, the third thermal bonding line 133 may be connected to any point of the second thermal bonding line 132. Also, a gap between the third thermal lines 133 is opened due to the heat resistance ink 140, so air may be easily injected into the air pillar 103 formed by the third thermal bonding line 133.

A method for making the air bag of this embodiment will be explained in more detail. The two inner sheets 121 are positioned on one outer sheet 105, and the fourth thermal bonding line 134 is formed such that the two inner sheets 121 are fixed to one outer sheet 105. Then, the other outer sheet 105 is placed to cover the two inner sheets 121. Here, the heat resistance ink 140 is located at an inner portion of the overlapped inner sheets.

Then, an air input channel 101 is formed. The air input channel 101 is made by forming the first thermal bonding line 131 and the second thermal bonding line 132. The first thermal bonding line 131 is formed in parallel along a length direction of the valve 120 just by thermally bonding the two outer sheets 105. The second thermal bonding line 132 extends in parallel with the first thermal bonding line 131 continuously along the heat resistance ink 140. At this time, the two inner sheets 121 are not bonded to each other due to the heat resistance ink 140, but the outer sheet 105 is bonded to the inner sheet 121.

In this state, the third thermal bonding line 133, the first thermal bonding portion 151 and the second thermal bonding portion 152 may be formed at the same time by molding or formed in any order according to work conditions. The forming order may be changed.

The third thermal bonding line 133 perpendicularly extends with respect to the second thermal bonding line 132 to form a sealed air pillar 103. Here, the third thermal bonding line 133 formed at a region where the inner sheet 121 is located thermally bonds all of the two inner sheets 121 and the two outer sheets 105, and the third thermal bonding line 133 formed at a region where the inner sheet 121 is not located thermally bonds only the two outer sheets. The third thermal bonding line 133 formed at a region where the heat resistance ink 140 is located bonds only the inner sheet 121 and the outer sheet 105 due to the heat resistance ink 140 but does not bond the inner sheets 121 with each other.

Meanwhile, the first thermal bonding portion 151 is formed between the first thermal bonding line 131 and the second thermal bonding line 132, namely at the air input channel 101, and the first thermal bonding portion 151 is formed at an end of the inner sheet 121 in correspondence to the third thermal bonding line 133, namely at an end where the heat resistance ink 140 is applied. Thus, a part of the first thermal bonding portion 151 located at an inner side of the heat resistance ink 140 thermally bonds the inner sheet 121 to the outer sheet, and the other part of the first thermal bonding portion 151 located at an outer side of the inner sheet 121 thermally bonds only the outer sheets 105. Here, a gap between the first thermal bonding portions 151 is the first passage 125A.

One end of the air input channel 101 is closed, and the other end of the air input channel 101 at an opposite side to the air pillar 103 where the valve 120 is positioned is closed. Thus, as air is introduced into the air pillar 103 through the valve 120, the air pillar 103 is expanded.

FIG. 7 is a sectional view taken along the line B-B′, which illustrates expansion of the air introduction channel and widening of the first passage by the thermal bonding portion shown in FIG. 6. If the air input channel 101 is expanded, the two inner sheets 121 are respectively bonded to the outer sheet 105 by the first thermal bonding portion 151 to widen a gap between the two inner sheets 121, thereby forming the first passage 125A. The air is introduced through the first passage 125A over the second thermal bonding line 132 into the valve 120 between the third thermal bonding lines 133. While air is introduced through the first passage 125A, a direction in which the first passage 125A is expanded is identical to a direction in which the valve 120, namely the two inner sheets 121, is widened. In other words, in this embodiment, the first passage 125A does not form an oval shape in which a major axis is longer than a minor axis, but is widened in a substantially circular shape since the expanding direction of the first thermal bonding portions 151 is identical to the widening direction of the first passage 125A. Thus, a pressure applied to the first passage 125A exerts a pressure to open the valve 120, so the valve is smoothly opened by the first passage 125A.

Components that may be added to the air bag of this embodiment will be explained in detail.

Thermal bonding points 139 are formed with intervals in a direction perpendicular to the air pillar 103 in the middle of the air pillar 103 in its length direction. The thermal bonding points 139 play a role of a folding line along which the air pillar 103 may be folded. At least one thermal bonding point 139 may be formed per one air pillar. Particularly, two or three thermal bonding points 139 may be formed per one air pillar 103.

In a general air bag 10, a folding line 17 is formed in a width direction of the air pillar 13. The folding line 17 does not entirely close the air pillar 13 such that air may flow in the air pillar 13, but the folding line 17 reduces an inner space of the air pillar 13, so the air pillar 13 may be easily folded with respect to the folding line 17. This folding line 17 should be positioned at a width center of the air pillar 13. If the folding line 17 leans in one direction, an inner space in an opposite side is wider, so it is difficult to fold the air pillar 13.

However, if the air bag 10 is pushed from its accurate location when the folding line 17 is formed, the folding line 17 may be frequently biased in one side, not located at a width center of the air pillar 13.

In accordance with this embodiment, at least one thermal bonding point 139 bonded to have a substantially circular shape is formed per one air pillar 103 of the air bag 100. Two thermal bonding points 139 may be formed at regular intervals per one air pillar 103. The thermal bonding points 139 are formed in the air pillars 103 without occupying a large area, differently from a general folding line 17. Thus, even when the air bag 100 is pushed while the thermal bonding points 139 are formed, the inner space of the air pillar 103 may be more uniformly reduced. In this way, the air pillar 103 may be easily folded due to the thermal bonding points 139.

FIG. 8 is a plan view showing another embodiment of an air bag disclosed herein, to which a cock is mounted. The air input channel 101 explained above has one closed side and the other open side, so an air injector is inserted into the other open side to inject air therein. However, as shown in FIG. 8, it is also possible that both ends of the air input channel 101 are closed, but a cock 170 is formed in any one of the outer sheets 105 corresponding to the air input channel 101. In this case, an air injector is closely adhered to the cock 170 and then injects air into the air input channel 101.

INDUSTRIAL APPLICABILITY

The air bag disclosed herein ensures an excellent sealing property and high productivity, so it may be used for packaging various articles.

Claims

1. An air bag, comprising:

two inner sheets positioned to face each other;

two outer sheets respectively located at an outer side of the two inner sheets;

a heat resistance material located at an inner side of the two inner sheets and applied to any one of the inner sheets;

a first thermal bonding line for thermally bonding the two outer sheets to form an air input channel;

a second thermal bonding line for thermally bonding the inner sheets and the outer sheets along the heat resistance material with a gap from the first thermal bonding line; and

third thermal bonding lines extending from the second thermal bonding line in a direction opposite to the air input channel to form air pillars,

wherein a second thermal bonding portion is formed at the third thermal bonding lines in a crossing direction thereof to thermally bond the two inner sheets and the two outer sheets such that a pressurization space is formed between the second thermal bonding portion and the second thermal bonding line, and the second thermal bonding portion is spaced apart from a second thermal bonding portion extending from another adjacent third thermal bonding line to form a second passage.

2. The air bag according to claim 1,

wherein fourth thermal bonding lines with a length smaller than an interval between the third thermal bonding lines extend from the third thermal bonding lines in a lateral direction, and

wherein the fourth thermal bonding lines thermally bond the two inner sheets to any one of the outer sheets, and the fourth thermal bonding lines are formed at an opposite side to the second thermal bonding line with respect to the second thermal bonding portion.

3. The air bag according to claim 1, wherein the heat resistance material is continuously applied to the inner sheets in a length direction, and the second thermal bonding line thermally bonds the inner sheets and the outer sheets along the heat resistance material.

4. The air bag according to claim 1,

wherein a plurality of first thermal bonding portions are formed in the air input channel in correspondence to the third thermal bonding lines, respectively, such that adjacent first thermal bonding portions are spaced apart from each other to form a first passage, and

wherein a part of the first thermal bonding portions thermally bond the two outer sheets, and the other part of the first thermal bonding portions thermally bond the outer sheets to the inner sheets.

5. The air bag according to claim 1, wherein at least one thermal bonding point for thermally bonding the two outer sheets in a direction perpendicular to the air pillars is formed at a middle of each air pillar in a length direction thereof.

6. The air bag according to claim 1, wherein both ends of the air input channel are closed, and a cock is formed at any one of the outer sheets corresponding to the air input channel.