GB2350334A

GB2350334A - Side airbag

Info

Publication number: GB2350334A
Application number: GB0012697A
Authority: GB
Inventors: Kazuyuki Inomata
Original assignee: Nihon Plast Co Ltd
Current assignee: Nihon Plast Co Ltd
Priority date: 1999-05-26
Filing date: 2000-05-24
Publication date: 2000-11-29
Anticipated expiration: 2020-05-24
Also published as: JP3411524B2; GB0012697D0; JP2000335350A; GB2350334B

Abstract

An airbag apparatus for a passenger seated in a seat of a vehicle has an inflator generating gas and a folded-up airbag body. Gas from the inflator causes to the airbag body to inflate. The airbag body has a first outer base cloth 21 opposing a passenger, a second outer base cloth 22 opposing an inner side wall of the vehicle, an inner base cloth 23 or 24 on an inside surface of at least one of the first and second outer base cloths, and at least one communicating hole 25 or 26 formed in the inner base cloth. The first outer base cloth and the second outer base cloth are formed as a bag. A bulkhead 33 is provided between the head protecting part and the thorax protecting part. A tether 29 and with a fire protection cloth 30 is provided between the first and second base cloths.

Description

2350334 1 SIDE AIRBAG APPARATUS FOR A VEHICLE

BACKGROUND OF THE INVENTION

The present invention relates to a side alrbag apparatus for a vehicle which inflates instantly when another vehicle collides with the side of the vehicle, o3; when the vehicle collides with an obstruction such as a utility pole, in a so-called side collision, and which protects a passenger by entering between the passenger and an inner side wall of the vehicle. In an airbag described in Japanese Unexamined Patent Application publication H10-287195 an airbag body is normally housed in a folded up condition within a seat back, and inflates by means of gas from an inflator when the vehicle is subjected to a side collision. The inflated airbag body deploys outside the seat back in a space between the passenger and an inner side wall of the vehicle, and absorbs the shock when a secondary collision of the passenger occurs with the side wall. For this reason, relative to the alrbag body capacity, it is necessary to have a high- output inflator. The airbag body has an exhaust hole, which enables quick exhausting of the gas from within the airbag after inflating. A heat- resistant synthetic resin coating is applied to the inner surface of the airbag body.

SUMMARY OF THE INVENTION

The heat-resistant synthetic resin coating on the inner surf ace of the alrbag body, however, not only causes a signif icant increase in the cost of the airbag body, but also leads to an increase in its weight.

Accordingly, in consideration of solving the above-noted problems in the past, it is an object of the present invention to provide a reduced-cost, lightweight vehicular airbag apparatus 5 that maintains its gas exhausting function.

To achieve the above-noted object, a side airbag apparatus for a vehicle passenger seated in a seat has an inflator that generates gas and a folded-up airbag bq.dy. Gas from the inflator causes the alrbag body to inflate. The airbag body has a first outer base cloth that opposes the passenger, a second outer base cloth that opposes an inner side wall of the vehicle, an inner side base cloth on the inner surface of at least one of the first and second outer base cloths, and a communicating hole formed in the inner side base cloth. The f irst outer base cloth and the second outer base cloth are formed as a bag.

In the above-noted conf iguration, af ter a high- temperature gas from the inflator is received by the inner side base cloth, the gas comes into contact with the first and second outer base cloths. Because of this, even if the first and second outer cloths are not treated with a heat-resistant synthetic resin coating, the first and second outer cloths are not affected by the gas. Furthermore, because the first and second outer base cloths do not require the application of a heat-resistant synthetic resin coating, it is possible f or gas to be exhausted from the spaces between the fibers of the first and second outer base cloths that form the alrbag body. For this reason, the airbag body has the function of gas exhausting and, to the extent that it is not coated with a heat-resistant synthetic resin, it has a reduced cost and reduced weight.

2 The above-noted airbag body can have a thorax- protecting part with a built-in inflator, and a head-protecting part disposed downstream from the thorax -protecting part, and the inner side base cloth with the communicating hole can be disposed at least 5 on the thorax-protecting part.

According to the above-noted configuration, because the inner side base cloth having a communicating hole is disposed on at least the thoraxprotecting part, tie exhausting of gas from the inflator is enhanced. For this reason, there is a reduction in the f orce of repulsion imparted to the passenger f rom the airbag body, with no excessive inflation of the thorax-protecting part.

The communicating hole can be in proximity of the headprotecting part, and can be at a distance from the Inflator.

The temperature of the high- temperature gas when It has just been discharged from the inflator gradually decreases with increasing distance from the inflator. In the above-noted configuration, the communicating hole is provided at a position so that gas is permitted to pass therethrough after sufficient inflation of the thorax- protecting part. For this reason, it Is possible to make the temperature of the exhausted gas the desired temperature, while maintaining the inflation function of the thorax-protecting part.

A wall-shaped f ire-protection member can be disposed on the inner surface of the inner side base cloth between the communicating hole and the inflator.

According to the above-noted configuration, hightemperature gas discharged from the inflator interferes with the wall-shaped f Ire- protection member, so that the gas that does not directly flow into the communicating hole contributes to a 3 reduction in the gas temperature.

There can be a plurality of communicating holes.

According to the above-noted configuration, because of the distribution of high-temperature gas to a plurality of holes, compared to the case in which the gas is concentrated, the gas temperature is lower, and there is a significant reduction of the danger of the heating of the inner side wall of the vehicle.

The inner side wall with the c.qmmunicating holes can be p.,,' disposed on an inner surface of the second outer base cloth.

According to the above-noted configuration, because the second outer base cloth is in opposition to the inner side wall of the vehicle, the passenger is not exposed to a hot blast of gas discharged from the inflator.

BRIEF DESCRIPTION OF THE DRAWINGS.

Fig. 1 is an overall perspective view of a seat in the condition in which the airbaq body of a vehicular side airbag apparatus according to an embodiment of the present invention has inflated.

Fig. 2 is a cross-section view along the line SA-SA, showing the airbag body of the vehicular airbag apparatus of Fig. 1 bef ore inflation.

Fig. 3 ls a side elevation of the airbag apparatus of Fig.

1.

Fig. 4 is a cross-section view along the line SB-SB of Fig.

3.

Fig. 5 is an exploded perspective view of the airbag apparatus of Fig. 3.

4 DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are described in detail below, with reference made to relevant accompanying drawings.

Fig. 1 to. Fig. 5 show an embodiment of the present invention.

As shown in Fig. I and Fig. 2, a seat 1 is formed by a seat back 2 and a seat cushion 3. A side airbag apparatus 5 is disposed at a position of the seat back 2 that is opposite the inner side wall of the vehicle.

The seat back 2 has a seat back frame 6, a main cushion 7 disposed at the f ront frame part FR of the seat back f rame 6, a side cushion 8 disposed at the side frame part SD of the seat back frame 6, outer coverings 9 and 10 covering main cushion 7 and the side cushion 8, and a rupturing part 11, which is sewn together and enables rupture of the outer coverings 9 and 10.

The side airbag apparatus 5 has a tubular holder 13 housing within it an inflator 12 that is ignited by a signal from a sensor or the like (not shown in the drawing), an airbag body 16 disposed so that an inlet part 15 thereof f aces the discharge port 14 of the holder 13, which is normally folded up, and which inflates by a gas that is discharged from the inflator 12, and a case 18 positioned having a rupture part 11 in a position that opposes an opening part 17 rupturing with the j_nf lation of the airbag body 16.

The holder 13 is f ixed to the seat back f rame 6 by a stud bolt 19 inserted together with a folded back end of the introduction part 15 of the airbag body 16 and a nut that mates with the stud bolt 19. In this condition, the discharge port 14 of the holder 13 faces the above-noted front frame part FR.

The airbag body 16 has a first outer base cloth 21 opposing passenger (in the compartment) and a second outer base cloth 22 opposing an inner side wall 4 of the passenger compartment. The first and second outer base cloths 21 and 22 are formed as a bag (with the sewn together parts indicated as H7), are normally folded up, and inflate by gas from the inflator 12 that is internally housed.

Along the inner surface of the f--.4rst and second outer base cloths 21 and 22, are disposed first and second inner base cloths 23 and 24. The f irst and second inner base cloths 23 and 24 have formed in them communicating holes 25 and 26 which cause efficient exhausting of gas from the inflator 12. The first and second outer base cloths 21 and 22 are both substantially L-shaped. The first and second outer base cloths 21 and 22, the first and second inner base cloths 23 and 24, and the second fire-protection cloth 31 to be described below have formed in them holes 34 and 35 for accepting the stud bolt 19.

The alrbag body 16 has a thorax- protecting part 27, within which is housed the inflator 12, and a head-protecting part 28, which is positioned downstream from the thorax- protection part 27. The first and second inner base cloths 23 and 24, in which are f ormed the communicating holes 25 and 26, are disposed at least on the thorax-protecting part 27.

The communicating holes 25 and 26 of the f irst and second inner base cloths 23 and 24 are in proximity to the head-protecting part 28 or at a distance from the inflator 12. In this embodiment of the present invention, the communicating holes are a plurality of holes (in this embodiment, in four locations), the diameter of one of the communicating holes 25 and 26 being approximately 6 mm, although the shape, size and number of communicating holes 25 and 26 can be established as appropriate to the capacity of the airbag body 16 and the performance of the inflator 12.

A tether strap 29 is provided on the end parts of the -inner surfaces of the first and second outer base cloths 21 and 22. On the inner surfaces of the first and second inner base cloths 23 and 24 are provided wall-shaped fire-protection members in the form of a first fire- protection cloth 30, between the communicating holes 25 and 26 and the holder 13, to be described below. A second f ire-protectlon cloth 31 is disposed on the inner surface of the second inner base cloth 24. In this embodiment, although a heat-resistant synthetic resin (for example, a silicone coating) is provided on one surface of the first and second fireprotection cloths 30 and 31 so as to enhance heat resistance, it is alternately possible to use a non-coated f abr1c, depending upon the performance of the inflator 12. The first and second outer base cloths 21 and 22 are non-coated fabric.

A bulkhead 32 is provided a center region of the first and second outer base cloths 21 and 22 of the alrbag body 16. The thorax- protecting part 27 is disposed below the bulkhead 32 and the head- protecting part 28 is disposed above the bulkhead-32, the bulkhead 32 serving to make a division between the protecting parts 27 and 28. A single or a plurality of communicating holes 33, whereby the thorax- protecting part 27 and the head-protecting part 28 are joined, are formed in the bulkhead 32. The bulkhead 32 can either have a coating of a heat-resistant synthetic resin, such as silicone, or be a non-coated fabric.

In this embodiment of the present invention, although the communicating holes 25 and 26 are formed in the first and second 7 inner base cloths 23 and 24, it is alternately possible to form them in only the second inner base cloth 24. The overall surface area of the communicating hole 26 can be made greater than the communicating hole 25 formed in the first inner base cloth 23.

A methoa7f or manuf acturing the airbag body 1 6 is as follows.

First, a mounting hole 34 for the stud bolt 19 is formed in the first outer base cloth 21 that has been cut out. Next, in a first inner base cloth 23 cut out to the sc-gne shape as the thorax protecting part of the first outer ba se cloth 21, is formed a mounting hole 34 for the stud bolt 19. A first inner base cloth 23 is superposed on the f irst outer base cloth 21, which will serve as the inside of the airbag body 16 when it is completed, and the end parts near the insertion part 36 of the holder 13 are sewn together when the airbag body is completed (the sewn together parts being indicated as H1).

In the same manner, a mounting hole 35 for the stud bolt 19 is f ormed in the second outer base cloth 22 that has been cut out. Next, a mounting hole 35 for the stud bolt 19 is formed a second inner base cloth 24, which is cut out to the same shape as the thorax -protecting part of the second outer base cloth 22.

A second inner base cloth 24 and second f ire-protection cloth 31 are superposed on the second outer base cloth 22, which will serve as the inside of the airbag body 16 when it is completed, and the end parts near the insertion part 36 of the holder 13 are sewn together when the airbag body is completed (the sewn together parts being indicated as H1).

The insides of the first and second outer base cloths 21 and 22 formed as described above are superposed, a bulkhead 32 is disposed between the thorax-protecting part 27 and the 8 head-protecting part 28, and the bulkhead 32 is sewn to the first and second outer base cloths 21 and 22, the sewn together parts being indicated as H2 and H3.

A tether strap 29 for holding the shape of the first outer base cloth 21 and the second outer base cloth 22, and a first fire-protection cloth 30 for protecting the tether strap 29 from high- temperature gas from the inflator 12 are sewn to the inner surfaces of the first and second outer base cloths 21 and 22 s:. ' beforehand, the sewn together parts being indicated as H4, H5, 10 and H6. Finally, the edges of the first and second outer base cloths are sewn together, the sewn together parts being indicated as H7.

The first and second outer base cloths 21 and 22, the first and second inner base cloths 23 and 24, the tether strap 29, the first fireprotection cloth 30, and the bulkhead 32 are made of non-coated 420 denier Nylon 66, having a weight of 210 g/M2.

Ventilation by the Frazier method is 0. 7 CC/CM2/S. The first and second inner base cloths 23 and 24, the tether strap 29, and the first fireprotection cloth 30 need not be coated, and can alternately be a fabric with a laminated layer of rubber or synthetic resin, for example, so as to prevent ventilation.

In the above-described embodiment of the present invention, the inf lator 12 is ignited by some form of signal responsive to a collision of the vehicle, and gas is discharged from the discharge port 14 of the holder 13, thereby causing the airbag body 16 to inf late. The airbag body 16 causes deformation of the f ront f rame part FR of the case 18 in the opening direction, the opening 17 of the case 18 opening, and the airbag-body 16 then further inflating. The f orce of inflation causes a concentration of stress at the rupture part 11 of the seat back 2. The rupture 9 part 11 thus ruptures, so that as shown in Fig. 1, the airbag body 16 inflates toward the outside.

In the airbag body 16, high-temperature gas from the inflator 12 is first received by the first and second inner base cloths 23 and 24. For this reason, the first and second outer base cloths 21 and 22, even though they are not treated with a heat -resistant synthetic resin coating, are not inf luenced by the high- temperature gas. Furthermore, begause the first and second outer base cloths 21 and 22 are not treated with a heat-resistant synthetic resin coating, it is possible for gas to be exhausted through the spaces between the f ibers of the f irst and second outer base cloths 21 and 22. For this reason, the a:Lrbag body 16 maintains its gas exhausting function, while featuring a reduced cost and light weight, by virtue of not providing a heat-resistant synthetic resin coating.

Because the f irst and second inner cloths 23 and 24, in which are f ormed the communicating holes 25 and 26 are disposed at least on the thoraxprotecting part 27, such abnormal inflation of the airbag body 16, such as nearly spherical inflation, is prevented, exhausting is enhanced, and the thorax-protecting part 27 reduces the force of repulsion with respect to the passenger.

The high- temperature gas that has just been discharged from the inflator 12 interferes with the wall-shaped first fire- protection cloth 30, and does not flow directly into the communicating holes 25 and 26. For this reason, when the gas flows into the communicating holes 25 and 26, the gas temperature is reduced. The f arther is the position of the communicating holes 25 and 26 from the inflator 12, the greater is the reduction in the temperature of the gas. In this embodiment, because the communicating holes 25 and 26 are positioned so as to permit gas to pass therethrough after sufficient inflation of the thorax-protecting part 27, it is possible to achieve a preferred temperature of the exhausted gas, while maintaining the inflation 5 function of the thorax-protecting part 27.

Because the high-temperature gas is distributed among a plurality of communicating holes 25 and 26, compared to the case in which the gas is concentrated, the.9as temperature is lower, and there is a significant reduction of the danger of the heating of an inner side wall 4 of the vehicle.

It will be understood that the present invention is not restricted to the above-described embodiment. For example, it is possible to have a configuration in which communicating holes 25 are not formed on the first inner base cloth 23, a communicating hole 26 being formed on the second inner base cloth 24 only. In this case, because a hot blast is exhausted from only the second outer base cloth 22, the passenger is not exposed to a hot blast of gas discharged from the inflator 12.

Additionally, it is possible to extend the first and second inner base cloths to the head-protecting part 28, and to provide a communicating hole near the top part of the head-protecting part 28. In this case, because the position of exhausted gas is higher than the position of the head of the passenger and at the side window panel, there is a significant reduction in the danger of heat damage occurring within the passenger compartment of the vehicle. It is further possible to have first and second outer base cloths 21 and 22 that are not substantially L-shaped, but rather that are shaped simply to protect the thorax (torso).

Claims

What is claimed is:

1. A side airbag apparatus for a passenger seated in a seat of a vehicle, comprising: 5 an inflator generating gas; a f olded-up aIrbag body inflated by gas from the inflator, wherein the airbag body comprises: first outer base cloth opposite a passenger; second outer base cloth oppoilte an inner side wall of the vehicle, the f irst outer base cloth and second outer base cloth being formed as a bag; an inner base cloth on an inner surface of at least one of the first and second outer base cloths, in which is formed a communicating hole.

2. A side airbag apparatus according to claim 1, wherein the airbag body comprises a thorax -protecting part internally housing the inflator, and a head- protecting part disposed downstream from the thorax-protecting part, and wherein the inner base cloth having the communicating hole is disposed on at least the thorax- protecting part.

3. A side airbag apparatus according to claim 2, wherein the communicating hole is near the thorax-protecting part.

4. A side airbag apparatus according to claim 1, wherein the communicating hole is distant from the inflator.

5. A side airbag apparatus according to claim 1, further 12 comprising a wall-shaped fire-protection member disposed on the inner base cloth between the communicating hole and the inflator.

6. A side airbag apparatus according to claim 1, wherein the communicating hole is a plurality of holes.

7. A side airbag apparatus., according to claim 1, wherein the inner base cloth having a communicating hole is disposed on an inner surface of the second outer base cloth.

8. A side airbag apparatus according to claim 1, wherein the inner base cloth with the communicating hole is arranged on an inner surface of the first and second outer base cloths.

9. An airbaq for a vehicle, comprising outer layer means for inflation between a passenger and a predetermined portion of said vehicle and a heat shielding member which in use shields the outer layer means from the heat of a gas used to inflate the airbag.

10. A vehicle comprising an airbag apparatus as claimed in any one of claims 1 to 8 or an airbag as claimed in claim 9.

11. An airbag or airbag apparatus substantially as herein described with reference to the accompanying drawings.

13