Airbag device

To provide a technique that is effective for allowing a pressurized fluid to pass through smoothly between a plurality of bag-like bodies when inflated and extend, and for improving their extendibility.An airbag device includes a first bag 35 composed of a bag body formed by joining base fabrics 35A, 35B, and provided with a supply flow passage for supplying a pressurized fluid supplied from an inflator into the inside and a flow-out passage for allowing the pressurized fluid supplied into the inside to flow out to the outside, a second bag 36 composed of a bag body formed by joining base fabrics 36A, 36B, and provided with a flow-in passage for allowing the pressurized fluid allowed to flow out from the flow-out passage of the first bag 35 to flow into the inside, and a connection panel PN for connecting the first bag 35 and the second bag 36 so that the whole of the first bag 35 and the second bag 36 is configured in a predetermined shape when inflated and extends.

TECHNICAL FIELD

The present invention relates to an airbag device equipped in a vehicle such as an automobile and the like.

BACKGROUND ART

Hitherto, there have been used various types of airbag devices, which serve to restrain the body of an occupant in an event of a vehicle collision or the like, such as a driver airbag device that is inflated and extends to the side of a driver from the rotation center of a steering wheel in a driver seat, a passenger airbag that is inflated and extends to the side of a passenger seat from an instrument panel, and the like.

In recent years, airbag devices have been proposed that are applicable to a possible case such that an occupant suffers an impact on his/her head from overhead due to a shock of an eventual big accident, which applies a large force to an automobile, such as a lateral overturn of a vehicle body caused by a collision or the like, a drop of a heavy body like a falling tree, or the like (for example, refer to Patent Document 1).

DISCLOSURE OF INVENTION

Problems to be Solved by the Invention

In the prior art described above, a basic structure is disclosed that an airbag constructed of a bag-like body formed by joining base fabrics together is accommodated in a backrest portion (or a headrest) of a vehicle seat, and is inflated by being provided with a pressurized fluid from an inflator in an emergency situation to extend toward the above of an occupant's head portion.

In such a basic structure, in the case when an airbag is composed of a plurality of bag-like bodies, joint portions that allow a pressurized fluid to pass through between these bag-like bodies are required to allow the pressurized fluid to pass through smoothly between the bag-like bodies when inflated and extend.

An object of the present invention is to provide a technique that is effective for allowing a pressurized fluid to pass through smoothly between a plurality of bag-like bodies when inflated and extend, and for improving their extendibility.

Means for Solving the Problems

In order to solve the above object, the first invention of the present application is characterized in that an airbag device includes a first bag composed of a bag body formed by joining base fabrics together, and provided with a supply flow passage for supplying a pressurized fluid supplied from an inflator into the inside and a flow-out passage for allowing the pressurized fluid supplied into the inside to flow out to the outside, a second bag composed of a bag body formed by joining base fabrics together, and provided with a flow-in passage for allowing the pressurized fluid allowed to flow out from the flow-out passage of the first bag to flow into the inside, and a connection member for connecting the first bag and the second bag so that the whole of the first bag and the second bag is configured in a predetermined shape when inflated and extends.

According to the first invention of the present application, since the first bag and the second bag are connected by the connection member, the flexibility of extension movement of the first bag and the second bag is restricted by the connection member and their extension directions are guided in fixed directions when the airbag is inflated and extends. As the result, the extension ability of the entire airbag can be improved.

The second invention of the present application is characterized in that, in the first invention, the connection member connects a connection portion for the first bag connected to the one side of the first bag, and a connection portion for the second bag connected to the other side of the second bag when inflated and extends.

According to the second invention of the present application, since the connection member is connected to the one side of the first bag by the connection portion for the first bag, and is also connected to the other side of the second bag by the connection portion for the second bag when inflated and extends, the first and second bags at the time when inflated and extends are allowed to extend in a good balance without unbalanced when inflated and extends.

The third invention of the present application is characterized in that, in the second invention, the connection portion for the second bag of the connection member is provided with a plurality of pairs, which are located different positions in a vehicle width direction with each other, each of the pairs being positioned in left and right sides of the center line in the vehicle width direction.

According to the third invention of the present application, the second bag when inflated and extends can extend in a state that a vehicle width direction connected by a plurality of pairs with each other, each of the pairs being positioned in left and right sides of the center line in the vehicle width direction is restricted by the connection portion for the second bag.

The fourth invention of the present application is characterized in that, in the third invention, the connection member is composed of a fabric body.

According to the fourth invention of the present application, since the connection member is composed of a fabric body, the first bag and the second bag can extend as being guided in mutually fixed directions. In addition, when accommodated in a retainer, the connection member can also be accommodated in a state of being folded together with the first bag and the second bag.

The fifth invention of the present application is characterized in that, in the fourth invention, the connection member is composed of a non-inflatable fabric body.

According to the fifth invention of the present application, since the connection member is composed of a non-inflatable fabric body, the first bag and the second bag can be guided in fixed directions in a state that the positioning relationship therebetween is mutually restricted, when the airbag is inflated and extends.

The sixth invention of the present application is characterized in that, in any one of the first to fifth inventions, the first bag includes a pushing extension portion being inflated and extending by the pressurized fluid supplied from the inflator, the pushing extension portion being provided with a extension deriving portion for deriving the second bag to the above of the head portion of the occupant, and the second bag includes an upper extension portion, which is inflated and extends toward the above of the head portion of the occupant.

According to the sixth invention of the present application, when the pressurized fluid is supplied from the inflator, the pushing extension portion of the first bag is inflated, and at the time of inflation, the extension of the second bag is promoted to allow the upper extension portion of the second bag to be inflated and extend toward the above of the head portion of the occupant; thereby the head portion of the occupant can be restrained from moving upward.

The seventh invention of the present application is characterized in that, in the sixth invention, the pushing extension portion of the first bag is inflated and extends on the side facing the back of an occupant's head, and the second bag is provided with a lower extension portion, which is inflated and extends on the side opposite with respect to the occupant and is disposed to overlay the pushing extension portion.

According to the sixth invention of the present application, since the pushing extension portion of the first bag is inflated and extends on the side facing the back of the occupant's head, and the second bag is provided with the lower extension portion, which is inflated and extends on the side opposite with respect to the occupant and is disposed to overlay the pushing extension portion, it becomes possible to change the posture of the back of an occupant's head to lean forward effectively due to the thickness of the two portions of the pushing extension portion and the lower extension portion.

Advantages

According to the present invention, it becomes possible to provide a technique that is effective for allowing a pressurized fluid to pass through smoothly between a plurality of bag-like bodies when inflated and extends, and for improving their extendibility.

REFERENCE NUMERALS

2occupant2A head portion10airbag device11airbag13inflator20pipe member35first bag35A first base fabric35B second base fabric35agas supply port (supply flow passage)35tflow-out passage36second bag36A third base fabric36B fourth base fabric36iflow-in passage37pushing extension portion39upper extension portion40sewn joint portion (connection portion for the second bag)40b,40csewn joint portions (connection portions for the first bag)50lower extension portion90extension deriving portionPN connection panel (connection member)SC sewn joint portion (connection portion for the second bag)SL, SR sewn joint portion (connection portion for the first bag)

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1are schematic side views of a vehicle seat1equipped with an embodiment of an airbag device of the present invention, whereinFIG. 1(a) shows a non-activated state of the airbag device andFIG. 1(b) shows an activated state of the airbag device. The above seat (seat)1is provided with a seated portion1A on which an occupant2is seated, and a backrest portion1B projecting upward from the seated portion1A, the backrest portion1B being for supporting the seated occupant2. On an apex portion of the backrest portion1B, a headrest1C is mounted.

The seat1is provided with an airbag device10for restraining the head portion2A of the occupant2in an occasion of a lateral overturn of a vehicle body caused by an accident, or the like in the backrest portion1B. The airbag device10is constituted of a first bag35(refer toFIGS. 5 and 6, described later) formed by joining a first base fabric35A and a second base fabric35B by sewing together, a second bag36(refer toFIGS. 5 and 7, described later) formed by joining a third base fabric36A and a fourth base fabric36B by sewing together, a connection panel PN described later, which becomes a connection member connecting these first bag35and second bag36with each other, and a flow-passage connecting member60(refer toFIGS. 4 and 12, described later) joining the first bag35and the second bag36, and is provided with an airbag11configured so as to extend toward the above of the head portion2A of the occupant2when inflated, a retainer12in which the airbag11is accommodated in a state of being folded, and an inflator13(refer toFIGS. 2 and 3) supplying gas (pressurized fluid) for inflating and extending the airbag11.

The seat1also has a seat frame14in its inside, which is constructed of side plates14(refer toFIG. 2) and a cross member14B (refer toFIG. 2) and the like, and forms a framework of the seat1; the retainer12and the inflator13are attached to the seat frame14(details are described later).

It is noted that, although not shown, an automobile equipped with an airbag device1is provided with various types of sensors detecting an occurrence (or prediction of an occurrence) of a collision (including a lateral collision or the like) or lateral overturn when such an accident occurs on the automobile. And, an inflator controlling circuit (not shown) activates an initiator (not shown) of the inflator13according to a detection signal from the sensors.

As shown inFIG. 1(a), the airbag11is accommodated in the retainer12in a state of being folded in a normal situation. On the other hand, in an event that, for example, the automobile comes into collision or laterally overturns, or the like, the sensors described above detect it and an activating signal is input from the inflator controlling circuit to the initiator of the inflator13; thereby the initiator is activated to inflate the airbag11and extend it toward between the roof3of the automobile and the head portion2A of the occupant2as shown inFIG. 1(b) (it is noted that, in the case of an open car or the like having no roof3, the airbag11extends toward the above of the head portion2A). At this time, the airbag11is inflated so as to push the head portion2A of the occupant2forward due to that a pushing portion (refer toFIGS. 4 and 5)of the first bag35and a lower portion (refer toFIGS. 4 and 6) of the second bag36are inflated and extend, and thereby the head portion2A of the occupant2is leaned forward, which causes the load applied to the neck portion to be reduced.

FIG. 2is a perspective view showing a structure for fixing the airbag device10to the seat frame14, andFIG. 3is an exploded perspective view of the airbag device showing the fixing structure more in detail.

In theseFIG. 2andFIG. 3, the seat frame14includes a pair of side plates14A,14A provided on the both sides in a vehicle width direction (both sides in the left and right direction inFIG. 2) in the backrest portion1B of the seat1, and the cross member14B extending along substantially a vehicle width direction between the side plates14A,14A and connecting the side plates14A,14A. The side plates14A,14A and the cross member14B are all mounted in the backrest portion1B of the seat1. It should be understood that, although not shown, the seat frame14also includes a base plate provided in the seated portion1A.

On the base end side (inflator side, lower side inFIG. 3) of the airbag11, there are provided a gas supply port (supply flow passage)35a(refer toFIG. 4toFIG. 6) connected to the inflator13via a pipe member20, and attachment pieces35b,35b(refer toFIG. 4toFIG. 6) located on both sides of the gas supply port35a. In each of the attachment pieces35b,35b, there are provided two bolt holes22for inserting through attachment bolts21a(refer toFIG. 3) for fixing the airbag11and the retainer12by being punched.

On the other hand, the retainer12is provided with attachment portions12a,12b, in each of which a bolt hole24for inserting through an attachment bolt23is provided by being drilled, on its both sides in a vehicle width direction, and an attachment portion12c, in which bolt holes25are also provided by being drilled in positions corresponding to the bolt holes22in the airbag attachment portions35b, in its lower portion (inflator side, lower side inFIG. 3).

The plurality (4 pieces in this embodiment) of attachment bolts21aare inserted through the bolt holes25formed in the retainer attachment portion12c, the bolt holes22in the airbag attachment portions35b, and bolt holes27formed in positions corresponding to the bolt holes22in the airbag attachment portions35bin a state that the airbag11is folded and accommodated in the retainer12, and are joined to nuts21bby being screwed; thereby the airbag11is fixed to the retainer12in a state of being folded.

Likewise, the plurality (2 pieces in this embodiment) of attachment bolt23are inserted through the bolt holes24of the retainer attachment portions12a,12b, and then joined to joining holes (not shown) provided in the cross member14B by being screed; thereby the retainer12in which the airbag11is accommodated in a state of being folded is fixed to the cross member14B.

The pipe member20is a pipe made of, for example, a metal material, being bent at plural portions (2 portions in this embodiment), and is disposed below the retainer12. The pipe member20and the airbag11are connected in a manner such that a bag-side end portion20aof the pipe member20is covered with the gas supply port35aof the airbag11and fixed by being crimped with, for example, a metal clamp band30. Likewise, the pipe member20and the inflator13are connected in a manner such that an upper end portion13aof the inflator13is covered with a connection portion20bprovided on an inflator-side end portion of the pipe member20and fixed by being cemented (or welded). The airbag11and the inflator13are thus connected via the pipe member20.

The inflator13is provided further below the pipe member20and attached to the side plate14A on one side (left side in a vehicle width direction in this embodiment) using an attachment member31. The attachment member31includes a pair of attachment plates31A,31B, which support the inflator13by gripping it therebetween, and the attachment plates31A,31B are fixed with the inflator13gripped therebetween by that a plurality (4 pieces in this embodiment) of rivets31aformed on the attachment plate31A are inserted through a plurality (4 in this embodiment) of rivet holes31bprovided by being drilled in positions corresponding thereto in the attachment plate31B and are connected by being riveted. In addition, the attachment plate31A is provided with an attachment portion31cformed by being bent at substantially 90 degrees on its one side (left side in a vehicle width direction) end portion, and a plurality (2 pieces in this embodiment) of attachment bolts (not shown) are inserted through bolt holes provided by being drilled in this attachment portion31cand joined to joining holes (not shown) provided in the side plate14A by being screwed; the attachment member31is thus fixed to the side plate14A. As the result, the inflator13is fixed to the side plate14A via the attachment member31.

It is noted that the inflator13is connected with a control unit (not shown) described above by a cable34, and ignition control of the inflator13is carried out via the cable34.

FIG. 4is a perspective view showing a general structure of the airbag11in a state of being fully inflated and extending.

In thisFIG. 4, the airbag11is provided with the first bag35, which has a pushing extension portion37and a supporting extension portions38in its inside, and is inflated by being supplied with a pressurized fluid at the start from the inflator13and allows the pushing extension portion37to extend on the side facing the back of an occupant's head, the second bag36, which has an upper extension portion39and a lower extension portion50in its inside, and is inflated by being supplied with the pressurized fluid via the first bag35and allows the upper extension portion39to extend toward the above of an occupant's head portion, while extending the lower extension portion50in an arrangement overlapping with the pushing extension portion37on the opposite side with respect to the occupant, and the flow-passage connecting member60, which joins the first bag35and the second bag36so that the insides thereof are connected to each other. Two flow-out passages35teach formed in the first bag35in a configuration of a pipe-like flow passage and two flow-in passages36ieach formed in the second bag36in a configuration of a pipe-like flow passage are connected to each other by being highly hermetically sealed using the flow-passage connecting member60, respectively (refer toFIGS. 11 and 12).

InFIG. 4, the gas supply port35a(supply flow passage) described above is provided in a lower portion of the first bag35, and the gas blown out from the inflator13shown inFIG. 2is supplied to the pushing extension portion37and then to the supporting extension portions38in the first bag35via the pipe member20and this gas supply port35a. Then, the pressurized fluid is allowed to flow from the two flow-out passages35tlocated on both sides of the gas supply port35ain a lower portion of the first bag35(refer toFIGS. 5,6and12) to the two flow-in passages36ilocated on both sides in a lower portion of the second bag36(refer toFIGS. 7 and 12) and is supplied to the upper extension portion39and the lower extension portion50.

As shown inFIG. 4, the first bag35and the second bag36constitutes the airbag11by connecting flow passages of each of independent two bag bodies35and36, which are formed by sewing together base fabrics on the side of the occupant2(the front side of the vehicle) and base fabrics on the opposite side with respect to the occupant2(the rear side of the vehicle).

FIG. 5is a plan view seen from the side of the second base fabric35B, showing a general structure of the first bag35and the second bag36, joined with each other by being sewn (namely, the second bag36, positioned on the topside of the first bag35, seen from the side of the first bag35), in a state before being inflated and extended (a state before being folded for being accommodated),FIG. 6is a plan view seen from the side of the second base fabric35B (namely, the underside of the first bag35), showing a general structure of the first bag35in a state before being inflated and extending,FIG. 7is a plan view seen from the side of the fourth base fabric36B, showing a general structure of the second bag36in a state before being inflated and extending (a state before being folded for being accommodated),FIG. 8is a developed view of a connection panel,FIG. 9is a cross-section view taken from line A-A ofFIG. 5, andFIG. 10is a cross-section view taken from B-B ofFIG. 5.

InFIGS. 5 and 6, the first bag35is formed as one bag body by joining the first base fabric35A and the second base fabrics35B, which have a substantially identical shape, by sewing the entire periphery thereof except the gas supply port35aand the flow-out passages35t. In the drawings, reference numeral40denotes the sewn joint portion, and reference numeral41denotes a sealing material portion constituted of an appropriate sealing material, which is provided along the sewn joint portion40for sealing the sewn joint portion40.

The second base fabric35B includes the pushing extension portion37having a substantially trapezoidal shape being enlarged from the side of the gas supply port35a(lower side inFIG. 6) toward the opposite side thereof (upper side inFIG. 6) and the pair of supporting extension portions38provided on both left and right sides in an upper portion of the pushing extension portion37in the drawings. The first base fabric35A has a substantially similar shape to the second base fabric35B. Between the first base fabric35A and the second base fabric35B, there are formed the pushing extension portion37, the pair of supporting extension portions38located on both left and right sides of the pushing extension portion37, and the flow-out passages35tby that the first base fabric35A and the second base fabric35B having such the shape are joined together by being sewn around the entire periphery thereof except the gas supply port35aand the flow-out passages35tas described above. As the result, the pushing extension portion37, the pair of supporting extension portions38, and the flow-out passages35tare arranged so that their outer edges are enveloped by the sewn joint portion40and the sealing material portion41on the whole.

The pushing extension portion37has four pushing extension chambers37a,37b,37c,37dformed by a sewn joint portion40a, which is provided in the substantially middle part of the pushing extension portion37substantially along a gas flow-in direction, and sewn joint portions40b,40cprovided on both sides of the sewn joint portion40a(left and right sides inFIG. 6); thereby the gas supplied from the gas supply port35ais allowed to be smoothly introduced toward the downstream side (upper side inFIG. 6) of the pushing extension portion37.

It is noted that, on both left and right sides of the first bag35, there are provided extension deriving portions90,90each having a substantially triangle shape.

InFIG. 6, the first bag35constituted as described above is formed in a manner such that the first base fabric35A and the second base fabric35B are first sewn in the outer peripheral area thereof along the sewn joint portion40in a state of being overlapped, while being sewn along the sewn joint portions40a,40b,40c, and the like of the pushing extension portion37. At this time, at the tip of each of the sewn joint portions40b,40c, there are formed non-inflated portions L, R, which are sewn with circular sewn joint portions SL, SR, respectively, in the periphery thereof.

Next, the supporting extension portions38are each bent so as to be located at a position where it sandwiches both left and right sides of the head portion of the occupant2with respect to the first bag35as shown inFIG. 4, and in order to keep the state and also to promote the extension of the second bag36when being inflated and extending, the extension deriving portions90,90are joined with derived portions91,91(refer toFIG. 7, described later) by sewing together, the derived portions91,91being provided on both sides of the upper extension portion39of the second bag36.

As shown in thisFIG. 7, the second bag36is formed as one bag body by joining the third base fabric36A and the fourth base fabrics36B, which have a substantially identical shape, by sewing the entire periphery thereof except the two flow-in passages36iand by provided with a sealing material41.

The fourth base fabric36B is a substantially rectangular-shaped member extending from the side of the flow-in passages36i(lower side inFIG. 7) toward the opposite side (upper side inFIG. 7), and includes the upper extension portion39in an upper portion in the drawing and the lower extension portion50in a lower portion in the drawing. The third base fabric36A also has a shape substantially similar to the fourth base fabric36B. Between the third base fabric36A and the fourth base fabric36B, there are formed the upper extension portion39of the upper half in the drawing, the lower extension portion50of the lower half in the drawing, and the two flow-in passages36iby that the third base fabric36A and the fourth base fabric36B having such the shape are joined together by being sewn around the entire periphery thereof except the two flow-in passages36ias described above. As the result, the upper extension portion39, the lower extension portion50, and the two flow-in passages36iare arranged so that their outer edges are enveloped by the sewn joint portion40and a sealing material portion41on the whole.

The upper extension portion39and an upper portion of the lower extension portion50has three upper/lower extension chambers39a,39b,39cpartitioned by two sewn joint portions40d,40e, which are provided substantially along a gas flow-in direction in an arrangement dividing the lower extension portion50into substantially three equal portions in its width direction; thereby the gas supplied from the flow-in passages36iis allowed to be smoothly introduced toward the downstream side (upper side inFIG. 7) of the upper extension portions39a,39b,39c. And, in the substantially central portion of the lower extension portion50, there is provided a circular non-inflated portion C, which is sewn with a circular sewn joint portion SC together with a sealing material in the periphery thereof, and a pair of attachment holes are formed in its center.

The second bag36of the above constitution is formed in a manner such that the third base fabric36A and the fourth base fabric36B are first sewn in the outer peripheral area thereof along the sewn joint portion40in a state of being overlapped, while being sewn along the sewn joint portions40d,40e, the upper extension chambers39a,39b,39care next each bent forward so as to extend toward the above of the head portion of the occupant2with respect to the first bag35as shown inFIG. 4, and the derived portions91,91provided on both sides of the upper extension portion39are joined with the extension deriving portions90,90of the supporting extension portions38on both sides of the first bag35(refer toFIG. 5toFIG. 7).

Consequently, the pushing extension portion37of the first bag35and the lower extension portion50of the second bag36are overlaid with each other at the pushing extension portion37and the lower extension portion50. Moreover, in the portion where the pushing extension portion37and the lower extension portion50are overlaid with each other, the three sewn joint portions40a,40b,40cof the pushing extension portion37and the two sewn joint portions40d,40eof the lower extension portion50are formed in an arrangement where they are shifted with each other. Because of this, the four pushing extension chambers37a,37b,37c,37dof the first bag35and the three upper/lower extension chambers39a,39b,39cof the second bag36are respectively inflated and extend also in an arrangement where they are shifted with each other.

Then, the pushing extension portion37of the first bag35and the lower extension portion50of the second bag36are joined by being sewn together via the connection panel PN (refer toFIG. 8, described later), which becomes a connection member.

As shown inFIG. 8, the connection panel PN serves to guide the extension directions of the first and second bags35,36in a fixed direction when the pushing extension portion37and the lower extension portion50of the first bag35and the second bag36are inflated and extend, and is constituted of a sheet of fabric (non-inflatable fabric body) so that its both side faces are formed in the same configurations as the external shapes of the first bag35and the second bag36when overlaid together. The connection panel PN is provided with four attachment pieces PNa, PNa, PNb, PNb so as to project from upper and lower portions in both sides thereof, respectively, as with the above first and second bags35,36, and is also provided with a recessed portion Q, which is formed in the center of a lower portion thereof. These attachment pieces PNa, PNa, PNb, PNb are attached together with corresponding attachment pieces which are formed on both sides of the first and second bags35,36, respectively.

The upper portion of the connection panel PN is, as shown inFIG. 9, joined with two sewn joint portions40b,40clocated on the both sides of the three sewn joint portions40a,40b,40cindividually forming the four pushing extension chambers37a,37band37c,37dof the first bag35, and is also joined with the sewn joint portion40, by which the second bag36is joined with a sealing material at its both sides, and with the circular sewn joint portion SC forming the circular non-inflated portion C, which is provided in the substantially central portion of the lower extension portion50.

Further, the lower portion of the connection panel PN is, as shown inFIG. 10, joined with the sewn joint portions40,40by which the second bag36is joined at its both sides, and with the circular sewn joint portions SL, SR which individually form the pushing extension chambers37a,37band37c,37dof the first bag35and sew the circular non-inflated portions L, R, respectively.

That is, the connection panel PN is connected with the sewn joint portions SL, SR (connection portions for the first bag) and the sewn joint portions40b,40c(connection portions for the first bag) on the upper side, as one side, of the first bag35(the second bag side, shown on the under side inFIG. 9andFIG. 10) when inflated and extends, while being connected with the sewn joint portion SC (connection portion for the second bag) and the sewn joint portions40,40(connection portions for the second bag) on the lower side, as the other side, of the second bag36(the first bag side, shown on the upper side inFIG. 9andFIG. 10).

As the connection portions for the second bag, there are provided a plurality of pairs of left and right sewn joint portions40, which have different distances from the center line in a vehicle width direction, where the circular non-inflated portion C is provided, the plurality of pairs of sewn joint portions40being sewn along the peripheral portion.

In the next place, a sewing procedure for joining the connection panel PN in between the first bag35and the second bag36by sewing will be described with reference toFIG. 9andFIG. 10.

First, as shown inFIG. 9, the lower side of the connection panel PN is joined by being sewn with the sewn joint portions SL, SR of the two non-inflated portions L, R provided in the pushing extension portion37of the first bag35, and then the upper side of the connection panel PN is joined by being sewn with the sewn joint portion SC of the non-inflated portion C provided in the lower extension portion50of the second bag36.

Next, after both sides of the sewn joint portion SC joined to the upper side of the connection panel PN by being sewn are joined with the sewn joint portions40a,40b,40c, both sides of the connection panel PN are joined with the sewn joint portions40,40, which sew both sides of the second bag36; thereby the connection panel PN is joined by being sewn in between the first bag35and the second bag36.

FIG. 11(a) is a perspective partially cut-away view showing a joint portion between a flow-out passage35tand a flow-in passage36ion one side inFIG. 4by magnifying,FIG. 11(b) is a perspective view showing the exterior of a covering portion covering the outer periphery of the joint portion between the flow-out passage35tand the flow-in passage36ion one side, the covering portion having an attachment member, andFIG. 12is a cross-section view taken from C-C inFIG. 11(a).

As shown inFIG. 12, the flow-out passage35tof the first bag35is inserted inside the flow-in passage36iof the second bag36, and the overlapped portion is joined with the flow-passage connecting member60. This flow-passage connecting member60includes a hollow connection pipe61inserted into the overlapped portion, where the flow-out passage35tand the flow-in passage36iare overlapped, and an outer periphery fastening member62installed at the overlapped portion so as to fasten the flow-in passage36ifrom the outside of its outer periphery.

The hollow connection pipe61is composed of, for example, a relatively hard plastic material, and is formed in a circular tubular (pipe-like) shape having an inner diameter adequate to allow a pressurized fluid to smoothly pass therethrough. The outer periphery fastening member62serves to secure the overlapped portion of the flow-out passage35tand the flow-in passage36ito the hollow connection pipe61by fastening from the outside of the outer periphery thereof with hermetically sealing; a “Ty-Rap”, a clamp band, or the like, for example, is applicable for the purpose.

When the first bag35and the second bag36are thus coupled into one air bag11and installed into the retainer12, they are accommodated therein in a state of being folded. At this time, since the hollow connection pipe61is composed of a hard material, its shape is hardly crushed, i.e., the cross-sectional shape and the state of connection of the overlapped portion of the flow-out passage35tand the flow-in passage36ican be maintained even when the airbag is folded.

Moreover, the outer periphery side of the overlapped portion where the flow-out passage35tof the first bag35is inserted inside the flow-in passage36iof the second bag36, and also the outer periphery side of the outer periphery fastening member62, which secures the overlapped portion to the outer periphery of the hollow connection pipe61, constituting the outer periphery fastening member62, are covered with a pipe band B, serving as a protection member. In addition, on the side of an upper portion of the pipe band B, an attachment piece T is mounted so as to project therefrom, the attachment piece T being provided with two attachment holes H corresponding to attachment threaded-holes in a lower portion of the retainer12. The pipe band B is covered with a tubular body made of, for example, fabric, iron, plastic.

According to an airbag device10of this embodiment, as constituted as described above, the following advantages are obtained.

That is, in an airbag device10of this embodiment, a first bag35including a gas supply port35asupplying gas supplied from an inflator13into the inside and a flow-out passage35tallowing the gas supplied into the inside to flow out into the outside, and a second bag36including a flow-in passage36iallowing the gas flowed out from the flow-out passage35tof the first bag35to flow into the inside are connected by a connection panel PN so that the first bag35and the second bag36becomes a predetermined shape on the whole.

With this, when the airbag is inflated and extends, the flexibility of extension movement of the first bag35and the second bag36is restricted by the connection panel PN, and the extension direction can be guided in a fixed direction. As the result, a pressurized fluid is allowed to pass through smoothly from the first bag35to the second bag36; thereby the extension ability of an entire airbag can be improved.

In addition, this embodiment is particularly configured such that the connection panel PN connects the sewn joint portions SL, SR and the sewn joint portions40b,40c(connection portions for the first bag) connected to the upper side, as one side, of the first bag35when inflated and extends, and the connection portions for the second bag connected at the sewn joint portion SC and the sewn joint portions40,40connected to the lower side, as the other side, of the second bag36.

With this, since the connection panel PN is connected to the one side of the first bag35by the sewn joint portions SL, SR and the sewn joint portions40b,40c, and is also connected to the other side of the second bag36by the sewn joint portion SC and the sewn joint portions40,40when the airbag is inflated and extends, the first and second bags35and36at the time when inflated and extends are allowed to extend in a good balance without unbalanced when inflated and extends.

Moreover, this embodiment is particularly configured such that the sewn joint portion SC and the sewn joint portions40,40of the connection panel PN are a plurality of pairs, which are located different positions in a vehicle width direction with each other, each of the pairs being positioned in left and right sides of the center line in the vehicle width direction.

With this, the second bag36when inflated and extends can extend in a state that a vehicle width direction connected by a plurality of pairs with each other, each of the pairs being positioned in left and right sides of the center line in the vehicle width direction is restricted by the sewn joint portion SC and the sewn joint portions40,40of the connection panel PN.

Moreover, this embodiment is particularly configured such that the connection panel PN is composed of a fabric body. With this, the first bag35and the second bag36can extend as being guided in mutually fixed directions. In addition, when accommodated in the retainer12, the connection panel PN can also be accommodated in a state of being folded together with the first bag35and the second bag36.

Moreover, this embodiment is particularly configured such that the connection panel PN is composed of a non-inflatable fabric body. With this, the first bag35and the second bag36can be guided in fixed directions in a state that the positioning relationship therebetween is mutually restricted, when the airbag is inflated and extends.

Moreover, this embodiment is particularly configured such that since the first bag35includes the pushing extension portion37being inflated and extending by the pressurized fluid supplied from the inflator13, and the second bag36includes the upper extension portion, which is inflated and extends toward the above of the head portion of the occupant, when the pressurized fluid is supplied from the inflator13, the pushing extension portion37of the first bag35is inflated and also (further together with an extension promoting function of extension deriving portions90, described later) the upper extension portion39of the second bag36is inflated and extends toward the above of the head portion of the occupant; thereby the head portion of the occupant can be restrained from moving upward.

Moreover, this embodiment is particularly configured such that the pushing extension portion37of the first bag35is inflated and extends on the side facing the back of the head of the occupant2, and the second bag36is provided with the lower extension portion, which is inflated and extends on the side opposite with respect to the occupant and is disposed to overlay the pushing extension portion37. With this, it becomes possible to change the posture of the back of an occupant's head to lean forward effectively due to the thickness of the two portions of the pushing extension portion and the lower extension portion.

It is a matter of course that each configuration of the embodiment described above does not limit the contents of the present invention, and may be practiced in various other forms not departing from the spirit and scope of the invention. For example, not a sheet of fabric but a plurality of sheets of fabric may be used for the above connection panel PN, or it may be composed of a bag body which is not inflated so much, or may further be composed of a sheet of non-inflatable fabric or a member which is formed just by sticking one upon another; thereby the first and second bags35,36can be guided in fixed directions without being affected by the flexibility of extension movement.