Head protecting airbag device

In a head protecting airbag device, an airbag includes an inflation portion and a connection port portion. The connection port portion includes: an outlet side portion having a communication port to the inflation portion at its lower end; and an inlet side portion for inserting an inflator therein. The inflator includes a body portion having a gas discharge port, and a diffuser having a gas outlet port. The diffuser is connected with the body portion so as to cover the gas discharge port, having its two ends forced into contact with the outer circumference of the body portion. The inflator is connected to a connection port portion with good sealing properties and the gas outlet port faces toward the communication port of the connection port portion and thus toward the inflation portion. This head protecting airbag device simplifies the connection structure between the inflator and the airbag while retaining the quick expansion and inflation of the airbag.

This application claims priority from Japanese patent application of Ogata et al, filed Nov. 22, 2001, No. 2001-358093, the complete disclosure of which is hereby incorporated into the present application by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a head protecting airbag device. The airbag of the head protecting airbag device is folded and housed in the upper peripheral edge of a window in the interior side of a vehicle so that it may be expanded and inflated, when it admits an inflating gas, to cover the interior side of the window.

2. Description of the Related Art

Usually in the head protecting airbag device of this kind, an inflated airbag protects an occupant. Therefore, the head protecting airbag device is desired, when activated, to develop the airbag quickly. The construction of Unexamined Published Japanese Patent Application No. 2000-296753 is known as the head protecting airbag device which is constructed to expand the airbag quickly.

This head protecting airbag device is provided with two connection port portions at the upper edge side near the longitudinal middle of the airbag. These two connection port portions are opposed to each other in the longitudinal direction. The front and rear ends of the inflator are individually inserted into the two connection port portions so that the inflator is connected with the two connection port portions in a straight line.

When this airbag device is activated, the inflating gas is discharged from the two ends of the inflator in the axial direction of the inflator. Then, the inflating gas flows, through the two connection port portions of the airbag, in two directions, i.e., to the front side and to the rear side in the longitudinal direction of the vehicle so as to inflate the airbag.

In the head protecting airbag device of the prior art, however, the inflating gas, as discharged from the two ends of one inflator, is guided into the airbag through the two connection port portions. In other words, the airbag device of the prior art has two connection portions which connect the inflator and the connection port portions of the airbag. Therefore, in the head protecting airbag device of the prior art, the connecting work becomes complicated in the light of sealing properties, which caused a large number of working steps and a high cost.

Especially in the head protecting airbag device of the prior art, the front and rear ends of the inflator are individually inserted into the connection port portions. These connection port portions have to be sealed up by forcing them to contact with the outer circumference of the inflator. However, the inflator and the two connection port portions are connected in a straight line so that the inflating gas discharged in the axial direction of the inflator flows in the axial directions of the individual connection port portions. In other words, the connection port portions are easily pulled out from the end portions of the inflator if a pressure put on the individual connection port portions against the outer circumference of the inflator is low. This makes it necessary to connect the individual connection port portions and the inflator with great connection strength, including sealing properties. As a result, the head protecting airbag device of the prior art needs a large number of working-steps and thus high cost for assembly.

SUMMARY OF THE INVENTION

The present invention is intended to solve the above-specified problems. Specifically, the invention has the objective of providing a head protecting airbag device which simplifies the connection structure between an inflator and an airbag while retaining a quick expansion and inflation of the airbag and which reduces the number of working-steps and the cost of its assembly.

A head protecting airbag device according to the present invention comprises an airbag and an inflator for feeding an inflating gas to the airbag. The airbag is folded and housed at the upper peripheral edge of the window along the longitudinal direction on the interior side of a vehicle and is expanded and inflated downward when it admits an inflating gas to cover the interior side of the window. Moreover, the airbag includes an inflation portion and one cylindrical connection port portion. The inflation portion is inflated when it admits the inflating gas to separate an interior side wall portion and an exterior side wall portion of the airbag, thereby to shield the window. The connection port portion is arranged at generally the middle in the vehicle longitudinal direction of the upper edge of the airbag and is formed to communicate with the inflation portion, protruding upward from the inflation portion. The connection port portion guides the inflating gas from the inflator to the inflation portion. The connection port portion includes an outlet side portion and an inlet side portion. The outlet side portion has a generally vertical axial direction and has a communication port at its lower end for communicating with the inflation portion, to release the inflating gas to the inflation portion. The inlet side portion is arranged above the outlet side portion and is connected to the inflator for admitting the inflating gas from the inflator. Moreover, the inflator includes a body portion and a diffuser. The body portion is formed into a cylinder having a gas discharge port opened on the outer circumference for discharging the inflating gas. The diffuser is formed of a metal into a cylindrical shape to cover the gas discharge port of the body portion, and is attached to the body by pressing the two ends on the outer circumferential surface of the body. Moreover, the diffuser has a gas outlet port opened on its outer circumference for releasing the inflating gas. The inflator is inserted into the inlet side portion of the connection port portion of the airbag and is connected to the connection port portion with good sealing. Thus, the inflator is arranged to have its gas outlet port opposed to the communication port of the connection port portion and to face toward the inflation portion.

Here, close to the longitudinal middle of the airbag where the connection port portion is arranged is not limited to the longitudinal center of the airbag but means the position at which a part of the inflation portion is arranged on both the front side and the rear side of the connection port portion.

In the head protecting airbag device according to the invention, when activated, the inflating gas discharged from the gas discharge port of the body portion of the inflator goes through the clearance between the outer circumference of the body portion and the inner circumference of the diffuser and flows into the single connection port portion of the airbag. Moreover, the inflating gas is released from the communication port of the connection port portion into the inflation portion of the airbag. Then, the airbag inflates at its inflation portion by admitting the inflating gas so that it is expanded downward from the upper edge of the window.

Specifically, in the head protecting airbag device of the present invention, the inflating gas from the inflator is fed to the inner side of the airbag through the single connection port portion. Unlike the prior art in which the two ends of the inflator are connected to the two connection port portion, therefore, the airbag device of the invention has its connection with the inflator through a single connection port portion. Therefore, it is easy to connect the inflator and the connection port portion.

When the inflating gas flows into the inflation portion of the airbag, on the other hand, the gas outlet port of the inflator is opposed to the communication port at the lower end of the connection port portion and face toward the inflation portion. The gas outlet port is opened on the outer circumference of the diffuser and is axially directed generally perpendicular to the axial direction of the inflator. Specifically, the communication port in the outlet side portion of the connection port portion is axially directed generally perpendicular to the axial direction of the inflator, as the gas outlet port. As a result, the inlet side portion of the connection port portion into which the inflator is inserted is roughly perpendicular to the axial direction of the communication port, that is, is bent generally perpendicular to the outlet side portion of the connection port portion.

Therefore, the inflating gas from the inflator is injected generally perpendicular to the axial direction of the body portion or the diffuser of the inflator so that it flows into the outlet side portion and further into the inflation portion of the airbag. At this time, even if the outlet side portion is given downward force by the injection force of the inflating gas, the inner circumference of the inlet side portion, especially, the portion away from the communication port, is held by the portion of the outer circumference of the inflator away from the communication port, so that the outlet side portion is prevented from separating from the inflator. As a result, even if the connection structure between the inflator and the inlet side portion of the connection port portion is simplified to weaken the connection strength, the inflator itself holds the connection port portion with a part of its outer circumference, when the airbag device acts. Specifically, even if the connection structure between the inflator and the inlet side portion of the connection port portion is simplified, and thereby weakening the connection strength, it is possible to prevent the connection port portion from separating from the inflator.

On the other hand, the assembly of the diffuser with the body portion of the inflator is made by the simple structure in which the two ends of the diffuser are pressed on the body portion. However, the inflating gas is injected generally perpendicular to the axis of the body portion or the diffuser from the gas outlet port of the diffuser. Thus, even if the assembling force of the two ends of the diffuser to the body portion is weak, therefore, the diffuser is prevented from separating from the body portion. As a result, the inflator itself can be assembled by connecting the diffuser and the body portion simply.

The inflating gas that flows into the inflation portion of the airbag naturally flows toward the longitudinal middle position of the inflation portion through the connection port portion. Therefore, the inflating gas promptly reaches the two longitudinal ends of the inflation portion so that the airbag device can retain quick expansion and inflation of the inflation portion of the airbag.

In the head protecting airbag device according to the invention, therefore, the quick expansion and inflation of the airbag is retained while simplifying the connection structure between the inflator and the airbag. In the airbag device of the invention, moreover, the inflator itself can be simply assembled and thereby the number of working-steps and the cost of its assembly are reduced.

Moreover, the diffuser of the inflator are so assembled on the body portion as to force the two ends of the diffuser to contact with the body portion. In short, the diffuser overlaps the body portion so that the inflator can be compactly constructed without elongating its axial length.

Moreover, it is desired that two gas outlet ports are arranged in the diffuser for releasing the inflating gas in two directions obliquely, i.e., forward and downward, and rearward and downward. In this construction, the inflating gas flows in the two directions, i.e., forward and downward, and rearward and downward, into the inflation portion from the two gas outlet ports of the diffuser through the communication port of the outlet side portion. Therefore, the inflating gas smoothly reaches the two longitudinal ends of the inflation portion so that the airbag can retain a quicker expansion and inflation.

Moreover, it is desired that the gas outlet port is arranged at the side of the center or the end portion of the inflator on the side apart from the gas discharge port in case the gas discharge port is arranged close to the end portion of the body portion. This construction enables the use of an inflator in which the side of the gas discharge port of the body portion cannot be inserted into the inlet side portion of the connection port portion, such as an inflator of a stored gas type which is charged with a cold gas. In a stored gas type inflator, specifically, the actvating lead wires are arranged at the end on the side where the gas discharge port of the body portion is arranged. An inflator of this kind is inserted from the end portion thereof on which no lead wires are arranged into the inlet side portion of the connection port portion so that the end to which the lead wires are connected may be exposed from the opening of the inlet side portion of the connection port portion. With the aforementioned construction, the gas outlet port of the diffuser is smoothly arranged to face the communication port.

Moreover, it is desired that the inlet side portion of the connection port portion of the airbag is arranged along the longitudinal direction of the vehicle. With this construction, the inflator is inserted into the inlet side portion while the inlet side portion of the connection port portion of the airbag is arranged in the longitudinal direction of the vehicle, i.e., in parallel to the inflation portion of the airbag. Therefore, the inflator is easily arranged in the narrow space on the upper edge side of the windows of the vehicle.

Still moreover, the connection port portion of the airbag may have the inlet side portion bent from the outlet side portion, to have an L-shape.

Moreover, the inlet side portion is opened on both front and rear ends and is formed to protrude to the front and rear sides from the upper side of the outlet side portion. It is desired that the inlet side portion is sealed on the inflator at two portions of the front and rear sides on either side of the outlet side portion, by being pressed against the outer circumference of the inflator along the circumferential direction. With this construction, the outlet side portion constitutes the vertical rod portion of the T-shape whereas the inlet side portion constitutes the horizontal rod portion of the T-shape, so that the connection port portion forms a T-shape. Moreover, the two sealed portions of the inlet side portion are formed at the front and rear ends on either side of the outlet side portion, so that the inflator may be inserted from either side of the ends of the inlet side portion. As a result, the flexibility of connecting the inflator and the airbag is increased. Moreover, the sealed portions of the inlet side portion on the inflator are individually formed by being pressed against the outer circumference of the inflator along the circumferential direction, although they are formed at two positions of front and rear sides on either side of the outlet side portion. Specifically, the sealed portions retain the sealing pressure in the circumferential direction or in the direction generally perpendicular to the injection direction of the inflating gas which is injected from the gas outlet port of the diffuser. Therefore, the sealed portions of the inlet side portion retain the sufficient sealing properties even if the sealing pressure is not high. As a result, the sealing structure of the inlet side portion and the inflator is simplified, maintaining good workability in connecting the inflator and the connection port portion.

Moreover, it is desired that the inflator is attached to the vehicular body at two positions of the front and rear sides on either side of the outlet side portion. With this construction, the inflator itself is stably mounted on the vehicular body. When the inflator is activated, moreover, pressure is applied to the outlet side portion in the direction away from the inflator by the injection force of the inflating gas. However, the inflator is inserted into the inlet side portion which is protruded to the front and rear above the outlet side portion. Therefore, the inflator itself restricts the movement of the outlet side portion at its two ends of the inlet side portion on either side of the outlet side portion, thereby to support the connection port portion stably.

Moreover, it is desired that the sealed portion of the diffuser has a clearance from the outer circumference of the body portion, in case the inlet side portion is sealed on the outer circumference of the inflator at least at one position by being pressed against the circumference of the diffuser along the circumferential direction. With this construction, even if the sealing pressure for sealing the inlet side portion on the diffuser is raised to a predetermined or higher level, the diffuser can be warped to narrow the clearance from the body portion. Therefore, the sealing pressure on the inlet side portion need not be strictly set, which facilitates the connecting work of the connection port portion and the diffuser.

Moreover, the gas outlet port of the diffuser may be arranged to project into the outlet side portion closer to the inflation portion. With this construction, the inflating gas flows smoothly into the inflation portion.

Moreover, it is desired that the inflation portion of the airbag includes a feed passage portion and a shielding body portion. The feed passage portion is arranged on the upper edge side of the airbag to communicate with the connection port portion, and extends in the longitudinal direction of the vehicle. The shielding body portion is arranged below the feed passage portion, and substantially covers the interior side of the window when inflated. Moreover, the shielding body portion includes a plurality of vertical cells lined up in the longitudinal direction of the vehicle so as to inflate into vertical rod shapes with the inflating gas introduced through the feed passage portion into the inflation portion. With this construction, the inflating gas flowing into the airbag flows into the feed passage portion which is arranged in the longitudinal direction of the vehicle on the upper edge of the airbag. Therefore, the vertical cells on the front and rear ends of the inflation portion are smoothly inflated so that the airbag attains quick expansion and inflation.

In this case, the airbag may also be constructed in the following manner. The inflation portion of the airbag includes a communication passage portion arranged along the longitudinal direction of the vehicle on the lower edge side of the airbag for providing communications between the individual vertical cells and the lower end. One of the vertical cells is arranged right below the connection port portion in the airbag with its opening narrowed on the side of the feed passage portion. The front and rear adjacent vertical cells thereof are individually closed at their upper ends.

With this construction, the vertical cell just below the connection port portion has a narrowed opening on the side of the feed passage portion, and the two vertical cells on the two sides thereof are closed at their upper ends. Therefore, the inflating gas flowing from the outlet side portion of the connection port portion into the inflation portion is prevented from flowing in a large quantity into the vertical cells in the vicinity of the connection port portion. In other words, the inflating gas flowing from the outlet side portion into the inflation portion is smoothly guided to the front and rear sides of the feed passage portion. Further, a part of the inflating gas smoothly flows from the vertical cell just below the connection port portion, through a communication passage portion, into the vertical cells at the front and rear ends of the inflation portion. Therefore, the quick expansion and inflation of the airbag are more promoted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described below by way of embodiments shown in the drawings. In addition, the invention is not limited to the embodiments. All modifications within the requirements of the claims and equivalents with respect to the requirements should be included in the scope of the claims.

As shown inFIG. 1, a head protecting airbag device M1according to one embodiment of the invention includes an airbag11. The airbag11folded is housed in the lower edge of a front pillar portion FP, the lower edge of a roof side rail portion RR and above a rear pillar portion RP in the upper peripheral edge of windows W (W1, W2and W3) on the interior side of a vehicle V. Here in the vehicle V of the embodiment, two first and second intermediate pillar portions P1and P2are arranged between the front pillar FP and the rear pillar portion RP. The airbag11is housed to extend over those pillar portions P1and P2.

The airbag device M1is constructed to include the airbag11, an inflator36, mounting brackets33and57, clamps55and an airbag cover8.

The airbag cover8is built, as shown inFIG. 1, of the lower edges4aand5aof a front pillar garnish4and a roof head lining5. The front pillar garnish4is arranged in the front pillar portion FP, and the roof head lining5is arranged in the roof side rail portion RR. The airbag cover8is arranged to cover the interior side of the airbag11folded and housed. Moreover, the cover8is constructed to open into the interior of the vehicle by the push of the airbag11so that the airbag11being expanded and inflated may protrude into the vehicular compartment.

The airbag11is manufactured by hollow-weaving of polyamide yarns or the like. The housed airbag11is expanded and inflated downward from the upper edge side of the window W by admitting an inflating gas G from the inflator36, as shown inFIGS. 1to3. Then, the airbag11having completed its inflation covers the interior side of the windows W1, W2and W3and the pillar garnishes7and6of the first and second intermediate pillar portions P1and P2and the rear pillar portion RP. On the other hand, referring now toFIG. 2, the airbag11comprises a gas inlet portion13admitting the inflating gas G therein, and a blocking portion25which allows no inflating gas G to pass therein.

The gas inlet portion13is provided with an inflation portion14and a connection port portion19. The inflation portion14is inflated, when the inflating gas G flows in, to separate an interior side wall portion14aand an exterior side wall portion14b. The inflation portion14which has completed its inflation shields the windows W and covers the interior sides of the pillar portions P1and P2. The connection port portion19guides the inflating gas G from the inflator36into the inflation portion14. The connection port portion19is formed in a T-shaped cylinder, as viewed from the interior compartment, and is arranged at generally the middle in the vehicular longitudinal direction at the upper edge11aof the airbag11. The connection port portion19communicates with the inflation portion14and is protruded upward from the inflation portion14.

The inflation portion14includes a feed passage portion15, a shielding body portion16and a communication passage portion17. The feed passage portion15is arranged at the side of the upper edge11aof the airbag11and in the longitudinal direction of the vehicle V. The shielding body portion16is arranged below the feed passage portion15and substantially covers the interior sides of the windows W and the pillar portions P1and P2. The communication passage portion17is arranged on the side of the lower edge11bof the airbag11and in the longitudinal direction of the vehicle. In the shielding body portion16, there are longitudinally juxtaposed a plurality of vertical cells16awhich bulge in vertical rod shapes. The feed passage portion15is formed to feed the inflating gas G smoothly to the two front and rear ends of the inflation portion14. The individual vertical cells16acommunicate at their upper end sides with the feed passage portion15, excepting the vertical cells16aaand16acadjoining the vertical cell16abjust below the connection port portion19. Moreover, the individual vertical cells16acommunicate at their lower ends with the communication passage portion17. This communication passage portion17feeds the inflating gas G having reached the lower end of the vertical cell16ab, smoothly to the two front and rear sides of the inflation portion14.

The connection port portion19includes an inlet side portion20and an outlet side portion21. The inlet side portion20is so connected to the inflator36as to admit the inflating gas G from the inflator36. The outlet side portion21releases the inflating gas G to the inflation portion14. The outlet side portion21is formed into a generally cylindrical shape having an axis generally in the vertical direction. The outlet side portion21is provided at its lower end with a communication port21a, which communicates with the feed passage portion15of the inflation portion14. The inlet side portion20is arranged above the outlet side portion21. The inlet side portion20is formed into a generally cylindrical shape having an axis in the longitudinal direction of the vehicle, and is provided with openings20band20din its two front and rear end portions20aand20c. The outlet side portion21communicates at its upper end with the longitudinal middle of the inlet side portion20.

The blocking portion25is constructed by joining the interior side wall portion14aand the exterior side wall portion14b. In the case of the embodiment, the blocking portion25is constructed of mounting portions26, a peripheral edge portion27, thickness regulating portions28, connection portions29and board portions30.

The peripheral edge portion27is arranged adjacent to the gas inlet portion13. The peripheral edge portions27are densely woven to cause no gas leakage. The mounting portions26are provided in plurality (e.g., nine in the embodiment) and are individually protruded upward from the peripheral edge portion27at the upper edge11aand from triangular board portions30aof the airbag11. To each mounting portion26, there is fixed a mounting bracket33for attaching the airbag11to the body1of the vehicle V. Moreover, each mounting portion26is provided with a mounting hole26athrough which to insert a mounting bolt34. The individual mounting portions26are fixed together with the mounting brackets33on an inner panel2of sheet metal on the side of the body1by using the mounting bolts34.

The board portions30are arranged to maintain the entire shape of the airbag11and to reduce the volume of the gas inlet portion13. The board portions30helps shorten the time period for the airbag11to start and complete its inflation. Moreover, the board portions30are composed of the triangular board30aarranged on the front end side of the airbag11, and a triangular board30barranged on the rear end side of the airbag11. The thickness regulating portions28are so vertically arranged as to divide the individual vertical cells16a. Here, the thickness regulating portion28A on the front of the vertical cell16aais made to have a larger width than that of the remaining thickness regulating portions28.

The connection portions29close off the upper side of the vertical cells16aaand16acby connecting the thickness regulating portions28and28across the individual vertical cells16aaand16ac.

Moreover, the thickness regulating portions28and28located just below the connection port portion19and on the upper end side of the vertical cell16aband opposed to each other, are provided with projections28afor narrowing the opening of the vertical cell16ab. These projections28aprevent the inflating gas G flowing from the outlet side portion21of the connection port portion19to the inflation portion14, from flowing in a large amount into the vertical cell16ab. Therefore, the inflating gas G flowing from the outlet side portion21into the inflation portion14is easily guided to the front and rear of the feed passage portion15by those projections28a.

As shown inFIGS. 1,3and4, the inflator36is constructed to include a body portion37and a diffuser45. The body portion37is formed into a cylinder and has gas discharge ports42opened on its outer circumference for discharging the inflating gas G. The diffuser45is formed of a metal into a generally cylindrical shape for covering the gas discharges ports42of the body portion37. The diffuser45is connected to the body portion37by forcing a root end of the diffuser onto a head portion of the body portion37.

The body portion37is of the stored gas type, which is charged with a cold gas. The body portion37is constructed of a generally column-shaped base portion38arranged on the side of a rear end37b, and a generally column-shaped head portion39having a slightly smaller diameter than the base portion38and arranged at the front end (or leading end)37a. The gas discharge ports42are arranged on the outer circumference closer to the leading end39aof the head portion39. With the leading end face of the head portion39, there is connected a connector52for inputting an activation signal from the activation circuit of the airbag device M1. Here, reference numeral53inFIG. 3designates a lead wire. On the side of a root portion39bof the head portion39, on the other hand, there is arranged throughout the circumference a groove41for mounting the diffuser45. Throughout the circumference of the leading end of the head portion39, moreover, there is formed an inward step40for mounting the diffuser45.

The diffuser45is formed of a sheet metal into a generally cylindrical shape. The diffuser45is provided, on the side of its leading end (or front end)45a, with a flange portion46, which is protruded in the inner circumferential direction. The diffuser45is provided, on the side of its root portion (or rear end)45b, with a caulking portion (or plastically deformed portion)47to be fitted in the groove41of the body portion37. In front of the caulking portion47, there is formed a bottomed cylindrical bulge48, which is protruded downward. The bulge48is formed into a conical shape having two gas outlet ports49and50opened in a circular shape. These gas outlet ports49and50release the inflating gas individually downward generally perpendicularly to the axial direction of the body portion37of the inflator36and the diffuser45. More specifically, the gas outlet port49releases the inflating gas G obliquely, forward and downward. When the airbag device is mounted on the vehicle, moreover, the inflating gas G, as released from the gas outlet port49, is guided via the communication port21aof the outlet side portion21of the connection port portion19to the front side of the feed passage portion15in the inflation portion14of the airbag11. Moreover, the gas outlet port50releases the inflating gas G obliquely, rearward and downward. When the airbag device is mounted on the vehicle, moreover, the inflating gas G released from the gas outlet port50is guided through the communication port21aof the outlet side portion21of the connection port portion19to the rear side of the feed passage portion15in the inflation portion14of the airbag11.

The diffuser45has an O-ring44arranged on the inner side face of the flange portion46. When the diffuser45is assembled with the body portion37, it is mounted from its root portion45bon the head portion39of the body portion37, and the flange portion46is brought in contact through the O-ring44to the step40. If the caulking portion47is fitted in the groove41, the front and rear ends45aand45bare assembled with good sealing with the head portion39of the body portion37. As a result, the diffuser45is assembled with the body portion37, so that the inflator36is assembled. Here, numeral43inFIG. 3designates a ring spacer of a synthetic resin, which is arranged on the outer circumference of the groove41so as to protect the groove41from any damage.

When the inflator36assembled is connected to the connection port portion19, the diffuser45is inserted into the inlet side portion20in the connection port portion19of the airbag11with the gas outlet ports49and50being directed downward. Then, the front and rear end portions20aand20cof the inlet side portion20are held by the clamps55and pressed onto the outer circumferences of the front and rear ends45aand45bof the diffuser45. Thus, the inflator36is connected to the connection port portion19. At this connecting time, the gas outlet ports49and50of the diffuser45face opposite the communication port21afrom above, and are arranged to face toward the feed passage portion15of the inflation portion14.

The clamps55are formed of a sheet metal into an annular shape. And, these clamps55are plastically deformed partially into a smaller internal diameter thereby to force the front and rear end portions20aand20cof the inlet side portion20in the connection port portion19to contact with the entire outer circumference of the end portions45aand45bof the diffuser45.

The mounting bracket57has a holding portion57aand a mounting portion57b. The holding portion57asheathes and clamps the base portion38of the body portion37of the inflator36. The mounting portion57bis protruded from the holding portion57a. The mounting portion57bis provided with mounting holes57cand57cfor inserting mounting bolts58therethrough. The individual mounting bolts58are fastened on the inner panel2on the side of the body1of the interior side of the roof side rail portion RR. The mounting bracket57is mounted and fixed on the inner panel2on the side of the body1of the roof side rail portion RR by means of the mounting bolts58while holding the inflator body portion37with the holding portion57a.

Here will be described how to mount the airbag device M1on the vehicle V. First of all, the airbag11is so folded into a bellows shape from its flat and expanded state sequentially with folds C of crests and valleys as to bring the side of the lower edge11bof the airbag11toward the side of the upper edge11a, as indicated by double-dotted lines in FIG.2. The airbag11is wrapped, after folded up, at predetermined portions with not-shown unfolding preventing breakable tape. Moreover, the mounting brackets33are attached to the individual mounting portions25. Moreover, the clamps55are made in advance to sheathe the two end portions20aand20bof the inlet side portion20in the connection port portion19.

Here, the inflator36is assembled in advance by mounting the diffuser45on the body portion37.

Thereafter, as described hereinbefore, the diffuser45is inserted, with the gas outlet ports49and50facing downward, from the side of the rear end portion20cinto the inlet side portion20in the connection port portion19of the airbag11. Moreover, the clamps55and55are fastened to force the front and rear end portions20aand20cof the inlet side portion20to contact with the outer circumferences of the front and rear ends45aand45bof the diffuser45. As a result, the inflator36is connected to the connection port portion19thereby to form the airbag assembly.

At this time, the gas outlet ports49and50of the diffuser45are opposed to the communication port21aof the connection port portion19and directed toward the side of the feed passage portion15of the inflation portion14.

Here, the mounting bracket57may be attached to the inflator body portion37either in advance or after the diffuser45was assembled.

After this, the individual mounting brackets33and57are arranged at predetermined positions of the inner panel2, and the airbag assembly is attached to the body1by means of the bolts34and58. Next, the connector52having the lead wires53extended from a predetermined inflator activating control device is joined to the leading end face of the inflator body portion37. Then, the pillar garnishes4,6and7and the roof head lining5are attached to the body1so that the airbag device M1can be mounted on the vehicle V.

If the inflator36is activated after the airbag device M1is mounted on the vehicle V, the inflating gas G is discharged from the gas discharge ports42of the body portion37of the inflator36. The inflating gas G is released through the clearance between the outer circumference of the body portion37and the inner circumference of the diffuser45and flows from the gas outlet ports49and50of the diffuser45into the single connection port portion19of the airbag11, as indicated by double-dotted lines inFIGS. 2 and 3. Moreover, the inflating gas G flows from the communication port21aof the connection port portion19into the inflation portion14of the airbag11. Then, the airbag11is expanded downward from the upper edge side of the windows W by inflating the inflation portion14.

In the head protecting airbag device M1of the first embodiment, the inflating gas G from the inflator36is fed to the inside of the airbag11through the single connection port portion19. In the airbag device M1, specifically, the inflator is connected to the single connection port portion19, not like the prior art in which the two ends of the inflator are connected to two connecting ports. In the airbag device M1of the first embodiment, therefore, it is easy to connect the inflator36and the connection port portion19.

In the airbag device M1of the first embodiment, on the other hand, the gas outlet ports49and50of the inflator36are opposed to the communication port21aat the lower end of the connection port portion19and arranged toward the side of the feed passage portion15of the inflation portion14. The gas outlet ports49and50are opened on the outer circumference of the diffuser45and are axially directed generally perpendicular to the axial direction of the body portion37of the inflator36and the diffuser45of the inflator36. Therefore, the communication port21ain the outlet side portion21of the connection port portion19is axially directed like the gas outlet ports49and50generally perpendicular to the axial direction of the inflator36. In short, the inlet side portion20of the connection port portion19having the inflator36inserted thereinto is arranged in the vehicle V generally perpendicular to the axial direction of the communication port21a, that is, bent generally perpendicular to the outlet side portion21.

With this construction, the inflating gas G from the inflator36is injected downward or in the direction generally perpendicular to the axial direction of the body portion37or the diffuser45of the inflator36so that it flows into the outlet side portion21and further into the inflation portion14of the airbag11. Therefore, the outlet side portion21is held firmly by the inflator36even if downward pressure is applied to try to separate the outlet side portion21from the inflator36by the injection force of the inflating gas G. Specifically, the inner circumference of the inlet side portion20, especially, the upper side inner circumference20eon the side apart from the communication port21ais held firmly by the upper side outer circumference45cof the outer circumference of the diffuser45of the inflator36positioned opposite from the communication port21a, so that the outlet side portion21is prevented from separating from the inflator36. As a result, even if the connection structure between the inflator36and the inlet side portion20of the connection port portion19is simplified to weaken the clamping force of the clamps55and55, i.e., the connection strength, the inflator36itself holds the connection port portion19firmly with the portion45cof its outer circumference, when the airbag device M1acts, thereby to prevent the connection port portion19from separating from the inflator36.

In this airbag device M1, on the other hand, the assembly of the diffuser45with the body portion37of the inflator36is made by the simple structure, in which the two ends45aand45bof the diffuser45are pressed against the body portion37. However, the inflating gas G is injected downward generally perpendicular to the axis of the body portion37or the diffuser45from the gas outlet ports49and50of the diffuser45. Even if the assembling force of the two ends45aand45bof the diffuser45to the body portion37is weak, therefore, the diffuser45is prevented from separating from the body portion37. As a result, the inflator36itself is assembled by simply connecting the diffuser45and the body portion37.

Of course, the inflating gas G flowing into the inflation portion14of the airbag11flows toward the longitudinal middle of the inflation portion14through the connection port portion19. Therefore, the inflating gas G promptly reaches the two longitudinal ends of the inflation portion14so that the airbag device M1attains quick expansion and inflation of the individual vertical cells16ain the inflation portion14of the airbag11.

In the head protecting airbag device M1of the first embodiment, therefore, the quick expansion and inflation of the airbag11is retained while simplifying the connection structure between the inflator36and the airbag11and facilitating the assembly of the inflator36itself. Therefore, the airbag device M1can reduce the number of working-steps and the cost of assembly.

Moreover, the diffuser45and the inflator36are so assembled on the body portion37as to force the root end of the diffuser onto a head portion of the body portion37. In short, the diffuser45and the body portion37overlap each other. In the airbag device M1, therefore, the inflator36is compactly constructed without any axial elongation of the inflator36.

In the first embodiment, moreover, the inflating gas G flows in the two oblique directions, i.e., forward and downward, and rearward and downward, into the feed passage portion15of the inflation portion14from the two gas inlet ports49and50of the diffuser45through the communication port21aof the outlet side portion21. Therefore, the inflating gas G smoothly reaches the two longitudinal ends of the inflation portion14so that the airbag11attains an even quicker expansion and inflation.

Especially in the case of the first embodiment, the inflating gas G flows into the feed passage portion15which is arranged in the longitudinal direction of the vehicle V on the side of the upper edge11aof the airbag11. Therefore, the vertical cells16on the front and rear ends of the inflation portion14can be easily inflated so that the airbag11achieves quick expansion and inflation.

In the first embodiment, moreover, inflation portion14of the airbag11is so provided with the communication passage portion17as to extend in the longitudinal direction of the vehicle V on the side of the lower edge11bof the airbag11. Therefore, the inflating gas G easily flows from the vertical cell16abthrough the communication passage portion17smoothly into the vertical cells16aat the front and rear ends of the inflation portion14thereby to promote the quicker expansion and inflation of the airbag11.

In the first embodiment, on the other hand, the inlet side portion20of the connection port portion19of the airbag11is arranged along the longitudinal direction of the vehicle V. In this construction, the inflator36is inserted into the inlet side portion20. In the airbag device M1, therefore, the inflator36can be arranged in the longitudinal direction of the vehicle V in parallel with the inflation portion14of the airbag11. As a result, in the airbag device M1, the inflator36can be easily arranged in the thin roof side rail portion RR on the upper edge side of the windows W of the vehicle V.

In the first embodiment, moreover, the inlet side portion20of the airbag11is opened at its front and rear ends20aand20cand is protruded from the upper portion of the outlet side portion21toward the both front and rear directions. Moreover, the inlet side portion20is sealed against the inflator36at two positions of the front and rear ends20aand20con either side of the outlet side portion21by the pressure on the outer circumference of the diffuser45. In other words, the airbag11forms the connection port portion19into a T-shape having the outlet side portion21as its vertical rod and the inlet side portion20as the horizontal rod. Moreover, the two sealed portions of the inlet side portion20are formed at the front and rear ends20aand20con either side of the outlet side portion21. In the first embodiment, therefore, the inflator36can be inserted from either the front or rear end20aand20cof the inlet side portion20so that the flexibility in connecting the inflator36and the airbag11is increased.

The embodiment is exemplified by the case in which the flange portion46of the diffuser45is inserted from the side of the rear end20cof the inlet side portion20when the inflator36and the airbag11are connected. In case the lead wires53are connected in advance with the inflator36, however, the inflator36may be inserted into the inlet side portion20by inserting the base portion38of the body portion37from the side of the front end20aof the inlet side portion20.

Here in the construction thus far described, the two sealed portions of the inlet side portion20on the inflator36are formed at the front and rear ends20aand20con either side of the outlet side portion21. However, those two sealed portions are individually formed by being pressed on the circumferential direction on the outer circumference of the diffuser45. Specifically, in the sealed portions, sealing pressure is secured in the circumferential direction of the diffuser45generally perpendicular to the injection direction of the inflating gas G to be injected downward from the gas outlet ports49and50. Therefore, those sealed portions retains sufficient sealing properties even if the pressure is not high. In the first embodiment, therefore, the individual sealed portions are enabled to retain the sufficient sealing properties even by the simple construction using the clamps55and55which are fixed by plastic deformation. In the first embodiment, therefore, the sealing structure is simplified to improve the connecting work of the inflator36and the connection port portion19.

Here will be described a head protecting airbag device M2of a second embodiment, as shown inFIGS. 5 and 6. In this second embodiment, an inflator66is partially different from that of the first embodiment, and an airbag11A is different from the airbag11of the first embodiment. In this airbag device M2, moreover, there are used two mounting brackets75and76for mounting the inflator66on the vehicle V.

Here, the individual mounting brackets75and76include radially reducible cylindrical holding portions75aand76a, and mounting portions75band76bhaving mounting holes75cand76cfor inserting the mounting bolts58thereinto. And, the mounting bracket75is mounted and fixed on the inner panel2by the bolt58while holding the outer circumference of the root portion67bof a body portion67with the holding portion75a. The mounting bracket76is mounted and fixed on the inner panel2by the bolt58while holding the outer circumference of a leading end70aof a diffuser70, which is sheathed by the inlet side portion20of the connection port portion19, with the holding portion76a.

And, the airbag11A is constructed like the airbag11excepting that the outlet side portion of the connection port portion19in the airbag11A is slightly vertically longer than that of the airbag11. Therefore, the description of the portions of the airbag11A similar to those of the airbag11will be omitted, including the inlet side portion20of the connection port portion19to insert the inflator66thereinto, designating them the same reference numerals as those of the airbag11.

Moreover, the inflator66of the second embodiment includes the body portion67and the diffuser70, as shown inFIGS. 5 and 6. The body portion67is formed into a cylinder type having gas discharge ports68opened on its outer circumference for discharging the inflating gas G. The diffuser70is formed of a metal into a generally cylindrical shape and is assembled with the body portion67while covering the gas discharge ports68, by being pressed on the outer circumference of the body portion67at the two ends.

The generally cylindrical body portion67is of a stored gas type, which is charged with a cold gas. The body portion67has a plurality of gas discharge ports68in the outer circumference of the side of a front end67a, and the connector52having the lead wires53connected thereto is jointed to the end face of the front end67a. The diffuser70is provided on the side of its leading end (or front end)70awith a flange portion71protruded in the inner circumferential direction, and on the side of its root portion (or rear end)70bwith curved portion72, which is curved toward the inner circumference to come into contact with the entire outer circumference of the body portion67. In the lower portion toward the lower end70bof the diffuser70, moreover, there is formed one gas outlet port73, which is opened in a circular shape and is perpendicular to the axial direction of the body portion67of the inflator66and the diffuser70. This gas outlet port73releases the inflating gas G downward. When mounted on the vehicle, the inflating gas G released from the gas outlet port73is guided into the feed passage portion15in the inflation portion14of the airbag11A through the communication port21aof the outlet side portion21of the connection port portion19.

The diffuser70is assembled with the body portion67by arranging the O-ring44at the inner side face of the flange portion71and by sheathing the body portion67in the curved portion72at the root portion70bfrom the front end67a. Then, the side of the flange portion71is forced to contact with the outer circumference of the leading end67awhile interposing the O-ring44, and the curved portion72is pressed against the outer circumference of the root portion67b. Thus, the front and rear ends70aand70bare connected to the outer circumference of the body portion67with good sealing properties. As a result, the diffuser70is assembled with the body portion67and so the inflator66is assembled.

The inflator66thus assembled has its gas outlet port73directed downward, and its rear end66bis inserted from the side of the front end portion20aso that the diffuser70is inserted into the inlet side portion20of the connection port portion19of the airbag11A. Then, the front and rear end portions20aand20cof the inlet side portion20are held by the clamps55to contact forcibly with the front and rear ends66aand66bof the inflator66, i.e., with the outer circumference near the front end70aof the diffuser70and near the root portion67bof the body portion67. Thus, the inflator66is connected to the connection port portion19.

At this connecting time, the airbag11A is folded as in the first embodiment, and has the mounting brackets33attached thereto. Moreover, the gas outlet port73of the diffuser70faces opposite the communication port21aof the connection port portion19above the communication port21aand thus is directed toward the feed passage portion15of the inflation portion14.

After the inflator66is connected to the connection port portion19, the airbag11A and the inflator66are mounted and fixed on the vehicle V by using the mounting bolts34and58, as in the first embodiment. Thus, the airbag device M2is mounted on the vehicle V.

In this second embodiment, too, the inflating gas G is discharged from the gas discharge ports68of the body portion67of the inflator66, if the inflator66is activated after mounted on the vehicle V. The inflating gas G discharged is released from the gas outlet port73of the diffuser70through the clearance between the outer circumference of the body portion67and the inner circumference of the diffuser70into the single connection port portion19of the airbag11A, as indicated by two-dotted lines inFIGS. 5 and 6. Moreover, the inflating gas G flows from the communication port21aof the connection port portion19into the inflation portion14of the airbag11A. Then, the airbag11A admits the inflating gas G to inflate the inflation portion14so that it is expanded downward from the upper edge sides of the windows.

In this head protecting airbag device M2of the second embodiment, too, the inflating gas G from the inflator66is fed through the single connection port portion19into the airbag11A. Specifically, in this airbag device M2, too, the inflator66is connected to the single connection port portion19, instead of the construction of the prior art in which the both ends of the inflator are connected to two connection ports, so that the inflator66and the connection port portion19are easily connected to each other.

Moreover, the inflating gas G from the inflator66is injected downward, or in the direction perpendicular to the axial direction of the body portion67and the diffuser70of the inflator66into the outlet side portion21and further into the inflation portion14of the airbag11A. Therefore, the injection force of the inflating gas G tries to move the outlet side portion21downward away from the inflator66. However, the inner circumference of the inlet side portion20, especially, the upper side inner circumference20eon the side apart from the communication port21a, is held firmly by the upper side outer circumference70cof the diffuser70of the inflator66opposite from the communication port21a. Therefore, the outlet side portion21is prevented from separaing from the inflator66. As a result, the inflator66itself holds firmly the connection port portion19by the portion70cof its outer circumference when the airbag device M2acts, even if the connection structure between the inflator66and the inlet side portion20of the connection port portion19is simplified to weaken the fastening force of the clamps55and55and weaken the connection strength. Therefore, this airbag device M2also prevents the connection port portion19from separating from the inflator66.

In this airbag device M2, on the other hand, the assembly of the diffuser70with the body portion67in the inflator66is made by a simple structure in which the two ends70aand70bof the diffuser70are pressed against the outer circumference of the body portion67. However, the inflating gas G is injected downward, or in the direction generally perpendicular to the axis of the body portion67or the diffuser70from the gas outlet port73of the diffuser70. Even if the assembling force of the two ends70aand70bof the diffuser70to the body portion67is weak, therefore, the diffuser70is prevented from separating from the body portion67. As a result, in this airbag device M2, too, assembly of the diffuser70and the body portion67is easily done to form the inflator66.

The inflating gas G flowing into the inflation portion14of the airbag11A naturally flows toward the longitudinal middle of the inflation portion14through the connection port portion19. Therefore, the inflating gas G promptly reaches the two longitudinal ends of the inflation portion14, so that the airbag11A quickly expands and inflates the individual vertical cells16ain the inflation portion14.

In the head protecting airbag device M2of the second embodiment, therefore, the quick expansion and inflation of the airbag11A is secured while simplifying the connection structure between the inflator66and the airbag11A and the assembly of the inflator66. As a result, the airbag device M2also reduces the number of steps and the cost of assembly.

In the second embodiment, too, the diffuser70of the inflator66is so mounted around the body portion67as to force the two ends70aand70bto contact with the body portion67. Therefore, the inflator66itself is compactly constructed without elongating its axial length.

In the second embodiment, moreover, the gas discharge ports68of the inflator66are arranged toward the front end67aof the body portion67. However, the gas outlet port73is arranged close to the middle of the axial direction of the inflator66, on the side away from the gas discharge ports68. With this construction, even the inflator66of the stored gas type can feed the inflating gas G smoothly into the airbag11A. In this inflator66, specifically, the activating lead wires53are connected to the end portion67a(or the front end66aof the inflator66), close to which the gas discharge ports68of the body portion67are arranged. The side of the end portion66bof the inflator66where no lead wire53is arranged, is inserted into the inlet side portion20of the connection port portion19so that the end portion66aof the inflator66, where the lead wires53are arranged, may be exposed from the opening20bof the inlet side portion20of the connection port portion19. Thus, the gas outlet port73of the diffuser70is smoothly opposed to the communication port21a.

In this second embodiment, too, the inlet side portion20of the connection port portion19of the airbag11A is arranged, like the airbag11, in the longitudinal direction of the vehicle V. Therefore, the inflator66is easily arranged in the thin roof side rail portion on the upper edge side of the windows of the vehicle V.

Still moreover, the inlet side portion20of the airbag11A is opened at both front and rear ends20aand20c, and is protruded to the front and rear sides above the outlet side portion21. Moreoever, the two sealed portions of the inlet side portion20on the inflator66are formed at the front and rear ends20aand20con either side of the outlet side portion21, and are pressed on the outer circumference of the inflator66in the circumferential direction. Therefore, the inlet side portion20of the inflator66can retain the sufficient sealing properties by the simple construction using the clamps55and55fixed by plastic deformation. Moreover, the inflator66can be inserted from either side of the front and rear ends20aand20cof the inlet side portion20thereby to increase the flexibility in connecting the inflator66and the airbag11A.

In the second embodiment, still moreover, the front and rear sides of the inflator66on either side of the outlet side portion21, that is, the outer circumference of the front end70aof the diffuser70and the outer circumference of the root portion67bof the body portion67, are mounted on the inner panel2on the side of the body1by means of the mounting brackets75and76. Therefore, the inflator66itself is stably mounted on the inner panel2. When the inflator66acts, moreover, the injection force of the inflating gas G applies a pressure on the outlet side portion21in the direction away from the inflator66. However, the inflator66is inserted into the inlet side portion20which is protruded to the front and rear sides of the inlet side portion20above the outlet side portion21. Therefore, the inflator66itself can suppress the movement of the inlet side portion20by the two end portions20aand20cof the inlet side portion20with the outlet side portion21in between, thereby to support the connection port portion19stably.

Here in the airbags11and11A of the first and second embodiments, the connection port portion19is formed into the T-shape, as viewed from the interior side, to open at the front and rear ends20aand20cof the inlet side portion20to be connected to the inflators36and66. As a connection port portion79of an airbag11B of a third embodiment shown inFIGS. 7 and 8, however, an inlet side portion80may be bent into an L-shape from an outlet side portion81. Specifically, this connection port portion79is provided with the outlet side portion81and the inlet side portion80. The outlet side portion81has a communication port81aopened in its lower end for communicating with the feed passage portion15in the inflation portion14of the airbag11B. The inlet side portion80is bent from the upper side of the outlet side portion81toward the front side of the vehicle V and is provided an opening80bin its front end80a. Here, the airbag11B is different in the construction of the connection port portion79and in the position of the mounting portions26, but the remaining constructions are similar to those of the airbags11and11A.

Moreover, an inflator86of this airbag device M3of the third embodiment is provided with a diffuser87and the body portion67identical to that of the second embodiment. The diffuser87is formed of a sheet metal into a generally cylindrical shape and is assembled with the body portion67to cover the gas discharge ports68of the body portion67and to have its two ends pressed on the outer circumference of the body portion67.

The diffuser87is provided close to its leading end (or front end)87awith a flange portion88protruded in the inner circumferential direction and on the side of its root portion (or rear end)87bwith a curved portion89, which is curved toward the inner circumference side and is forced into contact with the entire outer circumference of the body portion67. Below the vicinity of the side of the rear end87bof the diffuser87(or the rear end of the inflator86), moreover, there is formed a generally semispherical bulge90, which is protruded downward. This bulge90releases the inflating gas G downward or in the direction generally perpendicular to the axial direction of the body portion67and the diffuser87of the inflator86. The bulge90is provided with two gas outlet ports91and92, each of which is opened in a circular shape for discharging the inflating gas G. When the airbag device is mounted on the vehicle, more specifically, the gas outlet port91releases the inflating gas G obliquely, forward and downward to guide the gas G, through the communication port81aof the outlet side portion81of the connection port portion79, to the front of the feed passage portion15in the inflation portion14of the airbag11B. In the meantime, the gas outlet port92releases the inflating gas G obliquely, rearward and downward to guide the gas G, through the communication port81aof the outlet side portion81of the connection port portion79, to the rear of the feed passage portion15in the inflation portion14of the airbag11B.

Moreover, this diffuser87is provided with two brackets93for mounting the inflator86on the inner panel2by means of the bolts58. Each of these brackets93is provided with a mounting hole93afor inserting the bolt58thereinto.

The inflator86is assembled by arranging the O-ring44in the inner side face of the flange portion88and by mounting the curved portion89of the side of the root portion87bfrom the side of the front end67aof the body portion67. The flange portion88is put in contact with the outer circumference of the leading end67ainterposing the O-ring44, and the curved portion89is pressed against the outer circumference of the root portion67b. Thus, both front and rear ends87aand87bare connected with the outer circumference of the body portion67with good sealing properties. As a result, the inflator86is assembled.

For connecting the assembled inflator86to the connection port portion79, moreover, the root portion87bof the diffuser87is inserted, with the gas outlet ports91and92directed downward, from the opening80bof the front end80ainto the inlet side portion80in the connection port portion79of the airbag11B. Moreover, the vicinity of the front end portion80aof the inlet side portion80is forced, while being held by the clamps55, to contact with the vicinity of the longitudinal center of the inflator86, or the vicinity of the middle of the diffuser87and the flange88. Thus, the inflator86and the connection port portion79are connected.

At this connecting time, the airbag11B is folded as in the first embodiment, and has the mounting brackets33attached thereto. Moreover, the gas outlet ports91and92of the diffuser87face toward the communication port81aof the connection port portion79above the communication port81aand are arranged toward the feed passage portion15of the inflation portion14.

After the inflator86is connected to the connection port portion79, the airbag11B and the inflator86are mounted and fixed on the vehicle V by using the mounting bolts34and58, as in the first embodiment. Thus, the airbag device M3can be mounted on the vehicle V.

In this third embodiment, when the inflator86acts, the inflating gas G is discharged from the gas discharge ports68. And, the gas G is injected from the gas outlet ports91and92of the diffuser87through the clearance between the outer circumference of the body portion67and the inner circumference of the diffuser87and flows through the single connection port portion79near the longitudinal middle of the airbag11B to the front side and the rear side in the feed passage portion15of the inflation portion14in the airbag11B. Even if the outlet side portion81tries to leave the inflator86, the upper side inner circumference80cof the inlet side portion80is held firmly by the upper side outer circumference87cof the diffuser87of the inflator86, thereby to suppress the movement of the outlet side portion81. Therefore, the third embodiment achieves the same working-effects as those of the first embodiment, excepting that the inlet side portion80of the connection port portion79in the airbag11B is not provided with both front and rear openings on either side of the outlet side portion81.

In this third embodiment, the sealed portions on the outer circumference of the inflator86on the side of the end portion80aof the inlet side portion80are forced to contact in the circumferential direction with the outer circumference of the diffuser87. Moreover, the sealed portion of the diffuser87is spaced by a clearance S from the outer circumference of the body portion67. Even if the clamp55is fastened with more sealing pressure for sealing the inlet side portion80on the diffuser87than a predetermined level, therefore, the diffuser87is warped to narrow the clearance S in between the body portion67. As a result, the sealing pressure need not be strictly set, which facilitates the connecting work of the connection port portion79and the diffuser87.

Here, in the second embodiment, as shown inFIG. 6, the clearance S also is formed between the outer circumference of the body portion67and the inner circumference of the diffuser70at the connection portion by the clamps55between the diffuser70and the vicinity of the front end20aof the inlet side portion20of the connection port portion19. Therefore, the aforementioned working-effects are also attained in the second embodiment.

In the third embodiment, moreover, the connection port portion79of the airbag11B is formed into an L-shape, as viewed from the interior side, and is provided with the outlet side portion81extending upward from the inflation portion14and the inlet side portion80, bent to the front from the upper side of the outlet side portion81. However, the connection port portion79itself need not be formed into the L-shape, as long as it is formed, together with the airbag11B, of a flexible woven fabric. For example, the connection port portion may be projected either straight upward from the side of the upper edge11aof the airbag11B or obliquely forward or rearward while communicating with the inflation portion14. When mounted on the vehicle, then, the connection port portion thus formed may be bent in the L-shape to provide the side of the inflation portion14of the connection port portion as the outlet side portion, and the side connected to the inflator in which the inflator is inserted as the inlet side portion.

In the third embodiment, moreover, the connection port portion79of the airbag11B is formed into the L-shape, as viewed from the interior compartment, and the inflator86is mounted and fixed at its front end side by means of the brackets93and93. As in a fourth embodiment shown inFIGS. 9 and 10, however, an inflator96may be mounted and fixed on the inner panel2on the side of the body1at the both front and rear ends of the connection port portion79on either side of the outlet side portion81, even if this connection port79has an L-shape, as viewed from the interior compartment.

In this fourth embodiment, an airbag11C is closed on the side of the rear end80dapart from the opening80bin the inlet side portion80of the connection port portion79and protrudes to the rear end80dto the rear side of the outlet side portion81. In this point, the airbag11C differs from the connection port portion79of the airbag11B of the third embodiment, but the remaining constructions are similar to those of the airbag11B of the third embodiment.

And, the inflator96is provided with a diffuser97and the body portion67identical to that of the second and third embodiments. The diffuser97is formed of a sheet metal into a generally cylindrical shape to cover the gas discharge ports68of the body portion67, and is assembled with the body portion67by having its two ends forced into contact with the outer circumference of the body portion67.

The diffuser97is provided, on the side of its leading end (or front end)97a, with a flange portion98protruded to the inner circumference and, on the side of its root portion (or rear end)97b, with a curved portion99, which is so curved toward the inner circumference as to closely contact with the entire outer circumference of the body portion67. Below the vicinity of the longitudinal middle portion of the diffuser97, moreover, there is formed a bulge100which is protruded downward in a frusto-conical shape. In the slope of the bulge100, there are formed two gas outlet ports101and102opened in circular shapes. These gas inlet ports101and102release the inflating gas G individually downward or in the direction generally perpendicular to the axial direction of the body portion67and the diffuser97of the inflator96. When the airbag device is mounted on the vehicle, specifically, the gas outlet port101releases the inflating gas G obliquely, forward and downward. Thus, the released gas G is guided through the communication port81aof the outlet side portion81of the connection port portion79to the front side of the feed passage portion15in the inflation portion14of the airbag11C. The gas outlet port102releases the inflating gas G obliquely, rearward and downward. The released gas G is guided through the communication port81aof the outlet side portion81of the connection port portion79to the rear side of the feed passage portion15in the inflation portion14of the airbag11C.

The diffuser97is assembled with the body portion67by arranging the O-ring44in the inner side face of the flange portion98and by mounting the curved portion99of the side of the root portion97bover the body portion67from the side of the front end67a. And, the flange portion98is forced to contact with the outer circumference of the leading end67awhile interposing the O-ring44, and the curved portion99is pressed against the outer circumference of the root portion67b. Thus, the diffuser97is assembled with the body portion67while the front and rear ends97aand97bare finely sealed with the outer circumference of the body portion67. As a result, the inflator96is assembled.

For connecting the assembled inflator96to the connection port portion79, the root portion97bof the diffuser97is inserted, while the gas outlet ports101and102being directed downward, from the opening80bof the front end80ainto the inlet side portion80in the connection port portion79of the airbag11C. Then, the vicinity of the front end portion80aand the vicinity of the rear end portion80dof the inlet side portion80are forced, while being held by the holding portions76aof the mounting brackets76, into contact with the front and rear ends of the inflator96, i.e., the front and rear ends97aand97bof the diffuser97. Thus, the inflator96is connected to the connection port portion79.

At this connecting time, the airbag11C is folded as in the first embodiment, and has the mounting brackets33attached thereto. Moreover, the gas outlet ports101and102of the diffuser97face toward the communication port81aof the connection port portion79above the communication port81aand are arranged to face toward the feed passage portion15of the inflation portion14.

After the inflator96is connected to the connection port portion79, the airbag11C and the inflator96are mounted and fixed on the vehicle V by using the mounting bolts34and58, as in the first embodiment. Then, the airbag device M4is mounted on the vehicle V.

In this fourth embodiment, when the inflator96acts, the inflating gas G is discharged from the gas discharge ports68. Then, the gas G is injected from the gas outlet ports101and102of the diffuser97through the clearance between the outer circumference of the body portion67and the inner circumference of the diffuser97. Subsequently, the gas G flows through the single connection port portion79near the longitudinal middle of the airbag11C to the front and the rear of the feed passage portion15of the inflation portion14in the airbag11C. Even if pressure is applied to the outlet side portion81in the direction away from the inflator96, the upper side inner circumference80cof the inlet side portion80is held firmly by the upper side outer circumference97cof the diffuser97in the inflator96, thereby to suppress the movement of the outlet side portion81. Therefore, the fourth embodiment achieves the same working-effects as those of the first embodiment, although the inlet side portion80of the connection port portion79in the airbag11C is not provided with the two openings on the front and rear on either side of the outlet side portion81. Moreover, the inflator96can be stably mounted and fixed on the vehicle V.

Here, the gas outlet port to be formed in the diffuser of the inflator may enter into the side of the outlet side portion21in the connection port portion19of the airbag11A, as shown in FIG.11. This inflator106is constructed to include a body portion107and a diffuser113. The body portion107is formed into a cylinder type having gas discharge ports111open on the outer circumference for discharging the inflating gas G. The diffuser113is formed of a metal into a generally cylindrical shape which extends over the gas discharge ports111of the body portion107and is connected with the body portion107by pressing its two ends on the outer circumference of the body portion107.

The body portion107is of a stored gas type, charged with a cold gas, and is provided with a base portion108and a head portion109. The base portion108is formed into a generally cylindrical shape and is arranged on the side of the rear end107bof the body portion107. The head portion109is formed into a generally cylindrical shape having a slightly smaller diameter than the base portion108and is arranged on the side of the front end (or leading end)107aof the body portion107. The gas discharge ports111are arranged in the outer circumference close to the leading end109aof the head portion109, and the connector52for inputting action signals from the action circuit of an airbag device M5is connected to the leading end face of the head portion109. Close to the root portion109bof the head portion109, moreover, there is arranged a groove110, which extends in the entire circumferential direction, for mounting the diffuser113.

The diffuser113is formed of a sheet metal into a generally cylindrical shape and is provided, on the side of its leading end (or front end)113a, with a flange portion114protruded to the inner circumference and, on the side of its root portion (or rear end)113b, with a caulking portion115to be fitted in the groove110of the body portion107. On the front side of the caulking portion115, there is formed a cylindrical portion116with a bottom wall, which is protruded downward. The bottom wall116aof the cylindrical portion116is formed into a conical shape and is provided with two gas outlet ports117and118, which are opened in circular shapes. These gas outlet ports117and118release the inflating gas G downward or in the direction substantially perpendicular to the axial direction of the body portion107and the diffuser113of the inflator106. When the airbag device is mounted on the vehicle, specifically, the gas outlet port117releases the inflating gas G obliquely, forward and downward. The released gas G is guided through the communication port21aof the outlet side portion21of the connection port portion19to the front of the feed passage portion15in the inflation portion14of the airbag11A. The gas outlet port118releases the inflating gas G obliquely, rearward and downward. The released gas G is guided through the communication port21aof the outlet side portion21of the connection port portion19to the rear of the feed passage portion15in the inflation portion14of the airbag11A.

This diffuser113is connected with the body portion107by arranging the O-ring44on the inner face of the flange portion114and by mounting the diffuser on the head portion109of the body portion107from the side of the diffuser root portion113b. And, the flange portion114is applied to the outer circumference of the leading end of the head portion109while interposing the O-ring44, and the caulking portion115is fitted in the groove110. Then, the diffuser113is mounted on the body portion107while the front and rear ends113aand113bare finely sealed against the head portion109of the body portion107. As a result, the inflator106is assembled.

This inflator106is connected to the connection port portion19by means of the clamps55and55, as in the first embodiment, and is mounted and fixed on the vehicle V by means of the mounting brackets57.

The airbag device M5using this inflator106achieves the same working-effects as those of the first embodiment. In the airbag device M5, moreover, the gas outlet ports117and118are entered into the outlet side portion21of the connection port19and thus toward the inflation portion14of the airbag11A. Therefore, the inflating gas G coming from the gas outlet ports117and118smoothly flows through the communication port21aof the outlet side portion21in two oblique directions, i.e., forward and downward, and rearward and downward, into the feed passage portion15of the inflation portion14. Thus, the gas G quickly reaches the two longitudinal ends of the inflation portion14so that the quick expansion and inflation of the airbag11A is secured in the airbag device M5.

If the aforementioned point is not considered important, one gas outlet port for releasing the inflating gas G downward may be arranged in the bottomed cylindrical portion116which is protruded below the diffuser113.

On the other hand, the inflators36,66,86,96and106of the foregoing embodiments have been exemplified by the stored type, which are charged with a cold gas. However, the invention may use an inflator of the hybrid type or the like using reactive (or combustion) gas by chemical reactions.

Moreover, in the connection port portion of each airbag or in the vicinity of the communication port in the feed passage portion, there may be arranged, in addition to the diffuser, a flexible commutating cloth, which releases the inflating gas to the front and rear of the airbag, or to the three sides, i.e., to the front, rear and lower sides of the airbag.