Airbag and airbag device

In an airbag, an airbag main body is formed into a bag so as to comprise at least a front panel and a rear panel in an inflated and deployed state, vent holes are formed on the rear panel, vent covers that open and close the vent holes are attached to an outer surface of the rear panel, patch members are attached to the vent covers, and opening degrees of the vent holes are regulated by the vent covers and the patch members inflating in cooperation using a portion of the pressurized gas supplied to the interior of the airbag main body when the airbag main body inflates and deploys.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an airbag for ensuring the safety of an occupant in the event of collision of the vehicle or the like, and an airbag device that uses the same.

2. Description of the Related Art

There have heretofore been known airbag devices whereby an inflator activates in the event of an emergency, such as collision or rollover of the vehicle, and an airbag formed into a bag inflates and deploys from a folded state by pressurized gas jetted from this inflator, restraining the occupant.

The airbag used in the airbag device comprises an airbag main body formed into a bag so as to comprise at least a first panel and a second panel in the inflated and deployed state, and a vent hole formed on the second panel. When an occupant contacts the inflated and deployed airbag main body, the pressurized gas is made to discharge from the interior of the airbag main body via this vent hole. With this arrangement, it is possible to smoothly receive and hold the occupant by the airbag main body.

In recent years, there have been proposed airbags configured so that the vent hole is in a closed or slightly opening degree until the internal pressure of the airbag main body reaches a predetermined value or higher, and then is in an open or fully opening degree when the internal pressure of the airbag reaches the predetermined value or higher and an occupant contacts the airbag (refer to WO 2008/136336 and JP, A, 2008-308139, for example).

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In the art disclosed in WO 2008/136336, an opening/closing member provided on the outside of the vent hole is opened and closed by a tether that passes through the airbag interior when the airbag inflates and deploys. Accordingly, the operational behavior of the tether when the vent hole is opened and closed is easily affected by the pressurized gas, making it difficult to smoothly control the closed position of the vent hole with high accuracy. As a result, to ensure the internal pressure of the airbag main body with high accuracy, complex setups that decrease the capacity of the airbag main body, increase the jetting ability of the pressurized gas jetted from the inflator, and the like are necessary.

In the art disclosed in JP, A, 2008-308139, a dedicated opening/closing device for adjusting the opening degree of the vent hole is required. This results in an increase in the size of the airbag device in order to secure space for attaching the opening/closing device and, furthermore, an increase in the cost of the airbag device.

It is therefore an object of the present invention to provide an airbag and an airbag device capable of smoothly controlling the closed position of the vent hole with high accuracy using a relatively simple and low cost structure without complex setup.

Means for Solving the Problems

In order to achieve the above-described object, according to the first invention, there is provided an airbag comprising an airbag main body formed into a bag so as to comprise at least a first panel on a side facing an occupant and a second panel on a side not facing the occupant in an inflated and deployed state, at least one vent hole formed on the second panel, at least one vent cover that is attached to an outer surface of the second panel and opens and closes the vent hole, and at least one patch member that is joined to the vent cover between the second panel and the vent cover and has an opening that communicates with the vent hole.

According to the airbag of the first invention, the airbag main body is formed into a bag so as to comprise at least a first panel and a second panel in an inflated and deployed state, a vent hole is formed on the second panel, and a vent cover that opens and closes the vent hole is attached to an outer surface of the second panel.

Hence, when the inflator activates in the event of an emergency such as vehicle collision or rollover, the airbag formed into a bag inflates and deploys from a folded state into a bag shape by the pressurized gas jetted from this inflator, and an occupant contacts the inflated and deployed airbag main body, the airbag main body can receive and hold (restrain) the occupant.

Further, with the airbag main body inflated and deployed, the first panel here is a panel that constitutes the surface that faces (lines up with) the occupant, that is, the front surface that the occupant actually contacts (using the occupant as reference). Further, the second panel refers to a surface other than the first panel of the three-dimensional shape of the airbag main body when inflated and deployed into a bag shape and, according to the three-dimensional shape, refers to the bottom surface that serves as the back side of the front surface, or multiple surfaces such as the bottom surface, side surfaces, and the like.

Furthermore, according to the airbag of the first invention, a patch member is joined to the vent cover so as to be positioned between the second panel and vent cover, and an opening that communicates with the vent hole is provided on this patch member. Then, the opening degree of the vent hole is regulated using a portion of the pressurized gas supplied to the interior of the airbag main body when the airbag main body inflates and deploys. That is, when the pressurized gas is introduced into the interior of the airbag main body, the gas attempts to be released from the vent hole. Hence, the pressurized gas that attempts to be released is captured between the vent cover and patch member (specifically, a space for gas accumulation formed on the outer circumference side of the opening, between the vent cover and patch member). At this time, the joined body of the vent cover and patch member acts further on the outside than the opening that communicates with the vent hole so as to block the vent hole while inflating, making it possible to set the opening degree of the vent hole to a closed or slightly open state. With this arrangement, it is possible to maintain a high internal pressure of the airbag main body.

On the other hand, when an occupant contacts the airbag main body, the vent cover is pushed out by the pressure, making it possible to open the vent hole, vent the pressurized gas inside the airbag main body to the exterior, and smoothly receive and hold the occupant.

According to the second invention, in the airbag according to the first invention, the vent cover comprises a hinge part joined with the second panel on one side, and a regulating member that regulates an opening degree of the vent cover on the other side.

According to the airbag of the second invention, a hinge part joined with the second panel is provided on one side (the introduction direction downstream side of the pressurized gas introduced into the airbag main body, for example) of the vent cover. With this arrangement, it is possible to receive and hold the pressurized gas that is introduced into the airbag main body and attempts to leak from the vent hole by the hinge part, making it easier to suppress the opening of the vent cover and, at the same time, easier to inflate the airbag main body by the cooperation with the patch member. Further, a regulating member that regulates the opening degree of the vent cover is provided on the other side (that is, the reverse side of the hinge part) of the vent cover. With this arrangement, when the airbag main body inflates by the cooperation with the patch member, it is possible to press the patch member on the vent hole and more easily and highly ensure the sealing position of the vent hole.

According to the third invention, in the airbag according to the first or the second invention, the patch member communicates with the vent hole by a hole facing the vent hole serving as the opening, and is joined to the vent cover in an area that surrounds an outer circumference side of the hole.

Furthermore, according to the airbag of the third invention, the opening of the patch member is established as a hole facing the vent hole and, moreover, the patch member is joined to the vent cover in an area that surrounds the outer circumference side of the opening. Then, the opening degree of the vent hole is regulated using a portion of the pressurized gas supplied to the interior of the airbag main body when the airbag main body inflates and deploys. That is, when the pressurized gas is introduced into the interior of the airbag main body, the gas attempts to be released from the vent hole. Hence, the pressurized gas that attempts to be released is captured between the vent cover and patch member (specifically, a space for gas accumulation formed on the outer circumference side of the opening, between the vent cover and patch member). At this time, in particular, the patch member is joined to the vent cover so as to surround the opening facing the vent hole, thereby causing the pressurized gas that attempts to leak from the vent hole to be efficiently captured in the space for gas accumulation described above from the opening. As a result, the joined body of the vent cover and patch member acts so as to block the vent hole while inflating, making it possible to set the opening degree of the vent hole to a closed or slightly open state. With this arrangement, it is possible to maintain a high internal pressure of the airbag main body.

According to the fourth invention, in the airbag according to the second invention, the vent cover is formed into a substantially fan shape that is larger than the vent hole, with an arc-shaped part of one side thereof serving as the hinge part, the patch member is a substantially V- and strip-shaped member that extends along the other two sides of the vent cover, and an area near an outer edge of the strip-shaped member is joined with the vent cover and an inner edge side of the strip-shaped member is set as a free end.

According to the airbag of the fourth invention, a substantially V-shaped patch member is joined to a substantially fan-shaped vent cover, on the two sides of the remaining edges excluding the hinge part, making it possible to communicate with the vent hole using an inside part (interior angle side) sandwiched on the acute angle side by the V-shaped two sides of this patch member as an opening, and capture the pressurized gas that attempts to be released from the vent hole between the vent cover and patch member by the cooperation of the vent cover and patch member. Accordingly, a small substantially V-shaped patch member just needs to be disposed in only the part corresponding to the two sides that serve as the remaining edges excluding the hinge part, making it possible to reduce the material cost of the patch member.

According to the fifth invention, in the airbag according to the fourth invention, the vent cover is joined with the second panel so that an interior angle formed by line segments connecting a center of the vent hole and both ends of the hinge part is 180° or less.

According to the airbag of the fifth invention, it is possible to ensure a large opening area of the vent hole positioned further on the outside than the line that connects both ends of the hinge part (the strip-shaped member side opposite the hinge part), making it possible to ensure high venting efficiency of the pressurized gas from the vent hole.

According to the six invention, there is provided an airbag device in the first invention and an inflator that supplies a pressurized gas to the airbag.

According to the airbag device of the sixth invention, it is possible to apply the vent cover and patch member to the vent hole of an airbag device comprising an inflator that supplies pressurized gas to an airbag.

Advantages of the Invention

According to the airbag and airbag device of the present invention, it is possible to smoothly control the closed position of the vent hole with high accuracy using a relatively simple and low cost structure, without complex setup. This makes it possible to more easily vent the pressurized gas after an occupant contacts the airbag while maintaining a high internal pressure until the airbag is completely inflated and deployed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Next, the airbag and airbag device related to an embodiment of the present invention will be described with reference to accompanying drawings.

FIG. 1is an exploded perspective view of an airbag related to an embodiment of the present invention;FIG. 2is a front view of the assembled state of the main parts, showing an airbag related to an embodiment of the present invention;FIG. 3is an explanatory view of the relative positional relationship between the steering wheel and vent holes, showing an airbag related to an embodiment of the present invention;FIG. 4is a front view of the vent patch, showing an airbag related to an embodiment of the present invention;FIG. 5is a front view of the tether cover, showing an airbag related to an embodiment of the present invention;FIG. 6Ais a front view of the vent cover, andFIG. 6Bis a front view of the patch member, showing an airbag related to an embodiment of the present invention;FIG. 7is a front view of the vent cover with the patch member attached, showing an airbag related to an embodiment of the present invention;FIG. 8Ais a cross-sectional view of the main parts before inflation, andFIG. 8Bis a partial perspective view of the main parts before inflation, showing an airbag related to an embodiment of the present invention; andFIG. 9Ais a cross-sectional view of the main parts in a state of inflation, andFIG. 9Bis a partial perspective view of the main parts in a state of inflation, showing an airbag related to an embodiment of the present invention.

InFIG. 1andFIG. 2, an airbag10comprises a substantially perfectly circular front panel12serving as a first panel positioned on a side facing an occupant, and a rear panel14serving as a second panel positioned on a side not facing an occupant, having substantially the same diameter as the front panel12, and constitutes a bag-shaped airbag main body16with the peripheral edges thereof joined by stitching or the like. Note that, with the airbag main body16inflated and deployed, the front panel12serving as the surface facing the occupant constitutes the surface that faces (lines up with) the occupant, that is, the front surface that the occupant actually contacts (using the occupant as reference). Further, the rear panel14constitutes a surface, which excludes the front panel12, of the three-dimensional shape of the airbag main body16when inflated and deployed into a bag shape and, according to the three-dimensional shape, includes the side surfaces such as the side panels and the like.

An inflation control member18is disposed on the front panel12, near the center. This inflation control member18integrally comprises a joining part18athat is joined by stitching H1(shown by the double-dashed chain line inFIG. 1only) to the center of the front panel12, and a strip-shaped regulating part18bthat extends from the joining part18a.

A substantially triangular shaped vent patch20and a tether cover22are disposed on the inner surface of the rear panel14. Further, vent covers24and patch members26are disposed on the outer surface of the rear panel14.

An inflator insertion hole14ais formed near the center of the rear panel14. A pair of vent holes14bis formed on the rear panel14, on the vehicle body upward (frontward) side from the center of the rear panel14, in the state attached to the vehicle body (the state attached to the steering wheel). The vent holes14bare formed so that each comprises an opening center in a radial direction from the center of the rear panel14, and so that, for example, they are symmetrical in the 2 o'clock and 10 o'clock directions, using the short hand of the clock as reference, with respect to a center line (the 0 o'clock direction) of a steering wheel S that extends in the vehicle body front-rear direction, as shown inFIG. 3. Note that the vent holes14bare formed in the center of the rear panel14, that is, in positions near an inflator30of an inflator device, and are set so that venting is possible from the initial stage of deployment. At this time, the pair of vent holes14bis disposed in a space that avoids a spoke P that extends from near the center toward a wheel rim R of the steering wheel S, further on the inside than the wheel rim R. Further, the vent holes14bare disposed in positions capable of avoiding interference (overlap) between an opened airbag lid (not shown) formed on the steering wheel S and the vent holes14b. A pair of slits14cis formed on the rear panel14, in positions near the respective vent holes14b.

The vent patch20is formed from cloth of the same material as the front panel12and the rear panel14, in a substantially triangular shape with each corner area made into an arc shape, as shown inFIG. 4. A second inflator insertion hole20athat agrees with the aforementioned inflator insertion hole14a, a pair of vent holes20bthat agrees with the vent holes14b, and a pair of slits20cthat agrees with the respective slits14care formed on the vent patch20. The vent patch20is joined to the rear panel14by stitching H2, H3, H4in an annular (perfectly circular) manner so as to surround the second inflator insertion hole20a, for example. Further, the vent patch20is joined to the rear panel14by stitching H5in an annular (perfectly circular) manner so as to surround the vent hole20b. Furthermore, the vent patch20is extended so as to straddle the pair of slits20c, and is joined by parallel stitching H6, H7, sandwiching the slits20c.

The tether cover22is formed from cloth of the same material as the front panel12and the rear panel14, as shown inFIG. 5, forming a third inflator insertion hole22athat agrees with the inflator insertion hole14a, and a slit22bpositioned on the center line (0 o'clock direction) that extends in the vehicle body front-rear direction. Note that the tether cover22is atypically formed so as to avoid the vent holes20b, and the slit22bis formed so as to be positioned between the pair of slits20c. The tether cover22is integrally joined to the rear panel14with the vent patch20(by the stitching H2, H3, H6, H7). The tether cover22covers the slits20cof the vent patch20on both ends thereof, improving the seal integrity by blocking the communicated state with the exterior via the slits14cof the rear panel14.

The vent covers24, as shown inFIG. 6A, each comprise a fan-shaped cover24a, a strip-shaped tether24bthat extends from the cover24a, and a joining piece24cthat is wider than the tether24band positioned at the tip end of the tether24b. Note that the vent covers24are individually correspondingly disposed on the respective vent holes14b. At this time, the vent covers24used are identical in shape, size, and the like (apparently with the front and rear reversed in the attached state) and, as shown inFIG. 1, are symmetrically disposed with respect to each other. According to this embodiment, the pair of vent holes14bis symmetrically disposed with respect to the center line (0 o'clock direction). Accordingly, the pair of vent covers24is also symmetrically disposed with respect to the center line of the rear panel14(the airbag main body16). The arc-shaped peripheral edges of the covers24aof the vent covers24are each joined to the rear panel14by stitching H8, and the vent covers24each constitute a hinge part28by the stitching H8. Hence, the hinge parts28are each formed on the introduction direction (jetting direction) downstream side of the pressurized gas jetted from the inflator30disposed in the center of the rear panel14, that is, on the outer circumference side of the rear panel14. Accordingly, the arc centers of the hinge parts28are each preferably positioned on the extending line of the line that connects the center of the rear panel14and the center of the vent hole14b. The tethers24bare each inserted into the slit14cand the slit20cand then pulled out from the slit22bvia the area between the vent patch20and the tether cover22(between the stitching H6and the stitching H7), and subsequently the joining pieces24cof the respective ends are joined by stitching H9. The length of the tethers24bis set so as to regulate the opening degrees of the covers24ausing the slit22bas reference when the joining pieces24cthereof are joined. Further, the pair of tethers24bis joined with the tip end of the regulating part18bof the inflation control member18by the stitching H9, thereby regulating the thickness of the airbag main body16when the airbag main body16inflates and deploys, in accordance with the lengths of the pair of tethers24band the regulating part18b. Further, the tether24b, which is one end of the vent cover24, passes through the slit20cand the slit22b, thereby making the cloth of the slit20cless susceptible to stretching by the pressurized gas jetted from the inflator30, reducing gas leakage.

The patch member26, as shown inFIG. 6B, is formed into a fan shape, and an opening26ahaving a smaller diameter than that of the opening of the vent hole14bis formed in the center thereof According to this embodiment, as shown inFIG. 7, the patch member26is joined to the cover24aby the stitching H5so as to surround the opening26a.

In the above described configuration, as shown inFIGS. 8A and 8B, the covers24aand the patch members26are positioned so as to extend along the rear panel14in a stored state with the inflator30not activated.

When the inflator30activates and the pressurized gas is supplied to the interior of the airbag main body16, a portion thereof attempts to be released from the vent holes14bto the exterior. Hence, as the airbag main body16inflates, tension is applied to the regulating part18band the tethers24b, thereby producing tensile force and regulating the opening degrees of the covers24a. Further, a portion of the pressurized gas is supplied between the covers24aand the patch members26from the openings26aand, as shown inFIGS. 9A and 9B, the covers24aand the patch members26inflate in cooperation, pressing the vent holes14bwhile forming a space K between the covers24aand the patch members26for pressurized gas accumulation. Accordingly, by the inflation of the covers24aand the patch members26in addition to the regulation of the opening degrees of the covers24aby the tensile force of the tethers24bdescribed above, it is possible to highly maintain the seal integrity of the vent holes14b.

Further, the other end (the regulating part18b) of the inflation control member18that regulates thickness when the airbag main body16inflates and deploys, and both ends (the joining pieces24c) of the tethers24bare joined, making it possible to regulate thickness during inflation of the airbag main body16by the entire length of the regulating part18band the tethers24band, with the pulling action produced on the tethers24bby the inflation and deployment of the airbag main body16, press the vent covers24in the closing direction of the vent holes14b.

As described above, according to the airbag10in this embodiment, the airbag main body16is formed into a bag so as to comprise at least the front panel12and the rear panel14in an inflated and deployed state, the vent holes14bare formed on the rear panel14, the vent covers24that open and close the vent holes14bare attached to the outer surface of the rear panel14, the patch members26are attached to the vent covers24, and the opening degrees of the vent holes14bare regulated by the vent covers24and the patch members26inflating in cooperation using a portion of the pressurized gas supplied to the interior of the airbag main body16when the airbag main body16inflates and deploys. That is, when the pressurized gas is introduced into the interior of the airbag main body16, the gas attempts to leak out from the vent holes14b.

Hence, the pressurized gas that attempts to leak out is captured between the vent covers24and the patch members26(specifically, in spaces K for gas accumulation that are formed on the outer circumference side of the above described openings26a, between the vent covers24and the patch members26) from the openings26a. At this time, in particular, the patch members26each comprise the opening26afacing the vent hole14band are joined to the vent cover24so as to surround the opening26a, thereby efficiently capturing the pressurized gas that attempts to leak from the vent hole14bin the above described space K for gas accumulation from the opening26a. As a result, each joined body of the vent cover24and the patch member26acts so as block the vent hole14bwhile inflating, making it possible to set the opening degree of the vent hole14bto a closed or slightly open state and maintain the high internal pressure of the airbag main body16.

Note that the joining pieces24cof the pair of tethers24band the tip end of the regulating part18bare joined, thereby causing a pulling action to be produced on the tethers24bwhen the airbag main body16inflates and deploys, and the vent covers24to press in the closing direction of the vent holes14b. Further, the joining pieces24cof the pair of tethers24bare joined together, causing the pair of vent holes14bto operate simultaneously, making it possible to make the opening degrees of the pair of vent holes14buniform. At this time, the inflation control member18and the slit22bof the tether cover22are disposed in the center (0 o'clock direction), making it possible to even more easily make the opening degrees of the pair of vent holes14buniform with both serving as mutual targets.

On the other hand, when an occupant contacts the airbag main body16, the vent covers24are pressed by the pressure, making it possible to open the vent holes14b, release the pressurized gas inside the airbag main body16to the exterior, and smoothly receive and hold the occupant.

Further, in particular, according to this embodiment, the vent covers24each comprise the hinge part28joined with the rear panel14on the introduction direction downstream side of the pressurized gas introduced into the interior of the airbag main body16, thereby making it possible to receive and hold the pressurized gas that is introduced into the airbag main body16and attempts to leak from the vent hole14bby the hinge part28. Further, this makes it possible to easily suppress the opening of the vent covers24and, at the same time, more easily inflate the airbag main body16by the cooperation of the vent covers24and the patch members26.

Further, in particular, according to this embodiment, the tethers24bserving as regulating members that regulate the opening degrees of the vent covers24are disposed on the vent covers24on the reverse side of the hinge part28, making it possible to press the patch members26on the vent holes14bwhen inflated by the cooperation with the patch members26, and easily and highly ensure the sealing positions of the vent holes14b.

Modification

However, while the patch member26that forms the opening26afrom a hole having a smaller diameter than the vent hole14bis indicated in the above described embodiment, the opening26adoes not need to be a hole.FIGS. 10-15show an airbag related to a modification of an embodiment of the present invention, wherein:FIG. 10is an exploded perspective view of an airbag related to a modification;FIG. 11Ais an exploded perspective view of the main parts, andFIG. 11Bis a front view of the main parts, showing an airbag related to a modification;FIG. 12Ais a front view of the vent cover, andFIG. 12Bis a front view of the patch member, showing an airbag related to a modification;FIG. 13is a front view with the patch member attached to the vent cover, showing an airbag related to a modification;FIG. 14Ais a cross-sectional view of the main parts before inflation,FIG. 14Bis a cross-sectional view of the main parts in a state of inflation, andFIG. 14Cis a partial perspective view of the main parts in a state of inflation, showing an airbag related to a modification; andFIG. 15is an action explanatory view showing an airbag related to a modification. Note that, inFIGS. 10-15, components identical to those in the above described embodiment are denoted using the same reference numerals, and descriptions thereof are omitted.

As shown inFIG. 10andFIG. 11, a patch member36is disposed between the rear panel14and the vent cover24(cover24a). The patch member36is a substantially V- and strip-shaped member that extends along the other two sides of the cover24a, excluding the arc-shaped side that is joined with the rear panel14by the stitching H8.

The area near the outer edge of the patch member36, as shown inFIG. 12andFIG. 13, is joined to the above described other two sides of the cover24aby stitching H10so that the inner edge side (the vent hole14bside) is a free end. Note that the angle of the interior angle resulting from the two sides of the patch member36is arbitrary, according to the shape and the like of the cover24a. Further, the patch member36establishes the interior angle side resulting from the above described other two sides where the vent hole14bis positioned as an opening36a.

At this time, for example, the inner edge of the patch member36and the opening edge of the vent hole14bmay tangentially overlap as shown inFIG. 11B, a portion of the inner edge side of the patch member36may enter the opening of the vent hole14bas shown inFIG. 14A, and the overall patch member36may be separated from the vent hole14bas shown inFIG. 15. In other words, the patch member36used may be the same regardless of the size of the vent hole14b.

In the configuration of this modification such as described above, the covers24aand the patch members36are positioned so as to extend along the rear panel14, as shown inFIG. 14A, in a stored state with the inflator30not activated.

When the inflator30activates and the pressurized gas is supplied to the interior of the airbag main body16, a portion thereof attempts to be released from the vent holes14bto the exterior. Hence, a portion of the pressurized gas is supplied between the covers24aand the patch members36from the openings36aand, as shown inFIG. 14BandFIG. 14C, the cover24aand the patch member36inflate in cooperation, regulating the opening degrees so that the vent holes14bare in a closed or slightly open state. Further, the opening degrees of the covers24aare regulated by the tensile force of the tethers24band the covers24aare pressed toward the vent holes14b, making it possible to highly maintain the sealing positions of the vent holes14b.

Further, the other end (the regulating part18b) of the inflation control member18that regulates thickness when the airbag main body16inflates and deploys, and both ends (the joining pieces24c) of the tethers24bare joined, making it possible to regulate the thickness of the airbag main body16by the entire length of the regulating part18band the tethers24band, with the pulling action produced on the tethers24bby the inflation and deployment of the airbag main body16, press the vent covers24in the closing direction of the vent holes14b.

At this time, since there is little resistance to venting the pressurized gas in the interior of the airbag main body16when contacted by the occupant, the patch members36can efficiently vent the pressurized gas from the vent holes14b. Moreover, the patch members36do not substantially interfere with the vent holes14bdirectly and therefore do not become a factor in hindering venting, making it possible to improve the robustness during venting.

Hence, the vent covers24during gas venting open with the line that connects the areas near both ends of the stitching H8that joins the vent covers24with the rear panel14(refer to the imaginary line L inFIG. 15) as the center, for example. As a result, a distance W′ from the outer side edge to the inner side edge of the strip-shaped patch member36in the direction extending along this center (the imaginary line L) can be shortened compared to a distance W (refer toFIG. 7) in the case of the patch member26.

That is, the diameter of the opening26aof the patch member26is set smaller than the diameter of the vent hole14b. On the other hand, a portion of the inner edge of the patch member36either enters the vent hole14b(FIG. 14), contacts the opening edge of the vent hole14b(FIG. 11), or is separated from the vent hole14b(FIG. 15), thereby making the distance W′ in the case of the patch member36shorter than the distance W in the case of the patch member26. Thus, the patch members36make it possible to easily open the vent covers24and decrease the venting resistance with respect to the pressurized gas that enters the spaces K (refer toFIG. 14B) during inflation by the cooperation of the rear panel14and the cover parts24a. Accordingly, it is possible to smoothly vent the pressurized gas from the vent holes14bvia the spaces K from the interior of the airbag main body16. Moreover, the area ratio of the opening area of the vent hole14band the overall area of the patch member36is small compared to the area ratio of the opening area of the vent hole14band the overall surface of the patch member26. This makes it possible to reduce the material cost of the patch member36to a greater degree than the patch member26.

Furthermore, as shown inFIG. 15, the patch member36makes it possible to make a distance A′ from a boundary part between the cover24aand the tether24bto the inner edge of the nearest patch member36shorter than a distance A (refer toFIG. 7) in the case of the patch member26. Accordingly, it is possible to decrease the venting resistance of the patch member36with respect to the pressurized gas near a pulling action point (the boundary part between the cover24aand the tether24b) that regulates the opening degree of the cover24a. With this arrangement, the pressurized gas is efficiently vented from the area near this pulling action point, which is also near the arc center of the hinge part28(the stitching H8).

At this time, for example, as shown inFIG. 11B, an interior angle θ formed by line segments that connect a center Q of the vent hole14band both ends of the stitching H8that forms the hinge part28is set to 180° or less, thereby making it possible to ensure a larger opening area of the vent hole14bfacing the part positioned further on the outside than the line connecting both ends of the hinge part28, that is, on the side opposite the hinge part28of the cover24aof the vent cover24, and thus ensure high venting efficiency of the pressurized gas from the vent hole14b.

Note that, as shown inFIG. 16, if the interior angle θ formed by the line segments that connect the center Q of the vent hole14band both ends of the stitching H8that forms the hinge part28is set to a more acute angle, it is possible to ensure even higher venting efficiency of the pressurized gas from the vent hole14b.

Note that while the above embodiments and modification have described illustrative scenarios in which the configuration of the airbag10that uses the patch members26,36of the present invention is applied to the airbag10of a driver airbag device assembled to the steering wheel, the present invention is not limited thereto. That is, the configuration of the airbag10that uses the patch members26,36of the present invention can be applied to a general airbag that comprises a vent hole, such as an airbag of an airbag device for a passenger seat comprising a side panel (a side surface), and an airbag of a variety of airbag devices, such as a side airbag device and the like.

Furthermore, while the embodiment and modification described above are preferred examples of the present invention, the present invention is not limited thereto, and various modifications may be further made without deviating from the spirit and scope of the present invention.