Airbag device

An airbag device includes an airbag, a blocking member that can adjust an exhaust hole of the airbag to a blocked state and an opened state, a coupling member, and a holding and releasing unit, which maintains a state of blocking the exhaust hole by holding the coupling member. When the holding and releasing unit releases the holding of the coupling member, the blocking member inverts in such a way as to be fed out from an inner peripheral face side of the airbag to an outer peripheral face side through the exhaust hole owing to being pressed by inflating gas, and causes inflating gas to be discharged from a through hole formed between leading end regions of outer peripheral edges of a first panel portion and a second panel portion in the blocking member and a communication hole communicating with the exhaust hole.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent Application No. 2021-196914 of Suzuki et al, filed on Dec. 3, 2021, the disclosures of which are hereby incorporated into the present application by reference.

BACKGROUND

Technical Field

The present invention relates to an airbag device such that an internal pressure of an airbag can be adjusted when the airbag inflates by discharging an inflating gas from an internal pressure adjustment exhaust hole provided in a peripheral wall of the airbag.

Description of Related Art

An existing configuration including an airbag having an exhaust hole through which an inflating gas can be discharged to adjust internal pressure in a peripheral wall, a blocking member that can adjust the exhaust hole to a blocked state and an opened state, and an actuator that maintains a state wherein the exhaust hole is blocked by holding a leading end portion side of a coupling member whose base portion side is coupled to the blocking member, and shifts the exhaust hole to an opened state by releasing the holding of the leading end portion side of the coupling member, is known as an airbag device (for example, refer to U.S. Pat. No. 8,646,808).

The blocking member is a tubular member whose leading end is opened, is disposed on an inner peripheral face side of the airbag by being pulled by the coupling member when the exhaust hole is blocked, and extends from a peripheral edge of the exhaust hole. The blocking member is such that when blocking the exhaust hole, a peripheral wall of the blocking member is flattened by the pressure of inflating gas in the airbag, thereby blocking the exhaust hole. Also, by the actuator releasing a holding of the leading end portion of the coupling member, the blocking member inverts in such a way as to be fed out to an outer side from the inner side of the airbag in a region of the exhaust hole by the pressure of the inflating gas, and discharges inflating gas from the tubular opened leading end portion, switching the exhaust hole to an opened state and causing the internal pressure of the airbag to decrease.

However, the existing configuration is such that as the blocking member is tubular when the exhaust hole is switched to an opened state, inflating gas can only be discharged from an aperture in the leading end after a whole of the blocking member is fed out to the outer side of the airbag, and there is room for improvement in a prompt discharge of inflating gas.

SUMMARY

An object of the invention is to provide an airbag device such that an airbag ensures good airtightness when an internal pressure adjustment exhaust hole is blocked, and an inflating gas can be discharged promptly when the exhaust hole is opened.

A representative configuration of an airbag device according to the invention is as follows.

The airbag device includes:

an airbag having, in a peripheral wall, an exhaust hole through which an inflating gas can be discharged in order to adjust internal pressure;

a blocking member, which is formed of a sheet material having flexibility and which can adjust the exhaust hole to a blocked state and an opened state;

a coupling member whose base portion side is coupled to the blocking member, the coupling member being inserted from an interior of the airbag to an exterior through an insertion hole formed in a peripheral edge of the exhaust hole of the airbag; and

a holding and releasing unit, which maintains a state of blocking the exhaust hole by holding a leading end portion side of the coupling member, and causes a shift to a state of opening the exhaust hole by releasing the holding of the leading end portion side of the coupling member, wherein

the blocking member in a state of blocking the exhaust hole includes:

a first panel portion that extends to the insertion hole side from the peripheral edge of the exhaust hole on an inner peripheral face side of the airbag, the first panel portion having a communication hole that communicates with the exhaust hole, and a peripheral edge of the communication hole being joined to the peripheral edge of the exhaust hole;

a second panel portion that coincides with a whole perimeter of an outer peripheral edge of the first panel portion and covers the exhaust hole and the first panel portion, the base portion side of the coupling member being coupled to leading end regions of outer peripheral edges of the first panel portion and the second panel portion in proximity to the insertion hole; and

a through hole, formed between the leading end regions and the communication hole, through which inflating gas can be caused to flow, and wherein

the blocking member

blocks the exhaust hole owing to the first panel portion and the second panel portion, which are positioned one on the other, being pressed to the inner peripheral face side of the airbag on the peripheral edge of the exhaust hole by inflating gas when the holding and releasing unit is holding the leading end portion side of the coupling member, and

inverts in such a way as to be fed out from the inner peripheral face side of the airbag to an outer peripheral face side through the exhaust hole and the communication hole owing to being pressed by inflating gas, causing inflating gas to be discharged from the through hole, when the holding and releasing unit releases the holding of the leading end portion side of the coupling member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention are described below with reference to accompanying drawings. However, the invention is not limited to the embodiments disclosed herein. All modifications within the appended claims and equivalents relative thereto are intended to be encompassed in the scope of the claims.

Hereafter, one embodiment of the invention will be described, using the drawings. An airbag device10of the present embodiment is a driver's seat airbag device10mounted to a steering wheel W, as shown inFIGS.1,2, and3. The steering wheel W includes a steering wheel main body1and the airbag device10, which is disposed on an upper portion of a boss portion B in a center of the steering wheel main body1. The steering wheel main body1includes a circular ring portion R, which is gripped when steering, the boss portion B, which is disposed in a center of the ring portion R and fastened to a steering shaft SS, and four spoke portions S that couple the boss portion B and the ring portion R.

In the following description, unless specifically stated otherwise, an up-down direction corresponds to an up-down direction along an axial direction of the steering shaft SS, a front-back direction corresponds to a front-back direction perpendicular to the axial direction of the steering shaft SS when a vehicle is steered straight ahead, and a left-right direction corresponds to a left-right direction perpendicular to the axial direction of the steering shaft SS when the vehicle is steered straight ahead.

The vehicle has a control device90that controls an operation of the airbag device10, a collision detecting sensor91that detects a collision, a position detecting sensor92that detects a position of an occupant (driver) MD (M, F) seated in a seat SE, and a weight detecting sensor93that detects a body weight of the occupant (driver) MD (M, F). On detecting a collision of the vehicle based on a signal output from the collision detecting sensor91, the control device90causes an inflator18to operate in order to cause an airbag30of the airbag device10to inflate. At this time, when determining, based on signals output from the position detecting sensor92and the weight detecting sensor93, that an internal pressure of the airbag30is not to be reduced, the control device90controls in such a way as not to cause an actuator62of an internal pressure adjusting mechanism48to operate. Also, when determining, based on signals output from the position detecting sensor92and the weight detecting sensor93, that the internal pressure of the airbag30is to be reduced, the control device90controls in such a way as to cause the actuator62of the internal pressure adjusting mechanism48to operate. For example, when the body weight of the driver MDF is light, or when the driver MDF is in proximity to the steering wheel W, the control device90determines that the internal pressure of the airbag30is to be reduced, and causes the actuator62to operate, thereby causing an inflating gas to be discharged from the airbag30in order to reduce the internal pressure of the airbag30. For example, when the body weight of the driver MDF is heavy, or when the driver MDF is distanced from the steering wheel W, the control device90determines that the internal pressure of the airbag30is not to be reduced, and maintains the internal pressure of the airbag30without causing the actuator62to operate.

As shown inFIGS.1,2, and3, the steering wheel main body1includes a metal core member2, of an aluminum alloy or the like, that couples the ring portion R, the boss portion B, and the spoke portion S. A region of the core member2in the ring portion R (a ring core member portion4) and a region on the ring portion R side of each spoke portion4are covered with a cover layer7made of a synthetic resin. A steel boss3afor inserting the steering shaft SS and fixing with a nut N is disposed in a boss core member portion3of the core member2in the boss portion B. Also, a lower cover8made of a synthetic resin, which covers a portion below the boss portion B, is disposed in a lower portion of the steering wheel main body1.

As shown inFIGS.3and4, the driver's seat airbag device10includes the airbag30, which is folded and housed, and which inflates owing to inflating gas being caused to flow thereinto in such a way as to be capable of protecting the driver MD (M, F), the inflator18, which supplies inflating gas to the airbag30, an airbag cover20that covers a portion above the folded airbag30, an attachment plate11that holds the airbag30, the inflator18, and the airbag cover20, and a retainer24for attaching the airbag30to the attachment plate11together with the inflator18. Also, the airbag device10includes the internal pressure adjusting mechanism48, which can adjust the internal pressure of the inflated airbag30. The internal pressure adjusting mechanism48includes a blocking member50, a blocking tether60acting as a coupling member coupled to the blocking member50, and the actuator62, which acts as a holding and releasing unit that carries out a holding and a releasing of a holding of the blocking tether60.

The retainer24is a metal plate of a quadrilateral ring form. The retainer24is configured to include a bolt25fixed with a nut26to the attachment plate11in each of four corners (refer toFIG.5) in such a way as to attach the airbag30to the attachment plate11by pressing a peripheral edge of an inflow aperture34, to be described hereafter, of the airbag30, and to attach the inflator18to the attachment plate11.

The inflator18includes a cylindrical main body portion18a, which includes a multiple of gas discharge ports18bin an upper portion thereof, and a flange portion18cprotruding from an outer peripheral face of the main body portion18a. Through holes (not shown) through which the bolts25of the retainer24are caused to pass are formed in the flange portion18c.

As shown inFIGS.2and3, the attachment plate11is a metal plate of an approximately rectangular form, is disposed in an upper portion of the boss portion B of the steering wheel W, and is a member to which the folded airbag30, the inflator18, and the airbag cover20are attached. An insertion hole12into which the main body portion18aof the inflator18can be inserted from below is opened in a circular form in the attachment plate11. A through hole (not shown) through which the bolt25of the retainer24is passed is formed in a periphery of the through hole12of the attachment plate11. Also, a multiple (three in the embodiment) of engagement legs16for attaching the airbag device10to an attachment portion5of the steering wheel main body1are attached to the attachment plate11. Each engagement leg16is configured in such a way as to incorporate a horn switch mechanism, and when an operation of pressing the airbag device10down is carried out after the airbag device10is attached to the steering wheel main body1, a horn provided in the vehicle can be operated. The engagement leg16is attached to the attachment portion5, which is provided in the boss core member portion3of the steering wheel main body1. By so doing, the airbag device10is attached to the steering wheel main body1.

Also, the actuator62of the internal pressure adjusting mechanism48is fixed to a back face of a front edge11aside of the attachment plate11. Also, an insertion hole14for inserting the blocking tether60, which is engaged with an engagement pin62bof the actuator62, through is provided in the attachment plate11(refer toFIGS.4and5).

Also, the attachment plate11includes a multiple of engagement holes13in which unshown engagement legs extending from a side wall portion22of the airbag cover20are engaged. The airbag cover20is engaged with the engagement holes13, and held by the attachment plate11.

The airbag cover20is made of a synthetic resin, and includes a ceiling wall portion21, which covers a portion above the airbag30folded and housed, and a side wall portion22, of an approximately square tube form, that extends downward from a vicinity of an outer peripheral edge of the ceiling wall portion21. Two door portions21a, which open at both front and back sides owing to being pushed by the inflating airbag30, are formed in the ceiling wall portion21(refer toFIG.2). As already described, engagement legs (not shown) engaged in the engagement holes13of the attachment plate11are disposed at a lower end of the side wall portion22.

The airbag30is formed of a fabric obtained by weaving strands of a polyamide, polyester, or the like. As indicated by two-dot chain lines inFIGS.1and2, a form of the airbag30when inflation is completed is configured in such a way as to be circular when seen from above, and approximately elliptical when seen from a side. An outer peripheral wall31of the airbag30includes a vehicle body side wall portion33on the steering wheel main body1side (the ring portion R side) and a driver side wall portion41on the driver MD side.

The vehicle body side wall portion33and the driver side wall portion41are both circular, and have identical external forms (refer toFIG.9). An inflow aperture34opened in a circular form, for causing inflating gas to flow in, is formed in a center of the vehicle body side wall portion33. The outer peripheral wall31is formed by outer peripheral edges of the vehicle body side wall portion33and the driver side wall portion41being sewn together. Also, attachment holes35through which the bolts25of the retainer24for attaching the airbag30to the attachment plate11are caused to pass are formed in a peripheral edge of the inflow aperture34(refer toFIG.9).

A reinforcing fabric72is sewn to the peripheral edge of the inflow aperture34, and the inflow aperture34and the attachment holes35are also formed in the reinforcing fabric72.

Also, two thickness regulating tethers44that couple the vehicle body side wall portion33and the driver side wall portion41are provided in the airbag30in order to regulate a distance between the vehicle body side wall portion33and the driver side wall portion41when inflating. The thickness regulating tether44is formed by an arm portion45b, which extends from both sides of a circular central portion45aof a lower side portion45sewn to the peripheral edge of the inflow aperture34of the vehicle body side wall portion33, and an arm portion46b, which extends from both sides of a disk-shaped central portion46aof an upper side portion46sewn to a central portion42of the driver side wall portion41, being sewn together. In the case of the embodiment, the central portion45aof the lower side portion45is also used as the reinforcing fabric72.

Also, two gas release holes36(vent holes) and an exhaust hole38(a variable vent hole) are provided in the vehicle body side wall portion33. The gas release hole36is a hole for releasing inflating gas in order to restrict a sudden rise in internal pressure in the airbag30when inflating gas flows in, is disposed on the left and right on a front portion side of the vehicle body side wall portion33, and is opened in a circular form. The exhaust hole38is a hole through which inflating gas can be discharged in order to adjust the internal pressure of the airbag when inflating, is disposed in a left-right direction center on a front portion side of the inflow aperture34, and is opened in an approximately elliptical form extended in the left-right direction. Furthermore, an insertion hole39, which is a slit-form aperture through which the blocking tether60is inserted, is provided in a position between the exhaust hole38and the inflow aperture34in the vehicle body side wall portion33. The exhaust hole38is set in such a way as to be disposed in a space FP between a front side portion1R of the ring portion R of the steering wheel W and the boss portion B when inflation of the airbag30is completed (refer toFIGS.10A and10B). Also, reinforcing fabrics73and74are sewn to peripheral edges of the gas release hole36and the exhaust hole38respectively.

The blocking member50configuring the internal pressure adjusting mechanism48is disposed on a peripheral edge of the exhaust hole38on an inner peripheral face30bside of the airbag30. The blocking member50is formed of the same kind of fabric (a sheet material) having flexibility, such as a polyamide, as the airbag30. As shown inFIGS.6to8C, the blocking member50includes, in a state of blocking the exhaust hole38, a first panel portion51, which extends from the peripheral edge of the exhaust hole38toward the insertion hole39at the rear thereof on the inner peripheral face30bside of the airbag30, and a second panel portion56, which is of the same external form as the first panel portion51, coincides with a whole circumference of an outer peripheral edge51aof the first panel portion51, and is disposed in such a way as to cover the exhaust hole38and the first panel portion51. A base portion60aside of the blocking tether60is coupled to a leading end region50bof the blocking member50in proximity to the insertion hole39. The blocking tether60is coupled between the first panel portion51and the second panel portion56when outer peripheral edges55aand56aof the first panel portion51and the second panel portion56are joined together.

The first panel portion51has a communication hole52that communicates with the exhaust hole38, and is joined to a peripheral edge of the exhaust hole38, with a peripheral edge of the communication hole52as a joint portion53. Also, a through hole54through which inflating gas can pass is formed in the first panel portion51, penetrating front and back, in a position between a leading end region51c(50b) coupled to the blocking tether60and the communication hole52.

The through hole54is provided in a position in the first panel portion51when flattened that is in proximity to the communication hole52between the leading end region51cand the communication hole52. As a ratio (H0:H1) of a distance H0between the communication hole52and the through hole54to a distance H1between the leading end region51cand the through hole54is 1:1.5, the through hole54is nearer to the communication hole52side than to the leading end region51c(refer toFIGS.11A and11B). Also, in a state wherein the first panel portion51is flattened, the through hole54is of an elliptical form extended in a direction WD perpendicular to a disposition direction SD of the leading end region51cand the communication hole52.

Also, in a state wherein the first panel portion51is flattened, the through hole54is disposed in a region CA between straight lines LF and LR, one on either side, which link two edges53aand53bof the joint portion53, which is joined to the peripheral edge of the exhaust hole38, in the width direction WD along a direction perpendicular to the disposition direction SD of the leading end region51cand the communication hole52, and two edges51caand51cbof a region communicating with a blocking tether60in the leading end region51c, respectively (refer toFIG.7).

In the embodiment, the blocking member50is formed of one sheet-form blocking member base fabric79, which is formed of a fabric such as a polyamide, as shown inFIG.9. The blocking member50is formed by, when the blocking member base fabric79is folded in two along a crease79a, a first panel region80that forms the first panel portion51and a second panel region81that forms the second panel portion56, which are of the same form, being positioned one on the other, and the outer peripheral edges51aand56aof the first panel portion51excepting the crease79aand the second panel portion56being sewn together. The peripheral edge of the communication hole52of the first panel portion51is joined by sewing to the peripheral edge of the exhaust hole38before the outer peripheral edges51aand56aare sewn together, and when the outer peripheral edges51aand56aare sewn together, the base portion60aof the blocking tether60is also sewn to the leading end region50b, whereby the blocking tether60is coupled to the blocking member50.

The blocking tether60is a strip-form member formed of a fabric (a sheet material) having flexibility, such as a polyamide. The base portion60a, which is one end portion of the blocking tether60, is joined to the leading end region50bof the blocking member50, and a leading end portion60b, which is another end portion, is held by the actuator62. An engagement hole60cinto which the engagement pin62bof the actuator62is inserted is formed in the leading end portion60b. The blocking tether60is held by the actuator62owing to the engagement pin62bof the actuator62being inserted into and engaged by the engagement hole60c, and the holding by the actuator62is released by the engagement pin62bbeing removed from the engagement hole60c. Also, an intermediate portion60dof the blocking tether60is inserted through the insertion hole39of the airbag30, and the leading end portion60bside is inserted through the insertion hole14of the attachment plate11. By so doing, the blocking tether60is inserted via the insertion hole39from the inner peripheral face30bside (an interior) of the airbag30to an outer peripheral face30aside (an exterior), and engaged to the engagement pin62bof the actuator62.

The actuator62incorporates a micro gas generator, and on receiving an operation signal from the control device90, instantaneously operates in such a way as to draw in the engagement pin62bprotruding from a main body62a. On the engagement pin62bbeing drawn in, the engagement pin62bcomes out of the engagement hole60c, and the holding of the blocking tether60by the actuator62is released.

As shown inFIG.9, materials configuring the airbag30are a vehicle body side base fabric70configuring the vehicle body side wall portion33, a driver side base fabric71configuring the driver side wall portion41, the reinforcing fabrics72,73, and74, a lower side portion76and an upper side portion77configuring the thickness regulating tether44, the blocking member base fabric79configuring the blocking member50, and a coupling member base fabric83. Manufacturing of the airbag30is such that, firstly, the lower side portion76doubling as the reinforcing fabric72, and the reinforcing fabrics73and74, are sewn to an inner peripheral side of the vehicle body side base fabric70forming the vehicle body side wall portion33. Also, the blocking member base fabric79is sewn to a position that is to become the exhaust hole38, and the inflow aperture34, the attachment hole35, the gas release hole36, the exhaust hole38, and the insertion hole39are formed by a hole opening process. When implementing the hole opening process for the exhaust hole38, the communication hole52is formed in the blocking member base fabric79. Also, the through hole54is formed in advance in the blocking member base fabric79.

Next, the crease79aof the blocking member base fabric79is applied, and the first panel region80and the second panel region81are positioned one on the other. At this time, the base portion60aof the blocking tether60is disposed between the first panel region80and the second panel region81, and the outer peripheral edges51aand56aare sewn together, thereby forming the blocking member50to which the blocking tether60is coupled. The leading end portion60bside of the blocking tether60is extruded to an outer surface side of the vehicle body side base fabric70from the insertion hole14.

Next, outer surface sides of the driver side base fabric71, to which the upper side portion77of the upper side portion46of the thickness regulating tether44is sewn, with an upper side portion reinforcing fabric75interposed in advance, and the vehicle body side base fabric70are brought together, and outer peripheral edges are sewn together, and the driver side base fabric71and the vehicle body side base fabric70are caused to invert utilizing the inflow aperture34. By so doing, the outer peripheral wall31of the airbag30is formed. Subsequently, utilizing the inflow aperture34, the airbag30can be manufactured by the arm portions (45band46b)76band77bof the lower side portion (45)76and the upper side portion (46)77being sewn together.

When assembling the airbag device10and mounting the airbag device10in a vehicle, firstly, the retainer24is placed inside the airbag30in such a way as to cause the bolts25of the retainer24to protrude from the attachment holes35. Next, the airbag30is folded, and the airbag30is wrapped in a predetermined unfolding preventing material in order that the airbag30does not become unfolded. The leading end portion60bside of the blocking tether60, which is outside the airbag30, is withdrawn from the unfolding preventing material.

Next, the airbag30is placed on the attachment plate11, while causing the bolts25of the retainer24to protrude from the attachment plate11, and extruding the leading end portion60bside of the blocking tether60to a back face side of the attachment plate11from the insertion hole14. Further, the main body portion18aof the inflator18is inserted into the insertion hole12from below, the bolts25of the retainer24are caused to penetrate the flange portion18c, and the nuts26are fastened to the bolts25. By so doing, the airbag30and the inflator18can be attached to the attachment plate11.

Next, the engagement pin62bof the actuator62is inserted into the engagement hole60cof the leading end portion60bof the blocking tether60. Also, the attachment plate11is covered with the airbag cover20, and the engagement legs (not shown) of the airbag cover20are caused to engage with the engagement holes13of the attachment plate11, whereby the airbag cover20is attached to the attachment plate11. By so doing, the airbag device10can be assembled. A state wherein the blocking tether60is caused to be held by the actuator62is an initial state of the airbag device10, and the blocking member50in this state blocks the exhaust hole38on the inner peripheral face30bside of the airbag30.

Also, the airbag device10can be mounted in the vehicle by the engagement legs16being caused to engage one each with the attachment portions5of the steering wheel main body1, which is fastened in advance to the steering shaft SS, and the airbag device10being attached to the steering wheel main body1. At this time, an operation signal line extending from the control device90is connected to the inflator18or the actuator62.

The driver's seat airbag device10of the embodiment is such that, firstly, a collision of the vehicle is detected by the collision detecting sensor91, and a signal is input into the control device90from the collision detecting sensor91, whereby the inflator18is caused to operate by the control device90. Because of this, an inflating gas G is discharged from the gas discharge port18bof the inflator18, and the airbag30inflates owing to the inflating gas G. The inflated airbag30pushes and opens the door portions21a,21aof the airbag cover20, protrudes from the airbag cover20, and covers an upper face RP side of the ring portion R, as shown by the two-dot chain lines inFIGS.1and2.

At this time, when the control device90determines, based on a signal output from the position detecting sensor92or the weight detecting sensor93, that the internal pressure of the airbag30is not to be reduced, the control device90does not cause the actuator62to operate. Because of this, the actuator62does not release the holding of the blocking tether60, meaning that the blocking member50maintains the state of blocking the exhaust hole38. That is, in a state wherein the exhaust hole38is blocked, the actuator62holds the leading end portion60bof the blocking tether60, the blocking member50is pulled by the blocking tether60, and the blocking member50covers and blocks the exhaust hole38owing to the first panel portion51and the second panel portion56, which are positioned one on the other, being pressed by the inflating gas G to the inner peripheral face30bside of the airbag30on the peripheral edge of the exhaust hole38(refer toFIGS.8A and10A). At this time, the through hole54of the first panel portion51, wherein the blocking member50itself is opened, is also blocked by a peripheral edge thereof being pressed to the inner peripheral face30bside of the airbag30, because of which it is difficult for the inflating gas G to flow into the tubular blocking member50from the through hole54. Also, even supposing that the inflating gas G flows into the blocking member50from the through hole54, the peripheral edge of the exhaust hole38is pressed against the second panel portion56, because of which a discharge of the inflating gas G from the exhaust hole38is restricted, and good airtightness when the exhaust hole38is blocked is secured.

Also, when the control device90determines, based on a signal output from the position detecting sensor92or the weight detecting sensor93, that the internal pressure of the airbag30is to be reduced when the inflator18operates, the control device90causes the actuator62to operate. Because of this, the actuator62releases the holding of the blocking tether60, and the blocking member50causes the exhaust hole38to be opened. That is, in a state wherein the exhaust hole38is opened, the holding of the blocking tether60by the actuator62is released, the blocking member50is subjected to the pressure of the inflating gas G without being pulled by the blocking tether60, and is fed out in such a way as to invert from the inner peripheral face30bside of the airbag30to the outer peripheral face30aside through the exhaust hole38and the communication hole52(refer toFIGS.8B,8C and10B). At this time, the through hole54is exposed on the outer peripheral face30aside of the airbag30before a whole region of the blocking member50from the peripheral edge of the exhaust hole38to the leading end region50bis fed out to the outer peripheral face30aside of the airbag30, because of which the inflating gas G is promptly discharged from the through hole54, whereby the internal pressure of the airbag30can be reduced.

Consequently, according to the airbag device10of the embodiment, the inflating gas G can be discharged promptly when the exhaust hole38is opened, while good airtightness of the airbag30is secured when the internal pressure adjustment exhaust hole38is blocked.

Also, the through hole54of the first panel portion51is disposed in a position in proximity to the communication hole52between the leading end region50band the communication hole52in the flattened first panel portion51. This means that when the blocking member50inverts when the inflating gas G is discharged, and the through hole54is exposed on the outer peripheral face30aside of the airbag30, the through hole54is more easily exposed on the outer peripheral face30aside of the airbag30by a degree equivalent to the proximity to the communication hole52communicating with the exhaust hole38, and the inflating gas G can be discharged still more promptly.

Also, in a state wherein the first panel portion51is flattened, the through hole54is of an elliptical form extended in the direction WD perpendicular to the disposition direction SD of the leading end region50band the communication hole52. When the inflating gas G is discharged from the through hole54, the blocking member50attempts to extend by causing the leading end region50bside to invert to the outer peripheral face30aside of the airbag30, as shown inFIGS.11A and11B, meaning that owing to this kind of configuration being employed, a tensile force TF acts in the disposition direction SD of the leading end region50band the communication hole52, the elliptical through hole54spreads into an approximately circular form in such a way as to increase an opening area, and the inflating gas G can be discharged efficiently. Of course, when the exhaust hole38is blocked, the through hole54is of an elliptical form with a small opening area, and is pressed to the inner peripheral face30bside of the airbag30, because of which airtightness of the inflating gas G in the airbag30is secured easily.

Also, in a state wherein the first panel portion51is flattened, the exhaust hole38is disposed in the region CA between the straight lines LF and LR, one on either side, that link the two edges53aand53bof the joint portion53, which is joined to the peripheral edge of the exhaust hole38, in the width direction WD along a direction perpendicular to the disposition direction SD of the leading end region50band the communication hole52, and the two edges51caand51cbof a region communicating with the blocking tether60in the leading end region50b, respectively. When the exhaust hole38is blocked, the blocking tether60is held by the actuator62, and the blocking member50is pulled by the blocking tether60from the peripheral edge of the exhaust hole38to the leading end region50b. At this time, the blocking member50is such that tension acts on two edges50cand50din the width direction WD, and tension is restricted in a vicinity of a central portion50fin the width direction, because of which the blocking member50, being subjected to the pressing force of the inflating gas G, attains a state wherein the central portion50fbetween the two edges50cand50din the width direction is slack, is pressed to the inner peripheral face30bside of the airbag30, and comes into close contact easily. This means that by the exhaust hole38being disposed in the central portion50fbetween the two edges50cand50din the width direction, leaking of inflating gas from the exhaust hole38is still further restricted, and airtightness when the exhaust hole38is blocked is secured easily.

Although the invention has been described with the driver's seat airbag device10as an example in the embodiment, the invention is not limited to this. That is, provided that a configuration is such that an exhaust hole for adjusting internal pressure of an airbag when inflation is completed is provided, the invention can also be applied to another airbag device, such as a passenger seat airbag device.