Airbag apparatus

An airbag apparatus includes an airbag with a first hole and a second hole; a tube vent disposed outside the airbag, wherein a proximal end portion of the tube vent is connected to a portion of the airbag, which is located around the first hole, so that communication is provided between an inside of the tube vent and an inside of the airbag through the first hole, and a distal end portion of the tube vent is inserted from the outside of the airbag into the inside of the airbag through the second hole; and a holding portion that holds the distal end portion of the tube vent from the inside of the airbag, wherein when the airbag is inflated and deployed, and the holding portion releases the tube vent, the distal end portion of the tube vent moves out of the second hole.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2008-015589 filed on Jan. 25, 2008 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to an airbag apparatus which is provided in a vehicle, and in which an airbag is deployed ahead of an occupant, for example, when a vehicle is rapidly decelerated.

2. Description of the Related Art

In an airbag of an airbag apparatus described in Japanese Patent Application Publication No. 2004-155420 (JP-A-2004-155420), a cylindrical tube is provided in a manner such that a distal end of the tube is positioned inside the airbag. Further, the distal end of the tube is held by, for example, a clamp. Even when the airbag is in an inflated and deployed state, the tube remains positioned inside the airbag. When the tube is held inside the airbag that is in the inflated and deployed state, the tube remains flattened by the pressure of gas in the airbag.

If the clamp releases the tube when the airbag is in the inflated and deployed state, the tube protrudes to the outside of the airbag due to the pressure in the airbag. Further, the tube is inflated by the pressure of the gas in the airbag. When the airbag apparatus is in this state, the gas in the airbag flows from a proximal end to the distal end of the tube, and the gas is discharged to the outside of the airbag. Thus, the pressure of the gas in the airbag is adjusted.

In the configuration described in the publication No. 2004-155420, when the distal end of the tube is held in the airbag, the tube is flattened by the pressure of the gas in the airbag. However, the gas in the airbag leaks through the tube when the airbag is in an initial inflated deployed state (that is, during a period from when the airbag starts to be inflated and deployed until when the airbag is sufficiently inflated and deployed). Therefore, the size of a gas generator that supplies the gas into the airbag, such as an inflator, needs to be increased to quickly inflate and deploy the airbag.

Also, in the configuration described in the publication No. 2004-155420, when the tube, which has been in the airbag, protrudes to the outside of the airbag, the tube is gradually reversed from the proximal end portion (that is, the tube is turned inside out so that a portion, which has been the inner periphery of the tube, is changed to the outer periphery of the tube, and a portion, which has been the outer periphery of the tube, is changed to the inner periphery of the tube). Therefore, when a timing, at which the tube is released in the airbag, is set, it is necessary to take into account a time required to reverse the tube. This makes it difficult to set the timing at which the tube is released.

SUMMARY OF THE INVENTION

The invention provides an airbag apparatus in which an airbag is quickly inflated and deployed without the need of increasing the size of a gas generator, and gas is quickly discharged from the airbag after the tube vent is released.

A first aspect of the invention relates to an airbag apparatus that includes an airbag which is inflated and deployed when gas is supplied into the airbag and a pressure in the airbag is increased, and in which a first hole and a second hole are formed, wherein each of the first hole and the second hole provides communication between an inside of the airbag and an outside of the airbag; a tube vent with a cylindrical shape disposed outside the airbag, wherein a proximal end portion of the tube vent is connected to a portion of the airbag, which is located around the first hole, so that communication is provided between an inside of the tube vent and the inside of the airbag through the first hole, and a distal end portion of the tube vent is inserted from the outside of the airbag into the inside of the airbag through the second hole; and a holding portion that holds the distal end portion of the tube vent from the inside of the airbag, wherein when the airbag is inflated and deployed, and the holding portion releases the tube vent, the distal end portion of the tube vent moves out of the second hole so that the tube vent protrudes to the outside of the airbag.

In the above-described aspect, when the gas is supplied into the airbag, the pressure in the airbag is increased, and accordingly, the airbag is inflated and deployed. The second hole is formed in the airbag. The tube vent is disposed outside the airbag, and the distal end portion of the tube vent is inserted through the second hole. Thus, the entire second hole or a large part of the second hole is closed. This restricts discharge of the gas through the second hole. Further, the proximal end portion of the tube vent is connected to the portion of the airbag, which is located around the first hole. Therefore, as the airbag is inflated and deployed, the tube vent is inflated by the pressure of the gas that flows into the tube vent through the first hole. As a result, the second hole is more effectively closed. Thus, it is possible to effectively restrict the discharge of the gas through the second hole, when the airbag is inflated and deployed.

When the airbag is inflated and deployed, and the holding portion releases the distal end portion of the tube vent, the distal end portion of the tube vent moves out of the airbag so that the tube vent protrudes to the outside of the airbag due to the pressure of the gas in the tube vent. As a result, the second hole, which has been closed by the tube vent, is opened, and the gas in the airbag is discharged to the outside of the airbag through the second hole.

Thus, in the airbag apparatus according to the above-described aspect, when the distal end portion of the tube vent is held, it is possible to restrict the discharge of the gas through the second hole during a period in which the airbag is inflated and deployed. Accordingly, it is possible to quickly inflate and deploy the airbag without the need of increasing the size of a gas generator that supplies gas into the airbag.

Further, during a period from when the holding portion releases the tube vent until when the second hole is opened, the distal end portion of the tube vent simply moves out of the second hole so that the tube vent protrudes to the outside of the airbag due to the pressure in the airbag. That is, the tube vent is not reversed. Therefore, it is possible to quickly open the second hole.

In the above-described aspect, the airbag may include a first side foundation cloth positioned in one side of the airbag in a width direction of a vehicle when the airbag is in an inflated and deployed state, a second side foundation cloth positioned in the other side of the airbag in the width direction of the vehicle when the airbag is in the inflated and deployed state, and an outer peripheral foundation cloth that connects an outer periphery of the first side foundation cloth to an outer periphery of the second side foundation cloth. The first hole, the second hole, and the tube vent may be provided in at least one of the first side foundation cloth and the second foundation cloth.

In the above-described aspect, the tube vent may be a dummy tube vent whose distal end is closed.

In the airbag apparatus according to the above-described aspect, a distal end of the tube vent may be open.

In the airbag apparatus according to the above-described aspect, the distal end of the tube vent is open. However, the distal end portion of the tube vent, which is held by the holding portion, is inserted into the airbag through the second hole. Therefore, even when then gas supplied into the airbag passes through the first hole and the tube vent, the gas is supplied into the airbag again. When the airbag apparatus is in this state, this suppresses leakage of the gas in the airbag to the outside of the airbag through the first hole and the tube vent.

When the airbag is inflated and deployed, and the holding portion releases the tube vent, the distal end portion of the tube vent moves out of the second hole so that the tube vent protrudes to the outside of the airbag due to the pressure of the gas. As a result, the second hole is opened, and the gas in the airbag is discharged to the outside of the airbag through the second hole. In addition, because the distal end of the tube vent is positioned outside the airbag, the gas in the airbag is discharged to the outside of the airbag through the first hole and the tube vent.

Thus, in the airbag apparatus according to the above-described aspect, the gas is discharged not only through the second hole but also through the first hole and the tube vent. Therefore, it is possible to quickly adjust the pressure in the airbag.

In the airbag apparatus according to the above-described aspect, an inner diameter of the second hole may be larger than an inner diameter of the first hole.

In the airbag apparatus according to the above-described aspect, the first hole and the second hole are formed in the airbag. The first hole corresponds to the proximal end portion of the tube vent. The distal end portion of the tube vent is inserted through the second hole. The inner diameter of the second hole is larger than the inner diameter of the first hole. Therefore, when the holding portion releases the distal end portion of the tube vent, and the tube vent protrudes to the outside of the airbag, the tube vent does not suffer great interference from the inner peripheral portion of the second hole, and the distal end portion of the tube vent smoothly moves out of the second hole.

In the airbag apparatus according to the above-described aspect, when the tube vent is inserted through the second hole, the second hole may be larger than an outer peripheral shape of a cross section of the tube vent taken along a radial direction of the second hole at a position corresponding to a position of the second hole.

In the airbag apparatus according to the above-described aspect, the distal end portion of the tube vent is inserted into the airbag through the second hole. When the tube vent is inserted into the airbag through the second hole, the second hole is larger than the outer peripheral shape of the cross section of the tube vent taken along the radial direction of the second hole at the position corresponding to the position of the second hole. Therefore, the tube vent does not suffer great interference from the inner peripheral portion of the second hole when the tube vent is inflated. Accordingly, the tube vent is sufficiently inflated.

Further, even when the tube vent is in the inflated state, the tube vent does not suffer unnecessary great interference from the inner peripheral portion of the second hole. Therefore, when the holding portion releases the distal end portion of the tube vent, and the tube vent protrudes to the outside of the airbag, the tube vent does not suffer great interference from the inner peripheral portion of the second hole, and the distal end portion of the tube vent smoothly moves out of the second hole.

In the above-described aspect, the first hole and the second hole may be formed in a manner such that there is a predetermined distance between the first hole and the second hole in a longitudinal direction of a vehicle when the airbag is in an inflated and deployed state.

In the above-described aspect, the first hole may be positioned closer to a rear of the vehicle than the second hole is.

In the airbag apparatus according to the above-described aspect, the second hole may be a long hole, and a longitudinal direction of the second hole may extend in the longitudinal direction of the vehicle; and the tube vent may be inserted through the second hole in a manner such that the tube vent is inclined with respect to a portion of a surface of the airbag, the portion of the surface being located around the second hole. The long hole may be any hole, as long as the length of the hole in the longitudinal direction is longer than the length of the hole in the height direction. The long hole may be a rectangular hole or an elliptical hole.

In the airbag apparatus according to the above-described aspect, the tube vent is inserted through the second hole in a manner such that in a manner such that the tube vent is inclined with respect to the portion of the surface of the airbag, the portion of the surface being located around the second hole. Therefore, when the distal end portion of the tube vent is held, the long second hole is substantially closed. Also, when the distal end portion of the tube vent is released, the distal end portion of the tube vent moves in the longitudinal direction of the second hole, and thus, the distal end portion of the tube vent smoothly moves out of the second hole.

In the airbag apparatus according to the above-described aspect, an outer diameter of the distal end portion of the tube vent, which is inserted through the second hole, may be smaller than an inner diameter of the second hole.

In the airbag apparatus according to the above-described aspect, even when the tube vent is in the inflated state, the tube vent does not suffer unnecessarily great interference from the inner peripheral portion of the second hole. Therefore, when the holding portion releases the distal end portion of the tube vent, and the tube vent protrudes to the outside of the airbag, the tube vent does not suffer great interference from the inner peripheral portion of the second hole, and the distal end portion of the tube vent smoothly moves out of the second hole.

In the airbag apparatus according to the above-described aspect, the tube vent may be tapered, and the tube vent may become narrower toward the distal end portion.

In the airbag apparatus according to the above-described aspect, it is possible to greatly reduce the interference from the inner peripheral portion of the second hole when the distal end portion of the tube vent moves out of the second hole. Thus, the tube vent even more smoothly protrudes.

In the airbag apparatus according to the above-described aspect, the holding portion may include a tether, and a tether holding device that holds and releases the tether; and the distal end portion of the tube vent may be connected to the tether holding device by the tether.

In the airbag apparatus according to the above-described aspect, it is possible to hold and release the tether based on a sensor signal input to the tether holding device.

DETAILED DESCRIPTION OF EMBODIMENTS

[Configuration in first embodiment]FIG. 1is a perspective view showing a main portion of an airbag apparatus10according to a first embodiment of the invention.FIG. 5is a perspective view showing the airbag apparatus10seen from the rear side thereof. InFIG. 1, an airbag30described later is deployed, and inFIG. 5, the airbag30is folded.

As shown inFIG. 1andFIG. 5, the airbag apparatus10includes a base plate12. As shown inFIG. 2, when the airbag apparatus10is a passenger-side airbag in a vehicle14, the base plate12is fixed to a vehicle body structure member such as a reinforcement on the rear surface side of an instrument panel16of the vehicle14. Also, although detailed illustration is omitted, when the airbag apparatus10is a driver-side airbag in the vehicle14, the base plate12is disposed inside a rim of a steering wheel, and fixed to, for example, a spoke of the steering wheel.

The base plate12includes a bottom wall20that is substantially rectangular in a planar view. A peripheral wall22extends upward (downward inFIG. 5) from an outer peripheral portion of the bottom wall20. The airbag30in a folded state is provided in the base plate12. An open end of the airbag30is fixed to the bottom wall20at a position inside the peripheral wall22using, for example, a bracket. An inflator40is provided in the base plate12. A body portion of the inflator40has a substantially disc shape, or a substantially columnar shape whose axial length is relatively short.

A flange portion42is formed in an axial intermediate portion of the body portion of the inflator40as shown inFIG. 2toFIG. 4(the flange portion42is omitted inFIG. 5). Further, a portion of the body portion of the inflator40, which is located below the flange portion42(i.e., a portion of the body portion, which is located above the flange portion42inFIG. 5), is inserted through a circular hole44formed in the bottom wall20. Thus, the portion of the inflator40is inserted through the circular hole44, and the flange portion42contacts the upper surface of the bottom wall20. The inflator40is fixed to the bottom wall20in a manner such that sealing is provided between the circular hole44and the inflator40.

The inflator40, which is thus attached to the base plate12, is positioned inside the open end portion of the airbag30that is in the folded state. When the inflator40is operated, the inflator40generates gas instantaneously, and further, the generated gas is discharged to the outside of the inflator40from a portion of the inflator40, which is located above the bottom wall20(i.e., a portion of the inflator40, which is located below the bottom wall20inFIG. 5). The airbag30is inflated by the pressure of the gas thus discharged from the inflator40.

As shown inFIG. 2, an airbag door50, which faces the airbag apparatus10, is formed in the instrument panel16of the vehicle14. The airbag door50is rectangular in a planar view. The outer peripheral shape of the airbag door50is larger than the outer peripheral shape of the peripheral wall22(i.e., the outer peripheral shape of the base plate12). A hinge portion52is formed at a boundary between an upper portion of the airbag door50and a portion of the instrument panel16other than the airbag door50. The hinge portion52of the instrument panel16is thinner than the portion of the instrument panel16other than the hinge portion52. Thus, the mechanical strength of the hinge portion52is lower than that of the portion of the instrument panel16other than the hinge portion52.

A breaking portion54is formed at a boundary between the right, left and lower portions of the airbag door50, and a portion of the instrument panel16other than the airbag door50. The breaking portion54of the instrument panel16is even thinner than the hinge portion52of the instrument panel16. Thus, the mechanical strength of the breaking portion54is even lower than that of the hinge portion52.

When the airbag30is inflated by the pressure of the gas supplied from the inflator40as described above, and the inflated airbag30presses the airbag door50from the rear surface side of the instrument panel16, the instrument panel16is broken at the breaking portion54, and further, the airbag door50pivots around the hinge portion52. Thus, the instrument panel16is opened at a position at which the airbag door50is provided, and accordingly, the inflated airbag30is deployed toward a cabin of the vehicle14.

As shown inFIG. 1, the airbag30includes a bag body60. The bag body60includes a side foundation cloth62whose outer surface substantially faces toward one side in a width direction of the vehicle14when the airbag30is in the inflated and deployed state, and a side foundation cloth64whose outer surface substantially faces toward the other side in the width direction of the vehicle14when the airbag30is in the inflated and deployed state. The outer periphery of the side foundation cloth62and the outer periphery of the side foundation cloth64are connected to each other by an outer peripheral foundation cloth66, except for portions of the outer peripheries of the side foundation cloths62and64at the open end of the airbag30. Thus, the entire bag body60has a bag shape.

As shown inFIG. 1andFIG. 3, a first hole72is formed in the side foundation cloth62. A tube vent74with a cylindrical shape, which corresponds to the first hole72, is provided in the side foundation cloth62. In the embodiment, both ends of the tube vent74are open. Further, when the airbag30is in the deployed state, the tube vent74gradually becomes narrower from a proximal end portion toward a distal end portion. The proximal end portion of the tube vent74(i.e., the open end at the proximal end side) is connected to the peripheral edge of the first hole72. Communication is provided between the tube vent74and the inside of the bag body60through the first hole72.

As shown inFIG. 1andFIG. 3, a second hole76is formed on a side of the first hole72in the side foundation cloth62(particularly in the embodiment, the second hole76is positioned ahead of the first hole72when the airbag30is in the inflated and deployed state). The second hole76is positioned at a predetermined distance from the first hole72. A portion of the tube vent74on the distal end side of the proximal end portion is positioned outside the bag body60. However, the distal end portion of the tube vent74is inserted into the bag body60through the second hole76. The outer diameter of the distal end portion of the tube vent74with a tapered shape, which is inserted through the second hole76, is smaller than the inner diameter of the second hole76. Also, a proximal end portion of a tether78is fixed to the distal end portion of the tube vent74. The tether78functions as a connecting member, and a holding portion. As shown inFIG. 6, a distal end portion of the tether78extends to the outside of the base plate12through the inside of the bag body60and a small hole80formed in the bottom wall20of the base plate12.

In addition, as shown inFIG. 1andFIG. 3, a first hole82is formed in the side foundation cloth64. A tube vent84with a cylindrical shape, which corresponds to the first hole82, is provided in the side foundation cloth64. In the embodiment, both ends of the tube vent84are open, as well as the tube vent74. Further, the tube vent84gradually becomes narrower from a proximal end portion to a distal end portion when the airbag30is in the deployed state. The proximal end portion of the tube vent84(i.e., the open end at the proximal end side) is connected to the peripheral edge of the first hole82. Communication is provided between the tube vent84and the inside of the bag body60through the first hole82.

Further, a second hole86is formed on a side of the first hole82(particularly in the embodiment, the second hole86is positioned ahead of the first hole82when the airbag30is in the inflated and deployed state), in the side foundation cloth64. The second hole86is positioned at the predetermined distance from the first hole82. A portion of the tube vent84on the distal end side of the proximal end portion is positioned outside the bag body60. However, the distal end portion of the tube vent84is inserted into the bag body60through the second hole86. The outer diameter of the distal end portion of the tube vent84with a tapered shape, which is inserted through the second hole86, is smaller than the inner diameter of the second hole86. Also, a proximal end portion of a tether88is fixed to the distal end portion of the tube vent84. The tether88functions as the connecting member, and the holding portion. A distal end portion of the tether88extends through the inside of the bag body60, and extends through the small hole80together with the tether78. Thus, the distal end portion of the tether88extends to the outside of the base plate12.

As shown inFIG. 5, a tether holding device100, which functions as the holding portion, is provided on the rear surface side of the base plate12. As shown inFIG. 6, the tether holding device100includes a micro gas generator122. The micro gas generator122includes a cylinder124. The axial direction of the cylinder124extends in parallel with the outer surface of the bottom wall20. A piston (not shown) is housed in the cylinder124in a manner such that the piston slides in the axial direction of the cylinder124. A proximal end portion of a rod126is integrally connected to one end of the piston in the axial direction of the cylinder124. A distal end portion of the rod126extends to the outside of the cylinder124. A slider128is connected to the distal end of the rod126. The slider128includes a connecting piece130.

The connecting piece130has a plate shape. The thickness direction of the connecting piece130extends in the axial direction of the cylinder124. The longitudinal direction of the connecting piece130extends in substantially parallel with the outer surface of the bottom wall20. The distal end of the rod126is integrally connected to one surface of the connecting piece130in the thickness direction thereof at one end side of the connecting piece130in the longitudinal direction thereof. A holding piece132is formed at one end of the connecting piece130in the width direction thereof (i.e., the end close to the bottom wall20) at the other end side of the connecting piece130in the longitudinal direction thereof. The holding piece132has a plate shape. Each of the longitudinal direction and the width direction of the holding piece132extends in substantially parallel with the outer surface of the bottom wall20. A proximal end portion of the holding piece132in the longitudinal direction thereof is connected to the connecting piece130. The direction toward the distal end portion of the holding piece132in the longitudinal direction thereof is opposite to the direction toward the distal end portion of the rod126in the longitudinal direction thereof.

The holding piece132extends above the small hole80formed in the bottom wall20of the base plate12. The holding piece132is inserted through a loop134with a ring shape formed at the distal end portion of the tether78and a loop136with a ring shape formed at the distal end portion of the tether88. Because the holding piece132is inserted through the loops134and136, the distal end portions of the tethers78and88are restricted from moving toward the inside of the base plate12through the small hole80.

Also, a gas-generating agent and an ignition device are housed in the cylinder124(more specifically, in the cylinder124, the gas-generating agent and the ignition device are disposed at a side opposite to a side where the rod126of the piston is disposed). When the gas-generating agent is burned, gas is instantaneously generated. The ignition device ignites the gas-generating agent based on an ignition signal from a control portion such as an airbag ECU (not shown). When the gas is generated in the cylinder124by burning the gas-generating agent, and a pressure in the cylinder124is increased, the piston slides in the cylinder124. When the piston thus slides, the rod126slides, and further, the slider128moves away from the cylinder124. When the slider128thus moves, and accordingly, the holding piece132moves out of the loops134and136, the holding piece132releases the tethers78and88. As a result, the distal end portions of the tethers78and88move to the inside of the base plate12through the small hole80.

The tether holding device100further includes a fixation member142. The fixation member142includes a base portion144with a plate shape. A generator holding piece146extends from the base portion144. The generator holding piece146is curved along the outer peripheral shape of the cylinder124in a manner such that the generator holding piece146is open toward the bottom wall20. The cylinder124is disposed inside the generator holding piece146. When the fixation member142is screwed to the bottom wall20, the cylinder124is held by the generator holding piece146and the bottom wall20.

A slide guide148extends from a position in the base portion144, which faces the distal end portion of the holding piece132. The slide guide148extends in the longitudinal direction of the holding piece132. The slide guide148is formed so that there is a gap between a distal end portion of the slide guide148and the outer surface of the bottom wall20, and the gap is slightly larger than the thickness of the holding piece132. The holding piece132is inserted between the slide guide148and the bottom wall20. A rectangular hole150, which faces the small hole80, is formed in the slide guide148. The holding piece132is inserted through the loops134and136, and portions of the loops134and136, which are located closer to the slide guide148than to the holding piece132, are inserted into the hole150.

[Advantageous effects obtained in the first embodiment] Next, advantageous effects obtained in the first embodiment will be described.

In the airbag apparatus10, when a vehicle-state detection sensor, such as an acceleration sensor, detects that the vehicle is rapidly decelerated, and a detection signal output from the vehicle-state detection sensor is input to the control portion such as the airbag ECU, an ignition device (not shown) provided in the inflator40is operated. When the ignition device of the inflator40is operated, the gas-generating agent in the inflator40is burned by the ignition device. When the gas-generating agent is burned, a large amount of gas is instantaneously generated.

The gas thus generated in the inflator40is discharged to the outside of the inflator40from the portion of the inflator40, which is located above the bottom wall20. Because the inflator40is provided inside the open end portion of the airbag30, the gas discharged from the inflator40is supplied into the airbag30. Because the gas is supplied into the airbag30, the airbag30is inflated. The inflated airbag30presses the airbag door50from the rear side of the instrument panel16. When the airbag30presses the airbag door50, the instrument panel16is broken at the breaking portion54, and the airbag door50pivots around the hinge portion52. Thus, a rectangular hole is formed in the instrument panel16, and accordingly, the inflated airbag30is deployed ahead of the seat that faces the airbag apparatus10, in the cabin of the vehicle14, as shown inFIG. 3.

If the airbag30is in the deployed state in the cabin of the vehicle14, and an occupant seated on the seat that faces the airbag apparatus10is about to move toward the front of the vehicle14due to inertia that occurs when the vehicle is rapidly decelerated, the deployed airbag30receives the body of the occupant.

When the airbag30is thus inflated and deployed, the gas is supplied into the tube vents74and84through the first holes72and82, respectively. As a result, the tube vents74and84are inflated. The distal end portion of the tube vent74is inserted into the bag body60through the second hole76, and the distal end portion of the tube vent84is inserted into the bag body60through the second hole86. Therefore, when the tube vents74and84are inflated, the tube vents74and84are about to move out of the second holes76and86, respectively, due to tensional forces of the tube vents74and84.

However, for example, in the case where it is determined that the physical size of the occupant seated on the seat is not small based on a signal from an occupant physical size detection sensor such as a load sensor provided in the seat, the micro gas generator122is not operated. Therefore, the holding piece132remains inserted through the loop134of the tether78and the loop136of the tether88. Accordingly, the distal end portion of the tube vent74, which is connected to the proximal end portion of the tether78, cannot move out of the second hole76, and the distal end portion of the tube vent84, which is connected to the proximal end portion of the tether88, cannot move out of the second hole86. Therefore, when the airbag apparatus10is in this state, even if the gas in the bag body60flows through the first holes72and82, and further flows through the tube vents74and84, the gas returns into the airbag30. This suppresses leakage of the gas in the airbag30to the outside of the airbag30through the tube vents74and84.

Also, the second holes76and86are formed in the bag body60. When the tube vents74and84are inflated, large parts of the second holes76and86are closed by the tube vents74and84, respectively. Therefore, when the airbag30is in the inflated and deployed state, gas leakage through the second holes76and86is effectively suppressed. Accordingly, when the airbag30is in the inflated and deployed state, the pressure in the airbag30is maintained, and the body of the relatively large occupant is effectively received.

In contrast, for example, in the case where it is determined that the physical size of the occupant seated on the seat is small based on the signal from the occupant physical size detection sensor such as the load sensor provided in the seat, when the control portion such as the airbag ECU outputs the ignition signal to the ignition device of the inflator40, the control portion also outputs the ignition signal to the ignition device of the micro gas generator122. When the ignition device of the micro gas generator122is operated, the gas-generating agent in the cylinder124is burned, and the gas is generated in the cylinder124. As a result, the pressure in the cylinder124is increased, and accordingly, the piston slides in the cylinder124.

When the piston slides, and accordingly, the rod126slides, the slider128moves away from the cylinder124. As a result, the holding piece132slides, and moves out of the loops134and136. When the holding piece132thus moves out of the loops134and136, the holding piece132releases the tethers78and88. When the airbag30is inflated and deployed, the gas is supplied into the tube vents74and84through the first holes72and82, and accordingly, the tube vents74and84are about to be straightened.

The tube vents74and84, which are about to be straightened, pull the tethers78and88. When the airbag apparatus10is in this state, the holding piece132does not hold the tethers78and88, and therefore, the distal end portions of the tethers78and88can pass through the small hole80. Therefore, the tube vents74and84are straightened while the tube vents74and84pull the tethers78and88, respectively so that the tethers78and88pass through the small hole80. Further, as shown inFIG. 4, the tube vent74moves out of the second hole76, and the tube vent84moves out of the second hole86. When the airbag apparatus10is in this state, communication is provided between the inside and outside of the airbag30through the first holes72and82and the tube vents74and84. Therefore, the gas in the airbag30is discharged to the outside of the airbag30through the first holes72and82, and the tube vents74and84.

Also, as described above, the second holes76and86, which have been closed by the tube vents74and84, respectively, are opened when the tube vents74and84are straightened, and move out of the second holes76and86, respectively. Therefore, the gas in the airbag30is discharged also through the second holes76and86. Thus, when the relatively small occupant is received by the airbag30, the tension of the airbag30is low.

As described above, in the airbag apparatus10, when the holding piece132is inserted through the loops134and136, and therefore, the distal end portions of the tube vents74and84cannot move out of the second holes76and86, respectively, it is possible to suppress the leakage of the gas to the outside of the airbag30through the first holes72and82and the tube vents74and84. It is also possible to effectively suppress the gas leakage through the second holes76and86closed by the tube vents74and84, respectively. Thus, it is possible to quickly inflate and deploy the airbag30without the need of increasing the size of the inflator40.

Further, when the holding piece132does not hold the proximal end portions of the tethers78and88, and the tube vents74and84are straightened by the pressure in the airbag30, and accordingly, the tube vents74and84move out of the second holes76and86, respectively, communication is provided between the inside and outside of the airbag30through openings at distal ends of the tube vents74and84connected to the peripheral edges of the first holes72and82, and through the second holes76and86, without the need of reversing the tube vents74and84(i.e., without the need of turning the tube vents74and84inside out). Thus, it is possible to quickly reduce (adjust) the pressure in the airbag30. The outer diameter of the distal end portion of each of the tube vents74and84, which are inserted through the second holes76and86, is smaller than the inner diameter of each of the second holes76and86. Therefore, even when the tube vents74and84are in the inflated stated, the tube vents74and84do not suffer unnecessarily great interference from the inner peripheral portions of the second holes76and86. Accordingly, when the holding pieces132releases the distal end portions of the tube vents74and84, and the tube vents74and84protrude to the outside of the airbag30, the tube vents74and84do not suffer great interference from the inner peripheral portions of the second holes76and86, and the distal end portions of the tube vents74and84smoothly move out of the second holes76and86. Also, because the distal end portions of the tube vents74and84are tapered, it is possible to greatly reduce the interference from the inner peripheral portions of the second holes76and86when the distal end portions of the tube vents74and84move out of the second holes76and86. Thus, the tube vents74and84even more smoothly protrude to the outside of the airbag30.

In the embodiment, the first hole72and the second hole76are formed, and the tube vent74is provided in the side foundation cloth62, and the first hole82and the second hole86are formed, and the tube vent84is provided in the side foundation cloth64. However, the configuration may be such that the first hole, the second hole, and the tube vent are provided only one of the side foundation cloths. That is, the configuration may be such that the first hole72and the second hole76are formed, and the tube vent74is provided in the side foundation cloth62, while the first hole82and the second hole86are not formed, and the tube vent84is not provided in the side foundation cloth64. Also, the configuration may be such that the first hole82and the second hole86are formed, and the tube vent84is provided in the side foundation cloth64, while the first hole72and the second hole76are not formed, and the tube vent74is not provided in the side foundation cloth62.

Also, in the embodiment, the distal end of each of the tube vent74and the tube vent84is open. After the distal end portions of the tube vents74and84move out of the second holes76and86, respectively, communication is provided between the inside and outside of the airbag30through the first holes72and82and the tube vents74and84. However, the configuration may be such that the distal end of each of the tube vent74and the tube vent84is closed. In this configuration, even when the distal end portions of the tube vents74and84move out of the second holes76and86, respectively, communication is not provided between the inside and outside of the airbag30through the first holes72and82and the tube vents74and84. Communication is provided between the inside and outside of the airbag30only through the second hole76and the second hole86.

Further, in the embodiment, when the holding piece132is inserted through the loops134and136of the tethers78and88, the holding piece132holds the distal end portions of the tethers78and88. When the holding piece132moves out of the loops134and136, the holding piece132releases the distal end portions of the tethers78and88. However, the configuration for holding and releasing the distal end portions of the tethers78and88is not limited to the configuration in the embodiment. For example, the configuration may be such that the slide guide148holds the distal end portions of the tethers78and88. In this configuration, when the micro gas generator122is operated, a cutter slides and cuts the tethers78and88, and thus, the slide guide148releases the tethers78and88.

[Second embodiment] Next, a second embodiment of the invention will be described. In the description of the second embodiment, basically, the same and corresponding portions as those in the first embodiment are denoted by the same reference numerals, and the detailed description thereof will be omitted.

FIG. 7is a plan view showing a configuration of an airbag apparatus180according to the second embodiment. As shown inFIG. 7, the airbag apparatus180does not include the airbag30. The airbag apparatus180includes an airbag182instead of the airbag30. The airbag182includes the bag body60and the tube vents74and84, as well as the airbag30in the first embodiment. However, the second hole76is not formed in the side foundation cloth62of the bag body60of the airbag182. Instead of the second hole76, a second hole184is formed in the side foundation cloth62of the bag body60of the airbag182. Also, the second hole86is not formed in the side foundation cloth64of the bag body60of the airbag182. Instead of the second hole86, a second hole186is formed in the side foundation cloth64of the bag body60of the airbag182.

As shown inFIG. 9, each of the second holes184and186is a long hole (or an elliptical hole). The longitudinal direction of each of the second holes184and186substantially extends in the longitudinal direction of the vehicle14(inFIG. 9, only the second hole184is shown, and the second hole186is omitted). The inner peripheral length of each of the second holes184and186is longer than the inner peripheral length of each of the first holes72and82(inFIG. 9, only the first hole72is shown, and the first hole82is omitted). The length of the minor axis of each of the second holes184and186(i.e., the length shown by the arrow B inFIG. 9) is longer than the inner diameter of each of the first holes72and82(i.e., the length shown by the arrow C inFIG. 9). The length of the minor axis of each of the second holes184and186is the length of each of the second holes184and186in a direction substantially orthogonal to the direction of the major axis of each of the second holes184and186(i.e., the direction shown by the arrow A inFIG. 9). The length of the minor axis of the second hole184is longer than the outer diameter of the tube vent74at a position corresponding to a position of the second hole184. The length of the minor axis of the second hole186is longer than the outer diameter of the tube vent84at a position corresponding to a position of the second hole186(inFIG. 9, only the tube vent74is shown, and the tube vent84is omitted).

Further, as shown inFIG. 7, in the airbag apparatus180, the tube vent74is inserted through the second hole184in a manner such that the tube vent74is inclined with respect to a portion of the surface of the side foundation cloth62of the bag body60, the portion of the surface being located around the second hole184. The tube vent84is inserted through the second hole186in a manner such that the tube vent84is inclined with respect to a portion of the surface of the side foundation cloth64of the bag body60, the portion of the surface being located around the second hole186. That is, the tube vents74and84are inserted through the second holes184and186, respectively, in a manner such that the tube vents74and84are inclined with respect to the second holes184and186, respectively. In the airbag apparatus180, the inner peripheral length of the second hole184is longer than the outer peripheral length of the cross section of the tube vent74taken along the direction orthogonal to the direction that extends from the outside of the airbag30to the inside of the airbag30through the second hole184, at the position corresponding to the position of the second hole184. The inner peripheral length of the second hole186is longer than the outer peripheral length of the cross section of the tube vent84taken along the direction orthogonal to the direction that extends from the outside of the airbag30to the inside of the airbag30through the second hole186, at the position corresponding to the position of the second hole186.

As described above, when the distal end portions of the tube vents74and84are inserted through the long second holes184and186, and the distal end portions of the tube vents74are held, the long second holes184and186are substantially closed by the tube vents74and84that are inserted through the second holes184and186, respectively, in a manner such that the tube vents74and84are inclined with respect to the second holes184and186, respectively. Thus, it is possible to suppress the gas leakage from the bag body60. In the airbag apparatus180in which the diameter and the inner peripheral length (that is, the inner peripheral shape) of each of the second holes184and186is set, each of the second holes184and186is larger than each of the first holes72and82. Further, the inner peripheral shape of each of the second holes184and186is larger than the outer peripheral shape of each of the tube vents74and84. Therefore, when the holding piece132releases the distal end portions of the tethers78and88, and the tube vents74and84are about to be straightened, and about to move out of the second holes184and186, respectively, the tube vents74and84do not suffer great interference from the inner peripheral portions of the second holes184and186. Thus, as shown inFIG. 8, the tube vents74and84smoothly move out of the second holes184and186, respectively, to the outside of the bag body60, and accordingly, the tube vents74and84are straightened. Also, when the distal end portions of the tube vents74and84are released, and the tube vents74and84move out of the second holes184and186, respectively, the distal end portions of the tube vents74and84move in the longitudinal direction of the long second holes184, and186. Thus, the tube vents74and84more smoothly move out of the second holes184and186.

In the embodiment, each of the second holes184and186is a long hole. However, each of the second holes184and186may be a circular hole that is larger than the outer peripheral shape of each of the first holes72and82, and the outer peripheral shape of each of the tube vents74and84.