JP2011079450A - Airbag device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag device secured in the joining strength of a first bag and a second bag in relation to a load when an occupant is restrained by the first bag and the second bag. <P>SOLUTION: This airbag device 10 for a front passenger seat includes an airbag 20 formed by joining the main bag 26 for restraining the upper body U of the occupant P from a vehicle front side while being inflated and deployed and a sub-bag 28 having a smaller capacity than that in the main bag 26 to restrain the knees K of the occupant P from the vehicle front side while being inflated and deployed in a joining part J. A tension relaxing structure 45 including a folded part 46 provided so that foundation cloth 30 may be deployed in the vertical direction when the tension of the vertical direction of a prescribed value or more is applied to the foundation cloth 30 is set between a portion 26H with which the head part H of the occupant P is in contact with the rear surface of the foundation cloth 30 constituting the main bag 26 and the joining part J. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an airbag apparatus including a first bag that restrains an upper body of an occupant and a second bag that restrains a knee.

  An airbag device is known in which an airbag for restraining a knee is connected to an airbag for restraining the upper body of an occupant (for example, see Patent Document 1). There is also known an airbag device that simultaneously inflates and deploys an airbag for restraining the upper body of an occupant and an airbag for restraining a knee by gas supply from a common pressure accumulator (for example, Patent Document 2).

Japanese Utility Model Publication No.7-17662 JP-A-51-23917

  By the way, when the airbag for restraining the upper body and the airbag for restraining the knee are integrally configured, the upper body is restrained by the input from the head of the occupant and the input from the knee. The load in the direction of pulling up and down the airbag for restraining the knee and the airbag for restraining the knee acts.

  An object of the present invention is to obtain an airbag device in which the bonding strength of the first and second bags against the load when the occupant is restrained by the first and second bags is secured.

  The airbag device according to the first aspect of the present invention includes a first bag that restrains an upper body of a vehicle occupant from the front side in the vehicle front-rear direction by being inflated and deployed upon receiving gas supply, and the first bag. And a second bag that is joined to the first bag, is inflated and deployed by receiving a gas supply, and restrains the occupant's knee from the front side in the vehicle front-rear direction, and the first bag. When a vertical tension of a predetermined value or more acts on the base fabric between a portion where the head of the occupant contacts a portion of the portion of the base fabric that faces the occupant and a joint portion of the second bag, A tension relief structure provided so that the base fabric is developed in the vertical direction.

  In the airbag device according to claim 1, for example, when gas is supplied at the time of a frontal collision of the vehicle, the first bag is deployed in front of the vehicle with respect to the occupant's upper body, and the second bag is against the occupant's knee. It is deployed in front of the vehicle. Thus, the deployed first bag restrains the occupant's upper body, and the deployed second bag restrains the occupant's knee. At this time, the first bag is pulled upward in the vehicle at the contact (restraint) portion with the head on the occupant side surface (rear surface), and the second bag is in contact (restraint) with the knee on the occupant side surface (rear surface). By being pulled downward in the vehicle at the portion, a load (tension) in the direction of pulling up and down acts on the first and second airbags.

  Here, in the airbag device, a predetermined value is provided between the contact portion of the head portion of the base fabric of the first bag and the joint portion of the second bag due to a load in a direction in which the first and second airbags are pulled up and down. When the above tension acts, the base fabric is developed in the vertical direction in the tension relaxation structure. Thereby, the tension | tensile_strength of the direction which pulls apart a 1st, 2nd airbag up and down is relieve | moderated (reduced), and it is suppressed that a big load (stress) acts on the junctional part of a 1st bag and a 2nd bag.

  Thus, in the airbag device according to the first aspect, the bonding strength of the first and second bags against the load when the occupant is restrained by the first and second bags is ensured.

  The airbag device according to a second aspect of the present invention is the airbag device according to the first aspect, wherein the tension relief structure is a portion where the head portion of the occupant contacts a portion of the base fabric facing the occupant side. The folding part formed so as to be able to expand in the vertical direction between the joint part with the second bag and the folded state of the folding part are maintained by sewing, and acts on the part of the base fabric including the folding part. And a tear seam that is broken by a vertical tension equal to or greater than a predetermined value.

  In the airbag device according to claim 2, when a tension of a predetermined value or more in a direction in which the first and second airbags are pulled up and down acts, the tear seam is broken and the folded portion formed on the base fabric of the first bag The sewing (restraint) state is released, and the base fabric is unfolded up and down. As a result, the tension in the direction of separating the first and second airbags up and down is relaxed (reduced), and it is effectively suppressed that a large load (stress) acts on the joint portion between the first bag and the second bag. Is done.

  The airbag apparatus according to a third aspect of the present invention is the airbag apparatus according to the first or second aspect, wherein the tension relaxation structure is a portion where the head of the occupant contacts the base fabric of the first bag. It is provided closer to the joint portion of the base fabric with the second bag.

  In the airbag device according to the third aspect, the tension relaxation structure (folding portion and tear seam) is arranged closer to the joint portion side with the second bag than the load input portion from the occupant in the first bag. For this reason, in this airbag apparatus, it is much more effective that a large load (stress) acts on the joining site | part of a 1st bag and a 2nd bag because a base fabric is expand | deployed up and down by a tension relaxation structure. It is suppressed.

  The airbag device according to a fourth aspect of the present invention is the airbag device according to any one of the first to third aspects, wherein the second bag has a texture seal structure that suppresses gas leakage from the texture. The internal pressure in the deployment completion state is set to be higher than the internal pressure in the deployment completion state of the first bag.

  5. The airbag device according to claim 4, wherein the base fabric constituting the second bag deployed at an internal pressure higher than that of the first bag has a textured seal structure, so that the base fabric of the second bag is caused by the high internal pressure. It is possible to effectively suppress gas leakage from the weave. The second bag made of the base fabric is joined to the first bag by sewing or the like, but the joint is effectively protected by the above-described tension relaxation structure.

  As described above, the airbag apparatus according to the present invention has an excellent effect of ensuring the bonding strength of the first and second bags against the load when the occupant is restrained by the first and second bags.

It is a sectional side view which shows the deployment state of the airbag in the airbag apparatus which concerns on embodiment of this invention. It is side sectional drawing which expands and shows the airbag which comprises the airbag apparatus which concerns on embodiment of this invention. It is the partially cutaway rear view which shows the deployment state of the airbag in the airbag apparatus which concerns on embodiment of this invention. It is a sectional side view which shows the 1st modification of the energy absorption which comprises the airbag apparatus which concerns on embodiment of this invention. It is a sectional side view which shows the 2nd modification of the energy absorption which comprises the airbag apparatus which concerns on embodiment of this invention.

  A passenger seat airbag apparatus 10 as an airbag apparatus according to an embodiment of the present invention will be described with reference to FIGS. In addition, arrow FR, arrow UP, and arrow W appropriately described in each figure respectively indicate the vehicle V to which the passenger seat airbag device 10 is applied, the vehicle front direction (traveling direction), the upward direction, and the vehicle width direction of the passenger seat 12. Is shown. Further, in the following description, when the shape of the airbag 20 (its constituent part) is described, the shape in the inflated and deployed state is referred to unless otherwise specified.

  FIG. 1 is a schematic side cross-sectional view of a front portion in a passenger compartment C of an automobile V in an operating state of a passenger seat airbag device 10. As shown in this figure, a passenger seat 12 as a vehicle seat is disposed in the front part of the passenger compartment C. The passenger seat 12 includes a seat cushion 12A for the occupant P to sit forward and a seat back 12B that supports the seated occupant P of the seat cushion 12A from the rear of the vehicle.

  A windshield glass 14 that defines the front end of the vehicle in the passenger compartment C is disposed in front of the passenger seat 12. An instrument panel 16 is provided below the vehicle with respect to the windshield glass 14. The instrument panel 16 protrudes toward the passenger seat 12, and the seated occupant P of the passenger seat 12 puts his feet under the instrument panel 16. Therefore, the seated occupant P of the passenger seat 12 is configured to bring the knee K close to the instrument panel 16.

  The passenger seat airbag apparatus 10 includes an airbag module 18 disposed in the instrument panel 16. The airbag module 18 includes an airbag 20 described later, an inflator 22 for supplying gas to the airbag 20, and an airbag case 24 holding (partially containing) the airbag 20 and the inflator 22. It is configured. The airbag module 18 is held by an attachment portion 16 </ b> A provided on the instrument panel 16 in the airbag case 24.

  In this embodiment, as shown in FIG. 1, the airbag 20 includes a main bag 26 as a first bag for protecting the upper body U including the head H of the seated occupant P, and a second bag for protecting the knee K. As a sub-bag 28. For this reason, in the passenger seat airbag device 10, the airbag module 18 is provided in the vicinity of the rearmost portion of the vehicle in the instrument panel 16 so as to face the vehicle rearward and upward. Specifically, in the airbag device 10 for the passenger seat, the airbag case 24 of the airbag module 18 is held by the mounting portion 16A of the instrument panel 16 in a posture that opens toward the rear of the vehicle and upward of the vehicle. Yes.

  The airbag case 24 holds (partially accommodates) the airbag 20 in a folded state as shown by a two-dot chain line in FIG. The airbag 20 is kept in a folded state by being wrapped in a holding sheet or the like (not shown). The inflator 22 is fixedly held by the airbag case 24 in a state in which a part including the gas ejection port 22 </ b> A is inserted into the airbag 20. In this embodiment, the inflator 22 is a so-called disk-type inflator, and a sufficient gas capacity is ensured for the airbag 20 having the main bag 26 and the subbag 28 as described above.

  The main bag 26 of the airbag 20 is inflated and deployed between the windshield glass 14 and the instrument panel 16 and the upper body U of the seated occupant P, and restrains the relative movement of the upper body U forward of the vehicle. It has become. In this embodiment, a vent hole 25 for adjusting internal pressure is formed in the main bag 26. The sub bag 28 is inflated and deployed between the instrument panel 16 and the knee K, and restrains the relative movement of the knee K forward of the vehicle. The main bag 26 and the sub bag 28 of the airbag 20 are integrally configured as shown in FIGS.

  Specifically, the main bag 26 is formed so as to be inflated and deployed in a bag shape by a first base cloth 30 that constitutes an upper portion and an intermediate portion of the airbag 20 in the vehicle vertical direction. In this embodiment, the main bag 26 is a so-called twin chamber structure airbag in which left and right bags adjacent in the vehicle width direction are connected as shown in FIG. The main bag 26 is formed such that the rear ends of the left and right bags (chambers) restrain the left and right shoulders (or the vicinity thereof) of the seated occupant P, respectively.

  The sub-bag 28 is formed in a bag-like shape that opens upward in the vehicle and is thinner than the main bag 26 by the second base cloth 32, and the opening edge is a vehicle lower opening edge of the main bag 26. It is joined by sewing or the like (see the joint portion J between the first base fabric 30 and the second base fabric 32 shown in FIGS. 1 to 3). Thereby, the airbag 20 has comprised the big bag shape as a whole. The second base fabric 32 is different from the first base fabric 30 in that the surface is subjected to a texture seal process as a texture seal structure such as a silicon coat, and gas leakage from the sub-bag 28 via the texture is prevented. It is prevented (suppressed with respect to the first base fabric 30). From the viewpoint of preventing gas leakage, the silicon coating for maintaining the internal pressure of the sub bag 28 is preferably applied to the side of the second base fabric 32 that is the inner surface of the sub bag 28.

  As described above, the airbag 20 deployed as a large bag as a whole has a tether 34 as a cloth-like material for partitioning (separating) the interior into a chamber of the main bag 26 and a chamber of the subbag 28. The tether 34 has a cloth shape and regulates the expansion of the sub bag 28 in the vehicle front-rear direction as shown in FIGS. 1 and 2. Further, a tether or a strap for restricting the expansion (thickness) of the sub-bag 28 in the vehicle front-rear direction may also be provided in a portion that is a substantially middle portion in the vehicle vertical direction in the deployed state in the sub-bag 28.

  The airbag 20 constituting the passenger seat airbag apparatus 10 includes an inner tube 35 as a flexible gas flow path member that guides the gas of the inflator 22 to the main bag 26 and the subbag 28. The inner tube 35 is a third base cloth 36 that is the same fabric as the first base cloth 30, and is independent of the main bag 26 and the sub bag 28, in front of the vehicle and below the vehicle as shown in FIG. It is configured as a bag body that is inflated and deployed in a substantially “U” shape that opens toward the front. Specifically, as described above, the inner tube 35 includes an upper portion 38 extending in the opening direction from the airbag case 24 that opens rearward and upward of the vehicle, and from the upper portion 38 to the front of the vehicle and to the lower side of the vehicle. The lower part 40 which is unfolded so as to be folded is configured as a main part.

  A lower portion 40 of the inner tube 35 penetrates the tether 34, and a gas supply port 40A for supplying gas to the sub bag 28 is formed at the tip thereof. On the other hand, a gas supply port 38 A for supplying gas to the main bag 26 is formed in the vicinity of the folded portion of the lower portion 40 in the upper portion 38 of the inner tube 35, that is, on the main bag 26 side with respect to the tether 34. In this embodiment, as shown in FIG. 3, the gas supply ports 38 </ b> A are formed as through holes that penetrate the third base cloth 36 on both sides in the vehicle width direction of the upper portion 38 of the inner tube 35. Thus, in the passenger seat airbag apparatus 10, gas is supplied into the main bag 26 from the upper portion 38 of the inner tube 35 toward both sides in the vehicle width direction.

  Further, in the passenger airbag device 10, a check valve (one-way valve) 42 is formed around the gas supply port 40 </ b> A in the lower portion 40 of the inner tube 35 as gas discharge suppression means. The check valve 42 has a cloth piece 42A that covers the gas supply port 38A from the inside of the sub bag 28, and allows gas supply to the sub bag 28 from the upper part 38 through the gas supply port 38A. On the other hand, the check valve 42 is configured such that when the internal pressure (dynamic pressure) of the sub bag 28 becomes higher than the internal pressure of the upper portion 38, the cloth piece 42A closes the gas supply port 38A by the internal pressure. In order to facilitate understanding of the configuration of the check valve 42, the gas supply port 40 </ b> A in the non-operating state of the check valve 42 is opened in FIG. 3, and the gas supply port 40 </ b> A by the check valve 42 in FIG. The closed state is illustrated.

  By setting the check valve 42, the vent hole 25, and the like, the passenger seat airbag apparatus 10 is configured such that the internal pressure of the sub bag 28 is higher than the internal pressure of the main bag 26 in the deployed state (occupant restrained state). ing. The main bag 26 has an internal pressure that increases as the knee K is restrained. However, as described above, the second base fabric 32 is subjected to the texture sealing process to maintain a high internal pressure (to prevent gas leakage or It is remarkably suppressed).

  The passenger seat airbag device 10 includes a tension relaxation structure (energy absorption portion) 45 for relaxing a load (tension) in a direction in which the main bag 26 and the subbag 28 of the airbag 20 are pulled up and down. As shown in FIG. 2, the tension relaxation structure 45 includes a folded portion 46 as a folded portion formed by folding a part of the rear surface facing the occupant P side of the first base fabric 30 constituting the main bag 26 up and down, A tear seam 48 formed by sewing the folded portion 46 is configured as a main part.

  A tear seam 48 that maintains (restrains) the folded portion 46 in a folded state is configured to be broken when a vertical tension of a predetermined value or more acts on a portion including the tension relaxation structure 45 in the first base fabric 30. . When the tear seam 48 is broken, the tension relaxation structure 45 is released from the restrained state by the tear seam, the folded portion 46 is expanded vertically, and the tension acting on the first base fabric 30 is relaxed by the deployment of the folded portion 46 ( Reduced). The deployed direction of the folded portion 46 is a direction along the deployed shape between the joint portion J of the sub bag 28 and the portion 26H where the occupant's head H of the main bag 26 contacts, and the tension relief structure 45. Can be regarded as the front-rear direction in the configuration in which is disposed close to the joint J. The folded-back portion 46 of the tension relaxation structure 45 in the passenger seat airbag device 10 can also be regarded as an extension portion of the first base fabric 30 due to a tension of a predetermined value or more.

  The tension relaxation structure 45 described above is set within a range A shown in FIG. 1 in a side view. Here, the range A is set between a portion 26 </ b> H where the occupant's head H of the airbag 20 contacts and a joint J between the main bag 26 and the subbag 28. The tension relaxation structure 45 is desirably disposed closer to the joint J than the portion 26H within the range A. In this embodiment, the tension relaxation structure 45 is as close as possible to the joint J (within the constraints). Has been placed.

  Further, as shown in FIG. 1, an airbag door 44 is formed at the portion of the instrument panel 16 to which the airbag module 18 is attached, and is opened by being broken by the inflation and deployment pressure of the airbag 20. The airbag door 44 according to this embodiment is opened up and down around the hinge portion when the instrument panel 16 is cleaved at a groove-like tear line formed on the inner surface thereof, and the instrument panel 16 is opened. It comes to form. Through this opening, the airbag 20 is allowed to be inflated and deployed outside the instrument panel 16, that is, in the passenger compartment C.

  In the passenger-side airbag device 10 described above, for example, when a frontal collision of the vehicle V is detected or predicted to be unavoidable based on an output of a collision sensor (not shown), an airbag as a control device (not shown) is used. The ECU operates the inflator 22.

  Next, the operation of this embodiment will be described.

  In the passenger airbag device 10 configured as described above, when a frontal collision of the automobile V is detected or predicted based on a signal from the collision sensor, the airbag ECU activates (ignites) the inflator 22. Then, the airbag 20 that has received the gas supply from the inflator 22 is inflated in the instrument panel 16 and inflated and deployed in the vehicle compartment C through an opening formed by deploying the airbag door 44 with the deployment pressure.

  At this time, the inner tube 35 supplied with the gas of the inflator 22 is first inflated and deployed. The gas from the inflator 22 is supplied to the main bag 26 through a gas supply port 38A formed in the upper portion 38 of the inner tube 35 and is supplied to the sub bag 28 through a gas supply port 40A formed in the lower portion 40.

  Then, the sub bag 28 is inflated and deployed between the instrument panel 16 and both knees K of the occupant P by gas supply through the gas supply port 40A. On the other hand, the deployment of the main bag 26 having a relatively large capacity is completed in front of the vehicle with respect to the upper body U of the occupant P after the deployment of the sub bag 28 is completed.

  As described above, in the passenger seat airbag apparatus 10, the inner tube 35 is provided in the airbag 20 including the main bag 26 and the subbag 28. Gas is supplied directly (independently) to each of the main bag 26 and the sub-bag 28. As a result, in the passenger seat airbag device 10, the relatively small-capacity sub-bag 28 is inflated and deployed in a short time from the operation of the inflator 22. Therefore, in the passenger seat airbag device 10, the subbag 28 can be inflated and deployed in a short time from the detection of the frontal collision in front of the vehicle with respect to the knee K of the seated occupant P with a small space (stroke) in the vehicle longitudinal direction. .

  The sub-bag 28 restrains the knee K and reduces the load acting on the knee K from the instrument panel 16 side. That is, the knee K of the seated occupant P is protected. In particular, in the passenger airbag device 10, the check valve 42 is provided on the gas supply port 40 </ b> A side in the lower portion 40 of the inner tube 35, so that the internal pressure of the sub-bag 28 increases as the knee K is restrained. The check valve 42 closes the gas supply port 40A. For this reason, a decrease in the internal pressure (gas discharge) of the sub-bag 28 accompanying the restraint of the knee K is suppressed, and the knee K of the seated occupant P is better protected.

  On the other hand, the head H and the upper body U of the occupant P are restrained by the inflated and deployed main bag 26, and shock absorption is achieved. Accordingly, the passenger P is well protected by the passenger seat airbag device 10. In particular, in the passenger seat airbag apparatus 10, gas is supplied toward both sides in the vehicle width direction in the main bag 26 through the left and right gas supply ports 38A. For this reason, compared with the configuration in which gas is supplied to the rear of the vehicle, the deployment force (deployment speed) of the main bag 26 toward the rear of the vehicle is suppressed, and the head H and the upper body U of the seated occupant P are restrained. The load is reduced.

  By the way, a load that pulls the first base fabric 30 forward and upward acts on the contact portion 26H of the head H in the main bag 26 that restrains the head H of the occupant P. On the other hand, a load that pulls the second base fabric 32 forward and downward acts on the portion of the sub bag 28 that restrains the knee K of the occupant P that is in contact with the knee K. That is, a load (tension) for pulling the main bag 26 and the sub bag 28 up and down acts on the airbag 20 in the restraining process of the head H and knees K of the occupant P. In the case of the comparative example that does not include the tension relaxation structure 45, a large load is applied to the joint portion J (contact portion of the knee K) formed by sewing the first base fabric 30 and the second base fabric 32 on the rear surface side of the airbag 20. (Stress) will act. Supplementally, the sub-bag 28 in which the internal pressure is relatively high due to the restraint of the knee K is configured by the second base fabric 32 that has been subjected to a texture seal process in order to maintain the internal pressure. It is joined to the main bag 26 composed of 30 by sewing at the joint J. In the case of the comparative example that does not include the tension relief structure 45 in order to adopt this structure, the airbag 20 is configured so that stress is likely to concentrate on the joint portion J, and as a countermeasure against this, reinforcement of the sewing site (multiplexing of sewing, etc.) is performed. I need it.

  Here, in the airbag device 10 for the passenger seat, the tension relief structure 45 is set between the joint portion J and the portion 26H where the head of the occupant contacts the rear surface of the main bag 26 facing the occupant P side. . For this reason, as described above, the first base fabric 30 is tensioned to a predetermined value or more by a load that pulls the main bag 26 and the subbag 28 up and down on the airbag 20 in the restraining process of the head H and knees K of the occupant P as described above. Acts, the tear seam 48 is broken and the folded portion 46 is developed. Thereby, the tension | tensile_strength which acts on the 1st base fabric 30 is relieve | moderated, and the load (stress) which acts on the junction part J of the main bag 26 and the subbag 28 is relieve | moderated. That is, in the airbag device 10 for the passenger seat, without relying on a reinforcing structure that reinforces the joint portion J by sewing the main bag 26 (first base fabric 30) and the subbag 28 (second base fabric 32), The required bonding strength between the main bag 26 and the sub bag 28 can be obtained.

  In particular, in the passenger seat airbag device 10, since the tension relaxation structure 45 is disposed closer to the joint portion J than the contact portion 26 </ b> H with the head H in the main bag 26, the load acting on the joint portion J (Stress) can be alleviated more effectively.

  Further, in the passenger seat airbag device 10, the load (stress) acting on the joint portion J as described above can be effectively applied by the tension relief structure 45 having a simple structure including the folded portion 46 and the tear seam 48 as main parts. Can be relaxed.

  Thus, in the passenger seat airbag apparatus 10 according to the embodiment of the present invention, the head H and the knee K of the occupant P by the main bag 26 and the sub bag 28 without depending on the reinforcing structure that reinforces the joint J. As a result, the bonding strength of the main bag 26 and the sub-bag 28 against the load acting when restraining is secured.

(Tension relaxation structure modification)
Next, the tension relaxation structures 50 and 60 according to the modification will be described.

  FIG. 4 is a side sectional view showing a tension relaxation structure 50 according to the first modification. As shown in this figure, the tension relaxation structure 50 has a concave shape as a folded portion formed by folding a part of the rear surface facing the occupant P side of the first base fabric 30 constituting the main bag 26 into the main bag 26. And the tear seam 48 formed by sewing the opening side of the folded portion 52 (the upper and lower ends of the folded folded portion 52). In the tension relaxation structure 50, when the tear seam 48 is broken, the folding portion 52 is expanded vertically, and the tension acting on the first base fabric 30 is relaxed by the expansion of the folding portion 52.

  FIG. 5 is a side sectional view showing a tension relaxation structure 60 according to a second modification. As shown in this figure, the tension relaxation structure 60 is mainly composed of a folded portion 46 and holding cloths 62 sewn on the first base fabric 30 on both upper and lower sides of the folded portion 46. At least one sewing portion of the holding cloth 62 with respect to the first base cloth 30 is formed by sewing with a tear seam 48. In this embodiment, the holding cloth 62 is sewn to the first base cloth 30 with a tear seam 48 at the upper portion of the folded portion 46. Further, in this embodiment, the holding cloth 62 is sewn (co-sewn) to the first base cloth 30 at the joint portion J on the lower side with respect to the folded portion 46.

  In the tension relaxation structure 60 described above, when the tear seam 48 is broken, the folded portion 46 (the first base fabric 30 with the set) is unfolded up and down, and the unfolded portion 46 develops the first base fabric 30. The acting tension is relaxed. In the tension relaxation structure 60, the vertical length of the holding cloth 62 is set to be shorter than the vertical length of the first base cloth 30 including the folded portion 46 between the joint portion J and the tear seam 48. It can be grasped as a thing.

  That is, the tension relaxation structure 60 may be configured such that the folded state of the folded portion 46 is not maintained. Further, in the tension relaxation structure 60, the lower end of the holding cloth 62 may be bonded to the upper side of the bonding portion J, and the holding cloth 62 may be formed to extend from the second base cloth 32 (integrally). . In the former case, the tear seam 48 may be disposed below the folded portion 46.

  In the above-described embodiment, the main bag 26 and the sub bag 28 are each shown in the example in which the gas from the inflator 22 is directly supplied through the inner tube 35. However, the present invention is not limited to this, for example, A gas distribution structure (with a diffuser or the like) provided in the airbag case 24 may be configured to distribute the gas to the main bag 26 and the sub bag 28.

  Further, in the above-described embodiment, the example in which the check valve 42 is provided as the internal pressure holding (gas discharge suppression) means of the sub bag 28 has been shown, but the present invention is not limited thereto, for example, as the internal pressure holding means, You may employ | adopt the string etc. which close the lower part 40 of the inner tube 35 with the expansion | deployment deployment of the main bag 26 or the subbag 28. FIG.

  Furthermore, in the above-described embodiment, an example is shown in which the sub bag 28 is deployed ahead of the main bag 26 due to a difference in capacity between the main bag 26 and the sub bag 28 to which the gas from the inflator 22 is directly supplied. However, the present invention is not limited to this. For example, the gas supply port 38A is closed with a tear seam or the like that is broken by a gas pressure of a predetermined value or more, and the internal pressure of the inner tube 35 is increased (the sub bag 28 A deployment delay structure in which deployment of the main bag 26 is started in the deployment process or after completion of deployment may be provided.

  Furthermore, in the above-described embodiment, an example in which the main bag 26 is a so-called twin-chamber airbag in which the left and right bags are connected is shown. However, the present invention is not limited to this, and for example, the main bag 26 It is good also as a structure which is what is called a single chamber structure airbag which has a single chamber.

  Further, in each of the above-described embodiments, the example in which the airbag apparatus according to the present invention is applied to the airbag apparatus 10 for the passenger seat is shown. However, the present invention is not limited to this, for example, the airbag apparatus according to the present invention. The bag device can be applied to a seat in the center in the vehicle width direction among seats in which three passengers can be seated in the vehicle width direction. In addition, such a central seat can be regarded as being included in the passenger seat in the present invention.

10 Airbag device for passenger seat 26 Main bag (first bag)
26H The part where the head of the occupant contacts 30 First base fabric (base fabric)
45 Tension relief structure 46 Folding part (folding part)
48 Tear seam 50/60 Tension relief structure 52 Folding part (folding part)
J joint

Claims (4)

A first bag that restrains the upper body of the vehicle occupant from the front side in the vehicle front-rear direction by being inflated and deployed upon receiving gas supply;
A second bag that has a smaller capacity than the first bag, is joined to the first bag, is inflated and deployed by receiving gas supply, and restrains the occupant's knee from the front side in the vehicle front-rear direction;
Between the portion where the head of the occupant contacts the portion of the base fabric that constitutes the first bag that faces the occupant and the joining portion of the second bag, A tension relief structure provided so that the base fabric is expanded in the vertical direction when tension acts;
An airbag device comprising: The tension relaxation structure is
A fold formed to be deployable in the vertical direction between a portion of the base fabric facing the occupant and a portion where the occupant's head contacts and a joint portion of the second bag;
A tear seam that maintains the folded state of the folded portion by sewing and is broken by a vertical tension of a predetermined value or more that acts on a portion of the base fabric that includes the folded portion;
The airbag device according to claim 1, comprising:   The said tension relaxation structure is provided near the junction part with the 2nd bag in this base cloth rather than the part which the said passenger | crew's head contacts in the base cloth of the said 1st bag. 2. The airbag device according to 2.   The second bag is composed of a base fabric having a textured seal structure that suppresses gas leakage from the texture, and an internal pressure in a deployed state is higher than an internal pressure in a deployed state of the first bag. The airbag device according to any one of claims 1 to 3, wherein the airbag device is set as follows.

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