Side airbag system

Abstract

Side airbag device comprising: a gas generator (31) arranged in the vicinity of one side of the chest area (PT) of an occupant (P) seated in a vehicle seat (12) to expel filling gas in response to a shock exerted from a lateral direction of a vehicle (10), and an airbag (40) housed in a folded state in which folded sections (66, 68, 69, 72, 73) are formed and deployed by the filling gas from the gas generator (31) between an area extending from the chest area (PT) to the head (PH) of the occupant (P) and a side wall (11) of the vehicle (10).is unfolded and inflated, wherein a folded section (68) of a distal side of the airbag (40) is folded back in a direction along an axis (AL) of the gas generator (31) towards the interior of the vehicle, at least one section of the airbag (40) is folded from top to bottom to form folded sections (66, 68, 69) such that these are deployed or unfolded and inflated from bottom to top, and a folded section (68) at an upper end of the airbag (40) is folded back as the folded section (68) of the distal side in a direction along the axis (AL) of the gas generator (31) towards the interior of the vehicle.

Description

The present invention relates to a side airbag device that inflates and deploys an airbag in a space between an occupant seated in a vehicle seat and a side wall of the vehicle when an impact is applied to the vehicle from a lateral direction due to a side collision or the like, thereby protecting a region extending from a chest region to the head of the occupant from the impact.A side airbag device including an airbag and a inflator is widely known as a device capable of protecting an upper body of an occupant seated in a vehicle seat from an impact caused by a side collision or the like. The airbag and the inflator of the side airbag device are accommodated in a seat back (seat back) of the vehicle seat, the airbag being folded. When an impact is applied to a side wall, for example, a side door, of the vehicle from a lateral direction due to the side collision or the like, inflation gas is supplied from the inflator to the airbag. The airbag is deployed and inflated so as to jump out of the vehicle seat in a state where a portion of the airbag remains in the seat back. Thereafter, the airbag is deployed and inflated in a narrow space between the upper body of the occupant and the side wall of the vehicle. The airbag is interposed between the upper body of the occupant and the side wall moving toward an inner side of a vehicle interior to restrain the upper body of the occupant while absorbing the impact applied to the upper body via the side wall.An aspect of such a side airbag device is disclosed in Japanese Laid-Open Patent Publication JP 2007-203 939 A, for example. In the side airbag device, a inflator is disposed near the chest portion side of the occupant seated in the vehicle seat. When the inflation gas is ejected from the inflator in response to the impact such as a side collision or the like, the inflation gas flows upward and forward in the airbag of the folded state. By the inflation gas, the airbag is deployed and inflated in the forward and upward directions of the vehicle between the side wall of the vehicle and an area extending from a chest area to the head of the occupant seated in the vehicle seat.Further, a side airbag device capable of restraining and protecting other portions of the upper body of the occupant other than the portion of the upper body is disclosed in Japanese Patent Application Laid-Open JP 2007-203 939 A.In each of the side airbag devices disclosed in Japanese Patent Laid-Open Publication JP 2007-203 939 A and Japanese Patent Laid-Open Publication JP 2010-70 178 A, the folded portion of the upper end, which is a distal portion with respect to the deployment direction, is folded back in the state in which the airbag is folded.DE 10 2009 031 615 A1 discloses an airbag arrangement with an airbag, which has a first and a second chamber. The first chamber is divided into a first and a further region. The second chamber connects to the first chamber in a different direction. The second chamber is filled with gas via the first region of the first chamber, wherein the main gas flow direction corresponds to the direction of the second chamber. This is intended to ensure an effective, robust and timely positioning of the airbag.DE 197 31 729 A1 describes an airbag device and a method for folding an airbag. The airbag is first folded along a first fold line that is substantially parallel to the extension direction. Subsequently, a second folding portion thereof is folded along a second folding line substantially perpendicular to the extension direction. Upon expansion, the second folding portion expands before the first folding portion, whereby the airbag can promptly expand to securely protect an occupant.DE 198 34 666 A1 discloses a dual-chamber airbag for side impact protection and a method for producing the same. The airbag has an integrally formed intermediate wall which separates an upper and a lower chamber from one another. This intermediate wall is formed by forming a partial intermediate wall from a portion of each airbag part. When the airbag parts are assembled, the two partial partitions meet and are sewn together to form the integral partition.DE 603 19 427 T2 discloses a vehicle seat with a backrest which comprises an airbag unit. The airbag unit is mounted to the frame of the seat back such that the inflator is adjacent the rearmost region of the frame. In operation, the airbag inflates such that at least a portion of the airbag lies between the frame and an occupant, with a substantial length of the airbag pressing against the frame during inflation.US 6 142 507 A discloses a side airbag formed of front and rear fabric bodies and having a torso protection and a head protection portion. In order to prevent undesired pivoting of the head protection section during deployment, various solutions are proposed. One solution is an auxiliary section that simultaneously generates a counter pressure. Another solution is to fold the head and fuselage protection portion diagonally with respect to each other. Another disclosed solution uses fuse stitches (melt stitches) to delay deployment of the head guard portion until the fuselage guard portion is already deployed.However, in the side airbag device disclosed in Japanese Patent Laid-Open Publication JP 2007-203 939 A and Japanese Patent Laid-Open Publication JP 2010-70 178 A, when the inflation gas for inflating the airbag is supplied, the folded portion of the folded-back upper end of the airbag may be deployed toward the vehicle outer side. In this case, in the process in which the folded-back state of the folded portion of the upper end of the airbag is released (deployed), the folded-back upper end comes into contact with the side wall of the vehicle, so that the smooth deployment can be interrupted by friction.In the airbag deployed and inflated by the inflation gas from rear to front, the above-described problem may similarly occur also in the case where the front end folded portion, which is a distal portion with respect to the deployment direction, is folded back.The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a side airbag device that can deploy and fill a folded portion of a distal portion with respect to a deployment direction of an airbag.In order to solve the above-mentioned problems, there is provided a side airbag device according to claim 1. The dependent claims relate to further advantageous embodiments of the invention.With the above configuration, when the impact is applied to the vehicle from the lateral side due to the side collision or the like, the inflation gas is discharged from the inflator. The inflator gas is supplied from the folded portion close to the inflator to the folded portion away from the inflator, and therefore the folded portions are unfolded (discharged) and filled in this order. And, when the inflation gas is supplied to the folded portion of the distal side of the airbag with respect to the deploying direction, the folded portion is inflated while the state of the unfolding to the vehicle inner side is released (deployed). During the deploying and filling, since the folded portion of the distal side does not come into contact with the side wall of the vehicle, the disruption of the unimpeded deployment due to the friction with the side wall hardly occurs.In the side airbag device, preferably, at least a portion of the airbag is folded from top to bottom so that the plurality of folded portions are formed to be deployed and inflated from bottom to top, and the folded portion of the upper end of the airbag is folded back toward the vehicle inner side as the folded portion of the distal side with respect to the deployment direction.With the above configuration, at least a part of the inflation gas discharged from the inflator is supplied from the folded portion of the lower portion to the folded portion of the upper portion in response to the impact from the lateral direction of the vehicle. By the inflation gas, the airbag is inflated while sequentially releasing (deploying) the fold from the folded portion of the lower portion to the folded portion of the upper portion. When the inflation gas is supplied to the folded portion of the upper end with respect to the deployment direction of the airbag, the folded portion is released (deployed) from the state of being folded back toward the vehicle inner side. During deployment, since the folded portion of the upper end does not come into contact with the side wall of the vehicle, the interruption of the unimpeded deployment due to the friction with the side wall hardly occurs.In the side airbag device, it is preferable that the airbag is divided into a front inflation chamber before the division and a rear inflation chamber behind the division by a partition extending in a substantially vertical direction, the inflator is disposed at a lower portion of the rear inflation chamber, the partition is provided with an upper communication hole for communicating rear inflation chamber and front inflation chamber at a portion that is a head side of an occupant, the partition is provided with a lower communication hole for communicating rear inflation chamber and front inflation chamber at a portion that is a chest region side of the occupant, and a region of the airbag folded from top to bottom that is before the partition is folded from front to back in a roll-folding manner, which folds the portion repeatedly in the same direction, and a portion behind the partition is folded from front to back in a bellows folding manner changing a folding direction alternately.With the configuration stated above, at least a part of the gas discharged from the inflator flows up and forward in the rear inflation chamber in response to the impact from the lateral direction of the vehicle. By the filling gas, the bellows-folded portion behind the partition is deployed or unfolded and filled toward the front side. Here, bellows folding is characterized in that the folded state is easily released. For this reason, the bellows-folded portion behind the partition is rapidly deployed and filled toward the front side from the side of the chest region or the head of the occupant, thereby rapidly restraining and protecting the region of the occupant.A part of the inflation gas that flows upward in the rear inflation chamber 46 and arrives at the side of the rear portion of the occupant's chest region flows downward through the lower communication hole in the front inflation chamber. Also, a part of the inflation gas that flows upward outside the lower communication hole in the rear inflation chamber without passing through the lower communication hole and arrives at the rear portion side of the head of the occupant flows upward through the upper communication hole in the front inflation chamber. By the filling gas, the roll-folded portion is deployed or unfolded and filled toward the front side before the division. Here, the roll folding is characterized in that the folded portion is easily unfolded along the side wall of the vehicle. In this way, the roll-folded portion is deployed and filled on the side of the front portion of the chest region or the head of the occupant before being divided along the side wall of the vehicle, thereby correctly restraining and protecting the region of the occupant.In the side airbag device, it is preferable that at least a lower portion of the airbag is folded from front to rear so that the plurality of folded portions are formed to be deployed and inflated from rear to front, and the folded portion of a lower front end of the airbag is folded back toward the vehicle inner side as the folded portion of the distal side with respect to the deployment direction.With the above configuration, in response to the impact from the lateral direction of the vehicle, at least a part of the inflation gas ejected from the inflator is supplied from rear to front in the lower portion of the airbag. By the inflation gas, the lower portion of the airbag is sequentially deployed from the folded portion of the rear portion to the folded portion of the front portion. When the inflation gas is supplied to the folded portion of the lower front end, which is the distal side with respect to the deployment direction of the airbag, the folded portion is released (deployed) from the state of being folded back toward the vehicle inner side. During deployment, since the folded portion does not come into contact with the side wall of the vehicle, the interruption of the unimpeded deployment due to the friction with the side wall hardly occurs.In the side airbag device, it is preferable that the airbag is divided into a front inflation chamber before the division and a rear inflation chamber behind the division by a partition extending in a substantially vertical direction, the inflator is disposed at a lower portion of the rear inflation chamber, the partition is provided with a lower communication hole for communicating the rear inflation chamber and the front inflation chamber at a portion that is a side of the chest region of the occupant, and the folded portion of the lower front end of the airbag is folded back while crossing the partition.With the above configuration, in response to the impact from the lateral direction of the vehicle, at least a part of the inflation gas discharged from the inflator is supplied in the rear inflation chamber from rear to front. By the inflation gas, the lower portion of the rear inflation chamber is sequentially deployed from the folded portion of the rear portion to the folded portion of the front portion. The inflation gas firstly inflates the portion (behind the partition) of the lower front end folded portion that is the distal side with respect to the airbag deployment direction.Also, a part of the inflation gas discharged from the inflator flows upward in the rear inflation chamber. When the inflation gas flows upward in the rear inflation chamber and arrives at the portion that is the side of the chest region of the occupant, the inflation gas flows to the portion (before division) of the folded portion of the lower front end through the lower communication hole. By the inflation gas, the folded portion folded back toward the vehicle inner side is released (deployed). In this case, the portion (before division) of the folded portion is pushed by the portion behind the division starting to be filled first, whereby the unfolding is performed quickly.According to the side airbag device, since the folded portion of the distal portion is folded back toward the vehicle inner side with respect to the deployment direction of the airbag, the folded portion can be deployed freely. FIG. 1 is a side view illustrating an occupant and a vehicle seat provided with a side airbag device according to an embodiment of the present invention; FIG. 2 is a plan view in section illustrating a positional relationship among the vehicle seat, the airbag, the occupant, and a side wall of the vehicle according to the embodiment; FIG. 3 is a front sectional view illustrating a positional relationship among the vehicle seat, the airbag, the occupant, and the side wall of the vehicle according to the embodiment; FIG. 4 is a partial plan view in section illustrating an internal structure of a side portion of a seat back in which an airbag module is accommodated according to the embodiment; FIG. 5 is a side view illustrating the airbag module in a state where the airbag is deployed but not yet inflated according to the embodiment; FIG. 6 is a plan view in section schematically illustrating the internal configuration of the airbag according to the embodiment; FIG. 7 is a partial side elevational view in section illustrating the internal structure of the airbag module in FIG. 5 together with the occupant and the vehicle seat; FIG. 8 is a side view illustrating the state before the airbag of the airbag module according to the embodiment is not folded; FIGS. 9A and 9B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, wherein FIG. 9A is a side view and FIG. 9B is a rear view when viewed from a left side of FIG. 9A ; FIGS. 10A and 10B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, wherein FIG. 10A is a side view and FIG. 10B is a rear view when viewed from a left side of FIG. 10A ; FIGS. 11A and 11B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, wherein FIG. 11A is a side view and FIG. 11B is a rear view when viewed from a left side of FIG. 11A ; FIGS. 12A and 12B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, in which FIG. 12A is a side view as viewed from a rear side of FIG. 11A and FIG. 12B is a rear view as viewed from a right side of FIG. 12A ; FIGS. 13A and 13B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, in which FIG. 13A is a side view and FIG. 13B is a sectional view taken along line A-A in FIG. 13A ; FIGS. 14A and 14B are diagrams illustrating a state of folding the airbag in the airbag module according to the embodiment, wherein FIG. 14A is a side view and FIG. 14B is a sectional view taken along the line B-B in FIG. 14A ; FIGS. 15A and 15B are diagrams illustrating the folded airbag accommodated in the airbag module according to the embodiment, in which FIG. 15A is a side view and FIG. 15B is a sectional view taken along line C-C in FIG. 15A ; FIG. 16 is a partial plan view in section illustrating a state in which the airbag is deployed and inflated after jumped out of the vehicle seat, leaving a part of the airbag in the seat back; FIG. 17 is a side view illustrating a positional relationship between a fold line and a folded portion in the airbag according to the embodiment; and FIG. 18 is a diagram corresponding to FIG. 11B and is a rear view illustrating a modification of an airbag of which a folded portion of a distal portion (upper end) is folded in an aspect different from the embodiment.Description of Reference Numerals10 Vehicle 11 Side wall 12 Vehicle seat 31 Inflator 40 Airbag 46 Rear inflation chamber 47 Front inflation chamber 50 Partition 54 Upper communication hole 55 Lower communication hole 66, 68, 69, 72, 73 Folded portion P Occupant PH Head PT Chest region Z 1, Z 2 RegionNext, a side airbag device according to an embodiment will be described with reference to FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 to 17.Hereinafter, the direction in which a vehicle advances will be referred to as a forward direction, and the terms front, rear, upper (upward), lower (downward), left and right will be defined with reference to the forward direction. Also, in each drawing, front indicates a front side of the vehicle, rear indicates a rear side of the vehicle, inside indicates an inner side of the vehicle, and outside indicates an outer side of the vehicle. The inner side of the vehicle is a side that is close to the central axis of the lateral direction of the vehicle with respect to the lateral direction of the vehicle, and the outer side of the vehicle is a side that is spaced apart from the central axis.Also, it is assumed that an occupant (adult) having a standard body structure is seated in a vehicle seat in a predetermined posture (normal posture).As illustrated in FIGS. 1, 2 to 3, a vehicle seat 12 is located in the vicinity of the vehicle inner side of a side wall 11 in a vehicle 10. For example, the side wall 11 corresponding to a front seat includes a front door and a center pillar (B pillar). Also, the side wall 11 corresponding to a rear seat includes a rear portion of a side door (back door), a C-pillar, a front portion of a wheel house, and a rear quarter panel ("rear quarter panel").The vehicle seat 12 includes a seat cushion (seat part) 13 and a seat back (backrest) 14 that extends upward from a rear side of the seat cushion 13, and an inclination angle of the seat back 14 is adjusted by a reclining mechanism (not shown). The vehicle seat 12 is disposed in the vehicle 10 with the seat back 14 facing forward. The lateral direction of the vehicle seat 12 arranged in this manner coincides with the lateral direction of the vehicle.The seat back 14 includes a seat back body 15 and a pair of side support portions 16 provided on both sides of the seat back body 15 in the lateral direction of the seat back body 15. The seat back body 15 is inclined rearward to support a torso of an occupant P from behind. Both side support portions 16 project from the seat back body 15 to restrain movement of the upper body of the occupant seated on the seat cushion 13 and inclined against the seat back body 15 from movement in the lateral direction of the vehicle.Next, the internal structure of the seat back 14, specifically, the vehicle exterior side portion including the vehicle exterior side support portion 16 will be described.A seat frame forming a framework of the seat back 14 is installed in the seat back. A portion of the seat frame is located on the vehicle exterior of an inner space of the seat back 14 as illustrated in FIG. 4. The portion of the seat frame is referred to as a side frame portion 17 and is formed by bending a metal sheet. A seat pad 18 made of an elastic material such as urethane foam is disposed in front of the seat frame including the side frame portion 17. A back plate 19 made of a hard material such as a synthetic resin is provided behind the seat frame. Although the seat pad 18 is padded by padding, the padding is not shown in FIG. 4. The same applies to FIG. 16 described below.An accommodation portion 21 is provided in the seat pad 18 at a position adjacent to the vehicle exterior side of the side frame portion 17. The position of the accommodation portion 21 is a central portion of the seat back 14 in the up / down direction, and is located obliquely rearward of the occupant P seated in the vehicle seat 12 (see FIG. 2 ). An airbag module AM constituting a main part of the side airbag device is accommodated in the accommodation portion 21.A slit 22 extends diagonally forward and outward from the vehicle outer side and the front corner of the accommodation portion 21. A portion of the seat pad 18 located between a front corner 18C of the seat pad 18 and the gap 22 (i.e., a portion surrounded by a dashed / two-dot line in FIG. 4 ) forms a breakable portion 23 to be broken by the airbag 40, which will be described below.The airbag module AM installed in the seat back 14 includes a inflator assembly 30 and the airbag 40 as its main components. Next, each of the components will be described.Inflator Assembly 30The inflator assembly 30 includes an inflator 31 serving as a gas generation source and a container or receptacle 32 covering the inflator 31. In this embodiment, a pyrotechnic gas generator is used as the gas generator 31. The inflator 31 is formed in a generally cylindrical shape and contains therein a gas generating agent (not shown) for generating a inflation gas.In place of the pyrotechnic gas generator using the gas generating agent, it is possible to use a hybrid type gas generator that breaks a division of a high-pressure gas cylinder filled with a high-pressure gas by an explosive to expel gas.On the other hand, the container 32 functions as a diffuser for controlling the discharge direction of the inflation gas and also as a member for fixing the inflator 31 to the side frame portion 17 together with the airbag 40. most parts of the container 32 are formed in a substantially cylindrical shape extending in a substantially vertical direction obtained by bending a plate such as a metal sheet. The container 32 is provided with a communication portion (not shown) for connecting inner and outer sides of the container. Most parts of the inflation gas discharged from the inflator 31 are discharged to the outside from the container 32 via the communication portion.The container 32 is secured to the side frame 17 by a securing member such as bolts 34.The inflator assembly 30 may be configured such that the inflator 31 and the container 32 are integrally formed in one piece.Airbag 40As illustrated by the dashed / two-dot lines in FIGS. 1, 2 to 3, when an impact is applied to the side wall 11 from a lateral direction due to a side collision or the like while the vehicle 10 is traveling, the airbag 40 is supplied with the inflation gas from the inflator 31 and therefore deployed and inflated, so that the airbag 40 is jumped out from the seat back 14 in a state where a portion of the airbag 40 remains in the seat back 14.FIG. 5 is a side view illustrating the airbag module AM in a state (hereinafter referred to as an unfilled deployed state) in which the airbag 40 is deployed in a flat shape without being filled with the inflation gas. FIG. 7 illustrates the internal structure of the airbag module AM together with the occupant P and the seat 12, the airbag 40 being cut at the center of the lateral direction of the vehicle in the non-inflated, deployed, or deployed state in FIG. 5.As illustrated in FIGS. 5, 6 to 7, the airbag 40 is formed by folding one fabric layer (base fabric, also known as a fabric sheet) halfway along a fold line 42 disposed on a center line of the fabric to superimpose the fabric in the vehicle transverse direction, and then connecting the superimposed portions of the fabric to form the shape of a bag. To distinguish two superposed portions of the airbag 40, the fabric placed on the vehicle inner side is referred to as the fabric portion 43, and the fabric placed on the vehicle outer side is referred to as the fabric portion 44. Each of the fabric portions 43 and 44 is formed in a vertically elongated shape with respect to the front and rear direction.According to this embodiment, the fabric is folded halfway such that the fold line 42 is located at a rear end of the airbag 40, but the fabric may be folded halfway such that the fold line 42 is located at another end of the airbag 40, for example, a front end, an upper end, or a lower end thereof. Also, the air bag 40 may be comprised of two panels of fabric divided along the fold line 42. In this case, the airbag 40 is formed by laying one fabric part on the other in the vehicle transverse direction and connecting the two fabric parts to form the shape of a bag. Further, the airbag 40 may be made of three or more fabric pieces.In the airbag 40, the appearance of the two fabric portions 43 and 44 is axis-symmetrical with respect to the fold line 42. the shape and size of each fabric portion 43 and 44 are configured such that the airbag 40 includes the region corresponding to the region from the chest region PT to the head PH in the upper body of the occupant P seated in the vehicle seat 12 when the airbag 40 is deployed and inflated between the vehicle seat 12 and the side wall 11 (see FIGS. 1, 2 to 3 ). As illustrated in FIG. 7, the airbag 40 is configured such that a front end 40 aof the portion corresponding to a side of the head PH of the occupant P is positioned in front of the front end 40 bof the portion corresponding to a side of the chest region PT.A material suitable for the above-mentioned fabric portions 43 and 44 includes a woven fabric made of, for example, a polyester yarn or polyamide yarn, which has high strength and flexibility and can be easily folded.The two fabric portions 43 and 44 are joined together along a peripheral edge joint portion 45 provided at peripheral edges of the fabric portions 43 and 44. In this embodiment, most of the peripheral edge connecting portion 45 is formed by stitching (sewing together with a sewing thread) the peripheral edges of the fabric portions 43 and 44 except for the rear ends thereof (i.e., the vicinity of the fold line 42). The configuration formed by the stitching is similar to an outer connection portion 52 and an inner connection portion 53 described later.In FIGS. 5, 7 to 15B, and 17, the stitched portions of the airbag 40 are represented by three kinds of lines. The first of these lines is a line (a kind of broken line) represented by intermittently aligning or directionally arranging thick lines of a given length, and it shows the quilted portions as viewed from the airbag 40 side (see the peripheral edge connecting portion 45 or the like in FIG. 5 ). The second of these lines is a line (a kind of broken line) represented by intermittently aligning or directionally arranging thin lines of a given length (longer than a general broken line), and it shows a state in which the sewing thread is positioned between the fabric portions 43 and 44 and therefore is not directly seen (hidden) (see the inner connecting portion 53 or the like in FIG. 5 ). The third of these lines is a line (a kind of broken line) represented by aligning or aligning points at regular intervals, and it shows a cross section of the suture that stitches the fabric portions 43 and 44 together (see the peripheral edge connecting portion 45 in FIG. 7 ).As shown in FIGS. 5, 6 to 7, the space enclosed by the peripheral edge connecting portion 45 between the two fabric portions 43 and 44 forms a inflation portion deployed and inflated by the inflation gas on the upper body side of the occupant P to protect the region extending from the chest region PT and the head PH from the shock.In this case, the peripheral edge connecting portion 45 may be formed by a means other than the stitching using the suture, for example, by bonding using an adhesive. The configuration formed by the bonding is similar to the outer joint portion 52 and the inner joint portion 53 described later.The airbag 40 is provided with a partition 50 at the inner central portion thereof in a longitudinal direction, and the partition extends in a substantially vertical direction. Therefore, the airbag 40 is divided into a rear inflation chamber 46 at a position rearward of the partition 50, and a front inflation chamber 47 at a position forward of the partition 50. The partition 50 has the same configuration as one generally referred to as a link ("tether").Division 50The partition 50 comprises a pair of fabric parts 51 of a material having high strength and flexibility and being easily folded, for example, the same woven fabric as the fabric portions 43 and 44. Each fabric member 51 is connected to the opposite one of the two fabric portions 43 and 44 of the airbag 52 through the outer connecting portion 52 extending in the substantially vertical direction along the rear edge thereof. When the airbag 40 is inflated, the two outer joint portions 52 are joined to the fabric portions 43 and 44 corresponding to the rear end of the fabric part 51 at the portion that is the side of the central portion in the horizontal direction in the upper body of the occupant P. Both fabric pieces 51 are joined together by the inner joint portion 53 extending in the substantially vertical direction along the front edge thereof.The partition 50, which is made of a pair of fabric pieces 51, is interposed between the vehicle inner side fabric portion 43 and the vehicle outer side fabric portion 44 in the airbag 40. The partition 50 is in the superimposed state in the vehicle lateral direction when the airbag 40 is in the non-inflated deployed state (see FIGS. 5 and 7 ). Also, the partition 50 is strained in the vehicle lateral direction when the airbag 40 is inflated (see FIG. 6 ), and therefore, limits the thickness (inflation thickness) of the airbag 40 in the vehicle lateral direction.The partition 50 is provided with an upper communication hole 54 for communicating the rear inflation chamber 46 and the front inflation chamber 47 in the portion that is the head PH side of the occupant P when the airbag 40 is inflated. Also, the partition 50 is provided with a lower communication hole 55 for communicating the rear inflation chamber 46 and the front inflation chamber 47 at the portion that is the chest region PT side of the occupant P when the airbag 40 is inflated. Specifically, the inner connecting portion 53 connecting both fabric parts 51 is not engaged at two portions, i.e., the upper end and the lower end, in the vertical direction. The upper end and the lower portion in the vertical direction are not provided with the inner connecting portion 53 connecting the two fabric parts 51. The upper end non-engagement portion of the inner connection portion 53 forms the upper communication hole 54 and the lower portion non-engagement portion of the inner connection portion 53 forms the lower communication hole 55. The upper communication hole 54 and the lower communication hole 55 are closed in the state where both fabric parts 51 are superposed and opened in the state where the partition 50 is strained in the lateral direction of the vehicle when the airbag 40 is inflated.In the state where the airbag 40 is in the non-inflated deployed state, i.e., the fabric parts 51 are superposed on the partition 50, the vertical length L 1 of the lower communication hole 55 is longer than the vertical length L 2 of the upper communication hole 54.Most of the above-described inflator assembly 30 is housed in the lower portion of the rear end of the rear inflation chamber 46, the inflator assembly extending in a substantially vertical direction. The bolt 34 of the container 32 is inserted into the vehicle inner side fabric portion 43 of the airbag 40. With the insertion, the inflator assembly 30 is locked in a state of positioning with respect to the airbag 40.Further, the vehicle exterior side fabric portion 44 serves as the front portion of the front inflation chamber 47, and has a vent hole 56 between the upper communication hole 54 and the lower communication hole 55. The fabric portion 44 is provided with a reinforcing portion 57 in the vicinity of the vent hole 56, and the reinforcing portion 57 is formed by stitching it with the suture. The reinforcing portion 57 reinforces the vicinity of the vent hole 56 of the fabric portion 44 to prevent the portion from being burst or loosened.As illustrated in FIGS. 4, 15A, and 15B, the airbag module AM including the inflator assembly 30 and the airbag 40 as main components thereof is configured to have a compact shape (hereinafter referred to as a storage shape) in which the airbag 40 is folded. This serves to fit the airbag module AM into the restricted-size accommodation portion 21 in the seat back 14 for the purpose of appropriate accommodation.The storage shape is obtained by folding the airbag 40 of the non-inflated deployed state as shown in FIGS. 8 to 15B. Next, a process of folding the airbag 40 will be described, and specifications regarding the positions of the fold lines 42, 61, 64, 67, 71, 74, and 75, the positions of the portions to be folded, the folding direction, or the like are necessary. For this reason, when the positions of the fold lines or the positions of the portions to be folded are specified, each portion of the airbag 40 is specified based on the inflator assembly 30. With respect to a direction (substantially vertical direction) along an axis AL of the inflator assembly 30, the end near the inflator assembly 30 is referred to as a first proximal portion, while the end remote from the inflator assembly 30 is referred to as a first distal portion. In the state where the airbag 40 of the non-inflated deployed state is attached to the vehicle seat 12, the first proximal portion corresponds to the lower end of the airbag 40 and the first distal portion corresponds to the upper end of the airbag 40.Similarly, the direction (substantially horizontal direction) perpendicular to the axis AL of the inflator assembly 30 is referred to as a second proximal portion, while the end thereof remote from the inflator assembly 30 is referred to as a second distal portion. In the state where the airbag 40 of the non-inflated deployed state is attached to the vehicle seat 12, the second proximal portion corresponds to the rear end of the airbag 40 and the second distal portion corresponds to the front end of the airbag 40.When the folding direction is specified, the words "vehicle outer side" and "vehicle inner side" are used, assuming that the airbag 40 is mounted on the vehicle seat 12.FIG. 8 shows the airbag 40 of the non-inflated, deployed state as viewed from the vehicle exterior side, with the axis L of the inflator assembly 30 and the fold line 42 extending in the vertical direction. In the airbag 40, a fold line 61 perpendicular to the fold line 42 is provided at a portion slightly spaced from the inflator assembly 30 toward the first distal portion (upper side of FIG. 8 ). In the airbag 40, as indicated by the arrow in FIG. 8, the portion of the first distal portion (upper side of FIG. 8 ) except the fold line 61 is folded back toward the vehicle outer side (front side of FIG. 8 ) along the fold line 61. By folding back the portion 62, a part of the portion 62 is overlapped with a part of the portion 63 of the first distal portion (lower side of FIG. 8 ) except the fold line 61. Therefore, the airbag 40 is formed as shown in FIGS. 9A and 9B.Next, in the portion 62, the fold line 64 parallel to the fold line 61 is set at the portion spaced from the fold line 61 toward the first distal portion (lower side of FIG. 9A ). In the portion 62, as indicated by the arrow in FIG. 9A, the portion 65 of the first distal portion (lower side of FIG. 9A ) except the fold line 64 is folded back toward the vehicle outer side (front side of FIG. 9A ) along the fold line 64. By folding back the portion 65, a part of the portion 65 is overlapped with a part (hereinafter referred to as a folded portion 66) of the airbag 40 which is pinched between the fold line 61 and the fold line 64. Therefore, the airbag 40 is formed as shown in FIGS. 10A and 10B.The fold line 67 parallel to the fold line 64 is provided at the portion of the portion 65 spaced from the fold line 64 toward the first distal portion (upper side of FIG. 10A ). In the portion 65, as indicated by the arrow in FIG. 10A, the portion (hereinafter referred to as folded portion 68) of the first distal portion (upper side of FIG. 10A ) except the fold line 67 is folded back toward the vehicle inner side (rear side of FIG. 10A ) along the fold line 67. By folding back the portion 68, most of the portion 68 is overlapped with a part (hereinafter referred to as a folded portion 69) of the airbag 40 which is pinched between the fold line 64 and the fold line 67. Therefore, the airbag 40 is formed as shown in FIGS. 11A and 11B.FIGS. 12A and 12B show the airbag 40 in FIGS. 11A and 11B as viewed from a rear side thereof, i.e., as viewed from the vehicle inner side. As illustrated in FIGS. 12A and 12B, the fold line 71 is disposed at the portion 63 of the airbag 40 in which the inflator assembly 30 is accommodated. The fold line 71 is disposed at the second distal portion (front end side) with respect to the direction perpendicular to the axis AL of the inflator assembly 30, which is the deployment direction of the airbag 40. The fold line 71 is arranged to be inclined with respect to the axis AL. In the portion 63, as indicated by the arrow in FIG. 12A, the portion (hereinafter referred to as the folded portion 72) of the second distal portion (obliquely left lower side in FIG. 12A ) except the fold line 71 is folded back toward the vehicle inner side (front side of FIG. 12A ). By folding back the portion, the folded portion 72 is overlapped with a portion (hereinafter referred to as folded portion 73) enclosed by the fold line 71, the fold line 42 and the fold line 61 in portion 63. In the airbag 40, as illustrated in FIGS. 13A and 13B, the folded portions 69, 68, 66, 73, and 72 are superposed with each other toward the vehicle inner side from the vehicle outer side.As illustrated in FIGS. 13A and 13B, the fold lines 74 parallel to the fold line 42 (axis AL) are arranged at a plurality of portions in a region Z 1 of the second distal portion (front end side) except the partition 50 (outer connection portion 52) of the airbag 40 of the intermediate shape with respect to the direction perpendicular to the axis AL of the inflator assembly 30. The region Z 1 is folded toward the second proximal portion (rear end side) from the second distal portion (front end side) by a roll fold manner that repeatedly folds the region in the same direction along each fold line 74. By the folding, the airbag 40 is folded as shown in FIGS. 14A and 14B.As illustrated in FIGS. 14A and 14B, the fold lines 75 parallel to the fold line 42 (axis AL) are arranged at a plurality of portions in an area Z 2 of the second proximal portion (rear end side) except the partition 50 (outer connection portion 52) of the airbag 40 that is roll-folded with respect to the direction perpendicular to the axis AL. The region Z 2 is folded toward the second proximal portion (rear end side) from the second distal portion (front end side) by a bellows fold manner that alternately changes the fold-back direction along each fold line 75. By the folding, the airbag 40 is formed in the storage shape as shown in FIGS. 15A and 15B.The airbag module AM of the storage shape formed by folding the airbag 40 is of reduced size in the direction (substantially horizontal direction) perpendicular to the direction (substantially vertical direction) with respect to the axis AL of the inflator assembly 30, and is therefore suitable for accommodation in the narrow accommodation portion 21 of the seat back 14.In the airbag module AM of the storage shape, as shown in FIG. 4, the bolt 34 extending from the case 32 and inserted into the airbag 40 (fabric portion 43) is inserted into the side frame portion 17. Since the nut 35 is fastened to the bolt 34, the inflator assembly 30 is fastened to the side frame portion 17 together with the airbag 40.In this case, the inflator assembly 30 may be fixed to the side frame portion 17 by a member different from the bolt 34 and the nut 34 described above.As illustrated in FIG. 1, the side airbag device includes an impact sensor 81 and a control device 82 in addition to the above-described airbag module AM (see FIG. 2 ). The impact sensor 81 includes an acceleration sensor or the like, and is installed on the side wall 11 of the vehicle 10 (see FIG. 2 ) or the like to detect the impact applied to the side wall 11 from the side. The controller 82 controls the operation of the inflator 31 in response to the signal detected by the impact sensor 81.Although the vehicle 10 is provided with a seat belt device for restraining the occupant P seated in the vehicle seat 12 in the vehicle seat 12, such a seat belt device is not shown in FIG. 1 or the like.Next, the operation of the side airbag device including the configuration according to this embodiment will be described.According to the side airbag device, when no impact is applied to the side wall 11 of the vehicle 10 from the lateral direction due to the side collision or the like, no operation signal is output from the control device 82 to the inflator 31 to operate the inflator 31, and therefore no inflation gas is supplied from the inflator 31 to the airbag 40. The airbag module AM is still accommodated in the accommodation portion 21 as the storage shape (see FIG. 4 ).When an impact of a given or larger value is applied to the side wall 11 from the lateral direction due to the side collision or the like during traveling of the vehicle and then detected by the impact sensor 81, an operation signal is output from the controller 82 to the inflator 31 to operate the inflator 31 in response to the detected signal. In response to the operation signal, a gas generating agent generates the high-pressure inflation gas in the gas generator 31 and then the inflation gas is discharged therefrom. The discharged inflation gas is supplied to the airbag 40 through the communication portion of the container 32. Here, the airbag 40 is partitioned into the rear inflation chamber 46 and the front inflation chamber 47 by the partition 50 provided at the central portion in the longitudinal direction thereof, and the inflator assembly 30 is disposed at the lower portion of the inner rear end of the rear inflation chamber 46. For this reason, the inflation gas from the inflator 31 is supplied to the lower portion of the inner rear end of the rear inflation chamber 46. As illustrated in FIG. 17, the inflation gas in the rear inflation chamber 46 flows from the folded portion 73 adjacent to the inflator assembly 30 toward the folded portions 68 and 72 away from the inflator assembly. Also, the inflation gas in the rear inflation chamber 46 flows forward from the second proximal portion folded portion 73 (rear end side) toward the second distal portion folded portion 72 (front end side) with respect to the deploying direction. The folded portion 73 of the first proximal portion and the second proximal portion is the folded portion in which the inflator assembly 30 is accommodated.When the inflation gas flowing from the second proximal portion toward the second distal portion folded portion 72 arrives at the partition 50, the flow direction turns upward along the partition 50, and the inflation gas then joins the inflation gas flowing upward from the beginning.By the filling gas flowing upward, the rear filling chamber 46 is filled while being sequentially unfolded (deployed) from the bottom upward.Also, by the inflation gas flowing forward, the bellows-folded portion Z 2 (see FIGS. 14A and 14B ) of the airbag 40 behind the partition 50 is inflated while being sequentially unfolded (deployed) from the rear to the front.As described above, when the airbag 40 is deployed and inflated upward and forward, the seat pad 18 of the seat back 14 is pushed by the airbag 40, and therefore the breakable portion 23 in FIG. 4 is broken. As illustrated in FIG. 16, the airbag 40 jumps out of the seat back 14 in the substantially forward direction of the vehicle 10 in a state where the rear end of the airbag 40 remains in the accommodation portion 21 together with the inflator assembly 30.The inflation gas inflates the portion (behind the partition 50) of the distal portion folded portion 72 (front end side).Bellows folding is characterized in that the folded state is easily released. For this reason, the bellows-folded region Z 2 behind the partition 50 is rapidly deployed and filled forward.The volume of the rear inflation chamber 46 is smaller than that of the airbag 40 in the case where the airbag 40 is not partitioned by the partition 50. Also, the inflation thickness of the rear inflation chamber 46 with respect to the vehicle transverse direction is smaller than that of the airbag 40 in the vehicle transverse direction in the case where the airbag 40 is not partitioned. For this reason, the rear filling chamber 46 is easily deployed and filled while passing through the narrow space.As illustrated in FIGS. 7 and 17, a part of the inflation gas that flows upward in the rear inflation chamber 46 and arrives at the rear portion side of the chest region PT of the occupant P flows downward through the lower communication hole 55 in the front inflation chamber 47. Also, a part of the inflation gas that flows upward in the rear inflation chamber 46 above the lower communication hole 55 without passing through the lower communication hole 55 and arrives at the rear portion side of the head PH of the occupant P flows upward through the upper communication hole 54 in the front inflation chamber 47. In this case, since the opening area of the lower communication hole 55 is larger than that of the upper communication hole 54, the inflation gas flows through the lower communication hole 55 in an amount larger than that of the inflation gas flowing through the upper communication hole 54.A part of the inflation gas flowing into the front inflation chamber 47 through the lower communication hole 55 turns up and down. Also, a part of the inflation gas flowing into the front inflation chamber 47 through the upper communication hole 54 turns downward.By the inflation gas, the roll-folded portion before the partition 50 is deployed and inflated forward on the front portion side of the chest region PT or the head PH. In this case, as described above, since the flow rate of the inflation gas through the lower communication hole 55 and the upper communication hole 54 is different, the portion to be deployed and inflated on the front portion side of the head PH is deployed and inflated hardly earlier than other portions, particularly the chest region PT side, i.e., is deployed and inflated hardly early before passing the portion of the narrow clearance between the shoulder PS of the occupant P and the side wall 11 of the vehicle. The portion to be deployed and filled on the front portion side of the head PH is deployed and filled after passing the portion of the narrow space between the shoulder PS and the side wall 11. As a result, since the portion of the airbag 40 to be deployed and inflated on the side of the head PH can hardly pass the portion of the narrow space, a phenomenon of interfering with deployment and inflation of other portions hardly occurs. The airbag 40 is deployed and inflated on the side of the region extending from the chest region PT to the head PH of the occupant P.Also, the roll folding is characterized in that the folded portion is easily unfolded or deployed along the side wall 11 of the vehicle. For this reason, the roll-folded portion is deployed and filled forward before the partition 50 along the side wall 11 of the vehicle on the side of the front portion of the chest region PT or the head PH of the occupant P.When the inflation gas flowing into the front inflation chamber 47 through the lower communication hole 55 turns in the downward direction and then is supplied to the portion (before the partition 50) of the folded portion 72 of the second distal portion (front end side), the folded portion 72 folded back toward the vehicle inner side is unfolded (deployed). During the deploying, since the folded portion 72 does not come into contact with the side wall 11 of the vehicle, the unimpeded deploying is hardly interrupted due to the friction with the side wall 11, and also the portion (before the division 50) of the folded portion 72 is pushed by the portion behind the division 50 that starts to be filled early as described above, so that the deploying is performed quickly.When the inflation gas flowing upward in the rear inflation chamber 46 arrives at the first distal portion folded portion 68 (upper end side), the folded portion 68 folded back toward the vehicle inner side is unfolded (deployed). During the deploying, since the folded portion 68 does not come into contact with the side wall 11 of the vehicle 10, the unimpeded deploying is hardly interrupted due to the friction with the side wall 11.As illustrated in FIG. 7, when the airbag 40 is fully deployed and inflated, the front end 40 awhich is the head PH side of the occupant P is positioned in front of the front end 40 bwhich is the chest region PT side. For this reason, the area of the airbag 40 deployed and inflated on the side of the head PH is widened forward as compared with the area positioned at the same portion as the front end 40 bof the airbag 40 or positioned behind the front end 40 b.However, when the upper communication hole 54 is positioned at the folded portion other than the uppermost folded portion 68, for example, the folded portion 69, the inflation gas flows into the front inflation chamber 47 through the upper communication hole 54 to fill the front inflation chamber 47, which may stop the unfolding and inflation of the folded portion 68 that is performed later.In view of this, in this embodiment, since the upper communication hole 54 is positioned at the uppermost folded portion 68, the inflation gas in the rear inflation chamber 46 flows into the front inflation chamber 47 through the upper communication hole 54 in the process in which the folded portion 68 is deployed. Therefore, the unfolding and filling of the folded portion 68 is hardly interrupted due to the upper communication hole 54.The airbag 40 deployed and inflated as described above is sandwiched between the occupant P and the side wall 11 moving toward the vehicle inner side as indicated by the broken / two-dot lines in FIGS. 2 and 3, thereby directly pushing and restraining the occupant P toward the vehicle inner side and, at the same time, suppressing the impact applied to the occupant P from the lateral direction by the side wall 11.In this case, the inflation gas that flows into the upper portion of the front inflation chamber 47 through the upper communication hole 54 and turns downward is discharged to the outside (outside of the vehicle except the fabric portion 44) of the airbag 40 through the vent hole 56. Since the internal pressure is reduced by the discharge of the inflation gas, the shock applied to the occupant P from the lateral direction by the side wall 11 is alleviated. Also, since the inflation gas deploying and filling the upper portion of the front inflation chamber 47 as described above is discharged from the vent hole 56, the inflation gas is prevented from flowing to the lower portion of the front inflation chamber 47 located below the vent hole 56. As a result, the lower portion of the front inflation chamber 47 is prevented from being deployed and inflated due to the excessive pressure applied from the lateral direction of the chest region PT.According to the above-described embodiment, the effects given below are obtained.(1) In the side airbag device that can deploy and fill the airbag 40 between the side wall 11 of the vehicle 10 and the region extending from the chest region PT to the head PH of the occupant P seated in the vehicle seat 12 by the inflation gas discharged from the inflator 31, the distal portion folded portions 68 and 72 are folded back toward the vehicle inner side with respect to the deployment direction of the airbag 40 (see FIGS. 12A and 12B ).For this reason, the folded portions 68 and 72 are prevented from coming into contact with the side wall 11 of the vehicle 10 when the folded portions are released (deployed) from the folded-back state, thereby freely unfolding the folded portions 68 and 72.(2) The airbag 40 is folded from top to bottom so that the plurality of folded portions 66, 68, 69, and 73 are formed so that the deployment and the inflation are performed from bottom to top (see FIG. 17 ). And the folded portion 68 of the upper end of the airbag 40 is folded back toward the vehicle inner side as the folded portion of the distal portion having the deployment direction (see FIGS. 11A and 11B ).For this reason, since the folded portion 68 of the upper end of the airbag 40 is folded back toward the vehicle inner side, the effect of the above (1) can be obtained.(3) The airbag 40 is divided into the front inflation chamber 47 before the partition 50 and the rear inflation chamber 46 behind the partition 50 by the partition 50 extending in the substantially vertical direction, and the inflator 31 is disposed at the lower portion of the rear inflation chamber 46. The partition 50 is provided with the upper communication hole 54 for communicating rear inflation chamber 46 and front inflation chamber 47 at the portion that is the head PH side of the occupant P, and provided with the lower communication hole 55 for communicating rear inflation chamber 46 and front inflation chamber 47 at the portion that is the chest region PT side of the occupant P (see FIG. 7 ). Of the plurality of folded portions 66, 68, 69, and 73 formed by folding the airbag 40 from top to bottom, the region Z 1 before the partition 50 is folded by the front-rear roll folding (see FIGS. 13A and 13B ), and the region Z 2 behind the partition 50 is folded by the front-rear bellows folding (see FIGS. 14A and 14B ).For this reason, the bellows-folded portion behind the partition 50 can be deployed and filled rapidly forward from the side of the rear portion of the chest region PT or the head PH of the occupant P, thereby quickly restraining and protecting the region of the occupant P. Also, the roll-folded portion before the partition 50 along the side wall 11 of the vehicle can be deployed and filled forward from the front portion side of the chest region PT or the head PH of the occupant P, thereby correctly restraining and protecting the region of the occupant P.(4) The lower portion of the airbag 40 is folded from front to rear so as to form the folded portions 72 and 73 so that the deployment and the inflation are performed from rear to front. The folded portion 72 of the lower front end of the airbag 40 is folded back toward the vehicle inner side as the folded portion of the distal portion with respect to the deployment direction (see FIG. 12A ).For this reason, since the folded portion 72 of the lower front end of the airbag 40 is folded back toward the vehicle inner side, the effect of the above (1) can be obtained.(5) The airbag 40 is divided into the front inflation chamber 47 before the partition 50 and the rear inflation chamber 46 behind the partition 50 by the partition 50 extending in the substantially vertical direction, and the inflator 31 is disposed at the lower portion of the rear inflation chamber 46. The partition 50 is provided with the lower communication hole 55 for communicating the rear inflation chamber 46 and the front inflation chamber 47 at the portion that is the chest region PT side of the occupant P (see FIG. 7 ). Further, the folded portion 72 of the lower front end of the airbag 40 is folded back (outer connecting portion 52) in the state where the folded portion crosses the partition 50 (see FIG. 12A ).For this reason, the portion (before the partition 50) of the lower front end folded portion 72 can be pushed by the portion behind the partition which starts to be filled first, thereby performing the deployment quickly.The embodiment may be modified as indicated below.The opening area of the lower communication hole 55 may be set equal to that of the upper communication hole 54. In this case, the same effect as that of the embodiment is obtained.The vent hole 56 may be formed in other shapes than the circle, for example, a slit shape.The inflator 31 may be directly attached to the side frame 17 without using the container or the receiver 32.The almost entire part of the airbag 40 may be inflated as in the embodiment, but the airbag 40 may be provided with an non-inflation portion that is not supplied with the inflation gas and is therefore not inflated.In FIG. 10A, a portion of the first distal side (upper end) folded portion 68 may be further folded back toward the vehicle inner side. FIG. 18 shows an example thereof. In this case, for example, a fold line 77 parallel to the fold line 67 is disposed at the portion of the folded portion 68 in FIG. 10A spaced apart from the fold line 67 toward the first distal side (upper side of FIG. 10A ). In the portion 68, as illustrated in FIG. 10A, the portion (hereinafter referred to as a folded portion 78) of the first distal side (upper side of FIG. 10A ) except the fold line 77 is folded back toward the vehicle inner side (rear side of FIG. 10A ) along the fold line 77. By folding back the portion, most of the portion 68 is overlapped with a part (hereinafter referred to as a folded portion 79) of the airbag 40 which is pinched between the fold line 67 and the fold line 77.In this case, when the folded portion 78 positioned on the first distal side (upper end side) is filled while the state of being folded back to the vehicle inner side is released, the folded portion 68 does not come into contact with the side wall 11 of the vehicle, and therefore, the disruption of the unimpeded deployment due to the friction with the side wall 11 hardly occurs.The lower portion of the airbag 40 may be folded twice or more from front to back, forming three or more folded portions.Like the lower portion of the airbag 40, the folding from the second distal side (front end side) of the airbag 40 to the second proximal side (rear end side) may be performed at the upper portion including the lower portion.The folding from the first distal side (upper end side) of the airbag 40 to the proximal side (lower end side) or the folding from the second distal side (front end side) to the second proximal side (rear end side) may be omitted.The partition 50 may be formed of a fabric partition.Instead of the seat back 14 of the vehicle seat 12, the side wall 11 may be provided with a portion corresponding to the accommodation portion 21, and the airbag module AM may be inserted therein.Vehicles for which the side airbag device is used include various commercial vehicles used for transportation to private vehicles.

Claims

A side airbag device comprising: an inflator (31) disposed in a vicinity of a side of a chest region (PT) of an occupant (P) seated in a vehicle seat (12) to expel inflation gas in response to an impact applied from a lateral direction of a vehicle (10); and an airbag (40) accommodated in a folded state in which folded portions (66,68,69,72,73) are formed and deployed and inflated by the inflation gas from the inflator (31) between a region extending from the chest region (PT) to the head (PH) of the occupant (P) and a side wall (11) of the vehicle (10), wherein a folded portion (68) of a distal side of the airbag (40) is folded back toward the vehicle inner side with respect to a direction along an axis (AL) of the inflator (31), at least a portion of the airbag (40) is folded back from the top to the bottom to form folded portions (66, 68, 69) so as to be deployed and filled from the bottom to the top, and a folded portion (68) at an upper end of the airbag (40) is folded back toward the vehicle inner side as the folded portion (68) of the distal side with respect to the direction along the axis (AL) of the inflator (31).The side airbag device according to claim 1, wherein the airbag (40) is divided into a front inflation chamber (47) before the division (50) and a rear inflation chamber (46) behind the division (50) by a partition (50) extending in a substantially vertical direction, the inflator (31) is disposed at a lower portion of the rear inflation chamber (46), the partition (50) is provided with an upper communication hole (54) for communicating the rear inflation chamber (46) and the front inflation chamber (47) at a portion that is a side of the head (PH) of the occupant (P), the partition (50) is provided with a lower communication hole (55) for communicating the rear inflation chamber (46) and the front inflation chamber (47) at a portion, In addition, in the case where the first portion is the first portion of the chest portion (PT) of the occupant (P), and a portion (Z 1) of the airbag (40) that is folded from top to bottom and that is located in front of the partition (50) is folded from front to back by a roll fold manner that folds the portion (Z 1) repeatedly in a same direction, and a portion (Z 2) of the airbag (40) that is folded from top to bottom and that is located behind the partition (50) is folded from front to back by a bellows fold manner that changes the fold-back direction alternately.The side airbag device according to claim 1 or 2, wherein at least a lower portion of the airbag (40) is folded from front to rear so as to form folded portions (72, 73) deployed and inflated from rear to front, and a folded portion (72) of a lower front end of the airbag (40) is folded back toward the vehicle inner side as a folded portion (72) of a distal side of the airbag (40) with respect to a deployment direction.The side airbag device according to claim 3, wherein the airbag (40) is divided into a front inflation chamber (47) before the division (50) and a rear inflation chamber (46) behind the division (50) by a partition (50) extending in a substantially vertical direction, the inflator (31) is disposed at a lower portion of the rear inflation chamber (46), the partition (50) is provided with a lower communication hole (55) for communicating the rear inflation chamber (46) and the front inflation chamber (47) at a portion that is a chest region (PT) side of the occupant (P), and the folded portion (72) of the lower front end of the airbag (40) is folded back while crossing the partition (50).

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