Vehicle side airbag apparatus

A vehicle side airbag apparatus includes a resin seat frame that includes a recess that is elongated in a vehicle top-bottom direction, and that opens to a vehicle front side; a module casing that is disposed inside the recess and includes an outer side wall and an inner side wall that are arranged in parallel with each other, and extend in the vehicle front-rear direction, the outer side wall being disposed outside the inner side wall in a vehicle width direction, in a horizontal sectional view; and a side airbag stored in a folded manner within the module casing. In at least one of the outer side wall and the inner side wall, a low rigidity portion is provided in an area including an entirety of, or a portion of a region that overlaps with an iliac crest of a seated occupant in a side view.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2011-014550 filed on Jan. 26, 2011 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a vehicle side airbag apparatus.

2. Description of Related Art

Japanese Patent No. 3805404 describes a structure in which a rear seat side airbag apparatus is provided inside each of seat side portions that are arranged on both sides of a split-folding seatback and are fixed to a vehicle body.

However, in the related art described above, if a seat frame that is disposed inside the seat side portion is made of resin, it is required to prevent the seat frame from breaking or flying in the event of a side collision. It is conceivable to use a metal casing as a casing that accommodates the airbag. However, if the metal casing is used, there is a possibility that a portion of the casing comes into contact with a lumbar region (iliac position) of a seated occupant through a seat frame or a seat pad in the event of the side collision. Therefore, the related art described above leaves room for improvement.

SUMMARY OF THE INVENTION

The invention provides a vehicle side airbag apparatus in which a seat frame is effectively prevented from flying in the event of a side collision when the seat frame is made of resin, and which reduces load input to the lumbar region of a seated occupant.

A vehicle side airbag apparatus according to an aspect of the invention includes: a seat frame that is made of resin and supports a pad disposed inside a side portion of a seatback, wherein the seat frame includes a recess that is elongated in a top-bottom direction of a vehicle, and that opens to a vehicle front side; a module casing that is disposed inside the recess and includes a pair of an outer side wall and an inner side wall, wherein the outer side wall and the inner side wall are arranged in parallel with each other, and extend in a front-rear direction of the vehicle, and the outer side wall is disposed outside the inner side wall in a width direction of the vehicle, in a horizontal sectional view; and a side airbag that is stored in a folded manner within the module casing, wherein when gas produced by an inflator is supplied to the side airbag, the side airbag is deployed along a surface of a side portion of a vehicle body, the surface facing an inside of a vehicle cabin. In at least one of the outer side wall and the inner side wall in the module casing, a low rigidity portion is provided in an area including an entirety of, or a portion of a region that overlaps with an iliac crest of a seated occupant in a side view.

In the vehicle side airbag apparatus according to the aspect described above, the low rigidity portion may be provided in the entirety of, or a portion of the region that overlaps with the iliac crest of the seated occupant in the side view. In addition, the module casing may be made of metal.

According to the aspect described above, the pad that is disposed inside the side portion of the seatback is supported by the seat frame that is made of resin. The seat frame includes the recess that is elongated in the top-bottom direction of the vehicle and opens to the vehicle front side, and the metal module casing is disposed inside the recess. Accordingly, the seat frame is effectively prevented from, for example, flying in the event of the side collision.

If the side portion of the vehicle body enters a vehicle cabin in the event of the side collision, the side wall of the module casing may move close to a lumber region of an occupant. In this case, according to the above aspect of the invention, load input to the lumbar region of the seated occupant is reduced, because the low rigidity portion is provided in the area including the entirety of, or a portion of the region that overlaps with the iliac crest of the seated occupant in the side view, in at least one of the outer side wall and the inner side wall in the module casing.

In the vehicle side airbag apparatus according to the aspect described above, length of the outer side wall in the front-rear direction of the vehicle may be longer than length of the inner side wall in the front-rear direction of the vehicle, and an indentation may be formed in the outer side wall as the low rigidity portion. In the vehicle side airbag apparatus according to the aspect described above, length of the outer side wall in the front-rear direction of the vehicle may be longer than length of the inner side wall in the front-rear direction of the vehicle, and a fragile portion may be provided in the outer side wall as the low rigidity portion.

According to the aspect of the invention, the length, in the vehicle front-rear direction, of the outer side wall disposed on the outer side in the vehicle width direction is longer than the length, in the vehicle front-rear direction, of the inner side wall disposed on the inner side in the vehicle width direction. Therefore, there is a high possibility that the outer side wall moves close to the lumbar region of the seated occupant. However, according to the aspect of the invention, since the indentation or the fragile portion is provided in the outer side wall as the low rigidity portion, if the outer side wall moves close to the lumbar region of the seated occupant, the indentation or the fragile portion becomes adjacent to the lumbar region of the seated occupant.

As described above, the vehicle side airbag apparatus according to the aspect of the invention has excellent advantageous effects of effectively preventing the seat frame from flying in the event of the side collision when the seat frame is made of resin, and reducing load input to the lumbar region of the seated occupant.

The vehicle side airbag apparatus according to the aspect of the invention has the excellent advantageous effect of further reducing the possibility that large load is transferred to the lumbar region of the seated occupant.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, a vehicle side airbag apparatus according to an embodiment of the invention will be described with reference toFIG. 1throughFIG. 5. In the drawings, an arrow FR denotes a vehicle front side, an arrow UP denotes a vehicle upper side, and an arrow IN denotes an inner side in a width direction of a vehicle (vehicle width direction), as appropriate.

As shown inFIG. 1andFIG. 3, a rear seat side airbag apparatus10as the vehicle side airbag apparatus according to the embodiment is applied to a rear seat12, and the rear seat12includes a rear seat cushion14that supports the buttocks and the femoral region of an occupant, and a rear seatback16that supports the lumbar region and the back of the occupant. Depending on vehicle models, a head restraint is provided on an upper end of the rear seatback16.

The rear seatback16is a split-folding rear seatback and includes paired right and left main portions24that can recline or fold with respect to a rear floor21, and paired right and left side supports26. Each of the right and left side supports26is disposed on an outer side of the main portion24in the vehicle width direction, that is, disposed closer to a door of the vehicle than the main portion24is. Here, the side support26may be regarded as the “side portion of the seatback” according to the invention.

The paired right and left side supports26are respectively fixed to side walls of a vehicle body. Each side support26includes a pad30that has a substantially curved sectional shape. A surface of the pad30is covered by a cover32. In addition, a resin seat frame28is disposed on a reverse side of the pad30. The seat frame28is elongated in a height direction of the seatback (seatback height direction), and its horizontal sectional shape is a substantially U-shape that is open toward the vehicle rear side. The pad30is supported by the seat frame28.

As shown inFIG. 3, the seat frame28includes a recess36that is dented toward the vehicle rear side, and that has a substantially rectangular parallelepiped shape. The recess36extends from a substantially center position to an inner position in the seat frame28in the vehicle width direction. An airbag module38that constitutes the main portion of the rear seat side airbag apparatus10is mounted in the recess36.

The airbag module38includes a metal module casing40(seeFIG. 2andFIG. 4) that is mounted inside the recess36, a side airbag42that is stored in a folded manner in the module casing40, an inflator44in a circular cylindrical shape as gas generating means that generates gas inside the side airbag42in the event of the side collision, and a diffuser (not shown) as flow regulating means that surrounds the inflator44.

As shown inFIG. 2throughFIG. 4, the module casing40has a substantially box shape that is elongated in the seatback height direction, and the module casing40is disposed in a manner such that an opening portion of the module casing40faces toward the vehicle front side. In addition, the module casing40includes a bottom wall40A that is a substantially rectangular flat plate; a pair of an outer side wall40B and an inner side wall40C that extend from side portions of the bottom wall40A in a front-rear direction of the vehicle (vehicle front-rear direction), and that are arranged in substantially parallel with each other; and an upper wall40D and a lower wall40E that extend from an upper edge and a lower edge of the bottom wall40A in substantially parallel with each other. The outer side wall40B is a side wall that is disposed on the outer side in the vehicle width direction (i.e., the outer side wall40B is disposed outside the inner side wall40C in the vehicle width direction), and the inner side wall40C is a side wall that is disposed on the inner side in the vehicle width direction (i.e., the inner side wall40C is disposed inside the outer side wall40B in the vehicle width direction).

The side airbag42is folded in a predetermined folding manner (in this embodiment, the side airbag42is accordion-folded) and covered with a wrapping material (not shown) so that the shape is maintained. The wrapping material easily breaks when the side airbag42is inflated and deployed. In general, the airbag may be rolled-up, or may be accordion-folded. In this embodiment, the side airbag42is accordion-folded so that the side airbag42is easily unfolded. However, the airbag may be rolled-up, or a portion of the airbag may be rolled-up and a portion of the airbag may be accordion-folded.

On the other hand, referring back toFIG. 1, the inflator44and the diffuser are disposed inside the folded side airbag42. The inflator44is arranged such that a longitudinal direction of the inflator44is a top-bottom direction of the side support26(seatback height direction). A gas injection portion48that is provided with a plurality of gas injection holes is formed to protrude at one end (at the lower end) of the inflator44in the longitudinal direction. In addition, a squib that is an ignition device, and an igniting agent are disposed at the other end (at the upper end) of the inflator44in the longitudinal direction. The squib is electrically connected to an airbag ECU that is disposed, for example, below a console box, and the airbag ECU is electrically connected to a side collision sensor that is disposed in a side portion of the vehicle body. When the side collision sensor detects a side collision of the vehicle, the side collision sensor outputs a detection signal to the airbag ECU. The airbag ECU determines whether the side airbag42needs to be actuated or not, and once the airbag ECU determines that the side airbag needs to be actuated, a predetermined current is applied to the squib, and the igniting agent is ignited. Accordingly, the gas is discharged from the plurality of gas injection holes provided in the inflator44. Instead of the inflator44that contains the gas-forming agent, an inflator that contains a high-pressure gas may be used.

The aforementioned inflator44is covered by the diffuser (not shown) that functions as the flow regulating means. The diffuser is fixed to the inflator44by swaging or the like. The diffuser regulates the flow of the gas that is discharged from the inflator44and supplies it into the side airbag42. Paired upper and lower stud bolts are disposed in the diffuser. The upper stud bolt extends through the side airbag42, the bottom wall40A of the module casing40, and a bottom wall portion36A of the recess36(seeFIG. 3), and a distal end of the stud bolt is screwed with a nut. Accordingly, the upper portion of the diffuser is fastened and fixed to the seat frame28together with the module casing40, and the side airbag42is interposed between the diffuser and the bottom wall40A of the module casing40. An area of the airbag module38, which is located at a height at which the inflator44is disposed, is fastened and fixed to the seat frame28.

The lower stud bolt that is disposed in the diffuser extends through the side airbag42and the bottom wall40A of the module casing40, and a distal end of the stud bolt is screwed with a nut. Accordingly, the lower portion of the diffuser is fastened and fixed to the module casing40, and the side airbag42is interposed between the diffuser and the bottom wall40A of the module casing40.

As shown inFIG. 1, the side airbag42includes in one unit: a lumbar protection bag portion56that is deployed between the lumbar region of the seated occupant P and a door trim of a rear side door that is a side portion of the vehicle body; and a chest/shoulder protection bag portion58that is deployed between the chest and the shoulder of the seated occupant P and the door trim of the rear side door that is the side portion of the vehicle body. Thus, the side airbag42according to the embodiment is configured as a side airbag that is large in a top-bottom direction of the vehicle (vehicle top-bottom direction).

As shown inFIG. 3andFIG. 4, in the aforementioned module casing40, the length, in the vehicle front-rear direction, of the outer side wall40B disposed on the outer side in the vehicle width direction is longer than the length, in the vehicle front-rear direction, of the inner side wall40C disposed on the inner side in the vehicle width direction. That is, as shown inFIG. 3, dimensions of the side walls are set such that the length h1of the outer side wall40B is longer than the length h2of the inner side wall40C (h1>h2).

In addition, as shown inFIG. 2, in the outer side wall40B, an indentation60is formed as a low rigidity portion in an area including a region that overlaps with an iliac crest Q of the seated occupant P in a side view. By forming the indentation60, the rigidity of this area of the outer side wall40B is lower than the rigidity of the rest of the outer side wall40B. In consideration of differences in physical constitutions of seated occupants P, the width of the indentation60in the vehicle top-bottom direction is wider than the width of the iliac crest Q in the vehicle top-bottom direction. In this embodiment, in the outer side wall40B, the indentation60is formed in the area including the entirety of the region that overlaps with the iliac crest Q of the seated occupant P in the side view (precisely, the indentation60is formed in the area that is wider in the seatback height direction than the entire region that overlaps with the iliac crest Q in the side view). However, the invention is not limited to the above configuration. The indentation may be formed in the entirety of the region that overlaps with the iliac crest Q in the side view, the indentation may be formed in an area including a portion of the region that overlaps with the iliac crest Q in the side view, or the indentation may be formed in a portion of the region that overlaps with the iliac crest Q in the side view. In these cases as well, the effect of reducing the rigidity is obtained in accordance with the area (region) in which the indentation is formed.

Next, functions and effects of the embodiment will be described. The rear seat side airbag apparatus10according to the embodiment detects a vehicle side collision using the side collision sensor (not shown) that is disposed on the side portion of the vehicle body such as a center pillar or a rear pillar, in the event of the vehicle side collision. The detection signal is output from the side collision sensor to the airbag ECU, and the airbag ECU determines that the rear seat side airbag apparatus10needs to be actuated. Therefore, the airbag ECU actuates the inflator44. That is, the predetermined current is applied to the squib of the inflator44. Accordingly, the inflator44produces a large amount of gas to inflate the side airbag42that is stored in a folded manner within the module casing40. Thus, the cover32breaks along a specified burst line, and an opening is formed in a front portion of the side support26. As a result, as shown inFIG. 1andFIG. 3, the side airbag42is inflated and deployed between the side portion of the upper body of the seated occupant P and the door trim of the rear side door. More specifically, the lumbar protection bag portion56is deployed between the lumbar region of the seated occupant P and the door trim. The chest/shoulder protection bag portion58is also deployed between the chest and the shoulder of the seated occupant P and the door trim. As a result, the occupant is protected against an impact by the side airbag42in the event of the side collision. In other words, the side airbag42is deployed along a surface of the side portion of the vehicle body, the surface facing the inside of a vehicle cabin.

In the embodiment, the pad30that is disposed inside the side support26is supported by the resin seat frame28. The seat frame28includes the recess36that is elongated in the vehicle top-bottom direction, and that opens to the vehicle front side. The metal module casing40is disposed inside the recess36. Accordingly, the seat frame28is effectively prevented from, for example, flying in the event of the side collision.

If the side portion of the vehicle body enters the vehicle cabin in the event of the side collision, the module casing40moves close to the seated occupant P due to the entry of the side portion of the vehicle body as shown by two-dot chain lines inFIG. 3. In this case, since the length of the outer side wall40B in the vehicle front-rear direction is longer than the length of the inner side wall40C in the vehicle front-rear direction in the module casing40according to the embodiment, the front portion of the outer side wall40B may be adjacent to the lumbar region of the seated occupant P. However, even in that case, since the outer side wall40B has the indentation60that is formed in the area including the region that overlaps with the iliac crest Q of the seated occupant P in the side view, load input to the lumbar region of the seated occupant P is reduced.

According to the rear seat side airbag apparatus10according to the embodiment as described above, when the seat frame28is made of resin, the seat frame28is effectively prevented from, for example, flying in the event of the side collision, and load input to the lumbar region of the seated occupant P is reduced.

Specifically, as in the embodiment, the length, in the vehicle front-rear direction, of the outer side wall40B disposed on the outer side in the vehicle width direction is longer than the length, in the vehicle front-Tear direction, of the inner side wall40C disposed on the inner side in the vehicle width direction (h1>h2). Therefore, there is a high possibility that the outer side wall40B moves close to the lumbar region of the seated occupant. However, according to the embodiment, since the indentation60is formed in the outer side wall40B, if the outer side wall40B moves close to the lumbar region of the seated occupant P, the indentation60becomes adjacent to the lumbar region of the seated occupant P. As a result, it is possible to further reduce the possibility that large load is transferred to the lumbar region of the seated occupant P.

Supplemental Description of the Embodiment

(1) In the embodiment described above, the vehicle side airbag apparatus according to the invention is applied to the rear seat side airbag apparatus10. However, the invention is not limited to the rear seat side airbag apparatus, and the invention may be applied to a front seat side airbag apparatus.

(2) In the embodiment described above, the configuration in which the side airbag42includes the lumbar protection bag portion56and the chest/shoulder support bag portion58has been described as an example. However, the invention is not limited to this configuration, and the invention may be applied to any of side airbags with other configurations for protection.

(3) In the embodiment described above, the indentation60is formed only in the outer side wall40B, and the indentation60is not formed in the inner side wall40C. However, the invention is not limited to this configuration, and the low rigidity portion may be provided only in the inner side wall, or the low rigidity portions may be provided in both of the outer side wall and the inner side wall. In other words, if the side wall that is pushed by the side portion of the vehicle body to move close to the iliac crest Q of the seated occupant P in the event of the side collision is the inner side wall, then the low rigidity portion needs to be formed in the inner side wall, and if both of the outer side wall and the inner side wall move close to the iliac crest Q, then the low rigidity portions need to be formed in both of the outer side wall and the inner side wall.

(4) The description in (4) relates to the description in above (3). In the embodiment, the length h1of the outer side wall40B is longer than the length h2of the inner side wall40C. However, the invention is not limited to this configuration, and the invention may include the structure in which the length of the inner side wall in the vehicle front-rear direction is longer than the length of the outer side wall in the vehicle front-rear direction, and the structure in which the lengths of both side walls in the vehicle front-rear direction are identical with each other.

(5) In the embodiment described above, the indentation60is formed in the outer side wall40B as the low rigidity portion. However, the invention is not limited to this configuration, and other configurations may be employed. For example, as shown inFIG. 5, fragile portions82that are slits extending in the vehicle front-rear direction may be formed respectively in two portions, that is, a lower end portion and a substantially middle portion in an outer side wall80A of a module casing80in the seatback height direction. By forming these fragile portions82, the rigidity of the lower portion of the outer side wall80A is reduced.