JP2005247001A - Airbag device for protecting knee - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag device for protecting knees which rapidly deploys an airbag upwardly while protruding it backward of a vehicle. <P>SOLUTION: In the airbag device for protecting knees, an airbag 45 stored in a case 11 push-opens an airbag cover 33 held in a case 11 while the airbag is inflated, and the airbag is deployed and inflated. An inflator 30 of a substantially disk shape has a plurality of gas discharge ports 30b on an outer circumferential surface thereof, and is mounted on and fixed to the position in a vicinity of a center in the right-to-left direction in case lower wall portion 14. The airbag 45 is fixed to the lower wall portion 14 while surrounding the inflator 30 in the case 11 over the entire circumference of a circumferential edge of a gas inlet to allow inflation gas to flow in. The center of gravity G near the center in the right-to-left direction when stored in the case is arranged on the rear upper side of the inflator 30, and the airbag is stored and held in the case 10 on the front side of the airbag cover 33. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  According to the present invention, an airbag that is folded and stored in a case disposed on the front lower side of a seated occupant's knee pushes and opens the airbag cover while being inflated by an inflation gas supplied from an inflator. The present invention relates to a knee protection airbag device configured to protrude from a case to the vehicle rear side and to expand and inflate upward.

Conventionally, in this type of knee protection airbag device, as an inflator for supplying inflation gas to the airbag, a substantially disk-shaped disk type is attached and fixed to the upper wall portion and the lower wall portion of the case peripheral wall portion. There was a thing to make (for example, refer patent document 1).
JP 2002-337651 A

  However, in the conventional airbag device for knee protection, there is no description about the folded and stored state of the airbag in the case, and while the airbag is in the initial stage of inflation, There was room for improvement in terms of rapid deployment toward the market.

  This invention solves the above-mentioned subject, and provides the airbag apparatus for knee protection which can be rapidly expanded upwards, making an airbag protrude toward the vehicle rear side. With the goal.

The airbag device for knee protection according to the present invention is inflated by an inflating gas supplied from an inflator while an airbag stored in a folded manner in a case disposed on the front lower side of a seated occupant's knee. As a configuration that pushes open the airbag cover held by the case, protrudes from the case to the vehicle rear side, and expands and inflates upward.
The case is configured to include a peripheral wall portion having a substantially rectangular tube shape in which the front end side is closed by the bottom wall portion and the rear end side is an opening for protruding the airbag and the axial direction is substantially along the front-rear direction. And
The inflator is a disk-type airbag device having a disk shape in which a plurality of gas discharge ports are disposed on the outer peripheral surface as a substantially disk shape,
The inflator is mounted and fixed by placing the gas outlet in the case at a position near the center in the left-right direction on the lower wall part facing the upper and lower sides of the case peripheral wall part,
The airbag cover is disposed at an inclination so that the upper side is positioned on the rear side and the lower side is positioned on the front side on the rear side of the opening of the case,
The airbag is fixed to the lower wall while surrounding the inflator inside the case, and the center of gravity near the center in the left-right direction when the case is stored after folding. It is characterized by being disposed in the rear upper side of the inflator and housed and held in a case on the front side of the airbag cover.

  In the airbag apparatus for knee protection according to the present invention, the airbag has a center of gravity near the center in the left-right direction when the case is stored after being folded, arranged at the upper rear side of the inflator so that the inside of the case on the front side of the airbag cover. It is the structure accommodated and hold | maintained. That is, in the knee protection airbag device according to the present invention, in the initial stage of inflation of the airbag, the inflation gas discharged from the gas discharge port of the inflator is located at the rear upper side near the center of gravity near the center in the left-right direction of the airbag. It becomes the aspect which extrudes toward. Therefore, the airbag pushes open the airbag cover, cancels the folding, protrudes toward the rear side of the vehicle, and easily expands upward.

  Further, in the knee protection airbag device of the present invention, the inflator is attached and fixed to the lower wall portion of the case peripheral wall portion with the gas discharge port disposed in the case, so that the inflation gas is supplied to the case. Inside, it is easy to discharge toward the rear upper side. Therefore, the inflating gas flowing inside the airbag protruding from the case can easily flow toward the rear upper side, and the aspect of the airbag expanding toward the upper side while protruding toward the rear side of the vehicle is promoted. It becomes.

  Furthermore, in the knee protection airbag device of the present invention, since the inflator is attached and fixed at a position near the center of the lower wall portion of the case peripheral wall portion in the left-right direction, the airbag is deployed in the left-right direction. Are also equalized and can be quickly deployed.

  Therefore, in the knee protection airbag device of the present invention, the airbag can be rapidly deployed upward while protruding toward the vehicle rear side.

  In the knee protection airbag device of the present invention, the airbag cover is disposed in an inclined manner so that the upper side is positioned on the rear side and the lower side is positioned on the front side. The center of gravity in the vicinity of the center in the left-right direction when the case is stored after the airbag is folded is easily arranged at a position on the upper rear side of the inflator.

Then, in the knee protection airbag device having the above-described configuration, the airbag is folded in a direction along the left-right direction at the upper end side when the inflation is completed, and is brought close to the gas inlet side, and when the inflation is completed. As a configuration that folds the left and right end sides by a longitudinal folding process in which the front and rear folds are made to approach the center side in the left and right direction,
It is preferable that the folded lump portion after the vertical folding step is stored in the left and right side portions around the inflator in the case.

  In such a configuration, the folded-up portion of the airbag can be stored in the left and right portions of the inflator, and the space in the case can be used effectively.

Further, in the knee protection airbag device configured as described above, the airbag cover may be attached to the case peripheral wall portion so as to absorb an assembly error with respect to the interior member around the airbag cover on the front side of the occupant. And movably assembled,
It is preferable that the assembly portion of the airbag cover with respect to the lower wall portion of the peripheral wall portion is assembled to the case using a fixing means for the inflator to the case.

  In the knee protection airbag device having the above configuration, the airbag cover is assembled to be movable with respect to the case peripheral wall so as to be able to absorb an assembly error with respect to the surrounding interior member. Thus, when the airbag device is mounted on the vehicle, even if the assembly error occurs with respect to the interior parts in which the airbag cover is disposed around, It can move with respect to the interior member so as to absorb the error and not cause a sense of incongruity with the interior member disposed around. Therefore, the design property seen from the vehicle inner side can be improved. Further, in the airbag device for knee protection with the above configuration, since the assembly portion of the airbag cover to the lower wall portion of the peripheral wall portion is assembled to the case using a fixing means to the case of the inflator, The number of locking claws for assembling the airbag cover to the case can be reduced, and the apparatus itself can be reduced in weight.

Further, in the airbag device for knee protection having the above configuration, the airbag cover includes:
The upper part of the case, which is the upper wall side, is movable with respect to the case so as to be able to absorb an assembly error with respect to the interior member around the airbag cover on the front side of the occupant. In addition to the configuration to be assembled,
It is good also as a structure which is made to fasten the lower part site | part used as a case lower wall part side with a case with an inflator.

  In the knee protection airbag device configured as described above, the upper portion of the airbag cover is movably assembled to the case so as to be able to absorb assembly errors with respect to surrounding interior members. Therefore, when the airbag device is mounted on a vehicle, even if an assembly error occurs with respect to the interior part in which the airbag cover is arranged around, the upper portion of the airbag cover The side part can be moved with respect to the interior member so as to absorb the generated assembly error and not cause a sense of incongruity with the interior member disposed around. Moreover, in the airbag apparatus for knee protection of the said structure, since the site | part of the lower side used as the case lower wall part side in an airbag cover is made to fasten together with a case with an inflator, an airbag cover is firmly fixed to a case. It can be attached and fixed to. In the above-described knee protection airbag device, the lower portion of the airbag cover is configured to be fastened together with the inflator so that it cannot move with respect to the case, but the lower portion of the airbag cover. Is disposed below the knees of the seated occupant, and is disposed at a position on the front side of the vehicle with respect to the upper portion, so that it is difficult for the occupant to see when viewed from the inside of the vehicle, Even if some assembling errors occur between the lower portion and the surrounding interior members, the design as viewed from the vehicle interior side is not greatly reduced.

Furthermore, in the knee protection airbag device having the above-described configuration, the airbag has a vehicle body side wall portion disposed on the vehicle body side and a passenger side wall portion disposed on the passenger side when the inflation is completed with substantially the same outer shape. As a plane airbag type formed by combining the outer peripheral edges of the vehicle body side and the occupant side wall,
The position of the gas inlet of the airbag is set so that the tension acting on the side wall of the vehicle body is greater than the tension acting on the side wall of the passenger and the upper end side of the airbag when inflation is completed is pulled toward the vehicle body side. It is preferable to set it as the structure set | placed in the position which leaves | separates from the upper end side of a passenger | crew side wall part along the surrounding wall of a bag.

  In the knee protection airbag device configured as described above, when the airbag is completely inflated, a larger tension is applied to the side wall of the vehicle body than to the side of the occupant side wall. That is, the expansion is completed by being pulled toward the interior member side. Therefore, it becomes easy to deploy and inflate the airbag along the surrounding interior member.

Furthermore, in the airbag device for knee protection with the above configuration, the airbag is configured to be attached to the case using an annular retainer disposed around the periphery of the gas inlet in the airbag.
The retainer is preferably configured to include a base that presses the periphery of the gas inlet, and a cover that can cover the gas discharge port of the inflator as a cylindrical shape that extends upward from the outer periphery of the base.

  In the knee protection airbag device configured as described above, the gas discharge port disposed in the inflator is covered by the cover portion of the retainer, so that the inflation gas discharged from the gas discharge port directly constitutes the airbag. It is possible to prevent the airbag from being damaged by the inflation gas without hitting the base fabric.

Furthermore, in the knee protection airbag device having the above-described configuration, the airbag is configured to be attached to the case using an annular retainer disposed around the periphery of the gas inlet in the airbag.
The retainer includes a base that presses the periphery of the gas inlet, and a plurality of bolts that extend downward from the base so as to pass through the case lower wall and are fixed to the case lower wall by being fastened with nuts. As composition
In the case lower wall, an insertion hole for inserting the bolt is arranged,
It is preferable that the insertion hole is formed to have an opening extending to the opening side of the airbag for projecting the airbag.

  In the knee protection airbag device having the above-described configuration, the insertion hole disposed in the case lower wall portion is formed with an opening extending toward the airbag protrusion opening side of the case. On the other hand, when attaching the airbag using the retainer, the lower end of the retainer bolt is inserted into the opening, and the bolt can be easily placed at a predetermined position on the front side. The work of inserting the retainer into the narrow case becomes easy, and the workability of attaching the airbag to the case is improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 11, the knee protecting airbag device S1 of the embodiment can protect the knee K (KL / KR) of the driver MD as an occupant on the front lower side of the knee K of the occupant MD. It is arranged below a certain steering column 2.

  In addition, the upper and lower sides, the left and right, and the front and rear in this specification correspond to the upper and lower, left and right, and front and rear of the vehicle when the knee protection airbag device S1 is mounted on the vehicle.

  As shown in FIG. 1, the steering column 2 includes a column main body 3 connected to the steering wheel 1 and a column cover 6 disposed so as to cover the column main body 3 below the steering wheel 1. Has been. The column main body 3 includes a main shaft 4 and a column tube 5 that covers the periphery of the main shaft 4.

  The column cover 6 is made of a synthetic resin having a substantially rectangular tube shape, and is disposed along the axial direction of the column body 3 so as to cover the column body 3. A rear surface 6a of a portion of the column cover 6 that protrudes from an instrument panel (hereinafter abbreviated as “instrument panel”) 8 has a substantially rectangular plate shape, and is formed in a curved shape that rises rearward in the vehicle front-rear direction.

  The knee protection airbag device S1 includes a folded airbag 45, an inflator 30 that supplies inflation gas to the airbag 45, a case 11 that houses the folded airbag 45 and opens the vehicle rear side, an airbag A retainer 23 for attaching the peripheral edge 48 of the gas inflow port 48 a in the bag 45 to the case 11, and an airbag cover 33 that covers the vehicle rear side of the opening 11 a in the case 11 are provided.

  As shown in FIGS. 2 and 3, the case 11 is made of sheet metal and is disposed on the lower side of the steering column 2 that is the front lower side of the knee K of the occupant MD. The case 11 includes a substantially rectangular tube-shaped peripheral wall portion 12 that is arranged with the axial direction approximately along the front-rear direction, and a bottom wall portion 21 that closes the front end side (the vehicle front side) of the peripheral wall portion 12. The rear end side (vehicle rear side) is configured as an opening 11a for protruding the airbag 45. The wall portions 13, 14 facing the upper and lower sides of the case peripheral wall portion 12 are formed with the rear end of the upper wall portion 13 positioned on the vehicle rear side with respect to the rear end of the lower wall portion 14. The opening surface 11a on the side is formed so that the upper side is positioned on the rear side and the lower side is positioned on the front side, and is inclined in accordance with a later-described lower panel 8b of the instrument panel 8 disposed around. Yes.

  As shown in FIG. 6, an insertion hole 16 for inserting a body part 30 a (described later) of the inflator 30 and four bolts 25 (described later) of the retainer 23 are inserted into the lower wall part 14 of the peripheral wall part 12. The insertion hole 17 is disposed. The insertion hole 16 is disposed in a substantially circular shape at a position near the center of the lower wall portion 14 in the left-right direction. In the case of the embodiment, each insertion hole 17 through which the bolt 25 is inserted has an opening 18 that extends to the opening 11 a side (vehicle rear side) of the case 11. In the case of the embodiment, the opening 18 is formed in a groove shape along the front-rear direction on both the left and right sides of the insertion hole 16 so as to connect the insertion holes 17, 17 disposed in the front-rear direction. ing. In the embodiment, each opening 18 (insertion hole 17) is formed to communicate with the insertion hole 16, respectively. Further, the opening 18 is formed so that the length dimension in the front-rear direction is larger than the inner diameter dimension of the insertion hole 16 so as to extend to both the front and rear sides.

  In addition, a plurality of locking claws 20 for assembling the airbag cover 33 to the case 11 protrude from the upper and lower walls 13 and 14 of the case peripheral wall 12. Four locking claws 20 are arranged in parallel in the left and right direction on the upper wall portion 13, and are arranged one by one at positions on the left and right sides of the insertion hole 16 in the lower wall portion 14. Each locking claw portion 20 is configured by bending the front end 20a side toward the vehicle front side, and the front end 20a side is a locking hole formed in upper and lower side wall portions 36 and 37 (to be described later) of the airbag cover 33. It is set as the structure which can be latched to the part 36a * 37a periphery. And each latching claw part 20 is an airbag which can move the airbag cover 33 with respect to the case surrounding wall part 12 in the state which latched the front-end | tip 20a to each latching hole part 36a * 37a periphery. The upper and lower side wall portions 36 and 37 of the cover 33 are assembled. In the case of the embodiment, each locking claw portion 20 is formed with a predetermined shape in the upper and lower wall portions 13 and 14 and is raised from the upper and lower wall portions 13 and 14 so that the upper and lower It is configured integrally with the wall portions 13 and 14 (see FIGS. 2 and 5).

  Furthermore, a mounting bracket 22 for mounting and fixing the case 11 to the body side is disposed at a portion of the case peripheral wall portion 12 that is the periphery of the opening 11a. In the case of the embodiment, the mounting brackets 22 are disposed at two positions near the upper end on both the left and right edges of the opening 11a (see FIGS. 4 and 5). These mounting brackets 22 are fixedly mounted on an instrument panel reinforcement (not shown) disposed on the vehicle body side. Of course, the arrangement position of the mounting bracket 22 is not limited to the left and right edges, and may be arranged on the upper edge or the lower edge of the opening 11a, for example. Further, the vehicle body side member for fixing the mounting bracket 22 is not limited to the instrument panel reinforcement. For example, a vehicle in which a rigid sheet metal knee panel is disposed on the vehicle front side of the lower panel 8b. In this case, the mounting bracket may be fixed to the body side by being fixed to the knee panel.

  The retainer 23 is formed of a sheet metal and has a substantially annular base portion 24 having a hole that opens substantially in the same shape as the insertion hole 16 of the case 11. The retainer 23 extends substantially upward from the outer peripheral edge of the base portion 24 toward the case upper wall portion 13. And a rectangular tube-shaped cover portion 26. The base 24 has an outer peripheral edge formed in a substantially square shape (substantially square shape), and bolts 25 (25A and 25B) extending downward are fixed to the four corner portions. Bolts 25 </ b> A and 25 </ b> A arranged on the vehicle front side (case bottom wall portion 21 side) are located below the attachment holes 48 b of the airbag 45 and the case peripheral wall portion 12 in a state where the retainer 23 is disposed in the airbag 45. The nut 27 is tightened by being inserted into the insertion hole 17 of the wall portion 14 and the mounting hole 30d provided in the flange portion 30c described later of the inflator 30. Bolts 25B and 25B disposed on the vehicle rear side (case opening 11a side) are air bag covers 33 disposed on the lower side of the inflator flange portion 30c in addition to the insertion hole 17 and the mounting holes 30d and 48b. The nut 27 is tightened by being inserted into the insertion hole 37 c disposed in the lower side wall portion 37. That is, the length of the bolt 25 </ b> B is set to be larger than that of the bolt 25 </ b> A by at least the thickness of the lower wall portion 37 of the airbag cover 33. Further, the bolt 25B has a configuration in which a spacer 28 is externally provided around a portion inserted through the insertion hole 37c. Each spacer 28 is set to have a length slightly longer than the thickness of the lower side wall portion 37, and a nut 27 is fastened to the tip side of the bolt 25 </ b> B protruding from the lower side wall portion 37, so that the airbag cover 33 is attached. When assembled to the case 11, the bolt 25 </ b> B is disposed so as to be able to move back and forth in the insertion hole 37 c formed in a long hole shape along the front-rear direction.

  The retainer 23 is inserted with the bolts 25A and 25B through the insertion holes 17 (37c) and the mounting holes 30d and 48b in a state where the base 24 is disposed in the airbag 45, and the protruding bolts 25A and 25B. By tightening a nut 27 at the tip of the airbag 11, the airbag 45, the inflator 30, and the lower wall portion 37 of the airbag cover 33 are attached to the lower wall portion 14 of the case 11. That is, when the nut 27 is tightened to each of the bolts 25 </ b> A and 25 </ b> B, the peripheral edge 48 of the gas inlet 48 a of the airbag 45 is pressed against the case lower wall portion 14 by the base portion 24, and the airbag 45 is pressed against the lower wall portion 14. The flange portion 30 c of the inflator 30 is attached to the peripheral edge of the insertion hole 16, and the inflator 30 is attached to the lower wall portion 14.

  The cover portion 26 has a rectangular tube shape and can cover the entire outer peripheral side of the main body portion 30a of the inflator 30 in the direction around the axis. The height dimension h1 is disposed on the side surface of the main body portion 30a. The dimension is set so as to cover the plurality of gas discharge ports 30b (see FIG. 2). Further, as shown in FIGS. 2, 3 and 5, the cover portion 26 is provided with an extending portion 26a so as to cover from the upper end side of the portion on the case bottom wall portion 21 side to the upper surface side of the inflator main body portion 30a. Is configured. The extending portion 26a cooperates with a portion 26b of the cover portion 26 on the rear side of the inflator 30, and causes the inflation gas discharged from the gas discharge port 30b to be obliquely upward on the rear side of the vehicle on the case opening 11a side. It is arranged as a rectifying member that flows out toward.

  The inflator 30 is a disk type including a substantially disc-shaped main body portion 30a having a plurality of gas discharge ports 30b on the upper outer peripheral surface as a pyro type that generates a gas for expansion by burning a predetermined gas generating agent. It is said. A flange portion 30c for attaching the inflator 30 to the case 11 is provided on the outer peripheral surface of the main body portion 30a. The flange portion 30c is formed in a substantially quadrangular ring shape (substantially square plate shape) protruding from the outer peripheral surface of the main body portion 30a, and the attachment holes 30d are passed through the four corners, respectively. Each mounting hole 30d is arranged at a position corresponding to each insertion hole 17 in the lower wall portion 14 of the case 11, and the inner diameter is set so that the bolt 25 (25A, 25B) of the retainer 23 can be inserted. Yes. An inflator whose length L1 of the main body 30a is about 2 to 3 times the outer diameter D1 of the main body 30a is usually called a disk-type inflator (see FIG. 2).

  The airbag cover 33 is made of an olefin-based thermoplastic elastomer or the like, is configured to cover the vehicle rear side of the case 11, and is assembled to the case 11. The airbag cover 33 is disposed on the lower panel 8b side of the instrument panel 8 as an interior member of the vehicle including the upper panel 8a and the lower panel 8b, and a door is disposed near the opening 11a of the case 11. A part 35 and a general part 34 arranged around the door arrangement part 35 are provided.

  A lower panel 8 b is disposed around the door arrangement portion 35 adjacent to the door arrangement portion 35. In the case of the embodiment, the door arrangement portion 35 and the lower panel 8b are arranged so that the vehicle rear side surface is substantially flush (see FIG. 3). And the door arrangement | positioning part 35 is provided with the door part 42 and the upper, lower, left, right side wall part 36 * 37 * 38 * 39 arrange | positioned in the site | part used as the periphery of the door part 42, and is comprised. Has been.

  The door portion 42 is formed to be slightly larger than the opening 11a of the case 11 and has a substantially rectangular plate shape covering the opening 11a. Further, the door portion 42 is disposed in accordance with the surrounding lower panel 8b so that the rear surface of the vehicle is inclined so that the upper side is positioned on the rear side and the lower side is positioned on the front side. In the case of the embodiment, it is composed of two door portions that open in the vertical direction. The door portions 42 and 42 are provided with hinge portions 41 serving as rotation centers when opened at the upper and lower ends, respectively, and are substantially H-shaped when viewed from the vehicle rear side around the door portion 42. The thin portion to be broken 40 is arranged at the site.

  The upper side wall portion 36, the lower side wall portion 37, the left side wall portion 38, and the right side wall portion 39 are disposed adjacent to the outer peripheral side of the peripheral wall portion 12 in the case 11 so as to protrude toward the vehicle front side. Has been. The upper side wall portion 36 disposed in the vicinity of the upper wall portion 13 and the lower side wall portion 37 disposed in the vicinity of the lower wall portion 14 are assembled pieces for assembling the airbag cover 33 to the case 11. The Rukoto. The upper and lower side wall portions 36 and 37 have locking hole portions 36a and 37a that are opened in a substantially rectangular shape for locking the locking claw portion 20 formed on the case peripheral wall portion 12 to the periphery, respectively. Arranged. Each of the locking holes 36a and 37a has an opening width dimension in the front-rear direction. When the airbag cover 33 is assembled to the case 11 by locking the tip 20a of the locking claw 20 to the periphery, The claw portion 20 is set to a dimension that allows movement in the front-rear direction within each of the locking hole portions 36a and 37a.

  In addition, a notch recess 37b that is cut out in a substantially arc shape is formed at a central portion in the left-right direction on the front end side of the lower wall portion 37 so that the main body 30a of the inflator 30 can be inserted. Insertion holes 37c and 37c through which the bolts 25B of the retainer 23 can be inserted are disposed on both the left and right sides in the vicinity of the rear end of the notch recess 37b. Each insertion hole 37c has a long hole shape along the front-rear direction so that the bolt 25B inserted therein can be moved in the front-rear direction.

  In other words, the airbag cover 33 is in a state in which the tip 20a of the locking claw 20 is locked to the periphery of each locking hole 36a, 37a, the bolt 25B of the retainer 23 is protruded from the insertion hole 37c, and the nut 27 is fixed. Thus, it is assembled to the case 11 so as to be movable in the front-rear direction with respect to the case peripheral wall portion 12. The notch recess 37b is set to a size that does not hinder the movement of the airbag cover 33 relative to the case 11.

  As shown in FIGS. 2 and 3, the general portion 34 is located on the vehicle front side from the door disposition portion 35 by the thickness of the lower panel 8 b so as not to interfere with the lower panel 8 b disposed around the door disposition portion 35. It is formed so as to be recessed.

  The airbag 45 has a width dimension in the left-right direction that can protect the knees K (KL and KR) of the driver MD as an occupant, as shown by the two-dot chain line in FIGS. It is made into the substantially rectangular plate shape provided with. The airbag 45 is formed of a woven fabric made of flexible polyester, polyamide yarn, or the like. As shown in FIGS. 7 and 8, the airbag 45 includes an occupant side wall 46 disposed on the occupant MD side when inflation is completed. A vehicle body side wall 47 disposed on the column cover 6 side. In the case of the embodiment, the airbag 45 is a flat airbag in which the walls 46 and 47 are formed in substantially the same shape, and the outer peripheral edges of the walls 46 and 47 are sewn together. . In the case of the embodiment, the wall portions 46 and 47 are formed from one piece of cloth material connected in the lower end 45b side of the airbag 45.

  Further, in the airbag 45, tethers 50 and 51 arranged along the left-right direction are arranged in two upper and lower stages. The tethers 50 and 51 are arranged so that the wall portions 46 and 47 can be connected to maintain the airbag 45 in a plate shape when the inflation is completed. Each of the tethers 50 and 51 is formed from two cloth materials that are connected to the walls 46 and 47 and connected to each other.

  A gas inlet 48 a for allowing the inflation gas discharged from the gas outlet 30 b of the inflator 30 to flow in is disposed in a portion 48 of the passenger side wall portion 46 on the lower end 45 b side of the airbag 45. The gas inflow port 48a is configured to open in a substantially circular shape so that the main body 30a of the inflator 30 can be inserted. A plurality (four in the case of the embodiment) of attaching the inlet periphery 48 to the lower wall portion 14 of the case 11 by inserting the bolts 25 (25A, 25B) of the retainer 23 through the periphery of the gas inlet 48a. A hole 48b is provided. That is, the airbag 45 of the embodiment is fixed to the lower wall portion 14 while surrounding the inflator main body portion 30a disposed in the case 11 over the entire periphery of the gas inlet 48a. It is the structure stored and hold | maintained.

  As shown in FIGS. 2 and 3, the airbag 45 of the embodiment is folded so that the center of gravity G near the center in the left-right direction when the case 11 is stored after being folded is arranged on the rear upper side of the inflator 30. And is housed in the case 11. Specifically, as shown in FIGS. 2 and 3, the airbag 45 has folded mass portions 53 a, 53 b, and 53 c in the case 11 and on the rear side and the left and right sides around the inflator 30. It will be stored.

  Next, mounting of the knee protection airbag device S1 of the embodiment on a vehicle will be described. First, the retainer 23 is accommodated in the airbag 45 so that the bolts 25A and 25B protrude from the mounting holes 48b.

  Next, the airbag 45 is folded so as to be folded along the left-right direction so as to reduce the width dimension in the front-rear direction, and the airbag 45 is folded so as to be folded along the front-rear direction to reduce the width dimension in the left-right direction. Fold through the vertical folding process. Specifically, as shown in FIG. 9, from the state in which the occupant side and the vehicle body side wall portions 46 and 47 are overlapped and flattened, a fold C1 is attached along the left and right direction as a lateral folding process, and the upper end 45a. The roll folding part 54 is formed by performing roll folding on the side of the vehicle body side wall 47 so that the side approaches the lower end 45b (gas inlet 48a) side. Thereafter, as a vertical folding process, as shown in FIGS. 9 and 10, the left and right ends 54 a and 54 b of the roll folding part 54 are placed above the gas inlet 48 a while approaching the center in the left and right direction, Folding part in which folding mass parts 53a, 53b, and 53c are arranged in a substantially U shape with the front side opened around the gas inflow port 48a by folding with creases C2 and C3 substantially along the front-rear direction. 53, and the folding of the airbag 45 is completed.

  Thereafter, the airbag 45 is wrapped together with the folded portion 53 with a wrapping material (not shown) that can be broken to prevent the folding. At this time, the bolts 25A and 25B of the retainer 23 protruding from the mounting hole 45b are protruded from the wrapping material.

  Next, the folded airbag 45 is inserted together with the retainer 23 from the case opening 11a, and the bolts 25A and 25B of the retainer 23 are projected from the insertion hole 17 through the opening 18, so that the case lower wall portion The airbag 45 placed and folded together with the retainer 23 is housed in the case 11. Thereafter, the upper portion of the main body 30a of the inflator 30 is inserted into the insertion hole 16, the gas inlet 48a, and the base 24 of the retainer 23 from below, and the bolts 25A 25B is inserted through the mounting hole 30d of the flange portion 30c of the inflator 30. Then, the nut 27 is fastened to each bolt 25A protruding from the flange portion 30c of the inflator 30.

  Next, while the bolts 25B with the spacers 28 are made to protrude from the insertion holes 37c, the tips 20a of the locking claws 20 are locked to the peripheral edges of the locking holes 36a and 37a. If the cover 33 is attached to the case 11 and the nut 27 is fastened to each bolt 25B protruding from the lower wall portion 37 of the airbag cover 33, the inflator 30, the airbag 45, and the airbag cover 33 are attached to the case. 11 can be assembled to form an airbag assembly. Then, if the mounting bracket 22 of the case 11 is fixedly attached to an instrument panel reinforcement or the like on the body side (not shown), and then the instrument panel 8 and the under cover 9 (see FIGS. 1 and 2) are attached, the knee protecting airbag device S1. Can be mounted on a vehicle.

  If the inflation gas is discharged from the gas discharge port 30b of the inflator 30 after the knee protection airbag device S1 is mounted on the vehicle, the inflation gas passes through the gas inlet 48a of the airbag 45 and passes through the airbag 45. Will flow in. The airbag 45 is inflated to break a wrapping material (not shown), presses the door portion 42 of the airbag cover 33, and breaks the planned fracture portion 40. Thereafter, the door portion 42 opens up and down with the hinge portion 41 as the center of rotation, and the airbag 45 is deployed and inflated as shown by the two-dot chain line in FIGS.

  In the knee protection airbag device S1 of the embodiment, the airbag 45 has the center of gravity G of the folded lump portion 53a in the vicinity of the center in the left-right direction when the case 11 is stored after being folded disposed on the rear upper side of the inflator 30. Thus, the air bag cover 33 is housed and held in the case 11 on the front side. That is, in the knee protecting airbag device S1 of the embodiment, the inflation gas discharged from the gas discharge port 30b of the inflator 30 at the initial stage of inflation of the airbag 45 causes the center of gravity G near the center of the airbag 45 in the left-right direction. The vicinity (the lump portion 53a) is pushed out toward the rear upper side. Therefore, the airbag 45 pushes and opens the door portions 42 and 42 of the airbag cover 33, cancels the folding, protrudes toward the rear side of the vehicle, and easily expands upward.

  Further, in the knee protection airbag device S1 of the embodiment, the inflator 30 is attached and fixed to the lower wall portion 14 of the case peripheral wall portion 12 by disposing the gas discharge port 30b in the case 11. It is easy to discharge the inflation gas toward the rear upper side in the case 11. Therefore, the inflating gas flowing inside the airbag 45 protruding from the case 11 can easily flow toward the rear upper side, and the aspect in which the airbag 45 expands upward while protruding toward the rear side of the vehicle is promoted. Will be.

  Further, in the knee protection airbag device S1 of the embodiment, the inflator 30 is attached and fixed at a position near the center in the left-right direction of the lower wall portion 14 in the case peripheral wall portion 12. Expansion in the left-right direction is also equalized, and it is possible to develop it quickly.

  Therefore, in the knee protection airbag device S1 of the embodiment, the airbag 45 can be rapidly deployed upward while protruding toward the vehicle rear side.

  In the knee protection airbag device S1 of the embodiment, the airbag cover 33 is disposed so as to be inclined so that the upper side is located on the rear side and the lower side is located on the front side. 11, the center of gravity G near the center in the left-right direction when the case 11 is stored after the airbag 45 is folded is easily arranged at a position on the rear upper side of the inflator 30.

  Moreover, in the airbag apparatus S1 for knee protection of the embodiment, the airbag 45 is configured to be folded through a horizontal folding process and a vertical folding process, and the folded mass parts 53b and 53c of the folding part 53 after the vertical folding process. However, as shown in FIGS. 2 and 3, the case 11 is housed in the left and right side portions around the inflator 30. Therefore, the folded mass portions 53b and 53c of the airbag 45 can also be stored in the left and right portions of the inflator 30, and the space in the case 11 can be used effectively. Further, in the knee protection airbag device S1 of the embodiment, the airbag 45 is rolled by winding on the side of the vehicle body side wall portion 47 so that the upper end 45a approaches the gas inlet 48a side in the lateral folding step. Since it is folded, during deployment, the airbag 45 is deployed so as to unwind this roll fold along the vehicle rear side surface of the surrounding lower panel 8b as shown by a two-dot chain line in FIG. It will be. Therefore, even if the knee K of the occupant MD is approaching the lower panel 8b, the airbag 45 can be deployed and inflated so as to smoothly enter the gap between the knee K and the lower panel 8b. Of course, if such a point is not taken into consideration, the airbag may be folded by bellows folding in which the fold folding and the valley folding are sequentially repeated in the lateral folding step.

  In the airbag apparatus S1 of the embodiment, the airbag cover 33 can absorb an assembly error with respect to the lower panel 8b (interior member) of the instrument panel 8 around the airbag cover 33 on the front side of the occupant MD. Thus, it is set as the structure assembled | attached with respect to the case surrounding wall part 12 so that a movement in the front-back direction is possible. Therefore, when the airbag device S1 is mounted on a vehicle, the airbag cover 33 is generated even if an assembly error occurs with respect to the lower panel 8b disposed around the airbag cover 33. The assembly panel can be moved relative to the lower panel 8b so as to absorb the assembly error and not cause a sense of incongruity with the lower panel 8b disposed around. Specifically, when the airbag device S1 is mounted on the vehicle, the instrument panel 8 can be mounted even if the airbag cover 33 protrudes more than necessary in the state in which the airbag assembly is attached and fixed to the vehicle. When attaching to the vehicle body side, the vehicle rear side surface of the general portion 34 is pushed into the vehicle front side together with the instrument panel 8, so that the vehicle rear side surface of the door disposition portion 35 is located on the vehicle rear side of the lower panel 8b. The airbag cover 33 can be moved so as to be substantially flush with the surface. Therefore, the design property seen from the vehicle inner side can be improved.

  Further, in the airbag device S1 of the embodiment, the lower wall portion 37 of the airbag cover 33 is formed on the lower wall of the case 11 by using bolts 25A and 25B and nuts 27 that are fixing means to the case 11 of the inflator 30. It is set as the structure assembled | attached to the part 14. FIG. Therefore, the number of locking claws 20 or the like for assembling the airbag cover 33 to the case 11 can be reduced, and the apparatus itself can be reduced in weight.

  In the embodiment, the insertion hole 37c for inserting the bolt 25B disposed in the lower side wall portion 37 of the airbag cover 33 is formed in a long hole shape along the front-rear direction, and between the bolt 25B and the insertion hole 37c. In the state where the spacer 28 is interposed, the nut 27 is fixed, and the lower side wall portion 37 of the airbag cover 33 is assembled so as to be movable with respect to the case peripheral wall portion 12. For example, FIG. As shown in the airbag apparatus shown in FIG. 2, the insertion hole 37e for inserting the bolt 25B disposed in the lower side wall portion 37A of the airbag cover 33A has a substantially circular shape, and the spacer 28 is provided between the bolt 25B and the insertion hole 37e. Without interposing, the lower wall portion 37A of the airbag cover 33A cannot be moved with respect to the case peripheral wall portion 12 and is fastened together with the case 11 together with the inflator 30. It may be configured that. In the case of such a configuration, the airbag cover 33A can be firmly attached and fixed to the case 11. In such a configuration, the lower part of the airbag cover 33A is assembled so as not to move with respect to the case 11, but the lower part of the airbag cover 33A is the knee of the seated occupant. And is disposed at a position closer to the front side of the vehicle than the upper portion, so that it is difficult for the occupant to see from the inside of the vehicle. Even if some assembling errors occur between the lower panel 8b of the surrounding instrument panel 8, the design as viewed from the inside of the vehicle is not greatly deteriorated. If these points are not taken into consideration, the lower side wall portion of the airbag cover is placed under the case without using the fixing means to the case of the inflator as in the airbag device S2 shown in FIGS. It is good also as a structure attached and fixed to a wall part.

  Furthermore, in the knee protection airbag device S1 of the embodiment, the retainer 23 for attaching the airbag 45 to the case 11 extends upward from the base 24 that holds the gas inlet peripheral edge 48 of the airbag 45 and the outer peripheral edge of the base 24. As a cylindrical shape, a cover portion 26 that can cover the gas discharge port 30b of the inflator 30 is provided. Therefore, the inflation gas discharged from the gas discharge port 30b does not directly hit the base fabric constituting the airbag 45, and the airbag 45 can be prevented from being damaged by the inflation gas.

  Further, in the retainer 23 used in the airbag device S1 of the embodiment, the extended portion 26a that covers the upper surface side of the inflator main body portion 30a in the cover portion 26 and the portion 26b that is on the rear side of the inflator 30 provide gas. The expansion gas discharged from the discharge port 30b is rectified so as to go diagonally upward on the rear side of the vehicle on the case opening 11a side, and further expands and expands to the rear upper side of the airbag 45. Can promote. In addition, the part 26b which becomes the back side of the inflator 30 in the cover part 26 is good also as a structure arrange | positioned so that an upper end side may be located back, as shown to the dashed-two dotted line of FIG. Of course, if these points are not taken into consideration, it is possible to use a retainer that does not include a cover portion and attach the airbag to the case.

  Furthermore, in the knee protection airbag device S1 of the embodiment, the insertion holes 17 through which the bolts 25A and 25B of the retainer 23 are inserted in the case lower wall portion 14 respectively extend toward the opening 11a side of the case 11. A portion 18 is provided and formed. Therefore, when the airbag 45 is attached to the case 11 using the retainer 23, the lower end of the bolt 25 of the retainer 23 is inserted into the opening 18 and the bolt 25 is disposed at a predetermined position (insertion hole 17) on the front side. This makes it easy to insert the retainer 23 into the case 11 where the distance between the upper wall portion 13 and the lower wall portion 14 is narrow, and the workability of attaching the airbag 45 to the case 11 is improved. In particular, in the knee protection airbag device S1, in the vehicle, peripheral devices are arranged in the vicinity of a portion where the airbag device S1 is mounted, so that the device S1 itself can be made as compact as possible. It is desired. Therefore, the case 11 has a small interval between the upper wall portion 13 and the lower wall portion 14 so that the retainer 23 and the folded airbag 45 can be accommodated without gaps, and the case 11 is compact. Will be formed. However, as in the airbag device S1 of the embodiment, the opening 18 extending toward the opening 11a of the case 11 is disposed in the insertion hole 17 for inserting the bolts 25A and 25B of the retainer 23 in the case lower wall portion 14. When the retainer 23 is housed in the case 11 from the opening 11a together with the folded airbag 45, the bolt 25A protruding from the base 24 is inserted into the opening 18, Since the front end side of the base 24 can be tilted downward and inserted, the retainer 23 and the folded airbag 45 can be folded into the case 11 without any problem even if the case 11 is compact. Can be stored. Of course, if such a point is not taken into consideration, the insertion holes for inserting the bolts 25A and 25B formed in the case lower wall portion 14 may be substantially circular so that no opening is provided.

  Further, in the airbag apparatus S1 of the embodiment, the retainer 23 is disposed in the case 11 so that the front and rear edges of the substantially square base 24 are substantially along the bottom wall 21 of the case 11. However, as shown by a two-dot chain line in FIG. 13, the retainer 23A may be arranged in the case 11A by shifting the edge of the base 24A by approximately 45 ° when viewed from above. Even in such a configuration, the insertion hole 17A disposed in the case lower wall portion 14A is long along the front-rear direction so that the opening 18A is disposed on the vehicle rear side (case opening side). If it forms in a hole shape, the insertion operation | work to each insertion hole 17A of each volt | bolt 25 (25A * 25B) will become easy.

  Next, a knee protecting airbag device S2, which is another embodiment of the present invention, will be described. The knee protection airbag device S2 is similar to the knee protection airbag device S1 described above, so that the knee MD (KL / KR) of the driver MD as the passenger can be protected in front of and below the knee K of the passenger MD. It is arrange | positioned under the steering column 2 which is the side, and is the structure similar to above-mentioned airbag apparatus S1 except the case 58. FIG. Therefore, the same members are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 14, the case 58 is made of sheet metal, and has a substantially rectangular tube-shaped peripheral wall portion 59 that is disposed so that its axial direction is substantially along the front-rear direction, and the front end side of the peripheral wall portion 59 (front of the vehicle). A bottom wall portion 63 that closes the rear side, and the rear end side (rear side of the vehicle) is configured as an opening 58a for protruding the airbag 45. The upper wall part 60 which opposes the upper and lower sides in the surrounding wall part 59 is comprised so that the site | part of the vehicle front side may be dented. That is, the upper wall portion 60 is disposed so as to be inclined so that the front end side is positioned downward on the front side of the wall portion 60a and the wall portion 60a disposed substantially parallel to the lower wall portion 62 on the opening 58a side. The inclined wall portion 60b is connected to the front end of the inclined wall portion 60b and the upper end of the bottom wall portion 63, and the wall portion 60c is disposed substantially parallel to the lower wall portion 62. The concave portion 61 surrounded by the inclined wall portion 60b and the wall portion 60c is disposed in order to avoid interference with an electric column motor housing (not shown) disposed in the column main body 3 of the steering column 2. Similarly to the lower wall portion 14 described above, the lower wall portion 62 includes an insertion hole 16 for inserting a body portion 30a described later of the inflator 30, an insertion hole 16, and an insertion hole 17 having an opening portion 18. Are arranged. Further, the portion of the wall portion 60a in the upper wall portion 60 and the lower wall portion 62 are provided with a plurality of locking claws 20 for assembling the airbag cover 33A to the case 58, as in the case 11 described above. , Has been projecting.

  In the airbag device S2 of the embodiment, the flange portion 30c of the inflator 30 can be inserted into the center portion in the left-right direction on the front end side of the lower wall portion 37A of the airbag cover 33A as shown in FIGS. In addition, a notched recess 37d is formed. That is, in the airbag device S2 of the embodiment, the airbag cover 33A is assembled to the case 58 using only the locking claw portion 20 without using the bolt 25 for fixing the inflator 30 to the case 58. It is a configuration.

  Also in the airbag device S2 having the above-described configuration, the airbag 45 is stored and held in the case 58 with the center of gravity G near the center in the left-right direction when the case 11 is stored after being folded disposed at the upper rear side of the inflator 30. Since it is the structure currently performed, the effect similar to the above-mentioned airbag apparatus S1 can be acquired.

  Further, in the airbag device S2 having the above-described configuration, the upper wall portion 60 of the case peripheral wall portion 59 is configured to include the concave portion 61 in the portion on the front side of the vehicle. The part which becomes the lower end side in the side wall part 47 expands along the concave part 61, and the part in the vicinity of the case opening 58 a in the side wall part 47 of the vehicle body is tacked. That is, in the airbag device S2, when the airbag 45 is deployed and inflated, the upper end 45a side of the airbag 45 is pulled toward the vehicle body side wall portion 47 side, that is, the lower panel 8b side, thereby completing the inflation. Therefore, it becomes easy to deploy and inflate the airbag 45 along the surrounding lower panel 8b.

  In the airbag apparatuses S1 and S2 of the embodiment, the airbag 45 is configured such that the gas inflow port 48a is disposed in the portion 48 of the occupant side wall portion 46 on the lower end 45b side. As shown in FIG. 16, the gas inlet 66 is arranged on the lower end 65a side of the airbag 65 so as to be separated from the upper end side of the occupant side wall portion 46 so as to straddle the lower end 65b of the flatly deployed airbag 65. You may use the airbag 65 of the structure provided. That is, in the airbag 65 having the above-described configuration, the position of the gas inlet 66 moves to the lower end 65b side when the inflation is completed, as compared with the airbag 45 described above. The substantial film length of the vehicle body side wall 47 from the inlet 66 to the upper end 65a can be relatively shortened, and the tension acting on the vehicle body side wall 47 without changing the position of the inflator in the case. Can be made larger than the tension acting on the occupant side wall 46. Therefore, when the inflation of the airbag 65 is completed, a greater tension acts on the side of the vehicle body side wall 47 than on the side of the occupant side wall 46, and the airbag 65 has an upper end 65 a side on the side of the vehicle body side wall 47. The expansion is completed by being pulled toward the lower panel 8b. As a result, it is easy to deploy and inflate the airbag 65 along the surrounding lower panel 8b.

  In the airbag apparatuses S1 and S2 of the embodiment, the airbag 45 is folded and stored so that the folding portion 53 is placed above the inflator 30 (retainer 23). It is not limited. For example, as shown in FIG. 17, the roll folding portion 54 after the horizontal folding step is provided with folds C4 and C5 along the front-rear direction so that the left and right ends 54a and 54b simply approach the center side. The folded portion 53A of the airbag 45 may be formed so that the folded lump portions 53b and 53c overlap the lump portion 53a on the rear side.

  In the embodiment, the knee protection airbag devices S1 and S2 that are disposed below the steering column 2 and protect the knee K of the driver MD have been described as an example. The airbag device can also be applied to a knee protection airbag device disposed in front of the passenger seat in order to protect the passenger's knees seated in the passenger seat.

It is a schematic longitudinal cross-sectional view of the vehicle front-back direction which shows the use condition of the airbag apparatus for knee protection which is one Embodiment of this invention. It is a general | schematic expanded longitudinal cross-sectional view of the vehicle front-back direction in the airbag apparatus for knee protection of embodiment, and respond | corresponds to the II-II site | part of FIG. It is a general | schematic expanded cross-sectional view of the vehicle front-back direction in the airbag apparatus for knee protection of embodiment, and respond | corresponds to the III-III site | part of FIG. It is a bottom view of the airbag assembly | attachment body in the airbag apparatus for knee protection of embodiment. It is the outline exploded perspective view which looked at the air bag cover, case, retainer, and inflator used for the air bag device for knee protection of an embodiment from the vehicle front side. It is a top view which shows the insertion hole vicinity in the case lower wall part used for the airbag apparatus for knee protection of embodiment. It is a schematic front view which shows the airbag of the deployment state which incorporated the retainer used for the airbag apparatus for knee protection of embodiment. It is a schematic sectional drawing of the VIII-VIII site | part of FIG. It is a figure explaining the folding process of the airbag used for the airbag apparatus for knee protection of embodiment. It is a figure explaining the folding process of the airbag used for the airbag apparatus for knee protection of embodiment, and is a figure explaining the process after FIG. It is the schematic front view seen from the vehicle back side which shows the use condition of the airbag apparatus for knee protection of embodiment. It is a schematic longitudinal cross-sectional view of the vehicle front-back direction in the airbag apparatus for knee protection which uses the airbag cover of another form. It is a top view which shows the insertion hole and insertion hole of the other form in a case lower wall part. It is a general | schematic expanded longitudinal cross-sectional view of the vehicle front-back direction in the airbag apparatus for knee protection of other embodiment of this invention. It is a bottom view of the airbag assembly body in the airbag apparatus for knee protection of FIG. It is a schematic front view which shows the airbag of another form. It is a figure explaining the other folding process of an airbag.

Explanation of symbols

8 ... Instrument panel (interior member),
11.58 ... Case,
11a, 58a ... opening,
12.59 ... Surrounding wall,
13.60 ... Upper wall,
14.62 ... lower wall,
16 ... insertion hole,
17.17A ... insertion hole,
18.18A ... opening,
20 ... locking claw part,
21.63 ... bottom wall,
23 ... Retainer,
24 ... the base,
25 (25A / 25B) ... bolts,
26 ... cover part,
27 ... Nut,
28 ... Washers,
30 ... Inflator,
30a ... main body,
30b Flange part,
33 ・ 33A ・ 33B… Airbag cover,
36 ... upper side wall,
36a ... Locking hole,
37, 37A, 37B ... lower side wall,
37a ... Locking hole,
37b, 37d ... notch recess,
37c, 37e ... insertion hole,
45.65 ... Airbag,
46: Passenger side wall,
47 ... the side wall of the vehicle body,
48a, 66 ... gas inlet,
53.53A ... Folding part,
53a, 53b, 53c ... fold lump part G ... center of gravity,
K (KL / KR) ... Knee,
MD ... Crew,
S1, S2 ... Knee protecting airbag device.

Claims (7)

The airbag, which is folded and stored in the case placed on the front lower side of the seated occupant's knee, is inflated by the inflation gas supplied from the inflator and pushes the airbag cover held in the case As a configuration that opens and projects from the case to the vehicle rear side and expands and expands upward,
The case is provided with a substantially rectangular tube-shaped peripheral wall portion whose front end side is closed by a bottom wall portion, and whose rear end side is an opening for protruding the airbag, and whose axial direction is substantially along the front-rear direction. Configured
The inflator is a knee protection airbag device having a disk shape in which a plurality of gas discharge ports are disposed on the outer peripheral surface as a substantially disk shape,
The gas discharge port is disposed in the case at a position near the center in the left-right direction of the lower wall portion that is opposed to the upper and lower sides of the case peripheral wall portion, and the inflator is attached and fixed.
The airbag cover is disposed at an inclination so that the upper side is positioned on the rear side and the lower side is positioned on the front side on the rear side of the opening of the case,
The airbag is fixed to the lower wall portion while surrounding the inflator in the case while surrounding the entire periphery of the gas inlet through which the inflating gas flows, and in the lateral direction when the case is stored after folding. A knee protection airbag device characterized in that a center of gravity in the vicinity of the center is disposed on the rear upper side of the inflator and is stored and held in the case on the front side of the airbag cover. The airbag has a fold along the left-right direction at the upper end when the inflation is completed, and a fold along the front-rear direction at the left and right ends when the inflation is completed. As a structure that is folded by a vertical folding process that is attached to the center side in the left-right direction,
2. The knee protection airbag device according to claim 1, wherein the folded mass portions after the vertical folding step are stored in left and right side portions around the inflator in the case. The airbag cover is movably assembled to the peripheral wall portion of the case so as to be able to absorb an assembly error with respect to an interior member around the airbag cover on the front side of the occupant. ,
The assembly part with respect to the lower wall part of the said peripheral wall part in the said airbag cover is assembled | attached to the said case using the fixing means to the said case of the said inflator, The Claim 1 or 2 characterized by the above-mentioned. The airbag apparatus for knee protection as described. The airbag cover is
In order to absorb the assembly error for the interior member around the airbag cover on the front side of the occupant, the upper side portion which is the upper wall side of the case, with respect to the case, Moveable, assembled,
The knee protection airbag device according to claim 1 or 2, wherein a lower side portion which is the case lower wall side is fastened together with the inflator to the case. The airbag includes a vehicle body side wall portion disposed on the vehicle body side when the inflation is completed with substantially the same outer shape and an occupant side wall portion disposed on the occupant side, and an outer peripheral edge of the vehicle body side / occupant side wall portion As a flat air bag type formed by joining each other,
The gas inlet of the airbag is configured such that the tension acting on the side wall of the vehicle body is made larger than the tension acting on the side wall of the passenger and the upper end side of the airbag when inflation is completed is pulled to the vehicle body side. 5. The knee protection airbag according to claim 1, wherein the position of the knee protection airbag is set at a position away from the upper end side of the occupant side wall along the peripheral wall of the airbag. apparatus. The airbag is configured to attach a peripheral edge of the gas inlet to the case using an annular retainer disposed in the airbag.
The retainer includes a base that presses the periphery of the gas inlet, and a cover that covers the gas discharge port of the inflator as a cylindrical shape that extends upward from the outer periphery of the base. The airbag device for knee protection according to any one of claims 1 to 5. The airbag is configured to attach a peripheral edge of the gas inlet to the case using an annular retainer disposed in the airbag.
The retainer has a base that presses the periphery of the gas inlet, and a plurality of bolts that extend downward from the base so as to penetrate the case lower wall and are fixed to the case lower wall by being nut-fastened. And a configuration comprising:
The case lower wall portion includes an insertion hole for allowing the bolt to pass through,
The knee protection airbag device according to any one of claims 1 to 6, wherein the insertion hole is formed to include an opening extending toward an opening side of the airbag projecting in the case. .

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