Attachment Structure of Knee Airbag

Abstract

To provide an attachment structure of a knee airbag which enables an airbag to be deployed more properly.SOLUTION: An attachment structure of a knee airbag includes: a knee airbag case 22 which houses an airbag 26 in a folded state; a knee airbag door 30 in which a door body 32, a flange part 34 which protrudes from the door body 32 to the outer side in a surface direction to be hidden on the rear side of an instrument panel 10, and a connection part 36 connected to the knee airbag case 22 are integrally formed; and a bracket 52 having a sandwiching wall 54 which is located on the opposite side of the instrument panel 10 across the flange part 34. On the flange part 34, a projection 42 is formed. On the sandwiching wall 54, an insertion hole 56 into which the projection 42 is inserted is formed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This specification discloses an attachment structure of a knee airbag that expands and deploys to protect the lower limbs of an occupant during a vehicle collision.

Background Art

[0002] Conventionally, a knee airbag that protects the lower limbs of an occupant during a vehicle collision has been known. For example, Patent Document 1 discloses a knee airbag device that houses an inflator and an airbag inside a case body and supports this case body with a cover body. An opening for passing the inflated and deployed airbag is formed in an instrument panel (hereinafter referred to as "IP"), and the cover body covers this opening. Further, the cover body has a plurality of fitting claws and is attached to the IP by these fitting claws.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when the airbag deploys, a large reaction force acts on the case body and the cover body that supports the case body. This reaction force is in the direction opposite to the deployment direction of the airbag and is forward in the vehicle. When the cover body moves forward in the vehicle with respect to the IP in response to this reaction force, a gap is generated between the cover body and the IP. If a part of the airbag enters this gap, there is a risk that the airbag cannot be properly deployed outside the IP, that is, in the passenger compartment.

[0005] Therefore, this specification discloses an attachment structure of a knee airbag that can deploy the airbag more appropriately.

Means for Solving the Problems

[0006] The knee airbag mounting structure disclosed in this specification includes a knee airbag case that houses the folded knee airbag that inflates and deploys during a collision and is disposed in the inner panel space surrounded by the instrument panel, a door body that closes the door opening formed in the instrument panel, a flange portion that protrudes outward in the surface direction from the door body and is hidden behind the instrument panel, and a connecting portion that is connected to the knee airbag case. The knee airbag door is integrally formed, and a bracket fixed to the inner panel space, the bracket having a clamping wall located on the opposite side of the instrument panel across the flange portion. One of the flange portion and the clamping wall is formed with a protrusion protruding toward the other, and the other of the flange portion and the clamping wall is formed with an insertion hole into which the protrusion is inserted. This is the gist of the invention.

[0007] By sandwiching the flange portion between the clamping wall and the inner panel, it is possible to effectively prevent the flange portion, and thus the knee airbag door and the knee airbag case, from moving in a direction away from the inner panel. Further, by providing a protrusion on one of the flange portion and the clamping wall and an insertion hole on the other, it is possible to effectively prevent the flange portion from falling or bending, and effectively prevent the flange portion from slipping through the gap between the inner panel and the clamping wall. As a result, displacement of the knee airbag door and the knee airbag case can be effectively prevented, and the airbag can be deployed more appropriately.

[0008] In this case, the protrusion may be formed on the flange portion, and the insertion hole may be formed on the clamping wall.

[0009] By forming a protrusion on the flange portion, the rigidity of the flange portion is improved, and the deflection of the flange portion can be effectively prevented. As a result, it is possible to more reliably prevent the flange portion from passing through the gap between the instrument panel and the clamping wall. Note that since the bracket including the clamping wall is made of metal and often has high rigidity, even if an insertion hole is formed, the clamping wall is less likely to deflect or the like.

[0010] Further, the protrusion or the insertion hole is formed near the upper end of the flange portion, and the clamping wall may extend downward from a position above the upper end of the flange portion.

[0011] With such a configuration, it is possible to more effectively prevent the knee airbag from entering the gap between the knee airbag door and the instrument panel. That is, usually, after the knee airbag pops out from the interior space of the instrument panel toward the passenger compartment side, it spreads widely upward. Therefore, the knee airbag during deployment is more likely to enter the gap near the upper edge than the gap near the lower edge of the door opening. By providing a protrusion near the upper end of the flange portion, it is possible to more reliably prevent the occurrence of a gap between the knee airbag door and the instrument panel near the upper edge of the door opening. As a result, the airbag can be deployed more appropriately.

[0012] Further, the protrusion may have a cross-sectional cross shape.

[0013] With such a configuration, it is possible to keep the rigidity of the protrusion high while suppressing the volume of the protrusion to be small.

Effect of the Invention

[0014] According to the knee airbag mounting structure disclosed in this specification, the airbag can be deployed more appropriately.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0016] Hereinafter, the mounting structure of the knee airbag will be described with reference to the drawings. FIG. 1 is a view of the knee airbag device 20 as seen from the inside of the instrument panel internal space 12. Further, FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1, and FIG. 3 is an enlarged view of part B in FIG. 2. In each of the following figures, "Fr", "Up", and "Rh" indicate the front, upper, and right sides of the vehicle, respectively.

[0017] As shown in FIG. 2, an instrument panel 10 is provided at the front part of the vehicle. The space surrounded by this instrument panel 10 is the instrument panel internal space 12. A steering column 16 protrudes from the instrument panel 10 toward the rear of the vehicle (that is, the direction approaching the occupant), and a steering wheel 18 is attached to the tip of this steering column 16. The instrument panel 10 is formed with a column opening 17 (see FIG. 1) for passing the steering column 16.

[0018] A knee airbag device 20 is provided below the steering column 16. The knee airbag device 20 is a device that inflates and deploys an airbag 26 housed in the instrument panel internal space 12 so as to spread around the lower limbs of the occupant when the vehicle collides with an obstacle, thereby protecting the lower limbs of the occupant. Of course, the steering column 16 is provided only in front of the driver's seat, while the knee airbag device 20 is provided in front of both the driver's seat and the passenger seat.

[0019] Such a knee airbag device 20 has a knee airbag case 22 and a knee airbag door 30. The knee airbag case 22 is disposed in the instrument panel inner space 12. In the instrument panel 10, a door opening 14 (see FIG. 3) is formed at a location facing the knee airbag case 22 in the vehicle front-rear direction.

[0020] As shown in FIGS. 1 and 2, the knee airbag case 22 has a case body 24. The case body 24 is a substantially box-shaped container with an opening on the vehicle rear side surface, that is, the surface facing the door opening 14. An inflator 28 and an airbag 26 (not visible in FIG. 1, see FIG. 2) are accommodated inside the case body 24. The inflator 28 generates gas (e.g., nitrogen gas, etc.) during a vehicle collision and inflates and deploys the airbag 26. For example, it has a substantially cylindrical shape. The airbag 26 is a bag-shaped member and is normally accommodated in the case body 24 in a small, folded state. During a vehicle collision, the airbag 26 inflates and deploys with gas and pops out to the outside of the instrument panel inner space 12 to restrict the movement of the occupant's lower limbs, thereby protecting the occupant's lower limbs. The two-dot chain line in FIG. 2 shows the shape of the inflated and deployed airbag 26. As is clear from FIG. 2, after the airbag 26 pops out to the outside of the instrument panel 10, it has a shape that spreads upward, that is, in a side view, it spreads in a substantially L shape.

[0021] The knee airbag door 30 is a component that covers the door opening 14 and holds the knee airbag case 22. As shown in FIG. 2, the knee airbag door 30 is a resin component integrally formed with a door body 32, a flange portion 34, and a connecting portion 36.

[0022] The door body 32 (not visible in Fig. 1, refer to Fig. 2) is a part that covers the door opening 14. The outer surface of the door body 32 is smoothly continuous with the outer surface of the instrument panel 10. A tear line (not shown), which is a line formed by locally reducing the plate thickness, is formed on the door body 32. The tear line in this example is in a substantially "H" shape including a pair of vertical lines extending in the vertical direction near both ends in the vehicle width direction of the door body 32 and a horizontal line connecting the vertical centers of the pair of vertical lines in the vertical direction. When subjected to strong pressure, the door body 32 breaks along this tear line. Therefore, when an outward pressure acts on the door body 32 with the inflation and deployment of the airbag 26, the door body 32 breaks along the substantially "H"-shaped tear line. Due to this breakage, two flaps 32a are formed on the door body 32 vertically. These two flaps 32a swing greatly outward in a double-leaf door manner. And thereby, an opening for the airbag 26 to pass through is formed. In Fig. 2, the flaps 32a when the airbag 26 is inflated and deployed are shown by a two-dot chain line.

[0023] The flange portion 34 is a part that projects outward in the plane direction from the peripheral edge of the door body 32. This flange portion 34 is located on the front side of the vehicle from the instrument panel 10 and is not visible to the occupant as it is hidden behind the instrument panel 10. A plurality of fastening holes 40 are formed in the flange portion 34. At the location corresponding to the fastening holes 40 of the instrument panel 10, clips 44 stand upright. And by inserting and fitting this clip 44 into the fastening hole 40, the knee airbag door 30 is attached to the instrument panel 10.

[0024] In the vicinity of the upper end of this flange portion 34, there are provided projections 42 that protrude toward the front side of the vehicle, that is, in a direction away from the instrument panel 10. As shown in FIG. 1, two projections 42 are provided, one near each of the both ends in the vehicle width direction of the knee airbag door 30, for a total of two. As shown in FIG. 1, this projection 42 has a substantially cross-shaped cross section. By adopting such a shape, while suppressing the volume of the projection 42 to be small, the strength can be improved. As will be described later, among the flange portion 34, the periphery of the projection 42 faces the clamping wall 54 of the bracket 52. Hereinafter, the portion of the flange portion 34 that faces the clamping wall 54 will be referred to as the "stopper portion 35" (see FIG. 3).

[0025] From the back surface of the door body 32 (that is, the surface not visible to the occupant), a connecting portion 36 (not visible in FIG. 1, see FIG. 2) protrudes toward the rear of the vehicle. The connecting portion 36 is a wall member to which the case body 24 is connected at its end. For example, fitting claws (not shown) are formed at the end of the connecting portion 36, and these fitting claws are inserted into and fitted into holes formed in the case body 24.

[0026] The bracket 52 is a sheet metal member fixed inside the instrument panel internal space 12. This bracket 52 is fixed to, for example, an instrument panel reinforcement (hereinafter referred to as "instrument panel R / F") 50 by welding or the like. The instrument panel R / F 50 is a pipe material that is long in the vehicle width direction, and both ends thereof are welded to the front pillar.

[0027] The bracket 52 has a clamping wall 54 located on the opposite side of the instrument panel 10 with the stopper portion 35 interposed therebetween. This clamping wall 54 extends downward from above the upper end of the flange portion 34 as shown in FIGS. 1 and 3, and the lower end of the clamping wall 54 is located below the projection 42. The stopper portion 35 is sandwiched between this clamping wall 54 and the instrument panel 10. In the portion of the clamping wall 54 corresponding to the projection 42, an insertion hole 56 for passing the projection 42 is formed. This insertion hole 56 is slightly larger than the projection 42.

[0028] As is clear from the above description, in this example, a clamping wall 54 is provided to sandwich the stopper portion 35 in cooperation with the instrument panel 10, and further, a protrusion 42 and an insertion hole 56 are formed in the stopper portion 35 and the clamping wall 54. The reason for such a configuration will be described in comparison with the prior art.

[0029] Conventionally, although the knee airbag door 30 is fitted to the instrument panel 10 with a clip 44 or the like, a clamping wall 54 for sandwiching the knee airbag door 30 between the instrument panel 10 has not been provided. In this case, when the airbag 26 expands and deploys, the entire knee airbag device 20 moves forward of the vehicle, and there is a possibility that the airbag 26 may not expand properly.

[0030] That is, when the airbag 26 expands and deploys, a large reaction force in the vehicle forward direction (i.e., opposite to the deployment direction of the airbag 26) acts on the case body 24 and the knee airbag door 30 to which the case body 24 is connected. In response to this reaction force, the fastening between the knee airbag door 30 and the instrument panel 10 by the clip 44 is released, and the knee airbag door 30 and the case body 24 may move to the front side of the vehicle. In this case, a gap is generated between the knee airbag door 30 and the instrument panel 10. Then, the airbag 26 during deployment may enter this gap, and the airbag 26 may not expand into a desired shape.

[0031] To avoid such problems, as shown in FIG. 5, it is conceivable to provide a clamping wall 54 and sandwich the vicinity of the upper end of the flange portion 34 (i.e., the "stopper portion 35") between the clamping wall 54 and the instrument panel 10. By providing such a clamping wall 54, the forward movement of the knee airbag door 30 in the vehicle is suppressed to some extent. However, as shown in FIG. 5, in the case of a configuration in which the protrusion 42 is not provided on the flange portion 34, the flange portion 34 easily swings or bends under the reaction force in the vehicle forward direction.

[0032] That is, as the airbag 26 expands and deploys, when a vehicle forward reaction force acts on the knee airbag door 30, the flange portion 34 tends to move forward in the vehicle. When the flange portion 34 moves forward in the vehicle, the stopper portion 35 interferes with the clamping wall 54. Since the stopper portion 35 has less rigidity than the clamping wall 54, when the reaction force continues to act thereafter, the stopper portion 35 falls backward or deflects toward the rear side of the vehicle so as to eliminate the interference with the clamping wall 54. And due to the continuous occurrence of such falling and deflection of the stopper portion 35, finally, the stopper portion 35 passes under the clamping wall 54, and as shown in FIG. 6, there was a possibility that the entire knee airbag device 20 would move significantly forward in the vehicle.

[0033] In this example, in order to prevent such falling and deflection of the stopper portion 35, a protrusion 42 is formed on the stopper portion 35, and an insertion hole 56 through which the protrusion 42 is inserted is formed in the clamping wall 54. In this configuration, the movement of the stopper portion 35 when the airbag 26 expands and deploys is shown in FIG. 4. As the airbag 26 expands and deploys and a reaction force acts, the stopper portion 35 moves forward in the vehicle, but relatively early, it interferes with the clamping wall 54. In order to eliminate this interference, when the stopper portion 35 tries to fall backward, as shown in FIG. 4, since the protrusion 42 interferes with the periphery of the insertion hole 56, further backward falling of the stopper portion 35 is restricted. As a result, when the protrusion 42 is provided, the stopper portion 35 can hardly fall backward. Further, by providing the protrusion 42, the rigidity of the stopper portion 35 is significantly improved, so the stopper portion 35 is less likely to deflect. That is, by providing the protrusion 42, the falling and deflection of the stopper portion 35 are effectively prevented. And thereby, the knee airbag device 20 is effectively prevented from moving forward in the vehicle, and as a result, the airbag 26 can be properly deployed.

[0034] Also, as described above, in this example, the protrusion 42 is provided near the upper end of the knee airbag door 30. With such a configuration, the airbag 26 can be deployed more appropriately. That is, as described above and as shown in FIG. 2, after the airbag 26 pops out from the inner panel internal space 12 toward the passenger compartment side, it spreads widely upward. Therefore, the airbag 26 during deployment is more likely to enter the gap near the upper edge than the gap near the lower edge of the door opening 14. When the protrusion 42 is provided near the upper end of the flange portion 34, such a gap near the upper edge is less likely to occur, so that it is possible to effectively prevent the airbag 26 from entering the gap, and the airbag 26 can be deployed more appropriately.

[0035] Note that the configuration described so far is an example. As long as the protrusion 42 is formed on one of the flange portion 34 and the clamping wall 54, and the insertion hole 56 is formed on the other, the other configurations may be changed as appropriate. For example, the shape of the protrusion 42 may be changed as appropriate. For example, the protrusion 42 may have a cylindrical shape, a conical shape, a prismatic shape, or the like. Also, the insertion hole 56 may be formed in the flange portion 34, and the protrusion 42 may be formed in the clamping wall 54. However, when the insertion hole 56 is formed in the flange portion 34, the rigidity of the flange portion 34 is reduced accordingly. Therefore, when the insertion hole 56 is formed in the flange portion 34, a structure for ensuring rigidity, such as forming ribs in the flange portion 34, may be provided.

[0036] Also, in the above description, two protrusions 42 are provided near the upper end of the flange portion 34, but the position and number of the protrusions 42 may be changed as appropriate. For example, the protrusion 42 may be provided near the lower end in addition to or instead of near the upper end of the flange portion 34.

Explanation of Reference Numerals

[0037] 10 Instrument panel, 12 Interior space of instrument panel, 14 Door opening, 16 Steering column, 18 Steering wheel, 20 Knee airbag device, 22 Knee airbag case, 24 Case body, 26 Airbag, 28 Inflator, 30 Knee airbag door, 32 Door body, 32a Flap, 34 Flange portion, 35 Stopper portion, 36 Connecting portion, 40 Fastening hole, 42 Projection, 44 Clip, 52 Bracket, 54 Clamping wall, 56 Insertion hole.

Claims

1. A knee airbag case that houses the knee airbag in a folded state and expands and deploys during a collision, and is disposed in an inner panel space surrounded by an instrument panel, a door body that closes a door opening formed in the instrument panel, a flange portion that protrudes outward in the plane direction from the door body and is hidden behind the instrument panel, and a connecting portion that is connected to the knee airbag case, are integrally formed knee airbag door, a bracket fixed to the inner panel space, the bracket having a clamping wall located on the opposite side of the instrument panel across the flange portion, Comprising, a protrusion protruding toward the other is formed on one of the flange portion and the clamping wall, On the other of the flange portion and the clamping wall, an insertion hole into which the protrusion is inserted is formed. A mounting structure for a knee airbag, characterized in that.

2. The mounting structure for a knee airbag according to claim 1, The mounting structure for a knee airbag, characterized in that the protrusion is formed on the flange portion and the insertion hole is formed on the clamping wall.

3. The mounting structure for a knee airbag according to claim 1 or 2, The protrusion or the insertion hole is formed near the upper end of the flange portion, The clamping wall extends downward from a position above the upper end of the flange portion, A mounting structure for a knee airbag, characterized in that.

4. The mounting structure for a knee airbag according to claim 1, The mounting structure for a knee airbag, characterized in that the protrusion has a cross-shaped cross section.

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