JP7472838B2 - Airbag cover - Google Patents

Description

The present invention relates to an airbag cover that has a base material and a skin layer bonded to the surface side of the base material, covers a folded airbag, and forms a projection opening when the airbag inflates, allowing the airbag to project.

Conventionally, airbag covers have been configured to have a linear tear portion disposed on the back side of a substrate to which a skin layer is adhered on the front side, and to break this tear portion when the airbag inflates, thereby opening a door portion formed by the peripheral portion of the tear portion, thereby allowing the airbag to protrude from the protrusion opening (see, for example, Patent Document 1). In some cases, this type of airbag cover uses a skin layer with high breaking strength to improve the design of the interior of the vehicle, and even when a skin layer with high breaking strength is used, there is room for improvement in terms of smoothly breaking the skin layer when the tear portion breaks, and quickly forming the protrusion opening.

In addition, some airbag covers have a structure in which a protrusion is provided on the surface side (skin layer side) of the base material to serve as a starting point for fracture in order to cause stress concentration in the skin layer when the tear portion breaks (see, for example, Patent Document 2).

JP 2020-157840 A JP 2004-352179 A

However, in the airbag cover described in Patent Document 2, the surface of the base material facing the skin layer is configured to have protruding ridges that protrude partially. Although the skin layer can be smoothly torn from these protruding ridges, there is room for improvement in terms of making the surface of the skin layer smooth and improving the design.

The present invention aims to solve the above-mentioned problems by providing an airbag cover that has a good design and can quickly form a protrusion opening when the tear portion breaks.

The airbag cover according to the present invention has a base material and a skin layer bonded to the front surface side of the base material, and is configured to cover a folded airbag and form a projection opening by the inflating airbag to allow the airbag to project,
The airbag cover has a base material having a tear portion formed by linearly arranging recesses that reduce the thickness of the base material, and when the tear portion breaks, a door portion formed by a peripheral portion of the tear portion in the base material is opened to form a protrusion opening,
The tear portion is configured to include a fracture origin forming portion that forms a fracture origin of the skin layer at the time of fracture, and a general portion that is disposed on both sides of the fracture origin forming portion,
The fracture origin component is characterized in that, in plan view, it is composed of narrow portions formed from general portions on both sides so as to reduce the opening width dimension of the recess.

In the airbag cover of the present invention, when the airbag inflates, the base material breaks the tear portion, and the airbag inflates from the protrusion opening formed by opening the door portion composed of the peripheral portion of the tear portion, and when the tear portion breaks, the skin layer also breaks. At this time, the skin layer is brought into contact with the breakage origin component formed in the tear portion, forming a breakage origin, and the break is propagated from this origin. In the airbag cover of the present invention, the breakage origin component is configured to have a narrow portion with a smaller opening width dimension than the general portions arranged on both sides in a plan view. In other words, it is configured to partially protrude from the general portion in a direction along the substrate surface. Therefore, when the tear portion initially breaks, the tip of the narrow portion (the protruding end that protrudes partially) is brought into contact with the skin layer so as to pierce the surface side from the back side, thereby reliably providing a breakage origin in the skin layer, and the breakage is propagated from the start point to both sides, so that the skin layer can be broken quickly. In addition, in the airbag cover of the present invention, the breakage origin component is configured to have a partially narrow opening width dimension compared to the general portion in a plan view. This makes it possible to prevent the breakage origin component from protruding partially to the surface side (skin layer side) of the substrate, and the surface of the skin layer can be made smooth and good in design.

Therefore, the airbag cover of the present invention has a good design and can quickly form a protrusion opening when the tear portion breaks.

In addition, in the airbag cover of the present invention, if the breakage origin component is configured so that the surface side that is the skin layer side is flat and connected to the general part, the breakage origin component can be reliably prevented from protruding from the surface side of the base material, and the design of the surface side of the skin layer can be further improved, which is preferable.

Furthermore, in the airbag cover configured as above, if the breakage origin component is configured to be located at a position that is approximately the center of the leading edge of the door when the door is open, the tear portion and the skin layer can be broken approximately at the center of the leading edge of the door when the airbag is deployed and inflated, which makes it possible to open the door quickly, which is preferable.

Specifically, as the Tea Department,
The door opening includes a horizontal bar portion that defines the leading end of the opening of the door portion when broken, and vertical bar portions that extend from both ends of the horizontal bar portion so as to cross the horizontal bar portion and define the side edge of the door portion when broken. The breakage origin portion is disposed at a position that is approximately the center of the horizontal bar portion, and
Examples of the external shape when viewed in a plane include an approximately H-shape that allows the door portion to be formed on both sides of the horizontal bar portion, an approximately U-shape that allows the door portion to be formed on one side of the horizontal bar portion, or a double Y-shape that allows the door portion to be formed on both sides of the horizontal bar portion.

Furthermore, in the airbag cover of the above configuration, if the skin layer is configured to have a weak direction and a non-weak direction in terms of the breaking strength along the plane, and is arranged so that the breaking strength in the direction perpendicular to the cross bar portion is weak, then at the initial stage of breaking when the tip of the narrow portion (the protruding end that protrudes partially) pierces and breaks the skin layer, the tip of the narrow portion moves along the weak direction of the skin layer, which makes it possible to break the skin layer smoothly, which is preferable.

1 is a schematic perspective view of an airbag device that uses an airbag cover according to one embodiment of the present invention; FIG. 2 is a schematic vertical cross-sectional view of the airbag device of FIG. 1 . FIG. 2 is a bottom view of the airbag cover according to the embodiment. 10 is a partially enlarged bottom view showing a central portion of a horizontal bar portion in a tear portion provided in the airbag cover of the embodiment. FIG. 4 is a partially enlarged cross-sectional view showing a general portion of a tear portion in the airbag cover according to the embodiment. FIG. FIG. 4 is a partially enlarged cross-sectional view showing a location of a breakage origin forming portion in a tear portion in the airbag cover of the embodiment. 4 is a partially enlarged schematic perspective view showing a portion of a protruding portion that forms a breakage origin component in a tear portion of the airbag cover according to the embodiment. FIG. 4 is a partially enlarged schematic front view showing a portion of a protruding portion that forms a breakage origin component in a tear portion of the airbag cover according to the embodiment. FIG. FIG. 13 is a schematic bottom view showing another example of the tear portion. FIG. 13 is a schematic bottom view showing still another example of the tear portion. FIG. 13 is a partially enlarged schematic bottom view showing a modified example of a fracture origin forming portion that constitutes a tear portion. FIG. 13 is a partially enlarged schematic bottom view showing a further modified example of a fracture origin forming portion that constitutes a tear portion. FIG. 13 is a partially enlarged schematic bottom view showing a further modified example of a fracture origin forming portion that constitutes a tear portion.

An embodiment of the present invention will be described below with reference to the drawings. As shown in Figs. 1 and 2, the airbag cover of the embodiment is disposed on the instrument panel 2 of a vehicle 1 and used in an airbag device 10 for the passenger seat. The instrument panel 2 is disposed on the front side of the front seats of the vehicle 1 and comprises a driver's side portion 2a in front of the driver's seat, a passenger's side portion 2b in front of the passenger's seat, and a central portion 2c on the front side of a center console disposed between the driver's seat and the passenger's seat. The passenger's side portion 2b is configured as a portion of the airbag cover 20 that forms a projection opening 60 to smoothly project the airbag 11 (see Fig. 2) when the airbag 11 is inflated.

2, the airbag device 10 is configured to include an airbag 11 that is folded and stored, an inflator 14 that supplies inflation gas G to the airbag 11, a case 15 that stores and holds the folded airbag 11 and the inflator 14, and an airbag cover 20 that covers the folded and stored airbag 11. The case 15 is connected to the body side of the vehicle 1 by a bracket (not shown). The instrument panel 2 on which the airbag cover 20 is provided is configured so that the vicinity of the outer periphery and the like are held on the body side of the vehicle 1, and a case side portion 41 of the airbag cover 20, which will be described later, is connected to a side wall portion 17 of the case 15.

Although detailed illustration is omitted, the airbag 11 has a generally quadrangular pyramid shape that converges toward the front end when fully inflated, and has an inflow opening 11a on the underside of the front end for allowing the inflation gas G to flow inside. The inflow opening 11a is formed as a circular opening, and the periphery is held down by a retainer 12 disposed in the airbag 11 and attached to the bottom wall portion 16 of the case 15. The retainer 12 is generally quadrangular and has bolts 12a protruding from the four corners, which extend downward. Each bolt 12a penetrates the periphery of the inflow opening 11a of the airbag 11, the bottom wall portion 16 of the case 15, which will be described later, and the flange portion 14c of the inflator 14, which will be described later, and is fastened to a nut 13. The retainer 12 attaches and fixes the airbag 11 and the inflator 14 to the bottom wall portion 16 of the case 15 by means of the bolts 12a and nuts 13.

The inflator 14 has a roughly cylindrical body 14a with a gas outlet 14b at the top for discharging the inflation gas G, and a roughly square plate-shaped flange 14c protruding from the outer periphery of the body 14a.

The case 15 is configured with a bottom wall portion 16 in the shape of a substantially rectangular plate, and a side wall portion 17 in the shape of a substantially square cylinder extending upward from the outer periphery of the bottom wall portion 16. The bottom wall portion 16 is provided with an insertion hole 16a through which the main body portion 14a of the inflator 14 is inserted from below, and through holes (reference numbers omitted) through which the bolts 12a of the retainer 12 penetrate are provided around the periphery of the insertion hole 16a. As described above, the periphery of the inlet opening 11a of the airbag 11 and the flange portion 14c of the inflator 14 are attached and fixed to the bottom wall portion 16 by the bolts 12a and nuts 13 of the retainer 12. The side wall portion 17 is provided with a locking hook 17a for locking into a locking hole 42 in a case side portion 41 of the airbag cover 20, which will be described later. The locking hooks 17a are arranged at the front and rear of the side wall 17, and multiple hooks are arranged side by side in the left-right direction.

The airbag cover 20 is configured to have a base material 21 and a skin layer 50 bonded to the surface side of the base material 21. The base material 21 is made of a synthetic resin such as polypropylene. In addition to the base material 21 and the skin layer 50, the airbag cover 20 is configured to have a connecting member 40 that connects to the case 15 in the passenger side portion 20b. The connecting member 40 is made of a synthetic resin such as polyolefin thermoplastic elastomer (TPO).

The connecting member 40 is configured to include a substantially rectangular cylindrical case side 41 arranged to surround the side wall 17 of the case 15, and a door side 44 connected to the rear side of the base material 21. In the case side 41, a locking hole 42 is formed in the front wall 41a and the rear wall 41b facing each other in the front-rear direction, into which a locking hook 17a formed in the side wall 17 of the case 15 is inserted and locked. In the embodiment, two door side portions 44 (44F, 44R) are arranged on the front-rear direction side in correspondence with door portions 35F, 35R (described later) provided on the base material 21. Specifically, the door sides 44F, 44R are arranged so that they are separated in the front-rear direction, except for the area below the tear portion 22 described later, and the left and right edges are separated from the case side 41 (see FIG. 3), and are welded to the back side of the door parts 35F, 35R of the base material 21. Specifically, a plurality of protruding welded parts 44a are formed on the upper surface of each door side 44F, 44R (see FIG. 4), and each door side 44F, 44R is welded to the back side of the door parts 35F, 35R by vibration welding or the like using the welded parts 44a. In addition, thin hinge parts 45 are arranged near the front wall part 41a and the rear wall part 41b of the case side 41 in the door side parts 44F, 44R so that the door side parts 44F, 44R can be easily bent and opened together with the door parts 35F, 35R.

The base material 21 has a tear portion 22 and door portions 35F, 35R disposed at the location of the connecting member 40. The door portions 35F, 35R are formed from the peripheral portion of the tear portion 22, and in this embodiment, two door portions 35F, 35R are disposed on either side of the horizontal bar portion 30 (described later) in the tear portion 22. In the airbag cover 20 of this embodiment, when the tear portion 22 breaks, the skin layer 50 is broken and the door portions 35F, 35R are opened, forming the protrusion opening 60.

The tear portion 22 is formed by linearly arranging grooves 24 in the base material 21 to reduce the thickness. In the embodiment, as shown in FIG. 3, the tear portion 22 has an approximately H-shaped outer shape in a plan view, and is configured to have a horizontal bar portion 30 that is disposed between the door portions 35F, 35R when broken and forms the leading end side of the opening of the door portions 35F, 35R, and vertical bar portions 31, 31 that extend from both ends of the horizontal bar portion 30 in the front-rear direction and form the side edge sides of the door portions 35F, 35R when broken. The horizontal bar portion 30 is disposed so as to be approximately along the left-right direction when mounted on the vehicle, and the vertical bar portions 31, 31 are disposed so as to be approximately perpendicular to the horizontal bar portion 30 and extend from both ends of the horizontal bar portion 30 in the front-rear direction. Specifically, in the embodiment, the tear portion 22 is formed by arranging grooves 24 (slits) that cut out the entire substrate 21 (throughout the entire thickness direction) except for the fracture origin portion 22b (i.e., in the general portion 22a) (see FIG. 5), and each vertical bar portion 31, 31 is formed by continuously arranging the grooves 24 along the front-rear direction over the entire front-rear direction, while the horizontal bar portion 30 is formed by intermittently arranging the grooves 24 along the left-right direction (see FIG. 3). The horizontal bar portion 30 has end portions 30b, 30c that are arranged on the end side of the vertical bar portions 31, 31 and are connected to the vertical bar portions 31, 31, and a center portion 30a that is arranged on the left-right center side.

The tear portion 22 is configured to include a fracture origin component 22b that constitutes the fracture origin of the skin layer 50 when fractured, and general portions 22a that are arranged on both sides of the fracture origin component 22b. In the embodiment, the fracture origin component 22b is formed only at one location that is approximately the center of the center portion 30a of the horizontal bar portion 30, and the areas on both sides of the fracture origin component 22b in the center portion 30a, the end portions 30b, 30c of the horizontal bar portion 30, and the vertical bar portions 31, 31 are all composed of the general portion 22a. As described above, the general portion 22a is composed of a groove 24 with a constant width that cuts out the entire substrate 21 (cuts out the entire thickness direction) (see FIG. 5). In detail, the groove 24 that constitutes the general portion 22a is formed so that it is slightly narrower toward the surface 21a of the substrate 21.

The fracture origin constituent portion 22b is constituted by narrow portions 25 formed from the general portions 22a on both sides so as to reduce the opening width dimension of the recess in a plan view (when the airbag cover 20 is viewed from above or below). Specifically, in the case of the embodiment, the fracture origin constituent portion 22b is constituted so as to provide a protruding portion 27 formed so as to protrude partially forward from the rear surface 24b (i.e., at least one surface) of the recessed groove 24, thereby forming a partial narrow portion 25 in the recessed groove 24 (see FIG. 4). The protruding portion 27 is constituted so as to have an outer shape in a plan view that is a substantially isosceles triangle shape (in other words, a triangle shape that converges toward the front surface 24a (the other surface) of the recessed groove 24) with a slight gap between the protruding end 27a on the front end side and the front surface 24a of the recessed groove 24 , and the protruding state is constituted so as to gradually increase from the rear surface 21b side to the front surface 21a side of the base material 21. That is, the protruding portion 27 constituting the fracture starting point constituent portion 22b is configured to be inclined with respect to the thickness direction (up-down direction) so that the trajectory of the protruding end 27a protrudes backward toward the front surface 21a side as shown in FIG. 6 when viewed from the left and right sides. Specifically, the trajectory of the protruding end 27a of the protruding portion 27 is configured so that the lower end side on the back surface 21b side is approximately aligned with the rear surface 24b of the concave groove 24. That is, the outer shape of the protruding portion 27 is an approximately triangular pyramid shape that converges toward the lower end side with the upper surface 27b on the front surface 21a side of the substrate 21 as the bottom surface (see FIGS. 7 and 8). More specifically, the protruding portion 27 forming the fracture starting point constituent portion 22b is configured to have an outer shape in a plan view in an approximately isosceles triangle shape with the width dimension of the base side (rear end side) being about twice the amount of protrusion to the front side and the angle on the protruding end 27a side being approximately a right angle (see FIG. 4). Moreover, upper surface 27b of protruding portion 27 is configured to be substantially flush with surface 21a of base material 21 and to be continuous with surface 21a of base material 21 (see FIGS. 6 and 7). That is, fracture origin forming portion 22b is configured such that the surface side facing skin layer 50 is flat and continuous with general portion 22a (specifically, the peripheral portion of groove 24 constituting general portion 22a).

As shown in Figs. 6 and 7, the skin layer 50 is in the form of a sheet including a fabric 51 as a skin arranged on the surface side and a sheet-like cushion layer 52 to which the fabric 51 is adhered. The fabric 51 is a woven fabric using polyester yarn, and in the embodiment, it is formed by weaving warp threads VS and weft threads HS having different breaking strengths, and is configured to have a weak direction and a non-weak direction in terms of breaking strength along a plane. The fabric 51 is arranged on the surface side of the skin layer 50 so that the warp threads VS, which are weaker than the weft threads HS, are perpendicular to the horizontal bar portion 30 in the tear portion 22, and the weft threads HS are aligned with the horizontal bar portion 30. By arranging the fabric 51 in this way, the fabric 51 is arranged along the front-rear direction so that the weak direction is perpendicular to the horizontal bar portion 30 (see Fig. 6), and the breaking strength in the direction perpendicular to the horizontal bar portion 30 of the tear portion 22 is weakened. The cushion layer 52 is formed from a foam material or cushion material made of polypropylene, polyurethane, etc. The skin layer 50 is arranged by being adhered to the entire surface 21a of the base material 21 by an adhesive layer 55.

Next, the manufacture of the airbag cover 20 of the embodiment will be described. First, the fabric 51 is attached to the cushion layer 52, to which adhesive has been applied, by vacuum forming to form the skin layer 50, and then the skin layer 50 is pressed against the base material 21, to which adhesive has been applied on the front surface 21a to form an adhesive layer 55. Next, the tear portion 22 is formed from the back surface 21b side of the base material 21 by end milling or the like, and the door side portions 44F, 44R of the connecting member 40 are welded to the door portions 35F, 35R to form the instrument panel 2 provided with the airbag cover 20.

Then, with the retainer 12 stored inside, the airbag 11 is folded, the folded airbag 11 is wrapped in a wrapping material (not shown) and stored in the case 15. At this time, each bolt 12a of the retainer 12 protrudes downward from the bottom wall portion 16 of the case 15. Next, the main body portion 14a of the inflator 14 is inserted from below into the insertion hole 16a provided in the bottom wall portion 16, each bolt 12a of the retainer 12 is passed through the flange portion 14c of the inflator 14, and nuts 13 are fastened to each bolt 12a, whereby the folded airbag 11 and the inflator 14 can be attached and fixed to the case 15.

Then, the instrument panel 2 is fixed to the vehicle 1, and the locking hook 17a of the case 15 is inserted and locked into the locking hole 42 provided in the case side portion 41 of the airbag cover 20. The lead wire (not shown) for inputting an activation signal extending from a specified control device is connected to the inflator 14, and the airbag device 10 can be mounted on the vehicle 1.

In this airbag device 10, when the inflator 14 is activated after installation in the vehicle, the airbag 11 is inflated by flowing inflation gas G into the airbag 11. When the airbag 11 inflates, the base material 21 of the airbag cover 20 breaks the tear portion 22 and also breaks the skin layer 50, and opens the door portions 35F, 35R formed from the peripheral portion of the tear portion 22, thereby opening the protrusion opening 60, and the airbag 11 is inflated from the protrusion opening 60. At this time, in the airbag cover 20 of the embodiment, the skin layer 50 comes into contact with the breakage origin forming portion 22b formed in the tear portion 22, forming a breakage origin, and the breakage propagates from this origin. In the airbag cover 20 of the embodiment, the breakage origin forming portion 22b is composed of the narrow portion 25 which, in a plan view, has a smaller opening width dimension of the recess than the general portions 22a arranged on both sides thereof. In other words, the breakage origin forming portion 22b is configured to have a protruding portion 27 which partially protrudes from the general portion 22a on the side along the surface 21a of the base material 21. Therefore, when the tear portion 22 initially breaks, the tip of the narrow portion 25 (the protruding end 27a of the protruding portion 27 which partially protrudes) is brought into contact with the skin layer 50 so as to pierce the skin layer 50 from the back side to the front side (see the two-dot chain line in FIG. 7 ), thereby reliably providing a breakage origin in the skin layer 50 (fabric 51) and causing the breakage to propagate from the origin to both sides, thereby quickly breaking the skin layer 50 (fabric 51). In addition, in the airbag cover 20 of this embodiment, the breakage origin component 22b is configured to partially narrow the opening width dimension compared to the general portion 22a in a plan view, so that partial protrusion onto the surface 21a side (skin layer 50 side) of the base material 21 can be suppressed, and the surface of the skin layer 50 can be made smooth, resulting in good design.

Therefore, the airbag cover 20 of this embodiment has a good design and can quickly form the protrusion opening 60 when the tear portion 22 breaks.

In the airbag cover 20 of the embodiment, the breakage origin component 22b is configured so that the surface side facing the skin layer 50 is flat and connected to the general portion 22a. Specifically, the protruding portion 27 constituting the breakage origin component 22b is configured so that the upper surface 27b is substantially flush with the surface 21a of the base material 21 and connected to the surface 21a of the base material 21. This reliably prevents the breakage origin component 22b from protruding from the surface 21a of the base material 21, and further improves the design of the surface side of the skin layer 50.

Furthermore, in the airbag cover 20 of the embodiment, the breakage origin component 22b is disposed at a position that is approximately the center of the leading end side of the door parts 35F, 35R when they are opened (specifically, at the center between the left and right of the center part 30a of the horizontal bar part 30), so that when the airbag 11 is deployed and inflated, the tear part 22 and the skin layer 50 can be broken from approximately the center of the leading end side of the opening of the door parts 35F, 35R, and the door parts 35F, 35R can be opened quickly. If such a point is not taken into consideration, the breakage origin component may be disposed in an area other than the center between the left and right of the horizontal bar part or in the area of the vertical bar part. If stress concentration at the time of breakage is taken into consideration, it is preferable to dispose the breakage origin component at only one location in the tear part.

Furthermore, in the airbag cover 20 of the embodiment, the skin layer 50 is configured to have a weak direction and a non-weak direction in terms of breaking strength along a plane, and is arranged so as to weaken the breaking strength in the direction perpendicular to the horizontal bar portion 30 of the tear portion 22. Specifically, in the airbag cover 20 of the embodiment, the fabric 51 constituting the skin layer 50 is formed by weaving warp threads VS and weft threads HS having different breaking strengths, and the warp threads VS, which are weaker than the weft threads HS, are arranged so as to be perpendicular to the horizontal bar portion 30, thereby weakening the breaking strength in the direction perpendicular to the horizontal bar portion 30 of the tear portion 22. Therefore, when the tear portion 22 breaks, the protruding end 27a of the protruding portion 27 moves along the weakening direction of the skin layer 50 (fabric 51) at the initial stage of breaking when the tip of the narrow portion 25 (the protruding end 27a of the protruding portion 27) pierces and breaks the skin layer 50, so that the skin layer 50 can be broken smoothly. In the embodiment, the fabric 51 is used as the skin arranged on the surface side of the skin layer 50, but the material constituting the skin is not limited to woven fabric, and knitted fabric, synthetic leather, synthetic resin film material, etc. may be used as long as it has a configuration with a weak direction and a non-weak direction. Of course, if the above-mentioned ... is not taken into consideration, fabrics that do not have a difference in breaking strength may be used as the skin constituting the skin layer.

In the embodiment of the airbag cover 20, the tear portion 22 has an external shape that is approximately H-shaped in a plan view. However, examples of the tear portion include a tear portion 22A that is approximately U-shaped, which allows a door portion 35A to be formed on one side of the horizontal bar portion 30A, as shown in FIG. 9, and a tear portion 22B that is double Y-shaped, which allows door portions 35B to be formed on both sides of the horizontal bar portion 30B, as shown in FIG. 10, in which the vertical bar portions 31B arranged on both ends of the horizontal bar portion 30B are inclined relative to the horizontal bar portion 30B so that the ends that are separated from the horizontal bar portion 30B are spaced apart from each other.

In addition, in the airbag cover 20 of the embodiment, the outer shape of the narrow portion 25 that forms the fracture origin forming portion 22b in the tear portion 22, i.e., the outer shape of the protrusion portion 27, is configured in a plan view (when the airbag cover 20 is viewed from above or below) so that the width dimension of the base side (rear end side) is set to approximately twice the amount of protrusion toward the front, and the angle on the protruding end 27a side is approximately a right angle, forming an approximately isosceles triangle shape. The external shape of this narrow portion 25 (protrusion portion 27) is not limited to the embodiment, so long as it is a shape that reduces the opening width dimension of the recess from the general portions 22a on both sides. For example, as shown in Figures 11 and 12, protrusion portions 27A, 27B having an approximately isosceles triangular shape in a plan view with an obtuse or acute angle on the protruding end 27a side are formed to protrude from the rear surface 24b of the grooves 24A, 24B, and narrow portions 25A, 25B may be formed from the area between the protrusion portions 27A, 27B and the front surface 24a of the grooves 24A, 24B. Furthermore, as shown in Figure 13, protrusion portions 27C, 27C having an approximately isosceles triangular shape in a plan view may be formed to protrude from the front surface 24a and rear surface 24b of the groove 24C, and narrow portion 25C may be formed from the area between the protrusion portions 27C, 27C. In the embodiment of the airbag cover 20, the protruding portion 27 that constitutes the narrow portion 25 is configured to protrude more toward the surface 21a of the base material 21, but the protruding portion may be constant in the thickness direction of the base material without changing the amount of protrusion.

In the embodiment of the airbag cover 20, the grooves 24 constituting the tear portion 22 are configured as slits that cut through the base material 21 over the entire thickness direction, but the grooves may be formed by not cutting through the base material over the entire thickness direction, but by recessing it from the back side to the front side. Furthermore, in the embodiment, the grooves 24 are arranged intermittently in the horizontal bar portion 30 and continuously in the vertical bar portion 31, but the grooves may be arranged intermittently over the entire tear portion, or may of course be arranged continuously.

In the embodiment of the airbag cover 20, the skin layer 50 is adhered to the entire surface 21a of the base material 21 by the adhesive layer 55, but it may be adhered only partially to the surface of the base material.

2...instrument panel, 10...airbag device, 11...airbag, 14...inflator, 20...airbag cover, 21...base material, 21a...surface, 21b...back, 22, 22A, 22B...tear portion, 22a...general portion, 22b...fracture origin portion, 24, 24A, 24B, 24C...groove, 25, 25A, 25B, 25C...narrow portion, 30, 30A, 30B...horizontal bar portion, 31, 31A, 31B...vertical bar portion, 35F, 35R, 35A, 35B...door portion, 50...skin layer, 51...fabric (skin), 60...projection opening, HS...weft thread, VS...warp thread.

Claims (6)

The airbag is configured to cover a folded airbag, the airbag having a base material and a skin layer bonded to a surface side of the base material, and the airbag is configured to protrude by forming a protrusion opening by the airbag being inflated,
The airbag cover has a structure in which a tear portion is formed in the base material by linearly arranging recesses that reduce the thickness of the base material, and when the tear portion is broken, a door portion formed by a peripheral portion of the tear portion in the base material is opened to form the protrusion opening,
The tear portion is configured to include a fracture origin forming portion that forms a fracture origin of the skin layer at the time of fracture, and a general portion that is disposed on both sides of the fracture origin forming portion,
The fracture origin constituent portion is composed of narrow portions formed so as to reduce an opening width dimension of the recess from the general portions on both sides in a plan view ,
the narrow portion is provided by disposing a protruding portion formed so as to partially protrude from at least one surface of the recess,
The airbag cover is characterized in that the protruding portion has an outer shape in a plan view of a triangular shape that converges toward the other surface side of the recess. The airbag cover according to claim 1, characterized in that the surface side of the fracture origin component that is the skin layer side is flat and connected to the general part. The airbag cover according to claim 1 or 2, characterized in that the breakage origin component is disposed at a position that is approximately the center of the tip side of the door when the door is opened. The tear portion is
The door opening includes a horizontal bar portion that constitutes the leading end side of the opening of the door portion when broken, and vertical bar portions that extend from both ends of the horizontal bar portion so as to cross the horizontal bar portion and constitute the side edge side of the door portion when broken. The breakage origin constituent portion is disposed at a position that is approximately the center of the horizontal bar portion, and
4. The airbag cover according to claim 1, wherein the outer shape in a plan view is configured as either an approximately H-shape, which enables the door portion to be formed on both sides of the horizontal bar portion, an approximately U-shape, which enables the door portion to be formed on one side of the horizontal bar portion, or a double Y-shape, which enables the door portion to be formed on both sides of the horizontal bar portion. The airbag cover according to claim 4, characterized in that the skin layer is configured to have a weak direction and a non-weak direction in terms of breaking strength along a plane, and is arranged so that the breaking strength is weak in the direction perpendicular to the cross bar portion. The airbag cover according to claim 1 or 2, characterized in that the protruding portion is configured such that the trajectory of the protruding end is inclined with respect to the thickness direction of the base material when viewed from the side, so that the protruding state gradually increases from the back side to the front side of the base material.

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