JP7574784B2 - Airbag cover - Google Patents

Description

The present invention relates to an airbag cover that is used in an airbag device equipped with an airbag that inflates to protect an occupant, covers the folded airbag, and forms a projection opening to allow the airbag to project when the airbag inflates.

Conventionally, an airbag cover arranged on a vehicle's instrument panel has a door section that opens when pushed by the airbag when the airbag inflates to form an opening for the airbag to protrude, and further includes a base material made of synthetic resin such as polypropylene arranged in an area including the door section, and a retainer made of synthetic resin such as an olefin-based thermoplastic elastomer that is softer than the base material arranged in the area where the door section is arranged, and the base material and the retainer are integrally molded by two-color molding using molding materials (see, for example, Patent Document 1). In this airbag cover, the door section includes a door component of the base material and a door support portion that is provided on the retainer and holds the door component. The retainer includes a door support portion, a peripheral portion arranged around the door support portion, and a hinge portion arranged between the peripheral portion and the door support portion and bent when the door section is opened. Unlike the conventional configuration (see Patent Document 2) in which the base material and the retainer are formed separately and then vibration welded, this airbag cover is a two-color molded product, and furthermore, the hinge portion of the retainer is not configured to be curved so as to be bulky, but is configured to be approximately flat to ensure flexibility. This hinge portion is a thin, approximately flat plate that is joined to the back side of the base material.

JP 2009-248610 A (see FIGS. 1 and 2) JP 2009-248610 A (see FIGS. 3 and 4)

However, in the airbag cover described in Patent Document 1, although the hinge portion of the retainer is thin and ensures flexibility, it is connected to the corresponding portion of the hinge portion in the base material by two-color molding, and when the door portion is opened, the portion of the base material is also bent, so there is room for improvement in terms of further improving the opening performance of the door portion.

The present invention aims to solve the above-mentioned problems and provide an airbag cover that can improve the opening performance of the door section.

The airbag cover according to the present invention is configured to have a door portion that is pushed open by the airbag when the airbag is inflated so as to form an opening for the airbag to protrude therethrough,
A synthetic resin base material disposed in an area including the door portion;
a retainer made of a synthetic resin that is softer than the base material and is joined to the back side of the base material in the area where the door portion is disposed,
The door portion is configured to include a door constituent portion of the base material and a door support portion provided on the retainer to hold the door constituent portion,
the retainer is configured to include the door support portion, a peripheral portion disposed around the door support portion, and a substantially flat hinge portion disposed between the peripheral portion and the door support portion and capable of bending when the door portion is opened,
an airbag cover body including the base material and the retainer;
a surface layer that is bonded to a surface side of the airbag cover body and has flexibility that allows it to be broken when the door part is opened;
The present invention is configured to include
the base material is provided with a space portion at a position where the hinge portion of the retainer is disposed, the space portion being a non-disposition portion of the base material;
The hinge region is characterized by being composed of two layers: the hinge portion of the retainer and the skin layer bonded to the hinge portion.

In the airbag cover according to the present invention, the hinge portion when the door is opened is not provided with a base material as a non-disposed portion of the base material with a space provided, and is composed of two layers: a flexible skin layer and a hinge portion of a retainer made of a synthetic resin that is softer than the base material. Therefore, since the base material itself is not bent when the door is opened, the hinge portion bends smoothly and the door opens. In addition, the skin layer is disposed on the surface of the airbag cover body made of the base material and the retainer, including the hinge portion, and the base material, including the space portion, is not exposed on the surface side, improving the design of the airbag cover.

Therefore, the airbag cover of the present invention can improve the door opening performance and improve the design.

In the airbag cover according to the present invention, it is preferable that the door portion is made up of three layers, arranged from the outer surface side, including the skin layer, the door component of the base material, and the door support part of the retainer.

In this configuration, the door section is configured such that the substrate is disposed on the back side of the surface skin layer on the front side, just like the general area of the airbag cover excluding the area where the door section is located, i.e., the general area where the retainer is not provided, and the surface skin layer of the door section is supported by the substrate on the back side, so that the feel of the door section can be made equivalent to the feel of the general area.

In the airbag cover according to the present invention, a breakable portion that is pushed by the inflating airbag and breaks is provided around the door portion except for the area where the hinge portion is provided,
It is desirable that the portion to be broken be made up of two layers, that is, the skin layer and the base material having a fragile portion provided thereon, as a portion where the retainer is not provided.

In this configuration, the breakable portion that breaks when the door is opened is configured without a retainer, so the breakable portion that is pushed open by the inflating airbag is made up of only two layers: a breakable skin layer and an easily breakable base material with a fragile portion. This allows the breakable portion to break smoothly when the door is opened, stabilizing the opening performance of the door.

In addition, in the airbag cover according to the present invention, it is preferable that the retainer is configured by providing a connecting wall portion on the peripheral portion, which is connected to a mounting base of an airbag device that holds the folded airbag.

In this configuration, the area where the door portion of the airbag cover is located is connected to the mounting base that holds the folded airbag in the airbag device via a connecting wall extending from the peripheral portion of the retainer. Therefore, when the airbag inflates, the peripheral portion of the retainer is connected to the mounting base of the airbag device and does not move away from the mounting base. This allows the door portion, which is connected to the peripheral portion of the retainer via a hinge portion, to accurately receive the pressing force of the inflating airbag and open quickly.

Furthermore, in the airbag cover according to the present invention, it is preferable that a portion formed of three layers, the skin layer, the base material, and the retainer, is disposed in the outer area of the hinge portion in the area where the door portion is disposed.

In this configuration, even if the hinge portion of the retainer is not connected to the base material of the airbag cover body, the peripheral portion of the retainer is connected to the base material. Even if a strong tensile force is applied to the hinge portion of the retainer when the door portion is opened, the peripheral portion near the hinge portion of the retainer is connected to the base material and is prevented from peeling off from the base material. Therefore, the door portion can be opened smoothly while bending the hinge portion (hinge portion of the retainer) without affecting the skin layer of the general area of the airbag cover where the retainer is not provided.

In the airbag cover according to the present invention, it is preferable that the airbag cover body is integrally formed by two-color molding using the molding material of the base material and the retainer.

In this configuration, compared to forming the base material and the retainer separately and then bonding them by vibration welding or the like to form the airbag cover body, or forming the airbag cover body by insert molding, the mold costs and labor are reduced and the airbag cover body can be formed efficiently, which contributes to reducing the labor and costs required to manufacture the airbag cover.

1 is a schematic perspective view of an airbag device using an airbag cover according to an embodiment of the present invention; 1 is a schematic longitudinal sectional view of an airbag device according to an embodiment of the present invention taken along a front-rear direction. 2 is a schematic enlarged partial longitudinal sectional view of the airbag device according to the embodiment taken along a front-rear direction. FIG. 1 is a schematic longitudinal sectional view taken along the left-right direction of an airbag device according to an embodiment of the present invention; 4 is a plan view of the airbag cover according to the embodiment, showing an area in which a door portion is provided. FIG. 4 is a bottom view of the airbag cover according to the embodiment, showing the vicinity of an area where a door portion is provided. FIG. FIG. 4 is a bottom view showing a portion of a substrate to be broken according to an embodiment. FIG. 8 is a schematic enlarged bottom view showing the vicinity of the fracture initiation site of the portion to be fractured in the substrate of the embodiment, which corresponds to the VIII site in FIG. 7, and also shows a schematic cross-sectional view of the vicinity of that site. FIG. 4 is a schematic enlarged bottom view showing the vicinity of a break initiation site of a portion to be broken in a substrate according to an embodiment. FIG. 8 is a schematic enlarged bottom view showing the vicinity of a side edge of a door portion in a base material of the embodiment, corresponding to the portion X in FIG. 7, and also shows a schematic cross-sectional view of the vicinity of that portion. 1A to 1C are diagrams for explaining the manufacturing process of the airbag cover according to the embodiment, showing the process of manufacturing the base material. 1A to 1C are diagrams for explaining the manufacturing process of the airbag car according to the embodiment, showing the process of manufacturing the retainer. 13 shows a step of manufacturing a retainer subsequent to the step shown in FIG. 12, and further shows a step of adhering a skin layer. 4 is a schematic enlarged vertical cross-sectional view illustrating the airbag cover according to the embodiment when a door portion is initially opened. FIG. 13 is a schematic longitudinal sectional view taken along the left-right direction of an airbag device using an airbag cover according to a modified example. FIG. 16 is a plan view of the base material in the vicinity of the area in which the door portion of the airbag cover shown in FIG. 15 is disposed. FIG.

An embodiment of the present invention will be described below with reference to the drawings. The airbag cover 20 of the embodiment is disposed on the instrument panel 2 of a vehicle 1 and used in an airbag device 10 for a passenger seat, as shown in Figs. 1 to 4. The instrument panel 2 is disposed below the front windshield 1a in front of the front seats of the vehicle 1, and is configured with a driver's seat side portion 2a in front of the driver's seat, a passenger seat side portion 2b in front of the passenger seat, and a central portion 2c in front of a center console (not shown). The passenger seat side portion 2b is configured as a portion of the airbag cover 20 that forms a projection opening 68 that is a substantially rectangular opening so that the airbag 11 (see Fig. 2) can smoothly project when the airbag 11 is inflated.

2 and 4, the airbag device 10 is configured to include an airbag 11 that inflates to protect a passenger in the front passenger seat by introducing inflation gas G, an inflator 14 that supplies inflation gas G to the airbag 11, an airbag cover 20 that covers the folded and stored airbag 11, and a mounting base 15 that stores and holds the folded airbag 11 and the inflator 14. The mounting base 15 is connected to the body side of the vehicle 1 by a bracket (not shown). The instrument panel 2 provided with the airbag cover 20 is held near the outer periphery and the like on the body side of the vehicle 1, and is connected to the mounting base 15 at the portion of the airbag cover 20 by using a connecting wall portion 53 described later.

The airbag 11 is made of woven fabric such as polyester, and when fully inflated, has a generally rectangular truncated pyramid shape tapering toward the front with a receiving surface at the rear end for receiving a passenger in the front seat, and is provided with an inlet opening 11a on the underside of the front end for allowing the inflating gas G to flow in. The inlet opening 11a opens in a circular shape, and the periphery of the inlet opening 11a is held down by a generally rectangular annular retainer 12 disposed within the airbag 11, and is attached to the bottom wall 16 of the mounting base 15. The retainer 12 has bolts 12a protruding from the four corners of the generally rectangular annular shape, extending downward. Each bolt 12a passes through the periphery of the inlet opening 11a of the airbag 11, the bottom wall portion 16 of the mounting base 15 (described later), and the flange portion 14c of the inflator 14 (described later), and fastens the nut 13 to the bottom wall portion 16 of the mounting base 15, thereby attaching and fixing the airbag 11 and the inflator 14 to the bottom wall portion 16 of the mounting base 15.

The inflator 14 is generally cylindrical and includes a main body 14a with a gas outlet 14b at the top for discharging the inflation gas G, and a flange 14c that protrudes from the outer periphery of the main body 14a and through which the bolts 12a of the retainer 12 pass.

The mounting base 15 is made of sheet metal and includes a bottom wall 16 in the shape of a substantially rectangular plate and a side wall 17 in the shape of a substantially square cylinder extending upward from the outer periphery of the bottom wall 16. The bottom wall 16 is provided with an insertion hole 16a through which the main body 14a of the inflator 14 is inserted from below, and through holes (not shown) through which the bolts 12a of the retainer 12 penetrate are provided around the insertion hole 16a. The periphery of the inlet opening 11a of the airbag 11 and the flange 14c of the inflator 14 are attached and fixed to the bottom wall 16 of the mounting base 15 by the bolts 12a and nuts 13 of the retainer 12. The side wall 17 is provided with a locking hook 17a that is engaged with a locking hole 54 provided in the connecting wall 53 of the retainer 50. 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.

As shown in Figures 1 to 6, the airbag cover 20 has door sections 24 (F, B) that are pushed open by the airbag 11 to form a protrusion opening 68 for the airbag 11 when the airbag 11 inflates. The door sections 24 (F, B) are configured to open to form the protrusion opening 68, which has a generally rectangular opening shape similar to the bottom wall section 16 of the mounting base 15 of the airbag device 10. The door sections 24F, 24B in this embodiment are configured to open like double doors on both the front and rear sides, and when opened, open the areas that divide the protrusion opening 68 into the front and rear halves.

The airbag cover 20 is also configured with a door installation area 22 in which the door sections 24 (F, B) are arranged, and a surrounding general section 21. The door installation area 22 is configured with the door sections 24F, 24B themselves, their hinge parts 25, a breakable section 27 for breaking the periphery of the door sections 24F, 24B to open the door sections 24F, 24B, and a peripheral section 51 area of the retainer 50, which will be described later. The breakable section 27 is arranged on the periphery of the door sections 24F, 25B that open on both the front and rear sides, and is arranged in a roughly H-shape when viewed from above, with a horizontal line section 28 extending in the left-right direction at the boundary section between the front and rear door sections 24F, 25B, and vertical line sections 29 (L, R) extending in the front-rear direction on both the left and right sides of the horizontal line section 28.

The airbag cover 20 further comprises an airbag cover body 31 and a skin layer 62 that is adhered to the surface side of the airbag cover body 31.

The airbag cover body 31 is configured with a base material 32 made of synthetic resin such as polypropylene arranged in an area including the door parts 24 (F, B), and a retainer 50 made of synthetic resin such as an olefin-based thermoplastic elastomer that is softer than the base material 32 and arranged so as to be joined to the back surface 32b side of the base material 32 in the arrangement area 22 of the door parts 24 (F, B). In the case of the embodiment, the airbag cover body 31 is configured as a two-color molded product integrally molded by two-color molding using the molding materials of the base material 32 and the retainer 50.

The base material 32 and skin layer 62 of the airbag cover body 31 extend not only to the passenger side 2b, which is the area of the airbag cover 20 of the instrument panel 2, but also to the driver side 2a and central portion 2c. In other words, the general portion 21 of the airbag cover 20 is composed of the base material 32 and skin layer 62 of the airbag cover body 31, and is arranged so as to extend to the driver side 2a and central portion 2c of the instrument panel 2.

The door sections 24F, 24B of the airbag cover 20 are each configured with a door component 35F, 35B of the base material 32 and a door support section 58F, 58B that is provided on the retainer 50 and is connected to the door component 35F, 35b so as to hold the respective door component 35F, 35B from the back side. Furthermore, a door skin section 66 of the skin layer 62 is bonded and disposed on the front side of each door component 35F, 35B.

The skin layer 62 is composed of a fabric 63 as a skin arranged on the surface 62a side, and a sheet-like cushion layer 64 to which the fabric 63 is adhered. The fabric 63 is a woven fabric made of warp and weft threads such as polyester. The cushion layer 64 is made of a cushioning material such as polypropylene. The skin layer 62 is composed of a door skin portion 66 arranged on the surface side of each door section 24F, 24B, and a general portion 65 surrounding the door skin portion 66. The boundary between the periphery of the door skin portion 66 and the general portion 65 is arranged in the area of the breakable portion 27, and is broken when the door section 24 (F, B) is opened.

The retainer 50 is configured to include the door support portion 58 (F, B) described above, a peripheral portion 51 disposed around the door support portion 58 (F, B), and a thin, substantially flat hinge portion 60 (F, B) disposed between the peripheral portion 51 and the door support portion 58 (F, B) to connect the peripheral portion 51 and the base portion 58b of each door support portion 58 (F, B) and bendable when the door portion 24 (F, B) is opened. The retainer 50 has gaps 56 corresponding to the breakable portion 27 between the peripheral portion 51 and the inner side of the peripheral portion 51 and the peripheral portion 51 of the door support portion 58F and the hinge portion 60F, and between the peripheral portion 51 and the inner side of the peripheral portion 51 of the door support portion 58B and the hinge portion 60B. That is, the gap 56 is generally H-shaped when viewed from above, with a horizontal bar portion 56a corresponding to the horizontal line portion 28 of the intended break portion 27, and vertical bar portions 56b (L, R) corresponding to the left and right vertical line portions 29 (L, R) of the intended break portion 27 (see FIG. 6).

In the embodiment, the base material 32 has a space 47 (F, B) at the location of the hinge portion 60 (F, B) of the retainer 50, and the hinge portion 60 (F, B) is a non-location portion where the base material 32 is not located. Therefore, in the airbag cover 20, the hinge portion 25 of the door portion 24 (F, B) is the area of the hinge portion 60 (F, B) of the retainer 50, and is composed of two layers: the hinge portion 60 (F, B) of the retainer 50 and a skin layer 62 bonded to the hinge portion 60 (F, B).

The peripheral portion 51 of the retainer 50 is configured as a generally rectangular ring-shaped portion disposed around the periphery of the protrusion opening 68, and includes a flange portion 52 extending outward from the upper end of the downwardly extending rectangular cylindrical connecting wall portion 53. The flange portion 52 is configured of a front flange portion 52a, a rear flange portion 52b, a left flange portion 52c, and a right flange portion 52d, which are disposed on the front, rear, left and right sides of the connecting wall portion 53. The peripheral portion 51 is also configured with inner protrusion portions 52ca, 52da that extend inward from the left wall portion 53c and the right wall portion 53d on the left and right sides of the connecting wall portion 53, which will be described later.

The front wall 53a and rear wall 53b of the connecting wall 53 of the retainer 50 are formed with locking holes 54 into which the locking hooks 17a of the mounting base 15 of the airbag device 10 are inserted (see Figure 2).

The base material 32 is configured to include a door installation area 34 disposed in the door installation area 22 of the airbag cover 20, and a general portion 33 disposed in the general portion 21 of the airbag cover 20 around the door installation area 34. The door installation area 34 is configured from door components 35 (F, B), rectangular opening spaces 47 (F, B) disposed on the base portion 35b side of each door component 35, fragile portions 36 disposed on the tip edge 35a and side edge 35d of each door component 35F, 35B and constituting the intended breakage portion 27, and a peripheral connection portion 48 connected to the peripheral portion 51 of the retainer 50 (see FIG. 7).

The peripheral joint 48 is configured with a front side portion 48a that is joined to the front side flange 52a of the flange 52 of the peripheral portion 51, a rear side portion 48b that is joined to the rear side flange 52b, a left side portion 48c that is joined to the left side flange 52c, and a right side portion 48d that is joined to the right side flange 52d. The left side portion 48c and the right side portion 48d on the left and right sides extend up to the vertical bar portions 56bL and 56bR of the gap 56 of the retainer 50, and are provided with inner protrusions 48ca and 48da that are disposed near the left and right side edges 35d of the door components 35F and 35R (see Figures 2, 3, 6, and 7). The inner protrusions 48ca, 48da are configured to connect to the inner protrusions 52ca, 52da of the retainer 50 on the lower side of a portion of the weak portion 36.

The fragile portion 36 constituting the intended rupture portion 27 is configured by arranging a plurality of band-shaped rupture openings 37 along the horizontal line portion 28 and vertical line portion 29 (L, R) of the approximately H-shaped intended rupture portion 27, and a plurality of rupture connection portions 41 (A, B), 45 arranged to close the spaces between the rupture openings 37 and rupture when the airbag 11 is inflated (see Figures 5 and 7).

Fracture connecting parts 41 (A, B) are arranged at the horizontal line parts 28 of the intended fracture part 27 so as to close the fracture opening 37 (see Figures 8 and 9), and fracture connecting parts 45 are arranged at the vertical line parts 29 (L, R) so as to close the fracture opening 37 (see Figure 10).

In this embodiment, the vicinity of the center portion 28a in the left-right direction of the horizontal line portion 28 is the starting point for breakage when the door portion 24 (F, B) is opened.

The breakable connecting parts 41 (A, B) disposed on the horizontal line part 28 are disposed such that the width dimension in plan view between adjacent breakable openings 37, 37 is smaller on the separated tip end 41b side than on the base part 41a side, which is the tip edge 35a side of the front door component 35F (see Figures 8 and 9). That is, the breakable connecting parts 41 (A, B) are arranged such that the width dimensions W11, W21 of the front base part 41a are wider than the width dimensions W12, W22 of the rear tip end 41b in plan view.

In this embodiment, 14 breakable connecting parts 41 (A, B) are arranged on the horizontal line part 28, with four breakable connecting parts 41A arranged in the area near the central part 28a, and five breakable connecting parts 41B arranged on each side, which are offset from the area near the central part 28a.

The breakable connecting portion 41A near the central portion 28a has an intersection angle θA on the tip end 41b side between the widthwise (left-right) side edges 42, 43 of the adjacent breakable openings 37, 37 and the opposing edges 38, 39 that face each other in the front-to-rear direction of the breakable opening 37, which is an acute angle (approximately 60° in this embodiment).

As shown in FIG. 9, the breaking connection portion 41B on the vertical line portion 29 (L, R) side that is offset to the left and right from the left-right central portion 28a of the horizontal line portion 28 has an acute intersection angle θB at the rear end portion 41b (door portion 24B side) between the widthwise (left-right) side edges 42, 43 of the adjacent breaking openings 37, 37 and the opposing edges 38, 39 that face each other in the front-rear direction of the breaking opening 37, but is larger than that of the breaking connection portion 41A (approximately 75° in the embodiment).

The thickness dimension Bt2 of the base material 32 is approximately 3 mm, the opening width dimension H0 of the breaking opening 37 is approximately 1 mm, the width dimension W11 of the base portion 41a of the breaking connection portion 41A is approximately 4.2 mm, the width dimension W12 of the tip portion 41b is approximately 3 mm, the width dimension W21 of the base portion 41a of the breaking connection portion 41B is approximately 4.54 mm, and the width dimension W22 of the tip portion 41b is approximately 4 mm.

The breakable joints 45 arranged on the vertical line portions 29 (L, R) are arranged to close the gap between the adjacent breakable openings 37, but are drum-shaped in plan view, with the side edges 45d, 45e on the breakable opening 37 side being semicircular, and the base 45a on the door components 35F, 35B side and the tip 45b on the left side 48c and right side 48d side of the peripheral joint 48 being symmetrical (see FIG. 10). Two drum-shaped breakable joints 45 are arranged on each of the left and right side edges 35d of the door components 35F, 35B, and when the airbag 11 breaks due to inflation, the vicinity of the narrow intermediate portion 45c between the base 45a on the door component 24 (F, B) side and the tip 45b on the side away from the door component 24 (F, B) breaks. The width dimension W3 of the middle portion 45c is approximately 3 mm.

The vertical line portions 29 (L, R) are arranged such that the front side is disposed on the side edge 35d side of the front door component 35F and the rear side is disposed on the side edge 35d side of the rear door component 35B. In the central portion 29a in the front-rear direction, the break opening 37 extends from the break connecting portion 41 on the horizontal line portion 28 side in a Y-shaped bifurcated shape to both the front and rear, and is formed so that the break opening 37 extends forward and backward, with the break connecting portion 45 interposed therebetween (see Figures 5 and 7).

The front and rear door components 35 (F, B) of the base material 32 have a base portion 35b on the space portion 47 (F, B) side that is a tapered portion 35c that becomes thinner toward the space portion 47 (F, B) side (see Figures 2 and 3), and the tip edge 35a side is flat and has the same thickness dimension across the horizontal line portion 28 of the intended break portion 27 in the fragile portion 36. Except for the tapered portion 35c in the base material 32, the thickness dimension Bt2 of the door arrangement area 34 of the door components 35 (F, B) and the peripheral joint portion 48 is approximately 3 mm, which is the same as the thickness dimension Bt1 of the general portion 33.

In addition, the retainer 50 has a thickness dimension Rt1 of the flange portion 52 of approximately 4 mm, a thickness dimension Rt2 of the door support portion 58 (F, B) of approximately 2 mm, and a thickness dimension Rt3 of the hinge portion 60 (F, B) of approximately 1 mm within the range of approximately 0.5 to 1.5 mm (see Figure 3).

The thickness dimension St0 of the skin layer 62 is approximately 2.6 mm.

When manufacturing the airbag cover 20, first the airbag cover main body 31 is molded. As shown in Figures 11 to 13, the molding die 70 can be two-color molded using molding materials M1, M2 for the base material 32 and the retainer 50, and is configured with split dies 73, 74 capable of molding the base material 32, and split die 75 which can mold the retainer 50 by sharing the split die 73. When the split dies 73, 74 are closed, a cavity 71 capable of molding the base material 32 is formed from their mold surfaces 73a, 74a, and the base material 32 can be formed by injecting a specified molding material M1 into the cavity 71 and solidifying it. Then, the mold is opened, and with the base material 32 held on the split mold 73 side, the split mold 74 is replaced with the split mold 75, and the split molds 73, 75 are clamped to form a cavity 72 in which the retainer 50 can be molded from the mold surfaces 73a, 75a. If a predetermined molding material M2 is injected into the cavity 72 and allowed to solidify, the retainer 50 can be formed in a state bonded to the base material 32. Then, the mold is opened while sliding the slide cores 77, 78, and the airbag cover main body 31, which has been molded into a two-color product, is taken out, and the skin layer 62 is attached, thereby manufacturing the airbag cover 20.

The fragile portion 36 of the base material 32 that forms the intended break portion 27 and the space portion 47 (F, B) are integrally formed when the base material 32 is molded using the split molds 73, 74.

To assemble the airbag device 10 using the airbag cover 20 manufactured in this manner, first, with the retainer 12 stored inside the airbag 11, the airbag 11 is folded, the folded airbag 11 is wrapped in a wrapping material (not shown), and the airbag 11 is stored in the mounting base 15. At this time, each bolt 12a of the retainer 12 protrudes downward from the bottom wall portion 16 of the mounting base 15. Next, the main body portion 14a of the inflator 14 is inserted from below into the insertion hole 16a of the mounting base 15, each bolt 12a of the retainer 12 is inserted 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 mounting base 15.

Then, the instrument panel 2 is fixed to the body of the vehicle 1, and the locking hook 17a of the mounting base 15 is inserted and locked into the locking hole 54 of the connecting wall portion 53 of the retainer 50 of the airbag cover 20. A lead wire (not shown) for inputting an activation signal extending from a specified control device is connected to the inflator 14. Furthermore, the mounting base 15 is attached and fixed to the body of the vehicle 1 using a specified bracket, and the airbag device 10 can be mounted on the vehicle 1.

In this manner, in the airbag device 10 mounted on the vehicle 1, when the inflator 14 is actuated to discharge the inflation gas G, the airbag 11 inflates by the inflow of the inflation gas G. Then, when the airbag 11 inflates, the airbag cover 20 breaks the breakable connecting parts 41 (A, B), 45 in the weak part 36 of the base material 32 constituting the breakable part 27, and the door part 24 (F, B) bends the hinge part 60 (F, B) of the retainer 50 of the hinge part 25, and is pushed open while breaking the skin layer 62, opening the protrusion opening 68, and the airbag 11 protrudes from the protrusion opening 68 (see the two-dot chain line in FIG. 2).

In the airbag cover 20 of the embodiment, the hinge portion 25 when the door portions 24F, 24B are opened is not provided with the base material 32 as a non-disposed portion of the base material 32 having the space portion 47 (F, B), and is composed of two layers: a flexible skin layer 62 and a hinge portion 60 (F, B) of the retainer 50 made of a synthetic resin softer than the base material 32. Therefore, when the door portions 24F, 24B are opened, the base material 32 itself is not deflected, so the hinge portion 25 is deflected smoothly, and the door portions 24F, 24B are opened. In addition, the skin layer 62 is disposed on the surface of the airbag cover main body 31 made of the base material 32 and the retainer 50, including the hinge portion 25, and the base material 32, including the space portion 47 (F, B), is not exposed to the surface side, improving the design of the airbag cover 20.

Therefore, the airbag cover 20 of this embodiment can improve the opening performance of the door section 24 (F, B) and can also improve the design.

In the embodiment, the base portion 35b of the door component 35 (F, B) of the base material 32 has a tapered portion 35c toward the hinge portion 60 (F, B) of the retainer 50, gradually thinning it to form a space portion 47 (F, B). Therefore, the base material 32, which is harder than the retainer 50, does not impede the bending performance of the hinge portion 60 (F, B) of the retainer 50, and the door portion 24 (F, B) can be opened smoothly.

In the embodiment of the airbag cover 20, the door section 24 (F, B) is composed of three layers, arranged from the outer surface side: the skin layer 62, the door component 35 (F, B) of the base material 32, and the door support section 58 (F, B) of the retainer 50.

Therefore, in the embodiment, the door section 24 (F, B) is configured such that the substrate 32 is disposed on the back side of the surface skin layer 62 on the front side, similar to the area of the general section 21 excluding the area 22 in which the door section 24 (F, B) is disposed in the airbag cover 20, i.e., the area of the general section 21 where the retainer 50 is not provided, and the surface skin layer 62 of the door section 24 (F, B) is supported by the substrate 32 on the back side, so that the tactile feel of the door section 24 (F, B) can be made equivalent to that of the general section 21.

In addition, in the airbag cover 20 of the embodiment, a breakable portion 27 that breaks when pressed by the inflating airbag 11 is disposed around the door portion 24 (F, B) except for the portion where the hinge portion 60 (F, B) is disposed, and the breakable portion 27 is composed of two layers, a skin layer 62 and a base material 32 with a fragile portion 36, as a portion where the retainer 50 is not disposed.

Therefore, in the embodiment, the breakable portion 27 that breaks when the door portion 24 (F, B) is opened is configured without the retainer 50, so that the breakable portion 27 that is pushed open by the inflating airbag 11 is configured with only two layers, the breakable skin layer 62 and the easily breakable base material 32 with the fragile portion 36, so that the breakable portion 27 breaks smoothly when the door portion 24 (F, B) is opened, and the opening performance of the door portion 24 (F, B) can be stabilized.

In the embodiment of the airbag cover 20, the retainer 50 is configured by arranging a connecting wall portion 53 on the peripheral portion 51, which is connected to the mounting base 15 of the airbag device 10 that holds the folded airbag 11.

Therefore, in the embodiment, the arrangement area 22 of the door portion 24 (F, B) of the airbag cover 20 is connected to the mounting base 15 that holds the folded airbag 11 in the airbag device 10 via the connecting wall portion 53 extending from the peripheral portion 51 of the retainer 50. Therefore, when the airbag 11 inflates, the peripheral portion 51 of the retainer 50 is connected to the mounting base 15 of the airbag device 10 and does not move away from the mounting base 15. Therefore, the door portion 24 (F, B) that is connected to the peripheral portion 51 of the retainer 50 via the hinge portion 60 (F, B) can accurately receive the pressing force of the inflating airbag 11 and open quickly.

If the above points are not taken into consideration, the connecting wall portion 53 of the retainer 50 may be connected to surrounding vehicle body components such as the instrument panel hose.

Furthermore, in the airbag cover 20 of the embodiment, the outer area of the hinge portion 60 (F, B) in the arrangement area 22 of the door portion 24 (F, B), i.e., the area of the front flange portion 52a and the rear flange portion 52b, is provided with a portion formed of three layers: the skin layer 62, the base material 32 (the front portion 48a and the rear portion 48b of the peripheral joint portion 48), and the retainer 50 (the front flange portion 52a and the rear flange portion 52b of the peripheral portion 51 of the retainer 50).

Therefore, in the embodiment, even if the hinge portion 60 (F, B) of the retainer 50 is not connected to the base material 32 of the airbag cover body 31, the peripheral portion 51 of the retainer 50 is connected to the base material 32 of the airbag cover body 31. Even if a strong tensile force is applied to the hinge portion 60 (F, B) of the retainer 50 when the door portion 24 (F, B) is opened, the peripheral portion 51 near the hinge portion 60 (F, B) of the retainer 50 (front flange portion 52a and rear flange portion 52b) is not pulled. Because the flange portion 52b) is connected to the base material 32 (front side portion 48a and rear side portion 48b of the peripheral joint portion 48) and is prevented from peeling off from the base material 32, the door portion 24 (F, B) can be opened smoothly while bending the hinge portion 25 (hinge portion 60 (F, B) of the retainer 50) without affecting the skin layer 62 of the general portion 21 area of the airbag cover 20 where the retainer 50 is not provided.

In the airbag cover 20 of the embodiment, when the airbag 11 inflates, the door portion 24 (F, B) is pressed by the expanding airbag 11 at the fragile portion 36 constituting the intended rupture portion 27, breaking the rupture connecting portion 41A near the central portion 28a of the horizontal line portion 28, which is the starting point of the intended rupture portion 27. The rupture connecting portion 41A breaks due to stress concentration on the narrow side of the width dimension W12. At that time, the breaking connecting portion 41A breaks the narrow tip portion 41b side with width dimension W12, leaving behind the wide base portion 41a side with width dimension W11 that is close to the tip edge 35a of the door constituent portion 35F of the front door section 24F. As shown in Figures 14A and 14B, as the door constituent portion 35F as the door section 24F opens, the edge corner 41bb of the front surface 32a of the base material 32 at the fracture surface 41ba on the narrow tip portion 41b side with width dimension W12 is brought into contact with the back surface 62b of the skin layer 62, with the hinge portion 60F as the center of rotation, and pushes up the skin layer 62. That is, as shown in A, B, and C of FIG. 14, while the breaking joint 41A is connected to the leading edge 35a of the door component 35F of the door part 24F, the edge corner 41bb on the leading edge 41b side having a narrow width dimension W12 can bite into the skin layer 62 like a knife protruding from the leading edge 35a of the door component 35F, smoothly breaking the skin layer 62. As a result, as the door component 35F of the base material 32 opens, the skin layer 62 is quickly broken from the leading edge 35a side of the door component 35F, and the breakage is propagated to the periphery of the door component 35F, and the protrusion opening 68 for the airbag 11 is smoothly formed together with the door part 24B (see the two-dot chain line in FIG. 2). And, since the door component 35 does not have a protrusion or the like on the skin layer 62, it does not affect the design of the surface 62a side of the skin layer 62.

Furthermore, in the airbag cover 20 of this embodiment, the break connection portion 41A near the central portion 28a of the horizontal line portion 28, which is the break start portion, connects the end edges 42a, 43a on the tip portion 41b side, which has a smaller width dimension W12 on both edges 42, 43 in the width direction, to the edge 39 on the break opening 37 side to which it is connected, at an acute angle in plan view (see Figures 8 and 9).

Therefore, in the embodiment, if the breaking connection portion 41A near the central portion 28a, which serves as the starting point, is connected to the edge 39 of the adjacent breaking opening at an acute angle on the tip portion 41b side, which narrows the width dimension W12, when it is subjected to the tensile force accompanying the inflation of the airbag 11, stress is smoothly concentrated at that portion, and it is easily broken. In addition, the edges 42a, 43a on the side of the opening 37 for breaking that extend from the broken tip 41b were connected to the edge 39 on the side of the opening 37 for breaking at an acute angle before breaking. Therefore, when breaking occurs, as the tip 41b of the connecting part 41A is pushed up, the edge corner 41bb on the side of the broken end face (fracture surface) 41ba of the tip 41b continues and penetrates the back surface 62b of the skin layer 62, as if pushing it off. This makes it easier for the break to propagate from the breakage point caused by the tip 41b being pushed up, and the skin layer 62 can be broken smoothly from near the center portion 28a, which is the starting point of the breakage, along the intended breakage portion 27.

In addition, in the airbag cover 20 of the embodiment, as shown in FIG. 9, near the central region 28a where the break of the intended break portion 27 starts, the intersection angle θA between the edges 42a, 43a of the narrow tip portion 41b of the side edges 42, 44, which have a width dimension W12, and the edge 39 of the break opening 37 of the break connecting portion 41A is approximately 60°, and the intersection angle θB between the edges 42a, 43a of the narrow tip portion 41b of the side edges 42, 43, which have a width dimension W22, and the edge 39 of the break opening 37 of the break connecting portion 41B away from the central region 28a, is approximately 75°, thereby increasing the degree of acuteness near the central region 28a. Therefore, when the airbag 11 inflates, the vicinity of the central portion 28a in the left-right direction of the horizontal line portion 28, where the breaking connection portion 41A with the sharpened intersection angle θA is located, is more susceptible to stress concentration and breakage than other portions, and breaks accurately as the starting point of breakage, and the door component portion 35 (F, B) of the door portion 24 (F, B) can smoothly rotate the tip edge 35a side around the hinge portion 60 (F, B) to open.

In the embodiment, the intersection angle between the edge 42a, 43a on the tip 41b side of the breaking connection part 41 (A, B) and the edge 39 of the breaking opening 37 is shown as two types of intersection angle θA (approximately 60°) and intersection angle θB (approximately 75°), with the smaller intersection angle θA being positioned on the central portion 28a side which is the starting point of the breakage. However, if the central portion 28a of the horizontal line portion 28 is configured to be the starting point of the breakage, the tip portion 41b of the breaking connection part 41 may be disposed with the same acute intersection angle over the entire horizontal line portion 28. In addition, with regard to the intersection angles θA and θB between the end edges 42a and 43a at the side edges 42 and 43 of the breaking connection part 41 and the edge 39 of the breaking opening 37, as long as at least one of them is an acute angle, they do not have to be equal to each other, and the other may be an obtuse angle close to 90°. Furthermore, as long as both intersection angles θA and θB are acute angles, they do not have to be equal to each other.

In addition, when the acute intersection angle is increased in a stepwise manner as it moves away from the fracture starting point (central portion 28a) as in the embodiment, in addition to being set in two steps as in the embodiment, the intersection angle may be set to be increased in a stepwise manner, starting from the intersection angle near the fracture starting point.

Furthermore, the airbag cover 20 of the embodiment is configured as an airbag cover 20 disposed on the instrument panel 2 in front of the front seats of the vehicle 1, with the wide base portion 41a of the breaking connection portion 41 (A, B) positioned on the front door portion 24F.

Therefore, in the embodiment, when the door parts 24F, 24B open in response to the inflation of the airbag 11, the breakable joints 41A, 41B break the narrow end 41b of the width dimension W12, W22 on the leading edge 35a side of the front door part 24F. In other words, the door parts 24F, 24B open with the breakable joints 41A, 41B connected to the front door part 24F side and the breakable joints 41A, 41B not connected to the rear door part 24b side (see the two-dot chain line in FIG. 2), and the rear door part 24B close to the occupant opens without the breakable joints 41A, 41B connected to the leading edge 35a side when opening (see C in FIG. 14). Therefore, even if the rear door part 24B comes into contact with the occupant when opening, the leading edge 35a side with less unevenness can come into contact.

In the embodiment, the door component 35 (F, B) and the peripheral joint 48 of the base material 32 are connected to the door support 58 (F, B) and the peripheral portion 51 of the retainer 50 in a substantially planar shape. However, to improve the joint strength (adhesion strength) with the retainer 50 near the door component 35 (F, B) of the base material 32, the airbag cover 20C shown in Figs. 15 and 16 may be configured as shown. In this airbag cover 20C, the base material 32C and the retainer 50C are integrally molded by two-color molding using a molding material, and fitting holes 48cb, 48db are formed in the left side portion 48c and the right side portion 48d of the peripheral joint 48C on both the left and right sides of the door component 35 (F, B) of the base material 32C, and fitting protrusions 51a are formed in the peripheral portion 51 of the retainer 50C so as to be fitted into the fitting holes 48cb, 48db. In the airbag cover body 31C of this airbag cover 20C, the base material 32C and the retainer 50C are molded in two colors so that the mating protrusions 51a fit into the mating holes 48cb, 48db. This increases the bonding area (adhesion area) and improves the bonding strength (adhesion strength) of the door support parts 58 (F, B) and the peripheral part 51C of the retainer 50C to the base material 32C.

In addition, in the embodiment of the airbag cover 20, the airbag cover body 31 is integrally formed by two-color molding using the molding material of the base material 32 and the retainer 50.

Therefore, in the embodiment, the airbag cover body 31 can be efficiently formed with reduced mold costs and labor compared to forming the base material 32 and the retainer 50 separately and bonding them by vibration welding or the like to form the airbag cover body, or forming the airbag cover body by insert molding, which contributes to reducing the labor and cost of manufacturing the airbag cover 20. Of course, if this point is not taken into consideration, the base material 32 and the retainer 50 can be formed separately and bonded by vibration welding or the like to form the airbag cover body, or one of the base material 32 or the retainer 50 can be molded first, and the molded product can be used as an insert to form the airbag cover body by insert molding.

In the embodiment, the door portion of the airbag cover is configured to open on both the front and rear sides, but it may be a single door portion that opens forward, etc. Also, the door portion may be a four-door type with the planned breaking portion opening both ends of the horizontal line portion in a Y-shape, for example, two doors on the front and rear sides on both sides of the horizontal line portion, and two doors on the left and right sides surrounded by the Y-shaped planned breaking portion on both sides of the horizontal line portion.

10...airbag device, 11...airbag, 15...mounting base, 20, 20C...airbag cover, 21...general part, 22...door installation area, 24(F,B)...door part, 25...hinge part, 27...proposed breakable part, 31, 31C...airbag cover body, 32, 32C...base material, 32a...surface, 32b...backside, 35(F,B)...door component, 36...weak part, 47(F,B)...space, 48, 48C...periphery joint, 50, 50C...retainer, 51, 51C...periphery, 53...connecting wall, 54...retaining hole, 58(F,B)...door support part, 60(F,B)...hinge part, 62...skin layer, 68...projection opening, M1...molding material (of base material), M2...molding material (of retainer).

Claims (6)

The airbag is configured to have a door portion that is pushed open by the airbag when the airbag is inflated to form an opening for the airbag to protrude therethrough,
A synthetic resin base material disposed in an area including the door portion;
a retainer made of a synthetic resin that is softer than the base material and is joined to the back side of the base material in the area where the door portion is disposed,
The door portion is configured to include a door constituent portion of the base material and a door support portion provided on the retainer to hold the door constituent portion,
the retainer is configured to include the door support portion, a peripheral portion disposed around the door support portion, and a substantially flat hinge portion disposed between the peripheral portion and the door support portion and capable of bending when the door portion is opened,
an airbag cover body including the base material and the retainer;
a surface layer that is bonded to a surface side of the airbag cover body and has flexibility that allows it to be broken when the door part is opened;
The present invention is configured to include
the base material is provided with a space portion at a position where the hinge portion of the retainer is disposed, the space portion being a non-disposition portion of the base material;
An airbag cover, wherein the hinge region is constructed of two layers: the hinge portion of the retainer, and the skin layer bonded to the hinge portion. The airbag cover according to claim 1, characterized in that the door section is composed of three layers, arranged from the outer surface side: the skin layer, the door component of the base material, and the door support part of the retainer. a breakable portion that is broken by being pushed by the inflating airbag is disposed around the door portion except for a portion where the hinge portion is disposed,
3. The airbag cover according to claim 1, wherein the breakable portion is configured from two layers, the surface layer and the base material having a fragile portion, as a portion where the retainer is not disposed. The airbag cover according to any one of claims 1 to 3, characterized in that the retainer is configured by arranging a connecting wall portion on the peripheral portion, which is connected to a mounting base of an airbag device that holds the folded airbag. The airbag cover according to any one of claims 1 to 4, characterized in that a portion formed of three layers, the skin layer, the base material, and the retainer, is disposed in the outer area of the hinge portion in the area where the door portion is disposed. 6. The airbag cover according to claim 1, wherein the airbag cover body is integrally formed by two-color molding using a molding material for the base material and the retainer.

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