JP2006240521A - Airbag door of automobile and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag door not requiring forming a tear line on a skin in an instrument panel having a skin material adhered to a base material. <P>SOLUTION: The tear line of the base material 4 is constituted by a square tear line 21; a central tear line 21b in which an intermediate position between front and rear sides extends in a left/right direction in parallel to the front and rear sides; and side part tear lines of left/right symmetric shape extending to gradually become narrow from the front and rear ends of the left and right sides toward the left and right ends of the central tear line 21b. A square integral hinge part opposed to the square tear line 21 and a slit 32 along the central tear line 21b and the side part tear line are formed on the retainer door part. The left and right sides of the square integral hinge part of the retainer door part 35 are formed to relatively lower strength than the integral hinge part 31 of the front and rear sides such that the skin 11 is broken along the central tear line 21b and the side part tear line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  An airbag door is integrally formed on the instrument panel that is laminated by adhering a skin material with a foam layer to the skin, and the airbag body is held on the door base material portion of the base material. When the flange surrounding the retainer door part of the retainer is joined, the retainer door part is opened when the air bag is activated, and the door base material part breaks and expands along the tear line. The present invention relates to a bag door and a manufacturing method thereof.

  FIG. 7 shows an automobile instrument panel 9 in which an airbag door 7 for a conventional passenger seat of this type is integrally formed. As shown in FIG. 8, for example, a skin made of TPO (thermoplastic olefin) is used. A urethane foam layer 2 is interposed between 1 and the substrate 4 to form three layers. At that time, the door base material portion 4c that breaks and deploys by the operation of the airbag by post-processing includes a thin rectangular tear line (breaking path) 8a, a central tear line 8b that extends left and right at an intermediate position thereof, A double Y-shaped tear line is formed by the side tear line 8c which is gradually narrowed on both sides of the symmetrical shape. Correspondingly, the tear line 1a is formed by post-processing along the center tear line 8b and the side tear line 8c on the skin 1 to which the foam layer 2 is joined. Thus, when the side tear line 8c formed symmetrically and gradually narrowing toward the center part is formed, the door base material with respect to the tear line that completely crosses the center tear line and opens both sides back and forth. The side portions of the portion 4c can be easily deployed without being scattered smoothly.

  On the other hand, according to Patent Document 1, the skin material is flattened with a support and is tension-supported, a three-dimensionally breathable base material is assembled on the convex surface of the vacuum bonding type, and the fabric material is vacuum bonded type Assemble the vacuum-bonding mold of the substrate and the receiving mold assembled with the fabric material from the both sides toward the warming and softening skin material with the support. A method of manufacturing a part-distributed vehicle interior member is disclosed in which a fabric material is pressed and bonded to a predetermined portion of a skin material within a process of moving and vacuum-bonding the skin material to the surface of the base material with a vacuum bonding type. Further, in Document 2, the skin material is shaped by press molding with both male and female molds for thermoforming, and the vacuum suction from the female mold is performed without depending on the post-processing by cutting or the like of the tear line of this type of skin material. A method of thermoforming a tear line by sometimes projecting and retracting a blade attached to a male mold is disclosed.

Japanese Patent Laid-Open No. 10-34741 JP 2003-145617 A

  According to the method of Patent Document 1, the fabric material is not only partially distributed on the skin material, but is shaped by adhering to the substrate surface in a softened state even if the skin material is not previously molded. This is advantageous in terms of the cost of integral molding, but conversely, it is impossible to form a tear line on the back surface of the skin material. According to Document 2, a tear line can be formed at the time of molding. However, the shape of the tear line does not affect the inflation performance of the airbag body in consideration of the strength of the skin material as in the case where post-processing is required. As described above, it is necessary to repeat the trial production for finely setting the thin skin material, which requires a corresponding equipment cost.

  In any case, when an airbag is partially formed integrally on a so-called soft type instrument panel in which a skin material having a foam layer bonded to the skin is bonded to the base material, a tear line is formed on the back surface of the skin. As a premise, a molding facility for that purpose is required, and there remains a problem in terms of cost.

  In view of such a point, the present invention is directed to a skin region corresponding to a tear line of a door base material portion of an instrument panel manufactured by adhering a skin material having a foam layer adhered to the skin to the base material. It is an object of the present invention to provide an automobile airbag door that can eliminate the formation of a tear line and a method of manufacturing the same.

  In order to achieve this object, according to the present invention, according to claim 1, an airbag door is integrally formed on an instrument panel that is laminated by adhering a skin material having a foam layer adhered to the skin to a base material. At the same time, a flange portion surrounding the retainer door portion of the retainer that holds the airbag main body is joined to the door base portion of the base member, so that the retainer door portion is opened when the airbag is operated, and the door base portion. In an automobile airbag door that breaks and unfolds along the tear line, the tear line has a central tier that extends in a horizontal direction parallel to the front and rear sides at the middle position between the rectangular tear line and the front and rear sides. Symmetrical sides that extend gradually from the front and rear ends of the left and right sides of the line and the rectangular tear line toward the left and right ends of the center tear line The retainer door part is formed with a rectangular integral hinge part facing the square tear line, and slits along the central and side tear lines, and on the left and right sides. The integral hinge portion is characterized in that it is formed with a relatively lower strength than the integral hinge portions on the front and rear sides so as to break the epidermis along the center tear line and the side tear line.

  When a relatively large explosive force is applied to the central region of the retainer door during the operation of the airbag door, a relatively large driving force is applied to the front and rear retainer doors relative to the left and right retainer doors. At that time, the integral hinges on the left and right sides of the square retainer door are relatively low in strength, so that the left and right door base parts can be driven in the direction of deployment with the same driving force as the front and rear door base parts. Driven. Therefore, the side tear line part also breaks and unfolds following the center tear line part, and the tensile force of the same level is generated in the contacting skin line through the foam layer, and the corresponding parts on the four sides of the skin are slightly Stretch and break.

  At this time, in order to form the integral hinge portions on the left and right sides with relatively low strength, for example, according to claim 2, the integral hinge portions on the left and right sides are relatively positioned relative to the integral hinge portions on the front and rear sides. Thinly formed. As the shape of the side tear line, for example, according to claim 3, the side tear line is formed at the left and right ends of the central tear line at an intermediate position between the isosceles triangle shape, the curved shape along the isosceles triangle shape, and the upper base. Each is one of the trapezoids to be connected. In order to set the door base material portion on which the tear line is formed to a predetermined strength, according to the fourth aspect, the tear line is formed of a low strength portion in which the tear line is intermittently arranged.

  As a manufacturing method for improving the surface quality of the skin of such an instrument panel with an airbag door in a low-cost molding process, a thermoplastic skin material having a foam layer bonded to the skin is flattened according to claim 5. A vacuum suction mold for a base material on one of both sides in the vertical direction with respect to the skin material, and a vacuum suction mold for a skin material having a mold surface corresponding to a predetermined surface shape of the skin on the other side. The base material is provided in a facing state, a tear line is formed in the door base material portion, and the base material in which the intake passages are dispersedly formed is set in a vacuum suction type, and the skin material is softened by a heating process. The vacuum suction mold for the skin and the vacuum suction mold for the skin material are clamped and simultaneously vacuum suctioned by these vacuum suction molds allows the foamed layer to adhere to the substrate and the foamed layer to be compressed or expanded to form the skin material. For skin material To excipients along idle suction type mold surface of the.

  According to the airbag door of the present invention, even if the tear line is abolished with respect to the skin of the instrument panel in which the foam layer is interposed, the side portion of the door base material portion breaks and expands in conjunction with the front and rear portions. Thus, the side skin region is also reliably broken together with the foam layer, and the four-way opening is smoothly performed without impairing the inflation performance of the airbag body. Costs required for repeated prototyping or installation to form tear lines on the skin can be reduced.

  According to the method for manufacturing an airbag door of the present invention, the soft and tearless skin material is formed at the time of integral molding with respect to the base material, so that the molding in the previous process is unnecessary, and the skin material is the skin material. Since it is shaped along the vacuum suction type mold surface, not only the surface quality is improved, but also the design restrictions are reduced, and the substrate surface can be formed in a non-similar shape.

  An automobile airbag door according to an embodiment of the present invention will be described with reference to FIGS. 1 to 5. As shown in FIG. 3, the instrument panel 9 has four sides similar to those described above with reference to FIG. An open-type airbag door 7 is integrally formed, and the same or equivalent parts as described above will be described with the same symbols. That is, as shown in FIG. 1, an instrument panel 9 in which a skin material 10 in which a foam layer 12 made of PP foam (polypropylene foam) is joined to a skin 11 made of TPO is bonded to a base material 4 and laminated, The so-called soft instrument panel has a retainer door portion 35 in a corresponding rectangular opening 39 in a door base portion 20 constituting the airbag door 7 having a rectangular shape that is long in the vehicle width direction or the left-right direction. And the retainer 30 holding the airbag door main body 7a (FIG. 5) such as an inflator is integrated by vibration welding at a flange portion 34 surrounding the periphery thereof.

  The base material 4 is made of PP having a thickness of 2.5 mm, for example, and is injection-molded so that intake passages (not shown) are formed in a dispersed manner. As shown in FIG. 3, the door base material portion 20 includes a rectangular tear line 21 a corresponding to the rectangular shape of the retainer door portion 35 and a rectangular tear line 21 a that passes through the center position by post-processing cutting. The center tier line 21b that extends to the middle by an equal distance parallel to the front and back sides and the front and rear ends of the left and right sides of the rectangular tier line 21a are gradually narrowed toward the left and right ends of the center tier line 21b. A four-side opening type tear line 21 is formed, which is formed by a side tear line 21c that is symmetrical and isosceles triangular. As shown in FIG. 1, this tear line is formed, for example, by arranging thin portions having a depth of 0.5 mm, a width of 1 mm, and a length of 10 mm in the tear line direction at an interval of 1 mm.

  Correspondingly, as shown in FIG. 3, the retainer door portion 35 includes an integral hinge portion 31 on the front and rear sides and a integral hinge portion 31a on the left and right sides that form a square facing the square tear line 21a, A slit 32 is formed to face the tear line 21b and the side tear line 21c. As shown in FIG. 2, the retainer door portion has a plate thickness of 3 mm, for example, and the integral hinge portion 31 on the front and rear sides has a plate thickness of about 2.5 mm, for example. As indicated by a two-dot chain line in the figure, 31a is formed as thin as about 2 mm and has a relatively low strength. Thereby, the left and right portions of the triangular shape also rotate in conjunction with each other without the front and rear portions of the trapezoidal shape of the retainer door 35 rotating by the expansion force applied relatively strongly to the region of the central tear line 21b. The side tear lines 21c on both sides are also ruptured and deployed without delay, and the left and right regions of the skin 11 that contact each other are driven so as to open in four directions simultaneously with the front and rear regions.

  As a vacuum forming machine for integrally forming the tear lineless skin material 10 to the base material 4, as shown in FIG. 4, the skin material 10 is pulled and supported in a flat shape and can be separated from each other during the integral molding. A vacuum suction die 5 for the base material 4 is provided on the lower side of the clamp tool 18, and an electric surface having a die surface facing the convex mold portion 5 a and corresponding to the surface shape of the instrument panel 9 is provided on the upper side. A vacuum suction die 16 provided with a porous concave die 16a by casting is provided. The male vacuum suction mold 5 for the base material and the female vacuum suction mold 16 for the skin material are moved up and down toward the clamp tool 18 by an attached lifting device (not shown), and both coupling tools 17 and 17a are moved. The mold is clamped by connecting the concave and convex portions. Heaters 19 for heating the skin material 10 from both sides are arranged on both sides of the clamp tool 18, and can be moved to a side escape position during mold clamping. The mold surface 16 b of the concave mold 16 a is mostly similar to the mold surface of the convex mold 5 a or the surface of the substrate 4, but is formed in a predetermined surface shape of the instrument panel 9. The mold surfaces of the convex mold 5a and the concave mold 16a form a cavity having a separation distance that allows vacuum suction from both sides to the base material 4 and the skin material 10 in a clamped state.

  When the skin material 10 is integrally formed with the base material 4, the skin material 10 (FIG. 4A) that has been stored in a roll shape with a heat-meltable adhesive 13 applied to the back surface is stored in a required size. The base material 4 is set on the convex mold 5a of the vacuum suction mold 5 having a mold surface shape along the back surface (FIG. 4B). Next, the skin material 10 is heated by the heater 19 to be softened. Subsequently, the heater 19 is released, the vacuum suction mold 5 and the vacuum suction mold 16 are moved up and down toward the clamp tool 18 and clamped, and the suction port 16d communicates with the intake path of the convex mold 5a and the intake path. Vacuum suction is performed substantially simultaneously from the intake passage (both not shown) of the base material 4 to be performed. As a result, the foamed layer 12 is adhered to the base material 4 by the hot melt type olefin adhesive 13 and the skin 11 is closely adsorbed by the mold surface 16b of the porous concave mold 16a over the entire area. The thermally softened foamed layer 12 is compressed or expanded while being shaped along the mold surface 16b to produce an all-olefin three-layer instrument panel 9 (FIG. 4C).

  The air bag door 7 is configured by joining the retainer 30 to the door base material portion 20 of the manufactured instrument panel 9 as described above. During the operation, as shown in FIG. 5, in the process of further inflating the airbag door body 7 a that has been inflated from the normal state, a relatively large explosive force is applied to the central region of the retainer door portion 35, A relatively large driving force is applied to the front and rear door portions 30a and 30b with respect to the door portions 30c and 30d. At that time, since the integral hinge portions 31a on the left and right sides are relatively low in strength, the left and right door base material portions 20c and 20d generate a driving force as much as the front and rear door base material portions 20a and 20b. . Accordingly, the side tear line 21c is also surely broken and developed following the central tear line 21b, and the opposing double Y-shaped skin line also generates the same tensile force through the foamed layer 12, and is slightly By extending and breaking, the door portions 30a to 30d rotate in conjunction with the four directions. Thereby, the door base material portions 20a to 20d are broken and separated and scattered, and the contact portion of the skin 11 is broken and developed in all directions. Therefore, the airbag door main body 7a is inflated smoothly at a predetermined high speed without being deformed due to the incomplete breakage of the skin 11 from the illustrated state, and has a predetermined inflated shape from the airbag door 7 that is opened in all directions. Bulge.

  As shown in FIG. 6A, the side tear line is formed in a trapezoidal shape connected to the left and right ends of the central tear line at the middle position of the upper base from both ends of the right and left sides of the rectangular tear line. As shown in Fig. 5, it is conceivable to connect the central tear line to the left and right ends of the center tear line and to form a curved line along an isosceles triangle such as an arc or ellipse that is symmetrical with respect to the extension line. By the way, if the double V-shape without the central tear line is used, there are problems with the safety at the time of scattering because each of the four pieces of the base material has an acute angle. Therefore, various modified examples on the assumption that the central tear line exists. Can be considered. The low strength portion of the tear line can also be formed by intermittent perforations. Furthermore, the integral hinge portions on the left and right sides of the retainer can be formed relatively intermittently thin or perforated with lower strength than the front and rear sides.

  In addition to simultaneous suction, a three-layer instrument panel is set by setting a base material on one mold, setting a skin on the other mold, and foaming urethane raw material between the molds in a clamped state. The present invention can be applied even in the case of integrally molding.

It is sectional drawing by the AA line of FIG. 3 of the instrument panel with an airbag door by embodiment of this invention. It is sectional drawing of the integral hinge of the retainer door of the airbag door. It is a perspective view of the airbag door. It is a schematic sectional drawing explaining the vacuum bonding process of the vacuum forming machine integrally formed in the base material of the skin material of the instrument panel with an airbag door. It is sectional drawing by the BB line of FIG. 3 at the time of the action | operation start of the airbag door. It is a figure which shows the modification of the tear line of the airbag door. It is a perspective view of the conventional airbag door provided with the tear line. FIG. 8 is a cross-sectional view of a central tear line region of the airbag door of FIG. 7.

Explanation of symbols

4 Substrate 5, 16 Vacuum Suction Type 7 Airbag Door 9 Instrument Panel 10 Skin Material 11 Skin 12 Foam Layer 13 Olefin Adhesive 20 Door Base Part 21 Tier Line 21a Rectangular Tier Line 21b Central Tier Line 21c Side Part Tier line 30 Retainer 31 Integral hinge part on the front and rear sides 31a Integral hinge part on the left and right sides 32 Slit 35 Retainer door part

Claims (5)

An airbag door is integrally formed on the instrument panel that is laminated by adhering a skin material with a foam layer to the skin, and the airbag body is held on the door base material portion of the base material. The flange part surrounding the retainer door part of the retainer to be joined is joined, so that the retainer door part is opened when the airbag is activated, and the door base material part is broken and deployed along the tear line. At the bag door,
The tear line includes a rectangular tear line, a central tear line extending in the left-right direction parallel to the front and rear sides at an intermediate position between the front and rear sides, and the central tear line from the front and rear ends of the left and right sides of the rectangular tear line. It is composed of side tier lines with left and right symmetrical shapes that gradually narrow toward the left and right ends of
The retainer door portion is formed with a rectangular integral hinge portion opposed to the rectangular tear line, and slits along the central tear line and the side tear line, and the integral hinges on the left and right sides are formed. An automobile is characterized in that the part is formed with a relatively lower strength than the integral hinge parts on the front and rear sides so that the skin is broken along the center tear line and the side tear line. Airbag door.   2. The airbag door for an automobile according to claim 1, wherein the integral hinge portions on the left and right sides are formed relatively thinner than the integral hinge portions on the front and rear sides.   The side tear line is any one of an isosceles triangle shape, a curved shape along the isosceles triangle shape, and a trapezoidal shape connected to the left and right ends of the central tear line at an intermediate position of the upper base. The automobile airbag door according to claim 1 or 2.   4. The automobile airbag door according to any one of claims 1 to 3, wherein the tear line is formed of a low-strength portion in which the tear lines are intermittently arranged. A method of manufacturing an automobile airbag door according to claim 1,
A thermoplastic skin material in which a foam layer is bonded to the skin is supported in a flat shape, and a vacuum suction mold for a base material is provided on one of both sides in the vertical direction with respect to this skin material, and the other surface is provided with a predetermined skin. A vacuum suction mold for skin material having a mold surface corresponding to the surface shape of
Set the base material on which the tear line is formed on the door base material part and the intake passages are dispersedly formed in the vacuum suction type,
In a state where the skin material is softened by heating treatment, the vacuum suction mold for the base material and the vacuum suction mold for the skin material are clamped,
By simultaneously vacuuming with these vacuum suction molds, the foam layer is adhered to the base material, and the foam layer is compressed or expanded to bring the skin material along the surface of the vacuum suction mold for the skin material. The manufacturing method of the airbag door of a motor vehicle characterized by shape | molding.

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