JP2010047215A - Air bag door and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visually good looking seamless type airbag door having a break-scheduled portion which cannot be recognized from the outside easily and inexpensively. <P>SOLUTION: A skin 5 comprises a skin layer 13 having high resin density, and a foam layer 15 which is integrally formed on the back side of the skin layer 13, and has a large number of voids therein. The foam layer 15 has the resin density which is comparatively lower than that of the skin layer 13, and is gradually higher toward the skin layer 13. In a base material 3, a plurality of cutting parts 17 extending along the break-scheduled portion 7 is intermittently formed passing therethrough in the thickness direction intermittently. A plurality of slits 19 extending along the break-scheduled portion 7 is intermittently formed in the foam layer 15 of the skin. One end of the slit 19 is communicated with the cutting part 17, and the other end of the slit 19 is positioned in the middle position of the thickness direction of the foam layer 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is constituted by a panel composed of a resin base material and a resin skin integrally formed on the surface of the base material, surrounded by a planned fracture portion, and the planned fracture portion is broken by the operation of the airbag device. The present invention relates to an airbag door that is opened and an improved manufacturing method thereof.

  In the airbag door disclosed in Patent Document 1, a resin base material is integrally formed on the back surface of the resin skin material, and the slits correspond to the planned breakage provided on the outer periphery of the airbag door. A cut is formed so as to reach the skin material from the back surface of the substrate.

On the other hand, in the airbag door disclosed in Patent Document 2, a foamed layer is integrally formed between the resin skin material and the resin base material, and the breakage portion provided on the outer periphery of the airbag door is formed. Correspondingly, each of a large number of pores is drilled by laser processing so that the remaining pores reach the skin material from the back surface side of the base material so that some of the pores reach the foam layer from the back surface of the base material. Yes.
JP 2006-273194 A Japanese Patent No. 3916951

  However, since the skin materials in Patent Documents 1 and 2 are both thin, if the slits or pores are too close to the surface of the skin material, slits or pores are formed on the surface of the skin material, and the airbag There is a risk of adversely affecting the appearance of the door. In order to solve such a problem, highly accurate equipment is required, and as a result, the manufacturing cost of the airbag door is increased.

  Moreover, in patent document 1, the base material is set to the back surface of a skin material by setting the skin material previously shape | molded in one shaping | molding die, and filling the cavity formed between the other shaping | molding die with molten resin. Since they are integrally formed, two steps of a skin material forming process and a base material forming process are required, and the number of manufacturing steps and the manufacturing cost increase.

  On the other hand, in Patent Document 2, a pre-formed skin material is set in one mold, and a pre-formed base material is set in the other mold, and is formed between the back surface of the skin material and the surface of the base material. Since the foamed layer is integrally formed between the back surface of the skin material and the surface of the base material by filling the cavities with molten resin, the skin material molding process, the base material molding process, and the foam layer Three steps including the molding step are required, which further increases the number of manufacturing steps and the manufacturing cost, and deteriorates the mass productivity.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a so-called seamless type airbag door with a good appearance that cannot be identified from the outside due to the expected fracture portion, easily and inexpensively. That is.

  In order to achieve the above-described object, the present invention has a two-layer structure in which the skin is integrally formed with the skin layer and the foam layer, and the resin density of the foam layer is gradually increased as the skin layer is approached. Features.

  Specifically, the present invention is constituted by a panel composed of a resin base material and a resin skin integrally formed on the surface of the base material, surrounded by a portion to be broken, and is described above by the operation of the airbag device. The following solutions were taken for airbag doors that opened when the planned breakage portion was broken.

  That is, according to the first aspect of the present invention, the skin has a skin layer having a high resin density, a large number of voids inside, the resin density is lower than that of the skin layer, and gradually approaches the skin layer. A plurality of notches extending along the planned fracture portion are intermittently formed in the thickness direction in the base material. In the foam layer of the skin, a plurality of slits extending along the planned fracture portion are intermittently formed so that one end communicates with the notch portion and the other end is located in the middle portion in the thickness direction of the foam layer. It is characterized by being.

  According to a second aspect of the present invention, in the airbag door of the first aspect, the foam layer of the skin is directly formed on the surface of the base material.

  A third aspect of the present invention is a method of manufacturing the airbag door according to the first or second aspect, wherein the surface molding die having a molding surface for molding the substrate and the surface side of the skin, and the base A back surface mold having a molding surface for molding the back side of the material, and a plurality of protrusions intermittently formed so as to correspond to the notches, and the back surface mold can protrude from the front surface of the protrusion A mold having a plurality of slit forming blades for forming the slits is prepared intermittently, and the slit forming blades are arranged so that their tips are substantially flush with the tip surfaces of the protrusions. After retreating and closing the mold so that the front end surface of the protrusion comes into contact with the molding surface of the surface molding mold, the second mold is inserted into a cavity formed between the surface molding mold and the back molding die. 1 Fill the molten resin with A plurality of notches extending intermittently in the thickness direction is molded, and then the surface molding die or the back molding die is opened in the mold opening direction while leaving the substrate on the back molding die. The second molten resin is filled in the cavity formed between the surface molding die, the tip end surface of the protruding portion, and the base material, and the second molten resin near the molding surface of the surface molding die starts to solidify. At that time, the cavity volume is further expanded by moving the front surface mold or the back surface mold in the mold opening direction, and then the slit forming blade is positioned so that the tip is positioned in the middle of the cavity opening direction. By projecting from the front end surface of the projecting portion, a plurality of slits extending along the planned fracture portion are intermittently formed in the foam layer of the skin, and then the mold is opened to remove the panel. To do And butterflies.

  According to the first aspect of the present invention, since the foam layer is formed on the skin, the thickness of the skin is increased, and the slit may be formed so as to reach the middle portion in the thickness direction of the foam layer. Since the distance between the surface of the skin and the slit can be made longer than that, an airbag door in which the slit is not formed on the surface of the skin can be easily obtained without using highly accurate equipment. Even if the distance between the surface of the skin and the slit is increased, the skin layer and the foam layer are integrally formed, and the resin density of the foam layer gradually increases as it approaches the skin layer. During the operation of the bag device, the effect of the breakage of the foam layer spreads to the skin layer, and the planned breakage portion is easily broken.

  According to the second aspect of the present invention, since the hard skin layer that prevents the insertion of the slit forming blade is not formed between the base material and the foam layer, the slit forming blade or the like can be easily inserted into the foam layer. Therefore, the slit can be easily formed.

  According to the invention of claim 3, the base material and the skin having the foam layer and the skin layer integrated with the base material can be obtained by moving the front surface molding die or the back surface molding die with a common molding die. Can be molded. Therefore, since it is not necessary to form the base material and the skin with separate molds, the number of manufacturing steps can be reduced. As a result, mass productivity is promoted, and the airbag door can be manufactured easily and inexpensively.

  In addition, the slit can be easily formed by projecting the slit forming blade from the front end surface of the protruding portion of the back surface mold while leaving the base material and the skin in the mold, that is, the slit can be formed in the mold. Further, mass productivity is promoted, and an inexpensive airbag door can be easily manufactured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a front part of a passenger seat of an instrument panel 1 which is an interior product for a vehicle as a panel. 2 is a cross-sectional view taken along line AA in FIG. The instrument panel 1 has a two-layer structure including a resin base material 3 and a resin skin 5 integrally formed on the surface of the base material 3.

  As shown in FIG. 3, the instrument panel 1 is formed with a plan break portion 7 (tear line) having a substantially rectangular shape in plan view, and the plan break portion 7 is actuated by an airbag device 9 described later at the time of a vehicle collision. An airbag door 11 that is opened by breaking is surrounded by the planned breaking portion 7.

  As shown in FIGS. 4 and 5, the skin 5 is formed integrally with a skin layer 13 having a high resin density and a back surface side of the skin layer 13, and has a large number of voids (not shown) inside. In the foam layer 15, the resin density is lower than that of the skin layer 13 and gradually increases as the skin layer 13 is approached. The skin layer 13 is not on the back side of the foam layer 15, and the foam layer 15 is formed directly on the surface of the substrate 3.

  As shown in FIGS. 3 and 4, a plurality of cutout portions 17 extending along the planned fracture portion 7 are intermittently formed in the base material 3 in the thickness direction, and the plurality of cutout portions are formed. Between 17, as shown in FIG. 5, a non-notch forming portion 3 a is formed as a planned fracture portion in the base material 3. When the load is applied to the front surface side of the airbag door 11, the non-notch forming portion 3a is easily broken when the airbag device 9 is operated while preventing the airbag door 11 from being dented and deformed. The thickness is set in the direction of the planned fracture portion 7 (the tear line direction), that is, in the x and y directions shown in FIG. And the notch width W orthogonal to the direction of the planned break portion 7 of the notch 17 is formed larger than the width of the slit 19 in the same direction.

  In the foam layer 15 of the skin 5, a plurality of slits 19 extending along the planned fracture portion 7 are formed intermittently. One end of the slit 19 communicates with the cutout portion 17 and the other end of the slit 19 is located in the middle portion in the thickness direction of the foam layer 15 so as to approach the skin layer 13. Thereby, in the skin 5, the thin part 5a of the other end side of the slit 19 and the non-slit forming part 5b between the plurality of slits 19 are formed, and the thin part 5a and the non-slit forming part 5b are broken in the skin. Scheduled part. Since the thickness of the non-slit forming portion 5b in the direction of the planned breaking portion 7 is equal to the thickness of the non-notched forming portion 3a, the non-slit forming portion 5b is easily broken when the airbag device 9 is operated. .

  On the back surface of the airbag door 11 and the base material 3 around the outer periphery of the airbag door 11, a resin airbag shooter 21 is fixed by vibration welding. The airbag shooter 21 includes a frame body 23 having a substantially rectangular tube shape having a shooting port 25. The frame body 23 is disposed opposite to a front side wall 23a extending in the vehicle width direction and a rear side of the front side wall 23a. The rear side wall 23b extending in the vehicle width direction and the left and right side walls extending in the vehicle front-rear direction so as to connect the left and right edges of the front side wall 23a and the rear side wall 23b (the right side wall 23c is shown in FIG. 2) It consists of. A hooking hole 26 is formed through the front side wall 23a and the rear side wall 23b, and a stepped receiving portion 27 is formed on the inner side of the end surface on the shooting port 25 side of the rear side wall 23b. An airbag device 9 is housed inside the frame body 23. The airbag device 9 includes an airbag case 29 that stores an airbag and an inflator (not shown). The airbag case 29 is connected and supported by an instrument panel reinforcement (not shown) via a bracket (not shown). A hook 31 is fixed to the airbag case 29, and the hook 31 is inserted into the hooking hole 26. When the airbag device 9 is operated, the periphery of the retaining hole 26 is caught by the hook 31 so that the frame body 23 does not jump out.

  The shooting port 25 of the frame body 23 is covered (closed) by a resin flap 33 for reinforcing the airbag door 11. The base end edge of the flap 33 is integrally connected to the upper end edge (opening edge portion of the shooting port 25) of the front side wall 23a via a hinge 35 that curves in a substantially U shape. On the surface of the flap 33, vibration welding protrusions 37 are integrally projected in the vertical and horizontal directions, and the flap 33 is vibration welded to the back surface of the base material 3 through the protrusions 37. Further, the leading edge of the flap 33 is supported from below so as to be able to withstand the load from the indoor side by the receiving portion 27, and both side edges 33 a and 33 a extending from both ends of the proximal end edge of the flap 33 to the leading edge and the shooting port 25. A gap S1 is formed between the opening edge 23d (see FIG. 1).

  A flange 39 is integrally formed on the upper end of the frame body 23 (the end on the shooting port 25 side) so as to project outward. On the surface of the flange 39, vibration welding projections 37 are integrally projected vertically and horizontally, and the flange 39 is vibration welded to the back surface of the base material 3 around the outer periphery of the airbag door 11 via the projections 37. Yes.

  In the instrument panel 1 configured as described above, when the airbag of the airbag device 9 is inflated by the operation of the inflator, the flap 33 and the airbag door 11 are pressed upward by the inflation pressure, so that the planned break portion 7 That is, the non-notch forming portion 3a of the base material 3, the thin portion 5a and the non-slit forming portion 5b of the skin 5 are broken, and the flap 33 is rotated about the hinge 35 as the airbag door 11. Deploys integrally with the flap 33 upward in the front direction of the vehicle body. At this time, one end of the slit 19 communicates with the notch portion 17 and the thickness of the non-notch forming portion 3a and the non-slit forming portion 5b in the direction of the planned breaking portion 7 (the tear line direction) is thin. The non-notch forming portion 3a and the non-slit forming portion 5b are easily broken and the airbag door 11 is smoothly deployed.

  Here, a method for manufacturing the airbag door 11 will be described. 6 to 9, a first molten resin R1 for forming the base material 3 and a second molten resin R2 for forming the skin 5 are prepared. The molding die 47 includes a surface molding die (movable mold) 41 having a molding surface 41a for molding the surface side of the base material 3 and the skin 5, and a back surface having a molding surface 43a for molding the back surface side of the base material 3. A molding die (fixed die) 43 is provided. A plurality of protrusions 43 b are intermittently formed on the back surface mold 43 in the direction of the planned break portion 7 so as to correspond to the cutout portions 17. The back surface mold 43 has a plurality of slit forming blades 45 for forming the slits 19 intermittently in the direction of the planned fracture portion 7 so that the slits 19 can protrude from the front end surface 43c of the protrusion 43b by operating means (not shown). Provided. The first molten resin R1 is, for example, polypropylene (PP), and the second molten resin R2 is, for example, a mixture of a foaming agent in a thermoplastic resin such as thermoplastic olefin (TPO) or polyphenylene sulfide (PPS). is there. Here, there is no restriction | limiting in particular as a foaming agent, What is necessary is just to generate | occur | produce gas with a heat | fever, and any of a chemical foaming agent and a physical foaming agent may be sufficient.

  First, as shown in FIG. 6, the slit forming blade 45 is retracted so that the tip thereof is substantially flush with the tip surface 43c of the protrusion 43b, and the tip surface 43c of the protrusion 43b is formed by the surface molding. After the mold 47 is closed so as to come into contact with the molding surface 41a of the mold 41, the first molten resin R1 is filled and solidified in the cavity 49 formed between the front mold 41 and the back mold 43. Then, the base material 3 is formed.

  Next, as shown in FIG. 7, the surface molding die 41 is moved in the mold opening direction (arrow Y direction) while leaving the base material 3 on the back surface molding die 43, and the surface molding die 41 and the protrusion The second molten resin R2 is filled into the cavity 51 formed between the tip 43c of the portion 43b and the base material 3. The separation distance is preferably set to approximately 1/2 or more of the thickness (wall thickness) of the skin 5 to be molded. Thereafter, the second molten resin R2 in the vicinity of the molding surface 41a of the surface molding die 41 begins to solidify early due to the influence of the cooling of the surface molding die 41. On the other hand, the second molten resin R2 in the vicinity of the surface of the base material 3 has a resin temperature higher than that in the vicinity of the molding surface 41a of the surface molding die 41 and starts to solidify because the cooling of the back surface molding die 43 is relaxed by the base material 3. The gel is in a highly viscous state. When the second molten resin R2 in the vicinity of the molding surface 41a of the surface molding die 41 starts to solidify, the surface molding is performed with the base material 3 left on the back molding die 43 as shown in FIG. By further separating the mold 41 from the back surface mold 43 in the mold opening direction (arrow Y direction), the volume of the cavity 51 is expanded. Then, due to the volume expansion of the cavity 51, the second molten resin R <b> 2 that has been compressed (expanded by the surface molding die 41, the distal end surface 43 c of the protruding portion 43 b and the base material 3) is While being pulled by the molding surface 41a, it expands and expands due to a gas generated by a chemical reaction in the second molten resin R2 or an inert gas. As a result, a skin layer 13 having a high resin density is formed on the surface, and a foam layer 15 having a large number of voids therein and having a resin density lower than that of the skin layer 13 is integrally formed on the back side of the skin layer 13. The molded skin 5 is integrally formed on the surface of the substrate 3. Further, due to the temperature difference between the molding surface 41 a of the surface molding die 41 and the surface of the base material 3, the foam layer 15 is formed so as to gradually increase as the resin density approaches the skin layer 13. Since the second molten resin R2 in the vicinity of the surface of the base material 3 is in a gel state having a high viscosity when the volume of the cavity 51 starts to be expanded, the skin layer is formed on the back surface side of the foamed layer 15, that is, on the base material 3 side. Is not formed.

  Thereafter, as shown in FIG. 9, the slit forming blade 45 protrudes from the distal end surface 43c of the protruding portion 43b by the operation of the operating means so that the distal end portion is located in the middle of the cavity 51 in the mold opening direction (arrow Y direction). Let As a result, the plurality of slits 19 extending along the planned fracture portion 7 have one end communicating with the cutout portion 17 and the other end approaching the skin layer 13 and positioned at the middle portion in the thickness direction of the foam layer 15. Thus, it is intermittently formed on the foam layer 15 of the skin 5. Here, the skin 5 is formed from the skin layer 13 and the foam layer 15 and has a large thickness, and the slit 19 is formed so as not to reach the skin layer 13. Thus, the distance between the surface of the skin 5 and the slit 19 can be increased. Therefore, the slit 19 can be easily formed without using a high-precision equipment so that the formation location does not appear on the surface of the skin. Moreover, since the hard skin layer which prevents insertion of the slit formation blade 45 between the base material 3 and the foam layer 15 is not formed, the slit formation blade 45 can be easily inserted in the foam layer 15.

  Thereafter, the mold 47 is opened and the instrument panel 1 is removed.

  In the airbag door 11 manufactured in this way, the skin 5 is integrally formed of the skin layer 13 and the foam layer 15, and the resin density of the foam layer 15 gradually increases as the skin layer 13 is approached. When the airbag device 9 is operated, the effect of the breakage of the foam layer 15 spreads to the skin layer 13 and the breakable portion 7 is easily broken.

  According to the present embodiment, the base 3 and the skin 5 having the foam layer 15 and the skin layer 13 integrated with the base 3 can be shared by simply moving the front surface mold 41 or the back surface mold 43. It can be molded with the mold 47. Accordingly, since it is not necessary to form the base material 3 and the skin 5 with separate molds, the number of manufacturing steps can be reduced. As a result, mass productivity is promoted, and the airbag door 11 is easily and inexpensively manufactured. Can do.

  Further, the slit 19 can be easily formed by projecting the slit forming blade 45 from the projecting portion 43b tip surface 43c of the back surface molding die 43 with the base material 3 and the skin 5 left in the molding die 47, that is, molding. Since the slit 19 can be formed in the mold 47, the mass productivity is promoted, and the inexpensive airbag door 11 can be easily manufactured.

  In addition, in the said embodiment, although the fracture | rupture scheduled part 7 (tear line) was formed in the planar view substantially rectangular shape, you may form in the shape which connected the left-right symmetry by making H shape or two Y-shapes sideways. .

  In the above embodiment, the front surface mold 41 is a movable mold and the back surface mold 43 is a fixed mold, and the front surface mold 41 is moved and separated from the back surface mold 43 in the steps shown in FIGS. However, the movable mold and the fixed mold may be reversed and the back surface mold 43 may be moved away from the front surface mold 41. In short, the front surface mold 41 or the back surface mold 43 may be moved so that the volume of the cavity 51 is increased.

  In the above embodiment, the slit forming blade 45 is protruded after the skin 5 is formed on the surface of the substrate 3. However, after filling the second molten resin R <b> 2, the surface molding die 41 is moved from the back molding die 43 to the arrow Y. You may make it protrude immediately after separating in the direction.

  Moreover, in the said embodiment, although the instrument panel 1 was shown as a panel, this invention is applicable to interior components, such as a steering wheel and a side trim of a seat side.

  Further, the flange 39 and the frame body 23 do not necessarily have to be formed integrally, and may be assembled separately.

  Further, the leading edge of the flap 33 may not be supported by the receiving portion 27 from below. That is, the tip of the flap 33 may be positioned in the shooting port 25 of the frame body 23.

Further, the flap 33 and the frame body 23 may be welded to the back surface of the base material 3 by a welding method such as high-frequency welding other than vibration welding, or may be attached to the back surface of the base material 3 by a method other than welding.

  Moreover, the notch width W orthogonal to the direction 7 of the notch 17 to be broken (x direction, y direction) can be arbitrarily set. In this case, the notch width W on the anti-hinge 35 side of the airbag door 11 needs to have a width that does not prevent the airbag door 11 from rotating.

  The present invention is constituted by a panel composed of a resin base material and a resin skin integrally formed on the surface of the base material, surrounded by a planned fracture portion, and the planned fracture portion is broken by the operation of the airbag device. It is useful as an airbag door that opens and a method for manufacturing the airbag door.

It is a perspective view which shows the passenger seat front part of the instrument panel which concerns on embodiment. It is sectional drawing in the AA of FIG. It is a top view of the airbag door in FIG. It is sectional drawing in the BB line of FIG. It is sectional drawing in CC line of FIG. FIG. 5 is a molding process diagram corresponding to FIG. 4 showing a state in which a base material is molded by filling and solidifying a first molten resin. FIG. 7 is a molding process diagram showing a state in which the surface mold of the mold in FIG. 6 is spaced apart from the back mold in the mold opening direction and filled with a second molten resin. FIG. 8 is a molding process diagram showing a state in which the second molten resin is foamed by further separating the surface molding die of the molding die in FIG. 7 from the back surface molding die in the mold opening direction. It is a shaping | molding process figure which shows the state which made the slit formation blade protrude from the protrusion part front end surface after the shaping | molding process of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Instrument panel 3 Resin base material 5 Skin 7 Planned fracture part 9 Airbag apparatus 11 Airbag door 13 Skin layer 15 Foam layer 17 Notch part 19 Slit 41 Surface molding die 41a Molding surface 43 Back surface molding die 43a Molding surface 43b Projection Part 43c Tip surface 45 Slit forming blade 47 Mold 49 Cavity 51 Cavity R1 First molten resin R2 Second molten resin

Claims (3)

Air that is composed of a resin base material and a resin skin integrally formed on the surface of the base material, surrounded by a planned break portion, and is opened by the operation of the airbag device. A bag door,
The skin has a skin layer with a high resin density and a large number of voids inside, and the resin density is lower than that of the skin layer and gradually increases toward the skin layer. It consists of a foam layer molded in one piece,
In the base material, a plurality of cutout portions extending along the planned fracture portion are intermittently formed in the thickness direction,
In the foam layer of the skin, a plurality of slits extending along the planned fracture portion are intermittently formed so that one end communicates with the notch portion and the other end is positioned in the middle portion in the thickness direction of the foam layer. An air bag door characterized by that. The airbag door according to claim 1,
The airbag door according to claim 1, wherein the foam layer of the skin is formed directly on the surface of the substrate. A method for manufacturing an airbag door according to claim 1 or 2,
A surface molding die having a molding surface for molding the base material and the surface side of the skin, and a molding surface for molding the back surface side of the base material, and intermittently so that a plurality of protrusions correspond to the notches And a molding die provided with a plurality of slit forming blades that are intermittently provided on the back molding die so as to project from the front end surface of the projecting portion, and for forming the slits. ,
After the slit forming blade is retracted so that the tip thereof is substantially flush with the tip of the protruding portion, and the mold is closed so that the tip of the protruding portion contacts the molding surface of the surface molding die By filling the first molten resin in the cavity formed between the front surface mold and the back surface mold, a plurality of notches extending along the planned fracture portion are intermittently penetrated in the thickness direction. Molding the formed substrate,
Next, the cavity formed between the surface molding die, the tip end surface of the protrusion, and the substrate by moving the surface molding die or the back surface molding die in the mold opening direction while leaving the substrate on the back molding die When the second molten resin is filled in and the second molten resin in the vicinity of the molding surface of the surface molding die starts to solidify, the cavity volume is moved by moving the surface molding die or the back molding die in the mold opening direction. Further expanded
Thereafter, the slit forming blade is protruded from the front end surface of the protruding portion so that the front end portion is positioned in the middle of the mold opening direction of the cavity, thereby forming a plurality of slits extending along the planned fracture portion in the foam layer of the skin A method for manufacturing an airbag door, comprising: intermittently forming the mold and then opening the mold to remove the panel.

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