JP2009006610A - Cover body for airbag device, method for manufacturing cover body for airbag device, and airbag device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a skin part hardly peelable and to reduce a manufacturing cost in regard to a cover body of an air bag in which a surface side of a base material is covered with the skin part. <P>SOLUTION: The skin part 42 is integrally formed at the surface side 41a of the base material 41. The skin part 42 is formed by reaction injection moulding (RIM molding) in which a resin material is injected into a metallic mold 50 equipped with the base material 41. A flange part 44 projecting to the surface side 41a is formed at a terminal 41b of the base material 41. The skin part 42 is formed so that thickness dimension may gradually increase from a fracture scheduled part 34 toward the flange part 44. When the air bag develops, force is dispersed to make the skin part 42 hardly peelable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cover body of an airbag device in which a surface side of a substrate is covered with a skin portion, a method for manufacturing the cover body of an airbag device, and an airbag device.

  Conventionally, for resin molded products that are interior parts such as automobile door trims, a preformed base material is mounted on a mold, a resin material is injected into the mold cavity, and a skin portion is formed on the surface side of the base material. An integrally formed configuration is known (for example, see Patent Document 1). Further, in this configuration, the terminal portion of the skin portion is folded back and integrated with the base material by the terminal processing mechanism incorporated in the mold. However, the configuration in which the terminal processing mechanism is incorporated in the mold has a problem that the structure of the mold becomes complicated and the manufacturing cost increases.

Further, as shown in FIG. 6 (a), in the configuration in which the skin portion 2 is formed on the front surface side of the base material 1 and the skin portion 2 is formed up to the back surface side so as to wind the terminal 1a of the base material 1, Although the skin portion 2 can be firmly adhered to the material 1, the manufacturing process is complicated, the manufacturing cost is increased, and the mass is increased. On the other hand, as shown in FIG. 6 (b), in the configuration in which the skin portion 2 is formed on the surface side of the base material 1 and the terminal 2a of the skin portion 2 is aligned with the terminal 1a of the base material 1, the skin portion 2 is It becomes easy to peel off from the base material 1. In particular, as shown in FIG. 6 (b), in the case where the movable member 4 is disposed close to the base member 1 or in the configuration in which the base material 1 constitutes the cover body of the airbag device and breaks at the tear line, the skin portion 2 There is a case in which a force in the direction of peeling the substrate 2 from the substrate 1 is applied, and the skin portion 2 has a problem that it is easily peeled off from the substrate 1.
Japanese Patent Laid-Open No. 10-296771 (page 5, FIG. 6 to FIG. 15)

  As in the conventional case, in the configuration in which the skin portion is formed on the surface side of the base material, and the skin portion is folded back, or the skin portion is formed up to the back surface side so as to wrap the terminal of the base material, the manufacturing process is complicated. As the manufacturing cost increases, the mass increases. In addition, in the configuration in which the terminal of the skin part is aligned with the terminal of the base material, there is a problem that the skin part easily peels off from the base material, so it is necessary to select a combination of raw materials and add an adhesion improving means. Cost increases.

  The present invention has been made in view of such points, and the cover body of the airbag device, the manufacturing method of the cover body of the airbag device capable of reducing the manufacturing cost while being able to firmly adhere the skin portion to the base material, and An object is to provide an airbag device.

  A cover body of an airbag device according to claim 1 is a cover body of an airbag device that covers a stored airbag and can be broken at a planned breakage portion when the airbag is inflated and deployed. A resinous skin part formed by introducing a resin material on the surface side of the base material and covering the surface side of the base material, the terminal of the base material protruding to the surface side and the terminal of the skin part The flange part which closely_contact | adheres was provided.

  And in this structure, the cover body which the external appearance improved is provided by covering the surface side of a base material with a skin part. Since the flange part which protrudes to the surface side was provided in the terminal of the base material, the area which a base material and an outer skin part contact | adhere increases, and an outer skin part adheres firmly to a base material. Since the mating part of the base material and the skin part faces the surface side, it becomes easy to treat the excess resin material at the terminal part of the skin part. Compared with a configuration in which the terminal of the skin is wound around the back side of the substrate, the amount of the resin material in the skin can be reduced, the weight is reduced, the manufacturing process is simplified, and the manufacturing cost is reduced.

  The cover body of the airbag device according to claim 2 is the cover body of the airbag device according to claim 1, wherein the thickness dimension of the skin portion gradually increases from the planned fracture portion toward the flange portion of the terminal of the base material. It is formed as follows.

  In this configuration, when the force applied to the cover body at the time of inflating and deploying the airbag is applied in a direction in which the skin portion is peeled off from the base material, the force is gradually dispersed in the portion where the thickness dimension gradually increases, While peeling is suppressed, force is concentrated on the planned fracture portion, and the planned fracture portion is effectively broken.

  The method for manufacturing a cover body for an airbag device according to claim 3 is a method for manufacturing a cover body for an airbag device that covers a stored airbag and can be broken at a planned breakage portion when the airbag is inflated and deployed. A base material provided with a flange portion projecting to the surface side at the terminal is attached to the mold, a cavity is formed on the surface side of the base material, and the mold is made with the corner portion of the flange portion as a mold-matching surface. It is closed, and a resin material is introduced into the cavity, and is closely adhered to the surface side and the flange portion of the base material to form a skin portion.

  And in this structure, the cover body which the external appearance improved is provided by covering the surface side of a base material with a skin part. Since the flange part which protrudes to the surface side was provided in the terminal of the base material, the area which a base material and an outer skin part contact | adhere increases, and an outer skin part adheres firmly to a base material. Since the mold-matching portion between the base material and the skin portion is located at the corner portion of the flange portion and faces the surface side, it is easy to process the excess resin material at the end portion of the skin portion. Compared with a configuration in which the terminal of the skin is wound around the back side of the substrate, the amount of the resin material in the skin can be reduced, the weight is reduced, the manufacturing process is simplified, and the manufacturing cost is reduced.

  The airbag device according to claim 4 is a bag-like airbag that is folded and stored, a case body that stores the airbag, a cover body that covers the airbag, and the airbag. And an inflator that inflates and deploys the gas supplied to the bag.

  And in this structure, since the cover body of Claim 1 or 2 was provided, the airbag apparatus with the favorable external appearance and reduced manufacturing cost is provided.

  According to this invention, the cover body which the external appearance improved can be provided by covering the surface side of a base material with a skin part. Since the flange part which protrudes to the surface side was provided in the terminal of the base material, the area which a base material and a skin part closely_contact | adhere increases, and a skin part can be firmly stuck to a base material. Since the mating part of the base material and the skin part faces the surface side, it is possible to easily treat the excess resin material at the terminal part of the skin part. Compared to a configuration in which the terminal of the skin is wound around the back side of the substrate, the amount of the resin material in the skin can be reduced, the weight can be reduced, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of a cover body for an airbag device, a method for manufacturing a cover body for an airbag device, and an airbag device according to the present invention will be described with reference to the drawings.

  In FIG. 2, reference numeral 10 denotes a passenger compartment of an automobile. A steering wheel 12 is provided in front of the driver's seat 11, and an airbag device 14 for a driver is provided on the steering wheel 12. In addition, an instrument panel 16 and a glove box lid 17 positioned below the instrument panel 16 are provided in front of the passenger seat (not shown). The airbag device 18 is provided. Note that the directions such as the up-down direction, the both-side direction, and the front-rear direction are described with reference to the straight direction of the automobile.

  As shown in FIGS. 2 and 3, the steering wheel 12 includes a boss portion 12a located at the center and connected to the steering shaft, an annular rim portion 12b surrounding the boss portion 12a, and the boss portions. In the present embodiment, there are provided three spoke portions 12c that connect the 12a and the rim portion 12b.

  An airbag device 14 is attached to the boss portion 12a of the steering wheel 12 so as to face the occupant of the driver's seat 11. The airbag device 14 is also called an airbag module. As shown in FIGS. 2 to 4, the case body 21, an airbag 22 attached to the case body 21, an inflator (not shown), and a cover body 24 are provided. Etc. The case body 21 has a box shape with the upper side opened, and a folded airbag 22 is accommodated inside the case body 21. The inflator is controlled by the control means to supply gas to the airbag 22, and is attached to the bottom of the case body 21 or stored on the bottom side of the case body 21.

  Further, the cover body 24 is a resin molded product called an airbag lid, etc., and as shown in FIGS. 1 to 4, a board portion 31 facing the passenger and a cylindrical shape from the back side of the board portion 31 And an inner side of the attachment piece 32 is a housing part 33 for the airbag 22. Then, facing the storage portion 33 of the airbag 22, the back surface side of the substrate portion 31 is recessed in a groove shape, and a planned fracture portion 34, which is a weaker portion weaker than other portions, is formed. The planned fracture portion 34 is also called a tear line, and in the present embodiment, four straight and asymmetrical planned door portions 35 are defined by the straight and curved planned fracture portions 34. Each door planned portion 35 is connected to the outer peripheral side portion of the mounting piece portion 32 and the mounting piece portion 32 which are non-deployed portions by hinge portions 36 which are portions where the planned breaking portion 34 is not formed. Yes.

  The substrate portion 31 and the mounting piece portion 32 are, for example, a base material 41 formed of a relatively hard resin and a surface portion 41a of the base material 41 at the portion of the substrate portion 31 integrally adhered. A two-layer airbag cover including a skin portion 42 formed of a softer resin than the covered base material 41 is configured. Further, at the end 41b on the outer periphery of the base material 41, a flange portion 44 protruding from the surface side is formed at least in a portion adjacent to the spoke portion 12c, so to speak, it has a substantially L-shaped cross section. Further, the front end portion of the flange portion 44 has a dimension L1 at which the inner surface side that is the planned fracture portion 34 side projects is larger than a dimension L2 at which the outer surface side that is the opposite side to the fracture planned portion 34 projects, and An acute corner 44a is formed on the tip side. Further, the skin portion 42 is in close contact with the surface of the substrate portion 31, and in the flange portion 44, the terminal 42b is in close contact with the entire inner surface of the flange portion 44, that is, the thickness dimension is L1. In other parts, for example, the part covering the planned door portion 35 and the planned fracture portion 34, the thickness dimension is L3 which is smaller than L1, and from the planned fracture portion 34 to the terminal 42b, that is, toward the end portion, the thickness gradually increases. The size is set to be large.

  The base material 41 is integrally formed by injection molding of, for example, polypropylene (PP) or PPC resin that is a resin obtained by adding an additive to polypropylene. The skin portion 42 is formed as non-foamed polyurethane by, for example, injection molding of TPO resin (thermoplastic olefin) which is an elastomeric resin, more preferably reaction injection molding (RIM molding) of two-component mixing. .

  As shown in FIG. 1, the manufacturing process of the cover body 24 is performed by mounting (inserting) a base material 41 previously injection-molded on a first mold (lower mold) 51 of a mold 50. The mold (upper mold) 52 is relatively moved to perform mold matching. In this state, a cavity 54 for forming the skin portion 42 is formed on the surface side 41 a of the substrate portion 31 of the base material 41. Further, in this state, the mold alignment surface (parting line) 55 between the first mold 51 and the second mold 52 is aligned with the corner 44 a of the flange 44 of the base material 41.

  Then, a two-component mixed resin material is injected into the cavity 54, and the skin portion 42 is integrally adhered to the surface side 41 a of the substrate portion 31 of the base material 41. At this time, the terminal 42b of the skin portion 42 is in close contact with the inner surface side of the flange portion 44.

  Next, with the skin portion 42 cooled and solidified, the mold 50 is opened, and the cover body 24 in which the base material 41 and the skin portion 42 are integrally formed is formed. When the resin material leaks from the mold fitting surface 55 of the mold 50 and a so-called burr is formed, the burr is cut off. This burr is orthogonal to the surface direction of the base material 41. Since it is formed so as to face in the direction and so to speak, it can be easily cut off.

  Next, a deployment operation of the airbag device 14 provided with the cover body 24 will be described.

  That is, as indicated by a broken line C in FIG. 4, when the automobile collides with the folded airbag 22 covered with the cover body 24, the control device operates the inflator and supplies gas to the airbag 22. Then, the airbag 22 is rapidly inflated and deployed, and the cover body 24 is broken along the planned breaking portion 34. Then, each door planned portion 35 rotates about the hinge portion 36 to form a protruding opening of the airbag 22, and the airbag 22 is deployed in front of the occupant.

  Here, when the airbag 22 is inflated and deployed and the cover body 24 is cleaved along the planned fracture portion 34, the skin portion 42 is cleaved together with the base material 41. The force that cuts the skin portion 42 has two points. As indicated by the chain line D, a component force in the direction of peeling the skin portion 42 from the base material 41 is generated. Here, since the skin portion 42 is formed so that the thickness dimension gradually increases from the planned fracture portion 34 to the terminal 42b, the force is distributed as shown by the arrow E, and the skin portion 42 is applied to the base material 41. Can hold firmly. Further, the portion of the skin portion 42 where the terminal 42 b has a large thickness is in close contact with the entire inner surface of the flange portion 44 of the base material 41, so that the skin portion 42 is firmly held by the base material 41.

  As described above, according to the present embodiment, the cover body 24 of the airbag device 14 that is an occupant protection device is integrally decorated by covering the surface side 41a of the base material 41 with the skin material 42 of reaction injection molding. Due to the two-layer cover structure, the appearance and feel can be easily improved.

  Further, when the airbag 22 is inflated and deployed and the cover body 24 is cleaved along the planned breaking portion 34, the skin portion 42 is peeled off from the base material 41. Since the thickness dimension is gradually increased from the planned fracture portion 34 to the terminal 42b, the force is dispersed, and the skin portion 42 is hard to be peeled off from the base material 41 and can be firmly held.

  The portion of the skin portion 42 where the thickness of the terminal 42b is large is in close contact with the entire inner surface of the flange portion 44 of the base material 41, ensuring a wide bonding area, and firmly fixing the skin portion 42 to the base material 41. Can be retained.

  Further, since the thickness dimension of the portion from the planned breakage portion 34 of the skin portion 42 to the terminal 42b is increased, the force applied during the inflation and deployment of the airbag 22 is concentrated on the portion of the planned breakage portion 34 to create the starting point of the break The cover body 24 can be easily broken along the planned breaking portion 34.

  In addition, the inner side surface of the flange portion 44 of the base material 41 functions as a sealing surface for the resin material that flows when the skin portion 42 is subjected to reaction injection molding. Therefore, even if the resin material leaks between the molds 51 and 52 to generate a so-called burr, this burr does not reach the back side of the base 41 and is orthogonal to the surface direction of the base 41 Since it is formed so as to rise in the direction of the surface and so to speak, it can be easily excised.

  In addition, the flange portion 44 of the base material 41 has a large dimension that the corner portion 44a protrudes and a small dimension that protrudes toward the terminal 41b. Can be improved.

  In particular, by providing the flange portion 44 of the base material 41 at a portion facing the other member such as the spoke portion 12c, the base material 41 is hardly exposed to the outside, and the appearance can be easily improved. And when it is provided in a portion facing the other member, even when the member is a movable member such as a door portion that opens and closes, the base material 41 protects the skin portion 42 and can maintain a good appearance over a long period of time. .

  In addition, the manufacturing process can be simplified and the manufacturing cost can be reduced, and the weight can be reduced by reducing the resin material, as compared with the configuration in which the skin portion 42 is formed so as to wrap around the back surface side of the base material 41.

  As described above, the configuration in which the skin portion 42 is in close contact with the flange portion 44 can function effectively when the appearance is improved at a position where a shearing force is applied.

  Next, as a second embodiment of the present invention, an airbag device 18 for a passenger on the passenger seat provided on the instrument panel 16 will be described.

  Although not shown, the airbag device 18 also includes a case body, an airbag attached to the case body, and an inflator. As shown in FIG. 5, the airbag device 18 is integrated with the instrument panel 16 or the instrument panel 16 as shown in FIG. As shown in FIGS. 1 to 4, a base material 41 having a flange portion 44 and a surface side 41 a of the base material 41 are provided. The skin part 42 which covers integrally is formed, and there exists an effect similar to 1st Embodiment. In the second embodiment, the dimension by which the flange portion 44 protrudes is equal to the thickness dimension of the skin portion 42, and the thickness dimension of the skin portion 42 is formed substantially constant in each portion. As in the first embodiment, the thickness of the skin portion 42 can be increased toward the flange portion 44.

  Further, in the second embodiment, a cover body 17 that is a door body of the glove box is provided in the vicinity of the cover body 61. With the opening and closing of the cover body 17 in the arrow F direction, The lid 17 that is a member may come into contact with the vicinity of the end of the base 41 of the cover 61. Here, in the present embodiment, since the flange portion 44 of the base material 41 is located in a portion facing the lid body 17, the skin portion 42 is prevented from being turned over, and the skin portion 42 is protected over the long term. Can be maintained well.

  In addition, the other member which the cover body 61 opposes is not restricted to the glove box cover body 17, and can be applied to various movable parts.

  Further, the cover body 61 can have an appropriate configuration such as vibration welding of an inner body made of TPO resin to the back surface of the base material 41.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a cover body of an airbag device in which the surface side of a base material is covered with a skin portion.

It is explanatory drawing of the manufacturing process of the II cross-section equivalent position of FIG. 2 which shows one Embodiment of the cover body of the airbag apparatus of this invention. It is a top view of a part of steering wheel provided with an airbag device same as the above. It is explanatory drawing which shows a part of motor vehicle provided with the airbag apparatus same as the above. It is explanatory drawing at the time of inflation deployment of the airbag of the airbag apparatus same as the above in the position equivalent to the II cross section of FIG. It is explanatory drawing which shows other embodiment of the cover body of the airbag apparatus of this invention, (a) is explanatory drawing of the II-II cross-section equivalent position of FIG. 3, (b) is a part of (a) It is an enlarged view. It is explanatory drawing which shows the structure of the conventional cover body, (a) is the structure which winds up a skin part in the back surface side, (b) is the structure which aligned the skin part with the terminal of the base material.

Explanation of symbols

14,18 Airbag device
21 Case body
22 airbag
24, 61 Cover body
34 Planned break
41 Substrate
41a Front side
41b terminal
42 Skin
44 Flange
50 molds
54 cavity
55 Mold mating surface

Claims (4)

A cover body of an airbag device that covers a stored airbag and can be broken at a planned breakage portion when the airbag is inflated and deployed,
A base material, and a resin skin formed by introducing a resin material on the surface side of the base material and covering the surface side of the base material;
A cover body of an air bag apparatus, wherein the end of the base material is provided with a flange portion that protrudes toward the surface side and closely contacts the end of the skin portion. The cover body for an airbag device according to claim 1, wherein the cover body is formed so that the thickness dimension of the skin portion gradually increases from the planned fracture portion toward the flange portion of the terminal of the base material. A method for manufacturing a cover body of an airbag device that covers a stored airbag and can be broken at a portion to be broken when the airbag is inflated and deployed,
Attach the base material provided with the flange part protruding to the surface side to the terminal to the mold,
Forming a cavity on the surface side of the base material, and closing the mold with the corners of the flange portion as a mold-matching surface;
A method for producing a cover body for an airbag device, wherein a resin material is introduced into the cavity, and a skin portion is formed in close contact with the surface side and the flange portion of the base material. A bag-shaped airbag folded and stored;
A case body for storing the airbag;
The cover body according to claim 1 or 2, which covers the airbag,
The airbag apparatus according to claim 1, further comprising an inflator that supplies gas to the airbag to inflate and deploy.

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