JP2009269190A - Method for manufacturing interior component for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce weight and cost, to shorten a molding cycle and to eliminate irregularity in an appearance, in a method for manufacturing an interior component for an automobile. <P>SOLUTION: A door trim main body 20 of a door trim 10 is constituted of a light-weighted cellular resin base material 21 having a shape holding property, a resin rib 22 integrated in a reverse face side, and a skin 23 bonded in a surface side of the cellular resin base material 21, a heat-softened cellular resin sheet S is formed into a required shape, by primary pressurization processing with mold clamping of molding upper and lower dies 41, 42, then secondary pressurization processing is carried out with pressure higher than that of primary pressurization, in the molding upper and lower dies 41, 42, a secondary pressurization time and an injection filling time are set at the same time, when injection-filling a molten resin M into grooves 424 of the lower dies 42 under a compressed state of the cellular resin base material 21, and the cellular resin base material 21 is integrated thereafter with the resin rib 22, by low-pressure press work capable of restoring a cushion layer 23b of the skin 23. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing automotive interior parts such as door trims, rear parcel shelves, floor trims, trunk trims, luggage trims, roof trims, and rear side trims, and in particular, can achieve weight reduction and shorten manufacturing time. It is related with the manufacturing method of the interior component for motor vehicles which can be manufactured at low cost by this, and also the external appearance design property was improved.

  Normally, automotive interior parts such as door trims, rear side trims, etc. are based on a heavy resin core with shape retention and mounting rigidity to the body panel. Generally, a structure with an excellent epidermis is attached. And since the heavy resin core material is used, the weight of the product is increased, so that there is a problem that the fuel efficiency and the mounting workability are deteriorated. Furthermore, as a molding method for molding this kind of interior parts, the mold is molded into the required shape by filling the molten resin into the mold, so the mold cost is high and the mass productivity is excellent even in terms of the molding cycle. I couldn't say that. In order to solve these drawbacks, recently, by using a foam resin material, it is possible to reduce the weight of the product, reduce the cost, and shorten the molding cycle. The forming method has been proposed.

  Next, a specific example using a foamed resin material will be described by taking a door trim mounted on the interior side of a vehicle door panel as an example. FIG. 13 is a front view of the door trim 1, and FIG. 14 is a sectional view of the door trim 1. The door trim 1 is molded into a required shape, is lightweight and has a shape retaining property, and a load is applied. It is affixed to the surface of the foamed resin base material 2 and the resin rib 3 integrated with the back surface of the foamed resin base material 2 such as a portion where deformation is likely to occur and a peripheral portion where warpage deformation is likely to occur. It is comprised from the skin 4 which improves an external appearance. Therefore, since the lightweight foamed resin base material 2 is used and the resin rib 3 is used only in places where rigidity is required, as shown in FIG. 15, less resin material is required, and structurally light weight is achieved. it can.

  As shown in FIG. 16, the molding die 5 includes a molding upper mold 6 that can move up and down by a predetermined stroke, and a fixed molding under the molding upper mold 6 as shown in FIG. It is comprised from the type | mold 7 and the injection machine 8 which supplies the material of the resin rib 3. As shown in FIG. More specifically, the molding upper die 6 is connected to the lifting cylinder 6a and is driven up and down by a predetermined stroke. The molding lower die 7 is provided with a manifold 7a and a gate 7b which are resin passages of molten resin from the injection machine 8. Is provided.

  Then, when the molded upper and lower molds 6 and 7 are in the mold open state, the foamed resin sheet 2A that is the material of the foamed resin base material 2 is heat-softened and then placed in the molded upper and lower molds 6 and 7, as shown in FIG. As shown, the molded upper and lower molds 6 and 7 are clamped, and the foamed resin sheet 2A is press-molded into a required shape to form the foamed resin substrate 2. Further, in order to integrate the resin rib 3 on the back surface of the foamed resin base material 2 simultaneously with the molding of the foamed resin base material 2 or with a slight time difference, the molten resin M is supplied from the injection machine 8 to the manifold 7a, The resin rib 3 can be integrated with the back surface of the foamed resin substrate 2 in a predetermined pattern shape by injection filling the groove 7c of the molded lower mold 7 through the gate 7b and cooling and solidifying the molten resin M. The skin 4 may be laminated on the foamed resin sheet 2A in advance, or may be integrally formed by overlapping at the time of molding. The structure and molding method of the door trim 1 based on the foamed resin base material 2 are shown in detail in Patent Document 1.

JP 2005-238518 A

  Thus, the door trim 1 provided with the foamed resin base material 2 and the resin rib 3 integrated on the back surface thereof can achieve weight reduction, can be manufactured at low cost, and has the advantage of excellent productivity. On the other hand, the following problems have been pointed out. That is, in the molding method of the door trim 1, a press chart of the molding upper die 6 is shown in FIG. 18, and the foamed resin base material 2 is press-molded in the primary pressurization step shown by (1) in FIG. In order to cool the foamed resin base material 2, the molding upper die 6 is raised, cooling air is blown from the molding lower die 7 side, and the cooling step shown by (2) in FIG. 18 is performed. Thereafter, the molding upper die 6 is lowered again, and the secondary pressurizing step shown by (3) in FIG. 18 is performed. Specifically, the secondary pressurization higher than the primary pressurization is performed for 15 to 20 seconds, and at the same time as the secondary pressurization is started, the molten resin M is injected and filled into the groove portion 7c of the molded lower mold 7. The At this time, even if the injection filling of the molten resin M is completed, the secondary pressurization is continued to ensure the adhesive strength between the foamed resin base material 2 and the resin rib 3. For example, when the mold upper mold 6 is raised and the mold is opened in a state where the foamed resin base material 2 and the resin rib 3 are not sufficiently bonded, as shown in FIG. In order to strengthen the adhesive strength between the foamed resin base material 2 and the resin rib 3, the secondary pressurization step shown in FIG. 18 (3) was performed for a long time. In this case, it has been pointed out that the pattern shape of the resin rib 3 is picked up on the surface of the product and the appearance design is remarkably deteriorated.

  The present invention has been made in view of such circumstances, and includes a foamed resin base material, a resin rib integrated on the back surface side thereof, and a skin laminated on the front surface side of the foamed resin base material. A method for manufacturing interior parts for automobiles, which can achieve weight reduction and can be manufactured at low cost, while producing good interior design, shortening the manufacturing time, and leading to cost reduction. It aims to provide a method.

  In order to solve the above problems, the present inventor, as a result of earnest research, has completed the injection filling of the molten resin in the secondary pressure state, and at the same time, the upper mold is raised so that only the cushion layer of the epidermis is restored. By adopting a restoration mode process that applies a strong crimping force between the foamed resin base material and the resin rib, it is possible to shorten the manufacturing time and find that no load is applied to the product appearance, and to complete the present invention. It came.

  That is, the present invention provides a foamed resin base material that is molded into a required shape and is lightweight and has shape retention, a resin rib having a predetermined pattern shape integrated with the back side of the foamed resin base material, and a foamed resin base material. A foamed resin sheet, which is a material of the foamed resin base material, in a method for producing an interior part for an automobile, which is integrated on the surface side of the material and is composed of a skin made of a laminated sheet material of a top layer and a cushion layer After heat-softening treatment, superimpose with the skin and set in the molding upper or lower mold, or heat-softening the foamed resin sheet laminated with the skin, then set in the molding upper and lower mold, then molding upper and lower mold Molding the foamed resin base material that molds the foamed resin base material with the skin applied along the cavity shape of the molded upper and lower molds by clamping them together and performing primary pressure treatment with the molded upper and lower molds Then, after the molding step of the foamed resin base material, secondary pressure treatment higher than the primary pressure is performed by the molded upper and lower molds, and the foamed resin base material is held between the molded upper and lower molds in a compressed state. The molten resin injection filling process in which the molten resin is injected and filled into the groove portion of the lower mold and the injection filling of the molten resin are completed, and at the same time, the upper mold is raised to restore the cushion layer of the skin. It is characterized by comprising a restoration mode step in which the resin rib is integrated with the foamed resin base material by a low pressure press with a molding upper and lower mold.

  Here, the interior parts for automobiles can be applied to door trims, rear parcel shelves, floor trims, trunk trims, luggage trims, roof trims, rear side trims, and the like. Furthermore, the foamed resin base material having the shape retaining property can be obtained after the foamed resin sheet is heat-softened and then molded into a desired curved shape in a molding die, so that there is no reinforcing material such as a rib. , Has rigidity (shape retention) enough to retain the shape even when removed from the mold. Also, if the product shape includes a high expansion ratio part, after the foamed resin sheet is heat-softened, a vacuum suction mechanism is provided in the molding die and the foamed resin sheet is vacuumed along the inner surface of the molding die. A suction force may be applied.

  As the foamed resin sheet, a material obtained by adding a foaming agent to a thermoplastic resin is used. The thermoplastic resin may be one type of thermoplastic resin or two or more types of thermoplastic resins. Preferably, polyethylene resin, polypropylene resin, polystyrene resin, polyethylene terephthalate resin, polyvinyl alcohol resin, vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin, acrylonitrile / butadiene / Styrene (ABS) resin or the like can be used. As the foaming agent, an organic foaming agent such as an azo compound, a sulfohydrazide compound, a nitroso compound or an azide compound, or an inorganic foaming agent such as sodium bicarbonate can be used. The foamed resin base material obtained by molding the foamed resin sheet into a required shape after heat softening treatment preferably has a foaming ratio of 2 to 10 times in consideration of the balance between the weight and strength of the product. The cell diameter of the foamed resin substrate at that time is preferably in the range of 0.1 μm to 2.0 mm, and the thickness is in the range of 0.5 to 30 mm, preferably 1 to 10 mm.

  And in order to improve an external appearance design property, the skin is integrated with the surface side of the foamed resin base material. The material of the skin is not limited, but is composed of a top layer that enhances the surface appearance and a laminated sheet material of a cushion layer that imparts cushioning performance. The top layer includes a thermoplastic olefin (TPO) sheet and a thermoplastic. Synthetic resin sheets such as urethane (TPU) sheets and PVC sheets, or fabric sheets such as woven fabrics, non-woven fabrics, and knitted fabrics can be used. Polypropylene foam, polyethylene foam, polyurethane foam, etc. are used as the cushion layer. can do.

  On the other hand, the thermoplastic resin used as the resin rib can be appropriately selected from a wide range of thermoplastic resins. Usually, those that can be preferably used include polyethylene resins, polypropylene resins, polystyrene resins, polyethylene terephthalate resins, polyvinyl alcohol resins, vinyl chloride resins, polyamide resins, polyacetal resins, polycarbonate resins, ionomer resins, Examples include acrylonitrile / butadiene / styrene (ABS) resin. Moreover, you may mix various fillers in these thermoplastic resins. Examples of the filler that can be used include inorganic fibers such as glass fiber and carbon fiber, and inorganic particles such as talc, clay, silica, and calcium carbonate. Moreover, various additives, such as antioxidant, a ultraviolet absorber, a coloring agent, a flame retardant, and a low shrinkage agent, may be mix | blended. Furthermore, the said resin rib is arrange | positioned along the predetermined pattern shape on the back surface of a foamed resin base material. The resin ribs are arranged at portions where loads are concentrated, such as a peripheral portion where warpage deformation or the like is likely to occur, and a waist portion or an armrest portion where load is easily applied.

  And the manufacturing method of the interior component for automobiles concerning the present invention includes a molding step of the foamed resin base material by the primary pressure treatment by the molding upper and lower molds, and a secondary process of higher pressure than the primary pressure. The molten resin is injected and filled on the back side of the foamed resin base material after the foamed resin substrate is compressed, and the upper mold is raised at the same time as the injection filling of the molten resin is completed. This mode is a mode in which the cushion layer is restored to the original state, and is constituted by a restoration mode step in which the resin rib is integrated on the back surface of the foamed resin base material with an appropriate pressing pressure of the molding upper and lower molds.

  Moreover, the mold is opened while the foamed resin base material is held on the mold surface of the molding upper mold between the molding process of the foamed resin base material by the primary pressure treatment of the molding upper and lower molds and the injection filling process of the molten resin, The cooling time of the foamed resin substrate may be shortened by blowing cooling air from the molded lower die to the space between the foamed resin substrate and the molded lower die.

  That is, the present invention is characterized in that the time of the secondary press treatment by the molding upper and lower molds and the injection filling time of the molten resin are set to be the same, and the subsequent low pressure processing step by the restoration mode is employed.

  Here, a molding die used in the method for manufacturing an interior part for an automobile is connected to a molding upper mold capable of moving up and down, a molding lower mold on a fixed side located below the molding upper mold, and a molding lower mold. The molten resin supplied from the injector is a resin rib that is drilled into the mold surface of the molded lower mold through resin passages such as a manifold and a gate provided in the molded lower mold. It is supplied into the groove portion corresponding to the pattern shape. In addition, a vacuum suction mechanism is attached to the molding upper mold to improve the shapeability of the skin laminated on the surface of the foamed resin base material during press molding of the foamed resin base material, and to narrow down the surface of the skin. A pattern or the like can be transferred. The vacuum suction mechanism attached to the molding upper mold raises the molding upper mold to cool the foamed resin base material and supplies cooling air between the back surface of the foamed resin base material and the molding lower mold. When forming the space to be used, it is used when holding the foamed resin base material on the upper mold. On the other hand, an air blow mechanism is attached to the molding lower mold, and this air blow mechanism can shorten the cooling cycle by blowing cooling air when molding the foamed resin base material.

  Further, in the method of the present invention, a mold clearance adjusting mechanism is provided in order to vary the mold clearance between the upper and lower molds in the primary pressurizing process and the secondary pressurizing process. For example, when the guide shim is inserted between the guide posts on the periphery of the molding die so as to be able to advance and retract, and the guide shim is inserted, the die clearance is large and the primary pressurizing state. Further, when the guide shim is retracted and the guide post is brought into direct contact, the mold clearance is very small, which is a state during secondary pressurization. It should be noted that the lowering stroke amount of the upper mold can be controlled by programming without using the guide shim.

  Therefore, according to the method of the present invention, since a lightweight foamed resin base material and a resin rib with a small projected area are used, only the resin rib is compared with a structure using a resin core material with a large projected area over the entire surface of the product. Since the injection pressure can be set lower than in the past, the load on the upper mold can be reduced, the amount of resin can be reduced, material costs can be saved, and the cooling time can be reduced compared to conventional resin cores. Therefore, the molding cycle can be greatly shortened.

  Furthermore, in the method of the present invention, after molding the foamed resin base material, when the molten resin is injected and filled in a secondary pressure state higher than the primary pressure, the time of the secondary pressure and the injection filling of the molten resin are performed. Set the same time to shorten the time, and as soon as the molten resin has been injected and filled, raise the molding die and restore only the cushion layer of the skin with the low pressure press. Since the restoration mode process of integrating the resin ribs on the surface is adopted, traces of the resin rib pattern shape do not appear on the product surface, and the appearance defect does not occur.

  As described above, the method of manufacturing an automotive interior part according to the present invention is a method of forming a molded resin base material having a higher pressure than the primary pressure after forming the foamed resin base material into a required shape by primary pressure treatment of the molded upper and lower molds. When the molten resin is injected and filled into the groove portion of the molded lower mold in a state where the foamed resin base material is compressed by the secondary pressure treatment, the secondary pressure time and the injection filling time of the molten resin are set to be the same, As soon as the injection filling of the molten resin is completed, the molding upper die is raised, and the foamed resin base material and the resin rib are integrated with a low-pressure press that restores the thickness of the cushion layer of the skin. The secondary pressurization time can be greatly shortened compared to conventional products, and when cooling the resin ribs, the press pressure by the molding upper and lower molds is low, so there is no need to pick up traces of ribs on the product surface. Good maintainability. Therefore, the cost can be reduced by shortening the time, and the appearance design can be maintained well.

  Hereinafter, a preferred embodiment of a method for manufacturing an automotive interior part according to the present invention will be described by illustrating a method for manufacturing a vehicle door trim. It should be noted that the gist of the present invention is as described in the claims, and the contents of the embodiments described below are merely examples of the present invention.

  FIG. 1 to FIG. 12 show an embodiment of the present invention, FIG. 1 is a front view showing an automobile door trim manufactured by the method of the present invention, and FIG. 2 is a longitudinal sectional view showing a configuration of the automobile door trim. FIG. 3 is an explanatory view showing the pattern shape of the resin rib in the automobile door trim, FIGS. 4 and 5 show molding dies used in the manufacturing method of the automotive door trim, and FIG. 4 shows the overall configuration of the molding dies. FIG. 5 is a structural explanatory view showing a vacuum suction mechanism and an air blow mechanism attached to the molding die, FIG. 6 is a press chart diagram of the molding die in the manufacturing method of the door trim for the automobile, and FIGS. 12 shows each process in the manufacturing method of the automobile door trim, FIG. 7 is a preheating process of the foamed resin sheet, FIG. 8 is a process of setting the foamed resin sheet, and FIG. Material formation Step 10 the process of cooling the foamed resin substrate 11 is injection filling process of the molten resin, FIG. 12 is an explanatory view showing each restoration mode process of the epidermis.

  1 and 2, an automotive door trim 10 is configured by attaching various functional parts to a door trim main body 20 formed into a desired curved surface shape. Specifically, an inside handle escutcheon 30 is attached to the inscribed portion of the door trim main body 20, and an armrest 31 swelled by an occupant who bulges indoors rests on the elbow in the middle of the door trim main body 20. A pull handle unit 32 and a power window switch escutcheon 33 are attached to the upper surface of the armrest 31, and a door pocket 34 that can accommodate equipment is provided below the armrest 31. A speaker grill 35 is attached to the door trim main body 20 or separately.

  As shown in FIG. 2, the door trim main body 20 is molded into a desired curved surface shape, and has a foamed resin base material 21 having a shape retaining property, and a resin rib integrated with the back surface side of the foamed resin base material 21. 22 and a skin 23 having a decorating function laminated on the surface side of the foamed resin base material 21. The foamed resin base material 21 is subjected to heat softening treatment of the foamed resin sheet so as to have shape retention, and then thermoformed into a required shape, for example, cold press molded with a molding die having a desired mold surface. About the expansion | deployment rate part, you may shape the foamed resin base material 21 using vacuum forming together.

  The foamed resin sheet has a structure in which a foaming agent is added to a general-purpose thermoplastic resin. The thermoplastic resin includes a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyethylene terephthalate resin, a polyvinyl alcohol resin, a chloride resin. Vinyl resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin, acrylonitrile / butadiene / styrene (ABS) resin, etc. can be used. As the foaming agent, organic foaming agents such as azodicarbonamide and bicarbonate An inorganic foaming agent such as sodium can be used. In this embodiment, a foamed resin sheet in which sodium bicarbonate is appropriately added as a foaming agent to a polypropylene resin is used. Moreover, the foaming magnification of the foamed resin base material 21 molded from this foamed resin sheet is set to 2 to 10 times, and the thickness is set to a range of 0.5 to 30 mm, particularly 1 to 10 mm.

  Next, the resin ribs 22 are disposed on the back surface side of the foamed resin base material 21 and, in particular, are set in a predetermined pattern extending in an intersecting manner as shown in FIG. In addition, as for this pattern, arbitrary pattern shapes may be selected if it is cross shape, such as a vertical and horizontal direction, an oblique direction, or a combination thereof. The resin rib 22 is made of a general-purpose synthetic resin molded body, and as a synthetic resin that can be preferably used normally, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyethylene terephthalate resin, a polyvinyl alcohol resin, a vinyl chloride resin, A polyamide resin, a polyacetal resin, a polycarbonate resin, an ionomer resin, an acrylonitrile / butadiene / styrene (ABS) resin, or the like may be selected as appropriate. Is used. The resin rib 22 is appropriately mixed with a filler such as inorganic fibers such as glass fiber and carbon fiber, and inorganic particles such as talc, clay, silica, and calcium carbonate in the thermoplastic resin. May be.

  As described above, the door trim main body 20 in the door trim 10 shown in FIGS. 1 to 3 includes a foamed resin base material 21 having shape retention, a resin rib 22 integrated on the back surface of the foamed resin base material 21, and a decoration. In addition to using the lightweight foamed resin base material 21, the resin core material occupied over the entire surface of the product as in the past can be abolished. The rib 22 has a bone-like shape, and a portion to which a load is applied, for example, a portion excluding the clip seat, the upper surface of the waist portion, the upper surface of the armrest portion, and the like has a thinning structure. In addition, the weight can be reduced by 40% or more, the resin material can be saved significantly, and the cost can be reduced.

  The skin 23 is made of a laminated sheet material having a back surface of a top layer 23a such as a thermoplastic olefin (TPO) sheet or a soft vinyl chloride (PVC) sheet and a cushion layer 23b made of polyethylene foam, polypropylene foam, polyurethane foam or the like. Has been.

  Next, the configuration of the molding die 40 used in the method for manufacturing the door trim 10 will be described. In practice, the door trim main body 20 is molded by the molding die 40, but as a manufacturing method of the door trim 10, it will be described below for convenience. The molding die 40 is roughly composed of a molding upper mold 41 capable of moving up and down by a predetermined stroke, a fixed molding lower mold 42 paired with the molding upper mold 41, and an injection machine 43 connected to the molding lower mold 42. It is configured.

  More specifically, the molding upper die 41 has a cavity portion 411 that matches the product shape, and is driven up and down by a predetermined stroke by an elevating cylinder 412 connected to the upper surface of the molding upper die 41. Guide posts 413 are provided at the four corners of the molding upper die 41.

  On the other hand, the molding lower die 42 is provided with a core portion 421 corresponding to the cavity portion 411 of the molding upper die 41. Further, in order to supply the molten resin M to the mold surface of the core portion 421, a manifold 422 and a gate 423 are provided, and the melt supplied from the injection machine 43 through the resin passages of the manifold 422 and the gate 423. Resin M is supplied to a groove portion 424 formed in the upper surface of the core portion 421. In addition, guide posts 425 that serve as a guide mechanism protrude from the four corners of the molding lower mold 42. The guide posts 425 guide the molding upper mold 41 when the molding upper and lower molds 41 and 42 are clamped. Since the guide shaft 414 of the post 413 is guided into the guide hole 425a of the guide post 425, the pressing posture of the upper mold 41 can be properly maintained. In the method of the present invention, a mold clearance adjustment mechanism 44 is attached to the guide posts 413 and 425 in order to vary the mold clearance of the molded upper and lower molds 41 and 42 between the primary pressure state and the secondary pressure state. . As an example of the mold clearance adjusting mechanism 44, a guide shim 441 is attached to a piston rod of a shim driving cylinder 442 so that it can be inserted between guide posts 413 and 425. By operation, the guide shim 441 is inserted or retracted between the guide posts 413 and 425.

  Therefore, when the guide upper and lower molds 41 and 42 are clamped by inserting the guide shim 441 between the guide posts 413 and 425, the mold clearance can be set large, which is the primary pressure state of the method of the present invention. Conversely, when the guide shim 441 is retracted from the guide posts 413 and 425 and the guide posts 413 and 425 are brought into direct contact with each other, the mold clearance can be set small and the secondary pressure state is established.

  Further, in the molding die 40 used in the method of the present invention, a vacuum suction mechanism 45 is attached to the molding upper die 41 as shown in FIG. That is, the vacuum suction pipe 452 connected to the vacuum suction pump 451 communicates with the air chamber 415 of the upper mold 41, and the opening / closing operation of the opening / closing valve 453 provided in the vacuum suction pipe 452 allows the inside of the air chamber 415 to be opened. Air can be evacuated, and vacuum holes 416 are formed in the mold surface of the molding upper mold 41 at predetermined pitch intervals. An air blow mechanism 46 is attached to the lower mold 42. That is, the air blow pipe 462 connected to the compressed air blower 461 communicates with the air chamber 426 of the molding lower mold 42, and air blow holes 427 having a hole diameter of about 10φ are formed at appropriate pitch intervals on the mold surface of the molding lower mold 42. Many have been established. Then, air can be blown from the air chamber 426 through the air blow hole 427 by opening / closing an opening / closing valve 463 provided in the air blow pipe 462.

  The molding die 40 is configured as described above, and a method for manufacturing the door trim 10 shown in FIGS. 1 to 3 using this molding die 40 will be described. Prior to that, a press chart of the molding upper die 41 will be briefly described with reference to FIG. First, after setting the material in the molding die 40, the molding upper die 41 descends from the upper limit position to the primary pressurization point (the in position of the guide shim 441) that is before the lower limit position, and at this primary pressurization point. The primary pressure treatment is performed for 10 seconds, and the foamed resin base material 21 is molded (area (1) in the chart of FIG. 6).

  After the molding of the foamed resin base material 21 by the primary pressure treatment, the molding upper die 41 is raised, and cooling air is supplied from the air blow mechanism 46 provided in the molding lower die 42 to the back side of the foamed resin base material 21. Sprayed and forced cooling is performed for about 10 seconds. At this time, the guide shim 441 is retracted out of the mold by driving the mold clearance adjusting mechanism 44 (area (2) in the chart of FIG. 6).

  Further, when the cooling process of the foamed resin base material 21 is completed, the molding upper die 41 is lowered again. At this time, the molding upper die 41 is lowered to a position where the guide posts 413 and 425 of the molding upper and lower molds 41 and 42 are in direct contact, that is, to a secondary pressurizing point (out position of the guide shim 441). A secondary pressurizing process in which a large pressurizing force (about 200 t) is applied for 9 seconds compared to the pressurizing force is performed, and at this secondary pressurizing, the molten resin M is injected and filled into the groove portion 424 of the lower molding die 42 (FIG. 6). (Area (3) in the chart). In addition, the injection filling time of the molten resin M at this time is the same as the secondary pressurizing time and is 9 seconds.

  Then, immediately after the injection filling process of the molten resin M, the molding upper die 41 rises, the cushion layer 23b of the skin 23 is restored to the original thickness, and the molding upper and lower dies 41, 42 are subjected to low pressure pressing. Then, a restoration mode process in which the resin ribs 22 are integrated with the back surface of the foamed resin base material 21 is performed (area (4) in the chart of FIG. 6). This restoration mode process is for 10 seconds.

  Hereafter, each process of this invention method is demonstrated in detail with reference to drawings. First, as shown in FIG. 7, the heater device 50 heats and softens a laminate of the skin 23 on one surface of the foamed resin sheet S at a predetermined temperature. In this embodiment, a polypropylene foam sheet (manufactured by Sumika Plustech, trade name: Sumiceller foam PP sheet, expansion ratio = 3 times, thickness 3 mm) is used as the foam resin sheet S.

  Next, as shown in FIG. 8, the heat-softened foamed resin sheet S (laminated with the skin 23) is set in the molds of the mold upper and lower molds 41 and 42 that are opened. Then, after the foamed resin sheet S is set, the lifting cylinder 412 of the molding upper die 41 operates to lower the molding upper die 41 by a predetermined stroke, so that the molding upper and lower dies 41 and 42 are molds as shown in FIG. A primary pressurizing process is performed in which the foamed resin sheet S is shaped along a desired mold surface shape. At this time, since the guide shim 441 is inserted between the guide posts 413 and 425 in the molding upper and lower molds 41 and 42 by driving the shim driving cylinder 442, the mold clearance is adjusted to 6 mm. The primary pressurization time is about 10 seconds.

  Next, after the primary pressure treatment is performed, the foamed resin base material 21 is cooled in the cooling step shown in FIG. At this time, the molding upper die 41 is raised, but the guide shim 441 by the die clearance adjusting mechanism 44 is in a shim-out state in which it is retracted out of the die by the contraction action of the shim driving cylinder 442, and the molding upper die 41 moves upward. Accordingly, the foamed resin base material 21 is held on the mold surface of the molding upper die 41 by driving the vacuum suction mechanism 45.

  The rising time of the molding upper die 41 is about 10 seconds, and at this time, the cooling air is bubbled from the air chamber 426 of the molding lower die 42 through the air blow holes 427 from the air blow mechanism 46 attached to the molding lower die 42. It is sprayed on the back surface of the resin base material 21, and this air blowing action can shorten the cooling time accompanying the molding of the foamed resin base material 21. Thereafter, as shown in FIG. 11, the molding upper die 41 is lowered again, and at this time, the guide shim 441 is retracted out of the die, and molding is performed until the guide posts 413 and 425 in the molding upper and lower dies 41 and 42 are in direct contact. The upper die 41 is lowered. At this time, the secondary pressure treatment is performed in a state in which the mold clearance is narrower than the clearance during the primary pressure, such as 3 to 5 mm.

  Furthermore, in this invention, this secondary pressurization time and the injection filling time of the molten resin M are set identically. In this embodiment, the cycle time can be significantly shortened by setting the time as short as 9 seconds. During this secondary pressurization, the molten resin M is injected and filled from the injection machine 43 into the groove 424 of the lower molding die 42 through the manifold 422 and the gate 423. As the molten resin M, use is made of Sumitomo Nobrene BUE81E6 (polypropylene manufactured by Sumitomo Chemical Co., Ltd., melt index = 80 g / 10 min) in which talc is appropriately mixed.

  Further, according to the method of the present invention, when the injection filling process of the molten resin M is completed, the upper mold 41 is raised to the extent that the cushion layer 23b of the skin 23 shown in FIG. A low pressure press according to 42 is performed. In this restoration mode step, only the thickness of the cushion layer 23b in the skin 23 is restored, and no excessive stress is applied, and no trace of the resin rib 22 is picked up on the product surface.

  As described above, according to the method of the present invention, the time of the secondary pressure treatment by the molding upper and lower molds 41 and 42 and the injection filling time of the molten resin M are set to be the same, and then the restoration mode process is adopted. Can significantly reduce the secondary pressurization time, thereby shortening the manufacturing time and avoiding excessive stress on the product surface, eliminating the adverse effects on the product surface and improving the appearance design. Can be increased.

  The embodiment described above relates to a method of manufacturing the door trim 10 for an automobile, but interior parts other than the door trim, such as interior parts such as a rear parcel shelf, a floor trim, a trunk trim, a luggage trim, a roof trim, a rear side trim, etc. The method of the present invention can be applied to all trims.

It is a front view which shows the door trim for motor vehicles manufactured by applying the method of this invention. It is the II-II sectional view taken on the line in FIG. It is a front view which shows the pattern shape of the resin rib after removing the foamed resin base material in the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the whole structure of the molding die used for the manufacturing method of the door trim for motor vehicles shown in FIG. FIG. 5 is a sectional view taken along line V-V in FIG. 4. It is a press chart figure of the shaping | molding upper mold | type in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the preheating process of the foamed resin sheet in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the setting process of the foamed resin sheet in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the formation process of the foamed resin base material in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the cooling process of the foamed resin base material in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the injection filling process of the molten resin in the manufacturing method of the door trim for motor vehicles shown in FIG. It is explanatory drawing which shows the restoration mode process of a skin in the manufacturing method of the door trim for motor vehicles shown in FIG. It is a front view which shows the conventional door trim for motor vehicles. FIG. 14 is a sectional view taken along line XIV-XIV in FIG. 13. It is explanatory drawing which shows the pattern shape of the resin rib in the conventional door trim for motor vehicles. It is sectional drawing which shows the structure of the shaping die used in order to shape | mold the conventional door trim for motor vehicles. It is explanatory drawing which shows the shaping | molding method of the conventional door trim for motor vehicles. It is a press chart figure of the shaping | molding upper mold | type in the shaping | molding method of the conventional automotive door trim. It is explanatory drawing which shows the malfunction point in the conventional door trim for motor vehicles.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automotive door trim 20 Door trim main body 21 Foamed resin base material 22 Resin rib 23 Skin 23a Top layer 23b Cushion layer 40 Molding die 41 Molding upper mold 413 Guide post 42 Molding lower mold 424 Groove part 425 Guide post 43 Injection machine 44 Mold clearance adjustment Mechanism 441 Guide shim 442 Shim driving cylinder 45 Vacuum suction mechanism 46 Air blow mechanism 50 Heater device S Foamed resin sheet M Molten resin

Claims (1)

A foamed resin base material (21) which is molded into a required shape and is lightweight and has shape retention; and a resin rib (22) having a predetermined pattern shape integrated on the back side of the foamed resin base material (21); An automotive interior part (20) integrated with the surface of the foamed resin substrate (21) and comprising a skin (23) made of a laminated sheet material of a top layer (23a) and a cushion layer (23b). )
The foamed resin sheet (S), which is the material of the foamed resin base material (21), is heat-softened and then overlapped with the skin (23) and set in the upper and lower molds (41, 42), or the skin The foamed resin sheet (S) laminated with (23) is heat-softened and then set in the molded upper and lower molds (41, 42), and then the molded upper and lower molds (41, 42) are clamped together and molded. Primary pressure treatment is performed by the upper and lower molds (41, 42), and the foamed resin base material (21) with the skin (23) is molded into the required shape along the cavity shape of the molded upper and lower molds (41, 42). Forming a foamed resin substrate (21);
After the molding step of the foamed resin base material (21), the secondary pressure treatment higher than the primary pressure is performed by the molding upper and lower molds (41, 42), and the foamed resin base material (21) is molded in the compressed state. An injection filling process of molten resin (M) that is held between the molds (41, 42) and injecting and filling the molten resin (M) from the injection machine (43) into the groove (424) of the molded lower mold (42); ,
At the same time as the injection filling of the molten resin (M) is completed, the molding upper die (41) is raised to lower the cushion layer (23b) of the outer skin (23) and the low pressure press by the molding upper and lower dies (41, 42). A restoration mode step of integrating the resin rib (22) with the foamed resin base material (21),
A method for producing an interior part for an automobile, comprising:

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