JP2009023211A - Metallic mold for foaming molding and method for foaming molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic mold for foaming molding which can prevent production of a burr and a remarkable level difference part in a molded article and to provide a method for foaming molding using the metallic mold. <P>SOLUTION: In the metallic mold 1 for foaming molding which has an upper mold 2 and a lower mold 3, a packing 5 extending along a cavity of the metallic mold is provided at a contacting surface between the upper mold 2 and the lower mold 3. In a state where the upper mold 2 and the lower mold 3 are clamped, an edge part 5b of the packing 5 projects to the cavity 6 of the metallic mold 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mold for manufacturing a resin foam molded article such as a seat pad, and more particularly to a mold having a packing provided on a mating surface between molds. The present invention also relates to a foam molding method using this mold.

  Foam molding such as flexible polyurethane foam for automobile seat pads is performed by foaming a urethane stock solution in a mold. FIG. 6A is a cross-sectional view showing an example of a conventional mold, and shows an enlarged vicinity of the mating surface. The mold 10 includes an upper mold 11 and a lower mold 12.

  In FIG. 6 (a), the upper mold 11 and the lower mold 12 are shown so as to come into close contact with each other without any gap. However, for the dimensional accuracy of the upper mold 11 and the lower mold 12 made of a casting or the like. Actually, there is a slight gap between the mating surfaces of the upper die 11 and the lower die 12, and burrs are generated.

As described in JP-A-9-99445, packing may be provided on the mating surface of the upper pad for foam molding of the seat pad with the lower mold.
JP-A-9-99445

I. In JP-A-9-99445, in order to install the packing on the mating surface, a groove extending slightly along the cavity is provided on the mating surface, and the packing is fitted and held in the groove. ing. This packing is arranged slightly apart from the cavity surface, and even when the mold is clamped, a gap exists on the mating surface on the cavity side with respect to the packing.

  When a seat pad is molded using such a mold disclosed in Japanese Patent Laid-Open No. 9-99445, urethane enters the gap on the cavity side of the packing on the mating surface, and burrs are generated.

  The burrs are removed by the worker after demolding, which is a cause of labor and cost for manufacturing a molded product such as a seat pad.

II. When foam molding is performed using the conventional mold 10 shown in FIG. 6, the edge of the mating surfaces 11a and 12a of the upper mold 11 and the lower mold 12 on the cavity side as shown in FIG. 6 (a) Some discrepancies may exist. That is, there may be a step that enters and exits the cavity 12.

  If such a stepped portion exists, a stepped portion 13a is generated in the molded product 13 as shown in FIG. 6 (b), and the appearance of the molded product may be lowered.

  When the molded product is a seat pad, as shown in FIG. 5 (b), the molded product (sheet pad) 13 is covered with the skin material 9, but when the skin material 9 is thin, the above-described step portion 13a is the skin material. The appearance of the seat pad may be reduced. Note that the dimension d in FIG. 5 (b) indicates the step of the step portion 13a.

  Further, the stepped portion 13a of the molded product 13 as described above has less bubbles and higher hardness than the surrounding portion of the molded product 13, and feels strange when touched with the finger or the like. May be impressed.

  In the conventional example of FIG. 6, as described above, burrs are generated in the molded product.

III. The present invention solves the above-mentioned problems I and II, and can prevent occurrence of burrs and conspicuous stepped portions in a molded product, and foam molding using this mold. It aims to provide a method.

  The mold for foam molding according to claim 1 is a mold for foam molding in which a packing extending along the cavity of the mold is provided on the mating surfaces of the molds. The edge of the projection protrudes into the cavity of the mold.

  According to a second aspect of the present invention, there is provided a mold for foam molding according to the first aspect, wherein a protruding length of the packing edge portion into the cavity in the clamped state is 5 mm or less.

  According to a third aspect of the present invention, there is provided a mold for foam molding according to the first or second aspect, wherein the mating surface is a mating surface of an upper mold and a lower mold.

  A foam molding method according to a fourth aspect uses the foam molding die according to any one of the first to third aspects.

  According to a fifth aspect of the present invention, the foam molding method according to the fourth aspect is characterized in that the seat pad is foam-molded.

  When foam molding is performed using the mold of the present invention, since the edge of the packing protrudes into the cavity in a state where the mold is clamped, the resin does not enter the mating surface and burrs do not occur.

  Also, even if there is a slight discrepancy in the edge of the mating surface on the cavity side, the molded product will have a recess made of a packing mark along the mating surface, and the conspicuous stepped portion is Does not occur. For this reason, the appearance of the molded product is improved and the touch when touched with fingers is also improved. This reason will be described in detail later with reference to FIG. 5 (a).

  By making the protruding length of the packing edge portion into the cavity 0.5 to 5 mm, the above effect can be sufficiently achieved.

  Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 (a) is a vertical step view of the right half of the seat back pad molding die according to the embodiment, FIG. 1 (b) is an enlarged view of portion B of FIG. 1 (a), and FIG. Fig. 3 is a perspective view from the rear side of the molded seat back pad, Fig. 3 is a sectional view taken along line III-III in Fig. 2, and Figs. 4 (a) and 4 (b) show other examples of the packing mounting structure. It is sectional drawing. FIG. 5 is an enlarged cross-sectional view of a part of a molded product with a skin material.

  A mold 1 according to this embodiment is for molding a seat back pad, and includes an upper mold 2, a lower mold 3, and a core 4 held by the upper mold 2. A packing 5 is provided on the mating surface of the upper mold 2 and the lower mold 3.

  As clearly shown in FIG. 2, in this embodiment, a packing mounting groove 3 b is extended on the mating surface 3 a of the lower mold 3 so as to surround the cavity 6 along the cavity 6. The packing 5 is attached to the lower mold 3 by fitting the leg portions 5a of the packing 5 into the packing attachment groove 3b.

  The packing 5 is in the form of a strip made of rubber or elastomer (preferably, an olefin-based elastomer, silicone rubber, fluorine rubber or the like having high elasticity). The packing 5 has a size such that the front edge 5b protrudes into the cavity 6 by a predetermined length in a mold-clamped state. The leg 5a is provided on the rear edge side of the packing 5 so as to protrude from the plate surface of the strip. The leg 5a and the packing mounting groove 3b have a shape in which the inlet side is narrow and the back side is wide, and the packing 5 is not easily detached from the lower mold 3.

  In a state where the mold is clamped, the front edge 5b of the packing 5 preferably protrudes from the cavity surface of the upper mold 2 and the lower mold 3 by 5 mm or less, particularly 0.5 to 5 mm, particularly about 1 to 3 mm.

  In the state before mold clamping, the thickness of the band plate-like portion of the packing 5 is preferably about 0.5 to 5 mm. In the state after mold clamping, the upper mold 2 and the lower mold 3 are clamped. It is preferable that the thickness of the band plate portion is about 40 to 80% of the original thickness.

  In order to perform molding using the mold 1 configured as described above, a mold release agent is applied to the inner surface of the mold 1 in the mold open state, and then a urethane stock solution is supplied into the cavity 6 of the lower mold 3 to clamp the mold. And heat to foam urethane. In addition, you may exhaust the gas at this time out of the metal mold | die 1 by operating the negative pressure source which is not shown in figure.

  When the urethane is sufficiently foamed to fill the cavity 4 with the foamed urethane and then the mold is opened after a predetermined time has elapsed, a seat back pad 8 made of a polyurethane foam foam molded product is obtained as shown in FIG.

  In the molded seat back pad 8, as shown in an enlarged view in FIG. 3, a recess 8 a made up of a drop mark of the front edge 5 b of the packing 5 extends. The concave strip 8 a extends along the position of the mating surface between the upper mold 2 and the lower mold 3.

  In this embodiment, since the urethane does not enter the mating surface between the upper mold 2 and the lower mold 3, no burrs are generated. Further, since the groove 8a extends along this mating surface position, even if the mating surfaces of the upper mold 2 and the lower mold 3 are shifted as shown in FIG. The pad 8 does not have a step that impairs the appearance after the skin material is mounted.

  The reason for this will be described with reference to FIG. FIG. 5 (a) shows a concave strip in which a skin material 9 is adhered to a seat back pad 8 formed by a mold in which an upper mold protrudes toward the cavity from a lower mold by a distance d (millimeter). It is sectional drawing of 8a vicinity.

  In the molded seat back pad 8, the portion 8 </ b> A formed in contact with the lower die is formed in contact with the upper die because the upper die protrudes by d from the lower die. That is, it protrudes by d from 8B. In this case, since the recess 8a extends along the boundary between the portions 8A and 8B on the surface of the seat back pad 8, the skin material 9 is gently continuous from the upper 8A portion to the lower 8B portion. Will come to do. That is, the level difference of the skin material 9 becomes gentle by the width of the concave stripe 8a, the level difference is not conspicuous, and the appearance is good. Moreover, even if it touches with a finger etc., it is hardly impressed. In this respect, even if the skin material 9 is applied, the stepped portion appears in a stepped manner, which is significantly different from the conventional example of FIG. 5 (b).

  The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, the shape of the leg portion 5a of the packing 5 and the lower mold packing mounting groove 3b into which it is fitted may be a cross-sectional shape such as a trapezoid or a circle shown in FIGS. 4 (a) and 4 (b).

  Although the seat back pad is formed in the above embodiment, the seat cushion pad can be formed in the same manner. The present invention can be applied to molding of a resin foam molded product other than a seat pad.

  The present invention can be applied not only to the mating surface of the upper mold and the lower mold but also to all the mating points of the molds such as the upper mold and the core and the lower mold and the core.

(A) The figure is a longitudinal cross-sectional view of the right half of the mold for forming a seat back pad according to the embodiment, and (b) is an enlarged view of a portion B in (a). It is a perspective view from the back direction of the shape | molded seat back pad. It is the III-III sectional view taken on the line of FIG. It is sectional drawing which shows another example of packing attachment structure. It is a partial expanded sectional view of the molded product which stuck the skin material. It is sectional drawing explaining the metal mold | die and molded product which concern on a prior art example.

Explanation of symbols

1,10 Mold 2,11 Upper mold 3,12 Lower mold 4 Core 5,5A, 5B Packing 5a Leg 5b Front edge 6 Cavity 8 Seat back pad

Claims (5)

In the mold for foam molding in which a packing extending along the mold cavity is provided on the mating surface between the molds,
A mold for foam molding, wherein an edge of the packing protrudes into a cavity of the mold when the mold is clamped.   2. The mold for foam molding according to claim 1, wherein a protruding length of the packing edge into the cavity in the clamped state is 5 mm or less.   3. The mold for foam molding according to claim 1, wherein the mating surface is a mating surface of an upper mold and a lower mold.   A foam molding method using the mold for foam molding according to any one of claims 1 to 3.   5. The foam molding method according to claim 4, wherein the seat pad is foam-molded.

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