JP2009119830A - Foam-molding mold and foam-molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam-molding mold preventing the formation of burrs and a conspicuous stepped part in a molded article, and a foam-molding method using the mold. <P>SOLUTION: The foam-molding mold 1 has an upper mold 2 and a lower mold 3, wherein the mating face of the upper mold 2 and lower mold 3 is provided with packing 5 extending along the cavity of the mold, and a spacer for regulating an approach distance between the upper mold and lower mold. In the clamped state of the upper mold 2 and lower mold 3, an edge part 5b of the packing 5 is projected by about 5 mm or less into the cavity 6 of the mold 1 or flush. <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 packing provided on a mating surface of an upper mold and a lower mold. 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 gaps. In order to prevent this, in practice, there is a slight gap in the mating surface between the upper mold 11 and the lower mold 12 in the mold clamping state, 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 foam molding mold according to claim 1 is a foam molding mold having an upper mold and a lower mold, and extends along a cavity of the mold on a mating surface of the upper mold and the lower mold. In the foam molding mold provided with the existing packing, the edge of the packing is narrowed between the upper mold and the lower mold in a state where the upper mold and the lower mold are clamped. , Which is flush with the cavity of the mold or protrudes into the cavity, and a spacer for regulating the approach distance between the upper mold and the lower mold is provided on the mating surface of the upper mold and the lower mold It is characterized by that.

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

Mold for foam molding according to claim 3, in claim 1 or 2, clamping to the thickness t ₀ of the previous packing, the thickness t ₁ to a ratio t _{1 /} t ₀ of the packing after clamping Is 5 to 95%.

  According to a fourth aspect of the present invention, there is provided a metal mold for foam molding according to any one of the first to third aspects, wherein the spacer is integrated with an upper mold or a lower mold.

  The foam molding mold according to claim 5 is the mold according to any one of claims 1 to 3, wherein the spacer is a separate member from both the upper mold and the lower mold, and the spacer is the upper mold or the lower mold. It is characterized by being attached.

  A foam molding die according to claim 6 is the packing mounting groove according to any one of claims 1 to 5, wherein the packing is provided with a leg portion, and is provided on a mating surface of the upper die or the lower die. The packing is attached to the upper mold or the lower mold by engaging the leg portion with the upper mold or the lower mold.

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

  An eighth aspect of the present invention is the foam molding method according to the seventh aspect, wherein the seat pad is foam-molded.

When foam molding is performed using the mold of the present invention, since the edge of the packing is flush with the cavity or protrudes into the cavity when the mold is clamped, the mating surface of the upper mold and the lower mold The resin does not enter the burrs and burrs do not occur. In the present invention, since the spacer for regulating the approach distance between the upper mold and the lower mold is provided on the mating surface of the upper mold and the lower mold, the crushing margin of the packing becomes constant, and the edge of the packing The portion can be flush with the cavity surface, and the protruding length of the edge portion into the cavity can be as designed.
In addition, it is preferable that this crushing allowance is about 5-95% of the thickness of packing.

  In the present invention, by setting the protruding length of the packing edge portion to the cavity to 5 mm or less, it is possible to prevent a conspicuous step along the mating surface from occurring in the molded product. That is, even if there is a slight discrepancy in the edge of the cavity side of the mating surface between the upper mold and the lower mold, the molded product has a concave line made of a packing mark along the mating surface. Therefore, a conspicuous stepped portion 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).

  The spacer may be integrated with the upper mold or the lower mold, or may be a separate body. When the spacer is separated from the upper die or the lower die, the collapse allowance of the packing can be changed by changing the spacer to one having a different thickness. In the case of a separate body, the dimensional accuracy of the spacer can be increased.

  The packing is preferably detachable from the upper mold or the lower mold so that the packing can be exchanged. For this purpose, it is preferable that a packing mounting groove is provided on the mating surface of the upper mold or the lower mold and a leg portion is provided on the packing, and the leg portion is engaged with the packing mounting groove.

  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. The figure is a longitudinal sectional view of the lower mold when the mold is opened in FIG. 1 (b). Fig. 3 is a perspective view from the rear side of the molded seat back pad, Fig. 4 is a sectional view taken along the line IV-IV of Fig. 3, and Fig. 5 is an enlarged sectional view of a part of the molded product with a skin material. FIG. FIG. 7 is a sectional view showing another example of the packing, and FIGS. 8A and 8B are sectional views showing another example of the packing mounting structure. FIG. 9 is a cross-sectional view showing an example of spacer mounting.

  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 and a spacer portion 3 c are provided on the mating surface of the upper mold 2 and the lower mold 3.

  As clearly shown in FIG. 1, in this embodiment, a packing mounting groove 3 b is extended along the cavity 6 on the mating surface 3 a of the lower mold 3 so as to surround 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 the clamped state, the front edge 5b of the packing 5 is preferably flush with the cavity surfaces of the upper mold 2 and the lower mold 3 or protrudes 5 mm or less, particularly 1 mm or less.

  In the state before mold clamping, the thickness of the strip-like portion of the packing 5 is preferably about 5 mm or less.

  Furthermore, in this embodiment, the spacer portion 3c is extended on the mating surface 3a of the lower mold 3 so as to surround the packing mounting groove 3b along the packing mounting groove 3b.

The ratio t ₁ / t ₀ between the packing thickness t ₀ before mold clamping and the packing thickness t ₁ after mold clamping is preferably 5 to 95%. Thus, 5% to 95% of the thickness _{t 0} of the thickness of the spacer portion 3c mold clamping before packing 5, in particular 10-50%, especially about 10 to 30% is preferred.

  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 and the cavity 6 is filled 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. 4, 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).

  In this embodiment, since a spacer for regulating the approach distance between the upper mold and the lower mold is provided on the mating surface 3a of the upper mold 2 and the lower mold 3, the allowance for crushing the packing 5 is constant. The front edge portion 5b of the packing can be flush with the cavity surface, and the protruding length of the front edge portion 5b into the cavity can be as designed.

  The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, in FIG. 1B, the spacer portion 3c is integral with the lower die 3, but may be integral with the upper die. Moreover, you may attach another body to an upper mold | type or a lower mold | type as a spacer. As a separate attachment method, for example, a method of attaching with screws as shown in FIG.

  When the spacer is separated from the upper die 2 or the lower die 3, the spacer can be changed to one having a different thickness. In the case of a separate body, the dimensional accuracy of the spacer can be increased.

  In addition, the shape of the packing 5 may be a cross-sectional shape such as a concave shape, a hollow shape, a U-shape, and an H shape shown in FIGS. 7 (a) to (d).

  Further, 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. 8 (a) and 8 (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.

(A) The figure is a vertical step view of the right half of the mold for forming the seat back pad according to the embodiment, and (b) is an enlarged view of a portion B in (a). It is a longitudinal cross-sectional view of the lower mold | type at the time of the mold opening of FIG.1 (b). It is a perspective view from the back direction of the shape | molded seat back pad. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. 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. It is sectional drawing which shows another example of packing. It is sectional drawing which shows another example of packing attachment structure. It is sectional drawing which shows the example of attachment of a spacer.

Explanation of symbols

1,10 Mold 2,11 Upper mold 3,12 Lower mold 3a Matching surface 3b Mounting groove 3c Spacer part 4 Core 5, 5A, 5B, 5C, 5D, 5E, 5F Packing 5a Leg part 5b Front edge part 6 Cavity 8 Seat back pad 20 Spacer

Claims (8)

A mold for foam molding having an upper mold and a lower mold,
In a mold for foam molding in which a packing extending along a cavity of the mold is provided on a mating surface of the upper mold and the lower mold,
In a state where the upper mold and the lower mold are clamped, the edge of the packing is narrowly pressed by the upper mold and the lower mold, so that the mold cavity is flush with the mold cavity or protrudes into the cavity. And
A mold for foam molding, wherein a spacer for regulating an approach distance between the upper mold and the lower mold is provided on a mating surface of the upper mold and the lower mold.   2. The mold for foam molding according to claim 1, wherein, in the mold-clamped state, a protruding length of the packing edge into the cavity is 5 mm or less. According to claim 1 or 2, with respect to the thickness t ₀ of the clamping before packing, the ratio t _{1 /} t ₀ of the thickness t ₁ of the packing after mold clamping is characterized by a 5% to 95% Mold for foam molding.   4. The foam mold according to claim 1, wherein the spacer is integrated with an upper mold or a lower mold.   The foam molding according to any one of claims 1 to 3, wherein the spacer is a separate member from both the upper die and the lower die, and the spacer is attached to the upper die or the lower die. Mold.   6. The packing according to claim 1, wherein a leg portion is provided on the packing, and the leg portion engages with a packing mounting groove provided on a mating surface of the upper die or the lower die. Is attached to the upper die or the lower die.   A foam molding method using the mold for foam molding according to any one of claims 1 to 6.   8. The foam molding method according to claim 7, wherein the seat pad is foam-molded.

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