JP2005081575A - Foam molding machine and manufacturing method of foamed molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foam molding machine capable of reducing the density and weight of a foamed molded product by preventing the occurrence of flash at the time of vacuum forming. <P>SOLUTION: In the foam molding machine equipped with a mold 10, which is equipped with a lower mold 14 and an upper mold 18 and forms a foam molding space 24 inside the mating surfaces 20 of both molds by closing both molds, and a vacuum means 12. A first seal material 26 comprising a rubbery elastomer is provided to the outer peripheries of the mating surfaces 20 to form an outer peripheral space 28 while a second seal material 36 comprising the rubbery elastomer is provided to the mating surfaces 20 to seal the gap between the foam molding space 24 and the outer peripheral space 28, and an exhaust flow channel 40 for allowing the foam molding space 24 and the outer peripheral space 28 to communicate with each other is provided to a part on the peripheries of the mating surfaces 20. The vacuum means 12 is connected to the outer peripheral space 28 and the air in the outer peripheral space 28 is sucked by the vacuum means 12 to suck the air in the foam molding space 24 through the exhaust flow channel 40. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a foam molding apparatus for foaming a foam raw material under reduced pressure and a method for producing a foam molded body, and more particularly to a molding apparatus suitable for manufacturing a seat pad for an automobile or the like.

  In general, a synthetic resin foam molded article such as a flexible polyurethane foam having high elasticity is used for a seat pad and a furniture cushion of a vehicle such as an automobile. Such seat pads are required to have low density and light weight in accordance with the recent demand for weight reduction and cost reduction of automobiles. In order to reduce the density and weight of foamed molded products, and to ensure moldability for complex shaped products, various vacuum forming methods for foaming and curing foaming materials under atmospheric pressure lower than atmospheric pressure are proposed. (For example, see Patent Documents 1 to 4 below).

  In the conventional foam molding apparatus, as a configuration for decompressing the foam molding space, Patent Documents 1 and 2 provide a space sealed by a sealing material on the outer periphery of the mating surface of the molding die, and decompression means in this space Is connected, and the gas in the space is sucked to suck the gas in the foam molding space from a slight gap in the mating surface of the mold.

However, in such a conventional decompression configuration, a thin burr is likely to occur in the foamed molded product due to a slight gap in the mating surface of the mold, and a deburring operation is necessary after molding. In addition, the thin burr may remain on the die side on the mating surface, and in this case, cleaning of the die becomes complicated.
JP 2000-326346 A JP 2003-1650 A Japanese Patent Laid-Open No. 2003-1642 Japanese Patent Laid-Open No. 2003-19718

  The present invention has been made in view of the above points, and a foam molding apparatus and a foam molded body capable of preventing the generation of burrs during reduced pressure molding and reducing the density and weight of the foam molded body. It aims at providing the manufacturing method of.

  The foam molding apparatus according to the present invention includes a first mold and a second mold, and a mold that forms a foam molding space inside the mating surface by closing both molds, and sucks the gas in the foam molding space. And a decompression means for decompressing the interior of the foam molding space, the first sealing material comprising a rubber-like elastic body is provided on the outer periphery of the mating surface of the first mold and the second mold, and the first A closed outer peripheral space surrounding the mating surface is formed between the sealing material and the mating surface, and a second sealing material made of a rubber-like elastic body is provided on the mating surface, so that the foam molding space and the outer peripheral space are provided. And providing an exhaust passage for communicating the foam molding space and the outer peripheral space in a part of the periphery of the mating surface, and connecting the pressure reducing means to the outer peripheral space, Gas in the outer peripheral space by means Through the exhaust passage by sucking by sucking the gas in the foam molding space is obtained so as to vacuum.

  Further, in the method for producing a foam molded body of the present invention, the foam molding apparatus is used to supply a foam raw material into the foam molding space, operate the decompression means to decompress the foam molding space, and The raw material is foamed and molded.

  In the present invention, when the decompression means is operated, the gas in the outer peripheral space surrounding the outer periphery of the mating surface is sucked, and thereby the outer peripheral space is decompressed. At this time, since the mating surface is sealed by the second sealing material, the gas in the foam molding space is not exhausted from the entire circumference of the mating surface, but is exhausted at a part of the circumference of the mating surface. The air is exhausted from the flow path to the outer peripheral space, whereby the pressure in the foam molding space is reduced.

  Thus, according to the present invention, since the second sealing material is provided on the mating surface between the outer peripheral space to which the decompression means is connected and the foam molding space on the inside thereof, the space between the two is sealed. This eliminates the leakage of gas (suction exhaust), and therefore eliminates the entry of the foaming raw material into the mating surfaces, thereby preventing the generation of burrs. In this way, it is possible to produce a foamed molded product that is reduced in weight and weight while suppressing the generation of burrs.

  In the present invention, the mating surface of the first mold and the second mold is an electric discharge machining surface, and a groove is provided in the mating surface of the first mold, and the second seal material is a part of the groove. It is preferable that the second sealing material is pressed against the mating surface of the second mold to seal between the mating surfaces when the mold is closed. By providing the second sealing material on the electric discharge machining surface in this way, it is possible to improve the alignment accuracy of the die matching surface and ensure high sealing performance.

  According to the present invention, the second sealing material is provided on the mating surface between the outer peripheral space to which the decompression means is connected and the foam molding space on the inside thereof, and the gap between the two is sealed, thereby generating burrs on the mating surface. It is possible to prevent the foamed molded body having a low density and reduced in weight, and can be manufactured without any trouble.

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

  1 is a cross-sectional view of a foam molding apparatus according to an embodiment, FIG. 2 is an enlarged cross-sectional view of a portion A of the previous figure, FIG. 3 is a perspective view of the molding die 10 in the open state, and FIG. It is sectional drawing at the time of injection | pouring of the foaming raw material M. FIG.

  The foam molding apparatus of the embodiment is for molding an automobile seat pad P made of a flexible polyurethane foam, and includes a molding die 10 for molding the seat pad P and a decompression means 12 for decompressing the inside of the molding die 10. Prepare.

  The molding die 10 can open and close the lower die 14 by pivoting about a concave lower die 14 that opens upward substantially horizontally and a hinge portion 16 that is arranged at one end of the lower die 14. The upper mold 18 is an aluminum mold in this embodiment. Then, by closing the lower mold 14 and the upper mold 18, a foam molding space 24 corresponding to the pad shape is formed inside the mating surface (parting line) 20, which is a joint portion between the two molds. It has become.

  The mating surface 20a of the lower mold 14 is provided with a substantially constant width along the entire periphery of the opening periphery of the recess of the lower mold 12. Further, the mating surface 20b of the upper mold 18 is provided with a substantially constant width along the peripheral edge of the bottom surface of the upper mold 18 so as to correspond to the mating surface 20a of the lower mold 12. The both mating surfaces 20a and 20b are subjected to electric discharge machining, that is, the both mating surfaces 20a and 20b are electric discharge machining surfaces. As the electric discharge machining, a known method can be adopted. For example, after the lower mold 14 and the upper mold 18 are combined, electricity is applied to both molds and the aluminum on the mating surfaces 20a and 20b is melted. The mating surfaces 20a and 20b can be formed so as to contact each other without a gap.

  A first sealing material 26 made of a rubber-like elastic body is provided on the outer periphery of the mating surface 20 of the lower mold 14 and the upper mold 18, and the first sealing material 26 and the mating surface 20 A sealed annular outer peripheral space 28 surrounding the mating surface 20 is formed therebetween.

  More specifically, the lower mold 14 and the upper mold 18 are respectively provided with flange portions 30 and 32 on the outer periphery of the mating surface 20, and one of the flange portions 30 is provided with a sealing groove 34. The first sealing material 26 is mounted and is configured to seal between the flange portions 30 and 32 by being sandwiched between the other flange portion 32 when the mold is closed. In this embodiment, the sealing groove 34 is provided in the flange portion 30 of the lower mold 14, and the first sealing material 26 is made of sponge rubber made of silicone rubber and has a substantially trapezoidal cross section. It is configured to be compressed in the height direction when closed.

  The mating surface 20 of the lower mold 14 and the upper mold 18 is provided with a second sealing material 36 made of a rubber-like elastic body over the entire circumference, and the second sealing material 36 and the foam molding space 24 and the outer peripheral space. 28 is sealed.

  More specifically, a sealing groove 38 is provided on one mating surface 20b of the mating surfaces 20a and 20b of the lower mold 14 and the upper mold 18, and a part of the second sealing material 36 is provided in the groove 38. It is mounted so as to protrude from the mating surface 20b, and the second sealing material 36 is pressed against the other mating surface 20a when the mold is closed to seal between the mating surfaces 20a and 20b. In this embodiment, a sealing groove 38 extending in the longitudinal direction, that is, the circumferential direction is provided on the mating surface 20 b of the upper mold 18, and a string-like second sealing material 36 is fitted into the groove 38. Yes.

  As shown in an enlarged view in FIG. 2, the sealing groove 38 is provided at substantially the center in the width direction of the flat mating surface 20 b, and electric discharge machining surfaces are secured on both sides of the groove 38. The second sealing material 36 is not particularly limited as long as it can be pressed against the flat mating surface 20a of the lower mold 14 when the mold is closed to ensure the sealing performance between the mating surfaces 20a and 20b. In view of heat resistance and the like, a solid rubber seal material made of silicone rubber is used. Further, the cross-sectional shape of the second sealing material 36 is a circular shape in consideration of mounting properties and sealing properties. Further, the second sealing material 36 is set to a size such that, when fitted into the groove 38, a part of the second sealing material 36 protrudes from the mating surface 20b, which is an electric discharge machining surface.

  The protruding height is such that when the second sealing material 36 is compressed when the mold is closed, the sealing surfaces 20a and 20b of the lower mold 14 and the upper mold 18 can come into contact with each other while exhibiting the above-described sealing performance. It is preferable to set as follows. For example, when the diameter of the second sealing material 36 is 7 mm, the sealing groove 38 can be a groove having a square cross section with an opening width of 6 mm and a depth of 6 mm. Thus, it is preferable to set both the opening width and depth of the groove 38 to be smaller than the diameter of the second sealing material 36.

  The mating surface 20 of the lower mold 14 and the upper mold 18 is provided with an exhaust passage 40 that communicates the foam molding space 24 and the outer peripheral space 28 at a part of the circumference. In this embodiment, the exhaust flow path 40 is provided on the mating surface 20a of the lower mold 14 at one side (rear edge) of the substantially rectangular seat pad P, and extends in a substantially constant width. It is comprised by the four slit-shaped groove | channels which cross | intersect the surface 20a (refer FIG. 3). The exhaust flow path 40 formed in this way is a gas sufficient for exhaustion even when the second sealing material 36 of the upper mold 18 is pressed against the mating surface 20a of the lower mold 14 when the mold is closed. It is set to a depth that can secure the flow path.

  An exhaust hole 42 is provided in the outer peripheral space 28, and a vacuum pump 44 that is the decompression means 12 is connected to the exhaust hole 42 via a pipe 46. In this embodiment, the exhaust hole 42 is provided through the flange portion 30 of the lower mold 14 on one side of the seat pad P where the exhaust passage 40 is provided.

  The upper mold 18 includes an injection port 48 so that the foaming raw material M can be injected into the foam molding space 24 in a state where the lower mold 14 and the upper mold 18 are closed. The injection port 48 includes a driving device 50. The lid 52 is opened and closed. In the state where the lid 52 is opened, the foaming raw material M is injected from the injection port 48 into the foam molding space 24 by the injection device 54.

  When the seat pad is molded using the foam molding apparatus constructed as described above, first, as shown in FIG. And the vacuum pump 44 is operated to start exhausting from the outer peripheral space 28. Then, an injection device 54 is inserted into the injection port 48 to inject the foam raw material M into the foam molding space 24. After the injection, the lid 52 is closed as shown in FIG. The gas in the foam molding space 24 is sucked through the passage 40, and the pressure reduction starts. The foaming raw material M fills the space 24 while foaming in the foam molding space 24 thus decompressed. After the polyurethane foam is filled in the foam molding space 24, the vacuum pump 44 is stopped to finish the exhaust, and then the molding pad 10 is opened to remove the molded seat pad P.

  In the foam molding apparatus of the present embodiment described above, when the outer peripheral space 28 is depressurized by the depressurizing means 12, the mating surface 20 of the lower mold 14 and the upper mold 18 is sealed by the second sealing material 36. The gas in the foam molding space 24 is only discharged from the exhaust flow path 40 to the outer peripheral space 28, and leakage from other locations on the mating surface 20 is completely prevented. That is, the seal between the mating surfaces 20 of the lower mold 14 and the upper mold 18 is not only rubbed by the electric discharge machined surface, but also a seal by the second sealing material 36 is added, so that the gas from the mating surface 20 at the time of foam molding. Leakage outside is blocked. Therefore, it is possible to prevent the foaming raw material M that easily leaks along with the gas from entering the mating surface 20, and to prevent the generation of burrs.

  Further, in the present embodiment, the first sealing material 26 that seals the outer peripheral space 28 has a trapezoidal cross section. Therefore, the sealing material is less likely to move than when it has a circular cross section. Good sealing performance is ensured. Further, in the case of a trapezoidal cross section, durability is improved because it is less likely to sag in the height direction compared to a circular shape.

  In the above embodiment, the first sealing material 26 is provided on the flange portion 30 of the lower mold 14 and the second sealing material 36 is provided on the mating surface 20b of the upper mold 18. 26 may be provided on the upper die 18, the second seal material 36 may be provided on the lower die 14, or both the first seal material 26 and the second seal material 36 may be provided on the lower die 14 or the upper die 18. Good. Further, the present invention can be applied not only to a mold having a pair of upper and lower molds but also to a mold having a pair of left and right molds.

  The foam molding apparatus and the foam molded body manufacturing method of the present invention are suitable for manufacturing a seat pad that is a cushion body mainly used for automobile seats. However, the present invention is not limited to this, and cushions for various vehicles and households. It can be used for the production of various foamed molded products including the production of pads used for the body.

It is sectional drawing of the foam molding apparatus which concerns on one Embodiment of this invention. It is the A section enlarged view of FIG. It is a perspective view in the open state of the shaping | molding die of the foam molding apparatus. It is sectional drawing at the time of the foaming raw material injection | pouring of the foam molding apparatus.

Explanation of symbols

10 ... Mold 12 ... Pressure reducing means 14 ... Lower mold (second mold)
18 …… Upper mold (1st mold)
20 …… Molding surface of mold 20a …… Molding surface of lower mold 20b …… Molding surface of upper mold 24 …… Foaming molding space 26 …… First sealing material 28 …… Outer peripheral space 36 …… Second sealing material 38 …… Seal groove for second seal material 40 …… Exhaust flow path

Claims (3)

A mold that includes a first mold and a second mold and closes both molds to form a foam molding space inside the mating surface; and a gas in the foam molding space is sucked to decompress the foam molding space. In a foam molding apparatus comprising a decompression means,
A first sealing material made of a rubber-like elastic body is provided on the outer periphery of the mating surface of the first mold and the second mold, and is sealed between the first sealing material and the mating surface. Forming an outer peripheral space and providing a second sealing material made of a rubber-like elastic body on the mating surface to seal between the foam molding space and the outer peripheral space;
An exhaust passage that communicates the foam molding space and the outer peripheral space is provided at a part of the circumference of the mating surface, and the decompression unit is connected to the outer peripheral space, and the decompression unit A foam molding apparatus, wherein the gas in the foam molding space is sucked and decompressed through the exhaust passage by sucking gas.   The mating surface of the first mold and the second mold is an electric discharge machining surface, and a groove is provided in the mating surface of the first mold, and a part of the second sealing material projects from the mating surface in the groove. 2. The foam according to claim 1, wherein the foaming member is mounted in a state in which the second sealing material is pressed against the mating surface of the second mold when the mold is closed to seal between the mating surfaces. Molding equipment.   Using the foam molding apparatus according to claim 1 or 2, supplying a foam raw material into the foam molding space, operating the pressure reducing means to decompress the foam molding space, and foaming and molding the foam raw material. A method for producing a foam-molded article.

Images