JP2008093931A - Mold for molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding capable of eliminating damages of through-hole molding parts of both a fixed mold and a movable mold, and of preventing burrs from projecting to the outside of the surface of a molded article from the end part of the through-hole molded. <P>SOLUTION: The mold 10 for molding consists of the fixed mold 1 and the movable mold 2, and is for molding a floor spacer W with through-holes W1. In a cavity formed by the fixed mold 1 and the movable mold 2, first projected parts 12 and second projected parts 22 for molding the through-holes W1 are respectively provided at corresponding positions, and under a posture where the fixed mold 1 and the movable mold 2 are clamped, gaps G are formed between the first projected parts 12 and the second projected parts 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a molding die for forming a molded product having a through-hole with a fixed die and a movable die, and in particular, it is possible to eliminate damage to the through-hole molding portions of both the fixed die and the movable die. Furthermore, the present invention relates to a molding die that can prevent burrs from protruding from the end portion of the formed through-hole to the outer surface of the molded product.

  In order to ensure the flatness of the vehicle floor or to improve sound absorption performance, to protect passengers against impacts generated inside and outside the vehicle, and for the purpose of reducing the weight of the vehicle. In addition, a floor spacer made of a foamed resin molding is installed on the floor frame of the vehicle.

  There are various methods for forming the floor spacer. As a method for forming the floor spacer provided with a large number of through holes in order to provide the sound absorbing performance, for example, a technique disclosed in Patent Document 1 can be cited. This forming method will be described with reference to FIG. 7a. A sound absorbing hole forming portion a1 for forming a sound absorbing hole is formed in a cavity mold a having at least an ejector pin out of a pair of molds a and b. Furthermore, by setting the mold release resistance of the floor spacer w with respect to the cavity mold a to be larger than the mold release resistance of the core mold b not provided with the ejector pin, the mold can be easily released from the floor spacer w. is there.

JP 2003-340858 A

  According to the molding die and the molding method disclosed in Patent Document 1, it is easy to release the floor spacer molded in the mold. However, since the sound absorption hole forming part a1 and the core mold b are in contact (contact) when the mold is clamped, as shown in FIG. At the end of the hole w1 (parting line between the sound absorbing hole forming part a1 and the core mold b), a burr B protruding outside the floor spacer is likely to occur. This burr must come off and come into contact with other floor spacers, packing materials, and workers' hands when transporting the floor spacer, etc., and be removed after processing due to poor appearance. It is also a factor that deteriorates productivity. Therefore, even if a burr occurs, if it does not protrude outside the floor spacer, there is no contact with other products or hands, and the problem that the burr peels off or is removed by post-processing cannot occur.

  In addition, when the mold for molding the floor spacer having the through hole is configured so that the sound absorbing hole molding portion and the core mold abut when the mold is clamped as described above, the abutment of both molds There is also a problem that the part is likely to deteriorate due to repeated use, and the maintenance cost and replacement cost of the mold increase.

  The molding die of the present invention has been made in view of the above-described problems, and in a molded product such as a floor spacer having a through hole, without generating a burr protruding from the end of the through hole to the outside of the molded product. Furthermore, it is an object of the present invention to provide a molding die in which deterioration of the through-hole forming portions of the fixed die and the movable die constituting the molding die hardly occurs.

  In order to achieve the above object, a mold according to the present invention is a mold for forming a molded product having a through hole with a fixed mold and a movable mold, and is formed by the fixed mold and the movable mold. In the cavity, a first convex portion and a second convex portion for forming the through hole are provided at corresponding positions, respectively, and the first mold and the movable mold are clamped in the first clamped position. A gap is formed between the convex portion and the second convex portion.

  The molding die of the present invention is a molding product having a plurality of through-holes provided to give sound absorbing performance, more specifically, a molding die suitable for manufacturing a vehicle floor spacer, and its configuration is a fixed die And a movable type. The vehicle floor spacer includes a lower limb shock absorbing pad for protecting an occupant from an impact at the time of a vehicle collision, a horizontal pad for adjusting a passenger compartment space, and a product in which they are integrally molded. Is.

  Cavities in the shape of the molded product are defined in a posture in which the fixed mold and the movable mold are clamped, but the cavities formed by both molds are provided with convex portions for forming through holes, respectively. . For example, when four through-holes are formed in one molded product, four convex portions are provided at corresponding portions of both the fixed mold and the movable mold. The two corresponding protrusions may have the same cross-sectional dimension, or one of them may have a relatively large dimension. Furthermore, the cross-sectional shape may be a polygonal shape including a square and a rectangle in addition to a circle. If the through-hole is formed in a shape with a different cross-sectional dimension in the middle, the floor spacer is installed in the vehicle interior so that the small-sized hole is on the vehicle interior side, further improving sound absorption performance Can do.

  Here, when the mold is clamped, the tips of both convex molds do not contact each other, that is, a predetermined gap is formed between the convex portions. This gap becomes a burr formed inside the through-hole of the molded product, but the following effects are obtained because both convex portions do not come into contact with each other. One of them is that the convex part is provided on both the fixed mold and the movable mold, and the part where the burr is formed in the through hole is inside the through hole, and the burr protrudes outside the molded product. This is to eliminate the above-mentioned problems caused by peeling off of the film and removal by post-processing. The other is that the convex portions corresponding to each other at the time of mold clamping of the mold do not come into contact with each other, so that the repeated use can completely eliminate the deterioration of the convex portions due to the corresponding contact.

  In addition, the molded product molded by the molding die described above is made of expandable resin particles. When thermoplastic resin particles are used as the expandable resin particles, a styrene-modified polyethylene resin, a polystyrene resin, Polyethylene resin, polypropylene resin, or the like can be used. When a thermosetting resin is used as the foamable resin, a polyurethane resin or the like can be used. Among them, styrene-modified polyethylene resin resin particle foam moldings obtained by impregnating and polymerizing polyethylene resin particles with styrene monomers include polyethylene resin particle foam moldings and polypropylene resin particle foam moldings. Compared to the above, it is particularly preferable because it is excellent in dimensional stability and shape retention and is less likely to generate powder due to rubbing than a foamed molded product of polystyrene resin particles. The proportion of the styrene component in the styrene-modified polyethylene resin is 40 to 90% by weight, preferably 50 to 85% by weight, more preferably 55 to 75% by weight.

  When molding the lower limb impact absorbing pad, for example, a thermoplastic resin such as the above-mentioned styrene-modified polyethylene resin is impregnated with a foaming agent to form a foamable thermoplastic resin. Prefoamed particles are produced by prefoaming with heated steam or the like. Then, the pre-expanded particles are filled in the mold and foam-molded. Here, the expansion ratio of the floor spacer is preferably formed by pre-expanded particles adjusted within a range of 3 to 70 times, for example.

  Further, another embodiment of the molding die according to the present invention is a molding die for molding a molded product having a fixed die and a movable die and having a through hole, and is formed by the fixed die and the movable die. The cavity is provided with a first convex portion and a second convex portion for forming the through-hole at corresponding locations, and either the first convex portion or the second convex portion is provided. A concave groove in which the other convex part is loosely fitted is formed at one end, and in a posture where the fixed mold and the movable mold are clamped, a gap is formed between the concave groove and the other convex part. It is characterized by being formed.

  In the molding die of the present invention, the configuration in which the convex portions are provided at the corresponding positions of both the fixed die and the movable die is the same as the molding die described above, but at the tip of one convex portion is the molding die. When the mold is clamped, a concave groove is formed in which the other convex part is loosely fitted.

  Further, the other convex portion has a multi-stage shape including a convex portion having a relatively large cross section and a convex portion having a relatively small cross section provided at the tip thereof, and the convex portion having the small cross section is the concave portion. In the posture in which the fixed mold and the movable mold are clamped and the convex portion of the small cross section is loosely fitted in the concave groove, the first convex portion and the second convex portion are fitted in the groove. A form in which a gap is formed between the convex portions may be employed. Even in such a configuration, a predetermined gap is formed between the concave groove and the convex part loosely fitted thereto, and the problem of deterioration damage due to contact of both is not caused. .

  As can be understood from the above description, according to the molding die of the present invention, the convex portions provided at the corresponding positions of both the fixed die and the movable die are not brought into contact with each other when the molding die is clamped. Thus, burrs can be formed inside the through-hole formed in the molded product, and the problem of peeling off when the burrs come into contact with other products or manpower and removal by post-processing can be solved. Moreover, since both convex parts do not contact | abut, degradation of this convex part can be made hard to produce and a maintenance expense etc. can be reduced as much as possible.

  Embodiments of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view of an embodiment of a mold according to the present invention, FIG. 2 is a view taken along the line II-II of FIG. 1, and FIG. 3 is a floor spacer formed by the mold of FIG. . 4 and 5 are sectional views of another embodiment of the mold of the present invention, and FIG. 6 is a floor spacer formed by the mold of FIG.

  FIG. 1 is a cross-sectional view of an embodiment of a mold and shows a state during mold clamping. 2 is a view taken in the direction of arrows II-II in FIG. The mold 10 is generally composed of a box-shaped fixed mold 1 opened downward and a box-shaped movable mold 2 opened upward, and the ends of both outer peripheral sides 11 and 21 are clamped. A cavity space corresponding to the molded product is formed inside the parts in contact with each other.

  Protrusions 12 and 22 are provided at corresponding positions on both the fixed mold 1 and the movable mold 2 as shown in the figure, and a predetermined gap G is formed between the projecting parts 12 and 22 during mold clamping. It has become. The mold 10 shown in the figure is a form for molding a floor spacer having four sound absorbing through holes. As shown in FIG. 2, four protrusions are provided on both the fixed mold 1 and the movable mold 2. .. Are provided. Of course, the number of through-holes to be molded and the shape of the floor spacer may be other than shown.

  For example, pre-expanded particles R are manufactured by pre-expanding polystyrene resin with heated steam at a expansion ratio of 30 times, and the pre-expanded particles R are filled in the mold 10 and the mold 10 is heated for several seconds. Then, one side of the molded body is steam-heated for about 5 seconds, the other side is then steam-heated for about 5 seconds, both sides are further heated for about 10 seconds, and finally is allowed to cool for about 150 seconds. Thus, the floor spacer W shown in FIG. 3 is formed. The time required for each step is appropriately adjusted so that a floor spacer having a desired porosity is obtained.

  Four through holes W1,... Are formed in the floor spacer W, and burrs B formed by pre-expanded particles that have entered the gap G at the time of mold clamping shown in FIG. 1 are formed in the respective through holes W1. Will be.

  However, the burr B is formed inside the through hole W1, and never protrudes outside the floor spacer W.

  On the other hand, FIG. 4 shows another embodiment of the mold. This molding die 10A is composed of two-stage convex portions 13a and 13b in which the convex portion 13 provided on the fixed die 1A is reduced in diameter toward the movable die 2A side. A convex portion 23 having the same diameter as that of the portion 13a is provided, and a concave groove 23a is formed at the tip of the convex portion 23 in which the convex portion 13b is loosely fitted when the mold is clamped. A gap G is also formed between the concave groove 23a and the convex portion 13b, and between the convex portion 13a and the tip surface of the convex portion 23. There is no contact.

  Pre-expanded particles R similar to those described above are filled in the cavities, and the floor spacer shown in FIG. 3 is formed through predetermined foam molding. However, in the case of the mold 10A, depending on the size of the gap G, the pre-foamed particles may not enter the inside, and in this case, a ring shape protruding into the inside of the formed through hole. The burr is formed.

  FIG. 5 shows still another embodiment of the mold. In this molding die 10B, the convex portion 14 provided on the fixed die 1B has a truncated cone shape whose tip is reduced in diameter, and has a concave groove 24a that accommodates at least the truncated cone portion. Reference numeral 24 denotes a molding die provided on the movable die 2B. In the illustrated embodiment, the convex portion 24 has a relatively large diameter relative to the outer diameter of the convex portion 14. A gap G is also formed between the concave groove 24a and the convex portion 14, and the two do not come into contact with each other during mold clamping.

  In the drawing, the size t1 of the gap G is about 0.5 mm, the thickness t2 outside the concave groove 24a in the convex portion 24 is about 2 mm or more, and the non-reduced portion of the convex portion 14 is concave. The length (sliding length) t3 entering the groove 24a can be set to about 1 mm or more.

  A floor spacer WA molded by the mold 10B is shown in FIG. The through-hole WA1 formed in the floor spacer WA is formed into a multi-stage shape (two stages) when the outer diameters of the convex portions 14 and 24 are different. When the floor spacer WA is installed in the vehicle interior, the sound absorbing performance can be further enhanced by installing the floor spacer WA in the state shown in the drawing, that is, the small diameter portion of the through hole WA1 is on the vehicle interior side.

  According to the floor spacers W and WA formed by the molds 10, 10 </ b> A, and 10 </ b> B described above, the burrs B are formed inside the formed through holes W <b> 1 and WA <b> 1, and thus the burrs are peeled off and dust is generated. In addition, it is possible to eliminate the problem of deteriorating productivity due to the need for post-processing and removal due to poor appearance.

  Furthermore, since the corresponding convex parts of both the fixed mold and the movable mold do not come into contact with each other when the mold is clamped, both convex parts come into contact with each repeated use, and the convex parts wear and deteriorate. The problem that it becomes easy cannot occur. Therefore, the problem that the maintenance cost of a shaping | molding die, the replacement | exchange cost of the mold accompanying deterioration of a through-hole shaping | molding part, etc. increase like the conventional shaping | molding die can also be eliminated.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

It is sectional drawing of one Embodiment of the shaping | molding die of this invention. It is an II-II arrow line view of FIG. It is the floor spacer shape | molded by the shaping | molding die of FIG. It is sectional drawing of other embodiment of the shaping | molding die of this invention. It is sectional drawing of other embodiment of the shaping | molding die of this invention. FIG. 6 is a floor spacer molded by the mold of FIG. 5. FIG. (A) is sectional drawing to which the through-hole shaping | molding part of the conventional shaping | molding die was expanded, (b) is sectional drawing of a part of molded molded article.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Fixed type | mold, 11 ... Outer peripheral side, 12, 13, 14 ... Convex part, 2, 2A, 2B ... Movable type, 21 ... Outer peripheral side, 22, 23, 24 ... Convex part, 23a, 24a ... Groove, W, WA ... floor spacer, W1, WA1 ... through hole, R ... pre-foamed particle, G ... gap 11

Claims (3)

A mold having a fixed mold and a movable mold for molding a molded product having a through hole,
In the cavity formed by the fixed mold and the movable mold, a first convex portion and a second convex portion for forming the through hole are provided at corresponding locations,
A molding die characterized in that a gap is formed between the first convex portion and the second convex portion in a posture in which the fixed die and the movable die are clamped. A mold having a fixed mold and a movable mold for molding a molded product having a through hole,
In the cavity formed by the fixed mold and the movable mold, a first convex portion and a second convex portion for forming the through hole are provided at corresponding locations,
A concave groove into which the other convex portion is loosely fitted is formed at the tip of either the first convex portion or the second convex portion,
A molding die, wherein a gap is formed between the concave groove and the other convex portion in a posture in which the fixed die and the movable die are clamped. The other convex portion has a multi-stage shape composed of a convex portion having a relatively large cross section and a convex portion having a relatively small cross section provided at the tip thereof, and the convex portion having the small cross section is It is designed to be loosely fitted in the groove,
In a posture in which the fixed mold and the movable mold are clamped and the convex portion of the small cross section is loosely fitted in the concave groove, a gap is formed between the first convex portion and the second convex portion. The mold according to claim 2, wherein:

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