JPH06297501A - Molding method and die for hollow article - Google Patents

Abstract

PURPOSE:To provide a hollow article without a core and requiring no reheating by providing a projected part on the die face of one side opposite a recessed part provided on the die face of the other side, the recessed part and the projected part in reverse relation in separate places, molding two parts respectively, moving the die of one side and mutually joining the recessed parts by joining resin. CONSTITUTION:A rotary core 3 is fitted to a top force 1. One part of the rotary core 3 is formed in a projected shape and the other part thereof is formed in a recessed shape. One part of a bottom force 2 opposite to the projected shape is formed in a recessed shape and the other part of the bottom force 2 opposite to the recessed shape is formed in a projected shape. Both are joined to gether and synthetic resin is forcedby fed to the voids of a part and the other part through a sprue runner 6. Semi-spherical moldings A, A' are molded. After the top and bottom forces are opened, the sprue runner 6 is taken out and the rotary core 3 is rotated at 180 deg. and the moldings A, A' are put in a joining state and the top and bottom froces are closed. A this time, the seal rib 7 of the molding A is inserted into the V-shaped groove 8 of the molding A'. A seal block 4 is actuated and resin is forcedly fed to the voids 11 connected to the moldings A, A' through the sprue runner 6 and the moldings A, A' are joined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method and a molding die for molding a hollow product.

[0002]

2. Description of the Related Art Japanese Patent Publication No. 49-26068 has been disclosed as a conventional molding technique for hollow molded articles.

Japanese Examined Patent Publication No. 49-26068 relates to a hollow ball molding machine for ball games. The construction and method of use will be described below with reference to FIGS. 7 to 10.

An oil cylinder 2 is provided above and below the molding machine 1.
2 has an upper concave mold 3 and a lower concave mold 4 connected to each other. The upper concave mold 3 and the lower concave mold 4 are opposed to each other, and hemispherical inner walls 5 and 6 are formed on the facing surfaces. It is better to provide embossed patterns 9 and 10 on the inner walls 5 and 6, respectively. Furthermore, upper concave mold 3,
On the opposite surface of No. 4, a press-fitting machine 21 for supplying the raw material for the outer layer of the ball, which will be described later, and air for the ball base, an air injection rod 22.
Insertion grooves 7 and 8 that can be inserted are formed, and serve as insertion holes when the pair of concave molds 3 and 4 are closed.

Further, the upper concave molds 3 and 4 are provided with a heating passage 11 for passing steam or hot water and a cooling passage 12 for passing cooling water.

On the other hand, a spherical core 14 supported by support columns 13 and having a pivoting portion 18 is installed at a substantially central portion of the molding machine 1, that is, at an intermediate position between the upper and lower concave molds 3 and 4.
This is configured to be rotatable. The spherical core 14 is formed by attaching a pair of hemispherical molds 15 and 15 to a base material 16 and holding a fastener 17 such as a bolt or a screw.
Inside, a heating passage 19 and a cooling air passage 20 are provided.

A press-fitting machine 21 or an injection machine for supplying the raw material for the outer layer of the ball is set on the left and right of the molding machine 1, and this supply port 21 'is provided between the spherical core 14 and the upper and lower concave molds 3, 4. It is a structure that can be moved to and inserted into.

Next, the operation of the present invention will be described. To mold a pair of hemispherical ball outer layers A and A ', the upper concave metal molds 3 and 4 are the oil cylinders 2 and 2 shown in FIG. 8 is engaged with the spherical core 14 as shown in FIG. 8 to form a gap between the spherical surface of the spherical core 14 and the inner walls 5, 6 of the upper and lower concave molds 3, 4 and press fit into the gap. Supply port 21 'of machine 21
The raw material of rubber or synthetic resin is press-fitted to form the two-part ball outer layers A and A'made of unvulcanized rubber or semi-gelled resin. Steam or hot water is passed through the heating passages 11 and 19 of each mold at the time of this molding, and the surface temperature of the upper and lower concave molds 3 and 4 is set to about 90 ° C.
It is necessary to raise the surface temperature of No. 4 slightly above 90 ° C.

Next, after the hemispherical ball outer layers A and A'are formed, the upper and lower concave molds 3 and 4 are replaced by the oil cylinder 2,
The ball outer layers A and A'are opened by the action of 2,
It is separated from the spherical core 14 while being attached to the inner walls 5, 6 of the lower concave molds 3, 4. Thus, as means for allowing the outer layers A, A'of the ball to remain on the upper and lower concave molds 3, 4 side, the embossed patterns 9, 10 formed on the inner walls 5, 6 are used for the heating temperature in addition to the geometrical means. Physical means for lowering the temperature of the lower concave molds 3 and 4 above the core 14 and chemical means for applying a release agent such as zinc sanarate to the circumferential surface of the spherical core 14 are taken.

Next, as shown in FIG. 9, the spherical core 14 is rotated to the outside of the molding machine 1, and the ball base B molded by another machine is positioned at the center of the molding machine. The ball base B has a tube a inside and is provided with a reinforcing layer b around which cloth or nylon thread is wound. Thus, as shown in FIG. 10, a pair of upper and lower concave molds 3 and 4 in which the hemispherical ball outer layers A and A'are left, are closed with the ball base B sandwiched therebetween, and are provided on the ball base B. 5-6 kg / cm ² of air is applied from the air injection rod 22 to bring the ball base B into close contact with the ball outer layers A and A ′.
The upper and lower concave molds 3 and 4 are heated again (around 140 ° C.) to vulcanize or gelate the unvulcanized or semi-gelled ball outer layer to form the ball base B into the ball outer layers A and A ′. The ball is completed by fusing.

Next, the pair of upper and lower concave molds 3 and 4 containing the balls are cooled, and the air in the ball base B is discharged, and the mold is opened and the balls are taken out.

[0012]

The above-mentioned conventional ball forming method has the following problems to be solved.

That is, the conventional method requires a core to obtain the ball outer layers A and A'molded by the upper concave mold 3 and the lower concave mold 4. In addition, when the outer ball layers A and A'are joined, it is necessary to reheat the upper concave mold 3 and the lower concave mold 4 to gel and fuse them.
There is a problem that the shape of A'cannot be retained.

An object of the present invention is to provide a molding method and a molding die for hollow articles which do not require a special core and do not need to reheat the outer layers A and A'of balls and the like.

[0015]

As a means for solving the above problems, the present invention intends to provide a method for molding a hollow article as described in (1) below and a molding die for a hollow article as described in (2) below. It is a thing.

(1) In the method of molding a hollow product, which comprises molding two parts of a hollow body made of a resin or the like in a divided shape, and then joining the faces corresponding to the divided faces to each other to form a hollow molded product. One of the two possible molds is provided with a concave portion on one of the facing surfaces of the mold so that one of the two parts can be molded, and a convex portion corresponding to the core is provided on the facing surface of the other mold corresponding to the concave portion. Further, a convex portion corresponding to a core is provided at another place of the facing surface of one mold so that the other of the two parts can be molded, and a concave portion is formed on the facing surface of the other mold corresponding to the convex portion. After providing a required annular gap on the outer periphery of the facing surface of either or both of the corresponding convex portions of the concave portions, a resin or the like is injected between the convex portions of the concave portions to form two parts. , Then, separate the two molds while leaving the same molded product in each recess so that the other recess accurately faces one recess. A hollow product characterized by moving one of the molds and bringing the two molds into contact with each other again, and then injecting a bonding resin into the annular space to bond each molded product to an integral hollow molded product. Molding method.

(2) After molding two parts of a hollow body divided shape made of resin or the like, the surfaces corresponding to the divided surfaces are joined to each other to form a hollow molded article. Two molds that are separable, a recess that is provided in one of the molds so that one of the two parts can be molded, and a mold that faces the other mold corresponding to the recess. The above-mentioned convex portion corresponding to the core and the above-mentioned 2
A convex portion corresponding to the core provided so that the other of the parts can be molded,
A concave portion provided on the facing surface of the other mold corresponding to the convex portion, and a required annular void provided on the outer periphery on either or both of the corresponding concave portion convex portions, or one of the facing surfaces, A molding die for a hollow product, comprising: a moving means for moving either one of the two dies so that the two recesses face each other and can coincide with each other.

As is clear from the description, the "two dies" in the above have a function as a set, so for example, two dies are called an upper die and a lower die. It is free to call both molds and one mold.

[0019]

Since the present invention is constructed as described above, it has the following actions.

That is, a recess is provided in the facing surface of one of the two molds that can be brought into contact with and separated from the facing surface so that one of the two parts can be molded, and the other mold is opposed to the corresponding recess. Since the convex portion corresponding to the core is provided on the surface and the concave portion and the convex portion are provided at different positions on the same facing surface so that the other of the two parts can be molded, the concave portion and the convex portion are provided in reverse relation. Mold two parts each with the convex portion of the concave part, separate the two molds while leaving the same molded product in each concave part, move one mold so that the concave parts face each other, and again press both molds. When abutted, the two parts will have the same shape as one hollow molded product.

On the other hand, since an annular gap is provided on the outer periphery of either or both of the convex portions of each concave portion of the mold, the annular gap is provided in a state where the concave portions face and abut each other. By injecting the bonding resin into the two moldings, the two molded products remaining in both recesses are bonded to form one hollow molded product.

That is, it is possible to obtain a joined hollow product which does not require a special core and is not heated.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of an embodiment of the present invention will be described with reference to FIGS.

The description will first be made on the molding die used in the method of this embodiment, and then the method of molding a hollow article using the molding die.

FIG. 1 is a molding product (primary molding product) in which an upper mold 1 and a lower mold 2 which are molding dies used in the method of this embodiment are hemispherical.
FIG. 2 is a side sectional view showing a state where A and A ′ are molded.
FIG. 3 is a side sectional view showing a state where the mold is opened up and down from the state of FIG.
2 is a side sectional view of the state in which the upper die is horizontally rotated 180 ° in the state of FIG. 2, FIG. 4 is a side sectional view of the state in which the die is vertically closed from the state of FIG. 3, and FIG. 5 is a view near the left end of FIG. FIG. 6 is an enlarged view of a portion, and FIG. 6 is a side sectional view of the state in which the mold is opened up and down from the state of FIG. That is, the hollow molded article 1 according to the method of this example
It is a figure of the state where 2 was obtained.

In FIG. 1, 1 is an upper die, 2 is a lower die and an upper die 1
A rotary core 3 is attached to the. The rotating core 3 has a structure capable of rotating around a spool runner 6 which is provided at the center of the upper mold 1 and a resin and through which resin passes.

The lower mold 2 is provided with a seal block 4 and an ejector pin 5. The a-part of the rotating core 3 has a convex shape, and the b-part has a concave shape.
The part (a) has a concave shape and the part (b) has a convex shape. When the upper mold 1 and the lower mold 2 are combined with each other, a gap is formed between the upper part 1 and the lower part, and the spool runner 6 is passed through this gap. After press-fitting to form a hemispherical shaped product A, A'corresponding to dividing the sphere into two parts, and then connecting the parts A, A'to each other at the corresponding part of the division, a spherical shaped product is obtained. ing.

A seal rib 7 is formed on the molded product A, and a V-shaped groove 8 is molded on the molded product A '. Further, both the molded products A and A'are provided with ribs 9 and 10 to prevent them from being left on the rotary core 3 and the lower mold 2 and to be changed by molding shrinkage.

Next, a hollow molded product 12 is produced by using the above molding die.
A method of molding the will be described. Molding is as described above
First, each hemispherical molded product A, A'which is a primary molded product is molded, and the upper mold 1 is formed without removing them from the molding die.
The product is rotated horizontally by 80 ° so that the molded products A and A'are opposed to each other on the surface corresponding to the division of the sphere, and the mold is closed to obtain a spherical hollow molded product.

As shown in FIG. 1, synthetic resin is press-fitted into the upper and lower gaps formed in the upper and lower molds 1 and 2 through the spool runner 6 to form hemispherical molded products A and A. ′ Is first molded.

After molding the molded products A and A ', the mold is opened as shown in FIG. 2, the spool runner 6 is taken out, and the rotary core 3 is rotated 180 ° in the horizontal plane as shown in FIG. The mold is closed as shown in FIG. At this time, as shown in FIG. 5, the sealing rib 7 of the molded product A is inserted into the V-shaped groove 8 of the molded product A '. After the mold is closed, the seal block 4 is actuated to form the space 11 in the portion where the molded products A and A'are joined together, as shown in FIGS. Synthetic resin is pressed into the space 11 through the spool runner 6. At this time, the seal rib 7 prevents the resin from leaking inward. The molded products A and A'are joined by the resin press-fitted into the space 11 to form the hollow molded product 12.
Next, as shown in FIG. 6, after the mold is opened, the ejector pin 5
The hollow molded article 12 is extruded by.

As described above, according to the method of this embodiment, one of the contact surfaces of the upper mold 1 (specifically, its rotating core 3) and the lower mold 2 has a concave portion on one side, and a convex portion corresponding to the core on the other side. On the other hand, conversely, a convex portion corresponding to the core is provided on one side, a concave portion is provided on the other side, and a sealing rib is provided so as to generate a space 11 which is an annular space. After the molded products A and A'are obtained in the gaps between the two parts, the molds are opened while leaving them in the recesses, and the rotary core 3 is rotated in the horizontal plane to bring the recesses into contact with each other to face each other. The synthetic resin is press-fitted into the part 11, and the molded product A,
Since the hollow molded product 12 is obtained by joining A ', there is an advantage that a core is not required and heating is not required for joining.

[0033]

Since the present invention is constructed as described above, it has the following effects.

That is, according to the present invention, there is no need for a hollow core which serves as a base for molding a hollow product, and there is no need to heat a mold for joining molded products divided into two parts.
The hollow molded product can be easily molded in the same die consisting of one set, and the hollow molded product can be obtained at extremely low cost.

[Brief description of drawings]

FIG. 1 is a side cross-sectional view of a state of primary molding with a mold according to a method of an embodiment of the present invention,

FIG. 2 is a side sectional view showing a state in which the spool is extruded after the primary molding is performed in the above-described embodiment,

FIG. 3 is a side sectional view of the upper rotary core rotated 180 ° in the above embodiment,

FIG. 4 is a side cross-sectional view showing a state in which the rotary core has been rotated and the mold has been closed and secondary molding has been carried out,

FIG. 5 is an enlarged view of a connecting portion between the upper concave part and the lower concave part shown in FIG. 4;

FIG. 6 is a side sectional view showing a state in which the mold is opened after the secondary molding and the molded product is extruded in the above-mentioned embodiment,

FIG. 7 is a side sectional view of a conventional example immediately before forming an outer layer of a ball (hemispherical shape),

FIG. 8 is a side cross-sectional view during molding of the ball outer layer of the above-mentioned conventional example,

FIG. 9 is a side cross-sectional view immediately after molding the outer layer of the ball of the above-mentioned conventional example (before inserting the ball base),

FIG. 10 is a side cross-sectional view during the thermocompression molding for inserting the ball bases into the outer layers of the balls of the conventional example and joining them together.

[Explanation of symbols]

 1 Upper mold 2 Lower mold 3 Rotating core 4 Seal block 5 Ejector pin 6 Spool runner 7 Seal rib 8 V type groove 9,10 Rib 11 Space part 12 Hollow molded product

Claims (2)

[Claims] 1. A method of molding a hollow product, comprising molding two parts of a hollow body made of resin or the like into a hollow body and then joining the faces corresponding to the divided faces to form a hollow molded product. A recess is provided on one of the two molds facing each other so that one of the two parts can be molded, and a corresponding protrusion is provided on the facing surface of the other mold corresponding to the recess. Further, a convex portion corresponding to a core is provided at another place of the facing surface of one mold so that the other of the two parts can be molded, and a concave portion is formed on the facing surface of the other mold corresponding to the convex portion. After providing a required annular space on the outer periphery of the facing surface of either or both of the corresponding convex portions of the concave portion provided, a resin or the like is injected between the convex portions of the concave portions to form two parts, Then, the two molds are separated while leaving the respective molded products in the respective recesses, and one of them is placed so that the other recess accurately faces the other recess. Molding of a hollow product characterized by moving one mold and bringing the two molds into contact with each other again, and then injecting a bonding resin into the annular space to bond each molded product to an integral hollow molded product Method. 2. A molding die for a hollow product, which is obtained by molding two parts of a hollow body divided shape made of a resin or the like, and then joining the faces corresponding to the divided faces to each other to form a hollow molded product. Two possible molds, a concave part provided on one of the molds facing each other so that one of the two parts can be molded, and a corresponding concave part provided on the facing surface of the other mold. Corresponding to the convex part corresponding to the core and the convex part corresponding to the core provided at another place of the facing surface of the one mold so that the other of the two parts can be molded. A recess provided on the opposite surface of the other mold,
Either one of the two molds is moved so that the required annular gap provided on the outer periphery of the facing surface of either or both of the corresponding concave portions and the corresponding concave portions face each other. A molding die for a hollow product, comprising: