JP2000043102A - Die and method for forming hollow molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die and a method for forming a hollow molding in which time of a molding cycle is shortened in the case of producing the hollow molding and also both forming of a split body and melt-stuck joining of the split half bodies after forming are simultaneously performed in such a state that injection amount of resin is not changed but is constant. SOLUTION: The movable die 1 can be moved in the vertical direction and in the lateral direction for a stationary die 3. In a first position, molten resin injected and poured from a first and a second respective resin pouring gates 35, 37 is respectively supplied to molding spaces 21, 23 and split half bodies of a hollow molding are formed. Simultaneously, the molten resin is supplied to grooves 29 in the circumference of the already formed split half bodies 25, 27 and the split half bodies 25, 27 are mutually melt-stuck and joined and a hollow molding is completed. The movable die 1 is moved from the first position to a second position in which the split half bodies formed in the molding spaces 21, 23 are mutually joined. Injection operation is similarly performed and both forming of the semisplit bodies and melt-sticking and joining of mutual split half bodies are simultaneously performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a hollow molded article which is formed by forming a pair of halves and then welding and joining the periphery of the joint between the halves when manufacturing a hollow molded article. It relates to a mold and a molding method.

[0002]

SUMMARY OF THE INVENTION The present invention reduces the molding cycle time when manufacturing a hollow molded article, and forms a half-split body while keeping the injection amount of molten resin constant without changing it. An object of the present invention is to enable welding of a joint.

[0003]

In order to achieve the above-mentioned object, according to the present invention, a first concave portion and a second concave portion are provided on mutually opposing surfaces of a first mold and a second mold. Are provided in parallel with each other, and a first convex portion and a second convex portion are respectively provided on both sides in the parallel direction of the two concave portions, and the first convex portion of the first mold is provided. The concave part and the first convex part of the second mold are aligned to form a molding space in which a half body of the hollow molded article is molded, and the second convex part of the first mold is formed. And the second concave portion of the second mold are aligned to form a molding space in which a half body of the hollow molded article is molded, and the second concave portion of the first mold and the second concave portion are formed. A first position in which the first concave portions of the mold are aligned with each other so that the end faces of the respective half bodies which are housed in the respective concave portions after molding are joined to each other; The second concave portion and a second mold 2
Are aligned with each other to form a molding space in which a half body of the hollow molded article is molded, and the first convex part of the first mold and the first concave part of the second mold are formed. Are aligned with each other to form a molding space in which a half body of the hollow molded article is molded, and the first concave portion of the first mold and the second concave portion of the second mold are mutually reciprocated. The first mold and the second mold can be set at a second position where the end faces of the respective halves housed after being molded in the respective concave mold portions are joined together. Are formed so as to be movable with respect to each other, and in both the first position and the second position, a molding space for molding the periphery of the mutually joined half-pieces and the half-pieces located on both sides thereof Are connected to each other by a communication passage through which the injected molten resin is supplied.

According to the molding die for a hollow molded article having such a configuration, the first position is defined between the first concave portion of the first die and the first convex portion of the second die. The molten resin is injected and injected into the molding space of the first mold and the molding space between the second convex mold part of the first mold and the second concave mold part of the second mold, respectively. After molding, the halves are molded, and at the same time, the end faces are joined to each other within the second concave portion of the first mold and the first concave portion of the second mold that are aligned with each other. The molten resin is injected and injected around the joint of each half
The halves after this molding are welded to each other to complete a hollow molded article.

In a state where the first mold and the second mold are relatively moved from the first position to the second position, the second recess of the first mold and the second mold are formed. The molten resin is filled in the molding space between the second convex portion and the molding space between the first convex portion of the first mold and the first concave portion of the second mold, respectively. The injection molding is performed to form a half-piece of the hollow molded article, and at the same time, the first half of the first die and the second half of the second die are aligned with each other. A molten resin is injected and injected around a joint portion of each of the halves molded at the first position where the end faces are joined to each other, and the molded halves are welded to each other to form a hollow molded article. Is completed.

According to a second aspect of the present invention, in the configuration of the first aspect, either one of the first mold and the second mold has:
From the first convex portion and the first concave portion, between the first concave portion and the second concave portion, and between the second concave portion and the second convex portion, Resin injection gates each capable of injecting and injecting the molten resin toward the passage were provided.

According to the above configuration, the molten resin is injected and injected from the resin injection gate, whereby the molten resin is supplied to the periphery of the joints of the halves joined to each other through the communication path, and the halves are welded to each other. At the same time, the molten resin is supplied to the two molding spaces for molding the halves through the communication passages to form a pair of halves.

According to a third aspect of the present invention, in the configuration of the second aspect, the resin injection gate not communicating with the communication passage at each position is closed by the end surface of the other mold.

According to the above configuration, the molten resin is not supplied from the unnecessary resin injection gate to the molding space and the periphery of the joint, but the molten resin is supplied only from the necessary resin injection gate to the molding space and the periphery of the joint. You.

According to a fourth aspect of the present invention, in the configuration of the second aspect of the present invention, an on-off valve for preventing the molten resin from flowing into the resin injection gate not communicating with the communication passage at each position is provided.

[0011] According to the above construction, the molten resin is not supplied from the unnecessary resin injection gate to the vicinity of the molding space and the joining portion due to the opening / closing operation of the on-off valve. A molten resin is supplied.

According to a fifth aspect of the present invention, in the configuration of the second aspect of the present invention, a resin injection gate between the first convex portion and the first concave portion, and a second concave portion and the second convex portion. A resin injection gate between the mold portion and the resin injection gate is provided with a flow control valve capable of adjusting the inflow amount of the molten resin. Of the two resin injection gates, the resin injection gate that is not connected to the communication path at each position is:
It communicates with an auxiliary communication passage communicating with a molding space adjacent to the resin injection gate.

According to the above construction, the injected molten resin is supplied from the resin injection gate communicating with the communication passage to the periphery of the joint between the half bodies through the communication passage, and
The molten resin is also supplied to the two molding spaces, and at the same time, the injected molten resin is supplied from the resin injection gate communicating with the auxiliary communication passage to one molding space adjacent thereto through the auxiliary communication passage. At this time, for example, when there is a difference between the two, such as the volume of one molding space is larger than the volume of the other molding space, the opening degree of the flow control valve of the resin injection gate communicating with the auxiliary communication passage is adjusted. By adjusting the resin inflow amount, the filling time of the molten resin into the two molding spaces is made uniform.

According to a sixth aspect of the present invention, the first mold and the second mold
Two first concave portions and two second concave portions are provided in parallel on the mutually facing surfaces of the mold, and a first convex portion and a second convex portion are provided on both sides in the parallel direction of the two concave portions. Are provided, and the first concave portion of the first mold and the first convex portion of the second mold are aligned to form a molding space, and the first mold is formed. Of the second mold and the second mold of the second mold
A molding space is formed by aligning with the concave part of
The second concave portion of the first die and the first concave portion of the second die are aligned with each other, and the end faces of the respective half bodies housed in the respective concave portions after being molded are joined. In the first position, the molten resin is injected and injected into each of the molding spaces to form a half of the hollow molded article, and at the same time, the molten resin is injected around the joints of the halves where the end surfaces are joined to each other. The first mold and the second mold are relatively moved from the first position by injecting and welding the half halves to each other, so that the second concave part of the first mold and the second concave part are formed. A molding space is formed in alignment with the second convex part of the second mold, and the first mold of the first mold is formed.
And the first concave portion of the second mold are aligned to form a molding space, and the first concave portion of the first mold and the second concave portion of the second mold are formed. At the second position where the concave portions are aligned with each other and the end faces of the respective halves housed after being molded in these concave portions are joined to each other, the molten resin is injected and injected into each of the molding spaces, and the hollow molding is performed. Simultaneously with the molding of the halves of the product, the molten resin is injected and injected around the joints of the halves where the end faces are joined to each other to weld the halves together.

According to the molding method described above, the welded joints of the molded halves are formed by one injection operation of the molten resin, and at the same time, a pair of halves to be welded and joined by the next injection operation are formed. Molded.

According to a seventh aspect of the present invention, in the molding method of the sixth aspect, in any of the first position and the second position, when the filling of the molten resin into one molding space is completed, the other is completed. When the remaining filling operation of the molding space is performed, the injection speed of the molten resin is increased from the beginning.

According to the molding method, when there is a difference between the two molding spaces, for example, when the volume of one molding space is larger than the volume of the other molding space, the filling of the resin into the molding space having a small volume is completed. At this time, the large molding space
At this point, the injection speed is increased from the beginning, and the remaining molten resin is supplied to the molding space having a large volume.

The invention of claim 8 is to form one half of the hollow molded product in the first molding space between the first die and the one surface, and to form the second half with the second die. The second between the faces
An intermediate mold for molding the other half of the hollow molded article in the molding space, and a resin injection for primary injection capable of simultaneously supplying molten resin to each of the first and second molding spaces. A gate is provided, and the intermediate mold is provided with a half mold forming position located between the first mold and the second mold, and a half mold at a position deviating from a position between the molds. It is configured to be movable between a welding position and a molten resin is injected into one of the first and second dies so as to weld a joint between the respective halves of the hollow molded article. A secondary injection resin injection gate is provided.

According to the above configuration, the intermediate mold is located at the half mold forming position between the first and second molding dies,
The molten resin is simultaneously supplied to the second molding space from the resin injection gate for primary injection of the intermediate mold to form a pair of halves. In a state where the molds are moved to the welding position, the first and second dies are brought closer to each other to join the pair of halves together. Thereafter, a molten resin is supplied from the secondary injection resin injection gate to weld the joint between the half bodies.

According to a ninth aspect of the present invention, in the configuration of the eighth aspect of the present invention, the flow rate adjustment is performed such that the amount of the molten resin supplied to the first and second molding spaces can be adjusted in the primary injection resin injection gate. A valve is provided.

According to the above construction, the filling time of the molten resin into each of the first and second molding spaces is made uniform by adjusting the flow control valve. Further, by adjusting the flow control valve so as to close the flow path to any one of the first and second molding spaces, the supply of the molten resin to each of the first and second molding spaces is separately performed. I can do it.

According to a tenth aspect of the present invention, a first molding space between one surface of the intermediate mold and the first mold and a first molding space between the other surface of the intermediate mold and the second mold are provided. In the second molding space, a molten resin is simultaneously supplied from a primary injection resin injection gate provided in the intermediate mold to form a pair of halves of a hollow molded product. The first and second dies are clamped in a state where the first and second dies are moved to positions separated from the first and second dies. In addition, a molding method is provided in which a molten resin is supplied from a secondary injection resin injection gate provided in one of the first and second molds to weld and join the joint between the pair of half bodies.

According to the above-mentioned molding method, a pair of halves are molded simultaneously by one injection operation, and the entire molding cycle time is shortened.

According to an eleventh aspect of the present invention, in the molding method of the tenth aspect, the first and second dies and the intermediate mold are located at predetermined positions before the mold clamping operation. After supplying the molten resin to the first and second molding spaces from above, a mold clamping operation is performed.

According to the molding method, the molten resin is supplied while the mold is opened to some extent, so that the molten resin sufficiently enters the terminals of the first and second molding spaces,
By performing mold clamping after supplying the molten resin, a thinner hollow molded article is formed.

[0026]

According to the first aspect of the present invention, the welding and joining of the halves after molding and the forming of a pair of halves to be welded and joined in the next injection operation are performed at one time of the molten resin. Since it can be performed in the injection process, the cycle time for molding the hollow molded article can be shortened, and the molding of a pair of halves and the welding and joining of the halves are performed without changing the injection amount. Since it can be performed, no special modification of the injection molding machine is required, and the existing molding machine can be used.

According to the second aspect of the present invention, the molding of the pair of halves and the welding and joining of the halves are simultaneously performed by injecting and injecting the molten resin from the resin injection gate toward the communication path. be able to.

According to the third aspect of the present invention, the resin injection gate that is not in communication with the communication path is closed by the end face of the other mold. The molten resin can be supplied only from the necessary resin injection gate without supplying the molten resin to the resin.

According to the fourth aspect of the present invention, since the on-off valve for preventing the resin from flowing into the resin injection gate that is not in communication with the communication path is provided, unnecessary opening of the resin injection gate can be prevented by the on-off operation of the on-off valve. No molten resin is supplied to the molding space and the periphery of the joint, and the molten resin can be supplied only from a necessary resin injection gate.

According to the fifth aspect of the present invention, by controlling the opening of the flow control valve of the resin injection gate communicating with the auxiliary communication passage to adjust the resin inflow amount, the communication with the auxiliary communication passage is achieved. Even if the volume of the molding space is larger than the other molding space, even if there is a difference between the two, the filling time of the molten resin in the two molding spaces can be made uniform and the occurrence of unfilled parts can be prevented. can do.

According to the sixth aspect of the present invention, the welding and joining of the halves after molding and the molding of a pair of halves to be welded and joined in the next injection operation are performed by one injection operation of the molten resin. In addition to shortening the cycle time for molding a hollow molded product, the molding of a pair of half-pieces and the welding and joining of the half-pieces can be performed while keeping the injection amount constant. Therefore, no special modification or the like is required as an injection molding machine, and an existing molding machine can be used.

According to the seventh aspect of the present invention, when there is a difference between the two molding spaces, such as when the volume of one molding space is larger than the volume of the other molding space, the filling of the resin into the molding space having a small volume is completed. At this point, the injection speed is increased from the beginning, and the remaining molten resin is supplied to the large molding space in this state, so that the supply time of the remaining molten resin is performed at the same speed. This makes it possible to suppress the overfilling of the molten resin into the molding space of a small volume that has been shortened and has already been filled.

According to the eighth aspect of the present invention, the molten resin is simultaneously supplied to the first and second molding spaces from the resin injection gate for the primary injection of the intermediate mold, and the pair of halves are simultaneously injected. Since molding can be performed, the cycle time for molding the hollow molded article can be reduced.

According to the ninth aspect of the present invention, the filling time of the molten resin into each of the first and second molding spaces can be made uniform by adjusting the flow control valve. Can be prevented.

According to the tenth aspect of the present invention, a pair of halves can be simultaneously molded by a single injection operation, so that the cycle time for molding a hollow molded article can be reduced.

According to the eleventh aspect of the present invention, the molten resin is supplied while the mold is opened to a certain extent, whereby the first and second molds are supplied.
The molten resin sufficiently penetrates to the end of each molding space, and a high quality hollow molded product without underfill is obtained,
Since injection compression is performed in which mold clamping is performed after injection, a thinner hollow molded article can be formed, and material costs can be reduced.

[0037]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a molding die for a hollow molded product according to an embodiment of the present invention.
The movable mold 1 includes a movable mold 1 as a first mold and a fixed mold 3 as a second mold. The movable mold 1 is movable in the vertical direction in FIG. It can also move in the left-right direction so as to approach and separate from the mold 3.

On the surface of the movable mold 1 facing the fixed mold 3, a movable first concave portion 5 and a movable second concave portion 7 are vertically arranged in parallel at the center in the vertical direction in the figure. Are formed, the movable-side first convex portion 9 is formed on the upper side, and the movable-side second convex portion 11 is formed on the lower side.

Similarly to the movable mold 1, the fixed-side first concave portion 13 and the fixed-side second concave portion 15 are provided at the center in the vertical direction on the surface of the fixed mold 3 facing the movable mold 1. And a fixed-side first convex portion 17 and a fixed-side second convex portion 19 are formed on both upper and lower ends.

Each of the first and second convex portions 9 and 17 and the second and second convex portions 11 and 19 on the movable side and the fixed side is aligned with the concave portion on the other side. Annular projections 9a and 17 which come into close contact with the peripheral wall of the opening
a, 11a and 19a are formed respectively.

FIG. 1 shows that the movable first concave portion 5 and the fixed first convex portion 17 are aligned with each other to form a molding space 21, and the movable second convex portion 11 is fixed to the movable second convex portion 11. The molding space 23 is formed by aligning with the second concave portion 15 on the side, and the second concave portion 7 on the movable side and the first concave portion 13 on the fixed side are aligned with each other. 1 shows a first position in which the end faces of the half bodies 25 and 27 constituting the hollow molded product after being housed are joined to each other.

A groove 29 is formed around the joint between the halves 25 and 27, and the groove 29 and the molding space 2 are formed.
1 and 23 communicate with each other by communication paths 31 and 33 formed between the movable mold 1 and the fixed mold 3, respectively.

In the fixed mold 3, a first resin injection gate 35 is provided between the fixed-side first convex portion 17 and the fixed-side first concave portion 13. 13 and fixed side second
A second resin injection gate 37 between the fixed-side second concave portion 15 and the fixed-side second convex portion 19; Each is formed.

Each of the resin injection gates 35, 37, 39 is connected to a resin injection pipe 35a, 37a, 39a, respectively, and these are connected to a common resin injection pipe 40 so that molten resin can be supplied from outside as indicated by arrow A. It is what is injected and injected. In the first position shown in FIG. 1, the first resin injection gate 35 communicates with the communication passage 31, the second resin injection gate 37 communicates with the communication passage 33, and the third resin injection gate 39 is The movable mold 1 is in close contact with the end face of the movable mold 1 and is closed.

When the molten resin is injected and injected at the first position as shown by the arrow A, the injected molten resin passes through the first resin injection port 35 as shown in FIG. At the same time, it flows into the communication passage 33 through the second resin injection port 37. The molten resin flowing into the communication passage 31 also flows into the groove 29 at the same time as flowing into the molding space 21, and the resin flowing into the communication passage 33 flows into the groove 29 at the same time as flowing into the molding space 23.

After the injection operation is completed and the injected molten resin is cooled and solidified, the movable mold 1 is moved in a direction away from the fixed mold 3 and opened as shown in FIG. Half molded body 4 of a hollow molded product solidified in space 21
1 is housed in the first concave portion 5 of the movable mold 1, and is also a hollow molded product half body 43 solidified in the molding space 23.
Is accommodated in the second concave portion 15 of the fixed mold 3. Each of the half bodies 41 and 43 has a concave portion 41a and 43a, respectively. Around the opening of the concave portion 41a and 43a, the projection 17a of the fixed first convex portion 17 and the movable second convex portion are provided. It has groove forming portions 41b and 43b formed by the mold portions 11a, respectively.

On the other hand, when the molten resin injected into the groove 29 is solidified, the half body 25 housed in the movable second concave portion 7 and the fixed half first concave portion 13 are formed. The housed half body 27 is welded and joined by the welding portion 45, whereby the hollow molded article 47 is completed. Reference numerals 49 and 51 indicate that the molten resin in the first resin injection gate 35 and the communication passage 31 and the molten resin in the second resin injection gate 37 and the communication passage 33 are cooled and solidified, respectively. It is a piece of resin.

Next, from the state shown in FIG. 3, the movable mold 1 is moved downward and close to the fixed mold 3 to close the mold, thereby setting the second position shown in FIG. In this second position, the movable-side second concave portion 7 and the fixed-side second convex portion 19 are aligned to form a molding space 53, and the movable-side first convex portion 9 is fixed to the movable-side first convex portion 9. The molding space 55 is formed by aligning with the first concave portion 13 on the side, and the first concave portion 5 on the movable side and the second concave portion 15 on the fixed side are aligned with each other. The end faces of the molded half-pieces 41 and 43 accommodated in the first and second molds are joined to each other.

The molding space 53 and the molding space 55 are equal in volume to each other, and they are equal in volume to the molding space 21 and the molding space 23 in the first position.

The groove 57 formed by the groove forming portions 41b and 43b is provided around the joint between the half bodies 41 and 43.
The groove 57 and the molding spaces 53 and 55 are connected to each other by communication passages 59 and 61 formed between the movable mold 1 and the fixed mold 3, respectively.

In the second position shown in FIG.
The second resin injection gate 37 communicates with the communication passage 61, and the third resin injection gate 39 communicates with the communication passage 59.
The resin injection gate 35 is in close contact with the end face of the movable mold 1 and is closed.

When the molten resin is injected and injected in the second position in the same manner as in the first position in FIG. 1, the injected molten resin is moved to the second position as shown in FIG.
Flows into the communication passage 61 through the resin injection port 37 of the above, and also flows into the communication path 59 through the third resin injection port 39. The molten resin flowing into the communication path 61 flows into the molding space 55 and also into the groove 57 at the same time, and the resin flowing into the communication path 59 flows into the molding space 53 and the groove 57 at the same time.
Also flows into.

After the injection operation is completed and the injected molten resin is cooled and solidified, the movable mold 1 is moved in a direction away from the fixed mold 3 as in FIG. Open. As a result, the halves of the hollow molded article are formed in the molding space 53 and the molding space 55, respectively, and the halves formed in the first position by the molten resin solidified in the grooves 57. 41 and half body 4
3 are welded and joined, whereby a hollow molded product is completed.

As described above, in the above embodiment, the injection operation of the molten resin is performed in a state where the positional relationship of the movable mold 1 with respect to the fixed mold 3 is alternately switched between the first position and the second position. By doing so, the molding of a pair of halves forming the hollow molded article and the welding and joining of the halves after molding can be performed simultaneously, so that the molding cycle time is reduced. In addition, in any of the first and second positions, the resin injection amount does not need to be changed and can be molded in a fixed state, so that no special modification or the like is required as an injection molding machine. It is possible to respond.

Further, since the third resin injection gate 39 is closed by the movable mold 1 in the first position, the molten resin does not flow into the molding space 23 through the third resin injection gate 39. Thereby, the filling time of the molten resin into the two molding spaces 21 and 23 is made uniform,
The occurrence of unfilled locations is avoided. Similarly, also in the second position, the first resin injection gate 35 is
Molding space 53,5
5, the filling time of the molten resin is made uniform, and the occurrence of unfilled portions is avoided.

FIG. 6 shows a molding die for a hollow molded product according to another embodiment of the present invention, in which the same components as those in FIG. 1 are denoted by the same reference numerals. Also in this embodiment, the positional relationship between the movable mold 1 and the fixed mold 3 can be switched between the first position in FIG. 1 and the second position in FIG. 4, and FIG. 1 shows a first position similar to FIG. 1.

The structural difference from FIG. 1 is that on-off valves 63 and 65 capable of shutting off the flow of the molten resin are provided in the resin injection pipes 35a and 39a. However, here
In the fixed mold 3, it is assumed that auxiliary communication passages 67 and 69 communicating with the first resin injection gate 35 and the third resin injection gate 39 are formed on the surface facing the movable mold 1. . The auxiliary communication passage 69 is shown in FIG.
The auxiliary communication passage 67 communicates with the molding space 55 shown in FIG. 4 at the second position at the first position shown in FIG.

In the embodiment shown in FIG. 6, in the first position, the opening / closing valve 63 is opened and the opening / closing valve 65 is closed, thereby forming the molding space 2 from the third resin injection gate 39.
3 is prevented from being supplied with resin. Thereby, the filling time of the molten resin into the two molding spaces 21 and 23 is made uniform, and the occurrence of unfilled portions is avoided.

In the second position, the resin supply from the first resin injection gate 35 to the molding space 55 is prevented by closing the on-off valve 63 and opening the on-off valve 65, contrary to the first position. Thereby, the two molding spaces 53,
The filling time of the molten resin into 55 is made uniform.

FIG. 7 shows a molding die for a hollow molded product according to still another embodiment of the present invention. The same components as those in FIGS. 1 and 6 are denoted by the same reference numerals. Also in this embodiment, the positional relationship between the movable mold 1 and the fixed mold 3 can be switched between the first position in FIG. 1 and the second position in FIG. 4, and FIG. 1 shows a first position similar to FIG. 1.

In this embodiment, flow control valves 71 and 73 are provided in place of the on-off valves 63 and 65 in FIG. However, here, the fixed-side first concave portion 13 and the fixed-side second concave portion 15 are larger (deeper) than those in FIG.
And the movable first convex portion 9 and the movable second convex portion 1
1 is smaller than that of FIG. Therefore, the molding space 23 at the first position shown in FIG.
6 has a larger volume than the molding space 23 in FIG. 6, and similarly, although not shown, the molding space 55 in the second position also has a larger volume than that in FIG. Other configurations are the same as those in FIG.

In the embodiment of FIG. 7, in the first position, the flow control valve 71 is fully opened, and the flow control valve 73 is, for example, half-opened in accordance with the volume ratio between the molding space 21 and the molding space 23. And adjust the opening. When the molten resin is injected and injected in this state, the flow control valve 71 is fully opened.
The molten resin that flows into the first resin injection gate 35 through the mold is supplied to the molding space 21 and the groove 29,
The molten resin flowing into the second resin injection gate 37 is supplied into the molding space 23 and the groove 29, and at the same time, the molten resin flowing into the third resin injection gate 39 through the half-opened flow control valve 73. It is supplied to the molding space 23.

Here, since the molten resin is also supplied from the third resin injection gate 39 to the molding space 23 having a larger volume than the molding space 21, the opening of the flow regulating valve 73 is adjusted to a predetermined value. The filling time of the resin in the molding space 21 and the filling time of the resin in the empty molding space 23 can be made equal, thereby avoiding the occurrence of an unfilled portion.

Further, as still another embodiment, a method for equalizing the resin filling times into the molding spaces 21 and 23 having different volumes when the flow rate adjusting valves 71 and 73 are not provided in the configuration of FIG. Is described below.

When the flow control valves 71 and 73 are not provided, the molten resin injected and injected from the first resin injection gate 35 to the molding space 21 and the groove 29 and from the second resin injection gate 37 to the molding resin. In the space 23 and the groove 29, the third
Is supplied to the molding space 23 from the resin injection gate 39.

Here, in the resin injection operation, the molding space 2
When the filling time into the molding space 23 is different from the filling time into the molding space 23, the resin injection speed is increased at the time when the filling into the molding space where the filling is completed first is completed, and the remaining in the molding space where the filling is not completed is completed. To promptly supply the resin. Thereby, the overfilling amount after the filling is completed in the previously filled molding space is suppressed to half if the injection speed is doubled, for example, and the resin of the product molded in the molding space 21 and the molding space 23 is reduced. The difference in density is reduced, and quality deterioration is prevented.

FIG. 8 shows a molding die for a hollow molded product and an injection molding machine 75 according to still another embodiment of the present invention. In this molding die, a lower mold cavity 79 as a first mold is fixedly installed on a base 77, and an upper mold cavity 81 is arranged above the lower mold cavity 79 so as to be vertically movable. ing. An intermediate mold 83 is disposed between the lower mold cavity 79 and the upper mold cavity 81 so as to be able to move up and down and to be movable in a direction perpendicular to the plane of the paper of FIG.

One half body 85 (FIG. 14) constituting a hollow molded product is formed between the concave portion 79a of the lower mold cavity 79 and the convex portion 83a formed on the lower surface which is one surface of the intermediate die 83.
(See FIG. 13). On the other hand, the concave portion 81a of the upper mold 81
And a convex portion 8 formed on the upper surface which is the other surface of the intermediate mold 83.
3b, a second molding space 91 (see FIG. 13) for molding the other half body 89 (see FIG. 14) is formed.

A resin injection gate 93 for primary injection is formed in the intermediate mold 83. The primary injection resin injection gate 93 has an outlet passage 93a vertically penetrating so as to communicate the first molding space 87 and the second molding space 91, and one end on the side of the injection molding machine 75 opens outside the mold. The other end is constituted by an inlet passage 93b communicating with the outlet passage 93a. The inlet passage 93b is formed by embedding a pipe 97, and an end of the pipe 97 on the side of the injection molding machine 75 projects outside the mold.

A flow regulating valve 95 is provided at the end of the pipe 97 on the outlet passage 93a side, that is, at the connection between the outlet passage 93a and the inlet passage 93b. Flow control valve 95
The first, the molten resin flowing from the inlet passage 93b,
The degree of opening can be adjusted so that both the second molding spaces 87 and 91 can be supplied simultaneously or only to one of them. When both are supplied at the same time, the flow rates to the first and second molding spaces 87 and 91 can also be adjusted.

The injection molding machine 75 can be moved up and down by a vertical drive mechanism such as a hydraulic cylinder 99, and the injection nozzle 101 for injecting the molten resin can contact the nozzle touch portion 97a at the protruding end of the pipe 97. Thus, it can be moved in the left-right direction in FIG.

On the injection molding machine 75 side of the lower mold cavity 79, a secondary injection resin injection gate 79b for injecting a molten resin for welding a joint portion between the respective halves 85, 89 of the hollow molded product. Are formed. The resin injection gate 79b for secondary injection is formed by embedding the pipe 102, and the end of the pipe 102 on the side of the injection molding machine 75 protrudes outside the mold. This protruding end serves as a nozzle touch portion 102a with which the injection nozzle 101 of the injection molding machine 75 contacts. The end of the pipe 102 in the mold communicates with a groove 79c formed around the recess 79a via a communication path 79d.

The upper mold 8 facing the groove 79c.
A groove 81b is also formed around the first concave portion 81a, and in a state where the lower mold cavity 79 and the upper mold cavity 81 are in close contact with each other, the half bodies 85, 89 are formed by the groove 79c and the groove 81b.
An annular molding space S (see FIG. 17) to which a molten resin for secondary injection for welding the two is supplied is formed. Also, at the time of mold clamping after the primary injection (see FIG. 14), the groove 79
c, 81b so that the molten resin does not enter.
3, projections 83f, 8 fitted into the respective grooves 79c, 81b.
3 g are each formed. 1 to FIG.
6, in FIG. 20, the grooves 79c, 81b and the projections 83f,
83g is omitted.

A guide pin 83c and a guide hole 83d are formed on the upper surface of the intermediate mold 83, and a guide hole 81c and a guide pin 81d are formed in the upper mold cavity 81 in correspondence thereto. A guide pin 83e is formed on the lower surface of the intermediate mold 83, and a guide hole 79e is formed in the lower mold cavity 79 correspondingly. Further, a guide hole 79f into which the guide pin 81d of the upper-side mold 81 is inserted is formed in the lower-side mold 79.

The intermediate mold 83 is vertically movably supported by the hydraulic cylinder 103 with respect to the base 77 at a half mold forming position located between the lower mold cavity 79 and the upper mold cavity 81. , Although omitted in FIG. 8,
The drive mechanism 105 shown in FIGS. 9 and 10 can be moved between the above-described half-body molding position and the half-body welding position deviated from between the lower-side mold die 79 and the upper-side mold die 81. Has become. FIG. 9 corresponds to a view from the side of the injection molding machine 75 in FIG. 8, and FIG. 10 is a plan view of FIG.

A total of four hydraulic cylinders 103 are provided, two on each side of the intermediate mold 83, and a die receiving guide plate 1
09 is mounted. The mold receiving guide plate 109 is
It extends in the left-right direction in FIG. 10, and is provided corresponding to each of two hydraulic cylinders 103 on one side. Guide rods 111 project downward and are fixed to the lower surfaces on both sides in the longitudinal direction of the mold receiving guide plate 109. The guide rods 111 move up and down in a cylindrical rod guide 113 fixed to the base 77. It is movably housed.

A pair of roller support plates 115 are fixed to both sides of each of the mold receiving guide plates 109 in the width direction (vertical direction in FIG. 10), and a plurality of rollers 117 are provided between the pair of roller support plates 115. Are rotatably supported.
The intermediate mold 83 is placed on the roller 117. The intermediate mold 83 placed on the roller 117 is positioned and fixed at a predetermined position by a positioning and fixing mechanism (not shown).

At the lower end of the intermediate mold 85 outside the position where the rollers 117 are arranged, a rack 119 extending in the left-right direction in FIGS. 9 and 10 is mounted. Rack 1
Reference numeral 19 denotes a pinion 121 provided with a tooth portion on the lower end surface in FIG.
Are engaged. The pinion 121 is fixed to a support shaft 123 that rotatably supports the roller 117 located at the right end in FIG. 10, and the support shaft 123 is rotatably attached to the roller support plate 115. .

A sprocket 125 is further fixed to the support shaft 123. Further, the roller support plate 115
9 and FIG. 10, the connecting rod 1
27 is rotatably supported, and sprockets 129 are also attached to both ends of the connecting rod 127. further,
A drive motor 131 is mounted on the lower surface of the die receiving guide plate 109 at the left end in FIGS. 9 and 10, and a drive sprocket 133 is mounted on the drive motor 131. A chain 135 extends between the driving sprocket 133 and the two sprockets 125 and 129. That is, the driving of the drive motor 131 causes the sprocket 125 to rotate via the chain 135 and the intermediate mold 83 to which the rack 119 is attached via the pinion 121 which rotates with the sprocket 125.
It moves left and right in FIGS. 9 and 10.

The base 77 is a rightward intermediate mold 83 in FIG.
The intermediate mold receiving base 137 is installed on the extension part. Intermediate cradle 1
37, as shown in FIG.
A plurality of rollers 139 are rotatably provided on the extension of the 17 in the arrangement direction. The intermediate mold 83 is provided with the roller 11
7 is fed onto the roller 139 in a state where the roller 7 is at the same height position as the roller 139. The intermediate mold 83 sent out onto the roller 139 maintains a state in which the pinion 121 meshes with the rack 119.

FIG. 11 to FIG. 20 are operation process diagrams of the embodiment shown in FIG. FIG. 11 shows the intermediate mold 83
Is located at a position sufficiently distant from both the lower mold cavity 79 and the upper mold cavity 81, and the injection molding machine 75 is at the lowest position. This state is defined as the original position.

From the state shown in FIG. 11, the intermediate mold 83 descends to a position 20 mm before the mold clamp, and the upper mold 81 also descends to a position 20 mm before the mold clamp to enter the injection preparation state shown in FIG. Transition. At this time, the injection molding machine 75 has moved up to a position where the injection nozzle 101 faces the nozzle touch portion 97a at the end of the pipe 97 in the intermediate mold 83.

In this state, as shown in FIG. 13, the injection nozzle 101 moves forward and comes into contact with the nozzle touch portion 97a.
The molten resin is injected into the primary injection resin injection gate 93.
At this time, the flow control valve 95 is connected to the lower first molding space 87.
The opening degree is adjusted so that the molten resin is simultaneously supplied to the second molding space 91 above and the supply is completed at the same time.

Since the above-described injection operation is performed before the mold is clamped, the molten resin is injected into the first and second molding spaces 87 and 9.
1 to the end. For this reason, for example, even if an ultra-low-flow resin is used as the resin material and the thickness of the product is about 3 mm, it is possible to prevent the occurrence of the underfill at the end of the product and obtain a high-quality molded product. . Further, since the filling time of the molten resin in each of the first and second molding spaces 87 and 91 can be made equal by the flow rate adjusting valve 95, the occurrence of the underfill can be prevented.

When the injection operation of the molten resin is completed, FIG.
As shown in (2), the mold is clamped by lowering the intermediate mold 83, and the mold is clamped by lowering the upper mold 81 as well. Thereby, a pair of half bodies 8 constituting a hollow molded product
5, 89 are each formed. As described above, since the injection compression for performing the mold clamping after the injection is performed, a thinner hollow molded product can be formed, and the material cost can be reduced.

After the mold is clamped, as shown in FIG. 15, the intermediate mold 83 is moved to the roller 117 shown in FIG.
At the same time, the upper mold 37 is raised to the same height position as the roller 139 on the 37, and the upper mold 81 is also raised relative to the intermediate mold 83.

In this state, the drive motor 13 shown in FIG.
1, the intermediate mold 83 is moved backward on the intermediate mold receiving base 137 as shown in FIG. Next, each half 8
After removing the resin pieces 85a and 89a attached to the upper and lower molds 81 and 89, respectively, as shown in FIG.
Is lowered to clamp the mold with the lower mold cavity 79. At this time, the injection molding machine 75 is lowered so that the injection nozzle 101 is located at a position facing the nozzle touch section 102a.

Next, the injection nozzle 101 is advanced as shown in FIG. 18 to make contact with the nozzle touch portion 102a, and the molten resin is injected into the second injection resin injection gate 79b. As a result, the molten resin enters the annular molding space S around the joint between the half-pieces 85 and 89, and the half-pieces 85 and 89 are welded and joined to form a hollow molded article W (see FIG. 19). Is done.

Thereafter, as shown in FIG. 19, the upper mold 81 is raised to prepare for removal from the mold, and the product unloader 141 is advanced to a position below the hollow molded product W. Then, as shown in FIG. As shown in the figure, an ejector pin (not shown) provided on the upper-side mold die 81 advances (falls) and pushes the hollow molded product W onto the product unloader 141.

According to the above-described molding method, when forming the pair of half-pieces 85 and 89 constituting the hollow molded product, the first and second molding spaces 87 and 87 on the lower and upper sides, respectively. The molten resin can be simultaneously injected and supplied to 91. For this reason, the injection operation is performed in the upper and lower molding spaces 87 and 9.
Compared to the case of separately injecting the halves, the second injection operation for welding the halves together is only required twice and the molding cycle time is shortened.

In the molding operations shown in FIGS. 11 to 20, the supply of the molten resin to the first and second molding spaces 87 and 91 is simultaneously performed. It is also possible to do it separately for each side.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a molding die for a hollow molded product according to an embodiment of the present invention is at a first position.

FIG. 2 is an operation explanatory view showing a state where a molten resin is injected from the state of FIG. 1;

FIG. 3 is an operation explanatory view showing a state in which a hollow molded article and a half body are simultaneously molded from the state of FIG. 2;

FIG. 4 is a sectional view showing a state where the molding die of FIG. 1 is in a second position.

FIG. 5 is an operation explanatory diagram showing a state in which a molten resin is injected from the state of FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which a molding die of a hollow molded product according to another embodiment of the present invention is at a first position.

FIG. 7 is a cross-sectional view showing a state in which a molding die of a hollow molded product according to still another embodiment of the present invention is at a first position.

FIG. 8 is a cross-sectional view showing a molding die for a hollow molded product and an injection molding machine according to still another embodiment of the present invention.

FIG. 9 is a right side view of FIG. 8 showing details of the drive mechanism.

FIG. 10 is a plan view of FIG. 9;

FIG. 11 is an operation explanatory view showing an original position in the molding die of FIG. 8;

FIG. 12 is an operation explanatory diagram showing a primary injection preparation in the molding die of FIG. 8;

FIG. 13 is an operation explanatory view showing a primary injection operation in the molding die of FIG. 8;

FIG. 14 is an operation explanatory view showing a mold clamping operation after the primary injection in the molding die of FIG. 8;

FIG. 15 is an operation explanatory view showing preparation for retreating the intermediate mold in the molding die of FIG. 8;

FIG. 16 is an operation explanatory view showing a retreat operation of the intermediate mold in the molding die of FIG. 8;

FIG. 17 is an operation explanatory view showing a mold clamping operation before secondary injection in the molding die of FIG. 8;

18 is an operation explanatory view showing a secondary injection operation in the molding die of FIG. 8;

FIG. 19 is an operation explanatory view showing preparation for demolding in the molding die of FIG. 8;

20 is an operation explanatory view showing a demolding operation in the molding die of FIG. 8;

[Explanation of symbols]

 Reference Signs List 1 movable mold (first mold) 3 fixed mold (second mold) 5 movable-side first concave part 7 movable-side second concave part 9 movable-side first convex part 11 movable side Second convex portion 13 Fixed-side first concave portion 15 Fixed-side second concave portion 17 Fixed-side first convex portion 19 Fixed-side second convex portion 21, 23, 53, 55 Molding space 25 , 27, 41, 43 Half body 31, 33, 59, 61 Communication passage 35 First resin injection gate 37 Second resin injection gate 39 Third resin injection gate 47 Hollow molded product 63, 65 Open / close valve 67, 69 Auxiliary communication passages 71, 73 Flow control valve 79 Lower side mold (first mold) 79b Resin injection gate for secondary injection 81 Upper side mold (second mold) 83 Intermediate mold 85, 89 Half Body 87 First molding space 91 Second molding space 93 Primary injection resin injection gate G 95 Flow control valve W Hollow molded product

Claims (11)

[Claims] 1. A first mold and a second mold are provided with two first recesses and two second recesses in parallel on mutually facing surfaces of the first mold and the second mold, respectively. A first convex portion and a second convex portion are respectively provided on both sides in the parallel direction, and a first concave portion of the first mold and a first concave portion of the second mold are provided.
Are aligned with each other to form a molding space in which a half body of the hollow molded article is molded, and the second convex part of the first mold and the second concave part of the second mold are formed. The first and second mold portions are aligned with each other to form a molding space in which a half body of the hollow molded article is molded. A first position where the end faces of the respective halves, which are housed after being formed in the respective concave mold portions, are joined to each other, and the second concave portion of the first mold and the second mold The second convex portion is aligned to form a molding space in which a half body of the hollow molded product is molded, and the first convex portion of the first mold and the first convex portion of the second mold are formed. Of the first mold, while forming a molding space in which a half-piece of the hollow molded article is molded by aligning with the concave portion of the first mold.
And the second concave portion of the second mold are aligned with each other and set at the second position where the end faces of the respective halves housed after being molded in the respective concave portions are joined to each other. As possible, the first mold and the second mold are provided so as to be movable with respect to each other, and in both the first position and the second position, the mutually joined halves are connected to each other. A molding die for a hollow molded product, wherein a periphery of a joint and a molding space for molding a half body located on both sides thereof are communicated with each other through a communication passage through which molten resin injected and supplied is supplied. . 2. The method according to claim 1, wherein one of the first mold and the second mold has a first concave portion and a second concave portion between the first convex portion and the first concave portion. 2. A resin injection gate capable of injecting and injecting a molten resin toward the communication path from between the second concave portion and the second convex portion, respectively. Mold for hollow molded products. 3. The molding die for a hollow molded product according to claim 2, wherein the resin injection gate not communicating with the communication passage at each position is closed by an end surface of the other die. 4. The mold according to claim 2, further comprising an on-off valve for preventing the molten resin from flowing into the resin injection gate not communicating with the communication passage at each position. 5. A resin injection gate between the first convex portion and the first concave portion and a resin injection gate between the second concave portion and the second convex portion are provided with molten resin. A flow control valve capable of adjusting the inflow amount is provided, and among the two resin injection gates,
3. The molding of a hollow molded product according to claim 2, wherein the resin injection gate not communicating with the communication passage at each position communicates with an auxiliary communication passage communicating with a molding space adjacent to the resin injection gate. Mold. 6. A first mold and a second mold are provided with two first concave parts and two second concave parts in parallel on mutually facing surfaces of the first mold and the second mold, respectively. A first convex portion and a second convex portion are respectively provided on both sides in the parallel direction, and a first concave portion of the first mold and a first concave portion of the second mold are provided.
And the second mold portion of the first mold and the second concave portion of the second mold are aligned to form a molding space. In addition, the second concave portion of the first mold and the first concave portion of the second mold are aligned with each other, and the end face of each half body housed after being molded in each of the concave portions. At the first position where the parts are joined, a molten resin is injected and injected into each of the molding spaces to form the half-piece of the hollow molded article, and at the same time, the molten metal is melted around the joint part of the half-pieces where the end faces are joined. Resin is injected and welded to each other, and the first mold and the second mold are welded from the first position.
Relative movement of the first mold, the second mold of the first mold
And the second convex part of the second mold are aligned to form a molding space, and the first convex part of the first mold and the second convex part
The first concave portion of the first mold is aligned with the first concave portion to form a molding space, and the first concave portion of the first mold and the second concave portion of the second mold are aligned with each other. Then, the end faces of the respective halves housed after being formed in these concave portions are joined to each other.
At the same time, the molten resin is injected and injected into each of the molding spaces to form a half of a hollow molded product, and at the same time, the molten resin is injected and injected around a joint portion between the halves where the end surfaces are joined to each other. A method for forming a hollow molded product, which comprises welding halves to each other. 7. In any of the first position and the second position, when the filling of the molten resin into one molding space is completed, when the remaining filling operation of the other molding space is performed, the molten resin 7. The method for molding a hollow molded article according to claim 6, wherein the injection speed of the molding is increased from the beginning. 8. A method for molding one half of a hollow molded product in a first molding space between a first mold and one surface, and a method for molding a half mold of a hollow molded product between a second mold and the other surface. An intermediate mold for molding the other half of the hollow molded article in the second molding space of
This intermediate mold is provided with a primary injection resin injection gate capable of simultaneously supplying molten resin to the first and second molding spaces,
The intermediate mold is divided into a half mold forming position located between the first mold and the second mold, and a half body welding position at a position deviating from a position between the molds. Secondary injection for injecting a molten resin into one of the first and second dies so as to weld a joint portion between the respective halves of the hollow molded article to one of the first and second dies. A molding die for a hollow molded product, wherein a molding resin injection gate is provided. 9. The resin injection gate for primary injection is provided with a flow control valve capable of adjusting the amount of molten resin supplied to each of the first and second molding spaces. Mold for hollow molded products. 10. A first molding space between one surface of the intermediate mold and the first mold, and a second molding space between the other surface of the intermediate mold and the second mold.
The molten resin is simultaneously supplied from the primary injection resin injection gate provided in the intermediate mold to the second molding space between the molds, and a pair of halves of the hollow molded article are molded. The first and second dies are clamped in a state where the intermediate mold is moved to a position deviated from between the first and second dies. Adhere the joints of each other,
A hollow in which a molten resin is supplied from a resin injection gate for secondary injection provided in one of the first and second molds to weld and join the joint between the pair of half bodies. Molding method of molded article. 11. The first and second molds and the intermediate mold,
The mold clamping operation is performed after a molten resin is supplied from the primary injection resin injection gate to each of the first and second molding spaces at a predetermined position before the mold clamping operation. Molding method of molded article.