JP4070833B2 - Hollow molding injection molding method and injection molding die - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a fixed mold, a movable mold that is driven in the mold clamping direction and the mold opening direction with respect to the fixed mold, and a movable mold provided between the fixed mold and the movable mold. The primary molding for forming a pair of primary semi-hollow molded products with a mating mold so as to have a butt portion, and after the primary molding, the butt portions of the pair of primary semi-hollow molded products are butted together. Injection molding method of hollow molded product and injection molding used for carrying out this method, in which molten resin is injected into the part and a molded product is obtained from secondary molding in which a pair of primary semi-hollow molded products are integrated This is related to the metal mold.
[0002]
[Prior art]
A molding method using an injection molding machine is known as a method for producing a hollow molded product made of synthetic resin. The mold used for carrying out this injection molding method is roughly composed of a fixed mold and a slide mold as disclosed in, for example, Japanese Patent Application Laid-Open Nos. 6-23789 and 6-23790. It is configured. For example, one primary semi-hollow molded product of the fixed mold and the slide mold is formed on the upper parting line surface, and the other primary semi-hollow molded product is formed on the lower parting line surface. It is like that. Accordingly, in the primary molding, the slide mold is set to the first position, and a pair of primary semi-hollow molded products are molded by these molds so as to have a butt portion around the opening, and then slide after solidifying. When the mold is opened, one primary semi-hollow molded product remains on the stationary mold and the other primary semi-hollow molded product remains on the slide mold. Therefore, when the slide mold is slid to the second position, the pair of primary semi-hollow molded products come to abut at the abutting portion. Next, when the molten resin is injected into the butt portion in the secondary molding, the pair of primary semi-hollow molded products are joined at the butt portion, and the hollow molded product is molded.
[0003]
[Problems to be solved by the invention]
As described above, according to the injection molding method proposed by the present applicant, a pair of primary semi-hollow molded products molded by primary molding are abutted, and molten resin is injected and filled into the butt portion by secondary molding. As a result, a hollow molded product can be obtained, which has the advantage that each process can be automated and the hollow molded product can be mass-produced. Also, since a pair of primary semi-hollow molded products are formed by injection molding, Another feature is that a hollow molded product having a shape can be manufactured.
However, there are also points to be improved. For example, a pair of primary semi-hollow molded products are formed at the upper and lower positions or the left and right positions of the parting line surfaces of the stationary mold and the slide mold, that is, the direction of the clamping force acting. Therefore, when a large hollow molded product is to be molded, the mold becomes large and the mold clamping device there is also Toi cormorant problem to increase the size of.
Therefore, the present invention provides an injection molding method and a molding die for a hollow molded product that can make use of the above-described features of the injection molding method and can mold a large hollow molded product with a relatively small clamping force or a small mold. The purpose is to do. Another object of the present invention is to provide a hollow molded product injection molding method particularly effective for injection molding using a toggle type mold clamping device, and a molding die used for carrying out this method.
[0004]
[Means for Solving the Problems]
The above-described object of the present invention is achieved by forming a pair of primary semi-hollow molded products so as to be molded at a position in series with respect to the direction in which the clamping force acts. Alternatively, a pair of primary semi-hollow molded products are respectively molded on both sides of the middle mold, and at the time of secondary molding, the interval corresponding to the thickness of the middle mold is compensated by an adjustment liner or a hydraulic piston / cylinder device. Achieved. That is, in order to achieve the above-mentioned object, the invention according to claim 1 performs a primary molding in which a pair of primary semi-hollow molded products are molded so as to have a butt portion, and a pair of molded in the primary molding. When a primary semi-hollow molded product is abutted at the abutting portions, and a molten resin is injected into the abutted portions to obtain a hollow molded product from a secondary molding that integrates a pair of primary semi-hollow molded products. At the time of the next molding, in addition to the fixed mold and the movable mold driven in the mold clamping direction and the mold opening direction with respect to the fixed mold, the middle mold is provided between these molds so as to freely advance and retract. Using molds, these molds are clamped by a toggle mold clamping device, and a pair of primary semi-hollow molded products are molded on both side surfaces of the middle mold. The distance corresponding to the thickness of the middle mold is retracted from between the fixed mold and the movable mold. Supplemented by adjusting liner, clamping by the adjusting liner and one of the primary semi-molded article remaining the fixed die remain movable mold and the other primary semi-molded article the toggle type mold clamping device And it is comprised so that resin for secondary molding may be inject | poured into the butt | matching part of a pair of primary semi-hollow molded products, and a pair of primary semi-hollow molded products may be integrated . According to a second aspect of the present invention, in the injection molding method according to the first aspect, at the time of the secondary molding, the molding is performed such that an interval corresponding to the thickness of the middle mold is supplemented by a hydraulic piston / cylinder device. .
According to a third aspect of the present invention, there is provided a fixed mold, a movable mold that is driven in a mold clamping direction and a mold opening direction by a toggle mold clamping device with respect to the fixed mold, and the fixed mold and the movable mold. A middle mold that is movable in the axial direction between the mold and movable in a direction that advances and retreats between the fixed mold and the movable mold, and a mold thickness of the middle mold A mold comprising an interval holding member that holds an interval corresponding to the above, and a primary semi-hollow molded product that forms a pair between the fixed mold and the intermediate mold and between the intermediate mold and the movable mold When the middle mold is withdrawn from between the fixed mold and the movable mold, an interval corresponding to the thickness of the middle mold is maintained. It is comprised so that it can hold | maintain with a member. The invention according to claim 4 is the mold according to claim 3, wherein the middle mold is held movably in the axial direction between the fixed mold and the movable mold by the middle mold holding device, When the movable mold is opened from the middle mold by a predetermined amount, the middle mold is also opened from the fixed mold by a predetermined amount, and the invention according to claim 5 is the invention according to claim 3 or 4. In the described mold, the spacing member is composed of an adjustment liner or a hydraulic piston / cylinder device.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the metal mold | die concerning the 1st Embodiment of this invention and the shaping | molding method using this metal mold | die are demonstrated. FIG. 1 is a cross-sectional view showing a primary molded state, that is, a state where a pair of primary semi-hollow molded products A and B are molded. As shown in FIG. The mold concerned includes a stationary platen 1 located on the right side in the figure, a stationary die 2 attached to the stationary platen 1, a movable board 10 located on the left side in the figure, and similarly a mounting plate on the movable board 10. 11 is provided between the movable mold 12, the fixed mold 2, and the movable mold 12 attached via 11, so as to be movable forward and backward in the drawing, and also movable in the axial direction. The middle mold 20 is configured, the middle mold holding device 30 supporting the middle mold 20, the adjustment liner 50 shown at the retracted position below the movable platen 10, and the like.
[0006]
A sprue 3 facing the injection nozzle N is provided at a substantially central axis portion of the fixed plate 1 so as to cross the fixed plate 1. The sprue 3 communicates with a runner 4 formed in the fixed mold 2. The runner 4 once rises upward in the fixed mold 2 and extends in the horizontal direction, and is aligned with a runner 24 provided in the middle mold 20 described later in detail. On the surface of the fixed mold 2 facing the middle mold 20, a concave portion 5 opened in the paring line surface is formed. The outer peripheral surface of one primary semi-hollow molded product A is formed by the recess 5. Further, pins 7 and 7 ′ are provided on both sides of the fixed mold 2 as shown in FIG. In FIG. 1, only the pin 7 located on the front side is shown, and the pin 7 ′ located on the far side has a dash “′” attached to the reference numeral “7” in the specification, but simplifies the drawing. Therefore, it is not shown in the figure. In the following, similarly, a member to which a dash “′” is attached may not be shown in the drawing.
[0007]
The overall shape of the middle mold 20 has a substantially rectangular parallelepiped shape as shown in FIG. As shown in detail in FIG. 2, the inner surface of one primary semi-hollow molded product A cooperates with the concave portion 5 of the fixed mold 2 on one surface facing the fixed mold 2. A core 21a for forming the surface is formed. And the continuous groove | channel 22a for shape | molding a butt | matching part in the opening part of the primary semi-hollow molded product A around the core 21a, and the convex part 23a concentric with this groove | channel 22a are formed. On the other surface of the middle mold 20 facing the movable mold 12, the core 21b for molding the other primary semi-hollow molded product B, the continuous groove 22b, and the convex portion 23b are similarly provided. Is formed. The middle mold 20 is provided with a runner 24 for primary molding. When one of the runners 24 is clamped for primary molding, as shown in FIG. 1, the runner 24 communicates with the runner 4 of the fixed mold 2, and the other branches to the core 21 a of the middle mold 20. , 21b, respectively.
[0008]
As schematically shown in the perspective views of FIG. 1 and FIG. 3A, the middle mold holding device 30 is arranged in the vertical direction with a wider interval than the width of the middle mold 20. It comprises a pair of rod-shaped guide members 31, 31 'and a pair of mold opening members 35, 35' having a predetermined length provided outside the guide members 31, 31 'so as to cross the guide members 31, 31'. ing. The guide members 31 and 31 ′ and the mold opening members 35 and 35 ′ are integrated and supported by a device (not shown) so as to be movable in the left-right direction in FIG. The pair of guide members 31, 31 ′ are formed with guide through holes 32, 32 ′ in the axial direction, and one end is fixed to the inner mold 20 in these through holes 32, 32 ′. The guide pins 33A, 33B, 33A ′, 33B ′ are slidably inserted. The lower end of the middle mold 20 is connected to the piston rod of the hydraulic piston / cylinder device 37. Therefore, when pressure oil is supplied to or discharged from the hydraulic piston / cylinder device 37, the middle mold 20 is guided by the pair of guide members 31 and 31 'and is driven in the vertical direction, so that the fixed mold 2 and the movable mold 12 A primary molding position located between them and a secondary molding position retracted from this position can be adopted.
[0009]
Predetermined long holes 36 and 36 ′ are formed in the mold opening members 35 and 35 ′ in the axial direction. Then, pins 7 and 7 ′ whose end portions are fixed to the fixed mold 2 are inserted into the long holes 36 and 36 ′. In addition, as shown in FIG. 3B, there is a predetermined interval between the pins 7 and 7 ′ and the right end of the long holes 36 and 36 ′ in the clamped state.
[0010]
On the surface of the movable mold 12 facing the middle mold 20, a recess 15 opened to the paring line surface is formed as shown in FIG. By this recess 15, a cavity for another primary semi-hollow molded product B is formed in cooperation with the core 21 b, the continuous groove 22 b, and the protrusion 23 b of the middle mold 20. A runner 14 for secondary molding is provided on the parting line surface. Similar to the fixed mold 2, pins 17 and 17 ′ are provided on both sides of the movable mold 12. These pins 17, 17 'are also slidably inserted into the long holes 36, 36' of the mold opening members 35, 35 '. As shown in FIG. 3B, there is a predetermined distance L between the pins 17 and 17 ′ and the left end portions of the long holes 36 and 36 ′ in the clamped state. Thereby, the movable metal mold | die 12 and the middle metal mold | die 20 can be opened to the space | interval L so that it may mention later. A plurality of ejector pins 19, 19 having end portions attached to the ejector plate 18 face the bottom surface of the concave portion 15 of the movable mold 12 so as to freely advance and retract.
[0011]
The adjustment liner 50 is approximately the size of the movable platen 10 and is selected to be approximately equal to the thickness of the middle mold 20. Therefore, when the adjustment die 50 is inserted instead of the middle die 20 by retracting or removing the middle die 20, the die can be clamped and subjected to secondary molding without taking steps such as die thickness adjustment. . In order to attach the adjustment liner 50, a bracket 51 is fixed below the movable platen 10 in the illustrated embodiment. A hydraulic piston / cylinder device 54 that drives the adjustment liner 50 in the vertical direction is attached to the arm 53 of the bracket 51. The hydraulic piston / cylinder device 54 is shown briefly in FIGS. 1 and 2, but when the piston rod 55 is extended, the adjustment liner 50 fixed to the tip of the piston rod 55 is shown in FIG. It is driven from the position to the position of the movable mold 12 shown in FIG.
[0012]
Next, using these molds 2, 12, 20, adjustment liner 50, etc., a pair of primary semi-hollow molded products A and B are formed by primary molding, and melted at the butt portion of the peripheral edge of the opening A molding method for molding a hollow molded product by a secondary molding method for injecting resin will be described. A state where primary molding is possible is made. That is, the middle mold 20 is driven between the fixed mold 2 and the movable mold 12 by the hydraulic piston / cylinder device 37. Also, the adjustment liner 50 is retracted from the position aligned with the movable mold 12 to the position shown in FIG. Then, for example, the mold is clamped by a toggle type mold clamping device . Then, predetermined cavities are formed between the fixed mold 2 and the middle mold 20 and between the middle mold 20 and the movable mold 12 by the above-described recesses 5 and 15 and the cores 21a and 21b. This state is shown in FIG.
[0013]
A separately weighed molten resin is injected from the injection nozzle N. The molten resin is filled into both cavities through the runner 4 of the fixed mold 2 and the runner 24 of the middle mold 20. Accordingly, the pair of primary semi-hollow molded products A and B are molded so as to have a butt portion at the opening portion by the grooves 22a and 22b and the convex portions 23a and 23b. The movable platen 10 is driven to open the movable mold 12. When the movable platen 10 is opened, the ends of the pins 17 and 17 ′ are fixed to the movable platen 10, so that they move together with the movable platen 10 in the long holes 36 and 36 ′ in the mold opening direction. When the movable platen 10 is opened by L, the pins 17, 17 ′ reach the left end portions of the long holes 36, 36 ′. When further opened, the pins 17, 17 'now drag the mold opening members 35, 35'. Since the mold opening members 35 and 35 ′ are integrated with the guide members 31 and 31 ′, the guide members 31 and 31 ′ also move in the mold opening direction. Then, since the middle mold 20 is coupled to the guide members 31 and 31 ′ via the guide pins 33A, 33B, 33A ′ and 33B ′, the middle mold 20 is separated from the fixed mold 2 by a predetermined amount. Accordingly, the middle mold 20 is in a state where it can be separated from the movable platen 10 and the fixed mold 2 by a predetermined amount or can be retracted. At this time, the pair of primary semi-hollow molded products A and B remain in the fixed mold 2 and the movable mold 12 due to the difference in surface area, the suction action of a suction device provided separately, and the like. Since the middle mold 20 is in the detached state, the middle mold 20 is retracted to the position shown in FIG. 2 by the hydraulic piston / cylinder device 37.
[0014]
The adjustment liner 50 is driven between the movable platen 10 and the mounting plate 11 by the hydraulic piston / cylinder device 54. Then clamp the mold. Then, the movable mold 12 and the fixed mold 2 are in direct contact with each other and the butted portions of the pair of primary semi-hollow molded products A and B are butted as shown in FIG. Resin for secondary molding is injected from the injection nozzle N. Molten resin is filled into the abutting portion from the runner 4 of the fixed mold 2 through the runner 14 of the movable mold 12. Thereby, a pair of primary semi-hollow molded products A and B are integrated. The movable mold 12 is opened and the molded product is taken out by the ejector pins 19 and 19.
[0015]
As described above, according to the present embodiment, the pair of primary semi-hollow molded products A and B at the time of primary molding are molded on both sides of the middle mold 20, that is, in the direction in which the mold clamping force acts. On the other hand, since the molding is performed at the serial position, the molding can be performed with a smaller clamping force as compared with the conventional molding at the parallel position. Therefore, a large hollow molded product can be molded with a small mold. Moreover, since it shape | molds in a serial position, the area of a metal mold | die may be small.
[0016]
The present invention is not limited to the above embodiment and can be implemented in various forms. For example, in the above-described embodiment, the example in which the mold is clamped by the toggle type mold clamping machine has been described. However, it is obvious that other mold clamping apparatuses can be applied without being limited to the toggle type mold clamping machine. Applying a toggle type mold clamping machine and obtaining a hollow molded product using the middle mold 20 requires troublesome operations such as mold thickness adjustment, but the middle mold as in the present embodiment. By using the adjustment liner 50 having the same thickness as the mold 20, there is an advantage that troublesome mold thickness adjustment becomes unnecessary. Further, although the example in which the middle mold 20 and the adjustment liner 50 advance and retreat from the lower side of the movable mold 12 and the like has been described, the middle mold 20 and the adjustment liner 50 can be provided at any position such as the upper side and the side depending on the installation space. It is also clear that the pair of primary semi-hollow molded products A and B may have different sizes, shapes, and the like, and the shape of the abutting portion is not limited to the illustrated embodiment.
Furthermore, in the above embodiment, the axial movement of the middle mold 20 is performed by the mold opening members 35 and 35 ′ and the pins 7 that move in the long holes 36 and 36 ′ of the mold opening members 35 and 35 ′. 7'17 and 17 ', but it is obvious that other methods can be used.
[0017]
A second embodiment of the present invention will be described with reference to FIGS. According to the present embodiment, hydraulic piston / cylinder devices 60, 60 are applied in place of the adjustment liner 50. That is, the same members as those described with reference to FIGS. 1 to 3 are denoted by the same reference numerals and will not be described repeatedly. However, according to the present embodiment, the hydraulic piston / cylinder device is provided between the movable platen 10 and the mounting plate 11. 60, 60 are provided. FIG. 4 corresponds to FIG. 1 described above and shows the time of primary molding. In the primary molding, the hydraulic piston / cylinder devices 60 and 60 are reduced in the same manner as in the above-described embodiment. It is clear that it can be molded. At the time of secondary molding in which the middle mold 20 is removed and molded, the thickness of the middle mold 20 is maintained at the interval between the piston rods 61 and 61 of the hydraulic piston and cylinder devices 60 and 60 as shown in FIG. It will be. According to the present embodiment, there is an advantage that molding can be performed simply by supplying and discharging pressure oil to and from the hydraulic piston / cylinder devices 60 and 60.
[0018]
【The invention's effect】
As described above, according to the present invention, primary molding for molding a pair of primary semi-hollow molded products so as to have a butt portion, and a pair of primary semi-hollow molded products molded by primary molding have a butt portion. When a hollow molded product is obtained from a secondary molding in which a pair of primary semi-hollow molded products are integrated by injecting a molten resin into the butted portions and injecting a pair of primary semi-hollow molded products, In addition to the movable mold driven in the mold clamping direction and the mold opening direction with respect to the fixed mold, a middle mold provided between these molds so as to be movable back and forth is used. Since the semi-hollow molded product is configured to be molded on both side surfaces of the middle mold, that is, it is configured to mold a pair of primary semi-hollow molded products in a series position with respect to the direction of the clamping force. Therefore, the mold clamping force is 1 even though a pair of primary semi-hollow molded products are molded simultaneously. It can be molded by the mold clamping force for molding the one Tsugihan hollow molded article. Therefore, according to the present invention , an effect peculiar to the present invention that a large hollow molded product can be molded with a relatively small clamping force using a small mold can be obtained. In addition, since the molding can be performed with a small mold with a relatively small clamping force, an effect that the mold apparatus can be manufactured at a low cost can be obtained.
At this time , after the primary molding of the pair of primary semi-hollow molded products so as to have the abutting portion, the middle mold is retracted from between the fixed mold and the movable mold to correspond to the thickness of the middle mold. Since the secondary molding is performed by supplementing the interval to be adjusted with an adjustment liner or a hydraulic piston / cylinder device as a spacing holding member , operations such as mold thickness adjustment are not required during secondary molding even if a toggle type clamping device is used. Become. At this time, since only the adjustment liner or the hydraulic piston / cylinder device is applied, the production cost of the mold is not significantly increased.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a first embodiment of the present invention in a primary molding state corresponding to a view taken along line DD in FIG. FIG.
FIG. 2 is a schematic cross-sectional view similar to FIG. 1, showing the first embodiment of the present invention in a secondary molded state.
FIG. 3 is a perspective view of a main part, in which (a) is a perspective view schematically showing a state in which the middle mold holding device and the middle mold are held, and (b) is a stationary mold, It is a perspective view which shows typically related structures, such as a metal mold | die, a movable metal mold | die, and a mold opening member.
FIG. 4 shows the second embodiment of the present invention in the same manner as in FIG. 1, corresponding to the view seen in the direction of arrows DD in FIG. It is a typical sectional view shown in a state.
FIG. 5 is a schematic cross-sectional view similar to FIG. 4 showing a second embodiment of the present invention in a secondary molded state.
[Explanation of symbols]
2 fixed mold 12 movable mold 20 middle mold 30 middle mold holding device 50 adjusting liner 60 hydraulic piston / cylinder device

Claims (5)

A primary molding for forming a pair of primary semi-hollow molded products (A, B) to have a butt portion, and a pair of primary semi-hollow molded products (A, B) molded by the primary molding. When a hollow molded product is obtained from secondary molding in which a pair of primary semi-hollow molded products are integrated by injecting a molten resin into the butted parts,
At the time of primary molding, in addition to the fixed mold (2) and the movable mold (12) driven in the mold clamping direction and the mold opening direction with respect to the fixed mold (2), these molds ( 2, 12) is used so that it can freely move forward and backward , and these molds (2, 12, 20) are clamped by a toggle type clamping device to form a pair of primary Semi-hollow molded products (A, B) are molded on both sides of the middle mold (20),
During the secondary molding, the middle mold (20) is retracted from between the fixed mold (2) and the movable mold (12), and an interval corresponding to the thickness of the middle mold (20) is adjusted. The movable mold (12) in which the adjustment liner (50) and one primary semi-molded product (B) remain, and the other primary semi-molded product (A) remain , supplemented by the liner (50). The fixed mold (2) is clamped by the toggle type mold clamping device , and a resin for secondary molding is injected into the abutting portion of the pair of primary semi-hollow molded products (A, B) to form a pair of primary semi hollow molded article (a, B) to integrate the injection molding method of a hollow molded article, characterized in that.   2. The injection molding method according to claim 1, wherein during secondary molding, a hollow piston is formed by compensating the interval corresponding to the thickness of the middle mold (20) with a hydraulic piston / cylinder device (60, 60). Method. A fixed mold (2), a movable mold (12) driven in a mold clamping direction and a mold opening direction by a toggle type mold clamping device with respect to the fixed mold (2), and the fixed mold (2 ) And the movable mold (12) are movable in the axial direction, and are also movable in the advancing and retracting direction between the fixed mold (2) and the movable mold (12). A mold comprising an intermediate mold (20) and an interval holding member that holds an interval corresponding to the mold thickness of the intermediate mold (20),
A primary semi-hollow molded product (A, B) is formed between the fixed die (2) and the middle die (20) and between the middle die (20) and the movable die (12). The cavity to be formed is formed,
When the intermediate mold (20) is retracted from between the fixed mold (2) and the movable mold (12), an interval corresponding to the thickness of the intermediate mold (20) is the interval. A mold for injection molding of a hollow molded product, which can be held by a holding member.   4. The mold according to claim 3, wherein the middle mold (20) is movable in the axial direction between the fixed mold (2) and the movable mold (12) by the middle mold holding device (30). When the movable mold (12) is held and a predetermined amount is opened from the middle mold (20), the middle mold (20) is also opened from the fixed mold (2) by a predetermined amount. Injection mold.   The mold for injection molding of a hollow molded product according to claim 3 or 4, wherein the spacing member is an adjustment liner (50) or a hydraulic piston / cylinder device (60, 60).

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