KR20030020562A - Die for injection molding - Google Patents

Abstract

PURPOSE: A metal mold of an injection molding is provided to withdraw correct specification of the injection molding by a three stage withdrawing structure for the mold. CONSTITUTION: A metal mold of an injection molding includes an upper moving die(100); a lower fixing die(200); an upper fixing core(110); a lower fixing core(210); a slider core(400); a support core(600); a slider(700); a taper pin(900); a core pin(800); a first traction pin(710) and a second traction pin(410). The upper moving die and the lower fixing die are arranged up and down. The upper fixing core and the lower fixing core are installed to the upper moving die and the lower fixing die respectively to form a first cavity(300). The slider core has a first fitting hole(330) and a second cavity(310) inside. The support core is included between the slider core and the upper moving die. The slider is installed to an outer surface of the support core to be moved back and forth. The taper pin penetrates the slider. The core pin is installed from the slider to the second cavity. The first traction pin connects the slider to the slider core. The second traction pin connects the slider core to the support core. Thereby, deformation of an undercut and a pipe is prevented by supporting around the pipe with the lower fixing core and the support core. The undercut is formed around the pipe by a three stage withdrawing structure.

Description

Injection Molding Dies {DIE FOR INJECTION MOLDING}

The present invention relates to an injection molding die, and more particularly, to an injection molding capable of injection molding a molded article integrally formed on one side of a pipe including an undercut so as to prevent the hoses from being connected to one side without deformation.

In general, the injection molding mold is manufactured in various forms according to the shape of the product to be manufactured. Meanwhile, an automotive heat exchanger such as a radiator includes a pair of header tanks having a core in which a plurality of tubes and heat transfer fins are alternately stacked, a header respectively installed at upper and lower ends of the core, and a tank installed at each of the headers. . Among these, in recent years, a case of manufacturing a radiator by injection molding a tank with resin is increasing, and therefore, a mold capable of injection molding a resin tank of a radiator to a precise specification without defect is required.

As illustrated in FIG. 7, in the case of a member such as the resin tank 10 of the radiator, a pipe 14 that may connect hoses to one side of the outer circumferential surface of the tank body 12 for inflow or discharge of cooling water is integrally formed. At the tip of the pipe 14, an annular undercut 16 protrudes to a diameter larger than the diameter of the pipe 14 in order to prevent separation of the hoses.

8 shows an example of a conventional mold for injection molding a member such as a radiator resin tank 10. The mold has an upper movable die 20 and a lower fixed die 30, and the upper movable die 20 and the lower fixed die 30 have a first cavity 40 for molding the tank body 12. The upper fixing core 21 and the lower fixing core 31 to be formed are sequentially installed. On one side of the cores 21 and 31, a second cavity 42 and the second cavity 42 communicating with the first cavity 40 to integrally form the pipe 14 together with the tank body 12. Slider core 50 forming the insertion hole 46 through the () is provided. A slider 70 is installed outside the slider core 50. The end of the second cavity 42 (ie, between the second cavity 42 and the insertion hole 46) is formed of an undercut cavity 44 having a diameter larger than the diameter of the second cavity 42. One end of the core pin 80 is embedded and fixed to a portion corresponding to the insertion hole 46 of the slider 70, and the other end of the core pin 80 is inserted through the insertion hole 46 and the second cavity 42. It is retractably inserted into the first cavity 40. In addition, the slider 70 is formed with a two-stage insertion hole 72 formed in two stages, the traction pin 72 is inserted into the two-stage insertion hole 72 so as to be movable, the end of which is the slider core 50. Is fixed to. In addition, an inclined hole 76 is formed in the slider 70, and the inclined pin 90 is inserted into the slider 70 so as to be movable across the upper movable die 20 and the lower fixing die 30. Reference numeral 32 is an eject pin for ejecting the molding.

The injection molding method of the resin tank 10 of the radiator for automobiles using the conventional injection molding mold configured as described above is performed by the following process. First, the molten resin is injected into the cavities 40, 42, and 44 through the injection hole 32 in the state shown in FIG. 8. As shown in FIG. 9, when the injected molten resin is cured, the tank body 12 is formed by the first cavity 40, and the undercut is formed by the space between the second cavity 42 and the core pin 80. It is possible to obtain a resin tank 10 in which a pipe 14 having 16 is formed integrally with the tank body 12. When the inclined pin 90 rises vertically after curing of the resin tank 10, the slider 70 is retracted by the inclined surface of the inclined pin 90 so that the core pin 80 is separated from the inside of the pipe 14. When the slider 70 is retracted by a predetermined distance, the slider core 50 is retracted by the traction pin 72 so that the slider core 50 is separated from the outer circumferential surface of the pipe 14. In this state, when the upper movable die 20 is completely removed, the resin tank 10 may be taken out by the advancement of the eject pin 32.

The injection molding mold as described above has the following problems. That is, as shown in FIG. 10, since the diameter UD of the undercut 16 is larger than the diameter PD of the pipe 14, the undercut 16 is retracted when the slider core 50 is retracted. Hanging on the inner circumferential surface of the pipe 14 is deformed. When the pipe 14 is deformed in this manner, as shown in FIG. 11, the regions E and F of the pipe 14 are smaller than the specification, and the regions G and H are larger than the specification. Therefore, the cross section of the pipe 14 does not form a round shape but is crushed in an elliptical shape. In addition, when the slider core 50 is retracted, the area A of FIG. 12 is supported by the lower fixing core 31, but the area B of the slider core 50 is not supported, and thus, the pipe 14 receives a bending load and thus the pipe (C) of FIG. 14) Cracking may occur. In addition, when the slider core 50 is retracted, as shown in FIG. 14, since the pipe 14 is subjected to a tensile force by the undercut 16, stress may be concentrated in the portion D of FIG. 13 to generate a corner crack. . In addition, a phenomenon in which the pipe 14 side portion of the tank body 12 is deformed or conducted to a space caused by the retraction of the slider core 50 may occur due to the complex load of the bending load and the tensile force. Therefore, productivity decreases due to an increase in the defective rate of the molded product and an increase in the number of production operations such as a total inspection of the molded product.

In addition to the above-described conventional examples, various injection molding dies have been proposed, but most of them have the same problems as the two-stage ejection structure as described above.

The present invention has been made in consideration of the above-mentioned conventional problems, and the injection molded product is formed without any deformation by applying a three-stage blowout structure to a pipe including an undercut integrally formed on one side so that the hoses to be connected are not pulled out. An object of the present invention is to provide injection molding.

1 is a schematic cross-sectional view showing a mold for injection molding according to the present invention.

2 is an enlarged view illustrating main parts of FIG. 1.

3 is a sectional view showing the principal parts of a one-step process for taking out a molded article formed by a mold according to the present invention.

Figure 4 is a cross-sectional view of the main part showing a two-step process for taking out a molded article formed by a mold according to the present invention.

5 is a sectional view showing the principal parts showing a three-step process for taking out a molded article formed by a mold according to the present invention.

FIG. 6 is an explanatory diagram showing a support state of a molding in the process of FIG. 4.

7 is a perspective view showing an example of a resin tank of an automobile radiator as an example of a molded product.

8 is a schematic cross-sectional view showing a conventional injection mold.

FIG. 9 is a schematic cross-sectional view illustrating a process of molding a molding by the mold of FIG. 8.

FIG. 10 is an enlarged view of a portion of the pipe with an undercut in the molding of FIG. 9.

It is explanatory drawing which shows the deformation | transformation part of the molded object shape | molded and taken out by the metal mold | die of FIG.

FIG. 12 is an explanatory view showing a support state of a molded product in the process of taking out the molded product formed by the mold of FIG. 8; FIG.

It is explanatory drawing which shows the defect part of the molded object shape | molded and taken out by the metal mold | die of FIG.

It is explanatory drawing which shows the example of the defect which arises in the process of taking out the molded object shape | molded by the metal mold | die of FIG.

<Explanation of symbols for the main parts of the drawings>

10: resin tank, 12: tank body,

14: pipe, 16: undercut,

100: upper movable die, 110: upper fixing core,

200: lower fixing die, 210: lower fixing core,

300: the first cavity, 310: the second cavity,

320: undercut cavity, 330: the first insertion hole,

400: slider core, 410: second towing pin,

412, 712: stopper, 420: third insertion hole,

600: support core, 700: slider,

710: the first towing pin, 720: the second insertion hole,

730: inclined hole, 800: core pin,

900: inclined pin

In order to achieve the above object, the injection molding mold according to the present invention, the upper movable die and the lower fixing die; An upper fixing core and a lower fixing core which are sequentially installed to form a first cavity for forming a main body in the upper movable die and the lower fixing die; Slider core which is installed on one side of the upper and lower fixing cores to form a pipe having an undercut integrally with the main body to form a second cavity communicating with the first cavity and a first insertion hole connected to the second cavity therein Wow; A support core interposed between the slider core and the upper movable die; A slider installed on the outside of the slider core and the support core so as to be retracted and having an inclined hole formed at one side thereof; An inclined pin installed to be movable over the upper movable die and the lower fixed die through the inclined hole; A core pin having one end fixed to the slider and a free end being retractably inserted into the second cavity through the first insertion hole and having a diameter corresponding to the second cavity smaller than an inner diameter of the second cavity; A first towing pin, one end of which is supported by the slider to be retractable and the other end of which is fixed to the slider core; In addition, one end of the slider core is supported to be retractable and the other end includes a second towing pin fixed to the support core.

The end of the second cavity (ie, between the second cavity and the first insertion hole) is formed of an undercut cavity having an inner diameter larger than that of the second cavity.

The first towing pin and the second towing pin, each stopper having a diameter larger than the other portion is inserted into the large diameter portion of the two-stage insertion hole respectively formed in the slider and the slider core, each end is retractable By being fixed to the slider core and the support core in turn through the small diameter portion of each two-stage insertion hole, the slider and the slider core can be supported in advance.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are defined in the technical spirit of the present invention on the basis of the principle that the inventor can appropriately define the concept of the term in order to explain his invention in the best way. It must be interpreted to mean meanings and concepts. In addition, in the present invention, an injection molding die for molding a resin tank constituting a radiator for automobiles will be described as an example.

As shown in FIG. 1, the injection molding die according to the present invention includes an upper movable die 100 and a lower fixing die 200 disposed above and below, and a first cavity 300 to form the first cavity 300. 100 and the lower fixing die 200, the upper fixing core 110 and the lower fixing core 210 are installed in sequence, and the second cavity 310 and the first insertion hole 330 to form a slider core ( 400, a support core 600 interposed between the slider core 400 and the upper movable die 100, and a slider removably installed outside the slider core 400 and the support core 600. 700, an inclined pin 900 movably penetrating through the slider 700, a core pin 800 installed over the slider 700 and the second cavity 310, and the slider 700. And a first towing pin 710 connecting the slider core 400 to the slider core 400 and the slider core 400 and the support core 600. It comprises a second towing pin 410.

An upper portion of the first cavity 300 may be formed by the upper fixing core 110, and a lower portion thereof may be formed by the lower fixing core 210. The first cavity 300 is formed in a space having the same size as that of the tank body 12 of the resin tank 10 constituting the automobile radiator as shown in FIG. 7. An injection hole (not shown) for injecting molten resin into the first cavity 300 is installed in the lower fixing die 200, and the lower fixing die 200 is separated from the molded resin tank 10. Eject pin 220 is installed.

Concave grooves are formed in the inner surface of the slider core 400 and the outer surface of the core pin 800, respectively, and the concave grooves are combined to form a second cavity 310 and a first insertion hole 330. The second cavity 310 communicates with the first cavity 300 so that the pipe 14 of the resin tank 10 can be integrally formed with the tank body 12. The second cavity 310 also communicates with the first insertion hole 330, and the end of the second cavity 310 (ie, between the second cavity 310 and the first insertion hole 330) is a pipe that is formed. (14) An undercut cavity 320 (see FIG. 2) having an inner diameter larger than the inner diameter of the second cavity 310 so that the undercut 16 can be formed at the tip.

The slider core 400 is formed such that its inner end forming the second cavity 310 has a thickness that is significantly thinner than the outer end forming the first insertion hole 330, so that the outer end has a larger thickness than the inner end. The support core 600 is installed to have a high height and cover the outside of the slider core 400. Accordingly, the outer end inner surface of the slider core 400 is in contact with the inner end outer surface of the support core 600.

The support core 600 is installed so that the slider core 400 can be moved forward and backward while the slider core 400 is moved forward and backward. The support core 600 will be described later.

On the other hand, the slider 700 that is removably installed on the outer side of the slider core 400 and the support core 600, the height of the inner end is the same height as the height of all the heights of the cores (400, 600) The outer end is tapered downward and then extends outward. Inclined holes 730 are formed in the outer end of the slider 700 up and down, and through the inclined holes 730, the inclined pins movably across the upper movable die 100 and the lower fixed die 200. 900 is installed. Therefore, when the inclined pin 900 moves vertically upward, the slider 700 retreats backward by the inclined surface of the inclined pin 900, and when the inclined pin 900 moves vertically downward, the slider 700 moves to the cores ( 400, 600).

In addition, one end of the core pin 800 is embedded in the surface corresponding to the first insertion hole 330 of the slider 700, and the free end of the core pin 800 is fixed through the first insertion hole 330. It is retractably inserted into the second cavity 310. Therefore, when the slider 700 moves forward and backward, the core pin 800 may also move forward and backward. The free end of the core pin 800, that is, the diameter of the portion corresponding to the second cavity 310 of the core pin 800 is smaller than the inner diameter of the second cavity 310, and thus, the second cavity 310 and the core The space between the pins 800 functions as a space for forming the pipe 14 with the undercut 16.

On the other hand, as shown in Figure 2, the slider 700 has a second insertion hole 720 of the two-stage insertion hole structure having a large diameter portion and a small diameter portion of the outer side is formed horizontally, this second insertion hole The first towing pins 710 are inserted into and retractable through the 720. A stopper 712 is formed at the outer end of the first towing pin 710 so as to be retractable from the large diameter portion of the second insertion hole 720 so as not to be separated toward the small diameter portion of the second insertion hole 720. . In addition, the inner end of the first towing pin 710 is fixed to the slider core 400 through the small diameter portion. Accordingly, when the slider 700 is retracted, the stopper 712 of the first towing pin 710 is caught by the jaw, which is a boundary between the large diameter portion and the small diameter portion of the second insertion hole 720, and the slider 700 is in this state. If further retracted, the slider core 400 may be retracted by the first towing pin 710.

In addition, as shown in Figure 2, the outer end of the slider core 400, the third insertion hole 420 of the two-stage insertion hole structure having an outer large diameter portion and the inner small diameter portion is formed horizontally The second towing pin 410 is inserted through the third insertion hole 420 to be retractable. A stopper 412 is formed at the outer end of the second towing pin 410 so as to be retractable from the large diameter portion of the third insertion hole 420 so as not to be separated toward the small diameter portion of the third insertion hole 420. . In addition, the inner end of the second towing pin 410 is fixed to the inner end of the support core 600 in contact with the slider core 400 through the small diameter portion. Therefore, when the slider core 400 is retracted, the stopper of the second towing pin 410 is caught by the jaw, which is the boundary between the large diameter portion and the small diameter portion of the third insertion hole 420, and in this state, the slider core 400 is further caught. When retracting, the support core 600 may be retracted by the second towing pin 410.

Next, a process of molding the resin tank 10 of the automobile radiator as shown in FIG. 7 and taking out the molded resin tank 10 by the injection molding mold according to the present invention configured as described above will be described.

First, by injecting the molten resin into the first cavity 300 and the second cavity 310 through the inlet not shown in the injection molding mold according to the present invention as shown in Figure 1 by curing the injected molten resin The resin tank 10 is molded. That is, the tank body 12 of the resin tank 10 is formed by the first cavity 300 and undercut integrally with the tank body 12 by the space between the second cavity 310 and the core pin 800. A pipe 14 with 16 is formed. In order to take out the resin tank 10 formed in this way from a metal mold | die, the inclined pin 900 is first raised upwardly. As the slider 700 is pushed by the inclined surface of the inclined pin 900 in accordance with the vertical rise of the inclined pin 900, the free end of the core pin 800 starts to be separated from the inside of the pipe 14. .

When the slider 700 is further retracted as shown in FIG. 4, the core pin 800 is completely removed from the pipe 14 and placed in the first insertion hole 330, and the stopper of the first towing pin 710 is removed. The slider core 400 begins to retreat because the 712 is caught by the jaw, which is a boundary between the large diameter portion and the small diameter portion of the second insertion hole 720. At this time, since the inner diameter of the second cavity 310 of the slider core 400 is smaller than the outer diameter of the undercut 16, the upper end of the undercut 16 of the pipe 14 is deformed inward when the slider core 400 is retracted, but the undercut 16 6 is supported by the support core 600 supporting the Q region of FIG. 6, and the O region and the P region of FIG. 6 are supported by the lower fixing core 210. Therefore, all areas outside the resin tank 10 are uniformly supported. Therefore, the bending load or tensile force acting on the pipe 14 is minimized so that the deformation element is removed, thereby minimizing the deformation of the pipe 14. That is, as shown in FIG. 6, since only the region corresponding to the distance from which the slider core 400 is retracted out of the R region, which is the thickness region of the inner end of the slider 700, is removed from the support region, the slider core 400 is retracted. The deformation of the pipe 14 may be minimized, and thus, the pipe 14 crack or the corner crack phenomenon as shown in FIG. 13 does not occur in the process of taking out the resin tank 10.

When the slider core 400 is further retracted as shown in FIG. 5 so that the slider core 400 is completely separated from the pipe 14, the upper end of the deformed undercut 16 when the slider core 400 is retracted may be caused by elastic force. The support core 600 starts to retreat because it is restored to the original specification and the stopper 412 of the second towing pin 410 is caught in the jaw, which is a boundary between the large diameter portion and the small diameter portion of the third insertion hole 420. . After the support core 600 completely exits the area corresponding to the pipe 14, the resin tank 10 is taken out by moving the eject pin 32 in a state where the upper movable die 100 is separated.

In the injection molding die according to the present invention configured as described above, in the process of taking out the molded product having the undercut 16, the lower fixing core (circumferentially fixed portion of the pipe 14 on which the undercut 16 is formed by the three-stage ejection structure) 210 and the support core 600 to prevent deformation of the pipe 14 and deformation of the undercut 16, it is possible to increase the productivity by reducing the defective rate of the molding, to produce a molding having a stable specification This can increase the reliability of the molded product.

Claims (3)

An upper movable die and a lower fixed die; An upper fixing core and a lower fixing core which are sequentially installed to form a first cavity for forming a main body in the upper movable die and the lower fixing die; Slider core which is installed on one side of the upper and lower fixing cores to form a pipe having an undercut integrally with the main body to form a second cavity communicating with the first cavity and a first insertion hole connected to the second cavity therein Wow; A support core interposed between the slider core and the upper movable die; A slider installed on the outside of the slider core and the support core so as to be retracted and having an inclined hole formed at one side thereof; An inclined pin installed to be movable over the upper movable die and the lower fixed die through the inclined hole; A core pin having one end fixed to the slider, the free end being retractably inserted into the first cavity through the first insertion hole and the second cavity, and having a diameter corresponding to the second cavity smaller than an inner diameter of the second cavity; A first towing pin, one end of which is supported by the slider to be retractable and the other end of which is fixed to the slider core; And, An injection molding mold, characterized in that the slider core includes a second towing pin fixedly supported on the support core and the other end fixed to the support core. The method of claim 1, The portion between the second cavity and the first insertion hole is formed of an undercut cavity having an inner diameter larger than the inner diameter of the second cavity. The method according to claim 1 or 2, The first towing pin and the second towing pin, each stopper having a diameter larger than the other portion is inserted into the large diameter portion of the two-stage insertion hole respectively formed in the slider and the slider core, each end is retractable An injection molding die, which is supported by a slider core and a support core in order to be retractable in order by being fixed to a slider core and a support core in turn through a small diameter portion of each two-stage insertion hole.