JP7209414B1 - Injection mold and injection molding method - Google Patents

Abstract

SOLUTION: Two second inner slide cores (30) are arranged on the remaining two inner sides of the frame (F), which are different from the two sides formed by the first inner slide core (20). Form from two directions inside. The second inner rail portion 31 is provided at both ends in a direction perpendicular to the sliding direction of the second inner product surface forming portion so that the first inner rail portion 21 does not come into contact with the first inner rail portion 21 when the first inner rail portion 21 slides inward. It is provided closer to the center side from each of the parts. The first inner rail portions 21 are provided so as to move toward the center from both end portions of the first inner product surface forming portion in the direction perpendicular to the sliding direction. The four tilting rods 41 are capable of moving the four tilting blocks 40 along the direction tilting from the opening/closing direction of the mold 1, and after the mold 1 is opened, the four tilting rods 41 are arranged in the four tilted directions of the frame F. The block 40 is pushed out and separated from the square inner surface of the frame F. The four movement-preventing pins 50 have tip portions 50a forming part of the tip portions Ua of the undercut portions U on the four sides of the frame F, and as the four inclined blocks 40 move, the undercut portions U of the frame F are formed. The mold 1 is moved along the opening/closing direction while holding a part of the front end portion Ua of the mold 1 . [Selection drawing] Fig. 3

Description

The present invention relates to an injection mold and an injection molding method.

Conventionally, a door based on a frame body such as a refrigerator door using glass is composed of an outer plate and an inner plate, and a heat insulating material interposed between them, and is an example of a resin molded product. The outer plate of the refrigerator door is manufactured by injection molding. A side plate is provided on the outer edge of the flat plate of the outer plate, and an inward piece (hereinafter referred to as a rib) extends from the outer end of the side plate so as to be substantially parallel to the flat plate. . After installing a glass plate on the plane plate of the outer plate, a heat insulating material is injected between the glass plate and the ribs of the outer plate, and the inner plate is set and integrated.

Here, when the outer plate is integrally formed, the ribs of the outer plate must be formed along the entire inner circumference of the plane plate. However, in the injection mold used to manufacture resin molded products, these ribs act as undercuts, and the undercuts are required along the entire inner circumference of the outer panel. complicated.

Therefore, in order to facilitate manufacturing, multiple parts were manufactured separately by dividing the outer panel, and the ends of the multiple parts were joined later to manufacture an integrated outer panel. .

However, adopting such a configuration and procedure increases the number of parts, multiple manufacturing and joining steps, and increases overall manufacturing costs. In addition, since the joint portion is exposed to the outside, there is a problem in terms of appearance. Furthermore, when some external force is applied to the outer plate, the entire outer plate is easily damaged due to the detachment of the joint portion. In other words, there were various problems.

Therefore, in Japanese Patent Application Laid-Open No. 2000-94479 (Patent Document 1), a side plate is erected along the outer edge of a polygonal plane plate, and the outer end of the side plate is substantially parallel to the plane plate. An injection mold is disclosed for manufacturing a resin molded article having ribs extending therefrom. In this injection molding die, the stationary side die facing the moving side die with the molding space interposed therebetween is provided at each position corresponding to each corner of the plane plate, and is arranged inwardly. and corner moving blocks that move inward, and side moving blocks that are disposed at respective positions corresponding to the sides of the plane plate and move inward. As a result, a two-stage operation is possible in which the corner moving block is first moved inward after the mold is opened, and then the side moving block is moved inward. It states that undercut processing can be performed without any inconvenience even for a resin molded product having ribs extending around the periphery.

Further, Japanese Patent Application Laid-Open No. 2011-31589 (Patent Document 2) discloses an injection molding die for manufacturing a molded product having an annular undercut in the shape of an inward groove. A movable mold for this injection mold includes a movable mounting plate, a spacer block fixed to the mating surface side of the movable mounting plate, and a receiving plate fixed to the mating surface side of the spacer block. The movable mold includes a center core fixed to the central portion of the receiving plate on the mating surface side, a movable mold plate supported on the outer peripheral portion of the mating surface side of the receiving plate so as to be able to move forward and backward, and an outer side of the center core. a plurality of first slide cores and second slide cores alternately arranged along an outer side thereof to enclose the . In the movable mold, the first slide core and the second slide core are fitted into the accommodation space between the center core and the movable mold plate, and are fitted into a portion corresponding to the inner side of the undercut. The movable mold includes opening means for applying an opening force to widen the space between the movable-side mounting plate and the receiving plate, and stop bolts for regulating the widening of the space between the movable-side mold plate and the receiving plate. Prepare. After the molded product is cured, the movable mold relatively retreats the center core by the opening means, and then sequentially moves the first slide core and the second slide core inward. The opening means applies an opening force in the first half stage of mold opening. In order to move the first slide core by the inner slide core method in the second half stage of mold opening, the first slide core has an underside. It has an engaging portion that protrudes outward from the cut. One of the stationary mold and the engaging portion of the first slide core is provided with an angular pin, and the other is provided with a fitting hole through which the angular pin enters and exits. As a result, the center core retreats relatively to the first and second slide cores and the like in the first half of mold opening by applying the opening force by the opening means, and the first slide core moves inward. A movement space for movement is formed. Since the first slide core is moved inward by the inner slide core method in the latter half of mold opening, only the second slide core needs to be moved after mold opening. Therefore, the process required for undercut treatment after opening the mold is only one process of moving the second slide core, and the molding cycle can be shortened.

JP-A-2000-94479 Japanese Unexamined Patent Application Publication No. 2011-31589

As described above, the frame-based door includes, for example, the four frame parts of the door, a top cap, a bottom cap, and two side caps, a glass plate, a vacuum-formed inner door, and a gasket packing. After assembling the parts and joining the ends of the four frame parts, a heat-insulating urethane is injected into the gaps between the parts. As described above, this manufacturing method has problems such as an increase in the number of parts, an increase in the number of joining processes, poor appearance, and weak overall strength. There is a problem that On the other hand, there was a certain degree of difficulty in manufacturing a mold for integrally molding a square frame having an undercut shape on the entire periphery.

Here, in the technique described in Patent Document 1, after the mold is opened, the corner portion moving block is moved inward, and then the side portion moving block is moved inward. There is a problem that a step-by-step process is required and it takes time.

Further, in the technique described in Patent Document 2, the center core is retracted by the opening means in the first half stage of mold opening, and the first slide core is moved inward in the second half stage of mold opening. Installation is necessary, the structure of the mold becomes complicated, and the existence of the opening means makes the whole mold large. Therefore, there is a demand for an injection mold that can reduce the number of processes and reduce the size of the entire mold in the production of a molded product of an outer plate (frame body) provided with an inwardly grooved undercut. had been

Therefore, the present invention has been made to solve the above problems, and an injection molding die and an injection molding method capable of efficiently manufacturing a frame having undercut portions on the inner surfaces of each of the four sides. intended to provide

An injection mold according to the present invention is an injection mold for molding a frame provided with curved undercuts on the inner surfaces of each of the four sides, and comprises four outer slide cores and an outer rail. two first inner slide cores; a first inner rail section; two second inner slide cores; a second inner rail section; four tilt blocks; four tilt rods; and an anti-migration pin. The four outer slide cores form the outer surfaces of the four sides of the frame from the four directions outside the frame. The outer rail portion is provided on the outer slide core, and allows the outer slide core to slide outward by an angular pin. The two first inner slide cores are provided with respective first inner product surface forming portions, of the inner surfaces of the four sides of the frame including the inner surface of the undercut portion, the inner surfaces of the two opposing sides of the frame. Form from two directions inside the body. The first inner rail portion is provided by a predetermined first distance from each of both ends of the first inner product surface forming portion of the first inner slide core in a direction perpendicular to the sliding direction toward the center. An inner slide core is made slidable inward by an angular pin. The two second inner slide cores are formed by their respective second inner product surface forming portions on the remaining two sides, which are different from the two sides formed by the first inner slide core, among the inner surfaces of the four sides of the frame. Side surfaces are formed from two directions inside the frame. The second inner rail portion slides in the sliding direction of the second inner product surface forming portion of the second inner slide core so that the first inner rail portion does not contact when the first inner rail portion slides inward. The second inner slide core is provided to the center side by a predetermined second distance from each of both ends in the direction perpendicular to the second inner slide core, and the second inner slide core can be slid inward by the angular pin. The four inclined blocks form the square inner surface of the frame from the four directions inside the frame, and are provided so as to fit the first inner slide core and the second inner slide core respectively. . The four tilting rods are connected to the four tilting blocks, and are capable of moving the four tilting blocks along the direction tilting from the opening/closing direction of the mold, and the frame body after the mold is opened. The four slanted blocks are pushed out to the four squares and separated from the square inner surface of the frame. At least four anti-movement pins have tips forming the tips of the undercuts on the four sides of the frame, and hold the tips of the undercuts of the frame as the four inclined blocks move. , move along the opening/closing direction of the mold, and prevent the frame from moving relative to the direction perpendicular to the opening/closing direction of the mold.

An injection molding method for an injection mold according to the present invention includes a slide core step and an inclined block step. In the slide core step, when the main mold is opened, the outer slide core is slid outward by the angular pin, the first inner slide core is slid inward by the angular pin, and the second The two inner slide cores are slid inward by the angular pin. In the tilt block step, the four tilt blocks are moved along a direction tilted from the opening and closing direction of the main mold to separate from the square inner surface of the frame, and the movement prevention pin is moved to the frame. While holding part of the tip of the undercut portion, it is moved along the opening and closing direction of the mold.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture efficiently the frame which has an undercut part in each inner surface of four sides.

It is the perspective view of the frame which concerns on embodiment of this invention, the perspective view of an injection-molding metal mold, and a top view. FIG. 4A is a perspective view of a first inner slide core and a second inner slide core according to an embodiment of the present invention, and a perspective view showing the inward sliding of the first inner slide core and the second inner slide core; It is a sectional view showing movement of an inclination block concerning an embodiment of the present invention. 1A and 1B are a plan view and a perspective view showing before and after mold opening of an injection molding die according to an embodiment of the present invention; FIG. FIG. 4A is a plan view showing sliding of an outer slide core, a first inner slide core, and a second inner slide core, and a cross-sectional view showing the outer slide core and the first inner slide core according to the embodiment of the present invention; FIG. 2 is a plan view showing sliding of an outer slide core, a first inner slide core, and a second inner slide core according to an embodiment of the present invention; and a perspective view. It is the top view and perspective view which show the movement of the inclination block and the movement prevention pin which concern on embodiment of this invention. It is the perspective view and sectional view which show completion of movement of the inclination block and the movement prevention pin which concern on embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. It should be noted that the following embodiment is an example that embodies the present invention, and is not intended to limit the technical scope of the present invention.

As shown in FIG. 1, an injection mold 1 according to an embodiment of the present invention is an injection mold for molding a frame F provided with undercut portions U curved on the inner surfaces of each of the four sides. 1, four outer slide cores 10, an outer rail portion 11, two first inner slide cores 20, a first inner rail portion 21, two second inner slide cores 30, a second inner It comprises a rail portion 31 , four tilting blocks 40 , four tilting rods 41 and at least four anti-movement pins 50 .

Here, the frame body F is a rectangular frame body with four sides and has an opening in the center. The undercut portion U exists along the entire circumference of the inner surface of the frame F, and is formed by bending from below the side surface of the frame F toward the inner surface.

Now, the four outer slide cores 10 form the outer surfaces of the four sides of the frame F from the four directions outside the frame F. As shown in FIG. Here, the four outer slide cores 10 form the outer surfaces of the four sides of the frame F by the respective outer product surface forming portions. The outer rail portion 11 is provided on the outer slide core 10 and allows the outer slide core 10 to slide outward by means of an angular pin. Here, the product surface forming portion means a main constituent portion for forming the product surface such as the frame F among the slide cores. Further, the outer rail portions 11 are provided at both ends of the outer slide core 10 in a direction perpendicular to the sliding direction, and slide on outer rail guide portions (not shown).

In addition, the two first inner slide cores 20 are formed by the respective first inner product surface forming portions 20a, of the inner surfaces of the four sides of the frame F including the inner surface of the undercut portion U. Sides are formed from two directions inside the frame F. Here, the first inner product surface forming portions 20a of the two first inner slide cores 20 form the inner surfaces of two long sides of the rectangular four sides of the frame F. As shown in FIG. Moreover, as shown in FIG. 2, the first inner rail portion 21 is located at a predetermined first distance from each of both end portions 20a1 of the first inner product surface forming portion 20a of the first inner slide core 20 in the direction perpendicular to the sliding direction. The first inner slide core 20 can be slid inwardly by the angular pin. The first inner rail portions 21 are provided at both end portions of the first inner rail installation portion 20b of the first inner slide core 20, and slide on first inner rail guide portions (not shown). Here, the rail installation portion means a main component of the slide core for installing the rail portion.

In addition, the two second inner slide cores 30 are formed by the respective second inner product surface forming portions 30a so that, among the inner surfaces of the four sides of the frame F, the remaining two sides different from the two sides formed by the first inner slide core 20 are formed. Two inner side surfaces are formed from the inside of the frame F from two directions. Here, the two second inner slide cores 30 form the inner side surfaces of two short sides of the rectangular four sides of the frame F. As shown in FIG. Moreover, as shown in FIG. 2, the second inner rail portion 31 is arranged so that the first inner rail portion 21 does not come into contact with the second inner slide core 30 when the first inner rail portion 21 slides inward. The second inner product surface forming portion 30a of the second inner product surface forming portion 30a is provided by a predetermined second distance d2 from each of both ends 30a1 in the sliding direction and the perpendicular direction to the center side, and the second inner slide core 30 is moved inward by the angular pin. Make it slidable. The second inner rail portions 31 are provided at both ends of the second inner rail installation portion 30b of the second inner slide core 30, and slide on second inner rail guide portions (not shown).

Here, a first inner rail portion 21 is provided by a first distance d1 from each of both end portions 20a1 of the first inner product surface forming portion 20a toward the center side of the first inner product surface forming portion 20a, and the first inner product surface forming portion 20a Between each of the both end portions 20a1 of the surface forming portion 20a and the first inner rail portion 21 of the first inner rail installation portion 20b, there is a space without anything being provided. Further, a second inner rail portion 31 is provided from each of both end portions 30a1 of the second inner product surface forming portion 30a toward the center side of the second inner product surface forming portion 30a by a second distance d2, and a second inner product surface is provided. Between each of the both ends 30a1 of the forming portion 30a and the second inner rail portion 31 of the second inner rail installation portion 30b, there is a space without anything being provided. Thus, the length of both ends of the first inner rail installation portion 20b is shorter than the length of both ends of the first inner product surface forming portion 20a, and the length of both ends of the second inner rail installation portion 30b is By making the length shorter than the length of both ends of the second inner product surface forming portion 30a and providing a space in each of the first inner rail portion 21 and the second inner rail portion 31, the first inner slide core 20 and the second inner slide core 30 slide inward and approach each other, both end portions of the first inner rail installation portion 20b and the second inner rail installation portion 30b can move without interfering with each other. Therefore, the first inner slide core 20 and the second inner slide core 30 can be slid inward as much as possible.

Conventionally, the length of both ends of the first inner rail installation portion 20b is equal to the length of both ends of the first inner product surface forming portion 20a, and the length of both ends of the second inner rail installation portion 30b By making the length equal to the length of both ends of the second inner product surface forming portion 30a, the slidability (slidability) of each of the first inner rail portion 21 and the second inner rail portion 31 is improved. , in that case, the movement area of the first inner slide core 20 and the second inner slide core 30 is limited.

In the present invention, the length of both ends of the first inner rail installation portion 20b is set to the length of the first inner product surface forming portion to the extent that the slidability of the first inner rail portion 21 and the second inner rail portion 31 is not impaired. 20a, and both ends of the second inner rail setting portion 30b are shorter than the length of both ends of the second inner product surface forming portion 30a. This makes it possible to expand the movement area of the first inner slide core 20 and the second inner slide core 30 .

The four slanted blocks 40 form the square inner surface of the frame F from four directions inside the frame F, and are fitted to the first inner slide core 20 and the second inner slide core 30 respectively. (between the first inner slide core 20 and the second inner slide core 30). The four inclined rods 41 are connected to the four inclined blocks 40, as shown in FIG. After the mold is opened in step 1, the four inclined blocks 40 are pushed out to the square of the frame F and separated from the inner side surface of the square of the frame F.

Moreover, the at least four movement prevention pins 50 have the tip portions 50a forming part of the tip portions Ua of the undercut portions U on the four sides of the frame F, and as shown in FIG. At the same time, while holding a part of the tip portion Ua of the undercut portion U of the frame F, it is moved along the opening and closing direction of the mold 1, and relatively to the direction perpendicular to the opening and closing direction of the mold. The movement of the frame F is prevented. In FIG. 1, two anti-movement pins 50 are provided for one first inner slide core 20, and two anti-movement pins 50 are provided for one second inner slide core 30, for a total of eight anti-movement pins 50. exists. Also, the tilt rod 41 and the movement prevention pin 50 are supported by, for example, one ejector plate, and the movement of this ejector plate simultaneously moves the tilt rod 41 and the movement prevention pin 50 .

Thereby, it becomes possible to efficiently manufacture the frame F having the undercut portion U on the inner surface of each of the four sides. That is, in the present invention, as shown in FIG. 2, the first inner rail portion 21 is provided on the central side from both end portions of the first inner product surface forming portion 20a, and the second inner rail portion 31 is provided on the second inner product surface. By providing the forming portion 30a closer to the center than both ends, even if the first inner slide core 20 and the second inner slide core 30 slide inward, respectively or together, the first inner rail portion 21 and the second inner rail portion 21 slide. The first inner slide core 20 and the second inner slide core 30 can be separated from the inner side surfaces of the four sides of the frame F without coming into contact with the rail portion 31 . In other words, the movement area of the first inner slide core 20 and the second inner slide core 30 is expanded, and the first inner slide core 20 and the second inner slide core 30 are moved inside the frame F as much as possible. can be done. Therefore, even if the frame F has an undercut portion U that bends toward the inner surface, the first inner slide core 20 and the second inner slide core 30 can be separated from the undercut portion U, and the frame body The undercut portion U existing in the entire circumferential direction of the inner surface of F can be appropriately formed.

For example, in the present invention, the tip portion Ua of the undercut portion U has a predetermined length from the inner surface of the frame F (for example, when the frame F has a length of 250 mm to 900 mm and a width of 180 mm to 660 mm, the frame F The first inner slide core 20 and the second inner slide core 30 can be compactly moved inward even if the length from the inner surface of the frame F is 1 mm to 15 mm). It can be pulled away from the undercut part U by sliding.

Next, in the present invention, as shown in FIG. 3, the movement prevention pin 50, which forms a part of the tip portion Ua of the undercut portion U with the tip portion 50a, moves along with the movement of the inclined block 40 to move the tip portion of the undercut portion U. Follow while holding part of the part Ua. As a result, the four inclined blocks 40 moved along the direction inclined from the opening/closing direction of the mold 1 and separated from the square inner surface of the frame F, making the position of the frame F unstable. Even so, the movement prevention pin 50 holds a part of the tip portion Ua of the undercut portion U, so that the four inclined blocks 40 can be smoothly separated, and the position of the frame F can be stabilized. . For example, when the four inclined blocks 40 are separated from the square inner surface of the frame F to form the undercut portion U, the frame F One corner remains, and when the detachment of the frame body F is completed, the position of the frame body F may shift, and the next process may not proceed. In the present invention, by holding a part of the tip portion Ua of the undercut portion U with the tip portion 50a of the movement prevention pin 50, the frame body F can be moved relative to the direction perpendicular to the opening/closing direction of the mold 1. can be prevented and the position of the frame F can be stabilized. As a result, for example, when the frame F is taken out in the next step, the take-out means such as a robot can take out the frame F without dropping it. When the movement of the tilt block 40 and the movement prevention pin 50 is completed, the frame F is removed by, for example, removal means, and then the tilt block 40 and the movement prevention pin 50 are returned to their original positions at the same time.

As described above, in the present invention, when the mold is opened, the slide core process is performed, and then the inclined block process is performed, thereby efficiently forming the frame F having the undercut portion U on the inner surface side. can be manufactured. As a result, the price of the frame F, the price of the mold body, and the assembly man-hours in the urethane foaming process that is poured into the inner surface of the frame F are reduced. It is possible to improve the appearance quality of the outer surface (for example, to eliminate joints between four parts or to eliminate steps at joints between four parts). In particular, in the present invention, the structure of the first inner slide core 20 and the second inner slide core 30 is devised, and the movement prevention pin 50 is provided. Therefore, the frame F has a complicated shape. Nevertheless, simplification of the mold 1 is realized.

Here, the first distance d1 of the first inner rail portion 21 is not particularly limited. It is set within the range of 10 to 1/3. Both end portions 20a1 of the first inner product surface forming portion 20a are located at the tip portion of the first inner product surface forming portion 20a. Also, the second distance d2 of the second inner rail portion 31 is not particularly limited, but for example, 1/10 of the second overall distance d02 of both ends 30a1 of the second inner product surface forming portion 30a in the direction perpendicular to the sliding direction. It is set within the range of ~1/3. Further, both end portions 30a1 of the second inner product surface forming portion 30a are located at the tip portion of the second inner product surface forming portion 30a. As a result, the slidability of the first inner rail portion 21 and the second inner rail portion 31 is not impaired, and the strength of the first inner slide core 20 and the second inner slide core 30 is ensured. The movement area of the first inner slide core 20 and the second inner slide core 30 can be expanded.

On the other hand, when the first distance d1 of the first inner rail portion 21 is shorter than 1/10 of the first overall distance d01, or the second distance d2 of the second inner rail portion 31 is shorter than 1/10 of the second overall distance d02. If it is too short, the first inner rail portion 21 and the second inner rail portion 31 will immediately come into contact with each other, making it impossible to expand the movement area of the first inner slide core 20 and the second inner slide core 30. . Also, when the first distance d1 of the first inner rail portion 21 is longer than 1/3 of the first overall distance d01, or the second distance d2 of the second inner rail portion 31 is longer than 1/3 of the second overall distance d02. If it is too long, the slidability of each of the first inner rail portion 21 and the second inner rail portion 31 is impaired, and the strength of the first inner slide core 20 and the second inner slide core 30 is also reduced. Therefore, it is not preferable. The first distance d1 of the first inner rail portion 21 and the second distance d2 of the second inner rail portion 31 depend on the movement area of the first inner slide core 20 and the second inner slide core 30 and the size of the frame F. and shape.

Further, the angle α of the mating surfaces 40a of the inclined blocks 40 facing the first inner slide core 20 and the second inner slide core 30 with respect to the opening/closing direction of the mold 1 is not particularly limited. However, as shown in FIG. 3, for example, it is set larger than the tilt angle β indicating the moving direction of the tilt block 40 with respect to the opening/closing direction of the mold 1, and is within the range of 10 degrees to 30 degrees. It is preferable to do so. As a result, even if the four inclined blocks 40 existing in the square are simultaneously moved along the direction inclined from the opening/closing direction of the main mold 1 by the four inclined rods 41, the four inclined blocks 40 are moved to the first position. It is possible to reliably slip through the facing surfaces of the inner slide core 20 and the second inner slide core 30, and to properly separate the four inclined blocks 40 from the square inner surface of the frame F.

The cooling structure of the outer slide core 10, the first inner slide core 20, and the second inner slide core 30 is not particularly limited. A cooling channel is provided from the bottom surface of the second inner slide core 30 toward the inside, and water is run through the cooling channel to separate the outer slide core 10, the first inner slide core 20, and the second inner slide core 30. Allow to cool. This prevents thermal expansion of each of the outer slide core 10, the first inner slide core 20, and the second inner slide core 30 during injection molding, and stabilizes the product dimensions of the frame F. It becomes possible. In addition, since the first inner slide core 20 and the second inner slide core 30 are efficiently cooled, the inclined block 40 can be prevented from galling. Here, galling means that the contact pressure between either the first inner slide core 20 or the second inner slide core 30 and the inclined block 40 is strong, and the contact surface is locally welded due to the heat effect. .

The cooling structure of the inclined block 40 and the inclined rod 41 is not particularly limited. The inclined block 40 and the inclined rod 41 are cooled by running water. As a result, as described above, it is possible to reliably prevent galling between the first inner slide core 20 and the second inner slide core 30, and also reliably prevent galling with the guide that guides the inclined rod 41. .

Next, an injection molding method performed using the injection mold 1 according to the embodiment of the present invention will be described. First, as shown in FIG. 1, four outer slide cores 10 are slid inwardly by respective angular pins to form the outer surfaces of the four sides of the frame F, and two first inner slide cores. 20 and two second inner slide cores 30 slide outward to form the four inner surfaces of the frame F. Four inclined blocks 40 are fitted (fitted) between the first inner slide core 20 and the second inner slide core 30 to form a square inner surface of the frame F, and eight anti-movement pins 50 are attached to the frame. It forms a part of the tip portion Ua of the undercut portion U on the four sides of the body F. Four outer slide cores 10, two first inner slide cores 20, two second inner slide cores 30 and four inclined blocks 40 are arranged in the moving mold. If there is another mold group that forms the surface of the frame F that is not formed by these mold groups, another mold group is also arranged. By arranging these mold groups on the stationary side mold, the molds are clamped.

Next, molten resin is poured into four outer slide cores 10, two first inner slide cores 20, and two second inner slide cores from gates (resin injection ports) provided at predetermined positions of the stationary mold. It is injected into the space formed by the mold group including the core 30 and the four inclined blocks 40 . Here, the type of gate is not particularly limited, but for example, it may be a hot runner valve gate, which is installed at two predetermined positions of the fixed side mold, and the molten resin is injected. The number of gates is not particularly limited, and is set within a range of two to seven depending on the size of the frame F, the type of resin, and the like. The position of the gate is appropriately set by, for example, resin flow analysis. The space is filled with the injected resin and cooled to form a frame F corresponding to the space.

Next, when the cooling of the resin frame F is completed, the mold opening is performed by separating the fixed side mold from the moving side mold. Here, by opening the mold, as shown in FIGS. 3 and 4, the outer rail portion 11 slides the outer slide core 10 outward by the angular pin P, and the first inner rail portion 21 slides the first inner slide core. 20 is slid inward by the angular pin P, and the second inner rail portion 31 slides the second inner slide core 30 inward by the angular pin P (slide core step).

Specifically, each of the outer rail portion 11, the first inner rail portion 21, and the second inner rail portion 31 is provided with an inclined through hole H for the angular pin P. , the angular pin P provided on the fixed side mold is attached to each of the inclined through holes H of the outer rail portion 11, the first inner rail portion 21, and the second inner rail portion 31. , four outer slide cores 10 slide inward, and two first inner slide cores 20 and two second inner slide cores 30 slide outward. Then, when the movable mold is separated from the fixed mold during mold opening, the angular pins P of the fixed mold are moved to the outer rail portion 11, the first inner rail portion 21, and the second inner rail portion 21, respectively. It escapes from each inclined through hole H with the inner rail portion 31 . As a result, the outer slide core 10 is slid outward by the outer rail portion 11 sliding outward, and the first inner rail portion 21 and the second inner rail portion 31 are slid inward, whereby the first The inner slide core 20 and the second inner slide core 30 are slid inside. By simultaneously sliding the outer slide core 10, the first inner slide core 20, and the second inner slide core 30 when the mold is opened, production efficiency can be improved.

Here, as shown in FIGS. 2 and 5, the first inner rail portion 21 is centered by a predetermined first distance d1 from each of both end portions 20a1 in the direction perpendicular to the sliding direction of the first inner product surface forming portion 20a. The second inner rail portion 31 is provided closer to the side, and the second inner rail portion 31 is moved toward the center by a predetermined second distance d2 from each of both end portions 30a1 in the direction perpendicular to the sliding direction of the second inner product surface forming portion 30a. are provided. As a result, even if both the first inner slide core 20 and the second inner slide core 30 slide inward, the first inner rail portion 21 and the second inner rail portion 31 do not come into contact with each other. The inner slide core 20 and the second inner slide core 30 can be separated from the inner side surfaces of the four sides of the frame F.

Now, when the sliding of the outer slide core 10, the first inner slide core 20 and the second inner slide core 30 is completed, as shown in FIGS. The block 40 is moved along a direction inclined from the opening and closing direction of the mold 1 to be separated from the square inner surface of the frame F, and the eight movement prevention pins 50 are aligned with the undercut portion U of the frame F. While holding a part of the front end portion Ua of the mold 1, it moves along the opening/closing direction of the mold 1 (inclined block step).

When the pushing up of the four inclined blocks 40 and the movement of the eight anti-movement pins 50 are completed, the frame F can be obtained by taking out the frame F from there by a take-out means such as a robot. This time, the four inclined rods 41 and the eight anti-movement pins 50 move in the opposite direction and return to their original positions. , the outer rail portion 11 slides the outer slide core 10 inward by the angular pin P, the first inner rail portion 21 slides the first inner slide core 20 outward by the angular pin P, and the second inner rail portion 21 slides the first inner slide core 20 outward by the angular pin P. The rail portion 31 slides the second inner slide core 30 outward by means of the angular pin P. As a result, the mold is clamped. After that, the molten resin is again injected from the gate, and the molding of the frame F described above is repeated.

Thus, in the present invention, it is possible to form the frame F provided with the curved undercut portions U on the inner surfaces of each of the four sides. Here, in the present invention, the cross-sectional shape of the undercut portion U is substantially U-shaped. In addition, in the present invention, since the movement areas of the first inner slide core 20 and the second inner slide core 30 are enlarged as compared with the movement area of the conventional inner slide core, the undercut bent to the inner surface is formed. It is not limited to the portion U, and it is possible to form a frame having an outer undercut portion bent on the outer surface.

In addition, in the present invention, the mold 1 shown in FIGS. 1 to 8 has a structure in which the moving side mold moves vertically with respect to the fixed side mold, but there is no need to limit to this, and general In such a mold, there are various configurations in which the movable mold moves in the left-right direction or in the front-rear direction with respect to the stationary mold, so such a configuration may be used.

In addition, although there is no particular limitation on the use of the frame body F, for example, as described above, it is not limited to the door of a refrigerator. It can be used for the door of the dishwasher in the kitchen, the upper surface of the table, and the like. The inner plate attached to the frame F is not particularly limited, and non-printed glass, printed glass, resin plate, ceramic plate and the like can be mentioned.

As described above, the injection molding die and the injection molding method according to the present invention provide not only a frame body having undercut portions on the inner side surfaces of each of its four sides, but also a frame body having undercut portions on the inner and outer side surfaces. It is useful as an injection mold and injection molding method for manufacturing, and is effective as an injection mold and injection molding method that can efficiently manufacture a frame having undercut portions on the inner surfaces of each of the four sides. .

Reference Signs List 1 injection mold 10 outer slide core 11 outer rail portion 20 first inner slide core 21 first inner rail portion 30 second inner slide core 31 second inner rail portion 40 tilt block 41 tilt rod 50 movement prevention pin

Claims (4)

An injection mold for molding a frame provided with curved undercut portions on the inner surfaces of each of the four sides,
four outer slide cores forming the outer surfaces of the four sides of the frame from the four directions outside the frame;
an outer rail portion provided on the outer slide core and allowing the outer slide core to slide outward by means of an angular pin;
Of the four inner surfaces of the frame including the inner surface of the undercut portion, the inner surfaces of two opposing sides are formed from two directions inside the frame by the respective first inner product surface forming portions. two first inner slide cores;
The first inner slide core is provided by a predetermined first distance from both ends of the first inner product surface forming portion of the first inner slide core in the direction perpendicular to the sliding direction toward the center, and the first inner slide core is moved by an angular pin. a first inner rail portion that is slidable inward;
By the respective second inner product surface forming portions, of the four inner surfaces of the frame, the remaining two inner surfaces different from the two sides formed by the first inner slide core are formed into two inner surfaces of the frame. two second inner slide cores forming from the direction;
Both ends of the second inner product surface forming portion of the second inner slide core in the direction perpendicular to the sliding direction are a second inner rail portion provided a predetermined second distance from each of the rail portions toward the center, and allowing the second inner slide core to slide inward by means of the angular pin;
four inclined blocks that form square inner surfaces of the frame from four directions inside the frame and are provided to fit the first inner slide core and the second inner slide core, respectively;
It is connected to the four inclined blocks, the four inclined blocks can be moved along the direction inclined from the opening and closing direction of the main mold, and after the mold is opened, the four inclined blocks are attached to the squares of the frame body. four tilting rods that push the tilting block away from the square inner surface of the frame;
The tip portions form the tip portions of the undercut portions on the four sides of the frame, and along with the movement of the four inclined blocks, while holding the tip portions of the undercut portions of the frame, they move in the opening and closing direction of the mold. at least four movement prevention pins that move along and prevent movement of the frame relative to the direction perpendicular to the opening and closing direction of the mold;
Injection mold with The first distance of the first inner rail portion is set within a range of 1/10 to 1/3 of the first overall distance between both ends of the first inner product surface forming portion in the direction perpendicular to the sliding direction,
The second distance of the second inner rail portion is set within a range of 1/10 to 1/3 of the second overall distance between both ends of the second inner product surface forming portion in the direction perpendicular to the sliding direction,
The injection mold according to claim 1. The angle of the mating surfaces of the inclined blocks facing the first inner slide core and the second inner slide core with respect to the opening/closing direction of the mold is the inclination with respect to the opening/closing direction of the mold. It is set larger than the inclination angle indicating the movement direction of the block, and is within the range of 10 degrees to 30 degrees,
The injection mold according to claim 1. An injection mold for molding a frame provided with curved undercut portions on the inner surfaces of each of the four sides,
four outer slide cores forming the outer surfaces of the four sides of the frame from the four directions outside the frame;
an outer rail portion provided on the outer slide core and allowing the outer slide core to slide outward by means of an angular pin;
Of the four inner surfaces of the frame including the inner surface of the undercut portion, the inner surfaces of two opposing sides are formed from two directions inside the frame by the respective first inner product surface forming portions. two first inner slide cores;
The first inner slide core is provided by a predetermined first distance from both ends of the first inner product surface forming portion of the first inner slide core in the direction perpendicular to the sliding direction toward the center, and the first inner slide core is moved by an angular pin. a first inner rail portion that is slidable inward;
By the respective second inner product surface forming portions, of the four inner surfaces of the frame, the remaining two inner surfaces different from the two sides formed by the first inner slide core are formed into two inner surfaces of the frame. two second inner slide cores forming from the direction;
Both ends of the second inner product surface forming portion of the second inner slide core in the direction perpendicular to the sliding direction are a second inner rail portion provided a predetermined second distance from each of the rail portions toward the center, and allowing the second inner slide core to slide inward by means of the angular pin;
four inclined blocks that form square inner surfaces of the frame from four directions inside the frame and are provided to fit the first inner slide core and the second inner slide core, respectively;
It is connected to the four inclined blocks, and the four inclined blocks can be moved along the direction inclined from the opening and closing direction of the main mold, and after the mold is opened, the four inclined blocks are attached to the squares of the frame body. four tilting rods that push the tilting block away from the square inner surface of the frame;
The tip portions form the tip portions of the undercut portions on the four sides of the frame, and along with the movement of the four inclined blocks, while holding the tip portions of the undercut portions of the frame, they move in the opening and closing direction of the mold. at least four movement prevention pins that move along and prevent movement of the frame relative to the direction perpendicular to the opening and closing direction of the mold;
An injection molding method for an injection mold comprising
When the mold is opened, the outer slide core is slid outward by the angular pin, the first inner slide core is slid inward by the angular pin, and the second inner slide core is moved. a slide core step of sliding inward by the angular pin;
The four inclined blocks are moved along a direction inclined from the opening/closing direction of the main mold to separate from the square inner surface of the frame, and the movement prevention pin is moved to the tip of the undercut portion of the frame. An inclined block step of moving along the opening and closing direction of the mold while holding a part of the part;
An injection molding method using an injection mold.

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