JPH038413Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an injection mold structure for injection molding a molded product having an undercut portion with a large product surface area.

(Prior Art) Conventionally, this type of injection mold has had a structure as shown in FIG. 4 or FIG. 5. That is, the mold shown in FIG. 4 consists of a movable mold 27, a fixed mold 20, and a slide core 22 having an undercut molding part 24, and the slide core 22 is placed on the movable mold 27. It is placed so that it can slide freely. The slide core 22 is provided with an inclined guide hole 23 that is inclined in the mold closing direction, while the fixed mold 20
An inclined guide rod 21 that can be inserted into an inclined guide hole 23 is integrally provided in the holder. When the mold is closed, the inclined guide rod 21 is inserted into the inclined guide hole 23, so that the slide core is positioned at a predetermined molding position. Further, the back surface of the slide core 22 and the fixed mold 20 are provided with contact surfaces 26a, 26b which are also inclined in the mold closing direction, and are configured to receive injection molding pressure on both contact surfaces 26a, 26b.

Further, the mold shown in FIG. 5 has a slide core 22 slidably housed in a fixed mold 20, and a cylinder 2 in which the slide core 22 is provided in the fixed mold 20.
5, the slide core 22 is positioned at a predetermined molding position by the operation of a cylinder 25, and the cylinder 25 receives injection molding pressure.

(Problem to be Solved by the Invention) However, in the mold structure shown in FIG. Not only does it have a structure that holds the slide core 22 in a cantilevered manner away from the parting surface (line) of
The inclination angle of the inclination guide hole 23 and the inclination guide rod 21
There is a restriction that the inclination angle cannot be made smaller ^than the inclination angle of The problem was that deterioration was unavoidable. In addition, when the slide core 22 has an undercut molded part 24 with a large area as described above, the molded product 28
A considerable amount of force is required to pull out the slide core 22 from the undercut portion of the slide core 22, and it will be difficult to pull it out unless the molded product 28 is tightly restrained. However, in this mold structure, when the mold is opened after injection molding, the inclined guide rod 21 is inserted into the inclined guide hole 2.
3 and move the slide core 22, the slide core 22 is pulled out from the undercut part when the molded product 28 is separated from the restraint of the fixed mold, and unreasonable force is applied to the molded product. There was a risk of deformation or cracking.

On the other hand, in the mold structure shown in Fig. 5, the injection molding pressure is exclusively applied to the cylinder 25, and considering that the pressure of general-purpose cylinders is 70 to 100 kg/ ^cm2 , this cylinder 25 is extremely large. As mentioned above, the problem was that the overall size of the mold was unavoidable.

Therefore, in order to eliminate the above-mentioned drawbacks, the present invention aims to provide an injection molding mold structure that can efficiently receive the injection molding pressure applied to the slide core, thereby achieving miniaturization. .

(Means for Solving the Problem) In order to achieve this objective, the present invention uses injection molding in which an injection molding cavity is formed by a movable mold, a fixed mold, and a slide core having an undercut molding part. In the mold, a core guide hole is provided in the fixed mold in a direction perpendicular to the mold closing direction, the slide core is slidably inserted into the core guide hole, and the slide core is inserted in the mold closing direction. A rod guide of the fixed mold is provided with an inclined guide hole which is inclined to the center, and an inclined guide rod having a concave surface at the tip is slidably inserted into the inclined guide hole, and is provided perpendicularly to the core guide hole. The base of the slanted guide rod is slidably inserted into the hole, and the base of the slanted guide rod is connected to a cylinder installed in the fixed mold. The present invention is characterized in that it forms wedge-enabled mating surfaces, and wedges the mating surfaces together in the closed state of the mold.

(Function) With this configuration, the movable mold is clamped to the fixed mold, and the inclined guide rod driven by the driving means can move through the rod guide hole and the inclined guide hole provided in the slide core. slide. At this time,
The slide core with undercut molding part is
Due to the above-mentioned sliding movement, the product is slid to the molding position. At the same time, when the tip surface of the inclined guide rod is in contact with the tip surface of the movable mold and injection molding is performed, the injection molding pressure applied to the slide core is applied to the tip surface and the bar guide through the inclined guide rod. Since it is applied to the hole wall, the capacity of the cylinder only needs to be enough to move the inclined guide rod up and down. In addition, since the inclined guide rod is connected to the cylinder to move the slide core independently of the movement of the mold, the slide core can be pulled out from the undercut of the molded product when the mold is closed. .

(Example) An example according to the present invention will be described in detail based on the drawings.

Figure 1 shows the main parts of the injection mold structure of the present invention, in which a movable mold 2 is clamped to a fixed mold 1, and a slide core 3, fixed mold 1, and movable mold 2 are connected. The figure shows a state in which a molded product 6 is formed by injecting molten synthetic resin into the cavity 5 formed during the process. The slide core 3 has an undercut molded part 7 facing the cavity 5, and is fitted into a core guide hole 8 provided horizontally along the lower part of the fixed mold 1. Further, the slide core 3 has an inclined guide hole 9 penetrating from its upper surface to its lower surface, and the inclined guide hole 9 is inclined downward in a direction away from the cavity 5 with respect to a vertical line. . moreover,
A rod guide hole 10 penetrates the fixed mold 1 from above toward the contact surface with the movable mold 2, orthogonal to the core guide hole 8. A large-diameter stepped portion 11 is formed above the rod guide hole 10, and a cylinder 13 is located in this stepped portion 11, with a piston 12 facing downward, as driving means for forward and backward movement. An upper part 15 of an inclined guide rod 14 is connected to the tip of the piston 12 so as to be guided in the rod guide hole 10 and slidable up and down. The inclination angle of the inclination guide rod 14 is the same angle with respect to the inclination of the inclination guide hole 9 formed through the slide core 3 with respect to a vertical line. This inclined guide rod 14
When inserted into the inclined guide hole 9, the slide core 3 moves toward or away from the cavity 5 by vertical movement of the inclined guide rod 14, as partially shown in FIGS. 2 and 3. Sliding.

Furthermore, a tipped surface 16 is formed at the tip of the inclined guide rod 14 so as to be inclined in the opposite direction to the direction in which the inclined guide rod 14 is inclined. On the other hand, when the inclined guide rod 14 is lowered, the movable mold 2 has a tip surface 1.
The contact surfaces 17 are formed at the same inclination angle so that the contact surfaces 6 are in contact with each other. Kotsuta side 16 is Kotsuta side 17
The inclined guide rod 14 is in its lowest position when it comes into contact with the slide core 3, and at the same time the slide core 3 is in the position where it is to be molded to form the cavity 5.

In the injection mold structure shown in FIG. 1, the spool and gate indicating the route for injecting the molten resin, the attachment of the movable mold 2 and the fixed mold 1, etc. are not shown.

In this embodiment, a slide core 3, an inclined guide rod 14 that slides the slide core 3, and a cylinder 1
3 was provided on the fixed mold 1 side, but this was installed on the movable mold 2 side.
It may be placed on the side.

Next, the effect will be explained. First, movable mold 2
is usually at an initial position away from the fixed mold 1. A movable mold 2 is clamped to a fixed mold 1 to form a cavity 5. At this stage, the slide core 3 does not form the cavity 5 part. This corresponds to the view shown in FIG. 2 with the molded product 6 removed.
After the mold is clamped, the cylinder 13 is driven to lower the inclined guide rod 14. Following this descent,
The inclined surface of the inclined guide rod 14 slides on the inclined inner surface of the slide core 3, so that the slide core 3
slides to form part of the cavity 5. The slide core 3 stops sliding at the position where the tipped surface 16 of the inclined guide rod 14 contacts the tipped surface 17 of the movable mold 2, so that it can withstand the injection pressure inside the cavity 5.

In this way, when the molten resin is injected and molded, a large injection molding pressure of 500 to 600 kg/cm ² is applied to the slide core 3.

However, this large load is applied to the tipped surface 16 of the inclined guide rod 14 and its upper part 15 through the inclined inner surface of the slide core 3, regardless of the capacity of the cylinder 13, and is further applied to the tipped surface 17 of the movable mold 2. and the inner wall of the rod guide hole 10,
The displacement of the slide core 3 is suppressed. Therefore,
Even in the injection molding of the undercut molding part 7 having a large surface area, a cylinder with a small capacity sufficient to move the inclined guide rod 14 up and down can be used.

After injection molding, as shown in Fig. 2, when the inclined guide rod 14 is raised by operating the cylinder 13 while the mold is kept in the closed state, the slide core 3 slides away from the cavity and slides. The undercut molded portion 7 of the core 3 is removed from the molded product 6. At this time, since the molded product 6 is restrained by both molds 1 and 2, the molded product 6 will not be deformed or cracked. Thereafter, as shown in FIG. 3, the movable mold 2 returns to the initial position, thereby completing one process.

(Effects of the invention) From the above, since the slide core is subjected to large injection molding pressure by the inclined guide rod supported on both sides, it is possible to make the slide core large or use a large cylinder. This eliminates the need to support the slide core, and the mold structure can be significantly downsized. Incidentally, according to the present invention, the area occupied by the parts required for processing the undercut portion is reduced by approximately 35% and the size of the mold is reduced by approximately 15%, resulting in a reduction in mold cost. , was reduced by approximately 15%, and the operating cost of the molding machine was reduced by approximately 10% due to the smaller equipment. This made it possible to reduce manufacturing costs by approximately 5%.

Furthermore, the degree of freedom in designing the mold increases, thereby increasing the degree of freedom in designing the molded product. Moreover,
Since the undercut molded portion can be removed from the molded product by moving the slide core in the mold closed state, the molded product 6 will not be deformed or cracked.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing the injection mold structure of the present invention, Fig. 2 is a longitudinal sectional view showing the slide core separated from the molded product after injection molding, and Fig. 3 is a longitudinal sectional view showing the injection mold structure of the present invention. After molding, the movable mold is separated from the fixed mold and is in its initial position. Figure 4 is a vertical cross-sectional view showing the conventional slide core mold structure. Figure 5 is the conventional core puller mold structure. FIG. 1: Fixed mold, 2: Movable mold, 3: Slide core, 5: Cavity, 8: Core guide hole, 9: Inclined guide hole, 10: Rod guide hole, 14: Inclined guide rod, 16: Kotta Mask, 17: Kotsuta surface.

Claims (1)

[Scope of utility model registration request] In an injection molding mold in which an injection molding cavity is formed by a movable mold, a fixed mold, and a slide core having an undercut molding part, the core is attached to the fixed mold in a direction perpendicular to the mold closing direction. A guide hole is provided, and the slide core is slidably inserted into the core guide hole, an inclined guide hole is provided in the slide core that is inclined in the mold closing direction, and a tip surface is provided at the tip of the inclined guide hole. The base of the inclined guide rod is slidably inserted into the rod guide hole of the fixed mold provided perpendicularly to the core guide hole, and the base of the inclined guide rod is slidably inserted. Connecting the base of the inclined guide rod to a cylinder installed in the fixed mold, forming a tipped surface on the movable mold that can be wedged with the tipped surface of the inclined guide rod,
An injection mold structure characterized in that both of the contact surfaces are wedged together when the mold is closed.