JPH0338023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the invention of a die-casting mold apparatus, and the present invention relates to the invention of a die-casting mold apparatus, and the present invention relates to a die-casting mold apparatus that uses an intermediate mold between a movable mold and a fixed mold. The mold operation can be carried out smoothly and accurately, and stable operation can be carried out without interruption in a mass-production production line.

Although die casting has been conventionally performed using an intermediate mold between a movable mold and a fixed mold, it is not always easy to open the mold accurately. In other words, such die-casting molds generally use a fixed mold and a movable mold, and pressurize and inject molten metal from the injection mechanism part formed in the fixed mold into the cast part of the movable mold, and then separate the two molds. At the very least, it is only necessary to take out the product molded in the cast part, but when injection molding a large number of products simultaneously and in mass production, or when injection molding large castings, it is necessary to use a movable mold. A plurality of cast parts or large-sized cast parts are engraved, and molten metal from a fixed injection mechanism part is evenly distributed and supplied to the movable cast parts, and in the process of distributing and supplying such molten metal. In order to make the temperature drop conditions of the molten metal uniform, a so-called three-piece type is used in which an intermediate mold is interposed between the fixed mold and the movable mold as described above. It is necessary to form within the intermediate mold region a branch runner section that forms an even runner between the cast members and a pin runner section connected to the branch runner section to supply hot water to each cast section. A die-casting mold having such a configuration will be explained using drawings as shown in FIGS. An intermediate mold 24 is used between the movable mold 21 and a branch runner from the biscuit portion 27 of the fixed mold 23 by an injection tip 26 at the forward end of an injection rod 26a operated in an injection sleeve 25 provided on the fixed platen 22. The pin runner part 29 of the intermediate mold 24, the gate 30,
Molten metal is injected into a cavity 31 of a movable mold 21 and cast under pressure. In the movable mold 21, an extrusion pin 34 operated by an extrusion rod 32 and an extrusion plate 33 on the side of the movable platen 20 is attached to the cavity 3.
The mold is designed to extrude and release the product 35 (see Fig. 3) formed in Fig. 1, and the mold opening after casting in the state shown in Fig. 1 is as shown in Fig. 2 and below. It is. In other words, the intermediate mold 24 is replaced by the fixed mold 2.
The movable mold 21 is separated from the intermediate mold 24 after the gate 30 is cut by the mold opening force. After the mold opening between the fixed mold 23 and the intermediate mold 24 is completed, the mold opening between the intermediate mold 24 and the movable mold 21 is performed using, for example, a drive cylinder provided behind the movable platen 20 or the fixed mold 23. Intermediate type 24
The movable platen 20's mold opening force is used as the driving source for the intermittent rod, but the main purpose of mold opening between the fixed mold 23 and the intermediate mold 24 is to use the pin runner 29a, the tree branch, etc. The runner 28a, biscuit 27a, etc. are fixed to the mold 23.
The purpose is to remove only the intermediate mold 24 while leaving it properly on the side. After the intermediate mold 24 is released, the pin runner 29a and the branch runner 2 are moved forward by the injection rod 26a as shown in FIG.
8a and biscuit 27a is released from the mold and discharged. However, in order to release the intermediate mold 24 while leaving the integral part from the biscuit 27a to the pin runner 29a on the fixed mold 23 side, it is necessary to remove the entire mold between the intermediate mold 24 and the pin runner 29a. It is necessary that the resistance value ΣR ₁ is smaller than the total mold release resistance value ΣR ₂ between the fixed mold 23, the tree runner 28a and the biscuit 27a. However, even if the initial design is such that the relationship ΣR ₁ < ΣR ₂ can be obtained, ΣR ₁ will increase significantly during the long-term production process, which will lead to the occurrence of seizure at the product gate.
Since the pin runner portion 29 is structurally difficult to use a mold release agent accurately, the occurrence of seizure in this portion will combine to significantly increase ΣR ₁ , resulting in the above-mentioned ΣR ₁ < ΣR ₂ . This makes it difficult to maintain a relationship. If the relationship ΣR ₁ < ΣR ₂ of the lid is not maintained, the integral part will remain stuck to the intermediate mold 24 as shown in FIG. 4, and the automatic line production process will be interrupted, preventing smooth operation. I don't get it. In addition, if excessive resistance occurs in a part of a device having a plurality of pin runner parts 29, breakage will occur between the runner part and the remaining integral part, resulting in runner clogging. It is necessary to push it out from the gate hole with a pin, etc., but the area around the gate is often damaged or the pin is bent and cannot be pulled out.In any case, recovery measures are extremely difficult, and of course the line will be interrupted. I don't get it. Therefore, in order to avoid these disadvantages, the intermediate mold 2 is used as a fitting part body in which the pin runner part is formed separately.
4, and if the runner becomes clogged, the fitting part body can be replaced with a spare part, the taper of the pin runner part can be increased to make it easier to pull out, and the entire structure of the intermediate mold 24 can be inserted into the piece. Although it has been considered to make the structure into a type, it would make the structure more complicated and difficult to handle, or it would lower the casting yield, cause burrs, and other disadvantages, so none of these methods are preferred.

In addition, by providing a convex part on the fixed mold so that when the molten metal solidifies and shrinks after injection molding, it tightly surrounds the outer periphery of the convex part and makes it difficult to separate from the fixed mold, thereby allowing the pin runners and branch runners to adhere to the fixed mold. It has also been considered to release both runners from the fixed mold by moving the injection mechanism part forward again after that, but even if such a method is adopted, the position of the convex part provided on the fixed mold will be too high for injection. If the runner is located far away from the mechanism part, when the injection mechanism part is moved forward again after injection molding, only the runner near the injection mechanism part will be released from the mold, and the convex part located further away from the injection mechanism part will be removed. A runner that has solidified in close contact with the mold is difficult to release from the mold, and this poses a problem that greatly hinders subsequent casting operations.

The present invention has been devised after repeated studies in view of the above-mentioned circumstances, and by adopting a specific configuration for the fixed part, it is possible to avoid the above-mentioned disadvantages and to achieve long-term production. We succeeded in ensuring stable and reasonable mold release during the process. That is, a specific embodiment of the present invention shown in the accompanying drawings will be described. It is as shown in FIG. An intermediate mold 4 is used between the fixed mold 3 and the fixed mold 3 by an injection mechanism 6 operated within an injection sleeve 5 provided on the fixed platen 2.
As mentioned above, the structure is such that the molten metal is injected from the biscuit part 7 of the mold through the branch runner part 8, the pin runner part 9 of the intermediate mold 4, and the gate 11 into the cavity 12 of the movable mold 1 for pressure molding. 1st
A pin head molding part 3a that is similar to that in Figures 4 to 4, but has at least a partially enlarged diameter in the region of the fixed mold 3 that contacts the pin runner part 9 as described above.
At the same time, an engaging protrusion 3b that protrudes from the fixed mold 3 into the width of the head of the pin runner 9a is formed on one side of the pin head molded part 3a, and on the other side of the pin head molded part 3a. The mold surface is a circular arc surface or other surface 3e that can be rotated and removed from the mold around the engaging protrusion 3b.
In the illustrated example, the portion that abuts the pin runner portion 9 has a relatively large diameter, and
Moreover, the other side of the top surface is a hemispherical or semicircular surface 3e that can be rotated and removed from the mold. Further, a typical example of the structure between the tree runner 8 and the pin runner 9 is shown in FIG.

The above-mentioned engaging protrusion 3b ensures that the intermediate mold 4
The pin runner 9a, which has been released from the mold more, is positioned above the front part of the fixed mold 3 as described above, that is, above the portion corresponding to between the intermediate mold 4 and the fixed mold 3 in FIG. A dispensing machine 15 is provided for the dispensing machine 9a.
5 to operate the pin runner 9a. Of course, such a dispensing machine 1
The pin runner 9a can also be removed from the fixed mold 3 manually without using the pin runner 5.

To explain the operation of the device according to the present invention as described above, as shown in FIGS. 5 to 8,
As shown in FIG. 5, the intermediate mold 4 and the movable mold 1 are set on the fixed mold 3, and by operating the injection mechanism 6 of the injection sleeve 5, the biscuit part 7, the tree runner part 8, and the pin runner part 9 are made. The molten metal can be injected into the cavity 12 of the movable mold 1 through the gate 11 to perform pressure molding. When the intermediate mold 4 is removed from the fixed mold 3 after molding in the state shown in FIG. 5, a pin runner 9a is formed as shown in FIG.
is securely engaged with the above-mentioned locking protrusion 3b of the fixed mold 3, and is accurately released from the intermediate mold 4. Thereafter, the movable mold 1 is separated from the intermediate mold 4, and the product 18 is released by operating the ejecting pin 14. is released from the cavity 12 of the movable mold 1. In this series of operations, depending on the shape of the product, the intermediate mold 4 and the movable mold 1 can be separated before the intermediate mold 4 is removed from the fixed mold 3. When the pin runner 9a is reliably left on the fixed die 3 as described above and the dispensing machine 15 is operated manually or as shown in FIG. ) is engaged with the locking protrusion 3b of the fixed mold 3, a discharging force is applied from the surface 3e on the other side which can be rotated and removed, that is, one side of the head of the pin runner 9a is held on the fixed mold 3.
Since a discharging force is applied to the distal end side of the pin runner 9a in a state in which it is locked to As shown in FIG. 7, it can be accurately dispensed using rotational force. After the pin runner 9a is removed in this way, the extrusion force of the injection mechanism 6 is applied to the biscuit 7a, as shown in FIG. It is clear that the product 18 in the movable mold 1 is forcibly removed by the extrusion pin 14 provided in the movable mold 1 being pushed out by the extrusion plate 13, and there is no problem with conventional methods. It is similar to that.

A typical planar example of the structure of the tree runner 8a and pin runner 9a is as shown on the left side of FIG. 9, and the connection between the pin runner 9a and the tree runner 8a is constricted as shown in FIG. By forming the portion 19, it is possible to easily break and separate the pin runner 9a when discharging it as described above. The shape of the head 9d of the pin runner 9a is typically as shown in FIGS. 11 and 12, and the one in FIG. 11 has a head 9d with a larger diameter mainly on the lower side of the pin runner 9a, A relatively wide undercut portion 9c is formed on the head 9d to ensure accurate engagement with the locking protrusion 3b as described above.
A rotary demolding surface 9e centered on the tip of the undercut portion 9c is formed on the upper side, and as shown in FIG. A head portion 9d having a larger diameter may be formed, and an undercut portion 9c may be formed in a portion having a width equal to or less than the lower pin runner 9a.
A rotary demolding surface 9e centered at c is formed. It goes without saying that the undercut portion 9c does not have to be a curved surface as shown in FIGS. 11 and 12, but may also be an inclined surface as shown in FIG. 13.

According to the present invention as explained above, an intermediate mold is interposed between a fixed mold and a movable mold, a branch runner part is formed in the fixed mold via a biscuit part in front of the injection mechanism, and a branch runner part is formed in the movable mold through a biscuit part in front of the injection mechanism. The molten metal from the tree runner section is injected and pressurized through each pin runner section formed in the intermediate mold to the plurality of formed or large-sized cast sections, and the products are simultaneously produced in each cast section or large-sized cast section. In addition, in the case of mass-produced molding, a pin head molding part having at least a partially enlarged diameter is formed in the fixed mold area that abuts each of the pin runner parts, and the pin head molding part is formed on one side of the pin head molding part. Since the engaging protrusion protruding from the fixed mold into the pin head molding part is formed, the engaging protrusion protrudes into the intermediate mold area when the intermediate mold is separated from the fixed mold during mold release after injection molding as described above. Even if the formed pin runner is provided far from the injection molding mechanism part, the formed pin runner is always released from the mold in a state where it is properly bonded to the fixed mold, that is, the formed pin runner is formed on the pin runner part or its tip. Even under conditions where the mold release resistance becomes excessive due to seizure or the like during a long-term production process in the gate part where the molding is performed, smooth mold release conditions can be ensured between the pin runner and the intermediate mold. A dispensing machine is provided at a position above the front of the fixed mold to press the pin runners tied to the fixed mold in one direction, and the dispensing machine is applied after the intermediate mold is released as described above, or the dispensing force is applied manually. As a result, it is possible to apply an overturning moment to the pin runner around the engagement protrusion and cause the pin runner to be accurately ejected from the fixed mold from the surface that can be rotated and removed from the mold. This enables smooth pressure forming and mold release operations over a long period of time in mass-production die casting mold equipment, and furthermore, by separating the pin runner from the tree runner on the fixed mold side as described above. This invention is industrially highly effective because it facilitates the work of arranging and handling them outside the casting machine, and in any case enables efficient, mass-produced die-casting to be carried out appropriately.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, in which Fig. 1 is a sectional view of a conventional die-casting mold device in a casting state, Figs. 2 to 4 are explanatory diagrams of the mold release situation, FIG. 5 is a sectional view showing the casting state of the product according to the present invention, and FIGS.
The figures are cross-sectional views showing step-by-step the mold release operation, Figure 9 is a front view of the branch runner and pin runner, and Figure 10 is a partial slope showing the joint between the branch runner and pin runner. 11 and 12 are explanatory views showing the structure of the pin runner head portion from the side and the front, respectively, and FIG.
The figure is an explanatory view showing still another embodiment of the pin runner head from the side and from the front. However, in these drawings, 1 is a movable type, and 2 is a movable type.
3 is a fixed platen, 3 is a fixed mold, 3a is a pin head molding part, 3b is its engaging part, 3e is a rotatable surface, 4 is an intermediate mold, 5 is an injection sleeve, 6 is an injection mechanism, and 7 is a Biscuit part, 7a is biscuit, 8 is tree runner part, 8a is tree runner, 9 is pin runner part, 9a is pin runner, 9c is undercut part, 9d is head, 9e is rotating demolding surface, 1
0 is a fixed platen, 11 is a gate, 12 is a product cavity, 15 is a dispensing machine, and 18 is a product.

Claims (1)

[Claims] 1. An intermediate mold is interposed between the fixed mold and the movable mold, a branch runner part is formed in the fixed mold via a biscuit part in front of the injection mechanism, and the intermediate mold is inserted into the cavity part formed in the movable mold. In a die-casting mold device that injects and pressurizes molten metal from the branch runner portion through a pin runner portion formed in the die-casting mold device, the diameter is increased at least partially within a fixed mold region that abuts the pin runner portion. forming a pin head molding part, forming an engaging protrusion protruding from the fixed mold into the pin head molding part on one side of the pin head molding part, and forming a mold surface on the other side of the pin head molding part. It is characterized by having a surface that can be rotated and removed from the mold around the engaging protrusion, and a pin runner formed by being connected to the fixed mold is pressed in one direction to generate an overturning moment around the engaging protrusion. A die-casting mold device capable of releasing the pin runner from the fixed mold.