JPH0224522Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a moving core for molds, and in particular, it is attached to molds such as die-casting molds and low-pressure casting molds.
This invention relates to a movable core that can be moved forward and backward into a product cavity together with a mold to define the product cavity.

[Conventional technology]

BACKGROUND ART Moving cores (also referred to as movable cores) have conventionally been used in molds such as die-casting molds. This moving core is used to form recesses and holes that must be pulled out at right angles or at a certain angle to the direction of opening and closing of the mold. 1980/10/
30, Maruzen, P1486-1487).

An example of such a conventional moving core will be explained with reference to FIG. 4.

In FIG. 4, 1 is a fixed mold (mold),
2 is a movable mold (mold). This movable type 2 has
A sliding hole for the moving core 3 is provided, and the moving core 3 is movable by a hydraulic cylinder (not shown). This moving core 3 usually has an insert part 4 that comes into direct contact with the molten metal, and a holder part 5 that supports this insert part 4. They are held together by fastening means. Then, the fixed mold 1, the movable mold 2, and the movable core 3 define a product cavity 6 corresponding to the desired product shape.

After moving the moving core 3 forward to the state shown in FIG. 4, a molten metal such as an aluminum alloy is injected into the product cavity 6. After the molten metal has solidified, the moving core 3 is pulled out. At this time,
The insert portion 4 of the moving core 3 is tightly tightened due to solidification and shrinkage of the aluminum alloy, and therefore cannot be easily released from the mold. That is, in order to overcome the clamping force of the product and pull out the moving core 3, a considerable amount of force is required, and if the product is large, it may weigh 40 to 80 tons.

As described above, in the conventional moving core 3, a large amount of force is required to pull out the moving core 3 from the product after casting, and as a result, the driving means for pulling out, such as a hydraulic cylinder, becomes large and takes up a lot of space. There are problems such as overuse and the need for larger molds.

Therefore, as a technique to solve the above problem, for example, as disclosed in Japanese Patent Publication No. 59-500360, there is a technique in which a drawing core divided into two parts can be easily pulled out in two stages. It was hot.

[The problem that the idea aims to solve]

In this way, in a structure in which the two-divided drawing core is easily pulled out in two stages, the insert part 4
Unlike the integrated type, the pulling force of the drawing core can be reduced, and therefore the driving means for drawing out, such as a hydraulic cylinder, can also be downsized.

However, with the above-mentioned split type drawing core,
Since the sliding surfaces of the two-part drawing core are in contact with each other on the entire surface of the split surface, the sliding resistance when the drawing core is pulled out is large, and the sliding surface of the two-part drawing core is If tension occurs, the sliding resistance when the drawing core is pulled out becomes even greater, and two-stage drawing may not be possible depending on the casting being caught.

Therefore, the pulling force of the drawing core can be reduced,
In addition, there was a desire for a device that would allow reliable two-step extraction with a simple structure.

[Means to solve the problem]

The above problem is solved by the moving core for molds of the present invention, which will be described below.

That is, the movable core for a mold of the present invention is a movable core that is attached to a mold and can move freely into and out of the product cavity in order to define the product cavity together with the mold. , a nesting part that comes into direct contact with the molten metal,
The insert part is divided into a fixed insert and a movable insert, and the sliding surface of the movable insert that comes into contact with the fixed insert is partially non-contacted. The fixed insert is integrated with the holder portion, and the movable insert is movable a predetermined distance with respect to the holder portion.

[Effect]

According to the movable core for molds of the present invention, unlike conventional mold inserts, the insert part of the movable core is divided into a movable insert and a fixed insert, and the movable insert is a predetermined distance (predetermined stroke) from the fixed insert. Since the movable insert is movable and a non-contact space is formed partially on the sliding surface of the movable insert that comes into contact with the fixed insert, when the molten metal is pulled out after casting is completed and the molten metal has solidified, the movable insert is first removed from the product. Only the fixed insert separates from the product in the sandwiched state. Next, after the fixed insert moves a predetermined distance, the movable insert resists the clamping force of the product and separates from the product. That is, in the moving core of the present invention, the fixed insert and the movable insert move differentially, so the force required to pull out the moving core can be significantly reduced compared to the conventional method, and the sliding of the movable insert can be significantly reduced. Since a non-contact space is partially formed on the surface, the sliding resistance between the inserts can be reduced, and the casting between the inserts can be easily removed by differential movement between the fixed insert and the movable insert. Can be done.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

Here, FIG. 1 is a schematic configuration diagram showing a state in which a moving core for a mold according to an embodiment of the present invention is attached to a die-casting mold, and FIG. 2 is a diagram showing a state of the moving core immediately after pouring. FIG. 3 is an enlarged sectional view of section A in FIG. 1, showing the state of the moving core during a mold release operation.

In the figure, 1 is a fixed mold (mold), and 2 is a movable mold (mold). This movable mold 2 includes a movable core 3
A sliding hole is provided, into which the movable core 3 is inserted so as to be movable forward and backward. A product cavity 6 is defined by the fixed mold 1, movable mold 2, and moving core 3. This moving core 3 has an insert part 4 that comes into direct contact with the molten metal, and a holder part 5 that supports this insert part 4.
It is said to be able to move forward and backward at will.

The holder portion 5 is formed with a stepped portion 8 for positioning the movable core 3 with the movable mold 2, and the bottom portion is formed with a recess 9 into which a portion of the movable insert, which will be described later, can be inserted. On the other hand, the insert part 4 consists of a cylindrical fixed insert 10 and a cylindrical movable insert 11, and the movable insert 11 is slidable a predetermined distance within a guide hole 12 inside the fixed insert 10. Ru. The tip of the fixed insert 10 projects into the product cavity 6 in a cylindrical shape to form a space in the product. The fixed insert 10 is integrally fixed to the holder portion 5 by bolts 14 passed through the mounting member 13, and moves forward and backward into the product cavity 6 in accordance with the operation of the hydraulic cylinder 7. Moreover, spaces 15 and 16 are formed in each sliding surface of the fixed insert 10 and the movable insert 11 in order to reduce sliding resistance and to facilitate removal of the casting.

The movable insert 11 has a head 18a attached to the mounting member 13.
The bolt 18 is inserted into a space 17 formed in both the holder part 5 and the holder part 5, and the shaft part 18b is screwed onto the tip part 18c of the bolt 18 passing through the holder part 5. The inner diameter of this space 17 is approximately the same as the head diameter of the bolt 18, and the height is set to [vertical length of the head 18a + t] so that the head 18a can move a predetermined distance t.

Next, the operation will be explained.

First, the fixed mold 1 and the movable mold 2 are clamped, and the hydraulic cylinder 7 is operated to move the movable core 3 forward. Then, the movable insert 11 comes into contact with the fixed mold 1,
Accurate positioning is achieved by the step portion 8 and the like of the holder portion 5 coming into contact with the movable die 11. As a result, a product cavity 6 is defined as shown in FIG. Molten aluminum alloy is injected into the product cavity 6 from an injection port (not shown). The molten metal injected into the product cavity 6 is cooled by the surrounding mold, solidifies and shrinks, resulting in arrow B in Figure 2.
A clamping force is generated in the direction.

Then, as shown in FIG. 3, after the molten metal has solidified, the hydraulic cylinder 7 is operated to start pulling out the moving core 3. Until the movable core 3 is pulled out a predetermined distance t, the movable core 11 only receives the tightening force due to solidification and contraction of the product 20, and the bolt 18 is not moved at all because the pullout force of the hydraulic cylinder 7 does not act on it. , only the fixed insert 10 overcomes the clamping force of the product 20 and is pulled out a predetermined distance t. Predetermined distance t
After the movement, the head 18a of the bolt 18 is attached to the holder part 5.
Thereafter, the pulling force of the hydraulic cylinder 7 is transmitted to the movable insert 11 via the bolt 18, and the movable insert 11 is differentially engaged with the fixed insert 10 after a delay of a predetermined distance t. After that, they will be extracted together.

At this time, until the movable insert 10 is moved a predetermined distance t, the pull-out force is sufficient to overcome the clamping force against the fixed insert 10, and after the predetermined distance t has been moved, there is almost no resistance on the fixed insert 10 side, so the movable insert It is only necessary to apply a pulling force sufficient to overcome the tightening force against 11. Therefore, compared to the conventional case where force is required to simultaneously overcome the clamping force applied to both the fixed insert 10 and the movable insert 11, the pulling force can be significantly reduced, and the fixed insert 10 and movable insert 11
If you can reduce the tightening force applied to 5 minutes to 5 minutes, the pulling force will be about half of the conventional one.

Even if casting occurs between the inserts, when the fixed insert 10 moves a predetermined distance t relative to the movable insert 11, a space 16 for removing the casting is opened below. As a result, the cast material adhering to the inner circumferential surface of the fixed insert 10 is removed downward through the space 16, and reliable two-stage extraction is possible with a simple structure.

In addition, since the insert part 4 is divided, the movable insert part 11
If it is broken or damaged, it can be quickly replaced.

Moreover, since the insert part 4 is divided, the cooling efficiency of the movable insert 11 is improved compared to the case where the insert part 4 is integrated.

Furthermore, even if galling occurs inside the fixed insert 10, maintenance can be easily performed by removing the movable insert 11.

Although a specific embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and includes various embodiments within the scope of the claims for utility model registration. It is.

For example, in the embodiment, the fixed insert is cylindrical, but it may be rectangular.

[Effect of idea]

From the above, according to the moving core for molds of the present invention,
It has the following effects.

(a) The insert part of the movable insert is divided into a movable insert and a fixed insert, and a differential mechanism is provided between the two, and the sliding surface of the movable insert is made easy to remove the casting. Since the space is provided, the pulling force from the product can be significantly reduced, and reliable two-stage pulling can be performed with a simple structure. As a result, the drawing drive means and mold can be made smaller than before, and
Space can be saved. (b) Since the mold and drawing drive means can be downsized, costs can be significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a state in which a moving core for a mold according to an embodiment of the present invention is attached to a die-casting mold, and Fig. 2 is a diagram of the structure of Fig. 1 showing the state of the moving core immediately after pouring. FIG. 3 is an enlarged sectional view of A section in FIG. 1 showing the state of the moving core during mold release operation;
FIG. 4 is a sectional view showing a conventional moving core. 1...Fixed mold (mold), 2...Movable mold (mold),
3... Moving core, 4... Nesting part, 5... Holder part, 6... Product cavity, 7... Hydraulic cylinder, 8... Step part of holder part, 9... Recessed part of holder part, 10 ...Fixed insert, 11...Movable insert, 12
... Guide hole, 13 ... Mounting member, 14 ... Bolt, 15, 16, 17 ... Space, 18 ... Bolt, 19 ... Molten metal, 20 ... Product, 21 ... Shoulder.

Claims (1)

[Scope of Claim for Utility Model Registration] A moving core that is attached to a mold and can move freely into and out of the product cavity in order to define the product cavity together with the mold, and this moving core comes into direct contact with the molten metal. The nesting part and
The insert part is divided into a fixed insert and a movable insert, and the sliding surface of the movable insert that comes into contact with the fixed insert is partially non-contacted. 1. A movable core for a mold, wherein a space is formed, the fixed insert is integrated with a holder part, and the movable insert is movable a predetermined distance with respect to the holder part.