JPH06312252A - Structure of die in casting apparatus - Google Patents

Abstract

PURPOSE:To obtain a structure of a casting die for aluminum product, by which the entrapment of gas in molten metal is prevented and the development of blow hole can efficiently be prevented and molten metal cunning condition is made to be good because the heat retaining property at the necessary position is improved. CONSTITUTION:The structure of the die in the casting apparatus is composed of a fixing die and plural divided movable dies and the molten metal is filled into a cavity formed in the die in the clamping condition to form the prescribed shape of cast product. Then, at the upper part of a sliding-contact surface 2a of the movable die 2 slidingly contacting with the movable dies 2, 5, one or more of molten metal pouring basin parts 10 are formed. A molten metal passage communicated from the cavity 3 to the pouring basin part 10 is arranged in the movable die 2 (or 5). A gas vent 11 for discharging the gas in the cavity from the pouring basin 10 is formed in the movable die 5 (or 2) at the almost same width as the width of the pouring basin part 10 and extremely shallow depth in comparison with the depth of the pouring basin part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die structure of a casting apparatus for injecting a molten metal or the like into a cavity formed in a die to form a cast product having a predetermined shape, and more particularly to an automobile engine. When injection-molding a large-sized and relatively complex shape casting product such as a cylinder block, it is necessary to improve the gas release from the cavity and to spread the molten metal well throughout the cavity. The present invention relates to a mold structure of a casting apparatus capable of effectively preventing the occurrence of defects and defective molding.

[0002]

2. Description of the Related Art A mold of a casting machine (die casting machine) for injection-molding a large-sized and relatively complicated casting product, such as a cylinder block of an automobile engine, has a fixed metal mold fixed to the body of the casting machine. It is generally composed of a mold and a movable mold which is divided into a plurality of parts so that the cast product can be easily taken out of the mold and which can be moved back and forth with respect to the fixed mold. Then, the molten metal is injected into the cavity formed in the mold in a mold clamped state at a high pressure from a spout provided in the fixed mold, left to cool for a predetermined time, and then cooled to open the mold into a predetermined shape. The cast product is taken out.

By the way, when a large cast product having a relatively complicated shape such as a cylinder block is injection-molded, there is a problem that the molten metal entrains the gas in the cavity to easily form a cavity in the cast product. Further, the molten metal injected into the cavity is cooled by the mold to lower the temperature of the molten metal and deteriorate the molten metal around, but this deterioration of the molten metal causes defective molding and generation of cavities.

In order to solve such a problem, a gas vent for discharging the gas in the cavity to the atmosphere is provided at a position as far as possible from the gate, and the molten metal in the cavity flows smoothly in one direction from the gate side. You can do it like this. Since the sprue is generally provided below the fixed die, it is desirable to provide the gas vent above the movable die sufficiently separated from the sprue. However, due to the structure of the mold, if a gas vent is provided on the sliding surface of the movable mold where the movable molds slide against each other, the metal that has penetrated into the gas vent and solidified adheres to the sliding surface and the mold opening or mold clamping is prevented. In that case, there is an inconvenience that it causes galling. Therefore, the gas vent is currently provided in the fixed mold, and the above-mentioned problems have not been sufficiently solved in injection molding of a particularly large and complicated cast product such as a cylinder block.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and makes it possible to provide a gas vent for degassing in a movable mold sufficiently separated from the sprue, and Casting in which cavities and molding defects are less likely to occur by preventing molten gas from being entrained by allowing the molten metal to flow in a certain direction from the sprue to the gas vent, and allowing the molten metal to spread well throughout the cavity. It is intended to obtain a mold structure for the device.

[0006]

In order to solve the above-mentioned problems, the mold structure of the casting apparatus of the present invention comprises a fixed mold and a movable mold divided into a plurality of parts, which are clamped in In a mold structure of a casting apparatus for injecting a molten metal into a cavity formed in the mold to mold a cast product having a predetermined shape, the movable contact surfaces of the movable molds are in contact with each other. A molten metal passage formed in a sliding contact surface of the movable mold with a plurality of molten metal pools provided so as to communicate the cavity with the molten metal pool to guide molten metal from the cavity to the molten metal pool. And a gas vent that is formed in a slit shape in the vertical direction of the sliding contact surface and communicates with the hot water pool portion to release the gas in the cavity into the atmosphere, and the depth of the gas vent is the hot water pool. Extremely shallow compared to the depth of the part The width of the gas vent with forming characterized by being formed by approximating the width of the hot water reservoir.

[0007]

Since the present invention is constructed as described above, it operates as follows. With the molten metal injected into the cavity of the mold from the gate in the mold clamped state, the gas in the cavity is released into the atmosphere from the gas vents provided.
The molten metal in the cavity flows in a fixed direction from the gate toward the gas vent. A part of the molten metal flows into the molten metal pool formed in the movable mold, but the molten metal that has flowed into the molten metal pool warms the movable mold, so cooling around the molten metal causes deterioration of the molten metal surroundings. It will be kept low and the molten metal will be spread all over the cavity. Therefore, it is possible to effectively prevent the generation of cavities and defective molding due to the entrainment of the gas remaining in the cavity and the deterioration of the bathing area.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described in detail with reference to the drawings. 1 and 2 relate to an embodiment in which the present invention is applied to a cold chamber type die casting machine (casting apparatus). FIG. 1 is a sectional view showing a mold clamping state, FIG. 2 is a sectional view showing a mold opening state, FIG. 3 is a plan view of a cylinder block of an automobile engine injection-molded in this embodiment, and FIG. 4 is an enlarged cross-sectional view of a molten metal pool. As shown in FIGS. 1 and 2, the movable mold 2 that moves back and forth with respect to the fixed mold _{1 in} the direction of the arrow X _{1 in} FIG.
2 has an upper movable mold 5 and a lower movable mold 7 which are slidable along the movable mold 2 in the vertical directions of arrows X ₂ and X _{3 in} FIG. It is easy to take out from the mold. Then, the fixed mold 1 and the movable mold 2 in the mold clamping state (state of FIG. 1).
A cavity 3 for forming the cylinder block W is formed in a portion surrounded by the upper movable mold 5 and the lower movable mold 7. A molten metal such as an aluminum alloy is pressurized by a plunger rod (not shown) and is injected into the cavity 3 at a high pressure from a spout 8 formed below the fixed mold 1.

A molten metal pool portion 10 communicating with the cavity 3 for storing overflowed molten metal is orthogonal to the plane of FIG. 1 at an appropriate interval on the sliding contact surface 2a of the movable mold 2 which is in sliding contact with the upper movable mold 5. Five of them are arranged and formed in the direction. As shown in FIG. 4, the molten metal pool 10 has a tapered cross section so that the molten metal solidified in the molten metal pool 10 can be easily removed from the mold together with the cylinder block W.

Next, the position where the basin 10 is provided will be described with reference to FIG. In FIG. 3, reference numeral 15 denotes a cylinder head mounting surface on which the cylinder head is mounted, and 16
Is a cylinder, and reference numerals 10 'and 11' are overflows that have penetrated into the molten metal pool portion 10 and the gas vent 11 and solidified. Although the position where the pool 10 is provided depends on the shape and size of the cylinder block W to be molded, in this embodiment, the vicinity of both ends of the cylinder head mounting surface 15 of the cylinder block W and the cylinders 16 and 16 are provided.
..Provided at a position corresponding to the space. Although the molten metal pool 10 is communicated with the cavity 3 by the molten metal passage 12 formed in the movable mold 2, it should be provided at a position as close as possible to the cavity 3 in consideration of the heat retaining property of the upper movable mold 5. Is desirable.

A slit-shaped gas vent 11 for releasing the gas in the cavity 3 to the atmosphere is provided on the sliding surface 2a of the movable mold 2 with the upper movable mold 5. The gas vent 11 is formed to be as shallow as possible than the depth of the basin 10 so that the molten metal poured into the basin 10 does not easily enter the gas vent 11, and its cross-sectional area is made as large as possible. In order to be able to be taken, it is formed to have a width dimension close to the width dimension of the pool 10.

On the other hand, the molten metal passage 12 quickly pours the molten metal in the cavity 3 into the molten metal pool 10, and the metal solidified in the molten metal pool 10 does not fall off when the mold is opened. In order to be taken out of the mold together with W, it is formed to have a certain width and depth. The molten metal passage 12 is formed in a substantially fan shape so that the molten metal can smoothly flow from the cavity into the molten metal pool 10. In addition, the applicant of the present application is shown in FIG.
In injection molding of the cylinder block W as shown in
As shown in FIG. 4, the depth dimension A of the gas vent 11 is 0.
When the depth dimension B of the molten metal passage 12 was set to 15 mm and the depth dimension B was set to about 2 mm, the amount of the molten metal entering the gas vent 11 could be reduced and good results could be obtained.

The operation of the mold structure of this embodiment having the above-described structure will be described. When a plunger rod (not shown) is advanced in the mold clamping state to inject the molten metal into the cavity 3 through the sprue 8, the gas in the cavity 3 is released into the atmosphere through the gas vent 11. As a result, the molten metal is
It flows in the inside in a fixed direction from the gate 8 side toward the gas vent 11. That is, in the molding of the cylinder block W shown in FIG. 3, the molten metal flows from the lower right side of the paper of FIG. 3 where the gate 8 is provided to the upper left side of the paper.

However, since the molten metal is cooled by the mold as it moves away from the sprue 8 and the flow at the tip of the molten metal (circulation around the molten metal) becomes worse than the flow of the molten metal near the spout 8, a part of the molten metal will reach the spout 8. It will flow into the pool 10 on the near side. When the molten metal flows into the molten metal pool 10, the molten metal in the molten metal pool 10 warms the upper movable mold 5, so that it is possible to prevent deterioration of the molten metal surroundings due to a rapid temperature drop of the molten metal. Therefore, the molten metal can be rapidly spread in the cavity 3, and the amount of the molten metal that enters the gas vent 11 from the molten metal pool 10 can be reduced.

After the injection of the molten metal is completed, the molten metal in the cavity 3 is cooled and solidified by leaving it in the mold clamped state for a predetermined time.
Thereafter, the movable mold 2 is moved to open the mold, and then the driving bodies 4 and 6 are driven to slide and separate the vertically movable molds 5 and 7 along the movable mold 2. The injection-molded cylinder block W includes a push rod 13 fitted on the stat pin 9.
Easily released from the mold by advancing. At this time, the overflow 11 'that has penetrated into the gas vent 11 and solidified is also released from the mold together with the cylinder block W and the overflow 10', so that the overflow 11 'does not remain on the sliding surface 5a and the upper movable mold is kept. No galling will occur during sliding of No. 5. By the above procedure, the cylinder block W separated from the mold is gripped by a transfer device (not shown) such as a robot and transferred to the next step.

Although the preferred embodiments of the present invention have been described, the present invention is in no way limited to the embodiments described above. For example, although the gas vent 11 is provided on the sliding surface 2a of the movable mold 2 in the above-described embodiment, it may be provided on the sliding surface 5a of the upper movable mold 5.

[0017]

Since the present invention is constructed as described above, it becomes possible to provide a gas vent at a position sufficiently distant from the sprue of the movable mold, and the following effects can be obtained. The molten metal injected into the cavity releases the gas in the cavity into the atmosphere through a plurality of gas vents provided, so that the molten metal can flow in a fixed direction from the sprue toward the gas vent, and the gas is not released. Since this can be performed efficiently, it is possible to effectively prevent the formation of cavities due to the entrainment of gas. Further, since the molten metal flows into the molten metal pool portion provided in the movable mold to heat the movable mold, it is possible to suppress deterioration of the molten metal around due to being cooled by the mold, and to reduce the entire cavity. It is possible to spread the molten metal and prevent the formation of cavities and defective molding. Therefore, according to the present invention, in the case of injection-molding a large-sized and relatively complex-shaped cast product, it is possible to reduce the defective rate by reducing defective products such as cavities and molding defects, and significantly reduce the manufacturing cost. Can be expected to be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mold according to an embodiment of the present invention, showing a mold clamped state.

FIG. 2 is a cross-sectional view of a mold according to an embodiment of the present invention showing a mold open state.

FIG. 3 is a plan view of a cylinder block injection-molded in this embodiment.

FIG. 4 is a cross-sectional view illustrating details of a basin and a gas vent.

[Explanation of symbols]

 1 Fixed mold 2 Movable mold 3 Cavity 4,6 Driver 5 Upper movable mold 7 Lower movable mold 8 Gate 10 Hot water pool 11 Gas vent 10 ', 11' Overflow 12 Molten metal passage 13 Push rod W Cylinder block

Claims (1)

[Claims] 1. A casting comprising a fixed die and a movable die divided into a plurality of pieces, and injecting a molten metal into a cavity formed in the die in a clamped state to form a cast product having a predetermined shape. In the mold structure of the apparatus, a plurality of molten metal pool portions provided on the sliding contact surface of the movable mold, which are in sliding contact with each other between the divided movable molds, are formed on the sliding contact surface of the movable mold, A molten metal passage for guiding the molten metal from the cavity to the molten metal pool by making the cavity and the molten metal pool communicate with each other; and a slit-like shape formed in the vertical direction of the sliding contact surface to communicate with the molten metal pool. It consists of a gas vent for releasing the gas in the cavity into the atmosphere, and the depth of the gas vent is formed to be extremely shallow as compared with the depth of the hot water pool, and the width of the gas vent is the width of the hot water pool. Formed to approximate Mold structure of the casting device, characterized in that.