JPH0157986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a molten metal casting apparatus, particularly to a molten metal casting apparatus for a die casting machine.

[Prior art] In the past, many die casting machines had the mold clamping direction and the injection direction in the same direction, but in recent years, horizontal die casting machines have been developed in which the molten metal is injected from below into a mold that is clamped horizontally. Tightening and vertical casting type die casting machines have been developed.

This type of die casting machine is characterized by the fact that the length of the molten metal in the casting sleeve before injection is short, so that the temperature of the molten metal does not drop much. There are many advantages, such as less mixing and fewer cavities caused by gas in the casting sleeve, and effective pressure transmission due to the injection plunger facing the cavity when filling is completed. Although this method has excellent features, there is a problem in that the molten metal solidified on the side wall surface of the casting sleeve enters the cavity due to the temperature drop during injection, deteriorating the quality of the product.

Therefore, the present applicant proposed a die-casting method and apparatus disclosed in Japanese Patent Publication No. 58-55859 to prevent the intrusion of the coagulated material.

In this device, a halved cylindrical fixed sleeve is fitted into a fixed mold and a movable mold, and the lower end of the fixed sleeve is joined to a casting sleeve rising from below. A plunger that moves forward and backward in the vertical direction is fitted into the casting sleeve by a vertical casting injection cylinder. A small diameter constriction is formed between the mold cavity and the inner hole of the fixed sleeve.

With this structure, when the plunger is moved forward after pouring metal into the casting sleeve in the lowered position and raising it to join with the fixed sleeve, the molten metal in the casting sleeve is fixed. It is cast into the cavity through the inner hole and constriction of the sleeve. Then, the shell, which is a thin cylindrical solidified material formed along the inner circumferential surface of the inner hole of the fixed sleeve during casting, is compressed into a bellows shape between the plunger and the flat surface of the stepped part in front of the constriction part. By doing this, the shell remains in the inner hole of the fixing sleeve and can generally be prevented from entering the cavity. After the casting is completed, the product solidified and taken out from the cavity is accompanied by a so-called biscuit, which is a solid substance left above the plunger, through the solid substance in the constriction, but a thin solid substance corresponding to the constriction is attached to the product. This can be easily removed by folding the object.

[Problems to be Solved by the Invention] However, in such a conventional molten metal casting apparatus, when the casting sleeve and plunger are lowered after completion of casting, the upper end surface of the plunger and the biscuit are in close contact with each other. As a result, the biscuit would stick to the casting sleeve and the solid material would break off from the narrow part corresponding to the constriction, resulting in the product being removed with the biscuit remaining on the casting sleeve side. In particular, in the partial shot method, which aims to obtain good casting conditions by observing the flow state of the molten metal in the cavity during pouring, there is The plunger was lowered at a suitable position where the molten metal had been poured halfway, but in this case, the biscuit was easily broken from the constriction when the plunger was lowered. In particular, when the plunger is stopped midway through the casting sleeve, the length of the portion of the biscuit remaining inside the casting sleeve is almost always longer than the length of the fixed sleeve. was attached to the casting sleeve and descending.

In this way, the biscuit remains on the casting sleeve side, which not only prevents the next pouring, but also
If the injection cylinder is tilted with the biscuit cut at the constriction still protruding from the casting sleeve, the tip of the biscuit protruding from the casting sleeve collides with the lower end notch edge of the stationary plate, making tilting impossible. It turns out. Therefore, the protruding part of the biscuit from the casting sleeve is cut off using gas, and then the casting sleeve is tilted to the molten metal supply position and the plunger is raised to push out the biscuit remaining inside the casting sleeve. It had to be removed, resulting in a problem that significantly reduced work efficiency. In addition, if the biscuit protrudes from the casting sleeve, even if you try to push the biscuit out of the casting sleeve by raising the plunger with the casting sleeve lowered, the tip of the biscuit will not come out because the amount of descent of the casting sleeve is small. Since it hits the lower end plane of the constriction of the fixed mold, the biscuit cannot be removed from the casting sleeve unless it is cut with gas.

In addition, since the inner surface of conventional fixed sleeves was a complete circumferential surface, the area of the shell's reservoir was still insufficient, and in some cases, the shell could enter the mold cavity through the constriction. It was hot too.

In addition, when molten metal is injected using a conventional fixed sleeve whose inner surface is a perfect circumferential surface, when a relatively large solidified layer enters the mold cavity, the cast product It sometimes remained on the surface or inside of the mold, resulting in defective products, or it did not flow, causing the molten metal to not spread sufficiently into the mold cavity.

The main object of the present invention is to provide a molten metal casting apparatus that improves working capacity and allows the production of high-quality cast products by allowing the solidified molten metal to remain in the casting sleeve as much as possible. It is to be.

Another object of the present invention is to provide a molten metal casting apparatus that reduces the size of the molten metal solidified material as much as possible while preventing the molten metal solidified material from entering the cavity.

Still another object of the present invention is to provide a molten metal casting apparatus in which the molten metal solidified can be easily released from the mold.

[Means for Solving the Problems] In order to solve the above problems and achieve the above objects, a molten metal casting apparatus according to the present invention includes a fixed mold and a movable mold. When the mold is clamped horizontally, a small-diameter constriction extending downward from the mold cavity and a large-diameter vertical hole extending further downward from the constriction are formed, and the molten metal is poured from the vertical casting sleeve. This is a molten metal casting device in which the molten metal is poured into the vertical hole, and has a structure in which a convex portion is provided at the upper part of the inner surface of the vertical hole. Here, the inner surface of the vertical hole refers to the inner surface of the fixed sleeve if a fixed sleeve is provided in that part, and if the fixed sleeve is not provided, it refers to the inner surface of a part of the vertical hole in the mold. .

[Function] In the present invention, when performing a casting operation, when the molten metal rises through the vertical hole portion of the fixed sleeve, it rises over the convex portions and passes between the convex portions, and forms a constriction. It is then cast into the mold cavity. In this case, when the solidified layer formed on the outer circumferential surface of the molten metal passes through the protrusions, it hits the protrusions and is broken into small pieces. If the solidified layer becomes small pieces, it remains on the underside of the convex portion and on the ceiling in front of the constriction. Even if the solidified layer passes through the constriction and enters the mold cavity, the solidified layer is a small piece, so it does not adversely affect the flow of the molten metal or the quality of the cast product.

Further, when the plunger is raised to a position slightly below the convex portion and the casting operation is completed, the molten metal remains below the convex portion in the fixed sleeve, and the molten metal solidifies and remains as a biscuit. Then, when the plunger is lowered, the biscuit is prevented from breaking due to the action of the convex portion, and the biscuit always remains in the mold together with the cast product.

[Example] Next, the present invention will be explained in more detail with reference to an example shown in the drawings.

1 to 4 show one embodiment of the molten metal casting apparatus according to the present invention, in which FIG. 1 is an enlarged cross-sectional view of the lower part of the mold, FIG. 2 is a cross-sectional view taken along the - line in FIG. The figure is a longitudinal cross-sectional view of a horizontal mold clamping, vertical casting type die-casting machine embodying the present invention, and FIG. 4 is a cross-sectional view taken along the line -- in FIG. 3.

In the figure, a die casting machine 21 is equipped with a horizontal mold clamping unit 22 and a vertical casting unit 23. 25, and an end platen (not shown) movably fixed to the other end of the machine base 24. A column 26 connects the four corners of the fixed platen 25 and the end platen and is fixed with nuts 27. A movable platen 28 is supported on this column 26 so as to be able to move forward and backward with respect to the fixed platen 25. The movable platen 28 and a mold clamping cylinder (not shown) on the end platen side are connected by a toggle mechanism 29. 30 is fixed plate 2
5, a fixed mold whose movement in the vertical direction is regulated by a key 31, and which is positioned perpendicularly to the plane of the paper by a key 31a provided vertically in the center of the fixed platen 25; 32 is mounted on the movable platen 28; These two molds 30, 3 are movable molds that are mounted and whose movement in the vertical direction is regulated by a key 33.
2 are joined so as to be openable and closable in the horizontal direction with the dividing surface 34 as a boundary. Here, the reason why the vertical key 31a is provided between the fixed platen 25 and the fixed mold 30 at the center of the fixed platen 25 is that it is provided below the dividing surface 34 between the fixed mold 30 and the movable mold 32. This is because the casting sleeve 52 of the vertical casting unit 23 and the center of the fixed mold 30 in the lateral direction can be easily aligned.

Both molds 30 and 32 have a cavity 35 having the same shape as the cast product, and a constriction 36 continuing below the cavity 35.
and a large-diameter vertical hole 37 that continues below and opens downward, separated by the dividing surface 34. At the boundary between the constriction 36 and the vertical hole 37, there is a divided A shell contact surface 38 is formed which is a plane orthogonal to the surface 34. Furthermore, a half-shaped fixing sleeve 39 is fitted into the vertical hole 37 .

For example, as shown in Figures 1 and 2,
Near the upper end of the inner peripheral surface of the fixed sleeve 39, several protrusions 39a are provided around the entire circumference to prevent the rise of the molten metal near the outer periphery and the solidified layer when the fixed sleeve 39 is filled with molten metal. Even if the plunger 47 descends after the solid biscuit is solidified, a portion of the solid biscuit will be caught on the convex portion 39a and will not descend together with the plunger 47.

In this case, the several protrusions 39a provided in the circumferential direction may be not only square protrusions but also round protrusions. Further, the protrusions 39a can be arranged not only in one stage but also in two or three stages in a staggered manner. Further, the convex portion 39a can be not only a convex portion of a ring piece but also a complete ring shape. However, since the protrusion 39a is provided in this device, the plunger tip 47
The advance limit of a is as shown by the two-dot chain line in Figure 1.
It should be located below the convex portion 39a.

The constriction 36 can also be shaped like a truncated pyramid as shown in FIGS. 1 and 2.

40 is a product extrusion device that extrudes the cast product from inside the cavity 35.

A frame 41 of the vertical casting unit 23 is erected in a pit 42 provided below the mold clamp and supports the end of the machine base 24. between 26 and 4
A cast frame 44 connected by support rods 43 is provided close to the bottom surface of the pit 42. 4
Reference numeral 5 denotes an injection cylinder rotatably supported on a cast frame 44, and a plunger 47 is connected to a piston rod 46 via a coupling 48, so that the plunger 47 is raised and lowered by the hydraulic pressure of the injection cylinder 45. It is composed of

The plunger 47 is connected to the casting sleeve 5 of the vertical casting unit 23 which is tilted by a tilting device which will be described later.
The molten metal injected into the cavity 2 is injected into the cavity 35 by rising. plunger 47
The upper end portion has a diameter that is approximately the same as the inner diameter of the casting sleeve 52, and a plunger 47 moves back and forth to form the casting sleeve 5.
2 and a part of the fixed sleeve 39 are integrally formed with a plunger tip 47a that slides inside.
This plunger 47 may be a normal plunger or may be a double plunger consisting of an outer plunger and an inner plunger.

49 is a block supported by fitting a pair of rams 50 implanted in the upper end surface of the injection cylinder 45 into ram holes, and the hole at the lower end engages with the piston rod 46; The block 49 is raised by the pressure oil introduced into the cylinder 51 provided in the block 49, and the piston rod 4
The block 49 is configured to be lowered by the lowering of the block 6.

A fixing sleeve 39 is attached to the upper end surface of the block 49.
A cast sleeve 5 formed into a cylindrical shape with the same center and diameter as
2 is fixed, and when the block 49 is raised by the hydraulic pressure of the cylinder 51, the casting sleeve 52
and fixed sleeve 39 are concentrically pressed together, and as block 49 descends, both sleeves 5
2 and 39 are configured to be separated from each other.

Reference numeral 53 is a tilting cylinder pivotally supported on the frame 41 side, and the working end of its piston rod is pivotally connected to the injection cylinder 45, and when the block 49 is lowered, both sleeves 39,
By operating the tilting cylinder 53 with the parts 52 separated, the entire vertical casting unit 23 is
It is configured to stand up and tilt between the casting position shown in the figure and the inclined pouring position. Reference numeral 54 designates an adjustable stopper that abuts the injection cylinder 45 to limit its rotation toward the casting position.

The casting operation of the die casting machine configured as above will be explained.

When the fixed mold 30 and the movable mold 32 are mounted on the fixed plate 25 and the movable plate 28, respectively, and the piston rod of the mold clamping cylinder (not shown) is advanced, the movable plate 28, which is in the mold opening position, moves to the toggle mechanism 29.
The mold is moved to the illustrated mold clamping position through the mold clamping position, and mold clamping is performed. During this mold clamping, the injection cylinder 45
The piston rod 46 of the cylinder 53 has been lowered to the position shown, and the block 49 has been lowered further than the position shown, and the sleeves 39 and 52 have been separated, so when the piston rod of the tilting cylinder 53 is advanced, it will move vertically. The entire casting unit 23 is tilted, and the casting sleeve 52 is moved outward from the lower part of the stationary platen 25 (the second
(on the right side in the figure). After injecting the molten metal into the casting sleeve 52 by squeezing or the like, the tilting cylinder 53 is operated again to complete the vertical casting unit 2.
3 is vertically erected and pressure oil is fed into the cylinder 51 of the block 49, the block 49 rises and the casting sleeve 52 is concentrically pressed against the lower surface of the fixed sleeve 39.

After this, pressure oil is introduced into the injection cylinder 45 to raise the piston rod 46, and the plunger 47 is raised via the coupling ring 48 to inject the mold 3.
The mold 30,
The molten metal in the casting sleeve 52 is poured into the cavity 35 of the casting sleeve 52. In this case, the molten metal is fixed on the sleeve 3.
9 and rises through between the respective convex portions 39a.
Furthermore, prior to pouring the molten metal, a portion of the molten metal along the inner wall surface of the casting sleeve 52 begins to solidify.
A thin cylindrical solidified product, a so-called shell, is generated. As the injection operation progresses, the upper end of the solidified layer (shell) formed on the inner circumferential surface of the fixed sleeve 39 rises and is stopped and compressed by the lower surface of the convex portion 39a. And here, Ciel breaks and remains in many small pieces. Moreover, a part of the shell goes over the convex part 39a in a broken state and stops against the flat part 38 in front of the constricted part 36. It should be noted that if a small piece of the shell is inserted from the constriction part 36 into the mold cavity 3,
Even if it falls within 5, it will have almost no adverse effect on the quality of the cast product.

Further, during injection, the molten metal is sequentially fed into the cavity 35 through the constriction 36 from the part farthest from the shell, ie, the central part where the temperature is high. When the casting is completed and the molten metal in the cavity 35 is solidified and cooled to form a product, the plunger 47 is first lowered. Then, the pressure oil in the cylinder 51 is removed and the block 49 is lowered to separate the casting sleeve 52 from the fixed sleeve 39. Then, by retracting the piston rod of the mold clamping cylinder, the movable platen 28 is moved to the fixed platen 2.
5, the mold is opened, and the cast product is extruded by the product extrusion device 40, thereby completing one cycle.

Note that when the plunger 47 descends before opening the mold, the upper end surface of the plunger tip 47a and the biscuit 5 formed by the solidification of the molten metal above the plunger tip 47a are removed.
5 are in close contact with each other, and this biscuit 55 is attached to the plunger 4.
7, but the convex portion 39a
As a result of this action, the convex portion 39a is formed in the biscuit 55 so that the biscuit 55 remains on the product side and only the plunger 47 descends.
As a result, the product extruded from the cavity 35 comes with a thin joint corresponding to the constricted portion 26 and the biscuit 55, so that the biscuit 55 can be easily separated from the product by breaking the thin joint with a hammer or the like. .

FIG. 5 shows a protrusion 39 in the middle of the fixed sleeve 39.
3 is a graph showing the relationship between the plunger tip position and load during injection operation for the conventional type without a and the present invention with a convex portion 39a. however,
The plunger tip position S is at the constriction 36 of the mold.
The lower end position of the plunger tip 47a, where the tip of the molten metal contacts the shell contact surface 38, is set to 0, and the upper side is expressed as plus and the lower side is expressed as minus. Moreover, the load T was expressed by the output of the injection cylinder.

As can be seen from FIG. 5, when the fixed sleeve 39 has the convex portion 39a as in the present invention, almost no load is applied to the plunger tip until just before the mold cavity 35 is sufficiently filled with molten metal. However, the load suddenly increases just before filling is completed.
It shows the ideal load curve and filling condition where the molten metal is completely filled and casting is completed.

On the other hand, as in the conventional case, the fixed sleeve 3
If 9 does not have a convex portion 39a, when the molten metal starts to enter the mold cavity 35, the load will gradually start to be applied and the load will increase quickly. Then, the load reaches its maximum value before the plunger tip 47a has been raised to the filling completion position. This indicates that the mold cavity 35 is not sufficiently filled with molten metal. In other words, this indicates that a defective cast product with chipped parts has been produced. This state is thought to be due to the fact that the solidified layer is not sufficiently captured before the constriction 36 and enters the cavity 35 as a relatively large lump, which prevents the smooth flow of the molten metal and the transmission of force.

In this way, when the fixed sleeve 39 is provided with a stepped portion such as the convex portion 39a, the hot water flows well, a large solidified layer does not form, and a cast product of high quality and high strength can be reliably and easily obtained.

[Effect] In this way, in the present invention, the convex portion is provided on the inner peripheral surface of the fixed sleeve in front of the constriction in front of the mold cavity, so that the solidified layer is not captured or broken into small pieces during injection. This makes it possible to suppress the solidified layer from entering the mold cavity as much as possible. Even if the solidified layer enters the mold cavity, the solidified layer is only a small piece, so it will not deteriorate the flow of the molten metal or the quality of the cast product, making it easy to obtain high-quality cast products. be able to.

In addition, at the end of injection, the biscuit part firmly sticks to the inner surface of the fixed sleeve due to the action of the convex part, so when the plunger tip is lowered, the biscuit part sticks to the narrow constriction in front of the mold cavity. It does not break, and subsequent removal of the cast product and biscuit portion can be carried out smoothly and reliably.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a longitudinal cross-sectional view of the sleeve portion of a molten metal casting device, Fig. 2 is a cross-sectional view taken along the line - - of Fig. 1, and Fig. 3 is a cross-sectional view taken along the line - A vertical cross-sectional view of the die-casting machine, Figure 4 is
5 is a diagram showing the relationship between the position of the plunger tip and the load (output of the injection cylinder) during injection with and without a convex portion on the inner surface of the fixed sleeve. 22...Horizontal clamping unit, 23...Vertical casting unit, 30...Fixed mold, 32...Movable mold, 3
5... Mold cavity, 36... Neck part, 37
... Vertical hole portion, 38 ... Shell contact surface, 39 ...
Fixed sleeve, 39a... Convex portion, 47... Plunger, 45... Injection cylinder, 49... Block, 52... Casting sleeve, 53... Tilting cylinder.

Claims (1)

[Claims] 1.Equipped with a fixed mold and a movable mold, when these molds are clamped horizontally, a mold cavity, a small diameter constriction extending downward from this mold cavity, and a large diameter constriction extending further downward from this constriction. A horizontal clamping vertical casting type molten metal casting device having a vertical hole formed therein and allowing the molten metal to be poured from a vertical casting sleeve, the molten metal having a convex portion provided at the upper part of the inner surface of the vertical hole. Casting equipment.