JPH0857620A - Plunger sleeve for die casting - Google Patents

Abstract

PURPOSE: To prevent defective casting operation by preventing the occurrence of trouble in the sliding of a plunger by thinning the thickness of a free end toward the end part so that at least the lower surface of a plunger hole is formed in almost linear-shape. CONSTITUTION: In a sleeve 4 consisting of a cylindrical main body, the plunger hole 15 is penetratingly opened at the center part, a flange 16 for fixing is formed at the front end part, and a molten metal supplying hole 4b is opened at another end side. The sleeve 4 is heated with the heat of molten metal and subjected to the thermal expansion, thereby at least the inner surface of the lower half part of the plunger hole 15 is formed in an inclined curving surface deformed to the reverse direction beforehand from the relation between this thermal expansion and the deformation so as to not to occur the trouble in the movement of the tip of the plunger in the linear-state or the near condition thereof. The part formed with the tapered part 15b inward of the plunger hole 15 is ordinarily the free end part which is not supported to a platen and can be bent in any direction with the thermal expansion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a plunger sleeve used in a die casting machine.

[0002]

2. Description of the Related Art In a die casting apparatus, a platen supports a middle portion of a plunger sleeve (hereinafter simply referred to as a sleeve), and a tip portion of the sleeve is fitted into a fixed die.
A movable mold is abutted against this fixed mold to form a cavity, which is the original form of the cast product, on the mating surface of these molds, and a hot water supply port is opened in the rear portion projecting from the platen, and the molten metal is melted from this hot water supply port. Is supplied, and the molten metal is pressed by a plunger and injection-molded in the cavity. That is, the rear portion of the sleeve where the hot water supply port is opened has a cantilever shape that is not supported by the platen, and is formed as a freely deformable portion.

Aluminum alloy is usually used as a material for die casting, and the molten metal is poured into the hot water supply port of the sleeve, and the plunger waiting near the hot water supply port is introduced into the sleeve to pressurize the molten metal. The mold gate is used to pour hot water into the cavity at high speed. In the die casting process, a molten aluminum alloy is supplied from a hot water supply port of the sleeve at a filling rate of about 50% of the capacity of the sleeve, and this is injected by advancing the plunger. In other words, when hot water is supplied to the inside of the sleeve, the lower part corresponding to about half of the cross-sectional area of this sleeve is filled with molten metal, which is pressed by the plunger to fill the sleeve, and the inside of the cavity of the mold under pressure. It is supposed to be injected into.

Therefore, when the molten metal is supplied, the temperature of the lower half of the sleeve, which is in contact with the molten metal, rises rapidly,
In the cross section of the sleeve, a considerable temperature difference occurs between the upper side surface and the lower side surface. Thus, a difference in thermal expansion between the upper and lower halves of the sleeve causes a difference in thermal expansion, and only the lower half thermally expands more than the upper half and the entire sleeve bends upward in a banana or bimetal shape. It will be. This bend is the largest at the part not constrained by the platen, especially near the hot water inlet.For example, in the case of a die casting machine with a mold clamping force of 1000 tons, the end face immediately after hot water has a large bend of about 1.0 mm to 5.0 mm. Will occur.

When the plunger (piston or tip) is inserted into the upwardly curved U-shaped sleeve like a banana, it is naturally difficult for the plunger (piston or tip) to smoothly slide (causing galling). Depending on the situation, casting work may not be possible. On the other hand, when the sleeve is set in the casting machine, most of it is constrained by the platen, which is a fixture of the casting machine, and the freely deformable part is the part between the hot water inlet and the end face that is not constrained by the platen. Since it is a cantilever-shaped portion and the hot water supply port is a free-supporting portion and is a cavity that cannot resist bending, it is in a more easily deformable state.

[0006]

Since the sleeve made of steel has good heat conduction, the molten metal temperature drops sharply from the contact surface of the inner diameter of the sleeve immediately after the hot water is supplied, and the solidification start temperature (around 575 ° C) is reached in just a few seconds. There is a problem that the solidified phase is partially crystallized by the start of injection, and if this is injected as it is, the flow of molten metal is obstructed.

As a current measure for preventing the sleeve from bending upward, a water cooling jacket is provided at the bottom of the hot water supply port, and cooling water is caused to flow in the jacket so that the temperature difference between the sleeves does not become large. Therefore, the difference in thermal expansion does not occur in the cross section. However, if this cooling method using a water cooling jacket is adopted, it is difficult to maintain the sleeve at a temperature suitable for casting, and the molten metal filled in the sleeve is rapidly cooled. As a result, a part of the molten metal solidifies between the filling of the sleeve with the molten metal and the injection of the molten metal into the mold, resulting in the formation of primary crystals to form a “sorbet-shaped” melt. Will be cast into the mold.

When the molten metal becomes sherbet-like, the fluidity is significantly deteriorated, and in extreme cases, the gate, which is a passage to the cavity, may be blocked. Further, even after passing through the gate, the primary crystal is present inside the structure and becomes a “breaking chill layer”, which reduces the strength and airtightness of the product, or because it is locally hardened, the product is not cured during processing. It causes many problems such as chipping.

As described above, the steel sleeve has a problem that it bends like a banana due to the heat of hot water supply. A ceramic sleeve has been proposed for the purpose of fundamentally improving this problem. However, this sleeve is fragile, has the drawback of being damaged by mishandling, is expensive, and has restrictions in terms of design. Further, as opposed to the method of cooling the sleeve to prevent bending, a method of adopting a “hot sleeve” for heating has been proposed. However, the water-cooled sleeve using tool steel is more difficult to control than the water-cooled sleeve, and satisfactory results have not yet been obtained.

The present invention provides a die-casting sleeve capable of preventing a defective casting operation due to a banana-shaped bending of the sleeve while preventing the formation of a fracture chill layer caused by cooling the prior art sleeve. The purpose is.

[0011]

According to the present invention for achieving the above object, a horizontal casting type die-casting sleeve is formed by penetrating a plunger hole at the center of a cylindrical main body having both ends opened. With the plunger sleeve having a hot water supply port that opens to the plunger hole on the side surface on one end side, a plunger hole formed at the free end not supported by the platen of the die casting machine on the side where the hot water supply port is opened is formed. In order to prevent the sliding of the plunger from being hindered by at least the lower surface of the plunger hole when it is heated by hot water and deformed due to a difference in thermal expansion, the meat of the free end is formed into a straight line. It is composed by deleting it toward the department.

Further, the plunger hole formed at the free end of the horizontal casting type sleeve is formed as a tapered hole whose end side is widened. The tapered hole is formed by expanding from a portion near the die side where the hot water supply port is provided toward the end side. Specifically, regarding the dimensional relationship of the taper hole, the length L of the sleeve body of the die casting machine having a normal mold clamping ability is in the range of (300 to 1500 mm), and the length T of the taper hole is (100 ~ 500 m
m), and the taper of the tapered hole T (thickness of the removed portion of the meat) is (0.
The range is 1 to 5.0 mm).

The plunger sleeve for die casting according to the present invention allows the U-shaped or banana-shaped bending upward of the free end due to the difference in thermal expansion generated in the sleeve due to the temperature difference when the hot water is supplied to the inside thereof. The present invention provides a means for holding the plunger hole formed in the above in a state where it does not hinder the sliding of the plunger. The present invention does not attempt to suppress the deformation by cooling or heating the free end of the lateral casting type sleeve as in the prior art, but is essentially the opposite idea. That is, the sleeve of the present invention is freely deformed under the heat of hot water supply, and in this deformed state, the surface on which the plunger slides is held as straight or straight as possible so that the movement of the plunger is prevented. It is something that should not be done.

Specifically, it is most suitable to adopt a means for expanding the hot water supply port of the plunger hole into a trumpet shape as described above, but if there is no problem in processing, only the lower half is expanded. It is also possible to adopt the above configuration. The sleeve is usually made of tool steel. And, depending on the capability of the casting machine, normally a sleeve with a total length L (300-1500 mm) has a plunger hole (100-500 mm) formed at its free end.
It is preferable to form a tapered surface that widens toward the end in the range of about (mm). And this tapered surface is (100 ~ 50
0 mm) within the range of the length T,
At the end, it is preferable to remove the meat within the thickness range (0.5 to 5.0 mm).

Incidentally, in the present invention, the plunger hole at the free end which is not supported by the platen of the horizontal casting type sleeve eliminates the banana-like deformation of the meat at the portion where it interferes with the sliding of the plunger. Is. And the meaning of the free end means a portion that is deformed by heating by hot water supply.For example, if the portion supported by the platen is also deformed, this portion may be included and meat may be deleted. means.

The amount of meat to be removed is not uniquely determined. That is, the size of the sleeve used, the frequency of hot water supply, the stroke range of the plunger, the state of heat radiation, etc. differ depending on the capacity of the die casting machine, and the meat to be deleted in consideration of the conditions of the individual die casting machine. You must decide the amount of. Further, in the case where the free end of the sleeve is made thicker than a normal one to suppress the bending thereof, the amount of meat to be deleted in the plunger hole can be considerably reduced.

[0017]

[Operation] Expand the plunger hole formed in the free end of the horizontal casting sleeve that is not supported by the platen of the casting machine in the bending direction of this sleeve (expand so that at least the lower surface faces downward). Since it is formed in this way, when the molten metal is supplied to this sleeve, the sleeve bends upward in a banana shape due to thermal expansion, but the plunger hole formed inside due to this bending is straight or straight curved. The plunger can be smoothly slid in the hole by being deformed into a shape.

Particularly, the sleeve of the present invention is based on the premise that at least the lower surface of the plunger hole is linearly deformed by free thermal expansion, and the sleeve is water-cooled and supplied as in the conventional case. Since the molten metal will not be cooled to form primary crystals in a part thereof, it is possible to efficiently produce a high quality die cast product.

[0019]

EXAMPLES Examples of the present invention will be described with reference to the drawings. First, an outline of a die casting apparatus will be described before describing the details of the present invention. FIG. 4 shows a horizontal casting type die casting apparatus 1 in which a platen 3 provided on a bed 2 supports a cylindrical plunger sleeve 4, a fixed mold 5a is provided in front of the platen 3, and a fixed mold 5a is provided in front of the fixed mold 5a. A movable die 5b is supported by a movable platen 6 at a portion thereof, and a plunger 8 driven by a cylinder device 7 is provided at a rear portion of the sleeve 4.
The tip of the plunger 8 is provided with a tip 8a, which is slid in the plunger hole to inject the molten metal.

FIG. 5 shows the details of the vicinity of the sleeve 4, in which the sleeve 4 is supported via an outer sleeve 4a provided on the platen 3, and a fixed die 5 is provided on the front part of the sleeve 4.
The bush 9 fitted to a is connected, and the molten metal is injected into the cavity 10 formed between the fixed die 5a and the movable die 5b, which are already assembled via the bush 9. The sleeve 4 is composed of a fixed portion (a) supported by the platen 3 and a free end portion (b) protruding from the platen 3.

Then, a predetermined amount of molten metal such as aluminum alloy melted in a melting furnace (not shown) is supplied from a hot water supply port 4b provided at the rear portion of the sleeve 4, and the cylinder device 7 is driven to tip the tip 8a of the plunger 8. The molten metal supplied into the sleeve 4 is pressurized and injected. Next, details of the structure of the sleeve 4 will be described.

FIG. 1 is a cross sectional view of the sleeve 4, FIG. 2 is a side view of the hot water supply port side, and FIG. 3 is a plan view of the hot water supply port portion. The sleeve 4 is composed of a cylindrical main body, a plunger hole 15 is opened through the center of the sleeve 4, a fixing flange 16 is formed at the tip, and a hot water supply port 4b is opened at the other end.

The plunger hole 15 has a parallel portion 15
a and a tapered portion 15b.
A hot water supply port 4b is arranged above b. The tapered portion 15b is a portion corresponding to the free end portion (b) in FIG. By deforming at least the lower surface of 15 linearly, the tip 8a of the tip portion of the plunger 8 is formed.
To smoothly move in the plunger hole 4.

Therefore, the sleeve 4 according to the present invention is heated by the heat of the molten metal and its part is thermally expanded. As a result, the inner surface of at least the lower half of the plunger hole 15 is linear or close to the inner surface of the plunger 8 (FIG. 4). In view of the relationship between the thermal expansion and the deformation, the tip 8a is formed into an inclined curved surface that is deformed in the opposite direction in advance so as not to hinder the movement of the chip 8a.

The portion where the tapered portion 15b is formed is a free end portion (b) which is not normally supported by the platen 3 and can be bent in any direction by thermal expansion. In the state where the molten metal is supplied as described above and the sleeve 4 is deformed due to thermal expansion, at least the surface of the sleeve 4 into which the plunger 8 enters should be formed to be a flat surface. Even the one formed on the inclined curved surface can be sufficiently used. However, it is preferable to form a taper-shaped or trumpet-shaped hole as shown in FIGS. 1 to 3 for the purpose of performing accurate processing and accurate deformation in a heated state.

Next, the dimensional relationship of the portion where the tapered portion 15b is formed will be explained.
The total length L of the sleeve 4 used in the die casting machine of the ton to 3500 ton class is in the range of 300 to 1500 mm, and the length T of the tapered portion 15b is 100 to 500 mm, preferably 1
It is in the range of 50 to 300 mm. And the tapered portion 15
Judging from a number of experiments conducted by the present inventors, the taper of b has a length T = 100 to 300 mm, the taper between them is D−d = 0.2 to 10.0 mm (0.1 to 5.0 m in thickness).
The range is m).

Therefore, it seems that the clearance between the end of the sleeve 4 at room temperature (corresponding to the free end (b) in FIG. 5) and the tip 8a is about 0.3 to 0.5 mm. When the sleeve 4 configured as described above is attached to the die casting apparatus 1 shown in FIG. 4 to perform a casting operation, as long as the molten metal is not supplied into the sleeve 4, as shown in FIG. Is a straight line state, and the surface of the plunger hole 15 on which the tip 8a slides is not a straight line.

When the molten metal is supplied into the sleeve 4, the lower side surface H of the sleeve 4 of FIGS. 1 and 2 receives the heat of the molten metal and bends upward in U as shown by the chain line in FIG. . By thus bending in an arc shape, the inner surface of the lower half of the parallel portion 15a and the inner surface of the lower half of the tapered portion 15b become substantially linear. That is, the inner surface of the lower half of the plunger hole 15 which is bent downward in the unheated state is straightened or flattened in the heated state so that the sliding of the tip 8a is corrected.

As described above, when the sleeve 4 is bent to the upper side U, the upper surface side of the taper portion 15b is inclined further upward, but as shown in FIG. 4, the tip of the plunger 8 driven by the cylinder device 7 is used. On the contrary, the lower half surface on which the tip 8a of the above slides is held substantially flat. Therefore, the tip 8a can be smoothly moved in the plunger hole 15 formed by the continuous surface of the parallel portion 15a and the tapered portion 15b whose lower half is corrected to be flat.
Then, the molten metal supplied into the tapered portion 15b is fed to the parallel portion 1
5b is rapidly pressurized to fill the cavity 10 between the molds 5a and 5b at a high speed. When the filled melt is cooled and solidified, the movable mold 5
The b is separated from the fixed die 5a to take out the die cast product.

Next, the structure of the plunger sleeve 4 according to the present invention will be further described. FIG. 6 shows a cross-sectional view and a cross-sectional view taken along the line XX of the plunger sleeve 4 in which the inner surface of the plunger hole 15 below the hot water inlet 4b is deleted in a semi-circular shape as shown by the diagonal lines to form a deleted portion 17. There is. Since the sleeve 4 of this embodiment is made thin by removing a small amount of meat in the lower half which the hot water supply port 4b faces, there is no problem in terms of strength.

FIG. 7 corresponds to the sleeve 4 shown in FIGS. 1 to 3, and a tapered portion 1 is formed by forming a deletion portion 17 in a tapered shape on the inner surface of the plunger hole 15 near the hot water supply port 4b.
5b shows a cross-sectional view and a side view of the sleeve 4 as 5b. In this embodiment, the inner side of the hot water supply port 4b of the sleeve 4 is made thickest and the rearward widened taper shape is removed. This structure is excellent in that it can be easily and accurately machined with a lathe or the like.

As described above, the original shape of the sleeve 4 is manufactured into a cylindrical shape, and thereafter, the deletion portion 17 is formed according to the usage state of the die casting apparatus 1 in which the sleeve 4 is used, and the parallel portion 15a is formed at room temperature. When the rear side, that is, the end side is expanded or inclined to form the tapered portion 15b, or the lower surface is deleted to be an inclined surface, and the sleeve 4 is deformed into a banana shape by increasing the operating temperature. At least the lower surface allows the tip 8a of the plunger 8 to slide. Therefore,
The present invention can be modified not only in the above-described embodiment but also in the scope of the technical formula idea.

[0033]

The plunger sleeve 4 for die casting according to the present invention has a cylindrical body whose both ends are open, which penetrates the plunger hole at the center of the main body, and has a hot water supply port which opens to the plunger hole on the side surface on one end side. In the plunger sleeve, the plunger hole formed at the free end that is not supported by the platen of the die casting apparatus on the side where the hot water supply port is opened is heated by hot water and deformed by the difference in thermal expansion, In order that at least the lower surface of the plunger hole does not interfere with the sliding of the plunger, the meat of the free end is deleted toward the end so as to be substantially linear.

Since the die 4 is cast while the sleeve 4 is deformed and the tip 8a at the tip of the plunger 8 is automatically corrected, the tip 8a at the tip of the plunger 8 is fixed to the sleeve 4. It is possible to perform die casting by sliding smoothly without being caught on the inner surface of the die. As described above, according to the present invention, since it is not necessary to locally cool the sleeve 4 with the cooling water, when the molten metal is supplied to the sleeve 4, the molten metal is not rapidly cooled, and a primary crystal accompanying cooling is melted. Since the generation can be prevented, the molten metal is filled in the mold in a preferable state without changing into a sherbet shape.

Therefore, the flow of hot water is not obstructed,
Further, the gate is not closed, and various problems such as strength reduction and airtightness reduction of the die-cast product and chipping during processing can be solved at once.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a plunger sleeve.

FIG. 2 is a right side view of a plunger sleeve.

FIG. 3 is a plan view of a hot water supply port portion.

FIG. 4 is a diagram showing an outline of a die casting apparatus.

FIG. 5 is a cross-sectional view showing around a plunger sleeve.

6A and 6B are a lateral cross-sectional view and a XX cross-sectional view of the plunger sleeve.

7A and 7B are a lateral cross-sectional view and a right side view of another plunger sleeve.

[Description of sign]

1 Die casting machine 2 Bed 3 Platen 4 Plunger sleeve 4a Outer sleeve
4b Hot water supply port 5a Fixed type 5b Movable type 6 Moving platen 7 Cylinder device 8 Plunger 8a Chip 10 Cavity 15 Plunger hole 15a
Parallel part 15b Tapered part 16 Fixing flange

Claims (4)

[Claims] 1. A plunger sleeve having a cylindrical main body having both ends opened, which penetrates a plunger hole at the center of the main body and has a hot water supply port communicating with the plunger hole on a side surface on one end side, wherein the hot water supply port is opened. When the plunger hole formed at the free end not supported by the platen of the die casting machine on the holding side is heated by hot water and deformed due to the difference in thermal expansion, at least the lower surface of the plunger hole slides on the plunger. A plunger sleeve for die casting, in which the meat of the free end is removed toward the end so as to be substantially straight so as not to cause trouble in the above. 2. A hot water supply port that opens through the plunger hole at the center of a cylindrical main body with both ends open and has a side surface on one end side that communicates with the plunger hole, and the hot water supply port is opened. Plunger sleeve for die casting, in which the portion of the plunger hole that is not supported by the platen of the die casting machine on the existing side is formed into a tapered hole that widens toward the end side. 3. The plunger sleeve for die casting according to claim 2, wherein the tapered hole is formed between the vicinity of the portion where the hot water supply port is open and the end portion. 4. The length L of the main body is 300 to 1500 mm, the length T of the tapered hole is 100 to 500 mm, and the taper of the tapered hole T is at the end of the plunger sleeve.
The plunger sleeve for die casting according to claim 2, which has a diameter of 0.1 to 5.0 mm.