JP3352277B2 - Deformation control method of plunger sleeve for die casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A steel plunger sleeve (hereinafter simply referred to as a sleeve) is used in a die casting apparatus, a platen supports an intermediate portion of the sleeve, and a tip of the sleeve is fitted into a fixed mold. Then, a movable mold is abutted against the fixed mold to form a cavity, which is the original form of a casting, on the mating surface of these molds. Further, a hot water supply port is opened at a rear upper portion of the sleeve protruding from the platen, the molten metal is supplied from the hot water supply port, and the molten metal is pressed by a plunger to be injected into the cavity. In other words, the rear part 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 part that can be freely deformed.

[0003] Aluminum alloy is usually used as a material for die casting, and the molten metal is injected into a hot water supply port of a sleeve, and a plunger waiting near the hot water supply port enters the sleeve to pressurize the molten metal. High-speed pouring into the cavity through the mold gate. In the die casting step, 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 is injected by moving a plunger forward. In other words, when the hot water is supplied into the sleeve, the lower half of the cross-sectional area of the sleeve is filled with the molten metal, which is pressed by the plunger to fill the sleeve, and then injected into the cavity of the mold. It is supposed to be.

Accordingly, when the molten metal is supplied, the lower half of the sleeve in contact with the molten metal rapidly rises in temperature,
In the cross section of the sleeve, there will be a considerable temperature difference between the upper half and the lower half. In this way, a difference in thermal expansion occurs due to the temperature difference between the upper half and the lower half of the sleeve, and only the lower half thermally expands more than the upper half, and the entire sleeve rises in a banana or bimetallic shape. You will bend to This bend is largest at the free part not restrained by the platen, especially near the hot water supply port. For example, in the sleeve of a die casting device of 1000 ton class with a mold clamping force, the end face immediately after hot water supply is as large as about 1.0 mm to 5.0 mm. Bending will occur.

When the plunger (piston or tip) enters the sleeve curved upward in a banana-like U-shape, it is naturally difficult for the plunger to slide smoothly (galling occurs). In this case, the plunger is fixed and casting cannot be performed. On the other hand, when the sleeve is set in the casting device, most of the sleeve is restrained by the platen which is a fixture of the casting device,
The part that can be freely deformed is a cantilever-shaped part between the hot water inlet that is not restrained by the platen and the rear end face, and because the hot water inlet is a cavity that can not resist bending,
It is more easily deformed.

[0006]

As a current countermeasure for preventing the sleeve from being bent upward, a water cooling jacket is provided on a lower surface of the sleeve which is below the sleeve hot water supply port, and a cooling jacket is provided in the jacket. Water is allowed to flow so that the temperature difference of the sleeve does not increase so that a 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 during the period from filling of the molten metal into the sleeve until injection into the mold, and primary crystals are generated to form a "sherbet-like". Is cast into a mold.

When the molten metal is in a sherbet shape, the fluidity is remarkably deteriorated and the flow of the molten metal is hindered. In an extreme case, a gate which is a passage to a cavity may be closed. Further, even after passing through the gate, the primary crystal is present inside the structure, and as a “fractured chill layer”, the strength and the airtightness of the product are reduced, or the product is extremely hardened, so that the product is not processed during processing. It has caused many problems such as chipping.

As described above, the steel sleeve has a problem that a banana-like bending is caused by the heat of hot water supply, and a ceramic sleeve has been proposed for the purpose of fundamentally improving this problem. However, this sleeve is fragile, has a drawback that it is damaged by improper handling, is expensive, and has restrictions in terms of design. In addition, a method has been proposed which employs a “hot sleeve” for heating, contrary to the method of cooling the sleeve to prevent bending. However, anhydrous cooling sleeves using tool steel are more difficult to control than the water-cooled sleeves, and satisfactory results have not yet been obtained.

The present invention provides a method for controlling the deformation of a sleeve for die casting, which can prevent a casting operation defect due to a banana-like bending of the sleeve while preventing the formation of a broken chill layer caused by cooling the sleeve of the prior art. The purpose is to provide.

[0011]

According to the present invention, there is provided a method for controlling the deformation of a plunger sleeve for die casting, wherein the plunger is opened through the center of a cylindrical main body having both open ends. In addition, in a plunger sleeve having a hot water supply port opened to the plunger hole on one side surface, the upper half of a free-end side sleeve body that is not supported by a platen of the die casting device on the side where the hot water port is open is provided. Tei is provided an apparatus for heating insulation
You .

And a bending detecting device for detecting a displacement amount of the free end with respect to a free end of the sleeve main body,
It is configured to adjust the temperature difference between the upper half and lower half of the sleeve body.

[0013] The above-mentioned plastic is attached to the upper half of the sleeve body.
One or more holes are provided along the
There is a method of providing a device for heating and keeping heat . Furthermore, there is a method of providing fins on the side of the lower half of the sleeve body.

[0014]

According to the method of controlling the deformation of the die-casting plunger sleeve configured as described above, the temperature difference between the upper half and the lower half of the sleeve main body is mainly suppressed to a certain range, thereby increasing the sleeve upward. As the plunger hole is prevented from deforming,
The tip can move smoothly in the plunger hole.

Further, the use of the fins alleviates a sudden rise in the temperature of the lower half of the sleeve body to some extent, and makes it easier to keep the temperature difference between the upper half and the lower half of the body within a certain range. It is to be. Further, in the present invention, since the sleeve does not need to be locally cooled by the cooling water, the molten metal is not rapidly cooled when supplied to the sleeve, so that the generation of primary crystals due to the cooling 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 hindered,
Further, the gate is not closed, and various problems such as a decrease in strength and airtightness of the die cast product and a chip during processing can be solved at once.

[0017]

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

FIG. 6 shows details of the vicinity of the sleeve 4. The sleeve 4 is supported via an outer sleeve 4 a provided on the platen 3, and a fixed mold 5 is attached to the front of the sleeve 4.
The bush 9 fitted to the a is connected, and the molten metal is injected into the cavity 10 formed between the fixed mold 5a and the movable mold 5b which have already joined through the bush 9. . The sleeve 4 has a fixed portion (a) supported by the platen 3 and a free end portion (b) protruding from the platen 3.

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 a rear portion of the sleeve 4, and the tip of the tip 8a of the plunger 8 is driven by driving the cylinder device 7. Pressurizes and injects the molten metal supplied into the sleeve 4 (plunger hole). Next, the deformation control method of the sleeve 4 will be described in detail.

FIG. 1 is a longitudinal sectional view of the sleeve 4, and FIG. 2 is a right side view of the sleeve 4. The sleeve 4 is formed of a cylindrical main body. A plunger hole 11 is opened at the center of the sleeve 4, a fixing flange 12 is formed at the tip, and a hot water supply port 4 b is opened at the other end. A plurality of holes 13 are formed at predetermined intervals along the plunger hole 11 in the upper half on the free end side of the sleeve 4 body, and a heating and heat insulating device 14 is set in the hole 13, and a temperature control device (not shown) Connected to Further, plunger holes 11 are provided at the uppermost and lowermost central portions on the free end side of the sleeve 4 body.
A thermometer 16 is set in the small hole 15 and connected to a temperature control device (not shown).

In the state where the molten metal is supplied as described above, the lower half of the sleeve 4 main body is in contact with the molten metal, so that the lower half of the sleeve 4 main body that is in contact with the molten metal rapidly rises in temperature. On the other hand, the temperature of the upper half of the sleeve 4 body that is not in contact with the molten metal does not rise so much, so that a temperature difference occurs between the upper half and the lower half. The temperature difference between the upper half and the lower half of the sleeve 4 is sensed by a temperature control device through a thermometer 15 provided in the main body. Heat half and raise its temperature.
In this way, the heating and heat retaining device 14 is controlled so that the temperature difference between the upper half and the lower half of the sleeve 4 main body is kept within a certain range, thereby preventing the sleeve 4 from being bent.

In another embodiment of the present invention, as shown in FIG.
Is provided, a bend detecting device 18 for the sleeve 4 body is provided. The detection device 18 is connected to a temperature control device (not shown). The temperature control device operates the heating and heat retaining device 14 in accordance with the degree of upward curvature of the sleeve 4 under a preset condition, and causes the upper half of the sleeve 4 main body to operate. Heating is used to raise the temperature, reducing the temperature difference between the upper and lower halves of the body to reduce bowing.

Further, in another embodiment of the present invention, as shown in FIG. 4, a plurality of fins 17 are provided on the side of the lower half of the sleeve 4 main body. The radiation of heat from the lower half of the sleeve main body 4 is appropriately promoted by the fins 17. Therefore, when the temperature control and the deformation control of the sleeve 4 are performed together, the temperature control and the deformation control are performed more efficiently. In addition to simplicity, there is an effect that energy required for temperature control and deformation control is reduced.

As described above, the heat distribution balance of the main body of the sleeve 4 is improved, and the upward bending of the sleeve 4 is prevented or suppressed. Therefore, the deformation of the plunger hole 11 at the center of the sleeve 4 is prevented, and the straight state is maintained, so that the tip 8a can move smoothly in the plunger hole 11.

[0025]

According to the method for controlling the deformation of the plunger sleeve 4 for die casting according to the present invention having the above-described structure, the degree of displacement of the free end of the sleeve 4 main body, that is, the sleeve 4
The upward bending of the main body is detected by the bending detecting device 18,
The heating / heating device 14 is placed on the sleeve 4 body according to the degree of curvature.
Heat the side halves to raise the temperature, upper half and lower half
Since the temperature difference between the plunger 11 and the plunger hole 11 is prevented, the upward bending of the sleeve 4 is suppressed and the deformation of the plunger hole 11 is prevented.
This makes it possible to ensure that the tip 8a moves smoothly in the plunger hole 11.

When the fins 17 are used as described above, the radiation of heat from the lower half of the sleeve body 4 is appropriately promoted, so that the temperature control and the deformation control of the sleeve 4 are performed together. Has an effect of moderately mitigating a sharp rise in the temperature of the lower half of the sleeve main body, facilitating temperature control and deformation control of the sleeve 4, and reducing energy required for the temperature control and deformation control. .

Further, according to the present invention, since the sleeve 4 body is appropriately cooled by air cooling and is not rapidly cooled by cooling water, when the molten metal is supplied to the sleeve 4, it is not cooled rapidly. Since the generation of primary crystals due to cooling can be prevented, this molten metal is filled in a mold in a preferable state without changing into a sherbet shape. Therefore, various problems such as a decrease in the strength and airtightness of the die-cast product, and a lack of processing at the same time, are not caused at all without obstructing the flow of the molten metal, and without closing the gate. That can be solved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a plunger sleeve of an embodiment.

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

FIG. 3 is a longitudinal sectional view of a plunger sleeve according to another embodiment.

FIG. 4 is a front view of a free end side of a plunger sleeve according to another embodiment.

FIG. 5 is a view schematically showing a die casting apparatus.

FIG. 6 is a vertical cross-sectional view showing the periphery of a plunger sleeve.

[Description of sign]

DESCRIPTION OF SYMBOLS 1 Die casting apparatus 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 Tip 10 Cavity 11 Plunger hole 12
Fixing flange 13 Hole 14 Heat insulation device 15 Small hole 16 Thermometer 17 Fin 18 Bend detection device

Claims (3)

(57) [Claims] 1. A plunger sleeve which is opened through a plunger hole at the center of a cylindrical main body having both ends opened, and has a hot water supply opening opened at one side surface thereof to the plunger hole. A device for heating and keeping the upper half of the sleeve body on the free end side that is not supported by the platen of the die casting device on the side of the sleeve, and changing the free end with respect to the free end of the sleeve body.
Bending detection device provided to detect the position quantity, deformation control method of die casting plunger sleeve made configured to adjust the temperature difference between the upper half and lower half of the sleeve body. 2. The method according to claim 2, wherein the upper half of the sleeve body is
One or more holes are provided along the
According to claim 1 configured to so that providing a device for heating insulation
Deformation control method for die casting plunger sleeve. 3. A sleeve on the lower half of the sleeve body.
Configuration claims 1 or claim 2 deformation control method of die casting plunger sleeve according to provision of the fin.