JPH0647515A - Injection device in die casting machine - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To improve the heat retention of the molten metal and to reduce the expansion of the injection sleeve to keep the gap between the plunger tip and a certain value or less. [Structure] An injection sleeve of an injection device of a die casting machine is provided with an inner cylinder 5 and an outer cylinder 4 made of metal and an intermediate cylinder 1 having a low thermal conductivity.
Place each 4 tightly. Further, a cooling device 11 is provided on the outer peripheral portion of the outer cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting machine equipped with an injection sleeve capable of preventing the backflush by improving the heat retention of the molten metal, reducing the expansion of the injection sleeve, and keeping the gap between the plunger tip and the plunger chip below a certain value. Of the injection device.

[0002]

2. Description of the Related Art As a conventional technology of an injection sleeve used in an injection device of a die casting machine, for example, the Japanese Utility Model No. 2
-22130 and Japanese Patent Application No. 2-49343. In the technique disclosed in Japanese Utility Model Publication No. 2-22130, a cylinder into which a plunger tip is slidably inserted is made of ceramics, and a hollow heat insulating holder holds only both ends of the cylinder, and the cylinder is axially moved. By pre-compressing, the molten metal heat retention of the injection sleeve is improved and at the same time the ceramic inner cylinder is prevented from cracking due to axial stress and durability is improved. The technique described in Japanese Patent Application No. 2-49343 discloses a ceramic inner cylinder into which a plunger tip is slidably inserted, an intermediate cylinder shrink-fitted or chilled with the inner cylinder, and an intermediate cylinder. The present invention relates to an injection sleeve composed of an outer cylinder which holds only at a few places and forms a hollow portion with the outer peripheral surface of the intermediate cylinder, and a spacer which presses one end surface of the intermediate cylinder and the inner cylinder. This is to hold and prevent loose fitting of the inner cylinder and the intermediate cylinder.

[0003]

However, in the technique disclosed in Japanese Utility Model Publication No. 2-22130, most of the inner cylinder is made of ceramics because the inner cylinder is held by the outer cylinder only at both ends thereof. At, radial precompression is not working. For this reason, if the amount of hot water supplied was excessive or the solidified alloy adhered to the inner surface of the inner cylinder, internal pressure was generated in the inner cylinder, and the ceramic inner cylinder was sometimes cracked. In addition, Japanese Patent Application No. 2-493
In the technology described in No. 43, in order to prevent the inner cylinder from cracking, the inner cylinder is tightly fitted by the intermediate cylinder to control the temperature of the intermediate cylinder, but the central portion in the axial direction has a radial direction. Is not maintained (actual fair 2-22130
Or, even if there is, the temperature rises due to the heat transfer from the molten metal (Japanese Patent Application No. 2-49343), so that the inner cylinder and the intermediate cylinder whose temperature has risen expands. Therefore, the gap between the plunger tip and the plunger tip becomes large, and the molten metal enters the gap between the plunger tip and the inner cylinder. At the holding parts at both ends of the inner cylinder and / or the middle cylinder, the restraint by the outer cylinder and the temperature rise are low, so there is no expansion as much as in the central part, and the wedge effect due to the solidified material between the plunger tip and the inner cylinder as the plunger tip advances Because of this, internal pressure was generated in the inner cylinder, which could crack the inner cylinder.
In the technique described in Japanese Patent Application No. 2-49343, although the difference in the gap between the plunger tip and the inner cylinder can be eliminated by strengthening the cooling of the intermediate cylinder and keeping the expansion degree of each part of the inner cylinder equal, the sleeve is still present. There was a defect that the heat retention effect of was lost.

[0004]

In order to solve such a problem, in the present invention, an injection device of a die casting machine in which a molten metal is put in an injection sleeve and the molten metal is filled in a mold cavity by an injection plunger. In the above, as the injection sleeve, an injection sleeve having a structure in which a metallic inner cylinder, an outer cylinder, and an intermediate cylinder having a low thermal conductivity are tightly fitted and arranged, and a cooling device is provided on the outer peripheral portion of the outer cylinder, Using.

[0005]

According to the above construction, the outer cylinder is uniformly cooled by the cooling device provided on the outer circumference of the outer cylinder, the expansion of the inner diameter of the inner cylinder is suppressed, and the gap between the plunger tip and the inner cylinder is controlled to an optimum value. You can At the same time, the inner cylinder can be kept at a high temperature due to the low thermal conductivity of the intermediate cylinder and the heat insulation effect due to the contact thermal resistance between the intermediate cylinder, the inner cylinder and the outer cylinder.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to one embodiment shown in the drawings. FIG. 1 is an example in which the present invention is applied to a vertical squeeze casting machine, which is one type of vertical die casting machine. In the figure, 1 is a fixed platen, 2 is a fixed mold, 3 is a mold sleeve, 4 is an outer cylinder, 5 is an inner cylinder, 6 is a plunger chip, 7 is a docking frame, 8 is an injection cylinder, and 9 is a tilting cylinder. , 11 is a sleeve cooling jacket, 12 is a ram, 13 is a ram cylinder, 14 is an intermediate cylinder, 18 is an upper end ring, and 20 is a lower end ring.

The injection device is tilted by the tilting silling 9, and hot water is supplied at a position where the fixed platen 1 is passed. After the hot water is supplied, the injection device is returned to the injection position by the tilting cylinder 9, after which the die sleeve 3 and the injection device are docked by the ram 12, and then the molten metal is injected into the cavity by the plunger tip 6.

In the injection sleeve 30 shown in FIGS. 2 and 3, an inner cylinder 5 made of metal (for example, hot work tool steel), an intermediate cylinder 14 having low thermal conductivity (for example, zirconia ceramics or titanium sintered alloy), and an outer cylinder. The cylinder 4 (for example, carbon steel for general structure) is shrink-fitted or cold-fitted, and
The outer peripheral portion of the inner cylinder 5 and the outer peripheral portion of the intermediate cylinder 14 are respectively provided with concave portions 25 which are concavely formed at regular intervals to form an air reservoir. In this way, the air reservoir is formed to reduce the contact area of the interference fit portion of each cylinder, thereby reducing the heat transfer area and enhancing the heat retaining effect of the molten metal A. The recess 25 may be provided in the inner peripheral portion of the intermediate cylinder 14 and the inner peripheral portion of the outer cylinder 4.

An upper end ring 18 is provided at the tip of the injection sleeve 30, and a lower end ring 20 is provided at the lower end.
Is arranged to fix the metal inner cylinder 5 and the intermediate cylinder 14 having a low thermal conductivity in the axial direction. A sleeve cooling jacket 11 is provided on the outer peripheral portion of the outer cylinder 4 to forcibly cool it and prevent the injection sleeve 30 from expanding outward in a drum shape due to the high temperature molten metal A.

By fixing the inner cylinder 5 and the intermediate cylinder 14 to the outer cylinder 4, the inner cylinder 5 and the intermediate cylinder 14 are poured by pouring.
When the temperature rises, the temperature difference from the outer cylinder 4 occurs, and the axial compression and the radial compression act on the inner cylinder 5 and the intermediate cylinder 14. Because of this compression,
Even if axial and radial stress acts on the intermediate cylinder 14, it becomes difficult to crack. Further, since the inner cylinder 5 and the intermediate cylinder 14 are axially shrink-fitted or cold-fitted with the outer cylinder 4, a larger pre-compression is generated in the intermediate cylinder 14 and the intermediate cylinder 14 is more difficult to break. Outer cylinder 4
By forced cooling, the axial and radial compression that occurs when pouring is further increased,
The intermediate cylinder 14 becomes more difficult to break. Even if it breaks, there is no problem because it is sandwiched between the inner cylinder 5 and the outer cylinder 4. By making the intermediate cylinder 14 slightly longer than the inner cylinder 5, precompression generated in the intermediate cylinder 14 at the time of shrink fitting or cold fitting of the inner cylinder 5, and the intermediate cylinder 14 and the outer cylinder 4 can be increased. The injection sleeve 30 including the outer cylinder 4, the inner cylinder 5 and the intermediate cylinder 14 is attached to the docking frame 7 by the coupling 17.

In the present invention, when the molten aluminum A of about 700 ° C. is put in the injection sleeve 30, the outer cylinder 4
The outer cylinder 4 is desired by arranging the cooling medium conduit 21 in the sleeve cooling jacket 11 on the outer peripheral portion of the casing and adjusting the amount of the introduced cooling medium by introducing, for example, normal temperature air or cooling water as the cooling medium. The temperature is controlled so that the temperature reaches the desired temperature. In this way, by controlling the outer cylinder 4 to be below a certain temperature, it is possible to prevent the drum-shaped expansion shape (a state in which it expands outward) of the injection sleeve 30 caused by the temperature rise of the outer cylinder 4.

Further, the sleeve cooling jacket 11 is arranged on the outer peripheral portion of the outer cylinder 4 and the outer cylinder 4 is measured by a temperature sensitive element to control the temperature below a certain temperature, and the intermediate cylinder 14 is made of a material having a low thermal conductivity. Is used to form a heat transfer resistance band to prevent heat transfer from the inner cylinder 5 to the outer cylinder 4. Further, regarding the heat flow from the inner cylinder 5 to the intermediate cylinder 14 described above,
A concave portion 25 is arranged on the outer peripheral portion of the intermediate cylinder 14 and a concave portion 26 is arranged on the outer peripheral portion of the intermediate cylinder 14 for heat flow from the intermediate cylinder 14 to the outer cylinder 4 to reduce the heat transfer area.
The air staying at 6 has a heat insulating effect.

Moreover, a water pipe 16 for cooling the plunger tip 6 is provided at the center of the plunger tip rod 6a.
Is provided, and the cooling water that has flowed from the lower side to the upper side in the water pipe 16 flows down through a gap provided between the tip joints 23 on the outer periphery of the water pipe 16. Therefore, when the cooling water is passed, the plunger tip 6
Of the molten metal A can be smoothly injected into the cavity in combination with the expansion prevention of the inner cylinder 5 of the injection sleeve 30 described above.

In the present invention, as described above, the inner cylinder 5 can be maintained at a high temperature by the heat insulating effect of the triple, and the heat retaining effect of the molten aluminum in the injection sleeve 30 can be greatly enhanced.

Although the coil cooling medium conduit 21 is arranged in the sleeve cooling jacket 11 in this embodiment, the invention is not limited to this, and a spiral groove may be provided, or any cooling pipe may be provided. You may make it the space part shape which does not arrange.

[0016]

As is apparent from the above description, in the present invention, the die casting machine injection device is provided with the metal inner cylinder, the outer cylinder, and the low thermal conductivity intermediate cylinder as the injection sleeve. The injection sleeve having the structure in which the outer cylinder is fitted and arranged with the cooling device provided on the outer peripheral portion suppresses the expansion of the inner cylinder inner diameter and sets the gap between the plunger tip and the inner cylinder to the optimum value. At the same time, the inner cylinder can be maintained at a high temperature due to the low thermal conductivity of the intermediate cylinder and the heat insulation effect due to the contact thermal resistance between the intermediate cylinder and the inner cylinder and the outer cylinder. Furthermore, since the inner cylinder is made of metal, it does not crack like ceramics. Also, if ceramics are used for the intermediate cylinder, they can be used without any problems even if the ceramics breaks.

[Brief description of drawings]

FIG. 1 is an example in which an injection sleeve according to the present invention is applied to an injection device of a die casting machine.

FIG. 2 is an enlarged vertical sectional view of a main part of an injection sleeve according to the present invention.

FIG. 3 is a partially enlarged sectional view of FIG.

[Explanation of symbols]

 1 Fixed Plate 2 Fixed Mold 3 Mold Sleeve 4 Outer Cylinder 5 Inner Cylinder 6 Plunger Chip 7 Docking Frame 8 Injection Cylinder 9 Tilt Cylinder 11 Sleeve Cooling Jacket 14 Middle Cylinder 18 Upper End Ring 20 Lower End Ring 21 Coolant Conduit 25 , 26 concave 30 injection sleeve

Claims (1)

[Claims] 1. An injection device of a die casting machine, in which a metal inner cylinder, an outer cylinder, and an intermediate cylinder having a low thermal conductivity are tightly fitted and arranged, and a cooling device is provided on an outer peripheral portion of the outer cylinder. An injection device for a die casting machine, which is equipped with an injection sleeve having a structure.