JPH0741557Y2 - Die casting sleeve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a die casting sleeve constituting a molten metal injection device in a horizontal or vertical die casting machine for non-ferrous metals such as aluminum alloys,
In particular, the present invention relates to a die-cast sleeve having a composite structure in which an inner cylinder made of a ceramic material is fitted in an outer cylinder made of a metal material.

[Conventional technology]

Generally, in an injection device of a cold chamber type die casting machine, molten metal is supplied into the sleeve,
Molten metal is injected into a mold cavity communicating with the sleeve by a plunger tip that slides in the sleeve. Therefore, the inner surface of the sleeve is often melted by molten metal or worn by sliding the plunger tip. If the inner surface of the sleeve is damaged due to these melting and wear, the molten metal enters between the sleeve and the plunger tip, the sliding resistance of the sleeve increases, and stable injection cannot be performed, resulting in deterioration of product quality. This also leads to deterioration of workability and further damage to the inner surface of the sleeve. Further, if a large amount of lubricant is used to reduce the sliding resistance between the sleeve and the plunger tip or prevent seizure, it is not preferable because impurities are mixed into the molten metal and the product quality is deteriorated.

For this reason, a nitride steel sleeve having a hardness of about HRC65 (HV832) has been conventionally used. The use of such a nitrided steel sleeve reduces wear and melt damage on the inner surface of the sleeve, but this has not yet been solved in terms of the durability of the sleeve and the quality of products cast using this sleeve. Is left.

Therefore, a die-casting sleeve has been developed in which a ceramic inner cylinder having heat resistance and wear resistance is fitted to the inner peripheral surface of a steel sleeve into which a plunger tip is fitted.
Some are disclosed in 7555, 61-103658, etc. These configurations are those in which a metal outer cylinder is shrink-fitted and reinforced on the outside of the ceramic inner cylinder, and further, by cooling this metal outer cylinder, the shrinkage effect due to temperature rise is prevented from decreasing. Is.

[Problems to be solved by the device]

As described above, by using the sleeve in which the ceramic inner cylinder is fitted in the metal outer cylinder, troubles such as melting loss, wear, and seizure are drastically reduced, but the following new problems occur. That is, there is a problem in that a difference in thermal expansion between the metal outer cylinder and the ceramic inner cylinder causes a difference in elongation in the axial direction, a tensile stress acts on the ceramic inner cylinder, and a crack occurs in the circumferential direction. . Further, when the outer cylinder is cooled in order to prevent the shrinking fitting effect from being reduced due to the temperature rise of the outer cylinder, the temperature of the molten metal supplied into the sleeve is lowered, which causes a problem that the molten metal fails.

Therefore, the inventors have formed an outer cylinder with a high-strength and low-expansion metal material without cooling the outer cylinder, and press an inner cylinder made of a ceramic material with a fixing ring provided at the end of the outer cylinder. ， We devised a die-casting sleeve with a holding structure,
I have already applied. With this device, most of the problems of the above-mentioned conventional techniques can be solved.

However, because of the non-cooling method, when the outer cylinder member reaches a high temperature of 400 to 450 ° C during use, even if the outer cylinder constituent material is a low expansion metal material, the shrink fitting effect is slightly However, there is room for some improvements.
Further, in the case of a die casting sleeve used in a die casting machine with a large injection pressure, a large internal pressure is applied to the end of the die side in particular, so that the conventional structure has insufficient strength. There is a point.

The present invention solves the above-mentioned problems existing in the prior art, prevents cracks from occurring in the ceramic inner cylinder, prevents molten metal rotation defects due to temperature drop of the molten metal, and has a shrink fitting effect between the inner and outer cylinders. It is an object of the present invention to provide a die-casting sleeve that can be used for a die-casting machine with high injection pressure.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, in the present invention, a hollow cylindrical shape is formed from a high-strength, low-expansion metal material of any one of Fe-Ni alloy, Fe-Ni-Co alloy, and Ti alloy. In the outer cylinder,
A reinforcing ring for increasing the pressure resistance on the die side of the outer cylinder and the inner cylinder formed of a ceramic material in the shape of a hollow cylinder, and a stepped portion formed on the inner surface of the reinforcing ring is formed on the outer cylinder and the inner cylinder. We adopted the technical means of abutting against the end face of the fitting and fitting it, and providing a refrigerant circulation path in the reinforcing ring.

[Action]

With the above structure, a pressing force in the axial direction can be applied to the inner cylinder made of a ceramic material, so that compressive stress is applied to the inner cylinder. On the other hand, since the metal material forming the outer cylinder has a low expansion property, even if the molten metal is supplied to the inner cylinder and the temperature rises, the compression force in the radial direction against the inner cylinder is extremely small, and the shrink fitting The effect can be maintained. Further, since a hollow ring having a refrigerant circulation path is fitted around the outer periphery of the die side end portion of the outer cylinder, it is possible to sufficiently withstand the internal pressure caused by the injection pressure.

〔Example〕

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention, which is an example of a sleeve for a horizontal die casting machine. 1 in the figure
Is an outer cylinder, for example, FCA-Ni35 (JIS
G5510) forms a hollow cylinder with an outer diameter of 135 mm, an inner diameter of 95 mm, and a length of 370 mm. Next, 2 is an inner cylinder, which is made of a ceramic material into a hollow cylindrical shape having an outer diameter of 95 mm, an inner diameter of 75 mm, and a length of 370 mm, and is fitted into the outer cylinder 1 by shrink fitting. The shrinkage fitting ratio in this case is 0.3 / 1000 to 3/1000. Numerals 3 and 4 are a fixing ring and a reinforcing ring, respectively, which are formed of hot work tool steel and are fixed to both ends of the outer cylinder 1 and end faces of which are the inner cylinder 2
The inner cylinder 2 is firmly clamped in the axial direction by being brought into contact with both end surfaces of the inner cylinder 2. First, the fixing ring 3 on the plunger side is formed, for example, in the shape of a hollow disk, and is fixed to the end surface of the outer cylinder 1 with a bolt (not shown). On the other hand, the reinforcement ring 4 that should be provided on the mold side
Has a tapered inner surface at the open end, and is provided with a stepped portion 4a on the inner surface so that it can contact the end surfaces of the outer cylinder 1 and the inner cylinder 2, and has a step with an outer diameter of 150 mm, an inner diameter of 115 mm, and a length of 180 mm. It is formed into a hollow cylindrical shape with an outer cylinder and is fitted and fixed to the outer circumference of the end portion of the outer cylinder 1 by shrink fitting. In this case, the shrink fitting rate is preferably 0.3 / 1000 to 5/1000. A refrigerant circulation path 4b is provided in the reinforcing ring 4. Reference numeral 5 denotes an inlet, which opens near the ends of the outer cylinder 1 and the inner cylinder 2 on the plunger side.

The die-casting sleeve with the above structure has a mold clamping force of 800 tons.
It was confirmed that it could withstand more than 100,000 shots as a result of being attached to the injection equipment of the horizontal die casting machine and used for aluminum alloy die casting. Even after the above-mentioned use, the inner tube 2 is melted and worn by the molten metal on the inner surface, wear,
There were no problems such as seizure, and no cracks were found in the inner cylinder 2 in the axial and circumferential directions. In this case, the cooling water can be circulated in the refrigerant circulation path 4b provided in the reinforcing ring 4 to hold the reinforcing ring 4 at 50 to 70 ° C, and the shrink fitting between the reinforcing ring 4 and the outer cylinder 1 can be loosened. Was not recognized at all.

In this embodiment, the sleeve for the horizontal die casting machine is described, but it is naturally applicable as a sleeve for a vertical die casting machine that uses the axis in a vertical state. In addition, FC is used as a low-expansion metal material that forms the outer cylinder.
Although an example using A-Ni35 was described, other materials such as FCDA-Ni35, Ti-6Al-4V alloy and other T
i-based alloys, other Fe-Ni-based materials such as Invar, or
An alloy such as Fe-Ni-Co system can be used. Further, as the ceramic material forming the inner cylinder, at least one having excellent erosion resistance to the injected molten metal may be used, and nitride, carbide, boride, oxide or the like may be appropriately used. Furthermore, the means for attaching and joining the fixing ring on the plunger side to the outer cylinder is
Not only screws and bolts, but other mechanical and metallurgical means can be used as long as they can press the inner cylinder in the axial direction. Furthermore, the die casting sleeve of the present invention is not limited to aluminum alloys, and can naturally be applied to other die casting alloys. A fluid other than water may be used as the cooling medium for cooling the reinforcing ring on the die side.

[Effect of device]

Since the invention of the present application has the configuration and operation as described above, the axial tensile stress acting on the inner cylinder made of a ceramic material can be made to be absent or extremely small, and the shaft generated in the inner cylinder can be reduced. It is possible to completely prevent not only directional cracks but also circumferential cracks. In addition, the shrink fitting between the inner and outer cylinders can be eliminated altogether, and since the pressure resistance on the die side is increased, it can also be applied to die casting machines with high injection pressure. As a result, various characteristics such as wear resistance, corrosion resistance, and heat insulation property inherent in ceramic materials can be fully exerted, and it can significantly contribute to the improvement of the durability of die casting sleeves, the yield of die casting products, and the energy cost. There is.

[Brief description of drawings]

 FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of the present invention. 1: Outer cylinder, 2: Inner cylinder, 4: Reinforcement ring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Itsuo Korenaga 1-9-1 Kitahama, Wakamatsu-ku, Kitakyushu City, Fukuoka Prefecture Hitachi Metals Co., Ltd. Wakamatsu Factory (56) Reference JP-A-52-44726 (JP, A) ) Actually open 2-133254 (JP, U) Actually open 60-176860 (JP, U) Actually open 63-174955 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A ceramic material is provided inside a hollow cylinder formed of a high-strength, low-expansion metallic material of any one of Fe-Ni alloy, Fe-Ni-Co alloy and Ti alloy. To fit a hollow cylinder-shaped inner cylinder into a hollow cylinder on the outer periphery of the outer cylinder on the mold side, and to increase the pressure resistance of the outer cylinder and the inner cylinder on the mold side. A sleeve for die casting, characterized in that a reinforcing ring is fitted by fitting a stepped portion formed on the inner surface to the end surfaces of the outer cylinder and the inner cylinder, and a refrigerant circulation path is provided in the reinforcing ring. .