JPH0523816A - Plunger sleeve for die casting machine - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks in a ceramic at the time of pouring a molten metal by forming divisionally a ceramic-made inner cylinder for plunger sleeve set in a sideway falling posture into plural numbers at upper and lower parts. CONSTITUTION:By forming the ceramic inner cylinder 3 for plunger sleeve divisionally into upper and lower parts, the sleeve is constituted of the divided members 6, 7. At the time of pouring a molten metal, since the molten metal is retained only in the upper part, large temp. difference is generated between the upper part and the lower part in the inner cylinder 3, but since the ceramic is divided, thermal stress can be reduced. Therefore, the generation of cracks in the ceramic inner cylinder 3 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a posture in which a molten metal is received and a plunger tip for injecting the received molten metal into a mold by injecting the molten metal is slidably fitted inside. The present invention relates to a plunger sleeve of a die casting machine, more specifically, to a ceramic sleeve in which a steel inner sleeve is fitted inside a steel sleeve.

[0002]

2. Description of the Related Art In the plunger sleeve of the above die casting machine, the inner cylinder has conventionally been formed of a cylindrical body.

[0003]

However, the supply amount of the molten metal injected into the die of the die-casting machine body by the plunger tip is usually smaller than the inner volume of the plunger sleeve, and therefore, the inner volume of the plunger sleeve is small. When the molten metal is injected into the container, the molten metal stays only in the lower part of the plunger sleeve in the sideways posture. However, at the time of this injection, the molten metal is at a high temperature and the lower part of the plunger sleeve that is in contact with it is heated directly, so that a large temperature difference occurs between the upper part and the lower part of the plunger sleeve, resulting in a large difference in thermal shock force. Therefore, there is a risk that cracks may occur in the inner cylinder. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plunger sleeve of a die casting machine in which a ceramic inner cylinder is unlikely to crack when molten metal is injected.

[0004]

[Means for Solving the Problems] In a plunger sleeve of a die casting machine in which a ceramic inner cylinder is fitted inside a steel sleeve and which is installed in a sideways posture, the above object is achieved. A characteristic configuration of the present invention is that the inner cylinder is divided into a plurality of upper and lower members, and in particular, the lower member of the divided inner cylinder is divided into a plurality of members in the axial direction. It is effective to add the formed points to the characteristic structure for the reason described below.

[0005]

[Function] As the molten metal is injected into the plunger sleeve, the temperature of the lower part of the ceramic inner cylinder in which the molten metal stays rises and gradually propagates to the upper part. A temperature gradient is generated in which the temperature decreases in the vertical direction toward the top. Therefore, by dividing the inner cylinder into a plurality of upper and lower members, the inner cylinder can be subdivided in the vertical direction to subdivide the temperature difference, and adjacent members among the upper and lower divided members Since they can be slightly offset from each other, the difference in thermal expansion due to the temperature difference can be subdivided into the plurality of members, and the stress acting on each of the divided members can be reduced. Further, in the case where the lower member of the divided inner cylinder is divided into a plurality of parts in the axial direction, the lower member of the divided inner cylinder, That is, it is possible to reduce the stress acting by making the amount of thermal expansion of each of the divided ones that is most subjected to the thermal shock at the time of pouring the molten metal smaller.

[0006]

As described above, it is possible to provide a plunger sleeve for a die-cast machine in which a ceramic inner cylinder is less likely to be cracked when molten metal is injected into the plunger sleeve and durability is improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A plunger sleeve of a die casting machine for an aluminum alloy according to an embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the plunger sleeve 1 includes a steel sleeve 2 and a ceramic inner cylinder 3 fitted inside the steel sleeve 2.
It is composed by.

The steel sleeve 2 is fitted onto the outer peripheral surface of the inner cylinder 3 by shrink fitting, and is closely contacted with the outer peripheral surface of the inner cylinder 3 so as not to rattle, and at both ends. A screw thread 4 is formed on each of them, and S is attached to this screw thread 4.
A fixing ring 5 formed of KD-61 is screwed into the steel sleeve 2 so that the inner cylinder 3 inside the steel sleeve 2 does not come out.

As shown in FIG. 2, the inner cylinder 3 is divided into upper and lower parts and is composed of two dividing members 6 and 7. The joining between the end faces of the upper and lower two split members 6 and 7 is such that the end faces mesh with each other, and the upper split member 6 and the lower split member 7 are joined to each other at their joined end faces. It is possible to be slightly displaced in the axial direction.

Therefore, the thermal shock force of the injected molten metal can be subdivided into the upper member 6 and the lower member 7, and the thermal stress due to the thermal shock can be reduced.

In order to prevent the heat generated by the molten metal from directly acting on the upper and lower split members 6 and 7, the joining position of the upper and lower members 6 and 7 is the retention position of the molten metal injected into the plunger sleeve 1. The temperature may be set higher than that, so that the thermal shock can be reduced so as not to increase the temperature difference in the upper division member 6.

In the above embodiment, the inner cylinder 3 is divided into two parts in the vertical direction, but it may be divided into three or more parts. By increasing the number of divisions in such a manner,
The thermal stress can be dispersed to increase the portion that can be subdivided.

In the above-described embodiment, the fixing ring 5 is provided so that the inner cylinder 3 located inside the steel sleeve 2 does not come out.
Are provided on both ends of the steel sleeve 2, respectively, but a fixing ring may be provided only on one end side and the steel sleeve 2 on the other end side is formed in a tapered portion so as to be a recess. That is, when the fixing ring on one end side is screwed toward the taper portion of the other end frame, the fixing ring on the inner side of the steel sleeve contacts the taper portion of the inner cylinder. The inner cylinder can be firmly locked in the steel sleeve so that the end side is firmly pressed against the tapered portion so as not to rattle.

Although this embodiment is for an aluminum alloy, other magnesium (M
g), zinc (Zn), tin (Sn), copper (Cu), molybdenum (Mo) and the like, or the alloy sleeve of the present invention can be applied as a plunger sleeve of a die casting machine for casting a high temperature molten metal. The port formed on the plunger sleeve 1 (upper right side of the plunger sleeve in FIG. 1) is an injection port 9 for injecting the molten metal.

[Other Embodiments] In the lower member of the divided ceramic inner cylinder, the above embodiment adopts an integral member, but the present invention is not limited to this, and the inner cylinder axial insertion direction is not limited to this. 3 may be separately formed in a plurality of directions, and an example is shown in FIG. 3, that is, in the state where the lower member 7 is a small piece 8 having the curvature of the inner cylinder 3 and the end faces thereof are abutted against each other. The inner cylinder 3 is divided into a plurality of parts at equal pitches in the axial direction. Then, the thermal stress due to the injected molten metal can be subdivided by the small pieces 8, and the damage due to the thermal shock can be further reduced.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

[Fig. 1] Vertical side view of the plunger sleeve

FIG. 2 is a perspective view of a ceramic inner cylinder.

FIG. 3 is a perspective view of a ceramic inner cylinder of another embodiment.

[Explanation of symbols]

2 Steel sleeve 3 Ceramic inner cylinder 6 Upper member 7 Lower member

Claims (2)

[Claims] 1. A plunger sleeve for a die-casting machine, wherein a ceramic inner cylinder (3) is fitted inside a steel sleeve (2) and is installed in a sideways posture. A plunger sleeve for a die-casting machine in which (3) is divided into a plurality of upper and lower members. 2. A plunger sleeve for a die casting machine according to claim 1, wherein the lower member (7) of the divided inner cylinder (3) is divided into a plurality of pieces in the axial direction thereof. .