Metal founding – Means to shape metallic material – Pressure shaping means
Patent
1989-06-06
1991-04-30
Seidel, Richard K.
Metal founding
Means to shape metallic material
Pressure shaping means
164303, B22D 1710, B22D 1720
Patent
active
050109464
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a molten metal-injecting cylinder in a die casting machine for nonferrous metals such as aluminum alloys, and more particularly to a die casting cylinder of a composite structure comprising an outer cylindrical member made of a metal material and an inner cylindrical member made of a ceramic material and fixed in the outer cylindrical member.
BACKGROUND OF THE INVENTION
In general, a cold chamber-type die casting machine comprises as an injection means a horizontal cylinder having an inlet opening in an upper side wall thereof near its end, and a charge of molten metal is introduced into the cylinder through the inlet opening and injected into a die cavity communicating with the cylinder by means of a piston slidably moving in the cylinder. Since the molten metal directly drops onto and collides with the inner surface of the cylinder particularly just below the inlet opening, it is likely that the inner surface of the cylinder is subjected to erosion in such a portion, and that it is worn by sliding contact with the piston. When the inner surface of the cylinder is damaged by these erosion and wear cycles, the molten metal can leak into a gap between the cylinder and the piston, resulting in an increase in the sliding resistance of the piston. This in turn reduces the injection rate, which leads not only to the deterioration of qualities of injection products but also to the reduction of productivity and to a further increase in damage of the inner surface of the cylinder. If a large amount of a lubricating agent is used to reduce the sliding resistance between the cylinder and the piston and to prevent seizure, it could be entrained into the molten metal as an impurity, resulting in the deterioration of product quality.
In view of these problems, cylinders made of nitrided steel having a hardness of H.sub.R C 65 (H.sub.V 832) or so have conventionally been used. The use of such nitrided steel decreases the wear and erosion of the inner surface of the cylinder, but nitrided steel is still unsatisfactory in terms of the durability of the cylinder and the quality of products cast by using such a cylinder.
Accordingly, various proposals have been made to provide a die casting cylinder in which a heat-resistant, wear-resistant ceramic cylinder is fixed in a steel cylinder, into which a piston is inserted.
U.S. Pat. No. 3,664,411 discloses a die casting cylinder comprising a metal casing and a ceramic liner having good resistance to corrosion by molten metals and thermal fatigue resistance, the ceramic liner affording an external surface of slightly tapered form and the casing affording an internal surface having a taper complementary to that of the liner, whereby the liner and the casing are assembled together as a press fit so that the liner is supported by the casing at all positions along its length.
Japanese Patent Laid-Open No. 53-70034 discloses a die casting apparatus comprising a melt injection cylinder in which a plurality of separate ceramic sleeve pieces are assembled.
Japanese Patent Laid-Open No. 61-67555 discloses an injection sleeve for die casting, having a dual structure consisting of an inner cylinder and an outer cylinder, between which a water-cooling jacket is provided.
Further, Japanese Patent Laid-Open No. 61-103658 discloses an injection cylinder for a die casting machine comprising a cylinder body into which a piston is inserted, and an inner cylinder made of a nonferrous metal material having extremely high heat resistance and wear resistance such as a ceramic or a cermet, which is fit under proper pressure in the cylinder body at least near an inlet opening for a molten metal, the cylinder body being provided with at least one path for introducing a heating medium.
The above-mentioned structures in which ceramic inner cylinders are fit in the cylinder bodies are extremely effective for improving the wear resistance and corrosion resistance of the cylinders, but there is still a room for improvement in that the temperature of
REFERENCES:
patent: 3664411 (1972-05-01), Garver
patent: 3685572 (1972-08-01), Carver et al.
Furushima Kiyoshi
Korenaga Itsuo
Nogami Shingo
Okitsu Toshio
Yashiro Toshinori
Batten, Jr. J. Reed
Hitachi Metals Ltd.
Seidel Richard K.
LandOfFree
Die casting cylinder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Die casting cylinder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Die casting cylinder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-634529