Metal founding – Process – Shaping liquid metal against a forming surface
Patent
1993-10-20
1999-11-16
Lin, Kuang Y.
Metal founding
Process
Shaping liquid metal against a forming surface
164112, B22D 1908
Patent
active
059839759
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a die casting method for casting, in an object, a cylindrical liner in a cylindrical opening in the object, whereby a casting die insert component is placed inside the cylindrical liner, and a metal melt is pressurized against the outside of the liner. The invention is particularly but not exclusively directed to a method of die casting a cylinder block of aluminum in which cylinder liners of another material, such as cast iron or sintered metal, are cast in the cylinder openings.
BACKGROUND OF THE INVENTION
Today's aluminum engines of aluminum with cast-in cylinder liners are manufactured by die casting, which means that the aluminum melt is pressurized during the injection and hardening stages. In order to prevent the melt from penetrating into the cylinder liners, upper casting die insert components in the form of cylindrical bodies are used, which fill the liner, as well as lower casting die insert components, which abut the lower edges of the liners and the upper insert components, filling what is to become the cylinder block crank case.
The upper casting die insert is dimensioned so that a gap of about 0.2 mm is formed between the liner and the insert component when the liner is cold. This gap increases by about 0.5 mm to a total of about 0.7 mm upon heating to about 500.degree. C. upon contact with the melt. The pressure in the melt subjects the liners, however, to great pressure from the outside, and the liners are deformed so much that they come into contact with the insert component. The result is that the liners are subjected to great stresses during the casting process. These stresses are not desirable since they can give rise to out-of-roundness at a subsequent stage of the manufacturing process, and this in turn can require extra machining of the liners themselves.
OBJECT OF THE INVENTION
The purpose of the present invention is to develop the die casting method described above by way of introduction so that the risk of out-of-roundness due to stresses in the liners can be completely eliminated.
SUMMARY OF THE INVENTION
This is achieved according to the invention by virtue of the fact that a casting die insert component is used which leaves a gap between itself and the liner, and that the pressurized melt is allowed to penetrate into the gap to create equal pressure from the pressurized melt on both sides of the liner.
The invention minimizes in the casting stage external stresses on the liner, and this results in the liner being rounder after casting than is the case when previously known die casting methods are used. Shrink stresses which arise later are required to keep the liner in place and for heat transfer when the engine is running.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described in more detail with reference to an example shown in the accompanying drawings, wherein
FIG. 1 shows a cross section through a cylinder block with upper and lower casting die insert components, which are used in previously known die casting methods,
FIG. 2 shows schematically the pressure load on the liner in the known die casting methods,
FIG. 3 shows a cross section corresponding to FIG. 1 with upper and lower casting die insert components, which are used in the die casting method according to the invention, and
FIG. 4 is a schematic illustration corresponding to FIG. 2 of the die casting method according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, 1 and 2 designate opposite sides of a die cast aluminum blank for a cylinder block 3 after the pressurized melt has hardened and after the die components (not shown) in contact with the sides 1 and 2 have been removed, but before the upper and lower insert components 4 and 5 of the die have been removed. The upper insert component 4 of the die is a cylindrical body for each cylinder in the cylinder block, while the lower insert component 5 is a body 7 conforming to the shape of the crank case 6. The diameter of the cylinder 4 is so adapted to
REFERENCES:
patent: 4738298 (1988-04-01), Taruno et al.
AB Volvo
Lin Kuang Y.
LandOfFree
Method of die casting does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of die casting, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of die casting will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1311767