Metal founding – Means to shape metallic material – Including means to hold or position preformed product part...
Reexamination Certificate
1998-12-02
2001-03-27
Pyon, Harold (Department: 1722)
Metal founding
Means to shape metallic material
Including means to hold or position preformed product part...
C164S333000, C164S334000
Reexamination Certificate
active
06206080
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method and apparatus for die casting rotor used in a motor, more particularly die casting apparatus for a rotor and method thereof which may eliminate a reworking process such as turning operations and broaching operations, and may simplify a manufacturing process by changing a mold's shape.
2. Prior Art
FIG. 1
is a sectional view partially showing a conventional die casting apparatus.
A conventional die casting apparatus, as shown in
FIG. 1
, has a stationary die plate
5
and an intermediate die plate
15
at the right side, and a movable die plate
21
and a base die plate
23
at the left side with reference to parting line PL. An extracting plate
10
for extracting the die cast rotor is mounted between the stationary die plate
5
and the intermediate die plate
15
.
An insert
4
forming a main passage
3
of molten aluminum is installed in the stationary die plate
5
.
A first mold
11
forming an annular first cavity
13
and a plurality of sprues
12
are installed in the intermediate die plate
15
. An annular sleeve
31
and a second mold
37
are mounted in the movable die plate
21
, and a preform
33
of the rotor is inserted on the second mold
37
.
The preform
33
consists of a plurality of circular stacks
34
, a central bore
32
, and a plurality of circularly arranged openings
35
.
A manufacturing process for a rotor using the above-mentioned die casting apparatus will be described below.
The molten aluminum of high temperature and pressure flows from the main passage
3
into an annular first cavity
13
through a plurality of sprues and then into an annular second cavity
39
passing through the openings.
If the molten aluminum is cooled, a die cast rotor is completed.
According to the above-mentioned die casting apparatus, because the molten aluminum is injected into the cavity of the first mold at high pressure, the molten aluminum leaks from the combination part between the first mold and an opposite surface of the movable die plate facing the intermediate die plate.
FIG. 2
is a perspective view of a die cast rotor by the conventional die casting apparatus. Referring to the die cast rotor shown in
FIG. 2
, the leaked molten aluminum is cooled on a upper periphery of the preform
33
, which results in forming projections
42
.
When the molten aluminum is filled and cooled in the annular first mold
11
and thus the first mold
11
is separated, a small quantity of the molten aluminum is cooled in a projected state along a plurality of sprue gates.
Therefore, a number of projections
45
are formed on an upper surface of the die cast rotor on which the sprue gates have been placed. Furthermore, because the molten aluminum is injected at high temperature and high pressure, an inner diameter of the preform is deformed, thereby concentricity of the die cast rotor may not be uniform. Accordingly, the rotor for a motor which is die cast by conventional die casting apparatus should be reworked by broaching operations and turning operations after die casting operation for precision manufacturing of the inner and outer diameters of the rotor.
THE SUMMARY OF THE INVENTION
To solve the above problems, it is a first object of the present invention to provide a die casting apparatus which can die cast a rotor having precise inner and outer diameters without independent reworking processes such as broaching operations and turning operations after die casting process.
It is a second object of the present invention to provide a die casting apparatus automatically cleaning plates by injecting high pressure water through a plurality of spraying holes of a sizing bar or a locator.
It is a third object of the present invention to provide a method and apparatus for die casting a rotor which simplifies a manufacturing process, and reduces processing time and manufacturing cost.
To obtain these objects, a die casting apparatus for a rotor comprises a stationary die plate mounting an insert in which a main passage of molten metal and a plurality of bores are formed, an extracting plate located on an opposite side of the insert which is able to move into the insert of the stationary die plate along a central axis and extracting metal scrap after die casting completion, an intermediate die plate mounting a plurality of first molds and receiving the extracting plate by moving toward the stationary die plate along the central axis, a movable die plate mounting a plurality of second molds and a plurality of sleeves for loading a preform respectively and moving forward together with the intermediate die plate toward the stationary die plate by pushing in abutment with said intermediate die plate, and a plurality of locators mounted on the stationary die plate by a nut and forming a plurality of spraying holes on each locator for cleaning the plates.
An annular inner wall and an annular outer wall of the first mold are projected against an opposite surface of the intermediate die plate facing the movable die plate for inserting said walls into the sleeve.
An annular first cavity is formed between said inner wall and said outer wall, and a plurality of sprues are penetrated from an upper surface of the first mold to the first cavity.
A plurality of gates are protruded from a bottom portion of the annular first cavity.
REFERENCES:
patent: 4064928 (1977-12-01), Wunder
patent: 4362205 (1982-12-01), Cole et al.
patent: 5332026 (1994-07-01), Thieman et al.
patent: 5538067 (1996-07-01), Nakamura et al.
patent: 2265251 (1977-03-01), None
patent: 1224100 (1986-04-01), None
Daewoo Electronics Co. Ltd.
Jacobson Price Holman & Stern PLLC
Lin I.-H.
Pyon Harold
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