JPH08238555A - Mold for plural pieces of casting - Google Patents

Abstract

PURPOSE: To provide a mold for plural pieces of casting, in which plural pieces of casting having good dimensional precision can be obtd. CONSTITUTION: The mold 7 for plural pieces of casting is provided with a cylindrical runner 8 and cavities 9 for forming plural pieces of casting communicated with the runner 8 and arranged radially around the axial line (a) of the runner. Plural joint surfaces (b) are arranged radially around the axial line (a) of the runner to bisect each cavity 9. Since each mold constituent body 111 has half part 9a of the cavity on each of both side surfaces (c) to be the joint surface (b), the thermal condition during casting is almost uniform on both side surfaces (c) of the mold constituent body 11. By this constitution, the occurrence of the positional shifting between half parts 9a of the cavity of respective mold constituent bodies 11 adjacent to each other is prevented, and the casting having good dimensional precision can be obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a multi-cavity casting mold, in particular, a cylindrical runner, and a plurality of casting cavities which communicate with the runner and are arranged radially about the runner axis. For improved molds.

[0002]

2. Description of the Related Art Heretofore, as this type of mold, a stack mold has been known in which each cavity is divided into two parts by a mold matching surface intersecting with a runner axis (for example, Japanese Patent Laid-Open No. 281034/1990). reference).

[0003]

However, in the conventional stacking mold, each constituent mold comprising a pair of mold halves is made thin, and one surface of each mold half is molten metal. Since the other half of the mold is in contact with the molten metal and the other surface does not come into contact with the molten metal, the two mold halves are reciprocal in opposite directions during casting, which easily causes displacement between the two mold halves. As a result, the dimensional accuracy of the casting is reduced, and it also fluctuates.

In view of the above, the present invention provides the above-mentioned multi-cavity casting mold capable of preventing a positional deviation between the two cavity halves and obtaining a plurality of castings having good and constant dimensional accuracy. The purpose is to do.

[0005]

DISCLOSURE OF THE INVENTION The present invention is directed to a multi-cavity product having a cylindrical runner and a plurality of casting cavities which are connected to the runner and are arranged radially around the runner axis. The mold has a plurality of mold-matching surfaces that are radially arranged around the runner axis and divide each cavity into two halves.

[0006]

When the mold is provided with a plurality of mold matching surfaces as described above, the mold is divided into a plurality of mold constituents. Since each mold structure has cavity halves on both side surfaces that form the mating surface, the thermal conditions during casting are substantially the same on both side surfaces of each mold structure.
As a result, it is possible to prevent positional displacement between the two cavity halves of the two adjacent mold constituents, and to obtain a plurality of castings that are good and have a constant dimensional accuracy.

[0007]

EXAMPLE In FIG. 1, a pin-shaped casting 1 is made of a TiAl-based intermetallic compound and is cast under the application of vertical centrifugal casting.

2 to 5 show a vertical centrifugal casting apparatus 2 for taking many pin-shaped castings 1. In the device 2, as shown in FIG. 3, the rotary shaft 3 is made of stainless steel and is arranged so that its axis extends in the vertical direction.
The lower end side of the rotating shaft 3 is connected to a rotating mechanism (not shown).
A rotary disk 5 is fixed to a mounting flange portion 4 at the upper end of the rotary shaft 3 by a plurality of bolts 6, and the rotary disk 5 is made of a copper alloy.

A cylindrical mold 7 is installed on the turntable 5 as a multi-cavity casting mold. The mold 7 is made of pure copper having a purity of 99.9%, and is provided with a cylindrical runner 8 extending in the up-down direction and a plurality of pin-shaped casting molding cylindrical cavities 9 having one end directly connected to the runner 8. There is. In this case, the runner axis a coincides with the mold axis (rotation axis).

The arrangement structure of the cavity 9 is as follows. That is, as shown in FIGS. 3 and 4, eight cavities 9 whose axes are located on one horizontal plane are radially arranged at intervals of 45 ° about the runner axis a. Further, when eight cavities 9 arranged radially are regarded as one cavity group G, a plurality of, for example, four cavity groups G are arranged in a plurality of stages along the runner axis a, four stages in the illustrated example. ing. In this case, the eight cavities 9 in the two adjacent cavity groups G are in a relationship of overlapping each other in the direction of the runner axis a. The total number of cavities 9 is 32.

The mold 7 has a plurality of, in the illustrated example, eight mold-matching surfaces b. The mold-matching surfaces b have the same length as the generatrix length of the mold 7, and the runner axis a is the center. In the illustrated example, each of the four cavities 9 aligned radially in the direction of the runner axis a is bisected by radially extending from the runner axis a at intervals of 45 °. As a result, the mold 7 is divided into a plurality of mold structures (e.g., eight mold structures) 11 having the same structure.

As shown in FIG. 5, each mold assembly 11 is composed of a main body 12 having a substantially fan-shaped plane, and a protrusion 13 having a substantially triangular plane that protrudes radially inward at the lower end of the main body 12. The main body 11 has both side surfaces c forming a mating surface b.
Each has four cavity halves 9a. The runner 8 is formed by the uneven inner peripheral surface d of the entire main body 12, and the bottom wall 14 of the runner 8 is formed by each protrusion 13.

The lower end side of each mold structure 11 is fixed to the rotary disk 5 with bolts 17 and nuts 18 at the bottom wall 16 of the recess 15 opening to the outer peripheral surface thereof. Further, a cap member 19 is fitted on the upper end side of each of the mold constituents 11, and the cap member 19 is provided for each of the mold constituents 11.
Then, the upper wall 20 of the recess 15 is fixed by the bolt 21. A sprue 22 is formed at the center of the cap member 19, and the sprue 22 communicates with the runner 8.

The device 2 is provided with the following water cooling mechanism W utilizing the rotary shaft 3. That is, the rotary shaft 3 is formed in a hollow shape, and the upper end side of the hole 23 is closed by the center of the lower surface of the rotary disk 5. A non-rotating tube 24 is loosely inserted into the hole 23 with its upper opening close to the center of the lower surface of the turntable 5, and the water conduit e between the tube 24 outer peripheral surface and the hole 23 inner peripheral surface. Also, the inside of the pipe 24 functions as a drainage channel f.

Next, a concrete casting example of the pin-shaped casting 1 will be described.

The inner diameter of each cavity 9 is 25
mm, and the length was set to 70 mm, and the high-frequency induction furnace equipped with the mold 7 and the water-cooled copper crucible was both installed in the decompression chamber. Further, as the TiAl-based intermetallic compound, a compound having an Al content of 48 atomic% and the balance of Ti and inevitable impurities was prepared. (A) About 8 kg of TiAl-based intermetallic compound was put into a water-cooled copper crucible, and then the air pressure in the decompression chamber was set to about 10 ⁻³ To.
The pressure is reduced to rr, and then Ar is evaporated to prevent evaporation of the Al component.
The inside of the decompression chamber was replaced with gas to 200 Torr. (B) Induction melting was performed under the condition that the melting output was 125 kW and the material was melted down and then held for 5 minutes to prepare a molten metal having a TiAl-based intermetallic compound composition. (C) Cooling water is made to flow from the water conduit e to the drainage channel f to cool the mold 7 through the rotating disk 5, and the mold 7 is rotated at 800 rpm to obtain a molten metal temperature of about 1600 ° C. and about 6 kg of molten metal. The spout 2
A casting body CA in which 32 pin-shaped castings 1 are projected onto the outer periphery of the cylindrical scrap s by the runner 8 as shown in FIG. 6 by injecting from 2 into the runner 8 and rotating the die 7 for 4 minutes as it is. Got (D) The cast body CA was left as it was for 30 minutes after the rotation of the die 7 was stopped, and then the decompression chamber was opened to the atmosphere, and then the cast body CA was released from the die 7. In this mold release, the cap member 19 is removed from the mold 7, and the bolts 17 and the nuts 18 of the mold structures 11 are removed to move the mold structures 11 in the radial direction as shown in FIG. Pull it out. In this case, since the mold 7 is divided into eight, the drawing resistance for each mold structure 11 is small.
By setting the drawing directions of the mold structures 11 in the same direction in this way, the mold releasing process can be easily automated.

All pin-shaped castings 1 from tubular scrap s
Was cut, and the dimensions of each pin-shaped casting 1 were examined. The diameter was 25 mm over the entire length and there was no deviation of the axis line. Therefore, each pin-shaped casting 1 had good dimensional accuracy. Was found to have.

This is for the following reason. That is, since each mold structure 11 has four cavity halves 9a on both side surfaces c forming the mold matching surface b, the thermal conditions during casting are different from each other on both side surfaces of each mold structure 11. They are substantially the same on the c side, so that the two adjacent mold structures 11 are adjacent to each other.
This is because the positional deviation between the two cavity halves 9a is prevented.

When the casting operation was repeated 20 times, the mold 7 was discolored. The strength of the mold 7 was examined. The tensile strength of the pure copper before casting, that is, the die 7 was about 450 MPa, but since the die 7 was heated during casting, the die 7 was annealed by 20 casting operations. The tensile strength had dropped to about 230 MPa.

After that, when the same casting operation as described above was repeated, it was found that the tensile strength of the die 7 was maintained at about 230 MPa. This is as described above for each mold assembly 1
This is because there is almost no deformation of the mold 1 due to heat and the drawing resistance thereof is small, so damage to the die 7 due to the heat and drawing is avoided.

As described above, in the copper alloy turntable 5, if the pure copper mold 7 is installed on the upper surface side and the water cooling mechanism W is attached on the lower surface side, the heat dissipation of the mold 7 is good. Therefore, the total volume of the mold structure 11 (that is, the total volume of the metal portion) can be reduced without changing the total volume of the cavity 9 (that is, the total volume of the space) to reduce the size and weight of the mold 7. You can For example, the total volume of the mold structure 11 can be reduced to about two-thirds of the case where the steel turntable 5 is used and the water cooling mechanism W is not provided.

The pin-shaped casting 1 is used, for example, as a piston pin material for engines. Further, the mold 7 may have only one cavity group G.

FIG. 8 shows a plate-shaped casting 2 having eight rectangular shapes.
The case where a large number of 5 are taken is shown. Plate castings 25
Has one long side continuously provided on the outer peripheral surface of the cylindrical scrap s, and projects radially from the outer peripheral surface.

The present invention is also applied to a mold for obtaining such a cast body CA. In this case, the mold has one cavity group G.

When each cavity is divided into two halves by a die-matching surface that intersects with the runner axis as in the conventional die, when a large number of plate-shaped castings 25 as described above are taken, each cavity has its own shape. Since one short side is communicated with the runner through the gate, the diameter of the mold becomes large and inevitably increases in size. According to the present invention, one long side of each cavity can be directly communicated with the runner, so that the diameter of the mold can be significantly reduced and the size thereof can be reduced. Further, the drawing resistance for each mold structure is smaller than that in the case of the pin-shaped casting 1, and therefore the mold life is extended.

The plate-shaped casting 25 is used as a material for cutting a blade or the like.

As the constituent material of the die 7, in addition to the pure copper, various copper alloys, various steel materials (JISSS material, SCM material,
SK material, SKD material, etc.) are used. A graphite mold is also applicable.

Further, in the mold 7, each mold matching surface b may extend radially from the inner peripheral surface of the runner 8. Furthermore, the multi-cavity casting mold according to the present invention is not limited to the vertical centrifugal casting method,
It also applies to other casting methods, for example gravity casting.

[0029]

EFFECTS OF THE INVENTION According to the present invention, a multi-cavity casting mold capable of obtaining a plurality of castings having good and constant dimensional accuracy can be provided by the above-mentioned structure. .

[Brief description of drawings]

FIG. 1 is a perspective view of a pin-shaped casting.

FIG. 2 is a plan view of a vertical centrifugal casting device.

FIG. 3 is a sectional view taken along line 3-3 of FIGS.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is a perspective view of a mold structure.

FIG. 6 is a cross-sectional view corresponding to FIG. 3 after casting.

7 is a sectional view taken along line 7-7 of FIG. 6 and corresponds to FIG.

FIG. 8 is a perspective view showing another example of a cast body.

[Explanation of symbols]

 7 Mold (mold) 8 Runner 9 Cavity a Runner axis b Mold matching surface G Cavity group

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshio Tokune 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. No. Stock Company Honda Technical Research Institute

Claims (3)

[Claims] 1. A cylindrical runner (8) and its runner (8)
And a plurality of casting cavities (9) arranged radially around the runner axis (a) and in a radial pattern centered around the runner axis (a). A multi-cavity casting mold characterized in that it has a plurality of mating surfaces (b) which are arranged to divide each cavity (9) into two. 2. When the plurality of radially arranged casting molding cavities (9) is one cavity group (G), the plurality of cavity groups (G) extend along the runner axis (a). The multi-cavity casting mold according to claim 1, which is arranged in a plurality of stages. 3. The multi-cavity casting mold according to claim 1, which is a vertical centrifugal casting mold (7) having the runner axis line (a) as a rotation axis line.