JPS60106645A - Casting mold for high pressure solidification casting - Google Patents

Abstract

PURPOSE:To suppress the drop of molten metal temp. on the side of a mold cavity opposite from the sprue thereof in high-pressure solidification casting of a composite member by communicating a well part having the volume larger than the volume of a composite part with the other end in the longitudinal direction of the cavity. CONSTITUTION:A well part 5 having the volume three-times larger than the volume of a composite part is communicated with the end of a cavity 4 on the side opposite from a sprue 3 thereof. The melt of an Al alloy, etc. is supplied through the sprue 3 and is held under prescribed pressure. The drop of the melt temp. in the part 4b forming the small end of the cavity is suppressed in this stage by the holding effect of the part 5, by which the molten metal in the composite part (c) is thoroughly held. When the molten metal solidifies half, pressurizing punches 131-133 are actuated to act hydrostatic high pressure. The parts 4a, 4b forming the large end and small end and the well part 5 are locally pressurized and at the same time, the sprue 3 is pressurized by a plunger 12, by which secondary pressurization is accomplished. The molten metal is thoroughly filled and combined with a fiber molding F by such mold construction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure solidification casting mold used for casting fiber-reinforced composite members.

The present applicant has previously developed a mold of this type, which includes a sprue, a cavity having a composite part that communicates with the sprue at one end in the longitudinal direction and in which a reinforcing rod-shaped fiber molded body is installed in the middle part, and a mold that is filled into the cavity. has proposed a pressurizing member that pressurizes the molten metal under high hydrostatic pressure to fill and compose it into a fiber molded body (see Japanese Patent Application No. 173,687/1987).
In this mold, when the cavity is filled with molten metal from the sprue, the temperature of the molten metal on the opposite side of the cavity drops due to the long distance between the sprue and the composite part, making it impossible to keep the composite part warm enough. There is a problem that the filling composite properties of the fiber molded article deteriorate.

In view of the above, an object of the present invention is to provide a mold capable of suppressing a drop in hot water temperature on the side opposite to the sprue of the cavity, and to provide a sump portion communicating with the other end of the cavity in the longitudinal direction, The unique feature is that the volume of the hot water reservoir is set to be more than three times the volume of the composite part.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. Figure 2 shows a high-pressure solidification casting mold used for casting connecting rods for internal combustion engines whose frames are fiber-reinforced.
A sprue 3, a connecting rod molding cavity 4, and a sump 5 are formed sequentially from the left side in FIG. 1 by the mating surfaces of both molds 1.degree.2. The cavity 4 includes a large-volume large-end molded part 4a located at one longitudinal end, a small-volume small-end molded part 4b located at the other longitudinal end, and both parts 4α.
, 4b and a frame molded portion 4C having a small cross-sectional area. The volume ratio of the large end molded part 4a and the small end molded part 4b is usually about 4.5:1. The large end molded part 4α is the gate 6
1 to the sprue 3, and the small end molded portion 4b communicates to the sump 5 via the gate 62.

The lower die 1 is provided with a piston pin hole forming core 7 whose tip end extends into the small end molding portion 4h, and the core 7I
One end of a reinforcing rod-shaped fiber molded body F is press-fitted into a groove 8 formed at the tip end of the reinforcing rod-shaped fiber molded body F, and the cantilevered molded body F extends into the frame molded part 4C. Fiber molded body
・" is molded to a desired bulk density using long fibers such as metal fibers. Also, the lower mold 1 includes a core for forming a crank pin hole whose tip part extends into the large end molded part 4a. 72 is provided.

The volume of the pool 5 is the volume around the outer peripheral surface of the fiber molded body F, that is, the composite part C surrounding the entire length of the fiber molded body F including a part of the frame molded part 4C and the small end molded part 4z. The volume of 3~
It is set to 5 times or more.

A molten metal supply pipe 9 is connected to the sprue 3 so as to be inclined downwardly toward the sprue 3. A hopper 11 is attached to the molten metal supply pipe 9 so that molten metal can be supplied to the sprue 3 via the hopper 11 and the molten metal supply pipe 9. A seal granger 10 that seals the inside of the pipe 9 after supplying the molten metal to the sprue 3 is fitted onto the molten metal supply pipe 9 . The lower mold 1 is slidably provided with a plunger 12 whose tip extends into the sprue 3, and the upper mold 2 has its tip inserted into a large end molding section 4a, a small end molding section 4b, and a sump. Local pressure punches 131 to 133 inserted into the portions 5 are slidably provided. These granger 12 and local pressure punch 13. 133 functions as a pressure member.

When casting a connecting rod, after a molten metal such as an aluminum alloy is supplied to the sprue 3, the inside of the molten metal supply pipe 9 is sealed by a seal plunger 10. Next, the plunger 12 is raised to fill the cavity 4 and the sump 5 with the molten metal, and then the molten metal is primarily pressurized to a pressure of about 6ook/i. During this filling, the large end forming part 4a has a large amount of molten metal flowing in (the inflow speed is slow at 0.09 to 0.17φec, but the filling is done in a short time, and it is close to the sprue 3, Moreover, since the volume is large, a drop in hot water temperature is suppressed.Furthermore, in the frame forming part 4c, the cross-sectional area ratio is about 0.3 to the gate 6□ on the sprue 3 side, and the inflow velocity is 0.
．． Since the speed is as fast as 3 to 0.6 m/sec, filling can be done in a short time, which is convenient for suppressing the drop in water temperature. Furthermore, the heat retention effect of the molten metal reservoir 5 suppresses a drop in the temperature of the hot water in the small end molded part 4b, so that the molten metal in the composite part C can be sufficiently kept warm by the large end and small end molded parts 4α, 4b. I can do it. In this case, if the volume of the hot water reservoir section 5 is less than three times the volume of the composite section C, the above-mentioned heat retention effect cannot be expected.

The molten metal is held under the pressure for 1 to 10 seconds and when the molten metal becomes semi-solidified, the large end and small end forming portions 4a are applied with a pressure of 1000 to 2500 kg/7 by each local pressure punch 13° to 133. , 4b and the water reservoir 5 are locally pressurized, and at the same time, the plunger 12 is used to raise the pressure to 1000~'20.
0kl? /i to perform secondary pressurization by pressurizing the sprue 3, filling and compounding the molten metal into the fiber molded body F, and completely solidifying the molten metal under this pressurized state. After that, the cast body is released from the mold and subjected to a prescribed machining process. The connecting rod 14 shown in FIG. 4 is made of a large end portion 14a, a small end portion 14b, and a frame portion 14C that connects the two ends 14α and 14b and is reinforced with fibers, and the connecting rod 14 has excellent tensile, compressive and bending strength. It is something that

The mold of the present invention can also be applied to casting other relatively long casting bodies, such as rocker arms.

As described above, according to the present invention, by providing a sump with a specific volume on the side of the cavity opposite to the sprue,
The heat retaining effect of the hot water pool suppresses a drop in the temperature of the hot water in the composite part where the fiber molded body is installed, and the fiber molded body can be sufficiently filled with molten metal and composited.

[Brief explanation of the drawing]

1st. Fig. 2 shows an embodiment of the present invention, Fig. 1 is a longitudinal sectional front view, Fig. 2 is a view taken along the arrows - - Fig. 1, Fig. 3 is a plan view of the connecting rod, and Fig. 4 is a longitudinal sectional front view. FIG. 3 is a sectional view taken along the line IV-IV. C... Composite part, F... Fiber molded body, 1... Lower mold,
2... Upper mold, 3... Sprue, 4... Cavity, 5
. . . Reservoir portion, 12 . . . Plunger as a pressurizing member, 13. ~133...Local pressure punch as a pressure member

Claims (1)

[Claims] A sprue, a cavity having a composite part in which one end in the longitudinal direction communicates with the sprue and a reinforcing rod-shaped fiber molded body is installed in the middle part, and the molten metal filled in the cavity is pressurized with high hydrostatic pressure to In a high-pressure solidification casting mold equipped with a pressurizing member for filling and compounding a fiber molded body, a sump is provided at the other end in the longitudinal direction of the cavity and communicates with the sump, and the volume of the sump is set equal to the volume of the sump. A mold for high-pressure solidification casting, characterized in that the volume is set at least three times the volume of the mold.