JPS63242458A - Casting apparatus - Google Patents

Abstract

PURPOSE:To efficiently and sufficiently vent gas and to improve the quality of a casting by arranging supplementary gas vent hole besides gas vent passage and executing gas vent in a cavity by working suction mechanism together with them. CONSTITUTION:The cavity C in a mold M is formed by an upper mold 10, side molds 111, 112, lower mold 12, sand core 16, core print 16 and core bedding frame 18. This cavity C is communicated with an overflow part 20 connecting with the gas vent passage P at the upper part thereof and the runner 19 is shaped at the lower part thereof and the gas vent passage P is connected with the suction mechanism 26. Further, in roof face forming part 10a in the cavity in the mold M, plural hole parts 28 are formed and the gas vent pin 29 is arranged in each hole part. By this constitution, molten metal is poured into the cavity C and the gas vent is executed through each overflow part 20 and gas vent passage P. At the time of cutting off the gas exhaust passage P by filling up the molten metal into the overflow part 20, gas in the cavity C is vented from the gas vent hole arranging in the pin 29 in the hole part 28, and this gas vent hole is clogged by solidification following to invasion of the molten metal.

Description

Detailed Description of the Invention A0 Objectives of the Invention Tl) Industrial Field of Application The present invention relates to a casting apparatus, in particular, to a casting apparatus, in which the lower part of the cavity of the mold is connected to a runner, and the upper part of the cavity is connected to an overflow part connected to a gas venting passage. The present invention relates to an improvement in which the degassing passage is shut off after the overflow portion is filled with molten metal.

(2) Prior Art Conventionally, as a casting device of this type, one is known in which degassing is performed by natural ventilation through a degassing passage whose upper end is open to the atmosphere (Japanese Patent Application Laid-Open No. 102365-1985).
(see publication).

(3) Problems to be solved by the invention However, when degassing is performed only by natural ventilation as described above, gas tends to remain in the cavity due to poor degassing efficiency, and in addition, the degassing passage is blocked. Thereafter, the gas originally contained in the molten metal, the gas generated from the sand core, etc. cannot be removed, and as a result, the gas accumulates in the upper part of the cavity, which hinders the improvement of casting quality.

An object of the present invention is to provide the casting apparatus that can solve the above problems.

B0 Structure of the Invention (1) Means for Solving the Problems The present invention provides an air intake mechanism connected to the gas venting passage, and an air intake mechanism connected to the air intake mechanism and connected to the cavity ceiling surface forming part of the mold. It is characterized by having an auxiliary gas vent hole that opens at the bottom and closes when the molten metal enters and then solidifies.

(2) Effect With the above structure, the gas in the cavity is forcibly discharged mainly through the gas vent passage by the intake mechanism until the overflow part is filled with molten metal.

Further, after the gas vent passage is shut off, the gas in the cavity is forcibly discharged by the intake mechanism via the auxiliary gas vent hole.

Since gas is vented efficiently in this way, the accumulation of gas in the upper part of the cavity is suppressed as much as possible.

When the molten metal enters the auxiliary gas vent hole, the molten metal is cooled and solidified by the hole wall, so the auxiliary gas vent hole is sealed and no pressure leakage occurs during the subsequent molten metal pressurization step.

(3) Example 1. FIG. 2 shows a Siamese type cylinder block S, which consists of a cylinder block body 1 made of aluminum alloy and a sleeve 2 made of cast iron. The cylinder block main body 1 has a plurality of cylinder barrels 31 to 3, and the illustrated example has four cylinder barrels 31 to 3.
4, a cylinder block outer wall 4 surrounding the Siamese cylinder barrel 3, and a crankcase 5 connected to their lower edges. A water jacket q facing the outer periphery of the Siamese cylinder barrel 3 is formed between the Siamese cylinder buntle 3 and the cylinder block outer wall 4, and at the cylinder head side end of the water jacket 6, each cylinder barrel 31 to 34 and the cylinder block outer wall 4 are exposed. The spaces are partially connected by a plurality of reinforcing deck parts 7 arranged in the circumferential direction, and the space between adjacent reinforcing deck parts 7 functions as a communication port 8 to the cylinder head side of the water jacket 6. As a result, the cylinder block S is configured into a closed deck type. The sleeve 2 is attached to each cylinder barrel 3, -3. The sleeve 2 defines a cylinder pore 9.

FIG. 3 shows a casting apparatus for the cylinder block S, in which a plurality of molds (two molds are shown in the figure) are arranged such as an upper mold 10 that can be raised and lowered, and a plurality of molds (two molds are shown in the figure). ), and each side mold 11.
．． A cylinder block molding cavity C is defined by these molds 10 to 12.

A first molding part 141 for molding the crank pin and crank arm rotation space 13 (FIG. 2) on the lower mold 12.
and crank journal bearing holder 15 (Fig. 2)
A second molding section 14z for molding is provided. First molding section 14. is each cylinder barrel 3. ~ 34, and the second molded part 14
．． It is arranged on the outside of the molded part 14 of both cylinders 1 and the outermost part.

Sleeves 2 are erected on the top surface of the first molded part 14+, and sand cores 16 for water jackets are opposed to each other via a plurality of baseboards 17 and a plurality of core holders 18 so as to surround each sleeve 2. It is held between the molds 111 and 11□ on both sides. The sand core 16 is molded using shell sand.

Each side mold 11+, 11g and the lower mold 12 define a pair of runners 19 that communicate with the lower part of the cavity C, and the upper mold 10 and each side mold 111.11t define a pair of runners 19 that communicate with the upper part of the cavity C. A plurality of overflow sections 20 are defined.

The upper mold 10 is placed with the axis directed in the vertical direction and the upper end exposed to the atmosphere.
Further, pin holes 21 are formed whose lower ends are opened in the ceiling surface of each overflow part 20, and each pin hole 21 has a large diameter part 21a on the atmosphere side and a small diameter part 21b on the overflow part 20 side.

A seal pin 22 that can tightly fit into the small diameter portion 21b of each pin hole 21 is inserted into each pin hole 21, and the upper end of each seal pin 22 is connected to a lifting cylinder (not shown) via a connecting plate 23.

Also, in the upper mold 10, one end is attached to the small diameter part 21b of the pin hole 21,
Further, through holes 25 are formed, the other end of which communicates with the inlet 24a of the manifold 24 fixed to the upper surface of the upper mold 10.
An outlet 24b of the manifold 24 is connected to an intake mechanism 26 such as an intake pump via a pipe 27. Thereby, the small diameter portion 21b, the through hole 25, and the through hole 24c of the manifold 24 constitute a gas vent passage P.

In the upper mold 10, in the cavity ceiling surface forming part 10a,
A plurality of holes 28 are formed with their axes facing in the vertical direction and opening their lower ends into the cavity C, and a gas vent pin 29 is attached to each hole 28 . Each gas vent pin 29 includes an upper male threaded portion 29a, a lower large diameter portion 29b, and a small diameter portion 29C existing therebetween. As clearly shown in FIG. 4, a plurality of grooves 30 extending over the entire length in the generatrix direction are formed on the outer peripheral surface of the large diameter portion 29b, and the inner surface of each groove 30 cooperates with the inner peripheral surface of the hole 28 to form a cavity C. An auxiliary gas vent hole H is defined. Each auxiliary gas vent hole H communicates with the gas vent passage P via the gap g between the small diameter portion 29c and the hole 28 and the plurality of communication holes 31.

Each auxiliary gas vent hole H is set to have a small cross-sectional area, so that when the molten metal enters and is cooled and solidified by the hole wall, it is closed by the solidified metal.

During casting, each seal pin 22 is raised as shown by the solid line in FIG. Inject molten aluminum alloy.

The gas in the cavity C is pushed up by the molten metal and is forcibly discharged mainly through the overflow portion 20 and the gas vent passage P by the intake mechanism 26. This degassing operation is performed until each overflow portion 20 is filled with molten metal.

After each overflow part 20 is filled with molten metal, the third
As shown by the chain lines in the figure, lower each seal pin 22 to open the through hole 2.
5 and the small diameter portion 21b, thereby blocking the gas vent passage P. Thereafter, the gas in the cavity C, that is, the gas originally contained in the molten metal and the gas generated by combustion of the resin in the sand core 16, is forcibly discharged by the intake mechanism 26 through each auxiliary gas vent H. Ru.

Since gas is vented efficiently in this way, it is possible to suppress the accumulation of gas in the upper part of the cavity C as much as possible, thereby improving the casting quality by avoiding the occurrence of casting defects caused by the accumulated gas. can.

When the molten metal enters each auxiliary gas vent hole H, the molten metal is cooled and solidified by the hole wall, so each auxiliary gas vent hole H is sealed with solidified metal, and pressure leaks in the subsequent molten metal pressurization process. As a result, the metal structure can be densified and a high-strength cylinder block S can be obtained.

C0 Effects of the Invention According to the present invention, the gas in the cavity can be efficiently and sufficiently discharged through the cooperation of the gas vent passage, the auxiliary gas vent hole, and the intake mechanism, thereby improving the casting quality. can.

Furthermore, the auxiliary gas vent hole and the suction mechanism can be easily attached to a ready-made device, which is effective in reducing equipment costs.

[Brief explanation of drawings]

FIG. 1 is a plan view of the main part of the cylinder block cut away, FIG. 2 is a sectional view taken along the line nm in FIG. Corresponding to FIG. 2, FIG. 4 is a sectional view taken along the line IV--IV in FIG. 3. C...Cavity, H...Auxiliary gas vent, M...
・Mold as mold, P... gas vent passage, 10a・
...Cavity ceiling surface forming part, 19...Runner, 20
... Overflow part, 26 ... At the time of intake mechanism Applicant: Honda Motor Co., Ltd. Agent Patent attorney Ochiai Key box Fig. 1 Fig. 2

Claims (1)

[Claims] In the casting apparatus, the lower part of the cavity of the mold is connected to a runner, and the upper part of the cavity is connected to an overflow part connected to a gas vent passage, and after the overflow part is filled with molten metal, the gas vent passage is shut off. A suction mechanism is connected to the gas vent passage, and an auxiliary gas vent hole is provided in the cavity ceiling surface forming part of the mold, which is connected to the suction mechanism, opens into the cavity, and is closed by solidification following entry of the molten metal. A casting device characterized by: