JPH05305386A - Manufacture of hollow core - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for a hollow core having a necessary and sufficient thickness by surely sticking sand to hole wall at the time of injecting the molding sand to a hollow die hole. CONSTITUTION:In this manufacturing method for the hollow core, one pair of divided dies 1a, 1b are mutually fitted and thereafter, the molding sand is injected into the hollow die hole 2 formed with both divided dies 1a, 1b, and by heating both divided dies 1a, 1b, the molding sand at the part in contact to the hole wall in hollow die hole 2 is hardened and also, uncured molding sand filled up at a position being apart from the hole wall is forcedly pushed out to the outside. Then, at the time of mutually fitting one pair of the divided dies 1a, 1b, or injecting the molding sand or heating the molding sand, on at least the outer peripheral surface of both divided dies 1a, 1b corresponding to the mutually fitting part of both divided dies 1a, 1b, the sucking means 18 is closely added so as to be freely contact/uncontact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a hollow core for casting, and more particularly, the present invention is a method in which a pair of split molds are anastomosed with each other to form a mold sand in a hollow mold hole formed by the split molds. The mold sand in the portion of the hollow mold hole that is in contact with the hole wall is hardened by heating both molds, and the uncured mold sand that is filled in at a position away from the hole wall is forced out to the outside and hollow A method of manufacturing a child.

[0002]

2. Description of the Related Art As a conventional hollow core manufacturing method of this type, there is one already proposed by the same applicant as the present invention. That is, this is the method disclosed in Japanese Utility Model Laid-Open No. 3-85149, in which the mold sand in the tank is connected to the mold sand supply / discharge port of the divided mold, and the hollow mold hole of the divided mold is used. An air supply pump for injecting into the inside and an air suction pump for sucking and discharging the mold sand in the hollow mold hole to the tank are selectively connected and communicated via a switching valve, and After anastomosis of both split molds,
The mold sand inlet / outlet of the tank is connected to the mold sand supply / discharge port, the air supply pump side is connected to the tank, and the mold sand in the tank is blown and filled into the hollow mold holes of the two heated divided molds. After a lapse of a predetermined time, the air suction pump side is connected to the tank, and the uncured mold sand in the hollow mold cavity is sucked and discharged into the tank, whereby the heat-cured hollow core is placed in the hollow mold cavity. Form.

[0003]

In the above-described conventional core manufacturing method, when the mold sand is blown and filled into the hollow mold holes of both split molds from the mold sand supply / discharge port, the mold sand is supplied into the hollow mold holes. The pressure air escapes to some extent from the gap between the anastomosis parts of the two split molds, but since the gap in the anastomosis part is a minute gap, most of the supplied air is temporary. Remains in the hollow mold cavity, and as a result, sand does not adhere sufficiently to the hole wall in the recessed part of the hollow mold cavity, especially in the downward hole wall part of that part. The thickness of the part of the child may be thinner than the desired thickness, or in some cases, the meat may not be attached,
It was one of the causes of defective products.

In view of the above problems, the present invention ensures that the sand is adhered to the hole wall when the mold sand is injected into the hollow mold hole to manufacture a hollow core having a necessary and sufficient wall thickness. The purpose is to provide a possible method.

[0005]

According to the method of the present invention, at least both split molds 1 are provided at the time when a pair of split molds 1a and 1b are anastomosed with each other, or when the mold sand is injected or the mold sand is heated.
Both split molds 1a corresponding to the anastomotic part of a and 1b,
It is characterized in that the suction means 18 is attached to the outer peripheral surface of 1b so as to be releasably in close contact therewith.

[0006]

EXAMPLES Examples will be described with reference to the drawings.
FIG. 1 shows a hollow core manufacturing apparatus for carrying out the present invention. In this figure, 1 is a mold, which is divided into a fixed mold 1a and a movable mold 1b. ，
The hollow mold cavity 2 is formed by 1b. The fixed mold 1a is fixed to the one fixed frame 4 side through the support member 3, and the movable mold 1b is slidable along a guide bar 6 which is horizontally stretched between the fixed frames 4 and 5. The fluid pressure cylinder 8 is attached and fixed to the support member 7 and is pressed between the support member 7 and the other fixed frame 5 so as to be anastomosed with respect to the fixed mold 1a. Or they are separated.

A mold sand feeder 9 which is movable along a guide rail 11 of an apparatus base 10 is provided below the mold 1, and the mold sand feeder 9 has a mold sand tank portion 12 which can be moved up and down. , The mold sand receiving portion 12a of the mold sand tank portion 12
The mold sand is supplied to the hollow mold hole 2 through the mold sand supply / discharge port 13 of the mold 1, and the mold sand sucked and discharged from the hollow mold hole 2 is received in the tank portion 12. Although not shown, the inside of the mold sand tank portion 12 is divided into an upper mold sand storage chamber and a lower airtight chamber by a filter made of wire mesh or the like. A switch for connecting the supply pump 15 and the air suction pump 16 and selectively connecting one of the air supply pump 15 and the air suction pump 16 to the airtight chamber in the middle of the air hose 14. A valve device 17 is provided.

Above the mold 1, both split molds 1a,
A suction means 18 is provided which can be closely attached along the outer peripheral surface of both split molds 1a and 1b corresponding to the anastomosis portion of 1b (each anastomosis surface is indicated by F in the figure). As shown in FIGS. 1 and 2, this suction means 18 is a flat plate 19 made of metal.
Band-shaped rubber-like elastic body 20 having heat resistance around the lower surface peripheral portion
2. A suction body 2 in which a suction chamber 21 is formed by fixing and arranging in a peripheral frame shape.
2, an end portion of an air hose 23 communicating with the suction chamber 21 is connected to the suction member 22, and the other end portion is connected to a required air suction pump (not shown). The suction body 22 is interlockingly connected to a fluid pressure cylinder 24 installed at an appropriate position above the mold 1, and is moved up and down by driving the cylinder 24 to move the outer peripheral surfaces of the split molds 1a and 1b. Can be freely separated from and contacted with.

A method of manufacturing a hollow core using the apparatus having the above-described structure will be described. First, the movable mold 1b of the mold 1 is moved by driving the fluid pressure cylinder 8, and this movable mold is moved. While the mold 1b is anastomosed to the fixed mold 1a, the mold sand feeder 9 is moved to a position directly below the mold 1,
The mold sand tank portion 12 is raised as shown by the solid line in FIG. 1 so that the mold sand receiving portion 12a can communicate with the mold sand supply / discharge port 13 of the mold 1. Also, after the split molds 1a and 1b are anastomosed with each other, the molds 1a and 1b are heated by a required heating means. Then, the suction body 22 of the suction means 18 is lowered by the fluid pressure cylinder 24 and closely attached to the outer peripheral surfaces of the split molds 1a and 1b.
The air suction pump 8 is operated to start suction. With the start of suction by the suction means 18, both split molds 1a,
The air in the hollow mold hole 2 of 1b is sucked and discharged to the suction body 22 through the minute gap between the anastomotic surfaces F of the split molds 1a and 1b, and becomes a negative pressure state.

Next, by switching the switching valve device 17 to the side of the air supply pump 15, air is pressure-fed into the airtight chamber of the mold sand tank portion 12 via the air hose 14, and this pressure air causes the mold sand in the mold sand tank portion 12 to be blown. Is blown from the mold sand receiving portion 12a through the mold sand supply / discharge port 13 into the hollow mold hole 2 of the mold 1 heated to a predetermined temperature.
When the mold sand is injected into the hollow mold cavity 2 in this way, since the suction means 18 is sucking in the hollow mold cavity 2, the air supplied into the hollow mold cavity 2 together with the mold sand is As indicated by an arrow 2 in FIG. 2, the hollow mold hole 2 is discharged to the outside through a minute gap between the anastomotic surfaces F of the split molds 1a and 1b without remaining inside. Therefore, the mold sand injected into the hollow mold cavity 2 can surely and sufficiently adhere to the recessed part of the hollow mold cavity 2, especially the downward hole wall portion above the mold cavity 2.

However, when the switching valve device 17 is switched to the air suction pump 16 side after a lapse of a predetermined time, the inside of the mold sand tank portion 12 is in a negative pressure state, and the hollow mold hole 2 is separated from the hole wall. The non-hardened mold sand that has been filled is sucked and discharged into the mold sand tank portion 12, and the hollow mold hole 2 is filled with the heat-hardened mold sand that is filled in the portion in contact with the hole wall of the hollow mold hole 2. A hollow core M as shown in 3 is formed. As is clear from FIG. 3, the core M has a sufficiently large wall thickness in the portion m formed by the downward hole wall portion above the hollow die hole 2. It is preferable that the operation of the suction means 18 is continued during the suction and discharge of the mold sand from the hollow mold hole 2.

When the hollow core M is formed in this way, the operation of the air suction pump 16 is stopped, the operation of the suction means 18 is stopped, and the mold sand tank portion of the mold sand supply device 9 is stopped. After lowering 12, the mold sand supply device 9 is moved to a predetermined position, and the suction body 22 of the suction means 18 is raised to be separated from both split molds 1a and 1b, and the movable mold 1b is fixed. The hollow core M is taken out from the mold 1a.

FIG. 4 shows the hollow core Mo manufactured without using the suction means 18, in comparison with the hollow core M of FIG. 3, and as will be apparent by referring to both, the suction means When 18 is not used, the thickness of the mold sand is insufficient at the portion m formed by the downward hole wall of the upper part of the hollow mold hole 2, and the wall thickness is thin and sluggish.

In the embodiment described above, the suction means 18 is applied only to the upper wall surface side of the split molds 1a and 1b.
As shown by the phantom line, it is more effective if the similar suction means 18 is applied to both side wall surfaces of both split molds 1a and 1b. Of course, the entire outer peripheral surface of both split molds 1a, 1b corresponding to the anastomosis portion of both split molds 1a, 1b, including the lower wall surface side of both split molds 1a, 1b, and further a normal mold It is even more effective if it is applied to an air vent hole provided.

Further, the suction by the suction means 18 may be started at the time of anastomosing the two split molds 1a and 1b, or after the split molds 1a and 1b are anastomosed, the mold sand is hollowed into the hollow mold cavity 2 It may be from the time of injecting into the mold or from the time of heating the mold 1 before injecting the mold sand. Further, the suction means is not limited to the structure shown in the embodiment, but other suitable structure can be adopted.

[0016]

According to the method and effect of the present invention, at the time when a pair of split molds are anastomosed with each other, or when the mold sand is injected or the mold sand is heated, at least both split molds corresponding to the anastomosis portion of each other are split. By bringing suction means into close contact with the outer peripheral surface of the mold to perform suction operation, the inside of the hollow mold cavity is in a negative pressure state. Then, when the mold sand is injected into the hollow mold cavity in such a state, the air supplied together with the mold sand into the hollow mold cavity is discharged to the outside at least from the minute gap between the anastomotic surfaces of the split molds. It does not remain in the hollow mold cavity. As a result, the mold sand injected into the hollow mold hole can surely and sufficiently adhere to the recessed part of the hollow mold hole, particularly even on the downward hole wall part of the hollow mold hole, and therefore, the desired sand required. It is possible to manufacture a good quality hollow core having a wall thickness.

[Brief description of drawings]

FIG. 1 is an overall schematic front view of an apparatus for carrying out the method of the present invention.

FIG. 2 is an enlarged cross-sectional view taken along the line AA in FIG. 1, showing a state where mold sand is injected into the hollow mold holes of both split molds.

FIG. 3 is a sectional view similar to FIG. 2, showing a state in which a hollow core is formed.

FIG. 4 is a sectional view similar to FIG. 3, showing a hollow core manufactured without using the suction means of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 1a Divided mold 1b Divided mold F Anatomized surface of split mold 2 Hollow mold hole 13 Sand feeding / discharging port 18 Suction means

Claims (1)

[Claims] 1. A part in which a pair of split molds are anastomosed with each other, and then mold sand is injected into a hollow mold hole formed by both split molds, and the mold wall is heated to contact the hole wall of the hollow mold hole. In the method of manufacturing the hollow core by hardening the mold sand of No. 2 and forcibly sucking the uncured mold sand filled in the position apart from the hole wall to the outside, the time when the pair of split molds are anastomosed with each other or the mold sand At the time of injection or heating of the mold sand, at least the suction means is attached so as to be separably and closely attached to the outer peripheral surface of both split molds corresponding to the anastomosis portion of both molds. A method for producing a hollow core.