JPH1076350A - Manufacture of shell core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely discharge the unnecessary raw sand from a cavity of a die in manufacturing a shell core. SOLUTION: Raw sand 22 is blown from a blow head into a cavity 5 of a preheated die, and kept for the prescribed time to form a shell-shaped hardened layer 25 on an inner wall surface 24 of the cavity 5. When the shell- shaped hardened layer 25 is formed, a die 2 is turned by the prescribed angle, and stopped at the prescribed angle in oscillating the die 2 in each direction relative to the perpendicular plane B, and the non-hardened sand 22 is completely discharged outside from an opening 4 in the cavity 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a shell core, and more particularly to a method for discharging uncured raw material sand (hereinafter referred to as "uncured sand").

[0002]

2. Description of the Related Art As a method of manufacturing a shell core, raw material sand such as resin sand is blown into a cavity in a mold from the upper part of the mold, and the raw material sand is heated to form a shell-like hardened layer on the inner wall surface of the cavity. After forming, the mold is inverted, and the mold is swung right and left at a predetermined swing angle with the center axis as a fulcrum. There is a method of discharging (described in Japanese Patent Publication No. 6-61595).

[0003]

However, in the case of a shell core having a complicated shape, the uncured sand is completely discharged from the mold only by swinging the mold left and right as described above. Is difficult. Then, this invention is made in order to solve the said problem, and makes it a subject to provide the manufacturing method of the shell core which discharges unhardened sand completely from a metal mold | die.

[0004]

According to the method of manufacturing a shell core of the present invention, raw material sand is blown into a cavity in a mold, and the raw material sand is heated to form a shell-like hardened layer on the inner wall surface of the cavity. Then, in the method of manufacturing a shell core for discharging the uncured raw material sand by swinging the mold around the horizontal center axis of the mold, the mold is fixed to a predetermined position during the swing. It is characterized by stopping at an angle.

[0005] During the swinging of the mold, the mold is stopped at a predetermined angle according to the shape of the shell core. Is discharged from the mold.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The angle at which the mold is stopped during swinging can be arbitrarily set according to the shape of the shell core, and when the shape of the shell core is complicated, the die is stopped a plurality of times at various angles.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an apparatus for manufacturing a shell core used in this embodiment. The mold 1 includes a fixed mold 2 and a movable mold 3, and a cavity 5 having an opening 4 is formed from the fixed mold 2 and the movable mold 3. A gas burner 9 is fixed to the back surfaces 6 and 7 of the two dies 2 and 3. The gas burner 9 is connected to a gas supply line (not shown), and a plurality of nozzles 8 are directed toward the back surfaces 6 and 7. It is arranged. The fixed die 2 is fixed to a fixed die base 11 via a connecting member 10, and the fixed die base 11 has a horizontal center axis A of the die 2.
A rotation shaft 13 of a motor 12 having a rotation center on the top and capable of arbitrarily controlling a rotation speed, a rotation direction, and a rotation angle by a control device (not shown) is connected. The movable mold 3 is fixed to the movable die base 15 via the connecting member 14,
The movable die base 15 includes a fixed die base 11 and an end plate 16 provided to face the fixed die base 11.
Is slidably mounted on a guide bar 17 laid between the guide bars 17. A drum 19 having a cylinder device 18 is rotatably mounted on a roller 20 on the end plate 16, and a cylinder rod 21 of the cylinder device 18 is fixed to the movable die base 15. A blow head 23 that blows raw material sand 22 such as resin sand from the opening 4 of the cavity 5 into the cavity 5 is disposed above the mold 1.

Next, a method of manufacturing a shell core will be described. The fixed mold 2 and the movable mold 3 are preliminarily heated by the flame ejected from the nozzle 8 of the gas burner 9, and the cylinder rod 21 of the cylinder device 18 is advanced in a state where both the molds 2 and 3 are heated to a predetermined temperature ( 1 (left direction in FIG. 1), the movable mold 3 and the fixed mold 2 are matched to form the cavity 5, and the raw material sand 22 is blown into the cavity 5 from the blow head 23. As shown in FIG. 2, the raw material 22 is filled in the cavity 5 and held for a predetermined time, and a shell-like hardened layer 25 is formed on the inner wall surface 24 of the cavity 5 as shown in FIG. 3. When the shell-shaped cured layer 25 is formed, the motor 12 is driven to rotate the mold 2 together with the stationary die base 11 by a predetermined angle, and then the mold 2 is swung in both directions with respect to the vertical plane. At this time, as shown in FIGS. 4 and 5, the mold 1 is stopped at a position where the vertical center axis C of the mold 1 is inclined at an angle α with respect to the vertical plane B, and the state is maintained for a predetermined time. The uncured raw material sand 22 remaining in the mold 5 is discharged.
And the mold 1 is stopped again at a position where the vertical center axis C is inclined at an angle α on the target side with respect to the vertical plane B, and the mold 1 is kept in that state for a predetermined time, and the raw material that has not been completely discharged earlier The sand 22 is discharged. The angle α is, for example, an angle at which the inner wall surface 24 of the cavity 5 on the front side (indicated by an arrow in FIGS. 4 and 5) in the swing direction of the mold 1 becomes larger than the repose angle of the raw material sand 22 with respect to the horizontal plane. The mold 1 is repeatedly swung and stopped as necessary, and the raw material sand 22 in the mold 1 is completely discharged from the mold 1.

After the uncured raw material sand 22 has been discharged,
The mold 1 is returned to the position where the raw material sand 22 was blown, and further heated for a predetermined time to complete the hardening of the shell-shaped hardened layer 25, and then the cylinder device 18 is driven to retract the cylinder rod 21 (FIG. 1). When the movable mold 3 and the fixed mold 2 are separated from each other, a shell core having a uniform thickness and free from partial curing failure can be obtained.

[0010]

According to the present invention, the raw material sand is blown into the cavity in the mold, and the raw material sand is heated to form a shell-like hardened layer on the inner wall surface of the cavity. In a method for manufacturing a shell core that discharges uncured raw material sand by swinging about a horizontal center axis of a mold, the shell core is stopped at a predetermined angle during the swing. The mold can be stopped at the angle at which the uncured sand is most easily discharged to the shape. Therefore, even when the shell core shape is complicated, the uncured sand can be completely discharged, and the core sand can be efficiently collected and reused. In addition, in the case of molding, when the curing is completed by reheating after discharging the uncured sand, there is no occurrence of a curing failure portion of the shell core due to the remaining uncured sand, and the thickness of the shell core to be molded is reduced. It becomes uniform and the incidence of defective products is reduced.

[Brief description of the drawings]

FIG. 1 is a front view of an apparatus used for a method of manufacturing a shell core according to the present invention.

FIG. 2 is a view showing a mating surface of a fixed mold filled with casting sand.

FIG. 3 is a view showing a fixed type mating surface in a state where a shell-like hardened layer is formed on an inner wall surface.

FIG. 4 is a view showing a state where the fixed mold of FIG. 3 is swung.

FIG. 5 is a view showing a state where the fixed mold of FIG. 3 is swung in a direction different from that of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 5 Cavity 22 Raw material sand 24 Inner wall surface 25 Shell-shaped hardened layer

Claims (1)

[Claims] 1. A raw material sand is blown into a cavity in a mold,
After heating the raw material sand to form a shell-like hardened layer on the inner wall surface of the cavity, the mold is swung about the horizontal center axis of the mold to discharge the uncured raw material sand. A method for manufacturing a shell core, comprising: stopping the mold at a predetermined angle during the swinging.