JPH0523793A - Core making machine - Google Patents

Abstract

PURPOSE:To prevent warp according to cooling of a core extruding from a metallic mold at the time of extrusion the hollow-state core with the metallic mold. CONSTITUTION:By pushing core sand S into inner part of the metallic mold 1 from one end of the heated metallic mold 1 with reciprocative movement of a piston 7, the hollow-state core W is formed, and the core W is extruded from the other end of metallic mold 1 according to the reciprocative movement of piston 7. The core W extruded from the metallic mold 1 is pushed into a cooling jig 13 and outer peripheral face of the core W is forcedly cooled with the cooling jig 13 while restricting this with cylindrical core guiding face 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core molding machine for molding a hollow rod-shaped core used for casting by a so-called extrusion molding method.

[0002]

2. Description of the Related Art As a core molding apparatus for molding a hollow rod-shaped sand core, there is, for example, a structure shown in FIGS.

In this core molding apparatus, a mold 1 heated by a heater 2, a cylinder 3 adjacent to one end of the mold 1 and a hopper 4 connected to the upper portion of the cylinder 3 are provided.
The hopper 4 has a predetermined core sand S.
On the other hand, the piston 7 having the core portion 6 is inserted into the space 5 of the cylinder 3.

As a molding procedure for the core W, first, the shutter 8 provided on the hopper 4 is opened to drop a predetermined amount of the core sand S in the hopper 4 into the cylinder 3 to fill it, After the shutter 8 is closed, the piston 7 is advanced to push the core sand S in the cylinder 3 into the mold 1 as shown in FIG.

The core sand S pushed into the mold 1 is the mold 1
Is formed into a hollow cylindrical shape by the cylindrical surface 9 and the core portion 6 of
Finally, by filling the core sand S into the cylinder 3 and moving the piston 7 forward and backward as described above, a long hollow rod-shaped core W is formed.

Since the core sand S contains a resin in advance, the core W is heated and hardened in the process of passing through the mold 1, and the molded core W reciprocates the piston 7. It is gradually extruded from the other end of the mold 1 according to the movement.

The core W extruded from the mold 1 is a pedestal 10
It is supported by the semicircular guide surface 11 and is cut by the cutter 12 when the protruding length from the mold 1 reaches a predetermined length.

[0008]

In the conventional core molding apparatus as described above, for example, when sand for shell mold is used as the core sand S, the thermosetting resin is applied to the sand for shell mold itself. Therefore, the temperature of the mold 1 is set to 200 to 300 ° C.

Therefore, the temperature of the core W immediately after molding is 1
The temperature is about 50 to 200 ° C., and the core W is gradually cooled in the process of being transferred on the pedestal 10.
The core W on the pedestal 10 is merely supported by the semicircular guide surface 11 and is not particularly restricted in the radial direction. Therefore, the core sand S is pushed into the mold 1 by the piston 7.
Depending on the filling degree and the mold temperature, the core W is warped Q as shown in FIG. 4, and the accuracy of the shape of the core W cannot be improved.

The present invention has been made in view of the above problems, and provides a core molding apparatus in which warp of a core immediately after molding extruded from a mold is prevented to improve shape accuracy. With the goal.

[0011]

According to the present invention, a hollow core is formed by pushing core sand from one end of a heated mold into the inside of the mold by the reciprocating motion of a piston. In a core molding apparatus configured to push the core out of the other end of the mold in response to the reciprocating motion of the piston, the other end side of the mold has a cylindrical shape into which the core pressed out of the mold is inserted. It is characterized in that a cooling jig having a core guiding surface for forcibly cooling the core is provided.

A passage for passing a cooling medium is formed in the above cooling jig, and cooling water, compressed air, or the like is passed through this passage as a cooling medium.

[0013]

According to this structure, the core immediately after molding extruded from the mold is forcibly cooled in the process of passing through the cooling jig. At that time, the core is formed into the cylindrical shape of the cooling jig. Since the outer peripheral surface is cooled by the guide surface, it is possible to prevent the conventional warpage.

[0014]

1 (A) and 1 (B) are views showing an embodiment of the present invention, in which parts common to those in FIGS. 2 to 4 are designated by the same reference numerals.

As shown in FIGS. 1A and 1B, a cooling jig 13 is provided on the other end side of the mold 1 from which the core W is extruded and before the pedestal 10. There is. In this cooling jig 13, an upper die 14 and a lower die 15 are openably and closably coupled via a hinge pin 16, and the upper die 14 and the lower die 15 are clamped to form a cylindrical inner surface on the joining surface between them. The child guide surface 17 is formed, and the diameter of the core guide surface 17 is formed to be the same as that of the cylindrical surface 9 on the die 1 side.

A cooling passage 19 is connected to the upper mold 14 and the lower mold 15 of the cooling jig 13 by a pipe 18.
The cooling jig 13 itself is cooled by flowing a cooling medium such as cooling water or compressed air through the cooling passage 19.

In the core molding apparatus constructed as described above, the hollow core W molded by the mold 1 has a predetermined amount in accordance with the forward / backward movement of the piston 7 as in the conventional case.
Is extruded from the other end of.

A process in which the core W extruded from the mold 1 is immediately pushed into the core guide surface 17 of the cooling jig 13 and moves in the cooling jig 13 while the outer peripheral surface is constrained by the core guide surface 17. Is forcedly cooled by the cooling jig 13. At this time, the core W is rapidly cooled to near room temperature by the forced cooling of the cooling jig 13, but since the outer peripheral surface is constrained by the cylindrical core guide surface 17, the core W warps with cooling. Will not occur.

The core W cooled by the cooling jig 13 as described above contracts by a predetermined amount as it cools and is then pushed out from the other end of the cooling jig 13. Then, thereafter, as in the conventional case, the sheet is sent while being supported by the guide surface 11 of the pedestal 10 and then cut into a predetermined length.

[0020]

As described above, according to the present invention, the other end of the mold for molding the core has the cylindrical core guide surface through which the core for pushing out the mold is inserted. By providing a cooling jig for forcibly cooling the core, the outer peripheral surface of the core is constrained by the cylindrical core guide surface during the core cooling process. The core is not warped during the process, and the shape accuracy of the core is improved.

[Brief description of drawings]

1A and 1B are views showing an embodiment of the present invention, in which FIG. 1A is a sectional explanatory view thereof, and FIG. 1B is a sectional view taken along line aa in FIG. 1A.

FIG. 2 is a view showing an example of a conventional core molding device, and a cross-sectional explanatory view when a piston retracts.

FIG. 3 is a sectional view taken along line bb of FIG.

FIG. 4 is a view showing an example of a conventional core molding apparatus, which is a cross-sectional explanatory view when a piston advances.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mold 2 ... Heater 7 ... Piston 13 ... Cooling jig 17 ... Core guide surface 19 ... Cooling passage S ... Core sand W ... Core

Claims (1)

1. A hollow core is formed by pushing core sand from one end of a heated mold into the inside of the mold by reciprocating motion of a piston, and forming the molded core. In a core molding apparatus adapted to push out from the other end of the mold in response to the reciprocating motion of the piston, a cylindrical core into which a core pushed out from the mold is inserted, on the other end side of the mold. A core molding apparatus comprising a cooling jig having a guide surface for forcibly cooling the core.