JPS63220947A - Method and apparatus for molding green sand core - Google Patents

Abstract

PURPOSE:To obtain a core having uniform strength in thick part at center part and in thin part at rim part thereof by molding preformed body, of which upper half part has a enlarged size upward more than desired shape of the core, squeeze molding this pre-formed body into the desired shape of the core lower die. CONSTITUTION:A lower die 7 is ascended by extension of an upward cylinder 1 and a blowing die 12 is inserted into recessed part 6 in the lower die 7 and also the upper face of the lower die 7 is abutted on a stopper 16 and its ascent is stopped. By the recessed part 6 in the lower die 7 and a recessed part 11 in the blowing die 12, a pre-formed cavity, in which the upper half part is enlarged upward more than the desired shape of the core, is demarcated. Next, compressed air is supplied into a blow tank 10 and green sand is filled into the cavity to make the mold of pre-formed body. Successively, by descending the lower die 7, it is separated with the blowing die 12 and after positioning the squeezing die 26 between the lower die 7 and the blowing die 12 by extension of a sideward cylinder 34, the lower die 7 is ascended. The squeezing die 26 is inserted into the recessed part 6 in the lower die 7 and the pre-formed body is squeezed and the upper face of the lower die 7 is abutted on step part of the lower face in the squeezing die 26, to compress the pre-formed body into the desired shape of the core.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for molding green sand cores, and more specifically,
The present invention relates to a method and apparatus for molding green sand cores having different thicknesses in the center and periphery.

(Prior art) Cores are usually molded by shell molding, cold box method, CO2 method, etc. mainly for reasons of strength and dimensional accuracy. This mold is expensive and has different properties from the main mold made of green sand, so there are problems in the sand recycling process after pouring. For this reason, various methods of molding cores using the same green sand as the main mold have recently been attempted, and cores of relatively simple shapes that can be used for practical purposes have been molded. There is.

However, it has been difficult to mold a complex-shaped core with uniform strength and good dimensional accuracy.

(Object of the Invention) The present invention has been made in view of the above circumstances, and provides a green sand core with a complex shape that has uniform strength and good dimensional accuracy, especially in the center and peripheral parts. It is an object of the present invention to provide a method and an apparatus for molding green sand cores having shapes with different thicknesses.

(Example) Below, the configuration of an apparatus adapted to carry out the present invention will be explained with reference to FIG.
It is an upward-facing cylinder mounted upward, and the tip of its piston rod has a table (2) with a recess (2) on the top surface.
3) is fixed. Recess (2) of the table (3)
An upwardly facing extrusion cylinder (4) is installed in the
At the tip of the piston rod of the extrusion cylinder (4),
A connecting plate (5) is fixed. A lower mold (7) is mounted on the table (3), which has a recess (6) on its upper surface that has a shape corresponding to the shape of the lower half of the desired core, and a slight recess on its lower surface. There is. The recess (6)
A blow mold or a compression mold, which will be described later, is inserted into the core to define a preform cavity or a cavity corresponding to a desired core.

In the lower recess of the lower mold (7), an extrusion plate (9) having a plurality of extrusion bottles (8) planted on its upper surface is connected to the connection plate (5).
), and the extrusion pin (8) is provided so as to be able to penetrate through the lower mold (7) and retract from the bottom surface of the recess (6).

A blow tank (10) is arranged above the table (3) at an appropriate interval.
10) A blowing mold 12) having a recess (11) formed on the lower surface 1 side with a vertical dimension larger than the desired shape of the upper half of the core is installed on the lower surface of the lower mold (7). It is fixed to the recess (6) to form an external shape that can be slidably fitted into the recess (6). Furthermore, a sand blowing hole (13) is bored through the bottom plate of the blow tank (10) and the blowing die (12).

Note that (14>) is an exhaust hole that has one end opened around the lower surface of the blow mold (12) and the other end opened in the side wall of the blow mold (12), into which the vent plug (15) is fitted. has been done.

A stopper (
16) is fixed to surround the blowing mold (12), and the lower surface of the stopper (16) can come into contact with the outer periphery of the upper surface of the lower mold (7).

Furthermore, a roller conveyor (17) for transporting the green sand mold is arranged at an appropriate interval on the outside of the lower mold (7), and a surface plate ( A green sand main mold (20) with a frame (19) is placed through the mold (18).

Further, an upward cylinder (21) is disposed below the roller conveyor (17), and at the tip of the piston rod, a push-up plate ( 22) is fixed.

Furthermore, a position between the lower mold (7) and the blowing mold (12).

A hollow roller conveyor (23) is disposed above the push-up plate (22) in the roller conveyor (17), and a frame-shaped traveling frame (24) is disposed on the hollow roller conveyor (23). A compression mold (26) equipped with a flange (25) is removably suspended on the outer periphery of the upper end of the traveling frame (24) via the flange (25). , the lower surface of the compression mold (26) has a recess (27) corresponding to the shape of the upper half of the desired core.
It has an outer shape that can be fitted into the recess (6) of the lower mold (7).

A recess (28) is formed on the upper surface of the compression mold (26), and an extrusion plate (30) with a plurality of extrusion bottles (29) implanted in the underside of the recess (28) is disposed within the recess (28). The extrusion bottle (29) is connected to the compression mold (26).
) and is provided so as to be able to appear and retract from the bottom surface of the recess (27).

Moreover, a coil spring (
31> is ring-ringed, and the extension force of the coil spring (31) acts to push the push-out plate (30) upward.

Furthermore, the extrusion plate (3) is located at the upper position of the recess (28).
A stopper (33) is provided to limit the rise of the ejector pin (30), and the ejector pin (30) is in contact with the ejector plate (30).
The position is adjusted so that the lower end of the mold (29) is at the same level as the lower surface of the compression mold (26). Furthermore, the traveling frame (
24) includes a piston rod (35) of a horizontal cylinder (34) provided at the end of the roller conveyor (23).
) are connected, and the compression mold (26) is reciprocated on the roller conveyor (23) together with the traveling frame (24).

Further, a downward cylinder (36) is disposed above the roller conveyor (23) opposite to the upward cylinder (21), and the lower end of its piston rod (37) corresponds to the extrusion plate (30). A push-down plate (38) is fixed thereto.

With this structure, the upward cylinder (1) is extended in the state shown in Fig. 1, and the lower mold (7) is placed on the table (
3), and the blowing mold (12) is relatively fitted into the recess (6) of the lower mold (7), and the upper surface of the lower mold comes into contact with the stopper (16) and stops rising. do. As a result, the recess (6) of the lower mold (7) and the recess (11) of the blowing mold (12) define a preforming cavity whose upper half is enlarged upwards compared to the desired shape of the core. Ru.

Next, compressed air is supplied into the blow tank (10), and the raw sand contained therein is blown into it via i (13>).
The preformed cavity is blown and filled to leave the preformed body. At this time, the compressed air blown in with the green sand is discharged into the atmosphere from the vent plug (15) through the exhaust port (14).

Next, the upward cylinder (1) is retracted, and the lower mold (7) is lowered with the preform held in the recess (6) of the lower mold (7) to form the blowing mold (12). Perform the separation.

Next, the horizontal cylinder (34) is operated to extend and the compression type (
26) together with the traveling frame (24) to a position between the lower mold (6) and the blowing mold (12), the upward cylinder (1) is again extended and the lower mold (7) is raised. .

Due to this operation, the upper surface of the preform held on the lower mold (7) comes into contact with the lower surface of the compression mold (26), and the lower mold (
7) continues to rise, the compression mold (26) is separated from the traveling frame (24) and lifted, and the rise continues until the upper surface of the compression mold (26) becomes the lower surface of the blowing mold (12). When the compression mold (26) comes into contact with the lower mold (7) and stops rising, only the lower mold (7) continues to rise, the compression mold (26) is relatively fitted into the recess (6) of the lower mold (7), and the preform is As the preform is compressed, the upper surface of the lower mold (7) comes into contact with the stepped portion of the lower surface of the compression mold (26), and its rise is stopped, compressing the preform into the desired shape of the core.

Next, while the extrusion cylinder (4) is extended, the upward cylinder (+) is retracted. Created by this operation! The core is pressed upward by the extrusion bottle (8) and the lower mold (7) is lowered, so that it is compressed into the compression mold (26).
After being separated from the lower mold (7) while being held in the core, the compression mold (26) holding the core begins to descend together with the lower mold (7) while being supported by the extrusion bottle (8), and the compression mold ( 2
The flange (25) of 6) comes into contact with the traveling frame (24), its descent is stopped, and separation from the lower mold (7) is performed.

Next, the horizontal cylinder (34) is retracted and the compression type (2
6) Together with the e-traveling frame (24), the roller conveyor (
17) The upper frame (19) is moved to a position directly above the green sand mold (20), and the upward cylinder (2I) is extended and the green sand is moved through the push-up plate (22) and surface plate (18). Main type (2
0) is pushed up, the core held in the compression mold (26) is relatively fitted into the core setting position of the green sand main mold (20), and its ascent is stopped.

Next, the downward cylinder (36) is operated to extend, and the push-down plate (36) is operated to extend.
8> and the extrusion plate (30), the upward cylinder (21) is retracted while the extrusion bottle (29) is not pressed down against the coil spring (31), and the core is compressed. (26) and held on the green sand main mold (20) side, the green sand main mold (20) is lowered together with the surface plate (18) and returned to the top of the roller conveyor (17), and then The green sand main mold (20) is moved one pitch by the mold feeding device, and the next green sand main mold (20) is moved to the push-up plate (22).
Position it directly above.

Meanwhile, at the lower mold (7) position, a preform is molded using the blowing mold (12) in the same manner as described above.

By repeating the above operations, the molding of the green sand core and the setting of the core into the green sand main mold (20) are performed in sequence.

In the above embodiment, the core held in the compression mold (26) is set in the green sand main mold (20) by raising the green sand main mold (20). As shown in Fig. 2, the roller conveyor (23) is divided to form a divided roller conveyor (23').
3') can be raised and lowered by a cylinder (40) via a frame (39), and a traveling frame (24)
By connecting the horizontal cylinder (34) with the vertically slidable rod (41), the green sand main mold (
It is possible to set the core by lowering the compression mold (26) together with the divided roller conveyor (23') without raising the mold (20).

<Effects of the Invention> As described above, the present invention produces a preformed body whose upper half is enlarged upwardly compared to the shape of a desired core, and compresses and molds this preformed body into the shape of the desired core. By doing so, it is possible to mold a core in which the strength of the central thick part and the peripheral thin part are almost uniform.

Furthermore, the green sand in the central thick-walled part of the preform is well compacted by the compression mold, so the transferability of this part is improved, and a core with better dimensional accuracy can be obtained. Furthermore, by using a device that is associated with a roller conveyor for transporting green sand molds, various effects can be obtained, such as allowing the molded core to be released from the compression mold and set in the main mold at the same time.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing an embodiment of the present invention, and Fig. 2 is a longitudinal sectional front view showing an embodiment of the present invention.
FIG.

Claims (3)

[Claims] (1) A lower mold with a recess formed on the upper surface corresponding to the shape of the lower half of the desired core, and a blowing mold with a recess formed on the lower surface with a vertical dimension larger than the shape of the desired upper half of the core. A step of aligning the molds with their concave portions facing each other to define a preformed cavity, and blowing and filling green sand together with compressed air into the preformed cavity to form a preformed body. separating the blowing mold from the lower mold while holding the preform in the recess of the lower mold; and forming a recess corresponding to the shape of the upper half of the desired core on the lower surface. a step of carrying a compression mold above the lower mold and aligning the compression mold and the lower mold with their recesses facing each other, thereby compression-molding the preform into the shape of a desired core; separating the lower mold from the compression mold while holding the compression-molded core in the recess of the compression mold; and carrying out the core held in the compression mold together with the compression mold from above the lower mold; A method for shaping a green sand core, comprising the step of separating the core from the recess of the compression mold. (2) A recess (6
) is disposed so as to be movable up and down, and a blow tank (10) is disposed above the lower die (7) at an appropriate interval. A recess (11) whose vertical dimension is larger than the desired shape of the upper half of the core is formed on the lower surface of the lower end, and the lower mold (7)
) A blow mold (12) having an external shape that can be slidably fitted is fixed to the recess (6) of the blow tank (10), and the sand is blown into the blow mold (12) and the bottom plate of the blow tank (10) by penetrating the blow mold (12) and the bottom plate of the blow tank (10). A hole (13) is bored, and a hollow roller conveyor is disposed outward from a position between the lower die (7) and the blowing die (12), and a hollow roller conveyor is provided on the lower surface. A recess (27) corresponding to the desired shape of the upper half of the core is formed, and the lower mold (7)
A compression mold (26) having an external shape that can be fitted into the recess is movably mounted via a traveling frame (24), and a molding core extrusion mechanism (29) (30) is mounted on the compression mold (26). )(3
1) A green sand core molding device characterized in that (33) is attached. (3) A recess (6
) is disposed so as to be movable up and down, and a blow tank (10) is disposed at an appropriate interval above the lower die (7), and the lower end of the blow tank (10) is disposed above the lower die (7). In the department,
A recess (11) whose vertical dimensions are larger than the shape of the desired upper half of the core is formed on the lower surface, and a recess (11) is formed on the lower surface of the core.
) A blowing mold (12) having an external shape that can be slidably fitted is fixed to the recess (6) of the blowing mold (12), and the sand is blown by passing through the blowing mold (12) and the bottom plate of the blow tank (10). A hole (13) is bored, and a roller conveyor (17) for transporting the green sand main mold is installed outside the lower mold (7), and the lower mold (7) and the blowing mold (12) are connected to each other. A hollow roller conveyor is arranged from a position in between to a position above the roller conveyor (17) for transferring the green sand main mold, and above the hollow roller conveyor, the bottom surface corresponds to the shape of the upper half of the desired core. A compression mold (26) having a recess (27) formed therein and having an outer shape that can be fitted into the recess of the lower mold (7) is mounted so as to be movable via a traveling frame (24). 26) A green sand core molding device characterized in that a molding core extrusion mechanism (29), (30), (31), and (33) is attached.