JPH0536146B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mold apparatus for so-called stack mold production in which a large number of frameless green sand molds are stacked vertically.

(Prior technology) Conventionally, green sand molds with cavity surfaces formed on both the upper and lower sides were stacked one above the other to form a stack mold. Green sand was blow-filled into the cavity defined by the mold and two pattern plates. Then, the green sand is compressed using the two pattern plates to form a mold, and the molds are extracted from the flask and stacked.

(Problems to be Solved by the Invention) However, in the green sand mold formed as described above, since the pattern plate defining the blowing cavity and the pattern plate used for compression are the same pattern plate, 1. The hardness and strength of the thick and thin parts of the mold are different.

2. If the thick wall part of the mold is made to have a predetermined hardness and strength, the hardness and strength of the thin wall part will become higher than necessary.

3. If the thickness of the mold is not made considerably thick, the compression allowance will be small and the hardness and strength of the thick walled part will be insufficient due to compression.

Due to these factors, during casting, the amount of fluctuation (distortion) due to the hot water pressure differs in each part of the mold, making it difficult to obtain a cast with good precision.Also, in areas where the density has increased more than necessary, casting defects due to gas etc. There is a problem that appears.

Furthermore, since the thickness of the mold had to be made thicker than necessary, a large amount of kneaded sand was required.

(Object of the Invention) The present invention has been made in view of the above circumstances, and aims to provide a mold device suitable for obtaining a green sand stack mold having uniform strength. be.

(Structure) Below, the structure of the present invention will be explained in detail based on illustrated examples. Reference numeral 1 denotes an upward cylinder mounted upward on a fixed frame. At the tip of the piston rod, there is a table with a recess 2 formed on the upper surface. 3 is fixed.

A lower mold 5 having a recess 4 formed on the upper surface is fixed to the upper part of the table 3, and a product corresponding to the lower surface shape of the desired mold M (the upper surface shape of the casting cavity) is attached to the bottom surface of the recess 4. A model section 6 and a runner model section 7 are attached.

Further, at the end of the runner model part 7, a sprue rod model 9 connected to a piston rod of a cylinder 8 provided upward in the recess 2 of the table 3 is provided so as to be movable up and down through the lower mold 5. It is being

Further, within the recess 2 of the table 3 is an extrusion plate 10 that is raised and lowered by a cylinder (not shown).
is provided, and an extrusion pin 11 is attached to the extrusion plate 10, which penetrates the lower die 5 and projects into and out of the recess 4.

The recess 4 is adapted to define a cavity corresponding to a preforming cavity or a desired mold M by fitting a blow mold or a compression mold to be described later.

A blow tank 12 is disposed above the table 3 at an appropriate interval, and a recess whose vertical dimension is larger than the shape of the upper surface of the desired mold M is provided on the lower surface of the blow tank 12. A blowing mold 15 having a guide hole 14 formed therein and having a guide hole 14 into which the sprue rod model 9 can be inserted is fixed to the lower mold 5 with an external shape that can be fitted into the recess 4 of the lower mold 5.

In addition, the bottom plate of the blow tank 12 and the blow mold 15
A blow hole 16 is bored through the guide hole 14, and a compressed air supply hole 17 into which a vent plug is fitted is communicated with the guide hole 14.

A sprue model 9a having a through hole 14a into which the sprue rod model 9 can be inserted is fixed to the lower end of the guide hole 14 with the through hole 14a communicating with the guide hole 14.

A stopper 18 is fixed to the outer periphery of the lower surface of the blow tank 12 so as to surround the blowing mold 15, and the lower surface of the stopper 18 can come into contact with the outer periphery of the upper surface of the lower mold 5.

Further, a hollow roller conveyor 19 is disposed outward from a position between the lower die 5 and the blowing die 15, and a frame-shaped traveling frame 20 is not shown on the hollow roller conveyor 19. It is mounted so that it can run using a cylinder.

A compression mold 22 having a flange 21 on the outer periphery of the upper end is removably suspended from the traveling frame 20 via the flange 21.
A recess 23 is formed on the lower surface of 2, and the recess 23 is larger in vertical dimension than the shape of the desired mold M on the upper surface.

In addition, a plug model 23a slides into the recess 23, which is lowered by the operation of the cylinder 24 to close the lower end of the recess 23, and is raised to form a recess corresponding to the shape of the upper surface of the desired mold M. They are arranged so that they can move freely.

Further, a guide hole 25 into which the sprue rod model 9 can be inserted is bored in the lower surface of the compression mold 22.
The guide hole 25 communicates with a compressed air supply hole 26 into which a vent plug is fitted. Further, at the lower end of the guide hole 25, a sprue model 9b having a through hole 25a into which the sprue rod model 9 can be inserted is provided with the through hole 25a communicating with the guide hole 25, and the compression mold 22 is connected to the sprue model 9b. A recess 27 into which the sprue model 9a of the blow mold 15 can be inserted is bored in the upper surface corresponding to the sprue model 9b.

Further, a stopper 28 is fixed to the lower surface of the flange 21 of the compression mold 22 so as to surround the compression mold 22 and can come into contact with the outer periphery of the upper surface of the table 3.

(Function) The device configured in this way is shown in Fig. 3.
When molding the lowest mold, the cylinder 8 is retracted to bring the tip of the sprue rod model 9 to the same level as the bottom of the recess 4. When molding other molds, the cylinder 8 is extended. After the sprue rod model 9 is in a state of protruding to the position shown by the broken line in FIG. The upper surface of the holder contacts the stopper 18 and its upward movement is stopped. As a result, the concave portion 4 of the lower die 5 and the blowing die 15 define a preformed cavity whose upper surface shape is enlarged upwardly than the shape of the desired mold M. Further, when the sprue rod model 9 is extended, the sprue rod model 9 is fitted into the through hole 14a of the sprue model 9a and the guide hole 14.

In this state, compressed air is supplied into the blow tank 12, and the raw sand stored inside is injected into the blow hole 1.
6, the preform cavity is blown and filled to form a preform.

Next, the upward cylinder 1 is retracted and the lower mold 5 is lowered with the preform held in the recess 4 of the lower mold 5 to separate it from the blowing mold 15.

At this time, compressed air is supplied from the compressed air supply hole 17 to the guide hole 14 to remove molding sand accumulated in the guide hole 14. Next, a cylinder (not shown) is operated to move the compression mold 22 together with the traveling frame 20 to a position between the lower mold 5 and the blowing mold 15, and then the upward cylinder 1 is operated to extend again to raise the lower mold 5. . At this time, when molding the uppermost mold in FIG. 3, the cylinder 24 is extended and the plug model 23a is lowered to close the recess 23.

Due to the above operation, the upper surface of the preform held by the lower mold 5 comes into contact with the lower surface of the compression mold 22, and the lower mold 5 continues to rise, and the compression mold 22 is separated from the traveling frame 20 and lifted up. , the upper surface of the compression mold 22 becomes the blowing mold 15.
When it comes into contact with the lower surface and stops rising, only the lower mold 5 continues to rise, so that the compression mold 22 fits relatively into the recess 4 of the lower mold 5 and compresses the preform. The upper surface comes into contact with the stopper 28 of the compression mold 22, and its upward movement is also stopped, compressing the preform into the shape of the desired mold M. As a result, the thick and thin parts of the mold are compressed at approximately the same compression rate.

Next, the upward cylinder 1 is retracted to lower the lower mold 5 with the desired mold M held in the recess 4 of the lower mold 5 and separated from the compression mold 22. Thereafter, the compression mold 22 is returned to the position shown in FIG.
5. Remove the molding sand that has accumulated in the chamber.

Next, the cylinder 8 is retracted and the sprue rod model 9 is lowered to the state shown by the solid line in FIG. The lower mold 5 is released from the recess 4 and the desired mold M is taken out.

The desired molds M are sequentially molded in this manner and stacked by hand or machine to complete a stack mold as shown in FIG.

(Effects of the Invention) As described above, the present invention first molds a preform whose dimensions are larger than the shape of the upper surface of the desired mold, and compresses this preform into the shape of the desired mold. Since the mold is constructed to be able to produce molds, the strength of the thick and thin parts of the mold is almost uniform, making it possible to produce green sand molds, which solves all the drawbacks of green sand molds made using the conventional blow squeeze method. It has excellent effects.

Furthermore, in addition to the above-mentioned mold configuration, a sprue can be formed as necessary, and at the same time, a plug model can be arranged to be able to be raised and lowered, and the upper surface of the mold can be flattened as necessary to create a mold that can be stacked one on top of the other. Since it has a mold structure that allows for the formation of stack molds, it has the excellent advantage that all the various molds required for stack molds can be made, and its effects are significant.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view showing a state in the middle of operation, and FIG.
A cross-sectional view showing the operating state of the lower mold and the forming mold, and FIG. 3 is a cross-sectional view of the completed stack mold. 4: recess, 5: lower mold, 6: product model, 7: runner model, 9: sprue rod model, 9a, 9b: sprue model, 12: blow tank, 13: enlarged recess, 1
5: Blow mold, 22: Compression mold, 23: Recessed part, 23
a: Plug model.

Claims (1)

[Claims] 1 A recess 4 corresponding to the external dimensions of the desired mold M is formed, and a product model part 6 and a runner model part 7 corresponding to the shape of the lower surface of the desired mold M are provided on the bottom surface of the recess 4, and the runner a lower mold 5 which can be lowered and lowered and which is provided with a sprue rod model 9 that is in sliding contact with the model part 7 so as to be able to protrude upward from the bottom surface of the recess 4; a blow tank disposed above the lower mold 5; 12, a sprue model 9a having a concave portion 13 enlarged upwardly than the upper surface shape of the desired mold M on the lower surface, and a through hole 14a is attached at a position corresponding to the sprue rod model 9; The blowing mold 15 has an outer shape that can be fitted into the recess 4; the plug model 23a is fitted so as to be able to move up and down; the recess 23 has a shape corresponding to the shape of the upper surface of the desired mold M; and the sprue rod model Through hole 25 at the position corresponding to 9
A mold device for producing a stack mold, comprising: a compression mold 22 having a sprue model 9b attached thereto and having an external shape that can be fitted into the recess 4;