JPH0534105B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a green sand core molding device, and more specifically, to a green sand core molding device in which the thick part and thin wall part have greatly different dimensions. related to a device for

(Conventional technology) Cores are manufactured using shell molding, cold boxing, CO ₂ molding, etc. mainly for reasons of strength and dimensional accuracy.
Generally, cores made by this method are expensive and have different properties from the main mold made of green sand, so they require sand recycling treatment after pouring. There is a problem above. For this reason, various methods of molding cores using the same raw sand as the main mold have recently been attempted, and cores of relatively simple shapes that can be used for practical purposes are being molded. .

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 it is an object of the present invention to provide an apparatus for molding green sand cores having a complex shape and having uniform strength and good dimensional accuracy. It is something.

(Structure of the Invention) The structure of the present invention will be explained in detail below with reference to the illustrated example. Reference numeral 1 denotes an upward cylinder mounted upward on a frame 2, and a table 4 having a recess 3 formed on the upper surface is fixed to the tip of the piston rod. There is.
An upwardly directed extrusion cylinder 5 is erected in the recess 3 of the table 4, and a connecting plate 6 is fixed to the tip of the piston rod of the extrusion cylinder 5.

A lower mold 9 is mounted on the table 4, which has a recess 7 formed in its upper surface having a shape corresponding to the shape of the lower half of the desired core, and a recess 8 opposite to the recess 3 formed in its lower surface. . Moreover, in the recess 8,
An extrusion plate 11 having a plurality of extrusion pins 10 implanted on its upper surface is connected to the connecting plate 6, and the extrusion pins 10 penetrate the lower mold 9 and protrude and retract from the bottom surface of the recess 7. It is possible to do so.

A frame-shaped mold 14 is integrally fixed to the upper part of the lower mold 9 and has an air inlet 12 on the side wall and a hollow part 13 communicating with the recess 7 of the lower mold 9.

Furthermore, a horizontally long fixed frame 15 is installed above the mold 14, and a fixed frame 15 is provided on the lower surface of the fixed frame 15. A mold 16 is fixed. On the outer periphery of the fixed upper mold 16, there is a rectangular slide mold 18, which has through holes 17, 17 bored in the upper side thereof, which pass through the left and right sides. The curved slide mold 1 is fitted in a state where it is possible to
The lower end of the fixed upper mold 16 is projected downward from the lower surface of the upper fixed mold 16 .

Incidentally, the rectangular slide mold 18 is positioned and disposed so as to define a shape corresponding to the desired upper half shape of the core with the fixed upper mold 16 in the raised state, and the hollow portion 13 It has an external shape that can be fitted inside. On the other hand, the upper end of the curved slide mold 18 is connected to the tip of a piston rod of a downward cylinder 20 provided downward on the fixed frame 15 via a portal frame 19. The curved slide mold 18 is prevented from rising. Further, a stopper member 21 is disposed on the lower surface of the fixed frame 15 at an outside position of the square-shaped slide mold 18 so as to surround the square-shaped slide mold 18, and the lower end of the stopper member 21 is connected to the fixed upper mold. The lower surface of 16,
It is located midway between the through hole of the square-shaped slide mold 18.

Further, a J-shaped blow tank 22 is fixed to the fixed frame 15, and a blow plate 23 of the blow tank 22 is attached to the stopper member 22.
The upper part is connected and fixed to the outside of 1 in a vertical state.

The blow plate 23 is provided with the frame-shaped mold 1.
A blow hole 24 communicating with the blow port 12 is provided in a state where the blow hole 4 is raised and partially fitted into the lower end of the curved slide mold 18.

Further, a slide gate 26 operated by a cylinder 25 is provided at the upper end of the blow tank 22, and is adapted to supply one batch of green sand 27 into the blow tank 22.

In the figure, 28 is an exhaust hole, and 29 is a vent plug.

(Operation of the invention) The device configured in this way has a downward cylinder 2.
0 is activated to push down the slide die 18, the upward cylinder 1 is extended and the lower die 9 and the filling die 14 are raised via the table 4,
The lower end of the slide mold 18 is fitted into the hollow part 13 of the filling mold 14, and the rising is temporarily stopped at the position where the blow port 12 matches the blow hole 24 of the blow plate 23 (as shown by the chain line in FIG. 1). . As a result, the lower die 9, the filling die 14, the slide die 18, and the fixed upper die 16 form a preformed cavity (with dimensions in which the shape of the upper half is enlarged in the vertical direction than the desired core (the chain diagram in FIG. 2). (solid line diagram in FIG. 2) is defined. Moreover, this enlarged dimension differs between the thick walled part and the thin walled part, and the enlarged dimension b' in the thick walled part is larger than the enlarged dimension a' in the thin walled part, and the ratio of the two dimensions is the same as that of the thick walled part b in the desired core. The dimensional ratio is approximately equal to that of the thin wall portion a.

In this state, compressed air is supplied into the blow tank 22, and the green sand 27 contained therein is blown and filled into the preform cavity through the blow hole 24 and the blow port 12 to form a preform. do. The compressed air blown in together with the green sand 27 at this time is discharged into the atmosphere through the vent plug 29 and the exhaust hole 28.

Next, after the downward cylinder 20 is brought into a free state, the upward cylinder 1 is further extended and the filling mold 1 is moved.
The lower mold 9 and the mold 14 are raised until the mold 4 contacts the stopper member 21, and the preform is compressed to form a green sand core.

To explain in more detail the compression of the preform at this time, as the lower mold 9 and the mold 14 are raised, the slide 18 is also raised by a certain distance.
For this reason, the thin-walled portion of the preform is not compressed, but the thick-walled portion of the fixed upper die 16 is compressed first. Then, the lower surfaces of the through holes 17 and 17 of the slide mold 18 come into contact with the fixed frame 15, and the slide mold 18
is stopped, and the lower mold 9 and the filling mold 14 continue to rise, thereby further compressing both the thin-walled portion and the thick-walled portion, and when the molding mold 14 comes into contact with the stopper member 21, the reserve is removed. The molded body is compression molded into the shape of a desired core, and its ascent is stopped.
In other words, the green sand core is molded with the compression ratios of the thick and thin parts being approximately equal.

Next, while the downward cylinder 20 is extended, the upward cylinder 1 is retracted. The green sand core shaped by this operation is pushed downward by the slide mold 18 and held on the lower mold 9 and filling mold 14 side, and is first separated from the fixed upper mold 16, and then slides. The lower mold 9 is separated from the mold 18.
Then, it is lowered together with the filling mold 14 to the lowering end.

Next, the extrusion cylinder 5 is operated to extend, and the connecting slope 6
Then, the extrusion pin 10 is raised via the extrusion plate 11, the green sand cores held in the lower die 9 and the filling die 14 are removed and separated, and the green sand cores are taken out by an appropriate method, and then extruded. The cylinder 5 is retracted and the push-out pin 10 is returned down.

During this time, green sand 27 for blowing is introduced into the blow tank 22 by operating the slide gate 26 by operating the cylinder 25.

The above operation is regarded as one cycle, and the same cycle is repeated thereafter.

In the above embodiment, the mold 14 is attached to the upper part of the lower mold 9, but the same effect can be obtained even if the mold 14 is integrated with the mold 14.

Further, in the embodiment, the raising of the lower die 9 and the filling die 14 when defining the preforming cavity is stopped by temporarily stopping the operation of the upward cylinder 1. Alternatively, another stopper member may be moved in and out to perform positioning.

Furthermore, the green sand core in the example has a thick part in the center, and the fixed upper mold 1 is arranged accordingly.
6 is placed in the center, and a shaped slide mold 18 is arranged to surround it. However, if the thick and thin parts of the core are separated into left and right sides, the fixed upper mold 16 and the slide mold 18 The molds 18 may be arranged side by side, and in this case, the slide molds do not need to be shaped.

(Effects of the Invention) The present invention has a fixed upper mold and a sliding mold that can be raised and lowered in correspondence with the lower mold and the filling mold that can be raised and lowered as described above, so that the upper half shape is smaller than the desired shape of the core. A preform cavity with enlarged dimensions in the vertical direction is defined, green sand is blown and filled into the preform cavity to form a preform, the thick part of this preform is first compressed, and then the preform is further preformed. The device is configured to be able to mold green sand cores by compressing both the thick and thin parts of the body into the desired core shape, so even cores with complex shapes can have almost uniform strength. Not only can it be molded into a core, but it can also be molded into a green sand core with good dimensional accuracy.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the present invention, and FIG. 2 is a dimensional comparison diagram showing the relationship between a preformed cavity and a desired core. 7: Recess, 9: Lower mold, 12: Inlet, 13:
Hollow part, 14: Embankment mold, 16: Fixed upper mold, 18: Slide mold, 22: Blow tank, 24: Blow hole.

Claims (1)

[Claims] 1. A lower mold 9 having a recess 7 corresponding to the shape of the lower half of the desired core is arranged so as to be movable up and down and stopped midway;
A frame-shaped mold 14 is attached to the upper part of the lower mold 9, and has a blowing port 12 on the side and a hollow part 13 penetrating vertically. A fixed upper mold 16 having a surface corresponding to the shape of the upper part is fixedly disposed at intervals, and can be slid up and down by a predetermined distance on the side of the fixed upper mold 16, and can be fitted into the hollow part 13. A slide mold 18 having an external shape is disposed with its lower end protruding downward from the lower surface of the fixed upper mold 16, and the slide mold 18
A green sand core molding apparatus characterized in that a blow tank 22 having a blow hole 24 that can communicate with the blow port 12 is disposed outside the blow tank 22.