JPH05115943A - Vibrator for lost foam pattern casting - Google Patents

Abstract

PURPOSE:To improve the filling efficiency of molding sand in a lost foam pattern casting and to sufficiently secure the filling density of the molding sand around the lost foam pattern even in the case the lost foam pattern has complicated shape such as one having a hole facing sideward or a surface facing downward. CONSTITUTION:A table 3 is arranged as horizontally and freely rockably on a machine base 1 through plural air springs 2, 2 and one set of a piston reciprocating vibration exciter 4 vertically reciprocating by using compressed air supplied from an air compressor 10 as the driving source is fitted at the center part of the lower surface of this table 3. Further, vibrating motors 12 mutually faced in the horizontal direction are fixed and plural clamps 11, 11 having a cylinder device, such as hydraulic cylinder, air pressure cylinder, or mechanical opening/closing type structure for fixing a flask 5 are arranged on the table 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vanishing model casting method for molding and casting a mold by using a model which burns and melts when heated and vanishes, and a molding sand is placed in a flask in which the vanishing model is installed. The present invention relates to a vibrating device for disappearing model casting, which is densely and uniformly filled.

[0002]

2. Description of the Related Art Conventionally, in the vanishing model casting method, generally, a vibrating device shown in FIG. 6 is often used for the work of filling foundry sand in a casting frame in which a vanishing model made of a foam molding is installed. There is. This vibrating device includes a table 3 horizontally and swingably arranged on a machine base 1 via springs 2 and 2, and two vibration motors attached to the lower surface of the table 3 to vibrate the table 3. The vibrators 4 and 4 are provided. Therefore, by rotating the both exciters 4 and 4 in directions opposite to each other, the resultant force produces an exciting force in the normal and reverse directions. The table 3 and the casting frame 5 placed on the upper surface of the table 3 vibrate with a predetermined amplitude of acceleration in the vertical and reverse directions due to the exciting force in the normal and reverse directions. This vibration is also transmitted to the molding sand 6 filled in the casting frame 5 to move and displace the molding sand 6. As a result, the space in the casting frame 5 in which the vanishing model 7 is installed is filled with the foundry sand 6.

Furthermore, Japanese Patent Laid-Open Publication No. 62-199245.
In the No., the vibration motor is fixed in parallel to the lower surface of the vibration table which is swingably arranged on the machine base via the air spring, and the vibration motor is fixed to the peripheral side surfaces of the vibration table in opposition to each other. A vibration table is disclosed which can simultaneously vibrate the vibration table in the vertical and horizontal directions. Therefore, even if the model has a complicated shape having a hole deeply drilled in the lateral direction and a downward surface, 4 to 6 vibrations are applied to the lower surface of the vibrating table and the peripheral side surface of the vibrating table to uniformly fill the molding sand. A motor is fixed so that the vibration table can be vibrated in the vertical direction and the front-rear direction, or in the horizontal direction of the front-rear direction and the left-right direction. To 3G to fluidize the foundry sand in the flask and 0.8 to 1G in the horizontal direction, and then 1V or less with a vertical time difference. Even if the model has a complicated shape, the molding sand can be uniformly filled.

However, these conventional vibration devices have a drawback that the casting sand 6 cannot be filled in the casting frame 5 uniformly in a short time with high density and the filling efficiency is poor. As a result of earnest research by the present inventor, it was confirmed that the reason is as follows. That is, in the amplitude measurement diagram (FIG. 7), the amplitude characteristics of the table 3 are indicated by 7-1, and the amplitude characteristics of the surface of the vanishing model 7 inside the casting frame 5 are indicated by 7-2, so that both are relatively smooth. However, since it is practically difficult to completely synchronize the two exciters 4 and 4 with each other, the characteristic curve 8 is shown in the acceleration measurement diagram (FIG. 8).
The acceleration of the table 3 shown by -1 and the acceleration of the surface of the vanishing model 7 in the casting frame 5 shown by the characteristic 8-2 show irregular acceleration characteristics that do not correspond to the amplitude characteristics of FIG. 7, respectively. Then, the vibration transmissibility to the foundry sand 6 becomes insufficient, which hinders smooth movement displacement of the foundry sand 6.

On the other hand, the length W of one side shown in FIG.
A molding frame 8 made of transparent acrylic resin having a height of 0 mm and a height H of 400 mm is provided, and a half-divided cylindrical foam having a radius R of 18 mm and an axial length L of 100 mm is provided on the inner surface at a position where the depth D is 300 mm. A test piece 9 made of a molded product is attached in a horizontal posture, and in a state where the space inside the casting frame 8 is filled with the molding sand 6, the test piece 9 is placed and fixed on the table 3 of the conventional vibration device and vibrated. Thus, a filling experiment of the molding sand 6 into the space 9A of the test piece 9 was performed. As a result, it was confirmed that, within 120 seconds, the molding sand 6 was not filled in the space 8A even if the acceleration was set to 2G and vibration was applied. This indicates that if the vanishing model 7 has a complicated shape with lateral holes and downward faces, it is not possible to secure a sufficient packing density of the molding sand 6 around the vanishing model 7. ..

Further, the same filling experiment of foundry sand was conducted under the same conditions as in FIG. 10 using a three-dimensional vibration table using a vibration motor. As a result, when the radius R of the space portion 9A of the test piece 9 is 18 mm, if acceleration in the horizontal direction (XY) is added to acceleration in the vertical direction as shown in FIG. 9,
It was confirmed that the molding sand 6 was filled in the space 9A, but when the radius R of the space was 4 mm, the molding sand 6 was filled in the space 9A even when vibration was applied in three vertical and horizontal directions. I confirmed that it will not be done.

[0007]

The problem to be solved is that the conventional vibrating device cannot fill the molding sand with high density and evenly in a short time in the molding frame, resulting in poor filling efficiency. When the vanishing model has a complicated shape with lateral holes and downward faces, it is impossible to secure a sufficient packing density of the foundry sand around the vanishing model.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a table which is swingably arranged on a machine base via a spring, and a compressed air which is attached to the table and vertically vibrates the table as a drive source. In order to vibrate the table in a horizontal direction, the vibration motors are fixed to the side surfaces of the piston reciprocating vibration exciter, and the casting frame placed on the table is detachable. It is equipped with a clamp for fixing to the cast iron, which improves the filling efficiency of the foundry sand, and even if the vanishing model has a complicated shape with sideways holes and downward faces, the casting around the vanishing model is The purpose of ensuring a sufficient packing density of sand was achieved.

[0009]

According to the present invention, by operating a single piston reciprocating vibrator using compressed air as a drive source, vertical and reverse vibrational forces are generated. By this exciting force, a table horizontally and swingably arranged via a spring and a casting frame placed on the upper surface of the table and fixed by a clamp are accelerated at a predetermined amplitude in the vertical and reverse directions. To vibrate. Furthermore, the vibration force of the vibration motor fixed to the side surface facilitates horizontal movement of the molding sand fluidized by vertical vibration, and these vibrations are transmitted to the molding sand in the molding frame and move the molding sand. It is to displace.

By operating one piston reciprocating type vibration exciter, vertical and reverse directions of excitation force are generated, so that the acceleration characteristics of the table and the disappearing model surface correspond to the amplitude characteristics of the table and the disappearing model surface. As a result, the sand is easily moved by the horizontal vibration force of the vibration motor. As a result, the vibration is sufficiently transmitted to the foundry sand, the displacement thereof is improved, and the filling efficiency of the foundry sand is improved. Further, even if the vanishing model has a complicated shape with lateral holes and downward faces, it is possible to sufficiently secure the filling density of the foundry sand around the vanishing model.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a front view and a plan view showing an example of a vibrating device for vanishing model casting according to the present invention. It should be noted that the same or corresponding parts as those of the conventional example will be described with the same reference numerals. In this figure, a table 3 is horizontally and swingably disposed on a machine base 1 via a plurality of air springs 2 and 2. One vibrator 4 is attached to the center of the lower surface of the table 3. This vibrator 4 has a piston (not shown) incorporated therein, which uses a compressed air supplied from an air compressor 10 as a drive source to reciprocate in the vertical direction. Is composed of a vibration exciter to which two pairs of opposing electrically driven vibration motors 12 and 12 are attached and which is vibrated in the horizontal direction by the resultant force of rotation of unbalanced weights (not shown). Further, the table 3 is provided with a plurality of clamps 1 having a cylinder device such as a hydraulic cylinder or a pneumatic cylinder or a mechanical opening / closing structure.
1, 11 are provided. The lower end of the casting frame 5 placed on the upper surface of the table 3 is firmly fixed to the table 3 by the clamps 11, 11. The casting sand 5 contains casting sand 6
Is filled with water and disappears inside the molding sand 6
Is installed.

According to the above construction, the air compressor 1
Driving one piston reciprocating vibrator 4 using compressed air supplied from 0 as a drive source generates vertical and reverse vibrational forces, and further vibrates electrically driven in horizontal direction. A horizontal excitation force is generated by operating the motor. By this exciting force, the table 3 horizontally and swingably arranged via the air springs 2 and 2, and the casting frame 5 placed on the upper surface of the table 3 and firmly fixed by the clamps 11 and 11. 1 with a predetermined amplitude in the vertical and reverse directions
Vibrate with an acceleration of G to 3G, preferably 2G,
At the same time, it is vibrated in the horizontal direction with an acceleration of about 0.8G. This vibration is transmitted to the molding sand 6 in the casting frame 5 and the molding sand 6
Move and mutate.

According to the present invention, one piston reciprocating type vibrator 4 is operated to generate the vibration force in the vertical and reverse directions. Therefore, the amplitude characteristics of the surface of the table 3 and the vanishing model 7 are: In FIG. 3, the amplitude characteristic of Table 3 is 3-1.
As shown by 3-2, the amplitude characteristics of the surface of the vanishing model 7 in the casting frame 5 show a smooth sine curve, and the acceleration characteristics are shown in Table 3 shown in FIG. And the acceleration of the surface of the vanishing model 7 in the casting frame 5 shown by 4-2 become regular corresponding to the amplitude characteristics of FIG. 3, respectively. Further, by vibrating in the horizontal direction, the molding sand 6 can be easily moved in the horizontal direction. As a result, vibration is sufficiently transmitted to the foundry sand 6, the movement displacement thereof is improved, and the filling efficiency of the foundry sand 6 is improved. or,
Even if the vanishing model 7 has a complicated shape with lateral holes and downward faces, a sufficient packing density of the molding sand 6 around the vanishing model 7 can be ensured.

A half-split cylindrical foam having a radius R of 18 mm and an axial length L of 100 mm is formed on the inner surface at a depth D of 300 mm in the same transparent acrylic resin molding frame 8 shown in FIG. Molded test piece 9
Is attached in a horizontal posture, and the space inside the casting frame 7 is filled with the foundry sand 6 and placed on the table 3 of the vibration device of the present invention described in the above embodiment, and then the clamp 11, By firmly fixing with 11 and vibrating, the test piece 9
The relationship between the filling time of the molding sand 6 and the acceleration in the space 9A was determined by experiments. The result is shown by 5-1 in FIG. 5, the inner diameter R is 4 mm, and the axial length L is 100 mm.
The relationship between the filling time of the molding sand 6 and the acceleration in the space 9A of the test piece 9 made of the half-split cylindrical foamed molded product was obtained by an experiment, and the result is shown as 5-2 in FIG. From these 5-1 and 5-2, it was found that a hole having an inner diameter R of 4 mm can be filled with the molding sand in 60 seconds by an exciting force of 1.5 G. With a hole having an inner diameter R of 18 mm, the molding sand can be filled in a shorter time. Can be filled.

Further, as shown in FIG. 9, the result of using a three-dimensional vibration table using a vibration motor is shown. As described above, the filling of the molding sand 6 into the space 9A of the test piece 9 having the radius R of 18 mm was impossible. Although possible, it was impossible to fill the molding sand 6 into the space 9A of the test piece 9 having the radius R of 4 mm. Therefore, it can be seen that the vibrating device of the present invention can be filled in an extremely short time as compared with the conventional vibrating device. That is, according to the present invention, it is proved that the filling density of the molding sand 6 around the disappearing model 7 can be sufficiently ensured even if the disappearing model 7 has a complicated shape with lateral holes and downward faces. is doing.

[0016]

As described above, according to the present invention, a single piston reciprocating type vibration exciter is operated to generate a vibration force in the vertical and reverse directions. The acceleration characteristic of the vanishing model surface becomes regular corresponding to the table and the amplitude characteristic of the vanishing model surface. As a result, vibration is sufficiently transmitted to the foundry sand, its movement displacement is improved, the filling efficiency of the foundry sand is improved, and the horizontal movement of the foundry sand is facilitated by applying horizontal vibration. It improves the filling efficiency of foundry sand. Further, even if the vanishing model has a complicated shape having a lateral hole or a downward surface, there is an advantage that the packing density of the molding sand around the vanishing model can be sufficiently secured.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a vibrating device for vanishing model casting according to the present invention.

FIG. 2 is a plan view of the above.

FIG. 3 is a graph showing amplitude characteristics of a table and a disappearing model surface generated by the vibrating device of the present invention.

FIG. 4 is a graph showing acceleration characteristics of a table and a disappearing model surface generated by the vibrating device of the present invention.

FIG. 5 is a graph obtained by an experiment for the relationship between the filling time of the molding sand and the acceleration in the space of the test piece by the vibration device of the present invention.

FIG. 6 is a front view showing a conventional vibrating device for vanishing model casting.

FIG. 7 is a graph showing amplitude characteristics of a table and a disappearing model surface generated by a conventional vibration device.

FIG. 8 is a graph showing acceleration characteristics of a table and a disappearing model surface generated by a conventional vibration device.

FIG. 9 is a graph obtained by an experiment regarding the relationship between the filling time of the molding sand and the acceleration in the space of the test piece by the conventional vibration device.

FIG. 10 is a perspective view of the experimental device.

[Explanation of symbols]

 1 Machine Stand 2 Spring (Air Spring) 3 Table 4 Piston Reciprocating Vibration Machine 5 Casting Frame 6 Foundry Sand 7 Disappearance Model 11 Clamp 12 Vibration Motor

Claims (1)

[Claims] 1. A table, which is swingably arranged on a machine base via a spring, and one piston reciprocating type pressurizing machine, which is attached to the table and uses compressed air to vertically vibrate the table. For disappearing model casting, characterized by vibrating machine and vibrating motor fixed to opposite sides of the vibrating table in order to vibrate the table horizontally so that the vibrating table can be simultaneously vibrated vertically and horizontally. apparatus.