JPH0777660B2 - Method and apparatus for preventing dry powder from flowing down - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for preventing a dry powder or granular material from falling due to its own weight.

[0002]

[Prior art]

(1) For example, the peep nozzle that is widely used in mold making means has a special structure because when molding a molding material (casting sand) moistened with liquid resin or the like, the molding material does not drop due to its own weight. Used without and. on the other hand,
Since a dry molding material such as a resin coated sand (R.C.S.) falls by its own weight, various peep nozzles provided with a shielding mechanism at the lower end of the blowing nozzle have been proposed to prevent falling.

(2) Various types of dry molding material blowing nozzles are known, and all of these known ones have a shielding mechanism for preventing the molding material from flowing down at the lower end of the nozzle. It is also known that not only the shielding mechanism is worn but also the mechanism becomes a resistance when the molding material is blown, and the filling property of the molding material into the molding space is not uniform.

(3) The inside of the blow head for blowing the molding material is pressurized when the molding material is blown, but the inside of the blow head is kept at a negative pressure except at the time of molding to shield the lower end of the blowing nozzle. It has also been proposed not to provide (Jitsuko Sho 56-30.
No. 81).

[0005]

As a result of various tests conducted by the present inventors on the known technique of the above item (3), it has been found that the above system has the following problems: 1) Inside the blow head Due to the air flow resistance of the molding material, a large negative pressure power source is required to generate a negative pressure in the blow head to the extent that the molding material does not flow down from the lower end of the peep nozzle. 2) Since the distances to the lower ends of many peep nozzles provided in the blow head are not constant, it is not possible to maintain the negative pressure at the lower end of each peep nozzle even. For example, at a location with a high negative pressure level, even after the completion of blowing, even the molding part of the molded article (mold or core) will be sucked off and become a molded article with a "feeding" defect, while at a location with a low negative pressure level, Even by a mechanical pressing shaping method using a shaping pin or the like, an extra protrusion is formed on the molding surface of the molded product, and the work of correcting the molding surface is necessary. 3) Only by reducing the negative pressure in the blow head, the negative pressure level at the lower end of each peep nozzle varies in each molding process, and a desired molded product cannot be stably obtained.

[0006]

Means for Solving the Problems The present inventors have conducted various examinations and experiments as a result of solving various deficiencies of the known art as described above,
The present invention is to develop a method and apparatus for preventing a dry powder or granular material from flowing down, and a technical configuration of the present invention is to form a molded product using the dry powder or granular material, and At least one of the blowing nozzles attached to the blowing port or the blow plate sucks a negative pressure in the vicinity of the powder or granular material blowing port to reduce the negative pressure.
Blow plate blow-in opening and opening in a molding mechanism using a dry powder or granular material, characterized in that the powder or granular material is held in a blowout path, Flow-through of dry powder or granules, characterized in that a large number of negative pressure suction slits or air vents are provided facing or surrounding the powder or granules flow hole of the air blowing nozzle or the peep nozzle. It is in the prevention device, and by adopting such a technical configuration, the power of the negative pressure source is saved, the level of the negative pressure at the lower end portion of each peep nozzle is almost even and stabilized, and Each negative pressure level can be finely adjusted, the remaining amount of molding material on the molding surface of the molding product is equalized, mechanical pressure shaping becomes easy, the accuracy of the molding product is improved, and the molding material path in the nozzle There is no need to install a shield on the mold, and molding to a molding space The improved filling property and high density, have found that can achieve equal various actions and effects to further reduce the blowing process.

The method of the present invention and the apparatus of the present invention will be described in detail with reference to the accompanying drawings showing specific examples of the present invention.

FIG. 1 is a vertical cross-sectional view showing an example of the present invention. Reference numeral 1 is a nozzle body, 2 is a nozzle tip portion, and 4 is a packing provided on the lower surface thereof. The nozzle body 1 is provided with a connection port V1 to the negative pressure source, and inside the connection port, an air vent 3A is arranged facing the molding material blowing hole, and the opposite side thereof is also air vent. May be provided, or the plug 5 may be closed as shown in the drawing.

M1 is a screw portion for fitting and fixing the nozzle body 1 to a blow plate (not shown), and M2 is a screw portion for fitting and fixing the nozzle tip portion 2 to the nozzle body 1. The above-mentioned fitting and fixing means are not limited to screw-type fitting, and other means may be used.

The length 1 of the nozzle tip portion 2 is appropriately determined according to the shape of the molding cavity of the molding die, and a suction air flow control valve or the like is arranged between the negative pressure source and the negative pressure source as necessary. Just set it up.

FIG. 2 shows a structure which is almost the same as that of the example of FIG. 1, but facilitates the attachment / detachment of the air vent, and at the outer peripheral side of the cylindrical air vent 3B, a cavity is formed over the entire circumference. The portion 20 is provided, and the connection ports V1, are provided on both sides of the molding material blowing hole.
By connecting V2 in a communicating manner and connecting the connection ports V1 and V2 to each other, V1 is connected to the negative pressure source, and V2 is connected in series to the negative pressure source connection port of another adjacent peeping nozzle. It is possible to simplify the piping for connecting the negative pressure source to the peep nozzle.

With the structure of this example, the surface area of the air vent is large, the opening ratio of the ventilation openings (for example, the slit group) is large, and the pressure loss at the time of negative pressure suction can be reduced.

FIG. 3 is a longitudinal sectional view in which an air vent 3B similar to that in FIG. 2 is applied to an open type nozzle (a blowing nozzle of a type that does not have a nozzle tip portion like a peep nozzle), and the same reference numerals as those in FIG. The same member is shown, and 2'is a plug for attaching and detaching and fixing the air vent 3B.

4 to 6 show another embodiment of the present invention in which a negative pressure suction port is provided in the blow plate, the suction port communicates with the same air vent as in FIG. 2, and the air vent is provided in the blow plate. It is a longitudinal cross-sectional view showing a numerical example. In these drawings, the same reference numerals as those used in the above example represent the same members.

In FIG. 4, the nozzle body 1 is an open type nozzle fitted to the blow plate 7, and the packing 4
Is provided around the lower end surface of the blower so as to surround the blow-in port. The air vent 3B is fitted in the blow-in port as shown in the figure, and
Reference numeral 1 is a retaining ring for the air vent 3B. Reference numeral 8 denotes a molding material flow-down prevention plate provided directly above the blow port and inside the blow head (not shown), which stops the flow of the molding material (dry state) to an extremely small amount according to the angle of repose. Air vent 3
A hollow portion 20 is provided around the outer circumference of B, and the hollow portion is communicated with a negative pressure suction mechanism via a negative pressure suction port 22. Although the open-type blowing nozzle has been described above, the peeping nozzle 2 may be provided at the lower end portion as shown by a broken line in FIG.

FIG. 5 is a vertical sectional view showing another example in which an air vent is provided in the blow plate. In this example, an air vent 3B is arranged in the middle of the negative pressure suction port as shown in the drawing, and the negative pressure suction port is provided. This is an example in which the end face of 22 is opened to the blow hole. Although the illustrated example shows an example in which it is provided only on one side of the blow hole, it may be provided on both sides (communication with adjacent blow nozzles, etc.), and packing, peeping nozzle, etc. can be arranged with broken lines. Is also shown.

FIG. 6 shows a blow plate 7 and an open type nozzle 1.
It is a partial longitudinal cross-sectional view of an example in which a slit 23 for negative pressure suction is provided between and. Naturally, the slit 23 is a minute gap that does not allow the powder or granules as a molding material to pass through, and is provided around the blow hole, and is communicated with the negative pressure suction port provided in the blow plate 7. There is. In this example as well, the peeping nozzle 2 may be arranged downward as shown by the broken line.

FIG. 7 shows the air vent 3 on the molding material flow prevention plate.
It is a partial longitudinal cross-sectional view showing an example in which C is provided. The downflow prevention plate 8 is provided with a suction port 22 communicating with a negative pressure suction mechanism, and is arranged directly above the blow-in port of the blow plate 7 and with the slit of the air vent 3C communicating with the suction port 22 facing downward. After the blowing of the molding material, a negative pressure is applied through the air vent 3C so that the molding material in the blowing port (and the peep nozzle) is held without dropping.

In each of the above specific examples, the inside of the blow head can be slightly depressurized, but since a large amount of molding material is present in the blow head, the ventilation resistance is large. The factors that cause instability or insufficient decompression are insignificant, and a stable function can be maintained in the blowing nozzle.

8 to 11 are partial vertical sectional views showing an example of a molding process using the peep nozzle shown in FIG.

In FIG. 8, the peep nozzle attached to the blow plate 7 peeks (enters) the blow-in port 10 of the molding die, and the lower end of the nozzle tip 2 reaches the shape surface of the molding cavity 12.
The state where the dry molding material 6 is blown into the molding cavity 12 is shown. Blow head, blow plate outline, molding die outline,
The negative pressure source connection pipes and the like are not shown.

FIG. 9 shows a state in which the blow head and the peep nozzle are separated from the molding die, and the negative pressure source connection port V1 is connected to the negative pressure source V by a pipe (not shown). The molding material blowing path inside the peep nozzle is sucked by the negative pressure source V, and the negative pressure holds the dry molding material in the blowing path to prevent the material from flowing down. In order to prevent a large amount of molding material from flowing down when the negative pressure source is stopped due to some reason, a molding material flow prevention plate 8 is provided in the blow plate.

FIG. 10 shows a state of the molded product 13 (mold / core, etc.) after the peep nozzle is removed from the molding die. The molding material at the lower end of the peep nozzle becomes a slight protrusion S and remains in the molded product shape portion. This blow mark S must be left in a convex shape in order to shape the surface of the molded product. The concave shape causes so-called "feeding" defects on the surface of the molded product.

FIG. 11 shows a shaping process, in which the blow-in trace projection S is pressed by the shaping pin 15 to shape the surface according to the shape of the molded product. If the amount of blow-in traces S is large, the portion does not match the shape surface even if pressed by the shaping pin 15, and the portion must be corrected after taking out the molded product from the molding die. If the amount of blow-in protrusion S is small, even if pressed by the shaping pin 15, the entire surface of the portion will not be smooth and a molding material will be partially missing, resulting in deterioration of the quality and accuracy of the molded product. It is well known to those skilled in the art that molded articles with the "giving" defect cannot be used.

The amount of the blow mark S can be set to an optimum condition by increasing or decreasing the length 1 of the nozzle tip 2 and increasing or decreasing the amount of negative pressure suction air (dynamic negative pressure).

[0026]

【The invention's effect】

(1) By adopting a configuration in which negative pressure suction is performed in the vicinity of the blowing nozzle, the power saving of the negative pressure source and the negative pressure effect are improved. (2) Since the negative pressure suction ports are individually provided to the individual blowing nozzles, the negative pressure level for each nozzle is substantially equalized and stabilized. (3) The amount of negative pressure air can be individually adjusted for each nozzle, and the negative pressure level of each nozzle can be finely set regardless of the positional relationship of the blowing nozzles. (4) Since the shape of the lower end of the nozzle of the molding material suction-held in the nozzle is stable and the amount of molding material rising to the shape of the molded product is equal for all nozzles, the portion corresponding to all nozzles is It became possible to shape the shape by aligning it with the mechanical surface. (5) Since no shielding (downflow prevention) is provided in the molding material blowing path in the peep nozzle, the replacement frequency due to wear of the peep nozzle is significantly reduced, and the molding material can be filled with high density in the molding cavity. And it was made uniform. In addition, the blowing time was shortened and the molding operation rate was improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an example of the present invention,

FIG. 2 is a vertical cross-sectional view showing another example of the present invention using a cylindrical air vent,

FIG. 3 is a vertical sectional view showing an example in which the present invention is applied to an open type nozzle,

FIG. 4 is a vertical sectional view of an example in which the present invention is applied to a blow plate,

FIG. 5 is a vertical sectional view of an example in which the present invention is applied to a blow plate,

FIG. 6 is a longitudinal sectional view showing another example of the present invention in which the suction port has a slit shape,

FIG. 7 is a longitudinal sectional view of a main part showing another example of the present invention in which an air vent is provided on the molding material flow prevention plate.

FIG. 8 is a longitudinal sectional view showing a state when a molding material is blown in using the peep nozzle of the present invention,

FIG. 9 is a vertical cross-sectional view showing a state where the peep nozzle is separated from the molding die;

FIG. 10 is a vertical cross-sectional view showing protrusions formed on the surface of a molded product blown into a molding die;

FIG. 11 is a vertical cross-sectional view showing a process of shaping a protrusion of a molded product,

[Explanation of symbols]

 1 Nozzle body 2 Nozzle tip 2'Fixing plug 3A, 3B, 3C, 3D Air vent 4 Packing 5 Plug 6 Dry molding material 7 Blow plate 8 Flow-down prevention plate 9 Upper mold 10 Mold material injection port 11 Lower mold 12 Molding Cavity 13 Molded product 14 Shaping plate 15 Shaping pin 20 Cavity 21 Retaining ring 22 Negative pressure suction port 23 Negative pressure suction slit V1 connection port V2 connection port M1 screw part M2 screw part S molding material projection

Claims (2)

[Claims] 1. When forming a molded product using a dry powder or granular material, a negative pressure is applied to each of the blow openings of the blow plate or at least one of the blow nozzles attached to the blow plate. The powder and granules are sucked into the blowout path by the negative pressure.
A method of preventing the powder from flowing down by its own weight when the blowing is stopped. 2. A molding mechanism using a dry powder or granular material,
A blow plate, a blow-off port, a blow-off type blowing nozzle or a peep nozzle, facing the powdery or granular material flow hole, or surrounding the flow hole, and providing a large number of negative pressure suction slits or air vents. A device for preventing dry powder from flowing down.