JPH10225762A - Method for removing core sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly remove core sand without using chemical method even in the case of being small diameter of an opening hole in a hollow part or complicate shaped recessed part in the inner peripheral surface in the hollow part by using a nozzle which can insert into the hollow part of a work and removes the sand core while injecting gas with a specific pressure from the tip part. SOLUTION: Firstly, the first nozzle 11 is faced to the one side of opening hole 3 in the hollow part 2 and shifted to the other side of opening hole 4 while injecting the high pressure air A having >=0.8 MPa from the injection hole 11a. In this result, the core sand S1 at the center of the hollow part 2 is detached. At the time of communicating both opening holes 3, 4, the second nozzle 12 is inserted into the hollow part 2 from the one side of opening hole 3 while inserting the high pressure air A from injection holes 12a, 12b and slowly rotating. By this method, the core sand S2 in the recessed parts 5 of annular grooves 6, 7, bypass holes 8, etc., is removed by detachment with the turbulance of the air A and the linked detachment of core sands mutually.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing core sand from a cast product (work) such as a hydraulic component having a hollow portion having a complicated shape.
It is a method of removing efficiently, especially when the opening is 10 mm in diameter.
The present invention relates to a method for removing core sand which is suitable for removing core sand attached to the inner peripheral surface of a hollow portion having a complicated shape with a diameter of not more than mm.

[0002]

2. Description of the Related Art Conventionally, a core forming a hollow portion of a work has to withstand the pressure of hot water, and also needs to have shrinkability and fire resistance. Therefore, a predetermined sand such as oil, dextrin, resin, etc. It is formed by core sand containing a binder, and after casting, it is subjected to vibration, shot blast, air blast, hydroblast, or a chemical method using a molten salt bath in which an oxidizing agent is added to a predetermined alkaline solution. As a result, core sand adhered to the inner peripheral surface of the hollow portion was removed.

[0003]

However, in a conventional mechanical method such as shot blasting, a grinding action is applied from the outside of the work. When the inner peripheral surface was provided with complicated concave portions such as grooves and holes, the core sand could not be completely removed.

For example, as shown in a work 1 shown in FIG. 4, a complicated concave portion 5 having an annular groove 6 and a communication hole 8 for communicating the annular grooves 7, 7 is formed in the hollow portion 2. In this case, first, in the first stage I, the work 1 is loaded into the shot blasting machine and rolled, and the work 1 is projected from the impeller 9 onto the shot material. At this time, the sand S0 attached to the outside is removed, but the core sand S1 in the hollow portion 2 is hardly removed.

[0005] Therefore, as a second stage II, the blasting material is charged into an air blasting machine, and a projection material is projected from a nozzle 10 facing the opening 3 of the hollow portion 2. At this time, the hollow part 2
The central core sand S1 can be removed somehow.

However, the nozzle 10 needs to have an opening of about 8 mm having a diameter of 5 mm or more to prevent the clogging of the projection material inside as the injection port 10a for injecting the projection material. If the diameter of 3.4 is less than 10 mm, the nozzle 10 cannot be inserted into the hollow portion 2 and the core sand S in the concave portion 5 such as the annular grooves 6 and 7 and the communication hole 8.
2 cannot be removed.

Therefore, it is necessary to remove the remaining core sand S2 by alternately repeating the chemical method and the vibration method. However, when the core sand S2 is removed by using the chemical method, The use of the oxidizing agent causes problems such as deterioration of the working environment and treatment of waste liquid, and further, poor working efficiency.

The present invention has been made to solve the above-mentioned problems, and can be used without using a chemical method even if the opening diameter of the hollow portion is small or a concave portion having a complicated shape is formed on the inner peripheral surface of the hollow portion. It is an object of the present invention to provide a method for removing core sand that can remove core sand smoothly.

[0009]

A core sand removing method according to the present invention is a core sand removing method for removing core sand adhered to a hollow portion of a work, wherein the core sand can be inserted into the hollow portion. so,
In addition, a nozzle capable of injecting a gas for removing core sand from an injection port at the tip is used, and the gas is 0.8 M from the injection port.
The nozzle is inserted into the hollow portion and removed while spraying at a pressure of Pa or more.

The outer diameter of the nozzle is preferably not more than の of the inner diameter of the hollow portion, and the nozzle is preferably formed of a flexible pipe material.

Further, one or a plurality of nozzles for injecting the gas of the nozzle may be provided on the side surface of the tip. In this case, the nozzle and the work are relatively rotated to form a center. It is desirable to remove child sand.

Further, there are two types of nozzles: a first nozzle provided with an injection port for injecting the gas on the tip end face, and a second nozzle provided with one or more injection ports for injecting the gas on the tip end face. First, using the first nozzle, remove at least the central core sand in the hollow portion of the core sand, and then, using the second nozzle,
The core sand attached to the concave portion in the inner periphery of the hollow portion of the core sand may be removed. In this case, the core sand is rotated while the second nozzle and the work are relatively rotated. It may be removed.

[0013]

The method for removing core sand according to the present invention uses a nozzle which can be inserted into a hollow portion of a work and which can eject gas for removing core sand from an injection port at the tip end. While injecting gas for core sand removal at a pressure of 0.8 MPa or more,
The nozzle is inserted into the hollow portion to remove core sand in the hollow portion.

That is, in the method for removing core sand according to the present invention, the core sand is removed by injecting a gas such as air from a nozzle orifice without using a conventional projectile. Since there is no need to consider issues such as clogging of the blast material, the outer diameter of the nozzle can be reduced, and the nozzle can be easily inserted even if the opening diameter of the hollow portion is small, and air or the like can be inserted. Is injected from the injection port at a high pressure of 0.8 MPa or more, so that the core sand can be easily blown off and removed. In addition, since gas such as air for removing core sand is ejected from the injection port at a high pressure of 0.8 MPa or more to remove core sand, a concave portion having a complicated shape is formed on the inner peripheral surface of the hollow portion. Even if it is formed, the gas for removing core sand easily penetrates into the concave portion, and the core sand in the concave portion can be removed.

Therefore, in the method for removing core sand according to the present invention, even if the opening diameter of the hollow portion is small or a concave portion having a complicated shape is formed on the inner peripheral surface of the hollow portion, the chemical method is not used. The core sand can be removed smoothly. In addition, since the core sand is removed by using a gas such as air instead of using a blast material, simple and inexpensive equipment can be used, and wear of the equipment can be prevented.

If the outer diameter of the nozzle is less than half the inner diameter of the hollow part, the core sand separated from the inner peripheral surface of the hollow part is prevented from interfering with the moving nozzle. From the gap between the surface and the inner peripheral surface of the hollow portion, the work can be easily discharged to the outside of the work, and the efficiency of the removing operation can be improved.

Further, if the nozzle is formed of a flexible pipe material, the nozzle can be easily bent and inserted along the hollow even if the hollow itself is complicatedly bent, The core sand that is bent intricately can also be easily removed.

Further, one or a plurality of nozzles for injecting gas from the nozzle may be provided on the tip side surface. When such a nozzle is used, an annular groove or the like is formed on the inner peripheral surface of the hollow portion. Even if the concave portion is provided deeply, the core sand attached to the inner peripheral surface of the concave portion of the hollow portion can be easily removed by inserting the nozzle into the hollow portion while injecting the gas for removing core sand from the injection port. When the nozzle and the work are relatively rotated during the removing operation, the core sand adhered to the entire inner peripheral surface of the concave portion can be easily removed.

Further, two types of nozzles are used: a first nozzle having an injection port for injecting gas at the tip end face, and a second nozzle having one or more injection ports for injecting gas at the tip end face. First, using the first nozzle, at least the central portion of the core sand in the hollow portion of the core sand is removed,
After that, if the second nozzle is used to remove the core sand attached to the concave portion in the inner periphery of the hollow portion of the core sand, the complicated shape provided in the hollow portion can be more completely removed. The core sand adhered to the inner peripheral surface of the recess can be more smoothly removed.

Of course, when the second nozzle is inserted into the hollow portion, the core sand adhering to the entire inner peripheral surface of the concave portion can be easily removed by relatively rotating the second nozzle and the work. Can be removed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

The removal method of the first embodiment will be described. As shown in FIG. 1, two types of nozzles, a first nozzle 11 and a second nozzle 12, are used.
The first and second nozzles 11 and 12 both inject high-pressure air A of 0.8 MPa or more, preferably about 1 MPa, as a gas for removing core sand.
1 is provided with an injection port 11a for injecting air A for removing core sand on the tip end surface, and the second nozzle 12 is
Air A for removing core sand is placed at two symmetrical locations on the side of the tip.
Are provided. Further, the first and second nozzles 11 and 12 have an outer diameter D1
The dimension is set to ２ or less, preferably １ ／ or less of the inner diameter d1 of the hollow portion 2 of the work 1.

The first and second nozzles 11 and 12 are connected to a high-pressure air supply source having a general-purpose compressor, a pressure-intensifying tank, and the like so that high-pressure air A can be injected.
The first and second nozzles 11 and 12 are supported by moving means such as a fluid pressure actuator such as an air cylinder and a gear device (not shown) so as to be able to move in the hollow portion 2 of the work 1. Further, the injection port 11a of the first and second nozzles 11 and 12
-As for the pressure of the air A injected from the 12a and 12b, the higher the pressure, the easier the core sand can be removed. However, the air pressure of a general-purpose compressor is usually 0.5 MPa, and from the viewpoint of not increasing the equipment cost, it is preferable to connect a general-purpose pressure-increasing tank to increase the pressure. The upper limit is set to about 1 MPa.

The operation of removing the core sand S1 and S2 in the hollow portion 2 of the work 1 according to the first embodiment will be described. First, sand (not shown) attached to the outside is removed by a conventional method such as shot blasting. deep.

First, as shown in FIG. 1I, in a first stage, the first nozzle 11 is opposed to one opening 3 of the hollow portion 2 and then the high pressure air A of 1 MPa is supplied from the injection port 11a. While spraying the first nozzle 11 toward the other opening 4 side.
To move.

Then, by the air A injected at a high pressure,
The core sand S1 in the center of the hollow portion 2 is peeled off.
The core sand S1 may be separated not only from the air A but also from the separated core S1 interfering with the attached core sand S1 and separating the attached core sand S1 in a chain. .

When the first nozzle 11 enters the hollow part 2, the outer diameter D 1 of the first nozzle 11 is changed to the inner diameter d 1 of the hollow part 2.
The core sand S1 can be easily discharged to the outside of the work 1 through the periphery of the nozzle 11, and the core sand S1 can be removed smoothly. Can be.

Thereafter, when the openings 3 and 4 are in communication with each other, in the second stage, as shown in II of FIG.
While injecting high-pressure air A of 1 MPa from a · 12b,
The second nozzle 12 is inserted into the hollow portion 2 from one opening 3 while slowly rotating. In this case, the second
The work 1 may be rotated instead of the nozzle 12.

Then, not only the portion where the injected air A collides immediately, but also the separation due to the turbulence of the air A and the above-described chain separation, as shown in FIG. The core sand S2 in the recess 5 such as 7 and the communication hole 8 is removed.

Incidentally, the inner diameter d1 of the hollow portion 2 is 10 mm,
Length L1 is 40 mm, inner diameter d2 at the bottom of annular groove 7 is 30 m
m, the width L2 of the annular groove 7 is 4 mm, and the maximum inner diameter d3 of the communication hole 8
Core S1 ・ S of work 1 which is a hydraulic component with
2 so that the outer diameter D1 is 2 mm and the injection port 11 is removed.
Using the first and second nozzles 11 and 12 having the diameters of a, 12a, and 12b of 1 mm, in the first and second stages as described above,
When the removal operation was performed, each process took 15 seconds to remove core sand S
1. S2 could be completely and cleanly removed. In addition,
The core sand S2 in the communication hole 8 could be completely removed by rotating the nozzle 12 for 5 seconds at the position of the nozzle 12 indicated by a two-dot chain line in II of FIG. The nozzle 11
-When the pressure of the air A supplied to 12 was less than 0.8 MPa, the core sand S2 sometimes remained in the communication hole 8 and the like.

The removal method according to the second embodiment will be described. As shown in FIG.
Is formed with three blind holes 18 (18A, 18B, 18C) as recesses between the openings 16 and 17 at both ends, and adheres to the inner peripheral surfaces of the blind holes 18A, 18B, 18C. The core sand S3 is removed. This second
The nozzle 20 used in the embodiment is provided with one injection port 20a for injecting high-pressure air A on the side surface of the tip, and is connected to a high-pressure air supply source such as a compressor (not shown) and not shown. It is supported by moving means. Also, the outer diameter of the nozzle 20 is set to 1/3 or less of the inner diameter of the hollow portion 15.

In the second embodiment, the nozzle 20 is inserted into the hollow portion 15 of the work 14 while injecting the high-pressure air A from the injection port 20a, and the arrangement position of the injection port 20a coincides with the blind holes 18A, 18B, and 18C. At this time, the movement of the nozzle 20 is stopped at the positions i, u, as appropriate.

Then, the high-pressure air A flows through the blind holes 18A and 18B.
-The core sand S3 clogged in the 18C collides, the core sand S3 peels off, and further, the core sand S3 peels off sequentially due to the interference of the peeled core sand S3, etc. Opening 3.4
Will be discharged smoothly.

In the hollow portion 15 of the work 14,
When the openings 16 and 17 are closed with core sand, while rotating the nozzle 20 or the work 14 in the circumferential direction,
The nozzle 20 is inserted through one of the openings 16 to remove the core sand, and in the middle thereof, the blind holes 18A, 18B, 1
The core sand S3 may be eliminated by stopping at the position 8C. Alternatively, after inserting a nozzle having an injection port on the tip end surface such as the first nozzle 11 used in the first embodiment into the hollow portion 15 to remove the core sand disposed in the center of the hollow portion 15 Using the nozzle 20, the blind hole 18A
The core sand S3 in 18B / 18C may be eliminated.

In the removing method of the third embodiment, as shown in FIG. 3, the hollow portion 23 of the work 22 is provided with three curved fine holes 24 (24A, 24B, 24C) as concave portions. The core sand S4 attached to the inner peripheral surfaces of the pores 24A, 24B, and 24C is removed. This third
The nozzle 26 used in the embodiment has an injection port 26a for injecting the high-pressure air A on the tip end surface. Nozzle 2
Numeral 6 is formed of a flexible pipe material such as a soft synthetic resin such as polyamide, and is connected to a high-pressure air supply source such as a compressor (not shown) and supported by moving means (not shown). Further, the outer diameter of the nozzle 26 is set to be not more than 1/3 of the inner diameter of the fine holes 24A, 24B, 24C of the hollow portion 23.

In the third embodiment, while the high pressure air A is injected from the injection port 26a, the nozzle 26
-It will be inserted into 24B and 24C, and core sand S4 will be removed. At this time, the nozzle 26 has flexibility,
Since it bends smoothly along the pores 24A, 24B, 24C, the core sand S4 in the pores 24A, 24B, 24C can be removed smoothly.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a removal method according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a removal method according to a second embodiment.

FIG. 3 is a diagram illustrating a removal method according to a third embodiment.

FIG. 4 is a diagram illustrating a conventional removal method.

[Explanation of symbols]

1.14.22 ... work, 2.15.23 ... hollow part, 5.18.24 ... recess, 10.20.26 ... nozzle, 10a / 11a / 12a / 12b / 20a / 26a ... injection port, 11 ... 1st nozzle, 12 ... 2nd nozzle, S1, S2, S3, S4 ... core sand, A ... (gas for core sand removal) air.

Continued on the front page (72) Inventor Shigeru Tanahashi 51, Shinmei, Ufukuji, Nishiharu, Nishiharu, Nishi-Kasugai, Aichi Prefecture Inside (72) Inventor, Masatomo Watanabe Ufuji, Nishiharu, Nishiharu, Nishiharu-cho, Aichi Shinmei 51 Shinto Breather Co., Ltd.

Claims (7)

[Claims] 1. A method for removing core sand adhered to a hollow portion of a work, comprising: a core sand-removable gas that can be inserted into the hollow portion and that is removed from an injection port at a tip end. A method for removing core sand, comprising: inserting a nozzle into the hollow portion and removing the gas while ejecting the gas from the ejection port at a pressure of 0.8 MPa or more using a nozzle capable of ejecting core sand. . 2. The method for removing core sand according to claim 1, wherein the nozzle is formed of a flexible pipe material. 3. The method for removing core sand according to claim 1, wherein the outer diameter of the nozzle is not more than １ ／ of the inner diameter of the hollow portion. 4. The method for removing core sand according to claim 1, wherein one or a plurality of nozzles for injecting the gas of the nozzle are provided on a tip side surface. 5. The method for removing core sand according to claim 4, wherein the nozzle and the work are relatively rotated. 6. A first nozzle provided with an injection port for injecting the gas at a tip end face, and a second nozzle provided with one or more injection ports for injecting the gas at a tip end face.
Using the type, the first nozzle is used to remove at least a central portion of the core sand in the hollow portion of the core sand, and thereafter, the second nozzle is used to remove the hollow portion of the core sand. 3. The method for removing core sand according to claim 1, wherein the core sand attached to the concave portion on the inner periphery of the portion is removed. 7. The method according to claim 6, wherein the second nozzle and the work are relatively rotated.