JP2004174603A - Method of removing sand from hollow casting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means of sufficiently removing core sand from the surface of a casting having a complicated shape, e.g., with a bent hollow part without requiring much time and labor. <P>SOLUTION: In the method of removing sand from a hollow casting, an impact application material is charged to the hollow part of the casting, and the casting is swung. The impact application material consists of metallic balls having diameters of about Φ3 to 30 mm, and consists of metallic balls having the same size, or of a mixed material of metallic balls having different sizes. The frequency in the swinging is about 5 to 20 Hz, the twist width is about 30 to 200 mm, and the total swinging time is about 1 to 120 min. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing sand from the surface of a casting having a hollow formed by a wall.
[0002]
2. Description of the Related Art When a molded body having a space inside (that is, having a hollow portion) like a gutter-like body or a pipe is manufactured by a simple casting method, a mold is used in addition to a main mold. A core is used to create the hollow.
For example, to obtain a hollow casting 30 shown in FIG. 3, a mold 20 shown in FIG. 2 (perspective view) and FIG. 5 (cross-sectional view) can be used. The mold 20 includes an upper mold 21, a lower mold 22, and a core 23, and has a cavity 29 corresponding to a hollow casting 30. As the core 23, for example, a material obtained by solidifying sand with a thermosetting resin or the like and forming it into a desired shape is used. Generally, after pouring a molten metal into the cavity 29 and solidifying, the upper mold 21 and the lower mold 22 are opened. The hollow casting 30 can be obtained by disintegrating the core 23.
However, when the shape of the hollow casting is complicated, sand generated when the core is collapsed is not easily removed, particularly from the casting surface forming the hollow portion, and this removal is troublesome. There was such a problem.
Hereinafter, an intake manifold, which is one of the ventilation parts for vehicles, will be described as an example of a hollow cast having a complicated shape and problems will be described (see Patent Document 1 as a prior art document regarding the intake manifold). . The intake manifold is an air supply pipe formed by using, for example, an aluminum alloy as a main raw material and supplying air to each cylinder of the engine.
FIG. 4 is a perspective view showing one embodiment of an intake manifold. The intake manifold 40 is a supply pipe for a four-cylinder engine formed by dividing four branch pipes 49 connected to each intake port of a cylinder of the engine from the surge tank 48. The hollow portion 46 of the intake manifold 40 is a portion through which a mixed gas (such as gasoline and air) passes, and is formed using a core.
In the case of a hollow casting having a more complicated shape, such as the intake manifold 40, the hollow portion formed by the core is bent, merged, and dispersed. Even if the core is broken by baking or the like, and then the core sand is to be removed, it takes time and effort to remove the sand particularly from the casting surface forming the hollow portion.
[0008] Since core sand remaining on the casting surface is not easily removed by simple shot blasting, conventionally, sanding or beads are mixed and the mixture is projected at a predetermined pressure, or the air is removed. Means of spraying pressurized water underneath or by immersing the hollow casting in water, or means of vibrating the hollow casting itself by chipping, hammering, etc. are performed (prior to the method of removing core sand). See Patent Documents 2, 3, and 4 for technical literature). However, even with these means, in the case of a hollow casting having a bent hollow portion such as the intake manifold 40, core sand is not easily removed particularly from the bent hollow portion, which requires a great deal of trouble. I was
[0009]
[Patent Document 1]
JP-A-5-149204 [Patent Document 2]
JP-A-7-308751 [Patent Document 3]
Japanese Patent Application Laid-Open No. 9-182952 [Patent Document 4]
Japanese Patent Application Laid-Open No. H11-188777
As described above, the conventional problems have been explained by exemplifying an intake manifold as a hollow casting. However, the present invention has been made in view of these problems, and its object is to provide a simple shape. Even if the casting is a casting having a complicated shape such as a hollow portion being bent, even by providing a means for sufficiently removing core sand from the casting surface without taking time and effort. is there. The problems of the conventional method of removing core sand were reviewed and studied repeatedly, and as a result of studying to find a new method, it was found that the above-mentioned object was achieved by the following means.
[0011]
That is, according to the present invention, there is provided a method for removing sand from the surface of a casting having a hollow portion formed by a wall portion. A method for removing sand from a hollow casting, characterized by swinging the casting is provided. The method for removing sand from a hollow casting according to the present invention is useful when the surface of the casting from which sand is to be removed is a wall surface forming a hollow portion from which sand has not been easily removed conventionally.
In the present invention, the hollow portion into which the impact-imparting material is introduced may be a part or all of the hollow portion of the casting. That is, according to the method for removing sand from a hollow casting according to the present invention, the impact caused by the impact imparting material oscillating in the hollow portion into which the impact imparting material is thrown and colliding with the wall forming the hollow portion is used. It is also possible to remove the sand in the hollow portion where the application material is not charged.
In the method for removing sand from a hollow casting according to the present invention, the hollow portion into which the impact-imparting material is to be charged is not limited. For example, in a casting having a plurality of hollow portions having various sizes or diameters. When the impact-providing material is injected into a hollow portion having a large space or a large-diameter hollow portion, when the impact-providing material is swung, the impact is more likely to be generated more effectively, and the hollow portion constituted by a smaller space. The purpose of sand removal can be achieved without introducing an impact-providing material into the small-diameter hollow portion.
In the present invention, when the casting to be subjected to sand removal is a vehicle ventilation system component having a cooling water channel as a part of the hollow portion, the hollow portion into which the impact-imparting material is charged is formed by It is preferably a hollow portion excluding a cooling water channel. Even so, the sand in the cooling channel can be easily removed. Examples of the vehicle ventilation system component having a cooling water passage as a part of the hollow portion include a cylinder head, an intake manifold, an exhaust manifold, and the like. In the cylinder head, the hollow portion excluding the cooling water channel corresponds to an intake port and an exhaust port.
In the method for removing sand from a hollow casting according to the present invention, it is preferable that the frequency of the rocking be about 5 to 20 Hz. Further, it is preferable that the swing width of the swing is approximately 30 to 200 mm. Further, it is preferable that the total swing time of the swing is approximately 1 to 120 minutes.
In the present invention, the impact imparting material is composed of metal spheres having a diameter of approximately φ3 to 30 mm, and is preferably composed of a mixture of metal spheres having the same diameter or different diameters.
The present invention is suitable when the main material constituting the casting is cast iron or an aluminum alloy for casting.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the method for removing sand from a hollow casting according to the present invention will be described in detail, but the present invention should not be construed as being limited to the following description. Various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope.
The present invention is a method for removing sand from the surface of a casting having a hollow portion formed by a wall portion, and in particular, a wall portion forming a hollow portion which has conventionally required a lot of time for sand removal. This is a method that exhibits excellent effects in that sand can be easily removed from the surface (referred to as the inner surface of the hollow casting). In the present specification, the surface of the casting does not indicate only the casting surface, that is, the surface as cast. Since the casting surface is a surface that often has small irregularities and takes time to remove sand, the present invention is useful for removing sand from the casting surface, but the present invention is not limited to this case, For example, this includes a case where it takes time to remove sand from the surface as a result of performing predetermined processing on the surface. In addition, the sand to be removed refers to sand remaining mainly on the surface of the casting after the core of sand is broken, but according to the present invention, it is possible to remove foreign substances equivalent to sand other than sand. is there. For example, a solidified coating agent can be removed. Further, in this specification, removing sand from the wall surface forming the hollow portion is also referred to as removing sand from the inner surface of the hollow casting, or simply removing sand from the hollow portion. Since the sand does not exist in the hollow space, it is synonymous with any description.
The method for removing sand from a hollow casting according to the present invention is characterized in that an impact imparting material is introduced into the hollow formed by the wall to swing the casting. The impact imparting material having a hardness suitable for the material forming the hollow casting is put into the hollow portion formed by the wall portion, the opening is closed, and the preferable swing width, frequency, and swing time described below are used. By swinging the hollow casting, the impact imparting material repeatedly collides over the entire inner surface of the hollow casting. As a result, when the impact imparting material causes an impact / vibration throughout the hollow casting, all the sand including the sand remaining on the inner surface of the hollow casting jumps out of the casting surface due to the impact / vibration. Is discharged.
It is apparent from the fact that sand is not easily removed by conventional chipping and hammering, because it takes time and effort to remove sand only by continuous vibration. Even if the whole vibrates, sand is not discharged from the casting surface. Sand removal requires an impact. In conventional chipping and hammering, sand may not be easily removed particularly at a place away from the point of vibration. However, in the method for removing sand from a hollow casting of the present invention, the impact imparting material is free in the hollow part. , Causing an impact over the entire inner surface of the hollow casting, so that sand can be easily removed on the entire casting surface including the entire inner surface of the hollow casting.
Further, in the conventional chipping and hammering, the impact is greatly different between the point of vibration and the place away from the point of vibration, and the impact is too large at the point of vibration and the casting may be cracked. In the method for removing sand from a hollow casting according to the present invention, the impact imparting material moves freely in the hollow portion and generates substantially the same impact over the entire inner surface of the hollow casting, so that the casting does not crack.
In swinging the hollow casting, the opening of the hollow part is closed, but it is preferable to form an external space at the end following the hollow part. If the opening of the hollow portion is closed without forming the external space, it is difficult to move the impact imparting material to the opening end, and the sand may accumulate at the opening end, which is not preferable.
In addition, sand can be removed from a hollow portion into which no impact-imparting material is introduced by an impact / vibration generated by introducing an impact-imparting material into some of the hollow portions and swinging the impact-imparting material. For example, in the cylinder head 152 shown in FIGS. 1 (a) and 1 (b), the intake port 154 and the exhaust port 155 are formed as closed spaces, into which an impact imparting material is charged, and the cylinder head 152 is swung. By doing so, it is possible to remove sand remaining in the cooling water channel 156 which is a plurality of small hollow portions into which the impact imparting material is not charged. 1 (a) and 1 (b) are cut-away views for explanation, and the cylinder head 152 which is not cut has a manifold connection port 157 (intake or exhaust) and a valve port (intake or exhaust). An intake port 154 and an exhaust port 155 having an opening end 158 form a hollow portion. Therefore, if these open ends are closed with a cover, a closed space including the intake port 154 and the exhaust port 155 can be formed.
It is preferable that the impact imparting material is made of a metal sphere having a diameter of at least approximately 3 to 30 mm. Metal balls having the same diameter may be used, or a mixture of metal balls having different diameters may be used. Further, metal particles, abrasives or abrasives, etc. may be mixed.
More preferably, it is a mixture of metal spheres having at least different diameters. By mixing impact-imparting materials having different sizes, the impact-imparting materials are more evenly and repeatedly moved to the inner surface of the hollow casting without leaking, and the large metal balls are sufficient to remove sand to the inner surface of the hollow casting. This is because an impact can be caused.
The diameter of the metal sphere or the material forming the metal sphere may be determined in consideration of the material forming the hollow casting, the cross-sectional area of the hollow portion of the hollow casting, and the like. ３０30 mm, but is not limited. For example, when the hollow casting is a vehicle ventilation system component made of an aluminum alloy, a steel ball or a stainless steel ball having a diameter of 10 to 20 mm can be preferably used.
It is preferable that the impact-imparting material is introduced so as to have a volume of about 5 to 50% of the volume of the hollow portion of the hollow casting. In addition, the hollow portion into which the impact imparting material is charged may not be the entire hollow portion of the casting, but is preferably formed over the entire casting. The impact imparting material moves freely in the hollow part, ensuring that the number of collisions between the impact imparting material and the inner surface of the hollow casting is ensured, and the impact / vibration caused by the impact is sufficiently applied to all inner surfaces of the hollow casting. In order to be given.
Hereinafter, the swinging conditions of the hollow casting for generating an impact by colliding the impact imparting material with the inner surface of the hollow casting will be described. The present invention does not limit the swing condition, but is more preferably as follows.
The frequency is preferably about 5 to 20 Hz. This is for ensuring the number of collisions per unit time between the impact imparting material and the inner surface of the hollow casting. If the vibration frequency is less than 5 Hz, the number of collisions between the impact imparting material and the inner surface of the hollow casting is not secured, and the impact caused by the collision does not remove the sand quickly and sufficiently, which is not preferable. Further, although depending on the number of impact imparting materials (for example, steel balls), sand can be removed at a vibration frequency of about 20 Hz.
The swing width of the swing is preferably about 30 to 200 mm. This is because the number of collisions per unit time between the impact applying material and the inner surface of the hollow casting is ensured by appropriately setting the moving range of the impact applying material in the hollow portion. When the swing width is less than 30 mm, the number of collisions between the impact imparting material and the inner surface of the hollow casting is not ensured, and the impact caused by the collision does not remove the sand quickly and sufficiently, which is not preferable. Further, even if the swing width is larger than 200 mm, the time during which the impact imparting material is in contact with the inner surface of the hollow casting only increases, the number of collisions between the impact imparting material and the inner surface of the hollow casting does not increase, and sand is easily removed. No.
Further, the total swing time of the swing is preferably about 1 to 120 minutes. This is to ensure the total number of collisions between the impact imparting material and the inner surface of the hollow casting. If the total swing time is less than 1 minute, the total number of collisions between the impact imparting material and the inner surface of the hollow casting is not ensured, and the sand on the inner surface of the hollow casting may not be sufficiently removed. Also, depending on other conditions, since the total swing time is about 120 minutes and the sand is completely removed, even if the swing is longer, the effect on the time required for manufacturing the hollow casting is not improved. Absent.
In the method for removing sand from a hollow casting according to the present invention, it is preferable to select the direction in which the hollow casting is rocked so that the number of collisions between the impact imparting material and the inner surface of the hollow casting is ensured. The direction may be determined by the shape of the hollow part of the hollow casting. For example, when swinging the intake manifold 40 shown in FIG. 4, it is not preferable to swing the intake manifold 40 in the longitudinal direction of the hollow portion 46 of the intake manifold 40. This is because the ratio of the smoothing material having a longer moving distance in the hollow portion 46 is increased, and the number of collisions between the smoothing material and the inner surface of the hollow casting due to the swing is reduced. A preferred swing direction when swinging the intake manifold 40 is, for example, a direction indicated by an arrow R shown in FIG. It is also preferable to change the direction during rocking.
[0034]
As described above, according to the present invention, not only when the shape of the hollow casting is simple, but also when the hollow casting is complicated such that the hollow portion is bent, The core sand can be easily and sufficiently removed from the surface of the hollow casting, and a clean hollow casting from which the core sand has been removed can be obtained.
[Brief description of the drawings]
FIGS. 1 (a) and 1 (b) are views in which a cylinder head which is an example of a hollow casting is cut, and FIG. 1 (a) is a side view when a cylinder head facing surface is a lower side. FIG. 1B is a diagram showing the cylinder head facing surface (the lower surface in FIG. 1A).
FIG. 2 is a perspective view showing an example of a mold for a hollow casting.
FIG. 3 is a perspective view showing an example of a hollow casting.
FIG. 4 is a perspective view showing one embodiment of an intake manifold which is an example of a hollow casting.
FIG. 5 is a sectional view of the mold for a hollow casting shown in FIG. 2;
[Explanation of symbols]
20 mold, 21 upper mold, 22 lower mold, 23 core, 24 main mold, 29 cavity, 30 hollow casting, 35 wall, 36 hollow part, 40 intake manifold, 45 Wall part, 46 hollow part, 48 surge tank, 49 branch pipe, 152 cylinder head, 154 intake port, 155 exhaust port, 156 cooling water passage, 157 manifold connection port, 158 valve port.

Claims (8)

A method for removing sand from the surface of a casting having a hollow portion formed by a wall portion,
A method for removing sand from a hollow casting, wherein an impact imparting material is charged into the hollow portion to swing the casting. The method for removing sand from a hollow casting according to claim 1, wherein the surface of the casting is a wall surface forming the hollow portion. The method for removing sand from a hollow casting according to claim 1, wherein the hollow portion into which the impact imparting material is charged is a part or all of the hollow portion of the casting. The said casting is a ventilation part for vehicles which has a cooling water channel as a part of the said hollow part, and the hollow part into which the said impact-imparting material is thrown is a hollow part except the said cooling water channel. Sand removal method for hollow castings. The method for removing sand from a hollow casting according to claim 1, wherein a frequency of the swing is approximately 5 to 20 Hz. The method for removing sand from a hollow casting according to claim 1, wherein the swing width of the swing is approximately 30 to 200 mm. The method for removing sand from a hollow casting according to claim 1, wherein the total swing time of the swing is approximately 1 to 120 minutes. The hollow according to any one of claims 1 to 7, wherein the impact-applying material is formed of a metal sphere having a diameter of approximately φ3 to 30 mm, and is a mixture of metal spheres having the same diameter or metal spheres having different diameters. Sand removal method for castings.

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