JP2001129653A - Manufacturing method of female screw and casting component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a female screw member of which the thread portion is not welded (fused) even if the female screw member is used as an insert and its casting components. SOLUTION: A chill block is arranged on the mold side end surface of a female screw member which cast together with the casting member as an insert. The surface area of heat radiation of the chill block is designed to be greater than the endothermic surface area of the female screw member adsorbing heat from molten metal. Further, a vent hole extending from the thread hole of the female screw member to the mold is provided in the chill block. Moreover, and air permeable is arranged on the end surface of the vent hole brought into contact with the mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of casting a female screw member used for a hanging tool or the like in the handling of a product after casting or in machining, assembling a product, etc. The present invention relates to a manufacturing method and a casting part.

[0002]

2. Description of the Related Art Conventionally, when a product after casting is handled by transporting or the like, in the case of a cast part in which hooks and wires for hanging tools cannot be easily attached, a hanging ring shape for hanging tools is provided on a side surface of the product at the time of casting. They are manufactured (cast) as a single piece and cut and removed at the final work point when the care of the product is completed to finish it into the desired product shape. In other words, such a suspension ring shape is generally removed at the time of casting material. In the machining and assembly departments, female screws for hanging tools such as eye bolts are provided by tapping at appropriate positions on the casting. Have been.

[0003] Usually, most castings that must be used after processing the internal thread are large and hinder handling, and the work of processing the internal thread also requires labor. As such remedies,
For example, JP-A-62-118961 discloses a method for forming a female screw portion of a cast product. FIG. 6 shows an example of this disclosure, in which a male screw member 22 is screwed into a female screw member 21 (the number is different from that of the published gazette), and the female screw member 21 is formed into a mold in the screwed state. 23 is buried and cast with the molten metal 24, and after the cast product is solidified, the male screw member 22 is replaced with the female screw member 21.
This is a method of forming a female screw part by removing the screw. Furthermore,
It is also described that if an alloy layer of iron and aluminum is provided on the surface of the female screw member 21, seizure of the female screw member 21 and the male screw member 22 does not occur during casting.

[0004]

However, when the temperature of the molten metal when the female screw member 21 is cast into a cast product is extremely high, or when the thickness of the screw portion of the female screw member 21 is smaller than the surrounding thickness, If the thickness of the cast product (the molten metal part) is too large, the amount of heat absorbed by the female screw member 21 from the molten metal 24 cannot be sufficiently dissipated to the mold side. is there. In particular, if even a part of the screw portion is welded, the male screw member 22 cannot be screwed, and the male screw member 22 protrudes from the casting 22a or 22b.
It was necessary to drill a prepared hole after drilling and re-thread the screw, which was inconvenient.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present inventor has developed a method of manufacturing a female screw portion in which a screw portion is not welded (fused) even when the female screw member is used as a cast-in, and a casting obtained by the method. I came up with providing parts.

[0006] Originally, this metal is used for a thick portion where the solidification of a cast product is delayed, and is used for absorbing heat of the molten metal to promote solidification and to prevent the occurrence of defects. Therefore, as a conventional idea, when performing as-casting, in order to complete the welding between the as-cast material and the molten metal at the time of solidification of the molten metal, the combined use of the as-casting and a metal having a cooling capacity was not considered. The inventor of the present invention has conceived of a method of manufacturing a female screw portion without melting it by using an abutment on an end face of the female screw member while performing a detailed experimental plan.

That is, according to a first aspect of the present invention, in a method of casting a female screw member into a casting, a metal is provided on an end face of the female screw member on a mold side, and a heat radiation surface area of the gold to the mold is provided. This is a method for producing a female screw portion in which the internal thread member is cast with a larger heat absorbing surface area for absorbing heat from the molten metal. Here, the heat radiation surface area is the total surface area of the metal in contact with the mold, and the heat absorption surface area is the total surface area of the female screw member in contact with the molten metal. It is better to provide fins or ribs on the gold to increase the heat radiation area as much as possible in order to improve the heat radiation to the mold, rather than to use a simple columnar shape. Further, it is better to dispose the fins and ribs on an abutment at a position as far as possible from the female screw member which is a cast-in material, so that heat radiation to the mold is better.

Next, a second invention of the present invention is a method for casting a female screw member into a casting, wherein a metal is provided on an end surface of the female screw member on the side of the mold, and the gold is provided on the corresponding gold. This is a method for manufacturing a female screw portion to be cast by providing a vent hole from a screw hole to a mold. When a high-temperature molten metal is cast into a mold provided with a female screw member, the air accumulated in the screw hole of the female screw member also becomes hot and expands, but a solid metal has an escape area for the expanded air having high heat. Absent. Furthermore, since the air has a lower thermal conductivity than the female screw member or the metal, the air is in a heat storage state at the time of cooling as a whole, and depending on the size of the female screw member, the thread portion is delayed in cooling and becomes a molten state, and the shape is changed. Easy to deform. Therefore, if a vent hole is provided from the screw hole to the mold, the air that has expanded at a high temperature after casting the molten metal can be discharged into the mold, and the cooling of the screw thread portion will not be delayed and the desired shape will be obtained. It is possible to obtain

In the case where a vent hole is provided in the gold, sand particles of the mold may enter the hole during molding, which may cause adhesion of sand particles to the thread surface of the female screw member and impede ventilation. In such a case, a cover or a plug is used with a gas-permeable member such as a piece of paper or the like on the end surface of the hole on the side in contact with the mold or in the hole to prevent sand from entering. If it is a combustible material such as a piece of paper, the combustible material will not be destroyed by the heat of the molten metal at the time of pouring, and will not hinder ventilation.
If the ventilation is not hindered, the entry of sand may be prevented by using a non-flammable material such as a wire mesh.

Further, the female screw member and the metal are integrally welded and cast. Since this metal is cast in the state of being buried in the sand that is a mold, there is no risk of its position shifting during casting.However, if the female screw member is not fixed to the mold side in advance by any means, it will be used when pouring. There is a possibility that it will deviate from a predetermined position due to the hot water pressure or the like. Therefore, the end face of the female screw member on the side of the mold and the metal are welded together. Welding may be performed all around the end face,
Casting should be limited to temporary welding (point welding).
It is easy to remove the metal after cooling.

A male screw having a relatively short length is provided at one end of the metal, and the male screw is screwed into the female screw of the female screw member to be cast. When the size of the female screw member is increased, the size of the metal for cooling it is inevitably increased. When both are integrated by welding, not only heavy but also complicated handling is required. In such a case, a male screw that can be screwed into the female screw is provided at one end of the metal, and the screw is assembled before the molding operation. The length of the thread portion of the male screw need not be longer than that of the male screw as long as it is long enough to allow screw-in assembly. Not only does welding work become unnecessary, but also when removing the metal, the metal is simply screwed and separated, so that the operation is simple.

When the number of castings per point of a casting part is small, casting is performed using a vanishing model. A model is manufactured by laminating or shaving the disappeared model material previously foamed into a desired shape. Thereafter, if the female screw member is embedded in a desired position of the model and cast, the cost of the model is lower than that of a model such as a wooden mold, and the mounting position of the female screw member can be freely selected.

Further, the female screw member is integrally cast using the above-described method of manufacturing the female screw portion to obtain a cast part. Since the cast part has a female screw shape at the time of completion of casting, it can be easily handled using hanging tools such as eye bolts regardless of the material, processing, assembly, etc. It is feasible.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail, but the present invention is not limited to these embodiments.

[0015]

Embodiment 1 FIG. 1 is a partial sectional front view showing a method for manufacturing a female screw portion according to a first embodiment of the present invention. An abutment 3 was provided on an end surface 2 of the female screw member 1 on the mold side. The female screw member 1 has a female screw 1a having a size of M20, a screw depth of 30 mm,
The pilot hole had a depth of 40 mm and was made of steel. In addition, this money 3
Has a shape in which two flanges 3b are provided on a cylindrical contact body 3a. The material was also steel. The basic dimensions of the gold main body 3a are 35 mm in diameter and 50 mm in length. The flange 3b has a thickness of 4.5 mm and external dimensions of 55 mm and 65 m.
m were integrally assembled to the metal body 3a by welding. At this time, the heat radiation surface area of the metal 3 to the mold 4 is about 2 of the heat absorption surface area where the female screw member 1 absorbs heat from the molten metal 5.
It was twice.

Next, the metal screw member 1 and the metal shell 3 are welded to the end face 2 of the female screw member 1 on the side of the metal mold at two points 6 so that the metal shell member 1 and the metal shell 3 do not shift during molding. Fixed. Thereafter, the mold 4 was formed using self-hardening sand. The molten metal (cast steel) 5 was melted using a high frequency furnace and poured into the mold 4 at 1555 ° C. After cooling in the mold, sand removal and removal of the runner were carried out, and the metal 3 was knocked down with a hammer. As a result, the female screw member 1 having the unfused female screw 1a could be cast.

[0017]

Embodiment 2 FIG. 2 is a partial sectional front view showing a method for manufacturing a female screw portion according to a second embodiment of the present invention. An abutment 3 was provided on an end surface 2 of the female screw member 1 on the mold side. The female screw member 1 has the same size of the female screw 1a as that of the first embodiment of M2.
0, screw depth 30 mm, pilot hole depth 40 mm, and made of steel. The metal 3 is made of steel, has a cylindrical shape having a diameter of 40 mm and a length of 50 mm, and is provided with a vent hole 3c from the screw hole 1b of the female screw member 1 to the mold 4 at the center thereof to perform casting. The ventilation hole 3c was a drill hole having a diameter of 10 mm.

In the same manner as in the first embodiment, the female screw member 1 and the abutment 3 were spot-welded 6 and buried in the casting mold 4 for molding. Thereafter, the molten metal 5 was melted in a high frequency furnace and poured into the mold 4 at 1565 ° C. As a result, a good female screw 1a could be obtained, but slight adhesion of sand particles was observed on the surface of the female screw 1a. The attached sand particles are presumed to have entered through the air holes 3c during molding of the mold 4, but could be easily removed by tapping the female screw 1a.

[0019]

Third Embodiment FIG. 3 is a partial sectional front view showing a method for manufacturing a female screw portion according to a third embodiment of the present invention. An abutment 3 was provided on an end surface 2 of the female screw member 1 on the mold side. The female screw member 1 has a female screw 1a having a size of M2 similar to that of the second embodiment.
0, screw length 40 mm, pilot hole depth 50 mm, and made of steel. In addition, the metal 3 is formed into a cylindrical shape having a diameter of 40 mm and a length of 55 mm, and is provided with a vent hole 3c from the screw hole 1b of the female screw member 1 to the mold 4 at the center thereof. A piece of paper was provided as a gas permeable member 7 for preventing sand from entering the surface in contact with the sheet 4. The vent 3c has a diameter of 18 mm.
Drilled holes.

In the same manner as in the second embodiment, the female screw member 1 and the abutment 3 were formed by embedding in the mold 4 after spot welding 6. Thereafter, the molten metal 5 was melted in a high frequency furnace and poured into the mold 4 at 1560 ° C. As a result, a good female screw 1a could be obtained. It should be noted that no sand particles adhered to the surface of the female screw 1a as seen in the second embodiment.

[0021]

Fourth Embodiment FIG. 4 is a partial sectional front view showing a method for manufacturing a female screw portion according to a fourth embodiment of the present invention. An abutment 3 was provided on an end surface 2 of the female screw member 1 on the mold side. The female screw member 1 has a female screw 1a dimension of M24, a screw depth of 50 mm,
It is made of steel with a pilot hole depth of 60 mm. In addition, the metal 3 has a cylindrical shape with a basic dimension of 42 mm in diameter and 50 mm in length,
Further, a male screw 3d for screwing into the female screw 1a is M24,
It was provided with a length of 15 mm. Also, a casting method is provided in which a vent 3c from the screw hole 1b of the female screw member 1 to the mold 4 is provided at the center of the metal 3 and casting is performed on the surface where the vent 3c is in contact with the mold 4. A ceramic filter was provided as the member 7. This ceramic filter is a filter having fine holes which is usually used in a runner system to prevent foreign matter such as slag from being poured during pouring. In addition,
The ventilation hole 3c was a drill hole having a diameter of 14 mm.

The female screw 1a of the female screw member 1 was screwed with the male screw 3d of the metal 3 and assembled into the female screw 1a. Thereafter, the molten metal 5 was melted in a high frequency furnace and poured into the mold 4 at 1560 ° C. The result is the same as that of the fourth embodiment.
a could be obtained. In addition, since the ceramic filter, which is the gas permeable member 7, is a non-flammable substance, it can be repeatedly used and is economical.

[0023]

Embodiment 5 FIG. 5 is a sectional front view of a mold showing a fifth embodiment of the present invention and showing a method of manufacturing a cast part. First,
The shape of the cast part to be manufactured was machined by shaving out the disappearing model material, and the disappearing model 8 was manufactured. Cast parts are die materials for presses. Next, a hole for embedding the female screw member 1 at a desired position of the disappearing model 8 was opened with a knife. Female screw member 1
The metal 3 provided with the air holes 3c was integrally fixed by spot welding similarly to the third embodiment. Thereafter, the female screw member 1 was fitted into a desired position of the disappearing model 8, and the air hole 3c was closed using a piece of paper as the air permeable member 7. Subsequently, the lower casting flask 9 was covered, and self-hardening sand was charged to complete the lower mold 10. Further, the upper casting frame 11 was set on the lower casting frame 9, the feeder 12 and the sprue 13 were provided at desired positions, and self-hardening sand was charged to complete the upper mold 14.

After the self-hardening sand of the lower mold 10 and the upper mold 14 was sufficiently hardened, the molten metal (cast steel) melted in a 5-ton high-frequency furnace was placed in a stopper ladle and poured into the mold at 1560 ° C. After cooling in the mold, a series of operations from the mold dispersion to the riser and the cutting of the sprue were performed, and thereafter, the metal 3 was removed to obtain a desired mold material. As a result, it was possible to obtain a good cast part in which the female screw member 1 with no melting in the female screw portion was integrally cast. In addition, an eyebolt was screwed into the female screw of the casting part, lifted by a wire with a hook, and conveyed, but the handling was good.

[0025]

As described above, according to the present invention, it is possible to provide a good method of manufacturing a female screw portion and a cast part obtained by arranging an abutment on the end face of the female screw member on the mold side. It is easy to handle and safe to carry.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing a manufacturing method according to a first embodiment of the present invention in which a heat radiation surface area of a gold is larger than a heat absorption surface area of a female screw member.

FIG. 2 is a partial cross-sectional front view showing a manufacturing method of the second embodiment of the present invention in which a ventilation hole is provided in the gold.

FIG. 3 is a partial cross-sectional front view showing a manufacturing method according to a third embodiment of the present invention in which a ventilation hole is provided in an abutment and a permeable member is provided on an end surface on a mold side.

FIG. 4 is a partial cross-sectional front view showing a manufacturing method according to a fourth embodiment of the present invention in which a male screw is provided at one end of an abutment.

FIG. 5 is a sectional front view of a mold showing a method for manufacturing a cast part according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a method of screwing a male screw member to a female screw member and forming a female screw portion in the screwed state in the conventional example.

[Explanation of symbols]

 1: Female screw member 1a: Female screw 1b: Screw hole 2: End face 3: Metal 3a: Metal body 3b: Flange 3c: Vent 3d: Male screw 4: Mold 5: Molten metal 6: Welding 7: Air permeable member 8: Vanishing model 9: Lower casting frame 10: Lower casting mold 11: Upper casting flask 12: Feeder 13: Gate 14: Upper casting mold

Claims (7)

[Claims] In a method of casting a female screw member into a casting, a metal is provided on the female screw member, and a heat radiation surface area of the gold with a mold is larger than a heat absorption surface area of the female screw member and the molten metal. A method for producing a female screw portion, comprising: 2. A method of casting a female screw member into a casting, wherein a metal is provided on the female screw member, and the gold is provided with a vent hole from a screw hole of the female screw member to a mold. A method for manufacturing a female screw portion, comprising: 3. The female screw part according to claim 2, wherein a permeable member is provided on an end surface of the hole on the side where the air hole provided in the metal comes into contact with the mold or in the hole. Method. 4. The method for manufacturing a female screw according to claim 1, wherein the female screw and the metal are integrally welded and cast. 5. The female according to claim 1, wherein a male screw is provided at one end of the metal member, and the male screw is screwed into the female screw of the female screw member for casting. Manufacturing method of screw part. 6. The method according to claim 1, wherein the casting is performed using a disappearing model. 7. A casting part obtained by integrally casting a female screw member using the method for manufacturing a female screw part according to any one of claims 1 to 6.