JPH08174142A - Molding method of sand mold for casting - Google Patents

Abstract

PURPOSE: To prevent a chiller from falling during the pattern draw by attracting the chiller by a magnet provided on a molding pattern, and providing a fall- preventing tapered part having the reverse gradient to the draft on the chiller. CONSTITUTION: A molding flask 8 is loaded on a metallic pattern 1 for the upper die, and a chiller 7 is set to the metallic pattern 1 by fitting a hollow part of the chiller 7 to a pin 3. The chiller 7 is attracted by magnets 2, 2 provided on the die pattern 1, and positioned by the pin 3 in the horizontal direction. Then, a blow magazine is lowered from the top of the die pattern 1, and the molding sand 10 is charged into a molding flask 8. A squeeze head 11 is lowered in place of the blow magazine to squeeze the molding sand 10. The metallic pattern 1 is lowered to draw the pattern, and a cope is obtained. Because a fall-preventing tapered part 7b and an overhand 7c are provided on the chiller 7, the chiller 7 can be easily parted from the die pattern 1 for the cope without falling from the sand mold.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sand mold for casting, and more specifically, a chiller is provided inside for locally cooling a molten metal cast in a mold cavity or a solidified casting. The present invention relates to a sand mold molding method used for molding a sand mold for casting.

[0002]

2. Description of the Related Art When casting various metal products using a sand mold, the molten metal cast in the mold cavity is partially cooled to adjust the temperature gradient of the molten metal to an appropriate one, and to close it. As a method of preventing solidification defects such as cavities or locally hardening the part of the cast product that solidified in the mold cavity, set a metal chiller in the sand mold and melt it. Also, a method of increasing the cooling rate in the vicinity of the chiller of the cast product is widely known.

In order to set such a chiller in a sand mold, the sand mold is molded, and then the chiller is fitted into a predetermined position, or the chiller is attached in advance to a molding model such as a mold. The method of putting in and molding was adopted.

[0004]

However, the conventional chiller setting method described above has the following problems in the method of fitting the chiller after the sand mold is formed.

An extra gap is formed between the chiller and the sand mold, which causes casting and increases the number of finishing steps. Sand bite may occur due to lack of mold sand during chiller fitting. Skillful and careful work is required, and the number of man-hours for setting becomes enormous. During casting, the chiller may float due to the molten metal, causing misalignment.

Further, the method of mounting the chiller on the side of the model in advance has the following problems.

In molding, it is necessary to carefully position the chiller on the model, and similarly, the number of man-hours for setting becomes large. Since the chiller is only placed on the model and the mounting is unstable, sand trapping may occur between the chiller and the model. The mold sand may cause the chiller to float above the model surface. The chiller may shift. A gap is created due to the shift of the chiller, which causes casting and increases the number of finishing steps.

On the other hand, as a method for solving the above problems, Japanese Patent Laid-Open Nos. 52-148422 and 62-248534 disclose a method of fixing a chiller with a magnet installed in a mold model. Is proposed,
Due to the magnetic force, the chiller may be adsorbed and left on the model side, and may not move to the sand mold side during die cutting.

Further, in order to facilitate the separation of the chiller and the model, JP-A-56-74349 and JP-A-57-
No. 146930 and Japanese Patent Laid-Open No. 62-41439 use an electromagnet, and Japanese Laid-Open Patent No. 61-49746 has a spring attached to a non-magnetic push pin.
Each method of separating the chiller from the magnet by its elastic force is described, but each of them has a problem that the structure of the model must be complicated, and it is necessary to solve these problems. Was a problem in sand-making with a chiller.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional molding of a sand mold provided with a chiller, and the sand mold at the time of die cutting without using a molding model having a complicated structure. An object of the present invention is to provide a method for molding a sand mold for casting, which can effectively prevent the chiller from falling off.

[0011]

According to a first aspect of the present invention, there is provided a method for molding a sand mold for casting, in which a mold sand is charged with a chiller adsorbed by a magnet installed in a molding model to mold with a chiller. In the method for molding a sand mold, the chiller is provided with a taper portion for preventing slippage, which has a gradient opposite to the draft angle, preferably the gradient is 10 ° or less, and the sand mold for casting according to claim 3 of the present invention is provided. A molding method is a molding method of a casting sand mold in which mold sand is added in a state where a chiller is adsorbed by a magnet similarly installed in a molding model to mold with a chiller, and the chiller preferably has an overhang having a size of 10 mm or less. Is provided, and the construction of such a method for molding a sand mold for casting is a means for solving the above-mentioned conventional problems.

As an embodiment of the method for molding a sand mold for casting according to the present invention, the molding method according to claim 5 is characterized in that chiller positioning means is provided on the molding model.

[0013]

In the method for making a sand mold for casting according to the first aspect of the present invention, since the chiller is provided with the taper portion for preventing slippage having a slope opposite to the slope of the slope, the sand mold thus formed is Thus, the chiller is securely held, and the chiller that is attracted by the magnetic force during the die cutting does not remain on the model side. In the molding method according to claim 2 as an embodiment of the molding method of the sand mold for casting, since the inclination of the slip-out preventing taper portion provided on the chiller is 10 ° or less, the moldability of the sand mold is not impaired, It ensures that the chiller is held on the side of the sand mold.

In the method for manufacturing a sand mold for casting according to claim 3 of the present invention, since the overhang is provided on the chiller, the overhang acts in the same manner as the pull-out preventing taper. Similar to the molding method according to item 1, the chiller can be securely held in the sand mold, and the chiller will not fall out of the sand mold during the die cutting. Further, in the molding method according to claim 4 as an embodiment of the molding sand mold molding method, the size of the overhang provided on the chiller is 10 mm.
Because of the following, the chiller is reliably held on the sand mold side without impairing the moldability of the sand mold, as in the molding method according to claim 2.

Furthermore, in the molding method according to claim 5 as an embodiment of the molding method for the casting sand mold according to the present invention, since the chiller positioning means is provided on the molding model, the chiller can be easily aligned. Becomes Further, in the molding method according to the present invention, the chiller has a strong adhesive force, and even if the chiller and the chiller positioning means come into contact with each other during mold release, there is no risk of the chiller falling off. Therefore, the positioning dimensional accuracy of the chiller is further improved.

In the second and fourth aspects of the present invention, the angle of the slip-out preventing taper and the size of the overhang provided on the chiller are 10 ° or less and 10 respectively.
Limited to mm or less, these are 10 ° and 10 m
If it exceeds m, the mold sand cannot be firmly solidified during molding, and the chiller cannot be reliably held in the sand mold.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

FIGS. 1 to 8 are for explaining one embodiment of a method for making a sand mold for casting according to the present invention, and FIGS. 1 (a) and 1 (b) are for making the sand mold for casting. FIG. 2 is a plan view and a vertical sectional view showing the shape of the upper mold die model used in the method, and FIG. 2 is a plan view showing the shape of the lower mold die model used in the molding method.

In the figure, an upper die model (molding model) 1 has a gate pattern portion 1a for forming a gate into which molten metal is poured during casting and a gate pattern portion 1b for forming a gate. A product pattern portion 1c for forming a mold cavity corresponding to the shape of the cast product is provided, and a magnet 2 for adsorbing a chiller 7 described later is provided at a predetermined portion of the product pattern portion 1c where local cooling is desired. , 2 and a pin 3 as a positioning means having a truncated cone shape are installed.

The lower mold model (molding model) shown in FIG.
4 includes a product pattern portion 4a for forming a mold cavity that matches the shape of the cast product, and a predetermined portion of the product pattern portion 4a has the same shape as the upper die mold model 1,
The magnets 5 and 5 for attracting the chiller 7 and the pin 6 as a positioning means having a truncated cone shape are installed.

FIG. 3 shows the shape of the chiller used in this example to locally cool the molten metal filled in the mold and the cast product solidified in the mold.
The chiller 7 shown in the figure is made of cast iron in this embodiment, and has a truncated cone shape having a hollow portion 7a at the center,
The side surface portion is an inclined surface to form a slip-out preventing taper portion 7b, and an overhang 7c projecting like a flange in the outer peripheral direction is formed at the lower end portion in the drawing.

Next, the procedure for molding a sand mold for casting using the above-structured upper and lower mold models 1, 4, pins 3, 6 and chiller 7 will be described with reference to FIGS. 4 to 9. explain.

First, as shown in FIG. 4, the casting frame 8 is placed on the upper die model 1, and the hollow portion 7a of the chiller 7 is fitted to the pin 3 provided on the die model 1. Thus, the chiller 7 is set on the mold model 1. At this time, the chiller 7, as shown in FIG.
Since it is adsorbed by 2 and is positioned horizontally by the pin 3, it can be easily and surely set on the mold model 1. Further, in the present invention, since the close contact between the chiller and the mold sand is good, it is not necessary to take a large clearance between the pin 3 and the chiller 7, and therefore the positioning of the chiller 7 is guaranteed with high accuracy. .

Next, as shown in FIG. 6, the blow magazine 9 is lowered from above the mold model 1 and the mold sand 1 is placed in the molding frame 8.
Input 0.

Subsequently, the blow magazine 9 is replaced with the one shown in FIG.
As shown in Figure 1, lower the squeeze head 11 to remove sand 1
Stick to 0. In these steps, the chiller 7 is attracted to the mold model 1 by the magnetic force of the magnets 2 and 2 and is reliably set, so that sand is caught between the chiller 7 and the mold model 1 and the mold sand 10 causes the chiller 7 to mold. There is no floating up from the die model 1 and displacement of the chiller 7 and the like, so that the occurrence of casting defects based on these is prevented.

Then, as shown in FIG. 8, the die 1 is lowered to perform die cutting, and an upper die (sand mold for casting) 12 is obtained. At this time, since the chiller 7 is provided with the slip-out preventing taper portion 7b and the overhang 7c as described above, the chiller 7 is integrated with the sand mold 12 without falling off from the sand mold 12 and the upper mold die. Easily released from the model 1.

FIG. 9 shows the upper mold 12 thus obtained.
And a lower mold (sand mold for casting) 13 molded by the same process using the lower mold model 4, the pin 6 and the chiller 7.
Shows a state in which and are combined, and the product cast by using such an upper mold 12 and a lower mold 13 has a higher cooling rate in the vicinity of the chiller 7, so that the part is compared with other parts. Can be locally cured.

[0028]

As described above, according to the first aspect of the present invention.
In the method for making a sand mold for casting according to claim 3, since the chiller is provided with a taper portion for preventing removal having an inclination opposite to the draft angle or an overhang, the chiller is securely held in the sand die. You can
The excellent effect that the chiller can be effectively prevented from falling off during die cutting is provided. Further, in the molding method according to claim 2 and claim 4 as an embodiment of the method for molding a sand mold for casting according to claim 1 and claim 3 of the present invention, the slope and the overrun of the taper portion for preventing slippage provided in the chiller. Since the size of the hang is 10 ° or less and 10 mm or less, the moldability of the sand mold is not impaired, and the adhesion between the chiller and the sand mold can be improved.

Furthermore, in the molding method according to claim 5 as an embodiment of the molding method of the casting sand mold according to the present invention, since the chiller positioning means is provided in the molding model, the chiller can be easily aligned. At the same time, there is no risk of the chiller falling off, so there is no need to take a clearance between the chiller and the chiller positioning means.
The excellent effect that the positioning dimensional accuracy of the chiller can be further improved is provided.

[Brief description of drawings]

1A and 1B are a plan view and a vertical cross-sectional view showing the shape of an upper die mold model used in a method for making a sand mold for casting according to an embodiment of the present invention.

FIG. 2 is a plan view showing the shape of a lower die mold model used in a method for producing a sand mold for casting according to an embodiment of the present invention.

FIG. 3 is a perspective view showing the shape of a chiller used in a method for making a sand mold for casting according to an embodiment of the present invention.

FIG. 4 is a process chart showing a procedure of a method for molding a sand mold for casting according to an embodiment of the present invention, and an explanatory view showing a situation in which a chiller is set on a mold model for an upper mold.

FIG. 5 is likewise a process drawing, which is an explanatory view showing a state in which a chiller is set on a mold model.

FIG. 6 is also a process drawing, which is an explanatory view showing a situation in which mold sand is put into a molding frame placed on a mold model.

FIG. 7 is likewise a process drawing, which is an explanatory view showing a situation in which mold sand is solidified by a squeeze head.

FIG. 8 is likewise a process drawing, which is a process drawing showing a state of die cutting from a sand mold.

FIG. 9 is likewise a process drawing, which is an explanatory view showing a state of being matched with a similarly manufactured lower mold.

[Explanation of symbols]

 1 Mold Model for Upper Mold (Model for Molding) 2 Magnet 3,6 Pin (Chiller Positioning Means) 4 Mold Model for Lower Mold (Model for Molding) 7 Chiller 7b Detaching Prevention Tapered Part 7c Overhang 12 Upper Mold ( Sand mold for casting) 13 Lower mold (sand mold for casting)

Claims (5)

[Claims] 1. A method for molding a casting sand mold in which mold sand is introduced in a state where a chiller is adsorbed by a magnet installed in a molding model to mold with a chiller, in which the chiller has a slope opposite to the slope. A method for manufacturing a sand mold for casting, characterized by providing a taper portion for use. 2. The method for molding a sand mold for casting according to claim 1, wherein the slope of the slip-out preventing taper portion provided on the chiller is 10 ° or less. 3. A method of molding a sand mold for casting, in which mold sand is introduced in a state where a chiller is attracted by a magnet installed in a molding model to mold together with the chiller, wherein an overhang is provided on the chiller. Sand mold making method. 4. The method for producing a sand mold for casting according to claim 3, wherein the size of the overhang provided on the chiller is 10 mm or less. 5. The method for molding a sand mold for casting according to claim 1, wherein the molding model is provided with chiller positioning means.