JP2009248180A - Casting die provided with cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the technique which can effectively perform the cooling of a casting die while preventing the damage of the casting die. <P>SOLUTION: A cavity 6 into which molten metal is introduced is formed at the upper face 4 of a die 2. A refrigerant passage 16 elongating from the lower face 18 toward the upper face 4 to a termination 14 and into which a cooling medium is introduced is formed at the inside of the die 2. The first taper part 12 and the second taper part 10 are formed at the terminal part 8 of the refrigerant passage 16, and the second taper part 10 is an acute angle taper part along a conical face whose vertical angle is <90 degrees. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a casting mold having a cooling structure.

  In casting using a casting mold such as a mold, in order to maintain a constant temperature of the casting mold in the casting process, a coolant channel is provided inside the casting mold, and a cooling medium such as water or oil is circulated there. Technology is known. For example, in the technique described in Patent Document 1, a cooling passage is formed inside a casting mold along a cavity (molding surface) of the casting mold, and cooling water is circulated therein. By forming the coolant channel inside the casting mold, it is possible to remove the heat transmitted from the molten metal in the cavity and prevent the temperature of the casting mold from rising excessively.

Japanese Patent Laid-Open No. 11-170024

The temperature of the casting mold varies greatly as the casting process is repeated. In particular, in the vicinity of the cavity in contact with the molten metal, the amplitude of the temperature fluctuation becomes very large. For this reason, it is preferable to form the coolant channel so as to be close to the cavity. On the other hand, when the coolant channel is formed up to the vicinity of the cavity, the thickness of the casting mold is reduced, and therefore, the casting mold is deformed or cracked due to thermal fatigue.
In view of the above problems, the present invention provides a technique capable of effectively cooling a casting mold while preventing damage to the casting mold.

  The casting mold according to the present invention includes a cavity into which a molten metal is introduced and a refrigerant flow path into which a cooling medium is introduced. The refrigerant flow path extends in a direction approaching the cavity from the surface of the casting mold to the end located inside the casting mold. A taper portion whose diameter decreases toward the end is formed at the end portion (portion extending from the end to a certain length) of the refrigerant flow path. And at least one part of the taper part is an acute angle taper part along the conical surface whose apex angle is less than 90 degree | times, It is characterized by the above-mentioned.

In the above description, a conical surface having an apex angle of 90 degrees or less can also be expressed as a conical surface having an angle formed by the bus and the central axis of 45 degrees or less.
Further, that the refrigerant flow path extends in a direction approaching the cavity means that the refrigerant flow path extends in a direction approaching the cavity as a whole, and the entire refrigerant flow path is straight toward the cavity. However, it is not limited to those that are stretched. Further, the fact that the refrigerant flow path extends in the direction of forming the cavity is not limited to a structure in which the cavity is positioned on the extended line of the refrigerant flow path.

When a taper portion whose diameter decreases toward the terminal end is formed in the terminal portion of the refrigerant flow path, the diameter reduction start position at which the diameter starts to decrease (the taper portion located on the side opposite to the terminal end of the refrigerant flow path) At the end, where the inner peripheral surface of the refrigerant flow path bends), the casting mold is likely to crack. Furthermore, if the diameter reduction start position is formed near the cavity, the thickness between the diameter reduction start position and the cavity becomes thin, and the casting mold is deformed or cracked due to thermal fatigue. It becomes easy to do.
On the other hand, in the casting mold of the present invention, the end portion of the refrigerant flow path is provided with an acute angle taper portion along a conical surface having an apex angle of less than 90 degrees. A conical surface having an apex angle of less than 90 degrees has a height that is larger than the radius of the bottom surface and has a shape that extends sharply along the central axis. Therefore, by providing such an acute angle taper portion along the conical surface, the distance from the end of the refrigerant flow path to the diameter reduction start position can be increased. In this case, even when the refrigerant flow path is extended to the vicinity of the cavity and the end of the refrigerant flow path is close to the cavity, the diameter reduction start position of the refrigerant flow path can be relatively separated from the cavity. It is possible to ensure a sufficient thickness between the diameter reduction start position of the refrigerant flow path and the cavity, and it is possible to prevent the casting mold from being deformed or cracked. According to the present invention, the reduction start position of the diameter of the tapered portion can be separated from the terminal end. An appropriate thickness can be ensured between the refrigerant flow path and the cavity according to the required cooling efficiency.

  In the above casting mold, the cavity is formed on the upper surface of the casting mold, the refrigerant flow path extends from the lower surface side of the casting mold toward the upper surface, and the end of the refrigerant flow path is above the lowermost part of the cavity. The lower end of the acute tapered surface of the coolant channel may be located below the lowermost part of the cavity.

  In the casting mold having the above structure, the end of the refrigerant flow path is located above the lowest part of the cavity. For example, the coolant channel can be formed at a position adjacent to the side of the cavity, and the casting mold can be efficiently cooled. In the above casting mold, the lower end of the acute taper surface is located below the lowest part of the cavity. That is, it is possible to separate the portion that is likely to be damaged such as cracks in the coolant channel from the surface of the cavity, and to prevent the portion that is vulnerable to thermal fatigue from being formed in the casting mold. According to the present invention, it is possible to efficiently prevent the casting mold from being damaged.

  In the casting mold described above, the acute taper portion may be formed in a range farthest from the terminal end in the taper portion.

  By having said structure, the lower end part of an acute angle taper part and the surface of a cavity can be spaced apart. According to the present invention, damage to the casting mold can be prevented.

  According to the present invention, an appropriate thickness can be ensured between the refrigerant flow path and the cavity. It is possible to prevent local stress from being generated in the thick portion between the refrigerant flow path and the cavity. According to the present invention, it is possible to effectively cool the casting mold while preventing damage to the casting mold.

The main features of the embodiments described below are listed.
(Characteristic 1) The end of the refrigerant flow path extends toward the upper surface other than the area where the cavity is formed.
(Characteristic 2) The thinnest portion between the refrigerant flow path and the cavity is formed between the acute angle taper portion and the cavity.
(Characteristic 3) The thinnest part between the refrigerant flow path and the cavity is between the position where the diameter of the acute taper portion starts to decrease and the position where the diameter reduction ends, that is, the intermediate position of the acute angle taper portion. Formed.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a casting mold (die) of the present embodiment. The mold 2 includes an upper surface 4 and a lower surface 18. A cavity 6 into which a molten metal (not shown) is introduced is formed on the upper surface 4. A plurality of cavities including cavities 6 may be formed on the upper surface 4. Inside the mold 2, a coolant channel 16 into which a cooling medium (not shown) is introduced is formed. A plurality of refrigerant flow paths may be formed in the mold 2. The coolant channel 16 extends from the lower surface 18 toward the upper surface 4 to the terminal end 14 located inside the mold 2. In other words, the refrigerant flow path 16 extends in a direction approaching the cavity 6 from the lower surface 18 side. A pipe 22 for supplying a cooling medium is disposed inside the refrigerant flow path 16. The pipe 22 includes an opening 22 a on one end side disposed in the refrigerant flow path 16. The other end side of the pipe 22 is connected to a supply source (not shown) of water that is a cooling medium of the present embodiment. The pipe 22 supplies water into the refrigerant flow path 16 from the opening 22a. The supplied water circulates in the refrigerant flow path 16 and removes heat transmitted from the molten metal introduced into the cavity 6.

A first tapered portion 12 and a second tapered portion 10 are formed at the end portion 8 of the refrigerant flow path 16. In the first taper portion 12 and the second taper portion 10, the diameter of the refrigerant flow path 16 is continuously reduced toward the terminal end 14.
The first taper portion 12 is formed between the terminal end 14 and the second taper portion 10, and has a taper shape whose diameter rapidly decreases toward the terminal end 14. The second taper portion 10 is formed on the lower side of the first taper portion 12 and has a taper shape whose diameter gradually decreases toward the terminal end 14 as compared with the first taper portion 12. Each of the first taper portion 12 and the second taper portion 10 has a shape along the conical surface. In other words, the terminal portion 8 is formed with a tapered portion including the first tapered portion 12 and the second tapered portion 10.

  The diameter of the second taper portion 10 starts to decrease from the lower end 20 on the side opposite to the terminal end 14 side (hereinafter, the position of the lower end 20 may also be referred to as a radial contraction start position of the second taper portion 10). The 2nd taper part 10 is an acute angle taper part along the conical surface whose apex angle (theta) (refer FIG. 2) is less than 90 degree | times. The second taper portion 10 is formed in a range farthest from the terminal end 14 among the taper portions formed in the terminal end portion 8 described above. As shown in FIG. 1, the refrigerant flow path 16 below (on the lower surface 18 side) the diameter reduction start position 20 is formed in a cylindrical surface shape having a constant cross-sectional shape along the axial direction. For this reason, the inner peripheral surface of the refrigerant flow path 16 is bent radially inward at the diameter reduction start position 20. The bending angle is larger than 135 degrees, and it bends relatively gently.

  FIG. 2 is a diagram showing the positional relationship between the cavity 6 and the refrigerant flow path 16. In the vertical direction of the mold 2 indicated by arrows in FIG. 2, the end 14 (position indicated by A) of the refrigerant flow path 16 is located above the lowermost portion 24 (position indicated by B) of the cavity 6. . Further, the lower end 20 (position indicated by C) of the second tapered portion 10 of the refrigerant flow path 16 is located below the lowermost portion 24 of the cavity 6.

  When the high temperature molten metal is introduced into the cavity 6, the mold 2 is expanded by the heat transferred from the molten metal. The expansion of the mold 2 appears particularly strongly in the vertical direction shown in FIG. When the mold 2 expands in the vertical direction, tensile stress is generated in the mold 2 in the vertical direction. At this time, the tensile stress is likely to concentrate on the thinnest portion between the cavity 6 and the refrigerant flow path 16. Therefore, for example, if the bent portion of the refrigerant flow path 16 (in this embodiment, the diameter reduction start position 20) is formed close to the thin portion, the thin portion is likely to be deformed or cracked. On the other hand, in the mold 2 of the present embodiment, the diameter reduction / reduction start position 20 of the coolant channel 16 is located below the lowermost part 24 of the cavity 6, and the diameter reduction / reduction start position 20 is relatively separated from the cavity 6. is doing. The diameter reduction / reduction start position 20 of the refrigerant flow path 16 does not coincide with the thin portion between the cavity 6 and the refrigerant flow path 16, and stress concentration does not occur excessively. The casting mold can be effectively cooled while preventing the casting mold from being damaged.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

It is sectional drawing showing schematic structure of a metal mold | die. It is sectional drawing showing the positional relationship of a cavity and a refrigerant flow path.

Explanation of symbols

2: Mold 4: Upper surface 6: Cavity 8: End portion 10: Second tapered portion 12: First tapered portion 14: End 16: Refrigerant flow path 18: Lower surface 20: Lower end 22: Pipe 22a: Opening 24: Lowermost portion

Claims (3)

A casting mold,
A cavity into which the molten metal is introduced,
A refrigerant flow path through which a cooling medium is introduced;
The refrigerant flow path extends in a direction approaching the cavity from the surface of the casting mold to the end located inside the casting mold,
The end portion of the coolant channel is formed with a tapered portion whose diameter decreases toward the end,
At least a part of the taper portion is an acute angle taper portion along a conical surface having an apex angle of less than 90 degrees. The cavity is formed on the upper surface of the casting mold,
The refrigerant flow path extends from the lower surface side of the casting mold toward the upper surface,
The end of the refrigerant flow path is located above the lowest part of the cavity,
The casting mold according to claim 1, wherein a lower end of an acute taper surface of the refrigerant flow path is positioned below a lowermost part of the cavity.   The casting mold according to claim 2, wherein the acute angle taper portion is formed in a range farthest from the terminal end in the taper portion.

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