JP5268965B2 - Mold cooling structure and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform uniform cooling in the periphery of a die cooling hole. <P>SOLUTION: The die cooling structure 1 includes: an inner cylinder 4 that is arranged in a cooling hole 3 formed in a die 2; a plurality of heat transfer grains (metallic balls 8) that are evenly arranged in the entire gap 6 formed between the outer surface of the tip end 41 of the inner cylinder 4 and the inner surface of the cooling hole 3 and that are in contact with both the surfaces; and a joint member 5 that is connected to the inner cylinder 4 and that supplies a coolant into the inner cylinder 4. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a mold cooling structure for cooling a mold with a refrigerant.

  In the casting mold, in order to make the mold surface temperature uniform, a cooling hole extending from the back of the mold to the vicinity of the cavity surface is formed, and cooling (for example, water) is supplied to the cooling hole. Some have adopted a structure.

  In such a cooling configuration, since the mold thickness near the bottom of the cooling hole is reduced to increase the cooling capacity, cracks are likely to enter the mold from the portion. When a crack enters the mold, the refrigerant enters the cavity through the crack and evaporates, which may cause a product defect (gas defect).

  Therefore, in the mold cooling structure disclosed in Patent Document 1, when a metal inner cylinder is press-fitted into the cooling hole and a coolant is supplied to the inside of the inner cylinder, the mold is cracked. Even so, the refrigerant is prevented from entering the cavity.

JP-A-9-29416

  However, in the cooling structure described in Patent Document 1, it is difficult to closely contact the outer surface of the inner cylinder and the inner surface of the cooling hole. Cooling is not sufficiently performed, causing a local rise in the mold surface temperature.

  The present invention has been made in view of such technical problems, and it is an object of the present invention to uniformly cool the periphery of a cooling hole of a mold.

  According to an aspect of the present invention, there is provided a mold cooling structure, an inner cylinder disposed in a cooling hole formed in the mold, an outer surface of a tip portion of the inner cylinder, and an inner part of the cooling hole A plurality of heat transfer particles that are uniformly disposed in the entire gap formed between the surfaces and are in contact with the two surfaces, and a joint that is connected to the inner cylinder and supplies the refrigerant into the inner cylinder. And a mold cooling structure including the member.

  Further, according to another aspect of the present invention, there is provided a method for manufacturing a mold cooling structure, wherein a plurality of heat transfer particles are uniformly attached to the entire outer surface of the tip of the inner cylinder, A step of inserting the inner cylinder body to which a plurality of heat transfer particles are attached into a cooling hole formed in a mold and disposing the inner cylinder body in the cooling hole, and a joint for supplying a refrigerant into the inner cylinder body And a step of connecting a member to the inner cylinder. A method for manufacturing a mold cooling structure is provided.

  According to the above aspect, the plurality of heat transfer granules are uniformly arranged in the entire gap formed between the outer surface of the tip portion of the inner cylinder and the inner surface of the cooling hole. Accordingly, the heat is uniformly transferred from the mold to the inner cylinder, and further to the refrigerant flowing through the inner cylinder, and the temperature of the mold can be prevented from rising locally.

It is a block diagram of the metal mold | die cooling structure which concerns on embodiment of this invention. It is the flowchart which showed the manufacturing process of the metal mold | die cooling structure which concerns on embodiment of this invention. It is a figure for demonstrating the manufacturing process of a metal mold | die cooling structure. It is a figure for demonstrating the manufacturing process of a metal mold | die cooling structure. It is an enlarged view of the A section of FIG. It is a figure for demonstrating the manufacturing process of a metal mold | die cooling structure. It is an enlarged view of the B section of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a mold cooling structure 1 according to an embodiment of the present invention, and a mold 2 is a die-casting mold used in aluminum die casting, for example.

  The mold cooling structure 1 includes a cooling hole 3 formed in the mold 2, an inner cylinder 4 disposed in the cooling hole 3, and a continuous refrigerant in the inner cylinder 4 connected to the inner cylinder 4. And a joint member 5 to be supplied. In this example, water is used as the refrigerant, but oil can also be used as the refrigerant.

  Explaining each configuration, the cooling hole 3 is a hole extending from the back surface of the mold 2 toward the cavity surface (surface exposed to the cavity defined by the mold 2) to the vicinity of the cavity surface. The bottom of the cooling hole 3 has a hemispherical shape, and the open end side is a diameter-expanded portion 31 having a larger shape than other portions.

  The inner cylinder 4 is connected to a tip part 41 having a hemispherical shell shape and a barrel part 42 having a same inner diameter as the tip part 41 and a larger outer diameter than the tip part 41. A base portion 43 having an outer diameter larger than that of the body portion 42 is provided. A stepped portion 44 (FIG. 5) is formed in the circumferential direction between the distal end portion 41 and the body portion 42 due to the difference in the outer diameters thereof, whereby the outer surface of the distal end portion 41 of the inner cylindrical body 4 and the cooling hole are formed. A gap 6 corresponding to the height of the stepped portion 44 is formed between the inner surfaces of the three. The outer diameter of the base portion 43 of the inner cylinder 4 is substantially equal to the inner diameter of the enlarged diameter portion 31 of the cooling hole 3, and a female screw into which the connecting portion 54 of the joint member 5 is screwed onto the inner surface of the inner cylinder 4. Part is formed. As the material of the inner cylinder 4, a metal excellent in heat transfer and rust prevention, for example, stainless steel or copper alloy is used.

  In the gap 6 formed between the outer surface of the distal end portion 41 of the inner cylinder 4 and the inner surface of the cooling hole 3, a plurality of metal balls 8 as heat transfer granules are uniformly disposed throughout. “Uniform” means that the distribution of the metal balls 8 in the gap 6 is not biased as the entire gap 6, and the metal balls 8 are required to be arranged at equal intervals or without any gap. Not what you want. The metal ball 8 has a spherical shape whose diameter is the same as or slightly smaller than the gap 6, but is disposed in the gap 6 in a state of being slightly plastically deformed in the normal direction of the outer surface of the tip 41 and the inner surface of the cooling hole 3. Thus, the metal ball 8 and both surfaces are in surface contact with each other (FIG. 7).

  The diameter of the metal ball 8 before plastic deformation is, for example, 1 mm, and the crushing allowance due to plastic deformation is about 0.1 to 0.2 mm. As a material of the metal ball 8, a metal that is excellent in heat transfer and easily plastically deformed, for example, copper is used.

  Moreover, in order to improve heat transferability between the mold 2 and the inner cylindrical body, thermo grease 9 is sealed in the minute gaps formed between the metal balls 8 (see FIG. 7). . The thermo grease 9 is also called heat transfer grease and is a grease in which metal powder such as copper and aluminum is mixed.

  The joint member 5 includes an inlet connector 52 and an outlet connector 53 that extend from the joint body 51, a connecting portion 54 that extends downward from the lower side of the joint body 51, and has an external thread formed on the outer periphery, and an inner cylindrical body from the lower surface of the connecting portion 54 4 is provided with a water passage 55 extending toward the inside, and a discharge port 56 opened on the lower surface of the connecting portion 54. The inlet connector 52 and the water flow pipe 55, and the outlet connector 53 and the discharge port 56 are connected by flow paths (not shown) formed in the joint body 51, respectively.

  The water flowing into the joint body 51 from the inlet connector 52 is supplied into the inner cylinder body 4 through the flow path in the joint body 51 and the water pipe 55, and the inner cylinder body 4, the metal ball 8 and the thermo grease 9 are supplied. The heat | fever of the metal mold | die 2 is absorbed through. Water whose temperature has been increased due to cooling of the mold 2 passes through a flow path formed between the inner cylinder 4 and the water flow pipe 55, a discharge port 56, and a flow path in the joint main body 51, and then the outlet connector 53. Discharged from the outside.

  Next, a method for manufacturing the mold cooling structure 1 will be described.

  The mold cooling structure 1 is manufactured through steps S1 to S6 shown in FIG. Hereinafter, each step will be described.

  In S <b> 1, the worker prepares the inner cylinder 4. FIG. 3A shows the prepared inner cylinder 4.

  In S <b> 2, the operator immerses the tip 41 in a container in which the tip 41 of the inner cylinder 4 is filled with thermogrease, and applies the thermogrease 9 to the entire outer surface of the tip 41. FIG. 3B shows the inner cylindrical body 4 in a state where the thermogrease 9 is applied to the distal end portion 41.

  In S <b> 3, the operator inserts the tip 41 of the inner cylinder 4 into a container filled with many metal balls 8, and uses the viscosity of the thermogrease 9 to apply the metal balls 8 to the entire outer surface of the tip 41. To adhere uniformly. FIG. 3C shows the inner cylindrical body 4 in a state where the metal ball 8 is attached to the distal end portion 41.

  In S4, the operator inserts the inner cylindrical body 4 with the metal ball 8 attached to the tip 41 into the cooling hole 3 of the mold 2 (FIG. 4). When the metal ball 8 comes into contact with the inner wall of the cooling hole 3 at the time of insertion, a friction force acting in the direction opposite to the insertion direction acts on the metal ball 8, but the step portion 44 formed on the outer surface of the inner cylinder 4 (see FIG. 5) restricts the movement of the metal ball 8 toward the base 43 side, so that the metal ball 8 is fed together with the inner cylinder 4 to the bottom of the cooling hole 3. As a result, the metal balls 8 are uniformly disposed in the gap 6 formed between the outer surface of the tip 41 of the inner cylinder 4 and the inner surface of the cooling hole 3 without any bias.

  In S5, the operator inserts the jig 10 through the opening of the inner cylinder 4 and strikes the jig 10 with a hammer to lightly press the inner cylinder 4 into the cooling hole 3 (FIG. 6). The jig 10 has a spherical body 10a whose diameter is slightly larger than the inner diameter of the inner cylinder 4 at the tip, and when this is pushed into the inner cylinder 4, the diameter of the inner cylinder 4 is increased. The entire inner cylinder 4 is pushed toward the bottom of the cooling hole 3.

  Thereby, in the front-end | tip part 41 of the inner cylinder 4, the clearance gap 6 formed between the outer surface of the front-end | tip part 41 and the inner surface of the cooling hole 3 becomes narrow, and the metal ball 8 arrange | positioned in this clearance gap 6 becomes Both surfaces are plastically deformed and crushed, and are in surface contact with both surfaces. And the thermogrease 9 adhering to the outer surface of the front-end | tip part 41 with the metal ball 8 is enclosed by the micro clearance gap formed between the metal balls 8 (FIG. 7). Since the metal balls 8 are arranged uniformly over the entire gap 6, the thermo grease 9 enclosed between them is also arranged uniformly over the entire gap 6. Further, in the body portion 42 of the inner cylinder body 4, there is almost no gap between the outer surface of the body portion 42 and the inner surface of the cooling hole 3, and the inner cylinder body 4 is stably disposed and held in the cooling hole 3. Is done.

  In S <b> 6, the worker screws the connecting portion 54 of the joint member 5 into the base portion 43 of the inner cylinder 4, thereby obtaining the mold cooling structure 1 shown in FIG. 1.

  In this example, the operator performs all the steps, but some or all of the steps can be performed by a machine.

  Next, the effect by having employ | adopted the said mold cooling structure 1 is demonstrated.

  According to the mold cooling structure 1, the metal balls 8 as a plurality of heat transfer granules are formed in the entire gap 6 formed between the outer surface of the tip 41 of the inner cylinder 4 and the inner surface of the cooling hole 3. Are arranged uniformly. Thereby, the heat transfer from the mold 2 to the inner cylinder 4 and further to the water flowing in the inner cylinder 4 is uniformly performed through the metal balls 8, and the temperature of the mold 2 is locally increased. (Effects corresponding to claims 1 and 6).

  Even when the inner cylinder 4 needs to be removed for maintenance of the mold 2, for example, for repairing a crack, the inner cylinder 4 is inserted into the cooling hole 3 (light press-fitting in the above embodiment). Therefore, it can be easily removed simply by pulling the inner cylinder 4.

  Further, since the metal ball 8 is in surface contact with the outer surface of the tip portion 41 of the inner cylinder 4 and the inner surface of the cooling hole 3, heat transfer between the mold 2 and the metal ball 8, the metal ball 8 and the inner cylinder. Heat transfer between the bodies 4 is performed well, and excellent heat transfer properties can be realized between the mold 2 and the inner cylinder 4 (effect corresponding to claim 2).

  Further, thermo grease 9 is enclosed in a minute gap formed between the metal balls 8. Thereby, since heat transfer is performed via the thermogrease 9 even in a portion where the metal ball 8 does not contact, the heat transfer performance can be further enhanced (effect corresponding to claims 3 and 4). Thermoglyce 9 is suitable as the fluid to be sealed, but is not limited to this, and any fluid that has a heat transfer coefficient higher than that of air may be used.

  Further, a step portion 44 that restricts the movement of the metal ball 8 toward the base portion 43 is formed on the outer surface of the inner cylindrical body 4. This prevents the metal ball 8 from being biased or dropped off when the inner cylinder 4 is inserted into the cooling hole 3, and is formed between the outer surface of the tip 41 of the inner cylinder 4 and the inner surface of the cooling hole 3. The metal balls 8 can be uniformly arranged in the entire gap 6 (effect corresponding to claim 5).

  The mold cooling structure 1 is manufactured by uniformly attaching the metal ball 8 to the tip 41 of the inner cylinder 4 and inserting the metal ball 8 into the cooling hole 3. Thereby, it is possible to easily manufacture the mold cooling structure 1 (effect corresponding to claim 6).

  Also, the inner cylinder 4 with the metal ball 8 attached is inserted, and the gap 6 formed between the outer surface of the tip 41 of the inner cylinder 4 and the inner surface of the cooling hole 3 is reduced to reduce the metal ball 8. Plastically deform. Thereby, the surface contact between the metal ball 8 and the outer surface of the tip portion 41 of the inner cylinder 4 and the inner surface of the cooling hole 3 can be easily realized (effect corresponding to claim 7).

  The embodiment of the present invention has been described above. However, the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, the present invention is not limited to a mold used for aluminum die casting, but can be applied to all molds that require cooling.

  Moreover, although the metal balls 8 were used as the heat transfer granules disposed in the gap 6 formed between the outer surface of the tip portion 41 of the inner cylinder 4 and the inner surface of the cooling hole 3, The shape is not limited to a spherical shape, and may be a convex lens shape, an eyebrows shape, a hemispherical shape, or the like.

  In addition, as a method of attaching the metal ball 8 to the distal end portion 41 of the inner cylinder 4, the method using the viscosity of the thermogrease 9 has been described. However, the metal ball 8 may be attached using an adhesive, a magnet, or the like.

DESCRIPTION OF SYMBOLS 1 Mold cooling structure 2 Mold 3 Cooling hole 4 Inner cylinder 41 Tip part 43 Base part 44 Step part 5 Joint member 6 Crevice 8 Metal ball (heat-transfer granule)
9 Thermo grease

Claims (7)

Mold cooling structure,
An inner cylinder disposed in a cooling hole formed in the mold,
A plurality of heat transfer particles that are uniformly disposed in the entire gap formed between the outer surface of the tip of the inner cylinder and the inner surface of the cooling hole, and that are in contact with both surfaces;
A joint member connected to the inner cylinder and supplying a refrigerant into the inner cylinder;
A mold cooling structure characterized by comprising: The mold cooling structure according to claim 1,
The plurality of heat transfer particles are in surface contact with both surfaces;
A mold cooling structure characterized by that. The mold cooling structure according to claim 1 or 2,
A fluid having a higher heat transfer coefficient than air is enclosed in a gap formed between the plurality of heat transfer granules,
A mold cooling structure characterized by that. The mold cooling structure according to claim 3,
The fluid is a thermoglyce;
A mold cooling structure characterized by that. The mold cooling structure according to any one of claims 1 to 4,
A step portion for restricting movement of the plurality of heat transfer particles to the base side of the inner cylinder is formed on the outer surface of the inner cylinder.
A mold cooling structure characterized by that. A method of manufacturing a mold cooling structure,
A step of uniformly attaching a plurality of heat transfer particles to the entire outer surface of the tip of the inner cylinder,
Inserting the inner cylinder to which the plurality of heat transfer particles are attached into a cooling hole formed in a mold, and disposing the inner cylinder in the cooling hole;
Connecting a joint member for supplying a refrigerant into the inner cylinder to the inner cylinder;
The manufacturing method of the metal mold | die cooling structure characterized by including this. It is a manufacturing method of the metallic mold cooling structure according to claim 6,
The inner cylinder is plastically deformed to reduce the gap formed between the outer surface of the tip of the inner cylinder and the inner surface of the cooling hole, thereby plastically deforming the plurality of heat transfer granules. The process of
The manufacturing method of the metal mold | die cooling structure characterized by including this.

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