JP5423211B2 - Mold cooling system - Google Patents

Description

  The present invention relates to a mold cooling apparatus that cools a mold by causing a coolant to flow in a cooling hole formed inside the mold.

  As a conventional mold cooling method, a technique is known in which cooling water is applied to a mold cavity surface after taking out a product from a mold and cooled from the outside of the mold (see, for example, Patent Document 1).

  In addition, a cooling hole is provided in the mold, and a sleeve that forms a heat insulation mechanism is arranged so that the cooling water does not directly touch the inside of the cooling hole and other than the tip portion. A technique that prevents cracking of a material and enables local cooling is disclosed (for example, see Patent Document 2).

JP 2003-205346 A Japanese Patent Laid-Open No. 2000-5845

  However, in Patent Document 1, when cooling water is sprayed on the surface of a high-temperature mold, the mold cavity surface is rapidly cooled. Therefore, there is a problem that heat cracks occur on the mold surface due to thermal shock. In addition, a time for applying the coolant to the mold cavity surface and a time for air blowing for removing moisture are required, and there is a limit to shortening the cycle time.

  Moreover, in the above-mentioned document 2, when cooling water comes into contact with the stress concentration part in the mold cooling hole, the mold cooling is promoted, but the stress concentration part may be cracked due to the temperature difference between the contact part and the mold. There is. Further, when the distance between the mold cavity surface and the tip of the cooling hole is made closer to improve the cooling capacity of the mold, the problem of cracking at the stress concentration portion becomes more serious.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a mold cooling apparatus capable of maintaining mold cooling performance while suppressing the occurrence of cracking due to thermal stress of the mold.

The first means taken in order to solve the above-mentioned problem is a cooling pipe for supplying a coolant to a cooling hole formed in a mold, a jig inserted into the cooling hole, a jig attached to the jig, And a heat insulating layer that is pressed against and pressed against the stress concentration portion of the cooling hole by pressing the jig from the bottom surface portion .

  In the second problem solving means, the heat insulating layer is formed in an annular shape.

  In the third problem solving means, the heat insulating layer is made of a resin material.

  In a fourth problem solving means, the jig includes a ring disposed at both ends of the jig and a plurality of support columns that support the ring.

According to a fifth problem solving means, the heat insulating layer is pressed by pressing the jig from the bottom surface, and the support is elastically deformed to fix the jig and the cooling hole. It is a configuration. Further, a sixth problem solving means includes a straight thread portion formed by drilling in the cooling hole, and screwed into the straight thread portion to press the heat insulating layer through the cooling pipe and the jig. And a screw plug to be further configured.

  According to the present invention, the jig with the heat insulating layer attached is inserted into the cooling hole and pressed against the stress concentration portion to be pressed against the stress concentration portion. It is possible to suppress and change the temperature gradient. Therefore, the generation of cracks due to the thermal stress of the mold can be suppressed. Moreover, it becomes possible to narrow the space | interval of a cooling hole and a mold cavity surface, and the improvement of a mold cooling capability can be aimed at.

  In addition, since the heat insulating layer is formed in an annular shape, a uniform pressure contact is obtained in an annular shape when the heat insulating layer is pressed, and generation of a gap between the cooling hole inner peripheral surface and the heat insulating layer can be suppressed.

  Further, since a resin material is used as the heat insulating layer, when pressed by a jig, the heat insulating layer is deformed along the inner wall of the cooling hole, so that the sealing performance is improved.

  In addition, the plurality of struts constituting the jig press the heat insulating layer with a uniform pressing force by the rings disposed at both ends of the jig. Therefore, the heat insulation layer can be stably fixed inside the cooling hole. That is, by providing a ring corresponding to the shape of the cooling hole, it is possible to stably fix the heat insulating layer inside the cooling hole.

  Further, when the jig support is pressed, it is elastically deformed toward the inner wall side of the cooling hole and presses the heat insulation layer with a constant pressing force. Therefore, it is possible to prevent an excessive pressing force from acting on the heat insulating layer, and to extend the life of the heat insulating layer. Moreover, since the support has a flat surface on the inner wall side of the cooling hole, the adjustment range is widened because the adjustment of the pressing force and the amount of elastic deformation are increased.

It is sectional drawing of the cooling structure of a metal mold | die. It is a front view of the jig which attached the heat insulation layer. It is AA sectional drawing of a jig.

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

  FIG. 1 is a cross-sectional view of the cooling structure of the mold 100 in this embodiment. The mold 100 includes a mold cavity surface 110 for producing a casting and a cooling hole 120 for cooling the mold 100 from the inside. The cooling hole 120 is formed by drilling, and includes a straight screw portion 130 that fixes the screw plug 240 and a taper screw portion 131 that fixes the cooling pipe 250. The mold cooling apparatus 200 inserted into the cooling hole 120 includes a jig 210 having four columns 211 and two rings 212 a and 212 b having different diameters fixed to both ends of the column 211, and one end side of the jig 210. A heat insulating layer 220 provided with a hole 221 for passing cooling water, a cylindrical pipe 230 (cooling pipe) that presses the jig 210, and a straight threaded portion 130 screwed into the pipe 230 and the jig 210. A screw plug 240 that presses and adjusts the heat insulating layer 220, a cooling pipe 251 that supplies cooling water, and a drain plug 252 that drains the cooling water, and a cooling plug 250 that is screwed into the taper screw portion 131. Is done.

  FIG. 2 is a front view of the jig 210 to which the heat insulating layer 220 is attached. The jig 210 includes four columns 211 and a ring 212a and a ring 212b fixed to the ends of the columns 211 in the longitudinal direction. The tip portions of the four support columns 211 are bent inward. The heat insulating layer 220 has a shape that matches the appearance of the column 211 in order to make it easy to attach and detach the tip of the column 211.

  Here, in this embodiment, the cooling hole 120 has a circular cross section in order to obtain a uniform cooling effect. At this time, by providing the ring 212a and the ring 212b corresponding to the cooling hole 120 having a circular cross section, the heat insulating layer 220 can be pressed against the inner wall of the cooling hole 120 with a uniform pressing force. Therefore, the heat insulating layer 220 can be stably fixed inside the cooling hole 120. That is, by providing the ring corresponding to the shape of the cooling hole 120, the heat insulating layer 220 can be stably fixed inside the cooling hole 120.

  Moreover, the four support | pillars 211 exhibit a cone shape as it goes to the ring 212a direction from the ring 212b. By exhibiting a conical shape, when the pressing force is applied from the bottom surface portion of the jig 210, the support column 211 easily spreads toward the inner wall of the cooling hole 120 by the restraint of the tip portion and the pressing from the bottom surface portion, and the reliable jig 210. Can be fixed. Further, by adopting a conical shape, a space between the cooling hole 120 and the jig 210 can be secured at the distal end portion of the healing path 210. Thereby, the thickness of the resin material can be selected according to the specifications, and the degree of freedom in setting the temperature gradient is increased.

  The jig 210 and the pipe 230 are made of a SUS material that does not easily corrode. A heat insulating layer 220 that insulates the stress concentration portion 121 where thermal stress generated during mold cooling is concentrated is attached to the front end portion of the heat insulating layer 220. The heat insulating layer 220 is formed in an annular shape, and a hole 221 for cooling the tip of the cooling hole 120 through the cooling water is provided in the central portion. The material of the heat insulation layer 220 is a fluororesin (resin material) that has elasticity and is excellent in heat insulation and heat resistance.

  By using the heat insulating layer 220 as a resin material in this way, the shape can be easily deformed as compared with ceramics, metals, and the like, and the heat insulating layer 220 can be brought into close contact with the shape of the cooling hole 120 and the heat insulating property can be improved. Furthermore, by using a resin material, it has higher flexibility than ceramics, metal, etc., and shape deformation is easy, so that pressing force during assembly can be suppressed. Thereby, the assembly | attachment of the metal mold cooling apparatus 200 can be performed simply. Further, the pressing force can be reduced with a simple structure, and the life of the jig 210 can be extended. Note that the degree of adhesion of the heat insulating layer 220 to the cooling hole 120 in the present invention is not limited to the one that completely prevents the refrigerant from entering, and the mold material and the refrigerant are not allowed to flow actively. The effect of the present invention can be obtained depending on the amount of water flow.

  FIG. 3 is a cross-sectional view of the jig 210 in FIG. Each of the four columns 211 has one plane 213 on the inner wall side of the cooling hole 120, and the plane 213 is configured to contact the inner wall of the cooling hole 120 when the ring 212 b is pressed and the column 211 is elastically deformed. . In the present embodiment, the cross-sectional shape of the support column 211 is a semicircle having a flat surface, but is not limited to a semicircle, and may be a quadrangular shape or other polygonal shapes.

  The procedure for attaching the mold cooling device 200 to the mold 100 will be described below.

  The jig 210 to which the heat insulating layer 220 is attached is inserted into the cooling hole 120 from the heat insulating layer 220 side. There are a plurality of cooling holes depending on the mold, and the depth is different. Therefore, by using pipes having different lengths according to the depth of the cooling holes, it is possible to cope with cooling holes having different depths.

  Next, the pipe 230 is pressed by the screw plug 240 screwed with the straight screw portion 130 in order to make close contact with the jig 210 to which the heat insulating layer 220 is attached via the pipe 230. Thereafter, the cooling plug 250 is attached to the taper screw part 131 and the cooling hole 120 is plugged.

  The cooling pipe 251 on the cooling plug 250 side is connected to the cooling water supply source 300 via the supply pipe 301. The drainage port 252 is connected to the cooling water drainage source 400 through the drainage pipe 401. As the cooling supply source 300, for example, a utility pipe discharge port using industrial water piped in a factory or the like is used. As the cooling water discharge source 400, for example, a utility pipe discharge port using industrial water piped to a factory or the like is used. Generally, the cooling water discharged from the outlet of the utility pipe is cooled and purified by a cooling tower or the like, and constitutes a circulation system that returns to the outlet of the utility pipe.

  In the above configuration, the cooling water supplied from the cooling water supply source 300 is jetted into the cooling hole 120 from the cooling pipe tip 251 a via the supply pipe 301 and the cooling pipe 251. The cooling water passes through the hole 221 of the heat insulating layer 220 and cools the tip of the cooling hole 120. At that time, since the stress concentration portion 121 is covered and sealed by the heat insulating layer 220, the cooling water does not contact the stress concentration portion 121. The cooling water from the cooling hole 120 toward the drain outlet 252 reaches the cooling water discharge source 400 via the drain pipe 401 and is discharged.

  In the mold cooling apparatus 200 of the present invention, since the screw plug 240 presses the heat insulating layer 220 through the pipe 230 and the jig 210, the heat insulating layer 220 is brought into close contact with the stress concentration portion 121 of the cooling hole 120. The part 121 can be sealed from the cooling water. By sealing from the cooling water, the thermal stress of the stress concentration portion 121 can be relaxed. Therefore, the generation of cracks due to the thermal stress of the mold 100 can be suppressed. In addition, the interval between the cooling hole 120 and the mold cavity surface 110 can be reduced, and the mold cooling capacity can be improved.

  In addition, since the heat insulating layer 220 is formed in an annular shape, when the heat insulating layer 220 is pressed, a uniform contact is obtained in an annular shape, and a gap is generated between the inner peripheral surface of the cooling hole 120 and the heat insulating layer 220. And the sealing performance is improved.

  In addition, since a fluorine-based resin is used as the heat insulating layer 220, when the jig 210 is pressed, the heat insulating layer 220 is deformed and adhered along the inner wall of the cooling hole 120, so that the sealing performance is improved.

  Further, by providing the ring 212a and ring 212b corresponding to the cooling hole 120 having a circular cross section and the four columns 211 supporting the ring 212a and ring 212b, the inner wall of the cooling hole 120 can be formed with a uniform pressing force. The heat insulating layer 220 can be stably fixed inside the cooling hole 120.

  Further, when the support column 211 of the jig 210 is pressed, it is elastically deformed toward the inner wall side of the cooling hole 120 and presses the heat insulating layer 220 with a constant pressing force. Therefore, it is possible to prevent an excessive pressing force from acting on the heat insulating layer 220 and to extend the life of the heat insulating layer 220. Moreover, since the support | pillar 211 has the plane 213 on the inner wall side of the cooling hole 120, adjustment of a pressing force and the amount of elastic deformation become large, and the adjustment range expands.

  In the conventional mold, in order to suppress the occurrence of cracks due to the thermal stress of the mold, the distance between the cooling hole 120 (cooling hole diameter φ11.5 mm) and the mold cavity surface 110 is 30 mm. In the example, since the stress value of the stress concentration portion 121 was relaxed, the distance between the cooling hole 120 and the mold cavity surface 110 can be reduced to about 5 mm. The cooling capacity index at this time was about 6 times that of the conventional mold (cooling water temperature 20 ° C., flow rate 7 L / min).

DESCRIPTION OF SYMBOLS 100 Mold 120 Cooling hole 121 Stress concentration part 200 Mold cooling device 210 Jig 220 Heat insulation layer 230 Pipe (cooling pipe)

Claims (6)

A cooling pipe for supplying a coolant to cooling holes formed in the mold;
A jig inserted into the cooling hole;
A mold cooling apparatus provided with a heat insulating layer attached to the jig and pressed against the stress concentration portion of the cooling hole by pressing the jig from the bottom surface portion . The mold cooling apparatus according to claim 1, wherein the heat insulating layer is formed in an annular shape. The mold cooling device according to claim 1, wherein the heat insulating layer is made of a resin material. The said jig | tool is provided with the ring arrange | positioned at the both ends of this jig | tool, and the some support | pillar which supports this ring, The gold | metal | money as described in any one of Claim 1 thru | or 3 characterized by the above-mentioned. Mold cooling device. The said jig | tool is pressed from a bottom face part, the said heat insulation layer is pressed, and the said support | pillar is elastically deformed and fixation between the said jig | tool and the said cooling hole is performed. Mold cooling system. A straight thread formed in the cooling hole by drilling;
  A screw plug that is screwed into the straight thread portion and presses the heat insulating layer via the cooling pipe and the jig;
The mold cooling device according to any one of claims 1 to 5, further comprising:

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