JP4518012B2 - Mold cooling structure and cooling method - Google Patents

Description

  The present invention relates to a mold cooling structure and a cooling method used in a so-called broad mold casting method (die casting method) and a resin molding method, and more particularly to forced cooling by passing a cooling medium through cooling holes for mold cooling. The present invention relates to a mold cooling structure and a cooling method.

  For example, in the low pressure casting method, which is one of the so-called mold casting methods in a broad sense, the die may be cooled in order to promote the solidification of the molten metal filled in the die and shorten the cycle time. Has been done.

This type of technology includes direct cooling type cooling technology in which a cooling medium is passed through cooling holes formed in the mold and heat is directly exchanged between the cooling medium and the mold. Insert a cooling pipe with the same diameter and good thermal conductivity into the hole, and let the cooling medium flow through the cooling pipe, so that the cooling medium is heated between the mold and the mold through the cooling pipe. There is an indirect cooling type cooling technique to be replaced, and both of these techniques are described in Patent Document 1. Moreover, in the indirect cooling type cooling technology, the outer peripheral surface of the cooling pipe is locally cut out at a position corresponding to a specific part of the cooling pipe to reduce the thickness between the mold and the cooling pipe. An air insulation layer is formed, and the cooling medium has a different cooling effect on the mold between the part where the air insulation layer is formed and the part where it is not, and each part of the mold is cooled under appropriate cooling conditions. It has also been proposed.
Japanese Patent No. 2762563

  In order to cool the mold, it is necessary to cool each part of the mold under appropriate cooling conditions according to the thickness of each part of the product, the casting method, etc. In order to obtain a good quality product, Among them, the cooling effect of the cooling medium on the mold is significantly different between the part that requires cooling and the part that does not, so that only the part requiring cooling of the mold is partially reduced without reducing the temperature of the entire mold as much as possible. It is desirable to cool.

  However, in the direct cooling type cooling technology, since the cooling medium is always in direct contact with the mold not only at the required cooling portion of the mold but also along the entire length of the cooling hole, the temperature of the mold as a whole cannot be reduced. There is a limit to partially cooling only a specific part of the mold.

  Further, in the indirect cooling type cooling technology, since a cooling pipe is always interposed between the cooling medium and the mold, the cooling effect of the cooling medium on the mold becomes slow as a whole, Even if an air heat insulation layer is provided between the molds, the thickness of the air heat insulation layer is limited by the thickness of the pipe, so there is a problem that it is difficult to have a difference in cooling effect between each part of the mold. .

  The present invention has been made paying attention to the above-mentioned problems, and the difference in the cooling effect between the portion requiring cooling of the mold and the portion not cooling is conspicuous, and the portion requiring cooling of the mold is partially and efficiently provided. It is an object of the present invention to provide a mold cooling structure and a cooling method capable of cooling.

According to the first aspect of the present invention, a cooling hole is formed in a part of a mold for forming a product of a predetermined shape by filling a product shape portion space with a molten material and cooling and solidifying the space. Is assumed to be a mold cooling structure that inserts a pipe through which a cooling medium flows and forcibly cools a specific part of the mold, and then inserts a pipe from each end of the cooling hole. together, by its is separated by a predetermined distance in a non-continuous tips of both pipes at a position corresponding to a specific portion of the inner mold cooling holes non butted state, those wherein a portion of the cooling holes A cooling chamber is formed in which the inner wall surface of the cooling hole and the cooling medium are in direct contact with each other and has a cooling effect greater than that of other parts of the cooling hole, and a specific part of the mold is forcibly cooled with this cooling chamber. As a feature There.

  Here, as a mold, in addition to a mold used in a so-called broad mold casting method, a mold used in a resin molding method represented by an injection molding method is also a target.

Furthermore, as described in claim 2, the provision of a heat insulating layer between the inner peripheral surface of both pipes and the inner wall surface of the cooling hole has a large cooling effect in the cooling chamber and other portions. It is desirable to provide a difference. Specifically, as described in claim 3 , an air heat insulating layer is provided between both pipes and the inner wall surface of the cooling hole, and cooling is provided at the tips of both pipes. A seal portion is provided for sealing between the chamber and the air insulation layer while isolating the chamber and the air insulation layer.

The invention described in claim 7 comprising which is assumed as a cooling method the techniques described in claim 1, gold for molding a product having a predetermined shape by cooling and solidifying by filling a molten material into the product shape portion space This is a mold cooling method in which a cooling hole is formed through a part of the mold, a pipe is inserted into the cooling hole, and a cooling medium is passed through the pipe to forcibly cool a specific part of the mold. Based on the premise, pipes are inserted from both ends of the cooling holes, and the tips of both pipes are discontinuously separated from each other by a predetermined distance at positions corresponding to specific parts of the mold. with non-abutting state, also form a large cooling chamber of the cooling effect than other parts of the cooling holes in a part of the cooling holes, the cooling water and the inner wall surface of the cooling hole at the cooling chamber directly the contacted Part specific to mold It is characterized in that forced cooling of.

Therefore, in the invention according to at least claims 1 and 7, the cooling medium flowing through the mold is in direct contact with the inner wall surface of the cooling hole at a specific portion of the cooling holes while forcibly cooling the mold. In other parts of the cooling hole, the cooling medium and the inner wall surface of the cooling hole are insulated without being in direct contact with each other, so that the cooling effect of the cooling medium on the mold is remarkably slow. As a result, it is possible to efficiently cool only a specific part of the die that is locally limited without affecting other parts other than the specific part of the mold.

According to the first and seventh aspects of the invention, the cooling medium and the mold are in direct contact with each other at a specific part of the cooling hole, whereas the cooling medium is in direct contact with the mold at other parts of the cooling hole. Therefore, the cooling effect on the specific part of the mold is significantly larger than the cooling effect on the other part of the mold, and only the specific part of the mold can be effectively cooled without cooling the mold as a whole. is there.

  FIG. 1 is a vertical sectional view showing a low pressure casting mold 1 to which a mold cooling structure according to the present invention is applied as a preferred embodiment of the present invention.

  The mold 1 includes an upper mold 2 and a lower mold 3, and a cavity R is formed as a product shape portion space with the upper mold 2 and the lower mold 3 being clamped as shown in FIG. A product having a predetermined shape is cast by filling the cavity R with a molten metal such as an Al alloy or Zn alloy and cooling and solidifying the melt.

  The lower die 3 has a uniform diameter and straight cooling hole 4 penetrating the lower die 3 in the horizontal direction. The cooling hole 4 has an inflow pipe 5 and an outflow pipe 6 described later from both ends thereof. Removably fixed while inserting each. Both the inflow pipe 5 and the outflow pipe 6 are made of metal having a heat resistance and a thermal expansion coefficient larger than that of the material of the lower mold 3, and each is a circular pipe having the same shape, and the inflow pipe 5 is coupled to one end of the cooling hole 4. The outflow pipe 6 is connected to the inflow hose 8 outside the mold 1 through the inflow nipple 7, while the outflow pipe 6 is connected to the other end of the cooling hole 4 through the outflow nipple 9. It is connected to the. Thereby, the temperature-controlled cooling water flows through the inside of the inflow pipe 5 and the outflow pipe 6 as a cooling medium. In addition to water, a liquid such as oil or a gas such as compressed air may be used as the cooling medium.

  In addition, the tips of both pipes 5 and 6 are discontinuously separated from each other by a predetermined distance at a position corresponding to a required cooling portion P that needs to be cooled in order to prevent a casting defect due to a solidification delay in the cooling hole 4. The cooling chamber 11 that allows the flow of the cooling water is formed by setting the non-matching state. That is, the inflow pipe 5, the cooling chamber 11, and the outflow pipe 6 constitute a cooling pipe line through which the cooling medium flows.

  Both pipes 5 and 6 are composed of general portions 5b and 6b and seal portions 5a and 6a that are stretched in the form of flanges at their tips. An air heat insulating layer 12 is interposed between the outer wall surface of the general parts 5b and 6b and the inner wall surface of the cooling hole 4 by setting the outer diameter of the general parts 5b and 6b to be smaller than the cooling hole 4. By setting the outer diameter of the seal portions 5a and 6a to be substantially the same as that of the cooling hole 4, the air insulation layer 12 and the cooling chamber 11 are separated from each other by the seal portions 5a and 6a. Sealed.

  In the cooling structure of the mold 1 configured as described above, the lower mold 3 that has become high temperature during the casting operation is thermally expanded and the cooling hole 4 has a large diameter, but the seal portions 5a and 6a are more than that. Due to the thermal expansion, there is no gap between the seal portions 5a, 6a and the lower mold 3, and a so-called interference fit state is established, and the space between the air heat insulation layer 12 and the cooling chamber 11 is reliably sealed.

  In the process in which the cooling water flows through the cooling holes, the cooling water directly contacts the inner wall surface of the cooling holes 4 in the cooling chamber 11 and directly exchanges heat with the lower mold 3. In both the pipes 5 and 6 for supplying and discharging the cooling water to and from the chamber 11, the cooling water does not come into direct contact with the inner wall surface of the cooling hole 4. Therefore, the cooling effect in the part corresponding to the cooling chamber 11 in the lower mold 3 and the other parts can be greatly different.

  Therefore, according to the cooling structure as described above, the cooling water is supplied to and discharged from the cooling chamber 11 while reliably insulating the lower mold 3. While the forced cooling is directly performed by the cooling water, the cooling effect in the other parts of the lower mold 3 is remarkably slow, and the cooling effect is greatly changed between the part requiring the cooling of the mold 1 and the part that is not. Cooling with a so-called beam can be performed. That is, it becomes possible to partially and efficiently cool only a specific part of the mold 1 corresponding to the part P requiring cooling of the product without lowering the temperature of the mold 1 as a whole.

  In addition, when it is necessary to review the cooling conditions after several times of casting and checking the finished product, the position of the cooling chamber 11 is changed by changing the lengths of both pipes 5 and 6. And by adjusting the length, the cooling conditions can be easily changed without remaking the mold 1, which is advantageous in terms of cost and time compared to remaking the mold 1.

  In particular, when the cooling hole 4 is long, holes are formed from both ends of the cooling hole 4 and the holes are made continuous to form the cooling hole 4 through the lower mold 3. Since both pipes 5 and 6 do not exist, both pipes 5 and 6 are cooled even if a slight level difference occurs in the cooling chamber 11 that is a continuous part of the holes when the cooling holes 4 are formed through. The cooling hole 4 can be easily processed and is advantageous in terms of cost.

  In the above embodiment, the mold cooling structure according to the present invention is applied only to the lower mold 3, but it goes without saying that it can be applied to other mold elements such as the upper mold 2 as necessary.

  FIG. 2 is a diagram showing a second embodiment of the present invention, and is a horizontal sectional view showing a cooling pipe line in the lower die 14 of the die 13 for low pressure casting. In FIG. 2, the same reference numerals as those in FIG.

  In the second embodiment, as shown in FIG. 2, the basic structure of the cooling pipe is the same as that of the first embodiment, and cooling holes 15 penetrating the lower mold 14 are formed in the cooling chamber 16. It is bent by a predetermined angle at a corresponding position. Further, in order to improve the sitting of the seating surface of the outflow nipple 9 coupled to the lower mold 13, a counterbore portion 17 is provided at the cooling water outflow side end of the cooling hole 15. Therefore, while the cooling water is in direct contact with the lower mold 14 in the cooling chamber 16, the cooling water in both the pipes 5 and 6 is insulated from the lower mold 14 as in the first embodiment. The same effects as those in the first embodiment are obtained. In addition, since the cooling holes 4 are bent in the cooling chamber 11, the layout of the cooling pipes is highly flexible, and the workability and safety are ensured in addition to the consistency with other equipment of the casting equipment. There is an advantage to be advantageous.

  3-5 is a figure which shows the 3rd-5th embodiment of this invention, Comprising: The modification of the cooling pipe line in 1st Embodiment is shown. 3 to 5, the same or corresponding parts as those in FIG. 1 described above are denoted by the same reference numerals.

  In the third embodiment shown in FIG. 3, the cooling hole 20 formed through the lower mold 19 in the mold 18 is drilled from the cooling water upstream side and the cooling water 20a is drilled from the cooling water downstream side. A so-called stepped type comprising a large-diameter cooling hole 20b larger than the small-diameter cooling hole 20a is provided, and the cooling chamber 21 is provided so as to straddle both the small-diameter cooling hole 20a and the large-diameter cooling hole 20b. In addition, the inner diameter of the outflow pipe 22 is larger than the inner diameter of the inflow pipe 5, and the inner diameters of the outflow nipple 23 and the outflow hose 24 are also larger than the inner diameters of the inflow nipple 7 and the inflow hose 8, respectively. The basic structure of the cooling pipe is the same as that of the first embodiment, and the outflow pipe 22 includes a seal portion 22a and a general portion 22b.

  According to the third embodiment, the same effects as those of the first embodiment can be obtained, and when the cooling water comes into contact with the lower mold 19 in the cooling chamber 21, the cooling water vaporizes explosively. However, since the expanded cooling water is smoothly discharged from the cooling chamber 20 by setting the inner diameter of the outflow pipe 22 to be larger than the inner diameter of the inflow pipe 5, There is a merit that the time lag that occurs between when the flow is made and the cooling effect appears is alleviated, and the responsiveness of the cooling effect in the mold 18 is improved.

  In the fourth embodiment shown in FIG. 4, of the inflow pipe 25 and the outflow pipe 26 each composed of the seal portions 25a and 26a and the general portions 25b and 26b, the seal portions 25a and 26a are directed toward the other pipe. The inner diameter of both the pipes 25 and 26 and the inner wall surface of the cooling hole 4 are made continuous without any step. The basic structure of the cooling pipeline is the same as that of the first embodiment.

  According to the fourth embodiment, the same effects as those of the first embodiment can be obtained, and when the cooling water flows into the cooling chamber 11 from the inflow pipe 25 and from the cooling chamber 11 to the outflow pipe 26. By gently changing the cross-sectional area of the cooling pipe when discharged, there is an advantage that the cooling water flow resistance is reduced and the cooling performance is improved.

  In the fifth embodiment shown in FIG. 5, the basic structure of the cooling pipe is the same as that of the first embodiment, and cooling is performed in a cooling hole 29 formed through the lower mold 28 of the mold 27. In the center of the chamber 30, a constricted portion 31 having a reduced cross-sectional area is provided. In addition to the effect of the first embodiment, the cross-sectional area of the flow of cooling water is reduced in the constricted portion 31. As a result, the flow rate of the cooling water is increased, and the contact area between the cooling water and the lower mold 28 is increased, so that the cooling performance is improved.

  For example, the cooling holes can be bent as in the second embodiment and at the same time the cooling holes can be stepped as in the third embodiment. Of course, it is possible to combine the features of the cooling pipes in the fifth embodiment.

It is a figure which shows the 1st Embodiment of this invention and is a vertical sectional view of the low-pressure casting mold. It is a figure which shows the 2nd Embodiment of this invention, and is a horizontal sectional view of a lower mold | type among low pressure casting molds. It is a figure which shows the 3rd Embodiment of this invention, and is a vertical sectional view of the low-pressure casting mold. It is a figure which shows the 4th Embodiment of this invention, and is a vertical sectional view of the low-pressure casting mold. It is a figure which shows the 5th Embodiment of this invention, and is a vertical sectional view of the low-pressure casting mold.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold 4 ... Cooling hole 5 ... Inflow pipe 5a ... Seal part 6 ... Outflow pipe 6a ... Seal part 11 ... Cooling chamber 12 ... Air insulation layer 13 ... Mold 15 ... Cooling hole 16 ... Cooling chamber 18 ... Mold 20 ... cooling hole 21 ... cooling chamber 22 ... outflow pipe 22a ... seal part 25 ... inflow pipe 25a ... seal part 26 ... outflow pipe 26a ... seal part 27 ... mold 29 ... cooling hole 30 ... cooling chamber 31 ... throttle part R ... cavity (Product shape space)

Claims (7)

The product shape part space is filled with a molten material and cooled and solidified to form a cooling hole in a part of a mold for forming a product of a predetermined shape, and a pipe through which a cooling medium flows is provided in the cooling hole. In the mold cooling structure that is inserted and forcedly cooled a specific part of the mold,
Pipes are inserted from both ends of the cooling holes, and the ends of both pipes are discontinuously separated from each other by a predetermined distance at a position corresponding to a specific portion of the mold in the cooling holes to be in a non-butting state. the inner wall surface and the cooling medium of those said cooling holes in a part of the cooling holes to form a large cooling chamber of the cooling effect than other parts of the direct contact and cooling holes, specific mold with the cooling chamber A mold cooling structure characterized in that the part is forcibly cooled. 2. The mold cooling structure according to claim 1, wherein a heat insulating layer is provided between the inner peripheral surface of both pipes and the inner wall surface of the cooling hole. An air insulation layer is provided between both pipes and the inner wall surface of the cooling hole, and a seal portion is provided at the tip of both pipes to seal between the two while isolating the cooling chamber and the air insulation layer. The mold cooling structure according to claim 2, wherein the mold cooling structure is provided. 4. The gold according to claim 3, wherein one pipe is used as a cooling medium inflow pipe and the other pipe is used as a cooling medium outflow pipe, and an inner diameter of the outflow pipe is larger than an inner diameter of the inflow pipe. Mold cooling structure. The tip of both pipes has a tapered shape with the inner diameter continuously expanding toward the other pipe, and the inner peripheral surface of both pipes and the inner wall surface of the cooling hole in the cooling chamber are made continuous without any step. The mold cooling structure according to claim 3 , wherein: 4. The mold cooling structure according to claim 3, wherein the cooling chamber has a narrowed portion formed by reducing a partial cross-sectional area thereof. By filling the product shape space with molten material and cooling and solidifying it, a cooling hole is formed in a part of the mold that molds the product of a predetermined shape, and a pipe is inserted into the cooling hole, and the pipe is cooled. A mold cooling method for forcibly cooling a specific part of a mold by flowing a medium,
Pipes are inserted from both ends of the cooling holes, and the ends of both pipes are discontinuously separated from each other by a predetermined distance at a position corresponding to a specific portion of the mold in the cooling holes to be in a non-butting state. As a result, a cooling chamber having a larger cooling effect than other parts of the cooling hole is formed in a part of the cooling hole, and the inner wall surface of the cooling hole and the cooling water are brought into direct contact with this cooling chamber so that a specific part of the mold is formed. A mold cooling method characterized by forced cooling.

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