JP2009202196A - Die cooling mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die cooling mechanism for cooling a cooling medium to the prescribed part of a die performing molding where the cooling of the die by the cooling medium is performed at high precision. <P>SOLUTION: The die cooling mechanism 10 includes: a cooling water circulation forward path 24 connected with a cooling water feed source 22 and the cooling water inlet 18 of a second die 16; and a cooling water circulation backward path 28 connected with a cooling water recovery mechanism 26 recovering cooling water exhausted from the second die 16. The cooling water circulation forward path 24 is provided with a flow rate control circuit 32 and a cross valve 34 from the upstream side in this order. Among three ports provided at the cross valve 34, the two ports function as the inlet from the cooling water circulation forward path 24 and the outlet of the cooling water circulation backward path 24, and the remaining one functions as a bypass path 36 going to the cooling water circulation backward path 28. The bypass path 36 introduces the cooling water circulating through the cooling water circulation forward path 24 into the cooling water circulation backward path 28 without making the same to undergo the second die 16. Then, e.g., when a molten metal is introduced into the second die 16, the bypass path 36 is cut-off with the switching of the cross valve 34, and the feed of the cooling water to the second die 16 is started. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mold cooling mechanism for cooling a cooling medium to a predetermined part of a mold for performing molding.

  Casting processing in which a molten metal is introduced into a mold and cooled and solidified is one type of molding processing for obtaining a molded product, and has been widely practiced conventionally.

  In the case of casting, since the molten metal is hot, when the molten metal is introduced into the mold, the heat of the molten metal is transmitted to the mold, and the temperature of the mold rapidly increases accordingly. Such a rapid temperature rise causes seizure, and the yield of molded products is reduced. Therefore, it is a common practice to cool the mold by supplying a cooling medium such as cooling water to a predetermined part of the mold.

  However, if the mold temperature is excessively low, seizure can be prevented, but so-called hot water resistance is not good, and cracks may occur in the molded product. Therefore, in order to obtain a high quality product with good yield, it is necessary to control the mold temperature within an appropriate range.

  From such a viewpoint, Patent Document 1 aims to stabilize the mold temperature early, and starts supplying cooling water (cooling medium) when the mold temperature rises to a predetermined temperature. A temperature control method has been proposed in which the supply is stopped when the temperature of the mold drops to a predetermined temperature. The supply start and the supply stop are performed by opening and closing an electromagnetic valve and an electric valve arranged in a water channel for supplying cooling water to the mold.

JP 11-314147 A

  In short, the prior art described in Patent Document 1 starts or stops the circulation of the cooling water according to the temperature of the mold. However, in this case, for example, cooling water exceeding a necessary amount may be supplied to the mold. The reason is that until the solenoid valve or motorized valve is opened, the cooling water is blocked by these valves and is in a high pressure state. Therefore, when these valves are opened, a large amount of cooling water is generated. It is because it will be supplied to the mold at once. Accordingly, it takes about 5 to 10 seconds for the cooling medium flow rate control means to control the flow rate of the cooling water to a constant value. That is, the conventional technique described in Patent Document 1 has a problem that the response of the flow rate of the cooling water to the opening / closing of the electromagnetic valve or the motor-operated valve is not good.

  And there is a concern that the mold is excessively cooled due to this. In this case, it becomes difficult to ensure hot water circulation. On the other hand, if the circulation amount of the cooling water is reduced in order to avoid this problem, it is difficult to avoid seizure.

  The present invention has been made to solve the above-described problems, and has a quick response to the start and stop of supply of the cooling medium to the mold. For this reason, it is easy to control the temperature of the mold. It is an object of the present invention to provide a mold cooling mechanism capable of obtaining a quality molded product with a high yield.

In order to achieve the above object, the present invention provides a mold cooling mechanism for cooling a cooling medium to a mold for performing molding,
A cooling medium supply unit for supplying the cooling medium to the mold;
A cooling medium flow forward path through which the cooling medium flows and is connected to the cooling medium supply unit and the mold;
Cooling medium flow rate control means for controlling the flow rate of the cooling medium in the cooling medium flow path;
A cooling medium circulation return path through which the cooling medium discharged from the mold is cooled by cooling the mold;
With
A three-way valve is interposed downstream of the cooling medium flow control means in the cooling medium flow forward path, and a bypass path is formed through which the cooling medium flows from the three-way valve toward the cooling medium flow return path,
By switching the three-way valve, the cooling medium is circulated toward the mold via the cooling medium circulation forward path, or the cooling medium is circulated through the bypass path to the mold. Whether to stop the supply of the cooling medium is selected.

  When cooling is performed by this mold cooling mechanism, the cooling medium is circulated to the cooling medium circulation return path via the cooling medium circulation amount control means, the three-way valve, and the bypass path even when the cooling water is not supplied to the mold. For this reason, the amount of the cooling medium flowing through the inside of the cooling medium flow control means is always constant.

  And when it is necessary to supply cooling water to a metal mold | die, a three-way valve is switched from said state, and according to this, a bypass path is interrupted | blocked and a cooling-medium distribution | circulation outward path is open | released. Therefore, only the traveling direction of the cooling water is switched while the flow rate is substantially constant. Accordingly, a large amount of cooling water is not supplied to the mold at once, and there is no time lag until the cooling medium flow rate control means controls the flow rate of the cooling water to a constant value. Eventually, the mold is not cooled excessively, so that the temperature of the mold falls within an appropriate range, and the hot-rollability of the molten metal is ensured.

  On the other hand, seizure is avoided because the mold is cooled. After all, according to the present invention, a high-quality molded product can be manufactured with a high yield.

  A suitable example of the mold is a casting mold. In this case, the switching of the three-way valve may be controlled so that the cooling medium flows toward the mold when the molten metal is supplied to the mold. As a result, the temperature of the mold is controlled within an appropriate range, so that seizure can be more effectively avoided and the hot water supply performance can be improved.

  The three-way valve is preferably an air operated valve that operates with air. This type of valve responds quickly to control signals. Accordingly, since the traveling direction of the cooling medium can be immediately changed at the time of the above switching, the cooling medium can be prevented from being blocked during the switching. It becomes even easier to keep the amount of the cooling medium flowing through the inside of the interior of the storage medium constant.

  According to the present invention, a bypass valve capable of introducing a cooling medium into the cooling water circulation return path without passing through the mold from the cooling medium circulation outward path is provided, and the cooling medium is bypassed when it is not necessary to supply the cooling medium to the mold On the other hand, when the cooling medium is supplied to the mold, the bypass path is shut off and the cooling medium circulation forward path is opened. As a result, only the traveling direction of the cooling medium is switched while the amount of the cooling medium flowing through the inside of the cooling medium flow control means is kept constant. Accordingly, since the responsiveness becomes good, it becomes possible to supply a predetermined amount of cooling medium to the mold, and as a result, it is avoided that the mold is cooled excessively. Is secured.

  On the other hand, the occurrence of seizure due to cooling is avoided, so that a high-quality molded product can be manufactured with a high yield.

  Preferred embodiments of the mold cooling mechanism according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 shows a schematic configuration line diagram of a mold apparatus 12 provided with a mold cooling mechanism 10 according to the present embodiment. The mold apparatus 12 is for performing, for example, die casting, and has a first mold 14 and a second mold 16.

  Of course, the first mold 14 and the second mold 16 can be separated from each other and approached, and as both the first mold 14 and the second mold 16 are clamped as shown in FIG. A cavity (not shown) for obtaining is formed. Of course, this cavity is filled with molten metal supplied from a molten metal supply source (not shown).

  The mold cooling mechanism 10 according to the present embodiment is for introducing cooling water (cooling medium) into a predetermined part of the second mold 16. For this reason, the cooling water inlet 18 is provided in the second mold 16. And a cooling water outlet 20 is formed. Of course, the cooling water inlet 18 and the cooling water outlet 20 communicate with each other through a mold passage (not shown) formed in the second mold 16.

  The mold cooling mechanism 10 is discharged from a cooling water supply source 22 as a cooling medium supply unit, a cooling water circulation path 24 (cooling medium circulation path) connected to the cooling water inlet 18, and the second mold 16. A cooling water circulation return path 28 (cooling medium circulation return path) connected to the cooling water recovery mechanism 26 for recovering the cooling water.

  Among these, in the cooling water circulation path 24, a filter 30, a flow rate control circuit 32, and a three-way valve 34 are interposed in this order from the cooling water supply source 22 side, that is, upstream. Then, two of the three ports provided in the three-way valve 34 function as an inlet from the cooling water circulation forward path 24 and an outlet to the cooling water circulation forward path 24, respectively. It is an exit to the bypass path 36 toward the cooling water circulation return path 28.

  The filter 30 is for removing foreign matters such as dust contained in the cooling water. That is, the cooling water from which foreign matter has been removed by the filter 30 is introduced into the flow rate control circuit 32.

  The flow rate control circuit 32 is a cooling medium flow rate control means for controlling the flow rate of the cooling water supplied from the cooling water supply source 22. That is, the flow rate control circuit 32 has a valve mechanism (not shown) therein, and adjusts the opening degree of the valve mechanism so that the actual flow rate of the cooling water becomes a preset value. The flow rate of the cooling water increases as the opening degree of the valve mechanism increases, and decreases as the opening degree decreases.

  As described above, the three-way valve 34 is interposed in the cooling water circulation outward path 24 and becomes a starting point of the bypass path 36 toward the cooling water circulation return path 28. For this reason, the cooling water is introduced into the second mold 16 when the ones that function as the inlet / outlet of the cooling water circulation path 24 communicate with each other in the port of the three-way valve 34. On the other hand, when the port functioning as the inlet of the cooling water circulation path 24 and the port functioning as the outlet to the bypass path 36 communicate with each other, the coolant passes through the bypass path 36 without passing through the second mold 16. It is introduced into the cooling water circulation return path 28. Thus, the three-way valve 34 plays a role of selecting and switching the traveling direction of the cooling water.

  In this case, the three-way valve 34 is an air operated valve that operates under the action of instrument air. An air operated valve has the advantage that it is very responsive to control signals and therefore operates quickly.

  An air supply system (not shown) for supplying instrument air to the three-way valve 34 is electrically connected to a control circuit (not shown). A gate valve (not shown) disposed in a runner (not shown) for introducing the molten metal into the cavity is also electrically connected to the control circuit.

  The mold cooling mechanism 10 according to the present embodiment is basically configured as described above. Next, the function and effect will be described.

  For comparison, FIG. 2 shows a mold cooling mechanism 42 configured in the same manner as the mold cooling mechanism 10 according to the present embodiment except that a solenoid valve 40 is used instead of the three-way valve 34. . In FIG. 2, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The mold cooling mechanism 42 in FIG. 2 waits with the electromagnetic valve 40 closed while supplying cooling water from the cooling water supply source 22 before starting to fill the cavity with molten metal. Therefore, the cooling water is in a state of being blocked by the electromagnetic valve 40.

  When the gate valve is opened and filling of the molten metal into the cavity is started, the electromagnetic valve 40 is opened by the control signal generated by the control circuit, and as a result, the cooling water starts to flow toward the second mold 16. To do.

  However, in this case, the cooling water that has been dammed up by the electromagnetic valve 40 and becomes high pressure is discharged all at once. In other words, since a large amount of cooling water flows through the flow rate control circuit 32, for example, 5 to 10 seconds until the flow rate control circuit 32 sets the flow rate of the cooling water to a preset set flow rate. Requires some time.

  By the way, the time (injection time) until the introduction of the molten metal into the cavity is in units of seconds, and in some cases is less than 1 second. Therefore, in the mold cooling mechanism 42 configured as shown in FIG. 2 in which a large amount of cooling water is supplied at a time, the flow rate of the cooling water becomes stable and the temperatures of the first mold 14 and the second mold 16 can be controlled. The injection time may end before. In this case, since the temperature of the first mold 14 and the second mold 16 is difficult to rise, it is difficult to ensure the hot water circulation property, and the molded product is cracked. That is, it is difficult to manufacture a molded product with a high yield.

  On the other hand, in the mold cooling mechanism 10 according to the present embodiment shown in FIG. 1, the cooling water is supplied from the cooling water supply source 22 before the molten metal is filled into the cavity, and the three-way valve 34 is connected to the cooling water. The distribution outward path 24 and the bypass path 36 are connected. Accordingly, the cooling water flows through the cooling water circulation return path 28 without passing through the second mold 16. Of course, during this period, the flow rate of the cooling water is controlled by the flow rate control circuit 32 so as to be a preset flow rate.

  After the actual flow rate of the cooling water reaches a substantially constant value (set flow rate value), the gate valve is opened and filling of the molten metal into the cavity is started. At this time, the three-way valve 34 is switched by a control signal generated by the control circuit.

  Along with this switching, the bypass path 36 is blocked, and the cooling water circulation path 24 is opened from the cooling water supply source 22 to the cooling water inlet 18 of the second mold 16. Therefore, the cooling water starts to flow toward the second mold 16 and is discharged from the cooling water outlet 20 through the mold passage. Following this, the first mold 14 is also cooled. Finally, the cooling water passes through the cooling water circulation return path 28 and is recovered by the cooling water recovery mechanism 26.

  That is, in the mold cooling mechanism 42 shown in FIG. 2, the cooling water is circulated from the dammed state, whereas in the mold cooling mechanism 10 according to the present embodiment shown in FIG. The cooling water is circulated even when the cooling water is not supplied, and the traveling direction of the cooling water is switched when the cooling water needs to be supplied to the second mold 16. For this reason, the amount of cooling water flowing through the flow rate control circuit 32 can be made constant at all times.

  Therefore, even when the three-way valve 34 is switched to supply the cooling water to the second mold 16, the amount of the cooling water flowing through the flow rate control circuit 32 does not vary significantly. As a result, the temperature of the first mold 14 and the second mold 16 can be raised to an appropriate range, so that hot water circulation is ensured. Eventually, the occurrence of cracks in the molded product is avoided.

  Moreover, in this case, since an air operated valve is used as the three-way valve 34, the responsiveness is good. That is, since the three-way valve 34 is switched immediately in response to the control signal, the cooling water is not blocked from the start to the end of the switching of the three-way valve 34. In combination with this, it is possible to avoid the amount of the cooling water flowing through the flow rate control circuit 32 from fluctuating.

  Furthermore, it is also possible to avoid excessive cooling of the first mold 14 and the second mold 16 by setting the set flow rate value set in the flow rate control circuit 32 within an appropriate range.

  FIG. 3 is an example of the mold cooling mechanism 10 (see FIG. 1) according to the present embodiment, and the mold cooling mechanism 42 shown in FIG. 2 is a comparative example. It is a graph which shows the change of mold temperature with respect to the number of shots in the part which should be cooled when a mold is cooled. From FIG. 3, the mold cooling mechanism 10 according to the present embodiment does not excessively lower the temperature as compared with the mold cooling mechanism 42 of the comparative example, and can easily ensure hot water supply. Is understood.

  Further, FIG. 4 shows a graph showing a change in mold temperature with respect to the number of shots at a site separated from the in-mold passage. From FIG. 4, it can be seen that the mold temperature does not decrease excessively even when the mold cooling mechanism 10 is configured as shown in FIG. That is, the hot water circulation property is ensured also in this part.

  When casting was performed without supplying cooling water to the mold, seizure occurred at the seventh cycle.

  As described above, it is necessary to supply the cooling water to the mold after the mold cooling mechanism 10 according to the present embodiment is attached and the cooling water is always in the circulation amount control circuit. For the first time, by changing the traveling direction of the cooling water and supplying the cooling water to the mold, seizure can be avoided and hot water circulation can be ensured. Therefore, a high-quality molded product can be manufactured with a high yield.

  In the above-described embodiment, the cooling water is circulated as the cooling medium. However, the cooling medium is not particularly limited to this. For example, other cooling medium such as oil may be used. Good.

  Further, the mold for performing the molding process is not limited to the above-described casting process, and may be an injection molding process mold.

  Furthermore, the supply of cooling water to the mold may not necessarily start simultaneously with the supply of molten metal.

1 is a schematic configuration line diagram of a mold apparatus provided with a mold cooling mechanism according to the present embodiment. FIG. 2 is a schematic configuration line diagram of a mold apparatus provided with a mold cooling mechanism (comparative example) in which an electromagnetic valve is used instead of the three-way valve of FIG. 1. FIG. 3 is a graph showing a change in mold temperature with respect to the number of shots at a portion to be cooled in the mold when the mold cooling mechanism of FIG. 1 or FIG. 2 is used. FIG. 3 is a graph showing a change in mold temperature with respect to the number of shots at a site separated from the far stomach pain path in the mold when the mold cooling mechanism of FIG. 1 or FIG. 2 is used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 42 ... Mold cooling mechanism 12 ... Mold apparatus 14, 16 ... Mold 22 ... Cooling water supply source 24 ... Cooling water circulation outward path 26 ... Cooling water recovery mechanism 28 ... Cooling water circulation return path 32 ... Flow control circuit 34 ... Three-way Valve 36 ... Bypass passage 40 ... Solenoid valve

Claims (3)

A mold cooling mechanism for cooling a cooling medium to a mold for molding,
A cooling medium supply unit for supplying the cooling medium to the mold;
A cooling medium flow forward path through which the cooling medium flows and is connected to the cooling medium supply unit and the mold;
Cooling medium flow rate control means for controlling the flow rate of the cooling medium in the cooling medium flow path;
A cooling medium circulation return path through which the cooling medium discharged from the mold is cooled by cooling the mold;
With
A three-way valve is interposed downstream of the cooling medium flow control means in the cooling medium flow forward path, and a bypass path is formed through which the cooling medium flows from the three-way valve toward the cooling medium flow return path,
By switching the three-way valve, the cooling medium is circulated toward the mold via the cooling medium circulation forward path, or the cooling medium is circulated through the bypass path to the mold. Whether to stop the supply of the cooling medium is selected.   2. The mold cooling mechanism according to claim 1, wherein the mold is a casting mold, and the cooling medium flows toward the mold when molten metal is supplied to the mold. 3. A mold cooling mechanism in which a valve is switched.   3. The mold cooling mechanism according to claim 1, wherein the three-way valve is an air operated valve operated by air.

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