Die casting machine

Abstract

To provide a die casting machine in which responsiveness of flow rate control of a cooling liquid is improved immediately after startup of the die casting machine.SOLUTION: A die casting machine 10 includes: a main circulation flow path 22 through which a cooling liquid for cooling a mold 12 circulates and flows; a main pump 36 that sends the cooling liquid to the main circulation flow path 22; a sub circulation flow path 50 through which the cooling liquid circulates and flows, the sub circulation flow path 50 being shorter than the main circulation flow path 22; and a sub pump 54 that sends the cooling liquid to the sub circulation flow path 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present specification discloses a die casting machine having a circulation channel for cooling the mold. [Background technology]

[0002] Generally, die-casting machines are provided with a circulation channel through which a cooling liquid circulates. This circulation channel passes through the mold, and the cooling liquid flowing through the circulation channel cools the mold and, ultimately, the product inside the mold.

[0003] For example, Patent Document 1 discloses a mold cooling mechanism for cooling a cooling medium in a mold. The mold cooling mechanism in Patent Document 1 has a refrigerant flow path, which has an outgoing path that guides the cooling medium to the mold, a returning path that guides the cooling medium that has left the mold, and a bypass path that connects the outgoing path and the returning path outside the mold. In Patent Document 1, when there is no need to cool the mold, the connection between the outgoing path and the mold is cut off and the cooling refrigerant is flowed through the bypass path, thereby preventing the mold from being overcooled. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-202196 Summary of the Invention [Problem to be solved by the invention]

[0005] Recently, it has been proposed to manufacture large products using die casting. For large products, the die casting machine itself is large, the circulation path through which the coolant flows is long, and the flow rate of the coolant increases. This has led to a problem of poor response in the coolant flow rate control immediately after starting the die casting machine.

[0006] Therefore, this specification discloses a die casting machine in which the responsiveness of the coolant flow rate control immediately after the start of the die casting machine is improved. [Means for solving the problem]

[0007] The die-casting machine disclosed in this specification is characterized by comprising a main circulation flow path through which a cooling liquid for cooling a mold circulates, a main pump that sends the cooling liquid to the main circulation flow path, a sub-circulation flow path through which the cooling liquid circulates and which is shorter than the main circulation flow path, and a sub-pump that sends the cooling liquid to the sub-circulation flow path.

[0008] In this case, the main circulation flow path may have an outward path that guides the cooling liquid toward the mold and a return path that guides the cooling liquid that has left the mold, the sub-circulation flow path may branch off from the return path and merge with the outward path, and the sub-pump may be provided in the sub-circulation flow path, and may send the cooling liquid from the return path through the sub-circulation flow path to the outward path.

[0009] Furthermore, the device may further include a first check valve and a second check valve arranged near the confluence of the outward path and the sub-circulation flow path, wherein the first check valve is arranged in the outward path at a position upstream of the confluence in the direction of travel of the outward path, and the second check valve is arranged in the sub-circulation flow path at a position upstream of the confluence in the direction of travel of the return flow path.

[0010] The output of the sub-pump may be smaller than the output of the main pump.

[0011] Furthermore, the system may further include a safety fence separating a non-working area from a working area, a main flow meter placed in the working area to measure the flow rate of the main circulation flow path, and a sub-flow meter placed in the non-working area to measure the flow rate of the sub-circulation flow path, and a portion of the main circulation flow path may pass through the working area, while the sub-circulation flow path may not pass through the working area.

[0012] The die-casting machine may further include a controller, which causes the cooling liquid to flow into the sub-circulation flow path during the first shot after the die-casting machine is started, and causes the cooling liquid to flow into the main circulation flow path during the second or subsequent shots, or when the temperature of the cooling liquid flowing into the sub-circulation flow path exceeds a reference value.

[0013] Another die-casting machine disclosed in this specification is characterized in that it comprises a circulation flow path through which a coolant for cooling a mold circulates, a plurality of flow meters that measure the flow rate in the circulation flow path, and a safety fence that separates a work area from a non-work area, and at least some of the plurality of flow meters are arranged in the non-work area and the remaining some are arranged in the work area. [Effects of the Invention]

[0014] According to the die casting machine disclosed in this specification, the responsiveness of the coolant flow rate control immediately after startup is further improved. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a diagram showing the configuration of a cooling circuit of a die-casting machine. [Figure 2] FIG. 10 is a diagram showing the flow of the coolant immediately after startup. [Figure 3] 10A and 10B are diagrams illustrating the flow of the coolant after the sub-circulation flow path is closed. [Figure 4] FIG. 10 is a diagram showing the configuration of another cooling circuit. DETAILED DESCRIPTION OF THE INVENTION

[0016] The configuration of a die-casting machine 10 will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a cooling circuit 20 of the die-casting machine 10. This die-casting machine 10 is a device that performs die-casting. For example, the die-casting machine 10 is a device that integrally molds large parts used in vehicles and aircraft, and is a device known as a mega-casting machine or giga-casting machine.

[0017] The die-casting machine 10 has a mold 12. In FIG. 1, the mold 12 is illustrated as a single block, but in reality, the mold 12 has a fixed mold and a movable mold. The fixed mold and the movable mold can move toward and away from each other, and a cavity space for obtaining a molded product is formed when the movable mold is clamped to the fixed mold. Molten metal is injected into this cavity space to fill it. Hereinafter, the process of injecting and filling the molten metal into the cavity space to obtain a molded product will be referred to as a "shot."

[0018] The mold 12 is replaced depending on the type of molded product to be produced. Furthermore, the mold 12 is subjected to thermal and pressure loads with each shot, and therefore gradually deteriorates as the shots are repeated. Therefore, even if the type of molded product remains the same, the mold 12 is replaced periodically or depending on the degree of deterioration. The mold 12 may be replaced in its entirety, or only a part of it may be replaced. For example, if the mold 12 has a insert that contacts the cavity space and a mother mold that holds the insert, only the insert may be replaced.

[0019] The die-casting machine 10 has a cooling circuit 20 for cooling the mold 12. The cooling circuit 20 is broadly divided into an in-mold flow path 30, a main circulation flow path 22, and a sub-circulation flow path 50. The in-mold flow path 30 is formed inside the mold 12 and is a flow path through which a cooling liquid flows. Although FIG. 1 shows two straight in-mold flow paths 30, in reality, the in-mold flow path 30 branches into more paths and is bent in a complex manner according to the shape of the molded product.

[0020] The main circulation flow path 22 is a flow path that communicates with the in-mold flow path 30 and circulates the coolant. The main circulation flow path 22 has an outgoing flow path 26 through which the coolant flows toward the in-mold flow path 30, and a return flow path 28 through which the coolant flows out of the in-mold flow path 30. Here, as shown in Fig. 1, the in-mold flow path 30 is divided into multiple systems (two in the illustrated example). In order to communicate with each of these multiple systems of in-mold flow paths 30, the terminal end of the outgoing flow path 26 and the starting end of the return flow path 28 are also divided into multiple systems.

[0021] Both the outgoing path 26 and the returning path 28 are provided outside the mold 12. Therefore, even if part or all of the mold 12 is replaced, the outgoing path 26 and the returning path 28 do not need to be changed. Hereinafter, the connection between the outgoing path 26 and the in-mold flow path 30 will be referred to as the "inlet connector 32," and the connection between the in-mold flow path 30 and the returning path 28 will be referred to as the "outlet connector 34."

[0022] The main circulation path 22 further includes a main pump 36, a heat exchanger 38, a tank 24, a main flow meter 40, and a main valve 42. The main pump 36 sends the coolant to the in-mold path 30 via the outward path 26. The tank 24 temporarily stores the coolant recovered via the return path 28. The coolant stored in the tank 24 is pumped up by the main pump 36 and supplied again via the outward path 26 to the in-mold path 30. The heat exchanger 38 exchanges heat with the outside air or a refrigerant to cool the coolant recovered from the in-mold path 30 to a predetermined temperature. The heat exchanger 38 is provided midway along the return path 28.

[0023] The main flow meter 40 is a sensor that measures the flow rate of the coolant flowing in the main circulation flow path 22, specifically, in the return path 28. Here, the starting end of the return path 28 is divided into multiple systems as shown in FIG. 1. A main flow meter 40 is provided in each of the multiple return paths 28. This makes it possible to measure the flow rate for each of the multiple in-mold flow paths 30.

[0024] The main valves 42 are disposed in the vicinity of the main flow meter 40 on each of the return lines 28 of the multiple systems. The main valves 42 are valves that open and close the corresponding return lines 28. The main valves 42 are solenoid valves that are electrically opened and closed in response to a control signal output from the controller 66. The main valves 42 may also be control valves that can control the flow rate, the pressure, or both. The controller 66 switches the opening and closing amount of the main valves 42 depending on the progress of die casting. Note that the configuration of the main circulation flow path 22 described above is merely an example. The main circulation flow path 22 may have other configurations as long as it can circulate the coolant flowing through the mold 12. For example, the heat exchanger 38 and the tank 24 described above may be omitted.

[0025] The cooling circuit 20 further has a sub-circulation flow path 50. The sub-circulation flow path 50 is a flow path through which the coolant flows, and is shorter than the main circulation flow path 22. This sub-circulation flow path 50 branches off from the return path 28 of the main circulation flow path 22 and merges with the outward path 26. As described above, the terminal end of the outward path 26 is divided into multiple systems, so the terminal end of the sub-circulation flow path 50 that merges with the outward path 26 is also divided into multiple systems. In addition, since the starting end of the return path 28 is divided into multiple systems, the starting end of the sub-circulation flow path 50 that branches off from the return path 28 is also divided into multiple systems. The reason for providing such a sub-circulation flow path 50 will be explained in detail later.

[0026] A sub-flow meter 56 and a sub-valve 58 are provided at each starting end of the multiple sub-circulation channels 50. The sub-flow meter 56 has a wireless communication function that transmits and receives signals using radio waves or infrared rays. Examples of wireless communication standards that can be used include Wi-Fi (registered trademark) and Bluetooth (registered trademark). The sub-flow meter 56 communicates with the controller 66 using this wireless communication function. The sub-valve 58 is provided at each starting end of the multiple sub-circulation channels 50 and serves as a valve for opening and closing the corresponding channel. Like the sub-flow meter 56, the sub-valve 58 also has a wireless communication function and is a remotely operable solenoid valve. Like the main valve 42, the sub-valve 58 may be a control valve capable of controlling the flow rate, pressure, or both. A sub-pump 54 is provided midway along the sub-circulation channels 50. The sub-pump 54 pumps the coolant along the sub-circulation channels 50. The sub-pump 54 is smaller and has lower output than the main pump 36.

[0027] As will be described in detail later, immediately after the die-casting machine 10 starts up, the sub-pump 54 is driven with the sub-valve 58 open. As a result, the coolant flows through the in-mold flow path 30, then flows into the sub-circulation flow path 50, and then returns to the in-mold flow path 30. In other words, immediately after the die-casting machine 10 starts up, the in-mold flow path 30 and the sub-circulation flow path 50 form a circulation flow path for the coolant. To maintain this circulation flow path, check valves 60 and 62 are provided near the confluence 52 of the outbound flow path 26 and the sub-circulation flow path 50. The first check valve 60 is provided on the outbound flow path 26, slightly upstream of the confluence 52. The first check valve 60 allows flow from upstream to downstream (i.e., flow from the main pump 36 to the mold 12) while prohibiting flow from downstream to upstream. The second check valve 62 is provided on the sub-circulation flow path 50, slightly upstream of the confluence 52. The second check valve 62 allows a flow from the sub-circulation flow path 50 toward the outward path 26 , but prohibits a flow from the outward path 26 toward the sub-circulation flow path 50 .

[0028] Although a portion of the main circulation flow path 22 passes through the work area Aw, the sub-circulation flow path 50 does not. In other words, the area around the die-casting machine 10, which handles high-temperature molten metal, is designated a non-working area An, where personnel are prohibited from entering, during die-casting. A safety fence 64 is located around the die-casting machine 10, separating the non-working area An from the work area Aw, where personnel are permitted to enter. The sub-circulation flow path 50, sub-flow meter 56, sub-valve 58, and sub-pump 54 are all located in the non-working area An, inside the safety fence 64. Meanwhile, a portion of the main circulation flow path 22, the main flow meter 40, and the main valve 42 are all located in the work area Aw. This allows workers direct access to the main flow meter 40 and main valve 42 during die-casting, allowing them to operate the main valve 42 and monitor the coolant flow rate as needed.

[0029] The controller 66 controls the operation of the die-casting machine 10. The controller 66 is physically a computer having a processor 67 and a memory 68. Although FIG. 1 illustrates the controller 66 as a single computer, the controller 66 may be configured as a plurality of physically separate controllers 66. The controller 66 controls the operation of the pumps 36, 54 and the valves 42, 58 according to the progress of die-casting and the detection results of the flow meters 40, 56. More specifically, immediately after the start-up of the die-casting machine 10, the controller 66 drives the pumps 36, 54 and the valves 42, 58 so that the coolant circulates through the sub-circulation flow path 50, and thereafter the coolant circulates without passing through the sub-circulation flow path 50, as will be described later.

[0030] Next, the reason for providing the sub-circulation flow path 50 will be explained. When performing die casting, the main pump 36 is driven to adjust the temperature of the mold 12 to a desired temperature. This sends coolant to the in-mold flow path 30. The temperature of the mold 12 is adjusted to a desired temperature by adjusting the flow rate of this coolant. For example, when injecting molten metal into the mold 12, the mold 12 must be adjusted to a temperature that allows the molten metal to flow smoothly in the cavity space while preventing the molten metal from burning onto the mold 12. On the other hand, after filling the mold 12 with molten metal, the mold 12 must be quickly cooled so that the molten metal quickly solidifies. Therefore, the controller 66 controls the main pump 36, the main valve 42, or both based on the flow rate measured by the main flow meter 40 so that a larger amount of coolant flows into the in-mold flow path 30 after filling the molten metal compared to before filling.

[0031] As described above, the main flow meter 40 and the main pump 36 are both located outside the safety fence 64 and away from the mold 12. In particular, in the monolithic casting method for large components known as megacast or gigacast, the die-casting machine 10 is very large, and the length of the main circulation channel 22 and the flow rate of the coolant to be circulated are both very large. Therefore, immediately after starting the die-casting machine 10, it takes a long time for the pressure of the main pump 36 to be transmitted to the in-mold flow channel 30, and a long time for the flow rate of the in-mold flow channel 30 to be measured by the main flow meter 40. As a result, without utilizing the sub-circulation channel 50, the response of the coolant flow rate control is poor immediately after starting the die-casting machine 10.

[0032] Therefore, in this example, as described above, a sub-circulation flow path 50 is provided that branches off from the return path 28 of the main circulation flow path 22 and returns to the outward path 26. As described above, the sub-circulation flow path 50 passes near the mold 12 without passing through the work area Aw. Therefore, the distance of the sub-circulation flow path 50 is significantly shorter than that of the main circulation flow path 22. Immediately after starting up the die-casting machine 10, the sub-pump 54 provided in this sub-circulation flow path 50 pumps the coolant, thereby quickly forming a flow of coolant passing through the in-mold flow path 30 and quickly cooling the mold 12.

[0033] More specifically, before the die-casting machine 10 is started, the main circulation flow path 22 and the sub-circulation flow path 50 are already filled with coolant. When the die-casting machine 10 is started in this state, the controller 66 drives both the main pump 36 and the sub-pump 54 with the main valve 42 and the sub-valve 58 open.

[0034] FIG. 2 illustrates the flow of coolant at this time. As shown in FIG. 2, in this case, the main pump 36 and the sub-pump 54 each pump coolant. However, because the main pump 36 is far from the in-mold flow path 30, it takes time for the output pressure of the main pump 36 to be transmitted to the in-mold flow path 30. On the other hand, because the sub-pump 54 is close to the in-mold flow path 30, the output pressure of the sub-pump 54 reaches the in-mold flow path 30 quickly. Therefore, immediately after the start of the die-casting machine 10, the coolant is quickly sent from the in-mold flow path 30 to the sub-circulation flow path 50 by the output pressure of the sub-pump 54 and then flows toward the outgoing path 26. The coolant that flows into the outgoing path 26 re-flows into the in-mold flow path 30 because backflow is prevented by the first check valve 60. In this way, by driving the sub-pump 54, a circulating flow between the sub-circulation flow path 50 and the in-mold flow path 30 is established quickly after the start of the die-casting machine 10, allowing cooling (or temperature control) of the mold 12 to begin early.

[0035] At this time, the flow rate of the cooling liquid flowing through the sub-circulation flow path 50 is quickly measured by a sub-flow meter 56 arranged near the mold 12. The measurement result of the sub-flow meter 56 is transmitted by wireless communication to a controller 66 located in the work area Aw. The controller 66 wirelessly changes the opening degree of the sub-valve 58 in accordance with the received flow rate of the cooling liquid.

[0036] Here, the sub-circulation path 50 is not provided with the heat exchanger 38, and the circulation path is also short. Therefore, if only the sub-circulation path 50 is used, the temperature of the circulating coolant will rise quickly. Therefore, after the first shot is completed, or when the temperature of the coolant flowing through the sub-circulation path 50 exceeds a reference value, the controller 66 closes the sub-valve 58 and stops driving the sub-pump 54. Figure 3 shows the flow of the coolant at this time.

[0037] 3, in this case, after flowing out of the in-mold flow path 30, the coolant flows through the return path 28 without flowing into the sub-circulation path 50. The coolant then flows from the return path 28 through the heat exchanger 38, the tank 24, the main pump 36, and the outward path 26, before re-flowing into the in-mold flow path 30. During this process, the coolant dissipates heat sufficiently. Therefore, even if shots are subsequently repeated, the mold 12 is sent to the in-mold flow path 30 in a sufficiently cooled state, and the mold 12 can be appropriately cooled.

[0038] As is clear from the above explanation, in this example, immediately after the die-casting machine 10 is started, the sub-circulation flow path 50 is opened and the sub-pump 54 is driven to form a flow that circulates through the sub-circulation flow path 50 and the in-mold flow path 30. As a result, even immediately after the die-casting machine 10 is started, the coolant can be sent to the in-mold flow path 30 quickly, thereby appropriately cooling the mold 12. In particular, in this example, the sub-circulation flow path 50 is configured not to pass through the work area Aw, which is distant from the die-casting machine 10, so the distance of the sub-circulation flow path 50 can be shortened. This effectively prevents a deterioration in the responsiveness of the coolant flow rate control.

[0039] When the mold 12 is removed from the die-casting machine 10 to replace it, the coolant in the in-mold flow path 30 can be purged while the main circulation path 22 and the sub-circulation path 50 remain filled with coolant. That is, when the mold 12 is removed from the die-casting machine 10, the inlet connector 32 and the outlet connector 34 are closed and the coolant in the in-mold flow path 30 is discharged to the outside. Then, after the in-mold flow path 30 is emptied, the mold 12 is removed from the die-casting machine 10. In this way, by adopting a configuration in which only the coolant in the in-mold flow path 30 is purged, it is possible to eliminate the time required to refill the main circulation path 22 and the sub-circulation path 50 with coolant, thereby shortening the time required to replace the mold 12.

[0040] Furthermore, all of the configurations described so far are merely examples, and other configurations may be changed as long as the configuration described in claim 1 is included. For example, in the above description, the sub-circulation flow path 50 and the sub-flow meter 56 are both arranged in the non-working area An, and a portion of the main circulation flow path 22 and the main flow meter 40 are arranged in the working area Aw. However, a portion of the sub-circulation flow path 50 or the sub-flow meter 56 may be arranged in the working area Aw, or the main circulation flow path 22 and the main flow meter 40 may both be arranged in the non-working area An.

[0041] In the above description, the sub-valve 58 is closed and the sub-pump 54 is stopped after the main pump 36 stabilizes its output of coolant. However, the sub-pump 54 may continue to be driven even after the sub-valve 58 is closed. For example, as shown in FIG. 4 , the mold 12 includes a component called a sleeve bush 14. The sleeve bush 14 is a substantially cylindrical component that surrounds the injection sleeve (not shown). The sleeve bush 14 needs to be cooled even during periods when cooling of the molded product is not required, such as during mold clamping and injection. To cool the sleeve bush 14, as shown in FIG. 4 , a local flow path 70 may be provided that branches off from the sub-circulation flow path 50, passes through the sleeve bush 14, and returns to the sub-circulation flow path 50. A third flow meter 72 and a third valve 74 are disposed in the local flow path 70 to measure the flow rate in the local flow path 70. The second check valve 62 is a fully closable solenoid valve.

[0042] When the flow rate of the main pump 36 stabilizes, the controller 66 closes the sub-valve 58 and the second check valve 62, and continues to drive the sub-pump 54 with the third valve 74 open. This establishes a flow of coolant circulating between the sub-circulation flow path 50 and the local flow path 70. This in turn cools the sleeve bush 14 by the sub-pump 54. Note that although the circulation path for cooling the sleeve bush 14 is short, the sleeve bush 14 has a smaller heat capacity than the entire mold 12, so even with this short circulation path, the sleeve bush 14 can be adequately cooled. [Explanation of symbols]

[0043] 10 die-casting machine, 12 mold, 14 sleeve bush, 20 cooling circuit, 22 main circulation flow path, 24 tank, 26 forward flow path, 28 return flow path, 30 in-mold flow path, 32 inlet connector, 34 outlet connector, 36 main pump, 38 heat exchanger, 40 main flow meter, 42 main valve, 50 sub-circulation flow path, 52 junction, 54 sub-pump, 56 sub-flow meter, 58 sub-valve, 60 first check valve, 62 second check valve, 64 safety fence, 66 controller, 67 processor, 68 memory, 70 local flow path, 72 third flow meter, 74 third valve.

Claims

1. a main circulation flow path through which a coolant for cooling the mold circulates; a main pump for supplying the coolant to the main circulation flow path; a sub-circulation flow path through which the coolant circulates, the sub-circulation flow path being shorter than the main circulation flow path; a sub-pump that sends the cooling liquid to the sub-circulation flow path; A die-casting machine comprising:

2. 2. The die casting machine according to claim 1, the main circulation flow path has an outgoing path that guides the cooling liquid toward the mold and a returning path that guides the cooling liquid that has exited the mold, the sub-circulation flow path branches off from the return path and merges with the outward path, the sub-pump is provided in the sub-circulation flow path and sends the coolant from the return path through the sub-circulation flow path to the outward path. A die-casting machine characterized by:

3. 3. The die casting machine according to claim 2, further comprising a first check valve and a second check valve disposed near a junction of the outward path and the sub-circulation path, the first check valve is disposed on the outbound path at a position upstream of the junction in a traveling direction of the outbound path, the second check valve is disposed in the sub-circulation flow path at a position upstream of the junction in the direction of travel of the return flow path. A die-casting machine characterized by:

4. 2. The die casting machine according to claim 1, The die-casting machine according to claim 1, wherein the output of the sub-pump is smaller than the output of the main pump.

5. 2. The die casting machine according to claim 1, further comprising: A safety fence separating the non-work area from the work area; a main flow meter disposed in the work area and configured to measure a flow rate of the main circulation flow path; a sub-flow meter disposed in the non-working area and configured to measure a flow rate of the sub-circulation flow path; a main circulation flow path having a portion passing through the working area; The sub-circulation flow path does not pass through the working area. A die-casting machine characterized by:

6. 2. The die casting machine according to claim 1, further comprising: Equipped with a controller, the controller causes the cooling liquid to flow through the sub-circulation flow path during a first shot after the start of the die-casting machine, and causes the cooling liquid to flow through the main circulation flow path during a second or subsequent shot, or when the temperature of the cooling liquid flowing through the sub-circulation flow path exceeds a reference value; A die-casting machine characterized by:

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