Molding machine

Abstract

This molding machine is provided with: an injection sleeve having a first molten metal pouring port through which molten metal is poured; a first plunger for injecting the molten metal; a first plunger driving mechanism for moving the first plunger forward and backward; a molten metal pouring sleeve having a second molten metal pouring port through which the molten metal is poured, and having one end communicating with the first molten metal pouring port; and a second plunger slidably fitted into the molten metal pouring sleeve. The molten metal pouring sleeve is provided with a molten metal storage part for storing the molten metal overflowing from the injection sleeve through the first molten metal pouring port in a state in which the second plunger is not moved during injection by the first plunger.

Description

molding machine

[0001] The present invention relates to a molding machine, and more particularly to a molding machine having multiple sleeves.

[0002] Conventionally, a molding machine equipped with a plurality of sleeves has been known, and such a molding machine is disclosed, for example, in Japanese Utility Model Application Laid-Open Publication No. 5-39742.

[0003] The above-mentioned Japanese Utility Model Application Publication No. 5-39742 discloses a casting apparatus including a plunger sleeve, a plunger tip, a feed pipe, and a feed tip. The plunger sleeve disclosed in the above-mentioned Japanese Utility Model Application Publication No. 5-39742 is provided with a molten metal outlet. The feed pipe disclosed in the above-mentioned Japanese Utility Model Application Publication No. 5-39742 is provided with a feed inlet. One opening of the feed pipe is connected to the molten metal outlet provided in the plunger sleeve. The casting apparatus disclosed in the above-mentioned Japanese Utility Model Application Publication No. 5-39742 is configured so that molten metal poured into the feed pipe via the feed inlet is supplied from the molten metal outlet into the plunger sleeve by the feed tip. The casting apparatus disclosed in the above-mentioned Japanese Utility Model Application Publication No. 5-39742 is also configured so that the molten metal outlet is blocked by the feed tip when molten metal is supplied from the feed pipe into the plunger sleeve.

[0004] Japanese Utility Model Application Laid-Open Publication No. 5-39742

[0005] However, in the casting apparatus (molding machine) disclosed in the above-mentioned Japanese Utility Model Application Laid-Open Publication No. 5-39742, molten metal is supplied from a supply port (second inlet) to a supply pipe (filling sleeve) and then fed to a plunger sleeve (injection sleeve) via a molten metal outlet (first inlet). Therefore, the amount of molten metal that can be poured into the injection sleeve depends on the volume of the inlet. Furthermore, because the second inlet provided on the inlet sleeve is open, when pouring molten metal from the inlet sleeve into the injection sleeve, only an amount of molten metal can be poured that will not overflow from the second inlet. Therefore, with the configuration disclosed in the above-mentioned Japanese Utility Model Application Laid-Open Publication No. 5-39742, the amount of molten metal that can be poured into the injection sleeve is reduced, which is disadvantageous in that the temperature of the molten metal in the injection sleeve is likely to drop. Therefore, the configuration disclosed in the above-mentioned Japanese Utility Model Application Laid-Open Publication No. 5-39742 has the problem that the quality of the molded product (product) deteriorates due to the decrease in the temperature of the molten metal in the injection sleeve.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a molding machine that can suppress a decrease in the quality of a molded article (product) caused by a decrease in the temperature of the molten metal in the injection sleeve.

[0007] In order to achieve the above object, one aspect of the present invention provides a molding machine comprising: a fixed die plate to which a mold is fixed; an injection sleeve which has a first inlet through which molten metal is poured and which has an injection port at one end and is held by the fixed die plate; a first plunger which is slidably fitted into the injection sleeve from the end opposite the injection port and which is moved back and forth within the injection sleeve to inject the molten metal poured into the injection sleeve; a first plunger drive mechanism which moves the first plunger back and forth within the injection sleeve; a molten metal pouring sleeve which has a second inlet through which molten metal is poured and which has one end connected to the first inlet; and a second plunger which is slidably fitted into the molten metal pouring sleeve from the other end of the sleeve, wherein the molten metal pouring sleeve is provided with a molten metal receiving section which receives molten metal that overflows from the injection sleeve via the first inlet when the second plunger is not being moved during injection by the first plunger.

[0008] As described above, a molding machine according to one aspect of the present invention includes a melt filling sleeve having a second pouring port through which the molten metal is poured and one end of which communicates with the first pouring port, and a second plunger slidably fitted within the melt filling sleeve. The melt filling sleeve is provided with a molten metal container that contains molten metal that overflows from the injection sleeve through the first pouring port when the second plunger is not moved during injection by the first plunger. This prevents the molten metal from overflowing from the melt filling sleeve, even when the filling rate of the molten metal poured into the injection sleeve is increased to the point where the molten metal overflows from the first pouring port. Therefore, since the filling rate of the molten metal in the injection sleeve can be increased, the degree of temperature decrease of the molten metal in the injection sleeve can be reduced. As a result, deterioration in the quality of the molded product (product) due to a decrease in the temperature of the molten metal in the injection sleeve can be prevented.

[0009] The molding machine according to the above aspect preferably further includes a molten metal detection unit that detects the molten metal in the injection sleeve, and a control unit that controls the start of forward movement of the first plunger during or immediately after the completion of the molten metal pouring based on the detection result of the molten metal detection unit. This configuration can shorten the time from the start of molten metal pouring to the start of injection of the molten metal by the first plunger, compared to a configuration in which the molten metal poured into the molten metal pouring sleeve is introduced into the injection sleeve by the plunger. As a result, a decrease in the temperature of the molten metal in the injection sleeve can be further suppressed. In this specification, "immediately after the completion of pouring" refers to the period from the completion of pouring of the molten metal until a predetermined time has elapsed. The predetermined time is preferably within 3 seconds after the completion of pouring of the molten metal. More preferably, the predetermined time is within 1 second after the completion of pouring of the molten metal.

[0010] In this case, the control unit is preferably configured to calculate the filling rate of the molten metal in the injection sleeve based on the detection result of the molten metal detection unit, and to control the first plunger drive mechanism to start advancing the first plunger during or immediately after the completion of pouring of the molten metal based on the calculated filling rate of the molten metal in the injection sleeve. This configuration allows the first plunger to start advancing when the filling rate of the molten metal in the injection sleeve exceeds a predetermined value, so that the first plunger can start advancing as soon as the amount of molten metal required to manufacture a molded item (product) is filled. As a result, the time from the start of pouring of the molten metal to the start of advancing the first plunger can be shortened, further suppressing a decrease in the temperature of the molten metal in the injection sleeve.

[0011] In the configuration in which the control unit controls the first plunger drive mechanism to start advancing the first plunger during or immediately after the completion of pouring of the molten metal based on the filling rate of the molten metal in the injection sleeve, the injection molding machine preferably further includes a discharge mechanism for discharging the molten metal solidified in the pouring sleeve, and the control unit is configured to control the discharge mechanism to discharge the molten metal solidified in the molten metal accommodation portion after injection of the molten metal. With this configuration, the molten metal solidified in the molten metal accommodation portion is discharged after injection of the molten metal, thereby preventing the molten metal from accumulating in the pouring sleeve. As a result, it is possible to prevent the molten metal accumulated in the pouring sleeve from mixing with newly poured molten metal, thereby preventing the quality of the molded article (product) from being reduced by the molten metal solidified in the molten metal accommodation portion.

[0012] In this case, the discharge mechanism preferably includes a second plunger and a second plunger drive mechanism that moves the second plunger back and forth, and the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so that the first plunger injects the molten metal without the second plunger blocking the second inlet of the molten metal sleeve. Here, even after the molten metal pouring operation is completed, some molten metal may flow into the molten metal pouring sleeve through the second inlet. In this case, if the second plunger closes the second inlet after the molten metal pouring operation is completed, solidified molten metal may accumulate around the second inlet. Therefore, by configuring the first plunger to inject the molten metal without blocking the second inlet as described above, accumulation of solidified molten metal around the second inlet can be suppressed, unlike a configuration in which the first plunger injects the molten metal while the second plunger blocks the second inlet. As a result, it is possible to prevent the solidified molten metal that has accumulated around the second pouring spout from mixing with the newly poured molten metal, thereby preventing the solidified molten metal from mixing with the molten metal around the second pouring spout and causing a deterioration in the quality of the molded product (product).

[0013] In the above-described configuration in which the discharge mechanism includes a second plunger and a second plunger drive mechanism, and the control unit injects the molten metal using the first plunger without blocking the second inlet of the inlet sleeve with the second plunger, the control unit is preferably configured to control the first plunger drive mechanism and the second plunger drive mechanism so that the first plunger injects the molten metal without the second plunger supporting the pressure during injection of the molten metal. In order for the second plunger to support the pressure during injection of the molten metal, the second plunger must be advanced to the vicinity of the first inlet after pouring the molten metal into the injection sleeve. In this case, the temperature of the molten metal in the injection sleeve decreases depending on the time elapsed until the second plunger's advancement is completed. Therefore, by configuring the second plunger not to support the pressure during injection of the molten metal as described above, the molten metal can be injected using the first plunger without advancing the second plunger. As a result, it is possible to prevent a decrease in the temperature of the molten metal in the injection sleeve, thereby preventing a decrease in the quality of the molded product.

[0014] In this case, the control unit is preferably configured to control the first plunger drive mechanism and the second plunger drive mechanism so that the first plunger injects the molten metal while the second plunger is positioned so that its tip is closer to the other end of the molten metal sleeve than the second inlet. This configuration prevents the second plunger from blocking the second inlet when the molten metal is injected by the first plunger. As a result, blocking the second inlet by the second plunger prevents solidified molten metal from accumulating around the second inlet.

[0015] In the above-described configuration in which the discharge mechanism includes a second plunger and a second plunger drive mechanism, and the control unit injects the molten metal using the first plunger without blocking the second inlet of the molten metal sleeve with the second plunger, preferably, the first plunger has a length that blocks the first inlet when positioned to inject the molten metal from the injection sleeve into the mold, and the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so that, after injection of the molten metal into the mold is completed, the first plunger is retracted to a position where the tip of the first plunger opens the first inlet, and then the second plunger discharges the molten metal solidified within the molten metal sleeve. Here, if the first plunger does not block the first inlet when the molten metal is injected into the mold, the molten metal that overflows into the molten metal sleeve will flow back into the injection sleeve. The molten metal that flows back into the injection sleeve solidifies behind the first plunger. In this case, it becomes difficult to discharge the molten metal that has solidified within the injection sleeve. Therefore, with the above-described configuration, when the molten metal is injected into the mold, the first pouring port is blocked by the first plunger, thereby preventing the molten metal overflowing into the pouring sleeve from flowing back into the injection sleeve. As a result, it is possible to prevent the molten metal overflowing into the pouring sleeve from flowing back into the injection sleeve and solidifying behind the first plunger inside the injection sleeve, thereby preventing the molten metal from solidifying in a position where it is difficult to discharge.

[0016] In a configuration in which the discharge mechanism includes a second plunger and a second plunger drive mechanism, and the control unit injects the molten metal using the first plunger without blocking the second inlet of the melt-filling sleeve with the second plunger, the second plunger preferably has a diameter long enough to ensure a predetermined gap between the outer circumferential surface of the second plunger and the inner circumferential surface of the melt-filling sleeve. A lubricant is sprayed into the injection sleeve to improve the sliding properties of the first plunger. The sprayed lubricant is burned by the poured molten metal, generating gas. Therefore, with the above configuration, the gas generated by the poured molten metal can be exhausted through the gap between the second plunger and the melt-filling sleeve. This prevents gas from being mixed into the molten metal injected into the mold, thereby preventing the formation of porosity (cavities) due to the gas mixed into the molten metal. As a result, deterioration in the quality of the molded product (product) due to porosity (cavities) can be prevented. Furthermore, since a predetermined distance is maintained between the second plunger and the pouring sleeve, it is possible to prevent the second plunger from causing galling inside the pouring sleeve.

[0017] In this case, preferably, the apparatus further includes an exhaust mechanism having an exhaust pipe communicating with the pouring sleeve for exhausting gas from within the pouring sleeve, the exhaust pipe communicating with the pouring sleeve at a position on the other end of the pouring sleeve closer to the retraction limit of the second plunger. This configuration allows the exhaust mechanism to efficiently exhaust gas from within the pouring sleeve via the exhaust pipe, thereby further preventing the formation of cavities (blobs) due to gas being mixed into the molten metal injected into the mold. As a result, deterioration in the quality of the molded article (product) due to cavities (blobs) can be further prevented.

[0018] In the configuration in which the control unit controls the start of forward movement of the first plunger during or immediately after the completion of pouring of the molten metal based on the detection result of the molten metal detection unit, preferably, the injection sleeve has a discharge hole opposite the first inlet for discharging solidified molten metal and further includes a discharge hole opening / closing mechanism for opening and closing the discharge hole, and the control unit is configured to control the discharge hole opening / closing mechanism to open the discharge hole when discharging the molten metal solidified within the molten metal pouring sleeve. With this configuration, since the discharge hole is located opposite the first inlet, the molten metal solidified within the molten metal pouring sleeve can be discharged through the discharge hole without using the first plunger. Therefore, for example, compared to a configuration in which the solidified molten metal once discharged into the injection sleeve is discharged from one end of the injection sleeve by the first plunger, the solidified molten metal can be more effectively prevented from remaining within the injection sleeve. As a result, it is possible to prevent the solidified molten metal remaining within the injection sleeve from being mixed into the molded product (product), thereby preventing a deterioration in the quality of the molded product (product).

[0019] In the configuration in which the control unit controls the discharge mechanism to discharge the solidified molten metal in the molten metal accommodation unit after injection of the molten metal, the discharge mechanism preferably includes an air cylinder that uses air to discharge the solidified molten metal in the pouring sleeve. This configuration makes it possible to discharge the solidified molten metal using air, which prevents the plunger from causing galling to the pouring sleeve, unlike configurations in which a plunger is used to discharge the molten metal in the pouring sleeve.

[0020] According to the present invention, as described above, it is possible to provide a molding machine that can suppress a decrease in the quality of a molded product (product) caused by a decrease in the temperature of the molten metal in the injection sleeve.

[0021] FIG. 1 is a diagram schematically illustrating the configuration of a molding machine according to a first embodiment. FIG. 2 is a block diagram illustrating a control device provided in the molding machine according to the first embodiment. FIG. 3 is a diagram illustrating a second pouring port provided in the pouring sleeve and a molten metal accommodating section according to the first embodiment. FIG. 4 is a diagram illustrating the initial positions of the first plunger and the second plunger according to the first embodiment. FIG. 5 is a diagram illustrating the position of the first plunger at the completion of injection and the length of the first plunger according to the first embodiment. FIG. 6 is an enlarged diagram illustrating the distance between the second plunger and the pouring sleeve according to the first embodiment. FIG. 7 is a diagram illustrating the diameter of the second plunger and the inner diameter of the pouring sleeve according to the first embodiment. FIG. 8 is a diagram illustrating the pouring and injection operations of the molding machine according to the first embodiment. FIG. 9 is a diagram illustrating the discharging operation of solidified molten metal of the molding machine according to the first embodiment. FIG. 10 is a flowchart illustrating the pouring process and injection process of the molding machine according to the first embodiment. FIG. 11 is a flowchart illustrating the discharging process of solidified molten metal of the molding machine according to the first embodiment. FIG. 1 is a diagram schematically illustrating the configuration of a molding machine according to a second embodiment. FIG. 2 is a block diagram illustrating a control device provided in the molding machine according to the second embodiment. FIG. 3 is a diagram schematically illustrating an exhaust operation by an exhaust mechanism provided in the molding machine according to the second embodiment. FIG. 4 is a flowchart illustrating an exhaust process during pouring and injection of molten metal in the molding machine according to the second embodiment. FIG. 5 is a diagram schematically illustrating the configuration of a molding machine according to a third embodiment. FIG. 6 is a block diagram illustrating a control device provided in the molding machine according to the third embodiment. FIG. 7 is a diagram schematically illustrating the configuration of a discharge hole opening and closing mechanism provided in the molding machine according to the third embodiment. FIG. 8 is a diagram schematically illustrating the operation of discharging solidified molten metal in the molding machine according to the third embodiment. FIG. 9 is a flowchart illustrating the discharge process of solidified molten metal in the molding machine according to the third embodiment. FIG. 10 is a diagram schematically illustrating the configuration of a molding machine according to a fourth embodiment. FIG. 11 is a block diagram illustrating a control device provided in the molding machine according to the fourth embodiment. FIG. 12 is a diagram schematically illustrating the operation of discharging solidified molten metal in the molding machine according to the fourth embodiment.10 is a flowchart for explaining a process for discharging solidified molten metal in a molding machine according to a fourth embodiment.

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0023] [First Embodiment] The configuration of a molding machine 100 according to a first embodiment will be described with reference to Figures 1 to 9. In the drawings, the Z direction is the up-down direction, with the upward direction of the Z direction being the Z1 direction and the downward direction of the Z direction being the Z2 direction. The X direction and the Y direction are two directions that are perpendicular to each other in a horizontal plane. The X1 direction of the X direction is the forward direction of a first plunger tip 110 (described later), and the X2 direction of the X direction is the backward direction of the first plunger tip 110. One of the Y directions is the Y1 direction, and the other is the Y2 direction.

[0024] (Configuration of molding machine) The molding machine 100 shown in FIG. 1 is configured to mold a die-cast product (not shown) by injecting a liquid metal material (molten metal M (see FIG. 8(B))) into a mold 102 (cavity C (hollow portion) that will become the product shape) that includes a fixed mold 102a and a movable mold 102b, and solidifying the molten metal M inside the mold 102. In other words, the molding machine 100 according to the first embodiment is a die-casting machine. The metal material to be molded is, for example, an aluminum alloy, a zinc alloy, a magnesium alloy, or the like.

[0025] As shown in FIG. 1, the molding machine 100 includes an injection unit 101, a mold clamping unit 103, an intermediate plate 104, a control unit 105, and a water heater 106.

[0026] The injection device 101 includes an injection sleeve 1, a first plunger 101a, a first plunger drive mechanism 101b, a first hydraulic circuit 101c, and a position sensor 101d. The injection device 101 is configured to supply molding material into a cavity C. The injection device 101 is configured to inject molten metal M into a mold 102 from the rear side (X2 direction side) of a fixed mold 102a.

[0027] The injection sleeve 1 has a cylindrical shape. The injection sleeve 1 has a first pouring gate 1a through which the molten metal M is poured. The injection sleeve 1 has an injection port 1c at one end 1b (X1 direction side). The injection sleeve 1 is held by a fixed die plate 103a. A first plunger 101a is slidably fitted into the injection sleeve 1 from an end 1d (X2 direction side) at the other end 1d. In the example shown in FIG. 1, the first pouring gate 1a is provided on the side 1e on the upper side (Z1 direction side) of the injection sleeve 1. In the example shown in FIG. 1, the first pouring gate 1a is provided on the injection port 1c side provided at one end 1b of the injection sleeve 1.

[0028] The first plunger 101a is slidably fitted into the injection sleeve 1 from an end 1d opposite to the injection port 1c, and is configured to be moved back and forth within the injection sleeve 1 to inject the molten metal M poured into the injection sleeve 1. In the first embodiment, the first plunger 101a includes a first plunger tip 110 and a first plunger rod 111.

[0029] The first plunger tip 110 is slidably disposed within the injection sleeve 1. The first plunger tip 110 is attached to one end (the end on the X1 direction side) of the first plunger rod 111. The first plunger rod 111 has a columnar shape extending along the X direction. The other end (the end on the X2 direction side) of the first plunger rod 111 is attached to the piston rod of the first plunger drive mechanism 101b. The first plunger tip 110 is configured to inject the molten metal M supplied to the injection sleeve 1 into the cavity C by being moved back and forth within the injection sleeve 1 by the first plunger drive mechanism 101b via the first plunger rod 111.

[0030] The first plunger drive mechanism 101b is configured to move the first plunger 101a back and forth within the injection sleeve 1. In the first embodiment, the first plunger drive mechanism 101b has a hydraulic cylinder (hydraulic cylinder) that operates by hydraulic pressure (oil pressure). The first plunger drive mechanism 101b is configured to reciprocate the first plunger 101a in the X direction by hydraulic pressure. As a result, the first plunger 101a (first plunger tip 110) is configured to press (inject) the molten metal M into the mold 102.

[0031] The first plunger drive mechanism 101b is connected to a first hydraulic circuit 101c and is configured to be operated by the first hydraulic circuit 101c. The position (X-direction position) of the first plunger tip 110 moved by the first plunger drive mechanism 101b is detected by a position sensor 101d.

[0032] The position sensor 101d is configured to detect the position of the first plunger tip 110 (the stroke amount of the first plunger drive mechanism 101b). The position sensor 101d is, for example, a stroke sensor, a magnetic or optical linear encoder, or a laser length measuring device.

[0033] The mold clamping device 103 is configured to hold a mold 102 in which a cavity C is formed. The mold clamping device 103 includes a fixed die plate 103a, a movable die plate 103b, tie bars 103c, and a mold clamping drive unit (not shown). The fixed die plate 103a is configured to hold the fixed mold 102a. The movable die plate 103b is configured to hold the movable mold 102b.

[0034] The tie bars 103c are a plurality of columnar members extending in the X direction. One end of each tie bar 103c is fixed to the frame, and the other end is fixed to the fixed die plate 103a. The tie bars 103c are bridged between the fixed die plate 103a and the movable die plate 103b, and the movable die plate 103b is slidably fitted to the tie bars 103c. The tie bars 103c have the function of holding the movable die plate 103b and guiding its movement in the X direction.

[0035] The mold clamping drive unit has a toggle mechanism and is configured to be driven by a motor to reciprocate the movable die plate 103b and the movable mold 102b in the X direction along the tie bars 103c, thereby enabling the mold clamping device 103 to clamp the mold 102 (the movable mold 102b and the fixed mold 102a).

[0036] The intermediate plate 104 is disposed between the fixed mold 102a and the fixed die plate 103a in the X direction. The intermediate plate 104 holds the molten metal pouring sleeve 2, which will be described later. The intermediate plate 104 is a plate-like member having a rectangular shape when viewed from the X direction. The size of the intermediate plate 104 in the Z direction is either approximately equal to that of the fixed mold 102a or is larger than that of the fixed mold 102a and smaller than that of the fixed die plate 103a. The size of the intermediate plate 104 in the Y direction is either approximately equal to that of the fixed mold 102a or is larger than that of the fixed mold 102a and smaller than that of the fixed die plate 103a. The intermediate plate 104 is formed, for example, from an iron material.

[0037] In the first embodiment, the molding machine 100 also includes a pouring sleeve 2. The molding machine 100 also includes a molten metal detector 3 (see FIG. 2 ) that detects the molten metal M in the pouring sleeve 2. The molding machine 100 also includes a discharge mechanism 4.

[0038] The pouring sleeve 2 is held by the intermediate plate 104. The pouring sleeve 2 is a sleeve for pouring the molten metal M into the molding machine 100. The pouring sleeve 2 has a cylindrical shape. The pouring sleeve 2 has a second pouring inlet 2a through which the molten metal M is poured. The pouring sleeve 2 is configured so that one end 2c communicates with the first pouring inlet 1a. In the example shown in FIG. 1, the pouring sleeve 2 communicates with the first pouring inlet 1a so that one end 2c faces downward (in the Z2 direction). That is, in the example shown in FIG. 1, the pouring sleeve 2 is provided on the injection sleeve 1 so as to extend in the vertical direction (in the Z direction).

[0039] The molten metal detection unit 3 is configured to detect the molten metal M in the injection sleeve 1. The molten metal detection unit 3 is configured, for example, to include any one or a combination of a current sensor, a temperature sensor, a pressure sensor, and an angle sensor that detects the angle of the ladle 106a. The molten metal detection unit 3 is configured to transmit a detection signal Ds (see FIG. 2) to the control device 105 when it detects the molten metal M in the pouring sleeve 2.

[0040] The discharge mechanism 4 is configured to discharge the molten metal Ma (see FIG. 9(A)) that has solidified inside the pouring sleeve 2. In the first embodiment, the discharge mechanism 4 includes a second plunger mechanism 5. The second plunger mechanism 5 has a second plunger 50 that is slidably fitted into the pouring sleeve 2 from the other end 2d of the pouring sleeve 2. The second plunger mechanism 5 also includes a second plunger drive mechanism 51 that moves the second plunger 50 forward and backward. The second plunger mechanism 5 is configured to move the second plunger 50 forward and backward by the second plunger drive mechanism 51. Details of the configuration in which the second plunger mechanism 5 moves the second plunger 50 forward and backward will be described later.

[0041] The second plunger 50 includes a second plunger tip 50a and a second plunger rod 50b. The second plunger tip 50a is slidably disposed within the pouring sleeve 2. The second plunger tip 50a is attached to one end (the end on the Z2 side) of the second plunger rod 50b. The second plunger rod 50b has a linear columnar shape. The other end (the end on the Z1 side) of the second plunger rod 50b is attached to a second plunger drive mechanism 51. The second plunger tip 50a is configured to be moved back and forth within the pouring sleeve 2 by the second plunger drive mechanism 51 via the second plunger rod 50b. Note that, in this specification, the forward and backward movement of the second plunger 50 may be referred to as the forward and backward movement of the second plunger tip 50a.

[0042] The second plunger drive mechanism 51 is connected to the second hydraulic circuit 52 and is configured to be operated by the second hydraulic circuit 52. The second plunger drive mechanism 51 is a hydraulic cylinder. The position (Z direction position) of the second plunger 50 moved by the second plunger drive mechanism 51 is detected by a position sensor 53.

[0043] The position sensor 53 is configured to detect the position of the second plunger tip 50a (the stroke amount of the second plunger drive mechanism 51). The position sensor 53 is, for example, a stroke sensor, a magnetic or optical linear encoder, or a laser length measuring device.

[0044] The control device 105 is configured to control the driving of each part of the molding machine 100 including the discharge mechanism 4 , the injection device 101 , and the mold clamping device 103 .

[0045] The melt supply device 106 includes a ladle 106a and an arm 106b that holds the ladle 106a. The melt supply device 106 is configured to draw molten metal M (see FIG. 8(B)) from the melting furnace 107 using the ladle 106a under the control of the control device 105, and pour the drawn molten metal M into the second pouring spout 2a.

[0046] (Control Device) As shown in FIG. 2, the control device 105 includes a control unit 105a, a storage unit 105b, and a display unit 105c.

[0047] Control unit 105a is configured to control second plunger mechanism 5, injection unit 101, mold clamping unit 103 (see FIG. 1), and molten metal supply unit 106. Control unit 105a is also configured to control molten metal supply unit 106 to pour molten metal M into second pouring gate 2a (see FIG. 1) of molding machine 100 (see FIG. 1). Control unit 105a is configured, for example, by a computer including a processor such as a CPU (Central Processing Unit) and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0048] The storage unit 105b stores various programs executed by the control unit 105a. The storage unit 105b includes a non-volatile recording medium such as a flash memory.

[0049] The display unit 105c includes a display medium such as a liquid crystal monitor, and is configured to display various information related to the molding machine 100 (see FIG. 1).

[0050] (Second pouring spout and molten metal accommodating portion) As shown in Figure 3, the second pouring spout 2a is provided on the side surface 2e of the melt pouring sleeve 2. Specifically, the second pouring spout 2a is provided on the side surface 2e on the X2 side of the melt pouring sleeve 2. The second pouring spout 2a is also provided with a molten metal passage 6 through which the molten metal M (see Figure 8(B)) flows when the molten metal M is poured by the ladle 106a. The molten metal passage 6 is provided on the melt pouring sleeve 2 so as to protrude in the X2 direction from the side surface 2e on the X2 side of the melt pouring sleeve 2.

[0051] In the first embodiment, the pouring sleeve 2 is provided with a molten metal accommodation portion 2b. The molten metal accommodation portion 2b is configured to accommodate the molten metal M that overflows from the injection sleeve 1 via the first pouring gate 1a when the second plunger 50 (see FIG. 1) is not being moved during injection by the first plunger 101a (see FIG. 1). As shown in FIG. 3, the molten metal accommodation portion 2b is provided in the pouring sleeve 2 at a position between the second pouring gate 2a and the first pouring gate 1a.

[0052] (Arrangement of First Plunger and Second Plunger at Initial Position) Next, the arrangement of the first plunger 101a at the initial position BP will be described with reference to Figure 4. The initial position BP is the position of the first plunger 101a when pouring the molten metal M (see Figure 8(B)) into the injection sleeve 1. The arrangement of the first plunger 101a also refers to the position of the tip 110a of the first plunger tip 110.

[0053] FIG. 4 is a schematic diagram of the first plunger 101a when it is positioned at the initial position BP. The initial position BP is the position of the first plunger 101a when the first plunger tip 110 is moved to the first inlet 1a. In the initial position BP, the tip 110a of the first plunger tip 110 is positioned at approximately the same position as the rear end of the first inlet 1a or slightly behind it (toward the end 1d (see FIG. 1) of the injection sleeve 1). The first plunger tip 110 is moved backward to the retracted position RP by the injection device 101 (see FIG. 2) under the control of the control unit 105a (see FIG. 2).

[0054] 4, the movable mold 102b is provided with a flow diverter 102c. As a result, when the mold is closed, a portion of a communication port 102d communicating with the injection sleeve 1 is blocked by the flow diverter 102c, narrowing the communication port 102d. Therefore, even when the molten metal M is poured into the injection sleeve 1, the molten metal M does not easily flow into the mold 102.

[0055] (Disposition of First Plunger at Completion of Injection) FIG. 5 is a schematic diagram showing the position of the first plunger 101a at the completion of injection.

[0056] As shown in FIG. 5, at the completion of injection, the first plunger 101a is positioned at injection position IP. The size W1 of the first plunger tip 110 in the X direction is such that the first plunger tip 110 closes the first inlet 1a when the tip 110a of the first plunger tip 110 is positioned at injection position IP. In other words, the first plunger 101a has a length that closes the first inlet 1a when the first plunger 101a is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102. The size W1 of the first plunger tip 110 in the X direction is, for example, greater than the distance from the rear end of the first inlet 1a to the fixed mold 102a.

[0057] (Gap Between Second Plunger and Melt Pouring Sleeve) Next, with reference to Figs. 6 and 7, the gap 60 between the second plunger 50 and the melt pouring sleeve 2 will be described.

[0058] 6, a predetermined gap 60 is provided between the outer peripheral surface 50d of the second plunger 50 and the inner peripheral surface 2f of the molten metal pouring sleeve 2. In the first embodiment, the gap 60 has a length G1 between the outer peripheral surface 50d of the second plunger tip 50a and the inner peripheral surface 2f of the molten metal pouring sleeve 2. The length G1 is, for example, 1 to 2 mm.

[0059] As shown in Figure 7, the second plunger 50 (see Figure 6) has a diameter D1 long enough to ensure a predetermined distance 60 between the outer peripheral surface 50d of the second plunger 50 and the inner peripheral surface 2f of the molten metal pouring sleeve 2. In other words, the gap (clearance) between the diameter D1 of the second plunger tip 50a and the inner diameter D2 of the molten metal pouring sleeve 2 is the predetermined distance 60. As shown in Figure 7, the predetermined distance 60 is a space (region) having a cylindrical shape when viewed from the Z direction.

[0060] As shown in Figure 6, the pouring sleeve 2 is provided with an exhaust port 2g. The exhaust port 2g is provided to exhaust gas generated when the molten metal M (see Figure 8(B)) is poured from the second pouring port 2a. The exhaust port 2g is provided on the pouring sleeve 2, closer to the other end 2d (see Figure 1) than the second plunger tip 50a. Therefore, in the first embodiment, gas generated during pouring flows through the gap 60 between the outer peripheral surface 50d of the second plunger tip 50a and the inner peripheral surface 2f of the pouring sleeve 2, and is exhausted via the exhaust port 2g.

[0061] (Pouring and Injecting Molten Metal) Next, the pouring and injection operations of the molten metal M (see FIG. 8B) will be described with reference to FIGS. 8A to 8F. The control unit 105a (see FIG. 2) is configured to execute the pouring and injection operations of the molten metal M by controlling the injection device 101 (see FIG. 2) and the second plunger mechanism 5 (see FIG. 2). Note that in the example shown in FIG. 8, for convenience, the insertion angle (the angle of the molten metal passage 6 relative to the molten metal pouring sleeve 2) is shown larger than that of the molten metal passage 6 shown in FIG. 3. However, in reality, the molten metal passage 6 communicates with the molten metal pouring sleeve 2 at the same insertion angle as in the example shown in FIG. 3. Note that in the following description, the insertion angle of the molten metal passage 6 will be the same as in the example shown in FIG. 3.

[0062] FIG. 8(A) is a schematic diagram of the first plunger tip 110 positioned at the initial position BP. FIG. 8(B) is a schematic diagram of the ladle 106a starting to pour molten metal M into the injection sleeve 1. FIG. 8(C) is a schematic diagram of the first plunger tip 110 being retracted while pouring molten metal M into the injection sleeve 1. FIG. 8(D) is a schematic diagram of the first plunger tip 110 starting to advance. FIG. 8(E) is a schematic diagram of the molten metal M overflowing from the first inlet 1a being accommodated in the molten metal accommodation section 2b. FIG. 8(F) is a schematic diagram of the injection completed by the injection device 101 (see FIG. 2). In the molding machine 100 (see FIG. 1), the molding operation of the die-cast product is performed in the order of FIGS. 8(A), 8(B), 8(C), 8(D), 8(E), and 8(F).

[0063] As shown in FIG. 8(A), when starting to pour the molten metal M (see FIG. 8(B)), the control unit 105a (see FIG. 2) controls the injection device 101 (see FIG. 2) to place the first plunger tip 110 at the initial position BP. The control unit 105a also controls the second plunger 50 to place the second plunger tip 50a at a position closer to the other end 2d (see FIG. 1) of the molten metal pouring sleeve 2 than the second pouring spout 2a. Note that when the first plunger tip 110 is placed at the initial position BP, the control unit 105a does not place the first plunger tip 110 at the initial position BP. Furthermore, when the second plunger 50 is placed closer to the other end 2d of the molten metal pouring sleeve 2 than the second pouring spout 2a, the control unit 105a does not place the second plunger 50 at a position closer to the other end 2d of the molten metal pouring sleeve 2 than the second pouring spout 2a.

[0064] As shown in FIG. 8(B), the control unit 105a (see FIG. 2) controls the melt supply device 106 (see FIG. 2) to start pouring the molten metal M with the ladle 106a. Specifically, the control unit 105a causes the ladle 106a to pour the molten metal M into the injection sleeve 1 through the molten metal passage 6 (see FIG. 3), the second pouring gate 2a (see FIG. 8(A)), and the first pouring gate 1a (see FIG. 8(A)). The molten metal M poured from the ladle 106a flows into the injection sleeve 1 through the molten metal passage 6, the second pouring gate 2a, and the first pouring gate 1a due to its own weight (gravity).

[0065] As shown in Figure 8 (C), the control unit 105a (see Figure 2) controls the injection device 101 (see Figure 2) and the melt supply device 106 (see Figure 2) to pour molten metal M into the injection sleeve 1 while retracting the first plunger tip 110.

[0066] Here, the control unit 105a according to the first embodiment controls the melt supply device 106 (see FIG. 1 ) to pour the molten metal M into the injection sleeve 1 so that the filling rate of the molten metal M poured into the injection sleeve 1 is high. A state in which the filling rate of the molten metal M is high means, for example, that the filling rate of the molten metal M in the injection sleeve 1 is 75% or more.

[0067] As shown in Fig. 8(D), the control unit 105a (see Fig. 2) is configured to perform control to start the advancement of the first plunger 101a during the pouring of the molten metal M or immediately after the completion of the pouring of the molten metal M, based on the detection result of the molten metal detection unit 3 (see Fig. 2). In the first embodiment, the control unit 105a is configured to perform control to start the advancement of the first plunger 101a during the pouring of the molten metal M or immediately after the completion of the pouring of the molten metal M, based on the detection signal Ds sent from the molten metal detection unit 3. Note that in this specification, the advancement and retraction of the first plunger 101a may be referred to as the advancement and retraction of the first plunger tip 110.

[0068] In the first embodiment, the control unit 105a is configured to calculate the filling rate of the molten metal M in the injection sleeve 1 based on the detection result of the molten metal detection unit 3. Furthermore, the control unit 105a is configured to control the first plunger drive mechanism 101b to start the forward movement of the first plunger 101a during the pouring of the molten metal M or immediately after the completion of the pouring of the molten metal M, based on the calculated filling rate of the molten metal M in the injection sleeve 1. The example shown in Figure 8 (D) illustrates a configuration in which the control unit 105a performs control to start the forward movement of the first plunger 101a during the pouring of the molten metal M.

[0069] The filling rate of the molten metal M can be calculated from the volume of the injection sleeve 1 and the amount of the poured molten metal M. The volume of the injection sleeve 1 can be calculated from the inner diameter and length of the injection sleeve 1 and the position of the first plunger 101a (the tip 110a of the first plunger tip 110). The amount of the molten metal M in the injection sleeve 1 can be obtained based on the detection results of the molten metal detection unit 3. The detection results of the molten metal detection unit 3, the inner diameter and length of the injection sleeve 1, and the filling rate of the molten metal M in the injection sleeve 1 may be stored in advance in the memory unit 105b as filling rate relationship information that is associated with each other in the form of a table, for example, and the control unit 105a may obtain the filling rate of the molten metal M in the injection sleeve 1 based on the detection results of the molten metal detection unit 3 and the filling rate relationship information stored in the memory unit 105b.

[0070] In addition, in the first embodiment, the control unit 105a is configured to control the first plunger drive mechanism 101b so as to start advancing the first plunger tip 110 when the filling rate of the molten metal M in the injection sleeve 1 exceeds 85%.

[0071] The phrase "pouring molten metal M" refers to a state in which the molten metal M poured from the ladle 106a flows through any of the molten metal passage 6 (see FIG. 3), the second pouring gate 2a (see FIG. 8A), the pouring sleeve 2, and the first pouring gate 1a (see FIG. 8A). Therefore, even after all of the molten metal M in the ladle 106a has been supplied to the molten metal passage 6, the state may still fall under the category of "pouring molten metal M."

[0072] Furthermore, "immediately after the completion of pouring of the molten metal M" refers to the period from the completion of pouring of the molten metal M until a predetermined time has elapsed. The predetermined time is preferably within 3 seconds from the completion of pouring of the molten metal M. More preferably, the predetermined time is within 1 second from the completion of pouring of the molten metal M. Furthermore, the control unit 105a determines that pouring of the molten metal M is complete when the angle of the ladle 106a reaches a predetermined angle or when the filling rate of the molten metal M in the injection sleeve 1 reaches a preset value.

[0073] Furthermore, if the filling rate of the molten metal M in the injection sleeve 1 is high, as shown in FIG. 8(E), when the first plunger tip 110 advances to the first inlet 1a, the molten metal M overflows from the injection sleeve 1. Therefore, in this embodiment, the molten metal M overflowing from the injection sleeve 1 is accommodated in the molten metal accommodation portion 2b. Note that if the first plunger 101a advances at a high speed or depending on the arrangement of the second inlet 2a in the Z direction, the molten metal M overflowing from the injection sleeve 1 may enter between the second plunger 50 and the molten metal inlet sleeve 2. In this case, the molten metal M solidifies behind the second plunger 50. Therefore, to prevent the molten metal M overflowing from the injection sleeve 1 from reaching the rear of the second plunger 50, the speed of the first plunger 101a is set low, or the second inlet 2a is positioned closer to the other end 2d (see FIG. 1) of the molten metal inlet sleeve 2.

[0074] 8(F), the control unit 105a (see FIG. 2) controls the injection device 101 (see FIG. 2) to further advance the first plunger 101a (first plunger tip 110), thereby injecting the molten metal M in the injection sleeve 1 into the mold 102 (see FIG. 1). That is, in the first embodiment, the control unit 105a is configured to control the first plunger drive mechanism 101b (see FIG. 1) and the second plunger drive mechanism 51 (see FIG. 2) so that the first plunger 101a injects the molten metal M without the second plunger 50 blocking the second pouring port 2a of the pouring sleeve 2. In other words, the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so as to inject the molten metal M by the first plunger 101a while ensuring a gas flow path between the first pouring port 1a (see Figure 8 (A)) and the exhaust port 2g (see Figure 6).

[0075] 8(F), the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M when the second plunger 50 is positioned so that the tip 50c of the second plunger 50 is closer to the other end 2d (see FIG. 1) of the molten metal inlet 2a than the second inlet 2a. That is, the control unit 105a is configured to control the injection of the molten metal M when the tip 50c of the second plunger 50 is positioned closer to the Z1 direction than the second inlet 2a. In other words, the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M when the second plunger 50 does not support the pressure during injection of the molten metal M.

[0076] After the injection by the injection device 101 is completed, the control unit 105a holds the first plunger 101a in a state in which the first plunger 101a applies a predetermined pressure to the molten metal M in the mold 102. Then, a molded item (product) is manufactured by solidifying the molten metal M in the mold 102. At this time, the temperature of the molten metal M contained in the molten metal containing portion 2b decreases and eventually solidifies.

[0077] (Discharge Operation of Solidified Molten Metal) Next, with reference to FIGS. 9(A) to 9(E), the discharge operation of the solidified molten metal Ma (see FIG. 9(A)) in the molten metal accommodation section 2b (see FIG. 9(A)) will be described. FIG. 9(A) is a schematic diagram of the state after the mold is opened and the molded product (product) is removed after the injection of the molten metal M according to FIG. 8(F). FIG. 9(B) is a schematic diagram of the state when the first plunger tip 110 is retracted rearward from the initial position BP (toward the end 1d of the injection sleeve 1). FIG. 9(C) is a schematic diagram of the state when the second plunger tip 50a is advanced into the injection sleeve 1. FIG. 9(D) is a schematic diagram of the state when the second plunger tip 50a is retracted into the molten metal pouring sleeve 2. FIG. 9(E) is a schematic diagram of the state when the solidified molten metal Ma is discharged by advancing the first plunger tip 110. In addition, retracting the second plunger tip 50a means moving the second plunger tip 50a within the pouring sleeve 2 toward the other end 2d (see Figure 1) side (Z1 direction side) of the second pouring port 2a.

[0078] As shown in Fig. 9(A), when the molded article (product) is removed, solidified molten metal Ma is formed in the molten metal accommodation portion 2b. Therefore, in the first embodiment, the control portion 105a (see Fig. 2) is configured to control the discharge mechanism 4 (see Fig. 2) so as to discharge the solidified molten metal Ma in the molten metal accommodation portion 2b after the injection of the molten metal M (see Fig. 8(B)). Specifically, the control portion 105a controls the injection device 101 (see Fig. 2) and the second plunger 50 to discharge the solidified molten metal Ma.

[0079] 9(B), the control unit 105a (see FIG. 2) is configured to control the first plunger drive mechanism 101b (see FIG. 1) so as to retract the first plunger 101a to a position where the tip 110a of the first plunger 101a opens the first inlet 1a after the injection of the molten metal M into the mold 102 (see FIG. 1) is completed. In other words, the control unit 105a controls the first plunger drive mechanism 101b so as to retract the tip 110a of the first plunger tip 110 to a position on the X2 direction side of the rear end of the first inlet 1a.

[0080] As shown in FIG. 9(C), the control unit 105a (see FIG. 2) is configured to control the second plunger drive mechanism 51 (see FIG. 2) so as to discharge the molten metal Ma solidified in the pouring sleeve 2 by the second plunger 50. As a result, the molten metal Ma solidified in the molten metal accommodation portion 2b (see FIG. 9(A)) is discharged into the injection sleeve 1. Note that a portion of the molten metal Ma solidified in the molten metal accommodation portion 2b may fall into the injection sleeve 1 due to its own weight (gravity) before being discharged by the second plunger 50. In the first embodiment, the control unit 105a controls the second plunger 50 so as to perform the discharge operation by the second plunger 50, regardless of whether the solidified molten metal Ma falls due to its own weight.

[0081] Next, as shown in Figure 9 (D), the control unit 105a (see Figure 2) controls the second plunger 50 to retract the second plunger tip 50a into the pouring sleeve 2. In the first embodiment, the control unit 105a retracts the second plunger 50 so that the tip 50c of the second plunger 50 is positioned further in the Z1 direction than the second pouring gate 2a.

[0082] 9(E), the control unit 105a (see FIG. 2) controls the injection device 101 (see FIG. 2) to move the first plunger tip 110 forward to the injection port 1c. This causes the solidified molten metal Ma in the injection sleeve 1 to be discharged from the injection sleeve 1. Thereafter, the control unit 105a controls the injection device 101 to move the first plunger tip 110 to the initial position BP.

[0083] In the first embodiment, the control unit 105a (see FIG. 2) discharges the molten metal Ma solidified in the molten metal accommodation unit 2b by performing the control shown in FIGS. 9(A) to 9(E). That is, as shown in FIGS. 9(C) and 9(D), the control unit 105a is configured to control the second plunger 50 to perform a discharge operation after the first plunger 101a has moved backward within the injection sleeve 1 and before the first plunger 101a has moved forward within the injection sleeve 1.

[0084] (Pouring process and injection process) Next, the pouring process and injection process of the molten metal M (see FIG. 8(B)) performed by the control unit 105a (see FIG. 2) will be described with reference to Fig. 10. Note that the example shown in Fig. 10 is a control that is started on the premise that the first plunger 101a (see Fig. 8(A)) is positioned at the initial position BP (see Fig. 8(A)) and the second plunger 50 (see Fig. 8(A)) is positioned at a position on the Z1 direction side of the second pouring gate 2a (see Fig. 8(A)).

[0085] In step S1, the control unit 105a starts pouring the molten metal by controlling the molten metal supply device 106 (see FIG. 2). At this time, the control unit 105a controls the injection device 101 (see FIG. 2) to pour the molten metal M into the injection sleeve 1 while retracting the first plunger 101a, as shown in FIG. 8(C).

[0086] In step S2, the control unit 105a determines whether the filling rate of the molten metal M poured into the injection sleeve 1 exceeds a predetermined filling rate. Specifically, the control unit 105a calculates the filling rate of the molten metal M in the injection sleeve 1 based on the detection signal Ds (see FIG. 2) transmitted from the molten metal detection unit 3 (see FIG. 2), and determines whether the calculated filling rate exceeds the predetermined filling rate. If the filling rate of the molten metal M in the injection sleeve 1 exceeds the predetermined filling rate, the process proceeds to step S3. If the filling rate of the molten metal M in the injection sleeve 1 does not exceed the predetermined filling rate, the process of step S2 is repeated.

[0087] In step S3, the control unit 105a controls the injection device 101 to advance the first plunger 101a to the injection position IP as shown in Fig. 8(F), thereby injecting the molten metal M in the injection sleeve 1 into the mold 102 (see Fig. 1). Then, the process is completed.

[0088] (Discharge Process of Solidified Molten Metal) Next, with reference to Fig. 11, a process in which the control unit 105a (see Fig. 2) discharges the solidified molten metal Ma (see Fig. 9A) in the molten metal accommodation portion 2b (see Fig. 9A) will be described. Note that this process is performed after the molded article (product) is removed from the mold 102 (see Fig. 1).

[0089] In step S10, the control unit 105a controls the injection device 101 (see Figure 2) to move the first plunger 101a backward (towards the end 1d of the injection sleeve 1) beyond the first inlet 1a, as shown in Figure 9 (B).

[0090] In step S11, the control unit 105a controls the second plunger mechanism 5 (see FIG. 2) to advance the second plunger 50 into the injection sleeve 1, as shown in FIG. 9C.

[0091] In step S12, the control unit 105a controls the second plunger mechanism 5 to move the second plunger 50 back into the pouring sleeve 2, as shown in FIG. 9(D).

[0092] In step S13, the control unit 105a controls the injection device 101 to move the first plunger 101a to the injection port 1c, as shown in Fig. 9(E) . As a result, the solidified molten metal Ma in the injection sleeve 1 is discharged from the injection sleeve 1. Thereafter, the process ends.

[0093] (Effects of First Embodiment) The effects of the first embodiment will be described.

[0094] In the first embodiment, as described above, the molding machine 100 includes a fixed die plate 103a to which the mold 102 is fixed, a first pouring port 1a through which the molten metal M is poured, an injection sleeve 1 having an injection port 1c at an end 1b on one side (the X1 direction side) and held by the fixed die plate 103a, a first plunger 101a that is slidably fitted into the injection sleeve 1 from an end 1d on the opposite side (the X2 direction side) from the injection port 1c and moves back and forth within the injection sleeve 1 to inject the molten metal M poured into the injection sleeve 1, and a first plunger 101b that is slidably fitted into the injection sleeve 1 from an end 1d on the opposite side (the X2 direction side) from the injection port 1c and moves back and forth within the injection sleeve 1. The injection sleeve 2 is provided with a first plunger drive mechanism 101b that moves the plunger 101a back and forth within the injection sleeve 1, a second inlet 2a through which the molten metal M is poured and one end 2c of which is connected to the first inlet 1a, and a second plunger 50 that is slidably fitted into the molten metal sleeve 2 from the other end 2d of the molten metal sleeve 2, and the molten metal sleeve 2 is provided with a molten metal accommodation section 2b that accommodates the molten metal M that overflows from the injection sleeve 1 through the first inlet 1a when the second plunger 50 is not moved during injection by the first plunger 101a.

[0095] As a result, even if the filling rate of the molten metal M poured into the injection sleeve 1 is increased to the point that the molten metal M overflows from the first pouring port 1a when the molten metal M is injected, by accommodating the molten metal M in the molten metal accommodating portion 2b, the molten metal M can be prevented from overflowing from the molten metal pouring sleeve 2. Therefore, since it is possible to increase the filling rate of the molten metal M in the injection sleeve 1, it is possible to reduce the degree to which the temperature of the molten metal M in the injection sleeve 1 drops. As a result, it is possible to prevent a decrease in the quality of the molded article (product) due to a drop in the temperature of the molten metal M in the injection sleeve 1.

[0096] As described above, the first embodiment further includes the molten metal detection unit 3 that detects the molten metal M in the injection sleeve 1, and the control unit 105a that controls the start of forward movement of the first plunger 101a during pouring of the molten metal M or immediately after the completion of pouring of the molten metal M based on the detection result of the molten metal detection unit 3. This makes it possible to shorten the time from the start of pouring of the molten metal M to the start of injection of the molten metal M by the first plunger 101a, compared to a configuration in which the molten metal M poured into the pouring sleeve 2 is introduced into the injection sleeve 1 by the plunger. As a result, it is possible to further suppress a decrease in the temperature of the molten metal M in the injection sleeve 1.

[0097] Furthermore, in the first embodiment, as described above, the filling rate of the molten metal M in the injection sleeve 1 is calculated based on the detection result of the molten metal detection unit 3, and the first plunger drive mechanism 101b is controlled to start advancing the first plunger 101a during pouring of the molten metal M or immediately after the completion of pouring of the molten metal M based on the calculated filling rate of the molten metal M in the injection sleeve 1. This makes it possible to start advancing the first plunger 101a when the filling rate of the molten metal M in the injection sleeve 1 exceeds a predetermined value, so that the first plunger 101a can start advancing as soon as the amount of molten metal M required to manufacture a molded item (product) is filled. As a result, it is possible to shorten the time from the start of pouring of the molten metal M to the start of advancing the first plunger 101a, thereby further suppressing a decrease in the temperature of the molten metal M in the injection sleeve 1.

[0098] Furthermore, as described above, the first embodiment further includes a discharge mechanism 4 that discharges the molten metal Ma solidified in the pouring sleeve 2, and the control unit 105a is configured to control the discharge mechanism 4 so as to discharge the molten metal Ma solidified in the molten metal accommodation portion 2b after injection of the molten metal M. This allows the molten metal Ma solidified in the molten metal accommodation portion 2b to be discharged after injection of the molten metal M, thereby preventing the solidified molten metal Ma from accumulating in the pouring sleeve 2. As a result, it is possible to prevent the solidified molten metal Ma accumulated in the pouring sleeve 2 from mixing with newly poured molten metal M, thereby preventing the quality of the molded article (product) from being reduced due to mixing of the molten metal Ma solidified in the molten metal accommodation portion 2b.

[0099] Furthermore, in the first embodiment, as described above, the discharge mechanism 4 includes the second plunger 50 and the second plunger drive mechanism 51 that moves the second plunger 50 back and forth, and the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M without the second plunger 50 blocking the second inlet 2a of the molten metal pouring sleeve 2. Here, even after the molten metal M pouring operation is complete, there may be molten metal M flowing into the molten metal pouring sleeve 2 through the second inlet 2a. In this case, if the second plunger 50 blocks the second inlet 2a after the molten metal M pouring operation is complete, solidified molten metal Ma may accumulate around the second inlet 2a. Therefore, as described above, by configuring the first plunger 101a to inject the molten metal M without blocking the second inlet 2a with the second plunger 50, it is possible to prevent the solidified molten metal Ma from accumulating around the second inlet 2a, unlike a configuration in which the first plunger 101a injects the molten metal M while the second plunger 50 is blocking the second inlet 2a. As a result, it is possible to prevent the solidified molten metal Ma that has accumulated around the second inlet 2a from mixing with the newly poured molten metal M, and therefore it is possible to prevent the solidified molten metal Ma from mixing with the molten metal around the second inlet 2a and degrading the quality of the molded article (product).

[0100] Furthermore, in the first embodiment, as described above, the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so as to inject the molten metal M by the first plunger 101a in a state in which the second plunger 50 does not support the pressure during injection of the molten metal M. Here, in order for the second plunger 50 to support the pressure during injection of the molten metal M, it is necessary to advance the second plunger 50 to the vicinity of the first inlet 1a after pouring the molten metal M into the injection sleeve 1. In this case, the temperature of the molten metal M in the injection sleeve 1 decreases depending on the time elapsed until the advancement of the second plunger 50 is completed. Therefore, by configuring the second plunger 50 not to support the pressure during injection of the molten metal M as described above, the molten metal M can be injected by the first plunger 101a without advancing the second plunger 50. As a result, it is possible to prevent a decrease in the temperature of the molten metal M in the injection sleeve 1, thereby preventing a deterioration in the quality of the molded article (product).

[0101] Furthermore, in the first embodiment, as described above, the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M with the second plunger 50 positioned so that the tip 50c of the second plunger 50 is closer to the end 1d of the molten metal inlet 2a than the second inlet 2a. This prevents the second plunger 50 from blocking the second inlet 2a when the molten metal M is injected by the first plunger 101a. As a result, blocking the second inlet 2a with the second plunger 50 prevents solidified molten metal Ma from accumulating around the second inlet 2a.

[0102] Furthermore, in the first embodiment, as described above, the first plunger 101a has a length W1 that closes the first inlet 1a when the first plunger 101a is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102, and the control unit 105a is configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that, after injection of the molten metal M into the mold 102 is completed, the first plunger 101a is retracted to a position where the tip 110a of the first plunger 101a opens the first inlet 1a, and then the second plunger 50 discharges the molten metal Ma that has solidified in the molten metal pouring sleeve 2. Here, if the first plunger 101a does not close the first inlet 1a when the molten metal M is injected into the mold 102, the molten metal M that has overflowed into the molten metal pouring sleeve 2 will flow back into the injection sleeve 1. The molten metal M that flows back into the injection sleeve 1 solidifies behind the first plunger 101a. In this case, it becomes difficult to discharge the solidified molten metal Ma inside the injection sleeve 1. Therefore, with the above-described configuration, when the molten metal M is injected into the mold 102, the first pouring port 1a is blocked by the first plunger 101a, thereby preventing the molten metal M that overflows into the molten metal pouring sleeve 2 from flowing back into the injection sleeve 1. As a result, it becomes possible to prevent the molten metal M that overflows into the molten metal pouring sleeve 2 from flowing back into the injection sleeve 1 and solidifying behind the first plunger 101a inside the injection sleeve 1, thereby preventing the molten metal M from solidifying at a position where it is difficult to discharge.

[0103] Furthermore, in the first embodiment, as described above, the second plunger 50 has a diameter D1 long enough to ensure a predetermined gap 60 between the outer peripheral surface 50d of the second plunger 50 and the inner peripheral surface 2f of the melt-feed sleeve 2. A lubricant is sprayed into the injection sleeve 1 to improve the sliding properties of the first plunger 101a. The sprayed lubricant is burned by the poured molten metal M, generating gas. Therefore, by configuring as described above, the gas generated by the poured molten metal M can be exhausted through the gap 60 between the second plunger 50 and the melt-feed sleeve 2. This prevents gas from being mixed into the molten metal M injected into the mold 102, thereby preventing the formation of voids (cavities) due to the gas mixed into the molten metal M. As a result, the quality of the molded product (product) can be prevented from being reduced due to the voids (cavities). Furthermore, since a predetermined gap 60 is secured between the second plunger 50 and the molten metal pouring sleeve 2, it is possible to prevent the second plunger 50 from causing galling inside the molten metal pouring sleeve 2.

[0104] Second Embodiment Next, a molding machine 200 (see FIG. 12) according to a second embodiment will be described with reference to FIGS. 12 to 15. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0105] As shown in Figure 12, the molding machine 200 according to the second embodiment differs from the molding machine 100 according to the first embodiment (see Figure 1) in that it is equipped with a control device 201 instead of the control device 105 (see Figure 1), and in that it further includes an exhaust mechanism 108.

[0106] As shown in FIG. 13, the control device 201 according to the second embodiment differs from the control device 105 according to the first embodiment (see FIG. 2) in that it includes a control unit 201a instead of the control unit 105a (see FIG. 2).

[0107] The control unit 201a according to the second embodiment is configured to exhaust gas generated when the molten metal M (see FIG. 8(B)) is poured into the pouring sleeve 2 (see FIG. 12) by controlling the exhaust mechanism 108. The control unit 201a is configured by a computer including, for example, a processor such as a CPU and memories such as a ROM and a RAM.

[0108] The gas generated when the molten metal M is poured into the pouring sleeve 2 is generated by the combustion of the lubricant sprayed into the injection sleeve 1 (see Figure 12) to improve the sliding properties of the first plunger 101a (see Figure 12) in the injection sleeve 1.

[0109] The exhaust mechanism 108 also has an exhaust pipe 108a that communicates with the pouring sleeve 2. The exhaust mechanism 108 also has an exhaust pump 108b. The exhaust pipe 108a is, for example, a metal pipe. The exhaust pump 108b is a pump that supplies negative pressure, and includes, for example, a rotary pump (oil rotary pump) or a diaphragm pump.

[0110] The exhaust mechanism 108 is configured to exhaust gas from the inside of the pouring sleeve 2, which is connected to the exhaust mechanism 108 via an exhaust pipe 108a, using an exhaust pump 108b.

[0111] 14, the exhaust mechanism 108 is in communication with the pouring sleeve 2 via an exhaust pipe 108a. Specifically, the exhaust pipe 108a is in communication with the pouring sleeve 2 on the other end 2d side of the second plunger 50 at the most retracted position. In other words, the exhaust pipe 108a is in communication with the pouring sleeve 2 on the Z1 side of the second plunger tip 50a.

[0112] The control unit 201a (see Figure 13) is configured to control the exhaust mechanism 108 to exhaust the gas generated within the injection sleeve 1 through the first inlet 1a, the predetermined gap 60 between the second plunger tip 50a and the injection sleeve 2, and the exhaust pipe 108a.

[0113] (Exhaust Process) Next, referring to Fig. 15, a process in which the control unit 201a (see Fig. 13) according to the second embodiment performs exhaust using the exhaust mechanism 108 (see Fig. 13) when pouring and injecting the molten metal M (see Fig. 8(B)) will be described. Note that processes similar to the pouring process and injection process of the molten metal M performed by the control unit 105a (see Fig. 2) according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0114] In step S1, control unit 201a controls water heater 106 (see FIG. 13) to start pouring water.

[0115] In step S4, the control unit 201a starts exhausting by controlling the exhaust mechanism 108. Note that the process of step S4 may be performed before the process of step S1.

[0116] Next, in steps S2 and S3, the control unit 201a controls the injection device 101 (see FIG. 13) to inject the molten metal M.

[0117] In step S5, the control unit 201a controls the exhaust mechanism 108 to end the exhaust, and then the process ends.

[0118] The other configurations of the second embodiment are similar to those of the first embodiment.

[0119] (Effects of the Second Embodiment) The effects of the second embodiment will be described.

[0120] As described above, the second embodiment further includes an exhaust mechanism 108 having an exhaust pipe 108a communicating with the pouring sleeve 2 and configured to exhaust gas from within the pouring sleeve 2, the exhaust pipe 108a communicating with the pouring sleeve 2 at a position closer to the end 1d of the pouring sleeve 2 than the maximum retraction position of the second plunger 50. This allows the exhaust mechanism 108 to efficiently exhaust gas from within the pouring sleeve 2 via the exhaust pipe 108a, thereby further preventing the formation of cavities (poisons) caused by gas being mixed into the molten metal M injected into the mold 102. As a result, deterioration in the quality of the molded article (product) due to cavities (poisons) can be further prevented.

[0121] The other effects of the second embodiment are the same as those of the first embodiment.

[0122] Third Embodiment Next, a molding machine 300 (see FIG. 16) according to a third embodiment will be described with reference to FIGS. 16 to 20. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0123] As shown in Figure 16, the molding machine 300 according to the third embodiment differs from the molding machine 100 according to the first embodiment (see Figure 1) in that it is equipped with a control device 301 instead of the control device 105 (see Figure 1), and in that it further comprises a discharge hole opening / closing mechanism 109.

[0124] As shown in FIG. 17, the control device 301 according to the third embodiment differs from the control device 105 according to the first embodiment (see FIG. 2) in that it includes a control unit 301a instead of the control unit 105a (see FIG. 2).

[0125] The discharge hole opening / closing mechanism 109 is configured to open and close the discharge hole 1i (see FIG. 18). The discharge hole opening / closing mechanism 109 includes a third plunger 109a, a third plunger drive mechanism 109b, and a housing portion 109c.

[0126] The third plunger 109a is a plunger for opening and closing the discharge hole 1i. The third plunger drive mechanism 109b is a mechanism for moving the third plunger 109a back and forth. The third plunger drive mechanism 109b is, for example, a hydraulic cylinder. The storage section 109c is configured to store the solidified molten metal Ma1 (see FIG. 19(A)) and the solidified molten metal Ma2 (see FIG. 19(A)).

[0127] The control unit 301a according to the third embodiment is configured to control the discharge hole opening / closing mechanism 109 so as to open the discharge hole 1i when discharging the molten metals Ma1 and Ma2 solidified in the pouring sleeve 2 (see FIG. 18 ). The control unit 301a is configured, for example, by a computer including a processor such as a CPU and memories such as a ROM and a RAM.

[0128] 18, the injection sleeve 1 according to the third embodiment has a discharge hole 1i for discharging the solidified molten metal Ma at a position opposite the first pouring gate 1a. The discharge hole 1i and the container section 109c are connected via the sleeve 7. The inner diameter W2 of the discharge hole 1i and the inner diameter W3 of the sleeve 7 are equal to each other.

[0129] The third plunger 109a also has a third plunger tip 109d and a third plunger rod 109e. The third plunger tip 109d is connected to the third plunger rod 109e. The third plunger rod 109e is connected to a third plunger drive mechanism 109b (see FIG. 17). The third plunger drive mechanism 109b is configured to be able to move the third plunger rod 109e back and forth in the direction (X direction) along the extension direction of the injection sleeve 1. The third plunger tip 109d is moved back and forth in the X direction as the third plunger rod 109e is moved back and forth in the X direction by the third plunger drive mechanism 109b.

[0130] The length W4 of the third plunger tip 109d is greater than the inner diameter W2 of the discharge hole 1i and the inner diameter W3 of the sleeve 7.

[0131] The accommodation portion 109c is provided with an opening 109f. The accommodation portion 109c is connected to the sleeve 7 via the opening 109f. Therefore, the first pouring gate 1a, the discharge hole 1i, and the opening 109f are in communication with each other via the injection sleeve 1 and the sleeve 7.

[0132] As shown in Figures 19(A) to 19(F), the control unit 301a (see Figure 17) is configured to discharge the solidified molten metal Ma1 and the solidified molten metal Ma2 by controlling the injection device 101 (see Figure 17), the second plunger mechanism 5 (see Figure 17), and the third plunger drive mechanism 109b (see Figure 17).

[0133] The solidified molten metal Ma1 is the molten metal solidified in the molten metal accommodation portion 2 b, similar to the solidified molten metal Ma according to the first embodiment (see FIG. 9A ). The solidified molten metal Ma2 is the molten metal solidified in the space between the first plunger tip 110 and the third plunger tip 109 d when the third plunger tip 109 d is positioned to block the discharge hole 1 i.

[0134] Figures 19(A), 19(B), 19(D), and 19(E) are similar to the control of the discharge operation of the solidified molten metal Ma (see Figures 9(A) to 9(D)) performed by the control unit 105a (see Figure 2) according to the first embodiment described above, and therefore detailed explanations will be omitted.

[0135] First, as shown in Figures 19(A) and 19(B), the control unit 301a (see Figure 17) controls the injection device 101 (see Figure 17) to move the first plunger tip 110 backward from the first pouring gate 1a.

[0136] 19C, the control unit 301a (see FIG. 17) controls the discharge hole opening / closing mechanism 109 (see FIG. 17) to open the discharge hole 1i. Specifically, the control unit 301a controls the third plunger drive mechanism 109b to retract the third plunger tip 109d to a position where the discharge hole 1i is opened.

[0137] 19(D) and 19(E), the control unit 301a (see FIG. 17) advances the second plunger 50 (see FIG. 17) into the injection sleeve 1, and then retracts it into the pouring sleeve 2. As a result, the molten metal Ma1 solidified in the molten metal accommodation portion 2b in the pouring sleeve 2 and the molten metal Ma2 solidified in the space between the first plunger tip 110 and the third plunger tip 109d are discharged into the accommodation portion 10c. The control unit 301a may advance the second plunger 50 into the sleeve 7.

[0138] Furthermore, a portion of the solidified molten metal Ma1 may fall into the accommodation portion 109c due to its own weight (gravity) before being discharged by the second plunger 50. Similarly, the solidified molten metal Ma2 may fall into the accommodation portion 109c due to its own weight (gravity) before being discharged by the second plunger 50. In the third embodiment, the control unit 301a controls the second plunger 50 so that the second plunger 50 performs the discharge operation, regardless of whether the solidified molten metal Ma1 and the solidified molten metal Ma2 fall due to their own weight.

[0139] 19(F), the control unit 301a (see FIG. 17) controls the third plunger drive mechanism 109b (see FIG. 17) to advance the third plunger tip 109d. At this time, the control unit 301a controls the third plunger tip 109d to advance to a position where the discharge hole 1i is closed by the third plunger tip 109d. Thereafter, as in the first embodiment, the control unit 301a advances the first plunger tip 110 to the initial position BP (see FIG. 4).

[0140] (Discharge Process of Solidified Molten Metal) Next, with reference to Fig. 20, a process of discharging the solidified molten metal Ma1 (see Fig. 19(A)) and the solidified molten metal Ma2 (see Fig. 19(A)) performed by the control unit 301a (see Fig. 17) according to the third embodiment will be described. Note that processes similar to the discharge process of the molten metal M performed by the control unit 105a (see Fig. 2) according to the first embodiment described above will be assigned the same reference numerals, and detailed description thereof will be omitted.

[0141] In step S14, the control unit 301a controls the injection device 101 (see FIG. 17) to move the first plunger 101a rearward beyond the first inlet 1a and the discharge hole 1i, as shown in FIG. 19(B). Specifically, the control unit 301a moves the first plunger tip 110 rearward beyond the first inlet 1a and the discharge hole 1i.

[0142] In step S15, the control unit 301a controls the third plunger drive mechanism 109b (see FIG. 17) to move the third plunger tip 109d backward from the discharge hole 1i, as shown in FIG. 19C. This opens the discharge hole 1i. Note that the process of step S15 may be performed before the process of step S14.

[0143] Next, in step S11, the control unit 301a controls the second plunger mechanism 5 (see FIG. 17) to advance the second plunger 50 and discharge the solidified molten metal Ma1 and the solidified molten metal Ma2 as shown in FIG. 19(D). Then, in step S12, the control unit 301a controls the second plunger mechanism 5 to retreat the second plunger 50 as shown in FIG. 19(E).

[0144] In step S16, the control unit 301a controls the third plunger drive mechanism 109b to move the third plunger tip 109d forward, as shown in Fig. 19(F). This closes the discharge hole 1i. Then, the process ends.

[0145] The other configurations of the third embodiment are similar to those of the first embodiment.

[0146] (Effects of the Third Embodiment) The effects of the third embodiment will be described.

[0147] In the third embodiment, as described above, the injection sleeve 1 has a discharge hole 1i, which is located opposite the first pouring gate 1a and which discharges the solidified molten metal Ma1 and the solidified molten metal Ma2, and further includes a discharge hole opening / closing mechanism 109 which opens and closes the discharge hole 1i. The control unit 301a is configured to control the discharge hole opening / closing mechanism 109 to open the discharge hole 1i when discharging the solidified molten metal Ma1 and the solidified molten metal Ma2 from the pouring sleeve 2. As a result, since the discharge hole 1i is located opposite the first pouring gate 1a, the molten metal Ma1 solidified in the pouring sleeve 2 can be discharged through the discharge hole 1i without using the first plunger 101a. Therefore, compared to a configuration in which the solidified molten metal Ma1 once discharged into the injection sleeve 1 is discharged from one end of the injection sleeve 1 by the first plunger 101a, it is possible to more effectively prevent the solidified molten metal Ma1 from remaining in the injection sleeve 1. As a result, it is possible to prevent the solidified molten metal Ma1 remaining in the injection sleeve 1 from being mixed into the molded product (product), thereby preventing a decrease in the quality of the molded product (product).

[0148] The other effects of the third embodiment are the same as those of the first embodiment.

[0149] 21 to 24, a molding machine 400 (see FIG. 21) according to a fourth embodiment will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0150] The molding machine 400 according to the fourth embodiment differs from the molding machine 100 according to the first embodiment (see FIG. 1) in that it has a control device 401 instead of the control device 105 (see FIG. 1) and a discharge mechanism 402 instead of the discharge mechanism 4 (see FIG. 1).

[0151] As shown in FIG. 21, the discharge mechanism 402 includes an air cylinder 8 that uses air to discharge the molten metal Ma (see FIG. 23(A)) that has solidified inside the pouring sleeve 2.

[0152] The air cylinder 8 includes an air supply pipe 8a, which is inserted into the molten metal pouring sleeve 2 from the other end 2d side (Z1 direction side) of the molten metal pouring sleeve 2.

[0153] As shown in FIG. 22, the control device 401 according to the fourth embodiment differs from the control device 105 according to the first embodiment (see FIG. 2) in that it includes a control unit 401a instead of the control unit 105a (see FIG. 2).

[0154] The control unit 401a is configured to control the air cylinder 8 to discharge the molten metal Ma (see FIG. 23A) solidified in the injection sleeve 1. The control unit 401a is configured by, for example, a computer including a processor such as a CPU and memories such as a ROM and a RAM.

[0155] As shown in FIG. 22, the air cylinder 8 further includes an air source 8b.

[0156] As shown in Figures 23(A) to 23(D), the control unit 401a (see Figure 22) is configured to discharge the solidified molten metal Ma by controlling the injection device 101 (see Figure 22) and the air cylinder 8 (see Figure 22).

[0157] Figures 23(A), 23(B), and 23(D) are similar to the control of the discharge operation of solidified molten metal Ma (see Figures 9(A), 9(B), and 9(E)) performed by the control unit 105a (see Figure 2) according to the first embodiment described above, and therefore detailed explanations will be omitted.

[0158] First, as shown in Figures 23(A) and 23(B), the control unit 401a (see Figure 22) controls the injection device 101 (see Figure 22) to move the first plunger tip 110 backward from the first pouring gate 1a.

[0159] 23(C), the control unit 401a (see FIG. 22) controls the air cylinder 8 to discharge the molten metal Ma that has solidified in the pouring sleeve 2 into the injection sleeve 1. Specifically, the control unit 401a supplies air from the air source 8b through the air supply pipe 8a into the pouring sleeve 2, thereby discharging the molten metal Ma that has solidified in the pouring sleeve 2 into the injection sleeve 1.

[0160] 23(D), the control unit 401a (see FIG. 22) controls the injection device 101 (see FIG. 22) to move the first plunger tip 110 forward to the injection port 1c, whereby the solidified molten metal Ma in the injection sleeve 1 is discharged from the injection sleeve 1.

[0161] (Discharge Process of Solidified Molten Metal) Next, with reference to Fig. 24, a process of discharging solidified molten metal Ma (see Fig. 23(A)) performed by the control unit 401a (see Fig. 22) according to the fourth embodiment will be described. Note that processes similar to those performed by the control unit 105a (see Fig. 2) according to the first embodiment described above will be denoted by the same reference numerals, and detailed description thereof will be omitted.

[0162] In step S10, the control unit 401a controls the injection device 101 (see FIG. 22) to move the first plunger tip 110 backward beyond the first pouring gate 1a, as shown in FIG. 23(B).

[0163] In step S17, the control unit 401a controls the air cylinder 8 (see FIG. 22) to supply air into the molten metal pouring sleeve 2, as shown in FIG. 23(C). As a result, the molten metal Ma solidified in the molten metal accommodating portion 2b (see FIG. 23(A)) is discharged into the injection sleeve 1.

[0164] In step S13, the control unit 401a controls the injection device 101 to move the first plunger tip 110 forward to the injection port 1c. Then, the process ends.

[0165] The other configurations of the fourth embodiment are similar to those of the first embodiment.

[0166] (Effects of Fourth Embodiment) The effects of the fourth embodiment will be described.

[0167] In the fourth embodiment, as described above, the discharge mechanism 402 includes the air cylinder 8 that uses air to discharge the molten metal Ma that has solidified inside the pouring sleeve 2. This makes it possible to use air to discharge the molten metal Ma after solidification, and therefore, unlike a configuration in which a plunger is used to discharge the molten metal M inside the pouring sleeve 2, it is possible to prevent the plunger from causing galling on the pouring sleeve 2.

[0168] The other effects of the fourth embodiment are the same as those of the first embodiment.

[0169] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above-mentioned embodiments, and further includes all modifications within the meaning and scope of the claims.

[0170] For example, in the first to fourth embodiments, the control unit 105a (201a, 301a, 401a) controls the start of forward movement of the first plunger 101a based on the detection results of the molten metal detection unit 3 during or immediately after the completion of pouring of the molten metal M. However, the present invention is not limited to this configuration. For example, in the present invention, the control unit may be configured to control the start of forward movement of the first plunger 101a based on the elapsed time since the start of pouring of the molten metal M. However, if the start of forward movement of the first plunger 101a is controlled based on the elapsed time since the start of pouring of the molten metal M, it becomes difficult to accurately determine whether the amount of molten metal M required for the molded article (product) has been poured into the injection sleeve 1. Therefore, it is preferable that the control unit be configured to control the start of forward movement of the first plunger 101a based on the detection results of the molten metal detection unit 3 during or immediately after the completion of pouring of the molten metal M.

[0171] Furthermore, in the first to fourth embodiments, an example was shown in which the control unit 105a (201a, 301a, 401a) calculates the filling rate of the molten metal M in the injection sleeve 1 and controls the start of forward movement of the first plunger 101a during or immediately after the completion of pouring of the molten metal M based on the calculated filling rate of the molten metal M in the injection sleeve 1. However, the present invention is not limited to this. For example, in the present invention, the control unit does not need to calculate the filling rate of the molten metal M in the injection sleeve 1. In this case, the control unit may be configured to control the start of forward movement of the first plunger 101a based on the elapsed time since the start of pouring of the molten metal M. However, if the control unit controls the start of forward movement of the first plunger 101a based on the elapsed time since the start of pouring of the molten metal M, it becomes difficult to accurately determine whether the amount of molten metal M required for the molded item (product) has been poured into the injection sleeve 1. Therefore, it is preferable that the control unit is configured to calculate the filling rate of the molten metal M in the injection sleeve 1 and, based on the calculated filling rate of the molten metal M in the injection sleeve 1, control the start of the forward movement of the first plunger 101a during the pouring of the molten metal M or immediately after the pouring of the molten metal M is completed.

[0172] Furthermore, in the first to fourth embodiments, an example of a configuration was described in which the control unit 105a (201a, 301a, 401a) controls the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M when the second plunger 50 does not support the pressure during injection of the molten metal M. However, the present invention is not limited to this. For example, in the present invention, the control unit may be configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M when the second plunger 50 supports the pressure during injection of the molten metal M. However, when the second plunger 50 supports the pressure during injection of the molten metal M, the temperature of the molten metal M poured into the injection sleeve 1 decreases due to the time required to drive the second plunger 50. Furthermore, when the second pouring gate 2a is blocked by the second plunger 50 (second plunger tip 50a), the molten metal M solidifies around the second pouring gate 2a, and the solidified molten metal Ma accumulates around the second pouring gate 2a. If the temperature of the molten metal M drops and the solidified molten metal Ma that has accumulated around the second pouring gate 2a gets mixed in, the quality of the molded product will deteriorate. Therefore, the control unit is preferably configured to control the first plunger drive mechanism 101b and the second plunger drive mechanism 51 so that the first plunger 101a injects the molten metal M when the second plunger 50 does not support the pressure during injection of the molten metal M.

[0173] Furthermore, in the first to fourth embodiments, the control unit 105a (201a, 301a, 401a) controls the first plunger 101a to inject the molten metal M with the second plunger 50 positioned so that the tip 50c of the second plunger 50 is closer to the other end 2d of the molten metal sleeve 2 than the second inlet 2a, but the present invention is not limited to this. For example, the control unit may be configured to control the first plunger 101a to inject the molten metal M with the second plunger 50 positioned so that the tip 50c of the second plunger tip 50a is closer to the one end 2c of the molten metal sleeve 2 (in the Z2 direction) than the rear end of the second inlet 2a. However, if the tip 50c of the second plunger 50 is positioned further in the Z2 direction than the rear end of the second inlet 2a, the second inlet 2a (or a portion of the second inlet 2a) is blocked by the second plunger 50 (second plunger tip 50a), causing the molten metal M to solidify around the second inlet 2a and accumulate around the second inlet 2a. If the solidified molten metal Ma accumulated around the second inlet 2a gets mixed in, the quality of the molded product will deteriorate. Therefore, it is preferable that the control unit be configured to control the injection of the molten metal M by the first plunger 101a with the second plunger 50 positioned so that the tip 50c of the second plunger 50 is closer to the other end 2d of the molten metal sleeve 2 than the second inlet 2a.

[0174] Furthermore, in the above first to fourth embodiments, an example of a configuration has been shown in which the first plunger 101a (first plunger tip 110) has a length W1 that closes the first inlet 1a when it is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102, but the present invention is not limited to this. For example, in the present invention, the first plunger 101a (first plunger tip 110) does not have to have the length W1 that closes the first inlet 1a when it is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102. However, if the first plunger 101a (first plunger tip 110) does not have a length W1 that closes the first inlet 1a when it is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102, the molten metal M that overflows into the molten metal accommodating portion 2b will flow back into the injection sleeve 1 and solidify at a position behind the first plunger tip 110 within the injection sleeve 1 when the molten metal M is injected into the mold 102. In this case, it becomes difficult to discharge the molten metal Ma that has solidified within the injection sleeve 1. Therefore, it is preferable that the first plunger 101a (first plunger tip 110) be configured to have a length W1 that closes the first inlet 1a when it is positioned at position IP where the molten metal M in the injection sleeve 1 is injected into the mold 102.

[0175] Furthermore, in the first to fourth embodiments, an example was shown in which the second plunger 50 (second plunger tip 50a) has a diameter D1 long enough to ensure a predetermined gap 60 between the outer peripheral surface 50d of the second plunger 50 and the inner peripheral surface 2f of the molten metal pouring sleeve 2. However, the present invention is not limited to this. For example, in the present invention, the diameter of the second plunger 50 (second plunger tip 50a) may be approximately the same as the inner diameter D2 of the molten metal pouring sleeve 2. However, if the diameter of the second plunger 50 (second plunger tip 50a) is approximately the same as the inner diameter D2 of the molten metal pouring sleeve 2, it becomes difficult to ensure a path for discharging gas generated during pouring of the molten metal M. Furthermore, if the diameter of the second plunger 50 (second plunger tip 50a) is approximately the same as the inner diameter D2 of the molten metal pouring sleeve 2, the second plunger 50 (second plunger tip 50a) may cause galling of the molten metal pouring sleeve 2. Therefore, it is preferable that the second plunger 50 (second plunger tip 50a) be configured to have a diameter D1 of a length that allows a predetermined gap 60 to be maintained between the outer peripheral surface 50d of the second plunger 50 and the inner peripheral surface 2f of the molten metal pouring sleeve 2.

[0176] In the first to fourth embodiments, the intermediate plate 104 holds the molten metal pouring sleeve 2, but the present invention is not limited to this. For example, in the present invention, the molten metal pouring sleeve 2 may be held by the fixed die plate 103a.

[0177] In the first to fourth embodiments, the control unit 105a (201a, 301a, 401a) controls the molten metal supply device 106 to pour the molten metal M from the second pouring port 2a, but the present invention is not limited to this. For example, in the present invention, the molten metal M may be poured from the second pouring port 2a by a pouring pipe connected to the molten metal furnace 107.

[0178] In addition, in the first to third embodiments, an example in which the second plunger drive mechanism 51 is a hydraulic cylinder has been described, but the present invention is not limited to this. In the present invention, for example, the second plunger drive mechanism 51 may be configured as a drive mechanism other than a hydraulic cylinder. For example, the second plunger drive mechanism 51 may be an electric cylinder.

[0179] Furthermore, in the above first to fourth embodiments, an example of a configuration in which the molten metal M is poured into the injection sleeve 1 while the first plunger 101a (first plunger tip 110) is retracted has been shown, but the present invention is not limited to this. In the present invention, the first plunger tip 110 does not need to be retracted when the molten metal M is poured into the injection sleeve 1.

[0180] Furthermore, in the first to fourth embodiments, examples have been shown in which the injection sleeve 1 has a cylindrical shape (a cylindrical shape), but the present invention is not limited to this. The injection sleeve 1 may have any shape (cross-sectional shape) as long as the first plunger tip 110 is slidable. Furthermore, the inner and outer shapes of the cross section of the injection sleeve 1 may be different. For example, the inner cross section of the injection sleeve 1 may be circular, and the outer cross section of the injection sleeve 1 may be rectangular.

[0181] Furthermore, in the first to third embodiments, an example was shown in which the pouring sleeve 2 has a cylindrical (cylindrical) shape, but the present invention is not limited to this. The pouring sleeve 2 may have any cross-sectional shape as long as the second plunger tip 50a is slidable. Furthermore, the inner and outer cross-sectional shapes of the pouring sleeve 2 may be different. For example, the inner cross-section of the pouring sleeve 2 may be circular and the outer cross-section of the pouring sleeve 2 may be rectangular.

[0182] Furthermore, the insertion angle of the molten metal passage 6 (the angle of the molten metal passage 6 relative to the pouring sleeve 2) shown in the first to fourth embodiments is merely illustrative, and the insertion angle of the molten metal passage 6 may be any angle.

[0183] Furthermore, in the first to fourth embodiments, the second pouring gate 2a is provided on the side surface 2e of the molten metal pouring sleeve 2 on the X2 direction side, but the present invention is not limited to this. For example, in the present invention, the second pouring gate 2a may be provided on the side surface of the molten metal pouring sleeve 2 on the Y direction side. In this case, the molten metal passage 6 may be provided so as to extend along the Y direction.

[0184] In addition, in the first to fourth embodiments, the molding machine 100 (200, 300, 400) is a die-casting machine, but the present invention is not limited to this. For example, in the present invention, the molding machine may be an injection molding machine that molds resin.

[0185] Although the first to third embodiments have been described as being different from one another, the present invention is not limited to this. For example, the first to third embodiments may be combined in any combination.

[0186] Furthermore, in the first to fourth embodiments, for convenience of explanation, the processing operation of the control unit 105a (201a, 301a, 401a) has been described using a flow-driven flowchart in which processing is performed in order according to a processing flow, but the present invention is not limited to this. In the present invention, the processing operation of the control unit 105a (201a, 301a, 401a) may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the processing may be performed completely event-driven, or may be performed in a combination of event-driven and flow-driven.

[0187] DESCRIPTION OF SYMBOLS 1 Injection sleeve 1a First pouring port 1b One end (one end of injection sleeve) 1c Injection port 1d Opposite end (end of injection sleeve opposite to injection port) 1i Discharge hole 2 Melt injection sleeve 2a Second pouring port 2b Molten metal accommodating section 2d Other end (other end of melt injection sleeve) 2f Inner peripheral surface (inner peripheral surface of melt injection sleeve) 3 Melt detection section 4, 402 Discharge mechanism 8 Air cylinder 50 Second plunger 50c Tip (tip of second plunger) 50d Outer peripheral surface (outer peripheral surface of second plunger) 51 Second plunger drive mechanism 60 Predetermined interval 100, 200, 300, 400 Molding machine 101a First plunger 101b First plunger drive mechanism 102 Mold 103a Fixed die plate 105a, 201a, 301a, 401a: Control unit 110a: Tip (tip of first plunger) M: Molten metal Ma, Ma1, Ma2: Solidified molten metal

Claims

a first plunger that is slidably fitted into the injection sleeve from an end opposite the injection port and that moves back and forth within the injection sleeve to inject the molten metal that has been poured into the injection sleeve; a first plunger drive mechanism that moves the first plunger back and forth within the injection sleeve; a second pouring sleeve that has a second pouring port through which molten metal is poured and that has one end connected to the first pouring port; and a second plunger that is slidably fitted into the injection sleeve from the other end of the sleeve, wherein the pouring sleeve is provided with a molten metal receiving section that receives molten metal that overflows from the injection sleeve via the first pouring port when the second plunger is not being moved during injection by the first plunger.

2. The molding machine according to claim 1, further comprising: a molten metal detection unit which detects the molten metal in the injection sleeve; and a control unit which performs control to start the forward movement of the first plunger during pouring of the molten metal or immediately after the completion of pouring of the molten metal based on the detection result of the molten metal detection unit.

3. The molding machine according to claim 2, wherein the control unit is configured to calculate a filling rate of the molten metal in the injection sleeve based on the detection result of the molten metal detection unit, and to control the first plunger drive mechanism to start advancing the first plunger during pouring of the molten metal or immediately after completion of pouring of the molten metal based on the calculated filling rate of the molten metal in the injection sleeve.

4. A molding machine as described in claim 3, further comprising a discharge mechanism for discharging molten metal solidified within the pouring sleeve, and the control unit is configured to control the discharge mechanism so as to discharge the molten metal solidified in the molten metal accommodating section after the molten metal is injected.

5. The molding machine described in claim 4, wherein the discharge mechanism includes the second plunger and a second plunger drive mechanism that moves the second plunger back and forth, and the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so that the first plunger injects molten metal without the second plunger blocking the second pouring port of the molten metal pouring sleeve.

6. A molding machine as described in claim 5, wherein the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so as to inject molten metal by the first plunger in a state in which the second plunger does not support the pressure during injection of the molten metal.

7. The molding machine described in claim 6, wherein the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so as to inject molten metal by the first plunger with the second plunger positioned so that the tip of the second plunger is located at a position closer to the other end of the molten metal pouring sleeve than the second pouring port.

8. The molding machine described in claim 5, wherein the first plunger has a length to close the first inlet when the first plunger is positioned to inject the molten metal in the injection sleeve into the mold, and the control unit is configured to control the first plunger drive mechanism and the second plunger drive mechanism so that, after injection of the molten metal into the mold is completed, the first plunger is retracted to a position where the tip of the first plunger opens the first inlet, and then the second plunger discharges the molten metal that has solidified in the molten metal inlet sleeve.

9. A molding machine as described in claim 5, wherein the second plunger has a diameter of a length that enables a predetermined distance to be secured between the outer peripheral surface of the second plunger and the inner peripheral surface of the pouring sleeve.

10. A molding machine as described in claim 9, further comprising an exhaust mechanism having an exhaust pipe communicating with the pouring sleeve and discharging gas from within the pouring sleeve, the exhaust pipe communicating with the pouring sleeve at a position on the other end side of the pouring sleeve relative to the retreat limit of the second plunger.

11. The molding machine described in claim 2, wherein the injection sleeve has a discharge hole for discharging solidified molten metal at a position opposite the first pouring port, and further comprises a discharge hole opening / closing mechanism for opening and closing the discharge hole, and the control unit is configured to control the discharge hole opening / closing mechanism so as to open the discharge hole when discharging solidified molten metal within the pouring sleeve.

12. The molding machine according to claim 4, wherein the discharge mechanism includes an air cylinder that uses air to discharge the molten metal that has solidified within the pouring sleeve.

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