Die-casting machine

Abstract

To provide a die cast machine for lifting an injection device and a C frame while keeping its horizontal state with simple constitution.SOLUTION: A die cast machine includes: a lifting cylinder for expanding / contracting in a vertical direction below an injection device, and thereby lifting an injection device and a C frame with respect to a mold clamping device; an accumulator which is arranged on a side opposite to the C frame so as to sandwich the lifting cylinder in a longitudinal direction, and supplies previously accumulated hydraulic oil to a head chamber; and a control device for controlling expansion / contraction of the lifting cylinder. The control device permits expansion / contraction of the lifting cylinder, when the pressure of the hydraulic oil accumulated in the accumulator is within an allowable range, and regulates expansion / contraction of the lifting cylinder, when the pressure of the hydraulic oil accumulated in the accumulator is out of the allowable range.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a die-casting machine that injects molten metal into a mold.

Background Art

[0002] Conventionally, there is known a die-casting machine including a clamping device that opens, closes, and clamps a fixed-side mold and a movable-side mold, an injection device that injects molten metal into a cavity formed inside the fixed-side mold and the movable-side mold clamped by the clamping device, and a C-frame having an open end side of a C shape connected to the clamping device so as to be able to move up and down and a closed end side connected to the injection device.

[0003] In such a die-casting machine, it is necessary to change the height of the injection device according to the mold to be used. Therefore, Patent Document 1 discloses a technique of raising and lowering the injection device with respect to the C-frame using a single lifting cylinder. Further, Patent Document 2 discloses a technique of raising and lowering the injection device and the C-frame with respect to the clamping device using a plurality of electric jacks.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When, as in Patent Document 1, the positions of the clamping device and the C-frame are fixed and only the injection device is raised and lowered, a centering operation is required every time the position of the injection device is changed. Therefore, from the viewpoint of simplifying the work, it is desirable to raise and lower the injection device and the C-frame while fixing the clamping device, as in Patent Document 2.

[0006] Furthermore, in the method using multiple electric jacks, as described in Patent Document 2, the number of parts increases, making the device more complex. On the other hand, in the method using a single lifting cylinder, as described in Patent Document 1, if the position where thrust is applied deviates significantly from the center of gravity, there is a problem in that the injection device and C-frame cannot be raised and lowered while maintaining a horizontal position.

[0007] The present invention was made to solve the problems of the prior art, and its purpose is to provide a technology for raising and lowering an injection device and a C-frame relative to a clamping device in a die-casting machine, while maintaining a horizontal position, with a simple configuration. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a die-casting machine comprising: a clamping device for opening, closing and clamping a fixed mold and a movable mold; an injection device for injecting molten metal into cavities formed inside the fixed mold and the movable mold clamped by the clamping device; and a C-frame whose open end is vertically movable to the clamping device and whose closed end is fixed to the injection device, wherein the machine comprises a lifting cylinder that extends and retracts vertically below the injection device to raise and lower the injection device and the C-frame relative to the clamping device. A molten metal supply device that changes its position to a supply position for supplying molten metal from a melting furnace, a pouring position for pouring molten metal into the injection device, and an intermediate position between the supply position and the pouring position. The injection device comprises a control device for controlling the extension and retraction of the lifting cylinder, and the injection device comprises a sleeve communicating with the cavity, a plunger that advances within the sleeve toward the cavity to supply molten metal in the sleeve to the cavity, an injection cylinder that advances the plunger when hydraulic fluid is supplied to the head chamber and retracts the plunger when hydraulic fluid is supplied to the rod chamber, and an accumulator positioned longitudinally on the opposite side of the C-frame from the lifting cylinder to supply pre-pressurized hydraulic fluid to the head chamber. The center of gravity of the injection device and the C-frame increases in the longitudinal direction from the lifting cylinder as the amount of hydraulic fluid in the accumulator increases, the hot water supply device is supported by the C-frame on the opposite side of the accumulator from the lifting cylinder in the longitudinal direction and the width direction perpendicular to the longitudinal direction, and when the die-casting machine is viewed in plan, the center of gravity of the hot water supply device in the hot water supply position is closer to the lifting cylinder in the longitudinal direction and protrudes to one side in the width direction than the center of gravity of the hot water supply device in the pouring position, and the center of gravity of the hot water supply device in the intermediate position is located between the center of gravity of the hot water supply device in the hot water supply position and the center of gravity of the hot water supply device in the pouring position in the longitudinal direction and the width direction. The control device is the accumulator The amount of hydraulic fluid inside within acceptable limits Furthermore, the hot water supply device is in the intermediate position At that time, the extension and retraction of the lifting cylinder is permitted, and the accumulator The amount of hydraulic fluid inside but outside the above tolerance range or the hot water supply device is in the pouring position or the hot water supply position The device is characterized by restricting the extension and retraction of the lifting cylinder in that state. [Effects of the Invention]

[0009] According to the present invention, the injection device and C-frame can be raised and lowered while maintaining a horizontal position with a simple configuration. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view of the die-casting machine according to this embodiment. [Figure 2] This is a side view of the injection unit and C-frame positioned at the top. [Figure 3] This is a side view of the injection unit and C-frame positioned at the bottom. [Figure 4] This is a plan view of the injection unit and C-frame. [Figure 5] This diagram shows the orientation of the water heater. [Figure 6] This is a view of the positioning mechanism from the longitudinal direction. [Figure 7] This is a view of the positioning mechanism from the width direction. [Figure 8] This is a hardware configuration diagram of a die-casting machine. [Figure 9] This is a flowchart of the lifting and lowering control process. [Modes for carrying out the invention]

[0011] Figure 1 is a side view of the die-casting machine 10 according to this embodiment. The die-casting machine 10 manufactures molded products by injecting molten metal into a mold. As shown in Figure 1, the die-casting machine 10 mainly comprises a mold clamping device 20 and an injection device 30.

[0012] The clamping device 20 opens and closes and clamps the mold 21. Specifically, the clamping device 20 mainly includes a fixed die plate 23 that supports the fixed-side mold 22 and a movable die plate 25 that supports the movable-side mold 24. The fixed-side mold 22 and the movable-side mold 24 are supported so as to face each other in the left-right direction (horizontal direction) of the die-casting machine 10.

[0013] The movable die plate 25 moves in the left-right direction along the tie bar 28 when the driving force of the mold opening / closing cylinder 26 is transmitted through the toggle link mechanism 27. When the movable die plate 25 moves to the left, the fixed-side mold 22 and the movable-side mold 24 are separated (mold opening). On the other hand, when the movable die plate 25 moves to the right, the fixed-side mold 22 and the movable-side mold 24 come into contact (mold closing). Then, when further pressure is applied in the direction of moving the movable die plate 25 to the right, the fixed-side mold 22 and the movable-side mold 24 are clamped.

[0014] The injection device 30 injects molten metal into the clamped mold 21. The injection device 30 mainly includes an injection sleeve 31, a plunger 32, an injection cylinder 33, and an accumulator 34 (see FIGS. 2 and 3). The injection device 30 according to the present embodiment is arranged at a distance in the horizontal direction (to the right of the clamping device 20) from the clamping device 20.

[0015] The injection sleeve 31 is a cylindrical member attached to the fixed die plate 23. The tip of the injection sleeve 31 communicates with the internal space of the clamped mold 21 (hereinafter referred to as "cavity"). Further, the injection sleeve 31 stores the molten metal supplied by the hot water supply device 40 (see FIGS. 2 to 4).

[0016] The plunger 32 is housed in the injection sleeve 31 so as to be able to advance and retreat. When the plunger 32 advances, the molten metal stored in the injection sleeve 31 is supplied to the cavity. On the other hand, when the plunger 32 retreats, a space for storing the molten metal supplied from the ladle 41 is formed in the injection sleeve 31.

[0017] The injection cylinder 33 moves the plunger 32 forward and backward by expanding and contracting as hydraulic fluid is supplied and discharged (hereinafter referred to as "supply and discharge"). The injection cylinder 33 expands when hydraulic fluid is supplied to the head chamber and discharged from the rod chamber. This causes the plunger 32 to move forward within the injection sleeve 31. On the other hand, the injection cylinder 33 contracts when hydraulic fluid is supplied to the rod chamber and discharged from the head chamber. This causes the plunger 32 to retract within the injection sleeve 31.

[0018] The accumulator 34 is located in the longitudinal direction of the die-casting machine 10, on the opposite side of the lifting cylinder 51 from the hot water supply device 40 (in other words, the C-frame 12). The accumulator 34 stores (accumulates) the hydraulic fluid in a compressed state and supplies the compressed hydraulic fluid to the head chamber of the injection cylinder 33. More specifically, the accumulator 34 stores the hydraulic fluid that has been pumped from a hydraulic pump (not shown). The accumulator 34 also supplies the stored hydraulic fluid to the head chamber of the injection cylinder 33 according to the control of the control device 60 (see Figure 8), which will be described later. The pressure of the hydraulic fluid stored in the accumulator 34 is detected by a pressure sensor 35 (see Figure 8). The pressure sensor 35 detects the pressure of the hydraulic fluid stored in the accumulator 34 and outputs a pressure signal indicating the detected pressure to the control device 60.

[0019] Furthermore, the die-casting machine 10 is equipped with a base 11. The clamping device 20 and the injection device 30 are arranged opposite each other on the base 11. The opposing directions of the clamping device 20 and the injection device 30, the direction of movement of the movable die plate 25, and the forward and backward directions of the plunger 32 coincide with the "longitudinal direction" of the die-casting machine 10. On the other hand, in the horizontal direction, the shorter direction perpendicular to the longitudinal direction is referred to as the "width direction" of the die-casting machine 10.

[0020] Furthermore, the die-casting machine 10 is equipped with a C-frame 12. The C-frame 12 has a C-shape (or arc shape) when viewed from the side. The C-frame 12 is supported by a base 11. The C-frame 12 is also positioned between the clamping device 20 and the injection device 30 in the longitudinal direction of the die-casting machine 10.

[0021] The open end of the C-frame 12 is connected to the clamping device 20 (more specifically, the fixed die plate 23). The C-frame 12 is configured to be vertically movable relative to the clamping device 20. Furthermore, the closed end of the C-frame 12 is fixed to the injection device 30. The injection device 30 and the C-frame 12 move vertically together relative to the clamping device 20 by the extension and retraction of the lifting cylinder 51 (see Figure 2), which will be described later.

[0022] Figure 2 is a side view of the injection device 30 and C-frame 12 positioned in the upper position. Figure 3 is a side view of the injection device 30 and C-frame 12 positioned in the lower position. Figure 4 is a top view of the injection device 30 and C-frame 12. Figure 5 shows the orientation of the hot water supply device 40. As shown in Figures 2 to 4, the die-casting machine 10 further comprises a hot water supply device 40 and a lifting device 50.

[0023] The molten metal supply device 40 scoops up molten metal from the melting furnace M and supplies it to the injection device 30 (more specifically, the injection sleeve 31). As shown in Figure 4, the melting furnace M is located on one side (the front side) in the width direction of the die casting machine 10.

[0024] The hot water supply device 40 is located in the longitudinal direction of the die-casting machine 10, on the opposite side of the accumulator 34, with the lifting cylinder 51 in between. The hot water supply device 40 is also supported by the C-frame 12. The hot water supply device 40 mainly comprises a ladle 41, a link mechanism 42 for moving the ladle 41 between the melting furnace M and the injection sleeve 31, a motor 43 for operating the link mechanism 42, and a posture sensor 44 (see Figure 8). The hot water supply device 40 changes its posture between the pouring posture shown in Figure 5(A), the hot water supply posture shown in Figure 5(D), and the intermediate postures shown in Figures 5(B) and 5(C).

[0025] The pouring position shown in Figure 5(A) is the position of the molten metal supply device 40 when pouring molten metal from the ladle 41 to the injection sleeve 31. The molten metal supply position shown in Figure 5(D) is the position of the molten metal supply device 40 when supplying molten metal from the melting furnace M to the ladle 41. The intermediate positions shown in Figures 5(B) and 5(C) are the positions of the molten metal supply device 40 between the pouring position and the molten metal supply position. In other words, the molten metal supply device 40 changes its position from one of the pouring position and the molten metal supply position to the other via the intermediate position. The position sensor 44 detects the position of the molten metal supply device 40 and outputs a position signal indicating the detected position to the control device 60.

[0026] As shown in Figure 4, when the die-casting machine 10 is viewed from above, the center of gravity of the hot water supply device 40 moves along the imaginary line L, indicated by the dashed line. The imaginary line L extends linearly, jutting out to one side from the center of the die-casting machine 10 in the width direction (shown by the dashed line in Figure 4) as it approaches the injection device 30 (more specifically, the lifting cylinder 51) in the longitudinal direction. In other words, the imaginary line L extends linearly, approaching the center of the die-casting machine 10 in the width direction as it moves away from the lifting cylinder 51 in the longitudinal direction.

[0027] Figure 4 illustrates the center of gravity G1 of the hot water supply device 40 in the pouring position shown in Figure 5(A), the center of gravity G2 of the hot water supply device 40 in the hot water supply position shown in Figure 5(D), the center of gravity G3 of the hot water supply device 40 in the intermediate position shown in Figure 5(B), and the center of gravity G4 of the hot water supply device 40 in the intermediate position shown in Figure 5(C). Specifically, the center of gravity G2 is closer to the lifting cylinder 51 in the longitudinal direction and protrudes to one side in the width direction compared to the center of gravity G1. Furthermore, the center of gravity G3 and G4 are located between the center of gravity G1 and G4 in the longitudinal and width directions.

[0028] The lifting device 50 raises and lowers the injection device 30 and the C-frame 12 relative to the clamping device 20 between the upper position shown in Figure 2 and the lower position shown in Figure 3. The lower position is below the upper position. This switches the communication position of the injection sleeve 31 with respect to the mold 21 in the vertical direction. The lifting device 50 mainly comprises, for example, a lifting cylinder 51 and a pair of positioning mechanisms 52A and 52B.

[0029] The lifting cylinder 51 is located below the injection unit 30 and the C-frame 12. The lifting cylinder 51 is positioned between the accumulator 34 and the hot water supply unit 40 in the longitudinal direction, and at the center of the die-casting machine 10 in the width direction. The lifting cylinder 51 extends and retracts in response to the supply of hydraulic fluid from the hydraulic pump, thereby raising and lowering the injection unit 30 and the C-frame 12 relative to the clamping device 20.

[0030] As shown in Figure 4, in the longitudinal direction of the die-casting machine 10, the center of gravity positions G1 to G4 of the hot water supply device 40 and the center of gravity position G5 of the injection device 30 and C-frame 12 are located on opposite sides of the point of application P (i.e., the lifting cylinder 51) where the lifting cylinder 51 applies thrust to the injection device 30 and C-frame 12. The center of gravity position G5 moves in the longitudinal direction due to the pressure of the hydraulic fluid stored in the accumulator 34 (in other words, the amount of hydraulic fluid in the accumulator 34). More specifically, the center of gravity position G5 moves further in the longitudinal direction from the lifting cylinder 51 as the pressure of the hydraulic fluid stored in the accumulator 34 increases (in other words, as the amount of hydraulic fluid in the accumulator 34 increases).

[0031] Furthermore, the center of gravity G5 of the injection device 30 and the C-frame 12 is offset to the other side (rear side) of the center of the die-casting machine 10 in the width direction. In other words, the center of gravity G1 to G4 of the hot water supply device 40 and the center of gravity G5 of the injection device 30 and the C-frame 12 are located on opposite sides in the width direction, with the center of the die-casting machine 10 (i.e., the lifting cylinder 51) in between. In other words, the point of application P where the lifting cylinder 51 applies thrust to the injection device 30 and the C-frame 12 is located between the center of gravity G1 to G4 and the center of gravity G5 in both the longitudinal and width directions.

[0032] The pair of positioning mechanisms 52A and 52B are located below the injection device 30 and the C-frame 12. The pair of positioning mechanisms 52A and 52B are also located on both sides of the vertical cylinder 51 in the longitudinal direction. The pair of positioning mechanisms 52A and 52B position the injection device 30 and the C-frame 12 at the upper position shown in Figure 2 and the lower position shown in Figure 3, respectively.

[0033] Figure 6 is a view of the positioning mechanism 52A from the longitudinal direction. Figure 7 is a view of the positioning mechanism 52A from the width direction. Since the configuration of positioning mechanisms 52A and 52B is the same, the positioning mechanism 52A will be described in detail below. As shown in Figures 6 and 7, the positioning mechanism 52A mainly comprises a plurality of spacer rods 53A, a stand 54A, a plurality of upper position stoppers 55A, and a plurality of lower position stoppers 56A.

[0034] The spacer rod 53A is a long, rod-shaped member. The spacer rod 53A extends downward from the lower surface of the injection device 30. Furthermore, multiple spacer rods 53A are arranged at predetermined intervals in the longitudinal and widthwise directions. The spacer rod 53A moves up and down together with the injection device 30 and the C-frame 12.

[0035] The stand 54A is a plate-shaped member that extends horizontally. The stand 54A is fixed below the injection device 30 and the C-frame 12. Furthermore, the stand 54A has a through hole 57A that penetrates in the thickness direction (vertical direction) at a position facing the spacer rod 53A in the vertical direction.

[0036] As shown in Figures 6(A) and 7(A), when the lifting cylinder 51 extends and the injection device 30 and C-frame 12 rise, the spacer rod 53A is removed from the through hole 57A, and the lower end of the spacer rod 53A is positioned above the upper surface of the stand 54A. Also, as shown in Figures 6(B) and 7(B), when the lifting cylinder 51 retracts and the injection device 30 and C-frame 12 descend, the spacer rod 53A enters the through hole 57A.

[0037] The upper position stopper 55A is supported on the upper surface of the stand 54A so as to be slidable between the restricted position shown in Figure 6(A) and the permitted position shown in Figure 6(B). In the restricted position, the upper position stopper 55A is interposed between the spacer rod 53A, which has been removed upward from the through hole 57A, and the stand 54A. This prevents the spacer rod 53A from entering the through hole 57A. As a result, the injection device 30 and the C frame 12 are positioned in the upper position. On the other hand, in the permitted position, the upper position stopper 55A retracts from between the spacer rod 53A and the stand 54A, allowing the spacer rod 53A to enter the through hole 57A.

[0038] As shown in Figure 7, the lower stopper 56A is fixed to the lower surface of the injection device 30 and the C-frame 12 at a position adjacent to the spacer rod 53A in the horizontal direction and facing the stand 54A in the vertical direction. That is, the lower stopper 56A moves up and down together with the injection device 30 and the C-frame 12. As shown in Figure 7(A), when the injection device 30 and the C-frame 12 are in the upper position, the lower stopper 56A is located above the stand 54A. On the other hand, as shown in Figure 7(B), when the injection device 30 and the C-frame 12 are in the lower position, the lower stopper 56A contacts the upper surface of the stand 54A with the spacer rod 53A entering the through hole 57A. As a result, the injection device 30 and the C-frame 12 are positioned in the lower position.

[0039] Figure 8 is a hardware configuration diagram of the die-casting machine 10. The die-casting machine 10 includes a control device 60. The control device 60 includes, for example, a CPU (Central Processing Unit) 61 which is a calculation means, a ROM (Read Only Memory) 62 which stores various programs, and a RAM (Random Access Memory) 63 which serves as a workspace for the calculation means. The CPU 61 may read and execute the programs stored in the ROM 62 to realize the various processes described later.

[0040] However, the specific configuration of the control device 60 is not limited to this and may be implemented using hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array).

[0041] The control device 60 controls the operation of the entire die-casting machine 10. More specifically, the control device 60 controls the operation of the clamping device 20, injection device 30, hot water supply device 40, and lifting device 50 based on various signals output from the pressure sensor 35, attitude sensor 44, and display input device 64.

[0042] The display input device 64 is a user interface that includes a display for displaying various information to be communicated to the operator, and buttons, switches, dials, etc., for receiving input operations from the operator. The display input device 64 may also include a touch panel superimposed on the display. The display input device 64 receives input operations from the operator and outputs an input signal corresponding to the received input operation to the control device 60.

[0043] The display input device 64 receives input from an operator to set the pressure of the hydraulic fluid stored in the accumulator 34. The control device 60 then supplies and discharges hydraulic fluid to the accumulator 34 so that the pressure reaches the set pressure via the display input device 64.

[0044] Furthermore, the display input device 64 receives input from the operator to indicate the orientation of the hot water heater 40. The control device 60 then drives the motor 43 so that the hot water heater 40 is in the orientation supported by the display input device 64. The display input device 64 also indicates whether the current orientation of the hot water heater 40 is an intermediate orientation between Figure 5(B) and Figure 5(C). In other words, the operator can adjust the orientation of the hot water heater 40 while looking at the display on the display input device 64.

[0045] Furthermore, the display input device 64 receives input from the operator to instruct the raising and lowering of the injection device 30 and the C-frame 12. Then, the control device 60 executes the raising and lowering control process shown in Figure 9 in response to the instruction to raise and lower the injection device 30 and the C-frame 12 via the display input device 64. Figure 9 is a flowchart of the raising and lowering control process.

[0046] First, the control device 60 determines whether the pressure of the hydraulic fluid stored in the accumulator 34 is within the permissible range based on the pressure signal output from the pressure sensor 35 (S11). The control device 60 also determines whether the hot water supply device 40 is in an intermediate position between Figure 5(B) and Figure 5(C) based on the attitude signal output from the attitude sensor 44 (S12). Note that the execution order of steps S11 and S12 is not limited to the example in Figure 9, and may be in reverse order.

[0047] Here, when the pressure of the hydraulic fluid stored in the accumulator 34 is within the permissible range and the hot water supply device 40 is in an intermediate position, the conditions are such that, when the die-casting machine 10 is viewed from above, the center of gravity of the entire injection device 30, C-frame 12, and hot water supply device 40 approaches the point of application P to the extent that the injection device 30 and C-frame 12 can be raised and lowered while maintaining their horizontal position.

[0048] Therefore, when the control device 60 determines that the pressure of the hydraulic fluid stored in the accumulator 34 is within an acceptable range and the hot water supply device 40 is in an intermediate position (S11: Yes & S12: Yes), it extends and retracts the lifting cylinder 51 so that the injection device 30 and the C-frame 12 move up and down in the direction indicated via the display input device 64 (S13). In other words, the control device 60 allows the extension and retraction of the lifting cylinder 51 when the pressure of the hydraulic fluid stored in the accumulator 34 is within an acceptable range and the hot water supply device 40 is in an intermediate position.

[0049] On the other hand, if either or both of the conditions in steps S11 and S12 are not met (S11: No / S12: No), the control device 60 notifies the operator via the display input device 64 that it is not possible to raise or lower the injection device 30 and the C-frame 12 instead of performing the process in step S13 (i.e., without extending or retracting the lifting cylinder 51) (S14). In other words, the control device 60 restricts the extension and retraction of the lifting cylinder 51 if the pressure of the hydraulic fluid stored in the accumulator 34 is outside the permissible range, or if the hot water supply device 40 is in the pouring position or the hot water supply position.

[0050] According to the above embodiment, for example, the following effects are achieved.

[0051] According to the above embodiment, the extension and retraction of the lifting cylinder 51 is permitted when the pressure of the hydraulic fluid stored in the accumulator 34 is within the permissible range and the hot water supply device 40 is in an intermediate position (S11: Yes & S12: Yes). As a result, the lifting cylinder 51 is extended and retracted when the center of gravity of the entire injection device 30, C-frame 12, and hot water supply device 40 approaches the point of action P. Consequently, the injection device 30 and C-frame 12 can be raised and lowered while maintaining a horizontal position with a simple configuration.

[0052] Furthermore, according to the above embodiment, the lifting cylinder 51 is extended and retracted while the hot water supply device 40 is in an intermediate position, extending to one side in the width direction from the pouring position. This prevents the hot water supply device 40 from interfering with the lifting operation of the injection device 30 and the C-frame 12. In order to balance the hot water supply device 40 in the intermediate position, it is desirable that the point of application P at which the lifting cylinder 51 applies thrust to the injection device 30 and the C-frame 12 be located near an intermediate position between the center of gravity positions G3 and G4 of the hot water supply device 40 in the intermediate position and the center of gravity position G5 of the injection device 30 and the C-frame 12.

[0053] Furthermore, according to the above embodiment, by providing positioning mechanisms 52A and 52B on both sides of the lifting cylinder 51 in the longitudinal direction, the injection device 30 and the C frame 12 can be positioned in the upper and lower positions while maintaining a horizontal state.

[0054] Furthermore, according to the above embodiment, the upper position stopper 55A can be switched between positioning in the upper position and releasing the position simply by sliding it on the stand 54A. This simplifies the operation of raising and lowering the injection device 30 and the C-frame 12 compared to, for example, attaching and detaching the spacer rod 53A. However, the specific configuration of the positioning mechanisms 52A and 52B is not limited to the example described above.

[0055] In the above embodiment, an example was described in which the extension and retraction of the lifting cylinder 51 is determined based on two conditions: the pressure of the hydraulic fluid stored in the accumulator 34 and the posture of the hot water supply device 40. However, it is also possible to determine whether or not the extension and retraction of the lifting cylinder 51 is permitted based on only the condition that has a significant effect on the change in the center of gravity position. In other words, one of steps S11 and S12 in Figure 9 may be omitted.

[0056] Furthermore, although the above embodiment describes an example in which an operator operates the display input device 64 to satisfy the conditions of steps S11 and S12, the work to satisfy the conditions of steps S11 and S12 is not limited to being performed by an operator.

[0057] As another example, if the control device 60 determines that the conditions of step S11 are not met, it may supply or discharge hydraulic fluid to the accumulator 34 so that the pressure of the hydraulic fluid stored in the accumulator 34 falls within an acceptable range. Also, if the control device 60 determines that the conditions of step S12 are not met, it may drive the motor 43 so that the hot water supply device 40 is in an intermediate position. This further simplifies the operation of raising and lowering the injection device 30 and the C-frame 12.

[0058] The embodiments described above are illustrative for explaining the present invention and are not intended to limit the scope of the invention to those embodiments only. Those skilled in the art can implement the present invention in various other forms without departing from the spirit of the invention. [Explanation of symbols]

[0059] 10…Die casting machine, 11…Base, 12…C-frame, 20…Clamping device, 21…Mold, 22…Fixed mold, 23…Fixed die plate, 24…Movable mold, 25…Movable die plate, 26…Mold opening / closing cylinder, 27…Toggle link mechanism, 28…Tie bar, 30…Injection device, 31…Injection sleeve, 32…Plunger, 33…Injection cylinder, 34…Accumulator, 35…Pressure sensor, 40…Hot water supply device, 41…Rudder, 42…Link mechanism, 43…Motor, 44…Attitude sensor, 50…Lifting device, 51…Lifting cylinder, 52A, 52B…Positioning mechanism, 53A…Spacer rod, 54A…Stand, 55A…Upper position stopper, 56A…Lower position stopper, 57A…Through hole, 60…Control device, 61…CPU, 62…ROM, 64…Display input device

Claims

1. A clamping device for opening, closing, and clamping the fixed mold and the movable mold, An injection device for injecting molten metal into cavities formed inside the fixed mold and the movable mold, which are clamped by the clamping device, A die-casting machine comprising a C-frame, the open end of which is C-shaped, is connected to the clamping device so as to be able to move up and down, and the closed end is fixed to the injection device, A lifting cylinder that extends and retracts vertically below the injection device, thereby raising and lowering the injection device and the C-frame relative to the clamping device, A molten metal supply device that changes its position to a supply position for supplying molten metal from a melting furnace, a pouring position for pouring molten metal into the injection device, and an intermediate position between the supply position and the pouring position. The system includes a control device for controlling the extension and retraction of the lifting cylinder, The injection device is, A sleeve communicating with the aforementioned cavity, A plunger that advances within the sleeve toward the cavity, thereby supplying molten metal within the sleeve to the cavity, An injection cylinder that advances the plunger when hydraulic fluid is supplied to the head chamber, and retracts the plunger when hydraulic fluid is supplied to the rod chamber, It comprises an accumulator positioned on the opposite side of the C-frame from the lifting cylinder in the longitudinal direction, which supplies pre-pressurized hydraulic fluid to the head chamber, The center of gravity of the injection device and the C-frame moves further away from the lifting cylinder in the longitudinal direction as the amount of hydraulic fluid in the accumulator increases. The hot water supply device is supported by the C-frame on the side opposite to the accumulator, with the lifting cylinder in between, in the longitudinal direction and the width direction perpendicular to the longitudinal direction. When the die-casting machine is viewed from above, The center of gravity of the hot water supply device in the hot water supply position is closer to the lifting cylinder in the longitudinal direction and protrudes to one side in the width direction than the center of gravity of the hot water supply device in the pouring position. The center of gravity of the hot water supply device in the intermediate position is located between the center of gravity of the hot water supply device in the hot water supply position and the center of gravity of the hot water supply device in the hot water pouring position, in the longitudinal and width directions. The control device is When the amount of hydraulic fluid in the accumulator is within an acceptable range and the hot water supply device is in the intermediate position, the extension and retraction of the lifting cylinder is permitted. A die-casting machine characterized in that the extension and retraction of the lifting cylinder is restricted when the amount of hydraulic fluid in the accumulator is outside the allowable range, or when the hot water supply device is in the hot water pouring position or the hot water supply position.

2. The die-casting machine according to claim 1, further comprising a pair of positioning mechanisms positioned below the injection device and the C-frame and on both sides of the lifting cylinder in the longitudinal direction, for positioning the injection device and the C-frame in an upper position and a lower position below the upper position, respectively.

3. The positioning mechanism is A spacer rod that moves up and down together with the injection device and the C-frame, A stand fixed below the injection device and the C-frame, having a through hole into which the spacer rod can enter, An upper position stopper is interposed between the spacer rod and the stand, which have been removed upward from the through hole, to prevent the spacer rod from entering the through hole, thereby positioning the injection device and the C-frame in the upper position. The die-casting machine according to claim 2, further comprising a lower position stopper that moves up and down together with the spacer rod, and which positions the injection device and the C-frame in the lower position by contacting the upper surface of the stand when the spacer rod has entered the through hole.

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