JP2018176192A - Die casting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die-casting machine capable of effectively suppressing a phenomenon that high pressure is applied to a molten metal filled into a mold in an un-warmed state.SOLUTION: There is provided an electric die-casting machine 1 controlling a first electric motor 11 and a second electric motor 12 in such a manner that a control part 30 practices a low speed injection operation of progressing an injection plunger 20 at a low objective velocity V1 and a first warm up operation including a warm up pressure increase operation of pressing the injection plunger 20 to the front direction at a warm up pressure increase objective pressure Pw lower than an ordinary pressure increase objective pressure Pm.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a die casting machine.

  Patent Document 1 discloses a conventional die casting machine. This die casting machine has a cylindrical injection sleeve to which molten metal is supplied, and an injection plunger moved back and forth in the injection sleeve, and the molten metal is injected into the cavity of a mold closed by advancing the injection plunger. A hydraulic operation means and an electric servomotor are used as a drive source of the injection process to be filled. This die casting machine has an injection mechanism for injecting molten metal into the cavity of the mold and an pressurizing mechanism for pushing the molten metal charged into the cavity of the mold by means of hydraulic operation means and an electric servomotor. And a pressure-increasing mechanism.

  Generally, a die-casting machine has a configuration in which two linear drive systems of an injection mechanism and a pressure-increasing mechanism are connected in multiple stages, but a small die-casting machine is composed of one hydraulic operating means or one electric motor. It has only an injection mechanism as a linear drive system, and does not have a pressure increasing mechanism. In such a small die casting machine, the injection mechanism performs both the injection operation and the pressure increase operation.

JP, 2013-184211, A

  In die casting machines, a warm-up operation is performed to warm the mold prior to the product manufacturing operation. However, in a die casting machine having only an injection mechanism, since the injection mechanism performs a series of operations from the injection operation to the pressure increase operation, the molten metal filled in the mold that is not sufficiently warmed during the warm-up operation is relatively high. There is a possibility that intensified pressure may be applied.

  Then, an object of this invention is to provide the die-cast machine which can suppress effectively that a high pressure is added to the molten metal with which the metal mold | die in the unheated state was filled.

  In order to achieve the above object, a die casting machine according to the present invention is a die casting machine having an injection plunger, a drive unit for moving the injection plunger forward, and a control unit for controlling the drive unit, The drive unit has only one linear drive system, and the control unit performs: (1) a low speed injection operation for advancing the injection plunger at a low target speed, a high speed injection operation for advancing the injection plunger at a high target speed; And (2) the low-speed injection operation, and a product manufacturing mode in which the drive unit is controlled to perform an injection filling operation including a normal pressure increase operation of pressing the injection plunger forward with a normal pressure increase target pressure. At least including a warm-up pressure-increasing operation for pressing the injection plunger forward with a warm-up pressure-increasing target pressure lower than the normal pressure-increasing target pressure And having a warm-up mode for controlling the driving unit to perform Muappu operation, the.

  According to the present invention, the control unit performs the low speed injection operation for advancing the injection plunger at the low speed target speed, and the warm up pressure increase for pressing the injection plunger forward with the warm up pressure increase target pressure lower than the normal pressure increase target pressure. The drive unit is controlled to perform a warm-up operation including at least an operation. Since it did in this way, it shifts to a warm up mode and performs warm up operation before product manufacture mode, and performs pressure increase operation with a warm up pressure increase target pressure lower than a normal pressure increase target pressure. be able to.

  In the present invention, the warm-up operation preferably includes the high-speed injection operation. In this way, in the warm-up operation, the low-speed injection operation, the high-speed injection operation, and the warm-up pressure increase operation are performed, so that an operation closer to a general start-up operation of product manufacture can be performed.

  In the present invention, preferably, the control unit is automatically started in the warm-up mode and executes the warm-up operation, and then automatically shifts to the product manufacturing mode. By doing this, it is possible to prevent an injection filling operation for manufacturing a normal product from being accidentally performed immediately after startup.

  In the present invention, the drive unit includes one electric motor controlled by the control unit or a plurality of electric motors controlled identically to the control unit, and the control unit performs the warm-up pressure increase operation. Controlling the electric motor such that the injection plunger is pressed forward by the warm-up pressure increase target pressure and the injection plunger is pressed forward by the normal pressure increase target pressure in the normal pressure increase operation. preferable. In this way, in the electric die casting machine, for example, the warm-up pressure-increasing operation can be performed relatively easily by controlling the value of the current flowing through the electric motor.

  In the present invention, the drive unit includes: an injection piston connected to the injection plunger; an injection cylinder accommodating the injection piston; hydraulic operation means for applying oil pressure to the injection cylinder; and reducing oil pressure of the injection cylinder The control unit applies a hydraulic pressure to become the normal pressure increase target pressure to the injection cylinder in the normal pressure increase operation, and the control unit applies the hydraulic pressure to the injection cylinder in the warm-up pressure increase operation. It is preferable to control the hydraulic operating means and the pressure reducing means so as to apply a hydraulic pressure which is a normal pressure increase target pressure and reduce the oil pressure of the injection cylinder to the warm-up pressure increase target pressure. In this way, in the hydraulic die casting machine, the warm-up pressure-increasing operation can be performed with a relatively simple configuration.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress effectively that big pressure is added to the molten metal with which the metal mold | die of the state which is not warmed is filled. Therefore, the life of the mold can be extended.

It is a figure showing a schematic structure of an electric die-cast machine concerning a 1st embodiment of the present invention. It is a graph explaining an example of operation | movement of the electrically-driven die-cast machine of FIG. It is a figure showing a schematic structure of a hydraulic die-cast machine concerning a 2nd embodiment of the present invention.

First Embodiment
Hereinafter, the electric die-casting machine according to the first embodiment of the present invention will be described with reference to FIG. 1 and FIG.

  FIG. 1 is a view showing a schematic configuration of an electric die casting machine according to an embodiment of the present invention. As shown in FIG. 1, the electric die casting machine 1 of this embodiment includes a first electric motor 11, a second electric motor 12, a ball screw mechanism 13, a first power transmission mechanism 14, and a second power transmission mechanism. A shock absorbing mechanism 18, a linear motion body 19, an injection plunger 20, a load cell 21, a position sensor 22, and a control unit 30.

  The first electric motor 11 and the second electric motor 12 are, for example, constituted by electric servomotors having the same configuration as each other, and are controlled by a control signal transmitted from the control unit 30 described later. One of the first electric motor 11 and the second electric motor 12 is a master motor, and the other is a slave motor, and the slave motors follow the master motor and rotate at the same speed in the same direction. That is, the first electric motor 11 and the second electric motor 12 perform the same operation by being controlled identically by one control system. In the present embodiment, two electric motors are provided. However, the present invention is not limited to this, and one electric motor or a plurality of three or more of the same controlled by one control system are used. It is good also as composition provided with an electric motor.

  The ball screw mechanism 13 has a screw shaft 13a and a nut body 13b screwed to the screw shaft 13a via a ball (not shown). In the ball screw mechanism 13, the nut body 13b linearly moves in the axial direction of the screw shaft 13a as the screw shaft 13a is rotated about the axis.

  The first power transmission mechanism 14 is an endless belt-like timing belt 14b bridged between a first pulley 14a coaxially provided with the screw shaft 13a and the first pulley 14a and an output pulley 11a of the first electric motor 11. And. The first power transmission mechanism 14 transmits the rotational output of the first electric motor 11 to the screw shaft 13a to rotate the screw shaft 13a around the shaft.

  Similarly to the first power transmission mechanism, the second power transmission mechanism 15 also spans the second pulley 15a provided coaxially with the screw shaft 13a, the second pulley 15a, and the output pulley 12a of the second electric motor 12. And an endless belt-like timing belt 15b. The second power transmission mechanism 15 transmits the rotational output of the second electric motor 12 to the screw shaft 13a to rotate the screw shaft 13a around the shaft.

  The rotational outputs of the first electric motor 11 and the second electric motor 12 are directly transmitted to the screw shaft 13 a by the first power transmission mechanism 14 and the second power transmission mechanism 15.

  The first electric motor 11, the second electric motor 12, the ball screw mechanism 13, the first power transmission mechanism 14 and the second power transmission mechanism 15 are drives having one linear drive system for moving the injection plunger 20 in the forward direction. Make up the department. One linear drive system is a mechanism that moves linearly by one drive system (one electric motor, or multiple electric motors controlled by one control system, or a pair of injection piston and injection cylinder) Say

  The shock absorbing mechanism 18 includes a first member 18 a, a second member 18 b, and an elastic member 18 c. The first member 18a is formed in an annular shape, and is fixed to and attached to the nut body 13b in a state where the nut body 13b is inserted inside. The second member 18b is annularly formed, has the nut body 13b inserted therein, and is connected to the first member 18a by a connecting member such as a bolt (not shown) with the elastic member 18c interposed therebetween. The second member 18b is not fixed to the nut body 13b.

  The first elastic member 18c is applied with a compressive force equal to or slightly (for example, 1.05 to 1.1 times) greater than the molten metal pressure at the time of switching from the high speed injection step to the pressure increase step. It is disposed between the member 18a and the second member 18b. As a result, the elastic member 18c does not shrink during the high-speed injection process, and the required injection pressure can be applied to the molten metal, and the elastic member 18c shrinks when a large pressure is instantaneously applied, resulting in a large pressure. Damage to the device due to

  The linear moving body 19 is provided at a cylindrical main portion 19a into which the screw shaft 13a is inserted, a wall 19b closing an end of the distal end of the main portion 19a, and a rear end of the main portion 19a. And a flange portion 19c. The flange portion 19 c is fixedly attached to the second member 18 b of the shock absorbing mechanism 18.

  The injection plunger 20 is formed in a cylindrical shape, and one end thereof is fixedly attached to the tip of the linear moving body 19. The injection plunger 20 is attached to the nut body 13b via the linear motion body 19 and the shock absorbing mechanism 18, and is linearly moved along with the nut body 13b.

  The load cell 21 detects the pressure applied to the screw shaft 13a, and transmits a signal indicating the pressure to the control unit 30.

  The position sensor 22 is, for example, a linear encoder, detects the position of the linear moving body 19 in the front-rear direction, and transmits a signal indicating the position of the linear moving body 19 to the control unit 30.

  The control unit 30 includes, for example, a microcomputer for an embedded device having a CPU, a ROM, a RAM, an EEPROM, various I / O interfaces, and the like. The control unit 30 controls the entire electric die casting machine 1 and performs each process such as a clamping process, a low speed injection process, a high speed injection process, a normal pressure increasing process, a warm up pressure increasing process, a mold opening process and a product taking out process. It controls the operations of the first electric motor 11 and the second electric motor 12, and driving devices such as a mold opening / closing actuator and a product taking out actuator (not shown).

  The control unit 30 is connected to the first electric motor 11 and the second electric motor 12, and transmits control signals regarding start / stop and rotational speed to these electric motors.

  The control unit 30 is connected to the load cell 21 and detects a pressure P for pressing the injection plunger 20 based on a signal from the load cell 21. The load cell 21 and the control unit 30 constitute a pressure detection unit. In the present embodiment, the pressure P for pressing the injection plunger 20 and the injection pressure of the injection plunger 20 are configured to be the same. The control unit 30 is connected to the position sensor 22 and detects the forward and backward movement position L and the velocity V of the injection plunger 20 based on the signal from the position sensor 22. The position sensor 22 and the control unit 30 constitute a position detection unit and a speed detection unit.

  The control unit 30 performs feedback control (PID control) of the first electric motor 11 and the second electric motor 12 using the detected pressure P for pressing the injection plunger 20 and the forward / backward advancing position L and speed V. Further, the control unit 30 detects the torque of the first electric motor 11 and the second electric motor 12 based on the control signal transmitted to the first electric motor 11 and the second electric motor 12. The control unit 30 controls the current (that is, the torque) flowing to the first electric motor 11 and the second electric motor 12 according to the control signal.

  The control unit 30 has, as an operation mode, a product manufacturing mode for executing an injection filling operation for manufacturing a product, and a warm-up mode for executing a warm-up operation for warming a mold. In the present embodiment, the control unit 30 starts in the warm-up mode, and automatically shifts to the product manufacturing mode when a predetermined condition is satisfied. Here, the predetermined condition is, for example, that the warm-up operation is performed more than a predetermined number of warm-up times, the temperature of the mold is monitored, and the temperature of the mold exceeds the mode shift reference value. is there. It is also possible to shift from the warm-up mode to the product manufacturing mode manually.

  Next, an example of the operation of the electric die casting machine 1 of the present embodiment described above will be described with reference to FIG. FIG. 2 is a graph showing an example of the operation of the electric die casting machine of FIG. 1, wherein (a) is a first warm-up operation, (b) is a second warm-up operation, and (c) is product manufacture Injection filling operation. In these graphs, the horizontal axis is time, and the vertical axis is the velocity of the injection plunger and the pressure for pressing the injection plunger.

  The electric die casting machine 1 (specifically, the control unit 30) starts up in the warm-up mode. Then, the electric die-casting machine 1 first executes a first warm-up operation shown in FIG. 2 (a).

  As shown in FIG. 2A, in the first warm-up operation, the control unit 30 starts the rotation operation of the first electric motor 11 and the second electric motor 12 as the low speed injection operation, and the speed of the injection plunger 20 Is advanced at a constant low target velocity V1 (e.g. 0.2 m / sec). Then, when the advancing position of the injection plunger 20 reaches the predetermined pressure increase switching position L2, the control unit 30 performs a warm-up pressure increase operation such that the pressure P for pressing the injection plunger 20 is the warm-up pressure increase target pressure Pw (for example, The first electric motor 11 and the second electric motor 12 are controlled to be 30 MPa. Thereby, the control unit 30 increases the torques of the first electric motor 11 and the second electric motor 12, and the pressure P for pressing the injection plunger 20 accordingly increases to the warm-up pressure increase target pressure Pw. The warm-up pressure increase target pressure Pw is held for a certain period. Thereafter, the control unit 30 retracts the injection plunger 20 to release the pressing, and the mold is opened to take out the molded product. When the first warm-up operation is performed a predetermined number of times (for example, 10 times), the electric die-casting machine 1 next executes a second warm-up operation shown in FIG. 2 (b).

  As shown in FIG. 2B, in the second warm-up operation, the control unit 30 starts the rotation operation of the first electric motor 11 and the second electric motor 12 as the low speed injection operation, and the speed of the injection plunger 20 Is advanced at a constant low target velocity V1. Then, when the advancing position of the injection plunger 20 reaches the predetermined high speed switching position L1, the control unit 30 increases the rotational speeds of the first electric motor 11 and the second electric motor 12 as high speed injection operations to set the injection plunger 20 The speed is rapidly increased and then advanced at a constant high speed target speed V2 (for example, 2.0 m / sec). Then, when the advancing position of the injection plunger 20 reaches the predetermined pressure increase switching position L2, the control unit 30 performs the warm-up pressure increase operation so that the pressure P for pressing the injection plunger becomes the warm-up pressure increase target pressure Pw. The first electric motor 11 and the second electric motor 12 are controlled. Thereby, the control unit 30 increases the torques of the first electric motor 11 and the second electric motor 12, and the pressure P for pressing the injection plunger 20 accordingly increases to the warm-up pressure increase target pressure Pw. The warm-up pressure increase target pressure Pw is held for a certain period. Thereafter, the control unit 30 retracts the injection plunger 20 to release the pressing, and the mold is opened to take out the molded product. When the second warm-up operation is performed a predetermined number of times (for example, 10 times), next, the control unit 30 of the electric die-casting machine 1 automatically shifts from the warm-up mode to the product manufacturing mode. Execute the injection filling operation shown in 2.).

  As shown in FIG. 2C, in the injection filling operation, the control unit 30 starts the rotation operation of the first electric motor 11 and the second electric motor 12 as the low speed injection operation, and the speed of the injection plunger 20 is constant. Advance at a low target speed V1 of Then, when the advancing position of the injection plunger 20 reaches the predetermined high speed switching position L1, the control unit 30 increases the rotational speeds of the first electric motor 11 and the second electric motor 12 as high speed injection operations to set the injection plunger 20 The speed is rapidly increased and then advanced at a constant high speed target speed V2. Then, when the advancing position of the injection plunger 20 reaches the predetermined pressure increase switching position L2, the control unit 30 performs the normal pressure increase operation, the pressure P for pressing the injection plunger 20 is usually the target pressure increase pressure Pm (for example, 60 MPa) The first electric motor 11 and the second electric motor 12 are controlled so that Thereby, the control unit 30 increases the torques of the first electric motor 11 and the second electric motor 12, and the pressure P for pressing the injection plunger 20 accordingly increases to the normal pressure increase target pressure Pm. The intensified target pressure Pm is held for a fixed period. Thereafter, the control unit 30 retracts the injection plunger 20 to release the push, and the mold is opened to take out a molded article to be a product. After that, the electric die-casting machine 1 repeatedly executes the injection filling operation.

  As described above, according to the electric die casting machine 1 of the present embodiment, the control unit 30 causes the injection plunger 20 to advance at the low target velocity V1 and performs the low speed injection operation. The first electric motor 11 and the second electric motor 12 are controlled to execute a first warm-up operation including a warm-up pressure-increasing operation of pressing forward with a lower warm-up pressure-increasing target pressure Pw. Because of this, by shifting to the warm-up mode and performing the warm-up operation before the product manufacturing mode, the pressure increase operation is performed with the warm-up pressure increase target pressure Pw lower than the normal pressure increase target pressure Pm. It can be performed.

  In addition, by including the high-speed injection operation in the second warm-up operation following the first warm-up operation, first, the low-speed injection operation and the warm-up pressure increase operation are performed in the first warm-up operation, and then the second warm-up operation is performed. Since the low speed injection operation, the high speed injection operation and the warm-up pressure increase operation are performed in operation, it is possible to gradually approach the general start-up operation of product manufacture.

  In addition, since the control unit 30 starts up in the warm-up mode and executes the first warm-up operation and the second warm-up operation, the control unit 30 automatically shifts to the product manufacturing mode. It is possible to prevent the injection filling operation for manufacturing from being performed.

Second Embodiment
Hereinafter, a hydraulic die-casting machine according to a second embodiment of the present invention will be described with reference to FIG.

  FIG. 3 is a view showing a schematic configuration of a hydraulic die casting machine according to an embodiment of the present invention. As shown in FIG. 3, the hydraulic die casting machine 51 of this embodiment includes an injection plunger 61, an injection piston 62, a connecting member 63, an injection cylinder 64, hydraulic operation means 71, pressure reducing means 75, and a tank 79. And the control unit 80.

  The injection plunger 61 is disposed so as to be movable forward and backward (movable in the front-rear direction) in an injection sleeve formed on a fixed die plate (not shown). The injection piston 62 is connected to the rear end portion of the injection plunger 61 via a connection member 63. The injection cylinder 64 accommodates the injection piston 62 so as to be movable back and forth.

  The hydraulic operating means 71 has an accumulator 72 and a flow rate adjustment valve 73. The accumulator 72 is connected to the first oil chamber 64a, which is a space on the rear side of the injection piston 62 of the injection cylinder 64 through the flow control valve 73, opens the flow control valve 73, and operates from the accumulator 72 to the first oil chamber 64a. As the oil flows in, the pressure (hydraulic pressure) of the first oil chamber 64a increases, and the injection piston 62 advances. At this time, the forward speed of the injection piston 62 is adjusted by the opening degree of the flow rate adjustment valve 73. A second oil chamber 64 b which is a space on the front side of the injection cylinder 64 is connected to the tank 79. Although not shown, the hydraulic die casting machine 51 is also provided with a mechanism for moving the injection piston 62 backward.

  The pressure reducing means 75 has a control valve 76 and a relief valve 77 connected in series with each other. The control valve 76 is connected to the first oil chamber 64 a of the injection cylinder 64, and the relief valve 77 is connected to the tank 79. The control valve 76 is, for example, a two-port single-acting normally closed solenoid valve, and connects the first oil chamber 64a and the relief valve 77 in the on state and disconnects them in the off state. When the control valve 76 is turned on and the first oil chamber 64a and the relief valve 77 are connected, the hydraulic oil in the first oil chamber 64a flows to the tank 79 through the relief valve 77, and the oil pressure of the first oil chamber 64a is The pressure is reduced to the set pressure of the relief valve 77. In the present embodiment, the set pressure of the relief valve 77 is set to the warm-up pressure increase target pressure Pw.

  The injection piston 62, the connection member 63, the injection cylinder 64, the hydraulic operation means 71, and the pressure reducing means 75 constitute a drive unit having one linear drive system for moving the injection plunger 61 in the forward direction.

  Further, the hydraulic die casting machine 51 has a pressure sensor and a position sensor (not shown). The pressure sensor detects a pressure P pressing the injection plunger 61, and transmits a signal indicating the pressure to the control unit 80. The position sensor is, for example, a linear encoder, detects the position of the injection plunger 61 in the front-rear direction, and transmits a signal indicating the detected position to the control unit 80.

  The control unit 80 includes, for example, a microcomputer for an embedded device having a CPU, a ROM, a RAM, an EEPROM, various I / O interfaces, and the like. The control unit 80 controls the entire hydraulic die casting machine 51, and performs each process such as a clamping process, a low speed injection process, a high speed injection process, a normal pressure increasing process, a warm up pressure increasing process, a mold opening process and a product taking out process. It controls the operation of the accumulator 72, the flow control valve 73 and the control valve 76, and driving devices such as a mold opening / closing actuator and a product taking out actuator (not shown).

  The control unit 80 is connected to the accumulator 72, the flow control valve 73 and the control valve 76, transmits a control signal related to the pressure of the hydraulic fluid to the accumulator 72, and the flow rate of the hydraulic fluid to the flow control valve 73. Control signal related to connection (on state) and disconnection (off state) to the control valve 76.

  The control unit 80 is connected to a pressure sensor (not shown), and detects a pressure P for pressing the injection plunger 61 based on a signal from the pressure sensor. The pressure sensor and the control unit 80 constitute a pressure detection unit. The control unit 80 is connected to a position sensor (not shown), and detects the forward and backward movement position L and the speed V of the injection plunger 61 based on a signal from the position sensor. The position sensor and the control unit 80 constitute a position detection unit and a speed detection unit.

  The control unit 80 has, as operation modes, a product manufacturing mode for executing an injection filling operation for manufacturing a product, and a warm-up mode for executing a warm-up operation for warming a mold. In the present embodiment, the control unit 80 starts in the warm-up mode, and automatically shifts to the product manufacturing mode when a predetermined condition is satisfied. Here, the predetermined condition is, for example, that the warm-up operation is performed more than a predetermined number of warm-up times, the temperature of the mold is monitored, and the temperature of the mold exceeds the mode shift reference value. is there. It is also possible to shift from the warm-up mode to the product manufacturing mode manually.

  Next, an example of the operation of the hydraulic die casting machine 51 of the present embodiment described above will be described with reference to FIG. FIG. 2 is a graph showing an example of the operation of the electric die-casting machine of FIG. 1, but the same operation is performed in the hydraulic die-casting machine of FIG.

  The hydraulic die casting machine 51 (specifically, the control unit 80) starts in the warm-up mode. Then, the hydraulic die-casting machine 51 first executes a first warm-up operation shown in FIG. 2 (a).

  As shown in FIG. 2A, in the first warm-up operation, the control unit 80 first raises the pressure of the hydraulic oil of the accumulator 72 to the normal pressure increase target pressure Pm (for example, 15 MPa). At this time, the control valve 76 is off. Next, as the low speed injection operation, the control unit 80 opens the flow rate adjustment valve 73 to advance the speed of the injection plunger 61 at a constant low speed target speed V1 (for example, 0.2 m / sec). Then, when the forward movement position of the injection plunger 61 reaches the predetermined pressure increase switching position L2, the control unit 80 turns on the control valve 76 as a warm-up pressure increase operation and releases the first oil chamber 64a of the injection cylinder 64 and the relief. Connect with the valve 77. As a result, the hydraulic pressure of the first oil chamber 64a becomes the warm-up pressure increase target pressure Pw (for example, 7.5 MPa) which is the set pressure of the relief valve 77, and this pressure is maintained for a certain period. Thereafter, the control unit 80 retracts the injection plunger 61 to release the push, and the mold is opened to take out the molded product. When the first warm-up operation is performed a predetermined number of times (for example, ten times), next, the hydraulic die-casting machine 51 executes a second warm-up operation shown in FIG. 2 (b).

  As shown in FIG. 2B, in the second warm-up operation, the control unit 80 first raises the pressure of the hydraulic oil of the accumulator 72 to the normal pressure increase target pressure Pm. At this time, the control valve 76 is off. Next, as the low speed injection operation, the control unit 80 opens the flow rate adjustment valve 73 to advance the speed of the injection plunger 61 at a constant low speed target speed V1. When the advancing position of the injection plunger 61 reaches the predetermined high-speed switching position L1, the control unit 80 further opens the flow rate adjusting valve 73 to rapidly increase the speed of the injection plunger 61 as a high-speed injection operation. Forward at a high speed target velocity V2 (e.g., 2.0 m / sec). Then, when the forward movement position of the injection plunger 61 reaches the predetermined pressure increase switching position L2, the control unit 80 turns on the control valve 76 as a warm-up pressure increase operation and releases the first oil chamber 64a of the injection cylinder 64 and the relief. Connect with the valve 77. As a result, the oil pressure of the first oil chamber 64a becomes the warm-up pressure increase target pressure Pw, and this pressure is maintained for a certain period. Thereafter, the control unit 80 retracts the injection plunger 61 to release the push, and the mold is opened to take out the molded product. When the second warm-up operation is performed a predetermined number of times (for example, 10 times), next, the control unit 80 of the hydraulic die-casting machine 51 automatically shifts from the warm-up mode to the product manufacturing mode. Execute the injection filling operation shown in 2.).

  As shown in FIG. 2C, in the injection filling operation, the control unit 80 first raises the pressure of the hydraulic oil of the accumulator 72 to the normal pressure increase target pressure Pm. At this time, the control valve 76 is off. Next, as the low speed injection operation, the control unit 80 opens the flow rate adjustment valve 73 to advance the speed of the injection plunger 61 at a constant low speed target speed V1. When the advancing position of the injection plunger 61 reaches the predetermined high-speed switching position L1, the control unit 80 further opens the flow rate adjusting valve 73 to rapidly increase the speed of the injection plunger 61 as a high-speed injection operation. Advance at the high speed target speed V2. Then, when the advancing position of the injection plunger 61 reaches the predetermined pressure increase switching position L2, the control unit 80 continues maintaining the off state of the control valve 76 as a normal pressure increase operation, and the first oil chamber of the injection cylinder 64. 64a and the relief valve 77 are kept disconnected. As a result, the hydraulic pressure of the first oil chamber 64a becomes the normal pressure increase target pressure Pm, and this pressure is maintained for a certain period. Thereafter, the control unit 80 retracts the injection plunger 61 to release the push, and the mold is opened to take out a molded article as a product. After that, the hydraulic die casting machine 51 repeatedly executes the injection filling operation.

  As described above, according to the hydraulic die-casting machine 51 of the present embodiment, the control unit 80 causes the injection plunger 61 to advance at the low target velocity V1 and performs the low speed injection operation. The accumulator 72, the flow control valve 73 and the control valve 76 are controlled to execute a first warm-up operation including a warm-up pressure-increasing operation of pressing forward with a lower warm-up pressure-increasing target pressure Pw. Because of this, by shifting to the warm-up mode and performing the warm-up operation before the product manufacturing mode, the pressure increase operation is performed with the warm-up pressure increase target pressure Pw lower than the normal pressure increase target pressure Pm. It can be performed.

  In addition, by including the high-speed injection operation in the second warm-up operation following the first warm-up operation, first, the low-speed injection operation and the warm-up pressure increase operation are performed in the first warm-up operation, and then the second warm-up operation is performed. Since the low speed injection operation, the high speed injection operation and the warm-up pressure increase operation are performed in operation, it is possible to gradually approach the general start-up operation of product manufacture.

  In addition, since the control unit 80 starts in the warm-up mode and executes the first warm-up operation and the second warm-up operation, the control unit 80 automatically shifts to the product manufacturing mode. It is possible to prevent the injection filling operation for manufacturing from being performed.

  According to each embodiment described above, it is possible to effectively suppress that a large pressure is applied to the molten metal filled in the mold in the unheated state. Therefore, the life of the mold can be extended.

  Moreover, in each embodiment mentioned above, although it was the structure which performs a 1st warm-up operation and a 2nd warm-up operation in a warm-up mode, it is not limited to this, The 1st warm-up operation and the 1st Only one of the two warm-up operations may be executed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these examples. Those skilled in the art may appropriately add, delete, or change the design elements from the above-described embodiment, or may appropriately combine the features of the embodiment, as long as the gist of the present invention is included. Included in the scope of the invention.

First Embodiment
DESCRIPTION OF SYMBOLS 1 ... Electric die-cast machine, 11 ... 1st electric motor, 11a ... Output pulley, 12 ... 2nd electric motor, 12a ... Output pulley, 13 ... Ball screw mechanism, 13a ... Screw shaft, 13b ... Nut body, 14 ... 1st Power transmission mechanism, 14a: first pulley, 14b: timing belt, 15: second power transmission mechanism, 15a: second pulley, 15b: timing belt, 18: shock absorbing mechanism, 18a: first member, 18b: second 18c: elastic member 19: linear body 19a: main body 19b: wall 19c: flange 20: injection plunger 21: load cell 22: position sensor 30: controller 30: L: back and forth Position, L1: High speed switching position, L2: Pressure increasing switching position, P: Pressure, V: Speed, V1: Low speed target speed, V2: High speed target speed, Pw: Warm-up pressure increasing target pressure, m ... Normal pressure increasing the target pressure (Second Embodiment)
51 ... hydraulic die casting machine, 61 ... injection plunger, 62 ... injection piston, 63 ... connecting member, 64 ... injection cylinder, 64 a ... first oil chamber, 64 b ... second oil chamber, 71 ... hydraulic operation means, 72 ... accumulator, 73: flow rate adjusting valve, 75: pressure reducing means, 76: control valve, 77: relief valve, 79: tank, 80: control unit, L: forward and reverse advancing position, L1: high speed switching position, L2: pressure increasing switching position, P ... Pressure, V ... Speed, V1 ... Low speed target speed, V2 ... High speed target speed, Pw ... Warm-up pressure increase target pressure, Pm ... Normal pressure increase target pressure

Claims (5)

A die cast machine comprising: an injection plunger; a drive unit for moving the injection plunger forward; and a control unit for controlling the drive unit,
The drive unit has only one linear drive system,
The control section performs (1) a low speed injection operation to advance the injection plunger at a low target speed, a high speed injection operation to advance the injection plunger at a high target speed, and forward the injection plunger at a normal target pressure. (2) the low-speed injection operation, and a worm whose injection plunger is lower than the normal pressure increase target pressure to control the drive unit to execute the injection filling operation including the normal pressure increase operation to press; And a warm-up mode for controlling the drive unit to execute a warm-up operation including at least a warm-up pressure-increasing operation of pressing up with a target pressure for increasing pressure-up.   The die casting machine according to claim 1, wherein the warm-up operation includes the high-speed injection operation.   The die-casting machine according to claim 1 or 2, wherein the controller automatically shifts to the product manufacturing mode after being activated in the warm-up mode and executing the warm-up operation. The drive unit includes one electric motor controlled by the control unit or a plurality of electric motors controlled identically by the control unit.
The control unit causes the injection plunger to be pushed forward at the warm-up pressure increase target pressure in the warm-up pressure increase operation, and the injection plunger is pressed forward at the normal pressure increase target pressure in the normal pressure-increase operation. The die casting machine according to any one of claims 1 to 3, wherein the electric motor is controlled to be controlled. The driving unit includes: an injection piston connected to the injection plunger; an injection cylinder accommodating the injection piston; hydraulic operation means for applying oil pressure to the injection cylinder; and pressure reduction means for reducing oil pressure of the injection cylinder. Have
The control unit applies an oil pressure to be the normal pressure increase target pressure to the injection cylinder in the normal pressure increase operation, and sets an oil pressure to be the normal pressure increase target pressure to the injection cylinder in the warm-up pressure increase operation. The hydraulic operating means and the pressure reducing means are controlled so as to reduce the hydraulic pressure of the injection cylinder to the warm-up pressure increase target pressure while adding the pressure to the injection cylinder, according to any one of claims 1 to 3. Die casting machine described.

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