JP2013018152A - Method for operating electromotive injection molding machine on power failure and electromotive injection molding machine - Google Patents

Abstract

An operation method of an electric injection molding machine capable of protecting a mold by supplying electric power to a servo amplifier of the electric injection molding machine and stopping in an appropriate state at the time of a power failure.
In an electric injection molding machine 1, a DC voltage is stored as power on a DC circuit (P, N) side of an AC / DC converter 2 that converts an AC voltage into a DC voltage, and the stored power is stored in a DC circuit. A power storage device 3 that can be supplied is provided. When normal, predetermined power is stored in the power storage device 3. If an abnormality in the AC voltage is detected during the mold closing process, the mold opening process, or the protruding process, the DC voltage is supplied from the power storage device 3 to complete these processes, and then the electric injection molding machine 1 is stopped. To do.
[Selection] Figure 1

Description

  The present invention provides an electric injection system that protects a mold by operating an electric injection molding machine so that power is supplied to a servo amplifier of the electric injection molding machine and stopped in an appropriate state when a power failure occurs or a supply voltage is abnormal. The present invention relates to a method of operating a molding machine, and an electric injection molding machine that implements such a method of operation.

  As is well known in the art, an injection molding machine is composed of a pair of molds, a mold clamping device for clamping these molds, an injection device for melting resin and injecting it into the mold, etc. The injection cylinder includes a screw driven in the rotation direction and the axial direction in the injection cylinder. In the electric injection molding machine, such a mold clamping device, a screw and the like are driven by servo motors provided independently of each other. The electric injection molding machine is provided with a power supply device, and this power supply device rectifies a predetermined three-phase AC voltage supplied from a power receiving facility in a factory into a DC voltage. The rectified DC voltage is supplied to a servo amplifier that drives each servo motor.

  There are various types of molds attached to the electric injection molding machine. For example, in the case of a molded product in which an appropriate draft is formed and the shape is easy to be removed, the mold can be composed of a relatively simple two-plate. However, depending on the shape of the molded product, a so-called undercut portion, in which the molded product cannot be removed from the cavity, may be formed. In such a case, a drivable core is provided in the mold. When the core is driven in conjunction with the mold clamping operation of the mold clamping device, a cavity is formed from the core and other members of the mold. After the molten resin is injected into the cavity and cooled and solidified, the core is retracted from the molded product when the core is driven in conjunction with the mold opening operation. Then, the molded product can be taken out. The mold can also be composed of so-called three plates. As is well known in the art, a mold consisting of three plates can be efficiently obtained by separating the sprue from the molded product when the molded product is removed by opening the plates in an appropriate order when the mold is opened. Can do. As described above, a mold having a core, a mold having three plates, and the like are provided with a driving member in the mold. These drive members are driven in conjunction with the mold opening / closing operation of the mold clamping device or the protrusion operation of the ejector device. However, in the event of an abnormality such as a power failure, a decrease in factory supply voltage, or a frequency fluctuation exceeding the specified value in the factory supply voltage, it cannot be guaranteed what the mold clamping device or ejector device will be in. And the drive member are not necessarily interlocked with each other. Then, expensive molds may be damaged. Accordingly, there is a demand for measures to prevent the mold from being damaged.

JP 2006-51754 A JP 2002-118967 A JP 2004-216829 A JP 2009-241287 A

  Patent Document 1 describes an electric toggle mold clamping device provided with a predetermined mold opening prevention device. The mold opening preventing device described in Patent Document 1 is provided in a cross head, and can block a ball screw that drives the cross head. Accordingly, when the mold opening preventing device is driven in the mold clamping state, the mold clamping state is maintained, and even if a power failure occurs in this state, the mold is not opened. As a result, even if a mold having a driving component such as a core is attached, the mold is not opened at an unintended timing, so that the mold can be prevented from being damaged.

  Patent Document 2 describes an electric injection molding machine provided with a predetermined power supply voltage holding device. The power supply voltage holding device is provided on the DC voltage side of the power supply device of the electric injection molding machine, and is connected in parallel with the servo amplifier that drives each servo motor. This power supply voltage holding device includes a predetermined motor, an inverter that supplies an AC voltage to the motor, and a regenerative converter that converts kinetic energy generated by the rotation of the motor into electric power and regenerates the DC voltage. During normal operation, the motor is rotated at high speed by the AC voltage supplied from the inverter. That is, it is stored as kinetic energy. When an abnormality such as a decrease in factory supply voltage occurs and a decrease in the DC voltage supplied by the power supply device is detected, the regenerative converter converts the kinetic energy generated by the rotation of the motor into electric power and regenerates the DC voltage. As a result, a stable DC voltage can be supplied to each servo amplifier. When the factory supply voltage returns to normal, stop the power supply voltage holding device. Thus, even if a temporary factory supply voltage abnormality occurs, the mold opening / closing operation, the protruding operation, and the like do not stop, and it is possible to prevent the mold including the driving member from being damaged.

  Patent Document 3 describes an electric injection molding machine including three converters that convert an AC voltage into a DC voltage. Each converter is provided with an independent DC voltage circuit, and each circuit is for a DC voltage for driving to drive the servo motor, a DC voltage for controlling to control the servo motor, and a controller for driving the controller. The direct current voltage is supplied. In the electric injection molding machine described in Patent Document 3, these DC voltage circuits are each provided with an energy storage capacitor and connected between positive and negative voltage lines. Therefore, even when the AC voltage is interrupted, the servo motor can be driven for a predetermined time by the DC voltage supplied from the energy storage capacitor. Accordingly, for example, when a power failure is detected when a mold clamping force is generated, the mold clamping device can be driven in the mold opening direction and the mold can be protected.

  Patent Document 4 is a document proposed by the present applicant and is not directly related to the present invention, but describes an electric injection molding machine provided with a power supply device. This power supply device is provided on the DC voltage side of the power supply device of the electric injection molding machine, and is connected in parallel with a servo amplifier that drives each servo motor. This power supply device has a power storage circuit composed of a coil, a capacitor, two switches, and two diodes, receives power from a DC voltage, and stores the power in a boosted state in the circuit. can do. In an injection process that requires a large amount of power in a short time, the power stored in the circuit is supplied to the DC voltage side. If it does so, the electric power supplied to an electric injection molding machine can be smoothed, and the burden of the power receiving equipment of a factory can be reduced.

  The electric injection molding machine described in Patent Document 1 or the electric injection molding machine described in Patent Document 2 can cope with abnormalities such as a power failure, a decrease in factory supply voltage, or a frequency fluctuation exceeding a specified value in the factory supply voltage. Can protect the mold. However, there are problems. For example, in the case of the electric injection molding machine described in Patent Document 1, there is no problem because the mold does not open even if a power failure occurs if the mold opening prevention device is driven. When a power failure occurs during operation, the platen apparatus may move due to inertia and damage the mold. In addition, the mold opening prevention is considered, but the protrusion operation is not considered. Therefore, in the case of a mold that has a driving part such as a core and needs to be driven in conjunction with the protruding operation, the protruding operation stops due to a power failure or the like even though the driving part is operating. And the mold will be damaged. In the case of the electric injection molding machine described in Patent Document 2, electric power can be stored as kinetic energy due to the rotation of the motor by the power supply voltage holding device, and it is converted into a DC voltage and regenerated in the event of an abnormality such as a decrease in factory supply voltage. can do. Accordingly, the operation can be continued while maintaining the DC voltage for a predetermined time, and it is possible to temporarily cope with a decrease in the supply voltage of the factory. However, there is no guarantee that the factory supply voltage will recover normally in a short time, and if the voltage does not return to normal within a predetermined time, the supply of the DC voltage is stopped. If it does so, an electric injection molding machine will stop, the mold opening-and-closing state at this time will become indefinite, and a metal mold | die cannot be protected reliably. That is, the power supply voltage holding device described in Patent Document 2 is not intended to stop the electric injection molding machine in a safe state, and therefore, if the supply voltage of the factory does not recover in a short time, the mold is damaged. there's a possibility that. In the case of the electric injection molding machine described in Patent Document 3, since electric power is stored in the capacitor for storing energy, the servo motor can be driven for a predetermined time even in the event of a power failure. It can be protected. However, depending on the energy storage capacitor, there is no guarantee that a stable DC voltage can be obtained, and the servo motor cannot always be driven reliably. When considering the capacitors for storing energy, these are merely connected between the positive and negative voltage lines, and the configuration is substantially the same as that of the conventional smoothing capacitor that smoothes the ripple voltage from the converter. As a result, the DC voltage decreases as the electric charge is released. In other words, there is no guarantee that the servo motor can be driven reliably. Further, since the DC voltage circuit is divided into three systems and independent from each other, if the voltage drops even in one system among the driving DC voltage, the control DC voltage, and the control device DC voltage, the servo motor There is also a problem that cannot be driven. This increases the possibility that the servo motor cannot be driven. That is, the electric injection molding machine described in Patent Document 3 does not guarantee that the mold can be reliably protected during a power failure. Examining the power supply device described in Patent Document 4, this power supply device is configured to supply power in place of the voltage supplied from the factory in the injection process. However, even if a power failure occurs during the mold opening / closing process and the protruding process, power is not supplied, so that the mold cannot be protected like the electric injection molding machine described in other documents.

  An object of the present invention is to provide an electric injection molding machine operating method and an electric injection molding machine that solve the above-described conventional problems or problems. Specifically, the present invention provides a power failure or supply voltage abnormality. Sometimes, the electric injection molding machine operating method for protecting the mold by operating the electric injection molding machine to supply a stable voltage power to the servo amplifier of the electric injection molding machine and stopping in an appropriate state, and It aims at providing the electric injection molding machine which enforces such an operating method.

  In order to achieve the above object, the present invention is configured as an operation method of an electric injection molding machine provided with a predetermined power storage device. Each member constituting the electric injection molding machine, such as a screw, a mold clamping device, and a molded product protruding device, is driven by a servo motor, and the servo motor is driven by a servo amplifier. The electric injection molding machine is provided with an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to a DC circuit, and electric power is supplied to each servo amplifier by the DC voltage. The power storage device is connected to a DC circuit and stores the DC voltage as power and supplies the stored power to the DC circuit. The DC voltage supplied at this time is set so that the voltage is maintained within a predetermined fluctuation range. In the electric injection molding machine equipped with such a power storage device, when the AC voltage is normal, predetermined power is stored in the power storage device. When an AC voltage abnormality is detected during the mold closing process for closing the mold, the mold opening process for opening the mold, or the protruding process for ejecting the molded product, a DC voltage is supplied from the power storage device. These steps are completed, and then the electric injection molding machine is stopped.

That is, the invention described in claim 1 stores an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, and stores and stores the DC voltage from the DC circuit as power. A power storage device that supplies power to the DC circuit, and a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, and a molded product protruding device is driven by a DC voltage from the DC circuit In the electric injection molding machine, when the AC voltage is normal, a predetermined power is stored in the power storage device, and the AC voltage is abnormal while driving the mold clamping device or the molded product protruding device. Is detected, the DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range, and the driving of the mold clamping device or the molded product protruding device is completed. Configured as an operating method for an electric injection molding machine, characterized by stopping the electric injection molding machine.
The invention according to claim 2 is an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, stores the DC voltage from the DC circuit as power, and stores the stored power. And a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, and a molded product protruding device, which is driven by a DC voltage from the DC circuit. In the electric injection molding machine, when the AC voltage is normal, a predetermined power is stored in the power storage device, and a mold opening process for opening the mold during a mold closing process for closing the mold When an abnormality in the AC voltage is detected during the projecting process of pushing out the molded product, the DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range, and the mold is closed. Extent, the die opening step or completing the projecting step, followed configured as an operating method for an electric injection molding machine, characterized by stopping the electric injection molding machine.
The invention according to claim 3 is the operation method according to claim 1 or 2, characterized in that the abnormality of the AC voltage includes a power failure, a decrease in voltage amplitude, or a frequency fluctuation exceeding a specified value. It is comprised as an operating method of an electric injection molding machine.

The invention according to claim 4 includes an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, and drives each member such as a screw, a mold clamping device, and a molded product protruding device. An electric injection molding machine in which a servo amplifier of a servo motor is driven by a DC voltage from the DC circuit, wherein the DC circuit stores a DC voltage as power and the stored power as the power A power storage device to be supplied to a DC circuit is connected, and the AC power supply is provided with a monitoring device for monitoring an AC voltage. When the AC voltage monitored by the monitoring device is normal, the power storage device has a predetermined value. Power is stored, and when the abnormality is detected in the AC voltage in the monitoring device while the mold clamping device or the molded product protruding device is being driven, the voltage is maintained within a predetermined fluctuation range. From the force storage device is supplied with a DC voltage being adapted drive to complete the clamping device or the moldings projecting device, then configured as electric injection molding machine is stopped.
The invention described in claim 5 includes an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, and drives each member such as a screw, a mold clamping device, and a molded product protruding device. An electric injection molding machine in which a servo amplifier of a servo motor is driven by a DC voltage from the DC circuit, wherein the DC circuit stores a DC voltage as power and the stored power as the power A power storage device to be supplied to a DC circuit is connected, and the AC power supply is provided with a monitoring device for monitoring an AC voltage. When the AC voltage monitored by the monitoring device is normal, the power storage device has a predetermined value. The monitoring device detects an abnormal AC voltage during the mold closing process to close the mold, the mold opening process to open the mold, or the protrusion process to eject the molded product. When the power is stored, a DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range, and the mold closing process, the mold opening process, or the protruding process is completed. The injection molding machine is configured to be stopped.
According to a sixth aspect of the present invention, in the electric injection molding machine of the fourth or fifth aspect, the AC voltage abnormality includes a power failure, a decrease in voltage amplitude, or a frequency fluctuation exceeding a specified value. Composed.
A seventh aspect of the present invention is the electric injection molding machine according to any one of the fourth to sixth aspects, wherein the power storage device includes a capacitor, a coil, and a predetermined switch. DC voltage is stored as electric power in the capacitor via the coil, and the electric power stored in the capacitor is supplied to the DC circuit via the coil when the switch is driven. The
According to an eighth aspect of the present invention, in the electric injection molding machine according to the seventh aspect, when storing electric power in the capacitor, the electric power is stored in a state of a voltage higher than a DC voltage from the DC circuit, and the capacitor When a DC voltage is supplied to the DC circuit, the power stored in the capacitor is stepped down and supplied.
According to a ninth aspect of the present invention, in the electric injection molding machine according to the seventh aspect, when storing electric power in the capacitor, the electric power is stored in a state of a voltage lower than a DC voltage from the DC circuit, and from the capacitor When a DC voltage is supplied to the DC circuit, the power stored in the capacitor is boosted and supplied.
The invention according to claim 10 is the electric injection molding machine according to any one of claims 5 to 9, wherein the DC circuit is provided with a DC / DC converter for stepping down a DC voltage of the DC circuit, The control voltage for controlling the servo amplifier is supplied from the DC / DC converter at least when an abnormality of the AC voltage is detected in the monitoring device.

  As described above, the present invention provides an AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, stores the DC voltage from the DC circuit as power, and stores the stored power as DC. An electric power storage device for supplying power to the circuit, and a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, and a molded product protruding device is driven by a DC voltage from a DC circuit It is configured as an operation method of an injection molding machine. In this operation method, when the AC voltage is normal, predetermined power is stored in the power storage device, and when the abnormality of the AC voltage is detected while driving the mold clamping device or the molded product protruding device, the voltage is predetermined. A DC voltage is supplied from the power storage device so as to be maintained within the fluctuation range of the power supply, the driving of the mold clamping device or the molded product protruding device is completed, and then the electric injection molding machine is stopped. Then, even during a power failure, a stable DC voltage is supplied, and the servo motor can operate reliably. The electric injection molding machine stops while the mold clamping device or the molded product protruding device is stopped, and no mechanical energy or potential energy that causes the members to actively move is left in these devices. Become. Therefore, even if the servo motor is not loaded, the apparatus does not start and is stable. As a result, the mold is not opened / closed or protruded regardless of the operation of the mold, so that the mold can be prevented from being damaged. According to another invention, the operation method of the electric injection molding machine is such that when the AC voltage is normal, the electric power storage device stores predetermined power, and the mold is closed during the mold closing process of closing the mold. When an abnormality in the AC voltage is detected during the mold opening process to open the mold or the protruding process to eject the molded product, the DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range. The process, the mold opening process, or the protrusion process is completed, and then the electric injection molding machine is stopped. Therefore, according to the present invention, the mold clamping device or the protruding device is stopped in a stable state, and the mold can be protected. According to another invention, in the electric injection molding machine configured to implement such an operation method, the power storage device includes a capacitor, a coil, and a predetermined switch, and the DC voltage from the DC circuit is The power is stored in the capacitor via the coil, and when the switch is driven, the power stored in the capacitor is supplied to the DC circuit via the coil. Therefore, the power storage device can be configured from a relatively simple circuit, and a stable DC voltage can be supplied. According to another invention, when power is stored in this capacitor, it is stored at a higher voltage than the DC voltage from the DC circuit, and when the DC voltage is supplied from the capacitor to the DC circuit, the power stored in the capacitor is stored. Supply with step-down. According to another invention, when power is stored in the capacitor, the voltage is stored at a lower voltage than the DC voltage from the DC circuit, and when the DC voltage is supplied from the capacitor to the DC circuit, the power stored in the capacitor is boosted. Supply. Since the electric power is boosted / decreased and supplied in this way, it can be easily controlled when the fluctuation of the DC voltage is controlled within a desired range. Further, according to another invention, the DC circuit is provided with a DC / DC converter for stepping down the DC voltage of the DC circuit, and at least when an AC voltage abnormality is detected in the monitoring device, the DC circuit is used for controlling the servo amplifier. The voltage is configured to be supplied from a DC / DC converter. Then, as long as the DC voltage is supplied, the servo amplifier control voltage is surely supplied, and it is guaranteed that the servo motor can be driven.

In an electric injection molding machine provided with an electric power storage device concerning this embodiment, it is a top view showing typically a connection state of an electric power storage device and each servo amplifier. It is a circuit diagram which shows the power storage circuit of the power storage apparatus which concerns on this Embodiment. It is a figure which shows typically the effect | action of the power storage circuit which concerns on this Embodiment, The (a), (b) is the operation state of the circuit in the case of storing electric power in the power storage circuit, (c), (D) is operation | movement explanatory drawing explaining the operation state of a circuit in the case of supplying the stored electric power from a positive terminal and a negative terminal, respectively. 5 is a flowchart showing an operation method when an abnormality in an AC voltage is detected in the electric injection molding machine according to the present embodiment. It is a graph which shows the driving | running method when the abnormality of alternating voltage is detected in the electric injection molding machine which concerns on this Embodiment. It is a circuit diagram which shows the power storage circuit of the power storage apparatus which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below. The electric injection molding machine 1 according to the present embodiment also rectifies the three-phase AC voltage supplied from the three-phase AC power supply PW and supplies the DC voltage to the servo amplifier, similarly to the conventionally known electric injection molding machine. It is like that. Accordingly, the electric injection molding machine 1 according to the present embodiment is also provided with an AC / DC converter 2 as shown in FIG. 1, and the AC / DC converter 2 is connected to the three-phase AC power source PW and also has a DC. Connected to circuits P and N. Although not described in detail, the AC / DC converter 2 is a converter that converts a three-phase AC voltage into a DC voltage, and includes a conventionally known diode rectifier circuit, PWM converter, and the like. Although not shown in FIG. 1, a smoothing capacitor is connected between the positive and negative voltage lines P and N of the DC circuit inside the AC / DC converter 2 so that the DC voltage is smoothed. .

  Servo motors for driving each device of the electric injection molding machine 1, that is, servo motor SM1 for driving the screw in the axial direction, servo motor SM2 for driving in the rotational direction, servo motor SM3 for driving the mold opening / closing device, and ejector pins are driven. Servo motors SM4,... Are driven by corresponding servo amplifiers SA1, SA2,. These servo amplifiers SA1, SA2,... Are connected at their positive terminals to the positive voltage lines P of the DC circuits P, N, respectively. Accordingly, a DC voltage is supplied from the AC / DC converter 2 to the servo amplifiers SA1, SA2,.

  The electric injection molding machine 1 according to the present embodiment is provided with a device that can store a DC voltage as power and can supply the stored power as a DC voltage to the DC circuits P and N, that is, a power storage device 3. It has been. As a result, even when the three-phase AC voltage is abnormal, such as a power failure, the servo motors SM1,. The power storage device 3 is connected to the positive voltage line P. The power storage device 3 will be described in detail later.

  The electric injection molding machine 1 according to the present embodiment is also provided with a control device 5 for controlling each device, but the power for driving the control device 5 is stably supplied even during a power failure. In addition, the supply means is doubled. Specifically, power can be supplied from both the AC voltage from the three-phase AC power supply PW and the DC voltage from the power storage device 3. That is, the control power supply AC / DC converter 6 is provided in the three-phase AC power supply PW, and the control power supply DC / DC converter 7 is provided in the positive voltage line P of the power storage device 3. It has been converted. The voltage lines from these converters 6 and 7 are input to the changeover switch SW. The change-over switch SW may be composed of any switch such as a semiconductor switch or a mechanical switch, and is operated by a signal from the control device 5. With this changeover switch SW, the drive power supply destination of the control device 5 is appropriately selected from the control power supply AC / DC converter 6 or the power supply DC / DC converter 7.

  In the present embodiment, an AC voltage monitoring device 9 is provided on the AC circuit side of the AC / DC converter 2. This device is connected to the control device 5 by a signal line, and monitors the three-phase AC voltage, and if an AC voltage abnormality such as a power failure, a voltage drop, or a frequency fluctuation exceeding a specified value is detected, the control device 5 is notified of the abnormality. It has come to be. The frequency fluctuation exceeding the specified value means a state where the frequency is unstable such that the frequency fluctuates over a predetermined ratio, for example, 5%.

  The power storage device 3 according to the present embodiment will be described in detail. As shown in FIG. 2, the power storage device 3 includes a power storage circuit 11 and a control circuit 12 that controls the power storage circuit 11. The power storage circuit 11 is connected to the DC circuits P and N, and is connected to the positive terminal P connected to the positive voltage line of the DC circuits P and N and the negative voltage line, that is, the grounded voltage line. Negative terminal N. The power storage circuit 11 includes these positive terminal P, negative terminal N, one capacitor C, one coil L, and first and second switch circuits SW1 and SW2. The first switch circuit SW1 includes a first transistor Tr1 and a first diode D1, and the second switch circuit SW2 includes a second transistor Tr2 and a second diode D2. For example, an electric double layer capacitor is used as the capacitor C, and an insulated gate bipolar transistor, that is, an IGBT is used as the transistors Tr1 and Tr2. The power storage circuit 11 will be described in more detail. The negative terminal N, the positive terminal P, and the coil L connected to the positive terminal P are shared by the first and second loop circuits LP1 and LP2. That is, the first loop circuit LP1 is a circuit in which a negative terminal N, a positive terminal P, a coil L, a first switch circuit SW1 and a capacitor C are connected in series, and the second loop circuit LP2 is The negative terminal N, the positive terminal P, the coil L, and the second switch circuit SW2 are connected in series. Each of the switch circuits SW1 and SW2 is a circuit in which one diode and one transistor are connected in parallel, and a current flows freely in one direction, but the transistor is turned on in the opposite direction. That is, it is a circuit that controls the flow of current that flows only when switching. Specifically, the first switch circuit SW1 is connected so that the first diode D1 flows a current from the positive terminal P to the negative terminal N. When the first transistor Tr1 is turned on, the current flows in the reverse direction. Is connected in parallel with the first diode D1. The second switch circuit SW2 is connected so that the second diode D2 flows current from the negative terminal N to the positive terminal P, and the second transistor Tr2 flows current in the reverse direction when turned on. And connected in parallel with the second diode D2.

  The operation of the power storage circuit 11 according to the present embodiment will be described with reference to FIG. In the power storage circuit 11, in the initial state, the first diode D1 is provided in a direction in which a current flows freely from the positive terminal P to the capacitor C. Therefore, the power storage circuit 11 is provided on the positive (+) electrode side of the capacitor C. The potential is equal to the potential of the positive terminal P. Therefore, the storage voltage V2 is equal to the voltage V1 between the positive and negative terminals P and N. A case where power is stored from this state will be described. As shown in FIG. 3A, the second transistor Tr2 is switched, that is, turned on. Then, current flows as shown by an arrow YA. When a predetermined time elapses after the current flows, magnetic energy is accumulated in the coil L. The second transistor Tr2 is turned off. Then, as shown in FIG. 3A, a high voltage electromotive force in the direction of the arrow YB is instantaneously generated in the coil L by the magnetic energy accumulated in the coil L. Due to the generated electromotive force, a current flows through the first diode D1 as indicated by an arrow YC, and power is stored in the capacitor C. That is, the DC voltage is boosted by the action of the coil L and stored in the capacitor C. Hereinafter, when ON / OFF of the second transistor Tr2 is repeated, electric power is stored in the capacitor C, and the storage voltage V2 becomes higher than the inter-terminal voltage V1.

The case where the stored power is output to the outside as a DC voltage in the power storage circuit 11 will be described. When power is stored in the capacitor C by the operation of the previous section, the storage voltage V2 and the inter-terminal voltage V1 are:
V2> V1
This relationship is established. When the first transistor Tr1 is turned on in this state, a current flows in the direction of the arrow YD as shown in FIG. When a current flows, magnetic energy is accumulated in the coil L, and an electromotive force is generated in the coil L in the direction of the arrow YE. That is, the electromotive force of the coil L shares the potential difference between the storage voltage V2 and the terminal voltage V1. Next, the first transistor Tr1 is turned off. Then, as shown in FIG. 3D, the high voltage electromotive force in the direction of the arrow YF is applied to the coil L so that the current of the coil L is maintained by the magnetic energy accumulated in the coil L. Due to the electromotive force generated in the coil L, a current flows as indicated by an arrow YG via the second diode D2. As described above, when the first transistor Tr1 is repeatedly turned on and off, a predetermined DC voltage can be output from the inter-terminal voltage V1 to the outside. That is, power can be supplied. When power is supplied from the power storage circuit 11 to the DC circuits P and N, ON / OFF of the transistor Tr1 is controlled so that the fluctuation of the DC voltage is maintained within 5%. That is, the high storage voltage V2 is substantially stepped down to the inter-terminal voltage V1 and supplied. As described above, the AC / DC converter 2 connected to the positive and negative terminals P and N is provided with the smoothing capacitor. This smoothing capacitor also suppresses fluctuations in the inter-terminal voltage V1.

  The electric injection molding machine 1 is also attached with a mold having driving parts. For example, a die having a core, a die having three plates, and the like are attached. These molds need to drive the drive parts in conjunction with the mold opening / closing operation of the mold clamping device or the projection operation of the molded product projecting device. When stopped, the mold will be damaged if only the drive member operates alone. Since the electric injection molding machine 1 according to this embodiment includes the power storage circuit 11, even if an abnormality such as a power failure occurs, the mold clamping device and the molded product protruding device are driven until they are in an appropriate state. It has become. If it is considered that the power is supplied only for a predetermined time in the case of an abnormality, the mold can be reliably prevented from being damaged. An operation method of the electric injection molding machine 1 according to the present embodiment will be described.

  An operation method when the three-phase AC voltage is normal will be described. In this case, the AC voltage monitoring device 9 detects a three-phase AC voltage. The changeover switch SW is in a standard state and is switched to the control power supply AC / DC converter 6 side. The three-phase AC voltage from the three-phase AC power source PW is converted into a predetermined DC voltage by the control power source AC / DC converter 6, and the control device 5 is driven by this DC voltage. The three-phase AC voltage is converted into a DC voltage by the AC / DC converter 2 and supplied to the DC circuits P and N. Each servo amplifier SA1, SA2,... Generates an AC voltage and drives predetermined servo motors SM1, SM2,. That is, the injection shaft is driven in the injection process, the plasticization shaft is driven in the metering (plasticization) process, the mold opening / closing shaft is driven in the mold opening process and the mold closing process, and the protrusion shaft is driven in the protrusion process. Thus, each step of the molding cycle is performed.

  In the electric injection molding machine 1 according to the present embodiment, power is stored in the power storage device 3 when the three-phase AC voltage is normal as described above. A command is issued from the control device 5 to the power storage device 3. The control circuit 12 of the power storage device 3 repeats ON / OFF of the second transistor Tr2 of the power storage circuit 11. As described above, predetermined power is stored in the capacitor C in response to the supply of the DC voltage from the DC circuits P and N. When the storage voltage V2 reaches a predetermined voltage, the driving of the second transistor Tr2 is stopped.

  The operation method at the time of a power failure or when an abnormality such as a voltage drop of a three-phase AC voltage or a frequency fluctuation exceeding a specified value is described. As shown in FIG. 4, when these events occur, an abnormality is detected in the AC voltage monitoring device 9 and notified to the control device 5 (step S1). The control device 5 switches the changeover switch SW. Then, the DC voltage from the DC circuits P and N is converted into a predetermined voltage by the control power source DC / DC converter 7 and supplied to the control device 5 as drive power (step S2). Even if an abnormality occurs in the supply of the three-phase AC voltage, the AC / DC converter 2 is provided with a smoothing capacitor, so that power can be supplied for a short time. The control device 5 determines the type of process currently being performed in the electric injection molding machine 1 (step S3). More specifically, as schematically shown by a “process management” block and a “process determination & completion confirmation” block in FIG. 1, a process management process for managing each process in the control device 5. Then, the process determination and completion confirmation process for obtaining information from the process management process and performing process determination and process completion confirmation is executed. From the process management process, information related to the process currently being executed in the electric injection molding machine 1 is sent to the process determination & completion confirmation process, and a completion notice is sent when the process is completed. Therefore, in the process determination & completion confirmation process, it is possible to determine the type of process currently being performed. If the current process thus determined is a mold closing process, a mold opening process for driving the mold clamping device, or a projecting process for driving the molded product projecting apparatus, do not interlock with the mold. If the mold clamping device or the molded product protruding device is driven, the mold may be damaged. If it is determined that these steps are performed, the control device 5 outputs a power supply command to the power storage device 3. The control circuit 12 of the power storage device 3 repeats ON / OFF of the first transistor Tr1 of the power storage circuit 11. Then, the power stored in the power storage device 3 is supplied to the DC circuits P and N as a DC voltage (step S4). The control device 5 completes the process currently being performed. That is, if the mold closing process is being performed, the mold closing process is completed, and if the mold opening process is being performed, the mold opening process is completed. Specifically, in the process determination & completion confirmation process, the process is continued until a completion notification that the current process is completed is received, and when the completion notification is received, the process proceeds to the next step (step S5). After confirming the completion of the process, the control device 5 outputs a power supply stop command to the power storage device 3. The power storage device 3 stops the supply of the DC voltage (step S6). All devices of the electric injection molding machine 1 are stopped (step S7). If it is determined in step S3 that the process currently being performed is another process, that is, if an injection process, a pressure holding process, or a metering (plasticizing) process is being performed, there is no possibility of damaging the mold. In this case, the process proceeds to step S7 and all the devices of the electric injection molding machine 1 are stopped. FIG. 5 shows whether or not the power supply of the power storage device 3 is performed when a power failure occurs in each step of the molding cycle. The timing at which a power failure occurs is indicated by an arrow, and no power is supplied from the power storage device 3 when a power failure occurs in the injection process, the pressure holding process, and the metering (plasticization) process. However, when a power failure occurs in the mold closing process, the mold opening process, and the protruding process, electric power is supplied from the power storage device 3 until these processes are completed.

  The power storage device 3 according to the present embodiment can supply power even when a power failure occurs or when the three-phase AC voltage is abnormal. As a result, power supply from the three-phase AC power supply PW can be smoothed. In the molding cycle, the maximum power is consumed in a short time in the injection process, but the power consumed in other processes is relatively small. Therefore, if the maximum power during the injection process is supplied by the power storage device 3, the power supply from the three-phase AC power supply PW can be smoothed, and the AC / DC converter 2 can also be configured with a small capacity. . Even if a large amount of power is supplied from the power storage device 3 in the injection process, the subsequent processes are the pressure holding process and the metering (plasticizing) process, which are relatively long and cause power outages. However, it is not necessary to supply power. The power storage device 3 can store sufficient power in these steps.

  The electric injection molding machine 1 according to the present embodiment can be implemented in various forms without being limited to the above embodiment. For example, in the above embodiment, the power storage circuit 11 is described as boosting and storing the voltage when storing the DC voltage from the DC circuit in the capacitor as power, and decreasing and supplying the voltage when supplying it. However, power can be stored and supplied in different ways. FIG. 6 shows a power storage circuit 11 ′ according to the second embodiment that stores and supplies power in a different manner. Similarly to the power storage circuit 11 according to the previous embodiment, the power storage circuit 11 ′ according to the second embodiment also has positive and negative terminals P and N, a capacitor C ′, a coil L ′, and first and second switches SW1. ', SW2'. Two circuits are also formed in the power storage circuit 11 ′, and one circuit is a circuit in which the first switch circuit SW1 ′, the positive and negative terminals P and N, and the second switch circuit SW2 ′ are connected in series. The other circuit is a circuit in which a capacitor C ′, a coil L ′, positive and negative terminals P, N, and a second switch circuit SW2 ′ are connected in series. That is, the positive and negative terminals P and N and the second switch circuit SW2 'are common. The first switch circuit SW1 ′ is composed of a first transistor Tr1 ′ and a first diode D1 ′ connected in parallel. The first diode D1 ′ conducts a current from the negative terminal N to the positive terminal P. When the first transistor Tr1 ′ is turned on, the first transistor Tr1 ′ is provided in such a direction that current flows in the reverse direction. The second switch circuit SW2 ′ is also composed of a second transistor Tr2 ′ and a second diode D2 ′ connected in parallel, and the second diode D2 ′ conducts current from the negative terminal N to the positive terminal P. When the second transistor Tr2 ′ is turned on, the second transistor Tr2 ′ is provided in such a direction that current flows in the opposite direction. When power is stored in the power storage circuit 11 ′ according to the second embodiment, the second transistor Tr <b> 2 ′ is turned on / off. When the second transistor Tr2 ′ is ON, the current flows through the positive terminal P, the second transistor Tr2 ′, the coil L ′, the capacitor C ′, and the negative terminal N. When the second transistor Tr2 ′ is OFF, the current is the coil L ′ and the capacitor C ′. , Flows through the first diode D1 ′. As a result, electric power can be stored in the capacitor C '. At this time, the storage voltage of the capacitor C ′ is lower than the voltage between the positive and negative terminals P and N. When a DC voltage is supplied from the power storage circuit 11 ', the first transistor Tr1' is turned on / off. When the first transistor Tr1 ′ is ON, a current flows through the capacitor C ′, the coil L ′ and the first transistor Tr1 ′. When the first transistor Tr1 ′ is OFF, the current is the capacitor C ′, the coil L ′, and the second diode D2 ′. , Flow through the positive and negative terminals P and N. As a result, a DC voltage can be supplied. At this time, the storage voltage from the capacitor C ′ is boosted by the coil L ′ and supplied to the DC voltage. In this way, the power storage circuit 11 ′ according to the second embodiment can supply a stable DC voltage similarly to the power storage circuit 11 according to the previous embodiment.

  Other variations are possible and the power storage device 3 need not be configured to store power in a capacitor. For example, electric power may be stored in a storage battery, or a motor or the like may be rotated and stored as kinetic energy as in the device described in Patent Document 2. Alternatively, it may be configured as a device described in Japanese Patent Application Laid-Open No. 2010-058317. In this device, a current is passed through a coil provided inside to store electric power as electromagnetic energy, and a predetermined switch When is driven, electric power is converted into a DC voltage and can be supplied to the outside. In short, the power storage device 3 may be configured so that the stored power or kinetic energy can be supplied as a DC voltage, and the DC voltage is configured so that the fluctuation of the voltage is maintained within a predetermined range. Other than the power storage device 3 can also be modified. For example, in the present embodiment, it has been described that the driving power of the control device 5 is supplied from both the three-phase AC voltage from the three-phase AC power supply and the DC voltage from the DC circuit. If a backup device is provided, it can be configured to be supplied only from a three-phase AC power source.

DESCRIPTION OF SYMBOLS 1 Electric injection molding machine 2 AC / DC converter 3 Power storage apparatus 5 Control apparatus 6 Control power supply AC / DC converter 7 Control power supply DC / DC converter 9 AC voltage monitoring apparatus 11 Power storage circuit 12 Control circuit P Positive terminal N Negative Terminal PW Three-phase AC power supply L Coil D1, D2 Diode C Capacitor SW1, SW2 First and second switches SA1, SA2, SA3, SA4 Servo amplifier SM1, SM2, SM3, SM4 Servo motor

Claims (10)

An AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, and a power storage device that stores the DC voltage from the DC circuit as power and supplies the stored power to the DC circuit In an electric injection molding machine in which a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, and a molded product protruding device is driven by a DC voltage from the DC circuit,
When the AC voltage is normal, the power storage device stores predetermined power,
When an abnormality of the AC voltage is detected while driving the mold clamping device or the molded product protruding device, a DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range, and the mold clamping device or An operation method of an electric injection molding machine, wherein driving of the molded product protruding device is completed, and then the electric injection molding machine is stopped. An AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to the DC circuit, and a power storage device that stores the DC voltage from the DC circuit as power and supplies the stored power to the DC circuit In an electric injection molding machine in which a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, and a molded product protruding device is driven by a DC voltage from the DC circuit,
When the AC voltage is normal, the power storage device stores predetermined power,
When an abnormality in the AC voltage is detected during the mold closing process for closing the mold, the mold opening process for opening the mold, or the protruding process for projecting the molded product, the voltage is maintained within a predetermined fluctuation range. An electric injection molding machine characterized in that a DC voltage is supplied from the power storage device to complete the mold closing process, the mold opening process, or the protruding process, and then the electric injection molding machine is stopped. how to drive.   3. The operation method according to claim 1, wherein the AC voltage abnormality includes a power failure, a decrease in voltage amplitude, or a frequency fluctuation exceeding a specified value. An AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to a DC circuit, and a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, a molded product protruding device, etc. An electric injection molding machine adapted to be driven by a DC voltage from a circuit,
The DC circuit is connected to a power storage device that stores DC voltage as power and supplies the stored power to the DC circuit,
The AC power supply is provided with a monitoring device for monitoring the AC voltage,
When the alternating voltage monitored in the monitoring device is normal, predetermined power is stored in the power storage device,
When an abnormality in the AC voltage is detected in the monitoring device while the mold clamping device or the molded product protruding device is being driven, a DC voltage is supplied from the power storage device so that the voltage is maintained within a predetermined fluctuation range. The electric injection molding machine is characterized in that driving of the mold clamping device or the molded product protruding device is completed, and thereafter the electric injection molding machine is stopped. An AC / DC converter that rectifies an AC voltage from an AC power source and supplies a DC voltage to a DC circuit, and a servo amplifier of a servo motor that drives each member such as a screw, a mold clamping device, a molded product protruding device, etc. An electric injection molding machine adapted to be driven by a DC voltage from a circuit,
The DC circuit is connected to a power storage device that stores DC voltage as power and supplies the stored power to the DC circuit,
The AC power supply is provided with a monitoring device for monitoring the AC voltage,
When the alternating voltage monitored in the monitoring device is normal, predetermined power is stored in the power storage device,
If an abnormality in the AC voltage is detected in the monitoring device during the mold closing process for closing the mold, the mold opening process for opening the mold, or the protruding process for ejecting the molded product, the voltage is set to a predetermined value. A direct-current voltage is supplied from the power storage device so as to be maintained in the fluctuation range, and the mold closing process, the mold opening process, or the protruding process is completed, and then the electric injection molding machine is stopped. An electric injection molding machine characterized by that.   6. The electric injection molding machine according to claim 4, wherein the AC voltage abnormality includes a power failure, a decrease in voltage amplitude, or a frequency fluctuation exceeding a specified value.   The electric injection molding machine according to any one of claims 4 to 6, wherein the power storage device includes a capacitor, a coil, and a predetermined switch, and a DC voltage from the DC circuit passes through the coil. Electric injection molding characterized in that when stored in the capacitor as electric power and the switch is driven, the electric power stored in the capacitor is supplied to the DC circuit via the coil. Machine power storage device.   8. The electric injection molding machine according to claim 7, wherein when storing electric power in the capacitor, the electric power is stored in a higher voltage state than the DC voltage from the DC circuit, and the DC voltage is supplied from the capacitor to the DC circuit. A power storage device for an electric injection molding machine, wherein the power stored in the capacitor is stepped down and supplied.   8. The electric injection molding machine according to claim 7, wherein when storing electric power in the capacitor, the electric power is stored in a state lower than the DC voltage from the DC circuit, and when supplying the DC voltage from the capacitor to the DC circuit. A power storage device for an electric injection molding machine, wherein the power stored in the capacitor is boosted and supplied.   The electric injection molding machine according to any one of claims 5 to 9, wherein the DC circuit is provided with a DC / DC converter for stepping down a DC voltage of the DC circuit, and at least an abnormality of the AC voltage in the monitoring device. When the voltage is detected, a control voltage for controlling the servo amplifier is supplied from the DC / DC converter.

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