JP4408134B2 - Hydraulic supply device, injection molding machine, and control method of hydraulic actuator device using the same - Google Patents

Description

  The present invention relates to a hydraulic pressure supply device for supplying hydraulic fluid having a predetermined flow rate and / or pressure to various hydraulic actuator devices such as a hydraulic cylinder and a hydraulic motor, and further, a hydraulic actuator using the hydraulic pressure supply device. It relates to a method for controlling the drive of a device.

  In injection molding devices, press molding devices, etc., hydraulic fluid is guided from various hydraulic actuators to various hydraulic actuator devices, and the hydraulic fluid flow rate and / or pressure is controlled on the hydraulic pressure supply device side to control the hydraulic actuator device operating speed. Torque is controlled. For example, in an injection molding machine for plastic molding, an injection cylinder for injecting a raw material resin into a mold cavity, a hydraulic motor for rotating a metering screw conveyor for feeding the raw material resin into the injection cylinder, and a mold are closed under pressure. Hydraulic actuator devices are used in various operating parts such as a clamping cylinder for ejecting and an ejector cylinder for taking out a molded product from a cavity of a mold.

  Industrial machines using such hydraulic equipment are widely used, and the sizes of products produced thereby are diversifying. Taking an injection molding device as an example, from a relatively small product such as an electronic component or a casing of a portable electronic terminal device, to a medium-sized product such as an interior panel component or container of a vehicle or an aircraft, or a larger size. As the size of the products to be molded diversifies, the molds become larger. However, in an industrial machine that uses these hydraulic devices, when the size of the mother machine increases, it is necessary to increase the flow rate and pressure of hydraulic oil to be supplied from the hydraulic supply device accordingly. Therefore, as a manufacturer of hydraulic supply devices, in general, there are several types of hydraulic supply devices with several rated capacities that have been drastically enlarged pump units and their drive motors in order to cope with the larger size of the main unit. It is necessary to prepare it.

  FIG. 7 is an explanatory diagram showing a configuration concept of a conventional hydraulic pressure supply apparatus serialized in several types of rated capacities as described above using a hydraulic circuit diagram. As shown in FIG. 7, each of the hydraulic pressure supply devices 70a, 70b, and 70c includes a fixed capacity type or variable capacity type pump unit and a variable speed AC servo motor for driving the pump unit, and detects the rotation speed of the servo motor. The flow rate and pressure of the hydraulic fluid discharged from the pump unit are converted into operation command signals (speed command and pressure command) by controlling with the speed servo control and torque servo control system by feedback signals from the pressure detector (encoder) and pressure detector. This is a servo-controlled hydraulic power unit that is controlled to follow. As described above, conventionally, several types of hydraulic power units 70a to 70c having a pump capacity are prepared in series, and a hydraulic power unit having a pump capacity suitable for the size of the mother machine is selected. However, such a series is not only a factor that creates excess inventory for manufacturers of hydraulic supply devices, but it is also difficult for users to use in a high-speed rotation range with a large capacity pump unit, A large servo motor causes various inconveniences such as being unsuitable for use in a high-speed rotation range.

Therefore, for example, Patent Document 1 proposes that when a large capacity is required, a plurality of hydraulic pump devices are connected in parallel to supply the combined discharge flow rate to the load side.
Japanese Unexamined Patent Publication No. 63-013903

  The proposal disclosed in Patent Document 1 is for supplying hydraulic oil having a constant pressure to a load. The discharge pressure of each pump device is maintained at a constant pressure by a relief valve, while lowering the lower limit of the hydraulic oil. The flow rate and the upper limit flow rate are detected by a flow switch, and the operation and non-operation of the second and subsequent pump devices are selected. However, in this method, a time delay is unavoidably caused when the operation is switched, and it is pointed out that the response is low. This is because it is necessary to wait for detection of the upper limit and the lower limit of the flow rate by the flow switch after being limited to a constant discharge pressure by the relief valve.

  As one method for improving the responsiveness, a combined discharge flow rate method in which a plurality of pump devices are operated in parallel without using a relief valve or a flow switch is also possible. However, in that case, it is necessary to provide a check valve individually in the discharge line of each pump device in order to prevent the reverse flow of the hydraulic oil into the pump device that has not been activated among the plurality of pump devices. An example is shown in FIG. As shown in FIG. 8, when hydraulic fluid is supplied to the injection molding machine 90 by a plurality of hydraulic pump devices 80a to 80d, except for the hydraulic pump device 80a that is always started first, other hydraulic pump devices 80b to 80b A check valve 82 is provided at each of the discharge ports 81 of d to prevent hydraulic oil from another hydraulic pump device from flowing back when any of these hydraulic pump devices 80b to 80d is not activated. There was a need.

  The reason is that the fluid energy from the pump device that was started even a little earlier flows into the pump device that has not been started, as long as the electric motors of a plurality of hydraulic pump devices do not start simultaneously at the time of startup of the device, This is because the pump unit of the pump device that has not been activated operates as a hydraulic motor. As a result, there is a concern that the motor connected to the pump unit that now operates as a hydraulic motor is forcibly reversely rotated, resulting in equipment burnout. Such a phenomenon occurs even when only one hydraulic pump device is not started for some reason. In practice, it is necessary to provide check valves 82 at the discharge ports 81 of all the hydraulic pump devices 80a to 80d. There is.

  However, if it is recalled that the hydraulic pump device side needs to discharge the hydraulic oil to the reservoir when performing the pressure release operation of the load side hydraulic actuator device, the circuit system shown in FIG. It is clear that the presence is at the expense of responsiveness during the depressurization operation.

  As described above, in large-capacity hydraulic pump devices, the pump unit itself has difficulties in use in the high-speed rotation range, and many servo motors cannot be used in the high-speed rotation range as the size increases, and servos Problems have been pointed out such as slow control responsiveness and worsening the cost balance between performance and workload.

  An object of the present invention is to provide a hydraulic pressure supply device that maintains high responsiveness and can easily cope with an increase in the size of a mother machine, and a drive control method for a hydraulic actuator device using the same. Such a hydraulic pressure supply device must have a configuration that is unlikely to cause damage or malfunction of the electric motor or the control unit even if an unexpected situation occurs on the load side.

  In order to solve this object, a hydraulic pressure supply device according to the present invention includes a plurality of hydraulic pump devices each including a variable speed electric motor and a pump unit driven by the electric motor; the discharge direction with respect to the discharge port of each pump unit In addition, the flow of the hydraulic oil is directly communicated so as to allow the passage of the hydraulic oil with respect to both directions of the suction direction, and the flow of the hydraulic oil discharged from the individual pump units is merged and led to the hydraulic actuator device on the load side or vice versa. Hydraulic oil passages for diverting the flow of hydraulic oil returned from the actuator device on the load side to the respective pump units; and each hydraulic pump so that each pump unit operates with the same operating characteristics Control means for controlling the rotation speed of the motor of the apparatus in synchronization with each other is provided.

  According to a preferred embodiment of the present invention, each variable speed motor is constituted by a servo motor combined with a servo control unit for controlling the rotational speed and a rotational speed detector. The control means controls each servo control unit of each hydraulic pump device, and in each hydraulic pump device, a feedback signal corresponding to the rotation speed of the servo motor detected by the rotation speed detector is given to the servo control unit. Thereby, each servo control unit servo-controls the rotation speed of each servo motor so as to follow a general control command given from the control means. The hydraulic oil passage that communicates in common with the discharge port of the pump unit of each hydraulic pump device is provided with one pressure detector common to all the hydraulic pump devices, and the hydraulic fluid in the hydraulic oil passage is provided by this pressure detector. Pressure is detected. The detection signal from this pressure detector is given to the control means as a feedback signal, whereby the mechanical output of the servo motors of all the hydraulic pump devices through all the servo control units belonging to the overall control of the control means. Torque is servo controlled in common.

  According to another preferred embodiment of the present invention, the hydraulic pressure supply device includes a pressure detector that detects the pressure of the hydraulic oil in the hydraulic oil passage, and a detection signal from the pressure detector indicates an abnormal pressure value. Drive stop means for stopping the drive of all the hydraulic pump devices associated with the hydraulic oil passage when shown is further provided.

  According to still another preferred embodiment of the present invention, the hydraulic pressure supply device includes any one of a rotation speed detector that individually detects the rotation speed of the electric motor of each hydraulic pump apparatus, and the rotation speed detector. Drive stop means is further provided for stopping the drive of all the hydraulic pump devices when a detection signal indicating abnormal rotation of the electric motor in at least one hydraulic pump device is output.

  The present invention also provides a method for selectively controlling the operation of a plurality of hydraulic actuator devices connected to the load side through the hydraulic oil passage using the hydraulic pressure supply device as described above. In this method, the number of revolutions of each electric motor belonging to two or more hydraulic pump devices selected in advance according to the load capacity of the hydraulic actuator device connected to the load side is controlled in synchronization with each other by the control means. The

  In this case, according to one preferred variant embodiment, at least a first hydraulic actuator device and a second hydraulic actuator device are prepared as the hydraulic actuator device, and either one or both of these hydraulic actuator devices is a switching valve. Rotation of each electric motor belonging to the number of hydraulic pump devices that is selectively connected to the working fluid passage by a device and corresponds to the load capacity of the hydraulic actuator device connected to the hydraulic oil passage according to the selection by the switching valve device The number is controlled by the control means.

  According to another preferred variant embodiment, a first hydraulic fluid passage and a second hydraulic fluid passage connected to different hydraulic actuator devices are prepared as the hydraulic fluid passages, and the hydraulic fluid passages are provided. Discharge ports of at least two or more hydraulic pump devices belonging to at least two of the hydraulic pump devices are selectively communicated to either one or both by an on-off valve device, and the first and / or the first and / or Alternatively, the number of revolutions of each electric motor belonging to the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator device connected to the second hydraulic oil passage is controlled by the control means.

  According to the present invention, each of the hydraulic pump devices may be small, and the required number of hydraulic pump devices are selectively operated in parallel according to the capacity required on the load side, so that the high response of the small hydraulic pump device is high. Can be obtained, and the advantage that it can easily cope with an increase in the size of the mother machine can be enjoyed. In addition, even if an unexpected situation occurs on the load side, it is easy to take measures to prevent the motors and servo control units of each hydraulic pump device from being damaged or malfunctioning.

  The hydraulic pressure supply device according to the present invention functions as a large-capacity hydraulic pressure supply device corresponding to the increase in the size of the mother machine while maintaining the high responsiveness of each individual hydraulic pump device itself.

  That is, in the hydraulic pressure supply device according to the present invention, the rotational speeds of the motors belonging to two or more hydraulic pump devices selected in advance according to the load capacity of the hydraulic actuator device connected to the load side are mutually controlled by the control means. It is controlled synchronously. For example, when the motors of a plurality of hydraulic pump devices start rotating in synchronization with an activation command signal given from the control means, the hydraulic oil discharged from the pump units of these hydraulic pump devices is discharged from the discharge port of each pump unit. Are joined by hydraulic fluid passages that are directly communicated with each other, and are led to a hydraulic actuator device on the load side with a combined flow rate. In this case, the operation of each pump unit is servo-controlled by the control means, and the responsiveness of the entire hydraulic pressure supply device at that time maintains a high responsiveness specific to the individual hydraulic pump device itself. Therefore, according to the present invention, it is not necessary to prepare several kinds of rated performance hydraulic supply devices in preparation for the size change on the mother machine side such as an injection molding machine. The hydraulic supply device according to the present invention may be configured by combining only the number corresponding to the load capacity required on the mother machine side, and the manufacturer of the hydraulic supply device has immeasurable benefits in various areas such as manufacturing, maintenance, inventory management, etc. You can enjoy it. The hydraulic pump device may be of a type adapted to forward / reverse bidirectional rotation. In this case, for example, the hydraulic oil is released from the hydraulic system on the load side under the control of the pump speed by the control means. Can be done efficiently. That is, when the motors of the plurality of hydraulic pump devices are reversely rotated by the control means, the flow of hydraulic oil returned from the load-side actuator device is divided by the hydraulic oil passage and is individually sucked into each pump unit. . Also in this case, the operation of each pump unit is servo-controlled by the control means, and the responsiveness of the entire hydraulic pressure supply device at that time maintains a high responsiveness specific to the individual hydraulic pump device itself.

  In the hydraulic pressure supply device of the present invention, various types of electric motors capable of controlling the rotation speed can be used as electric motors for driving the pump units of the hydraulic pump device. Although an internal combustion engine can be used instead of the electric motor, it is preferable to use the electric motor for accurate control of the rotational speed. Examples of such an electric motor include various DC or AC synchronous motors such as an inverter motor, a stepping motor, and a servo motor.

  For example, a stepping motor has a feature that the electrical angle of rotation is proportional to the number of pulses by digital input, but the response speed is slower than other motors, and a circuit (driver) for generating pulses, rotation, It is necessary to separately prepare a control device for controlling.

  The servo motor has a function to servo-control the mechanical output (rotation speed, thrust torque, position) according to the operation command according to the feedback signal from the rotation speed detector such as a rotary encoder and other external sensors. A product that is a motor and is a combination of a DC or AC motor and a servo control unit and sensor for controlling the rotational speed is commercially available. Such a commercially available servo motor product has a function to measure the state of the controlled object and automatically perform correction control in comparison with the reference value based on the operation command. In addition to the encoder and current detector, feedback input is also available. Since it corresponds also to signals from various external sensors such as position sensors, it can be suitably used as an electric motor and control means for driving the pump unit of the hydraulic pump device in the hydraulic pressure supply device of the present invention.

  In the hydraulic supply device of the present invention, the pump unit of the hydraulic pump device may be any unit that discharges / sucks hydraulic oil at a flow rate corresponding to the rotational speed of the electric motor. For example, a fixed displacement type or a variable displacement type piston pump or vane pump Can be used.

  In the hydraulic supply device of the present invention, each hydraulic pump device includes a variable speed electric motor and a pump unit driven by the electric motor, and the electric motor of each hydraulic pump device preferably has a rated performance such as power consumption and mechanical output. Are substantially equal to each other, and the pump unit is preferably a hydraulic pump device that is rated for a single specification and has a rated performance such as theoretical displacement capacity that is substantially equal to each other. In this way, by configuring the hydraulic supply device according to the present invention using the hydraulic pump device standardized to a single specification having equivalent performance, the manufacturer of the hydraulic supply device is a target to incorporate the hydraulic supply device. The required number of hydraulic pump devices of the same standard are selected according to the load capacity required for the base machine, for example, an injection molding machine, and these selected number of hydraulic pump devices are connected in parallel to a common hydraulic oil passage Accordingly, it is possible to provide a hydraulic pressure supply device that meets the requirements on the mother machine side. Of course, even in the case of the hydraulic supply device already installed in the mother machine, if the load capacity increases due to a change in the mold, etc., the necessary number of hydraulic pumps to cope with the increased load capacity In this case, the responsiveness of the entire hydraulic pressure supply device is maintained at the same level as the high responsiveness of the individual hydraulic pump devices.

  The hydraulic pressure supply device according to the present invention is not restricted by the type of hydraulic actuator device connected to the load side. These hydraulic actuator devices include various operating devices that convert hydraulic energy into mechanical energy, such as a hydraulic cylinder (cylinder / piston device), a hydraulic rotary motor (oil motor), or a hydraulic swing motor.

  The hydraulic fluid that can be used in the hydraulic pressure supply device according to the present invention may be a substantially incompressible lubricating fluid, and uses the hydraulic fluid rich in lubricity used in many industrial machines today. It is preferable to do. In general, it is preferable to use a hydraulic oil that has an appropriate viscosity, has a viscosity that hardly changes even when the temperature changes, maintains fluidity even at a low temperature, and does not easily change even when used at a high temperature. . In addition, it is desirable to select hydraulic fluids that are excellent in lubricity, wear resistance, oxidation resistance stability and shear stability, taking into consideration the operating conditions of the hydraulic actuator device on the mother machine side, and furthermore, it does not corrode metals. This is also an important characteristic. As such a hydraulic oil, generally, a petroleum hydraulic oil can be used, and in some cases, a synthetic hydraulic oil such as a phosphate ester or a silicate ester, or a water-in-oil emulsification system or water. -It is also possible to use a flame-retardant hydraulic fluid such as glycol.

  The control means in the hydraulic pressure supply device according to the present invention is characterized in that the pump units belonging to two or more hydraulic pump devices selected in advance according to the load capacity of the hydraulic actuator device connected to the load side have the same operating characteristics. It is comprised by the main controller which controls the rotation speed of the electric motor of each hydraulic pump apparatus synchronizing mutually. When the electric motor of each hydraulic pump device is constituted by the above-described commercially available servo motor product, the main controller controls the servo control unit of each hydraulic pump device under control. The speed feedback of the individual servo motors is provided to the individual servo control units from the rotational speed detector (encoder) attached to each servo motor, so that this is due to the individual servo control units included in the control loop by the main controller. Minor loop control. On the other hand, for example, the pressure of the hydraulic oil that drives the hydraulic actuator on the load side is the same as the hydraulic oil pressure in the hydraulic oil passage that communicates with the pump unit discharge port of each hydraulic pump device in common. The pressure detection signal is supplied to the main controller as a feedback signal. In this way, the machine output torque of the electric motors (servo motors) of all the hydraulic pump devices is servo-controlled in common through all the servo control units belonging to the control of the overall control by the main controller. Therefore, according to the present invention, only one pressure detector for pressure feedback control of each hydraulic pump device (thrust or torque servo control for the hydraulic actuator on the load side) is provided in the hydraulic fluid passage common to all the hydraulic pump devices. Would be enough.

  According to a preferred embodiment of the present invention, the hydraulic pressure supply device operates as a safety measure for preventing damage to the motors of all hydraulic pump devices belonging to the control means and the servo control unit attached thereto. A pressure detector that detects the pressure of the oil, and a drive stop unit that stops driving of all the hydraulic pump devices associated with the hydraulic oil passage when a detection signal from the pressure detector indicates an abnormal pressure value. In addition. As the pressure detector, the above-described pressure detector for pressure feedback control can be used, and the drive stop means can be realized as a function of a main controller constituting the control means. The hydraulic pressure in the hydraulic fluid passage is constantly monitored by the main controller based on the detection signal from the pressure detector. For example, when a pressure fluctuation that is more rapid than a preset pressure change rate is detected, the control means controls The power supply to the motors of all the hydraulic pump devices belonging to the lower side is cut off, and the drive of the hydraulic pump device is stopped.

  In a hydraulic supply device according to another preferred embodiment of the present invention, all the hydraulic pump devices under the control of the control means are controlled simultaneously and simultaneously with a common pressure feedback control, and the pump rotation speed is controlled. The apparatus starts the discharge operation in synchronization with each other. Therefore, the hydraulic oil discharged from one hydraulic pump device does not flow into the pump unit of another hydraulic pump device as it is, and the pump unit operates as a pump and operates as a hydraulic motor. There is no reverse rotation. As a result, it is possible to effectively prevent damage to the electric motor and the control equipment attached thereto, and when an abnormal pressure occurs in the hydraulic oil passage, the drive of all the hydraulic pump devices is immediately stopped. Even if an unexpected situation occurs, it is possible to enjoy the advantage that the electric motor and the control device are hardly damaged or malfunctioned. Needless to say, the cause of the abnormality is removed after the stop, and then the system is restored by restarting.

  As a pressure detector for safety measures and / or pressure feedback, various semiconductor pressure sensors are used as long as they generate a detection signal of an electric quantity linearly following the pressure of the hydraulic oil in the hydraulic oil passage. be able to. Since the hydraulic oil passage is in direct communication with the discharge port of the pump unit of each hydraulic pump device so as to allow the hydraulic oil to pass without obstruction in both the discharge direction and the suction direction. Presents a pressure value common to the pump device. Therefore, the pressure detector may be arranged at any position in the hydraulic oil passage, but generally it is preferably arranged at a position near the main controller so that the wiring of the detection signal line to the main controller does not become long.

  The drive stop means stops the drive of all hydraulic pump devices when the signal from the pressure detector indicates an abnormal situation. This is one function of the main controller constituting the control means as described above, for example. Can be realized. For example, if the controller simply sets an upper limit or lower limit for the pressure value in the hydraulic fluid passage detected by the pressure detector, the signal value from the pressure detector exceeds the upper limit or the lower limit. When the value falls below the value, the controller's judgment function recognizes the occurrence of an abnormal situation, and based on that, the emergency command signal issued from the controller cuts off the power supply to the motors of all controlled hydraulic pump devices, and the alarm is issued. At the same time, the driving of all the hydraulic pump devices is stopped. Of course, the drive stop means can be configured as an individual control system independent of the control means.

  According to another preferred embodiment of the present invention, the hydraulic pressure supply device is provided with a hydraulic safety device as a second safety measure for preventing damage to the motors and attached servo control units of all hydraulic pump devices belonging to the control means. A rotation speed detector that individually detects the rotation speed of the motor of the pump device, and a detection signal that indicates a rotation abnormality of the motor in any one of the hydraulic pump devices is output from the rotation speed detector. Drive stop means for stopping the drive of the hydraulic pump device is further provided.

  When the electric motor of each hydraulic pump device is constituted by a commercially available servo motor product, the rotation speed of each servo motor is measured by a rotation speed detector such as an attached encoder and can be constantly monitored by a servo control unit. In this case, for example, if the pressure in the hydraulic fluid passage suddenly increases due to an abnormality in the hydraulic actuator on the load side, the electric motor may be stopped due to the sudden increase in load. As a result, the pump unit connected to the stopped electric motor behaves as a hydraulic motor by the pressure increase in the hydraulic oil passage, and reverses the electric motor connected thereto. At this time, the electric motor functions as a generator to generate regenerative power, but the servo control unit is damaged by this regenerative power, so the servo control unit detects the occurrence of the state and generates an alarm signal. Usually it is equipped with a function. Therefore, this alarm signal is taken into the main controller, and when the main controller detects the alarm signal, the control of all the servo control units is cut off and the entire system can be temporarily stopped. This is an example of a second safety measure, and corresponds to an example in which the alarm function of the servo control unit and the shut-off function of the main controller for each servo control unit are used as drive stop means.

  An independent detector that individually detects the number of rotations of the motor of each hydraulic pump device may be separately prepared as the number of rotations detector, but when the rotary encoder that detects the number of rotations is built in the motor. It is preferable to utilize it. For example, when an inverter motor, a stepping motor, a servo motor, or the like is used as an electric motor, many commercially available products of these motors are equipped with an encoder that detects the rotational speed of the motor rotation shaft.

  The drive stop means may be constituted by a controller independent of the servo control unit and the main controller. The drive stop means disconnects all the hydraulic pump apparatus motors from the power source and stops driving the hydraulic pump apparatus when the detection signal output from the rotation speed detection means reaches a signal value that means abnormal rotation of the electric motor. . For example, by giving a simple comparison function to the servo control unit or the independent controller, the motor rotation abnormality can be detected by comparing the detection signal from the rotation speed detector with a preset upper limit value or lower limit value. The occurrence of an abnormality can be monitored, and when an abnormality occurs, the motors of all the hydraulic pump devices can be disconnected from the power source by the main controller or the independent controller, and the driving of the hydraulic pump devices can be stopped.

  The present invention also provides a method for controlling the driving of a plurality of hydraulic actuator devices using the hydraulic supply device as described above. That is, each comprising a variable speed electric motor and a pump unit driven by the electric motor, and a plurality of hydraulic pump devices having rated performances substantially equal to each other; communicated directly to the discharge port of each pump unit without using a valve, Each pump unit combines the flow of hydraulic oil discharged from each pump unit and leads it to the hydraulic actuator device on the load side, or diverts the flow of hydraulic oil returned from the load side actuator device in the opposite direction. A hydraulic fluid supply device including a hydraulic fluid passage for feeding into the hydraulic fluid; and a control means for controlling the number of revolutions of the electric motor of each hydraulic pump device. When the operations of the plurality of hydraulic actuator devices are selectively controlled, according to the control method of the present invention, the hydraulic actuator connected to the load side Are synchronized to control each other by chromatography data system speed said control means of each motor belonging to the hydraulic pump unit of the preselected 2 group or more number according to the load capacity of the.

  In a preferred embodiment of the control method according to the present invention, a first hydraulic fluid passage and a second hydraulic fluid passage connected to different hydraulic actuator devices are prepared as the hydraulic fluid passage, and these hydraulic fluids are prepared. The discharge port of the pump unit belonging to at least two or more of the hydraulic pump devices respectively to either one or both of the passages can be selectively communicated by the switching valve device, and according to the selection by the switching valve device, The number of revolutions of each electric motor belonging to the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator device connected to the first and / or second hydraulic fluid passage is controlled by the control means.

  In another preferred embodiment of the control method according to the present invention, at least a first hydraulic actuator device and a second hydraulic actuator device are prepared as the hydraulic actuator device, and one or both of these hydraulic actuator devices are prepared. Can be selectively connected to the working fluid passage by the on-off valve device, and according to the selection by the on-off valve device, the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator device connected to the hydraulic oil passage The number of rotations of each electric motor to which it belongs is controlled by the control means.

1 is a hydraulic circuit diagram illustrating a configuration of a hydraulic pressure supply device according to an embodiment of the present invention and an injection molding machine that is driven and controlled by the hydraulic pressure supply device. FIG. 2 is a hydraulic circuit diagram showing a circuit configuration of only a hydraulic pressure supply device part shown in FIG. 1. It is a block circuit diagram which shows the structure of the servo control system with respect to the electric motor of each hydraulic pump apparatus. It is a block circuit diagram at the time of incorporating the safety measure with respect to abnormal rotation of an electric motor in a servo control system. FIG. 3 is a hydraulic circuit diagram showing a configuration of a hydraulic pressure supply device when a plurality of hydraulic pump devices are selectively connected to a hydraulic oil passage. FIG. 3 is a hydraulic circuit diagram showing a configuration of a hydraulic pressure supply device and an injection molding machine when a plurality of hydraulic actuator devices are selectively connected to a hydraulic oil passage. It is a hydraulic circuit diagram which shows the structural concept of the hydraulic pressure supply apparatus by a prior art. It is a hydraulic circuit diagram which shows the structure of the hydraulic supply system of the injection molding machine using the some hydraulic pump apparatus by a prior art.

  In FIG. 1, the injection molding machine 20 includes a plurality of hydraulic actuators such as a variable speed hydraulic motor 23 for rotating the measuring screw 24, an injection cylinder 27, a shift cylinder 28, a mold clamping cylinder 35, and an ejector cylinder 38, for example. ing. In this embodiment, the hydraulic pressure supply device for the plurality of hydraulic actuators is composed of five hydraulic pump devices 10 having the same rated performance as each other as shown in FIG. Each of the hydraulic pump devices 10 includes a variable speed electric motor 11 and a pump unit 12 that is rotationally driven by the electric motor 11. The discharge port 13 of the pump unit 12 in each hydraulic pump device 10 is connected to one common hydraulic oil passage 21. The hydraulic actuators of the load side injection molding machine 20 are connected to the hydraulic oil passages via direction switching valves 22, 29, 32, 36, and 39, respectively. Here, the hydraulic oil passage 21 is in direct communication with the discharge port 13 of each pump unit 12 so as to allow the passage of the hydraulic oil in both the discharge direction and the suction direction without hindrance. Therefore, the flow of the hydraulic oil discharged from the individual pump units 12 is merged in the hydraulic oil passage 21 and then guided to the load-side hydraulic actuator device, or returned from the load-side hydraulic actuator device in the opposite direction. The flow of the hydraulic oil is divided in the hydraulic oil passage 21 and then guided to each pump unit 12.

  The pump units 12 of the five hydraulic pump devices 10 have the same rated performance. For example, the theoretical displacement capacities of the pump units 12 are the same. Similarly, the motors 11 of the five hydraulic pump devices 10 have the same rated performance. For example, the power consumption and the rated value of the machine output of each motor 11 are the same. In the present embodiment, each pump unit 12 comprises an axial piston pump having a swash plate having a predetermined constant tilt angle, and each motor 11 that rotationally drives this pump unit is a rotational speed detector (rotary). Encoder) It consists of a variable speed servo motor with built-in E. In the five hydraulic pump devices 10, each servo motor 11 is provided with a servo control unit 14 as shown in FIG. 3, for example, and the detection signal Vf from the built-in rotation speed detector E is servo controlled as a rotation speed feedback signal. Is given to unit 14. A command signal Sc is given to each servo control unit 14 of the five hydraulic pump devices 10 from a common main controller 15. The main controller 15 comprehensively controls each servo control unit 14 of each hydraulic pump device 10, and therefore the rotation speed of each servo motor 11 in the five hydraulic pump devices is controlled by the servo control unit 14 attached to each servo motor 11. The servo control is performed in synchronization with each other so as to follow the same command signal Sc given from one common main controller 15. In the hydraulic oil passage 21 that communicates in common with the discharge port 13 of the pump unit 12 of each hydraulic pump device 10, one pressure detector 40 that is common to all the hydraulic pump devices 10 is provided, and is operated by this pressure detector 40. The pressure of the hydraulic oil in the oil passage 21 is detected. A detection signal output from the pressure detector 40 is provided as a feedback signal Pf to the main controller 15, whereby all hydraulic pressures are transmitted via all servo control units 14 belonging to the control of the main controller 15. The machine output torque of the servo motor 11 of the pump device 10 is servo-controlled in common.

  For example, when the metering hydraulic motor 23 of the injection molding machine 20 is controlled to rotate in the forward direction according to a pre-programmed speed change pattern, the direction switching valve 22 is in the left switching position shown in FIG. A command signal Sc that changes in accordance with the speed change pattern is supplied from the main controller 15 to each servo control unit 14 under its control, and the servo motors 11 of the hydraulic pump devices 10 are started in a synchronized state. As a result, the five hydraulic pump devices 10 constituted by the servo motor 11 and the pump unit 12 having equivalent performances start discharging hydraulic oil substantially simultaneously and maintain the synchronized state while maintaining the speed. The discharge flow rate is changed corresponding to the change pattern. The flow of the hydraulic oil discharged from the five hydraulic pump devices 10 merges in the common hydraulic oil passage 21 from each discharge port 13, passes through the direction switching valve 22 from this hydraulic oil passage 21, and reaches the hydraulic motor 23. Supplied. As a result, the rotation speed of the hydraulic motor 23 is controlled according to the speed change pattern. When the metering hydraulic motor 23 is rotationally controlled in the reverse direction, the direction switching valve 22 is switched to the switching position on the right side shown in FIG. 1, and a command signal Sc corresponding to a predetermined speed change pattern for reverse rotation is used. Similar rotation speed control is executed. In any case, the operation of each hydraulic pump device 10 is servo-controlled in a synchronized manner from the start to the stop, and therefore a check valve for preventing the reverse flow of hydraulic oil into the discharge port 13 of each pump unit 12. Is unnecessary. As shown in FIGS. 1 and 2, the hydraulic oil passage 21 and the discharge port 13 of each pump unit 12 are in direct communication so as to allow the passage of bidirectional flow without hindrance. Since there is no intervention, the responsiveness regarding the change in the discharge flow rate of each hydraulic pump device 10 is not lowered.

  In addition, the pump unit 12 of each hydraulic pump device 10 can also be configured by a bidirectional rotary pump unit, whereby the hydraulic oil is released from the hydraulic actuator device side by reverse rotation control of the servo motor 11. Can fulfill. Also in this case, by operating the five hydraulic pump devices 10 in parallel, the pressure release operation can be performed at a large flow rate, and the cycle time of the injection molding machine can be shortened.

  On the injection molding machine 20 side, the in-line type measuring screw 24 is rotated by the rotation of the hydraulic motor 23 driven as described above, and the rotation of the screw 24 causes the hopper 26 to enter the heating barrel 25 having a heater (not shown). Supplies plastic raw materials (beads). In the barrel 25, the supplied raw material beads are plasticized by heating, and are fed to the front part in the barrel while being kneaded by the continuous rotation of the screw 24. At this time, the screw 24 is retracted by the pressure generated in the plasticizing resin filled in the front part of the barrel, and when the backward movement of the screw 24 reaches a predetermined position, a position detector (not shown) such as a limit switch is operated. The rotation of the screw 24 by the hydraulic motor 23 is stopped, whereby the amount of resin necessary for molding is measured. In this case, the pressure generated in the plasticized resin filled in the front part of the barrel can be arbitrarily adjusted by applying hydraulic pressure (screw back pressure) to the injection cylinder 27 so that the screw 24 does not move backward without resistance. This switches the direction switching valve 29 to the switching position shown on the right side in FIG. 1, and controls the pressure of the hydraulic oil supplied from the hydraulic pump device 10 based on the feedback signal Pf from the pressure detector 40. This is achieved by controlling so as to follow the command signal Sc. During this time, the mold clamping cylinder 35 is actuated by the switching operation of the direction switching valve 36, whereby the movable mold frame 33 approaches the fixed mold frame 34, and the resin pressure injected into the cavity in the mold 30 is increased. The mold is closed with sufficient clamping force. Thereafter, the barrel 25 is advanced toward the mold 30 by the shift cylinder 28, and the tip nozzle of the barrel 25 is fitted into the injection port 31 of the mold. In this state, the injection cylinder 27 is operated, and the resin filled in the front part in the barrel 25 is injected into the cavity in the mold 30. When the inside of the cavity is filled with resin, the pressure of the injection cylinder 27 is switched from the filling pressure to the holding pressure, and proper molding conditions in the cavity are maintained. After a predetermined time elapses, the mold clamping cylinder 35 is operated in the reverse direction to open the mold, and then the molded product is taken out from the mold by the ejector pin 37 in accordance with the operation of the ejector cylinder 38.

  The operation of the injection molding machine 20 described above is executed by controlling the operation of each hydraulic pump device and each direction switching valve by a program control operation by the main controller 15. The main controller 15 controls the operation of each hydraulic pump device 10 and each directional switching valve 22, 29, 32, 36, 39 according to a preprogrammed operation sequence. For example, the connection flow path to the hydraulic oil passage 21 is switched by the direction switching valve 29 for the injection cylinder 27 and the direction switching valve 32 for the shift cylinder 28, respectively. As a result, each cylinder selectively moves forward, stops, or moves backward, and the moving speed and torque during these operations are synchronized with each other in rotational speed control (flow rate control) and common pressure detection in each hydraulic pump device 10. Control is performed so as to follow the command signal Sc by feedback control (back pressure control) of the discharge pressure using the container 40.

  Similarly, on the mold 30 side, the clamping cylinder 35 is selectively advanced by the direction switching valve 36 and the ejector cylinder 38 is selectively advanced by switching the connection flow path to the hydraulic oil passage 21 by the direction switching valve 39, respectively. The moving speed and torque during these operations are commanded by the rotational speed control synchronized with each other in each hydraulic pump device 10 and the discharge pressure feedback control using the common pressure detector 40. It is controlled to follow the signal.

  The hydraulic motor 23 and the cylinders 27, 28, 35, and 38 each require a specific operating capacity. Accordingly, the main controller 15 synchronizes with the switching operation of the directional control valves 22, 29, 32, 36, and 39 in accordance with a preset program, and sends a corresponding rotational speed command to the servo unit 14 of each hydraulic pump device 10. Give a signal. As a result, hydraulic oil can be supplied from the hydraulic supply device at a required flow rate / pressure according to the operation sequence of the injection molding machine.

  The main controller 15 detects the pressure of the hydraulic oil in the hydraulic oil passage 21 as a safety measure for preventing damage to the servo motors 11 and the attached servo control units 14 of all the hydraulic pump devices 10 belonging to the control. When the detection signal from the pressure detector 40 indicates an abnormal pressure value, a drive stop function is provided to stop driving all the hydraulic pump devices 10 associated with the hydraulic oil passage 21. As shown in FIG. 3, on the one hand, the hydraulic oil pressure in the hydraulic oil passage 21 is constantly monitored by the main controller based on the detection signal Pf from the pressure detector 40, and on the other hand, the hydraulic oil detected by the pressure detector 40. An upper limit value and a lower limit value are set in the main controller for the pressure value in the passage 21. When the signal value from the pressure detector 40 exceeds the upper limit value or falls below the lower limit value, the occurrence of an abnormal situation is recognized by the determination function of the main controller. Based on this, an emergency stop command signal is given from the main controller 15 to the servo control units 14 of all the hydraulic pump devices 10 under control. As a result, the power supply to the servo motors 11 of all the hydraulic pump devices 10 is cut off, the alarm signal AL is sent from the servo control unit 14 to the main controller, and the driving of all the hydraulic pump devices 10 is stopped. Note that, for example, the occurrence of an abnormal state may be recognized by the main controller 15 when a pressure fluctuation that is more rapid than a preset pressure change rate is detected.

  In the embodiment shown in FIG. 4, a safety measure function against abnormal rotation of the servo motor 11 is incorporated in the main controller. That is, the rotation speed of the servo motor 11 in each hydraulic pump device 10 is measured by a rotation speed detector (rotary encoder) E attached to each servo motor, and is provided to the servo control unit 14 as a feedback signal Vf. Each servo control unit 14 constantly monitors the value of the feedback signal Vf. When the value of the feedback signal Vf exceeds a preset threshold value, an alarm signal AL is sent from the servo control unit 14 to the main controller 15. The main controller 15 incorporates a drive stop function for stopping the drive of all the hydraulic pump devices 10 when an alarm signal is sent from any one of the servo control units 14 of the hydraulic pump devices 10. . Instead of monitoring based on the upper and lower limits of the motor rotation speed, a similar drive stop function can be activated by simply monitoring the generation of regenerative power from the servo motor 11. For example, the servo motor 11 of each hydraulic pump device 10 may be brought to an emergency stop due to a sudden increase in load when the pressure in the hydraulic fluid passage 21 suddenly increases due to a failure of a load side hydraulic actuator device or the like. In this case, the pump unit 12 connected to the stopped servo motor 11 temporarily behaves as a hydraulic motor due to the pressure increase in the hydraulic oil passage 21, and the servo motor 11 connected thereto is rotated in the reverse direction. There is. Thus, when the servo motor 11 functions as a generator, regenerative power generated from the servo motor 11 flows into the servo control unit 14. A general servo control unit incorporates a function for detecting the generation of the regenerative power and generating an alarm signal AL so that the regenerative power does not cause damage. Therefore, the alarm signal AL is taken into the main controller 15, and when the main controller 15 detects the alarm signal AL, the control operation of all the servo control units 14 under control is cut off to temporarily stop the entire system. it can.

  In the hydraulic pressure supply device according to the present invention, as shown in FIGS. 1 and 2, a circuit in which all hydraulic pump devices 10 are always in communication with a common hydraulic fluid passage 21 with respect to a bidirectional flow. Although a system can be adopted, instead of this, a circuit system in which each hydraulic pump device 10 is selectively communicated to a separate hydraulic oil passage for each flow direction can also be adopted. That is, in the embodiment shown in FIG. 5, a first hydraulic oil passage 21a and a second hydraulic oil passage 21b connected to different hydraulic actuator devices are prepared as hydraulic oil passages. The discharge ports 13 of the pump units 12 belonging to at least two or more hydraulic pump devices 10 can be selectively communicated with each other or both by the switching valve device 50. In this case, the main controller 15 has a number of hydraulic pressures corresponding to the load capacity of the hydraulic actuator device connected to the first hydraulic fluid passage 21a and / or the second hydraulic fluid passage 21b according to the selection by the switching valve device 50. The rotational speed of each servo motor 11 belonging to the pump device 10 is controlled.

  In yet another embodiment shown in FIG. 6, a plurality of hydraulic actuator devices are selectively connected to the hydraulic fluid passage. That is, in the plurality of hydraulic actuator devices of the injection molding machine 20, the hydraulic motor 23, the injection cylinder 27, and the shift cylinder 28 on the injection machine side are connected to the hydraulic oil passage 61a as a first group, and the mold clamping cylinder 35 on the mold side. The ejector cylinder 38 is connected to the hydraulic oil passage 61b as a second group. An on-off valve device 62 is interposed between the hydraulic oil passages 61a and 61b, and these hydraulic oil passages 61a and 61b are selectively connected or disconnected.

  When the on-off valve device 62 is in the communication position as shown in FIG. 6, the first group of hydraulic actuator devices connected to the hydraulic fluid passage 61a and the second group of hydraulic actuators connected to the hydraulic fluid passage 61b The apparatus receives supply of hydraulic oil from a total of five hydraulic pump apparatuses 10a and 10b. On the other hand, when the on-off valve device 62 is switched to the shut-off position, each hydraulic actuator device of the first group connected to the hydraulic oil passage 61a receives supply of hydraulic oil from the three hydraulic pump devices 10a. Independently, each hydraulic actuator device of the second group connected to the hydraulic oil passage 61b is supplied with hydraulic oil from the two hydraulic pump devices 10b. In this way, either one or both of the hydraulic actuator devices of the first group and the hydraulic actuator devices of the second group are selectively connected to the working fluid passage by the on-off valve device 62.

  The main controller 15 controls the rotation speed of each servo motor belonging to the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator devices connected to the hydraulic oil passages 61a and / or 61b according to the selection by the on-off valve device 62. To do.

  As a result, the hydraulic actuator devices for each group can be controlled independently of each other, or both can be integratedly controlled. As a result, it is possible to select individual operation and simultaneous operation for each group, shortening the operation cycle time of the injection molding machine, and saving power by stopping some servo motors depending on the situation. is there.

  As described above, in the present invention, a plurality of hydraulic pump devices are selectively operated in parallel by the synchronous servo control system on the hydraulic pressure supply device side to join the discharge hydraulic fluid, and the hydraulic fluid having a flow rate suitable for the load capacity is used. Since multiple hydraulic actuator devices are driven, even if the accuracy of the rotational speed detector such as a rotary encoder is low compared to the conventional method of superimposing mechanical power using easily damaged devices such as ball screws and gears Stable control can be performed and a closed loop can be constructed using a single pressure detector common to all hydraulic pumps as a feedback system for pressure control. Control can be performed.

  Furthermore, according to the present invention, it is possible to prevent the occurrence of a failure that leads to the damage of the system by monitoring the rotation of the electric motors of the individual hydraulic pump devices. It is also possible to provide a high hydraulic pressure supply device.

Claims (8)

A plurality of hydraulic pump devices each including a variable speed electric motor and a pump unit driven by the electric motor; allowing the hydraulic oil to pass through the discharge port of each pump unit in both the discharge direction and the suction direction without hindrance In this way, the flow of hydraulic oil discharged from the individual pump units is merged and guided to the hydraulic actuator device on the load side, or the hydraulic fluid returned from the actuator device on the load side in the reverse direction. A hydraulic oil passage for diverting the flow to each pump unit; and for controlling the rotation speeds of the motors of each hydraulic pump device in synchronism with each other so that each pump unit operates with equivalent operating characteristics. With control means ,
Each variable speed electric motor is constituted by a servo motor combined with a servo control unit for controlling the rotational speed and a rotational speed detector,
Each servo control unit of each hydraulic pump device is comprehensively controlled by the control means,
In each hydraulic pump device, a feedback signal corresponding to the rotation speed of the servo motor detected by the rotation speed detector is given to the servo control unit,
Thereby, the number of rotations of each servo motor is servo-controlled so as to follow the control command given from the control means to each servo control unit,
The hydraulic oil pressure in the hydraulic oil passage communicating with the discharge port of the pump unit of each hydraulic pump device in common is detected by a common pressure detector,
The detection signal by this pressure detector is given as a feedback signal to the control means,
Accordingly, the mechanical output torque of the servo motors of all the hydraulic pump devices is servo-controlled in common through all the servo control units belonging to the overall control of the control means . Pressure detector detects the pressure of the working oil of the hydraulic fluid passage; and driving of all the hydraulic pump unit associated with the hydraulic fluid passage when the detection signal from the pressure detector indicates an abnormal pressure value The hydraulic pressure supply device according to claim 1, further comprising drive stop means for stopping the motor.   A rotational speed detector for individually detecting the rotational speed of the electric motor of each hydraulic pump device; and a detection signal indicating an abnormal rotation of the electric motor in at least one of the hydraulic pump devices is output from the rotational speed detector. 2. The hydraulic pressure supply device according to claim 1, further comprising drive stop means for stopping the drive of all the hydraulic pump devices. An injection molding machine comprising the hydraulic pressure supply device according to any one of claims 1 to 3. A plurality of hydraulic pump devices each having a variable speed electric motor and a pump unit driven by the electric motor, the rated performances of which are almost equal to each other; directly connected to the discharge ports of the respective pump units without using valves, The flow of hydraulic oil discharged from the pump unit is merged and guided to the hydraulic actuator device on the load side, or the flow of hydraulic oil returned from the load side actuator device is diverted in the opposite direction and sent to each pump unit. a control means for controlling the rotational speed of the electric motor and the hydraulic pump unit; hydraulic oil passage for
Each variable speed electric motor uses a hydraulic pressure supply device constituted by a servo motor combined with a servo control unit for controlling the rotational speed and a rotational speed detector ,
When selectively controlling the operation of a plurality of hydraulic actuator devices on the load side via the hydraulic oil passage by the hydraulic pressure supply device,
The rotational speed of each electric motor belonging to two or more hydraulic pump devices selected in advance according to the load capacity of the hydraulic actuator device connected to the load side is controlled in synchronization with each other by the control means ,
The servo control unit of each hydraulic pump device is controlled by the control means,
A feedback signal corresponding to the rotation speed of the servo motor detected by the rotation speed detector is given to each servo pump unit to the servo control unit.
Each servo control unit servo-controls the rotation speed of each servo motor so as to follow the control command given from the control means,
The hydraulic oil pressure in the hydraulic oil passage communicating in common with the discharge port of the pump unit of each hydraulic pump device is detected by one common pressure detector,
The detection signal by this pressure detector is given as a feedback signal to the control means,
A drive control method for a hydraulic actuator device, wherein the mechanical output torque of servo motors of all hydraulic pump devices is commonly controlled via all servo control units belonging to the control of the overall control by the control means .   First hydraulic fluid passages and second hydraulic fluid passages connected to different hydraulic actuator devices as the hydraulic fluid passages are prepared, and at least two of each of the hydraulic fluid passages are provided. The discharge port of the pump unit belonging to the above hydraulic pump device can be selectively communicated by the switching valve device, and is connected to the first and / or second hydraulic oil passages according to the selection by the switching valve device. 6. The method according to claim 5, wherein the number of rotations of each electric motor belonging to the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator device is controlled by the control means.   At least a first hydraulic actuator device and a second hydraulic actuator device are prepared as the hydraulic actuator device, and either or both of these hydraulic actuator devices can be selectively connected to the working fluid passage by an on-off valve device. The number of rotations of each electric motor belonging to the number of hydraulic pump devices corresponding to the load capacity of the hydraulic actuator device connected to the hydraulic oil passage is controlled by the control means according to the selection by the on-off valve device. The method according to claim 5. An injection molding machine drive control method using the injection molding machine according to claim 4,
When selectively controlling the operation of a plurality of hydraulic actuator devices on the load side via the hydraulic oil passage by the hydraulic pressure supply device,
The rotational speed of each electric motor belonging to two or more hydraulic pump devices selected in advance according to the load capacity of the hydraulic actuator device connected to the load side is controlled in synchronization with each other by the control means,
The servo control unit of each hydraulic pump device is controlled by the control means,
A feedback signal corresponding to the rotation speed of the servo motor detected by the rotation speed detector is given to each servo pump unit to the servo control unit.
Each servo control unit servo-controls the rotation speed of each servo motor so as to follow the control command given from the control means,
The hydraulic oil pressure in the hydraulic oil passage communicating in common with the discharge port of the pump unit of each hydraulic pump device is detected by one common pressure detector,
The detection signal by this pressure detector is given as a feedback signal to the control means,
A drive control method for an injection molding machine, characterized in that the machine output torque of servo motors of all hydraulic pump devices is commonly controlled via all servo control units belonging to the control of the overall control by the control means.

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