JP2005169807A - Method for optimally controlling inverter of hydraulic molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method which enable the rational control of the inverter of a hyudraulic molding machine in an energy-saving manner without causing a state that necessary oil pressure or an oil flow rate can not be outputted, and a device therefor. <P>SOLUTION: The hydraulic molding machine is equipped with a hydraulic pump, an electromotor for driving the hydralic pump, the inverter for changing the frequency of the voltage applied to the electromotor and a control device for adjusting and controlling the voltage frequency of the inverter. The control method of the hydraualic molding machine has a master process for determining the respective preliminarily determined master operation times of the respective unit processes of a molding process and an adjusting process for adjusting the frequency of the applied voltage of the inverter at every unit process to set the same and a process for controlling the inverter from set frequency. In the adjusting process, a final frequency set value is adjusted by comparing the master operation time and an operation time at the time of adjustment to change the frequency of the applied voltage of the inverter so that the operation time at the time of adjustment becomes substantially equal to the master operation time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molding machine control method and apparatus therefor, and more particularly, to a hydraulic molding machine inverter control method and apparatus therefor, and more particularly to an optimization method in inverter control of an existing hydraulic molding machine. And an apparatus for the same.

  In recent years, energy savings have attracted attention due to the occurrence of oil shocks. In addition, energy saving has been promoted in equipment and devices. Since then, various devices, equipment, systems and methods with energy-saving functions have been proposed and developed. On the other hand, there is a problem of energy saving of existing non-energy-saving devices and devices, and it is not always reasonable to replace such existing devices and devices with new energy-saving devices or devices. There are quite a few cases that are not possible. Therefore, energy saving of existing devices, devices, etc. that have not been energy saving has become an important theme.

  Conventionally, in a hydraulic molding machine, a hydraulic pump is driven by a constant rotation AC motor, and the molding machine is driven by the hydraulic pressure. In the operation of the hydraulic molding machine, various steps are provided as shown in FIG. Since the required hydraulic flow rate and pressure are different in these various steps, the power consumption also changes with time as shown in FIG. The capacity, i.e. flow rate and discharge pressure, of a hydraulic pump operating at a constant rotational speed is therefore selected to have the required maximum flow rate and maximum pressure, and the pump motor that drives the hydraulic pump is also typically the maximum flow rate and maximum pressure. It is selected so that it has the ability necessary to demonstrate. When such a hydraulic pump of a conventional hydraulic molding machine is operated at a constant rotational speed, the discharge flow rate is substantially the maximum flow rate. Thus, excess flow is generally returned from the relief valve to the oil tank in steps in various molding processes that do not require maximum flow. The flow rate returning to the oil tank is unused power, that is, power loss. In the conventional hydraulic molding machine, there is such a waste of energy (loss).

  In order to improve the energy loss when the above hydraulic pump is operated at a constant rotation, an inverter is placed in front of the AC motor for driving the hydraulic pump, and the rotation speed of the AC motor is increased or decreased as necessary. As a result, energy saving has been achieved. However, in such energy saving control, if the frequency of the inverter is lowered too much, the output of the hydraulic pump is lowered, and the necessary oil pressure and oil amount cannot be obtained. Therefore, a method has been adopted in which whether or not the output of the hydraulic pump is appropriate is determined by measuring the hydraulic pressure or the amount of oil from the pump. However, adding these measuring instruments to existing equipment is costly and technically difficult, and the molding is composed of a number of different processes as described above. Obtaining the optimum frequency of the inverter for many processes and performing the adjustment mainly depending on human judgment requires a great amount of man-hours in adjusting the frequency.

  The configuration of the conventional hydraulic molding machine described above is basically the same as that of the present invention (in other words, in the present invention, the control device according to the present invention is added), so that the later present invention Is described in the description of the preferred embodiment (see FIGS. 1 and 2), and is omitted here. Since the operation of the conventional hydraulic molding machine is the same as that of the present invention, portions related to the present invention will be described in the following part, and differences from the conventional one will also be described. Omitted.

As described above, in a conventional hydraulic molding machine, in particular, a hydraulic molding machine in which a hydraulic pump is driven by an existing AC electric motor having a constant rotation speed, an additional measuring device is installed in order to save energy. In addition, there have been difficult problems such as obtaining an appropriate frequency for each step of each process, and even if the appropriate frequency can be obtained by comparison, requiring a large number of man-hours.
The present invention has been made in view of the above-described circumstances, and in a control method for changing the frequency of the supply voltage of an inverter of a hydraulic molding machine, it is impossible to obtain a necessary hydraulic pressure and oil flow rate for a hydraulic pump motor using the inverter. It is an object of the present invention to provide a method capable of rationally saving energy without causing such a state and a control device for implementing the method.

  Another object of the present invention is that energy saving control by adjusting the frequency by the inverter of the hydraulic molding machine does not require a great amount of man-hours in order to obtain an appropriately adjusted frequency, and all the equipment is controlled by a control device such as a computer. It is an object of the present invention to provide a control method capable of automatically obtaining the frequency during operation of the apparatus and an apparatus for implementing the control method.

  According to a first aspect of the present invention, in order to achieve the above-described object, in the control method of a hydraulic molding machine, the hydraulic molding machine drives at least one hydraulic pump and the at least one hydraulic pump. At least one electric motor, at least one inverter connected to the at least one electric motor and changing a frequency of a voltage supplied thereto, and the at least one inverter controlled to be supplied from the inverter And a control device for adjusting the frequency of the voltage. The control method includes a master procedure for determining in advance each master operation time as a target of each unit process of the molding process, and an adjustment procedure for adjusting and setting the frequency of the supply voltage of the inverter for each unit process. And further comprising: a sub-procedure for adjusting the frequency of the supply voltage of the inverter by the control device in each unit process and measuring an operation time during adjustment of each unit process at each time; Regarding the unit process, the master operation time is compared with the adjustment operation time, and the adjustment is performed by changing the frequency of the supply voltage of the inverter to the limit frequency at which the adjustment operation time is substantially equal to the master operation time. A sub-procedure for determining a set frequency of a supply voltage of the inverter related to each unit process to the limit frequency, and the inverter related to each unit process Control method comprising; a set frequency of the supply voltage, the sub-steps of storing in said controller, be provided with a.

  By configuring in this way, it is possible to rationally save and control the hydraulic pump motor using the inverter without causing a state where the required hydraulic pressure or oil flow rate cannot be obtained. Further, when energy saving control is performed on existing equipment according to the present invention, it can be realized by measuring the operation time of the process without adding a measuring instrument, piping or wiring therefor. In energy-saving control by adjusting the frequency with an inverter, in order to obtain an appropriately adjusted frequency, a large number of man-hours are not required, and the frequency is automatically obtained during operation of the equipment by a control device such as a computer. I can do it.

According to a second aspect of the present invention, in the first aspect, the inverter is controlled by the control device so that the inverter supplies a voltage of the set frequency in the molding step after the adjustment procedure. The method further includes the step of:
According to this embodiment, since the operation of the hydraulic molding machine in an energy-saving state can be continuously performed following the energy-saving adjustment stage, an efficient molding process can be realized.

According to a third aspect of the present invention, in the first or second aspect of the present invention, in the master procedure, a voltage having a predetermined frequency is supplied from the at least one inverter to the at least one electric motor. In this case, the operation time of each unit process of the molding process performed by the hydraulic molding machine is measured to determine each master operation time of each unit process.
According to the present embodiment, the method for determining each master operation time is made more specific.

According to a fourth aspect of the present invention, in the third aspect, in the procedure for determining the master operating time, the frequency of the supply voltage of the inverter is set to a frequency at which the inverter does not adjust the frequency. .
With this configuration, since the frequency adjustment is generally performed in a decreasing direction, the target frequency to be set can be obtained more easily and faster.

  According to a fifth aspect of the present invention, in the adjustment procedure according to any one of the first to fourth aspects, the frequency of the supply voltage of the inverter is adjusted and set for each unit process. Each unit process is divided into an odd-numbered process group and an even-numbered process group. An adjustment process is performed for one group of processes, for example, an even-numbered process, and a set frequency for each even-numbered process is determined and stored in the control device. After that, the adjustment process is performed for the other group of processes, in the above example, the odd number process, and the set frequency for each odd number process is determined.

  According to this embodiment, if there is a change in frequency when moving from each single step to the next single step, there will be a delay in the response of the inverter, which causes the previous frequency factor to affect the operating time measurement. On the other hand, the adjustment process is divided into an even-numbered step adjustment process and an odd-numbered step adjustment process, and is carried out in two stages. (For example, 60 Hz), the influence of the response delay variation of the inverter is substantially eliminated.

  A hydraulic molding machine according to a sixth aspect of the present invention is characterized in that the control method according to any one of the first to fifth aspects is executable.

  With the hydraulic molding machine configured in this manner, the energy saving control can be rationally performed without causing a state in which a necessary hydraulic pressure or oil flow rate cannot be obtained using an inverter. Further, when energy saving control is performed on existing equipment according to the present invention, it can be realized by measuring the operation time of the process without adding a measuring instrument, piping or wiring therefor. In energy-saving control by adjusting the frequency with an inverter, in order to obtain an appropriately adjusted frequency, a large number of man-hours are not required, and the frequency is automatically obtained during operation of the equipment by a control device such as a computer. I can do it.

According to a seventh aspect of the present invention, there is provided a control apparatus for a hydraulic molding machine comprising a program capable of executing the control method according to any one of the first to fifth aspects.
With the hydraulic molding machine control device configured as described above, the energy saving control can be rationally performed without causing a state in which the necessary hydraulic pressure or oil flow rate cannot be obtained by using the inverter. Further, when energy saving control is performed on existing equipment according to the present invention, it can be realized by measuring the operation time of the process without adding a measuring instrument, piping or wiring therefor. In energy-saving control by adjusting the frequency with an inverter, in order to obtain an appropriately adjusted frequency, a large number of man-hours are not required, and the frequency is automatically obtained during operation of the equipment by a control device such as a computer. I can do it. Furthermore, the effect of variations in the response delay of the inverter when moving from each single step to the next single step may be substantially eliminated.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an apparatus and a method according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows a mechanical configuration of a first embodiment of a hydraulic molding machine according to the present invention, and FIG. 2 shows a first embodiment of the hydraulic molding machine according to the present invention. A control structure is shown roughly. Referring first to FIG. 1, in the present embodiment, a hydraulic molding machine 1 which is an injection molding machine is shown. The hydraulic molding machine 1 shown in FIG. 1 is modified by incorporating the control device 25 of the present invention into a conventional existing molding machine. The hydraulic molding machine 1 includes a molding die 3 that molds a product, an injection arrow 2 that is supplied with a molding material and injects the molding material into the molding die 3, a hydraulic device, and an electric device. The configuration example of the present embodiment is intended to facilitate the explanation of the present invention, and the detailed configuration includes portions that are different from the practical configuration, such as omitting unnecessary portions for the description. Recognize that there is.

  The hydraulic apparatus includes hydraulic pumps 5 and 6, an oil tank 4 that stores hydraulic oil, a hydraulic cylinder 7, a hydraulic cylinder 9, and a hydraulic motor 8. The hydraulic cylinder 7, the hydraulic cylinder 9, and the hydraulic motor 8 are supplied with high-pressure hydraulic oil from the hydraulic pump 5 or 6, and the injection arrow 2 is driven to inject the molding material, close the mold, etc. Perform molding work. The numbers of hydraulic motors, hydraulic pumps, and hydraulic cylinders in the present embodiment are examples for ease of explanation, and may be other than those shown in the drawings. In FIG. 1, the hydraulic apparatus further includes a throttle valve 11, a relief valve 12, etc., and devices such as a stop valve, a filter, and a sensor that are actually provided are omitted from the drawing for convenience of explanation. Some are.

  The electric device includes a pump motor 21 that drives the hydraulic pumps 5 and 6 and is an AC motor, an inverter 22, a sequencer 24, a power source 23, and a control device 25 according to the present invention. Referring to FIG. 2, a control configuration of the hydraulic molding machine 1 according to the present embodiment is illustrated schematically, and a power source 23 supplies power to the pump motor 21 via an inverter 22. The inverter 22 is controlled by the control device 25 to change the frequency of the voltage to the pump motor 21 and change the rotation speed of the pump motor 21. The pump motor 21 drives at least one of the two pumps 5 and 6 to send the hydraulic pressure to the hydraulic motor 8 and the hydraulic cylinders 7 and 9. As the rotational speed of the pump motor 21 changes, the supply flow rates of the pumps 5 and 6 can also change. A molding process is programmed in the sequencer 24, and a control signal is sent to various devices included in the molding machine 1, such as a flow controller, according to the process. The control device 25 practices control according to the present invention, such as controlling the frequency of the inverter 22.

  In the conventional hydraulic molding machine, the hydraulic pump driving AC motor 21 is operated at a constant rotation, so that the hydraulic pump 5 (and / or 6) supplies hydraulic oil to the hydraulic motor 8 and the cylinders 7 and 9 at a constant flow rate. The excess hydraulic oil escapes from the relief valve 12 and returns to the oil tank 4. A molding process using a conventional hydraulic molding machine is configured according to various procedures as shown in FIG. 6 or 7, but generally the required oil amount and oil pressure are different in each process. On the other hand, since the hydraulic pump 5 is selected so as to be able to exhibit the maximum flow rate and the maximum pressure, an excessive flow rate is inevitably generated in most processes. In each step, it can be said that the most efficient operation of the hydraulic pump 5 is that no surplus hydraulic oil is generated, that is, the hydraulic oil does not escape from the relief valve 12.

Next, a control method in the present embodiment will be described.
In the molding process using the hydraulic molding machine of the present invention, it is constituted by various procedures as shown in FIG. 6 (or 7). The inventor of the present invention has proposed a control device 25 that includes a program for efficiently obtaining the number of rotations of the hydraulic pumps 5 and 6 that do not generate an excessive flow rate for each step of each process. It is proposed that the control device 25 is operated in accordance with a program for controlling the hydraulic pump 5 so as to be set as follows.

  In the first embodiment of the present invention, referring to the control flow of FIG. 4, when the operation starts (S0), the master adjustment mode (S1) is first performed. In the master adjustment mode, in the initial state, the hydraulic pumps 5 and 6 are operated at a maximum flow rate (power (input voltage) frequency is operated at a maximum of 60 Hz, and therefore the pump motor 21 (for example, 1800 RPM), that is, the hydraulic pump 5 and 5 are operated. 6 is the maximum). In the master adjustment process, the hydraulic pumps 5 and 6 exhibit the maximum flow rate, and in the entire molding process, that is, in this embodiment, the standby step that is the final step from the product extrusion return step that is the first step of the molding process. Drive up to the step. At this time, in each step, the operation time of each step (the time from the start to the end of each step) and the total power consumption in each step are measured. The operation time of each step measured in the master adjustment process is set as a master measurement value.

  Next, in the present embodiment, as the adjustment step (mode) (S2), the even step adjustment step (S20) is performed, and the input voltage frequency of the even number step is reduced by, for example, 5 Hz and operated at 55 Hz (this In the example, the rotation speed of the pump motor 21 is about 1650 RPM, and the flow rate of the hydraulic pump 5 is about 91%) (first adjustment step). Specifically, in FIG. 6, in the second step, the high pressure mold closing step, the fourth step, the boosting step, the sixth step, the injection step, etc. Measure time and total power consumption. At this time, for example, if the operation time does not become long in the high pressure mold closing of the second step, it is considered that the surplus flow rate still exists in the flow rate of the hydraulic pump 5 and the surplus flow rate has escaped from the relief valve 12. It is done. Accordingly, since it is considered that the flow rate can be further reduced and the power can be reduced, the input voltage frequency is further reduced by 5 Hz in the next second adjustment step. On the contrary, if the operation time becomes long in the high pressure mold closing in the second step, there is no surplus flow rate in the flow rate of the hydraulic pump 5, and the surplus flow rate does not escape from the relief valve 13. Conceivable. Therefore, if the flow rate is further reduced, the operation time is considered to be further extended. Therefore, the input voltage frequency is not further reduced in the next third adjustment step, and the operation at 60 Hz is performed in the second step high voltage type closing. (In this case, the adjustment process is completed with respect to the high-pressure mold closing in the second step).

  Thus, in the first adjustment step of the even step adjustment step (S20), the operation time is measured by reducing the input voltage frequency of each even number step by a predetermined width (5 Hz in this embodiment). Compared with the master measurement value, the necessity of frequency adjustment is determined for each step in the same manner as the high-pressure mold closing in the second step. In the second adjustment process, with respect to even-numbered steps as well, in the present embodiment, 5 Hz is further added except for the step in which the adjustment is not required in the previous first adjustment process (the operation time has been extended). Reduce the frequency and operate at 50Hz, measure the operating time, and compare with the master measurement value. For the step where the operation time does not extend, it is determined that further adjustment is necessary, and the input voltage frequency is further adjusted in the next adjustment process. For the step where the operation time is extended, it is determined that no further adjustment is necessary and the frequency is adjusted. Finish the adjustment.

  Such adjustment is repeated until no adjustment is required for all even steps. When adjustment is no longer necessary, adjustment is completed for all even steps, and adjusted frequencies are obtained. Next, in the flow of FIG. 4, the process proceeds to the next odd-numbered step adjustment step (S30).

  In the odd step adjustment step (S30), the output voltage frequency of the inverter 22 of the odd numbered step is reduced by, for example, 5 Hz from the master measurement value and operated at 55 Hz. Specifically, in FIG. 6, in the first step of product extruding step, the third step of low pressure mold closing, the fifth step of nozzle advancement, etc., the operation is performed at a frequency lowered by 5 Hz. Again, the operating time and total power consumption are measured. At this time, as with the even step adjustment process described above, for each odd step, the step in which the measured operation time does not extend compared to the master measurement value is determined to require further adjustment, and further output is performed in the next adjustment process. Regarding the step of adjusting (decreasing) the voltage frequency and extending the operation time, it is determined that further adjustment is unnecessary and the adjustment is terminated. Then, adjustment (decrease the frequency) is performed until adjustment is unnecessary for all odd-numbered steps, and an adjusted (set) frequency is obtained.

  As described above, the even-numbered step adjusting process (S20) and the odd-numbered step adjusting process (S30) are sequentially performed, and the adjusting process ends when the set frequencies adjusted for all the steps are obtained. At this time, the set frequency of the supply voltage of the inverter for all steps of the molding process of the hydraulic molding machine 1 (that is, the operation time is also determined) is determined (S40). Each determined set frequency is stored in the control device 25 in a form corresponding to each step of the molding process (S50). Next, the operation proceeds to the normal operation mode (S3).

  In the normal operation mode (S3), at each step, the control device 25 controls the inverter 22 so as to set the adjusted frequency stored in the control device 25 obtained in the adjustment step. , 6 are operated at a flow rate based on the adjusted frequency. The adjusted frequency is generally lower than the master measurement value, and accordingly, the flow rate of the hydraulic pumps 5 and 6 is adjusted so as to decrease compared to the master measurement value, so that the power consumption is reduced. This can be seen from the power consumption at each step measured in the adjustment process, and the result is shown by a solid line in FIG. 6, and in FIG. 6 compared to the conventional case of FIG. 7 (or the dotted line of FIG. 6). It can be seen that the power consumption has been reduced.

  In the above embodiment, the adjustment process (S2) is divided into the even-numbered step adjustment process (S20) and the odd-numbered step adjustment process (S30). If the frequency is changed when moving to the step, there is a response delay of the inverter 22, which causes the previous frequency factor to affect the measurement of the operation time. In the adjustment process, by measuring every other step, the frequency adjustments are all adjusted from 60 Hz, so that the influence of the response delay variation of the inverter 22 is substantially eliminated.

Further, in the present embodiment, the odd-numbered step adjusting process is performed after the even-numbered step adjusting process, but this may be reversed. Furthermore, the adjustment process may not be divided into an even-numbered step adjustment process and an odd-numbered step adjustment process, and even in this case, all the advantages of the present invention are not lost.
Further, in the present embodiment, the frequency change width is performed every 5 Hz in the adjustment step. However, this change width may be larger or smaller.
In the above-described embodiment, the total electric energy is measured in order to embody the effect of the present invention, and may not be measured.

  The control program according to the first embodiment of the present invention shown in FIG. 4 preferably includes a table as shown in FIG. Table 1 is a time table, and Table 2 is a frequency table of the pump motor. In the time table of Table 1, the process number is the serial number of the step according to the process sequence of the molding process, and the number assigned to the steps of product extrusion return, high pressure mold closing, low pressure mold closing, etc. in FIG. It is attached continuously from 0. P (1) indicates step 1. The operation number is a number given to the operation of the hydraulic molding machine. Referring to Table 1, P (0), P (11), P (13) are the operation number 9, and the hydraulic molding machine is number 9. Indicates the same operation. Looking at the table in Table 1, the master column indicates the master measurement value of the operating time, and is indicated by D (i, j). D (0,1) is an operation time measurement value, i = 0 indicates a master measurement value, j = 1 indicates that the step is 1, and the operation time master measurement value in step 1 It shows that there is. In the frequency table of Table 2, the measured value of the input frequency of the pump motor is displayed as F (i, j). When F (0,1) is described, i = 0 is a master measured value. j = 1 indicates that the step is 1, indicating that it is the master measurement value of the frequency of Step 1. Further, in Table 1, D (1, j) indicates the first measured value after the master measurement. For example, D (1,2) is the first time of the operation time of step 2. It is a measured value. In Table 2, for example, E (1,2) is the first measurement value of the frequency in Step 2. For convenience, Tables 1 and 2 show only the second measured value, but these tables are adjusted and measured until all the set frequencies are determined, and the number of tables corresponding to the number of times is obtained. The operating time and frequency are preferably stored in the form of such a table. However, it may be stored in another form.

  FIG. 3 shows a second embodiment of the present invention. Referring now to the drawings, and more particularly to FIG. 3, elements of FIG. 3 that are the same as or similar to the elements of the first embodiment disclosed in FIGS. 1 and 2 are designated by the same reference numerals. ing. In the second embodiment, the hydraulic molding machine 50 includes a sub motor 61 and an inverter 63 in front of the sub motor 61 in addition to the main motor 21 corresponding to the pump motor 21 of the first embodiment. In the hydraulic molding machine 50, the main motor 21 drives three hydraulic pumps 5, 6, and 41, and the sub motor 61 drives one hydraulic pump 62. The hydraulic molding machine 50 includes control valves 45, 46, 47, and 64 for adjusting the discharge flow rate by allowing the excess flow rate to escape to the tank 4 on the discharge side of the hydraulic pumps 5, 6, 41, and 62. To do. In the second embodiment, by providing a plurality of hydraulic pumps and a plurality of hydraulic pump drive motors in this way, even when the required oil flow rate has a wide range in each molding step, energy is wasted. It is comprised so that it may decrease. In addition, by being configured with a plurality of motors and hydraulic pumps in this way, it is possible to reduce costs and reduce the size of the apparatus by not using special large motors or hydraulic pumps. There are many existing hydraulic molding machines configured in this way.

  Also in the second embodiment, it is possible to use an inverter control method including adjustment of substantially the same frequency as the adjustment step described in the first embodiment. The adjustment procedure in this case is substantially the same as in the case of the first embodiment described above, and it is easy for those skilled in the art to modify the steps accompanying the increase in the number of inverters and pump drive motors. Therefore, it is omitted to avoid duplication. As in the second embodiment, even when the number of inverters, hydraulic pump drive motors, hydraulic pumps, and control valves in the hydraulic circuit is increased or changed, the same as in the first embodiment. It should be understood that the present invention can be implemented by a method and a control device that implements the method.

Next, effects and operations of the above embodiment will be described.
The following effects can be expected from the hydraulic molding machine control method and apparatus for carrying out the same according to the first embodiment of the present invention.
・ The inverter can be used to rationally save energy without causing the hydraulic pump motor to get the required oil pressure or oil flow rate.
When energy-saving control of existing equipment is performed according to the present invention, it can be realized by measuring the operation time of the process without adding a measuring instrument, piping or wiring therefor.
・ In energy-saving control by adjusting the frequency by the inverter, in order to obtain a properly adjusted frequency, it does not require a large amount of man-hours, and the frequency is automatically obtained during operation of the equipment by a control device such as a computer. I can do it.
・ Since the adjustment process is divided into an even-numbered step adjustment process and an odd-numbered step adjustment process, it is implemented in two stages, so the influence of variations in the response delay of the inverter that occurs when moving from each single step to the next single step Is substantially eliminated.

The following effects can be expected from the control method of the hydraulic molding machine according to the second embodiment of the present invention and the apparatus for carrying out the method.
The same effects as those of the first embodiment can also be exhibited in a hydraulic molding machine that includes a plurality or many inverters, a hydraulic pump motor, a hydraulic pump, and the like.

In the above description, the apparatus of the present invention has been described as an injection molding machine, but the present invention is not limited thereto, and other molding machines may be used.
Further, the number of components of the hydraulic forming machine described above or shown in the embodiments shown in the accompanying drawings is merely an example, and may be more or less than this, and may be known. Components may be added to the hydraulic forming machine.
Further, in the above-described embodiment, it has been described as a modification of an existing conventional hydraulic molding machine. However, the scope of application of the present invention is not limited to this, and the present invention is a hydraulic molding machine that is newly manufactured. May be applied.
In the above-described embodiment, the control device 25 and the sequencer 24 have been described as separate bodies. However, they may be integrally formed, and another control element may be added.
The above-described embodiment is an example of the present invention, and the present invention is not limited by the embodiment, and is defined only by matters described in the claims, and other embodiments are also possible. It can be implemented.

FIG. 1 schematically shows the equipment configuration of a hydraulic molding machine according to a first embodiment of the present invention. FIG. 2 shows a control configuration of the hydraulic molding machine of FIG. FIG. 3 schematically shows the equipment configuration of the hydraulic molding machine according to the second embodiment of the present invention. FIG. 4 is an overall control flowchart of the hydraulic molding machine according to the first embodiment of the present invention. FIG. 5 shows a preferred measurement value table used in the inverter control method according to the first embodiment of the present invention. FIG. 6 is a graph showing a temporal change in power consumption in the hydraulic molding machine using the control method according to the first embodiment of the present invention. FIG. 7 is a graph showing temporal changes in power consumption in a conventional hydraulic molding machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydraulic molding machine 2 ... Injection arrow 3 ... Mold 4 ... Oil tank 5 ... Hydraulic pump 6 ... Hydraulic pump 7 ... Hydraulic cylinder 8 ... Hydraulic motor 9 ... Hydraulic cylinder 11 ... Throttle valve 12 ... Relief valve 21 ... Pump motor 22 ... Inverter 23 ... Power supply 24 ... Sequencer 25 ... Control device

Claims (7)

In the control method of the hydraulic molding machine,
The hydraulic molding machine is
At least one hydraulic pump;
At least one electric motor for driving the at least one hydraulic pump;
At least one inverter connected to the at least one electric motor and changing a frequency of a voltage supplied thereto;
A control device for controlling the at least one inverter to adjust a frequency of a voltage supplied from the inverter;
Comprising:
The control method is:
A master procedure for determining in advance each master operation time as a target of each unit process of the molding process,
Adjustment procedure for adjusting and setting the frequency of the supply voltage of the inverter for each unit process;
The adjustment procedure further comprises:
In each unit process, the sub-procedure for adjusting the frequency of the supply voltage of the inverter by the control device and measuring the operation time during adjustment of each unit process at that time;
For each unit process, the master operation time is compared with the adjustment operation time, and the adjustment is performed by changing the frequency of the supply voltage of the inverter to the limit frequency at which the adjustment operation time is substantially equal to the master operation time. A sub-procedure for determining a set frequency of the supply voltage of the inverter for each unit process to the limit frequency;
Sub-procedure for storing a set frequency of the supply voltage of the inverter for each unit process in the control device;
A control method characterized by the above.   2. The control according to claim 1, further comprising a step of controlling the inverter by the control device so that the inverter supplies a voltage of the set frequency in the molding step after the adjustment procedure. Method.   In the master procedure, a voltage having a predetermined frequency is supplied from the at least one inverter to the at least one electric motor, and at this time, the operation time of each unit process of the molding process performed by the hydraulic molding machine. The control method according to claim 1, wherein the master operation time of each unit process is determined by measuring the step.   4. The control method according to claim 3, wherein in the master procedure for determining the master operation time, the frequency of the supply voltage of the inverter is set to a frequency at which frequency adjustment by the inverter is not performed.   In the adjustment procedure, the frequency of the supply voltage of the inverter is adjusted and set for each unit process. In the adjustment procedure, each unit process is divided into an odd-numbered process group and an even-numbered process group. After the adjustment process is performed for the process and the set frequency for each even process is determined and stored in the control device, the adjustment process is performed for the other group of processes, in the example, the odd process, and each odd process. The control method according to any one of claims 1 to 4, wherein a set frequency is determined.   6. A hydraulic molding machine capable of executing the control method according to any one of claims 1 to 5.   A control apparatus comprising a program capable of executing the control method according to any one of claims 1 to 5.

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