JP2017136693A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold clamping device of an injection molding machine that can always drive a hydraulic pump at high efficiency.SOLUTION: A mold clamping device 1 of the present invention includes a variable volume type hydraulic pump 34 due to a change of a swash plate angle θ, and a servomotor 32 that drives the hydraulic pump 34. When a mold clamping force is set as an operation setting condition of the hydraulic pump 34, a predetermined working oil pressure corresponding to the operation setting condition, and, predetermined working oil flow rate are referenced with the pump efficiency data, the predetermined working oil pressure, and, the swash plate angle θ of the hydraulic pump 34 where a highest efficiency can be obtained when operating at the predetermined working oil flow rate, and the number of rotation N of the servomotor 32 are specified, and by the specified swash plate angle θ of the specified hydraulic pump and the number of the rotation of an electric motor, operations of the hydraulic pump 34 and the servomotor 32 are controlled.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an injection molding machine that performs high-efficiency control of a predetermined operation process in a molding cycle by variably controlling a hydraulic pump.

  Injection molding is a mold clamping process in which a pair of molds are closed and clamping is performed, an injection process in which a molten material is injected into a cavity in the mold, and a pressure holding process in which pressure is continuously applied to the injected material for a predetermined period. This is performed by performing a mold opening process for opening the mold after the injected material is solidified, a projecting process for projecting a molded product fixed to the mold, and the like. An injection molding machine that performs such injection molding includes a plurality of hydraulic actuators for performing each process and a hydraulic pressure supply device for supplying hydraulic oil to these hydraulic actuators. Then, by performing pressure control or flow rate control with the hydraulic supply device, a driving force is generated by these hydraulic actuators to perform each step.

Japanese Patent Laid-Open No. 2004-260688 variably controls the number of rotations of a drive motor that drives a hydraulic pump to control each operation process in a molding cycle, and a fixed large discharge flow rate Qm and a small flow rate smaller than the large flow rate. A hydraulic pump capable of setting a fixed discharge flow rate Qs is used, and a limit condition based on a threshold for the load state of the drive motor is set in advance. In Patent Document 1, during a molding operation, a predetermined operation process is set to a fixed discharge flow rate Qm with a large flow rate to control the operation process, and the load state of the drive motor is monitored, and the load state is a limit condition. Is reached, the flow rate is switched to a fixed discharge flow rate Qs with a small flow rate.
According to the control method of Patent Document 1, it is possible to set an optimum threshold value (limit condition) for the drive motor while avoiding overload of the drive motor. Accordingly, it is possible to avoid an inconvenience that an unnecessary load is applied to the drive motor and, consequently, the hydraulic pump and the energy consumption increases, and an optimum operation state can be set.

JP 2009-285972 A

Patent Document 1 sets a limit condition for switching the fixed discharge amount of the pump in consideration of a predetermined margin before the load pressure or load time at which the servo motor stops due to overload. Therefore, even if an excessive load occurs due to some abnormality or the time of a predetermined operation process becomes long, a servo motor stop (trip) occurs due to overload, and an unnecessary burden is applied. Can be avoided. However, in Patent Document 1, the discharge flow rate Qs with a small flow rate is set to a discharge amount that does not trip even at a high load and for a long time, and the discharge flow rate Qm with a large flow rate is fixed to a discharge flow with a small flow rate fixed. The discharge amount is only set to about twice the flow rate Qs. By the way, normally, the energy consumption efficiency of the pump changes with respect to the operating conditions, specifically, the discharge flow rate and the discharge pressure. Therefore, in Patent Document 1, particularly in the case of a fixed discharge flow rate Qm with a large flow rate, there is a case where energy is wasted by operating under a low efficiency operation condition in terms of the operation efficiency of the pump.
Therefore, an object of the present invention is to provide a mold clamping device for an injection molding machine that can always drive a hydraulic pump with high efficiency.

The present invention is a mold clamping device that includes a hydraulic actuator and a hydraulic pressure supply unit that operates by supplying hydraulic oil to the hydraulic actuator, and operates the hydraulic actuator to clamp a pair of molds. The hydraulic pressure supply unit includes a variable displacement hydraulic pump by changing the swash plate angle θ, an electric motor that drives the hydraulic pump, and a control unit that variably controls the rotational speed N of the electric motor.
When the operation setting condition of the hydraulic actuator is set, the control unit of the present invention sets the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow corresponding to the operation setting condition, the hydraulic pump operation condition, and the hydraulic pump operation. Compared with the pump efficiency data associated with the efficiency, the swash plate angle θ of the hydraulic pump and the electric motor that can obtain the maximum efficiency when operating at a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. The rotation speed N is specified, and the operation of the hydraulic pump and the electric motor is controlled by the specified swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor.

  In the injection molding machine of the present invention, the pump efficiency data is corrected efficiency data obtained by adding the efficiency data of the electric motor to the operating efficiency data of the hydraulic pump alone or the operating efficiency data of the hydraulic pump alone. Can be used.

  In the injection molding machine of the present invention, the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate can include a preset discharge hydraulic pressure ρ and a preset discharge flow rate Qn. In this case, the preset discharge hydraulic pressure ρ can be set as the discharge hydraulic pressure ρc calculated from the operation setting conditions, and the preset discharge flow rate Qn can be set as the discharge flow rate Qns not depending on the operation setting conditions. Alternatively, the preset discharge hydraulic pressure ρ may be the discharge hydraulic pressure ρc calculated from the operation setting condition, and the preset discharge flow rate Qn may be the discharge flow rate Qnc calculated from the operation setting condition.

  In the injection molding machine of the present invention, the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate may include a detected discharge hydraulic pressure ρd and a preset discharge flow rate Qn. In this case, the preset discharge flow rate Qn can be the discharge flow rate Qns not depending on the operation setting condition, or can be the discharge flow rate Qnc calculated from the operation setting condition.

  In the injection molding machine of the present invention, it is possible to provide a storage unit for storing the pump efficiency data for each of a plurality of different swash plate angles θ, the control unit for each pump efficiency data of the plurality of swash plate angles θ, By comparing the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate, the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that can obtain the highest efficiency can be specified.

  In the injection molding machine of the present invention, the control unit stores pump efficiency data at the swash plate angle not stored in the storage unit, and the pump efficiency data of the swash plate angle θ and swash plate angle θ stored in the storage unit. The pump efficiency data obtained by this interpolation calculation is compared with the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate to obtain the maximum efficiency of the swash plate angle θ of the hydraulic pump, And the rotation speed N of an electric motor can be specified.

  In the injection molding machine of the present invention, the control unit includes a predetermined first hydraulic pressure ρ1 and a predetermined first set flow rate Q1 as a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. A first operating condition, and a second operating pressure consisting of a preset second set hydraulic pressure ρ2 (where ρ2> ρ1) and a preset second set flow rate Q2 (where Q2 <Q1). Until the detected discharge hydraulic pressure ρd reaches the first set hydraulic pressure ρ1, the first operating condition and the pump efficiency data are collated to identify the swash plate angle θ1 of the hydraulic pump and the rotational speed N1 of the electric motor. , Control the operation of the hydraulic pump and the electric motor, and collate the second operating condition with the pump efficiency data until the detected discharge hydraulic pressure ρd exceeds the first set hydraulic pressure ρ1 and reaches the second set hydraulic pressure ρ2. Pump swash plate angle θ2 and electric The operation of the hydraulic pump and the electric motor can be controlled by specifying the rotation speed N2 of the motor.

  In the injection molding machine of the present invention, the control unit includes a predetermined first hydraulic pressure ρ1 and a predetermined first set flow rate Q1 as a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. A first operating condition, and a second operating pressure consisting of a preset second set hydraulic pressure ρ2 (where ρ2> ρ1) and a preset second set flow rate Q2 (where Q2 <Q1). Until the detected discharge oil pressure ρd reaches the first set oil pressure ρ1, the detected discharge oil pressure ρd, the first set flow rate Q1 and the pump efficiency data are collated, and the swash plate angle θ1 of the hydraulic pump, and The rotational speed N1 of the electric motor is specified to control the operation of the hydraulic pump and the electric motor, and the detected discharge hydraulic pressure ρd exceeds the first set hydraulic pressure ρ1 and reaches a second set hydraulic pressure ρ2 set in advance. The detected discharge hydraulic pressure ρd and The operation of the hydraulic pump and the electric motor can be controlled by collating the two set flow rates Q2 with the pump efficiency data and specifying the swash plate angle θ2 of the hydraulic pump and the rotation speed N2 of the electric motor. .

  In the injection molding machine of the present invention, the first set hydraulic pressure ρ1 set in advance is the first set hydraulic pressure ρ1c calculated from the operation setting conditions, and the first set flow rate Q1 set in advance is not based on the operation setting conditions. In addition to the first set flow rate Q1s, the second set hydraulic pressure ρ2 set in advance is equal to or higher than the first set hydraulic pressure ρ1 and is set as the second set hydraulic pressure ρ2c calculated from the operation setting conditions. The set flow rate Q2 may be a first set flow rate Q1 or less and a second set flow rate Q2s that does not depend on the operation setting conditions.

  In the injection molding machine of the present invention, the first set hydraulic pressure ρ1 set in advance is set as the first set hydraulic pressure ρ1c calculated from the operation setting conditions, and the first set flow rate Q1 set in advance is calculated from the operation setting conditions. In addition to the first set flow rate Q1c, the second set hydraulic pressure ρ2 set in advance is set as the second set hydraulic pressure ρ2c calculated from the operation set conditions, and the second set flow rate Q2 set in advance is set from the operation set conditions. The calculated second set flow rate Q2c can also be used.

In the injection molding machine of the present invention, the control unit includes a first set hydraulic pressure ρ1p obtained by calculation as a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate, and a first set flow rate Q1p obtained by the calculation. And a second operating condition consisting of a second set hydraulic pressure ρ2p determined by calculation and a second set flow rate Q2p determined by calculation.
Then, the control unit collates the first operation condition with the pump efficiency data until the detected position L1 of the movement target of the hydraulic actuator reaches the operation switching position Ls, and the swash plate angle θ1 of the hydraulic pump, and The rotation speed N1 of the electric motor is specified, and the operation of the hydraulic pump and the electric motor is controlled. Until the detected position L1 of the moving object reaches the operation completion position Lc, the second operating condition and the pump The operation of the hydraulic pump and the electric motor can be controlled by collating the efficiency data and specifying the swash plate angle θ2 of the hydraulic pump and the rotation speed N2 of the electric motor.

  In this injection molding machine, when the hydraulic pump generates a clamping force on the movable mold via the tie bar, the set clamping force and the hydraulic pressure necessary to generate the clamping force are set. Clamping force-discharge hydraulic pressure conversion data, which is data associated with the pump discharge hydraulic pressure, the predetermined operating speed set, and the hydraulic pump discharge flow rate required to operate the tie bar at the moving speed And a storage unit for storing speed-discharge flow rate conversion data, which is data associated with. Then, when the first mold clamping force F1 is set, the control unit obtains the first set hydraulic pressure ρ1p with reference to the mold clamping force-discharge hydraulic pressure conversion data, and when the first mold clamping speed V1 is set, With reference to the speed-discharge flow rate conversion data, the first set flow rate Q1p is obtained, and when the second mold clamping force F2 is set, the mold setting force-discharge hydraulic pressure conversion data is referred to and the second set hydraulic pressure ρ2p is determined. Then, when the second mold clamping speed V2 is set, the second set flow rate Q2p can be obtained by referring to the speed-discharge flow rate conversion data.

  According to the injection molding machine of the present invention, the servo motor and the hydraulic pump can be operated under the highest efficiency operating condition corresponding to the set operation setting condition of the hydraulic actuator, so that the hydraulic pump can always be operated with high efficiency. In addition, according to the injection molding machine of the present invention, the high-efficiency operation conditions are set based on the pump efficiency data prepared for the hydraulic pump in advance, so the high-efficiency operation conditions are accurately set. can do.

It is a figure which shows schematic structure of the mold clamping apparatus of the injection molding machine which concerns on embodiment of this invention. It is a block diagram which shows the structure of the hydraulic pressure supply part of the mold clamping apparatus in 1st Embodiment. It is a block diagram which shows the structure of the molding machine control part of the mold clamping apparatus in 1st Embodiment. It is a figure which shows an example of the pump efficiency data (swash plate angle (theta) x) used in 1st Embodiment. It is a figure which shows an example of the pump efficiency data (swash plate angle (theta) y) used in 1st Embodiment. It is a figure which shows an example of the pump efficiency data (swash plate angle (theta) z) used in 1st Embodiment. 5 is a flowchart illustrating a procedure of a pressure increasing process performed based on a combination of a swash plate angle θ and a rotational speed N at which the maximum efficiency Em is obtained using pump efficiency data in the first embodiment. In 1st Embodiment, it is a figure explaining the procedure which specifies highest efficiency Em1 in setting oil pressure (rho) 1 and setting rotation speed N1. In 1st Embodiment, it is a figure explaining the procedure which specifies highest efficiency Em2 in setting oil pressure (rho) 2 and setting rotation speed N2. It is a figure which shows an example of the motor efficiency data used in 2nd Embodiment. It is a figure showing integrating | accumulating the pump efficiency data and motor efficiency data which are used in 2nd Embodiment. FIG. 10 is a part of a flowchart showing a procedure of a pressure increasing process performed based on a combination of a swash plate angle θ and a rotational speed N at which the maximum efficiency Em is obtained using the pump efficiency data in the third embodiment. In 3rd Embodiment, it is another one part of the flowchart which shows the procedure of the pressure | voltage rise process performed based on the combination of swash plate angle (theta) and the rotation speed N which can obtain the maximum efficiency Em using pump efficiency data. It is a flowchart which shows the procedure of the pressure | voltage rise process performed based on the combination of swash plate angle | corner (theta) and the rotation speed N in which the maximum efficiency Em is obtained using pump efficiency data in 4th Embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an injection molding machine according to the present invention will be described with reference to the accompanying drawings, taking a mold clamping device 1 as an example for the sake of simplicity.
[First Embodiment]
The mold clamping device 1 according to the present embodiment is obtained in advance by experiments or simulations such as numerical analysis on the hydraulic pump when operating the servo motor and the hydraulic pump under high-efficiency operating conditions in the boosting step. By using the pump efficiency data, highly efficient operation conditions can be set with high accuracy. Hereinafter, the configuration of the mold clamping device 1 and the procedure of the pressure increasing process in the mold clamping device 1 will be described in order.

[Configuration of mold clamping device 1]
As shown in FIGS. 1 and 2, the mold clamping apparatus 1 according to the present embodiment includes a pair of a fixed mold 14 and a movable mold 15, and a fixed mold 14 and a movable mold for obtaining a molded product having a desired shape. An injection cylinder 19 for injecting molten resin as an injection material into a cavity formed between the mold 15, a mold clamping cylinder 18 for generating a driving force for mold clamping, and hydraulic oil to the mold clamping cylinder 18 And a molding machine control unit 50 for controlling various configurations.

As shown in FIG. 1, in the mold clamping device 1, a fixed die plate 12 that holds a fixed mold 14 is fixed on the upper surface of one end side of the base frame 11.
On the upper surface on the other end side of the base frame 11, a movable die plate 13 that holds the movable mold 15 is disposed so as to be movable forward and backward, facing the fixed die plate 12. A guide rail 26 is laid on the base frame 11, and a linear bearing 27 guided by the guide rail 26 supports the movable die plate 13 via a slide base 28. Note that the movable die plate 13 may be supported via the slide table 28 using a sliding plate instead of the linear bearing 27.
The fixed die plate 12 is provided with four hydraulic clamping cylinders 18 having small strokes and large cross-sectional areas at the four corners. Note that the mold clamping cylinder 18 may be provided on the movable die plate 13. One end of a tie bar 17 is connected to one side of each ram 16 that slides in the mold clamping cylinder 18, and the tie bar 17 opens to the movable die plate 13 when the opposing movable die plate 13 approaches to close the mold. The four insertion holes thus formed are penetrated.
A hydraulic oil pipe 40 (described later) is connected to the mold clamping cylinder 18, and the hydraulic oil pipe 40 supplies oil to the mold clamping side chamber 181 and the mold opening side chamber 182 of the mold clamping cylinder 18.

It is installed parallel to the moving direction of the moving die plate 13 and is supported by a bearing box 20 held on the fixed die plate 12 and a bearing box 21 held on the base frame 11 so as to be rotatable and restrained in the axial direction. The moving means of the moving die plate 13 is constituted by the ball screw shaft 25 driven by the servo motor 22 through the power transmission gears 23 and 24. The rotational speed and rotational speed of the ball screw shaft 25 are controlled via a servo motor 22 by a control device (not shown).
The other end of each tie bar 17 is formed with a plurality of ring-shaped parallel grooves (or spiral thread grooves) with an equal pitch. A half nut 29 that meshes with the ring-shaped parallel groove of each tie bar 17 is provided on the back surface of the movable die plate 13.

  The mold clamping device 1 described above is a servo motor from the state where the fixed mold 14 and the movable mold 15 are opened to the state where the fixed mold 14 and the movable mold 15 are closed as shown in FIG. The moving die plate 13 is moved by the rotation of the ball screw shaft 25 driven by the motor 22. The movable die plate 13 stops when the opposed surfaces of the fixed mold 14 and the movable mold 15 come into contact with each other.

  The half nut 29 is actuated at the stop position of the movable die plate 13 so that the ring-shaped parallel groove inside the half nut 29 engages with the ring-shaped parallel groove at the tip of the tie bar 17 and the tie bar 17 and the half nut 29 are engaged. And combine. Thereafter, the mold clamping side chamber 181 of the mold clamping cylinder 18 is pressurized and clamped. After performing the mold clamping in this way, the molten resin is injected from the injection cylinder 19 into a cavity formed by the fixed mold 14 and the movable mold 15 to mold a molded product.

As shown in FIG. 2, the hydraulic pressure supply unit 30 includes a hydraulic pressure source 31 that supplies hydraulic oil, a hydraulic oil pipe 40 that is connected to the hydraulic power source 31, and a pressure detector 41 that is provided in the hydraulic oil pipe 40. .
The molding machine control unit 50 also serves as a control unit that determines the flow rate and pressure during operation / stop and operation of the hydraulic pressure source 31 in the hydraulic pressure supply unit 30.

  The hydraulic source 31 includes a servo motor 32, a servo control circuit 33 that can variably control the rotation speed of the servo motor 32, a hydraulic pump 34 that is driven by the rotation of the servo motor 32 to discharge hydraulic oil, and a hydraulic pump 34. A discharge pipe 39 through which hydraulic oil discharged from the pipe flows, and a swash plate angle control unit 37 that controls the operation of the hydraulic pump 34. The discharge pipe 39 is connected to the hydraulic oil pipe 40.

  The servo motor 32 has an encoder that detects the rotation angle, and outputs the detected rotation angle to the servo control circuit 33. The servo control circuit 33 generates a pulse signal corresponding to the rotation speed N command value input from the molding machine controller 50 and outputs the pulse signal to the servo motor 32 to drive the servo motor 32 to rotate at the rotation speed N. The rotation angle detected by the encoder of the servo motor 32 is continuously input to the servo control circuit 33, and the servo control circuit 33 can obtain the rotation speed N while performing feedback correction based on the rotation angle. The servo motor 32 is controlled.

  Here, as long as the servo motor 32 is a motor that can be used for controlling the position, speed, etc. in the servo mechanism, the type of the motor is arbitrary, and an AC servo motor, a DC servo motor, a stepping motor, etc. can be applied. . Regarding the structure, for example, the stator structure may be either a distributed winding type or a concentrated winding type, and the rotor structure may be either a surface magnet affixed type (SPM) motor or an internal magnet embedded type (IPM) motor.

The hydraulic pump 34 in the present embodiment is a variable displacement pump, and can be rotated by the servo motor 32 around the central axis at a constant rotational speed, and the inclination angle with respect to the central axis can be changed. A piston (not shown) that strokes according to the rotation of the plate 35 to discharge the hydraulic oil and an angle detector 45 that detects the angle of the swash plate 35 are provided.
The swash plate angle control unit 37 operates the angle adjustment unit 36 based on the swash plate angle θ command input from the molding machine control unit 50 to adjust the angle of the swash plate 35. Based on the detection result, the inclination angle of the swash plate 35 is feedback-controlled.
Although not shown, the angle adjustment unit 36 includes, for example, a spring that urges the swash plate 35, a hydraulic angle adjustment actuator that changes the inclination angle of the swash plate 35 against the urging of the spring, and a hydraulic pressure And an electromagnetic direction switching valve for controlling the supply of oil to the actuator.

  As shown in FIG. 3, the molding machine control unit 50 that also serves as a hydraulic control unit in the hydraulic supply unit 30 includes an input unit 51 that inputs control set values, and control values that generate control values for the servo motor 32 and the hydraulic pump 34. A generation unit 53, a command output unit 55 that obtains control values for the servo motor 32 and the hydraulic pump 34 from the control value generation unit 53, generates a control command, and outputs the generated control command, and generates a control value. And a storage unit 57 in which various data necessary for the storage are stored.

The storage unit 57 stores pump efficiency data related to the hydraulic pump 34.
The pump efficiency data indicates that the tie bar 17 is operated by applying a predetermined speed and a predetermined hydraulic pressure in order to obtain a set clamping pressure when the movable mold 15 and the fixed mold 14 are clamped. This is used to determine the combination of the swash plate angle θ and the rotational speed N at which the highest efficiency Em is obtained from among a plurality of combinations of the swash plate angle θ and the rotational speed N of the hydraulic pump 34 required for the above.
The pump efficiency data is obtained by associating the operating conditions of the hydraulic pump 34 with the operating efficiency of the hydraulic pump 34, and is acquired in advance for the hydraulic pump 34. For example, as shown in FIGS. Operating conditions and operating efficiency are associated with each other at swash plate angles θx, θy, and θz. 4 is a correlation diagram between operation conditions and operation efficiency at the swash plate angle θx, FIG. 5 is a correlation diagram between operation conditions and operation efficiency at the swash plate angle θy, and FIG. 6 is a correlation diagram between operation conditions and operation efficiency at the swash plate angle θz. Respectively. The first horizontal axis on the lower side in each figure indicates the discharge flow rate Q of hydraulic oil discharged from the hydraulic pump 34, and the first vertical axis on the left side in the figure indicates the discharge hydraulic pressure ρ of oil discharged by the hydraulic pump 34. This is map-like data in which the efficiency of the hydraulic pump 34 is indicated by contour lines on two-dimensional coordinates. The second horizontal axis of the two-dimensional coordinates indicates the rotational speed N of the hydraulic pump 34, and the second vertical axis indicates the input torque T of the hydraulic pump 34.

The pump efficiency data is acquired for each swash plate angle of the hydraulic pump 34. In this embodiment, as shown in FIGS. 4 to 6, three different swash plate angles θx, θy, and θz are shown. This is only an example, and the swash plate angle can be increased to four or more.
In this embodiment, map-like data that is easy to understand visually is taken as an example of pump efficiency data. However, in the present invention, the data format is arbitrary as long as the same function can be achieved, and data in table format. Alternatively, the data may be a functional expression.

  When the discharge flow rate Q and the discharge hydraulic pressure ρ are specified in the pump efficiency data shown in FIGS. 4 to 6, the efficiency E of the hydraulic pump 34 can be specified. The efficiency E is specified for each pump efficiency data of the swash plate angles θx, θy, and θz, and any of the swash plate angles θx, θy, and θz from which the maximum efficiency Em is obtained, and the swash plate angle θ The rotational speed N is specified. Then, the hydraulic pump 34 is operated at the specified swash plate angle θ, and the servo motor 32 is operated at the specified rotational speed N. It is to be noted that the higher the efficiency E is, the less energy is consumed when the hydraulic pump 34 is operated.

  In addition, the storage unit 57 includes mold clamping force-discharge hydraulic pressure conversion data in which the set mold clamping force F and the discharge hydraulic pressure ρ of the hydraulic pump 34 necessary for generating the mold clamping force F are associated with each other. In addition, speed-discharge flow rate conversion data in which the predetermined speed set and the discharge flow rate Q of the hydraulic pump 34 necessary to operate the tie bar 17 at the speed are associated with each other is stored. The conversion data is arbitrary, for example, map data, table format data, or the like.

[Procedure for pressurization process]
The procedure for determining the combination of the swash plate angle θ and the rotational speed N that can obtain the maximum efficiency Em using the pump efficiency data will be further described with reference to FIGS. This procedure relates to a so-called pressure increasing process for clamping the movable mold 15 and the fixed mold 14, and is performed while detecting the discharge hydraulic pressure ρ from the hydraulic pump 34. Then, a threshold value (ρ1) is provided for the discharge hydraulic pressure ρ, and the operating conditions of the hydraulic pump 34 are changed before and after reaching the set hydraulic pressure ρ1. Before reaching the set hydraulic pressure ρ1, the discharge flow rate Q is increased to speed up the operation of the clamping cylinder 18, and after reaching the set hydraulic pressure ρ1, the discharge flow rate Q is decreased to clamp the mold by the clamping cylinder 18. Is assumed to be large.

  First, when a mold clamping force F as an operation setting condition is input as a control set value to the input unit 51 of the molding machine control unit 50 (S101 in FIG. 7), the control value generating unit 53 acquires the mold clamping force F. The discharge hydraulic pressure ρ of the hydraulic pump 34 required to generate the mold clamping force F is obtained by referring to the mold clamping force-discharge hydraulic pressure conversion data stored in the storage unit 57. At the same time, the discharge flow rate Q necessary for operating the tie bar 17 at a predetermined speed is obtained by referring to the speed-discharge flow rate conversion data (S103 in FIG. 7). The discharge hydraulic pressure ρ and the discharge flow rate Q (set operation conditions) obtained here are expressed as a set hydraulic pressure ρ1 and a set flow rate Q1 in order to distinguish them from those obtained later. At this time, the set hydraulic pressure ρ1 is obtained by calculation from the mold clamping force F set as the molding condition, and the set flow rate Q1 is set to a predetermined fixed value that does not depend on the molding condition. Accordingly, the set hydraulic pressure ρ1 corresponds to the discharge hydraulic pressures ρc and ρ1c in the present invention, and the set flow rate Q1 corresponds to the discharge flow rates Qns and Q1s in the present invention. The set hydraulic pressure ρ1 is the threshold value described above, and a value lower than the mold clamping force F is adopted.

  When the control value generating unit 53 obtains the set hydraulic pressure ρ1 and the set flow rate Q1 (first set hydraulic pressure, first set flow rate, first operating condition), it refers to the pump efficiency data stored in the storage unit 57. Thus, the operating condition that maximizes the operating efficiency of the hydraulic pump 34 is selected (S105 in FIG. 7). In this selection, in the pump efficiency data stored in the storage unit 57, the efficiency E corresponding to the set hydraulic pressure ρ1 and the set flow rate Q1 is obtained for each pump efficiency data of the swash plate angles θx, θy, and θz. Is determined by specifying any of the swash plate angles θx, θy, and θz from which the maximum efficiency Em is obtained, and the rotational speed N at the swash plate angle θ. The swash plate angle θ and the rotation speed N selected here are expressed as a set angle θ1 and a set rotation speed N1 in order to distinguish them from those obtained later.

  For example, in FIGS. 8A, 8B, and 8C showing the correlation between the operation conditions and the operation efficiency at the swash plate angles θx, θy, and θz, the hydraulic pump 34 at the set hydraulic pressure ρ1 and the set rotational speed N1 is shown. Since the swash plate angles θx, θy, and θz are 88%, 89%, and 87%, respectively, the maximum efficiency Em1 is 89%, and the rotational speed N and the swash plate angle at which this maximum efficiency Em1 is obtained. The combination of θ is the set rotation speed N1 and the swash plate angle θy. The swash plate angle θy is set as the set angle θ1.

When the set rotational speed N1 and the set angle θ1 at which the maximum efficiency Em1 is obtained are obtained in this way, the command output unit 55 acquires the control value from the control value generating unit 53, and also sets the set rotational speed N1 and the set angle θ1. An operation command value is generated for each. The command output unit 55 outputs a command value CN1 corresponding to the set rotational speed N1 to the servo control circuit 33 of the hydraulic pressure supply unit 30, and outputs a command value Cθ1 corresponding to the set angle θ1 to the swash plate angle of the hydraulic pressure supply unit 30. Output to the control unit 37.
The servo control circuit 33 controls the rotation speed N of the servo motor 32 based on the acquired command value CN1, and the swash plate angle control unit 37 operates the angle adjustment unit 36 based on the acquired command value Cθ1. The swash plate 35 of the hydraulic pump 34 is set to the set angle θ1.

As described above, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em1 is obtained (S107 in FIG. 7), and the clamping pressure between the fixed mold 14 and the movable mold 15 is increased (S109 in FIG. 7). ).
In the process of increasing the pressure of the mold, the pressure detector 41 of the hydraulic pressure supply unit 30 detects the discharge hydraulic pressure ρ of the hydraulic oil flowing in the hydraulic oil pipe 40, and the detected value is detected as the detected discharge hydraulic pressure ρd. To do. The detected discharge hydraulic pressure ρd is sent from the pressure detector 41 to the control value generation unit 53 of the molding machine control unit 50. The control value generation unit 53 that has acquired the detected discharge hydraulic pressure ρd determines whether the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ1. The comparison of whether or not is continuously performed (S111 in FIG. 7). If the detected discharge hydraulic pressure ρd has not reached the set hydraulic pressure ρ1, the control value generation unit 53 does not give an instruction to the command output unit 55, so the servo motor 32 and the hydraulic pump 34 continue to operate under the previous conditions ( FIG. 7 S111 No).

  On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ1, the control value generating unit 53 performs a process of switching the set angle θ1 and the set rotational speed N1. That is, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ1, the control value generation unit 53 refers to the mold clamping force / discharge hydraulic pressure conversion data stored in the storage unit 57 to obtain the set hydraulic pressure ρ2. At the same time, the set flow rate Q2 necessary for operating the tie bar 17 at a predetermined speed is newly specified with reference to the speed-discharge flow rate conversion data (S115 in FIG. 7). The set oil pressure ρ2 is equal to the set mold clamping force F, and the set flow rate Q2 is smaller than the set flow rate Q1. At this time, the set hydraulic pressure ρ2 is obtained by calculation from the mold clamping force F set as the operation setting condition, and the set flow rate Q2 is set to a predetermined fixed value regardless of the molding condition. Accordingly, the set hydraulic pressure ρ2 corresponds to the discharge hydraulic pressures ρc and ρ2c in the present invention, and the set flow rate Q2 corresponds to the discharge flow rates Qns and Q2s in the present invention.

When the control value generating unit 53 obtains the set oil pressure ρ2 and the set flow rate Q2 (second set oil pressure, second set flow rate, second operation condition), it refers to the pump efficiency data stored in the storage unit 57. Thus, the operating condition that provides the highest operating efficiency of the hydraulic pump 34 is selected (S117 in FIG. 7). This selection is performed in the same manner as the procedure for selecting the set angle θ1 and the set rotation speed N1. The selected swash plate angle θ and rotation speed N are expressed as set angle θ2 and set rotation speed N2.
For example, in FIGS. 9A, 9B, and 9C showing the correlation between the operating conditions and the operating efficiency at the swash plate angles θx, θy, and θz, the hydraulic pump 34 at the set hydraulic pressure ρ2 and the set rotational speed N2 is shown. The operating efficiency is that the swash plate angles θx, θy, and θz are 80%, 70%, and 70%, respectively, so that the maximum efficiency Em2 is 80%, and the rotational speed N and the swash plate angle at which this maximum efficiency Em2 is obtained. The combination of θ is the set rotation speed N2 and the swash plate angle θx. The swash plate angle θx is set as the set angle θ2.

  If the set rotational speed N2 and the set angle θ2 (θx) that can obtain the maximum efficiency Em2 are specified, the command output unit 55 supplies the command value CN2 corresponding to the set rotational speed N2 with hydraulic pressure in the same manner as described above. The controller 30 outputs the command value Cθ2 corresponding to the set angle θ2 to the swash plate angle controller 37 of the hydraulic pressure supply unit 30. The servo control circuit 33 controls the rotation speed N of the servo motor 32 based on the acquired command value CN2, and the swash plate angle control unit 37 operates the angle adjustment unit 36 based on the acquired command value Cθ2. The swash plate 35 of the hydraulic pump 34 is set to the set angle θ2 (S117 in FIG. 7).

As described above, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em2 is obtained (S117 in FIG. 7), and the clamping pressure between the fixed mold 14 and the movable mold 15 is increased (S119 in FIG. 7). ).
The control value generation unit 53 continuously acquires the detected discharge hydraulic pressure ρd and continuously compares whether or not the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ2 (S121 in FIG. 7). If the detected discharge hydraulic pressure ρd does not reach the set hydraulic pressure ρ2, the servo motor 32 and the hydraulic pump 34 continue to operate under the previous conditions (No in FIG. 7 S121).

  On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ2, the control value generating unit 53 determines whether or not the pressure increasing process should be completed (S121 Yes in FIG. 7). That is, the control value generator 53 determines whether or not the detected discharge hydraulic pressure ρd overshoots the set hydraulic pressure ρ2 (S123 in FIG. 7). For example, an allowable range Δρ is set, and if the detected discharge oil pressure ρd exceeds the set oil pressure ρ2 + allowable range Δρ, it is determined as an overshoot (Yes in FIG. 7), and the detected discharge oil pressure ρd is (set oil pressure ρ2 + allowable range Δρ). If it is below, it determines with not having reached overshoot (FIG. 7, S123 No).

  When the control value generator 53 determines that the detected discharge hydraulic pressure ρd is an overshoot, the control value generator 53 sets the set rotational speed N2 of the servo motor 32 to a predetermined rotational speed Ns (where Ns < The command output unit 55 sends the received command value CNs to the servo control circuit 33 of the hydraulic pressure supply unit 30. The servo motor 32 is operated based on the command value CNs. In order to reduce the hydraulic pressure, instead of lowering the set rotational speed N2 of the servo motor 32 to the rotational speed Ns, the servo motor 32 may be temporarily stopped or reversely rotated, or a predetermined valve (not shown) is opened. The hydraulic pressure in the discharge pipe 39 may be reduced. Thereafter, it is continuously determined whether or not the detected discharge hydraulic pressure ρd overshoots the set hydraulic pressure ρ2 (S125 in FIG. 7).

  On the other hand, when the control value generation unit 53 determines that the overshoot has not been reached, the control value generation unit 53 sends a command to the command output unit 55 to stop the operation of the servo motor 32, and the command output unit 55 receives this command. Then, the servo control circuit 33 is instructed to stop the servo motor 32. Thereby, the operation of the servo motor 32 is stopped, and the pressure increasing process is ended (S127 in FIG. 7). Thereafter, an injection / pressure holding process is performed in which molten resin is injected from the injection cylinder 19 into a cavity formed by the fixed mold 14 and the movable mold 15 and the resin pressure in the cavity is maintained after the injection is completed.

The mold clamping device 1 described above has the following effects.
The mold clamping device 1 has a servo motor 32 under the conditions of discharge hydraulic pressure ρ (ρ1, ρ2) and swash plate angle θ (θ1, θ2) that can be operated at the highest efficiency (Em1, Em2) according to the set mold clamping force F. Since the hydraulic pump 34 can be operated, the hydraulic pump 34 can always be driven with high efficiency.
In addition, since the mold clamping apparatus 1 sets the conditions for this highly efficient operation based on the pump efficiency data created for the hydraulic pump 34 in advance, the conditions for the highly efficient operation can be set with high accuracy. it can.

  Further, the mold clamping device 1 sets the discharge hydraulic pressure ρ in two stages of the set hydraulic pressure ρ1 and the set hydraulic pressure ρ2, and the operating conditions of the servo motor 32 and the hydraulic pump 34 depend on whether or not the discharge hydraulic pressure ρ reaches the set hydraulic pressure ρ1. Is switched. Therefore, in the boosting step, maximum efficiency Em1 and Em2 are obtained in each of the period of the first operating condition in which the hydraulic pump 34 is required to operate at high speed and the period of the second operating condition in which subsequent high-pressure operation is required. The servo motor 32 and the hydraulic pump 34 can be operated at the set rotation speeds N1 and N2 and the set angles θ1 and θ2. As a result, the hydraulic pump 34 is operated under a combination of conditions with the highest efficiency corresponding to each of the operating states of the hydraulic pump 34, so that energy consumption can be minimized.

  In the present embodiment, the present invention has been described by taking the mold clamping process of the mold clamping apparatus 1 in the injection molding machine as an example, but the present invention is applied to the hydraulic control of the pressure holding process from the final stage of the injection filling process of the injection apparatus (not shown). You can also Specifically, the set oil pressure ρ2 can be set as a discharge pressure in the pressure-holding process, which is a molding setting condition, and the set oil pressure ρ1 can be set to an arbitrary pressure value lower than the set oil pressure ρ2. In this case, when the discharge hydraulic pressure ρ reaches the set hydraulic pressure ρ2, switching control of the process of switching from the injection filling process to the pressure holding process is performed.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described.
In the second embodiment, the operating conditions of the hydraulic pump 34 are set in consideration of the operating efficiency of the servo motor 32 in addition to the operating efficiency of the hydraulic pump 34 of the first embodiment. Hereinafter, the mold clamping apparatus 2 according to the second embodiment will be described with reference to FIG. The configuration of the mold clamping device 2 is substantially the same as that of the mold clamping device 1, and the difference is that data relating to the efficiency of the servo motor 32 is added to the storage unit 57 and a control value is generated based on the added data. Since the processing is performed in the unit 53 and the command output unit 55, the description of the configuration of the mold clamping device 2 is omitted.

  In the mold clamping device 2, motor efficiency data related to the servomotor 32 is stored in the storage unit 57 of the molding machine control unit 50. The motor efficiency data includes efficiency data as a single motor shown in FIG. 10 (a), efficiency data related to the amplifier shown in FIG. 10 (b), and overall efficiency data shown in FIG. 10 (c). . Since the servo motor 32 includes a motor main body and a servo amplifier that controls the supply of power to the motor main body, the motor efficiency data also includes motor data related to the motor main body and amplifier data related to the servo amplifier. Comprehensive efficiency data includes both motor data and amplifier data. All the data are map-like data that can specify the efficiency E when the rotation speed N of the servo motor 32 and the output torque T of the servo motor 32 are specified. In the second embodiment, total efficiency data is used.

In the second embodiment, the storage unit 57 of the molding machine control unit 50 further stores efficiency data obtained by integrating the total efficiency data with the pump efficiency data (hereinafter referred to as pump unit efficiency data). .
For example, in the overall efficiency data of FIG. 10C, the efficiency when the rotational speed N is 1000 rpm and the output torque T is 200 Nm is 86 to 88%. For example, in the pump efficiency data shown in FIG. 4, the pump efficiency when the rotational speed N (second horizontal axis) is 1000 rpm and the input torque T (second vertical axis) is 200 Nm is 88%. The pump unit efficiency in this case is determined by the product (75.7 to 77.4%) of 86 to 88% which is the efficiency in the overall efficiency data and 88% which is the efficiency in the pump efficiency data. This integration is performed for the entire region of the rotational speed N and output torque T in the overall efficiency data and the entire region of the rotational speed N and input torque T at the swash plate angle θx, thereby obtaining pump unit efficiency data at the swash plate angle θx. . Similarly, pump unit efficiency data is obtained for the pump efficiency data at the swash plate angle θy and the swash plate angle θz, and these are stored in the storage unit 57. The pump unit efficiency data can be regarded as correction efficiency data obtained by adding the efficiency of the servo motor 32 to the pump efficiency data. This integration flow is shown in FIG.

  Now, a procedure for determining a combination of the swash plate angle θ and the rotational speed N that can obtain the maximum efficiency Em using the pump unit efficiency data will be described. This procedure is the same as FIG. 7 described in the first embodiment, but is referred in the procedure for selecting the highest efficiency Em1 (FIG. 7 S105) and the procedure for selecting the highest efficiency Em2 (FIG. 7 S117). The difference is that the data to be is pump unit efficiency data. Thereafter, the operation of the servo motor 32 and the hydraulic pump 34 is controlled using the set rotation speed N1, the set rotation speed N2, the set angle θ1, and the set angle θ2 selected with reference to the pump unit efficiency data.

  According to the second embodiment, not only the efficiency of the hydraulic pump 34 but also the efficiency of the servo motor 32 that drives the hydraulic pump 34 is taken into account, so that the maximum efficiency in consideration of the entire pump unit including the servo motor 32 and the hydraulic pump 34 is considered. The energy consumption can be minimized.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described.
The mold clamping apparatus 3 according to the third embodiment determines the combination of the swash plate angle θ and the rotation speed N that obtains the maximum efficiency Em by using the detected discharge hydraulic pressure ρd and the set flow rate (third set flow rate) Q3. Use. This is because the first embodiment and the second embodiment use the set oil pressure ρ1 and the set flow rate Q1, that is, only a predetermined value, whereas the discharge oil pressure uses the detected discharge oil pressure ρd. It is different in point.
As described above, the mold clamping device 3 has the same basic configuration as the mold clamping device 1 according to the first embodiment, but the combination of the swash plate angle θ and the rotational speed N that provides the highest efficiency Em. The procedure for determining is different. Hereinafter, a description will be given with reference to FIGS. 12 and 13.

  First, when the mold clamping force F is input as a control set value to the input unit 51 of the molding machine control unit 50 (S201 in FIG. 12), the control value generation unit 53 acquires the mold clamping force F and stores it in the storage unit 57. The discharge flow rate Q of the hydraulic pump 34 that drives the tie bar 17 at a predetermined speed value that does not depend on the predetermined molding conditions stored is specified (S203 in FIG. 12). The discharge flow rate Q specified here is expressed as a set flow rate Q3 in order to distinguish it from what is obtained later.

  When the control value generation unit 53 specifies the set flow rate Q3, the command output unit 55 acquires the control value from the control value generation unit 53, and sets the set angle θα and the set rotation of the hydraulic pump 34 corresponding to the set flow rate Q3. An operation command value is generated for the number Nα. The command output unit 55 outputs a command value CNα corresponding to the set rotational speed Nα to the servo control circuit 33 of the hydraulic pressure supply unit 30, and also outputs a command value Cθα corresponding to the set angle θα to the swash plate angle of the hydraulic pressure supply unit 30. Output to the control unit 37. The servo control circuit 33 controls the rotation speed N of the servo motor 32 based on the acquired command value CNα, and the swash plate angle control unit 37 operates the angle adjustment unit 36 based on the command value Cθα to thereby make hydraulic pressure By controlling the swash plate angle θ of the swash plate 35 of the pump 34, the servo motor 32 and the hydraulic pump 34 are driven under the third operating condition (S205 in FIG. 12).

  At this time, the pressure detector 41 of the hydraulic pressure supply unit 30 detects the discharge hydraulic pressure ρ (detected discharge hydraulic pressure ρd) of the hydraulic oil flowing inside the discharge pipe 39, and the control value generation unit 53 detects the detected discharge hydraulic pressure. ρd is acquired as the discharge hydraulic pressure ρ necessary for discharging the set flow rate Q3. The detected discharge hydraulic pressure ρd and the set flow rate Q3 are collated with the pump efficiency data stored in the storage unit 57, and the operating conditions (the set rotational speed N3 and the rotational speed N3) are obtained. The setting angle θ3) is selected (S207 in FIG. 12). Since this selection procedure is the same as that in the first embodiment, a description thereof is omitted here.

  Here, as the data for collating the detected discharge hydraulic pressure ρd and the set flow rate Q3, the pump unit efficiency data of the second embodiment can be used instead of the pump efficiency data.

If the set rotational speed N3 and the set angle θ3 at which the maximum efficiency Em3 is obtained are obtained, the command output unit 55 outputs the command value CN3 to the servo control circuit 33 in the same manner as in the first embodiment. The command value Cθ3 is output to the swash plate angle control unit 37. Hereinafter, similarly to the first embodiment, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em3 can be obtained (S209 in FIG. 12), and the clamping pressures of the fixed mold 14 and the movable mold 15 are It rises (S211 in FIG. 12).
The control value generation unit 53 continuously compares whether or not the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure (third set hydraulic pressure) ρ3 in the process of increasing the pressure of the mold (S213 in FIG. 12). If the detected discharge hydraulic pressure ρd does not reach the set hydraulic pressure ρ3, the control value generating unit 53 again checks the detected discharge hydraulic pressure ρd and the set flow rate Q3 with the pump efficiency data stored in the storage unit 57. Thus, the operating conditions (the set rotational speed N31 and the set angle θ31) at which the highest efficiency Em31 with the highest operating efficiency of the hydraulic pump 34 is obtained are selected. If the set rotational speed N31 and the set angle θ31 that can obtain the maximum efficiency Em31 are obtained, the command output unit 55 outputs the command value CN31 to the servo control circuit 33, and the command value Cθ31 is output to the swash plate angle control unit. To 37. Thereafter, similarly, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em 31 is obtained, and the clamping pressures of the fixed mold 14 and the movable mold 15 are increased.
As described above, the detected discharge hydraulic pressure ρd and the set flow rate (third set flow rate) Q3 are used to detect the operation by determining the combination of the swash plate angle θ and the rotational speed N that provides the maximum efficiency Em. Repeat until ρd reaches the set hydraulic pressure ρ3 (No in FIG. 12 S213).

  On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ3, the control value generating unit 53 performs a process of switching the set rotational speed N3 and the set angle θ3. That is, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ3, the control value generation unit 53 drives the tie bar 17 with a predetermined speed value that is stored in the storage unit 57 and does not depend on a predetermined molding condition. The set flow rate (fourth set flow rate) Q4 to be newly specified is specified, and the servo motor 32 and the hydraulic pump 34 are operated under the fourth operation condition of the set rotation speed Nβ and the set swash plate angle θβ corresponding to the set flow rate Q4. (FIG. 12 S213 Yes, FIG. 13 S215, S217). The set flow rate Q4 and the set flow rate Q3 have a relationship of set flow rate Q4 <set flow rate Q3.

  The control value generation unit 53 collates the detected discharge hydraulic pressure ρd and the set flow rate Q4, which have been continuously detected after the operation condition is switched, with the pump efficiency data stored in the storage unit 57, so that the hydraulic pump The operation condition that provides the highest efficiency Em4 with the highest operation efficiency 34 is selected (S219 in FIG. 13). Since this selection procedure is the same as that in the first embodiment, a description thereof is omitted here.

If the set rotational speed N4 and the set angle θ4 at which the maximum efficiency Em4 is obtained are obtained, the command output unit 55 outputs the command value CN4 to the servo control circuit 33 in the same manner as in the first embodiment. The command value Cθ4 is output to the swash plate angle control unit 37. Hereinafter, similarly to the first embodiment, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em4 is obtained (S221 in FIG. 13).
Since the subsequent steps until the boosting step is completed (FIG. 13, S223 to S231) are the same as those in the first embodiment, the following description is omitted.

  The third embodiment described above uses the detected discharge hydraulic pressure ρd when the hydraulic pump 34 is actually driven in addition to the first and second effects shown in the first embodiment. Since the conditions for obtaining the efficiency Em3 and Em4 are selected, it is possible to operate at the highest efficiency according to the reality and to minimize the energy consumption.

[Fourth Embodiment]
Next, a fourth embodiment according to the present invention will be described.
The mold clamping device 4 according to the fourth embodiment determines the combination of the swash plate angle θ and the rotation speed N at which the maximum efficiency Em is obtained, and the fifth set hydraulic pressure ρ5, the fifth set flow rate Q5, and the sixth set hydraulic pressure ρ6. And the sixth set flow rate Q6. In the first embodiment and the second embodiment, the set hydraulic pressures ρ1 and ρ2 are in a magnitude relationship of ρ1 <ρ2, and are obtained by calculation from the mold clamping force F set as a molding condition, and the set flow rates Q1 and Q2 are Q1>. It is in a magnitude relationship of Q2, and is a fixed value regardless of the molding conditions. On the other hand, the fourth embodiment is different from the first embodiment in that the set hydraulic pressures ρ1 and ρ2 and the set flow rates Q1 and Q2 are arbitrary values independent of each other. The fourth embodiment is also different from the first embodiment in that the set hydraulic pressures ρ1 and ρ2 and the set flow rates Q1 and Q2 are obtained by calculation from the operating speed of the tie bar 17 set as the molding conditions. The set flow rates Q1, Q2 correspond to the discharge flow rates Qnc, Q1c, Q2c in the present invention. Further, since the configuration of the mold clamping device 4 is substantially the same as that of the mold clamping device 1, description of the configuration of the mold clamping device 4 is omitted. However, the mold clamping device 4 includes a position detector 58 for the movable die plate 13 as shown in FIG.

[Procedure for pressure control and flow control]
The procedure for determining the combination of the swash plate angle θ and the rotational speed N that gives the maximum efficiency Em using the pump efficiency data will be further described with reference to FIG. This procedure is a so-called injection compression in which the movable die plate 13 is clamped by controlling a predetermined speed and a predetermined mold clamping force in a plurality of stages from a position where the movable mold 15 and the fixed mold 14 are separated by a predetermined distance. This relates to the process, and is performed while detecting the hydraulic pressure ρ, the discharge flow rate Q, and the position of the movable die plate 13 or the movable mold 15 from the hydraulic pump 34. In this embodiment, the moving die plate 13 will be described by taking two steps as an example for the sake of simplicity of the number of steps for switching between a predetermined speed and a predetermined mold clamping force.

  First, the first mold clamping force F1, the first mold clamping speed V1, the second mold clamping force F2, the second mold clamping speed V2, and the mold clamping force are switched as control set values to the input unit 51 of the molding machine control unit 50. The setting switching position Ls and the mold clamping completion position Lc are input (S301 in FIG. 14). The setting switching position Ls corresponds to the operation switching position of the present invention, and the mold clamping completion position Lc corresponds to the operation completion position of the present invention. Then, the control value generation unit 53 acquires the first mold clamping force F1 and the second mold clamping force F2, and refers to the mold clamping force / discharge hydraulic pressure conversion data stored in the storage unit 57 to A first set hydraulic pressure ρ1p of the hydraulic pump 34 necessary for generating the first mold clamping force F1 by operating the tie bar 17 at the mold clamping speed V1 is obtained. At the same time, the first set flow rate Q1p required to operate the tie bar 17 at the first mold clamping speed V1 is obtained with reference to the speed-discharge flow rate conversion data (S303 in FIG. 14). Therefore, the first set oil pressure ρ1p and the first set flow rate Q1p correspond to the first set oil pressure ρ1c and the first set flow rate Q1c in the present invention, respectively.

  Next, when the control value generation unit 53 obtains the first set hydraulic pressure ρ1p and the first set flow rate Q1p, the operation efficiency of the hydraulic pump 34 is the highest with reference to the pump efficiency data stored in the storage unit 57. The operating condition to be increased is selected (FIG. 14, S305). This selection is performed in the same manner as in the first embodiment and the second embodiment, and the set rotational speed N1 and the set angle θ1 at which the maximum efficiency Em1 is obtained are selected, and the servo motor 32 and the hydraulic pump 34 are based on this set condition. Are operated (FIG. 14, S307). Thereby, the moving die plate 13 is moved toward the fixed die plate 12 (S309 in FIG. 14).

  While the moving die plate 13 is moving toward the fixed die plate 12, the position detector 58 of the moving die plate 13 detects the position of the moving die plate 13, and the detected value is referred to as a detection position L1. To do. The detection position L1 is sent from the position detector 58 to the control value generation unit 53 of the molding machine control unit 50, and the control value generation unit 53 that has acquired the detection position L1 determines whether or not the detection position L1 reaches the setting switching position Ls. Are continuously compared (S311 in FIG. 14). Since the control value generation unit 53 does not issue a switching instruction to the command output unit 55 unless the detection position L1 reaches the setting switching position Ls, the servo motor 32 and the hydraulic pump 34 continue to operate under the previous conditions. (FIG. 14 S311 No). The position detector 58 may use a position encoder of the ball screw shaft 25.

  On the other hand, when the detection position L1 reaches the setting switching position Ls (S311 Yes in FIG. 14), the control value generation unit 53 performs a process of switching the setting angle θ1 and the setting rotational speed N1. That is, when the detection position L1 reaches the setting switching position Ls, the control value generation unit 53 refers to the mold clamping force / discharge hydraulic pressure conversion data stored in the storage unit 57 and obtains the set hydraulic pressure ρ2p. At the same time, a set flow rate Q2p necessary for operating the tie bar 17 at the second mold clamping speed V2 is newly specified with reference to the speed-discharge flow rate conversion data (S313 in FIG. 14). Accordingly, the set oil pressure ρ2p and the set flow rate Q2p correspond to the second set oil pressure ρ2c and the second set flow rate Q2c in the present invention, respectively.

  When the control value generating unit 53 obtains the set hydraulic pressure ρ2p and the set flow rate Q2p, the control value generating unit 53 refers to the pump efficiency data stored in the storage unit 57 and selects the operating condition in which the operating efficiency of the hydraulic pump 34 is the highest. (FIG. 14, S315). This selection is performed in the same manner as the procedure for selecting the set angle θ1 and the set rotation speed N1. The selected swash plate angle θ and rotation speed N are expressed as a setting angle θ2 and a setting rotation speed N2.

  When the set rotational speed N2 and the set angle θ2 at which the maximum efficiency Em2 is obtained are selected, the servo motor 32 and the hydraulic pump 34 are operated under the conditions (S317 in FIG. 14). As a result, the movable die plate 13 is continuously moved toward the fixed die plate 12 by moving the tie bar 17 after being temporarily stopped at the setting switching position Ls or without being temporarily stopped. 14 S319).

  The control value generation unit 53 continuously acquires the detection position L1 and continuously compares whether or not the detection position L1 reaches the mold clamping completion position Lc (S321 in FIG. 14). If the detection position L1 does not reach the mold clamping completion position Lc, the servo motor 32 and the hydraulic pump 34 continue to operate under the previous conditions (No in S321 in FIG. 14).

On the other hand, when the detection position L1 reaches the mold clamping completion position Lc, the control value generation unit 53 sends a command to the command output unit 55 to stop the operation of the servo motor 32, and the command output unit 55 In response, the servo control circuit 33 is instructed to stop the servo motor 32. As a result, the operation of the servo motor 32 is stopped, and the compression process is terminated (S323 in FIG. 14).
Thereafter, the mold clamping state is maintained for a predetermined time and the resin in the mold is cooled and solidified, and then the movable mold 15 and the movable die plate 13 are opened to take out the molded product.

In the fourth embodiment described above, the moving die plate 13 is switched at a predetermined speed and a predetermined mold clamping force in a plurality of stages depending on the position of the moving die plate 13. You may carry out by the time-up of the timer which starts from the start or the switching position of several steps.
Moreover, in this embodiment, although the example which applied this invention to switching of the arbitrary moving speeds and moving pressures of the movement die plate 13 in the injection compression process of the mold clamping apparatus 1 was shown, in the injection compression process of a mold clamping apparatus. Instead, it may be applied to switching control of an arbitrary moving speed and moving pressure in the injection filling process of the injection apparatus.
Moreover, you may perform the pressure | voltage rise process of 1st Embodiment or 2nd Embodiment after the injection compression process of this embodiment.

  The fourth embodiment described above has the first effect and the second effect shown in the first embodiment, and the set hydraulic pressures ρ1, ρ2 and the discharge flow rates Q1, Q2 calculated from the set molding conditions. Regardless of the magnitude relationship, the hydraulic pump 34 and the servo motor 32 can be operated with the highest efficiency, and the energy consumption can be minimized.

The preferred embodiments of the present invention have been described above. However, the configurations described in the above embodiments can be selected or changed to other configurations as appropriate without departing from the gist of the present invention.
For example, in the first to third embodiments, the set operation condition is collated with the pump efficiency data after the boosting process is started. However, according to the present invention, the preset operating conditions and the pump efficiency data are collated in advance to identify the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that can obtain the maximum efficiency, and this is the data. You can also keep it as In this case, the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that can obtain the maximum efficiency are specified by collating the set operating conditions with the data after starting the boosting step.
In the first to fourth embodiments, the set flow rate Q and the set hydraulic pressure ρ are shown in two stages, but may be performed by switching between two or more stages of three stages, four stages, ... n stages. .

  Further, in the first to fourth embodiments, the example using the pump efficiency data of the swash plate angle θ and the swash plate angle θ of the hydraulic pump 34 stored in the storage unit 57 is shown. However, in the present invention, the pump efficiency data at the swash plate angle not stored in the storage unit 57 is interpolated based on the respective pump efficiency data of the swash plate angle θ and the swash plate angle θ stored in the storage unit 57. It can ask for. Then, the pump efficiency data obtained by the interpolation operation is compared with the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate, and the swash plate angle θ of the hydraulic pump and the number of rotations of the electric motor can be obtained with the highest efficiency. N may be selected and the hydraulic pump 34 and the servo motor 32 may be operated. In this case, even if the number of pump efficiency data obtained by experiment or simulation such as numerical analysis for the hydraulic pump 34 or the servo motor 32 is small, pump operation under a wide range of conditions is insufficient. Therefore, the hydraulic pump 34 or the servo motor 32 can be operated at the highest efficiency by interpolating and creating appropriate pump efficiency data.

1, 2, 3 Mold clamping device 11 Base frame 12 Fixed die plate 13 Moving die plate 14 Fixed mold 15 Movable mold 16 Ram 17 Tie bar 18 Clamping cylinder 181 Mold clamping side chamber 182 Mold opening side chamber 19 Injection cylinder 20, 21 Bearing Box 22 Servo motors 23 and 24 Power transmission gear 25 Ball screw shaft 26 Guide rail 27 Linear bearing 28 Slide base 29 Half nut 30 Hydraulic supply part 31 Hydraulic source 32 Servo motor 33 Servo control circuit 34 Hydraulic pump 35 Swash plate 36 Angle adjustment part 37 Swash plate angle control unit 39 Discharge piping 40 Hydraulic oil piping 41 Pressure detector 45 Angle detector 50 Molding machine control unit 51 Input unit 53 Control value generation unit 55 Command output unit 57 Storage unit 58 Position detector

Claims (16)

A hydraulic actuator;
An injection molding machine that operates the hydraulic actuator, comprising a hydraulic supply unit that operates by supplying hydraulic oil to the hydraulic actuator;
The hydraulic supply section
A variable displacement hydraulic pump by changing the swash plate angle θ,
An electric motor that drives a hydraulic pump;
A control unit that variably controls the rotational speed N of the electric motor,
The control unit
When the operation setting condition of the hydraulic actuator is set, a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate corresponding to the operation setting condition are associated with the operation condition of the hydraulic pump and the operation efficiency of the hydraulic pump. The pump efficiency data is collated to identify the swash plate angle θ of the hydraulic pump and the rotational speed N of the electric motor that can obtain the maximum efficiency when operating at a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. In addition, the operation of the hydraulic pump and the electric motor is controlled by the specified swash plate angle θ of the hydraulic pump and the rotational speed N of the electric motor.
An injection molding machine characterized by that. Pump efficiency data is
Operation efficiency data as a single hydraulic pump, or
Correction efficiency data that is obtained by adding the efficiency data of the electric motor to the data of the operation efficiency of the hydraulic pump alone.
The injection molding machine according to claim 1. The predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate are
It consists of a preset discharge hydraulic pressure ρ and a preset discharge flow rate Qn.
The injection molding machine according to claim 1 or 2. The discharge hydraulic pressure ρ set in advance is the discharge hydraulic pressure ρc calculated from the operation setting conditions,
The preset discharge flow rate Qn is a discharge flow rate Qns that does not depend on the operation setting conditions.
The injection molding machine according to claim 3. The discharge hydraulic pressure ρ set in advance is the discharge hydraulic pressure ρc calculated from the operation setting conditions,
The preset discharge flow rate Qn is the discharge flow rate Qnc calculated from the operation setting conditions.
The injection molding machine according to claim 3. The predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate are
It consists of a detected discharge hydraulic pressure ρd detected and a preset discharge flow rate Qn.
The injection molding machine according to claim 1 or 2. The preset discharge flow rate Qn is a discharge flow rate Qns that does not depend on the operation setting conditions.
The injection molding machine according to claim 6. 7. The injection molding machine according to claim 6, wherein the preset discharge flow rate Qn is a discharge flow rate Qnc calculated from the operation setting conditions. A storage unit for storing pump efficiency data for each of a plurality of different swash plate angles θ;
The control unit
For each pump efficiency data of a plurality of swash plate angles θ, a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate are collated to obtain the maximum efficiency of the swash plate angle θ of the hydraulic pump and the electric motor Specify the rotational speed N,
The injection molding machine according to any one of claims 1 to 8. The control unit
The pump efficiency data at the swash plate angle not stored in the storage unit is obtained by interpolation based on the pump efficiency data of the swash plate angle θ and swash plate angle θ stored in the storage unit,
The pump efficiency data obtained by the interpolation operation is compared with a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate, and the swash plate angle θ of the hydraulic pump and the rotational speed N of the electric motor that can obtain the highest efficiency are obtained. Identify
The injection molding machine according to claim 9. The control unit
As a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate,
A first operating condition comprising a first set hydraulic pressure ρ1 set in advance and a first set flow rate Q1 set in advance;
A second operating condition consisting of a preset second set hydraulic pressure ρ2 (where ρ2> ρ1) and a preset second set flow rate Q2 (where Q2 <Q1),
The control unit
Until the detected discharge hydraulic pressure ρd reaches the first set hydraulic pressure ρ1, the swash plate angle θ1 of the hydraulic pump and the rotational speed N1 of the electric motor are specified by collating the first operating condition with the pump efficiency data. Control the operation of the hydraulic pump and the electric motor,
Until the detected discharge hydraulic pressure ρd exceeds the first set hydraulic pressure ρ1 and reaches the second set hydraulic pressure ρ2, the second operating condition and the pump efficiency data are collated, the swash plate angle θ2 of the hydraulic pump, and the rotation of the electric motor Specify the number N2, and control the operation of the hydraulic pump and the electric motor.
The injection molding machine according to any one of claims 3, 4, 5, 9, and 10. The control unit
As a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate,
A first operating condition comprising a first set hydraulic pressure ρ1 set in advance and a first set flow rate Q1 set in advance;
A second operating condition consisting of a preset second set hydraulic pressure ρ2 (where ρ2> ρ1) and a preset second set flow rate Q2 (where Q2 <Q1),
The control unit
Until the detected discharge hydraulic pressure ρd reaches the first set hydraulic pressure ρ1, the detected discharge hydraulic pressure ρd, the first set flow rate Q1, and pump efficiency data are collated, and the swash plate angle θ1 of the hydraulic pump, and Identifying the rotational speed N1 of the electric motor, and controlling the operation of the hydraulic pump and the electric motor,
Until the detected discharge oil pressure ρd exceeds the first set oil pressure ρ1 and reaches the second set oil pressure ρ2, the detected discharge oil pressure ρd, the second set flow rate Q2, and the pump efficiency data are collated to check the inclination of the hydraulic pump. Specify the plate angle θ2 and the rotation speed N2 of the electric motor, and control the operation of the hydraulic pump and the electric motor.
The injection molding machine according to any one of claims 6 to 10. The first set hydraulic pressure ρ1 set in advance is the first set hydraulic pressure ρ1c calculated from the operation setting conditions,
The first set flow rate Q1 set in advance is the first set flow rate Q1s not depending on the operation setting condition,
The preset second set oil pressure ρ2 is equal to or higher than the first set oil pressure ρ1, and is the second set oil pressure ρ2c calculated from the operation setting conditions.
The preset second set flow rate Q2 is equal to or less than the first set flow rate Q1, and is the second set flow rate Q2s not depending on the operation setting conditions.
The injection molding machine according to claim 11 or 12. The first set hydraulic pressure ρ1 set in advance is the first set hydraulic pressure ρ1c calculated from the operation setting conditions,
The preset first set flow rate Q1 is the first set flow rate Q1c calculated from the operation setting conditions,
The preset second set oil pressure ρ2 is the second set oil pressure ρ2c calculated from the operation setting conditions,
The preset second set flow rate Q2 is the second set flow rate Q2c calculated from the operation setting conditions.
The injection molding machine according to claim 11 or 12. The control unit
As a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate,
A first operating condition comprising a first set hydraulic pressure ρ1p determined by calculation and a first set flow rate Q1p determined by calculation;
A second operating oil pressure ρ2p obtained by computation and a second operating condition comprising a second set flow rate Q2p obtained by computation,
The control unit
Until the detected position L1 of the movement target of the hydraulic actuator reaches the operation switching position Ls, the swash plate angle θ1 of the hydraulic pump and the rotation speed of the electric motor are compared by comparing the first operation condition with the pump efficiency data. N1 is specified, and the operation of the hydraulic pump and the electric motor is controlled.
Until the detected position L1 of the movement target reaches the operation completion position Lc, the second operating condition and the pump efficiency data are collated to identify the swash plate angle θ2 of the hydraulic pump and the rotational speed N2 of the electric motor And control the operation of the hydraulic pump and the electric motor,
The injection molding machine according to claim 1 or 2. The hydraulic pump generates clamping force on the moving mold via the tie bar.
Clamping force-discharge hydraulic pressure conversion data, which is data in which the set mold clamping force and the discharge hydraulic pressure of the hydraulic pump necessary to generate the mold clamping force are associated with each other, and the predetermined operation set A storage unit for storing speed-discharge flow rate conversion data, which is data in which the speed and the discharge flow rate of the hydraulic pump necessary to operate the tie bar at the moving speed are stored;
The control unit
When the first mold clamping force F1 is set, the first set hydraulic pressure ρ1p is obtained with reference to the mold clamping force-discharge hydraulic pressure conversion data,
When the first mold clamping speed V1 is set, the first set flow rate Q1p is obtained with reference to the speed-discharge flow rate conversion data,
When the second mold clamping force F2 is set, the second set hydraulic pressure ρ2p is obtained with reference to the mold clamping force-discharge hydraulic pressure conversion data,
When the second mold clamping speed V2 is set, the second set flow rate Q2p is obtained with reference to the speed-discharge flow rate conversion data.
The injection molding machine according to claim 15.

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