JP6730812B2 - Injection molding machine - Google Patents

Description

The present invention relates to an injection molding machine that variably controls a hydraulic pump to control a predetermined operation process in a molding cycle with high efficiency.

Injection molding is a mold clamping process of closing a pair of molds to perform mold clamping, an injection process of injecting a molten material into a cavity in the mold, and a pressure holding process of continuously applying pressure to the injected material for a predetermined period. It is carried out by carrying out a mold opening step of opening the mold after the injected material is solidified, and a protruding step of protruding a molded product fixed to the mold. An injection molding machine for performing such injection molding includes a plurality of hydraulic actuators for carrying out each process, and a hydraulic pressure supply device for supplying hydraulic oil to these hydraulic actuators. The pressure control or the flow rate control is executed by the hydraulic pressure supply device to generate a driving force by these hydraulic actuators to perform each step.

Patent Literature 1 variably controls the rotational speed of a drive motor that drives a hydraulic pump to control each operation process in a molding cycle, and a fixed discharge flow rate Qm of a large flow rate and a small flow rate smaller than the large flow rate. The hydraulic pump capable of setting the fixed discharge flow rate Qs is used, and the limit condition by the threshold value 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 large discharge flow rate Qm to control the operation process, the load state of a drive motor is monitored, and the load state is a limit condition. When it reaches, the discharge flow rate Qs is switched to a fixed small flow rate.
According to the control method of Patent Document 1, it is possible to set the optimum threshold value (limit condition) for the drive motor while avoiding the overload of the drive motor. Therefore, it is possible to avoid an inconvenience that an unnecessary load is unnecessarily applied to the drive motor, and thus to the hydraulic pump, resulting in a large amount of energy consumption, and it is possible to set an optimum operating state.

JP, 2009-285972, A

Japanese Patent Application Laid-Open No. 2004-242242 sets a limit condition for switching the fixed discharge amount of the pump in consideration of a predetermined margin and the like before the load pressure and the load time when the servo motor stops due to overload. Therefore, even if an excessive load is generated due to some abnormality or the time required for a predetermined operation process is lengthened, the servo motor may stop (trip) due to overload, and unnecessary load may be applied unnecessarily. It is possible to avoid the problem that the energy consumption increases. However, in Patent Document 1, the fixed discharge flow rate Qs of a small flow rate is set to a discharge quantity that does not trip even under a high load and for a long time, and the fixed discharge flow rate Qm of a large flow rate is fixed to a small flow rate. It is only necessary to set the discharge amount to about twice the flow rate Qs. By the way, normally, the energy consumption efficiency of the pump changes with the operating conditions, specifically, the discharge flow rate and the discharge pressure. Therefore, in Patent Document 1, particularly at a fixed discharge flow rate Qm of a large flow rate, the pump may be operated under operating conditions of low efficiency in terms of operating efficiency of the pump, resulting in wasting energy consumption.
Therefore, an object of the present invention is to provide a mold clamping device of an injection molding machine that can always drive a hydraulic pump with high efficiency.

The present invention relates to a mold clamping device that includes a hydraulic actuator and a hydraulic supply unit that supplies hydraulic oil to the hydraulic actuator to operate 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 that changes the swash plate angle θ, an electric motor that drives the hydraulic pump, and a control unit that variably controls the rotation 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 operating oil pressure and the predetermined operating oil flow rate corresponding to the operation setting condition to the operating condition of the hydraulic pump and the operating condition of the hydraulic pump. The efficiency is collated with the pump efficiency data in which the efficiency is associated, and the swash plate angle θ of the hydraulic pump and the electric motor of the electric motor that achieve the highest efficiency when operating at a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. The rotational 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 specified rotational speed N of the electric motor.

In the injection molding machine of the present invention, the pump efficiency data is the operation efficiency data of the hydraulic pump alone, or the correction efficiency data obtained by adding the efficiency data of the electric motor to the operation 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 may 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 set as the discharge hydraulic pressure ρc calculated from the operation setting condition, and the preset discharge flow rate Qn may be set as the discharge flow amount 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 the detected detected discharge hydraulic pressure ρd and the preset discharge flow rate Qn. In this case, the preset discharge flow rate Qn may be the discharge flow rate Qns that does not depend on the operation setting conditions, or may be the discharge flow rate Qnc calculated from the operation setting conditions.

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

In the injection molding machine of the present invention, the control unit controls the pump efficiency data for the swash plate angles not stored in the storage unit to be the pump efficiency data for the swash plate angle θ and the swash plate angle θ stored in the storage unit. Based on the interpolation calculation, the pump efficiency data obtained by the interpolation calculation is collated with a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate, and the swash plate angle θ of the hydraulic pump that obtains the maximum efficiency is obtained. Also, the rotation speed N of the electric motor can be specified.

In the injection molding machine of the present invention, the control unit includes a preset first hydraulic pressure ρ1 and a preset first preset flow rate Q1 as a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. A first operating condition and 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). Until the detected discharge oil pressure ρd reaches the first set oil pressure ρ1, the swash plate angle θ1 of the hydraulic pump and the rotation speed N1 of the electric motor are specified by collating the first operating condition and the pump efficiency data. , The operation of the hydraulic pump and the electric motor is controlled, and the second operating condition and the pump efficiency data are collated until the detected discharge hydraulic pressure ρd exceeds the first set hydraulic pressure ρ1 and reaches the second set hydraulic pressure ρ2. It is possible to control the operation of the hydraulic pump and the electric motor by specifying the swash plate angle θ2 of the pump and the rotation speed N2 of the electric motor.

In the injection molding machine of the present invention, the control unit includes a preset first hydraulic pressure ρ1 and a preset first preset flow rate Q1 as a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate. A first operating condition and 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). Until the detected discharge hydraulic pressure ρd reaches the first set hydraulic pressure ρ1, the detected detected discharge hydraulic pressure ρd, the first set flow rate Q1, and the pump efficiency data are collated to check the swash plate angle θ1 of the hydraulic pump, and Until the detected discharge hydraulic pressure ρd exceeds the first set hydraulic pressure ρ1 and reaches the preset second set hydraulic pressure ρ2 by controlling the operation of the hydraulic pump and the electric motor by specifying the rotation speed N1 of the electric motor. , The detected discharge hydraulic pressure ρd, the second set flow rate Q2, and the pump efficiency data are collated to specify the swash plate angle θ2 of the hydraulic pump and the rotation speed N2 of the electric motor to determine the hydraulic pump and the electric motor. It is also possible to control the operation of the motor.

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

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

In the injection molding machine of the present invention, the control unit controls the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate to be the first set hydraulic pressure ρ1p calculated and the first set flow rate Q1p calculated. And a second operating condition consisting of the second set hydraulic pressure ρ2p calculated by the calculation and the second set flow rate Q2p calculated by the calculation.
Then, the control unit collates the first operating 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 second operating condition and the pump are controlled until the rotational speed N1 of the electric motor is specified, the operation of the hydraulic pump and the electric motor is controlled, and the detected position L1 of the movement target reaches the operation completion position Lc. The swash plate angle θ2 of the hydraulic pump and the rotation speed N2 of the electric motor can be specified by collating with the efficiency data to control the operation of the hydraulic pump and the electric motor.

In this injection molding machine, when the hydraulic pump is to generate a mold clamping force on the movable mold through the tie bar, the set mold clamping force and the hydraulic pressure required to generate the mold clamping force are set. Clamping force-discharge hydraulic pressure conversion data, which is data in which the discharge hydraulic pressure of the pump is associated with each other, the predetermined operating speed that is set, and the discharge flow rate of the hydraulic pump that is required to operate the tie bar at the moving speed. It is possible to provide a storage unit that stores speed-discharge flow rate conversion data that is data associated with and. Then, when the first mold clamping force F1 is set, the control unit refers to the mold clamping force-discharge hydraulic pressure conversion data to obtain the first set hydraulic pressure ρ1p, and when the first mold clamping speed V1 is set, When the second set mold clamping force F2 is set by referring to the speed-discharge flow rate conversion data and the second mold clamping force F2 is set, the second set hydraulic pressure ρ2p is calculated by referring to the mold clamping force-discharge hydraulic pressure converted data. When the second mold clamping speed V2 is set, the second set flow rate Q2p can be calculated by referring to the speed-discharge flow rate conversion data.

According to the injection molding machine of the present invention, the servomotor and the hydraulic pump can be operated under the operating conditions of the highest efficiency according to the set operation setting conditions of the hydraulic actuator, so that the hydraulic pump can always be operated with high efficiency. Moreover, according to the injection molding machine of the present invention, since the condition of this highly efficient operation is set based on the pump efficiency data created in advance for the hydraulic pump, the condition of the highly efficient operation is set accurately. 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 showing an example of pump efficiency data (swash plate angle thetax) used in a 1st embodiment. It is a figure showing an example of pump efficiency data (swash plate angle thetay) used in a 1st embodiment. It is a figure which shows an example of the pump efficiency data (swash plate angle (theta)z) used in 1st Embodiment. In the first embodiment, it is a flow chart showing a procedure of a boosting process performed based on a combination of a swash plate angle θ and a rotation speed N at which the maximum efficiency Em is obtained using pump efficiency data. In 1st Embodiment, it is a figure explaining the procedure which specifies the maximum efficiency Em1 in setting hydraulic pressure (rho)1 and setting rotation speed N1. In 1st Embodiment, it is a figure explaining the procedure which specifies the maximum efficiency Em2 in setting hydraulic 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 showing that pump efficiency data and motor efficiency data used in a 2nd embodiment are added up. In 3rd Embodiment, it is a part of flowchart which shows the procedure of the pressurization process performed based on the combination of the swash plate angle (theta) and rotation speed N which can obtain the maximum efficiency Em using pump efficiency data. In 3rd Embodiment, it is another part of the flowchart which shows the procedure of the pressurization process performed based on the combination of the swash plate angle (theta) and rotation speed N which can obtain the maximum efficiency Em using pump efficiency data. In 4th Embodiment, it is a flowchart which shows the procedure of the pressure|voltage rise process performed based on the combination of the swash plate angle (theta) and rotation speed N which can obtain the maximum efficiency Em using pump efficiency data.

Hereinafter, with reference to the accompanying drawings, an injection molding machine of the present invention will be described for a preferred embodiment of the present invention by taking a mold clamping device 1 as an example for simplicity.
[First Embodiment]
The mold clamping device 1 of the present embodiment was obtained in advance by an experiment or a simulation such as numerical analysis with respect to the hydraulic pump when the servomotor and the hydraulic pump were operated under high-efficiency operating conditions in the step-up process. By using the pump efficiency data, highly efficient operation conditions can be set accurately. Hereinafter, the configuration of the mold clamping device 1 and the procedure of the pressurizing process in the mold clamping device 1 will be sequentially described.

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

In the mold clamping device 1, as shown in FIG. 1, a fixed die plate 12 holding a fixed mold 14 is fixedly provided on the upper surface of one end side of a base frame 11.
On the upper surface of 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 back and forth so as to face 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. A slide plate may be used instead of the linear bearing 27 to support the movable die plate 13 via the slide base 28.
The fixed die plate 12 is provided with four hydraulic mold clamping cylinders 18 each having a small stroke and a large cross-sectional area at its four corners. 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 surface of each of the rams 16 sliding in the mold clamping cylinder 18, and the tie bars 17 are opened to the movable die plate 13 when the opposing movable die plate 13 approaches for closing the mold. It penetrates through the four inserted holes.
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 movable die plate 13, and is rotatably supported by the bearing box 20 held by the fixed die plate 12 and the bearing box 21 held by the base frame 11 while restraining the axial direction. The ball screw shaft 25 driven by the servomotor 22 via the power transmission gears 23 and 24 constitutes a moving means of the moving die plate 13. The rotation speed and rotation speed of the ball screw shaft 25 are controlled by a controller (not shown) via the servo motor 22.
The other end of each tie bar 17 is formed with a plurality of ring-shaped parallel grooves (or spiral screw grooves) having 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 has 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 movable die plate 13 is moved by the rotation of the ball screw shaft 25 driven by 22. The movable die plate 13 stops when the mutually facing surfaces of the fixed mold 14 and the movable mold 15 come into contact with each other.

At the stop position of the moving die plate 13, the half nut 29 is operated 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. And combine. After that, the mold clamping side chamber 181 of the mold clamping cylinder 18 is pressurized to clamp the mold. After the mold is clamped in this manner, a molten resin is injected from the injection cylinder 19 into the 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 for supplying hydraulic fluid, a hydraulic fluid pipe 40 connected to the hydraulic pressure source 31, and a pressure detector 41 provided in the hydraulic fluid pipe 40. ..
The molding machine control unit 50 also serves as a control unit that determines whether the hydraulic pressure source 31 in the hydraulic pressure supply unit 30 is operating or stopped, and the flow rate and pressure during operation.

The hydraulic power source 31 includes a servo motor 32, a servo control circuit 33 capable of variably controlling the number of revolutions of the servo motor 32, a hydraulic pump 34 that is driven by rotational driving of the servo motor 32 to discharge hydraulic oil, and a hydraulic pump 34. It has a discharge pipe 39 through which the hydraulic oil discharged from the tank flows, and a swash plate angle controller 37 for controlling 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 a 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 command value of the rotation speed N input from the molding machine control unit 50 and outputs it 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 obtains the rotation speed N while performing feedback correction based on the rotation angle. Then, 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 motor is arbitrary, and an AC servo motor, a DC servo motor, a stepping motor, etc. can be applied. .. As for 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 sticking type (SPM) motor or an internal magnet embedded type (IPM) motor.

The hydraulic pump 34 in the present embodiment is a variable displacement type pump, which is rotatable by a servomotor 32 around the central axis at a constant number of revolutions, and a swash plate 35 capable of changing the inclination angle with respect to the central axis. 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 included.
The swash plate angle control unit 37 operates the angle adjustment unit 36 to adjust the angle of the swash plate 35 based on the swash plate angle θ command input from the molding machine control unit 50. The tilt angle of the swash plate 35 is feedback-controlled based on the detection result.
Although not shown, the angle adjusting unit 36 includes, for example, a spring that biases the swash plate 35, a hydraulic angle adjusting actuator that changes the tilt angle of the swash plate 35 against the bias of the spring, and a hydraulic pressure. And an electromagnetic directional control 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 a control set value and a control value that generates control values for the servo motor 32 and the hydraulic pump 34. The generation unit 53, the command output unit 55 that acquires the control values for the servo motor 32 and the hydraulic pump 34 from the control value generation unit 53 and generates the control command, and that outputs the generated control command, and the 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 regarding the hydraulic pump 34.
The pump efficiency data is obtained by operating the tie bar 17 by applying a predetermined speed and a predetermined hydraulic pressure to obtain a set mold clamping pressure when performing the mold clamping operation of the movable mold 15 and the fixed mold 14. It is used to determine the combination of the swash plate angle θ and the rotation speed N that achieves the maximum efficiency Em from among a plurality of combinations of the swash plate angle θ and the rotation speed N of the hydraulic pump 34 required for the above.
The pump efficiency data is associated with the operating conditions of the hydraulic pump 34 and the operating efficiency of the hydraulic pump 34, and is acquired in advance for the hydraulic pump 34. For example, as shown in FIGS. The driving condition and the driving efficiency are associated with each other at the swash plate angles θx, θy, and θz. FIG. 4 is a correlation diagram of the operating conditions and the operating efficiency at the swash plate angle θx, FIG. 5 is a correlation diagram of the operating conditions and the operating efficiency at the swash plate angle θy, and FIG. 6 is a correlation diagram of the operating conditions and the operating efficiency at the swash plate angle θz. Are shown respectively. The first horizontal axis on the lower side of each drawing shows the discharge flow rate Q of the hydraulic oil discharged from the hydraulic pump 34, and the first vertical axis on the left side of the drawing shows the discharge hydraulic pressure ρ of the oil discharged from the hydraulic pump 34. It is a map-like data in which the efficiency of the hydraulic pump 34 is indicated by contour lines on the two-dimensional coordinates. The second horizontal axis of the two-dimensional coordinates represents the rotation speed N of the hydraulic pump 34, and the second vertical axis represents 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, and in the present embodiment, three different swash plate angles θx, θy, and θz are shown as shown in FIGS. 4 to 6. However, this is only an example, and the swash plate angles can be four or more.
Further, in the present embodiment, the map data that is visually easy to understand is taken as an example as the pump efficiency data, but in the present invention, the data format is arbitrary as long as the same function can be achieved, and the data in the table format is used. Alternatively, the data may be a function formula.

When the discharge flow rate Q and the discharge oil 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 one of the swash plate angles θx, θy, and θz from which the maximum efficiency Em is obtained and the swash plate angle θ are obtained. The rotation 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 rotation speed N. Note that the higher the efficiency E, the less energy is consumed when operating the hydraulic pump 34.

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

[Procedure for boosting process]
A procedure for determining the combination of the swash plate angle θ and the rotation speed N using the pump efficiency data to obtain the maximum efficiency Em will be further described with reference to FIGS. 7 to 9. This procedure relates to a so-called step-up process of 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 mold clamping cylinder 18, and after reaching the set hydraulic pressure ρ1, the discharge flow rate Q is reduced to clamp the mold clamping cylinder 18. Is assumed to be large.

First, when the mold clamping force F as the operation setting condition is input as the control set value to the input unit 51 of the molding machine control unit 50 (S101 in FIG. 7), the control value generation unit 53 acquires the mold clamping force F and , The discharge hydraulic pressure ρ of the hydraulic pump 34 required to generate the mold clamping force F is obtained with reference 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 required to operate 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 operating condition) obtained here are referred to 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 calculated 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. Therefore, 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 oil pressure ρ1 is the above-mentioned threshold value, and a value lower than the mold clamping force F is adopted.

The control value generation unit 53 refers to the pump efficiency data stored in the storage unit 57 when the set hydraulic pressure ρ1 and the set flow rate Q1 (first set hydraulic pressure, first set flow rate, first operating condition) are obtained. Then, 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 performed by specifying any one of the swash plate angles θx, θy, and θz at which the maximum efficiency Em is obtained, and the number of revolutions N at the swash plate angle θ. The swash plate angle θ and the rotation speed N selected here are referred to as a set angle θ1 and a set rotation speed N1 in order to distinguish them from those to be obtained later.

For example, in FIGS. 8A, 8B, and 8C that show the correlation between the operating condition and the operating efficiency at each of the swash plate angles θx, θy, and θz, the hydraulic pump 34 at the set hydraulic pressure ρ1 and the set rotational speed N1 will be described. Since the swash plate angles θx, θy, and θz are 88%, 89%, and 87%, respectively, the maximum efficiency Em1 is 89%, and the rotation speed N and the swash plate angle at which the maximum efficiency Em1 is obtained are the operating efficiencies. The combination of θ is the set rotation speed N1 and the swash plate angle θy. This swash plate angle θy is set as the set angle θ1.

When the set rotation speed N1 and the set angle θ1 with which the highest efficiency Em1 is obtained are obtained in this way, the command output unit 55 acquires the control value from the control value generation unit 53, and sets the set rotation 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 rotation speed N1 to the servo control circuit 33 of the hydraulic pressure supply unit 30, and also outputs a command value Cθ1 corresponding to the set angle θ1 of 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 adjusting 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 mold clamping pressure of the fixed mold 14 and the movable mold 15 increases (S109 in FIG. 7). ).
The pressure detector 41 of the hydraulic pressure supply unit 30 detects the discharge hydraulic pressure ρ of the hydraulic oil flowing inside the hydraulic oil pipe 40 during the process of increasing the pressure of the mold, and the detected value is referred to 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, and 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. Whether or not is continuously compared (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 ( Figure 7 S111 No).

On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ1, the control value generation unit 53 switches 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 required to operate the tie bar 17 at a predetermined speed is newly identified by referring to the speed-discharge flow rate conversion data (S115 in FIG. 7). The set hydraulic 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 calculated 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. Therefore, 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.

After obtaining the set hydraulic pressure ρ2 and the set flow rate Q2 (second set hydraulic pressure, second set flow rate, second operating condition), the control value generation unit 53 refers to the pump efficiency data stored in the storage unit 57. Then, the operating condition that maximizes the operating efficiency of the hydraulic pump 34 is selected (FIG. 7, S117). This selection is performed in the same manner as the procedure for selecting the set angle θ1 and the set rotational speed N1 described above. The swash plate angle θ and the rotational speed N that are selected are represented as a set angle θ2 and a set rotational speed N2.
For example, in FIGS. 9A, 9B, and 9C showing the correlation between the operating condition and the operating efficiency at each of 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. Since the swash plate angles θx, θy, and θz are 80%, 70%, and 70%, respectively, the maximum efficiency Em2 is 80%, and the rotation speed N and the swash plate angle at which the maximum efficiency Em2 is obtained are 80%. 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.

When the set rotation speed N2 and the set angle θ2(θx) at which the maximum efficiency Em2 is obtained are specified, the command output unit 55 hydraulically supplies the command value CN2 corresponding to the set rotation speed N2 in the same manner as described above. It outputs the command value Cθ2 corresponding to the set angle θ2 to the swash plate angle control unit 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 adjusting unit 36 based on the acquired command value Cθ2. Then, 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 mold clamping pressure of the fixed mold 14 and the movable mold 15 increases (S119 in FIG. 7). ).
The control value generation unit 53 continuously acquires the detected discharge hydraulic pressure ρd, and continuously compares whether the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ2 (S121 in FIG. 7). If the detected discharge hydraulic pressure ρd has not reached the set hydraulic pressure ρ2, the servomotor 32 and the hydraulic pump 34 continue to operate under the previous conditions (No in S121 in FIG. 7).

On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ2, the control value generation unit 53 determines whether or not the boosting process should be completed (Yes in S121 of FIG. 7). That is, the control value generation unit 53 determines whether or not the detected discharge hydraulic pressure ρd overshoots the set hydraulic pressure ρ2 (FIG. 7, S123). For example, the allowable range Δρ is set, and if the detected discharge hydraulic pressure ρd exceeds the set hydraulic pressure ρ2+the allowable range Δρ, it is determined to be overshoot (S123 Yes in FIG. 7), and the detected discharge hydraulic pressure ρd is (set hydraulic pressure ρ2+allowable range Δρ) If it is the following, it is determined that the overshoot has not been reached (No in S123 in FIG. 7).

When the detected discharge hydraulic pressure ρd determines that the detected discharge hydraulic pressure ρd is overshoot, the control value generation unit 53 sets the preset rotational speed N2 of the servo motor 32 to the command output unit 55 in order to reduce the hydraulic pressure by a predetermined rotational speed Ns (where Ns< The command output unit 55 sends the command value CNs received to the servo control circuit 33 of the hydraulic pressure supply unit 30. The servo motor 32 is operated based on this command value CNs. In order to reduce the hydraulic pressure, instead of decreasing the set rotation speed N2 of the servo motor 32 to the rotation speed Ns, the servo motor 32 may be temporarily stopped or reversely rotated, or a predetermined valve (not shown) may be 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, it sends a command to the command output unit 55 to stop the operation of the servomotor 32, and the command output unit 55 receives this command. Then, 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 step-up process ends (S127 in FIG. 7). After that, a molten resin is injected from the injection cylinder 19 into the cavity formed by the fixed mold 14 and the movable mold 15, and an injection/pressure-holding step of holding the resin pressure in the cavity after the injection is completed is executed.

The mold clamping device 1 described above has the following effects.
The mold clamping device 1 operates under the conditions of the discharge hydraulic pressure ρ(ρ1, ρ2) and the swash plate angle θ(θ1, θ2) capable of operating at the maximum efficiency (Em1, Em2) according to the set mold clamping force F. Also, since the hydraulic pump 34 can be operated, the hydraulic pump 34 can always be driven with high efficiency.
Moreover, since the mold clamping device 1 sets the conditions for this highly efficient operation based on the pump efficiency data created in advance for the hydraulic pump 34, the conditions for highly efficient operation can be set accurately. 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 determines whether the discharge hydraulic pressure ρ reaches the set hydraulic pressure ρ1 depending on the operating conditions of the servomotor 32 and the hydraulic pump 34. To switch. Therefore, in the step-up process, the maximum efficiencies Em1 and Em2 are obtained in each of the first operating condition period in which the hydraulic pump 34 is required to operate at high speed and the subsequent second operating condition period in which high-pressure operation is required. The servomotor 32 and the hydraulic pump 34 can be operated at the set rotational 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 of maximum efficiency corresponding to the respective 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 device 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 end of the injection filling process of the injection device (not shown). You can also do it. Specifically, the set hydraulic pressure ρ2 may be used as the discharge pressure in the pressure holding process, which is a molding setting condition, and the set hydraulic pressure ρ1 may be an arbitrary pressure value lower than the set hydraulic 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 device 2 according to the second embodiment will be described with reference to FIG. 10. The configuration of the mold clamping device 2 is almost the same as that of the mold clamping device 1 except that the data relating to the efficiency of the servo motor 32 is added to the storage unit 57 and the control value generation based on the added data. Since the processing is performed by 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 regarding the servo motor 32 is stored in the storage unit 57 of the molding machine control unit 50. The motor efficiency data includes the efficiency data for the motor alone shown in FIG. 10A, the efficiency data for the amplifier shown in FIG. 10B, and the overall efficiency data shown in FIG. 10C. .. The servo motor 32 includes a motor main body and a servo amplifier that controls the supply of electric power to the motor main body. Therefore, the motor efficiency data also includes motor data regarding the motor main body and amplifier data regarding the servo amplifier. The total efficiency data is a combination of both motor data and amplifier data. Both 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 (hereinafter referred to as pump unit efficiency data) obtained by integrating the pump efficiency data with the overall efficiency data. ..
For example, in the total efficiency data of FIG. 10C, the efficiency is 86 to 88% when the rotation speed N is 1000 rpm and the output torque T is 200 Nm. For example, in the pump efficiency data shown in FIG. 4, the pump efficiency when the rotation 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. By performing this integration for the entire range of the rotation speed N and the output torque T in the overall efficiency data and the entire range of the rotation speed N and the input torque T at the swash plate angle θx, the pump unit efficiency data at the swash plate angle θx is obtained. .. 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 corrected efficiency data in which the efficiency of the servo motor 32 is added to the pump efficiency data. The flow of this integration is shown in FIG.

Now, a procedure for determining the combination of the swash plate angle θ and the rotation speed N that obtains 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 to in the procedure for selecting the highest efficiency Em1 (S105 in FIG. 7) and the procedure for selecting the highest efficiency Em2 (S117 in FIG. 7). The difference is that the data to be set is pump unit efficiency data. After that, 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 that are selected by referring 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 consideration. Therefore, the maximum efficiency considering the entire pump unit including the servo motor 32 and the hydraulic pump 34 is considered. It is possible to drive at, and energy consumption can be minimized.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described.
The mold clamping device 3 according to the third embodiment uses the detected discharge hydraulic pressure ρd and the set flow rate (third set flow rate) Q3 in order to determine the combination of the swash plate angle θ and the rotation speed N at which the maximum efficiency Em is obtained. To use. This is because the first and second embodiments use only the set hydraulic pressure ρ1 and the set flow rate Q1, that is, a predetermined value, whereas the discharge hydraulic pressure uses the detected discharge hydraulic pressure ρd. Differences in points.
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 rotation speed N that achieves the maximum efficiency Em. The procedure for determining is different. Hereinafter, description will be made with reference to FIGS. 12 and 13.

First, when the mold clamping force F is input as the 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 stored speed value that does not depend on the predetermined molding condition is specified (FIG. 12, S203). The discharge flow rate Q specified here is referred to as a set flow rate Q3 in order to distinguish it from a later-obtained flow rate.

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 also 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 rotation speed Nα to the servo control circuit 33 of the hydraulic pressure supply unit 30, and a command value Cθα corresponding to the set angle θα of 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 adjusting unit 36 based on the command value Cθα, so that the hydraulic pressure. The swash plate angle θ of the swash plate 35 of the pump 34 is controlled to drive the servo motor 32 and the hydraulic pump 34 under the third operating condition (FIG. 12, S205).

At this time, the pressure detector 41 of the hydraulic pressure supply unit 30 detects the discharge hydraulic pressure ρ (the detected discharge hydraulic pressure ρd) of the hydraulic oil flowing inside the discharge pipe 39, and the control value generation unit 53 determines the detected discharge hydraulic pressure. ρd is acquired as the discharge hydraulic pressure ρ required to discharge 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 condition (the set rotational speed N3 and the set rotational speed N3 and The set angle θ3) is selected (S207 in FIG. 12). The procedure of this selection is the same as that of the first embodiment, and thus the description thereof is omitted here.

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

When the set rotational speed N3 and the set angle θ3 that can obtain the highest efficiency Em3 are obtained, the command output unit 55 outputs the command value CN3 to the servo control circuit 33, similarly to the first embodiment, and 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 is obtained (S209 in FIG. 12), and the mold clamping pressures of the fixed mold 14 and the movable mold 15 are reduced. Ascend (FIG. 12, S211).
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 while the mold is being pressurized (S213 in FIG. 12). If the detected discharge hydraulic pressure ρd has not reached the set hydraulic pressure ρ3, the control value generation unit 53 again collates the detected discharge hydraulic pressure ρd and the set flow rate Q3 with the pump efficiency data stored in the storage unit 57. Then, the operating condition (the set rotational speed N31 and the set angle θ31) is selected so that the maximum efficiency Em31 with which the hydraulic pump 34 has the highest operating efficiency is obtained. When the set rotation speed N31 and the set angle θ31 at which the maximum efficiency Em31 is obtained are obtained, the command output unit 55 outputs the command value CN31 to the servo control circuit 33, and the command value Cθ31 is set at the swash plate angle control unit. Output to 37. Hereinafter, similarly, the servo motor 32 and the hydraulic pump 34 are operated under the condition that the maximum efficiency Em31 is obtained, and the mold clamping pressures of the fixed mold 14 and the movable mold 15 increase.
As described above, the detected discharge hydraulic pressure ρd and the set flow rate (third set flow rate) Q3 are used to determine the operation in which the combination of the swash plate angle θ and the rotation speed N at which the maximum efficiency Em is obtained is determined. Repeat until ρd reaches the set oil pressure ρ3 (No in S213 in FIG. 12).

On the other hand, when the detected discharge hydraulic pressure ρd reaches the set hydraulic pressure ρ3, the control value generation unit 53 switches 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 at a predetermined speed value stored in the storage unit 57 that does not depend on a predetermined molding condition. The set flow rate (fourth set flow rate) Q4 to be specified is newly specified, and the servo motor 32 and the hydraulic pump 34 are operated under the fourth operating condition of the set rotational 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 compares the detected discharge hydraulic pressure ρd and the set flow rate Q4, which have been continuously detected after the operating conditions are switched, with the pump efficiency data stored in the storage unit 57, and the hydraulic pump The operating condition is selected so that the maximum efficiency Em4 of 34 is the highest (step S219 in FIG. 13). The procedure of this selection is the same as that of the first embodiment, and thus the description thereof is omitted here.

If the set rotation speed N4 and the set angle θ4 that can obtain the maximum efficiency Em4 are obtained, the command output unit 55 outputs the command value CN4 to the servo control circuit 33, as in the first embodiment, and 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 (S223 to S231 in FIG. 13) until the boosting step is completed are the same as those in the first embodiment, the following description will be omitted.

In addition to the first and second effects shown in the first embodiment, the third embodiment described above uses the detected discharge hydraulic pressure ρd when the hydraulic pump 34 is actually driven to maximize the effect. Since the conditions for obtaining the efficiencies Em3 and Em4 are selected, it is possible to more realistically operate at the highest efficiency and 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, in order to determine 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 is used. In the first embodiment and the second embodiment, the set hydraulic pressures ρ1 and ρ2 have a magnitude relation of ρ1<ρ2, and are obtained by calculation from the mold clamping force F set as the molding condition, and the set flow rates Q1 and Q2 are Q1> In addition to the magnitude relationship of Q2, it is a fixed value regardless of molding conditions. On the other hand, the fourth embodiment is different from the first embodiment in that the set hydraulic pressures ρ1, ρ2 and the set flow rates Q1, 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, ρ2 and the set flow rates Q1, Q2 are calculated from the operating speed of the tie bar 17 set as the molding condition. The set flow rates Q1 and Q2 correspond to the discharge flow rates Qnc, Q1c, and Q2c in the present invention. Further, since the configuration of the mold clamping device 4 is almost the same as that of the mold clamping device 1, the description of the configuration of the mold clamping device 4 will be omitted. However, as shown in FIG. 1, the mold clamping device 4 includes a position detector 58 for the movable die plate 13.

[Procedure for pressure control and flow rate control]
The procedure for determining the combination of the swash plate angle θ and the rotation speed N that obtains the maximum efficiency Em using the pump efficiency data will be further described with reference to FIG. 14. This procedure is called so-called injection compression in which the movable die 15 and the fixed die 14 are clamped by controlling the moving die plate 13 at a predetermined speed and at a predetermined clamping force in a plurality of steps from a position separated by a predetermined distance. The process is performed while detecting the discharge hydraulic pressure ρ from the hydraulic pump 34, the discharge flow rate Q, and the position of the movable die plate 13 or the movable mold 15. In the present embodiment, the movable die plate 13 will be described by taking two stages as an example for the sake of simplicity of the number of stages of a plurality of stages for switching 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 to the input unit 51 of the molding machine control unit 50 as control set values. The setting switching position Ls and the mold clamping completion position Lc are input (FIG. 14, S301). 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, A first set oil pressure ρ1p of the hydraulic pump 34 required to generate 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 by referring to the speed-discharge flow rate conversion data (S303 in FIG. 14). Therefore, the first set hydraulic pressure ρ1p and the first set flow rate Q1p correspond to the first set hydraulic 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 pump efficiency data stored in the storage unit 57 is referred to, and the operating efficiency of the hydraulic pump 34 is the highest. The operating condition that becomes higher is selected (FIG. 14, S305). This selection is performed in the same manner as in the first and second embodiments, the set rotational speed N1 and the set angle θ1 at which the maximum efficiency Em1 is obtained are selected, and the servomotor 32 and the hydraulic pump 34 are based on these set conditions. The operation is performed (S307 in FIG. 14). As a result, the movable die plate 13 is moved toward the fixed die plate 12 (S309 in FIG. 14).

While the movable die plate 13 is moving toward the fixed die plate 12, the position detector 58 of the movable die plate 13 detects the position of the movable die plate 13, and the detected value is referred to as the 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). If the detected position L1 has not reached the setting switching position Ls, the control value generation unit 53 does not issue a switching 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. 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 (Yes in S311 in FIG. 14), the control value generating unit 53 performs a process of switching the setting angle θ1 and the setting rotation speed N1. That is, when the detected 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 to obtain the set hydraulic pressure ρ2p. At the same time, the set flow rate Q2p required to operate the tie bar 17 at the second mold clamping speed V2 is newly identified with reference to the speed-discharge flow rate conversion data (S313 in FIG. 14). Therefore, the set hydraulic pressure ρ2p and the set flow rate Q2p correspond to the second set hydraulic pressure ρ2c and the second set flow rate Q2c in the present invention, respectively.

After obtaining the set hydraulic pressure ρ2p and the set flow rate Q2p, the control value generation unit 53 refers to the pump efficiency data stored in the storage unit 57 and selects the operating condition that maximizes the operating efficiency of the hydraulic pump 34. (FIG. 14, S315). This selection is performed in the same manner as the procedure for selecting the set angle θ1 and the set rotational speed N1 described above. The swash plate angle θ and the rotational speed N that are selected are referred to as a set angle θ2 and a set rotational speed N2.

When the set rotation 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 stopped at the setting switching position Ls, or is not stopped, and the movable die plate 13 is continuously moved toward the fixed die plate 12 by moving the tie bar 17 (FIG. 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 (FIG. 14, S321). If the detected position L1 has not reached the mold clamping completion position Lc, the servo motor 32 and the hydraulic pump 34 continue to operate under the previous condition (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 outputs this command. In response to this, 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 ends (S323 in FIG. 14).
After that, the mold clamping state is maintained for a predetermined time, the resin in the mold is cooled and solidified, the movable mold 15 and the moving die plate 13 are opened, and the molded product is taken out.

In the fourth embodiment described above, the movable die plate 13 is switched at a predetermined speed and at a predetermined mold clamping force in a plurality of stages depending on the position of the movable die plate 13. It may be performed from the start or by the time-up of the timer starting from the switching position of a plurality of stages.
Further, in the present embodiment, an example in which the present invention is applied to the switching of the arbitrary moving speed and moving pressure of the moving die plate 13 in the injection compression process of the mold clamping device 1 has been shown. Instead, it may be applied to switching control of arbitrary moving speed and moving pressure in the injection filling process of the injection device.
Moreover, you may perform the pressure|voltage rise process of 1st Embodiment or 2nd Embodiment after the injection compression process of this embodiment.

In addition to the first effect and the second effect shown in the first embodiment, the fourth embodiment described above has set hydraulic pressures ρ1, ρ2 and discharge flow rates Q1, Q2 calculated from the set molding conditions. It is possible to operate the hydraulic pump 34 and the servomotor 32 at the highest efficiency and minimize the energy consumption regardless of the mutual size relationship of the above.

Although the preferred embodiments of the present invention have been described above, the configurations described in the above-described embodiments can be selected or changed to other configurations without departing from the spirit of the present invention.
For example, in the first to third embodiments, the set operating condition is collated with the pump efficiency data after starting the boosting step. However, in the present invention, the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that achieve the highest efficiency are specified in advance by collating the set operating conditions with the pump efficiency data, and this is used as the data. Can also be kept as In this case, after the boosting process is started, the set operating condition and the relevant data are collated to specify the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor at which the highest efficiency is obtained.
Further, in the first to fourth embodiments, the set flow rate Q and the set hydraulic pressure ρ are shown in two stages, but they may be switched by a plurality of stages of three stages, four stages... ..

In addition, in the first to fourth embodiments, examples in which the swash plate angle θ of the hydraulic pump 34 and the pump efficiency data of the swash plate angle θ stored in the storage unit 57 are 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. Can be obtained by Then, by comparing the pump efficiency data obtained by the interpolation calculation with the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate, the swash plate angle θ of the hydraulic pump and the electric motor rotational speed at which the maximum efficiency can be obtained. The hydraulic pump 34 and the servomotor 32 may be operated by selecting N. In this case, even if the number of pump efficiency data obtained by experiments or simulations such as numerical analysis for the hydraulic pump 34 or the servomotor 32 is small and the pump operation is insufficient in a wide range of conditions, By interpolating appropriate pump efficiency data, the hydraulic pump 34 or the servomotor 32 can be operated at the highest efficiency.

1, 2 and 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 Mold clamping cylinder 181 Mold clamping side chamber 182 Mold opening side chamber 19 Injection cylinder 20,21 Bearing Box 22 Servo motors 23, 24 Power transmission gear 25 Ball screw shaft 26 Guide rail 27 Linear bearing 28 Slide base 29 Half nut 30 Hydraulic pressure supply section 31 Hydraulic pressure source 32 Servo motor 33 Servo control circuit 34 Hydraulic pump 35 Swash plate 36 Angle adjusting section 37 Swash plate angle control unit 39 Discharge pipe 40 Hydraulic oil pipe 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)

Hydraulic actuator,
An injection molding machine that operates a hydraulic actuator, comprising: a hydraulic pressure supply unit that supplies hydraulic oil to the hydraulic actuator to operate.
The hydraulic pressure supply is
A variable displacement hydraulic pump by changing the swash plate angle θ,
An electric motor that drives a hydraulic pump,
A control unit for variably controlling the rotation 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 hydraulic pump operating condition and the hydraulic pump operating efficiency. By collating with the pump efficiency data, the swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that achieve the highest efficiency when operating at a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate are specified. At the same time, 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.
An injection molding machine characterized by that. Pump efficiency data is
Data on the operating efficiency of a single hydraulic pump, or
It is the correction efficiency data in which the efficiency data of the electric motor is added to the operation efficiency data of the hydraulic pump alone.
The injection molding machine according to claim 1. The specified hydraulic oil pressure and the specified hydraulic oil flow rate are
Consisting 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 preset discharge hydraulic pressure ρ is the discharge hydraulic pressure ρc calculated from the operation setting condition,
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 preset discharge hydraulic pressure ρ is the discharge hydraulic pressure ρc calculated from the operation setting condition,
The discharge flow rate Qn set in advance is the discharge flow rate Qnc calculated from the operation setting conditions,
The injection molding machine according to claim 3. The specified hydraulic oil pressure and the specified hydraulic oil flow rate are
The detected discharge hydraulic pressure ρd and the preset discharge flow rate Qn,
The injection molding machine according to claim 1 or 2. The preset discharge flow rate Qn is composed of the discharge flow rate Qns that does not depend on the operation setting conditions.
The injection molding machine according to claim 6. The injection molding machine according to claim 6, wherein the preset discharge flow rate Qn is a discharge flow rate Qnc calculated from operation setting conditions. A pump efficiency data is provided 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, and the swash plate angle θ of the hydraulic pump and the electric motor Specify the rotation speed N,
The injection molding machine according to any one of claims 1 to 8. The control unit
Pump efficiency data at the swash plate angle not stored in the storage unit is obtained by interpolation calculation based on the respective pump efficiency data of the swash plate angle θ and the swash plate angle θ stored in the storage unit.
The swash plate angle θ of the hydraulic pump and the rotation speed N of the electric motor that achieve the highest efficiency are obtained by comparing the pump efficiency data obtained by the interpolation calculation with the predetermined hydraulic oil pressure and the predetermined hydraulic oil flow rate. 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 consisting of a preset first set hydraulic pressure ρ1 and a preset first set flow rate Q1;
A second set hydraulic pressure ρ2 (however, ρ2>ρ1) set in advance, and a second operating condition consisting of a second set flow rate Q2 (however, Q2<Q1) set in advance,
The control unit
Until the detected discharge hydraulic pressure ρd detected reaches the first set hydraulic pressure ρ1, the swash plate angle θ1 of the hydraulic pump and the rotation speed N1 of the electric motor are specified by collating the first operating condition and 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 swash plate angle θ2 of the hydraulic pump and the rotation of the electric motor are checked by collating the second operating condition and the pump efficiency data. Specify the number N2 to control the operation of the hydraulic pump and the electric motor,
The injection molding machine according to claim 3, claim 4, claim 5, claim 9, or claim 10. The control unit
As a predetermined hydraulic oil pressure and a predetermined hydraulic oil flow rate,
A first operating condition consisting of a preset first set hydraulic pressure ρ1 and a preset first set flow rate Q1;
A second set hydraulic pressure ρ2 (however, ρ2>ρ1) set in advance, and a second operating condition consisting of a second set flow rate Q2 (however, Q2<Q1) set in advance,
The control unit
Until the detected discharge oil pressure ρd detected 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 to check the swash plate angle θ1 of the hydraulic pump, and , Specifying the rotation speed N1 of the electric motor to 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 detected detected hydraulic pressure ρd, the second set flow rate Q2, and the pump efficiency data are collated to check the inclination of the hydraulic pump. The plate angle θ2 and the rotation speed N2 of the electric motor are specified to 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 condition,
The first set flow rate Q1 set in advance is the first set flow rate Q1s that does not depend on the operation setting conditions, and
The preset second set hydraulic pressure ρ2 is equal to or higher than the first set hydraulic pressure ρ1 and is the second set hydraulic pressure ρ2c calculated from the operation setting condition,
The second set flow rate Q2 set in advance is equal to or less than the first set flow rate Q1 and is the second set flow rate Q2s that does not depend 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 condition,
The first set flow rate Q1 set in advance is the first set flow rate Q1c calculated from the operation setting conditions, and
The second set hydraulic pressure ρ2 set in advance is the second set hydraulic pressure ρ2c calculated from the operation setting condition,
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 consisting of a first set oil pressure ρ1p obtained by calculation and a first set flow rate Q1p obtained by calculation;
A second set hydraulic pressure ρ2p obtained by calculation, and a second operating condition consisting of a second set flow rate Q2p obtained by calculation,
The control unit
Until the detected position L1 of the movement target of the hydraulic actuator reaches the operation switching position Ls, the first operating condition and the pump efficiency data are collated to check the swash plate angle θ1 of the hydraulic pump and the rotation speed of the electric motor. N1 is specified to control the operation of the hydraulic pump and the electric motor,
Until the detected position L1 of the moving object reaches the operation completion position Lc, the swash plate angle θ2 of the hydraulic pump and the rotation speed N2 of the electric motor are specified by collating the second operating condition with the pump efficiency data. To control the operation of the hydraulic pump and the electric motor,
The injection molding machine according to claim 1 or 2. The hydraulic pump is to generate a mold clamping force on the moving mold through a tie bar,
Mold 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 required to generate the mold clamping force are associated with each other, and the set predetermined operation A speed and a discharge flow rate of the hydraulic pump necessary to operate the tie bar at the moving speed, and a speed-discharge flow rate conversion data which is data associated with each other;
The control unit
When the first mold clamping force F1 is set, the first set hydraulic pressure ρ1p is obtained by referring 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 by referring 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 by referring 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 by referring to the speed-discharge flow rate conversion data.
The injection molding machine according to claim 15.

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