JPH0796541A - Energy - saving injection molding machine - Google Patents

Abstract

PURPOSE: To provide an energy-conserving injection molding machine which saves more energy than those for conventional machines and keeps distinguished responsiveness. CONSTITUTION: An injection molding machine 10 incorporates a pump 26 driven by a variable speed motor 34 of a brushless DC type. The machine controller 15 outputs driving signals 40 to control the speed of the motor 34 so that the flow delivered by the pump 26 matches the hydraulic demand imposed during each phase of the machine operating cycle. This pump is connected with a responding pump controller 43 for selectively carrying out pressure compensation or flow compensation. The values of the motor driving signals 40 are calculated so that the motor 34/the pump 26 combination is operated at max. efficiency. Hydraulic transient response is further improved by connecting the output of the pump 26 with a gas-filled accumulator 48 by way of a check valve 49.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a hydraulically actuated injection molding machine that provides improved energy efficiency. More specifically, the present invention adjusts the displacement of a hydraulically actuated pump according to the various hydraulic actuation requirements imposed by the machine during different phases of the actuation cycle to provide the required displacement of the pump. Relates to a fluid pressure operated injection molding machine incorporating a device for saving energy by not significantly exceeding

[0002]

Injection molding is a method for converting material from one form or shape to another by consuming energy. The material, which is usually in the form of an array of solid pellets, is loaded into an injection molding machine and the pellets are first converted to the molten state by introducing energy in the form of heat and mechanical shearing. In order to inject the plasticized pressure-state material into the mold while the mold is closed tightly and has a cavity defining the final shape of the part to be manufactured, Energy is consumed. Additional energy is used to cool the material in the mold back to the solid state. The mold clamping device is then released and the molded part is released and the mold is closed again in preparation for molding the next part to be molded. The laws of physics require that the total energy input to the forming machine be balanced equally with the energy output.

In hydraulically operated injection molding machines, energy is input to the machine in the form of electrical energy.
Most of this energy is converted to hydraulically actuated fluid energy by an electric motor drivably coupled to a hydraulically actuated pump. The fluid provided by the pump serves to actuate various hydraulically actuated components, including electro-hydraulic actuated control valves and hydraulically actuated devices. The pressure or volume flow requirements for a hydraulic working fluid are not only changed from one given machine setting to another, but also at various settings of different phases of the machine's operating cycle. Even during the period, it changes significantly. For example, settings that require rapid injection of material into the mold require higher volumetric flow rates than are needed for slower injection rate settings. Also, the phase of the machine's operating cycle, such as the clamp release phase, typically requires a much higher hydraulic working fluid flow rate than the phase to cure the molded part. Hydraulically actuated injection molding machines must allow any maximum fluid pressure and / or flow rate requirements necessary to meet the maximum rated efficiency of the machine, but with less hydraulic actuated fluid pressure and / or volume. When operated at the conditions required to operate the machine, more energy was lost than the pressure and / or volumetric flow actually delivered by the pump.

In a machine having a fixed displacement hydraulically actuated fluid pump driven by a constant speed electric motor, the pump is of maximum mechanical capacity, even if the instantaneous hydraulic actuation requirement is significantly lower. It must be driven so as to constantly supply a sufficient flow rate so that the required amount can be satisfied. Excess flow, ie the difference between the actual flow delivered by the pump and the instantaneous demand, is propelled through the relief valve. In this way, energy is wasted. Some of this wasted energy is released in the form of heat, causing undesired heating of the hydraulic working fluid itself. Still more energy must be expended when raising the fluid temperature to a temperature that requires aggressive cooling to return the fluid to the proper operating temperature. In an effort to overcome these problems, various attempts have been made in the prior art to match the output of hydraulically actuated pumps with the demands imposed by the rest of the injection molding machine. Of.

One such contemplated solution is
It was to provide a hydraulically actuated injection molding machine having a fixed displacement hydraulically actuated pump driven by an AC motor with an adjustable speed drive such as a variable frequency or an inverter type drive. By changing the speed control input to the drive, the speed of the motor and thus the pump flow rate can be changed to more closely approximate the actual hydraulic actuation requirements. Unfortunately, however, such machine energy savings are only realized at the cost of machine performance. Since the moving parts of the motor / pump assembly cannot be accelerated or decelerated very quickly, the periodic response of the machine
This is the deterioration of the energy. As a result, the quality of the molded part can be adversely affected by changes in molding parameters such as shot weight of material, injection speed and injection pressure.

The assignee of the present application has sold a series of hydraulically actuated fastening machines under the trademark "VISTA". These machines guarantee only the flow rate needed to meet the load requirements, thereby reducing energy usage and heating of the hydraulic working fluid, axial piston, swash plate design variable discharge It uses a fixed speed AC motor to drive a volumetric pump. A hydraulically actuated feedback circuit is used to selectively provide either pressure or flow assurance of the pump output by moving the swashplate angle of the pump to change the stroke. Such a control action does not require acceleration or deceleration of the large inertial rotary portion of the motor / pump assembly, resulting in a significant response time as compared to the fixed displacement pump / variable speed AC motor machine described above. Be improved. A further improvement in the transient response is made by connecting the output of the pump to a gas filled accumulator. The output of this accumulator is a multi-function servo controlled directional valve forming a closed loop control circuit for injection speed, injection pressure, back pressure and melt pressure reduction.
controlled proportional dire
It is connected to a partial valve). Nevertheless, the energy savings made by the VISTA model machine were less than the savings made possible by the present invention.

[0007]

In view of the aforementioned drawbacks of the prior art, there is provided an energy saving injection molding machine that allows greater energy savings than the prior art machine and maintains outstanding response characteristics. It is an object of the present invention.

[0008]

According to a first aspect of the invention, there is provided an energy saving injection molding machine including a hydraulically actuated pump driven by a brushless DC motor. Such motors offer significant advantages in energy efficiency over prior art variable speed AC pump motors.

According to a second aspect of the present invention, a variable speed motor, preferably of the brushless DC type, is used to drive a variable displacement hydraulically actuated pump. An electronic machine controller supplies drive signals to the motor drive to control the speed of the motor according to desired molding parameters. This motor speed causes the output of the pump to substantially match the expected hydraulic load during a particular phase of the machine's operating cycle given the molding parameters input by the operator to the controller. Is selected. The controller is adapted to automatically output a new drive signal as the machine cycles through the phases of operation characterized by different hydraulically actuated loads. The pump delivery is managed by a pump controller which selectively adjusts the flow rate delivered by the pump in either pressure compensation or flow rate compensation mode. The pump controller can respond quickly to changes in load, thus providing improved transient response. To further improve this transient response operation, the output of the pump is connected to the gas filled accumulator via a check valve.

[0010]

The foregoing and other features and advantages of the present invention will be apparent to those of ordinary skill in the art by the following detailed description in connection with the drawings, in which like parts are designated by like numerals.

FIG. 1 shows a preferred embodiment of an injection molding machine 10 constructed in accordance with the present invention. The machine 10 includes a tightening unit 12 and an injection unit 11 attached to the tightening unit 12. Sequential actuations, timing actuations and quantitative values associated with the various actuations performed by these injection unit 11 and tightening unit 12 are electronic according to molding parameters input by the operator through the actuator interface 16 to the controller 15. This is performed according to a command from the machine control device 15. A number of feedback signals 18 received by the controller 15 from the injection unit 11 and the clamping unit 12 facilitate the operation of the closed loop control circuit. The injection control device 20 and the tightening control device 21 serve as an electro-hydraulic actuating interface between the machine control device 15 and the injection unit 11 and the tightening unit 12, respectively. Injection control device 20 and tightening control device 21 are known in the art and in accordance with various actuating signals received from the machine control device by multi-signal paths 23 and 24, respectively, injecting unit 11.
And an electrically controlled proportional valve arranged to generate the hydraulic actuation pressure and / or flow rate required to operate the tightening unit 12.
onrolled proportioning v
alv) and other hydraulic and electro-hydraulic actuators.

The fluid pressure working fluid is supplied from the pump 26 to the injection control device 20 and the tightening control device 21 by the manifolds 27 and 28. The pump 26 is connected to the storage tank 30 by a case extraction pipe 31 and a supply pipe 32, and is driven by an electric motor 34 which receives an electric input energy at 35. The motor 34 is preferably a brushless variable speed DC motor, but can also be suitably any other variable speed AC or DC motor according to some features of the invention. The motor 34 is mechanically connected to the pump 26 by a rotatable shaft 33. In order to conserve energy by matching the hydraulic actuation output of pump 26 to the demand during various phases of the machine 10 actuation cycle, the present invention controls the speed of motor 34 and shaft 33, thereby It is contemplated that the pump 26 be controlled by the drive signal 40 generated by the machine controller 15 in a manner as described in detail below. To this end, the drive signals for each phase of the operating cycle of the machine 10 from certain molding parameters input by the operator through the actuator interface 16 by the machine controller 15 during the setting of the machine 10. It suffices to note that we try to calculate the magnitude of. Such molding parameters determine the anticipated hydraulic actuation requirements during each phase of the machine's operating cycle.

The flow of hydraulic working fluid supplied by pump 26 is monitored by pump controller 43 via line 42. This pump controller 43, which will be described in more detail with reference to FIG. 3, is in communication with this pump 26 via a pipe 44 so as to actuate the pump 26, and by means of a signal path 46 from the machine controller 15 It is adapted to operate in either pressure compensation or flow compensation mode according to the electrical pressure or flow compensation signal supplied to the pump controller 43. The output of pump 26, which feeds manifolds 27 and 28, is preferably coupled to a gas filled accumulator 48 via a check valve 49 to improve hydraulically actuated transient response operation.

The accumulator 48 has a ballast loaded at an initial internal pressure that resists the flow of liquid into it. The design of such accumulators is known in the art. When the pressure of the pipe to which the accumulator 48 is attached exceeds the internal pressure of the accumulator, the fluid pressure working fluid becomes accumulator 4.
8 to compress the ballast. When the pressure in the tube drops below the internal pressure of the accumulator, the hydraulic working fluid is forced from the accumulator 48 into the tube. Therefore,
If the supply amount to the pump 26 and the motor 34 is behind the required amount for the flow rate generated by the opening degree of the valve of either the control circuit 20 or 21, the accumulator 4
8 quickly responds to this by temporarily making an additional demand. In this way, the accumulator 48
It provides a more accurate and quick response match of flow rate delivery to flow rate requirements.

The injection unit 11 includes an injection screw 52 which is rotatably connected to a hydraulically operated extruder motor 53 by a shaft 54. The direction and speed of rotation of the motor 53, and thus the direction and speed of rotation of the screw 52, are controlled by the flow of hydraulically actuated fluid directed from the injection controller 20 to the motor 53 by a pair of hydraulically actuated tubes 57 and 58. is there. Extruder motor 53 during the "extrusion run" of the machine operating cycle
A tube 58 exiting the output side of an electrically controlled throttle (not shown) located in the injection controller 20 for sensing the flow rate of the hydraulic working fluid to the pump controller 43 by the tube 56. It is connected. The purpose of the pump controller 43 will become clear in relation to the description of the pump controller 43 below with reference to FIG.

The injection screw 52 is housed in a barrel 60 having a nozzle end 61. The barrel 60 is in communication with a hopper (not shown), which is capable of being filled with moldable material, usually in the form of solid particles or granules. Screw 5
As the two rotate in one direction in the barrel 60, the barrel is filled with material, which is transformed into a molten plastic state by the mechanical shearing action of the screw 52. Plasticization of such molding material can be assisted by one or more electric heating devices (not shown) mounted in thermal contact with the barrel 60. As moldable material accumulates in the barrel 60 rearward (to the left in FIG. 1) from the nozzle end 61, the screw 52 causes the barrel 60 to move.
It is pushed backwards in the axial direction.

The screw 52 is a pair of fluid pressure actuating devices 6
Barrel 60 selectively at desired speeds by 3 and 64
The hydraulic actuators 63 and 64 may be extended or retracted within the fixed platen 66 and a platen 67 mounted for axial movement relative to the platen 66. Installed to work with. Actuators 63 and 64 fluidly communicate with injection control device 20 by a pair of tubes 69 and 70 which, when pressurized, pull back screw 52 within barrel 60, respectively.
It is also designed to be extended. To monitor the pressure at which the screw 52 is extended, a pressure transducer 72 connected to the tube 70 is adapted to send a return signal to the machine controller 15 via a signal path 73. The axial position of the screw 52 in the barrel 60 and its speed of movement are coupled to a platen 67 movable in a distance-sensitive relationship using a distance transducer 75 that communicates with a machine controller 15 by a signal path 76. Being watched. Both platens 66 and 67 are mounted on an axially movable sled 77 so that the screw 52 can be selectively retracted from the clamping unit 12 or moved into engagement therewith. ing. The axial movement of the sled body 77 is controlled by a fluid pressure actuating device 78, which is mechanically connected to the sled body and is connected to the pipe 8.
0 and 81 hydraulically actuate injection control device 20
Are linked to.

With continued reference to FIG. 1, the clamping unit 12 supports the mating portions 87 and 88 of the mold 89 1
It carries a face plate having a pair of opposing clamping surfaces 84 and 85. Although not a part of the present invention, this mold 89 is usually adapted to be supplied by the user of the machine 10 and its internal cavity 91 defines the shape of the part to be molded by the machine 10. Is included. The tightening unit 12 further includes a pair of fluid pressure actuating devices 9
4 and 95 to move the mold portions 87 and 88 into a selectively mating relationship (as shown) to close the mold 89 or separate the portions 87 and 88 to open the mold 89. Has become. Actuators 94 and 95 include tubes 97 and 98 as shown.
Is operated by the fluid pressure working fluid supplied from the tightening control device 21. A distance transducer 100, which may suitably include a linear potentiometer, is mounted between the clamping surfaces 84 and 85 in a distance-sensing relationship such that the machine controller 15 controls the distance between these surfaces by means of the signal path 101. It is supposed to monitor. A conventional ejector mechanism 104 includes one or more hydraulically actuated fluid conduits 10.
5, coupled to the tightening control device 21 to selectively extend one or more ejector pins 106 into the cavity 91 to facilitate removal of the molded portion from the cavity when the mold 89 is opened. I am doing it.

The tightening unit 12 further includes a mold 89.
Includes a device for selectively holding the forcefully closed state. A mechanical toggle mechanism may be suitably used for this purpose, but the embodiment of FIG. 1 utilizes hydraulically actuated mechanical action which causes the piston 110 to exert a greater hydraulically actuated pressure on the clamping surface. It can be selectively pressed against the back of 85. This pressure is the piston 1
It is generated within the interior volume 112 of a cylinder 113 which receives 10 in a slidably hydraulically sealed relationship. The internal volume 112 is adapted to be selectively fluidly connected to or sealed from the prefill reservoir 116 by a valve 117. This valve 117 includes a pair of tubes 119 and 1
It is adapted to be operated by the tightening control device 21 via 20. Valve 117 includes a moveable stem 122 adapted for sealing engagement with a valve seat 123 formed in the wall of cylinder 113. Volume 1
After 12 is filled by opening valve 117, valve 117 is closed, sealing valve stem 122 against valve seat 123. In order to keep the mold 89 in a tightly closed state, the internal volume 112 is under high pressure through a fluid pressure working fluid line 125 which is connected by the tightening control device 21 to an inlet port 126 formed in the wall of the cylinder 113. It is pressure actuated. The hydraulic working pressure in this volume 112 is monitored by a pressure transducer 128 by means of a pipe 125, which is in communication with the machine control 15 by means of a signal path 129.

The normal operating cycle of an injection molding machine, such as machine 10, is the "locker closed" phase, the "injection" phase,
It includes a number of phases, including an "extruder run" phase, a "clamp release" phase and a "release" phase. Each phase is differentiated to provide different hydraulic actuation requirements. The sequential actuation program in the controller 15 causes the electro-hydraulic actuation controller 2 to operate at the appropriate time.
The output of various actuation signals 23 for 0 and 21 is adapted to determine the sequential actuation, the timing actuation and the quantitative values associated with these phases. Energy is saved by adjusting the output of pump 26 so that the demands associated with each phase are not significantly exceeded. According to the present invention, yet another energy saving is realized by the novel use of a brushless DC motor driving a variable displacement pump of an injection molding machine and by adjusting the speed of this motor according to a specific drive signal. Of. In the preferred embodiment of the present invention, the motor 34 is a brushless DC model manufactured by Powertech of Charlotte, NC and is in the form of a 75 hp DPFG288T. The drive signal not only matches the output of the pump to the demands for each phase, but also provides the best efficiency except when the pump controller 43 makes adjustments to provide pressure or flow compensation, as is most desirable. It has been calculated to operate the hydraulically actuated pump / motor combination as obtained.

In the preferred embodiment, pump 26 preferably comprises a variable displacement pump, such as a vane pump or a piston pump. A preferred variable displacement pump with axial piston, moveable swashplate design is available from Rexroth, Bethlehem, PA as model AA4VSO, and pump 26, shown in more detail in FIG. 2, is a rotatable piston assembly. Housing 13 covered with a port plate 134 that houses 136
Includes 3. This port plate 134 is an inlet port 135a that is connected to the reservoir 30 of FIG.
And check valves 49 to provide manifolds 27 and 2
8 and an outlet port 135b connected to the accumulator 48. The piston assembly 136 includes a shoe 139 that slides along the surface of a tilted swash plate 140, and the piston 13 is reciprocally supported so as to be tiltable.
It includes a cylinder barrel 137 forming a cylinder receiving eight. The reciprocating motion of the piston 138 is caused by the rotation of the drive shaft 33 rotatably connected to the motor 34. The angle of the swash plate 140, and thus the stroke of the piston 138, can be varied by the control of a cylinder 142, which is connected to the pump controller 43 by a pipe 44 in a manner further described with reference to FIG. ing. The cylinder 142 is adapted to engage with the swash plate 140 and change the tilt angle of the swash plate according to a fluid pressure operation signal provided to the cylinder 142. Cylinder 142 is oriented along an axis perpendicular to the plane of FIG. 2 for reciprocal movement toward and away from the viewer. This reciprocating motion causes the tilting motion of the swash plate 140 by the cam operation.

In operation of pump 26, rotation of shaft 33 causes piston 138 to slide generally axially inside cylinder 137 as shoe 139 slides along the surface of slanted swash plate 140. When the piston is retracted within its bore, hydraulic fluid fills the cavity above the piston through the inlet port 135a. Piston 13
In the maximum retracted position of 8, the piston is in the outlet port 13
Start to match 5b. As the piston assembly continues to rotate, the piston is extended to expel pressurized hydraulic working fluid from port 135b. Thus, the instantaneous volumetric flow delivered by the pump 26 is related to the rotational speed of the shaft 33 and the tilt angle of the swash plate 140, the latter being changed by the operation of the cylinder 142 to either pressure or flow compensation. This is done selectively.

The pump controller 43 will now be described in more detail below with further reference to FIG. The pump controller 43 includes a flow compensation valve 150, a pressure compensation valve 157, an orifice 161, an electrical operating mode selection valve 165 and an electrically configurable pump pressure control valve 170, all of which are shown in FIG. Are connected as shown in. The high-pressure side output of the pump 26 is supplied to the valve 15 by the pipe 42.
0, 157 and 165. Fluid is adapted to be supplied from the reservoir 30 to the pump 26 by a pipe 32. On the low pressure side, both pump 26 and pump controller 43 are connected to reservoir 30 by pipes 31 and 59, respectively.

To operate the pump 26 in the flow compensation mode normally desired during the extrusion operation of the machine's operating cycle, the controller 15 provides a flow compensation signal to the multi-signal path 46.
Is to be given by. As a result, the valve 165
3 moves to the right in FIG. 3 so that pressure from tube 56 is applied by orifice 152 to the pilot side to the right of valve 150. The output pressure from the pump 26 appears by the pipe 42 on the left pilot side of the valve 150. As previously mentioned, the tube 56 exits from an electrically controlled extruder motor throttle valve located inside the injection controller 20. In the flow compensation mode,
The valve 150 operates to maintain the pressure drop across this throttle at the desired constant value. This value is
Can be electrically set by the machine controller 15 according to a flow compensation signal provided to the electrical input of the. This flow compensation signal is also provided to the pump controller 43 by the multi-signal path 46 shown in FIG.

If the pressure differential between the two pilots of valve 150 exceeds the desired electrically set value, the spool of valve 150 will move to the right in FIG. It is designed to be applied to the bottom of the pump cylinder 142. As shown more clearly in FIG. 3, this cylinder 142 is mechanically connected to a tiltable swash plate 140. Cylinder 142 typically includes a spring that provides a force that holds swash plate 140 in a position that provides maximum stroke to pump 26. The structure of the pump 26 is
It is desirable to operate the pump in this state whenever possible because it is designed to be most efficient when operating at or near maximum stroke. But if valve 1
Cylinder 142 is required to return valve 150 to its equilibrium position, provided that the movement of 50 provides sufficient pressure via tube 44 to the bottom of cylinder 142 to overcome the force of the spring. It operates to move the swash plate 140 only to shorten the stroke of the pump.
Therefore, the pump 26 supplies only the amount of fluid needed to maintain the desired pressure drop across the throttle valve in the controller 20 which controls the extruder motor 53.

This pressure compensation mode is selected by the controller 15 during all phases of the operating cycle of the machine 10 except the extruder run phase. To do so, controller 15 deactivates valve 165 to return it to the normal position shown in FIG.
It should be given to 0. The output of pump 26 is also the pilot and orifice 161 to the left of valve 157.
Given on the left side of. The left side of the orifice 161 is the valve 15
7 to both the right pilot and the input side of valve 170. Flow is prevented from passing through valve 170 unless the pressure at the input of valve 170 exceeds the desired value provided to valve 170 in the form of a pressure compensation signal from controller 15. As a result, the orifice 1
No flow through 61, pump output pressure is equal and valve 1
57 appears to both pilots, which causes valve 157
Are held in the normal position shown in FIG. During this time, the spring in valve 142 causes the swash plate 14 of pump 26 to
The zero is held at a position where the maximum stroke is almost given, and the operation with the maximum efficiency is performed.

If the output pressure of the pump, which appears at the input (to the right) of the valve 170 through the orifice 161 by the pipe 42, exceeds the pressure compensation value provided to the valve 170, the valve 170 is connected to the pipes 59 and 31. Then, the discharge to the storage tank 30 is started. This flow has a pressure drop of orifice 1
So that it appears across 61, which allows valve 15
Move 7 to the right. As a result of this movement, valve 157 connects tube 42 to tube 44, thereby providing hydraulic working fluid pressure to the bottom of cylinder 142. When this pressure is sufficient to overcome the spring in the cylinder 142, the pump 26 will perform stroke destroke as described above. This reduces the output of pump 26, tending to reduce the pressure drop across orifice 161 until the pressure appearing at the input of valve 170 does not exceed the pressure compensation value. This allows valve 170 to
The flow to 0 is stopped and the valve 157 is returned to the normal position shown in FIG. Therefore, in the pressure compensation mode, the pump 26 is controlled by the controller 15 by the valve 17
It is arranged to supply only the flow necessary to maintain the desired pressure supported by the pressure control signal applied to zero.

The desired molding parameters, represented as set points in the engineering unit, are entered by the operator via the actuator interface 16 into the memory of the controller 15. In the preferred embodiment, controller 15 is a CAM manufactured by Cincinnati Miracron Plastic Division of Batavia, Ohio.
It is an AC XTL controller. The method of entering molding parameters into this controller is described in Vista Hydraulic-C, which is incorporated herein by reference in its entirety.
See E-User's Manual, publication number PM-430, for details. This CAMAC XTL controller is a default value for all set points of the machine to cause a standard machine cycle.
Have. All set points operated by the operator are displayed in menu 11-28 of the above manual.

The controller 15 contains a program which translates each set point from the engineering unit into a mechanical unit representing the output signal value generated by the controller 15. These signals are the actuation signals provided to the electro-hydraulic actuation controllers 20 and 21 by signal paths 23 and 24, and the pump controller 43 by signal path 46.
And pressure compensation signals supplied to the motor and motor 3
Drive signal 40 to be supplied to the four drive devices.
These signal values are calculated by the controller 15 from the flow rates required to operate the machine during one phase. For example, the flow velocity required to obtain an injection velocity of 38.1 cm / sec (15 in / sec) is the following formula:

[0030]

[Equation 1]

Where 15 is the set point, F is gallons per minute (GPM), A is the area of the actuator to be moved, and the remaining term is the conversion factor. Thereby, the required signal value (eg voltage) is calculated as a linear proportional value of the ratio of the calculated flow velocity to the maximum flow velocity. Continuing with this example, the voltage across the valve is

[0032]

[Equation 2]

Where D _cal is the calculated flow velocity F,
D _max is the maximum flow rate of the pump 21, and V _max is the voltage that drives the appropriate control valve to the fully open state. As is known in the art, the calculated voltage has an offset value (of
It is preferably adjusted to account for leaks and other small losses in the machine by adjusting the fset value). Once each signal value is calculated, it is stored in the program sequence operating memory of controller 15. At that time, the value of the given signal is calculated, and the value calculated for each phase is
It is important to note that the appropriate signal value to be output during the corresponding phase is adapted to be stored in the sequential operating memory at the location chosen for the controller 15 to output. .

Once all setpoints have been converted to machine units, the sequence program memory of controller 15 has all that is needed to drive the sequence of the machine through each phase of the complete injection molding cycle. It is made to include the signal of. To sequence the machine through one injection molding cycle, the controller 15 outputs various signal values from the sequence program memory in the proper sequence and timing relationship.

The drive signal 40 controls the speed of the motor 34, and thus the output of the pump 26, to the hydraulic actuation demand given during each phase of the machine cycle according to the molding parameters input by the operator. It is designed to ensure that the pump delivers only the flow rate required for setpoint performance to match. To calculate the drive signal, the required flow velocity calculated for each phase is calculated by the motor 34
Is related to the maximum voltage to operate at full speed. For example, the drive signal required to drive the motor 34 is according to the following formula.

[0036]

[Equation 3]

That is, it is calculated by the above formula.

Where D _cal is the calculated flow velocity, D _cal
max is the maximum pump discharge amount, and V _max is the voltage required to drive the pump 21 at the maximum discharge amount. If this relationship between drive voltage and pump output is not linear, a calibration table containing the exact linear adjustment factors is provided by controller 15.
It is arranged to correct the calculated drive signal value stored in the memory of. The drive signal for each phase is a valve machine parameter (valve machine parameter) that is provided by the controller 15 as described above.
parameters are stored in the sequential operating program memory.

Once the controller 15 has output the actuation signal value from the sequential actuation program memory to the controllers 20 and 21, the controller 15 monitors the responsive action of the tightening unit 12 or the injection unit 11 to obtain the set point. Make sure to confirm that. To do so, the controller 15 first reads the value of the feedback signal 18 from the transducer associated with the control action. For example, the pressure transducer 7
2 is connected to a fluid pressure working fluid pipe 70 leading to screw actuators 63 and 64. To verify the injection pressure, controller 15 reads a signal from pressure transducer 72 to verify that the actual pressure in tube 70 corresponds to the desired pressure. If the signal from the pressure transducer 72 indicates an over or under pressure, the controller 15 changes the injection actuation signal to the injection controller 20 to increase or decrease the flow through the valves in the circuit. Let it work. The pressure transducer 128 is arranged to monitor the clamping pressure in a similar manner. Similarly, the distance transducers 75 and 100 enable the controller 15 to provide closed loop control of injection speed and clamp position, respectively.

A flow chart illustrating the generation of signal values for machine 10 by controller 15 is shown in FIG.
Is shown in. The first block shows the input of shaping parameters for the various phases to the memory of the controller 15 through the actuator interface 16. This procedure is performed according to the manual incorporated into the present application as described above.

For each molding parameter, the program in the controller 15 calculates the pump flow rate of the second block of FIG. 4 required to obtain the molding parameter. This calculation is performed according to the formula for D _cal described above.

Utilizing the calculated flow rate, the program carries out the actuation of the third block of FIG. 4, which is the calculation of the actuation signal. These values correspond to the actuation signals 23 and 24 supplied to the injection control device 20 and the tightening control device 21 and are adapted to control the values in these control devices.

Similarly, the program is a calculation driving signal value (Calculate Driving Signal).
Utilizing the calculated flow rate to implement the fourth block of FIG. 4, which is Value). This program determines the magnitude of drive signal 40 required to drive motor 34 at the correct speed to energize pump 26 to obtain the calculated flow rate. This calculation is, if necessary, linear correction (piecew) for each part as described above.
It can be adjusted by utilizing a calibration table to perform the ise linear correction.

The fifth block in FIG. 4 requires utilizing the calculated flow rate and an appropriate pressure limiting factor. This factor is part of the program and is a few kg / cm ² (hundreds of ps) above the pressure generated at the calculated flow rate.
The pressure i) is desirable. Calculated flow rate,
The sum of the pressure and pressure limit factors give rise to the value of the pressure compensation signal output to valve 170 for pressure compensation. A signal value is also generated that moves the mode select valve 165 to the pressure compensation mode.

Similarly, the fifth block in FIG. 4 is executed.
The program part is also several kg / cm ²(Hundreds of psi) total
Utilizing the calculated flow velocity and flow limiting factor,
Calculate the amortization value. The mode selection valve 165 is used to supplement the flow rate.
A signal value for setting the compensation mode is also generated.

In the sixth block of FIG. 4, the program stores all generated values in the program sequence operating memory. The controller 15 outputs appropriate signals corresponding to these values to cycle the machine 10 throughout the injection molding cycle.

In operation, a typical machine operating cycle consists of a number of separate phases, each usually requiring a different hydraulic working pressure and / or flow rate. These phases include clamp closures, injections, extrusion runs, clamp release and / or discharge phases.

In operation, the machine 10 sequentially executes a number of successive phases as instructed by the controller 15. The first phase that is normally performed is the tightening closure phase. The machine controller 15 retrieves the multiple drive signal value for the motor speed from the programmed sequence operation memory and outputs it to the motor 34 as a multiple drive signal. The motor 34 changes its speed to match the drive signal and causes the output shaft 33 to rotate at the commanded speed. This rotational output drives the pump 26 to provide a calculated flow rate to effect the clamp closure phase. The flow from pump 26 is manifold 28 and / or 2
7 to the injection and tightening control devices 20 and 21. The controller 15 also searches for the pressure / flow compensation signal value and outputs the flow / pressure compensation signal to the pump controller 43. These signals put pump controller 43 in a pressure compensation mode to set the proper pressure on valve 170.

In connection with the output of the drive signal 40, the machine controller 15 also controls the injection and clamping controllers 20 and 2.
Search for an actuation signal for proportional control of the valve in 1. These actuation signals are output to the injection controller 20 along the multi-signal path 23 to close all valves in the injection controller 20. This is because no movement of the mechanical component performing the injection is necessary during this phase.

Tightening controller 2 from machine controller 15
The actuation signal for 1 goes through the passage 24 and the tightening control device 21.
And set the proportional control of the closure valve. When opened, this valve allows a flow of hydraulic working fluid to enter tube 97 from manifold 28. This tube 97
The flow through causes the hydraulic actuators 94 and 95 to be pushed towards the fixedly mounted ends. This movement forces the hydraulic working fluid behind the actuator through the tube 98 into the reservoir 30. When the hydraulic actuators 94 and 95 are traversed, these actuators draw the rear clamping surface 85 towards the front clamping surface 84. The rear molding portion 88 connected to the rear tightening surface 85 is adapted to close the mold 89 in combination with the front tightening portion 87 attached to the front tightening surface 84.

When the rear tightening surface 85 approaches the front tightening surface 84, the control device 15 monitors the distance traveled by the tightening surface 85 by the signal from the distance converter 100 through the signal passage 101. As the rear tightening surface 85 approaches the front tightening surface 84, the controller 15 outputs an actuation signal to change the proportional control of the tightening closing valve in the tightening controller 21 to gradually close the valve. Eggplant This slows the movement of the rear clamping surface 85 towards the front clamping surface 84 and protects the mold 89 from being damaged by impact.

In order to accumulate and hold the pressure for holding the clamping surfaces 84 and 85 together, the machine controller 1
5 searches for another drive signal and outputs a new drive signal to the motor 34. This signal drives the pump 26 at the flow rate required to build up the hold pressure. Similarly, controller 15 outputs a new flow / pressure compensation signal to adjust the pressure compensation mode of pump controller 43 to the new flow rate.

The machine controller 15 now has a signal path 24
The operation signal is output to the tightening control device 21 to open and close the tightening holding valve. When the tightening retention valve is opened, the flow of hydraulic working fluid from the pump 26 through the manifold 28 flows through the pipe 119 to the tightening extraction valve 117, which then passes through the pipe 120 to the reservoir 30. This valve is discharged. The valve stem 122 is drawn to the valve seat 123 by the valve 117.

The control device 15 of the machine then searches for another actuation signal and outputs the actuation signal to the tightening control device 21 via the signal path 24 to open the tightening pressure valve in the control device 21. This tightening pressure valve allows hydraulic working fluid to flow from pump 26 to volume 112 through inlet port 126 of cylinder 113. This fluid flow is contained in the volume 112 in the piston 110 and the tightening cylinder 1.
A pressure is generated that pushes 13 away from each other. This pressure also locks the valve stem 122 to the valve seat 123. The machine controller 15 is a pressure transducer 12.
By means of 8, the pressure generated in the volume 112 via the signal line 129 is read out. When the pressure indicated by the pressure transducer 128 reaches a predetermined level previously input by the operator, the machine controller 15 closes the tightening pressure valve to retain the fluid in the volume 112. . To do this, the control unit 15 controls the signal path 2
An operation signal is output to the tightening pressure valve in the tightening control device 21 through 4. The pressure generated by the fluid in the volume 112 holds this pressure in order to hold the clamp and mold together and to perform the cycle injection and cooling phases of the machine without the need for additional fluid flow from the pump 26. To hold.

The next operating phase to be performed is the ejection phase.
The machine controller 15 retrieves the new drive signal from the sequence program memory and outputs the drive signal to the motor 34 to change the motor speed to change the output of the pump to meet the expected demand. Eggplant The machine controller 15 also reads the flow / pressure compensation signal value and outputs a corresponding flow / pressure compensation signal to the pump controller 43. Since the valve in the tightening control device 21 is closed by an actuation signal from the machine's control device 15 at the time of closing the tightening closing cycle, the flow of fluid is controlled by the tightening control device 21.
Instead of being directed at, it operates to move mechanical injection actuation components.

The machine controller 15 searches for actuation signal values for proportionally controlling the valves in the injection controller 20,
This operation signal is sent to the injection control device 20 via the signal path 23.
Pass through. The control of the first proportional valve provided by the controller 15 of the machine in the injection operating phase is the injection forward valve.
e) is opened to allow the flow of hydraulically actuated fluid from the manifold 27 which acts to push against actuation of the hydraulically actuated device 78 by the tube 81. The fluid discharged from the actuator 78 flows through the pipe 80 to the reservoir 30. The actuator 78 serves to push the injection unit 11 towards the front clamping surface 84. The nozzle end 61 of the barrel 60 is assembled in the opening of the front tightening surface 84. Injection unit 11
When the machine approaches the front tightening surface 84, the machine controller 15 outputs an actuation signal to the injection controller 20 to gradually close the valve to allow the flow of hydraulic working fluid towards the actuator 78. . This is done to prevent the injection unit 11 from hitting the front tightening surface 84.

The machine controller 15 now has a motor 34
To output a new drive signal 40 corresponding to the drive signal value of the program sequence operating memory for. This signal causes the speed of the motor to change, thereby causing pump 26 to provide the correct flow rate for injecting material into mold 89 at the desired speed and desired pressure. Control device 1
5 also outputs a flow / pressure compensation signal to the pump controller 43 according to the flow / pressure compensation value stored in the sequential operation memory.

The machine controller 15 now outputs an actuation signal for opening the screw advance valve to the injection controller 20 via the signal path 23. Fluid flows to actuators 63 and 64 and causes injection screw 52 in barrel 60 to
Is pushed forward toward the front tightening surface 84. As the injection screw 52 moves forward, it injects the pre-melted and plasticized material in the barrel 60 through the nozzle end 61 and into the cavity 91 of the mold 89.

The speed of plasticized material entering the mold 89 is controlled by the machine controller 15 which outputs appropriate drive signals to the motor 34. These drive signals change the speed of the motor 34, which in turn changes the flow rate of the pump 26. As these flow rates change, so does the force applied to the actuators 64 and 63 connected to the screw 52. The machine controller 15 varies these drive signals to vary the injection rate based on the pressure reading received from the pressure transducer 72 via the tube 73. The signal from the pressure transducer 72 is used to confirm that the correct injection speed previously input by the operator is obtained. The machine controller 15 outputs an actuation signal to close the screw advance valve when a signal (from the distance transducer 75) indicating that the screw 52 is in the end of travel state is received via the signal passage 76. Two
Output to 0.

If the sprue breaking action
When the ak action) is programmed, the machine controller 15 is adapted to change the pump flow rate by outputting a new drive signal 40 to the motor 34. This causes controller 15 to send an actuation signal to injection controller 20 via signal path 23 to open the valve, allowing the flow of hydraulic working fluid to reverse the motion of actuator 78. This flow allows the injection unit 11 to be retracted from the front tightening surface 84. This action is used to prevent heat transfer from the barrel 60 to the mold 89. If the heat transfer is void 9
If the cooling of the material in 1 is to be prevented, this sprue breaking action is usually not necessary.

The machine controller 15 now outputs an actuation signal to the injection controller 20 to gradually open the valve connecting the tubes 69 and 70. This allows the actuators 63 and 64 to respond to the mechanical force exerted against the screw 52 as described below.

The next operating phase performed by controller 15 is the extruder operation and cooling phase. Here, the control device 15 causes the new drive signal 40 to the motor 34 to change the output of the pump. The controller 15 also outputs a flow / pressure compensation signal to move the mode selection valve 165 of the pump controller 43 to the left to select the flow compensation mode. Another signal is provided to the flow compensation valve 150 to indicate a predetermined flow rate limitation.

This causes the machine controller 15 to output an actuation signal to the throttle valve, which is
Allows a flow of hydraulically actuated fluid to flow through a tube 58 to a hydraulically operated or pusher motor 53 and then through a tube 57 to a reservoir 30. The motor rotates the injection screw 52 in response to this flow. At this time, pellets from a hopper (not shown) enter the barrel 60. In this way the pellets meet the rotating screw 52 and the mechanical shearing action provided by the screw 52 melts the pellets. The melted material is pushed forward by the vanes in the screw 52 toward the nozzle 61 of the barrel 60. As this plasticized material accumulates on the front of barrel 60, it provides back pressure to screw 52. Since the screw 52 is not intended to be held in place by the flow through the actuators 63 and 64, the screw is retracted to move the actuators 63 and 64.

When the machine controller 15 senses a change in pressure from the actuators 63 and 64 by the pressure transducer 72 along the passage 73, the controller 15 causes the injection controller 20 to move.
Gives an injection signal to the screw control valve by
It is adapted to shut off and retain the fluid within the actuators 63 and 64. A solid shot of the plasticized material is formed in barrel 60 as the actuator resists this pressure exerted by the plasticized material. Once this pressure reaches a predetermined level already input by the operator, the machine controller 15 provides a new actuation signal to the screw control valve which causes it to flow through tubes 69 and 70. So that the screw 52 can be retracted.
Here, the plasticized material fills the barrel 81 as the screw 52 rotates. As indicated to the controller 15 by the distance converter 75, the screw 5
When 2 traverses the barrel 60,
The control device 15 receives the injection control device 20 through the signal path 23.
Gives a signal to close the screw control valve in. Another actuation signal is also output to the injection controller 20 to close the pusher throttle valve connected to the fluid pressure actuated motor 53 and stop the rotation of the screw 52.

The material in the cavity 91 is cooled while the screw 52 is retracted and rotated to create an injection section of plasticized material. When this material cools in cavity 91 of mold 89, an injection molded part is formed.

The machine controller 15 now initiates the tightening release phase. At the beginning of this phase, the machine controller 15 again adjusts the speed of the motor 34 so that the correct flow rate from the pump 26 for the clamp release phase is obtained. The flow / pressure compensation signal is also output to the pump controller 43, actuating the flow / pressure compensation valve to return to the pressure compensation mode. The controller also sends another signal to the pump controller 43 to set a new pressure on the valve 170 (FIG. 2).

The machine controller 15 outputs an operation signal to the tightening controller 21 to open the tightening holding valve. Volume 11
The hydraulic working fluid in 2 now leaks from this volume 112 and prefills the reservoir 116 behind the cylinder 113. After waiting a predetermined amount of time, the tightening control device 21 receives an actuation signal from the machine control device 15, which opens the valve and causes the hydraulic working fluid from the pipe 120 to the extraction valve 117. It flows in and reverses the movement of the valve stem 122. The valve stem 122 has a volume of 112
When pushed therein, a more direct large diameter passageway is formed for the fluid in volume 112 to return to prefill reservoir 116. Once the valve stem 122 has a volume of 1
When fully extended into 12, the machine controller 15 provides an actuation signal to the tightening controller 21 via the passage 24 to stop the flow from the hydraulically actuated tube 120 to the valve 117.

The machine controller 15 now sets the pump controller 43 and the pump 26 to output a new drive signal 40 and a new flow / pressure compensation signal to release the clamp. When the clamp holding pressure is consumed, the machine controller 15 provides an actuation signal to the clamp controller 21 through the signal passage 24 and fluid flow through the hydraulically actuated fluid line 98 to the actuators 94 and 95. A fluid pressure working fluid line 97 discharges fluid from the actuating device to the reservoir 30. The flow against the actuators 94 and 95 pushes the rear clamping surface 85 and the attached rear mold part 88 away from the front clamping surface 84 and the front mounted mold part 87. Here, in addition, the machine controller 15 monitors the distance traveled by the rear clamping surface 85 by means of a signal received from the distance converter 100. When the rear clamping surface 85 approaches the end of the movable distance of the actuators 94 and 95, the machine controller 15 provides an activation signal to the clamping controller 21 to slow the flow to the actuators 94 and 95. This reduction in velocity continues until the flow is stopped and the back mold section 88 is separated from the front mold section 87.

The machine controller 15 now carries out the discharge phase of the cycle. After adjusting the pump output and pump control, the machine controller 15 provides an actuation signal to the tightening controller 21 through the signal path 24 to drive the ejector 106 via the tube 105. This ejector applies a pressing force to the molding portion formed in the mold 89 during the cooling phase and discharges it. The molded portion falls to the portion below the tightening unit 12. As a result, the gate (not shown) is opened and the molded portion is collected. Next, the machine control device 15 becomes the tightening control device 2.
1 is applied to reverse the flow to ejector 106 and retract ejector 106 to complete the machine cycle.

From the foregoing description, the pump controller 43 is associated with the variable displacement pump 26 to provide quick and accurate control over the output of the pump 26 in a selectable and pressure and / or flow compensating action. It is understood to provide a device for performing. Furthermore, the present invention allows the motor 3 to be driven by the drive signal 40 calculated according to the desired molding parameters.
By adjusting the speed of 4 to provide a device for matching the output of pump 26 to the anticipated hydraulic actuation requirements associated with each phase of the actuation cycle. As a result, pump 26 and motor 34 can be operated at or near maximum efficiency for most of the time. The motor / pump combination selected for use in the preferred embodiment is most efficient when the pump is operated at or near maximum stroke. However, it will be appreciated by those skilled in the art that other motor / pump combinations may be most efficient when operated in other operating areas. Therefore, for the greatest energy savings, the most efficient operating conditions for a given motor / pump combination should be chosen so that the pump will run at all times, except when swaying transients. It must be done.

In a variant of the invention, the pump 26
Includes a fixed displacement pump, the pump controller 43 is omitted, and the motor 34 includes a brushless DC motor. The speed of the motor is of a value calculated to substantially match the flow delivered by the pump during each phase of the machine cycle with the hydraulic actuation requirements expected during each phase. It is controlled according to the drive signal. Although the energy savings achieved by this variant of the invention are not as great as the energy savings possible with the preferred embodiments described above, the combination of variable speed AC motors and fixed displacement pumps known in the prior art does. When compared, this variant of the invention results in improved energy efficiency and a more precise and wide range of adjustments to the motor speed and thus the output of the pump.

Although the present invention has been described in the context of a hydraulically actuated injection molding machine, those skilled in the art will appreciate that the present invention is a hydraulically actuated injection reaction molding machine.
nreaction molding machine
It is understood that it is also applicable to other hydraulically actuated plastics processing machines such as e).

[0073]

Since the present invention is constructed as described above, by providing an injection molding machine including a hydraulically actuated pump driven by a brushless DC motor, more energy is provided than prior art machines. An energy-saving injection molding machine is provided that allows for energy savings and yet has outstanding response characteristics.

[Brief description of drawings]

FIG. 1 is a schematic circuit diagram of an injection molding machine constructed according to the present invention.

2 is a cross-sectional view of a variable displacement pump that is preferably used as the pump shown in FIG.

3 is a schematic circuit diagram showing the pump control device of FIG. 1 in more detail.

FIG. 4 is a block diagram showing a method of inducing a motor drive signal by the control device of FIG. 1.

[Explanation of symbols]

 10 Injection Molding Machine 11 Injection Unit 12 Tightening Unit 15 Machine Control Device 16 Actuator Interface 18 Feedback Signal 20 Injection Control Device 21 Tightening Control Device 23 Multi-Signal Passage 24 Multi-Signal Passage 26 Pump 27 Manifold 28 Manifold 30 Storage Tank 33 Axis 34 Electric Motor 40 Drive signal 43 Pump control device 46 Signal passage 48 Gas filling accumulator 49 Check valve 52 Injection screw 53 Fluid pressure operated extruder Motor 54 Shaft 60 Barrel 63 Screw 52 fluid pressure operated device 64 Screw 52 fluid pressure operated device 66 Fixed Platen 67 Movable Platen 72 Pressure Transducer 73 Signal Passage 75 Distance Transducer 76 Signal Passage 78 Fluid Pressure Actuator 84 Clamping Surface 85 Clamping Surface 87 Mold 89 Intersection 88 Mold 89 Matching part 89 Mold 91 Inner space of mold 89 94 Fluid pressure operating device 95 Fluid pressure operating device 100 Distance converter 101 Signal passage 104 Ejector mechanism 106 Ejector pin 110 Piston 112 Internal volume of cylinder 113 113 Cylinder 116 Pre-filling storage tank 117 Valve 122 Stem of valve 117 123 Valve seat 126 Inlet port of cylinder 113 128 Pressure transducer 129 Signal passage 133 Housing 134 Port plate 135a Inlet port 135b Outlet port 136 Piston assembly 137 Cylinder barrel 138 Piston 139 Shoe 140 Swash plate 142 Cylinder 150 Flow rate Compensation valve 152 Orifice 157 Pressure compensation valve 161 Orifice 165 Electrical operating mode selection valve 170 Pump pressure control valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Edward A. Correy, Rustic Wood, Cincinnati, Ohio, USA 1929 (72) Inventor Harold Jay. Faig Cincinnati, Ohio, United States, Spinning Wheel Lane 2244

Claims (10)

[Claims] 1. (a) supporting the first and second portions of the mold and selectively moving these portions into a spaced relationship to open the mold, and into a mating relationship to close the mold; A tightening mechanism that strongly holds the closed mold in this way, and (b) is connectable to the tightening mechanism and the mold, plasticizes a material, and injects the plasticized material into the mold to form a molded product. An injection mechanism for forming a closed portion, (c) a fluid pressure operating device connected to at least one of the tightening mechanism and the injection mechanism and operating the same, (d) connected to the fluid pressure operating device An electro-hydraulic actuation control device for supplying a hydraulic actuation fluid to the actuation device in response to a predetermined electrical actuation signal; and (e) the electro-fluid actuation control device. And fluid storage A pump device connected to the device for supplying a hydraulic working fluid to the electro-hydraulic actuation control device; and (f) a hydraulic working fluid of the pump device operably connected to the pump device according to a drive signal. A brushless variable speed DC motor for adjusting the discharge rate of (g), (g) generating the drive signal according to programmed molding parameters, sequenced and timed operation inputs, and (ii) required fluid discharge Discharge of the hydraulic working fluid required to be supplied by the pump device during at least a portion of a particular phase of operation of the machine to obtain the programmed input without significantly exceeding the volume. And a controller for generating said drive signal according to one of a number of stored values each calculated according to . 2. A check valve arranged between the pump device and the electro-hydraulic actuation control device, and an accumulator arranged between the electro-hydraulic actuation control device and the check valve. The energy-saving injection molding machine of claim 1 including a device. 3. The energy saving injection molding machine of claim 1, wherein the pump device comprises a fixed displacement pump. 4. The energy-saving injection molding machine of claim 1, wherein the pump device comprises a variable displacement pump. 5. A pressure guarantee mode such that (i) the pump provides only the flow rate necessary to maintain the pressure substantially determined according to the pressure signal generated by the controller, and (ii) A control to selectively actuate the pump device in at least one of a flow guarantee mode such that the pump supplies only a flow rate required to maintain a flow rate determined according to a pressure signal from the control device. An energy-saving injection molding machine as claimed in claim 4, including a device and a pump controller connected to the variable displacement pump. 6. (a) Supporting the first and second parts of the mold to move the parts into a spaced relationship to open the mold, and into a mating relationship to close the mold, and A tightening mechanism that strongly holds the mold in a closed state, and (b) a material that is connectable to the tightening mechanism and the mold, plasticizes a material, and injects a plasticized material into the mold, and is molded. An injection mechanism forming a part, (c) a fluid pressure operating device that is connected to at least one of the tightening mechanism and the injection mechanism and operates the same, and (d) is connected to the fluid pressure operating device and is predetermined. An electro-hydraulic actuation control device for supplying a hydraulic actuation fluid to the actuating device in response to the applied electric actuation signal; and Fluid pressure A variable discharge pump device for supplying a dynamic fluid to the electric-fluid pressure operation control device, and (G) (i) generating the drive signal according to predetermined molding parameters, sequenced operation and timed operation input, and (ii) required hydraulic fluid discharge Of the hydraulic working fluid required to be supplied by the variable displacement pump device during at least a portion of a particular phase of operation of the machine to obtain the programmed input without significantly exceeding the volume. An energy saving injection molding machine including a controller for generating the drive signal according to one of a number of stored values, each calculated according to a discharge rate. 7. A check valve device disposed between the variable displacement pump device and the electric-fluid pressure operation control device, and a check valve device of the electric-fluid pressure operation control device and the check valve device. The energy-saving injection molding machine of claim 6, further comprising an accumulator device disposed therebetween. 8. The energy-saving injection molding machine according to claim 6, wherein the variable speed motor device comprises a brushless DC motor. 9. The energy-saving injection molding machine of claim 6, wherein the variable speed motor system includes an AC motor. 10. The control device and the variable displacement pump device are connected to each other, and (i) the variable displacement pump device holds a pressure determined according to a pressure signal generated by the control device. Pressure guarantee mode that substantially supplies only the flow rate required for the above, and (ii) only the flow rate required for the variable displacement pump device to hold the flow amount determined according to the pressure signal from the control device. A flow rate guarantee mode that substantially supplies
The energy-saving injection molding machine of claim 9, further comprising a pump controller that selectively activates the pump device on at least one of: