CN116393674A - Die casting machine, electrohydraulic control system for pressure closed-loop control and control method thereof - Google Patents
Die casting machine, electrohydraulic control system for pressure closed-loop control and control method thereof Download PDFInfo
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- CN116393674A CN116393674A CN202310059335.XA CN202310059335A CN116393674A CN 116393674 A CN116393674 A CN 116393674A CN 202310059335 A CN202310059335 A CN 202310059335A CN 116393674 A CN116393674 A CN 116393674A
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- 238000004512 die casting Methods 0.000 title claims abstract description 23
- 238000000034 method Methods 0.000 title claims abstract description 21
- 238000002347 injection Methods 0.000 claims abstract description 106
- 239000007924 injection Substances 0.000 claims abstract description 106
- 238000004146 energy storage Methods 0.000 claims abstract description 30
- 238000001514 detection method Methods 0.000 claims abstract description 17
- 239000012530 fluid Substances 0.000 claims description 9
- XOFYZVNMUHMLCC-ZPOLXVRWSA-N prednisone Chemical compound O=C1C=C[C@]2(C)[C@H]3C(=O)C[C@](C)([C@@](CC4)(O)C(=O)CO)[C@@H]4[C@@H]3CCC2=C1 XOFYZVNMUHMLCC-ZPOLXVRWSA-N 0.000 claims description 2
- 238000005266 casting Methods 0.000 abstract description 16
- 239000003921 oil Substances 0.000 description 58
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 14
- 229910052757 nitrogen Inorganic materials 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 230000001105 regulatory effect Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000010729 system oil Substances 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/32—Controlling equipment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/2015—Means for forcing the molten metal into the die
- B22D17/2023—Nozzles or shot sleeves
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
The invention discloses a die casting machine, a pressure closed-loop control electrohydraulic control system and a control method thereof, wherein the die casting machine comprises the pressure closed-loop control electrohydraulic control system and the control method thereof, the pressure closed-loop control electrohydraulic control system comprises a control device, an energy storage device, a booster cylinder and a injection cylinder which are connected through pipelines, and an outlet of the booster cylinder is connected with an outlet throttle valve; an inlet pressure sensor is connected to a pipeline of the injection oil cylinder inlet; the pressurizing oil cylinder is used for driving the injection oil cylinder to move; the control device is electrically connected with the outlet throttle valve and the inlet pressure sensor, receives a pressure detection signal of the inlet pressure sensor and controls the opening degree of the outlet throttle valve. The invention aims to realize the control of casting pressure in real time and improve the accuracy of pressure control without manual operation.
Description
Technical Field
The invention relates to the field of die casting machines, in particular to an electrohydraulic control system for closed-loop control of pressure of a die casting machine and a control method thereof.
Background
At present, the traditional die casting machine is used for casting pressure by manually filling and discharging nitrogen into and from an energy accumulator, so that manual adjustment of the nitrogen pressure is realized, the accuracy of pressure control is low, and the casting pressure cannot be set and controlled at will.
Disclosure of Invention
The invention mainly aims to provide an electrohydraulic control system for pressure closed-loop control, which aims to realize the control of casting pressure in real time and improve the accuracy of pressure control without manual operation.
In order to achieve the above object, the present invention provides an electrohydraulic control system for closed-loop control of pressure, which is applied to a die casting machine, and includes:
the device comprises a control device, an energy storage device, a booster cylinder and a injection cylinder, wherein the energy storage device, the booster cylinder and the injection cylinder are connected through pipelines, and an outlet of the booster cylinder is connected with an outlet throttle valve;
an inlet pressure sensor is connected to a pipeline at the inlet of the injection cylinder;
the pressurizing oil cylinder is used for pressurizing the injection oil cylinder;
the control device is electrically connected with the outlet throttle valve and the inlet pressure sensor, receives a pressure detection signal of the inlet pressure sensor and controls the opening degree of the outlet throttle valve.
In an embodiment, the electrohydraulic control system for pressure closed-loop control further comprises an inlet throttle valve, the inlet throttle valve is connected to a pipeline between an outlet of the energy storage device and an inlet of the booster cylinder, the control device is electrically connected with the inlet throttle valve, and the control device receives a pressure detection signal of the inlet pressure sensor and controls the inlet throttle valve to work.
In an embodiment, the electrohydraulic control system for pressure closed-loop control further comprises a throttle valve, the throttle valve is connected to a pipeline of the inlet throttle valve and the inlet of the booster cylinder, and the control device is electrically connected with the throttle valve.
In an embodiment, the electrohydraulic control system for pressure closed-loop control further comprises a proportional valve, the proportional valve is connected to a pipeline between the outlet of the energy storage device and the inlet of the booster cylinder, and the control device is electrically connected with the proportional valve.
In one embodiment, the electrohydraulic control system of pressure closed loop control further comprises a control valve device connected to a pipeline between the energy storage device and the booster cylinder.
In an embodiment, the injection cylinder comprises an injection cylinder inlet, an injection piston rod and an injection cylinder outlet which are sequentially arranged, the injection piston rod moves back and forth between the injection cylinder inlet and the injection cylinder outlet to generate a pressure value, the inlet pressure sensor is used for detecting the inlet pressure value of the injection cylinder, and the control device controls the opening of the valve port of the outlet throttle valve according to the difference value between the inlet pressure value and the outlet pressure value of the injection cylinder and the target pressure value set by the injection cylinder.
In an embodiment, the injection cylinder further comprises a hammer head and an injection piston which are respectively connected with the injection piston rod, the injection piston is used for driving the injection piston rod to move, and the injection piston rod is used for driving the hammer head to move.
In an embodiment, outlet pressure sensors are connected to the pipelines of the outlets of the injection cylinder and the booster cylinder, the control device is electrically connected with the outlet pressure sensors, and the control device receives pressure detection signals of the outlet pressure sensors and controls the throttle inlet valve and the throttle outlet valve to work.
The invention also comprises a die casting machine comprising a pressure closed-loop controlled electrohydraulic control system, the pressure closed-loop controlled electrohydraulic control system comprising: the device comprises a control device, an energy storage device, a booster cylinder and a injection cylinder, wherein the energy storage device, the booster cylinder and the injection cylinder are connected through pipelines, and an outlet of the booster cylinder is connected with an outlet throttle valve; inlet pressure sensors are connected to the pipelines of the injection oil cylinder and the booster oil cylinder inlet; the pressurizing oil cylinder is used for driving the injection oil cylinder to move; the control device is electrically connected with the outlet throttle valve and the inlet pressure sensor, receives a pressure detection signal of the inlet pressure sensor and controls the opening degree of the outlet throttle valve.
The invention also provides an electrohydraulic control method for pressure closed-loop control, wherein the control method comprises the following steps:
setting the set pressure of the oil pressure in the electrohydraulic system controlled by the pressure closed loop, and setting the set duration;
obtaining the measured pressure of the oil pressure and obtaining the measured duration;
when the actual measured pressure reaches the set pressure, and the required actual measured time length reaches the set time length, the control device receives a signal and controls the outlet throttle valve to be closed.
In one embodiment, determining whether the pressure of the oil pressure is in a hysteresis state according to a time difference Δt between the set time period and the measured time period;
the control device controls the opening degree of the outlet throttle valve based on the state of the pressure of the oil pressure, and adjusts the pressure of the oil pressure to a set pressure.
In one embodiment, when the pressure of the oil pressure is in a lag state, the control device controls the opening degree of the outlet throttle, and controls the flow rate of the fluid by adjusting the opening size of the outlet throttle so as to adjust the pressure of the oil pressure;
when the measured time length reaches the set time length, the measured pressure of the oil pressure reaches the set pressure, and the control device receives a signal and controls the outlet throttle valve to be closed;
when the set time period and the measured time period have a time difference Δt, the control device 10 returns to execution to determine whether the pressure of the oil pressure is in a hysteresis state;
when the pressure of the oil pressure is not in a hysteresis state, the control device obtains a deviation value delta E between the set pressure and the measured pressure, controls the opening degree of the outlet throttle valve, and controls the flow rate of fluid to adjust the pressure of the oil pressure by adjusting the opening size of the outlet throttle valve;
when the measured time length reaches the set time length, the measured pressure of the oil pressure reaches the set pressure, and the control device receives a signal and controls the outlet throttle valve to be closed;
when the set time length and the measured time length are different by delta T, the control device returns to execute to judge whether the pressure of the oil pressure is in a hysteresis state or not.
According to the technical scheme, the electrohydraulic control system for pressure closed-loop control can realize control of the pressure of each oil cylinder under the condition that the energy storage device is not required to be manually charged with and discharged from nitrogen, and after the pressure closed-loop control is realized, nitrogen resources can be saved on one hand, the operation difficulty of workers can be reduced on the other hand, the complex process of castings can be realized, and the manufacture of complex castings can be completed.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of an embodiment of an electro-hydraulic control system for closed-loop control of pressure in accordance with the present invention;
FIG. 2 is a schematic diagram of a further embodiment of the pressure closed-loop control electro-hydraulic control system of the present invention;
FIG. 3 is a schematic flow chart of the electrohydraulic control method of the present invention for pressure closed loop control.
Reference numerals illustrate:
| reference numerals | Name of the name | Reference numerals | Name of the |
| 10 | |
20 | |
| 30 | |
40 | |
| 50 | |
60 | |
| 70 | |
80 | |
| 90 | |
100 | |
| 110 | Outlet pressure sensor |
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, if a directional indication (such as up, down, left, right, front, and rear … …) is involved in the embodiment of the present invention, the directional indication is merely used to explain the relative positional relationship, movement condition, etc. between the components in a specific posture, and if the specific posture is changed, the directional indication is correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if "and/or" and/or "are used throughout, the meaning includes three parallel schemes, for example," a and/or B "including a scheme, or B scheme, or a scheme where a and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The invention provides an electrohydraulic control system for pressure closed-loop control.
Referring to fig. 1 to 2, in an embodiment of the present invention, an electrohydraulic control system for closed-loop control of pressure is applied to a die casting machine, and includes:
the device comprises a control device 10, an energy storage device 20, a booster cylinder 30 and a injection cylinder 40 which are connected through pipelines, wherein an outlet of the booster cylinder 30 is connected with an outlet throttle valve 50;
an inlet pressure sensor 60 is connected to a pipeline at the inlet of the injection cylinder 40;
the booster cylinder 30 is used for boosting the injection cylinder 40;
the control device 10 is electrically connected to the meter-out valve 50 and the inlet pressure sensor 60, and the control device 10 receives a pressure detection signal from the inlet pressure sensor 60 and controls the opening degree of the meter-out valve 50.
The invention provides an electrohydraulic control system applied to pressure closed-loop control of a die casting machine, an energy storage device 20 can carry out energy release and energy storage actions, a power source for forward injection movement of an injection cylinder 40 is provided, the die casting machine can reach a rodless cavity of a booster cylinder 30 by releasing high-pressure oil in the energy storage device 20, the pressure of the rodless cavity of the injection cylinder 40 is further improved by the action of the booster cylinder 30, thereby realizing pressurization of the injection cylinder 40, the injection cylinder 40 comprises a piston rod and an injection head, the injection head is fixedly connected with the piston rod, the high-pressure oil is pushed to a die cavity to complete die casting according to a certain speed and pressure under the action of the booster cylinder 30, after the pressurization process is triggered, the control device 10 receives a pressure detection signal of the inlet pressure cylinder 40, the opening of a valve port of an outlet throttle valve 50 is regulated and controlled in real time by the pressure detection signal, when the inlet pressure of the injection cylinder 40 is excessively large, the valve port of the outlet throttle valve 50 is opened, the valve port of the outlet throttle valve 50 is reduced, the pressure of the cylinder is reduced, the pressure is stably controlled to be reduced in the vicinity of the pressure of the booster cylinder 30 along with the pressure of the pressure in the booster cylinder 30, the pressure is stably reduced along with the pressure in the pressure of the booster cylinder 30, the pressure in the vicinity of the pressure valve 30, the pressure is stably reduced along with the pressure in the pressure of the booster cylinder 30, the pressure in the pressure valve 30 is stably reduced along with the pressure of the pressure in the pressure valve 30, and the pressure of the pressure valve 30 is stably reduced, the design can realize the control of casting pressure in real time and improve the accuracy of pressure control without manual operation, namely the pressure in the injection oil cylinder 40 and the pressure boosting oil cylinder 30 can be accurately controlled, and the control of the pressure of each oil cylinder can be realized without manually charging and discharging nitrogen to the energy storage device 20, so that after the closed-loop control of the pressure is realized, nitrogen resources can be saved on one hand, the operation difficulty of workers can be reduced on the other hand, the complex process of castings can be realized, and the manufacture of complex castings can be completed.
In the embodiment of the present invention, the outlet throttle 50 may be any one of a single proportional valve, a single servo valve, a single proportional servo valve, and a valve group with a throttle function formed by combining a plurality of proportional valves, servo valves, or proportional servo valves.
In the embodiment of the invention, an inlet pressure sensor is connected to a pipeline of the inlet of the booster cylinder.
Referring to fig. 1-2, in the embodiment of the present invention, the electrohydraulic control system for pressure closed-loop control further includes an inlet throttle valve 70, the inlet throttle valve 70 is connected to a pipeline between the outlet of the energy storage device 20 and the inlet of the booster cylinder 30, the control device 10 is electrically connected to the inlet throttle valve 70, and the control device 10 receives a pressure detection signal of the inlet pressure sensor 60 and controls the operation of the inlet throttle valve 70.
When the injection is started, the inlet throttle valve 70 is opened, the control device 10 receives a pressure detection signal of the inlet pressure sensor 60, the opening of a valve port of the inlet throttle valve 70 is regulated and controlled in real time through the pressure detection signal, so that the speed of high-pressure oil in the energy storage device 20 entering the booster cylinder 30 is controlled through the opening of the inlet throttle valve 70, the injection cylinder 40 is influenced by the flow rate of the high-pressure oil in the booster cylinder 30, when the inlet pressure of the injection cylinder 40 is overlarge, the inlet throttle valve 70 and the outlet throttle valve 50 can be simultaneously opened, the pressure in the injection cylinder 40 can be well reduced, the control of the pressure of each cylinder can be realized under the condition that nitrogen is not manually charged and discharged to the energy storage device 20, and the pressure of the injection cylinder 40 and the booster cylinder 30 can be accurately controlled through regulating the outlet throttle valve 50 and the inlet throttle valve 70.
In the embodiment of the present invention, the inlet throttle 70 may be any one of a single manual throttle, a single proportional reversing valve, and a valve group with a throttle control function formed by combining multiple manual throttles, proportional throttles, or proportional reversing valves.
Referring to fig. 1-2, in the embodiment of the present invention, the electrohydraulic control system for pressure closed-loop control further includes a throttle valve 80, the throttle valve 80 is connected to the pipeline of the inlet throttle valve 70 and the inlet of the booster cylinder 30, and the control device 10 is electrically connected to the throttle valve 80.
Referring to fig. 1 to 2, in the embodiment of the present invention, the electrohydraulic control system for pressure closed-loop control further includes a proportional valve 90, the proportional valve 90 is connected to a pipeline between the outlet of the energy storage device 20 and the inlet of the booster cylinder 30, and the control device 10 is electrically connected to the proportional valve 90.
The throttle valve is a valve for controlling the fluid flow by changing the throttle section or the throttle length, if the valve is opened more, the fluid flow is more, and if the valve is opened more, the fluid flow is less, and the throttle valve 80 is further arranged, so that the high-pressure oil flowing to the booster cylinder 40 of the energy storage device 20 can be better regulated.
In the embodiment of the present invention, the throttle valve 80 may be any one of a single manual throttle valve, a single proportional reversing valve, and a valve group with a throttle control function formed by combining multiple manual throttle valves, proportional throttle valves, or proportional reversing valves.
Referring to fig. 1-2, in the embodiment of the present invention, the electrohydraulic control system for closed-loop control of pressure further includes a control valve device 100, where the control valve device 100 is connected to a pipeline between the energy storage device 20 and the booster cylinder 30.
By providing the control valve device 100, the flow rate of the high-pressure oil in the energy storage device 20 into the booster cylinder 30 can be controlled further.
In an embodiment of the present invention, the control valve device 100 includes a check valve. The control valve device 100 is a one-way valve, and avoids the phenomenon of backflow and the like of high-pressure oil in the booster cylinder 30.
The check valve can be any one form of a single pipe type check valve, a single plate type check valve, a single plug-in type check valve, or a valve group with a check valve control function formed by combining a plurality of pipe type check valves, plate type check valves or plug-in type check valves.
Referring to fig. 1-2, in the embodiment of the present invention, the control valve device 100 is connected to the line between the accumulator 20 and the meter-in valve 70.
Referring to fig. 1 to 2, in the embodiment of the present invention, the control valve device 100 is connected to a line between the meter-in valve 70 and the booster cylinder 30.
Referring to fig. 1 to 2, in the embodiment of the present invention, the injection cylinder 40 includes an injection cylinder inlet, an injection piston rod, and an injection cylinder outlet that are sequentially disposed, the injection piston rod moves back and forth between the injection cylinder inlet and the injection cylinder outlet to generate a pressure value, the inlet pressure sensor 60 is configured to detect the inlet pressure value of the injection cylinder, and the control device controls the opening of the valve port of the outlet throttle valve 50 according to the difference between the inlet pressure value and the outlet pressure value of the injection cylinder 40 and the target pressure value set by the injection cylinder.
After the real-time pressure of the inlet of the injection cylinder 40 and the outlet of the injection cylinder 40 is obtained, the opening of the valve port of the outlet throttle 50 is adjusted in real time to change the flow quantity of high-pressure oil, so that the pressure in the injection cylinder 40 and the pressure in the booster cylinder 30 is controlled, the closed-loop control adjustment of the pressure is realized, the casting pressure reaches a pressure set value, and the continuous and accurate control of the casting pressure is realized.
Referring to fig. 1 to 2, in the embodiment of the present invention, the injection cylinder 40 further includes a hammer head and an injection piston respectively connected to the injection piston rod, where the injection piston is used to drive the injection piston rod to move, and the injection piston rod is used to drive the hammer head to move.
In the movement process of the injection piston driving the injection piston rod, the injection piston rod is used for driving the hammer head to generate real-time pressure on the inlet and the outlet of the injection cylinder 40, after the control device obtains the real-time pressure on the inlet of the injection cylinder 40 and the outlet of the injection cylinder 40, the opening of the valve port of the outlet throttle valve 50 is adjusted in real time to change the flow rate of high-pressure oil, so that the control of the pressure in the injection cylinder 40 and the booster cylinder 30 is realized, the closed-loop control adjustment of the pressure is realized, the casting pressure reaches the pressure set value, and the continuous and accurate control of the casting pressure is realized.
Specifically, the inlet pressure sensor 60 detects an inlet pressure Pi of the injection cylinder 40, and an outlet pressure value of the injection cylinder 40 is P0;
wherein, the diameter Dc of the injection piston, the diameter Dc of the injection piston rod and the diameter dp of the hammer head are cast to pressure;
setting the casting pressure of the electrohydraulic control system controlled by the pressure closed loop to Pzr, wherein E is the difference E= Pzr-PZ; based on the value of E, the control device 10 controls the states of opening and closing of the ports of the meter-in valve 70 and the meter-out valve 50.
Specifically, the control device obtains a corresponding voltage control signal through the pressure detection signal, and controls the opening of the valve port of the outlet throttle valve through the voltage control signal.
In the embodiment of the invention, the control voltage of the electrohydraulic control system for pressure closed-loop control
(where K_p is the scaling factor and K_I is the integration factor).
In the pressurizing control stage, the opening of the outlet throttle valve 50 is controlled by the control voltage, in the process, the real-time pressure of the inlet of the injection cylinder 40 and the outlet of the injection cylinder 40 is obtained, the control voltage is adjusted in real time according to the real-time pressure, and the opening of the outlet throttle valve 50 is adjusted according to the adjusted control voltage, so that the casting pressure of the die casting machine reaches a pressure set value, and continuous and accurate control of the casting pressure is realized.
Referring to fig. 1 to 2, in the embodiment of the present invention, an outlet pressure sensor 110 is connected to the outlet pipes of the injection cylinder 40 and the booster cylinder 30, the control device 10 is electrically connected to the outlet pressure sensor 110, and the control device 10 receives a pressure detection signal of the outlet pressure sensor 90 and controls the operation of the inlet throttle valve 70 and the outlet throttle valve 50.
The outlet pressure sensor 110 is provided for detecting the oil pressure P0 after the charging of the energy storage device 20 is completed in real time, and the pressure at the outlet of the injection cylinder 40 is detected by the outlet pressure sensor 110, so that the opening degree of the valve port of the outlet throttle valve 50 is regulated and controlled in real time by a detection signal, and the control of the pressure in the injection cylinder 40 and the booster cylinder 30 is realized.
In an embodiment of the present invention, the inlet pressure sensor 60 and the outlet pressure sensor 110 may be diaphragm pressure sensors.
The diaphragm pressure sensor is suitable for closed occasions because the isolating diaphragm contacts with a medium in a large area; in particular to a viscous or pasty medium and a highly corrosive liquid or a medium rich in particles, which is convenient to install and is convenient to be applied to mass production, thereby reducing the production cost.
The invention also provides a die casting machine, which comprises a pressure closed-loop control electrohydraulic control system, wherein the pressure closed-loop control electrohydraulic control system comprises: the device comprises a control device 10, an energy storage device 20, a booster cylinder 30 and a injection cylinder 40 which are connected through pipelines, wherein an outlet of the booster cylinder 30 is connected with an outlet throttle valve 50; inlet pressure sensors 60 are connected to the pipelines of the inlets of the injection cylinder 40 and the booster cylinder 30; the booster cylinder 30 is used for driving the injection cylinder 40 to move; the control device 10 is electrically connected to the meter-out valve 50 and the inlet pressure sensor 60, and the control device 10 receives a pressure detection signal from the inlet pressure sensor 60 and controls the opening degree of the meter-out valve 50.
The invention also provides a die casting machine which comprises an electrohydraulic control system for pressure closed-loop control, and because the die casting machine adopts all the technical schemes of all the embodiments, the die casting machine also has all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted.
Referring to fig. 3, fig. 3 is a schematic flow chart of an embodiment of an electrohydraulic control method for pressure closed-loop control according to the present invention. The method is applied to the die casting machine with the electrohydraulic system with the pressure closed-loop control, wherein the control method comprises the following steps:
setting the set pressure of the oil pressure in the electrohydraulic system controlled by the pressure closed loop, and setting the set duration;
obtaining the measured pressure of the oil pressure and obtaining the measured duration;
when the measured pressure reaches the set pressure, the control device 10 receives a signal and controls to close the meter-out valve 50 when the desired measured time period reaches the set time period.
In the embodiment of the invention, in the stage of starting the supercharging operation, when the measured pressure of the oil pressure in the electrohydraulic system controlled by the pressure closed loop reaches the set pressure of the oil pressure in the electrohydraulic system controlled by the pressure closed loop, the set pressure value is specifically a reference value of a target value for operation regulation and control of the electrohydraulic system controlled by the pressure closed loop in a preset corresponding mode. The different modes correspond to different reference values, specifically, in the pressurizing process, the pressure of a rodless cavity of a pressurizing oil cylinder 30 in an electrohydraulic system controlled by a pressure closed loop is communicated with an energy storage device 20 and a pressurizing oil cylinder 40, the opening of an outlet throttle valve 50 is maintained at a larger position, the back pressure of a rod cavity of the pressurizing oil cylinder 30 is rapidly reduced, the pressure value of the rodless cavity of the pressurizing oil cylinder 30 after pressurizing is increased along with the reduction of the back pressure, so that the pressure value of the rodless cavity of the pressurizing oil cylinder 30 is approaching, when the actual measured pressure reaches the set pressure, the outlet throttle valve 50 is closed, thereby the control of the pressure of each oil cylinder can be realized without human, the accurate control of the pressure of the pressurizing oil cylinder 40 and the pressurizing oil cylinder 30 can be realized, the set pressure control can be linearly increased, the pressurizing pressure of the die casting machine can be ensured to be stably set, and the pressurizing pressure and the pressure setting time can be set in multiple sections, and the closed loop real-time control can be realized.
In the embodiment of the invention, whether the pressure of the oil pressure is in a hysteresis state is judged according to the time difference delta T between the set time length and the actually measured time length;
the control device 10 controls the opening degree of the meter-out valve 50 based on the state of the pressure of the oil pressure, and adjusts the pressure of the oil pressure to a set pressure.
In the stage where the supercharging operation is started, since the opening through the meter-out valve 50 is maintained at a large position, so that approach, specifically, when the system sets the set pressure, two phenomena occur due to the difference in the closing time of the meter-out valve 50 and the difference in the system characteristics: 1. the same proportional integral coefficient is adopted, and when the pressure setting is smaller, the overshoot is larger; 2. as the pressure setting becomes smaller, the longer the check valve closing time becomes, and the longer the delay time for the pressure to rise becomes, so that it is possible to determine whether the pressure of the oil pressure is at the set pressure or not and whether the pressure of the system oil pressure is in the delay state or not by the difference in the time for which the meter-out valve 50 is closed. Specifically, in an embodiment, different proportional integral coefficients may be used for different pressure settings, where the higher the pressure setting, the greater the proportional integral coefficient value, where the pressure setting is at a maximum value, such as 330bar, the proportional coefficient is set to 0.4, and the integral coefficient is set to 0.1; when the pressure is set to a minimum value, such as 200bar, the proportionality coefficient is set to 0.2 and the integral coefficient is set to 0.08; when the pressure is set in the range, setting a proportional coefficient and an integral parameter in a difference mode; solves the problem of overshoot. In an embodiment, for the special image that the delay time of the pressure rise is longer when the pressure setting is low, feedforward control is adopted, that is, when the pressure setting is low, in a control strategy, the proportionality coefficient at the moment is properly lifted to a higher value, for example, the proportionality coefficient is operated for a period of time such as 10ms and then is restored to a normal setting value, so that the closing time of the one-way valve is shortened, the delay of the pressure rise is quickly eliminated, and the problem of overlong delay time is solved.
In the embodiment of the present invention, when the pressure of the oil pressure is in a hysteresis state, the control device 10 controls the opening of the meter-out valve 50, and controls the flow rate of the fluid by adjusting the opening size of the meter-out valve 50 so as to adjust the pressure of the oil pressure;
when the measured time period reaches the set time period, the measured pressure of the oil pressure reaches the set pressure, and the control device 10 receives a signal and controls the outlet throttle 50 to be closed;
when the set time period and the measured time period have a time difference Δt, the control device 10 returns to execution to determine whether the pressure of the oil pressure is in a hysteresis state;
when the pressure of the oil pressure is not in a hysteresis state, the control device 10 obtains a deviation value deltae between the set pressure and the measured pressure, the control device 10 controls the opening degree of the outlet throttle valve 50, and the flow rate of the fluid is controlled by adjusting the opening size of the outlet throttle valve 50 so as to adjust the pressure of the oil pressure;
when the measured time period reaches the set time period, the measured pressure of the oil pressure reaches the set pressure, and the control device 10 receives a signal and controls the outlet throttle 50 to be closed;
when the set time period and the measured time period have a time difference Δt, the control device 10 returns to execution to determine whether the pressure of the oil pressure is in a hysteresis state.
In this embodiment, the opening of the outlet throttle 50 is maintained at a larger position, so that the pressure of each cylinder can be controlled without any human being by the control method, and the pressure in the injection cylinder 40 and the booster cylinder 30 can be accurately controlled.
The foregoing description is only of the preferred embodiments of the present invention and is not intended to limit the scope of the invention, and all equivalent structural changes made by the description of the present invention and the accompanying drawings or direct/indirect application in other related technical fields are included in the scope of the invention.
Claims (12)
1. An electrohydraulic control system for closed-loop control of pressure, applied to a die casting machine, comprising:
the device comprises a control device, an energy storage device, a booster cylinder and a injection cylinder, wherein the energy storage device, the booster cylinder and the injection cylinder are connected through pipelines, and an outlet of the booster cylinder is connected with an outlet throttle valve;
an inlet pressure sensor is connected to a pipeline at the inlet of the injection cylinder;
the pressurizing oil cylinder is used for pressurizing the injection oil cylinder;
the control device is electrically connected with the outlet throttle valve and the inlet pressure sensor, receives a pressure detection signal of the inlet pressure sensor and controls the opening degree of the outlet throttle valve.
2. The pressure closed-loop control electro-hydraulic control system according to claim 1, further comprising an inlet throttle valve, wherein the inlet throttle valve is connected to a pipeline between an outlet of the energy storage device and an inlet of the booster cylinder, the control device is electrically connected to the inlet throttle valve, and the control device receives a pressure detection signal of the inlet pressure sensor and controls the inlet throttle valve to operate.
3. The pressure closed-loop controlled electro-hydraulic control system according to claim 2, further comprising a throttle valve, wherein the throttle valve is connected to a pipeline between the inlet throttle valve and the inlet of the booster cylinder, and the control device is electrically connected to the throttle valve.
4. The pressure closed-loop control electro-hydraulic control system according to claim 2, further comprising a proportional valve, wherein the proportional valve is connected to a pipeline between the outlet of the energy storage device and the inlet of the booster cylinder, and the control device is electrically connected to the proportional valve.
5. The pressure closed-loop controlled electro-hydraulic control system of claim 1, further comprising a control valve device coupled to a line between the energy storage device and the boost cylinder.
6. The electro-hydraulic control system of pressure closed-loop control according to claim 1, wherein the injection cylinder comprises an injection cylinder inlet, an injection piston rod and an injection cylinder outlet which are sequentially arranged, the injection piston rod moves back and forth between the injection cylinder inlet and the injection cylinder outlet to generate a pressure value, the inlet pressure sensor is used for detecting the inlet pressure value of the injection cylinder, and the control device controls the opening of the valve port of the outlet throttle valve according to the difference value between the inlet pressure value and the outlet pressure value of the injection cylinder and the target pressure value set by the injection cylinder.
7. The electro-hydraulic control system of claim 6, wherein the injection cylinder further comprises a hammer head and an injection piston respectively connected with the injection piston rod, the injection piston is used for driving the injection piston rod to move, and the injection piston rod is used for driving the hammer head to move.
8. The electrohydraulic control system of claim 1 wherein said injection and said boost cylinder are coupled to an outlet pressure sensor in a conduit, said control being electrically coupled to said outlet pressure sensor, said control receiving a pressure sensing signal from said outlet pressure sensor and controlling said inlet throttle to operate with said outlet throttle.
9. A die casting machine, comprising: a pressure closed-loop controlled electro-hydraulic control system as claimed in any one of claims 1 to 8.
10. An electrohydraulic control method for pressure closed-loop control, which is applied to a die casting machine, is characterized by comprising the following steps:
setting the set pressure of the oil pressure in the electrohydraulic system controlled by the pressure closed loop, and setting the set duration;
obtaining the measured pressure of the oil pressure and obtaining the measured duration;
and when the required measured time length reaches the set time length, the control device receives a signal and controls the outlet throttle valve to be closed.
11. The method of electrohydraulic control of a closed-loop control of a pressure of claim 10, wherein,
judging whether the pressure of the oil pressure is in a hysteresis state or not according to a time difference delta T between the set time length and the actually measured time length;
the control device controls the opening degree of the outlet throttle valve based on the state of the pressure of the oil pressure, and adjusts the pressure of the oil pressure to a set pressure.
12. The method of electrohydraulic control of a closed-loop control of a pressure of claim 11, wherein said controlling means further comprises a control unit,
when the pressure of the oil pressure is in a hysteresis state, the control device controls the opening degree of the outlet throttle valve, and controls the flow rate of fluid to adjust the pressure of the oil pressure by adjusting the opening size of the outlet throttle valve;
when the measured time length reaches the set time length, the control device receives a signal and controls the outlet throttle valve to be closed;
when the set time period and the measured time period have a time difference Δt, the control device 10 returns to execution to determine whether the pressure of the oil pressure is in a hysteresis state;
when the pressure of the oil pressure is not in a hysteresis state, the control device obtains a deviation value delta E between the set pressure and the measured pressure, controls the opening degree of the outlet throttle valve, and controls the flow rate of fluid to adjust the pressure of the oil pressure by adjusting the opening size of the outlet throttle valve;
when the measured time length reaches the set time length, the control device receives a signal and controls the outlet throttle valve to be closed;
when the set time length and the measured time length are different by delta T, the control device returns to execute to judge whether the pressure of the oil pressure is in a hysteresis state or not.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310059335.XA CN116393674A (en) | 2023-01-16 | 2023-01-16 | Die casting machine, electrohydraulic control system for pressure closed-loop control and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310059335.XA CN116393674A (en) | 2023-01-16 | 2023-01-16 | Die casting machine, electrohydraulic control system for pressure closed-loop control and control method thereof |
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| CN116393674A true CN116393674A (en) | 2023-07-07 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310059335.XA Pending CN116393674A (en) | 2023-01-16 | 2023-01-16 | Die casting machine, electrohydraulic control system for pressure closed-loop control and control method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116944463A (en) * | 2023-09-20 | 2023-10-27 | 江苏德优镁轻合金科技有限公司 | Discharging device for casting machine |
-
2023
- 2023-01-16 CN CN202310059335.XA patent/CN116393674A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116944463A (en) * | 2023-09-20 | 2023-10-27 | 江苏德优镁轻合金科技有限公司 | Discharging device for casting machine |
| CN116944463B (en) * | 2023-09-20 | 2023-12-15 | 江苏德优镁轻合金科技有限公司 | Discharging device for casting machine |
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