CN116278114A - Synchronous hydraulic system of molding press and control method - Google Patents

Synchronous hydraulic system of molding press and control method Download PDF

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Publication number
CN116278114A
CN116278114A CN202310033746.1A CN202310033746A CN116278114A CN 116278114 A CN116278114 A CN 116278114A CN 202310033746 A CN202310033746 A CN 202310033746A CN 116278114 A CN116278114 A CN 116278114A
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China
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oil
hydraulic
communicated
cylinders
port
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CN202310033746.1A
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Inventor
秦付华
李龙杰
张冰
蒙翔龙
黄显富
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Liuzhou Wuling Automobile Industry Co Ltd
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Liuzhou Wuling Automobile Industry Co Ltd
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Priority to CN202310033746.1A priority Critical patent/CN116278114A/en
Publication of CN116278114A publication Critical patent/CN116278114A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B1/00—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen
    • B30B1/32—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by plungers under fluid pressure
    • B30B1/34—Presses, using a press ram, characterised by the features of the drive therefor, pressure being transmitted directly, or through simple thrust or tension members only, to the press ram or platen by plungers under fluid pressure involving a plurality of plungers acting on the platen
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/16—Control arrangements for fluid-driven presses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Presses (AREA)

Abstract

The invention discloses a synchronous hydraulic system of a molding press and a control method, wherein in the hydraulic system, a push rod of a hydraulic cylinder is connected with a pressing block of a mold, a first reversing valve can be switched between a first working position and a second working position, a first oil port of the first reversing valve is connected with an oil tank, a second oil port of the first reversing valve is communicated with a rodless cavity of an end hydraulic cylinder, a rod cavity of the second reversing valve is communicated with a third oil port through a hydraulic synchronous motor, a fourth oil port of the second reversing valve is communicated with the oil tank, and the second reversing valve can be switched to the third working position when the outlet pressure of a hydraulic oil pump reaches a preset value; the middle hydraulic cylinder is provided with a rod cavity communicated with the oil tank, the outlet of the hydraulic control one-way valve is communicated with the rodless cavity of the hydraulic cylinder, the inlet of the end hydraulic control one-way valve is communicated with the rodless cavity of the middle hydraulic cylinder, the inlet of the middle hydraulic control one-way valve is communicated with the oil tank, the sixth oil port is communicated with the control oil port of the end hydraulic control one-way valve, and the control oil port of the middle hydraulic control one-way valve is communicated with the third oil port. According to the invention, the hydraulic synchronous motor is additionally arranged to realize synchronous action of each hydraulic cylinder, so that the working pressing quality is improved.

Description

Synchronous hydraulic system of molding press and control method
Technical Field
The invention relates to the technical field of molding presses, in particular to a synchronous hydraulic system of a molding press and a control method.
Background
In many industrial articles, it is desirable to press one or more parts into a shape for use in an outer part, a structural part, or the like. The hydraulic system drives the oil cylinder to generate pushing force through pressure oil, and different working pressures are regulated through the overflow valve, so that the pushing force from small to large can be obtained, and the hydraulic press die can press workpieces with different requirements and different thicknesses.
The working principle of the four-cylinder hydraulic molding press which is relatively commonly used in the industry at present is as shown in figure 1:
the motor hydraulic pump is in a starting state, the electromagnet Y1 of the three-position four-way reversing valve 1' is electrified, so that the oil port P is communicated with the oil port B, the oil port A is communicated with the oil port T, pressure oil from the oil pump 2' enters the rodless cavities of the 4 oil cylinders 3' through the oil path from the oil port P to the oil port B of the three-position four-way reversing valve 1', the piston rod of the oil cylinder 3' is pushed to extend, the die pressing block moves downwards, and the workpiece 11 is pressed; meanwhile, hydraulic oil with a rod cavity of the oil cylinder 3' returns to the oil tank 4' through an oil path from an oil port A to an oil port T of the three-position four-way reversing valve 1 ';
the motor hydraulic pump is in a starting state, the electromagnet Y2 of the three-position four-way reversing valve 1' is electrified, the oil port P is communicated with the oil port A, the oil port B is communicated with the oil port T, pressure oil from the oil pump 2' enters rod cavities of 4 oil cylinders 3' through oil paths from the oil port P of the three-position four-way reversing valve 1' to the oil port A, a piston rod of the oil cylinder 3' is pushed to retract, and the die pressing block moves upwards to restore to a non-working state.
In the prior art, the phenomenon of asynchronous movement exists in the process of extending or retracting the piston rods of the 4 oil cylinders 3', the movement speed of the piston rods of some oil cylinders 3' is high, and the movement speed of the piston rods of some oil cylinders 3' is low, so that the following defects are caused:
(1) The die pressing block is in an inclined state when running up and down, one end of the die pressing block is in contact with a pressing workpiece, the other end of the die pressing block is not in contact with the pressing workpiece, and the pressing effect is difficult to meet the requirement.
(2) The die pressing block connects the piston rods of the 4 oil cylinders 3' into a whole, and each piston rod is mutually pulled, so that the sealing rings of the piston rods are easily damaged, and the oil leakage phenomenon occurs.
(3) The joint of the piston rod head of the oil cylinder 3' and the die pressing block is easy to crack and deform.
Disclosure of Invention
The invention aims to provide a synchronous hydraulic system and a control method of a die press, which ensure that two ends of a die press block can synchronously contact with a workpiece, ensure the pressing effect of the workpiece, ensure the reliability of the joint of a push rod of a hydraulic cylinder and the die press block, and improve the service lives of the hydraulic cylinders and the die press block.
In order to solve the technical problems, the invention provides a synchronous hydraulic system of a molding press, which comprises a first reversing valve, a second reversing valve, two hydraulic synchronous motors, more than two hydraulic control one-way valves and more than two hydraulic cylinders, wherein the hydraulic cylinders are sequentially distributed along the length direction of a mold pressing block, push rods of the hydraulic cylinders are connected with the mold pressing block,
the first reversing valve is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, at least provided with a first working position and a second working position, when the first reversing valve is positioned in the first working position, the first oil port and the second oil port are communicated, and the third oil port and the fourth oil port are communicated; when the hydraulic oil pump is positioned in the second working position, the first hydraulic oil port is communicated with the third hydraulic oil port, and the second hydraulic oil port is communicated with the fourth hydraulic oil port;
the first oil port is communicated with an oil tank through a hydraulic oil pump, the second oil port is communicated with rodless cavities of two hydraulic oil cylinders at the end part, rod cavities of the two hydraulic oil cylinders at the end part are communicated with a first port of the hydraulic synchronous motor in a one-to-one correspondence manner, the second port of the hydraulic synchronous motor is communicated with the third oil port after being collected, and the fourth oil port is communicated with the oil tank;
the second reversing valve is provided with a fifth oil port and a sixth oil port, and can be switched to a third working position when the outlet pressure of the hydraulic oil pump reaches a preset value, and when the second reversing valve is positioned in the third working position, the fifth oil port is communicated with the sixth oil port, and the fifth oil port is communicated with the oil tank through the hydraulic oil pump;
the hydraulic oil cylinders are more than three in number, except for the two hydraulic oil cylinders at the end parts, rod cavities of the hydraulic oil cylinders at the middle part are communicated with the oil tank, outlet ends of the hydraulic control one-way valves are communicated with rodless cavities of the hydraulic oil cylinders in a one-to-one correspondence mode, inlet ends of the two hydraulic control one-way valves at the end parts are communicated with rodless cavities of the hydraulic oil cylinders at the middle part, inlet ends of the hydraulic control one-way valves at the middle part are communicated with the oil tank, a sixth oil port is communicated with control oil ports of the hydraulic control one-way valves at the end parts, and control oil ports of the hydraulic control one-way valves at the middle part are communicated with the third oil port.
According to the synchronous hydraulic system of the die pressing machine, the two hydraulic synchronous motors are additionally arranged, the two hydraulic cylinders at the end part are controlled to synchronously act all the time, and the four hydraulic cylinders are controlled to synchronously press a workpiece only when the working pressure reaches a preset value, so that the two ends of a die pressing block can synchronously contact the pressed workpiece, the pressing quality of the workpiece is improved, meanwhile, the hydraulic cylinders synchronously act all the time, push rods of the hydraulic cylinders can be prevented from being pulled mutually, damage to sealing rings of the push rods is avoided, oil leakage is prevented, the reliability of the joint of the push rods of the hydraulic cylinders and a die pressing block is ensured, and the service lives of the hydraulic cylinders and the die pressing block are prolonged.
Optionally, the hydraulic oil pump further comprises a pressure switch and a controller, wherein the pressure switch is used for detecting the outlet pressure of the hydraulic oil pump, and the controller is electrically connected with the pressure switch, the first reversing valve and the second reversing valve.
Optionally, the hydraulic oil system further comprises a first oil way, a second oil way and a third oil way, wherein the first end of the first oil way is communicated with the second oil port, the second end of the first oil way is communicated with the second oil way and the first end of the third oil way, the second end of the second oil way and the second end of the third oil way are communicated with the rodless cavities of the two hydraulic oil cylinders in a one-to-one correspondence manner, and the pressure switch is arranged in the first oil way.
Optionally, the number of the hydraulic cylinders is more than three, and the hydraulic cylinder further comprises:
the first stop valve is arranged on an oil way between the second port and the third port of the hydraulic synchronous motor,
the second stop valve is arranged on the first oil path,
the third stop valve is arranged on an oil way between the sixth oil port and the control oil port of the two hydraulic control one-way valves at the end parts,
a fourth oil path and a fourth stop valve, wherein the first end of the fourth oil path is communicated with the second oil path/the third oil path, the second end of the third oil path is communicated with a rodless cavity of the hydraulic cylinder adjacent to the hydraulic cylinder at the corresponding end part, the fourth stop valve is arranged on the fourth oil path,
a fifth oil path and a fifth stop valve, wherein the fifth oil path is communicated with a rod cavity of the hydraulic cylinder adjacent to the hydraulic cylinder at the corresponding end part and one of the hydraulic synchronous motors, the hydraulic cylinder at the corresponding end part and the adjacent hydraulic cylinder are respectively communicated with one of the hydraulic synchronous motors correspondingly, the fifth stop valve is arranged on the fifth oil path,
a sixth stop valve arranged on an oil path between a rod cavity of the hydraulic cylinder at the other end part and a first port of the hydraulic synchronous motor correspondingly,
a seventh stop valve arranged on an oil path between the rodless cavity of the hydraulic cylinder at the other end part and the second oil port,
an eighth stop valve arranged on an oil path between a rodless cavity of the hydraulic cylinder adjacent to the hydraulic cylinder at the corresponding end and the oil tank,
a ninth stop valve arranged on an oil path between the rod cavity of each hydraulic cylinder in the middle and the oil tank,
and the tenth stop valve is arranged on an oil path between the inlet ends of the two hydraulic control one-way valves at the end parts.
Optionally, the first reversing valve is a three-position four-way reversing valve and is provided with a first electromagnet and a second electromagnet, when the first electromagnet is electrified, the first reversing valve is in a first working position, and when the second electromagnet is electrified, the first reversing valve is in a second working position.
Optionally, the second reversing valve is a two-position three-way reversing valve and is provided with a third electromagnet, and when the third electromagnet is electrified, the second reversing valve is in a third working position.
Optionally, the device further comprises an oil return filter and a cooler, wherein the oil return filter and the cooler are arranged on an oil path between the fourth oil port and the oil tank.
The invention also provides a control method of the synchronous hydraulic system of the molding press, when the pressing operation is required to be carried out on a longer workpiece, and four hydraulic cylinders are required to act simultaneously, the control method comprises the following steps:
the fourth stop valve and the fifth stop valve are controlled to be closed, the rest stop valves are opened, the hydraulic oil pump is controlled to be started, the first reversing valve is in a first working position, pressure oil from the hydraulic oil pump enters rodless cavities of the two hydraulic oil cylinders at the end part, push rods of the two hydraulic oil cylinders at the end part to extend out, the push rods of the two hydraulic oil cylinders at the middle part are driven to extend out synchronously, hydraulic oil in the rod cavities of the two hydraulic oil cylinders at the end part enters first ports of the two paths of hydraulic synchronous motors respectively to be synchronously controlled, and the hydraulic oil is collected and returns to an oil tank;
when the outlet pressure of the hydraulic oil pump reaches a preset value, controlling a second reversing valve to switch to a third working position, introducing pressure oil of rodless cavities of two hydraulic cylinders at the end parts into the rodless cavities of the hydraulic cylinders at the middle part, and simultaneously pressurizing the rodless cavities of the hydraulic cylinders to press a workpiece;
when the pressing is finished, controlling the first reversing valve to be in a second working position, enabling pressure oil from the hydraulic oil pump to enter second ports of the two hydraulic synchronous motors, enabling the pressure oil to enter rod cavities of the two hydraulic oil cylinders at the end parts after being synchronously controlled by the hydraulic synchronous motors, pushing push rods of the two hydraulic oil cylinders at the end parts to retract synchronously, enabling the push rods of the two hydraulic oil cylinders at the middle part to retract synchronously, and enabling hydraulic oil in the oil tank to be automatically supplemented to the rod cavities of the hydraulic oil cylinders at the middle part under the action of atmospheric pressure; hydraulic oil in the rodless cavity of each hydraulic oil cylinder returns to the oil tank.
According to the control method of the synchronous hydraulic system of the die press, the two hydraulic cylinders at the end parts are controlled to synchronously act all the time through the two hydraulic synchronous motors, and the four hydraulic cylinders are controlled to synchronously pressurize only when the working pressure reaches a preset value, so that the two ends of a die pressing block can synchronously contact with the pressed workpiece, the pressing quality of the workpiece is improved, meanwhile, the hydraulic cylinders synchronously act all the time, push rods of the hydraulic cylinders can be prevented from being pulled mutually, damage to sealing rings of the push rods is avoided, oil leakage is prevented, the reliability of the joint of the push rods of the hydraulic cylinders and the die pressing block is ensured, and the service lives of the hydraulic cylinders and the die pressing block are prolonged.
Optionally, when pressing operation is required to be performed on a shorter workpiece, two hydraulic cylinders are required to act simultaneously, the method comprises the following steps:
the method comprises the steps of controlling a first stop valve, a second stop valve, a fourth stop valve and a fifth stop valve to be opened, closing other stop valves, controlling the hydraulic oil pump to be started, enabling the first reversing valve to be in a first working position, enabling pressure oil from the hydraulic oil pump to enter a rodless cavity of one end part of the hydraulic oil cylinder and a rodless cavity of the adjacent hydraulic oil cylinder through the first reversing valve, and pushing push rods of the two hydraulic oil cylinders to extend; hydraulic oil with rod cavities of the two hydraulic cylinders respectively enter first ports of the two paths of hydraulic synchronous motors for synchronous control, and the hydraulic oil is collected and returned to the oil tank through the first reversing valve;
after the pressing is finished, the first reversing valve is controlled to be located at a second working position, pressure oil from the hydraulic oil pump enters the second ports of the two hydraulic synchronous motors through the first reversing valve to be synchronously controlled, then enters the rod cavity of one of the hydraulic cylinders at one end and the rod cavity of the adjacent hydraulic cylinder, pushes the push rods of the two hydraulic cylinders to synchronously retract, and hydraulic oil in the rodless cavities of the two hydraulic cylinders returns to the oil tank through the first reversing valve.
Drawings
FIG. 1 is a schematic diagram of a hydraulic system of a four-cylinder hydraulic press molding machine of the prior art;
FIG. 2 is a schematic diagram of a synchronous hydraulic system of a molding press provided by the invention;
FIG. 3 is a schematic diagram of the synchronous hydraulic system of the press of FIG. 2 when pressing a longer workpiece;
FIG. 4 is a schematic diagram of the synchronous hydraulic system of the press of FIG. 2 pressing a relatively short workpiece;
wherein reference numerals in fig. 1 are explained as follows:
a 1' -three-position four-way reversing valve; 2' -oil pump; 3' -cylinder;
wherein reference numerals in fig. 2-4 are illustrated as follows:
1-a first reversing valve; 2-a second reversing valve; 3-a hydraulic synchronous motor; 4-a hydraulic control one-way valve; 5-a hydraulic cylinder; 6-a hydraulic oil pump; 7-an oil tank; 8-a pressure switch; 91-a first oil path; 92-a second oil path; 93-a third oil path; 94-a fourth oil path; 95-a fifth oil path; 10-a first shut-off valve; 11-a second shut-off valve; 12-a third stop valve; 13-fourth shut-off valve; 14-a fifth shut-off valve; 15-a sixth shut-off valve; 16-seventh shut-off valve; 17-eighth shut-off valve; 18-a ninth shut-off valve; 19-tenth shut-off valve; 20-an oil return filter; 21-a cooler.
Detailed Description
In order to make the technical solution of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.
The terms "first," "second," and the like, herein are merely used for convenience in describing two or more structures or components that are identical or functionally similar, and do not denote any particular limitation of order and/or importance.
The term "plurality" as used herein refers to a plurality, typically two or more, of indefinite quantities; and when "a number" is used to denote the number of a certain number of components, the number of components is not necessarily related to each other.
Referring to fig. 2-4, fig. 2 is a schematic diagram of a synchronous hydraulic system of a molding press according to the present invention; FIG. 3 is a schematic diagram of the synchronous hydraulic system of the press of FIG. 2 when pressing a longer workpiece; fig. 4 is a schematic diagram of the synchronous hydraulic system of the press of fig. 2 when pressing a relatively short workpiece.
The invention provides a synchronous hydraulic system of a molding press, which comprises a first reversing valve 1, a second reversing valve 2, two hydraulic synchronous motors 3, four hydraulic control one-way valves 4 and four hydraulic cylinders 5, wherein the hydraulic cylinders 5 are sequentially distributed along the length direction of a mold pressing block, push rods of the hydraulic cylinders 5 are connected with the mold pressing block, and the synchronous hydraulic system comprises the following components:
the first reversing valve 1 is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, and is provided with at least a first working position and a second working position, when the first reversing valve is positioned in the first working position, the first oil port and the second oil port are communicated, and the third oil port and the fourth oil port are communicated; when the hydraulic oil pump is positioned at the second working position, the first hydraulic oil port is communicated with the third hydraulic oil port, and the second hydraulic oil port is communicated with the fourth hydraulic oil port;
the second reversing valve 2 is provided with a fifth oil port, a sixth oil port and a seventh oil port, and can be switched to a third working position when the pressure of hydraulic oil reaches a preset value, and the fifth oil port and the sixth oil port are communicated when the second reversing valve is positioned in the third working position;
the first oil port is communicated with the oil tank 7 through the hydraulic oil pump 6, the second oil port is communicated with rodless cavities of the two hydraulic oil cylinders 5 at the end part, the rod cavities of the two hydraulic oil cylinders 5 at the end part are communicated with a first port of the hydraulic synchronous motor 3 in a one-to-one correspondence manner, the second port of the hydraulic synchronous motor 3 is communicated with a third oil port after being converged, the fourth oil port is communicated with the oil tank 7, and the fifth oil port is communicated with the oil tank 7 through the hydraulic oil pump 6;
except for the two hydraulic cylinders 5 at the end parts, the rod cavities of the two hydraulic cylinders 5 at the middle part are communicated with the oil tank 7, the outlet ends of the hydraulic control check valves 4 are communicated with the rodless cavities of the hydraulic cylinders 5 in a one-to-one correspondence manner, the inlet ends of the two hydraulic control check valves 4 at the end parts are communicated with the rodless cavities of the hydraulic cylinders 5 at the middle part, the inlet ends of the hydraulic control check valves 4 at the middle part are communicated with the oil tank 7, the sixth oil port is communicated with the control oil ports of the two hydraulic control check valves 4 at the end parts, and the control oil ports of the hydraulic control check valves 4 at the middle part are communicated with the third oil port.
The synchronous hydraulic system of the molding press disclosed by the invention has the following working procedures when a workpiece is required to be pressed:
the hydraulic oil pump 6 is controlled to be in a starting state, the first reversing valve 1 is in a first working position, the first oil port and the second oil port are communicated, the third oil port and the fourth oil port are communicated, and pressure oil from the hydraulic oil pump 6 enters rodless cavities of two end hydraulic oil cylinders 5 through oil paths from the first oil port to the second oil port in the first reversing valve 1 to push rods of the two end hydraulic oil cylinders 5 to extend; meanwhile, as the push rods of the hydraulic cylinders 5 are connected with the die pressing block, the push rods of the two hydraulic cylinders 5 in the middle are driven to extend in a following way;
the hydraulic oil from the hydraulic oil pump 6 only enters the rodless cavities of the two hydraulic oil cylinders 5 at the end parts and does not enter the rodless cavities of the two hydraulic oil cylinders 5 at the middle part, the push rods of the two hydraulic oil cylinders 5 at the middle part extend to enable the rodless cavities to form vacuum, and the inlet ends of the hydraulic control check valves 4 at the middle part are communicated with the oil tank 7, so that under the action of atmospheric pressure, the hydraulic oil in the oil tank 7 enters the rodless cavities of the corresponding hydraulic oil cylinders 5 through the hydraulic control check valves 4 at the middle part to supplement oil; hydraulic oil with rod cavities of the two hydraulic cylinders 5 at the end part respectively enters a first port of the two paths of hydraulic synchronous motors 3 for synchronous control, and the hydraulic oil is collected and returned to the oil tank 7 through a right path from a third oil port to a fourth oil port in the first reversing valve 1; the hydraulic oil in the rod cavities of the two hydraulic cylinders 5 in the middle part is connected with an oil return tank 7 from another pipeline;
with the contact of the die pressing block and the workpiece, the anti-deformation force of the workpiece for bending resistance is gradually increased, the resistance of the working load is continuously increased, when the outlet pressure of the hydraulic oil pump 6 reaches a preset value, the second reversing valve 2 is switched to a third working position, the fifth oil port and the sixth oil port are communicated, as the fifth oil port is communicated with the oil tank 7 through the hydraulic oil pump 6, the sixth oil port is communicated with the control oil ports of the two hydraulic check valves 4 at the end, so that the pressure oil from the hydraulic oil pump 6 enters the control oil ports of the two hydraulic check valves 4 at the end through oil paths from the fifth oil port to the sixth oil port, the reverse oil path of the two hydraulic check valves 4 at the end is opened, and as the inlet ends of the two hydraulic check valves 4 at the end are communicated with the rodless cavities of the hydraulic oil cylinders 5 at the middle, the pressure oil entering the rodless cavities of the two hydraulic oil cylinders 5 at the end is introduced into the rodless cavities of the hydraulic oil cylinders 5 at the middle through the two hydraulic check valves 4 at the end, and the rodless cavities of the four oil cylinders are pressurized simultaneously to press the workpiece.
When the pressing is finished, the first reversing valve 1 is controlled to be positioned at a second working position, the first oil port is communicated with the third oil port, the second oil port and the fourth oil port are communicated, pressure oil from the hydraulic oil pump 6 enters the second ports of the two hydraulic synchronous motors 3 through oil paths from the first oil port to the third oil port in the first reversing valve 1, and after being controlled by the hydraulic synchronous motors 3, enters rod cavities of the two hydraulic oil cylinders 5 at the end parts from the first ports of the two hydraulic synchronous motors 3 respectively, and pushes push rods of the two hydraulic oil cylinders 5 at the end parts to retract synchronously; meanwhile, the push rods of the two middle hydraulic cylinders 5 are driven to retract, and the rod cavities of the two middle hydraulic cylinders 5 are communicated with the oil tank 7, so that oil is automatically replenished under the action of atmospheric pressure; hydraulic oil in rodless cavities of the two hydraulic cylinders 5 at the end part returns to the oil tank 7 through oil paths from the second oil port to the fourth oil port in the first reversing valve 1; and because the third oil port is also communicated with the control oil port of each hydraulic control one-way valve 4 in the middle, the pressure oil flowing out from the third oil port in the first reversing valve 1 also enters the control oil port of each hydraulic control one-way valve 4 in the middle, the reverse oil way of each hydraulic control one-way valve 4 in the middle is opened, and the hydraulic oil in the rodless cavities of the two hydraulic cylinders 5 in the middle returns to the oil tank 7 through the corresponding hydraulic control one-way valves 4.
Therefore, the synchronous hydraulic system of the die press is additionally provided with the two hydraulic synchronous motors 3, the two hydraulic cylinders 5 at the control end part always synchronously act, the four hydraulic cylinders 5 are controlled to synchronously pressurize only when the working pressure reaches a preset value, the workpiece is pressed, the two ends of the die pressing block can be ensured to synchronously contact with the pressed workpiece, the pressing quality of the workpiece is improved, meanwhile, the hydraulic cylinders 5 always synchronously act, push rods of the hydraulic cylinders 5 can be prevented from being mutually pulled, the damage to sealing rings of the push rods is avoided, the oil leakage phenomenon is prevented, the reliability of the joint of the push rods of the hydraulic cylinders 5 and the die pressing block is ensured, and the service life of the hydraulic cylinders 5 and the die pressing block is prolonged.
In this embodiment, the number of the hydraulic cylinders 5 is four, and in practical application, the number of the hydraulic cylinders 5 is not limited, for example, the number of the hydraulic cylinders 5 may be more than two, and may be adaptively adjusted according to the size of the workpiece.
Further, in this embodiment, the hydraulic oil pump further includes a pressure switch 8 and a controller, the pressure switch 8 is used for detecting the outlet pressure of the hydraulic oil pump 6, the controller is electrically connected with the pressure switch 8, the first reversing valve 1 and the second reversing valve 2, and the controller can control the second reversing valve 2 to switch to the third working position according to the outlet pressure of the hydraulic oil pump 6 detected by the pressure switch 8; the controller is also capable of controlling the first reversing valve 1 to switch between the first operating position and the second operating position in accordance with the pressing process.
As shown in fig. 2, the hydraulic control system further includes a first oil path 91, a second oil path 92 and a third oil path 93, wherein a first end of the first oil path 91 is communicated with the second oil port, a second end of the first oil path 91 is communicated with a first end of the second oil path 92 and a first end of the third oil path 93, a second end of the second oil path 92 and a second end of the third oil path 93 are communicated with rodless cavities of the two end hydraulic cylinders 5 in a one-to-one correspondence manner, and the pressure switch 8 is arranged on the first oil path 91.
Of course, the setting position of the pressure switch 8 is not limited, for example, the pressure switch 8 may also be disposed on the oil path between the first oil port and the hydraulic oil pump 6.
The first reversing valve 1 is a three-position four-way reversing valve and is provided with a first electromagnet and a second electromagnet, when the first electromagnet is electrified, the first reversing valve 1 is in a first working position, when the second electromagnet is electrified, the first reversing valve 1 is in a second working position, and the controller can control the first electromagnet or the second electromagnet to be electrified according to the pressing process so as to control the first reversing valve 1 to switch between the first working position and the second working position.
The second reversing valve 2 is a two-position three-way reversing valve and is provided with a third electromagnet and a control spring, and when the third electromagnet is electrified, the second reversing valve 2 is in a third working position.
Further, as can be seen from fig. 1, the four-cylinder hydraulic press molding machine in the prior art has a single function, only can operate four cylinders at the same time, and some workpieces are relatively short, and can not meet the requirements when only a short mold pressing block is installed on two cylinders for operation. Based on the above, in order to expand the application range of the synchronous hydraulic system of the molding press, and meet the pressing operation of shorter workpieces, the invention further comprises:
a first stop valve 10 arranged on an oil path between the second port and the third port of the hydraulic synchronous motor 3,
the second shutoff valve 11 is provided in the first oil passage 91,
a third stop valve 12 arranged on the oil path between the sixth oil port and the control oil port of the two hydraulic control one-way valves 4 at the end part,
a fourth oil passage 94 and a fourth shut-off valve 13, a first end of the fourth oil passage 94 communicates with the second oil passage 92/the third oil passage 93, a second end of the fourth oil passage 94 communicates with a rodless chamber of the hydraulic cylinder 5 adjacent to the corresponding end hydraulic cylinder 5, the fourth shut-off valve 13 is provided on the fourth oil passage 94,
a fifth oil path 95 and a fifth stop valve 14, the fifth oil path 95 is communicated with a rod cavity of the hydraulic cylinder 5 adjacent to the corresponding end hydraulic cylinder 5 and one of the hydraulic synchronous motors 3, the corresponding end hydraulic cylinder 5 and the adjacent hydraulic cylinder 5 are respectively communicated with one of the hydraulic synchronous motors 3, the fifth stop valve 14 is arranged on the fifth oil path 95,
a sixth stop valve 15 provided in an oil passage between the rod chamber of the hydraulic cylinder 5 at the other end and the first port of the corresponding hydraulic synchronous motor 3,
a seventh stop valve 16 arranged on the oil path between the rodless cavity of the hydraulic cylinder 5 at the other end and the second oil port,
an eighth stop valve 17 provided on an oil path between the rod chamber of the hydraulic cylinder 5 adjacent to the corresponding end portion hydraulic cylinder 5 and the oil tank 7,
a ninth stop valve 18 arranged on the oil path between the rod cavity of each hydraulic cylinder 5 in the middle and the oil tank 7,
the tenth stop valve 19 is disposed in the oil path between the inlet ends of the two pilot operated check valves 4.
Thus, when the pressing operation is required to be performed on a longer workpiece and four hydraulic cylinders 5 are required to act simultaneously, the fourth stop valve 13 and the fifth stop valve 14 are closed, and the rest stop valves are opened, so that the schematic diagram is simplified to facilitate understanding, on the basis of the schematic diagram of fig. 2, all the closed stop valves are in the disconnected state of the oil path branch, and the branch oil path is directly deleted; the hydraulic stop valve is replaced by a straight line when the opened stop valve is in an on state, the simplified hydraulic schematic diagram is shown in fig. 3, and the pressing process and the recovery process are as described above and are not repeated here.
When pressing operation is needed for shorter workpieces, only two hydraulic cylinders 5 are needed to act simultaneously, the first stop valve 10, the second stop valve 11, the fourth stop valve 13 and the fifth stop valve 14 are opened, the rest stop valves are closed, a simplified hydraulic schematic diagram is shown in fig. 4, and the working process when pressing the workpieces is as follows:
the hydraulic oil pump 6 is controlled to be in a starting state, the first reversing valve 1 is in a first working position, the first oil port and the second oil port are communicated, the third oil port and the fourth oil port are communicated, and pressure oil from the hydraulic oil pump 6 enters a rodless cavity of one end hydraulic oil cylinder 5 and a rodless cavity of the adjacent hydraulic oil cylinder 5 through an oil path from the first oil port to the second oil port in the first reversing valve 1 to push rods of the two hydraulic oil cylinders 5 to extend; simultaneously, hydraulic oil with rod cavities of the two hydraulic cylinders 5 respectively enter first ports of the two hydraulic synchronous motors 3 for synchronous control, and the hydraulic oil is collected and returned to the oil tank 7 through right paths from a third oil port to a fourth oil port in the first reversing valve 1.
When the pressing is finished, the first reversing valve 1 is controlled to be positioned at a second working position, the first oil port is communicated with the third oil port, the second oil port and the fourth oil port are communicated, pressure oil from the hydraulic oil pump 6 enters the second ports of the two hydraulic synchronous motors 3 through oil paths from the first oil port to the third oil port in the first reversing valve 1, and after being controlled by the hydraulic synchronous motors 3, enters rod cavities of one end hydraulic oil cylinder 5 and rod cavities of the adjacent hydraulic oil cylinders 5 from the first ports of the two hydraulic synchronous motors 3 respectively to push rods of the two hydraulic oil cylinders 5 to retract synchronously; meanwhile, hydraulic oil of rodless cavities of the two hydraulic cylinders 5 returns to the oil tank 7 through oil paths from the second oil port to the fourth oil port in the first reversing valve 1.
Therefore, the control functions of synchronous action of four oil cylinders and synchronous action of two oil cylinders can be realized by setting each stop valve to switch on and off the oil way, and the control system is suitable for pressing requirements of long workpieces and short workpieces, realizes multiple functions of one machine and expands the application range of the synchronous hydraulic system of the press molding machine.
With continued reference to fig. 2, the present invention further includes an oil return filter 20 and a cooler 21, where the oil return filter 20 and the cooler 21 are disposed on the oil path between the fourth oil port and the oil tank 7.
The invention also provides a control method of the synchronous hydraulic system of the molding press, when the pressing operation is required to be carried out on a longer workpiece and four hydraulic cylinders 5 are required to act simultaneously, the control method comprises the following steps:
the fourth stop valve 13 and the fifth stop valve 14 are controlled to be closed, the rest stop valves are opened, the hydraulic oil pump 6 is controlled to be started, the first reversing valve 1 is in a first working position, pressure oil from the hydraulic oil pump 6 enters rodless cavities of the two end hydraulic oil cylinders 5, push rods of the two end hydraulic oil cylinders 5 to extend, the push rods of the two middle hydraulic oil cylinders 5 are driven to extend synchronously, hydraulic oil in the rod cavities of the two end hydraulic oil cylinders 5 enters first ports of the two paths of hydraulic synchronous motors 3 respectively to be synchronously controlled, and the hydraulic oil is collected and then returns to the oil tank 7;
when the outlet pressure of the hydraulic oil pump 6 reaches a preset value, the second reversing valve 2 is controlled to be switched to a third working position, the pressure oil of the rodless cavities of the two hydraulic oil cylinders 5 at the end parts is introduced into the rodless cavities of the hydraulic oil cylinders 5 at the middle part, and the rodless cavities of the hydraulic oil cylinders 5 are pressurized simultaneously to press a workpiece;
when the pressing is finished, the first reversing valve 1 is controlled to be in a second working position, pressure oil from the hydraulic oil pump 6 enters the second ports of the two hydraulic synchronous motors 3, and after being synchronously controlled by the hydraulic synchronous motors 3, the pressure oil enters rod cavities of the two hydraulic oil cylinders 5 at the end parts respectively to push rods of the two hydraulic oil cylinders 5 at the end parts to synchronously retract, the push rods of the two hydraulic oil cylinders 5 at the middle part are driven to synchronously retract, and hydraulic oil in the oil tank 7 is automatically supplemented to the rod cavities of the hydraulic oil cylinders 5 at the middle part under the action of atmospheric pressure; the hydraulic oil in the rodless chamber of each hydraulic cylinder 5 returns to the oil tank 7.
According to the control method of the synchronous hydraulic system of the die press, the two hydraulic cylinders 5 at the end part are controlled to synchronously act all the time by the two hydraulic synchronous motors 3, and only when the working pressure reaches a preset value, the 4 hydraulic cylinders 5 are controlled to synchronously pressurize to press a workpiece, so that the two ends of a die pressing block can synchronously contact the pressed workpiece, the pressing quality of the workpiece is improved, meanwhile, the hydraulic cylinders 5 synchronously act all the time, push rods of the hydraulic cylinders 5 can be prevented from being pulled mutually, the damage to sealing rings of the push rods is avoided, the oil leakage phenomenon is prevented, the reliability of the joint of the push rods of the hydraulic cylinders 5 and the die pressing block is ensured, and the service lives of the hydraulic cylinders 5 and the die pressing block are prolonged.
Further, when pressing operation is required for a shorter workpiece, two hydraulic cylinders 5 are required to act simultaneously, the method comprises the following steps:
the first stop valve 10, the second stop valve 11, the fourth stop valve 13 and the fifth stop valve 14 are controlled to be opened, the rest stop valves are closed, the hydraulic oil pump 6 is controlled to be started, the first reversing valve 1 is positioned at a first working position, and pressure oil from the hydraulic oil pump 6 enters a rodless cavity of one end hydraulic oil cylinder 5 and a rodless cavity of the adjacent hydraulic oil cylinder 5 through the first reversing valve 1 to push rods of the two hydraulic oil cylinders 5 to extend; hydraulic oil with rod cavities of the two hydraulic cylinders 5 respectively enter first ports of the two paths of hydraulic synchronous motors 3 for synchronous control, and the hydraulic oil is collected and returned to the oil tank 7 through the first reversing valve 1;
when the pressing is finished, the first reversing valve 1 is controlled to be located at the second working position, pressure oil from the hydraulic oil pump 6 enters the second ports of the two hydraulic synchronous motors 3 through the first reversing valve 1 to be synchronously controlled, then enters the rod cavity of one end hydraulic oil cylinder 5 and the rod cavity of the adjacent hydraulic oil cylinder 5, pushes the push rods of the two hydraulic oil cylinders 5 to retract synchronously, and hydraulic oil in the rodless cavities of the two hydraulic oil cylinders 5 returns to the oil tank 7 through the first reversing valve 1.
Therefore, by arranging each stop valve to switch on and off the oil way, the hydraulic system has two control functions of synchronous action of four oil cylinders and synchronous action of two oil cylinders, is simultaneously suitable for pressing requirements of long workpieces and short workpieces, realizes multiple functions of one machine, and expands the application range of the synchronous hydraulic system of the press molding machine.
The above description of the synchronous hydraulic system and the control method of the molding press provided by the invention applies specific examples to illustrate the principle and the implementation of the invention, and the above examples are only used to help understand the method and the core idea of the invention. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.

Claims (9)

1. The synchronous hydraulic system of the molding press is characterized by comprising a first reversing valve (1), a second reversing valve (2), two hydraulic synchronous motors (3), more than two hydraulic control one-way valves (4) and more than two hydraulic cylinders (5), wherein the hydraulic cylinders (5) are sequentially distributed along the length direction of a mold pressing block, push rods of the hydraulic cylinders (5) are connected with the mold pressing block,
the first reversing valve (1) is provided with a first oil port, a second oil port, a third oil port and a fourth oil port, at least provided with a first working position and a second working position, when the first reversing valve is positioned in the first working position, the first oil port and the second oil port are communicated, and the third oil port and the fourth oil port are communicated; when the hydraulic oil pump is positioned in the second working position, the first hydraulic oil port is communicated with the third hydraulic oil port, and the second hydraulic oil port is communicated with the fourth hydraulic oil port;
the first oil port is communicated with an oil tank (7) through a hydraulic oil pump (6), the second oil port is communicated with rodless cavities of two hydraulic oil cylinders (5) at the end parts, the rod cavities of the two hydraulic oil cylinders (5) at the end parts are communicated with a first port of the hydraulic synchronous motor (3) in one-to-one correspondence, the second port of the hydraulic synchronous motor (3) is communicated with the third oil port after being collected, and the fourth oil port is communicated with the oil tank (7);
the second reversing valve (2) is provided with a fifth oil port and a sixth oil port, and can be switched to a third working position when the outlet pressure of the hydraulic oil pump (6) reaches a preset value, and when the second reversing valve is positioned in the third working position, the fifth oil port and the sixth oil port are communicated, and the fifth oil port is communicated with the oil tank (7) through the hydraulic oil pump (6);
the number of the hydraulic cylinders (5) is more than three, except for two hydraulic cylinders (5) at the end part, rod cavities of the hydraulic cylinders (5) at the middle part are communicated with the oil tank (7), outlet ends of the hydraulic control check valves (4) are communicated with rodless cavities of the hydraulic cylinders (5) in a one-to-one correspondence manner, inlet ends of the two hydraulic control check valves (4) are communicated with rodless cavities of the hydraulic cylinders (5) at the middle part, inlet ends of the hydraulic control check valves (4) at the middle part are communicated with the oil tank (7), a sixth oil port is communicated with control oil ports of the two hydraulic control check valves (4) at the end part, and control oil ports of the hydraulic control check valves (4) at the middle part are communicated with the third oil port.
2. The synchronous hydraulic system of a molding press according to claim 1, further comprising a pressure switch (8) and a controller, wherein the pressure switch (8) is used for detecting the outlet pressure of the hydraulic oil pump (6), and the controller is electrically connected with the pressure switch (8), the first reversing valve (1) and the second reversing valve (2).
3. The synchronous hydraulic system of a molding press according to claim 2, further comprising a first oil path (91), a second oil path (92) and a third oil path (93), wherein a first end of the first oil path (91) is communicated with the second oil port, a second end of the first oil path (91) is communicated with the second oil path (92) and a first end of the third oil path (93), a second end of the second oil path (92) and a second end of the third oil path (93) are communicated with rodless cavities of two end parts of the hydraulic cylinder (5) in one-to-one correspondence, and the pressure switch (8) is arranged on the first oil path (91).
4. A synchronous hydraulic system of a molding press according to claim 3, wherein the number of hydraulic cylinders (5) is three or more, further comprising:
a first stop valve (10) arranged on an oil path between the second port and the third port of the hydraulic synchronous motor (3),
a second shutoff valve (11) provided on the first oil passage (91),
a third stop valve (12) arranged on an oil path between the sixth oil port and the control oil ports of the two hydraulic control one-way valves (4) at the end parts,
a fourth oil passage (94) and a fourth stop valve (13), wherein a first end of the fourth oil passage (94) is communicated with the second oil passage (92)/the third oil passage (93), a second end of the third oil passage (93) is communicated with a rodless cavity of the hydraulic cylinder (5) adjacent to the hydraulic cylinder (5) at the corresponding end, the fourth stop valve (13) is arranged on the fourth oil passage (94),
a fifth oil path (95) and a fifth stop valve (14), wherein the fifth oil path (95) is communicated with a rod cavity of the hydraulic oil cylinder (5) adjacent to the hydraulic oil cylinder (5) at the corresponding end and one of the hydraulic synchronous motors (3), the hydraulic oil cylinder (5) at the corresponding end and the adjacent hydraulic oil cylinder (5) are respectively communicated with one of the hydraulic synchronous motors (3) correspondingly, the fifth stop valve (14) is arranged on the fifth oil path (95),
a sixth stop valve (15) arranged on an oil path between a rod cavity of the hydraulic cylinder (5) at the other end and a first port of the hydraulic synchronous motor (3) correspondingly,
a seventh stop valve (16) arranged on an oil path between the rodless cavity of the hydraulic cylinder (5) at the other end part and the second oil port,
an eighth stop valve (17) arranged on an oil path between a rod cavity of the hydraulic cylinder (5) adjacent to the hydraulic cylinder (5) at the corresponding end and the oil tank (7),
a ninth stop valve (18) arranged on an oil path between the rod cavity of each hydraulic cylinder (5) in the middle and the oil tank (7),
and a tenth stop valve (19) arranged on an oil path between the inlet ends of the two hydraulic control one-way valves (4).
5. The synchronous hydraulic system of a molding press according to any one of claims 1 to 4, wherein the first reversing valve (1) is a three-position four-way reversing valve and has a first electromagnet and a second electromagnet, the first reversing valve (1) is in a first working position when the first electromagnet is energized, and the first reversing valve (1) is in a second working position when the second electromagnet is energized.
6. The synchronous hydraulic system of a molding press according to any one of claims 1 to 4, characterized in that the second reversing valve (2) is a two-position three-way reversing valve and has a third electromagnet, the second reversing valve (2) being in a third working position when the third electromagnet is energized.
7. The synchronous hydraulic system of a molding press according to any one of claims 1-4, further comprising an oil return filter (20) and a cooler (21), wherein the oil return filter (20) and the cooler (21) are arranged on an oil path between the fourth oil port and the oil tank (7).
8. A control method of a synchronous hydraulic system of a molding press is characterized in that,
when the pressing operation is required to be performed on a longer workpiece and four hydraulic cylinders (5) are required to act simultaneously, the method comprises the following steps:
the fourth stop valve (13) and the fifth stop valve (14) are controlled to be closed, the rest stop valves are opened, the hydraulic oil pump (6) is controlled to be started, the first reversing valve (1) is positioned at a first working position, pressure oil from the hydraulic oil pump (6) enters rodless cavities of the two hydraulic oil cylinders (5) at the end part, push rods of the two hydraulic oil cylinders (5) at the end part to extend, the push rods of the two hydraulic oil cylinders (5) at the middle part are driven to extend synchronously, hydraulic oil in the rod cavities of the two hydraulic oil cylinders (5) at the end part enters first ports of the two hydraulic synchronous motors (3) respectively to be synchronously controlled, and the hydraulic oil is collected and then returns to the oil tank (7);
when the outlet pressure of the hydraulic oil pump (6) reaches a preset value, controlling the second reversing valve (2) to switch to a third working position, introducing pressure oil of rodless cavities of two end hydraulic oil cylinders (5) into rodless cavities of the middle hydraulic oil cylinders (5), and simultaneously pressurizing rodless cavities of the hydraulic oil cylinders (5) to press a workpiece;
after the pressing is finished, the first reversing valve (1) is controlled to be in a second working position, pressure oil from the hydraulic oil pump (6) enters second ports of the two hydraulic synchronous motors (3), after being synchronously controlled by the hydraulic synchronous motors (3), the pressure oil enters rod cavities of the two hydraulic oil cylinders (5) at the end parts respectively, push rods of the two hydraulic oil cylinders (5) at the end parts to retract synchronously, push rods of the two hydraulic oil cylinders (5) at the middle part are driven to retract synchronously, and hydraulic oil in the oil tank (7) is automatically supplemented to the rod cavities of the hydraulic oil cylinders (5) at the middle part under the action of atmospheric pressure; the hydraulic oil in the rodless cavity of each hydraulic oil cylinder (5) returns to the oil tank (7).
9. The method for controlling a synchronous hydraulic system of a molding machine according to claim 8, wherein,
when pressing operation is required to be performed on a shorter workpiece, and two hydraulic cylinders (5) are required to act simultaneously, the method comprises the following steps:
the method comprises the steps of controlling a first stop valve (10), a second stop valve (11), a fourth stop valve (13) and a fifth stop valve (14) to be opened, closing the rest stop valves, controlling the hydraulic oil pump (6) to be started, enabling the first reversing valve (1) to be in a first working position, enabling pressure oil from the hydraulic oil pump (6) to enter a rodless cavity of one end part of the hydraulic oil cylinder (5) and a rodless cavity of the adjacent hydraulic oil cylinder (5) through the first reversing valve (1), and pushing push rods of the two hydraulic oil cylinders (5) to extend; hydraulic oil with rod cavities of the two hydraulic cylinders (5) respectively enter first ports of the two hydraulic synchronous motors (3) to be synchronously controlled, and the hydraulic oil is collected and then returns to the oil tank (7) through the first reversing valve (1);
after the pressing is finished, the first reversing valve (1) is controlled to be located at a second working position, pressure oil from the hydraulic oil pump (6) enters the second ports of the two hydraulic synchronous motors (3) through the first reversing valve (1) to be synchronously controlled, then enters one end of the second reversing valve, is provided with a rod cavity of the hydraulic oil cylinder (5) and a rod cavity of the adjacent hydraulic oil cylinder (5), pushes the push rods of the two hydraulic oil cylinders (5) to synchronously retract, and hydraulic oil in the rodless cavities of the two hydraulic oil cylinders (5) returns to the oil tank (7) through the first reversing valve (1).
CN202310033746.1A 2023-01-10 2023-01-10 Synchronous hydraulic system of molding press and control method Pending CN116278114A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310033746.1A CN116278114A (en) 2023-01-10 2023-01-10 Synchronous hydraulic system of molding press and control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310033746.1A CN116278114A (en) 2023-01-10 2023-01-10 Synchronous hydraulic system of molding press and control method

Publications (1)

Publication Number Publication Date
CN116278114A true CN116278114A (en) 2023-06-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310033746.1A Pending CN116278114A (en) 2023-01-10 2023-01-10 Synchronous hydraulic system of molding press and control method

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Country Link
CN (1) CN116278114A (en)

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