A press machine synchronous hydraulic system and control method

Abstract

The application discloses a press mould machine synchronous hydraulic system and a control method. In the hydraulic system, the push rod of a hydraulic oil cylinder is connected with a mould pressing block, a first reversing valve can be switched between a first working position and a second working position, the first oil port of the first reversing valve is connected with an oil tank, the second oil port is communicated with the rodless cavity of an end hydraulic oil cylinder, the rod cavity is communicated with a third oil port through a hydraulic synchronous motor, and the fourth oil port is communicated with the oil tank. The second reversing valve can be switched to a third working position when the outlet pressure of a hydraulic oil pump reaches a preset value. The rod cavity of a middle hydraulic oil cylinder is communicated with the oil tank, the outlet of a hydraulic control check valve is communicated with the rodless cavity of the hydraulic oil cylinder, the inlet of an end hydraulic control check valve is communicated with the rodless cavity of the middle hydraulic oil cylinder, the inlet of a middle hydraulic control check valve is communicated with the oil tank, the sixth oil port is communicated with the control oil port of the end hydraulic control check valve, and the control oil port of the middle hydraulic control check valve is communicated with the third oil port. The hydraulic synchronous motor is additionally arranged to realize the synchronous action of the hydraulic oil cylinders, and the working pressing quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compression molding machine, in particular to a compression molding machine synchronous hydraulic system and control method. BACKGROUND

[0002] In many industrial products, it is necessary to press one or more parts into a certain shape for appearance parts, structural parts, etc. The hydraulic system drives the oil cylinder to generate pushing force through pressure oil, adjusts different working pressures through overflow valve, and can obtain pushing force from small to large, so that the hydraulic compression molding machine can press workpieces of different requirements and thicknesses.

[0003] The four-oil-cylinder hydraulic compression molding machine commonly used in the industry at present, as shown in the figure, its working principle is: Figure 1 The motor hydraulic pump is in the starting state, the electromagnet Y1 of the three-position four-way reversing valve 1' is electrified, so that the oil port P is connected with the oil port B, and the oil port A is connected with the oil port T. The pressure oil from the oil pump 2' enters the four oil cylinders 3' through the oil port P to the oil port B of the three-position four-way reversing valve 1', and the piston rod of the oil cylinder 3' is pushed out, the mold pressing block moves downward, and the workpiece 11 is pressed; at the same time, the hydraulic oil in the rod cavity of the oil cylinder 3' returns to the oil tank 4' through the oil port A to the oil port T of the three-position four-way reversing valve 1';

[0004] The motor hydraulic pump is in the starting state, the electromagnet Y2 of the three-position four-way reversing valve 1' is electrified, so that the oil port P is connected with the oil port A, and the oil port B is connected with the oil port T. The pressure oil from the oil pump 2' enters the four oil cylinders 3' through the oil port P to the oil port A of the three-position four-way reversing valve 1', and the piston rod of the oil cylinder 3' is pushed back, the mold pressing block moves upward to restore to the non-working state.

[0005] The four oil cylinders 3' of the prior art, the piston rod is extended or retracted, and there is a phenomenon of different step movements. Some oil cylinders 3' move fast, and some oil cylinders 3' move slowly, resulting in the following defects:

[0006] (1) The mold pressing block is in an inclined state when moving up and down, one end has contacted the pressed workpiece, and the other end has not, so the pressing effect is difficult to meet the requirements.

[0007] (2) The mold pressing block connects the piston rods of the four oil cylinders 3' as a whole, and the piston rods pull each other, which easily damages the sealing ring of the piston rod and causes oil leakage.

[0008] (3) The connection between the piston rod head of the oil cylinder 3' and the mold pressing block is easy to crack and deform.

[0009] SUMMARY

[0010] ​The present application aims to provide a press mold machine synchronous hydraulic system and control method, which can ensure that the two ends of the mold pressing block can be in contact with the workpiece synchronously, ensure the pressing effect of the workpiece, ensure the reliability of the connection between the push rod of the hydraulic cylinder and the mold pressing block, and improve the service life of the hydraulic cylinder and the mold pressing block.

[0011] To solve the above technical problems, the present application provides a press mold machine synchronous hydraulic system, which comprises a first reversing valve, a second reversing valve, two hydraulic synchronous motors, two or more hydraulic control check valves, and two or more hydraulic cylinders.

[0012] The first reversing valve has a first oil port, a second oil port, a third oil port and a fourth oil port, and at least a first working position and a second working position.

[0013] The first oil port is communicated with the oil tank through a hydraulic oil pump, the second oil port is communicated with the rodless cavity of the two end hydraulic cylinders, the rod cavity of the two end hydraulic cylinders is one-to-one communicated with the first port of the hydraulic synchronous motor, the second port of the hydraulic synchronous motor is communicated with the third oil port after being gathered, and the fourth oil port is communicated with the oil tank.

[0014] The second reversing valve has 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.

[0015] The number of the hydraulic cylinders is three or more, the rod cavity of each middle hydraulic cylinder is communicated with the oil tank, the outlet end of the hydraulic control check valve is one-to-one communicated with the rodless cavity of the hydraulic cylinder, the inlet end of the two end hydraulic control check valves is communicated with the rodless cavity of each middle hydraulic cylinder, the inlet end of each middle hydraulic control check valve is communicated with the oil tank, the sixth oil port is communicated with the control oil port of the two end hydraulic control check valves, and the control oil port of each middle hydraulic control check valve is communicated with the third oil port.

[0016] The synchronous hydraulic system of the die press machine is provided with two hydraulic synchronous motors, the two hydraulic oil cylinders at the end are always controlled to move synchronously, only when the working pressure reaches the preset value, the four hydraulic oil cylinders are controlled to press synchronously, the workpiece is pressed, the two ends of the die block can synchronously contact and press the workpiece, the pressing quality of the workpiece is improved, meanwhile, the hydraulic oil cylinders always move synchronously, the push rods of the hydraulic oil cylinders are prevented from being pulled by each other, the sealing ring of the push rod is prevented from being damaged, the oil leakage is prevented, the reliability of the connection between the push rod of the hydraulic oil cylinder and the die block is ensured, and the service life of the hydraulic oil cylinder and the die block is improved.

[0017] Optionally, 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.

[0018] Optionally, the first oil path, the second oil path and the third oil path are further included, the first end of the first oil path is communicated with the second oil port, the second end of the first oil path is communicated with the first end of the second oil path and the third oil path, the second end of the second oil path and the third oil path is communicated with the rodless cavity of the two hydraulic oil cylinders at the end one by one, and the pressure switch is arranged on the first oil path.

[0019] Optionally, the number of the hydraulic oil cylinders is more than three, and the hydraulic system further includes:

[0020] a first stop valve arranged on the oil path between the second port of the hydraulic synchronous motor and the third oil port,

[0021] a second stop valve arranged on the first oil path,

[0022] a third stop valve arranged on the oil path between the sixth oil port and the control oil port of the two hydraulic control check valves at the end,

[0023] a fourth oil path and a fourth stop valve, the first end of the fourth oil path is communicated with the second oil path / third oil path, the second end of the third oil path is communicated with the rodless cavity of the hydraulic oil cylinder adjacent to the corresponding end hydraulic oil cylinder, and the fourth stop valve is arranged on the fourth oil path,

[0024] a fifth oil path and a fifth stop valve, the fifth oil path is communicated with the rod cavity of the hydraulic oil cylinder adjacent to the corresponding end hydraulic oil cylinder and one of the hydraulic synchronous motors, the corresponding end hydraulic oil cylinder and the adjacent hydraulic oil cylinder are respectively communicated with one of the hydraulic synchronous motors, and the fifth stop valve is arranged on the fifth oil path,

[0025] A sixth stop valve is arranged on an oil path between a rod cavity of the hydraulic cylinder at the other end and a first port of the hydraulic synchronous motor corresponding thereto,

[0026] A seventh stop valve is arranged on an oil path between a rodless cavity of the hydraulic cylinder at the other end and the second oil port,

[0027] An eighth stop valve is arranged on an oil path between a rodless cavity of the hydraulic cylinder adjacent to the corresponding end of the hydraulic cylinder and the oil tank,

[0028] A ninth stop valve is arranged on an oil path between a rod cavity of each of the hydraulic cylinders at the middle and the oil tank,

[0029] A tenth stop valve is arranged on an oil path between the inlet ends of the two hydraulic control check valves at the ends.

[0030] Optionally, the first reversing valve is a three-position four-way reversing valve, and has a first electromagnet and a second electromagnet, when the first electromagnet is energized, the first reversing valve is in a first working position, and when the second electromagnet is energized, the first reversing valve is in a second working position.

[0031] Optionally, the second reversing valve is a two-position three-way reversing valve, and has a third electromagnet, when the third electromagnet is energized, the second reversing valve is in a third working position.

[0032] Optionally, further comprising an oil return filter and a cooler, the oil return filter and the cooler are arranged on an oil path between the fourth oil port and the oil tank.

[0033] The application also provides a control method of the synchronous hydraulic system of the press machine, when it is needed to perform a pressing operation on a long workpiece, and four hydraulic cylinders need to act simultaneously, the method comprises the following steps:

[0034] The fourth stop valve and the fifth stop valve are controlled to be closed, the remaining stop valves are all opened, the hydraulic oil pump is controlled to be started, and the first reversing valve is in the first working position, pressure oil from the hydraulic oil pump enters the rodless cavities of the two hydraulic cylinders at the ends, and pushes the push rods of the two hydraulic cylinders at the ends to extend, the push rods of the two hydraulic cylinders at the middle are driven to extend synchronously, the hydraulic oil in the rod cavities of the two hydraulic cylinders at the ends respectively enters the first ports of two hydraulic synchronous motors for synchronous control, and the hydraulic oil is collected and returned to the oil tank;

[0035] When the outlet pressure of the hydraulic oil pump reaches a preset value, the second reversing valve is controlled to be switched to the third working position, the pressure oil in the rodless cavities of the two hydraulic cylinders at the ends is introduced into the rodless cavities of the hydraulic cylinders at the middle, and the rodless cavities of the hydraulic cylinders are simultaneously pressurized to perform pressing on the workpiece;

[0036] When the pressing is completed, the first reversing valve is controlled to be in the second working position, the pressure oil from the hydraulic oil pump enters the second ports of the two hydraulic synchronous motors, is synchronously controlled by the hydraulic synchronous motors, and then enters the rod cavities of the two end hydraulic oil cylinders respectively, so that the push rods of the two end hydraulic oil cylinders are synchronously retracted, the push rods of the two middle hydraulic oil cylinders are synchronously retracted, and the hydraulic oil in the oil tank is automatically supplemented to the rod cavities of the middle hydraulic oil cylinders under the action of atmospheric pressure; the hydraulic oil in the rodless cavities of the hydraulic oil cylinders returns to the oil tank.

[0037] The control method of the synchronous hydraulic system of the die press machine can ensure that the two end hydraulic oil cylinders are always synchronously operated by the two hydraulic synchronous motors, and only when the working pressure reaches the preset value, the four hydraulic oil cylinders are synchronously pressurized to press the workpiece, so that the two ends of the die block can synchronously contact and press the workpiece, the pressing quality of the workpiece is improved, the push rods of the hydraulic oil cylinders are always synchronously operated, the push rods of the hydraulic oil cylinders are prevented from being pulled by each other, the sealing ring of the push rod is prevented from being damaged, the oil leakage phenomenon is prevented, the reliability of the connection between the push rod of the hydraulic oil cylinder and the die block is ensured, and the service life of the hydraulic oil cylinder and the die block is improved.

[0038] Optionally, when it is necessary to perform the pressing operation on a shorter workpiece, and it is necessary to simultaneously operate the two hydraulic oil cylinders, the following steps are included:

[0039] The first stop valve, the second stop valve, the fourth stop valve and the fifth stop valve are controlled to be opened, the remaining stop valves are closed, the hydraulic oil pump is controlled to be started, and the first reversing valve is in the first working position, the pressure oil from the hydraulic oil pump enters the rodless cavities of one end hydraulic oil cylinder and an adjacent hydraulic oil cylinder through the first reversing valve, and pushes the push rods of the two hydraulic oil cylinders to extend; the hydraulic oil in the rod cavities of the two hydraulic oil cylinders enters the first ports of two hydraulic synchronous motors respectively for synchronous control, and then is returned to the oil tank through the first reversing valve after the hydraulic oil is collected;

[0040] When the pressing is completed, the first reversing valve is controlled to be in the second working position, the pressure oil from the hydraulic oil pump enters the second ports of the two hydraulic synchronous motors for synchronous control through the first reversing valve, and then enters the rod cavities of one end hydraulic oil cylinder and an adjacent hydraulic oil cylinder, so that the push rods of the two hydraulic oil cylinders are synchronously retracted, and the hydraulic oil in the rodless cavities of the two hydraulic oil cylinders is returned to the oil tank through the first reversing valve. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 It is a structural schematic view of the hydraulic system of the prior art four-oil-cylinder hydraulic die press machine;

[0042] Figure 2 The schematic diagram of the synchronous hydraulic system of the molding machine provided by the present invention;

[0043] Figure 3 for Figure 2 A schematic diagram of the principle of the synchronous hydraulic system of the die press when pressing a long workpiece;

[0044] Figure 4 for Figure 2 A simplified diagram of the principle of the synchronous hydraulic system of the die press when pressing a shorter workpiece;

[0045] in, Figure 1 The reference numerals in the figures are described as follows:

[0046] 1'-3-position four-way reversing valve; 2'-oil pump; 3'-oil cylinder;

[0047] in, Figures 2-4 The reference numerals in the figures are described as follows:

[0048] 1-First reversing valve; 2-Second reversing valve; 3-Hydraulic synchronous motor; 4-Hydraulic-controlled one-way valve; 5-Hydraulic cylinder; 6-Hydraulic oil pump; 7-Oil tank; 8-Pressure switch; 91-First oil circuit; 92-Second oil circuit; 93-Third oil circuit; 94-Fourth oil circuit; 95-Fifth oil circuit; 10-First stop valve; 11-Second stop valve; 12-Third stop valve; 13-Fourth stop valve; 14-Fifth stop valve; 15-Sixth stop valve; 16-Seventh stop valve; 17-Eighth stop valve; 18-Ninth stop valve; 19-Tenth stop valve; 20-Return oil filter; 21-Cooler. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The words "first", "second", etc. mentioned in this article are only used to facilitate the description of two or more structures or components with the same or similar structures and / or functions, and do not mean any special limitation on the order and / or importance.

[0051] The term "several" as used herein refers to an indefinite number of multiple components, usually more than two; and when "several" is used to indicate the number of certain components, it does not indicate the quantitative relationship between these components.

[0052] Please refer to Figures 2-4 , Figure 2 The schematic diagram of the synchronous hydraulic system of the molding machine provided by the present invention; Figure 3 for Figure 2 A schematic diagram of the principle of the synchronous hydraulic system of the die press when pressing a long workpiece;Figure 4 For Figure 2 The principle diagram of the synchronous hydraulic system of the compression molding machine is used for pressing the short workpiece.

[0053] The present application provides a kind of synchronous hydraulic system of compression molding machine, including first reversing valve 1, second reversing valve 2, two hydraulic synchronous motors 3, four hydraulic control check valves 4 and four hydraulic cylinders 5, each hydraulic cylinder 5 is sequentially distributed along the length direction of mould pressing block, the push rod of each hydraulic cylinder 5 is connected with the mould pressing block, wherein:

[0054] First reversing valve 1 has first oil port, second oil port, third oil port and fourth oil port, and at least has first working position and second working position, when being located in first working position, first oil port and second oil port are communicated, third oil port and fourth oil port are communicated;When being located in second working position, first oil port and third oil port are communicated, second oil port and fourth oil port are communicated;

[0055] Second reversing valve 2 has fifth oil port, sixth oil port and seventh oil port, and can be switched to third working position when the pressure of hydraulic oil reaches preset value, when being located in third working position, fifth oil port and sixth oil port are communicated;

[0056] First oil port is communicated with oil tank 7 by hydraulic oil pump 6, second oil port is communicated with rodless cavity of two hydraulic cylinders 5 at end, rod cavity of two hydraulic cylinders 5 at end is communicated with first port of hydraulic synchronous motor 3 in one-to-one correspondence, second port of hydraulic synchronous motor 3 is communicated with third oil port after being converged, fourth oil port is communicated with oil tank 7, fifth oil port is communicated with oil tank 7 by hydraulic oil pump 6;

[0057] Except two hydraulic cylinders 5 at end, rod cavity of two hydraulic cylinders 5 in middle is communicated with oil tank 7, outlet end of hydraulic control check valve 4 is communicated with rodless cavity of hydraulic cylinder 5 in one-to-one correspondence, inlet end of two hydraulic control check valves 4 at end is communicated with rodless cavity of each hydraulic cylinder 5 in middle, inlet end of each hydraulic control check valve 4 in middle is communicated with oil tank 7, sixth oil port is communicated with control oil port of two hydraulic control check valves 4 at end, control oil port of each hydraulic control check valve 4 in middle is communicated with third oil port.

[0058] The working process of the synchronous hydraulic system of compression molding machine when needing to press workpiece is as follows:

[0059] Control hydraulic oil pump 6 to be in starting state, first reversing valve 1 is in first working position, first oil port and second oil port are communicated, third oil port and fourth oil port are communicated, pressure oil from hydraulic oil pump 6 enters the rodless cavity of two hydraulic cylinders 5 at end through the oil path of first oil port to second oil port in first reversing valve 1, and pushes the push rod of two hydraulic cylinders 5 at end to stretch out;At the same time, since the push rod of each hydraulic cylinder 5 is connected with mould pressing block, therefore, the push rod of two hydraulic cylinders 5 in middle is also driven to stretch out following;

[0060] Since the pressure oil from the hydraulic oil pump 6 only enters the rodless chambers of the two hydraulic cylinders 5 at the end, and does not enter the rodless chambers of the two hydraulic cylinders 5 in the middle, the extension of the push rods of the two hydraulic cylinders 5 in the middle will form a vacuum in their rodless chambers. Moreover, since the inlet ends of the hydraulically controlled one-way valves 4 in the middle are connected to the oil tank 7, under the action of atmospheric pressure, the hydraulically controlled one-way valves 4 in the middle are opened, and the hydraulic oil in the oil tank 7 enters the rodless chamber of the corresponding hydraulic cylinder 5 through the hydraulically controlled one-way valves 4 in the middle for oil replenishment; the hydraulic oil in the rod chambers of the two hydraulic cylinders 5 at the end respectively enters the first ports of the two-way hydraulic synchronous motors 3 for synchronous control, and after the hydraulic oil is collected, it returns to the oil tank 7 through the right path from the third oil port to the fourth oil port in the first reversing valve 1; the hydraulic oil in the rod chambers of the two hydraulic cylinders 5 in the middle is connected back to the oil tank 7 from another pipeline;

[0061] As the mold pressing block contacts the workpiece, the anti-deformation force of the workpiece against compression bending gradually increases, and the resistance of the workload continues to increase. When the outlet pressure of the hydraulic oil pump 6 reaches the preset value, the second reversing valve 2 switches to the third working position, and the fifth oil port and the sixth oil port are connected. Since the fifth oil port is connected to the oil tank 7 through the hydraulic oil pump 6, and the sixth oil port is connected to the control oil ports of the two hydraulically controlled one-way valves 4 at the end, the pressure oil from the hydraulic oil pump 6 will enter the control oil ports of the two hydraulically controlled one-way valves 4 at the end through the oil path from the fifth oil port to the sixth oil port, opening the reverse oil path of the two hydraulically controlled one-way valves 4 at the end. Since the inlet ends of the two hydraulically controlled one-way valves 4 at the end are connected to the rodless cavities of the middle hydraulic cylinders 5, the pressure oil entering the rodless cavities of the two hydraulic cylinders 5 at the end is introduced into the rodless cavities of the middle hydraulic cylinders 5 through the two hydraulically controlled one-way valves 4 at the end. From then on, the rodless cavities of the four cylinders are pressurized at the same time to press the workpiece.

[0062] When the pressing is completed, the first reversing valve 1 is controlled to be in the second working position, the first oil port is connected to the third oil port, the second oil port is connected to the fourth oil port, and the pressure oil from the hydraulic oil pump 6 enters the second port of the two hydraulic synchronous motors 3 through the oil circuit from the first oil port to the third oil port in the first reversing valve 1. After being controlled by the hydraulic synchronous motor 3, the pressure oil enters the rod chambers of the two hydraulic cylinders 5 at the end from the first port of the two hydraulic synchronous motors 3, respectively, and pushes the push rods of the two hydraulic cylinders 5 at the end to retract synchronously; at the same time, the push rods of the two hydraulic cylinders 5 in the middle are also driven to retract. The rod chamber of the hydraulic cylinder 5 is connected to the oil tank 7, and oil is automatically replenished under the action of atmospheric pressure; the hydraulic oil in the rodless chambers of the two hydraulic cylinders 5 at the end returns to the oil tank 7 through the oil circuit from the second oil port to the fourth oil port in the first reversing valve 1; and because the third oil port is also connected to the control oil ports of the middle hydraulic-controlled one-way valves 4, the pressure oil flowing out through the third oil port in the first reversing valve 1 also enters the control oil ports of the middle hydraulic-controlled one-way valves 4, opens the reverse oil circuit of the middle hydraulic-controlled one-way valves 4, and the hydraulic oil in the rodless chambers of the two middle hydraulic cylinders 5 returns to the oil tank 7 through the corresponding hydraulic-controlled one-way valves 4.

[0063] It can be seen that the synchronous hydraulic system of the molding machine of the present invention is equipped with two hydraulic synchronous motors 3 to control the two hydraulic cylinders 5 at the end to always move synchronously. Only when the working pressure reaches the preset value, the four hydraulic cylinders 5 are controlled to be pressurized synchronously to press the workpiece, ensuring that the two ends of the mold block can synchronously contact and press the workpiece, thereby improving the pressing quality of the workpiece. At the same time, the hydraulic cylinders 5 always move synchronously, which can avoid the push rods of the hydraulic cylinders 5 from pulling each other, avoid damage to the sealing ring of the push rod, prevent oil leakage, ensure the reliability of the connection between the push rod of the hydraulic cylinder 5 and the mold block, and improve the service life of each hydraulic cylinder 5 and the mold block.

[0064] In this embodiment, the number of the hydraulic cylinders 5 is four. In practical applications, the number of the hydraulic cylinders 5 is not limited. For example, the number of the hydraulic cylinders 5 can be more than two and can be adaptively adjusted according to the size of the workpiece.

[0065] Furthermore, in this embodiment, a pressure switch 8 and a controller are also included. The pressure switch 8 is used to detect the outlet pressure of the hydraulic oil pump 6. The controller is electrically connected to the pressure switch 8, the first reversing valve 1, and the second reversing valve 2. The controller can detect the outlet pressure of the hydraulic oil pump 6 according to the pressure switch 8 and control the second reversing valve 2 to switch to the third working position; the controller can also control the first reversing valve 1 to switch between the first working position and the second working position according to the pressing process.

[0066] Among them, such as Figure 2As shown, it also includes a first oil path 91, a second oil path 92 and a third oil path 93, the first end of the first oil path 91 communicates with the second oil port, the second end of the first oil path 91 communicates with the first end of the second oil path 92 and the third oil path 93, the second end of the second oil path 92 and the third oil path 93 communicates with the rodless cavity of the two hydraulic cylinders 5 at the end one by one, and the pressure switch 8 is arranged on the first oil path 91.

[0067] Of course, the position of the pressure switch 8 is not limited, for example, the pressure switch 8 can also be arranged on the oil path between the first oil port and the hydraulic oil pump 6.

[0068] The first reversing valve 1 is a three-position four-way reversing valve, and has a first electromagnet and a second electromagnet, when the first electromagnet is powered, the first reversing valve 1 is in the first working position, when the second electromagnet is powered, the first reversing valve 1 is in the second working position, and the controller can control the first electromagnet or the second electromagnet to be powered to control the first reversing valve 1 to switch between the first working position and the second working position according to the pressing process.

[0069] The second reversing valve 2 is a two-position three-way reversing valve, and has a third electromagnet and a control spring, when the third electromagnet is powered, the second reversing valve 2 is in the third working position.

[0070] Further, the first reversing valve 1, the second reversing valve 2, the hydraulic synchronous motor 3, the hydraulic oil pump 6, the two hydraulic cylinders 5 at the end, the two hydraulic cylinders 5 at the middle, the two hydraulic cylinders 5 at the head, the two hydraulic cylinders 5 at the tail, the two hydraulic cylinders 5 at the side, the two hydraulic cylinders 5 at the bottom, the two hydraulic cylinders 5 at the top, the two hydraulic cylinders 5 at the left and the two hydraulic cylinders 5 at the right are connected to form a hydraulic synchronous system. Figure 1 It can be seen that the prior art four-oil-cylinder hydraulic press machine has a single function, and only four oil cylinders can act at the same time. For some short workpieces, only two oil cylinders are needed to install short mold blocks for operation, which cannot meet the requirements. Based on this, in order to expand the application range of the synchronous hydraulic system of the press machine and meet the pressing operation of shorter workpieces, the present application also includes:

[0071] The first stop valve 10 is arranged on the oil path between the second port of the hydraulic synchronous motor 3 and the third oil port,

[0072] The second stop valve 11 is arranged on the first oil path 91,

[0073] The third stop valve 12 is arranged on the oil path between the sixth oil port and the control oil port of the two hydraulic control check valves 4 at the end,

[0074] The fourth oil path 94 and the fourth stop valve 13, the first end of the fourth oil path 94 communicates with the second oil path 92 / third oil path 93, the second end of the fourth oil path 94 communicates with the rodless cavity of the hydraulic cylinder 5 adjacent to the corresponding end hydraulic cylinder 5, and the fourth stop valve 13 is arranged on the fourth oil path 94,

[0075] The fifth oil circuit 95 and the fifth shut-off valve 14 are connected. The fifth oil circuit 95 is connected to the rod chamber 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 connected to one hydraulic synchronous motor 3. The fifth shut-off valve 14 is provided on the fifth oil circuit 95.

[0076] The sixth stop valve 15 is provided in the oil path between the rod chamber of the hydraulic cylinder 5 at the other end and the first port of the corresponding hydraulic synchronous motor 3.

[0077] The seventh stop valve 16 is provided in the oil path between the rodless chamber of the hydraulic cylinder 5 at the other end and the second oil port.

[0078] The eighth stop valve 17 is provided on the oil path between the rod chamber of the hydraulic cylinder 5 adjacent to the corresponding end hydraulic cylinder 5 and the oil tank 7.

[0079] The ninth stop valve 18 is provided in the oil path between the rod chamber of each hydraulic cylinder 5 and the oil tank 7.

[0080] The tenth stop valve 19 is provided on the oil path between the inlet ends of the two hydraulically controlled one-way valves 4 at the end portions.

[0081] Thus, when a long workpiece needs to be pressed and four hydraulic cylinders 5 need to be actuated simultaneously, the fourth stop valve 13 and the fifth stop valve 14 are closed, and the remaining stop valves are opened. Figure 2 On the basis of the principle diagram, if the shut-off valve is closed and the oil circuit branch is disconnected, the branch oil circuit is directly deleted; if the shut-off valve is open and the oil circuit branch is connected, the hydraulic shut-off valve is replaced by a straight line. The simplified hydraulic principle diagram is as follows: Figure 3 As shown, the pressing process and the recovery process are as described above and will not be repeated here.

[0082] When a shorter workpiece needs to be pressed, only two hydraulic cylinders 5 need to be actuated simultaneously. The first stop valve 10, the second stop valve 11, the fourth stop valve 13, and the fifth stop valve 14 are opened, and the remaining stop valves are closed. The simplified hydraulic principle diagram is shown in FIG. Figure 4 As shown, the working process of pressing the workpiece is as follows:

[0083] The hydraulic oil pump 6 is controlled to be in the starting state, the first reversing valve 1 is in the 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, the pressure oil from the hydraulic oil pump 6 enters the rodless cavity of one of the hydraulic cylinders 5 and the rodless cavity of the adjacent hydraulic cylinder 5 through the oil channel of the first oil port to the second oil port in the first reversing valve 1, and pushes the push rods of the two hydraulic cylinders 5 to extend.

[0084] When the pressing is completed, the first reversing valve 1 is controlled to be in the second working position, the first oil port and the third oil port are communicated, the second oil port and the fourth oil port are communicated, the pressure oil from the hydraulic oil pump 6 enters the second port of the two hydraulic synchronous motors 3 through the oil channel of the first oil port to the third oil port in the first reversing valve 1, and after being controlled by the hydraulic synchronous motor 3, enters the rod cavity of one of the hydraulic cylinders 5 and the rod cavity of the adjacent hydraulic cylinder 5 from the first port of the two hydraulic synchronous motors 3 respectively, and pushes the push rods of the two hydraulic cylinders 5 to retract synchronously.

[0085] In this way, by setting the on-off valves to switch the oil channels, the two control functions of four-cylinder synchronous action and two-cylinder synchronous action can be realized, and the pressing machine synchronous hydraulic system of the present application is suitable for pressing long workpieces and short workpieces, and realizes one machine with multiple functions, and expands the application range of the pressing machine synchronous hydraulic system.

[0086] Please continue to refer to Figure 2 The present application also comprises an oil return filter 20 and a cooler 21, which are arranged on the oil channel between the fourth oil port and the oil tank 7.

[0087] The present application also provides a control method of a pressing machine synchronous hydraulic system, when it is required to press long workpieces and four hydraulic cylinders 5 are required to act simultaneously, the method comprises the following steps:

[0088] The fourth stop valve 13 and the fifth stop valve 14 are controlled to be closed, the remaining stop valves are opened, the hydraulic oil pump 6 is started, and the first reversing valve 1 is in the first working position, the pressure oil from the hydraulic oil pump 6 enters the rodless cavities of the two end hydraulic cylinders 5, pushes the push rods of the two end hydraulic cylinders 5 to extend, the push rods of the two middle hydraulic cylinders 5 are driven to extend synchronously, and the hydraulic oil in the rod cavities of the two end hydraulic cylinders 5 enters the first ports of the two hydraulic synchronous motors 3 respectively for synchronous control, and the hydraulic oil is returned to the oil tank 7 after being collected;

[0089] When the outlet pressure of the hydraulic oil pump 6 reaches the preset value, the second reversing valve 2 is controlled to switch to the third working position, the pressure oil of the rodless cavity of the two end hydraulic oil cylinders 5 is introduced into the rodless cavity of the middle two hydraulic oil cylinders 5, and the rodless cavity of each hydraulic oil cylinder 5 is simultaneously pressurized to press the workpiece;

[0090] When the pressing is completed, the first reversing valve 1 is controlled to be in the second working position, the pressure oil from the hydraulic oil pump 6 enters the second port of the two hydraulic synchronous motors 3, is synchronously controlled after passing through the hydraulic synchronous motors 3, and then enters the rod cavity of the two end hydraulic oil cylinders 5, respectively, to drive the push rods of the two end hydraulic oil cylinders 5 to retract synchronously, the push rods of the two middle hydraulic oil cylinders 5 are driven to retract synchronously, and the hydraulic oil in the oil tank 7 is automatically supplemented to the rod cavity of the middle hydraulic oil cylinder 5 under the action of atmospheric pressure; and the hydraulic oil in the rodless cavity of each hydraulic oil cylinder 5 returns to the oil tank 7.

[0091] The control method of the synchronous hydraulic system of the die press, by controlling the two end hydraulic oil cylinders 5 through the two hydraulic synchronous motors 3, the two end hydraulic oil cylinders 5 always move synchronously, only when the working pressure reaches the preset value, the four hydraulic oil cylinders 5 are controlled to pressurize synchronously to press the workpiece, which ensures that the two ends of the die block can synchronously contact and press the workpiece, improves the pressing quality of the workpiece, and simultaneously, the synchronous movement of each hydraulic oil cylinder 5 can avoid the mutual pulling of the push rods of the hydraulic oil cylinders 5, avoid damaging the sealing ring of the push rod, prevent oil leakage, ensure the reliability of the connection between the push rod of the hydraulic oil cylinder 5 and the die block, and improve the service life of each hydraulic oil cylinder 5 and the die block.

[0092] Further, when it is necessary to perform the pressing operation on a shorter workpiece, and it is necessary for the two hydraulic oil cylinders 5 to move simultaneously, the following steps are included:

[0093] 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 remaining stop valves are all closed, the hydraulic oil pump 6 is controlled to be started, and the first reversing valve 1 is in the first working position; the pressure oil from the hydraulic oil pump 6 enters the rodless cavity of one end hydraulic oil cylinder 5 and the rodless cavity of the adjacent hydraulic oil cylinder 5 through the first reversing valve 1, and drives the push rods of the two hydraulic oil cylinders 5 to extend;

[0094] When the pressing is completed, the first reversing valve 1 is controlled to be in the second working position, the pressure oil from the hydraulic oil pump 6 enters the second port of the two hydraulic synchronous motors 3 through the first reversing valve 1, is synchronously controlled, and then enters the rod cavity of one end hydraulic oil cylinder 5 and the rod cavity of the adjacent hydraulic oil cylinder 5, to drive the push rods of the two hydraulic oil cylinders 5 to retract synchronously, and the hydraulic oil in the rodless cavity of the two hydraulic oil cylinders 5 returns to the oil tank 7 through the first reversing valve 1.

[0095] Thus, by setting each stop valve to switch the oil circuit on and off, the present application has two control functions of four-cylinder synchronous action and two-cylinder synchronous action, and is suitable for pressing needs of long workpieces and short workpieces, realizes one machine with multiple functions, and expands the application range of the synchronous hydraulic system of the pressing machine.

[0096] The above describes in detail the pressing machine synchronous hydraulic system and control method provided by the present application, and the principles and implementation modes of the present application are described by applying specific examples. The above example is only used to help understand the method and core idea of the present application. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A synchronous hydraulic system for a molding machine, characterized in that: The invention comprises a first reversing valve (1), a second reversing valve (2), two hydraulic synchronous motors (3), two or more hydraulically controlled one-way valves (4), and two or more hydraulic cylinders (5), wherein the hydraulic cylinders (5) are sequentially distributed along the length direction of the mold pressing block, and the push rods of the hydraulic cylinders (5) are connected to the mold pressing block. The first reversing valve (1) has a first oil port, a second oil port, a third oil port and a fourth oil port, and has at least a first working position and a second working position. When located in the first working position, the first oil port is connected to the second oil port, and the third oil port is connected to the fourth oil port; when located in the second working position, the first oil port is connected to the third oil port, and the second oil port is connected to the fourth oil port; The first oil port is connected to the oil tank (7) through the hydraulic oil pump (6), the second oil port is connected to the rodless chambers of the two hydraulic oil cylinders (5) at the end, the rod chambers of the two hydraulic oil cylinders (5) at the end are connected to the first port of the hydraulic synchronous motor (3) in a one-to-one correspondence, the second port of the hydraulic synchronous motor (3) is connected to the third oil port after being combined, and the fourth oil port is connected to the oil tank (7); The second reversing valve (2) has 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. When in the third working position, the fifth oil port and the sixth oil port are connected, and the fifth oil port is connected to the oil tank (7) through the hydraulic oil pump (6); The number of the hydraulic cylinders (5) is more than three. Except for the two hydraulic cylinders (5) at the end, the rod chamber of each hydraulic cylinder (5) in the middle is connected to the oil tank (7). The outlet end of the hydraulic control one-way valve (4) is connected to the rodless chamber of the hydraulic cylinder (5) in a one-to-one correspondence. The inlet end of the two hydraulic control one-way valves (4) at the end is connected to the rodless chamber of each hydraulic cylinder (5) in the middle. The inlet end of each hydraulic control one-way valve (4) in the middle is connected to the oil tank (7). The sixth oil port is connected to the control oil port of the two hydraulic control one-way valves (4) at the end, and the control oil port of each hydraulic control one-way valve (4) in the middle is connected to the third oil port. It also includes a pressure switch (8) and a controller, wherein the pressure switch (8) is used to detect the outlet pressure of the hydraulic oil pump (6), and the controller is electrically connected to the pressure switch (8), the first reversing valve (1), and the second reversing valve (2); It also includes a first oil circuit (91), a second oil circuit (92) and a third oil circuit (93), wherein the first end of the first oil circuit (91) is connected to the second oil port, the second end of the first oil circuit (91) is connected to the second oil circuit (92) and the first end of the third oil circuit (93), the second ends of the second oil circuit (92) and the third oil circuit (93) are connected to the rodless chambers of the two hydraulic cylinders (5) at the end in a one-to-one correspondence, and the pressure switch (8) is arranged in the first oil circuit (91).

2. The synchronous hydraulic system of the molding machine according to claim 1, characterized in that: The number of the hydraulic cylinders (5) is more than three, and further comprises: A first stop valve (10) is provided on the oil path between the second port and the third oil port of the hydraulic synchronous motor (3). The second stop valve (11) is provided on the first oil circuit (91). The third stop valve (12) is provided in the oil circuit between the sixth oil port and the control oil ports of the two hydraulically controlled one-way valves (4) at the end. A fourth oil circuit (94) and a fourth shut-off valve (13), wherein a first end of the fourth oil circuit (94) is in communication with the second oil circuit (92) / the third oil circuit (93), a second end of the third oil circuit (93) is in communication with a rodless chamber of the hydraulic cylinder (5) adjacent to the corresponding end of the hydraulic cylinder (5), and the fourth shut-off valve (13) is provided on the fourth oil circuit (94). A fifth oil circuit (95) and a fifth shut-off valve (14), wherein the fifth oil circuit (95) is connected to the rod chamber of the hydraulic cylinder (5) adjacent to the corresponding end hydraulic cylinder (5) and one of the hydraulic synchronous motors (3), and the corresponding end hydraulic cylinder (5) and the adjacent hydraulic cylinder (5) are respectively connected to one of the hydraulic synchronous motors (3), and the fifth shut-off valve (14) is provided on the fifth oil circuit (95). The sixth stop valve (15) is provided on the oil path between the rod chamber of the hydraulic cylinder (5) at the other end and the first port of the corresponding hydraulic synchronous motor (3). The seventh stop valve (16) is provided on the oil path between the rodless chamber of the hydraulic cylinder (5) at the other end and the second oil port. An eighth stop valve (17) is provided on the oil path between the rod chamber of the hydraulic cylinder (5) adjacent to the corresponding end portion of the hydraulic cylinder (5) and the oil tank (7). The ninth stop valve (18) is provided on the oil path between the rod chamber of each of the hydraulic cylinders (5) in the middle and the oil tank (7). The tenth stop valve (19) is arranged on the oil path between the inlet ends of the two hydraulically controlled one-way valves (4).

3. The synchronous hydraulic system of the molding machine according to any one of claims 1-2, characterized in that: The first reversing valve (1) is a three-position four-way reversing valve and has a first electromagnet and a second electromagnet. When the first electromagnet is energized, the first reversing valve (1) is in a first working position. When the second electromagnet is energized, the first reversing valve (1) is in a second working position.

4. The synchronous hydraulic system of a molding machine according to any one of claims 1 to 2, characterized in that: The second reversing valve (2) is a two-position three-way reversing valve and has a third electromagnet. When the third electromagnet is energized, the second reversing valve (2) is in a third working position.

5. The synchronous hydraulic system of a molding machine according to any one of claims 1 to 2, characterized in that: It also includes an oil return filter (20) and a cooler (21), wherein the oil return filter (20) and the cooler (21) are arranged on the oil path between the fourth oil port and the oil tank (7).

6. A control method for a synchronous hydraulic system of a molding machine, based on the synchronous hydraulic system of a molding machine according to claim 2, characterized in that: When a long workpiece needs to be pressed and four hydraulic cylinders (5) need to be actuated simultaneously, the following steps are included: The fourth stop valve (13) and the fifth stop valve (14) are controlled to be closed, and the other stop valves are all opened, the hydraulic oil pump (6) is controlled to start, and the first reversing valve (1) is in the first working position, the pressure oil from the hydraulic oil pump (6) enters the rodless chambers of the two hydraulic oil cylinders (5) at the end, pushing the push rods of the two hydraulic oil cylinders (5) at the end to extend, and the push rods of the two hydraulic oil cylinders (5) in the middle are driven to extend synchronously, and the hydraulic oil in the rod chambers of the two hydraulic oil cylinders (5) at the end respectively enters the 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); When the outlet pressure of the hydraulic oil pump (6) reaches a preset value, the second reversing valve (2) is controlled to switch to the third working position, and the pressure oil of the rodless chambers of the two hydraulic oil cylinders (5) at the end is introduced into the rodless chambers of the hydraulic oil cylinders (5) in the middle, and the rodless chambers of the hydraulic oil cylinders (5) are pressurized at the same time to press the workpiece; When the pressing is completed, the first reversing valve (1) is controlled to be in the second working position, and the pressure oil from the hydraulic oil pump (6) enters the second port of the two hydraulic synchronous motors (3), and after being synchronously controlled by the hydraulic synchronous motors (3), respectively enters the rod chambers of the two hydraulic cylinders (5) at the end, pushing the push rods of the two hydraulic cylinders (5) at the end to retract synchronously, and the push rods of the two hydraulic cylinders (5) in the middle are driven to retract synchronously, and the hydraulic oil in the oil tank (7) is automatically replenished to the rod chamber of the hydraulic cylinder (5) in the middle under the action of atmospheric pressure; the hydraulic oil in the rodless chamber of each hydraulic cylinder (5) returns to the oil tank (7).

7. The control method of the synchronous hydraulic system of the molding machine according to claim 6, characterized in that: When a shorter workpiece needs to be pressed and two hydraulic cylinders (5) need to be actuated simultaneously, the following steps are included: 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 open, and the remaining stop valves are closed, and the hydraulic oil pump (6) is controlled to start, and the first reversing valve (1) is in the first working position, and the pressure oil from the hydraulic oil pump (6) enters the rodless cavity of one end of the hydraulic oil cylinder (5) and the rodless cavity of the adjacent hydraulic oil cylinder (5) through the first reversing valve (1), pushing the push rods of the two hydraulic oil cylinders (5) to extend; the hydraulic oil in the rod cavities of the two hydraulic oil cylinders (5) respectively enters the 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 the first reversing valve (1); When the pressing is completed, the first reversing valve (1) is controlled to be in the second working position, and the pressure oil from the hydraulic oil pump (6) enters the second port of the two hydraulic synchronous motors (3) through the first reversing valve (1) for synchronous control, and then enters the rod cavity of one end of the hydraulic oil cylinder (5) and the rod cavity of the adjacent hydraulic oil cylinder (5), pushing the push rods of the two hydraulic oil cylinders (5) to retract synchronously, and the hydraulic oil in the rodless cavity of the two hydraulic oil cylinders (5) returns to the oil tank (7) through the first reversing valve (1).

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