A bidirectional pump-controlled bending machine hydraulic system

Abstract

The utility model provides a kind of hydraulic system of two-way pump control bending machine, it is related to hydraulic control technical field, including the two groups of hydraulic control units of symmetrical arrangement in bending machine left and right two ends and same structure, each group of hydraulic control unit includes servo two-way pump control device, hydraulic control valve group and hydraulic cylinder, the hydraulic cylinder in two groups of hydraulic control units is connected with displacement sensor respectively;Servo two-way pump control device includes oil tank, two-way pump, servo motor, the input shaft of two-way pump between the output shaft of servo motor is equipped with the shaft coupling of connecting it, and displacement sensor and corresponding servo motor communication feedback control connection;Hydraulic control valve group includes oil circuit board, three position four-way electromagnetic reversing valve, two position two-way electromagnetic ball valve, normally open two-way cartridge valve, two position four-way electromagnetic reversing valve.The utility model can provide oil pressure and output flow according to the real-time need of working time, and pressure and flow match, realize constant power output, reach energy-saving effect.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, and in particular to a two-way pump-controlled bending machine hydraulic system. Background Technology

[0002] Currently, the hydraulic system of a bending machine mainly uses proportional flow valves to throttle and control the bending speed and synchronization, and proportional pressure valves to control the output pressure changes. However, in actual use, this control method has significant energy loss, causing the system to overheat, have a high failure rate, and affect the service life of the hydraulic system. Utility Model Content

[0003] The purpose of this invention is to provide a two-way pump-controlled hydraulic system for a bending machine, which can provide oil supply pressure and output flow according to the real-time needs during operation, and the pressure and flow are matched to achieve constant power output and achieve energy-saving effect.

[0004] The above-mentioned technical objective of this utility model is achieved through the following technical solution: A bidirectional pump-controlled bending machine hydraulic system includes two sets of hydraulic control units symmetrically arranged at the left and right ends of the bending machine and having the same structure. Each set of hydraulic control units includes a servo bidirectional pump control device, a hydraulic control valve group and a hydraulic cylinder. The hydraulic cylinders in the two sets of hydraulic control units are respectively connected to displacement sensors. The servo bidirectional pump control device includes an oil tank, a bidirectional pump, and a servo motor. A coupling is provided between the output shaft of the servo motor and the input shaft of the bidirectional pump to connect them. The displacement sensor is connected to the corresponding servo motor for communication feedback control. The bidirectional pump includes a first working oil port AA and a second working oil port AB. The first working oil port AA is connected to the oil tank, and the second working oil port AB is connected to a pressure sensor. The hydraulic control valve group includes an oil circuit board, a three-position four-way solenoid directional valve, a two-position two-way solenoid ball valve, a normally open two-way cartridge valve, and a two-position four-way solenoid directional valve. The oil circuit board is provided with oil ports BA, BB, BC, BD and BE. Oil port BA is connected to the oil tank, oil port BB is connected to the second working oil port AB of the bidirectional pump, oil port BC is connected to the rod chamber of the hydraulic cylinder, and oil ports BD and BE are connected to the rodless chamber of the hydraulic cylinder. The three-position four-way solenoid directional valve includes oil ports CP, CT, CA, CB, and electromagnets YVCA and YVCB. Oil port CP is connected to oil port BB of the oil circuit board, oil port CT is connected to oil port BA of the oil circuit board, oil port CA is connected to oil port BC of the oil circuit board through a two-position two-way solenoid ball valve, and oil port CB is connected to oil port BD of the oil circuit board. The normally open two-way cartridge valve includes ports FA, FB, and FC. Port FA is connected to port BE of the oil circuit board, and port FB is connected to port BA of the oil circuit board. The two-position four-way solenoid directional valve includes oil ports DP, DT, DA, DB and an electromagnet YVDA. Oil port DP is connected to oil port BB of the oil circuit board, oil port DT is connected to oil port BA of the oil circuit board, oil port DA is blocked, and oil port DB is connected to oil port FC of a normally open two-way cartridge valve.

[0005] Furthermore, the two-position two-way solenoid ball valve includes oil ports EA and EB and an electromagnet YVEA. Oil port EA is connected to oil port CA of the three-position four-way solenoid directional valve, oil port EB is connected to oil port BC of the oil circuit board, and an overflow valve is also connected between oil ports EA and EB.

[0006] Furthermore, a check valve is provided between the oil port DP of the two-position four-way solenoid directional valve and the oil port BB of the oil circuit board, and the oil inlet of the check valve is connected to the oil port BB, and the oil outlet is connected to the oil port DP.

[0007] Furthermore, when the servo motor inputs a reverse signal, the solenoid YVEA of the two-position two-way solenoid ball valve and the solenoid YVCB of the three-position four-way solenoid directional valve are energized. Under its own weight, the piston rod of the hydraulic cylinder descends rapidly, increasing the volume of the rodless chamber of the hydraulic cylinder. The oil in the oil tank enters the rodless chamber of the hydraulic cylinder through the oil port BA of the oil circuit board, the oil ports FB and FA of the normally open two-way cartridge valve, and the oil port BE of the oil circuit board. The oil in the rod chamber of the hydraulic cylinder enters the oil tank through the oil port BC of the oil circuit board, the oil ports EB and EA of the two-position two-way solenoid ball valve, the oil ports CA and CP of the three-position four-way solenoid directional valve, the oil port BB of the oil circuit board, the second working oil port AB of the bidirectional pump, and the first working oil port AA of the bidirectional pump. The magnitude of the input signal of the servo motor controls the rotation speed of the bidirectional pump, thereby controlling the downward speed of the piston rod of the hydraulic cylinder to make it descend rapidly and smoothly.

[0008] Furthermore, when the servo motor receives a positive signal, the solenoids YVEA, YVCA, and YVDA of the two-position two-way solenoid ball valve, the three-position four-way solenoid directional valve, and the two-position four-way solenoid directional valve are energized. The oil in the tank then flows through the first working port AA, the second working port AB of the bidirectional pump, port BB of the circuit board, the check valve, port DP of the two-position four-way solenoid directional valve, and port DB into port FC of the normally open two-way cartridge valve, cutting off the oil passage between ports FA and FB of the normally open two-way cartridge valve. Simultaneously, the oil also flows from... The oil port BB of the hydraulic circuit board enters the rodless chamber of the hydraulic cylinder through the oil ports CP and CB of the three-position four-way solenoid directional valve and the oil port BD of the hydraulic circuit board; the oil in the rod chamber of the hydraulic cylinder enters the oil tank through the oil port BC of the hydraulic circuit board, the oil ports EB and EA of the two-position two-way solenoid ball valve, the oil ports CA and CT of the three-position four-way solenoid directional valve and the oil port BA of the hydraulic circuit board. The piston rod of the hydraulic cylinder performs a bending loading action, and during the loading process, the pressure signal change of the pressure sensor controls the change of the servo motor input signal, and the servo motor operates at constant power.

[0009] Furthermore, when the servo motor receives a reverse signal, the solenoid YVEA of the two-position two-way solenoid ball valve, the solenoid YVCA of the three-position four-way solenoid directional valve, and the solenoid YVDA of the two-position four-way solenoid directional valve are energized. The oil in the rodless chamber of the hydraulic cylinder returns to the oil tank through the oil port BD of the oil circuit board, the oil port CB and CP of the three-position four-way solenoid directional valve, the oil port BB of the oil circuit board, the second working oil port AB of the bidirectional pump, and the first working oil port AA, so that the oil in the rodless chamber of the hydraulic cylinder is smoothly unloaded.

[0010] Furthermore, when the servo motor receives a positive signal, the solenoid YVEA of the two-position two-way solenoid ball valve and the solenoid YVCB of the three-position four-way solenoid directional valve are energized. The oil in the tank enters the rod chamber of the hydraulic cylinder through the first working port AA and the second working port AB of the bidirectional pump, the port BB of the circuit board, the ports CP and CA of the three-position four-way solenoid directional valve, the ports EA and EB of the two-position two-way solenoid ball valve, and the port BC of the circuit board. The oil in the rodless chamber of the hydraulic cylinder enters the oil tank through the port BE of the circuit board, the ports FA and FB of the normally open two-way cartridge valve, and the port BA of the circuit board. The piston rod of the hydraulic cylinder is rapidly raised to the initial state.

[0011] Furthermore, when the hydraulic cylinder is working, the displacement sensors corresponding to the hydraulic cylinders in the two sets of hydraulic control units provide real-time feedback to control the corresponding servo motors to adjust the input signals, thereby changing the output flow of the corresponding bidirectional pump in real time and controlling the hydraulic cylinders in the two sets of hydraulic control units to work synchronously.

[0012] In summary, this utility model has the following beneficial effects: 1. This utility model adopts two sets of hydraulic control units, left and right, to simultaneously control the hydraulic cylinders at both ends of the bending machine. The synchronous operation of the hydraulic cylinders at both ends is achieved through the servo control of two servo motors. The bidirectional pump controlled by the servo motor can adjust both the oil supply pressure and the output flow rate. It can also provide oil supply pressure and output flow rate according to the real-time needs during operation, which has an energy-saving effect. 2. When the hydraulic cylinder descends rapidly, this utility model utilizes the weight of the equipment to connect the oil in the oil tank with the rodless chamber of the hydraulic cylinder, replenishing the oil to the rodless chamber. The oil in the rod chamber of the hydraulic cylinder returns to the oil tank through a bidirectional pump. Furthermore, the speed of the rapid descent of the hydraulic cylinder is controlled by adjusting the speed of the bidirectional pump, thereby achieving energy saving. 3. During the bending loading process, this utility model uses a pressure sensor to collect signals and control the speed of the servo motor to match the flow rate and pressure, thereby achieving constant power output and further achieving energy-saving effects. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of a two-way pump-controlled bending machine hydraulic system.

[0014] In the diagram, 001 is the hydraulic control unit; 01 is the servo bidirectional pump control device; 02 is the hydraulic control valve group; 03 is the hydraulic cylinder; 1 is the oil tank; 2 is the bidirectional pump; 3 is the servo motor; 4 is the coupling; 5 is the pressure sensor; 6 is the oil circuit board; 7 is the three-position four-way solenoid directional valve; 8 is the two-position two-way solenoid ball valve; 9 is the relief valve; 10 is the normally open two-way cartridge valve; 11 is the two-position four-way solenoid directional valve; 12 is the check valve; 13 is the displacement sensor; 14 is the rodless chamber; 15 is the rod chamber. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0016] A two-way pump-controlled bending machine hydraulic system, such as Figure 1 As shown, the machine includes two sets of hydraulic control units 001 symmetrically arranged at the left and right ends of the bending machine. The two sets of hydraulic control units 001 have the same structure and working principle. Specifically, each set of hydraulic control units 001 includes a servo bidirectional pump control device 01, a hydraulic control valve group 02, and a hydraulic cylinder 03. The servo bidirectional pump control device switches the oil circuit through the hydraulic control valve group 02 to achieve oil supply and return to the hydraulic cylinder 03, controlling the hydraulic cylinder 03 to perform corresponding actions such as rapid descent, bending loading, unloading, and rapid lifting. Each hydraulic cylinder 03 in both sets of hydraulic control units 001 is connected to a displacement sensor 13.

[0017] like Figure 1 As shown, the servo bidirectional pump control device 01 includes an oil tank 1, a bidirectional pump 2, and a servo motor 3. A coupling 4 connects the output shaft of the servo motor 3 and the input shaft of the bidirectional pump 2. The bidirectional pump 2 includes a first working oil port AA and a second working oil port AB. The first working oil port AA is connected to the oil tank 1, and the second working oil port AB is connected to a pressure sensor 5. A displacement sensor 13 is connected to the corresponding servo motor 3 via communication feedback control. Closed-loop control is achieved through the linkage of the displacement sensor 13 and the servo motor 3. Furthermore, when the servo motor 3 receives a positive signal, the first working oil port AA of the bidirectional pump 2 becomes the input port, and the second working oil port AB becomes the output port; when the servo motor 3 receives a negative signal, the second working oil port AB becomes the input port, and the first working oil port AA becomes the output port. Changing the magnitude of the input signal to the servo motor 3 changes the rotational speed of the bidirectional pump 2, thereby controlling the output flow rate of the bidirectional pump 2.

[0018] like Figure 1 As shown, the hydraulic control valve group 02 includes a manifold 6, a three-position four-way solenoid directional valve 7, a two-position two-way solenoid ball valve 8, a relief valve 9, a normally open two-way cartridge valve 10, a two-position four-way solenoid directional valve 11, and a check valve 12. The manifold 6 has ports BA, BB, BC, BD, and BE. Port BA is connected to the oil tank 1, port BB is connected to the second working port AB of the bidirectional pump 2, port BC is connected to the rod chamber 15 of the hydraulic cylinder 03, and ports BD and BE are connected to the rodless chamber 14 of the hydraulic cylinder 03.

[0019] like Figure 1 As shown, the three-position four-way solenoid directional valve 7 includes ports CP, CT, CA, and CB, as well as electromagnets YVCA and YVCB. When both electromagnets YVCA and YVCB are de-energized, port CP is connected to port CT, while ports CA and CB are blocked. When electromagnet YVCA is energized, port CP is connected to port CB, and ports CA and CT are connected. When electromagnet YVCB is energized, port CP is connected to port CA, and ports CB and CT are connected. Additionally, port CP of the three-position four-way solenoid directional valve 7 is connected to port BB of the manifold 6, port CT is connected to port BA of the manifold 6, and port CB is connected to port BD of the manifold 6.

[0020] like Figure 1As shown, the two-position two-way solenoid ball valve 8 includes ports EA and EB and an electromagnet YVEA. When the electromagnet YVEA is de-energized, the oil can only flow from port EA to port EB, and the reverse oil path is closed. When the electromagnet YVEA is energized, the oil paths between ports EA and EB are bidirectionally connected. The relief valve 9 includes ports EP and ET. Port EP is connected to port EB of the two-position two-way solenoid ball valve 8 and then to port BC of the oil circuit board 6. Port ET is connected to port EA of the two-position two-way solenoid ball valve 8 and then to port CA of the three-position four-way solenoid directional valve 7.

[0021] like Figure 1 As shown, the normally open two-way cartridge valve 10 includes ports FA, FB, and FC. Port FA is connected to port BE of the hydraulic manifold 6, and port FB is connected to port BA of the hydraulic manifold 6. When port FC of the normally open two-way cartridge valve 10 has no hydraulic pressure, port FA and port FB are connected. When port FC has hydraulic pressure, the hydraulic circuit between port FA and port FB is cut off.

[0022] like Figure 1 As shown, the two-position four-way solenoid directional valve 11 includes ports DP, DT, DA, DB, and an electromagnet YVDA. When the electromagnet YVDA is de-energized, ports DP and DA are connected, and ports DB and DT are connected. When the electromagnet YVDA is energized, ports DP and DB are connected, and ports DA and DT are connected. Port DP of the two-position four-way solenoid directional valve 11 is connected to port BB of the oil circuit board 6 via check valve 12. The inlet of check valve 12 is connected to port BB of the oil circuit board 6, and its outlet is connected to port DP of the two-position four-way solenoid directional valve 11. Port DT of the two-position four-way solenoid directional valve 11 is connected to port BA of the oil circuit board 6, port DA is blocked, and port DB is connected to port FC of the normally open two-way cartridge valve 10.

[0023] Initial state: such as Figure 1 As shown, the solenoids YVCA and YVCB of the three-position four-way solenoid directional valve 7, the solenoid YVDA of the two-position four-way solenoid directional valve 11, and the solenoid YVEA of the two-position two-way solenoid ball valve 8 are all de-energized. The oil circuit between the oil port EB and the oil port EA of the two-position two-way solenoid ball valve 8 is closed. The oil circuit between the oil port EP and the empty ET of the relief valve 9 is closed. The oil circuit of the rodless chamber 14 of the hydraulic cylinder 03 is closed. The piston cylinder of the hydraulic cylinder 03 is stopped at the upper end.

[0024] Rapid descent: such as Figure 1As shown, when the servo motor 3 receives a reverse signal, the solenoid YVEA of the two-position two-way solenoid ball valve 8 and the solenoid YVCB of the three-position four-way solenoid directional valve 7 are energized. The piston rod of the hydraulic cylinder 03 moves rapidly downwards under its own weight, increasing the volume of the rodless chamber 14 of the hydraulic cylinder 03. Oil from the oil tank 1 enters the rodless chamber 14 of the hydraulic cylinder 03 through the oil port BA of the oil circuit board 6, the oil ports FB and FA of the normally open two-way cartridge valve 10, and the oil port BE of the oil circuit board 6. Oil from the rod chamber 15 of the hydraulic cylinder 03 enters the oil tank 1 through the oil port BC of the oil circuit board 6, the oil ports EB and EA of the two-position two-way solenoid ball valve 8, the oil ports CA and CP of the three-position four-way solenoid directional valve 7, the oil port BB of the oil circuit board 6, and the second working oil port AB and the first working oil port AA of the bidirectional pump 2. The speed of the bidirectional pump 2 can be changed by controlling the magnitude of the input signal of the servo motor 3, thereby controlling the downward speed of the piston rod of the hydraulic cylinder 03 to ensure that the piston rod of the hydraulic cylinder 03 moves down quickly and smoothly.

[0025] Bending load: such as Figure 1 As shown, when the servo motor 3 receives a positive signal, the solenoid YVEA of the two-position two-way solenoid ball valve 8, the solenoid YVCA of the three-position four-way solenoid directional valve 7, and the solenoid YVDA of the two-position four-way solenoid directional valve 11 are energized. The oil in the oil tank 1 enters the normally open two-way cartridge valve 10 through the first working port AA and the second working port AB of the bidirectional pump 2, the port BB of the oil circuit board 6, the check valve 12, the port DP and the port DB of the two-position four-way solenoid directional valve 11, and cuts off the oil circuit between the port FA and the port FB of the normally open two-way cartridge valve 10. At the same time, the oil also enters the rodless chamber 14 of the hydraulic cylinder 03 from the port BB of the oil circuit board 6 through the port CP, the port CB of the three-position four-way solenoid directional valve 7, and the port BD of the oil circuit board 6. The oil in the rod chamber 15 of the hydraulic cylinder 03 enters the oil tank 1 through the oil port BC of the oil circuit board 6, the oil ports EB and EA of the two-position two-way solenoid ball valve 8, the oil ports CA and CT of the three-position four-way solenoid directional valve 7, and the oil port BA of the oil circuit board 6. The piston rod of the hydraulic cylinder 03 performs the bending loading action, and during the loading process, the pressure signal change of the pressure sensor 5 controls the change of the input signal of the servo motor 3, so as to realize the constant power operation of the servo motor 3 during the bending process.

[0026] Uninstall: such as Figure 1 As shown, when the servo motor 3 inputs a reverse signal, the solenoid YVEA of the two-position two-way solenoid ball valve 8, the solenoid YVCA of the three-position four-way solenoid directional valve 7, and the solenoid YVDA of the two-position four-way solenoid directional valve 11 are energized. The oil in the rodless chamber 14 of the hydraulic cylinder 03 returns to the oil tank 1 through the oil port BD of the oil circuit board 6, the oil port CB and CP of the three-position four-way solenoid directional valve 7, the oil port BB of the oil circuit board 6, the second working oil port AB of the bidirectional pump 2, and the first working oil port AA. The oil in the rodless chamber 14 of the hydraulic cylinder 03 is smoothly unloaded.

[0027] Rapid improvement: such as Figure 1 As shown, when the servo motor 3 receives a positive signal, the solenoid YVEA of the two-position two-way solenoid ball valve 8 and the solenoid YVCB of the three-position four-way solenoid directional valve 7 are energized. The oil in the oil tank 1 enters the rod chamber 15 of the hydraulic cylinder 03 through the first working port AA and the second working port AB of the bidirectional pump 2, the port BB of the oil circuit board 6, the ports CP and CA of the three-position four-way solenoid directional valve 7, the ports EA and EB of the two-position two-way solenoid ball valve 8, and the port BC of the oil circuit board 6. The oil in the rodless chamber 14 of the hydraulic cylinder 03 enters the oil tank 1 through the port BE of the oil circuit board 6, the ports FA and FB of the normally open two-way cartridge valve 10, and the port BA of the oil circuit board 6. The piston rod of the hydraulic cylinder 03 is rapidly raised to the initial state.

[0028] Synchronization control: such as Figure 1 As shown, when the hydraulic cylinder 03 is working, it collects the signal from the displacement sensor 13 corresponding to the hydraulic cylinder 03 in the two sets of hydraulic control units 001, and controls the corresponding servo motor 3 to adjust the input signal in real time, thereby adjusting the speed of the corresponding servo motor 3 and changing the output flow of the corresponding bidirectional pump 2 in real time, so as to realize the synchronous operation of the hydraulic cylinder 03 in the two sets of hydraulic control units 001.

[0029] like Figure 1 As shown, this utility model employs two sets of hydraulic control units 001, one on the left and one on the right, to simultaneously control the hydraulic cylinders 03 at both ends of the bending machine. Synchronous operation of the hydraulic cylinders 03 at both ends is achieved through the servo control of two servo motors 3. The servo motors 3 control the bidirectional pump 2, enabling regulation of both the oil supply pressure and the output flow rate. It can also provide oil supply pressure and output flow rate according to real-time needs during operation, resulting in energy savings. Specifically, during the rapid downward movement of the hydraulic cylinder 03, the oil in the oil tank 1 connects to the rodless chamber 14 of the hydraulic cylinder 03 using the equipment's own weight, replenishing the rodless chamber 14. The oil in the rod chamber 15 of the hydraulic cylinder 03 returns to the oil tank 1 via the bidirectional pump 2. The rapid downward movement speed of the hydraulic cylinder 03 is controlled by adjusting the speed of the bidirectional pump 2, achieving energy savings. Furthermore, during the bending loading process, the speed of the servo motor 3 is controlled by the signal collected by the pressure sensor 5 to match the flow rate and pressure, achieving constant power output and further enhancing energy efficiency.

[0030] The foregoing description illustrates and describes preferred embodiments of the present invention. As previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or related technical or knowledge. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A bidirectional pump-controlled bending machine hydraulic system, characterized in that: It includes two sets of hydraulic control units (001) symmetrically arranged at the left and right ends of the bending machine and having the same structure. Each set of hydraulic control units (001) includes a servo bidirectional pump control device (01), a hydraulic control valve group (02) and a hydraulic cylinder (03). The hydraulic cylinders (03) in the two sets of hydraulic control units (001) are respectively connected to displacement sensors (13). The servo bidirectional pump control device (01) includes an oil tank (1), a bidirectional pump (2), and a servo motor (3). A coupling (4) is provided between the output shaft of the servo motor (3) and the input shaft of the bidirectional pump (2) to connect them. The displacement sensor (13) is connected to the corresponding servo motor (3) for communication feedback control. The bidirectional pump (2) includes a first working oil port AA and a second working oil port AB. The first working oil port AA is connected to the oil tank (1), and the second working oil port AB is connected to a pressure sensor (5). The hydraulic control valve group (02) includes an oil circuit board (6), a three-position four-way solenoid directional valve (7), a two-position two-way solenoid ball valve (8), a normally open two-way cartridge valve (10), and a two-position four-way solenoid directional valve (11). The oil circuit board (6) is provided with oil ports BA, BB, BC, BD and BE. Oil port BA is connected to the oil tank (1), oil port BB is connected to the second working oil port AB of the bidirectional pump (2), oil port BC is connected to the rod chamber (15) of the hydraulic cylinder (03), and oil ports BD and BE are connected to the rodless chamber (14) of the hydraulic cylinder (03). The three-position four-way solenoid directional valve (7) includes oil ports CP, CT, CA, CB and electromagnets YVCA and YVCB. Oil port CP is connected to oil port BB of the oil circuit board (6), oil port CT is connected to oil port BA of the oil circuit board (6), oil port CA is connected to oil port BC of the oil circuit board (6) through a two-position two-way solenoid ball valve (8), and oil port CB is connected to oil port BD of the oil circuit board (6). The normally open two-way cartridge valve (10) includes ports FA, FB, and FC. Port FA is connected to port BE of the oil circuit board (6), and port FB is connected to port BA of the oil circuit board (6). The two-position four-way solenoid directional valve (11) includes oil ports DP, DT, DA, DB and electromagnet YVDA. Oil port DP is connected to oil port BB of the oil circuit board (6), oil port DT is connected to oil port BA of the oil circuit board (6), oil port DA is blocked, and oil port DB is connected to oil port FC of the normally open two-way cartridge valve (10).

2. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 1, characterized in that: The two-position two-way solenoid ball valve (8) includes oil ports EA and EB and an electromagnet YVEA. The oil port EA is connected to the oil port CA of the three-position four-way solenoid directional valve (7), the oil port EB is connected to the oil port BC of the oil circuit board (6), and an overflow valve (9) is also connected between the oil ports EA and EB.

3. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 2, characterized in that: A check valve (12) is provided between the oil port DP of the two-position four-way solenoid directional valve (11) and the oil port BB of the oil circuit board (6). The oil inlet of the check valve (12) is connected to the oil port BB, and the oil outlet is connected to the oil port DP.

4. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 3, characterized in that: The servo motor (3) inputs a reverse signal, energizing the electromagnet YVEA of the two-position two-way solenoid ball valve (8) and the electromagnet YVCB of the three-position four-way solenoid directional valve (7). The piston rod of the hydraulic cylinder (03) moves rapidly downward under its own weight, increasing the volume of the rodless chamber (14) of the hydraulic cylinder (03). The oil in the oil tank (1) enters the rodless chamber (14) of the hydraulic cylinder (03) through the oil port BA of the oil circuit board (6), the oil port FB and FA of the normally open two-way cartridge valve (10), and the oil port BE of the oil circuit board (6). 4); The oil in the rod chamber (15) of the hydraulic cylinder (03) enters the oil tank (1) through the oil port BC of the oil circuit board (6), the oil port EB and oil port EA of the two-position two-way solenoid ball valve (8), the oil port CA and oil port CP of the three-position four-way solenoid directional valve (7), the oil port BB of the oil circuit board (6), the second working oil port AB and the first working oil port AA of the bidirectional pump (2); The input signal of the servo motor (3) controls the rotation speed of the bidirectional pump (2) and controls the downward speed of the piston rod of the hydraulic cylinder (03) so that it descends quickly and smoothly.

5. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 3, characterized in that: When the servo motor (3) receives a positive signal, the electromagnet YVEA of the two-position two-way solenoid ball valve (8), the electromagnet YVCA of the three-position four-way solenoid directional valve (7), and the electromagnet YVDA of the two-position four-way solenoid directional valve (11) are energized. The oil in the oil tank (1) enters the normally open two-way cartridge valve (10) through the first working port AA, the second working port AB of the bidirectional pump (2), the port BB of the oil circuit board (6), the check valve (12), the port DP and port DB of the two-position four-way solenoid directional valve (11), and cuts off the oil circuit between the port FA and port FB of the normally open two-way cartridge valve (10). At the same time, the oil also flows from the port B of the oil circuit board (6). B enters the rodless chamber (14) of the hydraulic cylinder (03) through the oil ports CP and CB of the three-position four-way solenoid directional valve (7) and the oil port BD of the oil circuit board (6); the oil in the rod chamber (15) of the hydraulic cylinder (03) enters the oil tank (1) through the oil ports BC of the oil circuit board (6), the oil ports EB and EA of the two-position two-way solenoid ball valve (8), the oil ports CA and CT of the three-position four-way solenoid directional valve (7), and the oil port BA of the oil circuit board (6). The piston rod of the hydraulic cylinder (03) performs a bending loading action, and during the loading process, the pressure signal change of the pressure sensor (5) controls the change of the input signal of the servo motor (3), and the servo motor (3) operates at constant power.

6. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 3, characterized in that: When the servo motor (3) inputs a reverse signal, the electromagnet YVEA of the two-position two-way solenoid ball valve (8), the electromagnet YVCA of the three-position four-way solenoid directional valve (7), and the electromagnet YVDA of the two-position four-way solenoid directional valve (11) are energized. The oil in the rodless chamber (14) of the hydraulic cylinder (03) returns to the oil tank (1) through the oil port BD of the oil circuit board (6), the oil port CB and CP of the three-position four-way solenoid directional valve (7), the oil port BB of the oil circuit board (6), the second working oil port AB and the first working oil port AA of the bidirectional pump (2). The oil in the rodless chamber (14) of the hydraulic cylinder (03) is smoothly unloaded.

7. The hydraulic system for a bidirectional pump-controlled bending machine according to claim 3, characterized in that: When the servo motor (3) inputs a positive signal, the electromagnet YVEA of the two-position two-way solenoid ball valve (8) and the electromagnet YVCB of the three-position four-way solenoid directional valve (7) are energized. The oil in the oil tank (1) enters the rod chamber (15) of the hydraulic cylinder (03) through the first working port AA, the second working port AB of the bidirectional pump (2), the port BB of the oil circuit board (6), the port CP, the port CA of the three-position four-way solenoid directional valve (7), the port EA, the port EB of the two-position two-way solenoid ball valve (8), and the port BC of the oil circuit board (6). The oil in the rodless chamber (14) of the hydraulic cylinder (03) enters the oil tank (1) through the port BE of the oil circuit board (6), the port FA, the port FB of the normally open two-way cartridge valve (10), and the port BA of the oil circuit board (6). The piston rod of the hydraulic cylinder (03) is rapidly raised to the initial state.

8. A bidirectional pump-controlled bending machine hydraulic system according to any one of claims 4 to 7, characterized in that: When the hydraulic cylinder (03) is working, the displacement sensor (13) corresponding to the hydraulic cylinder (03) in the two sets of hydraulic control units (001) provides real-time feedback control to the corresponding servo motor (3) to adjust the input signal, thereby changing the output flow of the corresponding bidirectional pump (2) in real time and controlling the hydraulic cylinder (03) in the two sets of hydraulic control units (001) to work synchronously.

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