Double-speed working mode of electro-hydraulic numerical control synchronous bending machine and hydraulic system of electro-hydraulic numerical control synchronous bending machine

Abstract

The invention discloses a double-speed working mode of an electro-hydraulic numerical control synchronous bending machine and a hydraulic system of the electro-hydraulic numerical control synchronous bending machine, which belong to the technical field of hydraulic systems, comprise a servo motor, a servo pump and an oil tank, and are characterized in that the output end of the servo motor is fixedly connected with a rotating part of the servo pump, and an oil suction port of the servo pump is communicated with an oil outlet of the oil tank; an oil discharge port of the servo pump is connected with two groups of hydraulic speed regulating systems; the two groups of hydraulic speed regulating systems are connected with an oil return port of the oil tank; the hydraulic speed regulating system comprises a main pressure overflow valve, a proportional reversing valve, a safety valve, a back pressure valve, a quick descending valve, a first two-position four-way reversing valve, a second two-position four-way reversing valve, a prefill valve, a speed increasing oil cylinder, a first throttling hole and a second throttling hole. Adjustment of two working modes of the hydraulic system is achieved so as to adapt to different working condition requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic systems, and in particular to a dual-speed working mode of an electro-hydraulic numerically controlled synchronous bending machine and a hydraulic system thereof. Background Art

[0002] As one of the indispensable equipment in the sheet metal manufacturing industry, the quality of the electro-hydraulic CNC bending machine depends on the control accuracy of the machine tool, and the production efficiency depends on the speed of the machine tool.

[0003] Nowadays, each cycle of CNC bending machines can be divided into six processes: fast down, working feed, pressure maintenance, pressure relief, return, and stop. In each working process, the pressure and speed provided to the hydraulic system are also different. In the process of fast down, the slide of the traditional CNC bending machine can only rely on the slide's own weight to fall, and the speed is slow, which makes the single cycle time longer. In the process of working feed, the working feed speed cannot be changed due to changes in working conditions, so the work efficiency is low.

[0004] Therefore, the traditional electro-hydraulic CNC synchronous bending machine has low efficiency in the entire cycle mode compared to the double-speed working mode hydraulic system of the electro-hydraulic CNC synchronous bending machine.

[0005] Based on this, the present invention designs a dual-speed working mode of an electro-hydraulic numerically controlled synchronous bending machine and its hydraulic system to solve the above problems. Summary of the invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a dual-speed working mode of an electro-hydraulic numerically controlled synchronous bending machine and a hydraulic system thereof.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] A hydraulic system of an electro-hydraulic numerically controlled synchronous bending machine comprises a servo motor, a servo pump and an oil tank, wherein the output end of the servo motor is fixedly connected to the rotating part of the servo pump, the oil suction port of the servo pump is communicated with the oil outlet of the oil tank, the oil discharge port of the servo pump is connected to two sets of hydraulic speed regulating systems, and the two sets of hydraulic speed regulating systems are both connected to the oil return port of the oil tank;

[0009] The hydraulic speed control system includes a main pressure relief valve, a proportional reversing valve, a safety valve, a back pressure valve, a quick-down valve, a two-position four-way reversing valve 1, a two-position four-way reversing valve 2, a filling valve, a booster oil cylinder, a throttle hole 1 and a throttle hole 2;

[0010] The oil discharge port of the servo pump is connected to the proportional reversing valve and the main pressure relief valve;

[0011] The proportional reversing valve is connected to the oil tank, the quick-down valve, the main pressure relief valve, the second two-position four-way reversing valve, the first two-position four-way reversing valve, and the booster cylinder, and the main pressure relief valve is connected to the second two-position four-way reversing valve and the oil tank;

[0012] The lower chamber oil port of the booster cylinder is connected to the throttle hole 2, the throttle hole 1, the oil tank, the safety valve, and the filling valve. The upper chamber oil port of the booster cylinder is connected to the two-position four-way reversing valve 1, the filling valve, the oil tank, and the proportional reversing valve. The filling valve is connected to the main pressure relief valve, the oil tank, the two-position four-way reversing valve 2, and the two-position four-way reversing valve 1.

[0013] The throttle hole 2 is connected with the safety valve, the quick-down valve, the back pressure valve and the throttle hole 1.

[0014] Furthermore, the quick-release valve is provided with an electromagnet YV1 for controlling the closing thereof.

[0015] Furthermore, the proportional reversing valve is provided with four ports A, B, P, and T, and the proportional reversing valve is also provided with an electromagnet YV3 and an electromagnet YV4 for controlling the connection between its A port and P port and T port, and between its B port and A port and T port.

[0016] Furthermore, the two-position four-way reversing valve 1 and the two-position four-way reversing valve 2 have the same structure and are both provided with four ports A, B, P, and T. The two-position four-way reversing valve 1 is provided with an electromagnet YV2 for controlling the connection between its A port and P port, T port, and between its B port and A port, T port; the two-position four-way reversing valve 2 is provided with an electromagnet YV5 for controlling the connection between its A port and P port, T port, and between its B port and A port, T port.

[0017] Furthermore, the A port of the proportional reversing valve is connected to the back pressure valve and the quick-down valve through a pipeline, the B port of the proportional reversing valve is connected to the upper chamber oil port of the boosting cylinder, the P port of the two-position four-way reversing valve one, and the B port of the two-position four-way reversing valve one, the P port of the proportional reversing valve is connected to the oil discharge port of the servo pump, the T port of the proportional reversing valve is connected to the safety valve, the main pressure relief valve, the T port of the two-position four-way reversing valve two, and the filling valve through a pipeline, the B port of the two-position four-way reversing valve one is connected to the upper chamber oil port of the boosting cylinder, the B port of the two-position four-way reversing valve two is connected to the filling valve, and the T port of the two-position four-way reversing valve two is connected to the filling valve and the oil tank.

[0018] The present invention also provides a dual-speed working mode of an electro-hydraulic numerically controlled synchronous bending machine:

[0019] There are standard mode and fast mode.

[0020] There are standard mode and fast mode.

[0021] The standard mode uses the following control steps:

[0022] Step 1, fast down: electromagnets YV1 and YV4 are energized, the servo motor drives the servo pump to rotate, the servo pump oil suction port is connected to the oil tank, and the main pressure oil flows to the P-B port of the proportional reversing valve without exceeding the pressure setting of the main pressure relief valve, and flows from the B port to the upper chamber of the speed-increasing oil cylinder; the oil port of the lower chamber of the speed-increasing oil cylinder flows back to the oil tank through the quick down valve-proportional reversing valve A port-T port, the filling valve is normally open, and the speed-increasing oil cylinder quickly absorbs oil from the oil tank under the action of the deadweight of the slide plate and flows through the filling valve;

[0023] Step 2, working advance: electromagnets YV2, YV4, and YV5 are energized, and the pressure oil is divided into three branches: the first branch flows to the P-B port of the proportional reversing valve, and flows from the B port to the upper chamber of the speed-increasing oil cylinder, playing the role of working advance of the upper chamber; the second branch flows to the two-position four-way reversing valve 1, through P-B-the upper chamber of the speed-increasing oil cylinder, playing the role of working advance of the upper chamber of the speed-increasing oil cylinder; the third branch flows to the two-position four-way reversing valve 2, P-B-the filling valve, and closes the filling valve; the lower chamber of the speed-increasing oil cylinder flows back to the oil tank through the back pressure valve-the A port-the T port of the proportional reversing valve, and finally flows to the oil tank;

[0024] Step 3, pressure maintenance: same as step 2;

[0025] Step 4, pressure relief: electromagnets YV2, YV3, and YV5 are energized, and the pressure oil in the upper chamber of the speed-increasing oil cylinder flows in the reverse direction through the A port to the T port of the two-position four-way reversing valve 1 - proportional reversing valve to flow back to the oil tank. At the same time, the pressure oil in the upper chamber of the speed-increasing oil cylinder flows in the reverse direction through the A port to the T port of the proportional reversing valve to flow back to the oil tank. The filling valve controls the pressure oil flow to flow in the reverse direction through the two-position four-way reversing valve 2, and flows from B to T to the oil tank. The filling valve is opened to connect the upper chamber of the speed-increasing oil cylinder with the oil tank, and the pressure oil flows back to the oil tank. At this time, the upper chamber of the speed-increasing oil cylinder completes the pressure relief condition;

[0026] Step 5, return stroke: the electromagnet YV3 is energized, and the pressure oil only flows through the P-A-fast lower valve-lower chamber of the proportional reversing valve, the upper chamber of the speed-increasing cylinder-filling valve-oil tank. At this time, the lower chamber of the speed-increasing cylinder drives the piston to return stroke under the action of the pressure oil;

[0027] Step 6: Stop: All electromagnets are de-energized, the servo motor stops, and the machine tool is in a stationary state.

[0028] The fast mode uses the following control steps:

[0029] Step 1, fast down: electromagnet YV4 is energized, the servo motor drives the servo pump to rotate, the servo pump oil suction port is connected to the oil tank, and the main pressure oil flows to the P-B port of the proportional reversing valve without exceeding the pressure setting of the main pressure relief valve, and flows from the B port to the upper chamber of the speed-increasing oil cylinder to speed up the fast down speed of the speed-increasing oil cylinder; the back pressure valve at the lower chamber of the speed-increasing oil cylinder - the A port - the T port of the proportional reversing valve flows back to the oil tank;

[0030] Step 2, working advance: the electromagnet YV4 is energized, the pressure oil flows to the P-B port of the proportional reversing valve, flows from the B port to the upper chamber of the speed-increasing oil cylinder, and the lower chamber of the speed-increasing oil cylinder flows back to the oil tank through the back pressure valve-the A port-the T port of the proportional reversing valve, and finally flows to the oil tank;

[0031] Step 3, pressure maintenance: same as step 2;

[0032] Step 4, pressure relief: the electromagnet YV3 is energized, and the pressure oil in the upper chamber of the speed increasing cylinder simultaneously flows in the opposite direction through the A port to the T port of the proportional reversing valve and flows back to the oil tank, and the pressure oil flows back to the oil tank;

[0033] Step 5, return stroke: the electromagnet YV3 is energized, and the pressure oil only flows through the P-A-fast lower valve-lower chamber of the proportional reversing valve, the upper chamber of the speed-increasing cylinder-filling valve-oil tank. At this time, the lower chamber of the speed-increasing cylinder drives the piston to return stroke under the action of the pressure oil;

[0034] Step 6: Stop: All electromagnets are de-energized and the servo motor stops.

[0035] Compared with the prior art, the present invention has the following beneficial effects: 1. When the present invention is used, the dual-speed working mode of the electro-hydraulic CNC synchronous bending machine and its hydraulic system enable the CNC bending machine slide to achieve accelerated movement during the fast-down process, greatly improving the working speed within a small load range, shortening the single cycle time, and improving work efficiency. The bending force requirement is guaranteed under the standard mode working condition, and the bending speed requirement is met under the fast mode working condition.

[0036] 2. When the present invention is used, the oil flow is controlled by the throttle hole 1 and the throttle hole 2, thereby preventing the system from being impacted by excessive flow.

[0037] 3. When the present invention is used, a relatively large pressure is required to control the machine tool, which is set to the maximum pressure that the lower chamber of the speed-increasing oil cylinder 11 can withstand through the safety valve. By setting the back pressure valve, the slide of the machine tool can be kept stationary in any non-pressurized working condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 It is a schematic diagram of a hydraulic system of an electro-hydraulic numerically controlled synchronous bending machine of the present invention;

[0040] Figure 2 A schematic diagram of a proportional reversing valve of the present invention;

[0041] Figure 3 It is a schematic diagram of the quick-release valve of the present invention;

[0042] Figure 4 It is a schematic diagram of a two-position four-way reversing valve 1 and a two-position four-way reversing valve 2 of the present invention;

[0043] Figure 5 A table schematic diagram of a standard mode of the present invention;

[0044] Figure 6 It is a table schematic diagram of the fast mode of the present invention.

[0045] The numbers in the figure represent:

[0046] 1. Servo motor; 2. Servo pump; 3. Main pressure relief valve; 4. Proportional reversing valve; 5. Safety valve; 6. Back pressure valve; 7. Quick lowering valve; 8. Two-position four-way reversing valve 1; 9. Two-position four-way reversing valve 2; 10. Filling valve; 11. Speed ​​increasing cylinder 11; 12. Throttle hole 1; 13. Throttle hole 2; 14. Oil tank 14. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] The terms “left”, “right”, “front”, “back”, “up” and “down” mentioned in the following description are oriented in the viewing direction of the front view.

[0049] Embodiment 1: In some embodiments, please refer to the drawings of the specification Figure 1-Figure 6 , a dual-speed working mode of an electro-hydraulic CNC synchronous bending machine and its hydraulic system, comprising a servo motor 1, a servo pump 2 and an oil tank 14, wherein the output end of the servo motor 1 is fixedly connected to the rotating part of the servo pump 2, the oil suction port of the servo pump 2 is connected to the oil outlet of the oil tank 14, and the oil discharge port of the servo pump 2 is connected to two sets of hydraulic speed control systems, and both sets of hydraulic speed control systems are connected to the oil return port of the oil tank 14;

[0050] The hydraulic speed control system includes a main pressure relief valve 3, a proportional reversing valve 4, a safety valve 5, a back pressure valve 6, a quick lowering valve 7, a two-position four-way reversing valve 1 8, a two-position four-way reversing valve 2 9, a filling valve 10, a booster cylinder 11, a throttle hole 1 12 and a throttle hole 2 13;

[0051] The oil discharge port of the servo pump 2 is connected to the proportional reversing valve 4 and the main pressure relief valve 3;

[0052] The proportional reversing valve 4 is connected to the oil tank 14, the quick lowering valve 7, the main pressure relief valve 3, the two-position four-way reversing valve 2 9, the two-position four-way reversing valve 1 8, and the booster cylinder 11, and the main pressure relief valve 3 is connected to the two-position four-way reversing valve 2 9 and the oil tank 14;

[0053] The lower chamber oil port of the boost cylinder 11 is connected to the throttle hole 2 13, the throttle hole 1 12, the safety valve 5, the back pressure valve 6, and the quick lower valve 7. The upper chamber oil port of the boost cylinder 11 is connected to the two-position four-way reversing valve 1 8, the filling valve 10, the oil tank 14, and the proportional reversing valve 4. The filling valve 10 is connected to the main pressure relief valve 3, the oil tank 14, the two-position four-way reversing valve 2 9, and the two-position four-way reversing valve 1 8;

[0054] The throttle hole 2 13 is connected with the safety valve 5 , the quick-down valve 7 , the back pressure valve 6 , and the throttle hole 12 .

[0055] When the present invention is used, the dual-speed working mode of the electro-hydraulic CNC synchronous bending machine and its hydraulic system enable the CNC bending machine slide to achieve accelerated movement during the fast-down process, greatly improving the working speed within a small load range, shortening the single cycle time, and improving work efficiency. The bending force requirement is guaranteed under the standard mode working condition, and the bending speed requirement is met under the fast mode working condition.

[0056] A slide plate is fixedly mounted on the output end of the speed increasing cylinder 11 .

[0057] Embodiment 2: In some embodiments, Figure 1-Figure 6 As shown, as a preferred embodiment of the present invention, the quick-down valve 7 is provided with an electromagnet YV1 for controlling the closing thereof;

[0058] The proportional reversing valve 4 is provided with four ports A, B, P, and T. The proportional reversing valve 4 is also provided with an electromagnet YV3 and an electromagnet YV4 for controlling the communication between its A port and the P port and the T port, and between its B port and the A port and the T port;

[0059] The two-position four-way reversing valve 1 8 and the two-position four-way reversing valve 2 9 have the same structure, and are both provided with four ports A, B, P, and T. The two-position four-way reversing valve 1 8 is provided with an electromagnet YV2 for controlling the connection between its A port and the P port and the T port, and the B port and the A port and the T port. The two-position four-way reversing valve 2 9 is provided with an electromagnet YV5 for controlling the connection between its A port and the P port and the T port, and the B port and the A port and the T port.

[0060] The A port of the proportional reversing valve is connected to the back pressure valve and the quick lower valve through pipelines, the B port of the proportional reversing valve is connected to the upper chamber oil port of the boosting cylinder and the P port of the two-position four-way reversing valve 1, the P port of the proportional reversing valve is connected to the oil discharge port of the servo pump and the main pressure relief valve, the T port of the proportional reversing valve is connected to the safety valve, the main pressure relief valve, the T port of the two-position four-way reversing valve 2, and the filling valve through pipelines, the B port of the two-position four-way reversing valve 1 is connected to the upper chamber oil port of the boosting cylinder, the B port of the two-position four-way reversing valve 2 is connected to the filling valve, and the T port of the two-position four-way reversing valve 2 is connected to the filling valve and the oil tank. When the present invention is used, the oil circuit flow is controlled through the throttle hole 1 and the throttle hole 2, thereby preventing the system from being impacted by excessive flow.

[0061] When the present invention is used, a relatively large pressure is required to control the machine tool, which is set to the maximum pressure that the lower chamber of the speed increasing oil cylinder 11 can withstand through the safety valve 5, and the back pressure valve 6 is used to make the slide of the machine tool stationary in any non-pressurized working condition.

[0062] Embodiment 3: In some embodiments, Figure 1-Figure 6 As shown, as a preferred embodiment of the present invention, the following steps are also included: having a standard mode and a fast mode;

[0063] The standard mode uses the following control steps:

[0064] Step 1, fast down: electromagnets YV1 and YV4 are energized, servo motor 1 drives servo pump 2 to rotate, servo pump 2 oil suction port is connected to oil tank 14, main pressure oil flows to P-B port of proportional reversing valve 4 without exceeding the pressure setting of main pressure relief valve 3, and flows from B port to the upper chamber of speed-increasing oil cylinder 11; the oil port of the lower chamber of speed-increasing oil cylinder 11 flows back to oil tank 14 through quick down valve 7-A port-T port of proportional reversing valve 4, filling valve 10 is normally open, and speed-increasing oil cylinder 11 quickly absorbs oil from oil tank 14 under the action of the deadweight of slide plate and flows through filling valve 10;

[0065] Step 2, working advance: electromagnets YV2, YV4, and YV5 are energized, and the pressure oil is divided into three branches: the first branch flows to the P-B port of the proportional reversing valve 4, and flows from the B port to the upper chamber of the speed-increasing cylinder 11, playing the role of working advance of the upper chamber; the second branch flows to the two-position four-way reversing valve 1 8, through P-B-the upper chamber of the speed-increasing cylinder 11, playing the role of working advance of the upper chamber of the speed-increasing cylinder 11; the third branch flows to the two-position four-way reversing valve 2 9, P-B-the filling valve 10, and the filling valve 10 is closed; the lower chamber of the speed-increasing cylinder 11 flows back to the oil tank 14 through the back pressure valve 6-the A port-T port of the proportional reversing valve 4, and finally flows to the oil tank 14; the machine tool moves downward quickly;

[0066] Step 3, maintaining pressure: the same as step 2; only the speed and torque of the servo motor 1 need to be adjusted to achieve pressure maintenance.

[0067] Step 4, pressure relief: electromagnets YV2, YV3, and YV5 are energized, and the pressure oil in the upper chamber of the speed-increasing oil cylinder 11 flows in the reverse direction through the two-position four-way reversing valve 18-the A port-the T port of the proportional reversing valve 4 and flows back to the oil tank 14. At the same time, the pressure oil in the upper chamber of the speed-increasing oil cylinder 11 flows in the reverse direction through the A port-the T port of the proportional reversing valve 4 and flows back to the oil tank 14. The filling valve 10 controls the pressure oil flow to flow in the reverse direction through the two-position four-way reversing valve 29 and flows from B-T to the oil tank 14. The filling valve 10 is opened to connect the upper chamber of the speed-increasing oil cylinder 11 with the oil tank 14, and the pressure oil flows back to the oil tank 14. At this time, the upper chamber of the speed-increasing oil cylinder 11 completes the pressure relief working condition;

[0068] Step 5, return stroke: the electromagnet YV3 is energized, and the pressure oil only flows through the P-A of the proportional reversing valve 4-the quick lower valve 7-the lower chamber of the speed-increasing oil cylinder 11, the upper chamber of the speed-increasing oil cylinder 11-the filling valve 10-the oil tank 14. At this time, the lower chamber of the speed-increasing oil cylinder 11 increases the speed of the servo motor 1 under the action of the pressure oil, which can increase the return speed of the machine tool;

[0069] Step 6: Stop: All electromagnets are de-energized, servo motor 1 stops rotating, and the machine tool is in a stationary state.

[0070] The fast mode uses the following control steps:

[0071] Step 1, fast down: electromagnet YV4 is energized, servo motor 1 drives servo pump 2 to rotate, servo pump 2 oil suction port is connected to oil tank 14, main pressure oil flows to P-B port of proportional reversing valve 4 without exceeding the pressure setting of main pressure relief valve 3, and flows from port B to the upper chamber of speed-up cylinder 11, accelerating the speed of speed-up cylinder 11 down; oil port back pressure valve 6 of lower chamber of speed-up cylinder 11-port A-port T of proportional reversing valve 4 flows back to oil tank 14, thus achieving the effect of fast down of machine tool. At this time, the speed of fast down is determined by the speed of servo motor 1.

[0072] Step 2, working advance: the electromagnet YV4 is energized, and the pressure oil flows to the P-B port of the proportional reversing valve 4, and flows from the B port to the upper chamber of the speed-increasing oil cylinder 11, and continues to play the role of working advance; the lower chamber of the speed-increasing oil cylinder 11 flows back to the oil tank 14 through the back pressure valve 6-the A port-T port of the proportional reversing valve 4, and finally flows to the oil tank 14; at this time, the working advance speed is determined by the speed of the servo motor 1. This working advance speed is enabled under a specific small load range, and only the upper chamber of the speed-increasing oil cylinder 11 is used as the actuator of the power output, so as to improve the efficiency and set the function.

[0073] Step 3, maintaining pressure: the same as step 2; only the speed and torque of the servo motor 1 need to be adjusted to achieve pressure maintenance.

[0074] Step 4, pressure relief: the electromagnet YV3 is energized, and the pressure oil in the upper chamber of the speed increasing cylinder 11 simultaneously flows in the opposite direction through the A-T ports of the proportional reversing valve 4 and flows back to the oil tank 14; at this time, the upper chamber reaches the unloading condition.

[0075] Step 5, return stroke: electromagnet YV3 is energized, and the pressure oil only flows through P-A of proportional reversing valve 4-fast lower valve 7-lower chamber of speed-increasing cylinder 11, upper chamber of speed-increasing cylinder 11-filling valve 10-oil tank 14. At this time, the lower chamber of speed-increasing cylinder 11 drives the piston to return under the action of pressure oil; the return speed of the machine tool can be increased.

[0076] Step 6, stop: all electromagnets are de-energized, servo motor 1 stops rotating, and the machine tool is in a stationary state.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydraulic system of an electro-hydraulic numerically controlled synchronous bending machine, comprising a servo motor (1), a servo pump (2) and an oil tank (14), characterized in that: The output end of the servo motor (1) is fixedly connected to the rotating part of the servo pump (2), the oil suction port of the servo pump (2) is connected to the oil outlet of the oil tank (14), the oil discharge port of the servo pump (2) is connected to two sets of hydraulic speed control systems, and the two sets of hydraulic speed control systems are both connected to the oil return port of the oil tank (14); The hydraulic speed regulating system comprises a main pressure relief valve (3), a proportional reversing valve (4), a safety valve (5), a back pressure valve (6), a quick lowering valve (7), a two-position four-way reversing valve 1 (8), a two-position four-way reversing valve 2 (9), a filling valve (10), a speed increasing cylinder (11), a throttle hole 1 (12) and a throttle hole 2 (13); The oil discharge port of the servo pump (2) is connected to the proportional reversing valve (4) and the main pressure relief valve (3); The proportional reversing valve (4) is connected to the oil tank (14), the quick-down valve (7), the main pressure relief valve (3), the throttle hole 1 (12), the throttle hole 2 (13), the two-position four-way reversing valve 2 (9), the two-position four-way reversing valve 1 (8), and the speed-increasing oil cylinder (11), and the main pressure relief valve (3) is connected to the two-position four-way reversing valve 2 (9) and the oil tank (14); The lower chamber oil port of the back pressure valve (6) is connected to the throttle hole 2 (13), the throttle hole 1 (12), the oil tank (14), the safety valve (5), the filling valve (10), and the two-position four-way reversing valve 1 (8); the upper chamber oil port of the back pressure valve (6) is connected to the two-position four-way reversing valve 1 (8), the filling valve (10), the oil tank (14), the proportional reversing valve (4), the throttle hole 1 (12), the two-position four-way reversing valve 2 (9), the proportional reversing valve (4), the main pressure relief valve (3), and the lower chamber oil port of the back pressure valve (6); the filling valve (10) is connected to the main pressure relief valve (3), the oil tank (14), the two-position four-way reversing valve 2 (9), and the two-position four-way reversing valve 1 (8); The throttle hole 2 (13) is connected to the safety valve (5), the quick-release valve (7), the back pressure valve (6) and the throttle hole 1 (12).

2. The hydraulic system of the electro-hydraulic numerically controlled synchronous bending machine according to claim 1, characterized in that: The quick-down valve (7) is provided with an electromagnet YV1 for controlling the closing thereof.

3. The hydraulic system of the electro-hydraulic numerically controlled synchronous bending machine according to claim 2, characterized in that: The proportional reversing valve (4) is provided with four ports A, B, P and T. The proportional reversing valve (4) is also provided with an electromagnet YV3 and an electromagnet YV4 for controlling the communication between the A port and the P port and the T port, and between the B port and the A port and the T port.

4. The hydraulic system of the electro-hydraulic numerically controlled synchronous bending machine according to claim 3, characterized in that: The two-position four-way reversing valve 1 (8) and the two-position four-way reversing valve 2 (9) have the same structure and are both provided with four ports A, B, P and T. The two-position four-way reversing valve 1 (8) is provided with an electromagnet YV2 for controlling the connection between its A port and the P port and the T port, and between its B port and the A port and the T port. The two-position four-way reversing valve 2 (9) is provided with an electromagnet YV3 for controlling the connection between its A port and the P port and the T port, and between its B port and the A port and the T port.

5. The hydraulic system of the electro-hydraulic numerically controlled synchronous bending machine according to claim 4, characterized in that: The A port of the proportional reversing valve (4) is connected to the back pressure valve (6) and the quick lowering valve (7) through pipelines. The B port of the proportional reversing valve (4) is connected to the oil return port of the oil tank (14), the upper chamber oil port of the speed increasing cylinder (11), the P port of the two-position four-way reversing valve (8), the B port of the two-position four-way reversing valve (8), the P port of the two-position four-way reversing valve (9), the main pressure relief valve (3), the P port of the proportional reversing valve (4), the throttle hole (12), the throttle hole (13), and the oil discharge port of the servo pump (2). The P port of the proportional reversing valve (4) is connected to the servo pump (2). The oil discharge port of the pump (2) is connected, the T port of the proportional reversing valve (4) is connected to the safety valve (5), the main pressure relief valve (3), the T port of the second two-position four-way reversing valve (9), and the filling valve (10) through a pipeline, the B port of the first two-position four-way reversing valve (8) is connected to the upper chamber oil port of the speed increasing cylinder (11), the oil return port of the oil tank (14), and the P port of the second two-position four-way reversing valve (9), the B port of the second two-position four-way reversing valve (9) is connected to the filling valve (10), and the T port of the second two-position four-way reversing valve (9) is connected to the filling valve (10) and the oil tank (14).

6. A dual-speed working mode of an electro-hydraulic numerically controlled synchronous bending machine, using the hydraulic system of the electro-hydraulic numerically controlled synchronous bending machine of claim 5, characterized in that: There are standard mode and fast mode.

7. The dual-speed working mode of the electro-hydraulic numerically controlled synchronous bending machine according to claim 6 is characterized in that: The standard mode uses the following control steps: Step 1, fast lowering: the electromagnets YV1 and YV4 are energized, the servo motor (1) drives the servo pump (2) to rotate, the oil suction port of the servo pump (2) is connected to the oil tank (14), and the main pressure oil flows to the P-B port of the proportional reversing valve (4) without exceeding the pressure setting of the main pressure relief valve (3), and flows from the B port to the upper chamber of the speed-increasing oil cylinder (11); the oil port of the lower chamber of the speed-increasing oil cylinder (11) flows back to the oil tank (14) through the fast lowering valve (7)-the A port-the T port of the proportional reversing valve (4), and the filling valve (10) is normally open. Under the action of the deadweight of the slide plate, the speed-increasing oil cylinder (11) quickly absorbs oil from the oil tank (14) and flows through the filling valve (10); Step 2, working advance: the electromagnets YV2, YV4, and YV5 are energized, and the pressure oil is divided into three branches: the first branch flows to the P-B port of the proportional reversing valve (4), and then flows from the B port to the upper chamber of the speed increasing cylinder (11), playing the role of working advance of the upper chamber; The second branch flows to the first two-position four-way reversing valve (8), passes through the P—B—upper chamber of the speed-increasing oil cylinder (11), and plays the role of advancing the upper chamber of the speed-increasing oil cylinder (11); the third branch flows to the second two-position four-way reversing valve (9), the P—B—liquid filling valve (10), and closes the liquid filling valve (10); the lower chamber of the speed-increasing oil cylinder (11) flows back to the oil tank (14) through the back pressure valve (6)—the A port—the T port of the proportional reversing valve (4), and finally flows to the oil tank (14); Step 3, pressure maintenance: same as step 2; Step 4, pressure relief: the electromagnets YV2, YV3, and YV5 are energized, and the pressure oil in the upper chamber of the speed-increasing oil cylinder (11) flows in the reverse direction through the two-position four-way reversing valve 1 (8) and the A port to the T port of the proportional reversing valve (4) to flow back to the oil tank (14). At the same time, the pressure oil in the upper chamber of the speed-increasing oil cylinder (11) flows in the reverse direction through the A port to the T port of the proportional reversing valve (4) to flow back to the oil tank (14). The filling valve (10) controls the pressure oil flow to flow in the reverse direction through the two-position four-way reversing valve 2 (9) and flow from B to T to the oil tank (14). The filling valve (10) is opened to connect the upper chamber of the speed-increasing oil cylinder (11) with the oil tank (14), and the pressure oil flows back to the oil tank (14). At this time, the pressure relief condition of the upper chamber of the speed-increasing oil cylinder (11) is completed. Step 5, return stroke: the electromagnet YV3 is energized, and the pressure oil only flows through the P-A of the proportional reversing valve (4)-the quick lower valve (7)-the lower chamber of the speed-increasing oil cylinder (11), the upper chamber of the speed-increasing oil cylinder (11)-the filling valve (10)-the oil tank (14), and the lower chamber of the speed-increasing oil cylinder (11) drives the piston to return stroke under the action of the pressure oil; Step 6, stop: All electromagnets are de-energized, the servo motor (1) stops rotating, and the machine tool is in a stationary state.

8. The dual-speed working mode of the electro-hydraulic CNC synchronous bending machine according to claim 7 is characterized in that: The fast mode uses the following control steps: Step 1, fast lowering: the electromagnet YV4 is energized, the servo motor (1) drives the servo pump (2) to rotate, the oil suction port of the servo pump (2) is connected to the oil tank (14), and the main pressure oil flows to the P-B port of the proportional reversing valve (4) without exceeding the pressure setting of the main pressure relief valve (3), and flows from the B port to the upper chamber of the speed-increasing oil cylinder (11), thereby accelerating the fast lowering speed of the speed-increasing oil cylinder (11); the oil port of the lower chamber of the speed-increasing oil cylinder (11) flows back to the oil tank (14) from the back pressure valve (6) - the A port - the T port of the proportional reversing valve (4); Step 2, working forward: the electromagnet YV4 is energized, and the pressure oil flows to the P-B port of the proportional reversing valve (4), and flows from the B port to the upper chamber of the speed-increasing oil cylinder (11), and the lower chamber of the speed-increasing oil cylinder (11) flows back to the oil tank (14) through the back pressure valve (6)-the A port-the T port of the proportional reversing valve (4), and finally flows to the oil tank (14); Step 3, pressure maintenance: same as step 2; Step 4, pressure relief: the electromagnet YV3 is energized, and the pressure oil in the upper chamber of the speed increasing cylinder (11) simultaneously flows in the opposite direction through the A-T ports of the proportional reversing valve (4) and flows back to the oil tank (14), and the pressure oil flows back to the oil tank (14); Step 5, return stroke: the electromagnet YV3 is energized, and the pressure oil only flows through the P-A of the proportional reversing valve (4)-the quick lower valve (7)-the lower chamber of the speed-increasing oil cylinder (11), the upper chamber of the speed-increasing oil cylinder (11)-the filling valve (10)-the oil tank (14), and the lower chamber of the speed-increasing oil cylinder (11) drives the piston to return stroke under the action of the pressure oil; Step 6, stop: All electromagnets are de-energized and the servo motor (1) stops rotating.

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