Hydraulic control system of hydraulic machine

Abstract

The utility model discloses a hydraulic control system of a hydraulic machine. The hydraulic control system comprises a setting unit, an execution unit, a calculation unit and a power unit. The power unit comprises a motor, a hydraulic pump, a power valve, a proportional valve, a pressure valve, a pilot overflow valve and a first displacement sensor. According to the hydraulic control system of the hydraulic machine, the displacement of the hydraulic pump can be adjusted in a stepless mode through the proportional valve on the hydraulic pump and a closed loop of the first displacement sensor, and the main cylinder can machine a workpiece according to the set working speed in cooperation with the rotating speed of the motor; and when the main cylinder needs to be pressurized, stepless closed-loop adjustment of the pressure can be achieved through mutual cooperation of the pilot overflow valve, the motor and the first displacement sensor, and finally efficient and high-precision displacement control and pressure control over the main cylinder are achieved.

Description

Technical Field

[0001] The utility model belongs to the field of hydraulic press control, and particularly relates to a hydraulic control system for a hydraulic press. Background Art

[0002] A hydraulic press is a machine that uses liquid as the working medium and is made according to Pascal's principle to transfer energy to achieve various processes. A hydraulic press generally consists of three parts: the machine itself (mainframe), the power system, and the hydraulic control system.

[0003] At present, the hydraulic control systems used in hydraulic presses mainly have two control methods: valve control and pump control. Valve control uses hydraulic valves to control the speed and pressure of the main cylinder. This kind of hydraulic system has a high cost and low energy conversion. Although theoretically valve control can achieve higher-precision control, compared with pump control, it is more difficult to control. If not handled well technically, its precision is even lower than that of pump control. Content of the Utility Model

[0004] The purpose of the utility model is to provide a hydraulic control system for a hydraulic press, which can achieve efficient and high-precision displacement control and pressure control of the main cylinder.

[0005] To achieve the above-mentioned utility model purpose, the technical solution adopted by the utility model is as follows:

[0006] The hydraulic control system of the hydraulic press includes:

[0007] A setting unit for setting the working parameters of the main cylinder;

[0008] An execution unit including a main cylinder; the main cylinder is used to process workpieces according to the set working parameters;

[0009] A power unit including a motor, a hydraulic pump, a power valve, a proportional valve, a pressure valve, a pilot overflow valve, and a first displacement sensor;

[0010] A calculation unit for calculating the corresponding displacement of the hydraulic pump according to the set working parameters of the main cylinder;

[0011] The hydraulic pump is used to discharge hydraulic oil after starting;

[0012] The motor is used to control the start of the corresponding number of hydraulic pumps according to the calculated displacement of the hydraulic pump;

[0013] The power valve is used to control the output power of the motor;

[0014] The proportional valve is used to control the displacement of the hydraulic pump;

[0015] The pressure valve is used to obtain the pressure value of the hydraulic pump when discharging hydraulic oil;

[0016] The pilot relief valve is used to control the magnitude of the pressure value of the hydraulic pump under oil pressure;

[0017] The first displacement sensor is used to obtain the ratio of the current displacement and the maximum displaceable amount of the hydraulic pump.

[0018] A hydraulic control system for a hydraulic press according to the present utility model can steplessly adjust the displacement of the hydraulic pump through a closed loop of a proportional valve and a first displacement sensor on the hydraulic pump, and cooperate with the rotational speed of the motor, so that the main cylinder can process the workpiece at a set working speed; and when the main cylinder needs to be pressurized, the mutual cooperation of the pilot relief valve, the motor, and the first displacement sensor can achieve stepless closed-loop adjustable pressure, and finally achieve efficient and high-precision displacement control and pressure control of the main cylinder.

[0019] Preferably, the hydraulic control system further includes a switch unit; the switch unit includes a solenoid valve; the solenoid valve is used to control the connection or disconnection between the power unit and the main cylinder.

[0020] A hydraulic control system for a hydraulic press according to the present utility model can supply oil to the main cylinder by any number of hydraulic pumps by setting a solenoid valve.

[0021] Preferably, the setting unit is further used to set the rotational speed of the motor; the motor is further used to control the rotation of the hydraulic pump at the set rotational speed.

[0022] A hydraulic control system for a hydraulic press according to the present utility model can make the hydraulic pump rotate at the set rotational speed by setting the rotational speed of the motor through the setting unit.

[0023] Preferably, the switch unit further includes a two-way valve, and the two-way valve is arranged between the main cylinder and the hydraulic pump; the solenoid valve is further used to control the opening or closing of the two-way valve; the hydraulic pump is further used to input hydraulic oil to the main cylinder when it is started by the motor and the two-way valve is opened.

[0024] A hydraulic control system for a hydraulic press according to the present utility model makes the hydraulic pump input hydraulic oil to the main cylinder only when it is started by the motor and the two-way valve is opened by setting the two-way valve as the connection switch between the main cylinder and the hydraulic pump.

[0025] Preferably, the hydraulic control system further includes a second displacement sensor; the second displacement sensor is used to obtain displacement data during the downward pressing process of the main cylinder; the main cylinder is further used to press the workpiece according to the hydraulic oil input by the hydraulic pump.

[0026] A hydraulic control system for a hydraulic press according to the present utility model can intuitively reflect the working condition of the main cylinder by setting a second displacement sensor to obtain displacement data during the downward pressing process of the main cylinder.

[0027] Preferably, the setting unit further includes a human-machine interface; the human-machine interface is used to set the working speed and working pressure of the master cylinder.

[0028] Preferably, the human-machine interface is further used to set the rotational speed of the motor; the rotational speed of the motor set by the human-machine interface is ≥ 500 r / min.

[0029] Preferably, the power unit further includes a two-way cartridge valve; the output end of the hydraulic pump is connected to the solenoid valve through the two-way cartridge valve.

[0030] Preferably, the number of the power units is several; in each power unit, the input end of the hydraulic pump is connected to the motor; the output end of the hydraulic pump is connected to the input end of the two-way cartridge valve, and the output end of the two-way cartridge valve is connected to the solenoid valve.

[0031] Preferably, let the maximum displacement of the hydraulic pump be y ml / rev; the displacement range of the hydraulic pump controlled by the proportional valve is 0 - y ml / rev.

[0032] Advantageous effects:

[0033] For the hydraulic control system of a hydraulic press of the present utility model, the hydraulic control system can steplessly adjust the displacement of the hydraulic pump through the closed loop of the proportional valve and the first displacement sensor on the hydraulic pump, and cooperate with the rotational speed of the motor, so that the master cylinder can process the workpiece at the set working speed; and when the master cylinder needs to be pressurized, the mutual cooperation of the pilot overflow valve, the motor and the first displacement sensor can realize stepless closed-loop adjustable pressure; after the hydraulic control method is applied to the hydraulic control system of the present utility model, it can perform optimal control on multiple hydraulic pumps according to the set working speed and working pressure of the master cylinder, and finally realize high-efficiency and high-precision displacement control and pressure control of the master cylinder. Description of the drawings

[0034] Figure 1 Shown is the structural diagram of a hydraulic control system of a hydraulic press in an embodiment;

[0035] Figure 2 Shown is the flow chart of a hydraulic control method of a hydraulic press in an embodiment;

[0036] Figure 3 Shown is the first control logic diagram of a hydraulic control method of a hydraulic press in an embodiment;

[0037] Figure 4 Shown is the second control logic diagram of a hydraulic control method of a hydraulic press in an embodiment.

[0038] Reference numerals

[0039] 1. Motor; 2. Hydraulic pump; 3. Power valve; 4. Proportional valve; 5. First displacement sensor; 6. Pressure valve; 7. Pilot relief valve; 8. Main cylinder; 9. Second displacement sensor; 10. Workpiece; 11. Solenoid valve; 12. Two-way valve; 13. One-two-way cartridge valve. Detailed implementation mode

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation modes of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings, and other implementation modes can also be obtained.

[0041] The technical solutions of the present invention will be introduced in detail below with specific embodiments.

[0042] Embodiment 1

[0043] As Figure 1 shown, the hydraulic control system of a hydraulic press in this embodiment includes:

[0044] A setting unit for setting the working parameters of the main cylinder 8;

[0045] An execution unit including the main cylinder 8; the main cylinder 8 is used to process the workpiece 10 according to the set working parameters;

[0046] A power unit including a motor 1, a hydraulic pump 2, a power valve 3, a proportional valve 4, a pressure valve 6, a pilot relief valve 7, and a first displacement sensor 5;

[0047] A calculation unit for calculating the corresponding displacement of the hydraulic pump 2 according to the set working parameters of the main cylinder 8;

[0048] The hydraulic pump 2 is used to discharge hydraulic oil after starting;

[0049] The motor 1 is used to control the start of the corresponding number of hydraulic pumps 2 according to the calculated displacement of the hydraulic pump 2;

[0050] The power valve 3 is used to control the output power of the motor 1;

[0051] The proportional valve 4 is used to control the displacement of the hydraulic pump 2;

[0052] The pressure valve 6 is used to obtain the pressure value of the hydraulic pump 2 when discharging hydraulic oil;

[0053] The pilot relief valve 7 is used to control the magnitude of the pressure value of the hydraulic pump 2;

[0054] The first displacement sensor 5 is used to obtain the ratio of the current displacement to the maximum displaceable amount of the hydraulic pump 2.

[0055] For the hydraulic control system of a hydraulic press in this embodiment, the displacement of the hydraulic pump 2 can be steplessly adjusted through the closed-loop of the proportional valve 4 and the first displacement sensor 5 on the hydraulic pump 2. Cooperating with the rotational speed of the motor 1, the main cylinder 8 can process the workpiece 10 at a set working speed; and when the main cylinder 8 needs to be pressurized, the mutual cooperation of the pilot overflow valve 7, the motor 1, and the first displacement sensor 5 can achieve stepless closed-loop adjustable pressure, and finally achieve efficient and high-precision displacement control and pressure control of the main cylinder 8.

[0056] Preferably, the hydraulic control system further includes a switch unit; the switch unit includes a solenoid valve 11; the solenoid valve 11 is used to control the connection or disconnection between the power unit and the main cylinder 8.

[0057] For the hydraulic control system of a hydraulic press in this embodiment, by setting the solenoid valve 11, the main cylinder 8 can be supplied with oil by any number of hydraulic pumps 2.

[0058] Preferably, the setting unit is further used to set the rotational speed of the motor 1; the motor 1 is further used to control the rotation of the hydraulic pump 2 at the set rotational speed.

[0059] For the hydraulic control system of a hydraulic press in this embodiment, by setting the rotational speed of the motor 1 through the setting unit, the hydraulic pump 2 can rotate at the set rotational speed.

[0060] Preferably, the switch unit further includes a two-way valve 12, and the two-way valve 12 is arranged between the main cylinder 8 and the hydraulic pump 2; the solenoid valve 11 is further used to control the opening or closing of the two-way valve 12; the hydraulic pump 2 is further used to input hydraulic oil to the main cylinder 8 when it is started by the motor 1 and the two-way valve 12 is opened.

[0061] For the hydraulic control system of a hydraulic press in this embodiment, by setting the two-way valve 12 as the connection switch between the main cylinder 8 and the hydraulic pump 2, the hydraulic pump 2 will input hydraulic oil to the main cylinder 8 only when it is started by the motor 1 and the two-way valve 12 is opened.

[0062] Preferably, the hydraulic control system further includes a second displacement sensor 9; the second displacement sensor 9 is used to obtain the displacement data during the downward pressing process of the main cylinder 8; the main cylinder 8 is further used to press the workpiece 10 according to the hydraulic oil input by the hydraulic pump 2.

[0063] For the hydraulic control system of a hydraulic press in this embodiment, by setting the second displacement sensor 9 to obtain the displacement data during the downward pressing process of the main cylinder 8, the working condition of the main cylinder 8 can be intuitively reflected.

[0064] Preferably, the setting unit further includes a human-machine interface; the human-machine interface is used to set the working speed and working pressure of the main cylinder 8.

[0065] Preferably, the human-machine interface is also used to set the rotational speed of the motor 1, and the rotational speed of the motor 1 set by the human-machine interface is ≥ 500 r / min.

[0066] Preferably, the power unit further includes a one-two-way cartridge valve 13; the output end of the hydraulic pump 2 is connected to the two-way valve 12 through the one-two-way cartridge valve 13.

[0067] Preferably, the number of power units is several; in each power unit, the input end of the hydraulic pump 2 is connected to the motor 1; the output end of the hydraulic pump 2 is connected to the input end of the one-two-way cartridge valve 13, and the output end of the one-two-way cartridge valve 13 is connected to the two-way valve 12.

[0068] Preferably, the displacement range of the hydraulic pump 2 controlled by the proportional valve 4 is 0 to y ml / rev; the maximum displacement of the hydraulic pump 2 is y ml / rev. Where y is the maximum displacement of the hydraulic pump in this embodiment, and it can be 125 mL / r, 180 mL / r or 250 mL / r.

[0069] Specifically, the hydraulic control system of this embodiment can steplessly adjust the displacement of the hydraulic pump 2, that is, the adjustment range of the displacement of the hydraulic pump 2 is from 0 to the maximum value.

[0070] Specifically, the hydraulic control system of this embodiment can steplessly adjust the pressure value of the hydraulic pressure received by the hydraulic pump 2, that is, the adjustment range of the pressure value of the hydraulic pressure received by the hydraulic pump 2 is from 0 to the maximum value.

[0071] Specifically, the first displacement sensor 5 of this embodiment can real-time feedback the displacement ratio of the hydraulic pump 2, and the second displacement sensor 9 can real-time feedback the downward displacement data of the master cylinder 8, making the control process of the hydraulic control system more intuitive, thereby improving the control accuracy of the hydraulic control system.

[0072] Specifically, the setting unit of this embodiment further includes a human-machine interface, which is used to input the working speed and working pressure of the master cylinder 8, and can also set the rotational speed of the motor 1.

[0073] Specifically, after the solenoid valve 11 of this embodiment is energized, it controls the two-way valve 12 to open, so that the master cylinder 8 is connected to the hydraulic pump 2.

[0074] Specifically, the motor 1 of this embodiment is a servo motor 1, which is the center of the power source and can convert electrical energy into mechanical energy; the hydraulic pump 2 of this embodiment is a variable hydraulic pump 2, and the power valve 3, proportional valve 4, pressure valve 6 and pilot overflow valve 7 form a hydraulic system. The motor 1 can drive the variable hydraulic pump 2 to rotate to output hydraulic energy to the hydraulic system, that is, discharge hydraulic oil.

[0075] Further, the function of the power valve 3 in this embodiment is to ensure that the power of the motor 1 does not overload during the process of the hydraulic pump 2 outputting hydraulic energy to the hydraulic system; when the motor 1 reaches its rated power, the power valve 3 will reduce the displacement of the hydraulic pump 2 to ensure that the motor 1 does not overload.

[0076] Further, the function of the proportional valve 4 in this embodiment is to control the displacement of the variable hydraulic pump 2, and the implementation method is that the proportional valve 4 and the displacement sensor are used for closed-loop control of the displacement size of the variable hydraulic pump 2.

[0077] Further, the functions of the pressure valve 6 and the pilot overflow valve 7 in this embodiment are to achieve proportional control of the maximum output pressure of the hydraulic pump 2, and the control method is to control the pressure of the pilot overflow valve 7.

[0078] Furthermore, the variable hydraulic pump 2 can implement power limit control, proportional displacement control, and proportional pressure control, and the priority order is proportional pressure control, power limit control, and proportional displacement control. When working normally, the motor 1 drives the hydraulic pump 2 to rotate to supply oil to the main cylinder 8. Among them, the solenoid valve 11 in the main circuit has the function of the total switch of the whole system. Only when the solenoid valve 11 is energized, the oil of the hydraulic pump 2 can flow to the main cylinder 8 to push the main cylinder 8 to press against the workpiece 10, and the workpiece 10 is deformed under the action of pressure.

[0079] Embodiment Two

[0080] This embodiment provides a hydraulic control method for a hydraulic press, which is applied to the hydraulic control system of the hydraulic press in Embodiment One. As Figures 2 to 4 shown, the hydraulic control method in this embodiment includes the following steps:

[0081] Step S1. Set the set speed N 设 of the motor 1 设 and the working speed V 设 of the main cylinder 8, and calculate the required hydraulic pump displacement V0 when the main cylinder 8 reaches V

[0082] Step S2. Calculate the average speed N0 of the n motors 1 when the n hydraulic pumps 2 work to reach the required displacement V0, and determine whether the speed N0 is greater than the set speed N 设 , if so, go to Step S3; if not, go to Step S4;

[0083] Step S3. Control the motors 1 of the n hydraulic pumps 2 to start working at the speed N0, and at the same time, the solenoid valve 11 controls the n hydraulic pumps 2 to communicate with the main cylinder 8, and then enter Step S5;

[0084] Step S4. Calculate the average speed N1 of the n - 1 motors 1 when the n - 1 hydraulic pumps 2 are working and the required displacement V0 is reached, and determine whether the speed N1 is greater than the set speed N 设 , if so, control the motors 1 of the n - 1 hydraulic pumps 2 to start working at the speed N1, and at the same time, the solenoid valve 11 controls the n - 1 hydraulic pumps 2 to communicate with the main cylinder 8, then enter step S5; if not, continue to calculate the average speed N2 of the n - 2 motors 1 when the n - 2 hydraulic pumps 2 are working and the required displacement V0 is reached......, until the average speed N of the n - m motors 1 when the n - m hydraulic pumps 2 are working and the required displacement V0 is reached m is still less than N 设 , and at the same time n - m = 1, then control the motor 1 of 1 hydraulic pump 2 to start working at the speed N m and at the same time, the solenoid valve 11 controls 1 hydraulic pump 2 to communicate with the main cylinder 8; where n≥3, 1≤m≤n - 1;

[0085] Step S5. End.

[0086] A hydraulic control method of a hydraulic press in this embodiment, after being applied to the above - mentioned hydraulic control system, enables the hydraulic control system to perform optimal control on multiple hydraulic pumps 2 according to the set working speed of the main cylinder 8.

[0087] Preferably, the hydraulic control method further includes:

[0088] Set the working pressure F0 of the main cylinder 8, and obtain the maximum pressure F that can be reached when a single hydraulic pump 2 is working max ; if F0 < F max , then the motor 1 starts the first hydraulic pump 2 at the rated speed, and the pressure valve 6 obtains the pressure value F1 that gradually increases with the displacement during the start - up process of this hydraulic pump 2, and F1∈[0,F max ; during this process, if the control relief valve detects that F1 = F0, then control the relief valve to maintain the pressure value of the hydraulic pump 2 at F1.

[0089] Preferably, the hydraulic control method further includes:

[0090] If F0 > F max , then calculate that the number of hydraulic pumps 2 required to reach F0 is x, the motor 1 starts the first hydraulic pump 2 at the rated speed, and when the first displacement sensor 5 of the first hydraulic pump 2 is at the maximum value, the motor 1 continues to start the second hydraulic pump 2 at the rated speed until the number of started hydraulic pumps 2 is x.

[0091] Preferably, the hydraulic control method further includes:

[0092] During the process of starting the x-th hydraulic pump 2 by the motor 1 at the rated speed, when the total pressure of the x hydraulic pumps 2 reaches F0, it is determined whether the first displacement sensor 5 of the x-th hydraulic pump 2 is at the maximum value. If so, the motor 1 is maintained at the rated speed; if not, the speed of the motor 1 is reduced, and at the same time, the overflow valve is controlled to maintain the total pressure of the x hydraulic pumps 2 at F0.

[0093] A hydraulic control method of a hydraulic press in this embodiment, after being applied to the above hydraulic control system, enables the hydraulic control system to perform optimal control on multiple hydraulic pumps 2 according to the set working pressure of the main cylinder 8.

[0094] Preferably, when calculating the required displacement of the hydraulic pump in steps S1, S2, and S4, the following relational expressions are included:

[0095]

[0096] Where the working speed of the main cylinder is V 油 , the cylinder diameter of the main cylinder is D, the displacement of the hydraulic pump is V 泵 , the efficiency of the hydraulic pump is η b , the speed of the motor is N 电 .

[0097] Specifically, the hydraulic pump 2 in this embodiment can be provided with countless ones, and through the hydraulic control system combined with the hydraulic control method, optimal control of countless hydraulic pumps 2 can be achieved.

[0098] Specifically, the efficiency of the hydraulic pump 2 in this embodiment is an inherent characteristic of the hydraulic pump 2, which is mainly related to the working pressure of the pump and the displacement state of the pump. It can be simply considered that under the same pressure, the larger the displacement of the hydraulic pump 2, the higher the efficiency.

[0099] Specifically, the speed of the motor 1 in this embodiment can be adjusted steplessly and selected from 0 to the maximum speed; however, due to the reason of the hydraulic pump 2, it is generally set not less than 500 r / min. Among them, the set speed N of the motor 1 set in step S1 of this embodiment 设 is 500 r / min.

[0100] Specifically, the displacement of the hydraulic pump 2 in this embodiment can be adjusted steplessly and selected from 0 to 100%.

[0101] Specifically, the main cylinder 8 in this embodiment sets a fixed speed according to the process requirements of the workpiece 10, and the hydraulic control system sets the speed of the servo motor 1 and the displacement of the hydraulic pump 2 according to the control logic as Figure 3 shown, and finally meets the speed requirements of the main cylinder 8.

[0102] Specifically, when the main cylinder 8 in this embodiment sets the maximum pressing force according to the process requirements of the workpiece 10, the hydraulic control system is in accordance with asFigure 4 The control logic shown sets the rotational speed of the servo motor 1 and the displacement of the hydraulic pump 2, ultimately meeting the pressing force requirement of the main cylinder 8.

[0103] Furthermore, after the main cylinder 8 sets a speed and maximum pressure display that meet the process requirements, the hydraulic pump 2 first calculates an optimal combination of the rotational speed of the motor 1 and the displacement of the hydraulic pump 2 according to the Figure 3 logic. The motor 1 and the hydraulic pump 2 are started and the solenoid valve 11 is energized. The hydraulic pump 2 advances towards the workpiece 10 at a preset speed.

[0104] Even further, the hydraulic press also sets a maximum pressing force for the main cylinder 8 (pressing force = area of the main cylinder 8 * hydraulic system pressure). The pressure test of the hydraulic system is set through the pilot overflow valve 7 of the hydraulic pump 2 (by default, a 0 - 10V analog voltage corresponds to the minimum pressure to the maximum pressure). The hydraulic pressure of the main cylinder 8 gradually increases during the process of pressing towards the workpiece 10 until the maximum limit value, but will not exceed this value, that is, pressure protection is achieved.

[0105] The above has elaborated in detail on the embodiments of a hydraulic control system of a hydraulic press provided by the present utility model. Specific examples are used herein to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the core idea of the present utility model. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A hydraulic control system for a hydraulic press, which is used for processing workpieces, characterized in that: It includes: A setting unit for setting the working parameters of the main cylinder (8); An execution unit including the main cylinder (8); the main cylinder (8) is used for processing workpieces according to the set working parameters; A power unit including a motor (1), a hydraulic pump (2), a power valve (3), a proportional valve (4), a pressure valve (6), a pilot overflow valve (7), and a first displacement sensor (5); A calculation unit for calculating the displacement of the corresponding hydraulic pump (2) according to the set working parameters of the main cylinder (8); The hydraulic pump (2) is used for discharging hydraulic oil after starting; The motor (1) is used for controlling the start of the corresponding number of hydraulic pumps (2) according to the calculated displacement of the hydraulic pump (2); The power valve (3) is used for controlling the output power of the motor (1); The proportional valve (4) is used for controlling the displacement of the hydraulic pump (2); The pressure valve (6) is used for obtaining the pressure value of the hydraulic pump (2) when discharging hydraulic oil; The pilot overflow valve (7) is used for controlling the magnitude of the pressure of the hydraulic pump (2); The first displacement sensor (5) is used for obtaining the ratio of the current displacement and the maximum displaceable amount of the hydraulic pump (2).

2. The hydraulic control system according to claim 1, characterized in that The hydraulic control system further includes a switch unit; the switch unit includes a solenoid valve (11); the solenoid valve (11) is used for controlling the connection or disconnection between the power unit and the main cylinder (8).

3. The hydraulic control system according to claim 1, characterized in that, The setting unit is further used for setting the rotation speed of the motor (1); the motor (1) is further used for controlling the rotation of the hydraulic pump (2) at the set rotation speed.

4. The hydraulic control system according to claim 2, wherein The switch unit further includes a two-way valve (12), and the two-way valve (12) is arranged between the main cylinder (8) and the hydraulic pump (2); the solenoid valve (11) is further used for controlling the opening or closing of the two-way valve (12); the hydraulic pump (2) is further used for inputting hydraulic oil to the main cylinder (8) when started by the motor (1) and the two-way valve (12) is opened.

5. The hydraulic control system according to claim 1, characterized in that, The hydraulic control system further includes a second displacement sensor (9); the second displacement sensor (9) is used for obtaining displacement data during the downward pressing process of the main cylinder (8); the main cylinder (8) is further used for pressing the workpiece according to the hydraulic oil input by the hydraulic pump (2).

6. The hydraulic control system according to claim 1, wherein The setting unit further includes a human-machine interface; the human-machine interface is used for setting the working speed and working pressure of the main cylinder (8).

7. The hydraulic control system according to claim 6, wherein The human-machine interface is further used for setting the rotation speed of the motor (1), and the rotation speed of the motor (1) set by the human-machine interface ≥ 500 r / min.

8. The hydraulic control system according to claim 4, wherein The power unit further includes a two-way cartridge valve (13); the output end of the hydraulic pump (2) is connected to the two-way valve (12) through the two-way cartridge valve (13).

9. The hydraulic control system according to claim 8, characterized in that, The number of the power units is several; in each power unit, the input end of the hydraulic pump (2) is connected to the motor (1); the output end of the hydraulic pump (2) is connected to the input end of the two-way cartridge valve (13), and the output end of the two-way cartridge valve (13) is connected to the two-way valve (12).

10. The hydraulic control system according to any one of claims 1 to 8, characterized in that it is provided with The maximum displacement of the hydraulic pump (2) is y ml / rev; the proportional valve (4) controls the displacement range of the hydraulic pump (2) from 0 to y ml / rev.

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