Hydraulic system for extruding machine and using method of hydraulic system

Abstract

The invention discloses a hydraulic system for an extruding machine and a using method of the hydraulic system, and relates to the technical field of hydraulic mechanical energy saving.The hydraulic system for the extruding machine comprises an electro-hydraulic servo control mechanism, a servo driver and an extruding machine PLC, the electro-hydraulic servo control mechanism comprises a permanent magnet synchronous servo motor and an oil pump, and the servo driver is connected with the permanent magnet synchronous servo motor; the number of the permanent magnet synchronous servo motors is four, the output ends of the four permanent magnet synchronous servo motors are in transmission connection with the input end of the oil pump through couplings, servo controllers are installed on the permanent magnet synchronous servo motors, and the servo controllers are electrically connected with servo drivers in a bidirectional mode. According to the scheme, the problems that an asynchronous motor is usually adopted as a driving component in an existing hydraulic assembly of the extruding machine, but under the non-full-load working condition of the asynchronous motor, a system relieves pressure through an overflow valve, invalid energy consumption is likely to be caused, oil pressure control is not accurate, and the rejection rate is increased are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy-saving hydraulic machinery, in particular to a hydraulic system for an extruder and a method of using the system. Background Art

[0002] Aluminum profile extrusion press is a horizontal structure single-action forward extrusion equipment based on hydraulic drive, which is mainly used for the extrusion processing of aluminum and its alloy profiles.

[0003] Current aluminum extrusion machines, such as those disclosed in Publication No. CN117066297B, are aluminum extrusion molding machines comprising a base, a hydraulic press, a molding mechanism, and an extrusion assembly. The hydraulic press is mounted at the rear end of the base, and the extrusion assembly, which includes a shift fork disposed therein, is mounted at one end of the hydraulic press near the base. The shift fork moves within a groove defined in the extrusion assembly, thereby extending the middle portion of the extrusion assembly, which pushes the remaining material within the molding mechanism. However, existing extruder hydraulic components often use asynchronous motors as drive components. However, when the asynchronous motor is not fully loaded, the system releases pressure through the overflow valve, which easily leads to ineffective energy consumption and inaccurate oil pressure control, resulting in an increased scrap rate. To this end, we provide a hydraulic system for an extruder and a method for using the same. Summary of the Invention

[0004] The object of the present invention is to provide a hydraulic system for an extruder and a method of using the same, so as to solve the problem that the existing hydraulic components of the extruder proposed in the above background technology often use an asynchronous motor as a driving component, but when the asynchronous motor is not fully loaded, the system releases pressure through the overflow valve, which easily leads to ineffective energy consumption, and the oil pressure control is inaccurate, resulting in an increased scrap rate.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a hydraulic system for an extruder, comprising an electro-hydraulic servo control mechanism, a servo drive and an extruder PLC controller, wherein the electro-hydraulic servo control mechanism comprises a permanent magnet synchronous servo motor and an oil pump, wherein four permanent magnet synchronous servo motors are provided, and the output ends of the four permanent magnet synchronous servo motors are all connected to the input end of the oil pump through a coupling, a servo controller is installed on the permanent magnet synchronous servo motor, and the servo controller is bidirectionally electrically connected to the servo drive, a pressure sensor is installed on the oil pump, and the output end of the pressure sensor is electrically connected to the input end of the servo drive, and the output end of the extruder PLC controller is electrically connected to the input end of the servo drive.

[0006] Preferably, the servo driver has a built-in pressure-flow dual closed-loop PID algorithm module, and a braking resistor braking unit is provided on the output end of the servo driver.

[0007] Preferably, the rotor of the permanent magnet synchronous servo motor is made of neodymium iron boron magnet steel, and the rated torque is calculated based on the formula Tm=Tmax / 1.3-1.5.

[0008] Preferably, the oil pump is a gear pump or a plunger pump, and the displacement is q=L1÷2000×1000. An oil outlet is provided at the upper end of the oil pump, and an oil return port is provided at the side of the oil pump.

[0009] Preferably, the pressure sensor outputs a 0-10VDC signal to feedback the oil pressure.

[0010] Preferably, the servo drive adopts a modular design, integrates a KT4IGBT module, has a response time of ≤30ms, and supports the IEC61800-3EMC standard.

[0011] Preferably, a disc base is installed below the permanent magnet synchronous servo motor, a bottom plate is provided below the disc base, a positioning groove is provided inside the bottom plate, and both sides of the disc base are connected to the positioning groove by screws.

[0012] Preferably, a magnetic ring is provided on the outer wall of the disc-type base, and a magnetic repulsion ring is provided on the inner wall of the positioning groove.

[0013] Preferably, a support frame is installed on the outside of the base plate, the permanent magnet synchronous servo motor is connected to the coupling through a flange, a connecting piece is installed at the connection between the support frame and the flange, and the connecting piece is connected to the side of the flange through bolts.

[0014] Preferably, a method for using a hydraulic system for an extruder comprises the following steps: Step 1: The extruder PLC controller sends a flow command to the servo drive based on the preset speed N1; Step 2: After receiving the flow command, the servo driver feeds back the signal to the servo controller. At this time, when the oil pressure is not established and there is still space in the pipeline, the servo controller controls the permanent magnet synchronous servo motor to run according to the preset flow command, and operates the oil pump in a manner proportional to the flow and speed; Step 3: After the pipeline is flushed with oil, the oil body is restricted by the pipeline to establish oil pressure. The pressure sensor at the outlet of the oil pump detects the oil pressure in real time and feeds back the data to the servo drive; Step 4: After receiving the oil pressure information, the servo driver calculates the appropriate servo motor speed N2 based on the difference between the pressure command and the pressure feedback based on the PID algorithm, and feeds back the signal to the servo controller to control the permanent magnet synchronous servo motor speed to N2, so that the oil pump oil pressure is stable at a given value.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The servo driver of the present invention adopts a pressure-flow dual closed-loop PID algorithm module, so that the hydraulic system can supply oil according to the actual required flow and pressure, overcoming the high energy consumption caused by the high-pressure overflow of the ordinary quantitative pump system. In the high-flow working stage such as feeding and extrusion molding, the motor works at the set speed, while in the low-flow working stage such as preheating and shaping, the motor speed is reduced, so that the actual energy consumption is reduced by 20%-25%, and the operating temperature is effectively controlled. It solves the problem that the hydraulic components of the existing extruder often use asynchronous motors as driving components, but when the asynchronous motor is not fully loaded, the system releases pressure through the overflow valve, which easily leads to ineffective energy consumption, and the oil pressure control is not accurate, resulting in an increased scrap rate.

[0016] (2) The motor and the oil pump of the present invention are connected through a gapless coupling. The heat of the motor will not be directly transferred to the oil pump, which reduces the oil temperature and facilitates the maintenance and replacement of the oil pump. In addition, the motor can be equipped with a screw pump, an internal gear pump, a plunger pump, and a variable plunger pump, which is convenient for users to select when producing different products.

[0017] (3) The permanent magnet synchronous servo motor of the present invention is installed with a double locking structure, namely: The sides of the disc-type base of the permanent magnet synchronous servo motor are locked and fixed with the positioning slots in the base plate by screws; The connecting piece and bolts on the support frame further lock and fix the flange at the connection of the permanent magnet synchronous servo motor; This ensures the firmness of the installation of the electro-hydraulic servo control mechanism and reduces the noise generated by motor vibration to a certain extent; The disc base is placed in the positioning groove of the base plate, with a circle of magnetic ring on its outside and a circle of magnetic repulsion ring with the same polarity as it on the inner wall of the positioning groove. After the disc base is fixed in the positioning groove, the magnetic repulsion force forms a constant pre-pressure on it when the disc base is fixed. When the base is affected by the vibration of the motor, the magnetic repulsion force can respond to the micron-level high-frequency vibration, and generate reaction force faster than traditional materials such as rubber pads, thereby further suppressing the generation of noise and improving the comfort of the workshop working environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic structural diagram of the electro-hydraulic servo control mechanism of the present invention in a disassembled state; Figure 3 This is a diagram of the electric servo hydraulic system architecture of the present invention; Figure 4 This is a circuit modification diagram of the present invention; Figure 5 This is a diagram of the pressure and flow control algorithm of the servo driver of the present invention; In the figure: 1. Electro-hydraulic servo control mechanism; 101. Permanent magnet synchronous servo motor; 102. Servo controller; 103. Coupling; 104. Oil pump; 105. Oil outlet; 106. Oil return port; 107. Pressure sensor; 108. Disc base; 109. Bottom plate; 110. Support frame; 111. Magnetic ring; 112. Positioning groove; 113. Magnetic repulsion ring; 114. Connecting piece; 2. Servo drive; 3. Extruder PLC controller. DETAILED DESCRIPTION

[0019] The technical solutions 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 only part of the embodiments of the present invention, rather than all the embodiments.

[0020] See also Figure 1-5 , the present invention provides an embodiment: a hydraulic system for an extruder, including an electro-hydraulic servo control mechanism 1, a servo driver 2 and an extruder PLC controller 3, the electro-hydraulic servo control mechanism 1 including a permanent magnet synchronous servo motor 101 and an oil pump 104, four permanent magnet synchronous servo motors 101 are provided, the output ends of the four permanent magnet synchronous servo motors 101 are all transmission-connected to the input end of the oil pump 104 through a coupling 103, a servo controller 102 is installed on the permanent magnet synchronous servo motor 101, and the servo controller 102 is bidirectionally electrically connected to the servo driver 2, a pressure sensor 107 is installed on the oil pump 104, and the output end of the pressure sensor 107 is electrically connected to the input end of the servo driver 2, and the output end of the extruder PLC controller 3 is electrically connected to the input end of the servo driver 2.

[0021] Furthermore, the servo driver 2 has a built-in pressure-flow dual closed-loop PID algorithm module, and a brake resistor brake unit is provided on the output end of the servo driver 2. The servo driver 2 adopts the flow dual closed-loop algorithm module, so that the hydraulic system can supply oil according to the actual required flow and pressure, overcoming the high energy consumption caused by high-pressure overflow of the ordinary quantitative pump system. In the high-flow working stage such as feeding and extrusion molding, the motor operates at the set speed, while in the low-flow working stage such as preheating and shaping, the motor speed is reduced, so that the actual energy consumption is reduced by 20%-25%. The brake resistor unit of servo drive 2 is a discharge circuit, which has a brake resistor as the energy-consuming element of the discharge circuit. The specific selection is as follows:

[0022] Furthermore, the rotor of the permanent magnet synchronous servo motor 101 is made of neodymium iron boron magnet steel, and the rated torque is calculated based on the formula Tm=Tmax / 1.3-1.5; According to hydraulic principles, the maximum torque that the motor should provide is: Tmax=0.0159*P*q(NM), where P is the system pressure - kgf / cm2, and q is the oil pump displacement - cc / rev; Since the extruder rarely operates at full load during a working cycle, it works at high speed and low pressure or high pressure and low speed most of the time. At the same time, since the motor itself has a strong overload capacity, it is appropriate to take 1.5 times the overload capacity. Therefore, the rated torque of the motor is defined as Tm=Tmax / 1.3-1.5 for calculation.

[0023] Furthermore, the oil pump 104 is a plunger pump with a displacement of q=L1÷2000×1000. An oil outlet 105 is provided at the upper end of the oil pump 104, and an oil return port 106 is provided at the side of the oil pump 104. The two most important parameters of the extruder are pressure and flow, so when configuring a new servo system, the pressure and flow of the new servo system cannot be less than that of the original extruder; By calculating the original extruder flow rate (L1) = oil pump displacement (ml / rev) × original motor speed (R / min) × pump volumetric efficiency value ÷ 1000, when considering volumetric efficiency, the volumetric efficiency is generally = 0.9 or consult the pump sample. Under normal circumstances, the calculation does not need to consider volumetric efficiency, and its value = 1; Then calculate the new servo system oil pump displacement q (ml / rev) = L1 ÷ 2000 (new servo motor speed) × 1000).

[0024] Furthermore, the pressure sensor 107 outputs a 0-10VDC signal to feedback the oil pressure. The servo driver 2 adopts a modular design, integrates a KT4IGBT module, has a response time of ≤30ms, and supports the IEC61800-3EMC standard.

[0025] See also Figure 1 and 2 A disc base 108 is installed below the permanent magnet synchronous servo motor 101, and a bottom plate 109 is provided below the disc base 108. A positioning groove 112 is provided inside the bottom plate 109. Both sides of the disc base 108 are connected to the positioning groove 112 by screws. A magnetic ring 111 is provided on the outer wall of the disc base 108, and a magnetic repulsion ring 113 is provided on the inner wall of the positioning groove 112. A support frame 110 is installed outside the bottom plate 109. The permanent magnet synchronous servo motor 101 is connected to the coupling 103 through a flange. A connecting piece 114 is installed at the connection between the support frame 110 and the flange, and the connecting piece 114 is connected to the side of the flange by bolts. Permanent magnet synchronous servo motor 101 adopts double locking installation structure: That is, the side of the disc base 108 of the permanent magnet synchronous servo motor 101 is locked and fixed with the positioning groove 112 in the bottom plate 109 by screws; The flange at the connection of the permanent magnet synchronous servo motor 101 is further locked and fixed by using the connecting piece 114 and bolts on the support frame 110; This ensures the firmness of the installation of the electro-hydraulic servo control mechanism 1 and reduces the noise generated by the motor vibration to a certain extent; The disc base 108 is placed in the positioning groove 112, and a circle of magnetic ring 111 is provided on the outside of it. A circle of magnetic repulsion ring 113 with the same polarity is provided on the inner wall of the positioning groove 112. After the disc base 108 is fixed in the positioning groove 112, the magnetic repulsion force forms a constant pre-pressure on it when the disc base 108 is fixed. When the base is subjected to the vibration of the motor, the magnetic repulsion force can respond to the micron-level high-frequency vibration, and generate a reaction force faster than traditional materials such as rubber pads, thereby further suppressing the generation of noise.

[0026] See also Figure 1-5 A method for using a hydraulic system for an extruder comprises the following steps: Step 1: The extruder PLC controller 3 sends a flow command to the servo driver 2 based on the preset speed N1; Step 2: After receiving the flow command, the servo driver 2 feeds back a signal to the servo controller 102. At this time, when the oil pressure is not established and there is still space in the pipeline, the servo controller 102 controls the permanent magnet synchronous servo motor 101 to operate according to the preset flow command, and operates the oil pump in a manner proportional to the flow and speed; Step 3: After the pipeline is flushed with oil, the oil body is restricted by the pipeline to establish oil pressure, and the pressure sensor 107 at the outlet of the oil pump 104 detects the oil pressure in real time and feeds back the data to the servo driver 2; Step 4: After receiving the oil pressure information, the servo driver 2 calculates the appropriate servo motor speed N2 based on the difference between the pressure command and the pressure feedback based on the PID algorithm, and feeds back the signal to the servo controller 102 to control the speed of the permanent magnet synchronous servo motor 101 to N2, so that the oil pressure of the oil pump 104 is stabilized at a given value.

[0027] Taking the hydraulic system of the extruder as an example, the following are the steps for the transformation of a conventional extruder: Step 1: Dismantle the original system; Disconnect the power supply, remove the original asynchronous motor, proportional valve and star-delta starter, and record the original parameters: oil pump displacement (250cc / r high-pressure pump), system pressure 25.0MPa; Step 2: Install the servo assembly; Select a suitable servo motor that matches the original pump displacement. Use a 90kW driver (with an 8Ω brake resistor). The concentricity of the flange used for docking should be ≤50μm to ensure a gap-free connection between the motor and the oil pump. After installation, perform wiring operations. Install a circuit breaker on the power supply line. Use shielded twisted-pair cables for the signal line and add a magnetic ring for anti-interference. After wiring is completed, install the pressure sensor at the oil outlet 104 of the oil pump. Step 3: Debugging and testing: Power on the test, initialize the driver, verify EMC using Fluke instruments, perform a pressure step test (175kgf pressure response ≤30ms), and optimize the flow closed loop.

[0028] Step 4: Effect verification; Energy consumption monitoring: compare the meter data before and after the transformation to calculate whether the electricity saving rate meets the standard.

[0029] Performance test: pressure fluctuation ≤±0.5kgf, production cycle improved.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A hydraulic system for an extruder, comprising an electro-hydraulic servo control mechanism (1), a servo driver (2) and an extruder PLC controller (3), characterized in that: The electro-hydraulic servo control mechanism (1) comprises a permanent magnet synchronous servo motor (101) and an oil pump (104). Four permanent magnet synchronous servo motors (101) are provided. The output ends of the four permanent magnet synchronous servo motors (101) are all connected to the input end of the oil pump (104) through a coupling (103). A servo controller (102) is installed on the permanent magnet synchronous servo motor (101), and the servo controller (102) is bidirectionally electrically connected to the servo driver (2). A pressure sensor (107) is installed on the oil pump (104), and the output end of the pressure sensor (107) is electrically connected to the input end of the servo driver (2). The output end of the extruder PLC controller (3) is electrically connected to the input end of the servo driver (2).

2. A hydraulic system for an extruder according to claim 1, characterized in that: The servo driver (2) has a built-in pressure-flow dual closed-loop PID algorithm module, and a braking resistor braking unit is provided on the output end of the servo driver (2).

3. A hydraulic system for an extruder according to claim 2, characterized in that: The rotor of the permanent magnet synchronous servo motor (101) is made of neodymium iron boron magnet steel, and the rated torque is calculated based on the formula Tm=Tmax / 1.3-1.

5.

4. A hydraulic system for an extruder according to claim 3, characterized in that: The oil pump (104) is a gear pump or a plunger pump, and has a displacement of q=L1÷2000×1000. An oil outlet (105) is provided at the upper end of the oil pump (104), and an oil return port (106) is provided at the side of the oil pump (104).

5. A hydraulic system for an extruder according to claim 4, characterized in that: The pressure sensor (107) outputs a 0-10 VDC signal to feedback the oil pressure.

6. A hydraulic system for an extruder according to claim 5, characterized in that: The servo drive (2) adopts a modular design, integrates a KT4 IGBT module, has a response time of ≤30ms, and supports the IEC61800-3 EMC standard.

7. A hydraulic system for an extruder according to claim 6, characterized in that: A disc-type base (108) is installed below the permanent magnet synchronous servo motor (101), a bottom plate (109) is provided below the disc-type base (108), a positioning groove (112) is provided inside the bottom plate (109), and two sides of the disc-type base (108) are connected to the positioning groove (112) by screws.

8. A hydraulic system for an extruder according to claim 7, characterized in that: A magnetic ring (111) is provided on the outer wall of the disc-type base (108), and a magnetic repulsion ring (113) is provided on the inner wall of the positioning groove (112).

9. A hydraulic system for an extruder according to claim 8, characterized in that: A support frame (110) is installed on the outside of the base plate (109), and the permanent magnet synchronous servo motor (101) is connected to the coupling (103) via a flange. A connecting piece (114) is installed at the connection between the support frame (110) and the flange, and the connecting piece (114) is connected to the side of the flange via bolts.

10. A method for using a hydraulic system for an extruder, implemented based on the hydraulic system for an extruder according to claim 9, characterized in that: The following steps are involved: Step 1: The extruder PLC controller (3) sends a flow command to the servo driver (2) based on the preset speed N1; Step 2: After receiving the flow command, the servo driver (2) feeds back a signal to the servo controller (102). At this time, when the oil pressure is not established and there is still space in the pipeline, the servo controller (102) controls the permanent magnet synchronous servo motor (101) to operate according to the preset flow command, and operates the oil pump in a manner proportional to the flow rate and speed; Step 3: After the pipeline is flushed with oil, the oil body is restricted by the pipeline to establish oil pressure, and the pressure sensor (107) at the outlet end of the oil pump (104) detects the oil pressure in real time and feeds back the data to the servo driver (2); Step 4: After receiving the oil pressure information, the servo driver (2) calculates the appropriate servo motor speed N2 based on the difference between the pressure command and the pressure feedback based on the PID algorithm, and feeds back the signal to the servo controller (102) to control the speed of the permanent magnet synchronous servo motor (101) to N2, so that the oil pressure of the oil pump (104) is stabilized at a given value.

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