Pressure control system and laminator

Abstract

The application relates to a pressure control system and a laminating machine. The laminating machine comprises a pressing device and a pressure control system. The pressure control system comprises a plunger cylinder, a hydraulic oil tank, a servo valve and a controller. The plunger cylinder provides a pressing pressure of the pressing device when the hydraulic oil flows in the plunger cylinder. The hydraulic oil flows out of the plunger cylinder and is stored in the hydraulic oil tank. When a difference between the pressing pressure and a preset target pressure value is within a preset first pressure difference range, the hydraulic oil in the plunger cylinder flows back to the hydraulic oil tank through the servo valve. The controller is configured to generate a control pressure of the servo valve based on the pressing pressure and a preset target pressure threshold value when a difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, so as to adjust the hydraulic oil flow rate flowing back to the hydraulic oil tank from the servo valve, and make the difference between the pressing pressure and the preset target pressure value be within a preset second pressure difference range. The pressure control system can accurately control the pressing pressure of the pressing device, and the laminating machine can be accurately processed.

Description

Technical Field

[0001] This application relates to the field of PCB (Printed Circuit Board) manufacturing technology, and in particular to a pressure control system and a laminator. Background Technology

[0002] When processing PCBs, it is usually necessary to use a laminating device to press the PCBs together. Therefore, accurately controlling the pressure applied by the laminating device to the PCB is a particularly important part of the processing.

[0003] In existing technologies, the pressure applied to PCBs by laminating equipment can be controlled using solenoid valve technology. The main function of the solenoid valve in the process is to control the flow of fluids (such as gas or liquid), thereby achieving automated control of the laminating pressure. In other words, by designing a pressure control system incorporating solenoid valves, the flow of fluid is controlled, and thus the laminating pressure is controlled by the fluid flow.

[0004] However, current pressure control systems have issues with accuracy in controlling the bonding pressure, thus failing to accurately bond the PCB. Summary of the Invention

[0005] Therefore, it is necessary to provide a pressure control system that accurately controls the lamination pressure and a laminator that accurately laminates PCBs, in order to address the above-mentioned technical problems.

[0006] In a first aspect, this application provides a pressure control system, comprising:

[0007] A plunger cylinder, in which hydraulic oil flows, is configured to provide the pressing pressure of the pressing device;

[0008] The oil tank is configured to store the hydraulic oil flowing out of the piston cylinder;

[0009] The servo valve is located between the piston cylinder and the oil tank. When the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, the servo valve is in the open state, so that the hydraulic oil in the piston cylinder flows back to the oil tank.

[0010] The controller is configured as follows:

[0011] If the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, the control pressure of the servo valve is generated based on the pressing pressure and the preset target pressure threshold.

[0012] Based on the control pressure, the flow rate of hydraulic oil returning from the servo valve to the oil tank is adjusted so that the difference between the pressing pressure and the preset target pressure value is within the preset second pressure difference range.

[0013] In one embodiment, the controller is further configured to:

[0014] Based on the pressing pressure and the preset target pressure threshold, pressure difference information is generated, and the cumulative error information of the pressure control system is detected.

[0015] The control pressure of the servo valve is generated based on the pressure difference information and the cumulative error information.

[0016] In one embodiment, the cumulative error information includes cumulative differential error information and cumulative integral error information, and the controller is further configured to:

[0017] The pressure difference information, cumulative differential error information, and cumulative integral error information are weighted and processed to generate the control pressure of the servo valve;

[0018] Specifically, when the difference between the pressing pressure and the preset target pressure value is within the preset third pressure difference range, the weight of the cumulative differential error information is increased and the weight of the cumulative integral error information is decreased, and the preset third pressure difference range belongs to the preset first pressure difference range.

[0019] In one embodiment, the controller is further configured to:

[0020] Obtain the rated pressure difference information and rated hydraulic oil flow control information of the servo valve;

[0021] Based on the control pressure, pressing pressure, rated pressure difference information and rated hydraulic oil flow control information, hydraulic oil flow control information is generated. The hydraulic oil flow control information is used to adjust the flow rate of hydraulic oil flowing back to the oil tank from the servo valve.

[0022] In one embodiment, the system further includes:

[0023] The first pressure pump is connected to the plunger cylinder. When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range and the preset fifth pressure difference range, the first pressure pump is configured to supply the plunger cylinder with the first hydraulic oil, wherein the pressure of the first hydraulic oil is greater than the preset hydraulic oil pressure threshold.

[0024] The second pressure pump is connected to the piston cylinder. When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the second pressure pump is configured to supply the piston cylinder with second hydraulic oil, wherein the pressure of the second hydraulic oil is less than the preset hydraulic oil pressure threshold.

[0025] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the plunger cylinder receives the first hydraulic oil and the second hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0026] When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the plunger cylinder receives the first hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range.

[0027] In one embodiment, the system further includes:

[0028] The low-pressure unloading valve is located between the second pressure pump and the oil tank. When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the low-pressure unloading valve is in the open state. The low-pressure unloading valve is configured to unload the second pressure pump and cause the plunger cylinder to flow the second hydraulic oil back to the oil tank.

[0029] A three-position four-way directional valve is located between the first pressure pump and the oil tank. When the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range, the three-position four-way directional valve is in the open state. The three-position four-way directional valve is configured to unload the first pressure pump and cause the plunger cylinder to flow the first hydraulic oil back to the oil tank.

[0030] In one embodiment, the system further includes:

[0031] A first control valve is located between the first pressure pump and the piston cylinder. The first control valve is configured to control the first pressure pump to provide first hydraulic oil to the piston cylinder in one direction.

[0032] The second control valve is located between the second pressure pump and the piston cylinder. The second control valve is configured to control the second pressure pump to provide second hydraulic oil to the piston cylinder in one direction.

[0033] In one embodiment, the system further includes:

[0034] A pressure sensor is installed in the piston cylinder. The pressure sensor is configured to detect the pressing pressure provided by the piston cylinder to the pressing device and send the detected pressing pressure to the controller.

[0035] In one embodiment, the system further includes:

[0036] When the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range, the accumulator group is connected to the plunger cylinder. The accumulator group is configured to supply the plunger cylinder with first hydraulic oil, wherein the pressure of the first hydraulic oil is greater than the preset hydraulic oil pressure threshold.

[0037] In one embodiment, the system further includes:

[0038] The return oil cooler is connected to the oil tank and is configured to cool the hydraulic oil flowing back to the oil tank.

[0039] The aforementioned pressure control system includes: a plunger cylinder configured to provide pressing pressure for the pressing device when hydraulic oil flows into it; an oil tank configured to store hydraulic oil flowing out of the plunger cylinder; and a servo valve located between the plunger cylinder and the oil tank. When the difference between the detected pressing pressure and a preset target pressure value is within a preset first pressure difference range, the servo valve is open, allowing the hydraulic oil in the plunger cylinder to flow back to the oil tank. At this time, because the pressure control system is an inertial system, overshoot is easily caused, meaning the pressing pressure exceeds the preset target pressure value by a certain range. Therefore... A servo valve can be used instead of a solenoid valve, and an additional controller can be set up to continuously control the flow of hydraulic oil returning from the servo valve to the oil tank in real time. Since the servo valve is more sensitive than the solenoid valve, and the controller generates the control pressure of the servo valve in real time by comparing the pressing pressure with the preset target pressure threshold, it can accurately adjust the flow of hydraulic oil returning from the servo valve to the oil tank. In turn, the hydraulic oil flow in the oil tank can be used to accurately control the pressing pressure, so that the difference between the pressing pressure and the preset target pressure value is within the preset second pressure difference range. Therefore, the pressure control method of the pressing equipment by combining the servo valve and the controller is more accurate.

[0040] Secondly, this application provides a laminator, including a laminating device and the aforementioned pressure control system; wherein, the laminating device is provided with multi-layer laminating plates, the PCB to be laminated is disposed between the multi-layer laminating plates, the laminating device is used to laminate the PCB, and the pressure control system is used to control the laminating pressure of the laminating device.

[0041] The aforementioned laminator includes a pressing device and a pressure control system. Since the pressure control system can accurately control the pressing pressure of the pressing device, when the PCB to be pressed is processed by pressing a multi-layer pressing plate in the laminator, the pressure control system can be used to accurately control the pressing pressure of the pressing device to achieve accurate pressing of the PCB by the pressing device. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a structural block diagram of the pressure control system in one embodiment;

[0044] Figure 2 This is a block diagram of the pressure control system in another embodiment;

[0045] Figure 3 This is a structural block diagram of the pressure control system in yet another embodiment;

[0046] Figure 4 This is a structural block diagram of the pressing machine in one embodiment;

[0047] Figure 5 This is a block diagram of the overall structure of the pressing machine in a specific application embodiment;

[0048] Figure 6 This is a schematic diagram of the closed-loop control logic in the pressure process control of one embodiment. Detailed Implementation

[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0051] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0052] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0053] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0054] When used herein, the singular forms of “a,” “an,” and “ / the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0055] In the PCB (Printed Circuit Board) manufacturing process, lamination equipment is usually used to press the PCB together. Therefore, accurately controlling the pressure applied by the lamination equipment to the PCB is a crucial part of the manufacturing process.

[0056] In existing technologies, the pressure applied to PCBs by laminating equipment can be controlled using solenoid valve technology. The main function of the solenoid valve in the process is to control the flow of fluids (such as gas or liquid), thereby achieving automated control of the laminating pressure. In other words, by designing a pressure control system incorporating solenoid valves, the flow of fluid is controlled, and thus the laminating pressure is controlled by the fluid flow.

[0057] However, current pressure control systems often suffer from problems such as insufficient dynamic response and significant pressure overshoot (>2%FS), leading to poor system stability. Pressure overshoot refers to the phenomenon where, when the hydraulic system pressure reaches the set value, the actual pressure exceeds this set value by a certain range due to various factors, before gradually returning to a stable state. Furthermore, during multi-stage pressure switching, the accumulator leakage compensation is insufficient, resulting in excessive pressure fluctuations during the pressure holding phase. Moreover, after long-term operation, the control accuracy of traditional solenoid valves decreases due to valve core wear or electromagnet temperature rise.

[0058] Therefore, this application provides a pressure control system, including: a plunger cylinder configured to provide pressing pressure for a pressing device when hydraulic oil flows into the plunger cylinder; an oil tank configured to store hydraulic oil flowing out of the plunger cylinder; and a servo valve disposed between the plunger cylinder and the oil tank. When the difference between the detected pressing pressure and a preset target pressure value is within a preset first pressure difference range, the servo valve is in an open state, causing the hydraulic oil in the plunger cylinder to flow back to the oil tank. At this time, since the pressure control system is an inertial system, overshoot is likely to occur, that is, the pressing pressure exceeds the preset target pressure value by a certain range. Therefore, a servo valve can be used instead of a solenoid valve, and an additional controller can be set up to continuously control the flow of hydraulic oil returning from the servo valve to the oil tank in real time. Since the servo valve is more sensitive than the solenoid valve, and the controller generates the control pressure of the servo valve in real time by using the pressing pressure and the preset target pressure threshold, it can accurately adjust the flow of hydraulic oil returning from the servo valve to the oil tank. In turn, the hydraulic oil flow in the oil tank can be used to accurately control the pressing pressure, so that the difference between the pressing pressure and the preset target pressure value is within the preset second pressure difference range. Therefore, the pressure control method of the pressing equipment by combining the servo valve and the controller is more accurate.

[0059] Based on the aforementioned pressure control system, a laminator is also provided. The laminator includes a pressing device and a pressure control system. Therefore, when the PCB to be pressed is processed by pressing a multi-layer pressing plate in the laminator, the pressure control system can be used to accurately control the pressing pressure of the pressing device to achieve accurate pressing of the PCB by the pressing device.

[0060] like Figure 1 As shown, this application provides a pressure control system 10. The system includes:

[0061] When hydraulic oil flows into the plunger cylinder 100, the plunger cylinder 100 is configured to provide the pressing pressure of the pressing device 200;

[0062] Oil tank 400 is configured to store hydraulic oil flowing out of piston cylinder 100;

[0063] The servo valve 300 is located between the piston cylinder 100 and the oil tank 400. When the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, the servo valve is in the open state, so that the hydraulic oil in the piston cylinder 100 flows back to the oil tank 400.

[0064] The controller 500 is configured to: generate a control pressure for the servo valve 300 based on the pressure and the preset target pressure threshold when the difference between the detected pressing pressure and the preset target pressure value is within a preset first pressure difference range; and adjust the flow rate of hydraulic oil flowing back from the servo valve 300 to the oil tank 400 according to the control pressure until the difference between the pressing pressure and the preset target pressure value is within a preset second pressure difference range.

[0065] Among them, the plunger cylinder 100 is a hydraulic or pneumatic actuator. Its core structure consists of a plunger (piston rod) and a cylinder. Unlike traditional piston cylinders, the plunger of the plunger cylinder 100 only makes linear reciprocating motion within the cylinder and does not form a sealing fit with the inner wall of the cylinder. When hydraulic oil or compressed air enters one end of the plunger cylinder 100, the plunger produces linear motion under pressure. The plunger cylinder 100 provides pressing pressure to the pressing device 200 through the linear motion generated by the plunger.

[0066] The pressing equipment 200 can be a hot press connected to the plunger cylinder 100. The pressing equipment is not part of the pressure control system 10; the pressure control system 10 provides the pressing pressure for PCB pressing. Specifically, the pressing equipment 200 uses the pressing pressure provided by the plunger cylinder 100 to press the PCB. The pressing equipment 200 has a multi-layer pressing structure, and the pressing method can be to place the PCB into the multi-layer pressing structure for pressing.

[0067] The servo valve 300 is an actuator in a servo system that converts an electrical signal input into a high-power flow signal output. It can accurately convert weak electrical signals into high-power hydraulic signals. When an electrical signal is input, the electromagnetic component generates electromagnetic force, driving the valve core of the servo valve 300 to move, changing the flow area of ​​the hydraulic valve port, thereby controlling the flow rate of hydraulic oil. Furthermore, the servo valve 300 of this application is designed with a shock-absorbing component, i.e., a valve sleeve covering the valve core of the servo valve 300, to reduce the impact of shock vibration, extend the life of the servo valve 300, and ensure that the leakage of the servo valve 300 is <0.05 L / min. The servo valve 300 in this application is generally a piezoelectric servo valve 300, possessing micron-level displacement resolution (0.1μm), fast response capability (≤5ms), and pressure regulation accuracy of ±0.3% FS. It uses a stacked actuator to achieve precise control of the valve core displacement and supports dynamic response above 0Hz.

[0068] The oil tank 400 is a container used to store liquids, typically made of metal (such as steel or aluminum) or plastic, and its core function is to store, supply, and cool the stored liquids. In this application, the oil tank 400 is used to store hydraulic oil.

[0069] The controller 500 in this application can dynamically adjust the control quantity according to the deviation between the set value (target value) and the actual output value, so that the system can quickly and accurately track the target value. In practical applications, the controller 500 is generally a PID (Proportional-Integral-Derivative) controller, which is a closed-loop control device that adjusts the error through three links: proportional (P), integral (I), and derivative (D).

[0070] Specifically, the pressure control system 10 mainly includes four parts: piston cylinder 100, oil tank 400, servo valve 300 and controller 500.

[0071] First, hydraulic oil is introduced into the plunger cylinder 100 to control the plunger in the plunger cylinder 100 to make linear motion, thereby providing pressing pressure to the pressing equipment 200 so that the pressing equipment 200 can accurately press the PCB.

[0072] At this time, in order to control the pressing pressure provided by the plunger cylinder 100, a servo valve 300 can be set between the plunger cylinder 100 and the oil tank 400. The plunger cylinder 100 and the oil tank 400 are connected through the servo valve 300. When the servo valve 300 is in the open state, the hydraulic oil in the plunger cylinder 100 flows back to the oil tank 400 through the servo valve 300. When the servo valve 300 is in the closed state, the hydraulic oil in the plunger cylinder 100 cannot flow back to the oil tank 400 through the servo valve 300 and continues to be stored in the plunger cylinder 100.

[0073] Furthermore, the servo valve 300 can control the flow rate of hydraulic oil from the servo valve 300 back to the oil tank 400 by controlling the opening of its own hydraulic valve port. On this basis, in order to more accurately control the pressing pressure provided by the piston cylinder 100, a controller 500 can be set up. The controller 500 can have a direct or indirect communication connection with the servo valve. For example, the controller 500 can be directly connected to the servo valve through a communication line, or it can be connected to the drive component first, and then communicate with the servo valve through the drive component.

[0074] The controller 500 generates the control pressure of the servo valve 300 based on the existing pressing pressure, and then adjusts the flow rate of hydraulic oil flowing back from the servo valve 300 to the oil tank 400 based on the control pressure, and then uses the hydraulic oil flow rate to provide feedback control of the existing pressing pressure.

[0075] In detail, the controller 500 first detects the pressing pressure of the plunger cylinder 100 to the pressing device 200, which can be achieved by setting a pressure sensor. Next, the controller 500 determines whether the pressing pressure needs to be controlled. When the detected pressing pressure is close to the preset target pressure value, that is, when the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range, since this system is an inertial control system, due to inertia, the pressing pressure may overshoot by a certain range beyond the preset target pressure value. Therefore, the servo valve can be opened to allow the hydraulic oil in the plunger cylinder to flow back to the oil tank. The controller 500 also needs to output a certain control pressure to the servo valve 300 according to a pre-set feedback adjustment logic, thereby performing closed-loop regulation of the pressing pressure by adjusting the flow rate of the hydraulic oil flowing back to the oil tank, ensuring that the pressing pressure does not overshoot.

[0076] During the closed-loop regulation process of the controller 500 according to the preset feedback regulation logic, the controller 500 first generates the control pressure of the servo valve 300 based on the pressing pressure and the preset target pressure threshold. Then, based on the control pressure, it generates a hydraulic oil flow control signal. The hydraulic oil flow control signal is used to regulate the flow of hydraulic oil from the servo valve 300 back to the oil tank 400. Therefore, the controller 500 regulates the flow of hydraulic oil from the servo valve 300 back to the oil tank 400 according to the hydraulic oil flow control signal. When the servo valve 300 returns the hydraulic oil to the oil tank 400 according to the hydraulic oil flow control signal, the hydraulic oil in the plunger cylinder 100 gradually decreases, and the pressing pressure of the plunger cylinder 100 on the pressing device 200 also gradually changes. Therefore, the difference between the pressing pressure and the preset target pressure value can be kept within the preset second pressure difference range through the above means. In practical applications, the preset first pressure difference range can be ±0.3% FS, and the second pressure difference range can be ±0.5% FS, where FS stands for "Full". The abbreviation for "Scale" means full scale, which is the maximum value of the scale or the maximum display range. In this application, it can be a preset target pressure value.

[0077] The pressure control system 10 described above includes: a plunger cylinder configured to provide pressing pressure for the pressing device when hydraulic oil flows into it; an oil tank configured to store hydraulic oil flowing out of the plunger cylinder; and a servo valve located between the plunger cylinder and the oil tank. When the difference between the detected pressing pressure and a preset target pressure value is within a preset first pressure difference range, the servo valve is open, allowing the hydraulic oil in the plunger cylinder to flow back to the oil tank. At this time, because the pressure control system 10 is an inertial system, overshoot is easily caused, meaning the pressing pressure exceeds the preset target pressure value by a certain range. Therefore, a servo valve can be used instead of a solenoid valve, and an additional controller can be set up to continuously control the flow of hydraulic oil returning from the servo valve to the oil tank in real time. Since the servo valve is more sensitive than the solenoid valve, and the controller generates the control pressure of the servo valve in real time by using the pressing pressure and the preset target pressure threshold, it can accurately adjust the flow of hydraulic oil returning from the servo valve to the oil tank. In turn, the hydraulic oil flow in the oil tank can be used to accurately control the pressing pressure, so that the difference between the pressing pressure and the preset target pressure value is within the preset second pressure difference range. Therefore, the pressure control method of the pressing equipment by combining the servo valve and the controller is more accurate.

[0078] In one exemplary embodiment, the controller 500 is further configured to:

[0079] Based on the pressing pressure and the preset target pressure threshold, pressure difference information is generated, and the cumulative error information of the pressure control system 10 is detected; based on the pressure difference information and the cumulative error information, the control pressure of the servo valve 300 is generated.

[0080] Specifically, when the difference between the detected pressing pressure and the preset target pressure value is within a preset first pressure difference range, the controller 500 obtains pressure difference information based on the pressing pressure and the preset target pressure threshold. Further, the pressure difference information is actually the difference between the pressing pressure and the preset target pressure threshold. Let the pressing pressure be ps and the preset target pressure threshold be p0, then the pressure difference information is p0-ps.

[0081] The controller 500 is a controller that adjusts the error. Therefore, the controller 500 not only needs to detect the pressure difference information between the pressing pressure and the preset target pressure threshold, but also needs to detect the cumulative error information of the pressure control system 10, so as to combine the pressure difference information and the cumulative error information to generate the control pressure of the servo valve 300.

[0082] Furthermore, based on the pressure difference information and the cumulative error information, the control pressure of the servo valve 300 is generated. This can be achieved by weighting and summing the pressure difference information and the cumulative error information. The weighting coefficient can be gradually adjusted based on the characteristics of the controller 500 itself, historical experience, and system feedback.

[0083] In the above embodiments, based on the pressing pressure and the preset target pressure threshold, the pressure difference information can be accurately obtained. Then, by weighted summing the cumulative error information and the pressure difference information of the pressure control system 10, the control pressure of the servo valve 300 can be accurately generated.

[0084] In an exemplary embodiment, the cumulative error information includes cumulative differential error information and cumulative integral error information, and the controller 500 is further configured to:

[0085] The pressure difference information, cumulative differential error information, and cumulative integral error information are weighted and processed to generate the control pressure of the servo valve 300.

[0086] In this application, the controller 500 is generally a PID controller used to perform proportional-integral-derivative processing on the input data. When the difference between the pressing pressure and the preset target pressure value is within a preset third pressure difference range, the weight of the cumulative derivative error information is increased, and the weight of the cumulative integral error information is decreased. The preset third pressure difference range falls within a preset first pressure difference range.

[0087] Specifically, the cumulative error information generally includes cumulative differential error information and cumulative integral error information. Both the cumulative differential error information and the cumulative integral error information are derived from the cumulative error of the pressure control system 10. The cumulative error of the pressure control system 10 includes, but is not limited to, sensor pressure detection error and sampling time error.

[0088] When the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, pressure difference information is generated based on the pressing pressure and the preset target pressure threshold. The cumulative differential error information and cumulative integral error information of the pressure control system 10 are detected. Based on the pressure difference information, the cumulative differential error information and the cumulative integral error information, the control pressure of the servo valve 300 is generated.

[0089] Furthermore, based on the pressure difference information, cumulative differential error information, and cumulative integral error information, the control pressure of the servo valve 300 is generated. This includes weighting the pressure difference information, cumulative differential error information, and cumulative integral error information to generate the control pressure of the servo valve 300. More specifically, the proportional coefficient corresponding to the pressure difference information, the differential coefficient corresponding to the cumulative differential error information, and the integral coefficient corresponding to the cumulative integral error information are obtained. Based on the proportional coefficient corresponding to the pressure difference information, the pressure difference information is updated; based on the differential coefficient, the cumulative differential error information is updated; and based on the integral coefficient, the cumulative integral error information is updated. The control pressure of the servo valve 300 is then generated based on the updated pressure difference information, cumulative differential error information, and cumulative integral error information. The proportional coefficient corresponding to the pressure difference information, the differential coefficient corresponding to the cumulative differential error information, and the integral coefficient corresponding to the cumulative integral error information are three constants, which are gradually adjusted based on historical experience and system feedback.

[0090] For example, let the pressure difference information be ep, the cumulative differential error information be derivative, the cumulative integral error information be integral, the proportional coefficient corresponding to the pressure difference information be kp, the differential coefficient corresponding to the cumulative differential error information be derivative, and the integral coefficient corresponding to the cumulative integral error information be integral, then the expression for the control pressure u of the generated servo valve 300 is: .

[0091] However, during the generation of control pressure for the servo valve 300, errors accumulate continuously due to the integral action. Even when the error is close to zero, over-adjustment may still occur due to the cumulative effect. When the difference between the pressurized pressure and the preset target pressure value is within the preset third pressure difference range—that is, when the detected pressurized pressure is very close to the preset target pressure value and the entire pressure control system 10 is in the pressure stabilization phase—the main objective of the system is to maintain pressure stability, rather than quickly eliminating errors. At this time, the role of the integral term may become secondary, or even lead to excessive control quantity due to accumulated errors. Therefore, to avoid pressure overshoot, the weight of the accumulated differential error information can be increased, while the weight of the accumulated integral error information can be decreased. That is, a derivative-dominated approach can be adopted to keep the control pressure of the servo valve 300 stable. Here, the preset third pressure difference range falls within the preset first pressure difference range. In this derivative-dominated control strategy, proportional control still plays a fundamental role. The proportional control directly adjusts the control quantity based on the current pressure difference information to ensure a rapid system response.

[0092] Furthermore, in the process of increasing the weight of cumulative differential error information and decreasing the weight of pressure difference information and cumulative integral error information, one method is to avoid pressure overshoot by shielding the integral term, thus keeping the control pressure of the servo valve 300 stable. Further methods for avoiding pressure overshoot by shielding the integral term include: 1. Direct zeroing: setting the coefficient Ki of the integral term to zero, or clearing the cumulative integral error information of the integral term to zero; 2. Conditional shielding: shielding the integral term when the pressure difference information is less than a certain threshold; re-enabling the integral term when the error is large.

[0093] In the above embodiments, when the difference between the pressing pressure and the preset target pressure value is within the preset third pressure difference range, the weight of the cumulative differential error information is increased and the weight of the cumulative integral error information is decreased, so that the control pressure of the servo valve 300 is kept stable by using the differential-dominated method, pressure overshoot can be avoided, the control pressure of the servo valve 300 is accurately generated, and the hydraulic oil flow from the servo valve 300 to the oil tank 400 is accurately adjusted.

[0094] In an exemplary embodiment, the controller 500 is further configured to: acquire rated pressure difference information and rated hydraulic oil flow control information of the servo valve 300; and generate hydraulic oil flow control information based on the control pressure, pressure engagement pressure, rated pressure difference information and rated hydraulic oil flow control information.

[0095] The hydraulic oil flow control information is used to regulate the flow rate of hydraulic oil returning from the servo valve 300 to the oil tank 400.

[0096] Specifically, after detecting the control pressure of the servo valve 300, the rated pressure difference information and rated hydraulic oil flow control information of the servo valve 300 are acquired. Then, the control pressure, pressure engagement pressure, rated pressure difference information and rated hydraulic oil flow control information are combined to generate hydraulic oil flow control information, so as to adjust the hydraulic oil flow rate from the servo valve 300 back to the oil tank 400 through the hydraulic oil flow control information.

[0097] Let the control pressure be u, the pressing pressure be ps, the rated pressure difference information be pn, and the rated hydraulic oil flow control information be Q0, then the expression for generating the hydraulic oil flow control information is: At this time, the flow rate of hydraulic oil returning from the servo valve 300 to the oil tank 400 is Q.

[0098] In this embodiment, since the control pressure is generated by the pressing pressure and the preset target pressure value, by combining the control pressure, pressing pressure, rated pressure difference information and rated hydraulic oil flow control information, the hydraulic oil flow control information can be accurately generated, thereby accurately adjusting the hydraulic oil flow from the servo valve 300 back to the oil tank 400.

[0099] In one exemplary embodiment, such as Figure 2 As shown, the system also includes:

[0100] The first pressure pump 600 is connected to the plunger cylinder 100. When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range and the preset fifth pressure difference range, the first pressure pump 600 is configured to supply the first hydraulic oil to the plunger cylinder 100.

[0101] The second pressure pump 700 is connected to the piston cylinder 100. When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the second pressure pump 700 is configured to supply the piston cylinder 100 with second hydraulic oil.

[0102] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the plunger cylinder 100 receives the second hydraulic oil and the first hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0103] When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the plunger cylinder 100 receives the first hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range.

[0104] Both the first pressure pump 600 and the second pressure pump 700 are fixed displacement pumps. The first pressure pump 600 generates higher-pressure first hydraulic oil for applications requiring high-pressure fluid transport, while the second pressure pump 700 generates lower-pressure second hydraulic oil suitable for general fluid transport. The pressure borne by the first hydraulic oil is greater than a preset hydraulic oil pressure threshold, and the pressure borne by the second hydraulic oil is less than the preset hydraulic oil pressure threshold. The preset first pressure difference range, the preset fourth pressure difference range, and the preset fifth pressure difference range are three non-overlapping pressure difference ranges. Any pressure difference within the preset fifth pressure difference range is greater than any pressure difference within the preset fourth pressure difference range, and any pressure difference within the preset fourth pressure difference range is greater than any pressure difference within the preset first pressure difference range.

[0105] Specifically, this application provides two fixed displacement pumps, a first pressure pump 600 and a second pressure pump 700. Both the first pressure pump 600 and the second pressure pump 700 are connected to the plunger cylinder 100. The first pressure pump 600 can provide the plunger cylinder 100 with high-pressure, low-flow first hydraulic oil, and the second pressure pump 700 can provide the plunger cylinder 100 with low-pressure, high-flow second hydraulic oil.

[0106] It should be noted that the first pressure pump 600 and the second pressure pump 700 do not continuously supply hydraulic oil to the plunger cylinder 100. Instead, they supply hydraulic oil to the plunger cylinder 100 only when the pressure reaches a certain level. At this time, pressure difference ranges are sequentially set for the pressure control system 10, including the first pressure difference range, the fourth pressure difference range, and the fifth pressure difference range. Specifically:

[0107] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the pressing pressure is far from the preset target pressure value, requiring a rapid increase in pressing pressure. Therefore, a first pressure pump 600 and a second pressure pump 700 are set up. The second pressure pump 700 provides second hydraulic oil to the plunger cylinder 100, and the first pressure pump 600 provides first hydraulic oil to the plunger cylinder 100. At this time, the plunger cylinder 100 receives the second and first hydraulic oils, and the plunger in the plunger cylinder 100 can move linearly quickly. For example, if the pressing device 200 is above the plunger cylinder 100, the plunger can rise rapidly to provide a gradually increasing pressing pressure to the pressing device 200 until the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0108] When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the gap between the pressing pressure and the preset target pressure value is reduced. At this time, the pressure can be increased slowly. At this time, the second pressure pump 700 does not work, and the first pressure pump 600 continues to work to provide the first hydraulic oil to the plunger cylinder 100. The plunger cylinder 100 receives the first hydraulic oil, and the linear motion speed of the plunger in the plunger cylinder 100 slows down. The pressure increase rate of the pressing pressure provided by the plunger cylinder 100 to the pressing device 200 also slows down until the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range.

[0109] When the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range, since the pressing pressure is already close to the preset target pressure value, the hydraulic oil flow from the plunger cylinder 100 to the oil tank 400 can be adjusted by the controller 500, so that the pressing pressure does not overshoot.

[0110] In this embodiment, by comparing the difference between the pressing pressure and the preset target pressure value with the results of each pressure difference range, it can be determined whether to supply hydraulic oil to the plunger cylinder 100 through the second pressure pump 700 or by combining the second pressure pump 700 and the first pressure pump 600, so as to accurately provide pressing pressure to the pressing device 200.

[0111] In one exemplary embodiment, such as Figure 3 As shown, the system also includes:

[0112] The low-pressure unloading valve 800 is located between the second pressure pump 700 and the oil tank 400. When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the low-pressure unloading valve is in the open state. The low-pressure unloading valve 800 is configured to unload the second pressure pump 700 and cause the plunger cylinder 100 to flow the second hydraulic oil back to the oil tank 400.

[0113] A three-position four-way directional valve 900 is located between the first pressure pump 700 and the oil tank 400. When the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range, the three-position four-way directional valve 900 is in the open state. The three-position four-way directional valve 900 is configured to unload the first pressure pump 600 and cause the piston cylinder 100 to return the first hydraulic oil to the oil tank 400 through the three-position four-way directional valve 900.

[0114] Among them, the low-pressure unloading valve 800 is a valve that can unload the hydraulic pump under certain conditions. When the system is in an unloaded state, the hydraulic oil returns directly to the oil tank 400. The three-position four-way directional valve 900 has three working positions and four oil ports (usually two inlets and two outlets), which are represented by P, T, A, and B respectively. P is the oil inlet, T is the oil return port, and A and B are connected to the upper and lower chambers of the actuator, respectively. The valve's natural position is usually in the neutral position. By changing the position of the valve core, the connection state of the oil circuit is changed, thereby controlling the direction of movement of the actuator.

[0115] Specifically, the pressure control system 10 is further equipped with a low-pressure unloading valve 800 and a three-position four-way directional valve 900. The low-pressure unloading valve 800 is located between the second pressure pump 700 and the oil tank 400, and the three-position four-way directional valve 900 is located between the first pressure pump 600 and the oil tank 400. When the low-pressure unloading valve 800 is in the left position, it is assumed that the passage between the plunger cylinder 100 and the oil tank 400 is open, and the plunger cylinder 100 flows the second hydraulic oil back to the oil tank 400 through the low-pressure unloading valve 800. When the low-pressure unloading valve 800 is in the right position, it is assumed that the passage between the plunger cylinder 100 and the oil tank 400 is closed, and the plunger cylinder 100 cannot flow the second hydraulic oil back to the oil tank 400 through the low-pressure unloading valve 800. When the three-position four-way directional valve 900 is in the left position, it is assumed that the passage between the first pressure pump 600 and the oil tank 400 is open, and the piston cylinder 100 cannot flow the first hydraulic oil back to the oil tank 400 through the three-position four-way directional valve 900; when the three-position four-way directional valve 900 is in the right position, it is assumed that the passage between the first pressure pump 600 and the oil tank 400 is closed, and the piston cylinder 100 can flow the first hydraulic oil back to the oil tank 400 through the three-position four-way directional valve 900.

[0116] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, both the second pressure pump 700 and the first pressure pump 600 operate. The plunger cylinder 100 receives the second hydraulic oil and the first hydraulic oil. At this time, the low-pressure unloading valve 800 is in the right position and the three-position four-way directional valve 900 is in the left position. Both the low-pressure unloading valve 800 and the three-position four-way directional valve 900 are in the closed state, so that the second hydraulic oil and the first hydraulic oil flowing into the plunger cylinder 100 cannot flow back to the oil tank 400 through the low-pressure unloading valve 800 or the three-position four-way directional valve 900. At the same time, the servo valve 300 is in the right position and is also in the closed state, so the hydraulic oil in the plunger cylinder 100 cannot flow back to the oil tank 400 through the plunger cylinder 100. This causes the pressing pressure of the pressing device 200 to increase rapidly until the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0117] When the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range, the three-position four-way directional valve 900 is activated in the left position and is closed. The first pressure pump 600 continues to work, the low-pressure unloading valve 800 is activated in the left position and is opened to unload the second pressure pump 700, and the servo valve 300 is activated in the right position and is closed. At this time, the plunger cylinder 100 receives the first hydraulic oil and the plunger cylinder 100 returns the second hydraulic oil to the oil tank 400 through the low-pressure unloading valve 800. The plunger cylinder 100 cannot return the hydraulic oil to the oil tank 400 through the servo valve 300, which slows down the pressure increase rate of the pressing device 200 until the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range.

[0118] When the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range, the three-position four-way directional valve 900 operates in the right position to unload the first pressure pump 600, the low-pressure unloading valve 800 operates in the left position, the second pressure pump 700 continues to not work, and the servo valve 300 operates in the left position. At this time, both the low-pressure unloading valve 800 and the three-position four-way directional valve 900 are in the open state, and the piston cylinder 100 does not receive the first hydraulic oil from the first pressure pump 600 and the second pressure pump 700. When the first pressure pump 600 is unloaded, the piston cylinder 100 can return the first hydraulic oil to the oil tank 400 through the three-position four-way directional valve 900. At this time, the piston cylinder 100 mainly returns the hydraulic oil to the oil tank 400 through the servo valve 300.

[0119] It should be noted that when the second pressure pump 700 is unloaded, the plunger cylinder 100 does not return all the second hydraulic oil to the oil tank 400. Similarly, when the first pressure pump 600 is unloaded, the plunger cylinder 100 does not return all the first hydraulic oil to the oil tank 400. When the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range, a portion of the hydraulic oil remaining in the plunger cylinder 100 can flow back to the oil tank 400 through the servo valve 300.

[0120] In the above embodiments, by setting a low-pressure unloading valve 800 and a three-position four-way directional valve 900, and by distributively controlling the opening state of the low-pressure unloading valve 800 and the three-position four-way directional valve 900, the piston cylinder 100 is controlled to control whether the hydraulic oil flows back to the oil tank 400, so as to accurately control the pressing pressure at this time.

[0121] In one exemplary embodiment, the system further includes:

[0122] A first control valve is disposed between the first pressure pump 600 and the plunger cylinder 100, and the first control valve is configured to control the first pressure pump 600 to provide first hydraulic oil to the plunger cylinder 100 in one direction; a second control valve is disposed between the second pressure pump 700 and the plunger cylinder 100, and the second control valve is configured to control the second pressure pump 700 to provide second hydraulic oil to the plunger cylinder 100 in one direction.

[0123] Specifically, a first control valve is installed between the first pressure pump 600 and the plunger cylinder 100, and a second control valve is installed between the second pressure pump 700 and the plunger cylinder 100. In this configuration, the first control valve allows the first pressure pump 600 to supply first hydraulic oil to the plunger cylinder 100, but does not allow the first hydraulic oil in the plunger cylinder 100 to flow back to the first pressure pump 600. Similarly, the second control valve allows the second pressure pump 700 to supply second hydraulic oil to the plunger cylinder 100, but does not allow the second hydraulic oil in the plunger cylinder 100 to flow back to the second pressure pump 700. In practical applications, the control valve is a one-way automatic valve. Its core function is to allow fluid (liquid or gas) to flow freely in one direction and completely block it in the opposite direction. It achieves this function through internal mechanical structures (such as valve discs, valve balls, etc.) without external control.

[0124] When hydraulic oil flows from the pump to the piston cylinder 100, the fluid pressure pushes the valve disc (or valve ball) away from the valve seat, forming a passage, and the fluid passes smoothly; when the hydraulic oil attempts to flow back from the piston cylinder 100 to the pump, the valve disc (or valve ball) is pressed against the valve seat by the reverse pressure, preventing the fluid from passing through and forming a seal.

[0125] In this embodiment, the pressure control system 10, by setting a first control valve and a second control valve, enables the second pressure pump 700 to provide second hydraulic oil to the piston cylinder 100 in one direction, and the first pressure pump 600 to provide first hydraulic oil to the piston cylinder 100 in one direction, thus avoiding the backflow of hydraulic oil.

[0126] In one exemplary embodiment, the system further includes a pressure sensor disposed in the plunger cylinder 100, the pressure sensor being configured to detect the pressing pressure provided by the plunger cylinder 100 to the pressing device 200, and to send the detected pressing pressure to the controller 500.

[0127] Among them, a pressure sensor is a sensor that converts pressure signals into electrical signals. When selecting a pressure sensor, attention should be paid to its range, accuracy, sensitivity and response time.

[0128] Specifically, the pressure sensor is installed at the oil inlet of the plunger cylinder 100. When the pressure sensor is in the open state, it detects the pressing pressure provided by the plunger cylinder 100 to the pressing device 200 and sends the detected pressing pressure to the PID controller 500. In practical applications, the pressure sensor can be set as a switch. When the pressure switch is open, the pressure sensor can detect the pressing pressure provided by the plunger cylinder 100 to the pressing device 200; when the pressure switch is closed, the pressure sensor does not need to detect the pressing pressure provided by the plunger cylinder 100 to the pressing device 200.

[0129] In this embodiment, by setting a pressure sensor, the pressing pressure provided by the plunger cylinder 100 to the pressing device 200 can be accurately monitored, so as to assist in the real-time and precise control of the pressing pressure.

[0130] In one exemplary embodiment, the system further includes:

[0131] When the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range, the accumulator group is connected to the plunger cylinder 100, and the accumulator group is configured to provide the plunger cylinder 100 with the first hydraulic oil.

[0132] In this system, the pressure of the first hydraulic oil exceeds a preset hydraulic oil pressure threshold. An accumulator group is a device composed of two or more accumulators combined in a specific manner. It is used in a hydraulic system to store and release energy to meet the system's dynamic demands for pressure, flow, or energy.

[0133] Specifically, when the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, that is, when the pressure control system 10 is in the pressure holding stage, both the first pressure pump 600 and the second pressure pump 700 are unloaded. At this time, the accumulator group is connected to the plunger cylinder 100, and the accumulator group provides the plunger cylinder 100 with the required first hydraulic oil.

[0134] Furthermore, the accumulator group adopts a graded pressure planning, and a stepped pressure curve (such as 0→%→50%→0% FS) is set through a PLC (Programmable Logic Controller), with the pressure boost rate of the accumulator group set independently for each stage.

[0135] Specifically, the energy storage units are divided into different pre-charge pressure levels (such as high pressure, medium pressure, and low pressure), with each level covering a specific pressure range to ensure that the system has sufficient energy reserves under different operating conditions.

[0136] Among them, the high-pressure stage: the pre-charge pressure is close to the preset target pressure value FS of the system, which is used to compensate for instantaneous large flow demand or high-pressure leakage.

[0137] Medium pressure level: The pre-charge pressure is 60% to 80% of the system's preset target pressure value FS, which is used to deal with moderate leakage or flow fluctuations.

[0138] Low-pressure stage: The pre-charge pressure is relatively low and is used to maintain the system base pressure or compensate for minor leaks.

[0139] By combining pressure sensors and control valves, the number of accumulators activated is adjusted in real time according to the pressing pressure. For example, when the pressing pressure drops to the medium-pressure threshold, the system automatically switches to the medium-pressure accumulator group to replenish energy. Accumulator groups are activated sequentially according to the pressure gradient to avoid overcharging and discharging of a single accumulator.

[0140] In one exemplary embodiment, the accumulator group typically consists of multiple accumulator units, connecting pipelines, etc. By combining multiple accumulator units, the accumulator group achieves a larger capacity of energy storage, improving the energy utilization efficiency and stability of the system; the connecting pipelines are used to communicate with the plunger cylinder 100 to provide the plunger cylinder 100 with the required first hydraulic oil.

[0141] In this embodiment, by setting up an accumulator group, the first hydraulic oil can be provided to the plunger cylinder 100 when the pressure control system 10 is in the pressure holding stage, so as to realize the pressure control of the plunger cylinder 100 on the pressing device 200.

[0142] In one exemplary embodiment, the system further includes an oil return cooler connected to the oil tank 400, which is used to cool the hydraulic oil flowing back to the oil tank 400.

[0143] Among them, the return oil cooler is an important cooling device in the hydraulic system, mainly used to reduce the temperature of the system return oil and ensure stable operation of the equipment.

[0144] Specifically, a return oil cooler is connected to the oil tank 400 to cool the hydraulic oil in the tank 400 to below the system's required temperature. Specifically, the return oil cooler can be located near the oil inlet of the oil tank 400 to cool the hydraulic oil before it flows back to the tank 400, ensuring that the hydraulic oil returning to the tank 400 is cooled. Alternatively, the return oil cooler can be located inside the oil tank 400, or outside the tank 400 but connected to its interior, to cool the hydraulic oil inside the tank 400. In practical applications, the hydraulic oil temperature is generally maintained at 40±2℃ to minimize the interference of viscosity changes on flow characteristics.

[0145] Furthermore, oil return coolers typically consist of components such as radiators, fans, oil pumps, pipelines, and control valves. Depending on the cooling medium, they can be divided into air-cooled oil return coolers and water-cooled oil return coolers. Air-cooled oil return coolers use fans to force airflow and remove heat from the hydraulic oil in the radiator; water-cooled oil return coolers utilize cooling water to exchange heat with the hydraulic oil and are suitable for scenarios with high cooling requirements.

[0146] In other words, the return oil cooler uses an oil pump to introduce high-temperature return oil into the radiator, where the oil temperature is reduced by air or water cooling. The cooled hydraulic oil is then circulated back to the oil tank 400. Its core principle is to utilize the temperature difference between the two fluids to achieve heat exchange, thereby cooling the hydraulic oil in the oil tank 400 to below the system's required temperature.

[0147] In this embodiment, by setting up a return oil cooler, the hydraulic oil flowing back to the oil tank 400 can be effectively cooled, avoiding the reduction of hydraulic oil viscosity and the increase of leakage caused by high temperature. It can also reduce the oxidation rate of hydraulic oil and increase the service life of hydraulic oil.

[0148] In an exemplary embodiment, the pressure control system 10 is further provided with a displacement sensor, which is installed at the bottom of the piston cylinder 100 to monitor the movement displacement of the piston inside the piston cylinder 100. The controller 500 acquires the movement displacement of the piston inside the piston cylinder 100 to monitor the movement state of the piston cylinder 100, and monitors the movement speed of the piston cylinder 100 based on the movement displacement of the piston inside the piston cylinder 100 and its corresponding movement time.

[0149] In this embodiment, the pressure of the pressure control system 10 can be indirectly determined by monitoring the movement speed of the piston cylinder 100. For example, when the piston cylinder 100 moves rapidly, it indicates that the piston cylinder 100 receives the second hydraulic oil and the first hydraulic oil, and the pressure control system 10 is in the stage of rapid pressure rise. At this time, the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range. On the other hand, when the movement speed of the piston cylinder 100 slows down, it indicates that the piston cylinder 100 does not receive the second hydraulic oil. At this time, the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0150] This application also provides a laminator, such as Figure 4 As shown, it includes a pressing device 200 and a pressure control system 10 in the above embodiment; wherein, the pressing device 200 is provided with multi-layer pressing plates, the PCB to be pressed is disposed between the multi-layer pressing plates, the pressing device 200 is used to press the PCB, and the pressure control system 10 is used to control the pressing pressure of the pressing device 200.

[0151] Specifically, the laminating equipment 200 is equipped with multiple laminating plates, and the PCB to be laminated is placed between these multiple laminating plates. That is, the PCB to be laminated is placed between the Mth laminating plate and the (M+1)th laminating plate, where M is a positive integer. For example, the PCB to be laminated can be placed between the first and second laminating plates, or between the third and fourth laminating plates. The laminating equipment 200 is used to laminate PCBs, and the laminating equipment 200 can be a hot press or similar device.

[0152] The pressure control system 10 controls the movement of the plunger cylinder 100 by controlling the flow rate in the internal plunger cylinder, thereby controlling the pressing pressure of the pressing device 200 when pressing the PCB, and accurately processing the PCB. Furthermore, during the process of controlling the movement of the plunger cylinder 100 by controlling the flow rate in the internal plunger cylinder 100, the controller 500 can adjust the flow rate of hydraulic oil returning to the oil tank 400 from the plunger cylinder 100 through the servo valve 300, as well as the flow rate of hydraulic oil supplied to the plunger cylinder 100 by the first pressure pump 600 and the second pressure pump 700. Further, the composition and detailed working principle of the pressure control system 10 are as described in the above embodiments, and will not be repeated here.

[0153] The aforementioned laminator includes a laminating device 200 and a pressure control system 10. Since the pressure control system 10 can accurately control the laminating pressure of the laminating device 200, when the PCB to be laminated is processed by laminating a multi-layer laminating plate in the laminator, the pressure control system 10 can be used to accurately control the laminating pressure of the laminating device 200 to achieve accurate processing of the PCB by the laminating device 200.

[0154] In one exemplary embodiment, such as Figure 5 As shown, the laminator provided in this application includes a pressure control system 10 and a hot press 200; wherein, the pressure control system 10 includes: a plunger cylinder 100, a servo valve 300, an oil tank 400, a PID controller 500, a first pressure pump 600, a second pressure pump 700, a low-pressure unloading valve 800, a three-position four-way directional valve 900, a low-pressure overflow valve 1000, a high-pressure overflow valve 1100, a first control valve 1200, a second control valve 1300, a pressure switch 1400, a displacement sensor 1500, an oil return cooler 1600, and an accumulator group 1700. The pressure control system 10 controls the pressing pressure of the hot press 200 to press the PCB. The working principle of the entire pressing process is as follows:

[0155] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the second pressure pump 700 provides low-pressure, high-flow hydraulic oil to the piston cylinder 100, and the first pressure pump 600 provides low-flow, high-pressure hydraulic oil to the piston cylinder 100. Because two streams of hydraulic oil are input, the piston in the piston cylinder 100 can rise rapidly. When the piston cylinder 100 rises rapidly, the low-pressure unloading valve 800 moves to the right position, the three-position four-way directional valve 900 moves to the left position, and the servo valve 300 moves to the right position. This prevents the low-pressure hydraulic oil in the piston cylinder 100 from flowing to the oil tank 400 through the low-pressure unloading valve 800, the high-pressure hydraulic oil in the piston cylinder 100 from flowing to the oil tank 400 through the three-position four-way directional valve 900, and the hydraulic oil in the piston cylinder 100 from flowing to the oil tank 400 through the servo valve 300. At this time, the pressing pressure provided by the plunger cylinder 100 to the hot press 200 also rises rapidly until the difference between the pressing pressure and the preset target pressure value is within the preset fourth pressure difference range.

[0156] When the difference between the pressing pressure and the preset target pressure value is within the preset fifth pressure difference range, the low-pressure unloading valve 800 is activated in the left position, the second pressure pump 700 is unloaded, and the low-pressure hydraulic oil in the piston cylinder 100 flows back to the oil tank 400 through the low-pressure unloading valve 800. The three-position four-way directional valve 900 is activated in the left position, and the high-pressure hydraulic oil in the piston cylinder 100 cannot flow to the oil tank 400 through the three-position four-way directional valve 900. The servo valve 300 is activated in the right position, and the high-pressure hydraulic oil in the piston cylinder 100 cannot flow to the oil tank 400 through the servo valve 300. Therefore, the piston cylinder 100 receives high-pressure hydraulic oil, the rising speed of the piston cylinder 100 slows down, and the pressure increase speed of the pressing pressure provided to the hot press 200 also slows down, until the difference between the pressing pressure and the preset target pressure value is within the preset first pressure difference range.

[0157] When the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, the accumulator group 1700 pipeline is connected to the plunger cylinder 100 to provide the plunger cylinder 100 with the required high-pressure hydraulic oil. At this time, the PID controller 500 outputs a certain control voltage u to the servo valve 300 according to the preset feedback adjustment logic, so as to perform closed-loop PID adjustment of the pressing pressure of the pressure control system by adjusting the flow rate.

[0158] The PID controller 500 is connected to the servo valve 300. Its closed-loop PID control process actually constructs a closed loop of "pressure setpoint → PID controller 500 output → servo valve 300 drive → sensor feedback," correcting pressure deviations in real time. Figure 6 As shown, the closed-loop control logic in pressure process control specifically includes:

[0159] Taking a 3-position 4-way H-type servo valve 300 as an example, the servo valve 300 dynamically adjusts the system's engagement pressure by regulating the flow rate. The hydraulic oil flow rate returning to the oil tank 400 from the B and T ports of the servo valve 300 is... Q0 is the rated hydraulic oil flow rate of servo valve 300, ps is the engagement pressure, pn is the rated pressure difference, and u is the control pressure of servo valve 300. ep = p0 - ps, where p0 is the preset target pressure value, ep is the pressure difference between the pressing pressure and the preset target pressure value, kp, Ki, and Kd are the coefficients of each term, integral is the cumulative integral error, and derivative is the cumulative differential error.

[0160] Based on the generated hydraulic oil flow rate Q, the hydraulic oil flow rate returning from the servo valve 300 to the oil tank 400 is adjusted so that the difference between the pressing pressure and the preset target pressure value is within the preset second pressure difference range, and does not deviate too far from the preset target pressure value.

[0161] Furthermore, when the difference between the pressing pressure and the preset target pressure value is within the preset third pressure difference range, the PID controller 500 will switch to the derivative-dominated mode, that is, increase the weight of the cumulative derivative error information and decrease the weight of the cumulative integral error information. The preset third pressure difference range belongs to the preset first pressure difference range. For example, the PID controller 500 can shield the integral term in the above expression to avoid pressure overshoot.

[0162] Furthermore, the primary function of the first control valve 1200 and the second control valve 1300 is to prevent hydraulic oil backflow. The pressure switch 1400 is installed near the oil inlet of the piston cylinder 100. The pressure switch 1400 can measure the pressing pressure provided by the piston cylinder 100 to the hot press 200. This pressure value can be collected and recorded by the controller. The displacement sensor 1500 is installed at the bottom of the piston cylinder 100 and can detect the displacement of the piston inside the piston cylinder 100. By collecting the displacement of the piston inside the piston cylinder 100, the controller can detect the movement state of the piston cylinder 100 and calculate its rising speed. The return oil cooler 1600 cools the hydraulic oil returning to the oil tank 400 to below the system's required temperature.

[0163] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0164] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A pressure control system, characterized in that, The system includes: A plunger cylinder, in which hydraulic oil flows, is configured to provide the pressing pressure of the pressing device; An oil tank configured to store hydraulic oil flowing from the plunger cylinder; A servo valve is installed between the plunger cylinder and the oil tank. When the difference between the detected pressing pressure and the preset target pressure value is within the preset first pressure difference range, the servo valve is in the open state, so that the hydraulic oil in the plunger cylinder flows back to the oil tank. The controller is configured to: If the difference between the detected pressing pressure and the preset target pressure value is within a preset first pressure difference range, the control pressure of the servo valve is generated based on the pressing pressure and the preset target pressure threshold. Based on the control pressure, the flow rate of hydraulic oil flowing back from the servo valve to the oil tank is adjusted so that the difference between the pressing pressure and the preset target pressure value is within a preset second pressure difference range.

2. The pressure control system according to claim 1, characterized in that, The controller is also configured to: Based on the pressing pressure and the preset target pressure threshold, pressure difference information is generated, and the cumulative error information of the pressure control system is detected. The control pressure of the servo valve is generated based on the pressure difference information and the cumulative error information.

3. The pressure control system according to claim 2, characterized in that, The cumulative error information includes cumulative differential error information and cumulative integral error information, and the controller is further configured to: The pressure difference information, the cumulative differential error information, and the cumulative integral error information are weighted and processed to generate the control pressure of the servo valve; Wherein, when the difference between the pressing pressure and the preset target pressure value is within a preset third pressure difference range, the weight of the cumulative differential error information is increased and the weight of the cumulative integral error information is decreased, and the preset third pressure difference range belongs to the preset first pressure difference range.

4. The pressure control system according to claim 1, characterized in that, The controller is also configured to: Obtain the rated pressure difference information and rated hydraulic oil flow control information of the servo valve; Hydraulic oil flow control information is generated based on the control pressure, the pressing pressure, the rated pressure difference information, and the rated hydraulic oil flow control information. The hydraulic oil flow control information is used to adjust the flow rate of hydraulic oil flowing back from the servo valve to the oil tank.

5. The pressure control system according to claim 1, characterized in that, The system also includes: A first pressure pump, which is connected to the plunger cylinder, is configured to supply first hydraulic oil to the plunger cylinder when the difference between the pressing pressure and the preset target pressure value is within a preset fourth pressure difference range and a preset fifth pressure difference range. The pressure of the first hydraulic oil is greater than a preset hydraulic oil pressure threshold. The second pressure pump is connected to the plunger cylinder. When the difference between the pressing pressure and the preset target pressure value is within a preset fifth pressure difference range, the second pressure pump is configured to supply the plunger cylinder with second hydraulic oil, wherein the pressure of the second hydraulic oil is less than a preset hydraulic oil pressure threshold. When the difference between the pressing pressure and the preset target pressure value is within a preset fifth pressure difference range, the plunger cylinder receives the first hydraulic oil and the second hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within a preset fourth pressure difference range. When the difference between the pressing pressure and the preset target pressure value is within a preset fourth pressure difference range, the plunger cylinder receives the first hydraulic oil until the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range.

6. The pressure control system according to claim 5, characterized in that, The system also includes: A low-pressure unloading valve is disposed between the second pressure pump and the oil tank. When the difference between the pressing pressure and the preset target pressure value is within a preset fourth pressure difference range, the low-pressure unloading valve is in the open state. The low-pressure unloading valve is configured to unload the second pressure pump and cause the plunger cylinder to flow the second hydraulic oil back to the oil tank. A three-position four-way directional valve is disposed between the first pressure pump and the oil tank. When the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range, the three-position four-way directional valve is in the open state. The three-position four-way directional valve is configured to unload the first pressure pump and cause the plunger cylinder to flow the first hydraulic oil back to the oil tank.

7. The pressure control system according to claim 5, characterized in that, The system also includes: A first control valve is disposed between the first pressure pump and the plunger cylinder, and the first control valve is configured to control the first pressure pump to unidirectionally supply first hydraulic oil to the plunger cylinder; A second control valve is disposed between the second pressure pump and the plunger cylinder. The second control valve is configured to control the second pressure pump to unidirectionally supply second hydraulic oil to the plunger cylinder.

8. The pressure control system according to claim 1, characterized in that, The system also includes: A pressure sensor is disposed in the plunger cylinder, and the pressure sensor is configured to detect the pressing pressure provided by the plunger cylinder to the pressing device, and send the detected pressing pressure to the controller.

9. The pressure control system according to claim 1, characterized in that, The system also includes: When the difference between the pressing pressure and the preset target pressure value is within a preset first pressure difference range, the accumulator group is connected to the plunger cylinder, and the accumulator group is configured to supply the plunger cylinder with first hydraulic oil, wherein the pressure of the first hydraulic oil is greater than a preset hydraulic oil pressure threshold.

10. The pressure control system according to claim 1, characterized in that, The system also includes: An oil return cooler is connected to the oil tank and is configured to cool the hydraulic oil flowing back to the oil tank.

11. A laminator, characterized in that, The invention includes a pressing device and a pressure control system as described in any one of claims 1-10; wherein the pressing device is provided with multiple pressing plates, the PCB to be pressed is disposed between the multiple pressing plates, the pressing device is used to press the PCB to be pressed, and the pressure control system is used to control the pressing pressure of the pressing device.

Images