Electric servo regulating valve and control method thereof

Abstract

The invention relates to an electric servo regulating valve and a control method thereof, and belongs to the technical field of fluid control. Comprising a servo motor, a precise planetary reducer, an electric cylinder, a valve frame and an adjusting valve body which are sequentially connected. An absolute encoder is arranged in the servo motor; a ball screw transmission part is integrated in the electric cylinder, the adjusting valve body comprises a valve rod, a valve cover and a valve body, the ball screw transmission part is connected with the precise planetary reducer and the valve rod, and the precise planetary reducer drives the valve rod to do linear motion through a ball screw when rotating, so that the opening degree of the valve is controlled. The servo control driver is used for driving a servo motor and is electrically connected with the main control PLC and the absolute encoder respectively, and the rotation of the servo motor is controlled through the detected motor position and motor speed. The problems that a traditional electric control valve is low in action speed, large in system inertia, low in control precision and the like are solved.

Description

Technical Field

[0001] This invention belongs to the field of fluid control technology and relates to an electric servo regulating valve and its control method. Background Technology

[0002] Fluid control, as a crucial component of numerous production processes, places stringent demands on the performance of control equipment. High speed, high precision, and high reliability have become important indicators for evaluating the quality of fluid control equipment. However, traditional electric control valves have revealed many insurmountable technical problems in practical applications, making them unable to adequately meet these comprehensive needs of modern industry.

[0003] Traditional electric control valves primarily rely on ordinary motors, such as stepper motors and AC asynchronous motors. These motors require a series of reduction transmission mechanisms, including gears and lead screws, to drive the valve core. This design inherently introduces numerous hidden problems, resulting in significant performance shortcomings.

[0004] Because ordinary motors have inherent inertia, they cannot respond instantaneously during startup and shutdown, requiring a certain amount of time to accelerate and decelerate. Furthermore, to obtain sufficient driving force to move the valve core, the transmission mechanism often employs a large reduction ratio. This makes the valve core's movement extremely slow, with the entire actuation time frequently measured in seconds. In production scenarios requiring extremely high response speeds, such as rapid proportioning adjustments in chemical production or precise fluid transport on automated production lines, this slow movement speed makes "high-speed" control impossible, severely impacting production efficiency and product quality.

[0005] Furthermore, the high system inertia of traditional electric control valves is also a significant problem. When faced with frequently changing command signals, the large inertia of the motor and transmission mechanism makes it difficult for the valve core to quickly follow the commands and adjust accordingly. Under frequent acceleration, deceleration, and steering commands, it cannot react flexibly and quickly. This lag causes fluid control to fail to reach the set value in a timely and accurate manner, thus affecting the stability and reliability of the entire production process.

[0006] Furthermore, the backlash and friction issues in the transmission chain cannot be ignored. Gears and leadscrews inevitably develop backlash after prolonged operation. These backlashes cause "free travel" in the valve core during movement, creating a significant control dead zone. That is, when the command signal changes within a certain range, the valve core will not respond accordingly; it will only begin to move when the signal change exceeds a certain amplitude and overcomes the backlash. Simultaneously, friction between transmission components introduces nonlinear factors, causing the valve core's movement to not strictly follow the linear change of the command signal, but rather exhibit irregular fluctuations. This undoubtedly severely affects control accuracy and makes it difficult to meet the high-precision fluid control requirements of modern industry.

[0007] In summary, traditional electric control valves suffer from numerous problems in terms of high-speed response, rapid command tracking, and control accuracy, making them inadequate when facing the comprehensive requirements of high speed, high precision, and high reliability for fluid control in modern industry. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide an electric servo regulating valve and its control method, which solves the problems of slow action speed, large system inertia and low control accuracy of traditional electric regulating valves.

[0009] To achieve the above objectives, the present invention provides the following technical solution: An electric servo regulating valve includes a servo motor, a precision planetary reducer, an electric cylinder, a valve frame, and a regulating valve body connected in sequence. The servo motor has a built-in absolute encoder for measuring the servo motor's rotation angle and speed. The electric cylinder integrates a ball screw drive component. The regulating valve body includes a valve stem. The ball screw drive component is connected to the precision planetary reducer and the valve stem. When the precision planetary reducer rotates, it drives the valve stem to move linearly via the ball screw, thereby controlling the valve opening.

[0010] Optionally, the regulating valve body further includes a valve cover and a valve body connected in sequence, the valve stem passing through the center of the valve cover and extending into the valve body, and the valve stem being coaxial with the valve cover.

[0011] Optionally, the valve cover is fixed to the valve body by bolts and nuts, forming a sealed cavity inside to accommodate the valve stem and valve core.

[0012] Optionally, the valve core includes a cage-type guide tube and a valve seat connected to each other, the valve stem passes through the central hole of the cage-type guide tube, and the valve stem and the cage-type guide tube are guided to allow the valve stem to move along its axial direction; the cage-type guide tube and the valve seat are fixedly connected by a press-fit method.

[0013] Optionally, the electric cylinder also stores lubricating oil to reduce friction between parts.

[0014] Optionally, the electric cylinder also integrates a valve position limit switch signal output plug for connecting to the valve position limit switch, facilitating the detection of the valve stem position.

[0015] Optionally, the servo motor is equipped with an absolute encoder signal plug and a power supply plug, which facilitates the connection of the absolute encoder and the power supply.

[0016] Optionally, it also includes a servo control driver that drives the servo motor. The servo control driver is electrically connected to the main control PLC and the absolute encoder respectively, so as to control the rotation of the servo motor by detecting the motor position and motor speed.

[0017] A control method for an electric servo regulating valve, employing any of the above-mentioned electric servo regulating valves, wherein the electric servo regulating valve includes a servo control driver that drives the servo motor, the servo control driver being electrically connected to a main control PLC and an absolute encoder respectively, so as to control the rotation of the servo motor by detecting the motor position and motor speed; The control method includes the following steps: S1, Core Control: The main control PLC calculates the required valve opening based on the target flow rate and pressure, and sends control commands to the servo control driver. S2, Power Execution: The servo control driver converts the received commands into current and voltage to drive the servo motor to rotate; S3, Mechanical Action: The rotational motion of the servo motor is transmitted to the regulating valve body through a precision planetary reducer and ball screw transmission components, causing the valve stem to move, thereby changing the valve opening and regulating the flow and pressure of the medium in the pipeline; S4, Position / Speed ​​Detection: The absolute encoder detects the position and speed of the motor in real time; S5, Feedback signal: The encoder returns the value measured in S4 as a feedback signal to the servo control driver; S6, Closed-loop regulation: The servo control driver compares the received feedback signal with the command signal received from the main control PLC; if there is a deviation, the servo control driver will immediately adjust the current output to the motor to correct the error and ensure the accuracy of the valve opening.

[0018] Optionally, step S0, setting and instruction, is also included: the operator or the superior system sets the target flow rate and pressure through the main control PLC.

[0019] The beneficial effects of this invention are as follows: This invention utilizes a servo motor to drive a high-density planetary reducer. The planetary reducer's rotation, via a ball screw drive within an electric cylinder, propels the valve stem in a linear motion, thereby controlling the valve opening. This invention achieves high-speed, high-precision dynamic regulation of flow and pressure, and can be paired with various valve bodies to adapt to different hydraulic systems under various operating conditions. Furthermore, this invention employs advanced PROFINET bus control combined with a main PLC for servo control, forming a closed-loop control system. This results in faster response, higher precision, and multi-axis collaborative control. It meets the stringent requirements of modern industry for high-speed, high-precision, and high-dynamic performance in fluid control processes.

[0020] This invention, by employing a high-speed servo motor, low-inertia transmission components, and an optimized mechanical structure, enables the valve to respond rapidly to control commands, achieving high-speed dynamic regulation of fluid flow and pressure. It solves the problem of slow operation in traditional valves due to high motor inertia and high reduction ratios in the transmission chain.

[0021] The absolute encoder built into the servo motor of this invention provides high-resolution, interference-resistant position and speed feedback. Combined with the closed-loop control system formed by the servo driver, it reduces the absolute error of valve stem displacement. Through closed-loop control, the measurement and control accuracy is improved, achieving precise positioning and real-time correction of the valve stem position. This greatly eliminates the control dead zone and nonlinearity caused by backlash and friction in traditional transmissions, thus achieving extremely high adjustment accuracy and repeatability.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a high-speed electric servo control valve. Figure 2 This is a schematic diagram of the regulating valve body structure; Figure 3 This is a schematic diagram of the valve core structure; Figure 4 This is a flowchart of the control process for a high-speed electric servo regulating valve.

[0024] Figure label: 1 Servo motor, 2 Precision planetary reducer, 3 Electric cylinder, 4 Valve frame, 5 Regulating valve body, 6 Absolute encoder signal plug, 7 Power supply plug, 8 Valve position limit switch signal output plug, 11 Valve stem, 12 Valve cover, 13 Bolt, 14 Nut, 15 Valve body, 22 Cage guide tube, 23 Valve seat. Detailed Implementation

[0025] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0027] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0028] Example 1 Please see Figures 1-3 This refers to an electric servo control valve, specifically an electric servo control valve used in industrial automation, aerospace, precision testing equipment and other fields, for high-speed and high-precision dynamic regulation of the flow and pressure of liquid media.

[0029] The electric servo control valve includes a servo motor 1, a precision planetary reducer 2, an electric cylinder 3, a high-rigidity valve frame 4, and a control valve body 5 connected in sequence. The high-rigidity valve frame 4 is installed at the end of the electric cylinder 3, connecting the control valve body 5 and providing support and fixation. The servo motor 1 has a built-in absolute encoder, which measures the rotation angle and speed of the servo motor 1. The electric cylinder 3 integrates a ball screw drive component and stores lubricating oil inside to reduce friction between components. The control valve body 5 includes a valve cover 12 and a valve body 15 connected in sequence. The valve stem 11 passes through the center of the valve cover 12 and extends into the valve body 15, coaxial with the valve cover 12. The ball screw drive component is connected to the precision planetary reducer 2 and the valve stem 11. When the precision planetary reducer 2 rotates, it drives the valve stem 11 to move linearly via the ball screw, thereby controlling the valve opening. The absolute encoder has advantages such as high-precision positioning and strong anti-interference ability. The precision planetary reducer 2 has advantages such as compact structure, high precision, and high load capacity.

[0030] Furthermore, sealing packing is provided between the valve cover 12 and the valve stem 11, and between the valve body 15, respectively. The valve stem 11 and the valve cover 12 achieve a dynamic seal through the packing structure to prevent media leakage. In some embodiments of the present invention, the sealing packing structure can use V-type packing or flexible graphite packing, capable of withstanding temperatures from -60°C to 500°C. The valve cover 12 is fixed to the valve body 15 by bolts 13 and nuts 14, forming a sealed cavity inside to accommodate the valve stem 11 and valve core. Bolts 13 and nuts 14 tighten the valve cover 12 and the valve body 15, ensuring that the valve remains sealed and operates safely under pressure.

[0031] Furthermore, the valve core includes an interconnected cage-type guide cylinder 22 and a valve seat 23. The valve stem 11 passes through the central hole of the cage-type guide cylinder 22, and the valve stem 11 and the cage-type guide cylinder 22 are guided together to allow the valve stem 11 to move axially. The cage-type guide cylinder 22 and the valve seat 23 are fixedly connected by a press-fit method, serving to guide and support the valve stem 11. As the basic component of the valve core, the valve seat 23 supports and positions the cage-type guide cylinder 22 and the valve stem 11, ensuring the sealing performance and control accuracy of the media flow.

[0032] Furthermore, the electric cylinder 3 also integrates a valve position limit switch signal output plug 8, which is used to connect the valve position limit switch to facilitate the detection of the highest and lowest positions of the valve stem 11, thereby ensuring the safety of the electric cylinder 3.

[0033] Furthermore, the servo motor 1 is equipped with an absolute encoder signal plug 6 and a power supply plug 7, which facilitates the connection of the absolute encoder and the power supply.

[0034] The high-speed electric servo regulating valve of the present invention also includes a servo control driver for driving the servo motor 1. The servo control driver is electrically connected to the main control PLC and the absolute encoder respectively, so as to control the rotation of the servo motor 1 by detecting the motor position and motor speed.

[0035] Example 2 Based on Embodiment 1 above, this embodiment further specifies that the servo motor 1 can be selected with a 220V or 380V power supply, its power can reach 1800W, its speed can reach a maximum of 6000RPM, and it can also meet the increased safety explosion-proof requirements. The output shaft thrust of the electric cylinder 3 can reach a maximum of 15000N, its shaft speed can reach 250mm / s, and its switching time is 80ms; the nominal diameter range of the valve body 15 is DN15~DN150, and its nominal pressure rating range is PN16~PN320. The end face connection of the valve body 15 is rich, and RF raised face flange, FM concave-convex face flange, and RJ ring sealing flange can be selected. Its material is silica sol precision casting valve body or forging valve body. The valve stem 11 is made of SUS630 material, which has the characteristics of high strength and strong corrosion resistance.

[0036] A control method for an electric servo regulating valve, employing the electric servo regulating valve in any of the above embodiments, includes the following steps: S0, Setting and Instruction: Operators or higher-level systems set target flow and pressure through the main control PLC.

[0037] S1, Core Control: The main control PLC calculates the valve opening required for regulating valve body 5 based on the target flow rate and pressure, and sends control commands to the servo control driver. S2, Power Execution: The servo control driver converts the received commands into current and voltage, driving servo motor 1 to rotate; S3, Mechanical Action: The rotational motion of the servo motor 1 is transmitted to the regulating valve body 5 through the precision planetary reducer 2 and ball screw transmission components, causing the valve stem 11 to move, thereby changing the valve opening and regulating the flow and pressure of the medium in the pipeline; S4, Position / Speed ​​Detection: The absolute encoder detects the position and speed of the motor in real time; S5, Feedback signal: The encoder returns the value measured in S4 as a feedback signal to the servo control driver; S6, Closed-loop regulation: The servo control driver compares the received feedback signal with the command signal received from the main control PLC; if there is a deviation, the servo control driver will immediately adjust the current output to the motor to correct the error and ensure the accuracy of the valve opening.

[0038] This invention uses a servo motor 1 to drive a high-density planetary reducer. The planetary reducer's rotation, via a ball screw drive within an electric cylinder 3, causes the valve stem 11 to move linearly, thereby controlling the valve opening. This invention achieves high-speed, high-precision dynamic regulation of flow and pressure, and can be paired with different specifications of regulating valve bodies 5 to adapt to hydraulic systems under various operating conditions. This invention employs advanced PROFINET bus control combined with a main control PLC for servo control, forming a closed-loop control system. This results in faster response, higher precision, and multi-axis collaborative control. It meets the stringent requirements of modern industry for high-speed, high-precision, and high-dynamic performance in fluid control processes.

[0039] This invention, by employing a high-speed servo motor, low-inertia transmission components, and an optimized mechanical structure, enables the valve to respond rapidly to control commands, achieving high-speed dynamic regulation of fluid flow and pressure. It solves the problem of slow operation in traditional valves due to the large inertia of the motor and the high reduction ratio of the transmission chain.

[0040] The absolute encoder built into the servo motor 1 of this invention provides high-resolution, interference-resistant position and speed feedback. Combined with the closed-loop control system formed by the servo driver, the absolute displacement error of the valve stem 11 can reach up to ±0.005mm, comparable to the displacement accuracy of CNC machine tools. Through closed-loop control, the adjustment and control accuracy is less than 0.1%, which is 5 to 10 times higher than that of the electric actuator (analog measurement and control), achieving precise positioning and real-time correction of the valve stem 11. This greatly eliminates the control dead zone and nonlinearity caused by backlash and friction in traditional transmission, thus achieving extremely high adjustment accuracy and repeatability.

[0041] The valve stem 11 of the present invention has a maximum displacement speed of 250 mm / s, an average displacement adjustment speed of 40 to 100 mm / s, and a maximum stroke of less than 120 mm. This enables rapid adjustment of the position of the valve stem 11 to regulate the valve opening, thereby rapidly regulating the flow rate and pressure of the fluid.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An electrically powered servo-controlled valve characterized by: Including the servo motor (1) connected in turn, precision planetary reducer (2), electric cylinder (3), valve holder (4) and regulating valve body (5);The servo motor (1) is built-in absolute encoder, and the absolute encoder is used for measuring the rotation angle and rotation speed of the servo motor (1);The electric cylinder (3) is integrated with ball screw drive component, the regulating valve body (5) includes valve stem (11), the ball screw drive component is connected with precision planetary reducer (2), valve stem (11) respectively, the precision planetary reducer (2) rotates and drives valve stem (11) to move linearly through ball screw, to control the size of valve opening.

2. The electrically powered servo-controlled valve of claim 1, wherein: The regulating valve body (5) further includes valve cover (12) and valve body (15) connected in turn, the valve stem (11) passes through the center of valve cover (12) and extends into the valve body (15), and the valve stem (11) is coaxial with the valve cover (12).

3. The electrically powered servo-controlled valve of claim 2, wherein: The valve cover (12) is fixed on the valve body (15) by bolts (13) and nuts (14), and forms a sealed cavity inside, for accommodating the valve stem (11) and valve core.

4. The electrically powered servo-controlled valve of claim 3, wherein: The valve core includes cage guide sleeve (22) and valve seat (23) connected with each other, the valve stem (11) passes through the center hole of the cage guide sleeve (22), and the valve stem (11) is guided and matched with the cage guide sleeve (22), so that the valve stem (11) can move along its axial direction;The cage guide sleeve (22) and valve seat (23) are fixedly connected by press-fitting.

5. The electrically powered servo-controlled valve of claim 1, wherein: The electric cylinder (3) also stores lubricating oil inside, to reduce the friction between parts.

6. The electrically powered servo modulating valve of claim 1, wherein: The electric cylinder (3) is also integrated with valve position limit switch signal output plug (8) for connecting valve position limit switch, to facilitate detection of the position of valve stem (11).

7. The electrically powered servo-controlled valve of claim 1, wherein: The servo motor (1) is provided with absolute encoder signal plug (6) and power supply plug (7), to facilitate connection of absolute encoder and power supply.

8. The electrically powered servo modulating valve of claim 1 wherein: It also includes a servo control driver for driving the servo motor (1), and the servo control driver is electrically connected with the main control PLC and the absolute encoder respectively, to control the rotation of the servo motor (1) through the detected motor position and motor speed. 9.A control method of an electric servo regulating valve, characterized in that: The electric servo regulating valve according to any one of claims 1-8 is used, wherein the electric servo regulating valve includes a servo control driver for driving the servo motor (1), and the servo control driver is electrically connected with the main control PLC and the absolute encoder respectively, to control the rotation of the servo motor (1) through the detected motor position and motor speed; The control method includes the following steps: S1, core control: the main control PLC calculates the valve opening degree required by the regulating valve body (5) according to the target flow and pressure, and sends a control instruction to the servo control driver; S2, power execution: the servo control driver converts the received instruction into current and voltage to drive the servo motor (1) to rotate. S3, mechanical action: the rotary motion of servo motor (1) is transmitted to the regulating valve body (5) through precision planetary reducer (2) and ball screw transmission components, so that the valve stem (11) moves, thereby changing the valve opening, adjusting the medium flow and pressure in the pipeline; S4, position / speed detection: absolute encoder detects the position and speed of the motor in real time; S5, feedback signal: the encoder returns the measured value in S4 to the servo control driver as a feedback signal; S6, closed-loop regulation: the servo control driver compares the received feedback signal with the instruction signal received from the master PLC; if there is a deviation, the servo control driver will immediately adjust the current output to the motor to correct the error and ensure the accuracy of the valve opening.

10. The control method of the electrically driven servo regulating valve according to claim 9, characterized by: It also includes step S0, setting and instruction: the operator or the superior system sets the target flow and pressure through the master PLC.

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