Servo valve control system based on spool rotation

Abstract

The application provides a kind of including hydraulic valve, first motor, second motor, hydraulic cylinder, first driver and second driver;Valve core body is arranged in hydraulic valve, large valve core is sleeved in the valve core body, small valve core is sleeved in the large valve core, the large valve core is connected with first motor, the small valve core is connected with second motor;First driver drives first motor to run, second driver drives second motor to run, displacement sensor is arranged at the front end of the telescopic shaft of hydraulic cylinder, displacement sensor is electrically connected with second driver, displacement sensor can feedback displacement signal of displacement sensor to second driver to make second driver drive second motor to run.The application is set by using the above control system, so that servo valve control system can not only realize closed-loop control, improve the precision of control, but also can be applied in constant pressure guaranteeing and other profiling movements, and the universality of use is further expanded.

Description

Technical Field

[0001] This invention belongs to the field of servo valve control system design technology, specifically relating to a servo valve control system based on valve core rotation. Background Technology

[0002] In existing technologies, there are generally two methods for controlling hydraulic cylinders: digital cylinders and servo valves. However, extensive practical experience has revealed that both existing technologies have significant drawbacks in controlling the position of hydraulic cylinders.

[0003] First, when using digital cylinders to precisely control the position of hydraulic cylinders, position control relies on the movement of the valve core within the system. This valve core movement depends entirely on the transmission of the lead screw and nut, which inevitably introduces transmission backlash. Furthermore, with prolonged use, the wear of the nut and nut increases, further widening the backlash. Due to this backlash, the hydraulic cylinder's position control will experience significant displacement deviations. Additionally, this transmission method places extremely high demands on the valve core, lead screw, and servo motor, resulting in high manufacturing costs and a short service life.

[0004] Secondly, when using servo valves to control the position of hydraulic cylinders, the viscosity, temperature, density, and purity of the hydraulic fluid have a significant impact on the cylinder's displacement due to the very small valve opening. Therefore, hydraulic control systems using electro-hydraulic servo valves are generally equipped with complex hydraulic power units to ensure high-standard hydraulic fluid operation. Furthermore, because this control requires real-time monitoring of the hydraulic fluid, the hydraulic state involves complex control algorithms for the cylinder's motion. Consequently, servo valves are equipped with dedicated, independent servo control units, resulting in high prices and maintenance costs. If integration into a general-purpose control system is required, customized development of the control system is necessary. Summary of the Invention

[0005] To address the above problems, this invention redesigns a new servo valve control system based on valve core rotation. By adopting the above control system settings, the servo valve control system can not only achieve closed-loop control and improve control accuracy, but also be applicable to contour movements such as ensuring constant pressure, thus further expanding its applicability.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A servo valve control system based on valve core rotation includes a hydraulic valve, a first motor, a second motor, a hydraulic cylinder, a first actuator, and a second actuator.

[0008] A valve core body is provided inside the hydraulic valve, a large valve core is installed inside the valve core body, and a small valve core is installed inside the large valve core. The large valve core is connected to a first motor, and the small valve core is connected to a second motor.

[0009] The hydraulic valve is provided with an oil inlet, an oil return port, a working oil port A, and a working oil port B; the oil inlet, oil return port, working oil port A, and working oil port B are respectively connected to the inner cavity of the valve core body;

[0010] The hydraulic cylinder is provided with cylinder A port and cylinder B port, cylinder A port is connected to working oil port A, and cylinder B port is connected to working oil port B;

[0011] The first driver drives the first motor to operate, and the second driver drives the second motor to operate. A displacement sensor is provided at the front end of the telescopic shaft of the hydraulic cylinder. The displacement sensor is electrically connected to the second driver. The displacement sensor can feed back the displacement signal of the displacement sensor to the second driver, so that the second driver drives the second motor to operate.

[0012] In a preferred embodiment of the present invention, a first axial adjustment sleeve is provided on the side of the large valve core facing the first motor, and a second axial adjustment sleeve is provided on the side of the small valve core facing the second motor. The first axial adjustment sleeve, the large valve core, the small valve core, and the second axial adjustment sleeve are coaxially installed.

[0013] In a preferred embodiment of the present invention, a first coupling is provided on the end face of the large valve core facing the first motor, and the output shaft of the first motor is connected to the large valve core through the first coupling; a sealing sleeve is provided on the side of the small valve core facing the second motor, and the second axial adjustment sleeve is located between the sealing sleeve and the second motor.

[0014] In a preferred embodiment of the present invention, the valve core is a circular hollow structure with openings at both ends. Four parallel first annular grooves a, b, c, and d are formed on the outer surface of the valve core along its axial direction. The first annular grooves a, b, c, and d are respectively connected to the oil inlet, working oil port A, return oil port, and working oil port B on the hydraulic valve. At least one first through hole is formed at the bottom of each of the first annular grooves a, b, c, and d.

[0015] As a preferred embodiment of the present invention, the large valve core is a circular hollow structure with an opening on one side. The outer surface of the large valve core is provided with four parallel second annular grooves m, i, j and k along its axial direction. The second annular grooves m, i, j and k are respectively connected to the first annular grooves a, b, c and d.

[0016] As a preferred embodiment of the present invention, at least one second through hole is provided at the bottom of the second annular groove m; 2n third through holes are uniformly arranged at equal angles at the bottom of the second annular groove i; and 2n fourth through holes are uniformly arranged at equal angles at the bottom of the second annular groove j. The third through holes and the fourth through holes are arranged in the same direction and correspond one-to-one.

[0017] As a preferred embodiment of the present invention, 2n fifth through holes are uniformly arranged at the bottom of the second annular groove k at equal angles, and the 2n fifth through holes are staggered from the fourth through holes by an angle.

[0018] As a preferred embodiment of the present invention, the small valve core is a circular hollow structure with a single-sided opening. 2n sixth through holes and 2n seventh through holes are provided on the outer surface of the small valve core. A third annular groove t is also provided between the sixth through hole and the seventh through hole. The third through hole, the fifth through hole, the sixth through hole and the seventh through hole are all through holes with square structures.

[0019] As a preferred embodiment of the present invention, a first notch groove is provided between every two adjacent sixth through holes, and a second notch groove is provided between every two adjacent seventh through holes. The first notch groove and the second notch groove are directly opposite each other and connected to the third annular groove t. The sixth through hole, the first notch groove, and the second annular groove i correspond to each other, and the seventh through hole, the second notch groove, and the second annular groove k correspond to each other.

[0020] As a preferred embodiment, both the first motor and the second motor are servo motors or stepper motors.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The servo valve control system based on valve core rotation described in this invention, through the above-mentioned control system settings, enables the servo valve control system to not only achieve closed-loop control and improve control accuracy, but also to be applicable in contour movements such as maintaining constant pressure, further expanding its applicability. Compared to digital hydraulic cylinders, it has a shorter intermediate transmission chain and higher control accuracy. Furthermore, this invention has a simple structure and control method, and can be directly connected to any motion controller, achieving high motion accuracy. Compared to proportional servo valves, this invention does not require complex control algorithms or independent control systems, has a simple control method, can be directly connected to any motion controller, and achieves high motion accuracy. It also has low requirements for oil quality and temperature, making it economical and reliable. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0024] Figure 1 This is a schematic diagram of the overall structure of the servo valve control system based on valve core rotation according to the present invention.

[0025] Figure 2 This is a schematic diagram of the overall structure of the hydraulic valve, the first motor, and the second motor of the present invention after installation.

[0026] Figure 3 for Figure 2 Schematic diagram of the internal structure of a medium-pressure hydraulic valve;

[0027] Figure 4 This is a schematic diagram of the internal cross-sectional structure of the hydraulic valve in this invention;

[0028] Figure 5 This is a schematic diagram of the mating structure of the valve core body, the large valve core, and the small valve core in this invention;

[0029] Figure 6 This is a schematic diagram of the front end face of the hydraulic valve in this invention;

[0030] Figure 7 This is a schematic diagram of the rear end face of the hydraulic valve in this invention;

[0031] Figure 8 This is a schematic diagram of the overall structure of the valve core in this invention;

[0032] Figure 9 This is a schematic diagram of the large valve core when n=1 in this invention;

[0033] Figure 10 This is a schematic diagram of the small valve core when n=1 in this invention;

[0034] Figure 11 This is a schematic diagram of the large valve core structure when n=2 in this invention;

[0035] Figure 12 This is a schematic diagram of the small valve core when n=2 in this invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Please see Figures 1 to 3As shown, this embodiment of the invention provides a servo valve control system based on valve core rotation, specifically including a hydraulic valve 10, a first motor 21, a second motor 22, a hydraulic cylinder 30, a first driver 41, and a second driver 42. A valve core body 11 is disposed within the hydraulic valve 10, a large valve core 12 is fitted inside the valve core body 11, and a small valve core 13 is fitted inside the large valve core 12. The large valve core 12 is connected to the first motor 21, and the small valve core 13 is connected to the second motor 22. The hydraulic valve 10 is provided with an oil inlet P, an oil return port T, a working oil port A, and a working oil port B. The oil inlet P, oil return port T, working oil port A, and working oil port B are respectively connected to the inner cavity of the valve core body 11. The hydraulic cylinder 30 is provided with a cylinder A port 31 and a cylinder B port 32. The cylinder A port 31 is connected to the working oil port A, and the cylinder B port 32 is connected to the working oil port B. The first actuator 41 drives the first motor 21 to operate, and the second actuator 42 drives the second motor 22 to operate. A displacement sensor 43 is installed at the front end of the telescopic shaft of the hydraulic cylinder 30. The displacement sensor 43 is electrically connected to the second actuator 42. The displacement sensor 43 can feed back its displacement signal to the second actuator 42, thereby causing the second actuator 42 to drive the second motor 22 to operate. Rotation control is achieved through separate actuators (the first actuator 41 and the second actuator 42), ensuring the independence of the rotation of the large and small valve cores.

[0038] Specifically, in this embodiment, the displacement sensor 43 enables the second motor 22 to rotate in sync with the first motor 21. Specifically, when the first motor 21 starts, opening the oil circuit, the telescopic shaft of the hydraulic cylinder 30 extends. This movement causes the displacement sensor 43 to generate a displacement signal, which is transmitted to the second driver 42. The second driver 42 then drives the second motor 22, causing the small valve core 13 to follow the rotation of the large valve core 12, thus disconnecting the oil circuit. By utilizing the coordination between the displacement sensor 43 and the driver, the follow-up movement between the large and small valve cores 12 is better ensured, guaranteeing continuous circulation of the oil circuit between opening and closing, and greatly improving the movement accuracy of the telescopic shaft.

[0039] Further optimizing this embodiment, the servo valve control system based on valve core rotation also includes a motion controller 44. The displacement sensor 43 is electrically connected to the motion controller 44, which is also electrically connected to the first driver 41. The motion controller 44 transmits control signals to the first driver 41 based on the displacement signal from the displacement sensor 43. When the telescopic shaft moves (either extending or retracting), the displacement sensor 43 located at the head of the telescopic shaft emits a position pulse signal. This pulse signal is divided into two paths: one path connects to the position detection interface of the motion controller 44 to transmit the motion signal of the telescopic shaft to the motion controller 44, controlling the first motor 21 to stop rotating after the telescopic shaft reaches its position; the other path connects to the second driver 42 to control the second motor 22 to maintain its follow-up motion with the first motor 21. Through the design of the above structure, closed-loop control of the telescopic shaft's movement position is ensured, resulting in higher motion accuracy.

[0040] Optionally, a pressure sensor (not shown) can be installed at the front end of the hydraulic cylinder's telescopic shaft. This pressure sensor is electrically connected to the motion controller 44 to provide feedback on the pressure data signal at the front end of the telescopic shaft. This pressure feedback is incorporated into the motion control algorithm, enabling pressure control at the front end of the telescopic shaft. This control method is particularly suitable for contouring motion. Specifically, contouring motion can be understood as follows: a preset pressure range at the front end of the telescopic shaft is established. During the extension or retraction of the telescopic shaft, if the pressure sensor detects that the pressure exerted by the telescopic shaft on an object exceeds the preset pressure range, the pressure sensor transmits this signal to the motion controller 44, causing the telescopic shaft to move appropriately in the opposite direction to reduce the pressure to the preset range, ensuring constant pressure. By adopting the above control system settings, the servo valve control system can not only achieve closed-loop control and improve control accuracy, but also be applicable to contouring motions that ensure constant pressure, further expanding its applicability. This novel design enables the servo valve system provided in this application to have high motion accuracy. At the same time, through reasonable cooperation between internal valve cores, the speed of the piston movement of the hydraulic cylinder 30 can be controlled by changing the speed of the motors (first motor 21 and second motor 22).

[0041] Please see Figure 3 and Figure 4As shown, mounting flanges 33 and connectors 34 are respectively provided on the left and right sides of the hydraulic valve 10. The mounting flanges 33 and connectors 34 facilitate the installation and fixation of the first motor 21 and the second motor 22. Simultaneously, to further improve the installation accuracy of the large valve core 12 and the small valve core 13, a first axial adjustment sleeve 14 is provided on the side of the large valve core 12 facing the first motor 21, and a second axial adjustment sleeve 15 is provided on the side of the small valve core 13 facing the second motor 22. The first axial adjustment sleeve 14, the large valve core 12, the small valve core 13, and the second axial adjustment sleeve 15 are coaxially mounted. The first axial adjustment sleeve 14 is used to adjust the large valve core 12 in the axial direction, and the second axial adjustment sleeve 15 is used to adjust the small valve core 13 in the axial direction, ensuring precise positioning and installation of the large and small valve cores.

[0042] In this embodiment, a sealing sleeve 16 is also provided on the side of the small valve core 13 facing the second motor 22, and a second axial adjusting sleeve 15 is located between the sealing sleeve 16 and the second motor 22. A first coupling 17, which serves as a sealing and connecting element, is provided on the end face of the large valve core 12 facing the first motor 21, and the output shaft of the first motor 21 is connected to the large valve core 12 through the first coupling 17. A second coupling 18, which serves as a sealing and connecting element, is provided on the end face of the small valve core 13 facing the second motor 22, and the output shaft of the second motor 22 is connected to the small valve core 13 through the second coupling 18. Furthermore, to further reduce the motor load, axial bearings can be installed between the large valve core 12, the small valve core 13, and their corresponding adjusting sleeves 14 and sealing sleeves 16 to reduce the friction force during valve core movement, reduce the motor load, improve the motor's dynamic response characteristics, and thus improve the motion accuracy of the hydraulic cylinder.

[0043] In this embodiment, a unique design is made to the structure of the hydraulic valve 10, valve core 11, large valve core 12, and small valve core 13. The large valve core 12 and small valve core 13 are independently controlled by the first motor 21 and the second motor 22, so that the large valve core 12 and small valve core 13 can rotate independently within the valve core body. This completes the continuous connection (i.e., connection), closure (i.e., disconnection), reconnection, and high-speed cycle of the oil circuit, thereby realizing micro-oil supply to the hydraulic cylinder and micro-feed control of the hydraulic cylinder piston. Through this mutual rotation of the valve cores, high-precision control of the hydraulic cylinder movement is achieved.

[0044] Please see Figures 1 to 7As shown, the servo valve control system based on valve core rotation specifically includes a hydraulic valve 10, a first motor 21, and a second motor 22. A valve core body 11 is disposed within the hydraulic valve 10, a large valve core 12 is fitted inside the valve core body 11, and a small valve core 13 is fitted inside the large valve core 12. The large valve core 12 is connected to the first motor 21, and the small valve core 13 is connected to the second motor 22. The hydraulic valve 10 is provided with an oil inlet P, an oil return port T, a working oil port A, and a working oil port B; the oil inlet P, oil return port T, working oil port A, and working oil port B are respectively connected to the inner cavity of the valve core body 11. The valve core body 11 is a circular hollow structure open at both ends. Several first annular grooves are formed along the axial direction on the outer surface of the valve core body 11, and at least one first through hole 100 is formed at the bottom of each first annular groove. The large valve core 12 is a circular hollow structure with an opening on one side. Several second annular grooves are axially formed on the outer surface of the large valve core 12, each of which communicates with a corresponding first annular groove. The small valve core 13 is also a circular hollow structure with an opening on one side. Several sixth through holes 600 and several seventh through holes 700 are provided on the outer surface of the small valve core 13. A third annular groove t is also provided between the sixth and seventh through holes 600 and 700, respectively corresponding to the second annular grooves.

[0045] Please see Figures 1 to 7 As shown, the hydraulic valve 10 and the first motor 21 and the second motor 22 are located on the left and right ends of the hydraulic valve 10. The servo valve movement is achieved through the cooperation of the two motors (i.e., the first motor 21 and the second motor 22) to achieve high-precision control. The two motors are symmetrically arranged on both sides of the hydraulic valve 10. Specifically, the first motor 21 and the second motor 22 can be either servo motors or stepper motors. That is, the servo valve proposed in this application has strong applicability and can be used with different motors. For ease of explanation, this solution uses a servo motor as an example for specific demonstration.

[0046] Please see Figure 5 As shown, the hydraulic valve 10 comprises four parts: the outermost valve body and valve core body 11; the innermost small valve core 13 and the large valve core 12 between the valve core body 11; that is, the valve core body 11 is fitted onto the outer surface of the large valve core 12, and the large valve core 12 is fitted onto the outer surface of the small valve core 13; the valve core body 11, the large valve core 12, and the small valve core 13 are all located inside the valve body. The main innovation in this application lies in the structural design of the valve body, valve core body 11, large valve core 12, and small valve core 13. Through the ingenious arrangement of the structure, the valve core body 11, the large valve core 12, and the small valve core 13 cooperate with each other to achieve the feeding and delivery of hydraulic oil during the rotation of the large valve core 12 and the small valve core 13. The structure of each component is described in detail below:

[0047] Please see Figures 2 to 7As shown, the hydraulic valve 10 has a square structure. An oil inlet P and a return port T are provided on the front end face of the hydraulic valve 10, and a working port A and a working port B are provided on the rear end face. That is, the oil inlet P and the return port T are located on the same side of the end face of the hydraulic valve 10, while the working ports A and B are located on the other side of the end face of the hydraulic valve 10. Of course, the end faces where the oil inlet P, the return port T, the working ports A and B are located can be on different end faces or on the same end face; the specific implementation can be appropriately modified according to the actual situation.

[0048] Please see Figure 8 As shown, the valve core 11 is located inside the hydraulic valve 10. The valve core 11 is a hollow structure with openings on both sides, which can be understood as a cylindrical structure. Four parallel first annular grooves, a, b, c, and d, are formed on the outer surface of the valve core 11 along its axial direction. These first annular grooves a, b, c, and d correspond to and communicate with the oil inlet P, oil return T, working oil port A, and working oil port B on the hydraulic valve 10, respectively. Specifically, the first annular groove a corresponds to and communicates with the oil inlet P, the first annular groove b corresponds to and communicates with the working oil port A, the first annular groove c corresponds to and communicates with the oil return T, and the first annular groove d corresponds to and communicates with the working oil port B. Meanwhile, in order to achieve communication, at least one first through hole 100 is provided at the bottom of the first annular groove a, first annular groove b, first annular groove c and first annular groove d described above. The first through hole 100 is mainly used to achieve communication with the large valve core 12 inside.

[0049] Please see Figure 9As shown, the large valve core 12 is also a hollow structure, but it has a single-sided opening, meaning one side of the large valve core 12 is sealed. The large valve core 12 is housed within the valve core body 11 and is connected to the first motor 21. Specifically, the sealed end of the large valve core 12 is connected to the first motor 21, allowing the large valve core 12 to rotate under the rotation of the first motor 21. Four parallel second annular grooves m, i, j, and k are formed along the axial direction on the outer surface of the large valve core 12. These grooves are respectively connected to the first annular grooves a, b, c, and d. This can be understood as follows: the second annular groove m corresponds to the first annular groove a in position and is connected through the first through hole 100 at the bottom of the first annular groove a; similarly, the second annular groove i corresponds to the first annular groove b in position and is connected through the first through hole 100 at the bottom of the first annular groove b; the second annular groove j corresponds to the first annular groove c in position and is connected through the first through hole 100 at the bottom of the first annular groove c; the second annular groove k corresponds to the first annular groove d in position and is connected through the first through hole 100 at the bottom of the first annular groove d.

[0050] To further optimize this embodiment, at least one second through hole 200 is provided at the bottom of the second annular groove m. It should be noted that the number of first through holes 100 and second through holes 200 can be one, two, three, four, etc. In this embodiment, for the convenience of processing and for structural optimization, four first through holes 100 are provided in the first annular grooves a, b, c, and d respectively, and the four first through holes 100 are arranged in an equal-angled annular array in each first annular groove. Four second through holes 200 are also provided in the second annular groove m, and the four second through holes 200 are arranged in an equal-angled annular array in the second annular groove m.

[0051] To further optimize this embodiment, 2n third through holes 300 are uniformly arranged at equal angles at the bottom of the second annular groove i, and 2n fourth through holes 400 are uniformly arranged at equal angles at the bottom of the second annular groove j. The third through holes 300 and the fourth through holes 400 are arranged in the same direction and correspond one-to-one. 2n fifth through holes 500 are uniformly arranged at equal angles at the bottom of the second annular groove k. The 2n fifth through holes 500 and the fourth through holes 400 are staggered by an angle. In this embodiment, n represents a natural number 1, 2, 3, 4...; in this application, n = 1, meaning that two third through holes 300 and two fourth through holes 400 are provided, and two fifth through holes 500 are also provided; however, the fifth through hole 500 is offset from the third through hole 300 and the fourth through hole 400 by 90°; here, the third through hole 300 and the fourth through hole 400 are set at the same angle, but the fifth through hole 500 is offset from the third through hole 300 and the fourth through hole 400 by a different angle, mainly for cooperation with the small valve core 13 structure. Please refer to... Figure 11 As shown, when n=2, the angles of each through hole are designed as equal-angle rings.

[0052] Please see Figure 10 As shown, the small valve core 13 has a hollow structure with an opening on one side. This can be understood as one end of the small valve core 13 being blocked, and the other end being open. The small valve core 13 is built inside the large valve core 12 and connected to the second motor 22. Specifically, the blocked end is connected to the second motor 22, allowing the small valve core 13 to rotate under the action of the second motor 22. 2n sixth through holes 600 and 2n seventh through holes 700 are provided on the outer surface of the small valve core 13. A third annular groove t is provided between the sixth and seventh through holes 600. A first notch 601 is provided between every two adjacent sixth through holes 600, and a second notch 701 is provided between every two adjacent seventh through holes 700. The first notch 601 and the second notch 701 are directly opposite each other and connected to the third annular groove t. The sixth through hole 600, the first notch 601, and the second annular groove i correspond to each other, and the seventh through hole 700, the second notch 701, and the second annular groove k correspond to each other. Please refer to [link to relevant documentation]. Figure 12 The figure shows the design diagram of the through holes (sixth through hole 600 and seventh through hole 700) with equal angles when n=2.

[0053] In this embodiment, by making the above design to the structure of the large valve core 12 and the small valve core 13, after the small valve core 13 is fitted into the large valve core 12, the hollow cavity of the small valve core 13 is always connected to the second annular groove m through the second through hole 200, and the second annular groove m is always connected to the oil inlet P through the first through hole 100 in the first annular groove a. It can be understood that no matter how the large valve core 12 and the small valve core 13 rotate, the oil inlet P will always be connected to the hollow cavity of the small valve core 13, ensuring that the hollow cavity of the small valve core 13 is always filled with hydraulic oil.

[0054] Taking the extension movement of the telescopic shaft of hydraulic cylinder 30 as an example during the specific rotation process:

[0055] The first motor 21 drives the large valve core 12 to rotate forward, and the third through hole 300 will gradually connect with the sixth through hole 600. At the same time, the fifth through hole 500 connects with the second notch 701, so that the fifth through hole 500 connects with the fourth through hole 400 through the channel formed between the second notch 701 and the third annular groove t. At this time, the hydraulic oil in the hollow cavity of the small valve core 13 flows to the working oil port A through the connected channel, until it flows to the oil passage A interface at the end of the cylinder body in the hydraulic cylinder. The oil is injected into the rear half of the hydraulic cylinder, causing the extension shaft of the hydraulic cylinder to start to extend. The hydraulic oil in the front half of the hydraulic cylinder is squeezed and flows out from the oil passage B interface at the front end of the cylinder body. This B interface is connected to the working oil port B through a pipe. The working oil port B is connected to the fifth through hole 500. The oil will enter the hydraulic station through the return oil port, thereby ensuring the connection of the entire oil circuit and enabling the hydraulic oil to complete the circulation flow. When the extension shaft of the hydraulic cylinder moves, the sensor on the extension shaft receives a position movement signal. This signal drives the second motor 22 to start rotating as well, so that the rotation direction of the small valve core 13 is the same as that of the large valve core 12. At one pulse frequency, the small valve core 13 will rotate at the same angle as the large valve core 12, thus interrupting the connected oil circuit. When the control signal of the first motor continues to be sent, the large valve core 12 continues to rotate, so that the interrupted oil circuit is reconnected, and the extension shaft of the hydraulic cylinder continues to move. The sensor on the extension shaft receives a position movement signal again and controls the second motor to rotate, so that the small valve core 13 rotates to catch up with the large valve core 12 to block the oil circuit. That is, the first motor 21 always drives the large valve core to rotate in the forward direction to ensure the smooth flow of the oil circuit, while the second motor 22 always drives the small valve core 13 to rotate in the same direction to catch up with the large valve core 12, thus completing the blockage of the oil circuit and causing the oil circuit to be disconnected.

[0056] Under the continuous impact of the control pulse signal, the hydraulic cylinder can be supplied with a small amount of oil through a continuous cycle of oil circuit opening, oil circuit closing, oil circuit opening, oil circuit closing, etc., in a short period of time, thus achieving micro-feeding of the hydraulic cylinder. Under the state of micro-feeding and micro-feeding of the hydraulic cylinder, the control pulse stops being sent until the telescopic shaft reaches the set position, the large valve core 12 stops rotating, the telescopic shaft of the hydraulic cylinder stops moving, the small valve core 13 also stops rotating, and the telescopic shaft stops at the set position.

[0057] When the telescopic shaft needs to retract, the first motor 21 and the second motor 22 need to reverse.

[0058] Specifically, the first motor 21 drives the large valve core 12 to reverse, and the fifth through hole 500 gradually connects with the seventh through hole 700. At the same time, the third through hole 300 connects with the first notch 601, so that the third through hole 300 connects with the fourth through hole 400 through the channel formed between the first notch 601 and the third annular groove t. At this time, the hydraulic oil in the hollow cavity of the small valve core 13 flows to the working oil port B through the connected channel, until it flows to the B interface in the hydraulic cylinder. Through reverse circulation, it causes the telescopic shaft to retract, and finally returns to the return oil port T through the working oil port A, the third through hole 300, the first notch 601, the third annular groove t and the fourth through hole 400. Of course, during the retraction of the telescopic shaft, the second motor 22 still drives the small valve core 13 to reverse and catch up with the large valve core 12, so that the oil circuit in it continuously circulates between open circuit, closed circuit, open circuit, closed circuit, etc., to ensure micro-oil supply and micro-retraction.

[0059] Through the above structural design, the motion accuracy of the hydraulic cylinder is ensured by rotation. Actual measurements show that the hydraulic cylinder controlled by the hydraulic valve designed in this scheme exhibits a motion deviation of less than 0.03mm. In this application, the small valve core 13 follows the rotation of the large valve core 12 to achieve continuous circulation of the oil circuit's opening and closing. However, in practical applications, the small valve core 13 can be started first, and the design structure of the large valve core 12 following the small valve core 13 can achieve the same effect as the above embodiment.

[0060] It is important to note that the speed of the first motor (either the first motor 21 or the second motor 22) determines the opening of the oil passage inside the large and small valve cores in a single cycle, thus determining the oil intake in a single control cycle. The oil intake in a single cycle determines the speed of the telescopic shaft. This is because the higher the rotational speed, the larger the opening of the oil passage is formed instantaneously, and the increased instantaneous oil intake will significantly increase the speed of the telescopic shaft. To differentiate them, different distinctive designs are made for the different through-hole structures; that is, the third through-hole 300, the fifth through-hole 500, the sixth through-hole 600, and the seventh through-hole 700 are all square through-holes.

[0061] In this application, a unique design is made to the structure of the hydraulic valve 10, valve core body 11, large valve core 12, and small valve core 13. The large valve core 12 and small valve core 13 are independently controlled by the first motor 21 and the second motor 22, so that the large valve core 12 and small valve core 13 can rotate independently within the valve core body. This completes the continuous connection (i.e., connection), closure (i.e., disconnection), reconnection, and high-speed cycle of the oil circuit, thereby realizing micro-oil supply to the hydraulic cylinder and micro-feed control of the hydraulic cylinder piston. High-precision control of the hydraulic cylinder movement is achieved through the mutual rotation of the valve cores.

[0062] Compared to digital hydraulic cylinders, this invention features fully closed-loop control with a short intermediate transmission chain, resulting in high control precision. Furthermore, its simple structure and control method allow for direct integration with any motion controller, ensuring high motion accuracy. Compared to proportional servo valves, this invention eliminates the need for complex control algorithms and independent control systems, offering a simpler control method and direct integration with any motion controller, while maintaining high motion precision. It also has lower requirements for oil quality and temperature, making it economical and reliable.

[0063] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A servo valve control system based on valve core rotation, characterized in that: Includes a hydraulic valve (10), a first motor (21), a second motor (22), a hydraulic cylinder (30), a first actuator (41), and a second actuator (42); A valve core body (11) is provided inside the hydraulic valve (10), a large valve core (12) is installed inside the valve core body (11), and a small valve core (13) is installed inside the large valve core (12). The large valve core (12) is connected to the first motor (21), and the small valve core (13) is connected to the second motor (22). The hydraulic valve (10) is provided with an oil inlet (P), an oil return port (T), a working oil port (A) and a working oil port (B); the oil inlet (P), the oil return port (T), the working oil port (A) and the working oil port (B) are respectively connected to the inner cavity of the valve core body (11); The hydraulic cylinder (30) is provided with cylinder A port (31) and cylinder B port (32), the cylinder A port (31) is connected to the working oil port (A), and the cylinder B port (32) is connected to the working oil port (B); The first driver (41) drives the first motor (21) to operate, and the second driver (42) drives the second motor (22) to operate. A displacement sensor (43) is provided at the front end of the telescopic shaft of the hydraulic cylinder (30). The displacement sensor (43) is electrically connected to the second driver (42). The displacement sensor (43) can feed back the displacement signal of the displacement sensor (43) to the second driver (42) so that the second driver (42) drives the second motor (22) to operate. The valve core (11) is a circular hollow structure with openings at both ends. The outer surface of the valve core (11) is provided with four parallel first annular grooves a, b, c and d along its axial direction. The first annular grooves a, b, c and d are respectively connected to the oil inlet (P), working oil port (A), return oil port (T) and working oil port (B) on the hydraulic valve (10). At least one first through hole (100) is provided at the bottom of each of the first annular grooves a, b, c and d. The large valve core (12) is a circular hollow structure with an opening on one side. The outer surface of the large valve core (12) is provided with four parallel second annular grooves m, i, j and k along its axial direction. The second annular grooves m, i, j and k are respectively connected to the first annular grooves a, b, c and d. At least one second through hole (200) is provided at the bottom of the second annular groove m; 2n third through holes (300) are evenly arranged at equal angles at the bottom of the second annular groove i; 2n fourth through holes (400) are evenly arranged at equal angles at the bottom of the second annular groove j; the third through holes (300) and the fourth through holes (400) are arranged in the same direction and correspond one to one. The bottom of the second annular groove k is provided with 2n fifth through holes (500) at equal angles, and the 2n fifth through holes (500) are offset from the fourth through hole (400) by an angle difference. The small valve core (13) is a circular hollow structure with an opening on one side. 2n sixth through holes (600) and 2n seventh through holes (700) are provided on the outer surface of the small valve core (13). A third annular groove (t) is also provided between the sixth through hole (600) and the seventh through hole (700). The third through hole (300), the fifth through hole (500), the sixth through hole (600) and the seventh through hole (700) are all through holes with a square structure. A first notch (601) is provided between every two adjacent sixth through holes (600), and a second notch (701) is provided between every two adjacent seventh through holes (700). The first notch (601) and the second notch (701) are directly opposite each other and connected to the third annular groove (t). The sixth through hole (600), the first notch (601) and the second annular groove i correspond to each other, and the seventh through hole (700) and the second notch (701) correspond to each other.

2. The servo valve control system based on valve core rotation according to claim 1, characterized in that: The large valve core (12) is provided with a first axial adjustment sleeve (14) on the side facing the first motor (21), and the small valve core (13) is provided with a second axial adjustment sleeve (15) on the side facing the second motor (22). The first axial adjustment sleeve (14), the large valve core (12), the small valve core (13), and the second axial adjustment sleeve (15) are coaxially installed.

3. The servo valve control system based on valve core rotation according to claim 2, characterized in that: The large valve core (12) has a first coupling (17) on its end face facing the first motor (21), and the output shaft of the first motor (21) is connected to the large valve core (12) through the first coupling (17); the small valve core (13) has a sealing sleeve (16) on its side facing the second motor (22), and the second axial adjustment sleeve (15) is located between the sealing sleeve (16) and the second motor (22).

4. The servo valve control system based on valve core rotation according to claim 1, characterized in that: Both the first motor (21) and the second motor (22) are servo motors or stepper motors.

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