Servo valve control system based on valve element rotation

Abstract

The device comprises a hydraulic valve, a first motor, a second motor, a hydraulic cylinder, a first driver and a second driver. A valve element body is arranged in the hydraulic valve, a large valve element is arranged in the valve element body in a sleeved mode, a small valve element is arranged in the large valve element in a sleeved mode, the large valve element is connected with a first motor, and the small valve element is connected with a second motor. The first driver drives the first motor to operate, the second driver drives the second motor to operate, a displacement sensor is arranged at the front end of a telescopic shaft of the hydraulic cylinder, the displacement sensor is electrically connected with the second driver, and the displacement sensor can feed back displacement signals of the displacement sensor to the second driver so that the second driver can drive the second motor to operate. By adopting the setting of the control system, the servo valve control system not only can realize closed-loop control and improve the control precision, but also can be applied to profiling movement such as constant pressure, and the use universality is further expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of servo valve control system design, and in particular relates to a servo valve control system based on valve core rotation. Background Art

[0002] In the prior art, there are generally two ways to control hydraulic cylinders, namely digital cylinders and servo valves. However, in a large number of practices, it is found that both of the existing technologies have obvious disadvantages in position control of hydraulic cylinders:

[0003] First, when using a digital cylinder to accurately control the position of a hydraulic cylinder, the position control is achieved by the movement of the valve core in the system, and the movement of the valve core is completely dependent on the transmission of the screw nut width. This transmission form inevitably has a transmission gap. At the same time, as the use time increases, the wear of the nut width will increase, and its gap will also become larger and larger. Due to the existence of the transmission gap, the position control of the hydraulic cylinder will produce a large displacement deviation. At the same time, this transmission method has very high requirements for the valve core, transmission screw, and servo motor, high manufacturing cost, and short service life.

[0004] Second, when using a servo valve to achieve hydraulic cylinder position control, the opening of the valve core is very small, and the viscosity, temperature, density, and purity of the oil have a very large impact on the displacement of the cylinder. All hydraulic control systems using electro-hydraulic servo valves are generally equipped with complex hydraulic stations to ensure high-standard use conditions for hydraulic oil. At the same time, since this control requires real-time detection of the hydraulic oil, the hydraulic state has a relatively complex control algorithm for the motion control of the hydraulic cylinder, so the servo valve is equipped with a dedicated independent servo control unit, which makes the servo valve expensive and has high maintenance costs. If it needs to be connected to a general control system, the control system needs to be customized. Summary of the invention

[0005] In view of the above problems, the present invention has redesigned a new servo valve control system based on valve core rotation. By adopting the settings of the above control system, the servo valve control system can not only realize closed-loop control and improve the control accuracy, but also be applicable to contour-like movements such as ensuring constant pressure, thereby further expanding its wide range of uses.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[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 driver and a second driver;

[0008] A valve core body is arranged in the hydraulic valve, a large valve core is sleeved in the valve core body, a small valve core is sleeved in the large valve core, the large valve core is connected to the first motor, and the small valve core is connected to the 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, the oil return port, the working oil port A and the working oil port B are respectively connected to the inner cavity of the valve core body;

[0010] The hydraulic cylinder is provided with a cylinder port A and a cylinder port B, the cylinder port A is connected to the working oil port A, and the cylinder port B is connected to the 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 arranged 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 a displacement signal of the displacement sensor to the second driver so that the second driver drives the second motor to operate.

[0012] As 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, and the first axial adjustment sleeve, the large valve core, the small valve core and the second axial adjustment sleeve are coaxially installed.

[0013] As a preferred embodiment of the present invention, a first coupling is arranged on the end surface 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 arranged 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] As a preferred embodiment of the present invention, the valve core body is a circular hollow structure with openings at both ends, and the outer surface of the valve core body is provided with four parallel first ring grooves a, b, c and d along its axial direction, and the first ring grooves a, b, c and d are respectively connected to the oil inlet, working oil port A, oil return port and working oil port B on the hydraulic valve, and at least one first through hole is provided at the bottom of the first ring 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, and the outer surface of the large valve core is provided with four parallel second ring grooves m, second ring groove i, second ring groove j and second ring groove k along its axial direction, and the second ring groove m, second ring groove i, second ring groove j and second ring groove k are respectively connected with the first ring groove a, first ring groove b, first ring groove c and first ring groove d.

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

[0017] As a preferred embodiment of the present invention, 2n fifth through holes are evenly arranged at equal angles at the bottom of the second annular groove k, and the 2n fifth through holes are staggered with 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-side opening, and 2n sixth through holes and 2n seventh through holes are arranged on the outer surface of the small valve core. A third annular groove t is also arranged between the sixth through hole and the seventh through hole, and 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 arranged between each two adjacent sixth through holes, and a second notch groove is arranged between each two adjacent seventh through holes, the first notch groove is directly opposite to the second notch groove and is connected to the third annular groove t, the sixth through hole and the first notch correspond to the second annular groove i, and the seventh through hole and the second notch groove correspond to the second annular groove k.

[0020] As a preferred solution of this 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 the present invention adopts the setting of the above control system, so that the servo valve control system can not only realize closed-loop control and improve the control accuracy, but also can be used in contour-like movements such as ensuring constant pressure, thereby further expanding the wide range of uses. At the same time, compared with the digital cylinder, the intermediate transmission chain is short and the control accuracy is high. The present invention has a simple structure and a simple control method, can be directly connected to any motion controller, and has high motion accuracy. Compared with the proportional servo valve, the present invention does not require a complex control algorithm or an independent control system, has a simple control method, can be directly connected to any motion controller, and has high motion accuracy. At the same time, it has low requirements on oil quality, temperature, etc., and is economical and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0024] Figure 1 It is a schematic diagram of the overall structure of the servo valve control system based on valve core rotation of the present invention;

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

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

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

[0028] Figure 5 It is a schematic diagram of the matching structure of the valve core body, the large valve core and the small valve core in the present invention;

[0029] Figure 6 It is a structural schematic diagram of the front end surface of the hydraulic valve in the present invention;

[0030] Figure 7 It is a structural schematic diagram of the rear end face of the hydraulic valve in the present invention;

[0031] Figure 8 It is a schematic diagram of the overall structure of the valve core body in the present invention;

[0032] Fig. 9 This is a schematic diagram of the structure of the large valve core when n=1 in the present invention;

[0033] Fig.10 This is a schematic diagram of the structure of the small valve core when n=1 in the present invention;

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

[0035] Fig.12 This is a schematic diagram of the structure of the small valve core when n=2 in the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] See also Figures 1 to 3As shown, the embodiment of the present 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 provided in the hydraulic valve 10, a large valve core 12 is sleeved in the valve core body 11, a small valve core 13 is sleeved in 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. An oil inlet P, an oil return port T, a working oil port A and a working oil port B are provided on the hydraulic valve 10; 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, and a cylinder A port 31 and a cylinder B port 32 are provided on the hydraulic cylinder 3, 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 a 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 rotation control is performed by separate drivers (the first driver 41 and the second driver 42), thereby ensuring the independence of the rotation of the large and small valve cores.

[0038] Specifically, in this embodiment, the displacement sensor 43 is used to enable the second motor 22 to rotate following the first motor 21. The specific method is: when the first motor 21 is started to make the oil circuit open, the telescopic shaft of the hydraulic cylinder 30 will extend, and the movement of the telescopic shaft will cause the displacement sensor 43 to generate a displacement signal, and transmit the displacement signal to the second driver 42. The second driver 42 drives the second motor 22 to start, so that the small valve core 13 catches up with the rotation of the large valve core 12 to disconnect the oil circuit. By using the coordination between the displacement sensor 43 and the driver, the follow-up movement between the large valve core 12 and the small valve core 13 can be better guaranteed, and the continuous circulation of the oil circuit between the passage and the disconnection can be guaranteed, which has a great promoting effect on the movement accuracy of the telescopic shaft.

[0039] To further optimize this embodiment, the servo valve control system based on valve core rotation also includes a motion controller 44, the displacement sensor 43 is also electrically connected to the motion controller 44, the motion controller 44 is electrically connected to the first driver 41, and the motion controller 44 transmits a control signal to the first driver 41 according to the displacement signal of the displacement sensor 43. When the telescopic shaft moves (it can be an extension movement or a retraction movement), the displacement sensor 43 located at the head of the telescopic shaft will send a position pulse signal, and the pulse signal will be divided into two paths, one of which is connected to the position detection interface of the motion controller 44 to connect the motion signal of the telescopic shaft to the motion controller 44, and control the first motor 21 to stop rotating after the telescopic shaft moves to the position; the other is connected to the second driver 42 to control the second motor 22 to keep following the first motor 21. Through the design of the above structure, the closed-loop control of the movement position of the telescopic shaft is guaranteed, and higher movement accuracy is obtained.

[0040] Of course, it is optional to install a pressure sensor (not shown) at the front end of the telescopic shaft of the hydraulic cylinder. The pressure sensor is electrically connected to the motion controller 44 to feedback the pressure data signal at the front end of the telescopic shaft. By feedback of the pressure, the pressure value is incorporated into the motion control algorithm, and the pressure control at the front end of the telescopic shaft can be realized. This control method is particularly suitable for motion profiling. The specific profiling motion can be understood as: presetting the pressure range at the front end of the telescopic shaft; during the extension or retraction of the telescopic shaft, when the pressure sensor detects that the pressure generated by the telescopic shaft acting on an object exceeds the preset pressure range, the pressure sensor transmits the signal to the motion controller 44, so that the telescopic shaft can move appropriately in the opposite direction to reduce the pressure to the preset range and ensure the constant pressure. By adopting the above control system settings, the servo valve control system can not only realize closed-loop control and improve the control accuracy, but also be applicable in profiling motions such as ensuring constant pressure, and the wide range of use can be further expanded. Through such a new design, the servo valve system provided by the present application has a higher motion accuracy. At the same time, through the reasonable mutual cooperation between the internal valve cores, the movement speed of the piston of the hydraulic cylinder 30 can be controlled by changing the rotation speed of the motor (the first motor 21 and the second motor 22).

[0041] See also Figure 3 and Figure 4As shown, a mounting flange 33 and a connecting piece 34 are respectively provided on the left and right sides of the hydraulic valve 10, and the mounting flange 33 and the connecting piece 34 are provided to facilitate the installation and fixation of the first motor 21 and the second motor 22. At the same time, in order 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 installed. The large valve core 12 is adjusted in the axial direction by the first axial adjustment sleeve 14, and the small valve core 13 is adjusted in the axial direction by the second axial adjustment sleeve 15, so as to ensure the accurate positioning and installation of the large and small valve cores.

[0042] In this embodiment, a sealing sleeve 16 is further provided on the side of the small valve core 13 facing the second motor 22, and the second axial adjustment sleeve 15 is located between the sealing sleeve 16 and the second motor 22. A first coupling 17 having a blocking and connecting function is provided on the end surface 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 having a blocking and connecting function is provided on the end surface 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. At the same time, in order to further reduce the load of the motor, an axial bearing can be installed between the large valve core 12, the small valve core 13 and the corresponding adjustment sleeve 14 and the sealing sleeve 16 to reduce the friction force when the valve core moves, reduce the load of the motor, improve the dynamic response characteristics of the motor, and thus improve the movement accuracy of the hydraulic cylinder.

[0043] In this embodiment, a unique design is made for the structure of the hydraulic valve 10, the valve core body 11, the large valve core 12 and the small valve core 13, and the large valve core 12 and the 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 the small valve core 13 can rotate independently within the valve core body; the continuous connection (i.e., connection), closure (i.e., disconnection), reconnection and closure of the oil circuit are completed, thereby achieving micro-oil supply to the hydraulic cylinder, and then achieving micro-feed control of the hydraulic cylinder piston, and high-precision control of the hydraulic cylinder movement is achieved by the mutual rotation of the valve cores.

[0044] See also 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 arranged in the hydraulic valve 10, a large valve core 12 is installed in the valve core body 11, and a small valve core 13 is installed in 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 valve core body 11 is a circular hollow structure with openings at both ends. A plurality of first annular grooves are opened along the axial direction on the outer surface of the valve core body 11, and at least one first through hole 100 is opened at the bottom of each first annular groove. The large valve core 12 is a circular hollow structure with a single-side opening, and a plurality of second annular grooves are axially provided on the outer surface of the large valve core 12, and each of the second annular grooves is connected to the first annular grooves respectively. The small valve core 13 is a circular hollow structure with a single-side opening, and a plurality of sixth through holes 600 and a plurality of seventh through holes 700 are provided on the outer surface of the small valve core 13, and a third annular groove t is further provided between the sixth through hole 600 and the seventh through hole 700, and the sixth through hole 600 and the seventh through hole 700 respectively correspond to the second annular grooves.

[0045] See also Figures 1 to 7 As shown, the hydraulic valve 10 and the first motor 21 and the second motor 22 are arranged on the left and right end surfaces of the hydraulic valve 10. The servo valve movement is coordinated by 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. The specific first motor 21 and the second motor 22 can be a servo motor or a stepper motor. That is, the servo valve proposed in this application has strong applicability and can be applied to different motors. For the sake of convenience, the servo motor is used as an example for specific demonstration in this solution.

[0046] See also Figure 5 As shown, the hydraulic valve 10 is composed of four parts, specifically the valve body and valve core body 11 located on the outermost side, the small valve core 13 located on the innermost side and the large valve core 12 between the valve core body 11, that is, the valve core body 11 is sleeved on the outer surface of the large valve core 12, the large valve core 12 is sleeved on the outer surface of the small valve core 13, and the valve core body 11, the large valve core 12 and the small valve core 13 are all arranged inside the valve body. In this application, the structural design of the valve body, valve core body 11, the large valve core 12 and the small valve core 13 is the main innovation point. Through the clever 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 realize the feeding and delivery of the hydraulic oil during the rotation of the large valve core 12 and the small valve core 13. The structure of each component is introduced in detail below:

[0047] See also Figures 2 to 7As shown, the structure of the hydraulic valve 10 is a square structure, and an oil inlet P and an oil return port T are provided on the front end face of the hydraulic valve 10, and a working oil port A and a working oil port B are also provided on the rear end face of the hydraulic valve 10, that is, the oil inlet P and the oil return port T are located on the same side of the end face of the hydraulic valve 10, and the working oil port A and the working oil port 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 oil return port T, the working oil port A and the working oil port B are provided can be different end faces, or can be on the same end face, and the specific implementation can be appropriately improved and designed according to the actual situation.

[0048] See also Figure 8 As shown, the valve core body 11 is arranged inside the hydraulic valve 10, and the valve core body 11 is a hollow structure with openings on both sides. It can be understood that the valve core body 11 is a circular cylindrical structure, and four parallel first annular grooves a, b, c, and d are opened on the outer surface of the valve core body 11 along its axial direction. The first annular grooves a, b, c, and d are respectively connected to the oil inlet P, the oil return port T, the working oil port A, and the working oil port B on the hydraulic valve 10. Specifically, it can be understood that the first annular groove a corresponds to and is connected to the oil inlet P in position, the first annular groove b corresponds to and is connected to the working oil port A in position, the first annular groove c corresponds to and is connected to the oil return port T in position, and the first annular groove d corresponds to and is connected to the working oil port B in position. At the same time, in order to achieve connectivity, at least one first through hole 100 is opened at the bottom of the first annular groove a, the first annular groove b, the first annular groove c, and the first annular groove d described above. The first through hole 100 is mainly provided here to achieve connectivity with the internal large valve core 12.

[0049] See also Fig. 9As shown, the large valve core 12 is also a hollow structure, but the large valve core 12 is a hollow structure with a single-side opening, that is, one side of the large valve core 12 is a blocking structure, the large valve core 12 is built inside the valve core body 11, and the large valve core 12 is connected to the first motor 21. Here, the connection position is specifically that the blocked end of the large valve core 12 is connected to the first motor 21, so that under the rotation of the first motor 21, the large valve core 12 will rotate. Four parallel second annular grooves m, second annular grooves i, second annular grooves j, and second annular grooves k are opened on the outer surface of the large valve core 12 along its axial direction, and the second annular grooves m, second annular grooves i, second annular grooves j, and second annular grooves k are respectively connected to the first annular grooves a, first annular grooves b, first annular grooves c, and first annular grooves d. It can be understood that: 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 the first through hole 100 and the second through hole 200 can be one, and can also be set to two, three, four...; in this embodiment, in order to facilitate processing needs and optimize the structure, four first through holes 100 are respectively provided in the first annular groove a, the first annular groove b, the first annular groove c, and the first annular groove d, and the four first through holes 100 are arranged in an equal-angle 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-angle annular array in the second annular groove m.

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

[0052] See also Fig.10 As shown, the small valve core 13 has a hollow structure with one side open. It can also be understood that one end of the small valve core 13 is blocked and the other end is open. The small valve core 13 is built into the large valve core 12 and connected to the second motor 22. Specifically, the blocked end is connected to the second motor 22, so that the small valve core 13 can rotate under the action of the second motor 22. 2n sixth through holes 600 and 2n seventh through holes 700 are arranged on the outer surface of the small valve core 13. A third annular groove t is also arranged between the sixth through hole 600 and the seventh through hole 700. A first notch groove 601 is arranged between each two adjacent sixth through holes 600, and a second notch groove 701 is arranged between each two adjacent seventh through holes 700. The first notch groove 601 is directly opposite to the second notch groove 701 and is connected to the third annular groove t. The sixth through hole 600 and the first notch groove 601 correspond to the second annular groove i, and the seventh through hole 700 and the second notch groove 701 correspond to the second annular groove k. Please refer to Fig.12 As shown, when n=2, the through holes (the sixth through hole 600 and the seventh through hole 700) are designed in an equi-angled ring shape.

[0053] In this embodiment, by making the above design on the structure of the large valve core 12 and the small valve core 13, after the small valve core 13 is inserted into the large valve core 12, the hollow cavity of the small valve core 13 is always connected with the second annular groove m through the second through hole 200, and the second annular groove m is always connected with 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 with the hollow inner cavity of the small valve core 13, so as to ensure that the hollow cavity of the small valve core 13 is always filled with hydraulic oil.

[0054] In the specific rotation process, the extension movement of the telescopic shaft of the hydraulic cylinder 30 is taken as an example:

[0055] The first motor 21 drives the large valve core 12 to rotate forward, and the third through hole 300 will gradually communicate with the sixth through hole 600. At the same time, the fifth through hole 500 is correspondingly connected with the second notch groove 701, so that the fifth through hole 500 is connected with the fourth through hole 400 through the channel formed between the second notch groove 701 and the third ring 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 channel A interface located 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 telescopic shaft of the hydraulic cylinder to start to extend; the hydraulic oil in the front half of the hydraulic cylinder is squeezed and will flow out from the oil channel B interface located at the front end of the cylinder body. The B interface is connected to the working oil port B through a pipeline, and 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 connectivity of the entire oil circuit so that the hydraulic oil can complete the circulation flow. When the telescopic shaft of the hydraulic cylinder moves, the sensor on the telescopic shaft of the oil cylinder obtains a position movement signal, and the signal drives the second motor 22 to start rotating in the same way, so that the rotation direction of the small valve core 13 is the same as the rotation direction of the large valve core 12. At a pulse frequency, the small valve core 13 will rotate at the same angle as the large valve core 12, so that the connected oil circuit is interrupted; when the control signal of the first motor is continuously sent, the large valve core 12 continues to rotate, so that the interrupted oil circuit is connected again, and the telescopic shaft of the hydraulic cylinder continues to move; the sensor on the telescopic shaft of the oil cylinder obtains a position movement signal to control the rotation of the second motor again, 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 forward to ensure the smooth flow of the oil circuit, and 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, completes the blocking of the oil circuit, and breaks the oil circuit.

[0056] Under the continuous impact of the control pulse signal, through such continuous cycle of oil circuit access, oil circuit disconnection, oil circuit access, oil circuit disconnection... in a short time, micro-oil supply to the hydraulic cylinder can be achieved to realize micro-feed of the hydraulic cylinder; under the state of micro-oil supply and micro-feed of the hydraulic cylinder, until the telescopic shaft reaches the set position, the control pulse stops sending, 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 be retracted, the first motor 21 and the second motor 22 need to be reversed.

[0058] Specifically, the first motor 21 drives the large valve core 12 to reverse, and the fifth through hole 500 gradually communicates with the seventh through hole 700. At the same time, the third through hole 300 is correspondingly communicated with the first notch groove 601, so that the third through hole 300 is communicated with the fourth through hole 400 through the channel formed between the first notch groove 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, and through the reverse circulation flow, the telescopic shaft is prompted to retreat, and finally passes through the working oil port A, the third through hole 300, the first notch groove 601, the third annular groove t and the fourth through hole 400 to the oil return port T; of course, during the retreat 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 therein is constantly circulating in the passage, disconnection, passage, disconnection... to ensure micro-oil supply and micro-retreat.

[0059] Through the design of the above structure, the movement accuracy of the hydraulic cylinder is ensured by rotation. Through actual measurement, the hydraulic cylinder is controlled by the hydraulic valve designed in this scheme, and the movement deviation of the hydraulic cylinder is less than 0.03mm. In this application, the small valve core 13 catches up with the rotation of the large valve core 12 to achieve the continuous circulation of the oil circuit and the disconnection; however, in actual use, the rotation of the small valve core 13 can also be started first, and the design structure of the large valve core 12 catching up with the small valve core 13 can also achieve the same effect as the above embodiment.

[0060] It should be noted that the speed of the motor that is started first (the first motor 21 or the second motor 22) determines the opening of the oil circuit inside the large and small valve cores in a single cycle, thereby determining the amount of oil inlet in a single control cycle. The amount of oil inlet in a single cycle determines the speed of the telescopic shaft movement; this is because the greater the speed, the larger the oil circuit opening is formed in an instant, and the increase in the instantaneous oil inlet will significantly increase the speed of the telescopic shaft movement. In order to achieve distinction, different iconic designs are made for 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 through-holes with square structures.

[0061] In the present application, a unique design is made for the structure of the hydraulic valve 10, the valve core body 11, the large valve core 12 and the small valve core 13, and the large valve core 12 and the 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 the small valve core 13 can rotate independently within the valve core body; the continuous connection (i.e., connection), closure (i.e., disconnection), reconnection and high-speed circulation of the oil circuit are completed, thereby realizing micro-oil supply to the hydraulic cylinder, and then realizing micro-feed control of the hydraulic cylinder piston, and realizing high-precision control of the hydraulic cylinder movement by the mutual rotation of the valve cores.

[0062] Compared with the digital cylinder, the present invention is a full closed-loop control, with a short intermediate transmission chain and high control accuracy. In addition, the present invention has a simple structure and a simple control method, can be directly connected to any motion controller, and has high motion accuracy. Compared with the proportional servo valve, the present invention does not require a complex control algorithm or an independent control system, has a simple control method, can be directly connected to any motion controller, and has high motion accuracy. At the same time, it has low requirements on oil quality, temperature, etc., and is economical and reliable.

[0063] The above are only 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 in the protection scope of the present invention.

Claims

1. A servo valve control system based on valve core rotation, characterized in that: It comprises 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 arranged in the hydraulic valve (10), a large valve core (12) is sleeved in the valve core body (11), a small valve core (13) is sleeved in the large valve core (12), the large valve core (12) is connected to a first motor (21), and the small valve core (13) is connected to a 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 a cylinder A port (31) and a cylinder B port (32), wherein 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 arranged 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 a 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.

2. The servo valve control system based on valve core rotation according to claim 1, characterized in that: 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.

3. The servo valve control system based on valve core rotation according to claim 2, characterized in that: A first coupling (17) is arranged on the end surface 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) via the first coupling (17); a sealing sleeve (16) is arranged on the side of the small valve core (13) 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: The valve core body (11) is a circular hollow structure with openings at both ends. The outer surface of the valve core body (11) is provided with four parallel first annular grooves (a), first annular grooves (b), first annular grooves (c) and first annular grooves (d) along its axial direction. The first annular grooves (a), first annular grooves (b), first annular grooves (c) and first annular grooves (d) are respectively connected to the oil inlet (P), the working oil port (A), the oil return port (T) and the 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), first annular grooves (b), first annular grooves (c) and first annular grooves (d).

5. The servo valve control system based on valve core rotation according to claim 4, characterized in that: The large valve core (12) is a circular hollow structure with a single-side opening. 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).

6. The servo valve control system based on valve core rotation according to claim 5, characterized in that: 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); and 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.

7. The servo valve control system based on valve core rotation according to claim 6, characterized in that: 2n fifth through holes (500) are evenly arranged at equal angles at the bottom of the second annular groove (k), and the 2n fifth through holes (500) are staggered with respect to the fourth through hole (400) at different angles.

8. The servo valve control system based on valve core rotation according to claim 6, characterized in that: The small valve core (13) is a circular hollow structure with a single-side opening. 2n sixth through holes (600) and 2n seventh through holes (700) are arranged on the outer surface of the small valve core (13). A third annular groove (t) is also arranged 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.

9. The servo valve control system based on valve core rotation according to claim 8, characterized in that: A first notch groove (601) is provided between each adjacent two of the sixth through holes (600), and a second notch groove (701) is provided between each adjacent two of the seventh through holes (700). The first notch groove (601) and the second notch groove (701) are directly opposite to each other and connected to the third annular groove (t). The sixth through hole (600), the first notch groove (601) and the second annular groove (i) correspond to each other, and the seventh through hole (700), the second notch groove (701) and the second annular groove (k) correspond to each other.

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

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