Mechanical feedback digital cylinder and hydraulic control system

Abstract

The application discloses a mechanical feedback type digital cylinder and a hydraulic control system, and the mechanical feedback type digital cylinder comprises a cylinder body, a piston rod, a moving screw rod, a valve core assembly, a planetary reduction assembly and a driving piece, the piston rod is arranged in the cavity of the cylinder body, the tail end of the piston rod is provided with a push block, the moving screw rod is arranged on the cylinder body and is matched in the piston rod at one end and is threadedly matched with the piston rod, the valve core assembly comprises a valve body, a valve core and a valve core screw rod, the valve body is provided with a liquid supply port and a liquid return port which are respectively communicated with the cavities on the two sides of the push block, the valve core screw rod is threadedly matched with the valve core, and the valve body is provided with a limiting structure which can prevent the valve core from rotating, the planetary reduction assembly comprises an outer gear ring, a sun gear, a planet wheel and a planet support, the planet support is sleeved on the moving screw rod, the sun gear is sleeved on the valve core screw rod, and the driving piece is engaged with the outer side of the outer gear ring. The mechanical feedback type digital cylinder has high mechanical feedback precision, can accurately control the position of the piston rod, and the valve core is not prone to wear.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and more specifically, to a mechanical feedback digital cylinder and a hydraulic control system. Background Technology

[0002] The two most important actuators in a hydraulic system are the hydraulic cylinder and the hydraulic motor, with hydraulic cylinders being used more extensively than hydraulic motors. Currently, the control of hydraulic cylinders in hydraulic systems mainly includes directional control, speed control, and position control, among which position control is far more difficult than the other two.

[0003] There are two main methods for achieving position control of hydraulic cylinders in related technologies. One is the valve control method with electrical signal feedback, which generates an electrical signal by detecting the position of the piston rod and uses this signal to control the hydraulic valve. The other is the mechanical feedback control method, which consists of a hydraulic valve and a hydraulic cylinder as a whole and includes a mechanical feedback device, which is used to control the hydraulic valve.

[0004] The second control method is currently more advanced. For example, a digital cylinder consists of a stepper motor, a two-stage screw pair, a three-position four-way valve, and a hydraulic cylinder. However, in the mechanical feedback of digital cylinders in related technologies, the mechanical feedback dead zone is large due to the limitation of the thread lead by friction self-locking and the ball screw structure, resulting in low mechanical feedback accuracy and difficulty in accurately controlling the position of the piston rod. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a mechanical feedback digital cylinder. In this mechanical feedback digital cylinder, the valve core only moves in translation and does not rotate. When the piston rod moves at a constant speed, the valve core remains stationary, which reduces the wear of the valve core seal and improves the life of the digital cylinder. Furthermore, this application uses a planetary reduction gear assembly as the main body of mechanical feedback, which reduces the value of the mechanical feedback dead zone and improves the accuracy of mechanical feedback.

[0007] Embodiments of the present invention also propose a hydraulic control system.

[0008] The mechanical feedback digital cylinder of this invention includes: a cylinder body, a piston rod, and a movable lead screw. The piston rod is movably disposed within a cavity of the cylinder body, and the tail end of the piston rod is provided with a push block that seals against the inner wall of the cavity. The movable lead screw passes through the cylinder body, and one end of it is fitted into the piston rod and threadedly engaged with the piston rod. A valve core assembly includes a valve body, a valve core, and a valve core lead screw. The valve body is connected to the outside of the cylinder body and has a supply port communicating with one side cavity of the push block and a return port communicating with the other side cavity of the push block. A valve core is movably disposed within the valve body to control the synchronous opening and closing of the supply port and return port. The valve core screw passes through the valve core and is threadedly engaged with it. The valve body is provided with a limiting structure that prevents the valve core from rotating. A planetary reduction assembly and a drive component are also provided. The planetary reduction assembly includes an external gear ring, a sun gear, planet gears, and a planetary support for supporting the planet gears. The planetary support is sleeved on the movable screw, the sun gear is sleeved on the valve core screw, and the planet gears engage between the external gear ring and the sun gear. The drive component meshes with the outer side of the external gear ring.

[0009] The mechanical feedback digital cylinder of this invention uses a planetary reduction gear assembly as the main body of the mechanical feedback structure. The planetary support is sleeved on the movable lead screw that is threaded with the piston rod, and the sun gear is sleeved on the valve core lead screw that is threaded with the valve core. The driving component can drive the sun gear to rotate through the external gear ring, thereby driving the valve core lead screw to rotate. The valve core lead screw can drive the valve core to open linearly to control the pressure change on both sides of the piston rod, thereby controlling the movement of the piston rod. The movement of the piston rod can drive the movable lead screw to rotate, thereby driving the planetary support to reverse. The reverse rotation of the planetary support can cooperate with the driving component to drive the external gear ring to provide feedback to the sun gear, thereby controlling the valve core lead screw to drive the valve core to move, realizing the mechanical feedback control process. In addition, compared with the prior art, this application uses the valve core lead screw in conjunction with the limiting structure in the valve body to drive the valve core to only move linearly without rotating through the lead screw transmission. When the piston rod moves at a constant speed, the valve core remains stationary, reducing the wear of the valve core seal and improving the life of the digital cylinder. Furthermore, this application uses a planetary reduction gear assembly as the main body of the mechanical feedback, reducing the value of the mechanical feedback dead zone and improving the accuracy of the mechanical feedback.

[0010] In some embodiments, the mechanical feedback digital cylinder further includes a threaded sleeve, the threaded sleeve including a cylindrical body with internal threads and an annular edge surrounding the outer periphery of the cylindrical body, the cylindrical body fitting inside the piston rod and sleeved on the movable lead screw, the annular edge abutting the side of the piston rod facing the valve core assembly and connected to the piston rod by screws.

[0011] In some embodiments, the cylinder body has a first receiving groove on the outer side facing the valve core assembly, the protruding end of the movable lead screw passes through the cylinder body and extends into the first receiving groove, and the planetary support has a sleeve portion that fits into the first receiving groove, the sleeve portion being sleeved on the protruding end of the movable lead screw.

[0012] In some embodiments, the inner side of the cylinder is provided with a second receiving groove opposite to the first receiving groove, the moving lead screw passes through the second receiving groove, and the second receiving groove is provided with a first bearing supporting the moving lead screw, and the first receiving groove is provided with a second bearing supporting the sleeve portion.

[0013] In some embodiments, the movable lead screw has a limiting protrusion located on the side of the first bearing opposite to the second bearing, and the first bearing can abut against the limiting protrusion.

[0014] In some embodiments, the limiting structure is an end cap, which is mounted on the valve body and faces the end of the valve core away from the valve core screw. The side of the end cap facing the valve core is provided with a limiting groove of a certain length in the moving direction of the valve core, and the end of the valve core facing the end cap is fitted into the limiting groove.

[0015] In some embodiments, the inner wall surface of the limiting groove includes two opposing planes, and the outer peripheral surface of the end of the valve core facing the end cap is in contact with both planes.

[0016] In some embodiments, the valve core assembly is a three-position four-way valve.

[0017] In some embodiments, a third bearing is provided in the valve body for supporting the valve core screw.

[0018] The hydraulic control system of this invention includes a mechanical feedback digital cylinder as described in the above embodiments.

[0019] The hydraulic control system of this invention, by employing the aforementioned mechanical feedback digital cylinder, achieves high control precision, minimal valve core wear, long service life, and high system reliability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the mechanical feedback digital cylinder according to the present invention.

[0021] Figure 2 This is an assembly diagram of the moving lead screw, planetary reduction assembly, valve core lead screw, and valve core of the mechanical feedback digital cylinder according to the present invention.

[0022] Figure label:

[0023] Cylinder body 1, piston rod 2, push block 21, moving screw 3, limiting convex ring 31, valve body 4, liquid supply port 41, liquid return port 42, liquid inlet port 43, unloading port 44, valve core 5, valve core screw 6, end cover 7, external gear ring 8, planetary gear 9, planetary support 10, sun gear 11, threaded sleeve 12, first bearing 13, second bearing 14, third bearing 15, drive component 16. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] like Figure 1 and Figure 2 As shown, the mechanical feedback digital cylinder of the present invention includes a cylinder body 1, a piston rod 2, a moving lead screw 3, a valve core 5 assembly, a planetary reduction gear assembly, and a drive component 16.

[0026] Specifically, such as Figure 1 and Figure 2 As shown, the piston rod 2 is movably inserted into the cavity of the cylinder 1, and the tail end of the piston rod 2 is provided with a push block 21 that is in sealing contact with the inner wall of the cavity. The moving screw 3 is inserted into the cylinder 1, and one end of it is fitted into the piston rod 2 and threadedly engaged with the piston rod 2. The valve core 5 assembly includes a valve body 4, a valve core 5, and a valve core screw 6. The valve body 4 is connected to the outside of the cylinder 1 and is opposite to the protruding end of the moving screw 3. The valve body 4 has a liquid supply port 41 communicating with one side cavity of the push block 21 and a liquid return port 42 communicating with the other side cavity of the push block 21. The valve core 5 is movably inserted into the cylinder 1. The valve body 4 is dynamically installed to control the synchronous opening and closing of the supply port 41 and the return port 42. The valve core screw 6 passes through the valve core 5 and is threadedly engaged with the valve core 5. The valve body 4 is provided with a limiting structure that can prevent the valve core 5 from rotating. The planetary reduction assembly includes an outer gear ring 8, a sun gear 11, planet gears 9 and a planetary support 10 for supporting the planet gears 9. The planetary support 10 is sleeved on the moving screw 3, the sun gear 11 is sleeved on the valve core screw 6, and the planet gears 9 are engaged between the outer gear ring 8 and the sun gear 11. The drive member 16 meshes with the outer side of the outer gear ring 8.

[0027] For ease of understanding, Figure 1 and Figure 2 The following example illustrates the control and mechanical feedback process of the digital cylinder in this application.

[0028] For example, the position control process of the piston rod 2 forward includes: the output shaft of the drive motor (drive component 16) rotates in the positive direction and is transmitted to the sun gear 11 through the external gear ring 8 and planetary gear 9 in sequence to drive the sun gear 11 to rotate. The rotation of the sun gear 11 can drive the valve core screw 6 to rotate. Since the valve core screw 6 is threaded with the valve core 5 and the valve body 4 is provided with a limiting structure that can restrict the rotation of the valve core 5, the rotation of the valve core screw 6 can drive the valve core 5 to move to the left to open the liquid supply port 41 and the liquid return port 42. At this time, the liquid supply port 41 is connected to the liquid inlet port 43 on the valve body 4, and the liquid return port 42 is connected to the unloading port 44 on the valve body 4. Then the liquid supply port 41 can supply liquid to the cavity on the right side of the push block 21, and at the same time, the liquid in the cavity on the left side of the push block 21 will flow back to the liquid tank through the liquid return port 42 and the unloading port 44. Then, under the action of pressure difference, the piston rod 2 can move forward to the left.

[0029] Furthermore, as the piston rod 2 moves, due to the threaded engagement between the piston rod 2 and the moving lead screw 3, the piston rod 2 will drive the moving lead screw 3 to rotate. The planetary support 10 sleeved on the moving lead screw 3 will drive the planetary gear 9 to rotate in the opposite direction. Thus, for different working conditions, it is necessary to control the operating state of the drive motor. For example, when it is necessary to control the piston rod 2 to move a certain stroke and maintain it in a fixed position, the drive motor can be stopped. The planetary gear 9 can drive the sun gear 11 to reverse, thereby driving the valve core lead screw 6 to reverse. Then, by utilizing the threaded engagement between the valve core lead screw 6 and the valve core 5, the valve core 5 is driven to move to the right to close the liquid supply port 41 and the liquid return port 42. The cavities on both sides of the push block 21 restore pressure balance, and the piston rod 2 stops moving.

[0030] For example, if it is necessary to control the piston rod 2 to move forward continuously at a certain speed, the drive motor can be controlled to continue running. In this case, the external gear ring 8 and planetary gears 9 can jointly control the rotation of the sun gear 11. Thus, by controlling the output power of the drive motor, the forward speed of the piston rod 2 can be adjusted. For example, when it is necessary to control the piston rod 2 to move forward at a higher speed, the output power of the drive motor can be increased, so that the movement speed of the piston rod 2 does not reach the speed corresponding to the angular velocity of the output shaft of the drive motor. Since the drive motor drives the gear ring to rotate in the positive direction, the piston rod 2 drives the planetary gears 9 to rotate in the opposite direction. At this time, the sun gear 11 will continue to rotate in the positive direction, and the valve core 5 will continue to move to the left, further increasing the valve opening. This will increase the pressure difference on both sides of the push block 21, and the piston rod 2 will accelerate to the left until the movement speed of the piston rod 2 reaches the speed corresponding to the angular velocity of the output shaft of the drive motor. At this time, the rotation of the planetary gears 9 and the external gear ring 8 cancel each other out, the valve core 5 stops moving, the valve core 5 remains open, and the piston rod 2 moves forward to the left at a higher speed.

[0031] For example, when it is necessary to control the piston rod 2 to move forward at a lower speed, the output power of the drive motor can be reduced, so that the movement speed of the piston rod 2 exceeds the speed corresponding to the angular velocity of the output shaft of the drive motor. Then, since the drive motor drives the gear ring to rotate in the positive direction, the piston rod 2 drives the planetary gear 9 to rotate in the opposite direction. At this time, the sun gear 11 will rotate in the opposite direction, and the valve core 5 will move to the right to reduce the valve opening, thereby reducing the pressure difference on both sides of the push block 21. The piston rod 2 will decelerate to the left until the movement speed of the piston rod 2 reaches the speed corresponding to the angular velocity of the output shaft of the drive motor. At this time, the rotation of the planetary gear 9 and the external gear ring 8 cancel each other out, the valve core 5 stops moving, the valve core 5 remains open, and the piston rod 2 moves forward to the left at a lower speed.

[0032] It is understandable that the movement position control of piston rod 2 can be achieved by adjusting the output power of the drive motor. As piston rod 2 moves, the moving screw 3, planetary reduction assembly and valve core screw 6 can automatically control piston rod 2 to accelerate, decelerate, move at a constant speed or remain stationary through mechanical feedback.

[0033] Furthermore, when piston rod 2 needs to retract, it is only necessary to control the output end of the drive motor to rotate in the opposite direction. The specific principle and transmission process can be referred to the forward movement of piston rod 2, and will not be elaborated here.

[0034] Furthermore, the mechanical feedback type digital cylinder (CN200410069392.3) in related technologies consists of a stepper motor, a two-stage helical pair, a three-position four-way valve, and a hydraulic cylinder. The piston rod 2 of the stepper motor and the hydraulic cylinder simultaneously controls the working position of the three-position four-way valve through the two-stage helical pair, thereby achieving position control of the piston rod 2. However, during the operation of the digital cylinder, the valve core 5 of the three-position four-way valve will both translate and rotate. Moreover, when the cylinder moves at a constant speed, the valve core 5 rotates at high speed, causing rapid wear of the seals on the valve core 5 and a short lifespan. In contrast, when the valve core screw 6 of this application drives the valve core 5 to move, the valve core 5 only translates and does not rotate. Furthermore, when the piston rod 2 moves at a constant speed, the valve core 5 remains stationary, reducing the wear of the valve core 5 seals.

[0035] Furthermore, to ensure the sealing of valve core 5, the movement of valve core 5 needs to have a dead zone (i.e., the valve port only opens when the displacement of valve core 5 exceeds the dead zone value). Also, since the ratio of piston rod 2 to valve core 5 displacement during mechanical feedback is equal to the inverse ratio of the lead screw thread pitch and the lead screw thread pitch of valve core 5, mechanical feedback also has a dead zone. In related technologies, the mechanical feedback dead zone value of a digital cylinder is calculated as valve core 5 dead zone value × lead screw thread pitch ÷ valve core 5 thread pitch. Because the thread pitch is limited by friction self-locking and the ball screw structure, the sealing of valve core 5 and the accuracy of mechanical feedback interfere with each other. In contrast, this application uses a planetary reduction assembly, making the mechanical feedback dead zone value equal to valve core 5 dead zone value × lead screw thread pitch ÷ valve core 5 thread pitch ÷ the transmission ratio between the planetary carrier and the sun gear 11, thus reducing the mechanical feedback dead zone value and improving the accuracy of mechanical feedback.

[0036] In this embodiment of the mechanical feedback digital cylinder, a planetary reduction gear assembly is used as the main body of the mechanical feedback structure. The planetary support 10 is sleeved on the movable lead screw 3, which is threadedly engaged with the piston rod 2. The sun gear 11 is sleeved on the valve core lead screw 6, which is threadedly engaged with the valve core 5. The drive component 16 can drive the sun gear 11 to rotate via the external gear ring 8, thereby driving the valve core lead screw 6 to rotate. The valve core lead screw 6 can drive the valve core 5 to open linearly to control the pressure changes on both sides of the piston rod 2, thus controlling the movement of the piston rod 2. Furthermore, the movement of the piston rod 2 can drive the movable lead screw 3 to rotate, thereby driving the planetary support 10 to reverse direction. The reverse rotation, in conjunction with the drive component 16, provides feedback to the external gear ring 8, which in turn controls the valve core screw 6 to move the valve core 5, thus achieving a mechanical feedback control process. Furthermore, compared to existing technologies, this application utilizes the valve core screw 6 in conjunction with the limiting structure within the valve body 4 to drive the valve core 5 to move only linearly without rotation via screw transmission. When the piston rod 2 moves at a constant speed, the valve core 5 remains stationary, reducing wear on the valve core 5 seals and improving the lifespan of the digital cylinder. Additionally, this application uses a planetary reduction gear assembly as the main body of the mechanical feedback, reducing the dead zone value of the mechanical feedback and improving its accuracy.

[0037] Furthermore, such as Figure 1 and Figure 2 As shown, the mechanical feedback digital cylinder of this application also includes a threaded sleeve 12. The threaded sleeve 12 includes a cylindrical body with internal threads and an annular edge surrounding the outer periphery of the cylindrical body. The cylindrical body fits inside the piston rod 2 and is sleeved on the movable lead screw 3. The annular edge is attached to the side of the piston rod 2 facing the valve core 5 assembly and is connected to the piston rod 2 by screws. Thus, the movable lead screw 3 and the piston rod 2 can achieve lead screw transmission through the threaded sleeve 12.

[0038] Preferably, such as Figure 1 and Figure 2As shown, the cylinder body 1 has a first receiving groove on its outer side facing the valve core 5 assembly. The protruding end of the moving lead screw 3 passes through the cylinder body 1 and extends into the first receiving groove. The planetary support 10 has a sleeve portion that fits into the first receiving groove, and the sleeve portion is sleeved on the protruding end of the moving lead screw 3. Thus, the planetary support 10 and the moving lead screw 3 are assembled in the first receiving groove, resulting in a compact overall structure for the digital cylinder.

[0039] Furthermore, such as Figure 1 and Figure 2 As shown, the inner side of the cylinder body 1 is provided with a second receiving groove opposite to the first receiving groove. The moving screw 3 passes through the second receiving groove, and the second receiving groove is provided with a first bearing 13 supporting the moving screw 3, and the first receiving groove is provided with a second bearing 14 supporting the sleeve portion.

[0040] Optionally, such as Figure 1 and Figure 2 As shown, the movable lead screw 3 has a limiting protrusion 31, which is located on the side of the first bearing 13 away from the second bearing 14. The first bearing 13 can abut against the limiting protrusion 31. Thus, the abutment of the first bearing 13 and the limiting protrusion 31 can prevent the movable lead screw 3 from applying pressure toward the planetary support 10, ensuring the stability of the connection between the planetary support 10 and the movable lead screw 3.

[0041] In some embodiments, such as Figure 1 and Figure 2 As shown, the limiting structure is an end cap 7, which is mounted on the valve body 4 and faces the end of the valve core 5 away from the valve core screw 6. The side of the end cap 7 facing the valve core 5 has a limiting groove of a certain length in the direction of valve core 5's movement. The end of the valve core 5 facing the end cap 7 fits into the limiting groove. It can be understood that by setting a limiting groove on the end cap 7 and utilizing the fit between the limiting groove and the valve core 5 to circumferentially limit the valve core 5, there is no need to set a limiting structure inside the valve body 4. The design is simple, and it facilitates disassembly and maintenance when wear and failure occur at the limiting fit.

[0042] Preferably, the inner wall surface of the limiting groove includes two opposing planes, and the outer peripheral surface of the end of the valve core 5 facing the end cover 7 is in contact with both planes. It can be understood that the two opposing planes can meet the circumferential limiting requirements of the valve core 5, and the limiting surface is small, resulting in less interference with the translational movement of the valve core 5.

[0043] Optionally, the inner wall of the limiting groove is not limited to including two opposing planes. For example, the inner wall of the limiting groove can be designed as a regular polygon or other irregular surface, as long as it can satisfy the circumferential limiting of the valve core 5.

[0044] Alternatively, the limiting fit is not limited to providing a limiting groove on the end cover 7 as described above. For example, a limiting protrusion can be provided in the valve body 4, and a sliding groove extending along the length direction and engaging with the limiting protrusion can be provided on the valve core 5.

[0045] Optionally, valve core 5 is a three-position four-way valve. Optionally, the three-position four-way valve is a pilot-operated three-position four-way valve.

[0046] Optionally, a third bearing 15 is provided inside the valve body 4, which is used to support the valve core screw 6.

[0047] The hydraulic control system of this invention includes the mechanical feedback digital cylinder described in the above embodiment.

[0048] The hydraulic control system of this invention, by adopting the above-mentioned mechanical feedback digital cylinder, has high control accuracy, low wear of valve core 5, long service life, and high system reliability.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] It should be understood that the application of this invention is not limited to the detailed structure and arrangement of the components presented in this specification. The invention can have other embodiments and can be implemented and performed in various ways. The foregoing variations and modifications fall within the scope of this invention. It should be understood that the invention as described and defined in this specification extends to all alternative combinations of two or more individual features mentioned or apparent in the text and / or drawings. All these different combinations constitute multiple alternative aspects of the invention. The embodiments described in this specification illustrate the best known mode for carrying out the invention and will enable those skilled in the art to utilize the invention.

Claims

1. A mechanical feedback digital cylinder, characterized in that, include: The cylinder body, piston rod, and movable lead screw are provided. The piston rod is movably inserted into the cavity of the cylinder body, and the tail end of the piston rod is provided with a push block that is in sealing contact with the inner wall of the cavity. The movable lead screw is inserted into the cylinder body and one end of it is fitted into the piston rod and threadedly engaged with the piston rod. A valve core assembly includes a valve body, a valve core, and a valve core screw. The valve body is connected to the outside of the cylinder body. The valve body has a liquid supply port communicating with a cavity on one side of the push block and a liquid return port communicating with a cavity on the other side of the push block. The valve core is movably disposed in the valve body to control the synchronous opening and closing of the liquid supply port and the liquid return port. The valve core screw passes through the valve core and is threadedly engaged with the valve core. The valve body is provided with a limiting structure that can prevent the valve core from rotating. A planetary reduction gear assembly and a drive component are provided. The planetary reduction gear assembly includes an external gear ring, a sun gear, planet gears, and a planetary support for supporting the planet gears. The planetary support is sleeved on the movable lead screw, the sun gear is sleeved on the valve core lead screw, the planet gears are engaged between the external gear ring and the sun gear, and the drive component meshes with the outer side of the external gear ring.

2. The mechanical feedback digital cylinder according to claim 1, characterized in that, It also includes a threaded sleeve, which includes a cylindrical body with internal threads and an annular edge surrounding the outer periphery of the cylindrical body. The cylindrical body fits inside the piston rod and is sleeved on the movable lead screw. The annular edge is attached to the side of the piston rod facing the valve core assembly and is connected to the piston rod by screws.

3. The mechanical feedback digital cylinder according to claim 1, characterized in that, The cylinder body has a first receiving groove on the outer side facing the valve core assembly. The protruding end of the moving lead screw passes through the cylinder body and extends into the first receiving groove. The planetary support has a sleeve portion that fits into the first receiving groove. The sleeve portion is sleeved on the protruding end of the moving lead screw.

4. The mechanical feedback digital cylinder according to claim 3, characterized in that, The inner side of the cylinder is provided with a second receiving groove opposite to the first receiving groove. The moving lead screw passes through the second receiving groove, and a first bearing supporting the moving lead screw is provided in the second receiving groove. A second bearing supporting the sleeve portion is provided in the first receiving groove.

5. The mechanical feedback digital cylinder according to claim 4, characterized in that, The movable lead screw has a limiting protrusion ring, which is located on the side of the first bearing away from the second bearing, and the first bearing can abut against the limiting protrusion ring.

6. The mechanical feedback digital cylinder according to claim 1, characterized in that, The limiting structure is an end cap, which is installed on the valve body and is opposite to the end of the valve core away from the valve core screw. The side of the end cap facing the valve core is provided with a limiting groove of a certain length in the moving direction of the valve core, and the end of the valve core facing the end cap is fitted into the limiting groove.

7. The mechanical feedback digital cylinder according to claim 6, characterized in that, The inner wall of the limiting groove includes two opposing planes, and the outer peripheral surface of the end of the valve core facing the end cap is in contact with both planes.

8. The mechanical feedback digital cylinder according to claim 1, characterized in that, The valve core assembly is a three-position four-way valve.

9. The mechanical feedback digital cylinder according to claim 1, characterized in that, The valve body is provided with a third bearing, which is used to support the valve core screw.

10. A hydraulic control system, characterized in that, Including the mechanical feedback digital cylinder as described in any one of claims 1-9.

Images