A rotary direct drive servo spool valve

Abstract

The application relates to a rotary direct-drive type servo spool, belonging to the field of hydraulic components, which comprises a valve body, a valve core, a transmission mechanism and a servo driving mechanism, a plurality of hydraulic oil ports are arranged on the valve body, a plurality of valve cavities respectively connected with the hydraulic oil ports are arranged in the valve body, the valve core is arranged in the valve body and can slide relative to the valve body to switch the connection relationship among the valve cavities, an axially extending valve core hole is arranged in the valve core, the transmission mechanism extends into the valve core hole from one end of the valve core and is connected with the end area of the other end of the valve core, an eccentric mechanism is arranged on the output shaft of the servo driving mechanism, and the transmission mechanism is connected with the eccentric mechanism to drive the valve core to slide through the transmission mechanism, so that the control precision of the servo valve can be improved.

Description

Technical Field

[0001] This application relates to the field of hydraulic components, specifically to a rotary direct-drive servo spool valve. Background Technology

[0002] Hydraulic valves are hydraulic components used in hydraulic transmission to control the pressure, flow rate, and direction of liquid. They can operate in manual, hydraulically controlled, or electrically controlled modes and are indispensable components in the field of hydraulic transmission. Electro-hydraulic servo valves, also known as servo valves, are hydraulic valves that can control the output modulated flow rate and pressure through closed-loop control under the control of analog electrical signals. They have advantages such as fast dynamic response, high control accuracy, and long service life, and are widely used in high-precision mechatronic systems, aerospace, shipbuilding, metallurgy, chemical industries, and electro-hydraulic servo control systems of large-scale testing equipment.

[0003] Based on the different ways the valve core moves within the valve body, servo valves can be divided into sliding servo valves and rotary servo valves. Sliding servo valves control the sliding of the valve core within the valve body, allowing the connecting oil grooves on the valve core to form varying degrees of connection with different valve chambers within the valve body. This controls the pressure, flow rate, and direction of the hydraulic oil in the valve chambers. The valve core has a large range of motion, making it easier to precisely control its position. Based on the different methods of valve core actuation, servo valves can be divided into pilot-operated servo valves and direct-drive servo valves. Direct-drive servo valves use a servo drive device to directly drive the valve core, offering advantages such as simpler valve structure, higher control reliability, and longer service life.

[0004] Existing sliding direct-drive servo valves typically use a linear force motor to drive the valve core, relying on a displacement sensor for position feedback, resulting in poor control accuracy. Furthermore, the linear force motor is usually located at the end of the valve core, leading to a longer servo valve length and hindering miniaturization. Some sliding servo valves use a rotary servo motor with an eccentric structure to drive the valve core within the valve body. However, this eccentric structure easily creates lateral stress on the valve core, affecting the smoothness of its sliding within the valve body, thus impacting the control accuracy of the servo valve and potentially causing jamming during valve core movement. Summary of the Invention

[0005] To improve the control accuracy of servo valves, this application provides a rotary direct-drive servo spool valve.

[0006] The rotary direct-drive servo slide valve provided in this application adopts the following technical solution: A rotary direct-drive servo spool valve includes a valve body, a valve core, a transmission mechanism, and a servo drive mechanism. The valve body has multiple hydraulic ports and multiple valve chambers connected to the hydraulic ports. The valve core is disposed in the valve body and can slide relative to the valve body to switch the connection relationship between the valve chambers. The valve core has an axially extending valve core hole. The transmission mechanism extends from one end of the valve core into the valve core hole and is connected to the end region of the other end of the valve core. An eccentric mechanism is disposed on the output shaft of the servo drive mechanism and is connected to the transmission mechanism through the eccentric mechanism to drive the valve core to slide.

[0007] By adopting the above technical solution, and by using the end area of ​​the transmission mechanism connected from the valve core hole to the other end of the valve core, the distance between the connection point of the transmission mechanism and the valve core and the servo drive mechanism can be extended. This allows the elastic deformation of the transmission mechanism itself to reduce the lateral force acting on the valve core due to the swaying of the eccentric mechanism. While converting the rotational motion of the servo drive mechanism into the linear motion of the valve core, it ensures the smooth movement of the valve core in the valve body and improves the control accuracy of the servo valve.

[0008] In one specific implementation, a transmission connecting plate is provided in the end region of the valve core hole away from the servo drive mechanism. The periphery of the transmission connecting plate is integrally connected to the wall of the valve core hole, and the transmission mechanism is integrally connected to the middle of the transmission connecting plate.

[0009] By adopting the above technical solution, and utilizing the integrated connection of the transmission mechanism in the middle of the transmission connecting plate, the driving force of the transmission mechanism on the valve core can be made to act on the central axis of the valve core, thereby improving the uniformity of force on different positions around the valve core under the traction of the transmission mechanism and preventing jamming during the sliding process of the valve core. The integrated connection between the transmission mechanism, the transmission connecting plate and the valve core can improve the connection accuracy and stability between the transmission mechanism, the transmission connecting plate and the valve core, which is conducive to improving the control accuracy of the valve core position.

[0010] In one specific implementation, the transmission mechanism includes a transmission rod, the end of which is connected to the transmission connecting plate. The cross-section of the transmission rod is a rectangle with a height parallel to the output shaft of the servo drive mechanism, and the length of the upper and lower base sides of the rectangle is less than the height of the rectangle. Deformation buffer holes are provided on both sides of the transmission rod in the height direction at the connection between the transmission connecting plate and the transmission rod.

[0011] By adopting the above technical solution, using a transmission rod with a cross-section whose height is greater than the length of its upper and lower sides, it is possible to provide a sufficiently large pushing force to the valve core while improving the lateral deformation capacity of the transmission rod, reducing the lateral stress formed on the valve core by the eccentric mechanism's circumferential motion, and ensuring the smooth movement of the valve core in the valve body. By using the deformation buffer holes set on the upper and lower sides of the connection between the transmission connecting plate and the transmission rod, the deformation at the connection between the transmission connecting plate and the transmission rod can be increased, reducing the transmission of deformation stress at the connection to the periphery of the transmission connecting plate, and further reducing the lateral stress on the valve core.

[0012] In one specific implementation, the transmission mechanism includes a transmission sleeve, the eccentric mechanism includes an eccentric rod, the eccentric rod is connected to the output shaft of the servo drive mechanism and is eccentrically disposed with respect to the output shaft of the servo drive mechanism, and the transmission sleeve is sleeved on the eccentric rod and rotatably connected to the eccentric rod.

[0013] By adopting the above technical solution, and utilizing the rotational connection between the transmission sleeve and the eccentric rod, the eccentric rotational motion of the eccentric rod can be used to drive the valve core to make linear motion. Thus, by controlling the rotation angle of the servo drive mechanism, the moving position of the valve core can be precisely controlled, thereby improving the control accuracy of the valve core position.

[0014] In one specific implementation scheme, the eccentric mechanism further includes an eccentric connecting wheel, an eccentric connecting rod, and an eccentric mechanism rotating shaft. The eccentric connecting wheel is fixed on the output shaft of the servo drive mechanism, and the eccentric rod is fixed at the periphery of the eccentric connecting wheel. One end of the eccentric connecting rod is connected to the eccentric rod, and the other end is connected to the eccentric mechanism rotating shaft. The eccentric mechanism rotating shaft is coaxially arranged with the output shaft of the servo drive mechanism and is rotatably connected to the valve body.

[0015] By adopting the above technical solution, the eccentric mechanism, formed by connecting the eccentric connecting wheel, eccentric rod, eccentric connecting rod, and eccentric mechanism rotating shaft, can reduce the weight of the eccentric mechanism and decrease the vibration generated by its rotation. The rotational connection between the eccentric mechanism rotating shaft and the valve body reduces the deformation of the eccentric rod during rotation, improves its positional stability under stress, and thus enhances the positional accuracy of the valve core.

[0016] In one specific implementation scheme, the rotary direct-drive servo spool valve of this application further includes an end cap and an elastic centering device. The end cap is fixed on the valve body, and the elastic centering device is disposed on the inner side of the end cap and connected to the valve core so as to generate a driving force to push the valve core back to the center position.

[0017] By adopting the above technical solution and utilizing the elastic centering device connected to the valve core, an elastic force can be generated towards the center position when the valve core leaves the center position. This allows the valve core to be automatically pulled back to the center position when the servo valve loses power, ensuring the safety of the hydraulic device.

[0018] In one specific implementation, the elastic centering device includes a first spring seat, a spring seat connector, a centering spring, and a second spring seat. The spring seat connector passes through the first spring seat and the second spring seat and is fixed to the end of the valve core, and is slidably connected to the first spring seat and the second spring seat. The centering spring is sleeved on the spring seat connector and is disposed between the first spring seat and the second spring seat. The first spring seat abuts against the end cap, and the second spring seat abuts against the valve body.

[0019] By adopting the above technical solution, and using the spring seat connector to pass through the first spring seat, the centering spring, and the second spring seat in sequence to connect with the valve core, the first spring seat or the second spring seat can be driven to compress the centering spring when the valve core moves to both sides. This creates a simple structure that forms a spring force for the valve core to return to the center position in both directions, thus realizing the automatic return to the center position of the servo valve when it is de-energized.

[0020] In one specific implementation scheme, the servo drive mechanism is fixed to the side of the valve body, and the output shaft of the servo drive mechanism is perpendicular to the valve core. The servo drive mechanism includes a motor rotor, a motor stator, a motor housing, and a motor end cover. The motor housing is fixed to the valve body, the motor stator is fixed inside the motor housing, the motor rotor is disposed inside the motor stator, and the motor end cover is fixed to the end of the motor housing away from the valve body. One end of the motor rotor is rotatably connected to the motor housing, and the other end is rotatably connected to the motor end cover through an end cover bearing. A wave washer is provided between the end of the end cover bearing and the motor end cover.

[0021] By adopting the above technical solution, and utilizing the perpendicular arrangement of the output shaft of the servo drive mechanism to the valve core, the transmission rod can be made to move only in the horizontal plane under the drive of the eccentric mechanism. This improves the uniformity of force distribution at the other end of the transmission rod and helps to improve the smoothness of the valve core movement. The wave-shaped washer located between the end of the end cap bearing and the motor end cap applies axial force to the motor rotor, reducing axial movement during rotor rotation, improving the stability of the servo drive mechanism's rotation, and ensuring the positional accuracy of the valve core.

[0022] In one specific implementation, an inductive magnetic braid is provided at one end of the motor rotor adjacent to the motor end cover, a sealing cover is provided on the outside of the motor end cover, the sealing cover is sealed to the motor end cover, the inductive magnetic braid is located inside the sealing cover, a PCBA is provided on the outside of the sealing cover, a magnetic braid sensing element is provided on the PCBA, and the magnetic braid sensing element is correspondingly provided with the inductive magnetic braid.

[0023] By adopting the above technical solution, and utilizing the induction magnetic encoder and the corresponding magnetic encoder sensing element located at the end of the motor rotor, the rotation angle of the motor rotor can be detected in real time. This enables closed-loop control of the motor rotor's rotation angle, improving the control accuracy. Furthermore, by using a sealing cover positioned between the induction magnetic encoder and the magnetic encoder sensing element, and sealed to the motor end cover, the installation space of the moving parts of the servo drive mechanism and the installation space of the control elements can be isolated while the rotation angle of the motor rotor is monitored in real time. This prevents oil seeping into the installation space of the moving parts from contaminating the control elements.

[0024] In one specific implementation scheme, the rotary direct-drive servo spool valve of this application further includes a valve sleeve disposed in the valve body. The valve sleeve is provided with a plurality of valve sleeve holes connected to the valve cavity. The valve core is slidably disposed in the valve sleeve. The valve sleeve and the valve body are sealed with a gap, and the valve core and the valve sleeve are fitted with a gap.

[0025] By adopting the above technical solution, the valve sleeve installed in the valve body improves the accuracy of the valve port connecting the valve cavity and the connecting oil groove on the valve core, thereby improving the control accuracy of the servo valve flow rate. The gap sealing between the valve sleeve and the valve body, as well as the gap fit between the valve core and the valve sleeve, further improves the smoothness of the valve core sliding within the valve sleeve, preventing the valve core from jamming in the valve sleeve under lateral stress.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By connecting the eccentric mechanism set on the output shaft of the servo drive mechanism with the transmission mechanism, the rotational motion of the servo drive mechanism can be converted into linear motion at the other end of the transmission mechanism. This allows for more precise control of the valve core sliding position using the servo drive mechanism with higher control accuracy, thereby improving the control accuracy of the servo valve.

[0027] 2. By using the valve core hole inside the valve core, the transmission mechanism can be connected to the end of the valve core away from the servo drive mechanism through the valve core hole, thereby increasing the length of the transmission mechanism and increasing the elastic deformation of the transmission mechanism. When one end of the transmission mechanism rotates with the eccentric mechanism at the same amplitude, the lateral force at the other end of the transmission mechanism is reduced, thereby reducing the lateral stress on the valve core and ensuring the smoothness of the valve core movement in the valve body.

[0028] 3. By using a transmission connecting plate set inside the valve core hole and a transmission rod integrally connected to the middle of the transmission connecting plate, the driving force of the transmission rod acting on the valve core can be directed to the axial position of the valve core, which helps to improve the balance of the driving force on the valve core. Furthermore, by using deformation buffer holes set on both sides of the transmission rod in the height direction, the deformation at the connection between the transmission connecting plate and the transmission rod is increased, reducing the transmission of lateral force from the end of the transmission rod to the valve core, improving the stability of the valve core position, and reducing the lateral stress on the valve core.

[0029] 4. The centering device, consisting of a first spring seat, a spring seat connector, a centering spring, and a second spring seat, can generate a bidirectional centering force on the valve core through a simple structure, ensuring that the servo valve can return to the neutral position from different valve positions when it loses power, thus ensuring the safety of the hydraulic system. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of one embodiment of this application.

[0031] Figure 2 This is a schematic diagram of the internal structure of one embodiment of this application.

[0032] Figure 3 This is a schematic diagram of the case after the outer shell is hidden in one embodiment of this application.

[0033] Figure 4 for Figure 3 Cross-sectional view with AA orientation.

[0034] Figure 5 for Figure 4 Central BB orientation sectional view.

[0035] Figure 6 This is a schematic diagram of the valve body in one embodiment of this application.

[0036] Figure 7 This is a schematic diagram of an integrated structure of the valve core and transmission mechanism in one embodiment of this application.

[0037] Figure 8 This is an exploded view of the centering mechanism components in one embodiment of this application.

[0038] Figure 9This is a schematic diagram of a servo drive mechanism in one embodiment of this application.

[0039] Figure 10 This is a schematic diagram of a valve sleeve in one embodiment of this application.

[0040] Figure 11 This is a schematic diagram of the valve core in the center position in one embodiment of this application.

[0041] Figure 12 This is a schematic diagram of the valve core in the left position state in one embodiment of this application.

[0042] Figure 13 This is a schematic diagram of the valve core in the left position in one embodiment of this application.

[0043] Figure 14 This is a schematic diagram of the valve core in the right-hand position in one embodiment of this application.

[0044] Figure 15 A schematic diagram of the valve core on the right side in one embodiment of this application.

[0045] Explanation of reference numerals in the attached drawings: 1. Valve body; 101. P port; 102. T port; 103. A port; 104. B port; 11. Main bore of valve body; 12. P chamber; 13. A chamber; 14. B chamber; 15. First T chamber; 16. Second T chamber; 17. Drive mechanism mounting interface; 18. Plug; 2. Valve core; 21. Valve core hole; 22. Transmission connecting plate; 221. Deformation buffer hole; 23. First connecting slot; 24. Second connecting slot; 25. Third connecting slot; 26. Spring seat mounting slot; 27. Spring seat slide column; 3. Transmission mechanism; 31. Transmission rod; 32. Transmission sleeve; 4. Servo drive mechanism; 41. Eccentric mechanism; 411. Eccentric rod; 412. Eccentric connecting wheel; 413. Eccentric connecting rod; 414. Eccentric mechanism rotating shaft; 42. Motor rotor; 43. Motor stator; 44. Motor housing; 45. Motor end cover; 51. End cap bearing; 452. Waveform washer; 46. Induction magnetic encoder; 47. Sealing cover; 48. PCBA; 5. End cap; 6. Centering device; 61. First spring seat; 62. Spring seat connector; 63. Centering spring; 64. Second spring seat; 7. Valve sleeve; 71. Valve sleeve P port; 72. Valve sleeve A port; 73. Valve sleeve B port; 74. Valve sleeve first T port; 75. Valve sleeve second T port; 76. Valve sleeve retaining edge; 8. Cover; 81. Electrical interface. Detailed Implementation

[0046] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0047] In this application, unless otherwise stated, the orientation or positional relationship indicated by directional terms such as "left" and "right" is based on the orientation or positional relationship shown in the accompanying drawings of this application, and the description of the orientation and positional relationship of each component in this application is the same.

[0048] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] In this specification, the terms "first," "second," and "third" 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. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of the stated features.

[0050] One embodiment of the rotary direct-drive servo slide valve of this application is as follows: Figure 1 Zhihe Figure 5 As shown, the system includes a valve body 1, a valve core 2, a transmission mechanism 3, and a servo drive mechanism 4. The valve body 1 is 3D printed, resulting in a small size and light weight. The flow path within the valve body 1 is smooth, with low pressure loss and high flow capacity. Multiple hydraulic ports are located at the bottom of the valve body 1, such as P port 101, T port 102, A port 103, and B port 104, for connecting to external hydraulic circuits. Inside the valve body 1, multiple valve chambers are connected to these hydraulic ports, such as P chamber 12, A chamber 13, B chamber 14, a first T chamber 15, and a second T chamber 16. P chamber 12 is connected to P port 101, A chamber 13 is connected to A port 103, B chamber 14 is connected to B port 104, and both the first T chamber 15 and the second T chamber 16 are connected to T port 102. A valve body main hole 11 is also provided at the center of the valve body 1. The first T cavity 15, B cavity 14, P cavity 12, A cavity 13 and the second T cavity 16 are arranged sequentially in the length direction of the valve body main hole 11 and are all connected to the valve body main hole 11.

[0051] The valve core 2 is disposed in the valve body 1, typically in the main bore 11 of the valve body, and can slide along the length of the main bore 11. Multiple connecting grooves are provided on the outer circumferential surface of the valve core 2, such as a first connecting groove 23, a second connecting groove 24, and a third connecting groove 25 at different axial positions of the valve core 2. When the valve core 2 moves to different positions in the main bore 11 of the valve body, the P chamber 12, A chamber 13, B chamber 14, first T chamber 15, and second T chamber 16 can form different connection states with the first connecting groove 23, second connecting groove 24, and third connecting groove 25, thereby changing the on / off state, flow direction, and flow rate of the hydraulic oil at port A 103 and port B 104.

[0052] like Figure 6 As shown, a drive mechanism mounting interface 17 is provided on the side of the valve body 1, next to the main bore 11 of the valve body. The drive mechanism mounting interface 17 is located at one end of the main bore 11 of the valve body along its length. The servo drive mechanism 4 is fixed to the valve body 1 through the drive mechanism mounting interface 17, and the output shaft of the servo drive mechanism 4 passes through the drive mechanism mounting interface 17 and enters the main bore 11 of the valve body. An eccentric mechanism 41 is provided on the output shaft of the servo drive mechanism 4. The eccentric mechanism 41 is eccentrically positioned to the output shaft of the servo drive mechanism 4. When the output shaft of the servo drive mechanism 4 rotates, it can drive the eccentric mechanism 41 to perform eccentric circular motion.

[0053] The transmission mechanism 3 can use various devices capable of converting circular motion into linear motion, such as crankshaft devices, connecting rod devices, etc. The transmission mechanism 3 is connected between the eccentric mechanism 41 and the valve core 2, and can convert the eccentric motion of the eccentric mechanism 41 into the sliding motion of the valve core 2 within the valve body 1. For example... Figure 2 and Figure 4 As shown, an axially extending valve core hole 21 is provided inside the valve core 2. The transmission mechanism 3 extends into the valve core hole 21 from one end of the valve core 2 adjacent to the servo drive mechanism 4, and connects to the end region of the valve core 2 away from the servo drive mechanism 4. Since the transmission mechanism 3 connects to the valve core 2 through the valve core hole 21, the connection point is closer to the center of the valve core 2, which makes the movement of the valve core 2 under the drive of the transmission mechanism 3 more stable. The other end of the transmission mechanism 3 is rotatably connected to the eccentric mechanism 41 and can move in a circular motion with the eccentric mechanism 41, forming a driving force to drive the valve core 2 to slide. The specific eccentricity between the eccentric mechanism 41 and the output shaft of the servo drive mechanism 4 is determined according to the required sliding stroke of the valve core 2.

[0054] The transmission mechanism 3 is connected from the eccentric mechanism 41 to the end region of the valve core 2 away from the servo drive mechanism 4, so that the transmission mechanism 3 has a longer length, which can reduce the tangential force formed by the circumferential motion at one end of the transmission mechanism 3 at the other end of the transmission mechanism 3, thereby reducing the tangential stress borne by the valve core 2 and improving the smoothness of the valve core 2 sliding under the drive of the transmission mechanism 3.

[0055] In some embodiments of the rotary direct-drive servo spool valve of this application, such as Figure 2 , Figure 4 and Figure 5 As shown, a transmission connecting plate 22 is provided in the end region of the valve core hole 21 away from the servo drive mechanism 4. The periphery of the transmission connecting plate 22 is integrally connected to the wall of the valve core hole 21. The end of the transmission mechanism 3 is integrally connected to the middle of the transmission connecting plate 22, which is the central axis position of the valve core 2.

[0056] Specifically, the valve core 2 and the transmission mechanism 3 are an integrated structure formed by 3D printing. The transmission mechanism 3 is connected to the middle of the transmission connecting plate 22, and the driving force of the transmission mechanism 3 acting on the transmission connecting plate 22 is directed to the center of the valve core 2. The periphery of the transmission connecting plate 22 is connected to the wall of the valve core hole 21, which can evenly apply the driving force of the transmission mechanism 3 to the periphery of the valve core 2, thus improving the stability of the valve core 2 under the drive of the transmission mechanism 3. The transmission mechanism 3 is usually made of a material with a large elastic deformation, and the region that runs through the length of the valve core 2 is connected to the eccentric mechanism 41 at a distance from the valve core 2, giving the transmission mechanism 3 a longer deformation length. This helps to reduce the tangential force exerted by the transmission mechanism 3 on the valve core 2, reduce the tangential stress borne by the valve core 2, and improve the smoothness of the valve core 2's sliding.

[0057] In a preferred embodiment of the rotary direct-drive servo slide valve of this application, such as Figure 2 , Figure 4 and Figure 5 As shown, the transmission mechanism 3 includes a transmission rod 31 and a transmission sleeve 32. The transmission sleeve 32 is rotatably connected to the eccentric mechanism 41. The transmission rod 31 is connected between the transmission sleeve 32 and the transmission connecting plate 22. The end of the transmission rod 31 is integrally connected to the middle of the transmission connecting plate 22.

[0058] The transmission rod 31 is a rectangular strip with a rectangular cross-section. The height of this rectangular cross-section is parallel to the output shaft of the servo drive mechanism 4, and the lengths of the top and bottom edges of the rectangular cross-section are significantly shorter than its height. This means that when the transmission rod 31 moves in a circular motion with the eccentric mechanism 41, its thickness in the direction perpendicular to the valve core 2 is smaller. This helps to increase the deformation of the transmission rod 31 during its swing and reduce the tangential force exerted by the transmission rod 31 on the transmission connecting plate 22. Furthermore, the higher height of the transmission rod 31 helps to ensure the axial driving force exerted by the transmission rod 31 on the transmission connecting plate 22.

[0059] At the connection point between the transmission connecting plate 22 and the transmission rod 31, a deformation buffer hole 221 is provided on each side of the transmission rod 31 in the height direction. The deformation buffer hole 221 can increase the deformation of the connection part between the transmission connecting plate 22 and the transmission rod 31, reduce the transmission of tangential stress to the surrounding area, and thus further reduce the tangential stress on the valve core 2.

[0060] In some embodiments of the rotary direct-drive servo spool valve of this application, such as Figure 7 and Figure 8 As shown, the transmission mechanism 3 includes a transmission rod 31 and a transmission sleeve 32; the eccentric mechanism 41 includes an eccentric rod 411. The eccentric rod 411 can be connected to the output shaft of the servo drive mechanism 4 in various possible connection methods, keeping the eccentric rod 411 parallel to the output shaft of the servo drive mechanism 4, and eccentrically set to the output shaft of the servo drive mechanism 4.

[0061] The transmission sleeve 32 is fitted onto the eccentric rod 411 and is usually mounted on the eccentric rod 411 via a needle roller bearing so that it can rotate on the eccentric rod 411. When the servo drive mechanism 4 rotates, the transmission sleeve 32 can move in a circular motion with the eccentric rod 411, and pull the valve core 2 to slide linearly in the valve body 1 via the transmission rod 31.

[0062] In a preferred embodiment of the rotary direct-drive servo slide valve of this application, such as Figure 7 As shown, the eccentric mechanism 41 includes an eccentric rod 411, an eccentric connecting wheel 412, an eccentric connecting rod 413, and an eccentric mechanism rotation shaft 414. The eccentric connecting wheel 412 is a round wheel with a diameter slightly larger than the eccentricity requirement of the eccentric rod 411, and the eccentric connecting wheel 412 is coaxially fixed on the output shaft of the servo drive mechanism 4.

[0063] The eccentric rod 411 is fixed around the eccentric connecting wheel 412 and can make eccentric circular motion as the eccentric connecting wheel 412 rotates.

[0064] One end of the eccentric connecting rod 413 is connected to the eccentric rod 411, and the other end is inclined toward the rotation axis of the eccentric connecting wheel 412 and connected to the rotation axis 414 of the eccentric mechanism.

[0065] The eccentric mechanism rotating shaft 414 is coaxially arranged with the output shaft of the servo drive mechanism 4. When the servo drive mechanism 4 is installed on the drive mechanism mounting interface 17 of the valve body 1, the eccentric rod 411 is located in the middle of the diameter of the main hole 11 of the valve body, and the end of the eccentric mechanism rotating shaft 414 is rotatably connected to the valve body 1 on the opposite side of the main hole 11 of the valve body. Usually, the eccentric mechanism rotating shaft 414 and the valve body 1 are rotatably connected by bearings. While reducing the rotational resistance of the eccentric mechanism rotating shaft 414, the position of the eccentric mechanism rotating shaft 414 is limited, ensuring the accuracy of the eccentric rotation trajectory of the eccentric rod 411, thereby ensuring the positional accuracy of the valve core 2.

[0066] A plug 18 is provided at the opening of the valve body main hole 11 where the eccentric mechanism 41 is located. The plug 18 is threaded to the hole wall at the opening of the valve body main hole 11. When the plug 18 is connected to the opening of the valve body main hole 11, a seal can be formed at the opening of the valve body main hole 11. The plug 18 can be removed to allow the installation or maintenance of the structure inside the valve body main hole 11 through the opening of the valve body main hole 11.

[0067] In some embodiments of the rotary direct-drive servo spool valve of this application, such as Figure 4 , Figure 8 and Figure 9 As shown, an end cap 5 is also provided at one end of the valve body main hole 11 on the valve body 1. An elastic centering device 6 is provided between the valve core 2 and the valve body 1 in the valve body main hole 11 inside the end cap 5.

[0068] The end cap 5 is fixed to the side wall of the valve body 1 on the outside of the valve body main hole 11 by screws, forming a sealed installation space between the end of the valve core 2 and the end cap 5. The elastic centering device 6 is set in the sealed space inside the end cap 5.

[0069] The elastic centering device 6 can use various devices capable of generating bidirectional elastic force on the valve core 2, thus pushing the valve core 2 towards the center position. Under the action of the elastic centering device 6, once the valve core 2 leaves the center position, whether it moves to the left or right valve position, the elastic centering device 6 can generate a pushing force to push the valve core 2 back to the center position. In this way, regardless of the valve position state of the valve core 2, if the servo valve unexpectedly loses power, the valve core 2 can automatically return to the center position under the action of the elastic centering device 6, preventing unexpected operation of the hydraulic equipment containing the rotary direct-drive servo spool valve after power is restored, and ensuring the safety of the hydraulic equipment.

[0070] In a preferred embodiment of the rotary direct-drive servo slide valve of this application, such as Figure 4 , Figure 8 and Figure 9 As shown, the elastic centering device 6 includes a first spring seat 61, a spring seat connector 62, a centering spring 63, and a second spring seat 64. The first spring seat 61 and the second spring seat 64 are generally cylindrical, with an outer flange at one end and an inner flange at the other end. A sliding hole is formed in the middle of the inner flange. The outer flange of the first spring seat 61 faces the end cover 5, and the outer flange of the second spring seat 64 faces the valve core 2. The inner flanges of the first spring seat 61 and the second spring seat 64 are positioned opposite each other.

[0071] A centering spring 63 is disposed between a first spring seat 61 and a second spring seat 64. Both ends of the centering spring 63 are respectively fitted onto the first spring seat 61 and the second spring seat 64, and the ends of the centering spring 63 abut against the inner sides of the outer flanges of the first spring seat 61 and the second spring seat 64. Under the elastic force of the centering spring 63, the outer side of the outer flange of the first spring seat 61 abuts against the end cover 5, and the outer side of the outer flange of the second spring seat 64 abuts against the valve body 1 surrounding the valve body main hole 11, or against the end of the valve sleeve 7 installed in the valve body main hole 11.

[0072] The spring seat connector 62 passes through the sliding hole in the middle of the inner flange of the first spring seat 61 and the second spring seat 64 and is fixed to the end of the valve core 2, such that the inner flange of the first spring seat 61 abuts against the end cap of the spring seat connector 62, and the inner flange of the second spring seat 64 abuts against the valve core 2. A sliding connection is formed between the spring seat connector 62 and both the first spring seat 61 and the second spring seat 64.

[0073] As a specific implementation method, such as Figure 8 As shown, a spring seat mounting groove 26 and a spring seat slide 27 are respectively provided at the end of the valve core 2, with the spring seat slide 27 located at the outer end of the spring seat mounting groove 26. A second spring seat 64 is fitted onto the spring seat slide 27 through a sliding hole in the middle of its inner flange, such that the main body of the second spring seat 64 is located in the spring seat mounting groove 26, and the outer flange of the second spring seat 64 abuts against the side wall of the spring seat mounting groove 26. A first spring seat 61 is fitted onto the spring seat slide 27 through a sliding hole in the middle of its inner flange. A spring seat connector 62 is fixed to the end of the spring seat slide 27 from the inner hole of the first spring seat 61. The diameter of the end cap of the spring seat connector 62 is larger than the diameter of the sliding hole of the first spring seat 61, thus restricting the inner flange of the first spring seat 61 to the spring seat slide 27 through the end cap of the spring seat connector 62. Both the first spring seat 61 and the second spring seat 64 can slide on the spring seat slide 27.

[0074] When the valve core 2 moves to the left, it pushes the second spring seat 64 to move to the left, while the first spring seat 61 remains stationary due to the constraint of the end cover 5. The distance between the second spring seat 64 and the first spring seat 61 shortens, compressing the centering spring 63. The elastic force of the centering spring 63 acts on the valve core 2 through the second spring seat 64, forming a force that pushes the valve core 2 to move to the right, which can push the valve core 2 back to the center position when the servo drive mechanism 4 is de-energized. When the valve core 2 moves to the right, the first spring seat 61 is pulled to the right by the spring seat connector 62 fixed to the end of the valve core 2, while the second spring seat 64 remains stationary due to the constraint of the valve body 1 or the valve sleeve 7 constrained by the valve body 1. The distance between the first spring seat 61 and the second spring seat 64 shortens, compressing the centering spring 63. The elastic force of the centering spring 63 acts on the valve core 2 through the first spring seat 61 and the spring seat connector 62, forming a force that pushes the valve core 2 to move to the left. Similarly, it can push the valve core 2 back to the center position when the servo drive mechanism 4 loses power. In this way, regardless of whether the valve core 2 is in the left or right position when the servo drive mechanism 4 loses power, the valve core 2 can return to the center position under the action of the elastic centering device 6, ensuring the safety of the hydraulic equipment.

[0075] In some embodiments of the rotary direct-drive servo spool valve of this application, such as Figure 2 and Figure 3 As shown, the servo drive mechanism 4 uses a servo motor. The servo drive mechanism 4 is fixed to the side of the valve body 1, specifically to the drive mechanism mounting interface 17 on the side of the valve body 1. The output shaft of the servo drive mechanism 4 is perpendicular to the length direction of the valve core 2.

[0076] The servo drive mechanism 4 includes a motor rotor 42, a motor stator 43, a motor housing 44, and a motor end cover 45. The end of the motor housing 44 is fixed to the valve body 1, such that the central axis of the motor housing 44 intersects the central axis of the valve body main hole 11. The motor stator 43 is fixed to the inner wall of the motor housing 44, and stator coils are provided on the motor stator 43. The motor rotor 42 is rotatably connected to the motor housing 44, and a ring of magnets is evenly distributed around its circumference. The motor rotor 42 is installed inside the rotor hole of the motor stator 43. The motor end cover 45 is fixed to the end of the motor housing 44 away from the valve body 1. A rotor shaft hole is provided in the middle of the motor end cover 45. One end of the motor rotor 42 is rotatably connected to the motor housing 44, and the other end is installed in the rotor shaft hole and rotatably connected to the end cover bearing 451.

[0077] A bearing mounting seat coaxially arranged with the rotor shaft hole is provided on the inner side of the motor end cover 45. An end cover bearing 451 is installed in the bearing mounting seat. The rotation shaft of the motor rotor 42 is installed in the inner ring of the end cover bearing 451, forming a rotational connection between the end cover bearing 451 and the rotor rotor 42. The end cover bearing 451 can improve the positional stability of the motor rotor 42 when it rotates.

[0078] A wave washer 452 is provided between the end of the end cover bearing 451 and the motor end cover 45 at the bottom of the bearing mounting seat. The wave washer 452 can pre-apply a certain axial thrust to the motor rotor 42 to eliminate bearing clearance, improve the positional stability of the motor rotor 42 during rotation, and reduce the rotational noise of the motor rotor 42.

[0079] In a preferred embodiment of the rotary direct-drive servo slide valve of this application, such as Figure 2 As shown, an induction magnetic braid 46 is provided at one end of the motor rotor 42 near the motor end cover 45, and the magnetic properties of the induction magnetic braid 46 at different positions in the circumferential direction change periodically.

[0080] A sealing cover 47 covering the area around the rotor shaft hole is provided on the outside of the motor end cover 45. The induction magnetic braid 46 is disposed on the outside of the motor end cover 45, between the motor end cover 45 and the sealing cover 47. The periphery of the sealing cover 47 is sealed to the motor end cover 45, sealing the induction magnetic braid 46 in the installation space connected to the motor housing 44, thus isolating it from the external space.

[0081] The PCBA (Printed Circuit Board Assembly) 48 is located outside the sealing cover 47. The PCBA 48 is equipped with various control elements for controlling the operation of the servo drive mechanism 4, including a magnetic braiding sensor for detecting the rotational state of the magnetic braiding 46. This magnetic braiding sensor is positioned on the PCBA 48 opposite to the magnetic braiding 46 and can detect the rotation angle of the magnetic braiding 46 from outside the sealing cover 47. The stator coil passes through the motor end cover 45 and connects to the PCBA 48. The control elements on the PCBA 48 can control the current in the stator coil based on the actual position of the motor rotor 42 detected by the magnetic braiding sensor, performing closed-loop control of the motor rotor 42 and improving the control accuracy of the motor rotor 42's position.

[0082] A cover 8 is also provided outside the servo drive mechanism 4. The cover 8 is fixed to the valve body 1 with its opening facing the valve body 1, and covers the servo drive mechanism 4, including the motor housing 44, motor end cover 45, sealing cover 47, and PCBA 48, inside the cover 8. An electrical interface 81 is provided on one side of the cover 8, and the electrical interface 81 is electrically connected to the PCBA 48. Specifically, the electrical interface 81 can be provided with three different interfaces: a control signal interface, a CAN signal interface, and an RS232 signal interface. It can also be provided with one or two interfaces, including the control signal interface, or only one electrical interface 81 can be provided, through which at least one of the above three signals, including the control signal, can be transmitted.

[0083] In some embodiments of the rotary direct-drive servo spool valve of this application, such as Figures 2 to 5 A valve sleeve 7 is also provided between the valve body 1 and the valve core 2. The structure of the valve sleeve 7 is as follows: Figure 10 As shown, multiple valve sleeve ports are provided on the outer circumferential surface of the valve sleeve 7, penetrating the wall of the valve sleeve 7 and connecting the valve sleeve cavity. Specifically, the valve sleeve ports include valve sleeve first T-port 74, valve sleeve B-port 73, valve sleeve P-port 71, valve sleeve A-port 72 and valve sleeve second T-port 75 arranged sequentially in the axial direction of the valve sleeve 7. The valve sleeve first T-port 74, valve sleeve B-port 73, valve sleeve P-port 71, valve sleeve A-port 72 and valve sleeve second T-port 75 are all provided on the same circumferential surface of the valve sleeve 7.

[0084] A valve sleeve retainer 76 is provided at one end of the valve sleeve 7 near the first T-port 74. The valve sleeve 7 is installed in the main bore 11 of the valve body 1, such that the retainer 76 is located at the end where the end cap 5 is located. The valve sleeve 7 and the valve body 1 are sealed by a gap. The retainer 76 is pressed against the valve body 1 around the main bore 11 by the inner end face of the end cap 5, preventing axial movement of the valve sleeve 7 within the main bore 11. Alternatively, a sealing ring can also be used to seal the valve sleeve 7 and the valve body 1.

[0085] After the valve sleeve 7 is installed in the main hole 11 of the valve body, the first T port 74 of the valve sleeve is connected to the first T cavity 15, the B port 73 of the valve sleeve is connected to the B cavity 14, the P port 71 of the valve sleeve is connected to the P cavity 12, the A port 72 of the valve sleeve is connected to the A cavity 13, and the second T port 75 of the valve sleeve is connected to the second T cavity 16.

[0086] The valve core 2 is installed inside the valve sleeve cavity of the valve sleeve 7 and can move axially along the valve sleeve cavity under the drive of the transmission mechanism 3. When there is a clearance fit between the valve core 2 and the valve sleeve 7, the wear between the valve core 2 and the valve sleeve 7 can be reduced when the valve core 2 slides. At the same time, the clearance fit between the valve core 2 and the valve sleeve 7, as well as the clearance seal or sealing ring seal between the valve sleeve 7 and the valve body 1, can buffer the tangential stress brought by the transmission mechanism 3, ensuring the smooth sliding of the valve core 2 within the valve sleeve 7.

[0087] The different axial positions of valve core 2 within valve sleeve 7 allow valve core 2 to be in three different valve position states. When valve core 2 is in the neutral position, such as... Figure 4 As shown, the outer circumferential surface of the valve core 2 closes the valve sleeve A port 72 and valve sleeve B port 73. The first connecting groove 23 is connected to the first T port 74 of the valve sleeve, the second connecting groove 24 is connected to the valve sleeve P port 71, and the third connecting groove 25 is connected to the second T port 75 of the valve sleeve. At this time, the valve position function of the rotary direct-drive servo spool valve of this application is as follows: Figure 11 As shown, the P port 101, T port 102, A port 103 and B port 104 on the valve body 1 are isolated from each other, and there is no hydraulic oil supply in the oil circuits connected to A port 103 and B port 104.

[0088] When valve core 2 is in the left position, such as Figure 12 As shown, the first connecting groove 23 on the outer circumference of the valve core 2 is connected to the first T-port 74 of the valve sleeve, the second connecting groove 24 is connected to both the P-port 71 and the B-port 73 of the valve sleeve, and the third connecting groove 25 is connected to both the A-port 72 and the second T-port 75 of the valve sleeve. At this time, the valve position function of the rotary direct-drive servo spool valve of this application is as follows: Figure 13 As shown, port P 101 on valve body 1 is connected to port B 104, and port A 103 is connected to port T 102. Hydraulic oil from port P 101 flows to the hydraulic equipment through port B 104, and return oil from the hydraulic equipment flows to port T 102 through port A 103, returning to the oil tank. The specific position of the control valve core 2 can also control the valve opening size between the second connecting groove 24 and port B 73 of the valve sleeve, and the valve opening size between the third connecting groove 25 and port A 72 of the valve sleeve, thereby controlling the flow rate of hydraulic oil flowing to the hydraulic equipment through port B 104.

[0089] When valve core 2 is in the right position, such as Figure 14 As shown, the first connecting groove 23 on the outer circumferential surface of the valve core 2 is simultaneously connected to both the valve sleeve B port 73 and the valve sleeve first T port 74; the second connecting groove 24 is simultaneously connected to both the valve sleeve P port 71 and the valve sleeve A port 72; and the third connecting groove 25 is connected to the valve sleeve second T port 75. At this time, the valve position function of the rotary direct-drive servo spool valve of this application is as follows: Figure 15 As shown, port P 101 on valve body 1 is connected to port A 103, and port B 104 is connected to port T 102. Hydraulic oil from port P 101 flows to the hydraulic equipment through port A 103, and return oil from the hydraulic equipment flows to port T 102 through port B 104, returning to the oil tank. The specific position of the control valve core 2 can also control the valve opening size between the first connecting groove 23 and valve sleeve port B 73, and the valve opening size between the second connecting groove 24 and valve sleeve port A 72, thereby controlling the flow rate of hydraulic oil flowing to the hydraulic equipment through port A 103.

[0090] In the description of this application, the references to terms such as "an embodiment," "specific embodiment," and "preferred embodiment" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this application, 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.

[0091] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A rotary direct-drive servo spool valve, characterized in that: The device includes a valve body (1), a valve core (2), a transmission mechanism (3), and a servo drive mechanism (4). The valve body (1) is provided with multiple hydraulic ports and multiple valve chambers that are respectively connected to the hydraulic ports. The valve core (2) is disposed in the valve body (1) and can slide relative to the valve body (1) to switch the connection relationship between the valve chambers. The valve core (2) is provided with an axially extending valve core hole (21). The transmission mechanism (3) extends from one end of the valve core (2) into the valve core hole (21) and is connected to the end area of ​​the other end of the valve core (2). The output shaft of the servo drive mechanism (4) is provided with an eccentric mechanism (41) and is connected to the transmission mechanism (3) through the eccentric mechanism (41) so that the valve core (2) can be driven to slide through the transmission mechanism (3).

2. The rotary direct-drive servo spool valve according to claim 1, characterized in that: A transmission connecting plate (22) is provided in the end area of ​​the valve core hole (21) away from the servo drive mechanism (4). The periphery of the transmission connecting plate (22) is integrally connected to the wall of the valve core hole (21), and the transmission mechanism (3) is integrally connected to the middle part of the transmission connecting plate (22).

3. The rotary direct-drive servo spool valve according to claim 2, characterized in that: The transmission mechanism (3) includes a transmission rod (31), the end of which is connected to the transmission connecting plate (22). The cross-section of the transmission rod (31) is a rectangle with a height parallel to the output shaft of the servo drive mechanism (4), and the length of the upper and lower bottom edges of the rectangle is less than the height of the rectangle. Deformation buffer holes (221) are provided on both sides of the transmission rod (31) in the height direction at the connection between the transmission connecting plate (22) and the transmission rod (31).

4. The rotary direct-drive servo spool valve according to claim 1, characterized in that: The transmission mechanism (3) includes a transmission sleeve (32), and the eccentric mechanism (41) includes an eccentric rod (411). The eccentric rod (411) is connected to the output shaft of the servo drive mechanism (4) and is eccentrically disposed with respect to the output shaft of the servo drive mechanism (4). The transmission sleeve (32) is sleeved on the eccentric rod (411) and is rotatably connected to the eccentric rod (411).

5. The rotary direct-drive servo spool valve according to claim 4, characterized in that: The eccentric mechanism (41) further includes an eccentric connecting wheel (412), an eccentric connecting rod (413), and an eccentric mechanism rotating shaft (414). The eccentric connecting wheel (412) is fixed on the output shaft of the servo drive mechanism (4). The eccentric rod (411) is fixed at the periphery of the eccentric connecting wheel (412). One end of the eccentric connecting rod (413) is connected to the eccentric rod (411), and the other end is connected to the eccentric mechanism rotating shaft (414). The eccentric mechanism rotating shaft (414) is coaxially arranged with the output shaft of the servo drive mechanism (4) and rotatably connected to the valve body (1).

6. The rotary direct-drive servo spool valve according to claim 1, characterized in that: It also includes an end cap (5) and an elastic centering device (6). The end cap (5) is fixed on the valve body (1). The elastic centering device (6) is disposed on the inner side of the end cap (5) and connected to the valve core (2) so as to generate a pushing force to push the valve core (2) back to the center position.

7. The rotary direct-drive servo spool valve according to claim 6, characterized in that: The elastic centering device (6) includes a first spring seat (61), a spring seat connector (62), a centering spring (63), and a second spring seat (64). The spring seat connector (62) passes through the first spring seat (61) and the second spring seat (64) and is fixed to the end of the valve core (2), and is slidably connected with the first spring seat (61) and the second spring seat (64). The centering spring (63) is sleeved on the spring seat connector (62) and is disposed between the first spring seat (61) and the second spring seat (64). The first spring seat (61) abuts against the end cap (5), and the second spring seat (64) abuts against the valve body (1).

8. The rotary direct-drive servo spool valve according to claim 1, characterized in that: The servo drive mechanism (4) is fixed to the side of the valve body (1). The output shaft of the servo drive mechanism (4) is perpendicular to the valve core (2). The servo drive mechanism (4) includes a motor rotor (42), a motor stator (43), a motor housing (44), and a motor end cover (45). The motor housing (44) is fixed on the valve body (1). The motor stator (43) is fixed inside the motor housing (44). The motor rotor (42) is located inside the motor stator (43). The motor end cover (45) is fixed at the end of the motor housing (44) away from the valve body (1). One end of the motor rotor (42) is rotatably connected to the motor housing (44), and the other end is rotatably connected to the motor end cover (45) through an end cover bearing (451). A wave washer (452) is provided between the end of the end cover bearing (451) and the motor end cover (45).

9. The rotary direct-drive servo spool valve according to claim 8, characterized in that: The motor rotor (42) is provided with an induction magnetic braid (46) at one end near the motor end cover (45). A sealing cover (47) is provided on the outside of the motor end cover (45). The sealing cover (47) is sealed to the motor end cover (45). The induction magnetic braid (46) is located inside the sealing cover (47). A PCBA (48) is provided on the outside of the sealing cover (47). A magnetic braid induction element is provided on the PCBA (48). The magnetic braid induction element is correspondingly provided with the induction magnetic braid (46).

10. The rotary direct-drive servo spool valve according to any one of claims 1-9, characterized in that: It also includes a valve sleeve (7), which is disposed inside the valve body (1). The valve sleeve (7) is provided with a plurality of valve sleeve holes connected to the valve cavity. The valve core (2) is slidably disposed inside the valve sleeve (7). The valve sleeve (7) and the valve body (1) are sealed with a gap, and the valve core (2) and the valve sleeve (7) are fitted with a gap.

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