Hydraulic servo valve with rotary structure

Abstract

The utility model discloses a hydraulic servo valve with a rotary structure, which comprises a valve body, the valve body is provided with a plurality of oil ports and corresponding oil cavities, and one end port of each oil cavity is arranged on the same mounting surface; a torque motor is arranged at one end of the valve body, a fixed valve disc and a rotating valve disc are arranged in a valve disc cavity at the other end of the valve body, oil grooves which are independently communicated with all oil cavities are formed in the fixed valve disc in a penetrating mode, and a plurality of blind holes are formed in the rotating valve disc towards the fixed valve disc. Comprising a transmission shaft driven by a torque motor, the torque motor drives the transmission shaft to rotate, the rotating valve disc is driven to rotate relative to the fixed valve disc, the communication state of the blind hole and the oil groove is changed, and the flow direction and size of liquid in the valve body are adjusted. By changing the corresponding state of the blind holes and the oil grooves, namely closing the oil grooves or communicating the adjacent oil grooves, the direction and size of liquid flow in the valve body are adjusted, the response speed is high, and the control precision is high.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic servo valve technology, and in particular to a rotary hydraulic servo valve. Background Technology

[0002] Hydraulic servo valves are core components in hydraulic control systems used for high-precision automatic control mechanisms. With the increasing automation of industrial machinery, the functional and performance requirements of hydraulic control components are constantly rising. In a strip web guiding control system, there are unwinding web guiding control, intermediate process web guiding control, and winding web guiding control. As the core control component, the hydraulic servo valve requires very high response speed and control precision to ensure that the two sides of the coiled strip remain aligned after winding. During the automatic control of strip web guiding, photoelectric sensors detect the strip edge and transmit photoelectric signals to the web guiding controller. After signal comparison, a command signal is sent to the hydraulic servo valve, thereby controlling the automatic operation of the web guiding mechanism. Simultaneously, during coil changing, the winding machine or unwinding machine needs to be stationary in a fixed position. To solve this problem, one approach is to use a proportional servo valve with a safety position, but this is unsuitable for high-speed production lines. Another approach is to use a servo valve with a shut-off valve in the working circuit, but this increases equipment cost and complicates control. Utility Model Content

[0003] The purpose of this utility model is to provide a rotary hydraulic servo valve that addresses the shortcomings of existing technologies. It has a simple and compact structure, fast response speed, and high control accuracy, and is especially suitable for hydraulic correction automatic control systems, which can well meet the specific requirements of the equipment.

[0004] To solve the above-mentioned technical problems, the present invention provides a technical solution as follows: A rotary hydraulic servo valve includes a valve body with multiple oil ports, each oil port being connected to an oil chamber, and the oil chambers being disposed on the same mounting surface relative to the other end of the oil ports; a torque motor is provided at one end of the valve body, and a valve disc cavity is provided at the other end, with a fixed valve disc and a rotating valve disc disposed within the valve disc cavity; the fixed valve disc is fixedly fitted to the mounting surface, and the fixed valve disc is provided with an oil groove that communicates individually with each oil chamber; the rotating valve disc is provided with multiple blind holes facing the fixed valve disc; wherein, a drive shaft is rotatably connected to the valve body, one end of the drive shaft is connected to the torque motor, and the other end is circumferentially fixedly connected to the rotating valve disc; the torque motor drives the drive shaft to rotate, driving the rotating valve disc to rotate relative to the fixed valve disc, changing the communication state between the blind holes and the oil groove, and adjusting the direction and magnitude of the liquid flow in the valve body.

[0005] Furthermore, the oil port includes at least a pressure oil port P, a working oil port A, a working oil port B, and a return oil port T. The valve body is provided with an oil supply chamber communicating with the pressure oil port P, a first working oil chamber communicating with the working oil port A, a second working oil chamber communicating with the working oil port B, and a return oil chamber communicating with the return oil port T. The fixed valve disc is provided with an oil supply groove communicating with the oil supply chamber, a first working oil groove communicating with the first working oil chamber, a second working oil groove communicating with the second working oil chamber, and a return oil groove communicating with the return oil chamber.

[0006] Furthermore, in the initial working state, the blind hole corresponds to the first working oil groove and the second working oil groove, sealing the first working oil chamber and the second working oil chamber; when the servo valve receives a positive command, the rotating valve disc rotates forward relative to the fixed valve disc, the blind hole connects the first working oil groove and the return oil groove and the second working oil groove and the supply oil groove, the first working oil chamber and the return oil chamber are connected, and the supply oil chamber and the second working oil chamber are connected; when the servo valve receives a reverse command, the rotating valve disc rotates in the reverse direction relative to the fixed valve disc, the blind hole connects the first working oil groove and the supply oil groove and the second working oil groove and the return oil groove, the supply oil chamber is connected to the first working oil chamber, and the second working oil chamber is connected to the return oil chamber.

[0007] Furthermore, it includes a gap adjustment device, wherein a gap X1 is provided between the end face of the gap adjustment device and the end face corresponding to the drive shaft, and a gap X2 is provided between the fixed valve disc and the rotating valve disc. By adjusting the size of the gap X1, the size of the gap X2 can be controlled, and the dynamic balance of the gap X2 under pressure fluctuations can be maintained.

[0008] Furthermore, in the initial working state, the rotating valve disc is in a balanced position, and the gaps X1 and X2 are in their initial state, with no flow from working port A and working port B. The balance relationship between the gaps X1 and X2 is as follows: when the gap X2 increases, the gap X1 decreases, causing the pressure inside the valve disc cavity to increase, driving the rotating valve disc to move toward the fixed valve disc to reset; when the gap X2 decreases, the gap X1 increases, causing the pressure inside the valve disc cavity to decrease, driving the rotating valve disc to move away from the fixed valve disc to reset.

[0009] Furthermore, in the initial working state, the oil supply chamber and the oil return chamber are connected through a gap X2 to form a liquid circuit.

[0010] Furthermore, the end of the drive shaft facing the valve disc cavity is provided with a return hole, and the valve disc cavity and the oil return cavity are connected through the return hole.

[0011] Furthermore, the torque motor includes a rotor, an excitation coil, and a permanent magnet arranged sequentially from the inside to the outside, and the rotor is rigidly connected to the transmission shaft.

[0012] Furthermore, a centering spring is connected to one end of the drive shaft facing the torque motor, and the drive shaft is jointly controlled by the driving force of the torque motor and the restoring force of the centering spring.

[0013] Furthermore, it also includes a manual adjustment knob, mechanically connected to the drive shaft, for manually rotating to adjust the rotation angle of the rotating valve disc.

[0014] The rotary hydraulic servo valve provided by this utility model, compared with the prior art, achieves a simple and compact structure, fast response speed, and high control precision by setting multiple oil chamber ports on the same standard mounting plane and by using a fixed valve disc that is fixed to the mounting surface and a rotating valve disc that is rotatably connected to the fixed valve disc. It is particularly suitable for hydraulic automatic correction control systems. By changing the corresponding state of the blind hole and the oil groove—that is, closing the oil groove or connecting adjacent oil grooves—the direction and magnitude of the liquid flow in the valve body can be adjusted, flexibly and accurately controlling the static and working states of the winding machine or unwinding machine, thus well meeting the specific requirements of the equipment. In particular, the gap adjustment device allows for effective control of the gap X2 between the fixed valve disc and the rotating valve disc by adjusting the gap X1, maintaining the dynamic balance of gap X2 under pressure fluctuations, further improving the sensitivity and accuracy of the hydraulic servo valve. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the figures in the drawings do not constitute a limitation on scale.

[0016] Figure 1 This is a schematic diagram of the rotary hydraulic servo valve structure in an embodiment of this utility model;

[0017] Figure 2 This is a schematic diagram illustrating the working principle of the rotary hydraulic servo valve in this embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the fixed valve structure in an embodiment of this utility model;

[0019] Figure 4 This is a schematic diagram of the rotary valve structure in an embodiment of this utility model.

[0020] Explanation of reference numerals in the attached drawings: 1. Manual adjustment knob; 2. Centering spring; 3. Excitation coil; 4. Rotor; 5. Protective cover; 6. Permanent magnet; 7. Drive shaft; 71. Return hole; 8. Bearing; 9. Fixed valve disc; 901. First working oil groove; 902. Second working oil groove; 903. Supply oil groove; 904. Return oil groove; 10. Rotating valve disc; 101. Blind hole; 11. Gap adjustment device; 12. Valve body; 120. Valve disc cavity; 121. First working oil chamber; 122. Second working oil chamber; 123. Supply oil chamber; 124. Return oil chamber; 125. Mounting surface. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the various embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this utility model to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0022] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0023] like Figure 1-4As shown, one embodiment of this utility model relates to a rotary hydraulic servo valve, including a valve body 12. The valve body 12 has multiple oil ports, each oil port being connected to an oil chamber. The oil chambers are disposed on the same mounting surface 125 relative to the other ends of each oil port. One end of the valve body 12 is provided with a torque motor, and the other end is provided with a valve disc cavity 120. The valve disc cavity 120 is provided with a fixed valve disc 9 and a rotating valve disc 10. The fixed valve disc 9 is fixed to the mounting surface 125 and has an oil groove that is individually connected to each oil chamber. The rotating valve disc 10 has multiple blind holes 101 facing the fixed valve disc 9. The valve body 12 is rotatably connected to a... A drive shaft 7 is provided, one end of which is connected to the torque motor, and the other end is circumferentially fixedly connected to the rotating valve disc 10. The torque motor provides rotational driving force to the drive shaft 7, which drives the drive shaft 7 to rotate. This drives the rotating valve disc 10 to rotate relative to the fixed valve disc 9, thereby changing the communication state between the blind hole 101 and the oil groove of the fixed valve disc 9. For example, the blind hole 101 can be used to close the oil groove or connect adjacent oil grooves, changing the communication state between the various oil chambers and adjusting the direction and magnitude of the liquid flow in the valve body 12. Thus, the servo valve can output a working flow rate corresponding to an external command signal, controlling the speed and direction of the load operation. Preferably, the mounting surface 125 for mounting the fixed valve disc 9 conforms to the ISO 4401 standard. The fixed valve disc 9 is fixedly connected to the mounting surface 125 by bolts, increasing the convenience of installing the fixed valve disc 9.

[0024] In an exemplary example, the rotary hydraulic servo valve includes a valve body 12. One end of the valve body 12 is connected to a torque motor. The torque motor includes a rotor 4, an excitation coil 3, a permanent magnet 6, and a protective cover 5 for supporting and protecting the overall structure of the torque motor, arranged sequentially from the inside to the outside. The rotor 4 is rigidly connected to a drive shaft 7, which is rotatably connected to the valve body 12 via a bearing 8. The other end of the valve body 12 has a valve disc cavity 120. The valve disc cavity 120 has an ISO4401 standard mounting surface 125. The valve disc cavity 120 has a fixed valve disc 9 and a rotating valve disc 10. The fixed valve disc 9 is fitted and fixed to the mounting surface 125, and the rotating valve disc 10 is inserted through the valve body 12. The internal drive shaft 7 is axially fixedly connected; the valve body 12 is provided with multiple oil ports, including at least a pressure oil port P, a working oil port A, a working oil port B, and a return oil port T. The valve body 12 is provided with an oil supply chamber 123 communicating with the pressure oil port P, a first working oil chamber 121 communicating with the working oil port A, a second working oil chamber 122 communicating with the working oil port B, and a return oil chamber 124 communicating with the return oil port T. The fixed valve disc 9 is provided with an oil supply groove 903 communicating with the oil supply chamber 123, a first working oil groove 901 communicating with the first working oil chamber 121, a second working oil groove 902 communicating with the second working oil chamber 122, and a return oil groove 904 communicating with the return oil chamber 124. Thus, by changing the communication state of the oil grooves, the flow rate and direction of the liquid in the oil chambers within the valve body 12 can be adjusted. Preferably, a centering spring 2 is connected to one end of the drive shaft 7 facing the torque motor. The drive shaft 7 is controlled by the driving force of the torque motor and the restoring force of the centering spring 2. Under the combined action of the torque motor and the centering spring 2, the drive shaft 7 swings left and right. The swing angle and direction depend on the input current of the excitation coil 3 and the balancing force of the centering spring 2. By balancing the rotational torque of the torque motor rotor 4 through the four centering springs 2, the balance state of the rotating valve disc 10 is achieved, and the rotation angle of the rotating valve disc 10 is precisely controlled.

[0025] In the initial working state, the rotary hydraulic servo valve has no command signal input. The blind hole 101 corresponds to the first working oil groove 901 and the second working oil groove 902, closing the first working oil chamber 121 and the second working oil chamber 122. The working oil port A and the working oil port B have no load flow.

[0026] When the servo valve receives a positive command signal, it inputs a working current corresponding to the command signal to the torque motor excitation coil 3. After overcoming the deformation force of the centering spring 2, the torque motor rotor 4 drives the rotating valve disc 10 to rotate by the corresponding angle. The rotating valve disc 10 rotates positively relative to the fixed valve disc 9. The blind hole 101 of the rotating valve disc 10 is misaligned with the first working oil groove 901 and the second working oil groove 902, connecting the first working oil groove 901 with the return oil groove 904 and the second working oil groove 902 with the supply oil groove 903. The first working oil chamber 121 is connected to the return oil chamber 124, and the supply oil chamber 123 is connected to the second working oil chamber 122. By changing the rotation angle of the rotating valve disc 10, the connection area of ​​the fluid channels of the first working oil chamber 121 and the return oil chamber 124, as well as the fluid channels of the supply oil chamber 123 and the second working oil chamber 122, can be changed, thereby adjusting the direction and magnitude of the load flow and achieving the working state required to drive the hydraulic mechanism.

[0027] When the servo valve receives a reverse command, it inputs a working current corresponding to the command signal to the torque motor excitation coil 3. After overcoming the deformation force of the centering spring 2, the torque motor rotor 4 drives the rotating valve disc 10 to rotate by the corresponding angle, so that the rotating valve disc 10 rotates in the opposite direction to the fixed valve disc 9. The blind hole 101 of the rotating valve disc 10 is misaligned with the first working oil groove 901 and the second working oil groove 902. The blind hole 101 connects the first working oil groove 901 with the oil supply groove and the second working oil groove 902 with the oil return groove 904. The oil supply chamber 123 is connected to the first working oil chamber 121, and the second working oil chamber 122 is connected to the oil return chamber 124. According to different command signals, the rotation angle of the rotating valve disc 10 is adjusted, changing the connection area of ​​the fluid channels between the oil supply chamber 123 and the first working oil chamber 121 and the second working oil chamber 122 and the oil return chamber 124, thereby adjusting the direction and magnitude of the load flow to achieve the working state required to drive the hydraulic mechanism. Preferably, four symmetrically distributed blind holes 101 are provided on the contact surface between the rotating valve disc 10 and the fixed valve disc 9. By rotating, the communication area between the blind holes 101 and the oil groove of the fixed valve disc 9 is changed, thereby realizing the directional connection and flow regulation between the oil supply chamber 123 and the working oil chamber.

[0028] One embodiment involves a rotary hydraulic servo valve. The end of the drive shaft 7 facing the torque motor is mechanically connected to a manual adjustment knob 1. In the event of a torque motor failure that cannot provide driving torque, the drive shaft 7 can be rotated in both directions using the manual adjustment knob 1 to drive the rotating valve disc 10 to rotate, thereby controlling the output of the servo valve's load flow and performing emergency work.

[0029] One embodiment relates to a rotary hydraulic servo valve. The valve disc cavity 120 is provided with a clearance adjustment device 11 corresponding to the axial direction of the end of the drive shaft 7. In one example, the clearance adjustment device 11 is a balance bolt. The end of the drive shaft 7 facing the valve disc cavity 120 is provided with a return hole 71. The valve disc cavity 120 and the return oil cavity 124 are connected through the return hole 71. A clearance X1 is provided between the end face of the clearance adjustment device 11 and the end face corresponding to the drive shaft 7. A clearance X2 is provided between the fixed valve disc 9 and the rotating valve disc 10. By adjusting the size of the clearance X1, the size of the clearance X2 can be controlled to maintain the dynamic balance of the clearance X2 under pressure fluctuations. In the initial working state, the blind hole 101 closes the first working oil tank 901 and the second oil supply tank. The pressurized liquid leaks through the oil supply chamber 123 and the oil supply tank 903 from the tiny gap X2 between the fixed valve disc 9 and the rotating valve disc 10 to the return oil chamber 124 and the valve disc chamber 120. The liquid that leaks into the valve disc chamber 120 then enters the return oil chamber 124 through the gap X1 and the small hole on the right end face of the drive shaft 7, and flows out from the return oil port T. There is no flow from the working oil port A and the working oil port B. Between the fixed valve disc 9 and the rotating valve disc 10, the pressure of the fluid creates a thrust on the rotating valve disc 10 in the areas of the supply oil groove 903, return oil groove 904, first working oil groove 901, and second working oil groove 902, pushing the rotating disc away from the fixed valve disc 9. Simultaneously, the pressure of the fluid in the valve disc cavity 120 flows into the return oil cavity 124 through gap X1 and return hole 71, creating a pressure difference between the valve disc cavity 120 and the return oil cavity 124. This pressure difference drives the rotating valve disc 10 closer to the fixed valve disc 9 until gaps X1 and X2 reach an equilibrium. By changing the size of gap X1, the pressure difference between the valve disc cavity 120 and the return oil cavity 124 can be altered, changing the equilibrium state of gaps X1 and X2, thus changing the position of the rotating valve disc 10 relative to the fixed valve disc 9, achieving adjustment and control of gap X1. This ensures that the contact surfaces between the fixed valve disc 9 and the rotating valve disc 10 maintain a certain gap, preventing friction between the two relatively rotating planes from affecting the working performance of the servo valve. At the same time, the gap between the two relatively rotating planes is small enough to seal the first working oil groove 901 and the second working oil groove 902, so that no flow can be discharged from working oil port A and working oil port B.

[0030] When the rotating valve disc 10 rotates relative to the fixed valve disc 9, connecting the oil supply chamber 123, the working oil chamber, and the return oil chamber 124, the gap X2 between the rotating valve disc 10 and the fixed valve disc 9 increases accordingly under the action of pressurized fluid, causing the gap X1 to decrease. This increases the resistance to fluid flow from the valve disc cavity 120 to the return oil chamber 124, resulting in increased pressure within the valve disc cavity 120. Consequently, the thrust applied to the rotating valve disc 10 increases, driving the rotating valve disc 10 to move and reset towards the fixed valve disc 9. When the gap X2 decreases and the gap X1 increases, the pressure in the valve disc cavity 120 decreases, driving the rotating valve disc 10 to move and reset away from the fixed valve disc 9. This maintains the dynamic balance of the rotating valve disc 10's position, improving the frequency response and control accuracy of the hydraulic servo valve.

[0031] The rotary hydraulic servo valve provided by this utility model, compared with the prior art, achieves a simple and compact structure, fast response speed, and high adjustment accuracy by setting multiple oil chamber ports on the same standard mounting plane and by using a fixed valve disc that is fixed to the mounting surface and a rotating valve disc that is rotatably connected to the fixed valve disc. It is particularly suitable for hydraulic automatic correction control systems. By changing the corresponding state of the blind hole and the oil groove—that is, closing the oil groove or connecting adjacent oil grooves—the direction and magnitude of the liquid flow in the valve body can be adjusted, flexibly and accurately controlling the static and working states of the winding machine or unwinding machine, thus well meeting the specific requirements of the equipment. In particular, the gap adjustment device allows for effective control of the gap X2 between the fixed valve disc and the rotating valve disc by adjusting the gap X1, maintaining the dynamic balance of gap X2 under pressure fluctuations, further improving the sensitivity and accuracy of the hydraulic servo valve.

[0032] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A rotary hydraulic servo valve, characterized in that, The system includes a valve body (12), which has multiple oil ports, each of which is connected to an oil chamber. The oil chambers are located on the same mounting surface (125) relative to the other end of the oil ports. One end of the valve body (12) is provided with a torque motor, and the other end is provided with a valve disc cavity (120). The valve disc cavity (120) is provided with a fixed valve disc (9) and a rotating valve disc (10). The fixed valve disc (9) is fitted and fixed to the mounting surface (125). The fixed valve disc (9) is provided with an oil groove that is individually connected to each oil chamber. The rotating valve disc (10) is provided with multiple blind holes (101) facing the fixed valve disc (9). The valve body (12) is rotatably connected to a drive shaft (7). One end of the drive shaft (7) is connected to the torque motor, and the other end is circumferentially fixed to the rotating valve disc (10). The torque motor drives the drive shaft (7) to rotate, which drives the rotating valve disc (10) to rotate relative to the fixed valve disc (9), changing the communication state between the blind hole (101) and the oil tank, and adjusting the direction and magnitude of the liquid flow in the valve body (12).

2. The rotary hydraulic servo valve according to claim 1, characterized in that, The oil ports include at least a pressure port P, a working port A, a working port B, and a return port T. The valve body (12) is provided with a supply oil chamber (123) communicating with the pressure port P, a first working oil chamber (121) communicating with the working port A, a second working oil chamber (122) communicating with the working port B, and a return oil chamber (124) communicating with the return port T. The fixed valve disc (9) is provided with a supply oil groove (903) communicating with the supply oil chamber (123), a first working oil groove (901) communicating with the first working oil chamber (121), a second working oil groove (902) communicating with the second working oil chamber (122), and a return oil groove (904) communicating with the return oil chamber (124).

3. The rotary hydraulic servo valve according to claim 2, characterized in that, In the initial working state, the blind hole (101) corresponds to the first working oil groove (901) and the second working oil groove (902), closing the first working oil chamber (121) and the second working oil chamber (122). When the servo valve receives a positive command, the rotating valve disc (10) rotates positively relative to the fixed valve disc (9), and the blind hole (101) connects the first working oil groove (901) with the return oil groove (904) and the second working oil groove (902) with the supply oil groove (903). The first working oil chamber (121) The oil supply chamber (123) is connected to the return oil chamber (124), and the oil supply chamber (123) is connected to the second working oil chamber (122). When the servo valve receives a reverse command, the rotating valve disc (10) rotates in the opposite direction to the fixed valve disc (9). The blind hole (101) connects the first working oil groove (901) and the oil supply groove, and the second working oil groove (902) and the return oil groove (904). The oil supply chamber (123) is connected to the first working oil chamber (121), and the second working oil chamber (122) is connected to the return oil chamber (124).

4. The rotary hydraulic servo valve according to claim 3, characterized in that, It includes a gap adjustment device (11), with a gap X1 between the end face of the gap adjustment device (11) and the end face corresponding to the drive shaft (7), and a gap X2 between the fixed valve disc (9) and the rotating valve disc (10). By adjusting the size of the gap X1, the size of the gap X2 can be controlled, and the dynamic balance of the gap X2 under pressure fluctuations can be maintained.

5. The rotary hydraulic servo valve according to claim 4, characterized in that, In the initial working state, the rotating valve disc (10) is in a balanced position, the gaps X1 and X2 are in their initial state, and there is no flow from working port A and working port B. The balance relationship between the gaps X1 and X2 is that when the gap X2 increases, the gap X1 decreases, causing the pressure in the valve disc cavity (120) to increase, driving the rotating valve disc (10) to move toward the fixed valve disc (9) to reset. When the gap X2 decreases, the gap X1 increases, causing the pressure in the valve disc cavity (120) to decrease, driving the rotating valve disc (10) to move away from the fixed valve disc (9) to reset.

6. The rotary hydraulic servo valve according to claim 5, characterized in that, In the initial working state, the oil supply chamber (123) and the oil return chamber (124) are connected through a gap X2 to form a liquid circuit.

7. The rotary hydraulic servo valve according to claim 6, characterized in that, The drive shaft (7) has a return hole (71) at one end facing the valve disc cavity (120), and the valve disc cavity (120) and the oil return cavity (124) are connected through the return hole (71).

8. The rotary hydraulic servo valve according to claim 1, characterized in that, The torque motor includes a rotor (4), an excitation coil (3), and a permanent magnet (6) arranged sequentially from the inside to the outside. The rotor (4) is rigidly connected to the transmission shaft (7).

9. The rotary hydraulic servo valve according to claim 8, characterized in that, The drive shaft (7) is connected to a centering spring (2) at one end facing the torque motor. The drive shaft (7) is controlled by the driving force of the torque motor and the reset force of the centering spring (2).

10. The rotary hydraulic servo valve according to any one of claims 1-9, characterized in that, It also includes a manual adjustment knob (1), which is mechanically connected to the drive shaft (7) for manually rotating to adjust the rotation angle of the rotating valve disc (10).

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