Electro-hydraulic dual-redundancy control locking valve for electro-static pressure servo system

Abstract

The invention relates to an electro-hydraulic dual-redundancy control locking valve for an electro-static pressure servo system, and belongs to the technical field of aerospace servo actuation. Comprising a locking screw, an electromagnet, a magnetic core pipe, a pilot spring, an armature, a pilot valve element, a supporting spring, a spring seat, a valve sleeve, a main valve element, a ball plug, a nut, a hydraulic pilot valve element and a limiting nut. The scheme that an electromagnet is electrified to attract a pilot valve element and high-pressure oil actively acts on the pilot valve element is adopted, the pilot valve element controlled by the electromagnet, a valve element controlled by hydraulic pressure and a main valve element are coaxially arranged and installed in the same valve sleeve, the only main valve element is controlled by the electromagnet and the high-pressure oil to be opened, and therefore the locking function of the valve can be guaranteed, and the locking function of the valve can be achieved. And the function of opening the valve by the working pressure of the actuating system after the power supply of the electromagnet fails can be ensured. Redundancy of the opening mode of the locking valve is achieved, and reliable locking and opening of the valve are guaranteed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace servo actuation, and relates to an electro-hydraulic double-redundancy control locking valve for an electrostatic pressure servo system. BACKGROUND

[0002] The electrostatic pressure servo actuator is applied to an aerospace vehicle, such as a landing gear retraction system, an attitude control surface, an engine nozzle and the like. A reliable locking function is needed to realize the locking control function of the controlled device. At present, the combination of a hydraulic lock and an electromagnetic locking valve is adopted to realize the locking function

[0003] The hydraulic lock needs to continuously control the pilot valve core at high pressure, and the hydraulic lock located in the two-cavity oil circuit is a single-point failure link. The electromagnetic locking valve usually adopts a cone valve or a specially designed structure to realize the locking function, and almost has no leakage and high locking reliability. However, the electromagnet is prone to failure and also belongs to a single-point failure link, that is, the locking function is lost after the electromagnet fails. Therefore, a locking valve with redundant control and simple structure is needed. The current product status includes:

[0004] In the description of "a high-reliability static pressure locking system" (application publication number CN 112460098 A), the electromagnetic locking valve and the bidirectional hydraulic lock can realize the locking function for the two cavities of the actuator. When the electromagnetic lock fails, the bidirectional hydraulic lock circuit can still ensure the normal function of the system. The two locking valves are set in parallel, so that the electrostatic pressure servo actuator has double-redundancy function and high reliability. However, this method increases two hydraulic locks or two electromagnetic locking valves, complicates the installation of the oil circuit of the shell, increases the weight of the servo actuator, and increases the product cost. SUMMARY

[0005] The technical problem solved by the application is to overcome the shortcomings of the prior art, and to provide an electro-hydraulic double-redundancy control locking valve for an electrostatic pressure servo system, which realizes the high-reliability locking and actuation functions of the electrostatic pressure servo actuator, simplifies product design, reduces product weight and cost, and improves product efficiency.

[0006] The technical solution of the application is:

[0007] An electro-hydraulic double-redundancy control locking valve for an electrostatic pressure servo system, comprising a locking screw, an electromagnet, a magnetic core tube, a pilot spring, an armature, a pilot valve core, a supporting spring, a spring seat, a valve sleeve, a main valve core, a ball plug, a nut, a hydraulic pilot valve core and a limiting nut.

[0008] The magnetic core tube is vertically arranged in an axial direction; the electromagnet is sleeved on the outer wall of the top end of the magnetic core tube; the side wall of the magnetic core tube is provided with a stepped outer circle to limit the bottom of the electromagnet; the electromagnet and the top of the magnetic core tube are located in the same plane; the locking screw is arranged on the top of the electromagnet and the magnetic core tube; the electromagnet is fixed by the cooperation of the locking screw and the threads of the magnetic core tube; the bottom of the magnetic core tube is provided with a cylindrical recess; the armature is coaxially installed in the cylindrical recess;

[0009] The main valve core is vertically arranged, and the bottom of the main valve core is provided with an opening; the ball plug is arranged in the inner cavity of the main valve core, and the opening in the bottom of the main valve core is sealed by the nut; the main valve core, the ball plug and the nut form a main valve core assembly;

[0010] The top of the armature is provided with a spring cavity; the pilot spring is installed in the spring cavity; the bottom of the armature is provided with a cylindrical inner hole; the pilot valve core is coaxially inserted into the cylindrical inner hole of the armature from bottom to top; the spring seat is sleeved on the outer wall of the pilot valve core; the supporting spring is sleeved on the outer wall of the pilot valve core, and the top of the supporting spring is in contact with the lower surface of the head end of the pilot valve core; the bottom of the supporting spring is in contact with the spring seat; the pilot spring, the armature, the pilot valve core, the supporting spring and the spring seat form a pilot valve core assembly;

[0011] The valve sleeve is a cylindrical structure arranged vertically in an axial direction; the main valve core assembly is coaxially arranged in the inner cavity of the valve sleeve; the pilot valve core assembly is arranged above the main valve core assembly, and the pilot valve core assembly is connected with the valve sleeve through the outer threads of the magnetic core tube;

[0012] The hydraulic pilot valve core is arranged in the lower inner hole of the valve sleeve and is limited by the limiting nut.

[0013] In the above-mentioned electric-hydraulic double-redundancy control locking valve for an electro-hydraulic servo system, the outer wall of the valve sleeve is provided with an oil port a, four oil ports b and four oil ports c;

[0014] The oil port a is arranged at the axial bottom end of the valve sleeve; the four oil ports b are uniformly distributed on the side wall of the valve sleeve in a circumferential direction and are located at positions corresponding to the hydraulic pilot valve core; and the four oil ports c are uniformly distributed on the side wall of the valve sleeve in a circumferential direction and are located at positions corresponding to the main valve core.

[0015] In the above-mentioned electric-hydraulic double-redundancy control locking valve for an electro-hydraulic servo system, the valve sleeve is provided with a first sealing ring, a second sealing ring, a third sealing ring, a fourth sealing ring and a fifth sealing ring;

[0016] The first sealing ring is arranged between the bottom outer wall of the hydraulic pilot valve core and the valve sleeve; the second sealing ring is arranged on the outer wall of the valve sleeve and is located below the oil port b; the third sealing ring is arranged on the outer wall of the valve sleeve and is located between the oil port b and the oil port c; the fourth sealing ring is arranged on the outer wall of the valve sleeve and is located above the oil port c; and the fifth sealing ring is arranged between the bottom outer wall of the magnetic core tube and the inner wall of the valve sleeve.

[0017] In the aforementioned electro-hydraulic dual-redundant control locking valve for an electrostatic servo system, the inner cavity of the valve sleeve is separated from the outside through the fourth and fifth sealing rings.

[0018] In the aforementioned electro-hydraulic dual-redundant control locking valve for an electro-static servo system, the locking valve is installed on one side of the main oil line of the external electro-static servo actuator, that is, the high-pressure port of the external motor pump is connected to the actuator oil chamber; the oil port b of the locking valve is connected to the high-pressure oil port of the motor pump; the oil port c is connected to the actuator oil chamber; and the pilot oil port a is connected to the main oil line of the high-pressure outlet of the pump on the other side.

[0019] In the aforementioned electro-hydraulic dual-redundant control locking valve for an electrostatic servo system, the locking valve's operating modes include locking mode and servo actuation mode.

[0020] In the aforementioned electro-hydraulic dual-redundant control locking valve for an electrostatic servo system, the working process of the locking valve in locking mode is as follows:

[0021] There is no high-pressure oil at port a, and the electromagnet is de-energized. The pilot valve core closes the pilot valve port under the action of the pilot spring. The oil chamber formed between the main valve core, the magnetic core tube, and the valve sleeve is connected to port c through the side throttle hole of the main valve core. The main valve core closes the main valve port under the action of the pilot valve core and the pilot spring. When the pressure at port c is higher than the pressure at port b, the main valve core closes the main valve port under the action of the pressure difference between the two sides of the oil, cutting off the oil circuits on both sides, that is, closing the main oil circuit on one side of the servo actuator.

[0022] In the above-mentioned electro-hydraulic dual-redundant control locking valve for an electro-static servo system, the working process of the locking valve in servo actuation mode includes two cases. One case is that the oil flows from port b through the main valve port into port c; the other case is that the oil flows from port c through the main valve port into port b.

[0023] In the electro-hydraulic dual-redundant control locking valve of the above-mentioned electrostatic servo system, the working process of oil flowing from port b through the main valve port into port c is as follows:

[0024] When the pressure at port b is higher than that at port c, the ball plug closes the pilot valve port of the main valve core under the action of the oil pressure; under the action of the oil pressure difference on both sides, the main valve core opens the main valve core port, connecting the oil circuits on both sides.

[0025] The working process of oil flowing from port c through the main valve port into port b is as follows:

[0026] When the pressure at port c is higher than that at port b and the electromagnet is energized, the pilot valve core moves upward under the combined action of the electromagnet and the pilot spring, opening the pilot valve port. The oil at port c communicates with port b through the main valve throttle orifice and the pilot valve port. Simultaneously, under the action of the high-pressure oil in the main oil circuit at the pump high-pressure outlet on the other side of port a, the hydraulic pilot valve core moves upward to its limit. Under the combined action of the pressure difference between the oil on both sides and the supporting force of the hydraulic pilot valve core, the main valve core opens its valve port, connecting the oil circuits on both sides. When the electromagnet fails and loses power, the pilot valve port closes, and the main valve core opens its valve port under the combined action of the pilot spring preload and the supporting force of the hydraulic pilot valve core, connecting the oil circuits on both sides.

[0027] In the electro-hydraulic dual-redundant control locking valve of the above-mentioned electrostatic servo system, a double-cone sealing structure is adopted in the sealing design of the main valve port. When the first sealing surface wears more than a certain amount, the main valve core enters the second sealing surface under the action of the pilot spring, ensuring the sealing effect of the main valve core in the locking working mode.

[0028] The advantages of this invention compared to the prior art are:

[0029] (1) This invention employs a locking valve scheme that combines the electromagnet's energization to engage the pilot valve core with the high-pressure hydraulic action acting on the pilot valve core. The electromagnet-controlled pilot valve core, the hydraulically controlled valve core, and the main valve core are coaxially arranged and installed in the same valve sleeve. The electromagnet and high-pressure hydraulic control operate on a single main valve core, thus ensuring both the valve's locking function and the ability to open the valve using the working pressure of the actuation system in the event of electromagnet power failure. This achieves redundancy in the locking valve's opening method, ensuring reliable locking and opening of the valve.

[0030] (2) The present invention adopts a valve core seal with a double conical surface structure and a spring in the main valve core. When the valve electromagnet is de-energized and there is no high pressure oil, the spring can quickly push the main valve core to the valve port to close and lock the oil circuit. When the first conical sealing joint surface is worn and fails, the main valve core automatically compensates and moves to the position of the second sealing ring under the action of the spring, ensuring the sealing reliability of the locking function.

[0031] (3) The present invention realizes the highly reliable locking and actuation functions of the electrostatic servo actuator, simplifies product design, reduces product weight and cost, and improves product efficiency. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the electro-hydraulic dual-redundant control locking valve of the present invention;

[0033] Figure 2 This is a diagram of the locking structure of the double-cone seal of the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to the embodiments.

[0035] This invention provides an electro-hydraulic dual-redundant control locking valve for an electrostatic servo system, which realizes highly reliable locking and actuation functions of the electrostatic servo actuator, simplifies product design, reduces product weight and cost, and improves product efficiency.

[0036] Electro-hydraulic dual-redundant control locking valve for electro-static servo systems, such as Figure 1 Specifically, the assembly includes a locking screw 1, an electromagnet 2, a magnetic core tube 3, a pilot spring 4, an armature 5, a pilot valve core 6, a support spring 7, a spring seat 8, a valve sleeve 9, a main valve core 10, a ball plug 11, a nut 12, a hydraulic pilot valve core 13, and a limiting nut 14. The magnetic core tube 3 is vertically oriented axially; the electromagnet 2 is fitted onto the top outer wall of the magnetic core tube 3; the side wall of the magnetic core tube 3 has a stepped outer circle to limit the bottom of the electromagnet 2; the tops of the electromagnet 2 and the magnetic core tube 3 are on the same plane; the locking screw 1 is located at the top of the electromagnet 2 and the magnetic core tube 3; the electromagnet 2 is fixed by the threaded engagement of the locking screw 1 with the magnetic core tube 3; a columnar groove is provided at the center of the bottom of the magnetic core tube 3; the armature 5 is coaxially installed in the columnar groove.

[0037] The main valve core 10 is vertically arranged, and an opening is provided at the bottom of the main valve core 10; the ball plug 11 is installed in the inner cavity of the main valve core 10, and the opening at the bottom of the main valve core 10 is sealed by the nut 12; the main valve core 10, the ball plug 11, and the nut 12 constitute the main valve core assembly.

[0038] The top of the armature 5 has a spring cavity; the pilot spring 4 is installed in the spring cavity; the bottom of the armature 5 has a cylindrical inner hole; the pilot valve core 6 extends coaxially from bottom to top into the cylindrical inner hole of the armature 5; the spring seat 8 is fitted on the outer wall of the pilot valve core 6; the support spring 7 is fitted on the outer wall of the pilot valve core 6, and the top of the support spring 7 contacts the lower surface of the head end of the pilot valve core 6; the bottom of the support spring 7 contacts the spring seat 8; the pilot spring 4, armature 5, pilot valve core 6, support spring 7, and spring seat 8 constitute the pilot valve core assembly.

[0039] The valve sleeve 9 is a cylindrical structure placed vertically in the axial direction; the main valve core assembly is first coaxially installed into the inner cavity of the valve sleeve 9; the pilot valve core assembly is assembled above the main valve core assembly, and the pilot valve core assembly is connected to the valve sleeve 9 through the external thread of the magnetic core tube 3.

[0040] The hydraulic pilot valve core 13 is installed in the lower inner hole of the valve sleeve 9 and is limited by the limit nut 14.

[0041] The outer wall of the valve sleeve 9 is provided with oil port a, four oil ports b, and four oil ports c. Oil port a is located at the bottom axial end of the valve sleeve 9; the four oil ports b are evenly distributed circumferentially on the side wall of the valve sleeve 9 and are located at the corresponding positions of the hydraulic pilot valve core 13; the four oil ports c are evenly distributed circumferentially on the side wall of the valve sleeve 9 and are located at the corresponding positions of the main valve core 10.

[0042] The electro-hydraulic dual-redundant control locking valve for the electro-static servo system also includes a first sealing ring 15, a second sealing ring 16, a third sealing ring 17, a fourth sealing ring 18, and a fifth sealing ring 19. Specifically, the first sealing ring 15 is disposed between the outer wall of the bottom end of the hydraulic pilot valve core 13 and the valve sleeve 9; the second sealing ring 16 is disposed on the outer wall of the valve sleeve 9 and below oil port b; the third sealing ring 17 is disposed on the outer wall of the valve sleeve 9 and between oil port b and oil port c; the fourth sealing ring 18 is disposed on the outer wall of the valve sleeve 9 and above oil port c; and the fifth sealing ring 19 is disposed between the outer wall of the bottom end of the magnetic core tube 3 and the inner wall of the valve sleeve 9.

[0043] The inner cavity of the valve sleeve 9 is separated from the outside by the fourth sealing ring 18 and the fifth sealing ring 19.

[0044] The locking valve is installed on one side of the main oil line of the external electrostatic servo actuator, that is, the high pressure port of the external motor pump is connected to the oil chamber of the actuator; the oil port b of the locking valve is connected to the high pressure oil port of the motor pump; the oil port c is connected to the oil chamber of the actuator; and the pilot oil port a is connected to the main oil line of the high pressure outlet of the pump on the other side.

[0045] The operating modes of the locking valve include locking mode and servo actuation mode.

[0046] In the locking mode, the locking valve operates as follows:

[0047] There is no high-pressure oil at port a, and the electromagnet is de-energized. The pilot valve core 6 closes the pilot valve port under the action of the pilot spring 4. The oil chamber formed between the main valve core 10, the magnetic core tube 3, and the valve sleeve 9 is connected to port c through the side throttling hole of the main valve core 10. The main valve core 10 closes the main valve port under the action of the pilot valve core 6 and the pilot spring 4. When the pressure at port c is higher than the pressure at port b, the main valve core 10 closes the main valve port under the action of the oil pressure difference on both sides, cutting off the oil circuits on both sides, that is, closing the main oil circuit on one side of the servo actuator.

[0048] In servo-operated mode, the locking valve operates in two ways: one is that oil flows from port b through the main valve port into port c; the other is that oil flows from port c through the main valve port into port b.

[0049] The working process of oil flowing from port b through the main valve port into port c is as follows:

[0050] When the pressure at port b is higher than that at port c, the ball plug 11 closes the pilot valve port of the main valve core 10 under the action of oil pressure; the main valve core 10 opens the main valve core port under the action of the oil pressure difference on both sides, connecting the oil circuits on both sides.

[0051] The working process of oil flowing from port c through the main valve port into port b is as follows:

[0052] When the pressure at port c is higher than that at port b and the electromagnet is energized, the pilot valve core 6 moves upward under the combined action of the electromagnet 2 and the pilot spring 4, opening the pilot valve port. The oil at port c communicates with port b through the main valve throttle orifice and the pilot valve port. At the same time, under the action of the high-pressure oil in the main oil circuit at the pump high-pressure outlet on the other side of port a, the hydraulic pilot valve core 13 moves upward to the limit position. Under the combined action of the pressure difference between the oil on both sides and the supporting force of the hydraulic pilot valve core 13, the main valve core 10 opens the main valve core port, connecting the oil circuits on both sides. When the electromagnet fails and loses power, the pilot valve port closes, and the main valve core 10 opens the main valve core port under the combined action of the pre-tightening force of the pilot spring 4 and the supporting force of the hydraulic pilot valve core 13, connecting the oil circuits on both sides.

[0053] In terms of the main valve port sealing design, a double-cone sealing structure is adopted, such as... Figure 2 As shown, when the first sealing surface wears more than a certain amount, the main valve core 10 enters the second sealing surface under the action of the pilot spring 4, ensuring the sealing effect of the main valve core in the locked working mode.

[0054] This invention employs a locking valve scheme that combines the energization of an electromagnet to engage the pilot valve core with the active action of high-pressure hydraulic fluid on the pilot valve core. The electromagnet-controlled pilot valve core, the hydraulically controlled valve core, and the main valve core are coaxially arranged and installed in the same valve sleeve. The electromagnet and high-pressure hydraulic fluid control the opening of a single main valve core, thus ensuring both the valve's locking function and the ability to open the valve using the working pressure of the actuation system in the event of electromagnet power failure. This redundancy in the locking valve's opening method ensures reliable locking and opening of the valve.

[0055] Meanwhile, the valve core seal adopts a double conical structure and a spring is set in the main valve core. When the valve's electromagnet is de-energized and there is no high-pressure oil, the spring can quickly push the main valve core to close the valve port and lock the oil circuit. When the first conical sealing surface wears and fails, the main valve core automatically compensates and moves to the position of the second sealing ring under the action of the spring, ensuring the sealing reliability of the locking function.

[0056] 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 possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An electro-hydraulic dual-redundant control locking valve for an electrostatic servo system, characterized in that: Includes locking screw (1), electromagnet (2), magnetic core tube (3), pilot spring (4), armature (5), pilot valve core (6), support spring (7), spring seat (8), valve sleeve (9), main valve core (10), ball plug (11), nut (12), hydraulic pilot valve core (13), and limit nut (14); Among them, the magnetic core tube (3) is set vertically in the axial direction; the electromagnet (2) is fitted on the top outer wall of the magnetic core tube (3); the side wall of the magnetic core tube (3) is provided with a stepped outer circle to limit the bottom of the electromagnet (2); the top of the electromagnet (2) and the magnetic core tube (3) are located on the same plane; the locking screw (1) is set on the top of the electromagnet (2) and the magnetic core tube (3); the electromagnet (2) is fixed by the threaded engagement of the locking screw (1) with the magnetic core tube (3); a columnar groove is provided at the center of the bottom of the magnetic core tube (3); the armature (5) is coaxially installed in the columnar groove; The main valve core (10) is set vertically, and an opening is provided at the bottom of the main valve core (10); the ball plug (11) is installed in the inner cavity of the main valve core (10), and the opening at the bottom of the main valve core (10) is sealed by the nut (12); the main valve core (10), the ball plug (11), and the nut (12) form the main valve core assembly; The top of the armature (5) is provided with a spring cavity; the pilot spring (4) is installed in the spring cavity; the bottom of the armature (5) is provided with a cylindrical inner hole; the pilot valve core (6) extends coaxially from bottom to top into the cylindrical inner hole of the armature (5); the spring seat (8) is fitted on the outer wall of the pilot valve core (6); the support spring (7) is fitted on the outer wall of the pilot valve core (6), and the top of the support spring (7) contacts the lower surface of the head end of the pilot valve core (6); the bottom of the support spring (7) contacts the spring seat (8); the pilot spring (4), armature (5), pilot valve core (6), support spring (7), and spring seat (8) constitute the pilot valve core assembly; The valve sleeve (9) is a cylindrical structure placed vertically in the axial direction; the main valve core assembly is first coaxially installed into the inner cavity of the valve sleeve (9); the pilot valve core assembly is assembled above the main valve core assembly, and the pilot valve core assembly is connected to the valve sleeve (9) through the external thread of the magnetic core tube (3). The hydraulic pilot valve core (13) is installed in the lower inner hole of the valve sleeve (9) and is limited by the limit nut (14).

2. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 1, characterized in that: The outer wall of the valve sleeve (9) is provided with oil port a, 4 oil ports b, and 4 oil ports c; Oil port a is located at the bottom axial end of the valve sleeve (9); four oil ports b are evenly distributed circumferentially on the side wall of the valve sleeve (9) and are located at the corresponding position of the hydraulic pilot valve core (13); four oil ports c are evenly distributed circumferentially on the side wall of the valve sleeve (9) and are located at the corresponding position of the main valve core (10).

3. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 2, characterized in that: It also includes a first sealing ring (15), a second sealing ring (16), a third sealing ring (17), a fourth sealing ring (18), and a fifth sealing ring (19); The first sealing ring (15) is located between the bottom outer wall of the hydraulic pilot valve core (13) and the valve sleeve (9); the second sealing ring (16) is located on the outer wall of the valve sleeve (9) and below the oil port b; the third sealing ring (17) is located on the outer wall of the valve sleeve (9) and between the oil port b and the oil port c; the fourth sealing ring (18) is located on the outer wall of the valve sleeve (9) and above the oil port c; and the fifth sealing ring (19) is located between the bottom outer wall of the magnetic core tube (3) and the inner wall of the valve sleeve (9).

4. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 3, characterized in that: The inner cavity of the valve sleeve (9) is separated from the outside by the fourth sealing ring (18) and the fifth sealing ring (19).

5. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 3, characterized in that: The locking valve is installed on one side of the main oil line of the external electrostatic servo actuator, that is, the high pressure port of the external motor pump is connected to the oil chamber of the actuator; the oil port b of the locking valve is connected to the high pressure oil port of the motor pump; the oil port c is connected to the oil chamber of the actuator; and the pilot oil port a is connected to the main oil line of the high pressure outlet of the pump on the other side.

6. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 3, characterized in that: The operating modes of the locking valve include locking mode and servo actuation mode.

7. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 6, characterized in that: In the locking mode, the locking valve operates as follows: There is no high-pressure oil at port a, and the electromagnet is de-energized. The pilot valve core (6) closes the pilot valve port under the action of the pilot spring (4). The oil cavity formed between the main valve core (10), the magnetic core tube (3), and the valve sleeve (9) is connected to port c through the side throttle hole of the main valve core (10). The main valve core (10) closes the main valve port under the action of the pilot valve core (6) and the pilot spring (4). When the pressure at port c is higher than the pressure at port b, the main valve core (10) closes the main valve port under the action of the pressure difference between the two sides of the oil, cuts off the oil circuits on both sides, that is, closes the main oil circuit on one side of the servo actuator.

8. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 6, characterized in that: In servo-operated mode, the locking valve operates in two ways: one is that oil flows from port b through the main valve port into port c; the other is that oil flows from port c through the main valve port into port b.

9. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 8, characterized in that: The working process of oil flowing from port b through the main valve port into port c is as follows: When the pressure at oil port b is higher than that at oil port c, the ball plug (11) closes the pilot valve port of the main valve core (10) under the action of oil pressure; the main valve core (10) opens the main valve core port under the action of the oil pressure difference on both sides, connecting the oil circuits on both sides. The working process of oil flowing from port c through the main valve port into port b is as follows: When the pressure at port c is higher than that at port b and the electromagnet is energized, the pilot valve core (6) moves upward and the pilot valve port opens under the combined action of the electromagnet (2) and the pilot spring (4); the oil at port c communicates with port b through the main valve throttle orifice and the pilot valve port; at the same time, under the action of the high pressure oil in the main oil circuit of the pump high pressure outlet on the other side of port a, the hydraulic pilot valve core (13) moves upward to the limit; under the combined action of the pressure difference between the oil on both sides and the supporting force of the hydraulic pilot valve core (13), the main valve core (10) opens the main valve core port and connects the oil circuits on both sides; when the electromagnet fails and loses power, the pilot valve port closes, and the main valve core (10) opens the main valve core port and connects the oil circuits on both sides under the combined action of the pre-tightening force of the pilot spring (4) and the supporting force of the hydraulic pilot valve core (13).

10. The electro-hydraulic dual-redundant control locking valve for an electrostatic servo system according to claim 9, characterized in that: In terms of the main valve port sealing design, a double cone sealing structure is adopted; when the first sealing surface wears more than a certain amount, the main valve core (10) enters the second sealing surface under the action of the pilot spring (4) to ensure the sealing effect of the main valve core in the locked working mode.

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