Dual-redundancy electro-hydraulic actuator with independent control and anti-death function

Abstract

The application discloses a double-redundancy electro-hydraulic actuator with independent control and anti-die function, and relates to the technical field of double-stage electro-hydraulic actuators. The double-stage cylinder comprises an outer cylinder body, an inner piston cylinder and an inner piston rod which are sequentially sleeved and connected in an extending and retracting mode from outside to inside. The outer cylinder body is provided with a first-stage extension pump liquid inlet and a first-stage contraction pump liquid inlet, and the inner piston cylinder is provided with a second-stage extension pump liquid inlet and a second-stage contraction pump liquid inlet. A three-position eight-way reversing valve is provided with a main position with four-in and four-out and two auxiliary positions with two-in and four-out. The control system comprises two independent pump systems. The inlet and outlet oil channels of the two pump systems are connected with four passages of the main position of the three-position eight-way reversing valve, and are communicated with the first-stage extension pump liquid inlet and the first-stage contraction pump liquid inlet and the second-stage extension pump liquid inlet and the second-stage contraction pump liquid inlet, so that the two pump systems can independently control the double-stage extension and retraction of the double-stage cylinder. The application can realize unified control of the double-stage cylinder under failure.

Description

Technical Field

[0001] This invention relates to the field of dual-stage electro-hydraulic actuator technology, and more specifically to a dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions. Background Technology

[0002] Two-stage electro-hydraulic actuators (EHAs) require in-house design and integrated manufacturing. Due to the long stroke and limited installation space of EHAs, special design of the hydraulic cylinder is necessary, employing a double-acting, asymmetric, single-rod two-stage hydraulic cylinder. Its characteristics include a long stroke and a short retracted length, achieving a longer stroke than a single-stage hydraulic cylinder within a given space. It is suitable for equipment with limited installation space but requiring a long stroke, and is widely used in space-constrained applications. However, for oscillating motors, the requirements for stroke control and stiffness are higher. Unlike ordinary two-stage hydraulic cylinders, it requires a servo-type, bidirectionally controllable two-stage cylinder.

[0003] When using a servo-controlled, bidirectional, two-stage hydraulic cylinder, each stage can be controlled independently, which places new demands on the control system. Research reveals that existing two-stage hydraulic cylinders all employ a unified control system; no cylinders capable of independently extending or retracting each stage have been developed. Furthermore, such cylinders play a crucial role in the development and application of two-stage electro-hydraulic actuators. Therefore, given the critical importance of controlling two-stage hydraulic cylinders, further research is needed to develop their control systems.

[0004] Therefore, how to provide a dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, aiming to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, comprising:

[0008] A two-stage cylinder, comprising an outer cylinder body, an inner piston cylinder, and an inner piston rod that are sequentially and telescopically connected from the outside in; the outer cylinder body has a first-stage elongation pump port and a first-stage contraction pump port, and the inner piston cylinder has a second-stage elongation pump port and a second-stage contraction pump port;

[0009] A three-position eight-way directional valve, wherein the three-position eight-way directional valve has a main position with four inlets and four outlets, and two auxiliary positions with two inlets and four outlets;

[0010] The control system includes two independent pump systems. The inlet and outlet oil passages of the two pump systems are respectively connected to the four passages of the main position of the three-position eight-way directional valve, and are respectively connected to the liquid port of the first-stage extension pump and the liquid port of the first-stage contraction pump, as well as the liquid port of the second-stage extension pump and the liquid port of the second-stage contraction pump, so that the two pump systems can independently control the two-stage extension and retraction of the two-stage cylinder.

[0011] Through the above technical solution, the present invention uses two pump systems to control the two-stage telescopic structure of the two-stage cylinder separately. The two-stage cylinder can be controlled independently by the two pump systems. When one pump system fails, the other pump system is switched in conjunction with the three-position eight-way reversing valve, which can achieve unified control under fault conditions. The present invention can meet the high requirements of the swing engine for stroke control and stiffness, and plays a key role in the development and use of the two-stage electro-hydraulic actuator.

[0012] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, the two two-input four-output sub-positions are respectively used to switch positions when either of the two pump systems fails, thereby uniformly controlling the two-stage extension and retraction of the two-stage cylinder.

[0013] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, both pump systems are bidirectional pump systems that use bidirectional pump control for oil inlet and outlet switching. Utilizing the advantages of bidirectional pump systems—convenient oil switching, small oil tank, and compact structure—a dual-stage electro-hydraulic actuator with similar redundancy is formed.

[0014] Preferably, in the aforementioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, the two pump systems respectively employ a bidirectional pump system with bidirectional pump control for oil inlet and outlet switching, and a unidirectional pump system with proportional directional valve control for oil inlet and outlet switching. The unidirectional pump system has lower requirements for the pump itself but higher requirements for the proportional directional valve, resulting in less pump impact and protecting the pump's service life. The bidirectional pump system, on the other hand, has higher requirements for the pump but a smaller oil tank and a more compact structure. The two systems can complement each other, preventing both pump systems from experiencing the same failure simultaneously.

[0015] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, the bidirectional pump system includes a bidirectional pump. The two pump / suction ports of the bidirectional pump are respectively connected to a low-volume supply / return oil circuit and a high-volume supply / return oil circuit. A replenishment oil circuit is connected between the low-volume supply / return oil circuit and the high-volume supply / return oil circuit. Two first one-way valves in opposite directions are installed on the replenishment oil circuit. An oil tank branch is provided between the two first one-way valves. An oil tank is connected to the oil tank branch. The oil in the oil tank can flow to the low-volume supply / return oil circuit and the high-volume supply / return oil circuit respectively through the two first one-way valves. An oil storage circuit is connected between the oil tank branch and the high-volume supply / return oil circuit. An electromagnetic switch valve is installed on the oil storage circuit.

[0016] The bidirectional pump system adds an oil storage circuit and a solenoid valve to the original pump system structure. Since it is designed for asymmetrical hydraulic cylinders, that is, the two chambers are different in size, the solenoid valve can control the excess oil in the extended chamber to flow back to the oil tank when retracting, thus coordinating the problem of inconsistent oil supply and return of the bidirectional pump, making the bidirectional pump system have a smaller design volume.

[0017] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, an oil drain pipe is connected between the oil tank branch and the oil drain port of the bidirectional pump. A second check valve and a filter are installed on the oil drain pipe. The drain oil from the bidirectional pump flows to the oil tank through the second check valve. The filter is located between the second check valve and the bidirectional pump.

[0018] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, there are multiple safety control oil circuits between the low-volume supply / return oil circuit and the high-volume supply / return oil circuit, and relief valves and mode valves are respectively installed on the multiple safety control oil circuits.

[0019] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, the sliding end of the inner piston cylinder that cooperates with the outer cylinder body is connected to a first piston head, and the sliding end of the inner piston rod that cooperates with the inner piston cylinder is connected to a second piston head.

[0020] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, a primary piston chamber is formed on the inner side of the outer cylinder body, and the two pump / return ports at both ends of the outer cylinder body are a primary extension pump port and a primary contraction pump port, respectively. The first piston head divides the primary piston chamber into two chambers corresponding to the primary extension pump port and the primary contraction pump port, respectively.

[0021] Preferably, in the above-mentioned dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function, a secondary piston chamber is formed inside the inner piston cylinder. The two pump / return ports at the exposed end of the inner piston cylinder are a secondary extension pump port and a secondary contraction pump port, respectively. The second piston head divides the secondary piston chamber into two chambers corresponding to the secondary extension pump port and the secondary contraction pump port, respectively. A flow channel is provided inside the side wall of the inner piston cylinder, and the flow channel connects the secondary extension pump port and the secondary piston chamber located at one end of the inner piston cylinder inside the outer cylinder. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 The attached figure is a schematic diagram of the oil circuit of a two-stage electro-hydraulic actuator with similar redundancy according to Embodiment 1 of the present invention;

[0024] Figure 2 The attached figure is a schematic diagram of the oil circuit for the switching sub-position of a two-stage electro-hydraulic actuator with similar redundancy in Embodiment 1 provided by the present invention;

[0025] Figure 3 The attached figure is a schematic diagram of the oil circuit for switching another sub-position of a two-stage electro-hydraulic actuator with similar redundancy in Embodiment 1 of the present invention.

[0026] Figure 4 The attached figure is a schematic diagram of the oil circuit of a two-stage electro-hydraulic actuator with non-similar redundancy according to Embodiment 2 of the present invention;

[0027] Figure 5 The attached figure is a schematic diagram of the oil circuit for the switching sub-position of a two-stage electro-hydraulic actuator with non-similar redundancy provided in Embodiment 2 of the present invention;

[0028] Figure 6 The attached figure is a schematic diagram of the oil circuit for switching another sub-position of a two-stage electro-hydraulic actuator with non-similar redundancy provided in Embodiment 2 of the present invention.

[0029] Figure 7 The attached figure is a schematic diagram of the hydraulic circuit of the bidirectional pump system provided by the present invention;

[0030] Figure 8 The attached figure is a schematic diagram of the hydraulic circuit of the unidirectional pump system provided by the present invention;

[0031] Figure 9The attached figure is a schematic diagram of the structure of the two-stage cylinder of Embodiment 3 provided by the present invention;

[0032] Figure 10 The attached figure is a cross-sectional view of the two-stage cylinder of Embodiment 3 provided by the present invention;

[0033] Figure 11 The attached figure is a cross-sectional view of the two-stage cylinder of Embodiment 3 provided by the present invention from another angle;

[0034] Figure 12 The attached figure is provided by the present invention. Figure 10 A magnified view of part A in the middle;

[0035] Figure 13 The attached figure is provided by the present invention. Figure 10 A magnified view of part B in the middle;

[0036] Figure 14 The attached figure is provided by the present invention. Figure 10 A magnified view of part C in the middle;

[0037] Figure 15 The attached figure is provided by the present invention. Figure 10 A magnified view of part D in the middle;

[0038] Figure 16 The attached figure is provided by the present invention. Figure 10 A magnified view of part E in the middle;

[0039] Figure 17 The attached figure is provided by the present invention. Figure 10 A magnified view of a local area F;

[0040] Figure 18 The attached figure is provided by the present invention. Figure 10 A magnified view of a local area G in the middle;

[0041] Figure 19 The attached figure is provided by the present invention. Figure 10 A magnified view of a local area H in the middle.

[0042] in:

[0043] 1-Two-stage cylinder;

[0044] 10 - Outer cylinder block;

[0045] 100-Outer cylinder; 1000-First stage piston chamber; 1001-First flange; 101-Outer cylinder fixed end cap; 1010-First stage extension pump port; 1011-First insertion section; 1012-First annular groove; 1013-First O-ring seal; 102-Outer cylinder telescopic end cap; 1020-First stage contraction pump port; 1021-First stage piston port; 1022-Second insertion section; 1023-Second annular groove; 1024-Second O-ring seal; 1025-Third annular groove; 1026-First shaft combination seal; 1027-First rectangular seal; 1028-First dustproof seal; 103-First bolt group;

[0046] 20-Internal piston cylinder;

[0047] 200-Inner cylinder; 2000-Secondary piston chamber; 2001-Flow channel; 2002-Second flange; 201-First piston head; 2010-Third insertion section; 2011-Fourth annular groove; 2012-Third O-ring seal; 2013-Fifth annular groove; 2014-First hole combination seal; 2015-Second rectangular seal; 202-Inner cylinder telescopic end cap; 2020-Secondary extension pump port; 2021-Secondary contraction pump port; 2022-Secondary piston port; 2023-Fourth insertion section; 2024-Sixth annular groove; 2025-Fourth O-ring seal; 2026-Seventh annular groove; 2027-Second shaft combination seal; 2028-Third rectangular seal; 2029-Second sealing dust ring; 203-Second bolt group; 204-Third bolt group;

[0048] 30 - Inner piston rod;

[0049] 300-Second piston head; 3000-Eighth annular groove; 3001-Fifth O-ring seal; 3002-Ninth annular groove; 3003-Combination seal for second hole; 3004-Fourth rectangular seal; 301-Tightening nut;

[0050] 40 - Three-position eight-way directional valve;

[0051] 400 - Major; 401 - Minor;

[0052] 50-Bidirectional pump system;

[0053] 500-Bidirectional pump; 501-Low-flow supply / return oil circuit; 502-High-flow supply / return oil circuit; 503-Replenishment oil circuit; 504-First check valve; 505-Tank branch; 506-Tank; 507-Storage circuit; 508-Solenoid switch valve; 509-Drain line; 510-Second check valve; 511-Filter; 512-Safety control circuit; 513-Relief valve; 514-Mode valve;

[0054] 60 - One-way pump system;

[0055] 600 - Proportional directional valve; 601 - Safety valve. Detailed Implementation

[0056] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] See appendix Figure 1 This invention discloses a dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, comprising:

[0058] A two-stage cylinder 1 includes an outer cylinder body 10, an inner piston cylinder 20, and an inner piston rod 30 that are sequentially sleeved and telescopically connected from the outside to the inside; the outer cylinder body 10 has a first-stage extension pump port 1010 and a first-stage contraction pump port 1020, and the inner piston cylinder 20 has a second-stage extension pump port 2020 and a second-stage contraction pump port 2021;

[0059] A three-position eight-way directional valve 40, wherein the three-position eight-way directional valve 40 has a main position 400 with four inlets and four outlets, and two secondary positions 401 with two inlets and four outlets;

[0060] The control system includes two independent pump systems. The inlet and outlet oil passages of the two pump systems are respectively connected to the four passages of the main position 400 of the three-position eight-way directional valve 40, and are respectively connected to the liquid port 1010 of the first-stage extension pump and the liquid port 1020 of the first-stage contraction pump, as well as the liquid port 2021 of the second-stage extension pump and the liquid port 2021 of the second-stage contraction pump, so that the two pump systems can independently control the two-stage extension and retraction of the two-stage cylinder 1.

[0061] To further optimize the above technical solution, the two two-input four-output sub-positions 401 are used to switch positions accordingly when either of the two pump systems fails, thereby enabling unified control of the two-stage extension and retraction of the two-stage cylinder 1.

[0062] Example 1:

[0063] See appendix Figure 1 To be continued Figure 3 This invention discloses a two-stage electro-hydraulic actuator with similar redundancy, comprising:

[0064] The two-stage cylinder 1 includes an outer cylinder body 10, an inner piston cylinder 20, and an inner piston rod 30 that are sequentially sleeved and telescopically connected from the outside to the inside; the outer cylinder body 10 has a first-stage extension pump port 1010 and a first-stage contraction pump port 1020, and the inner piston cylinder 20 has a second-stage extension pump port 2020 and a second-stage contraction pump port 2021.

[0065] The three-position eight-way directional valve 40 has a main position 400 with four inlets and four outlets, and two auxiliary positions 401 with two inlets and four outlets.

[0066] Two sets of bidirectional pump systems 50 are provided. The inlet and outlet oil passages of the two sets of bidirectional pump systems 50 are respectively connected to the four passages of the main position 400 of the three-position eight-way directional valve 40, and are respectively connected to the first-stage extension pump port 1010 and the first-stage contraction pump port 1020, as well as the second-stage extension pump port 2020 and the second-stage contraction pump port 2021, so that the two bidirectional pump systems 20 can independently control the two-stage extension and retraction of the two-stage cylinder 1.

[0067] To further optimize the above technical solution, the two two-input four-output sub-positions 401 are used to switch positions accordingly when any bidirectional pump system 50 is damaged, thereby enabling unified control of the bi-stage extension and retraction of the two-stage cylinder 1.

[0068] To further optimize the above technical solution, the bidirectional pump system 50 controls the pump oil flow rate through bidirectional pump speed regulation.

[0069] The three-position eight-way directional valve 40 provided in this embodiment is as follows: Figure 1 As shown, it will not be repeated here. See Appendix. Figure 2 When the right-side bidirectional pump system 50 fails, the three-position eight-way directional valve 40 switches to the position shown in the attached diagram. Figure 2 As shown in the diagram, at this time, the bidirectional pump system 50 on the left side provides unified control over the bi-stage extension and retraction of the two-stage cylinder 1; see appendix. Figure 3 When the left-side bidirectional pump system 50 fails, the three-position eight-way directional valve 40 switches to the position shown in the attached diagram. Figure 3 As shown in the sub-position 401, at this time, the bidirectional pump system 50 on the right side provides unified control over the bi-stage extension and retraction of the bi-stage cylinder 1.

[0070] In this embodiment, see Appendix Figure 7The bidirectional circulation pump system includes a bidirectional pump 500. The two pump / suction ports of the bidirectional pump 500 are respectively connected to a low-volume supply / return oil circuit 501 and a high-volume supply / return oil circuit 502. A replenishment oil circuit 503 is connected between the low-volume supply / return oil circuit 501 and the high-volume supply / return oil circuit 502. Two first check valves 504 with opposite directions are installed on the replenishment oil circuit 503. An oil tank branch 505 is connected between the two first check valves 504. An oil tank 506 is connected to the oil tank branch 505. The oil in the oil tank 506 can flow to the low-volume supply / return oil circuit 501 and the high-volume supply / return oil circuit 502 through the two first check valves 504 respectively. An oil storage circuit 507 is connected between the oil tank branch 505 and the high-volume supply / return oil circuit 502. An electromagnetic switch valve 508 is installed on the oil storage circuit 507.

[0071] To further optimize the above technical solution, an oil drain pipe 509 is connected between the oil tank branch 505 and the oil drain port of the bidirectional pump 500. A second check valve 510 is installed on the oil drain pipe 509, and the drained oil from the bidirectional pump 500 flows to the oil tank 506 through the second check valve 510.

[0072] To further optimize the above technical solution, a filter 511 is installed on the oil drain line 509. The filter 511 is located between the second check valve 510 and the bidirectional pump 500.

[0073] To further optimize the above technical solution, multiple safety control oil circuits 512 are provided between the low-volume supply / return oil circuit 501 and the high-volume supply / return oil circuit 502, and relief valves 513 and mode valves 514 are respectively installed on the multiple safety control oil circuits 512.

[0074] To further optimize the above technical solution, the number of overflow valves 513 is two, and the overflow directions of the two overflow valves 513 are opposite.

[0075] To further optimize the above technical solution, oil tank 506 is a pressurized oil tank.

[0076] To further optimize the above technical solution, the bidirectional pump 500 is driven by a motor.

[0077] To further optimize the above technical solution, the oil supply and return volume of the low-volume supply / return oil circuit 501 is less than that of the high-volume supply / return oil circuit 502.

[0078] To further optimize the above technical solution, the electromagnetic switch valve 508 is opened when oil returns from the high-volume supply / return oil circuit 502.

[0079] Example 2:

[0080] See appendix Figure 4 This invention discloses a two-stage electro-hydraulic actuator with dissimilar redundancy, comprising:

[0081] The two-stage cylinder 1 includes an outer cylinder body 10, an inner piston cylinder 20, and an inner piston rod 30 that are sequentially sleeved and telescopically connected from the outside to the inside; the outer cylinder body 10 has a first-stage extension pump port 1010 and a first-stage contraction pump port 1020, and the inner piston cylinder 20 has a second-stage extension pump port 2020 and a second-stage contraction pump port 2021.

[0082] The three-position eight-way directional valve 40 has a main position 400 with four inlets and four outlets, and two auxiliary positions 401 with two inlets and four outlets.

[0083] Control system; The control system includes a bidirectional pump system 50 and a unidirectional pump system 60. The inlet and outlet oil passages of the bidirectional pump system 50 and the unidirectional pump system 60 are respectively connected to the four passages of the main position 400 of the three-position eight-way directional valve 40, and are respectively connected to the first-stage extension pump port 1010 and the first-stage contraction pump port 1020, as well as the second-stage extension pump port 2020 and the second-stage contraction pump port 2021, so that the bidirectional pump system 50 and the unidirectional pump system 60 can independently control the two-stage extension and retraction of the two-stage cylinder 1.

[0084] The three-position eight-way directional valve 40 provided in this embodiment is as follows: Figure 4 As shown, it will not be repeated here. See Appendix. Figure 5 When the right-side bidirectional pump system 50 fails, the three-position eight-way directional valve 40 switches to the position shown in the attached diagram. Figure 5 As shown in the diagram, at this time, the two-stage extension and retraction of the two-stage cylinder 1 is uniformly controlled by the unidirectional pump system 60 on the left; see appendix. Figure 6 When the left-side one-way pump system 60 fails, the three-position eight-way directional valve 40 switches to the position shown in the attached diagram. Figure 6 As shown in the sub-position 401, at this time, the bidirectional pump system 50 on the right side provides unified control over the bi-stage extension and retraction of the bi-stage cylinder 1.

[0085] The specific structure of the bidirectional pump system 50 provided in this embodiment is the same as that in Embodiment 1, and will not be described again here.

[0086] The specific structure of the unidirectional pump system 60 provided in this embodiment is as follows: Figure 8 The diagram shows a conventional structure driven by a unidirectional pump. It uses a proportional directional valve 600 to switch the oil pipeline, thus solving the flow mismatch problem. A safety valve 601 is also used to prevent safety hazards caused by excessive pump pressure; details will not be elaborated further.

[0087] Example 3:

[0088] See appendix Figure 9 To be continued Figure 11 The two-stage cylinder 1 structure provided in this embodiment of the invention specifically includes:

[0089] The outer cylinder 10 has a first-stage piston chamber 1000 and a first-stage piston port 1021 communicating with the first-stage piston chamber 1000 at one end. The side walls at both ends of the outer cylinder 10 have a first-stage elongation pump port 1010 and a first-stage contraction pump port 1020 communicating with the first-stage piston chamber 1000.

[0090] An inner piston cylinder 20 is coaxially sleeved inside the outer cylinder body 10, and its outer side wall is slidably connected to the first-stage piston port 1021. A first piston head 201 is connected to the end of the inner piston cylinder 20 located inside the first-stage piston chamber 1000. The side wall of the first piston head 201 is slidably connected to the side wall of the first-stage piston chamber 1000, dividing the first-stage piston chamber 1000 into two chambers corresponding to the first-stage extension pump port 1010 and the first-stage contraction pump port 1020, respectively. A second-stage piston chamber 2000 is formed inside the inner piston cylinder 20. The end of the first-stage piston chamber 1000 has a second-stage piston port 2022 that communicates with the second-stage piston chamber 2000; the inner piston cylinder 20 has a second-stage elongation pump port 2020 and a second-stage contraction pump port 2021 formed on the side wall of one end of the inner piston cylinder 20 located outside the first-stage piston chamber 1000. The second-stage elongation pump port 2020 communicates with the flow channel 2001 opened inside the side wall of the inner piston cylinder 20 and communicates with the second-stage piston chamber 2000 located at one end of the inner piston cylinder 20 located inside the first-stage piston chamber 1000. The second-stage contraction pump port 2021 communicates with the second-stage piston chamber 2000 located at one end of the inner piston cylinder 20 located outside the first-stage piston chamber 1000.

[0091] An inner piston rod 30 is coaxially sleeved inside the inner piston cylinder 20, and the outer wall of the inner piston rod 30 is in a sealed sliding connection with the secondary piston port 2022. The end of the inner piston rod 30 located inside the secondary piston chamber 2000 is connected to a second piston head 300. The side wall of the second piston head 300 is in a sealed sliding connection with the side wall of the secondary piston chamber 2000. The second piston head 300 divides the secondary piston chamber 2000 into two chambers corresponding to the secondary extension pump port 2020 and the secondary contraction pump port 2021, respectively.

[0092] To further optimize the above technical solution, the outer cylinder body 10 includes an outer cylinder barrel 100, an outer cylinder fixed end cover 101, and an outer cylinder telescopic end cover 102; both ends of the outer cylinder barrel 100 have a first flange 1001, the outer cylinder fixed end cover 101 and the outer cylinder telescopic end cover 102 are respectively connected to the two first flanges 1001 by a first bolt group 103, a first-stage extension pump port 1010 is opened on the side wall of the outer cylinder fixed end cover 101, and a first-stage contraction pump port 1020 is opened on the side wall of the outer cylinder telescopic end cover 102.

[0093] See appendix Figure 12The connection end of the outer cylinder fixed end cover 101 and the outer cylinder barrel 100 has a first insertion section 1011 that inserts into the inner side of the outer cylinder barrel 100. The outer side wall of the first insertion section 1011 is provided with a first annular groove 1012, and a first O-ring seal 1013 is embedded in the first annular groove 1012.

[0094] See appendix Figure 13 and attached Figure 14 The outer cylinder telescopic end cap 102 has a second insertion section 1022 that inserts into the inner side of the outer cylinder 100 at the connection end with the outer cylinder 100. The outer side wall of the second insertion section 1022 has a second annular groove 1023, and a second O-ring seal 1024 is embedded in the second annular groove 1023. The end of the outer cylinder telescopic end cap 102 away from the outer cylinder 100 is a first-stage piston port 1021. The inner side wall of the first-stage piston port 1021 has multiple third annular grooves 1025, and a first shaft combination seal 1026, a first rectangular seal 1027, and a first sealing dustproof ring 1028 are embedded in the multiple third annular grooves 1025.

[0095] To further optimize the above technical solution, the inner piston cylinder 20 also includes an inner cylinder barrel 200 and an inner cylinder telescopic end cap 202; the end of the inner cylinder barrel 200 located inside the first-stage piston chamber 1000 has a second flange 2002, the first piston head 201 is connected to the second flange 2002 by a second bolt group 203, and the inner cylinder telescopic end cap 202 is connected to the telescopic end of the inner cylinder barrel 200 by a third bolt group 204; the flow channel 2001 is opened on the side wall of the inner cylinder barrel 200, and the secondary extension pump port 2020 and the secondary contraction pump port 2021 are both opened on the side wall of the inner cylinder telescopic end cap 202.

[0096] See appendix Figure 15 and attached Figure 16 The first piston head 201 has a third insertion section 2010 that inserts into the inner side of the inner cylinder 200 at the connection end with the inner cylinder 200. The outer side wall of the third insertion section 2010 is provided with a fourth annular groove 2011, and a third O-ring seal 2012 is embedded in the fourth annular groove 2011. The outer side wall of the first piston head 201 is provided with a plurality of fifth annular grooves 2013, and a first hole combination seal 2014 and a second rectangular seal 2015 are embedded in the plurality of fifth annular grooves 2013.

[0097] See appendix Figure 17 and attached Figure 18The inner cylinder telescopic end cap 202 and the inner cylinder barrel 200 have a fourth insertion section 2023 that inserts into the inner side of the inner cylinder barrel 200. The outer side wall of the fourth insertion section 2023 is provided with a sixth annular groove 2024. A fourth O-ring seal 2025 is embedded in the sixth annular groove 2024. The end of the inner cylinder telescopic end cap 202 away from the inner cylinder barrel 200 is a secondary piston port 2022. The inner side wall of the secondary piston port 2022 has multiple seventh annular grooves 2026. A second shaft combination seal 2027, a third rectangular seal 2028 and a second sealing dustproof ring 2029 are embedded in the multiple seventh annular grooves 2026.

[0098] To further optimize the above technical solution, the second piston head 300 is sleeved on the end of the inner piston rod 30 located inside the secondary piston chamber 2000, and is locked by the top nut 301.

[0099] See appendix Figure 19 The inner ring of the second piston head 300 is provided with an eighth annular groove 3000, and a fifth O-ring seal 3001 is embedded in the eighth annular groove 3000. The outer wall of the second piston head 300 is provided with multiple ninth annular grooves 3002, and a second hole combination seal 3003 and a fourth rectangular seal 3004 are embedded in the multiple ninth annular grooves 3002.

[0100] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0101] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions, characterized in that, include: A two-stage cylinder, comprising an outer cylinder body, an inner piston cylinder, and an inner piston rod that are sequentially and telescopically connected from the outside in; the outer cylinder body has a first-stage elongation pump port and a first-stage contraction pump port, and the inner piston cylinder has a second-stage elongation pump port and a second-stage contraction pump port; A three-position eight-way directional valve, wherein the three-position eight-way directional valve has a main position with four inlets and four outlets, and two auxiliary positions with two inlets and four outlets; Control system; the control system includes two independent pump systems, the inlet and outlet oil passages of the two pump systems are respectively connected to the four passages of the main position of the three-position eight-way directional valve, and respectively connected to the liquid port of the first-stage extension pump and the liquid port of the first-stage contraction pump, as well as the liquid port of the second-stage extension pump and the liquid port of the second-stage contraction pump, so that one pump system can independently control the first-stage extension and retraction of the two-stage cylinder, and the other pump system can independently control the second-stage extension and retraction of the two-stage cylinder; When the pump system on the right side fails, the three-position eight-way directional valve switches to one of the auxiliary positions. At this time, the pump system on the left side controls the two-stage extension and retraction of the two-stage cylinder. When the pump system on the left side fails, the three-position eight-way directional valve switches to the other auxiliary position. At this time, the pump system on the right side controls the two-stage extension and retraction of the two-stage cylinder. The two pump systems are respectively a bidirectional pump system with bidirectional pump control for oil inlet and outlet switching, and a unidirectional pump system with proportional directional valve control for oil inlet and outlet switching.

2. The dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function according to claim 1, characterized in that, Both pump systems are bidirectional pump systems that use bidirectional pump control to switch between oil inlet and outlet.

3. The dual-redundant electro-hydraulic actuator with independent control and anti-necrosis function according to claim 1, characterized in that, The bidirectional pump system includes a bidirectional pump. The two pump / suction ports of the bidirectional pump are respectively connected to a low-volume supply / return oil circuit and a high-volume supply / return oil circuit. A replenishment oil circuit connects the low-volume supply / return oil circuit and the high-volume supply / return oil circuit. Two first-one-way valves in opposite directions are installed on the replenishment oil circuit. An oil tank branch is located between the two first-one-way valves and is connected to an oil tank. Oil in the oil tank can flow to the low-volume supply / return oil circuit and the high-volume supply / return oil circuit respectively through the two first-one-way valves. An oil storage circuit is connected between the oil tank branch and the high-volume supply / return oil circuit, and a solenoid valve is installed on the oil storage circuit.

4. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions according to claim 3, characterized in that, An oil drain pipe is connected between the oil tank branch and the drain port of the bidirectional pump. A second check valve and a filter are installed on the oil drain pipe. The drain oil from the bidirectional pump flows to the oil tank through the second check valve. The filter is located between the second check valve and the bidirectional pump.

5. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions according to claim 3, characterized in that, There are also multiple safety control oil circuits between the low-volume supply / return oil circuit and the high-volume supply / return oil circuit, and relief valves and mode valves are respectively installed on the multiple safety control oil circuits.

6. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions according to claim 1, characterized in that, The sliding end of the inner piston cylinder that mates with the outer cylinder is connected to a first piston head, and the sliding end of the inner piston rod that mates with the inner piston cylinder is connected to a second piston head.

7. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions according to claim 6, characterized in that, A primary piston chamber is formed inside the outer cylinder. The pump port and return port at both ends of the outer cylinder are respectively a primary extension pump port and a primary contraction pump port. The first piston head divides the primary piston chamber into two chambers corresponding to the primary extension pump port and the primary contraction pump port, respectively.

8. A dual-redundant electro-hydraulic actuator with independent control and anti-necrosis functions according to claim 6 or 7, characterized in that, The inner piston cylinder has a secondary piston chamber formed on its inner side. The pump port and return port at the exposed end of the inner piston cylinder are the secondary extension pump port and the secondary contraction pump port, respectively. The second piston head divides the secondary piston chamber into two chambers corresponding to the secondary extension pump port and the secondary contraction pump port, respectively. A flow channel is opened inside the side wall of the inner piston cylinder, and the flow channel connects the secondary extension pump port and the secondary piston chamber located at one end of the inner piston cylinder inside the outer cylinder.

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