All-electric dual-redundancy emergency retraction and extension electro-mechanical actuator

Abstract

The full electric dual-redundancy emergency receiver electric actuator is safe, reliable and has good fault tolerance. The following technical scheme is adopted: a piston cylinder assembly is provided with opposite symmetrical main motors on the free end, a vice motor which is a backup of the main motor, an output gear of the vice motor is engaged and assembled with an end gear of a lead screw sleeve cylinder in the piston cylinder assembly, a lead screw sleeve flange ring inserted into a ring hole in a piston head step is constrained on an end ring of a terminal bearing, a lead screw sleeve sleeve is fitted on a lead screw nut which makes telescopic movement in a movement cavity, the lead screw nut sleeve is inserted into a lead screw auxiliary part of the piston head along a bottom end fixed guide rail of an outer cylinder, the piston cylinder assembly is driven to make linear movement in a push-pull stroke in a step constraint movement cavity of the outer cylinder, the main motor drives the lead screw auxiliary part to engage the lead screw nut to rotate, or the vice motor drives the lead screw sleeve to engage the lead screw nut to rotate, and the piston cylinder assembly is driven to move in the EMA outer cylinder movement cavity, and two opposite independent dual-redundancy emergency receiving and releasing transmission chains are formed.

Description

Technical Field

[0001] This invention relates to a dual-redundant emergency retraction structure applied to an all-electric motor actuator; more specifically, this invention relates to an innovative structure for an all-electric dual-redundant emergency retraction actuator. Background Technology

[0002] Modern aircraft actuation systems primarily employ hydraulic actuation systems and some pneumatic auxiliary systems. Hydraulic actuation systems require a complex central hydraulic system and are prone to oil leakage, resulting in complex structures, numerous support devices, and difficult maintenance. While a single electromechanical actuator is not significantly heavier than a single hydraulic actuator, the overall weight can be greatly reduced by eliminating the associated hydraulic lines. Traditional hydraulic actuation systems must maintain a certain hydraulic pressure regardless of whether the actuator is operational, consuming corresponding power. Electromechanical actuators, on the other hand, only consume power during operation, thus offering higher efficiency. Recently developed all-electric transmission systems utilize hydraulic servo systems, which contribute significantly to system weight, hindering system integration and reducing reliability. Takeoff and landing are the most accident-prone phases for aircraft. During landing, electromechanical actuators and connecting cables are exposed outside the landing gear. When the aircraft lands, all kinetic energy is absorbed by the brake discs, generating substantial heat that can easily cause power line failures, leading to power outages. Replacing hydraulic actuators with electromechanical actuators is a crucial step in the development of all-electric and multi-electric aircraft. As aircraft evolve towards full electrification and usage requirements become increasingly stringent, the shortcomings of hydraulic landing gear systems are becoming more pronounced, negatively impacting the performance of small aircraft. Therefore, achieving fully electric landing gear deployment has been a key technical challenge in the development of all-electric aircraft. With the introduction of the concept of fully electric transmission systems, the electric actuator landing gear actuator cylinder mainly consists of a DC servo motor main drive unit, a pneumatic motor, a pneumatic clutch emergency drive unit, a locking mechanism, a piston cylinder, and related connecting parts, forming a mechanical device; a reducer, a synchronous belt, a ball screw transmission device, and a detection device (microswitches). The DC motor and pneumatic motor are connected via a pneumatic clutch, with the DC motor serving as the main power source and the pneumatic motor as the emergency power source. The locking mechanism is connected to the ball screw nut pair via screws, and the piston cylinder is connected to the locking mechanism via threads. Two microswitches are located at each end of the actuator cylinder to control motor speed and provide positioning signal feedback. Replacing hydraulic actuators with electromechanical actuators is a crucial step in the development of all-electric and multi-electric aircraft. Electromechanical actuators (EMAs) are critical components of flight control systems, and their reliability directly impacts aircraft flight safety. As linear motion actuators, EMAs are energy conversion devices used to achieve linear reciprocating motion or oscillating motion less than 360° in a working mechanism. Typically, an EMA consists of a driver, drive motor, reduction gearbox, ball screw, ball screw pair transmission components, detection feedback and load actuator outer cylinder assembly, piston cylinder assembly, self-locking assembly, detection feedback position detection element, and load. It indirectly or directly controls the target motion by controlling the operation of the actuator.

[0003] To improve the reliability of electromechanical actuation systems, existing technologies employ redundancy techniques in system design. One method to enhance the reliability of electromechanical actuation systems is to utilize redundancy structures. Currently, there are three redundancy schemes for electromechanical actuators researched domestically and internationally. The redundancy structures used by EMA are mainly divided into mechanical redundancy, electrical redundancy, and a hybrid redundancy combining electrical and mechanical redundancy. In the electrical redundancy structure, the motor system uses a single rotor with multiple windings mounted on a single stator. Torque magnetic integration is achieved between the windings, and each winding uses its own control circuit, forming a multi-channel control system. The mechanical redundancy structure connects multiple motors through gear transmission devices, with each motor using its own control circuit, forming a multi-channel control system. The rudder of a dual-redundant electromechanical actuator integrates the shafts of two motors through differential gears, forming a mechanically integrated dual-redundant electromechanical actuation system. Due to the imperfect symmetry between the two channels in a dual-redundant system and the influence of various factors such as power supply differences, load variations, and ambient temperature changes, current imbalances may occur in the two windings of the motor. Therefore, a "current contention" phenomenon exists in the operation of a dual-redundant electromechanical actuator system. A quadruple-redundant electromechanical actuator system consists of a digital controller, four power circuits, two dual-channel brushless DC motors, two brushless rotary transformers, and a differential gear forming a four-control-channel power transmission system. The differential gear outputs the two brushless DC motors after mechanical integration. When the redundant system operates in parallel, balancing techniques are used to address the deviations between channels. For redundant electromechanical actuators with torque-magnetically coupled dual-redundant windings, current balancing control is essential. However, simulations of parallel system operation demonstrate that when the voltage difference between the two power converters increases, severe current imbalances occur, potentially leading to a situation where one winding is in a motoring state while the other is in a generating state, causing severe motor overheating and endangering system safety. In applications with high safety and mission reliability requirements, such as electromechanical actuators used in aircraft landing gear retraction and extension, a safety margin for landing gear deployment is essential. Currently, there are two schemes for using electromechanical actuators to deploy and retract the landing gear: one involves the actuator piston cylinder extending to deploy the landing gear, and the other involves the piston cylinder retracting to deploy the landing gear. A common redundant design for electromechanical actuators uses a backup motor. When the main motor fails, the backup motor operates to deploy the piston cylinder in an emergency. However, this cannot solve the single-point failure problem of lead screw pair jamming, resulting in low mission reliability and poor practicality. To address the single-point failure problem of electromechanical actuator transmission components, existing conventional multi-stage electromechanical actuators employ a redundant transmission mechanism design. This redundancy design aims to improve the reliability of the landing gear braking system, but it still faces the problem of single-point failures such as lead screw pair jamming. To improve the reliability of servo actuation systems, existing technologies have proposed a dissimilar redundancy design scheme. Dissimilar redundancy actuation systems have two or more channels that are not completely identical in hardware or software, operating synchronously.For example, the processor, controller software, and electromechanical components of a servo controller can all employ dissimilar redundancy design. Parallel redundant actuators suffer from signal mismatch issues, thus requiring balancing methods. Common methods include mechanical force integration, hydraulic force integration, and flux integration. Mechanical force integration actuators suffer from force contention; electromechanical actuators operating in a force-integrated manner can lead to asynchrony. Balancing techniques or decoupling control are needed to mitigate or eliminate force contention. Hydraulic force integration adds the output forces of the two actuators as the output, eliminating force contention, and is therefore frequently used in similar redundancy actuators. However, because the dynamic response of electro-hydraulic actuation systems is slower than that of electro-hydraulic servo actuators, if hydraulic force integration is used, the output force difference acting on the actuator piston cylinder can be significant in a short time. Furthermore, centralized energy hydraulic actuation systems suffer from disadvantages such as large weight, low efficiency, and high maintenance costs. If dissimilar hybrid actuators are used in multi-electric aircraft, the dissimilar redundancy configuration leads to force contention in the hybrid redundancy actuator system. Since the two channels of a dual-redundant system cannot be perfectly symmetrical, various factors such as power supply differences, load changes, and ambient temperature variations can cause current imbalances in the two sets of motor windings. Therefore, a "current contention" phenomenon exists during the operation of a dual-redundant electromechanical actuator system. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies and meets the high reliability requirements of EMA (Electrical Equipment Manufacturer). It employs redundancy technology to provide a simple, safe, reliable, and fault-tolerant all-electric dual-redundant emergency retraction electromechanical actuator solution that, under power supply, enables a fully electric, dual-redundant emergency retraction piston cylinder. This effectively solves the problem of single-point failures caused by lead screw jamming, which conventional dual-redundant electromechanical actuators cannot handle.

[0005] The technical solution adopted by this invention to solve its technical problem is: a fully electric dual-redundant emergency retraction electromechanical actuator, comprising: a gear transmission assembly encapsulated on one side of the EMA outer cylinder transmission box of the electromechanical actuator and connected to the output shaft of the main motor 1; a lead screw pair 3 connected to the gear transmission assembly; a piston cylinder assembly 8 that performs telescopic linear motion in the moving cavity of the EMA outer cylinder 4; and a lead screw nut 6 fitted on the outer helical raceway of the lead screw pair 3. The piston cylinder assembly 8 is characterized by having a symmetrically opposite main motor 1 at its free end, and a fully electric dual-redundant auxiliary motor 9 that serves as a backup to the main motor 1. The output gear of the auxiliary motor 9 meshes with a lead screw sleeve 7 cylinder end gear assembled in the piston cylinder assembly 8 via an auxiliary transmission gear 10. The cylinder end gear has a stepped... The piston cylinder assembly 8 is constrained by the bearing through the step on the inner wall of the piston cylinder assembly 8. The flange ring of the screw sleeve 7, which extends into the inner ring hole of the piston head step, is constrained on the end ring of the terminal bearing. The helical raceway inside the screw sleeve 7 is fitted with the screw nut 6, which moves in extension and retraction within its motion cavity. The screw nut 6 is fitted with the screw pair 3, which extends into the piston head. The screw pair 3 is fixed along the guide rail 5 at the bottom of the EMA outer cylinder 4, driving the piston cylinder assembly 8 to make a push-pull linear motion in the step-constrained motion cavity inside the EMA outer cylinder 4. This forms a situation where the main motor 1 drives the screw pair 3 to mesh with the screw nut 6 to rotate, or the auxiliary motor 9 drives the screw sleeve 7 to mesh with the screw nut 6 to rotate, pushing the piston cylinder assembly 8 to move in the motion cavity of the EMA outer cylinder (4). It has two relatively independent dual-redundant emergency retraction and extension transmission chains.

[0006] Compared with the prior art, the present invention has the following advantages: This invention employs a gear transmission assembly encapsulated on one side of the transmission box of the EMA outer cylinder and connected to the output shaft of the main motor 1; a lead screw pair 3 connected to the gear transmission assembly; a piston cylinder assembly 8 that performs telescopic linear motion within the moving cavity of the EMA outer cylinder 4; a lead screw sleeve 7 constrained by a bearing and mounted in the stepped hole of the piston head at the large end of the piston cylinder assembly 8; and a lead screw nut 6 fitted onto the outer helical raceway of the lead screw pair 3. The structure is simple, safe, and reliable. This invention features a symmetrical main motor 1 mounted on the free end of the piston cylinder assembly 8, and a fully electric dual-redundant auxiliary motor 9 serving as a backup. The output gear of the auxiliary motor 9 meshes with the end gear of the lead screw sleeve 7 via a secondary transmission gear 10. The lead screw sleeve 7 engages with the lead screw nut 6, which is mounted on a guide rail 5 fixed to the bottom end of the EMA outer cylinder 4. In redundant operating mode, the main motor sets a reference position and notifies the auxiliary motor via SPI, with both motors operating at the same reference position. If a fault is detected in the auxiliary motor, the main motor brakes, and the auxiliary motor no longer relies on the reference position given by the main motor but uses its own reference position command to continue operating the system. Experimental results show that because the auxiliary motor can quickly take over from the main motor to achieve position servoing, the system can achieve redundant control in fault conditions, possessing a certain degree of fault tolerance and improving system reliability.

[0007] This invention designs independent helical raceways on the inner and outer rings of the lead screw nut 6. The inner ring engages with the lead screw assembly 3, and the outer ring engages with the lead screw sleeve 7. This allows the lead screw assembly 3 to be driven by the main motor 1, and the lead screw sleeve 7 to be driven by the auxiliary motor 9. These form two relatively independent transmission chains integrated together by the piston cylinder 8. The two opposing channels create a dual-machine hot backup to fully utilize redundancy characteristics, ensuring high system reliability. Furthermore, it allows for automatic, non-disruptive switching of operating modes in case of failure. It exhibits high reliability. When the main motor 1 and auxiliary motor 9 can work simultaneously, the piston cylinder can be retracted under the condition of only power supply, achieving full electric redundancy in emergency response. The piston cylinder extension or retraction speed is twice the speed when a single motor is working. When any motor fails or its corresponding transmission chain is jammed, the other motor can independently complete the piston cylinder retraction task. In the case of failure of a motor or jamming of the transmission chain, the other motor and transmission components can complete the piston cylinder retraction action, which not only improves the safety and reliability of the all-electric actuator, but also solves the problem of single-point failure of the lead screw pair jamming that conventional electromechanical actuators cannot solve. Attached Figure Description

[0008] Figure 1 A schematic diagram of the piston cylinder extension state of the fully electric dual-redundant emergency retraction and deployment electromechanical actuator of the present invention.

[0009] In the diagram: 1. Main motor, 2. Main transmission gear, 3. Lead screw pair, 4. Outer cylinder, 5. Guide rail, 6. Lead screw nut, 7. Lead screw sleeve, 8. Piston cylinder, 9. Secondary motor, 10. Secondary transmission gear.

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this does not limit the invention to the scope of the described embodiments. All these concepts should be considered as the content disclosed in this technology and the scope of protection of this invention. Detailed Implementation

[0011] See Figure 1In the preferred embodiment described below, a fully electric dual-redundant emergency retraction electromechanical actuator includes: a gear transmission assembly encapsulated on one side of the EMA outer cylinder transmission box of the electromechanical actuator and connected to the output shaft of the main motor 1; a lead screw pair 3 connected to the gear transmission assembly; a piston cylinder assembly 8 that performs telescopic linear motion in the moving cavity of the EMA outer cylinder 4; and a lead screw nut 6 fitted on the outer helical raceway of the lead screw pair 3. The piston cylinder assembly 8 has a symmetrically opposite main motor 1 at its free end, and a fully electric dual-redundant auxiliary motor 9 that serves as a backup to the main motor 1. The output gear of the auxiliary motor 9 meshes with a lead screw sleeve 7 cylinder end gear assembled in the piston cylinder assembly 8 via an auxiliary transmission gear 10. This cylinder end gear stepped cylinder is connected to a live screw sleeve 7 cylinder end gear. The bearing constrained by the inner wall step of the piston cylinder assembly 8 constrains the flange ring of the screw sleeve 7, which extends into the inner ring hole of the piston head step, onto the end ring of the terminal bearing. The helical raceway inside the screw sleeve 7 is fitted with the screw nut 6, which moves in extension and retraction within its motion cavity. The screw nut 6 is fitted with the screw pair 3, which extends into the piston head, and is fixedly connected to the guide rail 5 at the bottom of the EMA outer cylinder 4. This drives the piston cylinder assembly 8 to make a linear push-pull motion within the step-constrained motion cavity of the EMA outer cylinder 4. This forms a system where the main motor 1 drives the screw pair 3 to mesh with the screw nut 6 to rotate, or the auxiliary motor 9 drives the screw sleeve 7 to mesh with the screw nut 6 to rotate, thus pushing the piston cylinder assembly 8 to move within the motion cavity of the EMA outer cylinder 4. This system has two relatively independent dual-redundant emergency retraction and deployment transmission chains.

[0012] The gear transmission assembly includes: a main transmission gear 2 on one side of the outer cylinder 4 transmission box that meshes with the output gear of the main motor 1, and a stepped shaft gear pair at the end of the lead screw pair 3 that meshes with the main transmission gear 2.

[0013] The gear transmission assembly further includes: an output gear of an auxiliary motor 9 corresponding to the main motor 1, encapsulated in the end transmission housing of the piston cylinder 8; an auxiliary transmission gear 10 meshing with the output gear; and a stepped shaft gear at the end of the piston cylinder 8 meshing with the auxiliary transmission gear 10.

[0014] The lead screw assembly 3 is axially limited by the thrust angular contact ball bearing mounted in the hollow stepped hole of the bottom cylinder of the EMA outer cylinder 4, which limits the gear pair of the stepped shaft of the lead screw assembly 3 to the two end faces of the lead screw ring groove. It moves along the guide rail 5 through the inner ring guide groove of the lead screw nut 6 and bears the load of the lead screw assembly 3.

[0015] The outer helical raceway of the lead screw assembly 3, in conjunction with the lead screw nut 6, constrains the lead screw nut 6 onto the helical raceway within the transmission cavity of the lead screw sleeve 7.

[0016] The lead screw sleeve 7, which meshes with the auxiliary transmission gear 10, is axially constrained by the axial stepped cylinder of the cylinder end gear on the upper end face of the piston cylinder 8 and the inner ring groove end face of the thrust angular contact ball bearing in the stepped hole of the end cylinder, thereby limiting the axial movement of the lead screw sleeve 7.

[0017] The lead screw sleeve 7 is constrained on one end face of the inner ring hole in the piston head of the piston cylinder 8 by the thrust angular contact ball bearing assembled by the end flange ring, and bears the load of the lead screw nut 6 that is matched with it.

[0018] The piston head at the free end of the piston cylinder 8 is fitted with the outer cylinder 4. The outer cylinder 4 constrains the piston head step ring through the inner wall step at the end, thus limiting the axial movement stroke freedom of the piston cylinder 8 in the moving cavity of the outer cylinder 4.

[0019] The lead screw sleeve 7, which is assembled in the transmission chamber of the piston cylinder 8, transmits the piston cylinder load sequentially to the lead screw nut 6, the lead screw pair 3, and finally to the outer cylinder 4.

[0020] During normal operation, the fully electric dual-redundant main motor 1 and auxiliary motor 9 can be selected to work simultaneously or either one of them can work while the other motor is in cold backup. When the main motor 1 and auxiliary motor 9 work simultaneously, the main motor 1 drives the lead screw pair 3 through the main transmission gear 2 to drive the lead screw nut 6 and lead screw sleeve 7 to retract. The auxiliary motor 9 drives the lead screw sleeve 7 to rotate through the auxiliary transmission gear 10, which in turn drives the piston cylinder 8, which is constrained by the thrust angular contact ball bearing at the end of the sleeve, to retract relative to the lead screw nut 6.

[0021] In the dual-redundant mode, if the main motor 1 is working and the auxiliary motor 9 fails or the transmission chain is jammed, the main motor 1 drives the lead screw pair 3 to rotate through the main transmission gear 2, which drives the lead screw nut 6 to drive the lead screw sleeve 7 and the fitted piston cylinder 8 to overcome the load of the piston cylinder 8 and make a retraction movement.

[0022] If the main motor 1 fails or the transmission chain is jammed, the auxiliary motor 9 will work. The auxiliary motor 9 will drive the lead screw sleeve 7 to rotate through the auxiliary transmission gear 10, and drive the piston cylinder 8 through the lead screw nut 6, so as to overcome the load of the piston cylinder 8 and make a retraction movement.

[0023] Although the present invention has been described in conjunction with some preferred embodiments, the invention is not limited to these embodiments. Rather, the invention is intended to encompass all alternatives, modifications, and equivalents, provided that such alternatives are included within the core spirit and scope of the invention as defined by the appended claims.

Claims

1. A fully electric dual-redundant emergency retraction electromechanical actuator, comprising: The main motor (1), a gear transmission assembly encapsulated on one side of the transmission box of the electromechanical actuator EMA outer cylinder (4) and connected to the output shaft of the main motor (1), a lead screw (3) connected to the gear transmission assembly, a piston cylinder assembly (8) that performs telescopic linear motion in the motion cavity of the EMA outer cylinder (4), and a lead screw nut (6) fitted on the outer helical raceway of the lead screw (3), characterized in that: the free end of the piston cylinder assembly (8) is provided with a fully electric dual-redundant auxiliary motor (9) that is symmetrical to the main motor (1) and serves as a backup for the auxiliary motor (9), and the gear transmission assembly includes: a main transmission gear (2) that meshes with the output gear of the main motor (1) on one side of the transmission box of the EMA outer cylinder (4), and a lead screw nut (6) that is fitted on the outer helical raceway of the lead screw (3). The gear transmission assembly further includes: an auxiliary motor (9) output gear corresponding to the output gear of the main motor (1) encapsulated in the terminal transmission housing of the piston cylinder assembly (8); an auxiliary transmission gear (10) meshing with the output gear of the auxiliary motor (9); and a screw sleeve (7) cylinder end gear meshing with the auxiliary transmission gear (10). The auxiliary motor (9) output gear meshes with the screw sleeve (7) cylinder end gear assembled in the piston cylinder assembly (8) through the auxiliary transmission gear (10). The stepped cylinder of the cylinder end gear is constrained by the bearing of the inner wall step of the piston cylinder assembly (8), which holds the flange of the screw sleeve (7) extending into the inner ring hole of the piston head step. The screw sleeve (7) is attached to the end ring of the terminal bearing. The inner helical raceway of the screw sleeve (7) is fitted onto the screw nut (6), wherein the screw nut (6) performs telescopic movement in the motion cavity of the screw sleeve (7). The screw nut (6) fits onto the screw (3) that extends into the piston head and moves along the guide rail (5) fixed at the bottom end of the EMA outer cylinder (4), driving the piston cylinder assembly (8) to perform a push-pull linear motion in the motion cavity constrained by the inner step of the EMA outer cylinder (4). This forms a situation where the main motor (1) drives the screw (3) to mesh with the screw nut (6) to rotate, or the auxiliary motor (9) drives the screw sleeve (7) to mesh with the screw nut (6) to rotate, pushing the piston cylinder assembly (8) to move in the motion cavity of the EMA outer cylinder (4). It has two relatively independent dual-redundant emergency retraction and extension transmission chains; the piston head of the piston cylinder assembly (8) is fitted with the EMA outer cylinder (4) at the free end. The EMA outer cylinder (4) constrains the piston head step ring through the inner wall step of the terminal, which restricts the stroke freedom of the piston cylinder assembly (8) in the motion cavity of the EMA outer cylinder (4); in the dual-redundant mode, if the auxiliary motor (9) fails or the transmission chain is jammed, the main motor (1) works. The main motor (1) drives the lead screw (3) to rotate through the output gear of the main motor (1), the main transmission gear (2) and the step shaft gear at the end of the lead screw (3), which drives the lead screw nut (6) to drive the lead screw sleeve (7) and the piston cylinder assembly (8) to overcome the load of the piston cylinder assembly (8) and make a retraction movement;If the main motor (1) fails or the transmission chain jams, the auxiliary motor (9) will operate. The auxiliary motor (9) will drive the lead screw sleeve (7) to rotate through the output gear of the auxiliary motor (9), the auxiliary transmission gear (10), and the end gear of the lead screw sleeve (7). This will drive the lead screw nut (6) to drive the piston cylinder assembly (8), overcoming the load of the piston cylinder assembly (8) to perform a retraction motion.

2. The all-electric dual-redundant emergency retraction electromechanical actuator as described in claim 1, characterized in that: The lead screw (3) is mounted on a thrust angular contact ball bearing through the hollow stepped hole in the bottom cylinder of the EMA outer cylinder (4). The step shaft gear at the end of the lead screw (3) is axially limited to the two end faces of the lead screw ring groove. It passes through the inner ring guide groove of the lead screw nut (6) and moves along the guide rail (5) to bear the load of the lead screw (3).

3. The all-electric dual-redundant emergency retraction electromechanical actuator as described in claim 1, characterized in that: The lead screw sleeve (7) meshes with the auxiliary transmission gear (10), and the lead screw sleeve (7) is axially limited by the axial stepped cylinder of the cylinder end gear, which is constrained by the upper end face of the piston cylinder assembly (8) and the inner ring groove end face of the thrust angular contact ball bearing in the stepped hole of the end cylinder.

4. The all-electric dual-redundant emergency retraction electromechanical actuator as described in claim 1, characterized in that: The lead screw sleeve (7) is constrained on one side end face of the inner ring hole in the piston head of the piston cylinder assembly (8) by the thrust angular contact ball bearing assembled by the end flange ring, and bears the load of the lead screw nut (6) that is matched with it.

5. The all-electric dual-redundant emergency retraction electromechanical actuator as described in claim 1, characterized in that: The lead screw sleeve (7) assembled in the transmission cavity of the piston cylinder assembly (8) transmits the load of the piston cylinder assembly (8) sequentially to the lead screw nut (6), the lead screw (3), and finally to the EMA outer cylinder (4).

6. The all-electric dual-redundant emergency retraction electromechanical actuator as described in claim 1, characterized in that: During normal operation, the main motor (1) and the auxiliary motor (9) can work simultaneously or either motor can work while the other motor is in cold standby. When the main motor (1) and the auxiliary motor (9) work simultaneously, the main motor (1) drives the lead screw (3) through the main transmission gear (2) to drive the lead screw nut (6) and the lead screw sleeve (7) to retract. The auxiliary motor (9) drives the lead screw sleeve (7) to rotate through the auxiliary transmission gear (10), which in turn drives the piston cylinder assembly (8) constrained by the thrust angular contact ball bearing in the end-mounted sleeve to retract relative to the lead screw nut (6).

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