CN219139745U

CN219139745U - High fault tolerance blocking electromechanical actuator

Info

Publication number: CN219139745U
Application number: CN202223467562.6U
Authority: CN
Inventors: 匡克焕; 刘崇武; 郭绍军
Original assignee: SICHUAN LINGFENG AVIATION HYDRAULIC MACHINERY CO Ltd
Current assignee: SICHUAN LINGFENG AVIATION HYDRAULIC MACHINERY CO Ltd
Priority date: 2022-12-25
Filing date: 2022-12-25
Publication date: 2023-06-06
Anticipated expiration: 2032-12-25

Abstract

The high-fault-tolerance blocking electromechanical actuator provided by the utility model has the fault tolerance capability of higher dual-redundancy safety and reliability. The method is realized by the following technical scheme: the spline transmission shaft with the round table plunger at the free end is matched with the auxiliary screw barrel in a circumferential guide key manner, is axially limited at the bottom end of the main screw nut through the bearing inner ring, and simultaneously points to the outlet end of the piston rod barrel along with the spline transmission shaft through the auxiliary screw barrel limited on the axial end surface of the bearing through the main screw nut; the upper steel ball assembled in the front and rear direction of the piston head of the piston rod barrel is restrained in the corresponding locking groove of the inner cavity wall of the cylinder barrel, the upper locking bush and the lower locking bush which are oppositely symmetrical are attached to the piston head to restrain the locking spring on the stop clamping rings at two ends of the annular groove of the main screw nut sleeve, and the mechanical locking mechanism for locking and unlocking the piston rod barrel is formed by rolling the upper steel ball and the lower steel ball between the upper locking bush and the outer annular chamfer inclined surface of the lower locking bush respectively in the telescopic movement of the piston rod barrel.

Description

High fault tolerance blocking electromechanical actuator

Technical Field

The utility model belongs to the technical field of electromechanical servo, and particularly relates to a dual-redundancy function emergency unlocking, extending and locking structure which can be widely applied to an all-motor electric actuator in a device follow-up system, an electric folding system, an electric winch system, a steering engine control system, an electric retraction system and an intelligent robot.

Background

With the maturation of multi-electric aircraft and all-electric aircraft technologies, what actuating systems are developed from hydraulic actuating systems to electric actuating systems. The actuator is a transmission mechanism for the motion control device to perform a maneuvering action. The electric actuator used as the linear motion actuator integrates the motor EMA, the reduction gearbox reducer, the cylinder barrel assembly, the ball screw transmission part, the piston rod barrel assembly, the self-locking assembly and the like and the controller, thereby overcoming the defects inherent to the traditional hydraulic system and ensuring that the novel integrated actuating system has small volume, light weight and high efficiency. Especially, the permanent magnet brushless direct current motor is used as a power source of the EMA, so that the digitization and integration of the servo actuating system are easy to realize, and the universality and maintainability of the actuating system are greatly improved. The actuator is a transmission machine which is used for the motion control device to perform the maneuvering action, and the output command signals of the servo controller/driver are converted into mechanical quantities such as speed, displacement, load and the like, so that the purposes of speed driving, displacement driving and load driving of a control object are realized. It is reported that the locking device has the function of a hydraulic retraction system under the same condition, and the locking device can achieve reliable locking by utilizing the dead point principle of a motion mechanism; however, the locking type structure is relatively complex and the movement space of the mechanism is large. In China, an electric retraction actuator of an undercarriage electric retraction system developed by an aviation enterprise can basically realize the basic function of electric retraction, but lacks a redundancy structure, and the locking device is complex in mechanism, multiple in structural parts and more in fault points, cannot meet the reliability requirement of an undercarriage of an airplane, and needs to be further improved. How to improve the reliability of the system; how to increase the power density of the system. In improving reliability, redundancy technology, i.e. implementation of redundancy design for the system, is mainly applied. The main method for improving the power density of the system is to apply a high-power density motor to realize transmission. The dual-redundancy electric actuator adopts redundancy technology, is safe and reliable, has high output power and light weight, and is an electromechanical integrated full-electric servo actuator with optimal comprehensive performance. The all-electric actuator is a new thing, has late appearance and rapid development, is still in a research stage in China, and has not been practically applied in an aviation aircraft control system. The recently developed full-electric transmission hydraulic servo system occupies a relatively large weight of the system, and the electromechanical actuator used as a servo clothes actuator of a flight control system is not beneficial to system integration, reduces reliability and cannot eliminate torque fighting among redundant motors. To eliminate the electromagnetic torque fighting among the redundancy motors, the problem of inconsistent feedback channels among the redundancy motors must be solved.

At present, an electromechanical actuator serving as a transmission mechanism has a function of being driven to rotate according to an instruction after being electrified. The process from the motor of the electromechanical actuator to the rudder shaft of the aircraft is a speed-reducing and moment-increasing process. Accordingly, it is desirable to mount a corresponding locking device on the motor shaft of the electromechanical actuator when it is not energized to provide the desired locking torque after deceleration and torque multiplication. Electromechanical actuators (EMA) are critical components of flight control systems whose reliability directly affect the flight safety of an aircraft. Because the landing gear of modern aircraft is usually retractable, normally utilize hydraulic pressure to carry out landing gear normal retraction and locking, when the landing gear can't normally put down because of the trouble of aircraft hydraulic pressure, electrical system etc. system, the aircraft must have the measure of manual emergency landing gear and locking, and its working property directly influences the security of aircraft. However, in the past, a plurality of aircraft landing gear emergency release systems are extremely important for ensuring flight safety because the landing gear cannot be effectively locked after emergency release or the situation that the aircraft is forced to descend is caused.

In certain applications with high safety requirements, such as electromechanical actuators for retraction of aircraft landing gear, it is required that they must have a certain safety margin. The conventional redundancy scheme adopts a main and standby driving mode of a motor and a pneumatic motor, belongs to dissimilar redundancy design, and improves the reliability of a system. How to realize the full-electric retraction of the landing gear is always a technical problem in the development process of the full-electric aircraft. The conventional single-redundancy electromechanical actuating structure cannot meet the design requirements. In some redundant linear transmission actuating mechanisms, force disputes are easy to generate, and the use is limited. Under the condition of high-load and high-stroke electromechanical actuation requirement, the cantilever type lead screw bearing support structure has small support rigidity, and the lead screw is easy to deform in a buckling way. In mechanical transmission, the ball screw pair has potential safety hazards of clamping due to overload, fatigue and the like. And the redundancy of the common electromechanical actuator is designed as a motor for backing up one, when the main motor fails, the standby motor works to realize emergency lowering or withdrawing of the piston rod cylinder, but the single-point failure of the screw rod pair blocking plug cannot be solved, the task reliability is low, and the practicability is poor.

Disclosure of Invention

Aiming at the high reliability requirement of the EMA of the landing gear emergency release system, the utility model adopts redundancy technology, provides a high fault tolerance blocking electromechanical actuator scheme which can relieve blocking, clamping stagnation and blocking faults, has higher dual redundancy safety and reliability fault tolerance capability, and can realize high fault tolerance of emergency extension and reliable locking of a piston rod barrel under the supply of electric power only. The problem that a conventional dual-redundancy electromechanical actuator cannot solve single-point faults of a screw pair blocking is solved, and full-electricity redundancy unlocking, extending and locking are achieved.

The technical scheme adopted for solving the technical problems is as follows: a high fault tolerance blocking electromechanical actuator comprising: the two sides of the symmetrical cylinder barrel 3 adopt a double-redundancy main motor 1 and an auxiliary motor 20 which are in a rotary output form as power sources, are used as electromechanical energy conversion units for driving a main screw gear and a transmission shaft gear by a main motor shaft connecting gear and an auxiliary motor shaft connecting gear, and are used for changing rotary motion into linear motion through a main screw barrel 4 of a cylinder barrel 3 cylinder body and a main screw nut 6 sleeved on an outer spiral rollaway of the main screw barrel 4 to drive a piston rod barrel 10 to do stretching motion in a transmission cavity of the cylinder barrel 3, and are characterized in that: the spline transmission shaft 22 with the round table plunger at the free end is matched with the auxiliary screw barrel 8 in a circumferential guide key manner, the inner ring of the bidirectional thrust angular contact ball bearing 7 is axially limited at the bottom end of the main screw nut 6, and meanwhile, the auxiliary screw barrel 8 limited on the axial end surface of the bidirectional thrust angular contact ball bearing 7 is axially limited in a hollow stepped hole of the main screw nut 6 and points to the outlet end of the piston rod barrel 10 along with the spline transmission shaft 22; the upper steel ball 17 assembled in the upper steel ball guide hole 16 in the front and back directions of the bus of the outer ring surface of the piston head of the piston rod barrel 10 is restrained in the corresponding locking groove of the inner cavity wall of the cylinder barrel 3, the lower steel ball 13 falling and locked in the lower steel ball guide hole 12 is attached to the inner ring surface of the cylinder barrel 3, the upper locking bush 19 and the lower locking bush 14 which are symmetrical in opposite directions restrain the locking spring 15 on the stop clamping rings at two ends of the ring groove of the auxiliary screw nut sleeve, and a mechanical locking mechanism for rolling and locking and unlocking the upper steel ball 17 and the lower steel ball 13 between the upper locking bush 19 and the outer ring surface chamfer of the lower locking bush 14 is formed in the telescopic movement of the piston rod barrel 10.

Compared with the prior art, the utility model has the following gain effects:

the utility model adopts a main-standby dissimilar redundancy design consisting of the two sets of identical servo motors and the double redundancy main motor 1 and the auxiliary motor 20 which control the driving device to serve as power sources, and the redundancy motors are in the same phase to ensure that the motors are easy and convenient to change phase, so that the reliability of a retraction system can be ensured, and the reliability requirement of a landing gear is met. The dual-redundancy electromechanical energy conversion unit which is used as a main motor shaft and auxiliary motor shaft connecting gear to drive a main screw gear and a transmission shaft gear for transmission has outstanding reliability and good fault tolerance. Simple and convenient, and strong real-time performance. The main screw rod cylinder 4 which changes rotary motion into linear motion and the main screw rod nut 6 which is sleeved on the outer spiral rollaway nest of the main screw rod cylinder 4 are arranged in the cylinder body of the cylinder barrel 3, the piston rod cylinder 10 is driven to stretch out of the transmission cavity of the cylinder barrel 3, the auxiliary screw rod cylinder 8 which can bear load and can be driven to rotate freely can be formed by axially assembling the main screw rod nut 6 in each channel output isolation control, the main screw rod cylinder 4 can be driven by the main motor 1, the auxiliary screw rod cylinder 8 can be driven by the auxiliary motor 20, and two relatively independent actuator control channel transmission chains are formed and are integrated together by the piston rod cylinder 10. High transmission precision, high transmission efficiency and high bearing capacity. The main motor 1 and the auxiliary motor 20 can work simultaneously, also can work singly, and the other motor is backed up, can realize the unlocking, the movement and the locking actions of the piston rod barrel, and when any motor fails or the corresponding transmission chain is blocked, the other motor can independently finish the tasks of unlocking, extending and locking the upper lock and the lower lock of the extending piston rod barrel, thereby solving the problem that the conventional electromechanical actuator with the locking function cannot solve the problem of single-point fault of the blocking of the screw rod auxiliary. Experimental results show that, as the spline transmission shaft 22 is matched with the auxiliary screw barrel 8 in a circumferential guide key manner, the inner ring of the bidirectional thrust angular contact ball bearing 7 is axially limited at the bottom end of the main screw nut 6, the integration level is high, and the reliability is high: the position servo can be realized in a relatively rapid succession, the redundancy control can be realized under the fault condition, the jamming fault of the mechanical transmission mechanism is eliminated, and the reliability of the EMA is improved. And meanwhile, the strong output force capacity of the actuator is inherited. When any redundancy position feedback channel fails, the position feedback channels with the other redundancy can be shared to work simultaneously in parallel, so that the reliability of the system is improved.

The utility model is limited at the bottom end of the main screw nut 6 through the inner ring of the bidirectional thrust angular contact ball bearing 7, and simultaneously, the auxiliary screw cylinder 8 limited on the axial end surface of the bidirectional thrust angular contact ball bearing 7 is pointed at the outlet end of the piston rod cylinder 10 along with the spline transmission shaft 22 through the hollow step hole of the main screw nut 6; the positioning precision is high, so that the bearing capacity and the rigidity are greatly improved: and the supporting rigidity and the supporting stability of the step-by-step loading of the actuating mechanism under the requirement of large stroke are improved. Compared with the structural layout and the functional form of the traditional electromechanical actuator, the bearing capacity is relatively larger, the transmission precision is higher, the safety and the reliability are higher, and the jamming, clamping stagnation and jamming faults can be relieved.

The utility model adopts an upper steel ball 17 assembled in an upper steel ball guide hole 16 in the front-back direction of a bus of the outer ring surface of a piston head of a piston rod barrel 10, the upper steel ball 17 restrained in a corresponding locking groove of the inner cavity wall of a cylinder barrel 3 is attached to the inner ring surface of the piston head, a locking spring 15 is restrained on stop clamping rings at two ends of a ring groove of a sleeve of an auxiliary screw nut 9 by an upper locking bushing 19 and a lower locking bushing 14 which are symmetrical in opposite directions, and a mechanical locking mechanism for rolling and locking and unlocking the upper steel ball 17 and the lower steel ball 13 between the upper locking bushing 19 and the outer ring chamfer of the lower locking bushing 14 respectively in the telescopic movement of the piston rod barrel 10 is formed. The steel balls then withdraw from the locking grooves of the cylinder barrel 3 under the action of the axial movement of the piston, so that unlocking is realized; when the locking mechanism is in the locking position, the steel balls enter the cylinder barrel locking groove under the movement, and at the moment, the upper locking bushing 19 and the lower locking bushing 14 keep the steel balls in the piston barrel locking groove under the action of spring force, so that locking is realized. The ends of the annular snap rings of the upper locking bushing 19 and the lower locking bushing 14, which are in contact with the steel balls, are provided with certain chamfers, so that the steel balls can exit and enter easily. The adopted annular steel ball structure can realize the separation of force transmission and transmission, ensure the transmission precision and the service life of the transmission screw rod and simultaneously have reliable bearing capacity; the main screw rod with redundancy function is adopted as a main working transmission pair, the auxiliary screw rod is used as a non-similar redundancy design of the backup separation and locking actuator, the rotation of the main and backup working screw rods can be controlled, multi-type redundancy designs such as control, driving and feedback are realized, and the backup screw rod can work in full stroke when the main working screw rod is blocked at any position. The screw pair can be ensured to work continuously under the condition of one-time fault.

The spline transmission shaft 22 of the utility model is provided with a plunger round table arranged at one axial end far away from the inner screw nut; the driving screw rod cylinders 4 which extend into the axial direction are assembled together through the round table, power is transmitted to the spline transmission shaft 22 from the transmission gear, the spline transmission shaft 22 is transmitted to the auxiliary screw rod cylinders 8 through key and groove matching transmission, and the driving rod is driven to output linear motion by means of reaction force. When the auxiliary screw rod barrel 8 is blocked, the main screw rod nut 6 drives the auxiliary screw rod barrel 8 and the auxiliary screw rod nut 9 which are blocked mutually to release the upper steel ball lock, the auxiliary screw rod barrel 8 and the auxiliary screw rod nut 9 are pushed to slide along the piston head, and the piston rod barrel 10 outputs linear motion. Under the working condition that one motor of the actuator fails or a transmission chain is blocked, the other motor and a transmission part can complete the actions of unlocking, extending and locking the piston rod cylinder. Can prevent the movement of the vehicle caused by external force when the vehicle stops moving at a limited position. In the locked state, the external impact load is transmitted to the piston cylinder of the main bearing part through the locking mechanism, and the screw rod is not basically acted by the impact load. The transmission and bearing separation is realized, and the transmission sugar degree and the service life of the lead screw are ensured.

The utility model can improve the safety and the task reliability of the all-motor electric actuator with the locking function. The method can not only finish rated thrust output, speed output and position output, but also realize fault relief of screw rod jamming, clamping stagnation and jamming problems by utilizing an external independent control method and an unlocking mechanism, thereby being beneficial to popularization and application in more fields,

Drawings

FIG. 1 is a schematic diagram of the structure of the high fault tolerance blocking electromechanical actuator piston rod cartridge in the retracted state of the present utility model.

Fig. 2 is a left side view in partial cross section of the drive shaft and lead screw spline engagement of fig. 1.

Fig. 3 is a schematic view of the piston cylinder of fig. 1 in an extended state.

In the figure: the novel high-speed hydraulic transmission device comprises a main motor 1, a main transmission gear 2, a cylinder barrel 3, a main screw barrel 4, a thrust angular contact ball bearing 5, a main screw nut 6, a bidirectional thrust angular contact ball bearing 7, an auxiliary screw 8, an auxiliary screw nut 9, a piston rod barrel 10, a lower steel ball locking groove 11, a lower steel ball guiding hole 12, a lower steel ball 13, a lower locking bushing 14, a locking spring 15, an upper steel ball guiding hole 16, an upper steel ball 17, an upper steel ball locking groove 18, an upper locking bushing 19, an auxiliary motor 20, an auxiliary transmission gear 21 and a spline transmission shaft 22.

The utility model will be further described with reference to the drawings and examples, without thereby restricting the utility model to the scope of the examples. All such concepts should be considered as being generic to the disclosure herein and to the scope of the utility model.

Detailed Description

See fig. 1. In a preferred embodiment described below, a high fault tolerance blocking electromechanical actuator comprises: the two sides of the symmetrical cylinder barrel 3 adopt a double-redundancy main motor 1 and an auxiliary motor 20 which take a rotary output form as power sources, are taken as electromechanical energy conversion units for driving a main screw gear and a transmission shaft gear by a main motor shaft connecting gear and an auxiliary motor shaft connecting gear, and change rotary motion into linear motion through a main screw barrel 4 of a cylinder barrel 3 and a main screw nut 6 sleeved on an outer spiral raceway of the main screw barrel 4 to drive a piston rod barrel 10 to do stretching motion in a transmission cavity of the cylinder barrel 3, wherein: the spline transmission shaft 22 with the round table plunger at the free end is matched with the auxiliary screw barrel 8 in a circumferential guide key manner, the inner ring of the bidirectional thrust angular contact ball bearing 7 is axially limited at the bottom end of the main screw nut 6, and meanwhile, the auxiliary screw barrel 8 limited on the axial end surface of the bidirectional thrust angular contact ball bearing 7 is axially limited in a hollow stepped hole of the main screw nut 6 and points to the outlet end of the piston rod barrel 10 along with the spline transmission shaft 22; the upper steel ball 17 assembled in the upper steel ball guide hole 16 in the front and back directions of the bus of the outer ring surface of the piston head of the piston rod barrel 10 is restrained in the corresponding locking groove of the inner cavity wall of the cylinder barrel 3, the lower steel ball 13 falling and locked in the lower steel ball guide hole 12 is attached to the inner ring surface of the cylinder barrel 3, the upper locking bush 19 and the lower locking bush 14 which are symmetrical in opposite directions restrain the locking spring 15 on the stop clamping rings at two ends of the ring groove of the sleeve of the auxiliary screw nut 9, and a mechanical locking mechanism for rolling and locking and unlocking the upper steel ball 17 and the lower steel ball 13 between the upper locking bush 19 and the lower locking bush 14 respectively in the telescopic movement of the piston rod barrel 10 is formed.

The electromechanical energy conversion unit includes: the output shaft of the main motor 1 extends into the transmission cavity of the movable cylinder 3 to be meshed with the main transmission gear 2 to drive the end direction gear transmission system of the main screw cylinder 4 to rotate, and the output shaft gear of the auxiliary motor 20 is meshed with the end direction gear transmission system of the spline transmission shaft 22 through the auxiliary transmission gear 21. The drive train has a plurality of gears coupled to each other for transmission to a plurality of interconnected gear outputs.

The main screw rod cylinder 4 which is driven by the spline transmission shaft 22 to rotate together is sleeved with the auxiliary screw rod cylinder 8 through the main screw rod nut 6, and the auxiliary screw rod cylinder 8 extends out of the stepped hole of the piston head to the cavity of the piston rod cylinder 10 through the auxiliary screw rod nut 9, so that the piston rod cylinder 10 is driven to do telescopic motion in the cylinder barrel 3.

The main screw rod cylinder 4 is axially limited on the end face of the through cylinder 3 through the inner ring of the thrust angular contact ball bearing 5, and the bidirectional thrust angular contact ball bearing 7 assembled in the hollow stepped hole of the main screw rod nut 6 limits the auxiliary screw rod cylinder 8 on the end face of the main screw rod nut 6 through the inner ring to bear the load of the auxiliary screw rod cylinder 8.

Under the retraction working condition, the piston head of the piston rod barrel 10 is hollow and faces the bottom end of the cavity of the cylinder barrel 3, and the auxiliary screw nut 9 assembled in the hollow stepped hole of the piston head of the piston rod barrel 10 sequentially transmits the load of the piston rod barrel to the auxiliary screw barrel 8, the main screw nut 6, the main screw barrel 4 and the thrust angular contact ball bearing 5, and finally to the cylinder barrel 3.

During normal operation, the main motor 1 and the auxiliary motor 20 can work simultaneously or any motor works, the other motor is used for cold backup, the main motor 1 and the auxiliary motor 20 work simultaneously, the main motor 1 drives the main screw rod barrel 4 to rotate through the main transmission gear 2, and the main screw rod nut 6 is driven to drive the auxiliary screw rod barrel 8 to extend.

The auxiliary motor 20 drives the auxiliary screw cylinder 8 to rotate through the shaft coupling gear meshing auxiliary transmission gear 20 and the spline transmission shaft 22, drives the auxiliary screw cylinder 8, the auxiliary screw nut 9 and the piston head to move rightwards, and is separated from the main screw nut 6, so that the upper locking bush 19 is pushed to move against the elastic force of the locking spring 15, the upper steel ball 17 rolls along the upper steel ball guide hole 16, is separated from the upper steel ball locking groove 18, the mechanical locking and unlocking of the upper steel ball 17 is realized, the auxiliary screw nut 9 pushes the piston rod cylinder 10 to extend out along the limiting position of the cavity of the cylinder barrel 3 after unlocking, the locking spring 15 pushes the lower steel ball 13 positioned in the lower steel ball guide hole 12 through the lower locking bush 14, rolls to the lower steel ball locking groove 11 along the inner wall of the cylinder barrel 3, the lower steel ball 13 is clamped into the outer annular surface through the lower locking bush 14, and the mechanical locking and locking of the lower steel ball 13 are realized, and the retraction process is similar.

If the main motor 1 works and the auxiliary motor 20 fails or the transmission chain is blocked, the main motor 1 drives the main screw rod barrel 4 to rotate through the main transmission gear 2, the main screw rod nut 6 is driven to drive the sleeved auxiliary screw rod barrel 8, the auxiliary screw rod nut 9 and the piston head are pushed to move rightwards, the mechanical locking and unlocking of the upper steel ball 17 is realized, the mechanical locking and locking of the lower steel ball 13 are realized, and the unlocking and locking processes are the same as the normal working processes.

If the main motor 1 fails or the transmission chain is blocked, the auxiliary motor 20 works, the auxiliary motor 20 drives the spline transmission shaft 22 to rotate through the auxiliary transmission gear 21, drives the auxiliary screw barrel 8 in spline engagement with the spline transmission shaft, drives the auxiliary screw barrel 8 to synchronously rotate, and drives the auxiliary screw nut 9 and the piston head to move rightwards, so that the mechanical locking and unlocking of the upper steel ball 17 and the mechanical locking and locking of the lower steel ball 13 are realized, and the unlocking and locking processes are the same as the normal working processes.

While the utility model has been described in connection with certain preferred embodiments, the utility model is not limited to those embodiments. On the contrary, the utility model is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the utility model as defined by the appended claims.

Claims

1. A high fault tolerance blocking electromechanical actuator comprising: the two sides of the symmetrical cylinder barrel (3) adopt a rotary output form as a dual-redundancy main motor (1) and an auxiliary motor (20) of a power source, are used as electromechanical energy conversion units for driving a main screw gear and a transmission shaft gear by a main motor shaft connecting gear, and are used for changing rotary motion into linear motion by a main screw barrel (4) and a main screw nut (6) sleeved on an outer spiral rollaway of the main screw barrel (4) through a thrust angular contact ball bearing (5) arranged in a cylinder body of the cylinder barrel (3), so as to drive a piston rod barrel (10) to stretch out in a transmission cavity of the cylinder barrel (3), and the symmetrical cylinder barrel is characterized in that: the spline transmission shaft (22) with the round table plunger at the free end is matched with the auxiliary screw barrel (8) in a circumferential guide key manner, the inner ring of the bidirectional thrust angular contact ball bearing (7) is axially limited at the bottom end of the main screw nut (6), and meanwhile, the auxiliary screw barrel (8) limited on the axial end surface of the bidirectional thrust angular contact ball bearing (7) is axially limited in a hollow step hole of the main screw nut (6) and points to the outlet end of the piston rod barrel (10) along with the spline transmission shaft (22); the upper steel ball (17) assembled in an upper steel ball guide hole (16) in the front-back direction of a bus of the outer ring surface of a piston head of the piston rod cylinder (10) is restrained in a corresponding locking groove of the inner cavity wall of the cylinder barrel (3), a lower steel ball (13) falling and locked on the lower steel ball guide hole (12) is attached to the inner ring surface of the cylinder barrel (3), upper locking bushings (19) and lower locking bushings (14) which are symmetrical in opposite directions restrain locking springs (15) on stop clamping rings at two ends of annular grooves of a sleeve of the auxiliary screw nut (9), and a mechanical locking mechanism for rolling and locking and unlocking the upper steel ball (17) and the lower steel ball (13) between the upper locking bushings (19) and the outer ring chamfer inclined surfaces of the lower locking bushings (14) respectively is formed in the telescopic movement of the piston rod cylinder (10).

2. The high fault tolerance blocking electromechanical actuator of claim 1, wherein: the electromechanical energy conversion unit includes: the output shaft of the main motor (1) stretches into a transmission cavity of the movable cylinder barrel (3) to be meshed with a main transmission gear (2) to drive an end direction gear transmission system with a main screw barrel (4) to rotate, and the output shaft gear of the auxiliary motor (20) is meshed with an end direction gear transmission system of a spline transmission shaft (22) through an auxiliary transmission gear (21).

3. The high fault tolerance blocking electromechanical actuator of claim 2, wherein: the drive train has a plurality of gears coupled to each other for transmission to a plurality of interconnected gear outputs.

4. The high fault tolerance blocking electromechanical actuator of claim 1, wherein: the auxiliary screw rod cylinder (8) which is driven by the spline transmission shaft (22) to rotate together is sleeved with the auxiliary screw rod cylinder (8) through the main screw rod nut (6), and the auxiliary screw rod cylinder (8) extends out of the step hole of the piston head to the cavity of the piston rod cylinder (10) through the auxiliary screw rod nut (9) to drive the piston rod cylinder (10) to do telescopic motion in the cylinder barrel (3).

5. The high fault tolerance blocking electromechanical actuator according to claim 4, wherein: the main screw rod cylinder (4) is axially limited on the end face of the cylinder passing cylinder (3) through an inner ring of the thrust angular contact ball bearing (5), and the bidirectional thrust angular contact ball bearing (7) assembled in the hollow step hole of the main screw rod nut (6) limits the auxiliary screw rod cylinder (8) on the end face of the main screw rod nut (6) through the inner ring to bear the load of the auxiliary screw rod cylinder (8).

6. The high fault tolerance blocking electromechanical actuator of claim 1, wherein: under the retraction working condition, a piston head of a piston rod cylinder (10) is hollow and faces to the bottom end of a cavity of a cylinder barrel (3), and an auxiliary screw nut (9) assembled in a hollow stepped hole of the piston head of the piston rod cylinder (10) sequentially transmits the load of the piston rod cylinder to the auxiliary screw cylinder (8), the main screw nut (6), the main screw cylinder (4) and the thrust angular contact ball bearing (5), and finally transmits the load to the cylinder barrel (3).

7. The high fault tolerance blocking electromechanical actuator of claim 1, wherein: the auxiliary motor (20) drives the auxiliary screw cylinder (8) to rotate through the shaft coupling gear meshing auxiliary transmission gear (21) and the spline transmission shaft (22), the auxiliary screw cylinder (8), the auxiliary screw nut (9) and the piston head are driven to move rightwards and separate from the main screw nut (6), the upper steel ball (17) is pushed to move against the elastic force of the locking spring (15), the upper steel ball (17) rolls along the upper steel ball guide hole (16) and is separated from the upper steel ball locking groove (18), the upper steel ball (17) is mechanically locked and unlocked, the auxiliary screw nut (9) pushes the piston rod cylinder (10) to extend out along the limit position of the cavity of the cylinder barrel (3) after unlocking, the locking spring (15) pushes the lower steel ball (13) positioned in the lower steel ball guide hole (12) to roll to the lower steel ball locking groove (11) along the inner wall of the cylinder barrel (3), the lower steel ball (13) is blocked into the outer annular surface through the lower steel ball locking sleeve (14), and the lower steel ball (13) is mechanically locked and retracted, and the process is similar.

8. The high fault tolerance blocking electromechanical actuator of claim 1, wherein: if the main motor (1) works, the auxiliary motor (20) fails or a transmission chain is blocked, the main motor (1) drives the main screw rod cylinder (4) to rotate through the main transmission gear (2), the main screw rod nut (6) is driven to drive the sleeved auxiliary screw rod cylinder (8), the auxiliary screw rod nut (9) and the piston head are pushed to move rightwards, the mechanical locking and unlocking of the upper steel ball (17) is realized, the mechanical locking and locking of the lower steel ball (13) are realized, and the unlocking and locking processes are the same as the normal working processes.

9. The high fault tolerance blocking electromechanical actuator of claim 8, wherein: if the main motor (1) fails or the transmission chain is blocked, the auxiliary motor (20) works, the auxiliary motor (20) drives the spline transmission shaft (22) to rotate through the auxiliary transmission gear (21), the auxiliary screw barrel (8) meshed with the spline transmission shaft is driven, the auxiliary screw barrel (8) is driven to synchronously rotate, the auxiliary screw nut (9) and the piston head are driven to move rightwards, and the mechanical locking and unlocking of the upper steel ball (17) and the mechanical locking and locking of the lower steel ball (13) are realized, wherein the unlocking and locking processes are the same as the normal working processes.