Internally locked emergency retract and unlock electromechanical actuator

Abstract

The present invention discloses an internally locked emergency retraction and unlocking electromechanical actuator, which effectively solves the problem that conventional dual-redundant electromechanical actuators still rely on electricity for emergency retraction and extension. The present invention is achieved through the following technical solutions: the radial necking groove of the screw nut corresponds to the locking guide groove of the nut sleeve, which is constrained by a slider provided below the nut sleeve. The slider is coupled to the emergency sleeve, axially constraining the locking force spring and the return spring that maintains the locking force to the end face of the piston head, the end face of the emergency sleeve, and the end face of the stepped cylinder locking sleeve. The screw nut drives the nut sleeve, pushing the stepped cylinder locking sleeve to overcome the elastic force of the return spring and the locking force spring, completing the rigid lock ball mechanical switching to lock or unlock. The actuator cylinder is linearly retracted into place to lock and unlock. The emergency energy inlet on the actuator communicates with the high-pressure medium emergency release circuit, compressing the return spring pre-loaded in the piston head, causing the stepped cylinder locking sleeve and the emergency sleeve to emergency release against the spring force, and the high-pressure medium to retract the piston cylinder.

Description

Technical Field

[0001] The present invention relates to the field of mechanics and, more specifically, to an emergency unlocking and retraction structure for an electromechanical actuator. More specifically, the present invention relates to an innovative structure that can improve the safety and mission reliability of the electromechanical actuator and achieve multi-media emergency unlocking and retraction of the piston cylinder when the actuator loses power or the transmission component is stuck. Background Art

[0002] With the advancement of modern technology, requirements for retractable or opening / closing mechanisms are increasing, including simple control systems, easy operation, compact structure, comprehensive functionality, reliable quality, stable performance, long life, lightweight, easy maintenance, low manufacturing and operating costs, and the ability to safely and quickly lower or open the mechanism in emergency situations. Since modern aircraft landing gear is typically retractable, typically hydraulically operated, manual emergency gear lowering is essential in the event of a failure in the hydraulic or electrical systems, leading to the inability to lower the landing gear properly. The operational performance of manual gear lowering directly impacts aircraft safety. However, there have been numerous instances of aircraft landing gear being improperly lowered, resulting in forced landings. This demonstrates the critical importance of emergency landing gear systems for ensuring flight safety. The actuator cylinder, which utilizes electrical energy for landing gear retraction and lowering, is a transmission mechanism that converts the rotation of the input shaft into linear motion of the actuator rod. If the screw and nut inside the actuator cylinder become stuck during load swinging, the actuator rod will no longer be able to extend or retract, and thus no longer be able to push the load, potentially leading to catastrophic failure. In this situation, an electrical control system and an internally locked electric actuator mechanism are needed to enable the actuator rod to continue pushing the load, minimizing the failure to a tolerable level. However, traditional internally locked electric actuators and their electrical control systems, particularly their emergency unlocking methods and forms, are gradually failing to adapt to the development of modern technology, especially modern aircraft technology.

[0003] An electromechanical actuator, as a linear motion actuator, is an energy conversion device used to achieve linear reciprocating motion or less than 360° in a working mechanism. The basic components of a common electromechanical actuator are as follows: a motor, a reduction gearbox, transmission components, a ball screw, a cylinder assembly, a piston assembly, and a self-locking assembly. The ball screw is the core transmission element of an electromechanical actuator, and its transmission reliability has a significant impact on the overall reliability of the actuator. To mitigate the impact of collisions between the ball screw and the ball nut at extreme transmission positions, traditional ball screws incorporate cushioning pads between the two elements. This solution, previously used in electromechanical servo mechanisms, utilizes cushioning pads as a passive anti-collision mechanism. However, in the event of a system power failure or closed-loop position control failure, the rigid collision and compression between the internal end faces of the ball screw at the extreme transmission positions of the electromechanical actuator can cause deformation of the ball screw raceway and increase clearance, reducing transmission accuracy and even causing the screw to jam and lose functionality. Electromechanical actuators with self-locking mechanisms prevent movement due to external forces when stopped at a defined position. These mechanisms are typically locked by a mechanical lock within the actuator cylinder. A common mechanical lock is a steel ball lock, consisting of a steel ball, a locking groove, a tapered piston, and a spring. Currently, electromechanical actuators, as transmission mechanisms, function to rotate according to commands when energized. The process from the electromechanical actuator's motor to the aircraft's rudder shaft involves a deceleration and torque accumulation process. Therefore, a locking device must be installed on the motor shaft when the actuator is not energized to provide the required locking torque after deceleration and torque accumulation. Certain safety-critical applications, such as those for aircraft landing gear retraction and extension, require a certain safety margin. Redundancy solutions employing electric and pneumatic motors as primary and backup drives are non-similar redundancy designs that improve system reliability. Internal locking solutions employ steel ball locks, enabling locking of the actuator cylinder in place, unlocking retraction and extension, and reliable locking. However, products capable of rapid unlocking in emergencies are rare. Common electromechanical actuator redundancy designs utilize a backup motor. If the primary motor fails, the backup motor operates to provide emergency piston extension or retraction. Conventional dual-redundant electromechanical actuators still rely on electricity for emergency extension and retraction. However, like primary and backup drive systems with electric and pneumatic motors, these actuators cannot address the single point of failure of the lead screw assembly jamming, resulting in low reliability and limited practicality. Summary of the Invention

[0004] The present invention aims to address the problems of the prior art by providing a simple, safe, and reliable solution that can achieve emergency unlocking and retraction of the piston cylinder independently of electricity. This solution effectively addresses the problem of conventional dual-redundant electromechanical actuators still relying on electricity for emergency retraction and extension, but cannot resolve the single point of failure of the lead screw assembly becoming stuck. The invention provides a redundant, emergency internally locked electromechanical actuator with emergency retraction and unlocking for different working media.

[0005] ] The technical solution adopted by the present invention to solve its technical problems is: an internally locked emergency retraction and unlocking electromechanical actuator, comprising: an electromechanical actuator cylinder 1 connected to the servo motor shaft gear through a gear transmission mechanism, a screw transmission pair 8 assembled in the transmission cavity of the cylinder 1 and engaged with the gear transmission mechanism, and a piston cylinder 6 and an anti-jamming follower mechanism for the cylinder 1 to perform telescopic movement, characterized in that: the piston head is hollow and faces the free end of the cylinder 1 cavity, the screw is converted into mechanical energy of the nut sleeve 9 mounted on the outer ring surface through the screw nut 7 assembled in the hollow stepped hole of the piston head, the radial necking groove 15 on the front of the screw nut 7 corresponds to the locking guide groove 16 of the nut sleeve 9, and is constrained by the slider 14 provided below the nut sleeve 9, and the slider 14 is coupled and connected The emergency sleeve 13 axially constrains the upper locking force spring 12 and the return spring 10 that maintains the upper locking force to the end face of the hollow step hole in the piston head and the end face of the emergency sleeve 13 and the end face of the locking sleeve 11 of the stepped cylinder. The screw nut 7 drives the nut sleeve 9 to push the locking sleeve 11 of the stepped cylinder to overcome the elastic movement of the return spring 10 and the upper locking force spring 12, completing the mechanical switching of the rigid locking ball 4 to lock or unlock. The piston cylinder 6 is linearly retracted into the locking and unlocking positions, and the emergency energy inlet 2 on the communicating actuator is used for the emergency release circuit of the high-pressure medium. The return spring 10 pre-loaded inside the piston head is compressed, and the locking sleeve 11 and the emergency sleeve 13 of the stepped cylinder overcome the spring force to emergency disengage from the rigid locking ball 4, and the lock is emergency unlocked. The high-pressure medium pushes the piston cylinder 6 to retract.

[0006] Furthermore, the anti-jamming follower mechanism is sleeved on the inner ring surface of the nut sleeve 9 through the outer ring surface of the screw nut 7, and a locking guide groove 16 is provided at the end of the nut sleeve 9 relative to the radial necking groove 15 at the front of the screw nut 7, and a slider 14 constrained by the locking guide groove 16 and the necking groove 15 and an emergency sleeve 13 coupled to the slider 14 are provided below the nut sleeve 9. The emergency sleeve 13 is axially constrained by the locking force spring 12 to the end face step of the nut sleeve 9, locking the screw nut 7 and the nut sleeve 9 together.

[0007] Furthermore, the inner sealing ring of the emergency sleeve 13 seals the outer ring surface of the nut sleeve 9, and is driven by the emergency release circuit of the high-pressure emergency medium to overcome the elastic force of the upper locking spring 12 to open the mechanical lock of the anti-jamming follower mechanism, and the emergency medium corresponding to the inner and outer circles of the emergency sleeve 13 enters the actuator to drive the mechanical lock to unlock, so that the screw nut 7 is disengaged from the nut sleeve 9, and the piston cylinder 6 is retracted.

[0008] Furthermore, when unlocking, the screw nut 7 and the nut sleeve 9 synchronously drive the locking sleeve 11 on the stepped cylinder to disengage from the lower end of the rigid locking ball 4, and the rigid locking ball 4 rolls along the guide hole 5 to disengage from the lock groove 3, and the end face of the nut sleeve 9 pushes the piston cylinder 6 to retract.

[0009] Furthermore, the high-pressure medium enters the inner cavity of the electromechanical actuator cylinder 1 from the emergency energy inlet 2 on the free end of the cylinder 1, and the high-pressure medium pushes the emergency sleeve 13 to overcome the elastic force of the upper locking spring 12 and disengage from the upper end of the slider 14. The slider 14 slides radially along the locking guide groove 16 and disengages from the necking groove 15, and the screw nut 7 is disengaged from the nut sleeve 9; the high-pressure medium pushes the stepped cylinder locking sleeve 11 to overcome the elastic force of the reset spring 10 and disengage from the lower end of the rigid locking ball 4, and the rigid locking ball 4 rolls along the guide hole 5 and disengages from the lock groove 3, and the high-pressure medium pushes the piston cylinder 6 to retract.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] The present invention utilizes an electromechanical actuator cylinder 1 connected to a servo motor shaft gear via a gear transmission mechanism, a lead screw drive pair 8 assembled within the transmission cavity of the cylinder 1 and meshing with the gear transmission mechanism, a piston cylinder 6 for telescopic movement of the cylinder 1, and an anti-jamming follower mechanism. The structure is simple, mechanically strong, and can withstand large steady and dynamic loads. This reduces vibration and noise, improving the working environment. The anti-jamming follower mechanism is formed by the outer annular surface of the lead screw nut 7 being fitted over the inner annular surface of the nut sleeve 9. A locking guide groove 16 is provided at the end of the nut sleeve 9 relative to a radially tapered groove 15 at the front of the lead screw nut 7. Below the nut sleeve 9, a slider 14 is provided, constrained by the locking guide groove 16 and the tapered groove 15, and an emergency sleeve 13 is coupled to the slider 14. The emergency sleeve 13 is axially constrained by a locking spring 12 to the end step of the nut sleeve 9, locking the lead screw nut 7 and the nut sleeve 9 together. This has a good installation and fixing structure, is simple and compact, occupies little space, and allows the screw nut 7 and the nut sleeve 9 to be locked together, and can be unlocked by a high-pressure medium, which can effectively isolate faults caused by the blockage of the screw pair.

[0012] The present invention designs a sealing structure on the inner and outer circles of the emergency sleeve 13, so that it can be driven by an emergency medium to open the mechanical lock of the anti-jamming follower mechanism. By designing a corresponding sealing structure on the inner and outer circles of the locking sleeve 11 on the stepped cylinder, it can be driven by an emergency medium to open the mechanical lock of the rigid locking ball 4. This ensures that when emergency operation is required, the emergency medium entering the actuator can drive the mechanical lock to unlock, disengage the screw nut 7 from the nut sleeve 9, and retract the piston cylinder 6, thereby solving the problem that conventional electromechanical actuators cannot solve the single-point failure of the screw pair being jammed.

[0013] The present invention adopts a free end of the piston head that is hollow and faces the cavity of the cylinder barrel 1. The screw is converted into mechanical energy of the nut sleeve 9 mounted on the outer ring surface through the screw nut 7 assembled in the hollow stepped hole of the piston head. The radial necking groove 15 at the front of the screw nut 7 corresponds to the locking guide groove 16 of the nut sleeve 9, and is constrained by the slider 14 provided under the nut sleeve 9. The slider 14 is coupled to the emergency sleeve 13, and the upper locking force spring 12 and the reset spring 10 that maintains the upper locking force are axially constrained on the end face of the hollow stepped hole of the piston head, the end face of the emergency sleeve 13, and the end face of the locking sleeve 11 of the stepped cylinder. The screw nut 7 drives the nut sleeve 9, pushing the locking sleeve 11 on the stepped cylinder to overcome the elastic force of the reset spring 10 and the upper locking force spring 12 to complete the mechanical locking or unlocking of the rigid locking ball 4. When the rigid locking ball 4 is located in the locking groove 3 on the inner wall of the inner ring surface of the cylinder 1, the lower end rests on the outer ring surface of the locking sleeve 11 on the stepped cylinder, and the mechanical locking of the rigid locking ball 4 is realized. When unlocking, the screw nut 7 and the nut sleeve 9 drive the locking sleeve 11 on the stepped cylinder to disengage from the lower end of the rigid locking ball 4, and the rigid locking ball 4 rolls along the guide hole 5 to disengage from the locking groove 3, and the end surface of the nut sleeve 9 pushes the piston cylinder 6 to retract.

[0014] The present invention adopts high-pressure medium to enter the inner cavity of the cylinder 1 of the electromechanical actuator from the emergency energy inlet 2 on the free end of the cylinder 1. The high-pressure medium pushes the emergency sleeve 13 to overcome the elastic force of the upper locking spring 12 and disengage from the upper end of the slider 14. The slider 14 slides radially along the locking guide groove 16 and disengages from the necking groove 15, and the screw nut 7 is disengaged from the nut sleeve 9; the high-pressure medium pushes the locking sleeve 11 of the stepped cylinder to overcome the elastic force of the reset spring 10 and disengage from the lower end of the rigid locking ball 4, and the rigid locking ball 4 rolls along the guide hole 5 and disengages from the locking groove 3, and the high-pressure medium pushes the piston cylinder 6 to retract, which effectively solves the problem that conventional dual-redundant electromechanical actuators still need to rely on electricity to achieve emergency retraction and extension but cannot solve the single-point failure problem of the screw pair being stuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below with reference to the accompanying drawings and examples, but the present invention is not limited to the scope of the embodiments described. All these concepts should be regarded as the content disclosed by this technology and the scope of protection of the present invention.

[0016] Figure 1 It is a schematic diagram of the locked state structure of the retracted inner lock emergency unlocking electromechanical actuator of the present invention.

[0017] Figure 2 yes Figure 1 Schematic diagram of the enlarged cross section.

[0018] In the figure: 1 cylinder, 2 emergency energy inlet, 3 lock groove, 4 rigid lock ball, 5 guide hole, 6 piston cylinder, 7 screw nut, 8 screw transmission pair, 9 nut sleeve, 10 return spring, 11 stepped cylinder locking sleeve, 12 locking force spring, 13 emergency sleeve, 14 slider, 15 necking groove, 16 locking guide groove. DETAILED DESCRIPTION

[0019] See Figure 1 . In the preferred embodiment described below, an internally locked emergency retraction and unlocking electromechanical actuator comprises: an electromechanical actuator cylinder 1 connected to the servo motor shaft gear through a gear transmission mechanism, a screw transmission pair 8 assembled in the transmission cavity of the cylinder 1 and meshing with the gear transmission mechanism, and a piston cylinder 6 and an anti-jamming follower mechanism for the cylinder 1 to perform telescopic movement, characterized in that: the piston head is hollow and faces the free end of the cylinder 1 cavity, the screw is converted into mechanical energy of the nut sleeve 9 mounted on the outer ring surface through the screw nut 7 assembled in the hollow stepped hole of the piston head, the radial necking groove 15 on the front of the screw nut 7 corresponds to the locking guide groove 16 of the nut sleeve 9, and is constrained by the slider 14 provided below the nut sleeve 9, and the slider 14 is coupled to the connected emergency sleeve 13, the upper locking force spring 12 and the return spring 10 that maintains the upper locking force are axially constrained on the end face of the hollow step hole of the piston head and the end face of the emergency sleeve 13 and the end face of the locking sleeve 11 of the stepped cylinder. The screw nut 7 drives the nut sleeve 9, and pushes the locking sleeve 11 of the stepped cylinder to overcome the elastic movement of the return spring 10 and the upper locking force spring 12, completing the mechanical switching of the rigid locking ball 4 to lock or unlock. The piston cylinder 6 is linearly retracted into the locking and unlocking positions, and the emergency energy inlet 2 on the communicating actuator is used for the emergency release circuit of the high-pressure medium. The return spring 10 pre-loaded inside the piston head is compressed, and the locking sleeve 11 and the emergency sleeve 13 of the stepped cylinder overcome the spring force to emergency disengage from the rigid locking ball 4, and the lock is emergency unlocked. The high-pressure medium pushes the piston cylinder 6 to retract.

[0020] The anti-jamming following mechanism includes: a fitted screw nut 7, a nut sleeve 9 fitted on the outer ring surface of the screw nut 7, an emergency sleeve 13 sealed on the outer ring surface of the nut sleeve 9, an upper locking force spring 12 constrained by the free end of the emergency sleeve 13, one end of the return spring 10 constrained on the outer ring surface of the upper locking force spring 12, and the other end constrained on the stepped cylinder locking sleeve 11 on the end face of the step hole in the piston head, a locking guide groove 16 arranged at a relative position between the nut sleeve 9 and the radial necking groove 15 at the front of the screw nut 7, a slider 14 constrained by the locking guide groove 16 and the necking groove 15, and the emergency sleeve 13 coupled and connected below the slider 14, the emergency slide 13 is axially constrained by the upper locking force spring 12 in the inner cylinder of the stepped cylinder locking sleeve 11, thereby forming an anti-jamming following mechanism that locks the screw nut 7 and the nut sleeve 9 together.

[0021] Example 1

[0022] The screw nut 7 and the nut sleeve 9 synchronously drive the locking sleeve 11 on the stepped cylinder to move left, compressing the reset spring 10 and the upper locking force spring 12, and the rigid locking ball 4 rolls along the guide hole 5. The rigid locking ball 4 disengages from the lock groove 3 and rolls to the shoulder cut angle bevel of the locking sleeve 11 on the stepped cylinder to unlock, and the end face of the nut sleeve 9 pushes the piston cylinder 6 to retract.

[0023] Example 2

[0024] When emergency unlocking and retraction of the piston cylinder are required, the high-pressure medium enters the inner cavity of the electromechanical actuator cylinder 1 from the emergency energy inlet 2 on the free end of the cylinder 1, pushing the emergency sleeve 13 to overcome the elastic force of the locking spring 12, and simultaneously pushing the stepped cylinder locking sleeve 11 to overcome the elastic force of the reset spring 10. The emergency sleeve 13 slides axially along the locking guide groove 16 and disengages from the necking groove 15. The rigid locking ball 4 rolls along the guide hole 5 to disengage from the lock groove 3 and rolls to the shoulder cut angle inclined surface of the stepped cylinder locking sleeve 11. The high-pressure medium pushes the piston cylinder 6 to emergency unlock and retract the piston cylinder.

[0025] According to any of the above exemplary embodiments, the screw transmission pair 8 rotates, reversely pushes the screw nut 7, and synchronously drives the nut sleeve 9, the piston cylinder 6 and the locking sleeve 11 on the step cylinder to move to the right, and the locking sleeve 11 on the step cylinder moves accordingly until the piston head reaches the step hole at the bottom end of the cylinder 1, the reset spring 10 and the locking force spring 12 release the spring force, and the locking sleeve 11 on the step cylinder pushes the rigid locking ball 4 to roll along the guide hole 5 on the piston head until it is pushed into the lock groove 3, so that the piston cylinder 6 is extended and locked, and the actuator cylinder 1 is locked again.

[0026] According to any of the above exemplary embodiments, when the piston barrel 6 is extended, the rigid locking ball 4 is located in the locking groove 3 and the steel ball guide hole 5 on the inner surface of the cylinder barrel 1, and the lower end rests on the outer ring surface of the locking sleeve 11 on the stepped barrel, thereby achieving locking. When emergency unlocking and retracting the piston barrel are required, the high-pressure emergency medium enters the inner cavity of the electromechanical actuator cylinder barrel 1 from the emergency energy inlet 2, pushing the emergency sleeve 13 to overcome the elastic force of the upper locking force spring 12 and disengage from the outer end of the slider 14, and the screw nut 7 is disengaged from the nut sleeve 9, thereby achieving complete disengagement of the screw nut 7 from the piston barrel 6; at the same time, the high-pressure emergency medium pushes the locking sleeve 11 on the stepped barrel to overcome the elastic force of the reset spring 10 and disengage from the lower end of the rigid locking ball 4 to move out of the gap of the stepped arm, so that the rigid locking ball 4 is driven by the piston barrel 6 to disengage from the locking groove 3, and the high-pressure emergency medium pushes the piston barrel 6 to retract.

[0027] For reference, in the exemplary embodiment, the rigid locking ball 4 is mounted within a guide hole 5 in the outer stepped ring of the piston head of the piston barrel 6. Its upper end is mounted within a locking groove 3 on the inner annular surface of the cylinder barrel 1, which has a diameter comparable to that of the rigid locking ball 4. Its lower end rests against the outer surface of the stepped locking sleeve 11. A slider 14 is mounted within a locking guide groove 16 of the nut sleeve 9, with one end embedded in a radially constricted groove 15 of the lead screw nut 7 and the other end resting against the inner surface of the emergency sleeve 13.

[0028] Although the embodiments of the present invention have been shown and described above and described in detail, the description of the above embodiments is only intended to facilitate understanding of the present invention. At the same time, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the contents of this specification should not be construed as limiting the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An internally locked emergency retraction and unlocking electromechanical actuator, comprising: An electromechanical actuator cylinder (1) connected to a servo motor shaft gear through a gear transmission mechanism, a screw transmission pair (8) assembled in a transmission cavity of the cylinder (1) and meshed with the gear transmission mechanism, a piston cylinder (6) and an anti-jamming follower mechanism for the cylinder (1) to perform telescopic movement, characterized in that: the piston head is hollow and faces the free end of the cylinder (1) cavity, the screw is converted into mechanical energy of a nut sleeve (9) mounted on the outer ring surface through a screw nut (7) assembled in a hollow stepped hole of the piston head, the radial necking groove (15) at the front of the screw nut (7) corresponds to the locking guide groove (16) of the nut sleeve (9), and is constrained by a slider (14) provided below the nut sleeve (9), the slider (14) is coupled to the connected emergency sleeve (13), and the locking force spring (12) and the upper The reset spring (10) of the locking force is axially constrained on the end face of the hollow step hole of the piston head and the end face of the emergency sleeve (13) and the end face of the locking sleeve (11) on the stepped cylinder. The screw nut (7) drives the nut sleeve (9) to push the locking sleeve (11) on the stepped cylinder to overcome the elastic force of the reset spring (10) and the upper locking force spring (12), thereby completing the mechanical switching of the rigid locking ball (4) to lock or unlock. The piston cylinder (6) is linearly retracted to the locking and unlocking positions, and the emergency energy inlet (2) on the communicating actuator is connected to the high-pressure medium emergency release circuit. The reset spring (10) pre-pressed inside the piston head is compressed, and the locking sleeve (11) and the emergency sleeve (13) on the stepped cylinder overcome the spring force to emergency disengage from the rigid locking ball (4). The lock is unlocked in an emergency, and the high-pressure medium pushes the piston cylinder (6) to retract. When emergency unlocking and retraction of the piston cylinder is required, the high-pressure emergency medium enters the inner cavity of the electromechanical actuator cylinder (1) from the emergency energy inlet (2), pushes the emergency sleeve (13) to overcome the elastic force of the upper locking spring (12), and disengages from the outer end of the slider (14), and the screw nut (7) is separated from the nut sleeve (9), thereby achieving complete separation of the screw nut (7) and the piston cylinder (6); at the same time, the high-pressure emergency medium pushes the locking sleeve (11) on the stepped cylinder to overcome the elastic force of the return spring (10), and disengages from the lower end of the rigid locking ball (4) to move out of the gap of the stepped arm, so that the rigid locking ball (4) is driven by the piston cylinder (6) to disengage from the lock groove (3), and the high-pressure emergency medium pushes the piston cylinder (6) to retract.

2. The electromechanical actuator with an internal lock type emergency retraction and unlocking according to claim 1, characterized in that: When the rigid locking ball (4) is located in the locking groove (3) on the inner wall of the inner ring surface of the cylinder barrel (1), and the lower end thereof rests against the outer ring surface of the locking sleeve (11) on the stepped barrel, the mechanical locking of the rigid locking ball (4) is realized. When unlocking, the screw nut (7) and the nut sleeve (9) drive the locking sleeve (11) on the stepped barrel to escape from the lower end of the rigid locking ball (4), and the rigid locking ball (4) rolls along the guide hole (5) and escapes from the locking groove (3), and the end surface of the nut sleeve (9) pushes the piston barrel (6) to retract.

3. The electromechanical actuator with internal locking emergency retraction and unlocking according to claim 1, characterized in that: The anti-jamming follower mechanism comprises: a set screw nut (7), a nut sleeve (9) set on the outer ring surface of the screw nut (7), an emergency sleeve (13) with a ring seal on the outer ring surface of the nut sleeve (9), a locking spring (12) constrained by the free end of the emergency sleeve (13), one end of the return spring (10) is constrained on the outer ring surface of the locking spring (12), and the other end is constrained on the stepped tube locking sleeve (11) on the end surface of the step hole in the piston head, a locking guide groove (16) set at a relative position between the nut sleeve (9) and the radial necking groove (15) at the front of the screw nut (7), and a slider (14) constrained by the locking guide groove (16) and the necking groove (15) and coupled to the lower side of the emergency sleeve (13).

4. The electromechanical actuator with internal locking emergency retraction and unlocking according to claim 1, characterized in that: The rigid locking ball (4) is located in the locking groove (3) on the inner wall of the inner ring surface of the cylinder (1), and the lower end is against the outer ring surface of the locking sleeve (11) on the stepped cylinder, so as to realize the mechanical locking of the rigid locking ball (4).

5. The electromechanical actuator with internal locking emergency retraction and unlocking according to claim 1, characterized in that: The screw nut (7) and the nut sleeve (9) synchronously drive the locking sleeve (11) on the stepped cylinder to move leftward, compressing the reset spring (10) and the upper locking force spring (12), and the rigid locking ball (4) rolls along the guide hole (5). The rigid locking ball (4) is separated from the locking groove (3) and rolls to the shoulder cut angle inclined surface of the locking sleeve (11) on the stepped cylinder to unlock, and the end surface of the nut sleeve (9) pushes the piston cylinder (6) to retract.

6. The electromechanical actuator with an internal lock and emergency retraction and unlocking function according to claim 1, wherein: When emergency unlocking and retraction of the piston cylinder is required, high-pressure medium enters the inner cavity of the electromechanical actuator cylinder barrel (1) from the emergency energy inlet (2) on the free end of the cylinder barrel (1), pushes the emergency sliding sleeve (13) to overcome the elastic force of the upper locking force spring (12), and simultaneously pushes the locking sliding sleeve (11) of the stepped cylinder to overcome the elastic force of the return spring (10), the slider (14) slides axially along the locking guide groove (16) and disengages from the necking groove (15), the rigid locking ball (4) rolls along the guide hole (5) to disengage from the locking groove (3), and rolls to the shoulder cut angle inclined surface of the locking sliding sleeve (11) of the stepped cylinder, and the high-pressure medium pushes the piston cylinder (6) to emergency unlock and retract the piston cylinder.

7. The electromechanical actuator with an internal lock and emergency retraction and unlocking function according to claim 1, wherein: When the piston cylinder (6) is extended, the rigid locking ball (4) is located in the locking groove (3) and the steel ball guide hole (5) on the inner surface of the cylinder cylinder (1), and the lower end rests on the outer ring surface of the locking sleeve (11) on the stepped cylinder, so that the piston cylinder (6) is locked in the extended position.

8. The electromechanical actuator with an internal lock and emergency retraction and unlocking function according to claim 1, wherein: The rigid locking ball (4) is installed in the guide hole (5) on the outer ring step cylinder of the piston head of the piston cylinder (6), the upper end of which is installed in the locking groove (3) on the inner ring surface of the cylinder (1) with a diameter equivalent to that of the rigid locking ball (4), and the lower end of which is against the outer ring surface of the locking sleeve (11) on the stepped cylinder; the slider (14) is installed in the locking guide groove (16) of the nut sleeve (9), one end of which is embedded in the radial necking groove (15) of the screw nut (7), and the other end of which is against the inner ring surface of the emergency sleeve (13).

9. The electromechanical actuator with internal locking emergency retraction and unlocking according to claim 1, characterized in that: The screw drive pair (8) rotates, pushing the screw nut (7) in reverse, and synchronously drives the nut sleeve (9), the piston cylinder (6) and the step cylinder locking sleeve (11) to move right, and the step cylinder locking sleeve (11) moves accordingly until the piston head reaches the step hole at the bottom end of the cylinder barrel (1). The return spring (10) and the upper locking force spring (12) release the spring force, and the step cylinder locking sleeve (11) pushes the rigid locking ball (4) to roll along the guide hole (5) of the piston head until it reaches the locking groove (3), so that the piston cylinder (6) is extended and locked, and the actuator cylinder barrel (1) is locked again.

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