actuator

Abstract

This invention discloses an actuator, including a locking linkage mechanism, comprising a retainer connected to a lead screw nut, an upper bushing abutting against the retainer at one end, a lower bushing opposite to the upper bushing, an elastic unit disposed between the upper and lower bushings, multiple upper locking blocks disposed at the location of the upper bushing, a lower locking block disposed at the location of the lower bushing, and a spring bushing. An outer cylinder is provided with upper locking grooves and lower locking grooves that cooperate with the upper and lower locking blocks. When the upper and lower locking blocks form a limiting fit with the upper and lower bushings, the upper and lower locking blocks can extend into the corresponding upper and lower locking grooves. When the upper and lower locking blocks move into the clearance space, they can disengage from the upper and lower locking grooves. This invention solves the problems of low actuator reliability and short lead screw service life caused by the lead screw bearing locking loads.

Description

Technical Field

[0001] This invention belongs to the field of mechanical equipment actuation technology, specifically relating to actuators. Background Technology

[0002] With the maturity of my country's motor and electronic technologies, electromechanical actuators are widely used in aerospace vehicles, especially in the landing gear and door motion actuators of unmanned aerial vehicles (UAVs). As a core component of the landing gear, the electromechanical actuator determines whether the aircraft can take off, land, and fly safely. Typically, an electromechanical actuator, as a linear motion actuator, mainly includes components such as a driver, drive motor, transmission mechanism, reduction mechanism, torque conversion and transmission unit, motion position detection and feedback element, and self-locking device. The lead screw pair in the torque conversion and transmission unit converts rotational motion into linear motion to achieve the linear extension or retraction of the actuator's piston rod. Lead screws are commonly classified as ball screws, planetary ball screws, and trapezoidal screws. As a precision transmission mechanism, the service life of the lead screw is closely related to the workload.

[0003] Existing electromechanical actuators typically include a locking device. This device prevents external forces from causing movement when the actuator stops at a designated position, thus ensuring the locking of landing gear and doors. Locking devices usually include components such as ball locks, locking grooves, conical pistons, and springs. However, existing conventional locking devices consume a lot of energy and are unable to withstand the enormous loads during aircraft landing, and may even jam during retraction or extension. Furthermore, the locking device transmits the locking load of the electromechanical actuator to the lead screw within the actuator at the designated position, causing the lead screw pair to bear a load exceeding its rated load, leading to damage to the lead screw raceways. This reduces the reliability of the electromechanical actuator and could even cause the aircraft to crash. Summary of the Invention

[0004] The purpose of this invention is to provide an actuator that solves the problems of low reliability and short service life of existing actuators in the locked state due to the lead screw bearing the locking load.

[0005] This invention is achieved through the following technical solution:

[0006] Actuators, including:

[0007] The outer cylinder has an end cap assembly at one end;

[0008] The transmission mechanism includes a lead screw rotatably disposed inside the outer cylinder and a lead screw nut disposed on the lead screw;

[0009] The piston rod is located at one open end of the outer cylinder and includes a cylindrical sliding part that slides in conjunction with the outer cylinder.

[0010] The locking linkage mechanism includes a retainer connected to a lead screw nut, an upper bushing abutting against the retainer at one end, a lower bushing opposite to the upper bushing, an elastic unit disposed between the upper and lower bushings, multiple upper locking blocks fitted at the position of the upper bushing, a lower locking block fitted at the position of the lower bushing, and a spring bushing. Limiting engagements are formed between the upper locking blocks and the upper bushing, and between the lower locking blocks and the lower bushing, respectively, to restrict the movement of the upper locking blocks relative to the upper bushing in the direction of piston rod extension, and to limit... The lower locking block moves relative to the lower bushing in the direction of piston rod retraction, and a clearance space is formed between the upper locking block and the upper bushing, and between the lower locking block and the lower bushing, at the limiting engagement position, allowing the upper locking block and the lower locking block to move radially toward the center of the outer cylinder. The spring bushing is connected to the lower bushing at one end and to the cage at the other end. The cage is provided with a drive part, and the sliding part is provided with a limiting groove. The drive part extends into the limiting groove, and when the drive part and the end face of the limiting groove are in contact, the piston rod can be driven to move.

[0011] The outer cylinder is provided with an upper locking groove and a lower locking groove that cooperate with the upper locking block and the lower locking block; the sliding part is provided with a limiting hole that cooperates with the upper locking block and the lower locking block, and the upper locking block and the lower locking block are respectively fitted into the corresponding limiting hole; when the upper locking block and the lower locking block form a limiting fit with the upper bushing and the lower bushing, the upper locking block and the lower locking block can extend into the upper locking groove and the lower locking groove respectively; when the upper locking block and the lower locking block move into the clearance space, the upper locking block and the lower locking block can disengage from the upper locking groove and the lower locking groove respectively.

[0012] In some embodiments, one end of the outer cylinder opening is provided with an inwardly extending limiting flange, which is used to cooperate with the end face of the sliding part to restrict the movement of the piston rod in the axial direction.

[0013] In some embodiments, one end of the spring bushing is provided with a flange that mates with the lower bushing and forms a limiting fit with the end face of the lower bushing, and the other end of the spring bushing passes through the lower bushing and the upper bushing in sequence and is connected to the cage.

[0014] In some embodiments, the upper bushing and the lower bushing are fitted onto the spring bushing.

[0015] In some embodiments, the upper bushing and the lower bushing are disposed within the sliding portion and form a sliding fit with the sliding portion.

[0016] In some embodiments, a load-bearing component is also included. The lead screw is rotatably connected to the outer cylinder through the load-bearing component. One end of the load-bearing component abuts against the end cap assembly, and the other end is disposed in the direction of the piston rod. When the upper locking block falls into the upper locking groove, the end face of the sliding part abuts against the end face of the load-bearing component.

[0017] In some embodiments, the load-bearing component includes a bearing and a bearing housing. One end of the bearing abuts against the end cap assembly, and the other end is disposed on the bearing housing. One end of the bearing housing is disposed toward the piston rod and is used to limit the piston rod.

[0018] In some embodiments, the lead screw drives the upper bushing and lower bushing to move through the lead screw nut, and after the upper locking block and lower locking block move to the locking position, the elastic unit applies a reverse force to the lead screw nut that can make the lead screw rotate, so that the drive part is separated from the end face of the limiting slide groove.

[0019] In some embodiments, the system further includes a motor connected to a lead screw via a transmission assembly, which drives the lead screw to rotate and can drive the motor to rotate in the opposite direction when the lead screw rotates.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] This invention employs a locking linkage mechanism. While locking the position of the piston rod, it also applies a force to the lead screw nut via an elastic unit when the actuator is locked in the extended and retracted positions. This force causes the lead screw to rotate in the opposite direction, driving the cage to move and maintaining a certain gap between the cage and the piston rod. As a result, the locking load of the actuator in the locked state is transferred to the outer cylinder or load-bearing component. The lead screw only bears the driving load of the extension and retraction movements, providing effective protection for the lead screw, improving the reliability of the actuator, and extending the service life of the lead screw and lead screw nut. Furthermore, this actuator has a simple structure and is suitable for actuators of various sizes. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a cross-sectional view of the actuator in the retracted position locked in an embodiment of the present invention.

[0024] Figure 2 for Figure 1 Partial schematic diagram of point I in the middle.

[0025] Figure 3 for Figure 1 Partial schematic diagram of section II in the middle.

[0026] Figure 4 This is a schematic diagram of the structure of the actuator in the retracted position with no clearance between the driving part and the upper end face of the limiting slide groove in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of the engagement state between the lower locking block and the lower bushing when the actuator is in the retracted position in an embodiment of the present invention.

[0028] Figure 6 This is a cross-sectional schematic diagram of the actuator locked in the extended position in an embodiment of the present invention.

[0029] Figure 7 for Figure 6 Partial schematic diagram of section III.

[0030] Figure 8 for Figure 6 A partial schematic diagram of point IV in the middle.

[0031] Figure 9 This is a schematic diagram of the structure of the actuator in the extended position with no clearance between the driving part and the lower end face of the limiting slide groove in an embodiment of the present invention.

[0032] Figure 10 This is a schematic diagram of the engagement state between the lower locking block and the lower bushing when the actuator is in the extended position in an embodiment of the present invention.

[0033] Wherein: 1-motor, 2-transmission assembly, 3-end cover assembly, 4-bearing assembly, 5-lead screw, 6-lead screw nut, 7-cage, 8-upper locking block, 9-upper bushing, 10-elastic unit, 11-lower bushing, 12-spring bushing, 13-piston rod, 14-outer cylinder, 141-upper locking groove, 142-lower locking groove, 15-lower locking block, 16-drive unit, 17-limiting slide groove. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0035] Example 1

[0036] Actuator, refer to Figure 1 and Figure 6 ,include:

[0037] The outer cylinder 14 has an end cap assembly 3 at one end;

[0038] The transmission mechanism includes a lead screw 5 rotatably disposed inside the outer cylinder and a lead screw nut 6 disposed on the lead screw 5;

[0039] The piston rod 13 is located at one end of the opening of the outer cylinder and includes a cylindrical sliding part that slides in cooperation with the outer cylinder 14.

[0040] The locking linkage mechanism includes a retainer 7 connected to a lead screw nut 6 via a thread, an upper bushing 9 abutting against the retainer 7 at one end, a lower bushing 11 opposite to the upper bushing 9, an elastic unit 10 disposed between the upper bushing 9 and the lower bushing 11, multiple upper locking blocks 8 fitted at the position of the upper bushing 9, a lower locking block 15 fitted at the position of the lower bushing 11, and a spring bushing 12. Limiting engagements are formed between the upper locking blocks 8 and the upper bushing 9, and between the lower locking blocks 15 and the lower bushing 11, respectively, to restrict the movement of the upper locking blocks 8 relative to the upper bushing 9 in the direction of piston rod extension. The movement of the lower locking block 15 relative to the lower bushing 11 in the direction of piston rod retraction is restricted. At the limiting engagement position, a clearance space is formed between the upper locking block 8 and the upper bushing 9, and between the lower locking block 15 and the lower bushing 11, allowing the upper locking block 8 and the lower locking block 15 to move radially toward the center of the outer cylinder. The spring bushing 12 is connected to the lower bushing 11 at one end and to the retainer 7 at the other end. The retainer is provided with a drive part 16, and the sliding part is provided with a limiting groove 17. The drive part 16 is engaged and extends into the limiting groove. When the drive part 16 and the end face of the limiting groove are engaged, the piston rod 13 can be driven to move.

[0041] The outer cylinder 14 is provided with an upper locking groove 141 and a lower locking groove 142 that cooperate with the upper locking block 8 and the lower locking block 15; the sliding part is provided with a limiting hole that cooperates with the upper locking block 8 and the lower locking block 15, and the upper locking block 8 and the lower locking block 15 are respectively fitted into the corresponding limiting hole; when the upper locking block 8 and the lower locking block 15 form a limiting fit with the upper bushing 9 and the lower bushing 11, the upper locking block 8 and the lower locking block 15 can extend into the upper locking groove and the lower locking groove respectively; when the upper locking block 8 and the lower locking block 15 move into the clearance space, the upper locking block 8 and the lower locking block 15 can disengage from the upper locking groove and the lower locking groove respectively.

[0042] By employing a locking linkage mechanism, the position of the piston rod is locked. When the actuator is locked in the extended and retracted positions, the elastic unit 10 applies a force to the lead screw nut 6, causing the lead screw to rotate in the opposite direction. This drives the cage 7 to move, maintaining a certain gap between the cage 7 and the piston rod 13. As a result, the locking load of the actuator in the locked state is transferred to the outer cylinder 14 or the load-bearing component 4. The lead screw 5 only bears the driving load of the extension and retraction actions, providing effective protection for the lead screw 5, improving the reliability of the actuator, and extending the service life of the lead screw and lead screw nut.

[0043] The elastic element 10 can be a metal spring.

[0044] In some embodiments, one end of the outer cylinder opening is provided with an inwardly extending limiting flange, which is used to cooperate with the end face of the sliding part to restrict the movement of the piston rod in the axial direction.

[0045] In some embodiments, one end of the spring bushing is provided with a flange that mates with the lower bushing 11 and forms a limiting fit with the end face of the lower bushing, and the other end of the spring bushing passes through the lower bushing 11 and the upper bushing 9 in sequence and is connected to the retainer 7.

[0046] In some embodiments, the upper bushing 9 and the lower bushing 11 are fitted onto the spring bushing.

[0047] In some embodiments, the upper bushing 9 and the lower bushing 11 are disposed within the sliding portion and form a sliding fit with the sliding portion.

[0048] In some embodiments, a load-bearing component 4 is also included. The lead screw 5 is rotatably connected to the outer cylinder 14 through the load-bearing component 4. One end of the load-bearing component abuts against the end cap assembly 3, and the other end is set towards the piston rod. When the upper locking block 8 falls into the upper locking groove, the end face of the sliding part abuts against the end face of the load-bearing component. The load-bearing component 4 is interference-fitted with the head of the lead screw and is axially positioned and pressed by the end face of the outer cylinder and the end cap assembly.

[0049] In some embodiments, the load-bearing component 4 includes a bearing and a bearing housing. One end of the bearing abuts against the end cap assembly 3, and the other end is disposed on the bearing housing. One end of the bearing housing is disposed in the direction of the piston rod and is used to limit the piston rod 13.

[0050] In some embodiments, the lead screw 5 drives the upper bushing 9 and the lower bushing 11 to move through the lead screw nut 6, and after the upper locking block 8 and the lower locking block 15 move to the locking position, the elastic unit 10 applies a reverse force to the lead screw nut 6 that can make the lead screw 5 rotate, so that the drive part 16 is separated from the end face of the limiting slide groove.

[0051] In some embodiments, the system further includes a motor 1, which is connected to the lead screw 5 via a transmission assembly 2 to drive the lead screw 5 to rotate, and can drive the motor to rotate in the opposite direction when the lead screw rotates.

[0052] In some embodiments, the upper locking block 8 and the lower locking block 15 are circumferentially distributed along the limiting holes on the sliding part, thereby improving the load-bearing capacity of the locking structure and ensuring the effectiveness of locking the actuator in the limited position.

[0053] The working motion process of the above actuator includes:

[0054] 1) The process of the actuator changing from the retracted locked state to the extended locked state.

[0055] When the actuator is in the retracted position and unlocked, refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 The motor 1 drives the lead screw 5 to rotate, the lead screw 5 drives the lead screw nut 6 to move and push the retainer 7 to move in the extension direction, so that the upper bushing 9 moves axially by A, where A is the distance between the drive part 16 of the retainer and the lower end face of the limiting slide groove.

[0056] Upper bushing 9 compresses elastic unit 10;

[0057] When the drive unit 16 moves to abut against the lower end face of the limiting slide groove and applies a force in the extension direction to the piston rod 13, the upper locking block 8 moves radially under the action of the piston rod, disengages from the upper locking groove, and is placed in the clearance space of the upper bushing, thus unlocking the upper locking block 8; at this time, the distance between the upper locking block 8 and the upper bushing 9 is C.

[0058] The drive unit 16 pushes the piston rod 13 to move in the extension direction. When the lower locking block 15 moves to the position of the lower locking groove, the elastic unit 10 pushes the lower bushing 11. Under the action of the lower bushing, the lower locking block 15 is pushed to pop out radially and extend into the lower locking groove, thereby locking the actuator in the extension position.

[0059] During this process, the elastic unit 10 pushes the lower bushing 11 to move a distance of B; at the same time, the elastic unit 10 applies a force to the upper bushing 9 in the retraction direction, and acts on the lead screw nut 6, driving the lead screw 5 to rotate in the opposite direction, causing the lead screw nut 6 to move in the retraction direction by C, so that the upper bushing 9 moves to the position of abutting against the upper locking block 8, and C is less than A; at this time, there is a certain gap between the drive part 16 of the retainer and the upper and lower end faces of the limiting slide groove.

[0060] At this time, when the piston rod 13 is subjected to tensile load, the end face of the sliding part of the piston rod abuts against the limiting flange of the outer cylinder, transferring the tensile load to the end cover assembly 3, so that the lead screw 5 and the lead screw nut 6 are not subjected to tensile load.

[0061] When the piston rod 13 is subjected to a compressive load, since there is a gap D between the drive part 16 and the lower end face of the limiting slide groove, the lower locking block 15 locks the position of the piston rod through the cooperation between the lower locking block 15 and the lower locking groove 142, and transmits the compressive load to the end cover assembly 3 through the outer cylinder 14, so that the lead screw 5 and the lead screw nut 6 are not subjected to a compressive load.

[0062] 2) The process of the actuator changing from the extended locked state to the retracted locked state.

[0063] When the actuator is in the extended position and then retracts, refer to Figure 6 , Figure 7 , Figure 8 , Figure 9and Figure 10 The screw nut 6 is driven to retract by reversing the screw, which in turn drives the retainer 7 to move in the retraction direction. When the retainer moves, it drives the spring bushing 12 to move, causing the lower bushing 11 to move axially by E, where E is the distance between the drive part 16 of the retainer and the upper end face of the limiting slide groove.

[0064] Lower bushing 11 compresses elastic unit 10;

[0065] When the drive unit 16 moves to abut against the upper end face of the limiting slide groove and applies a force in the retraction direction to the piston rod 13, the lower locking block 15 moves radially under the action of the piston rod, disengages from the lower locking groove, and is placed in the clearance space of the lower bushing, thus unlocking the lower locking block 15; at this time, the distance between the lower locking block 15 and the lower bushing 11 is G.

[0066] The drive unit 16 drives the piston rod 13 to move in the retraction direction. When the upper locking block 8 moves to the position of the upper locking groove, the elastic unit 10 pushes the upper bushing 9. Under the action of the upper bushing, the upper locking block 8 is pushed to pop out radially and extend into the upper locking groove, thereby realizing the locking of the actuator in the retracted position.

[0067] During this process, the elastic unit 10 pushes the upper bushing 9 to move a distance of F; at the same time, the elastic unit 10 applies a force to the lower bushing 11 in the extension direction, which acts on the lead screw nut 6, driving the lead screw to rotate in the opposite direction, causing the lead screw nut 6 to move in the extension direction by G, so that the lower bushing 11 moves to the position where the lower locking block abuts, and G is less than E; at this time, there is a certain gap between the drive part 16 of the retainer and the lower end face and the upper end face of the limiting slide groove.

[0068] At this time, when the piston rod 13 is subjected to tensile load, the tensile load is transferred to the end cover assembly 3 through the locking engagement between the upper locking block 8 and the upper locking groove 141. Since there is a gap H between the drive part 16 and the upper end face of the limit slide groove, the tensile load will not be transferred to the lead screw nut through the retainer 7, so that the lead screw 5 and the lead screw nut 6 are not subjected to tensile load.

[0069] When the piston rod 13 is subjected to a compressive load, the piston rod 13 abuts against the load-bearing component 4, and the compressive load is transmitted to the end cover component 3 through the load-bearing component 4, so that the lead screw 5 and the lead screw nut 6 are not subjected to a compressive load.

[0070] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An actuator, characterized in that, include: The outer cylinder has an end cap assembly at one end; The transmission mechanism includes a lead screw rotatably disposed inside the outer cylinder and a lead screw nut disposed on the lead screw; A piston rod is disposed at one open end of the outer cylinder and includes a cylindrical sliding part, which is slidably engaged with the outer cylinder. The locking linkage mechanism includes a retainer connected to a lead screw nut, an upper bushing abutting against the retainer at one end, a lower bushing opposite to the upper bushing, an elastic unit disposed between the upper and lower bushings, multiple upper locking blocks fitted at the position of the upper bushing, a lower locking block fitted at the position of the lower bushing, and a spring bushing. Limiting engagements are formed between the upper locking blocks and the upper bushing, and between the lower locking blocks and the lower bushing, respectively, to restrict the movement of the upper locking blocks relative to the upper bushing in the direction of piston rod extension and to restrict the movement of the lower locking blocks. The block moves relative to the lower bushing in the direction of piston rod retraction, and a clearance space is formed between the upper locking block and the upper bushing, and between the lower locking block and the lower bushing, at the limiting engagement position, allowing the upper locking block and the lower locking block to move radially toward the center of the outer cylinder. The spring bushing is connected to the lower bushing at one end and to the retainer at the other end. The retainer is provided with a driving part, and the sliding part is provided with a limiting slide groove. The driving part extends into the limiting slide groove, and when the driving part and the end face of the limiting slide groove abut against each other, the piston rod can be driven to move. The outer cylinder is provided with an upper locking groove and a lower locking groove that cooperate with the upper locking block and the lower locking block; the sliding part is provided with a limiting hole that cooperates with the upper locking block and the lower locking block, and the upper locking block and the lower locking block are respectively fitted into the corresponding limiting hole; when the upper locking block and the lower locking block form a limiting fit with the upper bushing and the lower bushing, the upper locking block and the lower locking block can extend into the upper locking groove and the lower locking groove respectively; when the upper locking block and the lower locking block move into the clearance space, the upper locking block and the lower locking block can disengage from the upper locking groove and the lower locking groove respectively.

2. The actuator according to claim 1, characterized in that, One end of the outer cylinder opening is provided with an inwardly extending limiting flange, which is used to cooperate with the end face of the sliding part to restrict the movement of the piston rod in the axial direction.

3. The actuator according to claim 1, characterized in that, One end of the spring bushing is provided with a flange that mates with the lower bushing and forms a limiting fit with the end face of the lower bushing. The other end of the spring bushing passes through the lower bushing and the upper bushing in sequence and is connected to the cage.

4. The actuator according to claim 3, characterized in that, The upper bushing and lower bushing are fitted onto the spring bushing.

5. The actuator according to claim 1 or 4, characterized in that, The upper bushing and lower bushing are disposed inside the sliding part and form a sliding fit with the sliding part.

6. The actuator according to claim 1, characterized in that, It also includes a load-bearing component, the lead screw is rotatably connected to the outer cylinder through the load-bearing component, one end of the load-bearing component abuts against the end cap assembly, and the other end is set towards the piston rod. When the upper locking block falls into the upper locking groove, the end face of the sliding part abuts against the end face of the load-bearing component.

7. The actuator according to claim 6, characterized in that, The load-bearing component includes a bearing and a bearing housing. One end of the bearing abuts against the end cover assembly, and the other end is disposed on the bearing housing. One end of the bearing housing is disposed in the direction of the piston rod and is used to limit the piston rod.

8. The actuator according to claim 1 or 6, characterized in that, The lead screw drives the upper and lower bushings to move through the lead screw nut, and after the upper and lower locking blocks move to the locking position, the elastic unit applies a reverse force to the lead screw nut, which can make the lead screw rotate, so that the drive part separates from the end face of the limiting slide groove.

9. The actuator according to claim 8, characterized in that, It also includes a motor, which is connected to a lead screw via a transmission assembly to drive the lead screw to rotate, and the lead screw can drive the motor to rotate in the opposite direction when it rotates.

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