Actuator

Abstract

The invention discloses an actuator which comprises a locking linkage mechanism. Comprising a retainer connected with a lead screw nut, an upper bush with one end abutting against the retainer, a lower bush arranged opposite to the upper bush, an elastic unit arranged between the upper bush and the lower bush, and a plurality of upper locking blocks arranged at the position where the upper bush is located in a matched mode. The upper locking block and the lower locking block are arranged on the outer cylinder in a matched mode, the lower locking block and the spring bushing are arranged at the position where the lower bushing is located in a matched mode, and an upper locking groove and a lower locking groove which are matched with the upper locking block and the lower locking block are formed in the outer cylinder. The upper locking block and the lower locking block can correspondingly stretch into the upper locking groove and the lower locking groove, and when the upper locking block and the lower locking block move into the receding space, the upper locking block and the lower locking block can be disengaged from the upper locking groove and the lower locking groove. The problems that the reliability of an actuator is low and the service life of a lead screw is short due to the fact that the lead screw bears a locking load are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical equipment actuation, and in particular relates to an actuator. Background Art

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

[0003] Existing electromechanical actuators usually have built-in locking devices. When the locking device stops at a limited position, it can prevent external force from causing movement, thereby ensuring the locking of the landing gear and the cabin door. The locking device usually includes components such as a steel ball lock, a lock groove, a tapered piston and a spring. However, the existing conventional locking devices consume a lot of energy and are difficult to withstand the huge load when the aircraft lands, and may even get stuck during the retraction and extension process; at the same time, the locking device transmits the locking load of the electromechanical actuator through the actuator to the lead screw at a limited position, causing the load on the lead screw pair to exceed the rated load, resulting in damage to the lead screw raceway, thereby reducing the reliability of the electromechanical actuator and even causing the aircraft to crash. Summary of the invention

[0004] The object of the present invention is to provide an actuator to solve the problem that the reliability of the actuator is low and the service life of the lead screw is short due to the locking load borne by the lead screw in the locked state of the existing actuator.

[0005] The present invention is achieved through the following technical solutions:

[0006] Actuators, including:

[0007] An outer cylinder, one end of which is provided with an end cap assembly;

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

[0009] The piston rod is arranged at one end of the opening of the outer tube, and comprises a sliding portion in a cylindrical shape, and the sliding portion is slidably matched with the outer tube;

[0010] The locking linkage mechanism includes a retaining frame connected to the screw nut, an upper bushing abutting the retaining frame at one end, a lower bushing arranged opposite to the upper bushing, an elastic unit arranged between the upper bushing and the lower bushing, a plurality of upper locking blocks arranged at the position of the upper bushing, a lower locking block and a spring bushing arranged at the position of the lower bushing, and a limit fit is formed between the upper locking block and the upper bushing, and between the lower locking block and the lower bushing, respectively, for limiting the movement of the upper locking block relative to the upper bushing in the direction of extending the piston rod and limiting The lower locking block is controlled to move relative to the lower bushing in the direction of retraction of the piston rod, 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 matching position, which can allow the upper locking block and the lower locking block to move toward the center of the outer cylinder in the radial direction. The spring bushing is connected to the lower bushing at one end and to the retaining frame at the other end; a driving part is provided on the retaining frame, and a limiting slot is provided on the sliding part. The driving part cooperates and extends into the limiting slot, and when the driving part abuts and cooperates with the end surface of the limiting slot, the piston rod can be driven to move;

[0011] The outer cylinder is provided with an upper lock groove and a lower lock groove that cooperate with the upper lock block and the lower lock block; the sliding part is provided with a limiting hole that cooperates with the upper lock block and the lower lock block, and the upper lock block and the lower lock block are respectively arranged in the corresponding limiting holes; when the upper lock block, the lower lock block and the upper bushing, the lower bushing form a limiting match, the upper lock block and the lower lock block can extend into the upper lock groove and the lower lock groove respectively, and when the upper lock block and the lower lock block move into the make way space, the upper lock block and the lower lock block can escape from the upper lock groove and the lower lock groove.

[0012] In some embodiments, an inwardly extending limiting flange is provided at one end of the outer tube opening, which is used to cooperate with the end surface of the sliding portion to limit 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 cooperates 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 retaining frame.

[0014] In some embodiments, the upper bushing and the lower bushing are cooperatively mounted on the spring bushing.

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

[0016] In some embodiments, it also includes a load-bearing component, and the screw is rotatably connected to the outer cylinder through the load-bearing component. One end of the load-bearing component abuts against the end cover component, and the other end is set 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 seat, one end of the bearing abuts against the end cover assembly, and the other end is arranged on the bearing seat, and one end of the bearing seat is arranged toward the piston rod to limit the piston rod.

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

[0019] In some embodiments, a motor is also included, which is connected to the lead screw through a transmission assembly and is used to drive the lead screw to rotate, and the lead screw can drive the motor to rotate in the reverse direction when rotating.

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

[0021] The present invention adopts a locking linkage mechanism, which can lock the position of the piston rod while enabling the actuator to be locked in the extended position and the retracted position. The elastic unit applies a force to the lead screw nut to cause the lead screw to rotate in the opposite direction, driving the retaining frame to move, so that a certain gap is maintained between the retaining frame and the piston rod, so that the locking load of the actuator in the locked state is transmitted to the outer cylinder or the load-bearing component, and the lead screw only bears the driving load of the extension and retraction actions, which can provide effective protection for the lead screw, improve the reliability of the actuator, and extend the service life of the lead screw and the lead screw nut. The actuator has a simple structure and is suitable for actuators of various sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It is a cross-sectional schematic diagram of the actuator locked in the retracted position according to the 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 point II in the middle.

[0026] Figure 4 It is a schematic structural diagram of a clearance-free fit state between the driving portion and the upper end surface of the limiting slide groove when the actuator is in the retracted position in an embodiment of the present invention.

[0027] Figure 5 It is a structural schematic diagram of the matching 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 It is a cross-sectional schematic diagram of the actuator locked in the extended position according to the embodiment of the present invention.

[0029] Figure 7 for Figure 6 Partial schematic diagram of point III in the middle.

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

[0031] Fig. 9 It is a schematic diagram of the structure of the state of clearance-free fit between the driving part and the lower end surface of the limiting slide groove when the actuator is in the extended position in an embodiment of the present invention.

[0032] Fig.10 It is a structural schematic diagram of the matching 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] Among them: 1-motor, 2-transmission assembly, 3-end cover assembly, 4-load-bearing assembly, 5-screw, 6-screw nut, 7-retaining frame, 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-driving unit, 17-limiting slide groove. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0035] Example 1

[0036] Actuator, see Figure 1 and Figure 6 ,include:

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

[0038] The transmission mechanism includes a lead screw 5 rotatably arranged in the outer tube and a lead screw nut 6 arranged on the lead screw 5;

[0039] The piston rod 13 is arranged at one end of the opening of the outer tube, and includes a cylindrical sliding portion, which is slidably matched with the outer tube 14;

[0040] The locking linkage mechanism includes a retaining frame 7 connected to the lead screw nut 6 through a thread, an upper bushing 9 abutting against the retaining frame 7 at one end, a lower bushing 11 arranged opposite to the upper bushing 9, an elastic unit 10 arranged between the upper bushing 9 and the lower bushing 11, a plurality of upper locking blocks 8 arranged at the position of the upper bushing 9, a lower locking block 15 arranged at the position of the lower bushing 11, and a spring bushing 12. A limit fit 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, respectively, for limiting the movement of the upper locking block 8 relative to the upper bushing 9 in the direction in which the piston rod extends. and limiting the movement of the lower lock block 15 relative to the lower bushing 11 in the direction of the piston rod retracting, and a clearance space is formed between the upper lock block 8 and the upper bushing 9, and between the lower lock block 15 and the lower bushing 11 at the limiting matching position, which can allow the upper lock block 8 and the lower lock block 15 to move toward the center of the outer cylinder in the radial direction, and the spring bushing 12 is connected to the lower bushing 11 at one end, and connected to the retaining frame 7 at the other end; a driving part 16 is provided on the retaining frame, and a limiting slide groove 17 is provided on the sliding part, and the driving part 16 cooperates to extend into the limiting slide groove, and when the driving part 16 abuts and cooperates with the end surface of the limiting slide groove, it can drive the piston rod 13 to move;

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

[0042] A locking linkage mechanism is adopted to lock the position of the piston rod while enabling the actuator to be locked in the extended position and the retracted position. The elastic unit 10 applies a force to the lead screw nut 6 to rotate the lead screw in the opposite direction, driving the retaining frame 7 to move so that a certain gap is maintained between the retaining frame 7 and the piston rod 13, so that the locking load of the actuator in the locked state is transmitted to the outer cylinder 14 or the load-bearing component 4, and the lead screw 5 only bears the driving load of the extension and retraction actions, thereby providing effective protection for the lead screw 5, improving the reliability of the actuator, and extending the service life of the lead screw and the lead screw nut.

[0043] The elastic unit 10 may be a metal spring.

[0044] In some embodiments, an inwardly extending limiting flange is provided at one end of the outer tube opening, which is used to cooperate with the end surface of the sliding portion to limit 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 cooperates with the lower bushing 11 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 11 and the upper bushing 9 in sequence and is connected to the retaining frame 7.

[0046] In some embodiments, the upper bushing 9 and the lower bushing 11 are cooperatively mounted on the spring bushing.

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

[0048] In some embodiments, it also includes a load-bearing component 4, and the screw 5 is rotatably connected between the load-bearing component 4 and the outer cylinder 14. One end of the load-bearing component abuts against the end cover component 3, and the other end is set in the direction of 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 has an interference fit with the screw head, and is axially positioned and tightened by the end face of the outer cylinder and the end cover assembly.

[0049] In some embodiments, the load-bearing component 4 includes a bearing and a bearing seat. One end of the bearing abuts against the end cover component 3, and the other end is arranged on the bearing seat. One end of the bearing seat is arranged toward the piston rod to limit the piston rod 13.

[0050] In some embodiments, after the lead screw 5 drives the upper bushing 9 and the lower bushing 11 to move through the lead screw nut 6 and 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 cause the lead screw 5 to rotate, thereby separating the driving part 16 from the end face of the limiting slide groove.

[0051] In some embodiments, a motor 1 is also included, which is connected to the lead screw 5 through a transmission assembly 2 and is used to drive the lead screw 5 to rotate. When the lead screw rotates, it can drive the motor to rotate in the reverse direction.

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

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

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

[0055] When the actuator is unlocked and extended in the retracted position, 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 pushes the retainer 7 to move in the extending direction, so that the upper bushing 9 moves axially by A, where A is the distance between the driving part 16 of the retainer and the lower end surface of the limiting slide groove;

[0056] The upper bushing 9 compresses the elastic unit 10;

[0057] When the driving part 16 moves to abut against the lower end surface of the limiting slide groove and applies a force in the extending direction to the piston rod 13, under the action of the piston rod, the upper locking block 8 moves in the radial direction, disengages from the upper locking groove, and is placed in the makeshift space of the upper bushing, and the upper locking block 8 is unlocked; at this time, the distance between the upper locking block 8 and the upper bushing 9 is C.

[0058] The driving part 16 pushes the piston rod 13 to move in the extending 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 extended position.

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

[0060] At this time, when the piston rod 13 is subjected to a tensile load, the end surface of the sliding portion of the piston rod abuts against the limiting flange of the outer tube, 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 a tensile load.

[0061] When the piston rod 13 is subjected to a compressive load, since there is a distance D between the driving part 16 and the lower end surface 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 tube 14, so that the screw 5 and the screw nut 6 are not subjected to a compressive load.

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

[0063] When the actuator is unlocked and retracted in the extended position, refer to Figure 6 , Figure 7 , Figure 8 , Fig. 9and Fig.10 , the screw nut 6 is driven to retreat by the reverse rotation of the screw rod, and the retainer 7 is driven to move in the retracting direction. When the retainer moves, the spring bushing 12 is driven to move so that the lower bushing 11 moves axially by E, where E is the distance between the driving portion 16 of the retainer and the upper end surface of the limiting slide groove;

[0064] The lower bushing 11 compresses the elastic unit 10;

[0065] When the driving part 16 moves to abut against the upper end surface of the limiting slide groove and applies a force in the retracting direction to the piston rod 13, under the action of the piston rod, the lower locking block 15 moves in the radial direction, disengages from the lower locking groove, and is placed in the makeshift space of the lower bushing, and the lower locking block 15 is unlocked; at this time, the distance between the lower locking block 15 and the lower bushing 11 is G.

[0066] The driving part 16 drives the piston rod 13 to move in the retracting 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 locking 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 in the extending direction to the lower bushing 11, and acts on the screw nut 6, driving the screw to rotate in the opposite direction, so that the screw nut 6 moves in the extending direction G, and 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 driving part 16 of the retaining frame 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 a tensile load, the tensile load is transmitted to the end cover assembly 3 through the locking cooperation between the upper locking block 8 and the upper locking groove 141, and because there is a distance H between the driving part 16 and the upper end surface of the limiting slide groove at this time, the tensile load will not be transmitted to the screw nut through the retaining frame 7, so that the screw 5 and the screw nut 6 are not subjected to a 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 transmits the compressive load 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 only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment 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: An outer cylinder, one end of which is provided with an end cap assembly; The transmission mechanism includes a lead screw rotatably arranged in the outer cylinder and a lead screw nut arranged on the lead screw; The piston rod is arranged at one end of the opening of the outer tube, and comprises a sliding portion in a cylindrical shape, wherein the sliding portion is slidably matched with the outer tube; The locking linkage mechanism includes a retaining frame connected to the screw nut, an upper bushing abutting the retaining frame at one end, a lower bushing arranged opposite to the upper bushing, an elastic unit arranged between the upper bushing and the lower bushing, a plurality of upper locking blocks arranged at the position of the upper bushing, a lower locking block and a spring bushing arranged at the position of the lower bushing, wherein a limiting fit is formed between the upper locking block and the upper bushing, and between the lower locking block and the lower bushing, respectively, for limiting the movement of the upper locking block relative to the upper bushing in the direction of extending the piston rod and limiting the movement of the lower lock The block moves relative to the lower bushing in the direction of retraction of the piston rod, 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 matching position, which can allow the upper locking block and the lower locking block to move toward the center of the outer cylinder in the radial direction. The spring bushing is connected to the lower bushing at one end and to the retaining frame at the other end; a driving part is provided on the retaining frame, and a limiting slot is provided on the sliding part. The driving part cooperates and extends into the limiting slot, and can drive the piston rod to move when the driving part abuts and cooperates with the end face of the limiting slot; The outer cylinder is provided with an upper lock groove and a lower lock groove that cooperate with the upper lock block and the lower lock block; the sliding part is provided with a limiting hole that cooperates with the upper lock block and the lower lock block, and the upper lock block and the lower lock block are respectively arranged in the corresponding limiting holes; when the upper lock block and the lower lock block form a limiting fit with the upper bushing and the lower bushing, the upper lock block and the lower lock block can extend into the upper lock groove and the lower lock groove respectively, and when the upper lock block and the lower lock block move into the make way space, the upper lock block and the lower lock block can escape from the upper lock groove and the lower lock groove.

2. The actuator according to claim 1, characterized in that: An inwardly extending limiting flange is arranged at one end of the opening of the outer cylinder, and is used for cooperating with the end surface of the sliding part to limit 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 matches with the lower bushing and forms a limit 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 retaining frame.

4. The actuator according to claim 3, characterized in that: The upper bushing and the lower bushing are cooperatively sleeved on the spring bushing.

5. The actuator according to claim 1 or 4, characterized in that: The upper bushing and the lower bushing are arranged in 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 screw is rotatably connected to the outer cylinder through the load-bearing component, one end of the load-bearing component abuts against the end cover component, and the other end is arranged in the direction of the piston rod, and 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 seat. One end of the bearing abuts against the end cover component, and the other end is arranged on the bearing seat. One end of the bearing seat is arranged in the direction of the piston rod for limiting the piston rod.

8. The actuator according to claim 1 or 6, characterized in that: The lead screw drives the upper bushing and the lower bushing to move through the lead screw nut, and after the upper locking block and the lower locking block move to the locking position, the elastic unit applies a reverse force to the lead screw nut to rotate the lead screw, so that the driving part is separated 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 the lead screw through a transmission assembly and is used to drive the lead screw to rotate. When the lead screw rotates, it can drive the motor to rotate in the reverse direction.

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