A dual-mode electromechanical actuator

Abstract

The present application relates to a kind of bimodal electro-mechanical actuator, including screw rod stator, outer tube, front locking ring, rear locking ring, screw rod, sleeve, piston rod and keep cylinder frame, screw rod, front locking ring and rear locking ring are all installed in outer tube, screw rod passes through front locking ring and rear locking ring, screw rod stator and sleeve are all installed on screw rod, screw rod stator and sleeve are connected, piston rod and keep cylinder frame are connected, the actuator further includes lock control unit and emergency unlocking unit, the keep cylinder frame is installed on sleeve by lock control unit, the emergency unlocking unit is installed on outer tube, the emergency unlocking unit and lock control unit are connected, ordinary locking process or emergency locking process is realized by emergency unlocking unit and lock control unit. Ordinary locking is realized while realizing emergency locking, locking process will use locking unit, ensure that unlocking is simple and fixed firm in locking process;Memory alloy spring does not move with locking unit, avoid alloy memory spring easy to fail.

Description

Technical Field

[0001] This invention relates to the field of electromechanical actuator technology, and in particular to a dual-mode electromechanical actuator. Background Technology

[0002] Electromechanical actuators are linear motion execution mechanisms composed of a motor and a mechanical transmission mechanism (gears and ball / roller screws). They offer advantages such as compact structure and good maintainability. In the aviation field, electromechanical actuators are gradually replacing hydraulic or electro-hydraulic actuators, becoming the actuating elements of landing gear, wings, brakes, and other mechanisms. Aviation actuators generally have a locking mechanism, automatically locking after reaching a set position, allowing them to withstand greater loads. To meet the stringent reliability requirements of the aviation industry, aviation actuators typically have an emergency protection mechanism. In the event of an anomaly (such as motor failure or power failure), the actuator can automatically unlock, move to an emergency working position, and lock, ensuring the safety of the entire aircraft. For example, a landing gear retraction actuator will automatically lower and lock the landing gear in the event of an anomaly.

[0003] Chinese patent application CN118462796A discloses an electromechanical actuator with an emergency locking function, its working method, and its application. The electromechanical actuator includes a retaining cylinder, a backstop ring, a shape memory alloy spring, and a piston rod. The backstop ring is placed inside the retaining cylinder, and the piston rod is fixed to the retaining cylinder with bolts. The backstop ring and the piston rod are connected by a shape memory alloy spring. The shape memory alloy spring in this patent uses its deformation function at different temperatures to drive the backstop ring of the electromechanical actuator, realizing automatic unlocking in the non-emergency position and automatic locking in the emergency position. However, the deformation length of the shape memory alloy spring makes locking or unlocking inconvenient, requiring further reduction of unlocking difficulty and improvement of locking strength. At the same time, the shape memory alloy spring in this patent moves with the retaining cylinder, and the required heating power supply needs to use moving contact, which is prone to failure.

[0004] Therefore, providing an electromechanical actuator that can achieve emergency locking on the basis of ordinary locking, while reducing the difficulty of unlocking, increasing the locking strength, and avoiding the failure of shape memory alloy springs is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a dual-mode electromechanical actuator.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to one aspect of the present invention, a dual-mode electromechanical actuator is provided, comprising a lead screw stator, an outer cylinder, a front locking ring, a rear locking ring, a lead screw, a sleeve, a piston rod, and a retaining sleeve frame. The lead screw, the front locking ring, and the rear locking ring are all installed in the outer cylinder. The lead screw passes through the front locking ring and the rear locking ring. The lead screw stator and the sleeve are both installed on the lead screw and are connected. The piston rod and the retaining sleeve frame are connected. The actuator further includes a locking control unit and an emergency unlocking unit. The retaining sleeve frame is installed on the sleeve via the locking control unit. The emergency unlocking unit is installed on the outer cylinder and is connected to the locking control unit. The emergency unlocking unit and the locking control unit enable a normal locking process or an emergency locking process.

[0008] As a preferred technical solution, the locking unit includes a front thrust ring, a rear thrust ring, a first steel ball, a second steel ball, and a spring. The front thrust ring and the rear thrust ring are connected by the spring. The front thrust ring and the rear thrust ring are mounted on the sleeve. The first steel ball is mounted on the front thrust ring, and the second steel ball is mounted on the rear thrust ring. The retaining sleeve is mounted on the first steel ball and the second steel ball.

[0009] As a preferred technical solution, the diameter of the first steel ball is larger than the diameter of the second steel ball.

[0010] As a preferred technical solution, both the front thrust ring and the rear thrust ring include grooves, the first steel ball matches the groove of the front thrust ring, and the second steel ball matches the groove of the rear thrust ring.

[0011] As a preferred technical solution, the retaining cylinder includes a first circular hole and a second circular hole, wherein the first steel ball is connected to the front locking ring through the first circular hole, or the second steel ball is connected to the rear locking ring through the second circular hole.

[0012] As a preferred technical solution, the actuator includes a stop nut, the sleeve includes a thread, the thread is installed on the edge of the sleeve, the stop nut and the thread are connected, and the stop nut and the sleeve compress the spring.

[0013] As a preferred technical solution, the retaining sleeve includes a boss, which contacts the locking nut.

[0014] As a preferred technical solution, the emergency unlocking unit includes a shape memory alloy spring, an emergency unlocking push rod, an emergency unlocking baffle, and a rear stop block. The rear stop block includes a placement groove and is installed in the outer cylinder. The emergency unlocking baffle is installed on the rear stop block. The emergency unlocking push rod passes through the lead screw stator and the sleeve and is connected to the rear thrust ring. The shape memory alloy spring is installed in the placement groove and is connected to the emergency unlocking push rod through the emergency unlocking baffle.

[0015] As a preferred technical solution, the actuator further includes a guide key, and the outer cylinder is connected to the sleeve and the retaining frame respectively through the guide key.

[0016] As a preferred technical solution, the sleeve, retaining sleeve and outer cylinder are all provided with guide grooves, and the guide key is installed in the guide groove.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. This invention, by setting up an emergency activation unit, simultaneously realizes the emergency locking process during the normal locking process. In addition, both the normal locking process and the emergency locking process use the locking unit. Through the reasonable design of the locking unit structure, it ensures that unlocking is simple and the fixation is reliable during the locking process. The memory alloy spring in the emergency activation unit does not move with the locking unit, avoiding the easy failure of the alloy memory spring.

[0019] 2. In the emergency start-up of the present invention, the emergency unlocking unit first provides a small force to enable the locking unit to automatically unlock at the rear locking ring. Then, under the action of gravity, the first steel ball automatically locks at the front locking ring. Unlocking is convenient and quick, and the locking force at the front locking ring is greater, making the locking more reliable and ensuring emergency locking.

[0020] 3. In this invention, the front thrust ring and the rear thrust ring are compressed by a spring in a compressed state. When unlocking, the rear thrust ring compresses the spring, causing the second steel ball to fall from the rear locking ring into the rear thrust ring. When locking, the front thrust ring presses the first steel ball into the front locking ring under the action of the spring.

[0021] 4. The diameter of the first steel ball in this invention is larger than that of the second steel ball, and the locking forces provided are different. The first steel ball cooperates with the front thrust ring and the front locking ring, while the second steel ball cooperates with the rear thrust ring and the rear locking ring. When unlocking, the diameter of the second steel ball is smaller, making it easier to unlock. When locking, the first steel ball can provide a greater locking force and is not easy to fall off.

[0022] 5. This invention extends the alloy memory spring by heating it, thereby sequentially pushing the emergency unlocking baffle, the emergency unlocking push rod, and the rear thrust ring. Meanwhile, the second steel ball has a small diameter, so the alloy memory spring only needs to undergo a small deformation and a small thrust to complete the unlocking, making unlocking convenient and reliable. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention;

[0024] Figure 2 A schematic diagram of the AA cross-section of the invention;

[0025] Figure 3 A schematic cross-sectional view of the invention (BB).

[0026] Figure 4 A schematic diagram of the CC cross-section of the invention;

[0027] Figure 5 A schematic diagram of the elongation and locking state of the invention;

[0028] Figure 6 A schematic diagram of the contraction and locking state of the invention;

[0029] Figure 7 A schematic diagram of the elongation of a memory alloy spring for an invention;

[0030] Figure 8 A magnified view of the elongation L of the memory alloy spring of the invention;

[0031] Figure 9 A schematic diagram illustrating the mechanism for unlocking the invention;

[0032] Figure 10 A magnified view of the part at point K of the invention.

[0033] 1-Screw stator, 2-Outer cylinder, 3-Front locking ring, 4-Rear locking ring, 5-Sleeve, 6-Front stop, 7-Front fixed ring, 8-Piston rod, 9-Stop nut, 10-Front thrust ring, 11-First steel ball, 12-Rear thrust ring, 13-Retaining sleeve B, 14-Second steel ball, 15-Emergency unlocking push rod, 16-Emergency unlocking baffle, 17-Rear stop, 18-Rear fixed ring, 19-Screw, 20-Spring, 21-Memory alloy spring, 22-Carbon ring, 23-Bearing retaining ring, 24-Bearing nut A, 25-Bearing nut B, 26-Bearing, 27-Guide key, AA. First section, BB. Second section, CC. Third section, L. Enlarged view of memory alloy spring extension, K. Enlarged view of mechanism unlocking. Detailed Implementation

[0034] 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 only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] Based on the landing gear retraction and extension movements, the actuator has two locking states: a retracted and locked state during flight, and an extended and locked state on the ground. Before landing, the actuator should unlock from the retracted position, move to the extended position, and lock. In emergency situations such as motor failure, the actuator may not unlock automatically, requiring emergency unlocking to allow the landing gear to extend under gravity. After the landing gear is released, the actuator should be able to lock remotely, entering the extended locked state to ensure a safe landing. Currently, there is no emergency unlocking design for the electromechanical actuator. Based on whether the actuator can function normally, it is divided into two states: normal start and emergency start, i.e., dual-mode.

[0036] To avoid accidents, the actuator must be in the extended and locked state and securely locked before the aircraft lands. Therefore, this invention needs to enable emergency unlocking while ensuring that the actuator can maintain better locking in the extended and locked state.

[0037] This invention provides a dual-mode electromechanical actuator. By incorporating an emergency start unit, it simultaneously achieves an emergency locking process during the normal locking process. Furthermore, both the normal and emergency locking processes utilize the locking unit. Through a rationally designed structure, the locking unit ensures simple unlocking and reliable fixation during the locking process. The shape memory alloy spring in the emergency start unit does not move with the locking unit, preventing easy failure of the alloy shape memory spring. In the emergency start of this invention, the emergency unlocking unit first provides a small force to automatically unlock the locking unit at the rear locking ring. Subsequently, under the action of gravity, the first steel ball automatically locks at the front locking ring. Unlocking is convenient and quick, while the greater locking force at the front locking ring ensures a more reliable lock and guarantees emergency locking. This invention utilizes a spring in a compressed state to compress the front and rear thrust rings. During unlocking, the rear thrust ring compresses the spring, causing the second steel ball to fall from the rear locking ring into the rear thrust ring. During locking, the front thrust ring, under the action of the spring, presses the first steel ball into the front locking ring. In this invention, the diameter of the first steel ball is larger than that of the second steel ball, providing different locking forces. The first steel ball cooperates with the front thrust ring and the front locking ring, while the second steel ball cooperates with the rear thrust ring and the rear locking ring. When unlocking, the smaller diameter of the second steel ball makes unlocking easier, while when locking, the first steel ball provides a greater locking force, making it less prone to falling off. This invention uses a heated alloy memory spring to lengthen it, thereby sequentially pushing the emergency unlocking stop, the emergency unlocking push rod, and the rear thrust ring. Simultaneously, the smaller diameter of the second steel ball means that the alloy memory spring only requires a small deformation and a small thrust to complete the unlocking process, making unlocking convenient and reliable.

[0038] Example 1

[0039] like Figures 1-4As shown, a dual-mode electromechanical actuator includes a lead screw stator 1, an outer cylinder 2, a front locking ring 3, a rear locking ring 4, a lead screw 19, a sleeve 5, a piston rod 8, and a retaining cylinder frame 13. The lead screw 19, the front locking ring 3, and the rear locking ring 4 are all installed in the outer cylinder 2. The lead screw 19 passes through the front locking ring 3 and the rear locking ring 4. The lead screw stator 1 and the sleeve 5 are both installed on the lead screw 19. The lead screw stator 1 and the sleeve 5 are connected. The piston rod 8 and the retaining cylinder frame 13 are connected. The actuator also includes a locking control unit and an emergency unlocking unit. The retaining cylinder frame 13 is installed on the sleeve 5 through the locking control unit. The emergency unlocking unit is installed on the outer cylinder 2. The emergency unlocking unit and the locking control unit are connected to achieve a normal locking process or an emergency locking process.

[0040] The locking unit includes a front thrust ring 10, a rear thrust ring 12, a first steel ball 11, a second steel ball 14, and a spring 20. The front thrust ring 10 and the rear thrust ring 12 are connected by the spring 20. The front thrust ring 10 and the rear thrust ring 14 are mounted on the sleeve 5. The first steel ball 11 is mounted on the front thrust ring 10, and the second steel ball 14 is mounted on the rear thrust ring 12. The retaining sleeve 13 is mounted on the first steel ball 11 and the second steel ball 14.

[0041] The diameter of the first steel ball 11 is larger than that of the second steel ball 14. The different diameters mean different contact surfaces. The larger the diameter, the easier it is to lock and the more secure the fixation. Since the first steel ball 11 is the key component for locking, its diameter is slightly larger. The second steel ball 14 will affect unlocking, so it is slightly smaller to facilitate unlocking.

[0042] Both the front thrust ring 10 and the rear thrust ring 12 include grooves. The first steel ball 11 matches the groove of the front thrust ring 10, and the second steel ball 14 matches the groove of the rear thrust ring 12.

[0043] The retaining cylinder 13 includes a first circular hole and a second circular hole. The first steel ball 11 is connected to the front locking ring 3 through the first circular hole, or the second steel ball 14 is connected to the rear locking ring 4 through the second circular hole. The steel balls are sequentially squeezed into the corresponding grooves and circular holes to complete the locking. There are multiple first and second circular holes, which respectively form first circular hole rings and second circular hole rings, and are sequentially installed on the retaining cylinder 13.

[0044] The actuator includes a stop nut 9, the sleeve 5 includes threads, the threads are installed on the edge of the sleeve 5, the stop nut 9 is connected to the threads, and the stop nut 9 and the sleeve 5 compress the spring 20.

[0045] The retaining sleeve 13 includes a boss that contacts the locking nut 9.

[0046] The emergency unlocking unit includes a shape memory alloy spring 21, an emergency unlocking push rod 15, an emergency unlocking baffle 16, and a rear stop block 17. The rear stop block 17 includes a placement groove and is installed in the outer cylinder 2. The emergency unlocking baffle 16 is installed on the rear stop block 17. The emergency unlocking push rod 15 passes through the lead screw stator 1 and the sleeve 5 and is connected to the rear thrust ring 12. The shape memory alloy spring 21 is installed in the placement groove and is connected to the emergency unlocking push rod 15 through the emergency unlocking baffle 16.

[0047] The actuator also includes a guide key 27, through which the outer cylinder 2 is connected to the sleeve 5 and the retaining cylinder frame 13 respectively.

[0048] The sleeve 5, the retaining sleeve 13 and the outer sleeve 2 are all provided with guide grooves, and the guide key 27 is installed in the guide groove.

[0049] In this embodiment, the actuator components operate around the lead screw 19. The sleeve 5 is bolted to the lead screw stator 1 and is mounted on the lead screw 19. The front thrust ring 10 and the rear thrust ring 12 are mounted on the outside of the sleeve 5, and the force between the two thrust rings is provided by the spring 20. The retaining sleeve 13 is mounted on the outside of the front thrust ring 10 and the rear thrust ring 12. The left end of the sleeve 5 is threaded and connected to the stop nut 9. The stop nut 9 contacts the inner boss of the retaining sleeve 13 to prevent the retaining sleeve 13 from slipping. The piston rod 8 is fixed to the retaining sleeve 13 with bolts. The outer wall of the retaining sleeve 13 has a first round hole and a second round hole, which can accommodate the first steel ball 11 (16mm) and the second steel ball 14. (10mm) Extends under the compression of the front thrust ring 10 / rear thrust ring 12; the outer wall of the sleeve 5 and the retaining sleeve 13 has a guide groove and is fixed with the guide key 27 by bolts. The guide key 27 is placed in the guide groove on the inner wall of the outer cylinder 2 and fits tightly with the outer cylinder 2; the shape memory alloy spring 21 is fixed in the groove of the rear stop 17 and contacts the emergency unlocking stop 16; the emergency unlocking push rod 15 is fixed with bolts to the emergency unlocking stop 16 and contacts the rear thrust ring 12; the shape memory alloy spring 21 is covered with a resistance wire. When the resistance wire is energized, the temperature rises and the shape memory alloy spring stretches; when the resistance wire is not energized, the temperature drops and the shape memory alloy spring returns to its normal length.

[0050] The actuator also includes a front stop 6, a front fixing ring 7, a rear fixing ring 18, a spring ring 22, a bearing retaining ring 23, a bearing nut A24, a bearing nut B, and a bearing 26. The front stop 6, the front fixing ring 7, the rear fixing ring 18, the spring ring 22, the bearing retaining ring 23, the bearing nut A24, the bearing nut B, and the bearing 26 mount the lead screw 19 in the outer cylinder 2.

[0051] The actuator is mounted on the aircraft landing gear and has two operating states: a retracted locking state and an extended locking state. In the extended locking state, the first steel ball 11 is in the groove of the front locking ring 3, and the piston rod 8 extends out of the outer cylinder 2. In the retracted locking state, the second steel ball 14 is in the groove of the rear locking ring 4, and the piston rod 8 is retracted into the outer cylinder 2.

[0052] like Figure 5 As shown, the normal elongation process:

[0053] When the actuator needs to extend, the lead screw 19 rotates, causing the lead screw stator 1 to move to the left. This, in turn, causes the sleeve 5 to push the rear thrust ring 12, compressing the spring 20 and moving to the left to the unlocked position. At this time, the second steel ball 14 is compressed by the rear locking ring 4 and thus retracts into the retaining sleeve 13, completing the unlocking of the mechanism. Under the action of the lead screw stator 1, the retaining sleeve 13 drives the piston rod 8 to move to the left, extending out of the actuator. When the mechanism moves to the extended locking position, the front thrust ring 10, under the action of the spring 20, pushes the first steel ball 11 out and embeds it into the groove of the front locking ring 3, completing the locking of the mechanism.

[0054] like Figure 6 As shown, the normal contraction process:

[0055] When the actuator needs to retract, the lead screw 19 rotates, causing the lead screw stator 1 and sleeve 5 to move to the right. Since the stop nut 9 is fixed to the thread at the front end of the sleeve and contacts the front thrust ring 10, the lead screw stator 1 will cause the front thrust ring 10 to compress the spring 20 and move to the right to the unlocked position. At this time, the first steel ball 11 is compressed by the front locking ring 3 and thus retracts into the retaining sleeve 13, and the mechanism completes the unlocking. Under the action of the lead screw stator 1, the retaining sleeve 13 drives the piston rod 8 to move to the right and retracts into the actuator. When the mechanism moves to the retracted locking position, the rear thrust ring 12, under the action of the spring 20, pushes out the second steel ball 14 and embeds it into the groove of the rear locking ring 4, and the mechanism completes the locking.

[0056] like Figures 7-10 As shown, the emergency locking process:

[0057] In the event of an emergency, the heating wire attached to the shape memory alloy spring 21 is activated, causing the shape memory alloy spring 21 to extend and push the emergency unlocking baffle 16 and the emergency unlocking push rod 15, thereby pushing the rear thrust ring 12 to the unlocking position. At this time, under the action of gravity, the piston rod 8 automatically slides to the left, driving the retaining cylinder 13 to move. At this time, the second steel ball 14 is squeezed back into the retaining cylinder 13 by the rear locking ring 4, and the mechanism completes the unlocking. After the actuator piston rod 8 automatically slides to the extended locking position under the action of gravity, the front thrust ring 10, under the action of the spring 20, squeezes out the first steel ball 11 and inserts it into the groove of the front locking ring 3, and the mechanism completes the extended locking.

[0058] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dual-mode electromechanical actuator, comprising a lead screw stator (1), an outer cylinder (2), a front locking ring (3), a rear locking ring (4), a lead screw (19), a sleeve (5), a piston rod (8), and a retaining sleeve (13), wherein the lead screw (19), the front locking ring (3), and the rear locking ring (4) are all installed in the outer cylinder (2), the lead screw (19) passes through the front locking ring (3) and the rear locking ring (4), the lead screw stator (1) and the sleeve (5) are both installed on the lead screw (19), the lead screw stator (1) and the sleeve (5) are connected, and the piston rod (8) and the retaining sleeve (13) are connected, characterized in that, The actuator also includes a locking control unit and an emergency unlocking unit. The retaining sleeve (13) is mounted on the sleeve (5) through the locking control unit, and the emergency unlocking unit is mounted on the outer sleeve (2). The emergency unlocking unit and the locking control unit are connected, and the normal locking process or the emergency locking process is realized through the emergency unlocking unit and the locking control unit. The locking unit includes a front thrust ring (10), a rear thrust ring (12), a first steel ball (11), a second steel ball (14), and a spring (20). The front thrust ring (10) and the rear thrust ring (12) are connected by the spring (20). The front thrust ring (10) and the rear thrust ring (12) are mounted on the sleeve (5). The first steel ball (11) is mounted on the front thrust ring (10), and the second steel ball (14) is mounted on the rear thrust ring (12). The retaining sleeve (13) is mounted on the first steel ball (11) and the second steel ball (14). The emergency unlocking unit includes a shape memory alloy spring (21), an emergency unlocking push rod (15), an emergency unlocking baffle (16), and a rear stop (17). The rear stop (17) includes a placement groove and is installed in the outer cylinder (2). The emergency unlocking baffle (16) is installed on the rear stop (17). The emergency unlocking push rod (15) passes through the lead screw stator (1) and the sleeve (5) and is connected to the rear thrust ring (12). The shape memory alloy spring (21) is installed in the placement groove and is connected to the emergency unlocking push rod (15) through the emergency unlocking baffle (16).

2. The dual-mode electromechanical actuator according to claim 1, characterized in that, The diameter of the first steel ball (11) is larger than the diameter of the second steel ball (14).

3. The dual-mode electromechanical actuator according to claim 1, characterized in that, Both the front thrust ring (10) and the rear thrust ring (12) include grooves. The grooves of the first steel ball (11) and the front thrust ring (10) are matched, and the grooves of the second steel ball (14) and the rear thrust ring (12) are matched.

4. A dual-mode electromechanical actuator according to claim 1, characterized in that, The retaining cylinder (13) includes a first circular hole and a second circular hole. The first steel ball (11) is connected to the front locking ring (3) through the first circular hole, or the second steel ball (14) is connected to the rear locking ring (4) through the second circular hole.

5. A dual-mode electromechanical actuator according to claim 1, characterized in that, The actuator includes a stop nut (9), the sleeve (5) includes a thread, the thread is installed on the edge of the sleeve (5), the stop nut (9) and the thread are connected, and the stop nut (9) and the sleeve (5) compress the spring (20).

6. A dual-mode electromechanical actuator according to claim 5, characterized in that, The retaining sleeve (13) includes a boss that contacts the locking nut (9).

7. A dual-mode electromechanical actuator according to claim 1, characterized in that, The actuator also includes a guide key (27), through which the outer cylinder (2) is connected to the sleeve (5) and the retaining cylinder frame (13) respectively.

8. A dual-mode electromechanical actuator according to claim 7, characterized in that, The sleeve (5), retaining sleeve (13) and outer sleeve (2) are all provided with guide grooves, and the guide key (27) is installed in the guide groove.

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