Split nut locking and releasing device with mistaken unlocking prevention

Abstract

This application discloses a split nut locking and releasing device with anti-misoperation locking limit, comprising: a housing assembly, a split nut, an outer sleeve, a lower limiting cylinder, a limiting block, a limiting ball, a separating cone, and a shape memory alloy wire. A first elastic reset element is provided at the bottom of the limiting block; a second elastic reset element is provided between the outer sleeve and the lower limiting cylinder; the split nut is disposed inside the outer sleeve, with its top end abutting against the top of the housing assembly, and its bottom end engaging with the separating cone; a third elastic reset element is provided at the bottom of the separating cone; the shape memory alloy wire passes through a U-shaped channel on the limiting block, and both ends of the shape memory alloy wire pass upwards through pre-set channels on the outer sleeve and the separating cone, respectively, before being guided and fixed to the housing assembly. This invention can effectively suppress unintended unlocking caused by external impacts or disturbances; simultaneously, the device structure is easy to disassemble and maintain, has automatic reset capability, and can be reused multiple times.

Description

Technical Field

[0001] This application relates to the field of locking and releasing devices, and in particular to a split nut locking and releasing device with anti-misunderstanding locking limit. Background Technology

[0002] In typical space missions such as high-precision satellite exploration and precision space experiments, satellites often need to carry precision instruments or large-mass integrated platform payloads. For these space exploration missions, the locking-release device is a key component to ensure the safe and stable operation of the spacecraft and payloads (such as optical integrated platforms) in the strong vibration environment of the launch phase and the vacuum and microgravity environment of the on-orbit phase. Its performance directly affects the maintenance of payload status, structural safety, and mission execution accuracy, thus having a decisive impact on the mission success rate. Therefore, relevant satellite components must usually undergo a complete "lock-release" process: achieving absolutely reliable locking constraints during the launch phase and completing ultra-low disturbance release after the satellite accurately enters orbit to ensure the normal operation of the payload in orbit and meet the requirements of high-precision measurement.

[0003] Currently, locking and releasing devices for vacuum environments can be broadly categorized into two types based on their working principles: pyrotechnic and non-pyrotechnic. Each type has its advantages and limitations. Pyrotechnic devices (such as explosive bolts and pyrotechnic cutters) are the most widely used solution in traditional space missions. They rely on pyrotechnics for rapid release and offer advantages such as compact structure, high locking force, and low cost. However, these devices generate significant instantaneous impacts and strong vibrations during operation, easily causing attitude deviations or even structural damage to precision loads, leading to irreversible effects on sensitive components such as sensors and circuits. Furthermore, pyrotechnic releases are often accompanied by smoke and particulate contamination, which can easily adhere to the surface of the load or the optical lenses of spacecraft in a vacuum environment, resulting in decreased imaging quality and deteriorated detection accuracy. To reduce the impact and contamination risks associated with pyrotechnic devices, non-pyrotechnic locking and releasing devices are gradually becoming an important development direction. Non-pyrotechnic devices can be further subdivided into three locking methods: mechanical, shape memory alloy, and electromagnetic. Mechanical locking and releasing devices offer strong adaptability and high control precision, but typically suffer from limitations such as relatively limited locking force, complex structure, and significant system weight. Electromagnetic locking mechanisms offer greater locking force and wider applicability, but their reliance on electromagnetic coils for driving force generates strong magnetic field interference during operation, affecting sensitive loads such as magnetic field measurements. Furthermore, electromagnetic components often require continuous power supply, resulting in high on-orbit power consumption. In contrast, shape memory alloy devices offer advantages such as high locking force, compact structure, no pollution, and low impact, without introducing electromagnetic interference. However, they may generate localized thermal disturbances during heating and have limited position control precision, making them unsuitable for locking high-precision structures extremely sensitive to minute internal deformations. Nevertheless, for locking constraints on external integrated platforms or large-mass loads, these devices demonstrate good compatibility and application potential under low-impact release requirements.

[0004] Shape memory alloy (SME) locking mechanisms, as a novel non-pyrotechnic locking and releasing scheme, are currently widely used in research to drive segmented nuts with SME alloys for locking and releasing. However, there are various technical approaches to the driving method: one approach directly uses the SME alloy as a power source for unlocking; another approach uses mechanisms such as torsion springs or flywheels to store energy and achieve a limit, then the SME alloy releases the limit to release the stored energy, thus completing the unlocking. Each method has its advantages and disadvantages. For example, the former has a relatively simple structure but relatively low reliability against disturbances in complex external environments; the latter has higher reliability but a more complex overall structure and greater integration difficulty. Therefore, this invention proposes a segmented nut locking and releasing device with a limit that prevents mis-locking. Summary of the Invention

[0005] This application provides a split nut locking and releasing device with anti-misunderstanding locking limit, which can effectively suppress unexpected unlocking caused by external impact or disturbance; at the same time, the device structure is easy to disassemble and maintain, has automatic reset capability, and can be reused multiple times.

[0006] In view of this, this application provides a split nut locking and releasing device with anti-misunderstanding locking limit, including: a housing assembly, a split nut, an outer sleeve, a lower limiting cylinder, a limiting block, a limiting ball, a separating cone, and a shape memory alloy wire;

[0007] The lower limiting cylinder is fixedly disposed at the bottom of the housing assembly;

[0008] The lower limiting cylinder has uniformly distributed receiving holes on its side wall for accommodating the limiting ball;

[0009] The limiting block is axially movable inside the lower limiting cylinder, and the bottom of the limiting block is connected to the bottom of the housing assembly through a first elastic reset member.

[0010] The outer side wall of the limiting block is provided with an annular groove for cooperating with the limiting ball;

[0011] The outer sleeve is located inside the housing assembly, and the outer sleeve is slidably fitted onto the lower limiting sleeve along the axial direction;

[0012] The inner wall of the outer sleeve is provided with a limiting groove for cooperating with the limiting ball;

[0013] A second elastic reset element is provided between the outer sleeve and the lower limiting sleeve;

[0014] The segmented nut is disposed inside the outer sleeve, and the top end of the segmented nut abuts against the inclined surface of the top of the housing assembly.

[0015] The bottom end of the split nut is provided with a positioning structure;

[0016] The separating cone is disposed inside the outer sleeve and is connected to the outer sleeve through a third elastic reset member;

[0017] The separating cone is located below the split nut, and the separating cone is provided with a limiting protrusion that cooperates with the positioning structure to prevent the split nut from rotating.

[0018] The outer sleeve is provided with a roller for radially limiting the split nut and axially rolling guide it;

[0019] The limiting block is provided with a U-shaped channel;

[0020] The shape memory alloy wire is threaded through the U-shaped channel, and the two ends of the shape memory alloy wire pass upward through the channels preset on the outer sleeve and the separation cone, respectively, and are then turned and fixed to the housing assembly by the guide.

[0021] In the locked state, the limiting block presses against the limiting ball, keeping the limiting ball within the limiting groove and the receiving hole, preventing the outer sleeve from moving axially; the top end of the split nut abuts against the inclined surface at the top of the housing assembly, and the bottom end engages with the limiting protrusion of the separating cone, forming an axial constraint; the roller radially constrains the split nut.

[0022] When the shape memory alloy wire contracts, it first drives the limiting block to move upward, so that the limiting ball enters the annular groove and releases the limiting of the outer sleeve; then it drives the outer sleeve to move downward, compressing the second elastic reset member, and the roller releases the radial constraint on the split nut. The split nut expands radially with the assistance of the third elastic reset member and the separating cone.

[0023] After power failure, the second elastic reset member drives the outer sleeve to reset, and the first elastic reset member drives the limiting block to reset, so that the limiting ball is pressed back into the limiting groove and the receiving hole.

[0024] Optionally, the housing assembly includes a housing and a bottom cover removably mounted to the bottom of the housing;

[0025] The lower limiting cylinder is fixedly installed on the top of the bottom end cover;

[0026] The bottom end cap is also provided with an inner sleeve;

[0027] The inner sleeve is located inside the lower limiting sleeve and is used to limit the bottom of the limiting block;

[0028] The first elastic reset member is disposed inside the inner sleeve.

[0029] Optionally, the outer sleeve includes an integrally formed upper sleeve and a lower sleeve;

[0030] The lower sleeve has the limiting groove on its inner wall;

[0031] The inner wall of the upper sleeve is provided with a mounting groove for accommodating the roller;

[0032] Both the split nut and the separating cone are disposed inside the upper sleeve;

[0033] The upper sleeve has the channel at its bottom;

[0034] The channel includes a vertical channel for connecting the upper sleeve and the lower sleeve, and a parallel channel for connecting the upper sleeve and the inner cavity of the housing assembly.

[0035] The vertical channel is connected to the parallel channel.

[0036] Optionally, a separation cone channel is provided at the bottom of the separation cone;

[0037] The separating cone channel is connected to the vertical channel and the parallel channel;

[0038] The two ends of the shape memory alloy wire pass upward through the vertical channel, the separation cone channel and the parallel channel respectively, and then are turned by the guide to pass out of the housing assembly, and finally fixed on the connecting post on the top outer side of the housing assembly.

[0039] Optionally, the positioning structure at the bottom of the split nut is a semi-cylindrical groove;

[0040] The limiting protrusion on the separating cone is a semi-cylindrical protrusion that matches the shape of the semi-cylindrical groove.

[0041] Optionally, the guide member is an insulated pulley;

[0042] The insulating pulley is fixedly mounted on the lower limiting cylinder or the bottom end cover.

[0043] Optionally, the number of shape memory alloy wires is two or more;

[0044] Two or more of the shape memory alloy wires are arranged symmetrically.

[0045] The number of the U-shaped channels, the channels, and the guides are matched with the number of the shape memory alloy wires, and are set in a one-to-one correspondence.

[0046] Optionally, an axial guide structure is provided between the lower limiting cylinder and the outer sleeve to prevent the outer sleeve from rotating relative to each other;

[0047] The axial guide structure includes an axial boss disposed on the outside of the lower limiting cylinder and an axial groove disposed on the inside of the outer sleeve.

[0048] The axial boss slides into the axial groove.

[0049] Optionally, the contact surface between the outer shell and the outer sleeve is provided with a lubricating layer, and / or the inner wall of the channel through which the shape memory alloy wire passes is provided with an insulating layer.

[0050] Optionally, the first elastic reset element is a tension spring, the second elastic reset element is a compression spring, and the third elastic reset element is a compression spring.

[0051] As can be seen from the above technical solutions, the embodiments of this application have the following advantages: This split nut locking and releasing device with anti-misoperation locking limit uses a purely mechanical anti-misoperation limiting structure composed of a limiting block, annular groove, limiting ball, limiting groove and receiving hole to reliably lock the outer sleeve in the locked state. It can effectively suppress unexpected unlocking caused by strong vibration of the launching section or external impact without power supply, which significantly improves the safety and reliability of the device; at the same time, the use of a roller instead of a traditional sliding friction component allows for rolling transmission of force and displacement when the outer sleeve moves axially, which greatly reduces the frictional resistance during the unlocking process and reduces the need for the shape memory alloy wire driving force. The design improves the smoothness and stability of unlocking. The sequential action logic of the shape memory alloy wire, when energized and contracting, first drives the limiting block to release the limiting ball, and then drives the outer sleeve to move downwards, ensures a smooth and orderly unlocking process and avoids jamming. After power failure, the first and second elastic reset components automatically drive the limiting block and outer sleeve to reset, making the device fully reusable without manual intervention. The overall structure is compact, and the independent components facilitate disassembly and maintenance. Furthermore, the shape memory alloy wire driving method has advantages such as no pyrotechnic pollution, no electromagnetic interference, and minimal unlocking impact, making it particularly suitable for high-precision aerospace payload locking and releasing missions sensitive to impact and pollution. Attached Figure Description

[0052] Figure 1 This is a cross-sectional view of the split nut locking and releasing device with anti-misunderstanding lock limit in the embodiment of this application;

[0053] Figure 2 This is a front view of the split nut locking and releasing device with anti-misunderstanding lock limit in the embodiment of this application;

[0054] Figure 3 This is a top view of the split nut locking and releasing device with anti-misunderstanding lock limit in the embodiment of this application;

[0055] Figure 4 This is a bottom view of the split nut in the embodiment of this application;

[0056] Figure 5 This is a cross-sectional view of the split nut in the embodiment of this application;

[0057] Figure 6 This is a cross-sectional view of the outer sleeve in an embodiment of this application;

[0058] Figure 7 This is a top view of the outer sleeve in an embodiment of this application;

[0059] Figure 8This is a top view of the separating cone in an embodiment of this application;

[0060] Figure 9 This is a cross-sectional view of the separation cone in an embodiment of this application;

[0061] Figure 10 This is a top view of the lower limiting cylinder in an embodiment of this application;

[0062] Figure 11 This is a cross-sectional view of the lower limiting cylinder in an embodiment of this application;

[0063] Figure 12 This is a schematic diagram of the structure of the limiting block in an embodiment of this application;

[0064] Figure 13 This is a top view of the limiting block in an embodiment of this application;

[0065] Figure 14 This is a cross-sectional view of the limiting block in an embodiment of this application;

[0066] Figure 15 This is a top view of the bottom cover in an embodiment of this application;

[0067] Figure 16 This is a cross-sectional view of the bottom cover in an embodiment of this application.

[0068] The attached figures are labeled as follows:

[0069] 100 - Outer shell, 101 - Connecting post, 200 - Split nut, 201 - Positioning structure, 202 - Internal thread, 203 - Separation groove, 310 - Outer sleeve, 311 - Upper sleeve, 312 - Mounting groove, 313 - Parallel channel, 314 - Vertical channel, 315 - Lower sleeve, 316 - Limiting groove, 317 - Axial groove, 320 - Shape memory alloy wire, 321 - Plastic bushing, 330 - Second elastic reset element, 400 - Roller. 510-Separation cone, 511-Limiting protrusion, 512-Separation cone channel, 520-Third elastic reset component, 610-Insulating pulley, 611-Pulley frame, 620-Lower limiting cylinder, 621-Base plate, 622-Axial boss, 623-Sleeve body, 624-Receiving hole, 710-Limiting block, 711-Annular groove, 712-U-shaped channel, 720-First elastic reset component, 730-Limiting ball, 800-Bottom end cap, 801-Inner sleeve. Detailed Implementation

[0070] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0071] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0072] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0073] This application provides an embodiment of a split nut locking and releasing device with anti-misunderstanding locking limit; please refer to the following for details. Figures 1 to 16 .

[0074] The split nut locking and release device with anti-misinterpretation locking limit in this embodiment includes: a housing assembly, a split nut 200, an outer sleeve 310, a lower limiting cylinder 620, a limiting block 710, a limiting ball 730, a separating cone 510, and a shape memory alloy wire 320.

[0075] It should be noted that the housing assembly is used to provide a mounting base and protection for the internal components. Its specific structure can be designed according to actual assembly requirements. For example, it may include the outer shell 100 and the bottom cover 800, but is not limited to this.

[0076] The lower limiting cylinder 620 is fixedly installed at the bottom of the housing assembly. The side wall of the lower limiting cylinder 620 is evenly provided with receiving holes 624 for accommodating the limiting balls 730. It can be understood that there are multiple limiting balls 730, evenly distributed circumferentially. The number of receiving holes 624 is equal to the number of limiting balls 730, and they are arranged in a one-to-one correspondence to ensure balanced force distribution.

[0077] The limiting block 710 is axially movable inside the lower limiting cylinder 620, and the bottom of the limiting block 710 is connected to the bottom of the housing assembly through the first elastic reset member 720; an annular groove 711 for cooperating with the limiting ball 730 is provided on the outer side wall of the limiting block 710.

[0078] The outer sleeve 310 is located inside the housing assembly and is slidably fitted onto the lower limiting cylinder 620 along the axial direction. The inner wall of the outer sleeve 310 is provided with a limiting groove 316 for cooperating with the limiting ball 730. A second elastic reset member 330 is provided between the outer sleeve 310 and the lower limiting cylinder 620.

[0079] The split nut 200 is disposed inside the outer sleeve 310, and the top end of the split nut 200 abuts against the inclined surface of the top of the housing assembly. The bottom end of the split nut 200 is provided with a positioning structure 201. The separation cone 510 is disposed inside the outer sleeve 310 and is connected to the outer sleeve 310 through a third elastic reset member 520. The separation cone 510 is located below the split nut 200, and the separation cone 510 is provided with a limiting protrusion 511 that cooperates with the positioning structure 201 to prevent the split nut 200 from rotating.

[0080] A roller 400 is provided inside the outer sleeve 310. The roller 400 is used to radially limit the split nut 200 and to roll guide it when the outer sleeve 310 moves axially. A U-shaped channel 712 is provided on the limiting block 710. The shape memory alloy wire 320 passes through the U-shaped channel 712. After the two ends of the shape memory alloy wire 320 pass upward through the preset channels on the outer sleeve 310 and the separating cone 510, they are turned by the guide and fixed to the housing assembly.

[0081] In the locked state, the limiting block 710 presses against the limiting ball 730, keeping the limiting ball 730 within the limiting groove 316 and the receiving hole 624, thereby preventing the outer sleeve 310 from moving axially; at the same time, the top end of the split nut 200 abuts against the inclined surface at the top of the housing assembly, and the bottom end engages with the limiting protrusion 511 of the separating cone 510, forming an axial constraint; the roller 400 radially constrains the split nut 200; at this time, the bolt can be screwed into the split nut 200 to achieve a locking connection.

[0082] When unlocking is required, the shape memory alloy wire 320 is energized, causing it to undergo a martensitic-austenitic phase transformation and contract. The wire first drives the limiting block 710 upwards, causing the limiting ball 730 to enter the annular groove 711, thereby releasing the constraint on the outer sleeve 310. Then, the wire continues to contract, driving the outer sleeve 310 downwards and compressing the second elastic reset member 330. During the downward movement of the outer sleeve 310, the roller 400 rolls relative to the outer sleeve, releasing the radial constraint on the split nut 200. At this point, the split nut 200 expands radially with the assistance of the third elastic reset member 520 and the separating cone 510, releasing the bolt and completing the unlocking process.

[0083] After power failure, the shape memory alloy wire 320 cools and elongates, the second elastic reset member 330 drives the outer sleeve 310 to reset, and the first elastic reset member 720 drives the limiting block 710 to reset, so that the limiting ball 730 is pressed back into the limiting groove 316 and the receiving hole 624. The device returns to the locking ready state and can be reused.

[0084] It should be noted that this split nut locking and releasing device with anti-misoperation locking limit uses a purely mechanical anti-misoperation limiting structure composed of a limiting block 710, annular groove 711, limiting ball 730, limiting groove 316, and receiving hole 624. In the locked state, it reliably axially locks the outer sleeve 310, effectively suppressing unintended unlocking caused by strong vibrations in the launching section or external impacts without the need for power, significantly improving the safety and reliability of the device. Simultaneously, the use of a roller 400 instead of traditional sliding friction components allows for rolling force and displacement transmission during the axial movement of the outer sleeve 310, greatly reducing frictional resistance during unlocking, decreasing the demand for driving force on the shape memory alloy wire 320, and improving the smoothness of unlocking. Smoothness and stability; when the shape memory alloy wire 320 is energized and retracts, it first drives the limiting block 710 to release the limiting ball 730, and then drives the outer sleeve 310 to move downward, ensuring a smooth and orderly unlocking process and avoiding jamming; after power failure, the first elastic reset component 720 and the second elastic reset component 330 automatically drive the limiting block 710 and the outer sleeve 310 to reset, making the device fully reusable without manual intervention; the overall structure is compact, the components are independent and easy to disassemble and maintain, and the shape memory alloy wire 320 driving method has the advantages of no pyrotechnic pollution, no electromagnetic interference, and small unlocking impact, making it particularly suitable for high-precision aerospace payload locking and releasing missions that are sensitive to impact and pollution.

[0085] The above is Embodiment 1 of a split nut locking and releasing device with anti-misunderstanding locking limit provided in this application. The following is Embodiment 2 of a split nut locking and releasing device with anti-misunderstanding locking limit provided in this application. Please refer to the following for details. Figures 1 to 16 .

[0086] The split nut locking and releasing device with anti-misalignment locking limit in this embodiment includes: a housing assembly, a split nut 200, an outer sleeve 310, a lower limiting cylinder 620, a limiting block 710, a limiting ball 730, a separating cone 510, and a shape memory alloy wire 320. The lower limiting cylinder 620 is fixedly disposed at the bottom of the housing assembly, and receiving holes 624 for accommodating the limiting ball 730 are evenly opened on the side wall of the lower limiting cylinder 620. The limiting block 710 is axially movable inside the lower limiting cylinder 620, and the bottom of the limiting block 710 is connected by a first elastic reset member 7. 20 is connected to the bottom of the housing assembly; the outer side wall of the limiting block 710 is provided with an annular groove 711 for cooperating with the limiting ball 730; the outer sleeve 310 is located inside the housing assembly and is axially slidably sleeved on the lower limiting cylinder 620; the inner wall of the outer sleeve 310 is provided with a limiting groove 316 for cooperating with the limiting ball 730; a second elastic reset member 330 is provided between the outer sleeve 310 and the lower limiting cylinder 620; in the locked state, the second elastic reset member 330 is compressed to achieve stable maintenance of the locked state; in the unlocked state... Further compression and energy storage are used to achieve reset and recovery of the shape memory alloy wire 320 after power failure; the split nut 200 is set inside the outer sleeve 310, and the top of the split nut 200 abuts against the inclined surface of the top of the housing assembly. The bottom end of the split nut 200 is provided with a positioning structure 201. The separation cone 510 is set inside the outer sleeve 310 and is connected to the outer sleeve 310 through the third elastic reset member 520, so that the separation cone 510 has the necessary reset and auxiliary pushing capabilities in different working states; the separation cone 510 is located in the split nut 20 Below 0, the separating cone 510 is provided with a limiting protrusion 511 that cooperates with the positioning structure 201 to prevent the split nut 200 from rotating; the outer sleeve 310 is provided with a roller 400 for radially limiting the split nut 200 and axially rolling guide; the limiting block 710 is provided with a U-shaped channel 712; the shape memory alloy wire 320 is inserted into the U-shaped channel 712, and the two ends of the shape memory alloy wire 320 pass upward through the preset channels on the outer sleeve 310 and the separating cone 510 respectively, and are then turned by the guide and fixed to the housing assembly.

[0087] Understandably, in the lower limiting structure, the limiting ball 730 mainly relies on the left and right movement of the limiting ball 730 between the annular groove 711 of the limiting block 710 and the limiting groove 316 of the outer sleeve 310 to achieve the function of mutually limiting the limiting block 710 and the outer sleeve 310.

[0088] In the locked state, the limiting ball 730 is located in the limiting groove 316 of the outer sleeve 310 and the receiving hole 624 of the lower limiting cylinder 620. The limiting block 710 presses against the limiting ball 730 (at this time, the limiting block 710 is pulled and constrained by the first elastic reset member 720), so that the limiting ball 730 is kept in the limiting groove 316 and the receiving hole 624, preventing the outer sleeve 310 from moving axially. At this time, under the double constraint of the pressing constraint of the second elastic reset member 330 and the limiting constraint of the limiting ball 730, the false locking caused by external impact or disturbance can be effectively suppressed. The top end of the split nut 200 abuts against the inclined surface of the top of the housing assembly, and the bottom end cooperates with the limiting protrusion 511 of the separation cone 510 to form an axial constraint. The roller 400 radially constrains the split nut 200, thereby achieving stable locking.

[0089] When the shape memory alloy wire 320 is energized and retracted, it first drives the limiting block 710 to move upward, so that the limiting ball 730 enters the annular groove 711 and releases the limiting of the outer sleeve 310; then it drives the outer sleeve 310 to move downward, compressing the second elastic reset member 330, and the roller 400 releases the radial constraint on the split nut 200. The split nut 200 expands radially with the assistance of the third elastic reset member 520 and the separation cone 510.

[0090] After power failure, the second elastic reset member 330 drives the outer sleeve 310 to reset, and the first elastic reset member 720 drives the limiting block 710 to reset, so that the limiting ball 730 is pressed back into the limiting groove 316 and the receiving hole 624.

[0091] In this embodiment, the housing assembly includes an outer shell 100 and a bottom cover 800 detachably mounted on the bottom of the outer shell 100; a lower limiting cylinder 620 is fixedly disposed on the top of the bottom cover 800. It is understood that by providing a detachable bottom cover 800, the disassembly and maintenance of the internal components are facilitated.

[0092] The bottom cover 800 is also provided with an inner sleeve 801, which is located inside the lower limiting cylinder 620 and is used to limit the bottom of the limiting block 710; the first elastic reset member 720 is disposed inside the inner sleeve 801. It should be noted that the inner sleeve 801 and the lower limiting cylinder 620 are coaxially nested (the outer diameter of the inner sleeve 801 matches the inner diameter of the lower limiting cylinder 620), and the outer diameter of the limiting block 710 matches the inner diameter of the lower limiting cylinder 620, thereby ensuring that the limiting block 710 slides smoothly along the axial direction without deviation.

[0093] The outer sleeve 310 includes an integrally formed upper sleeve 311 and a lower sleeve 315. The inner wall of the lower sleeve 315 is provided with a limiting groove 316, and the inner wall of the upper sleeve 311 is provided with a mounting groove 312 for accommodating the roller 400. The split nut 200 and the separation cone 510 are both disposed inside the upper sleeve 311. It is understood that the integral molding of the upper sleeve 311 and the lower sleeve 315 is beneficial to improving structural strength and assembly accuracy.

[0094] The bottom of the upper sleeve 311 has a channel, which includes a vertical channel 314 for connecting the upper sleeve 311 and the lower sleeve 315, and a parallel channel 313 for connecting the upper sleeve 311 and the inner cavity of the housing assembly. The vertical channel 314 and the parallel channel 313 are connected. It should be noted that the vertical channel 314 extends axially, and the parallel channel 313 is L-shaped and opened on the side wall of the upper sleeve 311. The two are connected to each other and together form the threading path of the shape memory alloy wire 320.

[0095] The bottom of the separation cone 510 has a separation cone channel 512, which connects to the vertical channel 314 and the parallel channel 313. The two ends of the shape memory alloy wire 320 pass upwards through the vertical channel 314, the separation cone channel 512, and the parallel channel 313 respectively, then are guided upwards through the housing assembly and finally fixed to the connecting post 101 on the outer side of the top of the housing assembly. A power supply is connected here to drive the unlocking mechanism. It can be understood that through this channel design, the shape memory alloy wire 320 can first drive the limiting block 710 to move when it retracts. After the limiting block 710 is in position, it then drives the outer sleeve 310 to move by stopping, thus achieving sequential unlocking.

[0096] The positioning structure 201 at the bottom of the split nut 200 is a semi-cylindrical groove, and the limiting protrusion 511 on the separating cone 510 is a semi-cylindrical protrusion that matches the shape of the semi-cylindrical groove. It should be noted that the cooperation between the semi-cylindrical groove and the semi-cylindrical protrusion can effectively prevent the split nut 200 from rotating unexpectedly due to external impact and vibration, thus avoiding the problem of being unable to unlock due to rotation.

[0097] The guide component is an insulated pulley 610, which is fixedly mounted on the lower limiting cylinder 620 or the bottom end cover 800. Two parallel wire grooves are formed on the insulated pulley 610. In this embodiment, the lower limiting cylinder 620 includes a sleeve body 623 and a base plate 621 extending outwards from the bottom of the sleeve body 623 (the overall cross-section of the lower limiting cylinder 620 is U-shaped). Pulley frames 611 are symmetrically arranged on both sides of the top of the base plate 621, and the insulated pulley 610 is mounted on the pulley frames 611. The two ends of the shape memory alloy wire 320 pass upwards through the corresponding vertical channel 314, the separation cone channel 512, and the parallel channel 313, respectively, and then turn upwards through the two wire grooves on the same insulated pulley 610, exiting the housing assembly and finally being fixed to the same connecting post 101 on the outer side of the top of the housing assembly.

[0098] Understandably, the use of insulated pulleys 610 can prevent the shape memory alloy wire 320 from directly contacting the metal parts and causing a short circuit. At the same time, the pulley structure can reduce friction and make the shape memory alloy wire 320 move more smoothly.

[0099] The shape memory alloy wires 320 are two or more, and the two or more shape memory alloy wires 320 are arranged symmetrically. The number of U-shaped channels 712, channels and guides matches the number of shape memory alloy wires 320, and they are set in a one-to-one correspondence. Using multiple symmetrically arranged shape memory alloy wires 320 can achieve more uniform and stable force transmission.

[0100] It should be noted that the main purpose of introducing the insulating pulley 610, U-shaped channel 712, and connecting post 101 on the outer wall of the outer casing 100 in this device is to extend the effective working length of the shape memory alloy wire 320. Since the strain (shrinkage rate) generated by the single energization and contraction of the shape memory alloy wire 320 is relatively limited—approximately 5% for ordinary industrial products and up to 8% for some special products—the total displacement of the pulling limit block 710 and outer sleeve 310 required for unlocking this device is approximately 10mm. Based on a 6% strain rate and considering redundant design, the required original length of the shape memory alloy wire 320 is approximately 20cm. To accommodate such a long shape memory alloy wire 320 within a compact device space, this design employs a winding routing method. The two ends of the shape memory alloy wire 320, threaded within the U-shaped channel 712, pass through corresponding vertical channels 314, separation cone channels 512, and parallel channels 313, respectively. After being turned by the same insulated pulley 610, it is finally fixedly connected to the same connecting post 101. This significantly extends the effective stroke of the wire within a limited volume, meeting the driving displacement requirements. Simultaneously, the shape memory alloy wires 320 are arranged symmetrically in two or more pairs. Even if one wire fails, the remaining wires can still unlock independently, achieving a redundant design. Taking a wire with a diameter of 1mm or 1.2mm as an example, four wires connected in parallel can provide sufficient driving force.

[0101] Furthermore, the shape memory alloy wire 320 in this device has a dual function: First, when the shape memory alloy wire 320 is energized and contracts, it first pulls the limiting block 710 upward, causing the limiting ball 730 to enter the annular groove 711, releasing the pressure of the limiting block 710 on the limiting ball 730, thereby releasing the axial limit of the outer sleeve 310 (this limiting structure is precisely to effectively prevent unexpected malfunctions caused by strong vibrations of the launch section or external impacts); Second, after the limiting block 710 moves into place, the shape memory alloy wire 320 continues to contract. Since the shape memory alloy wire 320 passes through the channel on the outer sleeve 310, the contraction force is transmitted to the outer sleeve 310 through the contact between the wire and the channel wall, thereby driving the outer sleeve 310 to move downward, compressing the second elastic reset member 330, and realizing the unlocking drive. It is evident that the shape memory alloy wire 320 serves as both the trigger element for releasing the limit and the power source for driving the outer sleeve 310 to complete the unlocking process. The two work together to ensure the sequentiality and reliability of the unlocking process.

[0102] An axial guide structure is provided between the lower limiting cylinder 620 and the outer sleeve 310 to prevent relative rotation of the outer sleeve 310. Specifically, the axial guide structure includes an axial boss 622 located on the outside of the lower limiting cylinder 620 and an axial groove 317 located on the inside of the outer sleeve 310, with the axial boss 622 and the axial groove 317 slidingly engaged. This guide structure ensures that the outer sleeve 310 maintains circumferential positioning during axial sliding, preventing misalignment of the limiting ball 730 or the roller 400 due to rotation.

[0103] The contact surfaces of the outer casing 100 and the outer sleeve 310 are provided with a lubricating layer, such as a molybdenum disulfide lubricating layer. The inner wall of the channel through which the shape memory alloy wire 320 passes is provided with an insulating layer, such as a plastic bushing 321 or a high-temperature resistant ceramic insulating layer. It should be noted that the lubricating layer can reduce the sliding friction between the outer casing 100 and the outer sleeve 310, reducing unlocking resistance; the insulating layer can prevent the shape memory alloy wire 320 from short-circuiting or leaking electricity with the metal channel wall under high temperature or energized conditions.

[0104] The first elastic reset element 720 is a tension spring, the second elastic reset element 330 is a compression spring, and the third elastic reset element 520 is a compression spring. It can be understood that the tension spring provides tension to reset the limiting block 710, and the compression spring provides elasticity to reset the outer sleeve 310 and the separation cone 510. The specific types of the three elastic elements can be selected according to the actual load and space requirements, but are not limited to these.

[0105] This application also provides a locking and releasing method for a split nut locking and releasing device with anti-misunderstanding locking limit, the method including a locking state holding step, an unlocking step, and a reset step. Specifically, it includes the following steps:

[0106] S1. Locked state maintained;

[0107] In the locked state, the limiting block 710 presses upward against the limiting ball 730 under the action of the first elastic reset member 720, so that the limiting ball 730 is simultaneously located in the limiting groove 316 of the outer sleeve 310 and the receiving hole 624 of the lower limiting cylinder 620, forming a mechanical lock for the axial movement of the outer sleeve 310. At this time, the bolt to be locked is screwed into the split nut 200. The top of the split nut 200 abuts against the inclined surface of the top of the inner shell 100. The positioning structure 201 at the bottom of the split nut 200 cooperates with the limiting protrusion 511 of the separation cone 510 to jointly form an axial constraint on the split nut 200. At the same time, the roller 400 applies a radial constraint to the split nut 200, keeping the split nut 200 in a closed state, thereby achieving reliable locking of the bolt.

[0108] It should be noted that in this locked state, the shape memory alloy wire 320 is in a cooled and elongated state without being energized, and the first elastic reset member 720, the second elastic reset member 330 and the third elastic reset member 520 are all in a pre-compressed or pre-stretched state. The entire device does not consume any electrical energy and relies solely on a purely mechanical structure to resist external vibrations and impacts, preventing unintended unlocking.

[0109] S2, Unlock;

[0110] When it is necessary to loosen the bolts, perform the following sub-steps:

[0111] S201. When the shape memory alloy wire 320 is energized, it heats up due to the Joule heating effect, undergoes a martensitic-austenitic phase transformation, and contracts. Since the shape memory alloy wire 320 is connected to the limiting block 710 through the U-shaped channel 712 and passes through the channels on the outer sleeve 310 and the separation cone 510, its contraction force first acts on the limiting block 710.

[0112] S202, the shape memory alloy wire 320 overcomes the tension of the first elastic reset member 720, driving the limiting block 710 to move upward until the annular groove 711 on the limiting block 710 is aligned with the receiving hole 624 and the limiting groove 316. At this time, the limiting ball 730 can enter the annular groove 711 under the pushing action of the outer sleeve 310, releasing the constraint on the limiting groove 316, thereby releasing the axial limitation of the outer sleeve 310;

[0113] S203, the shape memory alloy wire 320 continues to contract, and its contraction force is transmitted to the outer sleeve 310 through the channel wall, driving the outer sleeve 310 to move downward, while compressing the second elastic reset member 330. During the downward movement of the outer sleeve 310, the roller 400 rolls downward with the outer sleeve 310, gradually releasing the radial constraint on the split nut 200;

[0114] S204. When the roller 400 moves completely to the separation groove 203 area on the outer wall of the split nut 200, the radial constraint of the split nut 200 is released. At this time, the third elastic reset member 520 releases its elastic force, pushing the separation cone 510 to move upward. The separation cone 510, through the cooperation of its limiting protrusion 511 with the positioning structure 201 at the bottom of the split nut 200, assists the split nut 200 to expand radially outward along the inclined surface at the top of the inner shell 100, so that the internal thread 202 of the split nut 200 disengages from the bolt. The bolt pops out under the action of the external preload, completing the unlocking.

[0115] It is understandable that the shrinkage of the shape memory alloy wire 320 in steps S202 and S203 is a continuous process. However, since the stroke required for the limit block 710 to move is much smaller than the stroke required for the outer sleeve 310 to move, and the resistance suddenly increases after the limit block 710 moves into place, the sequential action of "first releasing the limit and then driving the outer sleeve 310" is naturally realized without the need for additional control logic.

[0116] S3, Reset;

[0117] After unlocking, to restore the device to the locked ready state, perform the following sub-steps:

[0118] S301. Stop energizing the shape memory alloy wire 320. The shape memory alloy wire 320 cools naturally, transforms from austenite back to martensite, and gradually elongates back to its initial length.

[0119] S302. During the cooling and elongation process of the shape memory alloy wire 320, its contraction force gradually decreases. When the contraction force is less than the elastic force of the second elastic reset member 330, the second elastic reset member 330 pushes the outer sleeve 310 to move upward and reset. During the upward movement of the outer sleeve 310, the roller 400 rolls accordingly, gradually moving out of the separation groove 203 on the outer wall of the split nut 200 and reapplying radial constraint to the split nut 200, forcing the split nut 200 to close.

[0120] After the outer sleeve 310 is reset, the shape memory alloy wire 320 further cools and elongates, and its contraction force continues to decrease. When the contraction force is less than the tension of the first elastic reset member 720, the first elastic reset member 720 pulls the limiting block 710 downward to reset. During the downward movement of the limiting block 710, its outer side wall presses against the limiting ball 730 again, pushing the limiting ball 730 out of the annular groove 711, so that it is pressed against the limiting groove 316 and the receiving hole 624 again, restoring the axial locking of the outer sleeve 310.

[0121] At this point, the device is fully restored to the locked state, and the bolt can be screwed in again for repeated locking and use.

[0122] It should be noted that the entire reset process requires no manual intervention and is completed entirely by the automatic reset function of the first elastic reset component 720 and the second elastic reset component 330, thus realizing the reusability of the device.

[0123] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A split-nut locking and releasing device with anti-misunderstanding locking limit, characterized in that, include: The housing assembly, split nut, outer sleeve, lower limiting cylinder, limiting block, limiting ball, separation cone, and shape memory alloy wire; The lower limiting cylinder is fixedly disposed at the bottom of the housing assembly; The lower limiting cylinder has uniformly distributed receiving holes on its side wall for accommodating the limiting ball; The limiting block is axially movable inside the lower limiting cylinder, and the bottom of the limiting block is connected to the bottom of the housing assembly through a first elastic reset member. The outer side wall of the limiting block is provided with an annular groove for cooperating with the limiting ball; The outer sleeve is located inside the housing assembly, and the outer sleeve is slidably fitted onto the lower limiting sleeve along the axial direction; The inner wall of the outer sleeve is provided with a limiting groove for cooperating with the limiting ball; A second elastic reset element is provided between the outer sleeve and the lower limiting sleeve; The segmented nut is disposed inside the outer sleeve, and the top end of the segmented nut abuts against the inclined surface of the top of the housing assembly. The bottom end of the split nut is provided with a positioning structure; The separating cone is disposed inside the outer sleeve and is connected to the outer sleeve through a third elastic reset member; The separating cone is located below the split nut, and the separating cone is provided with a limiting protrusion that cooperates with the positioning structure to prevent the split nut from rotating. The outer sleeve is provided with a roller for radially limiting the split nut and axially rolling guide it; The limiting block is provided with a U-shaped channel; The shape memory alloy wire is threaded through the U-shaped channel, and the two ends of the shape memory alloy wire pass upward through the channels preset on the outer sleeve and the separation cone, respectively, and are then turned and fixed to the housing assembly by the guide. In the locked state, the limiting block presses against the limiting ball, keeping the limiting ball within the limiting groove and the receiving hole, preventing the outer sleeve from moving axially; the top end of the split nut abuts against the inclined surface at the top of the housing assembly, and the bottom end engages with the limiting protrusion of the separating cone, forming an axial constraint; the roller radially constrains the split nut. When the shape memory alloy wire contracts, it first drives the limiting block to move upward, so that the limiting ball enters the annular groove and releases the limiting of the outer sleeve; then it drives the outer sleeve to move downward, compressing the second elastic reset member, and the roller releases the radial constraint on the split nut. The split nut expands radially with the assistance of the third elastic reset member and the separating cone. After power failure, the second elastic reset member drives the outer sleeve to reset, and the first elastic reset member drives the limiting block to reset, so that the limiting ball is pressed back into the limiting groove and the receiving hole. The housing assembly includes an outer shell and a bottom cover that is removably mounted on the bottom of the outer shell; The lower limiting cylinder is fixedly installed on the top of the bottom end cover; The bottom end cap is also provided with an inner sleeve; The inner sleeve is located inside the lower limiting sleeve and is used to limit the bottom of the limiting block; The first elastic reset member is disposed inside the inner sleeve; The outer sleeve includes an integrally formed upper sleeve and a lower sleeve; The lower sleeve has the limiting groove on its inner wall; The inner wall of the upper sleeve is provided with a mounting groove for accommodating the roller; Both the split nut and the separating cone are disposed inside the upper sleeve; The upper sleeve has the channel at its bottom; The channel includes a vertical channel for connecting the upper sleeve and the lower sleeve, and a parallel channel for connecting the upper sleeve and the inner cavity of the housing assembly. The vertical channel is connected to the parallel channel; The bottom of the separation cone has a separation cone channel; The separating cone channel is connected to the vertical channel and the parallel channel; The two ends of the shape memory alloy wire pass upward through the vertical channel, the separation cone channel and the parallel channel respectively, and then are turned by the guide to pass out of the housing assembly, and finally fixed on the connecting post on the top outer side of the housing assembly.

2. The split nut locking and releasing device with anti-misinterpretation locking limit as described in claim 1, characterized in that, The positioning structure at the bottom of the split nut is a semi-cylindrical groove; The limiting protrusion on the separating cone is a semi-cylindrical protrusion that matches the shape of the semi-cylindrical groove.

3. The split nut locking and releasing device with anti-misunderstanding locking limit as described in claim 1, characterized in that, The guide component is an insulated pulley; The insulating pulley is fixedly mounted on the lower limiting cylinder or the bottom end cover.

4. The split nut locking and releasing device with anti-misinterpretation locking limit as described in claim 1, characterized in that, The number of shape memory alloy wires is two or more; Two or more of the shape memory alloy wires are arranged symmetrically. The number of the U-shaped channels, the channels, and the guides are matched with the number of the shape memory alloy wires, and are set in a one-to-one correspondence.

5. The split nut locking and releasing device with anti-misinterpretation locking limit as described in claim 1, characterized in that, An axial guide structure is provided between the lower limiting cylinder and the outer sleeve to prevent the outer sleeve from rotating relative to the cylinder. The axial guide structure includes an axial boss disposed on the outside of the lower limiting cylinder and an axial groove disposed on the inside of the outer sleeve. The axial boss slides into the axial groove.

6. The split nut locking and releasing device with anti-misinterpretation locking limit according to claim 1, characterized in that, The contact surface between the outer shell and the outer sleeve is provided with a lubricating layer, and / or the inner wall of the channel through which the shape memory alloy wire passes is provided with an insulating layer.

7. The split nut locking and releasing device with anti-misinterpretation locking limit according to claim 1, characterized in that, The first elastic reset element is a tension spring, the second elastic reset element is a compression spring, and the third elastic reset element is a compression spring.

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