A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod and its performance testing method

Abstract

A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod, relating to the field of spacecraft structures, includes an outer shell, an intermediate shell assembly, an inner shell, a gas generator, a self-unlocking component, and a chassis. The intermediate shell assembly is located inside the outer shell, and the inner shell is located inside the intermediate shell assembly. The intermediate shell assembly includes multiple shells nested sequentially. Any two adjacent shells form an outer shell and an inner shell. The top of the inner wall of the outer shell has a raised inner ring segment, and the inner ring segment has multiple rotating U-grooves arranged circumferentially. The outer wall of the inner shell is provided with cylindrical guide pins, which mate with the rotating U-grooves one by one. The chassis is fixedly connected to the bottom of the outer shell. The gas generator is connected to the middle of the chassis and extends into the inner shell. The self-unlocking component is located at the outlet of the gas generator so that the outlet of the gas generator opens after the self-unlocking component is unlocked. This invention solves the problems of large unlocking impact, large positioning impact, and excessive gap in the locking structure of existing multi-section deployable locking drag-reducing rod structures.

Description

Technical Field

[0001] This application belongs to the field of spacecraft structure technology, and provides a self-unlocking, self-buffering, retractable multi-section drag-reducing rod and a corresponding performance testing method. Background Technology

[0002] The underwater-launched spacecraft's helmet adopts a hydrodynamic, blunt-nosed shape. A virtual cone is formed at the top of the spacecraft using a retractable multi-section rod to reduce drag, a technique for aerodynamic load reduction after surfacing. The retractable rod structure proposed in patent "A High-Frequency, High-Damping Multi-Body Cantilever Telescopic Rod Structure with Top Plate" (application number 202318008466.6) represents the highest level of technology currently available domestically and internationally. However, it uses a pressure-shearing locking pin method for unlocking, lacks a buffer structure, and uses steps and large-deformation claw assemblies for positioning and locking. The resulting structure has a large pressure-shearing section before deployment, causing a large unlocking impact, excessively fast deployment speed, large positioning impact, and a large stopping gap after locking. The excessive positioning impact significantly affects the device body, continuously replenished pyrotechnics, and nearby sensitive sensors, potentially causing intermittent combustion of pyrotechnics and sensor damage. The excessive stopping gap also makes the system stiffness highly sensitive to load magnitude. Summary of the Invention

[0003] The technical problem solved by this application is to overcome the shortcomings of the prior art and provide a self-unlocking, self-buffering, retractable multi-section drag-reducing rod and a corresponding performance testing method, which solves the problems of large unlocking impact, large positioning impact, and excessive gap in the locking structure of the existing multi-section unfolding and locking drag-reducing rod structure.

[0004] This device features a reliable locking function and can achieve unpressurized unlocking followed by deployment using only high-pressure driving gas. It also utilizes an internal structure for compressed air self-buffering and rotational locking, offering advantages such as rapid unlocking, minimal unlocking impact, minimal impact upon reaching the target position, reliable locking, a compact locking structure, high system rigidity, insensitivity to loads, and easy disassembly. Furthermore, it provides repeatable test methods for verifying unlocking, deployment, locking, sealing performance, and modal damping characteristics.

[0005] The technical solution provided in this application is as follows:

[0006] A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod includes an outer shell, a middle shell assembly, an inner shell, a gas generator, a self-unlocking component, an anti-reverse-rotation component, and a chassis. The middle shell assembly is located inside the outer shell, and the inner shell is located inside the middle shell assembly. The middle shell assembly includes multiple shells that are nested together sequentially. Any two adjacent shells of the outer shell, the middle shell, and the inner shell form an outer shell and an inner shell. The top of the inner wall of the outer shell is provided with a raised inner ring section. The inner ring section is provided with multiple rotating U-grooves along the circumference. The rotating U-grooves include a semi-circular section and a horizontal section. The semi-circular section is an arc-shaped groove with a central angle of 90 degrees. One end of the semi-circular section extends to the bottom edge of the inner ring section and is perpendicular to the bottom edge of the inner ring section. The other end of the semi-circular section is connected to the horizontal section. Extending circumferentially along the inner ring section; cylindrical guide pins are provided on the outer wall of the inner shell, and the cylindrical guide pins mate with the rotating U-grooves one by one; a raised outer ring section is provided at the bottom of the outer wall of the inner shell, and the outer ring section is provided with axially distributed sealing ring grooves for placing O-rings; the chassis is fixedly connected to the bottom inside the outer shell, the outer shell and the inner shell are located above the chassis, the gas generator is fixedly connected to the middle of the chassis and extends into the inner shell, the self-unlocking component is provided at the outlet position of the gas generator so that the outlet of the gas generator opens after the self-unlocking component is unlocked; the anti-reverse rotation component is installed on the inner ring section and is located at the junction of the semi-circular section and the transverse section so that after the cylindrical guide pin enters the transverse section, it locks the cylindrical guide pin in the transverse section.

[0007] The bottom of the inner wall of the inner ring section is provided with multiple air guide U-grooves, and the upper part of the air guide U-grooves is provided with throttling and venting holes, which are connected to the inner and outer sides of the outer shell.

[0008] The inner ring section is provided with an anti-reverse rotation component mounting hole, which includes an upper threaded hole and a lower square hole. The anti-reverse rotation component includes a clamping pin and a square tongue. The clamping pin is a rotary stepped shaft structure with a threaded column at the top and an elastic push rod at the bottom. The square tongue has a positioning plate at the top and a square column-shaped tongue body at the bottom. The lower end face of the tongue body is a wedge-shaped inclined surface. Along the circumferential direction of the inner ring section, the end of the inclined surface near the semicircular section is lower than the end near the horizontal section. The tongue body passes through the square hole, the positioning plate is located above the square hole, the threaded column is threaded into the threaded hole, and the elastic push rod is in contact with the positioning plate.

[0009] The semicircular segment extends to the bottom edge of the inner ring segment, which is the entrance end, and rounded corners are provided on both sides of the entrance end.

[0010] The gas generator has an ignition chamber, a combustion chamber, a gas passage, and a valve seat chamber arranged sequentially from bottom to top. The combustion chamber contains a gunpowder block, which generates a large amount of high-temperature gas when burning. The ignition chamber is used to install an ignition device to ignite the gunpowder block. The valve seat chamber extends to the top of the gas generator and has multiple evenly distributed vent holes around its circumference. The vent hole axes are along the radial direction of the gas generator and extend to the outer wall of the gas generator. A self-unlocking component is installed in the valve seat chamber. The high-temperature gas generated when the gunpowder block burns enters the self-unlocking component in the valve seat chamber through the gas passage. When the self-unlocking component is opened, the vent holes are opened.

[0011] The self-unlocking assembly includes a pull rod, a hook, a ring frame, a valve core push rod, a hook shaft, and a sealing cap. A transverse partition is provided inside the inner shell, with the gas generator located on the side of the transverse partition facing the chassis. One end of the pull rod is connected to the transverse partition, and the other end is a lower end plate used to connect the hook. The ring frame is threaded to the circumferential surface of the valve seat cavity inner wall. The ring frame has multiple vent holes that correspond one-to-one with the air outlet holes. The upper part of the ring frame has a cross-shaped hook fixing groove. Below the hook fixing groove, the ring frame has a middle end plate and a valve core cavity arranged sequentially. A top positioning through hole is provided at the axial position of the middle end plate, connecting the hook fixing groove and the valve core cavity. The valve core push rod includes a straight column section, a push rod, and a valve core body connected sequentially. The end of the straight column section away from the push rod is a ball head surface, and the end of the valve core body opposite to the push rod is... The valve core has a recessed groove, and the valve core body is located inside the valve core cavity. The top of the straight column section passes through the top positioning through hole and extends into the center position of the hook fixing groove. The limiting ring is set between the valve core body and the middle end plate. One end of the hook is located in the hook fixing groove and is rotatably connected to the ring frame so that the top of the hook can approach or move away from the axis of the valve core rod. The hook facing the axis of the valve core rod has a retaining surface, an incised conical surface and a claw head arranged sequentially from bottom to top. When the retaining surface is in close contact with the straight column section, the claw head hooks onto the upper surface of the lower end plate. Along the direction away from the retaining surface, the incised conical surface gradually approaches the axis of the valve core rod relative to the plane where the retaining surface is located. As the valve core rod moves upward, the ball head surface contacts the incised conical surface and gradually pushes the hook to rotate, so that the top of the hook can move away from the axis of the valve core rod.

[0012] The pull rod includes a threaded section, a positioning ring, a pull rod body, and a lower end plate arranged sequentially along its own axis. The positioning ring is located on the side of the transverse diaphragm facing the chassis, and the end of the threaded section that passes through the transverse diaphragm is threadedly connected to a sealing cap.

[0013] When installing the self-unlocking component, the hook is installed in the hook fixing groove of the ring frame, the limit ring and valve core top rod are installed into the valve core cavity, and the claw head is pressed against the lower end plate. The ring frame with the limit ring and valve core top rod is installed into the valve seat cavity. The gas generator is installed on the chassis, and the threaded section of the pull rod passes through the transverse partition. The sealing cover is connected to the threaded section, so that the pull rod is tightened to form axial preload.

[0014] The chassis is a rotating ring structure, with a cylindrical structure in the middle. The inner wall of the cylindrical structure is provided with threaded holes, and the top of the cylindrical structure is an inward-turning ring. There is a sealing disc on the outer circumference of the gas generator. A sealing ring groove is provided on the upper end face of the sealing disc. The inward-turning ring is locked in the sealing ring groove. On the side of the cylindrical structure away from the inward-turning ring, an anti-loosening pressure ring and a threaded pressure ring are sequentially threaded through threaded holes.

[0015] A performance testing method for a self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod includes an inflation deployment test and a non-contact modal test.

[0016] The inflation and deployment test includes: the drag-reducing rod is fixed to the test bracket through the outer shell; an inflation fixture is installed in the middle of the drag-reducing rod's chassis; the structure of the inflation fixture is consistent with that of the gas generator and the self-unlocking component; no gunpowder is installed inside the inflation fixture; the inflation fixture is connected to the gas source through an inflation passage; a switch F1 and a pressure measuring device are connected sequentially along the airflow direction on the inflation passage; a venting passage is connected between the inflation passage and the pressure measuring device; a switch F2 is connected to the venting passage; compressed air or nitrogen is injected into the drag-reducing rod; when the drag-reducing rod begins to unlock, the pressure inside the drag-reducing rod is recorded by the pressure measuring device, which is the unlocking pressure value Pj. After the drag-reducing rod begins to unfold, continue to slowly fill it with compressed air or nitrogen without depressurizing until the drag-reducing rod is fully unfolded. Record the pressure change process during unfolding and the pressure value inside the drag-reducing rod when it is fully unfolded. Continue to fill it with compressed air or nitrogen until the pressure inside the drag-reducing device reaches the set pressure P0. Close the air filling passage F1 and the air venting passage F2 and conduct an airtightness test on the drag-reducing device. During the airtightness test, continuously record the pressure change inside the drag-reducing device. No pressure change indicates good airtightness performance.

[0017] The non-contact modal test includes: the deployed drag-reducing rod is fixed to the test stand via a shell, and air is injected into the rod to a set pressure P0 using an inflation fixture. Then, a vibration device is used to sweep frequencies according to a random vibration process, while a laser micrometer measures the vibration micro-displacement process at characteristic positions of the drag-reducing rod. Several modes are measured by the correlation between vibration amplitude and frequency changes. The Modal Decision Criterion (MAC) is then used to analyze the correlation between mode shapes. The first-order frequency value f1 is determined based on the first frequency at which the drag-reducing rod resonates. Finally, the vibration device is used to excite the rod in a sinusoidal vibration mode on both sides of the narrow band f1 frequency to determine the precise value of f1.

[0018] The advantages of this invention are:

[0019] (1) The device has a reliable locking function and can achieve unlocking and unfolding without pressure buildup using only high-pressure driving gas. It has the advantages of quick unlocking and small unlocking impact.

[0020] (2) The internal structure is used to achieve compressed air self-buffering and rotational locking, which has the advantages of small impact when in place and reliable locking.

[0021] (3) The locking structure is compact, with no gap in either direction, and the overall system has high stiffness and is not sensitive to load;

[0022] (4) The use of an exposed and easily disassembled anti-rotation component allows for convenient disassembly of the device, which is conducive to reuse.

[0023] (5) A complete set of test methods is provided for repeatable verification of unlocking, unfolding, locking, sealing performance and modal damping characteristics. Attached Figure Description

[0024] Figure 1 Schematic diagram of a self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod structure;

[0025] Figure 2 This is a schematic diagram of the outer shell structure;

[0026] Figure 3 This is a schematic diagram of the intermediate shell assembly structure.

[0027] Figure 4 This is a schematic diagram of the inner shell structure.

[0028] Figure 5 This is a schematic diagram of the gas generator structure.

[0029] Figure 6 Schematic diagram of threaded pressure ring, locking pressure ring and tightening fixture;

[0030] Figure 7 This is a schematic diagram of the self-unlocking component structure.

[0031] Figure 8 This is a schematic diagram of the tie rod structure.

[0032] Figure 9 This is a schematic diagram of the hook-and-claw structure.

[0033] Figure 10 This is a schematic diagram of the ring frame structure.

[0034] Figure 11 This is a schematic diagram of the valve core push rod structure.

[0035] Figure 12 This is a schematic diagram of the limiting ring structure;

[0036] Figure 13 This is a schematic diagram of the sealing gland structure.

[0037] Figure 14 This is a schematic diagram illustrating the working principle of the self-unlocking component.

[0038] Figure 15Diagram showing the structure and working principle of the anti-reverse rotation component;

[0039] Figure 16 This is a schematic diagram of the inflatable deployment test method.

[0040] Figure 17 This is a schematic diagram of the non-contact modal testing method. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0042] This application discloses a self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod, such as... Figure 1 As shown, it consists of an outer shell 1, an intermediate shell assembly 2, an inner shell 3, a gas generator 4, a self-unlocking assembly 5, an anti-reverse rotation assembly 6, a chassis 7, a threaded pressure ring 8, and an anti-loosening pressure ring 9.

[0043] like Figure 2 As shown, the outer shell 1 is a rotating structure, with a flange face 1.1 at the top and a cylindrical section 1.2 at the bottom. Sixteen rotating U-grooves 1.3 are provided on the inner side of the upper part of the cylindrical section. Each rotating U-groove consists of a semi-circular section and a horizontal section, with large rounded corners on both sides of the inlet. On the upper part of the cylindrical section, on the lower structure of the rotating U-grooves, four air-guiding U-grooves 1.4 are provided on the inner side, and four throttling and venting holes 1.5 are provided on the upper part of the air-guiding U-grooves, connecting the inside and outside of the outer shell. On the inner side of the flange face, anti-reverse rotation component mounting holes are provided at the junction of the upper semi-circular section and the horizontal section of the four rotating U-grooves, including an upper M3 threaded hole 1.6 and a lower square hole 1.7.

[0044] like Figure 3 As shown, the intermediate shell assembly 2 comprises seven nested shells with essentially identical structures, all being rotating sleeve structures, differing only in their inner and outer diameters. Each intermediate shell structure includes a sleeve section 2.1, an upper inner ring section 2.4, and a lower outer ring section 2.2. The outer ring section 2.2 has two axially distributed sealing ring grooves 2.3 on its outer circumferential surface to accommodate O-rings, forming a double-layer sealing structure. The inner ring section 2.4 has circumferentially distributed rotating U-grooves 2.7, consisting of a semi-circular section and a horizontal section, with large rounded corners on both sides of the inlet. From the outside in, the number of rotating U-grooves in each intermediate shell is 16, 16, 12, 12, 8, 8, and 6 respectively, determined primarily by the load-bearing capacity and structural parameters of each section. Outside the rotating U-grooves of the inner ring section, four air-guiding, throttling, and pressure-relief structures 2.6 are located on the inner side. At the top, anti-reverse rotation assembly mounting holes 2.5 are provided at the junction of the upper semicircular section and the horizontal and vertical section of the four rotating U-grooves. Evenly distributed cylindrical guide pins 2.8 are provided on the lower outer circumference of the sleeve section. The number of cylindrical guide pins 2.8 is consistent with the number of rotating U-grooves on the outer mating shell section.

[0045] like Figure 4 As shown, the inner shell 3 is a rotating sleeve structure. The upper middle part of the outer shell 3.1 has a transverse partition 3.3, which separates the upper and lower cavities. The lower cavity houses the gas generator and participates in forming the sealed cavity of the device. The middle of the transverse partition has a through hole 3.4 for connecting the pull rod of the self-unlocking component 5. Six cylindrical guide pins 3.5 are evenly distributed on the lower outer circumference. The bottom is an outer ring section 3.6, and two axially distributed sealing ring grooves 3.7 are provided on the outer circumference of the outer ring section.

[0046] In summary, the above structure can be described as follows: any two adjacent shells 1, 3, and 4 form an outer shell and an inner shell. The top of the inner wall of the outer shell is provided with a raised inner ring segment. The inner ring segment is provided with multiple rotating U-grooves along the circumference. The rotating U-grooves include a semi-circular segment and a horizontal segment. The semi-circular segment is an arc-shaped groove with a central angle of 90 degrees. One end of the semi-circular segment extends to the bottom edge of the inner ring segment and is perpendicular to the bottom edge of the inner ring segment. The other end of the semi-circular segment is connected to the horizontal segment, which extends along the circumference of the inner ring segment. The outer wall of the inner shell is provided with cylindrical guide pins, which mate with the rotating U-grooves one by one. The bottom of the outer wall of the inner shell is provided with a raised outer ring segment. The outer ring segment is provided with axially distributed sealing ring grooves for placing O-rings. The difference between the inner diameter of the top of the outer shell and the outer diameter of the top of the inner shell is less than 0.01 mm, making it difficult for gas between two adjacent outer and inner shells to escape from their gap. Therefore, a throttling vent is further provided so that gas between the outer and inner shells can be further discharged through the throttling vent.

[0047] like Figure 5 As shown, the gas generator 4 has a rotary tube structure. The lower middle part is the combustion chamber 4.2, which contains a propellant block that generates a large amount of high-temperature gas during combustion. The bottom contains an ignition chamber 4.6, an ignition port 4.5, and a pressure measuring port 4.7. A sealing disc 4.3 is located on the lower outer circumference, with a sealing ring groove 4.4 on its upper end face to form an end-face seal with the inner disc of the bottom cover. The upper part of the combustion chamber is a cooling section 4.1. A gas passage 4.8 within the cooling section introduces the high-temperature gas generated in the combustion chamber into the upper valve seat cavity 4.9. The valve seat cavity 4.9 has eight evenly distributed vent holes 4.11 around its circumference, and the total diameter area of ​​the vent holes 4.11 is more than three times that of the gas passage 4.8. The bottom of the valve seat cavity 4.9 is a valve face 4.12 with internal threads on its circumference for connecting the ring bracket of the self-unlocking assembly.

[0048] like Figure 7 As shown, the self-unlocking component 5 includes a pull rod 11, a hook 12, a ring frame 13, a valve core push rod 14, a limit ring 15, a hook shaft 16, and a sealing cover 17.

[0049] like Figure 8As shown, the pull rod 11 is a rotating rod-shaped structure, with a threaded section 11.1 at the top, a positioning ring 11.2 at the upper middle, a pull rod body 11.3 in the middle, and a lower end plate 11.4 at the bottom. The lower end plate 11.4 has a semi-circular structure around its perimeter.

[0050] like Figure 9 As shown, the claw 12 has a long strip structure, with a claw head 12.1 at the top and a flat surface at the bottom. The middle part of the claw is an inwardly tapered surface 12.2, the lower part is a retaining surface 12.3, and the lower rear part is a pin hole 12.4.

[0051] like Figure 10 As shown, the ring frame 13 is a rotating sleeve structure. The upper part has a cross-shaped hook-claw fixing groove 13.1, with a threaded shaft hole 13.2 passing through the middle of the hook-claw fixing groove 13.1. A large-diameter through hole 13.3 is located outside the threaded shaft hole. The middle of the ring frame has a middle end plate 13.4, with a top positioning through hole 13.5 in the middle. The lower side of the ring frame is the valve core cavity 13.6, with eight circumferentially distributed vent holes 13.7 at the bottom. The outer circumferential surface of the ring frame has fine-pitch threads 13.8, used to fix the ring frame in the valve seat cavity 4.9 of the gas generator.

[0052] like Figure 11 As shown, the valve core push rod 14 is a rotary stepped shaft structure. Its top end is a ball-head surface 14.1, and the upper middle part is a straight column section 14.2, which transitions tangentially to the ball-head surface. The middle part of the valve core push rod 14 is the push rod 14.3, the difference in radius between which is equal to the radius of the straight column section 14.2, and the retraction stroke of the retaining surface 12.3 of the hook 12 is consistent with the total stroke. The lower part of the valve core push rod is the valve core body 14.5, and the upper end face of the valve core body is the position maintaining surface 14.4.

[0053] like Figure 12 As shown, the limiting ring 15 is a thin-shell labyrinth-shaped rotating body or a concave hexagonal lattice. Its outer circumferential surface 15.1 is placed inside the valve core cavity 13.6, and its inner circumferential surface 15.2 is fitted onto the outside of the push rod 14.3. The upper end surface 15.3 of the limiting ring is tightly attached to the lower end surface of the middle end plate 13.4, and the lower end surface 15.4 is tightly attached to the position maintaining surface 14.4 of the valve core push rod. After being compressed, its height H becomes 1 / 3 of its original value.

[0054] The claw shaft 16 is a rotating rod structure with a threaded end and a smooth shaft at the other end.

[0055] like Figure 13As shown, the sealing cap 17 has a rotary disc structure. The upper part of the disc body 17.1 is a sealing cap 17.2, which, after tightening, ensures no gas leakage directly from the threaded section 11.1. The disc body has a threaded hole 17.3 in the middle. After tightening with the threaded section 11.1 of the pull rod, the lower end face 17.4 is pressed tightly against the upper end face of the transverse partition 3.3 of the inner shell. Two annular sealing ring grooves 17.5 are provided on the lower end face of the sealing cap. When the sealing rings and transverse partition 3.3 are pressed tightly together, a redundant sealing structure is formed, ensuring no gas leakage from the inner cavity of the device. The outer circumferential surface of the sealing cap 17 has multiple tightening surfaces 17.6 for tightening.

[0056] When the self-unlocking component 5 is installed, the four hooks 12 are positioned within the hook fixing grooves 13.1 of the ring frame. The hook shaft 16 is screwed into the large-diameter through hole 13.3 of the ring frame, and then passes through the threaded shaft hole 13.2 and the pin hole 12.4 in sequence, and is tightened to complete the fixation. The claw heads 12.1 of the circumferentially distributed hooks grip and press against the lower end plate 11.4 of the pull rod. At the same time, the lower end of the hook is limited by the straight column section 14.2 of the valve core push rod in the middle and cannot be turned outward, that is, the pull rod 11 will not be released. The valve core push rod 14 is axially pressed against the valve face 4.12 of the gas generator by the limiting ring 15 and the ring frame 13. When high-pressure gas is not introduced, there will be no axial movement, that is, no false locking, ensuring good environmental adaptability. After the threaded section 11.1 of the pull rod passes through the through hole 3.4 of the inner shell, the threaded hole 17.3 of the sealing cap 17 is screwed into the threaded section 11.1, pressing the transverse diaphragm end face of the inner shell, tightening the pull rod 11 to form axial preload, and forming a good seal.

[0057] like Figure 14 As shown, the self-unlocking component works as follows: When the gas generator 4 is ignited, the high-pressure gas generated in the combustion chamber enters the lower part of the valve core push rod 14 along the gas passage 4.8, then pushes the valve core push rod 14 upward and crushes the limiting ring 15. Then, the straight column section 14.2 of the valve core push rod disengages from the retaining surface 12.3 of the hook, and the ball head surface 14.1 pushes the inwardly inclined conical surface 12.2 of the hook, pushing the hook 12 outward, thus unlocking the lower end plate of the pull rod 11. Then, the high-pressure gas passes through the opened lower part of the valve core, enters the inner cavity of the inner shell 3 through the vent hole 13.7 and the outlet hole 4.11, and drives the drag-reducing rod to unfold. This achieves the function of unlocking first and then unfolding.

[0058] like Figure 15As shown, the anti-reverse rotation assembly 6 includes a clamping pin 21 and a square tongue 22. The clamping pin 21 is a rotary stepped shaft structure, with a threaded post 21.2 at the top and an elastic push rod 21.3 at the bottom, and a square wrench hole 21.1 at the top. The square tongue 22 has a positioning plate 22.1 at the top and a square columnar tongue body 22.2 at the bottom, with a wedge-shaped inclined surface 22.3 at the bottom end of the tongue body. During installation, the square tongue is placed into the square hole of the anti-reverse rotation assembly mounting hole on the upper end face of each housing, and then the clamping pin 21 is screwed into the M3 threaded hole until the elastic push rod clamps the positioning plate of the square tongue. During operation, when the cylindrical guide pin on the housing is screwed into the rotating U-groove of the outer shell, the trajectory is as shown by arrow 2.8. When the cylindrical guide pin enters the straight section, it pushes the inclined surface 22.3 upward and compresses the elastic push rod 21.3. When the cylindrical guide pin enters the straight section, the elastic push rod pushes the square tongue back into place. The square tongue is engaged with the other side of the highest point of the cylindrical guide pin, which cooperates with the reverse inclined surface 22.3 to effectively prevent the shell from retracting due to vibration or other reasons, thus achieving the anti-reverse rotation effect.

[0059] like Figure 1 As shown, the chassis 7 is a rotating annular structure. A threaded hole 7.1 is provided in the center, and an inner folding ring 7.2 is connected to the center of the chassis 7. The top of the inner folding ring 7.2 mates with a sealing ring groove 4.4. A sealing groove is formed on the outer circumferential surface of the chassis 7, and a sealing ring is installed within the sealing groove to seal the outer circumferential surface between the outer shell 1 and the chassis 7. Multiple connecting holes are formed at the bottom of the outer circumferential surface of the outer shell 1, and connecting bolts pass through these connecting holes and connect to the chassis 7. The connecting bolts are located below the sealing ring.

[0060] like Figure 6 As shown, the threaded pressure ring 8 is a rotating annular structure. Its outer circumferential surface is the threaded surface 8.1, its bottom is the bottom end surface 8.2, and its upper part has a spacer groove 8.3 for rotational installation using a corresponding spacer tool. The top is the top end surface 8.4. The threaded hole 7.1 mates with the threaded surface of the outer circumferential surface of the threaded pressure ring 8.

[0061] The anti-loosening pressure ring 9 is a short, rotating ring structure. The outer circumferential surface is a threaded surface 9.1, the bottom is a bottom end surface 9.2, and the upper part is provided with a spacer groove 9.3. It is rotated and installed using a corresponding spacer tooth tool. The threaded hole 7.1 mates with the threaded surface of the outer circumferential surface of the anti-loosening pressure ring 9.

[0062] During installation, the gas generator 4 is passed through the threaded hole 7.1 of the chassis 7 until the upper end face of the sealing disc 4.3 is flush with the lower end face of the inner ring 7.2. At this time, the threaded section 11.1 of the pull rod in the self-unlocking assembly 5 at the top of the gas generator passes through the through hole 3.4 of the inner shell, and then the sealing cap 17 is tightened from the top. Then, the threaded pressure ring 8 is screwed into the threaded hole 7.1 of the chassis until it presses against the sealing disc 4.3 of the gas generator. Then, the anti-loosening pressure ring 9 is screwed into the threaded hole 7.1 of the chassis until its bottom end face 9.2 presses against the top end face 8.4 of the threaded pressure ring, forming a double-nut anti-loosening structure.

[0063] The overall working principle is as follows: after the gas generator drives the self-unlocking component to unlock, high-pressure gas enters the inner cavity of the drag-reducing rod, pushing each component to unfold. During the unfolding process, a circumferential sealed cavity is formed between two adjacent shells, and gas can only be slowly exhausted through the throttling vent holes of each shell section. When the inner shell is about to unfold into place, the pressure in the outer sealed cavity is already high, which can create a gas blocking effect, decelerating and buffering the high-speed movement of the inner shell. This also prevents the inner shell from rebounding during exhaust. At the end of its slow movement, the cylindrical guide pin of the inner shell enters the rotating U-groove of the outer shell and rotates to the horizontal locking position, completing the unfolding process.

[0064] A performance testing method for a self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod is provided. Since the performance of the drag-reducing rod includes unlocking performance, deployment performance, sealing performance, and modal damping, it is measured through an inflation deployment test and a non-contact modal test.

[0065] like Figure 16 As shown, the inflation and deployment test method is as follows: The outer shell 1 of the drag-reducing rod is fixed on the test bracket. An inflation fixture with the same structure as the gas generator 4 and the self-unlocking component 5 is installed in the middle of the chassis 7. No gunpowder is installed inside the inflation fixture. The inflation fixture is connected to the gas source through an inflation passage. A switch F1 and a pressure measuring device are connected sequentially along the airflow direction on the inflation passage. A venting passage is connected between the inflation passage and the pressure measuring device, and a switch F2 is connected to the venting passage. The internal pressure of the drag-reducing rod is measured by the pressure measuring device. In this embodiment, the pressure measuring device is a pressure gauge. It should be ensured that there is no air leakage in the inflation pipeline during the test. Compressed air / nitrogen is injected into the drag-reducing rod. When the drag-reducing rod begins to unlock, the internal pressure of the drag-reducing rod is recorded. After the drag-reducing rod begins to deploy, compressed air / nitrogen is continued to be slowly injected without depressurizing until the drag-reducing rod is fully deployed (deployment stroke 1.8m). The pressure change process during deployment and the internal pressure value of the drag-reducing rod when it is fully deployed are recorded. Continue filling with compressed air / nitrogen until the pressure inside the drag reduction device reaches 0.45 MPa (gauge pressure). Close the filling and venting passages and perform an airtightness test on the drag reduction device. The test lasts for 3 minutes, and the pressure change inside the drag reduction device is continuously recorded.

[0066] like Figure 17 As shown, the non-contact modal testing method is as follows: the drag reduction device in the deployed state is installed on a special fixed support fixture, and air is injected into the rod through an inflation fixture. Then, a laser micrometer is used to measure the vibration displacement process at the characteristic position of the drag reduction rod.

[0067] The contents not described in detail in this application specification are common knowledge to those skilled in the art.

[0068] The present application has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present application. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod, characterized in that: It includes an outer shell (1), an intermediate shell assembly (2), an inner shell (3), a gas generator (4), a self-unlocking assembly (5), an anti-reverse rotation assembly (6), a chassis (7), a threaded pressure ring (8), and an anti-loosening pressure ring (9). The intermediate shell assembly (2) is located inside the outer shell (1), and the inner shell (3) is located inside the intermediate shell assembly (2). The intermediate shell assembly (2) includes multiple shells that are nested together in sequence. In the outer shell (1), the outer shell and the inner shell (3), any two adjacent shells form an outer shell and an inner shell. The top of the inner wall of the outer shell is provided with a raised inner ring section. The inner ring section is provided with multiple rotating U-grooves along the circumference. The rotating U-grooves include a semi-circular section and a horizontal section. The semi-circular section is an arc-shaped groove with a central angle of 90 degrees. One end of the semi-circular section is perpendicular to the bottom edge of the inner ring section and extends through to the bottom edge of the inner ring section. The other end of the semi-circular section is connected to the horizontal section. The horizontal section extends along the circumference of the inner ring section. The outer wall of the inner shell is provided with a cylindrical guide pin. The cylindrical guide pin is matched with the rotating U-grooves one by one. The bottom of the outer wall of the inner shell is provided with a raised outer ring section. The outer ring section is provided with axially distributed sealing ring grooves. The sealing ring grooves are used to place O-rings. The chassis (7) is fixedly connected to the bottom of the outer shell (1). The outer shell and inner shell (3) are located above the chassis (7). The gas generator (4) is fixedly connected to the middle of the chassis (7) and extends into the inner shell (3). It is pressed by the threaded pressure ring (8) and locked by the anti-loosening pressure ring (9). The self-unlocking component (5) is set at the outlet position of the gas generator (4) so ​​that the outlet of the gas generator (4) opens after the self-unlocking component (5) is unlocked. The anti-reverse rotation component (6) is installed in the inner ring section and located at the junction of the semi-circular section and the horizontal section so that the cylindrical guide pin is locked in the horizontal section after it enters the horizontal section. The gas generator (4) has an ignition chamber (4.6), a combustion chamber (4.2), a gas passage (4.8), and a valve seat chamber (4.9) arranged sequentially from bottom to top. The combustion chamber (4.2) contains a gunpowder block, which generates a large amount of high-temperature gas when burning. The ignition chamber (4.6) is used to install an ignition device to ignite the gunpowder block. The valve seat chamber (4.9) extends to the top of the gas generator (4). The valve seat chamber (4.9) is circumferentially provided with multiple evenly distributed air outlets (4.11). The axis of the air outlets (4.11) is along the radial direction of the gas generator (4) and extends to the outer wall of the gas generator (4). The self-unlocking component (5) is installed in the valve seat chamber (4.9). The high-temperature gas generated when the gunpowder block burns enters the self-unlocking component (5) in the valve seat chamber (4.9) through the gas passage (4.8). When the self-unlocking component (5) is opened, the air outlets (4.11) are opened. The self-unlocking assembly (5) includes a pull rod (11), a hook (12), a ring frame (13), a valve core push rod (14), a hook shaft (16), and a sealing cap (17). The inner shell (3) is provided with a transverse partition (3.3). The gas generator (4) is located on the side of the transverse partition (3.3) facing the chassis (7). One end of the pull rod (11) is connected to the transverse partition (3.3), and the other end of the pull rod (11) is a lower end plate (11.4), which is used to connect the hook (12). The ring frame (13) is threaded to the circumferential surface of the inner wall of the valve seat cavity (4.9). The ring frame (13) has multiple vent holes that are directly opposite the air outlet (4.11). (13.7) The upper part of the ring frame (13) is a cross-shaped hook fixing groove (13.1). The ring frame (13) is provided with a middle end plate (13.4) and a valve core cavity (13.6) below the hook fixing groove (13.1). The middle end plate (13.4) is provided with a top positioning through hole (13.5) at the axial position. The top positioning through hole (13.5) connects the hook fixing groove (13.1) and the valve core cavity (13.6). The valve core push rod (14) includes a straight column section (14.2), a push rod (14.3) and a valve core body (14.5) connected in sequence. The end of the straight column section (14.2) away from the push rod (14.3) is a ball head surface (14.1). The valve core body (14.5) has a recessed groove at one end away from the top rod (14.3). The valve core body (14.5) is located in the valve core cavity (13.6). The top end of the straight column section (14.2) passes through the top positioning through hole (13.5) and extends into the center position of the hook fixing groove (13.1). The limiting ring (15) is set between the valve core body (14.5) and the middle end plate (13.4). One end of the hook (12) is located in the hook fixing groove (13.1) and is rotatably connected to the ring frame (13) so that the top of the hook (12) can approach or move away from the axis of the valve core top rod (14). The hook (12) is arranged from bottom to top on the side facing the axis of the valve core top rod (14). The retaining surface (12.3), the inclined conical surface (12.2), and the claw head (12.1) are engaged with the straight column section (14.2). When the retaining surface (12.3) is in contact with the straight column section (14.2), the claw head (12.1) hooks onto the upper surface of the lower end plate (11.4). Along the direction away from the retaining surface (12.3), the inclined conical surface (12.2) gradually moves towards the axis of the valve core rod (14) relative to the plane where the retaining surface (12.3) is located. As the valve core rod (14) moves upward, the ball head surface (14.1) contacts the inclined conical surface (12.2) and gradually pushes the claw (12) to rotate, so that the top of the claw (12) can move away from the axis of the valve core rod (14).

2. The self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The bottom of the inner wall of the inner ring section is provided with multiple air guide U-grooves, and the upper part of the air guide U-grooves is provided with throttling and venting holes, which are connected to the inner and outer sides of the outer shell.

3. The self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The inner ring section is provided with an anti-reverse rotation component mounting hole, which includes an upper threaded hole and a lower square hole. The anti-reverse rotation component (6) includes a clamping pin (21) and a square tongue (22). The clamping pin (21) is a rotating stepped shaft structure, with a threaded column (21.2) at the top and an elastic push rod (21.3) at the bottom. The square tongue (22) has a positioning plate (22.1) at the top and a square column-shaped tongue (22.2) at the bottom. The lower end face of the tongue is a wedge-shaped inclined surface (22.3). Along the circumferential direction of the inner ring section, the end of the inclined surface (22.3) near the semicircular section is lower than the end near the horizontal section. The tongue (22.2) passes through the square hole. The positioning plate (22.1) is located above the square hole. The threaded column (21.2) is threaded into the threaded hole. The elastic push rod (21.3) is in contact with the positioning plate (22.1).

4. The self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The semicircular segment extends to the bottom edge of the inner ring segment, which is the entrance end, and rounded corners are provided on both sides of the entrance end.

5. The self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The total diameter area of ​​the gas outlet (4.11) is more than three times the cross-sectional area of ​​the gas passage (4.8).

6. The self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The pull rod (11) includes a threaded section (11.1), a positioning ring (11.2), a pull rod body (11.3), and a lower end plate (11.4) arranged sequentially along its own axis. The positioning ring (11.2) is located on the side of the transverse partition (3.3) facing the chassis (7). The end of the threaded section (11.1) that passes through the transverse partition (3.3) is threadedly connected to a sealing cap (17).

7. A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 6, characterized in that: When installing the self-unlocking component (5), the hook (12) is installed in the hook fixing groove (13.1) of the ring frame, the limiting ring (15) and the valve core push rod (14) are installed into the valve core cavity (13.6), and the claw head (12.1) is pressed against the lower end plate (11.4). The ring frame (13) with the limiting ring (15) and the valve core push rod (14) is installed into the valve seat cavity (4.9). The gas generator (4) is installed on the chassis (7), and the threaded section (11.1) of the pull rod passes through the transverse partition (3.3). The sealing cover (17) is connected to the threaded section (11.1), so that the pull rod (11) is tightened to form an axial preload.

8. A self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod according to claim 1, characterized in that: The chassis (7) is a rotating ring structure, the middle part of which is a cylindrical structure. The inner wall of the cylindrical structure is provided with a threaded hole (7.1), and the top of the cylindrical structure is an inward-turning ring (7.2). The outer circumferential surface of the gas generator (4) has a sealing disc (4.3). The upper end face of the sealing disc is provided with a sealing ring groove (4.4). The inward-turning ring (7.2) is locked in the sealing ring groove (4.4). On the side of the sealing disc (4.3) away from the inward-turning ring (7.2), the cylindrical structure is connected to the anti-loosening pressure ring (9) and the threaded pressure ring (8) in sequence through the threaded hole (7.1). The threaded pressure ring (8) is a ring-shaped rotating body structure with a pressure plane (8.2) at the front end, a spacer groove (8.3) at the rear end, and an external thread (8.1) on the outer circumference. During installation, a tightening tool (10) is used, with its central hole (10.2) passing through the lower cylindrical section (4.13) of the gas generator (4), and its front teeth (10.1) inserted into the spacer groove (8.3). Then, a sleeve is used to fit onto the square section (4.14) of the gas generator (4) to prevent... When the threaded pressure ring (8) is tightened, the gas generator (4) is driven to rotate; the wrench clamps the outer eight sides (10.3), and the threaded pressure ring (8) is tightened by the tightening tool (10), pressing the pressure surface (8.2) onto the rear end face of the sealing disc (4.3); the structure of the locking pressure ring (9) is the same as that of the threaded pressure ring (8), only the height is smaller; after tightening, the pressure surface (9.2) of the locking pressure ring (9) presses against the rear end face (8.3), forming a double nut anti-loosening structure.

9. A performance test method for a self-unlocking, self-buffering, rotary-locking multi-section drag-reducing rod as described in any one of claims 1-8, characterized in that, Including inflation deployment test and non-contact modal test, The inflation deployment test includes: the drag-reducing rod is fixed on the test bracket through the outer shell (1), and an inflation fixture is installed in the middle of the chassis (7) of the drag-reducing rod. The structure of the inflation fixture is the same as that of the gas generator (4) and the self-unlocking component (5). No gunpowder is installed inside the inflation fixture. The inflation fixture is connected to the gas source through the inflation passage. A switch F1 and a pressure measuring device are connected in sequence along the airflow direction on the inflation passage. An air release passage is connected between the switch F1 and the pressure measuring device on the inflation passage. A switch F2 is connected on the air release passage. Compressed air is then injected into the drag-reducing rod. When the drag-reducing rod begins to unlock, the pressure inside the drag-reducing rod is recorded by a pressure measuring device. After the drag-reducing rod begins to unfold, the pressure is not released, but compressed air or nitrogen is slowly continued to be introduced until the drag-reducing rod is fully unfolded. The pressure change process during the unfolding process and the pressure value inside the drag-reducing rod when it is fully unfolded are recorded. Compressed air or nitrogen is continued to be introduced until the pressure inside the drag-reducing device reaches the set pressure. The air supply passage and the air release passage are closed, and an airtightness test is performed on the drag-reducing device. During the airtightness test, the pressure change process inside the drag-reducing device is continuously recorded. The non-contact modal test includes: the drag-reducing rod in the unfolded state is installed and fixed on the test bracket through the shell (1), and air is injected into the rod through the inflation tool. First, the excitation device is used to sweep the frequency according to the random vibration process. At the same time, the vibration displacement process of the characteristic position of the drag-reducing rod is measured by the laser micrometer. The first-order frequency value f1 is determined according to the first frequency value of the drag-reducing rod that generates resonance. Then, the excitation device is used to excite the rod in a sinusoidal vibration mode on both sides of the narrow band f1 frequency. The vibration displacement process of the characteristic position of the drag-reducing rod is measured by the laser micrometer to determine the accurate value of f1.

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