High-corrosion-resistance connecting fastener

Abstract

The invention discloses a high-corrosion-resistance connecting fastener, and relates to the technical field of fasteners, the high-corrosion-resistance connecting fastener comprises a head module and a rod module, and the head module and the rod module can form active separation connection; the head module comprises a head base body and an inner taper hole formed in the head base body in the axial direction, and a left-hand internal thread is machined on the inner wall of the inner taper hole. The whole body realizes the unification of high-strength locking and rapid active separation through the cooperation design of conical surface interference fit and Lurbert tear; and the memory alloy is utilized to accurately trigger crushing, and the prestress is instantly released. The LC resonance piece and the pre-deformation alloy ring jointly form a state sensing system, and remote monitoring and on-site indication are achieved. Maintenance cost is reduced through modularized sacrificial parts, smooth screwing is guaranteed through variable-pitch threads, double protection is formed by a rare earth anti-corrosion layer and a sealing face, and corrosion resistance in the extreme environment is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of fastener technology, specifically to a highly corrosion-resistant fastener. Background Technology

[0002] Fasteners are indispensable basic connecting components in aerospace, shipbuilding, marine, and petrochemical industries, and their connection reliability is directly related to the safety of the overall structure. With the continuous development of special application scenarios such as deep-sea exploration, space docking, and extreme environment operations, higher requirements are placed on fasteners: they must maintain a reliable connection with ultra-high strength under harsh working conditions such as vibration and corrosion, and also achieve rapid and active separation in emergency situations.

[0003] Currently, conventional bolted connections rely on thread engagement and preload for locking, but they are prone to loosening under strong vibrations, and disassembly requires rotation to loosen them, making instantaneous separation impossible. While welded or glued connections offer high strength, they are permanent connections and cannot be actively separated. Although solutions using breakable pins or explosion bolts for rapid separation exist, these structures often sacrifice connection strength, failing to meet ultra-high strength load-bearing requirements. Furthermore, during long-term service, fasteners are prone to fatigue cracks at the thread root, which are difficult to detect once corrosive media infiltrate. Fastener failure typically occurs in vulnerable areas such as the threads, but traditional fasteners require complete replacement upon failure, resulting in significant material waste. Especially in harsh environments such as marine and chemical plants, the overall lifespan of fasteners is often limited by localized corrosion, making it impossible to replace vulnerable parts individually, leading to high maintenance costs. Summary of the Invention

[0004] The purpose of this invention is to provide a highly corrosion-resistant fastener to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a highly corrosion-resistant connecting fastener, comprising: The head module and the rod module are capable of forming an active detachable connection; The head module includes a head base and an inner conical hole opened axially inside the head base, the inner wall of which is machined with a left-hand internal thread. The rod module includes a rod base and an outer cone frustum disposed at the bottom end of the rod base. The outer wall of the outer cone frustum is machined with a double-ended thread that mates with a left-hand internal thread. The taper of the outer cone frustum matches the taper of the inner cone hole, and the two are locked in a radial prestressed manner through an interference fit of the cone surfaces. The bottom end face of the outer cone is provided with an axially extending blind mounting hole, and a load-bearing component is provided in the blind mounting hole. The carrier component includes: Rupert's Tears glass ball; A metal pressure head covers the outside of the head of the Rupert's Tears glass ball. The metal pressure head has a cup-shaped structure, and its inner cavity matches the shape of the head of the Rupert's Tears glass ball. A through hole is opened at the bottom for the tail of the Rupert's Tears glass ball to pass through. A flexible sleeve is installed inside the through hole to protect the tail of the Rupert's Tears glass ball.

[0006] Preferably, the outer edge of the metal bearing head extends radially outward to form an annular bearing surface, and the annular bearing surface protrudes from the top end face of the outer cone. The metal bearing head is fixedly connected to the top of the outer cone. The tail of the Rupert's Tear glass ball extends through the through hole into the installation blind hole; At least three shape memory alloy spools are provided between the inner wall of the mounting blind hole and the tail of the Rupert's Tear glass sphere. The shape memory alloy spools are evenly distributed around the circumference, and their axes are parallel to the axis of the rod base. One end of the shape memory alloy spool abuts against the bottom of the mounting blind hole, and the other end passes through the interior of the outer cone. A fastening spring clip is installed at the connection interface of the outer bottom end of the outer cone. The side end of the shape memory alloy spool is driven to connect with the fastening spring clip.

[0007] Preferably, the connection between the head module and the rod module is achieved by a secondary locking mechanism using a fastening spring clip; The top of the inner part of the rod base is provided with a replaceable sacrificial thread section, and the side end of the sacrificial thread section is connected to an embedded retaining spring, which is connected to the main rod of the rod base. The top of the rod base is also provided with a concealed inner cavity. The inner wall of the concealed inner cavity is formed by multi-layer deposition of low-temperature alloy co-infiltration. The LC resonant plate is composed of a planar spiral inductor and interdigitated capacitors connected in parallel, which are composed of different metal layers. The rod base is provided with a sacrificial nut, and the side end of the sacrificial threaded section is connected to an inner rotating nut. The outer thread of the inner rotating nut is connected to a screw joint. The screw joint, the inner rotating nut, the sacrificial nut and the sacrificial threaded section are coaxially arranged.

[0008] Preferably, a pre-deformation memory alloy thin ring is installed on the outer side of the rod base. The side end of the pre-deformation memory alloy thin ring is provided with an annular contact surface. The initial state of the pre-deformation memory alloy thin ring is a pre-compressed non-circular shape. When the pre-tightening force borne by the fastener reaches the design threshold, the axial elongation of the rod base squeezes the annular contact surface, causing the pre-deformation memory alloy thin ring to undergo a sudden shape change and return to a circular shape. The pre-tightening force state is judged by visually observing the shape change of the thin ring.

[0009] Preferably, a docking component is installed inside the rod base, and a locking component is slidably connected to the left and right end surfaces of the docking component. A docking groove is opened on the outside of the head base near the docking component, and a docking ring is installed inside the front end of the docking component. The docking ring and the docking groove are engaged and connected.

[0010] Preferably, the head base comprises: Standard spiral section; First spiral section; The pitch of the second spiral section decreases sequentially from that of the standard spiral section, the first spiral section, and the second spiral section.

[0011] Preferably, microgrooves are formed on the bearing surfaces of the standard spiral portion and the first spiral portion, and chip guide grooves are formed on the other side of the standard spiral portion and the first spiral portion.

[0012] Preferably, a mating platform is installed on the outside of the outer cone, and a threaded groove is opened at the center end of the mating platform to be threadedly connected to the sacrificial thread section.

[0013] Preferably, the outer front end of the outer cone is fitted with a sealing annular pressure-bearing surface, which is located inside the mating parts.

[0014] Preferably, all exposed surfaces of the head module and the rod module are covered with a low-temperature alloy co-infiltration anti-corrosion layer, wherein the anti-corrosion layer is doped with 0.1%-0.5% rare earth elements.

[0015] Compared with the prior art, the beneficial effects of the present invention are: In this invention, a unified approach of high-strength locking and rapid active separation is achieved through the synergistic design of the conical interference fit and the load-bearing components. The interference fit between the outer conical frustum and the inner conical hole generates significant radial prestress, forming the first layer of frictional locking. Meanwhile, the Rupert's Tear glass sphere, with its extremely high compressive strength at its head, provides stable axial support for the conical interference fit, enabling the fastener to withstand extreme loads. When separation is required, the shape memory alloy spool undergoes a thermal phase change, driving the lever to laterally contact the tail of the Rupert's Tear glass sphere, triggering its instantaneous shattering and releasing the prestress. This achieves rapid active separation without the need for rotational loosening, reducing the difficulty of quickly disassembling traditional fasteners in emergency situations. Simultaneously, the LC resonator enables remote, non-destructive monitoring of the health status of internal sacrificial components through resonant frequency drift. The pre-deformed shape memory alloy thin ring abruptly changes from non-circular to circular when the pre-tightening force is met, providing a visually identifiable on-site indication. Together, these elements constitute a comprehensive sensing system covering the installation and usage status of the fastener. The modular design of the sacrificial thread section and sacrificial nut allows for individual replacement of vulnerable parts, significantly reducing maintenance costs. The three-section variable pitch thread, combined with microgrooves and chip guide grooves, ensures smooth engagement and precise control of preload. A rare-earth-doped anti-corrosion layer and a sealing annular pressure-bearing surface provide dual protection, significantly enhancing corrosion resistance in harsh environments such as marine and chemical plants. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the main structure of a highly corrosion-resistant connecting fastener according to the present invention; Figure 2 This is a schematic diagram of the internal cross-sectional structure of the main body of a high corrosion-resistant connecting fastener according to the present invention; Figure 3 This is a schematic diagram of the separation structure of the main body in a highly corrosion-resistant connecting fastener according to the present invention; Figure 4 This invention relates to a highly corrosion-resistant connecting fastener. Figure 2 A magnified structural diagram at point A; Figure 5 This invention relates to a highly corrosion-resistant connecting fastener. Figure 2 A magnified structural diagram at point B; Figure 6 This invention relates to a highly corrosion-resistant connecting fastener. Figure 3 A magnified structural diagram at point C; Figure 7 This invention relates to a highly corrosion-resistant connecting fastener. Figure 3 A magnified structural diagram at point D.

[0017] In the diagram: 100, Head module; 101, Head base; 102, Connecting groove; 103, Standard helix; 104, Microgroove; 105, Chip guide groove; 106, First helix; 200, Rod module; 201, Rod base; 202, Engaging part; 203, Pre-deformed shape memory alloy thin ring; 204, Annular contact surface; 205, External cone; 206, Double-ended thread; 207, Left-hand internal thread; 208, Connecting part; 2 09. Screw-in joint; 210. Internal rotating nut; 211. Sealing annular bearing surface; 212. Threaded groove; 213. Butt joint; 214. Embedded snap ring; 215. LC resonator; 216. Sacrificial nut section; 217. Sacrificial threaded section; 300. Bearing assembly; 301. Metal bearing head; 302. Rupert's Tear glass ball; 303. Shape memory alloy spool; 304. Fastening spring clip; 305. Through hole; 306. Annular bearing surface. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Reference Figures 1-7As shown: A highly corrosion-resistant fastener includes a head module 100 and a rod module 200. The head module 100 and the rod module 200 can form an active separation connection. The head module 100 includes a head base 101 and an inner conical hole axially formed inside the head base 101. The inner wall of the inner conical hole is machined with a left-hand internal thread 207. The rod module 200 includes a rod base 201 and an outer conical truncated cone 205 disposed at the bottom end of the rod base 201. The outer wall of the outer conical truncated cone 205 is machined with a double-ended thread 206 that mates with the left-hand internal thread 207. The taper of the outer conical truncated cone 205 matches the taper of the inner conical hole. The two are radially prestressed and locked by an interference fit of the conical surfaces. The bottom end face of the outer conical truncated cone 205 is provided with an axially extending mounting blind hole, and a load-bearing component 300 is disposed in the mounting blind hole. Specifically, the outer conical truncated cone 205 of the rod module 200 is aligned with the inner conical hole of the head module 100. The outer wall of the outer cone 205 is machined with a double-ended thread 206, and the inner wall of the inner cone hole that mates with the double-ended thread 206 is machined with a single-ended left-hand internal thread 207. The multi-ended thread allows for a larger lead during initial screwing, resulting in faster and smoother engagement, while the left-hand design ensures a tendency to prevent loosening under vibration conditions. The inner wall of the inner cone hole is machined with a left-hand internal thread 207. This allows the double-ended thread 206 to smoothly engage with the left-hand internal thread 207 during the initial screwing stage. By rotating the rod base 201, the outer cone 205 gradually enters the inner cone hole. During this process, the conical surface of the outer cone 205 begins to contact the conical surface of the inner cone hole. Due to the precise matching of their tapers, contact pressure begins to be generated between the conical surfaces as the screwing depth increases. Continuing to apply tightening torque causes the outer cone 205 to wedge deeper into the inner cone hole. Due to the interference fit design of the conical surface, when wedged in, the head base 101 is forced to undergo a slight radial expansion, while the bottom end of the rod base 201, i.e., the outer cone 205, is subjected to radial compression. This conical interference fit generates a large and uniform radial prestress between the two, forming the first high-strength frictional locking. Simultaneously, the engagement of the double-ended thread 206 and the left-hand internal thread 207 not only serves a guiding function, but its unique thread profile, under the interference fit, also bears part of the axial load, further enhancing the reliability of the connection. At this point, the head module 100 and the rod module 200 have formed a preliminary and secure connection. Furthermore, color rings are provided on the head module 100 and rod module 200, ensuring that only specific series of head modules 100 and rod modules 200 can be fully screwed together, preventing mismatch.

[0020] Preferred, such as Figure 1 , Figure 5 and Figure 6As shown, the support assembly 300 includes: Rupert's Tear glass ball 302; and a metal pressure head 301, which covers the outside of the head of Rupert's Tear glass ball 302. The metal pressure head 301 has a cup-shaped structure, and its inner cavity matches the shape of the head of Rupert's Tear glass ball 302. A through hole 305 is provided at the bottom for the tail of Rupert's Tear glass ball 302 to pass through. A flexible sleeve is installed inside the through hole 305 to protect the tail of Rupert's Tear glass ball 302. The outer edge of the metal bearing head 301 extends radially outward to form an annular bearing surface 306, which protrudes from the top end face of the outer cone 205. The metal bearing head 301 is fixedly connected to the top end of the outer cone 205. The tail of the Rupert's Tears glass ball 302 passes through the through hole 305 and extends into the interior of the mounting blind hole. At least three shape memory alloy spools 303 are provided between the inner wall of the mounting blind hole and the tail of the Rupert's Tears glass ball 302. The shape memory alloy spools 303 are evenly distributed around the circumference, and their axes are parallel to the axis of the rod base 201. One end of the shape memory alloy spool 303 abuts against the bottom of the mounting blind hole, and the other end passes through the interior of the outer cone 205. A fastening spring clip 304 is installed at the connection interface of the outer bottom end of the outer cone 205. The side end of the shape memory alloy spool 303 and the fastening spring clip 304 are drivenly connected. The connection between the head module 100 and the rod module 200 is achieved by secondary locking through the fastening spring clip 304.

[0021] Specifically, during the tightening process, as the outer cone 205 moves into the head base 101, the bearing assembly 300 begins to function. The bearing assembly 300 is located within a blind mounting hole at the bottom of the outer cone 205, and its metal bearing head 301 is fixedly connected to the top of the outer cone 205. The metal bearing head 301 has a cup-shaped structure, its inner cavity enclosing the head of the Rupert's Tears glass ball 302, and the shape of the inner cavity closely matches the head of the Rupert's Tears glass ball 302. A through hole 305 is provided at the bottom of the metal bearing head 301, through which the tail of the Rupert's Tears glass ball 302 extends into the blind mounting hole. A flexible sleeve, such as a Teflon sleeve, is installed inside the through hole 305 to protect the brittle tail of the Rupert's Tears glass ball 302 from stress concentration caused by direct metal contact. The outer edge of the metal bearing head 301 extends radially outward to form an annular bearing surface 306, which protrudes from the top end face of the outer cone 205. As the tightening force continues to increase, the annular bearing surface 306 first contacts the bearing surface inside the head base 101, or the opposing mounting surface, transmitting enormous axial pressure to the metal bearing head 301. The metal bearing head 301 then applies the pressure evenly to the head of the Rupert's Tears glass sphere 302. Due to the unique internal stress distribution characteristics of the Rupert's Tears glass sphere 302, the head of the Rupert's Tears glass sphere 302 in the prior art possesses extremely high compressive strength, enabling the Rupert's Tears glass sphere 302 to withstand enormous preload without breaking, thereby stably transmitting pressure to its tail region.

[0022] Meanwhile, at least three shape memory alloy spools 303 are evenly distributed circumferentially around the tail of the Rupert's Tears glass ball 302 within the mounting blind hole, and the shape memory alloy spools 303 are parallel to the axis of the rod base 201. One end of the shape memory alloy spool 303 abuts against the bottom of the mounting blind hole, and the other end passes through the interior of the outer cone 205, extending to the connection interface at the bottom of the outer cone 205, and is driven to connect with the fastening spring clip 304 located there. During tightening, as the pressure on the tail of the Rupert's Tears glass ball 302 increases, the shape memory alloy spool 303 is compressed or held in its initial position. When the tightening torque reaches the designed preload threshold, the relative position of the outer cone 205 and the head base 101 is precisely fixed. At this time, the shape memory alloy spool 303 reaches the phase change trigger point due to the stress it bears, or undergoes directional deformation, such as elongation or shortening, due to external temperature excitation, thereby driving the fastening spring clip 304 connected to its side end to move. The fastening spring clip 304 then pops out and engages with a pre-set slot or groove at the bottom of the head base 101, forming a second locking. This process requires no manual intervention, achieving automatic triggering of the second locking after the first locking, which greatly enhances the connection reliability of the fastener under extreme vibration and impact environments.

[0023] Preferred, such as Figures 1-4 and Figure 7 As shown, a replaceable sacrificial threaded section 217 is installed at the top of the inner part of the rod base 201. An embedded snap ring 214 is connected to the side end of the sacrificial threaded section 217, and the embedded snap ring 214 is connected to the main rod body of the rod base 201. A concealed inner cavity is also provided inside the top of the rod base 201. The inner wall of the concealed inner cavity is formed by multi-layer deposition of low-temperature alloy co-infiltration to form an LC resonant plate 215. The LC resonant plate 215 is composed of a planar spiral inductor and an interdigital capacitor connected in parallel, which are composed of different metal layers. A sacrificial nut part 216 is installed inside the rod base 201. An inner rotating nut 210 is connected to the side end of the sacrificial threaded section 217. A screw connection part 209 is connected to the external thread of the inner rotating nut 210. The screw connection part 209, the inner rotating nut 210, the sacrificial nut part 216 and the sacrificial threaded section 217 are arranged coaxially. A pre-deformation memory alloy thin ring 203 is installed on the outer side of the rod base 201. An annular contact surface 204 is installed on the side of the pre-deformation memory alloy thin ring 203. The initial state of the pre-deformation memory alloy thin ring 203 is a pre-compressed non-circular shape. When the preload of the fastener reaches the design threshold, the axial elongation of the rod base 201 compresses the annular contact surface 204, causing the pre-deformation memory alloy thin ring 203 to undergo a sudden shape change and return to a circular shape. The preload state is judged by visually observing the shape change of the thin ring. A mating platform 213 is installed on the outer side of the outer cone 205. A threaded groove 212 is opened at the center end of the mating platform 213, which is threaded to the sacrificial thread section 217. A sealing annular bearing surface 211 is sleeved on the outer front end of the outer cone 205. The sealing annular bearing surface 211 is located inside the mating part 208. The mating part 208 is installed inside the rod base 201. Engaging parts 202 are slidably connected to the left and right end surfaces of the mating part 208.

[0024] Specifically, a sacrificial thread section 217 is installed at the top of the inner part of the rod base 201. This section serves as the main load-bearing thread and is designed as a replaceable wear part. An embedded snap ring 214 is connected to the side end of the sacrificial thread section 217, achieving an elastic engagement with the main rod body of the rod base 201 through the embedded snap ring 214, ensuring axial positioning and facilitating subsequent disassembly. Simultaneously, a sacrificial nut section 216 is installed inside the rod base 201. An internal rotating nut 210 is connected to the side end of the sacrificial thread section 217, and a screw-in portion 209 is connected to the external thread of the internal rotating nut 210. Operators must ensure that the screw-in portion 209, the internal rotating nut 210, the sacrificial nut section 216, and the sacrificial thread section 217 are strictly coaxial to ensure uniform load distribution. The outer cone 205 is provided with a mating platform 213. The operator screws the end of the sacrificial thread section 217 into the threaded groove 212 opened at the center end of the mating platform 213, thereby connecting the entire load-bearing structure inside the rod base 201 with the outer cone 205 as one unit.

[0025] Next, a concealed inner cavity is provided inside the top of the rod base 201. The inner wall of this cavity is formed with an LC resonant plate 215 using a low-temperature alloy co-diffusion multilayer deposition process. This LC resonant plate 215 is composed of a planar spiral inductor and interdigital capacitor connected in parallel, formed by different metal layers, creating a passive resonant circuit. This process is completed before leaving the factory, making it an intelligent sensor embedded inside the rod base 201. Simultaneously, on the outer side of the rod base 201, the operator installs a pre-deformed shape memory alloy thin ring 203, initially pre-compressed into a non-circular shape, such as an ellipse, with its side end adjacent to the annular contact surface 204, preparing for subsequent visual monitoring of the pre-tightening force. The outer front end of the outer cone 205 is also fitted with a sealing annular bearing surface 211 for subsequent sealing with the mating part 208.

[0026] Next, the assembled rod module 200 is passed through the connected component, aligning its outer cone 205 with the inner cone hole of the head module 100. By rotating the rod base 201, the double-ended thread 206 engages with the left-hand internal thread 207, and is gradually tightened. As the tightening torque increases, the outer cone 205 and the inner cone hole form a conical interference fit, generating radial prestress locking.

[0027] During this process, when the preload on the fastener reaches the design threshold, the rod base 201 will undergo a slight axial elongation under the main load. This minute elongation is transmitted through the annular contact surface 204, compressing the adjacent pre-deformed shape memory alloy thin ring 203. When the stress reaches the phase transformation trigger point of the shape memory alloy, the thin ring undergoes an instantaneous shape change, rapidly returning to its original circular state from a pre-compressed non-circular shape, such as an ellipse. Operators or subsequent maintenance personnel only need to visually observe the shape change of the thin ring on the outer side of the rod base 201, from non-circular to circular, to intuitively and quickly determine whether the preload has met the standard, without relying on complex equipment such as torque wrenches or ultrasonic testing. This greatly simplifies the on-site installation quality control process, especially in situations where space is limited or instruments are inconvenient to use.

[0028] During the service life of the fastener, the condition of its internal structure can be continuously monitored non-contactly. The LC resonator 215 inside the top of the rod base 201 acts as a passive sensor, its resonant frequency determined by its geometry and material properties. When external detection equipment, such as a handheld sweep frequency meter, approaches the fastener and emits a scanning signal of a specific frequency, the LC resonator 215 resonates at its natural frequency and reflects the characteristic signal back through the antenna effect. When the internal structure of the rod, such as the sacrificial thread section 217 and the sacrificial nut section 216, develops microcracks, deformation, or material loss due to long-term load, corrosion, or fatigue, these changes are transmitted to the walls of the concealed internal cavity, causing minute strain or stress changes in the substrate of the LC resonator 215, which in turn leads to a change in its equivalent inductance or capacitance. This change in equivalent inductance or capacitance is reflected in the drift of the resonant frequency. Maintenance personnel can indirectly determine the health status of key components inside the rod base 201 by periodically detecting and comparing changes in the resonant frequency, achieving remote, non-destructive monitoring of internal damage to the fastener. This avoids the drawbacks of traditional methods that require disassembly and inspection, and significantly improves the intelligence and efficiency of equipment maintenance.

[0029] When an anomaly is detected by the LC resonator 215, or when maintenance is required according to the preset service cycle, the operator can easily replace the vulnerable parts inside the rod module 200. Since the surface of the fastener's end is easily corroded during use, to address this issue, the fastener is first removed from the equipment as a whole. Then, by using a tool to release the engagement of the embedded retaining ring 214, the sacrificial threaded section 217 can be pulled out from the top of the rod base 201. Since the side end of the sacrificial threaded section 217 is connected to the inner rotating nut 210, which is threadedly connected to the screw-on part 209, it can be further rotated and disassembled to separate the sacrificial threaded section 217, the inner rotating nut 210, the sacrificial nut part 216, and other components one by one. The screw-on part 209, the inner rotating nut 210, the sacrificial nut part 216, and the sacrificial threaded section 217 are designed as individually replaceable sacrificial parts. When they reach their service life limit, only the corresponding new parts need to be replaced, without discarding the entire rod base 201. During reassembly, the new sacrificial threaded section 217 is connected to the screw joint 209 via the inner rotating nut 210 in reverse order, and then re-engaged into the main rod body of the rod base 201 via the embedded snap ring 214. Finally, the end of the sacrificial threaded section 217 is screwed into the threaded groove 212 of the mating platform 213. This modular and replaceable design greatly reduces long-term operating costs and minimizes resource waste.

[0030] During the fastener installation process on the mating member 208, the mating member 208 installed inside the rod base 201 and the locking members 202 slidably connected to its left and right end surfaces cooperate with the head base 101. When the rod module 200 is screwed into the head module 100 to the predetermined position, the mating ring at the front end of the mating member 208 engages with the mating groove 102 on the outside of the head base 101, providing additional connection stability. At the same time, the sealing annular bearing surface 211 sleeved on the outer front end of the outer cone 205 fits tightly against the inner surface of the mating member 208 after connection, forming an effective radial seal to prevent moisture, dust, and corrosive media from intruding into the connection interface. Together with the low-temperature alloy co-permeable anti-corrosion layer covering all exposed surfaces, this constitutes double protection, ensuring the long-term reliable service of the fastener in harsh environments such as marine and chemical industries.

[0031] Preferred, such as Figures 1-3 , Figure 5 , Figure 6 As shown, a docking groove 102 is formed on the outer side of the head base 101 near the docking member 208. A docking ring is installed inside the front end of the docking member 208, and the docking ring and the docking groove 102 engage and connect. The head base 101 includes: a standard spiral part 103; a first spiral part 106; and a second spiral part, with the spiral pitch of the standard spiral part 103, the first spiral part 106, and the second spiral part decreasing sequentially. Microgrooves 104 are formed on the bearing surfaces of the standard spiral part 103 and the first spiral part 106, and chip guide grooves 105 are formed on the other side of the standard spiral part 103 and the first spiral part 106. All exposed surfaces of the head module 100 and the rod module 200 are covered with a low-temperature alloy co-diffusion anti-corrosion layer, which is doped with 0.1%-0.5% rare earth elements.

[0032] The threaded portion of the head base 101 adopts a three-stage variable pitch design, including a standard helical section 103, a first helical section 106, and a second helical section. The pitch of the standard helical section 103, the first helical section 106, and the second helical section decreases sequentially, with the standard helical section 103 having the largest pitch, facilitating initial quick alignment and insertion. As the screw depth increases, the pitch gradually becomes denser, allowing the first helical section 106 and the second helical section to more precisely adjust the preload and effectively disperse stress concentration in the load-bearing area. Microgrooves 104 are formed on the load-bearing surfaces of the standard helical section 103 and the first helical section 106. These microgrooves 104 can store a small amount of lubricant during tightening, reducing the coefficient of friction and ensuring precise control of the preload. Simultaneously, a chip guide groove 105 is formed on the other side of the standard helical section 103 and the first helical section 106, i.e., the non-load-bearing surface. The chip guide groove 105 can accommodate and remove any small debris or contaminants that may be present during thread engagement, preventing thread jamming and ensuring smooth connection.

[0033] Next, the rod module 200 is passed through the connecting member below, aligning its outer cone 205 with the inner cone hole of the head module 100. Simultaneously, a docking member 208 is pre-installed on the head base 101 near the docking member 208. Engaging members 202 are slidably connected to the left and right ends of the docking member 208, and a docking ring is installed inside its front end. As the rod module 200 begins to screw into the head module 100, the operator pushes or guides the docking member 208, causing its front docking ring to gradually approach the docking groove 102 outside the head base 101. When the rod module 200 is screwed into the predetermined initial position, the docking ring at the front end of the docking member 208, guided and restrained by the engaging members 202, accurately engages into the docking groove 102 of the head base 101, forming the first auxiliary connection. This locking and engaging mechanism not only provides guidance and pre-positioning for subsequent main connections, but also prevents relative rotation or displacement between the head module 100 and the rod module 200 before they are fully locked in a vibrating environment, thus improving the stability and safety of the installation process.

[0034] More specifically, the operator then continues to apply tightening torque, causing the outer cone 205 of the rod module 200 to wedge deeper into the inner cone hole of the head module 100. Due to the precise match between the taper of the outer cone 205 and the inner cone hole, the interference fit of the cone surface generates significant radial prestress, forming the first high-strength frictional locking. Simultaneously, the engagement of the double-ended thread 206 and the left-hand internal thread 207 further enhances the reliability of the connection. When the tightening force reaches a preset threshold, the load-bearing component 300, installed in the blind hole at the bottom of the outer cone 205, begins to function. The annular bearing surface 306 of the metal bearing head 301 contacts the internal bearing surface of the head base 101, transferring pressure to the head of the Rupert's Tears glass sphere 302. Due to the extremely high compressive strength of the head of the Rupert's Tears glass sphere 302, it can stably bear the load without breaking, transferring the pressure to the tail. At this point, the shape memory alloy spool 303 surrounding the tail of the glass sphere deforms due to stress reaching the phase transition point or through temperature excitation, driving the connected fastening spring clip 304 to automatically pop out and engage in the pre-set groove at the bottom of the head base 101, forming a second locking. Thus, the fastener completes the dual locking of conical prestressed locking and locking against loosening.

[0035] In specific situations requiring rapid separation, such as space docking or underwater emergency release, when the temperature of the shape memory alloy spool 303 is raised through external heating, it undergoes a phase change and produces directional contraction or elongation. This first drives the fastening spring clip 304 to retract, releasing the secondary locking mechanism. Simultaneously, the movement of the shape memory alloy spool 303 directly acts on the tail of the Rupert's Tears glass sphere 302, triggering its instantaneous and controllable shattering. After the glass sphere breaks, the enormous pressure it bears is released instantly. Specifically, a tiny lever is provided at one end of the shape memory alloy spool 303 near the tail of the Rupert's Tears glass sphere 302. The shape memory alloy spool 303 is made of TiNi alloy, and the lever maintains a tiny gap with the tail of the Rupert's Tears glass sphere 302 in the initial state. During separation, the shape memory alloy spool 303 undergoes torsion or bending deformation due to heat. The heating is achieved by localized and precise heating of the shape memory alloy spool 303 area through an external heat source, such as a heating plate or laser, causing the shape memory alloy spool 303 to undergo a phase change and instantly lengthen or shorten. The shape memory alloy spool 303 drives the lever to swing, thereby touching the tail of the Rupert's Tear glass ball 302 laterally and triggering its breakage. The metal pressure head 301 loses its support, and the pressure of the cone-shaped interference fit between the head module 100 and the rod module 200 disappears. The two modules can be easily separated under minimal external force, achieving rapid active separation without the need for rotation or loosening.

[0036] All exposed surfaces of the head module 100 and the rod module 200 are covered with a low-temperature alloy co-diffusion anti-corrosion layer, which uniformly dops with 0.1%-0.5% rare earth elements, such as lanthanum and cerium. The addition of rare earth elements refines the grain size of the infiltrated layer, improves its density, and significantly enhances the corrosion resistance of the anti-corrosion layer in harsh environments such as marine climates and chemical media. In addition, the sealing annular bearing surface 211 fitted on the outer front end of the outer cone 205 fits tightly against the inner surface of the mating part 208 after connection, forming an effective radial seal to prevent moisture, dust, and corrosive media from intruding into the connection interface, thus forming a double protection together with the surface anti-corrosion layer.

[0037] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly corrosion-resistant connecting fastener, characterized in that, include: The head module (100) and the rod module (200) are capable of forming an active detachable connection; The head module (100) includes a head base (101) and an inner conical hole opened axially inside the head base (101), the inner wall of which is machined with a left-hand internal thread (207). The rod module (200) includes a rod base (201) and an outer cone (205) disposed at the bottom end of the rod base (201). The outer wall of the outer cone (205) is machined with a double-ended thread (206) that mates with the left-hand internal thread (207). The taper of the outer cone (205) matches the taper of the inner cone hole, and the two are radially prestressed and locked by an interference fit of the cone surfaces. The bottom end face of the outer cone (205) is provided with an axially extending blind hole, and a load-bearing component (300) is provided in the blind hole. The carrier component (300) includes: Rupert's Tear glass ball (302), the head of which is used to bear and transmit the axial preload force generated by the interference fit of the conical surface; The shape memory alloy spool (303) is used to break the Rupert's Tear glass ball (302) after receiving an external trigger signal, thereby releasing the axial preload, releasing the radial prestress lock, and realizing the active separation of the head module (100) and the rod module (200).

2. The high corrosion-resistant fastener according to claim 1, characterized in that: The carrier component (300) further includes: A metal pressure head (301) covers the outside of the head of the Rupert's Tear glass ball (302). The metal pressure head (301) has a cup-shaped structure, and its inner cavity matches the shape of the head of the Rupert's Tear glass ball (302). A through hole (305) is provided at the bottom for the tail of the Rupert's Tear glass ball (302) to pass through. A flexible sleeve is installed inside the through hole (305) to protect the tail of the Rupert's Tear glass ball (302). The outer edge of the metal bearing head (301) extends radially outward to form an annular bearing surface (306), which protrudes from the top end face of the outer cone (205). The metal bearing head (301) is fixedly connected to the top of the outer cone (205); The tail of the Rupert's Tear glass ball (302) extends through the through hole (305) into the installation blind hole; Three memory alloy spools (303) are disposed between the inner wall of the mounting blind hole and the tail of the Rupert's Tear glass ball (302). The memory alloy spools (303) are evenly distributed around the circumference, and their axis is parallel to the axis of the rod base (201). One end of the memory alloy spool (303) abuts against the bottom of the mounting blind hole, and the other end passes through the interior of the outer cone (205). A fastening spring clip (304) is installed at the connection interface of the outer bottom end of the outer cone (205). The side end of the memory alloy spool (303) and the fastening spring clip (304) are drivenly connected.

3. The high corrosion-resistant fastener according to claim 1, characterized in that: The connection between the head module (100) and the rod module (200) is achieved by secondary locking through the fastening spring clip (304); The top of the inner part of the rod base (201) is provided with a replaceable sacrificial thread section (217), and the side end of the sacrificial thread section (217) is connected to an embedded snap ring (214), which is connected to the main rod of the rod base (201). The top of the rod base (201) is also provided with a concealed inner cavity. The inner wall of the concealed inner cavity is formed by low temperature alloy co-infiltration multilayer deposition to form an LC resonant plate (215). The LC resonant plate (215) is composed of a planar spiral inductor and interdigitated capacitor connected in parallel, which are composed of different metal layers. The rod base (201) is provided with a sacrificial nut (216) inside, and the side end of the sacrificial threaded section (217) is connected to an inner rotating nut (210). The outer thread of the inner rotating nut (210) is connected to a screw joint (209). The screw joint (209), the inner rotating nut (210), the sacrificial nut (216) and the sacrificial threaded section (217) are coaxially arranged.

4. The high corrosion-resistant fastener according to claim 1, characterized in that: A pre-deformation memory alloy thin ring (203) is installed on the outer side of the rod base (201), and an annular contact surface (204) is installed on the side of the pre-deformation memory alloy thin ring (203). The initial state of the pre-deformation memory alloy thin ring (203) is a pre-compressed non-circular shape.

5. The high corrosion-resistant fastener according to claim 1, characterized in that: The rod base (201) is provided with a docking part (208) inside. The left and right ends of the docking part (208) are slidably connected with a locking part (202). The head base (101) is provided with a docking groove (102) on the outside near the docking part (208). The front end of the docking part (208) is provided with a docking ring. The docking ring and the docking groove (102) are engaged and connected.

6. The high corrosion-resistant fastener according to claim 1, characterized in that: The head base (101) includes: Standard spiral section (103); First spiral section (106); The pitch of the second spiral section decreases sequentially from that of the standard spiral section (103), the first spiral section (106), and the second spiral section.

7. The high corrosion-resistant fastener according to claim 6, characterized in that: Microgrooves (104) are provided on the bearing surfaces of the standard spiral part (103) and the first spiral part (106), and chip guide grooves (105) are provided on the other side of the standard spiral part (103) and the first spiral part (106).

8. The high corrosion-resistant fastener according to claim 1, characterized in that: The outer cone (205) is provided with a docking platform (213) on its outside, and the center end of the docking platform (213) is provided with a threaded groove (212) that is threadedly connected to the sacrificial threaded section (217).

9. The high corrosion-resistant fastener according to claim 1, characterized in that: The outer front end of the outer cone (205) is fitted with a sealing annular pressure bearing surface (211), which is located inside the docking part (208).

10. The high corrosion-resistant fastener according to claim 1, characterized in that: All exposed surfaces of the head module (100) and the rod module (200) are covered with a low-temperature alloy co-infiltration anti-corrosion layer, which is doped with 0.1%-0.5% rare earth elements.

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