A pre-tightening force enhanced spin-riveting blind bolt

Abstract

The application provides a pre-tightening force enhanced spin-riveting blind bolt, which comprises a core rod, a driving body, an expansion ring, a forming sleeve, a nail body, a lock ring and a spin-pressing bushing which are sleeved on the core rod; wherein the core rod is an elongated rod structure, the end of the core rod is connected with a riveting gun chuck, the middle part of the core rod is provided with a diameter breaking groove, and the first end of the core rod is provided with an end head; the driving body, the forming sleeve and the nail body are in an integrated tubular structure, the forming sleeve forms a flexible deformation area, and the inside of the forming sleeve is provided with a containing cavity for containing the expansion ring, the driving body is connected with the first end of the core rod; the spin-pressing bushing is a rotary body structure with a stepped hole in the inside, the lock ring is arranged in the stepped hole and is in meshing connection with the end face of the stepped hole of the spin-pressing bushing, and the outer ring of the spin-pressing bushing is provided with a shearing groove. The application realizes the combined movement mode of pulling and rotating of the core rod, can improve the pre-tightening force of the product by more than 50%, and can better meet the connection requirements of high clamping force connection parts.

Description

Technical Field

[0001] The present application belongs to the technical field of fasteners, and in particular relates to a pre-tightening force enhanced type blind rivet bolt. Background Art

[0002] The design process for high-end equipment, such as aerospace equipment, typically prioritizes compact structures due to size and weight. These compact components require relatively limited space for connection and installation. Conventional fasteners like bolts and nuts, which require double-sided installation, are not suitable for these installation requirements. Therefore, riveting is often used in these tight installation spaces where double-sided operation is inconvenient. Blind rivets are commonly used for structural connections. These rivets offer advantages such as light weight, reliable connections, high strength, and quick and easy installation, making them widely used in various aerospace applications.

[0003] Currently used blind rivets are primarily pull-and-screw types. These rivets are secured by a single action of a rivet gun, which pulls or rotates a core rod, causing the rivet sleeve to deform. Existing blind rivets have a narrow range of applications for interlayers, requiring a wider range of specifications to meet the riveting requirements of interlayers of varying thicknesses. Furthermore, the flushness of the rivet fractures is often uneven, with a significant portion of the core rod protruding from the rivet body surface. This requires secondary grinding to meet the high flushness requirements of the exterior surfaces of stealth aircraft.

[0004] For general mechanical connection occasions, existing blind rivets can basically meet the assembly requirements of products. However, in some special occasions, such as those with high requirements for preload force and riveted fracture flushness, existing blind rivets are difficult to meet the above connection requirements. Summary of the Invention

[0005] In view of this, the present application aims to propose a preload-enhanced rotary rivet blind bolt to solve the above technical problems.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0007] The present application provides a preload-enhanced spin-riveted blind bolt, comprising a core rod, and a driving body, an expansion ring, a forming sleeve, a nail body, a locking ring, and a spinning bushing sleeve sleeved on the core rod;

[0008] The core rod is a slender rod structure, the end of the core rod is connected to the rivet gun chuck, the middle of the core rod is provided with a cutting groove, and the head end of the core rod is provided with a terminal;

[0009] The driving body, the forming sleeve and the nail body are in a tubular structure, the forming sleeve forms a flexible deformation region, and an accommodation cavity for accommodating the expansion ring is arranged in the forming sleeve, and the driving body is connected with the first end of the core rod;

[0010] The spinning bush is a rotary body structure with a stepped hole in the inside, and the locking ring is arranged in the stepped hole and is in meshing connection with the end face of the stepped hole of the spinning bush, and the outer ring of the spinning bush is provided with a shearing groove.

[0011] Further, the end of the core rod is a flat structure and is matched with a flat slot arranged in the rivet gun chuck, a straight ring groove is arranged on the core rod, and the core rod is clamped and fixed by the rivet gun chuck;

[0012] The inner wall of the end of the core rod is provided with a cross-shaped anti-rotation tooth, and a cross-shaped anti-rotation groove matched with the cross-shaped anti-rotation tooth is arranged on the end face of the driving body, so that the driving body is correspondingly connected with the core rod.

[0013] Further, the side of the middle part of the core rod close to the straight ring groove is provided with a clamping ring groove for interference fit with the inner hole of the spinning bush to clamp the spinning bush.

[0014] Further, the forming sleeve is a hollow tubular structure with a rotary groove in the inside, and the thickness of the rotary groove close to the nail body is greater than the thickness of the rotary groove close to the driving body, so as to form an accommodation cavity.

[0015] Further, the expansion ring is a circular ring rotary structure, the cross-sectional shape of the circular ring is matched with the shape of the rotary groove, and an inclined groove is arranged in the middle of the circular ring.

[0016] Further, the nail body is a hollow rotary structure with a stepped hole in the inside, and a locking hole communicated with the stepped hole is further arranged in the inside of the nail body, wherein the stepped hole is matched with the blocking step arranged in the middle part of the core rod;

[0017] A spiral locking groove in a tapered structure is arranged between the diameter breaking groove and the blocking step, the locking groove and the locking hole form a wedge-shaped space, and the driving end of the spinning bush pushes the locking ring, so that the locking ring is extruded into the wedge-shaped space along the locking groove.

[0018] Further, the end face of the spinning bush close to the head of the rivet gun is a conical face, the conical face has an angle range of 150 degrees to 160 degrees, and a first meshing tooth is arranged on the conical face, and the first meshing tooth is in meshing connection with the end face of the head of the rivet gun.

[0019] Further, a second meshing tooth is arranged on the end face of the stepped hole arranged in the spinning bush, and a third meshing tooth in meshing connection with the second meshing tooth is arranged on the side end face of the locking ring.

[0020] Further, the lock ring is a thin-walled circular ring structure, and the metal matrix hardness at one end of the third meshing tooth is greater than the metal matrix hardness at the other end of the lock ring.

[0021] Further, the outer surface of the lock ring is also coated with a lubricating coating.

[0022] Compared with the prior art, the pre-tightening force enhanced spin-lap rivet blind bolt has the following beneficial effects:

[0023] The pre-tightening force enhanced spin-lap rivet blind bolt has the following beneficial effects: BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments thereof and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0025] Figure 1 A pre-tightening force enhanced spin-lap rivet blind bolt installation structure according to an embodiment of the present application is shown in the figure;

[0026] Figure 2 A core rod structure according to an embodiment of the present application is shown in the figure;

[0027] Figure 3 A rivet body, a forming sleeve, an expansion ring, and a driving body structure according to an embodiment of the present application are shown in the figure;

[0028] Figure 4 A spin-pressing bushing structure according to an embodiment of the present application is shown in the figure;

[0029] Figure 5 A lock ring structure according to an embodiment of the present application is shown in the figure;

[0030] Figure 6 A spin-pressing bushing and a lock ring structure according to an embodiment of the present application are shown in the figure;

[0031] Figure 7 A spin-pressing bushing and a lock ring structure according to an embodiment of the present application are shown in the figure;

[0032] Figure 8 The device is installed, and an effect diagram is shown in the figure.

[0033] REFERENCE SIGNS

[0034] 1-core rod; 11-straight ring groove; 12-clasping ring groove; 13-diameter breaking groove; 14-locking groove; 15-blocking step; 16-end head; 17-cross-shaped anti-rotation tooth; 2-driving body; 21-cross-shaped anti-rotation groove; 3-expanding ring; 31-inclined groove; 4-molding sleeve; 41-rotary groove; 5-nail body; 51-locking hole; 52-step hole; 6-spinning bushing; 61-first engaging tooth; 62-second engaging tooth; 63-cutting groove; 7-locking ring; 71-third engaging tooth. DETAILED DESCRIPTION

[0035] For the purpose, technical solutions and advantages of the present application to be more clearly understood, the present application is further described in detail below with reference to specific embodiments and with reference to the accompanying drawings.

[0036] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as the general meaning understood by those skilled in the art to which the embodiments of the present application belong. The terms "first", "second" and the like used in the embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "include" or "contain" and the like mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and the like are not limited to physical or mechanical connections, but can be logical or electrical connections, which include electrical connections, whether direct or indirect. The terms "up", "down", "left", "right" and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships may

[0037] also change accordingly.

[0038] Referring to Figure 1 Fig. 1, the embodiments provide a pre-tightening force enhanced spin-lay rivet blind bolt, which comprises a core rod 1, and a driving body 2, an expanding ring 3, a molding sleeve 4, a nail body 5, a locking ring 7 and a spinning bushing 6 which are sleeved on the core rod 1;

[0039] The core rod 1 is an elongated rod structure, the end of the core rod 1 is connected with a rivet gun chuck, the middle part of the core rod 1 is provided with a diameter breaking groove 13, and the first end of the core rod 1 is provided with an end head 16.

[0040] The driving body 2, the molding sleeve 4 and the nail body 5 are in tubular structure and are integrally arranged, the molding sleeve 4 forms a flexible deformation area, and an accommodating cavity for accommodating the expanding ring 3 is arranged in the interior of the molding sleeve 4, and the driving body 2 is connected with the first end of the core rod 1.

[0041] The spinning bush 6 is a rotary body structure with a stepped hole 52 inside, and the lock ring 7 is arranged in the stepped hole 52 and is engaged with the end face of the stepped hole 52 of the spinning bush 6, and the outer ring of the spinning bush 6 is provided with a shearing groove 63.

[0042] The pre-tightening force enhanced spinning pull rivet blind bolt has the characteristics of simple structure, convenient installation and inspection, wide range of use of the interlayer, large pre-tightening force and good riveting flatness, and through the setting of the rotation engaging tooth driving structure and the locking groove 14 locking performance enhanced tapered spiral line structure, the core rod 1 is driven to realize the combined motion mode of pulling and rotating, so that the lock ring 7 more tightly locks the core rod 1 locking groove 14, the pre-tightening force of the product can be improved by more than 50%, and the connection demand of the high clamping force connection part can be better met.

[0043] In some embodiments, the end of the core rod 1 is a flat structure and cooperates with the flat groove arranged in the rivet gun chuck, the core rod 1 is provided with a straight ring groove 11 and is clamped and fixed by the rivet gun chuck;

[0044] The inner wall of the end head 16 of the core rod 1 is provided with a cross-shaped anti-rotation tooth 17, and the end face of the driving body 2 is provided with a cross-shaped anti-rotation groove 21 matched with the cross-shaped anti-rotation tooth 17, so that the driving body 2 is correspondingly clamped with the core rod 1.

[0045] The side of the middle part of the core rod 1 close to the straight ring groove 11 is provided with a clamping ring groove 12 for interference fit with the inner hole of the spinning bush 6 to clamp the spinning bush 6.

[0046] Specifically, in the embodiment, as shown in Figure 2 The core rod 1 is an elongated rod structure, which is provided with a straight ring groove 11, an anti-rotation flat structure, a clamping ring groove 12, a neck breaking groove, a spiral line type locking groove 14, a blocking step 15 and a cross-shaped anti-rotation tooth 17.

[0047] The purpose of the straight ring groove 11 is to increase the friction between the core rod 1 and the rivet gun chuck. When the rivet gun works, the rivet gun chuck clamps the straight ring groove 11 part of the core rod 1 to pull the core rod 1 backward under the action of the air pressure piston, so that the rivet gun chuck does not slip when clamping the core rod 1.

[0048] The anti-rotation flat structure is matched with the flat groove in the rivet gun head. The anti-rotation flat structure is inserted into the flat groove in the gun head. Since the flat groove cannot rotate, it can prevent the core rod 1 from rotating.

[0049] The clamping ring groove 12 is matched with the inner hole of the spinning bush 6 to clamp the spinning bush 6, preventing the blind bolt from loosening during transportation, storage or handling.

[0050] The function of the neck breaking groove is to break at the neck breaking groove when the combined load of the pulling force and the breaking torque of the core rod 1 exceeds the strength of the core rod 1.

[0051] After the blind end bulge is formed, after the axial displacement of the core rod 1 is restricted by the two blocking steps 15, the rivet gun chuck clamps the core rod 1 and cannot move further backward. When the combined load of tension and torsional force on the tail of the core rod 1 exceeds the limit value that the breaking neck groove can withstand, it will break.

[0052] The cross-shaped anti-rotation tooth 17 cooperates with the cross-shaped anti-rotation groove 21 on the driving body 2 to limit the rotation of the nail body 5 and the core rod 1, thereby better transmitting the torque of the holster to the locking ring 7 and driving the locking ring 7 to rotate into the bottom of the locking groove 14.

[0053] In some embodiments, the forming sleeve 4 is a hollow tubular structure having a rotation groove 41 therein. The thickness of the rotation groove 41 near the nail body 5 is greater than the thickness of the end near the driving body 2 to form an accommodating cavity.

[0054] Specifically, in this embodiment, the nail body 5, the forming sleeve and the driving body 2 are as follows. Figure 3 As shown, the nail body 5 and the driving body 2 are made of the same high-strength titanium alloy material, which has high strength and hardness, similar to a rigid body, and will not deform during the riveting process; the forming sleeve is made of a softer pure titanium material with lower hardness, and is mainly used for bulging deformation during the riveting process; the three parts are finally welded into one part by metal high-speed friction welding, becoming a nail body 5 assembly with high strength at both ends and low strength in the middle.

[0055] Forming sleeve Figure 3 As shown, it is a hollow tubular part with a revolving groove 41 (accommodating chamber for the expansion ring 3) inside. The revolving groove 41 is thicker at the end close to the head of the nail body 5 and thinner at the side close to the driving body 2, which can more conveniently and evenly guide the fastener to bulge from the smallest interlayer to the largest interlayer range. The second function of the revolving groove 41 is to place the memory alloy expansion ring 3. The forming sleeve is made of softer pure titanium alloy material, and the whole is formed by upsetting and extrusion. Due to the presence of the groove, the strength of the middle part is lower, and it is used to bulge first during riveting. The length of the accommodating chamber for the expansion ring 3 is positively correlated with the applicable interlayer length of the fastener.

[0056] During the riveting process, under the extrusion of the forming sleeve by the nail body 5 and the driving body 2, the rotary groove 41 will gradually form a bulge at the blind end of the mounting plate, thereby achieving the purpose of clamping.

[0057] The driving body 2 is a circular ring-shaped part, which is made of the same high-strength titanium alloy material as the nail body 5. It is a rigid body and not easy to deform. A cross-shaped anti-rotation groove is provided on the right end face of the driving body 2, which cooperates with the cross-shaped anti-rotation teeth on the lower support surface of the core rod 1 to fix the driving body 2 and the core rod 1 to prevent rotation between the two.

[0058] In some embodiments, the expansion ring 3 is a circular rotating structure, the cross-sectional shape of which matches the shape of the rotating groove 41 , and an inclined groove 31 is provided in the middle of the ring.

[0059] Specifically, in this embodiment, the expansion ring 3 parts are as follows Figure 3 As shown, it is made of memory alloy material and is a circular rotating part. Its cross-sectional shape is the same as the groove shape in the forming sleeve. An inclined groove 31 is opened in the middle of the ring, so that the expansion ring 3 has a certain elasticity in the radial direction, which allows the expansion ring 3 to be easily installed in the expansion ring 3 accommodating cavity in the nail body 5 assembly.

[0060] In some embodiments, the nail body 5 is a hollow rotary structure with a stepped hole 52 formed therein. The nail body 5 further has a locking hole 51 formed therein that communicates with the stepped hole 52. The stepped hole 52 cooperates with the blocking step 15 provided in the middle of the core rod 1.

[0061] A spiral locking groove 14 with a conical structure is provided between the breaking groove 13 and the blocking step 15. The locking groove 14 cooperates with the locking hole 51 to form a wedge-shaped space. The driving end of the spinning bushing 6 pushes the locking ring 7 so that the locking ring 7 is squeezed into the wedge-shaped space along the locking groove 14.

[0062] Specifically, in this embodiment, the nail body 5 is a hollow rotating part with a stepped hole 52 inside. The nail body 5 is provided with a connected stepped hole 52 and a locking hole 51. The function of the blocking platform is to cooperate with the blocking step 15 of the core rod 1. During the riveting process, after the core rod 1 is pulled into position, the displacement will be restricted by the blocking platform. The locking hole 51 is used in conjunction with the locking groove 14 on the core rod 1. After the core rod 1 is pulled into position, a wedge-shaped space will be formed between the locking hole 51 of the nail body 5 and the locking groove 14 on the core rod 1, which facilitates the locking ring 7 to be squeezed in to achieve the locking purpose.

[0063] The locking groove 14 is used in conjunction with the locking hole 51 of the nail body 5. After the core rod 1 is pulled into position, a wedge-shaped space will be formed between the core rod 1 and the nail body 5. The locking ring 7 will be squeezed into the wedge-shaped space under the pushing action of the sheared spinning bushing 6, thereby achieving the purpose of locking. The locking groove 14 is also provided with a spiral tapered raised thread. When the spinning bushing 6 driving portion spins the locking ring 7, it will tighten the locking ring 7 along the tapered thread into the deeper part of the wedge-shaped locking space, thereby enhancing the preload force. Moreover, due to the mechanical locking effect of the tapered raised thread, the locking ring 7 will not elastically slip in the locking groove 14 at the moment the core rod 1 is twisted off, and there will be no loss of preload force.

[0064] In some embodiments, the end face of the spinning bushing 6 near the end of the rivet gun head is a conical face, the conical face has an angle ranging from 150 degrees to 160 degrees, and the conical face is provided with first engagement teeth 61 which are engaged with the end face of the rivet gun head.

[0065] The end face of the stepped hole provided in the spinning bushing 6 is provided with second engagement teeth 62, and one side end face of the lock ring 7 is provided with third engagement teeth 71 which are engaged with the second engagement teeth 62.

[0066] Specifically, in the present embodiment, the spinning bushing 6 is a rotary part with a stepped hole in the inside, as shown in Figure 4 and Figure 1 and Figure 6 .

[0067] During riveting, the spinning bushing 6 is first subjected to the extrusion action of the end face of the rivet gun head and the nail body 5, and when the extrusion force exceeds a certain limit, the spinning bushing 6 will break at the position of the shear groove 63 of the stepped hole, so as to push the lock ring 7 into the wedge-shaped locking space.

[0068] The left side end face of the spinning bushing 6 is a conical face, the conical face has an angle ranging from 150 degrees to 160 degrees, and the conical face is provided with engagement teeth, and when the product is installed, the end face of the spinning bushing 6 is matched with the end face of the rivet gun head, and the end face of the gun head is also provided with engagement teeth which are matched in number and contour, and when the gun sleeve rotates, the gun sleeve will drive the spinning bushing 6 to rotate synchronously through the engagement of the engagement teeth therebetween. The end face of the stepped hole 52 in the spinning bushing 6 is also provided with engagement teeth, after the spinning bushing 6 is sheared and the lock ring 7 is extruded into the locking groove 14, the gun sleeve drives the spinning bushing 6 to drive the body 2 to start rotating, and the spinning bushing 6 driving body 2 will also transmit the torque to the lock ring 7 body through the engagement of the engagement teeth of the contact end face thereof, so as to drive the lock ring 7 to rotate synchronously, and when the lock ring 7 rotates in the wedge-shaped space, it will rotate into the bottom of the locking groove 14 along the conical spiral line on the locking groove 14 of the core rod 1.

[0069] In some embodiments, the lock ring 7 is a thin-walled circular ring structure, and the metal base hardness at one end of the third engagement teeth 71 is greater than the metal base hardness at the other end of the lock ring 7.

[0070] The outer surface of the lock ring 7 is also coated with a lubricating coating.

[0071] Specifically, in the present embodiment, the lock ring 7 is as shown in Figure 5 and Figure 6As shown, it is a thin-walled circular ring part, which is composed of two parts of metal, the left side is a high hardness metal base with a hardness of HRC 50-60, and the left side end face is provided with meshing teeth which cooperate with the meshing teeth in the stepped hole 52 of the spinning bush 6, and the left side high hardness meshing teeth are not easy to deform in use; the right side of the lock ring 7 is a metal with lower hardness, with a hardness of HRC 30-35, which mainly plays a role in facilitating the plastic forming of the softer part of the lock ring 7, can accurately and timely extrude into the space of the wedge-shaped locking groove 14, and can provide sufficient locking performance to ensure the tensile and fatigue strength of the installed product. The two parts of metal with different hardness of the lock ring 7 are also processed by high-speed rotary friction welding, and the welding is a complete part, and after that, the excess metal at the welding position can be removed by simple turning processing.

[0072] The finished surface of the lock ring 7 is also coated with a special lubricating coating, which can more conveniently and stably extrude and spin the lock ring 7 into the space of the wedge-shaped locking groove 14 when the spinning bush 6 drives the body 2 to extrude and twist the lock ring 7.

[0073] As shown in Figure 1 , Figure 6 , Figure 7 and Figure 8 , the riveting process of this structure is as follows:

[0074] First, a riveting hole corresponding to the outer diameter of the core-pulling rivet is drilled on the to-be-riveted part and the base; then the assembled core-pulling rivet is inserted into the riveting hole of the to-be-riveted part, so that the cap on the shank 5 abuts against the support surface of the riveting hole of the to-be-riveted part; then the end of the core rod 1 is inserted into the chuck of the riveter, at this time the end flat structure of the core rod 1 is inserted into the flat slot of the riveter chuck, and the two are matched, then the spinning bush 6 of the core-pulling rivet is abutted by the end surface of the riveter head, and the entire blind bolt is tightly abutted in the mounting hole by applying axial force.

[0075] Subsequently, the riveter trigger is pressed, and the riveter starts to work. The riveter clamps the tail straight ring groove 11 of the core rod 1 of the core-pulling rivet through the chuck in the gun barrel of the riveter, and the chuck clamps the core rod 1 and starts to retreat under the action of gas pressure through the piston mechanism. At this time, the gun barrel of the riveter is still in the state of abutting against the fastener and will not move.

[0076] In the process of the chuck clamping the core rod 1 retreating, the head lower support surface of the core rod 1 compresses the driving body 2, which also moves towards the blind end plate surface. The driving body 2, the forming sleeve 4 and the shank 5 are welded into a complete whole by friction welding. In the process of the driving body 2 moving towards the plate surface, the driving forming sleeve 4 starts to deform by extrusion and expansion. In the process of the core rod 1 compressing the driving body 2 continuing to retreat, the forming sleeve 4 continues to deform by bulging, and finally a larger bulge is formed on the to-be-installed plate surface.

[0077] When the core rod 1 retreats to the final position, that is, the blocking step 15 of the core rod 1 and the blocking step 15 of the hole in the nail body 5 coincide, the core rod 1 cannot continue to retreat, and the rivet gun chuck is still continuously exerting a pulling force on the tail of the core rod 1. At this time, the gun sleeve is still in the state of abutting against the rotary pressure bushing 6. When the pulling force exerted by the rivet gun chuck on the tail of the core rod 1 increases to a certain value, the rotary pressure bushing 6 will be sheared off from the shearing groove 63 under the action of the counterforce. Under the action of the pulling force of the rivet gun chuck, the sheared rotary pressure bushing 6 will push the locking ring 7 to move towards the wedge-shaped space formed by the locking ring 7, and finally the locking ring 7 will be completely extruded into the wedge-shaped space. At this time, the pulling force on the tail of the core rod 1 is still continuously increasing under the driving of the rivet gun chuck. When the pulling force increases to the set value of the rivet gun, the second movement of the rivet gun will be triggered, that is, the gun sleeve on the gun head will start to rotate. At this time, the chuck in the gun sleeve is still clamping the annular groove at the tail of the core rod 1 and continuously exerting a stable pulling force. The pulling force is also completely exerted on the meshing tooth end surface of the rotary pressure bushing 6 through the counterforce.

[0078] During the rotation of the gun sleeve, the meshing teeth on the end surface of the gun sleeve and the meshing teeth on the end surface of the rotary pressure bushing 6 will drive the driving part of the rotary pressure bushing 6 to start synchronous rotation. Since the flat structure of the tail of the core rod 1 is clamped by the flat groove of the chuck, the core rod 1 will not rotate. Since the cross-shaped boss on the lower end surface of the core rod 1 and the cross-shaped groove on the end surface of the driving body 2 match and limit, the nail body 5 will not rotate. Only the gun sleeve drives the driving part of the rotary pressure bushing 6 to rotate.

[0079] During the rotation of the driving part of the rotary pressure bushing 6, the meshing teeth on the right side of the driving part of the rotary pressure bushing 6 and the meshing teeth on the body of the locking ring 7 will synchronously drive the deformed locking ring 7 to rotate. At this time, the locking ring 7 is subjected to a combined load of a pushing force and a torsional force exerted by the rotary pressure bushing 6, and the tail of the core rod 1 is still continuously subjected to a fixed pulling force exerted by the rivet gun chuck.

[0080] Under the rotational driving of the driving part of the rotary pressure bushing 6, the locking ring 7 also starts to rotate slightly. When the locking ring 7 rotates, it will rotate along the spiral line on the tapered inclined surface of the locking groove 14 of the core rod 1. Under the guidance of the spiral line and the pushing force exerted by the rotary pressure bushing 6, the locking ring 7 will spiral extrude and advance along the spiral line to a deeper part of the wedge-shaped locking space. When the locking ring 7 is completely spiral extruded into the lowest part of the wedge-shaped space, the locking ring 7 cannot continue to advance and rotate. When the rotation torque acting on the gun sleeve continues to increase, the torque also acts on the annular groove of the tail of the core rod 1 through the flat rod of the tail of the core rod 1 under the action of the counterforce. When the torque increases to a certain degree, the tail of the core rod 1 will be twisted off from the neck breaking groove under the combined action of the pulling force and the torque. At this time, the entire riveting process is completed.

[0081] After the core rod 1 is twisted off from the neck breaking groove, due to the existence of the convex helical line on the inclined surface of the locking groove 14 of the core rod 1, the friction force on the tapered surface of the locking groove 14 of the core rod 1 is increased, and the release and consumption of the pre-tightening force caused by the elastic slip between the locking ring 7 and the core rod 1 due to the existence of the tapered thread will not occur. Compared with the previous core-pulling rivet products, the invention and innovation content of the patent can effectively improve the pre-tightening force of such products by more than 0%.

[0082] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

[0083] The embodiments of the present application are intended to cover all such replacements, modifications and variations falling within the broad scope of the appended claims. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A preload-enhanced blind rivet bolt, characterized by: It includes a core rod, and a driving body, an expansion ring, a forming sleeve, a nail body, a locking ring and a spinning bushing sleeve sleeved on the core rod; The core rod is a slender rod structure, the end of the core rod is connected to the rivet gun chuck, the middle of the core rod is provided with a breaking groove, and the head end of the core rod is provided with a terminal; The driving body, the forming sleeve and the nail body are an integrally arranged tubular structure, the forming sleeve forms a flexible deformation area, and a receiving cavity for accommodating the expansion ring is provided inside the forming sleeve, and the driving body is clamped with the head end of the core rod; The spun bushing is a rotating body structure with a stepped hole provided inside, and the lock ring is arranged in the stepped hole and is engaged with the end face of the stepped hole of the spun bushing. The outer ring of the spun bushing is provided with a shear groove; The nail body is a hollow rotary structure with a stepped hole formed inside. A locking hole communicating with the stepped hole is formed inside the nail body, wherein the stepped hole cooperates with a blocking step formed in the middle of the core rod. A spiral locking groove with a conical structure is provided between the breaking groove and the blocking step, and the locking groove cooperates with the locking hole to form a wedge-shaped space; During riveting, the spinning bushing is first squeezed by the rivet gun head and the end face of the nail body.

2. The preload-enhanced blind rivet bolt according to claim 1, characterized in that: The end of the core rod is a flat structure and matches the flat groove provided in the rivet gun chuck. The core rod is provided with a straight ring groove and is clamped and fixed by the rivet gun chuck. The inner wall of the end of the core rod is provided with a cross-shaped anti-rotation tooth, and the end surface of the driving body is provided with a cross-shaped anti-rotation groove that matches the cross-shaped anti-rotation tooth, so that the driving body and the core rod are correspondingly engaged.

3. The preload-enhanced blind rivet bolt according to claim 2, characterized in that: A clamping ring groove is provided on one side of the middle portion of the core rod close to the straight ring groove, for interference fit with the inner hole of the spun bushing to clamp the spun bushing.

4. The preload-enhanced blind rivet bolt according to claim 1, characterized in that: The forming sleeve is a hollow tubular structure with a rotation groove provided therein. The thickness of the rotation groove at one end close to the nail body is greater than the thickness at one end close to the driving body, so as to form an accommodating cavity.

5. The preload-enhanced blind rivet bolt according to claim 4, characterized in that: The expansion ring is a circular rotating structure, the cross-sectional shape of which matches the shape of the rotating groove, and an inclined groove is provided in the middle of the circular ring.

6. The preload-enhanced blind rivet bolt according to claim 1, characterized in that: The driving end of the spinning bushing pushes the locking ring so that the locking ring is squeezed into the wedge-shaped space along the locking groove.

7. The preload-enhanced blind rivet bolt according to claim 1, characterized in that: The end face of the spinning bushing close to the rivet gun head is a conical surface with an angle range of 150 degrees to 160 degrees. The conical surface is provided with a first meshing tooth, which meshes with the end face of the rivet gun head.

8. The preload-enhanced blind rivet bolt according to claim 7, characterized in that: A second meshing tooth is provided on the end surface of the stepped hole provided in the spun bushing, and a third meshing tooth meshing with the second meshing tooth is provided on one end surface of the lock ring.

9. The preload-enhanced blind rivet bolt according to claim 8, characterized in that: The lock ring is a thin-walled circular ring structure, and the hardness of the metal matrix at one end of the third meshing tooth is greater than the hardness of the metal matrix at the other end of the lock ring.

10. The preload-enhanced blind rivet bolt according to claim 9, characterized in that: The outer surface of the lock ring is also coated with a lubricating coating.

Images